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 1.108 2003/03/13 11:44:50 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 log("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 log("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; 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 keys = sc_get_keys(sc_reader_id, pin); 592 xfree(sc_reader_id); 593 xfree(pin); 594 595 if (keys == NULL || keys[0] == NULL) { 596 error("sc_get_keys failed"); 597 goto send; 598 } 599 for (i = 0; keys[i] != NULL; i++) { 600 k = keys[i]; 601 version = k->type == KEY_RSA1 ? 1 : 2; 602 tab = idtab_lookup(version); 603 if (lookup_identity(k, version) == NULL) { 604 id = xmalloc(sizeof(Identity)); 605 id->key = k; 606 id->comment = xstrdup("smartcard key"); 607 id->death = 0; 608 id->confirm = 0; 609 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 610 tab->nentries++; 611 success = 1; 612 } else { 613 key_free(k); 614 } 615 keys[i] = NULL; 616 } 617 xfree(keys); 618 send: 619 buffer_put_int(&e->output, 1); 620 buffer_put_char(&e->output, 621 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 622 } 623 624 static void 625 process_remove_smartcard_key(SocketEntry *e) 626 { 627 char *sc_reader_id = NULL, *pin; 628 int i, version, success = 0; 629 Key **keys, *k = NULL; 630 Identity *id; 631 Idtab *tab; 632 633 sc_reader_id = buffer_get_string(&e->request, NULL); 634 pin = buffer_get_string(&e->request, NULL); 635 keys = sc_get_keys(sc_reader_id, pin); 636 xfree(sc_reader_id); 637 xfree(pin); 638 639 if (keys == NULL || keys[0] == NULL) { 640 error("sc_get_keys failed"); 641 goto send; 642 } 643 for (i = 0; keys[i] != NULL; i++) { 644 k = keys[i]; 645 version = k->type == KEY_RSA1 ? 1 : 2; 646 if ((id = lookup_identity(k, version)) != NULL) { 647 tab = idtab_lookup(version); 648 TAILQ_REMOVE(&tab->idlist, id, next); 649 tab->nentries--; 650 free_identity(id); 651 success = 1; 652 } 653 key_free(k); 654 keys[i] = NULL; 655 } 656 xfree(keys); 657 send: 658 buffer_put_int(&e->output, 1); 659 buffer_put_char(&e->output, 660 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 661 } 662 #endif /* SMARTCARD */ 663 664 /* dispatch incoming messages */ 665 666 static void 667 process_message(SocketEntry *e) 668 { 669 u_int msg_len, type; 670 u_char *cp; 671 672 /* kill dead keys */ 673 reaper(); 674 675 if (buffer_len(&e->input) < 5) 676 return; /* Incomplete message. */ 677 cp = buffer_ptr(&e->input); 678 msg_len = GET_32BIT(cp); 679 if (msg_len > 256 * 1024) { 680 close_socket(e); 681 return; 682 } 683 if (buffer_len(&e->input) < msg_len + 4) 684 return; 685 686 /* move the current input to e->request */ 687 buffer_consume(&e->input, 4); 688 buffer_clear(&e->request); 689 buffer_append(&e->request, buffer_ptr(&e->input), msg_len); 690 buffer_consume(&e->input, msg_len); 691 type = buffer_get_char(&e->request); 692 693 /* check wheter agent is locked */ 694 if (locked && type != SSH_AGENTC_UNLOCK) { 695 buffer_clear(&e->request); 696 switch (type) { 697 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 698 case SSH2_AGENTC_REQUEST_IDENTITIES: 699 /* send empty lists */ 700 no_identities(e, type); 701 break; 702 default: 703 /* send a fail message for all other request types */ 704 buffer_put_int(&e->output, 1); 705 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 706 } 707 return; 708 } 709 710 debug("type %d", type); 711 switch (type) { 712 case SSH_AGENTC_LOCK: 713 case SSH_AGENTC_UNLOCK: 714 process_lock_agent(e, type == SSH_AGENTC_LOCK); 715 break; 716 /* ssh1 */ 717 case SSH_AGENTC_RSA_CHALLENGE: 718 process_authentication_challenge1(e); 719 break; 720 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 721 process_request_identities(e, 1); 722 break; 723 case SSH_AGENTC_ADD_RSA_IDENTITY: 724 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 725 process_add_identity(e, 1); 726 break; 727 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 728 process_remove_identity(e, 1); 729 break; 730 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 731 process_remove_all_identities(e, 1); 732 break; 733 /* ssh2 */ 734 case SSH2_AGENTC_SIGN_REQUEST: 735 process_sign_request2(e); 736 break; 737 case SSH2_AGENTC_REQUEST_IDENTITIES: 738 process_request_identities(e, 2); 739 break; 740 case SSH2_AGENTC_ADD_IDENTITY: 741 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 742 process_add_identity(e, 2); 743 break; 744 case SSH2_AGENTC_REMOVE_IDENTITY: 745 process_remove_identity(e, 2); 746 break; 747 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 748 process_remove_all_identities(e, 2); 749 break; 750 #ifdef SMARTCARD 751 case SSH_AGENTC_ADD_SMARTCARD_KEY: 752 process_add_smartcard_key(e); 753 break; 754 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 755 process_remove_smartcard_key(e); 756 break; 757 #endif /* SMARTCARD */ 758 default: 759 /* Unknown message. Respond with failure. */ 760 error("Unknown message %d", type); 761 buffer_clear(&e->request); 762 buffer_put_int(&e->output, 1); 763 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 764 break; 765 } 766 } 767 768 static void 769 new_socket(sock_type type, int fd) 770 { 771 u_int i, old_alloc; 772 773 if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) 774 error("fcntl O_NONBLOCK: %s", strerror(errno)); 775 776 if (fd > max_fd) 777 max_fd = fd; 778 779 for (i = 0; i < sockets_alloc; i++) 780 if (sockets[i].type == AUTH_UNUSED) { 781 sockets[i].fd = fd; 782 sockets[i].type = type; 783 buffer_init(&sockets[i].input); 784 buffer_init(&sockets[i].output); 785 buffer_init(&sockets[i].request); 786 return; 787 } 788 old_alloc = sockets_alloc; 789 sockets_alloc += 10; 790 if (sockets) 791 sockets = xrealloc(sockets, sockets_alloc * sizeof(sockets[0])); 792 else 793 sockets = xmalloc(sockets_alloc * sizeof(sockets[0])); 794 for (i = old_alloc; i < sockets_alloc; i++) 795 sockets[i].type = AUTH_UNUSED; 796 sockets[old_alloc].type = type; 797 sockets[old_alloc].fd = fd; 798 buffer_init(&sockets[old_alloc].input); 799 buffer_init(&sockets[old_alloc].output); 800 buffer_init(&sockets[old_alloc].request); 801 } 802 803 static int 804 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, int *nallocp) 805 { 806 u_int i, sz; 807 int n = 0; 808 809 for (i = 0; i < sockets_alloc; i++) { 810 switch (sockets[i].type) { 811 case AUTH_SOCKET: 812 case AUTH_CONNECTION: 813 n = MAX(n, sockets[i].fd); 814 break; 815 case AUTH_UNUSED: 816 break; 817 default: 818 fatal("Unknown socket type %d", sockets[i].type); 819 break; 820 } 821 } 822 823 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 824 if (*fdrp == NULL || sz > *nallocp) { 825 if (*fdrp) 826 xfree(*fdrp); 827 if (*fdwp) 828 xfree(*fdwp); 829 *fdrp = xmalloc(sz); 830 *fdwp = xmalloc(sz); 831 *nallocp = sz; 832 } 833 if (n < *fdl) 834 debug("XXX shrink: %d < %d", n, *fdl); 835 *fdl = n; 836 memset(*fdrp, 0, sz); 837 memset(*fdwp, 0, sz); 838 839 for (i = 0; i < sockets_alloc; i++) { 840 switch (sockets[i].type) { 841 case AUTH_SOCKET: 842 case AUTH_CONNECTION: 843 FD_SET(sockets[i].fd, *fdrp); 844 if (buffer_len(&sockets[i].output) > 0) 845 FD_SET(sockets[i].fd, *fdwp); 846 break; 847 default: 848 break; 849 } 850 } 851 return (1); 852 } 853 854 static void 855 after_select(fd_set *readset, fd_set *writeset) 856 { 857 struct sockaddr_un sunaddr; 858 socklen_t slen; 859 char buf[1024]; 860 int len, sock; 861 u_int i; 862 uid_t euid; 863 gid_t egid; 864 865 for (i = 0; i < sockets_alloc; i++) 866 switch (sockets[i].type) { 867 case AUTH_UNUSED: 868 break; 869 case AUTH_SOCKET: 870 if (FD_ISSET(sockets[i].fd, readset)) { 871 slen = sizeof(sunaddr); 872 sock = accept(sockets[i].fd, 873 (struct sockaddr *) &sunaddr, &slen); 874 if (sock < 0) { 875 error("accept from AUTH_SOCKET: %s", 876 strerror(errno)); 877 break; 878 } 879 if (getpeereid(sock, &euid, &egid) < 0) { 880 error("getpeereid %d failed: %s", 881 sock, strerror(errno)); 882 close(sock); 883 break; 884 } 885 if ((euid != 0) && (getuid() != euid)) { 886 error("uid mismatch: " 887 "peer euid %u != uid %u", 888 (u_int) euid, (u_int) getuid()); 889 close(sock); 890 break; 891 } 892 new_socket(AUTH_CONNECTION, sock); 893 } 894 break; 895 case AUTH_CONNECTION: 896 if (buffer_len(&sockets[i].output) > 0 && 897 FD_ISSET(sockets[i].fd, writeset)) { 898 do { 899 len = write(sockets[i].fd, 900 buffer_ptr(&sockets[i].output), 901 buffer_len(&sockets[i].output)); 902 if (len == -1 && (errno == EAGAIN || 903 errno == EINTR)) 904 continue; 905 break; 906 } while (1); 907 if (len <= 0) { 908 close_socket(&sockets[i]); 909 break; 910 } 911 buffer_consume(&sockets[i].output, len); 912 } 913 if (FD_ISSET(sockets[i].fd, readset)) { 914 do { 915 len = read(sockets[i].fd, buf, sizeof(buf)); 916 if (len == -1 && (errno == EAGAIN || 917 errno == EINTR)) 918 continue; 919 break; 920 } while (1); 921 if (len <= 0) { 922 close_socket(&sockets[i]); 923 break; 924 } 925 buffer_append(&sockets[i].input, buf, len); 926 process_message(&sockets[i]); 927 } 928 break; 929 default: 930 fatal("Unknown type %d", sockets[i].type); 931 } 932 } 933 934 static void 935 cleanup_socket(void *p) 936 { 937 if (socket_name[0]) 938 unlink(socket_name); 939 if (socket_dir[0]) 940 rmdir(socket_dir); 941 } 942 943 static void 944 cleanup_exit(int i) 945 { 946 cleanup_socket(NULL); 947 exit(i); 948 } 949 950 static void 951 cleanup_handler(int sig) 952 { 953 cleanup_socket(NULL); 954 _exit(2); 955 } 956 957 static void 958 check_parent_exists(int sig) 959 { 960 int save_errno = errno; 961 962 if (parent_pid != -1 && kill(parent_pid, 0) < 0) { 963 /* printf("Parent has died - Authentication agent exiting.\n"); */ 964 cleanup_handler(sig); /* safe */ 965 } 966 signal(SIGALRM, check_parent_exists); 967 alarm(10); 968 errno = save_errno; 969 } 970 971 static void 972 usage(void) 973 { 974 fprintf(stderr, "Usage: %s [options] [command [args ...]]\n", 975 __progname); 976 fprintf(stderr, "Options:\n"); 977 fprintf(stderr, " -c Generate C-shell commands on stdout.\n"); 978 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n"); 979 fprintf(stderr, " -k Kill the current agent.\n"); 980 fprintf(stderr, " -d Debug mode.\n"); 981 fprintf(stderr, " -a socket Bind agent socket to given name.\n"); 982 fprintf(stderr, " -t life Default identity lifetime (seconds).\n"); 983 exit(1); 984 } 985 986 int 987 main(int ac, char **av) 988 { 989 int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0; 990 int sock, fd, ch, nalloc; 991 char *shell, *format, *pidstr, *agentsocket = NULL; 992 fd_set *readsetp = NULL, *writesetp = NULL; 993 struct sockaddr_un sunaddr; 994 #ifdef HAVE_SETRLIMIT 995 struct rlimit rlim; 996 #endif 997 #ifdef HAVE_CYGWIN 998 int prev_mask; 999 #endif 1000 extern int optind; 1001 extern char *optarg; 1002 pid_t pid; 1003 char pidstrbuf[1 + 3 * sizeof pid]; 1004 1005 /* drop */ 1006 setegid(getgid()); 1007 setgid(getgid()); 1008 setuid(geteuid()); 1009 1010 SSLeay_add_all_algorithms(); 1011 1012 __progname = get_progname(av[0]); 1013 init_rng(); 1014 seed_rng(); 1015 1016 while ((ch = getopt(ac, av, "cdksa:t:")) != -1) { 1017 switch (ch) { 1018 case 'c': 1019 if (s_flag) 1020 usage(); 1021 c_flag++; 1022 break; 1023 case 'k': 1024 k_flag++; 1025 break; 1026 case 's': 1027 if (c_flag) 1028 usage(); 1029 s_flag++; 1030 break; 1031 case 'd': 1032 if (d_flag) 1033 usage(); 1034 d_flag++; 1035 break; 1036 case 'a': 1037 agentsocket = optarg; 1038 break; 1039 case 't': 1040 if ((lifetime = convtime(optarg)) == -1) { 1041 fprintf(stderr, "Invalid lifetime\n"); 1042 usage(); 1043 } 1044 break; 1045 default: 1046 usage(); 1047 } 1048 } 1049 ac -= optind; 1050 av += optind; 1051 1052 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag)) 1053 usage(); 1054 1055 if (ac == 0 && !c_flag && !s_flag) { 1056 shell = getenv("SHELL"); 1057 if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0) 1058 c_flag = 1; 1059 } 1060 if (k_flag) { 1061 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1062 if (pidstr == NULL) { 1063 fprintf(stderr, "%s not set, cannot kill agent\n", 1064 SSH_AGENTPID_ENV_NAME); 1065 exit(1); 1066 } 1067 pid = atoi(pidstr); 1068 if (pid < 1) { 1069 fprintf(stderr, "%s=\"%s\", which is not a good PID\n", 1070 SSH_AGENTPID_ENV_NAME, pidstr); 1071 exit(1); 1072 } 1073 if (kill(pid, SIGTERM) == -1) { 1074 perror("kill"); 1075 exit(1); 1076 } 1077 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 1078 printf(format, SSH_AUTHSOCKET_ENV_NAME); 1079 printf(format, SSH_AGENTPID_ENV_NAME); 1080 printf("echo Agent pid %ld killed;\n", (long)pid); 1081 exit(0); 1082 } 1083 parent_pid = getpid(); 1084 1085 if (agentsocket == NULL) { 1086 /* Create private directory for agent socket */ 1087 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXX", sizeof socket_dir); 1088 if (mkdtemp(socket_dir) == NULL) { 1089 perror("mkdtemp: private socket dir"); 1090 exit(1); 1091 } 1092 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1093 (long)parent_pid); 1094 } else { 1095 /* Try to use specified agent socket */ 1096 socket_dir[0] = '\0'; 1097 strlcpy(socket_name, agentsocket, sizeof socket_name); 1098 } 1099 1100 /* 1101 * Create socket early so it will exist before command gets run from 1102 * the parent. 1103 */ 1104 sock = socket(AF_UNIX, SOCK_STREAM, 0); 1105 if (sock < 0) { 1106 perror("socket"); 1107 cleanup_exit(1); 1108 } 1109 memset(&sunaddr, 0, sizeof(sunaddr)); 1110 sunaddr.sun_family = AF_UNIX; 1111 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); 1112 #ifdef HAVE_CYGWIN 1113 prev_mask = umask(0177); 1114 #endif 1115 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) { 1116 perror("bind"); 1117 #ifdef HAVE_CYGWIN 1118 umask(prev_mask); 1119 #endif 1120 cleanup_exit(1); 1121 } 1122 #ifdef HAVE_CYGWIN 1123 umask(prev_mask); 1124 #endif 1125 if (listen(sock, 128) < 0) { 1126 perror("listen"); 1127 cleanup_exit(1); 1128 } 1129 1130 /* 1131 * Fork, and have the parent execute the command, if any, or present 1132 * the socket data. The child continues as the authentication agent. 1133 */ 1134 if (d_flag) { 1135 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1); 1136 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1137 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1138 SSH_AUTHSOCKET_ENV_NAME); 1139 printf("echo Agent pid %ld;\n", (long)parent_pid); 1140 goto skip; 1141 } 1142 pid = fork(); 1143 if (pid == -1) { 1144 perror("fork"); 1145 cleanup_exit(1); 1146 } 1147 if (pid != 0) { /* Parent - execute the given command. */ 1148 close(sock); 1149 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1150 if (ac == 0) { 1151 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1152 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1153 SSH_AUTHSOCKET_ENV_NAME); 1154 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 1155 SSH_AGENTPID_ENV_NAME); 1156 printf("echo Agent pid %ld;\n", (long)pid); 1157 exit(0); 1158 } 1159 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1160 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1161 perror("setenv"); 1162 exit(1); 1163 } 1164 execvp(av[0], av); 1165 perror(av[0]); 1166 exit(1); 1167 } 1168 /* child */ 1169 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1170 1171 if (setsid() == -1) { 1172 error("setsid: %s", strerror(errno)); 1173 cleanup_exit(1); 1174 } 1175 1176 (void)chdir("/"); 1177 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1178 /* XXX might close listen socket */ 1179 (void)dup2(fd, STDIN_FILENO); 1180 (void)dup2(fd, STDOUT_FILENO); 1181 (void)dup2(fd, STDERR_FILENO); 1182 if (fd > 2) 1183 close(fd); 1184 } 1185 1186 #ifdef HAVE_SETRLIMIT 1187 /* deny core dumps, since memory contains unencrypted private keys */ 1188 rlim.rlim_cur = rlim.rlim_max = 0; 1189 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 1190 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1191 cleanup_exit(1); 1192 } 1193 #endif 1194 1195 skip: 1196 fatal_add_cleanup(cleanup_socket, NULL); 1197 new_socket(AUTH_SOCKET, sock); 1198 if (ac > 0) { 1199 signal(SIGALRM, check_parent_exists); 1200 alarm(10); 1201 } 1202 idtab_init(); 1203 if (!d_flag) 1204 signal(SIGINT, SIG_IGN); 1205 signal(SIGPIPE, SIG_IGN); 1206 signal(SIGHUP, cleanup_handler); 1207 signal(SIGTERM, cleanup_handler); 1208 nalloc = 0; 1209 1210 while (1) { 1211 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc); 1212 if (select(max_fd + 1, readsetp, writesetp, NULL, NULL) < 0) { 1213 if (errno == EINTR) 1214 continue; 1215 fatal("select: %s", strerror(errno)); 1216 } 1217 after_select(readsetp, writesetp); 1218 } 1219 /* NOTREACHED */ 1220 } 1221