1 /* 2 * Author: Tatu Ylonen <ylo@cs.hut.fi> 3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 4 * All rights reserved 5 * The authentication agent program. 6 * 7 * As far as I am concerned, the code I have written for this software 8 * can be used freely for any purpose. Any derived versions of this 9 * software must be clearly marked as such, and if the derived work is 10 * incompatible with the protocol description in the RFC file, it must be 11 * called by a name other than "ssh" or "Secure Shell". 12 * 13 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 14 * 15 * Redistribution and use in source and binary forms, with or without 16 * modification, are permitted provided that the following conditions 17 * are met: 18 * 1. Redistributions of source code must retain the above copyright 19 * notice, this list of conditions and the following disclaimer. 20 * 2. Redistributions in binary form must reproduce the above copyright 21 * notice, this list of conditions and the following disclaimer in the 22 * documentation and/or other materials provided with the distribution. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 27 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 29 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34 */ 35 36 #include "includes.h" 37 #include <sys/queue.h> 38 RCSID("$OpenBSD: ssh-agent.c,v 1.122 2004/10/29 22:53:56 djm Exp $"); 39 40 #include <openssl/evp.h> 41 #include <openssl/md5.h> 42 43 #include "ssh.h" 44 #include "rsa.h" 45 #include "buffer.h" 46 #include "bufaux.h" 47 #include "xmalloc.h" 48 #include "getput.h" 49 #include "key.h" 50 #include "authfd.h" 51 #include "compat.h" 52 #include "log.h" 53 #include "misc.h" 54 55 #ifdef SMARTCARD 56 #include "scard.h" 57 #endif 58 59 typedef enum { 60 AUTH_UNUSED, 61 AUTH_SOCKET, 62 AUTH_CONNECTION 63 } sock_type; 64 65 typedef struct { 66 int fd; 67 sock_type type; 68 Buffer input; 69 Buffer output; 70 Buffer request; 71 } SocketEntry; 72 73 u_int sockets_alloc = 0; 74 SocketEntry *sockets = NULL; 75 76 typedef struct identity { 77 TAILQ_ENTRY(identity) next; 78 Key *key; 79 char *comment; 80 u_int death; 81 u_int confirm; 82 } Identity; 83 84 typedef struct { 85 int nentries; 86 TAILQ_HEAD(idqueue, identity) idlist; 87 } Idtab; 88 89 /* private key table, one per protocol version */ 90 Idtab idtable[3]; 91 92 int max_fd = 0; 93 94 /* pid of shell == parent of agent */ 95 pid_t parent_pid = -1; 96 97 /* pathname and directory for AUTH_SOCKET */ 98 char socket_name[1024]; 99 char socket_dir[1024]; 100 101 /* locking */ 102 int locked = 0; 103 char *lock_passwd = NULL; 104 105 extern char *__progname; 106 107 /* Default lifetime (0 == forever) */ 108 static int lifetime = 0; 109 110 static void 111 close_socket(SocketEntry *e) 112 { 113 close(e->fd); 114 e->fd = -1; 115 e->type = AUTH_UNUSED; 116 buffer_free(&e->input); 117 buffer_free(&e->output); 118 buffer_free(&e->request); 119 } 120 121 static void 122 idtab_init(void) 123 { 124 int i; 125 126 for (i = 0; i <=2; i++) { 127 TAILQ_INIT(&idtable[i].idlist); 128 idtable[i].nentries = 0; 129 } 130 } 131 132 /* return private key table for requested protocol version */ 133 static Idtab * 134 idtab_lookup(int version) 135 { 136 if (version < 1 || version > 2) 137 fatal("internal error, bad protocol version %d", version); 138 return &idtable[version]; 139 } 140 141 static void 142 free_identity(Identity *id) 143 { 144 key_free(id->key); 145 xfree(id->comment); 146 xfree(id); 147 } 148 149 /* return matching private key for given public key */ 150 static Identity * 151 lookup_identity(Key *key, int version) 152 { 153 Identity *id; 154 155 Idtab *tab = idtab_lookup(version); 156 TAILQ_FOREACH(id, &tab->idlist, next) { 157 if (key_equal(key, id->key)) 158 return (id); 159 } 160 return (NULL); 161 } 162 163 /* Check confirmation of keysign request */ 164 static int 165 confirm_key(Identity *id) 166 { 167 char *p; 168 int ret = -1; 169 170 p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX); 171 if (ask_permission("Allow use of key %s?\nKey fingerprint %s.", 172 id->comment, p)) 173 ret = 0; 174 xfree(p); 175 176 return (ret); 177 } 178 179 /* send list of supported public keys to 'client' */ 180 static void 181 process_request_identities(SocketEntry *e, int version) 182 { 183 Idtab *tab = idtab_lookup(version); 184 Identity *id; 185 Buffer msg; 186 187 buffer_init(&msg); 188 buffer_put_char(&msg, (version == 1) ? 189 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 190 buffer_put_int(&msg, tab->nentries); 191 TAILQ_FOREACH(id, &tab->idlist, next) { 192 if (id->key->type == KEY_RSA1) { 193 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n)); 194 buffer_put_bignum(&msg, id->key->rsa->e); 195 buffer_put_bignum(&msg, id->key->rsa->n); 196 } else { 197 u_char *blob; 198 u_int blen; 199 key_to_blob(id->key, &blob, &blen); 200 buffer_put_string(&msg, blob, blen); 201 xfree(blob); 202 } 203 buffer_put_cstring(&msg, id->comment); 204 } 205 buffer_put_int(&e->output, buffer_len(&msg)); 206 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 207 buffer_free(&msg); 208 } 209 210 /* ssh1 only */ 211 static void 212 process_authentication_challenge1(SocketEntry *e) 213 { 214 u_char buf[32], mdbuf[16], session_id[16]; 215 u_int response_type; 216 BIGNUM *challenge; 217 Identity *id; 218 int i, len; 219 Buffer msg; 220 MD5_CTX md; 221 Key *key; 222 223 buffer_init(&msg); 224 key = key_new(KEY_RSA1); 225 if ((challenge = BN_new()) == NULL) 226 fatal("process_authentication_challenge1: BN_new failed"); 227 228 (void) buffer_get_int(&e->request); /* ignored */ 229 buffer_get_bignum(&e->request, key->rsa->e); 230 buffer_get_bignum(&e->request, key->rsa->n); 231 buffer_get_bignum(&e->request, challenge); 232 233 /* Only protocol 1.1 is supported */ 234 if (buffer_len(&e->request) == 0) 235 goto failure; 236 buffer_get(&e->request, session_id, 16); 237 response_type = buffer_get_int(&e->request); 238 if (response_type != 1) 239 goto failure; 240 241 id = lookup_identity(key, 1); 242 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) { 243 Key *private = id->key; 244 /* Decrypt the challenge using the private key. */ 245 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0) 246 goto failure; 247 248 /* The response is MD5 of decrypted challenge plus session id. */ 249 len = BN_num_bytes(challenge); 250 if (len <= 0 || len > 32) { 251 logit("process_authentication_challenge: bad challenge length %d", len); 252 goto failure; 253 } 254 memset(buf, 0, 32); 255 BN_bn2bin(challenge, buf + 32 - len); 256 MD5_Init(&md); 257 MD5_Update(&md, buf, 32); 258 MD5_Update(&md, session_id, 16); 259 MD5_Final(mdbuf, &md); 260 261 /* Send the response. */ 262 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE); 263 for (i = 0; i < 16; i++) 264 buffer_put_char(&msg, mdbuf[i]); 265 goto send; 266 } 267 268 failure: 269 /* Unknown identity or protocol error. Send failure. */ 270 buffer_put_char(&msg, SSH_AGENT_FAILURE); 271 send: 272 buffer_put_int(&e->output, buffer_len(&msg)); 273 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 274 key_free(key); 275 BN_clear_free(challenge); 276 buffer_free(&msg); 277 } 278 279 /* ssh2 only */ 280 static void 281 process_sign_request2(SocketEntry *e) 282 { 283 u_char *blob, *data, *signature = NULL; 284 u_int blen, dlen, slen = 0; 285 extern int datafellows; 286 int ok = -1, flags; 287 Buffer msg; 288 Key *key; 289 290 datafellows = 0; 291 292 blob = buffer_get_string(&e->request, &blen); 293 data = buffer_get_string(&e->request, &dlen); 294 295 flags = buffer_get_int(&e->request); 296 if (flags & SSH_AGENT_OLD_SIGNATURE) 297 datafellows = SSH_BUG_SIGBLOB; 298 299 key = key_from_blob(blob, blen); 300 if (key != NULL) { 301 Identity *id = lookup_identity(key, 2); 302 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) 303 ok = key_sign(id->key, &signature, &slen, data, dlen); 304 } 305 key_free(key); 306 buffer_init(&msg); 307 if (ok == 0) { 308 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); 309 buffer_put_string(&msg, signature, slen); 310 } else { 311 buffer_put_char(&msg, SSH_AGENT_FAILURE); 312 } 313 buffer_put_int(&e->output, buffer_len(&msg)); 314 buffer_append(&e->output, buffer_ptr(&msg), 315 buffer_len(&msg)); 316 buffer_free(&msg); 317 xfree(data); 318 xfree(blob); 319 if (signature != NULL) 320 xfree(signature); 321 } 322 323 /* shared */ 324 static void 325 process_remove_identity(SocketEntry *e, int version) 326 { 327 u_int blen, bits; 328 int success = 0; 329 Key *key = NULL; 330 u_char *blob; 331 332 switch (version) { 333 case 1: 334 key = key_new(KEY_RSA1); 335 bits = buffer_get_int(&e->request); 336 buffer_get_bignum(&e->request, key->rsa->e); 337 buffer_get_bignum(&e->request, key->rsa->n); 338 339 if (bits != key_size(key)) 340 logit("Warning: identity keysize mismatch: actual %u, announced %u", 341 key_size(key), bits); 342 break; 343 case 2: 344 blob = buffer_get_string(&e->request, &blen); 345 key = key_from_blob(blob, blen); 346 xfree(blob); 347 break; 348 } 349 if (key != NULL) { 350 Identity *id = lookup_identity(key, version); 351 if (id != NULL) { 352 /* 353 * We have this key. Free the old key. Since we 354 * don\'t want to leave empty slots in the middle of 355 * the array, we actually free the key there and move 356 * all the entries between the empty slot and the end 357 * of the array. 358 */ 359 Idtab *tab = idtab_lookup(version); 360 if (tab->nentries < 1) 361 fatal("process_remove_identity: " 362 "internal error: tab->nentries %d", 363 tab->nentries); 364 TAILQ_REMOVE(&tab->idlist, id, next); 365 free_identity(id); 366 tab->nentries--; 367 success = 1; 368 } 369 key_free(key); 370 } 371 buffer_put_int(&e->output, 1); 372 buffer_put_char(&e->output, 373 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 374 } 375 376 static void 377 process_remove_all_identities(SocketEntry *e, int version) 378 { 379 Idtab *tab = idtab_lookup(version); 380 Identity *id; 381 382 /* Loop over all identities and clear the keys. */ 383 for (id = TAILQ_FIRST(&tab->idlist); id; 384 id = TAILQ_FIRST(&tab->idlist)) { 385 TAILQ_REMOVE(&tab->idlist, id, next); 386 free_identity(id); 387 } 388 389 /* Mark that there are no identities. */ 390 tab->nentries = 0; 391 392 /* Send success. */ 393 buffer_put_int(&e->output, 1); 394 buffer_put_char(&e->output, SSH_AGENT_SUCCESS); 395 } 396 397 static void 398 reaper(void) 399 { 400 u_int now = time(NULL); 401 Identity *id, *nxt; 402 int version; 403 Idtab *tab; 404 405 for (version = 1; version < 3; version++) { 406 tab = idtab_lookup(version); 407 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 408 nxt = TAILQ_NEXT(id, next); 409 if (id->death != 0 && now >= id->death) { 410 TAILQ_REMOVE(&tab->idlist, id, next); 411 free_identity(id); 412 tab->nentries--; 413 } 414 } 415 } 416 } 417 418 static void 419 process_add_identity(SocketEntry *e, int version) 420 { 421 Idtab *tab = idtab_lookup(version); 422 int type, success = 0, death = 0, confirm = 0; 423 char *type_name, *comment; 424 Key *k = NULL; 425 426 switch (version) { 427 case 1: 428 k = key_new_private(KEY_RSA1); 429 (void) buffer_get_int(&e->request); /* ignored */ 430 buffer_get_bignum(&e->request, k->rsa->n); 431 buffer_get_bignum(&e->request, k->rsa->e); 432 buffer_get_bignum(&e->request, k->rsa->d); 433 buffer_get_bignum(&e->request, k->rsa->iqmp); 434 435 /* SSH and SSL have p and q swapped */ 436 buffer_get_bignum(&e->request, k->rsa->q); /* p */ 437 buffer_get_bignum(&e->request, k->rsa->p); /* q */ 438 439 /* Generate additional parameters */ 440 rsa_generate_additional_parameters(k->rsa); 441 break; 442 case 2: 443 type_name = buffer_get_string(&e->request, NULL); 444 type = key_type_from_name(type_name); 445 xfree(type_name); 446 switch (type) { 447 case KEY_DSA: 448 k = key_new_private(type); 449 buffer_get_bignum2(&e->request, k->dsa->p); 450 buffer_get_bignum2(&e->request, k->dsa->q); 451 buffer_get_bignum2(&e->request, k->dsa->g); 452 buffer_get_bignum2(&e->request, k->dsa->pub_key); 453 buffer_get_bignum2(&e->request, k->dsa->priv_key); 454 break; 455 case KEY_RSA: 456 k = key_new_private(type); 457 buffer_get_bignum2(&e->request, k->rsa->n); 458 buffer_get_bignum2(&e->request, k->rsa->e); 459 buffer_get_bignum2(&e->request, k->rsa->d); 460 buffer_get_bignum2(&e->request, k->rsa->iqmp); 461 buffer_get_bignum2(&e->request, k->rsa->p); 462 buffer_get_bignum2(&e->request, k->rsa->q); 463 464 /* Generate additional parameters */ 465 rsa_generate_additional_parameters(k->rsa); 466 break; 467 default: 468 buffer_clear(&e->request); 469 goto send; 470 } 471 break; 472 } 473 /* enable blinding */ 474 switch (k->type) { 475 case KEY_RSA: 476 case KEY_RSA1: 477 if (RSA_blinding_on(k->rsa, NULL) != 1) { 478 error("process_add_identity: RSA_blinding_on failed"); 479 key_free(k); 480 goto send; 481 } 482 break; 483 } 484 comment = buffer_get_string(&e->request, NULL); 485 if (k == NULL) { 486 xfree(comment); 487 goto send; 488 } 489 success = 1; 490 while (buffer_len(&e->request)) { 491 switch (buffer_get_char(&e->request)) { 492 case SSH_AGENT_CONSTRAIN_LIFETIME: 493 death = time(NULL) + buffer_get_int(&e->request); 494 break; 495 case SSH_AGENT_CONSTRAIN_CONFIRM: 496 confirm = 1; 497 break; 498 default: 499 break; 500 } 501 } 502 if (lifetime && !death) 503 death = time(NULL) + lifetime; 504 if (lookup_identity(k, version) == NULL) { 505 Identity *id = xmalloc(sizeof(Identity)); 506 id->key = k; 507 id->comment = comment; 508 id->death = death; 509 id->confirm = confirm; 510 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 511 /* Increment the number of identities. */ 512 tab->nentries++; 513 } else { 514 key_free(k); 515 xfree(comment); 516 } 517 send: 518 buffer_put_int(&e->output, 1); 519 buffer_put_char(&e->output, 520 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 521 } 522 523 /* XXX todo: encrypt sensitive data with passphrase */ 524 static void 525 process_lock_agent(SocketEntry *e, int lock) 526 { 527 int success = 0; 528 char *passwd; 529 530 passwd = buffer_get_string(&e->request, NULL); 531 if (locked && !lock && strcmp(passwd, lock_passwd) == 0) { 532 locked = 0; 533 memset(lock_passwd, 0, strlen(lock_passwd)); 534 xfree(lock_passwd); 535 lock_passwd = NULL; 536 success = 1; 537 } else if (!locked && lock) { 538 locked = 1; 539 lock_passwd = xstrdup(passwd); 540 success = 1; 541 } 542 memset(passwd, 0, strlen(passwd)); 543 xfree(passwd); 544 545 buffer_put_int(&e->output, 1); 546 buffer_put_char(&e->output, 547 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 548 } 549 550 static void 551 no_identities(SocketEntry *e, u_int type) 552 { 553 Buffer msg; 554 555 buffer_init(&msg); 556 buffer_put_char(&msg, 557 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ? 558 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 559 buffer_put_int(&msg, 0); 560 buffer_put_int(&e->output, buffer_len(&msg)); 561 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 562 buffer_free(&msg); 563 } 564 565 #ifdef SMARTCARD 566 static void 567 process_add_smartcard_key (SocketEntry *e) 568 { 569 char *sc_reader_id = NULL, *pin; 570 int i, version, success = 0, death = 0, confirm = 0; 571 Key **keys, *k; 572 Identity *id; 573 Idtab *tab; 574 575 sc_reader_id = buffer_get_string(&e->request, NULL); 576 pin = buffer_get_string(&e->request, NULL); 577 578 while (buffer_len(&e->request)) { 579 switch (buffer_get_char(&e->request)) { 580 case SSH_AGENT_CONSTRAIN_LIFETIME: 581 death = time(NULL) + buffer_get_int(&e->request); 582 break; 583 case SSH_AGENT_CONSTRAIN_CONFIRM: 584 confirm = 1; 585 break; 586 default: 587 break; 588 } 589 } 590 if (lifetime && !death) 591 death = time(NULL) + lifetime; 592 593 keys = sc_get_keys(sc_reader_id, pin); 594 xfree(sc_reader_id); 595 xfree(pin); 596 597 if (keys == NULL || keys[0] == NULL) { 598 error("sc_get_keys failed"); 599 goto send; 600 } 601 for (i = 0; keys[i] != NULL; i++) { 602 k = keys[i]; 603 version = k->type == KEY_RSA1 ? 1 : 2; 604 tab = idtab_lookup(version); 605 if (lookup_identity(k, version) == NULL) { 606 id = xmalloc(sizeof(Identity)); 607 id->key = k; 608 id->comment = sc_get_key_label(k); 609 id->death = death; 610 id->confirm = confirm; 611 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 612 tab->nentries++; 613 success = 1; 614 } else { 615 key_free(k); 616 } 617 keys[i] = NULL; 618 } 619 xfree(keys); 620 send: 621 buffer_put_int(&e->output, 1); 622 buffer_put_char(&e->output, 623 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 624 } 625 626 static void 627 process_remove_smartcard_key(SocketEntry *e) 628 { 629 char *sc_reader_id = NULL, *pin; 630 int i, version, success = 0; 631 Key **keys, *k = NULL; 632 Identity *id; 633 Idtab *tab; 634 635 sc_reader_id = buffer_get_string(&e->request, NULL); 636 pin = buffer_get_string(&e->request, NULL); 637 keys = sc_get_keys(sc_reader_id, pin); 638 xfree(sc_reader_id); 639 xfree(pin); 640 641 if (keys == NULL || keys[0] == NULL) { 642 error("sc_get_keys failed"); 643 goto send; 644 } 645 for (i = 0; keys[i] != NULL; i++) { 646 k = keys[i]; 647 version = k->type == KEY_RSA1 ? 1 : 2; 648 if ((id = lookup_identity(k, version)) != NULL) { 649 tab = idtab_lookup(version); 650 TAILQ_REMOVE(&tab->idlist, id, next); 651 tab->nentries--; 652 free_identity(id); 653 success = 1; 654 } 655 key_free(k); 656 keys[i] = NULL; 657 } 658 xfree(keys); 659 send: 660 buffer_put_int(&e->output, 1); 661 buffer_put_char(&e->output, 662 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 663 } 664 #endif /* SMARTCARD */ 665 666 /* dispatch incoming messages */ 667 668 static void 669 process_message(SocketEntry *e) 670 { 671 u_int msg_len, type; 672 u_char *cp; 673 674 /* kill dead keys */ 675 reaper(); 676 677 if (buffer_len(&e->input) < 5) 678 return; /* Incomplete message. */ 679 cp = buffer_ptr(&e->input); 680 msg_len = GET_32BIT(cp); 681 if (msg_len > 256 * 1024) { 682 close_socket(e); 683 return; 684 } 685 if (buffer_len(&e->input) < msg_len + 4) 686 return; 687 688 /* move the current input to e->request */ 689 buffer_consume(&e->input, 4); 690 buffer_clear(&e->request); 691 buffer_append(&e->request, buffer_ptr(&e->input), msg_len); 692 buffer_consume(&e->input, msg_len); 693 type = buffer_get_char(&e->request); 694 695 /* check wheter agent is locked */ 696 if (locked && type != SSH_AGENTC_UNLOCK) { 697 buffer_clear(&e->request); 698 switch (type) { 699 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 700 case SSH2_AGENTC_REQUEST_IDENTITIES: 701 /* send empty lists */ 702 no_identities(e, type); 703 break; 704 default: 705 /* send a fail message for all other request types */ 706 buffer_put_int(&e->output, 1); 707 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 708 } 709 return; 710 } 711 712 debug("type %d", type); 713 switch (type) { 714 case SSH_AGENTC_LOCK: 715 case SSH_AGENTC_UNLOCK: 716 process_lock_agent(e, type == SSH_AGENTC_LOCK); 717 break; 718 /* ssh1 */ 719 case SSH_AGENTC_RSA_CHALLENGE: 720 process_authentication_challenge1(e); 721 break; 722 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 723 process_request_identities(e, 1); 724 break; 725 case SSH_AGENTC_ADD_RSA_IDENTITY: 726 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 727 process_add_identity(e, 1); 728 break; 729 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 730 process_remove_identity(e, 1); 731 break; 732 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 733 process_remove_all_identities(e, 1); 734 break; 735 /* ssh2 */ 736 case SSH2_AGENTC_SIGN_REQUEST: 737 process_sign_request2(e); 738 break; 739 case SSH2_AGENTC_REQUEST_IDENTITIES: 740 process_request_identities(e, 2); 741 break; 742 case SSH2_AGENTC_ADD_IDENTITY: 743 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 744 process_add_identity(e, 2); 745 break; 746 case SSH2_AGENTC_REMOVE_IDENTITY: 747 process_remove_identity(e, 2); 748 break; 749 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 750 process_remove_all_identities(e, 2); 751 break; 752 #ifdef SMARTCARD 753 case SSH_AGENTC_ADD_SMARTCARD_KEY: 754 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 755 process_add_smartcard_key(e); 756 break; 757 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 758 process_remove_smartcard_key(e); 759 break; 760 #endif /* SMARTCARD */ 761 default: 762 /* Unknown message. Respond with failure. */ 763 error("Unknown message %d", type); 764 buffer_clear(&e->request); 765 buffer_put_int(&e->output, 1); 766 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 767 break; 768 } 769 } 770 771 static void 772 new_socket(sock_type type, int fd) 773 { 774 u_int i, old_alloc, new_alloc; 775 776 set_nonblock(fd); 777 778 if (fd > max_fd) 779 max_fd = fd; 780 781 for (i = 0; i < sockets_alloc; i++) 782 if (sockets[i].type == AUTH_UNUSED) { 783 sockets[i].fd = fd; 784 buffer_init(&sockets[i].input); 785 buffer_init(&sockets[i].output); 786 buffer_init(&sockets[i].request); 787 sockets[i].type = type; 788 return; 789 } 790 old_alloc = sockets_alloc; 791 new_alloc = sockets_alloc + 10; 792 if (sockets) 793 sockets = xrealloc(sockets, new_alloc * sizeof(sockets[0])); 794 else 795 sockets = xmalloc(new_alloc * sizeof(sockets[0])); 796 for (i = old_alloc; i < new_alloc; i++) 797 sockets[i].type = AUTH_UNUSED; 798 sockets_alloc = new_alloc; 799 sockets[old_alloc].fd = fd; 800 buffer_init(&sockets[old_alloc].input); 801 buffer_init(&sockets[old_alloc].output); 802 buffer_init(&sockets[old_alloc].request); 803 sockets[old_alloc].type = type; 804 } 805 806 static int 807 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp) 808 { 809 u_int i, sz; 810 int n = 0; 811 812 for (i = 0; i < sockets_alloc; i++) { 813 switch (sockets[i].type) { 814 case AUTH_SOCKET: 815 case AUTH_CONNECTION: 816 n = MAX(n, sockets[i].fd); 817 break; 818 case AUTH_UNUSED: 819 break; 820 default: 821 fatal("Unknown socket type %d", sockets[i].type); 822 break; 823 } 824 } 825 826 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 827 if (*fdrp == NULL || sz > *nallocp) { 828 if (*fdrp) 829 xfree(*fdrp); 830 if (*fdwp) 831 xfree(*fdwp); 832 *fdrp = xmalloc(sz); 833 *fdwp = xmalloc(sz); 834 *nallocp = sz; 835 } 836 if (n < *fdl) 837 debug("XXX shrink: %d < %d", n, *fdl); 838 *fdl = n; 839 memset(*fdrp, 0, sz); 840 memset(*fdwp, 0, sz); 841 842 for (i = 0; i < sockets_alloc; i++) { 843 switch (sockets[i].type) { 844 case AUTH_SOCKET: 845 case AUTH_CONNECTION: 846 FD_SET(sockets[i].fd, *fdrp); 847 if (buffer_len(&sockets[i].output) > 0) 848 FD_SET(sockets[i].fd, *fdwp); 849 break; 850 default: 851 break; 852 } 853 } 854 return (1); 855 } 856 857 static void 858 after_select(fd_set *readset, fd_set *writeset) 859 { 860 struct sockaddr_un sunaddr; 861 socklen_t slen; 862 char buf[1024]; 863 int len, sock; 864 u_int i; 865 uid_t euid; 866 gid_t egid; 867 868 for (i = 0; i < sockets_alloc; i++) 869 switch (sockets[i].type) { 870 case AUTH_UNUSED: 871 break; 872 case AUTH_SOCKET: 873 if (FD_ISSET(sockets[i].fd, readset)) { 874 slen = sizeof(sunaddr); 875 sock = accept(sockets[i].fd, 876 (struct sockaddr *) &sunaddr, &slen); 877 if (sock < 0) { 878 error("accept from AUTH_SOCKET: %s", 879 strerror(errno)); 880 break; 881 } 882 if (getpeereid(sock, &euid, &egid) < 0) { 883 error("getpeereid %d failed: %s", 884 sock, strerror(errno)); 885 close(sock); 886 break; 887 } 888 if ((euid != 0) && (getuid() != euid)) { 889 error("uid mismatch: " 890 "peer euid %u != uid %u", 891 (u_int) euid, (u_int) getuid()); 892 close(sock); 893 break; 894 } 895 new_socket(AUTH_CONNECTION, sock); 896 } 897 break; 898 case AUTH_CONNECTION: 899 if (buffer_len(&sockets[i].output) > 0 && 900 FD_ISSET(sockets[i].fd, writeset)) { 901 do { 902 len = write(sockets[i].fd, 903 buffer_ptr(&sockets[i].output), 904 buffer_len(&sockets[i].output)); 905 if (len == -1 && (errno == EAGAIN || 906 errno == EINTR)) 907 continue; 908 break; 909 } while (1); 910 if (len <= 0) { 911 close_socket(&sockets[i]); 912 break; 913 } 914 buffer_consume(&sockets[i].output, len); 915 } 916 if (FD_ISSET(sockets[i].fd, readset)) { 917 do { 918 len = read(sockets[i].fd, buf, sizeof(buf)); 919 if (len == -1 && (errno == EAGAIN || 920 errno == EINTR)) 921 continue; 922 break; 923 } while (1); 924 if (len <= 0) { 925 close_socket(&sockets[i]); 926 break; 927 } 928 buffer_append(&sockets[i].input, buf, len); 929 process_message(&sockets[i]); 930 } 931 break; 932 default: 933 fatal("Unknown type %d", sockets[i].type); 934 } 935 } 936 937 static void 938 cleanup_socket(void) 939 { 940 if (socket_name[0]) 941 unlink(socket_name); 942 if (socket_dir[0]) 943 rmdir(socket_dir); 944 } 945 946 void 947 cleanup_exit(int i) 948 { 949 cleanup_socket(); 950 _exit(i); 951 } 952 953 static void 954 cleanup_handler(int sig) 955 { 956 cleanup_socket(); 957 _exit(2); 958 } 959 960 static void 961 check_parent_exists(int sig) 962 { 963 int save_errno = errno; 964 965 if (parent_pid != -1 && kill(parent_pid, 0) < 0) { 966 /* printf("Parent has died - Authentication agent exiting.\n"); */ 967 cleanup_handler(sig); /* safe */ 968 } 969 signal(SIGALRM, check_parent_exists); 970 alarm(10); 971 errno = save_errno; 972 } 973 974 static void 975 usage(void) 976 { 977 fprintf(stderr, "Usage: %s [options] [command [args ...]]\n", 978 __progname); 979 fprintf(stderr, "Options:\n"); 980 fprintf(stderr, " -c Generate C-shell commands on stdout.\n"); 981 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n"); 982 fprintf(stderr, " -k Kill the current agent.\n"); 983 fprintf(stderr, " -d Debug mode.\n"); 984 fprintf(stderr, " -a socket Bind agent socket to given name.\n"); 985 fprintf(stderr, " -t life Default identity lifetime (seconds).\n"); 986 exit(1); 987 } 988 989 int 990 main(int ac, char **av) 991 { 992 int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0; 993 int sock, fd, ch; 994 u_int nalloc; 995 char *shell, *format, *pidstr, *agentsocket = NULL; 996 fd_set *readsetp = NULL, *writesetp = NULL; 997 struct sockaddr_un sunaddr; 998 struct rlimit rlim; 999 extern int optind; 1000 extern char *optarg; 1001 pid_t pid; 1002 char pidstrbuf[1 + 3 * sizeof pid]; 1003 1004 /* drop */ 1005 setegid(getgid()); 1006 setgid(getgid()); 1007 1008 SSLeay_add_all_algorithms(); 1009 1010 while ((ch = getopt(ac, av, "cdksa:t:")) != -1) { 1011 switch (ch) { 1012 case 'c': 1013 if (s_flag) 1014 usage(); 1015 c_flag++; 1016 break; 1017 case 'k': 1018 k_flag++; 1019 break; 1020 case 's': 1021 if (c_flag) 1022 usage(); 1023 s_flag++; 1024 break; 1025 case 'd': 1026 if (d_flag) 1027 usage(); 1028 d_flag++; 1029 break; 1030 case 'a': 1031 agentsocket = optarg; 1032 break; 1033 case 't': 1034 if ((lifetime = convtime(optarg)) == -1) { 1035 fprintf(stderr, "Invalid lifetime\n"); 1036 usage(); 1037 } 1038 break; 1039 default: 1040 usage(); 1041 } 1042 } 1043 ac -= optind; 1044 av += optind; 1045 1046 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag)) 1047 usage(); 1048 1049 if (ac == 0 && !c_flag && !s_flag) { 1050 shell = getenv("SHELL"); 1051 if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0) 1052 c_flag = 1; 1053 } 1054 if (k_flag) { 1055 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1056 if (pidstr == NULL) { 1057 fprintf(stderr, "%s not set, cannot kill agent\n", 1058 SSH_AGENTPID_ENV_NAME); 1059 exit(1); 1060 } 1061 pid = atoi(pidstr); 1062 if (pid < 1) { 1063 fprintf(stderr, "%s=\"%s\", which is not a good PID\n", 1064 SSH_AGENTPID_ENV_NAME, pidstr); 1065 exit(1); 1066 } 1067 if (kill(pid, SIGTERM) == -1) { 1068 perror("kill"); 1069 exit(1); 1070 } 1071 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 1072 printf(format, SSH_AUTHSOCKET_ENV_NAME); 1073 printf(format, SSH_AGENTPID_ENV_NAME); 1074 printf("echo Agent pid %ld killed;\n", (long)pid); 1075 exit(0); 1076 } 1077 parent_pid = getpid(); 1078 1079 if (agentsocket == NULL) { 1080 /* Create private directory for agent socket */ 1081 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXXXX", sizeof socket_dir); 1082 if (mkdtemp(socket_dir) == NULL) { 1083 perror("mkdtemp: private socket dir"); 1084 exit(1); 1085 } 1086 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1087 (long)parent_pid); 1088 } else { 1089 /* Try to use specified agent socket */ 1090 socket_dir[0] = '\0'; 1091 strlcpy(socket_name, agentsocket, sizeof socket_name); 1092 } 1093 1094 /* 1095 * Create socket early so it will exist before command gets run from 1096 * the parent. 1097 */ 1098 sock = socket(AF_UNIX, SOCK_STREAM, 0); 1099 if (sock < 0) { 1100 perror("socket"); 1101 *socket_name = '\0'; /* Don't unlink any existing file */ 1102 cleanup_exit(1); 1103 } 1104 memset(&sunaddr, 0, sizeof(sunaddr)); 1105 sunaddr.sun_family = AF_UNIX; 1106 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); 1107 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) { 1108 perror("bind"); 1109 *socket_name = '\0'; /* Don't unlink any existing file */ 1110 cleanup_exit(1); 1111 } 1112 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 1113 perror("listen"); 1114 cleanup_exit(1); 1115 } 1116 1117 /* 1118 * Fork, and have the parent execute the command, if any, or present 1119 * the socket data. The child continues as the authentication agent. 1120 */ 1121 if (d_flag) { 1122 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1); 1123 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1124 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1125 SSH_AUTHSOCKET_ENV_NAME); 1126 printf("echo Agent pid %ld;\n", (long)parent_pid); 1127 goto skip; 1128 } 1129 pid = fork(); 1130 if (pid == -1) { 1131 perror("fork"); 1132 cleanup_exit(1); 1133 } 1134 if (pid != 0) { /* Parent - execute the given command. */ 1135 close(sock); 1136 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1137 if (ac == 0) { 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(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 1142 SSH_AGENTPID_ENV_NAME); 1143 printf("echo Agent pid %ld;\n", (long)pid); 1144 exit(0); 1145 } 1146 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1147 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1148 perror("setenv"); 1149 exit(1); 1150 } 1151 execvp(av[0], av); 1152 perror(av[0]); 1153 exit(1); 1154 } 1155 /* child */ 1156 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1157 1158 if (setsid() == -1) { 1159 error("setsid: %s", strerror(errno)); 1160 cleanup_exit(1); 1161 } 1162 1163 (void)chdir("/"); 1164 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1165 /* XXX might close listen socket */ 1166 (void)dup2(fd, STDIN_FILENO); 1167 (void)dup2(fd, STDOUT_FILENO); 1168 (void)dup2(fd, STDERR_FILENO); 1169 if (fd > 2) 1170 close(fd); 1171 } 1172 1173 /* deny core dumps, since memory contains unencrypted private keys */ 1174 rlim.rlim_cur = rlim.rlim_max = 0; 1175 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 1176 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1177 cleanup_exit(1); 1178 } 1179 1180 skip: 1181 new_socket(AUTH_SOCKET, sock); 1182 if (ac > 0) { 1183 signal(SIGALRM, check_parent_exists); 1184 alarm(10); 1185 } 1186 idtab_init(); 1187 if (!d_flag) 1188 signal(SIGINT, SIG_IGN); 1189 signal(SIGPIPE, SIG_IGN); 1190 signal(SIGHUP, cleanup_handler); 1191 signal(SIGTERM, cleanup_handler); 1192 nalloc = 0; 1193 1194 while (1) { 1195 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc); 1196 if (select(max_fd + 1, readsetp, writesetp, NULL, NULL) < 0) { 1197 if (errno == EINTR) 1198 continue; 1199 fatal("select: %s", strerror(errno)); 1200 } 1201 after_select(readsetp, writesetp); 1202 } 1203 /* NOTREACHED */ 1204 } 1205