diff --git a/crypto/openssh/misc.c b/crypto/openssh/misc.c index 662d6bf48716..bdc06fdb3332 100644 --- a/crypto/openssh/misc.c +++ b/crypto/openssh/misc.c @@ -1,2040 +1,2039 @@ /* $OpenBSD: misc.c,v 1.133 2018/10/05 14:26:09 naddy Exp $ */ /* * Copyright (c) 2000 Markus Friedl. All rights reserved. * Copyright (c) 2005,2006 Damien Miller. 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" #include #include #include #include -#include #include #include #include #include #ifdef HAVE_LIBGEN_H # include #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef HAVE_PATHS_H # include #include #endif #ifdef SSH_TUN_OPENBSD #include #endif #include "xmalloc.h" #include "misc.h" #include "log.h" #include "ssh.h" #include "sshbuf.h" #include "ssherr.h" #include "platform.h" /* remove newline at end of string */ char * chop(char *s) { char *t = s; while (*t) { if (*t == '\n' || *t == '\r') { *t = '\0'; return s; } t++; } return s; } /* set/unset filedescriptor to non-blocking */ int set_nonblock(int fd) { int val; val = fcntl(fd, F_GETFL); if (val < 0) { error("fcntl(%d, F_GETFL): %s", fd, strerror(errno)); return (-1); } if (val & O_NONBLOCK) { debug3("fd %d is O_NONBLOCK", fd); return (0); } debug2("fd %d setting O_NONBLOCK", fd); val |= O_NONBLOCK; if (fcntl(fd, F_SETFL, val) == -1) { debug("fcntl(%d, F_SETFL, O_NONBLOCK): %s", fd, strerror(errno)); return (-1); } return (0); } int unset_nonblock(int fd) { int val; val = fcntl(fd, F_GETFL); if (val < 0) { error("fcntl(%d, F_GETFL): %s", fd, strerror(errno)); return (-1); } if (!(val & O_NONBLOCK)) { debug3("fd %d is not O_NONBLOCK", fd); return (0); } debug("fd %d clearing O_NONBLOCK", fd); val &= ~O_NONBLOCK; if (fcntl(fd, F_SETFL, val) == -1) { debug("fcntl(%d, F_SETFL, ~O_NONBLOCK): %s", fd, strerror(errno)); return (-1); } return (0); } const char * ssh_gai_strerror(int gaierr) { if (gaierr == EAI_SYSTEM && errno != 0) return strerror(errno); return gai_strerror(gaierr); } /* disable nagle on socket */ void set_nodelay(int fd) { int opt; socklen_t optlen; optlen = sizeof opt; if (getsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, &optlen) == -1) { debug("getsockopt TCP_NODELAY: %.100s", strerror(errno)); return; } if (opt == 1) { debug2("fd %d is TCP_NODELAY", fd); return; } opt = 1; debug2("fd %d setting TCP_NODELAY", fd); if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof opt) == -1) error("setsockopt TCP_NODELAY: %.100s", strerror(errno)); } /* Allow local port reuse in TIME_WAIT */ int set_reuseaddr(int fd) { int on = 1; if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1) { error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno)); return -1; } return 0; } /* Get/set routing domain */ char * get_rdomain(int fd) { #if defined(HAVE_SYS_GET_RDOMAIN) return sys_get_rdomain(fd); #elif defined(__OpenBSD__) int rtable; char *ret; socklen_t len = sizeof(rtable); if (getsockopt(fd, SOL_SOCKET, SO_RTABLE, &rtable, &len) == -1) { error("Failed to get routing domain for fd %d: %s", fd, strerror(errno)); return NULL; } xasprintf(&ret, "%d", rtable); return ret; #else /* defined(__OpenBSD__) */ return NULL; #endif } int set_rdomain(int fd, const char *name) { #if defined(HAVE_SYS_SET_RDOMAIN) return sys_set_rdomain(fd, name); #elif defined(__OpenBSD__) int rtable; const char *errstr; if (name == NULL) return 0; /* default table */ rtable = (int)strtonum(name, 0, 255, &errstr); if (errstr != NULL) { /* Shouldn't happen */ error("Invalid routing domain \"%s\": %s", name, errstr); return -1; } if (setsockopt(fd, SOL_SOCKET, SO_RTABLE, &rtable, sizeof(rtable)) == -1) { error("Failed to set routing domain %d on fd %d: %s", rtable, fd, strerror(errno)); return -1; } return 0; #else /* defined(__OpenBSD__) */ error("Setting routing domain is not supported on this platform"); return -1; #endif } /* Characters considered whitespace in strsep calls. */ #define WHITESPACE " \t\r\n" #define QUOTE "\"" /* return next token in configuration line */ static char * strdelim_internal(char **s, int split_equals) { char *old; int wspace = 0; if (*s == NULL) return NULL; old = *s; *s = strpbrk(*s, split_equals ? WHITESPACE QUOTE "=" : WHITESPACE QUOTE); if (*s == NULL) return (old); if (*s[0] == '\"') { memmove(*s, *s + 1, strlen(*s)); /* move nul too */ /* Find matching quote */ if ((*s = strpbrk(*s, QUOTE)) == NULL) { return (NULL); /* no matching quote */ } else { *s[0] = '\0'; *s += strspn(*s + 1, WHITESPACE) + 1; return (old); } } /* Allow only one '=' to be skipped */ if (split_equals && *s[0] == '=') wspace = 1; *s[0] = '\0'; /* Skip any extra whitespace after first token */ *s += strspn(*s + 1, WHITESPACE) + 1; if (split_equals && *s[0] == '=' && !wspace) *s += strspn(*s + 1, WHITESPACE) + 1; return (old); } /* * Return next token in configuration line; splts on whitespace or a * single '=' character. */ char * strdelim(char **s) { return strdelim_internal(s, 1); } /* * Return next token in configuration line; splts on whitespace only. */ char * strdelimw(char **s) { return strdelim_internal(s, 0); } struct passwd * pwcopy(struct passwd *pw) { struct passwd *copy = xcalloc(1, sizeof(*copy)); copy->pw_name = xstrdup(pw->pw_name); copy->pw_passwd = xstrdup(pw->pw_passwd); #ifdef HAVE_STRUCT_PASSWD_PW_GECOS copy->pw_gecos = xstrdup(pw->pw_gecos); #endif copy->pw_uid = pw->pw_uid; copy->pw_gid = pw->pw_gid; #ifdef HAVE_STRUCT_PASSWD_PW_EXPIRE copy->pw_expire = pw->pw_expire; #endif #ifdef HAVE_STRUCT_PASSWD_PW_CHANGE copy->pw_change = pw->pw_change; #endif #ifdef HAVE_STRUCT_PASSWD_PW_CLASS copy->pw_class = xstrdup(pw->pw_class); #endif copy->pw_dir = xstrdup(pw->pw_dir); copy->pw_shell = xstrdup(pw->pw_shell); return copy; } /* * Convert ASCII string to TCP/IP port number. * Port must be >=0 and <=65535. * Return -1 if invalid. */ int a2port(const char *s) { struct servent *se; long long port; const char *errstr; port = strtonum(s, 0, 65535, &errstr); if (errstr == NULL) return (int)port; if ((se = getservbyname(s, "tcp")) != NULL) return ntohs(se->s_port); return -1; } int a2tun(const char *s, int *remote) { const char *errstr = NULL; char *sp, *ep; int tun; if (remote != NULL) { *remote = SSH_TUNID_ANY; sp = xstrdup(s); if ((ep = strchr(sp, ':')) == NULL) { free(sp); return (a2tun(s, NULL)); } ep[0] = '\0'; ep++; *remote = a2tun(ep, NULL); tun = a2tun(sp, NULL); free(sp); return (*remote == SSH_TUNID_ERR ? *remote : tun); } if (strcasecmp(s, "any") == 0) return (SSH_TUNID_ANY); tun = strtonum(s, 0, SSH_TUNID_MAX, &errstr); if (errstr != NULL) return (SSH_TUNID_ERR); return (tun); } #define SECONDS 1 #define MINUTES (SECONDS * 60) #define HOURS (MINUTES * 60) #define DAYS (HOURS * 24) #define WEEKS (DAYS * 7) /* * Convert a time string into seconds; format is * a sequence of: * time[qualifier] * * Valid time qualifiers are: * seconds * s|S seconds * m|M minutes * h|H hours * d|D days * w|W weeks * * Examples: * 90m 90 minutes * 1h30m 90 minutes * 2d 2 days * 1w 1 week * * Return -1 if time string is invalid. */ long convtime(const char *s) { long total, secs, multiplier = 1; const char *p; char *endp; errno = 0; total = 0; p = s; if (p == NULL || *p == '\0') return -1; while (*p) { secs = strtol(p, &endp, 10); if (p == endp || (errno == ERANGE && (secs == LONG_MIN || secs == LONG_MAX)) || secs < 0) return -1; switch (*endp++) { case '\0': endp--; break; case 's': case 'S': break; case 'm': case 'M': multiplier = MINUTES; break; case 'h': case 'H': multiplier = HOURS; break; case 'd': case 'D': multiplier = DAYS; break; case 'w': case 'W': multiplier = WEEKS; break; default: return -1; } if (secs >= LONG_MAX / multiplier) return -1; secs *= multiplier; if (total >= LONG_MAX - secs) return -1; total += secs; if (total < 0) return -1; p = endp; } return total; } /* * Returns a standardized host+port identifier string. * Caller must free returned string. */ char * put_host_port(const char *host, u_short port) { char *hoststr; if (port == 0 || port == SSH_DEFAULT_PORT) return(xstrdup(host)); if (asprintf(&hoststr, "[%s]:%d", host, (int)port) < 0) fatal("put_host_port: asprintf: %s", strerror(errno)); debug3("put_host_port: %s", hoststr); return hoststr; } /* * Search for next delimiter between hostnames/addresses and ports. * Argument may be modified (for termination). * Returns *cp if parsing succeeds. * *cp is set to the start of the next field, if one was found. * The delimiter char, if present, is stored in delim. * If this is the last field, *cp is set to NULL. */ static char * hpdelim2(char **cp, char *delim) { char *s, *old; if (cp == NULL || *cp == NULL) return NULL; old = s = *cp; if (*s == '[') { if ((s = strchr(s, ']')) == NULL) return NULL; else s++; } else if ((s = strpbrk(s, ":/")) == NULL) s = *cp + strlen(*cp); /* skip to end (see first case below) */ switch (*s) { case '\0': *cp = NULL; /* no more fields*/ break; case ':': case '/': if (delim != NULL) *delim = *s; *s = '\0'; /* terminate */ *cp = s + 1; break; default: return NULL; } return old; } char * hpdelim(char **cp) { return hpdelim2(cp, NULL); } char * cleanhostname(char *host) { if (*host == '[' && host[strlen(host) - 1] == ']') { host[strlen(host) - 1] = '\0'; return (host + 1); } else return host; } char * colon(char *cp) { int flag = 0; if (*cp == ':') /* Leading colon is part of file name. */ return NULL; if (*cp == '[') flag = 1; for (; *cp; ++cp) { if (*cp == '@' && *(cp+1) == '[') flag = 1; if (*cp == ']' && *(cp+1) == ':' && flag) return (cp+1); if (*cp == ':' && !flag) return (cp); if (*cp == '/') return NULL; } return NULL; } /* * Parse a [user@]host:[path] string. * Caller must free returned user, host and path. * Any of the pointer return arguments may be NULL (useful for syntax checking). * If user was not specified then *userp will be set to NULL. * If host was not specified then *hostp will be set to NULL. * If path was not specified then *pathp will be set to ".". * Returns 0 on success, -1 on failure. */ int parse_user_host_path(const char *s, char **userp, char **hostp, char **pathp) { char *user = NULL, *host = NULL, *path = NULL; char *sdup, *tmp; int ret = -1; if (userp != NULL) *userp = NULL; if (hostp != NULL) *hostp = NULL; if (pathp != NULL) *pathp = NULL; sdup = xstrdup(s); /* Check for remote syntax: [user@]host:[path] */ if ((tmp = colon(sdup)) == NULL) goto out; /* Extract optional path */ *tmp++ = '\0'; if (*tmp == '\0') tmp = "."; path = xstrdup(tmp); /* Extract optional user and mandatory host */ tmp = strrchr(sdup, '@'); if (tmp != NULL) { *tmp++ = '\0'; host = xstrdup(cleanhostname(tmp)); if (*sdup != '\0') user = xstrdup(sdup); } else { host = xstrdup(cleanhostname(sdup)); user = NULL; } /* Success */ if (userp != NULL) { *userp = user; user = NULL; } if (hostp != NULL) { *hostp = host; host = NULL; } if (pathp != NULL) { *pathp = path; path = NULL; } ret = 0; out: free(sdup); free(user); free(host); free(path); return ret; } /* * Parse a [user@]host[:port] string. * Caller must free returned user and host. * Any of the pointer return arguments may be NULL (useful for syntax checking). * If user was not specified then *userp will be set to NULL. * If port was not specified then *portp will be -1. * Returns 0 on success, -1 on failure. */ int parse_user_host_port(const char *s, char **userp, char **hostp, int *portp) { char *sdup, *cp, *tmp; char *user = NULL, *host = NULL; int port = -1, ret = -1; if (userp != NULL) *userp = NULL; if (hostp != NULL) *hostp = NULL; if (portp != NULL) *portp = -1; if ((sdup = tmp = strdup(s)) == NULL) return -1; /* Extract optional username */ if ((cp = strrchr(tmp, '@')) != NULL) { *cp = '\0'; if (*tmp == '\0') goto out; if ((user = strdup(tmp)) == NULL) goto out; tmp = cp + 1; } /* Extract mandatory hostname */ if ((cp = hpdelim(&tmp)) == NULL || *cp == '\0') goto out; host = xstrdup(cleanhostname(cp)); /* Convert and verify optional port */ if (tmp != NULL && *tmp != '\0') { if ((port = a2port(tmp)) <= 0) goto out; } /* Success */ if (userp != NULL) { *userp = user; user = NULL; } if (hostp != NULL) { *hostp = host; host = NULL; } if (portp != NULL) *portp = port; ret = 0; out: free(sdup); free(user); free(host); return ret; } /* * Converts a two-byte hex string to decimal. * Returns the decimal value or -1 for invalid input. */ static int hexchar(const char *s) { unsigned char result[2]; int i; for (i = 0; i < 2; i++) { if (s[i] >= '0' && s[i] <= '9') result[i] = (unsigned char)(s[i] - '0'); else if (s[i] >= 'a' && s[i] <= 'f') result[i] = (unsigned char)(s[i] - 'a') + 10; else if (s[i] >= 'A' && s[i] <= 'F') result[i] = (unsigned char)(s[i] - 'A') + 10; else return -1; } return (result[0] << 4) | result[1]; } /* * Decode an url-encoded string. * Returns a newly allocated string on success or NULL on failure. */ static char * urldecode(const char *src) { char *ret, *dst; int ch; ret = xmalloc(strlen(src) + 1); for (dst = ret; *src != '\0'; src++) { switch (*src) { case '+': *dst++ = ' '; break; case '%': if (!isxdigit((unsigned char)src[1]) || !isxdigit((unsigned char)src[2]) || (ch = hexchar(src + 1)) == -1) { free(ret); return NULL; } *dst++ = ch; src += 2; break; default: *dst++ = *src; break; } } *dst = '\0'; return ret; } /* * Parse an (scp|ssh|sftp)://[user@]host[:port][/path] URI. * See https://tools.ietf.org/html/draft-ietf-secsh-scp-sftp-ssh-uri-04 * Either user or path may be url-encoded (but not host or port). * Caller must free returned user, host and path. * Any of the pointer return arguments may be NULL (useful for syntax checking) * but the scheme must always be specified. * If user was not specified then *userp will be set to NULL. * If port was not specified then *portp will be -1. * If path was not specified then *pathp will be set to NULL. * Returns 0 on success, 1 if non-uri/wrong scheme, -1 on error/invalid uri. */ int parse_uri(const char *scheme, const char *uri, char **userp, char **hostp, int *portp, char **pathp) { char *uridup, *cp, *tmp, ch; char *user = NULL, *host = NULL, *path = NULL; int port = -1, ret = -1; size_t len; len = strlen(scheme); if (strncmp(uri, scheme, len) != 0 || strncmp(uri + len, "://", 3) != 0) return 1; uri += len + 3; if (userp != NULL) *userp = NULL; if (hostp != NULL) *hostp = NULL; if (portp != NULL) *portp = -1; if (pathp != NULL) *pathp = NULL; uridup = tmp = xstrdup(uri); /* Extract optional ssh-info (username + connection params) */ if ((cp = strchr(tmp, '@')) != NULL) { char *delim; *cp = '\0'; /* Extract username and connection params */ if ((delim = strchr(tmp, ';')) != NULL) { /* Just ignore connection params for now */ *delim = '\0'; } if (*tmp == '\0') { /* Empty username */ goto out; } if ((user = urldecode(tmp)) == NULL) goto out; tmp = cp + 1; } /* Extract mandatory hostname */ if ((cp = hpdelim2(&tmp, &ch)) == NULL || *cp == '\0') goto out; host = xstrdup(cleanhostname(cp)); if (!valid_domain(host, 0, NULL)) goto out; if (tmp != NULL && *tmp != '\0') { if (ch == ':') { /* Convert and verify port. */ if ((cp = strchr(tmp, '/')) != NULL) *cp = '\0'; if ((port = a2port(tmp)) <= 0) goto out; tmp = cp ? cp + 1 : NULL; } if (tmp != NULL && *tmp != '\0') { /* Extract optional path */ if ((path = urldecode(tmp)) == NULL) goto out; } } /* Success */ if (userp != NULL) { *userp = user; user = NULL; } if (hostp != NULL) { *hostp = host; host = NULL; } if (portp != NULL) *portp = port; if (pathp != NULL) { *pathp = path; path = NULL; } ret = 0; out: free(uridup); free(user); free(host); free(path); return ret; } /* function to assist building execv() arguments */ void addargs(arglist *args, char *fmt, ...) { va_list ap; char *cp; u_int nalloc; int r; va_start(ap, fmt); r = vasprintf(&cp, fmt, ap); va_end(ap); if (r == -1) fatal("addargs: argument too long"); nalloc = args->nalloc; if (args->list == NULL) { nalloc = 32; args->num = 0; } else if (args->num+2 >= nalloc) nalloc *= 2; args->list = xrecallocarray(args->list, args->nalloc, nalloc, sizeof(char *)); args->nalloc = nalloc; args->list[args->num++] = cp; args->list[args->num] = NULL; } void replacearg(arglist *args, u_int which, char *fmt, ...) { va_list ap; char *cp; int r; va_start(ap, fmt); r = vasprintf(&cp, fmt, ap); va_end(ap); if (r == -1) fatal("replacearg: argument too long"); if (which >= args->num) fatal("replacearg: tried to replace invalid arg %d >= %d", which, args->num); free(args->list[which]); args->list[which] = cp; } void freeargs(arglist *args) { u_int i; if (args->list != NULL) { for (i = 0; i < args->num; i++) free(args->list[i]); free(args->list); args->nalloc = args->num = 0; args->list = NULL; } } /* * Expands tildes in the file name. Returns data allocated by xmalloc. * Warning: this calls getpw*. */ char * tilde_expand_filename(const char *filename, uid_t uid) { const char *path, *sep; char user[128], *ret; struct passwd *pw; u_int len, slash; if (*filename != '~') return (xstrdup(filename)); filename++; path = strchr(filename, '/'); if (path != NULL && path > filename) { /* ~user/path */ slash = path - filename; if (slash > sizeof(user) - 1) fatal("tilde_expand_filename: ~username too long"); memcpy(user, filename, slash); user[slash] = '\0'; if ((pw = getpwnam(user)) == NULL) fatal("tilde_expand_filename: No such user %s", user); } else if ((pw = getpwuid(uid)) == NULL) /* ~/path */ fatal("tilde_expand_filename: No such uid %ld", (long)uid); /* Make sure directory has a trailing '/' */ len = strlen(pw->pw_dir); if (len == 0 || pw->pw_dir[len - 1] != '/') sep = "/"; else sep = ""; /* Skip leading '/' from specified path */ if (path != NULL) filename = path + 1; if (xasprintf(&ret, "%s%s%s", pw->pw_dir, sep, filename) >= PATH_MAX) fatal("tilde_expand_filename: Path too long"); return (ret); } /* * Expand a string with a set of %[char] escapes. A number of escapes may be * specified as (char *escape_chars, char *replacement) pairs. The list must * be terminated by a NULL escape_char. Returns replaced string in memory * allocated by xmalloc. */ char * percent_expand(const char *string, ...) { #define EXPAND_MAX_KEYS 16 u_int num_keys, i, j; struct { const char *key; const char *repl; } keys[EXPAND_MAX_KEYS]; char buf[4096]; va_list ap; /* Gather keys */ va_start(ap, string); for (num_keys = 0; num_keys < EXPAND_MAX_KEYS; num_keys++) { keys[num_keys].key = va_arg(ap, char *); if (keys[num_keys].key == NULL) break; keys[num_keys].repl = va_arg(ap, char *); if (keys[num_keys].repl == NULL) fatal("%s: NULL replacement", __func__); } if (num_keys == EXPAND_MAX_KEYS && va_arg(ap, char *) != NULL) fatal("%s: too many keys", __func__); va_end(ap); /* Expand string */ *buf = '\0'; for (i = 0; *string != '\0'; string++) { if (*string != '%') { append: buf[i++] = *string; if (i >= sizeof(buf)) fatal("%s: string too long", __func__); buf[i] = '\0'; continue; } string++; /* %% case */ if (*string == '%') goto append; if (*string == '\0') fatal("%s: invalid format", __func__); for (j = 0; j < num_keys; j++) { if (strchr(keys[j].key, *string) != NULL) { i = strlcat(buf, keys[j].repl, sizeof(buf)); if (i >= sizeof(buf)) fatal("%s: string too long", __func__); break; } } if (j >= num_keys) fatal("%s: unknown key %%%c", __func__, *string); } return (xstrdup(buf)); #undef EXPAND_MAX_KEYS } int tun_open(int tun, int mode, char **ifname) { #if defined(CUSTOM_SYS_TUN_OPEN) return (sys_tun_open(tun, mode, ifname)); #elif defined(SSH_TUN_OPENBSD) struct ifreq ifr; char name[100]; int fd = -1, sock; const char *tunbase = "tun"; if (ifname != NULL) *ifname = NULL; if (mode == SSH_TUNMODE_ETHERNET) tunbase = "tap"; /* Open the tunnel device */ if (tun <= SSH_TUNID_MAX) { snprintf(name, sizeof(name), "/dev/%s%d", tunbase, tun); fd = open(name, O_RDWR); } else if (tun == SSH_TUNID_ANY) { for (tun = 100; tun >= 0; tun--) { snprintf(name, sizeof(name), "/dev/%s%d", tunbase, tun); if ((fd = open(name, O_RDWR)) >= 0) break; } } else { debug("%s: invalid tunnel %u", __func__, tun); return -1; } if (fd < 0) { debug("%s: %s open: %s", __func__, name, strerror(errno)); return -1; } debug("%s: %s mode %d fd %d", __func__, name, mode, fd); /* Bring interface up if it is not already */ snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d", tunbase, tun); if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1) goto failed; if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1) { debug("%s: get interface %s flags: %s", __func__, ifr.ifr_name, strerror(errno)); goto failed; } if (!(ifr.ifr_flags & IFF_UP)) { ifr.ifr_flags |= IFF_UP; if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1) { debug("%s: activate interface %s: %s", __func__, ifr.ifr_name, strerror(errno)); goto failed; } } if (ifname != NULL) *ifname = xstrdup(ifr.ifr_name); close(sock); return fd; failed: if (fd >= 0) close(fd); if (sock >= 0) close(sock); return -1; #else error("Tunnel interfaces are not supported on this platform"); return (-1); #endif } void sanitise_stdfd(void) { int nullfd, dupfd; if ((nullfd = dupfd = open(_PATH_DEVNULL, O_RDWR)) == -1) { fprintf(stderr, "Couldn't open /dev/null: %s\n", strerror(errno)); exit(1); } while (++dupfd <= STDERR_FILENO) { /* Only populate closed fds. */ if (fcntl(dupfd, F_GETFL) == -1 && errno == EBADF) { if (dup2(nullfd, dupfd) == -1) { fprintf(stderr, "dup2: %s\n", strerror(errno)); exit(1); } } } if (nullfd > STDERR_FILENO) close(nullfd); } char * tohex(const void *vp, size_t l) { const u_char *p = (const u_char *)vp; char b[3], *r; size_t i, hl; if (l > 65536) return xstrdup("tohex: length > 65536"); hl = l * 2 + 1; r = xcalloc(1, hl); for (i = 0; i < l; i++) { snprintf(b, sizeof(b), "%02x", p[i]); strlcat(r, b, hl); } return (r); } u_int64_t get_u64(const void *vp) { const u_char *p = (const u_char *)vp; u_int64_t v; v = (u_int64_t)p[0] << 56; v |= (u_int64_t)p[1] << 48; v |= (u_int64_t)p[2] << 40; v |= (u_int64_t)p[3] << 32; v |= (u_int64_t)p[4] << 24; v |= (u_int64_t)p[5] << 16; v |= (u_int64_t)p[6] << 8; v |= (u_int64_t)p[7]; return (v); } u_int32_t get_u32(const void *vp) { const u_char *p = (const u_char *)vp; u_int32_t v; v = (u_int32_t)p[0] << 24; v |= (u_int32_t)p[1] << 16; v |= (u_int32_t)p[2] << 8; v |= (u_int32_t)p[3]; return (v); } u_int32_t get_u32_le(const void *vp) { const u_char *p = (const u_char *)vp; u_int32_t v; v = (u_int32_t)p[0]; v |= (u_int32_t)p[1] << 8; v |= (u_int32_t)p[2] << 16; v |= (u_int32_t)p[3] << 24; return (v); } u_int16_t get_u16(const void *vp) { const u_char *p = (const u_char *)vp; u_int16_t v; v = (u_int16_t)p[0] << 8; v |= (u_int16_t)p[1]; return (v); } void put_u64(void *vp, u_int64_t v) { u_char *p = (u_char *)vp; p[0] = (u_char)(v >> 56) & 0xff; p[1] = (u_char)(v >> 48) & 0xff; p[2] = (u_char)(v >> 40) & 0xff; p[3] = (u_char)(v >> 32) & 0xff; p[4] = (u_char)(v >> 24) & 0xff; p[5] = (u_char)(v >> 16) & 0xff; p[6] = (u_char)(v >> 8) & 0xff; p[7] = (u_char)v & 0xff; } void put_u32(void *vp, u_int32_t v) { u_char *p = (u_char *)vp; p[0] = (u_char)(v >> 24) & 0xff; p[1] = (u_char)(v >> 16) & 0xff; p[2] = (u_char)(v >> 8) & 0xff; p[3] = (u_char)v & 0xff; } void put_u32_le(void *vp, u_int32_t v) { u_char *p = (u_char *)vp; p[0] = (u_char)v & 0xff; p[1] = (u_char)(v >> 8) & 0xff; p[2] = (u_char)(v >> 16) & 0xff; p[3] = (u_char)(v >> 24) & 0xff; } void put_u16(void *vp, u_int16_t v) { u_char *p = (u_char *)vp; p[0] = (u_char)(v >> 8) & 0xff; p[1] = (u_char)v & 0xff; } void ms_subtract_diff(struct timeval *start, int *ms) { struct timeval diff, finish; monotime_tv(&finish); timersub(&finish, start, &diff); *ms -= (diff.tv_sec * 1000) + (diff.tv_usec / 1000); } void ms_to_timeval(struct timeval *tv, int ms) { if (ms < 0) ms = 0; tv->tv_sec = ms / 1000; tv->tv_usec = (ms % 1000) * 1000; } void monotime_ts(struct timespec *ts) { struct timeval tv; #if defined(HAVE_CLOCK_GETTIME) && (defined(CLOCK_BOOTTIME) || \ defined(CLOCK_MONOTONIC) || defined(CLOCK_REALTIME)) static int gettime_failed = 0; if (!gettime_failed) { # ifdef CLOCK_BOOTTIME if (clock_gettime(CLOCK_BOOTTIME, ts) == 0) return; # endif /* CLOCK_BOOTTIME */ # ifdef CLOCK_MONOTONIC if (clock_gettime(CLOCK_MONOTONIC, ts) == 0) return; # endif /* CLOCK_MONOTONIC */ # ifdef CLOCK_REALTIME /* Not monotonic, but we're almost out of options here. */ if (clock_gettime(CLOCK_REALTIME, ts) == 0) return; # endif /* CLOCK_REALTIME */ debug3("clock_gettime: %s", strerror(errno)); gettime_failed = 1; } #endif /* HAVE_CLOCK_GETTIME && (BOOTTIME || MONOTONIC || REALTIME) */ gettimeofday(&tv, NULL); ts->tv_sec = tv.tv_sec; ts->tv_nsec = (long)tv.tv_usec * 1000; } void monotime_tv(struct timeval *tv) { struct timespec ts; monotime_ts(&ts); tv->tv_sec = ts.tv_sec; tv->tv_usec = ts.tv_nsec / 1000; } time_t monotime(void) { struct timespec ts; monotime_ts(&ts); return ts.tv_sec; } double monotime_double(void) { struct timespec ts; monotime_ts(&ts); return ts.tv_sec + ((double)ts.tv_nsec / 1000000000); } void bandwidth_limit_init(struct bwlimit *bw, u_int64_t kbps, size_t buflen) { bw->buflen = buflen; bw->rate = kbps; bw->thresh = bw->rate; bw->lamt = 0; timerclear(&bw->bwstart); timerclear(&bw->bwend); } /* Callback from read/write loop to insert bandwidth-limiting delays */ void bandwidth_limit(struct bwlimit *bw, size_t read_len) { u_int64_t waitlen; struct timespec ts, rm; if (!timerisset(&bw->bwstart)) { monotime_tv(&bw->bwstart); return; } bw->lamt += read_len; if (bw->lamt < bw->thresh) return; monotime_tv(&bw->bwend); timersub(&bw->bwend, &bw->bwstart, &bw->bwend); if (!timerisset(&bw->bwend)) return; bw->lamt *= 8; waitlen = (double)1000000L * bw->lamt / bw->rate; bw->bwstart.tv_sec = waitlen / 1000000L; bw->bwstart.tv_usec = waitlen % 1000000L; if (timercmp(&bw->bwstart, &bw->bwend, >)) { timersub(&bw->bwstart, &bw->bwend, &bw->bwend); /* Adjust the wait time */ if (bw->bwend.tv_sec) { bw->thresh /= 2; if (bw->thresh < bw->buflen / 4) bw->thresh = bw->buflen / 4; } else if (bw->bwend.tv_usec < 10000) { bw->thresh *= 2; if (bw->thresh > bw->buflen * 8) bw->thresh = bw->buflen * 8; } TIMEVAL_TO_TIMESPEC(&bw->bwend, &ts); while (nanosleep(&ts, &rm) == -1) { if (errno != EINTR) break; ts = rm; } } bw->lamt = 0; monotime_tv(&bw->bwstart); } /* Make a template filename for mk[sd]temp() */ void mktemp_proto(char *s, size_t len) { const char *tmpdir; int r; if ((tmpdir = getenv("TMPDIR")) != NULL) { r = snprintf(s, len, "%s/ssh-XXXXXXXXXXXX", tmpdir); if (r > 0 && (size_t)r < len) return; } r = snprintf(s, len, "/tmp/ssh-XXXXXXXXXXXX"); if (r < 0 || (size_t)r >= len) fatal("%s: template string too short", __func__); } static const struct { const char *name; int value; } ipqos[] = { { "none", INT_MAX }, /* can't use 0 here; that's CS0 */ { "af11", IPTOS_DSCP_AF11 }, { "af12", IPTOS_DSCP_AF12 }, { "af13", IPTOS_DSCP_AF13 }, { "af21", IPTOS_DSCP_AF21 }, { "af22", IPTOS_DSCP_AF22 }, { "af23", IPTOS_DSCP_AF23 }, { "af31", IPTOS_DSCP_AF31 }, { "af32", IPTOS_DSCP_AF32 }, { "af33", IPTOS_DSCP_AF33 }, { "af41", IPTOS_DSCP_AF41 }, { "af42", IPTOS_DSCP_AF42 }, { "af43", IPTOS_DSCP_AF43 }, { "cs0", IPTOS_DSCP_CS0 }, { "cs1", IPTOS_DSCP_CS1 }, { "cs2", IPTOS_DSCP_CS2 }, { "cs3", IPTOS_DSCP_CS3 }, { "cs4", IPTOS_DSCP_CS4 }, { "cs5", IPTOS_DSCP_CS5 }, { "cs6", IPTOS_DSCP_CS6 }, { "cs7", IPTOS_DSCP_CS7 }, { "ef", IPTOS_DSCP_EF }, { "lowdelay", IPTOS_LOWDELAY }, { "throughput", IPTOS_THROUGHPUT }, { "reliability", IPTOS_RELIABILITY }, { NULL, -1 } }; int parse_ipqos(const char *cp) { u_int i; char *ep; long val; if (cp == NULL) return -1; for (i = 0; ipqos[i].name != NULL; i++) { if (strcasecmp(cp, ipqos[i].name) == 0) return ipqos[i].value; } /* Try parsing as an integer */ val = strtol(cp, &ep, 0); if (*cp == '\0' || *ep != '\0' || val < 0 || val > 255) return -1; return val; } const char * iptos2str(int iptos) { int i; static char iptos_str[sizeof "0xff"]; for (i = 0; ipqos[i].name != NULL; i++) { if (ipqos[i].value == iptos) return ipqos[i].name; } snprintf(iptos_str, sizeof iptos_str, "0x%02x", iptos); return iptos_str; } void lowercase(char *s) { for (; *s; s++) *s = tolower((u_char)*s); } int unix_listener(const char *path, int backlog, int unlink_first) { struct sockaddr_un sunaddr; int saved_errno, sock; memset(&sunaddr, 0, sizeof(sunaddr)); sunaddr.sun_family = AF_UNIX; if (strlcpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path)) >= sizeof(sunaddr.sun_path)) { error("%s: path \"%s\" too long for Unix domain socket", __func__, path); errno = ENAMETOOLONG; return -1; } sock = socket(PF_UNIX, SOCK_STREAM, 0); if (sock < 0) { saved_errno = errno; error("%s: socket: %.100s", __func__, strerror(errno)); errno = saved_errno; return -1; } if (unlink_first == 1) { if (unlink(path) != 0 && errno != ENOENT) error("unlink(%s): %.100s", path, strerror(errno)); } if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) { saved_errno = errno; error("%s: cannot bind to path %s: %s", __func__, path, strerror(errno)); close(sock); errno = saved_errno; return -1; } if (listen(sock, backlog) < 0) { saved_errno = errno; error("%s: cannot listen on path %s: %s", __func__, path, strerror(errno)); close(sock); unlink(path); errno = saved_errno; return -1; } return sock; } void sock_set_v6only(int s) { #if defined(IPV6_V6ONLY) && !defined(__OpenBSD__) int on = 1; debug3("%s: set socket %d IPV6_V6ONLY", __func__, s); if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) == -1) error("setsockopt IPV6_V6ONLY: %s", strerror(errno)); #endif } /* * Compares two strings that maybe be NULL. Returns non-zero if strings * are both NULL or are identical, returns zero otherwise. */ static int strcmp_maybe_null(const char *a, const char *b) { if ((a == NULL && b != NULL) || (a != NULL && b == NULL)) return 0; if (a != NULL && strcmp(a, b) != 0) return 0; return 1; } /* * Compare two forwards, returning non-zero if they are identical or * zero otherwise. */ int forward_equals(const struct Forward *a, const struct Forward *b) { if (strcmp_maybe_null(a->listen_host, b->listen_host) == 0) return 0; if (a->listen_port != b->listen_port) return 0; if (strcmp_maybe_null(a->listen_path, b->listen_path) == 0) return 0; if (strcmp_maybe_null(a->connect_host, b->connect_host) == 0) return 0; if (a->connect_port != b->connect_port) return 0; if (strcmp_maybe_null(a->connect_path, b->connect_path) == 0) return 0; /* allocated_port and handle are not checked */ return 1; } /* returns 1 if process is already daemonized, 0 otherwise */ int daemonized(void) { int fd; if ((fd = open(_PATH_TTY, O_RDONLY | O_NOCTTY)) >= 0) { close(fd); return 0; /* have controlling terminal */ } if (getppid() != 1) return 0; /* parent is not init */ if (getsid(0) != getpid()) return 0; /* not session leader */ debug3("already daemonized"); return 1; } /* * Splits 's' into an argument vector. Handles quoted string and basic * escape characters (\\, \", \'). Caller must free the argument vector * and its members. */ int argv_split(const char *s, int *argcp, char ***argvp) { int r = SSH_ERR_INTERNAL_ERROR; int argc = 0, quote, i, j; char *arg, **argv = xcalloc(1, sizeof(*argv)); *argvp = NULL; *argcp = 0; for (i = 0; s[i] != '\0'; i++) { /* Skip leading whitespace */ if (s[i] == ' ' || s[i] == '\t') continue; /* Start of a token */ quote = 0; if (s[i] == '\\' && (s[i + 1] == '\'' || s[i + 1] == '\"' || s[i + 1] == '\\')) i++; else if (s[i] == '\'' || s[i] == '"') quote = s[i++]; argv = xreallocarray(argv, (argc + 2), sizeof(*argv)); arg = argv[argc++] = xcalloc(1, strlen(s + i) + 1); argv[argc] = NULL; /* Copy the token in, removing escapes */ for (j = 0; s[i] != '\0'; i++) { if (s[i] == '\\') { if (s[i + 1] == '\'' || s[i + 1] == '\"' || s[i + 1] == '\\') { i++; /* Skip '\' */ arg[j++] = s[i]; } else { /* Unrecognised escape */ arg[j++] = s[i]; } } else if (quote == 0 && (s[i] == ' ' || s[i] == '\t')) break; /* done */ else if (quote != 0 && s[i] == quote) break; /* done */ else arg[j++] = s[i]; } if (s[i] == '\0') { if (quote != 0) { /* Ran out of string looking for close quote */ r = SSH_ERR_INVALID_FORMAT; goto out; } break; } } /* Success */ *argcp = argc; *argvp = argv; argc = 0; argv = NULL; r = 0; out: if (argc != 0 && argv != NULL) { for (i = 0; i < argc; i++) free(argv[i]); free(argv); } return r; } /* * Reassemble an argument vector into a string, quoting and escaping as * necessary. Caller must free returned string. */ char * argv_assemble(int argc, char **argv) { int i, j, ws, r; char c, *ret; struct sshbuf *buf, *arg; if ((buf = sshbuf_new()) == NULL || (arg = sshbuf_new()) == NULL) fatal("%s: sshbuf_new failed", __func__); for (i = 0; i < argc; i++) { ws = 0; sshbuf_reset(arg); for (j = 0; argv[i][j] != '\0'; j++) { r = 0; c = argv[i][j]; switch (c) { case ' ': case '\t': ws = 1; r = sshbuf_put_u8(arg, c); break; case '\\': case '\'': case '"': if ((r = sshbuf_put_u8(arg, '\\')) != 0) break; /* FALLTHROUGH */ default: r = sshbuf_put_u8(arg, c); break; } if (r != 0) fatal("%s: sshbuf_put_u8: %s", __func__, ssh_err(r)); } if ((i != 0 && (r = sshbuf_put_u8(buf, ' ')) != 0) || (ws != 0 && (r = sshbuf_put_u8(buf, '"')) != 0) || (r = sshbuf_putb(buf, arg)) != 0 || (ws != 0 && (r = sshbuf_put_u8(buf, '"')) != 0)) fatal("%s: buffer error: %s", __func__, ssh_err(r)); } if ((ret = malloc(sshbuf_len(buf) + 1)) == NULL) fatal("%s: malloc failed", __func__); memcpy(ret, sshbuf_ptr(buf), sshbuf_len(buf)); ret[sshbuf_len(buf)] = '\0'; sshbuf_free(buf); sshbuf_free(arg); return ret; } /* Returns 0 if pid exited cleanly, non-zero otherwise */ int exited_cleanly(pid_t pid, const char *tag, const char *cmd, int quiet) { int status; while (waitpid(pid, &status, 0) == -1) { if (errno != EINTR) { error("%s: waitpid: %s", tag, strerror(errno)); return -1; } } if (WIFSIGNALED(status)) { error("%s %s exited on signal %d", tag, cmd, WTERMSIG(status)); return -1; } else if (WEXITSTATUS(status) != 0) { do_log2(quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_INFO, "%s %s failed, status %d", tag, cmd, WEXITSTATUS(status)); return -1; } return 0; } /* * 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 safe_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 safe_path() that accepts an open file descriptor to * avoid races. * * Returns 0 on success and -1 on failure */ int safe_path_fd(int fd, const char *file, struct passwd *pw, char *err, size_t errlen) { struct stat st; /* check the open file to avoid races */ if (fstat(fd, &st) < 0) { snprintf(err, errlen, "cannot stat file %s: %s", file, strerror(errno)); return -1; } return safe_path(file, &st, pw->pw_dir, pw->pw_uid, err, errlen); } /* * Sets the value of the given variable in the environment. If the variable * already exists, its value is overridden. */ void child_set_env(char ***envp, u_int *envsizep, const char *name, const char *value) { char **env; u_int envsize; u_int i, namelen; if (strchr(name, '=') != NULL) { error("Invalid environment variable \"%.100s\"", name); return; } /* * If we're passed an uninitialized list, allocate a single null * entry before continuing. */ if (*envp == NULL && *envsizep == 0) { *envp = xmalloc(sizeof(char *)); *envp[0] = NULL; *envsizep = 1; } /* * Find the slot where the value should be stored. If the variable * already exists, we reuse the slot; otherwise we append a new slot * at the end of the array, expanding if necessary. */ env = *envp; namelen = strlen(name); for (i = 0; env[i]; i++) if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=') break; if (env[i]) { /* Reuse the slot. */ free(env[i]); } else { /* New variable. Expand if necessary. */ envsize = *envsizep; if (i >= envsize - 1) { if (envsize >= 1000) fatal("child_set_env: too many env vars"); envsize += 50; env = (*envp) = xreallocarray(env, envsize, sizeof(char *)); *envsizep = envsize; } /* Need to set the NULL pointer at end of array beyond the new slot. */ env[i + 1] = NULL; } /* Allocate space and format the variable in the appropriate slot. */ /* XXX xasprintf */ env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1); snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value); } /* * Check and optionally lowercase a domain name, also removes trailing '.' * Returns 1 on success and 0 on failure, storing an error message in errstr. */ int valid_domain(char *name, int makelower, const char **errstr) { size_t i, l = strlen(name); u_char c, last = '\0'; static char errbuf[256]; if (l == 0) { strlcpy(errbuf, "empty domain name", sizeof(errbuf)); goto bad; } if (!isalpha((u_char)name[0]) && !isdigit((u_char)name[0])) { snprintf(errbuf, sizeof(errbuf), "domain name \"%.100s\" " "starts with invalid character", name); goto bad; } for (i = 0; i < l; i++) { c = tolower((u_char)name[i]); if (makelower) name[i] = (char)c; if (last == '.' && c == '.') { snprintf(errbuf, sizeof(errbuf), "domain name " "\"%.100s\" contains consecutive separators", name); goto bad; } if (c != '.' && c != '-' && !isalnum(c) && c != '_') /* technically invalid, but common */ { snprintf(errbuf, sizeof(errbuf), "domain name " "\"%.100s\" contains invalid characters", name); goto bad; } last = c; } if (name[l - 1] == '.') name[l - 1] = '\0'; if (errstr != NULL) *errstr = NULL; return 1; bad: if (errstr != NULL) *errstr = errbuf; return 0; } /* * Verify that a environment variable name (not including initial '$') is * valid; consisting of one or more alphanumeric or underscore characters only. * Returns 1 on valid, 0 otherwise. */ int valid_env_name(const char *name) { const char *cp; if (name[0] == '\0') return 0; for (cp = name; *cp != '\0'; cp++) { if (!isalnum((u_char)*cp) && *cp != '_') return 0; } return 1; } const char * atoi_err(const char *nptr, int *val) { const char *errstr = NULL; long long num; if (nptr == NULL || *nptr == '\0') return "missing"; num = strtonum(nptr, 0, INT_MAX, &errstr); if (errstr == NULL) *val = (int)num; return errstr; } int parse_absolute_time(const char *s, uint64_t *tp) { struct tm tm; time_t tt; char buf[32], *fmt; *tp = 0; /* * POSIX strptime says "The application shall ensure that there * is white-space or other non-alphanumeric characters between * any two conversion specifications" so arrange things this way. */ switch (strlen(s)) { case 8: /* YYYYMMDD */ fmt = "%Y-%m-%d"; snprintf(buf, sizeof(buf), "%.4s-%.2s-%.2s", s, s + 4, s + 6); break; case 12: /* YYYYMMDDHHMM */ fmt = "%Y-%m-%dT%H:%M"; snprintf(buf, sizeof(buf), "%.4s-%.2s-%.2sT%.2s:%.2s", s, s + 4, s + 6, s + 8, s + 10); break; case 14: /* YYYYMMDDHHMMSS */ fmt = "%Y-%m-%dT%H:%M:%S"; snprintf(buf, sizeof(buf), "%.4s-%.2s-%.2sT%.2s:%.2s:%.2s", s, s + 4, s + 6, s + 8, s + 10, s + 12); break; default: return SSH_ERR_INVALID_FORMAT; } memset(&tm, 0, sizeof(tm)); if (strptime(buf, fmt, &tm) == NULL) return SSH_ERR_INVALID_FORMAT; if ((tt = mktime(&tm)) < 0) return SSH_ERR_INVALID_FORMAT; /* success */ *tp = (uint64_t)tt; return 0; } void format_absolute_time(uint64_t t, char *buf, size_t len) { time_t tt = t > INT_MAX ? INT_MAX : t; /* XXX revisit in 2038 :P */ struct tm tm; localtime_r(&tt, &tm); strftime(buf, len, "%Y-%m-%dT%H:%M:%S", &tm); } diff --git a/crypto/openssh/sshconnect.c b/crypto/openssh/sshconnect.c index 2776be920a2c..b50029de71b8 100644 --- a/crypto/openssh/sshconnect.c +++ b/crypto/openssh/sshconnect.c @@ -1,1585 +1,1584 @@ /* $OpenBSD: sshconnect.c,v 1.305 2018/09/20 03:30:44 djm Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland * All rights reserved * Code to connect to a remote host, and to perform the client side of the * login (authentication) dialog. * * 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" __RCSID("$FreeBSD$"); #include #include #include #include #ifdef HAVE_SYS_TIME_H # include #endif #include #include #include -#include #include #include #include #include #ifdef HAVE_PATHS_H #include #endif #include #ifdef HAVE_POLL_H #include #endif #include #include #include #include #include #include #ifdef HAVE_IFADDRS_H # include #endif #include "xmalloc.h" #include "hostfile.h" #include "ssh.h" #include "sshbuf.h" #include "packet.h" #include "compat.h" #include "sshkey.h" #include "sshconnect.h" #include "hostfile.h" #include "log.h" #include "misc.h" #include "readconf.h" #include "atomicio.h" #include "dns.h" #include "monitor_fdpass.h" #include "ssh2.h" #include "version.h" #include "authfile.h" #include "ssherr.h" #include "authfd.h" char *client_version_string = NULL; char *server_version_string = NULL; struct sshkey *previous_host_key = NULL; static int matching_host_key_dns = 0; static pid_t proxy_command_pid = 0; /* import */ extern Options options; extern char *__progname; static int show_other_keys(struct hostkeys *, struct sshkey *); static void warn_changed_key(struct sshkey *); /* Expand a proxy command */ static char * expand_proxy_command(const char *proxy_command, const char *user, const char *host, int port) { char *tmp, *ret, strport[NI_MAXSERV]; snprintf(strport, sizeof strport, "%d", port); xasprintf(&tmp, "exec %s", proxy_command); ret = percent_expand(tmp, "h", host, "p", strport, "r", options.user, (char *)NULL); free(tmp); return ret; } /* * Connect to the given ssh server using a proxy command that passes a * a connected fd back to us. */ static int ssh_proxy_fdpass_connect(struct ssh *ssh, const char *host, u_short port, const char *proxy_command) { char *command_string; int sp[2], sock; pid_t pid; char *shell; if ((shell = getenv("SHELL")) == NULL) shell = _PATH_BSHELL; if (socketpair(AF_UNIX, SOCK_STREAM, 0, sp) < 0) fatal("Could not create socketpair to communicate with " "proxy dialer: %.100s", strerror(errno)); command_string = expand_proxy_command(proxy_command, options.user, host, port); debug("Executing proxy dialer command: %.500s", command_string); /* Fork and execute the proxy command. */ if ((pid = fork()) == 0) { char *argv[10]; close(sp[1]); /* Redirect stdin and stdout. */ if (sp[0] != 0) { if (dup2(sp[0], 0) < 0) perror("dup2 stdin"); } if (sp[0] != 1) { if (dup2(sp[0], 1) < 0) perror("dup2 stdout"); } if (sp[0] >= 2) close(sp[0]); /* * Stderr is left as it is so that error messages get * printed on the user's terminal. */ argv[0] = shell; argv[1] = "-c"; argv[2] = command_string; argv[3] = NULL; /* * Execute the proxy command. * Note that we gave up any extra privileges above. */ execv(argv[0], argv); perror(argv[0]); exit(1); } /* Parent. */ if (pid < 0) fatal("fork failed: %.100s", strerror(errno)); close(sp[0]); free(command_string); if ((sock = mm_receive_fd(sp[1])) == -1) fatal("proxy dialer did not pass back a connection"); close(sp[1]); while (waitpid(pid, NULL, 0) == -1) if (errno != EINTR) fatal("Couldn't wait for child: %s", strerror(errno)); /* Set the connection file descriptors. */ if (ssh_packet_set_connection(ssh, sock, sock) == NULL) return -1; /* ssh_packet_set_connection logs error */ return 0; } /* * Connect to the given ssh server using a proxy command. */ static int ssh_proxy_connect(struct ssh *ssh, const char *host, u_short port, const char *proxy_command) { char *command_string; int pin[2], pout[2]; pid_t pid; char *shell; if ((shell = getenv("SHELL")) == NULL || *shell == '\0') shell = _PATH_BSHELL; /* Create pipes for communicating with the proxy. */ if (pipe(pin) < 0 || pipe(pout) < 0) fatal("Could not create pipes to communicate with the proxy: %.100s", strerror(errno)); command_string = expand_proxy_command(proxy_command, options.user, host, port); debug("Executing proxy command: %.500s", command_string); /* Fork and execute the proxy command. */ if ((pid = fork()) == 0) { char *argv[10]; /* Redirect stdin and stdout. */ close(pin[1]); if (pin[0] != 0) { if (dup2(pin[0], 0) < 0) perror("dup2 stdin"); close(pin[0]); } close(pout[0]); if (dup2(pout[1], 1) < 0) perror("dup2 stdout"); /* Cannot be 1 because pin allocated two descriptors. */ close(pout[1]); /* Stderr is left as it is so that error messages get printed on the user's terminal. */ argv[0] = shell; argv[1] = "-c"; argv[2] = command_string; argv[3] = NULL; /* Execute the proxy command. Note that we gave up any extra privileges above. */ signal(SIGPIPE, SIG_DFL); execv(argv[0], argv); perror(argv[0]); exit(1); } /* Parent. */ if (pid < 0) fatal("fork failed: %.100s", strerror(errno)); else proxy_command_pid = pid; /* save pid to clean up later */ /* Close child side of the descriptors. */ close(pin[0]); close(pout[1]); /* Free the command name. */ free(command_string); /* Set the connection file descriptors. */ if (ssh_packet_set_connection(ssh, pout[0], pin[1]) == NULL) return -1; /* ssh_packet_set_connection logs error */ return 0; } void ssh_kill_proxy_command(void) { /* * Send SIGHUP to proxy command if used. We don't wait() in * case it hangs and instead rely on init to reap the child */ if (proxy_command_pid > 1) kill(proxy_command_pid, SIGHUP); } #ifdef HAVE_IFADDRS_H /* * Search a interface address list (returned from getifaddrs(3)) for an * address that matches the desired address family on the specified interface. * Returns 0 and fills in *resultp and *rlenp on success. Returns -1 on failure. */ static int check_ifaddrs(const char *ifname, int af, const struct ifaddrs *ifaddrs, struct sockaddr_storage *resultp, socklen_t *rlenp) { struct sockaddr_in6 *sa6; struct sockaddr_in *sa; struct in6_addr *v6addr; const struct ifaddrs *ifa; int allow_local; /* * Prefer addresses that are not loopback or linklocal, but use them * if nothing else matches. */ for (allow_local = 0; allow_local < 2; allow_local++) { for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) { if (ifa->ifa_addr == NULL || ifa->ifa_name == NULL || (ifa->ifa_flags & IFF_UP) == 0 || ifa->ifa_addr->sa_family != af || strcmp(ifa->ifa_name, options.bind_interface) != 0) continue; switch (ifa->ifa_addr->sa_family) { case AF_INET: sa = (struct sockaddr_in *)ifa->ifa_addr; if (!allow_local && sa->sin_addr.s_addr == htonl(INADDR_LOOPBACK)) continue; if (*rlenp < sizeof(struct sockaddr_in)) { error("%s: v4 addr doesn't fit", __func__); return -1; } *rlenp = sizeof(struct sockaddr_in); memcpy(resultp, sa, *rlenp); return 0; case AF_INET6: sa6 = (struct sockaddr_in6 *)ifa->ifa_addr; v6addr = &sa6->sin6_addr; if (!allow_local && (IN6_IS_ADDR_LINKLOCAL(v6addr) || IN6_IS_ADDR_LOOPBACK(v6addr))) continue; if (*rlenp < sizeof(struct sockaddr_in6)) { error("%s: v6 addr doesn't fit", __func__); return -1; } *rlenp = sizeof(struct sockaddr_in6); memcpy(resultp, sa6, *rlenp); return 0; } } } return -1; } #endif /* * Creates a socket for use as the ssh connection. */ static int ssh_create_socket(struct addrinfo *ai) { int sock, r; struct sockaddr_storage bindaddr; socklen_t bindaddrlen = 0; struct addrinfo hints, *res = NULL; #ifdef HAVE_IFADDRS_H struct ifaddrs *ifaddrs = NULL; #endif char ntop[NI_MAXHOST]; sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); if (sock < 0) { error("socket: %s", strerror(errno)); return -1; } fcntl(sock, F_SETFD, FD_CLOEXEC); /* Bind the socket to an alternative local IP address */ if (options.bind_address == NULL && options.bind_interface == NULL) return sock; if (options.bind_address != NULL) { memset(&hints, 0, sizeof(hints)); hints.ai_family = ai->ai_family; hints.ai_socktype = ai->ai_socktype; hints.ai_protocol = ai->ai_protocol; hints.ai_flags = AI_PASSIVE; if ((r = getaddrinfo(options.bind_address, NULL, &hints, &res)) != 0) { error("getaddrinfo: %s: %s", options.bind_address, ssh_gai_strerror(r)); goto fail; } if (res == NULL) { error("getaddrinfo: no addrs"); goto fail; } if (res->ai_addrlen > sizeof(bindaddr)) { error("%s: addr doesn't fit", __func__); goto fail; } memcpy(&bindaddr, res->ai_addr, res->ai_addrlen); bindaddrlen = res->ai_addrlen; } else if (options.bind_interface != NULL) { #ifdef HAVE_IFADDRS_H if ((r = getifaddrs(&ifaddrs)) != 0) { error("getifaddrs: %s: %s", options.bind_interface, strerror(errno)); goto fail; } bindaddrlen = sizeof(bindaddr); if (check_ifaddrs(options.bind_interface, ai->ai_family, ifaddrs, &bindaddr, &bindaddrlen) != 0) { logit("getifaddrs: %s: no suitable addresses", options.bind_interface); goto fail; } #else error("BindInterface not supported on this platform."); #endif } if ((r = getnameinfo((struct sockaddr *)&bindaddr, bindaddrlen, ntop, sizeof(ntop), NULL, 0, NI_NUMERICHOST)) != 0) { error("%s: getnameinfo failed: %s", __func__, ssh_gai_strerror(r)); goto fail; } if (bind(sock, (struct sockaddr *)&bindaddr, bindaddrlen) != 0) { error("bind %s: %s", ntop, strerror(errno)); goto fail; } debug("%s: bound to %s", __func__, ntop); /* success */ goto out; fail: close(sock); sock = -1; out: if (res != NULL) freeaddrinfo(res); #ifdef HAVE_IFADDRS_H if (ifaddrs != NULL) freeifaddrs(ifaddrs); #endif return sock; } /* * Wait up to *timeoutp milliseconds for fd to be readable. Updates * *timeoutp with time remaining. * Returns 0 if fd ready or -1 on timeout or error (see errno). */ static int waitrfd(int fd, int *timeoutp) { struct pollfd pfd; struct timeval t_start; int oerrno, r; monotime_tv(&t_start); pfd.fd = fd; pfd.events = POLLIN; for (; *timeoutp >= 0;) { r = poll(&pfd, 1, *timeoutp); oerrno = errno; ms_subtract_diff(&t_start, timeoutp); errno = oerrno; if (r > 0) return 0; else if (r == -1 && errno != EAGAIN) return -1; else if (r == 0) break; } /* timeout */ errno = ETIMEDOUT; return -1; } static int timeout_connect(int sockfd, const struct sockaddr *serv_addr, socklen_t addrlen, int *timeoutp) { int optval = 0; socklen_t optlen = sizeof(optval); /* No timeout: just do a blocking connect() */ if (*timeoutp <= 0) return connect(sockfd, serv_addr, addrlen); set_nonblock(sockfd); if (connect(sockfd, serv_addr, addrlen) == 0) { /* Succeeded already? */ unset_nonblock(sockfd); return 0; } else if (errno != EINPROGRESS) return -1; if (waitrfd(sockfd, timeoutp) == -1) return -1; /* Completed or failed */ if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval, &optlen) == -1) { debug("getsockopt: %s", strerror(errno)); return -1; } if (optval != 0) { errno = optval; return -1; } unset_nonblock(sockfd); return 0; } /* * Opens a TCP/IP connection to the remote server on the given host. * The address of the remote host will be returned in hostaddr. * If port is 0, the default port will be used. * Connection_attempts specifies the maximum number of tries (one per * second). If proxy_command is non-NULL, it specifies the command (with %h * and %p substituted for host and port, respectively) to use to contact * the daemon. */ static int ssh_connect_direct(struct ssh *ssh, const char *host, struct addrinfo *aitop, struct sockaddr_storage *hostaddr, u_short port, int family, int connection_attempts, int *timeout_ms, int want_keepalive) { int on = 1; int oerrno, sock = -1, attempt; char ntop[NI_MAXHOST], strport[NI_MAXSERV]; struct addrinfo *ai; debug2("%s", __func__); memset(ntop, 0, sizeof(ntop)); memset(strport, 0, sizeof(strport)); for (attempt = 0; attempt < connection_attempts; attempt++) { if (attempt > 0) { /* Sleep a moment before retrying. */ sleep(1); debug("Trying again..."); } /* * Loop through addresses for this host, and try each one in * sequence until the connection succeeds. */ for (ai = aitop; ai; ai = ai->ai_next) { if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) { errno = EAFNOSUPPORT; continue; } if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { oerrno = errno; error("%s: getnameinfo failed", __func__); errno = oerrno; continue; } debug("Connecting to %.200s [%.100s] port %s.", host, ntop, strport); /* Create a socket for connecting. */ sock = ssh_create_socket(ai); if (sock < 0) { /* Any error is already output */ errno = 0; continue; } if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen, timeout_ms) >= 0) { /* Successful connection. */ memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen); break; } else { oerrno = errno; debug("connect to address %s port %s: %s", ntop, strport, strerror(errno)); close(sock); sock = -1; errno = oerrno; } } if (sock != -1) break; /* Successful connection. */ } /* Return failure if we didn't get a successful connection. */ if (sock == -1) { error("ssh: connect to host %s port %s: %s", host, strport, errno == 0 ? "failure" : strerror(errno)); return -1; } debug("Connection established."); /* Set SO_KEEPALIVE if requested. */ if (want_keepalive && setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on, sizeof(on)) < 0) error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); /* Set the connection. */ if (ssh_packet_set_connection(ssh, sock, sock) == NULL) return -1; /* ssh_packet_set_connection logs error */ return 0; } int ssh_connect(struct ssh *ssh, const char *host, struct addrinfo *addrs, struct sockaddr_storage *hostaddr, u_short port, int family, int connection_attempts, int *timeout_ms, int want_keepalive) { if (options.proxy_command == NULL) { return ssh_connect_direct(ssh, host, addrs, hostaddr, port, family, connection_attempts, timeout_ms, want_keepalive); } else if (strcmp(options.proxy_command, "-") == 0) { if ((ssh_packet_set_connection(ssh, STDIN_FILENO, STDOUT_FILENO)) == NULL) return -1; /* ssh_packet_set_connection logs error */ return 0; } else if (options.proxy_use_fdpass) { return ssh_proxy_fdpass_connect(ssh, host, port, options.proxy_command); } return ssh_proxy_connect(ssh, host, port, options.proxy_command); } static void send_client_banner(int connection_out, int minor1) { /* Send our own protocol version identification. */ xasprintf(&client_version_string, "SSH-%d.%d-%.100s%s%s\n", PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, SSH_VERSION, *options.version_addendum == '\0' ? "" : " ", options.version_addendum); if (atomicio(vwrite, connection_out, client_version_string, strlen(client_version_string)) != strlen(client_version_string)) fatal("write: %.100s", strerror(errno)); chop(client_version_string); debug("Local version string %.100s", client_version_string); } /* * Waits for the server identification string, and sends our own * identification string. */ void ssh_exchange_identification(int timeout_ms) { char buf[256], remote_version[256]; /* must be same size! */ int remote_major, remote_minor, mismatch; int connection_in = packet_get_connection_in(); int connection_out = packet_get_connection_out(); u_int i, n; size_t len; int rc; send_client_banner(connection_out, 0); /* Read other side's version identification. */ for (n = 0;;) { for (i = 0; i < sizeof(buf) - 1; i++) { if (timeout_ms > 0) { rc = waitrfd(connection_in, &timeout_ms); if (rc == -1 && errno == ETIMEDOUT) { fatal("Connection timed out during " "banner exchange"); } else if (rc == -1) { fatal("%s: %s", __func__, strerror(errno)); } } len = atomicio(read, connection_in, &buf[i], 1); if (len != 1 && errno == EPIPE) fatal("ssh_exchange_identification: " "Connection closed by remote host"); else if (len != 1) fatal("ssh_exchange_identification: " "read: %.100s", strerror(errno)); if (buf[i] == '\r') { buf[i] = '\n'; buf[i + 1] = 0; continue; /**XXX wait for \n */ } if (buf[i] == '\n') { buf[i + 1] = 0; break; } if (++n > 65536) fatal("ssh_exchange_identification: " "No banner received"); } buf[sizeof(buf) - 1] = 0; if (strncmp(buf, "SSH-", 4) == 0) break; debug("ssh_exchange_identification: %s", buf); } server_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(server_version_string, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor, remote_version) != 3) fatal("Bad remote protocol version identification: '%.100s'", buf); debug("Remote protocol version %d.%d, remote software version %.100s", remote_major, remote_minor, remote_version); active_state->compat = compat_datafellows(remote_version); mismatch = 0; switch (remote_major) { case 2: break; case 1: if (remote_minor != 99) mismatch = 1; break; default: mismatch = 1; break; } if (mismatch) fatal("Protocol major versions differ: %d vs. %d", PROTOCOL_MAJOR_2, remote_major); if ((datafellows & SSH_BUG_RSASIGMD5) != 0) logit("Server version \"%.100s\" uses unsafe RSA signature " "scheme; disabling use of RSA keys", remote_version); chop(server_version_string); } /* defaults to 'no' */ static int confirm(const char *prompt) { const char *msg, *again = "Please type 'yes' or 'no': "; char *p; int ret = -1; if (options.batch_mode) return 0; for (msg = prompt;;msg = again) { p = read_passphrase(msg, RP_ECHO); if (p == NULL) return 0; p[strcspn(p, "\n")] = '\0'; if (p[0] == '\0' || strcasecmp(p, "no") == 0) ret = 0; else if (strcasecmp(p, "yes") == 0) ret = 1; free(p); if (ret != -1) return ret; } } static int check_host_cert(const char *host, const struct sshkey *key) { const char *reason; int r; if (sshkey_cert_check_authority(key, 1, 0, host, &reason) != 0) { error("%s", reason); return 0; } if (sshbuf_len(key->cert->critical) != 0) { error("Certificate for %s contains unsupported " "critical options(s)", host); return 0; } if ((r = sshkey_check_cert_sigtype(key, options.ca_sign_algorithms)) != 0) { logit("%s: certificate signature algorithm %s: %s", __func__, (key->cert == NULL || key->cert->signature_type == NULL) ? "(null)" : key->cert->signature_type, ssh_err(r)); return 0; } return 1; } static int sockaddr_is_local(struct sockaddr *hostaddr) { switch (hostaddr->sa_family) { case AF_INET: return (ntohl(((struct sockaddr_in *)hostaddr)-> sin_addr.s_addr) >> 24) == IN_LOOPBACKNET; case AF_INET6: return IN6_IS_ADDR_LOOPBACK( &(((struct sockaddr_in6 *)hostaddr)->sin6_addr)); default: return 0; } } /* * Prepare the hostname and ip address strings that are used to lookup * host keys in known_hosts files. These may have a port number appended. */ void get_hostfile_hostname_ipaddr(char *hostname, struct sockaddr *hostaddr, u_short port, char **hostfile_hostname, char **hostfile_ipaddr) { char ntop[NI_MAXHOST]; socklen_t addrlen; switch (hostaddr == NULL ? -1 : hostaddr->sa_family) { case -1: addrlen = 0; break; case AF_INET: addrlen = sizeof(struct sockaddr_in); break; case AF_INET6: addrlen = sizeof(struct sockaddr_in6); break; default: addrlen = sizeof(struct sockaddr); break; } /* * We don't have the remote ip-address for connections * using a proxy command */ if (hostfile_ipaddr != NULL) { if (options.proxy_command == NULL) { if (getnameinfo(hostaddr, addrlen, ntop, sizeof(ntop), NULL, 0, NI_NUMERICHOST) != 0) fatal("%s: getnameinfo failed", __func__); *hostfile_ipaddr = put_host_port(ntop, port); } else { *hostfile_ipaddr = xstrdup(""); } } /* * Allow the user to record the key under a different name or * differentiate a non-standard port. This is useful for ssh * tunneling over forwarded connections or if you run multiple * sshd's on different ports on the same machine. */ if (hostfile_hostname != NULL) { if (options.host_key_alias != NULL) { *hostfile_hostname = xstrdup(options.host_key_alias); debug("using hostkeyalias: %s", *hostfile_hostname); } else { *hostfile_hostname = put_host_port(hostname, port); } } } /* * check whether the supplied host key is valid, return -1 if the key * is not valid. user_hostfile[0] will not be updated if 'readonly' is true. */ #define RDRW 0 #define RDONLY 1 #define ROQUIET 2 static int check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, struct sshkey *host_key, int readonly, char **user_hostfiles, u_int num_user_hostfiles, char **system_hostfiles, u_int num_system_hostfiles) { HostStatus host_status; HostStatus ip_status; struct sshkey *raw_key = NULL; char *ip = NULL, *host = NULL; char hostline[1000], *hostp, *fp, *ra; char msg[1024]; const char *type; const struct hostkey_entry *host_found, *ip_found; int len, cancelled_forwarding = 0; int local = sockaddr_is_local(hostaddr); int r, want_cert = sshkey_is_cert(host_key), host_ip_differ = 0; int hostkey_trusted = 0; /* Known or explicitly accepted by user */ struct hostkeys *host_hostkeys, *ip_hostkeys; u_int i; /* * Force accepting of the host key for loopback/localhost. The * problem is that if the home directory is NFS-mounted to multiple * machines, localhost will refer to a different machine in each of * them, and the user will get bogus HOST_CHANGED warnings. This * essentially disables host authentication for localhost; however, * this is probably not a real problem. */ if (options.no_host_authentication_for_localhost == 1 && local && options.host_key_alias == NULL) { debug("Forcing accepting of host key for " "loopback/localhost."); return 0; } /* * Prepare the hostname and address strings used for hostkey lookup. * In some cases, these will have a port number appended. */ get_hostfile_hostname_ipaddr(hostname, hostaddr, port, &host, &ip); /* * Turn off check_host_ip if the connection is to localhost, via proxy * command or if we don't have a hostname to compare with */ if (options.check_host_ip && (local || strcmp(hostname, ip) == 0 || options.proxy_command != NULL)) options.check_host_ip = 0; host_hostkeys = init_hostkeys(); for (i = 0; i < num_user_hostfiles; i++) load_hostkeys(host_hostkeys, host, user_hostfiles[i]); for (i = 0; i < num_system_hostfiles; i++) load_hostkeys(host_hostkeys, host, system_hostfiles[i]); ip_hostkeys = NULL; if (!want_cert && options.check_host_ip) { ip_hostkeys = init_hostkeys(); for (i = 0; i < num_user_hostfiles; i++) load_hostkeys(ip_hostkeys, ip, user_hostfiles[i]); for (i = 0; i < num_system_hostfiles; i++) load_hostkeys(ip_hostkeys, ip, system_hostfiles[i]); } retry: /* Reload these as they may have changed on cert->key downgrade */ want_cert = sshkey_is_cert(host_key); type = sshkey_type(host_key); /* * Check if the host key is present in the user's list of known * hosts or in the systemwide list. */ host_status = check_key_in_hostkeys(host_hostkeys, host_key, &host_found); /* * Also perform check for the ip address, skip the check if we are * localhost, looking for a certificate, or the hostname was an ip * address to begin with. */ if (!want_cert && ip_hostkeys != NULL) { ip_status = check_key_in_hostkeys(ip_hostkeys, host_key, &ip_found); if (host_status == HOST_CHANGED && (ip_status != HOST_CHANGED || (ip_found != NULL && !sshkey_equal(ip_found->key, host_found->key)))) host_ip_differ = 1; } else ip_status = host_status; switch (host_status) { case HOST_OK: /* The host is known and the key matches. */ debug("Host '%.200s' is known and matches the %s host %s.", host, type, want_cert ? "certificate" : "key"); debug("Found %s in %s:%lu", want_cert ? "CA key" : "key", host_found->file, host_found->line); if (want_cert && !check_host_cert(options.host_key_alias == NULL ? hostname : options.host_key_alias, host_key)) goto fail; if (options.check_host_ip && ip_status == HOST_NEW) { if (readonly || want_cert) logit("%s host key for IP address " "'%.128s' not in list of known hosts.", type, ip); else if (!add_host_to_hostfile(user_hostfiles[0], ip, host_key, options.hash_known_hosts)) logit("Failed to add the %s host key for IP " "address '%.128s' to the list of known " "hosts (%.500s).", type, ip, user_hostfiles[0]); else logit("Warning: Permanently added the %s host " "key for IP address '%.128s' to the list " "of known hosts.", type, ip); } else if (options.visual_host_key) { fp = sshkey_fingerprint(host_key, options.fingerprint_hash, SSH_FP_DEFAULT); ra = sshkey_fingerprint(host_key, options.fingerprint_hash, SSH_FP_RANDOMART); if (fp == NULL || ra == NULL) fatal("%s: sshkey_fingerprint fail", __func__); logit("Host key fingerprint is %s\n%s", fp, ra); free(ra); free(fp); } hostkey_trusted = 1; break; case HOST_NEW: if (options.host_key_alias == NULL && port != 0 && port != SSH_DEFAULT_PORT) { debug("checking without port identifier"); if (check_host_key(hostname, hostaddr, 0, host_key, ROQUIET, user_hostfiles, num_user_hostfiles, system_hostfiles, num_system_hostfiles) == 0) { debug("found matching key w/out port"); break; } } if (readonly || want_cert) goto fail; /* The host is new. */ if (options.strict_host_key_checking == SSH_STRICT_HOSTKEY_YES) { /* * User has requested strict host key checking. We * will not add the host key automatically. The only * alternative left is to abort. */ error("No %s host key is known for %.200s and you " "have requested strict checking.", type, host); goto fail; } else if (options.strict_host_key_checking == SSH_STRICT_HOSTKEY_ASK) { char msg1[1024], msg2[1024]; if (show_other_keys(host_hostkeys, host_key)) snprintf(msg1, sizeof(msg1), "\nbut keys of different type are already" " known for this host."); else snprintf(msg1, sizeof(msg1), "."); /* The default */ fp = sshkey_fingerprint(host_key, options.fingerprint_hash, SSH_FP_DEFAULT); ra = sshkey_fingerprint(host_key, options.fingerprint_hash, SSH_FP_RANDOMART); if (fp == NULL || ra == NULL) fatal("%s: sshkey_fingerprint fail", __func__); msg2[0] = '\0'; if (options.verify_host_key_dns) { if (matching_host_key_dns) snprintf(msg2, sizeof(msg2), "Matching host key fingerprint" " found in DNS.\n"); else snprintf(msg2, sizeof(msg2), "No matching host key fingerprint" " found in DNS.\n"); } snprintf(msg, sizeof(msg), "The authenticity of host '%.200s (%s)' can't be " "established%s\n" "%s key fingerprint is %s.%s%s\n%s" "Are you sure you want to continue connecting " "(yes/no)? ", host, ip, msg1, type, fp, options.visual_host_key ? "\n" : "", options.visual_host_key ? ra : "", msg2); free(ra); free(fp); if (!confirm(msg)) goto fail; hostkey_trusted = 1; /* user explicitly confirmed */ } /* * If in "new" or "off" strict mode, add the key automatically * to the local known_hosts file. */ if (options.check_host_ip && ip_status == HOST_NEW) { snprintf(hostline, sizeof(hostline), "%s,%s", host, ip); hostp = hostline; if (options.hash_known_hosts) { /* Add hash of host and IP separately */ r = add_host_to_hostfile(user_hostfiles[0], host, host_key, options.hash_known_hosts) && add_host_to_hostfile(user_hostfiles[0], ip, host_key, options.hash_known_hosts); } else { /* Add unhashed "host,ip" */ r = add_host_to_hostfile(user_hostfiles[0], hostline, host_key, options.hash_known_hosts); } } else { r = add_host_to_hostfile(user_hostfiles[0], host, host_key, options.hash_known_hosts); hostp = host; } if (!r) logit("Failed to add the host to the list of known " "hosts (%.500s).", user_hostfiles[0]); else logit("Warning: Permanently added '%.200s' (%s) to the " "list of known hosts.", hostp, type); break; case HOST_REVOKED: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); error("@ WARNING: REVOKED HOST KEY DETECTED! @"); error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); error("The %s host key for %s is marked as revoked.", type, host); error("This could mean that a stolen key is being used to"); error("impersonate this host."); /* * If strict host key checking is in use, the user will have * to edit the key manually and we can only abort. */ if (options.strict_host_key_checking != SSH_STRICT_HOSTKEY_OFF) { error("%s host key for %.200s was revoked and you have " "requested strict checking.", type, host); goto fail; } goto continue_unsafe; case HOST_CHANGED: if (want_cert) { /* * This is only a debug() since it is valid to have * CAs with wildcard DNS matches that don't match * all hosts that one might visit. */ debug("Host certificate authority does not " "match %s in %s:%lu", CA_MARKER, host_found->file, host_found->line); goto fail; } if (readonly == ROQUIET) goto fail; if (options.check_host_ip && host_ip_differ) { char *key_msg; if (ip_status == HOST_NEW) key_msg = "is unknown"; else if (ip_status == HOST_OK) key_msg = "is unchanged"; else key_msg = "has a different value"; error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @"); error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); error("The %s host key for %s has changed,", type, host); error("and the key for the corresponding IP address %s", ip); error("%s. This could either mean that", key_msg); error("DNS SPOOFING is happening or the IP address for the host"); error("and its host key have changed at the same time."); if (ip_status != HOST_NEW) error("Offending key for IP in %s:%lu", ip_found->file, ip_found->line); } /* The host key has changed. */ warn_changed_key(host_key); error("Add correct host key in %.100s to get rid of this message.", user_hostfiles[0]); error("Offending %s key in %s:%lu", sshkey_type(host_found->key), host_found->file, host_found->line); /* * If strict host key checking is in use, the user will have * to edit the key manually and we can only abort. */ if (options.strict_host_key_checking != SSH_STRICT_HOSTKEY_OFF) { error("%s host key for %.200s has changed and you have " "requested strict checking.", type, host); goto fail; } continue_unsafe: /* * If strict host key checking has not been requested, allow * the connection but without MITM-able authentication or * forwarding. */ if (options.password_authentication) { error("Password authentication is disabled to avoid " "man-in-the-middle attacks."); options.password_authentication = 0; cancelled_forwarding = 1; } if (options.kbd_interactive_authentication) { error("Keyboard-interactive authentication is disabled" " to avoid man-in-the-middle attacks."); options.kbd_interactive_authentication = 0; options.challenge_response_authentication = 0; cancelled_forwarding = 1; } if (options.challenge_response_authentication) { error("Challenge/response authentication is disabled" " to avoid man-in-the-middle attacks."); options.challenge_response_authentication = 0; cancelled_forwarding = 1; } if (options.forward_agent) { error("Agent forwarding is disabled to avoid " "man-in-the-middle attacks."); options.forward_agent = 0; cancelled_forwarding = 1; } if (options.forward_x11) { error("X11 forwarding is disabled to avoid " "man-in-the-middle attacks."); options.forward_x11 = 0; cancelled_forwarding = 1; } if (options.num_local_forwards > 0 || options.num_remote_forwards > 0) { error("Port forwarding is disabled to avoid " "man-in-the-middle attacks."); options.num_local_forwards = options.num_remote_forwards = 0; cancelled_forwarding = 1; } if (options.tun_open != SSH_TUNMODE_NO) { error("Tunnel forwarding is disabled to avoid " "man-in-the-middle attacks."); options.tun_open = SSH_TUNMODE_NO; cancelled_forwarding = 1; } if (options.exit_on_forward_failure && cancelled_forwarding) fatal("Error: forwarding disabled due to host key " "check failure"); /* * XXX Should permit the user to change to use the new id. * This could be done by converting the host key to an * identifying sentence, tell that the host identifies itself * by that sentence, and ask the user if he/she wishes to * accept the authentication. */ break; case HOST_FOUND: fatal("internal error"); break; } if (options.check_host_ip && host_status != HOST_CHANGED && ip_status == HOST_CHANGED) { snprintf(msg, sizeof(msg), "Warning: the %s host key for '%.200s' " "differs from the key for the IP address '%.128s'" "\nOffending key for IP in %s:%lu", type, host, ip, ip_found->file, ip_found->line); if (host_status == HOST_OK) { len = strlen(msg); snprintf(msg + len, sizeof(msg) - len, "\nMatching host key in %s:%lu", host_found->file, host_found->line); } if (options.strict_host_key_checking == SSH_STRICT_HOSTKEY_ASK) { strlcat(msg, "\nAre you sure you want " "to continue connecting (yes/no)? ", sizeof(msg)); if (!confirm(msg)) goto fail; } else if (options.strict_host_key_checking != SSH_STRICT_HOSTKEY_OFF) { logit("%s", msg); error("Exiting, you have requested strict checking."); goto fail; } else { logit("%s", msg); } } if (!hostkey_trusted && options.update_hostkeys) { debug("%s: hostkey not known or explicitly trusted: " "disabling UpdateHostkeys", __func__); options.update_hostkeys = 0; } free(ip); free(host); if (host_hostkeys != NULL) free_hostkeys(host_hostkeys); if (ip_hostkeys != NULL) free_hostkeys(ip_hostkeys); return 0; fail: if (want_cert && host_status != HOST_REVOKED) { /* * No matching certificate. Downgrade cert to raw key and * search normally. */ debug("No matching CA found. Retry with plain key"); if ((r = sshkey_from_private(host_key, &raw_key)) != 0) fatal("%s: sshkey_from_private: %s", __func__, ssh_err(r)); if ((r = sshkey_drop_cert(raw_key)) != 0) fatal("Couldn't drop certificate: %s", ssh_err(r)); host_key = raw_key; goto retry; } sshkey_free(raw_key); free(ip); free(host); if (host_hostkeys != NULL) free_hostkeys(host_hostkeys); if (ip_hostkeys != NULL) free_hostkeys(ip_hostkeys); return -1; } /* returns 0 if key verifies or -1 if key does NOT verify */ int verify_host_key(char *host, struct sockaddr *hostaddr, struct sshkey *host_key) { u_int i; int r = -1, flags = 0; char valid[64], *fp = NULL, *cafp = NULL; struct sshkey *plain = NULL; if ((fp = sshkey_fingerprint(host_key, options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) { error("%s: fingerprint host key: %s", __func__, ssh_err(r)); r = -1; goto out; } if (sshkey_is_cert(host_key)) { if ((cafp = sshkey_fingerprint(host_key->cert->signature_key, options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) { error("%s: fingerprint CA key: %s", __func__, ssh_err(r)); r = -1; goto out; } sshkey_format_cert_validity(host_key->cert, valid, sizeof(valid)); debug("Server host certificate: %s %s, serial %llu " "ID \"%s\" CA %s %s valid %s", sshkey_ssh_name(host_key), fp, (unsigned long long)host_key->cert->serial, host_key->cert->key_id, sshkey_ssh_name(host_key->cert->signature_key), cafp, valid); for (i = 0; i < host_key->cert->nprincipals; i++) { debug2("Server host certificate hostname: %s", host_key->cert->principals[i]); } } else { debug("Server host key: %s %s", sshkey_ssh_name(host_key), fp); } if (sshkey_equal(previous_host_key, host_key)) { debug2("%s: server host key %s %s matches cached key", __func__, sshkey_type(host_key), fp); r = 0; goto out; } /* Check in RevokedHostKeys file if specified */ if (options.revoked_host_keys != NULL) { r = sshkey_check_revoked(host_key, options.revoked_host_keys); switch (r) { case 0: break; /* not revoked */ case SSH_ERR_KEY_REVOKED: error("Host key %s %s revoked by file %s", sshkey_type(host_key), fp, options.revoked_host_keys); r = -1; goto out; default: error("Error checking host key %s %s in " "revoked keys file %s: %s", sshkey_type(host_key), fp, options.revoked_host_keys, ssh_err(r)); r = -1; goto out; } } if (options.verify_host_key_dns) { /* * XXX certs are not yet supported for DNS, so downgrade * them and try the plain key. */ if ((r = sshkey_from_private(host_key, &plain)) != 0) goto out; if (sshkey_is_cert(plain)) sshkey_drop_cert(plain); if (verify_host_key_dns(host, hostaddr, plain, &flags) == 0) { if (flags & DNS_VERIFY_FOUND) { if (options.verify_host_key_dns == 1 && flags & DNS_VERIFY_MATCH && flags & DNS_VERIFY_SECURE) { r = 0; goto out; } if (flags & DNS_VERIFY_MATCH) { matching_host_key_dns = 1; } else { warn_changed_key(plain); error("Update the SSHFP RR in DNS " "with the new host key to get rid " "of this message."); } } } } r = check_host_key(host, hostaddr, options.port, host_key, RDRW, options.user_hostfiles, options.num_user_hostfiles, options.system_hostfiles, options.num_system_hostfiles); out: sshkey_free(plain); free(fp); free(cafp); if (r == 0 && host_key != NULL) { sshkey_free(previous_host_key); r = sshkey_from_private(host_key, &previous_host_key); } return r; } /* * Starts a dialog with the server, and authenticates the current user on the * server. This does not need any extra privileges. The basic connection * to the server must already have been established before this is called. * If login fails, this function prints an error and never returns. * This function does not require super-user privileges. */ void ssh_login(Sensitive *sensitive, const char *orighost, struct sockaddr *hostaddr, u_short port, struct passwd *pw, int timeout_ms) { char *host; char *server_user, *local_user; local_user = xstrdup(pw->pw_name); server_user = options.user ? options.user : local_user; /* Convert the user-supplied hostname into all lowercase. */ host = xstrdup(orighost); lowercase(host); /* Exchange protocol version identification strings with the server. */ ssh_exchange_identification(timeout_ms); /* Put the connection into non-blocking mode. */ packet_set_nonblocking(); /* key exchange */ /* authenticate user */ debug("Authenticating to %s:%d as '%s'", host, port, server_user); ssh_kex2(host, hostaddr, port); ssh_userauth2(local_user, server_user, host, sensitive); free(local_user); } void ssh_put_password(char *password) { int size; char *padded; if (datafellows & SSH_BUG_PASSWORDPAD) { packet_put_cstring(password); return; } size = ROUNDUP(strlen(password) + 1, 32); padded = xcalloc(1, size); strlcpy(padded, password, size); packet_put_string(padded, size); explicit_bzero(padded, size); free(padded); } /* print all known host keys for a given host, but skip keys of given type */ static int show_other_keys(struct hostkeys *hostkeys, struct sshkey *key) { int type[] = { KEY_RSA, KEY_DSA, KEY_ECDSA, KEY_ED25519, KEY_XMSS, -1 }; int i, ret = 0; char *fp, *ra; const struct hostkey_entry *found; for (i = 0; type[i] != -1; i++) { if (type[i] == key->type) continue; if (!lookup_key_in_hostkeys_by_type(hostkeys, type[i], &found)) continue; fp = sshkey_fingerprint(found->key, options.fingerprint_hash, SSH_FP_DEFAULT); ra = sshkey_fingerprint(found->key, options.fingerprint_hash, SSH_FP_RANDOMART); if (fp == NULL || ra == NULL) fatal("%s: sshkey_fingerprint fail", __func__); logit("WARNING: %s key found for host %s\n" "in %s:%lu\n" "%s key fingerprint %s.", sshkey_type(found->key), found->host, found->file, found->line, sshkey_type(found->key), fp); if (options.visual_host_key) logit("%s", ra); free(ra); free(fp); ret = 1; } return ret; } static void warn_changed_key(struct sshkey *host_key) { char *fp; fp = sshkey_fingerprint(host_key, options.fingerprint_hash, SSH_FP_DEFAULT); if (fp == NULL) fatal("%s: sshkey_fingerprint fail", __func__); error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @"); error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!"); error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!"); error("It is also possible that a host key has just been changed."); error("The fingerprint for the %s key sent by the remote host is\n%s.", sshkey_type(host_key), fp); error("Please contact your system administrator."); free(fp); } /* * Execute a local command */ int ssh_local_cmd(const char *args) { char *shell; pid_t pid; int status; void (*osighand)(int); if (!options.permit_local_command || args == NULL || !*args) return (1); if ((shell = getenv("SHELL")) == NULL || *shell == '\0') shell = _PATH_BSHELL; osighand = signal(SIGCHLD, SIG_DFL); pid = fork(); if (pid == 0) { signal(SIGPIPE, SIG_DFL); debug3("Executing %s -c \"%s\"", shell, args); execl(shell, shell, "-c", args, (char *)NULL); error("Couldn't execute %s -c \"%s\": %s", shell, args, strerror(errno)); _exit(1); } else if (pid == -1) fatal("fork failed: %.100s", strerror(errno)); while (waitpid(pid, &status, 0) == -1) if (errno != EINTR) fatal("Couldn't wait for child: %s", strerror(errno)); signal(SIGCHLD, osighand); if (!WIFEXITED(status)) return (1); return (WEXITSTATUS(status)); } void maybe_add_key_to_agent(char *authfile, const struct sshkey *private, char *comment, char *passphrase) { int auth_sock = -1, r; if (options.add_keys_to_agent == 0) return; if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) { debug3("no authentication agent, not adding key"); return; } if (options.add_keys_to_agent == 2 && !ask_permission("Add key %s (%s) to agent?", authfile, comment)) { debug3("user denied adding this key"); close(auth_sock); return; } if ((r = ssh_add_identity_constrained(auth_sock, private, comment, 0, (options.add_keys_to_agent == 3), 0)) == 0) debug("identity added to agent: %s", authfile); else debug("could not add identity to agent: %s (%d)", authfile, r); close(auth_sock); }