1 /* $OpenBSD: ssh-agent.c,v 1.203 2015/05/15 05:44:21 dtucker Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * The authentication agent program. 7 * 8 * As far as I am concerned, the code I have written for this software 9 * can be used freely for any purpose. Any derived versions of this 10 * software must be clearly marked as such, and if the derived work is 11 * incompatible with the protocol description in the RFC file, it must be 12 * called by a name other than "ssh" or "Secure Shell". 13 * 14 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 15 * 16 * Redistribution and use in source and binary forms, with or without 17 * modification, are permitted provided that the following conditions 18 * are met: 19 * 1. Redistributions of source code must retain the above copyright 20 * notice, this list of conditions and the following disclaimer. 21 * 2. Redistributions in binary form must reproduce the above copyright 22 * notice, this list of conditions and the following disclaimer in the 23 * documentation and/or other materials provided with the distribution. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 26 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 27 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 28 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 29 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 30 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 31 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 34 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 35 */ 36 37 #include "includes.h" 38 __RCSID("$FreeBSD$"); 39 40 #include <sys/param.h> /* MIN MAX */ 41 #include <sys/types.h> 42 #include <sys/param.h> 43 #include <sys/resource.h> 44 #include <sys/stat.h> 45 #include <sys/socket.h> 46 #ifdef HAVE_SYS_TIME_H 47 # include <sys/time.h> 48 #endif 49 #ifdef HAVE_SYS_UN_H 50 # include <sys/un.h> 51 #endif 52 #include "openbsd-compat/sys-queue.h" 53 54 #ifdef WITH_OPENSSL 55 #include <openssl/evp.h> 56 #include "openbsd-compat/openssl-compat.h" 57 #endif 58 59 #include <errno.h> 60 #include <fcntl.h> 61 #include <limits.h> 62 #ifdef HAVE_PATHS_H 63 # include <paths.h> 64 #endif 65 #include <signal.h> 66 #include <stdarg.h> 67 #include <stdio.h> 68 #include <stdlib.h> 69 #include <time.h> 70 #include <string.h> 71 #include <unistd.h> 72 #ifdef HAVE_UTIL_H 73 # include <util.h> 74 #endif 75 76 #include "key.h" /* XXX for typedef */ 77 #include "buffer.h" /* XXX for typedef */ 78 79 #include "xmalloc.h" 80 #include "ssh.h" 81 #include "rsa.h" 82 #include "sshbuf.h" 83 #include "sshkey.h" 84 #include "authfd.h" 85 #include "compat.h" 86 #include "log.h" 87 #include "misc.h" 88 #include "digest.h" 89 #include "ssherr.h" 90 91 #ifdef ENABLE_PKCS11 92 #include "ssh-pkcs11.h" 93 #endif 94 95 #if defined(HAVE_SYS_PRCTL_H) 96 #include <sys/prctl.h> /* For prctl() and PR_SET_DUMPABLE */ 97 #endif 98 99 typedef enum { 100 AUTH_UNUSED, 101 AUTH_SOCKET, 102 AUTH_CONNECTION 103 } sock_type; 104 105 typedef struct { 106 int fd; 107 sock_type type; 108 struct sshbuf *input; 109 struct sshbuf *output; 110 struct sshbuf *request; 111 } SocketEntry; 112 113 u_int sockets_alloc = 0; 114 SocketEntry *sockets = NULL; 115 116 typedef struct identity { 117 TAILQ_ENTRY(identity) next; 118 struct sshkey *key; 119 char *comment; 120 char *provider; 121 time_t death; 122 u_int confirm; 123 } Identity; 124 125 typedef struct { 126 int nentries; 127 TAILQ_HEAD(idqueue, identity) idlist; 128 } Idtab; 129 130 /* private key table, one per protocol version */ 131 Idtab idtable[3]; 132 133 int max_fd = 0; 134 135 /* pid of shell == parent of agent */ 136 pid_t parent_pid = -1; 137 time_t parent_alive_interval = 0; 138 139 /* pid of process for which cleanup_socket is applicable */ 140 pid_t cleanup_pid = 0; 141 142 /* pathname and directory for AUTH_SOCKET */ 143 char socket_name[PATH_MAX]; 144 char socket_dir[PATH_MAX]; 145 146 /* locking */ 147 #define LOCK_SIZE 32 148 #define LOCK_SALT_SIZE 16 149 #define LOCK_ROUNDS 1 150 int locked = 0; 151 char lock_passwd[LOCK_SIZE]; 152 char lock_salt[LOCK_SALT_SIZE]; 153 154 extern char *__progname; 155 156 /* Default lifetime in seconds (0 == forever) */ 157 static long lifetime = 0; 158 159 static int fingerprint_hash = SSH_FP_HASH_DEFAULT; 160 161 /* 162 * Client connection count; incremented in new_socket() and decremented in 163 * close_socket(). When it reaches 0, ssh-agent will exit. Since it is 164 * normally initialized to 1, it will never reach 0. However, if the -x 165 * option is specified, it is initialized to 0 in main(); in that case, 166 * ssh-agent will exit as soon as it has had at least one client but no 167 * longer has any. 168 */ 169 static int xcount = 1; 170 171 static void 172 close_socket(SocketEntry *e) 173 { 174 int last = 0; 175 176 if (e->type == AUTH_CONNECTION) { 177 debug("xcount %d -> %d", xcount, xcount - 1); 178 if (--xcount == 0) 179 last = 1; 180 } 181 close(e->fd); 182 e->fd = -1; 183 e->type = AUTH_UNUSED; 184 sshbuf_free(e->input); 185 sshbuf_free(e->output); 186 sshbuf_free(e->request); 187 if (last) 188 cleanup_exit(0); 189 } 190 191 static void 192 idtab_init(void) 193 { 194 int i; 195 196 for (i = 0; i <=2; i++) { 197 TAILQ_INIT(&idtable[i].idlist); 198 idtable[i].nentries = 0; 199 } 200 } 201 202 /* return private key table for requested protocol version */ 203 static Idtab * 204 idtab_lookup(int version) 205 { 206 if (version < 1 || version > 2) 207 fatal("internal error, bad protocol version %d", version); 208 return &idtable[version]; 209 } 210 211 static void 212 free_identity(Identity *id) 213 { 214 sshkey_free(id->key); 215 free(id->provider); 216 free(id->comment); 217 free(id); 218 } 219 220 /* return matching private key for given public key */ 221 static Identity * 222 lookup_identity(struct sshkey *key, int version) 223 { 224 Identity *id; 225 226 Idtab *tab = idtab_lookup(version); 227 TAILQ_FOREACH(id, &tab->idlist, next) { 228 if (sshkey_equal(key, id->key)) 229 return (id); 230 } 231 return (NULL); 232 } 233 234 /* Check confirmation of keysign request */ 235 static int 236 confirm_key(Identity *id) 237 { 238 char *p; 239 int ret = -1; 240 241 p = sshkey_fingerprint(id->key, fingerprint_hash, SSH_FP_DEFAULT); 242 if (p != NULL && 243 ask_permission("Allow use of key %s?\nKey fingerprint %s.", 244 id->comment, p)) 245 ret = 0; 246 free(p); 247 248 return (ret); 249 } 250 251 static void 252 send_status(SocketEntry *e, int success) 253 { 254 int r; 255 256 if ((r = sshbuf_put_u32(e->output, 1)) != 0 || 257 (r = sshbuf_put_u8(e->output, success ? 258 SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0) 259 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 260 } 261 262 /* send list of supported public keys to 'client' */ 263 static void 264 process_request_identities(SocketEntry *e, int version) 265 { 266 Idtab *tab = idtab_lookup(version); 267 Identity *id; 268 struct sshbuf *msg; 269 int r; 270 271 if ((msg = sshbuf_new()) == NULL) 272 fatal("%s: sshbuf_new failed", __func__); 273 if ((r = sshbuf_put_u8(msg, (version == 1) ? 274 SSH_AGENT_RSA_IDENTITIES_ANSWER : 275 SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 276 (r = sshbuf_put_u32(msg, tab->nentries)) != 0) 277 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 278 TAILQ_FOREACH(id, &tab->idlist, next) { 279 if (id->key->type == KEY_RSA1) { 280 #ifdef WITH_SSH1 281 if ((r = sshbuf_put_u32(msg, 282 BN_num_bits(id->key->rsa->n))) != 0 || 283 (r = sshbuf_put_bignum1(msg, 284 id->key->rsa->e)) != 0 || 285 (r = sshbuf_put_bignum1(msg, 286 id->key->rsa->n)) != 0) 287 fatal("%s: buffer error: %s", 288 __func__, ssh_err(r)); 289 #endif 290 } else { 291 u_char *blob; 292 size_t blen; 293 294 if ((r = sshkey_to_blob(id->key, &blob, &blen)) != 0) { 295 error("%s: sshkey_to_blob: %s", __func__, 296 ssh_err(r)); 297 continue; 298 } 299 if ((r = sshbuf_put_string(msg, blob, blen)) != 0) 300 fatal("%s: buffer error: %s", 301 __func__, ssh_err(r)); 302 free(blob); 303 } 304 if ((r = sshbuf_put_cstring(msg, id->comment)) != 0) 305 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 306 } 307 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 308 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 309 sshbuf_free(msg); 310 } 311 312 #ifdef WITH_SSH1 313 /* ssh1 only */ 314 static void 315 process_authentication_challenge1(SocketEntry *e) 316 { 317 u_char buf[32], mdbuf[16], session_id[16]; 318 u_int response_type; 319 BIGNUM *challenge; 320 Identity *id; 321 int r, len; 322 struct sshbuf *msg; 323 struct ssh_digest_ctx *md; 324 struct sshkey *key; 325 326 if ((msg = sshbuf_new()) == NULL) 327 fatal("%s: sshbuf_new failed", __func__); 328 if ((key = sshkey_new(KEY_RSA1)) == NULL) 329 fatal("%s: sshkey_new failed", __func__); 330 if ((challenge = BN_new()) == NULL) 331 fatal("%s: BN_new failed", __func__); 332 333 if ((r = sshbuf_get_u32(e->request, NULL)) != 0 || /* ignored */ 334 (r = sshbuf_get_bignum1(e->request, key->rsa->e)) != 0 || 335 (r = sshbuf_get_bignum1(e->request, key->rsa->n)) != 0 || 336 (r = sshbuf_get_bignum1(e->request, challenge))) 337 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 338 339 /* Only protocol 1.1 is supported */ 340 if (sshbuf_len(e->request) == 0) 341 goto failure; 342 if ((r = sshbuf_get(e->request, session_id, sizeof(session_id))) != 0 || 343 (r = sshbuf_get_u32(e->request, &response_type)) != 0) 344 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 345 if (response_type != 1) 346 goto failure; 347 348 id = lookup_identity(key, 1); 349 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) { 350 struct sshkey *private = id->key; 351 /* Decrypt the challenge using the private key. */ 352 if ((r = rsa_private_decrypt(challenge, challenge, 353 private->rsa) != 0)) { 354 fatal("%s: rsa_public_encrypt: %s", __func__, 355 ssh_err(r)); 356 goto failure; /* XXX ? */ 357 } 358 359 /* The response is MD5 of decrypted challenge plus session id */ 360 len = BN_num_bytes(challenge); 361 if (len <= 0 || len > 32) { 362 logit("%s: bad challenge length %d", __func__, len); 363 goto failure; 364 } 365 memset(buf, 0, 32); 366 BN_bn2bin(challenge, buf + 32 - len); 367 if ((md = ssh_digest_start(SSH_DIGEST_MD5)) == NULL || 368 ssh_digest_update(md, buf, 32) < 0 || 369 ssh_digest_update(md, session_id, 16) < 0 || 370 ssh_digest_final(md, mdbuf, sizeof(mdbuf)) < 0) 371 fatal("%s: md5 failed", __func__); 372 ssh_digest_free(md); 373 374 /* Send the response. */ 375 if ((r = sshbuf_put_u8(msg, SSH_AGENT_RSA_RESPONSE)) != 0 || 376 (r = sshbuf_put(msg, mdbuf, sizeof(mdbuf))) != 0) 377 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 378 goto send; 379 } 380 381 failure: 382 /* Unknown identity or protocol error. Send failure. */ 383 if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0) 384 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 385 send: 386 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 387 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 388 sshkey_free(key); 389 BN_clear_free(challenge); 390 sshbuf_free(msg); 391 } 392 #endif 393 394 /* ssh2 only */ 395 static void 396 process_sign_request2(SocketEntry *e) 397 { 398 u_char *blob, *data, *signature = NULL; 399 size_t blen, dlen, slen = 0; 400 u_int compat = 0, flags; 401 int r, ok = -1; 402 struct sshbuf *msg; 403 struct sshkey *key; 404 struct identity *id; 405 406 if ((msg = sshbuf_new()) == NULL) 407 fatal("%s: sshbuf_new failed", __func__); 408 if ((r = sshbuf_get_string(e->request, &blob, &blen)) != 0 || 409 (r = sshbuf_get_string(e->request, &data, &dlen)) != 0 || 410 (r = sshbuf_get_u32(e->request, &flags)) != 0) 411 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 412 if (flags & SSH_AGENT_OLD_SIGNATURE) 413 compat = SSH_BUG_SIGBLOB; 414 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) { 415 error("%s: cannot parse key blob: %s", __func__, ssh_err(ok)); 416 goto send; 417 } 418 if ((id = lookup_identity(key, 2)) == NULL) { 419 verbose("%s: %s key not found", __func__, sshkey_type(key)); 420 goto send; 421 } 422 if (id->confirm && confirm_key(id) != 0) { 423 verbose("%s: user refused key", __func__); 424 goto send; 425 } 426 if ((r = sshkey_sign(id->key, &signature, &slen, 427 data, dlen, compat)) != 0) { 428 error("%s: sshkey_sign: %s", __func__, ssh_err(ok)); 429 goto send; 430 } 431 /* Success */ 432 ok = 0; 433 send: 434 sshkey_free(key); 435 if (ok == 0) { 436 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 || 437 (r = sshbuf_put_string(msg, signature, slen)) != 0) 438 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 439 } else if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0) 440 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 441 442 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 443 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 444 445 sshbuf_free(msg); 446 free(data); 447 free(blob); 448 free(signature); 449 } 450 451 /* shared */ 452 static void 453 process_remove_identity(SocketEntry *e, int version) 454 { 455 size_t blen; 456 int r, success = 0; 457 struct sshkey *key = NULL; 458 u_char *blob; 459 #ifdef WITH_SSH1 460 u_int bits; 461 #endif /* WITH_SSH1 */ 462 463 switch (version) { 464 #ifdef WITH_SSH1 465 case 1: 466 if ((key = sshkey_new(KEY_RSA1)) == NULL) { 467 error("%s: sshkey_new failed", __func__); 468 return; 469 } 470 if ((r = sshbuf_get_u32(e->request, &bits)) != 0 || 471 (r = sshbuf_get_bignum1(e->request, key->rsa->e)) != 0 || 472 (r = sshbuf_get_bignum1(e->request, key->rsa->n)) != 0) 473 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 474 475 if (bits != sshkey_size(key)) 476 logit("Warning: identity keysize mismatch: " 477 "actual %u, announced %u", 478 sshkey_size(key), bits); 479 break; 480 #endif /* WITH_SSH1 */ 481 case 2: 482 if ((r = sshbuf_get_string(e->request, &blob, &blen)) != 0) 483 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 484 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) 485 error("%s: sshkey_from_blob failed: %s", 486 __func__, ssh_err(r)); 487 free(blob); 488 break; 489 } 490 if (key != NULL) { 491 Identity *id = lookup_identity(key, version); 492 if (id != NULL) { 493 /* 494 * We have this key. Free the old key. Since we 495 * don't want to leave empty slots in the middle of 496 * the array, we actually free the key there and move 497 * all the entries between the empty slot and the end 498 * of the array. 499 */ 500 Idtab *tab = idtab_lookup(version); 501 if (tab->nentries < 1) 502 fatal("process_remove_identity: " 503 "internal error: tab->nentries %d", 504 tab->nentries); 505 TAILQ_REMOVE(&tab->idlist, id, next); 506 free_identity(id); 507 tab->nentries--; 508 success = 1; 509 } 510 sshkey_free(key); 511 } 512 send_status(e, success); 513 } 514 515 static void 516 process_remove_all_identities(SocketEntry *e, int version) 517 { 518 Idtab *tab = idtab_lookup(version); 519 Identity *id; 520 521 /* Loop over all identities and clear the keys. */ 522 for (id = TAILQ_FIRST(&tab->idlist); id; 523 id = TAILQ_FIRST(&tab->idlist)) { 524 TAILQ_REMOVE(&tab->idlist, id, next); 525 free_identity(id); 526 } 527 528 /* Mark that there are no identities. */ 529 tab->nentries = 0; 530 531 /* Send success. */ 532 send_status(e, 1); 533 } 534 535 /* removes expired keys and returns number of seconds until the next expiry */ 536 static time_t 537 reaper(void) 538 { 539 time_t deadline = 0, now = monotime(); 540 Identity *id, *nxt; 541 int version; 542 Idtab *tab; 543 544 for (version = 1; version < 3; version++) { 545 tab = idtab_lookup(version); 546 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 547 nxt = TAILQ_NEXT(id, next); 548 if (id->death == 0) 549 continue; 550 if (now >= id->death) { 551 debug("expiring key '%s'", id->comment); 552 TAILQ_REMOVE(&tab->idlist, id, next); 553 free_identity(id); 554 tab->nentries--; 555 } else 556 deadline = (deadline == 0) ? id->death : 557 MIN(deadline, id->death); 558 } 559 } 560 if (deadline == 0 || deadline <= now) 561 return 0; 562 else 563 return (deadline - now); 564 } 565 566 /* 567 * XXX this and the corresponding serialisation function probably belongs 568 * in key.c 569 */ 570 #ifdef WITH_SSH1 571 static int 572 agent_decode_rsa1(struct sshbuf *m, struct sshkey **kp) 573 { 574 struct sshkey *k = NULL; 575 int r = SSH_ERR_INTERNAL_ERROR; 576 577 *kp = NULL; 578 if ((k = sshkey_new_private(KEY_RSA1)) == NULL) 579 return SSH_ERR_ALLOC_FAIL; 580 581 if ((r = sshbuf_get_u32(m, NULL)) != 0 || /* ignored */ 582 (r = sshbuf_get_bignum1(m, k->rsa->n)) != 0 || 583 (r = sshbuf_get_bignum1(m, k->rsa->e)) != 0 || 584 (r = sshbuf_get_bignum1(m, k->rsa->d)) != 0 || 585 (r = sshbuf_get_bignum1(m, k->rsa->iqmp)) != 0 || 586 /* SSH1 and SSL have p and q swapped */ 587 (r = sshbuf_get_bignum1(m, k->rsa->q)) != 0 || /* p */ 588 (r = sshbuf_get_bignum1(m, k->rsa->p)) != 0) /* q */ 589 goto out; 590 591 /* Generate additional parameters */ 592 if ((r = rsa_generate_additional_parameters(k->rsa)) != 0) 593 goto out; 594 /* enable blinding */ 595 if (RSA_blinding_on(k->rsa, NULL) != 1) { 596 r = SSH_ERR_LIBCRYPTO_ERROR; 597 goto out; 598 } 599 600 r = 0; /* success */ 601 out: 602 if (r == 0) 603 *kp = k; 604 else 605 sshkey_free(k); 606 return r; 607 } 608 #endif /* WITH_SSH1 */ 609 610 static void 611 process_add_identity(SocketEntry *e, int version) 612 { 613 Idtab *tab = idtab_lookup(version); 614 Identity *id; 615 int success = 0, confirm = 0; 616 u_int seconds; 617 char *comment = NULL; 618 time_t death = 0; 619 struct sshkey *k = NULL; 620 u_char ctype; 621 int r = SSH_ERR_INTERNAL_ERROR; 622 623 switch (version) { 624 #ifdef WITH_SSH1 625 case 1: 626 r = agent_decode_rsa1(e->request, &k); 627 break; 628 #endif /* WITH_SSH1 */ 629 case 2: 630 r = sshkey_private_deserialize(e->request, &k); 631 break; 632 } 633 if (r != 0 || k == NULL || 634 (r = sshbuf_get_cstring(e->request, &comment, NULL)) != 0) { 635 error("%s: decode private key: %s", __func__, ssh_err(r)); 636 goto err; 637 } 638 639 while (sshbuf_len(e->request)) { 640 if ((r = sshbuf_get_u8(e->request, &ctype)) != 0) { 641 error("%s: buffer error: %s", __func__, ssh_err(r)); 642 goto err; 643 } 644 switch (ctype) { 645 case SSH_AGENT_CONSTRAIN_LIFETIME: 646 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) { 647 error("%s: bad lifetime constraint: %s", 648 __func__, ssh_err(r)); 649 goto err; 650 } 651 death = monotime() + seconds; 652 break; 653 case SSH_AGENT_CONSTRAIN_CONFIRM: 654 confirm = 1; 655 break; 656 default: 657 error("%s: Unknown constraint %d", __func__, ctype); 658 err: 659 sshbuf_reset(e->request); 660 free(comment); 661 sshkey_free(k); 662 goto send; 663 } 664 } 665 666 success = 1; 667 if (lifetime && !death) 668 death = monotime() + lifetime; 669 if ((id = lookup_identity(k, version)) == NULL) { 670 id = xcalloc(1, sizeof(Identity)); 671 id->key = k; 672 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 673 /* Increment the number of identities. */ 674 tab->nentries++; 675 } else { 676 sshkey_free(k); 677 free(id->comment); 678 } 679 id->comment = comment; 680 id->death = death; 681 id->confirm = confirm; 682 send: 683 send_status(e, success); 684 } 685 686 /* XXX todo: encrypt sensitive data with passphrase */ 687 static void 688 process_lock_agent(SocketEntry *e, int lock) 689 { 690 int r, success = 0, delay; 691 char *passwd, passwdhash[LOCK_SIZE]; 692 static u_int fail_count = 0; 693 size_t pwlen; 694 695 if ((r = sshbuf_get_cstring(e->request, &passwd, &pwlen)) != 0) 696 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 697 if (pwlen == 0) { 698 debug("empty password not supported"); 699 } else if (locked && !lock) { 700 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 701 passwdhash, sizeof(passwdhash), LOCK_ROUNDS) < 0) 702 fatal("bcrypt_pbkdf"); 703 if (timingsafe_bcmp(passwdhash, lock_passwd, LOCK_SIZE) == 0) { 704 debug("agent unlocked"); 705 locked = 0; 706 fail_count = 0; 707 explicit_bzero(lock_passwd, sizeof(lock_passwd)); 708 success = 1; 709 } else { 710 /* delay in 0.1s increments up to 10s */ 711 if (fail_count < 100) 712 fail_count++; 713 delay = 100000 * fail_count; 714 debug("unlock failed, delaying %0.1lf seconds", 715 (double)delay/1000000); 716 usleep(delay); 717 } 718 explicit_bzero(passwdhash, sizeof(passwdhash)); 719 } else if (!locked && lock) { 720 debug("agent locked"); 721 locked = 1; 722 arc4random_buf(lock_salt, sizeof(lock_salt)); 723 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 724 lock_passwd, sizeof(lock_passwd), LOCK_ROUNDS) < 0) 725 fatal("bcrypt_pbkdf"); 726 success = 1; 727 } 728 explicit_bzero(passwd, pwlen); 729 free(passwd); 730 send_status(e, success); 731 } 732 733 static void 734 no_identities(SocketEntry *e, u_int type) 735 { 736 struct sshbuf *msg; 737 int r; 738 739 if ((msg = sshbuf_new()) == NULL) 740 fatal("%s: sshbuf_new failed", __func__); 741 if ((r = sshbuf_put_u8(msg, 742 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ? 743 SSH_AGENT_RSA_IDENTITIES_ANSWER : 744 SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 745 (r = sshbuf_put_u32(msg, 0)) != 0 || 746 (r = sshbuf_put_stringb(e->output, msg)) != 0) 747 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 748 sshbuf_free(msg); 749 } 750 751 #ifdef ENABLE_PKCS11 752 static void 753 process_add_smartcard_key(SocketEntry *e) 754 { 755 char *provider = NULL, *pin; 756 int r, i, version, count = 0, success = 0, confirm = 0; 757 u_int seconds; 758 time_t death = 0; 759 u_char type; 760 struct sshkey **keys = NULL, *k; 761 Identity *id; 762 Idtab *tab; 763 764 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 765 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) 766 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 767 768 while (sshbuf_len(e->request)) { 769 if ((r = sshbuf_get_u8(e->request, &type)) != 0) 770 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 771 switch (type) { 772 case SSH_AGENT_CONSTRAIN_LIFETIME: 773 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) 774 fatal("%s: buffer error: %s", 775 __func__, ssh_err(r)); 776 death = monotime() + seconds; 777 break; 778 case SSH_AGENT_CONSTRAIN_CONFIRM: 779 confirm = 1; 780 break; 781 default: 782 error("process_add_smartcard_key: " 783 "Unknown constraint type %d", type); 784 goto send; 785 } 786 } 787 if (lifetime && !death) 788 death = monotime() + lifetime; 789 790 count = pkcs11_add_provider(provider, pin, &keys); 791 for (i = 0; i < count; i++) { 792 k = keys[i]; 793 version = k->type == KEY_RSA1 ? 1 : 2; 794 tab = idtab_lookup(version); 795 if (lookup_identity(k, version) == NULL) { 796 id = xcalloc(1, sizeof(Identity)); 797 id->key = k; 798 id->provider = xstrdup(provider); 799 id->comment = xstrdup(provider); /* XXX */ 800 id->death = death; 801 id->confirm = confirm; 802 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 803 tab->nentries++; 804 success = 1; 805 } else { 806 sshkey_free(k); 807 } 808 keys[i] = NULL; 809 } 810 send: 811 free(pin); 812 free(provider); 813 free(keys); 814 send_status(e, success); 815 } 816 817 static void 818 process_remove_smartcard_key(SocketEntry *e) 819 { 820 char *provider = NULL, *pin = NULL; 821 int r, version, success = 0; 822 Identity *id, *nxt; 823 Idtab *tab; 824 825 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 826 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) 827 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 828 free(pin); 829 830 for (version = 1; version < 3; version++) { 831 tab = idtab_lookup(version); 832 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 833 nxt = TAILQ_NEXT(id, next); 834 /* Skip file--based keys */ 835 if (id->provider == NULL) 836 continue; 837 if (!strcmp(provider, id->provider)) { 838 TAILQ_REMOVE(&tab->idlist, id, next); 839 free_identity(id); 840 tab->nentries--; 841 } 842 } 843 } 844 if (pkcs11_del_provider(provider) == 0) 845 success = 1; 846 else 847 error("process_remove_smartcard_key:" 848 " pkcs11_del_provider failed"); 849 free(provider); 850 send_status(e, success); 851 } 852 #endif /* ENABLE_PKCS11 */ 853 854 /* dispatch incoming messages */ 855 856 static void 857 process_message(SocketEntry *e) 858 { 859 u_int msg_len; 860 u_char type; 861 const u_char *cp; 862 int r; 863 864 if (sshbuf_len(e->input) < 5) 865 return; /* Incomplete message. */ 866 cp = sshbuf_ptr(e->input); 867 msg_len = PEEK_U32(cp); 868 if (msg_len > 256 * 1024) { 869 close_socket(e); 870 return; 871 } 872 if (sshbuf_len(e->input) < msg_len + 4) 873 return; 874 875 /* move the current input to e->request */ 876 sshbuf_reset(e->request); 877 if ((r = sshbuf_get_stringb(e->input, e->request)) != 0 || 878 (r = sshbuf_get_u8(e->request, &type)) != 0) 879 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 880 881 /* check wheter agent is locked */ 882 if (locked && type != SSH_AGENTC_UNLOCK) { 883 sshbuf_reset(e->request); 884 switch (type) { 885 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 886 case SSH2_AGENTC_REQUEST_IDENTITIES: 887 /* send empty lists */ 888 no_identities(e, type); 889 break; 890 default: 891 /* send a fail message for all other request types */ 892 send_status(e, 0); 893 } 894 return; 895 } 896 897 debug("type %d", type); 898 switch (type) { 899 case SSH_AGENTC_LOCK: 900 case SSH_AGENTC_UNLOCK: 901 process_lock_agent(e, type == SSH_AGENTC_LOCK); 902 break; 903 #ifdef WITH_SSH1 904 /* ssh1 */ 905 case SSH_AGENTC_RSA_CHALLENGE: 906 process_authentication_challenge1(e); 907 break; 908 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 909 process_request_identities(e, 1); 910 break; 911 case SSH_AGENTC_ADD_RSA_IDENTITY: 912 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 913 process_add_identity(e, 1); 914 break; 915 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 916 process_remove_identity(e, 1); 917 break; 918 #endif 919 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 920 process_remove_all_identities(e, 1); /* safe for !WITH_SSH1 */ 921 break; 922 /* ssh2 */ 923 case SSH2_AGENTC_SIGN_REQUEST: 924 process_sign_request2(e); 925 break; 926 case SSH2_AGENTC_REQUEST_IDENTITIES: 927 process_request_identities(e, 2); 928 break; 929 case SSH2_AGENTC_ADD_IDENTITY: 930 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 931 process_add_identity(e, 2); 932 break; 933 case SSH2_AGENTC_REMOVE_IDENTITY: 934 process_remove_identity(e, 2); 935 break; 936 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 937 process_remove_all_identities(e, 2); 938 break; 939 #ifdef ENABLE_PKCS11 940 case SSH_AGENTC_ADD_SMARTCARD_KEY: 941 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 942 process_add_smartcard_key(e); 943 break; 944 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 945 process_remove_smartcard_key(e); 946 break; 947 #endif /* ENABLE_PKCS11 */ 948 default: 949 /* Unknown message. Respond with failure. */ 950 error("Unknown message %d", type); 951 sshbuf_reset(e->request); 952 send_status(e, 0); 953 break; 954 } 955 } 956 957 static void 958 new_socket(sock_type type, int fd) 959 { 960 u_int i, old_alloc, new_alloc; 961 962 if (type == AUTH_CONNECTION) { 963 debug("xcount %d -> %d", xcount, xcount + 1); 964 ++xcount; 965 } 966 set_nonblock(fd); 967 968 if (fd > max_fd) 969 max_fd = fd; 970 971 for (i = 0; i < sockets_alloc; i++) 972 if (sockets[i].type == AUTH_UNUSED) { 973 sockets[i].fd = fd; 974 if ((sockets[i].input = sshbuf_new()) == NULL) 975 fatal("%s: sshbuf_new failed", __func__); 976 if ((sockets[i].output = sshbuf_new()) == NULL) 977 fatal("%s: sshbuf_new failed", __func__); 978 if ((sockets[i].request = sshbuf_new()) == NULL) 979 fatal("%s: sshbuf_new failed", __func__); 980 sockets[i].type = type; 981 return; 982 } 983 old_alloc = sockets_alloc; 984 new_alloc = sockets_alloc + 10; 985 sockets = xreallocarray(sockets, new_alloc, sizeof(sockets[0])); 986 for (i = old_alloc; i < new_alloc; i++) 987 sockets[i].type = AUTH_UNUSED; 988 sockets_alloc = new_alloc; 989 sockets[old_alloc].fd = fd; 990 if ((sockets[old_alloc].input = sshbuf_new()) == NULL) 991 fatal("%s: sshbuf_new failed", __func__); 992 if ((sockets[old_alloc].output = sshbuf_new()) == NULL) 993 fatal("%s: sshbuf_new failed", __func__); 994 if ((sockets[old_alloc].request = sshbuf_new()) == NULL) 995 fatal("%s: sshbuf_new failed", __func__); 996 sockets[old_alloc].type = type; 997 } 998 999 static int 1000 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp, 1001 struct timeval **tvpp) 1002 { 1003 u_int i, sz; 1004 int n = 0; 1005 static struct timeval tv; 1006 time_t deadline; 1007 1008 for (i = 0; i < sockets_alloc; i++) { 1009 switch (sockets[i].type) { 1010 case AUTH_SOCKET: 1011 case AUTH_CONNECTION: 1012 n = MAX(n, sockets[i].fd); 1013 break; 1014 case AUTH_UNUSED: 1015 break; 1016 default: 1017 fatal("Unknown socket type %d", sockets[i].type); 1018 break; 1019 } 1020 } 1021 1022 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 1023 if (*fdrp == NULL || sz > *nallocp) { 1024 free(*fdrp); 1025 free(*fdwp); 1026 *fdrp = xmalloc(sz); 1027 *fdwp = xmalloc(sz); 1028 *nallocp = sz; 1029 } 1030 if (n < *fdl) 1031 debug("XXX shrink: %d < %d", n, *fdl); 1032 *fdl = n; 1033 memset(*fdrp, 0, sz); 1034 memset(*fdwp, 0, sz); 1035 1036 for (i = 0; i < sockets_alloc; i++) { 1037 switch (sockets[i].type) { 1038 case AUTH_SOCKET: 1039 case AUTH_CONNECTION: 1040 FD_SET(sockets[i].fd, *fdrp); 1041 if (sshbuf_len(sockets[i].output) > 0) 1042 FD_SET(sockets[i].fd, *fdwp); 1043 break; 1044 default: 1045 break; 1046 } 1047 } 1048 deadline = reaper(); 1049 if (parent_alive_interval != 0) 1050 deadline = (deadline == 0) ? parent_alive_interval : 1051 MIN(deadline, parent_alive_interval); 1052 if (deadline == 0) { 1053 *tvpp = NULL; 1054 } else { 1055 tv.tv_sec = deadline; 1056 tv.tv_usec = 0; 1057 *tvpp = &tv; 1058 } 1059 return (1); 1060 } 1061 1062 static void 1063 after_select(fd_set *readset, fd_set *writeset) 1064 { 1065 struct sockaddr_un sunaddr; 1066 socklen_t slen; 1067 char buf[1024]; 1068 int len, sock, r; 1069 u_int i, orig_alloc; 1070 uid_t euid; 1071 gid_t egid; 1072 1073 for (i = 0, orig_alloc = sockets_alloc; i < orig_alloc; i++) 1074 switch (sockets[i].type) { 1075 case AUTH_UNUSED: 1076 break; 1077 case AUTH_SOCKET: 1078 if (FD_ISSET(sockets[i].fd, readset)) { 1079 slen = sizeof(sunaddr); 1080 sock = accept(sockets[i].fd, 1081 (struct sockaddr *)&sunaddr, &slen); 1082 if (sock < 0) { 1083 error("accept from AUTH_SOCKET: %s", 1084 strerror(errno)); 1085 break; 1086 } 1087 if (getpeereid(sock, &euid, &egid) < 0) { 1088 error("getpeereid %d failed: %s", 1089 sock, strerror(errno)); 1090 close(sock); 1091 break; 1092 } 1093 if ((euid != 0) && (getuid() != euid)) { 1094 error("uid mismatch: " 1095 "peer euid %u != uid %u", 1096 (u_int) euid, (u_int) getuid()); 1097 close(sock); 1098 break; 1099 } 1100 new_socket(AUTH_CONNECTION, sock); 1101 } 1102 break; 1103 case AUTH_CONNECTION: 1104 if (sshbuf_len(sockets[i].output) > 0 && 1105 FD_ISSET(sockets[i].fd, writeset)) { 1106 len = write(sockets[i].fd, 1107 sshbuf_ptr(sockets[i].output), 1108 sshbuf_len(sockets[i].output)); 1109 if (len == -1 && (errno == EAGAIN || 1110 errno == EWOULDBLOCK || 1111 errno == EINTR)) 1112 continue; 1113 if (len <= 0) { 1114 close_socket(&sockets[i]); 1115 break; 1116 } 1117 if ((r = sshbuf_consume(sockets[i].output, 1118 len)) != 0) 1119 fatal("%s: buffer error: %s", 1120 __func__, ssh_err(r)); 1121 } 1122 if (FD_ISSET(sockets[i].fd, readset)) { 1123 len = read(sockets[i].fd, buf, sizeof(buf)); 1124 if (len == -1 && (errno == EAGAIN || 1125 errno == EWOULDBLOCK || 1126 errno == EINTR)) 1127 continue; 1128 if (len <= 0) { 1129 close_socket(&sockets[i]); 1130 break; 1131 } 1132 if ((r = sshbuf_put(sockets[i].input, 1133 buf, len)) != 0) 1134 fatal("%s: buffer error: %s", 1135 __func__, ssh_err(r)); 1136 explicit_bzero(buf, sizeof(buf)); 1137 process_message(&sockets[i]); 1138 } 1139 break; 1140 default: 1141 fatal("Unknown type %d", sockets[i].type); 1142 } 1143 } 1144 1145 static void 1146 cleanup_socket(void) 1147 { 1148 if (cleanup_pid != 0 && getpid() != cleanup_pid) 1149 return; 1150 debug("%s: cleanup", __func__); 1151 if (socket_name[0]) 1152 unlink(socket_name); 1153 if (socket_dir[0]) 1154 rmdir(socket_dir); 1155 } 1156 1157 void 1158 cleanup_exit(int i) 1159 { 1160 cleanup_socket(); 1161 _exit(i); 1162 } 1163 1164 /*ARGSUSED*/ 1165 static void 1166 cleanup_handler(int sig) 1167 { 1168 cleanup_socket(); 1169 #ifdef ENABLE_PKCS11 1170 pkcs11_terminate(); 1171 #endif 1172 _exit(2); 1173 } 1174 1175 static void 1176 check_parent_exists(void) 1177 { 1178 /* 1179 * If our parent has exited then getppid() will return (pid_t)1, 1180 * so testing for that should be safe. 1181 */ 1182 if (parent_pid != -1 && getppid() != parent_pid) { 1183 /* printf("Parent has died - Authentication agent exiting.\n"); */ 1184 cleanup_socket(); 1185 _exit(2); 1186 } 1187 } 1188 1189 static void 1190 usage(void) 1191 { 1192 fprintf(stderr, 1193 "usage: ssh-agent [-c | -s] [-Dd] [-a bind_address] [-E fingerprint_hash]\n" 1194 " [-t life] [command [arg ...]]\n" 1195 " ssh-agent [-c | -s] -k\n"); 1196 fprintf(stderr, " -x Exit when the last client disconnects.\n"); 1197 exit(1); 1198 } 1199 1200 int 1201 main(int ac, char **av) 1202 { 1203 int c_flag = 0, d_flag = 0, D_flag = 0, k_flag = 0, s_flag = 0; 1204 int sock, fd, ch, result, saved_errno; 1205 u_int nalloc; 1206 char *shell, *format, *pidstr, *agentsocket = NULL; 1207 fd_set *readsetp = NULL, *writesetp = NULL; 1208 #ifdef HAVE_SETRLIMIT 1209 struct rlimit rlim; 1210 #endif 1211 extern int optind; 1212 extern char *optarg; 1213 pid_t pid; 1214 char pidstrbuf[1 + 3 * sizeof pid]; 1215 struct timeval *tvp = NULL; 1216 size_t len; 1217 mode_t prev_mask; 1218 1219 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1220 sanitise_stdfd(); 1221 1222 /* drop */ 1223 setegid(getgid()); 1224 setgid(getgid()); 1225 setuid(geteuid()); 1226 1227 #if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE) 1228 /* Disable ptrace on Linux without sgid bit */ 1229 prctl(PR_SET_DUMPABLE, 0); 1230 #endif 1231 1232 #ifdef WITH_OPENSSL 1233 OpenSSL_add_all_algorithms(); 1234 #endif 1235 1236 __progname = ssh_get_progname(av[0]); 1237 seed_rng(); 1238 1239 while ((ch = getopt(ac, av, "cDdksE:a:t:x")) != -1) { 1240 switch (ch) { 1241 case 'E': 1242 fingerprint_hash = ssh_digest_alg_by_name(optarg); 1243 if (fingerprint_hash == -1) 1244 fatal("Invalid hash algorithm \"%s\"", optarg); 1245 break; 1246 case 'c': 1247 if (s_flag) 1248 usage(); 1249 c_flag++; 1250 break; 1251 case 'k': 1252 k_flag++; 1253 break; 1254 case 's': 1255 if (c_flag) 1256 usage(); 1257 s_flag++; 1258 break; 1259 case 'd': 1260 if (d_flag || D_flag) 1261 usage(); 1262 d_flag++; 1263 break; 1264 case 'D': 1265 if (d_flag || D_flag) 1266 usage(); 1267 D_flag++; 1268 break; 1269 case 'a': 1270 agentsocket = optarg; 1271 break; 1272 case 't': 1273 if ((lifetime = convtime(optarg)) == -1) { 1274 fprintf(stderr, "Invalid lifetime\n"); 1275 usage(); 1276 } 1277 break; 1278 case 'x': 1279 xcount = 0; 1280 break; 1281 default: 1282 usage(); 1283 } 1284 } 1285 ac -= optind; 1286 av += optind; 1287 1288 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag || D_flag)) 1289 usage(); 1290 1291 if (ac == 0 && !c_flag && !s_flag) { 1292 shell = getenv("SHELL"); 1293 if (shell != NULL && (len = strlen(shell)) > 2 && 1294 strncmp(shell + len - 3, "csh", 3) == 0) 1295 c_flag = 1; 1296 } 1297 if (k_flag) { 1298 const char *errstr = NULL; 1299 1300 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1301 if (pidstr == NULL) { 1302 fprintf(stderr, "%s not set, cannot kill agent\n", 1303 SSH_AGENTPID_ENV_NAME); 1304 exit(1); 1305 } 1306 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr); 1307 if (errstr) { 1308 fprintf(stderr, 1309 "%s=\"%s\", which is not a good PID: %s\n", 1310 SSH_AGENTPID_ENV_NAME, pidstr, errstr); 1311 exit(1); 1312 } 1313 if (kill(pid, SIGTERM) == -1) { 1314 perror("kill"); 1315 exit(1); 1316 } 1317 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 1318 printf(format, SSH_AUTHSOCKET_ENV_NAME); 1319 printf(format, SSH_AGENTPID_ENV_NAME); 1320 printf("echo Agent pid %ld killed;\n", (long)pid); 1321 exit(0); 1322 } 1323 parent_pid = getpid(); 1324 1325 if (agentsocket == NULL) { 1326 /* Create private directory for agent socket */ 1327 mktemp_proto(socket_dir, sizeof(socket_dir)); 1328 if (mkdtemp(socket_dir) == NULL) { 1329 perror("mkdtemp: private socket dir"); 1330 exit(1); 1331 } 1332 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1333 (long)parent_pid); 1334 } else { 1335 /* Try to use specified agent socket */ 1336 socket_dir[0] = '\0'; 1337 strlcpy(socket_name, agentsocket, sizeof socket_name); 1338 } 1339 1340 /* 1341 * Create socket early so it will exist before command gets run from 1342 * the parent. 1343 */ 1344 prev_mask = umask(0177); 1345 sock = unix_listener(socket_name, SSH_LISTEN_BACKLOG, 0); 1346 if (sock < 0) { 1347 /* XXX - unix_listener() calls error() not perror() */ 1348 *socket_name = '\0'; /* Don't unlink any existing file */ 1349 cleanup_exit(1); 1350 } 1351 umask(prev_mask); 1352 1353 /* 1354 * Fork, and have the parent execute the command, if any, or present 1355 * the socket data. The child continues as the authentication agent. 1356 */ 1357 if (D_flag || d_flag) { 1358 log_init(__progname, 1359 d_flag ? SYSLOG_LEVEL_DEBUG3 : SYSLOG_LEVEL_INFO, 1360 SYSLOG_FACILITY_AUTH, 1); 1361 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1362 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1363 SSH_AUTHSOCKET_ENV_NAME); 1364 printf("echo Agent pid %ld;\n", (long)parent_pid); 1365 goto skip; 1366 } 1367 pid = fork(); 1368 if (pid == -1) { 1369 perror("fork"); 1370 cleanup_exit(1); 1371 } 1372 if (pid != 0) { /* Parent - execute the given command. */ 1373 close(sock); 1374 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1375 if (ac == 0) { 1376 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1377 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1378 SSH_AUTHSOCKET_ENV_NAME); 1379 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 1380 SSH_AGENTPID_ENV_NAME); 1381 printf("echo Agent pid %ld;\n", (long)pid); 1382 exit(0); 1383 } 1384 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1385 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1386 perror("setenv"); 1387 exit(1); 1388 } 1389 execvp(av[0], av); 1390 perror(av[0]); 1391 exit(1); 1392 } 1393 /* child */ 1394 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1395 1396 if (setsid() == -1) { 1397 error("setsid: %s", strerror(errno)); 1398 cleanup_exit(1); 1399 } 1400 1401 (void)chdir("/"); 1402 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1403 /* XXX might close listen socket */ 1404 (void)dup2(fd, STDIN_FILENO); 1405 (void)dup2(fd, STDOUT_FILENO); 1406 (void)dup2(fd, STDERR_FILENO); 1407 if (fd > 2) 1408 close(fd); 1409 } 1410 1411 #ifdef HAVE_SETRLIMIT 1412 /* deny core dumps, since memory contains unencrypted private keys */ 1413 rlim.rlim_cur = rlim.rlim_max = 0; 1414 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 1415 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1416 cleanup_exit(1); 1417 } 1418 #endif 1419 1420 skip: 1421 1422 cleanup_pid = getpid(); 1423 1424 #ifdef ENABLE_PKCS11 1425 pkcs11_init(0); 1426 #endif 1427 new_socket(AUTH_SOCKET, sock); 1428 if (ac > 0) 1429 parent_alive_interval = 10; 1430 idtab_init(); 1431 signal(SIGPIPE, SIG_IGN); 1432 signal(SIGINT, (d_flag | D_flag) ? cleanup_handler : SIG_IGN); 1433 signal(SIGHUP, cleanup_handler); 1434 signal(SIGTERM, cleanup_handler); 1435 nalloc = 0; 1436 1437 while (1) { 1438 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp); 1439 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp); 1440 saved_errno = errno; 1441 if (parent_alive_interval != 0) 1442 check_parent_exists(); 1443 (void) reaper(); /* remove expired keys */ 1444 if (result < 0) { 1445 if (saved_errno == EINTR) 1446 continue; 1447 fatal("select: %s", strerror(saved_errno)); 1448 } else if (result > 0) 1449 after_select(readsetp, writesetp); 1450 } 1451 /* NOTREACHED */ 1452 } 1453