1 /* $OpenBSD: ssh-agent.c,v 1.165 2010/02/26 20:29:54 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * The authentication agent program. 7 * 8 * As far as I am concerned, the code I have written for this software 9 * can be used freely for any purpose. Any derived versions of this 10 * software must be clearly marked as such, and if the derived work is 11 * incompatible with the protocol description in the RFC file, it must be 12 * called by a name other than "ssh" or "Secure Shell". 13 * 14 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 15 * 16 * Redistribution and use in source and binary forms, with or without 17 * modification, are permitted provided that the following conditions 18 * are met: 19 * 1. Redistributions of source code must retain the above copyright 20 * notice, this list of conditions and the following disclaimer. 21 * 2. Redistributions in binary form must reproduce the above copyright 22 * notice, this list of conditions and the following disclaimer in the 23 * documentation and/or other materials provided with the distribution. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 26 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 27 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 28 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 29 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 30 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 31 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 34 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 35 */ 36 37 #include "includes.h" 38 __RCSID("$FreeBSD$"); 39 40 #include <sys/types.h> 41 #include <sys/param.h> 42 #include <sys/resource.h> 43 #include <sys/stat.h> 44 #include <sys/socket.h> 45 #ifdef HAVE_SYS_TIME_H 46 # include <sys/time.h> 47 #endif 48 #ifdef HAVE_SYS_UN_H 49 # include <sys/un.h> 50 #endif 51 #include "openbsd-compat/sys-queue.h" 52 53 #include <openssl/evp.h> 54 #include <openssl/md5.h> 55 #include "openbsd-compat/openssl-compat.h" 56 57 #include <errno.h> 58 #include <fcntl.h> 59 #ifdef HAVE_PATHS_H 60 # include <paths.h> 61 #endif 62 #include <signal.h> 63 #include <stdarg.h> 64 #include <stdio.h> 65 #include <stdlib.h> 66 #include <time.h> 67 #include <string.h> 68 #include <unistd.h> 69 70 #include "xmalloc.h" 71 #include "ssh.h" 72 #include "rsa.h" 73 #include "buffer.h" 74 #include "key.h" 75 #include "authfd.h" 76 #include "compat.h" 77 #include "log.h" 78 #include "misc.h" 79 80 #ifdef ENABLE_PKCS11 81 #include "ssh-pkcs11.h" 82 #endif 83 84 #if defined(HAVE_SYS_PRCTL_H) 85 #include <sys/prctl.h> /* For prctl() and PR_SET_DUMPABLE */ 86 #endif 87 88 typedef enum { 89 AUTH_UNUSED, 90 AUTH_SOCKET, 91 AUTH_CONNECTION 92 } sock_type; 93 94 typedef struct { 95 int fd; 96 sock_type type; 97 Buffer input; 98 Buffer output; 99 Buffer request; 100 } SocketEntry; 101 102 u_int sockets_alloc = 0; 103 SocketEntry *sockets = NULL; 104 105 typedef struct identity { 106 TAILQ_ENTRY(identity) next; 107 Key *key; 108 char *comment; 109 char *provider; 110 u_int death; 111 u_int confirm; 112 } Identity; 113 114 typedef struct { 115 int nentries; 116 TAILQ_HEAD(idqueue, identity) idlist; 117 } Idtab; 118 119 /* private key table, one per protocol version */ 120 Idtab idtable[3]; 121 122 int max_fd = 0; 123 124 /* pid of shell == parent of agent */ 125 pid_t parent_pid = -1; 126 u_int parent_alive_interval = 0; 127 128 /* pathname and directory for AUTH_SOCKET */ 129 char socket_name[MAXPATHLEN]; 130 char socket_dir[MAXPATHLEN]; 131 132 /* locking */ 133 int locked = 0; 134 char *lock_passwd = NULL; 135 136 extern char *__progname; 137 138 /* Default lifetime (0 == forever) */ 139 static int lifetime = 0; 140 141 static void 142 close_socket(SocketEntry *e) 143 { 144 close(e->fd); 145 e->fd = -1; 146 e->type = AUTH_UNUSED; 147 buffer_free(&e->input); 148 buffer_free(&e->output); 149 buffer_free(&e->request); 150 } 151 152 static void 153 idtab_init(void) 154 { 155 int i; 156 157 for (i = 0; i <=2; i++) { 158 TAILQ_INIT(&idtable[i].idlist); 159 idtable[i].nentries = 0; 160 } 161 } 162 163 /* return private key table for requested protocol version */ 164 static Idtab * 165 idtab_lookup(int version) 166 { 167 if (version < 1 || version > 2) 168 fatal("internal error, bad protocol version %d", version); 169 return &idtable[version]; 170 } 171 172 static void 173 free_identity(Identity *id) 174 { 175 key_free(id->key); 176 if (id->provider != NULL) 177 xfree(id->provider); 178 xfree(id->comment); 179 xfree(id); 180 } 181 182 /* return matching private key for given public key */ 183 static Identity * 184 lookup_identity(Key *key, int version) 185 { 186 Identity *id; 187 188 Idtab *tab = idtab_lookup(version); 189 TAILQ_FOREACH(id, &tab->idlist, next) { 190 if (key_equal(key, id->key)) 191 return (id); 192 } 193 return (NULL); 194 } 195 196 /* Check confirmation of keysign request */ 197 static int 198 confirm_key(Identity *id) 199 { 200 char *p; 201 int ret = -1; 202 203 p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX); 204 if (ask_permission("Allow use of key %s?\nKey fingerprint %s.", 205 id->comment, p)) 206 ret = 0; 207 xfree(p); 208 209 return (ret); 210 } 211 212 /* send list of supported public keys to 'client' */ 213 static void 214 process_request_identities(SocketEntry *e, int version) 215 { 216 Idtab *tab = idtab_lookup(version); 217 Identity *id; 218 Buffer msg; 219 220 buffer_init(&msg); 221 buffer_put_char(&msg, (version == 1) ? 222 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 223 buffer_put_int(&msg, tab->nentries); 224 TAILQ_FOREACH(id, &tab->idlist, next) { 225 if (id->key->type == KEY_RSA1) { 226 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n)); 227 buffer_put_bignum(&msg, id->key->rsa->e); 228 buffer_put_bignum(&msg, id->key->rsa->n); 229 } else { 230 u_char *blob; 231 u_int blen; 232 key_to_blob(id->key, &blob, &blen); 233 buffer_put_string(&msg, blob, blen); 234 xfree(blob); 235 } 236 buffer_put_cstring(&msg, id->comment); 237 } 238 buffer_put_int(&e->output, buffer_len(&msg)); 239 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 240 buffer_free(&msg); 241 } 242 243 /* ssh1 only */ 244 static void 245 process_authentication_challenge1(SocketEntry *e) 246 { 247 u_char buf[32], mdbuf[16], session_id[16]; 248 u_int response_type; 249 BIGNUM *challenge; 250 Identity *id; 251 int i, len; 252 Buffer msg; 253 MD5_CTX md; 254 Key *key; 255 256 buffer_init(&msg); 257 key = key_new(KEY_RSA1); 258 if ((challenge = BN_new()) == NULL) 259 fatal("process_authentication_challenge1: BN_new failed"); 260 261 (void) buffer_get_int(&e->request); /* ignored */ 262 buffer_get_bignum(&e->request, key->rsa->e); 263 buffer_get_bignum(&e->request, key->rsa->n); 264 buffer_get_bignum(&e->request, challenge); 265 266 /* Only protocol 1.1 is supported */ 267 if (buffer_len(&e->request) == 0) 268 goto failure; 269 buffer_get(&e->request, session_id, 16); 270 response_type = buffer_get_int(&e->request); 271 if (response_type != 1) 272 goto failure; 273 274 id = lookup_identity(key, 1); 275 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) { 276 Key *private = id->key; 277 /* Decrypt the challenge using the private key. */ 278 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0) 279 goto failure; 280 281 /* The response is MD5 of decrypted challenge plus session id. */ 282 len = BN_num_bytes(challenge); 283 if (len <= 0 || len > 32) { 284 logit("process_authentication_challenge: bad challenge length %d", len); 285 goto failure; 286 } 287 memset(buf, 0, 32); 288 BN_bn2bin(challenge, buf + 32 - len); 289 MD5_Init(&md); 290 MD5_Update(&md, buf, 32); 291 MD5_Update(&md, session_id, 16); 292 MD5_Final(mdbuf, &md); 293 294 /* Send the response. */ 295 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE); 296 for (i = 0; i < 16; i++) 297 buffer_put_char(&msg, mdbuf[i]); 298 goto send; 299 } 300 301 failure: 302 /* Unknown identity or protocol error. Send failure. */ 303 buffer_put_char(&msg, SSH_AGENT_FAILURE); 304 send: 305 buffer_put_int(&e->output, buffer_len(&msg)); 306 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 307 key_free(key); 308 BN_clear_free(challenge); 309 buffer_free(&msg); 310 } 311 312 /* ssh2 only */ 313 static void 314 process_sign_request2(SocketEntry *e) 315 { 316 u_char *blob, *data, *signature = NULL; 317 u_int blen, dlen, slen = 0; 318 extern int datafellows; 319 int odatafellows; 320 int ok = -1, flags; 321 Buffer msg; 322 Key *key; 323 324 datafellows = 0; 325 326 blob = buffer_get_string(&e->request, &blen); 327 data = buffer_get_string(&e->request, &dlen); 328 329 flags = buffer_get_int(&e->request); 330 odatafellows = datafellows; 331 if (flags & SSH_AGENT_OLD_SIGNATURE) 332 datafellows = SSH_BUG_SIGBLOB; 333 334 key = key_from_blob(blob, blen); 335 if (key != NULL) { 336 Identity *id = lookup_identity(key, 2); 337 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) 338 ok = key_sign(id->key, &signature, &slen, data, dlen); 339 key_free(key); 340 } 341 buffer_init(&msg); 342 if (ok == 0) { 343 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); 344 buffer_put_string(&msg, signature, slen); 345 } else { 346 buffer_put_char(&msg, SSH_AGENT_FAILURE); 347 } 348 buffer_put_int(&e->output, buffer_len(&msg)); 349 buffer_append(&e->output, buffer_ptr(&msg), 350 buffer_len(&msg)); 351 buffer_free(&msg); 352 xfree(data); 353 xfree(blob); 354 if (signature != NULL) 355 xfree(signature); 356 datafellows = odatafellows; 357 } 358 359 /* shared */ 360 static void 361 process_remove_identity(SocketEntry *e, int version) 362 { 363 u_int blen, bits; 364 int success = 0; 365 Key *key = NULL; 366 u_char *blob; 367 368 switch (version) { 369 case 1: 370 key = key_new(KEY_RSA1); 371 bits = buffer_get_int(&e->request); 372 buffer_get_bignum(&e->request, key->rsa->e); 373 buffer_get_bignum(&e->request, key->rsa->n); 374 375 if (bits != key_size(key)) 376 logit("Warning: identity keysize mismatch: actual %u, announced %u", 377 key_size(key), bits); 378 break; 379 case 2: 380 blob = buffer_get_string(&e->request, &blen); 381 key = key_from_blob(blob, blen); 382 xfree(blob); 383 break; 384 } 385 if (key != NULL) { 386 Identity *id = lookup_identity(key, version); 387 if (id != NULL) { 388 /* 389 * We have this key. Free the old key. Since we 390 * don't want to leave empty slots in the middle of 391 * the array, we actually free the key there and move 392 * all the entries between the empty slot and the end 393 * of the array. 394 */ 395 Idtab *tab = idtab_lookup(version); 396 if (tab->nentries < 1) 397 fatal("process_remove_identity: " 398 "internal error: tab->nentries %d", 399 tab->nentries); 400 TAILQ_REMOVE(&tab->idlist, id, next); 401 free_identity(id); 402 tab->nentries--; 403 success = 1; 404 } 405 key_free(key); 406 } 407 buffer_put_int(&e->output, 1); 408 buffer_put_char(&e->output, 409 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 410 } 411 412 static void 413 process_remove_all_identities(SocketEntry *e, int version) 414 { 415 Idtab *tab = idtab_lookup(version); 416 Identity *id; 417 418 /* Loop over all identities and clear the keys. */ 419 for (id = TAILQ_FIRST(&tab->idlist); id; 420 id = TAILQ_FIRST(&tab->idlist)) { 421 TAILQ_REMOVE(&tab->idlist, id, next); 422 free_identity(id); 423 } 424 425 /* Mark that there are no identities. */ 426 tab->nentries = 0; 427 428 /* Send success. */ 429 buffer_put_int(&e->output, 1); 430 buffer_put_char(&e->output, SSH_AGENT_SUCCESS); 431 } 432 433 /* removes expired keys and returns number of seconds until the next expiry */ 434 static u_int 435 reaper(void) 436 { 437 u_int deadline = 0, now = time(NULL); 438 Identity *id, *nxt; 439 int version; 440 Idtab *tab; 441 442 for (version = 1; version < 3; version++) { 443 tab = idtab_lookup(version); 444 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 445 nxt = TAILQ_NEXT(id, next); 446 if (id->death == 0) 447 continue; 448 if (now >= id->death) { 449 debug("expiring key '%s'", id->comment); 450 TAILQ_REMOVE(&tab->idlist, id, next); 451 free_identity(id); 452 tab->nentries--; 453 } else 454 deadline = (deadline == 0) ? id->death : 455 MIN(deadline, id->death); 456 } 457 } 458 if (deadline == 0 || deadline <= now) 459 return 0; 460 else 461 return (deadline - now); 462 } 463 464 static void 465 process_add_identity(SocketEntry *e, int version) 466 { 467 Idtab *tab = idtab_lookup(version); 468 Identity *id; 469 int type, success = 0, death = 0, confirm = 0; 470 char *type_name, *comment; 471 Key *k = NULL; 472 u_char *cert; 473 u_int len; 474 475 switch (version) { 476 case 1: 477 k = key_new_private(KEY_RSA1); 478 (void) buffer_get_int(&e->request); /* ignored */ 479 buffer_get_bignum(&e->request, k->rsa->n); 480 buffer_get_bignum(&e->request, k->rsa->e); 481 buffer_get_bignum(&e->request, k->rsa->d); 482 buffer_get_bignum(&e->request, k->rsa->iqmp); 483 484 /* SSH and SSL have p and q swapped */ 485 buffer_get_bignum(&e->request, k->rsa->q); /* p */ 486 buffer_get_bignum(&e->request, k->rsa->p); /* q */ 487 488 /* Generate additional parameters */ 489 rsa_generate_additional_parameters(k->rsa); 490 break; 491 case 2: 492 type_name = buffer_get_string(&e->request, NULL); 493 type = key_type_from_name(type_name); 494 xfree(type_name); 495 switch (type) { 496 case KEY_DSA: 497 k = key_new_private(type); 498 buffer_get_bignum2(&e->request, k->dsa->p); 499 buffer_get_bignum2(&e->request, k->dsa->q); 500 buffer_get_bignum2(&e->request, k->dsa->g); 501 buffer_get_bignum2(&e->request, k->dsa->pub_key); 502 buffer_get_bignum2(&e->request, k->dsa->priv_key); 503 break; 504 case KEY_DSA_CERT: 505 cert = buffer_get_string(&e->request, &len); 506 if ((k = key_from_blob(cert, len)) == NULL) 507 fatal("Certificate parse failed"); 508 xfree(cert); 509 key_add_private(k); 510 buffer_get_bignum2(&e->request, k->dsa->priv_key); 511 break; 512 case KEY_RSA: 513 k = key_new_private(type); 514 buffer_get_bignum2(&e->request, k->rsa->n); 515 buffer_get_bignum2(&e->request, k->rsa->e); 516 buffer_get_bignum2(&e->request, k->rsa->d); 517 buffer_get_bignum2(&e->request, k->rsa->iqmp); 518 buffer_get_bignum2(&e->request, k->rsa->p); 519 buffer_get_bignum2(&e->request, k->rsa->q); 520 521 /* Generate additional parameters */ 522 rsa_generate_additional_parameters(k->rsa); 523 break; 524 case KEY_RSA_CERT: 525 cert = buffer_get_string(&e->request, &len); 526 if ((k = key_from_blob(cert, len)) == NULL) 527 fatal("Certificate parse failed"); 528 xfree(cert); 529 key_add_private(k); 530 buffer_get_bignum2(&e->request, k->rsa->d); 531 buffer_get_bignum2(&e->request, k->rsa->iqmp); 532 buffer_get_bignum2(&e->request, k->rsa->p); 533 buffer_get_bignum2(&e->request, k->rsa->q); 534 break; 535 default: 536 buffer_clear(&e->request); 537 goto send; 538 } 539 break; 540 } 541 /* enable blinding */ 542 switch (k->type) { 543 case KEY_RSA: 544 case KEY_RSA_CERT: 545 case KEY_RSA1: 546 if (RSA_blinding_on(k->rsa, NULL) != 1) { 547 error("process_add_identity: RSA_blinding_on failed"); 548 key_free(k); 549 goto send; 550 } 551 break; 552 } 553 comment = buffer_get_string(&e->request, NULL); 554 if (k == NULL) { 555 xfree(comment); 556 goto send; 557 } 558 while (buffer_len(&e->request)) { 559 switch ((type = buffer_get_char(&e->request))) { 560 case SSH_AGENT_CONSTRAIN_LIFETIME: 561 death = time(NULL) + buffer_get_int(&e->request); 562 break; 563 case SSH_AGENT_CONSTRAIN_CONFIRM: 564 confirm = 1; 565 break; 566 default: 567 error("process_add_identity: " 568 "Unknown constraint type %d", type); 569 xfree(comment); 570 key_free(k); 571 goto send; 572 } 573 } 574 success = 1; 575 if (lifetime && !death) 576 death = time(NULL) + lifetime; 577 if ((id = lookup_identity(k, version)) == NULL) { 578 id = xcalloc(1, sizeof(Identity)); 579 id->key = k; 580 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 581 /* Increment the number of identities. */ 582 tab->nentries++; 583 } else { 584 key_free(k); 585 xfree(id->comment); 586 } 587 id->comment = comment; 588 id->death = death; 589 id->confirm = confirm; 590 send: 591 buffer_put_int(&e->output, 1); 592 buffer_put_char(&e->output, 593 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 594 } 595 596 /* XXX todo: encrypt sensitive data with passphrase */ 597 static void 598 process_lock_agent(SocketEntry *e, int lock) 599 { 600 int success = 0; 601 char *passwd; 602 603 passwd = buffer_get_string(&e->request, NULL); 604 if (locked && !lock && strcmp(passwd, lock_passwd) == 0) { 605 locked = 0; 606 memset(lock_passwd, 0, strlen(lock_passwd)); 607 xfree(lock_passwd); 608 lock_passwd = NULL; 609 success = 1; 610 } else if (!locked && lock) { 611 locked = 1; 612 lock_passwd = xstrdup(passwd); 613 success = 1; 614 } 615 memset(passwd, 0, strlen(passwd)); 616 xfree(passwd); 617 618 buffer_put_int(&e->output, 1); 619 buffer_put_char(&e->output, 620 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 621 } 622 623 static void 624 no_identities(SocketEntry *e, u_int type) 625 { 626 Buffer msg; 627 628 buffer_init(&msg); 629 buffer_put_char(&msg, 630 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ? 631 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 632 buffer_put_int(&msg, 0); 633 buffer_put_int(&e->output, buffer_len(&msg)); 634 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 635 buffer_free(&msg); 636 } 637 638 #ifdef ENABLE_PKCS11 639 static void 640 process_add_smartcard_key(SocketEntry *e) 641 { 642 char *provider = NULL, *pin; 643 int i, type, version, count = 0, success = 0, death = 0, confirm = 0; 644 Key **keys = NULL, *k; 645 Identity *id; 646 Idtab *tab; 647 648 provider = buffer_get_string(&e->request, NULL); 649 pin = buffer_get_string(&e->request, NULL); 650 651 while (buffer_len(&e->request)) { 652 switch ((type = buffer_get_char(&e->request))) { 653 case SSH_AGENT_CONSTRAIN_LIFETIME: 654 death = time(NULL) + buffer_get_int(&e->request); 655 break; 656 case SSH_AGENT_CONSTRAIN_CONFIRM: 657 confirm = 1; 658 break; 659 default: 660 error("process_add_smartcard_key: " 661 "Unknown constraint type %d", type); 662 goto send; 663 } 664 } 665 if (lifetime && !death) 666 death = time(NULL) + lifetime; 667 668 count = pkcs11_add_provider(provider, pin, &keys); 669 for (i = 0; i < count; i++) { 670 k = keys[i]; 671 version = k->type == KEY_RSA1 ? 1 : 2; 672 tab = idtab_lookup(version); 673 if (lookup_identity(k, version) == NULL) { 674 id = xcalloc(1, sizeof(Identity)); 675 id->key = k; 676 id->provider = xstrdup(provider); 677 id->comment = xstrdup(provider); /* XXX */ 678 id->death = death; 679 id->confirm = confirm; 680 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 681 tab->nentries++; 682 success = 1; 683 } else { 684 key_free(k); 685 } 686 keys[i] = NULL; 687 } 688 send: 689 if (pin) 690 xfree(pin); 691 if (provider) 692 xfree(provider); 693 if (keys) 694 xfree(keys); 695 buffer_put_int(&e->output, 1); 696 buffer_put_char(&e->output, 697 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 698 } 699 700 static void 701 process_remove_smartcard_key(SocketEntry *e) 702 { 703 char *provider = NULL, *pin = NULL; 704 int version, success = 0; 705 Identity *id, *nxt; 706 Idtab *tab; 707 708 provider = buffer_get_string(&e->request, NULL); 709 pin = buffer_get_string(&e->request, NULL); 710 xfree(pin); 711 712 for (version = 1; version < 3; version++) { 713 tab = idtab_lookup(version); 714 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 715 nxt = TAILQ_NEXT(id, next); 716 if (!strcmp(provider, id->provider)) { 717 TAILQ_REMOVE(&tab->idlist, id, next); 718 free_identity(id); 719 tab->nentries--; 720 } 721 } 722 } 723 if (pkcs11_del_provider(provider) == 0) 724 success = 1; 725 else 726 error("process_remove_smartcard_key:" 727 " pkcs11_del_provider failed"); 728 xfree(provider); 729 buffer_put_int(&e->output, 1); 730 buffer_put_char(&e->output, 731 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 732 } 733 #endif /* ENABLE_PKCS11 */ 734 735 /* dispatch incoming messages */ 736 737 static void 738 process_message(SocketEntry *e) 739 { 740 u_int msg_len, type; 741 u_char *cp; 742 743 if (buffer_len(&e->input) < 5) 744 return; /* Incomplete message. */ 745 cp = buffer_ptr(&e->input); 746 msg_len = get_u32(cp); 747 if (msg_len > 256 * 1024) { 748 close_socket(e); 749 return; 750 } 751 if (buffer_len(&e->input) < msg_len + 4) 752 return; 753 754 /* move the current input to e->request */ 755 buffer_consume(&e->input, 4); 756 buffer_clear(&e->request); 757 buffer_append(&e->request, buffer_ptr(&e->input), msg_len); 758 buffer_consume(&e->input, msg_len); 759 type = buffer_get_char(&e->request); 760 761 /* check wheter agent is locked */ 762 if (locked && type != SSH_AGENTC_UNLOCK) { 763 buffer_clear(&e->request); 764 switch (type) { 765 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 766 case SSH2_AGENTC_REQUEST_IDENTITIES: 767 /* send empty lists */ 768 no_identities(e, type); 769 break; 770 default: 771 /* send a fail message for all other request types */ 772 buffer_put_int(&e->output, 1); 773 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 774 } 775 return; 776 } 777 778 debug("type %d", type); 779 switch (type) { 780 case SSH_AGENTC_LOCK: 781 case SSH_AGENTC_UNLOCK: 782 process_lock_agent(e, type == SSH_AGENTC_LOCK); 783 break; 784 /* ssh1 */ 785 case SSH_AGENTC_RSA_CHALLENGE: 786 process_authentication_challenge1(e); 787 break; 788 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 789 process_request_identities(e, 1); 790 break; 791 case SSH_AGENTC_ADD_RSA_IDENTITY: 792 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 793 process_add_identity(e, 1); 794 break; 795 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 796 process_remove_identity(e, 1); 797 break; 798 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 799 process_remove_all_identities(e, 1); 800 break; 801 /* ssh2 */ 802 case SSH2_AGENTC_SIGN_REQUEST: 803 process_sign_request2(e); 804 break; 805 case SSH2_AGENTC_REQUEST_IDENTITIES: 806 process_request_identities(e, 2); 807 break; 808 case SSH2_AGENTC_ADD_IDENTITY: 809 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 810 process_add_identity(e, 2); 811 break; 812 case SSH2_AGENTC_REMOVE_IDENTITY: 813 process_remove_identity(e, 2); 814 break; 815 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 816 process_remove_all_identities(e, 2); 817 break; 818 #ifdef ENABLE_PKCS11 819 case SSH_AGENTC_ADD_SMARTCARD_KEY: 820 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 821 process_add_smartcard_key(e); 822 break; 823 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 824 process_remove_smartcard_key(e); 825 break; 826 #endif /* ENABLE_PKCS11 */ 827 default: 828 /* Unknown message. Respond with failure. */ 829 error("Unknown message %d", type); 830 buffer_clear(&e->request); 831 buffer_put_int(&e->output, 1); 832 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 833 break; 834 } 835 } 836 837 static void 838 new_socket(sock_type type, int fd) 839 { 840 u_int i, old_alloc, new_alloc; 841 842 set_nonblock(fd); 843 844 if (fd > max_fd) 845 max_fd = fd; 846 847 for (i = 0; i < sockets_alloc; i++) 848 if (sockets[i].type == AUTH_UNUSED) { 849 sockets[i].fd = fd; 850 buffer_init(&sockets[i].input); 851 buffer_init(&sockets[i].output); 852 buffer_init(&sockets[i].request); 853 sockets[i].type = type; 854 return; 855 } 856 old_alloc = sockets_alloc; 857 new_alloc = sockets_alloc + 10; 858 sockets = xrealloc(sockets, new_alloc, sizeof(sockets[0])); 859 for (i = old_alloc; i < new_alloc; i++) 860 sockets[i].type = AUTH_UNUSED; 861 sockets_alloc = new_alloc; 862 sockets[old_alloc].fd = fd; 863 buffer_init(&sockets[old_alloc].input); 864 buffer_init(&sockets[old_alloc].output); 865 buffer_init(&sockets[old_alloc].request); 866 sockets[old_alloc].type = type; 867 } 868 869 static int 870 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp, 871 struct timeval **tvpp) 872 { 873 u_int i, sz, deadline; 874 int n = 0; 875 static struct timeval tv; 876 877 for (i = 0; i < sockets_alloc; i++) { 878 switch (sockets[i].type) { 879 case AUTH_SOCKET: 880 case AUTH_CONNECTION: 881 n = MAX(n, sockets[i].fd); 882 break; 883 case AUTH_UNUSED: 884 break; 885 default: 886 fatal("Unknown socket type %d", sockets[i].type); 887 break; 888 } 889 } 890 891 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 892 if (*fdrp == NULL || sz > *nallocp) { 893 if (*fdrp) 894 xfree(*fdrp); 895 if (*fdwp) 896 xfree(*fdwp); 897 *fdrp = xmalloc(sz); 898 *fdwp = xmalloc(sz); 899 *nallocp = sz; 900 } 901 if (n < *fdl) 902 debug("XXX shrink: %d < %d", n, *fdl); 903 *fdl = n; 904 memset(*fdrp, 0, sz); 905 memset(*fdwp, 0, sz); 906 907 for (i = 0; i < sockets_alloc; i++) { 908 switch (sockets[i].type) { 909 case AUTH_SOCKET: 910 case AUTH_CONNECTION: 911 FD_SET(sockets[i].fd, *fdrp); 912 if (buffer_len(&sockets[i].output) > 0) 913 FD_SET(sockets[i].fd, *fdwp); 914 break; 915 default: 916 break; 917 } 918 } 919 deadline = reaper(); 920 if (parent_alive_interval != 0) 921 deadline = (deadline == 0) ? parent_alive_interval : 922 MIN(deadline, parent_alive_interval); 923 if (deadline == 0) { 924 *tvpp = NULL; 925 } else { 926 tv.tv_sec = deadline; 927 tv.tv_usec = 0; 928 *tvpp = &tv; 929 } 930 return (1); 931 } 932 933 static void 934 after_select(fd_set *readset, fd_set *writeset) 935 { 936 struct sockaddr_un sunaddr; 937 socklen_t slen; 938 char buf[1024]; 939 int len, sock; 940 u_int i, orig_alloc; 941 uid_t euid; 942 gid_t egid; 943 944 for (i = 0, orig_alloc = sockets_alloc; i < orig_alloc; i++) 945 switch (sockets[i].type) { 946 case AUTH_UNUSED: 947 break; 948 case AUTH_SOCKET: 949 if (FD_ISSET(sockets[i].fd, readset)) { 950 slen = sizeof(sunaddr); 951 sock = accept(sockets[i].fd, 952 (struct sockaddr *)&sunaddr, &slen); 953 if (sock < 0) { 954 error("accept from AUTH_SOCKET: %s", 955 strerror(errno)); 956 break; 957 } 958 if (getpeereid(sock, &euid, &egid) < 0) { 959 error("getpeereid %d failed: %s", 960 sock, strerror(errno)); 961 close(sock); 962 break; 963 } 964 if ((euid != 0) && (getuid() != euid)) { 965 error("uid mismatch: " 966 "peer euid %u != uid %u", 967 (u_int) euid, (u_int) getuid()); 968 close(sock); 969 break; 970 } 971 new_socket(AUTH_CONNECTION, sock); 972 } 973 break; 974 case AUTH_CONNECTION: 975 if (buffer_len(&sockets[i].output) > 0 && 976 FD_ISSET(sockets[i].fd, writeset)) { 977 len = write(sockets[i].fd, 978 buffer_ptr(&sockets[i].output), 979 buffer_len(&sockets[i].output)); 980 if (len == -1 && (errno == EAGAIN || 981 errno == EWOULDBLOCK || 982 errno == EINTR)) 983 continue; 984 if (len <= 0) { 985 close_socket(&sockets[i]); 986 break; 987 } 988 buffer_consume(&sockets[i].output, len); 989 } 990 if (FD_ISSET(sockets[i].fd, readset)) { 991 len = read(sockets[i].fd, buf, sizeof(buf)); 992 if (len == -1 && (errno == EAGAIN || 993 errno == EWOULDBLOCK || 994 errno == EINTR)) 995 continue; 996 if (len <= 0) { 997 close_socket(&sockets[i]); 998 break; 999 } 1000 buffer_append(&sockets[i].input, buf, len); 1001 process_message(&sockets[i]); 1002 } 1003 break; 1004 default: 1005 fatal("Unknown type %d", sockets[i].type); 1006 } 1007 } 1008 1009 static void 1010 cleanup_socket(void) 1011 { 1012 if (socket_name[0]) 1013 unlink(socket_name); 1014 if (socket_dir[0]) 1015 rmdir(socket_dir); 1016 } 1017 1018 void 1019 cleanup_exit(int i) 1020 { 1021 cleanup_socket(); 1022 _exit(i); 1023 } 1024 1025 /*ARGSUSED*/ 1026 static void 1027 cleanup_handler(int sig) 1028 { 1029 cleanup_socket(); 1030 #ifdef ENABLE_PKCS11 1031 pkcs11_terminate(); 1032 #endif 1033 _exit(2); 1034 } 1035 1036 static void 1037 check_parent_exists(void) 1038 { 1039 if (parent_pid != -1 && kill(parent_pid, 0) < 0) { 1040 /* printf("Parent has died - Authentication agent exiting.\n"); */ 1041 cleanup_socket(); 1042 _exit(2); 1043 } 1044 } 1045 1046 static void 1047 usage(void) 1048 { 1049 fprintf(stderr, "usage: %s [options] [command [arg ...]]\n", 1050 __progname); 1051 fprintf(stderr, "Options:\n"); 1052 fprintf(stderr, " -c Generate C-shell commands on stdout.\n"); 1053 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n"); 1054 fprintf(stderr, " -k Kill the current agent.\n"); 1055 fprintf(stderr, " -d Debug mode.\n"); 1056 fprintf(stderr, " -a socket Bind agent socket to given name.\n"); 1057 fprintf(stderr, " -t life Default identity lifetime (seconds).\n"); 1058 exit(1); 1059 } 1060 1061 int 1062 main(int ac, char **av) 1063 { 1064 int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0; 1065 int sock, fd, ch, result, saved_errno; 1066 u_int nalloc; 1067 char *shell, *format, *pidstr, *agentsocket = NULL; 1068 fd_set *readsetp = NULL, *writesetp = NULL; 1069 struct sockaddr_un sunaddr; 1070 #ifdef HAVE_SETRLIMIT 1071 struct rlimit rlim; 1072 #endif 1073 int prev_mask; 1074 extern int optind; 1075 extern char *optarg; 1076 pid_t pid; 1077 char pidstrbuf[1 + 3 * sizeof pid]; 1078 struct timeval *tvp = NULL; 1079 size_t len; 1080 1081 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1082 sanitise_stdfd(); 1083 1084 /* drop */ 1085 setegid(getgid()); 1086 setgid(getgid()); 1087 setuid(geteuid()); 1088 1089 #if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE) 1090 /* Disable ptrace on Linux without sgid bit */ 1091 prctl(PR_SET_DUMPABLE, 0); 1092 #endif 1093 1094 SSLeay_add_all_algorithms(); 1095 1096 __progname = ssh_get_progname(av[0]); 1097 init_rng(); 1098 seed_rng(); 1099 1100 while ((ch = getopt(ac, av, "cdksa:t:")) != -1) { 1101 switch (ch) { 1102 case 'c': 1103 if (s_flag) 1104 usage(); 1105 c_flag++; 1106 break; 1107 case 'k': 1108 k_flag++; 1109 break; 1110 case 's': 1111 if (c_flag) 1112 usage(); 1113 s_flag++; 1114 break; 1115 case 'd': 1116 if (d_flag) 1117 usage(); 1118 d_flag++; 1119 break; 1120 case 'a': 1121 agentsocket = optarg; 1122 break; 1123 case 't': 1124 if ((lifetime = convtime(optarg)) == -1) { 1125 fprintf(stderr, "Invalid lifetime\n"); 1126 usage(); 1127 } 1128 break; 1129 default: 1130 usage(); 1131 } 1132 } 1133 ac -= optind; 1134 av += optind; 1135 1136 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag)) 1137 usage(); 1138 1139 if (ac == 0 && !c_flag && !s_flag) { 1140 shell = getenv("SHELL"); 1141 if (shell != NULL && (len = strlen(shell)) > 2 && 1142 strncmp(shell + len - 3, "csh", 3) == 0) 1143 c_flag = 1; 1144 } 1145 if (k_flag) { 1146 const char *errstr = NULL; 1147 1148 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1149 if (pidstr == NULL) { 1150 fprintf(stderr, "%s not set, cannot kill agent\n", 1151 SSH_AGENTPID_ENV_NAME); 1152 exit(1); 1153 } 1154 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr); 1155 if (errstr) { 1156 fprintf(stderr, 1157 "%s=\"%s\", which is not a good PID: %s\n", 1158 SSH_AGENTPID_ENV_NAME, pidstr, errstr); 1159 exit(1); 1160 } 1161 if (kill(pid, SIGTERM) == -1) { 1162 perror("kill"); 1163 exit(1); 1164 } 1165 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 1166 printf(format, SSH_AUTHSOCKET_ENV_NAME); 1167 printf(format, SSH_AGENTPID_ENV_NAME); 1168 printf("echo Agent pid %ld killed;\n", (long)pid); 1169 exit(0); 1170 } 1171 parent_pid = getpid(); 1172 1173 if (agentsocket == NULL) { 1174 /* Create private directory for agent socket */ 1175 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXXXX", sizeof socket_dir); 1176 if (mkdtemp(socket_dir) == NULL) { 1177 perror("mkdtemp: private socket dir"); 1178 exit(1); 1179 } 1180 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1181 (long)parent_pid); 1182 } else { 1183 /* Try to use specified agent socket */ 1184 socket_dir[0] = '\0'; 1185 strlcpy(socket_name, agentsocket, sizeof socket_name); 1186 } 1187 1188 /* 1189 * Create socket early so it will exist before command gets run from 1190 * the parent. 1191 */ 1192 sock = socket(AF_UNIX, SOCK_STREAM, 0); 1193 if (sock < 0) { 1194 perror("socket"); 1195 *socket_name = '\0'; /* Don't unlink any existing file */ 1196 cleanup_exit(1); 1197 } 1198 memset(&sunaddr, 0, sizeof(sunaddr)); 1199 sunaddr.sun_family = AF_UNIX; 1200 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); 1201 prev_mask = umask(0177); 1202 if (bind(sock, (struct sockaddr *) &sunaddr, sizeof(sunaddr)) < 0) { 1203 perror("bind"); 1204 *socket_name = '\0'; /* Don't unlink any existing file */ 1205 umask(prev_mask); 1206 cleanup_exit(1); 1207 } 1208 umask(prev_mask); 1209 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 1210 perror("listen"); 1211 cleanup_exit(1); 1212 } 1213 1214 /* 1215 * Fork, and have the parent execute the command, if any, or present 1216 * the socket data. The child continues as the authentication agent. 1217 */ 1218 if (d_flag) { 1219 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1); 1220 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1221 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1222 SSH_AUTHSOCKET_ENV_NAME); 1223 printf("echo Agent pid %ld;\n", (long)parent_pid); 1224 goto skip; 1225 } 1226 pid = fork(); 1227 if (pid == -1) { 1228 perror("fork"); 1229 cleanup_exit(1); 1230 } 1231 if (pid != 0) { /* Parent - execute the given command. */ 1232 close(sock); 1233 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1234 if (ac == 0) { 1235 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1236 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1237 SSH_AUTHSOCKET_ENV_NAME); 1238 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 1239 SSH_AGENTPID_ENV_NAME); 1240 printf("echo Agent pid %ld;\n", (long)pid); 1241 exit(0); 1242 } 1243 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1244 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1245 perror("setenv"); 1246 exit(1); 1247 } 1248 execvp(av[0], av); 1249 perror(av[0]); 1250 exit(1); 1251 } 1252 /* child */ 1253 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1254 1255 if (setsid() == -1) { 1256 error("setsid: %s", strerror(errno)); 1257 cleanup_exit(1); 1258 } 1259 1260 (void)chdir("/"); 1261 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1262 /* XXX might close listen socket */ 1263 (void)dup2(fd, STDIN_FILENO); 1264 (void)dup2(fd, STDOUT_FILENO); 1265 (void)dup2(fd, STDERR_FILENO); 1266 if (fd > 2) 1267 close(fd); 1268 } 1269 1270 #ifdef HAVE_SETRLIMIT 1271 /* deny core dumps, since memory contains unencrypted private keys */ 1272 rlim.rlim_cur = rlim.rlim_max = 0; 1273 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 1274 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1275 cleanup_exit(1); 1276 } 1277 #endif 1278 1279 skip: 1280 1281 #ifdef ENABLE_PKCS11 1282 pkcs11_init(0); 1283 #endif 1284 new_socket(AUTH_SOCKET, sock); 1285 if (ac > 0) 1286 parent_alive_interval = 10; 1287 idtab_init(); 1288 if (!d_flag) 1289 signal(SIGINT, SIG_IGN); 1290 signal(SIGPIPE, SIG_IGN); 1291 signal(SIGHUP, cleanup_handler); 1292 signal(SIGTERM, cleanup_handler); 1293 nalloc = 0; 1294 1295 while (1) { 1296 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp); 1297 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp); 1298 saved_errno = errno; 1299 if (parent_alive_interval != 0) 1300 check_parent_exists(); 1301 (void) reaper(); /* remove expired keys */ 1302 if (result < 0) { 1303 if (saved_errno == EINTR) 1304 continue; 1305 fatal("select: %s", strerror(saved_errno)); 1306 } else if (result > 0) 1307 after_select(readsetp, writesetp); 1308 } 1309 /* NOTREACHED */ 1310 } 1311