1 /* $NetBSD: ssh-agent.c,v 1.19 2016/12/25 00:07:47 christos Exp $ */ 2 /* $OpenBSD: ssh-agent.c,v 1.215 2016/11/30 03:07:37 djm Exp $ */ 3 4 /* 5 * Author: Tatu Ylonen <ylo@cs.hut.fi> 6 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 7 * All rights reserved 8 * The authentication agent program. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 * 16 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 17 * 18 * Redistribution and use in source and binary forms, with or without 19 * modification, are permitted provided that the following conditions 20 * are met: 21 * 1. Redistributions of source code must retain the above copyright 22 * notice, this list of conditions and the following disclaimer. 23 * 2. Redistributions in binary form must reproduce the above copyright 24 * notice, this list of conditions and the following disclaimer in the 25 * documentation and/or other materials provided with the distribution. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 28 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 29 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 30 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 31 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 32 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 33 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 34 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 35 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 36 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 #include "includes.h" 40 __RCSID("$NetBSD: ssh-agent.c,v 1.19 2016/12/25 00:07:47 christos Exp $"); 41 42 #include <sys/param.h> /* MIN MAX */ 43 #include <sys/types.h> 44 #include <sys/time.h> 45 #include <sys/queue.h> 46 #include <sys/resource.h> 47 #include <sys/socket.h> 48 #include <sys/stat.h> 49 #include <sys/un.h> 50 51 #ifdef WITH_OPENSSL 52 #include <openssl/evp.h> 53 #endif 54 55 #include <errno.h> 56 #include <fcntl.h> 57 #include <paths.h> 58 #include <signal.h> 59 #include <stdlib.h> 60 #include <stdio.h> 61 #include <string.h> 62 #include <limits.h> 63 #include <time.h> 64 #include <unistd.h> 65 #include <util.h> 66 67 #include "xmalloc.h" 68 #include "ssh.h" 69 #include "rsa.h" 70 #include "sshbuf.h" 71 #include "sshkey.h" 72 #include "authfd.h" 73 #include "compat.h" 74 #include "log.h" 75 #include "misc.h" 76 #include "getpeereid.h" 77 #include "digest.h" 78 #include "ssherr.h" 79 #include "match.h" 80 81 #ifdef ENABLE_PKCS11 82 #include "ssh-pkcs11.h" 83 #endif 84 85 #ifndef DEFAULT_PKCS11_WHITELIST 86 # define DEFAULT_PKCS11_WHITELIST "/usr/lib/*,/usr/local/lib/*" 87 #endif 88 89 typedef enum { 90 AUTH_UNUSED, 91 AUTH_SOCKET, 92 AUTH_CONNECTION 93 } sock_type; 94 95 typedef struct { 96 int fd; 97 sock_type type; 98 struct sshbuf *input; 99 struct sshbuf *output; 100 struct sshbuf *request; 101 } SocketEntry; 102 103 u_int sockets_alloc = 0; 104 SocketEntry *sockets = NULL; 105 106 typedef struct identity { 107 TAILQ_ENTRY(identity) next; 108 struct sshkey *key; 109 char *comment; 110 char *provider; 111 time_t death; 112 u_int confirm; 113 } Identity; 114 115 typedef struct { 116 int nentries; 117 TAILQ_HEAD(idqueue, identity) idlist; 118 } Idtab; 119 120 /* private key table, one per protocol version */ 121 Idtab idtable[3]; 122 123 int max_fd = 0; 124 125 /* pid of shell == parent of agent */ 126 pid_t parent_pid = -1; 127 time_t parent_alive_interval = 0; 128 129 /* pid of process for which cleanup_socket is applicable */ 130 pid_t cleanup_pid = 0; 131 132 /* pathname and directory for AUTH_SOCKET */ 133 char socket_name[PATH_MAX]; 134 char socket_dir[PATH_MAX]; 135 136 /* PKCS#11 path whitelist */ 137 static char *pkcs11_whitelist; 138 139 /* locking */ 140 #define LOCK_SIZE 32 141 #define LOCK_SALT_SIZE 16 142 #define LOCK_ROUNDS 1 143 int locked = 0; 144 u_char lock_pwhash[LOCK_SIZE]; 145 u_char lock_salt[LOCK_SALT_SIZE]; 146 147 extern char *__progname; 148 149 /* Default lifetime in seconds (0 == forever) */ 150 static long lifetime = 0; 151 152 static int fingerprint_hash = SSH_FP_HASH_DEFAULT; 153 154 static void 155 close_socket(SocketEntry *e) 156 { 157 close(e->fd); 158 e->fd = -1; 159 e->type = AUTH_UNUSED; 160 sshbuf_free(e->input); 161 sshbuf_free(e->output); 162 sshbuf_free(e->request); 163 } 164 165 static void 166 idtab_init(void) 167 { 168 int i; 169 170 for (i = 0; i <=2; i++) { 171 TAILQ_INIT(&idtable[i].idlist); 172 idtable[i].nentries = 0; 173 } 174 } 175 176 /* return private key table for requested protocol version */ 177 static Idtab * 178 idtab_lookup(int version) 179 { 180 if (version < 1 || version > 2) 181 fatal("internal error, bad protocol version %d", version); 182 return &idtable[version]; 183 } 184 185 static void 186 free_identity(Identity *id) 187 { 188 sshkey_free(id->key); 189 free(id->provider); 190 free(id->comment); 191 free(id); 192 } 193 194 /* return matching private key for given public key */ 195 static Identity * 196 lookup_identity(struct sshkey *key, int version) 197 { 198 Identity *id; 199 200 Idtab *tab = idtab_lookup(version); 201 TAILQ_FOREACH(id, &tab->idlist, next) { 202 if (sshkey_equal(key, id->key)) 203 return (id); 204 } 205 return (NULL); 206 } 207 208 /* Check confirmation of keysign request */ 209 static int 210 confirm_key(Identity *id) 211 { 212 char *p; 213 int ret = -1; 214 215 p = sshkey_fingerprint(id->key, fingerprint_hash, SSH_FP_DEFAULT); 216 if (p != NULL && 217 ask_permission("Allow use of key %s?\nKey fingerprint %s.", 218 id->comment, p)) 219 ret = 0; 220 free(p); 221 222 return (ret); 223 } 224 225 static void 226 send_status(SocketEntry *e, int success) 227 { 228 int r; 229 230 if ((r = sshbuf_put_u32(e->output, 1)) != 0 || 231 (r = sshbuf_put_u8(e->output, success ? 232 SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0) 233 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 234 } 235 236 /* send list of supported public keys to 'client' */ 237 static void 238 process_request_identities(SocketEntry *e, int version) 239 { 240 Idtab *tab = idtab_lookup(version); 241 Identity *id; 242 struct sshbuf *msg; 243 int r; 244 245 if ((msg = sshbuf_new()) == NULL) 246 fatal("%s: sshbuf_new failed", __func__); 247 if ((r = sshbuf_put_u8(msg, (version == 1) ? 248 SSH_AGENT_RSA_IDENTITIES_ANSWER : 249 SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 250 (r = sshbuf_put_u32(msg, tab->nentries)) != 0) 251 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 252 TAILQ_FOREACH(id, &tab->idlist, next) { 253 if (id->key->type == KEY_RSA1) { 254 #ifdef WITH_SSH1 255 if ((r = sshbuf_put_u32(msg, 256 BN_num_bits(id->key->rsa->n))) != 0 || 257 (r = sshbuf_put_bignum1(msg, 258 id->key->rsa->e)) != 0 || 259 (r = sshbuf_put_bignum1(msg, 260 id->key->rsa->n)) != 0) 261 fatal("%s: buffer error: %s", 262 __func__, ssh_err(r)); 263 #endif 264 } else { 265 u_char *blob; 266 size_t blen; 267 268 if ((r = sshkey_to_blob(id->key, &blob, &blen)) != 0) { 269 error("%s: sshkey_to_blob: %s", __func__, 270 ssh_err(r)); 271 continue; 272 } 273 if ((r = sshbuf_put_string(msg, blob, blen)) != 0) 274 fatal("%s: buffer error: %s", 275 __func__, ssh_err(r)); 276 free(blob); 277 } 278 if ((r = sshbuf_put_cstring(msg, id->comment)) != 0) 279 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 280 } 281 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 282 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 283 sshbuf_free(msg); 284 } 285 286 #ifdef WITH_SSH1 287 /* ssh1 only */ 288 static void 289 process_authentication_challenge1(SocketEntry *e) 290 { 291 u_char buf[32], mdbuf[16], session_id[16]; 292 u_int response_type; 293 BIGNUM *challenge; 294 Identity *id; 295 int r, len; 296 struct sshbuf *msg; 297 struct ssh_digest_ctx *md; 298 struct sshkey *key; 299 300 if ((msg = sshbuf_new()) == NULL) 301 fatal("%s: sshbuf_new failed", __func__); 302 if ((key = sshkey_new(KEY_RSA1)) == NULL) 303 fatal("%s: sshkey_new failed", __func__); 304 if ((challenge = BN_new()) == NULL) 305 fatal("%s: BN_new failed", __func__); 306 307 if ((r = sshbuf_get_u32(e->request, NULL)) != 0 || /* ignored */ 308 (r = sshbuf_get_bignum1(e->request, key->rsa->e)) != 0 || 309 (r = sshbuf_get_bignum1(e->request, key->rsa->n)) != 0 || 310 (r = sshbuf_get_bignum1(e->request, challenge))) 311 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 312 313 /* Only protocol 1.1 is supported */ 314 if (sshbuf_len(e->request) == 0) 315 goto failure; 316 if ((r = sshbuf_get(e->request, session_id, sizeof(session_id))) != 0 || 317 (r = sshbuf_get_u32(e->request, &response_type)) != 0) 318 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 319 if (response_type != 1) 320 goto failure; 321 322 id = lookup_identity(key, 1); 323 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) { 324 struct sshkey *private = id->key; 325 /* Decrypt the challenge using the private key. */ 326 if ((r = rsa_private_decrypt(challenge, challenge, 327 private->rsa) != 0)) { 328 fatal("%s: rsa_public_encrypt: %s", __func__, 329 ssh_err(r)); 330 goto failure; /* XXX ? */ 331 } 332 333 /* The response is MD5 of decrypted challenge plus session id */ 334 len = BN_num_bytes(challenge); 335 if (len <= 0 || len > 32) { 336 logit("%s: bad challenge length %d", __func__, len); 337 goto failure; 338 } 339 memset(buf, 0, 32); 340 BN_bn2bin(challenge, buf + 32 - len); 341 if ((md = ssh_digest_start(SSH_DIGEST_MD5)) == NULL || 342 ssh_digest_update(md, buf, 32) < 0 || 343 ssh_digest_update(md, session_id, 16) < 0 || 344 ssh_digest_final(md, mdbuf, sizeof(mdbuf)) < 0) 345 fatal("%s: md5 failed", __func__); 346 ssh_digest_free(md); 347 348 /* Send the response. */ 349 if ((r = sshbuf_put_u8(msg, SSH_AGENT_RSA_RESPONSE)) != 0 || 350 (r = sshbuf_put(msg, mdbuf, sizeof(mdbuf))) != 0) 351 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 352 goto send; 353 } 354 355 failure: 356 /* Unknown identity or protocol error. Send failure. */ 357 if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0) 358 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 359 send: 360 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 361 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 362 sshkey_free(key); 363 BN_clear_free(challenge); 364 sshbuf_free(msg); 365 } 366 #endif 367 368 static const char * 369 agent_decode_alg(struct sshkey *key, u_int flags) 370 { 371 if (key->type == KEY_RSA) { 372 if (flags & SSH_AGENT_RSA_SHA2_256) 373 return "rsa-sha2-256"; 374 else if (flags & SSH_AGENT_RSA_SHA2_512) 375 return "rsa-sha2-512"; 376 } 377 return NULL; 378 } 379 380 /* ssh2 only */ 381 static void 382 process_sign_request2(SocketEntry *e) 383 { 384 u_char *blob, *data, *signature = NULL; 385 size_t blen, dlen, slen = 0; 386 u_int compat = 0, flags; 387 int r, ok = -1; 388 struct sshbuf *msg; 389 struct sshkey *key; 390 struct identity *id; 391 392 if ((msg = sshbuf_new()) == NULL) 393 fatal("%s: sshbuf_new failed", __func__); 394 if ((r = sshbuf_get_string(e->request, &blob, &blen)) != 0 || 395 (r = sshbuf_get_string(e->request, &data, &dlen)) != 0 || 396 (r = sshbuf_get_u32(e->request, &flags)) != 0) 397 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 398 if (flags & SSH_AGENT_OLD_SIGNATURE) 399 compat = SSH_BUG_SIGBLOB; 400 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) { 401 error("%s: cannot parse key blob: %s", __func__, ssh_err(r)); 402 goto send; 403 } 404 if ((id = lookup_identity(key, 2)) == NULL) { 405 verbose("%s: %s key not found", __func__, sshkey_type(key)); 406 goto send; 407 } 408 if (id->confirm && confirm_key(id) != 0) { 409 verbose("%s: user refused key", __func__); 410 goto send; 411 } 412 if ((r = sshkey_sign(id->key, &signature, &slen, 413 data, dlen, agent_decode_alg(key, flags), compat)) != 0) { 414 error("%s: sshkey_sign: %s", __func__, ssh_err(r)); 415 goto send; 416 } 417 /* Success */ 418 ok = 0; 419 send: 420 sshkey_free(key); 421 if (ok == 0) { 422 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 || 423 (r = sshbuf_put_string(msg, signature, slen)) != 0) 424 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 425 } else if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0) 426 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 427 428 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 429 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 430 431 sshbuf_free(msg); 432 free(data); 433 free(blob); 434 free(signature); 435 } 436 437 /* shared */ 438 static void 439 process_remove_identity(SocketEntry *e, int version) 440 { 441 size_t blen; 442 int r, success = 0; 443 struct sshkey *key = NULL; 444 u_char *blob; 445 #ifdef WITH_SSH1 446 u_int bits; 447 #endif /* WITH_SSH1 */ 448 449 switch (version) { 450 #ifdef WITH_SSH1 451 case 1: 452 if ((key = sshkey_new(KEY_RSA1)) == NULL) { 453 error("%s: sshkey_new failed", __func__); 454 return; 455 } 456 if ((r = sshbuf_get_u32(e->request, &bits)) != 0 || 457 (r = sshbuf_get_bignum1(e->request, key->rsa->e)) != 0 || 458 (r = sshbuf_get_bignum1(e->request, key->rsa->n)) != 0) 459 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 460 461 if (bits != sshkey_size(key)) 462 logit("Warning: identity keysize mismatch: " 463 "actual %u, announced %u", 464 sshkey_size(key), bits); 465 break; 466 #endif /* WITH_SSH1 */ 467 case 2: 468 if ((r = sshbuf_get_string(e->request, &blob, &blen)) != 0) 469 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 470 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) 471 error("%s: sshkey_from_blob failed: %s", 472 __func__, ssh_err(r)); 473 free(blob); 474 break; 475 } 476 if (key != NULL) { 477 Identity *id = lookup_identity(key, version); 478 if (id != NULL) { 479 /* 480 * We have this key. Free the old key. Since we 481 * don't want to leave empty slots in the middle of 482 * the array, we actually free the key there and move 483 * all the entries between the empty slot and the end 484 * of the array. 485 */ 486 Idtab *tab = idtab_lookup(version); 487 if (tab->nentries < 1) 488 fatal("process_remove_identity: " 489 "internal error: tab->nentries %d", 490 tab->nentries); 491 TAILQ_REMOVE(&tab->idlist, id, next); 492 free_identity(id); 493 tab->nentries--; 494 success = 1; 495 } 496 sshkey_free(key); 497 } 498 send_status(e, success); 499 } 500 501 static void 502 process_remove_all_identities(SocketEntry *e, int version) 503 { 504 Idtab *tab = idtab_lookup(version); 505 Identity *id; 506 507 /* Loop over all identities and clear the keys. */ 508 while ((id = TAILQ_FIRST(&tab->idlist)) != NULL) { 509 TAILQ_REMOVE(&tab->idlist, id, next); 510 free_identity(id); 511 } 512 513 /* Mark that there are no identities. */ 514 tab->nentries = 0; 515 516 /* Send success. */ 517 send_status(e, 1); 518 } 519 520 /* removes expired keys and returns number of seconds until the next expiry */ 521 static time_t 522 reaper(void) 523 { 524 time_t deadline = 0, now = monotime(); 525 Identity *id, *nxt; 526 int version; 527 Idtab *tab; 528 529 for (version = 1; version < 3; version++) { 530 tab = idtab_lookup(version); 531 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 532 nxt = TAILQ_NEXT(id, next); 533 if (id->death == 0) 534 continue; 535 if (now >= id->death) { 536 debug("expiring key '%s'", id->comment); 537 TAILQ_REMOVE(&tab->idlist, id, next); 538 free_identity(id); 539 tab->nentries--; 540 } else 541 deadline = (deadline == 0) ? id->death : 542 MINIMUM(deadline, id->death); 543 } 544 } 545 if (deadline == 0 || deadline <= now) 546 return 0; 547 else 548 return (deadline - now); 549 } 550 551 /* 552 * XXX this and the corresponding serialisation function probably belongs 553 * in key.c 554 */ 555 #ifdef WITH_SSH1 556 static int 557 agent_decode_rsa1(struct sshbuf *m, struct sshkey **kp) 558 { 559 struct sshkey *k = NULL; 560 int r = SSH_ERR_INTERNAL_ERROR; 561 562 *kp = NULL; 563 if ((k = sshkey_new_private(KEY_RSA1)) == NULL) 564 return SSH_ERR_ALLOC_FAIL; 565 566 if ((r = sshbuf_get_u32(m, NULL)) != 0 || /* ignored */ 567 (r = sshbuf_get_bignum1(m, k->rsa->n)) != 0 || 568 (r = sshbuf_get_bignum1(m, k->rsa->e)) != 0 || 569 (r = sshbuf_get_bignum1(m, k->rsa->d)) != 0 || 570 (r = sshbuf_get_bignum1(m, k->rsa->iqmp)) != 0 || 571 /* SSH1 and SSL have p and q swapped */ 572 (r = sshbuf_get_bignum1(m, k->rsa->q)) != 0 || /* p */ 573 (r = sshbuf_get_bignum1(m, k->rsa->p)) != 0) /* q */ 574 goto out; 575 576 /* Generate additional parameters */ 577 if ((r = rsa_generate_additional_parameters(k->rsa)) != 0) 578 goto out; 579 /* enable blinding */ 580 if (RSA_blinding_on(k->rsa, NULL) != 1) { 581 r = SSH_ERR_LIBCRYPTO_ERROR; 582 goto out; 583 } 584 585 r = 0; /* success */ 586 out: 587 if (r == 0) 588 *kp = k; 589 else 590 sshkey_free(k); 591 return r; 592 } 593 #endif /* WITH_SSH1 */ 594 595 static void 596 process_add_identity(SocketEntry *e, int version) 597 { 598 Idtab *tab = idtab_lookup(version); 599 Identity *id; 600 int success = 0, confirm = 0; 601 u_int seconds; 602 char *comment = NULL; 603 time_t death = 0; 604 struct sshkey *k = NULL; 605 u_char ctype; 606 int r = SSH_ERR_INTERNAL_ERROR; 607 608 switch (version) { 609 #ifdef WITH_SSH1 610 case 1: 611 r = agent_decode_rsa1(e->request, &k); 612 break; 613 #endif /* WITH_SSH1 */ 614 case 2: 615 r = sshkey_private_deserialize(e->request, &k); 616 break; 617 } 618 if (r != 0 || k == NULL || 619 (r = sshbuf_get_cstring(e->request, &comment, NULL)) != 0) { 620 error("%s: decode private key: %s", __func__, ssh_err(r)); 621 goto err; 622 } 623 624 while (sshbuf_len(e->request)) { 625 if ((r = sshbuf_get_u8(e->request, &ctype)) != 0) { 626 error("%s: buffer error: %s", __func__, ssh_err(r)); 627 goto err; 628 } 629 switch (ctype) { 630 case SSH_AGENT_CONSTRAIN_LIFETIME: 631 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) { 632 error("%s: bad lifetime constraint: %s", 633 __func__, ssh_err(r)); 634 goto err; 635 } 636 death = monotime() + seconds; 637 break; 638 case SSH_AGENT_CONSTRAIN_CONFIRM: 639 confirm = 1; 640 break; 641 default: 642 error("%s: Unknown constraint %d", __func__, ctype); 643 err: 644 sshbuf_reset(e->request); 645 free(comment); 646 sshkey_free(k); 647 goto send; 648 } 649 } 650 651 success = 1; 652 if (lifetime && !death) 653 death = monotime() + lifetime; 654 if ((id = lookup_identity(k, version)) == NULL) { 655 id = xcalloc(1, sizeof(Identity)); 656 id->key = k; 657 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 658 /* Increment the number of identities. */ 659 tab->nentries++; 660 } else { 661 sshkey_free(k); 662 free(id->comment); 663 } 664 id->comment = comment; 665 id->death = death; 666 id->confirm = confirm; 667 send: 668 send_status(e, success); 669 } 670 671 /* XXX todo: encrypt sensitive data with passphrase */ 672 static void 673 process_lock_agent(SocketEntry *e, int lock) 674 { 675 int r, success = 0, delay; 676 char *passwd; 677 u_char passwdhash[LOCK_SIZE]; 678 static u_int fail_count = 0; 679 size_t pwlen; 680 681 if ((r = sshbuf_get_cstring(e->request, &passwd, &pwlen)) != 0) 682 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 683 if (pwlen == 0) { 684 debug("empty password not supported"); 685 } else if (locked && !lock) { 686 if (bcrypt_pbkdf(passwd, pwlen, (uint8_t *)lock_salt, sizeof(lock_salt), 687 (uint8_t *)passwdhash, sizeof(passwdhash), LOCK_ROUNDS) < 0) 688 fatal("bcrypt_pbkdf"); 689 if (timingsafe_bcmp(passwdhash, lock_pwhash, LOCK_SIZE) == 0) { 690 debug("agent unlocked"); 691 locked = 0; 692 fail_count = 0; 693 explicit_bzero(lock_pwhash, sizeof(lock_pwhash)); 694 success = 1; 695 } else { 696 /* delay in 0.1s increments up to 10s */ 697 if (fail_count < 100) 698 fail_count++; 699 delay = 100000 * fail_count; 700 debug("unlock failed, delaying %0.1lf seconds", 701 (double)delay/1000000); 702 usleep(delay); 703 } 704 explicit_bzero(passwdhash, sizeof(passwdhash)); 705 } else if (!locked && lock) { 706 debug("agent locked"); 707 locked = 1; 708 arc4random_buf(lock_salt, sizeof(lock_salt)); 709 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 710 lock_pwhash, sizeof(lock_pwhash), LOCK_ROUNDS) < 0) 711 fatal("bcrypt_pbkdf"); 712 success = 1; 713 } 714 explicit_bzero(passwd, pwlen); 715 free(passwd); 716 send_status(e, success); 717 } 718 719 static void 720 no_identities(SocketEntry *e, u_int type) 721 { 722 struct sshbuf *msg; 723 int r; 724 725 if ((msg = sshbuf_new()) == NULL) 726 fatal("%s: sshbuf_new failed", __func__); 727 if ((r = sshbuf_put_u8(msg, 728 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ? 729 SSH_AGENT_RSA_IDENTITIES_ANSWER : 730 SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 731 (r = sshbuf_put_u32(msg, 0)) != 0 || 732 (r = sshbuf_put_stringb(e->output, msg)) != 0) 733 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 734 sshbuf_free(msg); 735 } 736 737 #ifdef ENABLE_PKCS11 738 static void 739 process_add_smartcard_key(SocketEntry *e) 740 { 741 char *provider = NULL, *pin, canonical_provider[PATH_MAX]; 742 int r, i, version, count = 0, success = 0, confirm = 0; 743 u_int seconds; 744 time_t death = 0; 745 u_char type; 746 struct sshkey **keys = NULL, *k; 747 Identity *id; 748 Idtab *tab; 749 750 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 751 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) 752 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 753 754 while (sshbuf_len(e->request)) { 755 if ((r = sshbuf_get_u8(e->request, &type)) != 0) 756 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 757 switch (type) { 758 case SSH_AGENT_CONSTRAIN_LIFETIME: 759 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) 760 fatal("%s: buffer error: %s", 761 __func__, ssh_err(r)); 762 death = monotime() + seconds; 763 break; 764 case SSH_AGENT_CONSTRAIN_CONFIRM: 765 confirm = 1; 766 break; 767 default: 768 error("process_add_smartcard_key: " 769 "Unknown constraint type %d", type); 770 goto send; 771 } 772 } 773 if (realpath(provider, canonical_provider) == NULL) { 774 verbose("failed PKCS#11 add of \"%.100s\": realpath: %s", 775 provider, strerror(errno)); 776 goto send; 777 } 778 if (match_pattern_list(canonical_provider, pkcs11_whitelist, 0) != 1) { 779 verbose("refusing PKCS#11 add of \"%.100s\": " 780 "provider not whitelisted", canonical_provider); 781 goto send; 782 } 783 debug("%s: add %.100s", __func__, canonical_provider); 784 if (lifetime && !death) 785 death = monotime() + lifetime; 786 787 count = pkcs11_add_provider(canonical_provider, pin, &keys); 788 for (i = 0; i < count; i++) { 789 k = keys[i]; 790 version = k->type == KEY_RSA1 ? 1 : 2; 791 tab = idtab_lookup(version); 792 if (lookup_identity(k, version) == NULL) { 793 id = xcalloc(1, sizeof(Identity)); 794 id->key = k; 795 id->provider = xstrdup(canonical_provider); 796 id->comment = xstrdup(canonical_provider); /* XXX */ 797 id->death = death; 798 id->confirm = confirm; 799 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 800 tab->nentries++; 801 success = 1; 802 } else { 803 sshkey_free(k); 804 } 805 keys[i] = NULL; 806 } 807 send: 808 free(pin); 809 free(provider); 810 free(keys); 811 send_status(e, success); 812 } 813 814 static void 815 process_remove_smartcard_key(SocketEntry *e) 816 { 817 char *provider = NULL, *pin = NULL; 818 int r, version, success = 0; 819 Identity *id, *nxt; 820 Idtab *tab; 821 822 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 823 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) 824 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 825 free(pin); 826 827 for (version = 1; version < 3; version++) { 828 tab = idtab_lookup(version); 829 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 830 nxt = TAILQ_NEXT(id, next); 831 /* Skip file--based keys */ 832 if (id->provider == NULL) 833 continue; 834 if (!strcmp(provider, id->provider)) { 835 TAILQ_REMOVE(&tab->idlist, id, next); 836 free_identity(id); 837 tab->nentries--; 838 } 839 } 840 } 841 if (pkcs11_del_provider(provider) == 0) 842 success = 1; 843 else 844 error("process_remove_smartcard_key:" 845 " pkcs11_del_provider failed"); 846 free(provider); 847 send_status(e, success); 848 } 849 #endif /* ENABLE_PKCS11 */ 850 851 /* dispatch incoming messages */ 852 853 static void 854 process_message(SocketEntry *e) 855 { 856 u_int msg_len; 857 u_char type; 858 const u_char *cp; 859 int r; 860 861 if (sshbuf_len(e->input) < 5) 862 return; /* Incomplete message. */ 863 cp = sshbuf_ptr(e->input); 864 msg_len = PEEK_U32(cp); 865 if (msg_len > 256 * 1024) { 866 close_socket(e); 867 return; 868 } 869 if (sshbuf_len(e->input) < msg_len + 4) 870 return; 871 872 /* move the current input to e->request */ 873 sshbuf_reset(e->request); 874 if ((r = sshbuf_get_stringb(e->input, e->request)) != 0 || 875 (r = sshbuf_get_u8(e->request, &type)) != 0) 876 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 877 878 /* check wheter agent is locked */ 879 if (locked && type != SSH_AGENTC_UNLOCK) { 880 sshbuf_reset(e->request); 881 switch (type) { 882 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 883 case SSH2_AGENTC_REQUEST_IDENTITIES: 884 /* send empty lists */ 885 no_identities(e, type); 886 break; 887 default: 888 /* send a fail message for all other request types */ 889 send_status(e, 0); 890 } 891 return; 892 } 893 894 debug("type %d", type); 895 switch (type) { 896 case SSH_AGENTC_LOCK: 897 case SSH_AGENTC_UNLOCK: 898 process_lock_agent(e, type == SSH_AGENTC_LOCK); 899 break; 900 #ifdef WITH_SSH1 901 /* ssh1 */ 902 case SSH_AGENTC_RSA_CHALLENGE: 903 process_authentication_challenge1(e); 904 break; 905 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 906 process_request_identities(e, 1); 907 break; 908 case SSH_AGENTC_ADD_RSA_IDENTITY: 909 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 910 process_add_identity(e, 1); 911 break; 912 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 913 process_remove_identity(e, 1); 914 break; 915 #endif 916 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 917 process_remove_all_identities(e, 1); /* safe for !WITH_SSH1 */ 918 break; 919 /* ssh2 */ 920 case SSH2_AGENTC_SIGN_REQUEST: 921 process_sign_request2(e); 922 break; 923 case SSH2_AGENTC_REQUEST_IDENTITIES: 924 process_request_identities(e, 2); 925 break; 926 case SSH2_AGENTC_ADD_IDENTITY: 927 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 928 process_add_identity(e, 2); 929 break; 930 case SSH2_AGENTC_REMOVE_IDENTITY: 931 process_remove_identity(e, 2); 932 break; 933 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 934 process_remove_all_identities(e, 2); 935 break; 936 #ifdef ENABLE_PKCS11 937 case SSH_AGENTC_ADD_SMARTCARD_KEY: 938 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 939 process_add_smartcard_key(e); 940 break; 941 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 942 process_remove_smartcard_key(e); 943 break; 944 #endif /* ENABLE_PKCS11 */ 945 default: 946 /* Unknown message. Respond with failure. */ 947 error("Unknown message %d", type); 948 sshbuf_reset(e->request); 949 send_status(e, 0); 950 break; 951 } 952 } 953 954 static void 955 new_socket(sock_type type, int fd) 956 { 957 u_int i, old_alloc, new_alloc; 958 959 set_nonblock(fd); 960 961 if (fd > max_fd) 962 max_fd = fd; 963 964 for (i = 0; i < sockets_alloc; i++) 965 if (sockets[i].type == AUTH_UNUSED) { 966 sockets[i].fd = fd; 967 if ((sockets[i].input = sshbuf_new()) == NULL) 968 fatal("%s: sshbuf_new failed", __func__); 969 if ((sockets[i].output = sshbuf_new()) == NULL) 970 fatal("%s: sshbuf_new failed", __func__); 971 if ((sockets[i].request = sshbuf_new()) == NULL) 972 fatal("%s: sshbuf_new failed", __func__); 973 sockets[i].type = type; 974 return; 975 } 976 old_alloc = sockets_alloc; 977 new_alloc = sockets_alloc + 10; 978 sockets = xreallocarray(sockets, new_alloc, sizeof(sockets[0])); 979 for (i = old_alloc; i < new_alloc; i++) 980 sockets[i].type = AUTH_UNUSED; 981 sockets_alloc = new_alloc; 982 sockets[old_alloc].fd = fd; 983 if ((sockets[old_alloc].input = sshbuf_new()) == NULL) 984 fatal("%s: sshbuf_new failed", __func__); 985 if ((sockets[old_alloc].output = sshbuf_new()) == NULL) 986 fatal("%s: sshbuf_new failed", __func__); 987 if ((sockets[old_alloc].request = sshbuf_new()) == NULL) 988 fatal("%s: sshbuf_new failed", __func__); 989 sockets[old_alloc].type = type; 990 } 991 992 static int 993 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp, 994 struct timeval **tvpp) 995 { 996 u_int i, sz; 997 int n = 0; 998 static struct timeval tv; 999 time_t deadline; 1000 1001 for (i = 0; i < sockets_alloc; i++) { 1002 switch (sockets[i].type) { 1003 case AUTH_SOCKET: 1004 case AUTH_CONNECTION: 1005 n = MAXIMUM(n, sockets[i].fd); 1006 break; 1007 case AUTH_UNUSED: 1008 break; 1009 default: 1010 fatal("Unknown socket type %d", sockets[i].type); 1011 break; 1012 } 1013 } 1014 1015 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 1016 if (*fdrp == NULL || sz > *nallocp) { 1017 free(*fdrp); 1018 free(*fdwp); 1019 *fdrp = xmalloc(sz); 1020 *fdwp = xmalloc(sz); 1021 *nallocp = sz; 1022 } 1023 if (n < *fdl) 1024 debug("XXX shrink: %d < %d", n, *fdl); 1025 *fdl = n; 1026 memset(*fdrp, 0, sz); 1027 memset(*fdwp, 0, sz); 1028 1029 for (i = 0; i < sockets_alloc; i++) { 1030 switch (sockets[i].type) { 1031 case AUTH_SOCKET: 1032 case AUTH_CONNECTION: 1033 FD_SET(sockets[i].fd, *fdrp); 1034 if (sshbuf_len(sockets[i].output) > 0) 1035 FD_SET(sockets[i].fd, *fdwp); 1036 break; 1037 default: 1038 break; 1039 } 1040 } 1041 deadline = reaper(); 1042 if (parent_alive_interval != 0) 1043 deadline = (deadline == 0) ? parent_alive_interval : 1044 MINIMUM(deadline, parent_alive_interval); 1045 if (deadline == 0) { 1046 *tvpp = NULL; 1047 } else { 1048 tv.tv_sec = deadline; 1049 tv.tv_usec = 0; 1050 *tvpp = &tv; 1051 } 1052 return (1); 1053 } 1054 1055 static void 1056 after_select(fd_set *readset, fd_set *writeset) 1057 { 1058 struct sockaddr_un sunaddr; 1059 socklen_t slen; 1060 char buf[1024]; 1061 int len, sock, r; 1062 u_int i, orig_alloc; 1063 uid_t euid; 1064 gid_t egid; 1065 1066 for (i = 0, orig_alloc = sockets_alloc; i < orig_alloc; i++) 1067 switch (sockets[i].type) { 1068 case AUTH_UNUSED: 1069 break; 1070 case AUTH_SOCKET: 1071 if (FD_ISSET(sockets[i].fd, readset)) { 1072 slen = sizeof(sunaddr); 1073 sock = accept(sockets[i].fd, 1074 (struct sockaddr *)&sunaddr, &slen); 1075 if (sock < 0) { 1076 error("accept from AUTH_SOCKET: %s", 1077 strerror(errno)); 1078 break; 1079 } 1080 if (getpeereid(sock, &euid, &egid) < 0) { 1081 error("getpeereid %d failed: %s", 1082 sock, strerror(errno)); 1083 close(sock); 1084 break; 1085 } 1086 if ((euid != 0) && (getuid() != euid)) { 1087 error("uid mismatch: " 1088 "peer euid %u != uid %u", 1089 (u_int) euid, (u_int) getuid()); 1090 close(sock); 1091 break; 1092 } 1093 new_socket(AUTH_CONNECTION, sock); 1094 } 1095 break; 1096 case AUTH_CONNECTION: 1097 if (sshbuf_len(sockets[i].output) > 0 && 1098 FD_ISSET(sockets[i].fd, writeset)) { 1099 len = write(sockets[i].fd, 1100 sshbuf_ptr(sockets[i].output), 1101 sshbuf_len(sockets[i].output)); 1102 if (len == -1 && (errno == EAGAIN || 1103 errno == EINTR)) 1104 continue; 1105 if (len <= 0) { 1106 close_socket(&sockets[i]); 1107 break; 1108 } 1109 if ((r = sshbuf_consume(sockets[i].output, 1110 len)) != 0) 1111 fatal("%s: buffer error: %s", 1112 __func__, ssh_err(r)); 1113 } 1114 if (FD_ISSET(sockets[i].fd, readset)) { 1115 len = read(sockets[i].fd, buf, sizeof(buf)); 1116 if (len == -1 && (errno == EAGAIN || 1117 errno == EINTR)) 1118 continue; 1119 if (len <= 0) { 1120 close_socket(&sockets[i]); 1121 break; 1122 } 1123 if ((r = sshbuf_put(sockets[i].input, 1124 buf, len)) != 0) 1125 fatal("%s: buffer error: %s", 1126 __func__, ssh_err(r)); 1127 explicit_bzero(buf, sizeof(buf)); 1128 process_message(&sockets[i]); 1129 } 1130 break; 1131 default: 1132 fatal("Unknown type %d", sockets[i].type); 1133 } 1134 } 1135 1136 static void 1137 cleanup_socket(void) 1138 { 1139 if (cleanup_pid != 0 && getpid() != cleanup_pid) 1140 return; 1141 debug("%s: cleanup", __func__); 1142 if (socket_name[0]) 1143 unlink(socket_name); 1144 if (socket_dir[0]) 1145 rmdir(socket_dir); 1146 } 1147 1148 void 1149 cleanup_exit(int i) 1150 { 1151 cleanup_socket(); 1152 _exit(i); 1153 } 1154 1155 /*ARGSUSED*/ 1156 __dead static void 1157 cleanup_handler(int sig) 1158 { 1159 cleanup_socket(); 1160 #ifdef ENABLE_PKCS11 1161 pkcs11_terminate(); 1162 #endif 1163 _exit(2); 1164 } 1165 1166 static void 1167 check_parent_exists(void) 1168 { 1169 /* 1170 * If our parent has exited then getppid() will return (pid_t)1, 1171 * so testing for that should be safe. 1172 */ 1173 if (parent_pid != -1 && getppid() != parent_pid) { 1174 /* printf("Parent has died - Authentication agent exiting.\n"); */ 1175 cleanup_socket(); 1176 _exit(2); 1177 } 1178 } 1179 1180 __dead static void 1181 usage(void) 1182 { 1183 fprintf(stderr, 1184 "usage: ssh-agent [-c | -s] [-Dd] [-a bind_address] [-E fingerprint_hash]\n" 1185 " [-P pkcs11_whitelist] [-t life] [command [arg ...]]\n" 1186 " ssh-agent [-c | -s] -k\n"); 1187 exit(1); 1188 } 1189 1190 static void 1191 csh_setenv(const char *name, const char *value) 1192 { 1193 printf("setenv %s %s;\n", name, value); 1194 } 1195 1196 static void 1197 csh_unsetenv(const char *name) 1198 { 1199 printf("unsetenv %s;\n", name); 1200 } 1201 1202 static void 1203 sh_setenv(const char *name, const char *value) 1204 { 1205 printf("%s=%s; export %s;\n", name, value, name); 1206 } 1207 1208 static void 1209 sh_unsetenv(const char *name) 1210 { 1211 printf("unset %s;\n", name); 1212 } 1213 int 1214 main(int ac, char **av) 1215 { 1216 int c_flag = 0, d_flag = 0, D_flag = 0, k_flag = 0, s_flag = 0; 1217 int sock, fd, ch, result, saved_errno; 1218 u_int nalloc; 1219 char *shell, *pidstr, *agentsocket = NULL; 1220 fd_set *readsetp = NULL, *writesetp = NULL; 1221 struct rlimit rlim; 1222 extern int optind; 1223 extern char *optarg; 1224 pid_t pid; 1225 char pidstrbuf[1 + 3 * sizeof pid]; 1226 struct timeval *tvp = NULL; 1227 size_t len; 1228 mode_t prev_mask; 1229 void (*f_setenv)(const char *, const char *); 1230 void (*f_unsetenv)(const char *); 1231 1232 ssh_malloc_init(); /* must be called before any mallocs */ 1233 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1234 sanitise_stdfd(); 1235 1236 /* drop */ 1237 setegid(getgid()); 1238 setgid(getgid()); 1239 1240 #ifdef WITH_OPENSSL 1241 OpenSSL_add_all_algorithms(); 1242 #endif 1243 1244 while ((ch = getopt(ac, av, "cDdksE:a:P:t:")) != -1) { 1245 switch (ch) { 1246 case 'E': 1247 fingerprint_hash = ssh_digest_alg_by_name(optarg); 1248 if (fingerprint_hash == -1) 1249 fatal("Invalid hash algorithm \"%s\"", optarg); 1250 break; 1251 case 'c': 1252 if (s_flag) 1253 usage(); 1254 c_flag++; 1255 break; 1256 case 'k': 1257 k_flag++; 1258 break; 1259 case 'P': 1260 if (pkcs11_whitelist != NULL) 1261 fatal("-P option already specified"); 1262 pkcs11_whitelist = xstrdup(optarg); 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 default: 1289 usage(); 1290 } 1291 } 1292 ac -= optind; 1293 av += optind; 1294 1295 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag || D_flag)) 1296 usage(); 1297 1298 if (pkcs11_whitelist == NULL) 1299 pkcs11_whitelist = xstrdup(DEFAULT_PKCS11_WHITELIST); 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 (c_flag) { 1308 f_setenv = csh_setenv; 1309 f_unsetenv = csh_unsetenv; 1310 } else { 1311 f_setenv = sh_setenv; 1312 f_unsetenv = sh_unsetenv; 1313 } 1314 if (k_flag) { 1315 const char *errstr = NULL; 1316 1317 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1318 if (pidstr == NULL) { 1319 fprintf(stderr, "%s not set, cannot kill agent\n", 1320 SSH_AGENTPID_ENV_NAME); 1321 exit(1); 1322 } 1323 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr); 1324 if (errstr) { 1325 fprintf(stderr, 1326 "%s=\"%s\", which is not a good PID: %s\n", 1327 SSH_AGENTPID_ENV_NAME, pidstr, errstr); 1328 exit(1); 1329 } 1330 if (kill(pid, SIGTERM) == -1) { 1331 perror("kill"); 1332 exit(1); 1333 } 1334 (*f_unsetenv)(SSH_AUTHSOCKET_ENV_NAME); 1335 (*f_unsetenv)(SSH_AGENTPID_ENV_NAME); 1336 printf("echo Agent pid %ld killed;\n", (long)pid); 1337 exit(0); 1338 } 1339 parent_pid = getpid(); 1340 1341 if (agentsocket == NULL) { 1342 /* Create private directory for agent socket */ 1343 mktemp_proto(socket_dir, sizeof(socket_dir)); 1344 if (mkdtemp(socket_dir) == NULL) { 1345 perror("mkdtemp: private socket dir"); 1346 exit(1); 1347 } 1348 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1349 (long)parent_pid); 1350 } else { 1351 /* Try to use specified agent socket */ 1352 socket_dir[0] = '\0'; 1353 strlcpy(socket_name, agentsocket, sizeof socket_name); 1354 } 1355 1356 /* 1357 * Create socket early so it will exist before command gets run from 1358 * the parent. 1359 */ 1360 prev_mask = umask(0177); 1361 sock = unix_listener(socket_name, SSH_LISTEN_BACKLOG, 0); 1362 if (sock < 0) { 1363 /* XXX - unix_listener() calls error() not perror() */ 1364 *socket_name = '\0'; /* Don't unlink any existing file */ 1365 cleanup_exit(1); 1366 } 1367 umask(prev_mask); 1368 1369 /* 1370 * Fork, and have the parent execute the command, if any, or present 1371 * the socket data. The child continues as the authentication agent. 1372 */ 1373 if (D_flag || d_flag) { 1374 log_init(__progname, 1375 d_flag ? SYSLOG_LEVEL_DEBUG3 : SYSLOG_LEVEL_INFO, 1376 SYSLOG_FACILITY_AUTH, 1); 1377 if (c_flag) 1378 printf("setenv %s %s;\n", 1379 SSH_AUTHSOCKET_ENV_NAME, socket_name); 1380 else 1381 printf("%s=%s; export %s;\n", 1382 SSH_AUTHSOCKET_ENV_NAME, socket_name, 1383 SSH_AUTHSOCKET_ENV_NAME); 1384 printf("echo Agent pid %ld;\n", (long)parent_pid); 1385 fflush(stdout); 1386 goto skip; 1387 } 1388 pid = fork(); 1389 if (pid == -1) { 1390 perror("fork"); 1391 cleanup_exit(1); 1392 } 1393 if (pid != 0) { /* Parent - execute the given command. */ 1394 close(sock); 1395 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1396 if (ac == 0) { 1397 (*f_setenv)(SSH_AUTHSOCKET_ENV_NAME, socket_name); 1398 (*f_setenv)(SSH_AGENTPID_ENV_NAME, pidstrbuf); 1399 printf("echo Agent pid %ld;\n", (long)pid); 1400 exit(0); 1401 } 1402 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1403 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1404 perror("setenv"); 1405 exit(1); 1406 } 1407 execvp(av[0], av); 1408 perror(av[0]); 1409 exit(1); 1410 } 1411 /* child */ 1412 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1413 1414 if (setsid() == -1) { 1415 error("setsid: %s", strerror(errno)); 1416 cleanup_exit(1); 1417 } 1418 1419 (void)chdir("/"); 1420 1421 if (sock != STDERR_FILENO + 1) { 1422 if (dup2(sock, STDERR_FILENO + 1) == -1) { 1423 error("dup2: %s", strerror(errno)); 1424 cleanup_exit(1); 1425 } 1426 close(sock); 1427 sock = STDERR_FILENO + 1; 1428 } 1429 #if defined(F_CLOSEM) 1430 if (fcntl(sock + 1, F_CLOSEM, 0) == -1) { 1431 error("fcntl F_CLOSEM: %s", strerror(errno)); 1432 cleanup_exit(1); 1433 } 1434 #else 1435 { 1436 int nfiles; 1437 #if defined(_SC_OPEN_MAX) 1438 nfiles = sysconf(_SC_OPEN_MAX); 1439 #elif defined(RLIMIT_NOFILE) 1440 if (getrlimit(RLIMIT_CORE, &rlim) < 0) { 1441 error("getrlimit RLIMIT_NOFILE: %s", strerror(errno)); 1442 cleanup_exit(1); 1443 } 1444 nfiles = rlim.rlim_cur; 1445 #elif defined(OPEN_MAX) 1446 nfiles = OPEN_MAX; 1447 #elif defined(NOFILE) 1448 nfiles = NOFILE; 1449 #else 1450 nfiles = 1024; 1451 #endif 1452 for (fd = sock + 1; fd < nfiles; fd++) 1453 close(fd); 1454 } 1455 #endif 1456 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1457 if (dup2(fd, STDIN_FILENO) == -1 || 1458 dup2(fd, STDOUT_FILENO) == -1 || 1459 dup2(fd, STDERR_FILENO) == -1) { 1460 error("dup2: %s", strerror(errno)); 1461 cleanup_exit(1); 1462 } 1463 if (fd > STDERR_FILENO) 1464 close(fd); 1465 } 1466 1467 /* deny core dumps, since memory contains unencrypted private keys */ 1468 rlim.rlim_cur = rlim.rlim_max = 0; 1469 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 1470 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1471 cleanup_exit(1); 1472 } 1473 1474 skip: 1475 1476 cleanup_pid = getpid(); 1477 1478 #ifdef ENABLE_PKCS11 1479 pkcs11_init(0); 1480 #endif 1481 new_socket(AUTH_SOCKET, sock); 1482 if (ac > 0) 1483 parent_alive_interval = 10; 1484 idtab_init(); 1485 signal(SIGPIPE, SIG_IGN); 1486 signal(SIGINT, (d_flag | D_flag) ? cleanup_handler : SIG_IGN); 1487 signal(SIGHUP, cleanup_handler); 1488 signal(SIGTERM, cleanup_handler); 1489 nalloc = 0; 1490 1491 #ifdef __OpenBSD__ 1492 if (pledge("stdio rpath cpath unix id proc exec", NULL) == -1) 1493 fatal("%s: pledge: %s", __progname, strerror(errno)); 1494 #endif 1495 1496 while (1) { 1497 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp); 1498 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp); 1499 saved_errno = errno; 1500 if (parent_alive_interval != 0) 1501 check_parent_exists(); 1502 (void) reaper(); /* remove expired keys */ 1503 if (result < 0) { 1504 if (saved_errno == EINTR) 1505 continue; 1506 fatal("select: %s", strerror(saved_errno)); 1507 } else if (result > 0) 1508 after_select(readsetp, writesetp); 1509 } 1510 /* NOTREACHED */ 1511 } 1512