1 /* $OpenBSD: ssh-agent.c,v 1.153 2006/10/06 02:29:19 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.
40 #include <sys/types.h>
41 #include <sys/param.h>
42 #include <sys/resource.h>
44 #include <sys/socket.h>
45 #ifdef HAVE_SYS_TIME_H
46 # include <sys/time.h>
51 #include "openbsd-compat/sys-queue.h"
53 #include <openssl/evp.h>
54 #include <openssl/md5.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;
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);
428 u_int now = time(NULL);
433 for (version = 1; version < 3; version++) {
434 tab = idtab_lookup(version);
435 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) {
436 nxt = TAILQ_NEXT(id, next);
437 if (id->death != 0 && now >= id->death) {
438 TAILQ_REMOVE(&tab->idlist, id, next);
447 process_add_identity(SocketEntry *e, int version)
449 Idtab *tab = idtab_lookup(version);
450 int type, success = 0, death = 0, confirm = 0;
451 char *type_name, *comment;
456 k = key_new_private(KEY_RSA1);
457 (void) buffer_get_int(&e->request); /* ignored */
458 buffer_get_bignum(&e->request, k->rsa->n);
459 buffer_get_bignum(&e->request, k->rsa->e);
460 buffer_get_bignum(&e->request, k->rsa->d);
461 buffer_get_bignum(&e->request, k->rsa->iqmp);
463 /* SSH and SSL have p and q swapped */
464 buffer_get_bignum(&e->request, k->rsa->q); /* p */
465 buffer_get_bignum(&e->request, k->rsa->p); /* q */
467 /* Generate additional parameters */
468 rsa_generate_additional_parameters(k->rsa);
471 type_name = buffer_get_string(&e->request, NULL);
472 type = key_type_from_name(type_name);
476 k = key_new_private(type);
477 buffer_get_bignum2(&e->request, k->dsa->p);
478 buffer_get_bignum2(&e->request, k->dsa->q);
479 buffer_get_bignum2(&e->request, k->dsa->g);
480 buffer_get_bignum2(&e->request, k->dsa->pub_key);
481 buffer_get_bignum2(&e->request, k->dsa->priv_key);
484 k = key_new_private(type);
485 buffer_get_bignum2(&e->request, k->rsa->n);
486 buffer_get_bignum2(&e->request, k->rsa->e);
487 buffer_get_bignum2(&e->request, k->rsa->d);
488 buffer_get_bignum2(&e->request, k->rsa->iqmp);
489 buffer_get_bignum2(&e->request, k->rsa->p);
490 buffer_get_bignum2(&e->request, k->rsa->q);
492 /* Generate additional parameters */
493 rsa_generate_additional_parameters(k->rsa);
496 buffer_clear(&e->request);
501 /* enable blinding */
505 if (RSA_blinding_on(k->rsa, NULL) != 1) {
506 error("process_add_identity: RSA_blinding_on failed");
512 comment = buffer_get_string(&e->request, NULL);
518 while (buffer_len(&e->request)) {
519 switch (buffer_get_char(&e->request)) {
520 case SSH_AGENT_CONSTRAIN_LIFETIME:
521 death = time(NULL) + buffer_get_int(&e->request);
523 case SSH_AGENT_CONSTRAIN_CONFIRM:
530 if (lifetime && !death)
531 death = time(NULL) + lifetime;
532 if (lookup_identity(k, version) == NULL) {
533 Identity *id = xmalloc(sizeof(Identity));
535 id->comment = comment;
537 id->confirm = confirm;
538 TAILQ_INSERT_TAIL(&tab->idlist, id, next);
539 /* Increment the number of identities. */
546 buffer_put_int(&e->output, 1);
547 buffer_put_char(&e->output,
548 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
551 /* XXX todo: encrypt sensitive data with passphrase */
553 process_lock_agent(SocketEntry *e, int lock)
558 passwd = buffer_get_string(&e->request, NULL);
559 if (locked && !lock && strcmp(passwd, lock_passwd) == 0) {
561 memset(lock_passwd, 0, strlen(lock_passwd));
565 } else if (!locked && lock) {
567 lock_passwd = xstrdup(passwd);
570 memset(passwd, 0, strlen(passwd));
573 buffer_put_int(&e->output, 1);
574 buffer_put_char(&e->output,
575 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
579 no_identities(SocketEntry *e, u_int type)
584 buffer_put_char(&msg,
585 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ?
586 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
587 buffer_put_int(&msg, 0);
588 buffer_put_int(&e->output, buffer_len(&msg));
589 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
595 process_add_smartcard_key (SocketEntry *e)
597 char *sc_reader_id = NULL, *pin;
598 int i, version, success = 0, death = 0, confirm = 0;
603 sc_reader_id = buffer_get_string(&e->request, NULL);
604 pin = buffer_get_string(&e->request, NULL);
606 while (buffer_len(&e->request)) {
607 switch (buffer_get_char(&e->request)) {
608 case SSH_AGENT_CONSTRAIN_LIFETIME:
609 death = time(NULL) + buffer_get_int(&e->request);
611 case SSH_AGENT_CONSTRAIN_CONFIRM:
618 if (lifetime && !death)
619 death = time(NULL) + lifetime;
621 keys = sc_get_keys(sc_reader_id, pin);
625 if (keys == NULL || keys[0] == NULL) {
626 error("sc_get_keys failed");
629 for (i = 0; keys[i] != NULL; i++) {
631 version = k->type == KEY_RSA1 ? 1 : 2;
632 tab = idtab_lookup(version);
633 if (lookup_identity(k, version) == NULL) {
634 id = xmalloc(sizeof(Identity));
636 id->comment = sc_get_key_label(k);
638 id->confirm = confirm;
639 TAILQ_INSERT_TAIL(&tab->idlist, id, next);
649 buffer_put_int(&e->output, 1);
650 buffer_put_char(&e->output,
651 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
655 process_remove_smartcard_key(SocketEntry *e)
657 char *sc_reader_id = NULL, *pin;
658 int i, version, success = 0;
659 Key **keys, *k = NULL;
663 sc_reader_id = buffer_get_string(&e->request, NULL);
664 pin = buffer_get_string(&e->request, NULL);
665 keys = sc_get_keys(sc_reader_id, pin);
669 if (keys == NULL || keys[0] == NULL) {
670 error("sc_get_keys failed");
673 for (i = 0; keys[i] != NULL; i++) {
675 version = k->type == KEY_RSA1 ? 1 : 2;
676 if ((id = lookup_identity(k, version)) != NULL) {
677 tab = idtab_lookup(version);
678 TAILQ_REMOVE(&tab->idlist, id, next);
688 buffer_put_int(&e->output, 1);
689 buffer_put_char(&e->output,
690 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
692 #endif /* SMARTCARD */
694 /* dispatch incoming messages */
697 process_message(SocketEntry *e)
705 if (buffer_len(&e->input) < 5)
706 return; /* Incomplete message. */
707 cp = buffer_ptr(&e->input);
708 msg_len = get_u32(cp);
709 if (msg_len > 256 * 1024) {
713 if (buffer_len(&e->input) < msg_len + 4)
716 /* move the current input to e->request */
717 buffer_consume(&e->input, 4);
718 buffer_clear(&e->request);
719 buffer_append(&e->request, buffer_ptr(&e->input), msg_len);
720 buffer_consume(&e->input, msg_len);
721 type = buffer_get_char(&e->request);
723 /* check wheter agent is locked */
724 if (locked && type != SSH_AGENTC_UNLOCK) {
725 buffer_clear(&e->request);
727 case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
728 case SSH2_AGENTC_REQUEST_IDENTITIES:
729 /* send empty lists */
730 no_identities(e, type);
733 /* send a fail message for all other request types */
734 buffer_put_int(&e->output, 1);
735 buffer_put_char(&e->output, SSH_AGENT_FAILURE);
740 debug("type %d", type);
742 case SSH_AGENTC_LOCK:
743 case SSH_AGENTC_UNLOCK:
744 process_lock_agent(e, type == SSH_AGENTC_LOCK);
747 case SSH_AGENTC_RSA_CHALLENGE:
748 process_authentication_challenge1(e);
750 case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
751 process_request_identities(e, 1);
753 case SSH_AGENTC_ADD_RSA_IDENTITY:
754 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED:
755 process_add_identity(e, 1);
757 case SSH_AGENTC_REMOVE_RSA_IDENTITY:
758 process_remove_identity(e, 1);
760 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
761 process_remove_all_identities(e, 1);
764 case SSH2_AGENTC_SIGN_REQUEST:
765 process_sign_request2(e);
767 case SSH2_AGENTC_REQUEST_IDENTITIES:
768 process_request_identities(e, 2);
770 case SSH2_AGENTC_ADD_IDENTITY:
771 case SSH2_AGENTC_ADD_ID_CONSTRAINED:
772 process_add_identity(e, 2);
774 case SSH2_AGENTC_REMOVE_IDENTITY:
775 process_remove_identity(e, 2);
777 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
778 process_remove_all_identities(e, 2);
781 case SSH_AGENTC_ADD_SMARTCARD_KEY:
782 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED:
783 process_add_smartcard_key(e);
785 case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
786 process_remove_smartcard_key(e);
788 #endif /* SMARTCARD */
790 /* Unknown message. Respond with failure. */
791 error("Unknown message %d", type);
792 buffer_clear(&e->request);
793 buffer_put_int(&e->output, 1);
794 buffer_put_char(&e->output, SSH_AGENT_FAILURE);
800 new_socket(sock_type type, int fd)
802 u_int i, old_alloc, new_alloc;
809 for (i = 0; i < sockets_alloc; i++)
810 if (sockets[i].type == AUTH_UNUSED) {
812 buffer_init(&sockets[i].input);
813 buffer_init(&sockets[i].output);
814 buffer_init(&sockets[i].request);
815 sockets[i].type = type;
818 old_alloc = sockets_alloc;
819 new_alloc = sockets_alloc + 10;
820 sockets = xrealloc(sockets, new_alloc, sizeof(sockets[0]));
821 for (i = old_alloc; i < new_alloc; i++)
822 sockets[i].type = AUTH_UNUSED;
823 sockets_alloc = new_alloc;
824 sockets[old_alloc].fd = fd;
825 buffer_init(&sockets[old_alloc].input);
826 buffer_init(&sockets[old_alloc].output);
827 buffer_init(&sockets[old_alloc].request);
828 sockets[old_alloc].type = type;
832 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp)
837 for (i = 0; i < sockets_alloc; i++) {
838 switch (sockets[i].type) {
840 case AUTH_CONNECTION:
841 n = MAX(n, sockets[i].fd);
846 fatal("Unknown socket type %d", sockets[i].type);
851 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
852 if (*fdrp == NULL || sz > *nallocp) {
862 debug("XXX shrink: %d < %d", n, *fdl);
864 memset(*fdrp, 0, sz);
865 memset(*fdwp, 0, sz);
867 for (i = 0; i < sockets_alloc; i++) {
868 switch (sockets[i].type) {
870 case AUTH_CONNECTION:
871 FD_SET(sockets[i].fd, *fdrp);
872 if (buffer_len(&sockets[i].output) > 0)
873 FD_SET(sockets[i].fd, *fdwp);
883 after_select(fd_set *readset, fd_set *writeset)
885 struct sockaddr_un sunaddr;
893 for (i = 0; i < sockets_alloc; i++)
894 switch (sockets[i].type) {
898 if (FD_ISSET(sockets[i].fd, readset)) {
899 slen = sizeof(sunaddr);
900 sock = accept(sockets[i].fd,
901 (struct sockaddr *)&sunaddr, &slen);
903 error("accept from AUTH_SOCKET: %s",
907 if (getpeereid(sock, &euid, &egid) < 0) {
908 error("getpeereid %d failed: %s",
909 sock, strerror(errno));
913 if ((euid != 0) && (getuid() != euid)) {
914 error("uid mismatch: "
915 "peer euid %u != uid %u",
916 (u_int) euid, (u_int) getuid());
920 new_socket(AUTH_CONNECTION, sock);
923 case AUTH_CONNECTION:
924 if (buffer_len(&sockets[i].output) > 0 &&
925 FD_ISSET(sockets[i].fd, writeset)) {
927 len = write(sockets[i].fd,
928 buffer_ptr(&sockets[i].output),
929 buffer_len(&sockets[i].output));
930 if (len == -1 && (errno == EAGAIN ||
936 close_socket(&sockets[i]);
939 buffer_consume(&sockets[i].output, len);
941 if (FD_ISSET(sockets[i].fd, readset)) {
943 len = read(sockets[i].fd, buf, sizeof(buf));
944 if (len == -1 && (errno == EAGAIN ||
950 close_socket(&sockets[i]);
953 buffer_append(&sockets[i].input, buf, len);
954 process_message(&sockets[i]);
958 fatal("Unknown type %d", sockets[i].type);
980 cleanup_handler(int sig)
988 check_parent_exists(int sig)
990 int save_errno = errno;
992 if (parent_pid != -1 && kill(parent_pid, 0) < 0) {
993 /* printf("Parent has died - Authentication agent exiting.\n"); */
994 cleanup_handler(sig); /* safe */
996 mysignal(SIGALRM, check_parent_exists);
1004 fprintf(stderr, "Usage: %s [options] [command [args ...]]\n",
1006 fprintf(stderr, "Options:\n");
1007 fprintf(stderr, " -c Generate C-shell commands on stdout.\n");
1008 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n");
1009 fprintf(stderr, " -k Kill the current agent.\n");
1010 fprintf(stderr, " -d Debug mode.\n");
1011 fprintf(stderr, " -a socket Bind agent socket to given name.\n");
1012 fprintf(stderr, " -t life Default identity lifetime (seconds).\n");
1017 main(int ac, char **av)
1019 int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0;
1022 char *shell, *format, *pidstr, *agentsocket = NULL;
1023 fd_set *readsetp = NULL, *writesetp = NULL;
1024 struct sockaddr_un sunaddr;
1025 #ifdef HAVE_SETRLIMIT
1030 extern char *optarg;
1032 char pidstrbuf[1 + 3 * sizeof pid];
1034 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1042 #if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE)
1043 /* Disable ptrace on Linux without sgid bit */
1044 prctl(PR_SET_DUMPABLE, 0);
1047 SSLeay_add_all_algorithms();
1049 __progname = ssh_get_progname(av[0]);
1053 while ((ch = getopt(ac, av, "cdksa:t:")) != -1) {
1074 agentsocket = optarg;
1077 if ((lifetime = convtime(optarg)) == -1) {
1078 fprintf(stderr, "Invalid lifetime\n");
1089 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag))
1092 if (ac == 0 && !c_flag && !s_flag) {
1093 shell = getenv("SHELL");
1094 if (shell != NULL &&
1095 strncmp(shell + strlen(shell) - 3, "csh", 3) == 0)
1099 const char *errstr = NULL;
1101 pidstr = getenv(SSH_AGENTPID_ENV_NAME);
1102 if (pidstr == NULL) {
1103 fprintf(stderr, "%s not set, cannot kill agent\n",
1104 SSH_AGENTPID_ENV_NAME);
1107 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr);
1110 "%s=\"%s\", which is not a good PID: %s\n",
1111 SSH_AGENTPID_ENV_NAME, pidstr, errstr);
1114 if (kill(pid, SIGTERM) == -1) {
1118 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
1119 printf(format, SSH_AUTHSOCKET_ENV_NAME);
1120 printf(format, SSH_AGENTPID_ENV_NAME);
1121 printf("echo Agent pid %ld killed;\n", (long)pid);
1124 parent_pid = getpid();
1126 if (agentsocket == NULL) {
1127 /* Create private directory for agent socket */
1128 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXXXX", sizeof socket_dir);
1129 if (mkdtemp(socket_dir) == NULL) {
1130 perror("mkdtemp: private socket dir");
1133 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir,
1136 /* Try to use specified agent socket */
1137 socket_dir[0] = '\0';
1138 strlcpy(socket_name, agentsocket, sizeof socket_name);
1142 * Create socket early so it will exist before command gets run from
1145 sock = socket(AF_UNIX, SOCK_STREAM, 0);
1148 *socket_name = '\0'; /* Don't unlink any existing file */
1151 memset(&sunaddr, 0, sizeof(sunaddr));
1152 sunaddr.sun_family = AF_UNIX;
1153 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path));
1154 prev_mask = umask(0177);
1155 if (bind(sock, (struct sockaddr *) &sunaddr, sizeof(sunaddr)) < 0) {
1157 *socket_name = '\0'; /* Don't unlink any existing file */
1162 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
1168 * Fork, and have the parent execute the command, if any, or present
1169 * the socket data. The child continues as the authentication agent.
1172 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1);
1173 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1174 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1175 SSH_AUTHSOCKET_ENV_NAME);
1176 printf("echo Agent pid %ld;\n", (long)parent_pid);
1184 if (pid != 0) { /* Parent - execute the given command. */
1186 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid);
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(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
1192 SSH_AGENTPID_ENV_NAME);
1193 printf("echo Agent pid %ld;\n", (long)pid);
1196 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 ||
1197 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) {
1206 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0);
1208 if (setsid() == -1) {
1209 error("setsid: %s", strerror(errno));
1214 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1215 /* XXX might close listen socket */
1216 (void)dup2(fd, STDIN_FILENO);
1217 (void)dup2(fd, STDOUT_FILENO);
1218 (void)dup2(fd, STDERR_FILENO);
1223 #ifdef HAVE_SETRLIMIT
1224 /* deny core dumps, since memory contains unencrypted private keys */
1225 rlim.rlim_cur = rlim.rlim_max = 0;
1226 if (setrlimit(RLIMIT_CORE, &rlim) < 0) {
1227 error("setrlimit RLIMIT_CORE: %s", strerror(errno));
1233 new_socket(AUTH_SOCKET, sock);
1235 mysignal(SIGALRM, check_parent_exists);
1240 signal(SIGINT, SIG_IGN);
1241 signal(SIGPIPE, SIG_IGN);
1242 signal(SIGHUP, cleanup_handler);
1243 signal(SIGTERM, cleanup_handler);
1247 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc);
1248 if (select(max_fd + 1, readsetp, writesetp, NULL, NULL) < 0) {
1251 fatal("select: %s", strerror(errno));
1253 after_select(readsetp, writesetp);