1 /* $OpenBSD: ssh-agent.c,v 1.166 2010/04/16 01:47:26 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 39 #include <sys/types.h> 40 #include <sys/param.h> 41 #include <sys/resource.h> 42 #include <sys/stat.h> 43 #include <sys/socket.h> 44 #ifdef HAVE_SYS_TIME_H 45 # include <sys/time.h> 46 #endif 47 #ifdef HAVE_SYS_UN_H 48 # include <sys/un.h> 49 #endif 50 #include "openbsd-compat/sys-queue.h" 51 52 #include <openssl/evp.h> 53 #include <openssl/md5.h> 54 #include "openbsd-compat/openssl-compat.h" 55 56 #include <errno.h> 57 #include <fcntl.h> 58 #ifdef HAVE_PATHS_H 59 # include <paths.h> 60 #endif 61 #include <signal.h> 62 #include <stdarg.h> 63 #include <stdio.h> 64 #include <stdlib.h> 65 #include <time.h> 66 #include <string.h> 67 #include <unistd.h> 68 69 #include "xmalloc.h" 70 #include "ssh.h" 71 #include "rsa.h" 72 #include "buffer.h" 73 #include "key.h" 74 #include "authfd.h" 75 #include "compat.h" 76 #include "log.h" 77 #include "misc.h" 78 79 #ifdef ENABLE_PKCS11 80 #include "ssh-pkcs11.h" 81 #endif 82 83 #if defined(HAVE_SYS_PRCTL_H) 84 #include <sys/prctl.h> /* For prctl() and PR_SET_DUMPABLE */ 85 #endif 86 87 typedef enum { 88 AUTH_UNUSED, 89 AUTH_SOCKET, 90 AUTH_CONNECTION 91 } sock_type; 92 93 typedef struct { 94 int fd; 95 sock_type type; 96 Buffer input; 97 Buffer output; 98 Buffer request; 99 } SocketEntry; 100 101 u_int sockets_alloc = 0; 102 SocketEntry *sockets = NULL; 103 104 typedef struct identity { 105 TAILQ_ENTRY(identity) next; 106 Key *key; 107 char *comment; 108 char *provider; 109 u_int death; 110 u_int confirm; 111 } Identity; 112 113 typedef struct { 114 int nentries; 115 TAILQ_HEAD(idqueue, identity) idlist; 116 } Idtab; 117 118 /* private key table, one per protocol version */ 119 Idtab idtable[3]; 120 121 int max_fd = 0; 122 123 /* pid of shell == parent of agent */ 124 pid_t parent_pid = -1; 125 u_int parent_alive_interval = 0; 126 127 /* pathname and directory for AUTH_SOCKET */ 128 char socket_name[MAXPATHLEN]; 129 char socket_dir[MAXPATHLEN]; 130 131 /* locking */ 132 int locked = 0; 133 char *lock_passwd = NULL; 134 135 extern char *__progname; 136 137 /* Default lifetime (0 == forever) */ 138 static int lifetime = 0; 139 140 static void 141 close_socket(SocketEntry *e) 142 { 143 close(e->fd); 144 e->fd = -1; 145 e->type = AUTH_UNUSED; 146 buffer_free(&e->input); 147 buffer_free(&e->output); 148 buffer_free(&e->request); 149 } 150 151 static void 152 idtab_init(void) 153 { 154 int i; 155 156 for (i = 0; i <=2; i++) { 157 TAILQ_INIT(&idtable[i].idlist); 158 idtable[i].nentries = 0; 159 } 160 } 161 162 /* return private key table for requested protocol version */ 163 static Idtab * 164 idtab_lookup(int version) 165 { 166 if (version < 1 || version > 2) 167 fatal("internal error, bad protocol version %d", version); 168 return &idtable[version]; 169 } 170 171 static void 172 free_identity(Identity *id) 173 { 174 key_free(id->key); 175 if (id->provider != NULL) 176 xfree(id->provider); 177 xfree(id->comment); 178 xfree(id); 179 } 180 181 /* return matching private key for given public key */ 182 static Identity * 183 lookup_identity(Key *key, int version) 184 { 185 Identity *id; 186 187 Idtab *tab = idtab_lookup(version); 188 TAILQ_FOREACH(id, &tab->idlist, next) { 189 if (key_equal(key, id->key)) 190 return (id); 191 } 192 return (NULL); 193 } 194 195 /* Check confirmation of keysign request */ 196 static int 197 confirm_key(Identity *id) 198 { 199 char *p; 200 int ret = -1; 201 202 p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX); 203 if (ask_permission("Allow use of key %s?\nKey fingerprint %s.", 204 id->comment, p)) 205 ret = 0; 206 xfree(p); 207 208 return (ret); 209 } 210 211 /* send list of supported public keys to 'client' */ 212 static void 213 process_request_identities(SocketEntry *e, int version) 214 { 215 Idtab *tab = idtab_lookup(version); 216 Identity *id; 217 Buffer msg; 218 219 buffer_init(&msg); 220 buffer_put_char(&msg, (version == 1) ? 221 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 222 buffer_put_int(&msg, tab->nentries); 223 TAILQ_FOREACH(id, &tab->idlist, next) { 224 if (id->key->type == KEY_RSA1) { 225 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n)); 226 buffer_put_bignum(&msg, id->key->rsa->e); 227 buffer_put_bignum(&msg, id->key->rsa->n); 228 } else { 229 u_char *blob; 230 u_int blen; 231 key_to_blob(id->key, &blob, &blen); 232 buffer_put_string(&msg, blob, blen); 233 xfree(blob); 234 } 235 buffer_put_cstring(&msg, id->comment); 236 } 237 buffer_put_int(&e->output, buffer_len(&msg)); 238 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 239 buffer_free(&msg); 240 } 241 242 /* ssh1 only */ 243 static void 244 process_authentication_challenge1(SocketEntry *e) 245 { 246 u_char buf[32], mdbuf[16], session_id[16]; 247 u_int response_type; 248 BIGNUM *challenge; 249 Identity *id; 250 int i, len; 251 Buffer msg; 252 MD5_CTX md; 253 Key *key; 254 255 buffer_init(&msg); 256 key = key_new(KEY_RSA1); 257 if ((challenge = BN_new()) == NULL) 258 fatal("process_authentication_challenge1: BN_new failed"); 259 260 (void) buffer_get_int(&e->request); /* ignored */ 261 buffer_get_bignum(&e->request, key->rsa->e); 262 buffer_get_bignum(&e->request, key->rsa->n); 263 buffer_get_bignum(&e->request, challenge); 264 265 /* Only protocol 1.1 is supported */ 266 if (buffer_len(&e->request) == 0) 267 goto failure; 268 buffer_get(&e->request, session_id, 16); 269 response_type = buffer_get_int(&e->request); 270 if (response_type != 1) 271 goto failure; 272 273 id = lookup_identity(key, 1); 274 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) { 275 Key *private = id->key; 276 /* Decrypt the challenge using the private key. */ 277 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0) 278 goto failure; 279 280 /* The response is MD5 of decrypted challenge plus session id. */ 281 len = BN_num_bytes(challenge); 282 if (len <= 0 || len > 32) { 283 logit("process_authentication_challenge: bad challenge length %d", len); 284 goto failure; 285 } 286 memset(buf, 0, 32); 287 BN_bn2bin(challenge, buf + 32 - len); 288 MD5_Init(&md); 289 MD5_Update(&md, buf, 32); 290 MD5_Update(&md, session_id, 16); 291 MD5_Final(mdbuf, &md); 292 293 /* Send the response. */ 294 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE); 295 for (i = 0; i < 16; i++) 296 buffer_put_char(&msg, mdbuf[i]); 297 goto send; 298 } 299 300 failure: 301 /* Unknown identity or protocol error. Send failure. */ 302 buffer_put_char(&msg, SSH_AGENT_FAILURE); 303 send: 304 buffer_put_int(&e->output, buffer_len(&msg)); 305 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 306 key_free(key); 307 BN_clear_free(challenge); 308 buffer_free(&msg); 309 } 310 311 /* ssh2 only */ 312 static void 313 process_sign_request2(SocketEntry *e) 314 { 315 u_char *blob, *data, *signature = NULL; 316 u_int blen, dlen, slen = 0; 317 extern int datafellows; 318 int odatafellows; 319 int ok = -1, flags; 320 Buffer msg; 321 Key *key; 322 323 datafellows = 0; 324 325 blob = buffer_get_string(&e->request, &blen); 326 data = buffer_get_string(&e->request, &dlen); 327 328 flags = buffer_get_int(&e->request); 329 odatafellows = datafellows; 330 if (flags & SSH_AGENT_OLD_SIGNATURE) 331 datafellows = SSH_BUG_SIGBLOB; 332 333 key = key_from_blob(blob, blen); 334 if (key != NULL) { 335 Identity *id = lookup_identity(key, 2); 336 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) 337 ok = key_sign(id->key, &signature, &slen, data, dlen); 338 key_free(key); 339 } 340 buffer_init(&msg); 341 if (ok == 0) { 342 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); 343 buffer_put_string(&msg, signature, slen); 344 } else { 345 buffer_put_char(&msg, SSH_AGENT_FAILURE); 346 } 347 buffer_put_int(&e->output, buffer_len(&msg)); 348 buffer_append(&e->output, buffer_ptr(&msg), 349 buffer_len(&msg)); 350 buffer_free(&msg); 351 xfree(data); 352 xfree(blob); 353 if (signature != NULL) 354 xfree(signature); 355 datafellows = odatafellows; 356 } 357 358 /* shared */ 359 static void 360 process_remove_identity(SocketEntry *e, int version) 361 { 362 u_int blen, bits; 363 int success = 0; 364 Key *key = NULL; 365 u_char *blob; 366 367 switch (version) { 368 case 1: 369 key = key_new(KEY_RSA1); 370 bits = buffer_get_int(&e->request); 371 buffer_get_bignum(&e->request, key->rsa->e); 372 buffer_get_bignum(&e->request, key->rsa->n); 373 374 if (bits != key_size(key)) 375 logit("Warning: identity keysize mismatch: actual %u, announced %u", 376 key_size(key), bits); 377 break; 378 case 2: 379 blob = buffer_get_string(&e->request, &blen); 380 key = key_from_blob(blob, blen); 381 xfree(blob); 382 break; 383 } 384 if (key != NULL) { 385 Identity *id = lookup_identity(key, version); 386 if (id != NULL) { 387 /* 388 * We have this key. Free the old key. Since we 389 * don't want to leave empty slots in the middle of 390 * the array, we actually free the key there and move 391 * all the entries between the empty slot and the end 392 * of the array. 393 */ 394 Idtab *tab = idtab_lookup(version); 395 if (tab->nentries < 1) 396 fatal("process_remove_identity: " 397 "internal error: tab->nentries %d", 398 tab->nentries); 399 TAILQ_REMOVE(&tab->idlist, id, next); 400 free_identity(id); 401 tab->nentries--; 402 success = 1; 403 } 404 key_free(key); 405 } 406 buffer_put_int(&e->output, 1); 407 buffer_put_char(&e->output, 408 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 409 } 410 411 static void 412 process_remove_all_identities(SocketEntry *e, int version) 413 { 414 Idtab *tab = idtab_lookup(version); 415 Identity *id; 416 417 /* Loop over all identities and clear the keys. */ 418 for (id = TAILQ_FIRST(&tab->idlist); id; 419 id = TAILQ_FIRST(&tab->idlist)) { 420 TAILQ_REMOVE(&tab->idlist, id, next); 421 free_identity(id); 422 } 423 424 /* Mark that there are no identities. */ 425 tab->nentries = 0; 426 427 /* Send success. */ 428 buffer_put_int(&e->output, 1); 429 buffer_put_char(&e->output, SSH_AGENT_SUCCESS); 430 } 431 432 /* removes expired keys and returns number of seconds until the next expiry */ 433 static u_int 434 reaper(void) 435 { 436 u_int deadline = 0, now = time(NULL); 437 Identity *id, *nxt; 438 int version; 439 Idtab *tab; 440 441 for (version = 1; version < 3; version++) { 442 tab = idtab_lookup(version); 443 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 444 nxt = TAILQ_NEXT(id, next); 445 if (id->death == 0) 446 continue; 447 if (now >= id->death) { 448 debug("expiring key '%s'", id->comment); 449 TAILQ_REMOVE(&tab->idlist, id, next); 450 free_identity(id); 451 tab->nentries--; 452 } else 453 deadline = (deadline == 0) ? id->death : 454 MIN(deadline, id->death); 455 } 456 } 457 if (deadline == 0 || deadline <= now) 458 return 0; 459 else 460 return (deadline - now); 461 } 462 463 static void 464 process_add_identity(SocketEntry *e, int version) 465 { 466 Idtab *tab = idtab_lookup(version); 467 Identity *id; 468 int type, success = 0, death = 0, confirm = 0; 469 char *type_name, *comment; 470 Key *k = NULL; 471 u_char *cert; 472 u_int len; 473 474 switch (version) { 475 case 1: 476 k = key_new_private(KEY_RSA1); 477 (void) buffer_get_int(&e->request); /* ignored */ 478 buffer_get_bignum(&e->request, k->rsa->n); 479 buffer_get_bignum(&e->request, k->rsa->e); 480 buffer_get_bignum(&e->request, k->rsa->d); 481 buffer_get_bignum(&e->request, k->rsa->iqmp); 482 483 /* SSH and SSL have p and q swapped */ 484 buffer_get_bignum(&e->request, k->rsa->q); /* p */ 485 buffer_get_bignum(&e->request, k->rsa->p); /* q */ 486 487 /* Generate additional parameters */ 488 rsa_generate_additional_parameters(k->rsa); 489 break; 490 case 2: 491 type_name = buffer_get_string(&e->request, NULL); 492 type = key_type_from_name(type_name); 493 xfree(type_name); 494 switch (type) { 495 case KEY_DSA: 496 k = key_new_private(type); 497 buffer_get_bignum2(&e->request, k->dsa->p); 498 buffer_get_bignum2(&e->request, k->dsa->q); 499 buffer_get_bignum2(&e->request, k->dsa->g); 500 buffer_get_bignum2(&e->request, k->dsa->pub_key); 501 buffer_get_bignum2(&e->request, k->dsa->priv_key); 502 break; 503 case KEY_DSA_CERT_V00: 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_V00: 525 case KEY_RSA_CERT: 526 cert = buffer_get_string(&e->request, &len); 527 if ((k = key_from_blob(cert, len)) == NULL) 528 fatal("Certificate parse failed"); 529 xfree(cert); 530 key_add_private(k); 531 buffer_get_bignum2(&e->request, k->rsa->d); 532 buffer_get_bignum2(&e->request, k->rsa->iqmp); 533 buffer_get_bignum2(&e->request, k->rsa->p); 534 buffer_get_bignum2(&e->request, k->rsa->q); 535 break; 536 default: 537 buffer_clear(&e->request); 538 goto send; 539 } 540 break; 541 } 542 /* enable blinding */ 543 switch (k->type) { 544 case KEY_RSA: 545 case KEY_RSA_CERT_V00: 546 case KEY_RSA_CERT: 547 case KEY_RSA1: 548 if (RSA_blinding_on(k->rsa, NULL) != 1) { 549 error("process_add_identity: RSA_blinding_on failed"); 550 key_free(k); 551 goto send; 552 } 553 break; 554 } 555 comment = buffer_get_string(&e->request, NULL); 556 if (k == NULL) { 557 xfree(comment); 558 goto send; 559 } 560 while (buffer_len(&e->request)) { 561 switch ((type = buffer_get_char(&e->request))) { 562 case SSH_AGENT_CONSTRAIN_LIFETIME: 563 death = time(NULL) + buffer_get_int(&e->request); 564 break; 565 case SSH_AGENT_CONSTRAIN_CONFIRM: 566 confirm = 1; 567 break; 568 default: 569 error("process_add_identity: " 570 "Unknown constraint type %d", type); 571 xfree(comment); 572 key_free(k); 573 goto send; 574 } 575 } 576 success = 1; 577 if (lifetime && !death) 578 death = time(NULL) + lifetime; 579 if ((id = lookup_identity(k, version)) == NULL) { 580 id = xcalloc(1, sizeof(Identity)); 581 id->key = k; 582 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 583 /* Increment the number of identities. */ 584 tab->nentries++; 585 } else { 586 key_free(k); 587 xfree(id->comment); 588 } 589 id->comment = comment; 590 id->death = death; 591 id->confirm = confirm; 592 send: 593 buffer_put_int(&e->output, 1); 594 buffer_put_char(&e->output, 595 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 596 } 597 598 /* XXX todo: encrypt sensitive data with passphrase */ 599 static void 600 process_lock_agent(SocketEntry *e, int lock) 601 { 602 int success = 0; 603 char *passwd; 604 605 passwd = buffer_get_string(&e->request, NULL); 606 if (locked && !lock && strcmp(passwd, lock_passwd) == 0) { 607 locked = 0; 608 memset(lock_passwd, 0, strlen(lock_passwd)); 609 xfree(lock_passwd); 610 lock_passwd = NULL; 611 success = 1; 612 } else if (!locked && lock) { 613 locked = 1; 614 lock_passwd = xstrdup(passwd); 615 success = 1; 616 } 617 memset(passwd, 0, strlen(passwd)); 618 xfree(passwd); 619 620 buffer_put_int(&e->output, 1); 621 buffer_put_char(&e->output, 622 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 623 } 624 625 static void 626 no_identities(SocketEntry *e, u_int type) 627 { 628 Buffer msg; 629 630 buffer_init(&msg); 631 buffer_put_char(&msg, 632 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ? 633 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 634 buffer_put_int(&msg, 0); 635 buffer_put_int(&e->output, buffer_len(&msg)); 636 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 637 buffer_free(&msg); 638 } 639 640 #ifdef ENABLE_PKCS11 641 static void 642 process_add_smartcard_key(SocketEntry *e) 643 { 644 char *provider = NULL, *pin; 645 int i, type, version, count = 0, success = 0, death = 0, confirm = 0; 646 Key **keys = NULL, *k; 647 Identity *id; 648 Idtab *tab; 649 650 provider = buffer_get_string(&e->request, NULL); 651 pin = buffer_get_string(&e->request, NULL); 652 653 while (buffer_len(&e->request)) { 654 switch ((type = buffer_get_char(&e->request))) { 655 case SSH_AGENT_CONSTRAIN_LIFETIME: 656 death = time(NULL) + buffer_get_int(&e->request); 657 break; 658 case SSH_AGENT_CONSTRAIN_CONFIRM: 659 confirm = 1; 660 break; 661 default: 662 error("process_add_smartcard_key: " 663 "Unknown constraint type %d", type); 664 goto send; 665 } 666 } 667 if (lifetime && !death) 668 death = time(NULL) + lifetime; 669 670 count = pkcs11_add_provider(provider, pin, &keys); 671 for (i = 0; i < count; i++) { 672 k = keys[i]; 673 version = k->type == KEY_RSA1 ? 1 : 2; 674 tab = idtab_lookup(version); 675 if (lookup_identity(k, version) == NULL) { 676 id = xcalloc(1, sizeof(Identity)); 677 id->key = k; 678 id->provider = xstrdup(provider); 679 id->comment = xstrdup(provider); /* XXX */ 680 id->death = death; 681 id->confirm = confirm; 682 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 683 tab->nentries++; 684 success = 1; 685 } else { 686 key_free(k); 687 } 688 keys[i] = NULL; 689 } 690 send: 691 if (pin) 692 xfree(pin); 693 if (provider) 694 xfree(provider); 695 if (keys) 696 xfree(keys); 697 buffer_put_int(&e->output, 1); 698 buffer_put_char(&e->output, 699 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 700 } 701 702 static void 703 process_remove_smartcard_key(SocketEntry *e) 704 { 705 char *provider = NULL, *pin = NULL; 706 int version, success = 0; 707 Identity *id, *nxt; 708 Idtab *tab; 709 710 provider = buffer_get_string(&e->request, NULL); 711 pin = buffer_get_string(&e->request, NULL); 712 xfree(pin); 713 714 for (version = 1; version < 3; version++) { 715 tab = idtab_lookup(version); 716 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 717 nxt = TAILQ_NEXT(id, next); 718 if (!strcmp(provider, id->provider)) { 719 TAILQ_REMOVE(&tab->idlist, id, next); 720 free_identity(id); 721 tab->nentries--; 722 } 723 } 724 } 725 if (pkcs11_del_provider(provider) == 0) 726 success = 1; 727 else 728 error("process_remove_smartcard_key:" 729 " pkcs11_del_provider failed"); 730 xfree(provider); 731 buffer_put_int(&e->output, 1); 732 buffer_put_char(&e->output, 733 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 734 } 735 #endif /* ENABLE_PKCS11 */ 736 737 /* dispatch incoming messages */ 738 739 static void 740 process_message(SocketEntry *e) 741 { 742 u_int msg_len, type; 743 u_char *cp; 744 745 if (buffer_len(&e->input) < 5) 746 return; /* Incomplete message. */ 747 cp = buffer_ptr(&e->input); 748 msg_len = get_u32(cp); 749 if (msg_len > 256 * 1024) { 750 close_socket(e); 751 return; 752 } 753 if (buffer_len(&e->input) < msg_len + 4) 754 return; 755 756 /* move the current input to e->request */ 757 buffer_consume(&e->input, 4); 758 buffer_clear(&e->request); 759 buffer_append(&e->request, buffer_ptr(&e->input), msg_len); 760 buffer_consume(&e->input, msg_len); 761 type = buffer_get_char(&e->request); 762 763 /* check wheter agent is locked */ 764 if (locked && type != SSH_AGENTC_UNLOCK) { 765 buffer_clear(&e->request); 766 switch (type) { 767 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 768 case SSH2_AGENTC_REQUEST_IDENTITIES: 769 /* send empty lists */ 770 no_identities(e, type); 771 break; 772 default: 773 /* send a fail message for all other request types */ 774 buffer_put_int(&e->output, 1); 775 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 776 } 777 return; 778 } 779 780 debug("type %d", type); 781 switch (type) { 782 case SSH_AGENTC_LOCK: 783 case SSH_AGENTC_UNLOCK: 784 process_lock_agent(e, type == SSH_AGENTC_LOCK); 785 break; 786 /* ssh1 */ 787 case SSH_AGENTC_RSA_CHALLENGE: 788 process_authentication_challenge1(e); 789 break; 790 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 791 process_request_identities(e, 1); 792 break; 793 case SSH_AGENTC_ADD_RSA_IDENTITY: 794 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 795 process_add_identity(e, 1); 796 break; 797 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 798 process_remove_identity(e, 1); 799 break; 800 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 801 process_remove_all_identities(e, 1); 802 break; 803 /* ssh2 */ 804 case SSH2_AGENTC_SIGN_REQUEST: 805 process_sign_request2(e); 806 break; 807 case SSH2_AGENTC_REQUEST_IDENTITIES: 808 process_request_identities(e, 2); 809 break; 810 case SSH2_AGENTC_ADD_IDENTITY: 811 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 812 process_add_identity(e, 2); 813 break; 814 case SSH2_AGENTC_REMOVE_IDENTITY: 815 process_remove_identity(e, 2); 816 break; 817 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 818 process_remove_all_identities(e, 2); 819 break; 820 #ifdef ENABLE_PKCS11 821 case SSH_AGENTC_ADD_SMARTCARD_KEY: 822 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 823 process_add_smartcard_key(e); 824 break; 825 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 826 process_remove_smartcard_key(e); 827 break; 828 #endif /* ENABLE_PKCS11 */ 829 default: 830 /* Unknown message. Respond with failure. */ 831 error("Unknown message %d", type); 832 buffer_clear(&e->request); 833 buffer_put_int(&e->output, 1); 834 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 835 break; 836 } 837 } 838 839 static void 840 new_socket(sock_type type, int fd) 841 { 842 u_int i, old_alloc, new_alloc; 843 844 set_nonblock(fd); 845 846 if (fd > max_fd) 847 max_fd = fd; 848 849 for (i = 0; i < sockets_alloc; i++) 850 if (sockets[i].type == AUTH_UNUSED) { 851 sockets[i].fd = fd; 852 buffer_init(&sockets[i].input); 853 buffer_init(&sockets[i].output); 854 buffer_init(&sockets[i].request); 855 sockets[i].type = type; 856 return; 857 } 858 old_alloc = sockets_alloc; 859 new_alloc = sockets_alloc + 10; 860 sockets = xrealloc(sockets, new_alloc, sizeof(sockets[0])); 861 for (i = old_alloc; i < new_alloc; i++) 862 sockets[i].type = AUTH_UNUSED; 863 sockets_alloc = new_alloc; 864 sockets[old_alloc].fd = fd; 865 buffer_init(&sockets[old_alloc].input); 866 buffer_init(&sockets[old_alloc].output); 867 buffer_init(&sockets[old_alloc].request); 868 sockets[old_alloc].type = type; 869 } 870 871 static int 872 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp, 873 struct timeval **tvpp) 874 { 875 u_int i, sz, deadline; 876 int n = 0; 877 static struct timeval tv; 878 879 for (i = 0; i < sockets_alloc; i++) { 880 switch (sockets[i].type) { 881 case AUTH_SOCKET: 882 case AUTH_CONNECTION: 883 n = MAX(n, sockets[i].fd); 884 break; 885 case AUTH_UNUSED: 886 break; 887 default: 888 fatal("Unknown socket type %d", sockets[i].type); 889 break; 890 } 891 } 892 893 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 894 if (*fdrp == NULL || sz > *nallocp) { 895 if (*fdrp) 896 xfree(*fdrp); 897 if (*fdwp) 898 xfree(*fdwp); 899 *fdrp = xmalloc(sz); 900 *fdwp = xmalloc(sz); 901 *nallocp = sz; 902 } 903 if (n < *fdl) 904 debug("XXX shrink: %d < %d", n, *fdl); 905 *fdl = n; 906 memset(*fdrp, 0, sz); 907 memset(*fdwp, 0, sz); 908 909 for (i = 0; i < sockets_alloc; i++) { 910 switch (sockets[i].type) { 911 case AUTH_SOCKET: 912 case AUTH_CONNECTION: 913 FD_SET(sockets[i].fd, *fdrp); 914 if (buffer_len(&sockets[i].output) > 0) 915 FD_SET(sockets[i].fd, *fdwp); 916 break; 917 default: 918 break; 919 } 920 } 921 deadline = reaper(); 922 if (parent_alive_interval != 0) 923 deadline = (deadline == 0) ? parent_alive_interval : 924 MIN(deadline, parent_alive_interval); 925 if (deadline == 0) { 926 *tvpp = NULL; 927 } else { 928 tv.tv_sec = deadline; 929 tv.tv_usec = 0; 930 *tvpp = &tv; 931 } 932 return (1); 933 } 934 935 static void 936 after_select(fd_set *readset, fd_set *writeset) 937 { 938 struct sockaddr_un sunaddr; 939 socklen_t slen; 940 char buf[1024]; 941 int len, sock; 942 u_int i, orig_alloc; 943 uid_t euid; 944 gid_t egid; 945 946 for (i = 0, orig_alloc = sockets_alloc; i < orig_alloc; i++) 947 switch (sockets[i].type) { 948 case AUTH_UNUSED: 949 break; 950 case AUTH_SOCKET: 951 if (FD_ISSET(sockets[i].fd, readset)) { 952 slen = sizeof(sunaddr); 953 sock = accept(sockets[i].fd, 954 (struct sockaddr *)&sunaddr, &slen); 955 if (sock < 0) { 956 error("accept from AUTH_SOCKET: %s", 957 strerror(errno)); 958 break; 959 } 960 if (getpeereid(sock, &euid, &egid) < 0) { 961 error("getpeereid %d failed: %s", 962 sock, strerror(errno)); 963 close(sock); 964 break; 965 } 966 if ((euid != 0) && (getuid() != euid)) { 967 error("uid mismatch: " 968 "peer euid %u != uid %u", 969 (u_int) euid, (u_int) getuid()); 970 close(sock); 971 break; 972 } 973 new_socket(AUTH_CONNECTION, sock); 974 } 975 break; 976 case AUTH_CONNECTION: 977 if (buffer_len(&sockets[i].output) > 0 && 978 FD_ISSET(sockets[i].fd, writeset)) { 979 len = write(sockets[i].fd, 980 buffer_ptr(&sockets[i].output), 981 buffer_len(&sockets[i].output)); 982 if (len == -1 && (errno == EAGAIN || 983 errno == EWOULDBLOCK || 984 errno == EINTR)) 985 continue; 986 if (len <= 0) { 987 close_socket(&sockets[i]); 988 break; 989 } 990 buffer_consume(&sockets[i].output, len); 991 } 992 if (FD_ISSET(sockets[i].fd, readset)) { 993 len = read(sockets[i].fd, buf, sizeof(buf)); 994 if (len == -1 && (errno == EAGAIN || 995 errno == EWOULDBLOCK || 996 errno == EINTR)) 997 continue; 998 if (len <= 0) { 999 close_socket(&sockets[i]); 1000 break; 1001 } 1002 buffer_append(&sockets[i].input, buf, len); 1003 process_message(&sockets[i]); 1004 } 1005 break; 1006 default: 1007 fatal("Unknown type %d", sockets[i].type); 1008 } 1009 } 1010 1011 static void 1012 cleanup_socket(void) 1013 { 1014 if (socket_name[0]) 1015 unlink(socket_name); 1016 if (socket_dir[0]) 1017 rmdir(socket_dir); 1018 } 1019 1020 void 1021 cleanup_exit(int i) 1022 { 1023 cleanup_socket(); 1024 _exit(i); 1025 } 1026 1027 /*ARGSUSED*/ 1028 static void 1029 cleanup_handler(int sig) 1030 { 1031 cleanup_socket(); 1032 #ifdef ENABLE_PKCS11 1033 pkcs11_terminate(); 1034 #endif 1035 _exit(2); 1036 } 1037 1038 static void 1039 check_parent_exists(void) 1040 { 1041 if (parent_pid != -1 && kill(parent_pid, 0) < 0) { 1042 /* printf("Parent has died - Authentication agent exiting.\n"); */ 1043 cleanup_socket(); 1044 _exit(2); 1045 } 1046 } 1047 1048 static void 1049 usage(void) 1050 { 1051 fprintf(stderr, "usage: %s [options] [command [arg ...]]\n", 1052 __progname); 1053 fprintf(stderr, "Options:\n"); 1054 fprintf(stderr, " -c Generate C-shell commands on stdout.\n"); 1055 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n"); 1056 fprintf(stderr, " -k Kill the current agent.\n"); 1057 fprintf(stderr, " -d Debug mode.\n"); 1058 fprintf(stderr, " -a socket Bind agent socket to given name.\n"); 1059 fprintf(stderr, " -t life Default identity lifetime (seconds).\n"); 1060 exit(1); 1061 } 1062 1063 int 1064 main(int ac, char **av) 1065 { 1066 int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0; 1067 int sock, fd, ch, result, saved_errno; 1068 u_int nalloc; 1069 char *shell, *format, *pidstr, *agentsocket = NULL; 1070 fd_set *readsetp = NULL, *writesetp = NULL; 1071 struct sockaddr_un sunaddr; 1072 #ifdef HAVE_SETRLIMIT 1073 struct rlimit rlim; 1074 #endif 1075 int prev_mask; 1076 extern int optind; 1077 extern char *optarg; 1078 pid_t pid; 1079 char pidstrbuf[1 + 3 * sizeof pid]; 1080 struct timeval *tvp = NULL; 1081 size_t len; 1082 1083 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1084 sanitise_stdfd(); 1085 1086 /* drop */ 1087 setegid(getgid()); 1088 setgid(getgid()); 1089 setuid(geteuid()); 1090 1091 #if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE) 1092 /* Disable ptrace on Linux without sgid bit */ 1093 prctl(PR_SET_DUMPABLE, 0); 1094 #endif 1095 1096 SSLeay_add_all_algorithms(); 1097 1098 __progname = ssh_get_progname(av[0]); 1099 init_rng(); 1100 seed_rng(); 1101 1102 while ((ch = getopt(ac, av, "cdksa:t:")) != -1) { 1103 switch (ch) { 1104 case 'c': 1105 if (s_flag) 1106 usage(); 1107 c_flag++; 1108 break; 1109 case 'k': 1110 k_flag++; 1111 break; 1112 case 's': 1113 if (c_flag) 1114 usage(); 1115 s_flag++; 1116 break; 1117 case 'd': 1118 if (d_flag) 1119 usage(); 1120 d_flag++; 1121 break; 1122 case 'a': 1123 agentsocket = optarg; 1124 break; 1125 case 't': 1126 if ((lifetime = convtime(optarg)) == -1) { 1127 fprintf(stderr, "Invalid lifetime\n"); 1128 usage(); 1129 } 1130 break; 1131 default: 1132 usage(); 1133 } 1134 } 1135 ac -= optind; 1136 av += optind; 1137 1138 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag)) 1139 usage(); 1140 1141 if (ac == 0 && !c_flag && !s_flag) { 1142 shell = getenv("SHELL"); 1143 if (shell != NULL && (len = strlen(shell)) > 2 && 1144 strncmp(shell + len - 3, "csh", 3) == 0) 1145 c_flag = 1; 1146 } 1147 if (k_flag) { 1148 const char *errstr = NULL; 1149 1150 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1151 if (pidstr == NULL) { 1152 fprintf(stderr, "%s not set, cannot kill agent\n", 1153 SSH_AGENTPID_ENV_NAME); 1154 exit(1); 1155 } 1156 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr); 1157 if (errstr) { 1158 fprintf(stderr, 1159 "%s=\"%s\", which is not a good PID: %s\n", 1160 SSH_AGENTPID_ENV_NAME, pidstr, errstr); 1161 exit(1); 1162 } 1163 if (kill(pid, SIGTERM) == -1) { 1164 perror("kill"); 1165 exit(1); 1166 } 1167 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 1168 printf(format, SSH_AUTHSOCKET_ENV_NAME); 1169 printf(format, SSH_AGENTPID_ENV_NAME); 1170 printf("echo Agent pid %ld killed;\n", (long)pid); 1171 exit(0); 1172 } 1173 parent_pid = getpid(); 1174 1175 if (agentsocket == NULL) { 1176 /* Create private directory for agent socket */ 1177 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXXXX", sizeof socket_dir); 1178 if (mkdtemp(socket_dir) == NULL) { 1179 perror("mkdtemp: private socket dir"); 1180 exit(1); 1181 } 1182 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1183 (long)parent_pid); 1184 } else { 1185 /* Try to use specified agent socket */ 1186 socket_dir[0] = '\0'; 1187 strlcpy(socket_name, agentsocket, sizeof socket_name); 1188 } 1189 1190 /* 1191 * Create socket early so it will exist before command gets run from 1192 * the parent. 1193 */ 1194 sock = socket(AF_UNIX, SOCK_STREAM, 0); 1195 if (sock < 0) { 1196 perror("socket"); 1197 *socket_name = '\0'; /* Don't unlink any existing file */ 1198 cleanup_exit(1); 1199 } 1200 memset(&sunaddr, 0, sizeof(sunaddr)); 1201 sunaddr.sun_family = AF_UNIX; 1202 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); 1203 prev_mask = umask(0177); 1204 if (bind(sock, (struct sockaddr *) &sunaddr, sizeof(sunaddr)) < 0) { 1205 perror("bind"); 1206 *socket_name = '\0'; /* Don't unlink any existing file */ 1207 umask(prev_mask); 1208 cleanup_exit(1); 1209 } 1210 umask(prev_mask); 1211 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 1212 perror("listen"); 1213 cleanup_exit(1); 1214 } 1215 1216 /* 1217 * Fork, and have the parent execute the command, if any, or present 1218 * the socket data. The child continues as the authentication agent. 1219 */ 1220 if (d_flag) { 1221 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1); 1222 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1223 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1224 SSH_AUTHSOCKET_ENV_NAME); 1225 printf("echo Agent pid %ld;\n", (long)parent_pid); 1226 goto skip; 1227 } 1228 pid = fork(); 1229 if (pid == -1) { 1230 perror("fork"); 1231 cleanup_exit(1); 1232 } 1233 if (pid != 0) { /* Parent - execute the given command. */ 1234 close(sock); 1235 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1236 if (ac == 0) { 1237 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1238 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1239 SSH_AUTHSOCKET_ENV_NAME); 1240 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 1241 SSH_AGENTPID_ENV_NAME); 1242 printf("echo Agent pid %ld;\n", (long)pid); 1243 exit(0); 1244 } 1245 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1246 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1247 perror("setenv"); 1248 exit(1); 1249 } 1250 execvp(av[0], av); 1251 perror(av[0]); 1252 exit(1); 1253 } 1254 /* child */ 1255 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1256 1257 if (setsid() == -1) { 1258 error("setsid: %s", strerror(errno)); 1259 cleanup_exit(1); 1260 } 1261 1262 (void)chdir("/"); 1263 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1264 /* XXX might close listen socket */ 1265 (void)dup2(fd, STDIN_FILENO); 1266 (void)dup2(fd, STDOUT_FILENO); 1267 (void)dup2(fd, STDERR_FILENO); 1268 if (fd > 2) 1269 close(fd); 1270 } 1271 1272 #ifdef HAVE_SETRLIMIT 1273 /* deny core dumps, since memory contains unencrypted private keys */ 1274 rlim.rlim_cur = rlim.rlim_max = 0; 1275 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 1276 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1277 cleanup_exit(1); 1278 } 1279 #endif 1280 1281 skip: 1282 1283 #ifdef ENABLE_PKCS11 1284 pkcs11_init(0); 1285 #endif 1286 new_socket(AUTH_SOCKET, sock); 1287 if (ac > 0) 1288 parent_alive_interval = 10; 1289 idtab_init(); 1290 if (!d_flag) 1291 signal(SIGINT, SIG_IGN); 1292 signal(SIGPIPE, SIG_IGN); 1293 signal(SIGHUP, cleanup_handler); 1294 signal(SIGTERM, cleanup_handler); 1295 nalloc = 0; 1296 1297 while (1) { 1298 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp); 1299 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp); 1300 saved_errno = errno; 1301 if (parent_alive_interval != 0) 1302 check_parent_exists(); 1303 (void) reaper(); /* remove expired keys */ 1304 if (result < 0) { 1305 if (saved_errno == EINTR) 1306 continue; 1307 fatal("select: %s", strerror(saved_errno)); 1308 } else if (result > 0) 1309 after_select(readsetp, writesetp); 1310 } 1311 /* NOTREACHED */ 1312 } 1313