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 "openbsd-compat/sys-queue.h" 38 RCSID("$OpenBSD: ssh-agent.c,v 1.117 2003/12/02 17:01:15 markus Exp $"); 39 RCSID("$FreeBSD$"); 40 41 #include <openssl/evp.h> 42 #include <openssl/md5.h> 43 44 #include "ssh.h" 45 #include "rsa.h" 46 #include "buffer.h" 47 #include "bufaux.h" 48 #include "xmalloc.h" 49 #include "getput.h" 50 #include "key.h" 51 #include "authfd.h" 52 #include "compat.h" 53 #include "log.h" 54 #include "readpass.h" 55 #include "misc.h" 56 57 #ifdef SMARTCARD 58 #include "scard.h" 59 #endif 60 61 typedef enum { 62 AUTH_UNUSED, 63 AUTH_SOCKET, 64 AUTH_CONNECTION 65 } sock_type; 66 67 typedef struct { 68 int fd; 69 sock_type type; 70 Buffer input; 71 Buffer output; 72 Buffer request; 73 } SocketEntry; 74 75 u_int sockets_alloc = 0; 76 SocketEntry *sockets = NULL; 77 78 typedef struct identity { 79 TAILQ_ENTRY(identity) next; 80 Key *key; 81 char *comment; 82 u_int death; 83 u_int confirm; 84 } Identity; 85 86 typedef struct { 87 int nentries; 88 TAILQ_HEAD(idqueue, identity) idlist; 89 } Idtab; 90 91 /* private key table, one per protocol version */ 92 Idtab idtable[3]; 93 94 int max_fd = 0; 95 96 /* pid of shell == parent of agent */ 97 pid_t parent_pid = -1; 98 99 /* pathname and directory for AUTH_SOCKET */ 100 char socket_name[1024]; 101 char socket_dir[1024]; 102 103 /* locking */ 104 int locked = 0; 105 char *lock_passwd = NULL; 106 107 #ifdef HAVE___PROGNAME 108 extern char *__progname; 109 #else 110 char *__progname; 111 #endif 112 113 /* Default lifetime (0 == forever) */ 114 static int lifetime = 0; 115 116 static void 117 close_socket(SocketEntry *e) 118 { 119 close(e->fd); 120 e->fd = -1; 121 e->type = AUTH_UNUSED; 122 buffer_free(&e->input); 123 buffer_free(&e->output); 124 buffer_free(&e->request); 125 } 126 127 static void 128 idtab_init(void) 129 { 130 int i; 131 132 for (i = 0; i <=2; i++) { 133 TAILQ_INIT(&idtable[i].idlist); 134 idtable[i].nentries = 0; 135 } 136 } 137 138 /* return private key table for requested protocol version */ 139 static Idtab * 140 idtab_lookup(int version) 141 { 142 if (version < 1 || version > 2) 143 fatal("internal error, bad protocol version %d", version); 144 return &idtable[version]; 145 } 146 147 static void 148 free_identity(Identity *id) 149 { 150 key_free(id->key); 151 xfree(id->comment); 152 xfree(id); 153 } 154 155 /* return matching private key for given public key */ 156 static Identity * 157 lookup_identity(Key *key, int version) 158 { 159 Identity *id; 160 161 Idtab *tab = idtab_lookup(version); 162 TAILQ_FOREACH(id, &tab->idlist, next) { 163 if (key_equal(key, id->key)) 164 return (id); 165 } 166 return (NULL); 167 } 168 169 /* Check confirmation of keysign request */ 170 static int 171 confirm_key(Identity *id) 172 { 173 char *p, prompt[1024]; 174 int ret = -1; 175 176 p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX); 177 snprintf(prompt, sizeof(prompt), "Allow use of key %s?\n" 178 "Key fingerprint %s.", id->comment, p); 179 xfree(p); 180 p = read_passphrase(prompt, RP_ALLOW_EOF); 181 if (p != NULL) { 182 /* 183 * Accept empty responses and responses consisting 184 * of the word "yes" as affirmative. 185 */ 186 if (*p == '\0' || *p == '\n' || strcasecmp(p, "yes") == 0) 187 ret = 0; 188 xfree(p); 189 } 190 return (ret); 191 } 192 193 /* send list of supported public keys to 'client' */ 194 static void 195 process_request_identities(SocketEntry *e, int version) 196 { 197 Idtab *tab = idtab_lookup(version); 198 Identity *id; 199 Buffer msg; 200 201 buffer_init(&msg); 202 buffer_put_char(&msg, (version == 1) ? 203 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 204 buffer_put_int(&msg, tab->nentries); 205 TAILQ_FOREACH(id, &tab->idlist, next) { 206 if (id->key->type == KEY_RSA1) { 207 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n)); 208 buffer_put_bignum(&msg, id->key->rsa->e); 209 buffer_put_bignum(&msg, id->key->rsa->n); 210 } else { 211 u_char *blob; 212 u_int blen; 213 key_to_blob(id->key, &blob, &blen); 214 buffer_put_string(&msg, blob, blen); 215 xfree(blob); 216 } 217 buffer_put_cstring(&msg, id->comment); 218 } 219 buffer_put_int(&e->output, buffer_len(&msg)); 220 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 221 buffer_free(&msg); 222 } 223 224 /* ssh1 only */ 225 static void 226 process_authentication_challenge1(SocketEntry *e) 227 { 228 u_char buf[32], mdbuf[16], session_id[16]; 229 u_int response_type; 230 BIGNUM *challenge; 231 Identity *id; 232 int i, len; 233 Buffer msg; 234 MD5_CTX md; 235 Key *key; 236 237 buffer_init(&msg); 238 key = key_new(KEY_RSA1); 239 if ((challenge = BN_new()) == NULL) 240 fatal("process_authentication_challenge1: BN_new failed"); 241 242 (void) buffer_get_int(&e->request); /* ignored */ 243 buffer_get_bignum(&e->request, key->rsa->e); 244 buffer_get_bignum(&e->request, key->rsa->n); 245 buffer_get_bignum(&e->request, challenge); 246 247 /* Only protocol 1.1 is supported */ 248 if (buffer_len(&e->request) == 0) 249 goto failure; 250 buffer_get(&e->request, session_id, 16); 251 response_type = buffer_get_int(&e->request); 252 if (response_type != 1) 253 goto failure; 254 255 id = lookup_identity(key, 1); 256 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) { 257 Key *private = id->key; 258 /* Decrypt the challenge using the private key. */ 259 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0) 260 goto failure; 261 262 /* The response is MD5 of decrypted challenge plus session id. */ 263 len = BN_num_bytes(challenge); 264 if (len <= 0 || len > 32) { 265 logit("process_authentication_challenge: bad challenge length %d", len); 266 goto failure; 267 } 268 memset(buf, 0, 32); 269 BN_bn2bin(challenge, buf + 32 - len); 270 MD5_Init(&md); 271 MD5_Update(&md, buf, 32); 272 MD5_Update(&md, session_id, 16); 273 MD5_Final(mdbuf, &md); 274 275 /* Send the response. */ 276 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE); 277 for (i = 0; i < 16; i++) 278 buffer_put_char(&msg, mdbuf[i]); 279 goto send; 280 } 281 282 failure: 283 /* Unknown identity or protocol error. Send failure. */ 284 buffer_put_char(&msg, SSH_AGENT_FAILURE); 285 send: 286 buffer_put_int(&e->output, buffer_len(&msg)); 287 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 288 key_free(key); 289 BN_clear_free(challenge); 290 buffer_free(&msg); 291 } 292 293 /* ssh2 only */ 294 static void 295 process_sign_request2(SocketEntry *e) 296 { 297 u_char *blob, *data, *signature = NULL; 298 u_int blen, dlen, slen = 0; 299 extern int datafellows; 300 int ok = -1, flags; 301 Buffer msg; 302 Key *key; 303 304 datafellows = 0; 305 306 blob = buffer_get_string(&e->request, &blen); 307 data = buffer_get_string(&e->request, &dlen); 308 309 flags = buffer_get_int(&e->request); 310 if (flags & SSH_AGENT_OLD_SIGNATURE) 311 datafellows = SSH_BUG_SIGBLOB; 312 313 key = key_from_blob(blob, blen); 314 if (key != NULL) { 315 Identity *id = lookup_identity(key, 2); 316 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) 317 ok = key_sign(id->key, &signature, &slen, data, dlen); 318 } 319 key_free(key); 320 buffer_init(&msg); 321 if (ok == 0) { 322 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); 323 buffer_put_string(&msg, signature, slen); 324 } else { 325 buffer_put_char(&msg, SSH_AGENT_FAILURE); 326 } 327 buffer_put_int(&e->output, buffer_len(&msg)); 328 buffer_append(&e->output, buffer_ptr(&msg), 329 buffer_len(&msg)); 330 buffer_free(&msg); 331 xfree(data); 332 xfree(blob); 333 if (signature != NULL) 334 xfree(signature); 335 } 336 337 /* shared */ 338 static void 339 process_remove_identity(SocketEntry *e, int version) 340 { 341 u_int blen, bits; 342 int success = 0; 343 Key *key = NULL; 344 u_char *blob; 345 346 switch (version) { 347 case 1: 348 key = key_new(KEY_RSA1); 349 bits = buffer_get_int(&e->request); 350 buffer_get_bignum(&e->request, key->rsa->e); 351 buffer_get_bignum(&e->request, key->rsa->n); 352 353 if (bits != key_size(key)) 354 logit("Warning: identity keysize mismatch: actual %u, announced %u", 355 key_size(key), bits); 356 break; 357 case 2: 358 blob = buffer_get_string(&e->request, &blen); 359 key = key_from_blob(blob, blen); 360 xfree(blob); 361 break; 362 } 363 if (key != NULL) { 364 Identity *id = lookup_identity(key, version); 365 if (id != NULL) { 366 /* 367 * We have this key. Free the old key. Since we 368 * don\'t want to leave empty slots in the middle of 369 * the array, we actually free the key there and move 370 * all the entries between the empty slot and the end 371 * of the array. 372 */ 373 Idtab *tab = idtab_lookup(version); 374 if (tab->nentries < 1) 375 fatal("process_remove_identity: " 376 "internal error: tab->nentries %d", 377 tab->nentries); 378 TAILQ_REMOVE(&tab->idlist, id, next); 379 free_identity(id); 380 tab->nentries--; 381 success = 1; 382 } 383 key_free(key); 384 } 385 buffer_put_int(&e->output, 1); 386 buffer_put_char(&e->output, 387 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 388 } 389 390 static void 391 process_remove_all_identities(SocketEntry *e, int version) 392 { 393 Idtab *tab = idtab_lookup(version); 394 Identity *id; 395 396 /* Loop over all identities and clear the keys. */ 397 for (id = TAILQ_FIRST(&tab->idlist); id; 398 id = TAILQ_FIRST(&tab->idlist)) { 399 TAILQ_REMOVE(&tab->idlist, id, next); 400 free_identity(id); 401 } 402 403 /* Mark that there are no identities. */ 404 tab->nentries = 0; 405 406 /* Send success. */ 407 buffer_put_int(&e->output, 1); 408 buffer_put_char(&e->output, SSH_AGENT_SUCCESS); 409 } 410 411 static void 412 reaper(void) 413 { 414 u_int now = time(NULL); 415 Identity *id, *nxt; 416 int version; 417 Idtab *tab; 418 419 for (version = 1; version < 3; version++) { 420 tab = idtab_lookup(version); 421 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 422 nxt = TAILQ_NEXT(id, next); 423 if (id->death != 0 && now >= id->death) { 424 TAILQ_REMOVE(&tab->idlist, id, next); 425 free_identity(id); 426 tab->nentries--; 427 } 428 } 429 } 430 } 431 432 static void 433 process_add_identity(SocketEntry *e, int version) 434 { 435 Idtab *tab = idtab_lookup(version); 436 int type, success = 0, death = 0, confirm = 0; 437 char *type_name, *comment; 438 Key *k = NULL; 439 440 switch (version) { 441 case 1: 442 k = key_new_private(KEY_RSA1); 443 (void) buffer_get_int(&e->request); /* ignored */ 444 buffer_get_bignum(&e->request, k->rsa->n); 445 buffer_get_bignum(&e->request, k->rsa->e); 446 buffer_get_bignum(&e->request, k->rsa->d); 447 buffer_get_bignum(&e->request, k->rsa->iqmp); 448 449 /* SSH and SSL have p and q swapped */ 450 buffer_get_bignum(&e->request, k->rsa->q); /* p */ 451 buffer_get_bignum(&e->request, k->rsa->p); /* q */ 452 453 /* Generate additional parameters */ 454 rsa_generate_additional_parameters(k->rsa); 455 break; 456 case 2: 457 type_name = buffer_get_string(&e->request, NULL); 458 type = key_type_from_name(type_name); 459 xfree(type_name); 460 switch (type) { 461 case KEY_DSA: 462 k = key_new_private(type); 463 buffer_get_bignum2(&e->request, k->dsa->p); 464 buffer_get_bignum2(&e->request, k->dsa->q); 465 buffer_get_bignum2(&e->request, k->dsa->g); 466 buffer_get_bignum2(&e->request, k->dsa->pub_key); 467 buffer_get_bignum2(&e->request, k->dsa->priv_key); 468 break; 469 case KEY_RSA: 470 k = key_new_private(type); 471 buffer_get_bignum2(&e->request, k->rsa->n); 472 buffer_get_bignum2(&e->request, k->rsa->e); 473 buffer_get_bignum2(&e->request, k->rsa->d); 474 buffer_get_bignum2(&e->request, k->rsa->iqmp); 475 buffer_get_bignum2(&e->request, k->rsa->p); 476 buffer_get_bignum2(&e->request, k->rsa->q); 477 478 /* Generate additional parameters */ 479 rsa_generate_additional_parameters(k->rsa); 480 break; 481 default: 482 buffer_clear(&e->request); 483 goto send; 484 } 485 break; 486 } 487 /* enable blinding */ 488 switch (k->type) { 489 case KEY_RSA: 490 case KEY_RSA1: 491 if (RSA_blinding_on(k->rsa, NULL) != 1) { 492 error("process_add_identity: RSA_blinding_on failed"); 493 key_free(k); 494 goto send; 495 } 496 break; 497 } 498 comment = buffer_get_string(&e->request, NULL); 499 if (k == NULL) { 500 xfree(comment); 501 goto send; 502 } 503 success = 1; 504 while (buffer_len(&e->request)) { 505 switch (buffer_get_char(&e->request)) { 506 case SSH_AGENT_CONSTRAIN_LIFETIME: 507 death = time(NULL) + buffer_get_int(&e->request); 508 break; 509 case SSH_AGENT_CONSTRAIN_CONFIRM: 510 confirm = 1; 511 break; 512 default: 513 break; 514 } 515 } 516 if (lifetime && !death) 517 death = time(NULL) + lifetime; 518 if (lookup_identity(k, version) == NULL) { 519 Identity *id = xmalloc(sizeof(Identity)); 520 id->key = k; 521 id->comment = comment; 522 id->death = death; 523 id->confirm = confirm; 524 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 525 /* Increment the number of identities. */ 526 tab->nentries++; 527 } else { 528 key_free(k); 529 xfree(comment); 530 } 531 send: 532 buffer_put_int(&e->output, 1); 533 buffer_put_char(&e->output, 534 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 535 } 536 537 /* XXX todo: encrypt sensitive data with passphrase */ 538 static void 539 process_lock_agent(SocketEntry *e, int lock) 540 { 541 int success = 0; 542 char *passwd; 543 544 passwd = buffer_get_string(&e->request, NULL); 545 if (locked && !lock && strcmp(passwd, lock_passwd) == 0) { 546 locked = 0; 547 memset(lock_passwd, 0, strlen(lock_passwd)); 548 xfree(lock_passwd); 549 lock_passwd = NULL; 550 success = 1; 551 } else if (!locked && lock) { 552 locked = 1; 553 lock_passwd = xstrdup(passwd); 554 success = 1; 555 } 556 memset(passwd, 0, strlen(passwd)); 557 xfree(passwd); 558 559 buffer_put_int(&e->output, 1); 560 buffer_put_char(&e->output, 561 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 562 } 563 564 static void 565 no_identities(SocketEntry *e, u_int type) 566 { 567 Buffer msg; 568 569 buffer_init(&msg); 570 buffer_put_char(&msg, 571 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ? 572 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 573 buffer_put_int(&msg, 0); 574 buffer_put_int(&e->output, buffer_len(&msg)); 575 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 576 buffer_free(&msg); 577 } 578 579 #ifdef SMARTCARD 580 static void 581 process_add_smartcard_key (SocketEntry *e) 582 { 583 char *sc_reader_id = NULL, *pin; 584 int i, version, success = 0, death = 0, confirm = 0; 585 Key **keys, *k; 586 Identity *id; 587 Idtab *tab; 588 589 sc_reader_id = buffer_get_string(&e->request, NULL); 590 pin = buffer_get_string(&e->request, NULL); 591 592 while (buffer_len(&e->request)) { 593 switch (buffer_get_char(&e->request)) { 594 case SSH_AGENT_CONSTRAIN_LIFETIME: 595 death = time(NULL) + buffer_get_int(&e->request); 596 break; 597 case SSH_AGENT_CONSTRAIN_CONFIRM: 598 confirm = 1; 599 break; 600 default: 601 break; 602 } 603 } 604 if (lifetime && !death) 605 death = time(NULL) + lifetime; 606 607 keys = sc_get_keys(sc_reader_id, pin); 608 xfree(sc_reader_id); 609 xfree(pin); 610 611 if (keys == NULL || keys[0] == NULL) { 612 error("sc_get_keys failed"); 613 goto send; 614 } 615 for (i = 0; keys[i] != NULL; i++) { 616 k = keys[i]; 617 version = k->type == KEY_RSA1 ? 1 : 2; 618 tab = idtab_lookup(version); 619 if (lookup_identity(k, version) == NULL) { 620 id = xmalloc(sizeof(Identity)); 621 id->key = k; 622 id->comment = sc_get_key_label(k); 623 id->death = death; 624 id->confirm = confirm; 625 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 626 tab->nentries++; 627 success = 1; 628 } else { 629 key_free(k); 630 } 631 keys[i] = NULL; 632 } 633 xfree(keys); 634 send: 635 buffer_put_int(&e->output, 1); 636 buffer_put_char(&e->output, 637 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 638 } 639 640 static void 641 process_remove_smartcard_key(SocketEntry *e) 642 { 643 char *sc_reader_id = NULL, *pin; 644 int i, version, success = 0; 645 Key **keys, *k = NULL; 646 Identity *id; 647 Idtab *tab; 648 649 sc_reader_id = buffer_get_string(&e->request, NULL); 650 pin = buffer_get_string(&e->request, NULL); 651 keys = sc_get_keys(sc_reader_id, pin); 652 xfree(sc_reader_id); 653 xfree(pin); 654 655 if (keys == NULL || keys[0] == NULL) { 656 error("sc_get_keys failed"); 657 goto send; 658 } 659 for (i = 0; keys[i] != NULL; i++) { 660 k = keys[i]; 661 version = k->type == KEY_RSA1 ? 1 : 2; 662 if ((id = lookup_identity(k, version)) != NULL) { 663 tab = idtab_lookup(version); 664 TAILQ_REMOVE(&tab->idlist, id, next); 665 tab->nentries--; 666 free_identity(id); 667 success = 1; 668 } 669 key_free(k); 670 keys[i] = NULL; 671 } 672 xfree(keys); 673 send: 674 buffer_put_int(&e->output, 1); 675 buffer_put_char(&e->output, 676 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 677 } 678 #endif /* SMARTCARD */ 679 680 /* dispatch incoming messages */ 681 682 static void 683 process_message(SocketEntry *e) 684 { 685 u_int msg_len, type; 686 u_char *cp; 687 688 /* kill dead keys */ 689 reaper(); 690 691 if (buffer_len(&e->input) < 5) 692 return; /* Incomplete message. */ 693 cp = buffer_ptr(&e->input); 694 msg_len = GET_32BIT(cp); 695 if (msg_len > 256 * 1024) { 696 close_socket(e); 697 return; 698 } 699 if (buffer_len(&e->input) < msg_len + 4) 700 return; 701 702 /* move the current input to e->request */ 703 buffer_consume(&e->input, 4); 704 buffer_clear(&e->request); 705 buffer_append(&e->request, buffer_ptr(&e->input), msg_len); 706 buffer_consume(&e->input, msg_len); 707 type = buffer_get_char(&e->request); 708 709 /* check wheter agent is locked */ 710 if (locked && type != SSH_AGENTC_UNLOCK) { 711 buffer_clear(&e->request); 712 switch (type) { 713 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 714 case SSH2_AGENTC_REQUEST_IDENTITIES: 715 /* send empty lists */ 716 no_identities(e, type); 717 break; 718 default: 719 /* send a fail message for all other request types */ 720 buffer_put_int(&e->output, 1); 721 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 722 } 723 return; 724 } 725 726 debug("type %d", type); 727 switch (type) { 728 case SSH_AGENTC_LOCK: 729 case SSH_AGENTC_UNLOCK: 730 process_lock_agent(e, type == SSH_AGENTC_LOCK); 731 break; 732 /* ssh1 */ 733 case SSH_AGENTC_RSA_CHALLENGE: 734 process_authentication_challenge1(e); 735 break; 736 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 737 process_request_identities(e, 1); 738 break; 739 case SSH_AGENTC_ADD_RSA_IDENTITY: 740 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 741 process_add_identity(e, 1); 742 break; 743 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 744 process_remove_identity(e, 1); 745 break; 746 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 747 process_remove_all_identities(e, 1); 748 break; 749 /* ssh2 */ 750 case SSH2_AGENTC_SIGN_REQUEST: 751 process_sign_request2(e); 752 break; 753 case SSH2_AGENTC_REQUEST_IDENTITIES: 754 process_request_identities(e, 2); 755 break; 756 case SSH2_AGENTC_ADD_IDENTITY: 757 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 758 process_add_identity(e, 2); 759 break; 760 case SSH2_AGENTC_REMOVE_IDENTITY: 761 process_remove_identity(e, 2); 762 break; 763 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 764 process_remove_all_identities(e, 2); 765 break; 766 #ifdef SMARTCARD 767 case SSH_AGENTC_ADD_SMARTCARD_KEY: 768 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 769 process_add_smartcard_key(e); 770 break; 771 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 772 process_remove_smartcard_key(e); 773 break; 774 #endif /* SMARTCARD */ 775 default: 776 /* Unknown message. Respond with failure. */ 777 error("Unknown message %d", type); 778 buffer_clear(&e->request); 779 buffer_put_int(&e->output, 1); 780 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 781 break; 782 } 783 } 784 785 static void 786 new_socket(sock_type type, int fd) 787 { 788 u_int i, old_alloc, new_alloc; 789 790 if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) 791 error("fcntl O_NONBLOCK: %s", strerror(errno)); 792 793 if (fd > max_fd) 794 max_fd = fd; 795 796 for (i = 0; i < sockets_alloc; i++) 797 if (sockets[i].type == AUTH_UNUSED) { 798 sockets[i].fd = fd; 799 buffer_init(&sockets[i].input); 800 buffer_init(&sockets[i].output); 801 buffer_init(&sockets[i].request); 802 sockets[i].type = type; 803 return; 804 } 805 old_alloc = sockets_alloc; 806 new_alloc = sockets_alloc + 10; 807 if (sockets) 808 sockets = xrealloc(sockets, new_alloc * sizeof(sockets[0])); 809 else 810 sockets = xmalloc(new_alloc * sizeof(sockets[0])); 811 for (i = old_alloc; i < new_alloc; i++) 812 sockets[i].type = AUTH_UNUSED; 813 sockets_alloc = new_alloc; 814 sockets[old_alloc].fd = fd; 815 buffer_init(&sockets[old_alloc].input); 816 buffer_init(&sockets[old_alloc].output); 817 buffer_init(&sockets[old_alloc].request); 818 sockets[old_alloc].type = type; 819 } 820 821 static int 822 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, int *nallocp) 823 { 824 u_int i, sz; 825 int n = 0; 826 827 for (i = 0; i < sockets_alloc; i++) { 828 switch (sockets[i].type) { 829 case AUTH_SOCKET: 830 case AUTH_CONNECTION: 831 n = MAX(n, sockets[i].fd); 832 break; 833 case AUTH_UNUSED: 834 break; 835 default: 836 fatal("Unknown socket type %d", sockets[i].type); 837 break; 838 } 839 } 840 841 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 842 if (*fdrp == NULL || sz > *nallocp) { 843 if (*fdrp) 844 xfree(*fdrp); 845 if (*fdwp) 846 xfree(*fdwp); 847 *fdrp = xmalloc(sz); 848 *fdwp = xmalloc(sz); 849 *nallocp = sz; 850 } 851 if (n < *fdl) 852 debug("XXX shrink: %d < %d", n, *fdl); 853 *fdl = n; 854 memset(*fdrp, 0, sz); 855 memset(*fdwp, 0, sz); 856 857 for (i = 0; i < sockets_alloc; i++) { 858 switch (sockets[i].type) { 859 case AUTH_SOCKET: 860 case AUTH_CONNECTION: 861 FD_SET(sockets[i].fd, *fdrp); 862 if (buffer_len(&sockets[i].output) > 0) 863 FD_SET(sockets[i].fd, *fdwp); 864 break; 865 default: 866 break; 867 } 868 } 869 return (1); 870 } 871 872 static void 873 after_select(fd_set *readset, fd_set *writeset) 874 { 875 struct sockaddr_un sunaddr; 876 socklen_t slen; 877 char buf[1024]; 878 int len, sock; 879 u_int i; 880 uid_t euid; 881 gid_t egid; 882 883 for (i = 0; i < sockets_alloc; i++) 884 switch (sockets[i].type) { 885 case AUTH_UNUSED: 886 break; 887 case AUTH_SOCKET: 888 if (FD_ISSET(sockets[i].fd, readset)) { 889 slen = sizeof(sunaddr); 890 sock = accept(sockets[i].fd, 891 (struct sockaddr *) &sunaddr, &slen); 892 if (sock < 0) { 893 error("accept from AUTH_SOCKET: %s", 894 strerror(errno)); 895 break; 896 } 897 if (getpeereid(sock, &euid, &egid) < 0) { 898 error("getpeereid %d failed: %s", 899 sock, strerror(errno)); 900 close(sock); 901 break; 902 } 903 if ((euid != 0) && (getuid() != euid)) { 904 error("uid mismatch: " 905 "peer euid %u != uid %u", 906 (u_int) euid, (u_int) getuid()); 907 close(sock); 908 break; 909 } 910 new_socket(AUTH_CONNECTION, sock); 911 } 912 break; 913 case AUTH_CONNECTION: 914 if (buffer_len(&sockets[i].output) > 0 && 915 FD_ISSET(sockets[i].fd, writeset)) { 916 do { 917 len = write(sockets[i].fd, 918 buffer_ptr(&sockets[i].output), 919 buffer_len(&sockets[i].output)); 920 if (len == -1 && (errno == EAGAIN || 921 errno == EINTR)) 922 continue; 923 break; 924 } while (1); 925 if (len <= 0) { 926 close_socket(&sockets[i]); 927 break; 928 } 929 buffer_consume(&sockets[i].output, len); 930 } 931 if (FD_ISSET(sockets[i].fd, readset)) { 932 do { 933 len = read(sockets[i].fd, buf, sizeof(buf)); 934 if (len == -1 && (errno == EAGAIN || 935 errno == EINTR)) 936 continue; 937 break; 938 } while (1); 939 if (len <= 0) { 940 close_socket(&sockets[i]); 941 break; 942 } 943 buffer_append(&sockets[i].input, buf, len); 944 process_message(&sockets[i]); 945 } 946 break; 947 default: 948 fatal("Unknown type %d", sockets[i].type); 949 } 950 } 951 952 static void 953 cleanup_socket(void) 954 { 955 if (socket_name[0]) 956 unlink(socket_name); 957 if (socket_dir[0]) 958 rmdir(socket_dir); 959 } 960 961 void 962 cleanup_exit(int i) 963 { 964 cleanup_socket(); 965 _exit(i); 966 } 967 968 static void 969 cleanup_handler(int sig) 970 { 971 cleanup_socket(); 972 _exit(2); 973 } 974 975 static void 976 check_parent_exists(int sig) 977 { 978 int save_errno = errno; 979 980 if (parent_pid != -1 && kill(parent_pid, 0) < 0) { 981 /* printf("Parent has died - Authentication agent exiting.\n"); */ 982 cleanup_handler(sig); /* safe */ 983 } 984 mysignal(SIGALRM, check_parent_exists); 985 alarm(10); 986 errno = save_errno; 987 } 988 989 static void 990 usage(void) 991 { 992 fprintf(stderr, "Usage: %s [options] [command [args ...]]\n", 993 __progname); 994 fprintf(stderr, "Options:\n"); 995 fprintf(stderr, " -c Generate C-shell commands on stdout.\n"); 996 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n"); 997 fprintf(stderr, " -k Kill the current agent.\n"); 998 fprintf(stderr, " -d Debug mode.\n"); 999 fprintf(stderr, " -a socket Bind agent socket to given name.\n"); 1000 fprintf(stderr, " -t life Default identity lifetime (seconds).\n"); 1001 exit(1); 1002 } 1003 1004 int 1005 main(int ac, char **av) 1006 { 1007 int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0; 1008 int sock, fd, ch, nalloc; 1009 char *shell, *format, *pidstr, *agentsocket = NULL; 1010 fd_set *readsetp = NULL, *writesetp = NULL; 1011 struct sockaddr_un sunaddr; 1012 #ifdef HAVE_SETRLIMIT 1013 struct rlimit rlim; 1014 #endif 1015 #ifdef HAVE_CYGWIN 1016 int prev_mask; 1017 #endif 1018 extern int optind; 1019 extern char *optarg; 1020 pid_t pid; 1021 char pidstrbuf[1 + 3 * sizeof pid]; 1022 1023 /* drop */ 1024 setegid(getgid()); 1025 setgid(getgid()); 1026 setuid(geteuid()); 1027 1028 SSLeay_add_all_algorithms(); 1029 1030 __progname = ssh_get_progname(av[0]); 1031 init_rng(); 1032 seed_rng(); 1033 1034 while ((ch = getopt(ac, av, "cdksa:t:")) != -1) { 1035 switch (ch) { 1036 case 'c': 1037 if (s_flag) 1038 usage(); 1039 c_flag++; 1040 break; 1041 case 'k': 1042 k_flag++; 1043 break; 1044 case 's': 1045 if (c_flag) 1046 usage(); 1047 s_flag++; 1048 break; 1049 case 'd': 1050 if (d_flag) 1051 usage(); 1052 d_flag++; 1053 break; 1054 case 'a': 1055 agentsocket = optarg; 1056 break; 1057 case 't': 1058 if ((lifetime = convtime(optarg)) == -1) { 1059 fprintf(stderr, "Invalid lifetime\n"); 1060 usage(); 1061 } 1062 break; 1063 default: 1064 usage(); 1065 } 1066 } 1067 ac -= optind; 1068 av += optind; 1069 1070 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag)) 1071 usage(); 1072 1073 if (ac == 0 && !c_flag && !s_flag) { 1074 shell = getenv("SHELL"); 1075 if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0) 1076 c_flag = 1; 1077 } 1078 if (k_flag) { 1079 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1080 if (pidstr == NULL) { 1081 fprintf(stderr, "%s not set, cannot kill agent\n", 1082 SSH_AGENTPID_ENV_NAME); 1083 exit(1); 1084 } 1085 pid = atoi(pidstr); 1086 if (pid < 1) { 1087 fprintf(stderr, "%s=\"%s\", which is not a good PID\n", 1088 SSH_AGENTPID_ENV_NAME, pidstr); 1089 exit(1); 1090 } 1091 if (kill(pid, SIGTERM) == -1) { 1092 perror("kill"); 1093 exit(1); 1094 } 1095 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 1096 printf(format, SSH_AUTHSOCKET_ENV_NAME); 1097 printf(format, SSH_AGENTPID_ENV_NAME); 1098 printf("echo Agent pid %ld killed;\n", (long)pid); 1099 exit(0); 1100 } 1101 parent_pid = getpid(); 1102 1103 if (agentsocket == NULL) { 1104 /* Create private directory for agent socket */ 1105 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXXXX", sizeof socket_dir); 1106 if (mkdtemp(socket_dir) == NULL) { 1107 perror("mkdtemp: private socket dir"); 1108 exit(1); 1109 } 1110 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1111 (long)parent_pid); 1112 } else { 1113 /* Try to use specified agent socket */ 1114 socket_dir[0] = '\0'; 1115 strlcpy(socket_name, agentsocket, sizeof socket_name); 1116 } 1117 1118 /* 1119 * Create socket early so it will exist before command gets run from 1120 * the parent. 1121 */ 1122 sock = socket(AF_UNIX, SOCK_STREAM, 0); 1123 if (sock < 0) { 1124 perror("socket"); 1125 cleanup_exit(1); 1126 } 1127 memset(&sunaddr, 0, sizeof(sunaddr)); 1128 sunaddr.sun_family = AF_UNIX; 1129 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); 1130 #ifdef HAVE_CYGWIN 1131 prev_mask = umask(0177); 1132 #endif 1133 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) { 1134 perror("bind"); 1135 #ifdef HAVE_CYGWIN 1136 umask(prev_mask); 1137 #endif 1138 cleanup_exit(1); 1139 } 1140 #ifdef HAVE_CYGWIN 1141 umask(prev_mask); 1142 #endif 1143 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 1144 perror("listen"); 1145 cleanup_exit(1); 1146 } 1147 1148 /* 1149 * Fork, and have the parent execute the command, if any, or present 1150 * the socket data. The child continues as the authentication agent. 1151 */ 1152 if (d_flag) { 1153 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1); 1154 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1155 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1156 SSH_AUTHSOCKET_ENV_NAME); 1157 printf("echo Agent pid %ld;\n", (long)parent_pid); 1158 goto skip; 1159 } 1160 pid = fork(); 1161 if (pid == -1) { 1162 perror("fork"); 1163 cleanup_exit(1); 1164 } 1165 if (pid != 0) { /* Parent - execute the given command. */ 1166 close(sock); 1167 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1168 if (ac == 0) { 1169 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1170 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1171 SSH_AUTHSOCKET_ENV_NAME); 1172 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 1173 SSH_AGENTPID_ENV_NAME); 1174 printf("echo Agent pid %ld;\n", (long)pid); 1175 exit(0); 1176 } 1177 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1178 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1179 perror("setenv"); 1180 exit(1); 1181 } 1182 execvp(av[0], av); 1183 perror(av[0]); 1184 exit(1); 1185 } 1186 /* child */ 1187 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1188 1189 if (setsid() == -1) { 1190 error("setsid: %s", strerror(errno)); 1191 cleanup_exit(1); 1192 } 1193 1194 (void)chdir("/"); 1195 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1196 /* XXX might close listen socket */ 1197 (void)dup2(fd, STDIN_FILENO); 1198 (void)dup2(fd, STDOUT_FILENO); 1199 (void)dup2(fd, STDERR_FILENO); 1200 if (fd > 2) 1201 close(fd); 1202 } 1203 1204 #ifdef HAVE_SETRLIMIT 1205 /* deny core dumps, since memory contains unencrypted private keys */ 1206 rlim.rlim_cur = rlim.rlim_max = 0; 1207 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 1208 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1209 cleanup_exit(1); 1210 } 1211 #endif 1212 1213 skip: 1214 new_socket(AUTH_SOCKET, sock); 1215 if (ac > 0) { 1216 mysignal(SIGALRM, check_parent_exists); 1217 alarm(10); 1218 } 1219 idtab_init(); 1220 if (!d_flag) 1221 signal(SIGINT, SIG_IGN); 1222 signal(SIGPIPE, 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); 1229 if (select(max_fd + 1, readsetp, writesetp, NULL, NULL) < 0) { 1230 if (errno == EINTR) 1231 continue; 1232 fatal("select: %s", strerror(errno)); 1233 } 1234 after_select(readsetp, writesetp); 1235 } 1236 /* NOTREACHED */ 1237 } 1238