1 /* $OpenBSD: ssh-agent.c,v 1.155 2007/03/19 12:16:42 dtucker Exp $ */
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * The authentication agent program.
8 * As far as I am concerned, the code I have written for this software
9 * can be used freely for any purpose. Any derived versions of this
10 * software must be clearly marked as such, and if the derived work is
11 * incompatible with the protocol description in the RFC file, it must be
12 * called by a name other than "ssh" or "Secure Shell".
14 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
16 * Redistribution and use in source and binary forms, with or without
17 * modification, are permitted provided that the following conditions
19 * 1. Redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer.
21 * 2. Redistributions in binary form must reproduce the above copyright
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution.
25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
26 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
27 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
28 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
29 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
30 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
31 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 #include <sys/types.h>
40 #include <sys/param.h>
41 #include <sys/resource.h>
43 #include <sys/socket.h>
44 #ifdef HAVE_SYS_TIME_H
45 # include <sys/time.h>
50 #include "openbsd-compat/sys-queue.h"
52 #include <openssl/evp.h>
53 #include <openssl/md5.h>
82 #if defined(HAVE_SYS_PRCTL_H)
83 #include <sys/prctl.h> /* For prctl() and PR_SET_DUMPABLE */
100 u_int sockets_alloc = 0;
101 SocketEntry *sockets = NULL;
103 typedef struct identity {
104 TAILQ_ENTRY(identity) next;
113 TAILQ_HEAD(idqueue, identity) idlist;
116 /* private key table, one per protocol version */
121 /* pid of shell == parent of agent */
122 pid_t parent_pid = -1;
123 u_int parent_alive_interval = 0;
125 /* pathname and directory for AUTH_SOCKET */
126 char socket_name[MAXPATHLEN];
127 char socket_dir[MAXPATHLEN];
131 char *lock_passwd = NULL;
133 extern char *__progname;
135 /* Default lifetime (0 == forever) */
136 static int lifetime = 0;
139 close_socket(SocketEntry *e)
143 e->type = AUTH_UNUSED;
144 buffer_free(&e->input);
145 buffer_free(&e->output);
146 buffer_free(&e->request);
154 for (i = 0; i <=2; i++) {
155 TAILQ_INIT(&idtable[i].idlist);
156 idtable[i].nentries = 0;
160 /* return private key table for requested protocol version */
162 idtab_lookup(int version)
164 if (version < 1 || version > 2)
165 fatal("internal error, bad protocol version %d", version);
166 return &idtable[version];
170 free_identity(Identity *id)
177 /* return matching private key for given public key */
179 lookup_identity(Key *key, int version)
183 Idtab *tab = idtab_lookup(version);
184 TAILQ_FOREACH(id, &tab->idlist, next) {
185 if (key_equal(key, id->key))
191 /* Check confirmation of keysign request */
193 confirm_key(Identity *id)
198 p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX);
199 if (ask_permission("Allow use of key %s?\nKey fingerprint %s.",
207 /* send list of supported public keys to 'client' */
209 process_request_identities(SocketEntry *e, int version)
211 Idtab *tab = idtab_lookup(version);
216 buffer_put_char(&msg, (version == 1) ?
217 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
218 buffer_put_int(&msg, tab->nentries);
219 TAILQ_FOREACH(id, &tab->idlist, next) {
220 if (id->key->type == KEY_RSA1) {
221 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n));
222 buffer_put_bignum(&msg, id->key->rsa->e);
223 buffer_put_bignum(&msg, id->key->rsa->n);
227 key_to_blob(id->key, &blob, &blen);
228 buffer_put_string(&msg, blob, blen);
231 buffer_put_cstring(&msg, id->comment);
233 buffer_put_int(&e->output, buffer_len(&msg));
234 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
240 process_authentication_challenge1(SocketEntry *e)
242 u_char buf[32], mdbuf[16], session_id[16];
252 key = key_new(KEY_RSA1);
253 if ((challenge = BN_new()) == NULL)
254 fatal("process_authentication_challenge1: BN_new failed");
256 (void) buffer_get_int(&e->request); /* ignored */
257 buffer_get_bignum(&e->request, key->rsa->e);
258 buffer_get_bignum(&e->request, key->rsa->n);
259 buffer_get_bignum(&e->request, challenge);
261 /* Only protocol 1.1 is supported */
262 if (buffer_len(&e->request) == 0)
264 buffer_get(&e->request, session_id, 16);
265 response_type = buffer_get_int(&e->request);
266 if (response_type != 1)
269 id = lookup_identity(key, 1);
270 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) {
271 Key *private = id->key;
272 /* Decrypt the challenge using the private key. */
273 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0)
276 /* The response is MD5 of decrypted challenge plus session id. */
277 len = BN_num_bytes(challenge);
278 if (len <= 0 || len > 32) {
279 logit("process_authentication_challenge: bad challenge length %d", len);
283 BN_bn2bin(challenge, buf + 32 - len);
285 MD5_Update(&md, buf, 32);
286 MD5_Update(&md, session_id, 16);
287 MD5_Final(mdbuf, &md);
289 /* Send the response. */
290 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE);
291 for (i = 0; i < 16; i++)
292 buffer_put_char(&msg, mdbuf[i]);
297 /* Unknown identity or protocol error. Send failure. */
298 buffer_put_char(&msg, SSH_AGENT_FAILURE);
300 buffer_put_int(&e->output, buffer_len(&msg));
301 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
303 BN_clear_free(challenge);
309 process_sign_request2(SocketEntry *e)
311 u_char *blob, *data, *signature = NULL;
312 u_int blen, dlen, slen = 0;
313 extern int datafellows;
320 blob = buffer_get_string(&e->request, &blen);
321 data = buffer_get_string(&e->request, &dlen);
323 flags = buffer_get_int(&e->request);
324 if (flags & SSH_AGENT_OLD_SIGNATURE)
325 datafellows = SSH_BUG_SIGBLOB;
327 key = key_from_blob(blob, blen);
329 Identity *id = lookup_identity(key, 2);
330 if (id != NULL && (!id->confirm || confirm_key(id) == 0))
331 ok = key_sign(id->key, &signature, &slen, data, dlen);
336 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE);
337 buffer_put_string(&msg, signature, slen);
339 buffer_put_char(&msg, SSH_AGENT_FAILURE);
341 buffer_put_int(&e->output, buffer_len(&msg));
342 buffer_append(&e->output, buffer_ptr(&msg),
347 if (signature != NULL)
353 process_remove_identity(SocketEntry *e, int version)
362 key = key_new(KEY_RSA1);
363 bits = buffer_get_int(&e->request);
364 buffer_get_bignum(&e->request, key->rsa->e);
365 buffer_get_bignum(&e->request, key->rsa->n);
367 if (bits != key_size(key))
368 logit("Warning: identity keysize mismatch: actual %u, announced %u",
369 key_size(key), bits);
372 blob = buffer_get_string(&e->request, &blen);
373 key = key_from_blob(blob, blen);
378 Identity *id = lookup_identity(key, version);
381 * We have this key. Free the old key. Since we
382 * don't want to leave empty slots in the middle of
383 * the array, we actually free the key there and move
384 * all the entries between the empty slot and the end
387 Idtab *tab = idtab_lookup(version);
388 if (tab->nentries < 1)
389 fatal("process_remove_identity: "
390 "internal error: tab->nentries %d",
392 TAILQ_REMOVE(&tab->idlist, id, next);
399 buffer_put_int(&e->output, 1);
400 buffer_put_char(&e->output,
401 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
405 process_remove_all_identities(SocketEntry *e, int version)
407 Idtab *tab = idtab_lookup(version);
410 /* Loop over all identities and clear the keys. */
411 for (id = TAILQ_FIRST(&tab->idlist); id;
412 id = TAILQ_FIRST(&tab->idlist)) {
413 TAILQ_REMOVE(&tab->idlist, id, next);
417 /* Mark that there are no identities. */
421 buffer_put_int(&e->output, 1);
422 buffer_put_char(&e->output, SSH_AGENT_SUCCESS);
425 /* removes expired keys and returns number of seconds until the next expiry */
429 u_int deadline = 0, now = time(NULL);
434 for (version = 1; version < 3; version++) {
435 tab = idtab_lookup(version);
436 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) {
437 nxt = TAILQ_NEXT(id, next);
440 if (now >= id->death) {
441 debug("expiring key '%s'", id->comment);
442 TAILQ_REMOVE(&tab->idlist, id, next);
446 deadline = (deadline == 0) ? id->death :
447 MIN(deadline, id->death);
450 if (deadline == 0 || deadline <= now)
453 return (deadline - now);
457 process_add_identity(SocketEntry *e, int version)
459 Idtab *tab = idtab_lookup(version);
460 int type, success = 0, death = 0, confirm = 0;
461 char *type_name, *comment;
466 k = key_new_private(KEY_RSA1);
467 (void) buffer_get_int(&e->request); /* ignored */
468 buffer_get_bignum(&e->request, k->rsa->n);
469 buffer_get_bignum(&e->request, k->rsa->e);
470 buffer_get_bignum(&e->request, k->rsa->d);
471 buffer_get_bignum(&e->request, k->rsa->iqmp);
473 /* SSH and SSL have p and q swapped */
474 buffer_get_bignum(&e->request, k->rsa->q); /* p */
475 buffer_get_bignum(&e->request, k->rsa->p); /* q */
477 /* Generate additional parameters */
478 rsa_generate_additional_parameters(k->rsa);
481 type_name = buffer_get_string(&e->request, NULL);
482 type = key_type_from_name(type_name);
486 k = key_new_private(type);
487 buffer_get_bignum2(&e->request, k->dsa->p);
488 buffer_get_bignum2(&e->request, k->dsa->q);
489 buffer_get_bignum2(&e->request, k->dsa->g);
490 buffer_get_bignum2(&e->request, k->dsa->pub_key);
491 buffer_get_bignum2(&e->request, k->dsa->priv_key);
494 k = key_new_private(type);
495 buffer_get_bignum2(&e->request, k->rsa->n);
496 buffer_get_bignum2(&e->request, k->rsa->e);
497 buffer_get_bignum2(&e->request, k->rsa->d);
498 buffer_get_bignum2(&e->request, k->rsa->iqmp);
499 buffer_get_bignum2(&e->request, k->rsa->p);
500 buffer_get_bignum2(&e->request, k->rsa->q);
502 /* Generate additional parameters */
503 rsa_generate_additional_parameters(k->rsa);
506 buffer_clear(&e->request);
511 /* enable blinding */
515 if (RSA_blinding_on(k->rsa, NULL) != 1) {
516 error("process_add_identity: RSA_blinding_on failed");
522 comment = buffer_get_string(&e->request, NULL);
528 while (buffer_len(&e->request)) {
529 switch (buffer_get_char(&e->request)) {
530 case SSH_AGENT_CONSTRAIN_LIFETIME:
531 death = time(NULL) + buffer_get_int(&e->request);
533 case SSH_AGENT_CONSTRAIN_CONFIRM:
540 if (lifetime && !death)
541 death = time(NULL) + lifetime;
542 if (lookup_identity(k, version) == NULL) {
543 Identity *id = xmalloc(sizeof(Identity));
545 id->comment = comment;
547 id->confirm = confirm;
548 TAILQ_INSERT_TAIL(&tab->idlist, id, next);
549 /* Increment the number of identities. */
556 buffer_put_int(&e->output, 1);
557 buffer_put_char(&e->output,
558 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
561 /* XXX todo: encrypt sensitive data with passphrase */
563 process_lock_agent(SocketEntry *e, int lock)
568 passwd = buffer_get_string(&e->request, NULL);
569 if (locked && !lock && strcmp(passwd, lock_passwd) == 0) {
571 memset(lock_passwd, 0, strlen(lock_passwd));
575 } else if (!locked && lock) {
577 lock_passwd = xstrdup(passwd);
580 memset(passwd, 0, strlen(passwd));
583 buffer_put_int(&e->output, 1);
584 buffer_put_char(&e->output,
585 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
589 no_identities(SocketEntry *e, u_int type)
594 buffer_put_char(&msg,
595 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ?
596 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
597 buffer_put_int(&msg, 0);
598 buffer_put_int(&e->output, buffer_len(&msg));
599 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
605 process_add_smartcard_key (SocketEntry *e)
607 char *sc_reader_id = NULL, *pin;
608 int i, version, success = 0, death = 0, confirm = 0;
613 sc_reader_id = buffer_get_string(&e->request, NULL);
614 pin = buffer_get_string(&e->request, NULL);
616 while (buffer_len(&e->request)) {
617 switch (buffer_get_char(&e->request)) {
618 case SSH_AGENT_CONSTRAIN_LIFETIME:
619 death = time(NULL) + buffer_get_int(&e->request);
621 case SSH_AGENT_CONSTRAIN_CONFIRM:
628 if (lifetime && !death)
629 death = time(NULL) + lifetime;
631 keys = sc_get_keys(sc_reader_id, pin);
635 if (keys == NULL || keys[0] == NULL) {
636 error("sc_get_keys failed");
639 for (i = 0; keys[i] != NULL; i++) {
641 version = k->type == KEY_RSA1 ? 1 : 2;
642 tab = idtab_lookup(version);
643 if (lookup_identity(k, version) == NULL) {
644 id = xmalloc(sizeof(Identity));
646 id->comment = sc_get_key_label(k);
648 id->confirm = confirm;
649 TAILQ_INSERT_TAIL(&tab->idlist, id, next);
659 buffer_put_int(&e->output, 1);
660 buffer_put_char(&e->output,
661 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
665 process_remove_smartcard_key(SocketEntry *e)
667 char *sc_reader_id = NULL, *pin;
668 int i, version, success = 0;
669 Key **keys, *k = NULL;
673 sc_reader_id = buffer_get_string(&e->request, NULL);
674 pin = buffer_get_string(&e->request, NULL);
675 keys = sc_get_keys(sc_reader_id, pin);
679 if (keys == NULL || keys[0] == NULL) {
680 error("sc_get_keys failed");
683 for (i = 0; keys[i] != NULL; i++) {
685 version = k->type == KEY_RSA1 ? 1 : 2;
686 if ((id = lookup_identity(k, version)) != NULL) {
687 tab = idtab_lookup(version);
688 TAILQ_REMOVE(&tab->idlist, id, next);
698 buffer_put_int(&e->output, 1);
699 buffer_put_char(&e->output,
700 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
702 #endif /* SMARTCARD */
704 /* dispatch incoming messages */
707 process_message(SocketEntry *e)
712 if (buffer_len(&e->input) < 5)
713 return; /* Incomplete message. */
714 cp = buffer_ptr(&e->input);
715 msg_len = get_u32(cp);
716 if (msg_len > 256 * 1024) {
720 if (buffer_len(&e->input) < msg_len + 4)
723 /* move the current input to e->request */
724 buffer_consume(&e->input, 4);
725 buffer_clear(&e->request);
726 buffer_append(&e->request, buffer_ptr(&e->input), msg_len);
727 buffer_consume(&e->input, msg_len);
728 type = buffer_get_char(&e->request);
730 /* check wheter agent is locked */
731 if (locked && type != SSH_AGENTC_UNLOCK) {
732 buffer_clear(&e->request);
734 case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
735 case SSH2_AGENTC_REQUEST_IDENTITIES:
736 /* send empty lists */
737 no_identities(e, type);
740 /* send a fail message for all other request types */
741 buffer_put_int(&e->output, 1);
742 buffer_put_char(&e->output, SSH_AGENT_FAILURE);
747 debug("type %d", type);
749 case SSH_AGENTC_LOCK:
750 case SSH_AGENTC_UNLOCK:
751 process_lock_agent(e, type == SSH_AGENTC_LOCK);
754 case SSH_AGENTC_RSA_CHALLENGE:
755 process_authentication_challenge1(e);
757 case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
758 process_request_identities(e, 1);
760 case SSH_AGENTC_ADD_RSA_IDENTITY:
761 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED:
762 process_add_identity(e, 1);
764 case SSH_AGENTC_REMOVE_RSA_IDENTITY:
765 process_remove_identity(e, 1);
767 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
768 process_remove_all_identities(e, 1);
771 case SSH2_AGENTC_SIGN_REQUEST:
772 process_sign_request2(e);
774 case SSH2_AGENTC_REQUEST_IDENTITIES:
775 process_request_identities(e, 2);
777 case SSH2_AGENTC_ADD_IDENTITY:
778 case SSH2_AGENTC_ADD_ID_CONSTRAINED:
779 process_add_identity(e, 2);
781 case SSH2_AGENTC_REMOVE_IDENTITY:
782 process_remove_identity(e, 2);
784 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
785 process_remove_all_identities(e, 2);
788 case SSH_AGENTC_ADD_SMARTCARD_KEY:
789 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED:
790 process_add_smartcard_key(e);
792 case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
793 process_remove_smartcard_key(e);
795 #endif /* SMARTCARD */
797 /* Unknown message. Respond with failure. */
798 error("Unknown message %d", type);
799 buffer_clear(&e->request);
800 buffer_put_int(&e->output, 1);
801 buffer_put_char(&e->output, SSH_AGENT_FAILURE);
807 new_socket(sock_type type, int fd)
809 u_int i, old_alloc, new_alloc;
816 for (i = 0; i < sockets_alloc; i++)
817 if (sockets[i].type == AUTH_UNUSED) {
819 buffer_init(&sockets[i].input);
820 buffer_init(&sockets[i].output);
821 buffer_init(&sockets[i].request);
822 sockets[i].type = type;
825 old_alloc = sockets_alloc;
826 new_alloc = sockets_alloc + 10;
827 sockets = xrealloc(sockets, new_alloc, sizeof(sockets[0]));
828 for (i = old_alloc; i < new_alloc; i++)
829 sockets[i].type = AUTH_UNUSED;
830 sockets_alloc = new_alloc;
831 sockets[old_alloc].fd = fd;
832 buffer_init(&sockets[old_alloc].input);
833 buffer_init(&sockets[old_alloc].output);
834 buffer_init(&sockets[old_alloc].request);
835 sockets[old_alloc].type = type;
839 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp,
840 struct timeval **tvpp)
842 u_int i, sz, deadline;
844 static struct timeval tv;
846 for (i = 0; i < sockets_alloc; i++) {
847 switch (sockets[i].type) {
849 case AUTH_CONNECTION:
850 n = MAX(n, sockets[i].fd);
855 fatal("Unknown socket type %d", sockets[i].type);
860 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
861 if (*fdrp == NULL || sz > *nallocp) {
871 debug("XXX shrink: %d < %d", n, *fdl);
873 memset(*fdrp, 0, sz);
874 memset(*fdwp, 0, sz);
876 for (i = 0; i < sockets_alloc; i++) {
877 switch (sockets[i].type) {
879 case AUTH_CONNECTION:
880 FD_SET(sockets[i].fd, *fdrp);
881 if (buffer_len(&sockets[i].output) > 0)
882 FD_SET(sockets[i].fd, *fdwp);
889 if (parent_alive_interval != 0)
890 deadline = (deadline == 0) ? parent_alive_interval :
891 MIN(deadline, parent_alive_interval);
895 tv.tv_sec = deadline;
903 after_select(fd_set *readset, fd_set *writeset)
905 struct sockaddr_un sunaddr;
913 for (i = 0; i < sockets_alloc; i++)
914 switch (sockets[i].type) {
918 if (FD_ISSET(sockets[i].fd, readset)) {
919 slen = sizeof(sunaddr);
920 sock = accept(sockets[i].fd,
921 (struct sockaddr *)&sunaddr, &slen);
923 error("accept from AUTH_SOCKET: %s",
927 if (getpeereid(sock, &euid, &egid) < 0) {
928 error("getpeereid %d failed: %s",
929 sock, strerror(errno));
933 if ((euid != 0) && (getuid() != euid)) {
934 error("uid mismatch: "
935 "peer euid %u != uid %u",
936 (u_int) euid, (u_int) getuid());
940 new_socket(AUTH_CONNECTION, sock);
943 case AUTH_CONNECTION:
944 if (buffer_len(&sockets[i].output) > 0 &&
945 FD_ISSET(sockets[i].fd, writeset)) {
947 len = write(sockets[i].fd,
948 buffer_ptr(&sockets[i].output),
949 buffer_len(&sockets[i].output));
950 if (len == -1 && (errno == EAGAIN ||
956 close_socket(&sockets[i]);
959 buffer_consume(&sockets[i].output, len);
961 if (FD_ISSET(sockets[i].fd, readset)) {
963 len = read(sockets[i].fd, buf, sizeof(buf));
964 if (len == -1 && (errno == EAGAIN ||
970 close_socket(&sockets[i]);
973 buffer_append(&sockets[i].input, buf, len);
974 process_message(&sockets[i]);
978 fatal("Unknown type %d", sockets[i].type);
1000 cleanup_handler(int sig)
1007 check_parent_exists(void)
1009 if (parent_pid != -1 && kill(parent_pid, 0) < 0) {
1010 /* printf("Parent has died - Authentication agent exiting.\n"); */
1019 fprintf(stderr, "Usage: %s [options] [command [args ...]]\n",
1021 fprintf(stderr, "Options:\n");
1022 fprintf(stderr, " -c Generate C-shell commands on stdout.\n");
1023 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n");
1024 fprintf(stderr, " -k Kill the current agent.\n");
1025 fprintf(stderr, " -d Debug mode.\n");
1026 fprintf(stderr, " -a socket Bind agent socket to given name.\n");
1027 fprintf(stderr, " -t life Default identity lifetime (seconds).\n");
1032 main(int ac, char **av)
1034 int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0;
1035 int sock, fd, ch, result, saved_errno;
1037 char *shell, *format, *pidstr, *agentsocket = NULL;
1038 fd_set *readsetp = NULL, *writesetp = NULL;
1039 struct sockaddr_un sunaddr;
1040 #ifdef HAVE_SETRLIMIT
1045 extern char *optarg;
1047 char pidstrbuf[1 + 3 * sizeof pid];
1048 struct timeval *tvp = NULL;
1050 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1057 #if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE)
1058 /* Disable ptrace on Linux without sgid bit */
1059 prctl(PR_SET_DUMPABLE, 0);
1062 SSLeay_add_all_algorithms();
1064 __progname = ssh_get_progname(av[0]);
1068 while ((ch = getopt(ac, av, "cdksa:t:")) != -1) {
1089 agentsocket = optarg;
1092 if ((lifetime = convtime(optarg)) == -1) {
1093 fprintf(stderr, "Invalid lifetime\n");
1104 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag))
1107 if (ac == 0 && !c_flag && !s_flag) {
1108 shell = getenv("SHELL");
1109 if (shell != NULL &&
1110 strncmp(shell + strlen(shell) - 3, "csh", 3) == 0)
1114 const char *errstr = NULL;
1116 pidstr = getenv(SSH_AGENTPID_ENV_NAME);
1117 if (pidstr == NULL) {
1118 fprintf(stderr, "%s not set, cannot kill agent\n",
1119 SSH_AGENTPID_ENV_NAME);
1122 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr);
1125 "%s=\"%s\", which is not a good PID: %s\n",
1126 SSH_AGENTPID_ENV_NAME, pidstr, errstr);
1129 if (kill(pid, SIGTERM) == -1) {
1133 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
1134 printf(format, SSH_AUTHSOCKET_ENV_NAME);
1135 printf(format, SSH_AGENTPID_ENV_NAME);
1136 printf("echo Agent pid %ld killed;\n", (long)pid);
1139 parent_pid = getpid();
1141 if (agentsocket == NULL) {
1142 /* Create private directory for agent socket */
1143 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXXXX", sizeof socket_dir);
1144 if (mkdtemp(socket_dir) == NULL) {
1145 perror("mkdtemp: private socket dir");
1148 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir,
1151 /* Try to use specified agent socket */
1152 socket_dir[0] = '\0';
1153 strlcpy(socket_name, agentsocket, sizeof socket_name);
1157 * Create socket early so it will exist before command gets run from
1160 sock = socket(AF_UNIX, SOCK_STREAM, 0);
1163 *socket_name = '\0'; /* Don't unlink any existing file */
1166 memset(&sunaddr, 0, sizeof(sunaddr));
1167 sunaddr.sun_family = AF_UNIX;
1168 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path));
1169 prev_mask = umask(0177);
1170 if (bind(sock, (struct sockaddr *) &sunaddr, sizeof(sunaddr)) < 0) {
1172 *socket_name = '\0'; /* Don't unlink any existing file */
1177 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
1183 * Fork, and have the parent execute the command, if any, or present
1184 * the socket data. The child continues as the authentication agent.
1187 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1);
1188 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1189 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1190 SSH_AUTHSOCKET_ENV_NAME);
1191 printf("echo Agent pid %ld;\n", (long)parent_pid);
1199 if (pid != 0) { /* Parent - execute the given command. */
1201 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid);
1203 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1204 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1205 SSH_AUTHSOCKET_ENV_NAME);
1206 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
1207 SSH_AGENTPID_ENV_NAME);
1208 printf("echo Agent pid %ld;\n", (long)pid);
1211 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 ||
1212 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) {
1221 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0);
1223 if (setsid() == -1) {
1224 error("setsid: %s", strerror(errno));
1229 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1230 /* XXX might close listen socket */
1231 (void)dup2(fd, STDIN_FILENO);
1232 (void)dup2(fd, STDOUT_FILENO);
1233 (void)dup2(fd, STDERR_FILENO);
1238 #ifdef HAVE_SETRLIMIT
1239 /* deny core dumps, since memory contains unencrypted private keys */
1240 rlim.rlim_cur = rlim.rlim_max = 0;
1241 if (setrlimit(RLIMIT_CORE, &rlim) < 0) {
1242 error("setrlimit RLIMIT_CORE: %s", strerror(errno));
1248 new_socket(AUTH_SOCKET, sock);
1250 parent_alive_interval = 10;
1253 signal(SIGINT, SIG_IGN);
1254 signal(SIGPIPE, SIG_IGN);
1255 signal(SIGHUP, cleanup_handler);
1256 signal(SIGTERM, cleanup_handler);
1260 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp);
1261 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp);
1262 saved_errno = errno;
1263 if (parent_alive_interval != 0)
1264 check_parent_exists();
1265 (void) reaper(); /* remove expired keys */
1267 if (saved_errno == EINTR)
1269 fatal("select: %s", strerror(saved_errno));
1270 } else if (result > 0)
1271 after_select(readsetp, writesetp);