1 /* 2 * Author: Tatu Ylonen <ylo@cs.hut.fi> 3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 4 * All rights reserved 5 * The authentication agent program. 6 * 7 * As far as I am concerned, the code I have written for this software 8 * can be used freely for any purpose. Any derived versions of this 9 * software must be clearly marked as such, and if the derived work is 10 * incompatible with the protocol description in the RFC file, it must be 11 * called by a name other than "ssh" or "Secure Shell". 12 * 13 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 14 * 15 * Redistribution and use in source and binary forms, with or without 16 * modification, are permitted provided that the following conditions 17 * are met: 18 * 1. Redistributions of source code must retain the above copyright 19 * notice, this list of conditions and the following disclaimer. 20 * 2. Redistributions in binary form must reproduce the above copyright 21 * notice, this list of conditions and the following disclaimer in the 22 * documentation and/or other materials provided with the distribution. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 27 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 29 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34 */ 35 36 #include "includes.h" 37 #include "openbsd-compat/sys-queue.h" 38 RCSID("$OpenBSD: ssh-agent.c,v 1.117 2003/12/02 17:01:15 markus Exp $"); 39 RCSID("$FreeBSD$"); 40 41 #include <openssl/evp.h> 42 #include <openssl/md5.h> 43 44 #include "ssh.h" 45 #include "rsa.h" 46 #include "buffer.h" 47 #include "bufaux.h" 48 #include "xmalloc.h" 49 #include "getput.h" 50 #include "key.h" 51 #include "authfd.h" 52 #include "compat.h" 53 #include "log.h" 54 #include "readpass.h" 55 #include "misc.h" 56 57 #ifdef SMARTCARD 58 #include "scard.h" 59 #endif 60 61 #if defined(HAVE_SYS_PRCTL_H) 62 #include <sys/prctl.h> /* For prctl() and PR_SET_DUMPABLE */ 63 #endif 64 65 typedef enum { 66 AUTH_UNUSED, 67 AUTH_SOCKET, 68 AUTH_CONNECTION 69 } sock_type; 70 71 typedef struct { 72 int fd; 73 sock_type type; 74 Buffer input; 75 Buffer output; 76 Buffer request; 77 } SocketEntry; 78 79 u_int sockets_alloc = 0; 80 SocketEntry *sockets = NULL; 81 82 typedef struct identity { 83 TAILQ_ENTRY(identity) next; 84 Key *key; 85 char *comment; 86 u_int death; 87 u_int confirm; 88 } Identity; 89 90 typedef struct { 91 int nentries; 92 TAILQ_HEAD(idqueue, identity) idlist; 93 } Idtab; 94 95 /* private key table, one per protocol version */ 96 Idtab idtable[3]; 97 98 int max_fd = 0; 99 100 /* pid of shell == parent of agent */ 101 pid_t parent_pid = -1; 102 103 /* pathname and directory for AUTH_SOCKET */ 104 char socket_name[1024]; 105 char socket_dir[1024]; 106 107 /* locking */ 108 int locked = 0; 109 char *lock_passwd = NULL; 110 111 #ifdef HAVE___PROGNAME 112 extern char *__progname; 113 #else 114 char *__progname; 115 #endif 116 117 /* Default lifetime (0 == forever) */ 118 static int lifetime = 0; 119 120 static void 121 close_socket(SocketEntry *e) 122 { 123 close(e->fd); 124 e->fd = -1; 125 e->type = AUTH_UNUSED; 126 buffer_free(&e->input); 127 buffer_free(&e->output); 128 buffer_free(&e->request); 129 } 130 131 static void 132 idtab_init(void) 133 { 134 int i; 135 136 for (i = 0; i <=2; i++) { 137 TAILQ_INIT(&idtable[i].idlist); 138 idtable[i].nentries = 0; 139 } 140 } 141 142 /* return private key table for requested protocol version */ 143 static Idtab * 144 idtab_lookup(int version) 145 { 146 if (version < 1 || version > 2) 147 fatal("internal error, bad protocol version %d", version); 148 return &idtable[version]; 149 } 150 151 static void 152 free_identity(Identity *id) 153 { 154 key_free(id->key); 155 xfree(id->comment); 156 xfree(id); 157 } 158 159 /* return matching private key for given public key */ 160 static Identity * 161 lookup_identity(Key *key, int version) 162 { 163 Identity *id; 164 165 Idtab *tab = idtab_lookup(version); 166 TAILQ_FOREACH(id, &tab->idlist, next) { 167 if (key_equal(key, id->key)) 168 return (id); 169 } 170 return (NULL); 171 } 172 173 /* Check confirmation of keysign request */ 174 static int 175 confirm_key(Identity *id) 176 { 177 char *p, prompt[1024]; 178 int ret = -1; 179 180 p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX); 181 snprintf(prompt, sizeof(prompt), "Allow use of key %s?\n" 182 "Key fingerprint %s.", id->comment, p); 183 xfree(p); 184 p = read_passphrase(prompt, RP_ALLOW_EOF); 185 if (p != NULL) { 186 /* 187 * Accept empty responses and responses consisting 188 * of the word "yes" as affirmative. 189 */ 190 if (*p == '\0' || *p == '\n' || strcasecmp(p, "yes") == 0) 191 ret = 0; 192 xfree(p); 193 } 194 return (ret); 195 } 196 197 /* send list of supported public keys to 'client' */ 198 static void 199 process_request_identities(SocketEntry *e, int version) 200 { 201 Idtab *tab = idtab_lookup(version); 202 Identity *id; 203 Buffer msg; 204 205 buffer_init(&msg); 206 buffer_put_char(&msg, (version == 1) ? 207 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 208 buffer_put_int(&msg, tab->nentries); 209 TAILQ_FOREACH(id, &tab->idlist, next) { 210 if (id->key->type == KEY_RSA1) { 211 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n)); 212 buffer_put_bignum(&msg, id->key->rsa->e); 213 buffer_put_bignum(&msg, id->key->rsa->n); 214 } else { 215 u_char *blob; 216 u_int blen; 217 key_to_blob(id->key, &blob, &blen); 218 buffer_put_string(&msg, blob, blen); 219 xfree(blob); 220 } 221 buffer_put_cstring(&msg, id->comment); 222 } 223 buffer_put_int(&e->output, buffer_len(&msg)); 224 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 225 buffer_free(&msg); 226 } 227 228 /* ssh1 only */ 229 static void 230 process_authentication_challenge1(SocketEntry *e) 231 { 232 u_char buf[32], mdbuf[16], session_id[16]; 233 u_int response_type; 234 BIGNUM *challenge; 235 Identity *id; 236 int i, len; 237 Buffer msg; 238 MD5_CTX md; 239 Key *key; 240 241 buffer_init(&msg); 242 key = key_new(KEY_RSA1); 243 if ((challenge = BN_new()) == NULL) 244 fatal("process_authentication_challenge1: BN_new failed"); 245 246 (void) buffer_get_int(&e->request); /* ignored */ 247 buffer_get_bignum(&e->request, key->rsa->e); 248 buffer_get_bignum(&e->request, key->rsa->n); 249 buffer_get_bignum(&e->request, challenge); 250 251 /* Only protocol 1.1 is supported */ 252 if (buffer_len(&e->request) == 0) 253 goto failure; 254 buffer_get(&e->request, session_id, 16); 255 response_type = buffer_get_int(&e->request); 256 if (response_type != 1) 257 goto failure; 258 259 id = lookup_identity(key, 1); 260 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) { 261 Key *private = id->key; 262 /* Decrypt the challenge using the private key. */ 263 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0) 264 goto failure; 265 266 /* The response is MD5 of decrypted challenge plus session id. */ 267 len = BN_num_bytes(challenge); 268 if (len <= 0 || len > 32) { 269 logit("process_authentication_challenge: bad challenge length %d", len); 270 goto failure; 271 } 272 memset(buf, 0, 32); 273 BN_bn2bin(challenge, buf + 32 - len); 274 MD5_Init(&md); 275 MD5_Update(&md, buf, 32); 276 MD5_Update(&md, session_id, 16); 277 MD5_Final(mdbuf, &md); 278 279 /* Send the response. */ 280 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE); 281 for (i = 0; i < 16; i++) 282 buffer_put_char(&msg, mdbuf[i]); 283 goto send; 284 } 285 286 failure: 287 /* Unknown identity or protocol error. Send failure. */ 288 buffer_put_char(&msg, SSH_AGENT_FAILURE); 289 send: 290 buffer_put_int(&e->output, buffer_len(&msg)); 291 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 292 key_free(key); 293 BN_clear_free(challenge); 294 buffer_free(&msg); 295 } 296 297 /* ssh2 only */ 298 static void 299 process_sign_request2(SocketEntry *e) 300 { 301 u_char *blob, *data, *signature = NULL; 302 u_int blen, dlen, slen = 0; 303 extern int datafellows; 304 int ok = -1, flags; 305 Buffer msg; 306 Key *key; 307 308 datafellows = 0; 309 310 blob = buffer_get_string(&e->request, &blen); 311 data = buffer_get_string(&e->request, &dlen); 312 313 flags = buffer_get_int(&e->request); 314 if (flags & SSH_AGENT_OLD_SIGNATURE) 315 datafellows = SSH_BUG_SIGBLOB; 316 317 key = key_from_blob(blob, blen); 318 if (key != NULL) { 319 Identity *id = lookup_identity(key, 2); 320 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) 321 ok = key_sign(id->key, &signature, &slen, data, dlen); 322 } 323 key_free(key); 324 buffer_init(&msg); 325 if (ok == 0) { 326 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); 327 buffer_put_string(&msg, signature, slen); 328 } else { 329 buffer_put_char(&msg, SSH_AGENT_FAILURE); 330 } 331 buffer_put_int(&e->output, buffer_len(&msg)); 332 buffer_append(&e->output, buffer_ptr(&msg), 333 buffer_len(&msg)); 334 buffer_free(&msg); 335 xfree(data); 336 xfree(blob); 337 if (signature != NULL) 338 xfree(signature); 339 } 340 341 /* shared */ 342 static void 343 process_remove_identity(SocketEntry *e, int version) 344 { 345 u_int blen, bits; 346 int success = 0; 347 Key *key = NULL; 348 u_char *blob; 349 350 switch (version) { 351 case 1: 352 key = key_new(KEY_RSA1); 353 bits = buffer_get_int(&e->request); 354 buffer_get_bignum(&e->request, key->rsa->e); 355 buffer_get_bignum(&e->request, key->rsa->n); 356 357 if (bits != key_size(key)) 358 logit("Warning: identity keysize mismatch: actual %u, announced %u", 359 key_size(key), bits); 360 break; 361 case 2: 362 blob = buffer_get_string(&e->request, &blen); 363 key = key_from_blob(blob, blen); 364 xfree(blob); 365 break; 366 } 367 if (key != NULL) { 368 Identity *id = lookup_identity(key, version); 369 if (id != NULL) { 370 /* 371 * We have this key. Free the old key. Since we 372 * don\'t want to leave empty slots in the middle of 373 * the array, we actually free the key there and move 374 * all the entries between the empty slot and the end 375 * of the array. 376 */ 377 Idtab *tab = idtab_lookup(version); 378 if (tab->nentries < 1) 379 fatal("process_remove_identity: " 380 "internal error: tab->nentries %d", 381 tab->nentries); 382 TAILQ_REMOVE(&tab->idlist, id, next); 383 free_identity(id); 384 tab->nentries--; 385 success = 1; 386 } 387 key_free(key); 388 } 389 buffer_put_int(&e->output, 1); 390 buffer_put_char(&e->output, 391 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 392 } 393 394 static void 395 process_remove_all_identities(SocketEntry *e, int version) 396 { 397 Idtab *tab = idtab_lookup(version); 398 Identity *id; 399 400 /* Loop over all identities and clear the keys. */ 401 for (id = TAILQ_FIRST(&tab->idlist); id; 402 id = TAILQ_FIRST(&tab->idlist)) { 403 TAILQ_REMOVE(&tab->idlist, id, next); 404 free_identity(id); 405 } 406 407 /* Mark that there are no identities. */ 408 tab->nentries = 0; 409 410 /* Send success. */ 411 buffer_put_int(&e->output, 1); 412 buffer_put_char(&e->output, SSH_AGENT_SUCCESS); 413 } 414 415 static void 416 reaper(void) 417 { 418 u_int now = time(NULL); 419 Identity *id, *nxt; 420 int version; 421 Idtab *tab; 422 423 for (version = 1; version < 3; version++) { 424 tab = idtab_lookup(version); 425 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 426 nxt = TAILQ_NEXT(id, next); 427 if (id->death != 0 && now >= id->death) { 428 TAILQ_REMOVE(&tab->idlist, id, next); 429 free_identity(id); 430 tab->nentries--; 431 } 432 } 433 } 434 } 435 436 static void 437 process_add_identity(SocketEntry *e, int version) 438 { 439 Idtab *tab = idtab_lookup(version); 440 int type, success = 0, death = 0, confirm = 0; 441 char *type_name, *comment; 442 Key *k = NULL; 443 444 switch (version) { 445 case 1: 446 k = key_new_private(KEY_RSA1); 447 (void) buffer_get_int(&e->request); /* ignored */ 448 buffer_get_bignum(&e->request, k->rsa->n); 449 buffer_get_bignum(&e->request, k->rsa->e); 450 buffer_get_bignum(&e->request, k->rsa->d); 451 buffer_get_bignum(&e->request, k->rsa->iqmp); 452 453 /* SSH and SSL have p and q swapped */ 454 buffer_get_bignum(&e->request, k->rsa->q); /* p */ 455 buffer_get_bignum(&e->request, k->rsa->p); /* q */ 456 457 /* Generate additional parameters */ 458 rsa_generate_additional_parameters(k->rsa); 459 break; 460 case 2: 461 type_name = buffer_get_string(&e->request, NULL); 462 type = key_type_from_name(type_name); 463 xfree(type_name); 464 switch (type) { 465 case KEY_DSA: 466 k = key_new_private(type); 467 buffer_get_bignum2(&e->request, k->dsa->p); 468 buffer_get_bignum2(&e->request, k->dsa->q); 469 buffer_get_bignum2(&e->request, k->dsa->g); 470 buffer_get_bignum2(&e->request, k->dsa->pub_key); 471 buffer_get_bignum2(&e->request, k->dsa->priv_key); 472 break; 473 case KEY_RSA: 474 k = key_new_private(type); 475 buffer_get_bignum2(&e->request, k->rsa->n); 476 buffer_get_bignum2(&e->request, k->rsa->e); 477 buffer_get_bignum2(&e->request, k->rsa->d); 478 buffer_get_bignum2(&e->request, k->rsa->iqmp); 479 buffer_get_bignum2(&e->request, k->rsa->p); 480 buffer_get_bignum2(&e->request, k->rsa->q); 481 482 /* Generate additional parameters */ 483 rsa_generate_additional_parameters(k->rsa); 484 break; 485 default: 486 buffer_clear(&e->request); 487 goto send; 488 } 489 break; 490 } 491 /* enable blinding */ 492 switch (k->type) { 493 case KEY_RSA: 494 case KEY_RSA1: 495 if (RSA_blinding_on(k->rsa, NULL) != 1) { 496 error("process_add_identity: RSA_blinding_on failed"); 497 key_free(k); 498 goto send; 499 } 500 break; 501 } 502 comment = buffer_get_string(&e->request, NULL); 503 if (k == NULL) { 504 xfree(comment); 505 goto send; 506 } 507 success = 1; 508 while (buffer_len(&e->request)) { 509 switch (buffer_get_char(&e->request)) { 510 case SSH_AGENT_CONSTRAIN_LIFETIME: 511 death = time(NULL) + buffer_get_int(&e->request); 512 break; 513 case SSH_AGENT_CONSTRAIN_CONFIRM: 514 confirm = 1; 515 break; 516 default: 517 break; 518 } 519 } 520 if (lifetime && !death) 521 death = time(NULL) + lifetime; 522 if (lookup_identity(k, version) == NULL) { 523 Identity *id = xmalloc(sizeof(Identity)); 524 id->key = k; 525 id->comment = comment; 526 id->death = death; 527 id->confirm = confirm; 528 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 529 /* Increment the number of identities. */ 530 tab->nentries++; 531 } else { 532 key_free(k); 533 xfree(comment); 534 } 535 send: 536 buffer_put_int(&e->output, 1); 537 buffer_put_char(&e->output, 538 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 539 } 540 541 /* XXX todo: encrypt sensitive data with passphrase */ 542 static void 543 process_lock_agent(SocketEntry *e, int lock) 544 { 545 int success = 0; 546 char *passwd; 547 548 passwd = buffer_get_string(&e->request, NULL); 549 if (locked && !lock && strcmp(passwd, lock_passwd) == 0) { 550 locked = 0; 551 memset(lock_passwd, 0, strlen(lock_passwd)); 552 xfree(lock_passwd); 553 lock_passwd = NULL; 554 success = 1; 555 } else if (!locked && lock) { 556 locked = 1; 557 lock_passwd = xstrdup(passwd); 558 success = 1; 559 } 560 memset(passwd, 0, strlen(passwd)); 561 xfree(passwd); 562 563 buffer_put_int(&e->output, 1); 564 buffer_put_char(&e->output, 565 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 566 } 567 568 static void 569 no_identities(SocketEntry *e, u_int type) 570 { 571 Buffer msg; 572 573 buffer_init(&msg); 574 buffer_put_char(&msg, 575 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ? 576 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 577 buffer_put_int(&msg, 0); 578 buffer_put_int(&e->output, buffer_len(&msg)); 579 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 580 buffer_free(&msg); 581 } 582 583 #ifdef SMARTCARD 584 static void 585 process_add_smartcard_key (SocketEntry *e) 586 { 587 char *sc_reader_id = NULL, *pin; 588 int i, version, success = 0, death = 0, confirm = 0; 589 Key **keys, *k; 590 Identity *id; 591 Idtab *tab; 592 593 sc_reader_id = buffer_get_string(&e->request, NULL); 594 pin = buffer_get_string(&e->request, NULL); 595 596 while (buffer_len(&e->request)) { 597 switch (buffer_get_char(&e->request)) { 598 case SSH_AGENT_CONSTRAIN_LIFETIME: 599 death = time(NULL) + buffer_get_int(&e->request); 600 break; 601 case SSH_AGENT_CONSTRAIN_CONFIRM: 602 confirm = 1; 603 break; 604 default: 605 break; 606 } 607 } 608 if (lifetime && !death) 609 death = time(NULL) + lifetime; 610 611 keys = sc_get_keys(sc_reader_id, pin); 612 xfree(sc_reader_id); 613 xfree(pin); 614 615 if (keys == NULL || keys[0] == NULL) { 616 error("sc_get_keys failed"); 617 goto send; 618 } 619 for (i = 0; keys[i] != NULL; i++) { 620 k = keys[i]; 621 version = k->type == KEY_RSA1 ? 1 : 2; 622 tab = idtab_lookup(version); 623 if (lookup_identity(k, version) == NULL) { 624 id = xmalloc(sizeof(Identity)); 625 id->key = k; 626 id->comment = sc_get_key_label(k); 627 id->death = death; 628 id->confirm = confirm; 629 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 630 tab->nentries++; 631 success = 1; 632 } else { 633 key_free(k); 634 } 635 keys[i] = NULL; 636 } 637 xfree(keys); 638 send: 639 buffer_put_int(&e->output, 1); 640 buffer_put_char(&e->output, 641 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 642 } 643 644 static void 645 process_remove_smartcard_key(SocketEntry *e) 646 { 647 char *sc_reader_id = NULL, *pin; 648 int i, version, success = 0; 649 Key **keys, *k = NULL; 650 Identity *id; 651 Idtab *tab; 652 653 sc_reader_id = buffer_get_string(&e->request, NULL); 654 pin = buffer_get_string(&e->request, NULL); 655 keys = sc_get_keys(sc_reader_id, pin); 656 xfree(sc_reader_id); 657 xfree(pin); 658 659 if (keys == NULL || keys[0] == NULL) { 660 error("sc_get_keys failed"); 661 goto send; 662 } 663 for (i = 0; keys[i] != NULL; i++) { 664 k = keys[i]; 665 version = k->type == KEY_RSA1 ? 1 : 2; 666 if ((id = lookup_identity(k, version)) != NULL) { 667 tab = idtab_lookup(version); 668 TAILQ_REMOVE(&tab->idlist, id, next); 669 tab->nentries--; 670 free_identity(id); 671 success = 1; 672 } 673 key_free(k); 674 keys[i] = NULL; 675 } 676 xfree(keys); 677 send: 678 buffer_put_int(&e->output, 1); 679 buffer_put_char(&e->output, 680 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 681 } 682 #endif /* SMARTCARD */ 683 684 /* dispatch incoming messages */ 685 686 static void 687 process_message(SocketEntry *e) 688 { 689 u_int msg_len, type; 690 u_char *cp; 691 692 /* kill dead keys */ 693 reaper(); 694 695 if (buffer_len(&e->input) < 5) 696 return; /* Incomplete message. */ 697 cp = buffer_ptr(&e->input); 698 msg_len = GET_32BIT(cp); 699 if (msg_len > 256 * 1024) { 700 close_socket(e); 701 return; 702 } 703 if (buffer_len(&e->input) < msg_len + 4) 704 return; 705 706 /* move the current input to e->request */ 707 buffer_consume(&e->input, 4); 708 buffer_clear(&e->request); 709 buffer_append(&e->request, buffer_ptr(&e->input), msg_len); 710 buffer_consume(&e->input, msg_len); 711 type = buffer_get_char(&e->request); 712 713 /* check wheter agent is locked */ 714 if (locked && type != SSH_AGENTC_UNLOCK) { 715 buffer_clear(&e->request); 716 switch (type) { 717 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 718 case SSH2_AGENTC_REQUEST_IDENTITIES: 719 /* send empty lists */ 720 no_identities(e, type); 721 break; 722 default: 723 /* send a fail message for all other request types */ 724 buffer_put_int(&e->output, 1); 725 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 726 } 727 return; 728 } 729 730 debug("type %d", type); 731 switch (type) { 732 case SSH_AGENTC_LOCK: 733 case SSH_AGENTC_UNLOCK: 734 process_lock_agent(e, type == SSH_AGENTC_LOCK); 735 break; 736 /* ssh1 */ 737 case SSH_AGENTC_RSA_CHALLENGE: 738 process_authentication_challenge1(e); 739 break; 740 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 741 process_request_identities(e, 1); 742 break; 743 case SSH_AGENTC_ADD_RSA_IDENTITY: 744 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 745 process_add_identity(e, 1); 746 break; 747 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 748 process_remove_identity(e, 1); 749 break; 750 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 751 process_remove_all_identities(e, 1); 752 break; 753 /* ssh2 */ 754 case SSH2_AGENTC_SIGN_REQUEST: 755 process_sign_request2(e); 756 break; 757 case SSH2_AGENTC_REQUEST_IDENTITIES: 758 process_request_identities(e, 2); 759 break; 760 case SSH2_AGENTC_ADD_IDENTITY: 761 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 762 process_add_identity(e, 2); 763 break; 764 case SSH2_AGENTC_REMOVE_IDENTITY: 765 process_remove_identity(e, 2); 766 break; 767 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 768 process_remove_all_identities(e, 2); 769 break; 770 #ifdef SMARTCARD 771 case SSH_AGENTC_ADD_SMARTCARD_KEY: 772 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 773 process_add_smartcard_key(e); 774 break; 775 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 776 process_remove_smartcard_key(e); 777 break; 778 #endif /* SMARTCARD */ 779 default: 780 /* Unknown message. Respond with failure. */ 781 error("Unknown message %d", type); 782 buffer_clear(&e->request); 783 buffer_put_int(&e->output, 1); 784 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 785 break; 786 } 787 } 788 789 static void 790 new_socket(sock_type type, int fd) 791 { 792 u_int i, old_alloc, new_alloc; 793 794 if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) 795 error("fcntl O_NONBLOCK: %s", strerror(errno)); 796 797 if (fd > max_fd) 798 max_fd = fd; 799 800 for (i = 0; i < sockets_alloc; i++) 801 if (sockets[i].type == AUTH_UNUSED) { 802 sockets[i].fd = fd; 803 buffer_init(&sockets[i].input); 804 buffer_init(&sockets[i].output); 805 buffer_init(&sockets[i].request); 806 sockets[i].type = type; 807 return; 808 } 809 old_alloc = sockets_alloc; 810 new_alloc = sockets_alloc + 10; 811 if (sockets) 812 sockets = xrealloc(sockets, new_alloc * sizeof(sockets[0])); 813 else 814 sockets = xmalloc(new_alloc * sizeof(sockets[0])); 815 for (i = old_alloc; i < new_alloc; i++) 816 sockets[i].type = AUTH_UNUSED; 817 sockets_alloc = new_alloc; 818 sockets[old_alloc].fd = fd; 819 buffer_init(&sockets[old_alloc].input); 820 buffer_init(&sockets[old_alloc].output); 821 buffer_init(&sockets[old_alloc].request); 822 sockets[old_alloc].type = type; 823 } 824 825 static int 826 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, int *nallocp) 827 { 828 u_int i, sz; 829 int n = 0; 830 831 for (i = 0; i < sockets_alloc; i++) { 832 switch (sockets[i].type) { 833 case AUTH_SOCKET: 834 case AUTH_CONNECTION: 835 n = MAX(n, sockets[i].fd); 836 break; 837 case AUTH_UNUSED: 838 break; 839 default: 840 fatal("Unknown socket type %d", sockets[i].type); 841 break; 842 } 843 } 844 845 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 846 if (*fdrp == NULL || sz > *nallocp) { 847 if (*fdrp) 848 xfree(*fdrp); 849 if (*fdwp) 850 xfree(*fdwp); 851 *fdrp = xmalloc(sz); 852 *fdwp = xmalloc(sz); 853 *nallocp = sz; 854 } 855 if (n < *fdl) 856 debug("XXX shrink: %d < %d", n, *fdl); 857 *fdl = n; 858 memset(*fdrp, 0, sz); 859 memset(*fdwp, 0, sz); 860 861 for (i = 0; i < sockets_alloc; i++) { 862 switch (sockets[i].type) { 863 case AUTH_SOCKET: 864 case AUTH_CONNECTION: 865 FD_SET(sockets[i].fd, *fdrp); 866 if (buffer_len(&sockets[i].output) > 0) 867 FD_SET(sockets[i].fd, *fdwp); 868 break; 869 default: 870 break; 871 } 872 } 873 return (1); 874 } 875 876 static void 877 after_select(fd_set *readset, fd_set *writeset) 878 { 879 struct sockaddr_un sunaddr; 880 socklen_t slen; 881 char buf[1024]; 882 int len, sock; 883 u_int i; 884 uid_t euid; 885 gid_t egid; 886 887 for (i = 0; i < sockets_alloc; i++) 888 switch (sockets[i].type) { 889 case AUTH_UNUSED: 890 break; 891 case AUTH_SOCKET: 892 if (FD_ISSET(sockets[i].fd, readset)) { 893 slen = sizeof(sunaddr); 894 sock = accept(sockets[i].fd, 895 (struct sockaddr *) &sunaddr, &slen); 896 if (sock < 0) { 897 error("accept from AUTH_SOCKET: %s", 898 strerror(errno)); 899 break; 900 } 901 if (getpeereid(sock, &euid, &egid) < 0) { 902 error("getpeereid %d failed: %s", 903 sock, strerror(errno)); 904 close(sock); 905 break; 906 } 907 if ((euid != 0) && (getuid() != euid)) { 908 error("uid mismatch: " 909 "peer euid %u != uid %u", 910 (u_int) euid, (u_int) getuid()); 911 close(sock); 912 break; 913 } 914 new_socket(AUTH_CONNECTION, sock); 915 } 916 break; 917 case AUTH_CONNECTION: 918 if (buffer_len(&sockets[i].output) > 0 && 919 FD_ISSET(sockets[i].fd, writeset)) { 920 do { 921 len = write(sockets[i].fd, 922 buffer_ptr(&sockets[i].output), 923 buffer_len(&sockets[i].output)); 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_consume(&sockets[i].output, len); 934 } 935 if (FD_ISSET(sockets[i].fd, readset)) { 936 do { 937 len = read(sockets[i].fd, buf, sizeof(buf)); 938 if (len == -1 && (errno == EAGAIN || 939 errno == EINTR)) 940 continue; 941 break; 942 } while (1); 943 if (len <= 0) { 944 close_socket(&sockets[i]); 945 break; 946 } 947 buffer_append(&sockets[i].input, buf, len); 948 process_message(&sockets[i]); 949 } 950 break; 951 default: 952 fatal("Unknown type %d", sockets[i].type); 953 } 954 } 955 956 static void 957 cleanup_socket(void) 958 { 959 if (socket_name[0]) 960 unlink(socket_name); 961 if (socket_dir[0]) 962 rmdir(socket_dir); 963 } 964 965 void 966 cleanup_exit(int i) 967 { 968 cleanup_socket(); 969 _exit(i); 970 } 971 972 static void 973 cleanup_handler(int sig) 974 { 975 cleanup_socket(); 976 _exit(2); 977 } 978 979 static void 980 check_parent_exists(int sig) 981 { 982 int save_errno = errno; 983 984 if (parent_pid != -1 && kill(parent_pid, 0) < 0) { 985 /* printf("Parent has died - Authentication agent exiting.\n"); */ 986 cleanup_handler(sig); /* safe */ 987 } 988 mysignal(SIGALRM, check_parent_exists); 989 alarm(10); 990 errno = save_errno; 991 } 992 993 static void 994 usage(void) 995 { 996 fprintf(stderr, "Usage: %s [options] [command [args ...]]\n", 997 __progname); 998 fprintf(stderr, "Options:\n"); 999 fprintf(stderr, " -c Generate C-shell commands on stdout.\n"); 1000 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n"); 1001 fprintf(stderr, " -k Kill the current agent.\n"); 1002 fprintf(stderr, " -d Debug mode.\n"); 1003 fprintf(stderr, " -a socket Bind agent socket to given name.\n"); 1004 fprintf(stderr, " -t life Default identity lifetime (seconds).\n"); 1005 exit(1); 1006 } 1007 1008 int 1009 main(int ac, char **av) 1010 { 1011 int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0; 1012 int sock, fd, ch, nalloc; 1013 char *shell, *format, *pidstr, *agentsocket = NULL; 1014 fd_set *readsetp = NULL, *writesetp = NULL; 1015 struct sockaddr_un sunaddr; 1016 #ifdef HAVE_SETRLIMIT 1017 struct rlimit rlim; 1018 #endif 1019 #ifdef HAVE_CYGWIN 1020 int prev_mask; 1021 #endif 1022 extern int optind; 1023 extern char *optarg; 1024 pid_t pid; 1025 char pidstrbuf[1 + 3 * sizeof pid]; 1026 1027 /* drop */ 1028 setegid(getgid()); 1029 setgid(getgid()); 1030 setuid(geteuid()); 1031 1032 #if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE) 1033 /* Disable ptrace on Linux without sgid bit */ 1034 prctl(PR_SET_DUMPABLE, 0); 1035 #endif 1036 1037 SSLeay_add_all_algorithms(); 1038 1039 __progname = ssh_get_progname(av[0]); 1040 init_rng(); 1041 seed_rng(); 1042 1043 while ((ch = getopt(ac, av, "cdksa:t:")) != -1) { 1044 switch (ch) { 1045 case 'c': 1046 if (s_flag) 1047 usage(); 1048 c_flag++; 1049 break; 1050 case 'k': 1051 k_flag++; 1052 break; 1053 case 's': 1054 if (c_flag) 1055 usage(); 1056 s_flag++; 1057 break; 1058 case 'd': 1059 if (d_flag) 1060 usage(); 1061 d_flag++; 1062 break; 1063 case 'a': 1064 agentsocket = optarg; 1065 break; 1066 case 't': 1067 if ((lifetime = convtime(optarg)) == -1) { 1068 fprintf(stderr, "Invalid lifetime\n"); 1069 usage(); 1070 } 1071 break; 1072 default: 1073 usage(); 1074 } 1075 } 1076 ac -= optind; 1077 av += optind; 1078 1079 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag)) 1080 usage(); 1081 1082 if (ac == 0 && !c_flag && !s_flag) { 1083 shell = getenv("SHELL"); 1084 if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0) 1085 c_flag = 1; 1086 } 1087 if (k_flag) { 1088 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1089 if (pidstr == NULL) { 1090 fprintf(stderr, "%s not set, cannot kill agent\n", 1091 SSH_AGENTPID_ENV_NAME); 1092 exit(1); 1093 } 1094 pid = atoi(pidstr); 1095 if (pid < 1) { 1096 fprintf(stderr, "%s=\"%s\", which is not a good PID\n", 1097 SSH_AGENTPID_ENV_NAME, pidstr); 1098 exit(1); 1099 } 1100 if (kill(pid, SIGTERM) == -1) { 1101 perror("kill"); 1102 exit(1); 1103 } 1104 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 1105 printf(format, SSH_AUTHSOCKET_ENV_NAME); 1106 printf(format, SSH_AGENTPID_ENV_NAME); 1107 printf("echo Agent pid %ld killed;\n", (long)pid); 1108 exit(0); 1109 } 1110 parent_pid = getpid(); 1111 1112 if (agentsocket == NULL) { 1113 /* Create private directory for agent socket */ 1114 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXXXX", sizeof socket_dir); 1115 if (mkdtemp(socket_dir) == NULL) { 1116 perror("mkdtemp: private socket dir"); 1117 exit(1); 1118 } 1119 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1120 (long)parent_pid); 1121 } else { 1122 /* Try to use specified agent socket */ 1123 socket_dir[0] = '\0'; 1124 strlcpy(socket_name, agentsocket, sizeof socket_name); 1125 } 1126 1127 /* 1128 * Create socket early so it will exist before command gets run from 1129 * the parent. 1130 */ 1131 sock = socket(AF_UNIX, SOCK_STREAM, 0); 1132 if (sock < 0) { 1133 perror("socket"); 1134 cleanup_exit(1); 1135 } 1136 memset(&sunaddr, 0, sizeof(sunaddr)); 1137 sunaddr.sun_family = AF_UNIX; 1138 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); 1139 #ifdef HAVE_CYGWIN 1140 prev_mask = umask(0177); 1141 #endif 1142 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) { 1143 perror("bind"); 1144 #ifdef HAVE_CYGWIN 1145 umask(prev_mask); 1146 #endif 1147 cleanup_exit(1); 1148 } 1149 #ifdef HAVE_CYGWIN 1150 umask(prev_mask); 1151 #endif 1152 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 1153 perror("listen"); 1154 cleanup_exit(1); 1155 } 1156 1157 /* 1158 * Fork, and have the parent execute the command, if any, or present 1159 * the socket data. The child continues as the authentication agent. 1160 */ 1161 if (d_flag) { 1162 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1); 1163 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1164 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1165 SSH_AUTHSOCKET_ENV_NAME); 1166 printf("echo Agent pid %ld;\n", (long)parent_pid); 1167 goto skip; 1168 } 1169 pid = fork(); 1170 if (pid == -1) { 1171 perror("fork"); 1172 cleanup_exit(1); 1173 } 1174 if (pid != 0) { /* Parent - execute the given command. */ 1175 close(sock); 1176 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1177 if (ac == 0) { 1178 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1179 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1180 SSH_AUTHSOCKET_ENV_NAME); 1181 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 1182 SSH_AGENTPID_ENV_NAME); 1183 printf("echo Agent pid %ld;\n", (long)pid); 1184 exit(0); 1185 } 1186 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1187 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1188 perror("setenv"); 1189 exit(1); 1190 } 1191 execvp(av[0], av); 1192 perror(av[0]); 1193 exit(1); 1194 } 1195 /* child */ 1196 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1197 1198 if (setsid() == -1) { 1199 error("setsid: %s", strerror(errno)); 1200 cleanup_exit(1); 1201 } 1202 1203 (void)chdir("/"); 1204 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1205 /* XXX might close listen socket */ 1206 (void)dup2(fd, STDIN_FILENO); 1207 (void)dup2(fd, STDOUT_FILENO); 1208 (void)dup2(fd, STDERR_FILENO); 1209 if (fd > 2) 1210 close(fd); 1211 } 1212 1213 #ifdef HAVE_SETRLIMIT 1214 /* deny core dumps, since memory contains unencrypted private keys */ 1215 rlim.rlim_cur = rlim.rlim_max = 0; 1216 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 1217 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1218 cleanup_exit(1); 1219 } 1220 #endif 1221 1222 skip: 1223 new_socket(AUTH_SOCKET, sock); 1224 if (ac > 0) { 1225 mysignal(SIGALRM, check_parent_exists); 1226 alarm(10); 1227 } 1228 idtab_init(); 1229 if (!d_flag) 1230 signal(SIGINT, SIG_IGN); 1231 signal(SIGPIPE, SIG_IGN); 1232 signal(SIGHUP, cleanup_handler); 1233 signal(SIGTERM, cleanup_handler); 1234 nalloc = 0; 1235 1236 while (1) { 1237 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc); 1238 if (select(max_fd + 1, readsetp, writesetp, NULL, NULL) < 0) { 1239 if (errno == EINTR) 1240 continue; 1241 fatal("select: %s", strerror(errno)); 1242 } 1243 after_select(readsetp, writesetp); 1244 } 1245 /* NOTREACHED */ 1246 } 1247