1 /* $NetBSD: ssh-agent.c,v 1.29 2020/05/28 17:05:49 christos Exp $ */ 2 /* $OpenBSD: ssh-agent.c,v 1.257 2020/03/06 18:28:27 markus 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 1.29 2020/05/28 17:05:49 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 = 0, 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 freezero(passwd, pwlen); 616 send_status(e, success); 617 } 618 619 static void 620 no_identities(SocketEntry *e) 621 { 622 struct sshbuf *msg; 623 int r; 624 625 if ((msg = sshbuf_new()) == NULL) 626 fatal("%s: sshbuf_new failed", __func__); 627 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 628 (r = sshbuf_put_u32(msg, 0)) != 0 || 629 (r = sshbuf_put_stringb(e->output, msg)) != 0) 630 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 631 sshbuf_free(msg); 632 } 633 634 #ifdef ENABLE_PKCS11 635 static void 636 process_add_smartcard_key(SocketEntry *e) 637 { 638 char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX]; 639 char **comments = NULL; 640 int r, i, count = 0, success = 0, confirm = 0; 641 u_int seconds; 642 time_t death = 0; 643 u_char type; 644 struct sshkey **keys = NULL, *k; 645 Identity *id; 646 647 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 648 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) { 649 error("%s: buffer error: %s", __func__, ssh_err(r)); 650 goto send; 651 } 652 653 while (sshbuf_len(e->request)) { 654 if ((r = sshbuf_get_u8(e->request, &type)) != 0) { 655 error("%s: buffer error: %s", __func__, ssh_err(r)); 656 goto send; 657 } 658 switch (type) { 659 case SSH_AGENT_CONSTRAIN_LIFETIME: 660 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) { 661 error("%s: buffer error: %s", 662 __func__, ssh_err(r)); 663 goto send; 664 } 665 death = monotime() + seconds; 666 break; 667 case SSH_AGENT_CONSTRAIN_CONFIRM: 668 confirm = 1; 669 break; 670 default: 671 error("%s: Unknown constraint type %d", __func__, type); 672 goto send; 673 } 674 } 675 if (realpath(provider, canonical_provider) == NULL) { 676 verbose("failed PKCS#11 add of \"%.100s\": realpath: %s", 677 provider, strerror(errno)); 678 goto send; 679 } 680 if (match_pattern_list(canonical_provider, provider_whitelist, 0) != 1) { 681 verbose("refusing PKCS#11 add of \"%.100s\": " 682 "provider not whitelisted", canonical_provider); 683 goto send; 684 } 685 debug("%s: add %.100s", __func__, canonical_provider); 686 if (lifetime && !death) 687 death = monotime() + lifetime; 688 689 count = pkcs11_add_provider(canonical_provider, pin, &keys, &comments); 690 for (i = 0; i < count; i++) { 691 k = keys[i]; 692 if (lookup_identity(k) == NULL) { 693 id = xcalloc(1, sizeof(Identity)); 694 id->key = k; 695 keys[i] = NULL; /* transferred */ 696 id->provider = xstrdup(canonical_provider); 697 if (*comments[i] != '\0') { 698 id->comment = comments[i]; 699 comments[i] = NULL; /* transferred */ 700 } else { 701 id->comment = xstrdup(canonical_provider); 702 } 703 id->death = death; 704 id->confirm = confirm; 705 TAILQ_INSERT_TAIL(&idtab->idlist, id, next); 706 idtab->nentries++; 707 success = 1; 708 } 709 sshkey_free(keys[i]); 710 free(comments[i]); 711 } 712 send: 713 free(pin); 714 free(provider); 715 free(keys); 716 free(comments); 717 send_status(e, success); 718 } 719 720 static void 721 process_remove_smartcard_key(SocketEntry *e) 722 { 723 char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX]; 724 int r, success = 0; 725 Identity *id, *nxt; 726 727 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 728 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) { 729 error("%s: buffer error: %s", __func__, ssh_err(r)); 730 goto send; 731 } 732 free(pin); 733 734 if (realpath(provider, canonical_provider) == NULL) { 735 verbose("failed PKCS#11 add of \"%.100s\": realpath: %s", 736 provider, strerror(errno)); 737 goto send; 738 } 739 740 debug("%s: remove %.100s", __func__, canonical_provider); 741 for (id = TAILQ_FIRST(&idtab->idlist); id; id = nxt) { 742 nxt = TAILQ_NEXT(id, next); 743 /* Skip file--based keys */ 744 if (id->provider == NULL) 745 continue; 746 if (!strcmp(canonical_provider, id->provider)) { 747 TAILQ_REMOVE(&idtab->idlist, id, next); 748 free_identity(id); 749 idtab->nentries--; 750 } 751 } 752 if (pkcs11_del_provider(canonical_provider) == 0) 753 success = 1; 754 else 755 error("%s: pkcs11_del_provider failed", __func__); 756 send: 757 free(provider); 758 send_status(e, success); 759 } 760 #endif /* ENABLE_PKCS11 */ 761 762 /* dispatch incoming messages */ 763 764 static int 765 process_message(u_int socknum) 766 { 767 u_int msg_len; 768 u_char type; 769 const u_char *cp; 770 int r; 771 SocketEntry *e; 772 773 if (socknum >= sockets_alloc) { 774 fatal("%s: socket number %u >= allocated %u", 775 __func__, socknum, sockets_alloc); 776 } 777 e = &sockets[socknum]; 778 779 if (sshbuf_len(e->input) < 5) 780 return 0; /* Incomplete message header. */ 781 cp = sshbuf_ptr(e->input); 782 msg_len = PEEK_U32(cp); 783 if (msg_len > AGENT_MAX_LEN) { 784 debug("%s: socket %u (fd=%d) message too long %u > %u", 785 __func__, socknum, e->fd, msg_len, AGENT_MAX_LEN); 786 return -1; 787 } 788 if (sshbuf_len(e->input) < msg_len + 4) 789 return 0; /* Incomplete message body. */ 790 791 /* move the current input to e->request */ 792 sshbuf_reset(e->request); 793 if ((r = sshbuf_get_stringb(e->input, e->request)) != 0 || 794 (r = sshbuf_get_u8(e->request, &type)) != 0) { 795 if (r == SSH_ERR_MESSAGE_INCOMPLETE || 796 r == SSH_ERR_STRING_TOO_LARGE) { 797 debug("%s: buffer error: %s", __func__, ssh_err(r)); 798 return -1; 799 } 800 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 801 } 802 803 debug("%s: socket %u (fd=%d) type %d", __func__, socknum, e->fd, type); 804 805 /* check whether agent is locked */ 806 if (locked && type != SSH_AGENTC_UNLOCK) { 807 sshbuf_reset(e->request); 808 switch (type) { 809 case SSH2_AGENTC_REQUEST_IDENTITIES: 810 /* send empty lists */ 811 no_identities(e); 812 break; 813 default: 814 /* send a fail message for all other request types */ 815 send_status(e, 0); 816 } 817 return 0; 818 } 819 820 switch (type) { 821 case SSH_AGENTC_LOCK: 822 case SSH_AGENTC_UNLOCK: 823 process_lock_agent(e, type == SSH_AGENTC_LOCK); 824 break; 825 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 826 process_remove_all_identities(e); /* safe for !WITH_SSH1 */ 827 break; 828 /* ssh2 */ 829 case SSH2_AGENTC_SIGN_REQUEST: 830 process_sign_request2(e); 831 break; 832 case SSH2_AGENTC_REQUEST_IDENTITIES: 833 process_request_identities(e); 834 break; 835 case SSH2_AGENTC_ADD_IDENTITY: 836 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 837 process_add_identity(e); 838 break; 839 case SSH2_AGENTC_REMOVE_IDENTITY: 840 process_remove_identity(e); 841 break; 842 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 843 process_remove_all_identities(e); 844 break; 845 #ifdef ENABLE_PKCS11 846 case SSH_AGENTC_ADD_SMARTCARD_KEY: 847 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 848 process_add_smartcard_key(e); 849 break; 850 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 851 process_remove_smartcard_key(e); 852 break; 853 #endif /* ENABLE_PKCS11 */ 854 default: 855 /* Unknown message. Respond with failure. */ 856 error("Unknown message %d", type); 857 sshbuf_reset(e->request); 858 send_status(e, 0); 859 break; 860 } 861 return 0; 862 } 863 864 static void 865 new_socket(sock_type type, int fd) 866 { 867 u_int i, old_alloc, new_alloc; 868 869 set_nonblock(fd); 870 871 if (fd > max_fd) 872 max_fd = fd; 873 874 for (i = 0; i < sockets_alloc; i++) 875 if (sockets[i].type == AUTH_UNUSED) { 876 sockets[i].fd = fd; 877 if ((sockets[i].input = sshbuf_new()) == NULL) 878 fatal("%s: sshbuf_new failed", __func__); 879 if ((sockets[i].output = sshbuf_new()) == NULL) 880 fatal("%s: sshbuf_new failed", __func__); 881 if ((sockets[i].request = sshbuf_new()) == NULL) 882 fatal("%s: sshbuf_new failed", __func__); 883 sockets[i].type = type; 884 return; 885 } 886 old_alloc = sockets_alloc; 887 new_alloc = sockets_alloc + 10; 888 sockets = xreallocarray(sockets, new_alloc, sizeof(sockets[0])); 889 for (i = old_alloc; i < new_alloc; i++) 890 sockets[i].type = AUTH_UNUSED; 891 sockets_alloc = new_alloc; 892 sockets[old_alloc].fd = fd; 893 if ((sockets[old_alloc].input = sshbuf_new()) == NULL) 894 fatal("%s: sshbuf_new failed", __func__); 895 if ((sockets[old_alloc].output = sshbuf_new()) == NULL) 896 fatal("%s: sshbuf_new failed", __func__); 897 if ((sockets[old_alloc].request = sshbuf_new()) == NULL) 898 fatal("%s: sshbuf_new failed", __func__); 899 sockets[old_alloc].type = type; 900 } 901 902 static int 903 handle_socket_read(u_int socknum) 904 { 905 struct sockaddr_un sunaddr; 906 socklen_t slen; 907 uid_t euid; 908 gid_t egid; 909 int fd; 910 911 slen = sizeof(sunaddr); 912 fd = accept(sockets[socknum].fd, (struct sockaddr *)&sunaddr, &slen); 913 if (fd == -1) { 914 error("accept from AUTH_SOCKET: %s", strerror(errno)); 915 return -1; 916 } 917 if (getpeereid(fd, &euid, &egid) == -1) { 918 error("getpeereid %d failed: %s", fd, strerror(errno)); 919 close(fd); 920 return -1; 921 } 922 if ((euid != 0) && (getuid() != euid)) { 923 error("uid mismatch: peer euid %u != uid %u", 924 (u_int) euid, (u_int) getuid()); 925 close(fd); 926 return -1; 927 } 928 new_socket(AUTH_CONNECTION, fd); 929 return 0; 930 } 931 932 static int 933 handle_conn_read(u_int socknum) 934 { 935 char buf[AGENT_RBUF_LEN]; 936 ssize_t len; 937 int r; 938 939 if ((len = read(sockets[socknum].fd, buf, sizeof(buf))) <= 0) { 940 if (len == -1) { 941 if (errno == EAGAIN || errno == EINTR) 942 return 0; 943 error("%s: read error on socket %u (fd %d): %s", 944 __func__, socknum, sockets[socknum].fd, 945 strerror(errno)); 946 } 947 return -1; 948 } 949 if ((r = sshbuf_put(sockets[socknum].input, buf, len)) != 0) 950 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 951 explicit_bzero(buf, sizeof(buf)); 952 process_message(socknum); 953 return 0; 954 } 955 956 static int 957 handle_conn_write(u_int socknum) 958 { 959 ssize_t len; 960 int r; 961 962 if (sshbuf_len(sockets[socknum].output) == 0) 963 return 0; /* shouldn't happen */ 964 if ((len = write(sockets[socknum].fd, 965 sshbuf_ptr(sockets[socknum].output), 966 sshbuf_len(sockets[socknum].output))) <= 0) { 967 if (len == -1) { 968 if (errno == EAGAIN || errno == EINTR) 969 return 0; 970 error("%s: read error on socket %u (fd %d): %s", 971 __func__, socknum, sockets[socknum].fd, 972 strerror(errno)); 973 } 974 return -1; 975 } 976 if ((r = sshbuf_consume(sockets[socknum].output, len)) != 0) 977 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 978 return 0; 979 } 980 981 static void 982 after_poll(struct pollfd *pfd, size_t npfd, u_int maxfds) 983 { 984 size_t i; 985 u_int socknum, activefds = npfd; 986 987 for (i = 0; i < npfd; i++) { 988 if (pfd[i].revents == 0) 989 continue; 990 /* Find sockets entry */ 991 for (socknum = 0; socknum < sockets_alloc; socknum++) { 992 if (sockets[socknum].type != AUTH_SOCKET && 993 sockets[socknum].type != AUTH_CONNECTION) 994 continue; 995 if (pfd[i].fd == sockets[socknum].fd) 996 break; 997 } 998 if (socknum >= sockets_alloc) { 999 error("%s: no socket for fd %d", __func__, pfd[i].fd); 1000 continue; 1001 } 1002 /* Process events */ 1003 switch (sockets[socknum].type) { 1004 case AUTH_SOCKET: 1005 if ((pfd[i].revents & (POLLIN|POLLERR)) == 0) 1006 break; 1007 if (npfd > maxfds) { 1008 debug3("out of fds (active %u >= limit %u); " 1009 "skipping accept", activefds, maxfds); 1010 break; 1011 } 1012 if (handle_socket_read(socknum) == 0) 1013 activefds++; 1014 break; 1015 case AUTH_CONNECTION: 1016 if ((pfd[i].revents & (POLLIN|POLLERR)) != 0 && 1017 handle_conn_read(socknum) != 0) { 1018 goto close_sock; 1019 } 1020 if ((pfd[i].revents & (POLLOUT|POLLHUP)) != 0 && 1021 handle_conn_write(socknum) != 0) { 1022 close_sock: 1023 if (activefds == 0) 1024 fatal("activefds == 0 at close_sock"); 1025 close_socket(&sockets[socknum]); 1026 activefds--; 1027 break; 1028 } 1029 break; 1030 default: 1031 break; 1032 } 1033 } 1034 } 1035 1036 static int 1037 prepare_poll(struct pollfd **pfdp, size_t *npfdp, int *timeoutp, u_int maxfds) 1038 { 1039 struct pollfd *pfd = *pfdp; 1040 size_t i, j, npfd = 0; 1041 time_t deadline; 1042 int r; 1043 1044 /* Count active sockets */ 1045 for (i = 0; i < sockets_alloc; i++) { 1046 switch (sockets[i].type) { 1047 case AUTH_SOCKET: 1048 case AUTH_CONNECTION: 1049 npfd++; 1050 break; 1051 case AUTH_UNUSED: 1052 break; 1053 default: 1054 fatal("Unknown socket type %d", sockets[i].type); 1055 break; 1056 } 1057 } 1058 if (npfd != *npfdp && 1059 (pfd = recallocarray(pfd, *npfdp, npfd, sizeof(*pfd))) == NULL) 1060 fatal("%s: recallocarray failed", __func__); 1061 *pfdp = pfd; 1062 *npfdp = npfd; 1063 1064 for (i = j = 0; i < sockets_alloc; i++) { 1065 switch (sockets[i].type) { 1066 case AUTH_SOCKET: 1067 if (npfd > maxfds) { 1068 debug3("out of fds (active %zu >= limit %u); " 1069 "skipping arming listener", npfd, maxfds); 1070 break; 1071 } 1072 pfd[j].fd = sockets[i].fd; 1073 pfd[j].revents = 0; 1074 pfd[j].events = POLLIN; 1075 j++; 1076 break; 1077 case AUTH_CONNECTION: 1078 pfd[j].fd = sockets[i].fd; 1079 pfd[j].revents = 0; 1080 /* 1081 * Only prepare to read if we can handle a full-size 1082 * input read buffer and enqueue a max size reply.. 1083 */ 1084 if ((r = sshbuf_check_reserve(sockets[i].input, 1085 AGENT_RBUF_LEN)) == 0 && 1086 (r = sshbuf_check_reserve(sockets[i].output, 1087 AGENT_MAX_LEN)) == 0) 1088 pfd[j].events = POLLIN; 1089 else if (r != SSH_ERR_NO_BUFFER_SPACE) { 1090 fatal("%s: buffer error: %s", 1091 __func__, ssh_err(r)); 1092 } 1093 if (sshbuf_len(sockets[i].output) > 0) 1094 pfd[j].events |= POLLOUT; 1095 j++; 1096 break; 1097 default: 1098 break; 1099 } 1100 } 1101 deadline = reaper(); 1102 if (parent_alive_interval != 0) 1103 deadline = (deadline == 0) ? parent_alive_interval : 1104 MINIMUM(deadline, parent_alive_interval); 1105 if (deadline == 0) { 1106 *timeoutp = -1; /* INFTIM */ 1107 } else { 1108 if (deadline > INT_MAX / 1000) 1109 *timeoutp = INT_MAX / 1000; 1110 else 1111 *timeoutp = deadline * 1000; 1112 } 1113 return (1); 1114 } 1115 1116 static void 1117 cleanup_socket(void) 1118 { 1119 if (cleanup_pid != 0 && getpid() != cleanup_pid) 1120 return; 1121 debug("%s: cleanup", __func__); 1122 if (socket_name[0]) 1123 unlink(socket_name); 1124 if (socket_dir[0]) 1125 rmdir(socket_dir); 1126 } 1127 1128 void 1129 cleanup_exit(int i) 1130 { 1131 cleanup_socket(); 1132 _exit(i); 1133 } 1134 1135 /*ARGSUSED*/ 1136 __dead static void 1137 cleanup_handler(int sig) 1138 { 1139 cleanup_socket(); 1140 #ifdef ENABLE_PKCS11 1141 pkcs11_terminate(); 1142 #endif 1143 _exit(2); 1144 } 1145 1146 static void 1147 check_parent_exists(void) 1148 { 1149 /* 1150 * If our parent has exited then getppid() will return (pid_t)1, 1151 * so testing for that should be safe. 1152 */ 1153 if (parent_pid != -1 && getppid() != parent_pid) { 1154 /* printf("Parent has died - Authentication agent exiting.\n"); */ 1155 cleanup_socket(); 1156 _exit(2); 1157 } 1158 } 1159 1160 __dead static void 1161 usage(void) 1162 { 1163 fprintf(stderr, 1164 "usage: ssh-agent [-c | -s] [-Dd] [-a bind_address] [-E fingerprint_hash]\n" 1165 " [-P provider_whitelist] [-t life] [command [arg ...]]\n" 1166 " ssh-agent [-c | -s] -k\n"); 1167 exit(1); 1168 } 1169 1170 static void 1171 csh_setenv(const char *name, const char *value) 1172 { 1173 printf("setenv %s %s;\n", name, value); 1174 } 1175 1176 static void 1177 csh_unsetenv(const char *name) 1178 { 1179 printf("unsetenv %s;\n", name); 1180 } 1181 1182 static void 1183 sh_setenv(const char *name, const char *value) 1184 { 1185 printf("%s=%s; export %s;\n", name, value, name); 1186 } 1187 1188 static void 1189 sh_unsetenv(const char *name) 1190 { 1191 printf("unset %s;\n", name); 1192 } 1193 int 1194 main(int ac, char **av) 1195 { 1196 int c_flag = 0, d_flag = 0, D_flag = 0, k_flag = 0, s_flag = 0; 1197 int sock, fd, ch, result, saved_errno; 1198 char *shell, *pidstr, *agentsocket = NULL; 1199 struct rlimit rlim; 1200 void (*f_setenv)(const char *, const char *); 1201 void (*f_unsetenv)(const char *); 1202 extern int optind; 1203 extern char *optarg; 1204 pid_t pid; 1205 char pidstrbuf[1 + 3 * sizeof pid]; 1206 size_t len; 1207 mode_t prev_mask; 1208 int timeout = -1; /* INFTIM */ 1209 struct pollfd *pfd = NULL; 1210 size_t npfd = 0; 1211 u_int maxfds; 1212 1213 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1214 sanitise_stdfd(); 1215 1216 /* drop */ 1217 setegid(getgid()); 1218 setgid(getgid()); 1219 1220 if (getrlimit(RLIMIT_NOFILE, &rlim) == -1) 1221 fatal("%s: getrlimit: %s", __progname, strerror(errno)); 1222 1223 #ifdef WITH_OPENSSL 1224 OpenSSL_add_all_algorithms(); 1225 #endif 1226 1227 while ((ch = getopt(ac, av, "cDdksE:a:P:t:")) != -1) { 1228 switch (ch) { 1229 case 'E': 1230 fingerprint_hash = ssh_digest_alg_by_name(optarg); 1231 if (fingerprint_hash == -1) 1232 fatal("Invalid hash algorithm \"%s\"", optarg); 1233 break; 1234 case 'c': 1235 if (s_flag) 1236 usage(); 1237 c_flag++; 1238 break; 1239 case 'k': 1240 k_flag++; 1241 break; 1242 case 'P': 1243 if (provider_whitelist != NULL) 1244 fatal("-P option already specified"); 1245 provider_whitelist = xstrdup(optarg); 1246 break; 1247 case 's': 1248 if (c_flag) 1249 usage(); 1250 s_flag++; 1251 break; 1252 case 'd': 1253 if (d_flag || D_flag) 1254 usage(); 1255 d_flag++; 1256 break; 1257 case 'D': 1258 if (d_flag || D_flag) 1259 usage(); 1260 D_flag++; 1261 break; 1262 case 'a': 1263 agentsocket = optarg; 1264 break; 1265 case 't': 1266 if ((lifetime = convtime(optarg)) == -1) { 1267 fprintf(stderr, "Invalid lifetime\n"); 1268 usage(); 1269 } 1270 break; 1271 default: 1272 usage(); 1273 } 1274 } 1275 ac -= optind; 1276 av += optind; 1277 1278 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag || D_flag)) 1279 usage(); 1280 1281 if (provider_whitelist == NULL) 1282 provider_whitelist = xstrdup(DEFAULT_PROVIDER_WHITELIST); 1283 1284 if (ac == 0 && !c_flag && !s_flag) { 1285 shell = getenv("SHELL"); 1286 if (shell != NULL && (len = strlen(shell)) > 2 && 1287 strncmp(shell + len - 3, "csh", 3) == 0) 1288 c_flag = 1; 1289 } 1290 if (c_flag) { 1291 f_setenv = csh_setenv; 1292 f_unsetenv = csh_unsetenv; 1293 } else { 1294 f_setenv = sh_setenv; 1295 f_unsetenv = sh_unsetenv; 1296 } 1297 if (k_flag) { 1298 const char *errstr = NULL; 1299 1300 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1301 if (pidstr == NULL) { 1302 fprintf(stderr, "%s not set, cannot kill agent\n", 1303 SSH_AGENTPID_ENV_NAME); 1304 exit(1); 1305 } 1306 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr); 1307 if (errstr) { 1308 fprintf(stderr, 1309 "%s=\"%s\", which is not a good PID: %s\n", 1310 SSH_AGENTPID_ENV_NAME, pidstr, errstr); 1311 exit(1); 1312 } 1313 if (kill(pid, SIGTERM) == -1) { 1314 perror("kill"); 1315 exit(1); 1316 } 1317 (*f_unsetenv)(SSH_AUTHSOCKET_ENV_NAME); 1318 (*f_unsetenv)(SSH_AGENTPID_ENV_NAME); 1319 printf("echo Agent pid %ld killed;\n", (long)pid); 1320 exit(0); 1321 } 1322 1323 /* 1324 * Minimum file descriptors: 1325 * stdio (3) + listener (1) + syslog (1 maybe) + connection (1) + 1326 * a few spare for libc / stack protectors / sanitisers, etc. 1327 */ 1328 #define SSH_AGENT_MIN_FDS (3+1+1+1+4) 1329 if (rlim.rlim_cur < SSH_AGENT_MIN_FDS) 1330 fatal("%s: file descriptor rlimit %lld too low (minimum %u)", 1331 __progname, (long long)rlim.rlim_cur, SSH_AGENT_MIN_FDS); 1332 maxfds = rlim.rlim_cur - SSH_AGENT_MIN_FDS; 1333 1334 parent_pid = getpid(); 1335 1336 if (agentsocket == NULL) { 1337 /* Create private directory for agent socket */ 1338 mktemp_proto(socket_dir, sizeof(socket_dir)); 1339 if (mkdtemp(socket_dir) == NULL) { 1340 perror("mkdtemp: private socket dir"); 1341 exit(1); 1342 } 1343 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1344 (long)parent_pid); 1345 } else { 1346 /* Try to use specified agent socket */ 1347 socket_dir[0] = '\0'; 1348 strlcpy(socket_name, agentsocket, sizeof socket_name); 1349 } 1350 1351 /* 1352 * Create socket early so it will exist before command gets run from 1353 * the parent. 1354 */ 1355 prev_mask = umask(0177); 1356 sock = unix_listener(socket_name, SSH_LISTEN_BACKLOG, 0); 1357 if (sock < 0) { 1358 /* XXX - unix_listener() calls error() not perror() */ 1359 *socket_name = '\0'; /* Don't unlink any existing file */ 1360 cleanup_exit(1); 1361 } 1362 umask(prev_mask); 1363 1364 /* 1365 * Fork, and have the parent execute the command, if any, or present 1366 * the socket data. The child continues as the authentication agent. 1367 */ 1368 if (D_flag || d_flag) { 1369 log_init(__progname, 1370 d_flag ? SYSLOG_LEVEL_DEBUG3 : SYSLOG_LEVEL_INFO, 1371 SYSLOG_FACILITY_AUTH, 1); 1372 if (c_flag) 1373 printf("setenv %s %s;\n", 1374 SSH_AUTHSOCKET_ENV_NAME, socket_name); 1375 else 1376 printf("%s=%s; export %s;\n", 1377 SSH_AUTHSOCKET_ENV_NAME, socket_name, 1378 SSH_AUTHSOCKET_ENV_NAME); 1379 printf("echo Agent pid %ld;\n", (long)parent_pid); 1380 fflush(stdout); 1381 goto skip; 1382 } 1383 pid = fork(); 1384 if (pid == -1) { 1385 perror("fork"); 1386 cleanup_exit(1); 1387 } 1388 if (pid != 0) { /* Parent - execute the given command. */ 1389 close(sock); 1390 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1391 if (ac == 0) { 1392 (*f_setenv)(SSH_AUTHSOCKET_ENV_NAME, socket_name); 1393 (*f_setenv)(SSH_AGENTPID_ENV_NAME, pidstrbuf); 1394 printf("echo Agent pid %ld;\n", (long)pid); 1395 exit(0); 1396 } 1397 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1398 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1399 perror("setenv"); 1400 exit(1); 1401 } 1402 execvp(av[0], av); 1403 perror(av[0]); 1404 exit(1); 1405 } 1406 /* child */ 1407 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1408 1409 if (setsid() == -1) { 1410 error("setsid: %s", strerror(errno)); 1411 cleanup_exit(1); 1412 } 1413 1414 (void)chdir("/"); 1415 1416 if (sock != STDERR_FILENO + 1) { 1417 if (dup2(sock, STDERR_FILENO + 1) == -1) { 1418 error("dup2: %s", strerror(errno)); 1419 cleanup_exit(1); 1420 } 1421 close(sock); 1422 sock = STDERR_FILENO + 1; 1423 } 1424 #if defined(F_CLOSEM) 1425 if (fcntl(sock + 1, F_CLOSEM, 0) == -1) { 1426 error("fcntl F_CLOSEM: %s", strerror(errno)); 1427 cleanup_exit(1); 1428 } 1429 #else 1430 { 1431 int nfiles; 1432 #if defined(_SC_OPEN_MAX) 1433 nfiles = sysconf(_SC_OPEN_MAX); 1434 #elif defined(RLIMIT_NOFILE) 1435 if (getrlimit(RLIMIT_CORE, &rlim) < 0) { 1436 error("getrlimit RLIMIT_NOFILE: %s", strerror(errno)); 1437 cleanup_exit(1); 1438 } 1439 nfiles = rlim.rlim_cur; 1440 #elif defined(OPEN_MAX) 1441 nfiles = OPEN_MAX; 1442 #elif defined(NOFILE) 1443 nfiles = NOFILE; 1444 #else 1445 nfiles = 1024; 1446 #endif 1447 for (fd = sock + 1; fd < nfiles; fd++) 1448 close(fd); 1449 } 1450 #endif 1451 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1452 if (dup2(fd, STDIN_FILENO) == -1 || 1453 dup2(fd, STDOUT_FILENO) == -1 || 1454 dup2(fd, STDERR_FILENO) == -1) { 1455 error("dup2: %s", strerror(errno)); 1456 cleanup_exit(1); 1457 } 1458 if (fd > STDERR_FILENO) 1459 close(fd); 1460 } 1461 1462 /* deny core dumps, since memory contains unencrypted private keys */ 1463 rlim.rlim_cur = rlim.rlim_max = 0; 1464 if (setrlimit(RLIMIT_CORE, &rlim) == -1) { 1465 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1466 cleanup_exit(1); 1467 } 1468 1469 skip: 1470 1471 cleanup_pid = getpid(); 1472 1473 #ifdef ENABLE_PKCS11 1474 pkcs11_init(0); 1475 #endif 1476 new_socket(AUTH_SOCKET, sock); 1477 if (ac > 0) 1478 parent_alive_interval = 10; 1479 idtab_init(); 1480 ssh_signal(SIGPIPE, SIG_IGN); 1481 ssh_signal(SIGINT, (d_flag | D_flag) ? cleanup_handler : SIG_IGN); 1482 ssh_signal(SIGHUP, cleanup_handler); 1483 ssh_signal(SIGTERM, cleanup_handler); 1484 1485 #ifdef __OpenBSD__ 1486 if (pledge("stdio rpath cpath unix id proc exec", NULL) == -1) 1487 fatal("%s: pledge: %s", __progname, strerror(errno)); 1488 #endif 1489 1490 while (1) { 1491 prepare_poll(&pfd, &npfd, &timeout, maxfds); 1492 result = poll(pfd, npfd, timeout); 1493 saved_errno = errno; 1494 if (parent_alive_interval != 0) 1495 check_parent_exists(); 1496 (void) reaper(); /* remove expired keys */ 1497 if (result == -1) { 1498 if (saved_errno == EINTR) 1499 continue; 1500 fatal("poll: %s", strerror(saved_errno)); 1501 } else if (result > 0) 1502 after_poll(pfd, npfd, maxfds); 1503 } 1504 /* NOTREACHED */ 1505 } 1506