1 /* $OpenBSD: ssh-agent.c,v 1.147 2006/07/25 02:59:21 stevesk 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>
41 #include <sys/socket.h>
42 #ifdef HAVE_SYS_TIME_H
43 # include <sys/time.h>
48 #include "openbsd-compat/sys-queue.h"
49 #include <sys/resource.h>
51 #include <openssl/evp.h>
52 #include <openssl/md5.h>
79 #if defined(HAVE_SYS_PRCTL_H)
80 #include <sys/prctl.h> /* For prctl() and PR_SET_DUMPABLE */
97 u_int sockets_alloc = 0;
98 SocketEntry *sockets = NULL;
100 typedef struct identity {
101 TAILQ_ENTRY(identity) next;
110 TAILQ_HEAD(idqueue, identity) idlist;
113 /* private key table, one per protocol version */
118 /* pid of shell == parent of agent */
119 pid_t parent_pid = -1;
121 /* pathname and directory for AUTH_SOCKET */
122 char socket_name[MAXPATHLEN];
123 char socket_dir[MAXPATHLEN];
127 char *lock_passwd = NULL;
129 extern char *__progname;
131 /* Default lifetime (0 == forever) */
132 static int lifetime = 0;
135 close_socket(SocketEntry *e)
139 e->type = AUTH_UNUSED;
140 buffer_free(&e->input);
141 buffer_free(&e->output);
142 buffer_free(&e->request);
150 for (i = 0; i <=2; i++) {
151 TAILQ_INIT(&idtable[i].idlist);
152 idtable[i].nentries = 0;
156 /* return private key table for requested protocol version */
158 idtab_lookup(int version)
160 if (version < 1 || version > 2)
161 fatal("internal error, bad protocol version %d", version);
162 return &idtable[version];
166 free_identity(Identity *id)
173 /* return matching private key for given public key */
175 lookup_identity(Key *key, int version)
179 Idtab *tab = idtab_lookup(version);
180 TAILQ_FOREACH(id, &tab->idlist, next) {
181 if (key_equal(key, id->key))
187 /* Check confirmation of keysign request */
189 confirm_key(Identity *id)
194 p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX);
195 if (ask_permission("Allow use of key %s?\nKey fingerprint %s.",
203 /* send list of supported public keys to 'client' */
205 process_request_identities(SocketEntry *e, int version)
207 Idtab *tab = idtab_lookup(version);
212 buffer_put_char(&msg, (version == 1) ?
213 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
214 buffer_put_int(&msg, tab->nentries);
215 TAILQ_FOREACH(id, &tab->idlist, next) {
216 if (id->key->type == KEY_RSA1) {
217 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n));
218 buffer_put_bignum(&msg, id->key->rsa->e);
219 buffer_put_bignum(&msg, id->key->rsa->n);
223 key_to_blob(id->key, &blob, &blen);
224 buffer_put_string(&msg, blob, blen);
227 buffer_put_cstring(&msg, id->comment);
229 buffer_put_int(&e->output, buffer_len(&msg));
230 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
236 process_authentication_challenge1(SocketEntry *e)
238 u_char buf[32], mdbuf[16], session_id[16];
248 key = key_new(KEY_RSA1);
249 if ((challenge = BN_new()) == NULL)
250 fatal("process_authentication_challenge1: BN_new failed");
252 (void) buffer_get_int(&e->request); /* ignored */
253 buffer_get_bignum(&e->request, key->rsa->e);
254 buffer_get_bignum(&e->request, key->rsa->n);
255 buffer_get_bignum(&e->request, challenge);
257 /* Only protocol 1.1 is supported */
258 if (buffer_len(&e->request) == 0)
260 buffer_get(&e->request, session_id, 16);
261 response_type = buffer_get_int(&e->request);
262 if (response_type != 1)
265 id = lookup_identity(key, 1);
266 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) {
267 Key *private = id->key;
268 /* Decrypt the challenge using the private key. */
269 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0)
272 /* The response is MD5 of decrypted challenge plus session id. */
273 len = BN_num_bytes(challenge);
274 if (len <= 0 || len > 32) {
275 logit("process_authentication_challenge: bad challenge length %d", len);
279 BN_bn2bin(challenge, buf + 32 - len);
281 MD5_Update(&md, buf, 32);
282 MD5_Update(&md, session_id, 16);
283 MD5_Final(mdbuf, &md);
285 /* Send the response. */
286 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE);
287 for (i = 0; i < 16; i++)
288 buffer_put_char(&msg, mdbuf[i]);
293 /* Unknown identity or protocol error. Send failure. */
294 buffer_put_char(&msg, SSH_AGENT_FAILURE);
296 buffer_put_int(&e->output, buffer_len(&msg));
297 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
299 BN_clear_free(challenge);
305 process_sign_request2(SocketEntry *e)
307 u_char *blob, *data, *signature = NULL;
308 u_int blen, dlen, slen = 0;
309 extern int datafellows;
316 blob = buffer_get_string(&e->request, &blen);
317 data = buffer_get_string(&e->request, &dlen);
319 flags = buffer_get_int(&e->request);
320 if (flags & SSH_AGENT_OLD_SIGNATURE)
321 datafellows = SSH_BUG_SIGBLOB;
323 key = key_from_blob(blob, blen);
325 Identity *id = lookup_identity(key, 2);
326 if (id != NULL && (!id->confirm || confirm_key(id) == 0))
327 ok = key_sign(id->key, &signature, &slen, data, dlen);
332 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE);
333 buffer_put_string(&msg, signature, slen);
335 buffer_put_char(&msg, SSH_AGENT_FAILURE);
337 buffer_put_int(&e->output, buffer_len(&msg));
338 buffer_append(&e->output, buffer_ptr(&msg),
343 if (signature != NULL)
349 process_remove_identity(SocketEntry *e, int version)
358 key = key_new(KEY_RSA1);
359 bits = buffer_get_int(&e->request);
360 buffer_get_bignum(&e->request, key->rsa->e);
361 buffer_get_bignum(&e->request, key->rsa->n);
363 if (bits != key_size(key))
364 logit("Warning: identity keysize mismatch: actual %u, announced %u",
365 key_size(key), bits);
368 blob = buffer_get_string(&e->request, &blen);
369 key = key_from_blob(blob, blen);
374 Identity *id = lookup_identity(key, version);
377 * We have this key. Free the old key. Since we
378 * don't want to leave empty slots in the middle of
379 * the array, we actually free the key there and move
380 * all the entries between the empty slot and the end
383 Idtab *tab = idtab_lookup(version);
384 if (tab->nentries < 1)
385 fatal("process_remove_identity: "
386 "internal error: tab->nentries %d",
388 TAILQ_REMOVE(&tab->idlist, id, next);
395 buffer_put_int(&e->output, 1);
396 buffer_put_char(&e->output,
397 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
401 process_remove_all_identities(SocketEntry *e, int version)
403 Idtab *tab = idtab_lookup(version);
406 /* Loop over all identities and clear the keys. */
407 for (id = TAILQ_FIRST(&tab->idlist); id;
408 id = TAILQ_FIRST(&tab->idlist)) {
409 TAILQ_REMOVE(&tab->idlist, id, next);
413 /* Mark that there are no identities. */
417 buffer_put_int(&e->output, 1);
418 buffer_put_char(&e->output, SSH_AGENT_SUCCESS);
424 u_int now = time(NULL);
429 for (version = 1; version < 3; version++) {
430 tab = idtab_lookup(version);
431 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) {
432 nxt = TAILQ_NEXT(id, next);
433 if (id->death != 0 && now >= id->death) {
434 TAILQ_REMOVE(&tab->idlist, id, next);
443 process_add_identity(SocketEntry *e, int version)
445 Idtab *tab = idtab_lookup(version);
446 int type, success = 0, death = 0, confirm = 0;
447 char *type_name, *comment;
452 k = key_new_private(KEY_RSA1);
453 (void) buffer_get_int(&e->request); /* ignored */
454 buffer_get_bignum(&e->request, k->rsa->n);
455 buffer_get_bignum(&e->request, k->rsa->e);
456 buffer_get_bignum(&e->request, k->rsa->d);
457 buffer_get_bignum(&e->request, k->rsa->iqmp);
459 /* SSH and SSL have p and q swapped */
460 buffer_get_bignum(&e->request, k->rsa->q); /* p */
461 buffer_get_bignum(&e->request, k->rsa->p); /* q */
463 /* Generate additional parameters */
464 rsa_generate_additional_parameters(k->rsa);
467 type_name = buffer_get_string(&e->request, NULL);
468 type = key_type_from_name(type_name);
472 k = key_new_private(type);
473 buffer_get_bignum2(&e->request, k->dsa->p);
474 buffer_get_bignum2(&e->request, k->dsa->q);
475 buffer_get_bignum2(&e->request, k->dsa->g);
476 buffer_get_bignum2(&e->request, k->dsa->pub_key);
477 buffer_get_bignum2(&e->request, k->dsa->priv_key);
480 k = key_new_private(type);
481 buffer_get_bignum2(&e->request, k->rsa->n);
482 buffer_get_bignum2(&e->request, k->rsa->e);
483 buffer_get_bignum2(&e->request, k->rsa->d);
484 buffer_get_bignum2(&e->request, k->rsa->iqmp);
485 buffer_get_bignum2(&e->request, k->rsa->p);
486 buffer_get_bignum2(&e->request, k->rsa->q);
488 /* Generate additional parameters */
489 rsa_generate_additional_parameters(k->rsa);
492 buffer_clear(&e->request);
497 /* enable blinding */
501 if (RSA_blinding_on(k->rsa, NULL) != 1) {
502 error("process_add_identity: RSA_blinding_on failed");
508 comment = buffer_get_string(&e->request, NULL);
514 while (buffer_len(&e->request)) {
515 switch (buffer_get_char(&e->request)) {
516 case SSH_AGENT_CONSTRAIN_LIFETIME:
517 death = time(NULL) + buffer_get_int(&e->request);
519 case SSH_AGENT_CONSTRAIN_CONFIRM:
526 if (lifetime && !death)
527 death = time(NULL) + lifetime;
528 if (lookup_identity(k, version) == NULL) {
529 Identity *id = xmalloc(sizeof(Identity));
531 id->comment = comment;
533 id->confirm = confirm;
534 TAILQ_INSERT_TAIL(&tab->idlist, id, next);
535 /* Increment the number of identities. */
542 buffer_put_int(&e->output, 1);
543 buffer_put_char(&e->output,
544 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
547 /* XXX todo: encrypt sensitive data with passphrase */
549 process_lock_agent(SocketEntry *e, int lock)
554 passwd = buffer_get_string(&e->request, NULL);
555 if (locked && !lock && strcmp(passwd, lock_passwd) == 0) {
557 memset(lock_passwd, 0, strlen(lock_passwd));
561 } else if (!locked && lock) {
563 lock_passwd = xstrdup(passwd);
566 memset(passwd, 0, strlen(passwd));
569 buffer_put_int(&e->output, 1);
570 buffer_put_char(&e->output,
571 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
575 no_identities(SocketEntry *e, u_int type)
580 buffer_put_char(&msg,
581 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ?
582 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
583 buffer_put_int(&msg, 0);
584 buffer_put_int(&e->output, buffer_len(&msg));
585 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
591 process_add_smartcard_key (SocketEntry *e)
593 char *sc_reader_id = NULL, *pin;
594 int i, version, success = 0, death = 0, confirm = 0;
599 sc_reader_id = buffer_get_string(&e->request, NULL);
600 pin = buffer_get_string(&e->request, NULL);
602 while (buffer_len(&e->request)) {
603 switch (buffer_get_char(&e->request)) {
604 case SSH_AGENT_CONSTRAIN_LIFETIME:
605 death = time(NULL) + buffer_get_int(&e->request);
607 case SSH_AGENT_CONSTRAIN_CONFIRM:
614 if (lifetime && !death)
615 death = time(NULL) + lifetime;
617 keys = sc_get_keys(sc_reader_id, pin);
621 if (keys == NULL || keys[0] == NULL) {
622 error("sc_get_keys failed");
625 for (i = 0; keys[i] != NULL; i++) {
627 version = k->type == KEY_RSA1 ? 1 : 2;
628 tab = idtab_lookup(version);
629 if (lookup_identity(k, version) == NULL) {
630 id = xmalloc(sizeof(Identity));
632 id->comment = sc_get_key_label(k);
634 id->confirm = confirm;
635 TAILQ_INSERT_TAIL(&tab->idlist, id, next);
645 buffer_put_int(&e->output, 1);
646 buffer_put_char(&e->output,
647 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
651 process_remove_smartcard_key(SocketEntry *e)
653 char *sc_reader_id = NULL, *pin;
654 int i, version, success = 0;
655 Key **keys, *k = NULL;
659 sc_reader_id = buffer_get_string(&e->request, NULL);
660 pin = buffer_get_string(&e->request, NULL);
661 keys = sc_get_keys(sc_reader_id, pin);
665 if (keys == NULL || keys[0] == NULL) {
666 error("sc_get_keys failed");
669 for (i = 0; keys[i] != NULL; i++) {
671 version = k->type == KEY_RSA1 ? 1 : 2;
672 if ((id = lookup_identity(k, version)) != NULL) {
673 tab = idtab_lookup(version);
674 TAILQ_REMOVE(&tab->idlist, id, next);
684 buffer_put_int(&e->output, 1);
685 buffer_put_char(&e->output,
686 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
688 #endif /* SMARTCARD */
690 /* dispatch incoming messages */
693 process_message(SocketEntry *e)
701 if (buffer_len(&e->input) < 5)
702 return; /* Incomplete message. */
703 cp = buffer_ptr(&e->input);
704 msg_len = get_u32(cp);
705 if (msg_len > 256 * 1024) {
709 if (buffer_len(&e->input) < msg_len + 4)
712 /* move the current input to e->request */
713 buffer_consume(&e->input, 4);
714 buffer_clear(&e->request);
715 buffer_append(&e->request, buffer_ptr(&e->input), msg_len);
716 buffer_consume(&e->input, msg_len);
717 type = buffer_get_char(&e->request);
719 /* check wheter agent is locked */
720 if (locked && type != SSH_AGENTC_UNLOCK) {
721 buffer_clear(&e->request);
723 case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
724 case SSH2_AGENTC_REQUEST_IDENTITIES:
725 /* send empty lists */
726 no_identities(e, type);
729 /* send a fail message for all other request types */
730 buffer_put_int(&e->output, 1);
731 buffer_put_char(&e->output, SSH_AGENT_FAILURE);
736 debug("type %d", type);
738 case SSH_AGENTC_LOCK:
739 case SSH_AGENTC_UNLOCK:
740 process_lock_agent(e, type == SSH_AGENTC_LOCK);
743 case SSH_AGENTC_RSA_CHALLENGE:
744 process_authentication_challenge1(e);
746 case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
747 process_request_identities(e, 1);
749 case SSH_AGENTC_ADD_RSA_IDENTITY:
750 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED:
751 process_add_identity(e, 1);
753 case SSH_AGENTC_REMOVE_RSA_IDENTITY:
754 process_remove_identity(e, 1);
756 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
757 process_remove_all_identities(e, 1);
760 case SSH2_AGENTC_SIGN_REQUEST:
761 process_sign_request2(e);
763 case SSH2_AGENTC_REQUEST_IDENTITIES:
764 process_request_identities(e, 2);
766 case SSH2_AGENTC_ADD_IDENTITY:
767 case SSH2_AGENTC_ADD_ID_CONSTRAINED:
768 process_add_identity(e, 2);
770 case SSH2_AGENTC_REMOVE_IDENTITY:
771 process_remove_identity(e, 2);
773 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
774 process_remove_all_identities(e, 2);
777 case SSH_AGENTC_ADD_SMARTCARD_KEY:
778 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED:
779 process_add_smartcard_key(e);
781 case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
782 process_remove_smartcard_key(e);
784 #endif /* SMARTCARD */
786 /* Unknown message. Respond with failure. */
787 error("Unknown message %d", type);
788 buffer_clear(&e->request);
789 buffer_put_int(&e->output, 1);
790 buffer_put_char(&e->output, SSH_AGENT_FAILURE);
796 new_socket(sock_type type, int fd)
798 u_int i, old_alloc, new_alloc;
805 for (i = 0; i < sockets_alloc; i++)
806 if (sockets[i].type == AUTH_UNUSED) {
808 buffer_init(&sockets[i].input);
809 buffer_init(&sockets[i].output);
810 buffer_init(&sockets[i].request);
811 sockets[i].type = type;
814 old_alloc = sockets_alloc;
815 new_alloc = sockets_alloc + 10;
816 sockets = xrealloc(sockets, new_alloc, sizeof(sockets[0]));
817 for (i = old_alloc; i < new_alloc; i++)
818 sockets[i].type = AUTH_UNUSED;
819 sockets_alloc = new_alloc;
820 sockets[old_alloc].fd = fd;
821 buffer_init(&sockets[old_alloc].input);
822 buffer_init(&sockets[old_alloc].output);
823 buffer_init(&sockets[old_alloc].request);
824 sockets[old_alloc].type = type;
828 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp)
833 for (i = 0; i < sockets_alloc; i++) {
834 switch (sockets[i].type) {
836 case AUTH_CONNECTION:
837 n = MAX(n, sockets[i].fd);
842 fatal("Unknown socket type %d", sockets[i].type);
847 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
848 if (*fdrp == NULL || sz > *nallocp) {
858 debug("XXX shrink: %d < %d", n, *fdl);
860 memset(*fdrp, 0, sz);
861 memset(*fdwp, 0, sz);
863 for (i = 0; i < sockets_alloc; i++) {
864 switch (sockets[i].type) {
866 case AUTH_CONNECTION:
867 FD_SET(sockets[i].fd, *fdrp);
868 if (buffer_len(&sockets[i].output) > 0)
869 FD_SET(sockets[i].fd, *fdwp);
879 after_select(fd_set *readset, fd_set *writeset)
881 struct sockaddr_un sunaddr;
889 for (i = 0; i < sockets_alloc; i++)
890 switch (sockets[i].type) {
894 if (FD_ISSET(sockets[i].fd, readset)) {
895 slen = sizeof(sunaddr);
896 sock = accept(sockets[i].fd,
897 (struct sockaddr *)&sunaddr, &slen);
899 error("accept from AUTH_SOCKET: %s",
903 if (getpeereid(sock, &euid, &egid) < 0) {
904 error("getpeereid %d failed: %s",
905 sock, strerror(errno));
909 if ((euid != 0) && (getuid() != euid)) {
910 error("uid mismatch: "
911 "peer euid %u != uid %u",
912 (u_int) euid, (u_int) getuid());
916 new_socket(AUTH_CONNECTION, sock);
919 case AUTH_CONNECTION:
920 if (buffer_len(&sockets[i].output) > 0 &&
921 FD_ISSET(sockets[i].fd, writeset)) {
923 len = write(sockets[i].fd,
924 buffer_ptr(&sockets[i].output),
925 buffer_len(&sockets[i].output));
926 if (len == -1 && (errno == EAGAIN ||
932 close_socket(&sockets[i]);
935 buffer_consume(&sockets[i].output, len);
937 if (FD_ISSET(sockets[i].fd, readset)) {
939 len = read(sockets[i].fd, buf, sizeof(buf));
940 if (len == -1 && (errno == EAGAIN ||
946 close_socket(&sockets[i]);
949 buffer_append(&sockets[i].input, buf, len);
950 process_message(&sockets[i]);
954 fatal("Unknown type %d", sockets[i].type);
976 cleanup_handler(int sig)
984 check_parent_exists(int sig)
986 int save_errno = errno;
988 if (parent_pid != -1 && kill(parent_pid, 0) < 0) {
989 /* printf("Parent has died - Authentication agent exiting.\n"); */
990 cleanup_handler(sig); /* safe */
992 mysignal(SIGALRM, check_parent_exists);
1000 fprintf(stderr, "Usage: %s [options] [command [args ...]]\n",
1002 fprintf(stderr, "Options:\n");
1003 fprintf(stderr, " -c Generate C-shell commands on stdout.\n");
1004 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n");
1005 fprintf(stderr, " -k Kill the current agent.\n");
1006 fprintf(stderr, " -d Debug mode.\n");
1007 fprintf(stderr, " -a socket Bind agent socket to given name.\n");
1008 fprintf(stderr, " -t life Default identity lifetime (seconds).\n");
1013 main(int ac, char **av)
1015 int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0;
1018 char *shell, *format, *pidstr, *agentsocket = NULL;
1019 fd_set *readsetp = NULL, *writesetp = NULL;
1020 struct sockaddr_un sunaddr;
1021 #ifdef HAVE_SETRLIMIT
1026 extern char *optarg;
1028 char pidstrbuf[1 + 3 * sizeof pid];
1030 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1037 #if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE)
1038 /* Disable ptrace on Linux without sgid bit */
1039 prctl(PR_SET_DUMPABLE, 0);
1042 SSLeay_add_all_algorithms();
1044 __progname = ssh_get_progname(av[0]);
1048 while ((ch = getopt(ac, av, "cdksa:t:")) != -1) {
1069 agentsocket = optarg;
1072 if ((lifetime = convtime(optarg)) == -1) {
1073 fprintf(stderr, "Invalid lifetime\n");
1084 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag))
1087 if (ac == 0 && !c_flag && !s_flag) {
1088 shell = getenv("SHELL");
1089 if (shell != NULL &&
1090 strncmp(shell + strlen(shell) - 3, "csh", 3) == 0)
1094 const char *errstr = NULL;
1096 pidstr = getenv(SSH_AGENTPID_ENV_NAME);
1097 if (pidstr == NULL) {
1098 fprintf(stderr, "%s not set, cannot kill agent\n",
1099 SSH_AGENTPID_ENV_NAME);
1102 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr);
1105 "%s=\"%s\", which is not a good PID: %s\n",
1106 SSH_AGENTPID_ENV_NAME, pidstr, errstr);
1109 if (kill(pid, SIGTERM) == -1) {
1113 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
1114 printf(format, SSH_AUTHSOCKET_ENV_NAME);
1115 printf(format, SSH_AGENTPID_ENV_NAME);
1116 printf("echo Agent pid %ld killed;\n", (long)pid);
1119 parent_pid = getpid();
1121 if (agentsocket == NULL) {
1122 /* Create private directory for agent socket */
1123 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXXXX", sizeof socket_dir);
1124 if (mkdtemp(socket_dir) == NULL) {
1125 perror("mkdtemp: private socket dir");
1128 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir,
1131 /* Try to use specified agent socket */
1132 socket_dir[0] = '\0';
1133 strlcpy(socket_name, agentsocket, sizeof socket_name);
1137 * Create socket early so it will exist before command gets run from
1140 sock = socket(AF_UNIX, SOCK_STREAM, 0);
1143 *socket_name = '\0'; /* Don't unlink any existing file */
1146 memset(&sunaddr, 0, sizeof(sunaddr));
1147 sunaddr.sun_family = AF_UNIX;
1148 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path));
1149 prev_mask = umask(0177);
1150 if (bind(sock, (struct sockaddr *) &sunaddr, sizeof(sunaddr)) < 0) {
1152 *socket_name = '\0'; /* Don't unlink any existing file */
1157 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
1163 * Fork, and have the parent execute the command, if any, or present
1164 * the socket data. The child continues as the authentication agent.
1167 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1);
1168 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1169 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1170 SSH_AUTHSOCKET_ENV_NAME);
1171 printf("echo Agent pid %ld;\n", (long)parent_pid);
1179 if (pid != 0) { /* Parent - execute the given command. */
1181 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid);
1183 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1184 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1185 SSH_AUTHSOCKET_ENV_NAME);
1186 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
1187 SSH_AGENTPID_ENV_NAME);
1188 printf("echo Agent pid %ld;\n", (long)pid);
1191 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 ||
1192 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) {
1201 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0);
1203 if (setsid() == -1) {
1204 error("setsid: %s", strerror(errno));
1209 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1210 /* XXX might close listen socket */
1211 (void)dup2(fd, STDIN_FILENO);
1212 (void)dup2(fd, STDOUT_FILENO);
1213 (void)dup2(fd, STDERR_FILENO);
1218 #ifdef HAVE_SETRLIMIT
1219 /* deny core dumps, since memory contains unencrypted private keys */
1220 rlim.rlim_cur = rlim.rlim_max = 0;
1221 if (setrlimit(RLIMIT_CORE, &rlim) < 0) {
1222 error("setrlimit RLIMIT_CORE: %s", strerror(errno));
1228 new_socket(AUTH_SOCKET, sock);
1230 mysignal(SIGALRM, check_parent_exists);
1235 signal(SIGINT, SIG_IGN);
1236 signal(SIGPIPE, SIG_IGN);
1237 signal(SIGHUP, cleanup_handler);
1238 signal(SIGTERM, cleanup_handler);
1242 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc);
1243 if (select(max_fd + 1, readsetp, writesetp, NULL, NULL) < 0) {
1246 fatal("select: %s", strerror(errno));
1248 after_select(readsetp, writesetp);