1 /* $OpenBSD: ssh-agent.c,v 1.158 2008/06/28 13:58:23 djm 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>
54 #include "openbsd-compat/openssl-compat.h"
83 #if defined(HAVE_SYS_PRCTL_H)
84 #include <sys/prctl.h> /* For prctl() and PR_SET_DUMPABLE */
101 u_int sockets_alloc = 0;
102 SocketEntry *sockets = NULL;
104 typedef struct identity {
105 TAILQ_ENTRY(identity) next;
114 TAILQ_HEAD(idqueue, identity) idlist;
117 /* private key table, one per protocol version */
122 /* pid of shell == parent of agent */
123 pid_t parent_pid = -1;
124 u_int parent_alive_interval = 0;
126 /* pathname and directory for AUTH_SOCKET */
127 char socket_name[MAXPATHLEN];
128 char socket_dir[MAXPATHLEN];
132 char *lock_passwd = NULL;
134 extern char *__progname;
136 /* Default lifetime (0 == forever) */
137 static int lifetime = 0;
140 close_socket(SocketEntry *e)
144 e->type = AUTH_UNUSED;
145 buffer_free(&e->input);
146 buffer_free(&e->output);
147 buffer_free(&e->request);
155 for (i = 0; i <=2; i++) {
156 TAILQ_INIT(&idtable[i].idlist);
157 idtable[i].nentries = 0;
161 /* return private key table for requested protocol version */
163 idtab_lookup(int version)
165 if (version < 1 || version > 2)
166 fatal("internal error, bad protocol version %d", version);
167 return &idtable[version];
171 free_identity(Identity *id)
178 /* return matching private key for given public key */
180 lookup_identity(Key *key, int version)
184 Idtab *tab = idtab_lookup(version);
185 TAILQ_FOREACH(id, &tab->idlist, next) {
186 if (key_equal(key, id->key))
192 /* Check confirmation of keysign request */
194 confirm_key(Identity *id)
199 p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX);
200 if (ask_permission("Allow use of key %s?\nKey fingerprint %s.",
208 /* send list of supported public keys to 'client' */
210 process_request_identities(SocketEntry *e, int version)
212 Idtab *tab = idtab_lookup(version);
217 buffer_put_char(&msg, (version == 1) ?
218 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
219 buffer_put_int(&msg, tab->nentries);
220 TAILQ_FOREACH(id, &tab->idlist, next) {
221 if (id->key->type == KEY_RSA1) {
222 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n));
223 buffer_put_bignum(&msg, id->key->rsa->e);
224 buffer_put_bignum(&msg, id->key->rsa->n);
228 key_to_blob(id->key, &blob, &blen);
229 buffer_put_string(&msg, blob, blen);
232 buffer_put_cstring(&msg, id->comment);
234 buffer_put_int(&e->output, buffer_len(&msg));
235 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
241 process_authentication_challenge1(SocketEntry *e)
243 u_char buf[32], mdbuf[16], session_id[16];
253 key = key_new(KEY_RSA1);
254 if ((challenge = BN_new()) == NULL)
255 fatal("process_authentication_challenge1: BN_new failed");
257 (void) buffer_get_int(&e->request); /* ignored */
258 buffer_get_bignum(&e->request, key->rsa->e);
259 buffer_get_bignum(&e->request, key->rsa->n);
260 buffer_get_bignum(&e->request, challenge);
262 /* Only protocol 1.1 is supported */
263 if (buffer_len(&e->request) == 0)
265 buffer_get(&e->request, session_id, 16);
266 response_type = buffer_get_int(&e->request);
267 if (response_type != 1)
270 id = lookup_identity(key, 1);
271 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) {
272 Key *private = id->key;
273 /* Decrypt the challenge using the private key. */
274 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0)
277 /* The response is MD5 of decrypted challenge plus session id. */
278 len = BN_num_bytes(challenge);
279 if (len <= 0 || len > 32) {
280 logit("process_authentication_challenge: bad challenge length %d", len);
284 BN_bn2bin(challenge, buf + 32 - len);
286 MD5_Update(&md, buf, 32);
287 MD5_Update(&md, session_id, 16);
288 MD5_Final(mdbuf, &md);
290 /* Send the response. */
291 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE);
292 for (i = 0; i < 16; i++)
293 buffer_put_char(&msg, mdbuf[i]);
298 /* Unknown identity or protocol error. Send failure. */
299 buffer_put_char(&msg, SSH_AGENT_FAILURE);
301 buffer_put_int(&e->output, buffer_len(&msg));
302 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
304 BN_clear_free(challenge);
310 process_sign_request2(SocketEntry *e)
312 u_char *blob, *data, *signature = NULL;
313 u_int blen, dlen, slen = 0;
314 extern int datafellows;
321 blob = buffer_get_string(&e->request, &blen);
322 data = buffer_get_string(&e->request, &dlen);
324 flags = buffer_get_int(&e->request);
325 if (flags & SSH_AGENT_OLD_SIGNATURE)
326 datafellows = SSH_BUG_SIGBLOB;
328 key = key_from_blob(blob, blen);
330 Identity *id = lookup_identity(key, 2);
331 if (id != NULL && (!id->confirm || confirm_key(id) == 0))
332 ok = key_sign(id->key, &signature, &slen, data, dlen);
337 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE);
338 buffer_put_string(&msg, signature, slen);
340 buffer_put_char(&msg, SSH_AGENT_FAILURE);
342 buffer_put_int(&e->output, buffer_len(&msg));
343 buffer_append(&e->output, buffer_ptr(&msg),
348 if (signature != NULL)
354 process_remove_identity(SocketEntry *e, int version)
363 key = key_new(KEY_RSA1);
364 bits = buffer_get_int(&e->request);
365 buffer_get_bignum(&e->request, key->rsa->e);
366 buffer_get_bignum(&e->request, key->rsa->n);
368 if (bits != key_size(key))
369 logit("Warning: identity keysize mismatch: actual %u, announced %u",
370 key_size(key), bits);
373 blob = buffer_get_string(&e->request, &blen);
374 key = key_from_blob(blob, blen);
379 Identity *id = lookup_identity(key, version);
382 * We have this key. Free the old key. Since we
383 * don't want to leave empty slots in the middle of
384 * the array, we actually free the key there and move
385 * all the entries between the empty slot and the end
388 Idtab *tab = idtab_lookup(version);
389 if (tab->nentries < 1)
390 fatal("process_remove_identity: "
391 "internal error: tab->nentries %d",
393 TAILQ_REMOVE(&tab->idlist, id, next);
400 buffer_put_int(&e->output, 1);
401 buffer_put_char(&e->output,
402 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
406 process_remove_all_identities(SocketEntry *e, int version)
408 Idtab *tab = idtab_lookup(version);
411 /* Loop over all identities and clear the keys. */
412 for (id = TAILQ_FIRST(&tab->idlist); id;
413 id = TAILQ_FIRST(&tab->idlist)) {
414 TAILQ_REMOVE(&tab->idlist, id, next);
418 /* Mark that there are no identities. */
422 buffer_put_int(&e->output, 1);
423 buffer_put_char(&e->output, SSH_AGENT_SUCCESS);
426 /* removes expired keys and returns number of seconds until the next expiry */
430 u_int deadline = 0, now = time(NULL);
435 for (version = 1; version < 3; version++) {
436 tab = idtab_lookup(version);
437 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) {
438 nxt = TAILQ_NEXT(id, next);
441 if (now >= id->death) {
442 debug("expiring key '%s'", id->comment);
443 TAILQ_REMOVE(&tab->idlist, id, next);
447 deadline = (deadline == 0) ? id->death :
448 MIN(deadline, id->death);
451 if (deadline == 0 || deadline <= now)
454 return (deadline - now);
458 process_add_identity(SocketEntry *e, int version)
460 Idtab *tab = idtab_lookup(version);
462 int type, success = 0, death = 0, confirm = 0;
463 char *type_name, *comment;
468 k = key_new_private(KEY_RSA1);
469 (void) buffer_get_int(&e->request); /* ignored */
470 buffer_get_bignum(&e->request, k->rsa->n);
471 buffer_get_bignum(&e->request, k->rsa->e);
472 buffer_get_bignum(&e->request, k->rsa->d);
473 buffer_get_bignum(&e->request, k->rsa->iqmp);
475 /* SSH and SSL have p and q swapped */
476 buffer_get_bignum(&e->request, k->rsa->q); /* p */
477 buffer_get_bignum(&e->request, k->rsa->p); /* q */
479 /* Generate additional parameters */
480 rsa_generate_additional_parameters(k->rsa);
483 type_name = buffer_get_string(&e->request, NULL);
484 type = key_type_from_name(type_name);
488 k = key_new_private(type);
489 buffer_get_bignum2(&e->request, k->dsa->p);
490 buffer_get_bignum2(&e->request, k->dsa->q);
491 buffer_get_bignum2(&e->request, k->dsa->g);
492 buffer_get_bignum2(&e->request, k->dsa->pub_key);
493 buffer_get_bignum2(&e->request, k->dsa->priv_key);
496 k = key_new_private(type);
497 buffer_get_bignum2(&e->request, k->rsa->n);
498 buffer_get_bignum2(&e->request, k->rsa->e);
499 buffer_get_bignum2(&e->request, k->rsa->d);
500 buffer_get_bignum2(&e->request, k->rsa->iqmp);
501 buffer_get_bignum2(&e->request, k->rsa->p);
502 buffer_get_bignum2(&e->request, k->rsa->q);
504 /* Generate additional parameters */
505 rsa_generate_additional_parameters(k->rsa);
508 buffer_clear(&e->request);
513 /* enable blinding */
517 if (RSA_blinding_on(k->rsa, NULL) != 1) {
518 error("process_add_identity: RSA_blinding_on failed");
524 comment = buffer_get_string(&e->request, NULL);
529 while (buffer_len(&e->request)) {
530 switch ((type = buffer_get_char(&e->request))) {
531 case SSH_AGENT_CONSTRAIN_LIFETIME:
532 death = time(NULL) + buffer_get_int(&e->request);
534 case SSH_AGENT_CONSTRAIN_CONFIRM:
538 error("process_add_identity: "
539 "Unknown constraint type %d", type);
546 if (lifetime && !death)
547 death = time(NULL) + lifetime;
548 if ((id = lookup_identity(k, version)) == NULL) {
549 id = xmalloc(sizeof(Identity));
551 TAILQ_INSERT_TAIL(&tab->idlist, id, next);
552 /* Increment the number of identities. */
558 id->comment = comment;
560 id->confirm = confirm;
562 buffer_put_int(&e->output, 1);
563 buffer_put_char(&e->output,
564 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
567 /* XXX todo: encrypt sensitive data with passphrase */
569 process_lock_agent(SocketEntry *e, int lock)
574 passwd = buffer_get_string(&e->request, NULL);
575 if (locked && !lock && strcmp(passwd, lock_passwd) == 0) {
577 memset(lock_passwd, 0, strlen(lock_passwd));
581 } else if (!locked && lock) {
583 lock_passwd = xstrdup(passwd);
586 memset(passwd, 0, strlen(passwd));
589 buffer_put_int(&e->output, 1);
590 buffer_put_char(&e->output,
591 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
595 no_identities(SocketEntry *e, u_int type)
600 buffer_put_char(&msg,
601 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ?
602 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
603 buffer_put_int(&msg, 0);
604 buffer_put_int(&e->output, buffer_len(&msg));
605 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
611 process_add_smartcard_key(SocketEntry *e)
613 char *sc_reader_id = NULL, *pin;
614 int i, type, version, success = 0, death = 0, confirm = 0;
619 sc_reader_id = buffer_get_string(&e->request, NULL);
620 pin = buffer_get_string(&e->request, NULL);
622 while (buffer_len(&e->request)) {
623 switch ((type = buffer_get_char(&e->request))) {
624 case SSH_AGENT_CONSTRAIN_LIFETIME:
625 death = time(NULL) + buffer_get_int(&e->request);
627 case SSH_AGENT_CONSTRAIN_CONFIRM:
631 error("process_add_smartcard_key: "
632 "Unknown constraint type %d", type);
638 if (lifetime && !death)
639 death = time(NULL) + lifetime;
641 keys = sc_get_keys(sc_reader_id, pin);
645 if (keys == NULL || keys[0] == NULL) {
646 error("sc_get_keys failed");
649 for (i = 0; keys[i] != NULL; i++) {
651 version = k->type == KEY_RSA1 ? 1 : 2;
652 tab = idtab_lookup(version);
653 if (lookup_identity(k, version) == NULL) {
654 id = xmalloc(sizeof(Identity));
656 id->comment = sc_get_key_label(k);
658 id->confirm = confirm;
659 TAILQ_INSERT_TAIL(&tab->idlist, id, next);
669 buffer_put_int(&e->output, 1);
670 buffer_put_char(&e->output,
671 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
675 process_remove_smartcard_key(SocketEntry *e)
677 char *sc_reader_id = NULL, *pin;
678 int i, version, success = 0;
679 Key **keys, *k = NULL;
683 sc_reader_id = buffer_get_string(&e->request, NULL);
684 pin = buffer_get_string(&e->request, NULL);
685 keys = sc_get_keys(sc_reader_id, pin);
689 if (keys == NULL || keys[0] == NULL) {
690 error("sc_get_keys failed");
693 for (i = 0; keys[i] != NULL; i++) {
695 version = k->type == KEY_RSA1 ? 1 : 2;
696 if ((id = lookup_identity(k, version)) != NULL) {
697 tab = idtab_lookup(version);
698 TAILQ_REMOVE(&tab->idlist, id, next);
708 buffer_put_int(&e->output, 1);
709 buffer_put_char(&e->output,
710 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
712 #endif /* SMARTCARD */
714 /* dispatch incoming messages */
717 process_message(SocketEntry *e)
722 if (buffer_len(&e->input) < 5)
723 return; /* Incomplete message. */
724 cp = buffer_ptr(&e->input);
725 msg_len = get_u32(cp);
726 if (msg_len > 256 * 1024) {
730 if (buffer_len(&e->input) < msg_len + 4)
733 /* move the current input to e->request */
734 buffer_consume(&e->input, 4);
735 buffer_clear(&e->request);
736 buffer_append(&e->request, buffer_ptr(&e->input), msg_len);
737 buffer_consume(&e->input, msg_len);
738 type = buffer_get_char(&e->request);
740 /* check wheter agent is locked */
741 if (locked && type != SSH_AGENTC_UNLOCK) {
742 buffer_clear(&e->request);
744 case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
745 case SSH2_AGENTC_REQUEST_IDENTITIES:
746 /* send empty lists */
747 no_identities(e, type);
750 /* send a fail message for all other request types */
751 buffer_put_int(&e->output, 1);
752 buffer_put_char(&e->output, SSH_AGENT_FAILURE);
757 debug("type %d", type);
759 case SSH_AGENTC_LOCK:
760 case SSH_AGENTC_UNLOCK:
761 process_lock_agent(e, type == SSH_AGENTC_LOCK);
764 case SSH_AGENTC_RSA_CHALLENGE:
765 process_authentication_challenge1(e);
767 case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
768 process_request_identities(e, 1);
770 case SSH_AGENTC_ADD_RSA_IDENTITY:
771 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED:
772 process_add_identity(e, 1);
774 case SSH_AGENTC_REMOVE_RSA_IDENTITY:
775 process_remove_identity(e, 1);
777 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
778 process_remove_all_identities(e, 1);
781 case SSH2_AGENTC_SIGN_REQUEST:
782 process_sign_request2(e);
784 case SSH2_AGENTC_REQUEST_IDENTITIES:
785 process_request_identities(e, 2);
787 case SSH2_AGENTC_ADD_IDENTITY:
788 case SSH2_AGENTC_ADD_ID_CONSTRAINED:
789 process_add_identity(e, 2);
791 case SSH2_AGENTC_REMOVE_IDENTITY:
792 process_remove_identity(e, 2);
794 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
795 process_remove_all_identities(e, 2);
798 case SSH_AGENTC_ADD_SMARTCARD_KEY:
799 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED:
800 process_add_smartcard_key(e);
802 case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
803 process_remove_smartcard_key(e);
805 #endif /* SMARTCARD */
807 /* Unknown message. Respond with failure. */
808 error("Unknown message %d", type);
809 buffer_clear(&e->request);
810 buffer_put_int(&e->output, 1);
811 buffer_put_char(&e->output, SSH_AGENT_FAILURE);
817 new_socket(sock_type type, int fd)
819 u_int i, old_alloc, new_alloc;
826 for (i = 0; i < sockets_alloc; i++)
827 if (sockets[i].type == AUTH_UNUSED) {
829 buffer_init(&sockets[i].input);
830 buffer_init(&sockets[i].output);
831 buffer_init(&sockets[i].request);
832 sockets[i].type = type;
835 old_alloc = sockets_alloc;
836 new_alloc = sockets_alloc + 10;
837 sockets = xrealloc(sockets, new_alloc, sizeof(sockets[0]));
838 for (i = old_alloc; i < new_alloc; i++)
839 sockets[i].type = AUTH_UNUSED;
840 sockets_alloc = new_alloc;
841 sockets[old_alloc].fd = fd;
842 buffer_init(&sockets[old_alloc].input);
843 buffer_init(&sockets[old_alloc].output);
844 buffer_init(&sockets[old_alloc].request);
845 sockets[old_alloc].type = type;
849 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp,
850 struct timeval **tvpp)
852 u_int i, sz, deadline;
854 static struct timeval tv;
856 for (i = 0; i < sockets_alloc; i++) {
857 switch (sockets[i].type) {
859 case AUTH_CONNECTION:
860 n = MAX(n, sockets[i].fd);
865 fatal("Unknown socket type %d", sockets[i].type);
870 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
871 if (*fdrp == NULL || sz > *nallocp) {
881 debug("XXX shrink: %d < %d", n, *fdl);
883 memset(*fdrp, 0, sz);
884 memset(*fdwp, 0, sz);
886 for (i = 0; i < sockets_alloc; i++) {
887 switch (sockets[i].type) {
889 case AUTH_CONNECTION:
890 FD_SET(sockets[i].fd, *fdrp);
891 if (buffer_len(&sockets[i].output) > 0)
892 FD_SET(sockets[i].fd, *fdwp);
899 if (parent_alive_interval != 0)
900 deadline = (deadline == 0) ? parent_alive_interval :
901 MIN(deadline, parent_alive_interval);
905 tv.tv_sec = deadline;
913 after_select(fd_set *readset, fd_set *writeset)
915 struct sockaddr_un sunaddr;
923 for (i = 0; i < sockets_alloc; i++)
924 switch (sockets[i].type) {
928 if (FD_ISSET(sockets[i].fd, readset)) {
929 slen = sizeof(sunaddr);
930 sock = accept(sockets[i].fd,
931 (struct sockaddr *)&sunaddr, &slen);
933 error("accept from AUTH_SOCKET: %s",
937 if (getpeereid(sock, &euid, &egid) < 0) {
938 error("getpeereid %d failed: %s",
939 sock, strerror(errno));
943 if ((euid != 0) && (getuid() != euid)) {
944 error("uid mismatch: "
945 "peer euid %u != uid %u",
946 (u_int) euid, (u_int) getuid());
950 new_socket(AUTH_CONNECTION, sock);
953 case AUTH_CONNECTION:
954 if (buffer_len(&sockets[i].output) > 0 &&
955 FD_ISSET(sockets[i].fd, writeset)) {
957 len = write(sockets[i].fd,
958 buffer_ptr(&sockets[i].output),
959 buffer_len(&sockets[i].output));
960 if (len == -1 && (errno == EAGAIN ||
966 close_socket(&sockets[i]);
969 buffer_consume(&sockets[i].output, len);
971 if (FD_ISSET(sockets[i].fd, readset)) {
973 len = read(sockets[i].fd, buf, sizeof(buf));
974 if (len == -1 && (errno == EAGAIN ||
980 close_socket(&sockets[i]);
983 buffer_append(&sockets[i].input, buf, len);
984 process_message(&sockets[i]);
988 fatal("Unknown type %d", sockets[i].type);
1010 cleanup_handler(int sig)
1017 check_parent_exists(void)
1019 if (parent_pid != -1 && kill(parent_pid, 0) < 0) {
1020 /* printf("Parent has died - Authentication agent exiting.\n"); */
1029 fprintf(stderr, "usage: %s [options] [command [arg ...]]\n",
1031 fprintf(stderr, "Options:\n");
1032 fprintf(stderr, " -c Generate C-shell commands on stdout.\n");
1033 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n");
1034 fprintf(stderr, " -k Kill the current agent.\n");
1035 fprintf(stderr, " -d Debug mode.\n");
1036 fprintf(stderr, " -a socket Bind agent socket to given name.\n");
1037 fprintf(stderr, " -t life Default identity lifetime (seconds).\n");
1042 main(int ac, char **av)
1044 int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0;
1045 int sock, fd, ch, result, saved_errno;
1047 char *shell, *format, *pidstr, *agentsocket = NULL;
1048 fd_set *readsetp = NULL, *writesetp = NULL;
1049 struct sockaddr_un sunaddr;
1050 #ifdef HAVE_SETRLIMIT
1055 extern char *optarg;
1057 char pidstrbuf[1 + 3 * sizeof pid];
1058 struct timeval *tvp = NULL;
1060 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1067 #if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE)
1068 /* Disable ptrace on Linux without sgid bit */
1069 prctl(PR_SET_DUMPABLE, 0);
1072 SSLeay_add_all_algorithms();
1074 __progname = ssh_get_progname(av[0]);
1078 while ((ch = getopt(ac, av, "cdksa:t:")) != -1) {
1099 agentsocket = optarg;
1102 if ((lifetime = convtime(optarg)) == -1) {
1103 fprintf(stderr, "Invalid lifetime\n");
1114 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag))
1117 if (ac == 0 && !c_flag && !s_flag) {
1118 shell = getenv("SHELL");
1119 if (shell != NULL &&
1120 strncmp(shell + strlen(shell) - 3, "csh", 3) == 0)
1124 const char *errstr = NULL;
1126 pidstr = getenv(SSH_AGENTPID_ENV_NAME);
1127 if (pidstr == NULL) {
1128 fprintf(stderr, "%s not set, cannot kill agent\n",
1129 SSH_AGENTPID_ENV_NAME);
1132 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr);
1135 "%s=\"%s\", which is not a good PID: %s\n",
1136 SSH_AGENTPID_ENV_NAME, pidstr, errstr);
1139 if (kill(pid, SIGTERM) == -1) {
1143 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
1144 printf(format, SSH_AUTHSOCKET_ENV_NAME);
1145 printf(format, SSH_AGENTPID_ENV_NAME);
1146 printf("echo Agent pid %ld killed;\n", (long)pid);
1149 parent_pid = getpid();
1151 if (agentsocket == NULL) {
1152 /* Create private directory for agent socket */
1153 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXXXX", sizeof socket_dir);
1154 if (mkdtemp(socket_dir) == NULL) {
1155 perror("mkdtemp: private socket dir");
1158 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir,
1161 /* Try to use specified agent socket */
1162 socket_dir[0] = '\0';
1163 strlcpy(socket_name, agentsocket, sizeof socket_name);
1167 * Create socket early so it will exist before command gets run from
1170 sock = socket(AF_UNIX, SOCK_STREAM, 0);
1173 *socket_name = '\0'; /* Don't unlink any existing file */
1176 memset(&sunaddr, 0, sizeof(sunaddr));
1177 sunaddr.sun_family = AF_UNIX;
1178 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path));
1179 prev_mask = umask(0177);
1180 if (bind(sock, (struct sockaddr *) &sunaddr, sizeof(sunaddr)) < 0) {
1182 *socket_name = '\0'; /* Don't unlink any existing file */
1187 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
1193 * Fork, and have the parent execute the command, if any, or present
1194 * the socket data. The child continues as the authentication agent.
1197 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1);
1198 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1199 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1200 SSH_AUTHSOCKET_ENV_NAME);
1201 printf("echo Agent pid %ld;\n", (long)parent_pid);
1209 if (pid != 0) { /* Parent - execute the given command. */
1211 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid);
1213 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1214 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1215 SSH_AUTHSOCKET_ENV_NAME);
1216 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
1217 SSH_AGENTPID_ENV_NAME);
1218 printf("echo Agent pid %ld;\n", (long)pid);
1221 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 ||
1222 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) {
1231 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0);
1233 if (setsid() == -1) {
1234 error("setsid: %s", strerror(errno));
1239 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1240 /* XXX might close listen socket */
1241 (void)dup2(fd, STDIN_FILENO);
1242 (void)dup2(fd, STDOUT_FILENO);
1243 (void)dup2(fd, STDERR_FILENO);
1248 #ifdef HAVE_SETRLIMIT
1249 /* deny core dumps, since memory contains unencrypted private keys */
1250 rlim.rlim_cur = rlim.rlim_max = 0;
1251 if (setrlimit(RLIMIT_CORE, &rlim) < 0) {
1252 error("setrlimit RLIMIT_CORE: %s", strerror(errno));
1258 new_socket(AUTH_SOCKET, sock);
1260 parent_alive_interval = 10;
1263 signal(SIGINT, SIG_IGN);
1264 signal(SIGPIPE, SIG_IGN);
1265 signal(SIGHUP, cleanup_handler);
1266 signal(SIGTERM, cleanup_handler);
1270 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp);
1271 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp);
1272 saved_errno = errno;
1273 if (parent_alive_interval != 0)
1274 check_parent_exists();
1275 (void) reaper(); /* remove expired keys */
1277 if (saved_errno == EINTR)
1279 fatal("select: %s", strerror(saved_errno));
1280 } else if (result > 0)
1281 after_select(readsetp, writesetp);