ssh-agent.c revision 296781
1/* $OpenBSD: ssh-agent.c,v 1.212 2016/02/15 09:47:49 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: stable/10/crypto/openssh/ssh-agent.c 296781 2016-03-12 23:53:20Z 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 92#if defined(HAVE_SYS_PRCTL_H) 93#include <sys/prctl.h> /* For prctl() and PR_SET_DUMPABLE */ 94#endif 95 96typedef enum { 97 AUTH_UNUSED, 98 AUTH_SOCKET, 99 AUTH_CONNECTION 100} sock_type; 101 102typedef struct { 103 int fd; 104 sock_type type; 105 struct sshbuf *input; 106 struct sshbuf *output; 107 struct sshbuf *request; 108} SocketEntry; 109 110u_int sockets_alloc = 0; 111SocketEntry *sockets = NULL; 112 113typedef 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 122typedef struct { 123 int nentries; 124 TAILQ_HEAD(idqueue, identity) idlist; 125} Idtab; 126 127/* private key table, one per protocol version */ 128Idtab idtable[3]; 129 130int max_fd = 0; 131 132/* pid of shell == parent of agent */ 133pid_t parent_pid = -1; 134time_t parent_alive_interval = 0; 135 136/* pid of process for which cleanup_socket is applicable */ 137pid_t cleanup_pid = 0; 138 139/* pathname and directory for AUTH_SOCKET */ 140char socket_name[PATH_MAX]; 141char socket_dir[PATH_MAX]; 142 143/* locking */ 144#define LOCK_SIZE 32 145#define LOCK_SALT_SIZE 16 146#define LOCK_ROUNDS 1 147int locked = 0; 148char lock_passwd[LOCK_SIZE]; 149char lock_salt[LOCK_SALT_SIZE]; 150 151extern char *__progname; 152 153/* Default lifetime in seconds (0 == forever) */ 154static long lifetime = 0; 155 156static 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 */ 166static int xcount = 1; 167 168static void 169close_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 188static void 189idtab_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 */ 200static Idtab * 201idtab_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 208static void 209free_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 */ 218static Identity * 219lookup_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 */ 232static int 233confirm_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 248static void 249send_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' */ 260static void 261process_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 */ 311static void 312process_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 391static char * 392agent_decode_alg(struct sshkey *key, u_int flags) 393{ 394 if (key->type == KEY_RSA) { 395 if (flags & SSH_AGENT_RSA_SHA2_256) 396 return "rsa-sha2-256"; 397 else if (flags & SSH_AGENT_RSA_SHA2_512) 398 return "rsa-sha2-512"; 399 } 400 return NULL; 401} 402 403/* ssh2 only */ 404static void 405process_sign_request2(SocketEntry *e) 406{ 407 u_char *blob, *data, *signature = NULL; 408 size_t blen, dlen, slen = 0; 409 u_int compat = 0, flags; 410 int r, ok = -1; 411 struct sshbuf *msg; 412 struct sshkey *key; 413 struct identity *id; 414 415 if ((msg = sshbuf_new()) == NULL) 416 fatal("%s: sshbuf_new failed", __func__); 417 if ((r = sshbuf_get_string(e->request, &blob, &blen)) != 0 || 418 (r = sshbuf_get_string(e->request, &data, &dlen)) != 0 || 419 (r = sshbuf_get_u32(e->request, &flags)) != 0) 420 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 421 if (flags & SSH_AGENT_OLD_SIGNATURE) 422 compat = SSH_BUG_SIGBLOB; 423 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) { 424 error("%s: cannot parse key blob: %s", __func__, ssh_err(r)); 425 goto send; 426 } 427 if ((id = lookup_identity(key, 2)) == NULL) { 428 verbose("%s: %s key not found", __func__, sshkey_type(key)); 429 goto send; 430 } 431 if (id->confirm && confirm_key(id) != 0) { 432 verbose("%s: user refused key", __func__); 433 goto send; 434 } 435 if ((r = sshkey_sign(id->key, &signature, &slen, 436 data, dlen, agent_decode_alg(key, flags), compat)) != 0) { 437 error("%s: sshkey_sign: %s", __func__, ssh_err(r)); 438 goto send; 439 } 440 /* Success */ 441 ok = 0; 442 send: 443 sshkey_free(key); 444 if (ok == 0) { 445 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 || 446 (r = sshbuf_put_string(msg, signature, slen)) != 0) 447 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 448 } else if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0) 449 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 450 451 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 452 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 453 454 sshbuf_free(msg); 455 free(data); 456 free(blob); 457 free(signature); 458} 459 460/* shared */ 461static void 462process_remove_identity(SocketEntry *e, int version) 463{ 464 size_t blen; 465 int r, success = 0; 466 struct sshkey *key = NULL; 467 u_char *blob; 468#ifdef WITH_SSH1 469 u_int bits; 470#endif /* WITH_SSH1 */ 471 472 switch (version) { 473#ifdef WITH_SSH1 474 case 1: 475 if ((key = sshkey_new(KEY_RSA1)) == NULL) { 476 error("%s: sshkey_new failed", __func__); 477 return; 478 } 479 if ((r = sshbuf_get_u32(e->request, &bits)) != 0 || 480 (r = sshbuf_get_bignum1(e->request, key->rsa->e)) != 0 || 481 (r = sshbuf_get_bignum1(e->request, key->rsa->n)) != 0) 482 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 483 484 if (bits != sshkey_size(key)) 485 logit("Warning: identity keysize mismatch: " 486 "actual %u, announced %u", 487 sshkey_size(key), bits); 488 break; 489#endif /* WITH_SSH1 */ 490 case 2: 491 if ((r = sshbuf_get_string(e->request, &blob, &blen)) != 0) 492 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 493 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) 494 error("%s: sshkey_from_blob failed: %s", 495 __func__, ssh_err(r)); 496 free(blob); 497 break; 498 } 499 if (key != NULL) { 500 Identity *id = lookup_identity(key, version); 501 if (id != NULL) { 502 /* 503 * We have this key. Free the old key. Since we 504 * don't want to leave empty slots in the middle of 505 * the array, we actually free the key there and move 506 * all the entries between the empty slot and the end 507 * of the array. 508 */ 509 Idtab *tab = idtab_lookup(version); 510 if (tab->nentries < 1) 511 fatal("process_remove_identity: " 512 "internal error: tab->nentries %d", 513 tab->nentries); 514 TAILQ_REMOVE(&tab->idlist, id, next); 515 free_identity(id); 516 tab->nentries--; 517 success = 1; 518 } 519 sshkey_free(key); 520 } 521 send_status(e, success); 522} 523 524static void 525process_remove_all_identities(SocketEntry *e, int version) 526{ 527 Idtab *tab = idtab_lookup(version); 528 Identity *id; 529 530 /* Loop over all identities and clear the keys. */ 531 for (id = TAILQ_FIRST(&tab->idlist); id; 532 id = TAILQ_FIRST(&tab->idlist)) { 533 TAILQ_REMOVE(&tab->idlist, id, next); 534 free_identity(id); 535 } 536 537 /* Mark that there are no identities. */ 538 tab->nentries = 0; 539 540 /* Send success. */ 541 send_status(e, 1); 542} 543 544/* removes expired keys and returns number of seconds until the next expiry */ 545static time_t 546reaper(void) 547{ 548 time_t deadline = 0, now = monotime(); 549 Identity *id, *nxt; 550 int version; 551 Idtab *tab; 552 553 for (version = 1; version < 3; version++) { 554 tab = idtab_lookup(version); 555 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 556 nxt = TAILQ_NEXT(id, next); 557 if (id->death == 0) 558 continue; 559 if (now >= id->death) { 560 debug("expiring key '%s'", id->comment); 561 TAILQ_REMOVE(&tab->idlist, id, next); 562 free_identity(id); 563 tab->nentries--; 564 } else 565 deadline = (deadline == 0) ? id->death : 566 MIN(deadline, id->death); 567 } 568 } 569 if (deadline == 0 || deadline <= now) 570 return 0; 571 else 572 return (deadline - now); 573} 574 575/* 576 * XXX this and the corresponding serialisation function probably belongs 577 * in key.c 578 */ 579#ifdef WITH_SSH1 580static int 581agent_decode_rsa1(struct sshbuf *m, struct sshkey **kp) 582{ 583 struct sshkey *k = NULL; 584 int r = SSH_ERR_INTERNAL_ERROR; 585 586 *kp = NULL; 587 if ((k = sshkey_new_private(KEY_RSA1)) == NULL) 588 return SSH_ERR_ALLOC_FAIL; 589 590 if ((r = sshbuf_get_u32(m, NULL)) != 0 || /* ignored */ 591 (r = sshbuf_get_bignum1(m, k->rsa->n)) != 0 || 592 (r = sshbuf_get_bignum1(m, k->rsa->e)) != 0 || 593 (r = sshbuf_get_bignum1(m, k->rsa->d)) != 0 || 594 (r = sshbuf_get_bignum1(m, k->rsa->iqmp)) != 0 || 595 /* SSH1 and SSL have p and q swapped */ 596 (r = sshbuf_get_bignum1(m, k->rsa->q)) != 0 || /* p */ 597 (r = sshbuf_get_bignum1(m, k->rsa->p)) != 0) /* q */ 598 goto out; 599 600 /* Generate additional parameters */ 601 if ((r = rsa_generate_additional_parameters(k->rsa)) != 0) 602 goto out; 603 /* enable blinding */ 604 if (RSA_blinding_on(k->rsa, NULL) != 1) { 605 r = SSH_ERR_LIBCRYPTO_ERROR; 606 goto out; 607 } 608 609 r = 0; /* success */ 610 out: 611 if (r == 0) 612 *kp = k; 613 else 614 sshkey_free(k); 615 return r; 616} 617#endif /* WITH_SSH1 */ 618 619static void 620process_add_identity(SocketEntry *e, int version) 621{ 622 Idtab *tab = idtab_lookup(version); 623 Identity *id; 624 int success = 0, confirm = 0; 625 u_int seconds; 626 char *comment = NULL; 627 time_t death = 0; 628 struct sshkey *k = NULL; 629 u_char ctype; 630 int r = SSH_ERR_INTERNAL_ERROR; 631 632 switch (version) { 633#ifdef WITH_SSH1 634 case 1: 635 r = agent_decode_rsa1(e->request, &k); 636 break; 637#endif /* WITH_SSH1 */ 638 case 2: 639 r = sshkey_private_deserialize(e->request, &k); 640 break; 641 } 642 if (r != 0 || k == NULL || 643 (r = sshbuf_get_cstring(e->request, &comment, NULL)) != 0) { 644 error("%s: decode private key: %s", __func__, ssh_err(r)); 645 goto err; 646 } 647 648 while (sshbuf_len(e->request)) { 649 if ((r = sshbuf_get_u8(e->request, &ctype)) != 0) { 650 error("%s: buffer error: %s", __func__, ssh_err(r)); 651 goto err; 652 } 653 switch (ctype) { 654 case SSH_AGENT_CONSTRAIN_LIFETIME: 655 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) { 656 error("%s: bad lifetime constraint: %s", 657 __func__, ssh_err(r)); 658 goto err; 659 } 660 death = monotime() + seconds; 661 break; 662 case SSH_AGENT_CONSTRAIN_CONFIRM: 663 confirm = 1; 664 break; 665 default: 666 error("%s: Unknown constraint %d", __func__, ctype); 667 err: 668 sshbuf_reset(e->request); 669 free(comment); 670 sshkey_free(k); 671 goto send; 672 } 673 } 674 675 success = 1; 676 if (lifetime && !death) 677 death = monotime() + lifetime; 678 if ((id = lookup_identity(k, version)) == NULL) { 679 id = xcalloc(1, sizeof(Identity)); 680 id->key = k; 681 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 682 /* Increment the number of identities. */ 683 tab->nentries++; 684 } else { 685 sshkey_free(k); 686 free(id->comment); 687 } 688 id->comment = comment; 689 id->death = death; 690 id->confirm = confirm; 691send: 692 send_status(e, success); 693} 694 695/* XXX todo: encrypt sensitive data with passphrase */ 696static void 697process_lock_agent(SocketEntry *e, int lock) 698{ 699 int r, success = 0, delay; 700 char *passwd, passwdhash[LOCK_SIZE]; 701 static u_int fail_count = 0; 702 size_t pwlen; 703 704 if ((r = sshbuf_get_cstring(e->request, &passwd, &pwlen)) != 0) 705 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 706 if (pwlen == 0) { 707 debug("empty password not supported"); 708 } else if (locked && !lock) { 709 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 710 passwdhash, sizeof(passwdhash), LOCK_ROUNDS) < 0) 711 fatal("bcrypt_pbkdf"); 712 if (timingsafe_bcmp(passwdhash, lock_passwd, LOCK_SIZE) == 0) { 713 debug("agent unlocked"); 714 locked = 0; 715 fail_count = 0; 716 explicit_bzero(lock_passwd, sizeof(lock_passwd)); 717 success = 1; 718 } else { 719 /* delay in 0.1s increments up to 10s */ 720 if (fail_count < 100) 721 fail_count++; 722 delay = 100000 * fail_count; 723 debug("unlock failed, delaying %0.1lf seconds", 724 (double)delay/1000000); 725 usleep(delay); 726 } 727 explicit_bzero(passwdhash, sizeof(passwdhash)); 728 } else if (!locked && lock) { 729 debug("agent locked"); 730 locked = 1; 731 arc4random_buf(lock_salt, sizeof(lock_salt)); 732 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 733 lock_passwd, sizeof(lock_passwd), LOCK_ROUNDS) < 0) 734 fatal("bcrypt_pbkdf"); 735 success = 1; 736 } 737 explicit_bzero(passwd, pwlen); 738 free(passwd); 739 send_status(e, success); 740} 741 742static void 743no_identities(SocketEntry *e, u_int type) 744{ 745 struct sshbuf *msg; 746 int r; 747 748 if ((msg = sshbuf_new()) == NULL) 749 fatal("%s: sshbuf_new failed", __func__); 750 if ((r = sshbuf_put_u8(msg, 751 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ? 752 SSH_AGENT_RSA_IDENTITIES_ANSWER : 753 SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 754 (r = sshbuf_put_u32(msg, 0)) != 0 || 755 (r = sshbuf_put_stringb(e->output, msg)) != 0) 756 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 757 sshbuf_free(msg); 758} 759 760#ifdef ENABLE_PKCS11 761static void 762process_add_smartcard_key(SocketEntry *e) 763{ 764 char *provider = NULL, *pin; 765 int r, i, version, count = 0, success = 0, confirm = 0; 766 u_int seconds; 767 time_t death = 0; 768 u_char type; 769 struct sshkey **keys = NULL, *k; 770 Identity *id; 771 Idtab *tab; 772 773 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 774 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) 775 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 776 777 while (sshbuf_len(e->request)) { 778 if ((r = sshbuf_get_u8(e->request, &type)) != 0) 779 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 780 switch (type) { 781 case SSH_AGENT_CONSTRAIN_LIFETIME: 782 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) 783 fatal("%s: buffer error: %s", 784 __func__, ssh_err(r)); 785 death = monotime() + seconds; 786 break; 787 case SSH_AGENT_CONSTRAIN_CONFIRM: 788 confirm = 1; 789 break; 790 default: 791 error("process_add_smartcard_key: " 792 "Unknown constraint type %d", type); 793 goto send; 794 } 795 } 796 if (lifetime && !death) 797 death = monotime() + lifetime; 798 799 count = pkcs11_add_provider(provider, pin, &keys); 800 for (i = 0; i < count; i++) { 801 k = keys[i]; 802 version = k->type == KEY_RSA1 ? 1 : 2; 803 tab = idtab_lookup(version); 804 if (lookup_identity(k, version) == NULL) { 805 id = xcalloc(1, sizeof(Identity)); 806 id->key = k; 807 id->provider = xstrdup(provider); 808 id->comment = xstrdup(provider); /* XXX */ 809 id->death = death; 810 id->confirm = confirm; 811 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 812 tab->nentries++; 813 success = 1; 814 } else { 815 sshkey_free(k); 816 } 817 keys[i] = NULL; 818 } 819send: 820 free(pin); 821 free(provider); 822 free(keys); 823 send_status(e, success); 824} 825 826static void 827process_remove_smartcard_key(SocketEntry *e) 828{ 829 char *provider = NULL, *pin = NULL; 830 int r, version, success = 0; 831 Identity *id, *nxt; 832 Idtab *tab; 833 834 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 835 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) 836 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 837 free(pin); 838 839 for (version = 1; version < 3; version++) { 840 tab = idtab_lookup(version); 841 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 842 nxt = TAILQ_NEXT(id, next); 843 /* Skip file--based keys */ 844 if (id->provider == NULL) 845 continue; 846 if (!strcmp(provider, id->provider)) { 847 TAILQ_REMOVE(&tab->idlist, id, next); 848 free_identity(id); 849 tab->nentries--; 850 } 851 } 852 } 853 if (pkcs11_del_provider(provider) == 0) 854 success = 1; 855 else 856 error("process_remove_smartcard_key:" 857 " pkcs11_del_provider failed"); 858 free(provider); 859 send_status(e, success); 860} 861#endif /* ENABLE_PKCS11 */ 862 863/* dispatch incoming messages */ 864 865static void 866process_message(SocketEntry *e) 867{ 868 u_int msg_len; 869 u_char type; 870 const u_char *cp; 871 int r; 872 873 if (sshbuf_len(e->input) < 5) 874 return; /* Incomplete message. */ 875 cp = sshbuf_ptr(e->input); 876 msg_len = PEEK_U32(cp); 877 if (msg_len > 256 * 1024) { 878 close_socket(e); 879 return; 880 } 881 if (sshbuf_len(e->input) < msg_len + 4) 882 return; 883 884 /* move the current input to e->request */ 885 sshbuf_reset(e->request); 886 if ((r = sshbuf_get_stringb(e->input, e->request)) != 0 || 887 (r = sshbuf_get_u8(e->request, &type)) != 0) 888 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 889 890 /* check wheter agent is locked */ 891 if (locked && type != SSH_AGENTC_UNLOCK) { 892 sshbuf_reset(e->request); 893 switch (type) { 894 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 895 case SSH2_AGENTC_REQUEST_IDENTITIES: 896 /* send empty lists */ 897 no_identities(e, type); 898 break; 899 default: 900 /* send a fail message for all other request types */ 901 send_status(e, 0); 902 } 903 return; 904 } 905 906 debug("type %d", type); 907 switch (type) { 908 case SSH_AGENTC_LOCK: 909 case SSH_AGENTC_UNLOCK: 910 process_lock_agent(e, type == SSH_AGENTC_LOCK); 911 break; 912#ifdef WITH_SSH1 913 /* ssh1 */ 914 case SSH_AGENTC_RSA_CHALLENGE: 915 process_authentication_challenge1(e); 916 break; 917 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 918 process_request_identities(e, 1); 919 break; 920 case SSH_AGENTC_ADD_RSA_IDENTITY: 921 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 922 process_add_identity(e, 1); 923 break; 924 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 925 process_remove_identity(e, 1); 926 break; 927#endif 928 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 929 process_remove_all_identities(e, 1); /* safe for !WITH_SSH1 */ 930 break; 931 /* ssh2 */ 932 case SSH2_AGENTC_SIGN_REQUEST: 933 process_sign_request2(e); 934 break; 935 case SSH2_AGENTC_REQUEST_IDENTITIES: 936 process_request_identities(e, 2); 937 break; 938 case SSH2_AGENTC_ADD_IDENTITY: 939 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 940 process_add_identity(e, 2); 941 break; 942 case SSH2_AGENTC_REMOVE_IDENTITY: 943 process_remove_identity(e, 2); 944 break; 945 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 946 process_remove_all_identities(e, 2); 947 break; 948#ifdef ENABLE_PKCS11 949 case SSH_AGENTC_ADD_SMARTCARD_KEY: 950 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 951 process_add_smartcard_key(e); 952 break; 953 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 954 process_remove_smartcard_key(e); 955 break; 956#endif /* ENABLE_PKCS11 */ 957 default: 958 /* Unknown message. Respond with failure. */ 959 error("Unknown message %d", type); 960 sshbuf_reset(e->request); 961 send_status(e, 0); 962 break; 963 } 964} 965 966static void 967new_socket(sock_type type, int fd) 968{ 969 u_int i, old_alloc, new_alloc; 970 971 if (type == AUTH_CONNECTION) { 972 debug("xcount %d -> %d", xcount, xcount + 1); 973 ++xcount; 974 } 975 set_nonblock(fd); 976 977 if (fd > max_fd) 978 max_fd = fd; 979 980 for (i = 0; i < sockets_alloc; i++) 981 if (sockets[i].type == AUTH_UNUSED) { 982 sockets[i].fd = fd; 983 if ((sockets[i].input = sshbuf_new()) == NULL) 984 fatal("%s: sshbuf_new failed", __func__); 985 if ((sockets[i].output = sshbuf_new()) == NULL) 986 fatal("%s: sshbuf_new failed", __func__); 987 if ((sockets[i].request = sshbuf_new()) == NULL) 988 fatal("%s: sshbuf_new failed", __func__); 989 sockets[i].type = type; 990 return; 991 } 992 old_alloc = sockets_alloc; 993 new_alloc = sockets_alloc + 10; 994 sockets = xreallocarray(sockets, new_alloc, sizeof(sockets[0])); 995 for (i = old_alloc; i < new_alloc; i++) 996 sockets[i].type = AUTH_UNUSED; 997 sockets_alloc = new_alloc; 998 sockets[old_alloc].fd = fd; 999 if ((sockets[old_alloc].input = sshbuf_new()) == NULL) 1000 fatal("%s: sshbuf_new failed", __func__); 1001 if ((sockets[old_alloc].output = sshbuf_new()) == NULL) 1002 fatal("%s: sshbuf_new failed", __func__); 1003 if ((sockets[old_alloc].request = sshbuf_new()) == NULL) 1004 fatal("%s: sshbuf_new failed", __func__); 1005 sockets[old_alloc].type = type; 1006} 1007 1008static int 1009prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp, 1010 struct timeval **tvpp) 1011{ 1012 u_int i, sz; 1013 int n = 0; 1014 static struct timeval tv; 1015 time_t deadline; 1016 1017 for (i = 0; i < sockets_alloc; i++) { 1018 switch (sockets[i].type) { 1019 case AUTH_SOCKET: 1020 case AUTH_CONNECTION: 1021 n = MAX(n, sockets[i].fd); 1022 break; 1023 case AUTH_UNUSED: 1024 break; 1025 default: 1026 fatal("Unknown socket type %d", sockets[i].type); 1027 break; 1028 } 1029 } 1030 1031 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 1032 if (*fdrp == NULL || sz > *nallocp) { 1033 free(*fdrp); 1034 free(*fdwp); 1035 *fdrp = xmalloc(sz); 1036 *fdwp = xmalloc(sz); 1037 *nallocp = sz; 1038 } 1039 if (n < *fdl) 1040 debug("XXX shrink: %d < %d", n, *fdl); 1041 *fdl = n; 1042 memset(*fdrp, 0, sz); 1043 memset(*fdwp, 0, sz); 1044 1045 for (i = 0; i < sockets_alloc; i++) { 1046 switch (sockets[i].type) { 1047 case AUTH_SOCKET: 1048 case AUTH_CONNECTION: 1049 FD_SET(sockets[i].fd, *fdrp); 1050 if (sshbuf_len(sockets[i].output) > 0) 1051 FD_SET(sockets[i].fd, *fdwp); 1052 break; 1053 default: 1054 break; 1055 } 1056 } 1057 deadline = reaper(); 1058 if (parent_alive_interval != 0) 1059 deadline = (deadline == 0) ? parent_alive_interval : 1060 MIN(deadline, parent_alive_interval); 1061 if (deadline == 0) { 1062 *tvpp = NULL; 1063 } else { 1064 tv.tv_sec = deadline; 1065 tv.tv_usec = 0; 1066 *tvpp = &tv; 1067 } 1068 return (1); 1069} 1070 1071static void 1072after_select(fd_set *readset, fd_set *writeset) 1073{ 1074 struct sockaddr_un sunaddr; 1075 socklen_t slen; 1076 char buf[1024]; 1077 int len, sock, r; 1078 u_int i, orig_alloc; 1079 uid_t euid; 1080 gid_t egid; 1081 1082 for (i = 0, orig_alloc = sockets_alloc; i < orig_alloc; i++) 1083 switch (sockets[i].type) { 1084 case AUTH_UNUSED: 1085 break; 1086 case AUTH_SOCKET: 1087 if (FD_ISSET(sockets[i].fd, readset)) { 1088 slen = sizeof(sunaddr); 1089 sock = accept(sockets[i].fd, 1090 (struct sockaddr *)&sunaddr, &slen); 1091 if (sock < 0) { 1092 error("accept from AUTH_SOCKET: %s", 1093 strerror(errno)); 1094 break; 1095 } 1096 if (getpeereid(sock, &euid, &egid) < 0) { 1097 error("getpeereid %d failed: %s", 1098 sock, strerror(errno)); 1099 close(sock); 1100 break; 1101 } 1102 if ((euid != 0) && (getuid() != euid)) { 1103 error("uid mismatch: " 1104 "peer euid %u != uid %u", 1105 (u_int) euid, (u_int) getuid()); 1106 close(sock); 1107 break; 1108 } 1109 new_socket(AUTH_CONNECTION, sock); 1110 } 1111 break; 1112 case AUTH_CONNECTION: 1113 if (sshbuf_len(sockets[i].output) > 0 && 1114 FD_ISSET(sockets[i].fd, writeset)) { 1115 len = write(sockets[i].fd, 1116 sshbuf_ptr(sockets[i].output), 1117 sshbuf_len(sockets[i].output)); 1118 if (len == -1 && (errno == EAGAIN || 1119 errno == EWOULDBLOCK || 1120 errno == EINTR)) 1121 continue; 1122 if (len <= 0) { 1123 close_socket(&sockets[i]); 1124 break; 1125 } 1126 if ((r = sshbuf_consume(sockets[i].output, 1127 len)) != 0) 1128 fatal("%s: buffer error: %s", 1129 __func__, ssh_err(r)); 1130 } 1131 if (FD_ISSET(sockets[i].fd, readset)) { 1132 len = read(sockets[i].fd, buf, sizeof(buf)); 1133 if (len == -1 && (errno == EAGAIN || 1134 errno == EWOULDBLOCK || 1135 errno == EINTR)) 1136 continue; 1137 if (len <= 0) { 1138 close_socket(&sockets[i]); 1139 break; 1140 } 1141 if ((r = sshbuf_put(sockets[i].input, 1142 buf, len)) != 0) 1143 fatal("%s: buffer error: %s", 1144 __func__, ssh_err(r)); 1145 explicit_bzero(buf, sizeof(buf)); 1146 process_message(&sockets[i]); 1147 } 1148 break; 1149 default: 1150 fatal("Unknown type %d", sockets[i].type); 1151 } 1152} 1153 1154static void 1155cleanup_socket(void) 1156{ 1157 if (cleanup_pid != 0 && getpid() != cleanup_pid) 1158 return; 1159 debug("%s: cleanup", __func__); 1160 if (socket_name[0]) 1161 unlink(socket_name); 1162 if (socket_dir[0]) 1163 rmdir(socket_dir); 1164} 1165 1166void 1167cleanup_exit(int i) 1168{ 1169 cleanup_socket(); 1170 _exit(i); 1171} 1172 1173/*ARGSUSED*/ 1174static void 1175cleanup_handler(int sig) 1176{ 1177 cleanup_socket(); 1178#ifdef ENABLE_PKCS11 1179 pkcs11_terminate(); 1180#endif 1181 _exit(2); 1182} 1183 1184static void 1185check_parent_exists(void) 1186{ 1187 /* 1188 * If our parent has exited then getppid() will return (pid_t)1, 1189 * so testing for that should be safe. 1190 */ 1191 if (parent_pid != -1 && getppid() != parent_pid) { 1192 /* printf("Parent has died - Authentication agent exiting.\n"); */ 1193 cleanup_socket(); 1194 _exit(2); 1195 } 1196} 1197 1198static void 1199usage(void) 1200{ 1201 fprintf(stderr, 1202 "usage: ssh-agent [-c | -s] [-Dd] [-a bind_address] [-E fingerprint_hash]\n" 1203 " [-t life] [command [arg ...]]\n" 1204 " ssh-agent [-c | -s] -k\n"); 1205 fprintf(stderr, " -x Exit when the last client disconnects.\n"); 1206 exit(1); 1207} 1208 1209int 1210main(int ac, char **av) 1211{ 1212 int c_flag = 0, d_flag = 0, D_flag = 0, k_flag = 0, s_flag = 0; 1213 int sock, fd, ch, result, saved_errno; 1214 u_int nalloc; 1215 char *shell, *format, *pidstr, *agentsocket = NULL; 1216 fd_set *readsetp = NULL, *writesetp = NULL; 1217#ifdef HAVE_SETRLIMIT 1218 struct rlimit rlim; 1219#endif 1220 extern int optind; 1221 extern char *optarg; 1222 pid_t pid; 1223 char pidstrbuf[1 + 3 * sizeof pid]; 1224 struct timeval *tvp = NULL; 1225 size_t len; 1226 mode_t prev_mask; 1227 1228 ssh_malloc_init(); /* must be called before any mallocs */ 1229 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1230 sanitise_stdfd(); 1231 1232 /* drop */ 1233 setegid(getgid()); 1234 setgid(getgid()); 1235 setuid(geteuid()); 1236 1237#if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE) 1238 /* Disable ptrace on Linux without sgid bit */ 1239 prctl(PR_SET_DUMPABLE, 0); 1240#endif 1241 1242#ifdef WITH_OPENSSL 1243 OpenSSL_add_all_algorithms(); 1244#endif 1245 1246 __progname = ssh_get_progname(av[0]); 1247 seed_rng(); 1248 1249 while ((ch = getopt(ac, av, "cDdksE:a:t:x")) != -1) { 1250 switch (ch) { 1251 case 'E': 1252 fingerprint_hash = ssh_digest_alg_by_name(optarg); 1253 if (fingerprint_hash == -1) 1254 fatal("Invalid hash algorithm \"%s\"", optarg); 1255 break; 1256 case 'c': 1257 if (s_flag) 1258 usage(); 1259 c_flag++; 1260 break; 1261 case 'k': 1262 k_flag++; 1263 break; 1264 case 's': 1265 if (c_flag) 1266 usage(); 1267 s_flag++; 1268 break; 1269 case 'd': 1270 if (d_flag || D_flag) 1271 usage(); 1272 d_flag++; 1273 break; 1274 case 'D': 1275 if (d_flag || D_flag) 1276 usage(); 1277 D_flag++; 1278 break; 1279 case 'a': 1280 agentsocket = optarg; 1281 break; 1282 case 't': 1283 if ((lifetime = convtime(optarg)) == -1) { 1284 fprintf(stderr, "Invalid lifetime\n"); 1285 usage(); 1286 } 1287 break; 1288 case 'x': 1289 xcount = 0; 1290 break; 1291 default: 1292 usage(); 1293 } 1294 } 1295 ac -= optind; 1296 av += optind; 1297 1298 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag || D_flag)) 1299 usage(); 1300 1301 if (ac == 0 && !c_flag && !s_flag) { 1302 shell = getenv("SHELL"); 1303 if (shell != NULL && (len = strlen(shell)) > 2 && 1304 strncmp(shell + len - 3, "csh", 3) == 0) 1305 c_flag = 1; 1306 } 1307 if (k_flag) { 1308 const char *errstr = NULL; 1309 1310 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1311 if (pidstr == NULL) { 1312 fprintf(stderr, "%s not set, cannot kill agent\n", 1313 SSH_AGENTPID_ENV_NAME); 1314 exit(1); 1315 } 1316 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr); 1317 if (errstr) { 1318 fprintf(stderr, 1319 "%s=\"%s\", which is not a good PID: %s\n", 1320 SSH_AGENTPID_ENV_NAME, pidstr, errstr); 1321 exit(1); 1322 } 1323 if (kill(pid, SIGTERM) == -1) { 1324 perror("kill"); 1325 exit(1); 1326 } 1327 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 1328 printf(format, SSH_AUTHSOCKET_ENV_NAME); 1329 printf(format, SSH_AGENTPID_ENV_NAME); 1330 printf("echo Agent pid %ld killed;\n", (long)pid); 1331 exit(0); 1332 } 1333 parent_pid = getpid(); 1334 1335 if (agentsocket == NULL) { 1336 /* Create private directory for agent socket */ 1337 mktemp_proto(socket_dir, sizeof(socket_dir)); 1338 if (mkdtemp(socket_dir) == NULL) { 1339 perror("mkdtemp: private socket dir"); 1340 exit(1); 1341 } 1342 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1343 (long)parent_pid); 1344 } else { 1345 /* Try to use specified agent socket */ 1346 socket_dir[0] = '\0'; 1347 strlcpy(socket_name, agentsocket, sizeof socket_name); 1348 } 1349 1350 /* 1351 * Create socket early so it will exist before command gets run from 1352 * the parent. 1353 */ 1354 prev_mask = umask(0177); 1355 sock = unix_listener(socket_name, SSH_LISTEN_BACKLOG, 0); 1356 if (sock < 0) { 1357 /* XXX - unix_listener() calls error() not perror() */ 1358 *socket_name = '\0'; /* Don't unlink any existing file */ 1359 cleanup_exit(1); 1360 } 1361 umask(prev_mask); 1362 1363 /* 1364 * Fork, and have the parent execute the command, if any, or present 1365 * the socket data. The child continues as the authentication agent. 1366 */ 1367 if (D_flag || d_flag) { 1368 log_init(__progname, 1369 d_flag ? SYSLOG_LEVEL_DEBUG3 : SYSLOG_LEVEL_INFO, 1370 SYSLOG_FACILITY_AUTH, 1); 1371 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1372 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1373 SSH_AUTHSOCKET_ENV_NAME); 1374 printf("echo Agent pid %ld;\n", (long)parent_pid); 1375 fflush(stdout); 1376 goto skip; 1377 } 1378 pid = fork(); 1379 if (pid == -1) { 1380 perror("fork"); 1381 cleanup_exit(1); 1382 } 1383 if (pid != 0) { /* Parent - execute the given command. */ 1384 close(sock); 1385 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1386 if (ac == 0) { 1387 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1388 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1389 SSH_AUTHSOCKET_ENV_NAME); 1390 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 1391 SSH_AGENTPID_ENV_NAME); 1392 printf("echo Agent pid %ld;\n", (long)pid); 1393 exit(0); 1394 } 1395 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1396 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1397 perror("setenv"); 1398 exit(1); 1399 } 1400 execvp(av[0], av); 1401 perror(av[0]); 1402 exit(1); 1403 } 1404 /* child */ 1405 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1406 1407 if (setsid() == -1) { 1408 error("setsid: %s", strerror(errno)); 1409 cleanup_exit(1); 1410 } 1411 1412 (void)chdir("/"); 1413 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1414 /* XXX might close listen socket */ 1415 (void)dup2(fd, STDIN_FILENO); 1416 (void)dup2(fd, STDOUT_FILENO); 1417 (void)dup2(fd, STDERR_FILENO); 1418 if (fd > 2) 1419 close(fd); 1420 } 1421 1422#ifdef HAVE_SETRLIMIT 1423 /* deny core dumps, since memory contains unencrypted private keys */ 1424 rlim.rlim_cur = rlim.rlim_max = 0; 1425 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 1426 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1427 cleanup_exit(1); 1428 } 1429#endif 1430 1431skip: 1432 1433 cleanup_pid = getpid(); 1434 1435#ifdef ENABLE_PKCS11 1436 pkcs11_init(0); 1437#endif 1438 new_socket(AUTH_SOCKET, sock); 1439 if (ac > 0) 1440 parent_alive_interval = 10; 1441 idtab_init(); 1442 signal(SIGPIPE, SIG_IGN); 1443 signal(SIGINT, (d_flag | D_flag) ? cleanup_handler : SIG_IGN); 1444 signal(SIGHUP, cleanup_handler); 1445 signal(SIGTERM, cleanup_handler); 1446 nalloc = 0; 1447 1448 if (pledge("stdio cpath unix id proc exec", NULL) == -1) 1449 fatal("%s: pledge: %s", __progname, strerror(errno)); 1450 platform_pledge_agent(); 1451 1452 while (1) { 1453 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp); 1454 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp); 1455 saved_errno = errno; 1456 if (parent_alive_interval != 0) 1457 check_parent_exists(); 1458 (void) reaper(); /* remove expired keys */ 1459 if (result < 0) { 1460 if (saved_errno == EINTR) 1461 continue; 1462 fatal("select: %s", strerror(saved_errno)); 1463 } else if (result > 0) 1464 after_select(readsetp, writesetp); 1465 } 1466 /* NOTREACHED */ 1467} 1468