1 /* $OpenBSD: auth.c,v 1.127 2018/03/12 00:52:01 djm Exp $ */
3 * Copyright (c) 2000 Markus Friedl. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 #include <sys/types.h>
30 #include <sys/socket.h>
33 #include <netinet/in.h>
56 #include "groupaccess.h"
64 #include "auth-options.h"
73 #include "monitor_wrap.h"
80 extern ServerOptions options;
81 extern int use_privsep;
82 extern Buffer loginmsg;
83 extern struct passwd *privsep_pw;
84 extern struct sshauthopt *auth_opts;
86 /* Debugging messages */
91 * Check if the user is allowed to log in via ssh. If user is listed
92 * in DenyUsers or one of user's groups is listed in DenyGroups, false
93 * will be returned. If AllowUsers isn't empty and user isn't listed
94 * there, or if AllowGroups isn't empty and one of user's groups isn't
95 * listed there, false will be returned.
96 * If the user's shell is not executable, false will be returned.
97 * Otherwise true is returned.
100 allowed_user(struct passwd * pw)
102 struct ssh *ssh = active_state; /* XXX */
104 const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL;
108 struct spwd *spw = NULL;
111 /* Shouldn't be called if pw is NULL, but better safe than sorry... */
112 if (!pw || !pw->pw_name)
116 if (!options.use_pam)
117 spw = getspnam(pw->pw_name);
118 #ifdef HAS_SHADOW_EXPIRE
119 if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
121 #endif /* HAS_SHADOW_EXPIRE */
122 #endif /* USE_SHADOW */
124 /* grab passwd field for locked account check */
125 passwd = pw->pw_passwd;
129 passwd = get_iaf_password(pw);
131 passwd = spw->sp_pwdp;
132 #endif /* USE_LIBIAF */
135 /* check for locked account */
136 if (!options.use_pam && passwd && *passwd) {
139 #ifdef LOCKED_PASSWD_STRING
140 if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
143 #ifdef LOCKED_PASSWD_PREFIX
144 if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
145 strlen(LOCKED_PASSWD_PREFIX)) == 0)
148 #ifdef LOCKED_PASSWD_SUBSTR
149 if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
153 free((void *) passwd);
154 #endif /* USE_LIBIAF */
156 logit("User %.100s not allowed because account is locked",
163 * Deny if shell does not exist or is not executable unless we
166 if (options.chroot_directory == NULL ||
167 strcasecmp(options.chroot_directory, "none") == 0) {
168 char *shell = xstrdup((pw->pw_shell[0] == '\0') ?
169 _PATH_BSHELL : pw->pw_shell); /* empty = /bin/sh */
171 if (stat(shell, &st) != 0) {
172 logit("User %.100s not allowed because shell %.100s "
173 "does not exist", pw->pw_name, shell);
177 if (S_ISREG(st.st_mode) == 0 ||
178 (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) {
179 logit("User %.100s not allowed because shell %.100s "
180 "is not executable", pw->pw_name, shell);
187 if (options.num_deny_users > 0 || options.num_allow_users > 0 ||
188 options.num_deny_groups > 0 || options.num_allow_groups > 0) {
189 hostname = auth_get_canonical_hostname(ssh, options.use_dns);
190 ipaddr = ssh_remote_ipaddr(ssh);
193 /* Return false if user is listed in DenyUsers */
194 if (options.num_deny_users > 0) {
195 for (i = 0; i < options.num_deny_users; i++) {
196 r = match_user(pw->pw_name, hostname, ipaddr,
197 options.deny_users[i]);
199 fatal("Invalid DenyUsers pattern \"%.100s\"",
200 options.deny_users[i]);
202 logit("User %.100s from %.100s not allowed "
203 "because listed in DenyUsers",
204 pw->pw_name, hostname);
209 /* Return false if AllowUsers isn't empty and user isn't listed there */
210 if (options.num_allow_users > 0) {
211 for (i = 0; i < options.num_allow_users; i++) {
212 r = match_user(pw->pw_name, hostname, ipaddr,
213 options.allow_users[i]);
215 fatal("Invalid AllowUsers pattern \"%.100s\"",
216 options.allow_users[i]);
220 /* i < options.num_allow_users iff we break for loop */
221 if (i >= options.num_allow_users) {
222 logit("User %.100s from %.100s not allowed because "
223 "not listed in AllowUsers", pw->pw_name, hostname);
227 if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
228 /* Get the user's group access list (primary and supplementary) */
229 if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
230 logit("User %.100s from %.100s not allowed because "
231 "not in any group", pw->pw_name, hostname);
235 /* Return false if one of user's groups is listed in DenyGroups */
236 if (options.num_deny_groups > 0)
237 if (ga_match(options.deny_groups,
238 options.num_deny_groups)) {
240 logit("User %.100s from %.100s not allowed "
241 "because a group is listed in DenyGroups",
242 pw->pw_name, hostname);
246 * Return false if AllowGroups isn't empty and one of user's groups
249 if (options.num_allow_groups > 0)
250 if (!ga_match(options.allow_groups,
251 options.num_allow_groups)) {
253 logit("User %.100s from %.100s not allowed "
254 "because none of user's groups are listed "
255 "in AllowGroups", pw->pw_name, hostname);
261 #ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
262 if (!sys_auth_allowed_user(pw, &loginmsg))
266 /* We found no reason not to let this user try to log on... */
271 * Formats any key left in authctxt->auth_method_key for inclusion in
272 * auth_log()'s message. Also includes authxtct->auth_method_info if present.
275 format_method_key(Authctxt *authctxt)
277 const struct sshkey *key = authctxt->auth_method_key;
278 const char *methinfo = authctxt->auth_method_info;
279 char *fp, *ret = NULL;
284 if (key_is_cert(key)) {
285 fp = sshkey_fingerprint(key->cert->signature_key,
286 options.fingerprint_hash, SSH_FP_DEFAULT);
287 xasprintf(&ret, "%s ID %s (serial %llu) CA %s %s%s%s",
288 sshkey_type(key), key->cert->key_id,
289 (unsigned long long)key->cert->serial,
290 sshkey_type(key->cert->signature_key),
291 fp == NULL ? "(null)" : fp,
292 methinfo == NULL ? "" : ", ",
293 methinfo == NULL ? "" : methinfo);
296 fp = sshkey_fingerprint(key, options.fingerprint_hash,
298 xasprintf(&ret, "%s %s%s%s", sshkey_type(key),
299 fp == NULL ? "(null)" : fp,
300 methinfo == NULL ? "" : ", ",
301 methinfo == NULL ? "" : methinfo);
308 auth_log(Authctxt *authctxt, int authenticated, int partial,
309 const char *method, const char *submethod)
311 struct ssh *ssh = active_state; /* XXX */
312 void (*authlog) (const char *fmt,...) = verbose;
316 if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
319 /* Raise logging level */
320 if (authenticated == 1 ||
322 authctxt->failures >= options.max_authtries / 2 ||
323 strcmp(method, "password") == 0)
326 if (authctxt->postponed)
327 authmsg = "Postponed";
331 authmsg = authenticated ? "Accepted" : "Failed";
333 if ((extra = format_method_key(authctxt)) == NULL) {
334 if (authctxt->auth_method_info != NULL)
335 extra = xstrdup(authctxt->auth_method_info);
338 authlog("%s %s%s%s for %s%.100s from %.200s port %d ssh2%s%s",
341 submethod != NULL ? "/" : "", submethod == NULL ? "" : submethod,
342 authctxt->valid ? "" : "invalid user ",
344 ssh_remote_ipaddr(ssh),
345 ssh_remote_port(ssh),
346 extra != NULL ? ": " : "",
347 extra != NULL ? extra : "");
351 #ifdef CUSTOM_FAILED_LOGIN
352 if (authenticated == 0 && !authctxt->postponed &&
353 (strcmp(method, "password") == 0 ||
354 strncmp(method, "keyboard-interactive", 20) == 0 ||
355 strcmp(method, "challenge-response") == 0))
356 record_failed_login(authctxt->user,
357 auth_get_canonical_hostname(ssh, options.use_dns), "ssh");
358 # ifdef WITH_AIXAUTHENTICATE
360 sys_auth_record_login(authctxt->user,
361 auth_get_canonical_hostname(ssh, options.use_dns), "ssh",
365 #ifdef SSH_AUDIT_EVENTS
366 if (authenticated == 0 && !authctxt->postponed)
367 audit_event(audit_classify_auth(method));
373 auth_maxtries_exceeded(Authctxt *authctxt)
375 struct ssh *ssh = active_state; /* XXX */
377 error("maximum authentication attempts exceeded for "
378 "%s%.100s from %.200s port %d ssh2",
379 authctxt->valid ? "" : "invalid user ",
381 ssh_remote_ipaddr(ssh),
382 ssh_remote_port(ssh));
383 packet_disconnect("Too many authentication failures");
388 * Check whether root logins are disallowed.
391 auth_root_allowed(struct ssh *ssh, const char *method)
393 switch (options.permit_root_login) {
396 case PERMIT_NO_PASSWD:
397 if (strcmp(method, "publickey") == 0 ||
398 strcmp(method, "hostbased") == 0 ||
399 strcmp(method, "gssapi-with-mic") == 0)
402 case PERMIT_FORCED_ONLY:
403 if (auth_opts->force_command != NULL) {
404 logit("Root login accepted for forced command.");
409 logit("ROOT LOGIN REFUSED FROM %.200s port %d",
410 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
416 * Given a template and a passwd structure, build a filename
417 * by substituting % tokenised options. Currently, %% becomes '%',
418 * %h becomes the home directory and %u the username.
420 * This returns a buffer allocated by xmalloc.
423 expand_authorized_keys(const char *filename, struct passwd *pw)
425 char *file, ret[PATH_MAX];
428 file = percent_expand(filename, "h", pw->pw_dir,
429 "u", pw->pw_name, (char *)NULL);
432 * Ensure that filename starts anchored. If not, be backward
433 * compatible and prepend the '%h/'
438 i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
439 if (i < 0 || (size_t)i >= sizeof(ret))
440 fatal("expand_authorized_keys: path too long");
442 return (xstrdup(ret));
446 authorized_principals_file(struct passwd *pw)
448 if (options.authorized_principals_file == NULL)
450 return expand_authorized_keys(options.authorized_principals_file, pw);
453 /* return ok if key exists in sysfile or userfile */
455 check_key_in_hostfiles(struct passwd *pw, struct sshkey *key, const char *host,
456 const char *sysfile, const char *userfile)
460 HostStatus host_status;
461 struct hostkeys *hostkeys;
462 const struct hostkey_entry *found;
464 hostkeys = init_hostkeys();
465 load_hostkeys(hostkeys, host, sysfile);
466 if (userfile != NULL) {
467 user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
468 if (options.strict_modes &&
469 (stat(user_hostfile, &st) == 0) &&
470 ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
471 (st.st_mode & 022) != 0)) {
472 logit("Authentication refused for %.100s: "
473 "bad owner or modes for %.200s",
474 pw->pw_name, user_hostfile);
475 auth_debug_add("Ignored %.200s: bad ownership or modes",
478 temporarily_use_uid(pw);
479 load_hostkeys(hostkeys, host, user_hostfile);
484 host_status = check_key_in_hostkeys(hostkeys, key, &found);
485 if (host_status == HOST_REVOKED)
486 error("WARNING: revoked key for %s attempted authentication",
488 else if (host_status == HOST_OK)
489 debug("%s: key for %s found at %s:%ld", __func__,
490 found->host, found->file, found->line);
492 debug("%s: key for host %s not found", __func__, host);
494 free_hostkeys(hostkeys);
500 auth_openfile(const char *file, struct passwd *pw, int strict_modes,
501 int log_missing, char *file_type)
508 if ((fd = open(file, O_RDONLY|O_NONBLOCK)) == -1) {
509 if (log_missing || errno != ENOENT)
510 debug("Could not open %s '%s': %s", file_type, file,
515 if (fstat(fd, &st) < 0) {
519 if (!S_ISREG(st.st_mode)) {
520 logit("User %s %s %s is not a regular file",
521 pw->pw_name, file_type, file);
526 if ((f = fdopen(fd, "r")) == NULL) {
531 safe_path_fd(fileno(f), file, pw, line, sizeof(line)) != 0) {
533 logit("Authentication refused: %s", line);
534 auth_debug_add("Ignored %s: %s", file_type, line);
543 auth_openkeyfile(const char *file, struct passwd *pw, int strict_modes)
545 return auth_openfile(file, pw, strict_modes, 1, "authorized keys");
549 auth_openprincipals(const char *file, struct passwd *pw, int strict_modes)
551 return auth_openfile(file, pw, strict_modes, 0,
552 "authorized principals");
556 getpwnamallow(const char *user)
558 struct ssh *ssh = active_state; /* XXX */
559 #ifdef HAVE_LOGIN_CAP
560 extern login_cap_t *lc;
566 struct connection_info *ci = get_connection_info(1, options.use_dns);
569 parse_server_match_config(&options, ci);
570 log_change_level(options.log_level);
571 process_permitopen(ssh, &options);
573 #if defined(_AIX) && defined(HAVE_SETAUTHDB)
579 #if defined(_AIX) && defined(HAVE_SETAUTHDB)
584 * Windows usernames are case-insensitive. To avoid later problems
585 * when trying to match the username, the user is only allowed to
586 * login if the username is given in the same case as stored in the
589 if (pw != NULL && strcmp(user, pw->pw_name) != 0) {
590 logit("Login name %.100s does not match stored username %.100s",
596 logit("Invalid user %.100s from %.100s port %d",
597 user, ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
598 #ifdef CUSTOM_FAILED_LOGIN
599 record_failed_login(user,
600 auth_get_canonical_hostname(ssh, options.use_dns), "ssh");
602 #ifdef SSH_AUDIT_EVENTS
603 audit_event(SSH_INVALID_USER);
604 #endif /* SSH_AUDIT_EVENTS */
607 if (!allowed_user(pw))
609 #ifdef HAVE_LOGIN_CAP
610 if ((lc = login_getclass(pw->pw_class)) == NULL) {
611 debug("unable to get login class: %s", user);
615 if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 ||
616 auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
617 debug("Approval failure for %s", user);
629 /* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */
631 auth_key_is_revoked(struct sshkey *key)
636 if (options.revoked_keys_file == NULL)
638 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash,
639 SSH_FP_DEFAULT)) == NULL) {
640 r = SSH_ERR_ALLOC_FAIL;
641 error("%s: fingerprint key: %s", __func__, ssh_err(r));
645 r = sshkey_check_revoked(key, options.revoked_keys_file);
648 break; /* not revoked */
649 case SSH_ERR_KEY_REVOKED:
650 error("Authentication key %s %s revoked by file %s",
651 sshkey_type(key), fp, options.revoked_keys_file);
654 error("Error checking authentication key %s %s in "
655 "revoked keys file %s: %s", sshkey_type(key), fp,
656 options.revoked_keys_file, ssh_err(r));
665 return r == 0 ? 0 : 1;
669 auth_debug_add(const char *fmt,...)
674 if (!auth_debug_init)
678 vsnprintf(buf, sizeof(buf), fmt, args);
680 buffer_put_cstring(&auth_debug, buf);
684 auth_debug_send(void)
688 if (!auth_debug_init)
690 while (buffer_len(&auth_debug)) {
691 msg = buffer_get_string(&auth_debug, NULL);
692 packet_send_debug("%s", msg);
698 auth_debug_reset(void)
701 buffer_clear(&auth_debug);
703 buffer_init(&auth_debug);
711 static struct passwd fake;
713 memset(&fake, 0, sizeof(fake));
714 fake.pw_name = "NOUSER";
716 "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
717 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS
718 fake.pw_gecos = "NOUSER";
720 fake.pw_uid = privsep_pw == NULL ? (uid_t)-1 : privsep_pw->pw_uid;
721 fake.pw_gid = privsep_pw == NULL ? (gid_t)-1 : privsep_pw->pw_gid;
722 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS
725 fake.pw_dir = "/nonexist";
726 fake.pw_shell = "/nonexist";
732 * Returns the remote DNS hostname as a string. The returned string must not
733 * be freed. NB. this will usually trigger a DNS query the first time it is
735 * This function does additional checks on the hostname to mitigate some
736 * attacks on legacy rhosts-style authentication.
737 * XXX is RhostsRSAAuthentication vulnerable to these?
738 * XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?)
742 remote_hostname(struct ssh *ssh)
744 struct sockaddr_storage from;
746 struct addrinfo hints, *ai, *aitop;
747 char name[NI_MAXHOST], ntop2[NI_MAXHOST];
748 const char *ntop = ssh_remote_ipaddr(ssh);
750 /* Get IP address of client. */
751 fromlen = sizeof(from);
752 memset(&from, 0, sizeof(from));
753 if (getpeername(ssh_packet_get_connection_in(ssh),
754 (struct sockaddr *)&from, &fromlen) < 0) {
755 debug("getpeername failed: %.100s", strerror(errno));
759 ipv64_normalise_mapped(&from, &fromlen);
760 if (from.ss_family == AF_INET6)
761 fromlen = sizeof(struct sockaddr_in6);
763 debug3("Trying to reverse map address %.100s.", ntop);
764 /* Map the IP address to a host name. */
765 if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
766 NULL, 0, NI_NAMEREQD) != 0) {
767 /* Host name not found. Use ip address. */
772 * if reverse lookup result looks like a numeric hostname,
773 * someone is trying to trick us by PTR record like following:
774 * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5
776 memset(&hints, 0, sizeof(hints));
777 hints.ai_socktype = SOCK_DGRAM; /*dummy*/
778 hints.ai_flags = AI_NUMERICHOST;
779 if (getaddrinfo(name, NULL, &hints, &ai) == 0) {
780 logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
786 /* Names are stored in lowercase. */
790 * Map it back to an IP address and check that the given
791 * address actually is an address of this host. This is
792 * necessary because anyone with access to a name server can
793 * define arbitrary names for an IP address. Mapping from
794 * name to IP address can be trusted better (but can still be
795 * fooled if the intruder has access to the name server of
798 memset(&hints, 0, sizeof(hints));
799 hints.ai_family = from.ss_family;
800 hints.ai_socktype = SOCK_STREAM;
801 if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
802 logit("reverse mapping checking getaddrinfo for %.700s "
803 "[%s] failed.", name, ntop);
806 /* Look for the address from the list of addresses. */
807 for (ai = aitop; ai; ai = ai->ai_next) {
808 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
809 sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
810 (strcmp(ntop, ntop2) == 0))
814 /* If we reached the end of the list, the address was not there. */
816 /* Address not found for the host name. */
817 logit("Address %.100s maps to %.600s, but this does not "
818 "map back to the address.", ntop, name);
825 * Return the canonical name of the host in the other side of the current
826 * connection. The host name is cached, so it is efficient to call this
831 auth_get_canonical_hostname(struct ssh *ssh, int use_dns)
833 static char *dnsname;
836 return ssh_remote_ipaddr(ssh);
837 else if (dnsname != NULL)
840 dnsname = remote_hostname(ssh);
846 * Runs command in a subprocess wuth a minimal environment.
847 * Returns pid on success, 0 on failure.
848 * The child stdout and stderr maybe captured, left attached or sent to
849 * /dev/null depending on the contents of flags.
850 * "tag" is prepended to log messages.
851 * NB. "command" is only used for logging; the actual command executed is
855 subprocess(const char *tag, struct passwd *pw, const char *command,
856 int ac, char **av, FILE **child, u_int flags)
860 int fd, devnull, p[2], i;
862 char *cp, errmsg[512];
869 debug3("%s: %s command \"%s\" running as %s (flags 0x%x)", __func__,
870 tag, command, pw->pw_name, flags);
872 /* Check consistency */
873 if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 &&
874 (flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0) {
875 error("%s: inconsistent flags", __func__);
878 if (((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0) != (child == NULL)) {
879 error("%s: inconsistent flags/output", __func__);
884 * If executing an explicit binary, then verify the it exists
885 * and appears safe-ish to execute
888 error("%s path is not absolute", tag);
891 temporarily_use_uid(pw);
892 if (stat(av[0], &st) < 0) {
893 error("Could not stat %s \"%s\": %s", tag,
894 av[0], strerror(errno));
898 if (safe_path(av[0], &st, NULL, 0, errmsg, sizeof(errmsg)) != 0) {
899 error("Unsafe %s \"%s\": %s", tag, av[0], errmsg);
903 /* Prepare to keep the child's stdout if requested */
905 error("%s: pipe: %s", tag, strerror(errno));
911 switch ((pid = fork())) {
913 error("%s: fork: %s", tag, strerror(errno));
918 /* Prepare a minimal environment for the child. */
920 child_env = xcalloc(sizeof(*child_env), envsize);
921 child_set_env(&child_env, &envsize, "PATH", _PATH_STDPATH);
922 child_set_env(&child_env, &envsize, "USER", pw->pw_name);
923 child_set_env(&child_env, &envsize, "LOGNAME", pw->pw_name);
924 child_set_env(&child_env, &envsize, "HOME", pw->pw_dir);
925 if ((cp = getenv("LANG")) != NULL)
926 child_set_env(&child_env, &envsize, "LANG", cp);
928 for (i = 0; i < NSIG; i++)
931 if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
932 error("%s: open %s: %s", tag, _PATH_DEVNULL,
936 if (dup2(devnull, STDIN_FILENO) == -1) {
937 error("%s: dup2: %s", tag, strerror(errno));
941 /* Set up stdout as requested; leave stderr in place for now. */
943 if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0)
945 else if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0)
947 if (fd != -1 && dup2(fd, STDOUT_FILENO) == -1) {
948 error("%s: dup2: %s", tag, strerror(errno));
951 closefrom(STDERR_FILENO + 1);
953 /* Don't use permanently_set_uid() here to avoid fatal() */
954 if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) != 0) {
955 error("%s: setresgid %u: %s", tag, (u_int)pw->pw_gid,
959 if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) != 0) {
960 error("%s: setresuid %u: %s", tag, (u_int)pw->pw_uid,
964 /* stdin is pointed to /dev/null at this point */
965 if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 &&
966 dup2(STDIN_FILENO, STDERR_FILENO) == -1) {
967 error("%s: dup2: %s", tag, strerror(errno));
971 execve(av[0], av, child_env);
972 error("%s exec \"%s\": %s", tag, command, strerror(errno));
974 default: /* parent */
979 if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0)
981 else if ((f = fdopen(p[0], "r")) == NULL) {
982 error("%s: fdopen: %s", tag, strerror(errno));
984 /* Don't leave zombie child */
986 while (waitpid(pid, NULL, 0) == -1 && errno == EINTR)
991 debug3("%s: %s pid %ld", __func__, tag, (long)pid);
997 /* These functions link key/cert options to the auth framework */
999 /* Log sshauthopt options locally and (optionally) for remote transmission */
1001 auth_log_authopts(const char *loc, const struct sshauthopt *opts, int do_remote)
1003 int do_env = options.permit_user_env && opts->nenv > 0;
1004 int do_permitopen = opts->npermitopen > 0 &&
1005 (options.allow_tcp_forwarding & FORWARD_LOCAL) != 0;
1007 char msg[1024], buf[64];
1009 snprintf(buf, sizeof(buf), "%d", opts->force_tun_device);
1010 /* Try to keep this alphabetically sorted */
1011 snprintf(msg, sizeof(msg), "key options:%s%s%s%s%s%s%s%s%s%s%s%s",
1012 opts->permit_agent_forwarding_flag ? " agent-forwarding" : "",
1013 opts->force_command == NULL ? "" : " command",
1014 do_env ? " environment" : "",
1015 opts->valid_before == 0 ? "" : "expires",
1016 do_permitopen ? " permitopen" : "",
1017 opts->permit_port_forwarding_flag ? " port-forwarding" : "",
1018 opts->cert_principals == NULL ? "" : " principals",
1019 opts->permit_pty_flag ? " pty" : "",
1020 opts->force_tun_device == -1 ? "" : " tun=",
1021 opts->force_tun_device == -1 ? "" : buf,
1022 opts->permit_user_rc ? " user-rc" : "",
1023 opts->permit_x11_forwarding_flag ? " x11-forwarding" : "");
1025 debug("%s: %s", loc, msg);
1027 auth_debug_add("%s: %s", loc, msg);
1029 if (options.permit_user_env) {
1030 for (i = 0; i < opts->nenv; i++) {
1031 debug("%s: environment: %s", loc, opts->env[i]);
1033 auth_debug_add("%s: environment: %s",
1039 /* Go into a little more details for the local logs. */
1040 if (opts->valid_before != 0) {
1041 format_absolute_time(opts->valid_before, buf, sizeof(buf));
1042 debug("%s: expires at %s", loc, buf);
1044 if (opts->cert_principals != NULL) {
1045 debug("%s: authorized principals: \"%s\"",
1046 loc, opts->cert_principals);
1048 if (opts->force_command != NULL)
1049 debug("%s: forced command: \"%s\"", loc, opts->force_command);
1050 if ((options.allow_tcp_forwarding & FORWARD_LOCAL) != 0) {
1051 for (i = 0; i < opts->npermitopen; i++) {
1052 debug("%s: permitted open: %s",
1053 loc, opts->permitopen[i]);
1058 /* Activate a new set of key/cert options; merging with what is there. */
1060 auth_activate_options(struct ssh *ssh, struct sshauthopt *opts)
1062 struct sshauthopt *old = auth_opts;
1063 const char *emsg = NULL;
1065 debug("%s: setting new authentication options", __func__);
1066 if ((auth_opts = sshauthopt_merge(old, opts, &emsg)) == NULL) {
1067 error("Inconsistent authentication options: %s", emsg);
1073 /* Disable forwarding, etc for the session */
1075 auth_restrict_session(struct ssh *ssh)
1077 struct sshauthopt *restricted;
1079 debug("%s: restricting session", __func__);
1081 /* A blank sshauthopt defaults to permitting nothing */
1082 restricted = sshauthopt_new();
1083 restricted->restricted = 1;
1085 if (auth_activate_options(ssh, restricted) != 0)
1086 fatal("%s: failed to restrict session", __func__);
1087 sshauthopt_free(restricted);
1091 auth_authorise_keyopts(struct ssh *ssh, struct passwd *pw,
1092 struct sshauthopt *opts, int allow_cert_authority, const char *loc)
1094 const char *remote_ip = ssh_remote_ipaddr(ssh);
1095 const char *remote_host = auth_get_canonical_hostname(ssh,
1097 time_t now = time(NULL);
1101 * Check keys/principals file expiry time.
1102 * NB. validity interval in certificate is handled elsewhere.
1104 if (opts->valid_before && now > 0 &&
1105 opts->valid_before < (uint64_t)now) {
1106 format_absolute_time(opts->valid_before, buf, sizeof(buf));
1107 debug("%s: entry expired at %s", loc, buf);
1108 auth_debug_add("%s: entry expired at %s", loc, buf);
1111 /* Consistency checks */
1112 if (opts->cert_principals != NULL && !opts->cert_authority) {
1113 debug("%s: principals on non-CA key", loc);
1114 auth_debug_add("%s: principals on non-CA key", loc);
1118 /* cert-authority flag isn't valid in authorized_principals files */
1119 if (!allow_cert_authority && opts->cert_authority) {
1120 debug("%s: cert-authority flag invalid here", loc);
1121 auth_debug_add("%s: cert-authority flag invalid here", loc);
1126 /* Perform from= checks */
1127 if (opts->required_from_host_keys != NULL) {
1128 switch (match_host_and_ip(remote_host, remote_ip,
1129 opts->required_from_host_keys )) {
1131 /* Host name matches. */
1135 debug("%s: invalid from criteria", loc);
1136 auth_debug_add("%s: invalid from criteria", loc);
1139 logit("%s: Authentication tried for %.100s with "
1140 "correct key but not from a permitted "
1141 "host (host=%.200s, ip=%.200s, required=%.200s).",
1142 loc, pw->pw_name, remote_host, remote_ip,
1143 opts->required_from_host_keys);
1144 auth_debug_add("%s: Your host '%.200s' is not "
1145 "permitted to use this key for login.",
1151 /* Check source-address restriction from certificate */
1152 if (opts->required_from_host_cert != NULL) {
1153 switch (addr_match_cidr_list(remote_ip,
1154 opts->required_from_host_cert)) {
1161 error("%s: Certificate source-address invalid",
1165 logit("%s: Authentication tried for %.100s with valid "
1166 "certificate but not from a permitted source "
1167 "address (%.200s).", loc, pw->pw_name, remote_ip);
1168 auth_debug_add("%s: Your address '%.200s' is not "
1169 "permitted to use this certificate for login.",
1176 * XXX this is spammy. We should report remotely only for keys
1177 * that are successful in actual auth attempts, and not PK_OK
1180 auth_log_authopts(loc, opts, 1);