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 1.105 2002/10/01 20:34:12 markus Exp $"); 39 RCSID("$FreeBSD: src/crypto/openssh/ssh-agent.c,v 1.2.2.10 2003/02/11 08:27:40 des Exp $"); 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 close_socket(SocketEntry *e) 112 { 113 close(e->fd); 114 e->fd = -1; 115 e->type = AUTH_UNUSED; 116 buffer_free(&e->input); 117 buffer_free(&e->output); 118 buffer_free(&e->request); 119 } 120 121 static void 122 idtab_init(void) 123 { 124 int i; 125 126 for (i = 0; i <=2; i++) { 127 TAILQ_INIT(&idtable[i].idlist); 128 idtable[i].nentries = 0; 129 } 130 } 131 132 /* return private key table for requested protocol version */ 133 static Idtab * 134 idtab_lookup(int version) 135 { 136 if (version < 1 || version > 2) 137 fatal("internal error, bad protocol version %d", version); 138 return &idtable[version]; 139 } 140 141 static void 142 free_identity(Identity *id) 143 { 144 key_free(id->key); 145 xfree(id->comment); 146 xfree(id); 147 } 148 149 /* return matching private key for given public key */ 150 static Identity * 151 lookup_identity(Key *key, int version) 152 { 153 Identity *id; 154 155 Idtab *tab = idtab_lookup(version); 156 TAILQ_FOREACH(id, &tab->idlist, next) { 157 if (key_equal(key, id->key)) 158 return (id); 159 } 160 return (NULL); 161 } 162 163 /* send list of supported public keys to 'client' */ 164 static void 165 process_request_identities(SocketEntry *e, int version) 166 { 167 Idtab *tab = idtab_lookup(version); 168 Identity *id; 169 Buffer msg; 170 171 buffer_init(&msg); 172 buffer_put_char(&msg, (version == 1) ? 173 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 174 buffer_put_int(&msg, tab->nentries); 175 TAILQ_FOREACH(id, &tab->idlist, next) { 176 if (id->key->type == KEY_RSA1) { 177 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n)); 178 buffer_put_bignum(&msg, id->key->rsa->e); 179 buffer_put_bignum(&msg, id->key->rsa->n); 180 } else { 181 u_char *blob; 182 u_int blen; 183 key_to_blob(id->key, &blob, &blen); 184 buffer_put_string(&msg, blob, blen); 185 xfree(blob); 186 } 187 buffer_put_cstring(&msg, id->comment); 188 } 189 buffer_put_int(&e->output, buffer_len(&msg)); 190 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 191 buffer_free(&msg); 192 } 193 194 /* ssh1 only */ 195 static void 196 process_authentication_challenge1(SocketEntry *e) 197 { 198 u_char buf[32], mdbuf[16], session_id[16]; 199 u_int response_type; 200 BIGNUM *challenge; 201 Identity *id; 202 int i, len; 203 Buffer msg; 204 MD5_CTX md; 205 Key *key; 206 207 buffer_init(&msg); 208 key = key_new(KEY_RSA1); 209 if ((challenge = BN_new()) == NULL) 210 fatal("process_authentication_challenge1: BN_new failed"); 211 212 (void) buffer_get_int(&e->request); /* ignored */ 213 buffer_get_bignum(&e->request, key->rsa->e); 214 buffer_get_bignum(&e->request, key->rsa->n); 215 buffer_get_bignum(&e->request, challenge); 216 217 /* Only protocol 1.1 is supported */ 218 if (buffer_len(&e->request) == 0) 219 goto failure; 220 buffer_get(&e->request, session_id, 16); 221 response_type = buffer_get_int(&e->request); 222 if (response_type != 1) 223 goto failure; 224 225 id = lookup_identity(key, 1); 226 if (id != NULL) { 227 Key *private = id->key; 228 /* Decrypt the challenge using the private key. */ 229 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0) 230 goto failure; 231 232 /* The response is MD5 of decrypted challenge plus session id. */ 233 len = BN_num_bytes(challenge); 234 if (len <= 0 || len > 32) { 235 log("process_authentication_challenge: bad challenge length %d", len); 236 goto failure; 237 } 238 memset(buf, 0, 32); 239 BN_bn2bin(challenge, buf + 32 - len); 240 MD5_Init(&md); 241 MD5_Update(&md, buf, 32); 242 MD5_Update(&md, session_id, 16); 243 MD5_Final(mdbuf, &md); 244 245 /* Send the response. */ 246 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE); 247 for (i = 0; i < 16; i++) 248 buffer_put_char(&msg, mdbuf[i]); 249 goto send; 250 } 251 252 failure: 253 /* Unknown identity or protocol error. Send failure. */ 254 buffer_put_char(&msg, SSH_AGENT_FAILURE); 255 send: 256 buffer_put_int(&e->output, buffer_len(&msg)); 257 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 258 key_free(key); 259 BN_clear_free(challenge); 260 buffer_free(&msg); 261 } 262 263 /* ssh2 only */ 264 static void 265 process_sign_request2(SocketEntry *e) 266 { 267 u_char *blob, *data, *signature = NULL; 268 u_int blen, dlen, slen = 0; 269 extern int datafellows; 270 int ok = -1, flags; 271 Buffer msg; 272 Key *key; 273 274 datafellows = 0; 275 276 blob = buffer_get_string(&e->request, &blen); 277 data = buffer_get_string(&e->request, &dlen); 278 279 flags = buffer_get_int(&e->request); 280 if (flags & SSH_AGENT_OLD_SIGNATURE) 281 datafellows = SSH_BUG_SIGBLOB; 282 283 key = key_from_blob(blob, blen); 284 if (key != NULL) { 285 Identity *id = lookup_identity(key, 2); 286 if (id != NULL) 287 ok = key_sign(id->key, &signature, &slen, data, dlen); 288 } 289 key_free(key); 290 buffer_init(&msg); 291 if (ok == 0) { 292 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); 293 buffer_put_string(&msg, signature, slen); 294 } else { 295 buffer_put_char(&msg, SSH_AGENT_FAILURE); 296 } 297 buffer_put_int(&e->output, buffer_len(&msg)); 298 buffer_append(&e->output, buffer_ptr(&msg), 299 buffer_len(&msg)); 300 buffer_free(&msg); 301 xfree(data); 302 xfree(blob); 303 if (signature != NULL) 304 xfree(signature); 305 } 306 307 /* shared */ 308 static void 309 process_remove_identity(SocketEntry *e, int version) 310 { 311 u_int blen, bits; 312 int success = 0; 313 Key *key = NULL; 314 u_char *blob; 315 316 switch (version) { 317 case 1: 318 key = key_new(KEY_RSA1); 319 bits = buffer_get_int(&e->request); 320 buffer_get_bignum(&e->request, key->rsa->e); 321 buffer_get_bignum(&e->request, key->rsa->n); 322 323 if (bits != key_size(key)) 324 log("Warning: identity keysize mismatch: actual %u, announced %u", 325 key_size(key), bits); 326 break; 327 case 2: 328 blob = buffer_get_string(&e->request, &blen); 329 key = key_from_blob(blob, blen); 330 xfree(blob); 331 break; 332 } 333 if (key != NULL) { 334 Identity *id = lookup_identity(key, version); 335 if (id != NULL) { 336 /* 337 * We have this key. Free the old key. Since we 338 * don\'t want to leave empty slots in the middle of 339 * the array, we actually free the key there and move 340 * all the entries between the empty slot and the end 341 * of the array. 342 */ 343 Idtab *tab = idtab_lookup(version); 344 if (tab->nentries < 1) 345 fatal("process_remove_identity: " 346 "internal error: tab->nentries %d", 347 tab->nentries); 348 TAILQ_REMOVE(&tab->idlist, id, next); 349 free_identity(id); 350 tab->nentries--; 351 success = 1; 352 } 353 key_free(key); 354 } 355 buffer_put_int(&e->output, 1); 356 buffer_put_char(&e->output, 357 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 358 } 359 360 static void 361 process_remove_all_identities(SocketEntry *e, int version) 362 { 363 Idtab *tab = idtab_lookup(version); 364 Identity *id; 365 366 /* Loop over all identities and clear the keys. */ 367 for (id = TAILQ_FIRST(&tab->idlist); id; 368 id = TAILQ_FIRST(&tab->idlist)) { 369 TAILQ_REMOVE(&tab->idlist, id, next); 370 free_identity(id); 371 } 372 373 /* Mark that there are no identities. */ 374 tab->nentries = 0; 375 376 /* Send success. */ 377 buffer_put_int(&e->output, 1); 378 buffer_put_char(&e->output, SSH_AGENT_SUCCESS); 379 } 380 381 static void 382 reaper(void) 383 { 384 u_int now = time(NULL); 385 Identity *id, *nxt; 386 int version; 387 Idtab *tab; 388 389 for (version = 1; version < 3; version++) { 390 tab = idtab_lookup(version); 391 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 392 nxt = TAILQ_NEXT(id, next); 393 if (id->death != 0 && now >= id->death) { 394 TAILQ_REMOVE(&tab->idlist, id, next); 395 free_identity(id); 396 tab->nentries--; 397 } 398 } 399 } 400 } 401 402 static void 403 process_add_identity(SocketEntry *e, int version) 404 { 405 Idtab *tab = idtab_lookup(version); 406 int type, success = 0, death = 0; 407 char *type_name, *comment; 408 Key *k = NULL; 409 410 switch (version) { 411 case 1: 412 k = key_new_private(KEY_RSA1); 413 (void) buffer_get_int(&e->request); /* ignored */ 414 buffer_get_bignum(&e->request, k->rsa->n); 415 buffer_get_bignum(&e->request, k->rsa->e); 416 buffer_get_bignum(&e->request, k->rsa->d); 417 buffer_get_bignum(&e->request, k->rsa->iqmp); 418 419 /* SSH and SSL have p and q swapped */ 420 buffer_get_bignum(&e->request, k->rsa->q); /* p */ 421 buffer_get_bignum(&e->request, k->rsa->p); /* q */ 422 423 /* Generate additional parameters */ 424 rsa_generate_additional_parameters(k->rsa); 425 break; 426 case 2: 427 type_name = buffer_get_string(&e->request, NULL); 428 type = key_type_from_name(type_name); 429 xfree(type_name); 430 switch (type) { 431 case KEY_DSA: 432 k = key_new_private(type); 433 buffer_get_bignum2(&e->request, k->dsa->p); 434 buffer_get_bignum2(&e->request, k->dsa->q); 435 buffer_get_bignum2(&e->request, k->dsa->g); 436 buffer_get_bignum2(&e->request, k->dsa->pub_key); 437 buffer_get_bignum2(&e->request, k->dsa->priv_key); 438 break; 439 case KEY_RSA: 440 k = key_new_private(type); 441 buffer_get_bignum2(&e->request, k->rsa->n); 442 buffer_get_bignum2(&e->request, k->rsa->e); 443 buffer_get_bignum2(&e->request, k->rsa->d); 444 buffer_get_bignum2(&e->request, k->rsa->iqmp); 445 buffer_get_bignum2(&e->request, k->rsa->p); 446 buffer_get_bignum2(&e->request, k->rsa->q); 447 448 /* Generate additional parameters */ 449 rsa_generate_additional_parameters(k->rsa); 450 break; 451 default: 452 buffer_clear(&e->request); 453 goto send; 454 } 455 break; 456 } 457 comment = buffer_get_string(&e->request, NULL); 458 if (k == NULL) { 459 xfree(comment); 460 goto send; 461 } 462 success = 1; 463 while (buffer_len(&e->request)) { 464 switch (buffer_get_char(&e->request)) { 465 case SSH_AGENT_CONSTRAIN_LIFETIME: 466 death = time(NULL) + buffer_get_int(&e->request); 467 break; 468 default: 469 break; 470 } 471 } 472 if (lookup_identity(k, version) == NULL) { 473 Identity *id = xmalloc(sizeof(Identity)); 474 id->key = k; 475 id->comment = comment; 476 id->death = death; 477 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 478 /* Increment the number of identities. */ 479 tab->nentries++; 480 } else { 481 key_free(k); 482 xfree(comment); 483 } 484 send: 485 buffer_put_int(&e->output, 1); 486 buffer_put_char(&e->output, 487 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 488 } 489 490 /* XXX todo: encrypt sensitive data with passphrase */ 491 static void 492 process_lock_agent(SocketEntry *e, int lock) 493 { 494 int success = 0; 495 char *passwd; 496 497 passwd = buffer_get_string(&e->request, NULL); 498 if (locked && !lock && strcmp(passwd, lock_passwd) == 0) { 499 locked = 0; 500 memset(lock_passwd, 0, strlen(lock_passwd)); 501 xfree(lock_passwd); 502 lock_passwd = NULL; 503 success = 1; 504 } else if (!locked && lock) { 505 locked = 1; 506 lock_passwd = xstrdup(passwd); 507 success = 1; 508 } 509 memset(passwd, 0, strlen(passwd)); 510 xfree(passwd); 511 512 buffer_put_int(&e->output, 1); 513 buffer_put_char(&e->output, 514 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 515 } 516 517 static void 518 no_identities(SocketEntry *e, u_int type) 519 { 520 Buffer msg; 521 522 buffer_init(&msg); 523 buffer_put_char(&msg, 524 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ? 525 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 526 buffer_put_int(&msg, 0); 527 buffer_put_int(&e->output, buffer_len(&msg)); 528 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 529 buffer_free(&msg); 530 } 531 532 #ifdef SMARTCARD 533 static void 534 process_add_smartcard_key (SocketEntry *e) 535 { 536 char *sc_reader_id = NULL, *pin; 537 int i, version, success = 0; 538 Key **keys, *k; 539 Identity *id; 540 Idtab *tab; 541 542 sc_reader_id = buffer_get_string(&e->request, NULL); 543 pin = buffer_get_string(&e->request, NULL); 544 keys = sc_get_keys(sc_reader_id, pin); 545 xfree(sc_reader_id); 546 xfree(pin); 547 548 if (keys == NULL || keys[0] == NULL) { 549 error("sc_get_keys failed"); 550 goto send; 551 } 552 for (i = 0; keys[i] != NULL; i++) { 553 k = keys[i]; 554 version = k->type == KEY_RSA1 ? 1 : 2; 555 tab = idtab_lookup(version); 556 if (lookup_identity(k, version) == NULL) { 557 id = xmalloc(sizeof(Identity)); 558 id->key = k; 559 id->comment = xstrdup("smartcard key"); 560 id->death = 0; 561 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 562 tab->nentries++; 563 success = 1; 564 } else { 565 key_free(k); 566 } 567 keys[i] = NULL; 568 } 569 xfree(keys); 570 send: 571 buffer_put_int(&e->output, 1); 572 buffer_put_char(&e->output, 573 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 574 } 575 576 static void 577 process_remove_smartcard_key(SocketEntry *e) 578 { 579 char *sc_reader_id = NULL, *pin; 580 int i, version, success = 0; 581 Key **keys, *k = NULL; 582 Identity *id; 583 Idtab *tab; 584 585 sc_reader_id = buffer_get_string(&e->request, NULL); 586 pin = buffer_get_string(&e->request, NULL); 587 keys = sc_get_keys(sc_reader_id, pin); 588 xfree(sc_reader_id); 589 xfree(pin); 590 591 if (keys == NULL || keys[0] == NULL) { 592 error("sc_get_keys failed"); 593 goto send; 594 } 595 for (i = 0; keys[i] != NULL; i++) { 596 k = keys[i]; 597 version = k->type == KEY_RSA1 ? 1 : 2; 598 if ((id = lookup_identity(k, version)) != NULL) { 599 tab = idtab_lookup(version); 600 TAILQ_REMOVE(&tab->idlist, id, next); 601 tab->nentries--; 602 free_identity(id); 603 success = 1; 604 } 605 key_free(k); 606 keys[i] = NULL; 607 } 608 xfree(keys); 609 send: 610 buffer_put_int(&e->output, 1); 611 buffer_put_char(&e->output, 612 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 613 } 614 #endif /* SMARTCARD */ 615 616 /* dispatch incoming messages */ 617 618 static void 619 process_message(SocketEntry *e) 620 { 621 u_int msg_len, type; 622 u_char *cp; 623 624 /* kill dead keys */ 625 reaper(); 626 627 if (buffer_len(&e->input) < 5) 628 return; /* Incomplete message. */ 629 cp = buffer_ptr(&e->input); 630 msg_len = GET_32BIT(cp); 631 if (msg_len > 256 * 1024) { 632 close_socket(e); 633 return; 634 } 635 if (buffer_len(&e->input) < msg_len + 4) 636 return; 637 638 /* move the current input to e->request */ 639 buffer_consume(&e->input, 4); 640 buffer_clear(&e->request); 641 buffer_append(&e->request, buffer_ptr(&e->input), msg_len); 642 buffer_consume(&e->input, msg_len); 643 type = buffer_get_char(&e->request); 644 645 /* check wheter agent is locked */ 646 if (locked && type != SSH_AGENTC_UNLOCK) { 647 buffer_clear(&e->request); 648 switch (type) { 649 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 650 case SSH2_AGENTC_REQUEST_IDENTITIES: 651 /* send empty lists */ 652 no_identities(e, type); 653 break; 654 default: 655 /* send a fail message for all other request types */ 656 buffer_put_int(&e->output, 1); 657 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 658 } 659 return; 660 } 661 662 debug("type %d", type); 663 switch (type) { 664 case SSH_AGENTC_LOCK: 665 case SSH_AGENTC_UNLOCK: 666 process_lock_agent(e, type == SSH_AGENTC_LOCK); 667 break; 668 /* ssh1 */ 669 case SSH_AGENTC_RSA_CHALLENGE: 670 process_authentication_challenge1(e); 671 break; 672 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 673 process_request_identities(e, 1); 674 break; 675 case SSH_AGENTC_ADD_RSA_IDENTITY: 676 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 677 process_add_identity(e, 1); 678 break; 679 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 680 process_remove_identity(e, 1); 681 break; 682 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 683 process_remove_all_identities(e, 1); 684 break; 685 /* ssh2 */ 686 case SSH2_AGENTC_SIGN_REQUEST: 687 process_sign_request2(e); 688 break; 689 case SSH2_AGENTC_REQUEST_IDENTITIES: 690 process_request_identities(e, 2); 691 break; 692 case SSH2_AGENTC_ADD_IDENTITY: 693 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 694 process_add_identity(e, 2); 695 break; 696 case SSH2_AGENTC_REMOVE_IDENTITY: 697 process_remove_identity(e, 2); 698 break; 699 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 700 process_remove_all_identities(e, 2); 701 break; 702 #ifdef SMARTCARD 703 case SSH_AGENTC_ADD_SMARTCARD_KEY: 704 process_add_smartcard_key(e); 705 break; 706 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 707 process_remove_smartcard_key(e); 708 break; 709 #endif /* SMARTCARD */ 710 default: 711 /* Unknown message. Respond with failure. */ 712 error("Unknown message %d", type); 713 buffer_clear(&e->request); 714 buffer_put_int(&e->output, 1); 715 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 716 break; 717 } 718 } 719 720 static void 721 new_socket(sock_type type, int fd) 722 { 723 u_int i, old_alloc; 724 725 if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) 726 error("fcntl O_NONBLOCK: %s", strerror(errno)); 727 728 if (fd > max_fd) 729 max_fd = fd; 730 731 for (i = 0; i < sockets_alloc; i++) 732 if (sockets[i].type == AUTH_UNUSED) { 733 sockets[i].fd = fd; 734 sockets[i].type = type; 735 buffer_init(&sockets[i].input); 736 buffer_init(&sockets[i].output); 737 buffer_init(&sockets[i].request); 738 return; 739 } 740 old_alloc = sockets_alloc; 741 sockets_alloc += 10; 742 if (sockets) 743 sockets = xrealloc(sockets, sockets_alloc * sizeof(sockets[0])); 744 else 745 sockets = xmalloc(sockets_alloc * sizeof(sockets[0])); 746 for (i = old_alloc; i < sockets_alloc; i++) 747 sockets[i].type = AUTH_UNUSED; 748 sockets[old_alloc].type = type; 749 sockets[old_alloc].fd = fd; 750 buffer_init(&sockets[old_alloc].input); 751 buffer_init(&sockets[old_alloc].output); 752 buffer_init(&sockets[old_alloc].request); 753 } 754 755 static int 756 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, int *nallocp) 757 { 758 u_int i, sz; 759 int n = 0; 760 761 for (i = 0; i < sockets_alloc; i++) { 762 switch (sockets[i].type) { 763 case AUTH_SOCKET: 764 case AUTH_CONNECTION: 765 n = MAX(n, sockets[i].fd); 766 break; 767 case AUTH_UNUSED: 768 break; 769 default: 770 fatal("Unknown socket type %d", sockets[i].type); 771 break; 772 } 773 } 774 775 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 776 if (*fdrp == NULL || sz > *nallocp) { 777 if (*fdrp) 778 xfree(*fdrp); 779 if (*fdwp) 780 xfree(*fdwp); 781 *fdrp = xmalloc(sz); 782 *fdwp = xmalloc(sz); 783 *nallocp = sz; 784 } 785 if (n < *fdl) 786 debug("XXX shrink: %d < %d", n, *fdl); 787 *fdl = n; 788 memset(*fdrp, 0, sz); 789 memset(*fdwp, 0, sz); 790 791 for (i = 0; i < sockets_alloc; i++) { 792 switch (sockets[i].type) { 793 case AUTH_SOCKET: 794 case AUTH_CONNECTION: 795 FD_SET(sockets[i].fd, *fdrp); 796 if (buffer_len(&sockets[i].output) > 0) 797 FD_SET(sockets[i].fd, *fdwp); 798 break; 799 default: 800 break; 801 } 802 } 803 return (1); 804 } 805 806 static void 807 after_select(fd_set *readset, fd_set *writeset) 808 { 809 struct sockaddr_un sunaddr; 810 socklen_t slen; 811 char buf[1024]; 812 int len, sock; 813 u_int i; 814 uid_t euid; 815 gid_t egid; 816 817 for (i = 0; i < sockets_alloc; i++) 818 switch (sockets[i].type) { 819 case AUTH_UNUSED: 820 break; 821 case AUTH_SOCKET: 822 if (FD_ISSET(sockets[i].fd, readset)) { 823 slen = sizeof(sunaddr); 824 sock = accept(sockets[i].fd, 825 (struct sockaddr *) &sunaddr, &slen); 826 if (sock < 0) { 827 error("accept from AUTH_SOCKET: %s", 828 strerror(errno)); 829 break; 830 } 831 if (getpeereid(sock, &euid, &egid) < 0) { 832 error("getpeereid %d failed: %s", 833 sock, strerror(errno)); 834 close(sock); 835 break; 836 } 837 if ((euid != 0) && (getuid() != euid)) { 838 error("uid mismatch: " 839 "peer euid %u != uid %u", 840 (u_int) euid, (u_int) getuid()); 841 close(sock); 842 break; 843 } 844 new_socket(AUTH_CONNECTION, sock); 845 } 846 break; 847 case AUTH_CONNECTION: 848 if (buffer_len(&sockets[i].output) > 0 && 849 FD_ISSET(sockets[i].fd, writeset)) { 850 do { 851 len = write(sockets[i].fd, 852 buffer_ptr(&sockets[i].output), 853 buffer_len(&sockets[i].output)); 854 if (len == -1 && (errno == EAGAIN || 855 errno == EINTR)) 856 continue; 857 break; 858 } while (1); 859 if (len <= 0) { 860 close_socket(&sockets[i]); 861 break; 862 } 863 buffer_consume(&sockets[i].output, len); 864 } 865 if (FD_ISSET(sockets[i].fd, readset)) { 866 do { 867 len = read(sockets[i].fd, buf, sizeof(buf)); 868 if (len == -1 && (errno == EAGAIN || 869 errno == EINTR)) 870 continue; 871 break; 872 } while (1); 873 if (len <= 0) { 874 close_socket(&sockets[i]); 875 break; 876 } 877 buffer_append(&sockets[i].input, buf, len); 878 process_message(&sockets[i]); 879 } 880 break; 881 default: 882 fatal("Unknown type %d", sockets[i].type); 883 } 884 } 885 886 static void 887 cleanup_socket(void *p) 888 { 889 if (socket_name[0]) 890 unlink(socket_name); 891 if (socket_dir[0]) 892 rmdir(socket_dir); 893 } 894 895 static void 896 cleanup_exit(int i) 897 { 898 cleanup_socket(NULL); 899 exit(i); 900 } 901 902 static void 903 cleanup_handler(int sig) 904 { 905 cleanup_socket(NULL); 906 _exit(2); 907 } 908 909 static void 910 check_parent_exists(int sig) 911 { 912 int save_errno = errno; 913 914 if (parent_pid != -1 && kill(parent_pid, 0) < 0) { 915 /* printf("Parent has died - Authentication agent exiting.\n"); */ 916 cleanup_handler(sig); /* safe */ 917 } 918 signal(SIGALRM, check_parent_exists); 919 alarm(10); 920 errno = save_errno; 921 } 922 923 static void 924 usage(void) 925 { 926 fprintf(stderr, "Usage: %s [options] [command [args ...]]\n", 927 __progname); 928 fprintf(stderr, "Options:\n"); 929 fprintf(stderr, " -c Generate C-shell commands on stdout.\n"); 930 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n"); 931 fprintf(stderr, " -k Kill the current agent.\n"); 932 fprintf(stderr, " -d Debug mode.\n"); 933 fprintf(stderr, " -a socket Bind agent socket to given name.\n"); 934 exit(1); 935 } 936 937 int 938 main(int ac, char **av) 939 { 940 int sock, c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0, ch, nalloc; 941 char *shell, *format, *pidstr, *agentsocket = NULL; 942 fd_set *readsetp = NULL, *writesetp = NULL; 943 struct sockaddr_un sunaddr; 944 #ifdef HAVE_SETRLIMIT 945 struct rlimit rlim; 946 #endif 947 #ifdef HAVE_CYGWIN 948 int prev_mask; 949 #endif 950 extern int optind; 951 extern char *optarg; 952 pid_t pid; 953 char pidstrbuf[1 + 3 * sizeof pid]; 954 955 /* drop */ 956 setegid(getgid()); 957 setgid(getgid()); 958 setuid(geteuid()); 959 960 SSLeay_add_all_algorithms(); 961 962 __progname = get_progname(av[0]); 963 init_rng(); 964 seed_rng(); 965 966 while ((ch = getopt(ac, av, "cdksa:")) != -1) { 967 switch (ch) { 968 case 'c': 969 if (s_flag) 970 usage(); 971 c_flag++; 972 break; 973 case 'k': 974 k_flag++; 975 break; 976 case 's': 977 if (c_flag) 978 usage(); 979 s_flag++; 980 break; 981 case 'd': 982 if (d_flag) 983 usage(); 984 d_flag++; 985 break; 986 case 'a': 987 agentsocket = optarg; 988 break; 989 default: 990 usage(); 991 } 992 } 993 ac -= optind; 994 av += optind; 995 996 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag)) 997 usage(); 998 999 if (ac == 0 && !c_flag && !s_flag) { 1000 shell = getenv("SHELL"); 1001 if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0) 1002 c_flag = 1; 1003 } 1004 if (k_flag) { 1005 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1006 if (pidstr == NULL) { 1007 fprintf(stderr, "%s not set, cannot kill agent\n", 1008 SSH_AGENTPID_ENV_NAME); 1009 exit(1); 1010 } 1011 pid = atoi(pidstr); 1012 if (pid < 1) { 1013 fprintf(stderr, "%s=\"%s\", which is not a good PID\n", 1014 SSH_AGENTPID_ENV_NAME, pidstr); 1015 exit(1); 1016 } 1017 if (kill(pid, SIGTERM) == -1) { 1018 perror("kill"); 1019 exit(1); 1020 } 1021 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 1022 printf(format, SSH_AUTHSOCKET_ENV_NAME); 1023 printf(format, SSH_AGENTPID_ENV_NAME); 1024 printf("echo Agent pid %ld killed;\n", (long)pid); 1025 exit(0); 1026 } 1027 parent_pid = getpid(); 1028 1029 if (agentsocket == NULL) { 1030 /* Create private directory for agent socket */ 1031 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXX", sizeof socket_dir); 1032 if (mkdtemp(socket_dir) == NULL) { 1033 perror("mkdtemp: private socket dir"); 1034 exit(1); 1035 } 1036 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1037 (long)parent_pid); 1038 } else { 1039 /* Try to use specified agent socket */ 1040 socket_dir[0] = '\0'; 1041 strlcpy(socket_name, agentsocket, sizeof socket_name); 1042 } 1043 1044 /* 1045 * Create socket early so it will exist before command gets run from 1046 * the parent. 1047 */ 1048 sock = socket(AF_UNIX, SOCK_STREAM, 0); 1049 if (sock < 0) { 1050 perror("socket"); 1051 cleanup_exit(1); 1052 } 1053 memset(&sunaddr, 0, sizeof(sunaddr)); 1054 sunaddr.sun_family = AF_UNIX; 1055 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); 1056 #ifdef HAVE_CYGWIN 1057 prev_mask = umask(0177); 1058 #endif 1059 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) { 1060 perror("bind"); 1061 #ifdef HAVE_CYGWIN 1062 umask(prev_mask); 1063 #endif 1064 cleanup_exit(1); 1065 } 1066 #ifdef HAVE_CYGWIN 1067 umask(prev_mask); 1068 #endif 1069 if (listen(sock, 128) < 0) { 1070 perror("listen"); 1071 cleanup_exit(1); 1072 } 1073 1074 /* 1075 * Fork, and have the parent execute the command, if any, or present 1076 * the socket data. The child continues as the authentication agent. 1077 */ 1078 if (d_flag) { 1079 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1); 1080 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1081 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1082 SSH_AUTHSOCKET_ENV_NAME); 1083 printf("echo Agent pid %ld;\n", (long)parent_pid); 1084 goto skip; 1085 } 1086 pid = fork(); 1087 if (pid == -1) { 1088 perror("fork"); 1089 cleanup_exit(1); 1090 } 1091 if (pid != 0) { /* Parent - execute the given command. */ 1092 close(sock); 1093 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1094 if (ac == 0) { 1095 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1096 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1097 SSH_AUTHSOCKET_ENV_NAME); 1098 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 1099 SSH_AGENTPID_ENV_NAME); 1100 printf("echo Agent pid %ld;\n", (long)pid); 1101 exit(0); 1102 } 1103 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1104 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1105 perror("setenv"); 1106 exit(1); 1107 } 1108 execvp(av[0], av); 1109 perror(av[0]); 1110 exit(1); 1111 } 1112 /* child */ 1113 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1114 1115 if (setsid() == -1) { 1116 error("setsid: %s", strerror(errno)); 1117 cleanup_exit(1); 1118 } 1119 1120 (void)chdir("/"); 1121 close(0); 1122 close(1); 1123 close(2); 1124 1125 #ifdef HAVE_SETRLIMIT 1126 /* deny core dumps, since memory contains unencrypted private keys */ 1127 rlim.rlim_cur = rlim.rlim_max = 0; 1128 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 1129 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1130 cleanup_exit(1); 1131 } 1132 #endif 1133 1134 skip: 1135 fatal_add_cleanup(cleanup_socket, NULL); 1136 new_socket(AUTH_SOCKET, sock); 1137 if (ac > 0) { 1138 signal(SIGALRM, check_parent_exists); 1139 alarm(10); 1140 } 1141 idtab_init(); 1142 if (!d_flag) 1143 signal(SIGINT, SIG_IGN); 1144 signal(SIGPIPE, SIG_IGN); 1145 signal(SIGHUP, cleanup_handler); 1146 signal(SIGTERM, cleanup_handler); 1147 nalloc = 0; 1148 1149 while (1) { 1150 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc); 1151 if (select(max_fd + 1, readsetp, writesetp, NULL, NULL) < 0) { 1152 if (errno == EINTR) 1153 continue; 1154 fatal("select: %s", strerror(errno)); 1155 } 1156 after_select(readsetp, writesetp); 1157 } 1158 /* NOTREACHED */ 1159 } 1160