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/fake-queue.h" 38 RCSID("$OpenBSD: ssh-agent.c,v 1.97 2002/06/24 14:55:38 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 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 } Identity; 82 83 typedef struct { 84 int nentries; 85 TAILQ_HEAD(idqueue, identity) idlist; 86 } Idtab; 87 88 /* private key table, one per protocol version */ 89 Idtab idtable[3]; 90 91 int max_fd = 0; 92 93 /* pid of shell == parent of agent */ 94 pid_t parent_pid = -1; 95 96 /* pathname and directory for AUTH_SOCKET */ 97 char socket_name[1024]; 98 char socket_dir[1024]; 99 100 /* locking */ 101 int locked = 0; 102 char *lock_passwd = NULL; 103 104 #ifdef HAVE___PROGNAME 105 extern char *__progname; 106 #else 107 char *__progname; 108 #endif 109 110 static void 111 idtab_init(void) 112 { 113 int i; 114 115 for (i = 0; i <=2; i++) { 116 TAILQ_INIT(&idtable[i].idlist); 117 idtable[i].nentries = 0; 118 } 119 } 120 121 /* return private key table for requested protocol version */ 122 static Idtab * 123 idtab_lookup(int version) 124 { 125 if (version < 1 || version > 2) 126 fatal("internal error, bad protocol version %d", version); 127 return &idtable[version]; 128 } 129 130 static void 131 free_identity(Identity *id) 132 { 133 key_free(id->key); 134 xfree(id->comment); 135 xfree(id); 136 } 137 138 /* return matching private key for given public key */ 139 static Identity * 140 lookup_identity(Key *key, int version) 141 { 142 Identity *id; 143 144 Idtab *tab = idtab_lookup(version); 145 TAILQ_FOREACH(id, &tab->idlist, next) { 146 if (key_equal(key, id->key)) 147 return (id); 148 } 149 return (NULL); 150 } 151 152 /* send list of supported public keys to 'client' */ 153 static void 154 process_request_identities(SocketEntry *e, int version) 155 { 156 Idtab *tab = idtab_lookup(version); 157 Identity *id; 158 Buffer msg; 159 160 buffer_init(&msg); 161 buffer_put_char(&msg, (version == 1) ? 162 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 163 buffer_put_int(&msg, tab->nentries); 164 TAILQ_FOREACH(id, &tab->idlist, next) { 165 if (id->key->type == KEY_RSA1) { 166 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n)); 167 buffer_put_bignum(&msg, id->key->rsa->e); 168 buffer_put_bignum(&msg, id->key->rsa->n); 169 } else { 170 u_char *blob; 171 u_int blen; 172 key_to_blob(id->key, &blob, &blen); 173 buffer_put_string(&msg, blob, blen); 174 xfree(blob); 175 } 176 buffer_put_cstring(&msg, id->comment); 177 } 178 buffer_put_int(&e->output, buffer_len(&msg)); 179 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 180 buffer_free(&msg); 181 } 182 183 /* ssh1 only */ 184 static void 185 process_authentication_challenge1(SocketEntry *e) 186 { 187 u_char buf[32], mdbuf[16], session_id[16]; 188 u_int response_type; 189 BIGNUM *challenge; 190 Identity *id; 191 int i, len; 192 Buffer msg; 193 MD5_CTX md; 194 Key *key; 195 196 buffer_init(&msg); 197 key = key_new(KEY_RSA1); 198 if ((challenge = BN_new()) == NULL) 199 fatal("process_authentication_challenge1: BN_new failed"); 200 201 (void) buffer_get_int(&e->request); /* ignored */ 202 buffer_get_bignum(&e->request, key->rsa->e); 203 buffer_get_bignum(&e->request, key->rsa->n); 204 buffer_get_bignum(&e->request, challenge); 205 206 /* Only protocol 1.1 is supported */ 207 if (buffer_len(&e->request) == 0) 208 goto failure; 209 buffer_get(&e->request, session_id, 16); 210 response_type = buffer_get_int(&e->request); 211 if (response_type != 1) 212 goto failure; 213 214 id = lookup_identity(key, 1); 215 if (id != NULL) { 216 Key *private = id->key; 217 /* Decrypt the challenge using the private key. */ 218 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0) 219 goto failure; 220 221 /* The response is MD5 of decrypted challenge plus session id. */ 222 len = BN_num_bytes(challenge); 223 if (len <= 0 || len > 32) { 224 log("process_authentication_challenge: bad challenge length %d", len); 225 goto failure; 226 } 227 memset(buf, 0, 32); 228 BN_bn2bin(challenge, buf + 32 - len); 229 MD5_Init(&md); 230 MD5_Update(&md, buf, 32); 231 MD5_Update(&md, session_id, 16); 232 MD5_Final(mdbuf, &md); 233 234 /* Send the response. */ 235 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE); 236 for (i = 0; i < 16; i++) 237 buffer_put_char(&msg, mdbuf[i]); 238 goto send; 239 } 240 241 failure: 242 /* Unknown identity or protocol error. Send failure. */ 243 buffer_put_char(&msg, SSH_AGENT_FAILURE); 244 send: 245 buffer_put_int(&e->output, buffer_len(&msg)); 246 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 247 key_free(key); 248 BN_clear_free(challenge); 249 buffer_free(&msg); 250 } 251 252 /* ssh2 only */ 253 static void 254 process_sign_request2(SocketEntry *e) 255 { 256 u_char *blob, *data, *signature = NULL; 257 u_int blen, dlen, slen = 0; 258 extern int datafellows; 259 int ok = -1, flags; 260 Buffer msg; 261 Key *key; 262 263 datafellows = 0; 264 265 blob = buffer_get_string(&e->request, &blen); 266 data = buffer_get_string(&e->request, &dlen); 267 268 flags = buffer_get_int(&e->request); 269 if (flags & SSH_AGENT_OLD_SIGNATURE) 270 datafellows = SSH_BUG_SIGBLOB; 271 272 key = key_from_blob(blob, blen); 273 if (key != NULL) { 274 Identity *id = lookup_identity(key, 2); 275 if (id != NULL) 276 ok = key_sign(id->key, &signature, &slen, data, dlen); 277 } 278 key_free(key); 279 buffer_init(&msg); 280 if (ok == 0) { 281 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); 282 buffer_put_string(&msg, signature, slen); 283 } else { 284 buffer_put_char(&msg, SSH_AGENT_FAILURE); 285 } 286 buffer_put_int(&e->output, buffer_len(&msg)); 287 buffer_append(&e->output, buffer_ptr(&msg), 288 buffer_len(&msg)); 289 buffer_free(&msg); 290 xfree(data); 291 xfree(blob); 292 if (signature != NULL) 293 xfree(signature); 294 } 295 296 /* shared */ 297 static void 298 process_remove_identity(SocketEntry *e, int version) 299 { 300 u_int blen, bits; 301 int success = 0; 302 Key *key = NULL; 303 u_char *blob; 304 305 switch (version) { 306 case 1: 307 key = key_new(KEY_RSA1); 308 bits = buffer_get_int(&e->request); 309 buffer_get_bignum(&e->request, key->rsa->e); 310 buffer_get_bignum(&e->request, key->rsa->n); 311 312 if (bits != key_size(key)) 313 log("Warning: identity keysize mismatch: actual %u, announced %u", 314 key_size(key), bits); 315 break; 316 case 2: 317 blob = buffer_get_string(&e->request, &blen); 318 key = key_from_blob(blob, blen); 319 xfree(blob); 320 break; 321 } 322 if (key != NULL) { 323 Identity *id = lookup_identity(key, version); 324 if (id != NULL) { 325 /* 326 * We have this key. Free the old key. Since we 327 * don\'t want to leave empty slots in the middle of 328 * the array, we actually free the key there and move 329 * all the entries between the empty slot and the end 330 * of the array. 331 */ 332 Idtab *tab = idtab_lookup(version); 333 if (tab->nentries < 1) 334 fatal("process_remove_identity: " 335 "internal error: tab->nentries %d", 336 tab->nentries); 337 TAILQ_REMOVE(&tab->idlist, id, next); 338 free_identity(id); 339 tab->nentries--; 340 success = 1; 341 } 342 key_free(key); 343 } 344 buffer_put_int(&e->output, 1); 345 buffer_put_char(&e->output, 346 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 347 } 348 349 static void 350 process_remove_all_identities(SocketEntry *e, int version) 351 { 352 Idtab *tab = idtab_lookup(version); 353 Identity *id; 354 355 /* Loop over all identities and clear the keys. */ 356 for (id = TAILQ_FIRST(&tab->idlist); id; 357 id = TAILQ_FIRST(&tab->idlist)) { 358 TAILQ_REMOVE(&tab->idlist, id, next); 359 free_identity(id); 360 } 361 362 /* Mark that there are no identities. */ 363 tab->nentries = 0; 364 365 /* Send success. */ 366 buffer_put_int(&e->output, 1); 367 buffer_put_char(&e->output, SSH_AGENT_SUCCESS); 368 } 369 370 static void 371 reaper(void) 372 { 373 u_int now = time(NULL); 374 Identity *id, *nxt; 375 int version; 376 Idtab *tab; 377 378 for (version = 1; version < 3; version++) { 379 tab = idtab_lookup(version); 380 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 381 nxt = TAILQ_NEXT(id, next); 382 if (id->death != 0 && now >= id->death) { 383 TAILQ_REMOVE(&tab->idlist, id, next); 384 free_identity(id); 385 tab->nentries--; 386 } 387 } 388 } 389 } 390 391 static void 392 process_add_identity(SocketEntry *e, int version) 393 { 394 Idtab *tab = idtab_lookup(version); 395 int type, success = 0, death = 0; 396 char *type_name, *comment; 397 Key *k = NULL; 398 399 switch (version) { 400 case 1: 401 k = key_new_private(KEY_RSA1); 402 (void) buffer_get_int(&e->request); /* ignored */ 403 buffer_get_bignum(&e->request, k->rsa->n); 404 buffer_get_bignum(&e->request, k->rsa->e); 405 buffer_get_bignum(&e->request, k->rsa->d); 406 buffer_get_bignum(&e->request, k->rsa->iqmp); 407 408 /* SSH and SSL have p and q swapped */ 409 buffer_get_bignum(&e->request, k->rsa->q); /* p */ 410 buffer_get_bignum(&e->request, k->rsa->p); /* q */ 411 412 /* Generate additional parameters */ 413 rsa_generate_additional_parameters(k->rsa); 414 break; 415 case 2: 416 type_name = buffer_get_string(&e->request, NULL); 417 type = key_type_from_name(type_name); 418 xfree(type_name); 419 switch (type) { 420 case KEY_DSA: 421 k = key_new_private(type); 422 buffer_get_bignum2(&e->request, k->dsa->p); 423 buffer_get_bignum2(&e->request, k->dsa->q); 424 buffer_get_bignum2(&e->request, k->dsa->g); 425 buffer_get_bignum2(&e->request, k->dsa->pub_key); 426 buffer_get_bignum2(&e->request, k->dsa->priv_key); 427 break; 428 case KEY_RSA: 429 k = key_new_private(type); 430 buffer_get_bignum2(&e->request, k->rsa->n); 431 buffer_get_bignum2(&e->request, k->rsa->e); 432 buffer_get_bignum2(&e->request, k->rsa->d); 433 buffer_get_bignum2(&e->request, k->rsa->iqmp); 434 buffer_get_bignum2(&e->request, k->rsa->p); 435 buffer_get_bignum2(&e->request, k->rsa->q); 436 437 /* Generate additional parameters */ 438 rsa_generate_additional_parameters(k->rsa); 439 break; 440 default: 441 buffer_clear(&e->request); 442 goto send; 443 } 444 break; 445 } 446 comment = buffer_get_string(&e->request, NULL); 447 if (k == NULL) { 448 xfree(comment); 449 goto send; 450 } 451 success = 1; 452 while (buffer_len(&e->request)) { 453 switch (buffer_get_char(&e->request)) { 454 case SSH_AGENT_CONSTRAIN_LIFETIME: 455 death = time(NULL) + buffer_get_int(&e->request); 456 break; 457 default: 458 break; 459 } 460 } 461 if (lookup_identity(k, version) == NULL) { 462 Identity *id = xmalloc(sizeof(Identity)); 463 id->key = k; 464 id->comment = comment; 465 id->death = death; 466 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 467 /* Increment the number of identities. */ 468 tab->nentries++; 469 } else { 470 key_free(k); 471 xfree(comment); 472 } 473 send: 474 buffer_put_int(&e->output, 1); 475 buffer_put_char(&e->output, 476 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 477 } 478 479 /* XXX todo: encrypt sensitive data with passphrase */ 480 static void 481 process_lock_agent(SocketEntry *e, int lock) 482 { 483 int success = 0; 484 char *passwd; 485 486 passwd = buffer_get_string(&e->request, NULL); 487 if (locked && !lock && strcmp(passwd, lock_passwd) == 0) { 488 locked = 0; 489 memset(lock_passwd, 0, strlen(lock_passwd)); 490 xfree(lock_passwd); 491 lock_passwd = NULL; 492 success = 1; 493 } else if (!locked && lock) { 494 locked = 1; 495 lock_passwd = xstrdup(passwd); 496 success = 1; 497 } 498 memset(passwd, 0, strlen(passwd)); 499 xfree(passwd); 500 501 buffer_put_int(&e->output, 1); 502 buffer_put_char(&e->output, 503 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 504 } 505 506 static void 507 no_identities(SocketEntry *e, u_int type) 508 { 509 Buffer msg; 510 511 buffer_init(&msg); 512 buffer_put_char(&msg, 513 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ? 514 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 515 buffer_put_int(&msg, 0); 516 buffer_put_int(&e->output, buffer_len(&msg)); 517 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 518 buffer_free(&msg); 519 } 520 521 #ifdef SMARTCARD 522 static void 523 process_add_smartcard_key (SocketEntry *e) 524 { 525 char *sc_reader_id = NULL, *pin; 526 int i, version, success = 0; 527 Key **keys, *k; 528 Identity *id; 529 Idtab *tab; 530 531 sc_reader_id = buffer_get_string(&e->request, NULL); 532 pin = buffer_get_string(&e->request, NULL); 533 keys = sc_get_keys(sc_reader_id, pin); 534 xfree(sc_reader_id); 535 xfree(pin); 536 537 if (keys == NULL || keys[0] == NULL) { 538 error("sc_get_keys failed"); 539 goto send; 540 } 541 for (i = 0; keys[i] != NULL; i++) { 542 k = keys[i]; 543 version = k->type == KEY_RSA1 ? 1 : 2; 544 tab = idtab_lookup(version); 545 if (lookup_identity(k, version) == NULL) { 546 id = xmalloc(sizeof(Identity)); 547 id->key = k; 548 id->comment = xstrdup("smartcard key"); 549 id->death = 0; 550 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 551 tab->nentries++; 552 success = 1; 553 } else { 554 key_free(k); 555 } 556 keys[i] = NULL; 557 } 558 xfree(keys); 559 send: 560 buffer_put_int(&e->output, 1); 561 buffer_put_char(&e->output, 562 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 563 } 564 565 static void 566 process_remove_smartcard_key(SocketEntry *e) 567 { 568 char *sc_reader_id = NULL, *pin; 569 int i, version, success = 0; 570 Key **keys, *k = NULL; 571 Identity *id; 572 Idtab *tab; 573 574 sc_reader_id = buffer_get_string(&e->request, NULL); 575 pin = buffer_get_string(&e->request, NULL); 576 keys = sc_get_keys(sc_reader_id, pin); 577 xfree(sc_reader_id); 578 xfree(pin); 579 580 if (keys == NULL || keys[0] == NULL) { 581 error("sc_get_keys failed"); 582 goto send; 583 } 584 for (i = 0; keys[i] != NULL; i++) { 585 k = keys[i]; 586 version = k->type == KEY_RSA1 ? 1 : 2; 587 if ((id = lookup_identity(k, version)) != NULL) { 588 tab = idtab_lookup(version); 589 TAILQ_REMOVE(&tab->idlist, id, next); 590 tab->nentries--; 591 free_identity(id); 592 success = 1; 593 } 594 key_free(k); 595 keys[i] = NULL; 596 } 597 xfree(keys); 598 send: 599 buffer_put_int(&e->output, 1); 600 buffer_put_char(&e->output, 601 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 602 } 603 #endif /* SMARTCARD */ 604 605 /* dispatch incoming messages */ 606 607 static void 608 process_message(SocketEntry *e) 609 { 610 u_int msg_len, type; 611 u_char *cp; 612 613 /* kill dead keys */ 614 reaper(); 615 616 if (buffer_len(&e->input) < 5) 617 return; /* Incomplete message. */ 618 cp = buffer_ptr(&e->input); 619 msg_len = GET_32BIT(cp); 620 if (msg_len > 256 * 1024) { 621 shutdown(e->fd, SHUT_RDWR); 622 close(e->fd); 623 e->fd = -1; 624 e->type = AUTH_UNUSED; 625 buffer_free(&e->input); 626 buffer_free(&e->output); 627 buffer_free(&e->request); 628 return; 629 } 630 if (buffer_len(&e->input) < msg_len + 4) 631 return; 632 633 /* move the current input to e->request */ 634 buffer_consume(&e->input, 4); 635 buffer_clear(&e->request); 636 buffer_append(&e->request, buffer_ptr(&e->input), msg_len); 637 buffer_consume(&e->input, msg_len); 638 type = buffer_get_char(&e->request); 639 640 /* check wheter agent is locked */ 641 if (locked && type != SSH_AGENTC_UNLOCK) { 642 buffer_clear(&e->request); 643 switch (type) { 644 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 645 case SSH2_AGENTC_REQUEST_IDENTITIES: 646 /* send empty lists */ 647 no_identities(e, type); 648 break; 649 default: 650 /* send a fail message for all other request types */ 651 buffer_put_int(&e->output, 1); 652 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 653 } 654 return; 655 } 656 657 debug("type %d", type); 658 switch (type) { 659 case SSH_AGENTC_LOCK: 660 case SSH_AGENTC_UNLOCK: 661 process_lock_agent(e, type == SSH_AGENTC_LOCK); 662 break; 663 /* ssh1 */ 664 case SSH_AGENTC_RSA_CHALLENGE: 665 process_authentication_challenge1(e); 666 break; 667 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 668 process_request_identities(e, 1); 669 break; 670 case SSH_AGENTC_ADD_RSA_IDENTITY: 671 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 672 process_add_identity(e, 1); 673 break; 674 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 675 process_remove_identity(e, 1); 676 break; 677 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 678 process_remove_all_identities(e, 1); 679 break; 680 /* ssh2 */ 681 case SSH2_AGENTC_SIGN_REQUEST: 682 process_sign_request2(e); 683 break; 684 case SSH2_AGENTC_REQUEST_IDENTITIES: 685 process_request_identities(e, 2); 686 break; 687 case SSH2_AGENTC_ADD_IDENTITY: 688 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 689 process_add_identity(e, 2); 690 break; 691 case SSH2_AGENTC_REMOVE_IDENTITY: 692 process_remove_identity(e, 2); 693 break; 694 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 695 process_remove_all_identities(e, 2); 696 break; 697 #ifdef SMARTCARD 698 case SSH_AGENTC_ADD_SMARTCARD_KEY: 699 process_add_smartcard_key(e); 700 break; 701 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 702 process_remove_smartcard_key(e); 703 break; 704 #endif /* SMARTCARD */ 705 default: 706 /* Unknown message. Respond with failure. */ 707 error("Unknown message %d", type); 708 buffer_clear(&e->request); 709 buffer_put_int(&e->output, 1); 710 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 711 break; 712 } 713 } 714 715 static void 716 new_socket(sock_type type, int fd) 717 { 718 u_int i, old_alloc; 719 720 if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) 721 error("fcntl O_NONBLOCK: %s", strerror(errno)); 722 723 if (fd > max_fd) 724 max_fd = fd; 725 726 for (i = 0; i < sockets_alloc; i++) 727 if (sockets[i].type == AUTH_UNUSED) { 728 sockets[i].fd = fd; 729 sockets[i].type = type; 730 buffer_init(&sockets[i].input); 731 buffer_init(&sockets[i].output); 732 buffer_init(&sockets[i].request); 733 return; 734 } 735 old_alloc = sockets_alloc; 736 sockets_alloc += 10; 737 if (sockets) 738 sockets = xrealloc(sockets, sockets_alloc * sizeof(sockets[0])); 739 else 740 sockets = xmalloc(sockets_alloc * sizeof(sockets[0])); 741 for (i = old_alloc; i < sockets_alloc; i++) 742 sockets[i].type = AUTH_UNUSED; 743 sockets[old_alloc].type = type; 744 sockets[old_alloc].fd = fd; 745 buffer_init(&sockets[old_alloc].input); 746 buffer_init(&sockets[old_alloc].output); 747 buffer_init(&sockets[old_alloc].request); 748 } 749 750 static int 751 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, int *nallocp) 752 { 753 u_int i, sz; 754 int n = 0; 755 756 for (i = 0; i < sockets_alloc; i++) { 757 switch (sockets[i].type) { 758 case AUTH_SOCKET: 759 case AUTH_CONNECTION: 760 n = MAX(n, sockets[i].fd); 761 break; 762 case AUTH_UNUSED: 763 break; 764 default: 765 fatal("Unknown socket type %d", sockets[i].type); 766 break; 767 } 768 } 769 770 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 771 if (*fdrp == NULL || sz > *nallocp) { 772 if (*fdrp) 773 xfree(*fdrp); 774 if (*fdwp) 775 xfree(*fdwp); 776 *fdrp = xmalloc(sz); 777 *fdwp = xmalloc(sz); 778 *nallocp = sz; 779 } 780 if (n < *fdl) 781 debug("XXX shrink: %d < %d", n, *fdl); 782 *fdl = n; 783 memset(*fdrp, 0, sz); 784 memset(*fdwp, 0, sz); 785 786 for (i = 0; i < sockets_alloc; i++) { 787 switch (sockets[i].type) { 788 case AUTH_SOCKET: 789 case AUTH_CONNECTION: 790 FD_SET(sockets[i].fd, *fdrp); 791 if (buffer_len(&sockets[i].output) > 0) 792 FD_SET(sockets[i].fd, *fdwp); 793 break; 794 default: 795 break; 796 } 797 } 798 return (1); 799 } 800 801 static void 802 after_select(fd_set *readset, fd_set *writeset) 803 { 804 struct sockaddr_un sunaddr; 805 socklen_t slen; 806 char buf[1024]; 807 int len, sock; 808 u_int i; 809 810 for (i = 0; i < sockets_alloc; i++) 811 switch (sockets[i].type) { 812 case AUTH_UNUSED: 813 break; 814 case AUTH_SOCKET: 815 if (FD_ISSET(sockets[i].fd, readset)) { 816 slen = sizeof(sunaddr); 817 sock = accept(sockets[i].fd, 818 (struct sockaddr *) &sunaddr, &slen); 819 if (sock < 0) { 820 error("accept from AUTH_SOCKET: %s", 821 strerror(errno)); 822 break; 823 } 824 new_socket(AUTH_CONNECTION, sock); 825 } 826 break; 827 case AUTH_CONNECTION: 828 if (buffer_len(&sockets[i].output) > 0 && 829 FD_ISSET(sockets[i].fd, writeset)) { 830 do { 831 len = write(sockets[i].fd, 832 buffer_ptr(&sockets[i].output), 833 buffer_len(&sockets[i].output)); 834 if (len == -1 && (errno == EAGAIN || 835 errno == EINTR)) 836 continue; 837 break; 838 } while (1); 839 if (len <= 0) { 840 shutdown(sockets[i].fd, SHUT_RDWR); 841 close(sockets[i].fd); 842 sockets[i].fd = -1; 843 sockets[i].type = AUTH_UNUSED; 844 buffer_free(&sockets[i].input); 845 buffer_free(&sockets[i].output); 846 buffer_free(&sockets[i].request); 847 break; 848 } 849 buffer_consume(&sockets[i].output, len); 850 } 851 if (FD_ISSET(sockets[i].fd, readset)) { 852 do { 853 len = read(sockets[i].fd, buf, sizeof(buf)); 854 if (len == -1 && (errno == EAGAIN || 855 errno == EINTR)) 856 continue; 857 break; 858 } while (1); 859 if (len <= 0) { 860 shutdown(sockets[i].fd, SHUT_RDWR); 861 close(sockets[i].fd); 862 sockets[i].fd = -1; 863 sockets[i].type = AUTH_UNUSED; 864 buffer_free(&sockets[i].input); 865 buffer_free(&sockets[i].output); 866 buffer_free(&sockets[i].request); 867 break; 868 } 869 buffer_append(&sockets[i].input, buf, len); 870 process_message(&sockets[i]); 871 } 872 break; 873 default: 874 fatal("Unknown type %d", sockets[i].type); 875 } 876 } 877 878 static void 879 cleanup_socket(void *p) 880 { 881 if (socket_name[0]) 882 unlink(socket_name); 883 if (socket_dir[0]) 884 rmdir(socket_dir); 885 } 886 887 static void 888 cleanup_exit(int i) 889 { 890 cleanup_socket(NULL); 891 exit(i); 892 } 893 894 static void 895 cleanup_handler(int sig) 896 { 897 cleanup_socket(NULL); 898 _exit(2); 899 } 900 901 static void 902 check_parent_exists(int sig) 903 { 904 int save_errno = errno; 905 906 if (parent_pid != -1 && kill(parent_pid, 0) < 0) { 907 /* printf("Parent has died - Authentication agent exiting.\n"); */ 908 cleanup_handler(sig); /* safe */ 909 } 910 signal(SIGALRM, check_parent_exists); 911 alarm(10); 912 errno = save_errno; 913 } 914 915 static void 916 usage(void) 917 { 918 fprintf(stderr, "Usage: %s [options] [command [args ...]]\n", 919 __progname); 920 fprintf(stderr, "Options:\n"); 921 fprintf(stderr, " -c Generate C-shell commands on stdout.\n"); 922 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n"); 923 fprintf(stderr, " -k Kill the current agent.\n"); 924 fprintf(stderr, " -d Debug mode.\n"); 925 fprintf(stderr, " -a socket Bind agent socket to given name.\n"); 926 exit(1); 927 } 928 929 int 930 main(int ac, char **av) 931 { 932 int sock, c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0, ch, nalloc; 933 char *shell, *format, *pidstr, *agentsocket = NULL; 934 fd_set *readsetp = NULL, *writesetp = NULL; 935 struct sockaddr_un sunaddr; 936 #ifdef HAVE_SETRLIMIT 937 struct rlimit rlim; 938 #endif 939 #ifdef HAVE_CYGWIN 940 int prev_mask; 941 #endif 942 extern int optind; 943 extern char *optarg; 944 pid_t pid; 945 char pidstrbuf[1 + 3 * sizeof pid]; 946 947 SSLeay_add_all_algorithms(); 948 949 __progname = get_progname(av[0]); 950 init_rng(); 951 seed_rng(); 952 953 while ((ch = getopt(ac, av, "cdksa:")) != -1) { 954 switch (ch) { 955 case 'c': 956 if (s_flag) 957 usage(); 958 c_flag++; 959 break; 960 case 'k': 961 k_flag++; 962 break; 963 case 's': 964 if (c_flag) 965 usage(); 966 s_flag++; 967 break; 968 case 'd': 969 if (d_flag) 970 usage(); 971 d_flag++; 972 break; 973 case 'a': 974 agentsocket = optarg; 975 break; 976 default: 977 usage(); 978 } 979 } 980 ac -= optind; 981 av += optind; 982 983 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag)) 984 usage(); 985 986 if (ac == 0 && !c_flag && !s_flag) { 987 shell = getenv("SHELL"); 988 if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0) 989 c_flag = 1; 990 } 991 if (k_flag) { 992 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 993 if (pidstr == NULL) { 994 fprintf(stderr, "%s not set, cannot kill agent\n", 995 SSH_AGENTPID_ENV_NAME); 996 exit(1); 997 } 998 pid = atoi(pidstr); 999 if (pid < 1) { 1000 fprintf(stderr, "%s=\"%s\", which is not a good PID\n", 1001 SSH_AGENTPID_ENV_NAME, pidstr); 1002 exit(1); 1003 } 1004 if (kill(pid, SIGTERM) == -1) { 1005 perror("kill"); 1006 exit(1); 1007 } 1008 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 1009 printf(format, SSH_AUTHSOCKET_ENV_NAME); 1010 printf(format, SSH_AGENTPID_ENV_NAME); 1011 printf("echo Agent pid %ld killed;\n", (long)pid); 1012 exit(0); 1013 } 1014 parent_pid = getpid(); 1015 1016 if (agentsocket == NULL) { 1017 /* Create private directory for agent socket */ 1018 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXX", sizeof socket_dir); 1019 if (mkdtemp(socket_dir) == NULL) { 1020 perror("mkdtemp: private socket dir"); 1021 exit(1); 1022 } 1023 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1024 (long)parent_pid); 1025 } else { 1026 /* Try to use specified agent socket */ 1027 socket_dir[0] = '\0'; 1028 strlcpy(socket_name, agentsocket, sizeof socket_name); 1029 } 1030 1031 /* 1032 * Create socket early so it will exist before command gets run from 1033 * the parent. 1034 */ 1035 sock = socket(AF_UNIX, SOCK_STREAM, 0); 1036 if (sock < 0) { 1037 perror("socket"); 1038 cleanup_exit(1); 1039 } 1040 memset(&sunaddr, 0, sizeof(sunaddr)); 1041 sunaddr.sun_family = AF_UNIX; 1042 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); 1043 #ifdef HAVE_CYGWIN 1044 prev_mask = umask(0177); 1045 #endif 1046 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) { 1047 perror("bind"); 1048 #ifdef HAVE_CYGWIN 1049 umask(prev_mask); 1050 #endif 1051 cleanup_exit(1); 1052 } 1053 #ifdef HAVE_CYGWIN 1054 umask(prev_mask); 1055 #endif 1056 if (listen(sock, 5) < 0) { 1057 perror("listen"); 1058 cleanup_exit(1); 1059 } 1060 1061 /* 1062 * Fork, and have the parent execute the command, if any, or present 1063 * the socket data. The child continues as the authentication agent. 1064 */ 1065 if (d_flag) { 1066 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1); 1067 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1068 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1069 SSH_AUTHSOCKET_ENV_NAME); 1070 printf("echo Agent pid %ld;\n", (long)parent_pid); 1071 goto skip; 1072 } 1073 pid = fork(); 1074 if (pid == -1) { 1075 perror("fork"); 1076 cleanup_exit(1); 1077 } 1078 if (pid != 0) { /* Parent - execute the given command. */ 1079 close(sock); 1080 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1081 if (ac == 0) { 1082 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1083 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1084 SSH_AUTHSOCKET_ENV_NAME); 1085 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 1086 SSH_AGENTPID_ENV_NAME); 1087 printf("echo Agent pid %ld;\n", (long)pid); 1088 exit(0); 1089 } 1090 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1091 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1092 perror("setenv"); 1093 exit(1); 1094 } 1095 execvp(av[0], av); 1096 perror(av[0]); 1097 exit(1); 1098 } 1099 /* child */ 1100 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1101 1102 if (setsid() == -1) { 1103 error("setsid: %s", strerror(errno)); 1104 cleanup_exit(1); 1105 } 1106 1107 (void)chdir("/"); 1108 close(0); 1109 close(1); 1110 close(2); 1111 1112 #ifdef HAVE_SETRLIMIT 1113 /* deny core dumps, since memory contains unencrypted private keys */ 1114 rlim.rlim_cur = rlim.rlim_max = 0; 1115 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 1116 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1117 cleanup_exit(1); 1118 } 1119 #endif 1120 1121 skip: 1122 fatal_add_cleanup(cleanup_socket, NULL); 1123 new_socket(AUTH_SOCKET, sock); 1124 if (ac > 0) { 1125 signal(SIGALRM, check_parent_exists); 1126 alarm(10); 1127 } 1128 idtab_init(); 1129 if (!d_flag) 1130 signal(SIGINT, SIG_IGN); 1131 signal(SIGPIPE, SIG_IGN); 1132 signal(SIGHUP, cleanup_handler); 1133 signal(SIGTERM, cleanup_handler); 1134 nalloc = 0; 1135 1136 while (1) { 1137 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc); 1138 if (select(max_fd + 1, readsetp, writesetp, NULL, NULL) < 0) { 1139 if (errno == EINTR) 1140 continue; 1141 fatal("select: %s", strerror(errno)); 1142 } 1143 after_select(readsetp, writesetp); 1144 } 1145 /* NOTREACHED */ 1146 } 1147