ssh-agent.c revision 323124
1/* $OpenBSD: ssh-agent.c,v 1.213 2016/05/02 08:49:03 djm 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: stable/10/crypto/openssh/ssh-agent.c 323124 2017-09-01 22:52:18Z des $"); 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 92typedef enum { 93 AUTH_UNUSED, 94 AUTH_SOCKET, 95 AUTH_CONNECTION 96} sock_type; 97 98typedef struct { 99 int fd; 100 sock_type type; 101 struct sshbuf *input; 102 struct sshbuf *output; 103 struct sshbuf *request; 104} SocketEntry; 105 106u_int sockets_alloc = 0; 107SocketEntry *sockets = NULL; 108 109typedef struct identity { 110 TAILQ_ENTRY(identity) next; 111 struct sshkey *key; 112 char *comment; 113 char *provider; 114 time_t death; 115 u_int confirm; 116} Identity; 117 118typedef struct { 119 int nentries; 120 TAILQ_HEAD(idqueue, identity) idlist; 121} Idtab; 122 123/* private key table, one per protocol version */ 124Idtab idtable[3]; 125 126int max_fd = 0; 127 128/* pid of shell == parent of agent */ 129pid_t parent_pid = -1; 130time_t parent_alive_interval = 0; 131 132/* pid of process for which cleanup_socket is applicable */ 133pid_t cleanup_pid = 0; 134 135/* pathname and directory for AUTH_SOCKET */ 136char socket_name[PATH_MAX]; 137char socket_dir[PATH_MAX]; 138 139/* locking */ 140#define LOCK_SIZE 32 141#define LOCK_SALT_SIZE 16 142#define LOCK_ROUNDS 1 143int locked = 0; 144u_char lock_pwhash[LOCK_SIZE]; 145u_char lock_salt[LOCK_SALT_SIZE]; 146 147extern char *__progname; 148 149/* Default lifetime in seconds (0 == forever) */ 150static long lifetime = 0; 151 152static int fingerprint_hash = SSH_FP_HASH_DEFAULT; 153 154/* 155 * Client connection count; incremented in new_socket() and decremented in 156 * close_socket(). When it reaches 0, ssh-agent will exit. Since it is 157 * normally initialized to 1, it will never reach 0. However, if the -x 158 * option is specified, it is initialized to 0 in main(); in that case, 159 * ssh-agent will exit as soon as it has had at least one client but no 160 * longer has any. 161 */ 162static int xcount = 1; 163 164static void 165close_socket(SocketEntry *e) 166{ 167 int last = 0; 168 169 if (e->type == AUTH_CONNECTION) { 170 debug("xcount %d -> %d", xcount, xcount - 1); 171 if (--xcount == 0) 172 last = 1; 173 } 174 close(e->fd); 175 e->fd = -1; 176 e->type = AUTH_UNUSED; 177 sshbuf_free(e->input); 178 sshbuf_free(e->output); 179 sshbuf_free(e->request); 180 if (last) 181 cleanup_exit(0); 182} 183 184static void 185idtab_init(void) 186{ 187 int i; 188 189 for (i = 0; i <=2; i++) { 190 TAILQ_INIT(&idtable[i].idlist); 191 idtable[i].nentries = 0; 192 } 193} 194 195/* return private key table for requested protocol version */ 196static Idtab * 197idtab_lookup(int version) 198{ 199 if (version < 1 || version > 2) 200 fatal("internal error, bad protocol version %d", version); 201 return &idtable[version]; 202} 203 204static void 205free_identity(Identity *id) 206{ 207 sshkey_free(id->key); 208 free(id->provider); 209 free(id->comment); 210 free(id); 211} 212 213/* return matching private key for given public key */ 214static Identity * 215lookup_identity(struct sshkey *key, int version) 216{ 217 Identity *id; 218 219 Idtab *tab = idtab_lookup(version); 220 TAILQ_FOREACH(id, &tab->idlist, next) { 221 if (sshkey_equal(key, id->key)) 222 return (id); 223 } 224 return (NULL); 225} 226 227/* Check confirmation of keysign request */ 228static int 229confirm_key(Identity *id) 230{ 231 char *p; 232 int ret = -1; 233 234 p = sshkey_fingerprint(id->key, fingerprint_hash, SSH_FP_DEFAULT); 235 if (p != NULL && 236 ask_permission("Allow use of key %s?\nKey fingerprint %s.", 237 id->comment, p)) 238 ret = 0; 239 free(p); 240 241 return (ret); 242} 243 244static void 245send_status(SocketEntry *e, int success) 246{ 247 int r; 248 249 if ((r = sshbuf_put_u32(e->output, 1)) != 0 || 250 (r = sshbuf_put_u8(e->output, success ? 251 SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0) 252 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 253} 254 255/* send list of supported public keys to 'client' */ 256static void 257process_request_identities(SocketEntry *e, int version) 258{ 259 Idtab *tab = idtab_lookup(version); 260 Identity *id; 261 struct sshbuf *msg; 262 int r; 263 264 if ((msg = sshbuf_new()) == NULL) 265 fatal("%s: sshbuf_new failed", __func__); 266 if ((r = sshbuf_put_u8(msg, (version == 1) ? 267 SSH_AGENT_RSA_IDENTITIES_ANSWER : 268 SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 269 (r = sshbuf_put_u32(msg, tab->nentries)) != 0) 270 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 271 TAILQ_FOREACH(id, &tab->idlist, next) { 272 if (id->key->type == KEY_RSA1) { 273#ifdef WITH_SSH1 274 if ((r = sshbuf_put_u32(msg, 275 BN_num_bits(id->key->rsa->n))) != 0 || 276 (r = sshbuf_put_bignum1(msg, 277 id->key->rsa->e)) != 0 || 278 (r = sshbuf_put_bignum1(msg, 279 id->key->rsa->n)) != 0) 280 fatal("%s: buffer error: %s", 281 __func__, ssh_err(r)); 282#endif 283 } else { 284 u_char *blob; 285 size_t blen; 286 287 if ((r = sshkey_to_blob(id->key, &blob, &blen)) != 0) { 288 error("%s: sshkey_to_blob: %s", __func__, 289 ssh_err(r)); 290 continue; 291 } 292 if ((r = sshbuf_put_string(msg, blob, blen)) != 0) 293 fatal("%s: buffer error: %s", 294 __func__, ssh_err(r)); 295 free(blob); 296 } 297 if ((r = sshbuf_put_cstring(msg, id->comment)) != 0) 298 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 299 } 300 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 301 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 302 sshbuf_free(msg); 303} 304 305#ifdef WITH_SSH1 306/* ssh1 only */ 307static void 308process_authentication_challenge1(SocketEntry *e) 309{ 310 u_char buf[32], mdbuf[16], session_id[16]; 311 u_int response_type; 312 BIGNUM *challenge; 313 Identity *id; 314 int r, len; 315 struct sshbuf *msg; 316 struct ssh_digest_ctx *md; 317 struct sshkey *key; 318 319 if ((msg = sshbuf_new()) == NULL) 320 fatal("%s: sshbuf_new failed", __func__); 321 if ((key = sshkey_new(KEY_RSA1)) == NULL) 322 fatal("%s: sshkey_new failed", __func__); 323 if ((challenge = BN_new()) == NULL) 324 fatal("%s: BN_new failed", __func__); 325 326 if ((r = sshbuf_get_u32(e->request, NULL)) != 0 || /* ignored */ 327 (r = sshbuf_get_bignum1(e->request, key->rsa->e)) != 0 || 328 (r = sshbuf_get_bignum1(e->request, key->rsa->n)) != 0 || 329 (r = sshbuf_get_bignum1(e->request, challenge))) 330 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 331 332 /* Only protocol 1.1 is supported */ 333 if (sshbuf_len(e->request) == 0) 334 goto failure; 335 if ((r = sshbuf_get(e->request, session_id, sizeof(session_id))) != 0 || 336 (r = sshbuf_get_u32(e->request, &response_type)) != 0) 337 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 338 if (response_type != 1) 339 goto failure; 340 341 id = lookup_identity(key, 1); 342 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) { 343 struct sshkey *private = id->key; 344 /* Decrypt the challenge using the private key. */ 345 if ((r = rsa_private_decrypt(challenge, challenge, 346 private->rsa) != 0)) { 347 fatal("%s: rsa_public_encrypt: %s", __func__, 348 ssh_err(r)); 349 goto failure; /* XXX ? */ 350 } 351 352 /* The response is MD5 of decrypted challenge plus session id */ 353 len = BN_num_bytes(challenge); 354 if (len <= 0 || len > 32) { 355 logit("%s: bad challenge length %d", __func__, len); 356 goto failure; 357 } 358 memset(buf, 0, 32); 359 BN_bn2bin(challenge, buf + 32 - len); 360 if ((md = ssh_digest_start(SSH_DIGEST_MD5)) == NULL || 361 ssh_digest_update(md, buf, 32) < 0 || 362 ssh_digest_update(md, session_id, 16) < 0 || 363 ssh_digest_final(md, mdbuf, sizeof(mdbuf)) < 0) 364 fatal("%s: md5 failed", __func__); 365 ssh_digest_free(md); 366 367 /* Send the response. */ 368 if ((r = sshbuf_put_u8(msg, SSH_AGENT_RSA_RESPONSE)) != 0 || 369 (r = sshbuf_put(msg, mdbuf, sizeof(mdbuf))) != 0) 370 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 371 goto send; 372 } 373 374 failure: 375 /* Unknown identity or protocol error. Send failure. */ 376 if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0) 377 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 378 send: 379 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 380 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 381 sshkey_free(key); 382 BN_clear_free(challenge); 383 sshbuf_free(msg); 384} 385#endif 386 387static char * 388agent_decode_alg(struct sshkey *key, u_int flags) 389{ 390 if (key->type == KEY_RSA) { 391 if (flags & SSH_AGENT_RSA_SHA2_256) 392 return "rsa-sha2-256"; 393 else if (flags & SSH_AGENT_RSA_SHA2_512) 394 return "rsa-sha2-512"; 395 } 396 return NULL; 397} 398 399/* ssh2 only */ 400static void 401process_sign_request2(SocketEntry *e) 402{ 403 u_char *blob, *data, *signature = NULL; 404 size_t blen, dlen, slen = 0; 405 u_int compat = 0, flags; 406 int r, ok = -1; 407 struct sshbuf *msg; 408 struct sshkey *key; 409 struct identity *id; 410 411 if ((msg = sshbuf_new()) == NULL) 412 fatal("%s: sshbuf_new failed", __func__); 413 if ((r = sshbuf_get_string(e->request, &blob, &blen)) != 0 || 414 (r = sshbuf_get_string(e->request, &data, &dlen)) != 0 || 415 (r = sshbuf_get_u32(e->request, &flags)) != 0) 416 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 417 if (flags & SSH_AGENT_OLD_SIGNATURE) 418 compat = SSH_BUG_SIGBLOB; 419 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) { 420 error("%s: cannot parse key blob: %s", __func__, ssh_err(r)); 421 goto send; 422 } 423 if ((id = lookup_identity(key, 2)) == NULL) { 424 verbose("%s: %s key not found", __func__, sshkey_type(key)); 425 goto send; 426 } 427 if (id->confirm && confirm_key(id) != 0) { 428 verbose("%s: user refused key", __func__); 429 goto send; 430 } 431 if ((r = sshkey_sign(id->key, &signature, &slen, 432 data, dlen, agent_decode_alg(key, flags), compat)) != 0) { 433 error("%s: sshkey_sign: %s", __func__, ssh_err(r)); 434 goto send; 435 } 436 /* Success */ 437 ok = 0; 438 send: 439 sshkey_free(key); 440 if (ok == 0) { 441 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 || 442 (r = sshbuf_put_string(msg, signature, slen)) != 0) 443 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 444 } else if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0) 445 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 446 447 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 448 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 449 450 sshbuf_free(msg); 451 free(data); 452 free(blob); 453 free(signature); 454} 455 456/* shared */ 457static void 458process_remove_identity(SocketEntry *e, int version) 459{ 460 size_t blen; 461 int r, success = 0; 462 struct sshkey *key = NULL; 463 u_char *blob; 464#ifdef WITH_SSH1 465 u_int bits; 466#endif /* WITH_SSH1 */ 467 468 switch (version) { 469#ifdef WITH_SSH1 470 case 1: 471 if ((key = sshkey_new(KEY_RSA1)) == NULL) { 472 error("%s: sshkey_new failed", __func__); 473 return; 474 } 475 if ((r = sshbuf_get_u32(e->request, &bits)) != 0 || 476 (r = sshbuf_get_bignum1(e->request, key->rsa->e)) != 0 || 477 (r = sshbuf_get_bignum1(e->request, key->rsa->n)) != 0) 478 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 479 480 if (bits != sshkey_size(key)) 481 logit("Warning: identity keysize mismatch: " 482 "actual %u, announced %u", 483 sshkey_size(key), bits); 484 break; 485#endif /* WITH_SSH1 */ 486 case 2: 487 if ((r = sshbuf_get_string(e->request, &blob, &blen)) != 0) 488 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 489 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) 490 error("%s: sshkey_from_blob failed: %s", 491 __func__, ssh_err(r)); 492 free(blob); 493 break; 494 } 495 if (key != NULL) { 496 Identity *id = lookup_identity(key, version); 497 if (id != NULL) { 498 /* 499 * We have this key. Free the old key. Since we 500 * don't want to leave empty slots in the middle of 501 * the array, we actually free the key there and move 502 * all the entries between the empty slot and the end 503 * of the array. 504 */ 505 Idtab *tab = idtab_lookup(version); 506 if (tab->nentries < 1) 507 fatal("process_remove_identity: " 508 "internal error: tab->nentries %d", 509 tab->nentries); 510 TAILQ_REMOVE(&tab->idlist, id, next); 511 free_identity(id); 512 tab->nentries--; 513 success = 1; 514 } 515 sshkey_free(key); 516 } 517 send_status(e, success); 518} 519 520static void 521process_remove_all_identities(SocketEntry *e, int version) 522{ 523 Idtab *tab = idtab_lookup(version); 524 Identity *id; 525 526 /* Loop over all identities and clear the keys. */ 527 for (id = TAILQ_FIRST(&tab->idlist); id; 528 id = TAILQ_FIRST(&tab->idlist)) { 529 TAILQ_REMOVE(&tab->idlist, id, next); 530 free_identity(id); 531 } 532 533 /* Mark that there are no identities. */ 534 tab->nentries = 0; 535 536 /* Send success. */ 537 send_status(e, 1); 538} 539 540/* removes expired keys and returns number of seconds until the next expiry */ 541static time_t 542reaper(void) 543{ 544 time_t deadline = 0, now = monotime(); 545 Identity *id, *nxt; 546 int version; 547 Idtab *tab; 548 549 for (version = 1; version < 3; version++) { 550 tab = idtab_lookup(version); 551 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 552 nxt = TAILQ_NEXT(id, next); 553 if (id->death == 0) 554 continue; 555 if (now >= id->death) { 556 debug("expiring key '%s'", id->comment); 557 TAILQ_REMOVE(&tab->idlist, id, next); 558 free_identity(id); 559 tab->nentries--; 560 } else 561 deadline = (deadline == 0) ? id->death : 562 MIN(deadline, id->death); 563 } 564 } 565 if (deadline == 0 || deadline <= now) 566 return 0; 567 else 568 return (deadline - now); 569} 570 571/* 572 * XXX this and the corresponding serialisation function probably belongs 573 * in key.c 574 */ 575#ifdef WITH_SSH1 576static int 577agent_decode_rsa1(struct sshbuf *m, struct sshkey **kp) 578{ 579 struct sshkey *k = NULL; 580 int r = SSH_ERR_INTERNAL_ERROR; 581 582 *kp = NULL; 583 if ((k = sshkey_new_private(KEY_RSA1)) == NULL) 584 return SSH_ERR_ALLOC_FAIL; 585 586 if ((r = sshbuf_get_u32(m, NULL)) != 0 || /* ignored */ 587 (r = sshbuf_get_bignum1(m, k->rsa->n)) != 0 || 588 (r = sshbuf_get_bignum1(m, k->rsa->e)) != 0 || 589 (r = sshbuf_get_bignum1(m, k->rsa->d)) != 0 || 590 (r = sshbuf_get_bignum1(m, k->rsa->iqmp)) != 0 || 591 /* SSH1 and SSL have p and q swapped */ 592 (r = sshbuf_get_bignum1(m, k->rsa->q)) != 0 || /* p */ 593 (r = sshbuf_get_bignum1(m, k->rsa->p)) != 0) /* q */ 594 goto out; 595 596 /* Generate additional parameters */ 597 if ((r = rsa_generate_additional_parameters(k->rsa)) != 0) 598 goto out; 599 /* enable blinding */ 600 if (RSA_blinding_on(k->rsa, NULL) != 1) { 601 r = SSH_ERR_LIBCRYPTO_ERROR; 602 goto out; 603 } 604 605 r = 0; /* success */ 606 out: 607 if (r == 0) 608 *kp = k; 609 else 610 sshkey_free(k); 611 return r; 612} 613#endif /* WITH_SSH1 */ 614 615static void 616process_add_identity(SocketEntry *e, int version) 617{ 618 Idtab *tab = idtab_lookup(version); 619 Identity *id; 620 int success = 0, confirm = 0; 621 u_int seconds; 622 char *comment = NULL; 623 time_t death = 0; 624 struct sshkey *k = NULL; 625 u_char ctype; 626 int r = SSH_ERR_INTERNAL_ERROR; 627 628 switch (version) { 629#ifdef WITH_SSH1 630 case 1: 631 r = agent_decode_rsa1(e->request, &k); 632 break; 633#endif /* WITH_SSH1 */ 634 case 2: 635 r = sshkey_private_deserialize(e->request, &k); 636 break; 637 } 638 if (r != 0 || k == NULL || 639 (r = sshbuf_get_cstring(e->request, &comment, NULL)) != 0) { 640 error("%s: decode private key: %s", __func__, ssh_err(r)); 641 goto err; 642 } 643 644 while (sshbuf_len(e->request)) { 645 if ((r = sshbuf_get_u8(e->request, &ctype)) != 0) { 646 error("%s: buffer error: %s", __func__, ssh_err(r)); 647 goto err; 648 } 649 switch (ctype) { 650 case SSH_AGENT_CONSTRAIN_LIFETIME: 651 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) { 652 error("%s: bad lifetime constraint: %s", 653 __func__, ssh_err(r)); 654 goto err; 655 } 656 death = monotime() + seconds; 657 break; 658 case SSH_AGENT_CONSTRAIN_CONFIRM: 659 confirm = 1; 660 break; 661 default: 662 error("%s: Unknown constraint %d", __func__, ctype); 663 err: 664 sshbuf_reset(e->request); 665 free(comment); 666 sshkey_free(k); 667 goto send; 668 } 669 } 670 671 success = 1; 672 if (lifetime && !death) 673 death = monotime() + lifetime; 674 if ((id = lookup_identity(k, version)) == NULL) { 675 id = xcalloc(1, sizeof(Identity)); 676 id->key = k; 677 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 678 /* Increment the number of identities. */ 679 tab->nentries++; 680 } else { 681 sshkey_free(k); 682 free(id->comment); 683 } 684 id->comment = comment; 685 id->death = death; 686 id->confirm = confirm; 687send: 688 send_status(e, success); 689} 690 691/* XXX todo: encrypt sensitive data with passphrase */ 692static void 693process_lock_agent(SocketEntry *e, int lock) 694{ 695 int r, success = 0, delay; 696 char *passwd; 697 u_char passwdhash[LOCK_SIZE]; 698 static u_int fail_count = 0; 699 size_t pwlen; 700 701 if ((r = sshbuf_get_cstring(e->request, &passwd, &pwlen)) != 0) 702 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 703 if (pwlen == 0) { 704 debug("empty password not supported"); 705 } else if (locked && !lock) { 706 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 707 passwdhash, sizeof(passwdhash), LOCK_ROUNDS) < 0) 708 fatal("bcrypt_pbkdf"); 709 if (timingsafe_bcmp(passwdhash, lock_pwhash, LOCK_SIZE) == 0) { 710 debug("agent unlocked"); 711 locked = 0; 712 fail_count = 0; 713 explicit_bzero(lock_pwhash, sizeof(lock_pwhash)); 714 success = 1; 715 } else { 716 /* delay in 0.1s increments up to 10s */ 717 if (fail_count < 100) 718 fail_count++; 719 delay = 100000 * fail_count; 720 debug("unlock failed, delaying %0.1lf seconds", 721 (double)delay/1000000); 722 usleep(delay); 723 } 724 explicit_bzero(passwdhash, sizeof(passwdhash)); 725 } else if (!locked && lock) { 726 debug("agent locked"); 727 locked = 1; 728 arc4random_buf(lock_salt, sizeof(lock_salt)); 729 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 730 lock_pwhash, sizeof(lock_pwhash), LOCK_ROUNDS) < 0) 731 fatal("bcrypt_pbkdf"); 732 success = 1; 733 } 734 explicit_bzero(passwd, pwlen); 735 free(passwd); 736 send_status(e, success); 737} 738 739static void 740no_identities(SocketEntry *e, u_int type) 741{ 742 struct sshbuf *msg; 743 int r; 744 745 if ((msg = sshbuf_new()) == NULL) 746 fatal("%s: sshbuf_new failed", __func__); 747 if ((r = sshbuf_put_u8(msg, 748 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ? 749 SSH_AGENT_RSA_IDENTITIES_ANSWER : 750 SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 751 (r = sshbuf_put_u32(msg, 0)) != 0 || 752 (r = sshbuf_put_stringb(e->output, msg)) != 0) 753 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 754 sshbuf_free(msg); 755} 756 757#ifdef ENABLE_PKCS11 758static void 759process_add_smartcard_key(SocketEntry *e) 760{ 761 char *provider = NULL, *pin; 762 int r, i, version, count = 0, success = 0, confirm = 0; 763 u_int seconds; 764 time_t death = 0; 765 u_char type; 766 struct sshkey **keys = NULL, *k; 767 Identity *id; 768 Idtab *tab; 769 770 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 771 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) 772 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 773 774 while (sshbuf_len(e->request)) { 775 if ((r = sshbuf_get_u8(e->request, &type)) != 0) 776 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 777 switch (type) { 778 case SSH_AGENT_CONSTRAIN_LIFETIME: 779 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) 780 fatal("%s: buffer error: %s", 781 __func__, ssh_err(r)); 782 death = monotime() + seconds; 783 break; 784 case SSH_AGENT_CONSTRAIN_CONFIRM: 785 confirm = 1; 786 break; 787 default: 788 error("process_add_smartcard_key: " 789 "Unknown constraint type %d", type); 790 goto send; 791 } 792 } 793 if (lifetime && !death) 794 death = monotime() + lifetime; 795 796 count = pkcs11_add_provider(provider, pin, &keys); 797 for (i = 0; i < count; i++) { 798 k = keys[i]; 799 version = k->type == KEY_RSA1 ? 1 : 2; 800 tab = idtab_lookup(version); 801 if (lookup_identity(k, version) == NULL) { 802 id = xcalloc(1, sizeof(Identity)); 803 id->key = k; 804 id->provider = xstrdup(provider); 805 id->comment = xstrdup(provider); /* XXX */ 806 id->death = death; 807 id->confirm = confirm; 808 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 809 tab->nentries++; 810 success = 1; 811 } else { 812 sshkey_free(k); 813 } 814 keys[i] = NULL; 815 } 816send: 817 free(pin); 818 free(provider); 819 free(keys); 820 send_status(e, success); 821} 822 823static void 824process_remove_smartcard_key(SocketEntry *e) 825{ 826 char *provider = NULL, *pin = NULL; 827 int r, version, success = 0; 828 Identity *id, *nxt; 829 Idtab *tab; 830 831 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 832 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) 833 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 834 free(pin); 835 836 for (version = 1; version < 3; version++) { 837 tab = idtab_lookup(version); 838 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 839 nxt = TAILQ_NEXT(id, next); 840 /* Skip file--based keys */ 841 if (id->provider == NULL) 842 continue; 843 if (!strcmp(provider, id->provider)) { 844 TAILQ_REMOVE(&tab->idlist, id, next); 845 free_identity(id); 846 tab->nentries--; 847 } 848 } 849 } 850 if (pkcs11_del_provider(provider) == 0) 851 success = 1; 852 else 853 error("process_remove_smartcard_key:" 854 " pkcs11_del_provider failed"); 855 free(provider); 856 send_status(e, success); 857} 858#endif /* ENABLE_PKCS11 */ 859 860/* dispatch incoming messages */ 861 862static void 863process_message(SocketEntry *e) 864{ 865 u_int msg_len; 866 u_char type; 867 const u_char *cp; 868 int r; 869 870 if (sshbuf_len(e->input) < 5) 871 return; /* Incomplete message. */ 872 cp = sshbuf_ptr(e->input); 873 msg_len = PEEK_U32(cp); 874 if (msg_len > 256 * 1024) { 875 close_socket(e); 876 return; 877 } 878 if (sshbuf_len(e->input) < msg_len + 4) 879 return; 880 881 /* move the current input to e->request */ 882 sshbuf_reset(e->request); 883 if ((r = sshbuf_get_stringb(e->input, e->request)) != 0 || 884 (r = sshbuf_get_u8(e->request, &type)) != 0) 885 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 886 887 /* check wheter agent is locked */ 888 if (locked && type != SSH_AGENTC_UNLOCK) { 889 sshbuf_reset(e->request); 890 switch (type) { 891 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 892 case SSH2_AGENTC_REQUEST_IDENTITIES: 893 /* send empty lists */ 894 no_identities(e, type); 895 break; 896 default: 897 /* send a fail message for all other request types */ 898 send_status(e, 0); 899 } 900 return; 901 } 902 903 debug("type %d", type); 904 switch (type) { 905 case SSH_AGENTC_LOCK: 906 case SSH_AGENTC_UNLOCK: 907 process_lock_agent(e, type == SSH_AGENTC_LOCK); 908 break; 909#ifdef WITH_SSH1 910 /* ssh1 */ 911 case SSH_AGENTC_RSA_CHALLENGE: 912 process_authentication_challenge1(e); 913 break; 914 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 915 process_request_identities(e, 1); 916 break; 917 case SSH_AGENTC_ADD_RSA_IDENTITY: 918 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 919 process_add_identity(e, 1); 920 break; 921 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 922 process_remove_identity(e, 1); 923 break; 924#endif 925 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 926 process_remove_all_identities(e, 1); /* safe for !WITH_SSH1 */ 927 break; 928 /* ssh2 */ 929 case SSH2_AGENTC_SIGN_REQUEST: 930 process_sign_request2(e); 931 break; 932 case SSH2_AGENTC_REQUEST_IDENTITIES: 933 process_request_identities(e, 2); 934 break; 935 case SSH2_AGENTC_ADD_IDENTITY: 936 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 937 process_add_identity(e, 2); 938 break; 939 case SSH2_AGENTC_REMOVE_IDENTITY: 940 process_remove_identity(e, 2); 941 break; 942 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 943 process_remove_all_identities(e, 2); 944 break; 945#ifdef ENABLE_PKCS11 946 case SSH_AGENTC_ADD_SMARTCARD_KEY: 947 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 948 process_add_smartcard_key(e); 949 break; 950 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 951 process_remove_smartcard_key(e); 952 break; 953#endif /* ENABLE_PKCS11 */ 954 default: 955 /* Unknown message. Respond with failure. */ 956 error("Unknown message %d", type); 957 sshbuf_reset(e->request); 958 send_status(e, 0); 959 break; 960 } 961} 962 963static void 964new_socket(sock_type type, int fd) 965{ 966 u_int i, old_alloc, new_alloc; 967 968 if (type == AUTH_CONNECTION) { 969 debug("xcount %d -> %d", xcount, xcount + 1); 970 ++xcount; 971 } 972 set_nonblock(fd); 973 974 if (fd > max_fd) 975 max_fd = fd; 976 977 for (i = 0; i < sockets_alloc; i++) 978 if (sockets[i].type == AUTH_UNUSED) { 979 sockets[i].fd = fd; 980 if ((sockets[i].input = sshbuf_new()) == NULL) 981 fatal("%s: sshbuf_new failed", __func__); 982 if ((sockets[i].output = sshbuf_new()) == NULL) 983 fatal("%s: sshbuf_new failed", __func__); 984 if ((sockets[i].request = sshbuf_new()) == NULL) 985 fatal("%s: sshbuf_new failed", __func__); 986 sockets[i].type = type; 987 return; 988 } 989 old_alloc = sockets_alloc; 990 new_alloc = sockets_alloc + 10; 991 sockets = xreallocarray(sockets, new_alloc, sizeof(sockets[0])); 992 for (i = old_alloc; i < new_alloc; i++) 993 sockets[i].type = AUTH_UNUSED; 994 sockets_alloc = new_alloc; 995 sockets[old_alloc].fd = fd; 996 if ((sockets[old_alloc].input = sshbuf_new()) == NULL) 997 fatal("%s: sshbuf_new failed", __func__); 998 if ((sockets[old_alloc].output = sshbuf_new()) == NULL) 999 fatal("%s: sshbuf_new failed", __func__); 1000 if ((sockets[old_alloc].request = sshbuf_new()) == NULL) 1001 fatal("%s: sshbuf_new failed", __func__); 1002 sockets[old_alloc].type = type; 1003} 1004 1005static int 1006prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp, 1007 struct timeval **tvpp) 1008{ 1009 u_int i, sz; 1010 int n = 0; 1011 static struct timeval tv; 1012 time_t deadline; 1013 1014 for (i = 0; i < sockets_alloc; i++) { 1015 switch (sockets[i].type) { 1016 case AUTH_SOCKET: 1017 case AUTH_CONNECTION: 1018 n = MAX(n, sockets[i].fd); 1019 break; 1020 case AUTH_UNUSED: 1021 break; 1022 default: 1023 fatal("Unknown socket type %d", sockets[i].type); 1024 break; 1025 } 1026 } 1027 1028 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 1029 if (*fdrp == NULL || sz > *nallocp) { 1030 free(*fdrp); 1031 free(*fdwp); 1032 *fdrp = xmalloc(sz); 1033 *fdwp = xmalloc(sz); 1034 *nallocp = sz; 1035 } 1036 if (n < *fdl) 1037 debug("XXX shrink: %d < %d", n, *fdl); 1038 *fdl = n; 1039 memset(*fdrp, 0, sz); 1040 memset(*fdwp, 0, sz); 1041 1042 for (i = 0; i < sockets_alloc; i++) { 1043 switch (sockets[i].type) { 1044 case AUTH_SOCKET: 1045 case AUTH_CONNECTION: 1046 FD_SET(sockets[i].fd, *fdrp); 1047 if (sshbuf_len(sockets[i].output) > 0) 1048 FD_SET(sockets[i].fd, *fdwp); 1049 break; 1050 default: 1051 break; 1052 } 1053 } 1054 deadline = reaper(); 1055 if (parent_alive_interval != 0) 1056 deadline = (deadline == 0) ? parent_alive_interval : 1057 MIN(deadline, parent_alive_interval); 1058 if (deadline == 0) { 1059 *tvpp = NULL; 1060 } else { 1061 tv.tv_sec = deadline; 1062 tv.tv_usec = 0; 1063 *tvpp = &tv; 1064 } 1065 return (1); 1066} 1067 1068static void 1069after_select(fd_set *readset, fd_set *writeset) 1070{ 1071 struct sockaddr_un sunaddr; 1072 socklen_t slen; 1073 char buf[1024]; 1074 int len, sock, r; 1075 u_int i, orig_alloc; 1076 uid_t euid; 1077 gid_t egid; 1078 1079 for (i = 0, orig_alloc = sockets_alloc; i < orig_alloc; i++) 1080 switch (sockets[i].type) { 1081 case AUTH_UNUSED: 1082 break; 1083 case AUTH_SOCKET: 1084 if (FD_ISSET(sockets[i].fd, readset)) { 1085 slen = sizeof(sunaddr); 1086 sock = accept(sockets[i].fd, 1087 (struct sockaddr *)&sunaddr, &slen); 1088 if (sock < 0) { 1089 error("accept from AUTH_SOCKET: %s", 1090 strerror(errno)); 1091 break; 1092 } 1093 if (getpeereid(sock, &euid, &egid) < 0) { 1094 error("getpeereid %d failed: %s", 1095 sock, strerror(errno)); 1096 close(sock); 1097 break; 1098 } 1099 if ((euid != 0) && (getuid() != euid)) { 1100 error("uid mismatch: " 1101 "peer euid %u != uid %u", 1102 (u_int) euid, (u_int) getuid()); 1103 close(sock); 1104 break; 1105 } 1106 new_socket(AUTH_CONNECTION, sock); 1107 } 1108 break; 1109 case AUTH_CONNECTION: 1110 if (sshbuf_len(sockets[i].output) > 0 && 1111 FD_ISSET(sockets[i].fd, writeset)) { 1112 len = write(sockets[i].fd, 1113 sshbuf_ptr(sockets[i].output), 1114 sshbuf_len(sockets[i].output)); 1115 if (len == -1 && (errno == EAGAIN || 1116 errno == EWOULDBLOCK || 1117 errno == EINTR)) 1118 continue; 1119 if (len <= 0) { 1120 close_socket(&sockets[i]); 1121 break; 1122 } 1123 if ((r = sshbuf_consume(sockets[i].output, 1124 len)) != 0) 1125 fatal("%s: buffer error: %s", 1126 __func__, ssh_err(r)); 1127 } 1128 if (FD_ISSET(sockets[i].fd, readset)) { 1129 len = read(sockets[i].fd, buf, sizeof(buf)); 1130 if (len == -1 && (errno == EAGAIN || 1131 errno == EWOULDBLOCK || 1132 errno == EINTR)) 1133 continue; 1134 if (len <= 0) { 1135 close_socket(&sockets[i]); 1136 break; 1137 } 1138 if ((r = sshbuf_put(sockets[i].input, 1139 buf, len)) != 0) 1140 fatal("%s: buffer error: %s", 1141 __func__, ssh_err(r)); 1142 explicit_bzero(buf, sizeof(buf)); 1143 process_message(&sockets[i]); 1144 } 1145 break; 1146 default: 1147 fatal("Unknown type %d", sockets[i].type); 1148 } 1149} 1150 1151static void 1152cleanup_socket(void) 1153{ 1154 if (cleanup_pid != 0 && getpid() != cleanup_pid) 1155 return; 1156 debug("%s: cleanup", __func__); 1157 if (socket_name[0]) 1158 unlink(socket_name); 1159 if (socket_dir[0]) 1160 rmdir(socket_dir); 1161} 1162 1163void 1164cleanup_exit(int i) 1165{ 1166 cleanup_socket(); 1167 _exit(i); 1168} 1169 1170/*ARGSUSED*/ 1171static void 1172cleanup_handler(int sig) 1173{ 1174 cleanup_socket(); 1175#ifdef ENABLE_PKCS11 1176 pkcs11_terminate(); 1177#endif 1178 _exit(2); 1179} 1180 1181static void 1182check_parent_exists(void) 1183{ 1184 /* 1185 * If our parent has exited then getppid() will return (pid_t)1, 1186 * so testing for that should be safe. 1187 */ 1188 if (parent_pid != -1 && getppid() != parent_pid) { 1189 /* printf("Parent has died - Authentication agent exiting.\n"); */ 1190 cleanup_socket(); 1191 _exit(2); 1192 } 1193} 1194 1195static void 1196usage(void) 1197{ 1198 fprintf(stderr, 1199 "usage: ssh-agent [-c | -s] [-Ddx] [-a bind_address] [-E fingerprint_hash]\n" 1200 " [-t life] [command [arg ...]]\n" 1201 " ssh-agent [-c | -s] -k\n"); 1202 fprintf(stderr, " -x Exit when the last client disconnects.\n"); 1203 exit(1); 1204} 1205 1206int 1207main(int ac, char **av) 1208{ 1209 int c_flag = 0, d_flag = 0, D_flag = 0, k_flag = 0, s_flag = 0; 1210 int sock, fd, ch, result, saved_errno; 1211 u_int nalloc; 1212 char *shell, *format, *pidstr, *agentsocket = NULL; 1213 fd_set *readsetp = NULL, *writesetp = NULL; 1214#ifdef HAVE_SETRLIMIT 1215 struct rlimit rlim; 1216#endif 1217 extern int optind; 1218 extern char *optarg; 1219 pid_t pid; 1220 char pidstrbuf[1 + 3 * sizeof pid]; 1221 struct timeval *tvp = NULL; 1222 size_t len; 1223 mode_t prev_mask; 1224 1225 ssh_malloc_init(); /* must be called before any mallocs */ 1226 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1227 sanitise_stdfd(); 1228 1229 /* drop */ 1230 setegid(getgid()); 1231 setgid(getgid()); 1232 setuid(geteuid()); 1233 1234 platform_disable_tracing(0); /* strict=no */ 1235 1236#ifdef WITH_OPENSSL 1237 OpenSSL_add_all_algorithms(); 1238#endif 1239 1240 __progname = ssh_get_progname(av[0]); 1241 seed_rng(); 1242 1243 while ((ch = getopt(ac, av, "cDdksE:a:t:x")) != -1) { 1244 switch (ch) { 1245 case 'E': 1246 fingerprint_hash = ssh_digest_alg_by_name(optarg); 1247 if (fingerprint_hash == -1) 1248 fatal("Invalid hash algorithm \"%s\"", optarg); 1249 break; 1250 case 'c': 1251 if (s_flag) 1252 usage(); 1253 c_flag++; 1254 break; 1255 case 'k': 1256 k_flag++; 1257 break; 1258 case 's': 1259 if (c_flag) 1260 usage(); 1261 s_flag++; 1262 break; 1263 case 'd': 1264 if (d_flag || D_flag) 1265 usage(); 1266 d_flag++; 1267 break; 1268 case 'D': 1269 if (d_flag || D_flag) 1270 usage(); 1271 D_flag++; 1272 break; 1273 case 'a': 1274 agentsocket = optarg; 1275 break; 1276 case 't': 1277 if ((lifetime = convtime(optarg)) == -1) { 1278 fprintf(stderr, "Invalid lifetime\n"); 1279 usage(); 1280 } 1281 break; 1282 case 'x': 1283 xcount = 0; 1284 break; 1285 default: 1286 usage(); 1287 } 1288 } 1289 ac -= optind; 1290 av += optind; 1291 1292 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag || D_flag)) 1293 usage(); 1294 1295 if (ac == 0 && !c_flag && !s_flag) { 1296 shell = getenv("SHELL"); 1297 if (shell != NULL && (len = strlen(shell)) > 2 && 1298 strncmp(shell + len - 3, "csh", 3) == 0) 1299 c_flag = 1; 1300 } 1301 if (k_flag) { 1302 const char *errstr = NULL; 1303 1304 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1305 if (pidstr == NULL) { 1306 fprintf(stderr, "%s not set, cannot kill agent\n", 1307 SSH_AGENTPID_ENV_NAME); 1308 exit(1); 1309 } 1310 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr); 1311 if (errstr) { 1312 fprintf(stderr, 1313 "%s=\"%s\", which is not a good PID: %s\n", 1314 SSH_AGENTPID_ENV_NAME, pidstr, errstr); 1315 exit(1); 1316 } 1317 if (kill(pid, SIGTERM) == -1) { 1318 perror("kill"); 1319 exit(1); 1320 } 1321 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 1322 printf(format, SSH_AUTHSOCKET_ENV_NAME); 1323 printf(format, SSH_AGENTPID_ENV_NAME); 1324 printf("echo Agent pid %ld killed;\n", (long)pid); 1325 exit(0); 1326 } 1327 parent_pid = getpid(); 1328 1329 if (agentsocket == NULL) { 1330 /* Create private directory for agent socket */ 1331 mktemp_proto(socket_dir, sizeof(socket_dir)); 1332 if (mkdtemp(socket_dir) == NULL) { 1333 perror("mkdtemp: private socket dir"); 1334 exit(1); 1335 } 1336 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1337 (long)parent_pid); 1338 } else { 1339 /* Try to use specified agent socket */ 1340 socket_dir[0] = '\0'; 1341 strlcpy(socket_name, agentsocket, sizeof socket_name); 1342 } 1343 1344 /* 1345 * Create socket early so it will exist before command gets run from 1346 * the parent. 1347 */ 1348 prev_mask = umask(0177); 1349 sock = unix_listener(socket_name, SSH_LISTEN_BACKLOG, 0); 1350 if (sock < 0) { 1351 /* XXX - unix_listener() calls error() not perror() */ 1352 *socket_name = '\0'; /* Don't unlink any existing file */ 1353 cleanup_exit(1); 1354 } 1355 umask(prev_mask); 1356 1357 /* 1358 * Fork, and have the parent execute the command, if any, or present 1359 * the socket data. The child continues as the authentication agent. 1360 */ 1361 if (D_flag || d_flag) { 1362 log_init(__progname, 1363 d_flag ? SYSLOG_LEVEL_DEBUG3 : SYSLOG_LEVEL_INFO, 1364 SYSLOG_FACILITY_AUTH, 1); 1365 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1366 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1367 SSH_AUTHSOCKET_ENV_NAME); 1368 printf("echo Agent pid %ld;\n", (long)parent_pid); 1369 fflush(stdout); 1370 goto skip; 1371 } 1372 pid = fork(); 1373 if (pid == -1) { 1374 perror("fork"); 1375 cleanup_exit(1); 1376 } 1377 if (pid != 0) { /* Parent - execute the given command. */ 1378 close(sock); 1379 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1380 if (ac == 0) { 1381 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1382 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1383 SSH_AUTHSOCKET_ENV_NAME); 1384 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 1385 SSH_AGENTPID_ENV_NAME); 1386 printf("echo Agent pid %ld;\n", (long)pid); 1387 exit(0); 1388 } 1389 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1390 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1391 perror("setenv"); 1392 exit(1); 1393 } 1394 execvp(av[0], av); 1395 perror(av[0]); 1396 exit(1); 1397 } 1398 /* child */ 1399 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1400 1401 if (setsid() == -1) { 1402 error("setsid: %s", strerror(errno)); 1403 cleanup_exit(1); 1404 } 1405 1406 (void)chdir("/"); 1407 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1408 /* XXX might close listen socket */ 1409 (void)dup2(fd, STDIN_FILENO); 1410 (void)dup2(fd, STDOUT_FILENO); 1411 (void)dup2(fd, STDERR_FILENO); 1412 if (fd > 2) 1413 close(fd); 1414 } 1415 1416#ifdef HAVE_SETRLIMIT 1417 /* deny core dumps, since memory contains unencrypted private keys */ 1418 rlim.rlim_cur = rlim.rlim_max = 0; 1419 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 1420 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1421 cleanup_exit(1); 1422 } 1423#endif 1424 1425skip: 1426 1427 cleanup_pid = getpid(); 1428 1429#ifdef ENABLE_PKCS11 1430 pkcs11_init(0); 1431#endif 1432 new_socket(AUTH_SOCKET, sock); 1433 if (ac > 0) 1434 parent_alive_interval = 10; 1435 idtab_init(); 1436 signal(SIGPIPE, SIG_IGN); 1437 signal(SIGINT, (d_flag | D_flag) ? cleanup_handler : SIG_IGN); 1438 signal(SIGHUP, cleanup_handler); 1439 signal(SIGTERM, cleanup_handler); 1440 nalloc = 0; 1441 1442 if (pledge("stdio cpath unix id proc exec", NULL) == -1) 1443 fatal("%s: pledge: %s", __progname, strerror(errno)); 1444 platform_pledge_agent(); 1445 1446 while (1) { 1447 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp); 1448 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp); 1449 saved_errno = errno; 1450 if (parent_alive_interval != 0) 1451 check_parent_exists(); 1452 (void) reaper(); /* remove expired keys */ 1453 if (result < 0) { 1454 if (saved_errno == EINTR) 1455 continue; 1456 fatal("select: %s", strerror(saved_errno)); 1457 } else if (result > 0) 1458 after_select(readsetp, writesetp); 1459 } 1460 /* NOTREACHED */ 1461} 1462