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 <sys/queue.h> 38 RCSID("$OpenBSD: ssh-agent.c,v 1.82 2002/03/04 17:27:39 stevesk Exp $"); 39 RCSID("$FreeBSD$"); 40 41 #include <openssl/evp.h> 42 #include <openssl/md5.h> 43 44 #include "ssh.h" 45 #include "rsa.h" 46 #include "buffer.h" 47 #include "bufaux.h" 48 #include "xmalloc.h" 49 #include "getput.h" 50 #include "key.h" 51 #include "authfd.h" 52 #include "compat.h" 53 #include "log.h" 54 55 #ifdef SMARTCARD 56 #include <openssl/engine.h> 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 } SocketEntry; 72 73 u_int sockets_alloc = 0; 74 SocketEntry *sockets = NULL; 75 76 typedef struct identity { 77 TAILQ_ENTRY(identity) next; 78 Key *key; 79 char *comment; 80 } Identity; 81 82 typedef struct { 83 int nentries; 84 TAILQ_HEAD(idqueue, identity) idlist; 85 } Idtab; 86 87 /* private key table, one per protocol version */ 88 Idtab idtable[3]; 89 90 int max_fd = 0; 91 92 /* pid of shell == parent of agent */ 93 pid_t parent_pid = -1; 94 95 /* pathname and directory for AUTH_SOCKET */ 96 char socket_name[1024]; 97 char socket_dir[1024]; 98 99 extern char *__progname; 100 101 static void 102 idtab_init(void) 103 { 104 int i; 105 for (i = 0; i <=2; i++) { 106 TAILQ_INIT(&idtable[i].idlist); 107 idtable[i].nentries = 0; 108 } 109 } 110 111 /* return private key table for requested protocol version */ 112 static Idtab * 113 idtab_lookup(int version) 114 { 115 if (version < 1 || version > 2) 116 fatal("internal error, bad protocol version %d", version); 117 return &idtable[version]; 118 } 119 120 /* return matching private key for given public key */ 121 static Identity * 122 lookup_identity(Key *key, int version) 123 { 124 Identity *id; 125 126 Idtab *tab = idtab_lookup(version); 127 TAILQ_FOREACH(id, &tab->idlist, next) { 128 if (key_equal(key, id->key)) 129 return (id); 130 } 131 return (NULL); 132 } 133 134 static void 135 free_identity(Identity *id) 136 { 137 key_free(id->key); 138 xfree(id->comment); 139 xfree(id); 140 } 141 142 /* send list of supported public keys to 'client' */ 143 static void 144 process_request_identities(SocketEntry *e, int version) 145 { 146 Idtab *tab = idtab_lookup(version); 147 Buffer msg; 148 Identity *id; 149 150 buffer_init(&msg); 151 buffer_put_char(&msg, (version == 1) ? 152 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 153 buffer_put_int(&msg, tab->nentries); 154 TAILQ_FOREACH(id, &tab->idlist, next) { 155 if (id->key->type == KEY_RSA1) { 156 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n)); 157 buffer_put_bignum(&msg, id->key->rsa->e); 158 buffer_put_bignum(&msg, id->key->rsa->n); 159 } else { 160 u_char *blob; 161 u_int blen; 162 key_to_blob(id->key, &blob, &blen); 163 buffer_put_string(&msg, blob, blen); 164 xfree(blob); 165 } 166 buffer_put_cstring(&msg, id->comment); 167 } 168 buffer_put_int(&e->output, buffer_len(&msg)); 169 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 170 buffer_free(&msg); 171 } 172 173 /* ssh1 only */ 174 static void 175 process_authentication_challenge1(SocketEntry *e) 176 { 177 Identity *id; 178 Key *key; 179 BIGNUM *challenge; 180 int i, len; 181 Buffer msg; 182 MD5_CTX md; 183 u_char buf[32], mdbuf[16], session_id[16]; 184 u_int response_type; 185 186 buffer_init(&msg); 187 key = key_new(KEY_RSA1); 188 if ((challenge = BN_new()) == NULL) 189 fatal("process_authentication_challenge1: BN_new failed"); 190 191 buffer_get_int(&e->input); /* ignored */ 192 buffer_get_bignum(&e->input, key->rsa->e); 193 buffer_get_bignum(&e->input, key->rsa->n); 194 buffer_get_bignum(&e->input, challenge); 195 196 /* Only protocol 1.1 is supported */ 197 if (buffer_len(&e->input) == 0) 198 goto failure; 199 buffer_get(&e->input, session_id, 16); 200 response_type = buffer_get_int(&e->input); 201 if (response_type != 1) 202 goto failure; 203 204 id = lookup_identity(key, 1); 205 if (id != NULL) { 206 Key *private = id->key; 207 /* Decrypt the challenge using the private key. */ 208 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0) 209 goto failure; 210 211 /* The response is MD5 of decrypted challenge plus session id. */ 212 len = BN_num_bytes(challenge); 213 if (len <= 0 || len > 32) { 214 log("process_authentication_challenge: bad challenge length %d", len); 215 goto failure; 216 } 217 memset(buf, 0, 32); 218 BN_bn2bin(challenge, buf + 32 - len); 219 MD5_Init(&md); 220 MD5_Update(&md, buf, 32); 221 MD5_Update(&md, session_id, 16); 222 MD5_Final(mdbuf, &md); 223 224 /* Send the response. */ 225 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE); 226 for (i = 0; i < 16; i++) 227 buffer_put_char(&msg, mdbuf[i]); 228 goto send; 229 } 230 231 failure: 232 /* Unknown identity or protocol error. Send failure. */ 233 buffer_put_char(&msg, SSH_AGENT_FAILURE); 234 send: 235 buffer_put_int(&e->output, buffer_len(&msg)); 236 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 237 key_free(key); 238 BN_clear_free(challenge); 239 buffer_free(&msg); 240 } 241 242 /* ssh2 only */ 243 static void 244 process_sign_request2(SocketEntry *e) 245 { 246 extern int datafellows; 247 Key *key; 248 u_char *blob, *data, *signature = NULL; 249 u_int blen, dlen, slen = 0; 250 int flags; 251 Buffer msg; 252 int ok = -1; 253 254 datafellows = 0; 255 256 blob = buffer_get_string(&e->input, &blen); 257 data = buffer_get_string(&e->input, &dlen); 258 259 flags = buffer_get_int(&e->input); 260 if (flags & SSH_AGENT_OLD_SIGNATURE) 261 datafellows = SSH_BUG_SIGBLOB; 262 263 key = key_from_blob(blob, blen); 264 if (key != NULL) { 265 Identity *id = lookup_identity(key, 2); 266 if (id != NULL) 267 ok = key_sign(id->key, &signature, &slen, data, dlen); 268 } 269 key_free(key); 270 buffer_init(&msg); 271 if (ok == 0) { 272 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); 273 buffer_put_string(&msg, signature, slen); 274 } else { 275 buffer_put_char(&msg, SSH_AGENT_FAILURE); 276 } 277 buffer_put_int(&e->output, buffer_len(&msg)); 278 buffer_append(&e->output, buffer_ptr(&msg), 279 buffer_len(&msg)); 280 buffer_free(&msg); 281 xfree(data); 282 xfree(blob); 283 if (signature != NULL) 284 xfree(signature); 285 } 286 287 /* shared */ 288 static void 289 process_remove_identity(SocketEntry *e, int version) 290 { 291 Key *key = NULL; 292 u_char *blob; 293 u_int blen; 294 u_int bits; 295 int success = 0; 296 297 switch (version) { 298 case 1: 299 key = key_new(KEY_RSA1); 300 bits = buffer_get_int(&e->input); 301 buffer_get_bignum(&e->input, key->rsa->e); 302 buffer_get_bignum(&e->input, key->rsa->n); 303 304 if (bits != key_size(key)) 305 log("Warning: identity keysize mismatch: actual %d, announced %d", 306 key_size(key), bits); 307 break; 308 case 2: 309 blob = buffer_get_string(&e->input, &blen); 310 key = key_from_blob(blob, blen); 311 xfree(blob); 312 break; 313 } 314 if (key != NULL) { 315 Identity *id = lookup_identity(key, version); 316 if (id != NULL) { 317 /* 318 * We have this key. Free the old key. Since we 319 * don\'t want to leave empty slots in the middle of 320 * the array, we actually free the key there and move 321 * all the entries between the empty slot and the end 322 * of the array. 323 */ 324 Idtab *tab = idtab_lookup(version); 325 if (tab->nentries < 1) 326 fatal("process_remove_identity: " 327 "internal error: tab->nentries %d", 328 tab->nentries); 329 TAILQ_REMOVE(&tab->idlist, id, next); 330 free_identity(id); 331 tab->nentries--; 332 success = 1; 333 } 334 key_free(key); 335 } 336 buffer_put_int(&e->output, 1); 337 buffer_put_char(&e->output, 338 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 339 } 340 341 static void 342 process_remove_all_identities(SocketEntry *e, int version) 343 { 344 Idtab *tab = idtab_lookup(version); 345 Identity *id; 346 347 /* Loop over all identities and clear the keys. */ 348 for (id = TAILQ_FIRST(&tab->idlist); id; 349 id = TAILQ_FIRST(&tab->idlist)) { 350 TAILQ_REMOVE(&tab->idlist, id, next); 351 free_identity(id); 352 } 353 354 /* Mark that there are no identities. */ 355 tab->nentries = 0; 356 357 /* Send success. */ 358 buffer_put_int(&e->output, 1); 359 buffer_put_char(&e->output, SSH_AGENT_SUCCESS); 360 return; 361 } 362 363 static void 364 process_add_identity(SocketEntry *e, int version) 365 { 366 Key *k = NULL; 367 char *type_name; 368 char *comment; 369 int type, success = 0; 370 Idtab *tab = idtab_lookup(version); 371 372 switch (version) { 373 case 1: 374 k = key_new_private(KEY_RSA1); 375 buffer_get_int(&e->input); /* ignored */ 376 buffer_get_bignum(&e->input, k->rsa->n); 377 buffer_get_bignum(&e->input, k->rsa->e); 378 buffer_get_bignum(&e->input, k->rsa->d); 379 buffer_get_bignum(&e->input, k->rsa->iqmp); 380 381 /* SSH and SSL have p and q swapped */ 382 buffer_get_bignum(&e->input, k->rsa->q); /* p */ 383 buffer_get_bignum(&e->input, k->rsa->p); /* q */ 384 385 /* Generate additional parameters */ 386 rsa_generate_additional_parameters(k->rsa); 387 break; 388 case 2: 389 type_name = buffer_get_string(&e->input, NULL); 390 type = key_type_from_name(type_name); 391 xfree(type_name); 392 switch (type) { 393 case KEY_DSA: 394 k = key_new_private(type); 395 buffer_get_bignum2(&e->input, k->dsa->p); 396 buffer_get_bignum2(&e->input, k->dsa->q); 397 buffer_get_bignum2(&e->input, k->dsa->g); 398 buffer_get_bignum2(&e->input, k->dsa->pub_key); 399 buffer_get_bignum2(&e->input, k->dsa->priv_key); 400 break; 401 case KEY_RSA: 402 k = key_new_private(type); 403 buffer_get_bignum2(&e->input, k->rsa->n); 404 buffer_get_bignum2(&e->input, k->rsa->e); 405 buffer_get_bignum2(&e->input, k->rsa->d); 406 buffer_get_bignum2(&e->input, k->rsa->iqmp); 407 buffer_get_bignum2(&e->input, k->rsa->p); 408 buffer_get_bignum2(&e->input, k->rsa->q); 409 410 /* Generate additional parameters */ 411 rsa_generate_additional_parameters(k->rsa); 412 break; 413 default: 414 buffer_clear(&e->input); 415 goto send; 416 } 417 break; 418 } 419 comment = buffer_get_string(&e->input, NULL); 420 if (k == NULL) { 421 xfree(comment); 422 goto send; 423 } 424 success = 1; 425 if (lookup_identity(k, version) == NULL) { 426 Identity *id = xmalloc(sizeof(Identity)); 427 id->key = k; 428 id->comment = comment; 429 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 430 /* Increment the number of identities. */ 431 tab->nentries++; 432 } else { 433 key_free(k); 434 xfree(comment); 435 } 436 send: 437 buffer_put_int(&e->output, 1); 438 buffer_put_char(&e->output, 439 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 440 } 441 442 443 #ifdef SMARTCARD 444 static void 445 process_add_smartcard_key (SocketEntry *e) 446 { 447 Idtab *tab; 448 Key *n = NULL, *k = NULL; 449 char *sc_reader_id = NULL; 450 int success = 0; 451 452 sc_reader_id = buffer_get_string(&e->input, NULL); 453 k = sc_get_key(sc_reader_id); 454 xfree(sc_reader_id); 455 456 if (k == NULL) { 457 error("sc_get_pubkey failed"); 458 goto send; 459 } 460 success = 1; 461 462 tab = idtab_lookup(1); 463 k->type = KEY_RSA1; 464 if (lookup_identity(k, 1) == NULL) { 465 Identity *id = xmalloc(sizeof(Identity)); 466 n = key_new(KEY_RSA1); 467 BN_copy(n->rsa->n, k->rsa->n); 468 BN_copy(n->rsa->e, k->rsa->e); 469 RSA_set_method(n->rsa, sc_get_engine()); 470 id->key = n; 471 id->comment = xstrdup("rsa1 smartcard"); 472 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 473 tab->nentries++; 474 } 475 k->type = KEY_RSA; 476 tab = idtab_lookup(2); 477 if (lookup_identity(k, 2) == NULL) { 478 Identity *id = xmalloc(sizeof(Identity)); 479 n = key_new(KEY_RSA); 480 BN_copy(n->rsa->n, k->rsa->n); 481 BN_copy(n->rsa->e, k->rsa->e); 482 RSA_set_method(n->rsa, sc_get_engine()); 483 id->key = n; 484 id->comment = xstrdup("rsa smartcard"); 485 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 486 tab->nentries++; 487 } 488 key_free(k); 489 send: 490 buffer_put_int(&e->output, 1); 491 buffer_put_char(&e->output, 492 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 493 } 494 495 static void 496 process_remove_smartcard_key(SocketEntry *e) 497 { 498 Key *k = NULL; 499 int success = 0; 500 char *sc_reader_id = NULL; 501 502 sc_reader_id = buffer_get_string(&e->input, NULL); 503 k = sc_get_key(sc_reader_id); 504 xfree(sc_reader_id); 505 506 if (k == NULL) { 507 error("sc_get_pubkey failed"); 508 } else { 509 Identity *id; 510 k->type = KEY_RSA1; 511 id = lookup_identity(k, 1); 512 if (id != NULL) { 513 Idtab *tab = idtab_lookup(1); 514 TAILQ_REMOVE(&tab->idlist, id, next); 515 free_identity(id); 516 tab->nentries--; 517 success = 1; 518 } 519 k->type = KEY_RSA; 520 id = lookup_identity(k, 2); 521 if (id != NULL) { 522 Idtab *tab = idtab_lookup(2); 523 TAILQ_REMOVE(&tab->idlist, id, next); 524 free_identity(id); 525 tab->nentries--; 526 success = 1; 527 } 528 key_free(k); 529 } 530 531 buffer_put_int(&e->output, 1); 532 buffer_put_char(&e->output, 533 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 534 } 535 #endif /* SMARTCARD */ 536 537 /* dispatch incoming messages */ 538 539 static void 540 process_message(SocketEntry *e) 541 { 542 u_int msg_len; 543 u_int type; 544 u_char *cp; 545 if (buffer_len(&e->input) < 5) 546 return; /* Incomplete message. */ 547 cp = buffer_ptr(&e->input); 548 msg_len = GET_32BIT(cp); 549 if (msg_len > 256 * 1024) { 550 shutdown(e->fd, SHUT_RDWR); 551 close(e->fd); 552 e->type = AUTH_UNUSED; 553 return; 554 } 555 if (buffer_len(&e->input) < msg_len + 4) 556 return; 557 buffer_consume(&e->input, 4); 558 type = buffer_get_char(&e->input); 559 560 debug("type %d", type); 561 switch (type) { 562 /* ssh1 */ 563 case SSH_AGENTC_RSA_CHALLENGE: 564 process_authentication_challenge1(e); 565 break; 566 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 567 process_request_identities(e, 1); 568 break; 569 case SSH_AGENTC_ADD_RSA_IDENTITY: 570 process_add_identity(e, 1); 571 break; 572 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 573 process_remove_identity(e, 1); 574 break; 575 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 576 process_remove_all_identities(e, 1); 577 break; 578 /* ssh2 */ 579 case SSH2_AGENTC_SIGN_REQUEST: 580 process_sign_request2(e); 581 break; 582 case SSH2_AGENTC_REQUEST_IDENTITIES: 583 process_request_identities(e, 2); 584 break; 585 case SSH2_AGENTC_ADD_IDENTITY: 586 process_add_identity(e, 2); 587 break; 588 case SSH2_AGENTC_REMOVE_IDENTITY: 589 process_remove_identity(e, 2); 590 break; 591 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 592 process_remove_all_identities(e, 2); 593 break; 594 #ifdef SMARTCARD 595 case SSH_AGENTC_ADD_SMARTCARD_KEY: 596 process_add_smartcard_key(e); 597 break; 598 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 599 process_remove_smartcard_key(e); 600 break; 601 #endif /* SMARTCARD */ 602 default: 603 /* Unknown message. Respond with failure. */ 604 error("Unknown message %d", type); 605 buffer_clear(&e->input); 606 buffer_put_int(&e->output, 1); 607 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 608 break; 609 } 610 } 611 612 static void 613 new_socket(sock_type type, int fd) 614 { 615 u_int i, old_alloc; 616 if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) 617 error("fcntl O_NONBLOCK: %s", strerror(errno)); 618 619 if (fd > max_fd) 620 max_fd = fd; 621 622 for (i = 0; i < sockets_alloc; i++) 623 if (sockets[i].type == AUTH_UNUSED) { 624 sockets[i].fd = fd; 625 sockets[i].type = type; 626 buffer_init(&sockets[i].input); 627 buffer_init(&sockets[i].output); 628 return; 629 } 630 old_alloc = sockets_alloc; 631 sockets_alloc += 10; 632 if (sockets) 633 sockets = xrealloc(sockets, sockets_alloc * sizeof(sockets[0])); 634 else 635 sockets = xmalloc(sockets_alloc * sizeof(sockets[0])); 636 for (i = old_alloc; i < sockets_alloc; i++) 637 sockets[i].type = AUTH_UNUSED; 638 sockets[old_alloc].type = type; 639 sockets[old_alloc].fd = fd; 640 buffer_init(&sockets[old_alloc].input); 641 buffer_init(&sockets[old_alloc].output); 642 } 643 644 static int 645 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, int *nallocp) 646 { 647 u_int i, sz; 648 int n = 0; 649 650 for (i = 0; i < sockets_alloc; i++) { 651 switch (sockets[i].type) { 652 case AUTH_SOCKET: 653 case AUTH_CONNECTION: 654 n = MAX(n, sockets[i].fd); 655 break; 656 case AUTH_UNUSED: 657 break; 658 default: 659 fatal("Unknown socket type %d", sockets[i].type); 660 break; 661 } 662 } 663 664 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 665 if (*fdrp == NULL || sz > *nallocp) { 666 if (*fdrp) 667 xfree(*fdrp); 668 if (*fdwp) 669 xfree(*fdwp); 670 *fdrp = xmalloc(sz); 671 *fdwp = xmalloc(sz); 672 *nallocp = sz; 673 } 674 if (n < *fdl) 675 debug("XXX shrink: %d < %d", n, *fdl); 676 *fdl = n; 677 memset(*fdrp, 0, sz); 678 memset(*fdwp, 0, sz); 679 680 for (i = 0; i < sockets_alloc; i++) { 681 switch (sockets[i].type) { 682 case AUTH_SOCKET: 683 case AUTH_CONNECTION: 684 FD_SET(sockets[i].fd, *fdrp); 685 if (buffer_len(&sockets[i].output) > 0) 686 FD_SET(sockets[i].fd, *fdwp); 687 break; 688 default: 689 break; 690 } 691 } 692 return (1); 693 } 694 695 static void 696 after_select(fd_set *readset, fd_set *writeset) 697 { 698 u_int i; 699 int len, sock; 700 socklen_t slen; 701 char buf[1024]; 702 struct sockaddr_un sunaddr; 703 704 for (i = 0; i < sockets_alloc; i++) 705 switch (sockets[i].type) { 706 case AUTH_UNUSED: 707 break; 708 case AUTH_SOCKET: 709 if (FD_ISSET(sockets[i].fd, readset)) { 710 slen = sizeof(sunaddr); 711 sock = accept(sockets[i].fd, 712 (struct sockaddr *) &sunaddr, &slen); 713 if (sock < 0) { 714 error("accept from AUTH_SOCKET: %s", 715 strerror(errno)); 716 break; 717 } 718 new_socket(AUTH_CONNECTION, sock); 719 } 720 break; 721 case AUTH_CONNECTION: 722 if (buffer_len(&sockets[i].output) > 0 && 723 FD_ISSET(sockets[i].fd, writeset)) { 724 do { 725 len = write(sockets[i].fd, 726 buffer_ptr(&sockets[i].output), 727 buffer_len(&sockets[i].output)); 728 if (len == -1 && (errno == EAGAIN || 729 errno == EINTR)) 730 continue; 731 break; 732 } while (1); 733 if (len <= 0) { 734 shutdown(sockets[i].fd, SHUT_RDWR); 735 close(sockets[i].fd); 736 sockets[i].type = AUTH_UNUSED; 737 buffer_free(&sockets[i].input); 738 buffer_free(&sockets[i].output); 739 break; 740 } 741 buffer_consume(&sockets[i].output, len); 742 } 743 if (FD_ISSET(sockets[i].fd, readset)) { 744 do { 745 len = read(sockets[i].fd, buf, sizeof(buf)); 746 if (len == -1 && (errno == EAGAIN || 747 errno == EINTR)) 748 continue; 749 break; 750 } while (1); 751 if (len <= 0) { 752 shutdown(sockets[i].fd, SHUT_RDWR); 753 close(sockets[i].fd); 754 sockets[i].type = AUTH_UNUSED; 755 buffer_free(&sockets[i].input); 756 buffer_free(&sockets[i].output); 757 break; 758 } 759 buffer_append(&sockets[i].input, buf, len); 760 process_message(&sockets[i]); 761 } 762 break; 763 default: 764 fatal("Unknown type %d", sockets[i].type); 765 } 766 } 767 768 static void 769 cleanup_socket(void *p) 770 { 771 if (socket_name[0]) 772 unlink(socket_name); 773 if (socket_dir[0]) 774 rmdir(socket_dir); 775 } 776 777 static void 778 cleanup_exit(int i) 779 { 780 cleanup_socket(NULL); 781 exit(i); 782 } 783 784 static void 785 cleanup_handler(int sig) 786 { 787 cleanup_socket(NULL); 788 _exit(2); 789 } 790 791 static void 792 check_parent_exists(int sig) 793 { 794 int save_errno = errno; 795 796 if (parent_pid != -1 && kill(parent_pid, 0) < 0) { 797 /* printf("Parent has died - Authentication agent exiting.\n"); */ 798 cleanup_handler(sig); /* safe */ 799 } 800 signal(SIGALRM, check_parent_exists); 801 alarm(10); 802 errno = save_errno; 803 } 804 805 static void 806 usage(void) 807 { 808 fprintf(stderr, "Usage: %s [options] [command [args ...]]\n", 809 __progname); 810 fprintf(stderr, "Options:\n"); 811 fprintf(stderr, " -c Generate C-shell commands on stdout.\n"); 812 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n"); 813 fprintf(stderr, " -k Kill the current agent.\n"); 814 fprintf(stderr, " -d Debug mode.\n"); 815 exit(1); 816 } 817 818 int 819 main(int ac, char **av) 820 { 821 int sock, c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0, ch, nalloc; 822 struct sockaddr_un sunaddr; 823 struct rlimit rlim; 824 pid_t pid; 825 char *shell, *format, *pidstr, pidstrbuf[1 + 3 * sizeof pid]; 826 extern int optind; 827 fd_set *readsetp = NULL, *writesetp = NULL; 828 829 SSLeay_add_all_algorithms(); 830 831 while ((ch = getopt(ac, av, "cdks")) != -1) { 832 switch (ch) { 833 case 'c': 834 if (s_flag) 835 usage(); 836 c_flag++; 837 break; 838 case 'k': 839 k_flag++; 840 break; 841 case 's': 842 if (c_flag) 843 usage(); 844 s_flag++; 845 break; 846 case 'd': 847 if (d_flag) 848 usage(); 849 d_flag++; 850 break; 851 default: 852 usage(); 853 } 854 } 855 ac -= optind; 856 av += optind; 857 858 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag)) 859 usage(); 860 861 if (ac == 0 && !c_flag && !k_flag && !s_flag && !d_flag) { 862 shell = getenv("SHELL"); 863 if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0) 864 c_flag = 1; 865 } 866 if (k_flag) { 867 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 868 if (pidstr == NULL) { 869 fprintf(stderr, "%s not set, cannot kill agent\n", 870 SSH_AGENTPID_ENV_NAME); 871 exit(1); 872 } 873 pid = atoi(pidstr); 874 if (pid < 1) { 875 fprintf(stderr, "%s=\"%s\", which is not a good PID\n", 876 SSH_AGENTPID_ENV_NAME, pidstr); 877 exit(1); 878 } 879 if (kill(pid, SIGTERM) == -1) { 880 perror("kill"); 881 exit(1); 882 } 883 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 884 printf(format, SSH_AUTHSOCKET_ENV_NAME); 885 printf(format, SSH_AGENTPID_ENV_NAME); 886 printf("echo Agent pid %d killed;\n", pid); 887 exit(0); 888 } 889 parent_pid = getpid(); 890 891 /* Create private directory for agent socket */ 892 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXX", sizeof socket_dir); 893 if (mkdtemp(socket_dir) == NULL) { 894 perror("mkdtemp: private socket dir"); 895 exit(1); 896 } 897 snprintf(socket_name, sizeof socket_name, "%s/agent.%d", socket_dir, 898 parent_pid); 899 900 /* 901 * Create socket early so it will exist before command gets run from 902 * the parent. 903 */ 904 sock = socket(AF_UNIX, SOCK_STREAM, 0); 905 if (sock < 0) { 906 perror("socket"); 907 cleanup_exit(1); 908 } 909 memset(&sunaddr, 0, sizeof(sunaddr)); 910 sunaddr.sun_family = AF_UNIX; 911 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); 912 sunaddr.sun_len = SUN_LEN(&sunaddr) + 1; 913 if (bind(sock, (struct sockaddr *)&sunaddr, sunaddr.sun_len) < 0) { 914 perror("bind"); 915 cleanup_exit(1); 916 } 917 if (listen(sock, 5) < 0) { 918 perror("listen"); 919 cleanup_exit(1); 920 } 921 922 /* 923 * Fork, and have the parent execute the command, if any, or present 924 * the socket data. The child continues as the authentication agent. 925 */ 926 if (d_flag) { 927 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1); 928 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 929 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 930 SSH_AUTHSOCKET_ENV_NAME); 931 printf("echo Agent pid %d;\n", parent_pid); 932 goto skip; 933 } 934 pid = fork(); 935 if (pid == -1) { 936 perror("fork"); 937 cleanup_exit(1); 938 } 939 if (pid != 0) { /* Parent - execute the given command. */ 940 close(sock); 941 snprintf(pidstrbuf, sizeof pidstrbuf, "%d", pid); 942 if (ac == 0) { 943 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 944 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 945 SSH_AUTHSOCKET_ENV_NAME); 946 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 947 SSH_AGENTPID_ENV_NAME); 948 printf("echo Agent pid %d;\n", pid); 949 exit(0); 950 } 951 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 952 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 953 perror("setenv"); 954 exit(1); 955 } 956 execvp(av[0], av); 957 perror(av[0]); 958 exit(1); 959 } 960 /* child */ 961 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 962 963 if (setsid() == -1) { 964 error("setsid: %s", strerror(errno)); 965 cleanup_exit(1); 966 } 967 968 (void)chdir("/"); 969 close(0); 970 close(1); 971 close(2); 972 973 /* deny core dumps, since memory contains unencrypted private keys */ 974 rlim.rlim_cur = rlim.rlim_max = 0; 975 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 976 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 977 cleanup_exit(1); 978 } 979 980 skip: 981 fatal_add_cleanup(cleanup_socket, NULL); 982 new_socket(AUTH_SOCKET, sock); 983 if (ac > 0) { 984 signal(SIGALRM, check_parent_exists); 985 alarm(10); 986 } 987 idtab_init(); 988 if (!d_flag) 989 signal(SIGINT, SIG_IGN); 990 signal(SIGPIPE, SIG_IGN); 991 signal(SIGHUP, cleanup_handler); 992 signal(SIGTERM, cleanup_handler); 993 nalloc = 0; 994 995 while (1) { 996 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc); 997 if (select(max_fd + 1, readsetp, writesetp, NULL, NULL) < 0) { 998 if (errno == EINTR) 999 continue; 1000 fatal("select: %s", strerror(errno)); 1001 } 1002 after_select(readsetp, writesetp); 1003 } 1004 /* NOTREACHED */ 1005 } 1006