diff --git a/crypto/openssh/auth-pam.c b/crypto/openssh/auth-pam.c index 8f8625894c8e..77e9e2bae7d3 100644 --- a/crypto/openssh/auth-pam.c +++ b/crypto/openssh/auth-pam.c @@ -1,1261 +1,1262 @@ /*- * Copyright (c) 2002 Networks Associates Technology, Inc. * All rights reserved. * * This software was developed for the FreeBSD Project by ThinkSec AS and * NAI Labs, the Security Research Division of Network Associates, Inc. * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the * DARPA CHATS research program. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* * Copyright (c) 2003,2004 Damien Miller * Copyright (c) 2003,2004 Darren Tucker * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ /* Based on FreeBSD: src/crypto/openssh/auth2-pam-freebsd.c,v 1.11 2003/03/31 13:48:18 des */ #include "includes.h" #include #include #include #include #include #include #include #include #ifdef USE_PAM #if defined(HAVE_SECURITY_PAM_APPL_H) #include #elif defined (HAVE_PAM_PAM_APPL_H) #include #endif #if !defined(SSHD_PAM_SERVICE) extern char *__progname; # define SSHD_PAM_SERVICE __progname #endif /* OpenGroup RFC86.0 and XSSO specify no "const" on arguments */ #ifdef PAM_SUN_CODEBASE # define sshpam_const /* Solaris, HP-UX, SunOS */ #else # define sshpam_const const /* LinuxPAM, OpenPAM, AIX */ #endif /* Ambiguity in spec: is it an array of pointers or a pointer to an array? */ #ifdef PAM_SUN_CODEBASE # define PAM_MSG_MEMBER(msg, n, member) ((*(msg))[(n)].member) #else # define PAM_MSG_MEMBER(msg, n, member) ((msg)[(n)]->member) #endif #include "xmalloc.h" #include "buffer.h" #include "key.h" #include "hostfile.h" #include "auth.h" #include "auth-pam.h" #include "canohost.h" #include "log.h" #include "msg.h" #include "packet.h" #include "misc.h" #include "servconf.h" #include "ssh2.h" #include "auth-options.h" #ifdef GSSAPI #include "ssh-gss.h" #endif #include "monitor_wrap.h" #include "blacklist_client.h" extern ServerOptions options; extern Buffer loginmsg; extern int compat20; extern u_int utmp_len; /* so we don't silently change behaviour */ #ifdef USE_POSIX_THREADS # error "USE_POSIX_THREADS replaced by UNSUPPORTED_POSIX_THREADS_HACK" #endif /* * Formerly known as USE_POSIX_THREADS, using this is completely unsupported * and generally a bad idea. Use at own risk and do not expect support if * this breaks. */ #ifdef UNSUPPORTED_POSIX_THREADS_HACK #include /* * Avoid namespace clash when *not* using pthreads for systems *with* * pthreads, which unconditionally define pthread_t via sys/types.h * (e.g. Linux) */ typedef pthread_t sp_pthread_t; #else typedef pid_t sp_pthread_t; #endif struct pam_ctxt { sp_pthread_t pam_thread; int pam_psock; int pam_csock; int pam_done; }; static void sshpam_free_ctx(void *); static struct pam_ctxt *cleanup_ctxt; #ifndef UNSUPPORTED_POSIX_THREADS_HACK /* * Simulate threads with processes. */ static int sshpam_thread_status = -1; static mysig_t sshpam_oldsig; static void sshpam_sigchld_handler(int sig) { signal(SIGCHLD, SIG_DFL); if (cleanup_ctxt == NULL) return; /* handler called after PAM cleanup, shouldn't happen */ if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, WNOHANG) <= 0) { /* PAM thread has not exitted, privsep slave must have */ kill(cleanup_ctxt->pam_thread, SIGTERM); while (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, 0) == -1) { if (errno == EINTR) continue; return; } } if (WIFSIGNALED(sshpam_thread_status) && WTERMSIG(sshpam_thread_status) == SIGTERM) return; /* terminated by pthread_cancel */ if (!WIFEXITED(sshpam_thread_status)) sigdie("PAM: authentication thread exited unexpectedly"); if (WEXITSTATUS(sshpam_thread_status) != 0) sigdie("PAM: authentication thread exited uncleanly"); } /* ARGSUSED */ static void pthread_exit(void *value) { _exit(0); } /* ARGSUSED */ static int pthread_create(sp_pthread_t *thread, const void *attr, void *(*thread_start)(void *), void *arg) { pid_t pid; struct pam_ctxt *ctx = arg; sshpam_thread_status = -1; switch ((pid = fork())) { case -1: error("fork(): %s", strerror(errno)); return (-1); case 0: close(ctx->pam_psock); ctx->pam_psock = -1; thread_start(arg); _exit(1); default: *thread = pid; close(ctx->pam_csock); ctx->pam_csock = -1; sshpam_oldsig = signal(SIGCHLD, sshpam_sigchld_handler); return (0); } } static int pthread_cancel(sp_pthread_t thread) { signal(SIGCHLD, sshpam_oldsig); return (kill(thread, SIGTERM)); } /* ARGSUSED */ static int pthread_join(sp_pthread_t thread, void **value) { int status; if (sshpam_thread_status != -1) return (sshpam_thread_status); signal(SIGCHLD, sshpam_oldsig); while (waitpid(thread, &status, 0) == -1) { if (errno == EINTR) continue; fatal("%s: waitpid: %s", __func__, strerror(errno)); } return (status); } #endif static pam_handle_t *sshpam_handle = NULL; static int sshpam_err = 0; static int sshpam_authenticated = 0; static int sshpam_session_open = 0; static int sshpam_cred_established = 0; static int sshpam_account_status = -1; static int sshpam_maxtries_reached = 0; static char **sshpam_env = NULL; static Authctxt *sshpam_authctxt = NULL; static const char *sshpam_password = NULL; /* Some PAM implementations don't implement this */ #ifndef HAVE_PAM_GETENVLIST static char ** pam_getenvlist(pam_handle_t *pamh) { /* * XXX - If necessary, we can still support envrionment passing * for platforms without pam_getenvlist by searching for known * env vars (e.g. KRB5CCNAME) from the PAM environment. */ return NULL; } #endif /* * Some platforms, notably Solaris, do not enforce password complexity * rules during pam_chauthtok() if the real uid of the calling process * is 0, on the assumption that it's being called by "passwd" run by root. * This wraps pam_chauthtok and sets/restore the real uid so PAM will do * the right thing. */ #ifdef SSHPAM_CHAUTHTOK_NEEDS_RUID static int sshpam_chauthtok_ruid(pam_handle_t *pamh, int flags) { int result; if (sshpam_authctxt == NULL) fatal("PAM: sshpam_authctxt not initialized"); if (setreuid(sshpam_authctxt->pw->pw_uid, -1) == -1) fatal("%s: setreuid failed: %s", __func__, strerror(errno)); result = pam_chauthtok(pamh, flags); if (setreuid(0, -1) == -1) fatal("%s: setreuid failed: %s", __func__, strerror(errno)); return result; } # define pam_chauthtok(a,b) (sshpam_chauthtok_ruid((a), (b))) #endif void sshpam_password_change_required(int reqd) { debug3("%s %d", __func__, reqd); if (sshpam_authctxt == NULL) fatal("%s: PAM authctxt not initialized", __func__); sshpam_authctxt->force_pwchange = reqd; if (reqd) { no_port_forwarding_flag |= 2; no_agent_forwarding_flag |= 2; no_x11_forwarding_flag |= 2; } else { no_port_forwarding_flag &= ~2; no_agent_forwarding_flag &= ~2; no_x11_forwarding_flag &= ~2; } } /* Import regular and PAM environment from subprocess */ static void import_environments(Buffer *b) { char *env; u_int i, num_env; int err; debug3("PAM: %s entering", __func__); #ifndef UNSUPPORTED_POSIX_THREADS_HACK /* Import variables set by do_pam_account */ sshpam_account_status = buffer_get_int(b); sshpam_password_change_required(buffer_get_int(b)); /* Import environment from subprocess */ num_env = buffer_get_int(b); if (num_env > 1024) fatal("%s: received %u environment variables, expected <= 1024", __func__, num_env); sshpam_env = xcalloc(num_env + 1, sizeof(*sshpam_env)); debug3("PAM: num env strings %d", num_env); for(i = 0; i < num_env; i++) sshpam_env[i] = buffer_get_string(b, NULL); sshpam_env[num_env] = NULL; /* Import PAM environment from subprocess */ num_env = buffer_get_int(b); debug("PAM: num PAM env strings %d", num_env); for(i = 0; i < num_env; i++) { env = buffer_get_string(b, NULL); #ifdef HAVE_PAM_PUTENV /* Errors are not fatal here */ if ((err = pam_putenv(sshpam_handle, env)) != PAM_SUCCESS) { error("PAM: pam_putenv: %s", pam_strerror(sshpam_handle, sshpam_err)); } #endif } #endif } /* * Conversation function for authentication thread. */ static int sshpam_thread_conv(int n, sshpam_const struct pam_message **msg, struct pam_response **resp, void *data) { Buffer buffer; struct pam_ctxt *ctxt; struct pam_response *reply; int i; debug3("PAM: %s entering, %d messages", __func__, n); *resp = NULL; if (data == NULL) { error("PAM: conversation function passed a null context"); return (PAM_CONV_ERR); } ctxt = data; if (n <= 0 || n > PAM_MAX_NUM_MSG) return (PAM_CONV_ERR); if ((reply = calloc(n, sizeof(*reply))) == NULL) return (PAM_CONV_ERR); buffer_init(&buffer); for (i = 0; i < n; ++i) { switch (PAM_MSG_MEMBER(msg, i, msg_style)) { case PAM_PROMPT_ECHO_OFF: case PAM_PROMPT_ECHO_ON: buffer_put_cstring(&buffer, PAM_MSG_MEMBER(msg, i, msg)); if (ssh_msg_send(ctxt->pam_csock, PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1) goto fail; if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1) goto fail; if (buffer_get_char(&buffer) != PAM_AUTHTOK) goto fail; reply[i].resp = buffer_get_string(&buffer, NULL); break; case PAM_ERROR_MSG: case PAM_TEXT_INFO: buffer_put_cstring(&buffer, PAM_MSG_MEMBER(msg, i, msg)); if (ssh_msg_send(ctxt->pam_csock, PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1) goto fail; break; default: goto fail; } buffer_clear(&buffer); } buffer_free(&buffer); *resp = reply; return (PAM_SUCCESS); fail: for(i = 0; i < n; i++) { free(reply[i].resp); } free(reply); buffer_free(&buffer); return (PAM_CONV_ERR); } /* * Authentication thread. */ static void * sshpam_thread(void *ctxtp) { struct pam_ctxt *ctxt = ctxtp; Buffer buffer; struct pam_conv sshpam_conv; int flags = (options.permit_empty_passwd == 0 ? PAM_DISALLOW_NULL_AUTHTOK : 0); #ifndef UNSUPPORTED_POSIX_THREADS_HACK extern char **environ; char **env_from_pam; u_int i; const char *pam_user; const char **ptr_pam_user = &pam_user; char *tz = getenv("TZ"); sshpam_err = pam_get_item(sshpam_handle, PAM_USER, (sshpam_const void **)ptr_pam_user); if (sshpam_err != PAM_SUCCESS) goto auth_fail; environ[0] = NULL; if (tz != NULL) if (setenv("TZ", tz, 1) == -1) error("PAM: could not set TZ environment: %s", strerror(errno)); if (sshpam_authctxt != NULL) { setproctitle("%s [pam]", sshpam_authctxt->valid ? pam_user : "unknown"); } #endif sshpam_conv.conv = sshpam_thread_conv; sshpam_conv.appdata_ptr = ctxt; if (sshpam_authctxt == NULL) fatal("%s: PAM authctxt not initialized", __func__); buffer_init(&buffer); sshpam_err = pam_set_item(sshpam_handle, PAM_CONV, (const void *)&sshpam_conv); if (sshpam_err != PAM_SUCCESS) goto auth_fail; sshpam_err = pam_authenticate(sshpam_handle, flags); if (sshpam_err == PAM_MAXTRIES) sshpam_set_maxtries_reached(1); if (sshpam_err != PAM_SUCCESS) goto auth_fail; if (compat20) { if (!do_pam_account()) { sshpam_err = PAM_ACCT_EXPIRED; goto auth_fail; } if (sshpam_authctxt->force_pwchange) { sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK); if (sshpam_err != PAM_SUCCESS) goto auth_fail; sshpam_password_change_required(0); } } buffer_put_cstring(&buffer, "OK"); #ifndef UNSUPPORTED_POSIX_THREADS_HACK /* Export variables set by do_pam_account */ buffer_put_int(&buffer, sshpam_account_status); buffer_put_int(&buffer, sshpam_authctxt->force_pwchange); /* Export any environment strings set in child */ for(i = 0; environ[i] != NULL; i++) ; /* Count */ buffer_put_int(&buffer, i); for(i = 0; environ[i] != NULL; i++) buffer_put_cstring(&buffer, environ[i]); /* Export any environment strings set by PAM in child */ env_from_pam = pam_getenvlist(sshpam_handle); for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++) ; /* Count */ buffer_put_int(&buffer, i); for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++) buffer_put_cstring(&buffer, env_from_pam[i]); #endif /* UNSUPPORTED_POSIX_THREADS_HACK */ /* XXX - can't do much about an error here */ ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer); buffer_free(&buffer); pthread_exit(NULL); auth_fail: buffer_put_cstring(&buffer, pam_strerror(sshpam_handle, sshpam_err)); /* XXX - can't do much about an error here */ if (sshpam_err == PAM_ACCT_EXPIRED) ssh_msg_send(ctxt->pam_csock, PAM_ACCT_EXPIRED, &buffer); else if (sshpam_maxtries_reached) ssh_msg_send(ctxt->pam_csock, PAM_MAXTRIES, &buffer); else ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer); buffer_free(&buffer); pthread_exit(NULL); return (NULL); /* Avoid warning for non-pthread case */ } void sshpam_thread_cleanup(void) { struct pam_ctxt *ctxt = cleanup_ctxt; debug3("PAM: %s entering", __func__); if (ctxt != NULL && ctxt->pam_thread != 0) { pthread_cancel(ctxt->pam_thread); pthread_join(ctxt->pam_thread, NULL); close(ctxt->pam_psock); close(ctxt->pam_csock); memset(ctxt, 0, sizeof(*ctxt)); cleanup_ctxt = NULL; } } static int sshpam_null_conv(int n, sshpam_const struct pam_message **msg, struct pam_response **resp, void *data) { debug3("PAM: %s entering, %d messages", __func__, n); return (PAM_CONV_ERR); } static struct pam_conv null_conv = { sshpam_null_conv, NULL }; static int sshpam_store_conv(int n, sshpam_const struct pam_message **msg, struct pam_response **resp, void *data) { struct pam_response *reply; int i; size_t len; debug3("PAM: %s called with %d messages", __func__, n); *resp = NULL; if (n <= 0 || n > PAM_MAX_NUM_MSG) return (PAM_CONV_ERR); if ((reply = calloc(n, sizeof(*reply))) == NULL) return (PAM_CONV_ERR); for (i = 0; i < n; ++i) { switch (PAM_MSG_MEMBER(msg, i, msg_style)) { case PAM_ERROR_MSG: case PAM_TEXT_INFO: len = strlen(PAM_MSG_MEMBER(msg, i, msg)); buffer_append(&loginmsg, PAM_MSG_MEMBER(msg, i, msg), len); buffer_append(&loginmsg, "\n", 1 ); reply[i].resp_retcode = PAM_SUCCESS; break; default: goto fail; } } *resp = reply; return (PAM_SUCCESS); fail: for(i = 0; i < n; i++) { free(reply[i].resp); } free(reply); return (PAM_CONV_ERR); } static struct pam_conv store_conv = { sshpam_store_conv, NULL }; void sshpam_cleanup(void) { if (sshpam_handle == NULL || (use_privsep && !mm_is_monitor())) return; debug("PAM: cleanup"); pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv); if (sshpam_session_open) { debug("PAM: closing session"); pam_close_session(sshpam_handle, PAM_SILENT); sshpam_session_open = 0; } if (sshpam_cred_established) { debug("PAM: deleting credentials"); pam_setcred(sshpam_handle, PAM_DELETE_CRED); sshpam_cred_established = 0; } sshpam_authenticated = 0; pam_end(sshpam_handle, sshpam_err); sshpam_handle = NULL; } static int sshpam_init(Authctxt *authctxt) { const char *pam_rhost, *pam_user, *user = authctxt->user; const char **ptr_pam_user = &pam_user; struct ssh *ssh = active_state; /* XXX */ if (sshpam_handle != NULL) { /* We already have a PAM context; check if the user matches */ sshpam_err = pam_get_item(sshpam_handle, PAM_USER, (sshpam_const void **)ptr_pam_user); if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0) return (0); pam_end(sshpam_handle, sshpam_err); sshpam_handle = NULL; } debug("PAM: initializing for \"%s\"", user); sshpam_err = pam_start(SSHD_PAM_SERVICE, user, &store_conv, &sshpam_handle); sshpam_authctxt = authctxt; if (sshpam_err != PAM_SUCCESS) { pam_end(sshpam_handle, sshpam_err); sshpam_handle = NULL; return (-1); } pam_rhost = auth_get_canonical_hostname(ssh, options.use_dns); debug("PAM: setting PAM_RHOST to \"%s\"", pam_rhost); sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST, pam_rhost); if (sshpam_err != PAM_SUCCESS) { pam_end(sshpam_handle, sshpam_err); sshpam_handle = NULL; return (-1); } #ifdef PAM_TTY_KLUDGE /* * Some silly PAM modules (e.g. pam_time) require a TTY to operate. * sshd doesn't set the tty until too late in the auth process and * may not even set one (for tty-less connections) */ debug("PAM: setting PAM_TTY to \"ssh\""); sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, "ssh"); if (sshpam_err != PAM_SUCCESS) { pam_end(sshpam_handle, sshpam_err); sshpam_handle = NULL; return (-1); } #endif return (0); } static void * sshpam_init_ctx(Authctxt *authctxt) { struct pam_ctxt *ctxt; int socks[2]; debug3("PAM: %s entering", __func__); /* * Refuse to start if we don't have PAM enabled or do_pam_account * has previously failed. */ if (!options.use_pam || sshpam_account_status == 0) return NULL; /* Initialize PAM */ if (sshpam_init(authctxt) == -1) { error("PAM: initialization failed"); return (NULL); } ctxt = xcalloc(1, sizeof *ctxt); /* Start the authentication thread */ if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) { error("PAM: failed create sockets: %s", strerror(errno)); free(ctxt); return (NULL); } ctxt->pam_psock = socks[0]; ctxt->pam_csock = socks[1]; if (pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt) == -1) { error("PAM: failed to start authentication thread: %s", strerror(errno)); close(socks[0]); close(socks[1]); free(ctxt); return (NULL); } cleanup_ctxt = ctxt; return (ctxt); } static int sshpam_query(void *ctx, char **name, char **info, u_int *num, char ***prompts, u_int **echo_on) { struct ssh *ssh = active_state; /* XXX */ Buffer buffer; struct pam_ctxt *ctxt = ctx; size_t plen; u_char type; char *msg; size_t len, mlen; debug3("PAM: %s entering", __func__); buffer_init(&buffer); *name = xstrdup(""); *info = xstrdup(""); *prompts = xmalloc(sizeof(char *)); **prompts = NULL; plen = 0; *echo_on = xmalloc(sizeof(u_int)); while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) { type = buffer_get_char(&buffer); msg = buffer_get_string(&buffer, NULL); mlen = strlen(msg); switch (type) { case PAM_PROMPT_ECHO_ON: case PAM_PROMPT_ECHO_OFF: *num = 1; len = plen + mlen + 1; **prompts = xreallocarray(**prompts, 1, len); strlcpy(**prompts + plen, msg, len - plen); plen += mlen; **echo_on = (type == PAM_PROMPT_ECHO_ON); free(msg); return (0); case PAM_ERROR_MSG: case PAM_TEXT_INFO: /* accumulate messages */ len = plen + mlen + 2; **prompts = xreallocarray(**prompts, 1, len); strlcpy(**prompts + plen, msg, len - plen); plen += mlen; strlcat(**prompts + plen, "\n", len - plen); plen++; free(msg); break; case PAM_ACCT_EXPIRED: case PAM_MAXTRIES: if (type == PAM_ACCT_EXPIRED) sshpam_account_status = 0; if (type == PAM_MAXTRIES) sshpam_set_maxtries_reached(1); /* FALLTHROUGH */ case PAM_AUTH_ERR: debug3("PAM: %s", pam_strerror(sshpam_handle, type)); if (**prompts != NULL && strlen(**prompts) != 0) { *info = **prompts; **prompts = NULL; *num = 0; **echo_on = 0; ctxt->pam_done = -1; free(msg); return 0; } /* FALLTHROUGH */ case PAM_SUCCESS: if (**prompts != NULL) { /* drain any accumulated messages */ debug("PAM: %s", **prompts); buffer_append(&loginmsg, **prompts, strlen(**prompts)); free(**prompts); **prompts = NULL; } if (type == PAM_SUCCESS) { if (!sshpam_authctxt->valid || (sshpam_authctxt->pw->pw_uid == 0 && options.permit_root_login != PERMIT_YES)) fatal("Internal error: PAM auth " "succeeded when it should have " "failed"); import_environments(&buffer); *num = 0; **echo_on = 0; ctxt->pam_done = 1; free(msg); return (0); } - BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL); + BLACKLIST_NOTIFY(BLACKLIST_BAD_USER, + sshpam_authctxt->user); error("PAM: %s for %s%.100s from %.100s", msg, sshpam_authctxt->valid ? "" : "illegal user ", sshpam_authctxt->user, auth_get_canonical_hostname(ssh, options.use_dns)); /* FALLTHROUGH */ default: *num = 0; **echo_on = 0; free(msg); ctxt->pam_done = -1; return (-1); } } return (-1); } /* * Returns a junk password of identical length to that the user supplied. * Used to mitigate timing attacks against crypt(3)/PAM stacks that * vary processing time in proportion to password length. */ static char * fake_password(const char *wire_password) { const char junk[] = "\b\n\r\177INCORRECT"; char *ret = NULL; size_t i, l = wire_password != NULL ? strlen(wire_password) : 0; if (l >= INT_MAX) fatal("%s: password length too long: %zu", __func__, l); ret = malloc(l + 1); for (i = 0; i < l; i++) ret[i] = junk[i % (sizeof(junk) - 1)]; ret[i] = '\0'; return ret; } /* XXX - see also comment in auth-chall.c:verify_response */ static int sshpam_respond(void *ctx, u_int num, char **resp) { Buffer buffer; struct pam_ctxt *ctxt = ctx; char *fake; debug2("PAM: %s entering, %u responses", __func__, num); switch (ctxt->pam_done) { case 1: sshpam_authenticated = 1; return (0); case 0: break; default: return (-1); } if (num != 1) { error("PAM: expected one response, got %u", num); return (-1); } buffer_init(&buffer); if (sshpam_authctxt->valid && (sshpam_authctxt->pw->pw_uid != 0 || options.permit_root_login == PERMIT_YES)) buffer_put_cstring(&buffer, *resp); else { fake = fake_password(*resp); buffer_put_cstring(&buffer, fake); free(fake); } if (ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer) == -1) { buffer_free(&buffer); return (-1); } buffer_free(&buffer); return (1); } static void sshpam_free_ctx(void *ctxtp) { struct pam_ctxt *ctxt = ctxtp; debug3("PAM: %s entering", __func__); sshpam_thread_cleanup(); free(ctxt); /* * We don't call sshpam_cleanup() here because we may need the PAM * handle at a later stage, e.g. when setting up a session. It's * still on the cleanup list, so pam_end() *will* be called before * the server process terminates. */ } KbdintDevice sshpam_device = { "pam", sshpam_init_ctx, sshpam_query, sshpam_respond, sshpam_free_ctx }; KbdintDevice mm_sshpam_device = { "pam", mm_sshpam_init_ctx, mm_sshpam_query, mm_sshpam_respond, mm_sshpam_free_ctx }; /* * This replaces auth-pam.c */ void start_pam(Authctxt *authctxt) { if (!options.use_pam) fatal("PAM: initialisation requested when UsePAM=no"); if (sshpam_init(authctxt) == -1) fatal("PAM: initialisation failed"); } void finish_pam(void) { sshpam_cleanup(); } u_int do_pam_account(void) { debug("%s: called", __func__); if (sshpam_account_status != -1) return (sshpam_account_status); sshpam_err = pam_acct_mgmt(sshpam_handle, 0); debug3("PAM: %s pam_acct_mgmt = %d (%s)", __func__, sshpam_err, pam_strerror(sshpam_handle, sshpam_err)); if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD) { sshpam_account_status = 0; return (sshpam_account_status); } if (sshpam_err == PAM_NEW_AUTHTOK_REQD) sshpam_password_change_required(1); sshpam_account_status = 1; return (sshpam_account_status); } void do_pam_setcred(int init) { sshpam_err = pam_set_item(sshpam_handle, PAM_CONV, (const void *)&store_conv); if (sshpam_err != PAM_SUCCESS) fatal("PAM: failed to set PAM_CONV: %s", pam_strerror(sshpam_handle, sshpam_err)); if (init) { debug("PAM: establishing credentials"); sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED); } else { debug("PAM: reinitializing credentials"); sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED); } if (sshpam_err == PAM_SUCCESS) { sshpam_cred_established = 1; return; } if (sshpam_authenticated) fatal("PAM: pam_setcred(): %s", pam_strerror(sshpam_handle, sshpam_err)); else debug("PAM: pam_setcred(): %s", pam_strerror(sshpam_handle, sshpam_err)); } static int sshpam_tty_conv(int n, sshpam_const struct pam_message **msg, struct pam_response **resp, void *data) { char input[PAM_MAX_MSG_SIZE]; struct pam_response *reply; int i; debug3("PAM: %s called with %d messages", __func__, n); *resp = NULL; if (n <= 0 || n > PAM_MAX_NUM_MSG || !isatty(STDIN_FILENO)) return (PAM_CONV_ERR); if ((reply = calloc(n, sizeof(*reply))) == NULL) return (PAM_CONV_ERR); for (i = 0; i < n; ++i) { switch (PAM_MSG_MEMBER(msg, i, msg_style)) { case PAM_PROMPT_ECHO_OFF: reply[i].resp = read_passphrase(PAM_MSG_MEMBER(msg, i, msg), RP_ALLOW_STDIN); reply[i].resp_retcode = PAM_SUCCESS; break; case PAM_PROMPT_ECHO_ON: fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg)); if (fgets(input, sizeof input, stdin) == NULL) input[0] = '\0'; if ((reply[i].resp = strdup(input)) == NULL) goto fail; reply[i].resp_retcode = PAM_SUCCESS; break; case PAM_ERROR_MSG: case PAM_TEXT_INFO: fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg)); reply[i].resp_retcode = PAM_SUCCESS; break; default: goto fail; } } *resp = reply; return (PAM_SUCCESS); fail: for(i = 0; i < n; i++) { free(reply[i].resp); } free(reply); return (PAM_CONV_ERR); } static struct pam_conv tty_conv = { sshpam_tty_conv, NULL }; /* * XXX this should be done in the authentication phase, but ssh1 doesn't * support that */ void do_pam_chauthtok(void) { if (use_privsep) fatal("Password expired (unable to change with privsep)"); sshpam_err = pam_set_item(sshpam_handle, PAM_CONV, (const void *)&tty_conv); if (sshpam_err != PAM_SUCCESS) fatal("PAM: failed to set PAM_CONV: %s", pam_strerror(sshpam_handle, sshpam_err)); debug("PAM: changing password"); sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK); if (sshpam_err != PAM_SUCCESS) fatal("PAM: pam_chauthtok(): %s", pam_strerror(sshpam_handle, sshpam_err)); } void do_pam_session(void) { debug3("PAM: opening session"); sshpam_err = pam_set_item(sshpam_handle, PAM_CONV, (const void *)&store_conv); if (sshpam_err != PAM_SUCCESS) fatal("PAM: failed to set PAM_CONV: %s", pam_strerror(sshpam_handle, sshpam_err)); sshpam_err = pam_open_session(sshpam_handle, 0); if (sshpam_err == PAM_SUCCESS) sshpam_session_open = 1; else { sshpam_session_open = 0; disable_forwarding(); error("PAM: pam_open_session(): %s", pam_strerror(sshpam_handle, sshpam_err)); } } int is_pam_session_open(void) { return sshpam_session_open; } /* * Set a PAM environment string. We need to do this so that the session * modules can handle things like Kerberos/GSI credentials that appear * during the ssh authentication process. */ int do_pam_putenv(char *name, char *value) { int ret = 1; #ifdef HAVE_PAM_PUTENV char *compound; size_t len; len = strlen(name) + strlen(value) + 2; compound = xmalloc(len); snprintf(compound, len, "%s=%s", name, value); ret = pam_putenv(sshpam_handle, compound); free(compound); #endif return (ret); } char ** fetch_pam_child_environment(void) { return sshpam_env; } char ** fetch_pam_environment(void) { return (pam_getenvlist(sshpam_handle)); } void free_pam_environment(char **env) { char **envp; if (env == NULL) return; for (envp = env; *envp; envp++) free(*envp); free(env); } /* * "Blind" conversation function for password authentication. Assumes that * echo-off prompts are for the password and stores messages for later * display. */ static int sshpam_passwd_conv(int n, sshpam_const struct pam_message **msg, struct pam_response **resp, void *data) { struct pam_response *reply; int i; size_t len; debug3("PAM: %s called with %d messages", __func__, n); *resp = NULL; if (n <= 0 || n > PAM_MAX_NUM_MSG) return (PAM_CONV_ERR); if ((reply = calloc(n, sizeof(*reply))) == NULL) return (PAM_CONV_ERR); for (i = 0; i < n; ++i) { switch (PAM_MSG_MEMBER(msg, i, msg_style)) { case PAM_PROMPT_ECHO_OFF: if (sshpam_password == NULL) goto fail; if ((reply[i].resp = strdup(sshpam_password)) == NULL) goto fail; reply[i].resp_retcode = PAM_SUCCESS; break; case PAM_ERROR_MSG: case PAM_TEXT_INFO: len = strlen(PAM_MSG_MEMBER(msg, i, msg)); if (len > 0) { buffer_append(&loginmsg, PAM_MSG_MEMBER(msg, i, msg), len); buffer_append(&loginmsg, "\n", 1); } if ((reply[i].resp = strdup("")) == NULL) goto fail; reply[i].resp_retcode = PAM_SUCCESS; break; default: goto fail; } } *resp = reply; return (PAM_SUCCESS); fail: for(i = 0; i < n; i++) { free(reply[i].resp); } free(reply); return (PAM_CONV_ERR); } static struct pam_conv passwd_conv = { sshpam_passwd_conv, NULL }; /* * Attempt password authentication via PAM */ int sshpam_auth_passwd(Authctxt *authctxt, const char *password) { int flags = (options.permit_empty_passwd == 0 ? PAM_DISALLOW_NULL_AUTHTOK : 0); char *fake = NULL; if (!options.use_pam || sshpam_handle == NULL) fatal("PAM: %s called when PAM disabled or failed to " "initialise.", __func__); sshpam_password = password; sshpam_authctxt = authctxt; /* * If the user logging in is invalid, or is root but is not permitted * by PermitRootLogin, use an invalid password to prevent leaking * information via timing (eg if the PAM config has a delay on fail). */ if (!authctxt->valid || (authctxt->pw->pw_uid == 0 && options.permit_root_login != PERMIT_YES)) sshpam_password = fake = fake_password(password); sshpam_err = pam_set_item(sshpam_handle, PAM_CONV, (const void *)&passwd_conv); if (sshpam_err != PAM_SUCCESS) fatal("PAM: %s: failed to set PAM_CONV: %s", __func__, pam_strerror(sshpam_handle, sshpam_err)); sshpam_err = pam_authenticate(sshpam_handle, flags); sshpam_password = NULL; free(fake); if (sshpam_err == PAM_MAXTRIES) sshpam_set_maxtries_reached(1); if (sshpam_err == PAM_SUCCESS && authctxt->valid) { debug("PAM: password authentication accepted for %.100s", authctxt->user); return 1; } else { debug("PAM: password authentication failed for %.100s: %s", authctxt->valid ? authctxt->user : "an illegal user", pam_strerror(sshpam_handle, sshpam_err)); return 0; } } int sshpam_get_maxtries_reached(void) { return sshpam_maxtries_reached; } void sshpam_set_maxtries_reached(int reached) { if (reached == 0 || sshpam_maxtries_reached) return; sshpam_maxtries_reached = 1; options.password_authentication = 0; options.kbd_interactive_authentication = 0; options.challenge_response_authentication = 0; } #endif /* USE_PAM */ diff --git a/crypto/openssh/auth.c b/crypto/openssh/auth.c index a769f31e1bbb..1343ea0938a7 100644 --- a/crypto/openssh/auth.c +++ b/crypto/openssh/auth.c @@ -1,915 +1,915 @@ /* $OpenBSD: auth.c,v 1.119 2016/12/15 21:29:05 dtucker Exp $ */ /* * Copyright (c) 2000 Markus Friedl. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include "includes.h" __RCSID("$FreeBSD$"); #include #include #include #include #include #include #ifdef HAVE_PATHS_H # include #endif #include #ifdef HAVE_LOGIN_H #include #endif #ifdef USE_SHADOW #include #endif #ifdef HAVE_LIBGEN_H #include #endif #include #include #include #include #include #include #include "xmalloc.h" #include "match.h" #include "groupaccess.h" #include "log.h" #include "buffer.h" #include "misc.h" #include "servconf.h" #include "key.h" #include "hostfile.h" #include "auth.h" #include "auth-options.h" #include "canohost.h" #include "uidswap.h" #include "packet.h" #include "loginrec.h" #ifdef GSSAPI #include "ssh-gss.h" #endif #include "authfile.h" #include "monitor_wrap.h" #include "authfile.h" #include "ssherr.h" #include "compat.h" #include "blacklist_client.h" /* import */ extern ServerOptions options; extern int use_privsep; extern Buffer loginmsg; extern struct passwd *privsep_pw; /* Debugging messages */ Buffer auth_debug; int auth_debug_init; /* * Check if the user is allowed to log in via ssh. If user is listed * in DenyUsers or one of user's groups is listed in DenyGroups, false * will be returned. If AllowUsers isn't empty and user isn't listed * there, or if AllowGroups isn't empty and one of user's groups isn't * listed there, false will be returned. * If the user's shell is not executable, false will be returned. * Otherwise true is returned. */ int allowed_user(struct passwd * pw) { struct ssh *ssh = active_state; /* XXX */ struct stat st; const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL; u_int i; int r; #ifdef USE_SHADOW struct spwd *spw = NULL; #endif /* Shouldn't be called if pw is NULL, but better safe than sorry... */ if (!pw || !pw->pw_name) return 0; #ifdef USE_SHADOW if (!options.use_pam) spw = getspnam(pw->pw_name); #ifdef HAS_SHADOW_EXPIRE if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw)) return 0; #endif /* HAS_SHADOW_EXPIRE */ #endif /* USE_SHADOW */ /* grab passwd field for locked account check */ passwd = pw->pw_passwd; #ifdef USE_SHADOW if (spw != NULL) #ifdef USE_LIBIAF passwd = get_iaf_password(pw); #else passwd = spw->sp_pwdp; #endif /* USE_LIBIAF */ #endif /* check for locked account */ if (!options.use_pam && passwd && *passwd) { int locked = 0; #ifdef LOCKED_PASSWD_STRING if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0) locked = 1; #endif #ifdef LOCKED_PASSWD_PREFIX if (strncmp(passwd, LOCKED_PASSWD_PREFIX, strlen(LOCKED_PASSWD_PREFIX)) == 0) locked = 1; #endif #ifdef LOCKED_PASSWD_SUBSTR if (strstr(passwd, LOCKED_PASSWD_SUBSTR)) locked = 1; #endif #ifdef USE_LIBIAF free((void *) passwd); #endif /* USE_LIBIAF */ if (locked) { logit("User %.100s not allowed because account is locked", pw->pw_name); return 0; } } /* * Deny if shell does not exist or is not executable unless we * are chrooting. */ if (options.chroot_directory == NULL || strcasecmp(options.chroot_directory, "none") == 0) { char *shell = xstrdup((pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell); /* empty = /bin/sh */ if (stat(shell, &st) != 0) { logit("User %.100s not allowed because shell %.100s " "does not exist", pw->pw_name, shell); free(shell); return 0; } if (S_ISREG(st.st_mode) == 0 || (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) { logit("User %.100s not allowed because shell %.100s " "is not executable", pw->pw_name, shell); free(shell); return 0; } free(shell); } if (options.num_deny_users > 0 || options.num_allow_users > 0 || options.num_deny_groups > 0 || options.num_allow_groups > 0) { hostname = auth_get_canonical_hostname(ssh, options.use_dns); ipaddr = ssh_remote_ipaddr(ssh); } /* Return false if user is listed in DenyUsers */ if (options.num_deny_users > 0) { for (i = 0; i < options.num_deny_users; i++) { r = match_user(pw->pw_name, hostname, ipaddr, options.deny_users[i]); if (r < 0) { fatal("Invalid DenyUsers pattern \"%.100s\"", options.deny_users[i]); } else if (r != 0) { logit("User %.100s from %.100s not allowed " "because listed in DenyUsers", pw->pw_name, hostname); return 0; } } } /* Return false if AllowUsers isn't empty and user isn't listed there */ if (options.num_allow_users > 0) { for (i = 0; i < options.num_allow_users; i++) { r = match_user(pw->pw_name, hostname, ipaddr, options.allow_users[i]); if (r < 0) { fatal("Invalid AllowUsers pattern \"%.100s\"", options.allow_users[i]); } else if (r == 1) break; } /* i < options.num_allow_users iff we break for loop */ if (i >= options.num_allow_users) { logit("User %.100s from %.100s not allowed because " "not listed in AllowUsers", pw->pw_name, hostname); return 0; } } if (options.num_deny_groups > 0 || options.num_allow_groups > 0) { /* Get the user's group access list (primary and supplementary) */ if (ga_init(pw->pw_name, pw->pw_gid) == 0) { logit("User %.100s from %.100s not allowed because " "not in any group", pw->pw_name, hostname); return 0; } /* Return false if one of user's groups is listed in DenyGroups */ if (options.num_deny_groups > 0) if (ga_match(options.deny_groups, options.num_deny_groups)) { ga_free(); logit("User %.100s from %.100s not allowed " "because a group is listed in DenyGroups", pw->pw_name, hostname); return 0; } /* * Return false if AllowGroups isn't empty and one of user's groups * isn't listed there */ if (options.num_allow_groups > 0) if (!ga_match(options.allow_groups, options.num_allow_groups)) { ga_free(); logit("User %.100s from %.100s not allowed " "because none of user's groups are listed " "in AllowGroups", pw->pw_name, hostname); return 0; } ga_free(); } #ifdef CUSTOM_SYS_AUTH_ALLOWED_USER if (!sys_auth_allowed_user(pw, &loginmsg)) return 0; #endif /* We found no reason not to let this user try to log on... */ return 1; } void auth_info(Authctxt *authctxt, const char *fmt, ...) { va_list ap; int i; free(authctxt->info); authctxt->info = NULL; va_start(ap, fmt); i = vasprintf(&authctxt->info, fmt, ap); va_end(ap); if (i < 0 || authctxt->info == NULL) fatal("vasprintf failed"); } void auth_log(Authctxt *authctxt, int authenticated, int partial, const char *method, const char *submethod) { struct ssh *ssh = active_state; /* XXX */ void (*authlog) (const char *fmt,...) = verbose; char *authmsg; if (use_privsep && !mm_is_monitor() && !authctxt->postponed) return; /* Raise logging level */ if (authenticated == 1 || !authctxt->valid || authctxt->failures >= options.max_authtries / 2 || strcmp(method, "password") == 0) authlog = logit; if (authctxt->postponed) authmsg = "Postponed"; else if (partial) authmsg = "Partial"; else { authmsg = authenticated ? "Accepted" : "Failed"; if (authenticated) - BLACKLIST_NOTIFY(BLACKLIST_AUTH_OK); + BLACKLIST_NOTIFY(BLACKLIST_AUTH_OK, "ssh"); } authlog("%s %s%s%s for %s%.100s from %.200s port %d ssh2%s%s", authmsg, method, submethod != NULL ? "/" : "", submethod == NULL ? "" : submethod, authctxt->valid ? "" : "invalid user ", authctxt->user, ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), authctxt->info != NULL ? ": " : "", authctxt->info != NULL ? authctxt->info : ""); free(authctxt->info); authctxt->info = NULL; #ifdef CUSTOM_FAILED_LOGIN if (authenticated == 0 && !authctxt->postponed && (strcmp(method, "password") == 0 || strncmp(method, "keyboard-interactive", 20) == 0 || strcmp(method, "challenge-response") == 0)) record_failed_login(authctxt->user, auth_get_canonical_hostname(ssh, options.use_dns), "ssh"); # ifdef WITH_AIXAUTHENTICATE if (authenticated) sys_auth_record_login(authctxt->user, auth_get_canonical_hostname(ssh, options.use_dns), "ssh", &loginmsg); # endif #endif #ifdef SSH_AUDIT_EVENTS if (authenticated == 0 && !authctxt->postponed) audit_event(audit_classify_auth(method)); #endif } void auth_maxtries_exceeded(Authctxt *authctxt) { struct ssh *ssh = active_state; /* XXX */ error("maximum authentication attempts exceeded for " "%s%.100s from %.200s port %d ssh2", authctxt->valid ? "" : "invalid user ", authctxt->user, ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); packet_disconnect("Too many authentication failures"); /* NOTREACHED */ } /* * Check whether root logins are disallowed. */ int auth_root_allowed(const char *method) { struct ssh *ssh = active_state; /* XXX */ switch (options.permit_root_login) { case PERMIT_YES: return 1; case PERMIT_NO_PASSWD: if (strcmp(method, "publickey") == 0 || strcmp(method, "hostbased") == 0 || strcmp(method, "gssapi-with-mic") == 0) return 1; break; case PERMIT_FORCED_ONLY: if (forced_command) { logit("Root login accepted for forced command."); return 1; } break; } logit("ROOT LOGIN REFUSED FROM %.200s port %d", ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); return 0; } /* * Given a template and a passwd structure, build a filename * by substituting % tokenised options. Currently, %% becomes '%', * %h becomes the home directory and %u the username. * * This returns a buffer allocated by xmalloc. */ char * expand_authorized_keys(const char *filename, struct passwd *pw) { char *file, ret[PATH_MAX]; int i; file = percent_expand(filename, "h", pw->pw_dir, "u", pw->pw_name, (char *)NULL); /* * Ensure that filename starts anchored. If not, be backward * compatible and prepend the '%h/' */ if (*file == '/') return (file); i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file); if (i < 0 || (size_t)i >= sizeof(ret)) fatal("expand_authorized_keys: path too long"); free(file); return (xstrdup(ret)); } char * authorized_principals_file(struct passwd *pw) { if (options.authorized_principals_file == NULL) return NULL; return expand_authorized_keys(options.authorized_principals_file, pw); } /* return ok if key exists in sysfile or userfile */ HostStatus check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host, const char *sysfile, const char *userfile) { char *user_hostfile; struct stat st; HostStatus host_status; struct hostkeys *hostkeys; const struct hostkey_entry *found; hostkeys = init_hostkeys(); load_hostkeys(hostkeys, host, sysfile); if (userfile != NULL) { user_hostfile = tilde_expand_filename(userfile, pw->pw_uid); if (options.strict_modes && (stat(user_hostfile, &st) == 0) && ((st.st_uid != 0 && st.st_uid != pw->pw_uid) || (st.st_mode & 022) != 0)) { logit("Authentication refused for %.100s: " "bad owner or modes for %.200s", pw->pw_name, user_hostfile); auth_debug_add("Ignored %.200s: bad ownership or modes", user_hostfile); } else { temporarily_use_uid(pw); load_hostkeys(hostkeys, host, user_hostfile); restore_uid(); } free(user_hostfile); } host_status = check_key_in_hostkeys(hostkeys, key, &found); if (host_status == HOST_REVOKED) error("WARNING: revoked key for %s attempted authentication", found->host); else if (host_status == HOST_OK) debug("%s: key for %s found at %s:%ld", __func__, found->host, found->file, found->line); else debug("%s: key for host %s not found", __func__, host); free_hostkeys(hostkeys); return host_status; } /* * Check a given path for security. This is defined as all components * of the path to the file must be owned by either the owner of * of the file or root and no directories must be group or world writable. * * XXX Should any specific check be done for sym links ? * * Takes a file name, its stat information (preferably from fstat() to * avoid races), the uid of the expected owner, their home directory and an * error buffer plus max size as arguments. * * Returns 0 on success and -1 on failure */ int auth_secure_path(const char *name, struct stat *stp, const char *pw_dir, uid_t uid, char *err, size_t errlen) { char buf[PATH_MAX], homedir[PATH_MAX]; char *cp; int comparehome = 0; struct stat st; if (realpath(name, buf) == NULL) { snprintf(err, errlen, "realpath %s failed: %s", name, strerror(errno)); return -1; } if (pw_dir != NULL && realpath(pw_dir, homedir) != NULL) comparehome = 1; if (!S_ISREG(stp->st_mode)) { snprintf(err, errlen, "%s is not a regular file", buf); return -1; } if ((!platform_sys_dir_uid(stp->st_uid) && stp->st_uid != uid) || (stp->st_mode & 022) != 0) { snprintf(err, errlen, "bad ownership or modes for file %s", buf); return -1; } /* for each component of the canonical path, walking upwards */ for (;;) { if ((cp = dirname(buf)) == NULL) { snprintf(err, errlen, "dirname() failed"); return -1; } strlcpy(buf, cp, sizeof(buf)); if (stat(buf, &st) < 0 || (!platform_sys_dir_uid(st.st_uid) && st.st_uid != uid) || (st.st_mode & 022) != 0) { snprintf(err, errlen, "bad ownership or modes for directory %s", buf); return -1; } /* If are past the homedir then we can stop */ if (comparehome && strcmp(homedir, buf) == 0) break; /* * dirname should always complete with a "/" path, * but we can be paranoid and check for "." too */ if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0)) break; } return 0; } /* * Version of secure_path() that accepts an open file descriptor to * avoid races. * * Returns 0 on success and -1 on failure */ static int secure_filename(FILE *f, const char *file, struct passwd *pw, char *err, size_t errlen) { struct stat st; /* check the open file to avoid races */ if (fstat(fileno(f), &st) < 0) { snprintf(err, errlen, "cannot stat file %s: %s", file, strerror(errno)); return -1; } return auth_secure_path(file, &st, pw->pw_dir, pw->pw_uid, err, errlen); } static FILE * auth_openfile(const char *file, struct passwd *pw, int strict_modes, int log_missing, char *file_type) { char line[1024]; struct stat st; int fd; FILE *f; if ((fd = open(file, O_RDONLY|O_NONBLOCK)) == -1) { if (log_missing || errno != ENOENT) debug("Could not open %s '%s': %s", file_type, file, strerror(errno)); return NULL; } if (fstat(fd, &st) < 0) { close(fd); return NULL; } if (!S_ISREG(st.st_mode)) { logit("User %s %s %s is not a regular file", pw->pw_name, file_type, file); close(fd); return NULL; } unset_nonblock(fd); if ((f = fdopen(fd, "r")) == NULL) { close(fd); return NULL; } if (strict_modes && secure_filename(f, file, pw, line, sizeof(line)) != 0) { fclose(f); logit("Authentication refused: %s", line); auth_debug_add("Ignored %s: %s", file_type, line); return NULL; } return f; } FILE * auth_openkeyfile(const char *file, struct passwd *pw, int strict_modes) { return auth_openfile(file, pw, strict_modes, 1, "authorized keys"); } FILE * auth_openprincipals(const char *file, struct passwd *pw, int strict_modes) { return auth_openfile(file, pw, strict_modes, 0, "authorized principals"); } struct passwd * getpwnamallow(const char *user) { struct ssh *ssh = active_state; /* XXX */ #ifdef HAVE_LOGIN_CAP extern login_cap_t *lc; #ifdef BSD_AUTH auth_session_t *as; #endif #endif struct passwd *pw; struct connection_info *ci = get_connection_info(1, options.use_dns); ci->user = user; parse_server_match_config(&options, ci); #if defined(_AIX) && defined(HAVE_SETAUTHDB) aix_setauthdb(user); #endif pw = getpwnam(user); #if defined(_AIX) && defined(HAVE_SETAUTHDB) aix_restoreauthdb(); #endif #ifdef HAVE_CYGWIN /* * Windows usernames are case-insensitive. To avoid later problems * when trying to match the username, the user is only allowed to * login if the username is given in the same case as stored in the * user database. */ if (pw != NULL && strcmp(user, pw->pw_name) != 0) { logit("Login name %.100s does not match stored username %.100s", user, pw->pw_name); pw = NULL; } #endif if (pw == NULL) { - BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL); + BLACKLIST_NOTIFY(BLACKLIST_BAD_USER, user); logit("Invalid user %.100s from %.100s port %d", user, ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); #ifdef CUSTOM_FAILED_LOGIN record_failed_login(user, auth_get_canonical_hostname(ssh, options.use_dns), "ssh"); #endif #ifdef SSH_AUDIT_EVENTS audit_event(SSH_INVALID_USER); #endif /* SSH_AUDIT_EVENTS */ return (NULL); } if (!allowed_user(pw)) return (NULL); #ifdef HAVE_LOGIN_CAP if ((lc = login_getpwclass(pw)) == NULL) { debug("unable to get login class: %s", user); return (NULL); } #ifdef BSD_AUTH if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 || auth_approval(as, lc, pw->pw_name, "ssh") <= 0) { debug("Approval failure for %s", user); pw = NULL; } if (as != NULL) auth_close(as); #endif #endif if (pw != NULL) return (pwcopy(pw)); return (NULL); } /* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */ int auth_key_is_revoked(Key *key) { char *fp = NULL; int r; if (options.revoked_keys_file == NULL) return 0; if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) { r = SSH_ERR_ALLOC_FAIL; error("%s: fingerprint key: %s", __func__, ssh_err(r)); goto out; } r = sshkey_check_revoked(key, options.revoked_keys_file); switch (r) { case 0: break; /* not revoked */ case SSH_ERR_KEY_REVOKED: error("Authentication key %s %s revoked by file %s", sshkey_type(key), fp, options.revoked_keys_file); goto out; default: error("Error checking authentication key %s %s in " "revoked keys file %s: %s", sshkey_type(key), fp, options.revoked_keys_file, ssh_err(r)); goto out; } /* Success */ r = 0; out: free(fp); return r == 0 ? 0 : 1; } void auth_debug_add(const char *fmt,...) { char buf[1024]; va_list args; if (!auth_debug_init) return; va_start(args, fmt); vsnprintf(buf, sizeof(buf), fmt, args); va_end(args); buffer_put_cstring(&auth_debug, buf); } void auth_debug_send(void) { char *msg; if (!auth_debug_init) return; while (buffer_len(&auth_debug)) { msg = buffer_get_string(&auth_debug, NULL); packet_send_debug("%s", msg); free(msg); } } void auth_debug_reset(void) { if (auth_debug_init) buffer_clear(&auth_debug); else { buffer_init(&auth_debug); auth_debug_init = 1; } } struct passwd * fakepw(void) { static struct passwd fake; memset(&fake, 0, sizeof(fake)); fake.pw_name = "NOUSER"; fake.pw_passwd = "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK"; #ifdef HAVE_STRUCT_PASSWD_PW_GECOS fake.pw_gecos = "NOUSER"; #endif fake.pw_uid = privsep_pw == NULL ? (uid_t)-1 : privsep_pw->pw_uid; fake.pw_gid = privsep_pw == NULL ? (gid_t)-1 : privsep_pw->pw_gid; #ifdef HAVE_STRUCT_PASSWD_PW_CLASS fake.pw_class = ""; #endif fake.pw_dir = "/nonexist"; fake.pw_shell = "/nonexist"; return (&fake); } /* * Returns the remote DNS hostname as a string. The returned string must not * be freed. NB. this will usually trigger a DNS query the first time it is * called. * This function does additional checks on the hostname to mitigate some * attacks on legacy rhosts-style authentication. * XXX is RhostsRSAAuthentication vulnerable to these? * XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?) */ static char * remote_hostname(struct ssh *ssh) { struct sockaddr_storage from; socklen_t fromlen; struct addrinfo hints, *ai, *aitop; char name[NI_MAXHOST], ntop2[NI_MAXHOST]; const char *ntop = ssh_remote_ipaddr(ssh); /* Get IP address of client. */ fromlen = sizeof(from); memset(&from, 0, sizeof(from)); if (getpeername(ssh_packet_get_connection_in(ssh), (struct sockaddr *)&from, &fromlen) < 0) { debug("getpeername failed: %.100s", strerror(errno)); return strdup(ntop); } ipv64_normalise_mapped(&from, &fromlen); if (from.ss_family == AF_INET6) fromlen = sizeof(struct sockaddr_in6); debug3("Trying to reverse map address %.100s.", ntop); /* Map the IP address to a host name. */ if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name), NULL, 0, NI_NAMEREQD) != 0) { /* Host name not found. Use ip address. */ return strdup(ntop); } /* * if reverse lookup result looks like a numeric hostname, * someone is trying to trick us by PTR record like following: * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5 */ memset(&hints, 0, sizeof(hints)); hints.ai_socktype = SOCK_DGRAM; /*dummy*/ hints.ai_flags = AI_NUMERICHOST; if (getaddrinfo(name, NULL, &hints, &ai) == 0) { logit("Nasty PTR record \"%s\" is set up for %s, ignoring", name, ntop); freeaddrinfo(ai); return strdup(ntop); } /* Names are stored in lowercase. */ lowercase(name); /* * Map it back to an IP address and check that the given * address actually is an address of this host. This is * necessary because anyone with access to a name server can * define arbitrary names for an IP address. Mapping from * name to IP address can be trusted better (but can still be * fooled if the intruder has access to the name server of * the domain). */ memset(&hints, 0, sizeof(hints)); hints.ai_family = from.ss_family; hints.ai_socktype = SOCK_STREAM; if (getaddrinfo(name, NULL, &hints, &aitop) != 0) { logit("reverse mapping checking getaddrinfo for %.700s " "[%s] failed.", name, ntop); return strdup(ntop); } /* Look for the address from the list of addresses. */ for (ai = aitop; ai; ai = ai->ai_next) { if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2, sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 && (strcmp(ntop, ntop2) == 0)) break; } freeaddrinfo(aitop); /* If we reached the end of the list, the address was not there. */ if (ai == NULL) { /* Address not found for the host name. */ logit("Address %.100s maps to %.600s, but this does not " "map back to the address.", ntop, name); return strdup(ntop); } return strdup(name); } /* * Return the canonical name of the host in the other side of the current * connection. The host name is cached, so it is efficient to call this * several times. */ const char * auth_get_canonical_hostname(struct ssh *ssh, int use_dns) { static char *dnsname; if (!use_dns) return ssh_remote_ipaddr(ssh); else if (dnsname != NULL) return dnsname; else { dnsname = remote_hostname(ssh); return dnsname; } } diff --git a/crypto/openssh/auth1.c b/crypto/openssh/auth1.c index 71eb0c21b260..189954425ac2 100644 --- a/crypto/openssh/auth1.c +++ b/crypto/openssh/auth1.c @@ -1,447 +1,448 @@ /* $OpenBSD: auth1.c,v 1.82 2014/07/15 15:54:14 millert Exp $ */ /* * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland * All rights reserved * * As far as I am concerned, the code I have written for this software * can be used freely for any purpose. Any derived versions of this * software must be clearly marked as such, and if the derived work is * incompatible with the protocol description in the RFC file, it must be * called by a name other than "ssh" or "Secure Shell". */ #include "includes.h" #ifdef WITH_SSH1 #include #include #include #include #include #include #include "openbsd-compat/sys-queue.h" #include "xmalloc.h" #include "rsa.h" #include "ssh1.h" #include "packet.h" #include "buffer.h" #include "log.h" #include "misc.h" #include "servconf.h" #include "compat.h" #include "key.h" #include "hostfile.h" #include "auth.h" #include "channels.h" #include "session.h" #include "uidswap.h" #ifdef GSSAPI #include "ssh-gss.h" #endif #include "monitor_wrap.h" #include "buffer.h" #include "blacklist_client.h" /* import */ extern ServerOptions options; extern Buffer loginmsg; static int auth1_process_password(Authctxt *); static int auth1_process_rsa(Authctxt *); static int auth1_process_rhosts_rsa(Authctxt *); static int auth1_process_tis_challenge(Authctxt *); static int auth1_process_tis_response(Authctxt *); static char *client_user = NULL; /* Used to fill in remote user for PAM */ struct AuthMethod1 { int type; char *name; int *enabled; int (*method)(Authctxt *); }; const struct AuthMethod1 auth1_methods[] = { { SSH_CMSG_AUTH_PASSWORD, "password", &options.password_authentication, auth1_process_password }, { SSH_CMSG_AUTH_RSA, "rsa", &options.rsa_authentication, auth1_process_rsa }, { SSH_CMSG_AUTH_RHOSTS_RSA, "rhosts-rsa", &options.rhosts_rsa_authentication, auth1_process_rhosts_rsa }, { SSH_CMSG_AUTH_TIS, "challenge-response", &options.challenge_response_authentication, auth1_process_tis_challenge }, { SSH_CMSG_AUTH_TIS_RESPONSE, "challenge-response", &options.challenge_response_authentication, auth1_process_tis_response }, { -1, NULL, NULL, NULL} }; static const struct AuthMethod1 *lookup_authmethod1(int type) { int i; for (i = 0; auth1_methods[i].name != NULL; i++) if (auth1_methods[i].type == type) return (&(auth1_methods[i])); return (NULL); } static char * get_authname(int type) { const struct AuthMethod1 *a; static char buf[64]; if ((a = lookup_authmethod1(type)) != NULL) return (a->name); snprintf(buf, sizeof(buf), "bad-auth-msg-%d", type); return (buf); } /*ARGSUSED*/ static int auth1_process_password(Authctxt *authctxt) { int authenticated = 0; char *password; u_int dlen; /* * Read user password. It is in plain text, but was * transmitted over the encrypted channel so it is * not visible to an outside observer. */ password = packet_get_string(&dlen); packet_check_eom(); /* Try authentication with the password. */ authenticated = PRIVSEP(auth_password(authctxt, password)); explicit_bzero(password, dlen); free(password); return (authenticated); } /*ARGSUSED*/ static int auth1_process_rsa(Authctxt *authctxt) { int authenticated = 0; BIGNUM *n; /* RSA authentication requested. */ if ((n = BN_new()) == NULL) fatal("do_authloop: BN_new failed"); packet_get_bignum(n); packet_check_eom(); authenticated = auth_rsa(authctxt, n); BN_clear_free(n); return (authenticated); } /*ARGSUSED*/ static int auth1_process_rhosts_rsa(Authctxt *authctxt) { int keybits, authenticated = 0; u_int bits; Key *client_host_key; u_int ulen; /* * Get client user name. Note that we just have to * trust the client; root on the client machine can * claim to be any user. */ client_user = packet_get_cstring(&ulen); /* Get the client host key. */ client_host_key = key_new(KEY_RSA1); bits = packet_get_int(); packet_get_bignum(client_host_key->rsa->e); packet_get_bignum(client_host_key->rsa->n); keybits = BN_num_bits(client_host_key->rsa->n); if (keybits < 0 || bits != (u_int)keybits) { verbose("Warning: keysize mismatch for client_host_key: " "actual %d, announced %d", BN_num_bits(client_host_key->rsa->n), bits); } packet_check_eom(); authenticated = auth_rhosts_rsa(authctxt, client_user, client_host_key); key_free(client_host_key); auth_info(authctxt, "ruser %.100s", client_user); return (authenticated); } /*ARGSUSED*/ static int auth1_process_tis_challenge(Authctxt *authctxt) { char *challenge; if ((challenge = get_challenge(authctxt)) == NULL) return (0); debug("sending challenge '%s'", challenge); packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE); packet_put_cstring(challenge); free(challenge); packet_send(); packet_write_wait(); return (-1); } /*ARGSUSED*/ static int auth1_process_tis_response(Authctxt *authctxt) { int authenticated = 0; char *response; u_int dlen; response = packet_get_string(&dlen); packet_check_eom(); authenticated = verify_response(authctxt, response); explicit_bzero(response, dlen); free(response); return (authenticated); } /* * read packets, try to authenticate the user and * return only if authentication is successful */ static void do_authloop(Authctxt *authctxt) { int authenticated = 0; int prev = 0, type = 0; const struct AuthMethod1 *meth; debug("Attempting authentication for %s%.100s.", authctxt->valid ? "" : "invalid user ", authctxt->user); /* If the user has no password, accept authentication immediately. */ if (options.permit_empty_passwd && options.password_authentication && #ifdef KRB5 (!options.kerberos_authentication || options.kerberos_or_local_passwd) && #endif PRIVSEP(auth_password(authctxt, ""))) { #ifdef USE_PAM if (options.use_pam && (PRIVSEP(do_pam_account()))) #endif { auth_log(authctxt, 1, 0, "without authentication", NULL); return; } } /* Indicate that authentication is needed. */ packet_start(SSH_SMSG_FAILURE); packet_send(); packet_write_wait(); for (;;) { /* default to fail */ authenticated = 0; /* Get a packet from the client. */ prev = type; type = packet_read(); /* * If we started challenge-response authentication but the * next packet is not a response to our challenge, release * the resources allocated by get_challenge() (which would * normally have been released by verify_response() had we * received such a response) */ if (prev == SSH_CMSG_AUTH_TIS && type != SSH_CMSG_AUTH_TIS_RESPONSE) abandon_challenge_response(authctxt); if (authctxt->failures >= options.max_authtries) goto skip; if ((meth = lookup_authmethod1(type)) == NULL) { logit("Unknown message during authentication: " "type %d", type); goto skip; } if (!*(meth->enabled)) { verbose("%s authentication disabled.", meth->name); goto skip; } authenticated = meth->method(authctxt); if (authenticated == -1) continue; /* "postponed" */ #ifdef BSD_AUTH if (authctxt->as) { auth_close(authctxt->as); authctxt->as = NULL; } #endif if (!authctxt->valid && authenticated) fatal("INTERNAL ERROR: authenticated invalid user %s", authctxt->user); #ifdef _UNICOS if (authenticated && cray_access_denied(authctxt->user)) { authenticated = 0; fatal("Access denied for user %s.",authctxt->user); } #endif /* _UNICOS */ #ifndef HAVE_CYGWIN /* Special handling for root */ if (authenticated && authctxt->pw->pw_uid == 0 && !auth_root_allowed(meth->name)) { authenticated = 0; # ifdef SSH_AUDIT_EVENTS PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED)); # endif } #endif #ifdef USE_PAM if (options.use_pam && authenticated && !PRIVSEP(do_pam_account())) { char *msg; size_t len; - BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL); + BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL, "ssh"); error("Access denied for user %s by PAM account " "configuration", authctxt->user); len = buffer_len(&loginmsg); buffer_append(&loginmsg, "\0", 1); msg = buffer_ptr(&loginmsg); /* strip trailing newlines */ if (len > 0) while (len > 0 && msg[--len] == '\n') msg[len] = '\0'; else msg = "Access denied."; packet_disconnect("%s", msg); } #endif skip: /* Log before sending the reply */ auth_log(authctxt, authenticated, 0, get_authname(type), NULL); free(client_user); client_user = NULL; if (authenticated) return; + BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL, "ssh"); if (++authctxt->failures >= options.max_authtries) { #ifdef SSH_AUDIT_EVENTS PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES)); #endif auth_maxtries_exceeded(authctxt); } packet_start(SSH_SMSG_FAILURE); packet_send(); packet_write_wait(); } } /* * Performs authentication of an incoming connection. Session key has already * been exchanged and encryption is enabled. */ void do_authentication(Authctxt *authctxt) { u_int ulen; char *user, *style = NULL; /* Get the name of the user that we wish to log in as. */ packet_read_expect(SSH_CMSG_USER); /* Get the user name. */ user = packet_get_cstring(&ulen); packet_check_eom(); if ((style = strchr(user, ':')) != NULL) *style++ = '\0'; authctxt->user = user; authctxt->style = style; /* Verify that the user is a valid user. */ if ((authctxt->pw = PRIVSEP(getpwnamallow(user))) != NULL) authctxt->valid = 1; else { debug("do_authentication: invalid user %s", user); authctxt->pw = fakepw(); - BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL); + BLACKLIST_NOTIFY(BLACKLIST_BAD_USER, user); } /* Configuration may have changed as a result of Match */ if (options.num_auth_methods != 0) fatal("AuthenticationMethods is not supported with SSH " "protocol 1"); setproctitle("%s%s", authctxt->valid ? user : "unknown", use_privsep ? " [net]" : ""); #ifdef USE_PAM if (options.use_pam) PRIVSEP(start_pam(authctxt)); #endif /* * If we are not running as root, the user must have the same uid as * the server. */ #ifndef HAVE_CYGWIN if (!use_privsep && getuid() != 0 && authctxt->pw && authctxt->pw->pw_uid != getuid()) packet_disconnect("Cannot change user when server not running as root."); #endif /* * Loop until the user has been authenticated or the connection is * closed, do_authloop() returns only if authentication is successful */ do_authloop(authctxt); /* The user has been authenticated and accepted. */ packet_start(SSH_SMSG_SUCCESS); packet_send(); packet_write_wait(); } #endif /* WITH_SSH1 */ diff --git a/crypto/openssh/auth2.c b/crypto/openssh/auth2.c index 133b09a43ae0..b6695f79d0aa 100644 --- a/crypto/openssh/auth2.c +++ b/crypto/openssh/auth2.c @@ -1,648 +1,649 @@ /* $OpenBSD: auth2.c,v 1.136 2016/05/02 08:49:03 djm Exp $ */ /* * Copyright (c) 2000 Markus Friedl. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include "includes.h" __RCSID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include "atomicio.h" #include "xmalloc.h" #include "ssh2.h" #include "packet.h" #include "log.h" #include "buffer.h" #include "misc.h" #include "servconf.h" #include "compat.h" #include "key.h" #include "hostfile.h" #include "auth.h" #include "dispatch.h" #include "pathnames.h" #include "buffer.h" #include "blacklist_client.h" #ifdef GSSAPI #include "ssh-gss.h" #endif #include "monitor_wrap.h" /* import */ extern ServerOptions options; extern u_char *session_id2; extern u_int session_id2_len; extern Buffer loginmsg; /* methods */ extern Authmethod method_none; extern Authmethod method_pubkey; extern Authmethod method_passwd; extern Authmethod method_kbdint; extern Authmethod method_hostbased; #ifdef GSSAPI extern Authmethod method_gssapi; #endif Authmethod *authmethods[] = { &method_none, &method_pubkey, #ifdef GSSAPI &method_gssapi, #endif &method_passwd, &method_kbdint, &method_hostbased, NULL }; /* protocol */ static int input_service_request(int, u_int32_t, void *); static int input_userauth_request(int, u_int32_t, void *); /* helper */ static Authmethod *authmethod_lookup(Authctxt *, const char *); static char *authmethods_get(Authctxt *authctxt); #define MATCH_NONE 0 /* method or submethod mismatch */ #define MATCH_METHOD 1 /* method matches (no submethod specified) */ #define MATCH_BOTH 2 /* method and submethod match */ #define MATCH_PARTIAL 3 /* method matches, submethod can't be checked */ static int list_starts_with(const char *, const char *, const char *); char * auth2_read_banner(void) { struct stat st; char *banner = NULL; size_t len, n; int fd; if ((fd = open(options.banner, O_RDONLY)) == -1) return (NULL); if (fstat(fd, &st) == -1) { close(fd); return (NULL); } if (st.st_size <= 0 || st.st_size > 1*1024*1024) { close(fd); return (NULL); } len = (size_t)st.st_size; /* truncate */ banner = xmalloc(len + 1); n = atomicio(read, fd, banner, len); close(fd); if (n != len) { free(banner); return (NULL); } banner[n] = '\0'; return (banner); } void userauth_send_banner(const char *msg) { if (datafellows & SSH_BUG_BANNER) return; packet_start(SSH2_MSG_USERAUTH_BANNER); packet_put_cstring(msg); packet_put_cstring(""); /* language, unused */ packet_send(); debug("%s: sent", __func__); } static void userauth_banner(void) { char *banner = NULL; if (options.banner == NULL || (datafellows & SSH_BUG_BANNER) != 0) return; if ((banner = PRIVSEP(auth2_read_banner())) == NULL) goto done; userauth_send_banner(banner); done: free(banner); } /* * loop until authctxt->success == TRUE */ void do_authentication2(Authctxt *authctxt) { dispatch_init(&dispatch_protocol_error); dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request); dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt); } /*ARGSUSED*/ static int input_service_request(int type, u_int32_t seq, void *ctxt) { Authctxt *authctxt = ctxt; u_int len; int acceptit = 0; char *service = packet_get_cstring(&len); packet_check_eom(); if (authctxt == NULL) fatal("input_service_request: no authctxt"); if (strcmp(service, "ssh-userauth") == 0) { if (!authctxt->success) { acceptit = 1; /* now we can handle user-auth requests */ dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request); } } /* XXX all other service requests are denied */ if (acceptit) { packet_start(SSH2_MSG_SERVICE_ACCEPT); packet_put_cstring(service); packet_send(); packet_write_wait(); } else { debug("bad service request %s", service); packet_disconnect("bad service request %s", service); } free(service); return 0; } /*ARGSUSED*/ static int input_userauth_request(int type, u_int32_t seq, void *ctxt) { Authctxt *authctxt = ctxt; Authmethod *m = NULL; char *user, *service, *method, *style = NULL; int authenticated = 0; #ifdef HAVE_LOGIN_CAP struct ssh *ssh = active_state; /* XXX */ login_cap_t *lc; const char *from_host, *from_ip; #endif if (authctxt == NULL) fatal("input_userauth_request: no authctxt"); user = packet_get_cstring(NULL); service = packet_get_cstring(NULL); method = packet_get_cstring(NULL); debug("userauth-request for user %s service %s method %s", user, service, method); debug("attempt %d failures %d", authctxt->attempt, authctxt->failures); if ((style = strchr(user, ':')) != NULL) *style++ = 0; if (authctxt->attempt++ == 0) { /* setup auth context */ authctxt->pw = PRIVSEP(getpwnamallow(user)); authctxt->user = xstrdup(user); if (authctxt->pw && strcmp(service, "ssh-connection")==0) { authctxt->valid = 1; debug2("input_userauth_request: setting up authctxt for %s", user); } else { logit("input_userauth_request: invalid user %s", user); authctxt->pw = fakepw(); - BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL); #ifdef SSH_AUDIT_EVENTS PRIVSEP(audit_event(SSH_INVALID_USER)); #endif } #ifdef USE_PAM if (options.use_pam) PRIVSEP(start_pam(authctxt)); #endif setproctitle("%s%s", authctxt->valid ? user : "unknown", use_privsep ? " [net]" : ""); authctxt->service = xstrdup(service); authctxt->style = style ? xstrdup(style) : NULL; if (use_privsep) mm_inform_authserv(service, style); userauth_banner(); if (auth2_setup_methods_lists(authctxt) != 0) packet_disconnect("no authentication methods enabled"); } else if (strcmp(user, authctxt->user) != 0 || strcmp(service, authctxt->service) != 0) { packet_disconnect("Change of username or service not allowed: " "(%s,%s) -> (%s,%s)", authctxt->user, authctxt->service, user, service); } #ifdef HAVE_LOGIN_CAP if (authctxt->pw != NULL && (lc = login_getpwclass(authctxt->pw)) != NULL) { logit("user %s login class %s", authctxt->pw->pw_name, authctxt->pw->pw_class); from_host = auth_get_canonical_hostname(ssh, options.use_dns); from_ip = ssh_remote_ipaddr(ssh); if (!auth_hostok(lc, from_host, from_ip)) { logit("Denied connection for %.200s from %.200s [%.200s].", authctxt->pw->pw_name, from_host, from_ip); packet_disconnect("Sorry, you are not allowed to connect."); } if (!auth_timeok(lc, time(NULL))) { logit("LOGIN %.200s REFUSED (TIME) FROM %.200s", authctxt->pw->pw_name, from_host); packet_disconnect("Logins not available right now."); } login_close(lc); } #endif /* HAVE_LOGIN_CAP */ /* reset state */ auth2_challenge_stop(authctxt); #ifdef GSSAPI /* XXX move to auth2_gssapi_stop() */ dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL); dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL); #endif authctxt->postponed = 0; authctxt->server_caused_failure = 0; /* try to authenticate user */ m = authmethod_lookup(authctxt, method); if (m != NULL && authctxt->failures < options.max_authtries) { debug2("input_userauth_request: try method %s", method); authenticated = m->userauth(authctxt); } userauth_finish(authctxt, authenticated, method, NULL); free(service); free(user); free(method); return 0; } void userauth_finish(Authctxt *authctxt, int authenticated, const char *method, const char *submethod) { char *methods; int partial = 0; if (!authctxt->valid && authenticated) fatal("INTERNAL ERROR: authenticated invalid user %s", authctxt->user); if (authenticated && authctxt->postponed) fatal("INTERNAL ERROR: authenticated and postponed"); /* Special handling for root */ if (authenticated && authctxt->pw->pw_uid == 0 && !auth_root_allowed(method)) { authenticated = 0; #ifdef SSH_AUDIT_EVENTS PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED)); #endif } if (authenticated && options.num_auth_methods != 0) { if (!auth2_update_methods_lists(authctxt, method, submethod)) { authenticated = 0; partial = 1; } } /* Log before sending the reply */ auth_log(authctxt, authenticated, partial, method, submethod); if (authctxt->postponed) return; #ifdef USE_PAM if (options.use_pam && authenticated) { if (!PRIVSEP(do_pam_account())) { /* if PAM returned a message, send it to the user */ if (buffer_len(&loginmsg) > 0) { buffer_append(&loginmsg, "\0", 1); userauth_send_banner(buffer_ptr(&loginmsg)); packet_write_wait(); } fatal("Access denied for user %s by PAM account " "configuration", authctxt->user); } } #endif #ifdef _UNICOS if (authenticated && cray_access_denied(authctxt->user)) { authenticated = 0; fatal("Access denied for user %s.", authctxt->user); } #endif /* _UNICOS */ if (authenticated == 1) { /* turn off userauth */ dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore); packet_start(SSH2_MSG_USERAUTH_SUCCESS); packet_send(); packet_write_wait(); /* now we can break out */ authctxt->success = 1; } else { /* Allow initial try of "none" auth without failure penalty */ if (!partial && !authctxt->server_caused_failure && - (authctxt->attempt > 1 || strcmp(method, "none") != 0)) + (authctxt->attempt > 1 || strcmp(method, "none") != 0)) { authctxt->failures++; + BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL, "ssh"); + } if (authctxt->failures >= options.max_authtries) { #ifdef SSH_AUDIT_EVENTS PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES)); #endif auth_maxtries_exceeded(authctxt); } methods = authmethods_get(authctxt); debug3("%s: failure partial=%d next methods=\"%s\"", __func__, partial, methods); packet_start(SSH2_MSG_USERAUTH_FAILURE); packet_put_cstring(methods); packet_put_char(partial); packet_send(); packet_write_wait(); free(methods); } } /* * Checks whether method is allowed by at least one AuthenticationMethods * methods list. Returns 1 if allowed, or no methods lists configured. * 0 otherwise. */ int auth2_method_allowed(Authctxt *authctxt, const char *method, const char *submethod) { u_int i; /* * NB. authctxt->num_auth_methods might be zero as a result of * auth2_setup_methods_lists(), so check the configuration. */ if (options.num_auth_methods == 0) return 1; for (i = 0; i < authctxt->num_auth_methods; i++) { if (list_starts_with(authctxt->auth_methods[i], method, submethod) != MATCH_NONE) return 1; } return 0; } static char * authmethods_get(Authctxt *authctxt) { Buffer b; char *list; u_int i; buffer_init(&b); for (i = 0; authmethods[i] != NULL; i++) { if (strcmp(authmethods[i]->name, "none") == 0) continue; if (authmethods[i]->enabled == NULL || *(authmethods[i]->enabled) == 0) continue; if (!auth2_method_allowed(authctxt, authmethods[i]->name, NULL)) continue; if (buffer_len(&b) > 0) buffer_append(&b, ",", 1); buffer_append(&b, authmethods[i]->name, strlen(authmethods[i]->name)); } if ((list = sshbuf_dup_string(&b)) == NULL) fatal("%s: sshbuf_dup_string failed", __func__); buffer_free(&b); return list; } static Authmethod * authmethod_lookup(Authctxt *authctxt, const char *name) { int i; if (name != NULL) for (i = 0; authmethods[i] != NULL; i++) if (authmethods[i]->enabled != NULL && *(authmethods[i]->enabled) != 0 && strcmp(name, authmethods[i]->name) == 0 && auth2_method_allowed(authctxt, authmethods[i]->name, NULL)) return authmethods[i]; debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); return NULL; } /* * Check a comma-separated list of methods for validity. Is need_enable is * non-zero, then also require that the methods are enabled. * Returns 0 on success or -1 if the methods list is invalid. */ int auth2_methods_valid(const char *_methods, int need_enable) { char *methods, *omethods, *method, *p; u_int i, found; int ret = -1; if (*_methods == '\0') { error("empty authentication method list"); return -1; } omethods = methods = xstrdup(_methods); while ((method = strsep(&methods, ",")) != NULL) { for (found = i = 0; !found && authmethods[i] != NULL; i++) { if ((p = strchr(method, ':')) != NULL) *p = '\0'; if (strcmp(method, authmethods[i]->name) != 0) continue; if (need_enable) { if (authmethods[i]->enabled == NULL || *(authmethods[i]->enabled) == 0) { error("Disabled method \"%s\" in " "AuthenticationMethods list \"%s\"", method, _methods); goto out; } } found = 1; break; } if (!found) { error("Unknown authentication method \"%s\" in list", method); goto out; } } ret = 0; out: free(omethods); return ret; } /* * Prune the AuthenticationMethods supplied in the configuration, removing * any methods lists that include disabled methods. Note that this might * leave authctxt->num_auth_methods == 0, even when multiple required auth * has been requested. For this reason, all tests for whether multiple is * enabled should consult options.num_auth_methods directly. */ int auth2_setup_methods_lists(Authctxt *authctxt) { u_int i; if (options.num_auth_methods == 0) return 0; debug3("%s: checking methods", __func__); authctxt->auth_methods = xcalloc(options.num_auth_methods, sizeof(*authctxt->auth_methods)); authctxt->num_auth_methods = 0; for (i = 0; i < options.num_auth_methods; i++) { if (auth2_methods_valid(options.auth_methods[i], 1) != 0) { logit("Authentication methods list \"%s\" contains " "disabled method, skipping", options.auth_methods[i]); continue; } debug("authentication methods list %d: %s", authctxt->num_auth_methods, options.auth_methods[i]); authctxt->auth_methods[authctxt->num_auth_methods++] = xstrdup(options.auth_methods[i]); } if (authctxt->num_auth_methods == 0) { error("No AuthenticationMethods left after eliminating " "disabled methods"); return -1; } return 0; } static int list_starts_with(const char *methods, const char *method, const char *submethod) { size_t l = strlen(method); int match; const char *p; if (strncmp(methods, method, l) != 0) return MATCH_NONE; p = methods + l; match = MATCH_METHOD; if (*p == ':') { if (!submethod) return MATCH_PARTIAL; l = strlen(submethod); p += 1; if (strncmp(submethod, p, l)) return MATCH_NONE; p += l; match = MATCH_BOTH; } if (*p != ',' && *p != '\0') return MATCH_NONE; return match; } /* * Remove method from the start of a comma-separated list of methods. * Returns 0 if the list of methods did not start with that method or 1 * if it did. */ static int remove_method(char **methods, const char *method, const char *submethod) { char *omethods = *methods, *p; size_t l = strlen(method); int match; match = list_starts_with(omethods, method, submethod); if (match != MATCH_METHOD && match != MATCH_BOTH) return 0; p = omethods + l; if (submethod && match == MATCH_BOTH) p += 1 + strlen(submethod); /* include colon */ if (*p == ',') p++; *methods = xstrdup(p); free(omethods); return 1; } /* * Called after successful authentication. Will remove the successful method * from the start of each list in which it occurs. If it was the last method * in any list, then authentication is deemed successful. * Returns 1 if the method completed any authentication list or 0 otherwise. */ int auth2_update_methods_lists(Authctxt *authctxt, const char *method, const char *submethod) { u_int i, found = 0; debug3("%s: updating methods list after \"%s\"", __func__, method); for (i = 0; i < authctxt->num_auth_methods; i++) { if (!remove_method(&(authctxt->auth_methods[i]), method, submethod)) continue; found = 1; if (*authctxt->auth_methods[i] == '\0') { debug2("authentication methods list %d complete", i); return 1; } debug3("authentication methods list %d remaining: \"%s\"", i, authctxt->auth_methods[i]); } /* This should not happen, but would be bad if it did */ if (!found) fatal("%s: method not in AuthenticationMethods", __func__); return 0; } diff --git a/crypto/openssh/blacklist.c b/crypto/openssh/blacklist.c index 4c9d91dec164..b4f5d3e128c1 100644 --- a/crypto/openssh/blacklist.c +++ b/crypto/openssh/blacklist.c @@ -1,97 +1,97 @@ /*- * Copyright (c) 2015 The NetBSD Foundation, Inc. * Copyright (c) 2016 The FreeBSD Foundation, Inc. * All rights reserved. * * Portions of this software were developed by Kurt Lidl * under sponsorship from the FreeBSD Foundation. * * This code is derived from software contributed to The NetBSD Foundation * by Christos Zoulas. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #include "includes.h" #include #include #include #include #include #include #include #include "ssh.h" #include "packet.h" #include "log.h" #include "misc.h" #include "servconf.h" -#include "blacklist_client.h" #include +#include "blacklist_client.h" static struct blacklist *blstate = NULL; /* import */ extern ServerOptions options; /* internal definition from bl.h */ struct blacklist *bl_create(bool, char *, void (*)(int, const char *, va_list)); /* impedence match vsyslog() to sshd's internal logging levels */ void im_log(int priority, const char *message, va_list args) { LogLevel imlevel; switch (priority) { case LOG_ERR: imlevel = SYSLOG_LEVEL_ERROR; break; case LOG_DEBUG: imlevel = SYSLOG_LEVEL_DEBUG1; break; case LOG_INFO: imlevel = SYSLOG_LEVEL_INFO; break; default: imlevel = SYSLOG_LEVEL_DEBUG2; } do_log(imlevel, message, args); } void blacklist_init(void) { if (options.use_blacklist) blstate = bl_create(false, NULL, im_log); } void -blacklist_notify(int action) +blacklist_notify(int action, const char *msg) { if (blstate != NULL && packet_connection_is_on_socket()) (void)blacklist_r(blstate, action, - packet_get_connection_in(), "ssh"); + packet_get_connection_in(), msg); } diff --git a/crypto/openssh/blacklist_client.h b/crypto/openssh/blacklist_client.h index 9479bb27be46..af5a2a6d3c1d 100644 --- a/crypto/openssh/blacklist_client.h +++ b/crypto/openssh/blacklist_client.h @@ -1,57 +1,61 @@ /*- * Copyright (c) 2015 The NetBSD Foundation, Inc. * Copyright (c) 2016 The FreeBSD Foundation, Inc. * All rights reserved. * * Portions of this software were developed by Kurt Lidl * under sponsorship from the FreeBSD Foundation. * * This code is derived from software contributed to The NetBSD Foundation * by Christos Zoulas. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #ifndef BLACKLIST_CLIENT_H #define BLACKLIST_CLIENT_H +#ifndef BLACKLIST_API_ENUM enum { BLACKLIST_AUTH_OK = 0, - BLACKLIST_AUTH_FAIL + BLACKLIST_AUTH_FAIL, + BLACKLIST_ABUSIVE_BEHAVIOR, + BLACKLIST_BAD_USER }; +#endif #ifdef USE_BLACKLIST void blacklist_init(void); -void blacklist_notify(int); +void blacklist_notify(int, const char *); #define BLACKLIST_INIT() blacklist_init() -#define BLACKLIST_NOTIFY(x) blacklist_notify(x) +#define BLACKLIST_NOTIFY(x,msg) blacklist_notify(x,msg) #else #define BLACKLIST_INIT() -#define BLACKLIST_NOTIFY(x) +#define BLACKLIST_NOTIFY(x,msg) #endif #endif /* BLACKLIST_CLIENT_H */ diff --git a/crypto/openssh/packet.c b/crypto/openssh/packet.c index 5db5828749a4..9ef5778baffc 100644 --- a/crypto/openssh/packet.c +++ b/crypto/openssh/packet.c @@ -1,3029 +1,3029 @@ /* $OpenBSD: packet.c,v 1.243 2016/10/11 21:47:45 djm Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland * All rights reserved * This file contains code implementing the packet protocol and communication * with the other side. This same code is used both on client and server side. * * As far as I am concerned, the code I have written for this software * can be used freely for any purpose. Any derived versions of this * software must be clearly marked as such, and if the derived work is * incompatible with the protocol description in the RFC file, it must be * called by a name other than "ssh" or "Secure Shell". * * * SSH2 packet format added by Markus Friedl. * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include "includes.h" __RCSID("$FreeBSD$"); #include #include "openbsd-compat/sys-queue.h" #include #ifdef HAVE_SYS_TIME_H # include #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "buffer.h" /* typedefs XXX */ #include "key.h" /* typedefs XXX */ #include "xmalloc.h" #include "crc32.h" #include "deattack.h" #include "compat.h" #include "ssh1.h" #include "ssh2.h" #include "cipher.h" #include "sshkey.h" #include "kex.h" #include "digest.h" #include "mac.h" #include "log.h" #include "canohost.h" #include "misc.h" #include "channels.h" #include "ssh.h" #include "packet.h" #include "ssherr.h" #include "sshbuf.h" #include "blacklist_client.h" #ifdef PACKET_DEBUG #define DBG(x) x #else #define DBG(x) #endif #define PACKET_MAX_SIZE (256 * 1024) struct packet_state { u_int32_t seqnr; u_int32_t packets; u_int64_t blocks; u_int64_t bytes; }; struct packet { TAILQ_ENTRY(packet) next; u_char type; struct sshbuf *payload; }; struct session_state { /* * This variable contains the file descriptors used for * communicating with the other side. connection_in is used for * reading; connection_out for writing. These can be the same * descriptor, in which case it is assumed to be a socket. */ int connection_in; int connection_out; /* Protocol flags for the remote side. */ u_int remote_protocol_flags; /* Encryption context for receiving data. Only used for decryption. */ struct sshcipher_ctx *receive_context; /* Encryption context for sending data. Only used for encryption. */ struct sshcipher_ctx *send_context; /* Buffer for raw input data from the socket. */ struct sshbuf *input; /* Buffer for raw output data going to the socket. */ struct sshbuf *output; /* Buffer for the partial outgoing packet being constructed. */ struct sshbuf *outgoing_packet; /* Buffer for the incoming packet currently being processed. */ struct sshbuf *incoming_packet; /* Scratch buffer for packet compression/decompression. */ struct sshbuf *compression_buffer; /* Incoming/outgoing compression dictionaries */ z_stream compression_in_stream; z_stream compression_out_stream; int compression_in_started; int compression_out_started; int compression_in_failures; int compression_out_failures; /* * Flag indicating whether packet compression/decompression is * enabled. */ int packet_compression; /* default maximum packet size */ u_int max_packet_size; /* Flag indicating whether this module has been initialized. */ int initialized; /* Set to true if the connection is interactive. */ int interactive_mode; /* Set to true if we are the server side. */ int server_side; /* Set to true if we are authenticated. */ int after_authentication; int keep_alive_timeouts; /* The maximum time that we will wait to send or receive a packet */ int packet_timeout_ms; /* Session key information for Encryption and MAC */ struct newkeys *newkeys[MODE_MAX]; struct packet_state p_read, p_send; /* Volume-based rekeying */ u_int64_t max_blocks_in, max_blocks_out, rekey_limit; /* Time-based rekeying */ u_int32_t rekey_interval; /* how often in seconds */ time_t rekey_time; /* time of last rekeying */ /* Session key for protocol v1 */ u_char ssh1_key[SSH_SESSION_KEY_LENGTH]; u_int ssh1_keylen; /* roundup current message to extra_pad bytes */ u_char extra_pad; /* XXX discard incoming data after MAC error */ u_int packet_discard; size_t packet_discard_mac_already; struct sshmac *packet_discard_mac; /* Used in packet_read_poll2() */ u_int packlen; /* Used in packet_send2 */ int rekeying; /* Used in ssh_packet_send_mux() */ int mux; /* Used in packet_set_interactive */ int set_interactive_called; /* Used in packet_set_maxsize */ int set_maxsize_called; /* One-off warning about weak ciphers */ int cipher_warning_done; /* SSH1 CRC compensation attack detector */ struct deattack_ctx deattack; /* Hook for fuzzing inbound packets */ ssh_packet_hook_fn *hook_in; void *hook_in_ctx; TAILQ_HEAD(, packet) outgoing; }; struct ssh * ssh_alloc_session_state(void) { struct ssh *ssh = NULL; struct session_state *state = NULL; if ((ssh = calloc(1, sizeof(*ssh))) == NULL || (state = calloc(1, sizeof(*state))) == NULL || (state->input = sshbuf_new()) == NULL || (state->output = sshbuf_new()) == NULL || (state->outgoing_packet = sshbuf_new()) == NULL || (state->incoming_packet = sshbuf_new()) == NULL) goto fail; TAILQ_INIT(&state->outgoing); TAILQ_INIT(&ssh->private_keys); TAILQ_INIT(&ssh->public_keys); state->connection_in = -1; state->connection_out = -1; state->max_packet_size = 32768; state->packet_timeout_ms = -1; state->p_send.packets = state->p_read.packets = 0; state->initialized = 1; /* * ssh_packet_send2() needs to queue packets until * we've done the initial key exchange. */ state->rekeying = 1; ssh->state = state; return ssh; fail: if (state) { sshbuf_free(state->input); sshbuf_free(state->output); sshbuf_free(state->incoming_packet); sshbuf_free(state->outgoing_packet); free(state); } free(ssh); return NULL; } void ssh_packet_set_input_hook(struct ssh *ssh, ssh_packet_hook_fn *hook, void *ctx) { ssh->state->hook_in = hook; ssh->state->hook_in_ctx = ctx; } /* Returns nonzero if rekeying is in progress */ int ssh_packet_is_rekeying(struct ssh *ssh) { return compat20 && (ssh->state->rekeying || (ssh->kex != NULL && ssh->kex->done == 0)); } /* * Sets the descriptors used for communication. Disables encryption until * packet_set_encryption_key is called. */ struct ssh * ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out) { struct session_state *state; const struct sshcipher *none = cipher_by_name("none"); int r; if (none == NULL) { error("%s: cannot load cipher 'none'", __func__); return NULL; } if (ssh == NULL) ssh = ssh_alloc_session_state(); if (ssh == NULL) { error("%s: cound not allocate state", __func__); return NULL; } state = ssh->state; state->connection_in = fd_in; state->connection_out = fd_out; if ((r = cipher_init(&state->send_context, none, (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 || (r = cipher_init(&state->receive_context, none, (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0) { error("%s: cipher_init failed: %s", __func__, ssh_err(r)); free(ssh); /* XXX need ssh_free_session_state? */ return NULL; } state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL; deattack_init(&state->deattack); /* * Cache the IP address of the remote connection for use in error * messages that might be generated after the connection has closed. */ (void)ssh_remote_ipaddr(ssh); return ssh; } void ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count) { struct session_state *state = ssh->state; if (timeout <= 0 || count <= 0) { state->packet_timeout_ms = -1; return; } if ((INT_MAX / 1000) / count < timeout) state->packet_timeout_ms = INT_MAX; else state->packet_timeout_ms = timeout * count * 1000; } void ssh_packet_set_mux(struct ssh *ssh) { ssh->state->mux = 1; ssh->state->rekeying = 0; } int ssh_packet_get_mux(struct ssh *ssh) { return ssh->state->mux; } int ssh_packet_stop_discard(struct ssh *ssh) { struct session_state *state = ssh->state; int r; if (state->packet_discard_mac) { char buf[1024]; size_t dlen = PACKET_MAX_SIZE; if (dlen > state->packet_discard_mac_already) dlen -= state->packet_discard_mac_already; memset(buf, 'a', sizeof(buf)); while (sshbuf_len(state->incoming_packet) < dlen) if ((r = sshbuf_put(state->incoming_packet, buf, sizeof(buf))) != 0) return r; (void) mac_compute(state->packet_discard_mac, state->p_read.seqnr, sshbuf_ptr(state->incoming_packet), dlen, NULL, 0); } logit("Finished discarding for %.200s port %d", ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); return SSH_ERR_MAC_INVALID; } static int ssh_packet_start_discard(struct ssh *ssh, struct sshenc *enc, struct sshmac *mac, size_t mac_already, u_int discard) { struct session_state *state = ssh->state; int r; if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) { if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) return r; return SSH_ERR_MAC_INVALID; } /* * Record number of bytes over which the mac has already * been computed in order to minimize timing attacks. */ if (mac && mac->enabled) { state->packet_discard_mac = mac; state->packet_discard_mac_already = mac_already; } if (sshbuf_len(state->input) >= discard) return ssh_packet_stop_discard(ssh); state->packet_discard = discard - sshbuf_len(state->input); return 0; } /* Returns 1 if remote host is connected via socket, 0 if not. */ int ssh_packet_connection_is_on_socket(struct ssh *ssh) { struct session_state *state = ssh->state; struct sockaddr_storage from, to; socklen_t fromlen, tolen; if (state->connection_in == -1 || state->connection_out == -1) return 0; /* filedescriptors in and out are the same, so it's a socket */ if (state->connection_in == state->connection_out) return 1; fromlen = sizeof(from); memset(&from, 0, sizeof(from)); if (getpeername(state->connection_in, (struct sockaddr *)&from, &fromlen) < 0) return 0; tolen = sizeof(to); memset(&to, 0, sizeof(to)); if (getpeername(state->connection_out, (struct sockaddr *)&to, &tolen) < 0) return 0; if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0) return 0; if (from.ss_family != AF_INET && from.ss_family != AF_INET6) return 0; return 1; } void ssh_packet_get_bytes(struct ssh *ssh, u_int64_t *ibytes, u_int64_t *obytes) { if (ibytes) *ibytes = ssh->state->p_read.bytes; if (obytes) *obytes = ssh->state->p_send.bytes; } int ssh_packet_connection_af(struct ssh *ssh) { struct sockaddr_storage to; socklen_t tolen = sizeof(to); memset(&to, 0, sizeof(to)); if (getsockname(ssh->state->connection_out, (struct sockaddr *)&to, &tolen) < 0) return 0; #ifdef IPV4_IN_IPV6 if (to.ss_family == AF_INET6 && IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr)) return AF_INET; #endif return to.ss_family; } /* Sets the connection into non-blocking mode. */ void ssh_packet_set_nonblocking(struct ssh *ssh) { /* Set the socket into non-blocking mode. */ set_nonblock(ssh->state->connection_in); if (ssh->state->connection_out != ssh->state->connection_in) set_nonblock(ssh->state->connection_out); } /* Returns the socket used for reading. */ int ssh_packet_get_connection_in(struct ssh *ssh) { return ssh->state->connection_in; } /* Returns the descriptor used for writing. */ int ssh_packet_get_connection_out(struct ssh *ssh) { return ssh->state->connection_out; } /* * Returns the IP-address of the remote host as a string. The returned * string must not be freed. */ const char * ssh_remote_ipaddr(struct ssh *ssh) { const int sock = ssh->state->connection_in; /* Check whether we have cached the ipaddr. */ if (ssh->remote_ipaddr == NULL) { if (ssh_packet_connection_is_on_socket(ssh)) { ssh->remote_ipaddr = get_peer_ipaddr(sock); ssh->remote_port = get_peer_port(sock); ssh->local_ipaddr = get_local_ipaddr(sock); ssh->local_port = get_local_port(sock); } else { ssh->remote_ipaddr = strdup("UNKNOWN"); ssh->remote_port = 65535; ssh->local_ipaddr = strdup("UNKNOWN"); ssh->local_port = 65535; } } return ssh->remote_ipaddr; } /* Returns the port number of the remote host. */ int ssh_remote_port(struct ssh *ssh) { (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ return ssh->remote_port; } /* * Returns the IP-address of the local host as a string. The returned * string must not be freed. */ const char * ssh_local_ipaddr(struct ssh *ssh) { (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ return ssh->local_ipaddr; } /* Returns the port number of the local host. */ int ssh_local_port(struct ssh *ssh) { (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ return ssh->local_port; } /* Closes the connection and clears and frees internal data structures. */ void ssh_packet_close(struct ssh *ssh) { struct session_state *state = ssh->state; u_int mode; if (!state->initialized) return; state->initialized = 0; if (state->connection_in == state->connection_out) { shutdown(state->connection_out, SHUT_RDWR); close(state->connection_out); } else { close(state->connection_in); close(state->connection_out); } sshbuf_free(state->input); sshbuf_free(state->output); sshbuf_free(state->outgoing_packet); sshbuf_free(state->incoming_packet); for (mode = 0; mode < MODE_MAX; mode++) kex_free_newkeys(state->newkeys[mode]); if (state->compression_buffer) { sshbuf_free(state->compression_buffer); if (state->compression_out_started) { z_streamp stream = &state->compression_out_stream; debug("compress outgoing: " "raw data %llu, compressed %llu, factor %.2f", (unsigned long long)stream->total_in, (unsigned long long)stream->total_out, stream->total_in == 0 ? 0.0 : (double) stream->total_out / stream->total_in); if (state->compression_out_failures == 0) deflateEnd(stream); } if (state->compression_in_started) { z_streamp stream = &state->compression_out_stream; debug("compress incoming: " "raw data %llu, compressed %llu, factor %.2f", (unsigned long long)stream->total_out, (unsigned long long)stream->total_in, stream->total_out == 0 ? 0.0 : (double) stream->total_in / stream->total_out); if (state->compression_in_failures == 0) inflateEnd(stream); } } cipher_free(state->send_context); cipher_free(state->receive_context); state->send_context = state->receive_context = NULL; free(ssh->remote_ipaddr); ssh->remote_ipaddr = NULL; free(ssh->state); ssh->state = NULL; } /* Sets remote side protocol flags. */ void ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags) { ssh->state->remote_protocol_flags = protocol_flags; } /* Returns the remote protocol flags set earlier by the above function. */ u_int ssh_packet_get_protocol_flags(struct ssh *ssh) { return ssh->state->remote_protocol_flags; } /* * Starts packet compression from the next packet on in both directions. * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. */ static int ssh_packet_init_compression(struct ssh *ssh) { if (!ssh->state->compression_buffer && ((ssh->state->compression_buffer = sshbuf_new()) == NULL)) return SSH_ERR_ALLOC_FAIL; return 0; } static int start_compression_out(struct ssh *ssh, int level) { if (level < 1 || level > 9) return SSH_ERR_INVALID_ARGUMENT; debug("Enabling compression at level %d.", level); if (ssh->state->compression_out_started == 1) deflateEnd(&ssh->state->compression_out_stream); switch (deflateInit(&ssh->state->compression_out_stream, level)) { case Z_OK: ssh->state->compression_out_started = 1; break; case Z_MEM_ERROR: return SSH_ERR_ALLOC_FAIL; default: return SSH_ERR_INTERNAL_ERROR; } return 0; } static int start_compression_in(struct ssh *ssh) { if (ssh->state->compression_in_started == 1) inflateEnd(&ssh->state->compression_in_stream); switch (inflateInit(&ssh->state->compression_in_stream)) { case Z_OK: ssh->state->compression_in_started = 1; break; case Z_MEM_ERROR: return SSH_ERR_ALLOC_FAIL; default: return SSH_ERR_INTERNAL_ERROR; } return 0; } int ssh_packet_start_compression(struct ssh *ssh, int level) { int r; if (ssh->state->packet_compression && !compat20) return SSH_ERR_INTERNAL_ERROR; ssh->state->packet_compression = 1; if ((r = ssh_packet_init_compression(ssh)) != 0 || (r = start_compression_in(ssh)) != 0 || (r = start_compression_out(ssh, level)) != 0) return r; return 0; } /* XXX remove need for separate compression buffer */ static int compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) { u_char buf[4096]; int r, status; if (ssh->state->compression_out_started != 1) return SSH_ERR_INTERNAL_ERROR; /* This case is not handled below. */ if (sshbuf_len(in) == 0) return 0; /* Input is the contents of the input buffer. */ if ((ssh->state->compression_out_stream.next_in = sshbuf_mutable_ptr(in)) == NULL) return SSH_ERR_INTERNAL_ERROR; ssh->state->compression_out_stream.avail_in = sshbuf_len(in); /* Loop compressing until deflate() returns with avail_out != 0. */ do { /* Set up fixed-size output buffer. */ ssh->state->compression_out_stream.next_out = buf; ssh->state->compression_out_stream.avail_out = sizeof(buf); /* Compress as much data into the buffer as possible. */ status = deflate(&ssh->state->compression_out_stream, Z_PARTIAL_FLUSH); switch (status) { case Z_MEM_ERROR: return SSH_ERR_ALLOC_FAIL; case Z_OK: /* Append compressed data to output_buffer. */ if ((r = sshbuf_put(out, buf, sizeof(buf) - ssh->state->compression_out_stream.avail_out)) != 0) return r; break; case Z_STREAM_ERROR: default: ssh->state->compression_out_failures++; return SSH_ERR_INVALID_FORMAT; } } while (ssh->state->compression_out_stream.avail_out == 0); return 0; } static int uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) { u_char buf[4096]; int r, status; if (ssh->state->compression_in_started != 1) return SSH_ERR_INTERNAL_ERROR; if ((ssh->state->compression_in_stream.next_in = sshbuf_mutable_ptr(in)) == NULL) return SSH_ERR_INTERNAL_ERROR; ssh->state->compression_in_stream.avail_in = sshbuf_len(in); for (;;) { /* Set up fixed-size output buffer. */ ssh->state->compression_in_stream.next_out = buf; ssh->state->compression_in_stream.avail_out = sizeof(buf); status = inflate(&ssh->state->compression_in_stream, Z_PARTIAL_FLUSH); switch (status) { case Z_OK: if ((r = sshbuf_put(out, buf, sizeof(buf) - ssh->state->compression_in_stream.avail_out)) != 0) return r; break; case Z_BUF_ERROR: /* * Comments in zlib.h say that we should keep calling * inflate() until we get an error. This appears to * be the error that we get. */ return 0; case Z_DATA_ERROR: return SSH_ERR_INVALID_FORMAT; case Z_MEM_ERROR: return SSH_ERR_ALLOC_FAIL; case Z_STREAM_ERROR: default: ssh->state->compression_in_failures++; return SSH_ERR_INTERNAL_ERROR; } } /* NOTREACHED */ } /* * Causes any further packets to be encrypted using the given key. The same * key is used for both sending and reception. However, both directions are * encrypted independently of each other. */ void ssh_packet_set_encryption_key(struct ssh *ssh, const u_char *key, u_int keylen, int number) { #ifndef WITH_SSH1 fatal("no SSH protocol 1 support"); #else /* WITH_SSH1 */ struct session_state *state = ssh->state; const struct sshcipher *cipher = cipher_by_number(number); int r; const char *wmsg; if (cipher == NULL) fatal("%s: unknown cipher number %d", __func__, number); if (keylen < 20) fatal("%s: keylen too small: %d", __func__, keylen); if (keylen > SSH_SESSION_KEY_LENGTH) fatal("%s: keylen too big: %d", __func__, keylen); memcpy(state->ssh1_key, key, keylen); state->ssh1_keylen = keylen; if ((r = cipher_init(&state->send_context, cipher, key, keylen, NULL, 0, CIPHER_ENCRYPT)) != 0 || (r = cipher_init(&state->receive_context, cipher, key, keylen, NULL, 0, CIPHER_DECRYPT) != 0)) fatal("%s: cipher_init failed: %s", __func__, ssh_err(r)); if (!state->cipher_warning_done && ((wmsg = cipher_warning_message(state->send_context)) != NULL || (wmsg = cipher_warning_message(state->send_context)) != NULL)) { error("Warning: %s", wmsg); state->cipher_warning_done = 1; } #endif /* WITH_SSH1 */ } /* * Finalizes and sends the packet. If the encryption key has been set, * encrypts the packet before sending. */ int ssh_packet_send1(struct ssh *ssh) { struct session_state *state = ssh->state; u_char buf[8], *cp; int r, padding, len; u_int checksum; /* * If using packet compression, compress the payload of the outgoing * packet. */ if (state->packet_compression) { sshbuf_reset(state->compression_buffer); /* Skip padding. */ if ((r = sshbuf_consume(state->outgoing_packet, 8)) != 0) goto out; /* padding */ if ((r = sshbuf_put(state->compression_buffer, "\0\0\0\0\0\0\0\0", 8)) != 0) goto out; if ((r = compress_buffer(ssh, state->outgoing_packet, state->compression_buffer)) != 0) goto out; sshbuf_reset(state->outgoing_packet); if ((r = sshbuf_putb(state->outgoing_packet, state->compression_buffer)) != 0) goto out; } /* Compute packet length without padding (add checksum, remove padding). */ len = sshbuf_len(state->outgoing_packet) + 4 - 8; /* Insert padding. Initialized to zero in packet_start1() */ padding = 8 - len % 8; if (!cipher_ctx_is_plaintext(state->send_context)) { cp = sshbuf_mutable_ptr(state->outgoing_packet); if (cp == NULL) { r = SSH_ERR_INTERNAL_ERROR; goto out; } arc4random_buf(cp + 8 - padding, padding); } if ((r = sshbuf_consume(state->outgoing_packet, 8 - padding)) != 0) goto out; /* Add check bytes. */ checksum = ssh_crc32(sshbuf_ptr(state->outgoing_packet), sshbuf_len(state->outgoing_packet)); POKE_U32(buf, checksum); if ((r = sshbuf_put(state->outgoing_packet, buf, 4)) != 0) goto out; #ifdef PACKET_DEBUG fprintf(stderr, "packet_send plain: "); sshbuf_dump(state->outgoing_packet, stderr); #endif /* Append to output. */ POKE_U32(buf, len); if ((r = sshbuf_put(state->output, buf, 4)) != 0) goto out; if ((r = sshbuf_reserve(state->output, sshbuf_len(state->outgoing_packet), &cp)) != 0) goto out; if ((r = cipher_crypt(state->send_context, 0, cp, sshbuf_ptr(state->outgoing_packet), sshbuf_len(state->outgoing_packet), 0, 0)) != 0) goto out; #ifdef PACKET_DEBUG fprintf(stderr, "encrypted: "); sshbuf_dump(state->output, stderr); #endif state->p_send.packets++; state->p_send.bytes += len + sshbuf_len(state->outgoing_packet); sshbuf_reset(state->outgoing_packet); /* * Note that the packet is now only buffered in output. It won't be * actually sent until ssh_packet_write_wait or ssh_packet_write_poll * is called. */ r = 0; out: return r; } int ssh_set_newkeys(struct ssh *ssh, int mode) { struct session_state *state = ssh->state; struct sshenc *enc; struct sshmac *mac; struct sshcomp *comp; struct sshcipher_ctx **ccp; struct packet_state *ps; u_int64_t *max_blocks; const char *wmsg, *dir; int r, crypt_type; debug2("set_newkeys: mode %d", mode); if (mode == MODE_OUT) { dir = "output"; ccp = &state->send_context; crypt_type = CIPHER_ENCRYPT; ps = &state->p_send; max_blocks = &state->max_blocks_out; } else { dir = "input"; ccp = &state->receive_context; crypt_type = CIPHER_DECRYPT; ps = &state->p_read; max_blocks = &state->max_blocks_in; } if (state->newkeys[mode] != NULL) { debug("%s: rekeying after %llu %s blocks" " (%llu bytes total)", __func__, (unsigned long long)ps->blocks, dir, (unsigned long long)ps->bytes); cipher_free(*ccp); *ccp = NULL; enc = &state->newkeys[mode]->enc; mac = &state->newkeys[mode]->mac; comp = &state->newkeys[mode]->comp; mac_clear(mac); explicit_bzero(enc->iv, enc->iv_len); explicit_bzero(enc->key, enc->key_len); explicit_bzero(mac->key, mac->key_len); free(enc->name); free(enc->iv); free(enc->key); free(mac->name); free(mac->key); free(comp->name); free(state->newkeys[mode]); } /* note that both bytes and the seqnr are not reset */ ps->packets = ps->blocks = 0; /* move newkeys from kex to state */ if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL) return SSH_ERR_INTERNAL_ERROR; ssh->kex->newkeys[mode] = NULL; enc = &state->newkeys[mode]->enc; mac = &state->newkeys[mode]->mac; comp = &state->newkeys[mode]->comp; if (cipher_authlen(enc->cipher) == 0) { if ((r = mac_init(mac)) != 0) return r; } mac->enabled = 1; DBG(debug("cipher_init_context: %d", mode)); if ((r = cipher_init(ccp, enc->cipher, enc->key, enc->key_len, enc->iv, enc->iv_len, crypt_type)) != 0) return r; if (!state->cipher_warning_done && (wmsg = cipher_warning_message(*ccp)) != NULL) { error("Warning: %s", wmsg); state->cipher_warning_done = 1; } /* Deleting the keys does not gain extra security */ /* explicit_bzero(enc->iv, enc->block_size); explicit_bzero(enc->key, enc->key_len); explicit_bzero(mac->key, mac->key_len); */ if ((comp->type == COMP_ZLIB || (comp->type == COMP_DELAYED && state->after_authentication)) && comp->enabled == 0) { if ((r = ssh_packet_init_compression(ssh)) < 0) return r; if (mode == MODE_OUT) { if ((r = start_compression_out(ssh, 6)) != 0) return r; } else { if ((r = start_compression_in(ssh)) != 0) return r; } comp->enabled = 1; } /* * The 2^(blocksize*2) limit is too expensive for 3DES, * blowfish, etc, so enforce a 1GB limit for small blocksizes. */ if (enc->block_size >= 16) *max_blocks = (u_int64_t)1 << (enc->block_size*2); else *max_blocks = ((u_int64_t)1 << 30) / enc->block_size; if (state->rekey_limit) *max_blocks = MINIMUM(*max_blocks, state->rekey_limit / enc->block_size); debug("rekey after %llu blocks", (unsigned long long)*max_blocks); return 0; } #define MAX_PACKETS (1U<<31) static int ssh_packet_need_rekeying(struct ssh *ssh, u_int outbound_packet_len) { struct session_state *state = ssh->state; u_int32_t out_blocks; /* XXX client can't cope with rekeying pre-auth */ if (!state->after_authentication) return 0; /* Haven't keyed yet or KEX in progress. */ if (ssh->kex == NULL || ssh_packet_is_rekeying(ssh)) return 0; /* Peer can't rekey */ if (ssh->compat & SSH_BUG_NOREKEY) return 0; /* * Permit one packet in or out per rekey - this allows us to * make progress when rekey limits are very small. */ if (state->p_send.packets == 0 && state->p_read.packets == 0) return 0; /* Time-based rekeying */ if (state->rekey_interval != 0 && state->rekey_time + state->rekey_interval <= monotime()) return 1; /* Always rekey when MAX_PACKETS sent in either direction */ if (state->p_send.packets > MAX_PACKETS || state->p_read.packets > MAX_PACKETS) return 1; /* Rekey after (cipher-specific) maxiumum blocks */ out_blocks = ROUNDUP(outbound_packet_len, state->newkeys[MODE_OUT]->enc.block_size); return (state->max_blocks_out && (state->p_send.blocks + out_blocks > state->max_blocks_out)) || (state->max_blocks_in && (state->p_read.blocks > state->max_blocks_in)); } /* * Delayed compression for SSH2 is enabled after authentication: * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent, * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received. */ static int ssh_packet_enable_delayed_compress(struct ssh *ssh) { struct session_state *state = ssh->state; struct sshcomp *comp = NULL; int r, mode; /* * Remember that we are past the authentication step, so rekeying * with COMP_DELAYED will turn on compression immediately. */ state->after_authentication = 1; for (mode = 0; mode < MODE_MAX; mode++) { /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */ if (state->newkeys[mode] == NULL) continue; comp = &state->newkeys[mode]->comp; if (comp && !comp->enabled && comp->type == COMP_DELAYED) { if ((r = ssh_packet_init_compression(ssh)) != 0) return r; if (mode == MODE_OUT) { if ((r = start_compression_out(ssh, 6)) != 0) return r; } else { if ((r = start_compression_in(ssh)) != 0) return r; } comp->enabled = 1; } } return 0; } /* Used to mute debug logging for noisy packet types */ int ssh_packet_log_type(u_char type) { switch (type) { case SSH2_MSG_CHANNEL_DATA: case SSH2_MSG_CHANNEL_EXTENDED_DATA: case SSH2_MSG_CHANNEL_WINDOW_ADJUST: return 0; default: return 1; } } /* * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) */ int ssh_packet_send2_wrapped(struct ssh *ssh) { struct session_state *state = ssh->state; u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH]; u_char tmp, padlen, pad = 0; u_int authlen = 0, aadlen = 0; u_int len; struct sshenc *enc = NULL; struct sshmac *mac = NULL; struct sshcomp *comp = NULL; int r, block_size; if (state->newkeys[MODE_OUT] != NULL) { enc = &state->newkeys[MODE_OUT]->enc; mac = &state->newkeys[MODE_OUT]->mac; comp = &state->newkeys[MODE_OUT]->comp; /* disable mac for authenticated encryption */ if ((authlen = cipher_authlen(enc->cipher)) != 0) mac = NULL; } block_size = enc ? enc->block_size : 8; aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; type = (sshbuf_ptr(state->outgoing_packet))[5]; if (ssh_packet_log_type(type)) debug3("send packet: type %u", type); #ifdef PACKET_DEBUG fprintf(stderr, "plain: "); sshbuf_dump(state->outgoing_packet, stderr); #endif if (comp && comp->enabled) { len = sshbuf_len(state->outgoing_packet); /* skip header, compress only payload */ if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0) goto out; sshbuf_reset(state->compression_buffer); if ((r = compress_buffer(ssh, state->outgoing_packet, state->compression_buffer)) != 0) goto out; sshbuf_reset(state->outgoing_packet); if ((r = sshbuf_put(state->outgoing_packet, "\0\0\0\0\0", 5)) != 0 || (r = sshbuf_putb(state->outgoing_packet, state->compression_buffer)) != 0) goto out; DBG(debug("compression: raw %d compressed %zd", len, sshbuf_len(state->outgoing_packet))); } /* sizeof (packet_len + pad_len + payload) */ len = sshbuf_len(state->outgoing_packet); /* * calc size of padding, alloc space, get random data, * minimum padding is 4 bytes */ len -= aadlen; /* packet length is not encrypted for EtM modes */ padlen = block_size - (len % block_size); if (padlen < 4) padlen += block_size; if (state->extra_pad) { tmp = state->extra_pad; state->extra_pad = ROUNDUP(state->extra_pad, block_size); /* check if roundup overflowed */ if (state->extra_pad < tmp) return SSH_ERR_INVALID_ARGUMENT; tmp = (len + padlen) % state->extra_pad; /* Check whether pad calculation below will underflow */ if (tmp > state->extra_pad) return SSH_ERR_INVALID_ARGUMENT; pad = state->extra_pad - tmp; DBG(debug3("%s: adding %d (len %d padlen %d extra_pad %d)", __func__, pad, len, padlen, state->extra_pad)); tmp = padlen; padlen += pad; /* Check whether padlen calculation overflowed */ if (padlen < tmp) return SSH_ERR_INVALID_ARGUMENT; /* overflow */ state->extra_pad = 0; } if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0) goto out; if (enc && !cipher_ctx_is_plaintext(state->send_context)) { /* random padding */ arc4random_buf(cp, padlen); } else { /* clear padding */ explicit_bzero(cp, padlen); } /* sizeof (packet_len + pad_len + payload + padding) */ len = sshbuf_len(state->outgoing_packet); cp = sshbuf_mutable_ptr(state->outgoing_packet); if (cp == NULL) { r = SSH_ERR_INTERNAL_ERROR; goto out; } /* packet_length includes payload, padding and padding length field */ POKE_U32(cp, len - 4); cp[4] = padlen; DBG(debug("send: len %d (includes padlen %d, aadlen %d)", len, padlen, aadlen)); /* compute MAC over seqnr and packet(length fields, payload, padding) */ if (mac && mac->enabled && !mac->etm) { if ((r = mac_compute(mac, state->p_send.seqnr, sshbuf_ptr(state->outgoing_packet), len, macbuf, sizeof(macbuf))) != 0) goto out; DBG(debug("done calc MAC out #%d", state->p_send.seqnr)); } /* encrypt packet and append to output buffer. */ if ((r = sshbuf_reserve(state->output, sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0) goto out; if ((r = cipher_crypt(state->send_context, state->p_send.seqnr, cp, sshbuf_ptr(state->outgoing_packet), len - aadlen, aadlen, authlen)) != 0) goto out; /* append unencrypted MAC */ if (mac && mac->enabled) { if (mac->etm) { /* EtM: compute mac over aadlen + cipher text */ if ((r = mac_compute(mac, state->p_send.seqnr, cp, len, macbuf, sizeof(macbuf))) != 0) goto out; DBG(debug("done calc MAC(EtM) out #%d", state->p_send.seqnr)); } if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0) goto out; } #ifdef PACKET_DEBUG fprintf(stderr, "encrypted: "); sshbuf_dump(state->output, stderr); #endif /* increment sequence number for outgoing packets */ if (++state->p_send.seqnr == 0) logit("outgoing seqnr wraps around"); if (++state->p_send.packets == 0) if (!(ssh->compat & SSH_BUG_NOREKEY)) return SSH_ERR_NEED_REKEY; state->p_send.blocks += len / block_size; state->p_send.bytes += len; sshbuf_reset(state->outgoing_packet); if (type == SSH2_MSG_NEWKEYS) r = ssh_set_newkeys(ssh, MODE_OUT); else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side) r = ssh_packet_enable_delayed_compress(ssh); else r = 0; out: return r; } /* returns non-zero if the specified packet type is usec by KEX */ static int ssh_packet_type_is_kex(u_char type) { return type >= SSH2_MSG_TRANSPORT_MIN && type <= SSH2_MSG_TRANSPORT_MAX && type != SSH2_MSG_SERVICE_REQUEST && type != SSH2_MSG_SERVICE_ACCEPT && type != SSH2_MSG_EXT_INFO; } int ssh_packet_send2(struct ssh *ssh) { struct session_state *state = ssh->state; struct packet *p; u_char type; int r, need_rekey; if (sshbuf_len(state->outgoing_packet) < 6) return SSH_ERR_INTERNAL_ERROR; type = sshbuf_ptr(state->outgoing_packet)[5]; need_rekey = !ssh_packet_type_is_kex(type) && ssh_packet_need_rekeying(ssh, sshbuf_len(state->outgoing_packet)); /* * During rekeying we can only send key exchange messages. * Queue everything else. */ if ((need_rekey || state->rekeying) && !ssh_packet_type_is_kex(type)) { if (need_rekey) debug3("%s: rekex triggered", __func__); debug("enqueue packet: %u", type); p = calloc(1, sizeof(*p)); if (p == NULL) return SSH_ERR_ALLOC_FAIL; p->type = type; p->payload = state->outgoing_packet; TAILQ_INSERT_TAIL(&state->outgoing, p, next); state->outgoing_packet = sshbuf_new(); if (state->outgoing_packet == NULL) return SSH_ERR_ALLOC_FAIL; if (need_rekey) { /* * This packet triggered a rekey, so send the * KEXINIT now. * NB. reenters this function via kex_start_rekex(). */ return kex_start_rekex(ssh); } return 0; } /* rekeying starts with sending KEXINIT */ if (type == SSH2_MSG_KEXINIT) state->rekeying = 1; if ((r = ssh_packet_send2_wrapped(ssh)) != 0) return r; /* after a NEWKEYS message we can send the complete queue */ if (type == SSH2_MSG_NEWKEYS) { state->rekeying = 0; state->rekey_time = monotime(); while ((p = TAILQ_FIRST(&state->outgoing))) { type = p->type; /* * If this packet triggers a rekex, then skip the * remaining packets in the queue for now. * NB. re-enters this function via kex_start_rekex. */ if (ssh_packet_need_rekeying(ssh, sshbuf_len(p->payload))) { debug3("%s: queued packet triggered rekex", __func__); return kex_start_rekex(ssh); } debug("dequeue packet: %u", type); sshbuf_free(state->outgoing_packet); state->outgoing_packet = p->payload; TAILQ_REMOVE(&state->outgoing, p, next); memset(p, 0, sizeof(*p)); free(p); if ((r = ssh_packet_send2_wrapped(ssh)) != 0) return r; } } return 0; } /* * Waits until a packet has been received, and returns its type. Note that * no other data is processed until this returns, so this function should not * be used during the interactive session. */ int ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) { struct session_state *state = ssh->state; int len, r, ms_remain; fd_set *setp; char buf[8192]; struct timeval timeout, start, *timeoutp = NULL; DBG(debug("packet_read()")); setp = calloc(howmany(state->connection_in + 1, NFDBITS), sizeof(fd_mask)); if (setp == NULL) return SSH_ERR_ALLOC_FAIL; /* * Since we are blocking, ensure that all written packets have * been sent. */ if ((r = ssh_packet_write_wait(ssh)) != 0) goto out; /* Stay in the loop until we have received a complete packet. */ for (;;) { /* Try to read a packet from the buffer. */ r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p); if (r != 0) break; if (!compat20 && ( *typep == SSH_SMSG_SUCCESS || *typep == SSH_SMSG_FAILURE || *typep == SSH_CMSG_EOF || *typep == SSH_CMSG_EXIT_CONFIRMATION)) if ((r = sshpkt_get_end(ssh)) != 0) break; /* If we got a packet, return it. */ if (*typep != SSH_MSG_NONE) break; /* * Otherwise, wait for some data to arrive, add it to the * buffer, and try again. */ memset(setp, 0, howmany(state->connection_in + 1, NFDBITS) * sizeof(fd_mask)); FD_SET(state->connection_in, setp); if (state->packet_timeout_ms > 0) { ms_remain = state->packet_timeout_ms; timeoutp = &timeout; } /* Wait for some data to arrive. */ for (;;) { if (state->packet_timeout_ms != -1) { ms_to_timeval(&timeout, ms_remain); gettimeofday(&start, NULL); } if ((r = select(state->connection_in + 1, setp, NULL, NULL, timeoutp)) >= 0) break; if (errno != EAGAIN && errno != EINTR && errno != EWOULDBLOCK) break; if (state->packet_timeout_ms == -1) continue; ms_subtract_diff(&start, &ms_remain); if (ms_remain <= 0) { r = 0; break; } } if (r == 0) return SSH_ERR_CONN_TIMEOUT; /* Read data from the socket. */ len = read(state->connection_in, buf, sizeof(buf)); if (len == 0) { r = SSH_ERR_CONN_CLOSED; goto out; } if (len < 0) { r = SSH_ERR_SYSTEM_ERROR; goto out; } /* Append it to the buffer. */ if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0) goto out; } out: free(setp); return r; } int ssh_packet_read(struct ssh *ssh) { u_char type; int r; if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) fatal("%s: %s", __func__, ssh_err(r)); return type; } /* * Waits until a packet has been received, verifies that its type matches * that given, and gives a fatal error and exits if there is a mismatch. */ int ssh_packet_read_expect(struct ssh *ssh, u_int expected_type) { int r; u_char type; if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) return r; if (type != expected_type) { if ((r = sshpkt_disconnect(ssh, "Protocol error: expected packet type %d, got %d", expected_type, type)) != 0) return r; return SSH_ERR_PROTOCOL_ERROR; } return 0; } /* Checks if a full packet is available in the data received so far via * packet_process_incoming. If so, reads the packet; otherwise returns * SSH_MSG_NONE. This does not wait for data from the connection. * * SSH_MSG_DISCONNECT is handled specially here. Also, * SSH_MSG_IGNORE messages are skipped by this function and are never returned * to higher levels. */ int ssh_packet_read_poll1(struct ssh *ssh, u_char *typep) { struct session_state *state = ssh->state; u_int len, padded_len; const char *emsg; const u_char *cp; u_char *p; u_int checksum, stored_checksum; int r; *typep = SSH_MSG_NONE; /* Check if input size is less than minimum packet size. */ if (sshbuf_len(state->input) < 4 + 8) return 0; /* Get length of incoming packet. */ len = PEEK_U32(sshbuf_ptr(state->input)); if (len < 1 + 2 + 2 || len > 256 * 1024) { if ((r = sshpkt_disconnect(ssh, "Bad packet length %u", len)) != 0) return r; return SSH_ERR_CONN_CORRUPT; } padded_len = (len + 8) & ~7; /* Check if the packet has been entirely received. */ if (sshbuf_len(state->input) < 4 + padded_len) return 0; /* The entire packet is in buffer. */ /* Consume packet length. */ if ((r = sshbuf_consume(state->input, 4)) != 0) goto out; /* * Cryptographic attack detector for ssh * (C)1998 CORE-SDI, Buenos Aires Argentina * Ariel Futoransky(futo@core-sdi.com) */ if (!cipher_ctx_is_plaintext(state->receive_context)) { emsg = NULL; switch (detect_attack(&state->deattack, sshbuf_ptr(state->input), padded_len)) { case DEATTACK_OK: break; case DEATTACK_DETECTED: emsg = "crc32 compensation attack detected"; break; case DEATTACK_DOS_DETECTED: emsg = "deattack denial of service detected"; break; default: emsg = "deattack error"; break; } if (emsg != NULL) { error("%s", emsg); if ((r = sshpkt_disconnect(ssh, "%s", emsg)) != 0 || (r = ssh_packet_write_wait(ssh)) != 0) return r; return SSH_ERR_CONN_CORRUPT; } } /* Decrypt data to incoming_packet. */ sshbuf_reset(state->incoming_packet); if ((r = sshbuf_reserve(state->incoming_packet, padded_len, &p)) != 0) goto out; if ((r = cipher_crypt(state->receive_context, 0, p, sshbuf_ptr(state->input), padded_len, 0, 0)) != 0) goto out; if ((r = sshbuf_consume(state->input, padded_len)) != 0) goto out; #ifdef PACKET_DEBUG fprintf(stderr, "read_poll plain: "); sshbuf_dump(state->incoming_packet, stderr); #endif /* Compute packet checksum. */ checksum = ssh_crc32(sshbuf_ptr(state->incoming_packet), sshbuf_len(state->incoming_packet) - 4); /* Skip padding. */ if ((r = sshbuf_consume(state->incoming_packet, 8 - len % 8)) != 0) goto out; /* Test check bytes. */ if (len != sshbuf_len(state->incoming_packet)) { error("%s: len %d != sshbuf_len %zd", __func__, len, sshbuf_len(state->incoming_packet)); if ((r = sshpkt_disconnect(ssh, "invalid packet length")) != 0 || (r = ssh_packet_write_wait(ssh)) != 0) return r; return SSH_ERR_CONN_CORRUPT; } cp = sshbuf_ptr(state->incoming_packet) + len - 4; stored_checksum = PEEK_U32(cp); if (checksum != stored_checksum) { error("Corrupted check bytes on input"); if ((r = sshpkt_disconnect(ssh, "connection corrupted")) != 0 || (r = ssh_packet_write_wait(ssh)) != 0) return r; return SSH_ERR_CONN_CORRUPT; } if ((r = sshbuf_consume_end(state->incoming_packet, 4)) < 0) goto out; if (state->packet_compression) { sshbuf_reset(state->compression_buffer); if ((r = uncompress_buffer(ssh, state->incoming_packet, state->compression_buffer)) != 0) goto out; sshbuf_reset(state->incoming_packet); if ((r = sshbuf_putb(state->incoming_packet, state->compression_buffer)) != 0) goto out; } state->p_read.packets++; state->p_read.bytes += padded_len + 4; if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) goto out; if (*typep < SSH_MSG_MIN || *typep > SSH_MSG_MAX) { error("Invalid ssh1 packet type: %d", *typep); if ((r = sshpkt_disconnect(ssh, "invalid packet type")) != 0 || (r = ssh_packet_write_wait(ssh)) != 0) return r; return SSH_ERR_PROTOCOL_ERROR; } r = 0; out: return r; } static int ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) { struct session_state *state = ssh->state; const u_char *cp; size_t need; int r; if (ssh->kex) return SSH_ERR_INTERNAL_ERROR; *typep = SSH_MSG_NONE; cp = sshbuf_ptr(state->input); if (state->packlen == 0) { if (sshbuf_len(state->input) < 4 + 1) return 0; /* packet is incomplete */ state->packlen = PEEK_U32(cp); if (state->packlen < 4 + 1 || state->packlen > PACKET_MAX_SIZE) return SSH_ERR_MESSAGE_INCOMPLETE; } need = state->packlen + 4; if (sshbuf_len(state->input) < need) return 0; /* packet is incomplete */ sshbuf_reset(state->incoming_packet); if ((r = sshbuf_put(state->incoming_packet, cp + 4, state->packlen)) != 0 || (r = sshbuf_consume(state->input, need)) != 0 || (r = sshbuf_get_u8(state->incoming_packet, NULL)) != 0 || (r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) return r; if (ssh_packet_log_type(*typep)) debug3("%s: type %u", __func__, *typep); /* sshbuf_dump(state->incoming_packet, stderr); */ /* reset for next packet */ state->packlen = 0; return r; } int ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) { struct session_state *state = ssh->state; u_int padlen, need; u_char *cp; u_int maclen, aadlen = 0, authlen = 0, block_size; struct sshenc *enc = NULL; struct sshmac *mac = NULL; struct sshcomp *comp = NULL; int r; if (state->mux) return ssh_packet_read_poll2_mux(ssh, typep, seqnr_p); *typep = SSH_MSG_NONE; if (state->packet_discard) return 0; if (state->newkeys[MODE_IN] != NULL) { enc = &state->newkeys[MODE_IN]->enc; mac = &state->newkeys[MODE_IN]->mac; comp = &state->newkeys[MODE_IN]->comp; /* disable mac for authenticated encryption */ if ((authlen = cipher_authlen(enc->cipher)) != 0) mac = NULL; } maclen = mac && mac->enabled ? mac->mac_len : 0; block_size = enc ? enc->block_size : 8; aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; if (aadlen && state->packlen == 0) { if (cipher_get_length(state->receive_context, &state->packlen, state->p_read.seqnr, sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0) return 0; if (state->packlen < 1 + 4 || state->packlen > PACKET_MAX_SIZE) { #ifdef PACKET_DEBUG sshbuf_dump(state->input, stderr); #endif logit("Bad packet length %u.", state->packlen); if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) return r; return SSH_ERR_CONN_CORRUPT; } sshbuf_reset(state->incoming_packet); } else if (state->packlen == 0) { /* * check if input size is less than the cipher block size, * decrypt first block and extract length of incoming packet */ if (sshbuf_len(state->input) < block_size) return 0; sshbuf_reset(state->incoming_packet); if ((r = sshbuf_reserve(state->incoming_packet, block_size, &cp)) != 0) goto out; if ((r = cipher_crypt(state->receive_context, state->p_send.seqnr, cp, sshbuf_ptr(state->input), block_size, 0, 0)) != 0) goto out; state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet)); if (state->packlen < 1 + 4 || state->packlen > PACKET_MAX_SIZE) { #ifdef PACKET_DEBUG fprintf(stderr, "input: \n"); sshbuf_dump(state->input, stderr); fprintf(stderr, "incoming_packet: \n"); sshbuf_dump(state->incoming_packet, stderr); #endif logit("Bad packet length %u.", state->packlen); return ssh_packet_start_discard(ssh, enc, mac, 0, PACKET_MAX_SIZE); } if ((r = sshbuf_consume(state->input, block_size)) != 0) goto out; } DBG(debug("input: packet len %u", state->packlen+4)); if (aadlen) { /* only the payload is encrypted */ need = state->packlen; } else { /* * the payload size and the payload are encrypted, but we * have a partial packet of block_size bytes */ need = 4 + state->packlen - block_size; } DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d," " aadlen %d", block_size, need, maclen, authlen, aadlen)); if (need % block_size != 0) { logit("padding error: need %d block %d mod %d", need, block_size, need % block_size); return ssh_packet_start_discard(ssh, enc, mac, 0, PACKET_MAX_SIZE - block_size); } /* * check if the entire packet has been received and * decrypt into incoming_packet: * 'aadlen' bytes are unencrypted, but authenticated. * 'need' bytes are encrypted, followed by either * 'authlen' bytes of authentication tag or * 'maclen' bytes of message authentication code. */ if (sshbuf_len(state->input) < aadlen + need + authlen + maclen) return 0; /* packet is incomplete */ #ifdef PACKET_DEBUG fprintf(stderr, "read_poll enc/full: "); sshbuf_dump(state->input, stderr); #endif /* EtM: check mac over encrypted input */ if (mac && mac->enabled && mac->etm) { if ((r = mac_check(mac, state->p_read.seqnr, sshbuf_ptr(state->input), aadlen + need, sshbuf_ptr(state->input) + aadlen + need + authlen, maclen)) != 0) { if (r == SSH_ERR_MAC_INVALID) logit("Corrupted MAC on input."); goto out; } } if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need, &cp)) != 0) goto out; if ((r = cipher_crypt(state->receive_context, state->p_read.seqnr, cp, sshbuf_ptr(state->input), need, aadlen, authlen)) != 0) goto out; if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0) goto out; if (mac && mac->enabled) { /* Not EtM: check MAC over cleartext */ if (!mac->etm && (r = mac_check(mac, state->p_read.seqnr, sshbuf_ptr(state->incoming_packet), sshbuf_len(state->incoming_packet), sshbuf_ptr(state->input), maclen)) != 0) { if (r != SSH_ERR_MAC_INVALID) goto out; logit("Corrupted MAC on input."); if (need > PACKET_MAX_SIZE) return SSH_ERR_INTERNAL_ERROR; return ssh_packet_start_discard(ssh, enc, mac, sshbuf_len(state->incoming_packet), PACKET_MAX_SIZE - need); } /* Remove MAC from input buffer */ DBG(debug("MAC #%d ok", state->p_read.seqnr)); if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0) goto out; } if (seqnr_p != NULL) *seqnr_p = state->p_read.seqnr; if (++state->p_read.seqnr == 0) logit("incoming seqnr wraps around"); if (++state->p_read.packets == 0) if (!(ssh->compat & SSH_BUG_NOREKEY)) return SSH_ERR_NEED_REKEY; state->p_read.blocks += (state->packlen + 4) / block_size; state->p_read.bytes += state->packlen + 4; /* get padlen */ padlen = sshbuf_ptr(state->incoming_packet)[4]; DBG(debug("input: padlen %d", padlen)); if (padlen < 4) { if ((r = sshpkt_disconnect(ssh, "Corrupted padlen %d on input.", padlen)) != 0 || (r = ssh_packet_write_wait(ssh)) != 0) return r; return SSH_ERR_CONN_CORRUPT; } /* skip packet size + padlen, discard padding */ if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 || ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0)) goto out; DBG(debug("input: len before de-compress %zd", sshbuf_len(state->incoming_packet))); if (comp && comp->enabled) { sshbuf_reset(state->compression_buffer); if ((r = uncompress_buffer(ssh, state->incoming_packet, state->compression_buffer)) != 0) goto out; sshbuf_reset(state->incoming_packet); if ((r = sshbuf_putb(state->incoming_packet, state->compression_buffer)) != 0) goto out; DBG(debug("input: len after de-compress %zd", sshbuf_len(state->incoming_packet))); } /* * get packet type, implies consume. * return length of payload (without type field) */ if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) goto out; if (ssh_packet_log_type(*typep)) debug3("receive packet: type %u", *typep); if (*typep < SSH2_MSG_MIN || *typep >= SSH2_MSG_LOCAL_MIN) { if ((r = sshpkt_disconnect(ssh, "Invalid ssh2 packet type: %d", *typep)) != 0 || (r = ssh_packet_write_wait(ssh)) != 0) return r; return SSH_ERR_PROTOCOL_ERROR; } if (state->hook_in != NULL && (r = state->hook_in(ssh, state->incoming_packet, typep, state->hook_in_ctx)) != 0) return r; if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side) r = ssh_packet_enable_delayed_compress(ssh); else r = 0; #ifdef PACKET_DEBUG fprintf(stderr, "read/plain[%d]:\r\n", *typep); sshbuf_dump(state->incoming_packet, stderr); #endif /* reset for next packet */ state->packlen = 0; /* do we need to rekey? */ if (ssh_packet_need_rekeying(ssh, 0)) { debug3("%s: rekex triggered", __func__); if ((r = kex_start_rekex(ssh)) != 0) return r; } out: return r; } int ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) { struct session_state *state = ssh->state; u_int reason, seqnr; int r; u_char *msg; for (;;) { msg = NULL; if (compat20) { r = ssh_packet_read_poll2(ssh, typep, seqnr_p); if (r != 0) return r; if (*typep) { state->keep_alive_timeouts = 0; DBG(debug("received packet type %d", *typep)); } switch (*typep) { case SSH2_MSG_IGNORE: debug3("Received SSH2_MSG_IGNORE"); break; case SSH2_MSG_DEBUG: if ((r = sshpkt_get_u8(ssh, NULL)) != 0 || (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 || (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) { free(msg); return r; } debug("Remote: %.900s", msg); free(msg); break; case SSH2_MSG_DISCONNECT: if ((r = sshpkt_get_u32(ssh, &reason)) != 0 || (r = sshpkt_get_string(ssh, &msg, NULL)) != 0) return r; /* Ignore normal client exit notifications */ do_log2(ssh->state->server_side && reason == SSH2_DISCONNECT_BY_APPLICATION ? SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR, "Received disconnect from %s port %d:" "%u: %.400s", ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), reason, msg); free(msg); return SSH_ERR_DISCONNECTED; case SSH2_MSG_UNIMPLEMENTED: if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0) return r; debug("Received SSH2_MSG_UNIMPLEMENTED for %u", seqnr); break; default: return 0; } } else { r = ssh_packet_read_poll1(ssh, typep); switch (*typep) { case SSH_MSG_NONE: return SSH_MSG_NONE; case SSH_MSG_IGNORE: break; case SSH_MSG_DEBUG: if ((r = sshpkt_get_string(ssh, &msg, NULL)) != 0) return r; debug("Remote: %.900s", msg); free(msg); break; case SSH_MSG_DISCONNECT: if ((r = sshpkt_get_string(ssh, &msg, NULL)) != 0) return r; logit("Received disconnect from %s port %d: " "%.400s", ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), msg); free(msg); return SSH_ERR_DISCONNECTED; default: DBG(debug("received packet type %d", *typep)); return 0; } } } } /* * Buffers the given amount of input characters. This is intended to be used * together with packet_read_poll. */ int ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len) { struct session_state *state = ssh->state; int r; if (state->packet_discard) { state->keep_alive_timeouts = 0; /* ?? */ if (len >= state->packet_discard) { if ((r = ssh_packet_stop_discard(ssh)) != 0) return r; } state->packet_discard -= len; return 0; } if ((r = sshbuf_put(ssh->state->input, buf, len)) != 0) return r; return 0; } int ssh_packet_remaining(struct ssh *ssh) { return sshbuf_len(ssh->state->incoming_packet); } /* * Sends a diagnostic message from the server to the client. This message * can be sent at any time (but not while constructing another message). The * message is printed immediately, but only if the client is being executed * in verbose mode. These messages are primarily intended to ease debugging * authentication problems. The length of the formatted message must not * exceed 1024 bytes. This will automatically call ssh_packet_write_wait. */ void ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...) { char buf[1024]; va_list args; int r; if (compat20 && (ssh->compat & SSH_BUG_DEBUG)) return; va_start(args, fmt); vsnprintf(buf, sizeof(buf), fmt, args); va_end(args); if (compat20) { if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 || (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */ (r = sshpkt_put_cstring(ssh, buf)) != 0 || (r = sshpkt_put_cstring(ssh, "")) != 0 || (r = sshpkt_send(ssh)) != 0) fatal("%s: %s", __func__, ssh_err(r)); } else { if ((r = sshpkt_start(ssh, SSH_MSG_DEBUG)) != 0 || (r = sshpkt_put_cstring(ssh, buf)) != 0 || (r = sshpkt_send(ssh)) != 0) fatal("%s: %s", __func__, ssh_err(r)); } if ((r = ssh_packet_write_wait(ssh)) != 0) fatal("%s: %s", __func__, ssh_err(r)); } /* * Pretty-print connection-terminating errors and exit. */ void sshpkt_fatal(struct ssh *ssh, const char *tag, int r) { switch (r) { case SSH_ERR_CONN_CLOSED: logdie("Connection closed by %.200s port %d", ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); case SSH_ERR_CONN_TIMEOUT: logdie("Connection %s %.200s port %d timed out", ssh->state->server_side ? "from" : "to", ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); case SSH_ERR_DISCONNECTED: logdie("Disconnected from %.200s port %d", ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); case SSH_ERR_SYSTEM_ERROR: if (errno == ECONNRESET) logdie("Connection reset by %.200s port %d", ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); /* FALLTHROUGH */ case SSH_ERR_NO_CIPHER_ALG_MATCH: case SSH_ERR_NO_MAC_ALG_MATCH: case SSH_ERR_NO_COMPRESS_ALG_MATCH: case SSH_ERR_NO_KEX_ALG_MATCH: case SSH_ERR_NO_HOSTKEY_ALG_MATCH: if (ssh && ssh->kex && ssh->kex->failed_choice) { - BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL); + BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL, "ssh"); logdie("Unable to negotiate with %.200s port %d: %s. " "Their offer: %s", ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), ssh_err(r), ssh->kex->failed_choice); } /* FALLTHROUGH */ default: logdie("%s%sConnection %s %.200s port %d: %s", tag != NULL ? tag : "", tag != NULL ? ": " : "", ssh->state->server_side ? "from" : "to", ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), ssh_err(r)); } } /* * Logs the error plus constructs and sends a disconnect packet, closes the * connection, and exits. This function never returns. The error message * should not contain a newline. The length of the formatted message must * not exceed 1024 bytes. */ void ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...) { char buf[1024]; va_list args; static int disconnecting = 0; int r; if (disconnecting) /* Guard against recursive invocations. */ fatal("packet_disconnect called recursively."); disconnecting = 1; /* * Format the message. Note that the caller must make sure the * message is of limited size. */ va_start(args, fmt); vsnprintf(buf, sizeof(buf), fmt, args); va_end(args); /* Display the error locally */ logit("Disconnecting: %.100s", buf); /* * Send the disconnect message to the other side, and wait * for it to get sent. */ if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0) sshpkt_fatal(ssh, __func__, r); if ((r = ssh_packet_write_wait(ssh)) != 0) sshpkt_fatal(ssh, __func__, r); /* Close the connection. */ ssh_packet_close(ssh); cleanup_exit(255); } /* * Checks if there is any buffered output, and tries to write some of * the output. */ int ssh_packet_write_poll(struct ssh *ssh) { struct session_state *state = ssh->state; int len = sshbuf_len(state->output); int r; if (len > 0) { len = write(state->connection_out, sshbuf_ptr(state->output), len); if (len == -1) { if (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK) return 0; return SSH_ERR_SYSTEM_ERROR; } if (len == 0) return SSH_ERR_CONN_CLOSED; if ((r = sshbuf_consume(state->output, len)) != 0) return r; } return 0; } /* * Calls packet_write_poll repeatedly until all pending output data has been * written. */ int ssh_packet_write_wait(struct ssh *ssh) { fd_set *setp; int ret, r, ms_remain = 0; struct timeval start, timeout, *timeoutp = NULL; struct session_state *state = ssh->state; setp = calloc(howmany(state->connection_out + 1, NFDBITS), sizeof(fd_mask)); if (setp == NULL) return SSH_ERR_ALLOC_FAIL; if ((r = ssh_packet_write_poll(ssh)) != 0) { free(setp); return r; } while (ssh_packet_have_data_to_write(ssh)) { memset(setp, 0, howmany(state->connection_out + 1, NFDBITS) * sizeof(fd_mask)); FD_SET(state->connection_out, setp); if (state->packet_timeout_ms > 0) { ms_remain = state->packet_timeout_ms; timeoutp = &timeout; } for (;;) { if (state->packet_timeout_ms != -1) { ms_to_timeval(&timeout, ms_remain); gettimeofday(&start, NULL); } if ((ret = select(state->connection_out + 1, NULL, setp, NULL, timeoutp)) >= 0) break; if (errno != EAGAIN && errno != EINTR && errno != EWOULDBLOCK) break; if (state->packet_timeout_ms == -1) continue; ms_subtract_diff(&start, &ms_remain); if (ms_remain <= 0) { ret = 0; break; } } if (ret == 0) { free(setp); return SSH_ERR_CONN_TIMEOUT; } if ((r = ssh_packet_write_poll(ssh)) != 0) { free(setp); return r; } } free(setp); return 0; } /* Returns true if there is buffered data to write to the connection. */ int ssh_packet_have_data_to_write(struct ssh *ssh) { return sshbuf_len(ssh->state->output) != 0; } /* Returns true if there is not too much data to write to the connection. */ int ssh_packet_not_very_much_data_to_write(struct ssh *ssh) { if (ssh->state->interactive_mode) return sshbuf_len(ssh->state->output) < 16384; else return sshbuf_len(ssh->state->output) < 128 * 1024; } void ssh_packet_set_tos(struct ssh *ssh, int tos) { #ifndef IP_TOS_IS_BROKEN if (!ssh_packet_connection_is_on_socket(ssh)) return; switch (ssh_packet_connection_af(ssh)) { # ifdef IP_TOS case AF_INET: debug3("%s: set IP_TOS 0x%02x", __func__, tos); if (setsockopt(ssh->state->connection_in, IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0) error("setsockopt IP_TOS %d: %.100s:", tos, strerror(errno)); break; # endif /* IP_TOS */ # ifdef IPV6_TCLASS case AF_INET6: debug3("%s: set IPV6_TCLASS 0x%02x", __func__, tos); if (setsockopt(ssh->state->connection_in, IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos)) < 0) error("setsockopt IPV6_TCLASS %d: %.100s:", tos, strerror(errno)); break; # endif /* IPV6_TCLASS */ } #endif /* IP_TOS_IS_BROKEN */ } /* Informs that the current session is interactive. Sets IP flags for that. */ void ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk) { struct session_state *state = ssh->state; if (state->set_interactive_called) return; state->set_interactive_called = 1; /* Record that we are in interactive mode. */ state->interactive_mode = interactive; /* Only set socket options if using a socket. */ if (!ssh_packet_connection_is_on_socket(ssh)) return; set_nodelay(state->connection_in); ssh_packet_set_tos(ssh, interactive ? qos_interactive : qos_bulk); } /* Returns true if the current connection is interactive. */ int ssh_packet_is_interactive(struct ssh *ssh) { return ssh->state->interactive_mode; } int ssh_packet_set_maxsize(struct ssh *ssh, u_int s) { struct session_state *state = ssh->state; if (state->set_maxsize_called) { logit("packet_set_maxsize: called twice: old %d new %d", state->max_packet_size, s); return -1; } if (s < 4 * 1024 || s > 1024 * 1024) { logit("packet_set_maxsize: bad size %d", s); return -1; } state->set_maxsize_called = 1; debug("packet_set_maxsize: setting to %d", s); state->max_packet_size = s; return s; } int ssh_packet_inc_alive_timeouts(struct ssh *ssh) { return ++ssh->state->keep_alive_timeouts; } void ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka) { ssh->state->keep_alive_timeouts = ka; } u_int ssh_packet_get_maxsize(struct ssh *ssh) { return ssh->state->max_packet_size; } /* * 9.2. Ignored Data Message * * byte SSH_MSG_IGNORE * string data * * All implementations MUST understand (and ignore) this message at any * time (after receiving the protocol version). No implementation is * required to send them. This message can be used as an additional * protection measure against advanced traffic analysis techniques. */ void ssh_packet_send_ignore(struct ssh *ssh, int nbytes) { u_int32_t rnd = 0; int r, i; if ((r = sshpkt_start(ssh, compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE)) != 0 || (r = sshpkt_put_u32(ssh, nbytes)) != 0) fatal("%s: %s", __func__, ssh_err(r)); for (i = 0; i < nbytes; i++) { if (i % 4 == 0) rnd = arc4random(); if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0) fatal("%s: %s", __func__, ssh_err(r)); rnd >>= 8; } } void ssh_packet_set_rekey_limits(struct ssh *ssh, u_int64_t bytes, time_t seconds) { debug3("rekey after %llu bytes, %d seconds", (unsigned long long)bytes, (int)seconds); ssh->state->rekey_limit = bytes; ssh->state->rekey_interval = seconds; } time_t ssh_packet_get_rekey_timeout(struct ssh *ssh) { time_t seconds; seconds = ssh->state->rekey_time + ssh->state->rekey_interval - monotime(); return (seconds <= 0 ? 1 : seconds); } void ssh_packet_set_server(struct ssh *ssh) { ssh->state->server_side = 1; } void ssh_packet_set_authenticated(struct ssh *ssh) { ssh->state->after_authentication = 1; } void * ssh_packet_get_input(struct ssh *ssh) { return (void *)ssh->state->input; } void * ssh_packet_get_output(struct ssh *ssh) { return (void *)ssh->state->output; } /* Reset after_authentication and reset compression in post-auth privsep */ static int ssh_packet_set_postauth(struct ssh *ssh) { int r; debug("%s: called", __func__); /* This was set in net child, but is not visible in user child */ ssh->state->after_authentication = 1; ssh->state->rekeying = 0; if ((r = ssh_packet_enable_delayed_compress(ssh)) != 0) return r; return 0; } /* Packet state (de-)serialization for privsep */ /* turn kex into a blob for packet state serialization */ static int kex_to_blob(struct sshbuf *m, struct kex *kex) { int r; if ((r = sshbuf_put_string(m, kex->session_id, kex->session_id_len)) != 0 || (r = sshbuf_put_u32(m, kex->we_need)) != 0 || (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 || (r = sshbuf_put_u32(m, kex->kex_type)) != 0 || (r = sshbuf_put_stringb(m, kex->my)) != 0 || (r = sshbuf_put_stringb(m, kex->peer)) != 0 || (r = sshbuf_put_u32(m, kex->flags)) != 0 || (r = sshbuf_put_cstring(m, kex->client_version_string)) != 0 || (r = sshbuf_put_cstring(m, kex->server_version_string)) != 0) return r; return 0; } /* turn key exchange results into a blob for packet state serialization */ static int newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode) { struct sshbuf *b; struct sshcipher_ctx *cc; struct sshcomp *comp; struct sshenc *enc; struct sshmac *mac; struct newkeys *newkey; int r; if ((newkey = ssh->state->newkeys[mode]) == NULL) return SSH_ERR_INTERNAL_ERROR; enc = &newkey->enc; mac = &newkey->mac; comp = &newkey->comp; cc = (mode == MODE_OUT) ? ssh->state->send_context : ssh->state->receive_context; if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0) return r; if ((b = sshbuf_new()) == NULL) return SSH_ERR_ALLOC_FAIL; /* The cipher struct is constant and shared, you export pointer */ if ((r = sshbuf_put_cstring(b, enc->name)) != 0 || (r = sshbuf_put(b, &enc->cipher, sizeof(enc->cipher))) != 0 || (r = sshbuf_put_u32(b, enc->enabled)) != 0 || (r = sshbuf_put_u32(b, enc->block_size)) != 0 || (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 || (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0) goto out; if (cipher_authlen(enc->cipher) == 0) { if ((r = sshbuf_put_cstring(b, mac->name)) != 0 || (r = sshbuf_put_u32(b, mac->enabled)) != 0 || (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0) goto out; } if ((r = sshbuf_put_u32(b, comp->type)) != 0 || (r = sshbuf_put_cstring(b, comp->name)) != 0) goto out; r = sshbuf_put_stringb(m, b); out: sshbuf_free(b); return r; } /* serialize packet state into a blob */ int ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m) { struct session_state *state = ssh->state; u_char *p; size_t slen, rlen; int r, ssh1cipher; if (!compat20) { ssh1cipher = cipher_ctx_get_number(state->receive_context); slen = cipher_get_keyiv_len(state->send_context); rlen = cipher_get_keyiv_len(state->receive_context); if ((r = sshbuf_put_u32(m, state->remote_protocol_flags)) != 0 || (r = sshbuf_put_u32(m, ssh1cipher)) != 0 || (r = sshbuf_put_string(m, state->ssh1_key, state->ssh1_keylen)) != 0 || (r = sshbuf_put_u32(m, slen)) != 0 || (r = sshbuf_reserve(m, slen, &p)) != 0 || (r = cipher_get_keyiv(state->send_context, p, slen)) != 0 || (r = sshbuf_put_u32(m, rlen)) != 0 || (r = sshbuf_reserve(m, rlen, &p)) != 0 || (r = cipher_get_keyiv(state->receive_context, p, rlen)) != 0) return r; } else { if ((r = kex_to_blob(m, ssh->kex)) != 0 || (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 || (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 || (r = sshbuf_put_u64(m, state->rekey_limit)) != 0 || (r = sshbuf_put_u32(m, state->rekey_interval)) != 0 || (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 || (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 || (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 || (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 || (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 || (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 || (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 || (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0) return r; } slen = cipher_get_keycontext(state->send_context, NULL); rlen = cipher_get_keycontext(state->receive_context, NULL); if ((r = sshbuf_put_u32(m, slen)) != 0 || (r = sshbuf_reserve(m, slen, &p)) != 0) return r; if (cipher_get_keycontext(state->send_context, p) != (int)slen) return SSH_ERR_INTERNAL_ERROR; if ((r = sshbuf_put_u32(m, rlen)) != 0 || (r = sshbuf_reserve(m, rlen, &p)) != 0) return r; if (cipher_get_keycontext(state->receive_context, p) != (int)rlen) return SSH_ERR_INTERNAL_ERROR; if ((r = sshbuf_put_stringb(m, state->input)) != 0 || (r = sshbuf_put_stringb(m, state->output)) != 0) return r; return 0; } /* restore key exchange results from blob for packet state de-serialization */ static int newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode) { struct sshbuf *b = NULL; struct sshcomp *comp; struct sshenc *enc; struct sshmac *mac; struct newkeys *newkey = NULL; size_t keylen, ivlen, maclen; int r; if ((newkey = calloc(1, sizeof(*newkey))) == NULL) { r = SSH_ERR_ALLOC_FAIL; goto out; } if ((r = sshbuf_froms(m, &b)) != 0) goto out; #ifdef DEBUG_PK sshbuf_dump(b, stderr); #endif enc = &newkey->enc; mac = &newkey->mac; comp = &newkey->comp; if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 || (r = sshbuf_get(b, &enc->cipher, sizeof(enc->cipher))) != 0 || (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 || (r = sshbuf_get_u32(b, &enc->block_size)) != 0 || (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 || (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0) goto out; if (cipher_authlen(enc->cipher) == 0) { if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0) goto out; if ((r = mac_setup(mac, mac->name)) != 0) goto out; if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 || (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0) goto out; if (maclen > mac->key_len) { r = SSH_ERR_INVALID_FORMAT; goto out; } mac->key_len = maclen; } if ((r = sshbuf_get_u32(b, &comp->type)) != 0 || (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0) goto out; if (enc->name == NULL || cipher_by_name(enc->name) != enc->cipher) { r = SSH_ERR_INVALID_FORMAT; goto out; } if (sshbuf_len(b) != 0) { r = SSH_ERR_INVALID_FORMAT; goto out; } enc->key_len = keylen; enc->iv_len = ivlen; ssh->kex->newkeys[mode] = newkey; newkey = NULL; r = 0; out: free(newkey); sshbuf_free(b); return r; } /* restore kex from blob for packet state de-serialization */ static int kex_from_blob(struct sshbuf *m, struct kex **kexp) { struct kex *kex; int r; if ((kex = calloc(1, sizeof(struct kex))) == NULL || (kex->my = sshbuf_new()) == NULL || (kex->peer = sshbuf_new()) == NULL) { r = SSH_ERR_ALLOC_FAIL; goto out; } if ((r = sshbuf_get_string(m, &kex->session_id, &kex->session_id_len)) != 0 || (r = sshbuf_get_u32(m, &kex->we_need)) != 0 || (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 || (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 || (r = sshbuf_get_stringb(m, kex->my)) != 0 || (r = sshbuf_get_stringb(m, kex->peer)) != 0 || (r = sshbuf_get_u32(m, &kex->flags)) != 0 || (r = sshbuf_get_cstring(m, &kex->client_version_string, NULL)) != 0 || (r = sshbuf_get_cstring(m, &kex->server_version_string, NULL)) != 0) goto out; kex->server = 1; kex->done = 1; r = 0; out: if (r != 0 || kexp == NULL) { if (kex != NULL) { sshbuf_free(kex->my); sshbuf_free(kex->peer); free(kex); } if (kexp != NULL) *kexp = NULL; } else { *kexp = kex; } return r; } /* * Restore packet state from content of blob 'm' (de-serialization). * Note that 'm' will be partially consumed on parsing or any other errors. */ int ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m) { struct session_state *state = ssh->state; const u_char *ssh1key, *ivin, *ivout, *keyin, *keyout, *input, *output; size_t ssh1keylen, rlen, slen, ilen, olen; int r; u_int ssh1cipher = 0; if (!compat20) { if ((r = sshbuf_get_u32(m, &state->remote_protocol_flags)) != 0 || (r = sshbuf_get_u32(m, &ssh1cipher)) != 0 || (r = sshbuf_get_string_direct(m, &ssh1key, &ssh1keylen)) != 0 || (r = sshbuf_get_string_direct(m, &ivout, &slen)) != 0 || (r = sshbuf_get_string_direct(m, &ivin, &rlen)) != 0) return r; if (ssh1cipher > INT_MAX) return SSH_ERR_KEY_UNKNOWN_CIPHER; ssh_packet_set_encryption_key(ssh, ssh1key, ssh1keylen, (int)ssh1cipher); if (cipher_get_keyiv_len(state->send_context) != (int)slen || cipher_get_keyiv_len(state->receive_context) != (int)rlen) return SSH_ERR_INVALID_FORMAT; if ((r = cipher_set_keyiv(state->send_context, ivout)) != 0 || (r = cipher_set_keyiv(state->receive_context, ivin)) != 0) return r; } else { if ((r = kex_from_blob(m, &ssh->kex)) != 0 || (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 || (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 || (r = sshbuf_get_u64(m, &state->rekey_limit)) != 0 || (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 || (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 || (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 || (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 || (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 || (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 || (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 || (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 || (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0) return r; /* * We set the time here so that in post-auth privsep slave we * count from the completion of the authentication. */ state->rekey_time = monotime(); /* XXX ssh_set_newkeys overrides p_read.packets? XXX */ if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 || (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0) return r; } if ((r = sshbuf_get_string_direct(m, &keyout, &slen)) != 0 || (r = sshbuf_get_string_direct(m, &keyin, &rlen)) != 0) return r; if (cipher_get_keycontext(state->send_context, NULL) != (int)slen || cipher_get_keycontext(state->receive_context, NULL) != (int)rlen) return SSH_ERR_INVALID_FORMAT; cipher_set_keycontext(state->send_context, keyout); cipher_set_keycontext(state->receive_context, keyin); if ((r = ssh_packet_set_postauth(ssh)) != 0) return r; sshbuf_reset(state->input); sshbuf_reset(state->output); if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 || (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 || (r = sshbuf_put(state->input, input, ilen)) != 0 || (r = sshbuf_put(state->output, output, olen)) != 0) return r; if (sshbuf_len(m)) return SSH_ERR_INVALID_FORMAT; debug3("%s: done", __func__); return 0; } /* NEW API */ /* put data to the outgoing packet */ int sshpkt_put(struct ssh *ssh, const void *v, size_t len) { return sshbuf_put(ssh->state->outgoing_packet, v, len); } int sshpkt_putb(struct ssh *ssh, const struct sshbuf *b) { return sshbuf_putb(ssh->state->outgoing_packet, b); } int sshpkt_put_u8(struct ssh *ssh, u_char val) { return sshbuf_put_u8(ssh->state->outgoing_packet, val); } int sshpkt_put_u32(struct ssh *ssh, u_int32_t val) { return sshbuf_put_u32(ssh->state->outgoing_packet, val); } int sshpkt_put_u64(struct ssh *ssh, u_int64_t val) { return sshbuf_put_u64(ssh->state->outgoing_packet, val); } int sshpkt_put_string(struct ssh *ssh, const void *v, size_t len) { return sshbuf_put_string(ssh->state->outgoing_packet, v, len); } int sshpkt_put_cstring(struct ssh *ssh, const void *v) { return sshbuf_put_cstring(ssh->state->outgoing_packet, v); } int sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v) { return sshbuf_put_stringb(ssh->state->outgoing_packet, v); } #ifdef WITH_OPENSSL #ifdef OPENSSL_HAS_ECC int sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g) { return sshbuf_put_ec(ssh->state->outgoing_packet, v, g); } #endif /* OPENSSL_HAS_ECC */ #ifdef WITH_SSH1 int sshpkt_put_bignum1(struct ssh *ssh, const BIGNUM *v) { return sshbuf_put_bignum1(ssh->state->outgoing_packet, v); } #endif /* WITH_SSH1 */ int sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v) { return sshbuf_put_bignum2(ssh->state->outgoing_packet, v); } #endif /* WITH_OPENSSL */ /* fetch data from the incoming packet */ int sshpkt_get(struct ssh *ssh, void *valp, size_t len) { return sshbuf_get(ssh->state->incoming_packet, valp, len); } int sshpkt_get_u8(struct ssh *ssh, u_char *valp) { return sshbuf_get_u8(ssh->state->incoming_packet, valp); } int sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp) { return sshbuf_get_u32(ssh->state->incoming_packet, valp); } int sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp) { return sshbuf_get_u64(ssh->state->incoming_packet, valp); } int sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp) { return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp); } int sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp) { return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp); } int sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp) { return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp); } #ifdef WITH_OPENSSL #ifdef OPENSSL_HAS_ECC int sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g) { return sshbuf_get_ec(ssh->state->incoming_packet, v, g); } #endif /* OPENSSL_HAS_ECC */ #ifdef WITH_SSH1 int sshpkt_get_bignum1(struct ssh *ssh, BIGNUM *v) { return sshbuf_get_bignum1(ssh->state->incoming_packet, v); } #endif /* WITH_SSH1 */ int sshpkt_get_bignum2(struct ssh *ssh, BIGNUM *v) { return sshbuf_get_bignum2(ssh->state->incoming_packet, v); } #endif /* WITH_OPENSSL */ int sshpkt_get_end(struct ssh *ssh) { if (sshbuf_len(ssh->state->incoming_packet) > 0) return SSH_ERR_UNEXPECTED_TRAILING_DATA; return 0; } const u_char * sshpkt_ptr(struct ssh *ssh, size_t *lenp) { if (lenp != NULL) *lenp = sshbuf_len(ssh->state->incoming_packet); return sshbuf_ptr(ssh->state->incoming_packet); } /* start a new packet */ int sshpkt_start(struct ssh *ssh, u_char type) { u_char buf[9]; int len; DBG(debug("packet_start[%d]", type)); len = compat20 ? 6 : 9; memset(buf, 0, len - 1); buf[len - 1] = type; sshbuf_reset(ssh->state->outgoing_packet); return sshbuf_put(ssh->state->outgoing_packet, buf, len); } static int ssh_packet_send_mux(struct ssh *ssh) { struct session_state *state = ssh->state; u_char type, *cp; size_t len; int r; if (ssh->kex) return SSH_ERR_INTERNAL_ERROR; len = sshbuf_len(state->outgoing_packet); if (len < 6) return SSH_ERR_INTERNAL_ERROR; cp = sshbuf_mutable_ptr(state->outgoing_packet); type = cp[5]; if (ssh_packet_log_type(type)) debug3("%s: type %u", __func__, type); /* drop everything, but the connection protocol */ if (type >= SSH2_MSG_CONNECTION_MIN && type <= SSH2_MSG_CONNECTION_MAX) { POKE_U32(cp, len - 4); if ((r = sshbuf_putb(state->output, state->outgoing_packet)) != 0) return r; /* sshbuf_dump(state->output, stderr); */ } sshbuf_reset(state->outgoing_packet); return 0; } /* send it */ int sshpkt_send(struct ssh *ssh) { if (ssh->state && ssh->state->mux) return ssh_packet_send_mux(ssh); if (compat20) return ssh_packet_send2(ssh); else return ssh_packet_send1(ssh); } int sshpkt_disconnect(struct ssh *ssh, const char *fmt,...) { char buf[1024]; va_list args; int r; va_start(args, fmt); vsnprintf(buf, sizeof(buf), fmt, args); va_end(args); if (compat20) { if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 || (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 || (r = sshpkt_put_cstring(ssh, buf)) != 0 || (r = sshpkt_put_cstring(ssh, "")) != 0 || (r = sshpkt_send(ssh)) != 0) return r; } else { if ((r = sshpkt_start(ssh, SSH_MSG_DISCONNECT)) != 0 || (r = sshpkt_put_cstring(ssh, buf)) != 0 || (r = sshpkt_send(ssh)) != 0) return r; } return 0; } /* roundup current message to pad bytes */ int sshpkt_add_padding(struct ssh *ssh, u_char pad) { ssh->state->extra_pad = pad; return 0; } diff --git a/crypto/openssh/sshd.c b/crypto/openssh/sshd.c index 57090d6d51a0..50d3701e78b2 100644 --- a/crypto/openssh/sshd.c +++ b/crypto/openssh/sshd.c @@ -1,2296 +1,2296 @@ /* $OpenBSD: sshd.c,v 1.480 2016/12/09 03:04:29 djm Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland * All rights reserved * This program is the ssh daemon. It listens for connections from clients, * and performs authentication, executes use commands or shell, and forwards * information to/from the application to the user client over an encrypted * connection. This can also handle forwarding of X11, TCP/IP, and * authentication agent connections. * * As far as I am concerned, the code I have written for this software * can be used freely for any purpose. Any derived versions of this * software must be clearly marked as such, and if the derived work is * incompatible with the protocol description in the RFC file, it must be * called by a name other than "ssh" or "Secure Shell". * * SSH2 implementation: * Privilege Separation: * * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved. * Copyright (c) 2002 Niels Provos. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include "includes.h" __RCSID("$FreeBSD$"); #include #include #include #include #ifdef HAVE_SYS_STAT_H # include #endif #ifdef HAVE_SYS_TIME_H # include #endif #include "openbsd-compat/sys-tree.h" #include "openbsd-compat/sys-queue.h" #include #include #include #include #ifdef HAVE_PATHS_H #include #endif #include #include #include #include #include #include #include #include #include #ifdef WITH_OPENSSL #include #include #include #include "openbsd-compat/openssl-compat.h" #endif #ifdef HAVE_SECUREWARE #include #include #endif #ifdef __FreeBSD__ #include #if defined(GSSAPI) && defined(HAVE_GSSAPI_GSSAPI_H) #include #elif defined(GSSAPI) && defined(HAVE_GSSAPI_H) #include #endif #endif #include "xmalloc.h" #include "ssh.h" #include "ssh2.h" #include "rsa.h" #include "sshpty.h" #include "packet.h" #include "log.h" #include "buffer.h" #include "misc.h" #include "match.h" #include "servconf.h" #include "uidswap.h" #include "compat.h" #include "cipher.h" #include "digest.h" #include "key.h" #include "kex.h" #include "myproposal.h" #include "authfile.h" #include "pathnames.h" #include "atomicio.h" #include "canohost.h" #include "hostfile.h" #include "auth.h" #include "authfd.h" #include "msg.h" #include "dispatch.h" #include "channels.h" #include "session.h" #include "monitor.h" #ifdef GSSAPI #include "ssh-gss.h" #endif #include "monitor_wrap.h" #include "ssh-sandbox.h" #include "version.h" #include "ssherr.h" #include "blacklist_client.h" #ifdef LIBWRAP #include #include int allow_severity; int deny_severity; #endif /* LIBWRAP */ /* Re-exec fds */ #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) extern char *__progname; /* Server configuration options. */ ServerOptions options; /* Name of the server configuration file. */ char *config_file_name = _PATH_SERVER_CONFIG_FILE; /* * Debug mode flag. This can be set on the command line. If debug * mode is enabled, extra debugging output will be sent to the system * log, the daemon will not go to background, and will exit after processing * the first connection. */ int debug_flag = 0; /* Flag indicating that the daemon should only test the configuration and keys. */ int test_flag = 0; /* Flag indicating that the daemon is being started from inetd. */ int inetd_flag = 0; /* Flag indicating that sshd should not detach and become a daemon. */ int no_daemon_flag = 0; /* debug goes to stderr unless inetd_flag is set */ int log_stderr = 0; /* Saved arguments to main(). */ char **saved_argv; int saved_argc; /* re-exec */ int rexeced_flag = 0; int rexec_flag = 1; int rexec_argc = 0; char **rexec_argv; /* * The sockets that the server is listening; this is used in the SIGHUP * signal handler. */ #define MAX_LISTEN_SOCKS 16 int listen_socks[MAX_LISTEN_SOCKS]; int num_listen_socks = 0; /* * the client's version string, passed by sshd2 in compat mode. if != NULL, * sshd will skip the version-number exchange */ char *client_version_string = NULL; char *server_version_string = NULL; /* Daemon's agent connection */ int auth_sock = -1; int have_agent = 0; /* * Any really sensitive data in the application is contained in this * structure. The idea is that this structure could be locked into memory so * that the pages do not get written into swap. However, there are some * problems. The private key contains BIGNUMs, and we do not (in principle) * have access to the internals of them, and locking just the structure is * not very useful. Currently, memory locking is not implemented. */ struct { Key **host_keys; /* all private host keys */ Key **host_pubkeys; /* all public host keys */ Key **host_certificates; /* all public host certificates */ int have_ssh2_key; } sensitive_data; /* This is set to true when a signal is received. */ static volatile sig_atomic_t received_sighup = 0; static volatile sig_atomic_t received_sigterm = 0; /* session identifier, used by RSA-auth */ u_char session_id[16]; /* same for ssh2 */ u_char *session_id2 = NULL; u_int session_id2_len = 0; /* record remote hostname or ip */ u_int utmp_len = HOST_NAME_MAX+1; /* options.max_startup sized array of fd ints */ int *startup_pipes = NULL; int startup_pipe; /* in child */ /* variables used for privilege separation */ int use_privsep = -1; struct monitor *pmonitor = NULL; int privsep_is_preauth = 1; /* global authentication context */ Authctxt *the_authctxt = NULL; /* sshd_config buffer */ Buffer cfg; /* message to be displayed after login */ Buffer loginmsg; /* Unprivileged user */ struct passwd *privsep_pw = NULL; /* Prototypes for various functions defined later in this file. */ void destroy_sensitive_data(void); void demote_sensitive_data(void); static void do_ssh2_kex(void); /* * Close all listening sockets */ static void close_listen_socks(void) { int i; for (i = 0; i < num_listen_socks; i++) close(listen_socks[i]); num_listen_socks = -1; } static void close_startup_pipes(void) { int i; if (startup_pipes) for (i = 0; i < options.max_startups; i++) if (startup_pipes[i] != -1) close(startup_pipes[i]); } /* * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; * the effect is to reread the configuration file (and to regenerate * the server key). */ /*ARGSUSED*/ static void sighup_handler(int sig) { int save_errno = errno; received_sighup = 1; signal(SIGHUP, sighup_handler); errno = save_errno; } /* * Called from the main program after receiving SIGHUP. * Restarts the server. */ static void sighup_restart(void) { logit("Received SIGHUP; restarting."); if (options.pid_file != NULL) unlink(options.pid_file); platform_pre_restart(); close_listen_socks(); close_startup_pipes(); alarm(0); /* alarm timer persists across exec */ signal(SIGHUP, SIG_IGN); /* will be restored after exec */ execv(saved_argv[0], saved_argv); logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], strerror(errno)); exit(1); } /* * Generic signal handler for terminating signals in the master daemon. */ /*ARGSUSED*/ static void sigterm_handler(int sig) { received_sigterm = sig; } /* * SIGCHLD handler. This is called whenever a child dies. This will then * reap any zombies left by exited children. */ /*ARGSUSED*/ static void main_sigchld_handler(int sig) { int save_errno = errno; pid_t pid; int status; while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || (pid < 0 && errno == EINTR)) ; signal(SIGCHLD, main_sigchld_handler); errno = save_errno; } /* * Signal handler for the alarm after the login grace period has expired. */ /*ARGSUSED*/ static void grace_alarm_handler(int sig) { if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) kill(pmonitor->m_pid, SIGALRM); /* * Try to kill any processes that we have spawned, E.g. authorized * keys command helpers. */ if (getpgid(0) == getpid()) { signal(SIGTERM, SIG_IGN); kill(0, SIGTERM); } - BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL); + BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL, "ssh"); /* Log error and exit. */ sigdie("Timeout before authentication for %s port %d", ssh_remote_ipaddr(active_state), ssh_remote_port(active_state)); } static void sshd_exchange_identification(struct ssh *ssh, int sock_in, int sock_out) { u_int i; int remote_major, remote_minor; char *s, *newline = "\n"; char buf[256]; /* Must not be larger than remote_version. */ char remote_version[256]; /* Must be at least as big as buf. */ xasprintf(&server_version_string, "SSH-%d.%d-%.100s%s%s%s", PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, SSH_VERSION, *options.version_addendum == '\0' ? "" : " ", options.version_addendum, newline); /* Send our protocol version identification. */ if (atomicio(vwrite, sock_out, server_version_string, strlen(server_version_string)) != strlen(server_version_string)) { logit("Could not write ident string to %s port %d", ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); cleanup_exit(255); } /* Read other sides version identification. */ memset(buf, 0, sizeof(buf)); for (i = 0; i < sizeof(buf) - 1; i++) { if (atomicio(read, sock_in, &buf[i], 1) != 1) { logit("Did not receive identification string " "from %s port %d", ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); cleanup_exit(255); } if (buf[i] == '\r') { buf[i] = 0; /* Kludge for F-Secure Macintosh < 1.0.2 */ if (i == 12 && strncmp(buf, "SSH-1.5-W1.0", 12) == 0) break; continue; } if (buf[i] == '\n') { buf[i] = 0; break; } } buf[sizeof(buf) - 1] = 0; client_version_string = xstrdup(buf); /* * Check that the versions match. In future this might accept * several versions and set appropriate flags to handle them. */ if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor, remote_version) != 3) { s = "Protocol mismatch.\n"; (void) atomicio(vwrite, sock_out, s, strlen(s)); logit("Bad protocol version identification '%.100s' " "from %s port %d", client_version_string, ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); close(sock_in); close(sock_out); cleanup_exit(255); } debug("Client protocol version %d.%d; client software version %.100s", remote_major, remote_minor, remote_version); ssh->compat = compat_datafellows(remote_version); if ((ssh->compat & SSH_BUG_PROBE) != 0) { logit("probed from %s port %d with %s. Don't panic.", ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), client_version_string); cleanup_exit(255); } if ((ssh->compat & SSH_BUG_SCANNER) != 0) { logit("scanned from %s port %d with %s. Don't panic.", ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), client_version_string); cleanup_exit(255); } if ((ssh->compat & SSH_BUG_RSASIGMD5) != 0) { logit("Client version \"%.100s\" uses unsafe RSA signature " "scheme; disabling use of RSA keys", remote_version); } if ((ssh->compat & SSH_BUG_DERIVEKEY) != 0) { fatal("Client version \"%.100s\" uses unsafe key agreement; " "refusing connection", remote_version); } chop(server_version_string); debug("Local version string %.200s", server_version_string); if (remote_major == 2 || (remote_major == 1 && remote_minor == 99)) { enable_compat20(); } else { s = "Protocol major versions differ.\n"; (void) atomicio(vwrite, sock_out, s, strlen(s)); close(sock_in); close(sock_out); logit("Protocol major versions differ for %s port %d: " "%.200s vs. %.200s", ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), server_version_string, client_version_string); cleanup_exit(255); } } /* Destroy the host and server keys. They will no longer be needed. */ void destroy_sensitive_data(void) { int i; for (i = 0; i < options.num_host_key_files; i++) { if (sensitive_data.host_keys[i]) { key_free(sensitive_data.host_keys[i]); sensitive_data.host_keys[i] = NULL; } if (sensitive_data.host_certificates[i]) { key_free(sensitive_data.host_certificates[i]); sensitive_data.host_certificates[i] = NULL; } } } /* Demote private to public keys for network child */ void demote_sensitive_data(void) { Key *tmp; int i; for (i = 0; i < options.num_host_key_files; i++) { if (sensitive_data.host_keys[i]) { tmp = key_demote(sensitive_data.host_keys[i]); key_free(sensitive_data.host_keys[i]); sensitive_data.host_keys[i] = tmp; } /* Certs do not need demotion */ } } static void reseed_prngs(void) { u_int32_t rnd[256]; #ifdef WITH_OPENSSL RAND_poll(); #endif arc4random_stir(); /* noop on recent arc4random() implementations */ arc4random_buf(rnd, sizeof(rnd)); /* let arc4random notice PID change */ #ifdef WITH_OPENSSL RAND_seed(rnd, sizeof(rnd)); /* give libcrypto a chance to notice the PID change */ if ((RAND_bytes((u_char *)rnd, 1)) != 1) fatal("%s: RAND_bytes failed", __func__); #endif explicit_bzero(rnd, sizeof(rnd)); } static void privsep_preauth_child(void) { gid_t gidset[1]; /* Enable challenge-response authentication for privilege separation */ privsep_challenge_enable(); #ifdef GSSAPI /* Cache supported mechanism OIDs for later use */ if (options.gss_authentication) ssh_gssapi_prepare_supported_oids(); #endif reseed_prngs(); /* Demote the private keys to public keys. */ demote_sensitive_data(); /* Demote the child */ if (getuid() == 0 || geteuid() == 0) { /* Change our root directory */ if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, strerror(errno)); if (chdir("/") == -1) fatal("chdir(\"/\"): %s", strerror(errno)); /* Drop our privileges */ debug3("privsep user:group %u:%u", (u_int)privsep_pw->pw_uid, (u_int)privsep_pw->pw_gid); gidset[0] = privsep_pw->pw_gid; if (setgroups(1, gidset) < 0) fatal("setgroups: %.100s", strerror(errno)); permanently_set_uid(privsep_pw); } } static int privsep_preauth(Authctxt *authctxt) { int status, r; pid_t pid; struct ssh_sandbox *box = NULL; /* Set up unprivileged child process to deal with network data */ pmonitor = monitor_init(); /* Store a pointer to the kex for later rekeying */ pmonitor->m_pkex = &active_state->kex; if (use_privsep == PRIVSEP_ON) box = ssh_sandbox_init(pmonitor); pid = fork(); if (pid == -1) { fatal("fork of unprivileged child failed"); } else if (pid != 0) { debug2("Network child is on pid %ld", (long)pid); pmonitor->m_pid = pid; if (have_agent) { r = ssh_get_authentication_socket(&auth_sock); if (r != 0) { error("Could not get agent socket: %s", ssh_err(r)); have_agent = 0; } } if (box != NULL) ssh_sandbox_parent_preauth(box, pid); monitor_child_preauth(authctxt, pmonitor); /* Wait for the child's exit status */ while (waitpid(pid, &status, 0) < 0) { if (errno == EINTR) continue; pmonitor->m_pid = -1; fatal("%s: waitpid: %s", __func__, strerror(errno)); } privsep_is_preauth = 0; pmonitor->m_pid = -1; if (WIFEXITED(status)) { if (WEXITSTATUS(status) != 0) fatal("%s: preauth child exited with status %d", __func__, WEXITSTATUS(status)); } else if (WIFSIGNALED(status)) fatal("%s: preauth child terminated by signal %d", __func__, WTERMSIG(status)); if (box != NULL) ssh_sandbox_parent_finish(box); return 1; } else { /* child */ close(pmonitor->m_sendfd); close(pmonitor->m_log_recvfd); /* Arrange for logging to be sent to the monitor */ set_log_handler(mm_log_handler, pmonitor); privsep_preauth_child(); setproctitle("%s", "[net]"); if (box != NULL) ssh_sandbox_child(box); return 0; } } static void privsep_postauth(Authctxt *authctxt) { #ifdef DISABLE_FD_PASSING if (1) { #else if (authctxt->pw->pw_uid == 0) { #endif /* File descriptor passing is broken or root login */ use_privsep = 0; goto skip; } /* New socket pair */ monitor_reinit(pmonitor); pmonitor->m_pid = fork(); if (pmonitor->m_pid == -1) fatal("fork of unprivileged child failed"); else if (pmonitor->m_pid != 0) { verbose("User child is on pid %ld", (long)pmonitor->m_pid); buffer_clear(&loginmsg); monitor_child_postauth(pmonitor); /* NEVERREACHED */ exit(0); } /* child */ close(pmonitor->m_sendfd); pmonitor->m_sendfd = -1; /* Demote the private keys to public keys. */ demote_sensitive_data(); reseed_prngs(); /* Drop privileges */ do_setusercontext(authctxt->pw); skip: /* It is safe now to apply the key state */ monitor_apply_keystate(pmonitor); /* * Tell the packet layer that authentication was successful, since * this information is not part of the key state. */ packet_set_authenticated(); } static char * list_hostkey_types(void) { Buffer b; const char *p; char *ret; int i; Key *key; buffer_init(&b); for (i = 0; i < options.num_host_key_files; i++) { key = sensitive_data.host_keys[i]; if (key == NULL) key = sensitive_data.host_pubkeys[i]; if (key == NULL) continue; /* Check that the key is accepted in HostkeyAlgorithms */ if (match_pattern_list(sshkey_ssh_name(key), options.hostkeyalgorithms, 0) != 1) { debug3("%s: %s key not permitted by HostkeyAlgorithms", __func__, sshkey_ssh_name(key)); continue; } switch (key->type) { case KEY_RSA: case KEY_DSA: case KEY_ECDSA: case KEY_ED25519: if (buffer_len(&b) > 0) buffer_append(&b, ",", 1); p = key_ssh_name(key); buffer_append(&b, p, strlen(p)); /* for RSA we also support SHA2 signatures */ if (key->type == KEY_RSA) { p = ",rsa-sha2-512,rsa-sha2-256"; buffer_append(&b, p, strlen(p)); } break; } /* If the private key has a cert peer, then list that too */ key = sensitive_data.host_certificates[i]; if (key == NULL) continue; switch (key->type) { case KEY_RSA_CERT: case KEY_DSA_CERT: case KEY_ECDSA_CERT: case KEY_ED25519_CERT: if (buffer_len(&b) > 0) buffer_append(&b, ",", 1); p = key_ssh_name(key); buffer_append(&b, p, strlen(p)); break; } } if ((ret = sshbuf_dup_string(&b)) == NULL) fatal("%s: sshbuf_dup_string failed", __func__); buffer_free(&b); debug("list_hostkey_types: %s", ret); return ret; } static Key * get_hostkey_by_type(int type, int nid, int need_private, struct ssh *ssh) { int i; Key *key; for (i = 0; i < options.num_host_key_files; i++) { switch (type) { case KEY_RSA_CERT: case KEY_DSA_CERT: case KEY_ECDSA_CERT: case KEY_ED25519_CERT: key = sensitive_data.host_certificates[i]; break; default: key = sensitive_data.host_keys[i]; if (key == NULL && !need_private) key = sensitive_data.host_pubkeys[i]; break; } if (key != NULL && key->type == type && (key->type != KEY_ECDSA || key->ecdsa_nid == nid)) return need_private ? sensitive_data.host_keys[i] : key; } return NULL; } Key * get_hostkey_public_by_type(int type, int nid, struct ssh *ssh) { return get_hostkey_by_type(type, nid, 0, ssh); } Key * get_hostkey_private_by_type(int type, int nid, struct ssh *ssh) { return get_hostkey_by_type(type, nid, 1, ssh); } Key * get_hostkey_by_index(int ind) { if (ind < 0 || ind >= options.num_host_key_files) return (NULL); return (sensitive_data.host_keys[ind]); } Key * get_hostkey_public_by_index(int ind, struct ssh *ssh) { if (ind < 0 || ind >= options.num_host_key_files) return (NULL); return (sensitive_data.host_pubkeys[ind]); } int get_hostkey_index(Key *key, int compare, struct ssh *ssh) { int i; for (i = 0; i < options.num_host_key_files; i++) { if (key_is_cert(key)) { if (key == sensitive_data.host_certificates[i] || (compare && sensitive_data.host_certificates[i] && sshkey_equal(key, sensitive_data.host_certificates[i]))) return (i); } else { if (key == sensitive_data.host_keys[i] || (compare && sensitive_data.host_keys[i] && sshkey_equal(key, sensitive_data.host_keys[i]))) return (i); if (key == sensitive_data.host_pubkeys[i] || (compare && sensitive_data.host_pubkeys[i] && sshkey_equal(key, sensitive_data.host_pubkeys[i]))) return (i); } } return (-1); } /* Inform the client of all hostkeys */ static void notify_hostkeys(struct ssh *ssh) { struct sshbuf *buf; struct sshkey *key; int i, nkeys, r; char *fp; /* Some clients cannot cope with the hostkeys message, skip those. */ if (datafellows & SSH_BUG_HOSTKEYS) return; if ((buf = sshbuf_new()) == NULL) fatal("%s: sshbuf_new", __func__); for (i = nkeys = 0; i < options.num_host_key_files; i++) { key = get_hostkey_public_by_index(i, ssh); if (key == NULL || key->type == KEY_UNSPEC || sshkey_is_cert(key)) continue; fp = sshkey_fingerprint(key, options.fingerprint_hash, SSH_FP_DEFAULT); debug3("%s: key %d: %s %s", __func__, i, sshkey_ssh_name(key), fp); free(fp); if (nkeys == 0) { packet_start(SSH2_MSG_GLOBAL_REQUEST); packet_put_cstring("hostkeys-00@openssh.com"); packet_put_char(0); /* want-reply */ } sshbuf_reset(buf); if ((r = sshkey_putb(key, buf)) != 0) fatal("%s: couldn't put hostkey %d: %s", __func__, i, ssh_err(r)); packet_put_string(sshbuf_ptr(buf), sshbuf_len(buf)); nkeys++; } debug3("%s: sent %d hostkeys", __func__, nkeys); if (nkeys == 0) fatal("%s: no hostkeys", __func__); packet_send(); sshbuf_free(buf); } /* * returns 1 if connection should be dropped, 0 otherwise. * dropping starts at connection #max_startups_begin with a probability * of (max_startups_rate/100). the probability increases linearly until * all connections are dropped for startups > max_startups */ static int drop_connection(int startups) { int p, r; if (startups < options.max_startups_begin) return 0; if (startups >= options.max_startups) return 1; if (options.max_startups_rate == 100) return 1; p = 100 - options.max_startups_rate; p *= startups - options.max_startups_begin; p /= options.max_startups - options.max_startups_begin; p += options.max_startups_rate; r = arc4random_uniform(100); debug("drop_connection: p %d, r %d", p, r); return (r < p) ? 1 : 0; } static void usage(void) { if (options.version_addendum && *options.version_addendum != '\0') fprintf(stderr, "%s %s, %s\n", SSH_RELEASE, options.version_addendum, OPENSSL_VERSION); else fprintf(stderr, "%s, %s\n", SSH_RELEASE, OPENSSL_VERSION); fprintf(stderr, "usage: sshd [-46DdeiqTt] [-C connection_spec] [-c host_cert_file]\n" " [-E log_file] [-f config_file] [-g login_grace_time]\n" " [-h host_key_file] [-o option] [-p port] [-u len]\n" ); exit(1); } static void send_rexec_state(int fd, struct sshbuf *conf) { struct sshbuf *m; int r; debug3("%s: entering fd = %d config len %zu", __func__, fd, sshbuf_len(conf)); /* * Protocol from reexec master to child: * string configuration * string rngseed (only if OpenSSL is not self-seeded) */ if ((m = sshbuf_new()) == NULL) fatal("%s: sshbuf_new failed", __func__); if ((r = sshbuf_put_stringb(m, conf)) != 0) fatal("%s: buffer error: %s", __func__, ssh_err(r)); #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY) rexec_send_rng_seed(m); #endif if (ssh_msg_send(fd, 0, m) == -1) fatal("%s: ssh_msg_send failed", __func__); sshbuf_free(m); debug3("%s: done", __func__); } static void recv_rexec_state(int fd, Buffer *conf) { Buffer m; char *cp; u_int len; debug3("%s: entering fd = %d", __func__, fd); buffer_init(&m); if (ssh_msg_recv(fd, &m) == -1) fatal("%s: ssh_msg_recv failed", __func__); if (buffer_get_char(&m) != 0) fatal("%s: rexec version mismatch", __func__); cp = buffer_get_string(&m, &len); if (conf != NULL) buffer_append(conf, cp, len); free(cp); #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY) rexec_recv_rng_seed(&m); #endif buffer_free(&m); debug3("%s: done", __func__); } /* Accept a connection from inetd */ static void server_accept_inetd(int *sock_in, int *sock_out) { int fd; startup_pipe = -1; if (rexeced_flag) { close(REEXEC_CONFIG_PASS_FD); *sock_in = *sock_out = dup(STDIN_FILENO); if (!debug_flag) { startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); close(REEXEC_STARTUP_PIPE_FD); } } else { *sock_in = dup(STDIN_FILENO); *sock_out = dup(STDOUT_FILENO); } /* * We intentionally do not close the descriptors 0, 1, and 2 * as our code for setting the descriptors won't work if * ttyfd happens to be one of those. */ if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { dup2(fd, STDIN_FILENO); dup2(fd, STDOUT_FILENO); if (!log_stderr) dup2(fd, STDERR_FILENO); if (fd > (log_stderr ? STDERR_FILENO : STDOUT_FILENO)) close(fd); } debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out); } /* * Listen for TCP connections */ static void server_listen(void) { int ret, listen_sock, on = 1; struct addrinfo *ai; char ntop[NI_MAXHOST], strport[NI_MAXSERV]; int socksize; socklen_t len; for (ai = options.listen_addrs; ai; ai = ai->ai_next) { if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) continue; if (num_listen_socks >= MAX_LISTEN_SOCKS) fatal("Too many listen sockets. " "Enlarge MAX_LISTEN_SOCKS"); if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { error("getnameinfo failed: %.100s", ssh_gai_strerror(ret)); continue; } /* Create socket for listening. */ listen_sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); if (listen_sock < 0) { /* kernel may not support ipv6 */ verbose("socket: %.100s", strerror(errno)); continue; } if (set_nonblock(listen_sock) == -1) { close(listen_sock); continue; } /* * Set socket options. * Allow local port reuse in TIME_WAIT. */ if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1) error("setsockopt SO_REUSEADDR: %s", strerror(errno)); /* Only communicate in IPv6 over AF_INET6 sockets. */ if (ai->ai_family == AF_INET6) sock_set_v6only(listen_sock); debug("Bind to port %s on %s.", strport, ntop); len = sizeof(socksize); getsockopt(listen_sock, SOL_SOCKET, SO_RCVBUF, &socksize, &len); debug("Server TCP RWIN socket size: %d", socksize); /* Bind the socket to the desired port. */ if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { error("Bind to port %s on %s failed: %.200s.", strport, ntop, strerror(errno)); close(listen_sock); continue; } listen_socks[num_listen_socks] = listen_sock; num_listen_socks++; /* Start listening on the port. */ if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) fatal("listen on [%s]:%s: %.100s", ntop, strport, strerror(errno)); logit("Server listening on %s port %s.", ntop, strport); } freeaddrinfo(options.listen_addrs); if (!num_listen_socks) fatal("Cannot bind any address."); } /* * The main TCP accept loop. Note that, for the non-debug case, returns * from this function are in a forked subprocess. */ static void server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s) { fd_set *fdset; int i, j, ret, maxfd; int startups = 0; int startup_p[2] = { -1 , -1 }; struct sockaddr_storage from; socklen_t fromlen; pid_t pid; u_char rnd[256]; /* setup fd set for accept */ fdset = NULL; maxfd = 0; for (i = 0; i < num_listen_socks; i++) if (listen_socks[i] > maxfd) maxfd = listen_socks[i]; /* pipes connected to unauthenticated childs */ startup_pipes = xcalloc(options.max_startups, sizeof(int)); for (i = 0; i < options.max_startups; i++) startup_pipes[i] = -1; /* * Stay listening for connections until the system crashes or * the daemon is killed with a signal. */ for (;;) { if (received_sighup) sighup_restart(); free(fdset); fdset = xcalloc(howmany(maxfd + 1, NFDBITS), sizeof(fd_mask)); for (i = 0; i < num_listen_socks; i++) FD_SET(listen_socks[i], fdset); for (i = 0; i < options.max_startups; i++) if (startup_pipes[i] != -1) FD_SET(startup_pipes[i], fdset); /* Wait in select until there is a connection. */ ret = select(maxfd+1, fdset, NULL, NULL, NULL); if (ret < 0 && errno != EINTR) error("select: %.100s", strerror(errno)); if (received_sigterm) { logit("Received signal %d; terminating.", (int) received_sigterm); close_listen_socks(); if (options.pid_file != NULL) unlink(options.pid_file); exit(received_sigterm == SIGTERM ? 0 : 255); } if (ret < 0) continue; for (i = 0; i < options.max_startups; i++) if (startup_pipes[i] != -1 && FD_ISSET(startup_pipes[i], fdset)) { /* * the read end of the pipe is ready * if the child has closed the pipe * after successful authentication * or if the child has died */ close(startup_pipes[i]); startup_pipes[i] = -1; startups--; } for (i = 0; i < num_listen_socks; i++) { if (!FD_ISSET(listen_socks[i], fdset)) continue; fromlen = sizeof(from); *newsock = accept(listen_socks[i], (struct sockaddr *)&from, &fromlen); if (*newsock < 0) { if (errno != EINTR && errno != EWOULDBLOCK && errno != ECONNABORTED && errno != EAGAIN) error("accept: %.100s", strerror(errno)); if (errno == EMFILE || errno == ENFILE) usleep(100 * 1000); continue; } if (unset_nonblock(*newsock) == -1) { close(*newsock); continue; } if (drop_connection(startups) == 1) { char *laddr = get_local_ipaddr(*newsock); char *raddr = get_peer_ipaddr(*newsock); verbose("drop connection #%d from [%s]:%d " "on [%s]:%d past MaxStartups", startups, raddr, get_peer_port(*newsock), laddr, get_local_port(*newsock)); free(laddr); free(raddr); close(*newsock); continue; } if (pipe(startup_p) == -1) { close(*newsock); continue; } if (rexec_flag && socketpair(AF_UNIX, SOCK_STREAM, 0, config_s) == -1) { error("reexec socketpair: %s", strerror(errno)); close(*newsock); close(startup_p[0]); close(startup_p[1]); continue; } for (j = 0; j < options.max_startups; j++) if (startup_pipes[j] == -1) { startup_pipes[j] = startup_p[0]; if (maxfd < startup_p[0]) maxfd = startup_p[0]; startups++; break; } /* * Got connection. Fork a child to handle it, unless * we are in debugging mode. */ if (debug_flag) { /* * In debugging mode. Close the listening * socket, and start processing the * connection without forking. */ debug("Server will not fork when running in debugging mode."); close_listen_socks(); *sock_in = *newsock; *sock_out = *newsock; close(startup_p[0]); close(startup_p[1]); startup_pipe = -1; pid = getpid(); if (rexec_flag) { send_rexec_state(config_s[0], &cfg); close(config_s[0]); } break; } /* * Normal production daemon. Fork, and have * the child process the connection. The * parent continues listening. */ platform_pre_fork(); if ((pid = fork()) == 0) { /* * Child. Close the listening and * max_startup sockets. Start using * the accepted socket. Reinitialize * logging (since our pid has changed). * We break out of the loop to handle * the connection. */ platform_post_fork_child(); startup_pipe = startup_p[1]; close_startup_pipes(); close_listen_socks(); *sock_in = *newsock; *sock_out = *newsock; log_init(__progname, options.log_level, options.log_facility, log_stderr); if (rexec_flag) close(config_s[0]); break; } /* Parent. Stay in the loop. */ platform_post_fork_parent(pid); if (pid < 0) error("fork: %.100s", strerror(errno)); else debug("Forked child %ld.", (long)pid); close(startup_p[1]); if (rexec_flag) { send_rexec_state(config_s[0], &cfg); close(config_s[0]); close(config_s[1]); } close(*newsock); /* * Ensure that our random state differs * from that of the child */ arc4random_stir(); arc4random_buf(rnd, sizeof(rnd)); #ifdef WITH_OPENSSL RAND_seed(rnd, sizeof(rnd)); if ((RAND_bytes((u_char *)rnd, 1)) != 1) fatal("%s: RAND_bytes failed", __func__); #endif explicit_bzero(rnd, sizeof(rnd)); } /* child process check (or debug mode) */ if (num_listen_socks < 0) break; } } /* * If IP options are supported, make sure there are none (log and * return an error if any are found). Basically we are worried about * source routing; it can be used to pretend you are somebody * (ip-address) you are not. That itself may be "almost acceptable" * under certain circumstances, but rhosts autentication is useless * if source routing is accepted. Notice also that if we just dropped * source routing here, the other side could use IP spoofing to do * rest of the interaction and could still bypass security. So we * exit here if we detect any IP options. */ static void check_ip_options(struct ssh *ssh) { #ifdef IP_OPTIONS int sock_in = ssh_packet_get_connection_in(ssh); struct sockaddr_storage from; u_char opts[200]; socklen_t i, option_size = sizeof(opts), fromlen = sizeof(from); char text[sizeof(opts) * 3 + 1]; memset(&from, 0, sizeof(from)); if (getpeername(sock_in, (struct sockaddr *)&from, &fromlen) < 0) return; if (from.ss_family != AF_INET) return; /* XXX IPv6 options? */ if (getsockopt(sock_in, IPPROTO_IP, IP_OPTIONS, opts, &option_size) >= 0 && option_size != 0) { text[0] = '\0'; for (i = 0; i < option_size; i++) snprintf(text + i*3, sizeof(text) - i*3, " %2.2x", opts[i]); fatal("Connection from %.100s port %d with IP opts: %.800s", ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), text); } return; #endif /* IP_OPTIONS */ } /* * Main program for the daemon. */ int main(int ac, char **av) { struct ssh *ssh = NULL; extern char *optarg; extern int optind; int r, opt, i, j, on = 1, already_daemon; int sock_in = -1, sock_out = -1, newsock = -1; const char *remote_ip; int remote_port; char *fp, *line, *laddr, *logfile = NULL; int config_s[2] = { -1 , -1 }; u_int n; u_int64_t ibytes, obytes; mode_t new_umask; Key *key; Key *pubkey; int keytype; Authctxt *authctxt; struct connection_info *connection_info = get_connection_info(0, 0); ssh_malloc_init(); /* must be called before any mallocs */ #ifdef HAVE_SECUREWARE (void)set_auth_parameters(ac, av); #endif __progname = ssh_get_progname(av[0]); /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ saved_argc = ac; rexec_argc = ac; saved_argv = xcalloc(ac + 1, sizeof(*saved_argv)); for (i = 0; i < ac; i++) saved_argv[i] = xstrdup(av[i]); saved_argv[i] = NULL; #ifndef HAVE_SETPROCTITLE /* Prepare for later setproctitle emulation */ compat_init_setproctitle(ac, av); av = saved_argv; #endif if (geteuid() == 0 && setgroups(0, NULL) == -1) debug("setgroups(): %.200s", strerror(errno)); /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ sanitise_stdfd(); /* Initialize configuration options to their default values. */ initialize_server_options(&options); /* Parse command-line arguments. */ while ((opt = getopt(ac, av, "C:E:b:c:f:g:h:k:o:p:u:46DQRTdeiqrt")) != -1) { switch (opt) { case '4': options.address_family = AF_INET; break; case '6': options.address_family = AF_INET6; break; case 'f': config_file_name = optarg; break; case 'c': if (options.num_host_cert_files >= MAX_HOSTCERTS) { fprintf(stderr, "too many host certificates.\n"); exit(1); } options.host_cert_files[options.num_host_cert_files++] = derelativise_path(optarg); break; case 'd': if (debug_flag == 0) { debug_flag = 1; options.log_level = SYSLOG_LEVEL_DEBUG1; } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) options.log_level++; break; case 'D': no_daemon_flag = 1; break; case 'E': logfile = optarg; /* FALLTHROUGH */ case 'e': log_stderr = 1; break; case 'i': inetd_flag = 1; break; case 'r': rexec_flag = 0; break; case 'R': rexeced_flag = 1; inetd_flag = 1; break; case 'Q': /* ignored */ break; case 'q': options.log_level = SYSLOG_LEVEL_QUIET; break; case 'b': /* protocol 1, ignored */ break; case 'p': options.ports_from_cmdline = 1; if (options.num_ports >= MAX_PORTS) { fprintf(stderr, "too many ports.\n"); exit(1); } options.ports[options.num_ports++] = a2port(optarg); if (options.ports[options.num_ports-1] <= 0) { fprintf(stderr, "Bad port number.\n"); exit(1); } break; case 'g': if ((options.login_grace_time = convtime(optarg)) == -1) { fprintf(stderr, "Invalid login grace time.\n"); exit(1); } break; case 'k': /* protocol 1, ignored */ break; case 'h': if (options.num_host_key_files >= MAX_HOSTKEYS) { fprintf(stderr, "too many host keys.\n"); exit(1); } options.host_key_files[options.num_host_key_files++] = derelativise_path(optarg); break; case 't': test_flag = 1; break; case 'T': test_flag = 2; break; case 'C': if (parse_server_match_testspec(connection_info, optarg) == -1) exit(1); break; case 'u': utmp_len = (u_int)strtonum(optarg, 0, HOST_NAME_MAX+1+1, NULL); if (utmp_len > HOST_NAME_MAX+1) { fprintf(stderr, "Invalid utmp length.\n"); exit(1); } break; case 'o': line = xstrdup(optarg); if (process_server_config_line(&options, line, "command-line", 0, NULL, NULL) != 0) exit(1); free(line); break; case '?': default: usage(); break; } } if (rexeced_flag || inetd_flag) rexec_flag = 0; if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/'))) fatal("sshd re-exec requires execution with an absolute path"); if (rexeced_flag) closefrom(REEXEC_MIN_FREE_FD); else closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); #ifdef WITH_OPENSSL OpenSSL_add_all_algorithms(); #endif /* If requested, redirect the logs to the specified logfile. */ if (logfile != NULL) log_redirect_stderr_to(logfile); /* * Force logging to stderr until we have loaded the private host * key (unless started from inetd) */ log_init(__progname, options.log_level == SYSLOG_LEVEL_NOT_SET ? SYSLOG_LEVEL_INFO : options.log_level, options.log_facility == SYSLOG_FACILITY_NOT_SET ? SYSLOG_FACILITY_AUTH : options.log_facility, log_stderr || !inetd_flag); /* * Unset KRB5CCNAME, otherwise the user's session may inherit it from * root's environment */ if (getenv("KRB5CCNAME") != NULL) (void) unsetenv("KRB5CCNAME"); #ifdef _UNICOS /* Cray can define user privs drop all privs now! * Not needed on PRIV_SU systems! */ drop_cray_privs(); #endif sensitive_data.have_ssh2_key = 0; /* * If we're doing an extended config test, make sure we have all of * the parameters we need. If we're not doing an extended test, * do not silently ignore connection test params. */ if (test_flag >= 2 && server_match_spec_complete(connection_info) == 0) fatal("user, host and addr are all required when testing " "Match configs"); if (test_flag < 2 && server_match_spec_complete(connection_info) >= 0) fatal("Config test connection parameter (-C) provided without " "test mode (-T)"); /* Fetch our configuration */ buffer_init(&cfg); if (rexeced_flag) recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); else if (strcasecmp(config_file_name, "none") != 0) load_server_config(config_file_name, &cfg); parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name, &cfg, NULL); seed_rng(); /* Fill in default values for those options not explicitly set. */ fill_default_server_options(&options); /* challenge-response is implemented via keyboard interactive */ if (options.challenge_response_authentication) options.kbd_interactive_authentication = 1; /* Check that options are sensible */ if (options.authorized_keys_command_user == NULL && (options.authorized_keys_command != NULL && strcasecmp(options.authorized_keys_command, "none") != 0)) fatal("AuthorizedKeysCommand set without " "AuthorizedKeysCommandUser"); if (options.authorized_principals_command_user == NULL && (options.authorized_principals_command != NULL && strcasecmp(options.authorized_principals_command, "none") != 0)) fatal("AuthorizedPrincipalsCommand set without " "AuthorizedPrincipalsCommandUser"); /* * Check whether there is any path through configured auth methods. * Unfortunately it is not possible to verify this generally before * daemonisation in the presence of Match block, but this catches * and warns for trivial misconfigurations that could break login. */ if (options.num_auth_methods != 0) { for (n = 0; n < options.num_auth_methods; n++) { if (auth2_methods_valid(options.auth_methods[n], 1) == 0) break; } if (n >= options.num_auth_methods) fatal("AuthenticationMethods cannot be satisfied by " "enabled authentication methods"); } /* set default channel AF */ channel_set_af(options.address_family); /* Check that there are no remaining arguments. */ if (optind < ac) { fprintf(stderr, "Extra argument %s.\n", av[optind]); exit(1); } debug("sshd version %s, %s", SSH_VERSION, #ifdef WITH_OPENSSL SSLeay_version(SSLEAY_VERSION) #else "without OpenSSL" #endif ); /* Store privilege separation user for later use if required. */ if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) { if (use_privsep || options.kerberos_authentication) fatal("Privilege separation user %s does not exist", SSH_PRIVSEP_USER); } else { explicit_bzero(privsep_pw->pw_passwd, strlen(privsep_pw->pw_passwd)); privsep_pw = pwcopy(privsep_pw); free(privsep_pw->pw_passwd); privsep_pw->pw_passwd = xstrdup("*"); } endpwent(); /* load host keys */ sensitive_data.host_keys = xcalloc(options.num_host_key_files, sizeof(Key *)); sensitive_data.host_pubkeys = xcalloc(options.num_host_key_files, sizeof(Key *)); if (options.host_key_agent) { if (strcmp(options.host_key_agent, SSH_AUTHSOCKET_ENV_NAME)) setenv(SSH_AUTHSOCKET_ENV_NAME, options.host_key_agent, 1); if ((r = ssh_get_authentication_socket(NULL)) == 0) have_agent = 1; else error("Could not connect to agent \"%s\": %s", options.host_key_agent, ssh_err(r)); } for (i = 0; i < options.num_host_key_files; i++) { if (options.host_key_files[i] == NULL) continue; key = key_load_private(options.host_key_files[i], "", NULL); pubkey = key_load_public(options.host_key_files[i], NULL); if (pubkey == NULL && key != NULL) pubkey = key_demote(key); sensitive_data.host_keys[i] = key; sensitive_data.host_pubkeys[i] = pubkey; if (key == NULL && pubkey != NULL && have_agent) { debug("will rely on agent for hostkey %s", options.host_key_files[i]); keytype = pubkey->type; } else if (key != NULL) { keytype = key->type; } else { error("Could not load host key: %s", options.host_key_files[i]); sensitive_data.host_keys[i] = NULL; sensitive_data.host_pubkeys[i] = NULL; continue; } switch (keytype) { case KEY_RSA: case KEY_DSA: case KEY_ECDSA: case KEY_ED25519: if (have_agent || key != NULL) sensitive_data.have_ssh2_key = 1; break; } if ((fp = sshkey_fingerprint(pubkey, options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) fatal("sshkey_fingerprint failed"); debug("%s host key #%d: %s %s", key ? "private" : "agent", i, sshkey_ssh_name(pubkey), fp); free(fp); } if (!sensitive_data.have_ssh2_key) { logit("sshd: no hostkeys available -- exiting."); exit(1); } /* * Load certificates. They are stored in an array at identical * indices to the public keys that they relate to. */ sensitive_data.host_certificates = xcalloc(options.num_host_key_files, sizeof(Key *)); for (i = 0; i < options.num_host_key_files; i++) sensitive_data.host_certificates[i] = NULL; for (i = 0; i < options.num_host_cert_files; i++) { if (options.host_cert_files[i] == NULL) continue; key = key_load_public(options.host_cert_files[i], NULL); if (key == NULL) { error("Could not load host certificate: %s", options.host_cert_files[i]); continue; } if (!key_is_cert(key)) { error("Certificate file is not a certificate: %s", options.host_cert_files[i]); key_free(key); continue; } /* Find matching private key */ for (j = 0; j < options.num_host_key_files; j++) { if (key_equal_public(key, sensitive_data.host_keys[j])) { sensitive_data.host_certificates[j] = key; break; } } if (j >= options.num_host_key_files) { error("No matching private key for certificate: %s", options.host_cert_files[i]); key_free(key); continue; } sensitive_data.host_certificates[j] = key; debug("host certificate: #%d type %d %s", j, key->type, key_type(key)); } if (use_privsep) { struct stat st; if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || (S_ISDIR(st.st_mode) == 0)) fatal("Missing privilege separation directory: %s", _PATH_PRIVSEP_CHROOT_DIR); #ifdef HAVE_CYGWIN if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && (st.st_uid != getuid () || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) #else if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) #endif fatal("%s must be owned by root and not group or " "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); } if (test_flag > 1) { if (server_match_spec_complete(connection_info) == 1) parse_server_match_config(&options, connection_info); dump_config(&options); } /* Configuration looks good, so exit if in test mode. */ if (test_flag) exit(0); /* * Clear out any supplemental groups we may have inherited. This * prevents inadvertent creation of files with bad modes (in the * portable version at least, it's certainly possible for PAM * to create a file, and we can't control the code in every * module which might be used). */ if (setgroups(0, NULL) < 0) debug("setgroups() failed: %.200s", strerror(errno)); if (rexec_flag) { rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *)); for (i = 0; i < rexec_argc; i++) { debug("rexec_argv[%d]='%s'", i, saved_argv[i]); rexec_argv[i] = saved_argv[i]; } rexec_argv[rexec_argc] = "-R"; rexec_argv[rexec_argc + 1] = NULL; } /* Ensure that umask disallows at least group and world write */ new_umask = umask(0077) | 0022; (void) umask(new_umask); /* Initialize the log (it is reinitialized below in case we forked). */ if (debug_flag && (!inetd_flag || rexeced_flag)) log_stderr = 1; log_init(__progname, options.log_level, options.log_facility, log_stderr); /* * If not in debugging mode, not started from inetd and not already * daemonized (eg re-exec via SIGHUP), disconnect from the controlling * terminal, and fork. The original process exits. */ already_daemon = daemonized(); if (!(debug_flag || inetd_flag || no_daemon_flag || already_daemon)) { if (daemon(0, 0) < 0) fatal("daemon() failed: %.200s", strerror(errno)); disconnect_controlling_tty(); } /* Reinitialize the log (because of the fork above). */ log_init(__progname, options.log_level, options.log_facility, log_stderr); /* Avoid killing the process in high-pressure swapping environments. */ if (!inetd_flag && madvise(NULL, 0, MADV_PROTECT) != 0) debug("madvise(): %.200s", strerror(errno)); /* Chdir to the root directory so that the current disk can be unmounted if desired. */ if (chdir("/") == -1) error("chdir(\"/\"): %s", strerror(errno)); /* ignore SIGPIPE */ signal(SIGPIPE, SIG_IGN); /* Get a connection, either from inetd or a listening TCP socket */ if (inetd_flag) { server_accept_inetd(&sock_in, &sock_out); } else { platform_pre_listen(); server_listen(); signal(SIGHUP, sighup_handler); signal(SIGCHLD, main_sigchld_handler); signal(SIGTERM, sigterm_handler); signal(SIGQUIT, sigterm_handler); /* * Write out the pid file after the sigterm handler * is setup and the listen sockets are bound */ if (options.pid_file != NULL && !debug_flag) { FILE *f = fopen(options.pid_file, "w"); if (f == NULL) { error("Couldn't create pid file \"%s\": %s", options.pid_file, strerror(errno)); } else { fprintf(f, "%ld\n", (long) getpid()); fclose(f); } } /* Accept a connection and return in a forked child */ server_accept_loop(&sock_in, &sock_out, &newsock, config_s); } /* This is the child processing a new connection. */ setproctitle("%s", "[accepted]"); /* * Create a new session and process group since the 4.4BSD * setlogin() affects the entire process group. We don't * want the child to be able to affect the parent. */ #if !defined(SSHD_ACQUIRES_CTTY) /* * If setsid is called, on some platforms sshd will later acquire a * controlling terminal which will result in "could not set * controlling tty" errors. */ if (!debug_flag && !inetd_flag && setsid() < 0) error("setsid: %.100s", strerror(errno)); #endif if (rexec_flag) { int fd; debug("rexec start in %d out %d newsock %d pipe %d sock %d", sock_in, sock_out, newsock, startup_pipe, config_s[0]); dup2(newsock, STDIN_FILENO); dup2(STDIN_FILENO, STDOUT_FILENO); if (startup_pipe == -1) close(REEXEC_STARTUP_PIPE_FD); else if (startup_pipe != REEXEC_STARTUP_PIPE_FD) { dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); close(startup_pipe); startup_pipe = REEXEC_STARTUP_PIPE_FD; } dup2(config_s[1], REEXEC_CONFIG_PASS_FD); close(config_s[1]); execv(rexec_argv[0], rexec_argv); /* Reexec has failed, fall back and continue */ error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); log_init(__progname, options.log_level, options.log_facility, log_stderr); /* Clean up fds */ close(REEXEC_CONFIG_PASS_FD); newsock = sock_out = sock_in = dup(STDIN_FILENO); if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { dup2(fd, STDIN_FILENO); dup2(fd, STDOUT_FILENO); if (fd > STDERR_FILENO) close(fd); } debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", sock_in, sock_out, newsock, startup_pipe, config_s[0]); } /* Executed child processes don't need these. */ fcntl(sock_out, F_SETFD, FD_CLOEXEC); fcntl(sock_in, F_SETFD, FD_CLOEXEC); /* * Disable the key regeneration alarm. We will not regenerate the * key since we are no longer in a position to give it to anyone. We * will not restart on SIGHUP since it no longer makes sense. */ alarm(0); signal(SIGALRM, SIG_DFL); signal(SIGHUP, SIG_DFL); signal(SIGTERM, SIG_DFL); signal(SIGQUIT, SIG_DFL); signal(SIGCHLD, SIG_DFL); signal(SIGINT, SIG_DFL); #ifdef __FreeBSD__ /* * Initialize the resolver. This may not happen automatically * before privsep chroot(). */ if ((_res.options & RES_INIT) == 0) { debug("res_init()"); res_init(); } #ifdef GSSAPI /* * Force GSS-API to parse its configuration and load any * mechanism plugins. */ { gss_OID_set mechs; OM_uint32 minor_status; gss_indicate_mechs(&minor_status, &mechs); gss_release_oid_set(&minor_status, &mechs); } #endif #endif /* * Register our connection. This turns encryption off because we do * not have a key. */ packet_set_connection(sock_in, sock_out); packet_set_server(); ssh = active_state; /* XXX */ check_ip_options(ssh); /* Set SO_KEEPALIVE if requested. */ if (options.tcp_keep_alive && packet_connection_is_on_socket() && setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); if ((remote_port = ssh_remote_port(ssh)) < 0) { debug("ssh_remote_port failed"); cleanup_exit(255); } /* * The rest of the code depends on the fact that * ssh_remote_ipaddr() caches the remote ip, even if * the socket goes away. */ remote_ip = ssh_remote_ipaddr(ssh); #ifdef SSH_AUDIT_EVENTS audit_connection_from(remote_ip, remote_port); #endif #ifdef LIBWRAP allow_severity = options.log_facility|LOG_INFO; deny_severity = options.log_facility|LOG_WARNING; /* Check whether logins are denied from this host. */ if (packet_connection_is_on_socket()) { struct request_info req; request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); fromhost(&req); if (!hosts_access(&req)) { debug("Connection refused by tcp wrapper"); refuse(&req); /* NOTREACHED */ fatal("libwrap refuse returns"); } } #endif /* LIBWRAP */ /* Log the connection. */ laddr = get_local_ipaddr(sock_in); verbose("Connection from %s port %d on %s port %d", remote_ip, remote_port, laddr, ssh_local_port(ssh)); free(laddr); /* * We don't want to listen forever unless the other side * successfully authenticates itself. So we set up an alarm which is * cleared after successful authentication. A limit of zero * indicates no limit. Note that we don't set the alarm in debugging * mode; it is just annoying to have the server exit just when you * are about to discover the bug. */ signal(SIGALRM, grace_alarm_handler); if (!debug_flag) alarm(options.login_grace_time); sshd_exchange_identification(ssh, sock_in, sock_out); packet_set_nonblocking(); /* allocate authentication context */ authctxt = xcalloc(1, sizeof(*authctxt)); authctxt->loginmsg = &loginmsg; /* XXX global for cleanup, access from other modules */ the_authctxt = authctxt; /* prepare buffer to collect messages to display to user after login */ buffer_init(&loginmsg); auth_debug_reset(); BLACKLIST_INIT(); if (use_privsep) { if (privsep_preauth(authctxt) == 1) goto authenticated; } else if (have_agent) { if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) { error("Unable to get agent socket: %s", ssh_err(r)); have_agent = 0; } } /* perform the key exchange */ /* authenticate user and start session */ do_ssh2_kex(); do_authentication2(authctxt); /* * If we use privilege separation, the unprivileged child transfers * the current keystate and exits */ if (use_privsep) { mm_send_keystate(pmonitor); exit(0); } authenticated: /* * Cancel the alarm we set to limit the time taken for * authentication. */ alarm(0); signal(SIGALRM, SIG_DFL); authctxt->authenticated = 1; if (startup_pipe != -1) { close(startup_pipe); startup_pipe = -1; } #ifdef SSH_AUDIT_EVENTS audit_event(SSH_AUTH_SUCCESS); #endif #ifdef GSSAPI if (options.gss_authentication) { temporarily_use_uid(authctxt->pw); ssh_gssapi_storecreds(); restore_uid(); } #endif #ifdef USE_PAM if (options.use_pam) { do_pam_setcred(1); do_pam_session(); } #endif /* * In privilege separation, we fork another child and prepare * file descriptor passing. */ if (use_privsep) { privsep_postauth(authctxt); /* the monitor process [priv] will not return */ } packet_set_timeout(options.client_alive_interval, options.client_alive_count_max); /* Try to send all our hostkeys to the client */ notify_hostkeys(active_state); /* Start session. */ do_authenticated(authctxt); /* The connection has been terminated. */ packet_get_bytes(&ibytes, &obytes); verbose("Transferred: sent %llu, received %llu bytes", (unsigned long long)obytes, (unsigned long long)ibytes); verbose("Closing connection to %.500s port %d", remote_ip, remote_port); #ifdef USE_PAM if (options.use_pam) finish_pam(); #endif /* USE_PAM */ #ifdef SSH_AUDIT_EVENTS PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); #endif packet_close(); if (use_privsep) mm_terminate(); exit(0); } int sshd_hostkey_sign(Key *privkey, Key *pubkey, u_char **signature, size_t *slen, const u_char *data, size_t dlen, const char *alg, u_int flag) { int r; u_int xxx_slen, xxx_dlen = dlen; if (privkey) { if (PRIVSEP(key_sign(privkey, signature, &xxx_slen, data, xxx_dlen, alg) < 0)) fatal("%s: key_sign failed", __func__); if (slen) *slen = xxx_slen; } else if (use_privsep) { if (mm_key_sign(pubkey, signature, &xxx_slen, data, xxx_dlen, alg) < 0) fatal("%s: pubkey_sign failed", __func__); if (slen) *slen = xxx_slen; } else { if ((r = ssh_agent_sign(auth_sock, pubkey, signature, slen, data, dlen, alg, datafellows)) != 0) fatal("%s: ssh_agent_sign failed: %s", __func__, ssh_err(r)); } return 0; } /* SSH2 key exchange */ static void do_ssh2_kex(void) { char *myproposal[PROPOSAL_MAX] = { KEX_SERVER }; struct kex *kex; int r; myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal( options.kex_algorithms); myproposal[PROPOSAL_ENC_ALGS_CTOS] = compat_cipher_proposal( options.ciphers); myproposal[PROPOSAL_ENC_ALGS_STOC] = compat_cipher_proposal( options.ciphers); myproposal[PROPOSAL_MAC_ALGS_CTOS] = myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; if (options.compression == COMP_NONE) { myproposal[PROPOSAL_COMP_ALGS_CTOS] = myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; } if (options.rekey_limit || options.rekey_interval) packet_set_rekey_limits(options.rekey_limit, (time_t)options.rekey_interval); myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal( list_hostkey_types()); /* start key exchange */ if ((r = kex_setup(active_state, myproposal)) != 0) fatal("kex_setup: %s", ssh_err(r)); kex = active_state->kex; #ifdef WITH_OPENSSL kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; kex->kex[KEX_DH_GRP14_SHA256] = kexdh_server; kex->kex[KEX_DH_GRP16_SHA512] = kexdh_server; kex->kex[KEX_DH_GRP18_SHA512] = kexdh_server; kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; # ifdef OPENSSL_HAS_ECC kex->kex[KEX_ECDH_SHA2] = kexecdh_server; # endif #endif kex->kex[KEX_C25519_SHA256] = kexc25519_server; kex->server = 1; kex->client_version_string=client_version_string; kex->server_version_string=server_version_string; kex->load_host_public_key=&get_hostkey_public_by_type; kex->load_host_private_key=&get_hostkey_private_by_type; kex->host_key_index=&get_hostkey_index; kex->sign = sshd_hostkey_sign; dispatch_run(DISPATCH_BLOCK, &kex->done, active_state); session_id2 = kex->session_id; session_id2_len = kex->session_id_len; #ifdef DEBUG_KEXDH /* send 1st encrypted/maced/compressed message */ packet_start(SSH2_MSG_IGNORE); packet_put_cstring("markus"); packet_send(); packet_write_wait(); #endif debug("KEX done"); } /* server specific fatal cleanup */ void cleanup_exit(int i) { if (the_authctxt) { do_cleanup(the_authctxt); if (use_privsep && privsep_is_preauth && pmonitor != NULL && pmonitor->m_pid > 1) { debug("Killing privsep child %d", pmonitor->m_pid); if (kill(pmonitor->m_pid, SIGKILL) != 0 && errno != ESRCH) error("%s: kill(%d): %s", __func__, pmonitor->m_pid, strerror(errno)); } } #ifdef SSH_AUDIT_EVENTS /* done after do_cleanup so it can cancel the PAM auth 'thread' */ if (!use_privsep || mm_is_monitor()) audit_event(SSH_CONNECTION_ABANDON); #endif _exit(i); }