1 /* $NetBSD: ssh-agent.c,v 1.28 2020/02/27 00:24:40 christos Exp $ */ 2 /* $OpenBSD: ssh-agent.c,v 1.255 2020/02/06 22:30:54 naddy Exp $ */ 3 /* 4 * Author: Tatu Ylonen <ylo@cs.hut.fi> 5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 6 * All rights reserved 7 * The authentication agent program. 8 * 9 * As far as I am concerned, the code I have written for this software 10 * can be used freely for any purpose. Any derived versions of this 11 * software must be clearly marked as such, and if the derived work is 12 * incompatible with the protocol description in the RFC file, it must be 13 * called by a name other than "ssh" or "Secure Shell". 14 * 15 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions 19 * are met: 20 * 1. Redistributions of source code must retain the above copyright 21 * notice, this list of conditions and the following disclaimer. 22 * 2. Redistributions in binary form must reproduce the above copyright 23 * notice, this list of conditions and the following disclaimer in the 24 * documentation and/or other materials provided with the distribution. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 29 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 30 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 31 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 35 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 36 */ 37 38 #include "includes.h" 39 __RCSID("$NetBSD: ssh-agent.c,v 1.28 2020/02/27 00:24:40 christos Exp $"); 40 41 #include <sys/param.h> /* MIN MAX */ 42 #include <sys/types.h> 43 #include <sys/time.h> 44 #include <sys/queue.h> 45 #include <sys/resource.h> 46 #include <sys/socket.h> 47 #include <sys/stat.h> 48 #include <sys/un.h> 49 #include <sys/wait.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 <poll.h> 59 #include <signal.h> 60 #include <stdlib.h> 61 #include <stdio.h> 62 #include <string.h> 63 #include <stdarg.h> 64 #include <limits.h> 65 #include <time.h> 66 #include <unistd.h> 67 #include <util.h> 68 69 #include "xmalloc.h" 70 #include "ssh.h" 71 #include "sshbuf.h" 72 #include "sshkey.h" 73 #include "authfd.h" 74 #include "compat.h" 75 #include "log.h" 76 #include "misc.h" 77 #include "getpeereid.h" 78 #include "digest.h" 79 #include "ssherr.h" 80 #include "match.h" 81 #include "msg.h" 82 #include "ssherr.h" 83 #include "pathnames.h" 84 #include "ssh-pkcs11.h" 85 #include "sk-api.h" 86 87 #ifndef DEFAULT_PROVIDER_WHITELIST 88 # define DEFAULT_PROVIDER_WHITELIST "/usr/lib*/*,/usr/pkg/lib*/*" 89 #endif 90 91 /* Maximum accepted message length */ 92 #define AGENT_MAX_LEN (256*1024) 93 /* Maximum bytes to read from client socket */ 94 #define AGENT_RBUF_LEN (4096) 95 96 typedef enum { 97 AUTH_UNUSED, 98 AUTH_SOCKET, 99 AUTH_CONNECTION 100 } sock_type; 101 102 typedef struct { 103 int fd; 104 sock_type type; 105 struct sshbuf *input; 106 struct sshbuf *output; 107 struct sshbuf *request; 108 } SocketEntry; 109 110 u_int sockets_alloc = 0; 111 SocketEntry *sockets = NULL; 112 113 typedef struct identity { 114 TAILQ_ENTRY(identity) next; 115 struct sshkey *key; 116 char *comment; 117 char *provider; 118 time_t death; 119 u_int confirm; 120 char *sk_provider; 121 } Identity; 122 123 struct idtable { 124 int nentries; 125 TAILQ_HEAD(idqueue, identity) idlist; 126 }; 127 128 /* private key table */ 129 struct idtable *idtab; 130 131 int max_fd = 0; 132 133 /* pid of shell == parent of agent */ 134 pid_t parent_pid = -1; 135 time_t parent_alive_interval = 0; 136 137 /* pid of process for which cleanup_socket is applicable */ 138 pid_t cleanup_pid = 0; 139 140 /* pathname and directory for AUTH_SOCKET */ 141 char socket_name[PATH_MAX]; 142 char socket_dir[PATH_MAX]; 143 144 /* PKCS#11/Security key path whitelist */ 145 static char *provider_whitelist; 146 147 /* locking */ 148 #define LOCK_SIZE 32 149 #define LOCK_SALT_SIZE 16 150 #define LOCK_ROUNDS 1 151 int locked = 0; 152 u_char lock_pwhash[LOCK_SIZE]; 153 u_char lock_salt[LOCK_SALT_SIZE]; 154 155 extern char *__progname; 156 157 /* Default lifetime in seconds (0 == forever) */ 158 static long lifetime = 0; 159 160 static int fingerprint_hash = SSH_FP_HASH_DEFAULT; 161 162 static void 163 close_socket(SocketEntry *e) 164 { 165 close(e->fd); 166 e->fd = -1; 167 e->type = AUTH_UNUSED; 168 sshbuf_free(e->input); 169 sshbuf_free(e->output); 170 sshbuf_free(e->request); 171 } 172 173 static void 174 idtab_init(void) 175 { 176 idtab = xcalloc(1, sizeof(*idtab)); 177 TAILQ_INIT(&idtab->idlist); 178 idtab->nentries = 0; 179 } 180 181 static void 182 free_identity(Identity *id) 183 { 184 sshkey_free(id->key); 185 free(id->provider); 186 free(id->comment); 187 free(id->sk_provider); 188 free(id); 189 } 190 191 /* return matching private key for given public key */ 192 static Identity * 193 lookup_identity(struct sshkey *key) 194 { 195 Identity *id; 196 197 TAILQ_FOREACH(id, &idtab->idlist, next) { 198 if (sshkey_equal(key, id->key)) 199 return (id); 200 } 201 return (NULL); 202 } 203 204 /* Check confirmation of keysign request */ 205 static int 206 confirm_key(Identity *id) 207 { 208 char *p; 209 int ret = -1; 210 211 p = sshkey_fingerprint(id->key, fingerprint_hash, SSH_FP_DEFAULT); 212 if (p != NULL && 213 ask_permission("Allow use of key %s?\nKey fingerprint %s.", 214 id->comment, p)) 215 ret = 0; 216 free(p); 217 218 return (ret); 219 } 220 221 static void 222 send_status(SocketEntry *e, int success) 223 { 224 int r; 225 226 if ((r = sshbuf_put_u32(e->output, 1)) != 0 || 227 (r = sshbuf_put_u8(e->output, success ? 228 SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0) 229 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 230 } 231 232 /* send list of supported public keys to 'client' */ 233 static void 234 process_request_identities(SocketEntry *e) 235 { 236 Identity *id; 237 struct sshbuf *msg; 238 int r; 239 240 if ((msg = sshbuf_new()) == NULL) 241 fatal("%s: sshbuf_new failed", __func__); 242 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 243 (r = sshbuf_put_u32(msg, idtab->nentries)) != 0) 244 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 245 TAILQ_FOREACH(id, &idtab->idlist, next) { 246 if ((r = sshkey_puts_opts(id->key, msg, SSHKEY_SERIALIZE_INFO)) 247 != 0 || 248 (r = sshbuf_put_cstring(msg, id->comment)) != 0) { 249 error("%s: put key/comment: %s", __func__, 250 ssh_err(r)); 251 continue; 252 } 253 } 254 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 255 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 256 sshbuf_free(msg); 257 } 258 259 260 static const char * 261 agent_decode_alg(struct sshkey *key, u_int flags) 262 { 263 if (key->type == KEY_RSA) { 264 if (flags & SSH_AGENT_RSA_SHA2_256) 265 return "rsa-sha2-256"; 266 else if (flags & SSH_AGENT_RSA_SHA2_512) 267 return "rsa-sha2-512"; 268 } else if (key->type == KEY_RSA_CERT) { 269 if (flags & SSH_AGENT_RSA_SHA2_256) 270 return "rsa-sha2-256-cert-v01@openssh.com"; 271 else if (flags & SSH_AGENT_RSA_SHA2_512) 272 return "rsa-sha2-512-cert-v01@openssh.com"; 273 } 274 return NULL; 275 } 276 277 /* ssh2 only */ 278 static void 279 process_sign_request2(SocketEntry *e) 280 { 281 const u_char *data; 282 u_char *signature = NULL; 283 size_t dlen, slen = 0; 284 u_int compat = 0, flags; 285 int r, ok = -1; 286 char *fp = NULL; 287 struct sshbuf *msg; 288 struct sshkey *key = NULL; 289 struct identity *id; 290 struct notifier_ctx *notifier = NULL; 291 292 if ((msg = sshbuf_new()) == NULL) 293 fatal("%s: sshbuf_new failed", __func__); 294 if ((r = sshkey_froms(e->request, &key)) != 0 || 295 (r = sshbuf_get_string_direct(e->request, &data, &dlen)) != 0 || 296 (r = sshbuf_get_u32(e->request, &flags)) != 0) { 297 error("%s: couldn't parse request: %s", __func__, ssh_err(r)); 298 goto send; 299 } 300 301 if ((id = lookup_identity(key)) == NULL) { 302 verbose("%s: %s key not found", __func__, sshkey_type(key)); 303 goto send; 304 } 305 if (id->confirm && confirm_key(id) != 0) { 306 verbose("%s: user refused key", __func__); 307 goto send; 308 } 309 if (sshkey_is_sk(id->key) && 310 (id->key->sk_flags & SSH_SK_USER_PRESENCE_REQD)) { 311 if ((fp = sshkey_fingerprint(key, SSH_FP_HASH_DEFAULT, 312 SSH_FP_DEFAULT)) == NULL) 313 fatal("%s: fingerprint failed", __func__); 314 notifier = notify_start(0, 315 "Confirm user presence for key %s %s", 316 sshkey_type(id->key), fp); 317 } 318 if ((r = sshkey_sign(id->key, &signature, &slen, 319 data, dlen, agent_decode_alg(key, flags), 320 id->sk_provider, compat)) != 0) { 321 error("%s: sshkey_sign: %s", __func__, ssh_err(r)); 322 goto send; 323 } 324 /* Success */ 325 ok = 0; 326 send: 327 notify_complete(notifier); 328 sshkey_free(key); 329 free(fp); 330 if (ok == 0) { 331 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 || 332 (r = sshbuf_put_string(msg, signature, slen)) != 0) 333 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 334 } else if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0) 335 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 336 337 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 338 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 339 340 sshbuf_free(msg); 341 free(signature); 342 } 343 344 /* shared */ 345 static void 346 process_remove_identity(SocketEntry *e) 347 { 348 int r, success = 0; 349 struct sshkey *key = NULL; 350 Identity *id; 351 352 if ((r = sshkey_froms(e->request, &key)) != 0) { 353 error("%s: get key: %s", __func__, ssh_err(r)); 354 goto done; 355 } 356 if ((id = lookup_identity(key)) == NULL) { 357 debug("%s: key not found", __func__); 358 goto done; 359 } 360 /* We have this key, free it. */ 361 if (idtab->nentries < 1) 362 fatal("%s: internal error: nentries %d", 363 __func__, idtab->nentries); 364 TAILQ_REMOVE(&idtab->idlist, id, next); 365 free_identity(id); 366 idtab->nentries--; 367 sshkey_free(key); 368 success = 1; 369 done: 370 send_status(e, success); 371 } 372 373 static void 374 process_remove_all_identities(SocketEntry *e) 375 { 376 Identity *id; 377 378 /* Loop over all identities and clear the keys. */ 379 for (id = TAILQ_FIRST(&idtab->idlist); id; 380 id = TAILQ_FIRST(&idtab->idlist)) { 381 TAILQ_REMOVE(&idtab->idlist, id, next); 382 free_identity(id); 383 } 384 385 /* Mark that there are no identities. */ 386 idtab->nentries = 0; 387 388 /* Send success. */ 389 send_status(e, 1); 390 } 391 392 /* removes expired keys and returns number of seconds until the next expiry */ 393 static time_t 394 reaper(void) 395 { 396 time_t deadline = 0, now = monotime(); 397 Identity *id, *nxt; 398 399 for (id = TAILQ_FIRST(&idtab->idlist); id; id = nxt) { 400 nxt = TAILQ_NEXT(id, next); 401 if (id->death == 0) 402 continue; 403 if (now >= id->death) { 404 debug("expiring key '%s'", id->comment); 405 TAILQ_REMOVE(&idtab->idlist, id, next); 406 free_identity(id); 407 idtab->nentries--; 408 } else 409 deadline = (deadline == 0) ? id->death : 410 MINIMUM(deadline, id->death); 411 } 412 if (deadline == 0 || deadline <= now) 413 return 0; 414 else 415 return (deadline - now); 416 } 417 418 static void 419 process_add_identity(SocketEntry *e) 420 { 421 Identity *id; 422 int success = 0, confirm = 0; 423 u_int seconds, maxsign; 424 char *fp, *comment = NULL, *ext_name = NULL, *sk_provider = NULL; 425 char canonical_provider[PATH_MAX]; 426 time_t death = 0; 427 struct sshkey *k = NULL; 428 u_char ctype; 429 int r = SSH_ERR_INTERNAL_ERROR; 430 431 if ((r = sshkey_private_deserialize(e->request, &k)) != 0 || 432 k == NULL || 433 (r = sshbuf_get_cstring(e->request, &comment, NULL)) != 0) { 434 error("%s: decode private key: %s", __func__, ssh_err(r)); 435 goto err; 436 } 437 while (sshbuf_len(e->request)) { 438 if ((r = sshbuf_get_u8(e->request, &ctype)) != 0) { 439 error("%s: buffer error: %s", __func__, ssh_err(r)); 440 goto err; 441 } 442 switch (ctype) { 443 case SSH_AGENT_CONSTRAIN_LIFETIME: 444 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) { 445 error("%s: bad lifetime constraint: %s", 446 __func__, ssh_err(r)); 447 goto err; 448 } 449 death = monotime() + seconds; 450 break; 451 case SSH_AGENT_CONSTRAIN_CONFIRM: 452 confirm = 1; 453 break; 454 case SSH_AGENT_CONSTRAIN_MAXSIGN: 455 if ((r = sshbuf_get_u32(e->request, &maxsign)) != 0) { 456 error("%s: bad maxsign constraint: %s", 457 __func__, ssh_err(r)); 458 goto err; 459 } 460 if ((r = sshkey_enable_maxsign(k, maxsign)) != 0) { 461 error("%s: cannot enable maxsign: %s", 462 __func__, ssh_err(r)); 463 goto err; 464 } 465 break; 466 case SSH_AGENT_CONSTRAIN_EXTENSION: 467 if ((r = sshbuf_get_cstring(e->request, 468 &ext_name, NULL)) != 0) { 469 error("%s: cannot parse extension: %s", 470 __func__, ssh_err(r)); 471 goto err; 472 } 473 debug("%s: constraint ext %s", __func__, ext_name); 474 if (strcmp(ext_name, "sk-provider@openssh.com") == 0) { 475 if (sk_provider != NULL) { 476 error("%s already set", ext_name); 477 goto err; 478 } 479 if ((r = sshbuf_get_cstring(e->request, 480 &sk_provider, NULL)) != 0) { 481 error("%s: cannot parse %s: %s", 482 __func__, ext_name, ssh_err(r)); 483 goto err; 484 } 485 } else { 486 error("%s: unsupported constraint \"%s\"", 487 __func__, ext_name); 488 goto err; 489 } 490 free(ext_name); 491 break; 492 default: 493 error("%s: Unknown constraint %d", __func__, ctype); 494 err: 495 free(sk_provider); 496 free(ext_name); 497 sshbuf_reset(e->request); 498 free(comment); 499 sshkey_free(k); 500 goto send; 501 } 502 } 503 if (sk_provider != NULL) { 504 if (!sshkey_is_sk(k)) { 505 error("Cannot add provider: %s is not an " 506 "authenticator-hosted key", sshkey_type(k)); 507 free(sk_provider); 508 goto send; 509 } 510 if (strcasecmp(sk_provider, "internal") == 0) { 511 debug("%s: internal provider", __func__); 512 } else { 513 if (realpath(sk_provider, canonical_provider) == NULL) { 514 verbose("failed provider \"%.100s\": " 515 "realpath: %s", sk_provider, 516 strerror(errno)); 517 free(sk_provider); 518 goto send; 519 } 520 free(sk_provider); 521 sk_provider = xstrdup(canonical_provider); 522 if (match_pattern_list(sk_provider, 523 provider_whitelist, 0) != 1) { 524 error("Refusing add key: " 525 "provider %s not whitelisted", sk_provider); 526 free(sk_provider); 527 goto send; 528 } 529 } 530 } 531 if ((r = sshkey_shield_private(k)) != 0) { 532 error("%s: shield private key: %s", __func__, ssh_err(r)); 533 goto err; 534 } 535 536 success = 1; 537 if (lifetime && !death) 538 death = monotime() + lifetime; 539 if ((id = lookup_identity(k)) == NULL) { 540 id = xcalloc(1, sizeof(Identity)); 541 TAILQ_INSERT_TAIL(&idtab->idlist, id, next); 542 /* Increment the number of identities. */ 543 idtab->nentries++; 544 } else { 545 /* key state might have been updated */ 546 sshkey_free(id->key); 547 free(id->comment); 548 free(id->sk_provider); 549 } 550 id->key = k; 551 id->comment = comment; 552 id->death = death; 553 id->confirm = confirm; 554 id->sk_provider = sk_provider; 555 556 if ((fp = sshkey_fingerprint(k, SSH_FP_HASH_DEFAULT, 557 SSH_FP_DEFAULT)) == NULL) 558 fatal("%s: sshkey_fingerprint failed", __func__); 559 debug("%s: add %s %s \"%.100s\" (life: %u) (confirm: %u) " 560 "(provider: %s)", __func__, sshkey_ssh_name(k), fp, comment, 561 seconds, confirm, sk_provider == NULL ? "none" : sk_provider); 562 free(fp); 563 send: 564 send_status(e, success); 565 } 566 567 /* XXX todo: encrypt sensitive data with passphrase */ 568 static void 569 process_lock_agent(SocketEntry *e, int lock) 570 { 571 int r, success = 0, delay; 572 char *passwd; 573 u_char passwdhash[LOCK_SIZE]; 574 static u_int fail_count = 0; 575 size_t pwlen; 576 577 /* 578 * This is deliberately fatal: the user has requested that we lock, 579 * but we can't parse their request properly. The only safe thing to 580 * do is abort. 581 */ 582 if ((r = sshbuf_get_cstring(e->request, &passwd, &pwlen)) != 0) 583 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 584 if (pwlen == 0) { 585 debug("empty password not supported"); 586 } else if (locked && !lock) { 587 if (bcrypt_pbkdf(passwd, pwlen, (uint8_t *)lock_salt, sizeof(lock_salt), 588 (uint8_t *)passwdhash, sizeof(passwdhash), LOCK_ROUNDS) < 0) 589 fatal("bcrypt_pbkdf"); 590 if (timingsafe_bcmp(passwdhash, lock_pwhash, LOCK_SIZE) == 0) { 591 debug("agent unlocked"); 592 locked = 0; 593 fail_count = 0; 594 explicit_bzero(lock_pwhash, sizeof(lock_pwhash)); 595 success = 1; 596 } else { 597 /* delay in 0.1s increments up to 10s */ 598 if (fail_count < 100) 599 fail_count++; 600 delay = 100000 * fail_count; 601 debug("unlock failed, delaying %0.1lf seconds", 602 (double)delay/1000000); 603 usleep(delay); 604 } 605 explicit_bzero(passwdhash, sizeof(passwdhash)); 606 } else if (!locked && lock) { 607 debug("agent locked"); 608 locked = 1; 609 arc4random_buf(lock_salt, sizeof(lock_salt)); 610 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 611 lock_pwhash, sizeof(lock_pwhash), LOCK_ROUNDS) < 0) 612 fatal("bcrypt_pbkdf"); 613 success = 1; 614 } 615 explicit_bzero(passwd, pwlen); 616 free(passwd); 617 send_status(e, success); 618 } 619 620 static void 621 no_identities(SocketEntry *e) 622 { 623 struct sshbuf *msg; 624 int r; 625 626 if ((msg = sshbuf_new()) == NULL) 627 fatal("%s: sshbuf_new failed", __func__); 628 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 629 (r = sshbuf_put_u32(msg, 0)) != 0 || 630 (r = sshbuf_put_stringb(e->output, msg)) != 0) 631 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 632 sshbuf_free(msg); 633 } 634 635 #ifdef ENABLE_PKCS11 636 static void 637 process_add_smartcard_key(SocketEntry *e) 638 { 639 char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX]; 640 char **comments = NULL; 641 int r, i, count = 0, success = 0, confirm = 0; 642 u_int seconds; 643 time_t death = 0; 644 u_char type; 645 struct sshkey **keys = NULL, *k; 646 Identity *id; 647 648 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 649 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) { 650 error("%s: buffer error: %s", __func__, ssh_err(r)); 651 goto send; 652 } 653 654 while (sshbuf_len(e->request)) { 655 if ((r = sshbuf_get_u8(e->request, &type)) != 0) { 656 error("%s: buffer error: %s", __func__, ssh_err(r)); 657 goto send; 658 } 659 switch (type) { 660 case SSH_AGENT_CONSTRAIN_LIFETIME: 661 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) { 662 error("%s: buffer error: %s", 663 __func__, ssh_err(r)); 664 goto send; 665 } 666 death = monotime() + seconds; 667 break; 668 case SSH_AGENT_CONSTRAIN_CONFIRM: 669 confirm = 1; 670 break; 671 default: 672 error("%s: Unknown constraint type %d", __func__, type); 673 goto send; 674 } 675 } 676 if (realpath(provider, canonical_provider) == NULL) { 677 verbose("failed PKCS#11 add of \"%.100s\": realpath: %s", 678 provider, strerror(errno)); 679 goto send; 680 } 681 if (match_pattern_list(canonical_provider, provider_whitelist, 0) != 1) { 682 verbose("refusing PKCS#11 add of \"%.100s\": " 683 "provider not whitelisted", canonical_provider); 684 goto send; 685 } 686 debug("%s: add %.100s", __func__, canonical_provider); 687 if (lifetime && !death) 688 death = monotime() + lifetime; 689 690 count = pkcs11_add_provider(canonical_provider, pin, &keys, &comments); 691 for (i = 0; i < count; i++) { 692 k = keys[i]; 693 if (lookup_identity(k) == NULL) { 694 id = xcalloc(1, sizeof(Identity)); 695 id->key = k; 696 keys[i] = NULL; /* transferred */ 697 id->provider = xstrdup(canonical_provider); 698 if (*comments[i] != '\0') { 699 id->comment = comments[i]; 700 comments[i] = NULL; /* transferred */ 701 } else { 702 id->comment = xstrdup(canonical_provider); 703 } 704 id->death = death; 705 id->confirm = confirm; 706 TAILQ_INSERT_TAIL(&idtab->idlist, id, next); 707 idtab->nentries++; 708 success = 1; 709 } 710 sshkey_free(keys[i]); 711 free(comments[i]); 712 } 713 send: 714 free(pin); 715 free(provider); 716 free(keys); 717 free(comments); 718 send_status(e, success); 719 } 720 721 static void 722 process_remove_smartcard_key(SocketEntry *e) 723 { 724 char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX]; 725 int r, success = 0; 726 Identity *id, *nxt; 727 728 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 729 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) { 730 error("%s: buffer error: %s", __func__, ssh_err(r)); 731 goto send; 732 } 733 free(pin); 734 735 if (realpath(provider, canonical_provider) == NULL) { 736 verbose("failed PKCS#11 add of \"%.100s\": realpath: %s", 737 provider, strerror(errno)); 738 goto send; 739 } 740 741 debug("%s: remove %.100s", __func__, canonical_provider); 742 for (id = TAILQ_FIRST(&idtab->idlist); id; id = nxt) { 743 nxt = TAILQ_NEXT(id, next); 744 /* Skip file--based keys */ 745 if (id->provider == NULL) 746 continue; 747 if (!strcmp(canonical_provider, id->provider)) { 748 TAILQ_REMOVE(&idtab->idlist, id, next); 749 free_identity(id); 750 idtab->nentries--; 751 } 752 } 753 if (pkcs11_del_provider(canonical_provider) == 0) 754 success = 1; 755 else 756 error("%s: pkcs11_del_provider failed", __func__); 757 send: 758 free(provider); 759 send_status(e, success); 760 } 761 #endif /* ENABLE_PKCS11 */ 762 763 /* dispatch incoming messages */ 764 765 static int 766 process_message(u_int socknum) 767 { 768 u_int msg_len; 769 u_char type; 770 const u_char *cp; 771 int r; 772 SocketEntry *e; 773 774 if (socknum >= sockets_alloc) { 775 fatal("%s: socket number %u >= allocated %u", 776 __func__, socknum, sockets_alloc); 777 } 778 e = &sockets[socknum]; 779 780 if (sshbuf_len(e->input) < 5) 781 return 0; /* Incomplete message header. */ 782 cp = sshbuf_ptr(e->input); 783 msg_len = PEEK_U32(cp); 784 if (msg_len > AGENT_MAX_LEN) { 785 debug("%s: socket %u (fd=%d) message too long %u > %u", 786 __func__, socknum, e->fd, msg_len, AGENT_MAX_LEN); 787 return -1; 788 } 789 if (sshbuf_len(e->input) < msg_len + 4) 790 return 0; /* Incomplete message body. */ 791 792 /* move the current input to e->request */ 793 sshbuf_reset(e->request); 794 if ((r = sshbuf_get_stringb(e->input, e->request)) != 0 || 795 (r = sshbuf_get_u8(e->request, &type)) != 0) { 796 if (r == SSH_ERR_MESSAGE_INCOMPLETE || 797 r == SSH_ERR_STRING_TOO_LARGE) { 798 debug("%s: buffer error: %s", __func__, ssh_err(r)); 799 return -1; 800 } 801 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 802 } 803 804 debug("%s: socket %u (fd=%d) type %d", __func__, socknum, e->fd, type); 805 806 /* check whether agent is locked */ 807 if (locked && type != SSH_AGENTC_UNLOCK) { 808 sshbuf_reset(e->request); 809 switch (type) { 810 case SSH2_AGENTC_REQUEST_IDENTITIES: 811 /* send empty lists */ 812 no_identities(e); 813 break; 814 default: 815 /* send a fail message for all other request types */ 816 send_status(e, 0); 817 } 818 return 0; 819 } 820 821 switch (type) { 822 case SSH_AGENTC_LOCK: 823 case SSH_AGENTC_UNLOCK: 824 process_lock_agent(e, type == SSH_AGENTC_LOCK); 825 break; 826 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 827 process_remove_all_identities(e); /* safe for !WITH_SSH1 */ 828 break; 829 /* ssh2 */ 830 case SSH2_AGENTC_SIGN_REQUEST: 831 process_sign_request2(e); 832 break; 833 case SSH2_AGENTC_REQUEST_IDENTITIES: 834 process_request_identities(e); 835 break; 836 case SSH2_AGENTC_ADD_IDENTITY: 837 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 838 process_add_identity(e); 839 break; 840 case SSH2_AGENTC_REMOVE_IDENTITY: 841 process_remove_identity(e); 842 break; 843 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 844 process_remove_all_identities(e); 845 break; 846 #ifdef ENABLE_PKCS11 847 case SSH_AGENTC_ADD_SMARTCARD_KEY: 848 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 849 process_add_smartcard_key(e); 850 break; 851 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 852 process_remove_smartcard_key(e); 853 break; 854 #endif /* ENABLE_PKCS11 */ 855 default: 856 /* Unknown message. Respond with failure. */ 857 error("Unknown message %d", type); 858 sshbuf_reset(e->request); 859 send_status(e, 0); 860 break; 861 } 862 return 0; 863 } 864 865 static void 866 new_socket(sock_type type, int fd) 867 { 868 u_int i, old_alloc, new_alloc; 869 870 set_nonblock(fd); 871 872 if (fd > max_fd) 873 max_fd = fd; 874 875 for (i = 0; i < sockets_alloc; i++) 876 if (sockets[i].type == AUTH_UNUSED) { 877 sockets[i].fd = fd; 878 if ((sockets[i].input = sshbuf_new()) == NULL) 879 fatal("%s: sshbuf_new failed", __func__); 880 if ((sockets[i].output = sshbuf_new()) == NULL) 881 fatal("%s: sshbuf_new failed", __func__); 882 if ((sockets[i].request = sshbuf_new()) == NULL) 883 fatal("%s: sshbuf_new failed", __func__); 884 sockets[i].type = type; 885 return; 886 } 887 old_alloc = sockets_alloc; 888 new_alloc = sockets_alloc + 10; 889 sockets = xreallocarray(sockets, new_alloc, sizeof(sockets[0])); 890 for (i = old_alloc; i < new_alloc; i++) 891 sockets[i].type = AUTH_UNUSED; 892 sockets_alloc = new_alloc; 893 sockets[old_alloc].fd = fd; 894 if ((sockets[old_alloc].input = sshbuf_new()) == NULL) 895 fatal("%s: sshbuf_new failed", __func__); 896 if ((sockets[old_alloc].output = sshbuf_new()) == NULL) 897 fatal("%s: sshbuf_new failed", __func__); 898 if ((sockets[old_alloc].request = sshbuf_new()) == NULL) 899 fatal("%s: sshbuf_new failed", __func__); 900 sockets[old_alloc].type = type; 901 } 902 903 static int 904 handle_socket_read(u_int socknum) 905 { 906 struct sockaddr_un sunaddr; 907 socklen_t slen; 908 uid_t euid; 909 gid_t egid; 910 int fd; 911 912 slen = sizeof(sunaddr); 913 fd = accept(sockets[socknum].fd, (struct sockaddr *)&sunaddr, &slen); 914 if (fd == -1) { 915 error("accept from AUTH_SOCKET: %s", strerror(errno)); 916 return -1; 917 } 918 if (getpeereid(fd, &euid, &egid) == -1) { 919 error("getpeereid %d failed: %s", fd, strerror(errno)); 920 close(fd); 921 return -1; 922 } 923 if ((euid != 0) && (getuid() != euid)) { 924 error("uid mismatch: peer euid %u != uid %u", 925 (u_int) euid, (u_int) getuid()); 926 close(fd); 927 return -1; 928 } 929 new_socket(AUTH_CONNECTION, fd); 930 return 0; 931 } 932 933 static int 934 handle_conn_read(u_int socknum) 935 { 936 char buf[AGENT_RBUF_LEN]; 937 ssize_t len; 938 int r; 939 940 if ((len = read(sockets[socknum].fd, buf, sizeof(buf))) <= 0) { 941 if (len == -1) { 942 if (errno == EAGAIN || errno == EINTR) 943 return 0; 944 error("%s: read error on socket %u (fd %d): %s", 945 __func__, socknum, sockets[socknum].fd, 946 strerror(errno)); 947 } 948 return -1; 949 } 950 if ((r = sshbuf_put(sockets[socknum].input, buf, len)) != 0) 951 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 952 explicit_bzero(buf, sizeof(buf)); 953 process_message(socknum); 954 return 0; 955 } 956 957 static int 958 handle_conn_write(u_int socknum) 959 { 960 ssize_t len; 961 int r; 962 963 if (sshbuf_len(sockets[socknum].output) == 0) 964 return 0; /* shouldn't happen */ 965 if ((len = write(sockets[socknum].fd, 966 sshbuf_ptr(sockets[socknum].output), 967 sshbuf_len(sockets[socknum].output))) <= 0) { 968 if (len == -1) { 969 if (errno == EAGAIN || errno == EINTR) 970 return 0; 971 error("%s: read error on socket %u (fd %d): %s", 972 __func__, socknum, sockets[socknum].fd, 973 strerror(errno)); 974 } 975 return -1; 976 } 977 if ((r = sshbuf_consume(sockets[socknum].output, len)) != 0) 978 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 979 return 0; 980 } 981 982 static void 983 after_poll(struct pollfd *pfd, size_t npfd, u_int maxfds) 984 { 985 size_t i; 986 u_int socknum, activefds = npfd; 987 988 for (i = 0; i < npfd; i++) { 989 if (pfd[i].revents == 0) 990 continue; 991 /* Find sockets entry */ 992 for (socknum = 0; socknum < sockets_alloc; socknum++) { 993 if (sockets[socknum].type != AUTH_SOCKET && 994 sockets[socknum].type != AUTH_CONNECTION) 995 continue; 996 if (pfd[i].fd == sockets[socknum].fd) 997 break; 998 } 999 if (socknum >= sockets_alloc) { 1000 error("%s: no socket for fd %d", __func__, pfd[i].fd); 1001 continue; 1002 } 1003 /* Process events */ 1004 switch (sockets[socknum].type) { 1005 case AUTH_SOCKET: 1006 if ((pfd[i].revents & (POLLIN|POLLERR)) == 0) 1007 break; 1008 if (npfd > maxfds) { 1009 debug3("out of fds (active %u >= limit %u); " 1010 "skipping accept", activefds, maxfds); 1011 break; 1012 } 1013 if (handle_socket_read(socknum) == 0) 1014 activefds++; 1015 break; 1016 case AUTH_CONNECTION: 1017 if ((pfd[i].revents & (POLLIN|POLLERR)) != 0 && 1018 handle_conn_read(socknum) != 0) { 1019 goto close_sock; 1020 } 1021 if ((pfd[i].revents & (POLLOUT|POLLHUP)) != 0 && 1022 handle_conn_write(socknum) != 0) { 1023 close_sock: 1024 if (activefds == 0) 1025 fatal("activefds == 0 at close_sock"); 1026 close_socket(&sockets[socknum]); 1027 activefds--; 1028 break; 1029 } 1030 break; 1031 default: 1032 break; 1033 } 1034 } 1035 } 1036 1037 static int 1038 prepare_poll(struct pollfd **pfdp, size_t *npfdp, int *timeoutp, u_int maxfds) 1039 { 1040 struct pollfd *pfd = *pfdp; 1041 size_t i, j, npfd = 0; 1042 time_t deadline; 1043 int r; 1044 1045 /* Count active sockets */ 1046 for (i = 0; i < sockets_alloc; i++) { 1047 switch (sockets[i].type) { 1048 case AUTH_SOCKET: 1049 case AUTH_CONNECTION: 1050 npfd++; 1051 break; 1052 case AUTH_UNUSED: 1053 break; 1054 default: 1055 fatal("Unknown socket type %d", sockets[i].type); 1056 break; 1057 } 1058 } 1059 if (npfd != *npfdp && 1060 (pfd = recallocarray(pfd, *npfdp, npfd, sizeof(*pfd))) == NULL) 1061 fatal("%s: recallocarray failed", __func__); 1062 *pfdp = pfd; 1063 *npfdp = npfd; 1064 1065 for (i = j = 0; i < sockets_alloc; i++) { 1066 switch (sockets[i].type) { 1067 case AUTH_SOCKET: 1068 if (npfd > maxfds) { 1069 debug3("out of fds (active %zu >= limit %u); " 1070 "skipping arming listener", npfd, maxfds); 1071 break; 1072 } 1073 pfd[j].fd = sockets[i].fd; 1074 pfd[j].revents = 0; 1075 pfd[j].events = POLLIN; 1076 j++; 1077 break; 1078 case AUTH_CONNECTION: 1079 pfd[j].fd = sockets[i].fd; 1080 pfd[j].revents = 0; 1081 /* 1082 * Only prepare to read if we can handle a full-size 1083 * input read buffer and enqueue a max size reply.. 1084 */ 1085 if ((r = sshbuf_check_reserve(sockets[i].input, 1086 AGENT_RBUF_LEN)) == 0 && 1087 (r = sshbuf_check_reserve(sockets[i].output, 1088 AGENT_MAX_LEN)) == 0) 1089 pfd[j].events = POLLIN; 1090 else if (r != SSH_ERR_NO_BUFFER_SPACE) { 1091 fatal("%s: buffer error: %s", 1092 __func__, ssh_err(r)); 1093 } 1094 if (sshbuf_len(sockets[i].output) > 0) 1095 pfd[j].events |= POLLOUT; 1096 j++; 1097 break; 1098 default: 1099 break; 1100 } 1101 } 1102 deadline = reaper(); 1103 if (parent_alive_interval != 0) 1104 deadline = (deadline == 0) ? parent_alive_interval : 1105 MINIMUM(deadline, parent_alive_interval); 1106 if (deadline == 0) { 1107 *timeoutp = -1; /* INFTIM */ 1108 } else { 1109 if (deadline > INT_MAX / 1000) 1110 *timeoutp = INT_MAX / 1000; 1111 else 1112 *timeoutp = deadline * 1000; 1113 } 1114 return (1); 1115 } 1116 1117 static void 1118 cleanup_socket(void) 1119 { 1120 if (cleanup_pid != 0 && getpid() != cleanup_pid) 1121 return; 1122 debug("%s: cleanup", __func__); 1123 if (socket_name[0]) 1124 unlink(socket_name); 1125 if (socket_dir[0]) 1126 rmdir(socket_dir); 1127 } 1128 1129 void 1130 cleanup_exit(int i) 1131 { 1132 cleanup_socket(); 1133 _exit(i); 1134 } 1135 1136 /*ARGSUSED*/ 1137 __dead static void 1138 cleanup_handler(int sig) 1139 { 1140 cleanup_socket(); 1141 #ifdef ENABLE_PKCS11 1142 pkcs11_terminate(); 1143 #endif 1144 _exit(2); 1145 } 1146 1147 static void 1148 check_parent_exists(void) 1149 { 1150 /* 1151 * If our parent has exited then getppid() will return (pid_t)1, 1152 * so testing for that should be safe. 1153 */ 1154 if (parent_pid != -1 && getppid() != parent_pid) { 1155 /* printf("Parent has died - Authentication agent exiting.\n"); */ 1156 cleanup_socket(); 1157 _exit(2); 1158 } 1159 } 1160 1161 __dead static void 1162 usage(void) 1163 { 1164 fprintf(stderr, 1165 "usage: ssh-agent [-c | -s] [-Dd] [-a bind_address] [-E fingerprint_hash]\n" 1166 " [-P provider_whitelist] [-t life] [command [arg ...]]\n" 1167 " ssh-agent [-c | -s] -k\n"); 1168 exit(1); 1169 } 1170 1171 static void 1172 csh_setenv(const char *name, const char *value) 1173 { 1174 printf("setenv %s %s;\n", name, value); 1175 } 1176 1177 static void 1178 csh_unsetenv(const char *name) 1179 { 1180 printf("unsetenv %s;\n", name); 1181 } 1182 1183 static void 1184 sh_setenv(const char *name, const char *value) 1185 { 1186 printf("%s=%s; export %s;\n", name, value, name); 1187 } 1188 1189 static void 1190 sh_unsetenv(const char *name) 1191 { 1192 printf("unset %s;\n", name); 1193 } 1194 int 1195 main(int ac, char **av) 1196 { 1197 int c_flag = 0, d_flag = 0, D_flag = 0, k_flag = 0, s_flag = 0; 1198 int sock, fd, ch, result, saved_errno; 1199 char *shell, *pidstr, *agentsocket = NULL; 1200 struct rlimit rlim; 1201 void (*f_setenv)(const char *, const char *); 1202 void (*f_unsetenv)(const char *); 1203 extern int optind; 1204 extern char *optarg; 1205 pid_t pid; 1206 char pidstrbuf[1 + 3 * sizeof pid]; 1207 size_t len; 1208 mode_t prev_mask; 1209 int timeout = -1; /* INFTIM */ 1210 struct pollfd *pfd = NULL; 1211 size_t npfd = 0; 1212 u_int maxfds; 1213 1214 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1215 sanitise_stdfd(); 1216 1217 /* drop */ 1218 setegid(getgid()); 1219 setgid(getgid()); 1220 1221 if (getrlimit(RLIMIT_NOFILE, &rlim) == -1) 1222 fatal("%s: getrlimit: %s", __progname, strerror(errno)); 1223 1224 #ifdef WITH_OPENSSL 1225 OpenSSL_add_all_algorithms(); 1226 #endif 1227 1228 while ((ch = getopt(ac, av, "cDdksE:a:P:t:")) != -1) { 1229 switch (ch) { 1230 case 'E': 1231 fingerprint_hash = ssh_digest_alg_by_name(optarg); 1232 if (fingerprint_hash == -1) 1233 fatal("Invalid hash algorithm \"%s\"", optarg); 1234 break; 1235 case 'c': 1236 if (s_flag) 1237 usage(); 1238 c_flag++; 1239 break; 1240 case 'k': 1241 k_flag++; 1242 break; 1243 case 'P': 1244 if (provider_whitelist != NULL) 1245 fatal("-P option already specified"); 1246 provider_whitelist = xstrdup(optarg); 1247 break; 1248 case 's': 1249 if (c_flag) 1250 usage(); 1251 s_flag++; 1252 break; 1253 case 'd': 1254 if (d_flag || D_flag) 1255 usage(); 1256 d_flag++; 1257 break; 1258 case 'D': 1259 if (d_flag || D_flag) 1260 usage(); 1261 D_flag++; 1262 break; 1263 case 'a': 1264 agentsocket = optarg; 1265 break; 1266 case 't': 1267 if ((lifetime = convtime(optarg)) == -1) { 1268 fprintf(stderr, "Invalid lifetime\n"); 1269 usage(); 1270 } 1271 break; 1272 default: 1273 usage(); 1274 } 1275 } 1276 ac -= optind; 1277 av += optind; 1278 1279 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag || D_flag)) 1280 usage(); 1281 1282 if (provider_whitelist == NULL) 1283 provider_whitelist = xstrdup(DEFAULT_PROVIDER_WHITELIST); 1284 1285 if (ac == 0 && !c_flag && !s_flag) { 1286 shell = getenv("SHELL"); 1287 if (shell != NULL && (len = strlen(shell)) > 2 && 1288 strncmp(shell + len - 3, "csh", 3) == 0) 1289 c_flag = 1; 1290 } 1291 if (c_flag) { 1292 f_setenv = csh_setenv; 1293 f_unsetenv = csh_unsetenv; 1294 } else { 1295 f_setenv = sh_setenv; 1296 f_unsetenv = sh_unsetenv; 1297 } 1298 if (k_flag) { 1299 const char *errstr = NULL; 1300 1301 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1302 if (pidstr == NULL) { 1303 fprintf(stderr, "%s not set, cannot kill agent\n", 1304 SSH_AGENTPID_ENV_NAME); 1305 exit(1); 1306 } 1307 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr); 1308 if (errstr) { 1309 fprintf(stderr, 1310 "%s=\"%s\", which is not a good PID: %s\n", 1311 SSH_AGENTPID_ENV_NAME, pidstr, errstr); 1312 exit(1); 1313 } 1314 if (kill(pid, SIGTERM) == -1) { 1315 perror("kill"); 1316 exit(1); 1317 } 1318 (*f_unsetenv)(SSH_AUTHSOCKET_ENV_NAME); 1319 (*f_unsetenv)(SSH_AGENTPID_ENV_NAME); 1320 printf("echo Agent pid %ld killed;\n", (long)pid); 1321 exit(0); 1322 } 1323 1324 /* 1325 * Minimum file descriptors: 1326 * stdio (3) + listener (1) + syslog (1 maybe) + connection (1) + 1327 * a few spare for libc / stack protectors / sanitisers, etc. 1328 */ 1329 #define SSH_AGENT_MIN_FDS (3+1+1+1+4) 1330 if (rlim.rlim_cur < SSH_AGENT_MIN_FDS) 1331 fatal("%s: file descriptor rlimit %lld too low (minimum %u)", 1332 __progname, (long long)rlim.rlim_cur, SSH_AGENT_MIN_FDS); 1333 maxfds = rlim.rlim_cur - SSH_AGENT_MIN_FDS; 1334 1335 parent_pid = getpid(); 1336 1337 if (agentsocket == NULL) { 1338 /* Create private directory for agent socket */ 1339 mktemp_proto(socket_dir, sizeof(socket_dir)); 1340 if (mkdtemp(socket_dir) == NULL) { 1341 perror("mkdtemp: private socket dir"); 1342 exit(1); 1343 } 1344 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1345 (long)parent_pid); 1346 } else { 1347 /* Try to use specified agent socket */ 1348 socket_dir[0] = '\0'; 1349 strlcpy(socket_name, agentsocket, sizeof socket_name); 1350 } 1351 1352 /* 1353 * Create socket early so it will exist before command gets run from 1354 * the parent. 1355 */ 1356 prev_mask = umask(0177); 1357 sock = unix_listener(socket_name, SSH_LISTEN_BACKLOG, 0); 1358 if (sock < 0) { 1359 /* XXX - unix_listener() calls error() not perror() */ 1360 *socket_name = '\0'; /* Don't unlink any existing file */ 1361 cleanup_exit(1); 1362 } 1363 umask(prev_mask); 1364 1365 /* 1366 * Fork, and have the parent execute the command, if any, or present 1367 * the socket data. The child continues as the authentication agent. 1368 */ 1369 if (D_flag || d_flag) { 1370 log_init(__progname, 1371 d_flag ? SYSLOG_LEVEL_DEBUG3 : SYSLOG_LEVEL_INFO, 1372 SYSLOG_FACILITY_AUTH, 1); 1373 if (c_flag) 1374 printf("setenv %s %s;\n", 1375 SSH_AUTHSOCKET_ENV_NAME, socket_name); 1376 else 1377 printf("%s=%s; export %s;\n", 1378 SSH_AUTHSOCKET_ENV_NAME, socket_name, 1379 SSH_AUTHSOCKET_ENV_NAME); 1380 printf("echo Agent pid %ld;\n", (long)parent_pid); 1381 fflush(stdout); 1382 goto skip; 1383 } 1384 pid = fork(); 1385 if (pid == -1) { 1386 perror("fork"); 1387 cleanup_exit(1); 1388 } 1389 if (pid != 0) { /* Parent - execute the given command. */ 1390 close(sock); 1391 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1392 if (ac == 0) { 1393 (*f_setenv)(SSH_AUTHSOCKET_ENV_NAME, socket_name); 1394 (*f_setenv)(SSH_AGENTPID_ENV_NAME, pidstrbuf); 1395 printf("echo Agent pid %ld;\n", (long)pid); 1396 exit(0); 1397 } 1398 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1399 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1400 perror("setenv"); 1401 exit(1); 1402 } 1403 execvp(av[0], av); 1404 perror(av[0]); 1405 exit(1); 1406 } 1407 /* child */ 1408 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1409 1410 if (setsid() == -1) { 1411 error("setsid: %s", strerror(errno)); 1412 cleanup_exit(1); 1413 } 1414 1415 (void)chdir("/"); 1416 1417 if (sock != STDERR_FILENO + 1) { 1418 if (dup2(sock, STDERR_FILENO + 1) == -1) { 1419 error("dup2: %s", strerror(errno)); 1420 cleanup_exit(1); 1421 } 1422 close(sock); 1423 sock = STDERR_FILENO + 1; 1424 } 1425 #if defined(F_CLOSEM) 1426 if (fcntl(sock + 1, F_CLOSEM, 0) == -1) { 1427 error("fcntl F_CLOSEM: %s", strerror(errno)); 1428 cleanup_exit(1); 1429 } 1430 #else 1431 { 1432 int nfiles; 1433 #if defined(_SC_OPEN_MAX) 1434 nfiles = sysconf(_SC_OPEN_MAX); 1435 #elif defined(RLIMIT_NOFILE) 1436 if (getrlimit(RLIMIT_CORE, &rlim) < 0) { 1437 error("getrlimit RLIMIT_NOFILE: %s", strerror(errno)); 1438 cleanup_exit(1); 1439 } 1440 nfiles = rlim.rlim_cur; 1441 #elif defined(OPEN_MAX) 1442 nfiles = OPEN_MAX; 1443 #elif defined(NOFILE) 1444 nfiles = NOFILE; 1445 #else 1446 nfiles = 1024; 1447 #endif 1448 for (fd = sock + 1; fd < nfiles; fd++) 1449 close(fd); 1450 } 1451 #endif 1452 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1453 if (dup2(fd, STDIN_FILENO) == -1 || 1454 dup2(fd, STDOUT_FILENO) == -1 || 1455 dup2(fd, STDERR_FILENO) == -1) { 1456 error("dup2: %s", strerror(errno)); 1457 cleanup_exit(1); 1458 } 1459 if (fd > STDERR_FILENO) 1460 close(fd); 1461 } 1462 1463 /* deny core dumps, since memory contains unencrypted private keys */ 1464 rlim.rlim_cur = rlim.rlim_max = 0; 1465 if (setrlimit(RLIMIT_CORE, &rlim) == -1) { 1466 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1467 cleanup_exit(1); 1468 } 1469 1470 skip: 1471 1472 cleanup_pid = getpid(); 1473 1474 #ifdef ENABLE_PKCS11 1475 pkcs11_init(0); 1476 #endif 1477 new_socket(AUTH_SOCKET, sock); 1478 if (ac > 0) 1479 parent_alive_interval = 10; 1480 idtab_init(); 1481 ssh_signal(SIGPIPE, SIG_IGN); 1482 ssh_signal(SIGINT, (d_flag | D_flag) ? cleanup_handler : SIG_IGN); 1483 ssh_signal(SIGHUP, cleanup_handler); 1484 ssh_signal(SIGTERM, cleanup_handler); 1485 1486 #ifdef __OpenBSD__ 1487 if (pledge("stdio rpath cpath unix id proc exec", NULL) == -1) 1488 fatal("%s: pledge: %s", __progname, strerror(errno)); 1489 #endif 1490 1491 while (1) { 1492 prepare_poll(&pfd, &npfd, &timeout, maxfds); 1493 result = poll(pfd, npfd, timeout); 1494 saved_errno = errno; 1495 if (parent_alive_interval != 0) 1496 check_parent_exists(); 1497 (void) reaper(); /* remove expired keys */ 1498 if (result == -1) { 1499 if (saved_errno == EINTR) 1500 continue; 1501 fatal("poll: %s", strerror(saved_errno)); 1502 } else if (result > 0) 1503 after_poll(pfd, npfd, maxfds); 1504 } 1505 /* NOTREACHED */ 1506 } 1507