1 /* $OpenBSD: ssh-agent.c,v 1.216 2017/01/04 02:21:43 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 <sys/types.h> 38 #include <sys/time.h> 39 #include <sys/queue.h> 40 #include <sys/resource.h> 41 #include <sys/socket.h> 42 #include <sys/stat.h> 43 #include <sys/un.h> 44 45 #ifdef WITH_OPENSSL 46 #include <openssl/evp.h> 47 #endif 48 49 #include <errno.h> 50 #include <fcntl.h> 51 #include <paths.h> 52 #include <signal.h> 53 #include <stdlib.h> 54 #include <stdio.h> 55 #include <string.h> 56 #include <limits.h> 57 #include <time.h> 58 #include <unistd.h> 59 #include <util.h> 60 61 #include "xmalloc.h" 62 #include "ssh.h" 63 #include "rsa.h" 64 #include "sshbuf.h" 65 #include "sshkey.h" 66 #include "authfd.h" 67 #include "compat.h" 68 #include "log.h" 69 #include "misc.h" 70 #include "digest.h" 71 #include "ssherr.h" 72 #include "match.h" 73 74 #ifdef ENABLE_PKCS11 75 #include "ssh-pkcs11.h" 76 #endif 77 78 #ifndef DEFAULT_PKCS11_WHITELIST 79 # define DEFAULT_PKCS11_WHITELIST "/usr/lib*/*,/usr/local/lib*/*" 80 #endif 81 82 typedef enum { 83 AUTH_UNUSED, 84 AUTH_SOCKET, 85 AUTH_CONNECTION 86 } sock_type; 87 88 typedef struct { 89 int fd; 90 sock_type type; 91 struct sshbuf *input; 92 struct sshbuf *output; 93 struct sshbuf *request; 94 } SocketEntry; 95 96 u_int sockets_alloc = 0; 97 SocketEntry *sockets = NULL; 98 99 typedef struct identity { 100 TAILQ_ENTRY(identity) next; 101 struct sshkey *key; 102 char *comment; 103 char *provider; 104 time_t death; 105 u_int confirm; 106 } Identity; 107 108 typedef struct { 109 int nentries; 110 TAILQ_HEAD(idqueue, identity) idlist; 111 } Idtab; 112 113 /* private key table, one per protocol version */ 114 Idtab idtable[3]; 115 116 int max_fd = 0; 117 118 /* pid of shell == parent of agent */ 119 pid_t parent_pid = -1; 120 time_t parent_alive_interval = 0; 121 122 /* pid of process for which cleanup_socket is applicable */ 123 pid_t cleanup_pid = 0; 124 125 /* pathname and directory for AUTH_SOCKET */ 126 char socket_name[PATH_MAX]; 127 char socket_dir[PATH_MAX]; 128 129 /* PKCS#11 path whitelist */ 130 static char *pkcs11_whitelist; 131 132 /* locking */ 133 #define LOCK_SIZE 32 134 #define LOCK_SALT_SIZE 16 135 #define LOCK_ROUNDS 1 136 int locked = 0; 137 u_char lock_pwhash[LOCK_SIZE]; 138 u_char lock_salt[LOCK_SALT_SIZE]; 139 140 extern char *__progname; 141 142 /* Default lifetime in seconds (0 == forever) */ 143 static long lifetime = 0; 144 145 static int fingerprint_hash = SSH_FP_HASH_DEFAULT; 146 147 static void 148 close_socket(SocketEntry *e) 149 { 150 close(e->fd); 151 e->fd = -1; 152 e->type = AUTH_UNUSED; 153 sshbuf_free(e->input); 154 sshbuf_free(e->output); 155 sshbuf_free(e->request); 156 } 157 158 static void 159 idtab_init(void) 160 { 161 int i; 162 163 for (i = 0; i <=2; i++) { 164 TAILQ_INIT(&idtable[i].idlist); 165 idtable[i].nentries = 0; 166 } 167 } 168 169 /* return private key table for requested protocol version */ 170 static Idtab * 171 idtab_lookup(int version) 172 { 173 if (version < 1 || version > 2) 174 fatal("internal error, bad protocol version %d", version); 175 return &idtable[version]; 176 } 177 178 static void 179 free_identity(Identity *id) 180 { 181 sshkey_free(id->key); 182 free(id->provider); 183 free(id->comment); 184 free(id); 185 } 186 187 /* return matching private key for given public key */ 188 static Identity * 189 lookup_identity(struct sshkey *key, int version) 190 { 191 Identity *id; 192 193 Idtab *tab = idtab_lookup(version); 194 TAILQ_FOREACH(id, &tab->idlist, next) { 195 if (sshkey_equal(key, id->key)) 196 return (id); 197 } 198 return (NULL); 199 } 200 201 /* Check confirmation of keysign request */ 202 static int 203 confirm_key(Identity *id) 204 { 205 char *p; 206 int ret = -1; 207 208 p = sshkey_fingerprint(id->key, fingerprint_hash, SSH_FP_DEFAULT); 209 if (p != NULL && 210 ask_permission("Allow use of key %s?\nKey fingerprint %s.", 211 id->comment, p)) 212 ret = 0; 213 free(p); 214 215 return (ret); 216 } 217 218 static void 219 send_status(SocketEntry *e, int success) 220 { 221 int r; 222 223 if ((r = sshbuf_put_u32(e->output, 1)) != 0 || 224 (r = sshbuf_put_u8(e->output, success ? 225 SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0) 226 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 227 } 228 229 /* send list of supported public keys to 'client' */ 230 static void 231 process_request_identities(SocketEntry *e, int version) 232 { 233 Idtab *tab = idtab_lookup(version); 234 Identity *id; 235 struct sshbuf *msg; 236 int r; 237 238 if ((msg = sshbuf_new()) == NULL) 239 fatal("%s: sshbuf_new failed", __func__); 240 if ((r = sshbuf_put_u8(msg, (version == 1) ? 241 SSH_AGENT_RSA_IDENTITIES_ANSWER : 242 SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 243 (r = sshbuf_put_u32(msg, tab->nentries)) != 0) 244 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 245 TAILQ_FOREACH(id, &tab->idlist, next) { 246 if (id->key->type == KEY_RSA1) { 247 #ifdef WITH_SSH1 248 if ((r = sshbuf_put_u32(msg, 249 BN_num_bits(id->key->rsa->n))) != 0 || 250 (r = sshbuf_put_bignum1(msg, 251 id->key->rsa->e)) != 0 || 252 (r = sshbuf_put_bignum1(msg, 253 id->key->rsa->n)) != 0) 254 fatal("%s: buffer error: %s", 255 __func__, ssh_err(r)); 256 #endif 257 } else { 258 u_char *blob; 259 size_t blen; 260 261 if ((r = sshkey_to_blob(id->key, &blob, &blen)) != 0) { 262 error("%s: sshkey_to_blob: %s", __func__, 263 ssh_err(r)); 264 continue; 265 } 266 if ((r = sshbuf_put_string(msg, blob, blen)) != 0) 267 fatal("%s: buffer error: %s", 268 __func__, ssh_err(r)); 269 free(blob); 270 } 271 if ((r = sshbuf_put_cstring(msg, id->comment)) != 0) 272 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 273 } 274 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 275 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 276 sshbuf_free(msg); 277 } 278 279 #ifdef WITH_SSH1 280 /* ssh1 only */ 281 static void 282 process_authentication_challenge1(SocketEntry *e) 283 { 284 u_char buf[32], mdbuf[16], session_id[16]; 285 u_int response_type; 286 BIGNUM *challenge; 287 Identity *id; 288 int r, len; 289 struct sshbuf *msg; 290 struct ssh_digest_ctx *md; 291 struct sshkey *key; 292 293 if ((msg = sshbuf_new()) == NULL) 294 fatal("%s: sshbuf_new failed", __func__); 295 if ((key = sshkey_new(KEY_RSA1)) == NULL) 296 fatal("%s: sshkey_new failed", __func__); 297 if ((challenge = BN_new()) == NULL) 298 fatal("%s: BN_new failed", __func__); 299 300 if ((r = sshbuf_get_u32(e->request, NULL)) != 0 || /* ignored */ 301 (r = sshbuf_get_bignum1(e->request, key->rsa->e)) != 0 || 302 (r = sshbuf_get_bignum1(e->request, key->rsa->n)) != 0 || 303 (r = sshbuf_get_bignum1(e->request, challenge))) 304 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 305 306 /* Only protocol 1.1 is supported */ 307 if (sshbuf_len(e->request) == 0) 308 goto failure; 309 if ((r = sshbuf_get(e->request, session_id, sizeof(session_id))) != 0 || 310 (r = sshbuf_get_u32(e->request, &response_type)) != 0) 311 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 312 if (response_type != 1) 313 goto failure; 314 315 id = lookup_identity(key, 1); 316 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) { 317 struct sshkey *private = id->key; 318 /* Decrypt the challenge using the private key. */ 319 if ((r = rsa_private_decrypt(challenge, challenge, 320 private->rsa) != 0)) { 321 fatal("%s: rsa_public_encrypt: %s", __func__, 322 ssh_err(r)); 323 goto failure; /* XXX ? */ 324 } 325 326 /* The response is MD5 of decrypted challenge plus session id */ 327 len = BN_num_bytes(challenge); 328 if (len <= 0 || len > 32) { 329 logit("%s: bad challenge length %d", __func__, len); 330 goto failure; 331 } 332 memset(buf, 0, 32); 333 BN_bn2bin(challenge, buf + 32 - len); 334 if ((md = ssh_digest_start(SSH_DIGEST_MD5)) == NULL || 335 ssh_digest_update(md, buf, 32) < 0 || 336 ssh_digest_update(md, session_id, 16) < 0 || 337 ssh_digest_final(md, mdbuf, sizeof(mdbuf)) < 0) 338 fatal("%s: md5 failed", __func__); 339 ssh_digest_free(md); 340 341 /* Send the response. */ 342 if ((r = sshbuf_put_u8(msg, SSH_AGENT_RSA_RESPONSE)) != 0 || 343 (r = sshbuf_put(msg, mdbuf, sizeof(mdbuf))) != 0) 344 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 345 goto send; 346 } 347 348 failure: 349 /* Unknown identity or protocol error. Send failure. */ 350 if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0) 351 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 352 send: 353 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 354 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 355 sshkey_free(key); 356 BN_clear_free(challenge); 357 sshbuf_free(msg); 358 } 359 #endif 360 361 static char * 362 agent_decode_alg(struct sshkey *key, u_int flags) 363 { 364 if (key->type == KEY_RSA) { 365 if (flags & SSH_AGENT_RSA_SHA2_256) 366 return "rsa-sha2-256"; 367 else if (flags & SSH_AGENT_RSA_SHA2_512) 368 return "rsa-sha2-512"; 369 } 370 return NULL; 371 } 372 373 /* ssh2 only */ 374 static void 375 process_sign_request2(SocketEntry *e) 376 { 377 u_char *blob, *data, *signature = NULL; 378 size_t blen, dlen, slen = 0; 379 u_int compat = 0, flags; 380 int r, ok = -1; 381 struct sshbuf *msg; 382 struct sshkey *key; 383 struct identity *id; 384 385 if ((msg = sshbuf_new()) == NULL) 386 fatal("%s: sshbuf_new failed", __func__); 387 if ((r = sshbuf_get_string(e->request, &blob, &blen)) != 0 || 388 (r = sshbuf_get_string(e->request, &data, &dlen)) != 0 || 389 (r = sshbuf_get_u32(e->request, &flags)) != 0) 390 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 391 if (flags & SSH_AGENT_OLD_SIGNATURE) 392 compat = SSH_BUG_SIGBLOB; 393 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) { 394 error("%s: cannot parse key blob: %s", __func__, ssh_err(r)); 395 goto send; 396 } 397 if ((id = lookup_identity(key, 2)) == NULL) { 398 verbose("%s: %s key not found", __func__, sshkey_type(key)); 399 goto send; 400 } 401 if (id->confirm && confirm_key(id) != 0) { 402 verbose("%s: user refused key", __func__); 403 goto send; 404 } 405 if ((r = sshkey_sign(id->key, &signature, &slen, 406 data, dlen, agent_decode_alg(key, flags), compat)) != 0) { 407 error("%s: sshkey_sign: %s", __func__, ssh_err(r)); 408 goto send; 409 } 410 /* Success */ 411 ok = 0; 412 send: 413 sshkey_free(key); 414 if (ok == 0) { 415 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 || 416 (r = sshbuf_put_string(msg, signature, slen)) != 0) 417 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 418 } else if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0) 419 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 420 421 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 422 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 423 424 sshbuf_free(msg); 425 free(data); 426 free(blob); 427 free(signature); 428 } 429 430 /* shared */ 431 static void 432 process_remove_identity(SocketEntry *e, int version) 433 { 434 size_t blen; 435 int r, success = 0; 436 struct sshkey *key = NULL; 437 u_char *blob; 438 #ifdef WITH_SSH1 439 u_int bits; 440 #endif /* WITH_SSH1 */ 441 442 switch (version) { 443 #ifdef WITH_SSH1 444 case 1: 445 if ((key = sshkey_new(KEY_RSA1)) == NULL) { 446 error("%s: sshkey_new failed", __func__); 447 return; 448 } 449 if ((r = sshbuf_get_u32(e->request, &bits)) != 0 || 450 (r = sshbuf_get_bignum1(e->request, key->rsa->e)) != 0 || 451 (r = sshbuf_get_bignum1(e->request, key->rsa->n)) != 0) 452 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 453 454 if (bits != sshkey_size(key)) 455 logit("Warning: identity keysize mismatch: " 456 "actual %u, announced %u", 457 sshkey_size(key), bits); 458 break; 459 #endif /* WITH_SSH1 */ 460 case 2: 461 if ((r = sshbuf_get_string(e->request, &blob, &blen)) != 0) 462 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 463 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) 464 error("%s: sshkey_from_blob failed: %s", 465 __func__, ssh_err(r)); 466 free(blob); 467 break; 468 } 469 if (key != NULL) { 470 Identity *id = lookup_identity(key, version); 471 if (id != NULL) { 472 /* 473 * We have this key. Free the old key. Since we 474 * don't want to leave empty slots in the middle of 475 * the array, we actually free the key there and move 476 * all the entries between the empty slot and the end 477 * of the array. 478 */ 479 Idtab *tab = idtab_lookup(version); 480 if (tab->nentries < 1) 481 fatal("process_remove_identity: " 482 "internal error: tab->nentries %d", 483 tab->nentries); 484 TAILQ_REMOVE(&tab->idlist, id, next); 485 free_identity(id); 486 tab->nentries--; 487 success = 1; 488 } 489 sshkey_free(key); 490 } 491 send_status(e, success); 492 } 493 494 static void 495 process_remove_all_identities(SocketEntry *e, int version) 496 { 497 Idtab *tab = idtab_lookup(version); 498 Identity *id; 499 500 /* Loop over all identities and clear the keys. */ 501 for (id = TAILQ_FIRST(&tab->idlist); id; 502 id = TAILQ_FIRST(&tab->idlist)) { 503 TAILQ_REMOVE(&tab->idlist, id, next); 504 free_identity(id); 505 } 506 507 /* Mark that there are no identities. */ 508 tab->nentries = 0; 509 510 /* Send success. */ 511 send_status(e, 1); 512 } 513 514 /* removes expired keys and returns number of seconds until the next expiry */ 515 static time_t 516 reaper(void) 517 { 518 time_t deadline = 0, now = monotime(); 519 Identity *id, *nxt; 520 int version; 521 Idtab *tab; 522 523 for (version = 1; version < 3; version++) { 524 tab = idtab_lookup(version); 525 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 526 nxt = TAILQ_NEXT(id, next); 527 if (id->death == 0) 528 continue; 529 if (now >= id->death) { 530 debug("expiring key '%s'", id->comment); 531 TAILQ_REMOVE(&tab->idlist, id, next); 532 free_identity(id); 533 tab->nentries--; 534 } else 535 deadline = (deadline == 0) ? id->death : 536 MINIMUM(deadline, id->death); 537 } 538 } 539 if (deadline == 0 || deadline <= now) 540 return 0; 541 else 542 return (deadline - now); 543 } 544 545 /* 546 * XXX this and the corresponding serialisation function probably belongs 547 * in key.c 548 */ 549 #ifdef WITH_SSH1 550 static int 551 agent_decode_rsa1(struct sshbuf *m, struct sshkey **kp) 552 { 553 struct sshkey *k = NULL; 554 int r = SSH_ERR_INTERNAL_ERROR; 555 556 *kp = NULL; 557 if ((k = sshkey_new_private(KEY_RSA1)) == NULL) 558 return SSH_ERR_ALLOC_FAIL; 559 560 if ((r = sshbuf_get_u32(m, NULL)) != 0 || /* ignored */ 561 (r = sshbuf_get_bignum1(m, k->rsa->n)) != 0 || 562 (r = sshbuf_get_bignum1(m, k->rsa->e)) != 0 || 563 (r = sshbuf_get_bignum1(m, k->rsa->d)) != 0 || 564 (r = sshbuf_get_bignum1(m, k->rsa->iqmp)) != 0 || 565 /* SSH1 and SSL have p and q swapped */ 566 (r = sshbuf_get_bignum1(m, k->rsa->q)) != 0 || /* p */ 567 (r = sshbuf_get_bignum1(m, k->rsa->p)) != 0) /* q */ 568 goto out; 569 570 /* Generate additional parameters */ 571 if ((r = rsa_generate_additional_parameters(k->rsa)) != 0) 572 goto out; 573 /* enable blinding */ 574 if (RSA_blinding_on(k->rsa, NULL) != 1) { 575 r = SSH_ERR_LIBCRYPTO_ERROR; 576 goto out; 577 } 578 579 r = 0; /* success */ 580 out: 581 if (r == 0) 582 *kp = k; 583 else 584 sshkey_free(k); 585 return r; 586 } 587 #endif /* WITH_SSH1 */ 588 589 static void 590 process_add_identity(SocketEntry *e, int version) 591 { 592 Idtab *tab = idtab_lookup(version); 593 Identity *id; 594 int success = 0, confirm = 0; 595 u_int seconds; 596 char *comment = NULL; 597 time_t death = 0; 598 struct sshkey *k = NULL; 599 u_char ctype; 600 int r = SSH_ERR_INTERNAL_ERROR; 601 602 switch (version) { 603 #ifdef WITH_SSH1 604 case 1: 605 r = agent_decode_rsa1(e->request, &k); 606 break; 607 #endif /* WITH_SSH1 */ 608 case 2: 609 r = sshkey_private_deserialize(e->request, &k); 610 break; 611 } 612 if (r != 0 || k == NULL || 613 (r = sshbuf_get_cstring(e->request, &comment, NULL)) != 0) { 614 error("%s: decode private key: %s", __func__, ssh_err(r)); 615 goto err; 616 } 617 618 while (sshbuf_len(e->request)) { 619 if ((r = sshbuf_get_u8(e->request, &ctype)) != 0) { 620 error("%s: buffer error: %s", __func__, ssh_err(r)); 621 goto err; 622 } 623 switch (ctype) { 624 case SSH_AGENT_CONSTRAIN_LIFETIME: 625 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) { 626 error("%s: bad lifetime constraint: %s", 627 __func__, ssh_err(r)); 628 goto err; 629 } 630 death = monotime() + seconds; 631 break; 632 case SSH_AGENT_CONSTRAIN_CONFIRM: 633 confirm = 1; 634 break; 635 default: 636 error("%s: Unknown constraint %d", __func__, ctype); 637 err: 638 sshbuf_reset(e->request); 639 free(comment); 640 sshkey_free(k); 641 goto send; 642 } 643 } 644 645 success = 1; 646 if (lifetime && !death) 647 death = monotime() + lifetime; 648 if ((id = lookup_identity(k, version)) == NULL) { 649 id = xcalloc(1, sizeof(Identity)); 650 id->key = k; 651 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 652 /* Increment the number of identities. */ 653 tab->nentries++; 654 } else { 655 sshkey_free(k); 656 free(id->comment); 657 } 658 id->comment = comment; 659 id->death = death; 660 id->confirm = confirm; 661 send: 662 send_status(e, success); 663 } 664 665 /* XXX todo: encrypt sensitive data with passphrase */ 666 static void 667 process_lock_agent(SocketEntry *e, int lock) 668 { 669 int r, success = 0, delay; 670 char *passwd; 671 u_char passwdhash[LOCK_SIZE]; 672 static u_int fail_count = 0; 673 size_t pwlen; 674 675 if ((r = sshbuf_get_cstring(e->request, &passwd, &pwlen)) != 0) 676 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 677 if (pwlen == 0) { 678 debug("empty password not supported"); 679 } else if (locked && !lock) { 680 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 681 passwdhash, sizeof(passwdhash), LOCK_ROUNDS) < 0) 682 fatal("bcrypt_pbkdf"); 683 if (timingsafe_bcmp(passwdhash, lock_pwhash, LOCK_SIZE) == 0) { 684 debug("agent unlocked"); 685 locked = 0; 686 fail_count = 0; 687 explicit_bzero(lock_pwhash, sizeof(lock_pwhash)); 688 success = 1; 689 } else { 690 /* delay in 0.1s increments up to 10s */ 691 if (fail_count < 100) 692 fail_count++; 693 delay = 100000 * fail_count; 694 debug("unlock failed, delaying %0.1lf seconds", 695 (double)delay/1000000); 696 usleep(delay); 697 } 698 explicit_bzero(passwdhash, sizeof(passwdhash)); 699 } else if (!locked && lock) { 700 debug("agent locked"); 701 locked = 1; 702 arc4random_buf(lock_salt, sizeof(lock_salt)); 703 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 704 lock_pwhash, sizeof(lock_pwhash), LOCK_ROUNDS) < 0) 705 fatal("bcrypt_pbkdf"); 706 success = 1; 707 } 708 explicit_bzero(passwd, pwlen); 709 free(passwd); 710 send_status(e, success); 711 } 712 713 static void 714 no_identities(SocketEntry *e, u_int type) 715 { 716 struct sshbuf *msg; 717 int r; 718 719 if ((msg = sshbuf_new()) == NULL) 720 fatal("%s: sshbuf_new failed", __func__); 721 if ((r = sshbuf_put_u8(msg, 722 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ? 723 SSH_AGENT_RSA_IDENTITIES_ANSWER : 724 SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 725 (r = sshbuf_put_u32(msg, 0)) != 0 || 726 (r = sshbuf_put_stringb(e->output, msg)) != 0) 727 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 728 sshbuf_free(msg); 729 } 730 731 #ifdef ENABLE_PKCS11 732 static void 733 process_add_smartcard_key(SocketEntry *e) 734 { 735 char *provider = NULL, *pin, canonical_provider[PATH_MAX]; 736 int r, i, version, count = 0, success = 0, confirm = 0; 737 u_int seconds; 738 time_t death = 0; 739 u_char type; 740 struct sshkey **keys = NULL, *k; 741 Identity *id; 742 Idtab *tab; 743 744 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 745 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) 746 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 747 748 while (sshbuf_len(e->request)) { 749 if ((r = sshbuf_get_u8(e->request, &type)) != 0) 750 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 751 switch (type) { 752 case SSH_AGENT_CONSTRAIN_LIFETIME: 753 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) 754 fatal("%s: buffer error: %s", 755 __func__, ssh_err(r)); 756 death = monotime() + seconds; 757 break; 758 case SSH_AGENT_CONSTRAIN_CONFIRM: 759 confirm = 1; 760 break; 761 default: 762 error("process_add_smartcard_key: " 763 "Unknown constraint type %d", type); 764 goto send; 765 } 766 } 767 if (realpath(provider, canonical_provider) == NULL) { 768 verbose("failed PKCS#11 add of \"%.100s\": realpath: %s", 769 provider, strerror(errno)); 770 goto send; 771 } 772 if (match_pattern_list(canonical_provider, pkcs11_whitelist, 0) != 1) { 773 verbose("refusing PKCS#11 add of \"%.100s\": " 774 "provider not whitelisted", canonical_provider); 775 goto send; 776 } 777 debug("%s: add %.100s", __func__, canonical_provider); 778 if (lifetime && !death) 779 death = monotime() + lifetime; 780 781 count = pkcs11_add_provider(canonical_provider, pin, &keys); 782 for (i = 0; i < count; i++) { 783 k = keys[i]; 784 version = k->type == KEY_RSA1 ? 1 : 2; 785 tab = idtab_lookup(version); 786 if (lookup_identity(k, version) == NULL) { 787 id = xcalloc(1, sizeof(Identity)); 788 id->key = k; 789 id->provider = xstrdup(canonical_provider); 790 id->comment = xstrdup(canonical_provider); /* XXX */ 791 id->death = death; 792 id->confirm = confirm; 793 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 794 tab->nentries++; 795 success = 1; 796 } else { 797 sshkey_free(k); 798 } 799 keys[i] = NULL; 800 } 801 send: 802 free(pin); 803 free(provider); 804 free(keys); 805 send_status(e, success); 806 } 807 808 static void 809 process_remove_smartcard_key(SocketEntry *e) 810 { 811 char *provider = NULL, *pin = NULL; 812 int r, version, success = 0; 813 Identity *id, *nxt; 814 Idtab *tab; 815 816 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 817 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) 818 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 819 free(pin); 820 821 for (version = 1; version < 3; version++) { 822 tab = idtab_lookup(version); 823 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 824 nxt = TAILQ_NEXT(id, next); 825 /* Skip file--based keys */ 826 if (id->provider == NULL) 827 continue; 828 if (!strcmp(provider, id->provider)) { 829 TAILQ_REMOVE(&tab->idlist, id, next); 830 free_identity(id); 831 tab->nentries--; 832 } 833 } 834 } 835 if (pkcs11_del_provider(provider) == 0) 836 success = 1; 837 else 838 error("process_remove_smartcard_key:" 839 " pkcs11_del_provider failed"); 840 free(provider); 841 send_status(e, success); 842 } 843 #endif /* ENABLE_PKCS11 */ 844 845 /* dispatch incoming messages */ 846 847 static void 848 process_message(SocketEntry *e) 849 { 850 u_int msg_len; 851 u_char type; 852 const u_char *cp; 853 int r; 854 855 if (sshbuf_len(e->input) < 5) 856 return; /* Incomplete message. */ 857 cp = sshbuf_ptr(e->input); 858 msg_len = PEEK_U32(cp); 859 if (msg_len > 256 * 1024) { 860 close_socket(e); 861 return; 862 } 863 if (sshbuf_len(e->input) < msg_len + 4) 864 return; 865 866 /* move the current input to e->request */ 867 sshbuf_reset(e->request); 868 if ((r = sshbuf_get_stringb(e->input, e->request)) != 0 || 869 (r = sshbuf_get_u8(e->request, &type)) != 0) 870 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 871 872 /* check wheter agent is locked */ 873 if (locked && type != SSH_AGENTC_UNLOCK) { 874 sshbuf_reset(e->request); 875 switch (type) { 876 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 877 case SSH2_AGENTC_REQUEST_IDENTITIES: 878 /* send empty lists */ 879 no_identities(e, type); 880 break; 881 default: 882 /* send a fail message for all other request types */ 883 send_status(e, 0); 884 } 885 return; 886 } 887 888 debug("type %d", type); 889 switch (type) { 890 case SSH_AGENTC_LOCK: 891 case SSH_AGENTC_UNLOCK: 892 process_lock_agent(e, type == SSH_AGENTC_LOCK); 893 break; 894 #ifdef WITH_SSH1 895 /* ssh1 */ 896 case SSH_AGENTC_RSA_CHALLENGE: 897 process_authentication_challenge1(e); 898 break; 899 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 900 process_request_identities(e, 1); 901 break; 902 case SSH_AGENTC_ADD_RSA_IDENTITY: 903 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 904 process_add_identity(e, 1); 905 break; 906 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 907 process_remove_identity(e, 1); 908 break; 909 #endif 910 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 911 process_remove_all_identities(e, 1); /* safe for !WITH_SSH1 */ 912 break; 913 /* ssh2 */ 914 case SSH2_AGENTC_SIGN_REQUEST: 915 process_sign_request2(e); 916 break; 917 case SSH2_AGENTC_REQUEST_IDENTITIES: 918 process_request_identities(e, 2); 919 break; 920 case SSH2_AGENTC_ADD_IDENTITY: 921 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 922 process_add_identity(e, 2); 923 break; 924 case SSH2_AGENTC_REMOVE_IDENTITY: 925 process_remove_identity(e, 2); 926 break; 927 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 928 process_remove_all_identities(e, 2); 929 break; 930 #ifdef ENABLE_PKCS11 931 case SSH_AGENTC_ADD_SMARTCARD_KEY: 932 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 933 process_add_smartcard_key(e); 934 break; 935 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 936 process_remove_smartcard_key(e); 937 break; 938 #endif /* ENABLE_PKCS11 */ 939 default: 940 /* Unknown message. Respond with failure. */ 941 error("Unknown message %d", type); 942 sshbuf_reset(e->request); 943 send_status(e, 0); 944 break; 945 } 946 } 947 948 static void 949 new_socket(sock_type type, int fd) 950 { 951 u_int i, old_alloc, new_alloc; 952 953 set_nonblock(fd); 954 955 if (fd > max_fd) 956 max_fd = fd; 957 958 for (i = 0; i < sockets_alloc; i++) 959 if (sockets[i].type == AUTH_UNUSED) { 960 sockets[i].fd = fd; 961 if ((sockets[i].input = sshbuf_new()) == NULL) 962 fatal("%s: sshbuf_new failed", __func__); 963 if ((sockets[i].output = sshbuf_new()) == NULL) 964 fatal("%s: sshbuf_new failed", __func__); 965 if ((sockets[i].request = sshbuf_new()) == NULL) 966 fatal("%s: sshbuf_new failed", __func__); 967 sockets[i].type = type; 968 return; 969 } 970 old_alloc = sockets_alloc; 971 new_alloc = sockets_alloc + 10; 972 sockets = xreallocarray(sockets, new_alloc, sizeof(sockets[0])); 973 for (i = old_alloc; i < new_alloc; i++) 974 sockets[i].type = AUTH_UNUSED; 975 sockets_alloc = new_alloc; 976 sockets[old_alloc].fd = fd; 977 if ((sockets[old_alloc].input = sshbuf_new()) == NULL) 978 fatal("%s: sshbuf_new failed", __func__); 979 if ((sockets[old_alloc].output = sshbuf_new()) == NULL) 980 fatal("%s: sshbuf_new failed", __func__); 981 if ((sockets[old_alloc].request = sshbuf_new()) == NULL) 982 fatal("%s: sshbuf_new failed", __func__); 983 sockets[old_alloc].type = type; 984 } 985 986 static int 987 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp, 988 struct timeval **tvpp) 989 { 990 u_int i, sz; 991 int n = 0; 992 static struct timeval tv; 993 time_t deadline; 994 995 for (i = 0; i < sockets_alloc; i++) { 996 switch (sockets[i].type) { 997 case AUTH_SOCKET: 998 case AUTH_CONNECTION: 999 n = MAXIMUM(n, sockets[i].fd); 1000 break; 1001 case AUTH_UNUSED: 1002 break; 1003 default: 1004 fatal("Unknown socket type %d", sockets[i].type); 1005 break; 1006 } 1007 } 1008 1009 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 1010 if (*fdrp == NULL || sz > *nallocp) { 1011 free(*fdrp); 1012 free(*fdwp); 1013 *fdrp = xmalloc(sz); 1014 *fdwp = xmalloc(sz); 1015 *nallocp = sz; 1016 } 1017 if (n < *fdl) 1018 debug("XXX shrink: %d < %d", n, *fdl); 1019 *fdl = n; 1020 memset(*fdrp, 0, sz); 1021 memset(*fdwp, 0, sz); 1022 1023 for (i = 0; i < sockets_alloc; i++) { 1024 switch (sockets[i].type) { 1025 case AUTH_SOCKET: 1026 case AUTH_CONNECTION: 1027 FD_SET(sockets[i].fd, *fdrp); 1028 if (sshbuf_len(sockets[i].output) > 0) 1029 FD_SET(sockets[i].fd, *fdwp); 1030 break; 1031 default: 1032 break; 1033 } 1034 } 1035 deadline = reaper(); 1036 if (parent_alive_interval != 0) 1037 deadline = (deadline == 0) ? parent_alive_interval : 1038 MINIMUM(deadline, parent_alive_interval); 1039 if (deadline == 0) { 1040 *tvpp = NULL; 1041 } else { 1042 tv.tv_sec = deadline; 1043 tv.tv_usec = 0; 1044 *tvpp = &tv; 1045 } 1046 return (1); 1047 } 1048 1049 static void 1050 after_select(fd_set *readset, fd_set *writeset) 1051 { 1052 struct sockaddr_un sunaddr; 1053 socklen_t slen; 1054 char buf[1024]; 1055 int len, sock, r; 1056 u_int i, orig_alloc; 1057 uid_t euid; 1058 gid_t egid; 1059 1060 for (i = 0, orig_alloc = sockets_alloc; i < orig_alloc; i++) 1061 switch (sockets[i].type) { 1062 case AUTH_UNUSED: 1063 break; 1064 case AUTH_SOCKET: 1065 if (FD_ISSET(sockets[i].fd, readset)) { 1066 slen = sizeof(sunaddr); 1067 sock = accept(sockets[i].fd, 1068 (struct sockaddr *)&sunaddr, &slen); 1069 if (sock < 0) { 1070 error("accept from AUTH_SOCKET: %s", 1071 strerror(errno)); 1072 break; 1073 } 1074 if (getpeereid(sock, &euid, &egid) < 0) { 1075 error("getpeereid %d failed: %s", 1076 sock, strerror(errno)); 1077 close(sock); 1078 break; 1079 } 1080 if ((euid != 0) && (getuid() != euid)) { 1081 error("uid mismatch: " 1082 "peer euid %u != uid %u", 1083 (u_int) euid, (u_int) getuid()); 1084 close(sock); 1085 break; 1086 } 1087 new_socket(AUTH_CONNECTION, sock); 1088 } 1089 break; 1090 case AUTH_CONNECTION: 1091 if (sshbuf_len(sockets[i].output) > 0 && 1092 FD_ISSET(sockets[i].fd, writeset)) { 1093 len = write(sockets[i].fd, 1094 sshbuf_ptr(sockets[i].output), 1095 sshbuf_len(sockets[i].output)); 1096 if (len == -1 && (errno == EAGAIN || 1097 errno == EINTR)) 1098 continue; 1099 if (len <= 0) { 1100 close_socket(&sockets[i]); 1101 break; 1102 } 1103 if ((r = sshbuf_consume(sockets[i].output, 1104 len)) != 0) 1105 fatal("%s: buffer error: %s", 1106 __func__, ssh_err(r)); 1107 } 1108 if (FD_ISSET(sockets[i].fd, readset)) { 1109 len = read(sockets[i].fd, buf, sizeof(buf)); 1110 if (len == -1 && (errno == EAGAIN || 1111 errno == EINTR)) 1112 continue; 1113 if (len <= 0) { 1114 close_socket(&sockets[i]); 1115 break; 1116 } 1117 if ((r = sshbuf_put(sockets[i].input, 1118 buf, len)) != 0) 1119 fatal("%s: buffer error: %s", 1120 __func__, ssh_err(r)); 1121 explicit_bzero(buf, sizeof(buf)); 1122 process_message(&sockets[i]); 1123 } 1124 break; 1125 default: 1126 fatal("Unknown type %d", sockets[i].type); 1127 } 1128 } 1129 1130 static void 1131 cleanup_socket(void) 1132 { 1133 if (cleanup_pid != 0 && getpid() != cleanup_pid) 1134 return; 1135 debug("%s: cleanup", __func__); 1136 if (socket_name[0]) 1137 unlink(socket_name); 1138 if (socket_dir[0]) 1139 rmdir(socket_dir); 1140 } 1141 1142 void 1143 cleanup_exit(int i) 1144 { 1145 cleanup_socket(); 1146 _exit(i); 1147 } 1148 1149 /*ARGSUSED*/ 1150 static void 1151 cleanup_handler(int sig) 1152 { 1153 cleanup_socket(); 1154 #ifdef ENABLE_PKCS11 1155 pkcs11_terminate(); 1156 #endif 1157 _exit(2); 1158 } 1159 1160 static void 1161 check_parent_exists(void) 1162 { 1163 /* 1164 * If our parent has exited then getppid() will return (pid_t)1, 1165 * so testing for that should be safe. 1166 */ 1167 if (parent_pid != -1 && getppid() != parent_pid) { 1168 /* printf("Parent has died - Authentication agent exiting.\n"); */ 1169 cleanup_socket(); 1170 _exit(2); 1171 } 1172 } 1173 1174 static void 1175 usage(void) 1176 { 1177 fprintf(stderr, 1178 "usage: ssh-agent [-c | -s] [-Dd] [-a bind_address] [-E fingerprint_hash]\n" 1179 " [-P pkcs11_whitelist] [-t life] [command [arg ...]]\n" 1180 " ssh-agent [-c | -s] -k\n"); 1181 exit(1); 1182 } 1183 1184 int 1185 main(int ac, char **av) 1186 { 1187 int c_flag = 0, d_flag = 0, D_flag = 0, k_flag = 0, s_flag = 0; 1188 int sock, fd, ch, result, saved_errno; 1189 u_int nalloc; 1190 char *shell, *format, *pidstr, *agentsocket = NULL; 1191 fd_set *readsetp = NULL, *writesetp = NULL; 1192 struct rlimit rlim; 1193 extern int optind; 1194 extern char *optarg; 1195 pid_t pid; 1196 char pidstrbuf[1 + 3 * sizeof pid]; 1197 struct timeval *tvp = NULL; 1198 size_t len; 1199 mode_t prev_mask; 1200 1201 ssh_malloc_init(); /* must be called before any mallocs */ 1202 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1203 sanitise_stdfd(); 1204 1205 /* drop */ 1206 setegid(getgid()); 1207 setgid(getgid()); 1208 1209 #ifdef WITH_OPENSSL 1210 OpenSSL_add_all_algorithms(); 1211 #endif 1212 1213 while ((ch = getopt(ac, av, "cDdksE:a:P:t:")) != -1) { 1214 switch (ch) { 1215 case 'E': 1216 fingerprint_hash = ssh_digest_alg_by_name(optarg); 1217 if (fingerprint_hash == -1) 1218 fatal("Invalid hash algorithm \"%s\"", optarg); 1219 break; 1220 case 'c': 1221 if (s_flag) 1222 usage(); 1223 c_flag++; 1224 break; 1225 case 'k': 1226 k_flag++; 1227 break; 1228 case 'P': 1229 if (pkcs11_whitelist != NULL) 1230 fatal("-P option already specified"); 1231 pkcs11_whitelist = xstrdup(optarg); 1232 break; 1233 case 's': 1234 if (c_flag) 1235 usage(); 1236 s_flag++; 1237 break; 1238 case 'd': 1239 if (d_flag || D_flag) 1240 usage(); 1241 d_flag++; 1242 break; 1243 case 'D': 1244 if (d_flag || D_flag) 1245 usage(); 1246 D_flag++; 1247 break; 1248 case 'a': 1249 agentsocket = optarg; 1250 break; 1251 case 't': 1252 if ((lifetime = convtime(optarg)) == -1) { 1253 fprintf(stderr, "Invalid lifetime\n"); 1254 usage(); 1255 } 1256 break; 1257 default: 1258 usage(); 1259 } 1260 } 1261 ac -= optind; 1262 av += optind; 1263 1264 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag || D_flag)) 1265 usage(); 1266 1267 if (pkcs11_whitelist == NULL) 1268 pkcs11_whitelist = xstrdup(DEFAULT_PKCS11_WHITELIST); 1269 1270 if (ac == 0 && !c_flag && !s_flag) { 1271 shell = getenv("SHELL"); 1272 if (shell != NULL && (len = strlen(shell)) > 2 && 1273 strncmp(shell + len - 3, "csh", 3) == 0) 1274 c_flag = 1; 1275 } 1276 if (k_flag) { 1277 const char *errstr = NULL; 1278 1279 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1280 if (pidstr == NULL) { 1281 fprintf(stderr, "%s not set, cannot kill agent\n", 1282 SSH_AGENTPID_ENV_NAME); 1283 exit(1); 1284 } 1285 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr); 1286 if (errstr) { 1287 fprintf(stderr, 1288 "%s=\"%s\", which is not a good PID: %s\n", 1289 SSH_AGENTPID_ENV_NAME, pidstr, errstr); 1290 exit(1); 1291 } 1292 if (kill(pid, SIGTERM) == -1) { 1293 perror("kill"); 1294 exit(1); 1295 } 1296 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 1297 printf(format, SSH_AUTHSOCKET_ENV_NAME); 1298 printf(format, SSH_AGENTPID_ENV_NAME); 1299 printf("echo Agent pid %ld killed;\n", (long)pid); 1300 exit(0); 1301 } 1302 parent_pid = getpid(); 1303 1304 if (agentsocket == NULL) { 1305 /* Create private directory for agent socket */ 1306 mktemp_proto(socket_dir, sizeof(socket_dir)); 1307 if (mkdtemp(socket_dir) == NULL) { 1308 perror("mkdtemp: private socket dir"); 1309 exit(1); 1310 } 1311 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1312 (long)parent_pid); 1313 } else { 1314 /* Try to use specified agent socket */ 1315 socket_dir[0] = '\0'; 1316 strlcpy(socket_name, agentsocket, sizeof socket_name); 1317 } 1318 1319 /* 1320 * Create socket early so it will exist before command gets run from 1321 * the parent. 1322 */ 1323 prev_mask = umask(0177); 1324 sock = unix_listener(socket_name, SSH_LISTEN_BACKLOG, 0); 1325 if (sock < 0) { 1326 /* XXX - unix_listener() calls error() not perror() */ 1327 *socket_name = '\0'; /* Don't unlink any existing file */ 1328 cleanup_exit(1); 1329 } 1330 umask(prev_mask); 1331 1332 /* 1333 * Fork, and have the parent execute the command, if any, or present 1334 * the socket data. The child continues as the authentication agent. 1335 */ 1336 if (D_flag || d_flag) { 1337 log_init(__progname, 1338 d_flag ? SYSLOG_LEVEL_DEBUG3 : SYSLOG_LEVEL_INFO, 1339 SYSLOG_FACILITY_AUTH, 1); 1340 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1341 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1342 SSH_AUTHSOCKET_ENV_NAME); 1343 printf("echo Agent pid %ld;\n", (long)parent_pid); 1344 fflush(stdout); 1345 goto skip; 1346 } 1347 pid = fork(); 1348 if (pid == -1) { 1349 perror("fork"); 1350 cleanup_exit(1); 1351 } 1352 if (pid != 0) { /* Parent - execute the given command. */ 1353 close(sock); 1354 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1355 if (ac == 0) { 1356 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1357 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1358 SSH_AUTHSOCKET_ENV_NAME); 1359 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 1360 SSH_AGENTPID_ENV_NAME); 1361 printf("echo Agent pid %ld;\n", (long)pid); 1362 exit(0); 1363 } 1364 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1365 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1366 perror("setenv"); 1367 exit(1); 1368 } 1369 execvp(av[0], av); 1370 perror(av[0]); 1371 exit(1); 1372 } 1373 /* child */ 1374 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1375 1376 if (setsid() == -1) { 1377 error("setsid: %s", strerror(errno)); 1378 cleanup_exit(1); 1379 } 1380 1381 (void)chdir("/"); 1382 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1383 /* XXX might close listen socket */ 1384 (void)dup2(fd, STDIN_FILENO); 1385 (void)dup2(fd, STDOUT_FILENO); 1386 (void)dup2(fd, STDERR_FILENO); 1387 if (fd > 2) 1388 close(fd); 1389 } 1390 1391 /* deny core dumps, since memory contains unencrypted private keys */ 1392 rlim.rlim_cur = rlim.rlim_max = 0; 1393 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 1394 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1395 cleanup_exit(1); 1396 } 1397 1398 skip: 1399 1400 cleanup_pid = getpid(); 1401 1402 #ifdef ENABLE_PKCS11 1403 pkcs11_init(0); 1404 #endif 1405 new_socket(AUTH_SOCKET, sock); 1406 if (ac > 0) 1407 parent_alive_interval = 10; 1408 idtab_init(); 1409 signal(SIGPIPE, SIG_IGN); 1410 signal(SIGINT, (d_flag | D_flag) ? cleanup_handler : SIG_IGN); 1411 signal(SIGHUP, cleanup_handler); 1412 signal(SIGTERM, cleanup_handler); 1413 nalloc = 0; 1414 1415 if (pledge("stdio rpath cpath unix id proc exec", NULL) == -1) 1416 fatal("%s: pledge: %s", __progname, strerror(errno)); 1417 1418 while (1) { 1419 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp); 1420 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp); 1421 saved_errno = errno; 1422 if (parent_alive_interval != 0) 1423 check_parent_exists(); 1424 (void) reaper(); /* remove expired keys */ 1425 if (result < 0) { 1426 if (saved_errno == EINTR) 1427 continue; 1428 fatal("select: %s", strerror(saved_errno)); 1429 } else if (result > 0) 1430 after_select(readsetp, writesetp); 1431 } 1432 /* NOTREACHED */ 1433 } 1434