1 /* $OpenBSD: ssh-agent.c,v 1.37 2000/09/21 11:07:51 markus Exp $ */ 2 3 /* 4 * Author: Tatu Ylonen <ylo@cs.hut.fi> 5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 6 * All rights reserved 7 * The authentication agent program. 8 * 9 * As far as I am concerned, the code I have written for this software 10 * can be used freely for any purpose. Any derived versions of this 11 * software must be clearly marked as such, and if the derived work is 12 * incompatible with the protocol description in the RFC file, it must be 13 * called by a name other than "ssh" or "Secure Shell". 14 * 15 * SSH2 implementation, 16 * Copyright (c) 2000 Markus Friedl. All rights reserved. 17 * 18 * Redistribution and use in source and binary forms, with or without 19 * modification, are permitted provided that the following conditions 20 * are met: 21 * 1. Redistributions of source code must retain the above copyright 22 * notice, this list of conditions and the following disclaimer. 23 * 2. Redistributions in binary form must reproduce the above copyright 24 * notice, this list of conditions and the following disclaimer in the 25 * documentation and/or other materials provided with the distribution. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 28 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 29 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 30 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 31 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 32 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 33 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 34 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 35 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 36 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 #include "includes.h" 40 RCSID("$OpenBSD: ssh-agent.c,v 1.37 2000/09/21 11:07:51 markus Exp $"); 41 RCSID("$FreeBSD$"); 42 43 #include "ssh.h" 44 #include "rsa.h" 45 #include "buffer.h" 46 #include "bufaux.h" 47 #include "xmalloc.h" 48 #include "packet.h" 49 #include "getput.h" 50 #include "mpaux.h" 51 52 #include <openssl/evp.h> 53 #include <openssl/md5.h> 54 #include <openssl/dsa.h> 55 #include <openssl/rsa.h> 56 #include "key.h" 57 #include "authfd.h" 58 #include "dsa.h" 59 #include "kex.h" 60 #include "compat.h" 61 62 typedef struct { 63 int fd; 64 enum { 65 AUTH_UNUSED, AUTH_SOCKET, AUTH_CONNECTION 66 } type; 67 Buffer input; 68 Buffer output; 69 } SocketEntry; 70 71 unsigned int sockets_alloc = 0; 72 SocketEntry *sockets = NULL; 73 74 typedef struct { 75 Key *key; 76 char *comment; 77 } Identity; 78 79 typedef struct { 80 int nentries; 81 Identity *identities; 82 } Idtab; 83 84 /* private key table, one per protocol version */ 85 Idtab idtable[3]; 86 87 int max_fd = 0; 88 89 /* pid of shell == parent of agent */ 90 pid_t parent_pid = -1; 91 92 /* pathname and directory for AUTH_SOCKET */ 93 char socket_name[1024]; 94 char socket_dir[1024]; 95 96 extern char *__progname; 97 98 void 99 idtab_init(void) 100 { 101 int i; 102 for (i = 0; i <=2; i++){ 103 idtable[i].identities = NULL; 104 idtable[i].nentries = 0; 105 } 106 } 107 108 /* return private key table for requested protocol version */ 109 Idtab * 110 idtab_lookup(int version) 111 { 112 if (version < 1 || version > 2) 113 fatal("internal error, bad protocol version %d", version); 114 return &idtable[version]; 115 } 116 117 /* return matching private key for given public key */ 118 Key * 119 lookup_private_key(Key *key, int *idx, int version) 120 { 121 int i; 122 Idtab *tab = idtab_lookup(version); 123 for (i = 0; i < tab->nentries; i++) { 124 if (key_equal(key, tab->identities[i].key)) { 125 if (idx != NULL) 126 *idx = i; 127 return tab->identities[i].key; 128 } 129 } 130 return NULL; 131 } 132 133 /* send list of supported public keys to 'client' */ 134 void 135 process_request_identities(SocketEntry *e, int version) 136 { 137 Idtab *tab = idtab_lookup(version); 138 Buffer msg; 139 int i; 140 141 buffer_init(&msg); 142 buffer_put_char(&msg, (version == 1) ? 143 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 144 buffer_put_int(&msg, tab->nentries); 145 for (i = 0; i < tab->nentries; i++) { 146 Identity *id = &tab->identities[i]; 147 if (id->key->type == KEY_RSA) { 148 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n)); 149 buffer_put_bignum(&msg, id->key->rsa->e); 150 buffer_put_bignum(&msg, id->key->rsa->n); 151 } else { 152 unsigned char *blob; 153 unsigned int blen; 154 dsa_make_key_blob(id->key, &blob, &blen); 155 buffer_put_string(&msg, blob, blen); 156 xfree(blob); 157 } 158 buffer_put_cstring(&msg, id->comment); 159 } 160 buffer_put_int(&e->output, buffer_len(&msg)); 161 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 162 buffer_free(&msg); 163 } 164 165 /* ssh1 only */ 166 void 167 process_authentication_challenge1(SocketEntry *e) 168 { 169 Key *key, *private; 170 BIGNUM *challenge; 171 int i, len; 172 Buffer msg; 173 MD5_CTX md; 174 unsigned char buf[32], mdbuf[16], session_id[16]; 175 unsigned int response_type; 176 177 buffer_init(&msg); 178 key = key_new(KEY_RSA); 179 challenge = BN_new(); 180 181 buffer_get_int(&e->input); /* ignored */ 182 buffer_get_bignum(&e->input, key->rsa->e); 183 buffer_get_bignum(&e->input, key->rsa->n); 184 buffer_get_bignum(&e->input, challenge); 185 186 /* Only protocol 1.1 is supported */ 187 if (buffer_len(&e->input) == 0) 188 goto failure; 189 buffer_get(&e->input, (char *) session_id, 16); 190 response_type = buffer_get_int(&e->input); 191 if (response_type != 1) 192 goto failure; 193 194 private = lookup_private_key(key, NULL, 1); 195 if (private != NULL) { 196 /* Decrypt the challenge using the private key. */ 197 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0) 198 goto failure; 199 200 /* The response is MD5 of decrypted challenge plus session id. */ 201 len = BN_num_bytes(challenge); 202 if (len <= 0 || len > 32) { 203 log("process_authentication_challenge: bad challenge length %d", len); 204 goto failure; 205 } 206 memset(buf, 0, 32); 207 BN_bn2bin(challenge, buf + 32 - len); 208 MD5_Init(&md); 209 MD5_Update(&md, buf, 32); 210 MD5_Update(&md, session_id, 16); 211 MD5_Final(mdbuf, &md); 212 213 /* Send the response. */ 214 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE); 215 for (i = 0; i < 16; i++) 216 buffer_put_char(&msg, mdbuf[i]); 217 goto send; 218 } 219 220 failure: 221 /* Unknown identity or protocol error. Send failure. */ 222 buffer_put_char(&msg, SSH_AGENT_FAILURE); 223 send: 224 buffer_put_int(&e->output, buffer_len(&msg)); 225 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 226 key_free(key); 227 BN_clear_free(challenge); 228 buffer_free(&msg); 229 } 230 231 /* ssh2 only */ 232 void 233 process_sign_request2(SocketEntry *e) 234 { 235 extern int datafellows; 236 Key *key, *private; 237 unsigned char *blob, *data, *signature = NULL; 238 unsigned int blen, dlen, slen = 0; 239 int flags; 240 Buffer msg; 241 int ok = -1; 242 243 datafellows = 0; 244 245 blob = buffer_get_string(&e->input, &blen); 246 data = buffer_get_string(&e->input, &dlen); 247 248 flags = buffer_get_int(&e->input); 249 if (flags & SSH_AGENT_OLD_SIGNATURE) 250 datafellows = SSH_BUG_SIGBLOB; 251 252 key = dsa_key_from_blob(blob, blen); 253 if (key != NULL) { 254 private = lookup_private_key(key, NULL, 2); 255 if (private != NULL) 256 ok = dsa_sign(private, &signature, &slen, data, dlen); 257 } 258 key_free(key); 259 buffer_init(&msg); 260 if (ok == 0) { 261 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); 262 buffer_put_string(&msg, signature, slen); 263 } else { 264 buffer_put_char(&msg, SSH_AGENT_FAILURE); 265 } 266 buffer_put_int(&e->output, buffer_len(&msg)); 267 buffer_append(&e->output, buffer_ptr(&msg), 268 buffer_len(&msg)); 269 buffer_free(&msg); 270 xfree(data); 271 xfree(blob); 272 if (signature != NULL) 273 xfree(signature); 274 } 275 276 /* shared */ 277 void 278 process_remove_identity(SocketEntry *e, int version) 279 { 280 Key *key = NULL, *private; 281 unsigned char *blob; 282 unsigned int blen; 283 unsigned int bits; 284 int success = 0; 285 286 switch(version){ 287 case 1: 288 key = key_new(KEY_RSA); 289 bits = buffer_get_int(&e->input); 290 buffer_get_bignum(&e->input, key->rsa->e); 291 buffer_get_bignum(&e->input, key->rsa->n); 292 293 if (bits != key_size(key)) 294 log("Warning: identity keysize mismatch: actual %d, announced %d", 295 key_size(key), bits); 296 break; 297 case 2: 298 blob = buffer_get_string(&e->input, &blen); 299 key = dsa_key_from_blob(blob, blen); 300 xfree(blob); 301 break; 302 } 303 if (key != NULL) { 304 int idx; 305 private = lookup_private_key(key, &idx, version); 306 if (private != NULL) { 307 /* 308 * We have this key. Free the old key. Since we 309 * don\'t want to leave empty slots in the middle of 310 * the array, we actually free the key there and copy 311 * data from the last entry. 312 */ 313 Idtab *tab = idtab_lookup(version); 314 key_free(tab->identities[idx].key); 315 xfree(tab->identities[idx].comment); 316 if (idx != tab->nentries) 317 tab->identities[idx] = tab->identities[tab->nentries]; 318 tab->nentries--; 319 success = 1; 320 } 321 key_free(key); 322 } 323 buffer_put_int(&e->output, 1); 324 buffer_put_char(&e->output, 325 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 326 } 327 328 void 329 process_remove_all_identities(SocketEntry *e, int version) 330 { 331 unsigned int i; 332 Idtab *tab = idtab_lookup(version); 333 334 /* Loop over all identities and clear the keys. */ 335 for (i = 0; i < tab->nentries; i++) { 336 key_free(tab->identities[i].key); 337 xfree(tab->identities[i].comment); 338 } 339 340 /* Mark that there are no identities. */ 341 tab->nentries = 0; 342 343 /* Send success. */ 344 buffer_put_int(&e->output, 1); 345 buffer_put_char(&e->output, SSH_AGENT_SUCCESS); 346 return; 347 } 348 349 void 350 process_add_identity(SocketEntry *e, int version) 351 { 352 Key *k = NULL; 353 RSA *rsa; 354 BIGNUM *aux; 355 BN_CTX *ctx; 356 char *type; 357 char *comment; 358 int success = 0; 359 Idtab *tab = idtab_lookup(version); 360 361 switch (version) { 362 case 1: 363 k = key_new(KEY_RSA); 364 rsa = k->rsa; 365 366 /* allocate mem for private key */ 367 /* XXX rsa->n and rsa->e are already allocated */ 368 rsa->d = BN_new(); 369 rsa->iqmp = BN_new(); 370 rsa->q = BN_new(); 371 rsa->p = BN_new(); 372 rsa->dmq1 = BN_new(); 373 rsa->dmp1 = BN_new(); 374 375 buffer_get_int(&e->input); /* ignored */ 376 377 buffer_get_bignum(&e->input, rsa->n); 378 buffer_get_bignum(&e->input, rsa->e); 379 buffer_get_bignum(&e->input, rsa->d); 380 buffer_get_bignum(&e->input, rsa->iqmp); 381 382 /* SSH and SSL have p and q swapped */ 383 buffer_get_bignum(&e->input, rsa->q); /* p */ 384 buffer_get_bignum(&e->input, rsa->p); /* q */ 385 386 /* Generate additional parameters */ 387 aux = BN_new(); 388 ctx = BN_CTX_new(); 389 390 BN_sub(aux, rsa->q, BN_value_one()); 391 BN_mod(rsa->dmq1, rsa->d, aux, ctx); 392 393 BN_sub(aux, rsa->p, BN_value_one()); 394 BN_mod(rsa->dmp1, rsa->d, aux, ctx); 395 396 BN_clear_free(aux); 397 BN_CTX_free(ctx); 398 399 break; 400 case 2: 401 type = buffer_get_string(&e->input, NULL); 402 if (strcmp(type, KEX_DSS)) { 403 buffer_clear(&e->input); 404 xfree(type); 405 goto send; 406 } 407 xfree(type); 408 409 k = key_new(KEY_DSA); 410 411 /* allocate mem for private key */ 412 k->dsa->priv_key = BN_new(); 413 414 buffer_get_bignum2(&e->input, k->dsa->p); 415 buffer_get_bignum2(&e->input, k->dsa->q); 416 buffer_get_bignum2(&e->input, k->dsa->g); 417 buffer_get_bignum2(&e->input, k->dsa->pub_key); 418 buffer_get_bignum2(&e->input, k->dsa->priv_key); 419 420 break; 421 } 422 423 comment = buffer_get_string(&e->input, NULL); 424 if (k == NULL) { 425 xfree(comment); 426 goto send; 427 } 428 success = 1; 429 if (lookup_private_key(k, NULL, version) == NULL) { 430 if (tab->nentries == 0) 431 tab->identities = xmalloc(sizeof(Identity)); 432 else 433 tab->identities = xrealloc(tab->identities, 434 (tab->nentries + 1) * sizeof(Identity)); 435 tab->identities[tab->nentries].key = k; 436 tab->identities[tab->nentries].comment = comment; 437 /* Increment the number of identities. */ 438 tab->nentries++; 439 } else { 440 key_free(k); 441 xfree(comment); 442 } 443 send: 444 buffer_put_int(&e->output, 1); 445 buffer_put_char(&e->output, 446 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 447 } 448 449 /* dispatch incoming messages */ 450 451 void 452 process_message(SocketEntry *e) 453 { 454 unsigned int msg_len; 455 unsigned int type; 456 unsigned char *cp; 457 if (buffer_len(&e->input) < 5) 458 return; /* Incomplete message. */ 459 cp = (unsigned char *) buffer_ptr(&e->input); 460 msg_len = GET_32BIT(cp); 461 if (msg_len > 256 * 1024) { 462 shutdown(e->fd, SHUT_RDWR); 463 close(e->fd); 464 e->type = AUTH_UNUSED; 465 return; 466 } 467 if (buffer_len(&e->input) < msg_len + 4) 468 return; 469 buffer_consume(&e->input, 4); 470 type = buffer_get_char(&e->input); 471 472 switch (type) { 473 /* ssh1 */ 474 case SSH_AGENTC_RSA_CHALLENGE: 475 process_authentication_challenge1(e); 476 break; 477 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 478 process_request_identities(e, 1); 479 break; 480 case SSH_AGENTC_ADD_RSA_IDENTITY: 481 process_add_identity(e, 1); 482 break; 483 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 484 process_remove_identity(e, 1); 485 break; 486 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 487 process_remove_all_identities(e, 1); 488 break; 489 /* ssh2 */ 490 case SSH2_AGENTC_SIGN_REQUEST: 491 process_sign_request2(e); 492 break; 493 case SSH2_AGENTC_REQUEST_IDENTITIES: 494 process_request_identities(e, 2); 495 break; 496 case SSH2_AGENTC_ADD_IDENTITY: 497 process_add_identity(e, 2); 498 break; 499 case SSH2_AGENTC_REMOVE_IDENTITY: 500 process_remove_identity(e, 2); 501 break; 502 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 503 process_remove_all_identities(e, 2); 504 break; 505 default: 506 /* Unknown message. Respond with failure. */ 507 error("Unknown message %d", type); 508 buffer_clear(&e->input); 509 buffer_put_int(&e->output, 1); 510 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 511 break; 512 } 513 } 514 515 void 516 new_socket(int type, int fd) 517 { 518 unsigned int i, old_alloc; 519 if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) 520 error("fcntl O_NONBLOCK: %s", strerror(errno)); 521 522 if (fd > max_fd) 523 max_fd = fd; 524 525 for (i = 0; i < sockets_alloc; i++) 526 if (sockets[i].type == AUTH_UNUSED) { 527 sockets[i].fd = fd; 528 sockets[i].type = type; 529 buffer_init(&sockets[i].input); 530 buffer_init(&sockets[i].output); 531 return; 532 } 533 old_alloc = sockets_alloc; 534 sockets_alloc += 10; 535 if (sockets) 536 sockets = xrealloc(sockets, sockets_alloc * sizeof(sockets[0])); 537 else 538 sockets = xmalloc(sockets_alloc * sizeof(sockets[0])); 539 for (i = old_alloc; i < sockets_alloc; i++) 540 sockets[i].type = AUTH_UNUSED; 541 sockets[old_alloc].type = type; 542 sockets[old_alloc].fd = fd; 543 buffer_init(&sockets[old_alloc].input); 544 buffer_init(&sockets[old_alloc].output); 545 } 546 547 void 548 prepare_select(fd_set *readset, fd_set *writeset) 549 { 550 unsigned int i; 551 for (i = 0; i < sockets_alloc; i++) 552 switch (sockets[i].type) { 553 case AUTH_SOCKET: 554 case AUTH_CONNECTION: 555 FD_SET(sockets[i].fd, readset); 556 if (buffer_len(&sockets[i].output) > 0) 557 FD_SET(sockets[i].fd, writeset); 558 break; 559 case AUTH_UNUSED: 560 break; 561 default: 562 fatal("Unknown socket type %d", sockets[i].type); 563 break; 564 } 565 } 566 567 void 568 after_select(fd_set *readset, fd_set *writeset) 569 { 570 unsigned int i; 571 int len, sock; 572 socklen_t slen; 573 char buf[1024]; 574 struct sockaddr_un sunaddr; 575 576 for (i = 0; i < sockets_alloc; i++) 577 switch (sockets[i].type) { 578 case AUTH_UNUSED: 579 break; 580 case AUTH_SOCKET: 581 if (FD_ISSET(sockets[i].fd, readset)) { 582 slen = sizeof(sunaddr); 583 sock = accept(sockets[i].fd, (struct sockaddr *) & sunaddr, &slen); 584 if (sock < 0) { 585 perror("accept from AUTH_SOCKET"); 586 break; 587 } 588 new_socket(AUTH_CONNECTION, sock); 589 } 590 break; 591 case AUTH_CONNECTION: 592 if (buffer_len(&sockets[i].output) > 0 && 593 FD_ISSET(sockets[i].fd, writeset)) { 594 len = write(sockets[i].fd, buffer_ptr(&sockets[i].output), 595 buffer_len(&sockets[i].output)); 596 if (len <= 0) { 597 shutdown(sockets[i].fd, SHUT_RDWR); 598 close(sockets[i].fd); 599 sockets[i].type = AUTH_UNUSED; 600 buffer_free(&sockets[i].input); 601 buffer_free(&sockets[i].output); 602 break; 603 } 604 buffer_consume(&sockets[i].output, len); 605 } 606 if (FD_ISSET(sockets[i].fd, readset)) { 607 len = read(sockets[i].fd, buf, sizeof(buf)); 608 if (len <= 0) { 609 shutdown(sockets[i].fd, SHUT_RDWR); 610 close(sockets[i].fd); 611 sockets[i].type = AUTH_UNUSED; 612 buffer_free(&sockets[i].input); 613 buffer_free(&sockets[i].output); 614 break; 615 } 616 buffer_append(&sockets[i].input, buf, len); 617 process_message(&sockets[i]); 618 } 619 break; 620 default: 621 fatal("Unknown type %d", sockets[i].type); 622 } 623 } 624 625 void 626 check_parent_exists(int sig) 627 { 628 if (parent_pid != -1 && kill(parent_pid, 0) < 0) { 629 /* printf("Parent has died - Authentication agent exiting.\n"); */ 630 exit(1); 631 } 632 signal(SIGALRM, check_parent_exists); 633 alarm(10); 634 } 635 636 void 637 cleanup_socket(void) 638 { 639 remove(socket_name); 640 rmdir(socket_dir); 641 } 642 643 void 644 cleanup_exit(int i) 645 { 646 cleanup_socket(); 647 exit(i); 648 } 649 650 void 651 usage() 652 { 653 fprintf(stderr, "ssh-agent version %s\n", SSH_VERSION); 654 fprintf(stderr, "Usage: %s [-c | -s] [-k] [command {args...]]\n", 655 __progname); 656 exit(1); 657 } 658 659 int 660 main(int ac, char **av) 661 { 662 fd_set readset, writeset; 663 int sock, c_flag = 0, k_flag = 0, s_flag = 0, ch; 664 struct sockaddr_un sunaddr; 665 pid_t pid; 666 char *shell, *format, *pidstr, pidstrbuf[1 + 3 * sizeof pid]; 667 668 /* check if RSA support exists */ 669 if (rsa_alive() == 0) { 670 fprintf(stderr, 671 "%s: no RSA support in libssl and libcrypto. See ssl(8).\n", 672 __progname); 673 exit(1); 674 } 675 while ((ch = getopt(ac, av, "cks")) != -1) { 676 switch (ch) { 677 case 'c': 678 if (s_flag) 679 usage(); 680 c_flag++; 681 break; 682 case 'k': 683 k_flag++; 684 break; 685 case 's': 686 if (c_flag) 687 usage(); 688 s_flag++; 689 break; 690 default: 691 usage(); 692 } 693 } 694 ac -= optind; 695 av += optind; 696 697 if (ac > 0 && (c_flag || k_flag || s_flag)) 698 usage(); 699 700 if (ac == 0 && !c_flag && !k_flag && !s_flag) { 701 shell = getenv("SHELL"); 702 if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0) 703 c_flag = 1; 704 } 705 if (k_flag) { 706 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 707 if (pidstr == NULL) { 708 fprintf(stderr, "%s not set, cannot kill agent\n", 709 SSH_AGENTPID_ENV_NAME); 710 exit(1); 711 } 712 pid = atoi(pidstr); 713 if (pid < 1) { /* XXX PID_MAX check too */ 714 /* Yes, PID_MAX check please */ 715 fprintf(stderr, "%s=\"%s\", which is not a good PID\n", 716 SSH_AGENTPID_ENV_NAME, pidstr); 717 exit(1); 718 } 719 if (kill(pid, SIGTERM) == -1) { 720 perror("kill"); 721 exit(1); 722 } 723 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 724 printf(format, SSH_AUTHSOCKET_ENV_NAME); 725 printf(format, SSH_AGENTPID_ENV_NAME); 726 printf("echo Agent pid %d killed;\n", pid); 727 exit(0); 728 } 729 parent_pid = getpid(); 730 731 /* Create private directory for agent socket */ 732 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXX", sizeof socket_dir); 733 if (mkdtemp(socket_dir) == NULL) { 734 perror("mkdtemp: private socket dir"); 735 exit(1); 736 } 737 snprintf(socket_name, sizeof socket_name, "%s/agent.%d", socket_dir, 738 parent_pid); 739 740 /* 741 * Create socket early so it will exist before command gets run from 742 * the parent. 743 */ 744 sock = socket(AF_UNIX, SOCK_STREAM, 0); 745 if (sock < 0) { 746 perror("socket"); 747 cleanup_exit(1); 748 } 749 memset(&sunaddr, 0, sizeof(sunaddr)); 750 sunaddr.sun_family = AF_UNIX; 751 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); 752 sunaddr.sun_len = SUN_LEN(&sunaddr) + 1; 753 if (bind(sock, (struct sockaddr *)&sunaddr, sunaddr.sun_len) < 0) { 754 perror("bind"); 755 cleanup_exit(1); 756 } 757 if (listen(sock, 5) < 0) { 758 perror("listen"); 759 cleanup_exit(1); 760 } 761 /* 762 * Fork, and have the parent execute the command, if any, or present 763 * the socket data. The child continues as the authentication agent. 764 */ 765 pid = fork(); 766 if (pid == -1) { 767 perror("fork"); 768 exit(1); 769 } 770 if (pid != 0) { /* Parent - execute the given command. */ 771 close(sock); 772 snprintf(pidstrbuf, sizeof pidstrbuf, "%d", pid); 773 if (ac == 0) { 774 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 775 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 776 SSH_AUTHSOCKET_ENV_NAME); 777 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 778 SSH_AGENTPID_ENV_NAME); 779 printf("echo Agent pid %d;\n", pid); 780 exit(0); 781 } 782 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 783 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 784 perror("setenv"); 785 exit(1); 786 } 787 execvp(av[0], av); 788 perror(av[0]); 789 exit(1); 790 } 791 close(0); 792 close(1); 793 close(2); 794 795 if (setsid() == -1) { 796 perror("setsid"); 797 cleanup_exit(1); 798 } 799 if (atexit(cleanup_socket) < 0) { 800 perror("atexit"); 801 cleanup_exit(1); 802 } 803 new_socket(AUTH_SOCKET, sock); 804 if (ac > 0) { 805 signal(SIGALRM, check_parent_exists); 806 alarm(10); 807 } 808 idtab_init(); 809 signal(SIGINT, SIG_IGN); 810 signal(SIGPIPE, SIG_IGN); 811 signal(SIGHUP, cleanup_exit); 812 signal(SIGTERM, cleanup_exit); 813 while (1) { 814 FD_ZERO(&readset); 815 FD_ZERO(&writeset); 816 prepare_select(&readset, &writeset); 817 if (select(max_fd + 1, &readset, &writeset, NULL, NULL) < 0) { 818 if (errno == EINTR) 819 continue; 820 exit(1); 821 } 822 after_select(&readset, &writeset); 823 } 824 /* NOTREACHED */ 825 } 826