1 /* $OpenBSD: ssh-agent.c,v 1.184 2014/03/15 17:28:26 deraadt Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * The authentication agent program. 7 * 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". 13 * 14 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 15 * 16 * Redistribution and use in source and binary forms, with or without 17 * modification, are permitted provided that the following conditions 18 * are met: 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. 24 * 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. 35 */ 36 37 #include <sys/types.h> 38 #include <sys/time.h> 39 #include <sys/queue.h> 40 #include <sys/resource.h> 41 #include <sys/types.h> 42 #include <sys/socket.h> 43 #include <sys/un.h> 44 #include <sys/param.h> 45 46 #include <openssl/evp.h> 47 48 #include <errno.h> 49 #include <fcntl.h> 50 #include <paths.h> 51 #include <signal.h> 52 #include <stdlib.h> 53 #include <stdio.h> 54 #include <string.h> 55 #include <time.h> 56 #include <unistd.h> 57 58 #include "xmalloc.h" 59 #include "ssh.h" 60 #include "rsa.h" 61 #include "buffer.h" 62 #include "key.h" 63 #include "authfd.h" 64 #include "compat.h" 65 #include "log.h" 66 #include "misc.h" 67 #include "digest.h" 68 69 #ifdef ENABLE_PKCS11 70 #include "ssh-pkcs11.h" 71 #endif 72 73 typedef enum { 74 AUTH_UNUSED, 75 AUTH_SOCKET, 76 AUTH_CONNECTION 77 } sock_type; 78 79 typedef struct { 80 int fd; 81 sock_type type; 82 Buffer input; 83 Buffer output; 84 Buffer request; 85 } SocketEntry; 86 87 u_int sockets_alloc = 0; 88 SocketEntry *sockets = NULL; 89 90 typedef struct identity { 91 TAILQ_ENTRY(identity) next; 92 Key *key; 93 char *comment; 94 char *provider; 95 time_t death; 96 u_int confirm; 97 } Identity; 98 99 typedef struct { 100 int nentries; 101 TAILQ_HEAD(idqueue, identity) idlist; 102 } Idtab; 103 104 /* private key table, one per protocol version */ 105 Idtab idtable[3]; 106 107 int max_fd = 0; 108 109 /* pid of shell == parent of agent */ 110 pid_t parent_pid = -1; 111 time_t parent_alive_interval = 0; 112 113 /* pathname and directory for AUTH_SOCKET */ 114 char socket_name[MAXPATHLEN]; 115 char socket_dir[MAXPATHLEN]; 116 117 /* locking */ 118 int locked = 0; 119 char *lock_passwd = NULL; 120 121 extern char *__progname; 122 123 /* Default lifetime in seconds (0 == forever) */ 124 static long lifetime = 0; 125 126 static void 127 close_socket(SocketEntry *e) 128 { 129 close(e->fd); 130 e->fd = -1; 131 e->type = AUTH_UNUSED; 132 buffer_free(&e->input); 133 buffer_free(&e->output); 134 buffer_free(&e->request); 135 } 136 137 static void 138 idtab_init(void) 139 { 140 int i; 141 142 for (i = 0; i <=2; i++) { 143 TAILQ_INIT(&idtable[i].idlist); 144 idtable[i].nentries = 0; 145 } 146 } 147 148 /* return private key table for requested protocol version */ 149 static Idtab * 150 idtab_lookup(int version) 151 { 152 if (version < 1 || version > 2) 153 fatal("internal error, bad protocol version %d", version); 154 return &idtable[version]; 155 } 156 157 static void 158 free_identity(Identity *id) 159 { 160 key_free(id->key); 161 free(id->provider); 162 free(id->comment); 163 free(id); 164 } 165 166 /* return matching private key for given public key */ 167 static Identity * 168 lookup_identity(Key *key, int version) 169 { 170 Identity *id; 171 172 Idtab *tab = idtab_lookup(version); 173 TAILQ_FOREACH(id, &tab->idlist, next) { 174 if (key_equal(key, id->key)) 175 return (id); 176 } 177 return (NULL); 178 } 179 180 /* Check confirmation of keysign request */ 181 static int 182 confirm_key(Identity *id) 183 { 184 char *p; 185 int ret = -1; 186 187 p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX); 188 if (ask_permission("Allow use of key %s?\nKey fingerprint %s.", 189 id->comment, p)) 190 ret = 0; 191 free(p); 192 193 return (ret); 194 } 195 196 /* send list of supported public keys to 'client' */ 197 static void 198 process_request_identities(SocketEntry *e, int version) 199 { 200 Idtab *tab = idtab_lookup(version); 201 Identity *id; 202 Buffer msg; 203 204 buffer_init(&msg); 205 buffer_put_char(&msg, (version == 1) ? 206 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 207 buffer_put_int(&msg, tab->nentries); 208 TAILQ_FOREACH(id, &tab->idlist, next) { 209 if (id->key->type == KEY_RSA1) { 210 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n)); 211 buffer_put_bignum(&msg, id->key->rsa->e); 212 buffer_put_bignum(&msg, id->key->rsa->n); 213 } else { 214 u_char *blob; 215 u_int blen; 216 key_to_blob(id->key, &blob, &blen); 217 buffer_put_string(&msg, blob, blen); 218 free(blob); 219 } 220 buffer_put_cstring(&msg, id->comment); 221 } 222 buffer_put_int(&e->output, buffer_len(&msg)); 223 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 224 buffer_free(&msg); 225 } 226 227 /* ssh1 only */ 228 static void 229 process_authentication_challenge1(SocketEntry *e) 230 { 231 u_char buf[32], mdbuf[16], session_id[16]; 232 u_int response_type; 233 BIGNUM *challenge; 234 Identity *id; 235 int i, len; 236 Buffer msg; 237 struct ssh_digest_ctx *md; 238 Key *key; 239 240 buffer_init(&msg); 241 key = key_new(KEY_RSA1); 242 if ((challenge = BN_new()) == NULL) 243 fatal("process_authentication_challenge1: BN_new failed"); 244 245 (void) buffer_get_int(&e->request); /* ignored */ 246 buffer_get_bignum(&e->request, key->rsa->e); 247 buffer_get_bignum(&e->request, key->rsa->n); 248 buffer_get_bignum(&e->request, challenge); 249 250 /* Only protocol 1.1 is supported */ 251 if (buffer_len(&e->request) == 0) 252 goto failure; 253 buffer_get(&e->request, session_id, 16); 254 response_type = buffer_get_int(&e->request); 255 if (response_type != 1) 256 goto failure; 257 258 id = lookup_identity(key, 1); 259 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) { 260 Key *private = id->key; 261 /* Decrypt the challenge using the private key. */ 262 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0) 263 goto failure; 264 265 /* The response is MD5 of decrypted challenge plus session id. */ 266 len = BN_num_bytes(challenge); 267 if (len <= 0 || len > 32) { 268 logit("process_authentication_challenge: bad challenge length %d", len); 269 goto failure; 270 } 271 memset(buf, 0, 32); 272 BN_bn2bin(challenge, buf + 32 - len); 273 if ((md = ssh_digest_start(SSH_DIGEST_MD5)) == NULL || 274 ssh_digest_update(md, buf, 32) < 0 || 275 ssh_digest_update(md, session_id, 16) < 0 || 276 ssh_digest_final(md, mdbuf, sizeof(mdbuf)) < 0) 277 fatal("%s: md5 failed", __func__); 278 ssh_digest_free(md); 279 280 /* Send the response. */ 281 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE); 282 for (i = 0; i < 16; i++) 283 buffer_put_char(&msg, mdbuf[i]); 284 goto send; 285 } 286 287 failure: 288 /* Unknown identity or protocol error. Send failure. */ 289 buffer_put_char(&msg, SSH_AGENT_FAILURE); 290 send: 291 buffer_put_int(&e->output, buffer_len(&msg)); 292 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 293 key_free(key); 294 BN_clear_free(challenge); 295 buffer_free(&msg); 296 } 297 298 /* ssh2 only */ 299 static void 300 process_sign_request2(SocketEntry *e) 301 { 302 u_char *blob, *data, *signature = NULL; 303 u_int blen, dlen, slen = 0; 304 extern int datafellows; 305 int odatafellows; 306 int ok = -1, flags; 307 Buffer msg; 308 Key *key; 309 310 datafellows = 0; 311 312 blob = buffer_get_string(&e->request, &blen); 313 data = buffer_get_string(&e->request, &dlen); 314 315 flags = buffer_get_int(&e->request); 316 odatafellows = datafellows; 317 if (flags & SSH_AGENT_OLD_SIGNATURE) 318 datafellows = SSH_BUG_SIGBLOB; 319 320 key = key_from_blob(blob, blen); 321 if (key != NULL) { 322 Identity *id = lookup_identity(key, 2); 323 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) 324 ok = key_sign(id->key, &signature, &slen, data, dlen); 325 key_free(key); 326 } 327 buffer_init(&msg); 328 if (ok == 0) { 329 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); 330 buffer_put_string(&msg, signature, slen); 331 } else { 332 buffer_put_char(&msg, SSH_AGENT_FAILURE); 333 } 334 buffer_put_int(&e->output, buffer_len(&msg)); 335 buffer_append(&e->output, buffer_ptr(&msg), 336 buffer_len(&msg)); 337 buffer_free(&msg); 338 free(data); 339 free(blob); 340 free(signature); 341 datafellows = odatafellows; 342 } 343 344 /* shared */ 345 static void 346 process_remove_identity(SocketEntry *e, int version) 347 { 348 u_int blen, bits; 349 int success = 0; 350 Key *key = NULL; 351 u_char *blob; 352 353 switch (version) { 354 case 1: 355 key = key_new(KEY_RSA1); 356 bits = buffer_get_int(&e->request); 357 buffer_get_bignum(&e->request, key->rsa->e); 358 buffer_get_bignum(&e->request, key->rsa->n); 359 360 if (bits != key_size(key)) 361 logit("Warning: identity keysize mismatch: actual %u, announced %u", 362 key_size(key), bits); 363 break; 364 case 2: 365 blob = buffer_get_string(&e->request, &blen); 366 key = key_from_blob(blob, blen); 367 free(blob); 368 break; 369 } 370 if (key != NULL) { 371 Identity *id = lookup_identity(key, version); 372 if (id != NULL) { 373 /* 374 * We have this key. Free the old key. Since we 375 * don't want to leave empty slots in the middle of 376 * the array, we actually free the key there and move 377 * all the entries between the empty slot and the end 378 * of the array. 379 */ 380 Idtab *tab = idtab_lookup(version); 381 if (tab->nentries < 1) 382 fatal("process_remove_identity: " 383 "internal error: tab->nentries %d", 384 tab->nentries); 385 TAILQ_REMOVE(&tab->idlist, id, next); 386 free_identity(id); 387 tab->nentries--; 388 success = 1; 389 } 390 key_free(key); 391 } 392 buffer_put_int(&e->output, 1); 393 buffer_put_char(&e->output, 394 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 395 } 396 397 static void 398 process_remove_all_identities(SocketEntry *e, int version) 399 { 400 Idtab *tab = idtab_lookup(version); 401 Identity *id; 402 403 /* Loop over all identities and clear the keys. */ 404 for (id = TAILQ_FIRST(&tab->idlist); id; 405 id = TAILQ_FIRST(&tab->idlist)) { 406 TAILQ_REMOVE(&tab->idlist, id, next); 407 free_identity(id); 408 } 409 410 /* Mark that there are no identities. */ 411 tab->nentries = 0; 412 413 /* Send success. */ 414 buffer_put_int(&e->output, 1); 415 buffer_put_char(&e->output, SSH_AGENT_SUCCESS); 416 } 417 418 /* removes expired keys and returns number of seconds until the next expiry */ 419 static time_t 420 reaper(void) 421 { 422 time_t deadline = 0, now = monotime(); 423 Identity *id, *nxt; 424 int version; 425 Idtab *tab; 426 427 for (version = 1; version < 3; version++) { 428 tab = idtab_lookup(version); 429 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 430 nxt = TAILQ_NEXT(id, next); 431 if (id->death == 0) 432 continue; 433 if (now >= id->death) { 434 debug("expiring key '%s'", id->comment); 435 TAILQ_REMOVE(&tab->idlist, id, next); 436 free_identity(id); 437 tab->nentries--; 438 } else 439 deadline = (deadline == 0) ? id->death : 440 MIN(deadline, id->death); 441 } 442 } 443 if (deadline == 0 || deadline <= now) 444 return 0; 445 else 446 return (deadline - now); 447 } 448 449 static void 450 process_add_identity(SocketEntry *e, int version) 451 { 452 Idtab *tab = idtab_lookup(version); 453 Identity *id; 454 int type, success = 0, confirm = 0; 455 char *comment; 456 time_t death = 0; 457 Key *k = NULL; 458 459 switch (version) { 460 case 1: 461 k = key_new_private(KEY_RSA1); 462 (void) buffer_get_int(&e->request); /* ignored */ 463 buffer_get_bignum(&e->request, k->rsa->n); 464 buffer_get_bignum(&e->request, k->rsa->e); 465 buffer_get_bignum(&e->request, k->rsa->d); 466 buffer_get_bignum(&e->request, k->rsa->iqmp); 467 468 /* SSH and SSL have p and q swapped */ 469 buffer_get_bignum(&e->request, k->rsa->q); /* p */ 470 buffer_get_bignum(&e->request, k->rsa->p); /* q */ 471 472 /* Generate additional parameters */ 473 rsa_generate_additional_parameters(k->rsa); 474 475 /* enable blinding */ 476 if (RSA_blinding_on(k->rsa, NULL) != 1) { 477 error("process_add_identity: RSA_blinding_on failed"); 478 key_free(k); 479 goto send; 480 } 481 break; 482 case 2: 483 k = key_private_deserialize(&e->request); 484 if (k == NULL) { 485 buffer_clear(&e->request); 486 goto send; 487 } 488 break; 489 } 490 comment = buffer_get_string(&e->request, NULL); 491 if (k == NULL) { 492 free(comment); 493 goto send; 494 } 495 while (buffer_len(&e->request)) { 496 switch ((type = buffer_get_char(&e->request))) { 497 case SSH_AGENT_CONSTRAIN_LIFETIME: 498 death = monotime() + buffer_get_int(&e->request); 499 break; 500 case SSH_AGENT_CONSTRAIN_CONFIRM: 501 confirm = 1; 502 break; 503 default: 504 error("process_add_identity: " 505 "Unknown constraint type %d", type); 506 free(comment); 507 key_free(k); 508 goto send; 509 } 510 } 511 success = 1; 512 if (lifetime && !death) 513 death = monotime() + lifetime; 514 if ((id = lookup_identity(k, version)) == NULL) { 515 id = xcalloc(1, sizeof(Identity)); 516 id->key = k; 517 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 518 /* Increment the number of identities. */ 519 tab->nentries++; 520 } else { 521 key_free(k); 522 free(id->comment); 523 } 524 id->comment = comment; 525 id->death = death; 526 id->confirm = confirm; 527 send: 528 buffer_put_int(&e->output, 1); 529 buffer_put_char(&e->output, 530 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 531 } 532 533 /* XXX todo: encrypt sensitive data with passphrase */ 534 static void 535 process_lock_agent(SocketEntry *e, int lock) 536 { 537 int success = 0; 538 char *passwd; 539 540 passwd = buffer_get_string(&e->request, NULL); 541 if (locked && !lock && strcmp(passwd, lock_passwd) == 0) { 542 locked = 0; 543 explicit_bzero(lock_passwd, strlen(lock_passwd)); 544 free(lock_passwd); 545 lock_passwd = NULL; 546 success = 1; 547 } else if (!locked && lock) { 548 locked = 1; 549 lock_passwd = xstrdup(passwd); 550 success = 1; 551 } 552 explicit_bzero(passwd, strlen(passwd)); 553 free(passwd); 554 555 buffer_put_int(&e->output, 1); 556 buffer_put_char(&e->output, 557 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 558 } 559 560 static void 561 no_identities(SocketEntry *e, u_int type) 562 { 563 Buffer msg; 564 565 buffer_init(&msg); 566 buffer_put_char(&msg, 567 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ? 568 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 569 buffer_put_int(&msg, 0); 570 buffer_put_int(&e->output, buffer_len(&msg)); 571 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 572 buffer_free(&msg); 573 } 574 575 #ifdef ENABLE_PKCS11 576 static void 577 process_add_smartcard_key(SocketEntry *e) 578 { 579 char *provider = NULL, *pin; 580 int i, type, version, count = 0, success = 0, confirm = 0; 581 time_t death = 0; 582 Key **keys = NULL, *k; 583 Identity *id; 584 Idtab *tab; 585 586 provider = buffer_get_string(&e->request, NULL); 587 pin = buffer_get_string(&e->request, NULL); 588 589 while (buffer_len(&e->request)) { 590 switch ((type = buffer_get_char(&e->request))) { 591 case SSH_AGENT_CONSTRAIN_LIFETIME: 592 death = monotime() + buffer_get_int(&e->request); 593 break; 594 case SSH_AGENT_CONSTRAIN_CONFIRM: 595 confirm = 1; 596 break; 597 default: 598 error("process_add_smartcard_key: " 599 "Unknown constraint type %d", type); 600 goto send; 601 } 602 } 603 if (lifetime && !death) 604 death = monotime() + lifetime; 605 606 count = pkcs11_add_provider(provider, pin, &keys); 607 for (i = 0; i < count; i++) { 608 k = keys[i]; 609 version = k->type == KEY_RSA1 ? 1 : 2; 610 tab = idtab_lookup(version); 611 if (lookup_identity(k, version) == NULL) { 612 id = xcalloc(1, sizeof(Identity)); 613 id->key = k; 614 id->provider = xstrdup(provider); 615 id->comment = xstrdup(provider); /* XXX */ 616 id->death = death; 617 id->confirm = confirm; 618 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 619 tab->nentries++; 620 success = 1; 621 } else { 622 key_free(k); 623 } 624 keys[i] = NULL; 625 } 626 send: 627 free(pin); 628 free(provider); 629 free(keys); 630 buffer_put_int(&e->output, 1); 631 buffer_put_char(&e->output, 632 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 633 } 634 635 static void 636 process_remove_smartcard_key(SocketEntry *e) 637 { 638 char *provider = NULL, *pin = NULL; 639 int version, success = 0; 640 Identity *id, *nxt; 641 Idtab *tab; 642 643 provider = buffer_get_string(&e->request, NULL); 644 pin = buffer_get_string(&e->request, NULL); 645 free(pin); 646 647 for (version = 1; version < 3; version++) { 648 tab = idtab_lookup(version); 649 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 650 nxt = TAILQ_NEXT(id, next); 651 /* Skip file--based keys */ 652 if (id->provider == NULL) 653 continue; 654 if (!strcmp(provider, id->provider)) { 655 TAILQ_REMOVE(&tab->idlist, id, next); 656 free_identity(id); 657 tab->nentries--; 658 } 659 } 660 } 661 if (pkcs11_del_provider(provider) == 0) 662 success = 1; 663 else 664 error("process_remove_smartcard_key:" 665 " pkcs11_del_provider failed"); 666 free(provider); 667 buffer_put_int(&e->output, 1); 668 buffer_put_char(&e->output, 669 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 670 } 671 #endif /* ENABLE_PKCS11 */ 672 673 /* dispatch incoming messages */ 674 675 static void 676 process_message(SocketEntry *e) 677 { 678 u_int msg_len, type; 679 u_char *cp; 680 681 if (buffer_len(&e->input) < 5) 682 return; /* Incomplete message. */ 683 cp = buffer_ptr(&e->input); 684 msg_len = get_u32(cp); 685 if (msg_len > 256 * 1024) { 686 close_socket(e); 687 return; 688 } 689 if (buffer_len(&e->input) < msg_len + 4) 690 return; 691 692 /* move the current input to e->request */ 693 buffer_consume(&e->input, 4); 694 buffer_clear(&e->request); 695 buffer_append(&e->request, buffer_ptr(&e->input), msg_len); 696 buffer_consume(&e->input, msg_len); 697 type = buffer_get_char(&e->request); 698 699 /* check wheter agent is locked */ 700 if (locked && type != SSH_AGENTC_UNLOCK) { 701 buffer_clear(&e->request); 702 switch (type) { 703 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 704 case SSH2_AGENTC_REQUEST_IDENTITIES: 705 /* send empty lists */ 706 no_identities(e, type); 707 break; 708 default: 709 /* send a fail message for all other request types */ 710 buffer_put_int(&e->output, 1); 711 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 712 } 713 return; 714 } 715 716 debug("type %d", type); 717 switch (type) { 718 case SSH_AGENTC_LOCK: 719 case SSH_AGENTC_UNLOCK: 720 process_lock_agent(e, type == SSH_AGENTC_LOCK); 721 break; 722 /* ssh1 */ 723 case SSH_AGENTC_RSA_CHALLENGE: 724 process_authentication_challenge1(e); 725 break; 726 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 727 process_request_identities(e, 1); 728 break; 729 case SSH_AGENTC_ADD_RSA_IDENTITY: 730 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 731 process_add_identity(e, 1); 732 break; 733 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 734 process_remove_identity(e, 1); 735 break; 736 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 737 process_remove_all_identities(e, 1); 738 break; 739 /* ssh2 */ 740 case SSH2_AGENTC_SIGN_REQUEST: 741 process_sign_request2(e); 742 break; 743 case SSH2_AGENTC_REQUEST_IDENTITIES: 744 process_request_identities(e, 2); 745 break; 746 case SSH2_AGENTC_ADD_IDENTITY: 747 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 748 process_add_identity(e, 2); 749 break; 750 case SSH2_AGENTC_REMOVE_IDENTITY: 751 process_remove_identity(e, 2); 752 break; 753 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 754 process_remove_all_identities(e, 2); 755 break; 756 #ifdef ENABLE_PKCS11 757 case SSH_AGENTC_ADD_SMARTCARD_KEY: 758 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 759 process_add_smartcard_key(e); 760 break; 761 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 762 process_remove_smartcard_key(e); 763 break; 764 #endif /* ENABLE_PKCS11 */ 765 default: 766 /* Unknown message. Respond with failure. */ 767 error("Unknown message %d", type); 768 buffer_clear(&e->request); 769 buffer_put_int(&e->output, 1); 770 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 771 break; 772 } 773 } 774 775 static void 776 new_socket(sock_type type, int fd) 777 { 778 u_int i, old_alloc, new_alloc; 779 780 set_nonblock(fd); 781 782 if (fd > max_fd) 783 max_fd = fd; 784 785 for (i = 0; i < sockets_alloc; i++) 786 if (sockets[i].type == AUTH_UNUSED) { 787 sockets[i].fd = fd; 788 buffer_init(&sockets[i].input); 789 buffer_init(&sockets[i].output); 790 buffer_init(&sockets[i].request); 791 sockets[i].type = type; 792 return; 793 } 794 old_alloc = sockets_alloc; 795 new_alloc = sockets_alloc + 10; 796 sockets = xrealloc(sockets, new_alloc, sizeof(sockets[0])); 797 for (i = old_alloc; i < new_alloc; i++) 798 sockets[i].type = AUTH_UNUSED; 799 sockets_alloc = new_alloc; 800 sockets[old_alloc].fd = fd; 801 buffer_init(&sockets[old_alloc].input); 802 buffer_init(&sockets[old_alloc].output); 803 buffer_init(&sockets[old_alloc].request); 804 sockets[old_alloc].type = type; 805 } 806 807 static int 808 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp, 809 struct timeval **tvpp) 810 { 811 u_int i, sz; 812 int n = 0; 813 static struct timeval tv; 814 time_t deadline; 815 816 for (i = 0; i < sockets_alloc; i++) { 817 switch (sockets[i].type) { 818 case AUTH_SOCKET: 819 case AUTH_CONNECTION: 820 n = MAX(n, sockets[i].fd); 821 break; 822 case AUTH_UNUSED: 823 break; 824 default: 825 fatal("Unknown socket type %d", sockets[i].type); 826 break; 827 } 828 } 829 830 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 831 if (*fdrp == NULL || sz > *nallocp) { 832 free(*fdrp); 833 free(*fdwp); 834 *fdrp = xmalloc(sz); 835 *fdwp = xmalloc(sz); 836 *nallocp = sz; 837 } 838 if (n < *fdl) 839 debug("XXX shrink: %d < %d", n, *fdl); 840 *fdl = n; 841 memset(*fdrp, 0, sz); 842 memset(*fdwp, 0, sz); 843 844 for (i = 0; i < sockets_alloc; i++) { 845 switch (sockets[i].type) { 846 case AUTH_SOCKET: 847 case AUTH_CONNECTION: 848 FD_SET(sockets[i].fd, *fdrp); 849 if (buffer_len(&sockets[i].output) > 0) 850 FD_SET(sockets[i].fd, *fdwp); 851 break; 852 default: 853 break; 854 } 855 } 856 deadline = reaper(); 857 if (parent_alive_interval != 0) 858 deadline = (deadline == 0) ? parent_alive_interval : 859 MIN(deadline, parent_alive_interval); 860 if (deadline == 0) { 861 *tvpp = NULL; 862 } else { 863 tv.tv_sec = deadline; 864 tv.tv_usec = 0; 865 *tvpp = &tv; 866 } 867 return (1); 868 } 869 870 static void 871 after_select(fd_set *readset, fd_set *writeset) 872 { 873 struct sockaddr_un sunaddr; 874 socklen_t slen; 875 char buf[1024]; 876 int len, sock; 877 u_int i, orig_alloc; 878 uid_t euid; 879 gid_t egid; 880 881 for (i = 0, orig_alloc = sockets_alloc; i < orig_alloc; i++) 882 switch (sockets[i].type) { 883 case AUTH_UNUSED: 884 break; 885 case AUTH_SOCKET: 886 if (FD_ISSET(sockets[i].fd, readset)) { 887 slen = sizeof(sunaddr); 888 sock = accept(sockets[i].fd, 889 (struct sockaddr *)&sunaddr, &slen); 890 if (sock < 0) { 891 error("accept from AUTH_SOCKET: %s", 892 strerror(errno)); 893 break; 894 } 895 if (getpeereid(sock, &euid, &egid) < 0) { 896 error("getpeereid %d failed: %s", 897 sock, strerror(errno)); 898 close(sock); 899 break; 900 } 901 if ((euid != 0) && (getuid() != euid)) { 902 error("uid mismatch: " 903 "peer euid %u != uid %u", 904 (u_int) euid, (u_int) getuid()); 905 close(sock); 906 break; 907 } 908 new_socket(AUTH_CONNECTION, sock); 909 } 910 break; 911 case AUTH_CONNECTION: 912 if (buffer_len(&sockets[i].output) > 0 && 913 FD_ISSET(sockets[i].fd, writeset)) { 914 len = write(sockets[i].fd, 915 buffer_ptr(&sockets[i].output), 916 buffer_len(&sockets[i].output)); 917 if (len == -1 && (errno == EAGAIN || 918 errno == EINTR)) 919 continue; 920 if (len <= 0) { 921 close_socket(&sockets[i]); 922 break; 923 } 924 buffer_consume(&sockets[i].output, len); 925 } 926 if (FD_ISSET(sockets[i].fd, readset)) { 927 len = read(sockets[i].fd, buf, sizeof(buf)); 928 if (len == -1 && (errno == EAGAIN || 929 errno == EINTR)) 930 continue; 931 if (len <= 0) { 932 close_socket(&sockets[i]); 933 break; 934 } 935 buffer_append(&sockets[i].input, buf, len); 936 process_message(&sockets[i]); 937 } 938 break; 939 default: 940 fatal("Unknown type %d", sockets[i].type); 941 } 942 } 943 944 static void 945 cleanup_socket(void) 946 { 947 if (socket_name[0]) 948 unlink(socket_name); 949 if (socket_dir[0]) 950 rmdir(socket_dir); 951 } 952 953 void 954 cleanup_exit(int i) 955 { 956 cleanup_socket(); 957 _exit(i); 958 } 959 960 /*ARGSUSED*/ 961 static void 962 cleanup_handler(int sig) 963 { 964 cleanup_socket(); 965 #ifdef ENABLE_PKCS11 966 pkcs11_terminate(); 967 #endif 968 _exit(2); 969 } 970 971 static void 972 check_parent_exists(void) 973 { 974 /* 975 * If our parent has exited then getppid() will return (pid_t)1, 976 * so testing for that should be safe. 977 */ 978 if (parent_pid != -1 && getppid() != parent_pid) { 979 /* printf("Parent has died - Authentication agent exiting.\n"); */ 980 cleanup_socket(); 981 _exit(2); 982 } 983 } 984 985 static void 986 usage(void) 987 { 988 fprintf(stderr, 989 "usage: ssh-agent [-c | -s] [-d] [-a bind_address] [-t life]\n" 990 " [command [arg ...]]\n" 991 " ssh-agent [-c | -s] -k\n"); 992 exit(1); 993 } 994 995 int 996 main(int ac, char **av) 997 { 998 int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0; 999 int sock, fd, ch, result, saved_errno; 1000 u_int nalloc; 1001 char *shell, *format, *pidstr, *agentsocket = NULL; 1002 fd_set *readsetp = NULL, *writesetp = NULL; 1003 struct sockaddr_un sunaddr; 1004 struct rlimit rlim; 1005 extern int optind; 1006 extern char *optarg; 1007 pid_t pid; 1008 char pidstrbuf[1 + 3 * sizeof pid]; 1009 struct timeval *tvp = NULL; 1010 size_t len; 1011 1012 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1013 sanitise_stdfd(); 1014 1015 /* drop */ 1016 setegid(getgid()); 1017 setgid(getgid()); 1018 1019 OpenSSL_add_all_algorithms(); 1020 1021 while ((ch = getopt(ac, av, "cdksa:t:")) != -1) { 1022 switch (ch) { 1023 case 'c': 1024 if (s_flag) 1025 usage(); 1026 c_flag++; 1027 break; 1028 case 'k': 1029 k_flag++; 1030 break; 1031 case 's': 1032 if (c_flag) 1033 usage(); 1034 s_flag++; 1035 break; 1036 case 'd': 1037 if (d_flag) 1038 usage(); 1039 d_flag++; 1040 break; 1041 case 'a': 1042 agentsocket = optarg; 1043 break; 1044 case 't': 1045 if ((lifetime = convtime(optarg)) == -1) { 1046 fprintf(stderr, "Invalid lifetime\n"); 1047 usage(); 1048 } 1049 break; 1050 default: 1051 usage(); 1052 } 1053 } 1054 ac -= optind; 1055 av += optind; 1056 1057 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag)) 1058 usage(); 1059 1060 if (ac == 0 && !c_flag && !s_flag) { 1061 shell = getenv("SHELL"); 1062 if (shell != NULL && (len = strlen(shell)) > 2 && 1063 strncmp(shell + len - 3, "csh", 3) == 0) 1064 c_flag = 1; 1065 } 1066 if (k_flag) { 1067 const char *errstr = NULL; 1068 1069 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1070 if (pidstr == NULL) { 1071 fprintf(stderr, "%s not set, cannot kill agent\n", 1072 SSH_AGENTPID_ENV_NAME); 1073 exit(1); 1074 } 1075 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr); 1076 if (errstr) { 1077 fprintf(stderr, 1078 "%s=\"%s\", which is not a good PID: %s\n", 1079 SSH_AGENTPID_ENV_NAME, pidstr, errstr); 1080 exit(1); 1081 } 1082 if (kill(pid, SIGTERM) == -1) { 1083 perror("kill"); 1084 exit(1); 1085 } 1086 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 1087 printf(format, SSH_AUTHSOCKET_ENV_NAME); 1088 printf(format, SSH_AGENTPID_ENV_NAME); 1089 printf("echo Agent pid %ld killed;\n", (long)pid); 1090 exit(0); 1091 } 1092 parent_pid = getpid(); 1093 1094 if (agentsocket == NULL) { 1095 /* Create private directory for agent socket */ 1096 mktemp_proto(socket_dir, sizeof(socket_dir)); 1097 if (mkdtemp(socket_dir) == NULL) { 1098 perror("mkdtemp: private socket dir"); 1099 exit(1); 1100 } 1101 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1102 (long)parent_pid); 1103 } else { 1104 /* Try to use specified agent socket */ 1105 socket_dir[0] = '\0'; 1106 strlcpy(socket_name, agentsocket, sizeof socket_name); 1107 } 1108 1109 /* 1110 * Create socket early so it will exist before command gets run from 1111 * the parent. 1112 */ 1113 sock = socket(AF_UNIX, SOCK_STREAM, 0); 1114 if (sock < 0) { 1115 perror("socket"); 1116 *socket_name = '\0'; /* Don't unlink any existing file */ 1117 cleanup_exit(1); 1118 } 1119 memset(&sunaddr, 0, sizeof(sunaddr)); 1120 sunaddr.sun_family = AF_UNIX; 1121 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); 1122 if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) { 1123 perror("bind"); 1124 *socket_name = '\0'; /* Don't unlink any existing file */ 1125 cleanup_exit(1); 1126 } 1127 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 1128 perror("listen"); 1129 cleanup_exit(1); 1130 } 1131 1132 /* 1133 * Fork, and have the parent execute the command, if any, or present 1134 * the socket data. The child continues as the authentication agent. 1135 */ 1136 if (d_flag) { 1137 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1); 1138 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1139 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1140 SSH_AUTHSOCKET_ENV_NAME); 1141 printf("echo Agent pid %ld;\n", (long)parent_pid); 1142 goto skip; 1143 } 1144 pid = fork(); 1145 if (pid == -1) { 1146 perror("fork"); 1147 cleanup_exit(1); 1148 } 1149 if (pid != 0) { /* Parent - execute the given command. */ 1150 close(sock); 1151 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1152 if (ac == 0) { 1153 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1154 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1155 SSH_AUTHSOCKET_ENV_NAME); 1156 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 1157 SSH_AGENTPID_ENV_NAME); 1158 printf("echo Agent pid %ld;\n", (long)pid); 1159 exit(0); 1160 } 1161 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1162 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1163 perror("setenv"); 1164 exit(1); 1165 } 1166 execvp(av[0], av); 1167 perror(av[0]); 1168 exit(1); 1169 } 1170 /* child */ 1171 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1172 1173 if (setsid() == -1) { 1174 error("setsid: %s", strerror(errno)); 1175 cleanup_exit(1); 1176 } 1177 1178 (void)chdir("/"); 1179 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1180 /* XXX might close listen socket */ 1181 (void)dup2(fd, STDIN_FILENO); 1182 (void)dup2(fd, STDOUT_FILENO); 1183 (void)dup2(fd, STDERR_FILENO); 1184 if (fd > 2) 1185 close(fd); 1186 } 1187 1188 /* deny core dumps, since memory contains unencrypted private keys */ 1189 rlim.rlim_cur = rlim.rlim_max = 0; 1190 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 1191 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1192 cleanup_exit(1); 1193 } 1194 1195 skip: 1196 1197 #ifdef ENABLE_PKCS11 1198 pkcs11_init(0); 1199 #endif 1200 new_socket(AUTH_SOCKET, sock); 1201 if (ac > 0) 1202 parent_alive_interval = 10; 1203 idtab_init(); 1204 signal(SIGPIPE, SIG_IGN); 1205 signal(SIGINT, d_flag ? cleanup_handler : SIG_IGN); 1206 signal(SIGHUP, cleanup_handler); 1207 signal(SIGTERM, cleanup_handler); 1208 nalloc = 0; 1209 1210 while (1) { 1211 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp); 1212 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp); 1213 saved_errno = errno; 1214 if (parent_alive_interval != 0) 1215 check_parent_exists(); 1216 (void) reaper(); /* remove expired keys */ 1217 if (result < 0) { 1218 if (saved_errno == EINTR) 1219 continue; 1220 fatal("select: %s", strerror(saved_errno)); 1221 } else if (result > 0) 1222 after_select(readsetp, writesetp); 1223 } 1224 /* NOTREACHED */ 1225 } 1226