1 /* $OpenBSD: ssh-agent.c,v 1.72 2001/08/03 10:31:30 jakob 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 1.72 2001/08/03 10:31:30 jakob 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 struct { 65 int fd; 66 enum { 67 AUTH_UNUSED, AUTH_SOCKET, AUTH_CONNECTION 68 } type; 69 Buffer input; 70 Buffer output; 71 } SocketEntry; 72 73 u_int sockets_alloc = 0; 74 SocketEntry *sockets = NULL; 75 76 typedef struct { 77 Key *key; 78 char *comment; 79 } Identity; 80 81 typedef struct { 82 int nentries; 83 Identity *identities; 84 } Idtab; 85 86 /* private key table, one per protocol version */ 87 Idtab idtable[3]; 88 89 int max_fd = 0; 90 91 /* pid of shell == parent of agent */ 92 pid_t parent_pid = -1; 93 94 /* pathname and directory for AUTH_SOCKET */ 95 char socket_name[1024]; 96 char socket_dir[1024]; 97 98 extern char *__progname; 99 100 static void 101 idtab_init(void) 102 { 103 int i; 104 for (i = 0; i <=2; i++){ 105 idtable[i].identities = NULL; 106 idtable[i].nentries = 0; 107 } 108 } 109 110 /* return private key table for requested protocol version */ 111 static Idtab * 112 idtab_lookup(int version) 113 { 114 if (version < 1 || version > 2) 115 fatal("internal error, bad protocol version %d", version); 116 return &idtable[version]; 117 } 118 119 /* return matching private key for given public key */ 120 static Key * 121 lookup_private_key(Key *key, int *idx, int version) 122 { 123 int i; 124 Idtab *tab = idtab_lookup(version); 125 for (i = 0; i < tab->nentries; i++) { 126 if (key_equal(key, tab->identities[i].key)) { 127 if (idx != NULL) 128 *idx = i; 129 return tab->identities[i].key; 130 } 131 } 132 return NULL; 133 } 134 135 /* send list of supported public keys to 'client' */ 136 static void 137 process_request_identities(SocketEntry *e, int version) 138 { 139 Idtab *tab = idtab_lookup(version); 140 Buffer msg; 141 int i; 142 143 buffer_init(&msg); 144 buffer_put_char(&msg, (version == 1) ? 145 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 146 buffer_put_int(&msg, tab->nentries); 147 for (i = 0; i < tab->nentries; i++) { 148 Identity *id = &tab->identities[i]; 149 if (id->key->type == KEY_RSA1) { 150 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n)); 151 buffer_put_bignum(&msg, id->key->rsa->e); 152 buffer_put_bignum(&msg, id->key->rsa->n); 153 } else { 154 u_char *blob; 155 u_int blen; 156 key_to_blob(id->key, &blob, &blen); 157 buffer_put_string(&msg, blob, blen); 158 xfree(blob); 159 } 160 buffer_put_cstring(&msg, id->comment); 161 } 162 buffer_put_int(&e->output, buffer_len(&msg)); 163 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 164 buffer_free(&msg); 165 } 166 167 /* ssh1 only */ 168 static void 169 process_authentication_challenge1(SocketEntry *e) 170 { 171 Key *key, *private; 172 BIGNUM *challenge; 173 int i, len; 174 Buffer msg; 175 MD5_CTX md; 176 u_char buf[32], mdbuf[16], session_id[16]; 177 u_int response_type; 178 179 buffer_init(&msg); 180 key = key_new(KEY_RSA1); 181 challenge = BN_new(); 182 183 buffer_get_int(&e->input); /* ignored */ 184 buffer_get_bignum(&e->input, key->rsa->e); 185 buffer_get_bignum(&e->input, key->rsa->n); 186 buffer_get_bignum(&e->input, challenge); 187 188 /* Only protocol 1.1 is supported */ 189 if (buffer_len(&e->input) == 0) 190 goto failure; 191 buffer_get(&e->input, (char *) session_id, 16); 192 response_type = buffer_get_int(&e->input); 193 if (response_type != 1) 194 goto failure; 195 196 private = lookup_private_key(key, NULL, 1); 197 if (private != NULL) { 198 /* Decrypt the challenge using the private key. */ 199 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0) 200 goto failure; 201 202 /* The response is MD5 of decrypted challenge plus session id. */ 203 len = BN_num_bytes(challenge); 204 if (len <= 0 || len > 32) { 205 log("process_authentication_challenge: bad challenge length %d", len); 206 goto failure; 207 } 208 memset(buf, 0, 32); 209 BN_bn2bin(challenge, buf + 32 - len); 210 MD5_Init(&md); 211 MD5_Update(&md, buf, 32); 212 MD5_Update(&md, session_id, 16); 213 MD5_Final(mdbuf, &md); 214 215 /* Send the response. */ 216 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE); 217 for (i = 0; i < 16; i++) 218 buffer_put_char(&msg, mdbuf[i]); 219 goto send; 220 } 221 222 failure: 223 /* Unknown identity or protocol error. Send failure. */ 224 buffer_put_char(&msg, SSH_AGENT_FAILURE); 225 send: 226 buffer_put_int(&e->output, buffer_len(&msg)); 227 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 228 key_free(key); 229 BN_clear_free(challenge); 230 buffer_free(&msg); 231 } 232 233 /* ssh2 only */ 234 static void 235 process_sign_request2(SocketEntry *e) 236 { 237 extern int datafellows; 238 Key *key, *private; 239 u_char *blob, *data, *signature = NULL; 240 u_int blen, dlen, slen = 0; 241 int flags; 242 Buffer msg; 243 int ok = -1; 244 245 datafellows = 0; 246 247 blob = buffer_get_string(&e->input, &blen); 248 data = buffer_get_string(&e->input, &dlen); 249 250 flags = buffer_get_int(&e->input); 251 if (flags & SSH_AGENT_OLD_SIGNATURE) 252 datafellows = SSH_BUG_SIGBLOB; 253 254 key = key_from_blob(blob, blen); 255 if (key != NULL) { 256 private = lookup_private_key(key, NULL, 2); 257 if (private != NULL) 258 ok = key_sign(private, &signature, &slen, data, dlen); 259 } 260 key_free(key); 261 buffer_init(&msg); 262 if (ok == 0) { 263 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); 264 buffer_put_string(&msg, signature, slen); 265 } else { 266 buffer_put_char(&msg, SSH_AGENT_FAILURE); 267 } 268 buffer_put_int(&e->output, buffer_len(&msg)); 269 buffer_append(&e->output, buffer_ptr(&msg), 270 buffer_len(&msg)); 271 buffer_free(&msg); 272 xfree(data); 273 xfree(blob); 274 if (signature != NULL) 275 xfree(signature); 276 } 277 278 /* shared */ 279 static void 280 process_remove_identity(SocketEntry *e, int version) 281 { 282 Key *key = NULL, *private; 283 u_char *blob; 284 u_int blen; 285 u_int bits; 286 int success = 0; 287 288 switch(version){ 289 case 1: 290 key = key_new(KEY_RSA1); 291 bits = buffer_get_int(&e->input); 292 buffer_get_bignum(&e->input, key->rsa->e); 293 buffer_get_bignum(&e->input, key->rsa->n); 294 295 if (bits != key_size(key)) 296 log("Warning: identity keysize mismatch: actual %d, announced %d", 297 key_size(key), bits); 298 break; 299 case 2: 300 blob = buffer_get_string(&e->input, &blen); 301 key = key_from_blob(blob, blen); 302 xfree(blob); 303 break; 304 } 305 if (key != NULL) { 306 int idx; 307 private = lookup_private_key(key, &idx, version); 308 if (private != NULL) { 309 /* 310 * We have this key. Free the old key. Since we 311 * don\'t want to leave empty slots in the middle of 312 * the array, we actually free the key there and move 313 * all the entries between the empty slot and the end 314 * of the array. 315 */ 316 Idtab *tab = idtab_lookup(version); 317 key_free(tab->identities[idx].key); 318 xfree(tab->identities[idx].comment); 319 if (tab->nentries < 1) 320 fatal("process_remove_identity: " 321 "internal error: tab->nentries %d", 322 tab->nentries); 323 if (idx != tab->nentries - 1) { 324 int i; 325 for (i = idx; i < tab->nentries - 1; i++) 326 tab->identities[i] = tab->identities[i+1]; 327 } 328 tab->identities[tab->nentries - 1].key = NULL; 329 tab->identities[tab->nentries - 1].comment = NULL; 330 tab->nentries--; 331 success = 1; 332 } 333 key_free(key); 334 } 335 buffer_put_int(&e->output, 1); 336 buffer_put_char(&e->output, 337 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 338 } 339 340 static void 341 process_remove_all_identities(SocketEntry *e, int version) 342 { 343 u_int i; 344 Idtab *tab = idtab_lookup(version); 345 346 /* Loop over all identities and clear the keys. */ 347 for (i = 0; i < tab->nentries; i++) { 348 key_free(tab->identities[i].key); 349 xfree(tab->identities[i].comment); 350 } 351 352 /* Mark that there are no identities. */ 353 tab->nentries = 0; 354 355 /* Send success. */ 356 buffer_put_int(&e->output, 1); 357 buffer_put_char(&e->output, SSH_AGENT_SUCCESS); 358 return; 359 } 360 361 static void 362 process_add_identity(SocketEntry *e, int version) 363 { 364 Key *k = NULL; 365 char *type_name; 366 char *comment; 367 int type, success = 0; 368 Idtab *tab = idtab_lookup(version); 369 370 switch (version) { 371 case 1: 372 k = key_new_private(KEY_RSA1); 373 buffer_get_int(&e->input); /* ignored */ 374 buffer_get_bignum(&e->input, k->rsa->n); 375 buffer_get_bignum(&e->input, k->rsa->e); 376 buffer_get_bignum(&e->input, k->rsa->d); 377 buffer_get_bignum(&e->input, k->rsa->iqmp); 378 379 /* SSH and SSL have p and q swapped */ 380 buffer_get_bignum(&e->input, k->rsa->q); /* p */ 381 buffer_get_bignum(&e->input, k->rsa->p); /* q */ 382 383 /* Generate additional parameters */ 384 rsa_generate_additional_parameters(k->rsa); 385 break; 386 case 2: 387 type_name = buffer_get_string(&e->input, NULL); 388 type = key_type_from_name(type_name); 389 xfree(type_name); 390 switch(type) { 391 case KEY_DSA: 392 k = key_new_private(type); 393 buffer_get_bignum2(&e->input, k->dsa->p); 394 buffer_get_bignum2(&e->input, k->dsa->q); 395 buffer_get_bignum2(&e->input, k->dsa->g); 396 buffer_get_bignum2(&e->input, k->dsa->pub_key); 397 buffer_get_bignum2(&e->input, k->dsa->priv_key); 398 break; 399 case KEY_RSA: 400 k = key_new_private(type); 401 buffer_get_bignum2(&e->input, k->rsa->n); 402 buffer_get_bignum2(&e->input, k->rsa->e); 403 buffer_get_bignum2(&e->input, k->rsa->d); 404 buffer_get_bignum2(&e->input, k->rsa->iqmp); 405 buffer_get_bignum2(&e->input, k->rsa->p); 406 buffer_get_bignum2(&e->input, k->rsa->q); 407 408 /* Generate additional parameters */ 409 rsa_generate_additional_parameters(k->rsa); 410 break; 411 default: 412 buffer_clear(&e->input); 413 goto send; 414 } 415 break; 416 } 417 comment = buffer_get_string(&e->input, NULL); 418 if (k == NULL) { 419 xfree(comment); 420 goto send; 421 } 422 success = 1; 423 if (lookup_private_key(k, NULL, version) == NULL) { 424 if (tab->nentries == 0) 425 tab->identities = xmalloc(sizeof(Identity)); 426 else 427 tab->identities = xrealloc(tab->identities, 428 (tab->nentries + 1) * sizeof(Identity)); 429 tab->identities[tab->nentries].key = k; 430 tab->identities[tab->nentries].comment = comment; 431 /* Increment the number of identities. */ 432 tab->nentries++; 433 } else { 434 key_free(k); 435 xfree(comment); 436 } 437 send: 438 buffer_put_int(&e->output, 1); 439 buffer_put_char(&e->output, 440 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 441 } 442 443 444 #ifdef SMARTCARD 445 static void 446 process_add_smartcard_key (SocketEntry *e) 447 { 448 Idtab *tab; 449 Key *n = NULL, *k = NULL; 450 char *sc_reader_id = NULL; 451 int success = 0; 452 453 sc_reader_id = buffer_get_string(&e->input, NULL); 454 k = sc_get_key(sc_reader_id); 455 xfree(sc_reader_id); 456 457 if (k == NULL) { 458 error("sc_get_pubkey failed"); 459 goto send; 460 } 461 success = 1; 462 463 tab = idtab_lookup(1); 464 k->type = KEY_RSA1; 465 if (lookup_private_key(k, NULL, 1) == NULL) { 466 if (tab->nentries == 0) 467 tab->identities = xmalloc(sizeof(Identity)); 468 else 469 tab->identities = xrealloc(tab->identities, 470 (tab->nentries + 1) * sizeof(Identity)); 471 n = key_new(KEY_RSA1); 472 BN_copy(n->rsa->n, k->rsa->n); 473 BN_copy(n->rsa->e, k->rsa->e); 474 RSA_set_method(n->rsa, sc_get_engine()); 475 tab->identities[tab->nentries].key = n; 476 tab->identities[tab->nentries].comment = 477 xstrdup("rsa1 smartcard"); 478 tab->nentries++; 479 } 480 k->type = KEY_RSA; 481 tab = idtab_lookup(2); 482 if (lookup_private_key(k, NULL, 2) == NULL) { 483 if (tab->nentries == 0) 484 tab->identities = xmalloc(sizeof(Identity)); 485 else 486 tab->identities = xrealloc(tab->identities, 487 (tab->nentries + 1) * sizeof(Identity)); 488 n = key_new(KEY_RSA); 489 BN_copy(n->rsa->n, k->rsa->n); 490 BN_copy(n->rsa->e, k->rsa->e); 491 RSA_set_method(n->rsa, sc_get_engine()); 492 tab->identities[tab->nentries].key = n; 493 tab->identities[tab->nentries].comment = 494 xstrdup("rsa smartcard"); 495 tab->nentries++; 496 } 497 key_free(k); 498 send: 499 buffer_put_int(&e->output, 1); 500 buffer_put_char(&e->output, 501 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 502 } 503 504 static void 505 process_remove_smartcard_key(SocketEntry *e) 506 { 507 Key *k = NULL, *private; 508 int idx; 509 int success = 0; 510 char *sc_reader_id = NULL; 511 512 sc_reader_id = buffer_get_string(&e->input, NULL); 513 k = sc_get_key(sc_reader_id); 514 xfree(sc_reader_id); 515 516 if (k == NULL) { 517 error("sc_get_pubkey failed"); 518 } else { 519 k->type = KEY_RSA1; 520 private = lookup_private_key(k, &idx, 1); 521 if (private != NULL) { 522 Idtab *tab = idtab_lookup(1); 523 key_free(tab->identities[idx].key); 524 xfree(tab->identities[idx].comment); 525 if (idx != tab->nentries) 526 tab->identities[idx] = tab->identities[tab->nentries]; 527 tab->nentries--; 528 success = 1; 529 } 530 k->type = KEY_RSA; 531 private = lookup_private_key(k, &idx, 2); 532 if (private != NULL) { 533 Idtab *tab = idtab_lookup(2); 534 key_free(tab->identities[idx].key); 535 xfree(tab->identities[idx].comment); 536 if (idx != tab->nentries) 537 tab->identities[idx] = tab->identities[tab->nentries]; 538 tab->nentries--; 539 success = 1; 540 } 541 key_free(k); 542 } 543 544 buffer_put_int(&e->output, 1); 545 buffer_put_char(&e->output, 546 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 547 } 548 #endif /* SMARTCARD */ 549 550 /* dispatch incoming messages */ 551 552 static void 553 process_message(SocketEntry *e) 554 { 555 u_int msg_len; 556 u_int type; 557 u_char *cp; 558 if (buffer_len(&e->input) < 5) 559 return; /* Incomplete message. */ 560 cp = (u_char *) buffer_ptr(&e->input); 561 msg_len = GET_32BIT(cp); 562 if (msg_len > 256 * 1024) { 563 shutdown(e->fd, SHUT_RDWR); 564 close(e->fd); 565 e->type = AUTH_UNUSED; 566 return; 567 } 568 if (buffer_len(&e->input) < msg_len + 4) 569 return; 570 buffer_consume(&e->input, 4); 571 type = buffer_get_char(&e->input); 572 573 debug("type %d", type); 574 switch (type) { 575 /* ssh1 */ 576 case SSH_AGENTC_RSA_CHALLENGE: 577 process_authentication_challenge1(e); 578 break; 579 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 580 process_request_identities(e, 1); 581 break; 582 case SSH_AGENTC_ADD_RSA_IDENTITY: 583 process_add_identity(e, 1); 584 break; 585 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 586 process_remove_identity(e, 1); 587 break; 588 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 589 process_remove_all_identities(e, 1); 590 break; 591 /* ssh2 */ 592 case SSH2_AGENTC_SIGN_REQUEST: 593 process_sign_request2(e); 594 break; 595 case SSH2_AGENTC_REQUEST_IDENTITIES: 596 process_request_identities(e, 2); 597 break; 598 case SSH2_AGENTC_ADD_IDENTITY: 599 process_add_identity(e, 2); 600 break; 601 case SSH2_AGENTC_REMOVE_IDENTITY: 602 process_remove_identity(e, 2); 603 break; 604 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 605 process_remove_all_identities(e, 2); 606 break; 607 #ifdef SMARTCARD 608 case SSH_AGENTC_ADD_SMARTCARD_KEY: 609 process_add_smartcard_key(e); 610 break; 611 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 612 process_remove_smartcard_key(e); 613 break; 614 #endif /* SMARTCARD */ 615 default: 616 /* Unknown message. Respond with failure. */ 617 error("Unknown message %d", type); 618 buffer_clear(&e->input); 619 buffer_put_int(&e->output, 1); 620 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 621 break; 622 } 623 } 624 625 static void 626 new_socket(int type, int fd) 627 { 628 u_int i, old_alloc; 629 if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) 630 error("fcntl O_NONBLOCK: %s", strerror(errno)); 631 632 if (fd > max_fd) 633 max_fd = fd; 634 635 for (i = 0; i < sockets_alloc; i++) 636 if (sockets[i].type == AUTH_UNUSED) { 637 sockets[i].fd = fd; 638 sockets[i].type = type; 639 buffer_init(&sockets[i].input); 640 buffer_init(&sockets[i].output); 641 return; 642 } 643 old_alloc = sockets_alloc; 644 sockets_alloc += 10; 645 if (sockets) 646 sockets = xrealloc(sockets, sockets_alloc * sizeof(sockets[0])); 647 else 648 sockets = xmalloc(sockets_alloc * sizeof(sockets[0])); 649 for (i = old_alloc; i < sockets_alloc; i++) 650 sockets[i].type = AUTH_UNUSED; 651 sockets[old_alloc].type = type; 652 sockets[old_alloc].fd = fd; 653 buffer_init(&sockets[old_alloc].input); 654 buffer_init(&sockets[old_alloc].output); 655 } 656 657 static int 658 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, int *nallocp) 659 { 660 u_int i, sz; 661 int n = 0; 662 663 for (i = 0; i < sockets_alloc; i++) { 664 switch (sockets[i].type) { 665 case AUTH_SOCKET: 666 case AUTH_CONNECTION: 667 n = MAX(n, sockets[i].fd); 668 break; 669 case AUTH_UNUSED: 670 break; 671 default: 672 fatal("Unknown socket type %d", sockets[i].type); 673 break; 674 } 675 } 676 677 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 678 if (*fdrp == NULL || sz > *nallocp) { 679 if (*fdrp) 680 xfree(*fdrp); 681 if (*fdwp) 682 xfree(*fdwp); 683 *fdrp = xmalloc(sz); 684 *fdwp = xmalloc(sz); 685 *nallocp = sz; 686 } 687 if (n < *fdl) 688 debug("XXX shrink: %d < %d", n, *fdl); 689 *fdl = n; 690 memset(*fdrp, 0, sz); 691 memset(*fdwp, 0, sz); 692 693 for (i = 0; i < sockets_alloc; i++) { 694 switch (sockets[i].type) { 695 case AUTH_SOCKET: 696 case AUTH_CONNECTION: 697 FD_SET(sockets[i].fd, *fdrp); 698 if (buffer_len(&sockets[i].output) > 0) 699 FD_SET(sockets[i].fd, *fdwp); 700 break; 701 default: 702 break; 703 } 704 } 705 return (1); 706 } 707 708 static void 709 after_select(fd_set *readset, fd_set *writeset) 710 { 711 u_int i; 712 int len, sock; 713 socklen_t slen; 714 char buf[1024]; 715 struct sockaddr_un sunaddr; 716 717 for (i = 0; i < sockets_alloc; i++) 718 switch (sockets[i].type) { 719 case AUTH_UNUSED: 720 break; 721 case AUTH_SOCKET: 722 if (FD_ISSET(sockets[i].fd, readset)) { 723 slen = sizeof(sunaddr); 724 sock = accept(sockets[i].fd, 725 (struct sockaddr *) &sunaddr, &slen); 726 if (sock < 0) { 727 perror("accept from AUTH_SOCKET"); 728 break; 729 } 730 new_socket(AUTH_CONNECTION, sock); 731 } 732 break; 733 case AUTH_CONNECTION: 734 if (buffer_len(&sockets[i].output) > 0 && 735 FD_ISSET(sockets[i].fd, writeset)) { 736 do { 737 len = write(sockets[i].fd, 738 buffer_ptr(&sockets[i].output), 739 buffer_len(&sockets[i].output)); 740 if (len == -1 && (errno == EAGAIN || 741 errno == EINTR)) 742 continue; 743 break; 744 } while (1); 745 if (len <= 0) { 746 shutdown(sockets[i].fd, SHUT_RDWR); 747 close(sockets[i].fd); 748 sockets[i].type = AUTH_UNUSED; 749 buffer_free(&sockets[i].input); 750 buffer_free(&sockets[i].output); 751 break; 752 } 753 buffer_consume(&sockets[i].output, len); 754 } 755 if (FD_ISSET(sockets[i].fd, readset)) { 756 do { 757 len = read(sockets[i].fd, buf, sizeof(buf)); 758 if (len == -1 && (errno == EAGAIN || 759 errno == EINTR)) 760 continue; 761 break; 762 } while (1); 763 if (len <= 0) { 764 shutdown(sockets[i].fd, SHUT_RDWR); 765 close(sockets[i].fd); 766 sockets[i].type = AUTH_UNUSED; 767 buffer_free(&sockets[i].input); 768 buffer_free(&sockets[i].output); 769 break; 770 } 771 buffer_append(&sockets[i].input, buf, len); 772 process_message(&sockets[i]); 773 } 774 break; 775 default: 776 fatal("Unknown type %d", sockets[i].type); 777 } 778 } 779 780 static void 781 cleanup_socket(void) 782 { 783 if (socket_name[0]) 784 unlink(socket_name); 785 if (socket_dir[0]) 786 rmdir(socket_dir); 787 } 788 789 static void 790 cleanup_exit(int i) 791 { 792 cleanup_socket(); 793 exit(i); 794 } 795 796 static void 797 cleanup_handler(int sig) 798 { 799 cleanup_socket(); 800 _exit(2); 801 } 802 803 static void 804 check_parent_exists(int sig) 805 { 806 int save_errno = errno; 807 808 if (parent_pid != -1 && kill(parent_pid, 0) < 0) { 809 /* printf("Parent has died - Authentication agent exiting.\n"); */ 810 cleanup_handler(sig); /* safe */ 811 } 812 signal(SIGALRM, check_parent_exists); 813 alarm(10); 814 errno = save_errno; 815 } 816 817 static void 818 usage(void) 819 { 820 fprintf(stderr, "Usage: %s [options] [command [args ...]]\n", 821 __progname); 822 fprintf(stderr, "Options:\n"); 823 fprintf(stderr, " -c Generate C-shell commands on stdout.\n"); 824 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n"); 825 fprintf(stderr, " -k Kill the current agent.\n"); 826 fprintf(stderr, " -d Debug mode.\n"); 827 exit(1); 828 } 829 830 int 831 main(int ac, char **av) 832 { 833 int sock, c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0, ch, nalloc; 834 struct sockaddr_un sunaddr; 835 struct rlimit rlim; 836 pid_t pid; 837 char *shell, *format, *pidstr, pidstrbuf[1 + 3 * sizeof pid]; 838 extern int optind; 839 fd_set *readsetp = NULL, *writesetp = NULL; 840 841 SSLeay_add_all_algorithms(); 842 843 while ((ch = getopt(ac, av, "cdks")) != -1) { 844 switch (ch) { 845 case 'c': 846 if (s_flag) 847 usage(); 848 c_flag++; 849 break; 850 case 'k': 851 k_flag++; 852 break; 853 case 's': 854 if (c_flag) 855 usage(); 856 s_flag++; 857 break; 858 case 'd': 859 if (d_flag) 860 usage(); 861 d_flag++; 862 break; 863 default: 864 usage(); 865 } 866 } 867 ac -= optind; 868 av += optind; 869 870 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag)) 871 usage(); 872 873 if (ac == 0 && !c_flag && !k_flag && !s_flag && !d_flag) { 874 shell = getenv("SHELL"); 875 if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0) 876 c_flag = 1; 877 } 878 if (k_flag) { 879 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 880 if (pidstr == NULL) { 881 fprintf(stderr, "%s not set, cannot kill agent\n", 882 SSH_AGENTPID_ENV_NAME); 883 exit(1); 884 } 885 pid = atoi(pidstr); 886 if (pid < 1) { 887 fprintf(stderr, "%s=\"%s\", which is not a good PID\n", 888 SSH_AGENTPID_ENV_NAME, pidstr); 889 exit(1); 890 } 891 if (kill(pid, SIGTERM) == -1) { 892 perror("kill"); 893 exit(1); 894 } 895 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 896 printf(format, SSH_AUTHSOCKET_ENV_NAME); 897 printf(format, SSH_AGENTPID_ENV_NAME); 898 printf("echo Agent pid %d killed;\n", pid); 899 exit(0); 900 } 901 parent_pid = getpid(); 902 903 /* Create private directory for agent socket */ 904 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXX", sizeof socket_dir); 905 if (mkdtemp(socket_dir) == NULL) { 906 perror("mkdtemp: private socket dir"); 907 exit(1); 908 } 909 snprintf(socket_name, sizeof socket_name, "%s/agent.%d", socket_dir, 910 parent_pid); 911 912 /* 913 * Create socket early so it will exist before command gets run from 914 * the parent. 915 */ 916 sock = socket(AF_UNIX, SOCK_STREAM, 0); 917 if (sock < 0) { 918 perror("socket"); 919 cleanup_exit(1); 920 } 921 memset(&sunaddr, 0, sizeof(sunaddr)); 922 sunaddr.sun_family = AF_UNIX; 923 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); 924 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) { 925 perror("bind"); 926 cleanup_exit(1); 927 } 928 if (listen(sock, 5) < 0) { 929 perror("listen"); 930 cleanup_exit(1); 931 } 932 933 /* 934 * Fork, and have the parent execute the command, if any, or present 935 * the socket data. The child continues as the authentication agent. 936 */ 937 if (d_flag) { 938 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1); 939 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 940 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 941 SSH_AUTHSOCKET_ENV_NAME); 942 printf("echo Agent pid %d;\n", parent_pid); 943 goto skip; 944 } 945 pid = fork(); 946 if (pid == -1) { 947 perror("fork"); 948 exit(1); 949 } 950 if (pid != 0) { /* Parent - execute the given command. */ 951 close(sock); 952 snprintf(pidstrbuf, sizeof pidstrbuf, "%d", pid); 953 if (ac == 0) { 954 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 955 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 956 SSH_AUTHSOCKET_ENV_NAME); 957 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 958 SSH_AGENTPID_ENV_NAME); 959 printf("echo Agent pid %d;\n", pid); 960 exit(0); 961 } 962 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 963 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 964 perror("setenv"); 965 exit(1); 966 } 967 execvp(av[0], av); 968 perror(av[0]); 969 exit(1); 970 } 971 972 if (setsid() == -1) { 973 perror("setsid"); 974 cleanup_exit(1); 975 } 976 977 (void)chdir("/"); 978 close(0); 979 close(1); 980 close(2); 981 982 /* deny core dumps, since memory contains unencrypted private keys */ 983 rlim.rlim_cur = rlim.rlim_max = 0; 984 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 985 perror("setrlimit rlimit_core failed"); 986 cleanup_exit(1); 987 } 988 989 skip: 990 if (atexit(cleanup_socket) < 0) { 991 perror("atexit"); 992 cleanup_exit(1); 993 } 994 new_socket(AUTH_SOCKET, sock); 995 if (ac > 0) { 996 signal(SIGALRM, check_parent_exists); 997 alarm(10); 998 } 999 idtab_init(); 1000 if (!d_flag) 1001 signal(SIGINT, SIG_IGN); 1002 signal(SIGPIPE, SIG_IGN); 1003 signal(SIGHUP, cleanup_handler); 1004 signal(SIGTERM, cleanup_handler); 1005 nalloc = 0; 1006 1007 while (1) { 1008 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc); 1009 if (select(max_fd + 1, readsetp, writesetp, NULL, NULL) < 0) { 1010 if (errno == EINTR) 1011 continue; 1012 exit(1); 1013 } 1014 after_select(readsetp, writesetp); 1015 } 1016 /* NOTREACHED */ 1017 } 1018