1 /* $OpenBSD: ssh-agent.c,v 1.257 2020/03/06 18:28:27 markus Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * The authentication agent program. 7 * 8 * As far as I am concerned, the code I have written for this software 9 * can be used freely for any purpose. Any derived versions of this 10 * software must be clearly marked as such, and if the derived work is 11 * incompatible with the protocol description in the RFC file, it must be 12 * called by a name other than "ssh" or "Secure Shell". 13 * 14 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 15 * 16 * Redistribution and use in source and binary forms, with or without 17 * modification, are permitted provided that the following conditions 18 * are met: 19 * 1. Redistributions of source code must retain the above copyright 20 * notice, this list of conditions and the following disclaimer. 21 * 2. Redistributions in binary form must reproduce the above copyright 22 * notice, this list of conditions and the following disclaimer in the 23 * documentation and/or other materials provided with the distribution. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 26 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 27 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 28 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 29 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 30 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 31 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 34 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 35 */ 36 37 #include "includes.h" 38 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 #include <sys/wait.h> 45 #ifdef HAVE_SYS_TIME_H 46 # include <sys/time.h> 47 #endif 48 #ifdef HAVE_SYS_UN_H 49 # include <sys/un.h> 50 #endif 51 #include "openbsd-compat/sys-queue.h" 52 53 #ifdef WITH_OPENSSL 54 #include <openssl/evp.h> 55 #include "openbsd-compat/openssl-compat.h" 56 #endif 57 58 #include <errno.h> 59 #include <fcntl.h> 60 #include <limits.h> 61 #ifdef HAVE_PATHS_H 62 # include <paths.h> 63 #endif 64 #ifdef HAVE_POLL_H 65 # include <poll.h> 66 #endif 67 #include <signal.h> 68 #include <stdarg.h> 69 #include <stdio.h> 70 #include <stdlib.h> 71 #include <time.h> 72 #include <string.h> 73 #include <unistd.h> 74 #ifdef HAVE_UTIL_H 75 # include <util.h> 76 #endif 77 78 #include "xmalloc.h" 79 #include "ssh.h" 80 #include "sshbuf.h" 81 #include "sshkey.h" 82 #include "authfd.h" 83 #include "compat.h" 84 #include "log.h" 85 #include "misc.h" 86 #include "digest.h" 87 #include "ssherr.h" 88 #include "match.h" 89 #include "msg.h" 90 #include "ssherr.h" 91 #include "pathnames.h" 92 #include "ssh-pkcs11.h" 93 #include "sk-api.h" 94 95 #ifndef DEFAULT_PROVIDER_WHITELIST 96 # define DEFAULT_PROVIDER_WHITELIST "/usr/lib*/*,/usr/local/lib*/*" 97 #endif 98 99 /* Maximum accepted message length */ 100 #define AGENT_MAX_LEN (256*1024) 101 /* Maximum bytes to read from client socket */ 102 #define AGENT_RBUF_LEN (4096) 103 104 typedef enum { 105 AUTH_UNUSED, 106 AUTH_SOCKET, 107 AUTH_CONNECTION 108 } sock_type; 109 110 typedef struct { 111 int fd; 112 sock_type type; 113 struct sshbuf *input; 114 struct sshbuf *output; 115 struct sshbuf *request; 116 } SocketEntry; 117 118 u_int sockets_alloc = 0; 119 SocketEntry *sockets = NULL; 120 121 typedef struct identity { 122 TAILQ_ENTRY(identity) next; 123 struct sshkey *key; 124 char *comment; 125 char *provider; 126 time_t death; 127 u_int confirm; 128 char *sk_provider; 129 } Identity; 130 131 struct idtable { 132 int nentries; 133 TAILQ_HEAD(idqueue, identity) idlist; 134 }; 135 136 /* private key table */ 137 struct idtable *idtab; 138 139 int max_fd = 0; 140 141 /* pid of shell == parent of agent */ 142 pid_t parent_pid = -1; 143 time_t parent_alive_interval = 0; 144 145 /* pid of process for which cleanup_socket is applicable */ 146 pid_t cleanup_pid = 0; 147 148 /* pathname and directory for AUTH_SOCKET */ 149 char socket_name[PATH_MAX]; 150 char socket_dir[PATH_MAX]; 151 152 /* PKCS#11/Security key path whitelist */ 153 static char *provider_whitelist; 154 155 /* locking */ 156 #define LOCK_SIZE 32 157 #define LOCK_SALT_SIZE 16 158 #define LOCK_ROUNDS 1 159 int locked = 0; 160 u_char lock_pwhash[LOCK_SIZE]; 161 u_char lock_salt[LOCK_SALT_SIZE]; 162 163 extern char *__progname; 164 165 /* Default lifetime in seconds (0 == forever) */ 166 static long lifetime = 0; 167 168 static int fingerprint_hash = SSH_FP_HASH_DEFAULT; 169 170 static void 171 close_socket(SocketEntry *e) 172 { 173 close(e->fd); 174 e->fd = -1; 175 e->type = AUTH_UNUSED; 176 sshbuf_free(e->input); 177 sshbuf_free(e->output); 178 sshbuf_free(e->request); 179 } 180 181 static void 182 idtab_init(void) 183 { 184 idtab = xcalloc(1, sizeof(*idtab)); 185 TAILQ_INIT(&idtab->idlist); 186 idtab->nentries = 0; 187 } 188 189 static void 190 free_identity(Identity *id) 191 { 192 sshkey_free(id->key); 193 free(id->provider); 194 free(id->comment); 195 free(id->sk_provider); 196 free(id); 197 } 198 199 /* return matching private key for given public key */ 200 static Identity * 201 lookup_identity(struct sshkey *key) 202 { 203 Identity *id; 204 205 TAILQ_FOREACH(id, &idtab->idlist, next) { 206 if (sshkey_equal(key, id->key)) 207 return (id); 208 } 209 return (NULL); 210 } 211 212 /* Check confirmation of keysign request */ 213 static int 214 confirm_key(Identity *id) 215 { 216 char *p; 217 int ret = -1; 218 219 p = sshkey_fingerprint(id->key, fingerprint_hash, SSH_FP_DEFAULT); 220 if (p != NULL && 221 ask_permission("Allow use of key %s?\nKey fingerprint %s.", 222 id->comment, p)) 223 ret = 0; 224 free(p); 225 226 return (ret); 227 } 228 229 static void 230 send_status(SocketEntry *e, int success) 231 { 232 int r; 233 234 if ((r = sshbuf_put_u32(e->output, 1)) != 0 || 235 (r = sshbuf_put_u8(e->output, success ? 236 SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0) 237 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 238 } 239 240 /* send list of supported public keys to 'client' */ 241 static void 242 process_request_identities(SocketEntry *e) 243 { 244 Identity *id; 245 struct sshbuf *msg; 246 int r; 247 248 if ((msg = sshbuf_new()) == NULL) 249 fatal("%s: sshbuf_new failed", __func__); 250 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 251 (r = sshbuf_put_u32(msg, idtab->nentries)) != 0) 252 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 253 TAILQ_FOREACH(id, &idtab->idlist, next) { 254 if ((r = sshkey_puts_opts(id->key, msg, SSHKEY_SERIALIZE_INFO)) 255 != 0 || 256 (r = sshbuf_put_cstring(msg, id->comment)) != 0) { 257 error("%s: put key/comment: %s", __func__, 258 ssh_err(r)); 259 continue; 260 } 261 } 262 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 263 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 264 sshbuf_free(msg); 265 } 266 267 268 static char * 269 agent_decode_alg(struct sshkey *key, u_int flags) 270 { 271 if (key->type == KEY_RSA) { 272 if (flags & SSH_AGENT_RSA_SHA2_256) 273 return "rsa-sha2-256"; 274 else if (flags & SSH_AGENT_RSA_SHA2_512) 275 return "rsa-sha2-512"; 276 } else if (key->type == KEY_RSA_CERT) { 277 if (flags & SSH_AGENT_RSA_SHA2_256) 278 return "rsa-sha2-256-cert-v01@openssh.com"; 279 else if (flags & SSH_AGENT_RSA_SHA2_512) 280 return "rsa-sha2-512-cert-v01@openssh.com"; 281 } 282 return NULL; 283 } 284 285 /* ssh2 only */ 286 static void 287 process_sign_request2(SocketEntry *e) 288 { 289 const u_char *data; 290 u_char *signature = NULL; 291 size_t dlen, slen = 0; 292 u_int compat = 0, flags; 293 int r, ok = -1; 294 char *fp = NULL; 295 struct sshbuf *msg; 296 struct sshkey *key = NULL; 297 struct identity *id; 298 struct notifier_ctx *notifier = NULL; 299 300 if ((msg = sshbuf_new()) == NULL) 301 fatal("%s: sshbuf_new failed", __func__); 302 if ((r = sshkey_froms(e->request, &key)) != 0 || 303 (r = sshbuf_get_string_direct(e->request, &data, &dlen)) != 0 || 304 (r = sshbuf_get_u32(e->request, &flags)) != 0) { 305 error("%s: couldn't parse request: %s", __func__, ssh_err(r)); 306 goto send; 307 } 308 309 if ((id = lookup_identity(key)) == NULL) { 310 verbose("%s: %s key not found", __func__, sshkey_type(key)); 311 goto send; 312 } 313 if (id->confirm && confirm_key(id) != 0) { 314 verbose("%s: user refused key", __func__); 315 goto send; 316 } 317 if (sshkey_is_sk(id->key) && 318 (id->key->sk_flags & SSH_SK_USER_PRESENCE_REQD)) { 319 if ((fp = sshkey_fingerprint(key, SSH_FP_HASH_DEFAULT, 320 SSH_FP_DEFAULT)) == NULL) 321 fatal("%s: fingerprint failed", __func__); 322 notifier = notify_start(0, 323 "Confirm user presence for key %s %s", 324 sshkey_type(id->key), fp); 325 } 326 if ((r = sshkey_sign(id->key, &signature, &slen, 327 data, dlen, agent_decode_alg(key, flags), 328 id->sk_provider, compat)) != 0) { 329 error("%s: sshkey_sign: %s", __func__, ssh_err(r)); 330 goto send; 331 } 332 /* Success */ 333 ok = 0; 334 send: 335 notify_complete(notifier); 336 sshkey_free(key); 337 free(fp); 338 if (ok == 0) { 339 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 || 340 (r = sshbuf_put_string(msg, signature, slen)) != 0) 341 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 342 } else if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0) 343 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 344 345 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 346 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 347 348 sshbuf_free(msg); 349 free(signature); 350 } 351 352 /* shared */ 353 static void 354 process_remove_identity(SocketEntry *e) 355 { 356 int r, success = 0; 357 struct sshkey *key = NULL; 358 Identity *id; 359 360 if ((r = sshkey_froms(e->request, &key)) != 0) { 361 error("%s: get key: %s", __func__, ssh_err(r)); 362 goto done; 363 } 364 if ((id = lookup_identity(key)) == NULL) { 365 debug("%s: key not found", __func__); 366 goto done; 367 } 368 /* We have this key, free it. */ 369 if (idtab->nentries < 1) 370 fatal("%s: internal error: nentries %d", 371 __func__, idtab->nentries); 372 TAILQ_REMOVE(&idtab->idlist, id, next); 373 free_identity(id); 374 idtab->nentries--; 375 sshkey_free(key); 376 success = 1; 377 done: 378 send_status(e, success); 379 } 380 381 static void 382 process_remove_all_identities(SocketEntry *e) 383 { 384 Identity *id; 385 386 /* Loop over all identities and clear the keys. */ 387 for (id = TAILQ_FIRST(&idtab->idlist); id; 388 id = TAILQ_FIRST(&idtab->idlist)) { 389 TAILQ_REMOVE(&idtab->idlist, id, next); 390 free_identity(id); 391 } 392 393 /* Mark that there are no identities. */ 394 idtab->nentries = 0; 395 396 /* Send success. */ 397 send_status(e, 1); 398 } 399 400 /* removes expired keys and returns number of seconds until the next expiry */ 401 static time_t 402 reaper(void) 403 { 404 time_t deadline = 0, now = monotime(); 405 Identity *id, *nxt; 406 407 for (id = TAILQ_FIRST(&idtab->idlist); id; id = nxt) { 408 nxt = TAILQ_NEXT(id, next); 409 if (id->death == 0) 410 continue; 411 if (now >= id->death) { 412 debug("expiring key '%s'", id->comment); 413 TAILQ_REMOVE(&idtab->idlist, id, next); 414 free_identity(id); 415 idtab->nentries--; 416 } else 417 deadline = (deadline == 0) ? id->death : 418 MINIMUM(deadline, id->death); 419 } 420 if (deadline == 0 || deadline <= now) 421 return 0; 422 else 423 return (deadline - now); 424 } 425 426 static void 427 process_add_identity(SocketEntry *e) 428 { 429 Identity *id; 430 int success = 0, confirm = 0; 431 u_int seconds = 0, maxsign; 432 char *fp, *comment = NULL, *ext_name = NULL, *sk_provider = NULL; 433 char canonical_provider[PATH_MAX]; 434 time_t death = 0; 435 struct sshkey *k = NULL; 436 u_char ctype; 437 int r = SSH_ERR_INTERNAL_ERROR; 438 439 if ((r = sshkey_private_deserialize(e->request, &k)) != 0 || 440 k == NULL || 441 (r = sshbuf_get_cstring(e->request, &comment, NULL)) != 0) { 442 error("%s: decode private key: %s", __func__, ssh_err(r)); 443 goto err; 444 } 445 while (sshbuf_len(e->request)) { 446 if ((r = sshbuf_get_u8(e->request, &ctype)) != 0) { 447 error("%s: buffer error: %s", __func__, ssh_err(r)); 448 goto err; 449 } 450 switch (ctype) { 451 case SSH_AGENT_CONSTRAIN_LIFETIME: 452 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) { 453 error("%s: bad lifetime constraint: %s", 454 __func__, ssh_err(r)); 455 goto err; 456 } 457 death = monotime() + seconds; 458 break; 459 case SSH_AGENT_CONSTRAIN_CONFIRM: 460 confirm = 1; 461 break; 462 case SSH_AGENT_CONSTRAIN_MAXSIGN: 463 if ((r = sshbuf_get_u32(e->request, &maxsign)) != 0) { 464 error("%s: bad maxsign constraint: %s", 465 __func__, ssh_err(r)); 466 goto err; 467 } 468 if ((r = sshkey_enable_maxsign(k, maxsign)) != 0) { 469 error("%s: cannot enable maxsign: %s", 470 __func__, ssh_err(r)); 471 goto err; 472 } 473 break; 474 case SSH_AGENT_CONSTRAIN_EXTENSION: 475 if ((r = sshbuf_get_cstring(e->request, 476 &ext_name, NULL)) != 0) { 477 error("%s: cannot parse extension: %s", 478 __func__, ssh_err(r)); 479 goto err; 480 } 481 debug("%s: constraint ext %s", __func__, ext_name); 482 if (strcmp(ext_name, "sk-provider@openssh.com") == 0) { 483 if (sk_provider != NULL) { 484 error("%s already set", ext_name); 485 goto err; 486 } 487 if ((r = sshbuf_get_cstring(e->request, 488 &sk_provider, NULL)) != 0) { 489 error("%s: cannot parse %s: %s", 490 __func__, ext_name, ssh_err(r)); 491 goto err; 492 } 493 } else { 494 error("%s: unsupported constraint \"%s\"", 495 __func__, ext_name); 496 goto err; 497 } 498 free(ext_name); 499 break; 500 default: 501 error("%s: Unknown constraint %d", __func__, ctype); 502 err: 503 free(sk_provider); 504 free(ext_name); 505 sshbuf_reset(e->request); 506 free(comment); 507 sshkey_free(k); 508 goto send; 509 } 510 } 511 if (sk_provider != NULL) { 512 if (!sshkey_is_sk(k)) { 513 error("Cannot add provider: %s is not an " 514 "authenticator-hosted key", sshkey_type(k)); 515 free(sk_provider); 516 goto send; 517 } 518 if (strcasecmp(sk_provider, "internal") == 0) { 519 debug("%s: internal provider", __func__); 520 } else { 521 if (realpath(sk_provider, canonical_provider) == NULL) { 522 verbose("failed provider \"%.100s\": " 523 "realpath: %s", sk_provider, 524 strerror(errno)); 525 free(sk_provider); 526 goto send; 527 } 528 free(sk_provider); 529 sk_provider = xstrdup(canonical_provider); 530 if (match_pattern_list(sk_provider, 531 provider_whitelist, 0) != 1) { 532 error("Refusing add key: " 533 "provider %s not whitelisted", sk_provider); 534 free(sk_provider); 535 goto send; 536 } 537 } 538 } 539 if ((r = sshkey_shield_private(k)) != 0) { 540 error("%s: shield private key: %s", __func__, ssh_err(r)); 541 goto err; 542 } 543 544 success = 1; 545 if (lifetime && !death) 546 death = monotime() + lifetime; 547 if ((id = lookup_identity(k)) == NULL) { 548 id = xcalloc(1, sizeof(Identity)); 549 TAILQ_INSERT_TAIL(&idtab->idlist, id, next); 550 /* Increment the number of identities. */ 551 idtab->nentries++; 552 } else { 553 /* key state might have been updated */ 554 sshkey_free(id->key); 555 free(id->comment); 556 free(id->sk_provider); 557 } 558 id->key = k; 559 id->comment = comment; 560 id->death = death; 561 id->confirm = confirm; 562 id->sk_provider = sk_provider; 563 564 if ((fp = sshkey_fingerprint(k, SSH_FP_HASH_DEFAULT, 565 SSH_FP_DEFAULT)) == NULL) 566 fatal("%s: sshkey_fingerprint failed", __func__); 567 debug("%s: add %s %s \"%.100s\" (life: %u) (confirm: %u) " 568 "(provider: %s)", __func__, sshkey_ssh_name(k), fp, comment, 569 seconds, confirm, sk_provider == NULL ? "none" : sk_provider); 570 free(fp); 571 send: 572 send_status(e, success); 573 } 574 575 /* XXX todo: encrypt sensitive data with passphrase */ 576 static void 577 process_lock_agent(SocketEntry *e, int lock) 578 { 579 int r, success = 0, delay; 580 char *passwd; 581 u_char passwdhash[LOCK_SIZE]; 582 static u_int fail_count = 0; 583 size_t pwlen; 584 585 /* 586 * This is deliberately fatal: the user has requested that we lock, 587 * but we can't parse their request properly. The only safe thing to 588 * do is abort. 589 */ 590 if ((r = sshbuf_get_cstring(e->request, &passwd, &pwlen)) != 0) 591 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 592 if (pwlen == 0) { 593 debug("empty password not supported"); 594 } else if (locked && !lock) { 595 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 596 passwdhash, sizeof(passwdhash), LOCK_ROUNDS) < 0) 597 fatal("bcrypt_pbkdf"); 598 if (timingsafe_bcmp(passwdhash, lock_pwhash, LOCK_SIZE) == 0) { 599 debug("agent unlocked"); 600 locked = 0; 601 fail_count = 0; 602 explicit_bzero(lock_pwhash, sizeof(lock_pwhash)); 603 success = 1; 604 } else { 605 /* delay in 0.1s increments up to 10s */ 606 if (fail_count < 100) 607 fail_count++; 608 delay = 100000 * fail_count; 609 debug("unlock failed, delaying %0.1lf seconds", 610 (double)delay/1000000); 611 usleep(delay); 612 } 613 explicit_bzero(passwdhash, sizeof(passwdhash)); 614 } else if (!locked && lock) { 615 debug("agent locked"); 616 locked = 1; 617 arc4random_buf(lock_salt, sizeof(lock_salt)); 618 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 619 lock_pwhash, sizeof(lock_pwhash), LOCK_ROUNDS) < 0) 620 fatal("bcrypt_pbkdf"); 621 success = 1; 622 } 623 freezero(passwd, pwlen); 624 send_status(e, success); 625 } 626 627 static void 628 no_identities(SocketEntry *e) 629 { 630 struct sshbuf *msg; 631 int r; 632 633 if ((msg = sshbuf_new()) == NULL) 634 fatal("%s: sshbuf_new failed", __func__); 635 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 636 (r = sshbuf_put_u32(msg, 0)) != 0 || 637 (r = sshbuf_put_stringb(e->output, msg)) != 0) 638 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 639 sshbuf_free(msg); 640 } 641 642 #ifdef ENABLE_PKCS11 643 static void 644 process_add_smartcard_key(SocketEntry *e) 645 { 646 char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX]; 647 char **comments = NULL; 648 int r, i, count = 0, success = 0, confirm = 0; 649 u_int seconds; 650 time_t death = 0; 651 u_char type; 652 struct sshkey **keys = NULL, *k; 653 Identity *id; 654 655 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 656 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) { 657 error("%s: buffer error: %s", __func__, ssh_err(r)); 658 goto send; 659 } 660 661 while (sshbuf_len(e->request)) { 662 if ((r = sshbuf_get_u8(e->request, &type)) != 0) { 663 error("%s: buffer error: %s", __func__, ssh_err(r)); 664 goto send; 665 } 666 switch (type) { 667 case SSH_AGENT_CONSTRAIN_LIFETIME: 668 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) { 669 error("%s: buffer error: %s", 670 __func__, ssh_err(r)); 671 goto send; 672 } 673 death = monotime() + seconds; 674 break; 675 case SSH_AGENT_CONSTRAIN_CONFIRM: 676 confirm = 1; 677 break; 678 default: 679 error("%s: Unknown constraint type %d", __func__, type); 680 goto send; 681 } 682 } 683 if (realpath(provider, canonical_provider) == NULL) { 684 verbose("failed PKCS#11 add of \"%.100s\": realpath: %s", 685 provider, strerror(errno)); 686 goto send; 687 } 688 if (match_pattern_list(canonical_provider, provider_whitelist, 0) != 1) { 689 verbose("refusing PKCS#11 add of \"%.100s\": " 690 "provider not whitelisted", canonical_provider); 691 goto send; 692 } 693 debug("%s: add %.100s", __func__, canonical_provider); 694 if (lifetime && !death) 695 death = monotime() + lifetime; 696 697 count = pkcs11_add_provider(canonical_provider, pin, &keys, &comments); 698 for (i = 0; i < count; i++) { 699 k = keys[i]; 700 if (lookup_identity(k) == NULL) { 701 id = xcalloc(1, sizeof(Identity)); 702 id->key = k; 703 keys[i] = NULL; /* transferred */ 704 id->provider = xstrdup(canonical_provider); 705 if (*comments[i] != '\0') { 706 id->comment = comments[i]; 707 comments[i] = NULL; /* transferred */ 708 } else { 709 id->comment = xstrdup(canonical_provider); 710 } 711 id->death = death; 712 id->confirm = confirm; 713 TAILQ_INSERT_TAIL(&idtab->idlist, id, next); 714 idtab->nentries++; 715 success = 1; 716 } 717 sshkey_free(keys[i]); 718 free(comments[i]); 719 } 720 send: 721 free(pin); 722 free(provider); 723 free(keys); 724 free(comments); 725 send_status(e, success); 726 } 727 728 static void 729 process_remove_smartcard_key(SocketEntry *e) 730 { 731 char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX]; 732 int r, success = 0; 733 Identity *id, *nxt; 734 735 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 736 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) { 737 error("%s: buffer error: %s", __func__, ssh_err(r)); 738 goto send; 739 } 740 free(pin); 741 742 if (realpath(provider, canonical_provider) == NULL) { 743 verbose("failed PKCS#11 add of \"%.100s\": realpath: %s", 744 provider, strerror(errno)); 745 goto send; 746 } 747 748 debug("%s: remove %.100s", __func__, canonical_provider); 749 for (id = TAILQ_FIRST(&idtab->idlist); id; id = nxt) { 750 nxt = TAILQ_NEXT(id, next); 751 /* Skip file--based keys */ 752 if (id->provider == NULL) 753 continue; 754 if (!strcmp(canonical_provider, id->provider)) { 755 TAILQ_REMOVE(&idtab->idlist, id, next); 756 free_identity(id); 757 idtab->nentries--; 758 } 759 } 760 if (pkcs11_del_provider(canonical_provider) == 0) 761 success = 1; 762 else 763 error("%s: pkcs11_del_provider failed", __func__); 764 send: 765 free(provider); 766 send_status(e, success); 767 } 768 #endif /* ENABLE_PKCS11 */ 769 770 /* dispatch incoming messages */ 771 772 static int 773 process_message(u_int socknum) 774 { 775 u_int msg_len; 776 u_char type; 777 const u_char *cp; 778 int r; 779 SocketEntry *e; 780 781 if (socknum >= sockets_alloc) { 782 fatal("%s: socket number %u >= allocated %u", 783 __func__, socknum, sockets_alloc); 784 } 785 e = &sockets[socknum]; 786 787 if (sshbuf_len(e->input) < 5) 788 return 0; /* Incomplete message header. */ 789 cp = sshbuf_ptr(e->input); 790 msg_len = PEEK_U32(cp); 791 if (msg_len > AGENT_MAX_LEN) { 792 debug("%s: socket %u (fd=%d) message too long %u > %u", 793 __func__, socknum, e->fd, msg_len, AGENT_MAX_LEN); 794 return -1; 795 } 796 if (sshbuf_len(e->input) < msg_len + 4) 797 return 0; /* Incomplete message body. */ 798 799 /* move the current input to e->request */ 800 sshbuf_reset(e->request); 801 if ((r = sshbuf_get_stringb(e->input, e->request)) != 0 || 802 (r = sshbuf_get_u8(e->request, &type)) != 0) { 803 if (r == SSH_ERR_MESSAGE_INCOMPLETE || 804 r == SSH_ERR_STRING_TOO_LARGE) { 805 debug("%s: buffer error: %s", __func__, ssh_err(r)); 806 return -1; 807 } 808 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 809 } 810 811 debug("%s: socket %u (fd=%d) type %d", __func__, socknum, e->fd, type); 812 813 /* check whether agent is locked */ 814 if (locked && type != SSH_AGENTC_UNLOCK) { 815 sshbuf_reset(e->request); 816 switch (type) { 817 case SSH2_AGENTC_REQUEST_IDENTITIES: 818 /* send empty lists */ 819 no_identities(e); 820 break; 821 default: 822 /* send a fail message for all other request types */ 823 send_status(e, 0); 824 } 825 return 0; 826 } 827 828 switch (type) { 829 case SSH_AGENTC_LOCK: 830 case SSH_AGENTC_UNLOCK: 831 process_lock_agent(e, type == SSH_AGENTC_LOCK); 832 break; 833 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 834 process_remove_all_identities(e); /* safe for !WITH_SSH1 */ 835 break; 836 /* ssh2 */ 837 case SSH2_AGENTC_SIGN_REQUEST: 838 process_sign_request2(e); 839 break; 840 case SSH2_AGENTC_REQUEST_IDENTITIES: 841 process_request_identities(e); 842 break; 843 case SSH2_AGENTC_ADD_IDENTITY: 844 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 845 process_add_identity(e); 846 break; 847 case SSH2_AGENTC_REMOVE_IDENTITY: 848 process_remove_identity(e); 849 break; 850 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 851 process_remove_all_identities(e); 852 break; 853 #ifdef ENABLE_PKCS11 854 case SSH_AGENTC_ADD_SMARTCARD_KEY: 855 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 856 process_add_smartcard_key(e); 857 break; 858 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 859 process_remove_smartcard_key(e); 860 break; 861 #endif /* ENABLE_PKCS11 */ 862 default: 863 /* Unknown message. Respond with failure. */ 864 error("Unknown message %d", type); 865 sshbuf_reset(e->request); 866 send_status(e, 0); 867 break; 868 } 869 return 0; 870 } 871 872 static void 873 new_socket(sock_type type, int fd) 874 { 875 u_int i, old_alloc, new_alloc; 876 877 set_nonblock(fd); 878 879 if (fd > max_fd) 880 max_fd = fd; 881 882 for (i = 0; i < sockets_alloc; i++) 883 if (sockets[i].type == AUTH_UNUSED) { 884 sockets[i].fd = fd; 885 if ((sockets[i].input = sshbuf_new()) == NULL) 886 fatal("%s: sshbuf_new failed", __func__); 887 if ((sockets[i].output = sshbuf_new()) == NULL) 888 fatal("%s: sshbuf_new failed", __func__); 889 if ((sockets[i].request = sshbuf_new()) == NULL) 890 fatal("%s: sshbuf_new failed", __func__); 891 sockets[i].type = type; 892 return; 893 } 894 old_alloc = sockets_alloc; 895 new_alloc = sockets_alloc + 10; 896 sockets = xreallocarray(sockets, new_alloc, sizeof(sockets[0])); 897 for (i = old_alloc; i < new_alloc; i++) 898 sockets[i].type = AUTH_UNUSED; 899 sockets_alloc = new_alloc; 900 sockets[old_alloc].fd = fd; 901 if ((sockets[old_alloc].input = sshbuf_new()) == NULL) 902 fatal("%s: sshbuf_new failed", __func__); 903 if ((sockets[old_alloc].output = sshbuf_new()) == NULL) 904 fatal("%s: sshbuf_new failed", __func__); 905 if ((sockets[old_alloc].request = sshbuf_new()) == NULL) 906 fatal("%s: sshbuf_new failed", __func__); 907 sockets[old_alloc].type = type; 908 } 909 910 static int 911 handle_socket_read(u_int socknum) 912 { 913 struct sockaddr_un sunaddr; 914 socklen_t slen; 915 uid_t euid; 916 gid_t egid; 917 int fd; 918 919 slen = sizeof(sunaddr); 920 fd = accept(sockets[socknum].fd, (struct sockaddr *)&sunaddr, &slen); 921 if (fd == -1) { 922 error("accept from AUTH_SOCKET: %s", strerror(errno)); 923 return -1; 924 } 925 if (getpeereid(fd, &euid, &egid) == -1) { 926 error("getpeereid %d failed: %s", fd, strerror(errno)); 927 close(fd); 928 return -1; 929 } 930 if ((euid != 0) && (getuid() != euid)) { 931 error("uid mismatch: peer euid %u != uid %u", 932 (u_int) euid, (u_int) getuid()); 933 close(fd); 934 return -1; 935 } 936 new_socket(AUTH_CONNECTION, fd); 937 return 0; 938 } 939 940 static int 941 handle_conn_read(u_int socknum) 942 { 943 char buf[AGENT_RBUF_LEN]; 944 ssize_t len; 945 int r; 946 947 if ((len = read(sockets[socknum].fd, buf, sizeof(buf))) <= 0) { 948 if (len == -1) { 949 if (errno == EAGAIN || errno == EINTR) 950 return 0; 951 error("%s: read error on socket %u (fd %d): %s", 952 __func__, socknum, sockets[socknum].fd, 953 strerror(errno)); 954 } 955 return -1; 956 } 957 if ((r = sshbuf_put(sockets[socknum].input, buf, len)) != 0) 958 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 959 explicit_bzero(buf, sizeof(buf)); 960 process_message(socknum); 961 return 0; 962 } 963 964 static int 965 handle_conn_write(u_int socknum) 966 { 967 ssize_t len; 968 int r; 969 970 if (sshbuf_len(sockets[socknum].output) == 0) 971 return 0; /* shouldn't happen */ 972 if ((len = write(sockets[socknum].fd, 973 sshbuf_ptr(sockets[socknum].output), 974 sshbuf_len(sockets[socknum].output))) <= 0) { 975 if (len == -1) { 976 if (errno == EAGAIN || errno == EINTR) 977 return 0; 978 error("%s: read error on socket %u (fd %d): %s", 979 __func__, socknum, sockets[socknum].fd, 980 strerror(errno)); 981 } 982 return -1; 983 } 984 if ((r = sshbuf_consume(sockets[socknum].output, len)) != 0) 985 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 986 return 0; 987 } 988 989 static void 990 after_poll(struct pollfd *pfd, size_t npfd, u_int maxfds) 991 { 992 size_t i; 993 u_int socknum, activefds = npfd; 994 995 for (i = 0; i < npfd; i++) { 996 if (pfd[i].revents == 0) 997 continue; 998 /* Find sockets entry */ 999 for (socknum = 0; socknum < sockets_alloc; socknum++) { 1000 if (sockets[socknum].type != AUTH_SOCKET && 1001 sockets[socknum].type != AUTH_CONNECTION) 1002 continue; 1003 if (pfd[i].fd == sockets[socknum].fd) 1004 break; 1005 } 1006 if (socknum >= sockets_alloc) { 1007 error("%s: no socket for fd %d", __func__, pfd[i].fd); 1008 continue; 1009 } 1010 /* Process events */ 1011 switch (sockets[socknum].type) { 1012 case AUTH_SOCKET: 1013 if ((pfd[i].revents & (POLLIN|POLLERR)) == 0) 1014 break; 1015 if (npfd > maxfds) { 1016 debug3("out of fds (active %u >= limit %u); " 1017 "skipping accept", activefds, maxfds); 1018 break; 1019 } 1020 if (handle_socket_read(socknum) == 0) 1021 activefds++; 1022 break; 1023 case AUTH_CONNECTION: 1024 if ((pfd[i].revents & (POLLIN|POLLERR)) != 0 && 1025 handle_conn_read(socknum) != 0) { 1026 goto close_sock; 1027 } 1028 if ((pfd[i].revents & (POLLOUT|POLLHUP)) != 0 && 1029 handle_conn_write(socknum) != 0) { 1030 close_sock: 1031 if (activefds == 0) 1032 fatal("activefds == 0 at close_sock"); 1033 close_socket(&sockets[socknum]); 1034 activefds--; 1035 break; 1036 } 1037 break; 1038 default: 1039 break; 1040 } 1041 } 1042 } 1043 1044 static int 1045 prepare_poll(struct pollfd **pfdp, size_t *npfdp, int *timeoutp, u_int maxfds) 1046 { 1047 struct pollfd *pfd = *pfdp; 1048 size_t i, j, npfd = 0; 1049 time_t deadline; 1050 int r; 1051 1052 /* Count active sockets */ 1053 for (i = 0; i < sockets_alloc; i++) { 1054 switch (sockets[i].type) { 1055 case AUTH_SOCKET: 1056 case AUTH_CONNECTION: 1057 npfd++; 1058 break; 1059 case AUTH_UNUSED: 1060 break; 1061 default: 1062 fatal("Unknown socket type %d", sockets[i].type); 1063 break; 1064 } 1065 } 1066 if (npfd != *npfdp && 1067 (pfd = recallocarray(pfd, *npfdp, npfd, sizeof(*pfd))) == NULL) 1068 fatal("%s: recallocarray failed", __func__); 1069 *pfdp = pfd; 1070 *npfdp = npfd; 1071 1072 for (i = j = 0; i < sockets_alloc; i++) { 1073 switch (sockets[i].type) { 1074 case AUTH_SOCKET: 1075 if (npfd > maxfds) { 1076 debug3("out of fds (active %zu >= limit %u); " 1077 "skipping arming listener", npfd, maxfds); 1078 break; 1079 } 1080 pfd[j].fd = sockets[i].fd; 1081 pfd[j].revents = 0; 1082 pfd[j].events = POLLIN; 1083 j++; 1084 break; 1085 case AUTH_CONNECTION: 1086 pfd[j].fd = sockets[i].fd; 1087 pfd[j].revents = 0; 1088 /* 1089 * Only prepare to read if we can handle a full-size 1090 * input read buffer and enqueue a max size reply.. 1091 */ 1092 if ((r = sshbuf_check_reserve(sockets[i].input, 1093 AGENT_RBUF_LEN)) == 0 && 1094 (r = sshbuf_check_reserve(sockets[i].output, 1095 AGENT_MAX_LEN)) == 0) 1096 pfd[j].events = POLLIN; 1097 else if (r != SSH_ERR_NO_BUFFER_SPACE) { 1098 fatal("%s: buffer error: %s", 1099 __func__, ssh_err(r)); 1100 } 1101 if (sshbuf_len(sockets[i].output) > 0) 1102 pfd[j].events |= POLLOUT; 1103 j++; 1104 break; 1105 default: 1106 break; 1107 } 1108 } 1109 deadline = reaper(); 1110 if (parent_alive_interval != 0) 1111 deadline = (deadline == 0) ? parent_alive_interval : 1112 MINIMUM(deadline, parent_alive_interval); 1113 if (deadline == 0) { 1114 *timeoutp = -1; /* INFTIM */ 1115 } else { 1116 if (deadline > INT_MAX / 1000) 1117 *timeoutp = INT_MAX / 1000; 1118 else 1119 *timeoutp = deadline * 1000; 1120 } 1121 return (1); 1122 } 1123 1124 static void 1125 cleanup_socket(void) 1126 { 1127 if (cleanup_pid != 0 && getpid() != cleanup_pid) 1128 return; 1129 debug("%s: cleanup", __func__); 1130 if (socket_name[0]) 1131 unlink(socket_name); 1132 if (socket_dir[0]) 1133 rmdir(socket_dir); 1134 } 1135 1136 void 1137 cleanup_exit(int i) 1138 { 1139 cleanup_socket(); 1140 _exit(i); 1141 } 1142 1143 /*ARGSUSED*/ 1144 static void 1145 cleanup_handler(int sig) 1146 { 1147 cleanup_socket(); 1148 #ifdef ENABLE_PKCS11 1149 pkcs11_terminate(); 1150 #endif 1151 _exit(2); 1152 } 1153 1154 static void 1155 check_parent_exists(void) 1156 { 1157 /* 1158 * If our parent has exited then getppid() will return (pid_t)1, 1159 * so testing for that should be safe. 1160 */ 1161 if (parent_pid != -1 && getppid() != parent_pid) { 1162 /* printf("Parent has died - Authentication agent exiting.\n"); */ 1163 cleanup_socket(); 1164 _exit(2); 1165 } 1166 } 1167 1168 static void 1169 usage(void) 1170 { 1171 fprintf(stderr, 1172 "usage: ssh-agent [-c | -s] [-Dd] [-a bind_address] [-E fingerprint_hash]\n" 1173 " [-P provider_whitelist] [-t life] [command [arg ...]]\n" 1174 " ssh-agent [-c | -s] -k\n"); 1175 exit(1); 1176 } 1177 1178 int 1179 main(int ac, char **av) 1180 { 1181 int c_flag = 0, d_flag = 0, D_flag = 0, k_flag = 0, s_flag = 0; 1182 int sock, fd, ch, result, saved_errno; 1183 char *shell, *format, *pidstr, *agentsocket = NULL; 1184 #ifdef HAVE_SETRLIMIT 1185 struct rlimit rlim; 1186 #endif 1187 extern int optind; 1188 extern char *optarg; 1189 pid_t pid; 1190 char pidstrbuf[1 + 3 * sizeof pid]; 1191 size_t len; 1192 mode_t prev_mask; 1193 int timeout = -1; /* INFTIM */ 1194 struct pollfd *pfd = NULL; 1195 size_t npfd = 0; 1196 u_int maxfds; 1197 1198 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1199 sanitise_stdfd(); 1200 1201 /* drop */ 1202 setegid(getgid()); 1203 setgid(getgid()); 1204 1205 platform_disable_tracing(0); /* strict=no */ 1206 1207 #ifdef RLIMIT_NOFILE 1208 if (getrlimit(RLIMIT_NOFILE, &rlim) == -1) 1209 fatal("%s: getrlimit: %s", __progname, strerror(errno)); 1210 #endif 1211 1212 __progname = ssh_get_progname(av[0]); 1213 seed_rng(); 1214 1215 while ((ch = getopt(ac, av, "cDdksE:a:P:t:")) != -1) { 1216 switch (ch) { 1217 case 'E': 1218 fingerprint_hash = ssh_digest_alg_by_name(optarg); 1219 if (fingerprint_hash == -1) 1220 fatal("Invalid hash algorithm \"%s\"", optarg); 1221 break; 1222 case 'c': 1223 if (s_flag) 1224 usage(); 1225 c_flag++; 1226 break; 1227 case 'k': 1228 k_flag++; 1229 break; 1230 case 'P': 1231 if (provider_whitelist != NULL) 1232 fatal("-P option already specified"); 1233 provider_whitelist = xstrdup(optarg); 1234 break; 1235 case 's': 1236 if (c_flag) 1237 usage(); 1238 s_flag++; 1239 break; 1240 case 'd': 1241 if (d_flag || D_flag) 1242 usage(); 1243 d_flag++; 1244 break; 1245 case 'D': 1246 if (d_flag || D_flag) 1247 usage(); 1248 D_flag++; 1249 break; 1250 case 'a': 1251 agentsocket = optarg; 1252 break; 1253 case 't': 1254 if ((lifetime = convtime(optarg)) == -1) { 1255 fprintf(stderr, "Invalid lifetime\n"); 1256 usage(); 1257 } 1258 break; 1259 default: 1260 usage(); 1261 } 1262 } 1263 ac -= optind; 1264 av += optind; 1265 1266 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag || D_flag)) 1267 usage(); 1268 1269 if (provider_whitelist == NULL) 1270 provider_whitelist = xstrdup(DEFAULT_PROVIDER_WHITELIST); 1271 1272 if (ac == 0 && !c_flag && !s_flag) { 1273 shell = getenv("SHELL"); 1274 if (shell != NULL && (len = strlen(shell)) > 2 && 1275 strncmp(shell + len - 3, "csh", 3) == 0) 1276 c_flag = 1; 1277 } 1278 if (k_flag) { 1279 const char *errstr = NULL; 1280 1281 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1282 if (pidstr == NULL) { 1283 fprintf(stderr, "%s not set, cannot kill agent\n", 1284 SSH_AGENTPID_ENV_NAME); 1285 exit(1); 1286 } 1287 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr); 1288 if (errstr) { 1289 fprintf(stderr, 1290 "%s=\"%s\", which is not a good PID: %s\n", 1291 SSH_AGENTPID_ENV_NAME, pidstr, errstr); 1292 exit(1); 1293 } 1294 if (kill(pid, SIGTERM) == -1) { 1295 perror("kill"); 1296 exit(1); 1297 } 1298 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 1299 printf(format, SSH_AUTHSOCKET_ENV_NAME); 1300 printf(format, SSH_AGENTPID_ENV_NAME); 1301 printf("echo Agent pid %ld killed;\n", (long)pid); 1302 exit(0); 1303 } 1304 1305 /* 1306 * Minimum file descriptors: 1307 * stdio (3) + listener (1) + syslog (1 maybe) + connection (1) + 1308 * a few spare for libc / stack protectors / sanitisers, etc. 1309 */ 1310 #define SSH_AGENT_MIN_FDS (3+1+1+1+4) 1311 if (rlim.rlim_cur < SSH_AGENT_MIN_FDS) 1312 fatal("%s: file descriptor rlimit %lld too low (minimum %u)", 1313 __progname, (long long)rlim.rlim_cur, SSH_AGENT_MIN_FDS); 1314 maxfds = rlim.rlim_cur - SSH_AGENT_MIN_FDS; 1315 1316 parent_pid = getpid(); 1317 1318 if (agentsocket == NULL) { 1319 /* Create private directory for agent socket */ 1320 mktemp_proto(socket_dir, sizeof(socket_dir)); 1321 if (mkdtemp(socket_dir) == NULL) { 1322 perror("mkdtemp: private socket dir"); 1323 exit(1); 1324 } 1325 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1326 (long)parent_pid); 1327 } else { 1328 /* Try to use specified agent socket */ 1329 socket_dir[0] = '\0'; 1330 strlcpy(socket_name, agentsocket, sizeof socket_name); 1331 } 1332 1333 /* 1334 * Create socket early so it will exist before command gets run from 1335 * the parent. 1336 */ 1337 prev_mask = umask(0177); 1338 sock = unix_listener(socket_name, SSH_LISTEN_BACKLOG, 0); 1339 if (sock < 0) { 1340 /* XXX - unix_listener() calls error() not perror() */ 1341 *socket_name = '\0'; /* Don't unlink any existing file */ 1342 cleanup_exit(1); 1343 } 1344 umask(prev_mask); 1345 1346 /* 1347 * Fork, and have the parent execute the command, if any, or present 1348 * the socket data. The child continues as the authentication agent. 1349 */ 1350 if (D_flag || d_flag) { 1351 log_init(__progname, 1352 d_flag ? SYSLOG_LEVEL_DEBUG3 : SYSLOG_LEVEL_INFO, 1353 SYSLOG_FACILITY_AUTH, 1); 1354 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1355 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1356 SSH_AUTHSOCKET_ENV_NAME); 1357 printf("echo Agent pid %ld;\n", (long)parent_pid); 1358 fflush(stdout); 1359 goto skip; 1360 } 1361 pid = fork(); 1362 if (pid == -1) { 1363 perror("fork"); 1364 cleanup_exit(1); 1365 } 1366 if (pid != 0) { /* Parent - execute the given command. */ 1367 close(sock); 1368 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1369 if (ac == 0) { 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(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 1374 SSH_AGENTPID_ENV_NAME); 1375 printf("echo Agent pid %ld;\n", (long)pid); 1376 exit(0); 1377 } 1378 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1379 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1380 perror("setenv"); 1381 exit(1); 1382 } 1383 execvp(av[0], av); 1384 perror(av[0]); 1385 exit(1); 1386 } 1387 /* child */ 1388 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1389 1390 if (setsid() == -1) { 1391 error("setsid: %s", strerror(errno)); 1392 cleanup_exit(1); 1393 } 1394 1395 (void)chdir("/"); 1396 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1397 /* XXX might close listen socket */ 1398 (void)dup2(fd, STDIN_FILENO); 1399 (void)dup2(fd, STDOUT_FILENO); 1400 (void)dup2(fd, STDERR_FILENO); 1401 if (fd > 2) 1402 close(fd); 1403 } 1404 1405 #ifdef HAVE_SETRLIMIT 1406 /* deny core dumps, since memory contains unencrypted private keys */ 1407 rlim.rlim_cur = rlim.rlim_max = 0; 1408 if (setrlimit(RLIMIT_CORE, &rlim) == -1) { 1409 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1410 cleanup_exit(1); 1411 } 1412 #endif 1413 1414 skip: 1415 1416 cleanup_pid = getpid(); 1417 1418 #ifdef ENABLE_PKCS11 1419 pkcs11_init(0); 1420 #endif 1421 new_socket(AUTH_SOCKET, sock); 1422 if (ac > 0) 1423 parent_alive_interval = 10; 1424 idtab_init(); 1425 ssh_signal(SIGPIPE, SIG_IGN); 1426 ssh_signal(SIGINT, (d_flag | D_flag) ? cleanup_handler : SIG_IGN); 1427 ssh_signal(SIGHUP, cleanup_handler); 1428 ssh_signal(SIGTERM, cleanup_handler); 1429 1430 if (pledge("stdio rpath cpath unix id proc exec", NULL) == -1) 1431 fatal("%s: pledge: %s", __progname, strerror(errno)); 1432 platform_pledge_agent(); 1433 1434 while (1) { 1435 prepare_poll(&pfd, &npfd, &timeout, maxfds); 1436 result = poll(pfd, npfd, timeout); 1437 saved_errno = errno; 1438 if (parent_alive_interval != 0) 1439 check_parent_exists(); 1440 (void) reaper(); /* remove expired keys */ 1441 if (result == -1) { 1442 if (saved_errno == EINTR) 1443 continue; 1444 fatal("poll: %s", strerror(saved_errno)); 1445 } else if (result > 0) 1446 after_poll(pfd, npfd, maxfds); 1447 } 1448 /* NOTREACHED */ 1449 } 1450