1 /* $OpenBSD: ssh-agent.c,v 1.218 2017/03/15 03:52:30 deraadt Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo (at) cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo (at) 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 39 #include <sys/types.h> 40 #include <sys/param.h> 41 #include <sys/resource.h> 42 #include <sys/stat.h> 43 #include <sys/socket.h> 44 #ifdef HAVE_SYS_TIME_H 45 # include <sys/time.h> 46 #endif 47 #ifdef HAVE_SYS_UN_H 48 # include <sys/un.h> 49 #endif 50 #include "openbsd-compat/sys-queue.h" 51 52 #ifdef WITH_OPENSSL 53 #include <openssl/evp.h> 54 #include "openbsd-compat/openssl-compat.h" 55 #endif 56 57 #include <errno.h> 58 #include <fcntl.h> 59 #include <limits.h> 60 #ifdef HAVE_PATHS_H 61 # include <paths.h> 62 #endif 63 #include <signal.h> 64 #include <stdarg.h> 65 #include <stdio.h> 66 #include <stdlib.h> 67 #include <time.h> 68 #include <string.h> 69 #include <unistd.h> 70 #ifdef HAVE_UTIL_H 71 # include <util.h> 72 #endif 73 74 #include "xmalloc.h" 75 #include "ssh.h" 76 #include "rsa.h" 77 #include "sshbuf.h" 78 #include "sshkey.h" 79 #include "authfd.h" 80 #include "compat.h" 81 #include "log.h" 82 #include "misc.h" 83 #include "digest.h" 84 #include "ssherr.h" 85 #include "match.h" 86 87 #ifdef ENABLE_PKCS11 88 #include "ssh-pkcs11.h" 89 #endif 90 91 #ifndef DEFAULT_PKCS11_WHITELIST 92 # define DEFAULT_PKCS11_WHITELIST "/usr/lib*/*,/usr/local/lib*/*" 93 #endif 94 95 typedef enum { 96 AUTH_UNUSED, 97 AUTH_SOCKET, 98 AUTH_CONNECTION 99 } sock_type; 100 101 typedef struct { 102 int fd; 103 sock_type type; 104 struct sshbuf *input; 105 struct sshbuf *output; 106 struct sshbuf *request; 107 } SocketEntry; 108 109 u_int sockets_alloc = 0; 110 SocketEntry *sockets = NULL; 111 112 typedef struct identity { 113 TAILQ_ENTRY(identity) next; 114 struct sshkey *key; 115 char *comment; 116 char *provider; 117 time_t death; 118 u_int confirm; 119 } Identity; 120 121 typedef struct { 122 int nentries; 123 TAILQ_HEAD(idqueue, identity) idlist; 124 } Idtab; 125 126 /* private key table, one per protocol version */ 127 Idtab idtable[3]; 128 129 int max_fd = 0; 130 131 /* pid of shell == parent of agent */ 132 pid_t parent_pid = -1; 133 time_t parent_alive_interval = 0; 134 135 /* pid of process for which cleanup_socket is applicable */ 136 pid_t cleanup_pid = 0; 137 138 /* pathname and directory for AUTH_SOCKET */ 139 char socket_name[PATH_MAX]; 140 char socket_dir[PATH_MAX]; 141 142 /* PKCS#11 path whitelist */ 143 static char *pkcs11_whitelist; 144 145 /* locking */ 146 #define LOCK_SIZE 32 147 #define LOCK_SALT_SIZE 16 148 #define LOCK_ROUNDS 1 149 int locked = 0; 150 u_char lock_pwhash[LOCK_SIZE]; 151 u_char lock_salt[LOCK_SALT_SIZE]; 152 153 extern char *__progname; 154 155 /* Default lifetime in seconds (0 == forever) */ 156 static long lifetime = 0; 157 158 static int fingerprint_hash = SSH_FP_HASH_DEFAULT; 159 160 static void 161 close_socket(SocketEntry *e) 162 { 163 close(e->fd); 164 e->fd = -1; 165 e->type = AUTH_UNUSED; 166 sshbuf_free(e->input); 167 sshbuf_free(e->output); 168 sshbuf_free(e->request); 169 } 170 171 static void 172 idtab_init(void) 173 { 174 int i; 175 176 for (i = 0; i <=2; i++) { 177 TAILQ_INIT(&idtable[i].idlist); 178 idtable[i].nentries = 0; 179 } 180 } 181 182 /* return private key table for requested protocol version */ 183 static Idtab * 184 idtab_lookup(int version) 185 { 186 if (version < 1 || version > 2) 187 fatal("internal error, bad protocol version %d", version); 188 return &idtable[version]; 189 } 190 191 static void 192 free_identity(Identity *id) 193 { 194 sshkey_free(id->key); 195 free(id->provider); 196 free(id->comment); 197 free(id); 198 } 199 200 /* return matching private key for given public key */ 201 static Identity * 202 lookup_identity(struct sshkey *key, int version) 203 { 204 Identity *id; 205 206 Idtab *tab = idtab_lookup(version); 207 TAILQ_FOREACH(id, &tab->idlist, next) { 208 if (sshkey_equal(key, id->key)) 209 return (id); 210 } 211 return (NULL); 212 } 213 214 /* Check confirmation of keysign request */ 215 static int 216 confirm_key(Identity *id) 217 { 218 char *p; 219 int ret = -1; 220 221 p = sshkey_fingerprint(id->key, fingerprint_hash, SSH_FP_DEFAULT); 222 if (p != NULL && 223 ask_permission("Allow use of key %s?\nKey fingerprint %s.", 224 id->comment, p)) 225 ret = 0; 226 free(p); 227 228 return (ret); 229 } 230 231 static void 232 send_status(SocketEntry *e, int success) 233 { 234 int r; 235 236 if ((r = sshbuf_put_u32(e->output, 1)) != 0 || 237 (r = sshbuf_put_u8(e->output, success ? 238 SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0) 239 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 240 } 241 242 /* send list of supported public keys to 'client' */ 243 static void 244 process_request_identities(SocketEntry *e, int version) 245 { 246 Idtab *tab = idtab_lookup(version); 247 Identity *id; 248 struct sshbuf *msg; 249 int r; 250 251 if ((msg = sshbuf_new()) == NULL) 252 fatal("%s: sshbuf_new failed", __func__); 253 if ((r = sshbuf_put_u8(msg, (version == 1) ? 254 SSH_AGENT_RSA_IDENTITIES_ANSWER : 255 SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 256 (r = sshbuf_put_u32(msg, tab->nentries)) != 0) 257 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 258 TAILQ_FOREACH(id, &tab->idlist, next) { 259 if (id->key->type == KEY_RSA1) { 260 #ifdef WITH_SSH1 261 if ((r = sshbuf_put_u32(msg, 262 BN_num_bits(id->key->rsa->n))) != 0 || 263 (r = sshbuf_put_bignum1(msg, 264 id->key->rsa->e)) != 0 || 265 (r = sshbuf_put_bignum1(msg, 266 id->key->rsa->n)) != 0) 267 fatal("%s: buffer error: %s", 268 __func__, ssh_err(r)); 269 #endif 270 } else { 271 u_char *blob; 272 size_t blen; 273 274 if ((r = sshkey_to_blob(id->key, &blob, &blen)) != 0) { 275 error("%s: sshkey_to_blob: %s", __func__, 276 ssh_err(r)); 277 continue; 278 } 279 if ((r = sshbuf_put_string(msg, blob, blen)) != 0) 280 fatal("%s: buffer error: %s", 281 __func__, ssh_err(r)); 282 free(blob); 283 } 284 if ((r = sshbuf_put_cstring(msg, id->comment)) != 0) 285 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 286 } 287 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 288 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 289 sshbuf_free(msg); 290 } 291 292 #ifdef WITH_SSH1 293 /* ssh1 only */ 294 static void 295 process_authentication_challenge1(SocketEntry *e) 296 { 297 u_char buf[32], mdbuf[16], session_id[16]; 298 u_int response_type; 299 BIGNUM *challenge; 300 Identity *id; 301 int r, len; 302 struct sshbuf *msg; 303 struct ssh_digest_ctx *md; 304 struct sshkey *key; 305 306 if ((msg = sshbuf_new()) == NULL) 307 fatal("%s: sshbuf_new failed", __func__); 308 if ((key = sshkey_new(KEY_RSA1)) == NULL) 309 fatal("%s: sshkey_new failed", __func__); 310 if ((challenge = BN_new()) == NULL) 311 fatal("%s: BN_new failed", __func__); 312 313 if ((r = sshbuf_get_u32(e->request, NULL)) != 0 || /* ignored */ 314 (r = sshbuf_get_bignum1(e->request, key->rsa->e)) != 0 || 315 (r = sshbuf_get_bignum1(e->request, key->rsa->n)) != 0 || 316 (r = sshbuf_get_bignum1(e->request, challenge))) 317 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 318 319 /* Only protocol 1.1 is supported */ 320 if (sshbuf_len(e->request) == 0) 321 goto failure; 322 if ((r = sshbuf_get(e->request, session_id, sizeof(session_id))) != 0 || 323 (r = sshbuf_get_u32(e->request, &response_type)) != 0) 324 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 325 if (response_type != 1) 326 goto failure; 327 328 id = lookup_identity(key, 1); 329 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) { 330 struct sshkey *private = id->key; 331 /* Decrypt the challenge using the private key. */ 332 if ((r = rsa_private_decrypt(challenge, challenge, 333 private->rsa) != 0)) { 334 fatal("%s: rsa_public_encrypt: %s", __func__, 335 ssh_err(r)); 336 goto failure; /* XXX ? */ 337 } 338 339 /* The response is MD5 of decrypted challenge plus session id */ 340 len = BN_num_bytes(challenge); 341 if (len <= 0 || len > 32) { 342 logit("%s: bad challenge length %d", __func__, len); 343 goto failure; 344 } 345 memset(buf, 0, 32); 346 BN_bn2bin(challenge, buf + 32 - len); 347 if ((md = ssh_digest_start(SSH_DIGEST_MD5)) == NULL || 348 ssh_digest_update(md, buf, 32) < 0 || 349 ssh_digest_update(md, session_id, 16) < 0 || 350 ssh_digest_final(md, mdbuf, sizeof(mdbuf)) < 0) 351 fatal("%s: md5 failed", __func__); 352 ssh_digest_free(md); 353 354 /* Send the response. */ 355 if ((r = sshbuf_put_u8(msg, SSH_AGENT_RSA_RESPONSE)) != 0 || 356 (r = sshbuf_put(msg, mdbuf, sizeof(mdbuf))) != 0) 357 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 358 goto send; 359 } 360 361 failure: 362 /* Unknown identity or protocol error. Send failure. */ 363 if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0) 364 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 365 send: 366 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 367 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 368 sshkey_free(key); 369 BN_clear_free(challenge); 370 sshbuf_free(msg); 371 } 372 #endif 373 374 static char * 375 agent_decode_alg(struct sshkey *key, u_int flags) 376 { 377 if (key->type == KEY_RSA) { 378 if (flags & SSH_AGENT_RSA_SHA2_256) 379 return "rsa-sha2-256"; 380 else if (flags & SSH_AGENT_RSA_SHA2_512) 381 return "rsa-sha2-512"; 382 } 383 return NULL; 384 } 385 386 /* ssh2 only */ 387 static void 388 process_sign_request2(SocketEntry *e) 389 { 390 u_char *blob, *data, *signature = NULL; 391 size_t blen, dlen, slen = 0; 392 u_int compat = 0, flags; 393 int r, ok = -1; 394 struct sshbuf *msg; 395 struct sshkey *key; 396 struct identity *id; 397 398 if ((msg = sshbuf_new()) == NULL) 399 fatal("%s: sshbuf_new failed", __func__); 400 if ((r = sshbuf_get_string(e->request, &blob, &blen)) != 0 || 401 (r = sshbuf_get_string(e->request, &data, &dlen)) != 0 || 402 (r = sshbuf_get_u32(e->request, &flags)) != 0) 403 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 404 if (flags & SSH_AGENT_OLD_SIGNATURE) 405 compat = SSH_BUG_SIGBLOB; 406 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) { 407 error("%s: cannot parse key blob: %s", __func__, ssh_err(r)); 408 goto send; 409 } 410 if ((id = lookup_identity(key, 2)) == NULL) { 411 verbose("%s: %s key not found", __func__, sshkey_type(key)); 412 goto send; 413 } 414 if (id->confirm && confirm_key(id) != 0) { 415 verbose("%s: user refused key", __func__); 416 goto send; 417 } 418 if ((r = sshkey_sign(id->key, &signature, &slen, 419 data, dlen, agent_decode_alg(key, flags), compat)) != 0) { 420 error("%s: sshkey_sign: %s", __func__, ssh_err(r)); 421 goto send; 422 } 423 /* Success */ 424 ok = 0; 425 send: 426 sshkey_free(key); 427 if (ok == 0) { 428 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 || 429 (r = sshbuf_put_string(msg, signature, slen)) != 0) 430 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 431 } else if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0) 432 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 433 434 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 435 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 436 437 sshbuf_free(msg); 438 free(data); 439 free(blob); 440 free(signature); 441 } 442 443 /* shared */ 444 static void 445 process_remove_identity(SocketEntry *e, int version) 446 { 447 size_t blen; 448 int r, success = 0; 449 struct sshkey *key = NULL; 450 u_char *blob; 451 #ifdef WITH_SSH1 452 u_int bits; 453 #endif /* WITH_SSH1 */ 454 455 switch (version) { 456 #ifdef WITH_SSH1 457 case 1: 458 if ((key = sshkey_new(KEY_RSA1)) == NULL) { 459 error("%s: sshkey_new failed", __func__); 460 return; 461 } 462 if ((r = sshbuf_get_u32(e->request, &bits)) != 0 || 463 (r = sshbuf_get_bignum1(e->request, key->rsa->e)) != 0 || 464 (r = sshbuf_get_bignum1(e->request, key->rsa->n)) != 0) 465 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 466 467 if (bits != sshkey_size(key)) 468 logit("Warning: identity keysize mismatch: " 469 "actual %u, announced %u", 470 sshkey_size(key), bits); 471 break; 472 #endif /* WITH_SSH1 */ 473 case 2: 474 if ((r = sshbuf_get_string(e->request, &blob, &blen)) != 0) 475 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 476 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) 477 error("%s: sshkey_from_blob failed: %s", 478 __func__, ssh_err(r)); 479 free(blob); 480 break; 481 } 482 if (key != NULL) { 483 Identity *id = lookup_identity(key, version); 484 if (id != NULL) { 485 /* 486 * We have this key. Free the old key. Since we 487 * don't want to leave empty slots in the middle of 488 * the array, we actually free the key there and move 489 * all the entries between the empty slot and the end 490 * of the array. 491 */ 492 Idtab *tab = idtab_lookup(version); 493 if (tab->nentries < 1) 494 fatal("process_remove_identity: " 495 "internal error: tab->nentries %d", 496 tab->nentries); 497 TAILQ_REMOVE(&tab->idlist, id, next); 498 free_identity(id); 499 tab->nentries--; 500 success = 1; 501 } 502 sshkey_free(key); 503 } 504 send_status(e, success); 505 } 506 507 static void 508 process_remove_all_identities(SocketEntry *e, int version) 509 { 510 Idtab *tab = idtab_lookup(version); 511 Identity *id; 512 513 /* Loop over all identities and clear the keys. */ 514 for (id = TAILQ_FIRST(&tab->idlist); id; 515 id = TAILQ_FIRST(&tab->idlist)) { 516 TAILQ_REMOVE(&tab->idlist, id, next); 517 free_identity(id); 518 } 519 520 /* Mark that there are no identities. */ 521 tab->nentries = 0; 522 523 /* Send success. */ 524 send_status(e, 1); 525 } 526 527 /* removes expired keys and returns number of seconds until the next expiry */ 528 static time_t 529 reaper(void) 530 { 531 time_t deadline = 0, now = monotime(); 532 Identity *id, *nxt; 533 int version; 534 Idtab *tab; 535 536 for (version = 1; version < 3; version++) { 537 tab = idtab_lookup(version); 538 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 539 nxt = TAILQ_NEXT(id, next); 540 if (id->death == 0) 541 continue; 542 if (now >= id->death) { 543 debug("expiring key '%s'", id->comment); 544 TAILQ_REMOVE(&tab->idlist, id, next); 545 free_identity(id); 546 tab->nentries--; 547 } else 548 deadline = (deadline == 0) ? id->death : 549 MINIMUM(deadline, id->death); 550 } 551 } 552 if (deadline == 0 || deadline <= now) 553 return 0; 554 else 555 return (deadline - now); 556 } 557 558 /* 559 * XXX this and the corresponding serialisation function probably belongs 560 * in key.c 561 */ 562 #ifdef WITH_SSH1 563 static int 564 agent_decode_rsa1(struct sshbuf *m, struct sshkey **kp) 565 { 566 struct sshkey *k = NULL; 567 int r = SSH_ERR_INTERNAL_ERROR; 568 569 *kp = NULL; 570 if ((k = sshkey_new_private(KEY_RSA1)) == NULL) 571 return SSH_ERR_ALLOC_FAIL; 572 573 if ((r = sshbuf_get_u32(m, NULL)) != 0 || /* ignored */ 574 (r = sshbuf_get_bignum1(m, k->rsa->n)) != 0 || 575 (r = sshbuf_get_bignum1(m, k->rsa->e)) != 0 || 576 (r = sshbuf_get_bignum1(m, k->rsa->d)) != 0 || 577 (r = sshbuf_get_bignum1(m, k->rsa->iqmp)) != 0 || 578 /* SSH1 and SSL have p and q swapped */ 579 (r = sshbuf_get_bignum1(m, k->rsa->q)) != 0 || /* p */ 580 (r = sshbuf_get_bignum1(m, k->rsa->p)) != 0) /* q */ 581 goto out; 582 583 /* Generate additional parameters */ 584 if ((r = rsa_generate_additional_parameters(k->rsa)) != 0) 585 goto out; 586 /* enable blinding */ 587 if (RSA_blinding_on(k->rsa, NULL) != 1) { 588 r = SSH_ERR_LIBCRYPTO_ERROR; 589 goto out; 590 } 591 592 r = 0; /* success */ 593 out: 594 if (r == 0) 595 *kp = k; 596 else 597 sshkey_free(k); 598 return r; 599 } 600 #endif /* WITH_SSH1 */ 601 602 static void 603 process_add_identity(SocketEntry *e, int version) 604 { 605 Idtab *tab = idtab_lookup(version); 606 Identity *id; 607 int success = 0, confirm = 0; 608 u_int seconds; 609 char *comment = NULL; 610 time_t death = 0; 611 struct sshkey *k = NULL; 612 u_char ctype; 613 int r = SSH_ERR_INTERNAL_ERROR; 614 615 switch (version) { 616 #ifdef WITH_SSH1 617 case 1: 618 r = agent_decode_rsa1(e->request, &k); 619 break; 620 #endif /* WITH_SSH1 */ 621 case 2: 622 r = sshkey_private_deserialize(e->request, &k); 623 break; 624 } 625 if (r != 0 || k == NULL || 626 (r = sshbuf_get_cstring(e->request, &comment, NULL)) != 0) { 627 error("%s: decode private key: %s", __func__, ssh_err(r)); 628 goto err; 629 } 630 631 while (sshbuf_len(e->request)) { 632 if ((r = sshbuf_get_u8(e->request, &ctype)) != 0) { 633 error("%s: buffer error: %s", __func__, ssh_err(r)); 634 goto err; 635 } 636 switch (ctype) { 637 case SSH_AGENT_CONSTRAIN_LIFETIME: 638 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) { 639 error("%s: bad lifetime constraint: %s", 640 __func__, ssh_err(r)); 641 goto err; 642 } 643 death = monotime() + seconds; 644 break; 645 case SSH_AGENT_CONSTRAIN_CONFIRM: 646 confirm = 1; 647 break; 648 default: 649 error("%s: Unknown constraint %d", __func__, ctype); 650 err: 651 sshbuf_reset(e->request); 652 free(comment); 653 sshkey_free(k); 654 goto send; 655 } 656 } 657 658 success = 1; 659 if (lifetime && !death) 660 death = monotime() + lifetime; 661 if ((id = lookup_identity(k, version)) == NULL) { 662 id = xcalloc(1, sizeof(Identity)); 663 id->key = k; 664 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 665 /* Increment the number of identities. */ 666 tab->nentries++; 667 } else { 668 sshkey_free(k); 669 free(id->comment); 670 } 671 id->comment = comment; 672 id->death = death; 673 id->confirm = confirm; 674 send: 675 send_status(e, success); 676 } 677 678 /* XXX todo: encrypt sensitive data with passphrase */ 679 static void 680 process_lock_agent(SocketEntry *e, int lock) 681 { 682 int r, success = 0, delay; 683 char *passwd; 684 u_char passwdhash[LOCK_SIZE]; 685 static u_int fail_count = 0; 686 size_t pwlen; 687 688 if ((r = sshbuf_get_cstring(e->request, &passwd, &pwlen)) != 0) 689 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 690 if (pwlen == 0) { 691 debug("empty password not supported"); 692 } else if (locked && !lock) { 693 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 694 passwdhash, sizeof(passwdhash), LOCK_ROUNDS) < 0) 695 fatal("bcrypt_pbkdf"); 696 if (timingsafe_bcmp(passwdhash, lock_pwhash, LOCK_SIZE) == 0) { 697 debug("agent unlocked"); 698 locked = 0; 699 fail_count = 0; 700 explicit_bzero(lock_pwhash, sizeof(lock_pwhash)); 701 success = 1; 702 } else { 703 /* delay in 0.1s increments up to 10s */ 704 if (fail_count < 100) 705 fail_count++; 706 delay = 100000 * fail_count; 707 debug("unlock failed, delaying %0.1lf seconds", 708 (double)delay/1000000); 709 usleep(delay); 710 } 711 explicit_bzero(passwdhash, sizeof(passwdhash)); 712 } else if (!locked && lock) { 713 debug("agent locked"); 714 locked = 1; 715 arc4random_buf(lock_salt, sizeof(lock_salt)); 716 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 717 lock_pwhash, sizeof(lock_pwhash), LOCK_ROUNDS) < 0) 718 fatal("bcrypt_pbkdf"); 719 success = 1; 720 } 721 explicit_bzero(passwd, pwlen); 722 free(passwd); 723 send_status(e, success); 724 } 725 726 static void 727 no_identities(SocketEntry *e, u_int type) 728 { 729 struct sshbuf *msg; 730 int r; 731 732 if ((msg = sshbuf_new()) == NULL) 733 fatal("%s: sshbuf_new failed", __func__); 734 if ((r = sshbuf_put_u8(msg, 735 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ? 736 SSH_AGENT_RSA_IDENTITIES_ANSWER : 737 SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 738 (r = sshbuf_put_u32(msg, 0)) != 0 || 739 (r = sshbuf_put_stringb(e->output, msg)) != 0) 740 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 741 sshbuf_free(msg); 742 } 743 744 #ifdef ENABLE_PKCS11 745 static void 746 process_add_smartcard_key(SocketEntry *e) 747 { 748 char *provider = NULL, *pin, canonical_provider[PATH_MAX]; 749 int r, i, version, count = 0, success = 0, confirm = 0; 750 u_int seconds; 751 time_t death = 0; 752 u_char type; 753 struct sshkey **keys = NULL, *k; 754 Identity *id; 755 Idtab *tab; 756 757 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 758 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) 759 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 760 761 while (sshbuf_len(e->request)) { 762 if ((r = sshbuf_get_u8(e->request, &type)) != 0) 763 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 764 switch (type) { 765 case SSH_AGENT_CONSTRAIN_LIFETIME: 766 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) 767 fatal("%s: buffer error: %s", 768 __func__, ssh_err(r)); 769 death = monotime() + seconds; 770 break; 771 case SSH_AGENT_CONSTRAIN_CONFIRM: 772 confirm = 1; 773 break; 774 default: 775 error("process_add_smartcard_key: " 776 "Unknown constraint type %d", type); 777 goto send; 778 } 779 } 780 if (realpath(provider, canonical_provider) == NULL) { 781 verbose("failed PKCS#11 add of \"%.100s\": realpath: %s", 782 provider, strerror(errno)); 783 goto send; 784 } 785 if (match_pattern_list(canonical_provider, pkcs11_whitelist, 0) != 1) { 786 verbose("refusing PKCS#11 add of \"%.100s\": " 787 "provider not whitelisted", canonical_provider); 788 goto send; 789 } 790 debug("%s: add %.100s", __func__, canonical_provider); 791 if (lifetime && !death) 792 death = monotime() + lifetime; 793 794 count = pkcs11_add_provider(canonical_provider, pin, &keys); 795 for (i = 0; i < count; i++) { 796 k = keys[i]; 797 version = k->type == KEY_RSA1 ? 1 : 2; 798 tab = idtab_lookup(version); 799 if (lookup_identity(k, version) == NULL) { 800 id = xcalloc(1, sizeof(Identity)); 801 id->key = k; 802 id->provider = xstrdup(canonical_provider); 803 id->comment = xstrdup(canonical_provider); /* XXX */ 804 id->death = death; 805 id->confirm = confirm; 806 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 807 tab->nentries++; 808 success = 1; 809 } else { 810 sshkey_free(k); 811 } 812 keys[i] = NULL; 813 } 814 send: 815 free(pin); 816 free(provider); 817 free(keys); 818 send_status(e, success); 819 } 820 821 static void 822 process_remove_smartcard_key(SocketEntry *e) 823 { 824 char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX]; 825 int r, version, success = 0; 826 Identity *id, *nxt; 827 Idtab *tab; 828 829 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 830 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) 831 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 832 free(pin); 833 834 if (realpath(provider, canonical_provider) == NULL) { 835 verbose("failed PKCS#11 add of \"%.100s\": realpath: %s", 836 provider, strerror(errno)); 837 goto send; 838 } 839 840 debug("%s: remove %.100s", __func__, canonical_provider); 841 for (version = 1; version < 3; version++) { 842 tab = idtab_lookup(version); 843 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 844 nxt = TAILQ_NEXT(id, next); 845 /* Skip file--based keys */ 846 if (id->provider == NULL) 847 continue; 848 if (!strcmp(canonical_provider, id->provider)) { 849 TAILQ_REMOVE(&tab->idlist, id, next); 850 free_identity(id); 851 tab->nentries--; 852 } 853 } 854 } 855 if (pkcs11_del_provider(canonical_provider) == 0) 856 success = 1; 857 else 858 error("process_remove_smartcard_key:" 859 " pkcs11_del_provider failed"); 860 send: 861 free(provider); 862 send_status(e, success); 863 } 864 #endif /* ENABLE_PKCS11 */ 865 866 /* dispatch incoming messages */ 867 868 static void 869 process_message(SocketEntry *e) 870 { 871 u_int msg_len; 872 u_char type; 873 const u_char *cp; 874 int r; 875 876 if (sshbuf_len(e->input) < 5) 877 return; /* Incomplete message. */ 878 cp = sshbuf_ptr(e->input); 879 msg_len = PEEK_U32(cp); 880 if (msg_len > 256 * 1024) { 881 close_socket(e); 882 return; 883 } 884 if (sshbuf_len(e->input) < msg_len + 4) 885 return; 886 887 /* move the current input to e->request */ 888 sshbuf_reset(e->request); 889 if ((r = sshbuf_get_stringb(e->input, e->request)) != 0 || 890 (r = sshbuf_get_u8(e->request, &type)) != 0) 891 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 892 893 /* check wheter agent is locked */ 894 if (locked && type != SSH_AGENTC_UNLOCK) { 895 sshbuf_reset(e->request); 896 switch (type) { 897 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 898 case SSH2_AGENTC_REQUEST_IDENTITIES: 899 /* send empty lists */ 900 no_identities(e, type); 901 break; 902 default: 903 /* send a fail message for all other request types */ 904 send_status(e, 0); 905 } 906 return; 907 } 908 909 debug("type %d", type); 910 switch (type) { 911 case SSH_AGENTC_LOCK: 912 case SSH_AGENTC_UNLOCK: 913 process_lock_agent(e, type == SSH_AGENTC_LOCK); 914 break; 915 #ifdef WITH_SSH1 916 /* ssh1 */ 917 case SSH_AGENTC_RSA_CHALLENGE: 918 process_authentication_challenge1(e); 919 break; 920 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 921 process_request_identities(e, 1); 922 break; 923 case SSH_AGENTC_ADD_RSA_IDENTITY: 924 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 925 process_add_identity(e, 1); 926 break; 927 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 928 process_remove_identity(e, 1); 929 break; 930 #endif 931 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 932 process_remove_all_identities(e, 1); /* safe for !WITH_SSH1 */ 933 break; 934 /* ssh2 */ 935 case SSH2_AGENTC_SIGN_REQUEST: 936 process_sign_request2(e); 937 break; 938 case SSH2_AGENTC_REQUEST_IDENTITIES: 939 process_request_identities(e, 2); 940 break; 941 case SSH2_AGENTC_ADD_IDENTITY: 942 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 943 process_add_identity(e, 2); 944 break; 945 case SSH2_AGENTC_REMOVE_IDENTITY: 946 process_remove_identity(e, 2); 947 break; 948 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 949 process_remove_all_identities(e, 2); 950 break; 951 #ifdef ENABLE_PKCS11 952 case SSH_AGENTC_ADD_SMARTCARD_KEY: 953 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 954 process_add_smartcard_key(e); 955 break; 956 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 957 process_remove_smartcard_key(e); 958 break; 959 #endif /* ENABLE_PKCS11 */ 960 default: 961 /* Unknown message. Respond with failure. */ 962 error("Unknown message %d", type); 963 sshbuf_reset(e->request); 964 send_status(e, 0); 965 break; 966 } 967 } 968 969 static void 970 new_socket(sock_type type, int fd) 971 { 972 u_int i, old_alloc, new_alloc; 973 974 set_nonblock(fd); 975 976 if (fd > max_fd) 977 max_fd = fd; 978 979 for (i = 0; i < sockets_alloc; i++) 980 if (sockets[i].type == AUTH_UNUSED) { 981 sockets[i].fd = fd; 982 if ((sockets[i].input = sshbuf_new()) == NULL) 983 fatal("%s: sshbuf_new failed", __func__); 984 if ((sockets[i].output = sshbuf_new()) == NULL) 985 fatal("%s: sshbuf_new failed", __func__); 986 if ((sockets[i].request = sshbuf_new()) == NULL) 987 fatal("%s: sshbuf_new failed", __func__); 988 sockets[i].type = type; 989 return; 990 } 991 old_alloc = sockets_alloc; 992 new_alloc = sockets_alloc + 10; 993 sockets = xreallocarray(sockets, new_alloc, sizeof(sockets[0])); 994 for (i = old_alloc; i < new_alloc; i++) 995 sockets[i].type = AUTH_UNUSED; 996 sockets_alloc = new_alloc; 997 sockets[old_alloc].fd = fd; 998 if ((sockets[old_alloc].input = sshbuf_new()) == NULL) 999 fatal("%s: sshbuf_new failed", __func__); 1000 if ((sockets[old_alloc].output = sshbuf_new()) == NULL) 1001 fatal("%s: sshbuf_new failed", __func__); 1002 if ((sockets[old_alloc].request = sshbuf_new()) == NULL) 1003 fatal("%s: sshbuf_new failed", __func__); 1004 sockets[old_alloc].type = type; 1005 } 1006 1007 static int 1008 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp, 1009 struct timeval **tvpp) 1010 { 1011 u_int i, sz; 1012 int n = 0; 1013 static struct timeval tv; 1014 time_t deadline; 1015 1016 for (i = 0; i < sockets_alloc; i++) { 1017 switch (sockets[i].type) { 1018 case AUTH_SOCKET: 1019 case AUTH_CONNECTION: 1020 n = MAXIMUM(n, sockets[i].fd); 1021 break; 1022 case AUTH_UNUSED: 1023 break; 1024 default: 1025 fatal("Unknown socket type %d", sockets[i].type); 1026 break; 1027 } 1028 } 1029 1030 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 1031 if (*fdrp == NULL || sz > *nallocp) { 1032 free(*fdrp); 1033 free(*fdwp); 1034 *fdrp = xmalloc(sz); 1035 *fdwp = xmalloc(sz); 1036 *nallocp = sz; 1037 } 1038 if (n < *fdl) 1039 debug("XXX shrink: %d < %d", n, *fdl); 1040 *fdl = n; 1041 memset(*fdrp, 0, sz); 1042 memset(*fdwp, 0, sz); 1043 1044 for (i = 0; i < sockets_alloc; i++) { 1045 switch (sockets[i].type) { 1046 case AUTH_SOCKET: 1047 case AUTH_CONNECTION: 1048 FD_SET(sockets[i].fd, *fdrp); 1049 if (sshbuf_len(sockets[i].output) > 0) 1050 FD_SET(sockets[i].fd, *fdwp); 1051 break; 1052 default: 1053 break; 1054 } 1055 } 1056 deadline = reaper(); 1057 if (parent_alive_interval != 0) 1058 deadline = (deadline == 0) ? parent_alive_interval : 1059 MINIMUM(deadline, parent_alive_interval); 1060 if (deadline == 0) { 1061 *tvpp = NULL; 1062 } else { 1063 tv.tv_sec = deadline; 1064 tv.tv_usec = 0; 1065 *tvpp = &tv; 1066 } 1067 return (1); 1068 } 1069 1070 static void 1071 after_select(fd_set *readset, fd_set *writeset) 1072 { 1073 struct sockaddr_un sunaddr; 1074 socklen_t slen; 1075 char buf[1024]; 1076 int len, sock, r; 1077 u_int i, orig_alloc; 1078 uid_t euid; 1079 gid_t egid; 1080 1081 for (i = 0, orig_alloc = sockets_alloc; i < orig_alloc; i++) 1082 switch (sockets[i].type) { 1083 case AUTH_UNUSED: 1084 break; 1085 case AUTH_SOCKET: 1086 if (FD_ISSET(sockets[i].fd, readset)) { 1087 slen = sizeof(sunaddr); 1088 sock = accept(sockets[i].fd, 1089 (struct sockaddr *)&sunaddr, &slen); 1090 if (sock < 0) { 1091 error("accept from AUTH_SOCKET: %s", 1092 strerror(errno)); 1093 break; 1094 } 1095 if (getpeereid(sock, &euid, &egid) < 0) { 1096 error("getpeereid %d failed: %s", 1097 sock, strerror(errno)); 1098 close(sock); 1099 break; 1100 } 1101 if ((euid != 0) && (getuid() != euid)) { 1102 error("uid mismatch: " 1103 "peer euid %u != uid %u", 1104 (u_int) euid, (u_int) getuid()); 1105 close(sock); 1106 break; 1107 } 1108 new_socket(AUTH_CONNECTION, sock); 1109 } 1110 break; 1111 case AUTH_CONNECTION: 1112 if (sshbuf_len(sockets[i].output) > 0 && 1113 FD_ISSET(sockets[i].fd, writeset)) { 1114 len = write(sockets[i].fd, 1115 sshbuf_ptr(sockets[i].output), 1116 sshbuf_len(sockets[i].output)); 1117 if (len == -1 && (errno == EAGAIN || 1118 errno == EWOULDBLOCK || 1119 errno == EINTR)) 1120 continue; 1121 if (len <= 0) { 1122 close_socket(&sockets[i]); 1123 break; 1124 } 1125 if ((r = sshbuf_consume(sockets[i].output, 1126 len)) != 0) 1127 fatal("%s: buffer error: %s", 1128 __func__, ssh_err(r)); 1129 } 1130 if (FD_ISSET(sockets[i].fd, readset)) { 1131 len = read(sockets[i].fd, buf, sizeof(buf)); 1132 if (len == -1 && (errno == EAGAIN || 1133 errno == EWOULDBLOCK || 1134 errno == EINTR)) 1135 continue; 1136 if (len <= 0) { 1137 close_socket(&sockets[i]); 1138 break; 1139 } 1140 if ((r = sshbuf_put(sockets[i].input, 1141 buf, len)) != 0) 1142 fatal("%s: buffer error: %s", 1143 __func__, ssh_err(r)); 1144 explicit_bzero(buf, sizeof(buf)); 1145 process_message(&sockets[i]); 1146 } 1147 break; 1148 default: 1149 fatal("Unknown type %d", sockets[i].type); 1150 } 1151 } 1152 1153 static void 1154 cleanup_socket(void) 1155 { 1156 if (cleanup_pid != 0 && getpid() != cleanup_pid) 1157 return; 1158 debug("%s: cleanup", __func__); 1159 if (socket_name[0]) 1160 unlink(socket_name); 1161 if (socket_dir[0]) 1162 rmdir(socket_dir); 1163 } 1164 1165 void 1166 cleanup_exit(int i) 1167 { 1168 cleanup_socket(); 1169 _exit(i); 1170 } 1171 1172 /*ARGSUSED*/ 1173 static void 1174 cleanup_handler(int sig) 1175 { 1176 cleanup_socket(); 1177 #ifdef ENABLE_PKCS11 1178 pkcs11_terminate(); 1179 #endif 1180 _exit(2); 1181 } 1182 1183 static void 1184 check_parent_exists(void) 1185 { 1186 /* 1187 * If our parent has exited then getppid() will return (pid_t)1, 1188 * so testing for that should be safe. 1189 */ 1190 if (parent_pid != -1 && getppid() != parent_pid) { 1191 /* printf("Parent has died - Authentication agent exiting.\n"); */ 1192 cleanup_socket(); 1193 _exit(2); 1194 } 1195 } 1196 1197 static void 1198 usage(void) 1199 { 1200 fprintf(stderr, 1201 "usage: ssh-agent [-c | -s] [-Dd] [-a bind_address] [-E fingerprint_hash]\n" 1202 " [-P pkcs11_whitelist] [-t life] [command [arg ...]]\n" 1203 " ssh-agent [-c | -s] -k\n"); 1204 exit(1); 1205 } 1206 1207 int 1208 main(int ac, char **av) 1209 { 1210 int c_flag = 0, d_flag = 0, D_flag = 0, k_flag = 0, s_flag = 0; 1211 int sock, fd, ch, result, saved_errno; 1212 u_int nalloc; 1213 char *shell, *format, *pidstr, *agentsocket = NULL; 1214 fd_set *readsetp = NULL, *writesetp = NULL; 1215 #ifdef HAVE_SETRLIMIT 1216 struct rlimit rlim; 1217 #endif 1218 extern int optind; 1219 extern char *optarg; 1220 pid_t pid; 1221 char pidstrbuf[1 + 3 * sizeof pid]; 1222 struct timeval *tvp = NULL; 1223 size_t len; 1224 mode_t prev_mask; 1225 1226 ssh_malloc_init(); /* must be called before any mallocs */ 1227 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1228 sanitise_stdfd(); 1229 1230 /* drop */ 1231 setegid(getgid()); 1232 setgid(getgid()); 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:P:t:")) != -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 'P': 1259 if (pkcs11_whitelist != NULL) 1260 fatal("-P option already specified"); 1261 pkcs11_whitelist = xstrdup(optarg); 1262 break; 1263 case 's': 1264 if (c_flag) 1265 usage(); 1266 s_flag++; 1267 break; 1268 case 'd': 1269 if (d_flag || D_flag) 1270 usage(); 1271 d_flag++; 1272 break; 1273 case 'D': 1274 if (d_flag || D_flag) 1275 usage(); 1276 D_flag++; 1277 break; 1278 case 'a': 1279 agentsocket = optarg; 1280 break; 1281 case 't': 1282 if ((lifetime = convtime(optarg)) == -1) { 1283 fprintf(stderr, "Invalid lifetime\n"); 1284 usage(); 1285 } 1286 break; 1287 default: 1288 usage(); 1289 } 1290 } 1291 ac -= optind; 1292 av += optind; 1293 1294 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag || D_flag)) 1295 usage(); 1296 1297 if (pkcs11_whitelist == NULL) 1298 pkcs11_whitelist = xstrdup(DEFAULT_PKCS11_WHITELIST); 1299 1300 if (ac == 0 && !c_flag && !s_flag) { 1301 shell = getenv("SHELL"); 1302 if (shell != NULL && (len = strlen(shell)) > 2 && 1303 strncmp(shell + len - 3, "csh", 3) == 0) 1304 c_flag = 1; 1305 } 1306 if (k_flag) { 1307 const char *errstr = NULL; 1308 1309 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1310 if (pidstr == NULL) { 1311 fprintf(stderr, "%s not set, cannot kill agent\n", 1312 SSH_AGENTPID_ENV_NAME); 1313 exit(1); 1314 } 1315 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr); 1316 if (errstr) { 1317 fprintf(stderr, 1318 "%s=\"%s\", which is not a good PID: %s\n", 1319 SSH_AGENTPID_ENV_NAME, pidstr, errstr); 1320 exit(1); 1321 } 1322 if (kill(pid, SIGTERM) == -1) { 1323 perror("kill"); 1324 exit(1); 1325 } 1326 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 1327 printf(format, SSH_AUTHSOCKET_ENV_NAME); 1328 printf(format, SSH_AGENTPID_ENV_NAME); 1329 printf("echo Agent pid %ld killed;\n", (long)pid); 1330 exit(0); 1331 } 1332 parent_pid = getpid(); 1333 1334 if (agentsocket == NULL) { 1335 /* Create private directory for agent socket */ 1336 mktemp_proto(socket_dir, sizeof(socket_dir)); 1337 if (mkdtemp(socket_dir) == NULL) { 1338 perror("mkdtemp: private socket dir"); 1339 exit(1); 1340 } 1341 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1342 (long)parent_pid); 1343 } else { 1344 /* Try to use specified agent socket */ 1345 socket_dir[0] = '\0'; 1346 strlcpy(socket_name, agentsocket, sizeof socket_name); 1347 } 1348 1349 /* 1350 * Create socket early so it will exist before command gets run from 1351 * the parent. 1352 */ 1353 prev_mask = umask(0177); 1354 sock = unix_listener(socket_name, SSH_LISTEN_BACKLOG, 0); 1355 if (sock < 0) { 1356 /* XXX - unix_listener() calls error() not perror() */ 1357 *socket_name = '\0'; /* Don't unlink any existing file */ 1358 cleanup_exit(1); 1359 } 1360 umask(prev_mask); 1361 1362 /* 1363 * Fork, and have the parent execute the command, if any, or present 1364 * the socket data. The child continues as the authentication agent. 1365 */ 1366 if (D_flag || d_flag) { 1367 log_init(__progname, 1368 d_flag ? SYSLOG_LEVEL_DEBUG3 : SYSLOG_LEVEL_INFO, 1369 SYSLOG_FACILITY_AUTH, 1); 1370 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1371 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1372 SSH_AUTHSOCKET_ENV_NAME); 1373 printf("echo Agent pid %ld;\n", (long)parent_pid); 1374 fflush(stdout); 1375 goto skip; 1376 } 1377 pid = fork(); 1378 if (pid == -1) { 1379 perror("fork"); 1380 cleanup_exit(1); 1381 } 1382 if (pid != 0) { /* Parent - execute the given command. */ 1383 close(sock); 1384 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1385 if (ac == 0) { 1386 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1387 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1388 SSH_AUTHSOCKET_ENV_NAME); 1389 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 1390 SSH_AGENTPID_ENV_NAME); 1391 printf("echo Agent pid %ld;\n", (long)pid); 1392 exit(0); 1393 } 1394 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1395 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1396 perror("setenv"); 1397 exit(1); 1398 } 1399 execvp(av[0], av); 1400 perror(av[0]); 1401 exit(1); 1402 } 1403 /* child */ 1404 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1405 1406 if (setsid() == -1) { 1407 error("setsid: %s", strerror(errno)); 1408 cleanup_exit(1); 1409 } 1410 1411 (void)chdir("/"); 1412 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1413 /* XXX might close listen socket */ 1414 (void)dup2(fd, STDIN_FILENO); 1415 (void)dup2(fd, STDOUT_FILENO); 1416 (void)dup2(fd, STDERR_FILENO); 1417 if (fd > 2) 1418 close(fd); 1419 } 1420 1421 #ifdef HAVE_SETRLIMIT 1422 /* deny core dumps, since memory contains unencrypted private keys */ 1423 rlim.rlim_cur = rlim.rlim_max = 0; 1424 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 1425 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1426 cleanup_exit(1); 1427 } 1428 #endif 1429 1430 skip: 1431 1432 cleanup_pid = getpid(); 1433 1434 #ifdef ENABLE_PKCS11 1435 pkcs11_init(0); 1436 #endif 1437 new_socket(AUTH_SOCKET, sock); 1438 if (ac > 0) 1439 parent_alive_interval = 10; 1440 idtab_init(); 1441 signal(SIGPIPE, SIG_IGN); 1442 signal(SIGINT, (d_flag | D_flag) ? cleanup_handler : SIG_IGN); 1443 signal(SIGHUP, cleanup_handler); 1444 signal(SIGTERM, cleanup_handler); 1445 nalloc = 0; 1446 1447 if (pledge("stdio rpath cpath unix id proc exec", NULL) == -1) 1448 fatal("%s: pledge: %s", __progname, strerror(errno)); 1449 platform_pledge_agent(); 1450 1451 while (1) { 1452 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp); 1453 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp); 1454 saved_errno = errno; 1455 if (parent_alive_interval != 0) 1456 check_parent_exists(); 1457 (void) reaper(); /* remove expired keys */ 1458 if (result < 0) { 1459 if (saved_errno == EINTR) 1460 continue; 1461 fatal("select: %s", strerror(saved_errno)); 1462 } else if (result > 0) 1463 after_select(readsetp, writesetp); 1464 } 1465 /* NOTREACHED */ 1466 } 1467
