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 1.124 2005/10/30 08:52:18 djm 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 "misc.h" 55 56 #ifdef SMARTCARD 57 #include "scard.h" 58 #endif 59 60 #if defined(HAVE_SYS_PRCTL_H) 61 #include <sys/prctl.h> /* For prctl() and PR_SET_DUMPABLE */ 62 #endif 63 64 typedef enum { 65 AUTH_UNUSED, 66 AUTH_SOCKET, 67 AUTH_CONNECTION 68 } sock_type; 69 70 typedef struct { 71 int fd; 72 sock_type type; 73 Buffer input; 74 Buffer output; 75 Buffer request; 76 } SocketEntry; 77 78 u_int sockets_alloc = 0; 79 SocketEntry *sockets = NULL; 80 81 typedef struct identity { 82 TAILQ_ENTRY(identity) next; 83 Key *key; 84 char *comment; 85 u_int death; 86 u_int confirm; 87 } Identity; 88 89 typedef struct { 90 int nentries; 91 TAILQ_HEAD(idqueue, identity) idlist; 92 } Idtab; 93 94 /* private key table, one per protocol version */ 95 Idtab idtable[3]; 96 97 int max_fd = 0; 98 99 /* pid of shell == parent of agent */ 100 pid_t parent_pid = -1; 101 102 /* pathname and directory for AUTH_SOCKET */ 103 char socket_name[1024]; 104 char socket_dir[1024]; 105 106 /* locking */ 107 int locked = 0; 108 char *lock_passwd = NULL; 109 110 extern char *__progname; 111 112 /* Default lifetime (0 == forever) */ 113 static int lifetime = 0; 114 115 static void 116 close_socket(SocketEntry *e) 117 { 118 close(e->fd); 119 e->fd = -1; 120 e->type = AUTH_UNUSED; 121 buffer_free(&e->input); 122 buffer_free(&e->output); 123 buffer_free(&e->request); 124 } 125 126 static void 127 idtab_init(void) 128 { 129 int i; 130 131 for (i = 0; i <=2; i++) { 132 TAILQ_INIT(&idtable[i].idlist); 133 idtable[i].nentries = 0; 134 } 135 } 136 137 /* return private key table for requested protocol version */ 138 static Idtab * 139 idtab_lookup(int version) 140 { 141 if (version < 1 || version > 2) 142 fatal("internal error, bad protocol version %d", version); 143 return &idtable[version]; 144 } 145 146 static void 147 free_identity(Identity *id) 148 { 149 key_free(id->key); 150 xfree(id->comment); 151 xfree(id); 152 } 153 154 /* return matching private key for given public key */ 155 static Identity * 156 lookup_identity(Key *key, int version) 157 { 158 Identity *id; 159 160 Idtab *tab = idtab_lookup(version); 161 TAILQ_FOREACH(id, &tab->idlist, next) { 162 if (key_equal(key, id->key)) 163 return (id); 164 } 165 return (NULL); 166 } 167 168 /* Check confirmation of keysign request */ 169 static int 170 confirm_key(Identity *id) 171 { 172 char *p; 173 int ret = -1; 174 175 p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX); 176 if (ask_permission("Allow use of key %s?\nKey fingerprint %s.", 177 id->comment, p)) 178 ret = 0; 179 xfree(p); 180 181 return (ret); 182 } 183 184 /* send list of supported public keys to 'client' */ 185 static void 186 process_request_identities(SocketEntry *e, int version) 187 { 188 Idtab *tab = idtab_lookup(version); 189 Identity *id; 190 Buffer msg; 191 192 buffer_init(&msg); 193 buffer_put_char(&msg, (version == 1) ? 194 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 195 buffer_put_int(&msg, tab->nentries); 196 TAILQ_FOREACH(id, &tab->idlist, next) { 197 if (id->key->type == KEY_RSA1) { 198 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n)); 199 buffer_put_bignum(&msg, id->key->rsa->e); 200 buffer_put_bignum(&msg, id->key->rsa->n); 201 } else { 202 u_char *blob; 203 u_int blen; 204 key_to_blob(id->key, &blob, &blen); 205 buffer_put_string(&msg, blob, blen); 206 xfree(blob); 207 } 208 buffer_put_cstring(&msg, id->comment); 209 } 210 buffer_put_int(&e->output, buffer_len(&msg)); 211 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 212 buffer_free(&msg); 213 } 214 215 /* ssh1 only */ 216 static void 217 process_authentication_challenge1(SocketEntry *e) 218 { 219 u_char buf[32], mdbuf[16], session_id[16]; 220 u_int response_type; 221 BIGNUM *challenge; 222 Identity *id; 223 int i, len; 224 Buffer msg; 225 MD5_CTX md; 226 Key *key; 227 228 buffer_init(&msg); 229 key = key_new(KEY_RSA1); 230 if ((challenge = BN_new()) == NULL) 231 fatal("process_authentication_challenge1: BN_new failed"); 232 233 (void) buffer_get_int(&e->request); /* ignored */ 234 buffer_get_bignum(&e->request, key->rsa->e); 235 buffer_get_bignum(&e->request, key->rsa->n); 236 buffer_get_bignum(&e->request, challenge); 237 238 /* Only protocol 1.1 is supported */ 239 if (buffer_len(&e->request) == 0) 240 goto failure; 241 buffer_get(&e->request, session_id, 16); 242 response_type = buffer_get_int(&e->request); 243 if (response_type != 1) 244 goto failure; 245 246 id = lookup_identity(key, 1); 247 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) { 248 Key *private = id->key; 249 /* Decrypt the challenge using the private key. */ 250 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0) 251 goto failure; 252 253 /* The response is MD5 of decrypted challenge plus session id. */ 254 len = BN_num_bytes(challenge); 255 if (len <= 0 || len > 32) { 256 logit("process_authentication_challenge: bad challenge length %d", len); 257 goto failure; 258 } 259 memset(buf, 0, 32); 260 BN_bn2bin(challenge, buf + 32 - len); 261 MD5_Init(&md); 262 MD5_Update(&md, buf, 32); 263 MD5_Update(&md, session_id, 16); 264 MD5_Final(mdbuf, &md); 265 266 /* Send the response. */ 267 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE); 268 for (i = 0; i < 16; i++) 269 buffer_put_char(&msg, mdbuf[i]); 270 goto send; 271 } 272 273 failure: 274 /* Unknown identity or protocol error. Send failure. */ 275 buffer_put_char(&msg, SSH_AGENT_FAILURE); 276 send: 277 buffer_put_int(&e->output, buffer_len(&msg)); 278 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 279 key_free(key); 280 BN_clear_free(challenge); 281 buffer_free(&msg); 282 } 283 284 /* ssh2 only */ 285 static void 286 process_sign_request2(SocketEntry *e) 287 { 288 u_char *blob, *data, *signature = NULL; 289 u_int blen, dlen, slen = 0; 290 extern int datafellows; 291 int ok = -1, flags; 292 Buffer msg; 293 Key *key; 294 295 datafellows = 0; 296 297 blob = buffer_get_string(&e->request, &blen); 298 data = buffer_get_string(&e->request, &dlen); 299 300 flags = buffer_get_int(&e->request); 301 if (flags & SSH_AGENT_OLD_SIGNATURE) 302 datafellows = SSH_BUG_SIGBLOB; 303 304 key = key_from_blob(blob, blen); 305 if (key != NULL) { 306 Identity *id = lookup_identity(key, 2); 307 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) 308 ok = key_sign(id->key, &signature, &slen, data, dlen); 309 } 310 key_free(key); 311 buffer_init(&msg); 312 if (ok == 0) { 313 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); 314 buffer_put_string(&msg, signature, slen); 315 } else { 316 buffer_put_char(&msg, SSH_AGENT_FAILURE); 317 } 318 buffer_put_int(&e->output, buffer_len(&msg)); 319 buffer_append(&e->output, buffer_ptr(&msg), 320 buffer_len(&msg)); 321 buffer_free(&msg); 322 xfree(data); 323 xfree(blob); 324 if (signature != NULL) 325 xfree(signature); 326 } 327 328 /* shared */ 329 static void 330 process_remove_identity(SocketEntry *e, int version) 331 { 332 u_int blen, bits; 333 int success = 0; 334 Key *key = NULL; 335 u_char *blob; 336 337 switch (version) { 338 case 1: 339 key = key_new(KEY_RSA1); 340 bits = buffer_get_int(&e->request); 341 buffer_get_bignum(&e->request, key->rsa->e); 342 buffer_get_bignum(&e->request, key->rsa->n); 343 344 if (bits != key_size(key)) 345 logit("Warning: identity keysize mismatch: actual %u, announced %u", 346 key_size(key), bits); 347 break; 348 case 2: 349 blob = buffer_get_string(&e->request, &blen); 350 key = key_from_blob(blob, blen); 351 xfree(blob); 352 break; 353 } 354 if (key != NULL) { 355 Identity *id = lookup_identity(key, version); 356 if (id != NULL) { 357 /* 358 * We have this key. Free the old key. Since we 359 * don't want to leave empty slots in the middle of 360 * the array, we actually free the key there and move 361 * all the entries between the empty slot and the end 362 * of the array. 363 */ 364 Idtab *tab = idtab_lookup(version); 365 if (tab->nentries < 1) 366 fatal("process_remove_identity: " 367 "internal error: tab->nentries %d", 368 tab->nentries); 369 TAILQ_REMOVE(&tab->idlist, id, next); 370 free_identity(id); 371 tab->nentries--; 372 success = 1; 373 } 374 key_free(key); 375 } 376 buffer_put_int(&e->output, 1); 377 buffer_put_char(&e->output, 378 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 379 } 380 381 static void 382 process_remove_all_identities(SocketEntry *e, int version) 383 { 384 Idtab *tab = idtab_lookup(version); 385 Identity *id; 386 387 /* Loop over all identities and clear the keys. */ 388 for (id = TAILQ_FIRST(&tab->idlist); id; 389 id = TAILQ_FIRST(&tab->idlist)) { 390 TAILQ_REMOVE(&tab->idlist, id, next); 391 free_identity(id); 392 } 393 394 /* Mark that there are no identities. */ 395 tab->nentries = 0; 396 397 /* Send success. */ 398 buffer_put_int(&e->output, 1); 399 buffer_put_char(&e->output, SSH_AGENT_SUCCESS); 400 } 401 402 static void 403 reaper(void) 404 { 405 u_int now = time(NULL); 406 Identity *id, *nxt; 407 int version; 408 Idtab *tab; 409 410 for (version = 1; version < 3; version++) { 411 tab = idtab_lookup(version); 412 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 413 nxt = TAILQ_NEXT(id, next); 414 if (id->death != 0 && now >= id->death) { 415 TAILQ_REMOVE(&tab->idlist, id, next); 416 free_identity(id); 417 tab->nentries--; 418 } 419 } 420 } 421 } 422 423 static void 424 process_add_identity(SocketEntry *e, int version) 425 { 426 Idtab *tab = idtab_lookup(version); 427 int type, success = 0, death = 0, confirm = 0; 428 char *type_name, *comment; 429 Key *k = NULL; 430 431 switch (version) { 432 case 1: 433 k = key_new_private(KEY_RSA1); 434 (void) buffer_get_int(&e->request); /* ignored */ 435 buffer_get_bignum(&e->request, k->rsa->n); 436 buffer_get_bignum(&e->request, k->rsa->e); 437 buffer_get_bignum(&e->request, k->rsa->d); 438 buffer_get_bignum(&e->request, k->rsa->iqmp); 439 440 /* SSH and SSL have p and q swapped */ 441 buffer_get_bignum(&e->request, k->rsa->q); /* p */ 442 buffer_get_bignum(&e->request, k->rsa->p); /* q */ 443 444 /* Generate additional parameters */ 445 rsa_generate_additional_parameters(k->rsa); 446 break; 447 case 2: 448 type_name = buffer_get_string(&e->request, NULL); 449 type = key_type_from_name(type_name); 450 xfree(type_name); 451 switch (type) { 452 case KEY_DSA: 453 k = key_new_private(type); 454 buffer_get_bignum2(&e->request, k->dsa->p); 455 buffer_get_bignum2(&e->request, k->dsa->q); 456 buffer_get_bignum2(&e->request, k->dsa->g); 457 buffer_get_bignum2(&e->request, k->dsa->pub_key); 458 buffer_get_bignum2(&e->request, k->dsa->priv_key); 459 break; 460 case KEY_RSA: 461 k = key_new_private(type); 462 buffer_get_bignum2(&e->request, k->rsa->n); 463 buffer_get_bignum2(&e->request, k->rsa->e); 464 buffer_get_bignum2(&e->request, k->rsa->d); 465 buffer_get_bignum2(&e->request, k->rsa->iqmp); 466 buffer_get_bignum2(&e->request, k->rsa->p); 467 buffer_get_bignum2(&e->request, k->rsa->q); 468 469 /* Generate additional parameters */ 470 rsa_generate_additional_parameters(k->rsa); 471 break; 472 default: 473 buffer_clear(&e->request); 474 goto send; 475 } 476 break; 477 } 478 /* enable blinding */ 479 switch (k->type) { 480 case KEY_RSA: 481 case KEY_RSA1: 482 if (RSA_blinding_on(k->rsa, NULL) != 1) { 483 error("process_add_identity: RSA_blinding_on failed"); 484 key_free(k); 485 goto send; 486 } 487 break; 488 } 489 comment = buffer_get_string(&e->request, NULL); 490 if (k == NULL) { 491 xfree(comment); 492 goto send; 493 } 494 success = 1; 495 while (buffer_len(&e->request)) { 496 switch (buffer_get_char(&e->request)) { 497 case SSH_AGENT_CONSTRAIN_LIFETIME: 498 death = time(NULL) + buffer_get_int(&e->request); 499 break; 500 case SSH_AGENT_CONSTRAIN_CONFIRM: 501 confirm = 1; 502 break; 503 default: 504 break; 505 } 506 } 507 if (lifetime && !death) 508 death = time(NULL) + lifetime; 509 if (lookup_identity(k, version) == NULL) { 510 Identity *id = xmalloc(sizeof(Identity)); 511 id->key = k; 512 id->comment = comment; 513 id->death = death; 514 id->confirm = confirm; 515 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 516 /* Increment the number of identities. */ 517 tab->nentries++; 518 } else { 519 key_free(k); 520 xfree(comment); 521 } 522 send: 523 buffer_put_int(&e->output, 1); 524 buffer_put_char(&e->output, 525 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 526 } 527 528 /* XXX todo: encrypt sensitive data with passphrase */ 529 static void 530 process_lock_agent(SocketEntry *e, int lock) 531 { 532 int success = 0; 533 char *passwd; 534 535 passwd = buffer_get_string(&e->request, NULL); 536 if (locked && !lock && strcmp(passwd, lock_passwd) == 0) { 537 locked = 0; 538 memset(lock_passwd, 0, strlen(lock_passwd)); 539 xfree(lock_passwd); 540 lock_passwd = NULL; 541 success = 1; 542 } else if (!locked && lock) { 543 locked = 1; 544 lock_passwd = xstrdup(passwd); 545 success = 1; 546 } 547 memset(passwd, 0, strlen(passwd)); 548 xfree(passwd); 549 550 buffer_put_int(&e->output, 1); 551 buffer_put_char(&e->output, 552 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 553 } 554 555 static void 556 no_identities(SocketEntry *e, u_int type) 557 { 558 Buffer msg; 559 560 buffer_init(&msg); 561 buffer_put_char(&msg, 562 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ? 563 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 564 buffer_put_int(&msg, 0); 565 buffer_put_int(&e->output, buffer_len(&msg)); 566 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 567 buffer_free(&msg); 568 } 569 570 #ifdef SMARTCARD 571 static void 572 process_add_smartcard_key (SocketEntry *e) 573 { 574 char *sc_reader_id = NULL, *pin; 575 int i, version, success = 0, death = 0, confirm = 0; 576 Key **keys, *k; 577 Identity *id; 578 Idtab *tab; 579 580 sc_reader_id = buffer_get_string(&e->request, NULL); 581 pin = buffer_get_string(&e->request, NULL); 582 583 while (buffer_len(&e->request)) { 584 switch (buffer_get_char(&e->request)) { 585 case SSH_AGENT_CONSTRAIN_LIFETIME: 586 death = time(NULL) + buffer_get_int(&e->request); 587 break; 588 case SSH_AGENT_CONSTRAIN_CONFIRM: 589 confirm = 1; 590 break; 591 default: 592 break; 593 } 594 } 595 if (lifetime && !death) 596 death = time(NULL) + lifetime; 597 598 keys = sc_get_keys(sc_reader_id, pin); 599 xfree(sc_reader_id); 600 xfree(pin); 601 602 if (keys == NULL || keys[0] == NULL) { 603 error("sc_get_keys failed"); 604 goto send; 605 } 606 for (i = 0; keys[i] != NULL; i++) { 607 k = keys[i]; 608 version = k->type == KEY_RSA1 ? 1 : 2; 609 tab = idtab_lookup(version); 610 if (lookup_identity(k, version) == NULL) { 611 id = xmalloc(sizeof(Identity)); 612 id->key = k; 613 id->comment = sc_get_key_label(k); 614 id->death = death; 615 id->confirm = confirm; 616 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 617 tab->nentries++; 618 success = 1; 619 } else { 620 key_free(k); 621 } 622 keys[i] = NULL; 623 } 624 xfree(keys); 625 send: 626 buffer_put_int(&e->output, 1); 627 buffer_put_char(&e->output, 628 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 629 } 630 631 static void 632 process_remove_smartcard_key(SocketEntry *e) 633 { 634 char *sc_reader_id = NULL, *pin; 635 int i, version, success = 0; 636 Key **keys, *k = NULL; 637 Identity *id; 638 Idtab *tab; 639 640 sc_reader_id = buffer_get_string(&e->request, NULL); 641 pin = buffer_get_string(&e->request, NULL); 642 keys = sc_get_keys(sc_reader_id, pin); 643 xfree(sc_reader_id); 644 xfree(pin); 645 646 if (keys == NULL || keys[0] == NULL) { 647 error("sc_get_keys failed"); 648 goto send; 649 } 650 for (i = 0; keys[i] != NULL; i++) { 651 k = keys[i]; 652 version = k->type == KEY_RSA1 ? 1 : 2; 653 if ((id = lookup_identity(k, version)) != NULL) { 654 tab = idtab_lookup(version); 655 TAILQ_REMOVE(&tab->idlist, id, next); 656 tab->nentries--; 657 free_identity(id); 658 success = 1; 659 } 660 key_free(k); 661 keys[i] = NULL; 662 } 663 xfree(keys); 664 send: 665 buffer_put_int(&e->output, 1); 666 buffer_put_char(&e->output, 667 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 668 } 669 #endif /* SMARTCARD */ 670 671 /* dispatch incoming messages */ 672 673 static void 674 process_message(SocketEntry *e) 675 { 676 u_int msg_len, type; 677 u_char *cp; 678 679 /* kill dead keys */ 680 reaper(); 681 682 if (buffer_len(&e->input) < 5) 683 return; /* Incomplete message. */ 684 cp = buffer_ptr(&e->input); 685 msg_len = GET_32BIT(cp); 686 if (msg_len > 256 * 1024) { 687 close_socket(e); 688 return; 689 } 690 if (buffer_len(&e->input) < msg_len + 4) 691 return; 692 693 /* move the current input to e->request */ 694 buffer_consume(&e->input, 4); 695 buffer_clear(&e->request); 696 buffer_append(&e->request, buffer_ptr(&e->input), msg_len); 697 buffer_consume(&e->input, msg_len); 698 type = buffer_get_char(&e->request); 699 700 /* check wheter agent is locked */ 701 if (locked && type != SSH_AGENTC_UNLOCK) { 702 buffer_clear(&e->request); 703 switch (type) { 704 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 705 case SSH2_AGENTC_REQUEST_IDENTITIES: 706 /* send empty lists */ 707 no_identities(e, type); 708 break; 709 default: 710 /* send a fail message for all other request types */ 711 buffer_put_int(&e->output, 1); 712 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 713 } 714 return; 715 } 716 717 debug("type %d", type); 718 switch (type) { 719 case SSH_AGENTC_LOCK: 720 case SSH_AGENTC_UNLOCK: 721 process_lock_agent(e, type == SSH_AGENTC_LOCK); 722 break; 723 /* ssh1 */ 724 case SSH_AGENTC_RSA_CHALLENGE: 725 process_authentication_challenge1(e); 726 break; 727 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 728 process_request_identities(e, 1); 729 break; 730 case SSH_AGENTC_ADD_RSA_IDENTITY: 731 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 732 process_add_identity(e, 1); 733 break; 734 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 735 process_remove_identity(e, 1); 736 break; 737 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 738 process_remove_all_identities(e, 1); 739 break; 740 /* ssh2 */ 741 case SSH2_AGENTC_SIGN_REQUEST: 742 process_sign_request2(e); 743 break; 744 case SSH2_AGENTC_REQUEST_IDENTITIES: 745 process_request_identities(e, 2); 746 break; 747 case SSH2_AGENTC_ADD_IDENTITY: 748 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 749 process_add_identity(e, 2); 750 break; 751 case SSH2_AGENTC_REMOVE_IDENTITY: 752 process_remove_identity(e, 2); 753 break; 754 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 755 process_remove_all_identities(e, 2); 756 break; 757 #ifdef SMARTCARD 758 case SSH_AGENTC_ADD_SMARTCARD_KEY: 759 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 760 process_add_smartcard_key(e); 761 break; 762 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 763 process_remove_smartcard_key(e); 764 break; 765 #endif /* SMARTCARD */ 766 default: 767 /* Unknown message. Respond with failure. */ 768 error("Unknown message %d", type); 769 buffer_clear(&e->request); 770 buffer_put_int(&e->output, 1); 771 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 772 break; 773 } 774 } 775 776 static void 777 new_socket(sock_type type, int fd) 778 { 779 u_int i, old_alloc, new_alloc; 780 781 set_nonblock(fd); 782 783 if (fd > max_fd) 784 max_fd = fd; 785 786 for (i = 0; i < sockets_alloc; i++) 787 if (sockets[i].type == AUTH_UNUSED) { 788 sockets[i].fd = fd; 789 buffer_init(&sockets[i].input); 790 buffer_init(&sockets[i].output); 791 buffer_init(&sockets[i].request); 792 sockets[i].type = type; 793 return; 794 } 795 old_alloc = sockets_alloc; 796 new_alloc = sockets_alloc + 10; 797 if (sockets) 798 sockets = xrealloc(sockets, new_alloc * sizeof(sockets[0])); 799 else 800 sockets = xmalloc(new_alloc * sizeof(sockets[0])); 801 for (i = old_alloc; i < new_alloc; i++) 802 sockets[i].type = AUTH_UNUSED; 803 sockets_alloc = new_alloc; 804 sockets[old_alloc].fd = fd; 805 buffer_init(&sockets[old_alloc].input); 806 buffer_init(&sockets[old_alloc].output); 807 buffer_init(&sockets[old_alloc].request); 808 sockets[old_alloc].type = type; 809 } 810 811 static int 812 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp) 813 { 814 u_int i, sz; 815 int n = 0; 816 817 for (i = 0; i < sockets_alloc; i++) { 818 switch (sockets[i].type) { 819 case AUTH_SOCKET: 820 case AUTH_CONNECTION: 821 n = MAX(n, sockets[i].fd); 822 break; 823 case AUTH_UNUSED: 824 break; 825 default: 826 fatal("Unknown socket type %d", sockets[i].type); 827 break; 828 } 829 } 830 831 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 832 if (*fdrp == NULL || sz > *nallocp) { 833 if (*fdrp) 834 xfree(*fdrp); 835 if (*fdwp) 836 xfree(*fdwp); 837 *fdrp = xmalloc(sz); 838 *fdwp = xmalloc(sz); 839 *nallocp = sz; 840 } 841 if (n < *fdl) 842 debug("XXX shrink: %d < %d", n, *fdl); 843 *fdl = n; 844 memset(*fdrp, 0, sz); 845 memset(*fdwp, 0, sz); 846 847 for (i = 0; i < sockets_alloc; i++) { 848 switch (sockets[i].type) { 849 case AUTH_SOCKET: 850 case AUTH_CONNECTION: 851 FD_SET(sockets[i].fd, *fdrp); 852 if (buffer_len(&sockets[i].output) > 0) 853 FD_SET(sockets[i].fd, *fdwp); 854 break; 855 default: 856 break; 857 } 858 } 859 return (1); 860 } 861 862 static void 863 after_select(fd_set *readset, fd_set *writeset) 864 { 865 struct sockaddr_un sunaddr; 866 socklen_t slen; 867 char buf[1024]; 868 int len, sock; 869 u_int i; 870 uid_t euid; 871 gid_t egid; 872 873 for (i = 0; i < sockets_alloc; i++) 874 switch (sockets[i].type) { 875 case AUTH_UNUSED: 876 break; 877 case AUTH_SOCKET: 878 if (FD_ISSET(sockets[i].fd, readset)) { 879 slen = sizeof(sunaddr); 880 sock = accept(sockets[i].fd, 881 (struct sockaddr *) &sunaddr, &slen); 882 if (sock < 0) { 883 error("accept from AUTH_SOCKET: %s", 884 strerror(errno)); 885 break; 886 } 887 if (getpeereid(sock, &euid, &egid) < 0) { 888 error("getpeereid %d failed: %s", 889 sock, strerror(errno)); 890 close(sock); 891 break; 892 } 893 if ((euid != 0) && (getuid() != euid)) { 894 error("uid mismatch: " 895 "peer euid %u != uid %u", 896 (u_int) euid, (u_int) getuid()); 897 close(sock); 898 break; 899 } 900 new_socket(AUTH_CONNECTION, sock); 901 } 902 break; 903 case AUTH_CONNECTION: 904 if (buffer_len(&sockets[i].output) > 0 && 905 FD_ISSET(sockets[i].fd, writeset)) { 906 do { 907 len = write(sockets[i].fd, 908 buffer_ptr(&sockets[i].output), 909 buffer_len(&sockets[i].output)); 910 if (len == -1 && (errno == EAGAIN || 911 errno == EINTR)) 912 continue; 913 break; 914 } while (1); 915 if (len <= 0) { 916 close_socket(&sockets[i]); 917 break; 918 } 919 buffer_consume(&sockets[i].output, len); 920 } 921 if (FD_ISSET(sockets[i].fd, readset)) { 922 do { 923 len = read(sockets[i].fd, buf, sizeof(buf)); 924 if (len == -1 && (errno == EAGAIN || 925 errno == EINTR)) 926 continue; 927 break; 928 } while (1); 929 if (len <= 0) { 930 close_socket(&sockets[i]); 931 break; 932 } 933 buffer_append(&sockets[i].input, buf, len); 934 process_message(&sockets[i]); 935 } 936 break; 937 default: 938 fatal("Unknown type %d", sockets[i].type); 939 } 940 } 941 942 static void 943 cleanup_socket(void) 944 { 945 if (socket_name[0]) 946 unlink(socket_name); 947 if (socket_dir[0]) 948 rmdir(socket_dir); 949 } 950 951 void 952 cleanup_exit(int i) 953 { 954 cleanup_socket(); 955 _exit(i); 956 } 957 958 static void 959 cleanup_handler(int sig) 960 { 961 cleanup_socket(); 962 _exit(2); 963 } 964 965 static void 966 check_parent_exists(int sig) 967 { 968 int save_errno = errno; 969 970 if (parent_pid != -1 && kill(parent_pid, 0) < 0) { 971 /* printf("Parent has died - Authentication agent exiting.\n"); */ 972 cleanup_handler(sig); /* safe */ 973 } 974 mysignal(SIGALRM, check_parent_exists); 975 alarm(10); 976 errno = save_errno; 977 } 978 979 static void 980 usage(void) 981 { 982 fprintf(stderr, "Usage: %s [options] [command [args ...]]\n", 983 __progname); 984 fprintf(stderr, "Options:\n"); 985 fprintf(stderr, " -c Generate C-shell commands on stdout.\n"); 986 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n"); 987 fprintf(stderr, " -k Kill the current agent.\n"); 988 fprintf(stderr, " -d Debug mode.\n"); 989 fprintf(stderr, " -a socket Bind agent socket to given name.\n"); 990 fprintf(stderr, " -t life Default identity lifetime (seconds).\n"); 991 exit(1); 992 } 993 994 int 995 main(int ac, char **av) 996 { 997 int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0; 998 int sock, fd, ch; 999 u_int nalloc; 1000 char *shell, *format, *pidstr, *agentsocket = NULL; 1001 fd_set *readsetp = NULL, *writesetp = NULL; 1002 struct sockaddr_un sunaddr; 1003 #ifdef HAVE_SETRLIMIT 1004 struct rlimit rlim; 1005 #endif 1006 int prev_mask; 1007 extern int optind; 1008 extern char *optarg; 1009 pid_t pid; 1010 char pidstrbuf[1 + 3 * sizeof pid]; 1011 1012 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1013 sanitise_stdfd(); 1014 1015 /* drop */ 1016 setegid(getgid()); 1017 setgid(getgid()); 1018 setuid(geteuid()); 1019 1020 #if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE) 1021 /* Disable ptrace on Linux without sgid bit */ 1022 prctl(PR_SET_DUMPABLE, 0); 1023 #endif 1024 1025 SSLeay_add_all_algorithms(); 1026 1027 __progname = ssh_get_progname(av[0]); 1028 init_rng(); 1029 seed_rng(); 1030 1031 while ((ch = getopt(ac, av, "cdksa:t:")) != -1) { 1032 switch (ch) { 1033 case 'c': 1034 if (s_flag) 1035 usage(); 1036 c_flag++; 1037 break; 1038 case 'k': 1039 k_flag++; 1040 break; 1041 case 's': 1042 if (c_flag) 1043 usage(); 1044 s_flag++; 1045 break; 1046 case 'd': 1047 if (d_flag) 1048 usage(); 1049 d_flag++; 1050 break; 1051 case 'a': 1052 agentsocket = optarg; 1053 break; 1054 case 't': 1055 if ((lifetime = convtime(optarg)) == -1) { 1056 fprintf(stderr, "Invalid lifetime\n"); 1057 usage(); 1058 } 1059 break; 1060 default: 1061 usage(); 1062 } 1063 } 1064 ac -= optind; 1065 av += optind; 1066 1067 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag)) 1068 usage(); 1069 1070 if (ac == 0 && !c_flag && !s_flag) { 1071 shell = getenv("SHELL"); 1072 if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0) 1073 c_flag = 1; 1074 } 1075 if (k_flag) { 1076 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1077 if (pidstr == NULL) { 1078 fprintf(stderr, "%s not set, cannot kill agent\n", 1079 SSH_AGENTPID_ENV_NAME); 1080 exit(1); 1081 } 1082 pid = atoi(pidstr); 1083 if (pid < 1) { 1084 fprintf(stderr, "%s=\"%s\", which is not a good PID\n", 1085 SSH_AGENTPID_ENV_NAME, pidstr); 1086 exit(1); 1087 } 1088 if (kill(pid, SIGTERM) == -1) { 1089 perror("kill"); 1090 exit(1); 1091 } 1092 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 1093 printf(format, SSH_AUTHSOCKET_ENV_NAME); 1094 printf(format, SSH_AGENTPID_ENV_NAME); 1095 printf("echo Agent pid %ld killed;\n", (long)pid); 1096 exit(0); 1097 } 1098 parent_pid = getpid(); 1099 1100 if (agentsocket == NULL) { 1101 /* Create private directory for agent socket */ 1102 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXXXX", sizeof socket_dir); 1103 if (mkdtemp(socket_dir) == NULL) { 1104 perror("mkdtemp: private socket dir"); 1105 exit(1); 1106 } 1107 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1108 (long)parent_pid); 1109 } else { 1110 /* Try to use specified agent socket */ 1111 socket_dir[0] = '\0'; 1112 strlcpy(socket_name, agentsocket, sizeof socket_name); 1113 } 1114 1115 /* 1116 * Create socket early so it will exist before command gets run from 1117 * the parent. 1118 */ 1119 sock = socket(AF_UNIX, SOCK_STREAM, 0); 1120 if (sock < 0) { 1121 perror("socket"); 1122 *socket_name = '\0'; /* Don't unlink any existing file */ 1123 cleanup_exit(1); 1124 } 1125 memset(&sunaddr, 0, sizeof(sunaddr)); 1126 sunaddr.sun_family = AF_UNIX; 1127 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); 1128 prev_mask = umask(0177); 1129 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) { 1130 perror("bind"); 1131 *socket_name = '\0'; /* Don't unlink any existing file */ 1132 umask(prev_mask); 1133 cleanup_exit(1); 1134 } 1135 umask(prev_mask); 1136 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 1137 perror("listen"); 1138 cleanup_exit(1); 1139 } 1140 1141 /* 1142 * Fork, and have the parent execute the command, if any, or present 1143 * the socket data. The child continues as the authentication agent. 1144 */ 1145 if (d_flag) { 1146 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1); 1147 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1148 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1149 SSH_AUTHSOCKET_ENV_NAME); 1150 printf("echo Agent pid %ld;\n", (long)parent_pid); 1151 goto skip; 1152 } 1153 pid = fork(); 1154 if (pid == -1) { 1155 perror("fork"); 1156 cleanup_exit(1); 1157 } 1158 if (pid != 0) { /* Parent - execute the given command. */ 1159 close(sock); 1160 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1161 if (ac == 0) { 1162 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1163 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1164 SSH_AUTHSOCKET_ENV_NAME); 1165 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 1166 SSH_AGENTPID_ENV_NAME); 1167 printf("echo Agent pid %ld;\n", (long)pid); 1168 exit(0); 1169 } 1170 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1171 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1172 perror("setenv"); 1173 exit(1); 1174 } 1175 execvp(av[0], av); 1176 perror(av[0]); 1177 exit(1); 1178 } 1179 /* child */ 1180 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1181 1182 if (setsid() == -1) { 1183 error("setsid: %s", strerror(errno)); 1184 cleanup_exit(1); 1185 } 1186 1187 (void)chdir("/"); 1188 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1189 /* XXX might close listen socket */ 1190 (void)dup2(fd, STDIN_FILENO); 1191 (void)dup2(fd, STDOUT_FILENO); 1192 (void)dup2(fd, STDERR_FILENO); 1193 if (fd > 2) 1194 close(fd); 1195 } 1196 1197 #ifdef HAVE_SETRLIMIT 1198 /* deny core dumps, since memory contains unencrypted private keys */ 1199 rlim.rlim_cur = rlim.rlim_max = 0; 1200 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 1201 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1202 cleanup_exit(1); 1203 } 1204 #endif 1205 1206 skip: 1207 new_socket(AUTH_SOCKET, sock); 1208 if (ac > 0) { 1209 mysignal(SIGALRM, check_parent_exists); 1210 alarm(10); 1211 } 1212 idtab_init(); 1213 if (!d_flag) 1214 signal(SIGINT, SIG_IGN); 1215 signal(SIGPIPE, SIG_IGN); 1216 signal(SIGHUP, cleanup_handler); 1217 signal(SIGTERM, cleanup_handler); 1218 nalloc = 0; 1219 1220 while (1) { 1221 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc); 1222 if (select(max_fd + 1, readsetp, writesetp, NULL, NULL) < 0) { 1223 if (errno == EINTR) 1224 continue; 1225 fatal("select: %s", strerror(errno)); 1226 } 1227 after_select(readsetp, writesetp); 1228 } 1229 /* NOTREACHED */ 1230 } 1231