1 /* $OpenBSD: ssh-agent.c,v 1.166 2010/04/16 01:47:26 djm 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 #include <openssl/md5.h> 48 49 #include <errno.h> 50 #include <fcntl.h> 51 #include <paths.h> 52 #include <signal.h> 53 #include <stdlib.h> 54 #include <stdio.h> 55 #include <string.h> 56 #include <time.h> 57 #include <unistd.h> 58 59 #include "xmalloc.h" 60 #include "ssh.h" 61 #include "rsa.h" 62 #include "buffer.h" 63 #include "key.h" 64 #include "authfd.h" 65 #include "compat.h" 66 #include "log.h" 67 #include "misc.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 u_int 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 u_int 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 (0 == forever) */ 124 static int 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 if (id->provider != NULL) 162 xfree(id->provider); 163 xfree(id->comment); 164 xfree(id); 165 } 166 167 /* return matching private key for given public key */ 168 static Identity * 169 lookup_identity(Key *key, int version) 170 { 171 Identity *id; 172 173 Idtab *tab = idtab_lookup(version); 174 TAILQ_FOREACH(id, &tab->idlist, next) { 175 if (key_equal(key, id->key)) 176 return (id); 177 } 178 return (NULL); 179 } 180 181 /* Check confirmation of keysign request */ 182 static int 183 confirm_key(Identity *id) 184 { 185 char *p; 186 int ret = -1; 187 188 p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX); 189 if (ask_permission("Allow use of key %s?\nKey fingerprint %s.", 190 id->comment, p)) 191 ret = 0; 192 xfree(p); 193 194 return (ret); 195 } 196 197 /* send list of supported public keys to 'client' */ 198 static void 199 process_request_identities(SocketEntry *e, int version) 200 { 201 Idtab *tab = idtab_lookup(version); 202 Identity *id; 203 Buffer msg; 204 205 buffer_init(&msg); 206 buffer_put_char(&msg, (version == 1) ? 207 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 208 buffer_put_int(&msg, tab->nentries); 209 TAILQ_FOREACH(id, &tab->idlist, next) { 210 if (id->key->type == KEY_RSA1) { 211 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n)); 212 buffer_put_bignum(&msg, id->key->rsa->e); 213 buffer_put_bignum(&msg, id->key->rsa->n); 214 } else { 215 u_char *blob; 216 u_int blen; 217 key_to_blob(id->key, &blob, &blen); 218 buffer_put_string(&msg, blob, blen); 219 xfree(blob); 220 } 221 buffer_put_cstring(&msg, id->comment); 222 } 223 buffer_put_int(&e->output, buffer_len(&msg)); 224 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 225 buffer_free(&msg); 226 } 227 228 /* ssh1 only */ 229 static void 230 process_authentication_challenge1(SocketEntry *e) 231 { 232 u_char buf[32], mdbuf[16], session_id[16]; 233 u_int response_type; 234 BIGNUM *challenge; 235 Identity *id; 236 int i, len; 237 Buffer msg; 238 MD5_CTX md; 239 Key *key; 240 241 buffer_init(&msg); 242 key = key_new(KEY_RSA1); 243 if ((challenge = BN_new()) == NULL) 244 fatal("process_authentication_challenge1: BN_new failed"); 245 246 (void) buffer_get_int(&e->request); /* ignored */ 247 buffer_get_bignum(&e->request, key->rsa->e); 248 buffer_get_bignum(&e->request, key->rsa->n); 249 buffer_get_bignum(&e->request, challenge); 250 251 /* Only protocol 1.1 is supported */ 252 if (buffer_len(&e->request) == 0) 253 goto failure; 254 buffer_get(&e->request, session_id, 16); 255 response_type = buffer_get_int(&e->request); 256 if (response_type != 1) 257 goto failure; 258 259 id = lookup_identity(key, 1); 260 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) { 261 Key *private = id->key; 262 /* Decrypt the challenge using the private key. */ 263 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0) 264 goto failure; 265 266 /* The response is MD5 of decrypted challenge plus session id. */ 267 len = BN_num_bytes(challenge); 268 if (len <= 0 || len > 32) { 269 logit("process_authentication_challenge: bad challenge length %d", len); 270 goto failure; 271 } 272 memset(buf, 0, 32); 273 BN_bn2bin(challenge, buf + 32 - len); 274 MD5_Init(&md); 275 MD5_Update(&md, buf, 32); 276 MD5_Update(&md, session_id, 16); 277 MD5_Final(mdbuf, &md); 278 279 /* Send the response. */ 280 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE); 281 for (i = 0; i < 16; i++) 282 buffer_put_char(&msg, mdbuf[i]); 283 goto send; 284 } 285 286 failure: 287 /* Unknown identity or protocol error. Send failure. */ 288 buffer_put_char(&msg, SSH_AGENT_FAILURE); 289 send: 290 buffer_put_int(&e->output, buffer_len(&msg)); 291 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 292 key_free(key); 293 BN_clear_free(challenge); 294 buffer_free(&msg); 295 } 296 297 /* ssh2 only */ 298 static void 299 process_sign_request2(SocketEntry *e) 300 { 301 u_char *blob, *data, *signature = NULL; 302 u_int blen, dlen, slen = 0; 303 extern int datafellows; 304 int odatafellows; 305 int ok = -1, flags; 306 Buffer msg; 307 Key *key; 308 309 datafellows = 0; 310 311 blob = buffer_get_string(&e->request, &blen); 312 data = buffer_get_string(&e->request, &dlen); 313 314 flags = buffer_get_int(&e->request); 315 odatafellows = datafellows; 316 if (flags & SSH_AGENT_OLD_SIGNATURE) 317 datafellows = SSH_BUG_SIGBLOB; 318 319 key = key_from_blob(blob, blen); 320 if (key != NULL) { 321 Identity *id = lookup_identity(key, 2); 322 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) 323 ok = key_sign(id->key, &signature, &slen, data, dlen); 324 key_free(key); 325 } 326 buffer_init(&msg); 327 if (ok == 0) { 328 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); 329 buffer_put_string(&msg, signature, slen); 330 } else { 331 buffer_put_char(&msg, SSH_AGENT_FAILURE); 332 } 333 buffer_put_int(&e->output, buffer_len(&msg)); 334 buffer_append(&e->output, buffer_ptr(&msg), 335 buffer_len(&msg)); 336 buffer_free(&msg); 337 xfree(data); 338 xfree(blob); 339 if (signature != NULL) 340 xfree(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 xfree(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 u_int 420 reaper(void) 421 { 422 u_int deadline = 0, now = time(NULL); 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, death = 0, confirm = 0; 455 char *type_name, *comment; 456 Key *k = NULL; 457 u_char *cert; 458 u_int len; 459 460 switch (version) { 461 case 1: 462 k = key_new_private(KEY_RSA1); 463 (void) buffer_get_int(&e->request); /* ignored */ 464 buffer_get_bignum(&e->request, k->rsa->n); 465 buffer_get_bignum(&e->request, k->rsa->e); 466 buffer_get_bignum(&e->request, k->rsa->d); 467 buffer_get_bignum(&e->request, k->rsa->iqmp); 468 469 /* SSH and SSL have p and q swapped */ 470 buffer_get_bignum(&e->request, k->rsa->q); /* p */ 471 buffer_get_bignum(&e->request, k->rsa->p); /* q */ 472 473 /* Generate additional parameters */ 474 rsa_generate_additional_parameters(k->rsa); 475 break; 476 case 2: 477 type_name = buffer_get_string(&e->request, NULL); 478 type = key_type_from_name(type_name); 479 xfree(type_name); 480 switch (type) { 481 case KEY_DSA: 482 k = key_new_private(type); 483 buffer_get_bignum2(&e->request, k->dsa->p); 484 buffer_get_bignum2(&e->request, k->dsa->q); 485 buffer_get_bignum2(&e->request, k->dsa->g); 486 buffer_get_bignum2(&e->request, k->dsa->pub_key); 487 buffer_get_bignum2(&e->request, k->dsa->priv_key); 488 break; 489 case KEY_DSA_CERT_V00: 490 case KEY_DSA_CERT: 491 cert = buffer_get_string(&e->request, &len); 492 if ((k = key_from_blob(cert, len)) == NULL) 493 fatal("Certificate parse failed"); 494 xfree(cert); 495 key_add_private(k); 496 buffer_get_bignum2(&e->request, k->dsa->priv_key); 497 break; 498 case KEY_RSA: 499 k = key_new_private(type); 500 buffer_get_bignum2(&e->request, k->rsa->n); 501 buffer_get_bignum2(&e->request, k->rsa->e); 502 buffer_get_bignum2(&e->request, k->rsa->d); 503 buffer_get_bignum2(&e->request, k->rsa->iqmp); 504 buffer_get_bignum2(&e->request, k->rsa->p); 505 buffer_get_bignum2(&e->request, k->rsa->q); 506 507 /* Generate additional parameters */ 508 rsa_generate_additional_parameters(k->rsa); 509 break; 510 case KEY_RSA_CERT_V00: 511 case KEY_RSA_CERT: 512 cert = buffer_get_string(&e->request, &len); 513 if ((k = key_from_blob(cert, len)) == NULL) 514 fatal("Certificate parse failed"); 515 xfree(cert); 516 key_add_private(k); 517 buffer_get_bignum2(&e->request, k->rsa->d); 518 buffer_get_bignum2(&e->request, k->rsa->iqmp); 519 buffer_get_bignum2(&e->request, k->rsa->p); 520 buffer_get_bignum2(&e->request, k->rsa->q); 521 break; 522 default: 523 buffer_clear(&e->request); 524 goto send; 525 } 526 break; 527 } 528 /* enable blinding */ 529 switch (k->type) { 530 case KEY_RSA: 531 case KEY_RSA_CERT_V00: 532 case KEY_RSA_CERT: 533 case KEY_RSA1: 534 if (RSA_blinding_on(k->rsa, NULL) != 1) { 535 error("process_add_identity: RSA_blinding_on failed"); 536 key_free(k); 537 goto send; 538 } 539 break; 540 } 541 comment = buffer_get_string(&e->request, NULL); 542 if (k == NULL) { 543 xfree(comment); 544 goto send; 545 } 546 while (buffer_len(&e->request)) { 547 switch ((type = buffer_get_char(&e->request))) { 548 case SSH_AGENT_CONSTRAIN_LIFETIME: 549 death = time(NULL) + buffer_get_int(&e->request); 550 break; 551 case SSH_AGENT_CONSTRAIN_CONFIRM: 552 confirm = 1; 553 break; 554 default: 555 error("process_add_identity: " 556 "Unknown constraint type %d", type); 557 xfree(comment); 558 key_free(k); 559 goto send; 560 } 561 } 562 success = 1; 563 if (lifetime && !death) 564 death = time(NULL) + lifetime; 565 if ((id = lookup_identity(k, version)) == NULL) { 566 id = xcalloc(1, sizeof(Identity)); 567 id->key = k; 568 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 569 /* Increment the number of identities. */ 570 tab->nentries++; 571 } else { 572 key_free(k); 573 xfree(id->comment); 574 } 575 id->comment = comment; 576 id->death = death; 577 id->confirm = confirm; 578 send: 579 buffer_put_int(&e->output, 1); 580 buffer_put_char(&e->output, 581 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 582 } 583 584 /* XXX todo: encrypt sensitive data with passphrase */ 585 static void 586 process_lock_agent(SocketEntry *e, int lock) 587 { 588 int success = 0; 589 char *passwd; 590 591 passwd = buffer_get_string(&e->request, NULL); 592 if (locked && !lock && strcmp(passwd, lock_passwd) == 0) { 593 locked = 0; 594 memset(lock_passwd, 0, strlen(lock_passwd)); 595 xfree(lock_passwd); 596 lock_passwd = NULL; 597 success = 1; 598 } else if (!locked && lock) { 599 locked = 1; 600 lock_passwd = xstrdup(passwd); 601 success = 1; 602 } 603 memset(passwd, 0, strlen(passwd)); 604 xfree(passwd); 605 606 buffer_put_int(&e->output, 1); 607 buffer_put_char(&e->output, 608 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 609 } 610 611 static void 612 no_identities(SocketEntry *e, u_int type) 613 { 614 Buffer msg; 615 616 buffer_init(&msg); 617 buffer_put_char(&msg, 618 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ? 619 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 620 buffer_put_int(&msg, 0); 621 buffer_put_int(&e->output, buffer_len(&msg)); 622 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 623 buffer_free(&msg); 624 } 625 626 #ifdef ENABLE_PKCS11 627 static void 628 process_add_smartcard_key(SocketEntry *e) 629 { 630 char *provider = NULL, *pin; 631 int i, type, version, count = 0, success = 0, death = 0, confirm = 0; 632 Key **keys = NULL, *k; 633 Identity *id; 634 Idtab *tab; 635 636 provider = buffer_get_string(&e->request, NULL); 637 pin = buffer_get_string(&e->request, NULL); 638 639 while (buffer_len(&e->request)) { 640 switch ((type = buffer_get_char(&e->request))) { 641 case SSH_AGENT_CONSTRAIN_LIFETIME: 642 death = time(NULL) + buffer_get_int(&e->request); 643 break; 644 case SSH_AGENT_CONSTRAIN_CONFIRM: 645 confirm = 1; 646 break; 647 default: 648 error("process_add_smartcard_key: " 649 "Unknown constraint type %d", type); 650 goto send; 651 } 652 } 653 if (lifetime && !death) 654 death = time(NULL) + lifetime; 655 656 count = pkcs11_add_provider(provider, pin, &keys); 657 for (i = 0; i < count; i++) { 658 k = keys[i]; 659 version = k->type == KEY_RSA1 ? 1 : 2; 660 tab = idtab_lookup(version); 661 if (lookup_identity(k, version) == NULL) { 662 id = xcalloc(1, sizeof(Identity)); 663 id->key = k; 664 id->provider = xstrdup(provider); 665 id->comment = xstrdup(provider); /* XXX */ 666 id->death = death; 667 id->confirm = confirm; 668 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 669 tab->nentries++; 670 success = 1; 671 } else { 672 key_free(k); 673 } 674 keys[i] = NULL; 675 } 676 send: 677 if (pin) 678 xfree(pin); 679 if (provider) 680 xfree(provider); 681 if (keys) 682 xfree(keys); 683 buffer_put_int(&e->output, 1); 684 buffer_put_char(&e->output, 685 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 686 } 687 688 static void 689 process_remove_smartcard_key(SocketEntry *e) 690 { 691 char *provider = NULL, *pin = NULL; 692 int version, success = 0; 693 Identity *id, *nxt; 694 Idtab *tab; 695 696 provider = buffer_get_string(&e->request, NULL); 697 pin = buffer_get_string(&e->request, NULL); 698 xfree(pin); 699 700 for (version = 1; version < 3; version++) { 701 tab = idtab_lookup(version); 702 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 703 nxt = TAILQ_NEXT(id, next); 704 if (!strcmp(provider, id->provider)) { 705 TAILQ_REMOVE(&tab->idlist, id, next); 706 free_identity(id); 707 tab->nentries--; 708 } 709 } 710 } 711 if (pkcs11_del_provider(provider) == 0) 712 success = 1; 713 else 714 error("process_remove_smartcard_key:" 715 " pkcs11_del_provider failed"); 716 xfree(provider); 717 buffer_put_int(&e->output, 1); 718 buffer_put_char(&e->output, 719 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 720 } 721 #endif /* ENABLE_PKCS11 */ 722 723 /* dispatch incoming messages */ 724 725 static void 726 process_message(SocketEntry *e) 727 { 728 u_int msg_len, type; 729 u_char *cp; 730 731 if (buffer_len(&e->input) < 5) 732 return; /* Incomplete message. */ 733 cp = buffer_ptr(&e->input); 734 msg_len = get_u32(cp); 735 if (msg_len > 256 * 1024) { 736 close_socket(e); 737 return; 738 } 739 if (buffer_len(&e->input) < msg_len + 4) 740 return; 741 742 /* move the current input to e->request */ 743 buffer_consume(&e->input, 4); 744 buffer_clear(&e->request); 745 buffer_append(&e->request, buffer_ptr(&e->input), msg_len); 746 buffer_consume(&e->input, msg_len); 747 type = buffer_get_char(&e->request); 748 749 /* check wheter agent is locked */ 750 if (locked && type != SSH_AGENTC_UNLOCK) { 751 buffer_clear(&e->request); 752 switch (type) { 753 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 754 case SSH2_AGENTC_REQUEST_IDENTITIES: 755 /* send empty lists */ 756 no_identities(e, type); 757 break; 758 default: 759 /* send a fail message for all other request types */ 760 buffer_put_int(&e->output, 1); 761 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 762 } 763 return; 764 } 765 766 debug("type %d", type); 767 switch (type) { 768 case SSH_AGENTC_LOCK: 769 case SSH_AGENTC_UNLOCK: 770 process_lock_agent(e, type == SSH_AGENTC_LOCK); 771 break; 772 /* ssh1 */ 773 case SSH_AGENTC_RSA_CHALLENGE: 774 process_authentication_challenge1(e); 775 break; 776 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 777 process_request_identities(e, 1); 778 break; 779 case SSH_AGENTC_ADD_RSA_IDENTITY: 780 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 781 process_add_identity(e, 1); 782 break; 783 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 784 process_remove_identity(e, 1); 785 break; 786 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 787 process_remove_all_identities(e, 1); 788 break; 789 /* ssh2 */ 790 case SSH2_AGENTC_SIGN_REQUEST: 791 process_sign_request2(e); 792 break; 793 case SSH2_AGENTC_REQUEST_IDENTITIES: 794 process_request_identities(e, 2); 795 break; 796 case SSH2_AGENTC_ADD_IDENTITY: 797 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 798 process_add_identity(e, 2); 799 break; 800 case SSH2_AGENTC_REMOVE_IDENTITY: 801 process_remove_identity(e, 2); 802 break; 803 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 804 process_remove_all_identities(e, 2); 805 break; 806 #ifdef ENABLE_PKCS11 807 case SSH_AGENTC_ADD_SMARTCARD_KEY: 808 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 809 process_add_smartcard_key(e); 810 break; 811 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 812 process_remove_smartcard_key(e); 813 break; 814 #endif /* ENABLE_PKCS11 */ 815 default: 816 /* Unknown message. Respond with failure. */ 817 error("Unknown message %d", type); 818 buffer_clear(&e->request); 819 buffer_put_int(&e->output, 1); 820 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 821 break; 822 } 823 } 824 825 static void 826 new_socket(sock_type type, int fd) 827 { 828 u_int i, old_alloc, new_alloc; 829 830 set_nonblock(fd); 831 832 if (fd > max_fd) 833 max_fd = fd; 834 835 for (i = 0; i < sockets_alloc; i++) 836 if (sockets[i].type == AUTH_UNUSED) { 837 sockets[i].fd = fd; 838 buffer_init(&sockets[i].input); 839 buffer_init(&sockets[i].output); 840 buffer_init(&sockets[i].request); 841 sockets[i].type = type; 842 return; 843 } 844 old_alloc = sockets_alloc; 845 new_alloc = sockets_alloc + 10; 846 sockets = xrealloc(sockets, new_alloc, sizeof(sockets[0])); 847 for (i = old_alloc; i < new_alloc; i++) 848 sockets[i].type = AUTH_UNUSED; 849 sockets_alloc = new_alloc; 850 sockets[old_alloc].fd = fd; 851 buffer_init(&sockets[old_alloc].input); 852 buffer_init(&sockets[old_alloc].output); 853 buffer_init(&sockets[old_alloc].request); 854 sockets[old_alloc].type = type; 855 } 856 857 static int 858 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp, 859 struct timeval **tvpp) 860 { 861 u_int i, sz, deadline; 862 int n = 0; 863 static struct timeval tv; 864 865 for (i = 0; i < sockets_alloc; i++) { 866 switch (sockets[i].type) { 867 case AUTH_SOCKET: 868 case AUTH_CONNECTION: 869 n = MAX(n, sockets[i].fd); 870 break; 871 case AUTH_UNUSED: 872 break; 873 default: 874 fatal("Unknown socket type %d", sockets[i].type); 875 break; 876 } 877 } 878 879 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 880 if (*fdrp == NULL || sz > *nallocp) { 881 if (*fdrp) 882 xfree(*fdrp); 883 if (*fdwp) 884 xfree(*fdwp); 885 *fdrp = xmalloc(sz); 886 *fdwp = xmalloc(sz); 887 *nallocp = sz; 888 } 889 if (n < *fdl) 890 debug("XXX shrink: %d < %d", n, *fdl); 891 *fdl = n; 892 memset(*fdrp, 0, sz); 893 memset(*fdwp, 0, sz); 894 895 for (i = 0; i < sockets_alloc; i++) { 896 switch (sockets[i].type) { 897 case AUTH_SOCKET: 898 case AUTH_CONNECTION: 899 FD_SET(sockets[i].fd, *fdrp); 900 if (buffer_len(&sockets[i].output) > 0) 901 FD_SET(sockets[i].fd, *fdwp); 902 break; 903 default: 904 break; 905 } 906 } 907 deadline = reaper(); 908 if (parent_alive_interval != 0) 909 deadline = (deadline == 0) ? parent_alive_interval : 910 MIN(deadline, parent_alive_interval); 911 if (deadline == 0) { 912 *tvpp = NULL; 913 } else { 914 tv.tv_sec = deadline; 915 tv.tv_usec = 0; 916 *tvpp = &tv; 917 } 918 return (1); 919 } 920 921 static void 922 after_select(fd_set *readset, fd_set *writeset) 923 { 924 struct sockaddr_un sunaddr; 925 socklen_t slen; 926 char buf[1024]; 927 int len, sock; 928 u_int i, orig_alloc; 929 uid_t euid; 930 gid_t egid; 931 932 for (i = 0, orig_alloc = sockets_alloc; i < orig_alloc; i++) 933 switch (sockets[i].type) { 934 case AUTH_UNUSED: 935 break; 936 case AUTH_SOCKET: 937 if (FD_ISSET(sockets[i].fd, readset)) { 938 slen = sizeof(sunaddr); 939 sock = accept(sockets[i].fd, 940 (struct sockaddr *)&sunaddr, &slen); 941 if (sock < 0) { 942 error("accept from AUTH_SOCKET: %s", 943 strerror(errno)); 944 break; 945 } 946 if (getpeereid(sock, &euid, &egid) < 0) { 947 error("getpeereid %d failed: %s", 948 sock, strerror(errno)); 949 close(sock); 950 break; 951 } 952 if ((euid != 0) && (getuid() != euid)) { 953 error("uid mismatch: " 954 "peer euid %u != uid %u", 955 (u_int) euid, (u_int) getuid()); 956 close(sock); 957 break; 958 } 959 new_socket(AUTH_CONNECTION, sock); 960 } 961 break; 962 case AUTH_CONNECTION: 963 if (buffer_len(&sockets[i].output) > 0 && 964 FD_ISSET(sockets[i].fd, writeset)) { 965 len = write(sockets[i].fd, 966 buffer_ptr(&sockets[i].output), 967 buffer_len(&sockets[i].output)); 968 if (len == -1 && (errno == EAGAIN || 969 errno == EINTR)) 970 continue; 971 if (len <= 0) { 972 close_socket(&sockets[i]); 973 break; 974 } 975 buffer_consume(&sockets[i].output, len); 976 } 977 if (FD_ISSET(sockets[i].fd, readset)) { 978 len = read(sockets[i].fd, buf, sizeof(buf)); 979 if (len == -1 && (errno == EAGAIN || 980 errno == EINTR)) 981 continue; 982 if (len <= 0) { 983 close_socket(&sockets[i]); 984 break; 985 } 986 buffer_append(&sockets[i].input, buf, len); 987 process_message(&sockets[i]); 988 } 989 break; 990 default: 991 fatal("Unknown type %d", sockets[i].type); 992 } 993 } 994 995 static void 996 cleanup_socket(void) 997 { 998 if (socket_name[0]) 999 unlink(socket_name); 1000 if (socket_dir[0]) 1001 rmdir(socket_dir); 1002 } 1003 1004 void 1005 cleanup_exit(int i) 1006 { 1007 cleanup_socket(); 1008 _exit(i); 1009 } 1010 1011 /*ARGSUSED*/ 1012 static void 1013 cleanup_handler(int sig) 1014 { 1015 cleanup_socket(); 1016 #ifdef ENABLE_PKCS11 1017 pkcs11_terminate(); 1018 #endif 1019 _exit(2); 1020 } 1021 1022 static void 1023 check_parent_exists(void) 1024 { 1025 if (parent_pid != -1 && kill(parent_pid, 0) < 0) { 1026 /* printf("Parent has died - Authentication agent exiting.\n"); */ 1027 cleanup_socket(); 1028 _exit(2); 1029 } 1030 } 1031 1032 static void 1033 usage(void) 1034 { 1035 fprintf(stderr, "usage: %s [options] [command [arg ...]]\n", 1036 __progname); 1037 fprintf(stderr, "Options:\n"); 1038 fprintf(stderr, " -c Generate C-shell commands on stdout.\n"); 1039 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n"); 1040 fprintf(stderr, " -k Kill the current agent.\n"); 1041 fprintf(stderr, " -d Debug mode.\n"); 1042 fprintf(stderr, " -a socket Bind agent socket to given name.\n"); 1043 fprintf(stderr, " -t life Default identity lifetime (seconds).\n"); 1044 exit(1); 1045 } 1046 1047 int 1048 main(int ac, char **av) 1049 { 1050 int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0; 1051 int sock, fd, ch, result, saved_errno; 1052 u_int nalloc; 1053 char *shell, *format, *pidstr, *agentsocket = NULL; 1054 fd_set *readsetp = NULL, *writesetp = NULL; 1055 struct sockaddr_un sunaddr; 1056 struct rlimit rlim; 1057 extern int optind; 1058 extern char *optarg; 1059 pid_t pid; 1060 char pidstrbuf[1 + 3 * sizeof pid]; 1061 struct timeval *tvp = NULL; 1062 size_t len; 1063 1064 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1065 sanitise_stdfd(); 1066 1067 /* drop */ 1068 setegid(getgid()); 1069 setgid(getgid()); 1070 1071 SSLeay_add_all_algorithms(); 1072 1073 while ((ch = getopt(ac, av, "cdksa:t:")) != -1) { 1074 switch (ch) { 1075 case 'c': 1076 if (s_flag) 1077 usage(); 1078 c_flag++; 1079 break; 1080 case 'k': 1081 k_flag++; 1082 break; 1083 case 's': 1084 if (c_flag) 1085 usage(); 1086 s_flag++; 1087 break; 1088 case 'd': 1089 if (d_flag) 1090 usage(); 1091 d_flag++; 1092 break; 1093 case 'a': 1094 agentsocket = optarg; 1095 break; 1096 case 't': 1097 if ((lifetime = convtime(optarg)) == -1) { 1098 fprintf(stderr, "Invalid lifetime\n"); 1099 usage(); 1100 } 1101 break; 1102 default: 1103 usage(); 1104 } 1105 } 1106 ac -= optind; 1107 av += optind; 1108 1109 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag)) 1110 usage(); 1111 1112 if (ac == 0 && !c_flag && !s_flag) { 1113 shell = getenv("SHELL"); 1114 if (shell != NULL && (len = strlen(shell)) > 2 && 1115 strncmp(shell + len - 3, "csh", 3) == 0) 1116 c_flag = 1; 1117 } 1118 if (k_flag) { 1119 const char *errstr = NULL; 1120 1121 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1122 if (pidstr == NULL) { 1123 fprintf(stderr, "%s not set, cannot kill agent\n", 1124 SSH_AGENTPID_ENV_NAME); 1125 exit(1); 1126 } 1127 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr); 1128 if (errstr) { 1129 fprintf(stderr, 1130 "%s=\"%s\", which is not a good PID: %s\n", 1131 SSH_AGENTPID_ENV_NAME, pidstr, errstr); 1132 exit(1); 1133 } 1134 if (kill(pid, SIGTERM) == -1) { 1135 perror("kill"); 1136 exit(1); 1137 } 1138 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 1139 printf(format, SSH_AUTHSOCKET_ENV_NAME); 1140 printf(format, SSH_AGENTPID_ENV_NAME); 1141 printf("echo Agent pid %ld killed;\n", (long)pid); 1142 exit(0); 1143 } 1144 parent_pid = getpid(); 1145 1146 if (agentsocket == NULL) { 1147 /* Create private directory for agent socket */ 1148 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXXXX", sizeof socket_dir); 1149 if (mkdtemp(socket_dir) == NULL) { 1150 perror("mkdtemp: private socket dir"); 1151 exit(1); 1152 } 1153 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1154 (long)parent_pid); 1155 } else { 1156 /* Try to use specified agent socket */ 1157 socket_dir[0] = '\0'; 1158 strlcpy(socket_name, agentsocket, sizeof socket_name); 1159 } 1160 1161 /* 1162 * Create socket early so it will exist before command gets run from 1163 * the parent. 1164 */ 1165 sock = socket(AF_UNIX, SOCK_STREAM, 0); 1166 if (sock < 0) { 1167 perror("socket"); 1168 *socket_name = '\0'; /* Don't unlink any existing file */ 1169 cleanup_exit(1); 1170 } 1171 memset(&sunaddr, 0, sizeof(sunaddr)); 1172 sunaddr.sun_family = AF_UNIX; 1173 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); 1174 if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) { 1175 perror("bind"); 1176 *socket_name = '\0'; /* Don't unlink any existing file */ 1177 cleanup_exit(1); 1178 } 1179 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 1180 perror("listen"); 1181 cleanup_exit(1); 1182 } 1183 1184 /* 1185 * Fork, and have the parent execute the command, if any, or present 1186 * the socket data. The child continues as the authentication agent. 1187 */ 1188 if (d_flag) { 1189 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1); 1190 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1191 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1192 SSH_AUTHSOCKET_ENV_NAME); 1193 printf("echo Agent pid %ld;\n", (long)parent_pid); 1194 goto skip; 1195 } 1196 pid = fork(); 1197 if (pid == -1) { 1198 perror("fork"); 1199 cleanup_exit(1); 1200 } 1201 if (pid != 0) { /* Parent - execute the given command. */ 1202 close(sock); 1203 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1204 if (ac == 0) { 1205 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1206 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1207 SSH_AUTHSOCKET_ENV_NAME); 1208 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 1209 SSH_AGENTPID_ENV_NAME); 1210 printf("echo Agent pid %ld;\n", (long)pid); 1211 exit(0); 1212 } 1213 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1214 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1215 perror("setenv"); 1216 exit(1); 1217 } 1218 execvp(av[0], av); 1219 perror(av[0]); 1220 exit(1); 1221 } 1222 /* child */ 1223 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1224 1225 if (setsid() == -1) { 1226 error("setsid: %s", strerror(errno)); 1227 cleanup_exit(1); 1228 } 1229 1230 (void)chdir("/"); 1231 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1232 /* XXX might close listen socket */ 1233 (void)dup2(fd, STDIN_FILENO); 1234 (void)dup2(fd, STDOUT_FILENO); 1235 (void)dup2(fd, STDERR_FILENO); 1236 if (fd > 2) 1237 close(fd); 1238 } 1239 1240 /* deny core dumps, since memory contains unencrypted private keys */ 1241 rlim.rlim_cur = rlim.rlim_max = 0; 1242 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 1243 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1244 cleanup_exit(1); 1245 } 1246 1247 skip: 1248 1249 #ifdef ENABLE_PKCS11 1250 pkcs11_init(0); 1251 #endif 1252 new_socket(AUTH_SOCKET, sock); 1253 if (ac > 0) 1254 parent_alive_interval = 10; 1255 idtab_init(); 1256 if (!d_flag) 1257 signal(SIGINT, SIG_IGN); 1258 signal(SIGPIPE, SIG_IGN); 1259 signal(SIGHUP, cleanup_handler); 1260 signal(SIGTERM, cleanup_handler); 1261 nalloc = 0; 1262 1263 while (1) { 1264 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp); 1265 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp); 1266 saved_errno = errno; 1267 if (parent_alive_interval != 0) 1268 check_parent_exists(); 1269 (void) reaper(); /* remove expired keys */ 1270 if (result < 0) { 1271 if (saved_errno == EINTR) 1272 continue; 1273 fatal("select: %s", strerror(saved_errno)); 1274 } else if (result > 0) 1275 after_select(readsetp, writesetp); 1276 } 1277 /* NOTREACHED */ 1278 } 1279