1 /* $OpenBSD: ssh-agent.c,v 1.204 2015/07/08 20:24:02 markus 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 "xmalloc.h" 77 #include "ssh.h" 78 #include "rsa.h" 79 #include "sshbuf.h" 80 #include "sshkey.h" 81 #include "authfd.h" 82 #include "compat.h" 83 #include "log.h" 84 #include "misc.h" 85 #include "digest.h" 86 #include "ssherr.h" 87 88 #ifdef ENABLE_PKCS11 89 #include "ssh-pkcs11.h" 90 #endif 91 92 #if defined(HAVE_SYS_PRCTL_H) 93 #include <sys/prctl.h> /* For prctl() and PR_SET_DUMPABLE */ 94 #endif 95 96 typedef enum { 97 AUTH_UNUSED, 98 AUTH_SOCKET, 99 AUTH_CONNECTION 100 } sock_type; 101 102 typedef struct { 103 int fd; 104 sock_type type; 105 struct sshbuf *input; 106 struct sshbuf *output; 107 struct sshbuf *request; 108 } SocketEntry; 109 110 u_int sockets_alloc = 0; 111 SocketEntry *sockets = NULL; 112 113 typedef struct identity { 114 TAILQ_ENTRY(identity) next; 115 struct sshkey *key; 116 char *comment; 117 char *provider; 118 time_t death; 119 u_int confirm; 120 } Identity; 121 122 typedef struct { 123 int nentries; 124 TAILQ_HEAD(idqueue, identity) idlist; 125 } Idtab; 126 127 /* private key table, one per protocol version */ 128 Idtab idtable[3]; 129 130 int max_fd = 0; 131 132 /* pid of shell == parent of agent */ 133 pid_t parent_pid = -1; 134 time_t parent_alive_interval = 0; 135 136 /* pid of process for which cleanup_socket is applicable */ 137 pid_t cleanup_pid = 0; 138 139 /* pathname and directory for AUTH_SOCKET */ 140 char socket_name[PATH_MAX]; 141 char socket_dir[PATH_MAX]; 142 143 /* locking */ 144 #define LOCK_SIZE 32 145 #define LOCK_SALT_SIZE 16 146 #define LOCK_ROUNDS 1 147 int locked = 0; 148 char lock_passwd[LOCK_SIZE]; 149 char lock_salt[LOCK_SALT_SIZE]; 150 151 extern char *__progname; 152 153 /* Default lifetime in seconds (0 == forever) */ 154 static long lifetime = 0; 155 156 static int fingerprint_hash = SSH_FP_HASH_DEFAULT; 157 158 /* 159 * Client connection count; incremented in new_socket() and decremented in 160 * close_socket(). When it reaches 0, ssh-agent will exit. Since it is 161 * normally initialized to 1, it will never reach 0. However, if the -x 162 * option is specified, it is initialized to 0 in main(); in that case, 163 * ssh-agent will exit as soon as it has had at least one client but no 164 * longer has any. 165 */ 166 static int xcount = 1; 167 168 static void 169 close_socket(SocketEntry *e) 170 { 171 int last = 0; 172 173 if (e->type == AUTH_CONNECTION) { 174 debug("xcount %d -> %d", xcount, xcount - 1); 175 if (--xcount == 0) 176 last = 1; 177 } 178 close(e->fd); 179 e->fd = -1; 180 e->type = AUTH_UNUSED; 181 sshbuf_free(e->input); 182 sshbuf_free(e->output); 183 sshbuf_free(e->request); 184 if (last) 185 cleanup_exit(0); 186 } 187 188 static void 189 idtab_init(void) 190 { 191 int i; 192 193 for (i = 0; i <=2; i++) { 194 TAILQ_INIT(&idtable[i].idlist); 195 idtable[i].nentries = 0; 196 } 197 } 198 199 /* return private key table for requested protocol version */ 200 static Idtab * 201 idtab_lookup(int version) 202 { 203 if (version < 1 || version > 2) 204 fatal("internal error, bad protocol version %d", version); 205 return &idtable[version]; 206 } 207 208 static void 209 free_identity(Identity *id) 210 { 211 sshkey_free(id->key); 212 free(id->provider); 213 free(id->comment); 214 free(id); 215 } 216 217 /* return matching private key for given public key */ 218 static Identity * 219 lookup_identity(struct sshkey *key, int version) 220 { 221 Identity *id; 222 223 Idtab *tab = idtab_lookup(version); 224 TAILQ_FOREACH(id, &tab->idlist, next) { 225 if (sshkey_equal(key, id->key)) 226 return (id); 227 } 228 return (NULL); 229 } 230 231 /* Check confirmation of keysign request */ 232 static int 233 confirm_key(Identity *id) 234 { 235 char *p; 236 int ret = -1; 237 238 p = sshkey_fingerprint(id->key, fingerprint_hash, SSH_FP_DEFAULT); 239 if (p != NULL && 240 ask_permission("Allow use of key %s?\nKey fingerprint %s.", 241 id->comment, p)) 242 ret = 0; 243 free(p); 244 245 return (ret); 246 } 247 248 static void 249 send_status(SocketEntry *e, int success) 250 { 251 int r; 252 253 if ((r = sshbuf_put_u32(e->output, 1)) != 0 || 254 (r = sshbuf_put_u8(e->output, success ? 255 SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0) 256 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 257 } 258 259 /* send list of supported public keys to 'client' */ 260 static void 261 process_request_identities(SocketEntry *e, int version) 262 { 263 Idtab *tab = idtab_lookup(version); 264 Identity *id; 265 struct sshbuf *msg; 266 int r; 267 268 if ((msg = sshbuf_new()) == NULL) 269 fatal("%s: sshbuf_new failed", __func__); 270 if ((r = sshbuf_put_u8(msg, (version == 1) ? 271 SSH_AGENT_RSA_IDENTITIES_ANSWER : 272 SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 273 (r = sshbuf_put_u32(msg, tab->nentries)) != 0) 274 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 275 TAILQ_FOREACH(id, &tab->idlist, next) { 276 if (id->key->type == KEY_RSA1) { 277 #ifdef WITH_SSH1 278 if ((r = sshbuf_put_u32(msg, 279 BN_num_bits(id->key->rsa->n))) != 0 || 280 (r = sshbuf_put_bignum1(msg, 281 id->key->rsa->e)) != 0 || 282 (r = sshbuf_put_bignum1(msg, 283 id->key->rsa->n)) != 0) 284 fatal("%s: buffer error: %s", 285 __func__, ssh_err(r)); 286 #endif 287 } else { 288 u_char *blob; 289 size_t blen; 290 291 if ((r = sshkey_to_blob(id->key, &blob, &blen)) != 0) { 292 error("%s: sshkey_to_blob: %s", __func__, 293 ssh_err(r)); 294 continue; 295 } 296 if ((r = sshbuf_put_string(msg, blob, blen)) != 0) 297 fatal("%s: buffer error: %s", 298 __func__, ssh_err(r)); 299 free(blob); 300 } 301 if ((r = sshbuf_put_cstring(msg, id->comment)) != 0) 302 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 303 } 304 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 305 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 306 sshbuf_free(msg); 307 } 308 309 #ifdef WITH_SSH1 310 /* ssh1 only */ 311 static void 312 process_authentication_challenge1(SocketEntry *e) 313 { 314 u_char buf[32], mdbuf[16], session_id[16]; 315 u_int response_type; 316 BIGNUM *challenge; 317 Identity *id; 318 int r, len; 319 struct sshbuf *msg; 320 struct ssh_digest_ctx *md; 321 struct sshkey *key; 322 323 if ((msg = sshbuf_new()) == NULL) 324 fatal("%s: sshbuf_new failed", __func__); 325 if ((key = sshkey_new(KEY_RSA1)) == NULL) 326 fatal("%s: sshkey_new failed", __func__); 327 if ((challenge = BN_new()) == NULL) 328 fatal("%s: BN_new failed", __func__); 329 330 if ((r = sshbuf_get_u32(e->request, NULL)) != 0 || /* ignored */ 331 (r = sshbuf_get_bignum1(e->request, key->rsa->e)) != 0 || 332 (r = sshbuf_get_bignum1(e->request, key->rsa->n)) != 0 || 333 (r = sshbuf_get_bignum1(e->request, challenge))) 334 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 335 336 /* Only protocol 1.1 is supported */ 337 if (sshbuf_len(e->request) == 0) 338 goto failure; 339 if ((r = sshbuf_get(e->request, session_id, sizeof(session_id))) != 0 || 340 (r = sshbuf_get_u32(e->request, &response_type)) != 0) 341 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 342 if (response_type != 1) 343 goto failure; 344 345 id = lookup_identity(key, 1); 346 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) { 347 struct sshkey *private = id->key; 348 /* Decrypt the challenge using the private key. */ 349 if ((r = rsa_private_decrypt(challenge, challenge, 350 private->rsa) != 0)) { 351 fatal("%s: rsa_public_encrypt: %s", __func__, 352 ssh_err(r)); 353 goto failure; /* XXX ? */ 354 } 355 356 /* The response is MD5 of decrypted challenge plus session id */ 357 len = BN_num_bytes(challenge); 358 if (len <= 0 || len > 32) { 359 logit("%s: bad challenge length %d", __func__, len); 360 goto failure; 361 } 362 memset(buf, 0, 32); 363 BN_bn2bin(challenge, buf + 32 - len); 364 if ((md = ssh_digest_start(SSH_DIGEST_MD5)) == NULL || 365 ssh_digest_update(md, buf, 32) < 0 || 366 ssh_digest_update(md, session_id, 16) < 0 || 367 ssh_digest_final(md, mdbuf, sizeof(mdbuf)) < 0) 368 fatal("%s: md5 failed", __func__); 369 ssh_digest_free(md); 370 371 /* Send the response. */ 372 if ((r = sshbuf_put_u8(msg, SSH_AGENT_RSA_RESPONSE)) != 0 || 373 (r = sshbuf_put(msg, mdbuf, sizeof(mdbuf))) != 0) 374 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 375 goto send; 376 } 377 378 failure: 379 /* Unknown identity or protocol error. Send failure. */ 380 if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0) 381 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 382 send: 383 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 384 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 385 sshkey_free(key); 386 BN_clear_free(challenge); 387 sshbuf_free(msg); 388 } 389 #endif 390 391 /* ssh2 only */ 392 static void 393 process_sign_request2(SocketEntry *e) 394 { 395 u_char *blob, *data, *signature = NULL; 396 size_t blen, dlen, slen = 0; 397 u_int compat = 0, flags; 398 int r, ok = -1; 399 struct sshbuf *msg; 400 struct sshkey *key; 401 struct identity *id; 402 403 if ((msg = sshbuf_new()) == NULL) 404 fatal("%s: sshbuf_new failed", __func__); 405 if ((r = sshbuf_get_string(e->request, &blob, &blen)) != 0 || 406 (r = sshbuf_get_string(e->request, &data, &dlen)) != 0 || 407 (r = sshbuf_get_u32(e->request, &flags)) != 0) 408 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 409 if (flags & SSH_AGENT_OLD_SIGNATURE) 410 compat = SSH_BUG_SIGBLOB; 411 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) { 412 error("%s: cannot parse key blob: %s", __func__, ssh_err(ok)); 413 goto send; 414 } 415 if ((id = lookup_identity(key, 2)) == NULL) { 416 verbose("%s: %s key not found", __func__, sshkey_type(key)); 417 goto send; 418 } 419 if (id->confirm && confirm_key(id) != 0) { 420 verbose("%s: user refused key", __func__); 421 goto send; 422 } 423 if ((r = sshkey_sign(id->key, &signature, &slen, 424 data, dlen, compat)) != 0) { 425 error("%s: sshkey_sign: %s", __func__, ssh_err(ok)); 426 goto send; 427 } 428 /* Success */ 429 ok = 0; 430 send: 431 sshkey_free(key); 432 if (ok == 0) { 433 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 || 434 (r = sshbuf_put_string(msg, signature, slen)) != 0) 435 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 436 } else if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0) 437 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 438 439 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 440 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 441 442 sshbuf_free(msg); 443 free(data); 444 free(blob); 445 free(signature); 446 } 447 448 /* shared */ 449 static void 450 process_remove_identity(SocketEntry *e, int version) 451 { 452 size_t blen; 453 int r, success = 0; 454 struct sshkey *key = NULL; 455 u_char *blob; 456 #ifdef WITH_SSH1 457 u_int bits; 458 #endif /* WITH_SSH1 */ 459 460 switch (version) { 461 #ifdef WITH_SSH1 462 case 1: 463 if ((key = sshkey_new(KEY_RSA1)) == NULL) { 464 error("%s: sshkey_new failed", __func__); 465 return; 466 } 467 if ((r = sshbuf_get_u32(e->request, &bits)) != 0 || 468 (r = sshbuf_get_bignum1(e->request, key->rsa->e)) != 0 || 469 (r = sshbuf_get_bignum1(e->request, key->rsa->n)) != 0) 470 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 471 472 if (bits != sshkey_size(key)) 473 logit("Warning: identity keysize mismatch: " 474 "actual %u, announced %u", 475 sshkey_size(key), bits); 476 break; 477 #endif /* WITH_SSH1 */ 478 case 2: 479 if ((r = sshbuf_get_string(e->request, &blob, &blen)) != 0) 480 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 481 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) 482 error("%s: sshkey_from_blob failed: %s", 483 __func__, ssh_err(r)); 484 free(blob); 485 break; 486 } 487 if (key != NULL) { 488 Identity *id = lookup_identity(key, version); 489 if (id != NULL) { 490 /* 491 * We have this key. Free the old key. Since we 492 * don't want to leave empty slots in the middle of 493 * the array, we actually free the key there and move 494 * all the entries between the empty slot and the end 495 * of the array. 496 */ 497 Idtab *tab = idtab_lookup(version); 498 if (tab->nentries < 1) 499 fatal("process_remove_identity: " 500 "internal error: tab->nentries %d", 501 tab->nentries); 502 TAILQ_REMOVE(&tab->idlist, id, next); 503 free_identity(id); 504 tab->nentries--; 505 success = 1; 506 } 507 sshkey_free(key); 508 } 509 send_status(e, success); 510 } 511 512 static void 513 process_remove_all_identities(SocketEntry *e, int version) 514 { 515 Idtab *tab = idtab_lookup(version); 516 Identity *id; 517 518 /* Loop over all identities and clear the keys. */ 519 for (id = TAILQ_FIRST(&tab->idlist); id; 520 id = TAILQ_FIRST(&tab->idlist)) { 521 TAILQ_REMOVE(&tab->idlist, id, next); 522 free_identity(id); 523 } 524 525 /* Mark that there are no identities. */ 526 tab->nentries = 0; 527 528 /* Send success. */ 529 send_status(e, 1); 530 } 531 532 /* removes expired keys and returns number of seconds until the next expiry */ 533 static time_t 534 reaper(void) 535 { 536 time_t deadline = 0, now = monotime(); 537 Identity *id, *nxt; 538 int version; 539 Idtab *tab; 540 541 for (version = 1; version < 3; version++) { 542 tab = idtab_lookup(version); 543 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 544 nxt = TAILQ_NEXT(id, next); 545 if (id->death == 0) 546 continue; 547 if (now >= id->death) { 548 debug("expiring key '%s'", id->comment); 549 TAILQ_REMOVE(&tab->idlist, id, next); 550 free_identity(id); 551 tab->nentries--; 552 } else 553 deadline = (deadline == 0) ? id->death : 554 MIN(deadline, id->death); 555 } 556 } 557 if (deadline == 0 || deadline <= now) 558 return 0; 559 else 560 return (deadline - now); 561 } 562 563 /* 564 * XXX this and the corresponding serialisation function probably belongs 565 * in key.c 566 */ 567 #ifdef WITH_SSH1 568 static int 569 agent_decode_rsa1(struct sshbuf *m, struct sshkey **kp) 570 { 571 struct sshkey *k = NULL; 572 int r = SSH_ERR_INTERNAL_ERROR; 573 574 *kp = NULL; 575 if ((k = sshkey_new_private(KEY_RSA1)) == NULL) 576 return SSH_ERR_ALLOC_FAIL; 577 578 if ((r = sshbuf_get_u32(m, NULL)) != 0 || /* ignored */ 579 (r = sshbuf_get_bignum1(m, k->rsa->n)) != 0 || 580 (r = sshbuf_get_bignum1(m, k->rsa->e)) != 0 || 581 (r = sshbuf_get_bignum1(m, k->rsa->d)) != 0 || 582 (r = sshbuf_get_bignum1(m, k->rsa->iqmp)) != 0 || 583 /* SSH1 and SSL have p and q swapped */ 584 (r = sshbuf_get_bignum1(m, k->rsa->q)) != 0 || /* p */ 585 (r = sshbuf_get_bignum1(m, k->rsa->p)) != 0) /* q */ 586 goto out; 587 588 /* Generate additional parameters */ 589 if ((r = rsa_generate_additional_parameters(k->rsa)) != 0) 590 goto out; 591 /* enable blinding */ 592 if (RSA_blinding_on(k->rsa, NULL) != 1) { 593 r = SSH_ERR_LIBCRYPTO_ERROR; 594 goto out; 595 } 596 597 r = 0; /* success */ 598 out: 599 if (r == 0) 600 *kp = k; 601 else 602 sshkey_free(k); 603 return r; 604 } 605 #endif /* WITH_SSH1 */ 606 607 static void 608 process_add_identity(SocketEntry *e, int version) 609 { 610 Idtab *tab = idtab_lookup(version); 611 Identity *id; 612 int success = 0, confirm = 0; 613 u_int seconds; 614 char *comment = NULL; 615 time_t death = 0; 616 struct sshkey *k = NULL; 617 u_char ctype; 618 int r = SSH_ERR_INTERNAL_ERROR; 619 620 switch (version) { 621 #ifdef WITH_SSH1 622 case 1: 623 r = agent_decode_rsa1(e->request, &k); 624 break; 625 #endif /* WITH_SSH1 */ 626 case 2: 627 r = sshkey_private_deserialize(e->request, &k); 628 break; 629 } 630 if (r != 0 || k == NULL || 631 (r = sshbuf_get_cstring(e->request, &comment, NULL)) != 0) { 632 error("%s: decode private key: %s", __func__, ssh_err(r)); 633 goto err; 634 } 635 636 while (sshbuf_len(e->request)) { 637 if ((r = sshbuf_get_u8(e->request, &ctype)) != 0) { 638 error("%s: buffer error: %s", __func__, ssh_err(r)); 639 goto err; 640 } 641 switch (ctype) { 642 case SSH_AGENT_CONSTRAIN_LIFETIME: 643 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) { 644 error("%s: bad lifetime constraint: %s", 645 __func__, ssh_err(r)); 646 goto err; 647 } 648 death = monotime() + seconds; 649 break; 650 case SSH_AGENT_CONSTRAIN_CONFIRM: 651 confirm = 1; 652 break; 653 default: 654 error("%s: Unknown constraint %d", __func__, ctype); 655 err: 656 sshbuf_reset(e->request); 657 free(comment); 658 sshkey_free(k); 659 goto send; 660 } 661 } 662 663 success = 1; 664 if (lifetime && !death) 665 death = monotime() + lifetime; 666 if ((id = lookup_identity(k, version)) == NULL) { 667 id = xcalloc(1, sizeof(Identity)); 668 id->key = k; 669 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 670 /* Increment the number of identities. */ 671 tab->nentries++; 672 } else { 673 sshkey_free(k); 674 free(id->comment); 675 } 676 id->comment = comment; 677 id->death = death; 678 id->confirm = confirm; 679 send: 680 send_status(e, success); 681 } 682 683 /* XXX todo: encrypt sensitive data with passphrase */ 684 static void 685 process_lock_agent(SocketEntry *e, int lock) 686 { 687 int r, success = 0, delay; 688 char *passwd, passwdhash[LOCK_SIZE]; 689 static u_int fail_count = 0; 690 size_t pwlen; 691 692 if ((r = sshbuf_get_cstring(e->request, &passwd, &pwlen)) != 0) 693 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 694 if (pwlen == 0) { 695 debug("empty password not supported"); 696 } else if (locked && !lock) { 697 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 698 passwdhash, sizeof(passwdhash), LOCK_ROUNDS) < 0) 699 fatal("bcrypt_pbkdf"); 700 if (timingsafe_bcmp(passwdhash, lock_passwd, LOCK_SIZE) == 0) { 701 debug("agent unlocked"); 702 locked = 0; 703 fail_count = 0; 704 explicit_bzero(lock_passwd, sizeof(lock_passwd)); 705 success = 1; 706 } else { 707 /* delay in 0.1s increments up to 10s */ 708 if (fail_count < 100) 709 fail_count++; 710 delay = 100000 * fail_count; 711 debug("unlock failed, delaying %0.1lf seconds", 712 (double)delay/1000000); 713 usleep(delay); 714 } 715 explicit_bzero(passwdhash, sizeof(passwdhash)); 716 } else if (!locked && lock) { 717 debug("agent locked"); 718 locked = 1; 719 arc4random_buf(lock_salt, sizeof(lock_salt)); 720 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 721 lock_passwd, sizeof(lock_passwd), LOCK_ROUNDS) < 0) 722 fatal("bcrypt_pbkdf"); 723 success = 1; 724 } 725 explicit_bzero(passwd, pwlen); 726 free(passwd); 727 send_status(e, success); 728 } 729 730 static void 731 no_identities(SocketEntry *e, u_int type) 732 { 733 struct sshbuf *msg; 734 int r; 735 736 if ((msg = sshbuf_new()) == NULL) 737 fatal("%s: sshbuf_new failed", __func__); 738 if ((r = sshbuf_put_u8(msg, 739 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ? 740 SSH_AGENT_RSA_IDENTITIES_ANSWER : 741 SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 742 (r = sshbuf_put_u32(msg, 0)) != 0 || 743 (r = sshbuf_put_stringb(e->output, msg)) != 0) 744 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 745 sshbuf_free(msg); 746 } 747 748 #ifdef ENABLE_PKCS11 749 static void 750 process_add_smartcard_key(SocketEntry *e) 751 { 752 char *provider = NULL, *pin; 753 int r, i, version, count = 0, success = 0, confirm = 0; 754 u_int seconds; 755 time_t death = 0; 756 u_char type; 757 struct sshkey **keys = NULL, *k; 758 Identity *id; 759 Idtab *tab; 760 761 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 762 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) 763 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 764 765 while (sshbuf_len(e->request)) { 766 if ((r = sshbuf_get_u8(e->request, &type)) != 0) 767 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 768 switch (type) { 769 case SSH_AGENT_CONSTRAIN_LIFETIME: 770 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) 771 fatal("%s: buffer error: %s", 772 __func__, ssh_err(r)); 773 death = monotime() + seconds; 774 break; 775 case SSH_AGENT_CONSTRAIN_CONFIRM: 776 confirm = 1; 777 break; 778 default: 779 error("process_add_smartcard_key: " 780 "Unknown constraint type %d", type); 781 goto send; 782 } 783 } 784 if (lifetime && !death) 785 death = monotime() + lifetime; 786 787 count = pkcs11_add_provider(provider, pin, &keys); 788 for (i = 0; i < count; i++) { 789 k = keys[i]; 790 version = k->type == KEY_RSA1 ? 1 : 2; 791 tab = idtab_lookup(version); 792 if (lookup_identity(k, version) == NULL) { 793 id = xcalloc(1, sizeof(Identity)); 794 id->key = k; 795 id->provider = xstrdup(provider); 796 id->comment = xstrdup(provider); /* XXX */ 797 id->death = death; 798 id->confirm = confirm; 799 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 800 tab->nentries++; 801 success = 1; 802 } else { 803 sshkey_free(k); 804 } 805 keys[i] = NULL; 806 } 807 send: 808 free(pin); 809 free(provider); 810 free(keys); 811 send_status(e, success); 812 } 813 814 static void 815 process_remove_smartcard_key(SocketEntry *e) 816 { 817 char *provider = NULL, *pin = NULL; 818 int r, version, success = 0; 819 Identity *id, *nxt; 820 Idtab *tab; 821 822 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 823 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) 824 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 825 free(pin); 826 827 for (version = 1; version < 3; version++) { 828 tab = idtab_lookup(version); 829 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 830 nxt = TAILQ_NEXT(id, next); 831 /* Skip file--based keys */ 832 if (id->provider == NULL) 833 continue; 834 if (!strcmp(provider, id->provider)) { 835 TAILQ_REMOVE(&tab->idlist, id, next); 836 free_identity(id); 837 tab->nentries--; 838 } 839 } 840 } 841 if (pkcs11_del_provider(provider) == 0) 842 success = 1; 843 else 844 error("process_remove_smartcard_key:" 845 " pkcs11_del_provider failed"); 846 free(provider); 847 send_status(e, success); 848 } 849 #endif /* ENABLE_PKCS11 */ 850 851 /* dispatch incoming messages */ 852 853 static void 854 process_message(SocketEntry *e) 855 { 856 u_int msg_len; 857 u_char type; 858 const u_char *cp; 859 int r; 860 861 if (sshbuf_len(e->input) < 5) 862 return; /* Incomplete message. */ 863 cp = sshbuf_ptr(e->input); 864 msg_len = PEEK_U32(cp); 865 if (msg_len > 256 * 1024) { 866 close_socket(e); 867 return; 868 } 869 if (sshbuf_len(e->input) < msg_len + 4) 870 return; 871 872 /* move the current input to e->request */ 873 sshbuf_reset(e->request); 874 if ((r = sshbuf_get_stringb(e->input, e->request)) != 0 || 875 (r = sshbuf_get_u8(e->request, &type)) != 0) 876 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 877 878 /* check wheter agent is locked */ 879 if (locked && type != SSH_AGENTC_UNLOCK) { 880 sshbuf_reset(e->request); 881 switch (type) { 882 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 883 case SSH2_AGENTC_REQUEST_IDENTITIES: 884 /* send empty lists */ 885 no_identities(e, type); 886 break; 887 default: 888 /* send a fail message for all other request types */ 889 send_status(e, 0); 890 } 891 return; 892 } 893 894 debug("type %d", type); 895 switch (type) { 896 case SSH_AGENTC_LOCK: 897 case SSH_AGENTC_UNLOCK: 898 process_lock_agent(e, type == SSH_AGENTC_LOCK); 899 break; 900 #ifdef WITH_SSH1 901 /* ssh1 */ 902 case SSH_AGENTC_RSA_CHALLENGE: 903 process_authentication_challenge1(e); 904 break; 905 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 906 process_request_identities(e, 1); 907 break; 908 case SSH_AGENTC_ADD_RSA_IDENTITY: 909 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 910 process_add_identity(e, 1); 911 break; 912 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 913 process_remove_identity(e, 1); 914 break; 915 #endif 916 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 917 process_remove_all_identities(e, 1); /* safe for !WITH_SSH1 */ 918 break; 919 /* ssh2 */ 920 case SSH2_AGENTC_SIGN_REQUEST: 921 process_sign_request2(e); 922 break; 923 case SSH2_AGENTC_REQUEST_IDENTITIES: 924 process_request_identities(e, 2); 925 break; 926 case SSH2_AGENTC_ADD_IDENTITY: 927 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 928 process_add_identity(e, 2); 929 break; 930 case SSH2_AGENTC_REMOVE_IDENTITY: 931 process_remove_identity(e, 2); 932 break; 933 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 934 process_remove_all_identities(e, 2); 935 break; 936 #ifdef ENABLE_PKCS11 937 case SSH_AGENTC_ADD_SMARTCARD_KEY: 938 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 939 process_add_smartcard_key(e); 940 break; 941 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 942 process_remove_smartcard_key(e); 943 break; 944 #endif /* ENABLE_PKCS11 */ 945 default: 946 /* Unknown message. Respond with failure. */ 947 error("Unknown message %d", type); 948 sshbuf_reset(e->request); 949 send_status(e, 0); 950 break; 951 } 952 } 953 954 static void 955 new_socket(sock_type type, int fd) 956 { 957 u_int i, old_alloc, new_alloc; 958 959 if (type == AUTH_CONNECTION) { 960 debug("xcount %d -> %d", xcount, xcount + 1); 961 ++xcount; 962 } 963 set_nonblock(fd); 964 965 if (fd > max_fd) 966 max_fd = fd; 967 968 for (i = 0; i < sockets_alloc; i++) 969 if (sockets[i].type == AUTH_UNUSED) { 970 sockets[i].fd = fd; 971 if ((sockets[i].input = sshbuf_new()) == NULL) 972 fatal("%s: sshbuf_new failed", __func__); 973 if ((sockets[i].output = sshbuf_new()) == NULL) 974 fatal("%s: sshbuf_new failed", __func__); 975 if ((sockets[i].request = sshbuf_new()) == NULL) 976 fatal("%s: sshbuf_new failed", __func__); 977 sockets[i].type = type; 978 return; 979 } 980 old_alloc = sockets_alloc; 981 new_alloc = sockets_alloc + 10; 982 sockets = xreallocarray(sockets, new_alloc, sizeof(sockets[0])); 983 for (i = old_alloc; i < new_alloc; i++) 984 sockets[i].type = AUTH_UNUSED; 985 sockets_alloc = new_alloc; 986 sockets[old_alloc].fd = fd; 987 if ((sockets[old_alloc].input = sshbuf_new()) == NULL) 988 fatal("%s: sshbuf_new failed", __func__); 989 if ((sockets[old_alloc].output = sshbuf_new()) == NULL) 990 fatal("%s: sshbuf_new failed", __func__); 991 if ((sockets[old_alloc].request = sshbuf_new()) == NULL) 992 fatal("%s: sshbuf_new failed", __func__); 993 sockets[old_alloc].type = type; 994 } 995 996 static int 997 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp, 998 struct timeval **tvpp) 999 { 1000 u_int i, sz; 1001 int n = 0; 1002 static struct timeval tv; 1003 time_t deadline; 1004 1005 for (i = 0; i < sockets_alloc; i++) { 1006 switch (sockets[i].type) { 1007 case AUTH_SOCKET: 1008 case AUTH_CONNECTION: 1009 n = MAX(n, sockets[i].fd); 1010 break; 1011 case AUTH_UNUSED: 1012 break; 1013 default: 1014 fatal("Unknown socket type %d", sockets[i].type); 1015 break; 1016 } 1017 } 1018 1019 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 1020 if (*fdrp == NULL || sz > *nallocp) { 1021 free(*fdrp); 1022 free(*fdwp); 1023 *fdrp = xmalloc(sz); 1024 *fdwp = xmalloc(sz); 1025 *nallocp = sz; 1026 } 1027 if (n < *fdl) 1028 debug("XXX shrink: %d < %d", n, *fdl); 1029 *fdl = n; 1030 memset(*fdrp, 0, sz); 1031 memset(*fdwp, 0, sz); 1032 1033 for (i = 0; i < sockets_alloc; i++) { 1034 switch (sockets[i].type) { 1035 case AUTH_SOCKET: 1036 case AUTH_CONNECTION: 1037 FD_SET(sockets[i].fd, *fdrp); 1038 if (sshbuf_len(sockets[i].output) > 0) 1039 FD_SET(sockets[i].fd, *fdwp); 1040 break; 1041 default: 1042 break; 1043 } 1044 } 1045 deadline = reaper(); 1046 if (parent_alive_interval != 0) 1047 deadline = (deadline == 0) ? parent_alive_interval : 1048 MIN(deadline, parent_alive_interval); 1049 if (deadline == 0) { 1050 *tvpp = NULL; 1051 } else { 1052 tv.tv_sec = deadline; 1053 tv.tv_usec = 0; 1054 *tvpp = &tv; 1055 } 1056 return (1); 1057 } 1058 1059 static void 1060 after_select(fd_set *readset, fd_set *writeset) 1061 { 1062 struct sockaddr_un sunaddr; 1063 socklen_t slen; 1064 char buf[1024]; 1065 int len, sock, r; 1066 u_int i, orig_alloc; 1067 uid_t euid; 1068 gid_t egid; 1069 1070 for (i = 0, orig_alloc = sockets_alloc; i < orig_alloc; i++) 1071 switch (sockets[i].type) { 1072 case AUTH_UNUSED: 1073 break; 1074 case AUTH_SOCKET: 1075 if (FD_ISSET(sockets[i].fd, readset)) { 1076 slen = sizeof(sunaddr); 1077 sock = accept(sockets[i].fd, 1078 (struct sockaddr *)&sunaddr, &slen); 1079 if (sock < 0) { 1080 error("accept from AUTH_SOCKET: %s", 1081 strerror(errno)); 1082 break; 1083 } 1084 if (getpeereid(sock, &euid, &egid) < 0) { 1085 error("getpeereid %d failed: %s", 1086 sock, strerror(errno)); 1087 close(sock); 1088 break; 1089 } 1090 if ((euid != 0) && (getuid() != euid)) { 1091 error("uid mismatch: " 1092 "peer euid %u != uid %u", 1093 (u_int) euid, (u_int) getuid()); 1094 close(sock); 1095 break; 1096 } 1097 new_socket(AUTH_CONNECTION, sock); 1098 } 1099 break; 1100 case AUTH_CONNECTION: 1101 if (sshbuf_len(sockets[i].output) > 0 && 1102 FD_ISSET(sockets[i].fd, writeset)) { 1103 len = write(sockets[i].fd, 1104 sshbuf_ptr(sockets[i].output), 1105 sshbuf_len(sockets[i].output)); 1106 if (len == -1 && (errno == EAGAIN || 1107 errno == EWOULDBLOCK || 1108 errno == EINTR)) 1109 continue; 1110 if (len <= 0) { 1111 close_socket(&sockets[i]); 1112 break; 1113 } 1114 if ((r = sshbuf_consume(sockets[i].output, 1115 len)) != 0) 1116 fatal("%s: buffer error: %s", 1117 __func__, ssh_err(r)); 1118 } 1119 if (FD_ISSET(sockets[i].fd, readset)) { 1120 len = read(sockets[i].fd, buf, sizeof(buf)); 1121 if (len == -1 && (errno == EAGAIN || 1122 errno == EWOULDBLOCK || 1123 errno == EINTR)) 1124 continue; 1125 if (len <= 0) { 1126 close_socket(&sockets[i]); 1127 break; 1128 } 1129 if ((r = sshbuf_put(sockets[i].input, 1130 buf, len)) != 0) 1131 fatal("%s: buffer error: %s", 1132 __func__, ssh_err(r)); 1133 explicit_bzero(buf, sizeof(buf)); 1134 process_message(&sockets[i]); 1135 } 1136 break; 1137 default: 1138 fatal("Unknown type %d", sockets[i].type); 1139 } 1140 } 1141 1142 static void 1143 cleanup_socket(void) 1144 { 1145 if (cleanup_pid != 0 && getpid() != cleanup_pid) 1146 return; 1147 debug("%s: cleanup", __func__); 1148 if (socket_name[0]) 1149 unlink(socket_name); 1150 if (socket_dir[0]) 1151 rmdir(socket_dir); 1152 } 1153 1154 void 1155 cleanup_exit(int i) 1156 { 1157 cleanup_socket(); 1158 _exit(i); 1159 } 1160 1161 /*ARGSUSED*/ 1162 static void 1163 cleanup_handler(int sig) 1164 { 1165 cleanup_socket(); 1166 #ifdef ENABLE_PKCS11 1167 pkcs11_terminate(); 1168 #endif 1169 _exit(2); 1170 } 1171 1172 static void 1173 check_parent_exists(void) 1174 { 1175 /* 1176 * If our parent has exited then getppid() will return (pid_t)1, 1177 * so testing for that should be safe. 1178 */ 1179 if (parent_pid != -1 && getppid() != parent_pid) { 1180 /* printf("Parent has died - Authentication agent exiting.\n"); */ 1181 cleanup_socket(); 1182 _exit(2); 1183 } 1184 } 1185 1186 static void 1187 usage(void) 1188 { 1189 fprintf(stderr, 1190 "usage: ssh-agent [-c | -s] [-Dd] [-a bind_address] [-E fingerprint_hash]\n" 1191 " [-t life] [command [arg ...]]\n" 1192 " ssh-agent [-c | -s] -k\n"); 1193 fprintf(stderr, " -x Exit when the last client disconnects.\n"); 1194 exit(1); 1195 } 1196 1197 int 1198 main(int ac, char **av) 1199 { 1200 int c_flag = 0, d_flag = 0, D_flag = 0, k_flag = 0, s_flag = 0; 1201 int sock, fd, ch, result, saved_errno; 1202 u_int nalloc; 1203 char *shell, *format, *pidstr, *agentsocket = NULL; 1204 fd_set *readsetp = NULL, *writesetp = NULL; 1205 #ifdef HAVE_SETRLIMIT 1206 struct rlimit rlim; 1207 #endif 1208 extern int optind; 1209 extern char *optarg; 1210 pid_t pid; 1211 char pidstrbuf[1 + 3 * sizeof pid]; 1212 struct timeval *tvp = NULL; 1213 size_t len; 1214 mode_t prev_mask; 1215 1216 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1217 sanitise_stdfd(); 1218 1219 /* drop */ 1220 setegid(getgid()); 1221 setgid(getgid()); 1222 setuid(geteuid()); 1223 1224 #if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE) 1225 /* Disable ptrace on Linux without sgid bit */ 1226 prctl(PR_SET_DUMPABLE, 0); 1227 #endif 1228 1229 #ifdef WITH_OPENSSL 1230 OpenSSL_add_all_algorithms(); 1231 #endif 1232 1233 __progname = ssh_get_progname(av[0]); 1234 seed_rng(); 1235 1236 while ((ch = getopt(ac, av, "cDdksE:a:t:x")) != -1) { 1237 switch (ch) { 1238 case 'E': 1239 fingerprint_hash = ssh_digest_alg_by_name(optarg); 1240 if (fingerprint_hash == -1) 1241 fatal("Invalid hash algorithm \"%s\"", optarg); 1242 break; 1243 case 'c': 1244 if (s_flag) 1245 usage(); 1246 c_flag++; 1247 break; 1248 case 'k': 1249 k_flag++; 1250 break; 1251 case 's': 1252 if (c_flag) 1253 usage(); 1254 s_flag++; 1255 break; 1256 case 'd': 1257 if (d_flag || D_flag) 1258 usage(); 1259 d_flag++; 1260 break; 1261 case 'D': 1262 if (d_flag || D_flag) 1263 usage(); 1264 D_flag++; 1265 break; 1266 case 'a': 1267 agentsocket = optarg; 1268 break; 1269 case 't': 1270 if ((lifetime = convtime(optarg)) == -1) { 1271 fprintf(stderr, "Invalid lifetime\n"); 1272 usage(); 1273 } 1274 break; 1275 case 'x': 1276 xcount = 0; 1277 break; 1278 default: 1279 usage(); 1280 } 1281 } 1282 ac -= optind; 1283 av += optind; 1284 1285 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag || D_flag)) 1286 usage(); 1287 1288 if (ac == 0 && !c_flag && !s_flag) { 1289 shell = getenv("SHELL"); 1290 if (shell != NULL && (len = strlen(shell)) > 2 && 1291 strncmp(shell + len - 3, "csh", 3) == 0) 1292 c_flag = 1; 1293 } 1294 if (k_flag) { 1295 const char *errstr = NULL; 1296 1297 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1298 if (pidstr == NULL) { 1299 fprintf(stderr, "%s not set, cannot kill agent\n", 1300 SSH_AGENTPID_ENV_NAME); 1301 exit(1); 1302 } 1303 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr); 1304 if (errstr) { 1305 fprintf(stderr, 1306 "%s=\"%s\", which is not a good PID: %s\n", 1307 SSH_AGENTPID_ENV_NAME, pidstr, errstr); 1308 exit(1); 1309 } 1310 if (kill(pid, SIGTERM) == -1) { 1311 perror("kill"); 1312 exit(1); 1313 } 1314 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 1315 printf(format, SSH_AUTHSOCKET_ENV_NAME); 1316 printf(format, SSH_AGENTPID_ENV_NAME); 1317 printf("echo Agent pid %ld killed;\n", (long)pid); 1318 exit(0); 1319 } 1320 parent_pid = getpid(); 1321 1322 if (agentsocket == NULL) { 1323 /* Create private directory for agent socket */ 1324 mktemp_proto(socket_dir, sizeof(socket_dir)); 1325 if (mkdtemp(socket_dir) == NULL) { 1326 perror("mkdtemp: private socket dir"); 1327 exit(1); 1328 } 1329 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1330 (long)parent_pid); 1331 } else { 1332 /* Try to use specified agent socket */ 1333 socket_dir[0] = '\0'; 1334 strlcpy(socket_name, agentsocket, sizeof socket_name); 1335 } 1336 1337 /* 1338 * Create socket early so it will exist before command gets run from 1339 * the parent. 1340 */ 1341 prev_mask = umask(0177); 1342 sock = unix_listener(socket_name, SSH_LISTEN_BACKLOG, 0); 1343 if (sock < 0) { 1344 /* XXX - unix_listener() calls error() not perror() */ 1345 *socket_name = '\0'; /* Don't unlink any existing file */ 1346 cleanup_exit(1); 1347 } 1348 umask(prev_mask); 1349 1350 /* 1351 * Fork, and have the parent execute the command, if any, or present 1352 * the socket data. The child continues as the authentication agent. 1353 */ 1354 if (D_flag || d_flag) { 1355 log_init(__progname, 1356 d_flag ? SYSLOG_LEVEL_DEBUG3 : SYSLOG_LEVEL_INFO, 1357 SYSLOG_FACILITY_AUTH, 1); 1358 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1359 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1360 SSH_AUTHSOCKET_ENV_NAME); 1361 printf("echo Agent pid %ld;\n", (long)parent_pid); 1362 goto skip; 1363 } 1364 pid = fork(); 1365 if (pid == -1) { 1366 perror("fork"); 1367 cleanup_exit(1); 1368 } 1369 if (pid != 0) { /* Parent - execute the given command. */ 1370 close(sock); 1371 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1372 if (ac == 0) { 1373 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1374 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1375 SSH_AUTHSOCKET_ENV_NAME); 1376 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 1377 SSH_AGENTPID_ENV_NAME); 1378 printf("echo Agent pid %ld;\n", (long)pid); 1379 exit(0); 1380 } 1381 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1382 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1383 perror("setenv"); 1384 exit(1); 1385 } 1386 execvp(av[0], av); 1387 perror(av[0]); 1388 exit(1); 1389 } 1390 /* child */ 1391 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1392 1393 if (setsid() == -1) { 1394 error("setsid: %s", strerror(errno)); 1395 cleanup_exit(1); 1396 } 1397 1398 (void)chdir("/"); 1399 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1400 /* XXX might close listen socket */ 1401 (void)dup2(fd, STDIN_FILENO); 1402 (void)dup2(fd, STDOUT_FILENO); 1403 (void)dup2(fd, STDERR_FILENO); 1404 if (fd > 2) 1405 close(fd); 1406 } 1407 1408 #ifdef HAVE_SETRLIMIT 1409 /* deny core dumps, since memory contains unencrypted private keys */ 1410 rlim.rlim_cur = rlim.rlim_max = 0; 1411 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 1412 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1413 cleanup_exit(1); 1414 } 1415 #endif 1416 1417 skip: 1418 1419 cleanup_pid = getpid(); 1420 1421 #ifdef ENABLE_PKCS11 1422 pkcs11_init(0); 1423 #endif 1424 new_socket(AUTH_SOCKET, sock); 1425 if (ac > 0) 1426 parent_alive_interval = 10; 1427 idtab_init(); 1428 signal(SIGPIPE, SIG_IGN); 1429 signal(SIGINT, (d_flag | D_flag) ? cleanup_handler : SIG_IGN); 1430 signal(SIGHUP, cleanup_handler); 1431 signal(SIGTERM, cleanup_handler); 1432 nalloc = 0; 1433 1434 while (1) { 1435 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp); 1436 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp); 1437 saved_errno = errno; 1438 if (parent_alive_interval != 0) 1439 check_parent_exists(); 1440 (void) reaper(); /* remove expired keys */ 1441 if (result < 0) { 1442 if (saved_errno == EINTR) 1443 continue; 1444 fatal("select: %s", strerror(saved_errno)); 1445 } else if (result > 0) 1446 after_select(readsetp, writesetp); 1447 } 1448 /* NOTREACHED */ 1449 } 1450