ssh-agent.c revision 98684
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> 38RCSID("$OpenBSD: ssh-agent.c,v 1.95 2002/06/19 00:27:55 deraadt Exp $"); 39RCSID("$FreeBSD: head/crypto/openssh/ssh-agent.c 98684 2002-06-23 16:09:08Z des $"); 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 "scard.h" 57#endif 58 59typedef enum { 60 AUTH_UNUSED, 61 AUTH_SOCKET, 62 AUTH_CONNECTION 63} sock_type; 64 65typedef struct { 66 int fd; 67 sock_type type; 68 Buffer input; 69 Buffer output; 70 Buffer request; 71} SocketEntry; 72 73u_int sockets_alloc = 0; 74SocketEntry *sockets = NULL; 75 76typedef struct identity { 77 TAILQ_ENTRY(identity) next; 78 Key *key; 79 char *comment; 80 u_int death; 81} Identity; 82 83typedef struct { 84 int nentries; 85 TAILQ_HEAD(idqueue, identity) idlist; 86} Idtab; 87 88/* private key table, one per protocol version */ 89Idtab idtable[3]; 90 91int max_fd = 0; 92 93/* pid of shell == parent of agent */ 94pid_t parent_pid = -1; 95 96/* pathname and directory for AUTH_SOCKET */ 97char socket_name[1024]; 98char socket_dir[1024]; 99 100/* locking */ 101int locked = 0; 102char *lock_passwd = NULL; 103 104extern char *__progname; 105 106static void 107idtab_init(void) 108{ 109 int i; 110 for (i = 0; i <=2; i++) { 111 TAILQ_INIT(&idtable[i].idlist); 112 idtable[i].nentries = 0; 113 } 114} 115 116/* return private key table for requested protocol version */ 117static Idtab * 118idtab_lookup(int version) 119{ 120 if (version < 1 || version > 2) 121 fatal("internal error, bad protocol version %d", version); 122 return &idtable[version]; 123} 124 125static void 126free_identity(Identity *id) 127{ 128 key_free(id->key); 129 xfree(id->comment); 130 xfree(id); 131} 132 133/* return matching private key for given public key */ 134static Identity * 135lookup_identity(Key *key, int version) 136{ 137 Identity *id; 138 139 Idtab *tab = idtab_lookup(version); 140 TAILQ_FOREACH(id, &tab->idlist, next) { 141 if (key_equal(key, id->key)) 142 return (id); 143 } 144 return (NULL); 145} 146 147/* send list of supported public keys to 'client' */ 148static void 149process_request_identities(SocketEntry *e, int version) 150{ 151 Idtab *tab = idtab_lookup(version); 152 Buffer msg; 153 Identity *id; 154 155 buffer_init(&msg); 156 buffer_put_char(&msg, (version == 1) ? 157 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 158 buffer_put_int(&msg, tab->nentries); 159 TAILQ_FOREACH(id, &tab->idlist, next) { 160 if (id->key->type == KEY_RSA1) { 161 buffer_put_int(&msg, BN_num_bits(id->key->rsa->n)); 162 buffer_put_bignum(&msg, id->key->rsa->e); 163 buffer_put_bignum(&msg, id->key->rsa->n); 164 } else { 165 u_char *blob; 166 u_int blen; 167 key_to_blob(id->key, &blob, &blen); 168 buffer_put_string(&msg, blob, blen); 169 xfree(blob); 170 } 171 buffer_put_cstring(&msg, id->comment); 172 } 173 buffer_put_int(&e->output, buffer_len(&msg)); 174 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 175 buffer_free(&msg); 176} 177 178/* ssh1 only */ 179static void 180process_authentication_challenge1(SocketEntry *e) 181{ 182 Identity *id; 183 Key *key; 184 BIGNUM *challenge; 185 int i, len; 186 Buffer msg; 187 MD5_CTX md; 188 u_char buf[32], mdbuf[16], session_id[16]; 189 u_int response_type; 190 191 buffer_init(&msg); 192 key = key_new(KEY_RSA1); 193 if ((challenge = BN_new()) == NULL) 194 fatal("process_authentication_challenge1: BN_new failed"); 195 196 buffer_get_int(&e->request); /* ignored */ 197 buffer_get_bignum(&e->request, key->rsa->e); 198 buffer_get_bignum(&e->request, key->rsa->n); 199 buffer_get_bignum(&e->request, challenge); 200 201 /* Only protocol 1.1 is supported */ 202 if (buffer_len(&e->request) == 0) 203 goto failure; 204 buffer_get(&e->request, session_id, 16); 205 response_type = buffer_get_int(&e->request); 206 if (response_type != 1) 207 goto failure; 208 209 id = lookup_identity(key, 1); 210 if (id != NULL) { 211 Key *private = id->key; 212 /* Decrypt the challenge using the private key. */ 213 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0) 214 goto failure; 215 216 /* The response is MD5 of decrypted challenge plus session id. */ 217 len = BN_num_bytes(challenge); 218 if (len <= 0 || len > 32) { 219 log("process_authentication_challenge: bad challenge length %d", len); 220 goto failure; 221 } 222 memset(buf, 0, 32); 223 BN_bn2bin(challenge, buf + 32 - len); 224 MD5_Init(&md); 225 MD5_Update(&md, buf, 32); 226 MD5_Update(&md, session_id, 16); 227 MD5_Final(mdbuf, &md); 228 229 /* Send the response. */ 230 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE); 231 for (i = 0; i < 16; i++) 232 buffer_put_char(&msg, mdbuf[i]); 233 goto send; 234 } 235 236failure: 237 /* Unknown identity or protocol error. Send failure. */ 238 buffer_put_char(&msg, SSH_AGENT_FAILURE); 239send: 240 buffer_put_int(&e->output, buffer_len(&msg)); 241 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 242 key_free(key); 243 BN_clear_free(challenge); 244 buffer_free(&msg); 245} 246 247/* ssh2 only */ 248static void 249process_sign_request2(SocketEntry *e) 250{ 251 extern int datafellows; 252 Key *key; 253 u_char *blob, *data, *signature = NULL; 254 u_int blen, dlen, slen = 0; 255 int flags; 256 Buffer msg; 257 int ok = -1; 258 259 datafellows = 0; 260 261 blob = buffer_get_string(&e->request, &blen); 262 data = buffer_get_string(&e->request, &dlen); 263 264 flags = buffer_get_int(&e->request); 265 if (flags & SSH_AGENT_OLD_SIGNATURE) 266 datafellows = SSH_BUG_SIGBLOB; 267 268 key = key_from_blob(blob, blen); 269 if (key != NULL) { 270 Identity *id = lookup_identity(key, 2); 271 if (id != NULL) 272 ok = key_sign(id->key, &signature, &slen, data, dlen); 273 } 274 key_free(key); 275 buffer_init(&msg); 276 if (ok == 0) { 277 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); 278 buffer_put_string(&msg, signature, slen); 279 } else { 280 buffer_put_char(&msg, SSH_AGENT_FAILURE); 281 } 282 buffer_put_int(&e->output, buffer_len(&msg)); 283 buffer_append(&e->output, buffer_ptr(&msg), 284 buffer_len(&msg)); 285 buffer_free(&msg); 286 xfree(data); 287 xfree(blob); 288 if (signature != NULL) 289 xfree(signature); 290} 291 292/* shared */ 293static void 294process_remove_identity(SocketEntry *e, int version) 295{ 296 Key *key = NULL; 297 u_char *blob; 298 u_int blen; 299 u_int bits; 300 int success = 0; 301 302 switch (version) { 303 case 1: 304 key = key_new(KEY_RSA1); 305 bits = buffer_get_int(&e->request); 306 buffer_get_bignum(&e->request, key->rsa->e); 307 buffer_get_bignum(&e->request, key->rsa->n); 308 309 if (bits != key_size(key)) 310 log("Warning: identity keysize mismatch: actual %d, announced %d", 311 key_size(key), bits); 312 break; 313 case 2: 314 blob = buffer_get_string(&e->request, &blen); 315 key = key_from_blob(blob, blen); 316 xfree(blob); 317 break; 318 } 319 if (key != NULL) { 320 Identity *id = lookup_identity(key, version); 321 if (id != NULL) { 322 /* 323 * We have this key. Free the old key. Since we 324 * don\'t want to leave empty slots in the middle of 325 * the array, we actually free the key there and move 326 * all the entries between the empty slot and the end 327 * of the array. 328 */ 329 Idtab *tab = idtab_lookup(version); 330 if (tab->nentries < 1) 331 fatal("process_remove_identity: " 332 "internal error: tab->nentries %d", 333 tab->nentries); 334 TAILQ_REMOVE(&tab->idlist, id, next); 335 free_identity(id); 336 tab->nentries--; 337 success = 1; 338 } 339 key_free(key); 340 } 341 buffer_put_int(&e->output, 1); 342 buffer_put_char(&e->output, 343 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 344} 345 346static void 347process_remove_all_identities(SocketEntry *e, int version) 348{ 349 Idtab *tab = idtab_lookup(version); 350 Identity *id; 351 352 /* Loop over all identities and clear the keys. */ 353 for (id = TAILQ_FIRST(&tab->idlist); id; 354 id = TAILQ_FIRST(&tab->idlist)) { 355 TAILQ_REMOVE(&tab->idlist, id, next); 356 free_identity(id); 357 } 358 359 /* Mark that there are no identities. */ 360 tab->nentries = 0; 361 362 /* Send success. */ 363 buffer_put_int(&e->output, 1); 364 buffer_put_char(&e->output, SSH_AGENT_SUCCESS); 365} 366 367static void 368reaper(void) 369{ 370 Idtab *tab; 371 Identity *id, *nxt; 372 int version; 373 u_int now = time(NULL); 374 375 for (version = 1; version < 3; version++) { 376 tab = idtab_lookup(version); 377 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 378 nxt = TAILQ_NEXT(id, next); 379 if (id->death != 0 && now >= id->death) { 380 TAILQ_REMOVE(&tab->idlist, id, next); 381 free_identity(id); 382 tab->nentries--; 383 } 384 } 385 } 386} 387 388static void 389process_add_identity(SocketEntry *e, int version) 390{ 391 Key *k = NULL; 392 char *type_name; 393 char *comment; 394 int type, success = 0, death = 0; 395 Idtab *tab = idtab_lookup(version); 396 397 switch (version) { 398 case 1: 399 k = key_new_private(KEY_RSA1); 400 buffer_get_int(&e->request); /* ignored */ 401 buffer_get_bignum(&e->request, k->rsa->n); 402 buffer_get_bignum(&e->request, k->rsa->e); 403 buffer_get_bignum(&e->request, k->rsa->d); 404 buffer_get_bignum(&e->request, k->rsa->iqmp); 405 406 /* SSH and SSL have p and q swapped */ 407 buffer_get_bignum(&e->request, k->rsa->q); /* p */ 408 buffer_get_bignum(&e->request, k->rsa->p); /* q */ 409 410 /* Generate additional parameters */ 411 rsa_generate_additional_parameters(k->rsa); 412 break; 413 case 2: 414 type_name = buffer_get_string(&e->request, NULL); 415 type = key_type_from_name(type_name); 416 xfree(type_name); 417 switch (type) { 418 case KEY_DSA: 419 k = key_new_private(type); 420 buffer_get_bignum2(&e->request, k->dsa->p); 421 buffer_get_bignum2(&e->request, k->dsa->q); 422 buffer_get_bignum2(&e->request, k->dsa->g); 423 buffer_get_bignum2(&e->request, k->dsa->pub_key); 424 buffer_get_bignum2(&e->request, k->dsa->priv_key); 425 break; 426 case KEY_RSA: 427 k = key_new_private(type); 428 buffer_get_bignum2(&e->request, k->rsa->n); 429 buffer_get_bignum2(&e->request, k->rsa->e); 430 buffer_get_bignum2(&e->request, k->rsa->d); 431 buffer_get_bignum2(&e->request, k->rsa->iqmp); 432 buffer_get_bignum2(&e->request, k->rsa->p); 433 buffer_get_bignum2(&e->request, k->rsa->q); 434 435 /* Generate additional parameters */ 436 rsa_generate_additional_parameters(k->rsa); 437 break; 438 default: 439 buffer_clear(&e->request); 440 goto send; 441 } 442 break; 443 } 444 comment = buffer_get_string(&e->request, NULL); 445 if (k == NULL) { 446 xfree(comment); 447 goto send; 448 } 449 success = 1; 450 while (buffer_len(&e->request)) { 451 switch (buffer_get_char(&e->request)) { 452 case SSH_AGENT_CONSTRAIN_LIFETIME: 453 death = time(NULL) + buffer_get_int(&e->request); 454 break; 455 default: 456 break; 457 } 458 } 459 if (lookup_identity(k, version) == NULL) { 460 Identity *id = xmalloc(sizeof(Identity)); 461 id->key = k; 462 id->comment = comment; 463 id->death = death; 464 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 465 /* Increment the number of identities. */ 466 tab->nentries++; 467 } else { 468 key_free(k); 469 xfree(comment); 470 } 471send: 472 buffer_put_int(&e->output, 1); 473 buffer_put_char(&e->output, 474 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 475} 476 477/* XXX todo: encrypt sensitive data with passphrase */ 478static void 479process_lock_agent(SocketEntry *e, int lock) 480{ 481 char *passwd; 482 int success = 0; 483 484 passwd = buffer_get_string(&e->request, NULL); 485 if (locked && !lock && strcmp(passwd, lock_passwd) == 0) { 486 locked = 0; 487 memset(lock_passwd, 0, strlen(lock_passwd)); 488 xfree(lock_passwd); 489 lock_passwd = NULL; 490 success = 1; 491 } else if (!locked && lock) { 492 locked = 1; 493 lock_passwd = xstrdup(passwd); 494 success = 1; 495 } 496 memset(passwd, 0, strlen(passwd)); 497 xfree(passwd); 498 499 buffer_put_int(&e->output, 1); 500 buffer_put_char(&e->output, 501 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 502} 503 504static void 505no_identities(SocketEntry *e, u_int type) 506{ 507 Buffer msg; 508 509 buffer_init(&msg); 510 buffer_put_char(&msg, 511 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ? 512 SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); 513 buffer_put_int(&msg, 0); 514 buffer_put_int(&e->output, buffer_len(&msg)); 515 buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); 516 buffer_free(&msg); 517} 518 519#ifdef SMARTCARD 520static void 521process_add_smartcard_key (SocketEntry *e) 522{ 523 Identity *id; 524 Idtab *tab; 525 Key **keys, *k; 526 char *sc_reader_id = NULL, *pin; 527 int i, version, success = 0; 528 529 sc_reader_id = buffer_get_string(&e->request, NULL); 530 pin = buffer_get_string(&e->request, NULL); 531 keys = sc_get_keys(sc_reader_id, pin); 532 xfree(sc_reader_id); 533 xfree(pin); 534 535 if (keys == NULL || keys[0] == NULL) { 536 error("sc_get_keys failed"); 537 goto send; 538 } 539 for (i = 0; keys[i] != NULL; i++) { 540 k = keys[i]; 541 version = k->type == KEY_RSA1 ? 1 : 2; 542 tab = idtab_lookup(version); 543 if (lookup_identity(k, version) == NULL) { 544 id = xmalloc(sizeof(Identity)); 545 id->key = k; 546 id->comment = xstrdup("smartcard key"); 547 id->death = 0; 548 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 549 tab->nentries++; 550 success = 1; 551 } else { 552 key_free(k); 553 } 554 keys[i] = NULL; 555 } 556 xfree(keys); 557send: 558 buffer_put_int(&e->output, 1); 559 buffer_put_char(&e->output, 560 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 561} 562 563static void 564process_remove_smartcard_key(SocketEntry *e) 565{ 566 Identity *id; 567 Idtab *tab; 568 Key **keys, *k = NULL; 569 char *sc_reader_id = NULL, *pin; 570 int i, version, success = 0; 571 572 sc_reader_id = buffer_get_string(&e->request, NULL); 573 pin = buffer_get_string(&e->request, NULL); 574 keys = sc_get_keys(sc_reader_id, pin); 575 xfree(sc_reader_id); 576 xfree(pin); 577 578 if (keys == NULL || keys[0] == NULL) { 579 error("sc_get_keys failed"); 580 goto send; 581 } 582 for (i = 0; keys[i] != NULL; i++) { 583 k = keys[i]; 584 version = k->type == KEY_RSA1 ? 1 : 2; 585 if ((id = lookup_identity(k, version)) != NULL) { 586 tab = idtab_lookup(version); 587 TAILQ_REMOVE(&tab->idlist, id, next); 588 tab->nentries--; 589 free_identity(id); 590 success = 1; 591 } 592 key_free(k); 593 keys[i] = NULL; 594 } 595 xfree(keys); 596send: 597 buffer_put_int(&e->output, 1); 598 buffer_put_char(&e->output, 599 success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); 600} 601#endif /* SMARTCARD */ 602 603/* dispatch incoming messages */ 604 605static void 606process_message(SocketEntry *e) 607{ 608 u_int msg_len; 609 u_int type; 610 u_char *cp; 611 612 /* kill dead keys */ 613 reaper(); 614 615 if (buffer_len(&e->input) < 5) 616 return; /* Incomplete message. */ 617 cp = buffer_ptr(&e->input); 618 msg_len = GET_32BIT(cp); 619 if (msg_len > 256 * 1024) { 620 shutdown(e->fd, SHUT_RDWR); 621 close(e->fd); 622 e->type = AUTH_UNUSED; 623 buffer_free(&e->input); 624 buffer_free(&e->output); 625 buffer_free(&e->request); 626 return; 627 } 628 if (buffer_len(&e->input) < msg_len + 4) 629 return; 630 631 /* move the current input to e->request */ 632 buffer_consume(&e->input, 4); 633 buffer_clear(&e->request); 634 buffer_append(&e->request, buffer_ptr(&e->input), msg_len); 635 buffer_consume(&e->input, msg_len); 636 type = buffer_get_char(&e->request); 637 638 /* check wheter agent is locked */ 639 if (locked && type != SSH_AGENTC_UNLOCK) { 640 buffer_clear(&e->request); 641 switch (type) { 642 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 643 case SSH2_AGENTC_REQUEST_IDENTITIES: 644 /* send empty lists */ 645 no_identities(e, type); 646 break; 647 default: 648 /* send a fail message for all other request types */ 649 buffer_put_int(&e->output, 1); 650 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 651 } 652 return; 653 } 654 655 debug("type %d", type); 656 switch (type) { 657 case SSH_AGENTC_LOCK: 658 case SSH_AGENTC_UNLOCK: 659 process_lock_agent(e, type == SSH_AGENTC_LOCK); 660 break; 661 /* ssh1 */ 662 case SSH_AGENTC_RSA_CHALLENGE: 663 process_authentication_challenge1(e); 664 break; 665 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 666 process_request_identities(e, 1); 667 break; 668 case SSH_AGENTC_ADD_RSA_IDENTITY: 669 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 670 process_add_identity(e, 1); 671 break; 672 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 673 process_remove_identity(e, 1); 674 break; 675 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 676 process_remove_all_identities(e, 1); 677 break; 678 /* ssh2 */ 679 case SSH2_AGENTC_SIGN_REQUEST: 680 process_sign_request2(e); 681 break; 682 case SSH2_AGENTC_REQUEST_IDENTITIES: 683 process_request_identities(e, 2); 684 break; 685 case SSH2_AGENTC_ADD_IDENTITY: 686 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 687 process_add_identity(e, 2); 688 break; 689 case SSH2_AGENTC_REMOVE_IDENTITY: 690 process_remove_identity(e, 2); 691 break; 692 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 693 process_remove_all_identities(e, 2); 694 break; 695#ifdef SMARTCARD 696 case SSH_AGENTC_ADD_SMARTCARD_KEY: 697 process_add_smartcard_key(e); 698 break; 699 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 700 process_remove_smartcard_key(e); 701 break; 702#endif /* SMARTCARD */ 703 default: 704 /* Unknown message. Respond with failure. */ 705 error("Unknown message %d", type); 706 buffer_clear(&e->request); 707 buffer_put_int(&e->output, 1); 708 buffer_put_char(&e->output, SSH_AGENT_FAILURE); 709 break; 710 } 711} 712 713static void 714new_socket(sock_type type, int fd) 715{ 716 u_int i, old_alloc; 717 if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) 718 error("fcntl O_NONBLOCK: %s", strerror(errno)); 719 720 if (fd > max_fd) 721 max_fd = fd; 722 723 for (i = 0; i < sockets_alloc; i++) 724 if (sockets[i].type == AUTH_UNUSED) { 725 sockets[i].fd = fd; 726 sockets[i].type = type; 727 buffer_init(&sockets[i].input); 728 buffer_init(&sockets[i].output); 729 buffer_init(&sockets[i].request); 730 return; 731 } 732 old_alloc = sockets_alloc; 733 sockets_alloc += 10; 734 if (sockets) 735 sockets = xrealloc(sockets, sockets_alloc * sizeof(sockets[0])); 736 else 737 sockets = xmalloc(sockets_alloc * sizeof(sockets[0])); 738 for (i = old_alloc; i < sockets_alloc; i++) 739 sockets[i].type = AUTH_UNUSED; 740 sockets[old_alloc].type = type; 741 sockets[old_alloc].fd = fd; 742 buffer_init(&sockets[old_alloc].input); 743 buffer_init(&sockets[old_alloc].output); 744 buffer_init(&sockets[old_alloc].request); 745} 746 747static int 748prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, int *nallocp) 749{ 750 u_int i, sz; 751 int n = 0; 752 753 for (i = 0; i < sockets_alloc; i++) { 754 switch (sockets[i].type) { 755 case AUTH_SOCKET: 756 case AUTH_CONNECTION: 757 n = MAX(n, sockets[i].fd); 758 break; 759 case AUTH_UNUSED: 760 break; 761 default: 762 fatal("Unknown socket type %d", sockets[i].type); 763 break; 764 } 765 } 766 767 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 768 if (*fdrp == NULL || sz > *nallocp) { 769 if (*fdrp) 770 xfree(*fdrp); 771 if (*fdwp) 772 xfree(*fdwp); 773 *fdrp = xmalloc(sz); 774 *fdwp = xmalloc(sz); 775 *nallocp = sz; 776 } 777 if (n < *fdl) 778 debug("XXX shrink: %d < %d", n, *fdl); 779 *fdl = n; 780 memset(*fdrp, 0, sz); 781 memset(*fdwp, 0, sz); 782 783 for (i = 0; i < sockets_alloc; i++) { 784 switch (sockets[i].type) { 785 case AUTH_SOCKET: 786 case AUTH_CONNECTION: 787 FD_SET(sockets[i].fd, *fdrp); 788 if (buffer_len(&sockets[i].output) > 0) 789 FD_SET(sockets[i].fd, *fdwp); 790 break; 791 default: 792 break; 793 } 794 } 795 return (1); 796} 797 798static void 799after_select(fd_set *readset, fd_set *writeset) 800{ 801 u_int i; 802 int len, sock; 803 socklen_t slen; 804 char buf[1024]; 805 struct sockaddr_un sunaddr; 806 807 for (i = 0; i < sockets_alloc; i++) 808 switch (sockets[i].type) { 809 case AUTH_UNUSED: 810 break; 811 case AUTH_SOCKET: 812 if (FD_ISSET(sockets[i].fd, readset)) { 813 slen = sizeof(sunaddr); 814 sock = accept(sockets[i].fd, 815 (struct sockaddr *) &sunaddr, &slen); 816 if (sock < 0) { 817 error("accept from AUTH_SOCKET: %s", 818 strerror(errno)); 819 break; 820 } 821 new_socket(AUTH_CONNECTION, sock); 822 } 823 break; 824 case AUTH_CONNECTION: 825 if (buffer_len(&sockets[i].output) > 0 && 826 FD_ISSET(sockets[i].fd, writeset)) { 827 do { 828 len = write(sockets[i].fd, 829 buffer_ptr(&sockets[i].output), 830 buffer_len(&sockets[i].output)); 831 if (len == -1 && (errno == EAGAIN || 832 errno == EINTR)) 833 continue; 834 break; 835 } while (1); 836 if (len <= 0) { 837 shutdown(sockets[i].fd, SHUT_RDWR); 838 close(sockets[i].fd); 839 sockets[i].type = AUTH_UNUSED; 840 buffer_free(&sockets[i].input); 841 buffer_free(&sockets[i].output); 842 buffer_free(&sockets[i].request); 843 break; 844 } 845 buffer_consume(&sockets[i].output, len); 846 } 847 if (FD_ISSET(sockets[i].fd, readset)) { 848 do { 849 len = read(sockets[i].fd, buf, sizeof(buf)); 850 if (len == -1 && (errno == EAGAIN || 851 errno == EINTR)) 852 continue; 853 break; 854 } while (1); 855 if (len <= 0) { 856 shutdown(sockets[i].fd, SHUT_RDWR); 857 close(sockets[i].fd); 858 sockets[i].type = AUTH_UNUSED; 859 buffer_free(&sockets[i].input); 860 buffer_free(&sockets[i].output); 861 buffer_free(&sockets[i].request); 862 break; 863 } 864 buffer_append(&sockets[i].input, buf, len); 865 process_message(&sockets[i]); 866 } 867 break; 868 default: 869 fatal("Unknown type %d", sockets[i].type); 870 } 871} 872 873static void 874cleanup_socket(void *p) 875{ 876 if (socket_name[0]) 877 unlink(socket_name); 878 if (socket_dir[0]) 879 rmdir(socket_dir); 880} 881 882static void 883cleanup_exit(int i) 884{ 885 cleanup_socket(NULL); 886 exit(i); 887} 888 889static void 890cleanup_handler(int sig) 891{ 892 cleanup_socket(NULL); 893 _exit(2); 894} 895 896static void 897check_parent_exists(int sig) 898{ 899 int save_errno = errno; 900 901 if (parent_pid != -1 && kill(parent_pid, 0) < 0) { 902 /* printf("Parent has died - Authentication agent exiting.\n"); */ 903 cleanup_handler(sig); /* safe */ 904 } 905 signal(SIGALRM, check_parent_exists); 906 alarm(10); 907 errno = save_errno; 908} 909 910static void 911usage(void) 912{ 913 fprintf(stderr, "Usage: %s [options] [command [args ...]]\n", 914 __progname); 915 fprintf(stderr, "Options:\n"); 916 fprintf(stderr, " -c Generate C-shell commands on stdout.\n"); 917 fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n"); 918 fprintf(stderr, " -k Kill the current agent.\n"); 919 fprintf(stderr, " -d Debug mode.\n"); 920 fprintf(stderr, " -a socket Bind agent socket to given name.\n"); 921 exit(1); 922} 923 924int 925main(int ac, char **av) 926{ 927 int sock, c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0, ch, nalloc; 928 struct sockaddr_un sunaddr; 929 struct rlimit rlim; 930 pid_t pid; 931 char *shell, *format, *pidstr, pidstrbuf[1 + 3 * sizeof pid]; 932 char *agentsocket = NULL; 933 extern int optind; 934 fd_set *readsetp = NULL, *writesetp = NULL; 935 936 SSLeay_add_all_algorithms(); 937 938 while ((ch = getopt(ac, av, "cdksa:")) != -1) { 939 switch (ch) { 940 case 'c': 941 if (s_flag) 942 usage(); 943 c_flag++; 944 break; 945 case 'k': 946 k_flag++; 947 break; 948 case 's': 949 if (c_flag) 950 usage(); 951 s_flag++; 952 break; 953 case 'd': 954 if (d_flag) 955 usage(); 956 d_flag++; 957 break; 958 case 'a': 959 agentsocket = optarg; 960 break; 961 default: 962 usage(); 963 } 964 } 965 ac -= optind; 966 av += optind; 967 968 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag)) 969 usage(); 970 971 if (ac == 0 && !c_flag && !s_flag) { 972 shell = getenv("SHELL"); 973 if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0) 974 c_flag = 1; 975 } 976 if (k_flag) { 977 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 978 if (pidstr == NULL) { 979 fprintf(stderr, "%s not set, cannot kill agent\n", 980 SSH_AGENTPID_ENV_NAME); 981 exit(1); 982 } 983 pid = atoi(pidstr); 984 if (pid < 1) { 985 fprintf(stderr, "%s=\"%s\", which is not a good PID\n", 986 SSH_AGENTPID_ENV_NAME, pidstr); 987 exit(1); 988 } 989 if (kill(pid, SIGTERM) == -1) { 990 perror("kill"); 991 exit(1); 992 } 993 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 994 printf(format, SSH_AUTHSOCKET_ENV_NAME); 995 printf(format, SSH_AGENTPID_ENV_NAME); 996 printf("echo Agent pid %ld killed;\n", (long)pid); 997 exit(0); 998 } 999 parent_pid = getpid(); 1000 1001 if (agentsocket == NULL) { 1002 /* Create private directory for agent socket */ 1003 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXX", sizeof socket_dir); 1004 if (mkdtemp(socket_dir) == NULL) { 1005 perror("mkdtemp: private socket dir"); 1006 exit(1); 1007 } 1008 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1009 (long)parent_pid); 1010 } else { 1011 /* Try to use specified agent socket */ 1012 socket_dir[0] = '\0'; 1013 strlcpy(socket_name, agentsocket, sizeof socket_name); 1014 } 1015 1016 /* 1017 * Create socket early so it will exist before command gets run from 1018 * the parent. 1019 */ 1020 sock = socket(AF_UNIX, SOCK_STREAM, 0); 1021 if (sock < 0) { 1022 perror("socket"); 1023 cleanup_exit(1); 1024 } 1025 memset(&sunaddr, 0, sizeof(sunaddr)); 1026 sunaddr.sun_family = AF_UNIX; 1027 strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); 1028 sunaddr.sun_len = SUN_LEN(&sunaddr) + 1; 1029 if (bind(sock, (struct sockaddr *)&sunaddr, sunaddr.sun_len) < 0) { 1030 perror("bind"); 1031 cleanup_exit(1); 1032 } 1033 if (listen(sock, 5) < 0) { 1034 perror("listen"); 1035 cleanup_exit(1); 1036 } 1037 1038 /* 1039 * Fork, and have the parent execute the command, if any, or present 1040 * the socket data. The child continues as the authentication agent. 1041 */ 1042 if (d_flag) { 1043 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1); 1044 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1045 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1046 SSH_AUTHSOCKET_ENV_NAME); 1047 printf("echo Agent pid %ld;\n", (long)parent_pid); 1048 goto skip; 1049 } 1050 pid = fork(); 1051 if (pid == -1) { 1052 perror("fork"); 1053 cleanup_exit(1); 1054 } 1055 if (pid != 0) { /* Parent - execute the given command. */ 1056 close(sock); 1057 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1058 if (ac == 0) { 1059 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1060 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1061 SSH_AUTHSOCKET_ENV_NAME); 1062 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 1063 SSH_AGENTPID_ENV_NAME); 1064 printf("echo Agent pid %ld;\n", (long)pid); 1065 exit(0); 1066 } 1067 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1068 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1069 perror("setenv"); 1070 exit(1); 1071 } 1072 execvp(av[0], av); 1073 perror(av[0]); 1074 exit(1); 1075 } 1076 /* child */ 1077 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1078 1079 if (setsid() == -1) { 1080 error("setsid: %s", strerror(errno)); 1081 cleanup_exit(1); 1082 } 1083 1084 (void)chdir("/"); 1085 close(0); 1086 close(1); 1087 close(2); 1088 1089 /* deny core dumps, since memory contains unencrypted private keys */ 1090 rlim.rlim_cur = rlim.rlim_max = 0; 1091 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 1092 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1093 cleanup_exit(1); 1094 } 1095 1096skip: 1097 fatal_add_cleanup(cleanup_socket, NULL); 1098 new_socket(AUTH_SOCKET, sock); 1099 if (ac > 0) { 1100 signal(SIGALRM, check_parent_exists); 1101 alarm(10); 1102 } 1103 idtab_init(); 1104 if (!d_flag) 1105 signal(SIGINT, SIG_IGN); 1106 signal(SIGPIPE, SIG_IGN); 1107 signal(SIGHUP, cleanup_handler); 1108 signal(SIGTERM, cleanup_handler); 1109 nalloc = 0; 1110 1111 while (1) { 1112 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc); 1113 if (select(max_fd + 1, readsetp, writesetp, NULL, NULL) < 0) { 1114 if (errno == EINTR) 1115 continue; 1116 fatal("select: %s", strerror(errno)); 1117 } 1118 after_select(readsetp, writesetp); 1119 } 1120 /* NOTREACHED */ 1121} 1122