1 /* $OpenBSD: ssh-agent.c,v 1.77 2001/12/29 21:56:01 stevesk Exp $ */ 2 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("$OpenBSD: ssh-agent.c,v 1.77 2001/12/29 21:56:01 stevesk Exp $"); 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 "packet.h" 50 #include "getput.h" 51 #include "mpaux.h" 52 #include "key.h" 53 #include "authfd.h" 54 #include "cipher.h" 55 #include "kex.h" 56 #include "compat.h" 57 #include "log.h" 58 59 #ifdef SMARTCARD 60 #include <openssl/engine.h> 61 #include "scard.h" 62 #endif 63 64 typedef enum { 65 AUTH_UNUSED, 66 AUTH_SOCKET, 67 AUTH_CONNECTION 68 } sock_type; 69 70 typedef struct { 71 int fd; 72 sock_type type; 73 Buffer input; 74 Buffer output; 75 } SocketEntry; 76 77 u_int sockets_alloc = 0; 78 SocketEntry *sockets = NULL; 79 80 typedef struct { 81 Key *key; 82 char *comment; 83 } Identity; 84 85 typedef struct { 86 int nentries; 87 Identity *identities; 88 } Idtab; 89 90 /* private key table, one per protocol version */ 91 Idtab idtable[3]; 92 93 int max_fd = 0; 94 95 /* pid of shell == parent of agent */ 96 pid_t parent_pid = -1; 97 98 /* pathname and directory for AUTH_SOCKET */ 99 char socket_name[1024]; 100 char socket_dir[1024]; 101 102 extern char *__progname; 103 104 static void 105 idtab_init(void) 106 { 107 int i; 108 for (i = 0; i <=2; i++) { 109 idtable[i].identities = NULL; 110 idtable[i].nentries = 0; 111 } 112 } 113 114 /* return private key table for requested protocol version */ 115 static Idtab * 116 idtab_lookup(int version) 117 { 118 if (version < 1 || version > 2) 119 fatal("internal error, bad protocol version %d", version); 120 return &idtable[version]; 121 } 122 123 /* return matching private key for given public key */ 124 static Key * 125 lookup_private_key(Key *key, int *idx, int version) 126 { 127 int i; 128 Idtab *tab = idtab_lookup(version); 129 for (i = 0; i < tab->nentries; i++) { 130 if (key_equal(key, tab->identities[i].key)) { 131 if (idx != NULL) 132 *idx = i; 133 return tab->identities[i].key; 134 } 135 } 136 return NULL; 137 } 138 139 /* send list of supported public keys to 'client' */ 140 static void 141 process_request_identities(SocketEntry *e, int version) 142 { 143 Idtab *tab = idtab_lookup(version); 144 Buffer msg; 145 int i; 146 147 buffer_init(&msg); 148 buffer_put_char(&msg, (version == 1) ? 149 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 150 buffer_put_int(&msg, tab->nentries); 151 for (i = 0; i < tab->nentries; i++) { 152 Identity *id = &tab->identities[i]; 153 if (id->key->type == KEY_RSA1) { 154 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n)); 155 buffer_put_bignum(&msg, id->key->rsa->e); 156 buffer_put_bignum(&msg, id->key->rsa->n); 157 } else { 158 u_char *blob; 159 u_int blen; 160 key_to_blob(id->key, &blob, &blen); 161 buffer_put_string(&msg, blob, blen); 162 xfree(blob); 163 } 164 buffer_put_cstring(&msg, id->comment); 165 } 166 buffer_put_int(&e->output, buffer_len(&msg)); 167 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 168 buffer_free(&msg); 169 } 170 171 /* ssh1 only */ 172 static void 173 process_authentication_challenge1(SocketEntry *e) 174 { 175 Key *key, *private; 176 BIGNUM *challenge; 177 int i, len; 178 Buffer msg; 179 MD5_CTX md; 180 u_char buf[32], mdbuf[16], session_id[16]; 181 u_int response_type; 182 183 buffer_init(&msg); 184 key = key_new(KEY_RSA1); 185 if ((challenge = BN_new()) == NULL) 186 fatal("process_authentication_challenge1: BN_new failed"); 187 188 buffer_get_int(&e->input); /* ignored */ 189 buffer_get_bignum(&e->input, key->rsa->e); 190 buffer_get_bignum(&e->input, key->rsa->n); 191 buffer_get_bignum(&e->input, challenge); 192 193 /* Only protocol 1.1 is supported */ 194 if (buffer_len(&e->input) == 0) 195 goto failure; 196 buffer_get(&e->input, (char *) session_id, 16); 197 response_type = buffer_get_int(&e->input); 198 if (response_type != 1) 199 goto failure; 200 201 private = lookup_private_key(key, NULL, 1); 202 if (private != NULL) { 203 /* Decrypt the challenge using the private key. */ 204 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0) 205 goto failure; 206 207 /* The response is MD5 of decrypted challenge plus session id. */ 208 len = BN_num_bytes(challenge); 209 if (len <= 0 || len > 32) { 210 log("process_authentication_challenge: bad challenge length %d", len); 211 goto failure; 212 } 213 memset(buf, 0, 32); 214 BN_bn2bin(challenge, buf + 32 - len); 215 MD5_Init(&md); 216 MD5_Update(&md, buf, 32); 217 MD5_Update(&md, session_id, 16); 218 MD5_Final(mdbuf, &md); 219 220 /* Send the response. */ 221 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE); 222 for (i = 0; i < 16; i++) 223 buffer_put_char(&msg, mdbuf[i]); 224 goto send; 225 } 226 227 failure: 228 /* Unknown identity or protocol error. Send failure. */ 229 buffer_put_char(&msg, SSH_AGENT_FAILURE); 230 send: 231 buffer_put_int(&e->output, buffer_len(&msg)); 232 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 233 key_free(key); 234 BN_clear_free(challenge); 235 buffer_free(&msg); 236 } 237 238 /* ssh2 only */ 239 static void 240 process_sign_request2(SocketEntry *e) 241 { 242 extern int datafellows; 243 Key *key, *private; 244 u_char *blob, *data, *signature = NULL; 245 u_int blen, dlen, slen = 0; 246 int flags; 247 Buffer msg; 248 int ok = -1; 249 250 datafellows = 0; 251 252 blob = buffer_get_string(&e->input, &blen); 253 data = buffer_get_string(&e->input, &dlen); 254 255 flags = buffer_get_int(&e->input); 256 if (flags & SSH_AGENT_OLD_SIGNATURE) 257 datafellows = SSH_BUG_SIGBLOB; 258 259 key = key_from_blob(blob, blen); 260 if (key != NULL) { 261 private = lookup_private_key(key, NULL, 2); 262 if (private != NULL) 263 ok = key_sign(private, &signature, &slen, data, dlen); 264 } 265 key_free(key); 266 buffer_init(&msg); 267 if (ok == 0) { 268 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); 269 buffer_put_string(&msg, signature, slen); 270 } else { 271 buffer_put_char(&msg, SSH_AGENT_FAILURE); 272 } 273 buffer_put_int(&e->output, buffer_len(&msg)); 274 buffer_append(&e->output, buffer_ptr(&msg), 275 buffer_len(&msg)); 276 buffer_free(&msg); 277 xfree(data); 278 xfree(blob); 279 if (signature != NULL) 280 xfree(signature); 281 } 282 283 /* shared */ 284 static void 285 process_remove_identity(SocketEntry *e, int version) 286 { 287 Key *key = NULL, *private; 288 u_char *blob; 289 u_int blen; 290 u_int bits; 291 int success = 0; 292 293 switch (version) { 294 case 1: 295 key = key_new(KEY_RSA1); 296 bits = buffer_get_int(&e->input); 297 buffer_get_bignum(&e->input, key->rsa->e); 298 buffer_get_bignum(&e->input, key->rsa->n); 299 300 if (bits != key_size(key)) 301 log("Warning: identity keysize mismatch: actual %d, announced %d", 302 key_size(key), bits); 303 break; 304 case 2: 305 blob = buffer_get_string(&e->input, &blen); 306 key = key_from_blob(blob, blen); 307 xfree(blob); 308 break; 309 } 310 if (key != NULL) { 311 int idx; 312 private = lookup_private_key(key, &idx, version); 313 if (private != NULL) { 314 /* 315 * We have this key. Free the old key. Since we 316 * don\'t want to leave empty slots in the middle of 317 * the array, we actually free the key there and move 318 * all the entries between the empty slot and the end 319 * of the array. 320 */ 321 Idtab *tab = idtab_lookup(version); 322 key_free(tab->identities[idx].key); 323 xfree(tab->identities[idx].comment); 324 if (tab->nentries < 1) 325 fatal("process_remove_identity: " 326 "internal error: tab->nentries %d", 327 tab->nentries); 328 if (idx != tab->nentries - 1) { 329 int i; 330 for (i = idx; i < tab->nentries - 1; i++) 331 tab->identities[i] = tab->identities[i+1]; 332 } 333 tab->identities[tab->nentries - 1].key = NULL; 334 tab->identities[tab->nentries - 1].comment = NULL; 335 tab->nentries--; 336 success = 1; 337 } 338 key_free(key); 339 } 340 buffer_put_int(&e->output, 1); 341 buffer_put_char(&e->output, 342 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 343 } 344 345 static void 346 process_remove_all_identities(SocketEntry *e, int version) 347 { 348 u_int i; 349 Idtab *tab = idtab_lookup(version); 350 351 /* Loop over all identities and clear the keys. */ 352 for (i = 0; i < tab->nentries; i++) { 353 key_free(tab->identities[i].key); 354 xfree(tab->identities[i].comment); 355 } 356 357 /* Mark that there are no identities. */ 358 tab->nentries = 0; 359 360 /* Send success. */ 361 buffer_put_int(&e->output, 1); 362 buffer_put_char(&e->output, SSH_AGENT_SUCCESS); 363 return; 364 } 365 366 static void 367 process_add_identity(SocketEntry *e, int version) 368 { 369 Key *k = NULL; 370 char *type_name; 371 char *comment; 372 int type, success = 0; 373 Idtab *tab = idtab_lookup(version); 374 375 switch (version) { 376 case 1: 377 k = key_new_private(KEY_RSA1); 378 buffer_get_int(&e->input); /* ignored */ 379 buffer_get_bignum(&e->input, k->rsa->n); 380 buffer_get_bignum(&e->input, k->rsa->e); 381 buffer_get_bignum(&e->input, k->rsa->d); 382 buffer_get_bignum(&e->input, k->rsa->iqmp); 383 384 /* SSH and SSL have p and q swapped */ 385 buffer_get_bignum(&e->input, k->rsa->q); /* p */ 386 buffer_get_bignum(&e->input, k->rsa->p); /* q */ 387 388 /* Generate additional parameters */ 389 rsa_generate_additional_parameters(k->rsa); 390 break; 391 case 2: 392 type_name = buffer_get_string(&e->input, NULL); 393 type = key_type_from_name(type_name); 394 xfree(type_name); 395 switch (type) { 396 case KEY_DSA: 397 k = key_new_private(type); 398 buffer_get_bignum2(&e->input, k->dsa->p); 399 buffer_get_bignum2(&e->input, k->dsa->q); 400 buffer_get_bignum2(&e->input, k->dsa->g); 401 buffer_get_bignum2(&e->input, k->dsa->pub_key); 402 buffer_get_bignum2(&e->input, k->dsa->priv_key); 403 break; 404 case KEY_RSA: 405 k = key_new_private(type); 406 buffer_get_bignum2(&e->input, k->rsa->n); 407 buffer_get_bignum2(&e->input, k->rsa->e); 408 buffer_get_bignum2(&e->input, k->rsa->d); 409 buffer_get_bignum2(&e->input, k->rsa->iqmp); 410 buffer_get_bignum2(&e->input, k->rsa->p); 411 buffer_get_bignum2(&e->input, k->rsa->q); 412 413 /* Generate additional parameters */ 414 rsa_generate_additional_parameters(k->rsa); 415 break; 416 default: 417 buffer_clear(&e->input); 418 goto send; 419 } 420 break; 421 } 422 comment = buffer_get_string(&e->input, NULL); 423 if (k == NULL) { 424 xfree(comment); 425 goto send; 426 } 427 success = 1; 428 if (lookup_private_key(k, NULL, version) == NULL) { 429 if (tab->nentries == 0) 430 tab->identities = xmalloc(sizeof(Identity)); 431 else 432 tab->identities = xrealloc(tab->identities, 433 (tab->nentries + 1) * sizeof(Identity)); 434 tab->identities[tab->nentries].key = k; 435 tab->identities[tab->nentries].comment = comment; 436 /* Increment the number of identities. */ 437 tab->nentries++; 438 } else { 439 key_free(k); 440 xfree(comment); 441 } 442 send: 443 buffer_put_int(&e->output, 1); 444 buffer_put_char(&e->output, 445 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 446 } 447 448 449 #ifdef SMARTCARD 450 static void 451 process_add_smartcard_key (SocketEntry *e) 452 { 453 Idtab *tab; 454 Key *n = NULL, *k = NULL; 455 char *sc_reader_id = NULL; 456 int success = 0; 457 458 sc_reader_id = buffer_get_string(&e->input, NULL); 459 k = sc_get_key(sc_reader_id); 460 xfree(sc_reader_id); 461 462 if (k == NULL) { 463 error("sc_get_pubkey failed"); 464 goto send; 465 } 466 success = 1; 467 468 tab = idtab_lookup(1); 469 k->type = KEY_RSA1; 470 if (lookup_private_key(k, NULL, 1) == NULL) { 471 if (tab->nentries == 0) 472 tab->identities = xmalloc(sizeof(Identity)); 473 else 474 tab->identities = xrealloc(tab->identities, 475 (tab->nentries + 1) * sizeof(Identity)); 476 n = key_new(KEY_RSA1); 477 BN_copy(n->rsa->n, k->rsa->n); 478 BN_copy(n->rsa->e, k->rsa->e); 479 RSA_set_method(n->rsa, sc_get_engine()); 480 tab->identities[tab->nentries].key = n; 481 tab->identities[tab->nentries].comment = 482 xstrdup("rsa1 smartcard"); 483 tab->nentries++; 484 } 485 k->type = KEY_RSA; 486 tab = idtab_lookup(2); 487 if (lookup_private_key(k, NULL, 2) == NULL) { 488 if (tab->nentries == 0) 489 tab->identities = xmalloc(sizeof(Identity)); 490 else 491 tab->identities = xrealloc(tab->identities, 492 (tab->nentries + 1) * sizeof(Identity)); 493 n = key_new(KEY_RSA); 494 BN_copy(n->rsa->n, k->rsa->n); 495 BN_copy(n->rsa->e, k->rsa->e); 496 RSA_set_method(n->rsa, sc_get_engine()); 497 tab->identities[tab->nentries].key = n; 498 tab->identities[tab->nentries].comment = 499 xstrdup("rsa smartcard"); 500 tab->nentries++; 501 } 502 key_free(k); 503 send: 504 buffer_put_int(&e->output, 1); 505 buffer_put_char(&e->output, 506 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 507 } 508 509 static void 510 process_remove_smartcard_key(SocketEntry *e) 511 { 512 Key *k = NULL, *private; 513 int idx; 514 int success = 0; 515 char *sc_reader_id = NULL; 516 517 sc_reader_id = buffer_get_string(&e->input, NULL); 518 k = sc_get_key(sc_reader_id); 519 xfree(sc_reader_id); 520 521 if (k == NULL) { 522 error("sc_get_pubkey failed"); 523 } else { 524 k->type = KEY_RSA1; 525 private = lookup_private_key(k, &idx, 1); 526 if (private != NULL) { 527 Idtab *tab = idtab_lookup(1); 528 key_free(tab->identities[idx].key); 529 xfree(tab->identities[idx].comment); 530 if (idx != tab->nentries) 531 tab->identities[idx] = tab->identities[tab->nentries]; 532 tab->nentries--; 533 success = 1; 534 } 535 k->type = KEY_RSA; 536 private = lookup_private_key(k, &idx, 2); 537 if (private != NULL) { 538 Idtab *tab = idtab_lookup(2); 539 key_free(tab->identities[idx].key); 540 xfree(tab->identities[idx].comment); 541 if (idx != tab->nentries) 542 tab->identities[idx] = tab->identities[tab->nentries]; 543 tab->nentries--; 544 success = 1; 545 } 546 key_free(k); 547 } 548 549 buffer_put_int(&e->output, 1); 550 buffer_put_char(&e->output, 551 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 552 } 553 #endif /* SMARTCARD */ 554 555 /* dispatch incoming messages */ 556 557 static void 558 process_message(SocketEntry *e) 559 { 560 u_int msg_len; 561 u_int type; 562 u_char *cp; 563 if (buffer_len(&e->input) < 5) 564 return; /* Incomplete message. */ 565 cp = buffer_ptr(&e->input); 566 msg_len = GET_32BIT(cp); 567 if (msg_len > 256 * 1024) { 568 shutdown(e->fd, SHUT_RDWR); 569 close(e->fd); 570 e->type = AUTH_UNUSED; 571 return; 572 } 573 if (buffer_len(&e->input) < msg_len + 4) 574 return; 575 buffer_consume(&e->input, 4); 576 type = buffer_get_char(&e->input); 577 578 debug("type %d", type); 579 switch (type) { 580 /* ssh1 */ 581 case SSH_AGENTC_RSA_CHALLENGE: 582 process_authentication_challenge1(e); 583 break; 584 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 585 process_request_identities(e, 1); 586 break; 587 case SSH_AGENTC_ADD_RSA_IDENTITY: 588 process_add_identity(e, 1); 589 break; 590 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 591 process_remove_identity(e, 1); 592 break; 593 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 594 process_remove_all_identities(e, 1); 595 break; 596 /* ssh2 */ 597 case SSH2_AGENTC_SIGN_REQUEST: 598 process_sign_request2(e); 599 break; 600 case SSH2_AGENTC_REQUEST_IDENTITIES: 601 process_request_identities(e, 2); 602 break; 603 case SSH2_AGENTC_ADD_IDENTITY: 604 process_add_identity(e, 2); 605 break; 606 case SSH2_AGENTC_REMOVE_IDENTITY: 607 process_remove_identity(e, 2); 608 break; 609 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 610 process_remove_all_identities(e, 2); 611 break; 612 #ifdef SMARTCARD 613 case SSH_AGENTC_ADD_SMARTCARD_KEY: 614 process_add_smartcard_key(e); 615 break; 616 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 617 process_remove_smartcard_key(e); 618 break; 619 #endif /* SMARTCARD */ 620 default: 621 /* Unknown message. Respond with failure. */ 622 error("Unknown message %d", type); 623 buffer_clear(&e->input); 624 buffer_put_int(&e->output, 1); 625 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 626 break; 627 } 628 } 629 630 static void 631 new_socket(sock_type type, int fd) 632 { 633 u_int i, old_alloc; 634 if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) 635 error("fcntl O_NONBLOCK: %s", strerror(errno)); 636 637 if (fd > max_fd) 638 max_fd = fd; 639 640 for (i = 0; i < sockets_alloc; i++) 641 if (sockets[i].type == AUTH_UNUSED) { 642 sockets[i].fd = fd; 643 sockets[i].type = type; 644 buffer_init(&sockets[i].input); 645 buffer_init(&sockets[i].output); 646 return; 647 } 648 old_alloc = sockets_alloc; 649 sockets_alloc += 10; 650 if (sockets) 651 sockets = xrealloc(sockets, sockets_alloc * sizeof(sockets[0])); 652 else 653 sockets = xmalloc(sockets_alloc * sizeof(sockets[0])); 654 for (i = old_alloc; i < sockets_alloc; i++) 655 sockets[i].type = AUTH_UNUSED; 656 sockets[old_alloc].type = type; 657 sockets[old_alloc].fd = fd; 658 buffer_init(&sockets[old_alloc].input); 659 buffer_init(&sockets[old_alloc].output); 660 } 661 662 static int 663 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, int *nallocp) 664 { 665 u_int i, sz; 666 int n = 0; 667 668 for (i = 0; i < sockets_alloc; i++) { 669 switch (sockets[i].type) { 670 case AUTH_SOCKET: 671 case AUTH_CONNECTION: 672 n = MAX(n, sockets[i].fd); 673 break; 674 case AUTH_UNUSED: 675 break; 676 default: 677 fatal("Unknown socket type %d", sockets[i].type); 678 break; 679 } 680 } 681 682 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 683 if (*fdrp == NULL || sz > *nallocp) { 684 if (*fdrp) 685 xfree(*fdrp); 686 if (*fdwp) 687 xfree(*fdwp); 688 *fdrp = xmalloc(sz); 689 *fdwp = xmalloc(sz); 690 *nallocp = sz; 691 } 692 if (n < *fdl) 693 debug("XXX shrink: %d < %d", n, *fdl); 694 *fdl = n; 695 memset(*fdrp, 0, sz); 696 memset(*fdwp, 0, sz); 697 698 for (i = 0; i < sockets_alloc; i++) { 699 switch (sockets[i].type) { 700 case AUTH_SOCKET: 701 case AUTH_CONNECTION: 702 FD_SET(sockets[i].fd, *fdrp); 703 if (buffer_len(&sockets[i].output) > 0) 704 FD_SET(sockets[i].fd, *fdwp); 705 break; 706 default: 707 break; 708 } 709 } 710 return (1); 711 } 712 713 static void 714 after_select(fd_set *readset, fd_set *writeset) 715 { 716 u_int i; 717 int len, sock; 718 socklen_t slen; 719 char buf[1024]; 720 struct sockaddr_un sunaddr; 721 722 for (i = 0; i < sockets_alloc; i++) 723 switch (sockets[i].type) { 724 case AUTH_UNUSED: 725 break; 726 case AUTH_SOCKET: 727 if (FD_ISSET(sockets[i].fd, readset)) { 728 slen = sizeof(sunaddr); 729 sock = accept(sockets[i].fd, 730 (struct sockaddr *) &sunaddr, &slen); 731 if (sock < 0) { 732 perror("accept from AUTH_SOCKET"); 733 break; 734 } 735 new_socket(AUTH_CONNECTION, sock); 736 } 737 break; 738 case AUTH_CONNECTION: 739 if (buffer_len(&sockets[i].output) > 0 && 740 FD_ISSET(sockets[i].fd, writeset)) { 741 do { 742 len = write(sockets[i].fd, 743 buffer_ptr(&sockets[i].output), 744 buffer_len(&sockets[i].output)); 745 if (len == -1 && (errno == EAGAIN || 746 errno == EINTR)) 747 continue; 748 break; 749 } while (1); 750 if (len <= 0) { 751 shutdown(sockets[i].fd, SHUT_RDWR); 752 close(sockets[i].fd); 753 sockets[i].type = AUTH_UNUSED; 754 buffer_free(&sockets[i].input); 755 buffer_free(&sockets[i].output); 756 break; 757 } 758 buffer_consume(&sockets[i].output, len); 759 } 760 if (FD_ISSET(sockets[i].fd, readset)) { 761 do { 762 len = read(sockets[i].fd, buf, sizeof(buf)); 763 if (len == -1 && (errno == EAGAIN || 764 errno == EINTR)) 765 continue; 766 break; 767 } while (1); 768 if (len <= 0) { 769 shutdown(sockets[i].fd, SHUT_RDWR); 770 close(sockets[i].fd); 771 sockets[i].type = AUTH_UNUSED; 772 buffer_free(&sockets[i].input); 773 buffer_free(&sockets[i].output); 774 break; 775 } 776 buffer_append(&sockets[i].input, buf, len); 777 process_message(&sockets[i]); 778 } 779 break; 780 default: 781 fatal("Unknown type %d", sockets[i].type); 782 } 783 } 784 785 static void 786 cleanup_socket(void) 787 { 788 if (socket_name[0]) 789 unlink(socket_name); 790 if (socket_dir[0]) 791 rmdir(socket_dir); 792 } 793 794 static void 795 cleanup_exit(int i) 796 { 797 cleanup_socket(); 798 exit(i); 799 } 800 801 static void 802 cleanup_handler(int sig) 803 { 804 cleanup_socket(); 805 _exit(2); 806 } 807 808 static void 809 check_parent_exists(int sig) 810 { 811 int save_errno = errno; 812 813 if (parent_pid != -1 && kill(parent_pid, 0) < 0) { 814 /* printf("Parent has died - Authentication agent exiting.\n"); */ 815 cleanup_handler(sig); /* safe */ 816 } 817 signal(SIGALRM, check_parent_exists); 818 alarm(10); 819 errno = save_errno; 820 } 821 822 static void 823 usage(void) 824 { 825 fprintf(stderr, "Usage: %s [options] [command [args ...]]\n", 826 __progname); 827 fprintf(stderr, "Options:\n"); 828 fprintf(stderr, " -c Generate C-shell commands on stdout.\n"); 829 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n"); 830 fprintf(stderr, " -k Kill the current agent.\n"); 831 fprintf(stderr, " -d Debug mode.\n"); 832 exit(1); 833 } 834 835 int 836 main(int ac, char **av) 837 { 838 int sock, c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0, ch, nalloc; 839 struct sockaddr_un sunaddr; 840 struct rlimit rlim; 841 pid_t pid; 842 char *shell, *format, *pidstr, pidstrbuf[1 + 3 * sizeof pid]; 843 extern int optind; 844 fd_set *readsetp = NULL, *writesetp = NULL; 845 846 SSLeay_add_all_algorithms(); 847 848 while ((ch = getopt(ac, av, "cdks")) != -1) { 849 switch (ch) { 850 case 'c': 851 if (s_flag) 852 usage(); 853 c_flag++; 854 break; 855 case 'k': 856 k_flag++; 857 break; 858 case 's': 859 if (c_flag) 860 usage(); 861 s_flag++; 862 break; 863 case 'd': 864 if (d_flag) 865 usage(); 866 d_flag++; 867 break; 868 default: 869 usage(); 870 } 871 } 872 ac -= optind; 873 av += optind; 874 875 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag)) 876 usage(); 877 878 if (ac == 0 && !c_flag && !k_flag && !s_flag && !d_flag) { 879 shell = getenv("SHELL"); 880 if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0) 881 c_flag = 1; 882 } 883 if (k_flag) { 884 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 885 if (pidstr == NULL) { 886 fprintf(stderr, "%s not set, cannot kill agent\n", 887 SSH_AGENTPID_ENV_NAME); 888 exit(1); 889 } 890 pid = atoi(pidstr); 891 if (pid < 1) { 892 fprintf(stderr, "%s=\"%s\", which is not a good PID\n", 893 SSH_AGENTPID_ENV_NAME, pidstr); 894 exit(1); 895 } 896 if (kill(pid, SIGTERM) == -1) { 897 perror("kill"); 898 exit(1); 899 } 900 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 901 printf(format, SSH_AUTHSOCKET_ENV_NAME); 902 printf(format, SSH_AGENTPID_ENV_NAME); 903 printf("echo Agent pid %d killed;\n", pid); 904 exit(0); 905 } 906 parent_pid = getpid(); 907 908 /* Create private directory for agent socket */ 909 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXX", sizeof socket_dir); 910 if (mkdtemp(socket_dir) == NULL) { 911 perror("mkdtemp: private socket dir"); 912 exit(1); 913 } 914 snprintf(socket_name, sizeof socket_name, "%s/agent.%d", socket_dir, 915 parent_pid); 916 917 /* 918 * Create socket early so it will exist before command gets run from 919 * the parent. 920 */ 921 sock = socket(AF_UNIX, SOCK_STREAM, 0); 922 if (sock < 0) { 923 perror("socket"); 924 cleanup_exit(1); 925 } 926 memset(&sunaddr, 0, sizeof(sunaddr)); 927 sunaddr.sun_family = AF_UNIX; 928 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); 929 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) { 930 perror("bind"); 931 cleanup_exit(1); 932 } 933 if (listen(sock, 5) < 0) { 934 perror("listen"); 935 cleanup_exit(1); 936 } 937 938 /* 939 * Fork, and have the parent execute the command, if any, or present 940 * the socket data. The child continues as the authentication agent. 941 */ 942 if (d_flag) { 943 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1); 944 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 945 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 946 SSH_AUTHSOCKET_ENV_NAME); 947 printf("echo Agent pid %d;\n", parent_pid); 948 goto skip; 949 } 950 pid = fork(); 951 if (pid == -1) { 952 perror("fork"); 953 exit(1); 954 } 955 if (pid != 0) { /* Parent - execute the given command. */ 956 close(sock); 957 snprintf(pidstrbuf, sizeof pidstrbuf, "%d", pid); 958 if (ac == 0) { 959 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 960 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 961 SSH_AUTHSOCKET_ENV_NAME); 962 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 963 SSH_AGENTPID_ENV_NAME); 964 printf("echo Agent pid %d;\n", pid); 965 exit(0); 966 } 967 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 968 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 969 perror("setenv"); 970 exit(1); 971 } 972 execvp(av[0], av); 973 perror(av[0]); 974 exit(1); 975 } 976 977 if (setsid() == -1) { 978 perror("setsid"); 979 cleanup_exit(1); 980 } 981 982 (void)chdir("/"); 983 close(0); 984 close(1); 985 close(2); 986 987 /* deny core dumps, since memory contains unencrypted private keys */ 988 rlim.rlim_cur = rlim.rlim_max = 0; 989 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 990 perror("setrlimit rlimit_core failed"); 991 cleanup_exit(1); 992 } 993 994 skip: 995 if (atexit(cleanup_socket) < 0) { 996 perror("atexit"); 997 cleanup_exit(1); 998 } 999 new_socket(AUTH_SOCKET, sock); 1000 if (ac > 0) { 1001 signal(SIGALRM, check_parent_exists); 1002 alarm(10); 1003 } 1004 idtab_init(); 1005 if (!d_flag) 1006 signal(SIGINT, SIG_IGN); 1007 signal(SIGPIPE, SIG_IGN); 1008 signal(SIGHUP, cleanup_handler); 1009 signal(SIGTERM, cleanup_handler); 1010 nalloc = 0; 1011 1012 while (1) { 1013 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc); 1014 if (select(max_fd + 1, readsetp, writesetp, NULL, NULL) < 0) { 1015 if (errno == EINTR) 1016 continue; 1017 exit(1); 1018 } 1019 after_select(readsetp, writesetp); 1020 } 1021 /* NOTREACHED */ 1022 } 1023