1 /* $OpenBSD: ssh-agent.c,v 1.191 2014/11/18 20:54:28 krw 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/socket.h> 42 #include <sys/stat.h> 43 #include <sys/un.h> 44 #include <sys/param.h> 45 46 #ifdef WITH_OPENSSL 47 #include <openssl/evp.h> 48 #endif 49 50 #include <errno.h> 51 #include <fcntl.h> 52 #include <paths.h> 53 #include <signal.h> 54 #include <stdlib.h> 55 #include <stdio.h> 56 #include <string.h> 57 #include <time.h> 58 #include <unistd.h> 59 60 #include "xmalloc.h" 61 #include "ssh.h" 62 #include "rsa.h" 63 #include "buffer.h" 64 #include "key.h" 65 #include "authfd.h" 66 #include "compat.h" 67 #include "log.h" 68 #include "misc.h" 69 #include "digest.h" 70 71 #ifdef ENABLE_PKCS11 72 #include "ssh-pkcs11.h" 73 #endif 74 75 typedef enum { 76 AUTH_UNUSED, 77 AUTH_SOCKET, 78 AUTH_CONNECTION 79 } sock_type; 80 81 typedef struct { 82 int fd; 83 sock_type type; 84 Buffer input; 85 Buffer output; 86 Buffer request; 87 } SocketEntry; 88 89 u_int sockets_alloc = 0; 90 SocketEntry *sockets = NULL; 91 92 typedef struct identity { 93 TAILQ_ENTRY(identity) next; 94 Key *key; 95 char *comment; 96 char *provider; 97 time_t death; 98 u_int confirm; 99 } Identity; 100 101 typedef struct { 102 int nentries; 103 TAILQ_HEAD(idqueue, identity) idlist; 104 } Idtab; 105 106 /* private key table, one per protocol version */ 107 Idtab idtable[3]; 108 109 int max_fd = 0; 110 111 /* pid of shell == parent of agent */ 112 pid_t parent_pid = -1; 113 time_t parent_alive_interval = 0; 114 115 /* pid of process for which cleanup_socket is applicable */ 116 pid_t cleanup_pid = 0; 117 118 /* pathname and directory for AUTH_SOCKET */ 119 char socket_name[MAXPATHLEN]; 120 char socket_dir[MAXPATHLEN]; 121 122 /* locking */ 123 int locked = 0; 124 char *lock_passwd = NULL; 125 126 extern char *__progname; 127 128 /* Default lifetime in seconds (0 == forever) */ 129 static long lifetime = 0; 130 131 static void 132 close_socket(SocketEntry *e) 133 { 134 close(e->fd); 135 e->fd = -1; 136 e->type = AUTH_UNUSED; 137 buffer_free(&e->input); 138 buffer_free(&e->output); 139 buffer_free(&e->request); 140 } 141 142 static void 143 idtab_init(void) 144 { 145 int i; 146 147 for (i = 0; i <=2; i++) { 148 TAILQ_INIT(&idtable[i].idlist); 149 idtable[i].nentries = 0; 150 } 151 } 152 153 /* return private key table for requested protocol version */ 154 static Idtab * 155 idtab_lookup(int version) 156 { 157 if (version < 1 || version > 2) 158 fatal("internal error, bad protocol version %d", version); 159 return &idtable[version]; 160 } 161 162 static void 163 free_identity(Identity *id) 164 { 165 key_free(id->key); 166 free(id->provider); 167 free(id->comment); 168 free(id); 169 } 170 171 /* return matching private key for given public key */ 172 static Identity * 173 lookup_identity(Key *key, int version) 174 { 175 Identity *id; 176 177 Idtab *tab = idtab_lookup(version); 178 TAILQ_FOREACH(id, &tab->idlist, next) { 179 if (key_equal(key, id->key)) 180 return (id); 181 } 182 return (NULL); 183 } 184 185 /* Check confirmation of keysign request */ 186 static int 187 confirm_key(Identity *id) 188 { 189 char *p; 190 int ret = -1; 191 192 p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX); 193 if (ask_permission("Allow use of key %s?\nKey fingerprint %s.", 194 id->comment, p)) 195 ret = 0; 196 free(p); 197 198 return (ret); 199 } 200 201 /* send list of supported public keys to 'client' */ 202 static void 203 process_request_identities(SocketEntry *e, int version) 204 { 205 Idtab *tab = idtab_lookup(version); 206 Identity *id; 207 Buffer msg; 208 209 buffer_init(&msg); 210 buffer_put_char(&msg, (version == 1) ? 211 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 212 buffer_put_int(&msg, tab->nentries); 213 TAILQ_FOREACH(id, &tab->idlist, next) { 214 if (id->key->type == KEY_RSA1) { 215 #ifdef WITH_SSH1 216 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n)); 217 buffer_put_bignum(&msg, id->key->rsa->e); 218 buffer_put_bignum(&msg, id->key->rsa->n); 219 #endif 220 } else { 221 u_char *blob; 222 u_int blen; 223 key_to_blob(id->key, &blob, &blen); 224 buffer_put_string(&msg, blob, blen); 225 free(blob); 226 } 227 buffer_put_cstring(&msg, id->comment); 228 } 229 buffer_put_int(&e->output, buffer_len(&msg)); 230 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 231 buffer_free(&msg); 232 } 233 234 #ifdef WITH_SSH1 235 /* ssh1 only */ 236 static void 237 process_authentication_challenge1(SocketEntry *e) 238 { 239 u_char buf[32], mdbuf[16], session_id[16]; 240 u_int response_type; 241 BIGNUM *challenge; 242 Identity *id; 243 int i, len; 244 Buffer msg; 245 struct ssh_digest_ctx *md; 246 Key *key; 247 248 buffer_init(&msg); 249 key = key_new(KEY_RSA1); 250 if ((challenge = BN_new()) == NULL) 251 fatal("process_authentication_challenge1: BN_new failed"); 252 253 (void) buffer_get_int(&e->request); /* ignored */ 254 buffer_get_bignum(&e->request, key->rsa->e); 255 buffer_get_bignum(&e->request, key->rsa->n); 256 buffer_get_bignum(&e->request, challenge); 257 258 /* Only protocol 1.1 is supported */ 259 if (buffer_len(&e->request) == 0) 260 goto failure; 261 buffer_get(&e->request, session_id, 16); 262 response_type = buffer_get_int(&e->request); 263 if (response_type != 1) 264 goto failure; 265 266 id = lookup_identity(key, 1); 267 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) { 268 Key *private = id->key; 269 /* Decrypt the challenge using the private key. */ 270 if (rsa_private_decrypt(challenge, challenge, private->rsa) != 0) 271 goto failure; 272 273 /* The response is MD5 of decrypted challenge plus session id. */ 274 len = BN_num_bytes(challenge); 275 if (len <= 0 || len > 32) { 276 logit("process_authentication_challenge: bad challenge length %d", len); 277 goto failure; 278 } 279 memset(buf, 0, 32); 280 BN_bn2bin(challenge, buf + 32 - len); 281 if ((md = ssh_digest_start(SSH_DIGEST_MD5)) == NULL || 282 ssh_digest_update(md, buf, 32) < 0 || 283 ssh_digest_update(md, session_id, 16) < 0 || 284 ssh_digest_final(md, mdbuf, sizeof(mdbuf)) < 0) 285 fatal("%s: md5 failed", __func__); 286 ssh_digest_free(md); 287 288 /* Send the response. */ 289 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE); 290 for (i = 0; i < 16; i++) 291 buffer_put_char(&msg, mdbuf[i]); 292 goto send; 293 } 294 295 failure: 296 /* Unknown identity or protocol error. Send failure. */ 297 buffer_put_char(&msg, SSH_AGENT_FAILURE); 298 send: 299 buffer_put_int(&e->output, buffer_len(&msg)); 300 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 301 key_free(key); 302 BN_clear_free(challenge); 303 buffer_free(&msg); 304 } 305 #endif 306 307 /* ssh2 only */ 308 static void 309 process_sign_request2(SocketEntry *e) 310 { 311 u_char *blob, *data, *signature = NULL; 312 u_int blen, dlen, slen = 0; 313 extern int datafellows; 314 int odatafellows; 315 int ok = -1, flags; 316 Buffer msg; 317 Key *key; 318 319 datafellows = 0; 320 321 blob = buffer_get_string(&e->request, &blen); 322 data = buffer_get_string(&e->request, &dlen); 323 324 flags = buffer_get_int(&e->request); 325 odatafellows = datafellows; 326 if (flags & SSH_AGENT_OLD_SIGNATURE) 327 datafellows = SSH_BUG_SIGBLOB; 328 329 key = key_from_blob(blob, blen); 330 if (key != NULL) { 331 Identity *id = lookup_identity(key, 2); 332 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) 333 ok = key_sign(id->key, &signature, &slen, data, dlen); 334 key_free(key); 335 } 336 buffer_init(&msg); 337 if (ok == 0) { 338 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); 339 buffer_put_string(&msg, signature, slen); 340 } else { 341 buffer_put_char(&msg, SSH_AGENT_FAILURE); 342 } 343 buffer_put_int(&e->output, buffer_len(&msg)); 344 buffer_append(&e->output, buffer_ptr(&msg), 345 buffer_len(&msg)); 346 buffer_free(&msg); 347 free(data); 348 free(blob); 349 free(signature); 350 datafellows = odatafellows; 351 } 352 353 /* shared */ 354 static void 355 process_remove_identity(SocketEntry *e, int version) 356 { 357 u_int blen; 358 int success = 0; 359 Key *key = NULL; 360 u_char *blob; 361 #ifdef WITH_SSH1 362 u_int bits; 363 #endif /* WITH_SSH1 */ 364 365 switch (version) { 366 #ifdef WITH_SSH1 367 case 1: 368 key = key_new(KEY_RSA1); 369 bits = buffer_get_int(&e->request); 370 buffer_get_bignum(&e->request, key->rsa->e); 371 buffer_get_bignum(&e->request, key->rsa->n); 372 373 if (bits != key_size(key)) 374 logit("Warning: identity keysize mismatch: actual %u, announced %u", 375 key_size(key), bits); 376 break; 377 #endif /* WITH_SSH1 */ 378 case 2: 379 blob = buffer_get_string(&e->request, &blen); 380 key = key_from_blob(blob, blen); 381 free(blob); 382 break; 383 } 384 if (key != NULL) { 385 Identity *id = lookup_identity(key, version); 386 if (id != NULL) { 387 /* 388 * We have this key. Free the old key. Since we 389 * don't want to leave empty slots in the middle of 390 * the array, we actually free the key there and move 391 * all the entries between the empty slot and the end 392 * of the array. 393 */ 394 Idtab *tab = idtab_lookup(version); 395 if (tab->nentries < 1) 396 fatal("process_remove_identity: " 397 "internal error: tab->nentries %d", 398 tab->nentries); 399 TAILQ_REMOVE(&tab->idlist, id, next); 400 free_identity(id); 401 tab->nentries--; 402 success = 1; 403 } 404 key_free(key); 405 } 406 buffer_put_int(&e->output, 1); 407 buffer_put_char(&e->output, 408 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 409 } 410 411 static void 412 process_remove_all_identities(SocketEntry *e, int version) 413 { 414 Idtab *tab = idtab_lookup(version); 415 Identity *id; 416 417 /* Loop over all identities and clear the keys. */ 418 for (id = TAILQ_FIRST(&tab->idlist); id; 419 id = TAILQ_FIRST(&tab->idlist)) { 420 TAILQ_REMOVE(&tab->idlist, id, next); 421 free_identity(id); 422 } 423 424 /* Mark that there are no identities. */ 425 tab->nentries = 0; 426 427 /* Send success. */ 428 buffer_put_int(&e->output, 1); 429 buffer_put_char(&e->output, SSH_AGENT_SUCCESS); 430 } 431 432 /* removes expired keys and returns number of seconds until the next expiry */ 433 static time_t 434 reaper(void) 435 { 436 time_t deadline = 0, now = monotime(); 437 Identity *id, *nxt; 438 int version; 439 Idtab *tab; 440 441 for (version = 1; version < 3; version++) { 442 tab = idtab_lookup(version); 443 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 444 nxt = TAILQ_NEXT(id, next); 445 if (id->death == 0) 446 continue; 447 if (now >= id->death) { 448 debug("expiring key '%s'", id->comment); 449 TAILQ_REMOVE(&tab->idlist, id, next); 450 free_identity(id); 451 tab->nentries--; 452 } else 453 deadline = (deadline == 0) ? id->death : 454 MIN(deadline, id->death); 455 } 456 } 457 if (deadline == 0 || deadline <= now) 458 return 0; 459 else 460 return (deadline - now); 461 } 462 463 static void 464 process_add_identity(SocketEntry *e, int version) 465 { 466 Idtab *tab = idtab_lookup(version); 467 Identity *id; 468 int type, success = 0, confirm = 0; 469 char *comment; 470 time_t death = 0; 471 Key *k = NULL; 472 473 switch (version) { 474 #ifdef WITH_SSH1 475 case 1: 476 k = key_new_private(KEY_RSA1); 477 (void) buffer_get_int(&e->request); /* ignored */ 478 buffer_get_bignum(&e->request, k->rsa->n); 479 buffer_get_bignum(&e->request, k->rsa->e); 480 buffer_get_bignum(&e->request, k->rsa->d); 481 buffer_get_bignum(&e->request, k->rsa->iqmp); 482 483 /* SSH and SSL have p and q swapped */ 484 buffer_get_bignum(&e->request, k->rsa->q); /* p */ 485 buffer_get_bignum(&e->request, k->rsa->p); /* q */ 486 487 /* Generate additional parameters */ 488 if (rsa_generate_additional_parameters(k->rsa) != 0) 489 fatal("%s: rsa_generate_additional_parameters " 490 "error", __func__); 491 492 /* enable blinding */ 493 if (RSA_blinding_on(k->rsa, NULL) != 1) { 494 error("process_add_identity: RSA_blinding_on failed"); 495 key_free(k); 496 goto send; 497 } 498 break; 499 #endif /* WITH_SSH1 */ 500 case 2: 501 k = key_private_deserialize(&e->request); 502 if (k == NULL) { 503 buffer_clear(&e->request); 504 goto send; 505 } 506 break; 507 } 508 if (k == NULL) 509 goto send; 510 comment = buffer_get_string(&e->request, NULL); 511 512 while (buffer_len(&e->request)) { 513 switch ((type = buffer_get_char(&e->request))) { 514 case SSH_AGENT_CONSTRAIN_LIFETIME: 515 death = monotime() + buffer_get_int(&e->request); 516 break; 517 case SSH_AGENT_CONSTRAIN_CONFIRM: 518 confirm = 1; 519 break; 520 default: 521 error("process_add_identity: " 522 "Unknown constraint type %d", type); 523 free(comment); 524 key_free(k); 525 goto send; 526 } 527 } 528 success = 1; 529 if (lifetime && !death) 530 death = monotime() + lifetime; 531 if ((id = lookup_identity(k, version)) == NULL) { 532 id = xcalloc(1, sizeof(Identity)); 533 id->key = k; 534 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 535 /* Increment the number of identities. */ 536 tab->nentries++; 537 } else { 538 key_free(k); 539 free(id->comment); 540 } 541 id->comment = comment; 542 id->death = death; 543 id->confirm = confirm; 544 send: 545 buffer_put_int(&e->output, 1); 546 buffer_put_char(&e->output, 547 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 548 } 549 550 /* XXX todo: encrypt sensitive data with passphrase */ 551 static void 552 process_lock_agent(SocketEntry *e, int lock) 553 { 554 int success = 0; 555 char *passwd; 556 557 passwd = buffer_get_string(&e->request, NULL); 558 if (locked && !lock && strcmp(passwd, lock_passwd) == 0) { 559 locked = 0; 560 explicit_bzero(lock_passwd, strlen(lock_passwd)); 561 free(lock_passwd); 562 lock_passwd = NULL; 563 success = 1; 564 } else if (!locked && lock) { 565 locked = 1; 566 lock_passwd = xstrdup(passwd); 567 success = 1; 568 } 569 explicit_bzero(passwd, strlen(passwd)); 570 free(passwd); 571 572 buffer_put_int(&e->output, 1); 573 buffer_put_char(&e->output, 574 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 575 } 576 577 static void 578 no_identities(SocketEntry *e, u_int type) 579 { 580 Buffer msg; 581 582 buffer_init(&msg); 583 buffer_put_char(&msg, 584 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ? 585 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 586 buffer_put_int(&msg, 0); 587 buffer_put_int(&e->output, buffer_len(&msg)); 588 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 589 buffer_free(&msg); 590 } 591 592 #ifdef ENABLE_PKCS11 593 static void 594 process_add_smartcard_key(SocketEntry *e) 595 { 596 char *provider = NULL, *pin; 597 int i, type, version, count = 0, success = 0, confirm = 0; 598 time_t death = 0; 599 Key **keys = NULL, *k; 600 Identity *id; 601 Idtab *tab; 602 603 provider = buffer_get_string(&e->request, NULL); 604 pin = buffer_get_string(&e->request, NULL); 605 606 while (buffer_len(&e->request)) { 607 switch ((type = buffer_get_char(&e->request))) { 608 case SSH_AGENT_CONSTRAIN_LIFETIME: 609 death = monotime() + buffer_get_int(&e->request); 610 break; 611 case SSH_AGENT_CONSTRAIN_CONFIRM: 612 confirm = 1; 613 break; 614 default: 615 error("process_add_smartcard_key: " 616 "Unknown constraint type %d", type); 617 goto send; 618 } 619 } 620 if (lifetime && !death) 621 death = monotime() + lifetime; 622 623 count = pkcs11_add_provider(provider, pin, &keys); 624 for (i = 0; i < count; i++) { 625 k = keys[i]; 626 version = k->type == KEY_RSA1 ? 1 : 2; 627 tab = idtab_lookup(version); 628 if (lookup_identity(k, version) == NULL) { 629 id = xcalloc(1, sizeof(Identity)); 630 id->key = k; 631 id->provider = xstrdup(provider); 632 id->comment = xstrdup(provider); /* XXX */ 633 id->death = death; 634 id->confirm = confirm; 635 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 636 tab->nentries++; 637 success = 1; 638 } else { 639 key_free(k); 640 } 641 keys[i] = NULL; 642 } 643 send: 644 free(pin); 645 free(provider); 646 free(keys); 647 buffer_put_int(&e->output, 1); 648 buffer_put_char(&e->output, 649 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 650 } 651 652 static void 653 process_remove_smartcard_key(SocketEntry *e) 654 { 655 char *provider = NULL, *pin = NULL; 656 int version, success = 0; 657 Identity *id, *nxt; 658 Idtab *tab; 659 660 provider = buffer_get_string(&e->request, NULL); 661 pin = buffer_get_string(&e->request, NULL); 662 free(pin); 663 664 for (version = 1; version < 3; version++) { 665 tab = idtab_lookup(version); 666 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 667 nxt = TAILQ_NEXT(id, next); 668 /* Skip file--based keys */ 669 if (id->provider == NULL) 670 continue; 671 if (!strcmp(provider, id->provider)) { 672 TAILQ_REMOVE(&tab->idlist, id, next); 673 free_identity(id); 674 tab->nentries--; 675 } 676 } 677 } 678 if (pkcs11_del_provider(provider) == 0) 679 success = 1; 680 else 681 error("process_remove_smartcard_key:" 682 " pkcs11_del_provider failed"); 683 free(provider); 684 buffer_put_int(&e->output, 1); 685 buffer_put_char(&e->output, 686 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 687 } 688 #endif /* ENABLE_PKCS11 */ 689 690 /* dispatch incoming messages */ 691 692 static void 693 process_message(SocketEntry *e) 694 { 695 u_int msg_len, type; 696 u_char *cp; 697 698 if (buffer_len(&e->input) < 5) 699 return; /* Incomplete message. */ 700 cp = buffer_ptr(&e->input); 701 msg_len = get_u32(cp); 702 if (msg_len > 256 * 1024) { 703 close_socket(e); 704 return; 705 } 706 if (buffer_len(&e->input) < msg_len + 4) 707 return; 708 709 /* move the current input to e->request */ 710 buffer_consume(&e->input, 4); 711 buffer_clear(&e->request); 712 buffer_append(&e->request, buffer_ptr(&e->input), msg_len); 713 buffer_consume(&e->input, msg_len); 714 type = buffer_get_char(&e->request); 715 716 /* check wheter agent is locked */ 717 if (locked && type != SSH_AGENTC_UNLOCK) { 718 buffer_clear(&e->request); 719 switch (type) { 720 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 721 case SSH2_AGENTC_REQUEST_IDENTITIES: 722 /* send empty lists */ 723 no_identities(e, type); 724 break; 725 default: 726 /* send a fail message for all other request types */ 727 buffer_put_int(&e->output, 1); 728 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 729 } 730 return; 731 } 732 733 debug("type %d", type); 734 switch (type) { 735 case SSH_AGENTC_LOCK: 736 case SSH_AGENTC_UNLOCK: 737 process_lock_agent(e, type == SSH_AGENTC_LOCK); 738 break; 739 #ifdef WITH_SSH1 740 /* ssh1 */ 741 case SSH_AGENTC_RSA_CHALLENGE: 742 process_authentication_challenge1(e); 743 break; 744 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 745 process_request_identities(e, 1); 746 break; 747 case SSH_AGENTC_ADD_RSA_IDENTITY: 748 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 749 process_add_identity(e, 1); 750 break; 751 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 752 process_remove_identity(e, 1); 753 break; 754 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 755 process_remove_all_identities(e, 1); 756 break; 757 #endif 758 /* ssh2 */ 759 case SSH2_AGENTC_SIGN_REQUEST: 760 process_sign_request2(e); 761 break; 762 case SSH2_AGENTC_REQUEST_IDENTITIES: 763 process_request_identities(e, 2); 764 break; 765 case SSH2_AGENTC_ADD_IDENTITY: 766 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 767 process_add_identity(e, 2); 768 break; 769 case SSH2_AGENTC_REMOVE_IDENTITY: 770 process_remove_identity(e, 2); 771 break; 772 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 773 process_remove_all_identities(e, 2); 774 break; 775 #ifdef ENABLE_PKCS11 776 case SSH_AGENTC_ADD_SMARTCARD_KEY: 777 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 778 process_add_smartcard_key(e); 779 break; 780 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 781 process_remove_smartcard_key(e); 782 break; 783 #endif /* ENABLE_PKCS11 */ 784 default: 785 /* Unknown message. Respond with failure. */ 786 error("Unknown message %d", type); 787 buffer_clear(&e->request); 788 buffer_put_int(&e->output, 1); 789 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 790 break; 791 } 792 } 793 794 static void 795 new_socket(sock_type type, int fd) 796 { 797 u_int i, old_alloc, new_alloc; 798 799 set_nonblock(fd); 800 801 if (fd > max_fd) 802 max_fd = fd; 803 804 for (i = 0; i < sockets_alloc; i++) 805 if (sockets[i].type == AUTH_UNUSED) { 806 sockets[i].fd = fd; 807 buffer_init(&sockets[i].input); 808 buffer_init(&sockets[i].output); 809 buffer_init(&sockets[i].request); 810 sockets[i].type = type; 811 return; 812 } 813 old_alloc = sockets_alloc; 814 new_alloc = sockets_alloc + 10; 815 sockets = xrealloc(sockets, new_alloc, sizeof(sockets[0])); 816 for (i = old_alloc; i < new_alloc; i++) 817 sockets[i].type = AUTH_UNUSED; 818 sockets_alloc = new_alloc; 819 sockets[old_alloc].fd = fd; 820 buffer_init(&sockets[old_alloc].input); 821 buffer_init(&sockets[old_alloc].output); 822 buffer_init(&sockets[old_alloc].request); 823 sockets[old_alloc].type = type; 824 } 825 826 static int 827 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp, 828 struct timeval **tvpp) 829 { 830 u_int i, sz; 831 int n = 0; 832 static struct timeval tv; 833 time_t deadline; 834 835 for (i = 0; i < sockets_alloc; i++) { 836 switch (sockets[i].type) { 837 case AUTH_SOCKET: 838 case AUTH_CONNECTION: 839 n = MAX(n, sockets[i].fd); 840 break; 841 case AUTH_UNUSED: 842 break; 843 default: 844 fatal("Unknown socket type %d", sockets[i].type); 845 break; 846 } 847 } 848 849 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 850 if (*fdrp == NULL || sz > *nallocp) { 851 free(*fdrp); 852 free(*fdwp); 853 *fdrp = xmalloc(sz); 854 *fdwp = xmalloc(sz); 855 *nallocp = sz; 856 } 857 if (n < *fdl) 858 debug("XXX shrink: %d < %d", n, *fdl); 859 *fdl = n; 860 memset(*fdrp, 0, sz); 861 memset(*fdwp, 0, sz); 862 863 for (i = 0; i < sockets_alloc; i++) { 864 switch (sockets[i].type) { 865 case AUTH_SOCKET: 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); 870 break; 871 default: 872 break; 873 } 874 } 875 deadline = reaper(); 876 if (parent_alive_interval != 0) 877 deadline = (deadline == 0) ? parent_alive_interval : 878 MIN(deadline, parent_alive_interval); 879 if (deadline == 0) { 880 *tvpp = NULL; 881 } else { 882 tv.tv_sec = deadline; 883 tv.tv_usec = 0; 884 *tvpp = &tv; 885 } 886 return (1); 887 } 888 889 static void 890 after_select(fd_set *readset, fd_set *writeset) 891 { 892 struct sockaddr_un sunaddr; 893 socklen_t slen; 894 char buf[1024]; 895 int len, sock; 896 u_int i, orig_alloc; 897 uid_t euid; 898 gid_t egid; 899 900 for (i = 0, orig_alloc = sockets_alloc; i < orig_alloc; i++) 901 switch (sockets[i].type) { 902 case AUTH_UNUSED: 903 break; 904 case AUTH_SOCKET: 905 if (FD_ISSET(sockets[i].fd, readset)) { 906 slen = sizeof(sunaddr); 907 sock = accept(sockets[i].fd, 908 (struct sockaddr *)&sunaddr, &slen); 909 if (sock < 0) { 910 error("accept from AUTH_SOCKET: %s", 911 strerror(errno)); 912 break; 913 } 914 if (getpeereid(sock, &euid, &egid) < 0) { 915 error("getpeereid %d failed: %s", 916 sock, strerror(errno)); 917 close(sock); 918 break; 919 } 920 if ((euid != 0) && (getuid() != euid)) { 921 error("uid mismatch: " 922 "peer euid %u != uid %u", 923 (u_int) euid, (u_int) getuid()); 924 close(sock); 925 break; 926 } 927 new_socket(AUTH_CONNECTION, sock); 928 } 929 break; 930 case AUTH_CONNECTION: 931 if (buffer_len(&sockets[i].output) > 0 && 932 FD_ISSET(sockets[i].fd, writeset)) { 933 len = write(sockets[i].fd, 934 buffer_ptr(&sockets[i].output), 935 buffer_len(&sockets[i].output)); 936 if (len == -1 && (errno == EAGAIN || 937 errno == EINTR)) 938 continue; 939 if (len <= 0) { 940 close_socket(&sockets[i]); 941 break; 942 } 943 buffer_consume(&sockets[i].output, len); 944 } 945 if (FD_ISSET(sockets[i].fd, readset)) { 946 len = read(sockets[i].fd, buf, sizeof(buf)); 947 if (len == -1 && (errno == EAGAIN || 948 errno == EINTR)) 949 continue; 950 if (len <= 0) { 951 close_socket(&sockets[i]); 952 break; 953 } 954 buffer_append(&sockets[i].input, buf, len); 955 explicit_bzero(buf, sizeof(buf)); 956 process_message(&sockets[i]); 957 } 958 break; 959 default: 960 fatal("Unknown type %d", sockets[i].type); 961 } 962 } 963 964 static void 965 cleanup_socket(void) 966 { 967 if (cleanup_pid != 0 && getpid() != cleanup_pid) 968 return; 969 debug("%s: cleanup", __func__); 970 if (socket_name[0]) 971 unlink(socket_name); 972 if (socket_dir[0]) 973 rmdir(socket_dir); 974 } 975 976 void 977 cleanup_exit(int i) 978 { 979 cleanup_socket(); 980 _exit(i); 981 } 982 983 /*ARGSUSED*/ 984 static void 985 cleanup_handler(int sig) 986 { 987 cleanup_socket(); 988 #ifdef ENABLE_PKCS11 989 pkcs11_terminate(); 990 #endif 991 _exit(2); 992 } 993 994 static void 995 check_parent_exists(void) 996 { 997 /* 998 * If our parent has exited then getppid() will return (pid_t)1, 999 * so testing for that should be safe. 1000 */ 1001 if (parent_pid != -1 && getppid() != parent_pid) { 1002 /* printf("Parent has died - Authentication agent exiting.\n"); */ 1003 cleanup_socket(); 1004 _exit(2); 1005 } 1006 } 1007 1008 static void 1009 usage(void) 1010 { 1011 fprintf(stderr, 1012 "usage: ssh-agent [-c | -s] [-d] [-a bind_address] [-t life]\n" 1013 " [command [arg ...]]\n" 1014 " ssh-agent [-c | -s] -k\n"); 1015 exit(1); 1016 } 1017 1018 int 1019 main(int ac, char **av) 1020 { 1021 int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0; 1022 int sock, fd, ch, result, saved_errno; 1023 u_int nalloc; 1024 char *shell, *format, *pidstr, *agentsocket = NULL; 1025 fd_set *readsetp = NULL, *writesetp = NULL; 1026 struct rlimit rlim; 1027 extern int optind; 1028 extern char *optarg; 1029 pid_t pid; 1030 char pidstrbuf[1 + 3 * sizeof pid]; 1031 struct timeval *tvp = NULL; 1032 size_t len; 1033 mode_t prev_mask; 1034 1035 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1036 sanitise_stdfd(); 1037 1038 /* drop */ 1039 setegid(getgid()); 1040 setgid(getgid()); 1041 1042 #ifdef WITH_OPENSSL 1043 OpenSSL_add_all_algorithms(); 1044 #endif 1045 1046 while ((ch = getopt(ac, av, "cdksa:t:")) != -1) { 1047 switch (ch) { 1048 case 'c': 1049 if (s_flag) 1050 usage(); 1051 c_flag++; 1052 break; 1053 case 'k': 1054 k_flag++; 1055 break; 1056 case 's': 1057 if (c_flag) 1058 usage(); 1059 s_flag++; 1060 break; 1061 case 'd': 1062 if (d_flag) 1063 usage(); 1064 d_flag++; 1065 break; 1066 case 'a': 1067 agentsocket = optarg; 1068 break; 1069 case 't': 1070 if ((lifetime = convtime(optarg)) == -1) { 1071 fprintf(stderr, "Invalid lifetime\n"); 1072 usage(); 1073 } 1074 break; 1075 default: 1076 usage(); 1077 } 1078 } 1079 ac -= optind; 1080 av += optind; 1081 1082 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag)) 1083 usage(); 1084 1085 if (ac == 0 && !c_flag && !s_flag) { 1086 shell = getenv("SHELL"); 1087 if (shell != NULL && (len = strlen(shell)) > 2 && 1088 strncmp(shell + len - 3, "csh", 3) == 0) 1089 c_flag = 1; 1090 } 1091 if (k_flag) { 1092 const char *errstr = NULL; 1093 1094 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1095 if (pidstr == NULL) { 1096 fprintf(stderr, "%s not set, cannot kill agent\n", 1097 SSH_AGENTPID_ENV_NAME); 1098 exit(1); 1099 } 1100 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr); 1101 if (errstr) { 1102 fprintf(stderr, 1103 "%s=\"%s\", which is not a good PID: %s\n", 1104 SSH_AGENTPID_ENV_NAME, pidstr, errstr); 1105 exit(1); 1106 } 1107 if (kill(pid, SIGTERM) == -1) { 1108 perror("kill"); 1109 exit(1); 1110 } 1111 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 1112 printf(format, SSH_AUTHSOCKET_ENV_NAME); 1113 printf(format, SSH_AGENTPID_ENV_NAME); 1114 printf("echo Agent pid %ld killed;\n", (long)pid); 1115 exit(0); 1116 } 1117 parent_pid = getpid(); 1118 1119 if (agentsocket == NULL) { 1120 /* Create private directory for agent socket */ 1121 mktemp_proto(socket_dir, sizeof(socket_dir)); 1122 if (mkdtemp(socket_dir) == NULL) { 1123 perror("mkdtemp: private socket dir"); 1124 exit(1); 1125 } 1126 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1127 (long)parent_pid); 1128 } else { 1129 /* Try to use specified agent socket */ 1130 socket_dir[0] = '\0'; 1131 strlcpy(socket_name, agentsocket, sizeof socket_name); 1132 } 1133 1134 /* 1135 * Create socket early so it will exist before command gets run from 1136 * the parent. 1137 */ 1138 prev_mask = umask(0177); 1139 sock = unix_listener(socket_name, SSH_LISTEN_BACKLOG, 0); 1140 if (sock < 0) { 1141 /* XXX - unix_listener() calls error() not perror() */ 1142 *socket_name = '\0'; /* Don't unlink any existing file */ 1143 cleanup_exit(1); 1144 } 1145 umask(prev_mask); 1146 1147 /* 1148 * Fork, and have the parent execute the command, if any, or present 1149 * the socket data. The child continues as the authentication agent. 1150 */ 1151 if (d_flag) { 1152 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1); 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("echo Agent pid %ld;\n", (long)parent_pid); 1157 goto skip; 1158 } 1159 pid = fork(); 1160 if (pid == -1) { 1161 perror("fork"); 1162 cleanup_exit(1); 1163 } 1164 if (pid != 0) { /* Parent - execute the given command. */ 1165 close(sock); 1166 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1167 if (ac == 0) { 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(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 1172 SSH_AGENTPID_ENV_NAME); 1173 printf("echo Agent pid %ld;\n", (long)pid); 1174 exit(0); 1175 } 1176 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1177 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1178 perror("setenv"); 1179 exit(1); 1180 } 1181 execvp(av[0], av); 1182 perror(av[0]); 1183 exit(1); 1184 } 1185 /* child */ 1186 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1187 1188 if (setsid() == -1) { 1189 error("setsid: %s", strerror(errno)); 1190 cleanup_exit(1); 1191 } 1192 1193 (void)chdir("/"); 1194 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1195 /* XXX might close listen socket */ 1196 (void)dup2(fd, STDIN_FILENO); 1197 (void)dup2(fd, STDOUT_FILENO); 1198 (void)dup2(fd, STDERR_FILENO); 1199 if (fd > 2) 1200 close(fd); 1201 } 1202 1203 /* deny core dumps, since memory contains unencrypted private keys */ 1204 rlim.rlim_cur = rlim.rlim_max = 0; 1205 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 1206 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1207 cleanup_exit(1); 1208 } 1209 1210 skip: 1211 1212 cleanup_pid = getpid(); 1213 1214 #ifdef ENABLE_PKCS11 1215 pkcs11_init(0); 1216 #endif 1217 new_socket(AUTH_SOCKET, sock); 1218 if (ac > 0) 1219 parent_alive_interval = 10; 1220 idtab_init(); 1221 signal(SIGPIPE, SIG_IGN); 1222 signal(SIGINT, d_flag ? cleanup_handler : SIG_IGN); 1223 signal(SIGHUP, cleanup_handler); 1224 signal(SIGTERM, cleanup_handler); 1225 nalloc = 0; 1226 1227 while (1) { 1228 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp); 1229 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp); 1230 saved_errno = errno; 1231 if (parent_alive_interval != 0) 1232 check_parent_exists(); 1233 (void) reaper(); /* remove expired keys */ 1234 if (result < 0) { 1235 if (saved_errno == EINTR) 1236 continue; 1237 fatal("select: %s", strerror(saved_errno)); 1238 } else if (result > 0) 1239 after_select(readsetp, writesetp); 1240 } 1241 /* NOTREACHED */ 1242 } 1243