diff --git a/crypto/openssh/FREEBSD-upgrade b/crypto/openssh/FREEBSD-upgrade index c8603577a2a2..17161df93316 100644 --- a/crypto/openssh/FREEBSD-upgrade +++ b/crypto/openssh/FREEBSD-upgrade @@ -1,187 +1,186 @@ FreeBSD maintainer's guide to OpenSSH-portable ============================================== These instructions assume you have a clone of the FreeBSD git repo main branch in src/freebsd/main, and will store vendor trees under src/freebsd/vendor/. In addition, this assumes there is a "freebsd" origin pointing to git(repo).freebsd.org/src.git. 01) Make sure your mail spool has plenty of free space. It'll fill up pretty fast once you're done with this checklist. 02) Download the latest OpenSSH-portable tarball and signature from OpenBSD (https://ftp.openbsd.org/pub/OpenBSD/OpenSSH/portable/). 03) Verify the signature: $ gpg --verify openssh-X.YpZ.tar.gz.asc 04) Unpack the tarball in a suitable directory: $ tar xf openssh-X.YpZ.tar.gz 05) Copy to a vendor branch: $ cd src/freebsd/main $ git worktree add ../vendor/openssh freebsd/vendor/openssh $ cd ../vendor/openssh $ rsync --archive --delete --exclude=.git /path/to/openssh-X.YpZ/ ./ 06) Take care of added / deleted files: $ git add -A 07) Commit: $ git commit -m "Vendor import of OpenSSH X.YpZ" 08) Tag: $ git tag -a -m "Tag OpenSSH X.YpZ" vendor/openssh/X.YpZ At this point the vendor branch can be pushed to the FreeBSD repo via: $ git push freebsd vendor/openssh $ git push freebsd vendor/openssh/X.YpZ Note the second "git push" command is used to push the tag, which is not pushed by default. It is also possible to push the branch and tag together, but use --dry-run first to ensure that no undesired tags will be pushed: $ git push --dry-run --follow-tags freebsd vendor/openssh $ git push --follow-tags freebsd vendor/openssh The update and tag could instead be pushed later, along with the merge to main, but pushing now allows others to collaborate. 09) Merge from the vendor branch: $ git subtree merge -P crypto/openssh vendor/openssh A number of files have been deleted from FreeBSD's copy of ssh, including rendered man pages (which have a .0 extension). When git prompts for these deleted files during the merge, choose 'd' (leaving them deleted). 10) Resolve conflicts. Remember to bump the version addendum in version.h, and update the default value in ssh{,d}_config and ssh{,d}_config.5. 11) Diff against the vendor branch: $ git diff --diff-filter=M vendor/openssh/X.YpZ HEAD:crypto/openssh Review the diff for any unexpected changes. 12) Run the configure script: $ sh freebsd-configure.sh 13) Review changes to config.h very carefully. Note that libwrap should not be defined in config.h; as of r311585 (233932cc2a60) it is conditional on MK_TCP_WRAPPERS. 14) If source files have been added or removed, update the appropriate makefiles to reflect changes in the vendor's Makefile.in. 15) Update ssh_namespace.h: $ sh freebsd-namespace.sh 16) Build and install world, reboot, test. Pay particular attention to pam_ssh(8), which gropes inside libssh and will break if something significant changes or if ssh_namespace.h is out of whack. 17) Check for references to obsolete configuration options (e.g., ChallengeResponseAuthentication in sshd_config) which may exist in release/ scripts. 18) Commit, and hunker down for the inevitable storm of complaints. An overview of FreeBSD changes to OpenSSH-portable ================================================== 0) VersionAddendum The SSH protocol allows for a human-readable version string of up to 40 characters to be appended to the protocol version string. FreeBSD takes advantage of this to include a date indicating the "patch level", so people can easily determine whether their system is vulnerable when an OpenSSH advisory goes out. Some people, however, dislike advertising their patch level in the protocol handshake, so we've added a VersionAddendum configuration variable to allow them to change or disable it. Upstream added support for VersionAddendum on the server side, but we also support it on the client side. 1) Modified server-side defaults We've modified some configuration defaults in sshd: - UsePAM defaults to "yes". - PermitRootLogin defaults to "no". - X11Forwarding defaults to "yes". - PasswordAuthentication defaults to "no". - VersionAddendum defaults to "FreeBSD-YYYYMMDD". - UseDNS defaults to "yes". 2) Modified client-side defaults We've modified some configuration defaults in ssh: - CheckHostIP defaults to "no". - - VerifyHostKeyDNS defaults to "yes" if built with LDNS. - VersionAddendum defaults to "FreeBSD-YYYYMMDD". 3) Canonic host names We've added code to ssh.c to canonicize the target host name after reading options but before trying to connect. This eliminates the usual problem with duplicate known_hosts entries. 4) setusercontext() environment Our setusercontext(3) can set environment variables, which we must take care to transfer to the child's environment. 5) TCP wrappers Support for TCP wrappers was removed in upstream 6.7p1. We've added it back by porting the 6.6p1 code forward. TCP wrappers support in sshd will be disabled in HEAD and will be removed from FreeBSD in the future. 6) Agent client reference counting We've added code to ssh-agent.c to implement client reference counting; the agent will automatically exit when the last client disconnects. 7) Class-based login restrictions (27ceebbc2402) We've added code to auth.c to enforce the host.allow, host.deny, times.allow and times.deny login class capabilities, based on an upstream submission from https://github.com/openssh/openssh-portable/pull/262. 8) HPN We no longer have the HPN patches (adaptive buffer size for increased throughput on high-BxD links), but we recognize and ignore HPN-related configuration options to avoid breaking existing configurations. This port was brought to you by (in no particular order) DARPA, NAI Labs, ThinkSec, Nescafé, the Aberlour Glenlivet Distillery Co., Suzanne Vega, and a Sanford's #69 Deluxe Marker. -- des@FreeBSD.org diff --git a/crypto/openssh/readconf.c b/crypto/openssh/readconf.c index 3440d05e4e3b..52c9c47c6879 100644 --- a/crypto/openssh/readconf.c +++ b/crypto/openssh/readconf.c @@ -1,3521 +1,3515 @@ /* $OpenBSD: readconf.c,v 1.372 2023/01/13 02:58:20 dtucker Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland * All rights reserved * Functions for reading the configuration files. * * 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" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef HAVE_PATHS_H # include #endif #include #include #include #include #include #include #ifdef USE_SYSTEM_GLOB # include #else # include "openbsd-compat/glob.h" #endif #ifdef HAVE_UTIL_H #include #endif #if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) && !defined(BROKEN_STRNVIS) # include #endif #include "xmalloc.h" #include "ssh.h" #include "ssherr.h" #include "compat.h" #include "cipher.h" #include "pathnames.h" #include "log.h" #include "sshkey.h" #include "misc.h" #include "readconf.h" #include "match.h" #include "kex.h" #include "mac.h" #include "uidswap.h" #include "myproposal.h" #include "digest.h" #include "version.h" /* Format of the configuration file: # Configuration data is parsed as follows: # 1. command line options # 2. user-specific file # 3. system-wide file # Any configuration value is only changed the first time it is set. # Thus, host-specific definitions should be at the beginning of the # configuration file, and defaults at the end. # Host-specific declarations. These may override anything above. A single # host may match multiple declarations; these are processed in the order # that they are given in. Host *.ngs.fi ngs.fi User foo Host fake.com Hostname another.host.name.real.org User blaah Port 34289 ForwardX11 no ForwardAgent no Host books.com RemoteForward 9999 shadows.cs.hut.fi:9999 Ciphers 3des-cbc Host fascist.blob.com Port 23123 User tylonen PasswordAuthentication no Host puukko.hut.fi User t35124p ProxyCommand ssh-proxy %h %p Host *.fr PublicKeyAuthentication no Host *.su Ciphers aes128-ctr PasswordAuthentication no Host vpn.fake.com Tunnel yes TunnelDevice 3 # Defaults for various options Host * ForwardAgent no ForwardX11 no PasswordAuthentication yes StrictHostKeyChecking yes TcpKeepAlive no IdentityFile ~/.ssh/identity Port 22 EscapeChar ~ */ static int read_config_file_depth(const char *filename, struct passwd *pw, const char *host, const char *original_host, Options *options, int flags, int *activep, int *want_final_pass, int depth); static int process_config_line_depth(Options *options, struct passwd *pw, const char *host, const char *original_host, char *line, const char *filename, int linenum, int *activep, int flags, int *want_final_pass, int depth); /* Keyword tokens. */ typedef enum { oBadOption, oVersionAddendum, oHost, oMatch, oInclude, oForwardAgent, oForwardX11, oForwardX11Trusted, oForwardX11Timeout, oGatewayPorts, oExitOnForwardFailure, oPasswordAuthentication, oXAuthLocation, oIdentityFile, oHostname, oPort, oRemoteForward, oLocalForward, oPermitRemoteOpen, oCertificateFile, oAddKeysToAgent, oIdentityAgent, oUser, oEscapeChar, oProxyCommand, oGlobalKnownHostsFile, oUserKnownHostsFile, oConnectionAttempts, oBatchMode, oCheckHostIP, oStrictHostKeyChecking, oCompression, oTCPKeepAlive, oNumberOfPasswordPrompts, oLogFacility, oLogLevel, oLogVerbose, oCiphers, oMacs, oPubkeyAuthentication, oKbdInteractiveAuthentication, oKbdInteractiveDevices, oHostKeyAlias, oDynamicForward, oPreferredAuthentications, oHostbasedAuthentication, oHostKeyAlgorithms, oBindAddress, oBindInterface, oPKCS11Provider, oClearAllForwardings, oNoHostAuthenticationForLocalhost, oEnableSSHKeysign, oRekeyLimit, oVerifyHostKeyDNS, oConnectTimeout, oAddressFamily, oGssAuthentication, oGssDelegateCreds, oServerAliveInterval, oServerAliveCountMax, oIdentitiesOnly, oSendEnv, oSetEnv, oControlPath, oControlMaster, oControlPersist, oHashKnownHosts, oTunnel, oTunnelDevice, oLocalCommand, oPermitLocalCommand, oRemoteCommand, oVisualHostKey, oKexAlgorithms, oIPQoS, oRequestTTY, oSessionType, oStdinNull, oForkAfterAuthentication, oIgnoreUnknown, oProxyUseFdpass, oCanonicalDomains, oCanonicalizeHostname, oCanonicalizeMaxDots, oCanonicalizeFallbackLocal, oCanonicalizePermittedCNAMEs, oStreamLocalBindMask, oStreamLocalBindUnlink, oRevokedHostKeys, oFingerprintHash, oUpdateHostkeys, oHostbasedAcceptedAlgorithms, oPubkeyAcceptedAlgorithms, oCASignatureAlgorithms, oProxyJump, oSecurityKeyProvider, oKnownHostsCommand, oRequiredRSASize, oEnableEscapeCommandline, oIgnore, oIgnoredUnknownOption, oDeprecated, oUnsupported } OpCodes; /* Textual representations of the tokens. */ static struct { const char *name; OpCodes opcode; } keywords[] = { /* Deprecated options */ { "protocol", oIgnore }, /* NB. silently ignored */ { "cipher", oDeprecated }, { "fallbacktorsh", oDeprecated }, { "globalknownhostsfile2", oDeprecated }, { "rhostsauthentication", oDeprecated }, { "userknownhostsfile2", oDeprecated }, { "useroaming", oDeprecated }, { "usersh", oDeprecated }, { "useprivilegedport", oDeprecated }, /* Unsupported options */ { "afstokenpassing", oUnsupported }, { "kerberosauthentication", oUnsupported }, { "kerberostgtpassing", oUnsupported }, { "rsaauthentication", oUnsupported }, { "rhostsrsaauthentication", oUnsupported }, { "compressionlevel", oUnsupported }, /* Sometimes-unsupported options */ #if defined(GSSAPI) { "gssapiauthentication", oGssAuthentication }, { "gssapidelegatecredentials", oGssDelegateCreds }, # else { "gssapiauthentication", oUnsupported }, { "gssapidelegatecredentials", oUnsupported }, #endif #ifdef ENABLE_PKCS11 { "pkcs11provider", oPKCS11Provider }, { "smartcarddevice", oPKCS11Provider }, # else { "smartcarddevice", oUnsupported }, { "pkcs11provider", oUnsupported }, #endif { "forwardagent", oForwardAgent }, { "forwardx11", oForwardX11 }, { "forwardx11trusted", oForwardX11Trusted }, { "forwardx11timeout", oForwardX11Timeout }, { "exitonforwardfailure", oExitOnForwardFailure }, { "xauthlocation", oXAuthLocation }, { "gatewayports", oGatewayPorts }, { "passwordauthentication", oPasswordAuthentication }, { "kbdinteractiveauthentication", oKbdInteractiveAuthentication }, { "kbdinteractivedevices", oKbdInteractiveDevices }, { "challengeresponseauthentication", oKbdInteractiveAuthentication }, /* alias */ { "skeyauthentication", oKbdInteractiveAuthentication }, /* alias */ { "tisauthentication", oKbdInteractiveAuthentication }, /* alias */ { "pubkeyauthentication", oPubkeyAuthentication }, { "dsaauthentication", oPubkeyAuthentication }, /* alias */ { "hostbasedauthentication", oHostbasedAuthentication }, { "identityfile", oIdentityFile }, { "identityfile2", oIdentityFile }, /* obsolete */ { "identitiesonly", oIdentitiesOnly }, { "certificatefile", oCertificateFile }, { "addkeystoagent", oAddKeysToAgent }, { "identityagent", oIdentityAgent }, { "hostname", oHostname }, { "hostkeyalias", oHostKeyAlias }, { "proxycommand", oProxyCommand }, { "port", oPort }, { "ciphers", oCiphers }, { "macs", oMacs }, { "remoteforward", oRemoteForward }, { "localforward", oLocalForward }, { "permitremoteopen", oPermitRemoteOpen }, { "user", oUser }, { "host", oHost }, { "match", oMatch }, { "escapechar", oEscapeChar }, { "globalknownhostsfile", oGlobalKnownHostsFile }, { "userknownhostsfile", oUserKnownHostsFile }, { "connectionattempts", oConnectionAttempts }, { "batchmode", oBatchMode }, { "checkhostip", oCheckHostIP }, { "stricthostkeychecking", oStrictHostKeyChecking }, { "compression", oCompression }, { "tcpkeepalive", oTCPKeepAlive }, { "keepalive", oTCPKeepAlive }, /* obsolete */ { "numberofpasswordprompts", oNumberOfPasswordPrompts }, { "syslogfacility", oLogFacility }, { "loglevel", oLogLevel }, { "logverbose", oLogVerbose }, { "dynamicforward", oDynamicForward }, { "preferredauthentications", oPreferredAuthentications }, { "hostkeyalgorithms", oHostKeyAlgorithms }, { "casignaturealgorithms", oCASignatureAlgorithms }, { "bindaddress", oBindAddress }, { "bindinterface", oBindInterface }, { "clearallforwardings", oClearAllForwardings }, { "enablesshkeysign", oEnableSSHKeysign }, { "verifyhostkeydns", oVerifyHostKeyDNS }, { "nohostauthenticationforlocalhost", oNoHostAuthenticationForLocalhost }, { "rekeylimit", oRekeyLimit }, { "connecttimeout", oConnectTimeout }, { "addressfamily", oAddressFamily }, { "serveraliveinterval", oServerAliveInterval }, { "serveralivecountmax", oServerAliveCountMax }, { "sendenv", oSendEnv }, { "setenv", oSetEnv }, { "controlpath", oControlPath }, { "controlmaster", oControlMaster }, { "controlpersist", oControlPersist }, { "hashknownhosts", oHashKnownHosts }, { "include", oInclude }, { "tunnel", oTunnel }, { "tunneldevice", oTunnelDevice }, { "localcommand", oLocalCommand }, { "permitlocalcommand", oPermitLocalCommand }, { "remotecommand", oRemoteCommand }, { "visualhostkey", oVisualHostKey }, { "kexalgorithms", oKexAlgorithms }, { "ipqos", oIPQoS }, { "requesttty", oRequestTTY }, { "sessiontype", oSessionType }, { "stdinnull", oStdinNull }, { "forkafterauthentication", oForkAfterAuthentication }, { "proxyusefdpass", oProxyUseFdpass }, { "canonicaldomains", oCanonicalDomains }, { "canonicalizefallbacklocal", oCanonicalizeFallbackLocal }, { "canonicalizehostname", oCanonicalizeHostname }, { "canonicalizemaxdots", oCanonicalizeMaxDots }, { "canonicalizepermittedcnames", oCanonicalizePermittedCNAMEs }, { "streamlocalbindmask", oStreamLocalBindMask }, { "streamlocalbindunlink", oStreamLocalBindUnlink }, { "revokedhostkeys", oRevokedHostKeys }, { "fingerprinthash", oFingerprintHash }, { "updatehostkeys", oUpdateHostkeys }, { "hostbasedacceptedalgorithms", oHostbasedAcceptedAlgorithms }, { "hostbasedkeytypes", oHostbasedAcceptedAlgorithms }, /* obsolete */ { "pubkeyacceptedalgorithms", oPubkeyAcceptedAlgorithms }, { "pubkeyacceptedkeytypes", oPubkeyAcceptedAlgorithms }, /* obsolete */ { "ignoreunknown", oIgnoreUnknown }, { "proxyjump", oProxyJump }, { "securitykeyprovider", oSecurityKeyProvider }, { "knownhostscommand", oKnownHostsCommand }, { "requiredrsasize", oRequiredRSASize }, { "enableescapecommandline", oEnableEscapeCommandline }, { "hpndisabled", oDeprecated }, { "hpnbuffersize", oDeprecated }, { "tcprcvbufpoll", oDeprecated }, { "tcprcvbuf", oDeprecated }, { "noneenabled", oUnsupported }, { "noneswitch", oUnsupported }, { "versionaddendum", oVersionAddendum }, { NULL, oBadOption } }; static const char *lookup_opcode_name(OpCodes code); const char * kex_default_pk_alg(void) { static char *pkalgs; if (pkalgs == NULL) { char *all_key; all_key = sshkey_alg_list(0, 0, 1, ','); pkalgs = match_filter_allowlist(KEX_DEFAULT_PK_ALG, all_key); free(all_key); } return pkalgs; } char * ssh_connection_hash(const char *thishost, const char *host, const char *portstr, const char *user) { struct ssh_digest_ctx *md; u_char conn_hash[SSH_DIGEST_MAX_LENGTH]; if ((md = ssh_digest_start(SSH_DIGEST_SHA1)) == NULL || ssh_digest_update(md, thishost, strlen(thishost)) < 0 || ssh_digest_update(md, host, strlen(host)) < 0 || ssh_digest_update(md, portstr, strlen(portstr)) < 0 || ssh_digest_update(md, user, strlen(user)) < 0 || ssh_digest_final(md, conn_hash, sizeof(conn_hash)) < 0) fatal_f("mux digest failed"); ssh_digest_free(md); return tohex(conn_hash, ssh_digest_bytes(SSH_DIGEST_SHA1)); } /* * Adds a local TCP/IP port forward to options. Never returns if there is an * error. */ void add_local_forward(Options *options, const struct Forward *newfwd) { struct Forward *fwd; int i; /* Don't add duplicates */ for (i = 0; i < options->num_local_forwards; i++) { if (forward_equals(newfwd, options->local_forwards + i)) return; } options->local_forwards = xreallocarray(options->local_forwards, options->num_local_forwards + 1, sizeof(*options->local_forwards)); fwd = &options->local_forwards[options->num_local_forwards++]; fwd->listen_host = newfwd->listen_host; fwd->listen_port = newfwd->listen_port; fwd->listen_path = newfwd->listen_path; fwd->connect_host = newfwd->connect_host; fwd->connect_port = newfwd->connect_port; fwd->connect_path = newfwd->connect_path; } /* * Adds a remote TCP/IP port forward to options. Never returns if there is * an error. */ void add_remote_forward(Options *options, const struct Forward *newfwd) { struct Forward *fwd; int i; /* Don't add duplicates */ for (i = 0; i < options->num_remote_forwards; i++) { if (forward_equals(newfwd, options->remote_forwards + i)) return; } options->remote_forwards = xreallocarray(options->remote_forwards, options->num_remote_forwards + 1, sizeof(*options->remote_forwards)); fwd = &options->remote_forwards[options->num_remote_forwards++]; fwd->listen_host = newfwd->listen_host; fwd->listen_port = newfwd->listen_port; fwd->listen_path = newfwd->listen_path; fwd->connect_host = newfwd->connect_host; fwd->connect_port = newfwd->connect_port; fwd->connect_path = newfwd->connect_path; fwd->handle = newfwd->handle; fwd->allocated_port = 0; } static void clear_forwardings(Options *options) { int i; for (i = 0; i < options->num_local_forwards; i++) { free(options->local_forwards[i].listen_host); free(options->local_forwards[i].listen_path); free(options->local_forwards[i].connect_host); free(options->local_forwards[i].connect_path); } if (options->num_local_forwards > 0) { free(options->local_forwards); options->local_forwards = NULL; } options->num_local_forwards = 0; for (i = 0; i < options->num_remote_forwards; i++) { free(options->remote_forwards[i].listen_host); free(options->remote_forwards[i].listen_path); free(options->remote_forwards[i].connect_host); free(options->remote_forwards[i].connect_path); } if (options->num_remote_forwards > 0) { free(options->remote_forwards); options->remote_forwards = NULL; } options->num_remote_forwards = 0; options->tun_open = SSH_TUNMODE_NO; } void add_certificate_file(Options *options, const char *path, int userprovided) { int i; if (options->num_certificate_files >= SSH_MAX_CERTIFICATE_FILES) fatal("Too many certificate files specified (max %d)", SSH_MAX_CERTIFICATE_FILES); /* Avoid registering duplicates */ for (i = 0; i < options->num_certificate_files; i++) { if (options->certificate_file_userprovided[i] == userprovided && strcmp(options->certificate_files[i], path) == 0) { debug2_f("ignoring duplicate key %s", path); return; } } options->certificate_file_userprovided[options->num_certificate_files] = userprovided; options->certificate_files[options->num_certificate_files++] = xstrdup(path); } void add_identity_file(Options *options, const char *dir, const char *filename, int userprovided) { char *path; int i; if (options->num_identity_files >= SSH_MAX_IDENTITY_FILES) fatal("Too many identity files specified (max %d)", SSH_MAX_IDENTITY_FILES); if (dir == NULL) /* no dir, filename is absolute */ path = xstrdup(filename); else if (xasprintf(&path, "%s%s", dir, filename) >= PATH_MAX) fatal("Identity file path %s too long", path); /* Avoid registering duplicates */ for (i = 0; i < options->num_identity_files; i++) { if (options->identity_file_userprovided[i] == userprovided && strcmp(options->identity_files[i], path) == 0) { debug2_f("ignoring duplicate key %s", path); free(path); return; } } options->identity_file_userprovided[options->num_identity_files] = userprovided; options->identity_files[options->num_identity_files++] = path; } int default_ssh_port(void) { static int port; struct servent *sp; if (port == 0) { sp = getservbyname(SSH_SERVICE_NAME, "tcp"); port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT; } return port; } /* * Execute a command in a shell. * Return its exit status or -1 on abnormal exit. */ static int execute_in_shell(const char *cmd) { char *shell; pid_t pid; int status; if ((shell = getenv("SHELL")) == NULL) shell = _PATH_BSHELL; if (access(shell, X_OK) == -1) { fatal("Shell \"%s\" is not executable: %s", shell, strerror(errno)); } debug("Executing command: '%.500s'", cmd); /* Fork and execute the command. */ if ((pid = fork()) == 0) { char *argv[4]; if (stdfd_devnull(1, 1, 0) == -1) fatal_f("stdfd_devnull failed"); closefrom(STDERR_FILENO + 1); argv[0] = shell; argv[1] = "-c"; argv[2] = xstrdup(cmd); argv[3] = NULL; execv(argv[0], argv); error("Unable to execute '%.100s': %s", cmd, strerror(errno)); /* Die with signal to make this error apparent to parent. */ ssh_signal(SIGTERM, SIG_DFL); kill(getpid(), SIGTERM); _exit(1); } /* Parent. */ if (pid == -1) fatal_f("fork: %.100s", strerror(errno)); while (waitpid(pid, &status, 0) == -1) { if (errno != EINTR && errno != EAGAIN) fatal_f("waitpid: %s", strerror(errno)); } if (!WIFEXITED(status)) { error("command '%.100s' exited abnormally", cmd); return -1; } debug3("command returned status %d", WEXITSTATUS(status)); return WEXITSTATUS(status); } /* * Parse and execute a Match directive. */ static int match_cfg_line(Options *options, char **condition, struct passwd *pw, const char *host_arg, const char *original_host, int final_pass, int *want_final_pass, const char *filename, int linenum) { char *arg, *oattrib, *attrib, *cmd, *cp = *condition, *host, *criteria; const char *ruser; int r, port, this_result, result = 1, attributes = 0, negate; char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV]; char uidstr[32]; /* * Configuration is likely to be incomplete at this point so we * must be prepared to use default values. */ port = options->port <= 0 ? default_ssh_port() : options->port; ruser = options->user == NULL ? pw->pw_name : options->user; if (final_pass) { host = xstrdup(options->hostname); } else if (options->hostname != NULL) { /* NB. Please keep in sync with ssh.c:main() */ host = percent_expand(options->hostname, "h", host_arg, (char *)NULL); } else { host = xstrdup(host_arg); } debug2("checking match for '%s' host %s originally %s", cp, host, original_host); while ((oattrib = attrib = strdelim(&cp)) && *attrib != '\0') { /* Terminate on comment */ if (*attrib == '#') { cp = NULL; /* mark all arguments consumed */ break; } arg = criteria = NULL; this_result = 1; if ((negate = attrib[0] == '!')) attrib++; /* Criterion "all" has no argument and must appear alone */ if (strcasecmp(attrib, "all") == 0) { if (attributes > 1 || ((arg = strdelim(&cp)) != NULL && *arg != '\0' && *arg != '#')) { error("%.200s line %d: '%s' cannot be combined " "with other Match attributes", filename, linenum, oattrib); result = -1; goto out; } if (arg != NULL && *arg == '#') cp = NULL; /* mark all arguments consumed */ if (result) result = negate ? 0 : 1; goto out; } attributes++; /* criteria "final" and "canonical" have no argument */ if (strcasecmp(attrib, "canonical") == 0 || strcasecmp(attrib, "final") == 0) { /* * If the config requests "Match final" then remember * this so we can perform a second pass later. */ if (strcasecmp(attrib, "final") == 0 && want_final_pass != NULL) *want_final_pass = 1; r = !!final_pass; /* force bitmask member to boolean */ if (r == (negate ? 1 : 0)) this_result = result = 0; debug3("%.200s line %d: %smatched '%s'", filename, linenum, this_result ? "" : "not ", oattrib); continue; } /* All other criteria require an argument */ if ((arg = strdelim(&cp)) == NULL || *arg == '\0' || *arg == '#') { error("Missing Match criteria for %s", attrib); result = -1; goto out; } if (strcasecmp(attrib, "host") == 0) { criteria = xstrdup(host); r = match_hostname(host, arg) == 1; if (r == (negate ? 1 : 0)) this_result = result = 0; } else if (strcasecmp(attrib, "originalhost") == 0) { criteria = xstrdup(original_host); r = match_hostname(original_host, arg) == 1; if (r == (negate ? 1 : 0)) this_result = result = 0; } else if (strcasecmp(attrib, "user") == 0) { criteria = xstrdup(ruser); r = match_pattern_list(ruser, arg, 0) == 1; if (r == (negate ? 1 : 0)) this_result = result = 0; } else if (strcasecmp(attrib, "localuser") == 0) { criteria = xstrdup(pw->pw_name); r = match_pattern_list(pw->pw_name, arg, 0) == 1; if (r == (negate ? 1 : 0)) this_result = result = 0; } else if (strcasecmp(attrib, "exec") == 0) { char *conn_hash_hex, *keyalias; if (gethostname(thishost, sizeof(thishost)) == -1) fatal("gethostname: %s", strerror(errno)); strlcpy(shorthost, thishost, sizeof(shorthost)); shorthost[strcspn(thishost, ".")] = '\0'; snprintf(portstr, sizeof(portstr), "%d", port); snprintf(uidstr, sizeof(uidstr), "%llu", (unsigned long long)pw->pw_uid); conn_hash_hex = ssh_connection_hash(thishost, host, portstr, ruser); keyalias = options->host_key_alias ? options->host_key_alias : host; cmd = percent_expand(arg, "C", conn_hash_hex, "L", shorthost, "d", pw->pw_dir, "h", host, "k", keyalias, "l", thishost, "n", original_host, "p", portstr, "r", ruser, "u", pw->pw_name, "i", uidstr, (char *)NULL); free(conn_hash_hex); if (result != 1) { /* skip execution if prior predicate failed */ debug3("%.200s line %d: skipped exec " "\"%.100s\"", filename, linenum, cmd); free(cmd); continue; } r = execute_in_shell(cmd); if (r == -1) { fatal("%.200s line %d: match exec " "'%.100s' error", filename, linenum, cmd); } criteria = xstrdup(cmd); free(cmd); /* Force exit status to boolean */ r = r == 0; if (r == (negate ? 1 : 0)) this_result = result = 0; } else { error("Unsupported Match attribute %s", attrib); result = -1; goto out; } debug3("%.200s line %d: %smatched '%s \"%.100s\"' ", filename, linenum, this_result ? "": "not ", oattrib, criteria); free(criteria); } if (attributes == 0) { error("One or more attributes required for Match"); result = -1; goto out; } out: if (result != -1) debug2("match %sfound", result ? "" : "not "); *condition = cp; free(host); return result; } /* Remove environment variable by pattern */ static void rm_env(Options *options, const char *arg, const char *filename, int linenum) { u_int i, j, onum_send_env = options->num_send_env; /* Remove an environment variable */ for (i = 0; i < options->num_send_env; ) { if (!match_pattern(options->send_env[i], arg + 1)) { i++; continue; } debug3("%s line %d: removing environment %s", filename, linenum, options->send_env[i]); free(options->send_env[i]); options->send_env[i] = NULL; for (j = i; j < options->num_send_env - 1; j++) { options->send_env[j] = options->send_env[j + 1]; options->send_env[j + 1] = NULL; } options->num_send_env--; /* NB. don't increment i */ } if (onum_send_env != options->num_send_env) { options->send_env = xrecallocarray(options->send_env, onum_send_env, options->num_send_env, sizeof(*options->send_env)); } } /* * Returns the number of the token pointed to by cp or oBadOption. */ static OpCodes parse_token(const char *cp, const char *filename, int linenum, const char *ignored_unknown) { int i; for (i = 0; keywords[i].name; i++) if (strcmp(cp, keywords[i].name) == 0) return keywords[i].opcode; if (ignored_unknown != NULL && match_pattern_list(cp, ignored_unknown, 1) == 1) return oIgnoredUnknownOption; error("%s: line %d: Bad configuration option: %s", filename, linenum, cp); return oBadOption; } /* Multistate option parsing */ struct multistate { char *key; int value; }; static const struct multistate multistate_flag[] = { { "true", 1 }, { "false", 0 }, { "yes", 1 }, { "no", 0 }, { NULL, -1 } }; static const struct multistate multistate_yesnoask[] = { { "true", 1 }, { "false", 0 }, { "yes", 1 }, { "no", 0 }, { "ask", 2 }, { NULL, -1 } }; static const struct multistate multistate_strict_hostkey[] = { { "true", SSH_STRICT_HOSTKEY_YES }, { "false", SSH_STRICT_HOSTKEY_OFF }, { "yes", SSH_STRICT_HOSTKEY_YES }, { "no", SSH_STRICT_HOSTKEY_OFF }, { "ask", SSH_STRICT_HOSTKEY_ASK }, { "off", SSH_STRICT_HOSTKEY_OFF }, { "accept-new", SSH_STRICT_HOSTKEY_NEW }, { NULL, -1 } }; static const struct multistate multistate_yesnoaskconfirm[] = { { "true", 1 }, { "false", 0 }, { "yes", 1 }, { "no", 0 }, { "ask", 2 }, { "confirm", 3 }, { NULL, -1 } }; static const struct multistate multistate_addressfamily[] = { { "inet", AF_INET }, { "inet6", AF_INET6 }, { "any", AF_UNSPEC }, { NULL, -1 } }; static const struct multistate multistate_controlmaster[] = { { "true", SSHCTL_MASTER_YES }, { "yes", SSHCTL_MASTER_YES }, { "false", SSHCTL_MASTER_NO }, { "no", SSHCTL_MASTER_NO }, { "auto", SSHCTL_MASTER_AUTO }, { "ask", SSHCTL_MASTER_ASK }, { "autoask", SSHCTL_MASTER_AUTO_ASK }, { NULL, -1 } }; static const struct multistate multistate_tunnel[] = { { "ethernet", SSH_TUNMODE_ETHERNET }, { "point-to-point", SSH_TUNMODE_POINTOPOINT }, { "true", SSH_TUNMODE_DEFAULT }, { "yes", SSH_TUNMODE_DEFAULT }, { "false", SSH_TUNMODE_NO }, { "no", SSH_TUNMODE_NO }, { NULL, -1 } }; static const struct multistate multistate_requesttty[] = { { "true", REQUEST_TTY_YES }, { "yes", REQUEST_TTY_YES }, { "false", REQUEST_TTY_NO }, { "no", REQUEST_TTY_NO }, { "force", REQUEST_TTY_FORCE }, { "auto", REQUEST_TTY_AUTO }, { NULL, -1 } }; static const struct multistate multistate_sessiontype[] = { { "none", SESSION_TYPE_NONE }, { "subsystem", SESSION_TYPE_SUBSYSTEM }, { "default", SESSION_TYPE_DEFAULT }, { NULL, -1 } }; static const struct multistate multistate_canonicalizehostname[] = { { "true", SSH_CANONICALISE_YES }, { "false", SSH_CANONICALISE_NO }, { "yes", SSH_CANONICALISE_YES }, { "no", SSH_CANONICALISE_NO }, { "always", SSH_CANONICALISE_ALWAYS }, { NULL, -1 } }; static const struct multistate multistate_pubkey_auth[] = { { "true", SSH_PUBKEY_AUTH_ALL }, { "false", SSH_PUBKEY_AUTH_NO }, { "yes", SSH_PUBKEY_AUTH_ALL }, { "no", SSH_PUBKEY_AUTH_NO }, { "unbound", SSH_PUBKEY_AUTH_UNBOUND }, { "host-bound", SSH_PUBKEY_AUTH_HBOUND }, { NULL, -1 } }; static const struct multistate multistate_compression[] = { #ifdef WITH_ZLIB { "yes", COMP_ZLIB }, #endif { "no", COMP_NONE }, { NULL, -1 } }; static int parse_multistate_value(const char *arg, const char *filename, int linenum, const struct multistate *multistate_ptr) { int i; if (!arg || *arg == '\0') { error("%s line %d: missing argument.", filename, linenum); return -1; } for (i = 0; multistate_ptr[i].key != NULL; i++) { if (strcasecmp(arg, multistate_ptr[i].key) == 0) return multistate_ptr[i].value; } return -1; } /* * Processes a single option line as used in the configuration files. This * only sets those values that have not already been set. */ int process_config_line(Options *options, struct passwd *pw, const char *host, const char *original_host, char *line, const char *filename, int linenum, int *activep, int flags) { return process_config_line_depth(options, pw, host, original_host, line, filename, linenum, activep, flags, NULL, 0); } #define WHITESPACE " \t\r\n" static int process_config_line_depth(Options *options, struct passwd *pw, const char *host, const char *original_host, char *line, const char *filename, int linenum, int *activep, int flags, int *want_final_pass, int depth) { char *str, **charptr, *endofnumber, *keyword, *arg, *arg2, *p; char **cpptr, ***cppptr, fwdarg[256]; u_int i, *uintptr, uvalue, max_entries = 0; int r, oactive, negated, opcode, *intptr, value, value2, cmdline = 0; int remotefwd, dynamicfwd; LogLevel *log_level_ptr; SyslogFacility *log_facility_ptr; long long val64; size_t len; struct Forward fwd; const struct multistate *multistate_ptr; struct allowed_cname *cname; glob_t gl; const char *errstr; char **oav = NULL, **av; int oac = 0, ac; int ret = -1; if (activep == NULL) { /* We are processing a command line directive */ cmdline = 1; activep = &cmdline; } /* Strip trailing whitespace. Allow \f (form feed) at EOL only */ if ((len = strlen(line)) == 0) return 0; for (len--; len > 0; len--) { if (strchr(WHITESPACE "\f", line[len]) == NULL) break; line[len] = '\0'; } str = line; /* Get the keyword. (Each line is supposed to begin with a keyword). */ if ((keyword = strdelim(&str)) == NULL) return 0; /* Ignore leading whitespace. */ if (*keyword == '\0') keyword = strdelim(&str); if (keyword == NULL || !*keyword || *keyword == '\n' || *keyword == '#') return 0; /* Match lowercase keyword */ lowercase(keyword); /* Prepare to parse remainder of line */ if (str != NULL) str += strspn(str, WHITESPACE); if (str == NULL || *str == '\0') { error("%s line %d: no argument after keyword \"%s\"", filename, linenum, keyword); return -1; } opcode = parse_token(keyword, filename, linenum, options->ignored_unknown); if (argv_split(str, &oac, &oav, 1) != 0) { error("%s line %d: invalid quotes", filename, linenum); return -1; } ac = oac; av = oav; switch (opcode) { case oBadOption: /* don't panic, but count bad options */ goto out; case oIgnore: argv_consume(&ac); break; case oIgnoredUnknownOption: debug("%s line %d: Ignored unknown option \"%s\"", filename, linenum, keyword); argv_consume(&ac); break; case oConnectTimeout: intptr = &options->connection_timeout; parse_time: arg = argv_next(&ac, &av); if (!arg || *arg == '\0') { error("%s line %d: missing time value.", filename, linenum); goto out; } if (strcmp(arg, "none") == 0) value = -1; else if ((value = convtime(arg)) == -1) { error("%s line %d: invalid time value.", filename, linenum); goto out; } if (*activep && *intptr == -1) *intptr = value; break; case oForwardAgent: intptr = &options->forward_agent; arg = argv_next(&ac, &av); if (!arg || *arg == '\0') { error("%s line %d: missing argument.", filename, linenum); goto out; } value = -1; multistate_ptr = multistate_flag; for (i = 0; multistate_ptr[i].key != NULL; i++) { if (strcasecmp(arg, multistate_ptr[i].key) == 0) { value = multistate_ptr[i].value; break; } } if (value != -1) { if (*activep && *intptr == -1) *intptr = value; break; } /* ForwardAgent wasn't 'yes' or 'no', assume a path */ if (*activep && *intptr == -1) *intptr = 1; charptr = &options->forward_agent_sock_path; goto parse_agent_path; case oForwardX11: intptr = &options->forward_x11; parse_flag: multistate_ptr = multistate_flag; parse_multistate: arg = argv_next(&ac, &av); if ((value = parse_multistate_value(arg, filename, linenum, multistate_ptr)) == -1) { error("%s line %d: unsupported option \"%s\".", filename, linenum, arg); goto out; } if (*activep && *intptr == -1) *intptr = value; break; case oForwardX11Trusted: intptr = &options->forward_x11_trusted; goto parse_flag; case oForwardX11Timeout: intptr = &options->forward_x11_timeout; goto parse_time; case oGatewayPorts: intptr = &options->fwd_opts.gateway_ports; goto parse_flag; case oExitOnForwardFailure: intptr = &options->exit_on_forward_failure; goto parse_flag; case oPasswordAuthentication: intptr = &options->password_authentication; goto parse_flag; case oKbdInteractiveAuthentication: intptr = &options->kbd_interactive_authentication; goto parse_flag; case oKbdInteractiveDevices: charptr = &options->kbd_interactive_devices; goto parse_string; case oPubkeyAuthentication: multistate_ptr = multistate_pubkey_auth; intptr = &options->pubkey_authentication; goto parse_multistate; case oHostbasedAuthentication: intptr = &options->hostbased_authentication; goto parse_flag; case oGssAuthentication: intptr = &options->gss_authentication; goto parse_flag; case oGssDelegateCreds: intptr = &options->gss_deleg_creds; goto parse_flag; case oBatchMode: intptr = &options->batch_mode; goto parse_flag; case oCheckHostIP: intptr = &options->check_host_ip; goto parse_flag; case oVerifyHostKeyDNS: intptr = &options->verify_host_key_dns; multistate_ptr = multistate_yesnoask; goto parse_multistate; case oStrictHostKeyChecking: intptr = &options->strict_host_key_checking; multistate_ptr = multistate_strict_hostkey; goto parse_multistate; case oCompression: intptr = &options->compression; multistate_ptr = multistate_compression; goto parse_multistate; case oTCPKeepAlive: intptr = &options->tcp_keep_alive; goto parse_flag; case oNoHostAuthenticationForLocalhost: intptr = &options->no_host_authentication_for_localhost; goto parse_flag; case oNumberOfPasswordPrompts: intptr = &options->number_of_password_prompts; goto parse_int; case oRekeyLimit: arg = argv_next(&ac, &av); if (!arg || *arg == '\0') { error("%.200s line %d: Missing argument.", filename, linenum); goto out; } if (strcmp(arg, "default") == 0) { val64 = 0; } else { if (scan_scaled(arg, &val64) == -1) { error("%.200s line %d: Bad number '%s': %s", filename, linenum, arg, strerror(errno)); goto out; } if (val64 != 0 && val64 < 16) { error("%.200s line %d: RekeyLimit too small", filename, linenum); goto out; } } if (*activep && options->rekey_limit == -1) options->rekey_limit = val64; if (ac != 0) { /* optional rekey interval present */ if (strcmp(av[0], "none") == 0) { (void)argv_next(&ac, &av); /* discard */ break; } intptr = &options->rekey_interval; goto parse_time; } break; case oIdentityFile: arg = argv_next(&ac, &av); if (!arg || *arg == '\0') { error("%.200s line %d: Missing argument.", filename, linenum); goto out; } if (*activep) { intptr = &options->num_identity_files; if (*intptr >= SSH_MAX_IDENTITY_FILES) { error("%.200s line %d: Too many identity files " "specified (max %d).", filename, linenum, SSH_MAX_IDENTITY_FILES); goto out; } add_identity_file(options, NULL, arg, flags & SSHCONF_USERCONF); } break; case oCertificateFile: arg = argv_next(&ac, &av); if (!arg || *arg == '\0') { error("%.200s line %d: Missing argument.", filename, linenum); goto out; } if (*activep) { intptr = &options->num_certificate_files; if (*intptr >= SSH_MAX_CERTIFICATE_FILES) { error("%.200s line %d: Too many certificate " "files specified (max %d).", filename, linenum, SSH_MAX_CERTIFICATE_FILES); goto out; } add_certificate_file(options, arg, flags & SSHCONF_USERCONF); } break; case oXAuthLocation: charptr=&options->xauth_location; goto parse_string; case oUser: charptr = &options->user; parse_string: arg = argv_next(&ac, &av); if (!arg || *arg == '\0') { error("%.200s line %d: Missing argument.", filename, linenum); goto out; } if (*activep && *charptr == NULL) *charptr = xstrdup(arg); break; case oGlobalKnownHostsFile: cpptr = (char **)&options->system_hostfiles; uintptr = &options->num_system_hostfiles; max_entries = SSH_MAX_HOSTS_FILES; parse_char_array: i = 0; value = *uintptr == 0; /* was array empty when we started? */ while ((arg = argv_next(&ac, &av)) != NULL) { if (*arg == '\0') { error("%s line %d: keyword %s empty argument", filename, linenum, keyword); goto out; } /* Allow "none" only in first position */ if (strcasecmp(arg, "none") == 0) { if (i > 0 || ac > 0) { error("%s line %d: keyword %s \"none\" " "argument must appear alone.", filename, linenum, keyword); goto out; } } i++; if (*activep && value) { if ((*uintptr) >= max_entries) { error("%s line %d: too many %s " "entries.", filename, linenum, keyword); goto out; } cpptr[(*uintptr)++] = xstrdup(arg); } } break; case oUserKnownHostsFile: cpptr = (char **)&options->user_hostfiles; uintptr = &options->num_user_hostfiles; max_entries = SSH_MAX_HOSTS_FILES; goto parse_char_array; case oHostname: charptr = &options->hostname; goto parse_string; case oHostKeyAlias: charptr = &options->host_key_alias; goto parse_string; case oPreferredAuthentications: charptr = &options->preferred_authentications; goto parse_string; case oBindAddress: charptr = &options->bind_address; goto parse_string; case oBindInterface: charptr = &options->bind_interface; goto parse_string; case oPKCS11Provider: charptr = &options->pkcs11_provider; goto parse_string; case oSecurityKeyProvider: charptr = &options->sk_provider; goto parse_string; case oKnownHostsCommand: charptr = &options->known_hosts_command; goto parse_command; case oProxyCommand: charptr = &options->proxy_command; /* Ignore ProxyCommand if ProxyJump already specified */ if (options->jump_host != NULL) charptr = &options->jump_host; /* Skip below */ parse_command: if (str == NULL) { error("%.200s line %d: Missing argument.", filename, linenum); goto out; } len = strspn(str, WHITESPACE "="); if (*activep && *charptr == NULL) *charptr = xstrdup(str + len); argv_consume(&ac); break; case oProxyJump: if (str == NULL) { error("%.200s line %d: Missing argument.", filename, linenum); goto out; } len = strspn(str, WHITESPACE "="); /* XXX use argv? */ if (parse_jump(str + len, options, *activep) == -1) { error("%.200s line %d: Invalid ProxyJump \"%s\"", filename, linenum, str + len); goto out; } argv_consume(&ac); break; case oPort: arg = argv_next(&ac, &av); if (!arg || *arg == '\0') { error("%.200s line %d: Missing argument.", filename, linenum); goto out; } value = a2port(arg); if (value <= 0) { error("%.200s line %d: Bad port '%s'.", filename, linenum, arg); goto out; } if (*activep && options->port == -1) options->port = value; break; case oConnectionAttempts: intptr = &options->connection_attempts; parse_int: arg = argv_next(&ac, &av); if ((errstr = atoi_err(arg, &value)) != NULL) { error("%s line %d: integer value %s.", filename, linenum, errstr); goto out; } if (*activep && *intptr == -1) *intptr = value; break; case oCiphers: arg = argv_next(&ac, &av); if (!arg || *arg == '\0') { error("%.200s line %d: Missing argument.", filename, linenum); goto out; } if (*arg != '-' && !ciphers_valid(*arg == '+' || *arg == '^' ? arg + 1 : arg)){ error("%.200s line %d: Bad SSH2 cipher spec '%s'.", filename, linenum, arg ? arg : ""); goto out; } if (*activep && options->ciphers == NULL) options->ciphers = xstrdup(arg); break; case oMacs: arg = argv_next(&ac, &av); if (!arg || *arg == '\0') { error("%.200s line %d: Missing argument.", filename, linenum); goto out; } if (*arg != '-' && !mac_valid(*arg == '+' || *arg == '^' ? arg + 1 : arg)) { error("%.200s line %d: Bad SSH2 MAC spec '%s'.", filename, linenum, arg ? arg : ""); goto out; } if (*activep && options->macs == NULL) options->macs = xstrdup(arg); break; case oKexAlgorithms: arg = argv_next(&ac, &av); if (!arg || *arg == '\0') { error("%.200s line %d: Missing argument.", filename, linenum); goto out; } if (*arg != '-' && !kex_names_valid(*arg == '+' || *arg == '^' ? arg + 1 : arg)) { error("%.200s line %d: Bad SSH2 KexAlgorithms '%s'.", filename, linenum, arg ? arg : ""); goto out; } if (*activep && options->kex_algorithms == NULL) options->kex_algorithms = xstrdup(arg); break; case oHostKeyAlgorithms: charptr = &options->hostkeyalgorithms; parse_pubkey_algos: arg = argv_next(&ac, &av); if (!arg || *arg == '\0') { error("%.200s line %d: Missing argument.", filename, linenum); goto out; } if (*arg != '-' && !sshkey_names_valid2(*arg == '+' || *arg == '^' ? arg + 1 : arg, 1)) { error("%s line %d: Bad key types '%s'.", filename, linenum, arg ? arg : ""); goto out; } if (*activep && *charptr == NULL) *charptr = xstrdup(arg); break; case oCASignatureAlgorithms: charptr = &options->ca_sign_algorithms; goto parse_pubkey_algos; case oLogLevel: log_level_ptr = &options->log_level; arg = argv_next(&ac, &av); value = log_level_number(arg); if (value == SYSLOG_LEVEL_NOT_SET) { error("%.200s line %d: unsupported log level '%s'", filename, linenum, arg ? arg : ""); goto out; } if (*activep && *log_level_ptr == SYSLOG_LEVEL_NOT_SET) *log_level_ptr = (LogLevel) value; break; case oLogFacility: log_facility_ptr = &options->log_facility; arg = argv_next(&ac, &av); value = log_facility_number(arg); if (value == SYSLOG_FACILITY_NOT_SET) { error("%.200s line %d: unsupported log facility '%s'", filename, linenum, arg ? arg : ""); goto out; } if (*log_facility_ptr == -1) *log_facility_ptr = (SyslogFacility) value; break; case oLogVerbose: cppptr = &options->log_verbose; uintptr = &options->num_log_verbose; i = 0; while ((arg = argv_next(&ac, &av)) != NULL) { if (*arg == '\0') { error("%s line %d: keyword %s empty argument", filename, linenum, keyword); goto out; } /* Allow "none" only in first position */ if (strcasecmp(arg, "none") == 0) { if (i > 0 || ac > 0) { error("%s line %d: keyword %s \"none\" " "argument must appear alone.", filename, linenum, keyword); goto out; } } i++; if (*activep && *uintptr == 0) { *cppptr = xrecallocarray(*cppptr, *uintptr, *uintptr + 1, sizeof(**cppptr)); (*cppptr)[(*uintptr)++] = xstrdup(arg); } } break; case oLocalForward: case oRemoteForward: case oDynamicForward: arg = argv_next(&ac, &av); if (!arg || *arg == '\0') { error("%.200s line %d: Missing argument.", filename, linenum); goto out; } remotefwd = (opcode == oRemoteForward); dynamicfwd = (opcode == oDynamicForward); if (!dynamicfwd) { arg2 = argv_next(&ac, &av); if (arg2 == NULL || *arg2 == '\0') { if (remotefwd) dynamicfwd = 1; else { error("%.200s line %d: Missing target " "argument.", filename, linenum); goto out; } } else { /* construct a string for parse_forward */ snprintf(fwdarg, sizeof(fwdarg), "%s:%s", arg, arg2); } } if (dynamicfwd) strlcpy(fwdarg, arg, sizeof(fwdarg)); if (parse_forward(&fwd, fwdarg, dynamicfwd, remotefwd) == 0) { error("%.200s line %d: Bad forwarding specification.", filename, linenum); goto out; } if (*activep) { if (remotefwd) { add_remote_forward(options, &fwd); } else { add_local_forward(options, &fwd); } } break; case oPermitRemoteOpen: uintptr = &options->num_permitted_remote_opens; cppptr = &options->permitted_remote_opens; uvalue = *uintptr; /* modified later */ i = 0; while ((arg = argv_next(&ac, &av)) != NULL) { arg2 = xstrdup(arg); /* Allow any/none only in first position */ if (strcasecmp(arg, "none") == 0 || strcasecmp(arg, "any") == 0) { if (i > 0 || ac > 0) { error("%s line %d: keyword %s \"%s\" " "argument must appear alone.", filename, linenum, keyword, arg); goto out; } } else { p = hpdelim(&arg); if (p == NULL) { fatal("%s line %d: missing host in %s", filename, linenum, lookup_opcode_name(opcode)); } p = cleanhostname(p); /* * don't want to use permitopen_port to avoid * dependency on channels.[ch] here. */ if (arg == NULL || (strcmp(arg, "*") != 0 && a2port(arg) <= 0)) { fatal("%s line %d: bad port number " "in %s", filename, linenum, lookup_opcode_name(opcode)); } } if (*activep && uvalue == 0) { opt_array_append(filename, linenum, lookup_opcode_name(opcode), cppptr, uintptr, arg2); } free(arg2); i++; } if (i == 0) fatal("%s line %d: missing %s specification", filename, linenum, lookup_opcode_name(opcode)); break; case oClearAllForwardings: intptr = &options->clear_forwardings; goto parse_flag; case oHost: if (cmdline) { error("Host directive not supported as a command-line " "option"); goto out; } *activep = 0; arg2 = NULL; while ((arg = argv_next(&ac, &av)) != NULL) { if (*arg == '\0') { error("%s line %d: keyword %s empty argument", filename, linenum, keyword); goto out; } if ((flags & SSHCONF_NEVERMATCH) != 0) { argv_consume(&ac); break; } negated = *arg == '!'; if (negated) arg++; if (match_pattern(host, arg)) { if (negated) { debug("%.200s line %d: Skipping Host " "block because of negated match " "for %.100s", filename, linenum, arg); *activep = 0; argv_consume(&ac); break; } if (!*activep) arg2 = arg; /* logged below */ *activep = 1; } } if (*activep) debug("%.200s line %d: Applying options for %.100s", filename, linenum, arg2); break; case oMatch: if (cmdline) { error("Host directive not supported as a command-line " "option"); goto out; } value = match_cfg_line(options, &str, pw, host, original_host, flags & SSHCONF_FINAL, want_final_pass, filename, linenum); if (value < 0) { error("%.200s line %d: Bad Match condition", filename, linenum); goto out; } *activep = (flags & SSHCONF_NEVERMATCH) ? 0 : value; /* * If match_cfg_line() didn't consume all its arguments then * arrange for the extra arguments check below to fail. */ if (str == NULL || *str == '\0') argv_consume(&ac); break; case oEscapeChar: intptr = &options->escape_char; arg = argv_next(&ac, &av); if (!arg || *arg == '\0') { error("%.200s line %d: Missing argument.", filename, linenum); goto out; } if (strcmp(arg, "none") == 0) value = SSH_ESCAPECHAR_NONE; else if (arg[1] == '\0') value = (u_char) arg[0]; else if (arg[0] == '^' && arg[2] == 0 && (u_char) arg[1] >= 64 && (u_char) arg[1] < 128) value = (u_char) arg[1] & 31; else { error("%.200s line %d: Bad escape character.", filename, linenum); goto out; } if (*activep && *intptr == -1) *intptr = value; break; case oAddressFamily: intptr = &options->address_family; multistate_ptr = multistate_addressfamily; goto parse_multistate; case oEnableSSHKeysign: intptr = &options->enable_ssh_keysign; goto parse_flag; case oIdentitiesOnly: intptr = &options->identities_only; goto parse_flag; case oServerAliveInterval: intptr = &options->server_alive_interval; goto parse_time; case oServerAliveCountMax: intptr = &options->server_alive_count_max; goto parse_int; case oSendEnv: while ((arg = argv_next(&ac, &av)) != NULL) { if (*arg == '\0' || strchr(arg, '=') != NULL) { error("%s line %d: Invalid environment name.", filename, linenum); goto out; } if (!*activep) continue; if (*arg == '-') { /* Removing an env var */ rm_env(options, arg, filename, linenum); continue; } opt_array_append(filename, linenum, lookup_opcode_name(opcode), &options->send_env, &options->num_send_env, arg); } break; case oSetEnv: value = options->num_setenv; while ((arg = argv_next(&ac, &av)) != NULL) { if (strchr(arg, '=') == NULL) { error("%s line %d: Invalid SetEnv.", filename, linenum); goto out; } if (!*activep || value != 0) continue; if (lookup_setenv_in_list(arg, options->setenv, options->num_setenv) != NULL) { debug2("%s line %d: ignoring duplicate env " "name \"%.64s\"", filename, linenum, arg); continue; } opt_array_append(filename, linenum, lookup_opcode_name(opcode), &options->setenv, &options->num_setenv, arg); } break; case oControlPath: charptr = &options->control_path; goto parse_string; case oControlMaster: intptr = &options->control_master; multistate_ptr = multistate_controlmaster; goto parse_multistate; case oControlPersist: /* no/false/yes/true, or a time spec */ intptr = &options->control_persist; arg = argv_next(&ac, &av); if (!arg || *arg == '\0') { error("%.200s line %d: Missing ControlPersist" " argument.", filename, linenum); goto out; } value = 0; value2 = 0; /* timeout */ if (strcmp(arg, "no") == 0 || strcmp(arg, "false") == 0) value = 0; else if (strcmp(arg, "yes") == 0 || strcmp(arg, "true") == 0) value = 1; else if ((value2 = convtime(arg)) >= 0) value = 1; else { error("%.200s line %d: Bad ControlPersist argument.", filename, linenum); goto out; } if (*activep && *intptr == -1) { *intptr = value; options->control_persist_timeout = value2; } break; case oHashKnownHosts: intptr = &options->hash_known_hosts; goto parse_flag; case oTunnel: intptr = &options->tun_open; multistate_ptr = multistate_tunnel; goto parse_multistate; case oTunnelDevice: arg = argv_next(&ac, &av); if (!arg || *arg == '\0') { error("%.200s line %d: Missing argument.", filename, linenum); goto out; } value = a2tun(arg, &value2); if (value == SSH_TUNID_ERR) { error("%.200s line %d: Bad tun device.", filename, linenum); goto out; } if (*activep && options->tun_local == -1) { options->tun_local = value; options->tun_remote = value2; } break; case oLocalCommand: charptr = &options->local_command; goto parse_command; case oPermitLocalCommand: intptr = &options->permit_local_command; goto parse_flag; case oRemoteCommand: charptr = &options->remote_command; goto parse_command; case oVisualHostKey: intptr = &options->visual_host_key; goto parse_flag; case oInclude: if (cmdline) { error("Include directive not supported as a " "command-line option"); goto out; } value = 0; while ((arg = argv_next(&ac, &av)) != NULL) { if (*arg == '\0') { error("%s line %d: keyword %s empty argument", filename, linenum, keyword); goto out; } /* * Ensure all paths are anchored. User configuration * files may begin with '~/' but system configurations * must not. If the path is relative, then treat it * as living in ~/.ssh for user configurations or * /etc/ssh for system ones. */ if (*arg == '~' && (flags & SSHCONF_USERCONF) == 0) { error("%.200s line %d: bad include path %s.", filename, linenum, arg); goto out; } if (!path_absolute(arg) && *arg != '~') { xasprintf(&arg2, "%s/%s", (flags & SSHCONF_USERCONF) ? "~/" _PATH_SSH_USER_DIR : SSHDIR, arg); } else arg2 = xstrdup(arg); memset(&gl, 0, sizeof(gl)); r = glob(arg2, GLOB_TILDE, NULL, &gl); if (r == GLOB_NOMATCH) { debug("%.200s line %d: include %s matched no " "files",filename, linenum, arg2); free(arg2); continue; } else if (r != 0) { error("%.200s line %d: glob failed for %s.", filename, linenum, arg2); goto out; } free(arg2); oactive = *activep; for (i = 0; i < gl.gl_pathc; i++) { debug3("%.200s line %d: Including file %s " "depth %d%s", filename, linenum, gl.gl_pathv[i], depth, oactive ? "" : " (parse only)"); r = read_config_file_depth(gl.gl_pathv[i], pw, host, original_host, options, flags | SSHCONF_CHECKPERM | (oactive ? 0 : SSHCONF_NEVERMATCH), activep, want_final_pass, depth + 1); if (r != 1 && errno != ENOENT) { error("Can't open user config file " "%.100s: %.100s", gl.gl_pathv[i], strerror(errno)); globfree(&gl); goto out; } /* * don't let Match in includes clobber the * containing file's Match state. */ *activep = oactive; if (r != 1) value = -1; } globfree(&gl); } if (value != 0) ret = value; break; case oIPQoS: arg = argv_next(&ac, &av); if ((value = parse_ipqos(arg)) == -1) { error("%s line %d: Bad IPQoS value: %s", filename, linenum, arg); goto out; } arg = argv_next(&ac, &av); if (arg == NULL) value2 = value; else if ((value2 = parse_ipqos(arg)) == -1) { error("%s line %d: Bad IPQoS value: %s", filename, linenum, arg); goto out; } if (*activep && options->ip_qos_interactive == -1) { options->ip_qos_interactive = value; options->ip_qos_bulk = value2; } break; case oRequestTTY: intptr = &options->request_tty; multistate_ptr = multistate_requesttty; goto parse_multistate; case oSessionType: intptr = &options->session_type; multistate_ptr = multistate_sessiontype; goto parse_multistate; case oStdinNull: intptr = &options->stdin_null; goto parse_flag; case oForkAfterAuthentication: intptr = &options->fork_after_authentication; goto parse_flag; case oVersionAddendum: if (str == NULL) fatal("%.200s line %d: Missing argument.", filename, linenum); len = strspn(str, WHITESPACE); if (*activep && options->version_addendum == NULL) { if (strcasecmp(str + len, "none") == 0) options->version_addendum = xstrdup(""); else if (strchr(str + len, '\r') != NULL) fatal("%.200s line %d: Invalid argument", filename, linenum); else options->version_addendum = xstrdup(str + len); } return 0; case oIgnoreUnknown: charptr = &options->ignored_unknown; goto parse_string; case oProxyUseFdpass: intptr = &options->proxy_use_fdpass; goto parse_flag; case oCanonicalDomains: value = options->num_canonical_domains != 0; i = 0; while ((arg = argv_next(&ac, &av)) != NULL) { if (*arg == '\0') { error("%s line %d: keyword %s empty argument", filename, linenum, keyword); goto out; } /* Allow "none" only in first position */ if (strcasecmp(arg, "none") == 0) { if (i > 0 || ac > 0) { error("%s line %d: keyword %s \"none\" " "argument must appear alone.", filename, linenum, keyword); goto out; } } i++; if (!valid_domain(arg, 1, &errstr)) { error("%s line %d: %s", filename, linenum, errstr); goto out; } if (!*activep || value) continue; if (options->num_canonical_domains >= MAX_CANON_DOMAINS) { error("%s line %d: too many hostname suffixes.", filename, linenum); goto out; } options->canonical_domains[ options->num_canonical_domains++] = xstrdup(arg); } break; case oCanonicalizePermittedCNAMEs: value = options->num_permitted_cnames != 0; i = 0; while ((arg = argv_next(&ac, &av)) != NULL) { /* * Either 'none' (only in first position), '*' for * everything or 'list:list' */ if (strcasecmp(arg, "none") == 0) { if (i > 0 || ac > 0) { error("%s line %d: keyword %s \"none\" " "argument must appear alone.", filename, linenum, keyword); goto out; } arg2 = ""; } else if (strcmp(arg, "*") == 0) { arg2 = arg; } else { lowercase(arg); if ((arg2 = strchr(arg, ':')) == NULL || arg2[1] == '\0') { error("%s line %d: " "Invalid permitted CNAME \"%s\"", filename, linenum, arg); goto out; } *arg2 = '\0'; arg2++; } i++; if (!*activep || value) continue; if (options->num_permitted_cnames >= MAX_CANON_DOMAINS) { error("%s line %d: too many permitted CNAMEs.", filename, linenum); goto out; } cname = options->permitted_cnames + options->num_permitted_cnames++; cname->source_list = xstrdup(arg); cname->target_list = xstrdup(arg2); } break; case oCanonicalizeHostname: intptr = &options->canonicalize_hostname; multistate_ptr = multistate_canonicalizehostname; goto parse_multistate; case oCanonicalizeMaxDots: intptr = &options->canonicalize_max_dots; goto parse_int; case oCanonicalizeFallbackLocal: intptr = &options->canonicalize_fallback_local; goto parse_flag; case oStreamLocalBindMask: arg = argv_next(&ac, &av); if (!arg || *arg == '\0') { error("%.200s line %d: Missing StreamLocalBindMask " "argument.", filename, linenum); goto out; } /* Parse mode in octal format */ value = strtol(arg, &endofnumber, 8); if (arg == endofnumber || value < 0 || value > 0777) { error("%.200s line %d: Bad mask.", filename, linenum); goto out; } options->fwd_opts.streamlocal_bind_mask = (mode_t)value; break; case oStreamLocalBindUnlink: intptr = &options->fwd_opts.streamlocal_bind_unlink; goto parse_flag; case oRevokedHostKeys: charptr = &options->revoked_host_keys; goto parse_string; case oFingerprintHash: intptr = &options->fingerprint_hash; arg = argv_next(&ac, &av); if (!arg || *arg == '\0') { error("%.200s line %d: Missing argument.", filename, linenum); goto out; } if ((value = ssh_digest_alg_by_name(arg)) == -1) { error("%.200s line %d: Invalid hash algorithm \"%s\".", filename, linenum, arg); goto out; } if (*activep && *intptr == -1) *intptr = value; break; case oUpdateHostkeys: intptr = &options->update_hostkeys; multistate_ptr = multistate_yesnoask; goto parse_multistate; case oHostbasedAcceptedAlgorithms: charptr = &options->hostbased_accepted_algos; goto parse_pubkey_algos; case oPubkeyAcceptedAlgorithms: charptr = &options->pubkey_accepted_algos; goto parse_pubkey_algos; case oAddKeysToAgent: arg = argv_next(&ac, &av); arg2 = argv_next(&ac, &av); value = parse_multistate_value(arg, filename, linenum, multistate_yesnoaskconfirm); value2 = 0; /* unlimited lifespan by default */ if (value == 3 && arg2 != NULL) { /* allow "AddKeysToAgent confirm 5m" */ if ((value2 = convtime(arg2)) == -1 || value2 > INT_MAX) { error("%s line %d: invalid time value.", filename, linenum); goto out; } } else if (value == -1 && arg2 == NULL) { if ((value2 = convtime(arg)) == -1 || value2 > INT_MAX) { error("%s line %d: unsupported option", filename, linenum); goto out; } value = 1; /* yes */ } else if (value == -1 || arg2 != NULL) { error("%s line %d: unsupported option", filename, linenum); goto out; } if (*activep && options->add_keys_to_agent == -1) { options->add_keys_to_agent = value; options->add_keys_to_agent_lifespan = value2; } break; case oIdentityAgent: charptr = &options->identity_agent; arg = argv_next(&ac, &av); if (!arg || *arg == '\0') { error("%.200s line %d: Missing argument.", filename, linenum); goto out; } parse_agent_path: /* Extra validation if the string represents an env var. */ if ((arg2 = dollar_expand(&r, arg)) == NULL || r) { error("%.200s line %d: Invalid environment expansion " "%s.", filename, linenum, arg); goto out; } free(arg2); /* check for legacy environment format */ if (arg[0] == '$' && arg[1] != '{' && !valid_env_name(arg + 1)) { error("%.200s line %d: Invalid environment name %s.", filename, linenum, arg); goto out; } if (*activep && *charptr == NULL) *charptr = xstrdup(arg); break; case oEnableEscapeCommandline: intptr = &options->enable_escape_commandline; goto parse_flag; case oRequiredRSASize: intptr = &options->required_rsa_size; goto parse_int; case oDeprecated: debug("%s line %d: Deprecated option \"%s\"", filename, linenum, keyword); argv_consume(&ac); break; case oUnsupported: error("%s line %d: Unsupported option \"%s\"", filename, linenum, keyword); argv_consume(&ac); break; default: error("%s line %d: Unimplemented opcode %d", filename, linenum, opcode); goto out; } /* Check that there is no garbage at end of line. */ if (ac > 0) { error("%.200s line %d: keyword %s extra arguments " "at end of line", filename, linenum, keyword); goto out; } /* success */ ret = 0; out: argv_free(oav, oac); return ret; } /* * Reads the config file and modifies the options accordingly. Options * should already be initialized before this call. This never returns if * there is an error. If the file does not exist, this returns 0. */ int read_config_file(const char *filename, struct passwd *pw, const char *host, const char *original_host, Options *options, int flags, int *want_final_pass) { int active = 1; return read_config_file_depth(filename, pw, host, original_host, options, flags, &active, want_final_pass, 0); } #define READCONF_MAX_DEPTH 16 static int read_config_file_depth(const char *filename, struct passwd *pw, const char *host, const char *original_host, Options *options, int flags, int *activep, int *want_final_pass, int depth) { FILE *f; char *line = NULL; size_t linesize = 0; int linenum; int bad_options = 0; if (depth < 0 || depth > READCONF_MAX_DEPTH) fatal("Too many recursive configuration includes"); if ((f = fopen(filename, "r")) == NULL) return 0; if (flags & SSHCONF_CHECKPERM) { struct stat sb; if (fstat(fileno(f), &sb) == -1) fatal("fstat %s: %s", filename, strerror(errno)); if (((sb.st_uid != 0 && sb.st_uid != getuid()) || (sb.st_mode & 022) != 0)) fatal("Bad owner or permissions on %s", filename); } debug("Reading configuration data %.200s", filename); /* * Mark that we are now processing the options. This flag is turned * on/off by Host specifications. */ linenum = 0; while (getline(&line, &linesize, f) != -1) { /* Update line number counter. */ linenum++; /* * Trim out comments and strip whitespace. * NB - preserve newlines, they are needed to reproduce * line numbers later for error messages. */ if (process_config_line_depth(options, pw, host, original_host, line, filename, linenum, activep, flags, want_final_pass, depth) != 0) bad_options++; } free(line); fclose(f); if (bad_options > 0) fatal("%s: terminating, %d bad configuration options", filename, bad_options); return 1; } /* Returns 1 if a string option is unset or set to "none" or 0 otherwise. */ int option_clear_or_none(const char *o) { return o == NULL || strcasecmp(o, "none") == 0; } /* * Returns 1 if CanonicalizePermittedCNAMEs have been specified, 0 otherwise. * Allowed to be called on non-final configuration. */ int config_has_permitted_cnames(Options *options) { if (options->num_permitted_cnames == 1 && strcasecmp(options->permitted_cnames[0].source_list, "none") == 0 && strcmp(options->permitted_cnames[0].target_list, "") == 0) return 0; return options->num_permitted_cnames > 0; } /* * Initializes options to special values that indicate that they have not yet * been set. Read_config_file will only set options with this value. Options * are processed in the following order: command line, user config file, * system config file. Last, fill_default_options is called. */ void initialize_options(Options * options) { memset(options, 'X', sizeof(*options)); options->version_addendum = NULL; options->host_arg = NULL; options->forward_agent = -1; options->forward_agent_sock_path = NULL; options->forward_x11 = -1; options->forward_x11_trusted = -1; options->forward_x11_timeout = -1; options->stdio_forward_host = NULL; options->stdio_forward_port = 0; options->clear_forwardings = -1; options->exit_on_forward_failure = -1; options->xauth_location = NULL; options->fwd_opts.gateway_ports = -1; options->fwd_opts.streamlocal_bind_mask = (mode_t)-1; options->fwd_opts.streamlocal_bind_unlink = -1; options->pubkey_authentication = -1; options->gss_authentication = -1; options->gss_deleg_creds = -1; options->password_authentication = -1; options->kbd_interactive_authentication = -1; options->kbd_interactive_devices = NULL; options->hostbased_authentication = -1; options->batch_mode = -1; options->check_host_ip = -1; options->strict_host_key_checking = -1; options->compression = -1; options->tcp_keep_alive = -1; options->port = -1; options->address_family = -1; options->connection_attempts = -1; options->connection_timeout = -1; options->number_of_password_prompts = -1; options->ciphers = NULL; options->macs = NULL; options->kex_algorithms = NULL; options->hostkeyalgorithms = NULL; options->ca_sign_algorithms = NULL; options->num_identity_files = 0; memset(options->identity_keys, 0, sizeof(options->identity_keys)); options->num_certificate_files = 0; memset(options->certificates, 0, sizeof(options->certificates)); options->hostname = NULL; options->host_key_alias = NULL; options->proxy_command = NULL; options->jump_user = NULL; options->jump_host = NULL; options->jump_port = -1; options->jump_extra = NULL; options->user = NULL; options->escape_char = -1; options->num_system_hostfiles = 0; options->num_user_hostfiles = 0; options->local_forwards = NULL; options->num_local_forwards = 0; options->remote_forwards = NULL; options->num_remote_forwards = 0; options->permitted_remote_opens = NULL; options->num_permitted_remote_opens = 0; options->log_facility = SYSLOG_FACILITY_NOT_SET; options->log_level = SYSLOG_LEVEL_NOT_SET; options->num_log_verbose = 0; options->log_verbose = NULL; options->preferred_authentications = NULL; options->bind_address = NULL; options->bind_interface = NULL; options->pkcs11_provider = NULL; options->sk_provider = NULL; options->enable_ssh_keysign = - 1; options->no_host_authentication_for_localhost = - 1; options->identities_only = - 1; options->rekey_limit = - 1; options->rekey_interval = -1; options->verify_host_key_dns = -1; options->server_alive_interval = -1; options->server_alive_count_max = -1; options->send_env = NULL; options->num_send_env = 0; options->setenv = NULL; options->num_setenv = 0; options->control_path = NULL; options->control_master = -1; options->control_persist = -1; options->control_persist_timeout = 0; options->hash_known_hosts = -1; options->tun_open = -1; options->tun_local = -1; options->tun_remote = -1; options->local_command = NULL; options->permit_local_command = -1; options->remote_command = NULL; options->add_keys_to_agent = -1; options->add_keys_to_agent_lifespan = -1; options->identity_agent = NULL; options->visual_host_key = -1; options->ip_qos_interactive = -1; options->ip_qos_bulk = -1; options->request_tty = -1; options->session_type = -1; options->stdin_null = -1; options->fork_after_authentication = -1; options->proxy_use_fdpass = -1; options->ignored_unknown = NULL; options->num_canonical_domains = 0; options->num_permitted_cnames = 0; options->canonicalize_max_dots = -1; options->canonicalize_fallback_local = -1; options->canonicalize_hostname = -1; options->revoked_host_keys = NULL; options->fingerprint_hash = -1; options->update_hostkeys = -1; options->hostbased_accepted_algos = NULL; options->pubkey_accepted_algos = NULL; options->known_hosts_command = NULL; options->required_rsa_size = -1; options->enable_escape_commandline = -1; } /* * A petite version of fill_default_options() that just fills the options * needed for hostname canonicalization to proceed. */ void fill_default_options_for_canonicalization(Options *options) { if (options->canonicalize_max_dots == -1) options->canonicalize_max_dots = 1; if (options->canonicalize_fallback_local == -1) options->canonicalize_fallback_local = 1; if (options->canonicalize_hostname == -1) options->canonicalize_hostname = SSH_CANONICALISE_NO; } /* * Called after processing other sources of option data, this fills those * options for which no value has been specified with their default values. */ int fill_default_options(Options * options) { char *all_cipher, *all_mac, *all_kex, *all_key, *all_sig; char *def_cipher, *def_mac, *def_kex, *def_key, *def_sig; int ret = 0, r; if (options->forward_agent == -1) options->forward_agent = 0; if (options->forward_x11 == -1) options->forward_x11 = 0; if (options->forward_x11_trusted == -1) options->forward_x11_trusted = 0; if (options->forward_x11_timeout == -1) options->forward_x11_timeout = 1200; /* * stdio forwarding (-W) changes the default for these but we defer * setting the values so they can be overridden. */ if (options->exit_on_forward_failure == -1) options->exit_on_forward_failure = options->stdio_forward_host != NULL ? 1 : 0; if (options->clear_forwardings == -1) options->clear_forwardings = options->stdio_forward_host != NULL ? 1 : 0; if (options->clear_forwardings == 1) clear_forwardings(options); if (options->xauth_location == NULL) options->xauth_location = xstrdup(_PATH_XAUTH); if (options->fwd_opts.gateway_ports == -1) options->fwd_opts.gateway_ports = 0; if (options->fwd_opts.streamlocal_bind_mask == (mode_t)-1) options->fwd_opts.streamlocal_bind_mask = 0177; if (options->fwd_opts.streamlocal_bind_unlink == -1) options->fwd_opts.streamlocal_bind_unlink = 0; if (options->pubkey_authentication == -1) options->pubkey_authentication = SSH_PUBKEY_AUTH_ALL; if (options->gss_authentication == -1) options->gss_authentication = 0; if (options->gss_deleg_creds == -1) options->gss_deleg_creds = 0; if (options->password_authentication == -1) options->password_authentication = 1; if (options->kbd_interactive_authentication == -1) options->kbd_interactive_authentication = 1; if (options->hostbased_authentication == -1) options->hostbased_authentication = 0; if (options->batch_mode == -1) options->batch_mode = 0; if (options->check_host_ip == -1) options->check_host_ip = 0; if (options->strict_host_key_checking == -1) options->strict_host_key_checking = SSH_STRICT_HOSTKEY_ASK; if (options->compression == -1) options->compression = 0; if (options->tcp_keep_alive == -1) options->tcp_keep_alive = 1; if (options->port == -1) options->port = 0; /* Filled in ssh_connect. */ if (options->address_family == -1) options->address_family = AF_UNSPEC; if (options->connection_attempts == -1) options->connection_attempts = 1; if (options->number_of_password_prompts == -1) options->number_of_password_prompts = 3; /* options->hostkeyalgorithms, default set in myproposals.h */ if (options->add_keys_to_agent == -1) { options->add_keys_to_agent = 0; options->add_keys_to_agent_lifespan = 0; } if (options->num_identity_files == 0) { add_identity_file(options, "~/", _PATH_SSH_CLIENT_ID_RSA, 0); #ifdef OPENSSL_HAS_ECC add_identity_file(options, "~/", _PATH_SSH_CLIENT_ID_ECDSA, 0); add_identity_file(options, "~/", _PATH_SSH_CLIENT_ID_ECDSA_SK, 0); #endif add_identity_file(options, "~/", _PATH_SSH_CLIENT_ID_ED25519, 0); add_identity_file(options, "~/", _PATH_SSH_CLIENT_ID_ED25519_SK, 0); add_identity_file(options, "~/", _PATH_SSH_CLIENT_ID_XMSS, 0); add_identity_file(options, "~/", _PATH_SSH_CLIENT_ID_DSA, 0); } if (options->escape_char == -1) options->escape_char = '~'; if (options->num_system_hostfiles == 0) { options->system_hostfiles[options->num_system_hostfiles++] = xstrdup(_PATH_SSH_SYSTEM_HOSTFILE); options->system_hostfiles[options->num_system_hostfiles++] = xstrdup(_PATH_SSH_SYSTEM_HOSTFILE2); } if (options->update_hostkeys == -1) { if (options->verify_host_key_dns <= 0 && (options->num_user_hostfiles == 0 || (options->num_user_hostfiles == 1 && strcmp(options-> user_hostfiles[0], _PATH_SSH_USER_HOSTFILE) == 0))) options->update_hostkeys = SSH_UPDATE_HOSTKEYS_YES; else options->update_hostkeys = SSH_UPDATE_HOSTKEYS_NO; } if (options->num_user_hostfiles == 0) { options->user_hostfiles[options->num_user_hostfiles++] = xstrdup(_PATH_SSH_USER_HOSTFILE); options->user_hostfiles[options->num_user_hostfiles++] = xstrdup(_PATH_SSH_USER_HOSTFILE2); } if (options->log_level == SYSLOG_LEVEL_NOT_SET) options->log_level = SYSLOG_LEVEL_INFO; if (options->log_facility == SYSLOG_FACILITY_NOT_SET) options->log_facility = SYSLOG_FACILITY_USER; if (options->no_host_authentication_for_localhost == - 1) options->no_host_authentication_for_localhost = 0; if (options->identities_only == -1) options->identities_only = 0; if (options->enable_ssh_keysign == -1) options->enable_ssh_keysign = 0; if (options->rekey_limit == -1) options->rekey_limit = 0; if (options->rekey_interval == -1) options->rekey_interval = 0; -#if HAVE_LDNS - if (options->verify_host_key_dns == -1) - /* automatically trust a verified SSHFP record */ - options->verify_host_key_dns = 1; -#else if (options->verify_host_key_dns == -1) options->verify_host_key_dns = 0; -#endif if (options->server_alive_interval == -1) options->server_alive_interval = 0; if (options->server_alive_count_max == -1) options->server_alive_count_max = 3; if (options->control_master == -1) options->control_master = 0; if (options->control_persist == -1) { options->control_persist = 0; options->control_persist_timeout = 0; } if (options->hash_known_hosts == -1) options->hash_known_hosts = 0; if (options->tun_open == -1) options->tun_open = SSH_TUNMODE_NO; if (options->tun_local == -1) options->tun_local = SSH_TUNID_ANY; if (options->tun_remote == -1) options->tun_remote = SSH_TUNID_ANY; if (options->permit_local_command == -1) options->permit_local_command = 0; if (options->visual_host_key == -1) options->visual_host_key = 0; if (options->ip_qos_interactive == -1) options->ip_qos_interactive = IPTOS_DSCP_AF21; if (options->ip_qos_bulk == -1) options->ip_qos_bulk = IPTOS_DSCP_CS1; if (options->request_tty == -1) options->request_tty = REQUEST_TTY_AUTO; if (options->session_type == -1) options->session_type = SESSION_TYPE_DEFAULT; if (options->stdin_null == -1) options->stdin_null = 0; if (options->fork_after_authentication == -1) options->fork_after_authentication = 0; if (options->proxy_use_fdpass == -1) options->proxy_use_fdpass = 0; if (options->canonicalize_max_dots == -1) options->canonicalize_max_dots = 1; if (options->canonicalize_fallback_local == -1) options->canonicalize_fallback_local = 1; if (options->canonicalize_hostname == -1) options->canonicalize_hostname = SSH_CANONICALISE_NO; if (options->fingerprint_hash == -1) options->fingerprint_hash = SSH_FP_HASH_DEFAULT; #ifdef ENABLE_SK_INTERNAL if (options->sk_provider == NULL) options->sk_provider = xstrdup("internal"); #else if (options->sk_provider == NULL) options->sk_provider = xstrdup("$SSH_SK_PROVIDER"); #endif if (options->required_rsa_size == -1) options->required_rsa_size = SSH_RSA_MINIMUM_MODULUS_SIZE; if (options->enable_escape_commandline == -1) options->enable_escape_commandline = 0; /* Expand KEX name lists */ all_cipher = cipher_alg_list(',', 0); all_mac = mac_alg_list(','); all_kex = kex_alg_list(','); all_key = sshkey_alg_list(0, 0, 1, ','); all_sig = sshkey_alg_list(0, 1, 1, ','); /* remove unsupported algos from default lists */ def_cipher = match_filter_allowlist(KEX_CLIENT_ENCRYPT, all_cipher); def_mac = match_filter_allowlist(KEX_CLIENT_MAC, all_mac); def_kex = match_filter_allowlist(KEX_CLIENT_KEX, all_kex); def_key = match_filter_allowlist(KEX_DEFAULT_PK_ALG, all_key); def_sig = match_filter_allowlist(SSH_ALLOWED_CA_SIGALGS, all_sig); #define ASSEMBLE(what, defaults, all) \ do { \ if ((r = kex_assemble_names(&options->what, \ defaults, all)) != 0) { \ error_fr(r, "%s", #what); \ goto fail; \ } \ } while (0) ASSEMBLE(ciphers, def_cipher, all_cipher); ASSEMBLE(macs, def_mac, all_mac); ASSEMBLE(kex_algorithms, def_kex, all_kex); ASSEMBLE(hostbased_accepted_algos, def_key, all_key); ASSEMBLE(pubkey_accepted_algos, def_key, all_key); ASSEMBLE(ca_sign_algorithms, def_sig, all_sig); #undef ASSEMBLE #define CLEAR_ON_NONE(v) \ do { \ if (option_clear_or_none(v)) { \ free(v); \ v = NULL; \ } \ } while(0) CLEAR_ON_NONE(options->local_command); CLEAR_ON_NONE(options->remote_command); CLEAR_ON_NONE(options->proxy_command); CLEAR_ON_NONE(options->control_path); CLEAR_ON_NONE(options->revoked_host_keys); CLEAR_ON_NONE(options->pkcs11_provider); CLEAR_ON_NONE(options->sk_provider); CLEAR_ON_NONE(options->known_hosts_command); if (options->jump_host != NULL && strcmp(options->jump_host, "none") == 0 && options->jump_port == 0 && options->jump_user == NULL) { free(options->jump_host); options->jump_host = NULL; } if (options->num_permitted_cnames == 1 && !config_has_permitted_cnames(options)) { /* clean up CanonicalizePermittedCNAMEs=none */ free(options->permitted_cnames[0].source_list); free(options->permitted_cnames[0].target_list); memset(options->permitted_cnames, '\0', sizeof(*options->permitted_cnames)); options->num_permitted_cnames = 0; } /* options->identity_agent distinguishes NULL from 'none' */ /* options->user will be set in the main program if appropriate */ /* options->hostname will be set in the main program if appropriate */ /* options->host_key_alias should not be set by default */ /* options->preferred_authentications will be set in ssh */ if (options->version_addendum == NULL) options->version_addendum = xstrdup(SSH_VERSION_FREEBSD); /* success */ ret = 0; fail: free(all_cipher); free(all_mac); free(all_kex); free(all_key); free(all_sig); free(def_cipher); free(def_mac); free(def_kex); free(def_key); free(def_sig); return ret; } void free_options(Options *o) { int i; if (o == NULL) return; #define FREE_ARRAY(type, n, a) \ do { \ type _i; \ for (_i = 0; _i < (n); _i++) \ free((a)[_i]); \ } while (0) free(o->forward_agent_sock_path); free(o->xauth_location); FREE_ARRAY(u_int, o->num_log_verbose, o->log_verbose); free(o->log_verbose); free(o->ciphers); free(o->macs); free(o->hostkeyalgorithms); free(o->kex_algorithms); free(o->ca_sign_algorithms); free(o->hostname); free(o->host_key_alias); free(o->proxy_command); free(o->user); FREE_ARRAY(u_int, o->num_system_hostfiles, o->system_hostfiles); FREE_ARRAY(u_int, o->num_user_hostfiles, o->user_hostfiles); free(o->preferred_authentications); free(o->bind_address); free(o->bind_interface); free(o->pkcs11_provider); free(o->sk_provider); for (i = 0; i < o->num_identity_files; i++) { free(o->identity_files[i]); sshkey_free(o->identity_keys[i]); } for (i = 0; i < o->num_certificate_files; i++) { free(o->certificate_files[i]); sshkey_free(o->certificates[i]); } free(o->identity_agent); for (i = 0; i < o->num_local_forwards; i++) { free(o->local_forwards[i].listen_host); free(o->local_forwards[i].listen_path); free(o->local_forwards[i].connect_host); free(o->local_forwards[i].connect_path); } free(o->local_forwards); for (i = 0; i < o->num_remote_forwards; i++) { free(o->remote_forwards[i].listen_host); free(o->remote_forwards[i].listen_path); free(o->remote_forwards[i].connect_host); free(o->remote_forwards[i].connect_path); } free(o->remote_forwards); free(o->stdio_forward_host); FREE_ARRAY(u_int, o->num_send_env, o->send_env); free(o->send_env); FREE_ARRAY(u_int, o->num_setenv, o->setenv); free(o->setenv); free(o->control_path); free(o->local_command); free(o->remote_command); FREE_ARRAY(int, o->num_canonical_domains, o->canonical_domains); for (i = 0; i < o->num_permitted_cnames; i++) { free(o->permitted_cnames[i].source_list); free(o->permitted_cnames[i].target_list); } free(o->revoked_host_keys); free(o->hostbased_accepted_algos); free(o->pubkey_accepted_algos); free(o->jump_user); free(o->jump_host); free(o->jump_extra); free(o->ignored_unknown); explicit_bzero(o, sizeof(*o)); #undef FREE_ARRAY } struct fwdarg { char *arg; int ispath; }; /* * parse_fwd_field * parses the next field in a port forwarding specification. * sets fwd to the parsed field and advances p past the colon * or sets it to NULL at end of string. * returns 0 on success, else non-zero. */ static int parse_fwd_field(char **p, struct fwdarg *fwd) { char *ep, *cp = *p; int ispath = 0; if (*cp == '\0') { *p = NULL; return -1; /* end of string */ } /* * A field escaped with square brackets is used literally. * XXX - allow ']' to be escaped via backslash? */ if (*cp == '[') { /* find matching ']' */ for (ep = cp + 1; *ep != ']' && *ep != '\0'; ep++) { if (*ep == '/') ispath = 1; } /* no matching ']' or not at end of field. */ if (ep[0] != ']' || (ep[1] != ':' && ep[1] != '\0')) return -1; /* NUL terminate the field and advance p past the colon */ *ep++ = '\0'; if (*ep != '\0') *ep++ = '\0'; fwd->arg = cp + 1; fwd->ispath = ispath; *p = ep; return 0; } for (cp = *p; *cp != '\0'; cp++) { switch (*cp) { case '\\': memmove(cp, cp + 1, strlen(cp + 1) + 1); if (*cp == '\0') return -1; break; case '/': ispath = 1; break; case ':': *cp++ = '\0'; goto done; } } done: fwd->arg = *p; fwd->ispath = ispath; *p = cp; return 0; } /* * parse_forward * parses a string containing a port forwarding specification of the form: * dynamicfwd == 0 * [listenhost:]listenport|listenpath:connecthost:connectport|connectpath * listenpath:connectpath * dynamicfwd == 1 * [listenhost:]listenport * returns number of arguments parsed or zero on error */ int parse_forward(struct Forward *fwd, const char *fwdspec, int dynamicfwd, int remotefwd) { struct fwdarg fwdargs[4]; char *p, *cp; int i, err; memset(fwd, 0, sizeof(*fwd)); memset(fwdargs, 0, sizeof(fwdargs)); /* * We expand environment variables before checking if we think they're * paths so that if ${VAR} expands to a fully qualified path it is * treated as a path. */ cp = p = dollar_expand(&err, fwdspec); if (p == NULL || err) return 0; /* skip leading spaces */ while (isspace((u_char)*cp)) cp++; for (i = 0; i < 4; ++i) { if (parse_fwd_field(&cp, &fwdargs[i]) != 0) break; } /* Check for trailing garbage */ if (cp != NULL && *cp != '\0') { i = 0; /* failure */ } switch (i) { case 1: if (fwdargs[0].ispath) { fwd->listen_path = xstrdup(fwdargs[0].arg); fwd->listen_port = PORT_STREAMLOCAL; } else { fwd->listen_host = NULL; fwd->listen_port = a2port(fwdargs[0].arg); } fwd->connect_host = xstrdup("socks"); break; case 2: if (fwdargs[0].ispath && fwdargs[1].ispath) { fwd->listen_path = xstrdup(fwdargs[0].arg); fwd->listen_port = PORT_STREAMLOCAL; fwd->connect_path = xstrdup(fwdargs[1].arg); fwd->connect_port = PORT_STREAMLOCAL; } else if (fwdargs[1].ispath) { fwd->listen_host = NULL; fwd->listen_port = a2port(fwdargs[0].arg); fwd->connect_path = xstrdup(fwdargs[1].arg); fwd->connect_port = PORT_STREAMLOCAL; } else { fwd->listen_host = xstrdup(fwdargs[0].arg); fwd->listen_port = a2port(fwdargs[1].arg); fwd->connect_host = xstrdup("socks"); } break; case 3: if (fwdargs[0].ispath) { fwd->listen_path = xstrdup(fwdargs[0].arg); fwd->listen_port = PORT_STREAMLOCAL; fwd->connect_host = xstrdup(fwdargs[1].arg); fwd->connect_port = a2port(fwdargs[2].arg); } else if (fwdargs[2].ispath) { fwd->listen_host = xstrdup(fwdargs[0].arg); fwd->listen_port = a2port(fwdargs[1].arg); fwd->connect_path = xstrdup(fwdargs[2].arg); fwd->connect_port = PORT_STREAMLOCAL; } else { fwd->listen_host = NULL; fwd->listen_port = a2port(fwdargs[0].arg); fwd->connect_host = xstrdup(fwdargs[1].arg); fwd->connect_port = a2port(fwdargs[2].arg); } break; case 4: fwd->listen_host = xstrdup(fwdargs[0].arg); fwd->listen_port = a2port(fwdargs[1].arg); fwd->connect_host = xstrdup(fwdargs[2].arg); fwd->connect_port = a2port(fwdargs[3].arg); break; default: i = 0; /* failure */ } free(p); if (dynamicfwd) { if (!(i == 1 || i == 2)) goto fail_free; } else { if (!(i == 3 || i == 4)) { if (fwd->connect_path == NULL && fwd->listen_path == NULL) goto fail_free; } if (fwd->connect_port <= 0 && fwd->connect_path == NULL) goto fail_free; } if ((fwd->listen_port < 0 && fwd->listen_path == NULL) || (!remotefwd && fwd->listen_port == 0)) goto fail_free; if (fwd->connect_host != NULL && strlen(fwd->connect_host) >= NI_MAXHOST) goto fail_free; /* * XXX - if connecting to a remote socket, max sun len may not * match this host */ if (fwd->connect_path != NULL && strlen(fwd->connect_path) >= PATH_MAX_SUN) goto fail_free; if (fwd->listen_host != NULL && strlen(fwd->listen_host) >= NI_MAXHOST) goto fail_free; if (fwd->listen_path != NULL && strlen(fwd->listen_path) >= PATH_MAX_SUN) goto fail_free; return (i); fail_free: free(fwd->connect_host); fwd->connect_host = NULL; free(fwd->connect_path); fwd->connect_path = NULL; free(fwd->listen_host); fwd->listen_host = NULL; free(fwd->listen_path); fwd->listen_path = NULL; return (0); } int parse_jump(const char *s, Options *o, int active) { char *orig, *sdup, *cp; char *host = NULL, *user = NULL; int r, ret = -1, port = -1, first; active &= o->proxy_command == NULL && o->jump_host == NULL; orig = sdup = xstrdup(s); /* Remove comment and trailing whitespace */ if ((cp = strchr(orig, '#')) != NULL) *cp = '\0'; rtrim(orig); first = active; do { if (strcasecmp(s, "none") == 0) break; if ((cp = strrchr(sdup, ',')) == NULL) cp = sdup; /* last */ else *cp++ = '\0'; if (first) { /* First argument and configuration is active */ r = parse_ssh_uri(cp, &user, &host, &port); if (r == -1 || (r == 1 && parse_user_host_port(cp, &user, &host, &port) != 0)) goto out; } else { /* Subsequent argument or inactive configuration */ r = parse_ssh_uri(cp, NULL, NULL, NULL); if (r == -1 || (r == 1 && parse_user_host_port(cp, NULL, NULL, NULL) != 0)) goto out; } first = 0; /* only check syntax for subsequent hosts */ } while (cp != sdup); /* success */ if (active) { if (strcasecmp(s, "none") == 0) { o->jump_host = xstrdup("none"); o->jump_port = 0; } else { o->jump_user = user; o->jump_host = host; o->jump_port = port; o->proxy_command = xstrdup("none"); user = host = NULL; if ((cp = strrchr(s, ',')) != NULL && cp != s) { o->jump_extra = xstrdup(s); o->jump_extra[cp - s] = '\0'; } } } ret = 0; out: free(orig); free(user); free(host); return ret; } int parse_ssh_uri(const char *uri, char **userp, char **hostp, int *portp) { char *user = NULL, *host = NULL, *path = NULL; int r, port; r = parse_uri("ssh", uri, &user, &host, &port, &path); if (r == 0 && path != NULL) r = -1; /* path not allowed */ if (r == 0) { if (userp != NULL) { *userp = user; user = NULL; } if (hostp != NULL) { *hostp = host; host = NULL; } if (portp != NULL) *portp = port; } free(user); free(host); free(path); return r; } /* XXX the following is a near-vebatim copy from servconf.c; refactor */ static const char * fmt_multistate_int(int val, const struct multistate *m) { u_int i; for (i = 0; m[i].key != NULL; i++) { if (m[i].value == val) return m[i].key; } return "UNKNOWN"; } static const char * fmt_intarg(OpCodes code, int val) { if (val == -1) return "unset"; switch (code) { case oAddressFamily: return fmt_multistate_int(val, multistate_addressfamily); case oVerifyHostKeyDNS: case oUpdateHostkeys: return fmt_multistate_int(val, multistate_yesnoask); case oStrictHostKeyChecking: return fmt_multistate_int(val, multistate_strict_hostkey); case oControlMaster: return fmt_multistate_int(val, multistate_controlmaster); case oTunnel: return fmt_multistate_int(val, multistate_tunnel); case oRequestTTY: return fmt_multistate_int(val, multistate_requesttty); case oSessionType: return fmt_multistate_int(val, multistate_sessiontype); case oCanonicalizeHostname: return fmt_multistate_int(val, multistate_canonicalizehostname); case oAddKeysToAgent: return fmt_multistate_int(val, multistate_yesnoaskconfirm); case oPubkeyAuthentication: return fmt_multistate_int(val, multistate_pubkey_auth); case oFingerprintHash: return ssh_digest_alg_name(val); default: switch (val) { case 0: return "no"; case 1: return "yes"; default: return "UNKNOWN"; } } } static const char * lookup_opcode_name(OpCodes code) { u_int i; for (i = 0; keywords[i].name != NULL; i++) if (keywords[i].opcode == code) return(keywords[i].name); return "UNKNOWN"; } static void dump_cfg_int(OpCodes code, int val) { printf("%s %d\n", lookup_opcode_name(code), val); } static void dump_cfg_fmtint(OpCodes code, int val) { printf("%s %s\n", lookup_opcode_name(code), fmt_intarg(code, val)); } static void dump_cfg_string(OpCodes code, const char *val) { if (val == NULL) return; printf("%s %s\n", lookup_opcode_name(code), val); } static void dump_cfg_strarray(OpCodes code, u_int count, char **vals) { u_int i; for (i = 0; i < count; i++) printf("%s %s\n", lookup_opcode_name(code), vals[i]); } static void dump_cfg_strarray_oneline(OpCodes code, u_int count, char **vals) { u_int i; printf("%s", lookup_opcode_name(code)); if (count == 0) printf(" none"); for (i = 0; i < count; i++) printf(" %s", vals[i]); printf("\n"); } static void dump_cfg_forwards(OpCodes code, u_int count, const struct Forward *fwds) { const struct Forward *fwd; u_int i; /* oDynamicForward */ for (i = 0; i < count; i++) { fwd = &fwds[i]; if (code == oDynamicForward && fwd->connect_host != NULL && strcmp(fwd->connect_host, "socks") != 0) continue; if (code == oLocalForward && fwd->connect_host != NULL && strcmp(fwd->connect_host, "socks") == 0) continue; printf("%s", lookup_opcode_name(code)); if (fwd->listen_port == PORT_STREAMLOCAL) printf(" %s", fwd->listen_path); else if (fwd->listen_host == NULL) printf(" %d", fwd->listen_port); else { printf(" [%s]:%d", fwd->listen_host, fwd->listen_port); } if (code != oDynamicForward) { if (fwd->connect_port == PORT_STREAMLOCAL) printf(" %s", fwd->connect_path); else if (fwd->connect_host == NULL) printf(" %d", fwd->connect_port); else { printf(" [%s]:%d", fwd->connect_host, fwd->connect_port); } } printf("\n"); } } void dump_client_config(Options *o, const char *host) { int i, r; char buf[8], *all_key; /* * Expand HostKeyAlgorithms name lists. This isn't handled in * fill_default_options() like the other algorithm lists because * the host key algorithms are by default dynamically chosen based * on the host's keys found in known_hosts. */ all_key = sshkey_alg_list(0, 0, 1, ','); if ((r = kex_assemble_names(&o->hostkeyalgorithms, kex_default_pk_alg(), all_key)) != 0) fatal_fr(r, "expand HostKeyAlgorithms"); free(all_key); /* Most interesting options first: user, host, port */ dump_cfg_string(oHost, o->host_arg); dump_cfg_string(oUser, o->user); dump_cfg_string(oHostname, host); dump_cfg_int(oPort, o->port); /* Flag options */ dump_cfg_fmtint(oAddressFamily, o->address_family); dump_cfg_fmtint(oBatchMode, o->batch_mode); dump_cfg_fmtint(oCanonicalizeFallbackLocal, o->canonicalize_fallback_local); dump_cfg_fmtint(oCanonicalizeHostname, o->canonicalize_hostname); dump_cfg_fmtint(oCheckHostIP, o->check_host_ip); dump_cfg_fmtint(oCompression, o->compression); dump_cfg_fmtint(oControlMaster, o->control_master); dump_cfg_fmtint(oEnableSSHKeysign, o->enable_ssh_keysign); dump_cfg_fmtint(oClearAllForwardings, o->clear_forwardings); dump_cfg_fmtint(oExitOnForwardFailure, o->exit_on_forward_failure); dump_cfg_fmtint(oFingerprintHash, o->fingerprint_hash); dump_cfg_fmtint(oForwardX11, o->forward_x11); dump_cfg_fmtint(oForwardX11Trusted, o->forward_x11_trusted); dump_cfg_fmtint(oGatewayPorts, o->fwd_opts.gateway_ports); #ifdef GSSAPI dump_cfg_fmtint(oGssAuthentication, o->gss_authentication); dump_cfg_fmtint(oGssDelegateCreds, o->gss_deleg_creds); #endif /* GSSAPI */ dump_cfg_fmtint(oHashKnownHosts, o->hash_known_hosts); dump_cfg_fmtint(oHostbasedAuthentication, o->hostbased_authentication); dump_cfg_fmtint(oIdentitiesOnly, o->identities_only); dump_cfg_fmtint(oKbdInteractiveAuthentication, o->kbd_interactive_authentication); dump_cfg_fmtint(oNoHostAuthenticationForLocalhost, o->no_host_authentication_for_localhost); dump_cfg_fmtint(oPasswordAuthentication, o->password_authentication); dump_cfg_fmtint(oPermitLocalCommand, o->permit_local_command); dump_cfg_fmtint(oProxyUseFdpass, o->proxy_use_fdpass); dump_cfg_fmtint(oPubkeyAuthentication, o->pubkey_authentication); dump_cfg_fmtint(oRequestTTY, o->request_tty); dump_cfg_fmtint(oSessionType, o->session_type); dump_cfg_fmtint(oStdinNull, o->stdin_null); dump_cfg_fmtint(oForkAfterAuthentication, o->fork_after_authentication); dump_cfg_fmtint(oStreamLocalBindUnlink, o->fwd_opts.streamlocal_bind_unlink); dump_cfg_fmtint(oStrictHostKeyChecking, o->strict_host_key_checking); dump_cfg_fmtint(oTCPKeepAlive, o->tcp_keep_alive); dump_cfg_fmtint(oTunnel, o->tun_open); dump_cfg_fmtint(oVerifyHostKeyDNS, o->verify_host_key_dns); dump_cfg_fmtint(oVisualHostKey, o->visual_host_key); dump_cfg_fmtint(oUpdateHostkeys, o->update_hostkeys); dump_cfg_fmtint(oEnableEscapeCommandline, o->enable_escape_commandline); /* Integer options */ dump_cfg_int(oCanonicalizeMaxDots, o->canonicalize_max_dots); dump_cfg_int(oConnectionAttempts, o->connection_attempts); dump_cfg_int(oForwardX11Timeout, o->forward_x11_timeout); dump_cfg_int(oNumberOfPasswordPrompts, o->number_of_password_prompts); dump_cfg_int(oServerAliveCountMax, o->server_alive_count_max); dump_cfg_int(oServerAliveInterval, o->server_alive_interval); dump_cfg_int(oRequiredRSASize, o->required_rsa_size); /* String options */ dump_cfg_string(oBindAddress, o->bind_address); dump_cfg_string(oBindInterface, o->bind_interface); dump_cfg_string(oCiphers, o->ciphers); dump_cfg_string(oControlPath, o->control_path); dump_cfg_string(oHostKeyAlgorithms, o->hostkeyalgorithms); dump_cfg_string(oHostKeyAlias, o->host_key_alias); dump_cfg_string(oHostbasedAcceptedAlgorithms, o->hostbased_accepted_algos); dump_cfg_string(oIdentityAgent, o->identity_agent); dump_cfg_string(oIgnoreUnknown, o->ignored_unknown); dump_cfg_string(oKbdInteractiveDevices, o->kbd_interactive_devices); dump_cfg_string(oKexAlgorithms, o->kex_algorithms); dump_cfg_string(oCASignatureAlgorithms, o->ca_sign_algorithms); dump_cfg_string(oLocalCommand, o->local_command); dump_cfg_string(oRemoteCommand, o->remote_command); dump_cfg_string(oLogLevel, log_level_name(o->log_level)); dump_cfg_string(oMacs, o->macs); #ifdef ENABLE_PKCS11 dump_cfg_string(oPKCS11Provider, o->pkcs11_provider); #endif dump_cfg_string(oSecurityKeyProvider, o->sk_provider); dump_cfg_string(oPreferredAuthentications, o->preferred_authentications); dump_cfg_string(oPubkeyAcceptedAlgorithms, o->pubkey_accepted_algos); dump_cfg_string(oRevokedHostKeys, o->revoked_host_keys); dump_cfg_string(oXAuthLocation, o->xauth_location); dump_cfg_string(oKnownHostsCommand, o->known_hosts_command); /* Forwards */ dump_cfg_forwards(oDynamicForward, o->num_local_forwards, o->local_forwards); dump_cfg_forwards(oLocalForward, o->num_local_forwards, o->local_forwards); dump_cfg_forwards(oRemoteForward, o->num_remote_forwards, o->remote_forwards); /* String array options */ dump_cfg_strarray(oIdentityFile, o->num_identity_files, o->identity_files); dump_cfg_strarray_oneline(oCanonicalDomains, o->num_canonical_domains, o->canonical_domains); dump_cfg_strarray(oCertificateFile, o->num_certificate_files, o->certificate_files); dump_cfg_strarray_oneline(oGlobalKnownHostsFile, o->num_system_hostfiles, o->system_hostfiles); dump_cfg_strarray_oneline(oUserKnownHostsFile, o->num_user_hostfiles, o->user_hostfiles); dump_cfg_strarray(oSendEnv, o->num_send_env, o->send_env); dump_cfg_strarray(oSetEnv, o->num_setenv, o->setenv); dump_cfg_strarray_oneline(oLogVerbose, o->num_log_verbose, o->log_verbose); /* Special cases */ /* PermitRemoteOpen */ if (o->num_permitted_remote_opens == 0) printf("%s any\n", lookup_opcode_name(oPermitRemoteOpen)); else dump_cfg_strarray_oneline(oPermitRemoteOpen, o->num_permitted_remote_opens, o->permitted_remote_opens); /* AddKeysToAgent */ if (o->add_keys_to_agent_lifespan <= 0) dump_cfg_fmtint(oAddKeysToAgent, o->add_keys_to_agent); else { printf("addkeystoagent%s %d\n", o->add_keys_to_agent == 3 ? " confirm" : "", o->add_keys_to_agent_lifespan); } /* oForwardAgent */ if (o->forward_agent_sock_path == NULL) dump_cfg_fmtint(oForwardAgent, o->forward_agent); else dump_cfg_string(oForwardAgent, o->forward_agent_sock_path); /* oConnectTimeout */ if (o->connection_timeout == -1) printf("connecttimeout none\n"); else dump_cfg_int(oConnectTimeout, o->connection_timeout); /* oTunnelDevice */ printf("tunneldevice"); if (o->tun_local == SSH_TUNID_ANY) printf(" any"); else printf(" %d", o->tun_local); if (o->tun_remote == SSH_TUNID_ANY) printf(":any"); else printf(":%d", o->tun_remote); printf("\n"); /* oCanonicalizePermittedCNAMEs */ printf("canonicalizePermittedcnames"); if (o->num_permitted_cnames == 0) printf(" none"); for (i = 0; i < o->num_permitted_cnames; i++) { printf(" %s:%s", o->permitted_cnames[i].source_list, o->permitted_cnames[i].target_list); } printf("\n"); /* oControlPersist */ if (o->control_persist == 0 || o->control_persist_timeout == 0) dump_cfg_fmtint(oControlPersist, o->control_persist); else dump_cfg_int(oControlPersist, o->control_persist_timeout); /* oEscapeChar */ if (o->escape_char == SSH_ESCAPECHAR_NONE) printf("escapechar none\n"); else { vis(buf, o->escape_char, VIS_WHITE, 0); printf("escapechar %s\n", buf); } /* oIPQoS */ printf("ipqos %s ", iptos2str(o->ip_qos_interactive)); printf("%s\n", iptos2str(o->ip_qos_bulk)); /* oRekeyLimit */ printf("rekeylimit %llu %d\n", (unsigned long long)o->rekey_limit, o->rekey_interval); /* oStreamLocalBindMask */ printf("streamlocalbindmask 0%o\n", o->fwd_opts.streamlocal_bind_mask); /* oLogFacility */ printf("syslogfacility %s\n", log_facility_name(o->log_facility)); /* oProxyCommand / oProxyJump */ if (o->jump_host == NULL) dump_cfg_string(oProxyCommand, o->proxy_command); else { /* Check for numeric addresses */ i = strchr(o->jump_host, ':') != NULL || strspn(o->jump_host, "1234567890.") == strlen(o->jump_host); snprintf(buf, sizeof(buf), "%d", o->jump_port); printf("proxyjump %s%s%s%s%s%s%s%s%s\n", /* optional additional jump spec */ o->jump_extra == NULL ? "" : o->jump_extra, o->jump_extra == NULL ? "" : ",", /* optional user */ o->jump_user == NULL ? "" : o->jump_user, o->jump_user == NULL ? "" : "@", /* opening [ if hostname is numeric */ i ? "[" : "", /* mandatory hostname */ o->jump_host, /* closing ] if hostname is numeric */ i ? "]" : "", /* optional port number */ o->jump_port <= 0 ? "" : ":", o->jump_port <= 0 ? "" : buf); } } diff --git a/crypto/openssh/ssh_config b/crypto/openssh/ssh_config index 7c7ad542e4ef..2dee303a128e 100644 --- a/crypto/openssh/ssh_config +++ b/crypto/openssh/ssh_config @@ -1,48 +1,47 @@ # $OpenBSD: ssh_config,v 1.35 2020/07/17 03:43:42 dtucker Exp $ # This is the ssh client system-wide configuration file. See # ssh_config(5) for more information. This file provides defaults for # users, and the values can be changed in per-user configuration files # or on the command line. # Configuration data is parsed as follows: # 1. command line options # 2. user-specific file # 3. system-wide file # Any configuration value is only changed the first time it is set. # Thus, host-specific definitions should be at the beginning of the # configuration file, and defaults at the end. # Site-wide defaults for some commonly used options. For a comprehensive # list of available options, their meanings and defaults, please see the # ssh_config(5) man page. # Host * # ForwardAgent no # ForwardX11 no # PasswordAuthentication yes # HostbasedAuthentication no # GSSAPIAuthentication no # GSSAPIDelegateCredentials no # BatchMode no # CheckHostIP no # AddressFamily any # ConnectTimeout 0 # StrictHostKeyChecking ask # IdentityFile ~/.ssh/id_rsa # IdentityFile ~/.ssh/id_dsa # IdentityFile ~/.ssh/id_ecdsa # IdentityFile ~/.ssh/id_ed25519 # Port 22 # Ciphers aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc # MACs hmac-md5,hmac-sha1,umac-64@openssh.com # EscapeChar ~ # Tunnel no # TunnelDevice any:any # PermitLocalCommand no # VisualHostKey no # ProxyCommand ssh -q -W %h:%p gateway.example.com # RekeyLimit 1G 1h # UserKnownHostsFile ~/.ssh/known_hosts.d/%k -# VerifyHostKeyDNS yes # VersionAddendum FreeBSD-20220415 diff --git a/crypto/openssh/ssh_config.5 b/crypto/openssh/ssh_config.5 index b642c5a6b17a..d783ea6ff835 100644 --- a/crypto/openssh/ssh_config.5 +++ b/crypto/openssh/ssh_config.5 @@ -1,2224 +1,2221 @@ .\" .\" Author: Tatu Ylonen .\" 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". .\" .\" Copyright (c) 1999,2000 Markus Friedl. All rights reserved. .\" Copyright (c) 1999 Aaron Campbell. All rights reserved. .\" Copyright (c) 1999 Theo de Raadt. 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. .\" .\" $OpenBSD: ssh_config.5,v 1.378 2023/01/13 07:13:40 jmc Exp $ .Dd $Mdocdate: January 13 2023 $ .Dt SSH_CONFIG 5 .Os .Sh NAME .Nm ssh_config .Nd OpenSSH client configuration file .Sh DESCRIPTION .Xr ssh 1 obtains configuration data from the following sources in the following order: .Pp .Bl -enum -offset indent -compact .It command-line options .It user's configuration file .Pq Pa ~/.ssh/config .It system-wide configuration file .Pq Pa /etc/ssh/ssh_config .El .Pp For each parameter, the first obtained value will be used. The configuration files contain sections separated by .Cm Host specifications, and that section is only applied for hosts that match one of the patterns given in the specification. The matched host name is usually the one given on the command line (see the .Cm CanonicalizeHostname option for exceptions). .Pp Since the first obtained value for each parameter is used, more host-specific declarations should be given near the beginning of the file, and general defaults at the end. .Pp The file contains keyword-argument pairs, one per line. Lines starting with .Ql # and empty lines are interpreted as comments. Arguments may optionally be enclosed in double quotes .Pq \&" in order to represent arguments containing spaces. Configuration options may be separated by whitespace or optional whitespace and exactly one .Ql = ; the latter format is useful to avoid the need to quote whitespace when specifying configuration options using the .Nm ssh , .Nm scp , and .Nm sftp .Fl o option. .Pp The possible keywords and their meanings are as follows (note that keywords are case-insensitive and arguments are case-sensitive): .Bl -tag -width Ds .It Cm Host Restricts the following declarations (up to the next .Cm Host or .Cm Match keyword) to be only for those hosts that match one of the patterns given after the keyword. If more than one pattern is provided, they should be separated by whitespace. A single .Ql * as a pattern can be used to provide global defaults for all hosts. The host is usually the .Ar hostname argument given on the command line (see the .Cm CanonicalizeHostname keyword for exceptions). .Pp A pattern entry may be negated by prefixing it with an exclamation mark .Pq Sq !\& . If a negated entry is matched, then the .Cm Host entry is ignored, regardless of whether any other patterns on the line match. Negated matches are therefore useful to provide exceptions for wildcard matches. .Pp See .Sx PATTERNS for more information on patterns. .It Cm Match Restricts the following declarations (up to the next .Cm Host or .Cm Match keyword) to be used only when the conditions following the .Cm Match keyword are satisfied. Match conditions are specified using one or more criteria or the single token .Cm all which always matches. The available criteria keywords are: .Cm canonical , .Cm final , .Cm exec , .Cm host , .Cm originalhost , .Cm user , and .Cm localuser . The .Cm all criteria must appear alone or immediately after .Cm canonical or .Cm final . Other criteria may be combined arbitrarily. All criteria but .Cm all , .Cm canonical , and .Cm final require an argument. Criteria may be negated by prepending an exclamation mark .Pq Sq !\& . .Pp The .Cm canonical keyword matches only when the configuration file is being re-parsed after hostname canonicalization (see the .Cm CanonicalizeHostname option). This may be useful to specify conditions that work with canonical host names only. .Pp The .Cm final keyword requests that the configuration be re-parsed (regardless of whether .Cm CanonicalizeHostname is enabled), and matches only during this final pass. If .Cm CanonicalizeHostname is enabled, then .Cm canonical and .Cm final match during the same pass. .Pp The .Cm exec keyword executes the specified command under the user's shell. If the command returns a zero exit status then the condition is considered true. Commands containing whitespace characters must be quoted. Arguments to .Cm exec accept the tokens described in the .Sx TOKENS section. .Pp The other keywords' criteria must be single entries or comma-separated lists and may use the wildcard and negation operators described in the .Sx PATTERNS section. The criteria for the .Cm host keyword are matched against the target hostname, after any substitution by the .Cm Hostname or .Cm CanonicalizeHostname options. The .Cm originalhost keyword matches against the hostname as it was specified on the command-line. The .Cm user keyword matches against the target username on the remote host. The .Cm localuser keyword matches against the name of the local user running .Xr ssh 1 (this keyword may be useful in system-wide .Nm files). .It Cm AddKeysToAgent Specifies whether keys should be automatically added to a running .Xr ssh-agent 1 . If this option is set to .Cm yes and a key is loaded from a file, the key and its passphrase are added to the agent with the default lifetime, as if by .Xr ssh-add 1 . If this option is set to .Cm ask , .Xr ssh 1 will require confirmation using the .Ev SSH_ASKPASS program before adding a key (see .Xr ssh-add 1 for details). If this option is set to .Cm confirm , each use of the key must be confirmed, as if the .Fl c option was specified to .Xr ssh-add 1 . If this option is set to .Cm no , no keys are added to the agent. Alternately, this option may be specified as a time interval using the format described in the .Sx TIME FORMATS section of .Xr sshd_config 5 to specify the key's lifetime in .Xr ssh-agent 1 , after which it will automatically be removed. The argument must be .Cm no (the default), .Cm yes , .Cm confirm (optionally followed by a time interval), .Cm ask or a time interval. .It Cm AddressFamily Specifies which address family to use when connecting. Valid arguments are .Cm any (the default), .Cm inet (use IPv4 only), or .Cm inet6 (use IPv6 only). .It Cm BatchMode If set to .Cm yes , user interaction such as password prompts and host key confirmation requests will be disabled. This option is useful in scripts and other batch jobs where no user is present to interact with .Xr ssh 1 . The argument must be .Cm yes or .Cm no (the default). .It Cm BindAddress Use the specified address on the local machine as the source address of the connection. Only useful on systems with more than one address. .It Cm BindInterface Use the address of the specified interface on the local machine as the source address of the connection. .It Cm CanonicalDomains When .Cm CanonicalizeHostname is enabled, this option specifies the list of domain suffixes in which to search for the specified destination host. .It Cm CanonicalizeFallbackLocal Specifies whether to fail with an error when hostname canonicalization fails. The default, .Cm yes , will attempt to look up the unqualified hostname using the system resolver's search rules. A value of .Cm no will cause .Xr ssh 1 to fail instantly if .Cm CanonicalizeHostname is enabled and the target hostname cannot be found in any of the domains specified by .Cm CanonicalDomains . .It Cm CanonicalizeHostname Controls whether explicit hostname canonicalization is performed. The default, .Cm no , is not to perform any name rewriting and let the system resolver handle all hostname lookups. If set to .Cm yes then, for connections that do not use a .Cm ProxyCommand or .Cm ProxyJump , .Xr ssh 1 will attempt to canonicalize the hostname specified on the command line using the .Cm CanonicalDomains suffixes and .Cm CanonicalizePermittedCNAMEs rules. If .Cm CanonicalizeHostname is set to .Cm always , then canonicalization is applied to proxied connections too. .Pp If this option is enabled, then the configuration files are processed again using the new target name to pick up any new configuration in matching .Cm Host and .Cm Match stanzas. A value of .Cm none disables the use of a .Cm ProxyJump host. .It Cm CanonicalizeMaxDots Specifies the maximum number of dot characters in a hostname before canonicalization is disabled. The default, 1, allows a single dot (i.e. hostname.subdomain). .It Cm CanonicalizePermittedCNAMEs Specifies rules to determine whether CNAMEs should be followed when canonicalizing hostnames. The rules consist of one or more arguments of .Ar source_domain_list : Ns Ar target_domain_list , where .Ar source_domain_list is a pattern-list of domains that may follow CNAMEs in canonicalization, and .Ar target_domain_list is a pattern-list of domains that they may resolve to. .Pp For example, .Qq *.a.example.com:*.b.example.com,*.c.example.com will allow hostnames matching .Qq *.a.example.com to be canonicalized to names in the .Qq *.b.example.com or .Qq *.c.example.com domains. .Pp A single argument of .Qq none causes no CNAMEs to be considered for canonicalization. This is the default behaviour. .It Cm CASignatureAlgorithms Specifies which algorithms are allowed for signing of certificates by certificate authorities (CAs). The default is: .Bd -literal -offset indent ssh-ed25519,ecdsa-sha2-nistp256, ecdsa-sha2-nistp384,ecdsa-sha2-nistp521, sk-ssh-ed25519@openssh.com, sk-ecdsa-sha2-nistp256@openssh.com, rsa-sha2-512,rsa-sha2-256 .Ed .Pp If the specified list begins with a .Sq + character, then the specified algorithms will be appended to the default set instead of replacing them. If the specified list begins with a .Sq - character, then the specified algorithms (including wildcards) will be removed from the default set instead of replacing them. .Pp .Xr ssh 1 will not accept host certificates signed using algorithms other than those specified. .It Cm CertificateFile Specifies a file from which the user's certificate is read. A corresponding private key must be provided separately in order to use this certificate either from an .Cm IdentityFile directive or .Fl i flag to .Xr ssh 1 , via .Xr ssh-agent 1 , or via a .Cm PKCS11Provider or .Cm SecurityKeyProvider . .Pp Arguments to .Cm CertificateFile may use the tilde syntax to refer to a user's home directory, the tokens described in the .Sx TOKENS section and environment variables as described in the .Sx ENVIRONMENT VARIABLES section. .Pp It is possible to have multiple certificate files specified in configuration files; these certificates will be tried in sequence. Multiple .Cm CertificateFile directives will add to the list of certificates used for authentication. .It Cm CheckHostIP If set to .Cm yes , .Xr ssh 1 will additionally check the host IP address in the .Pa known_hosts file. This allows it to detect if a host key changed due to DNS spoofing and will add addresses of destination hosts to .Pa ~/.ssh/known_hosts in the process, regardless of the setting of .Cm StrictHostKeyChecking . If the option is set to .Cm no (the default), the check will not be executed. The default is .Cm no . .It Cm Ciphers Specifies the ciphers allowed and their order of preference. Multiple ciphers must be comma-separated. If the specified list begins with a .Sq + character, then the specified ciphers will be appended to the default set instead of replacing them. If the specified list begins with a .Sq - character, then the specified ciphers (including wildcards) will be removed from the default set instead of replacing them. If the specified list begins with a .Sq ^ character, then the specified ciphers will be placed at the head of the default set. .Pp The supported ciphers are: .Bd -literal -offset indent 3des-cbc aes128-cbc aes192-cbc aes256-cbc aes128-ctr aes192-ctr aes256-ctr aes128-gcm@openssh.com aes256-gcm@openssh.com chacha20-poly1305@openssh.com .Ed .Pp The default is: .Bd -literal -offset indent chacha20-poly1305@openssh.com, aes128-ctr,aes192-ctr,aes256-ctr, aes128-gcm@openssh.com,aes256-gcm@openssh.com .Ed .Pp The list of available ciphers may also be obtained using .Qq ssh -Q cipher . .It Cm ClearAllForwardings Specifies that all local, remote, and dynamic port forwardings specified in the configuration files or on the command line be cleared. This option is primarily useful when used from the .Xr ssh 1 command line to clear port forwardings set in configuration files, and is automatically set by .Xr scp 1 and .Xr sftp 1 . The argument must be .Cm yes or .Cm no (the default). .It Cm Compression Specifies whether to use compression. The argument must be .Cm yes or .Cm no (the default). .It Cm ConnectionAttempts Specifies the number of tries (one per second) to make before exiting. The argument must be an integer. This may be useful in scripts if the connection sometimes fails. The default is 1. .It Cm ConnectTimeout Specifies the timeout (in seconds) used when connecting to the SSH server, instead of using the default system TCP timeout. This timeout is applied both to establishing the connection and to performing the initial SSH protocol handshake and key exchange. .It Cm ControlMaster Enables the sharing of multiple sessions over a single network connection. When set to .Cm yes , .Xr ssh 1 will listen for connections on a control socket specified using the .Cm ControlPath argument. Additional sessions can connect to this socket using the same .Cm ControlPath with .Cm ControlMaster set to .Cm no (the default). These sessions will try to reuse the master instance's network connection rather than initiating new ones, but will fall back to connecting normally if the control socket does not exist, or is not listening. .Pp Setting this to .Cm ask will cause .Xr ssh 1 to listen for control connections, but require confirmation using .Xr ssh-askpass 1 . If the .Cm ControlPath cannot be opened, .Xr ssh 1 will continue without connecting to a master instance. .Pp X11 and .Xr ssh-agent 1 forwarding is supported over these multiplexed connections, however the display and agent forwarded will be the one belonging to the master connection i.e. it is not possible to forward multiple displays or agents. .Pp Two additional options allow for opportunistic multiplexing: try to use a master connection but fall back to creating a new one if one does not already exist. These options are: .Cm auto and .Cm autoask . The latter requires confirmation like the .Cm ask option. .It Cm ControlPath Specify the path to the control socket used for connection sharing as described in the .Cm ControlMaster section above or the string .Cm none to disable connection sharing. Arguments to .Cm ControlPath may use the tilde syntax to refer to a user's home directory, the tokens described in the .Sx TOKENS section and environment variables as described in the .Sx ENVIRONMENT VARIABLES section. It is recommended that any .Cm ControlPath used for opportunistic connection sharing include at least %h, %p, and %r (or alternatively %C) and be placed in a directory that is not writable by other users. This ensures that shared connections are uniquely identified. .It Cm ControlPersist When used in conjunction with .Cm ControlMaster , specifies that the master connection should remain open in the background (waiting for future client connections) after the initial client connection has been closed. If set to .Cm no (the default), then the master connection will not be placed into the background, and will close as soon as the initial client connection is closed. If set to .Cm yes or 0, then the master connection will remain in the background indefinitely (until killed or closed via a mechanism such as the .Qq ssh -O exit ) . If set to a time in seconds, or a time in any of the formats documented in .Xr sshd_config 5 , then the backgrounded master connection will automatically terminate after it has remained idle (with no client connections) for the specified time. .It Cm DynamicForward Specifies that a TCP port on the local machine be forwarded over the secure channel, and the application protocol is then used to determine where to connect to from the remote machine. .Pp The argument must be .Sm off .Oo Ar bind_address : Oc Ar port . .Sm on IPv6 addresses can be specified by enclosing addresses in square brackets. By default, the local port is bound in accordance with the .Cm GatewayPorts setting. However, an explicit .Ar bind_address may be used to bind the connection to a specific address. The .Ar bind_address of .Cm localhost indicates that the listening port be bound for local use only, while an empty address or .Sq * indicates that the port should be available from all interfaces. .Pp Currently the SOCKS4 and SOCKS5 protocols are supported, and .Xr ssh 1 will act as a SOCKS server. Multiple forwardings may be specified, and additional forwardings can be given on the command line. Only the superuser can forward privileged ports. .It Cm EnableEscapeCommandline Enables the command line option in the .Cm EscapeChar menu for interactive sessions (default .Ql ~C ) . By default, the command line is disabled. .It Cm EnableSSHKeysign Setting this option to .Cm yes in the global client configuration file .Pa /etc/ssh/ssh_config enables the use of the helper program .Xr ssh-keysign 8 during .Cm HostbasedAuthentication . The argument must be .Cm yes or .Cm no (the default). This option should be placed in the non-hostspecific section. See .Xr ssh-keysign 8 for more information. .It Cm EscapeChar Sets the escape character (default: .Ql ~ ) . The escape character can also be set on the command line. The argument should be a single character, .Ql ^ followed by a letter, or .Cm none to disable the escape character entirely (making the connection transparent for binary data). .It Cm ExitOnForwardFailure Specifies whether .Xr ssh 1 should terminate the connection if it cannot set up all requested dynamic, tunnel, local, and remote port forwardings, (e.g.\& if either end is unable to bind and listen on a specified port). Note that .Cm ExitOnForwardFailure does not apply to connections made over port forwardings and will not, for example, cause .Xr ssh 1 to exit if TCP connections to the ultimate forwarding destination fail. The argument must be .Cm yes or .Cm no (the default). .It Cm FingerprintHash Specifies the hash algorithm used when displaying key fingerprints. Valid options are: .Cm md5 and .Cm sha256 (the default). .It Cm ForkAfterAuthentication Requests .Nm ssh to go to background just before command execution. This is useful if .Nm ssh is going to ask for passwords or passphrases, but the user wants it in the background. This implies the .Cm StdinNull configuration option being set to .Dq yes . The recommended way to start X11 programs at a remote site is with something like .Ic ssh -f host xterm , which is the same as .Ic ssh host xterm if the .Cm ForkAfterAuthentication configuration option is set to .Dq yes . .Pp If the .Cm ExitOnForwardFailure configuration option is set to .Dq yes , then a client started with the .Cm ForkAfterAuthentication configuration option being set to .Dq yes will wait for all remote port forwards to be successfully established before placing itself in the background. The argument to this keyword must be .Cm yes (same as the .Fl f option) or .Cm no (the default). .It Cm ForwardAgent Specifies whether the connection to the authentication agent (if any) will be forwarded to the remote machine. The argument may be .Cm yes , .Cm no (the default), an explicit path to an agent socket or the name of an environment variable (beginning with .Sq $ ) in which to find the path. .Pp Agent forwarding should be enabled with caution. Users with the ability to bypass file permissions on the remote host (for the agent's Unix-domain socket) can access the local agent through the forwarded connection. An attacker cannot obtain key material from the agent, however they can perform operations on the keys that enable them to authenticate using the identities loaded into the agent. .It Cm ForwardX11 Specifies whether X11 connections will be automatically redirected over the secure channel and .Ev DISPLAY set. The argument must be .Cm yes or .Cm no (the default). .Pp X11 forwarding should be enabled with caution. Users with the ability to bypass file permissions on the remote host (for the user's X11 authorization database) can access the local X11 display through the forwarded connection. An attacker may then be able to perform activities such as keystroke monitoring if the .Cm ForwardX11Trusted option is also enabled. .It Cm ForwardX11Timeout Specify a timeout for untrusted X11 forwarding using the format described in the .Sx TIME FORMATS section of .Xr sshd_config 5 . X11 connections received by .Xr ssh 1 after this time will be refused. Setting .Cm ForwardX11Timeout to zero will disable the timeout and permit X11 forwarding for the life of the connection. The default is to disable untrusted X11 forwarding after twenty minutes has elapsed. .It Cm ForwardX11Trusted If this option is set to .Cm yes , remote X11 clients will have full access to the original X11 display. .Pp If this option is set to .Cm no (the default), remote X11 clients will be considered untrusted and prevented from stealing or tampering with data belonging to trusted X11 clients. Furthermore, the .Xr xauth 1 token used for the session will be set to expire after 20 minutes. Remote clients will be refused access after this time. .Pp See the X11 SECURITY extension specification for full details on the restrictions imposed on untrusted clients. .It Cm GatewayPorts Specifies whether remote hosts are allowed to connect to local forwarded ports. By default, .Xr ssh 1 binds local port forwardings to the loopback address. This prevents other remote hosts from connecting to forwarded ports. .Cm GatewayPorts can be used to specify that ssh should bind local port forwardings to the wildcard address, thus allowing remote hosts to connect to forwarded ports. The argument must be .Cm yes or .Cm no (the default). .It Cm GlobalKnownHostsFile Specifies one or more files to use for the global host key database, separated by whitespace. The default is .Pa /etc/ssh/ssh_known_hosts , .Pa /etc/ssh/ssh_known_hosts2 . .It Cm GSSAPIAuthentication Specifies whether user authentication based on GSSAPI is allowed. The default is .Cm no . .It Cm GSSAPIDelegateCredentials Forward (delegate) credentials to the server. The default is .Cm no . .It Cm HashKnownHosts Indicates that .Xr ssh 1 should hash host names and addresses when they are added to .Pa ~/.ssh/known_hosts . These hashed names may be used normally by .Xr ssh 1 and .Xr sshd 8 , but they do not visually reveal identifying information if the file's contents are disclosed. The default is .Cm no . Note that existing names and addresses in known hosts files will not be converted automatically, but may be manually hashed using .Xr ssh-keygen 1 . .It Cm HostbasedAcceptedAlgorithms Specifies the signature algorithms that will be used for hostbased authentication as a comma-separated list of patterns. Alternately if the specified list begins with a .Sq + character, then the specified signature algorithms will be appended to the default set instead of replacing them. If the specified list begins with a .Sq - character, then the specified signature algorithms (including wildcards) will be removed from the default set instead of replacing them. If the specified list begins with a .Sq ^ character, then the specified signature algorithms will be placed at the head of the default set. The default for this option is: .Bd -literal -offset 3n ssh-ed25519-cert-v01@openssh.com, ecdsa-sha2-nistp256-cert-v01@openssh.com, ecdsa-sha2-nistp384-cert-v01@openssh.com, ecdsa-sha2-nistp521-cert-v01@openssh.com, sk-ssh-ed25519-cert-v01@openssh.com, sk-ecdsa-sha2-nistp256-cert-v01@openssh.com, rsa-sha2-512-cert-v01@openssh.com, rsa-sha2-256-cert-v01@openssh.com, ssh-rsa-cert-v01@openssh.com, ssh-ed25519, ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521, sk-ssh-ed25519@openssh.com, sk-ecdsa-sha2-nistp256@openssh.com, rsa-sha2-512,rsa-sha2-256,ssh-rsa .Ed .Pp The .Fl Q option of .Xr ssh 1 may be used to list supported signature algorithms. This was formerly named HostbasedKeyTypes. .It Cm HostbasedAuthentication Specifies whether to try rhosts based authentication with public key authentication. The argument must be .Cm yes or .Cm no (the default). .It Cm HostKeyAlgorithms Specifies the host key signature algorithms that the client wants to use in order of preference. Alternately if the specified list begins with a .Sq + character, then the specified signature algorithms will be appended to the default set instead of replacing them. If the specified list begins with a .Sq - character, then the specified signature algorithms (including wildcards) will be removed from the default set instead of replacing them. If the specified list begins with a .Sq ^ character, then the specified signature algorithms will be placed at the head of the default set. The default for this option is: .Bd -literal -offset 3n ssh-ed25519-cert-v01@openssh.com, ecdsa-sha2-nistp256-cert-v01@openssh.com, ecdsa-sha2-nistp384-cert-v01@openssh.com, ecdsa-sha2-nistp521-cert-v01@openssh.com, sk-ssh-ed25519-cert-v01@openssh.com, sk-ecdsa-sha2-nistp256-cert-v01@openssh.com, rsa-sha2-512-cert-v01@openssh.com, rsa-sha2-256-cert-v01@openssh.com, ssh-rsa-cert-v01@openssh.com, ssh-ed25519, ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521, sk-ecdsa-sha2-nistp256@openssh.com, sk-ssh-ed25519@openssh.com, rsa-sha2-512,rsa-sha2-256,ssh-rsa .Ed .Pp If hostkeys are known for the destination host then this default is modified to prefer their algorithms. .Pp The list of available signature algorithms may also be obtained using .Qq ssh -Q HostKeyAlgorithms . .It Cm HostKeyAlias Specifies an alias that should be used instead of the real host name when looking up or saving the host key in the host key database files and when validating host certificates. This option is useful for tunneling SSH connections or for multiple servers running on a single host. .It Cm Hostname Specifies the real host name to log into. This can be used to specify nicknames or abbreviations for hosts. Arguments to .Cm Hostname accept the tokens described in the .Sx TOKENS section. Numeric IP addresses are also permitted (both on the command line and in .Cm Hostname specifications). The default is the name given on the command line. .It Cm IdentitiesOnly Specifies that .Xr ssh 1 should only use the configured authentication identity and certificate files (either the default files, or those explicitly configured in the .Nm files or passed on the .Xr ssh 1 command-line), even if .Xr ssh-agent 1 or a .Cm PKCS11Provider or .Cm SecurityKeyProvider offers more identities. The argument to this keyword must be .Cm yes or .Cm no (the default). This option is intended for situations where ssh-agent offers many different identities. .It Cm IdentityAgent Specifies the .Ux Ns -domain socket used to communicate with the authentication agent. .Pp This option overrides the .Ev SSH_AUTH_SOCK environment variable and can be used to select a specific agent. Setting the socket name to .Cm none disables the use of an authentication agent. If the string .Qq SSH_AUTH_SOCK is specified, the location of the socket will be read from the .Ev SSH_AUTH_SOCK environment variable. Otherwise if the specified value begins with a .Sq $ character, then it will be treated as an environment variable containing the location of the socket. .Pp Arguments to .Cm IdentityAgent may use the tilde syntax to refer to a user's home directory, the tokens described in the .Sx TOKENS section and environment variables as described in the .Sx ENVIRONMENT VARIABLES section. .It Cm IdentityFile Specifies a file from which the user's DSA, ECDSA, authenticator-hosted ECDSA, Ed25519, authenticator-hosted Ed25519 or RSA authentication identity is read. You can also specify a public key file to use the corresponding private key that is loaded in .Xr ssh-agent 1 when the private key file is not present locally. The default is .Pa ~/.ssh/id_rsa , .Pa ~/.ssh/id_ecdsa , .Pa ~/.ssh/id_ecdsa_sk , .Pa ~/.ssh/id_ed25519 , .Pa ~/.ssh/id_ed25519_sk and .Pa ~/.ssh/id_dsa . Additionally, any identities represented by the authentication agent will be used for authentication unless .Cm IdentitiesOnly is set. If no certificates have been explicitly specified by .Cm CertificateFile , .Xr ssh 1 will try to load certificate information from the filename obtained by appending .Pa -cert.pub to the path of a specified .Cm IdentityFile . .Pp Arguments to .Cm IdentityFile may use the tilde syntax to refer to a user's home directory or the tokens described in the .Sx TOKENS section. .Pp It is possible to have multiple identity files specified in configuration files; all these identities will be tried in sequence. Multiple .Cm IdentityFile directives will add to the list of identities tried (this behaviour differs from that of other configuration directives). .Pp .Cm IdentityFile may be used in conjunction with .Cm IdentitiesOnly to select which identities in an agent are offered during authentication. .Cm IdentityFile may also be used in conjunction with .Cm CertificateFile in order to provide any certificate also needed for authentication with the identity. .It Cm IgnoreUnknown Specifies a pattern-list of unknown options to be ignored if they are encountered in configuration parsing. This may be used to suppress errors if .Nm contains options that are unrecognised by .Xr ssh 1 . It is recommended that .Cm IgnoreUnknown be listed early in the configuration file as it will not be applied to unknown options that appear before it. .It Cm Include Include the specified configuration file(s). Multiple pathnames may be specified and each pathname may contain .Xr glob 7 wildcards and, for user configurations, shell-like .Sq ~ references to user home directories. Wildcards will be expanded and processed in lexical order. Files without absolute paths are assumed to be in .Pa ~/.ssh if included in a user configuration file or .Pa /etc/ssh if included from the system configuration file. .Cm Include directive may appear inside a .Cm Match or .Cm Host block to perform conditional inclusion. .It Cm IPQoS Specifies the IPv4 type-of-service or DSCP class for connections. Accepted values are .Cm af11 , .Cm af12 , .Cm af13 , .Cm af21 , .Cm af22 , .Cm af23 , .Cm af31 , .Cm af32 , .Cm af33 , .Cm af41 , .Cm af42 , .Cm af43 , .Cm cs0 , .Cm cs1 , .Cm cs2 , .Cm cs3 , .Cm cs4 , .Cm cs5 , .Cm cs6 , .Cm cs7 , .Cm ef , .Cm le , .Cm lowdelay , .Cm throughput , .Cm reliability , a numeric value, or .Cm none to use the operating system default. This option may take one or two arguments, separated by whitespace. If one argument is specified, it is used as the packet class unconditionally. If two values are specified, the first is automatically selected for interactive sessions and the second for non-interactive sessions. The default is .Cm af21 (Low-Latency Data) for interactive sessions and .Cm cs1 (Lower Effort) for non-interactive sessions. .It Cm KbdInteractiveAuthentication Specifies whether to use keyboard-interactive authentication. The argument to this keyword must be .Cm yes (the default) or .Cm no . .Cm ChallengeResponseAuthentication is a deprecated alias for this. .It Cm KbdInteractiveDevices Specifies the list of methods to use in keyboard-interactive authentication. Multiple method names must be comma-separated. The default is to use the server specified list. The methods available vary depending on what the server supports. For an OpenSSH server, it may be zero or more of: .Cm bsdauth and .Cm pam . .It Cm KexAlgorithms Specifies the available KEX (Key Exchange) algorithms. Multiple algorithms must be comma-separated. If the specified list begins with a .Sq + character, then the specified algorithms will be appended to the default set instead of replacing them. If the specified list begins with a .Sq - character, then the specified algorithms (including wildcards) will be removed from the default set instead of replacing them. If the specified list begins with a .Sq ^ character, then the specified algorithms will be placed at the head of the default set. The default is: .Bd -literal -offset indent sntrup761x25519-sha512@openssh.com, curve25519-sha256,curve25519-sha256@libssh.org, ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521, diffie-hellman-group-exchange-sha256, diffie-hellman-group16-sha512, diffie-hellman-group18-sha512, diffie-hellman-group14-sha256 .Ed .Pp The list of available key exchange algorithms may also be obtained using .Qq ssh -Q kex . .It Cm KnownHostsCommand Specifies a command to use to obtain a list of host keys, in addition to those listed in .Cm UserKnownHostsFile and .Cm GlobalKnownHostsFile . This command is executed after the files have been read. It may write host key lines to standard output in identical format to the usual files (described in the .Sx VERIFYING HOST KEYS section in .Xr ssh 1 ) . Arguments to .Cm KnownHostsCommand accept the tokens described in the .Sx TOKENS section. The command may be invoked multiple times per connection: once when preparing the preference list of host key algorithms to use, again to obtain the host key for the requested host name and, if .Cm CheckHostIP is enabled, one more time to obtain the host key matching the server's address. If the command exits abnormally or returns a non-zero exit status then the connection is terminated. .It Cm LocalCommand Specifies a command to execute on the local machine after successfully connecting to the server. The command string extends to the end of the line, and is executed with the user's shell. Arguments to .Cm LocalCommand accept the tokens described in the .Sx TOKENS section. .Pp The command is run synchronously and does not have access to the session of the .Xr ssh 1 that spawned it. It should not be used for interactive commands. .Pp This directive is ignored unless .Cm PermitLocalCommand has been enabled. .It Cm LocalForward Specifies that a TCP port on the local machine be forwarded over the secure channel to the specified host and port from the remote machine. The first argument specifies the listener and may be .Sm off .Oo Ar bind_address : Oc Ar port .Sm on or a Unix domain socket path. The second argument is the destination and may be .Ar host : Ns Ar hostport or a Unix domain socket path if the remote host supports it. .Pp IPv6 addresses can be specified by enclosing addresses in square brackets. Multiple forwardings may be specified, and additional forwardings can be given on the command line. Only the superuser can forward privileged ports. By default, the local port is bound in accordance with the .Cm GatewayPorts setting. However, an explicit .Ar bind_address may be used to bind the connection to a specific address. The .Ar bind_address of .Cm localhost indicates that the listening port be bound for local use only, while an empty address or .Sq * indicates that the port should be available from all interfaces. Unix domain socket paths may use the tokens described in the .Sx TOKENS section and environment variables as described in the .Sx ENVIRONMENT VARIABLES section. .It Cm LogLevel Gives the verbosity level that is used when logging messages from .Xr ssh 1 . The possible values are: QUIET, FATAL, ERROR, INFO, VERBOSE, DEBUG, DEBUG1, DEBUG2, and DEBUG3. The default is INFO. DEBUG and DEBUG1 are equivalent. DEBUG2 and DEBUG3 each specify higher levels of verbose output. .It Cm LogVerbose Specify one or more overrides to LogLevel. An override consists of a pattern lists that matches the source file, function and line number to force detailed logging for. For example, an override pattern of: .Bd -literal -offset indent kex.c:*:1000,*:kex_exchange_identification():*,packet.c:* .Ed .Pp would enable detailed logging for line 1000 of .Pa kex.c , everything in the .Fn kex_exchange_identification function, and all code in the .Pa packet.c file. This option is intended for debugging and no overrides are enabled by default. .It Cm MACs Specifies the MAC (message authentication code) algorithms in order of preference. The MAC algorithm is used for data integrity protection. Multiple algorithms must be comma-separated. If the specified list begins with a .Sq + character, then the specified algorithms will be appended to the default set instead of replacing them. If the specified list begins with a .Sq - character, then the specified algorithms (including wildcards) will be removed from the default set instead of replacing them. If the specified list begins with a .Sq ^ character, then the specified algorithms will be placed at the head of the default set. .Pp The algorithms that contain .Qq -etm calculate the MAC after encryption (encrypt-then-mac). These are considered safer and their use recommended. .Pp The default is: .Bd -literal -offset indent umac-64-etm@openssh.com,umac-128-etm@openssh.com, hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com, hmac-sha1-etm@openssh.com, umac-64@openssh.com,umac-128@openssh.com, hmac-sha2-256,hmac-sha2-512,hmac-sha1 .Ed .Pp The list of available MAC algorithms may also be obtained using .Qq ssh -Q mac . .It Cm NoHostAuthenticationForLocalhost Disable host authentication for localhost (loopback addresses). The argument to this keyword must be .Cm yes or .Cm no (the default). .It Cm NumberOfPasswordPrompts Specifies the number of password prompts before giving up. The argument to this keyword must be an integer. The default is 3. .It Cm PasswordAuthentication Specifies whether to use password authentication. The argument to this keyword must be .Cm yes (the default) or .Cm no . .It Cm PermitLocalCommand Allow local command execution via the .Ic LocalCommand option or using the .Ic !\& Ns Ar command escape sequence in .Xr ssh 1 . The argument must be .Cm yes or .Cm no (the default). .It Cm PermitRemoteOpen Specifies the destinations to which remote TCP port forwarding is permitted when .Cm RemoteForward is used as a SOCKS proxy. The forwarding specification must be one of the following forms: .Pp .Bl -item -offset indent -compact .It .Cm PermitRemoteOpen .Sm off .Ar host : port .Sm on .It .Cm PermitRemoteOpen .Sm off .Ar IPv4_addr : port .Sm on .It .Cm PermitRemoteOpen .Sm off .Ar \&[ IPv6_addr \&] : port .Sm on .El .Pp Multiple forwards may be specified by separating them with whitespace. An argument of .Cm any can be used to remove all restrictions and permit any forwarding requests. An argument of .Cm none can be used to prohibit all forwarding requests. The wildcard .Sq * can be used for host or port to allow all hosts or ports respectively. Otherwise, no pattern matching or address lookups are performed on supplied names. .It Cm PKCS11Provider Specifies which PKCS#11 provider to use or .Cm none to indicate that no provider should be used (the default). The argument to this keyword is a path to the PKCS#11 shared library .Xr ssh 1 should use to communicate with a PKCS#11 token providing keys for user authentication. .It Cm Port Specifies the port number to connect on the remote host. The default is 22. .It Cm PreferredAuthentications Specifies the order in which the client should try authentication methods. This allows a client to prefer one method (e.g.\& .Cm keyboard-interactive ) over another method (e.g.\& .Cm password ) . The default is: .Bd -literal -offset indent gssapi-with-mic,hostbased,publickey, keyboard-interactive,password .Ed .It Cm ProxyCommand Specifies the command to use to connect to the server. The command string extends to the end of the line, and is executed using the user's shell .Ql exec directive to avoid a lingering shell process. .Pp Arguments to .Cm ProxyCommand accept the tokens described in the .Sx TOKENS section. The command can be basically anything, and should read from its standard input and write to its standard output. It should eventually connect an .Xr sshd 8 server running on some machine, or execute .Ic sshd -i somewhere. Host key management will be done using the .Cm Hostname of the host being connected (defaulting to the name typed by the user). Setting the command to .Cm none disables this option entirely. Note that .Cm CheckHostIP is not available for connects with a proxy command. .Pp This directive is useful in conjunction with .Xr nc 1 and its proxy support. For example, the following directive would connect via an HTTP proxy at 192.0.2.0: .Bd -literal -offset 3n ProxyCommand /usr/bin/nc -X connect -x 192.0.2.0:8080 %h %p .Ed .It Cm ProxyJump Specifies one or more jump proxies as either .Xo .Sm off .Op Ar user No @ .Ar host .Op : Ns Ar port .Sm on or an ssh URI .Xc . Multiple proxies may be separated by comma characters and will be visited sequentially. Setting this option will cause .Xr ssh 1 to connect to the target host by first making a .Xr ssh 1 connection to the specified .Cm ProxyJump host and then establishing a TCP forwarding to the ultimate target from there. Setting the host to .Cm none disables this option entirely. .Pp Note that this option will compete with the .Cm ProxyCommand option - whichever is specified first will prevent later instances of the other from taking effect. .Pp Note also that the configuration for the destination host (either supplied via the command-line or the configuration file) is not generally applied to jump hosts. .Pa ~/.ssh/config should be used if specific configuration is required for jump hosts. .It Cm ProxyUseFdpass Specifies that .Cm ProxyCommand will pass a connected file descriptor back to .Xr ssh 1 instead of continuing to execute and pass data. The default is .Cm no . .It Cm PubkeyAcceptedAlgorithms Specifies the signature algorithms that will be used for public key authentication as a comma-separated list of patterns. If the specified list begins with a .Sq + character, then the algorithms after it will be appended to the default instead of replacing it. If the specified list begins with a .Sq - character, then the specified algorithms (including wildcards) will be removed from the default set instead of replacing them. If the specified list begins with a .Sq ^ character, then the specified algorithms will be placed at the head of the default set. The default for this option is: .Bd -literal -offset 3n ssh-ed25519-cert-v01@openssh.com, ecdsa-sha2-nistp256-cert-v01@openssh.com, ecdsa-sha2-nistp384-cert-v01@openssh.com, ecdsa-sha2-nistp521-cert-v01@openssh.com, sk-ssh-ed25519-cert-v01@openssh.com, sk-ecdsa-sha2-nistp256-cert-v01@openssh.com, rsa-sha2-512-cert-v01@openssh.com, rsa-sha2-256-cert-v01@openssh.com, -ssh-rsa-cert-v01@openssh.com, ssh-ed25519, ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521, sk-ssh-ed25519@openssh.com, sk-ecdsa-sha2-nistp256@openssh.com, rsa-sha2-512,rsa-sha2-256,ssh-rsa .Ed .Pp The list of available signature algorithms may also be obtained using .Qq ssh -Q PubkeyAcceptedAlgorithms . .It Cm PubkeyAuthentication Specifies whether to try public key authentication. The argument to this keyword must be .Cm yes (the default), .Cm no , .Cm unbound or .Cm host-bound . The final two options enable public key authentication while respectively disabling or enabling the OpenSSH host-bound authentication protocol extension required for restricted .Xr ssh-agent 1 forwarding. .It Cm RekeyLimit Specifies the maximum amount of data that may be transmitted or received before the session key is renegotiated, optionally followed by a maximum amount of time that may pass before the session key is renegotiated. The first argument is specified in bytes and may have a suffix of .Sq K , .Sq M , or .Sq G to indicate Kilobytes, Megabytes, or Gigabytes, respectively. The default is between .Sq 1G and .Sq 4G , depending on the cipher. The optional second value is specified in seconds and may use any of the units documented in the TIME FORMATS section of .Xr sshd_config 5 . The default value for .Cm RekeyLimit is .Cm default none , which means that rekeying is performed after the cipher's default amount of data has been sent or received and no time based rekeying is done. .It Cm RemoteCommand Specifies a command to execute on the remote machine after successfully connecting to the server. The command string extends to the end of the line, and is executed with the user's shell. Arguments to .Cm RemoteCommand accept the tokens described in the .Sx TOKENS section. .It Cm RemoteForward Specifies that a TCP port on the remote machine be forwarded over the secure channel. The remote port may either be forwarded to a specified host and port from the local machine, or may act as a SOCKS 4/5 proxy that allows a remote client to connect to arbitrary destinations from the local machine. The first argument is the listening specification and may be .Sm off .Oo Ar bind_address : Oc Ar port .Sm on or, if the remote host supports it, a Unix domain socket path. If forwarding to a specific destination then the second argument must be .Ar host : Ns Ar hostport or a Unix domain socket path, otherwise if no destination argument is specified then the remote forwarding will be established as a SOCKS proxy. When acting as a SOCKS proxy, the destination of the connection can be restricted by .Cm PermitRemoteOpen . .Pp IPv6 addresses can be specified by enclosing addresses in square brackets. Multiple forwardings may be specified, and additional forwardings can be given on the command line. Privileged ports can be forwarded only when logging in as root on the remote machine. Unix domain socket paths may use the tokens described in the .Sx TOKENS section and environment variables as described in the .Sx ENVIRONMENT VARIABLES section. .Pp If the .Ar port argument is 0, the listen port will be dynamically allocated on the server and reported to the client at run time. .Pp If the .Ar bind_address is not specified, the default is to only bind to loopback addresses. If the .Ar bind_address is .Ql * or an empty string, then the forwarding is requested to listen on all interfaces. Specifying a remote .Ar bind_address will only succeed if the server's .Cm GatewayPorts option is enabled (see .Xr sshd_config 5 ) . .It Cm RequestTTY Specifies whether to request a pseudo-tty for the session. The argument may be one of: .Cm no (never request a TTY), .Cm yes (always request a TTY when standard input is a TTY), .Cm force (always request a TTY) or .Cm auto (request a TTY when opening a login session). This option mirrors the .Fl t and .Fl T flags for .Xr ssh 1 . .It Cm RequiredRSASize Specifies the minimum RSA key size (in bits) that .Xr ssh 1 will accept. User authentication keys smaller than this limit will be ignored. Servers that present host keys smaller than this limit will cause the connection to be terminated. The default is .Cm 1024 bits. Note that this limit may only be raised from the default. .It Cm RevokedHostKeys Specifies revoked host public keys. Keys listed in this file will be refused for host authentication. Note that if this file does not exist or is not readable, then host authentication will be refused for all hosts. Keys may be specified as a text file, listing one public key per line, or as an OpenSSH Key Revocation List (KRL) as generated by .Xr ssh-keygen 1 . For more information on KRLs, see the KEY REVOCATION LISTS section in .Xr ssh-keygen 1 . .It Cm SecurityKeyProvider Specifies a path to a library that will be used when loading any FIDO authenticator-hosted keys, overriding the default of using the built-in USB HID support. .Pp If the specified value begins with a .Sq $ character, then it will be treated as an environment variable containing the path to the library. .It Cm SendEnv Specifies what variables from the local .Xr environ 7 should be sent to the server. The server must also support it, and the server must be configured to accept these environment variables. Note that the .Ev TERM environment variable is always sent whenever a pseudo-terminal is requested as it is required by the protocol. Refer to .Cm AcceptEnv in .Xr sshd_config 5 for how to configure the server. Variables are specified by name, which may contain wildcard characters. Multiple environment variables may be separated by whitespace or spread across multiple .Cm SendEnv directives. .Pp See .Sx PATTERNS for more information on patterns. .Pp It is possible to clear previously set .Cm SendEnv variable names by prefixing patterns with .Pa - . The default is not to send any environment variables. .It Cm ServerAliveCountMax Sets the number of server alive messages (see below) which may be sent without .Xr ssh 1 receiving any messages back from the server. If this threshold is reached while server alive messages are being sent, ssh will disconnect from the server, terminating the session. It is important to note that the use of server alive messages is very different from .Cm TCPKeepAlive (below). The server alive messages are sent through the encrypted channel and therefore will not be spoofable. The TCP keepalive option enabled by .Cm TCPKeepAlive is spoofable. The server alive mechanism is valuable when the client or server depend on knowing when a connection has become unresponsive. .Pp The default value is 3. If, for example, .Cm ServerAliveInterval (see below) is set to 15 and .Cm ServerAliveCountMax is left at the default, if the server becomes unresponsive, ssh will disconnect after approximately 45 seconds. .It Cm ServerAliveInterval Sets a timeout interval in seconds after which if no data has been received from the server, .Xr ssh 1 will send a message through the encrypted channel to request a response from the server. The default is 0, indicating that these messages will not be sent to the server. .It Cm SessionType May be used to either request invocation of a subsystem on the remote system, or to prevent the execution of a remote command at all. The latter is useful for just forwarding ports. The argument to this keyword must be .Cm none (same as the .Fl N option), .Cm subsystem (same as the .Fl s option) or .Cm default (shell or command execution). .It Cm SetEnv Directly specify one or more environment variables and their contents to be sent to the server. Similarly to .Cm SendEnv , with the exception of the .Ev TERM variable, the server must be prepared to accept the environment variable. .It Cm StdinNull Redirects stdin from .Pa /dev/null (actually, prevents reading from stdin). Either this or the equivalent .Fl n option must be used when .Nm ssh is run in the background. The argument to this keyword must be .Cm yes (same as the .Fl n option) or .Cm no (the default). .It Cm StreamLocalBindMask Sets the octal file creation mode mask .Pq umask used when creating a Unix-domain socket file for local or remote port forwarding. This option is only used for port forwarding to a Unix-domain socket file. .Pp The default value is 0177, which creates a Unix-domain socket file that is readable and writable only by the owner. Note that not all operating systems honor the file mode on Unix-domain socket files. .It Cm StreamLocalBindUnlink Specifies whether to remove an existing Unix-domain socket file for local or remote port forwarding before creating a new one. If the socket file already exists and .Cm StreamLocalBindUnlink is not enabled, .Nm ssh will be unable to forward the port to the Unix-domain socket file. This option is only used for port forwarding to a Unix-domain socket file. .Pp The argument must be .Cm yes or .Cm no (the default). .It Cm StrictHostKeyChecking If this flag is set to .Cm yes , .Xr ssh 1 will never automatically add host keys to the .Pa ~/.ssh/known_hosts file, and refuses to connect to hosts whose host key has changed. This provides maximum protection against man-in-the-middle (MITM) attacks, though it can be annoying when the .Pa /etc/ssh/ssh_known_hosts file is poorly maintained or when connections to new hosts are frequently made. This option forces the user to manually add all new hosts. .Pp If this flag is set to .Cm accept-new then ssh will automatically add new host keys to the user's .Pa known_hosts file, but will not permit connections to hosts with changed host keys. If this flag is set to .Cm no or .Cm off , ssh will automatically add new host keys to the user known hosts files and allow connections to hosts with changed hostkeys to proceed, subject to some restrictions. If this flag is set to .Cm ask (the default), new host keys will be added to the user known host files only after the user has confirmed that is what they really want to do, and ssh will refuse to connect to hosts whose host key has changed. The host keys of known hosts will be verified automatically in all cases. .It Cm SyslogFacility Gives the facility code that is used when logging messages from .Xr ssh 1 . The possible values are: DAEMON, USER, AUTH, LOCAL0, LOCAL1, LOCAL2, LOCAL3, LOCAL4, LOCAL5, LOCAL6, LOCAL7. The default is USER. .It Cm TCPKeepAlive Specifies whether the system should send TCP keepalive messages to the other side. If they are sent, death of the connection or crash of one of the machines will be properly noticed. However, this means that connections will die if the route is down temporarily, and some people find it annoying. .Pp The default is .Cm yes (to send TCP keepalive messages), and the client will notice if the network goes down or the remote host dies. This is important in scripts, and many users want it too. .Pp To disable TCP keepalive messages, the value should be set to .Cm no . See also .Cm ServerAliveInterval for protocol-level keepalives. .It Cm Tunnel Request .Xr tun 4 device forwarding between the client and the server. The argument must be .Cm yes , .Cm point-to-point (layer 3), .Cm ethernet (layer 2), or .Cm no (the default). Specifying .Cm yes requests the default tunnel mode, which is .Cm point-to-point . .It Cm TunnelDevice Specifies the .Xr tun 4 devices to open on the client .Pq Ar local_tun and the server .Pq Ar remote_tun . .Pp The argument must be .Sm off .Ar local_tun Op : Ar remote_tun . .Sm on The devices may be specified by numerical ID or the keyword .Cm any , which uses the next available tunnel device. If .Ar remote_tun is not specified, it defaults to .Cm any . The default is .Cm any:any . .It Cm UpdateHostKeys Specifies whether .Xr ssh 1 should accept notifications of additional hostkeys from the server sent after authentication has completed and add them to .Cm UserKnownHostsFile . The argument must be .Cm yes , .Cm no or .Cm ask . This option allows learning alternate hostkeys for a server and supports graceful key rotation by allowing a server to send replacement public keys before old ones are removed. .Pp Additional hostkeys are only accepted if the key used to authenticate the host was already trusted or explicitly accepted by the user, the host was authenticated via .Cm UserKnownHostsFile (i.e. not .Cm GlobalKnownHostsFile ) and the host was authenticated using a plain key and not a certificate. .Pp .Cm UpdateHostKeys is enabled by default if the user has not overridden the default .Cm UserKnownHostsFile setting and has not enabled .Cm VerifyHostKeyDNS , otherwise .Cm UpdateHostKeys will be set to .Cm no . .Pp If .Cm UpdateHostKeys is set to .Cm ask , then the user is asked to confirm the modifications to the known_hosts file. Confirmation is currently incompatible with .Cm ControlPersist , and will be disabled if it is enabled. .Pp Presently, only .Xr sshd 8 from OpenSSH 6.8 and greater support the .Qq hostkeys@openssh.com protocol extension used to inform the client of all the server's hostkeys. .It Cm User Specifies the user to log in as. This can be useful when a different user name is used on different machines. This saves the trouble of having to remember to give the user name on the command line. .It Cm UserKnownHostsFile Specifies one or more files to use for the user host key database, separated by whitespace. Each filename may use tilde notation to refer to the user's home directory, the tokens described in the .Sx TOKENS section and environment variables as described in the .Sx ENVIRONMENT VARIABLES section. A value of .Cm none causes .Xr ssh 1 to ignore any user-specific known hosts files. The default is .Pa ~/.ssh/known_hosts , .Pa ~/.ssh/known_hosts2 . .It Cm VerifyHostKeyDNS Specifies whether to verify the remote key using DNS and SSHFP resource records. If this option is set to .Cm yes , the client will implicitly trust keys that match a secure fingerprint from DNS. Insecure fingerprints will be handled as if this option was set to .Cm ask . If this option is set to .Cm ask , information on fingerprint match will be displayed, but the user will still need to confirm new host keys according to the .Cm StrictHostKeyChecking option. The default is -.Cm yes -if compiled with LDNS and -.Cm no -otherwise. +.Cm no . .Pp See also .Sx VERIFYING HOST KEYS in .Xr ssh 1 . .It Cm VersionAddendum Specifies a string to append to the regular version string to identify OS- or site-specific modifications. The default is .Dq FreeBSD-20220415 . The value .Cm none may be used to disable this. .It Cm VisualHostKey If this flag is set to .Cm yes , an ASCII art representation of the remote host key fingerprint is printed in addition to the fingerprint string at login and for unknown host keys. If this flag is set to .Cm no (the default), no fingerprint strings are printed at login and only the fingerprint string will be printed for unknown host keys. .It Cm XAuthLocation Specifies the full pathname of the .Xr xauth 1 program. The default is .Pa /usr/local/bin/xauth . .El .Sh PATTERNS A .Em pattern consists of zero or more non-whitespace characters, .Sq * (a wildcard that matches zero or more characters), or .Sq ?\& (a wildcard that matches exactly one character). For example, to specify a set of declarations for any host in the .Qq .co.uk set of domains, the following pattern could be used: .Pp .Dl Host *.co.uk .Pp The following pattern would match any host in the 192.168.0.[0-9] network range: .Pp .Dl Host 192.168.0.? .Pp A .Em pattern-list is a comma-separated list of patterns. Patterns within pattern-lists may be negated by preceding them with an exclamation mark .Pq Sq !\& . For example, to allow a key to be used from anywhere within an organization except from the .Qq dialup pool, the following entry (in authorized_keys) could be used: .Pp .Dl from=\&"!*.dialup.example.com,*.example.com\&" .Pp Note that a negated match will never produce a positive result by itself. For example, attempting to match .Qq host3 against the following pattern-list will fail: .Pp .Dl from=\&"!host1,!host2\&" .Pp The solution here is to include a term that will yield a positive match, such as a wildcard: .Pp .Dl from=\&"!host1,!host2,*\&" .Sh TOKENS Arguments to some keywords can make use of tokens, which are expanded at runtime: .Pp .Bl -tag -width XXXX -offset indent -compact .It %% A literal .Sq % . .It \&%C Hash of %l%h%p%r. .It %d Local user's home directory. .It %f The fingerprint of the server's host key. .It %H The .Pa known_hosts hostname or address that is being searched for. .It %h The remote hostname. .It \%%I A string describing the reason for a .Cm KnownHostsCommand execution: either .Cm ADDRESS when looking up a host by address (only when .Cm CheckHostIP is enabled), .Cm HOSTNAME when searching by hostname, or .Cm ORDER when preparing the host key algorithm preference list to use for the destination host. .It %i The local user ID. .It %K The base64 encoded host key. .It %k The host key alias if specified, otherwise the original remote hostname given on the command line. .It %L The local hostname. .It %l The local hostname, including the domain name. .It %n The original remote hostname, as given on the command line. .It %p The remote port. .It %r The remote username. .It \&%T The local .Xr tun 4 or .Xr tap 4 network interface assigned if tunnel forwarding was requested, or .Qq NONE otherwise. .It %t The type of the server host key, e.g. .Cm ssh-ed25519 . .It %u The local username. .El .Pp .Cm CertificateFile , .Cm ControlPath , .Cm IdentityAgent , .Cm IdentityFile , .Cm KnownHostsCommand , .Cm LocalForward , .Cm Match exec , .Cm RemoteCommand , .Cm RemoteForward , and .Cm UserKnownHostsFile accept the tokens %%, %C, %d, %h, %i, %k, %L, %l, %n, %p, %r, and %u. .Pp .Cm KnownHostsCommand additionally accepts the tokens %f, %H, %I, %K and %t. .Pp .Cm Hostname accepts the tokens %% and %h. .Pp .Cm LocalCommand accepts all tokens. .Pp .Cm ProxyCommand and .Cm ProxyJump accept the tokens %%, %h, %n, %p, and %r. .Sh ENVIRONMENT VARIABLES Arguments to some keywords can be expanded at runtime from environment variables on the client by enclosing them in .Ic ${} , for example .Ic ${HOME}/.ssh would refer to the user's .ssh directory. If a specified environment variable does not exist then an error will be returned and the setting for that keyword will be ignored. .Pp The keywords .Cm CertificateFile , .Cm ControlPath , .Cm IdentityAgent , .Cm IdentityFile , .Cm KnownHostsCommand , and .Cm UserKnownHostsFile support environment variables. The keywords .Cm LocalForward and .Cm RemoteForward support environment variables only for Unix domain socket paths. .Sh FILES .Bl -tag -width Ds .It Pa ~/.ssh/config This is the per-user configuration file. The format of this file is described above. This file is used by the SSH client. Because of the potential for abuse, this file must have strict permissions: read/write for the user, and not writable by others. .It Pa /etc/ssh/ssh_config Systemwide configuration file. This file provides defaults for those values that are not specified in the user's configuration file, and for those users who do not have a configuration file. This file must be world-readable. .El .Sh SEE ALSO .Xr ssh 1 .Sh AUTHORS .An -nosplit OpenSSH is a derivative of the original and free ssh 1.2.12 release by .An Tatu Ylonen . .An Aaron Campbell , Bob Beck , Markus Friedl , .An Niels Provos , Theo de Raadt and .An Dug Song removed many bugs, re-added newer features and created OpenSSH. .An Markus Friedl contributed the support for SSH protocol versions 1.5 and 2.0.