1 /* $NetBSD: ssh-agent.c,v 1.5 2010/11/21 18:29:49 adam Exp $ */ 2 /* $OpenBSD: ssh-agent.c,v 1.168 2010/08/16 04:06:06 djm Exp $ */ 3 /* 4 * Author: Tatu Ylonen <ylo@cs.hut.fi> 5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 6 * All rights reserved 7 * The authentication agent program. 8 * 9 * As far as I am concerned, the code I have written for this software 10 * can be used freely for any purpose. Any derived versions of this 11 * software must be clearly marked as such, and if the derived work is 12 * incompatible with the protocol description in the RFC file, it must be 13 * called by a name other than "ssh" or "Secure Shell". 14 * 15 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions 19 * are met: 20 * 1. Redistributions of source code must retain the above copyright 21 * notice, this list of conditions and the following disclaimer. 22 * 2. Redistributions in binary form must reproduce the above copyright 23 * notice, this list of conditions and the following disclaimer in the 24 * documentation and/or other materials provided with the distribution. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 29 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 30 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 31 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 35 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 36 */ 37 38 #include "includes.h" 39 __RCSID("$NetBSD: ssh-agent.c,v 1.5 2010/11/21 18:29:49 adam Exp $"); 40 #include <sys/types.h> 41 #include <sys/time.h> 42 #include <sys/queue.h> 43 #include <sys/resource.h> 44 #include <sys/types.h> 45 #include <sys/socket.h> 46 #include <sys/un.h> 47 #include <sys/param.h> 48 49 #include <openssl/evp.h> 50 #include <openssl/md5.h> 51 52 #include <errno.h> 53 #include <fcntl.h> 54 #include <paths.h> 55 #include <signal.h> 56 #include <stdlib.h> 57 #include <stdio.h> 58 #include <string.h> 59 #include <time.h> 60 #include <unistd.h> 61 62 #include "xmalloc.h" 63 #include "ssh.h" 64 #include "rsa.h" 65 #include "buffer.h" 66 #include "key.h" 67 #include "authfd.h" 68 #include "compat.h" 69 #include "log.h" 70 #include "misc.h" 71 #include "getpeereid.h" 72 73 #ifdef ENABLE_PKCS11 74 #include "ssh-pkcs11.h" 75 #endif 76 77 typedef enum { 78 AUTH_UNUSED, 79 AUTH_SOCKET, 80 AUTH_CONNECTION 81 } sock_type; 82 83 typedef struct { 84 int fd; 85 sock_type type; 86 Buffer input; 87 Buffer output; 88 Buffer request; 89 } SocketEntry; 90 91 u_int sockets_alloc = 0; 92 SocketEntry *sockets = NULL; 93 94 typedef struct identity { 95 TAILQ_ENTRY(identity) next; 96 Key *key; 97 char *comment; 98 char *provider; 99 u_int death; 100 u_int confirm; 101 } Identity; 102 103 typedef struct { 104 int nentries; 105 TAILQ_HEAD(idqueue, identity) idlist; 106 } Idtab; 107 108 /* private key table, one per protocol version */ 109 Idtab idtable[3]; 110 111 int max_fd = 0; 112 113 /* pid of shell == parent of agent */ 114 pid_t parent_pid = -1; 115 u_int parent_alive_interval = 0; 116 117 /* pathname and directory for AUTH_SOCKET */ 118 char socket_name[MAXPATHLEN]; 119 char socket_dir[MAXPATHLEN]; 120 121 /* locking */ 122 int locked = 0; 123 char *lock_passwd = NULL; 124 125 extern char *__progname; 126 127 /* Default lifetime (0 == forever) */ 128 static int lifetime = 0; 129 130 static void 131 close_socket(SocketEntry *e) 132 { 133 close(e->fd); 134 e->fd = -1; 135 e->type = AUTH_UNUSED; 136 buffer_free(&e->input); 137 buffer_free(&e->output); 138 buffer_free(&e->request); 139 } 140 141 static void 142 idtab_init(void) 143 { 144 int i; 145 146 for (i = 0; i <=2; i++) { 147 TAILQ_INIT(&idtable[i].idlist); 148 idtable[i].nentries = 0; 149 } 150 } 151 152 /* return private key table for requested protocol version */ 153 static Idtab * 154 idtab_lookup(int version) 155 { 156 if (version < 1 || version > 2) 157 fatal("internal error, bad protocol version %d", version); 158 return &idtable[version]; 159 } 160 161 static void 162 free_identity(Identity *id) 163 { 164 key_free(id->key); 165 if (id->provider != NULL) 166 xfree(id->provider); 167 xfree(id->comment); 168 xfree(id); 169 } 170 171 /* return matching private key for given public key */ 172 static Identity * 173 lookup_identity(Key *key, int version) 174 { 175 Identity *id; 176 177 Idtab *tab = idtab_lookup(version); 178 TAILQ_FOREACH(id, &tab->idlist, next) { 179 if (key_equal(key, id->key)) 180 return (id); 181 } 182 return (NULL); 183 } 184 185 /* Check confirmation of keysign request */ 186 static int 187 confirm_key(Identity *id) 188 { 189 char *p; 190 int ret = -1; 191 192 p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX); 193 if (ask_permission("Allow use of key %s?\nKey fingerprint %s.", 194 id->comment, p)) 195 ret = 0; 196 xfree(p); 197 198 return (ret); 199 } 200 201 /* send list of supported public keys to 'client' */ 202 static void 203 process_request_identities(SocketEntry *e, int version) 204 { 205 Idtab *tab = idtab_lookup(version); 206 Identity *id; 207 Buffer msg; 208 209 buffer_init(&msg); 210 buffer_put_char(&msg, (version == 1) ? 211 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 212 buffer_put_int(&msg, tab->nentries); 213 TAILQ_FOREACH(id, &tab->idlist, next) { 214 if (id->key->type == KEY_RSA1) { 215 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n)); 216 buffer_put_bignum(&msg, id->key->rsa->e); 217 buffer_put_bignum(&msg, id->key->rsa->n); 218 } else { 219 u_char *blob; 220 u_int blen; 221 key_to_blob(id->key, &blob, &blen); 222 buffer_put_string(&msg, blob, blen); 223 xfree(blob); 224 } 225 buffer_put_cstring(&msg, id->comment); 226 } 227 buffer_put_int(&e->output, buffer_len(&msg)); 228 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 229 buffer_free(&msg); 230 } 231 232 /* ssh1 only */ 233 static void 234 process_authentication_challenge1(SocketEntry *e) 235 { 236 u_char buf[32], mdbuf[16], session_id[16]; 237 u_int response_type; 238 BIGNUM *challenge; 239 Identity *id; 240 int i, len; 241 Buffer msg; 242 MD5_CTX md; 243 Key *key; 244 245 buffer_init(&msg); 246 key = key_new(KEY_RSA1); 247 if ((challenge = BN_new()) == NULL) 248 fatal("process_authentication_challenge1: BN_new failed"); 249 250 (void) buffer_get_int(&e->request); /* ignored */ 251 buffer_get_bignum(&e->request, key->rsa->e); 252 buffer_get_bignum(&e->request, key->rsa->n); 253 buffer_get_bignum(&e->request, challenge); 254 255 /* Only protocol 1.1 is supported */ 256 if (buffer_len(&e->request) == 0) 257 goto failure; 258 buffer_get(&e->request, session_id, 16); 259 response_type = buffer_get_int(&e->request); 260 if (response_type != 1) 261 goto failure; 262 263 id = lookup_identity(key, 1); 264 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) { 265 Key *private = id->key; 266 /* Decrypt the challenge using the private key. */ 267 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0) 268 goto failure; 269 270 /* The response is MD5 of decrypted challenge plus session id. */ 271 len = BN_num_bytes(challenge); 272 if (len <= 0 || len > 32) { 273 logit("process_authentication_challenge: bad challenge length %d", len); 274 goto failure; 275 } 276 memset(buf, 0, 32); 277 BN_bn2bin(challenge, buf + 32 - len); 278 MD5_Init(&md); 279 MD5_Update(&md, buf, 32); 280 MD5_Update(&md, session_id, 16); 281 MD5_Final(mdbuf, &md); 282 283 /* Send the response. */ 284 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE); 285 for (i = 0; i < 16; i++) 286 buffer_put_char(&msg, mdbuf[i]); 287 goto send; 288 } 289 290 failure: 291 /* Unknown identity or protocol error. Send failure. */ 292 buffer_put_char(&msg, SSH_AGENT_FAILURE); 293 send: 294 buffer_put_int(&e->output, buffer_len(&msg)); 295 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 296 key_free(key); 297 BN_clear_free(challenge); 298 buffer_free(&msg); 299 } 300 301 /* ssh2 only */ 302 static void 303 process_sign_request2(SocketEntry *e) 304 { 305 u_char *blob, *data, *signature = NULL; 306 u_int blen, dlen, slen = 0; 307 extern int datafellows; 308 int odatafellows; 309 int ok = -1, flags; 310 Buffer msg; 311 Key *key; 312 313 odatafellows = datafellows; 314 datafellows = 0; 315 316 blob = buffer_get_string(&e->request, &blen); 317 data = buffer_get_string(&e->request, &dlen); 318 319 flags = buffer_get_int(&e->request); 320 if (flags & SSH_AGENT_OLD_SIGNATURE) 321 datafellows = SSH_BUG_SIGBLOB; 322 323 key = key_from_blob(blob, blen); 324 if (key != NULL) { 325 Identity *id = lookup_identity(key, 2); 326 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) 327 ok = key_sign(id->key, &signature, &slen, data, dlen); 328 key_free(key); 329 } 330 buffer_init(&msg); 331 if (ok == 0) { 332 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); 333 buffer_put_string(&msg, signature, slen); 334 } else { 335 buffer_put_char(&msg, SSH_AGENT_FAILURE); 336 } 337 buffer_put_int(&e->output, buffer_len(&msg)); 338 buffer_append(&e->output, buffer_ptr(&msg), 339 buffer_len(&msg)); 340 buffer_free(&msg); 341 xfree(data); 342 xfree(blob); 343 if (signature != NULL) 344 xfree(signature); 345 datafellows = odatafellows; 346 } 347 348 /* shared */ 349 static void 350 process_remove_identity(SocketEntry *e, int version) 351 { 352 u_int blen, bits; 353 int success = 0; 354 Key *key = NULL; 355 u_char *blob; 356 357 switch (version) { 358 case 1: 359 key = key_new(KEY_RSA1); 360 bits = buffer_get_int(&e->request); 361 buffer_get_bignum(&e->request, key->rsa->e); 362 buffer_get_bignum(&e->request, key->rsa->n); 363 364 if (bits != key_size(key)) 365 logit("Warning: identity keysize mismatch: actual %u, announced %u", 366 key_size(key), bits); 367 break; 368 case 2: 369 blob = buffer_get_string(&e->request, &blen); 370 key = key_from_blob(blob, blen); 371 xfree(blob); 372 break; 373 } 374 if (key != NULL) { 375 Identity *id = lookup_identity(key, version); 376 if (id != NULL) { 377 /* 378 * We have this key. Free the old key. Since we 379 * don't want to leave empty slots in the middle of 380 * the array, we actually free the key there and move 381 * all the entries between the empty slot and the end 382 * of the array. 383 */ 384 Idtab *tab = idtab_lookup(version); 385 if (tab->nentries < 1) 386 fatal("process_remove_identity: " 387 "internal error: tab->nentries %d", 388 tab->nentries); 389 TAILQ_REMOVE(&tab->idlist, id, next); 390 free_identity(id); 391 tab->nentries--; 392 success = 1; 393 } 394 key_free(key); 395 } 396 buffer_put_int(&e->output, 1); 397 buffer_put_char(&e->output, 398 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 399 } 400 401 static void 402 process_remove_all_identities(SocketEntry *e, int version) 403 { 404 Idtab *tab = idtab_lookup(version); 405 Identity *id; 406 407 /* Loop over all identities and clear the keys. */ 408 while ((id = TAILQ_FIRST(&tab->idlist)) != NULL) { 409 TAILQ_REMOVE(&tab->idlist, id, next); 410 free_identity(id); 411 } 412 413 /* Mark that there are no identities. */ 414 tab->nentries = 0; 415 416 /* Send success. */ 417 buffer_put_int(&e->output, 1); 418 buffer_put_char(&e->output, SSH_AGENT_SUCCESS); 419 } 420 421 /* removes expired keys and returns number of seconds until the next expiry */ 422 static u_int 423 reaper(void) 424 { 425 u_int deadline = 0, now = time(NULL); 426 Identity *id, *nxt; 427 int version; 428 Idtab *tab; 429 430 for (version = 1; version < 3; version++) { 431 tab = idtab_lookup(version); 432 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 433 nxt = TAILQ_NEXT(id, next); 434 if (id->death == 0) 435 continue; 436 if (now >= id->death) { 437 debug("expiring key '%s'", id->comment); 438 TAILQ_REMOVE(&tab->idlist, id, next); 439 free_identity(id); 440 tab->nentries--; 441 } else 442 deadline = (deadline == 0) ? id->death : 443 MIN(deadline, id->death); 444 } 445 } 446 if (deadline == 0 || deadline <= now) 447 return 0; 448 else 449 return (deadline - now); 450 } 451 452 static void 453 process_add_identity(SocketEntry *e, int version) 454 { 455 Idtab *tab = idtab_lookup(version); 456 Identity *id; 457 int type, success = 0, death = 0, confirm = 0; 458 char *type_name, *comment; 459 Key *k = NULL; 460 u_char *cert; 461 u_int len; 462 463 switch (version) { 464 case 1: 465 k = key_new_private(KEY_RSA1); 466 (void) buffer_get_int(&e->request); /* ignored */ 467 buffer_get_bignum(&e->request, k->rsa->n); 468 buffer_get_bignum(&e->request, k->rsa->e); 469 buffer_get_bignum(&e->request, k->rsa->d); 470 buffer_get_bignum(&e->request, k->rsa->iqmp); 471 472 /* SSH and SSL have p and q swapped */ 473 buffer_get_bignum(&e->request, k->rsa->q); /* p */ 474 buffer_get_bignum(&e->request, k->rsa->p); /* q */ 475 476 /* Generate additional parameters */ 477 rsa_generate_additional_parameters(k->rsa); 478 break; 479 case 2: 480 type_name = buffer_get_string(&e->request, NULL); 481 type = key_type_from_name(type_name); 482 xfree(type_name); 483 switch (type) { 484 case KEY_DSA: 485 k = key_new_private(type); 486 buffer_get_bignum2(&e->request, k->dsa->p); 487 buffer_get_bignum2(&e->request, k->dsa->q); 488 buffer_get_bignum2(&e->request, k->dsa->g); 489 buffer_get_bignum2(&e->request, k->dsa->pub_key); 490 buffer_get_bignum2(&e->request, k->dsa->priv_key); 491 break; 492 case KEY_DSA_CERT_V00: 493 case KEY_DSA_CERT: 494 cert = buffer_get_string(&e->request, &len); 495 if ((k = key_from_blob(cert, len)) == NULL) 496 fatal("Certificate parse failed"); 497 xfree(cert); 498 key_add_private(k); 499 buffer_get_bignum2(&e->request, k->dsa->priv_key); 500 break; 501 case KEY_RSA: 502 k = key_new_private(type); 503 buffer_get_bignum2(&e->request, k->rsa->n); 504 buffer_get_bignum2(&e->request, k->rsa->e); 505 buffer_get_bignum2(&e->request, k->rsa->d); 506 buffer_get_bignum2(&e->request, k->rsa->iqmp); 507 buffer_get_bignum2(&e->request, k->rsa->p); 508 buffer_get_bignum2(&e->request, k->rsa->q); 509 510 /* Generate additional parameters */ 511 rsa_generate_additional_parameters(k->rsa); 512 break; 513 case KEY_RSA_CERT_V00: 514 case KEY_RSA_CERT: 515 cert = buffer_get_string(&e->request, &len); 516 if ((k = key_from_blob(cert, len)) == NULL) 517 fatal("Certificate parse failed"); 518 xfree(cert); 519 key_add_private(k); 520 buffer_get_bignum2(&e->request, k->rsa->d); 521 buffer_get_bignum2(&e->request, k->rsa->iqmp); 522 buffer_get_bignum2(&e->request, k->rsa->p); 523 buffer_get_bignum2(&e->request, k->rsa->q); 524 break; 525 default: 526 buffer_clear(&e->request); 527 goto send; 528 } 529 break; 530 } 531 /* enable blinding */ 532 switch (k->type) { 533 case KEY_RSA: 534 case KEY_RSA_CERT_V00: 535 case KEY_RSA_CERT: 536 case KEY_RSA1: 537 if (RSA_blinding_on(k->rsa, NULL) != 1) { 538 error("process_add_identity: RSA_blinding_on failed"); 539 key_free(k); 540 goto send; 541 } 542 break; 543 } 544 comment = buffer_get_string(&e->request, NULL); 545 if (k == NULL) { 546 xfree(comment); 547 goto send; 548 } 549 while (buffer_len(&e->request)) { 550 switch ((type = buffer_get_char(&e->request))) { 551 case SSH_AGENT_CONSTRAIN_LIFETIME: 552 death = time(NULL) + buffer_get_int(&e->request); 553 break; 554 case SSH_AGENT_CONSTRAIN_CONFIRM: 555 confirm = 1; 556 break; 557 default: 558 error("process_add_identity: " 559 "Unknown constraint type %d", type); 560 xfree(comment); 561 key_free(k); 562 goto send; 563 } 564 } 565 success = 1; 566 if (lifetime && !death) 567 death = time(NULL) + lifetime; 568 if ((id = lookup_identity(k, version)) == NULL) { 569 id = xcalloc(1, sizeof(Identity)); 570 id->key = k; 571 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 572 /* Increment the number of identities. */ 573 tab->nentries++; 574 } else { 575 key_free(k); 576 xfree(id->comment); 577 } 578 id->comment = comment; 579 id->death = death; 580 id->confirm = confirm; 581 send: 582 buffer_put_int(&e->output, 1); 583 buffer_put_char(&e->output, 584 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 585 } 586 587 /* XXX todo: encrypt sensitive data with passphrase */ 588 static void 589 process_lock_agent(SocketEntry *e, int lock) 590 { 591 int success = 0; 592 char *passwd; 593 594 passwd = buffer_get_string(&e->request, NULL); 595 if (locked && !lock && strcmp(passwd, lock_passwd) == 0) { 596 locked = 0; 597 memset(lock_passwd, 0, strlen(lock_passwd)); 598 xfree(lock_passwd); 599 lock_passwd = NULL; 600 success = 1; 601 } else if (!locked && lock) { 602 locked = 1; 603 lock_passwd = xstrdup(passwd); 604 success = 1; 605 } 606 memset(passwd, 0, strlen(passwd)); 607 xfree(passwd); 608 609 buffer_put_int(&e->output, 1); 610 buffer_put_char(&e->output, 611 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 612 } 613 614 static void 615 no_identities(SocketEntry *e, u_int type) 616 { 617 Buffer msg; 618 619 buffer_init(&msg); 620 buffer_put_char(&msg, 621 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ? 622 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 623 buffer_put_int(&msg, 0); 624 buffer_put_int(&e->output, buffer_len(&msg)); 625 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 626 buffer_free(&msg); 627 } 628 629 #ifdef ENABLE_PKCS11 630 static void 631 process_add_smartcard_key(SocketEntry *e) 632 { 633 char *provider = NULL, *pin; 634 int i, type, version, count = 0, success = 0, death = 0, confirm = 0; 635 Key **keys = NULL, *k; 636 Identity *id; 637 Idtab *tab; 638 639 provider = buffer_get_string(&e->request, NULL); 640 pin = buffer_get_string(&e->request, NULL); 641 642 while (buffer_len(&e->request)) { 643 switch ((type = buffer_get_char(&e->request))) { 644 case SSH_AGENT_CONSTRAIN_LIFETIME: 645 death = time(NULL) + buffer_get_int(&e->request); 646 break; 647 case SSH_AGENT_CONSTRAIN_CONFIRM: 648 confirm = 1; 649 break; 650 default: 651 error("process_add_smartcard_key: " 652 "Unknown constraint type %d", type); 653 goto send; 654 } 655 } 656 if (lifetime && !death) 657 death = time(NULL) + lifetime; 658 659 count = pkcs11_add_provider(provider, pin, &keys); 660 for (i = 0; i < count; i++) { 661 k = keys[i]; 662 version = k->type == KEY_RSA1 ? 1 : 2; 663 tab = idtab_lookup(version); 664 if (lookup_identity(k, version) == NULL) { 665 id = xcalloc(1, sizeof(Identity)); 666 id->key = k; 667 id->provider = xstrdup(provider); 668 id->comment = xstrdup(provider); /* XXX */ 669 id->death = death; 670 id->confirm = confirm; 671 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 672 tab->nentries++; 673 success = 1; 674 } else { 675 key_free(k); 676 } 677 keys[i] = NULL; 678 } 679 send: 680 if (pin) 681 xfree(pin); 682 if (provider) 683 xfree(provider); 684 if (keys) 685 xfree(keys); 686 buffer_put_int(&e->output, 1); 687 buffer_put_char(&e->output, 688 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 689 } 690 691 static void 692 process_remove_smartcard_key(SocketEntry *e) 693 { 694 char *provider = NULL, *pin = NULL; 695 int version, success = 0; 696 Identity *id, *nxt; 697 Idtab *tab; 698 699 provider = buffer_get_string(&e->request, NULL); 700 pin = buffer_get_string(&e->request, NULL); 701 xfree(pin); 702 703 for (version = 1; version < 3; version++) { 704 tab = idtab_lookup(version); 705 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 706 nxt = TAILQ_NEXT(id, next); 707 if (!strcmp(provider, id->provider)) { 708 TAILQ_REMOVE(&tab->idlist, id, next); 709 free_identity(id); 710 tab->nentries--; 711 } 712 } 713 } 714 if (pkcs11_del_provider(provider) == 0) 715 success = 1; 716 else 717 error("process_remove_smartcard_key:" 718 " pkcs11_del_provider failed"); 719 xfree(provider); 720 buffer_put_int(&e->output, 1); 721 buffer_put_char(&e->output, 722 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 723 } 724 #endif /* ENABLE_PKCS11 */ 725 726 /* dispatch incoming messages */ 727 728 static void 729 process_message(SocketEntry *e) 730 { 731 u_int msg_len, type; 732 u_char *cp; 733 734 if (buffer_len(&e->input) < 5) 735 return; /* Incomplete message. */ 736 cp = buffer_ptr(&e->input); 737 msg_len = get_u32(cp); 738 if (msg_len > 256 * 1024) { 739 close_socket(e); 740 return; 741 } 742 if (buffer_len(&e->input) < msg_len + 4) 743 return; 744 745 /* move the current input to e->request */ 746 buffer_consume(&e->input, 4); 747 buffer_clear(&e->request); 748 buffer_append(&e->request, buffer_ptr(&e->input), msg_len); 749 buffer_consume(&e->input, msg_len); 750 type = buffer_get_char(&e->request); 751 752 /* check wheter agent is locked */ 753 if (locked && type != SSH_AGENTC_UNLOCK) { 754 buffer_clear(&e->request); 755 switch (type) { 756 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 757 case SSH2_AGENTC_REQUEST_IDENTITIES: 758 /* send empty lists */ 759 no_identities(e, type); 760 break; 761 default: 762 /* send a fail message for all other request types */ 763 buffer_put_int(&e->output, 1); 764 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 765 } 766 return; 767 } 768 769 debug("type %d", type); 770 switch (type) { 771 case SSH_AGENTC_LOCK: 772 case SSH_AGENTC_UNLOCK: 773 process_lock_agent(e, type == SSH_AGENTC_LOCK); 774 break; 775 /* ssh1 */ 776 case SSH_AGENTC_RSA_CHALLENGE: 777 process_authentication_challenge1(e); 778 break; 779 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 780 process_request_identities(e, 1); 781 break; 782 case SSH_AGENTC_ADD_RSA_IDENTITY: 783 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 784 process_add_identity(e, 1); 785 break; 786 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 787 process_remove_identity(e, 1); 788 break; 789 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 790 process_remove_all_identities(e, 1); 791 break; 792 /* ssh2 */ 793 case SSH2_AGENTC_SIGN_REQUEST: 794 process_sign_request2(e); 795 break; 796 case SSH2_AGENTC_REQUEST_IDENTITIES: 797 process_request_identities(e, 2); 798 break; 799 case SSH2_AGENTC_ADD_IDENTITY: 800 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 801 process_add_identity(e, 2); 802 break; 803 case SSH2_AGENTC_REMOVE_IDENTITY: 804 process_remove_identity(e, 2); 805 break; 806 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 807 process_remove_all_identities(e, 2); 808 break; 809 #ifdef ENABLE_PKCS11 810 case SSH_AGENTC_ADD_SMARTCARD_KEY: 811 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 812 process_add_smartcard_key(e); 813 break; 814 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 815 process_remove_smartcard_key(e); 816 break; 817 #endif /* ENABLE_PKCS11 */ 818 default: 819 /* Unknown message. Respond with failure. */ 820 error("Unknown message %d", type); 821 buffer_clear(&e->request); 822 buffer_put_int(&e->output, 1); 823 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 824 break; 825 } 826 } 827 828 static void 829 new_socket(sock_type type, int fd) 830 { 831 u_int i, old_alloc, new_alloc; 832 833 set_nonblock(fd); 834 835 if (fd > max_fd) 836 max_fd = fd; 837 838 for (i = 0; i < sockets_alloc; i++) 839 if (sockets[i].type == AUTH_UNUSED) { 840 sockets[i].fd = fd; 841 buffer_init(&sockets[i].input); 842 buffer_init(&sockets[i].output); 843 buffer_init(&sockets[i].request); 844 sockets[i].type = type; 845 return; 846 } 847 old_alloc = sockets_alloc; 848 new_alloc = sockets_alloc + 10; 849 sockets = xrealloc(sockets, new_alloc, sizeof(sockets[0])); 850 for (i = old_alloc; i < new_alloc; i++) 851 sockets[i].type = AUTH_UNUSED; 852 sockets_alloc = new_alloc; 853 sockets[old_alloc].fd = fd; 854 buffer_init(&sockets[old_alloc].input); 855 buffer_init(&sockets[old_alloc].output); 856 buffer_init(&sockets[old_alloc].request); 857 sockets[old_alloc].type = type; 858 } 859 860 static int 861 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp, 862 struct timeval **tvpp) 863 { 864 u_int i, sz, deadline; 865 int n = 0; 866 static struct timeval tv; 867 868 for (i = 0; i < sockets_alloc; i++) { 869 switch (sockets[i].type) { 870 case AUTH_SOCKET: 871 case AUTH_CONNECTION: 872 n = MAX(n, sockets[i].fd); 873 break; 874 case AUTH_UNUSED: 875 break; 876 default: 877 fatal("Unknown socket type %d", sockets[i].type); 878 break; 879 } 880 } 881 882 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 883 if (*fdrp == NULL || sz > *nallocp) { 884 if (*fdrp) 885 xfree(*fdrp); 886 if (*fdwp) 887 xfree(*fdwp); 888 *fdrp = xmalloc(sz); 889 *fdwp = xmalloc(sz); 890 *nallocp = sz; 891 } 892 if (n < *fdl) 893 debug("XXX shrink: %d < %d", n, *fdl); 894 *fdl = n; 895 memset(*fdrp, 0, sz); 896 memset(*fdwp, 0, sz); 897 898 for (i = 0; i < sockets_alloc; i++) { 899 switch (sockets[i].type) { 900 case AUTH_SOCKET: 901 case AUTH_CONNECTION: 902 FD_SET(sockets[i].fd, *fdrp); 903 if (buffer_len(&sockets[i].output) > 0) 904 FD_SET(sockets[i].fd, *fdwp); 905 break; 906 default: 907 break; 908 } 909 } 910 deadline = reaper(); 911 if (parent_alive_interval != 0) 912 deadline = (deadline == 0) ? parent_alive_interval : 913 MIN(deadline, parent_alive_interval); 914 if (deadline == 0) { 915 *tvpp = NULL; 916 } else { 917 tv.tv_sec = deadline; 918 tv.tv_usec = 0; 919 *tvpp = &tv; 920 } 921 return (1); 922 } 923 924 static void 925 after_select(fd_set *readset, fd_set *writeset) 926 { 927 struct sockaddr_un sunaddr; 928 socklen_t slen; 929 char buf[1024]; 930 int len, sock; 931 u_int i, orig_alloc; 932 uid_t euid; 933 gid_t egid; 934 935 for (i = 0, orig_alloc = sockets_alloc; i < orig_alloc; i++) 936 switch (sockets[i].type) { 937 case AUTH_UNUSED: 938 break; 939 case AUTH_SOCKET: 940 if (FD_ISSET(sockets[i].fd, readset)) { 941 slen = sizeof(sunaddr); 942 sock = accept(sockets[i].fd, 943 (struct sockaddr *)&sunaddr, &slen); 944 if (sock < 0) { 945 error("accept from AUTH_SOCKET: %s", 946 strerror(errno)); 947 break; 948 } 949 if (getpeereid(sock, &euid, &egid) < 0) { 950 error("getpeereid %d failed: %s", 951 sock, strerror(errno)); 952 close(sock); 953 break; 954 } 955 if ((euid != 0) && (getuid() != euid)) { 956 error("uid mismatch: " 957 "peer euid %u != uid %u", 958 (u_int) euid, (u_int) getuid()); 959 close(sock); 960 break; 961 } 962 new_socket(AUTH_CONNECTION, sock); 963 } 964 break; 965 case AUTH_CONNECTION: 966 if (buffer_len(&sockets[i].output) > 0 && 967 FD_ISSET(sockets[i].fd, writeset)) { 968 len = write(sockets[i].fd, 969 buffer_ptr(&sockets[i].output), 970 buffer_len(&sockets[i].output)); 971 if (len == -1 && (errno == EAGAIN || 972 errno == EINTR)) 973 continue; 974 if (len <= 0) { 975 close_socket(&sockets[i]); 976 break; 977 } 978 buffer_consume(&sockets[i].output, len); 979 } 980 if (FD_ISSET(sockets[i].fd, readset)) { 981 len = read(sockets[i].fd, buf, sizeof(buf)); 982 if (len == -1 && (errno == EAGAIN || 983 errno == EINTR)) 984 continue; 985 if (len <= 0) { 986 close_socket(&sockets[i]); 987 break; 988 } 989 buffer_append(&sockets[i].input, buf, len); 990 process_message(&sockets[i]); 991 } 992 break; 993 default: 994 fatal("Unknown type %d", sockets[i].type); 995 } 996 } 997 998 static void 999 cleanup_socket(void) 1000 { 1001 if (socket_name[0]) 1002 unlink(socket_name); 1003 if (socket_dir[0]) 1004 rmdir(socket_dir); 1005 } 1006 1007 void 1008 cleanup_exit(int i) 1009 { 1010 cleanup_socket(); 1011 _exit(i); 1012 } 1013 1014 /*ARGSUSED*/ 1015 static void 1016 cleanup_handler(int sig) 1017 { 1018 cleanup_socket(); 1019 #ifdef ENABLE_PKCS11 1020 pkcs11_terminate(); 1021 #endif 1022 _exit(2); 1023 } 1024 1025 static void 1026 check_parent_exists(void) 1027 { 1028 if (parent_pid != -1 && kill(parent_pid, 0) < 0) { 1029 /* printf("Parent has died - Authentication agent exiting.\n"); */ 1030 cleanup_socket(); 1031 _exit(2); 1032 } 1033 } 1034 1035 static void 1036 usage(void) 1037 { 1038 fprintf(stderr, "usage: %s [options] [command [arg ...]]\n", 1039 __progname); 1040 fprintf(stderr, "Options:\n"); 1041 fprintf(stderr, " -c Generate C-shell commands on stdout.\n"); 1042 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n"); 1043 fprintf(stderr, " -k Kill the current agent.\n"); 1044 fprintf(stderr, " -d Debug mode.\n"); 1045 fprintf(stderr, " -a socket Bind agent socket to given name.\n"); 1046 fprintf(stderr, " -t life Default identity lifetime (seconds).\n"); 1047 exit(1); 1048 } 1049 1050 int 1051 main(int ac, char **av) 1052 { 1053 int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0; 1054 int sock, fd, ch, result, saved_errno; 1055 u_int nalloc; 1056 char *shell, *format, *pidstr, *agentsocket = NULL; 1057 fd_set *readsetp = NULL, *writesetp = NULL; 1058 struct sockaddr_un sunaddr; 1059 struct rlimit rlim; 1060 extern int optind; 1061 extern char *optarg; 1062 pid_t pid; 1063 char pidstrbuf[1 + 3 * sizeof pid]; 1064 struct timeval *tvp = NULL; 1065 size_t len; 1066 1067 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1068 sanitise_stdfd(); 1069 1070 /* drop */ 1071 setegid(getgid()); 1072 setgid(getgid()); 1073 1074 SSLeay_add_all_algorithms(); 1075 1076 while ((ch = getopt(ac, av, "cdksa:t:")) != -1) { 1077 switch (ch) { 1078 case 'c': 1079 if (s_flag) 1080 usage(); 1081 c_flag++; 1082 break; 1083 case 'k': 1084 k_flag++; 1085 break; 1086 case 's': 1087 if (c_flag) 1088 usage(); 1089 s_flag++; 1090 break; 1091 case 'd': 1092 if (d_flag) 1093 usage(); 1094 d_flag++; 1095 break; 1096 case 'a': 1097 agentsocket = optarg; 1098 break; 1099 case 't': 1100 if ((lifetime = convtime(optarg)) == -1) { 1101 fprintf(stderr, "Invalid lifetime\n"); 1102 usage(); 1103 } 1104 break; 1105 default: 1106 usage(); 1107 } 1108 } 1109 ac -= optind; 1110 av += optind; 1111 1112 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag)) 1113 usage(); 1114 1115 if (ac == 0 && !c_flag && !s_flag) { 1116 shell = getenv("SHELL"); 1117 if (shell != NULL && (len = strlen(shell)) > 2 && 1118 strncmp(shell + len - 3, "csh", 3) == 0) 1119 c_flag = 1; 1120 } 1121 if (k_flag) { 1122 const char *errstr = NULL; 1123 1124 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1125 if (pidstr == NULL) { 1126 fprintf(stderr, "%s not set, cannot kill agent\n", 1127 SSH_AGENTPID_ENV_NAME); 1128 exit(1); 1129 } 1130 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr); 1131 if (errstr) { 1132 fprintf(stderr, 1133 "%s=\"%s\", which is not a good PID: %s\n", 1134 SSH_AGENTPID_ENV_NAME, pidstr, errstr); 1135 exit(1); 1136 } 1137 if (kill(pid, SIGTERM) == -1) { 1138 perror("kill"); 1139 exit(1); 1140 } 1141 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 1142 printf(format, SSH_AUTHSOCKET_ENV_NAME); 1143 printf(format, SSH_AGENTPID_ENV_NAME); 1144 printf("echo Agent pid %ld killed;\n", (long)pid); 1145 exit(0); 1146 } 1147 parent_pid = getpid(); 1148 1149 if (agentsocket == NULL) { 1150 /* Create private directory for agent socket */ 1151 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXXXX", sizeof socket_dir); 1152 if (mkdtemp(socket_dir) == NULL) { 1153 perror("mkdtemp: private socket dir"); 1154 exit(1); 1155 } 1156 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1157 (long)parent_pid); 1158 } else { 1159 /* Try to use specified agent socket */ 1160 socket_dir[0] = '\0'; 1161 strlcpy(socket_name, agentsocket, sizeof socket_name); 1162 } 1163 1164 /* 1165 * Create socket early so it will exist before command gets run from 1166 * the parent. 1167 */ 1168 sock = socket(AF_UNIX, SOCK_STREAM, 0); 1169 if (sock < 0) { 1170 perror("socket"); 1171 *socket_name = '\0'; /* Don't unlink any existing file */ 1172 cleanup_exit(1); 1173 } 1174 memset(&sunaddr, 0, sizeof(sunaddr)); 1175 sunaddr.sun_family = AF_UNIX; 1176 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); 1177 if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) { 1178 perror("bind"); 1179 *socket_name = '\0'; /* Don't unlink any existing file */ 1180 cleanup_exit(1); 1181 } 1182 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 1183 perror("listen"); 1184 cleanup_exit(1); 1185 } 1186 1187 /* 1188 * Fork, and have the parent execute the command, if any, or present 1189 * the socket data. The child continues as the authentication agent. 1190 */ 1191 if (d_flag) { 1192 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1); 1193 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1194 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1195 SSH_AUTHSOCKET_ENV_NAME); 1196 printf("echo Agent pid %ld;\n", (long)parent_pid); 1197 goto skip; 1198 } 1199 pid = fork(); 1200 if (pid == -1) { 1201 perror("fork"); 1202 cleanup_exit(1); 1203 } 1204 if (pid != 0) { /* Parent - execute the given command. */ 1205 close(sock); 1206 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1207 if (ac == 0) { 1208 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1209 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1210 SSH_AUTHSOCKET_ENV_NAME); 1211 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 1212 SSH_AGENTPID_ENV_NAME); 1213 printf("echo Agent pid %ld;\n", (long)pid); 1214 exit(0); 1215 } 1216 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1217 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1218 perror("setenv"); 1219 exit(1); 1220 } 1221 execvp(av[0], av); 1222 perror(av[0]); 1223 exit(1); 1224 } 1225 /* child */ 1226 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1227 1228 if (setsid() == -1) { 1229 error("setsid: %s", strerror(errno)); 1230 cleanup_exit(1); 1231 } 1232 1233 (void)chdir("/"); 1234 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1235 /* XXX might close listen socket */ 1236 (void)dup2(fd, STDIN_FILENO); 1237 (void)dup2(fd, STDOUT_FILENO); 1238 (void)dup2(fd, STDERR_FILENO); 1239 if (fd > 2) 1240 close(fd); 1241 } 1242 1243 /* deny core dumps, since memory contains unencrypted private keys */ 1244 rlim.rlim_cur = rlim.rlim_max = 0; 1245 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 1246 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1247 cleanup_exit(1); 1248 } 1249 1250 skip: 1251 1252 #ifdef ENABLE_PKCS11 1253 pkcs11_init(0); 1254 #endif 1255 new_socket(AUTH_SOCKET, sock); 1256 if (ac > 0) 1257 parent_alive_interval = 10; 1258 idtab_init(); 1259 if (!d_flag) 1260 signal(SIGINT, SIG_IGN); 1261 signal(SIGPIPE, SIG_IGN); 1262 signal(SIGHUP, cleanup_handler); 1263 signal(SIGTERM, cleanup_handler); 1264 nalloc = 0; 1265 1266 while (1) { 1267 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp); 1268 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp); 1269 saved_errno = errno; 1270 if (parent_alive_interval != 0) 1271 check_parent_exists(); 1272 (void) reaper(); /* remove expired keys */ 1273 if (result < 0) { 1274 if (saved_errno == EINTR) 1275 continue; 1276 fatal("select: %s", strerror(saved_errno)); 1277 } else if (result > 0) 1278 after_select(readsetp, writesetp); 1279 } 1280 /* NOTREACHED */ 1281 } 1282