1 /* 2 * Author: Tatu Ylonen <ylo@cs.hut.fi> 3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 4 * All rights reserved 5 * The authentication agent program. 6 * 7 * As far as I am concerned, the code I have written for this software 8 * can be used freely for any purpose. Any derived versions of this 9 * software must be clearly marked as such, and if the derived work is 10 * incompatible with the protocol description in the RFC file, it must be 11 * called by a name other than "ssh" or "Secure Shell". 12 * 13 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 14 * 15 * Redistribution and use in source and binary forms, with or without 16 * modification, are permitted provided that the following conditions 17 * are met: 18 * 1. Redistributions of source code must retain the above copyright 19 * notice, this list of conditions and the following disclaimer. 20 * 2. Redistributions in binary form must reproduce the above copyright 21 * notice, this list of conditions and the following disclaimer in the 22 * documentation and/or other materials provided with the distribution. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 27 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 29 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34 */ 35 36 #include "includes.h" 37 #include "openbsd-compat/sys-queue.h" 38 RCSID("$OpenBSD: ssh-agent.c,v 1.105 2002/10/01 20:34:12 markus Exp $"); 39 RCSID("$FreeBSD: src/crypto/openssh/ssh-agent.c,v 1.2.2.10 2003/02/11 08:27:40 des Exp $"); 40 RCSID("$DragonFly: src/crypto/openssh/Attic/ssh-agent.c,v 1.2 2003/06/17 04:24:36 dillon Exp $"); 41 42 #include <openssl/evp.h> 43 #include <openssl/md5.h> 44 45 #include "ssh.h" 46 #include "rsa.h" 47 #include "buffer.h" 48 #include "bufaux.h" 49 #include "xmalloc.h" 50 #include "getput.h" 51 #include "key.h" 52 #include "authfd.h" 53 #include "compat.h" 54 #include "log.h" 55 56 #ifdef SMARTCARD 57 #include "scard.h" 58 #endif 59 60 typedef enum { 61 AUTH_UNUSED, 62 AUTH_SOCKET, 63 AUTH_CONNECTION 64 } sock_type; 65 66 typedef struct { 67 int fd; 68 sock_type type; 69 Buffer input; 70 Buffer output; 71 Buffer request; 72 } SocketEntry; 73 74 u_int sockets_alloc = 0; 75 SocketEntry *sockets = NULL; 76 77 typedef struct identity { 78 TAILQ_ENTRY(identity) next; 79 Key *key; 80 char *comment; 81 u_int death; 82 } Identity; 83 84 typedef struct { 85 int nentries; 86 TAILQ_HEAD(idqueue, identity) idlist; 87 } Idtab; 88 89 /* private key table, one per protocol version */ 90 Idtab idtable[3]; 91 92 int max_fd = 0; 93 94 /* pid of shell == parent of agent */ 95 pid_t parent_pid = -1; 96 97 /* pathname and directory for AUTH_SOCKET */ 98 char socket_name[1024]; 99 char socket_dir[1024]; 100 101 /* locking */ 102 int locked = 0; 103 char *lock_passwd = NULL; 104 105 #ifdef HAVE___PROGNAME 106 extern char *__progname; 107 #else 108 char *__progname; 109 #endif 110 111 static void 112 close_socket(SocketEntry *e) 113 { 114 close(e->fd); 115 e->fd = -1; 116 e->type = AUTH_UNUSED; 117 buffer_free(&e->input); 118 buffer_free(&e->output); 119 buffer_free(&e->request); 120 } 121 122 static void 123 idtab_init(void) 124 { 125 int i; 126 127 for (i = 0; i <=2; i++) { 128 TAILQ_INIT(&idtable[i].idlist); 129 idtable[i].nentries = 0; 130 } 131 } 132 133 /* return private key table for requested protocol version */ 134 static Idtab * 135 idtab_lookup(int version) 136 { 137 if (version < 1 || version > 2) 138 fatal("internal error, bad protocol version %d", version); 139 return &idtable[version]; 140 } 141 142 static void 143 free_identity(Identity *id) 144 { 145 key_free(id->key); 146 xfree(id->comment); 147 xfree(id); 148 } 149 150 /* return matching private key for given public key */ 151 static Identity * 152 lookup_identity(Key *key, int version) 153 { 154 Identity *id; 155 156 Idtab *tab = idtab_lookup(version); 157 TAILQ_FOREACH(id, &tab->idlist, next) { 158 if (key_equal(key, id->key)) 159 return (id); 160 } 161 return (NULL); 162 } 163 164 /* send list of supported public keys to 'client' */ 165 static void 166 process_request_identities(SocketEntry *e, int version) 167 { 168 Idtab *tab = idtab_lookup(version); 169 Identity *id; 170 Buffer msg; 171 172 buffer_init(&msg); 173 buffer_put_char(&msg, (version == 1) ? 174 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 175 buffer_put_int(&msg, tab->nentries); 176 TAILQ_FOREACH(id, &tab->idlist, next) { 177 if (id->key->type == KEY_RSA1) { 178 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n)); 179 buffer_put_bignum(&msg, id->key->rsa->e); 180 buffer_put_bignum(&msg, id->key->rsa->n); 181 } else { 182 u_char *blob; 183 u_int blen; 184 key_to_blob(id->key, &blob, &blen); 185 buffer_put_string(&msg, blob, blen); 186 xfree(blob); 187 } 188 buffer_put_cstring(&msg, id->comment); 189 } 190 buffer_put_int(&e->output, buffer_len(&msg)); 191 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 192 buffer_free(&msg); 193 } 194 195 /* ssh1 only */ 196 static void 197 process_authentication_challenge1(SocketEntry *e) 198 { 199 u_char buf[32], mdbuf[16], session_id[16]; 200 u_int response_type; 201 BIGNUM *challenge; 202 Identity *id; 203 int i, len; 204 Buffer msg; 205 MD5_CTX md; 206 Key *key; 207 208 buffer_init(&msg); 209 key = key_new(KEY_RSA1); 210 if ((challenge = BN_new()) == NULL) 211 fatal("process_authentication_challenge1: BN_new failed"); 212 213 (void) buffer_get_int(&e->request); /* ignored */ 214 buffer_get_bignum(&e->request, key->rsa->e); 215 buffer_get_bignum(&e->request, key->rsa->n); 216 buffer_get_bignum(&e->request, challenge); 217 218 /* Only protocol 1.1 is supported */ 219 if (buffer_len(&e->request) == 0) 220 goto failure; 221 buffer_get(&e->request, session_id, 16); 222 response_type = buffer_get_int(&e->request); 223 if (response_type != 1) 224 goto failure; 225 226 id = lookup_identity(key, 1); 227 if (id != NULL) { 228 Key *private = id->key; 229 /* Decrypt the challenge using the private key. */ 230 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0) 231 goto failure; 232 233 /* The response is MD5 of decrypted challenge plus session id. */ 234 len = BN_num_bytes(challenge); 235 if (len <= 0 || len > 32) { 236 log("process_authentication_challenge: bad challenge length %d", len); 237 goto failure; 238 } 239 memset(buf, 0, 32); 240 BN_bn2bin(challenge, buf + 32 - len); 241 MD5_Init(&md); 242 MD5_Update(&md, buf, 32); 243 MD5_Update(&md, session_id, 16); 244 MD5_Final(mdbuf, &md); 245 246 /* Send the response. */ 247 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE); 248 for (i = 0; i < 16; i++) 249 buffer_put_char(&msg, mdbuf[i]); 250 goto send; 251 } 252 253 failure: 254 /* Unknown identity or protocol error. Send failure. */ 255 buffer_put_char(&msg, SSH_AGENT_FAILURE); 256 send: 257 buffer_put_int(&e->output, buffer_len(&msg)); 258 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 259 key_free(key); 260 BN_clear_free(challenge); 261 buffer_free(&msg); 262 } 263 264 /* ssh2 only */ 265 static void 266 process_sign_request2(SocketEntry *e) 267 { 268 u_char *blob, *data, *signature = NULL; 269 u_int blen, dlen, slen = 0; 270 extern int datafellows; 271 int ok = -1, flags; 272 Buffer msg; 273 Key *key; 274 275 datafellows = 0; 276 277 blob = buffer_get_string(&e->request, &blen); 278 data = buffer_get_string(&e->request, &dlen); 279 280 flags = buffer_get_int(&e->request); 281 if (flags & SSH_AGENT_OLD_SIGNATURE) 282 datafellows = SSH_BUG_SIGBLOB; 283 284 key = key_from_blob(blob, blen); 285 if (key != NULL) { 286 Identity *id = lookup_identity(key, 2); 287 if (id != NULL) 288 ok = key_sign(id->key, &signature, &slen, data, dlen); 289 } 290 key_free(key); 291 buffer_init(&msg); 292 if (ok == 0) { 293 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); 294 buffer_put_string(&msg, signature, slen); 295 } else { 296 buffer_put_char(&msg, SSH_AGENT_FAILURE); 297 } 298 buffer_put_int(&e->output, buffer_len(&msg)); 299 buffer_append(&e->output, buffer_ptr(&msg), 300 buffer_len(&msg)); 301 buffer_free(&msg); 302 xfree(data); 303 xfree(blob); 304 if (signature != NULL) 305 xfree(signature); 306 } 307 308 /* shared */ 309 static void 310 process_remove_identity(SocketEntry *e, int version) 311 { 312 u_int blen, bits; 313 int success = 0; 314 Key *key = NULL; 315 u_char *blob; 316 317 switch (version) { 318 case 1: 319 key = key_new(KEY_RSA1); 320 bits = buffer_get_int(&e->request); 321 buffer_get_bignum(&e->request, key->rsa->e); 322 buffer_get_bignum(&e->request, key->rsa->n); 323 324 if (bits != key_size(key)) 325 log("Warning: identity keysize mismatch: actual %u, announced %u", 326 key_size(key), bits); 327 break; 328 case 2: 329 blob = buffer_get_string(&e->request, &blen); 330 key = key_from_blob(blob, blen); 331 xfree(blob); 332 break; 333 } 334 if (key != NULL) { 335 Identity *id = lookup_identity(key, version); 336 if (id != NULL) { 337 /* 338 * We have this key. Free the old key. Since we 339 * don\'t want to leave empty slots in the middle of 340 * the array, we actually free the key there and move 341 * all the entries between the empty slot and the end 342 * of the array. 343 */ 344 Idtab *tab = idtab_lookup(version); 345 if (tab->nentries < 1) 346 fatal("process_remove_identity: " 347 "internal error: tab->nentries %d", 348 tab->nentries); 349 TAILQ_REMOVE(&tab->idlist, id, next); 350 free_identity(id); 351 tab->nentries--; 352 success = 1; 353 } 354 key_free(key); 355 } 356 buffer_put_int(&e->output, 1); 357 buffer_put_char(&e->output, 358 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 359 } 360 361 static void 362 process_remove_all_identities(SocketEntry *e, int version) 363 { 364 Idtab *tab = idtab_lookup(version); 365 Identity *id; 366 367 /* Loop over all identities and clear the keys. */ 368 for (id = TAILQ_FIRST(&tab->idlist); id; 369 id = TAILQ_FIRST(&tab->idlist)) { 370 TAILQ_REMOVE(&tab->idlist, id, next); 371 free_identity(id); 372 } 373 374 /* Mark that there are no identities. */ 375 tab->nentries = 0; 376 377 /* Send success. */ 378 buffer_put_int(&e->output, 1); 379 buffer_put_char(&e->output, SSH_AGENT_SUCCESS); 380 } 381 382 static void 383 reaper(void) 384 { 385 u_int now = time(NULL); 386 Identity *id, *nxt; 387 int version; 388 Idtab *tab; 389 390 for (version = 1; version < 3; version++) { 391 tab = idtab_lookup(version); 392 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 393 nxt = TAILQ_NEXT(id, next); 394 if (id->death != 0 && now >= id->death) { 395 TAILQ_REMOVE(&tab->idlist, id, next); 396 free_identity(id); 397 tab->nentries--; 398 } 399 } 400 } 401 } 402 403 static void 404 process_add_identity(SocketEntry *e, int version) 405 { 406 Idtab *tab = idtab_lookup(version); 407 int type, success = 0, death = 0; 408 char *type_name, *comment; 409 Key *k = NULL; 410 411 switch (version) { 412 case 1: 413 k = key_new_private(KEY_RSA1); 414 (void) buffer_get_int(&e->request); /* ignored */ 415 buffer_get_bignum(&e->request, k->rsa->n); 416 buffer_get_bignum(&e->request, k->rsa->e); 417 buffer_get_bignum(&e->request, k->rsa->d); 418 buffer_get_bignum(&e->request, k->rsa->iqmp); 419 420 /* SSH and SSL have p and q swapped */ 421 buffer_get_bignum(&e->request, k->rsa->q); /* p */ 422 buffer_get_bignum(&e->request, k->rsa->p); /* q */ 423 424 /* Generate additional parameters */ 425 rsa_generate_additional_parameters(k->rsa); 426 break; 427 case 2: 428 type_name = buffer_get_string(&e->request, NULL); 429 type = key_type_from_name(type_name); 430 xfree(type_name); 431 switch (type) { 432 case KEY_DSA: 433 k = key_new_private(type); 434 buffer_get_bignum2(&e->request, k->dsa->p); 435 buffer_get_bignum2(&e->request, k->dsa->q); 436 buffer_get_bignum2(&e->request, k->dsa->g); 437 buffer_get_bignum2(&e->request, k->dsa->pub_key); 438 buffer_get_bignum2(&e->request, k->dsa->priv_key); 439 break; 440 case KEY_RSA: 441 k = key_new_private(type); 442 buffer_get_bignum2(&e->request, k->rsa->n); 443 buffer_get_bignum2(&e->request, k->rsa->e); 444 buffer_get_bignum2(&e->request, k->rsa->d); 445 buffer_get_bignum2(&e->request, k->rsa->iqmp); 446 buffer_get_bignum2(&e->request, k->rsa->p); 447 buffer_get_bignum2(&e->request, k->rsa->q); 448 449 /* Generate additional parameters */ 450 rsa_generate_additional_parameters(k->rsa); 451 break; 452 default: 453 buffer_clear(&e->request); 454 goto send; 455 } 456 break; 457 } 458 comment = buffer_get_string(&e->request, NULL); 459 if (k == NULL) { 460 xfree(comment); 461 goto send; 462 } 463 success = 1; 464 while (buffer_len(&e->request)) { 465 switch (buffer_get_char(&e->request)) { 466 case SSH_AGENT_CONSTRAIN_LIFETIME: 467 death = time(NULL) + buffer_get_int(&e->request); 468 break; 469 default: 470 break; 471 } 472 } 473 if (lookup_identity(k, version) == NULL) { 474 Identity *id = xmalloc(sizeof(Identity)); 475 id->key = k; 476 id->comment = comment; 477 id->death = death; 478 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 479 /* Increment the number of identities. */ 480 tab->nentries++; 481 } else { 482 key_free(k); 483 xfree(comment); 484 } 485 send: 486 buffer_put_int(&e->output, 1); 487 buffer_put_char(&e->output, 488 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 489 } 490 491 /* XXX todo: encrypt sensitive data with passphrase */ 492 static void 493 process_lock_agent(SocketEntry *e, int lock) 494 { 495 int success = 0; 496 char *passwd; 497 498 passwd = buffer_get_string(&e->request, NULL); 499 if (locked && !lock && strcmp(passwd, lock_passwd) == 0) { 500 locked = 0; 501 memset(lock_passwd, 0, strlen(lock_passwd)); 502 xfree(lock_passwd); 503 lock_passwd = NULL; 504 success = 1; 505 } else if (!locked && lock) { 506 locked = 1; 507 lock_passwd = xstrdup(passwd); 508 success = 1; 509 } 510 memset(passwd, 0, strlen(passwd)); 511 xfree(passwd); 512 513 buffer_put_int(&e->output, 1); 514 buffer_put_char(&e->output, 515 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 516 } 517 518 static void 519 no_identities(SocketEntry *e, u_int type) 520 { 521 Buffer msg; 522 523 buffer_init(&msg); 524 buffer_put_char(&msg, 525 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ? 526 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 527 buffer_put_int(&msg, 0); 528 buffer_put_int(&e->output, buffer_len(&msg)); 529 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 530 buffer_free(&msg); 531 } 532 533 #ifdef SMARTCARD 534 static void 535 process_add_smartcard_key (SocketEntry *e) 536 { 537 char *sc_reader_id = NULL, *pin; 538 int i, version, success = 0; 539 Key **keys, *k; 540 Identity *id; 541 Idtab *tab; 542 543 sc_reader_id = buffer_get_string(&e->request, NULL); 544 pin = buffer_get_string(&e->request, NULL); 545 keys = sc_get_keys(sc_reader_id, pin); 546 xfree(sc_reader_id); 547 xfree(pin); 548 549 if (keys == NULL || keys[0] == NULL) { 550 error("sc_get_keys failed"); 551 goto send; 552 } 553 for (i = 0; keys[i] != NULL; i++) { 554 k = keys[i]; 555 version = k->type == KEY_RSA1 ? 1 : 2; 556 tab = idtab_lookup(version); 557 if (lookup_identity(k, version) == NULL) { 558 id = xmalloc(sizeof(Identity)); 559 id->key = k; 560 id->comment = xstrdup("smartcard key"); 561 id->death = 0; 562 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 563 tab->nentries++; 564 success = 1; 565 } else { 566 key_free(k); 567 } 568 keys[i] = NULL; 569 } 570 xfree(keys); 571 send: 572 buffer_put_int(&e->output, 1); 573 buffer_put_char(&e->output, 574 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 575 } 576 577 static void 578 process_remove_smartcard_key(SocketEntry *e) 579 { 580 char *sc_reader_id = NULL, *pin; 581 int i, version, success = 0; 582 Key **keys, *k = NULL; 583 Identity *id; 584 Idtab *tab; 585 586 sc_reader_id = buffer_get_string(&e->request, NULL); 587 pin = buffer_get_string(&e->request, NULL); 588 keys = sc_get_keys(sc_reader_id, pin); 589 xfree(sc_reader_id); 590 xfree(pin); 591 592 if (keys == NULL || keys[0] == NULL) { 593 error("sc_get_keys failed"); 594 goto send; 595 } 596 for (i = 0; keys[i] != NULL; i++) { 597 k = keys[i]; 598 version = k->type == KEY_RSA1 ? 1 : 2; 599 if ((id = lookup_identity(k, version)) != NULL) { 600 tab = idtab_lookup(version); 601 TAILQ_REMOVE(&tab->idlist, id, next); 602 tab->nentries--; 603 free_identity(id); 604 success = 1; 605 } 606 key_free(k); 607 keys[i] = NULL; 608 } 609 xfree(keys); 610 send: 611 buffer_put_int(&e->output, 1); 612 buffer_put_char(&e->output, 613 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 614 } 615 #endif /* SMARTCARD */ 616 617 /* dispatch incoming messages */ 618 619 static void 620 process_message(SocketEntry *e) 621 { 622 u_int msg_len, type; 623 u_char *cp; 624 625 /* kill dead keys */ 626 reaper(); 627 628 if (buffer_len(&e->input) < 5) 629 return; /* Incomplete message. */ 630 cp = buffer_ptr(&e->input); 631 msg_len = GET_32BIT(cp); 632 if (msg_len > 256 * 1024) { 633 close_socket(e); 634 return; 635 } 636 if (buffer_len(&e->input) < msg_len + 4) 637 return; 638 639 /* move the current input to e->request */ 640 buffer_consume(&e->input, 4); 641 buffer_clear(&e->request); 642 buffer_append(&e->request, buffer_ptr(&e->input), msg_len); 643 buffer_consume(&e->input, msg_len); 644 type = buffer_get_char(&e->request); 645 646 /* check wheter agent is locked */ 647 if (locked && type != SSH_AGENTC_UNLOCK) { 648 buffer_clear(&e->request); 649 switch (type) { 650 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 651 case SSH2_AGENTC_REQUEST_IDENTITIES: 652 /* send empty lists */ 653 no_identities(e, type); 654 break; 655 default: 656 /* send a fail message for all other request types */ 657 buffer_put_int(&e->output, 1); 658 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 659 } 660 return; 661 } 662 663 debug("type %d", type); 664 switch (type) { 665 case SSH_AGENTC_LOCK: 666 case SSH_AGENTC_UNLOCK: 667 process_lock_agent(e, type == SSH_AGENTC_LOCK); 668 break; 669 /* ssh1 */ 670 case SSH_AGENTC_RSA_CHALLENGE: 671 process_authentication_challenge1(e); 672 break; 673 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 674 process_request_identities(e, 1); 675 break; 676 case SSH_AGENTC_ADD_RSA_IDENTITY: 677 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 678 process_add_identity(e, 1); 679 break; 680 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 681 process_remove_identity(e, 1); 682 break; 683 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 684 process_remove_all_identities(e, 1); 685 break; 686 /* ssh2 */ 687 case SSH2_AGENTC_SIGN_REQUEST: 688 process_sign_request2(e); 689 break; 690 case SSH2_AGENTC_REQUEST_IDENTITIES: 691 process_request_identities(e, 2); 692 break; 693 case SSH2_AGENTC_ADD_IDENTITY: 694 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 695 process_add_identity(e, 2); 696 break; 697 case SSH2_AGENTC_REMOVE_IDENTITY: 698 process_remove_identity(e, 2); 699 break; 700 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 701 process_remove_all_identities(e, 2); 702 break; 703 #ifdef SMARTCARD 704 case SSH_AGENTC_ADD_SMARTCARD_KEY: 705 process_add_smartcard_key(e); 706 break; 707 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 708 process_remove_smartcard_key(e); 709 break; 710 #endif /* SMARTCARD */ 711 default: 712 /* Unknown message. Respond with failure. */ 713 error("Unknown message %d", type); 714 buffer_clear(&e->request); 715 buffer_put_int(&e->output, 1); 716 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 717 break; 718 } 719 } 720 721 static void 722 new_socket(sock_type type, int fd) 723 { 724 u_int i, old_alloc; 725 726 if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) 727 error("fcntl O_NONBLOCK: %s", strerror(errno)); 728 729 if (fd > max_fd) 730 max_fd = fd; 731 732 for (i = 0; i < sockets_alloc; i++) 733 if (sockets[i].type == AUTH_UNUSED) { 734 sockets[i].fd = fd; 735 sockets[i].type = type; 736 buffer_init(&sockets[i].input); 737 buffer_init(&sockets[i].output); 738 buffer_init(&sockets[i].request); 739 return; 740 } 741 old_alloc = sockets_alloc; 742 sockets_alloc += 10; 743 if (sockets) 744 sockets = xrealloc(sockets, sockets_alloc * sizeof(sockets[0])); 745 else 746 sockets = xmalloc(sockets_alloc * sizeof(sockets[0])); 747 for (i = old_alloc; i < sockets_alloc; i++) 748 sockets[i].type = AUTH_UNUSED; 749 sockets[old_alloc].type = type; 750 sockets[old_alloc].fd = fd; 751 buffer_init(&sockets[old_alloc].input); 752 buffer_init(&sockets[old_alloc].output); 753 buffer_init(&sockets[old_alloc].request); 754 } 755 756 static int 757 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, int *nallocp) 758 { 759 u_int i, sz; 760 int n = 0; 761 762 for (i = 0; i < sockets_alloc; i++) { 763 switch (sockets[i].type) { 764 case AUTH_SOCKET: 765 case AUTH_CONNECTION: 766 n = MAX(n, sockets[i].fd); 767 break; 768 case AUTH_UNUSED: 769 break; 770 default: 771 fatal("Unknown socket type %d", sockets[i].type); 772 break; 773 } 774 } 775 776 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 777 if (*fdrp == NULL || sz > *nallocp) { 778 if (*fdrp) 779 xfree(*fdrp); 780 if (*fdwp) 781 xfree(*fdwp); 782 *fdrp = xmalloc(sz); 783 *fdwp = xmalloc(sz); 784 *nallocp = sz; 785 } 786 if (n < *fdl) 787 debug("XXX shrink: %d < %d", n, *fdl); 788 *fdl = n; 789 memset(*fdrp, 0, sz); 790 memset(*fdwp, 0, sz); 791 792 for (i = 0; i < sockets_alloc; i++) { 793 switch (sockets[i].type) { 794 case AUTH_SOCKET: 795 case AUTH_CONNECTION: 796 FD_SET(sockets[i].fd, *fdrp); 797 if (buffer_len(&sockets[i].output) > 0) 798 FD_SET(sockets[i].fd, *fdwp); 799 break; 800 default: 801 break; 802 } 803 } 804 return (1); 805 } 806 807 static void 808 after_select(fd_set *readset, fd_set *writeset) 809 { 810 struct sockaddr_un sunaddr; 811 socklen_t slen; 812 char buf[1024]; 813 int len, sock; 814 u_int i; 815 uid_t euid; 816 gid_t egid; 817 818 for (i = 0; i < sockets_alloc; i++) 819 switch (sockets[i].type) { 820 case AUTH_UNUSED: 821 break; 822 case AUTH_SOCKET: 823 if (FD_ISSET(sockets[i].fd, readset)) { 824 slen = sizeof(sunaddr); 825 sock = accept(sockets[i].fd, 826 (struct sockaddr *) &sunaddr, &slen); 827 if (sock < 0) { 828 error("accept from AUTH_SOCKET: %s", 829 strerror(errno)); 830 break; 831 } 832 if (getpeereid(sock, &euid, &egid) < 0) { 833 error("getpeereid %d failed: %s", 834 sock, strerror(errno)); 835 close(sock); 836 break; 837 } 838 if ((euid != 0) && (getuid() != euid)) { 839 error("uid mismatch: " 840 "peer euid %u != uid %u", 841 (u_int) euid, (u_int) getuid()); 842 close(sock); 843 break; 844 } 845 new_socket(AUTH_CONNECTION, sock); 846 } 847 break; 848 case AUTH_CONNECTION: 849 if (buffer_len(&sockets[i].output) > 0 && 850 FD_ISSET(sockets[i].fd, writeset)) { 851 do { 852 len = write(sockets[i].fd, 853 buffer_ptr(&sockets[i].output), 854 buffer_len(&sockets[i].output)); 855 if (len == -1 && (errno == EAGAIN || 856 errno == EINTR)) 857 continue; 858 break; 859 } while (1); 860 if (len <= 0) { 861 close_socket(&sockets[i]); 862 break; 863 } 864 buffer_consume(&sockets[i].output, len); 865 } 866 if (FD_ISSET(sockets[i].fd, readset)) { 867 do { 868 len = read(sockets[i].fd, buf, sizeof(buf)); 869 if (len == -1 && (errno == EAGAIN || 870 errno == EINTR)) 871 continue; 872 break; 873 } while (1); 874 if (len <= 0) { 875 close_socket(&sockets[i]); 876 break; 877 } 878 buffer_append(&sockets[i].input, buf, len); 879 process_message(&sockets[i]); 880 } 881 break; 882 default: 883 fatal("Unknown type %d", sockets[i].type); 884 } 885 } 886 887 static void 888 cleanup_socket(void *p) 889 { 890 if (socket_name[0]) 891 unlink(socket_name); 892 if (socket_dir[0]) 893 rmdir(socket_dir); 894 } 895 896 static void 897 cleanup_exit(int i) 898 { 899 cleanup_socket(NULL); 900 exit(i); 901 } 902 903 static void 904 cleanup_handler(int sig) 905 { 906 cleanup_socket(NULL); 907 _exit(2); 908 } 909 910 static void 911 check_parent_exists(int sig) 912 { 913 int save_errno = errno; 914 915 if (parent_pid != -1 && kill(parent_pid, 0) < 0) { 916 /* printf("Parent has died - Authentication agent exiting.\n"); */ 917 cleanup_handler(sig); /* safe */ 918 } 919 signal(SIGALRM, check_parent_exists); 920 alarm(10); 921 errno = save_errno; 922 } 923 924 static void 925 usage(void) 926 { 927 fprintf(stderr, "Usage: %s [options] [command [args ...]]\n", 928 __progname); 929 fprintf(stderr, "Options:\n"); 930 fprintf(stderr, " -c Generate C-shell commands on stdout.\n"); 931 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n"); 932 fprintf(stderr, " -k Kill the current agent.\n"); 933 fprintf(stderr, " -d Debug mode.\n"); 934 fprintf(stderr, " -a socket Bind agent socket to given name.\n"); 935 exit(1); 936 } 937 938 int 939 main(int ac, char **av) 940 { 941 int sock, c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0, ch, nalloc; 942 char *shell, *format, *pidstr, *agentsocket = NULL; 943 fd_set *readsetp = NULL, *writesetp = NULL; 944 struct sockaddr_un sunaddr; 945 #ifdef HAVE_SETRLIMIT 946 struct rlimit rlim; 947 #endif 948 #ifdef HAVE_CYGWIN 949 int prev_mask; 950 #endif 951 extern int optind; 952 extern char *optarg; 953 pid_t pid; 954 char pidstrbuf[1 + 3 * sizeof pid]; 955 956 /* drop */ 957 setegid(getgid()); 958 setgid(getgid()); 959 setuid(geteuid()); 960 961 SSLeay_add_all_algorithms(); 962 963 __progname = get_progname(av[0]); 964 init_rng(); 965 seed_rng(); 966 967 while ((ch = getopt(ac, av, "cdksa:")) != -1) { 968 switch (ch) { 969 case 'c': 970 if (s_flag) 971 usage(); 972 c_flag++; 973 break; 974 case 'k': 975 k_flag++; 976 break; 977 case 's': 978 if (c_flag) 979 usage(); 980 s_flag++; 981 break; 982 case 'd': 983 if (d_flag) 984 usage(); 985 d_flag++; 986 break; 987 case 'a': 988 agentsocket = optarg; 989 break; 990 default: 991 usage(); 992 } 993 } 994 ac -= optind; 995 av += optind; 996 997 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag)) 998 usage(); 999 1000 if (ac == 0 && !c_flag && !s_flag) { 1001 shell = getenv("SHELL"); 1002 if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0) 1003 c_flag = 1; 1004 } 1005 if (k_flag) { 1006 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1007 if (pidstr == NULL) { 1008 fprintf(stderr, "%s not set, cannot kill agent\n", 1009 SSH_AGENTPID_ENV_NAME); 1010 exit(1); 1011 } 1012 pid = atoi(pidstr); 1013 if (pid < 1) { 1014 fprintf(stderr, "%s=\"%s\", which is not a good PID\n", 1015 SSH_AGENTPID_ENV_NAME, pidstr); 1016 exit(1); 1017 } 1018 if (kill(pid, SIGTERM) == -1) { 1019 perror("kill"); 1020 exit(1); 1021 } 1022 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 1023 printf(format, SSH_AUTHSOCKET_ENV_NAME); 1024 printf(format, SSH_AGENTPID_ENV_NAME); 1025 printf("echo Agent pid %ld killed;\n", (long)pid); 1026 exit(0); 1027 } 1028 parent_pid = getpid(); 1029 1030 if (agentsocket == NULL) { 1031 /* Create private directory for agent socket */ 1032 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXX", sizeof socket_dir); 1033 if (mkdtemp(socket_dir) == NULL) { 1034 perror("mkdtemp: private socket dir"); 1035 exit(1); 1036 } 1037 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1038 (long)parent_pid); 1039 } else { 1040 /* Try to use specified agent socket */ 1041 socket_dir[0] = '\0'; 1042 strlcpy(socket_name, agentsocket, sizeof socket_name); 1043 } 1044 1045 /* 1046 * Create socket early so it will exist before command gets run from 1047 * the parent. 1048 */ 1049 sock = socket(AF_UNIX, SOCK_STREAM, 0); 1050 if (sock < 0) { 1051 perror("socket"); 1052 cleanup_exit(1); 1053 } 1054 memset(&sunaddr, 0, sizeof(sunaddr)); 1055 sunaddr.sun_family = AF_UNIX; 1056 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); 1057 #ifdef HAVE_CYGWIN 1058 prev_mask = umask(0177); 1059 #endif 1060 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) { 1061 perror("bind"); 1062 #ifdef HAVE_CYGWIN 1063 umask(prev_mask); 1064 #endif 1065 cleanup_exit(1); 1066 } 1067 #ifdef HAVE_CYGWIN 1068 umask(prev_mask); 1069 #endif 1070 if (listen(sock, 128) < 0) { 1071 perror("listen"); 1072 cleanup_exit(1); 1073 } 1074 1075 /* 1076 * Fork, and have the parent execute the command, if any, or present 1077 * the socket data. The child continues as the authentication agent. 1078 */ 1079 if (d_flag) { 1080 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1); 1081 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1082 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1083 SSH_AUTHSOCKET_ENV_NAME); 1084 printf("echo Agent pid %ld;\n", (long)parent_pid); 1085 goto skip; 1086 } 1087 pid = fork(); 1088 if (pid == -1) { 1089 perror("fork"); 1090 cleanup_exit(1); 1091 } 1092 if (pid != 0) { /* Parent - execute the given command. */ 1093 close(sock); 1094 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1095 if (ac == 0) { 1096 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1097 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1098 SSH_AUTHSOCKET_ENV_NAME); 1099 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 1100 SSH_AGENTPID_ENV_NAME); 1101 printf("echo Agent pid %ld;\n", (long)pid); 1102 exit(0); 1103 } 1104 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1105 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1106 perror("setenv"); 1107 exit(1); 1108 } 1109 execvp(av[0], av); 1110 perror(av[0]); 1111 exit(1); 1112 } 1113 /* child */ 1114 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1115 1116 if (setsid() == -1) { 1117 error("setsid: %s", strerror(errno)); 1118 cleanup_exit(1); 1119 } 1120 1121 (void)chdir("/"); 1122 close(0); 1123 close(1); 1124 close(2); 1125 1126 #ifdef HAVE_SETRLIMIT 1127 /* deny core dumps, since memory contains unencrypted private keys */ 1128 rlim.rlim_cur = rlim.rlim_max = 0; 1129 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 1130 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1131 cleanup_exit(1); 1132 } 1133 #endif 1134 1135 skip: 1136 fatal_add_cleanup(cleanup_socket, NULL); 1137 new_socket(AUTH_SOCKET, sock); 1138 if (ac > 0) { 1139 signal(SIGALRM, check_parent_exists); 1140 alarm(10); 1141 } 1142 idtab_init(); 1143 if (!d_flag) 1144 signal(SIGINT, SIG_IGN); 1145 signal(SIGPIPE, SIG_IGN); 1146 signal(SIGHUP, cleanup_handler); 1147 signal(SIGTERM, cleanup_handler); 1148 nalloc = 0; 1149 1150 while (1) { 1151 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc); 1152 if (select(max_fd + 1, readsetp, writesetp, NULL, NULL) < 0) { 1153 if (errno == EINTR) 1154 continue; 1155 fatal("select: %s", strerror(errno)); 1156 } 1157 after_select(readsetp, writesetp); 1158 } 1159 /* NOTREACHED */ 1160 } 1161