1 /* $OpenBSD: ssh-agent.c,v 1.310 2025/02/18 08:02:48 djm 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/resource.h> 41 #include <sys/stat.h> 42 #include <sys/socket.h> 43 #include <sys/wait.h> 44 #ifdef HAVE_SYS_TIME_H 45 # include <sys/time.h> 46 #endif 47 #ifdef HAVE_SYS_UN_H 48 # include <sys/un.h> 49 #endif 50 #include "openbsd-compat/sys-queue.h" 51 52 #ifdef WITH_OPENSSL 53 #include <openssl/evp.h> 54 #include "openbsd-compat/openssl-compat.h" 55 #endif 56 57 #include <errno.h> 58 #include <fcntl.h> 59 #include <limits.h> 60 #ifdef HAVE_PATHS_H 61 # include <paths.h> 62 #endif 63 #ifdef HAVE_POLL_H 64 # include <poll.h> 65 #endif 66 #include <signal.h> 67 #include <stdarg.h> 68 #include <stdio.h> 69 #include <stdlib.h> 70 #include <time.h> 71 #include <string.h> 72 #include <unistd.h> 73 #ifdef HAVE_UTIL_H 74 # include <util.h> 75 #endif 76 77 #include "xmalloc.h" 78 #include "ssh.h" 79 #include "ssh2.h" 80 #include "sshbuf.h" 81 #include "sshkey.h" 82 #include "authfd.h" 83 #include "log.h" 84 #include "misc.h" 85 #include "digest.h" 86 #include "ssherr.h" 87 #include "match.h" 88 #include "msg.h" 89 #include "pathnames.h" 90 #include "ssh-pkcs11.h" 91 #include "sk-api.h" 92 #include "myproposal.h" 93 94 #ifndef DEFAULT_ALLOWED_PROVIDERS 95 # define DEFAULT_ALLOWED_PROVIDERS "/usr/lib*/*,/usr/local/lib*/*" 96 #endif 97 #ifndef DEFAULT_WEBSAFE_ALLOWLIST 98 # define DEFAULT_WEBSAFE_ALLOWLIST "ssh:*" 99 #endif 100 101 /* Maximum accepted message length */ 102 #define AGENT_MAX_LEN (256*1024) 103 /* Maximum bytes to read from client socket */ 104 #define AGENT_RBUF_LEN (4096) 105 /* Maximum number of recorded session IDs/hostkeys per connection */ 106 #define AGENT_MAX_SESSION_IDS 16 107 /* Maximum size of session ID */ 108 #define AGENT_MAX_SID_LEN 128 109 /* Maximum number of destination constraints to accept on a key */ 110 #define AGENT_MAX_DEST_CONSTRAINTS 1024 111 /* Maximum number of associated certificate constraints to accept on a key */ 112 #define AGENT_MAX_EXT_CERTS 1024 113 114 /* XXX store hostkey_sid in a refcounted tree */ 115 116 typedef enum { 117 AUTH_UNUSED = 0, 118 AUTH_SOCKET = 1, 119 AUTH_CONNECTION = 2, 120 } sock_type; 121 122 struct hostkey_sid { 123 struct sshkey *key; 124 struct sshbuf *sid; 125 int forwarded; 126 }; 127 128 typedef struct socket_entry { 129 int fd; 130 sock_type type; 131 struct sshbuf *input; 132 struct sshbuf *output; 133 struct sshbuf *request; 134 size_t nsession_ids; 135 struct hostkey_sid *session_ids; 136 int session_bind_attempted; 137 } SocketEntry; 138 139 u_int sockets_alloc = 0; 140 SocketEntry *sockets = NULL; 141 142 typedef struct identity { 143 TAILQ_ENTRY(identity) next; 144 struct sshkey *key; 145 char *comment; 146 char *provider; 147 time_t death; 148 u_int confirm; 149 char *sk_provider; 150 struct dest_constraint *dest_constraints; 151 size_t ndest_constraints; 152 } Identity; 153 154 struct idtable { 155 int nentries; 156 TAILQ_HEAD(idqueue, identity) idlist; 157 }; 158 159 /* private key table */ 160 struct idtable *idtab; 161 162 int max_fd = 0; 163 164 /* pid of shell == parent of agent */ 165 pid_t parent_pid = -1; 166 time_t parent_alive_interval = 0; 167 168 static sig_atomic_t signalled_exit; 169 static sig_atomic_t signalled_keydrop; 170 171 /* pid of process for which cleanup_socket is applicable */ 172 pid_t cleanup_pid = 0; 173 174 /* pathname and directory for AUTH_SOCKET */ 175 char socket_name[PATH_MAX]; 176 char socket_dir[PATH_MAX]; 177 178 /* Pattern-list of allowed PKCS#11/Security key paths */ 179 static char *allowed_providers; 180 181 /* 182 * Allows PKCS11 providers or SK keys that use non-internal providers to 183 * be added over a remote connection (identified by session-bind@openssh.com). 184 */ 185 static int remote_add_provider; 186 187 /* locking */ 188 #define LOCK_SIZE 32 189 #define LOCK_SALT_SIZE 16 190 #define LOCK_ROUNDS 1 191 int locked = 0; 192 u_char lock_pwhash[LOCK_SIZE]; 193 u_char lock_salt[LOCK_SALT_SIZE]; 194 195 extern char *__progname; 196 197 /* Default lifetime in seconds (0 == forever) */ 198 static int lifetime = 0; 199 200 static int fingerprint_hash = SSH_FP_HASH_DEFAULT; 201 202 /* Refuse signing of non-SSH messages for web-origin FIDO keys */ 203 static int restrict_websafe = 1; 204 static char *websafe_allowlist; 205 206 /* 207 * Client connection count; incremented in new_socket() and decremented in 208 * close_socket(). When it reaches 0, ssh-agent will exit. Since it is 209 * normally initialized to 1, it will never reach 0. However, if the -x 210 * option is specified, it is initialized to 0 in main(); in that case, 211 * ssh-agent will exit as soon as it has had at least one client but no 212 * longer has any. 213 */ 214 static int xcount = 1; 215 216 static void 217 close_socket(SocketEntry *e) 218 { 219 size_t i; 220 int last = 0; 221 222 if (e->type == AUTH_CONNECTION) { 223 debug("xcount %d -> %d", xcount, xcount - 1); 224 if (--xcount == 0) 225 last = 1; 226 } 227 close(e->fd); 228 sshbuf_free(e->input); 229 sshbuf_free(e->output); 230 sshbuf_free(e->request); 231 for (i = 0; i < e->nsession_ids; i++) { 232 sshkey_free(e->session_ids[i].key); 233 sshbuf_free(e->session_ids[i].sid); 234 } 235 free(e->session_ids); 236 memset(e, '\0', sizeof(*e)); 237 e->fd = -1; 238 e->type = AUTH_UNUSED; 239 if (last) 240 cleanup_exit(0); 241 } 242 243 static void 244 idtab_init(void) 245 { 246 idtab = xcalloc(1, sizeof(*idtab)); 247 TAILQ_INIT(&idtab->idlist); 248 idtab->nentries = 0; 249 } 250 251 static void 252 free_dest_constraint_hop(struct dest_constraint_hop *dch) 253 { 254 u_int i; 255 256 if (dch == NULL) 257 return; 258 free(dch->user); 259 free(dch->hostname); 260 for (i = 0; i < dch->nkeys; i++) 261 sshkey_free(dch->keys[i]); 262 free(dch->keys); 263 free(dch->key_is_ca); 264 } 265 266 static void 267 free_dest_constraints(struct dest_constraint *dcs, size_t ndcs) 268 { 269 size_t i; 270 271 for (i = 0; i < ndcs; i++) { 272 free_dest_constraint_hop(&dcs[i].from); 273 free_dest_constraint_hop(&dcs[i].to); 274 } 275 free(dcs); 276 } 277 278 #ifdef ENABLE_PKCS11 279 static void 280 dup_dest_constraint_hop(const struct dest_constraint_hop *dch, 281 struct dest_constraint_hop *out) 282 { 283 u_int i; 284 int r; 285 286 out->user = dch->user == NULL ? NULL : xstrdup(dch->user); 287 out->hostname = dch->hostname == NULL ? NULL : xstrdup(dch->hostname); 288 out->is_ca = dch->is_ca; 289 out->nkeys = dch->nkeys; 290 out->keys = out->nkeys == 0 ? NULL : 291 xcalloc(out->nkeys, sizeof(*out->keys)); 292 out->key_is_ca = out->nkeys == 0 ? NULL : 293 xcalloc(out->nkeys, sizeof(*out->key_is_ca)); 294 for (i = 0; i < dch->nkeys; i++) { 295 if (dch->keys[i] != NULL && 296 (r = sshkey_from_private(dch->keys[i], 297 &(out->keys[i]))) != 0) 298 fatal_fr(r, "copy key"); 299 out->key_is_ca[i] = dch->key_is_ca[i]; 300 } 301 } 302 303 static struct dest_constraint * 304 dup_dest_constraints(const struct dest_constraint *dcs, size_t ndcs) 305 { 306 size_t i; 307 struct dest_constraint *ret; 308 309 if (ndcs == 0) 310 return NULL; 311 ret = xcalloc(ndcs, sizeof(*ret)); 312 for (i = 0; i < ndcs; i++) { 313 dup_dest_constraint_hop(&dcs[i].from, &ret[i].from); 314 dup_dest_constraint_hop(&dcs[i].to, &ret[i].to); 315 } 316 return ret; 317 } 318 #endif /* ENABLE_PKCS11 */ 319 320 #ifdef DEBUG_CONSTRAINTS 321 static void 322 dump_dest_constraint_hop(const struct dest_constraint_hop *dch) 323 { 324 u_int i; 325 char *fp; 326 327 debug_f("user %s hostname %s is_ca %d nkeys %u", 328 dch->user == NULL ? "(null)" : dch->user, 329 dch->hostname == NULL ? "(null)" : dch->hostname, 330 dch->is_ca, dch->nkeys); 331 for (i = 0; i < dch->nkeys; i++) { 332 fp = NULL; 333 if (dch->keys[i] != NULL && 334 (fp = sshkey_fingerprint(dch->keys[i], 335 SSH_FP_HASH_DEFAULT, SSH_FP_DEFAULT)) == NULL) 336 fatal_f("fingerprint failed"); 337 debug_f("key %u/%u: %s%s%s key_is_ca %d", i, dch->nkeys, 338 dch->keys[i] == NULL ? "" : sshkey_ssh_name(dch->keys[i]), 339 dch->keys[i] == NULL ? "" : " ", 340 dch->keys[i] == NULL ? "none" : fp, 341 dch->key_is_ca[i]); 342 free(fp); 343 } 344 } 345 #endif /* DEBUG_CONSTRAINTS */ 346 347 static void 348 dump_dest_constraints(const char *context, 349 const struct dest_constraint *dcs, size_t ndcs) 350 { 351 #ifdef DEBUG_CONSTRAINTS 352 size_t i; 353 354 debug_f("%s: %zu constraints", context, ndcs); 355 for (i = 0; i < ndcs; i++) { 356 debug_f("constraint %zu / %zu: from: ", i, ndcs); 357 dump_dest_constraint_hop(&dcs[i].from); 358 debug_f("constraint %zu / %zu: to: ", i, ndcs); 359 dump_dest_constraint_hop(&dcs[i].to); 360 } 361 debug_f("done for %s", context); 362 #endif /* DEBUG_CONSTRAINTS */ 363 } 364 365 static void 366 free_identity(Identity *id) 367 { 368 sshkey_free(id->key); 369 free(id->provider); 370 free(id->comment); 371 free(id->sk_provider); 372 free_dest_constraints(id->dest_constraints, id->ndest_constraints); 373 free(id); 374 } 375 376 /* 377 * Match 'key' against the key/CA list in a destination constraint hop 378 * Returns 0 on success or -1 otherwise. 379 */ 380 static int 381 match_key_hop(const char *tag, const struct sshkey *key, 382 const struct dest_constraint_hop *dch) 383 { 384 const char *reason = NULL; 385 const char *hostname = dch->hostname ? dch->hostname : "(ORIGIN)"; 386 u_int i; 387 char *fp; 388 389 if (key == NULL) 390 return -1; 391 /* XXX logspam */ 392 if ((fp = sshkey_fingerprint(key, SSH_FP_HASH_DEFAULT, 393 SSH_FP_DEFAULT)) == NULL) 394 fatal_f("fingerprint failed"); 395 debug3_f("%s: entering hostname %s, requested key %s %s, %u keys avail", 396 tag, hostname, sshkey_type(key), fp, dch->nkeys); 397 free(fp); 398 for (i = 0; i < dch->nkeys; i++) { 399 if (dch->keys[i] == NULL) 400 return -1; 401 /* XXX logspam */ 402 if ((fp = sshkey_fingerprint(dch->keys[i], SSH_FP_HASH_DEFAULT, 403 SSH_FP_DEFAULT)) == NULL) 404 fatal_f("fingerprint failed"); 405 debug3_f("%s: key %u: %s%s %s", tag, i, 406 dch->key_is_ca[i] ? "CA " : "", 407 sshkey_type(dch->keys[i]), fp); 408 free(fp); 409 if (!sshkey_is_cert(key)) { 410 /* plain key */ 411 if (dch->key_is_ca[i] || 412 !sshkey_equal(key, dch->keys[i])) 413 continue; 414 return 0; 415 } 416 /* certificate */ 417 if (!dch->key_is_ca[i]) 418 continue; 419 if (key->cert == NULL || key->cert->signature_key == NULL) 420 return -1; /* shouldn't happen */ 421 if (!sshkey_equal(key->cert->signature_key, dch->keys[i])) 422 continue; 423 if (sshkey_cert_check_host(key, hostname, 1, 424 SSH_ALLOWED_CA_SIGALGS, &reason) != 0) { 425 debug_f("cert %s / hostname %s rejected: %s", 426 key->cert->key_id, hostname, reason); 427 continue; 428 } 429 return 0; 430 } 431 return -1; 432 } 433 434 /* Check destination constraints on an identity against the hostkey/user */ 435 static int 436 permitted_by_dest_constraints(const struct sshkey *fromkey, 437 const struct sshkey *tokey, Identity *id, const char *user, 438 const char **hostnamep) 439 { 440 size_t i; 441 struct dest_constraint *d; 442 443 if (hostnamep != NULL) 444 *hostnamep = NULL; 445 for (i = 0; i < id->ndest_constraints; i++) { 446 d = id->dest_constraints + i; 447 /* XXX remove logspam */ 448 debug2_f("constraint %zu %s%s%s (%u keys) > %s%s%s (%u keys)", 449 i, d->from.user ? d->from.user : "", 450 d->from.user ? "@" : "", 451 d->from.hostname ? d->from.hostname : "(ORIGIN)", 452 d->from.nkeys, 453 d->to.user ? d->to.user : "", d->to.user ? "@" : "", 454 d->to.hostname ? d->to.hostname : "(ANY)", d->to.nkeys); 455 456 /* Match 'from' key */ 457 if (fromkey == NULL) { 458 /* We are matching the first hop */ 459 if (d->from.hostname != NULL || d->from.nkeys != 0) 460 continue; 461 } else if (match_key_hop("from", fromkey, &d->from) != 0) 462 continue; 463 464 /* Match 'to' key */ 465 if (tokey != NULL && match_key_hop("to", tokey, &d->to) != 0) 466 continue; 467 468 /* Match user if specified */ 469 if (d->to.user != NULL && user != NULL && 470 !match_pattern(user, d->to.user)) 471 continue; 472 473 /* successfully matched this constraint */ 474 if (hostnamep != NULL) 475 *hostnamep = d->to.hostname; 476 debug2_f("allowed for hostname %s", 477 d->to.hostname == NULL ? "*" : d->to.hostname); 478 return 0; 479 } 480 /* no match */ 481 debug2_f("%s identity \"%s\" not permitted for this destination", 482 sshkey_type(id->key), id->comment); 483 return -1; 484 } 485 486 /* 487 * Check whether hostkeys on a SocketEntry and the optionally specified user 488 * are permitted by the destination constraints on the Identity. 489 * Returns 0 on success or -1 otherwise. 490 */ 491 static int 492 identity_permitted(Identity *id, SocketEntry *e, char *user, 493 const char **forward_hostnamep, const char **last_hostnamep) 494 { 495 size_t i; 496 const char **hp; 497 struct hostkey_sid *hks; 498 const struct sshkey *fromkey = NULL; 499 const char *test_user; 500 char *fp1, *fp2; 501 502 /* XXX remove logspam */ 503 debug3_f("entering: key %s comment \"%s\", %zu socket bindings, " 504 "%zu constraints", sshkey_type(id->key), id->comment, 505 e->nsession_ids, id->ndest_constraints); 506 if (id->ndest_constraints == 0) 507 return 0; /* unconstrained */ 508 if (e->session_bind_attempted && e->nsession_ids == 0) { 509 error_f("previous session bind failed on socket"); 510 return -1; 511 } 512 if (e->nsession_ids == 0) 513 return 0; /* local use */ 514 /* 515 * Walk through the hops recorded by session_id and try to find a 516 * constraint that satisfies each. 517 */ 518 for (i = 0; i < e->nsession_ids; i++) { 519 hks = e->session_ids + i; 520 if (hks->key == NULL) 521 fatal_f("internal error: no bound key"); 522 /* XXX remove logspam */ 523 fp1 = fp2 = NULL; 524 if (fromkey != NULL && 525 (fp1 = sshkey_fingerprint(fromkey, SSH_FP_HASH_DEFAULT, 526 SSH_FP_DEFAULT)) == NULL) 527 fatal_f("fingerprint failed"); 528 if ((fp2 = sshkey_fingerprint(hks->key, SSH_FP_HASH_DEFAULT, 529 SSH_FP_DEFAULT)) == NULL) 530 fatal_f("fingerprint failed"); 531 debug3_f("socketentry fd=%d, entry %zu %s, " 532 "from hostkey %s %s to user %s hostkey %s %s", 533 e->fd, i, hks->forwarded ? "FORWARD" : "AUTH", 534 fromkey ? sshkey_type(fromkey) : "(ORIGIN)", 535 fromkey ? fp1 : "", user ? user : "(ANY)", 536 sshkey_type(hks->key), fp2); 537 free(fp1); 538 free(fp2); 539 /* 540 * Record the hostnames for the initial forwarding and 541 * the final destination. 542 */ 543 hp = NULL; 544 if (i == e->nsession_ids - 1) 545 hp = last_hostnamep; 546 else if (i == 0) 547 hp = forward_hostnamep; 548 /* Special handling for final recorded binding */ 549 test_user = NULL; 550 if (i == e->nsession_ids - 1) { 551 /* Can only check user at final hop */ 552 test_user = user; 553 /* 554 * user is only presented for signature requests. 555 * If this is the case, make sure last binding is not 556 * for a forwarding. 557 */ 558 if (hks->forwarded && user != NULL) { 559 error_f("tried to sign on forwarding hop"); 560 return -1; 561 } 562 } else if (!hks->forwarded) { 563 error_f("tried to forward though signing bind"); 564 return -1; 565 } 566 if (permitted_by_dest_constraints(fromkey, hks->key, id, 567 test_user, hp) != 0) 568 return -1; 569 fromkey = hks->key; 570 } 571 /* 572 * Another special case: if the last bound session ID was for a 573 * forwarding, and this function is not being called to check a sign 574 * request (i.e. no 'user' supplied), then only permit the key if 575 * there is a permission that would allow it to be used at another 576 * destination. This hides keys that are allowed to be used to 577 * authenticate *to* a host but not permitted for *use* beyond it. 578 */ 579 hks = &e->session_ids[e->nsession_ids - 1]; 580 if (hks->forwarded && user == NULL && 581 permitted_by_dest_constraints(hks->key, NULL, id, 582 NULL, NULL) != 0) { 583 debug3_f("key permitted at host but not after"); 584 return -1; 585 } 586 587 /* success */ 588 return 0; 589 } 590 591 static int 592 socket_is_remote(SocketEntry *e) 593 { 594 return e->session_bind_attempted || (e->nsession_ids != 0); 595 } 596 597 /* return matching private key for given public key */ 598 static Identity * 599 lookup_identity(struct sshkey *key) 600 { 601 Identity *id; 602 603 TAILQ_FOREACH(id, &idtab->idlist, next) { 604 if (sshkey_equal(key, id->key)) 605 return (id); 606 } 607 return (NULL); 608 } 609 610 /* Check confirmation of keysign request */ 611 static int 612 confirm_key(Identity *id, const char *extra) 613 { 614 char *p; 615 int ret = -1; 616 617 p = sshkey_fingerprint(id->key, fingerprint_hash, SSH_FP_DEFAULT); 618 if (p != NULL && 619 ask_permission("Allow use of key %s?\nKey fingerprint %s.%s%s", 620 id->comment, p, 621 extra == NULL ? "" : "\n", extra == NULL ? "" : extra)) 622 ret = 0; 623 free(p); 624 625 return (ret); 626 } 627 628 static void 629 send_status(SocketEntry *e, int success) 630 { 631 int r; 632 633 if ((r = sshbuf_put_u32(e->output, 1)) != 0 || 634 (r = sshbuf_put_u8(e->output, success ? 635 SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0) 636 fatal_fr(r, "compose"); 637 } 638 639 /* send list of supported public keys to 'client' */ 640 static void 641 process_request_identities(SocketEntry *e) 642 { 643 Identity *id; 644 struct sshbuf *msg, *keys; 645 int r; 646 u_int i = 0, nentries = 0; 647 char *fp; 648 649 debug2_f("entering"); 650 651 if ((msg = sshbuf_new()) == NULL || (keys = sshbuf_new()) == NULL) 652 fatal_f("sshbuf_new failed"); 653 TAILQ_FOREACH(id, &idtab->idlist, next) { 654 if ((fp = sshkey_fingerprint(id->key, SSH_FP_HASH_DEFAULT, 655 SSH_FP_DEFAULT)) == NULL) 656 fatal_f("fingerprint failed"); 657 debug_f("key %u / %u: %s %s", i++, idtab->nentries, 658 sshkey_ssh_name(id->key), fp); 659 dump_dest_constraints(__func__, 660 id->dest_constraints, id->ndest_constraints); 661 free(fp); 662 /* identity not visible, don't include in response */ 663 if (identity_permitted(id, e, NULL, NULL, NULL) != 0) 664 continue; 665 if ((r = sshkey_puts_opts(id->key, keys, 666 SSHKEY_SERIALIZE_INFO)) != 0 || 667 (r = sshbuf_put_cstring(keys, id->comment)) != 0) { 668 error_fr(r, "compose key/comment"); 669 continue; 670 } 671 nentries++; 672 } 673 debug2_f("replying with %u allowed of %u available keys", 674 nentries, idtab->nentries); 675 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 676 (r = sshbuf_put_u32(msg, nentries)) != 0 || 677 (r = sshbuf_putb(msg, keys)) != 0) 678 fatal_fr(r, "compose"); 679 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 680 fatal_fr(r, "enqueue"); 681 sshbuf_free(msg); 682 sshbuf_free(keys); 683 } 684 685 686 static char * 687 agent_decode_alg(struct sshkey *key, u_int flags) 688 { 689 if (key->type == KEY_RSA) { 690 if (flags & SSH_AGENT_RSA_SHA2_256) 691 return "rsa-sha2-256"; 692 else if (flags & SSH_AGENT_RSA_SHA2_512) 693 return "rsa-sha2-512"; 694 } else if (key->type == KEY_RSA_CERT) { 695 if (flags & SSH_AGENT_RSA_SHA2_256) 696 return "rsa-sha2-256-cert-v01@openssh.com"; 697 else if (flags & SSH_AGENT_RSA_SHA2_512) 698 return "rsa-sha2-512-cert-v01@openssh.com"; 699 } 700 return NULL; 701 } 702 703 /* 704 * Attempt to parse the contents of a buffer as a SSH publickey userauth 705 * request, checking its contents for consistency and matching the embedded 706 * key against the one that is being used for signing. 707 * Note: does not modify msg buffer. 708 * Optionally extract the username, session ID and/or hostkey from the request. 709 */ 710 static int 711 parse_userauth_request(struct sshbuf *msg, const struct sshkey *expected_key, 712 char **userp, struct sshbuf **sess_idp, struct sshkey **hostkeyp) 713 { 714 struct sshbuf *b = NULL, *sess_id = NULL; 715 char *user = NULL, *service = NULL, *method = NULL, *pkalg = NULL; 716 int r; 717 u_char t, sig_follows; 718 struct sshkey *mkey = NULL, *hostkey = NULL; 719 720 if (userp != NULL) 721 *userp = NULL; 722 if (sess_idp != NULL) 723 *sess_idp = NULL; 724 if (hostkeyp != NULL) 725 *hostkeyp = NULL; 726 if ((b = sshbuf_fromb(msg)) == NULL) 727 fatal_f("sshbuf_fromb"); 728 729 /* SSH userauth request */ 730 if ((r = sshbuf_froms(b, &sess_id)) != 0) 731 goto out; 732 if (sshbuf_len(sess_id) == 0) { 733 r = SSH_ERR_INVALID_FORMAT; 734 goto out; 735 } 736 if ((r = sshbuf_get_u8(b, &t)) != 0 || /* SSH2_MSG_USERAUTH_REQUEST */ 737 (r = sshbuf_get_cstring(b, &user, NULL)) != 0 || /* server user */ 738 (r = sshbuf_get_cstring(b, &service, NULL)) != 0 || /* service */ 739 (r = sshbuf_get_cstring(b, &method, NULL)) != 0 || /* method */ 740 (r = sshbuf_get_u8(b, &sig_follows)) != 0 || /* sig-follows */ 741 (r = sshbuf_get_cstring(b, &pkalg, NULL)) != 0 || /* alg */ 742 (r = sshkey_froms(b, &mkey)) != 0) /* key */ 743 goto out; 744 if (t != SSH2_MSG_USERAUTH_REQUEST || 745 sig_follows != 1 || 746 strcmp(service, "ssh-connection") != 0 || 747 !sshkey_equal(expected_key, mkey) || 748 sshkey_type_from_name(pkalg) != expected_key->type) { 749 r = SSH_ERR_INVALID_FORMAT; 750 goto out; 751 } 752 if (strcmp(method, "publickey-hostbound-v00@openssh.com") == 0) { 753 if ((r = sshkey_froms(b, &hostkey)) != 0) 754 goto out; 755 } else if (strcmp(method, "publickey") != 0) { 756 r = SSH_ERR_INVALID_FORMAT; 757 goto out; 758 } 759 if (sshbuf_len(b) != 0) { 760 r = SSH_ERR_INVALID_FORMAT; 761 goto out; 762 } 763 /* success */ 764 r = 0; 765 debug3_f("well formed userauth"); 766 if (userp != NULL) { 767 *userp = user; 768 user = NULL; 769 } 770 if (sess_idp != NULL) { 771 *sess_idp = sess_id; 772 sess_id = NULL; 773 } 774 if (hostkeyp != NULL) { 775 *hostkeyp = hostkey; 776 hostkey = NULL; 777 } 778 out: 779 sshbuf_free(b); 780 sshbuf_free(sess_id); 781 free(user); 782 free(service); 783 free(method); 784 free(pkalg); 785 sshkey_free(mkey); 786 sshkey_free(hostkey); 787 return r; 788 } 789 790 /* 791 * Attempt to parse the contents of a buffer as a SSHSIG signature request. 792 * Note: does not modify buffer. 793 */ 794 static int 795 parse_sshsig_request(struct sshbuf *msg) 796 { 797 int r; 798 struct sshbuf *b; 799 800 if ((b = sshbuf_fromb(msg)) == NULL) 801 fatal_f("sshbuf_fromb"); 802 803 if ((r = sshbuf_cmp(b, 0, "SSHSIG", 6)) != 0 || 804 (r = sshbuf_consume(b, 6)) != 0 || 805 (r = sshbuf_get_cstring(b, NULL, NULL)) != 0 || /* namespace */ 806 (r = sshbuf_get_string_direct(b, NULL, NULL)) != 0 || /* reserved */ 807 (r = sshbuf_get_cstring(b, NULL, NULL)) != 0 || /* hashalg */ 808 (r = sshbuf_get_string_direct(b, NULL, NULL)) != 0) /* H(msg) */ 809 goto out; 810 if (sshbuf_len(b) != 0) { 811 r = SSH_ERR_INVALID_FORMAT; 812 goto out; 813 } 814 /* success */ 815 r = 0; 816 out: 817 sshbuf_free(b); 818 return r; 819 } 820 821 /* 822 * This function inspects a message to be signed by a FIDO key that has a 823 * web-like application string (i.e. one that does not begin with "ssh:". 824 * It checks that the message is one of those expected for SSH operations 825 * (pubkey userauth, sshsig, CA key signing) to exclude signing challenges 826 * for the web. 827 */ 828 static int 829 check_websafe_message_contents(struct sshkey *key, struct sshbuf *data) 830 { 831 if (parse_userauth_request(data, key, NULL, NULL, NULL) == 0) { 832 debug_f("signed data matches public key userauth request"); 833 return 1; 834 } 835 if (parse_sshsig_request(data) == 0) { 836 debug_f("signed data matches SSHSIG signature request"); 837 return 1; 838 } 839 840 /* XXX check CA signature operation */ 841 842 error("web-origin key attempting to sign non-SSH message"); 843 return 0; 844 } 845 846 static int 847 buf_equal(const struct sshbuf *a, const struct sshbuf *b) 848 { 849 if (sshbuf_ptr(a) == NULL || sshbuf_ptr(b) == NULL) 850 return SSH_ERR_INVALID_ARGUMENT; 851 if (sshbuf_len(a) != sshbuf_len(b)) 852 return SSH_ERR_INVALID_FORMAT; 853 if (timingsafe_bcmp(sshbuf_ptr(a), sshbuf_ptr(b), sshbuf_len(a)) != 0) 854 return SSH_ERR_INVALID_FORMAT; 855 return 0; 856 } 857 858 /* ssh2 only */ 859 static void 860 process_sign_request2(SocketEntry *e) 861 { 862 u_char *signature = NULL; 863 size_t slen = 0; 864 u_int compat = 0, flags; 865 int r, ok = -1, retried = 0; 866 char *fp = NULL, *pin = NULL, *prompt = NULL; 867 char *user = NULL, *sig_dest = NULL; 868 const char *fwd_host = NULL, *dest_host = NULL; 869 struct sshbuf *msg = NULL, *data = NULL, *sid = NULL; 870 struct sshkey *key = NULL, *hostkey = NULL; 871 struct identity *id; 872 struct notifier_ctx *notifier = NULL; 873 874 debug_f("entering"); 875 876 if ((msg = sshbuf_new()) == NULL || (data = sshbuf_new()) == NULL) 877 fatal_f("sshbuf_new failed"); 878 if ((r = sshkey_froms(e->request, &key)) != 0 || 879 (r = sshbuf_get_stringb(e->request, data)) != 0 || 880 (r = sshbuf_get_u32(e->request, &flags)) != 0) { 881 error_fr(r, "parse"); 882 goto send; 883 } 884 885 if ((id = lookup_identity(key)) == NULL) { 886 verbose_f("%s key not found", sshkey_type(key)); 887 goto send; 888 } 889 if ((fp = sshkey_fingerprint(key, SSH_FP_HASH_DEFAULT, 890 SSH_FP_DEFAULT)) == NULL) 891 fatal_f("fingerprint failed"); 892 893 if (id->ndest_constraints != 0) { 894 if (e->nsession_ids == 0) { 895 logit_f("refusing use of destination-constrained key " 896 "to sign on unbound connection"); 897 goto send; 898 } 899 if (parse_userauth_request(data, key, &user, &sid, 900 &hostkey) != 0) { 901 logit_f("refusing use of destination-constrained key " 902 "to sign an unidentified signature"); 903 goto send; 904 } 905 /* XXX logspam */ 906 debug_f("user=%s", user); 907 if (identity_permitted(id, e, user, &fwd_host, &dest_host) != 0) 908 goto send; 909 /* XXX display fwd_host/dest_host in askpass UI */ 910 /* 911 * Ensure that the session ID is the most recent one 912 * registered on the socket - it should have been bound by 913 * ssh immediately before userauth. 914 */ 915 if (buf_equal(sid, 916 e->session_ids[e->nsession_ids - 1].sid) != 0) { 917 error_f("unexpected session ID (%zu listed) on " 918 "signature request for target user %s with " 919 "key %s %s", e->nsession_ids, user, 920 sshkey_type(id->key), fp); 921 goto send; 922 } 923 /* 924 * Ensure that the hostkey embedded in the signature matches 925 * the one most recently bound to the socket. An exception is 926 * made for the initial forwarding hop. 927 */ 928 if (e->nsession_ids > 1 && hostkey == NULL) { 929 error_f("refusing use of destination-constrained key: " 930 "no hostkey recorded in signature for forwarded " 931 "connection"); 932 goto send; 933 } 934 if (hostkey != NULL && !sshkey_equal(hostkey, 935 e->session_ids[e->nsession_ids - 1].key)) { 936 error_f("refusing use of destination-constrained key: " 937 "mismatch between hostkey in request and most " 938 "recently bound session"); 939 goto send; 940 } 941 xasprintf(&sig_dest, "public key authentication request for " 942 "user \"%s\" to listed host", user); 943 } 944 if (id->confirm && confirm_key(id, sig_dest) != 0) { 945 verbose_f("user refused key"); 946 goto send; 947 } 948 if (sshkey_is_sk(id->key)) { 949 if (restrict_websafe && 950 match_pattern_list(id->key->sk_application, 951 websafe_allowlist, 0) != 1 && 952 !check_websafe_message_contents(key, data)) { 953 /* error already logged */ 954 goto send; 955 } 956 if (id->key->sk_flags & SSH_SK_USER_PRESENCE_REQD) { 957 notifier = notify_start(0, 958 "Confirm user presence for key %s %s%s%s", 959 sshkey_type(id->key), fp, 960 sig_dest == NULL ? "" : "\n", 961 sig_dest == NULL ? "" : sig_dest); 962 } 963 } 964 retry_pin: 965 if ((r = sshkey_sign(id->key, &signature, &slen, 966 sshbuf_ptr(data), sshbuf_len(data), agent_decode_alg(key, flags), 967 id->sk_provider, pin, compat)) != 0) { 968 debug_fr(r, "sshkey_sign"); 969 if (pin == NULL && !retried && sshkey_is_sk(id->key) && 970 r == SSH_ERR_KEY_WRONG_PASSPHRASE) { 971 notify_complete(notifier, NULL); 972 notifier = NULL; 973 /* XXX include sig_dest */ 974 xasprintf(&prompt, "Enter PIN%sfor %s key %s: ", 975 (id->key->sk_flags & SSH_SK_USER_PRESENCE_REQD) ? 976 " and confirm user presence " : " ", 977 sshkey_type(id->key), fp); 978 pin = read_passphrase(prompt, RP_USE_ASKPASS); 979 retried = 1; 980 goto retry_pin; 981 } 982 error_fr(r, "sshkey_sign"); 983 goto send; 984 } 985 /* Success */ 986 ok = 0; 987 debug_f("good signature"); 988 send: 989 notify_complete(notifier, "User presence confirmed"); 990 991 if (ok == 0) { 992 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 || 993 (r = sshbuf_put_string(msg, signature, slen)) != 0) 994 fatal_fr(r, "compose"); 995 } else if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0) 996 fatal_fr(r, "compose failure"); 997 998 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 999 fatal_fr(r, "enqueue"); 1000 1001 sshbuf_free(sid); 1002 sshbuf_free(data); 1003 sshbuf_free(msg); 1004 sshkey_free(key); 1005 sshkey_free(hostkey); 1006 free(fp); 1007 free(signature); 1008 free(sig_dest); 1009 free(user); 1010 free(prompt); 1011 if (pin != NULL) 1012 freezero(pin, strlen(pin)); 1013 } 1014 1015 /* shared */ 1016 static void 1017 process_remove_identity(SocketEntry *e) 1018 { 1019 int r, success = 0; 1020 struct sshkey *key = NULL; 1021 Identity *id; 1022 1023 debug2_f("entering"); 1024 if ((r = sshkey_froms(e->request, &key)) != 0) { 1025 error_fr(r, "parse key"); 1026 goto done; 1027 } 1028 if ((id = lookup_identity(key)) == NULL) { 1029 debug_f("key not found"); 1030 goto done; 1031 } 1032 /* identity not visible, cannot be removed */ 1033 if (identity_permitted(id, e, NULL, NULL, NULL) != 0) 1034 goto done; /* error already logged */ 1035 /* We have this key, free it. */ 1036 if (idtab->nentries < 1) 1037 fatal_f("internal error: nentries %d", idtab->nentries); 1038 TAILQ_REMOVE(&idtab->idlist, id, next); 1039 free_identity(id); 1040 idtab->nentries--; 1041 success = 1; 1042 done: 1043 sshkey_free(key); 1044 send_status(e, success); 1045 } 1046 1047 static void 1048 remove_all_identities(void) 1049 { 1050 Identity *id; 1051 1052 debug2_f("entering"); 1053 /* Loop over all identities and clear the keys. */ 1054 for (id = TAILQ_FIRST(&idtab->idlist); id; 1055 id = TAILQ_FIRST(&idtab->idlist)) { 1056 TAILQ_REMOVE(&idtab->idlist, id, next); 1057 free_identity(id); 1058 } 1059 1060 /* Mark that there are no identities. */ 1061 idtab->nentries = 0; 1062 } 1063 1064 static void 1065 process_remove_all_identities(SocketEntry *e) 1066 { 1067 remove_all_identities(); 1068 1069 /* Send success. */ 1070 send_status(e, 1); 1071 } 1072 1073 /* removes expired keys and returns number of seconds until the next expiry */ 1074 static time_t 1075 reaper(void) 1076 { 1077 time_t deadline = 0, now = monotime(); 1078 Identity *id, *nxt; 1079 1080 for (id = TAILQ_FIRST(&idtab->idlist); id; id = nxt) { 1081 nxt = TAILQ_NEXT(id, next); 1082 if (id->death == 0) 1083 continue; 1084 if (now >= id->death) { 1085 debug("expiring key '%s'", id->comment); 1086 TAILQ_REMOVE(&idtab->idlist, id, next); 1087 free_identity(id); 1088 idtab->nentries--; 1089 } else 1090 deadline = (deadline == 0) ? id->death : 1091 MINIMUM(deadline, id->death); 1092 } 1093 if (deadline == 0 || deadline <= now) 1094 return 0; 1095 else 1096 return (deadline - now); 1097 } 1098 1099 static int 1100 parse_dest_constraint_hop(struct sshbuf *b, struct dest_constraint_hop *dch) 1101 { 1102 u_char key_is_ca; 1103 size_t elen = 0; 1104 int r; 1105 struct sshkey *k = NULL; 1106 char *fp; 1107 1108 memset(dch, '\0', sizeof(*dch)); 1109 if ((r = sshbuf_get_cstring(b, &dch->user, NULL)) != 0 || 1110 (r = sshbuf_get_cstring(b, &dch->hostname, NULL)) != 0 || 1111 (r = sshbuf_get_string_direct(b, NULL, &elen)) != 0) { 1112 error_fr(r, "parse"); 1113 goto out; 1114 } 1115 if (elen != 0) { 1116 error_f("unsupported extensions (len %zu)", elen); 1117 r = SSH_ERR_FEATURE_UNSUPPORTED; 1118 goto out; 1119 } 1120 if (*dch->hostname == '\0') { 1121 free(dch->hostname); 1122 dch->hostname = NULL; 1123 } 1124 if (*dch->user == '\0') { 1125 free(dch->user); 1126 dch->user = NULL; 1127 } 1128 while (sshbuf_len(b) != 0) { 1129 dch->keys = xrecallocarray(dch->keys, dch->nkeys, 1130 dch->nkeys + 1, sizeof(*dch->keys)); 1131 dch->key_is_ca = xrecallocarray(dch->key_is_ca, dch->nkeys, 1132 dch->nkeys + 1, sizeof(*dch->key_is_ca)); 1133 if ((r = sshkey_froms(b, &k)) != 0 || 1134 (r = sshbuf_get_u8(b, &key_is_ca)) != 0) 1135 goto out; 1136 if ((fp = sshkey_fingerprint(k, SSH_FP_HASH_DEFAULT, 1137 SSH_FP_DEFAULT)) == NULL) 1138 fatal_f("fingerprint failed"); 1139 debug3_f("%s%s%s: adding %skey %s %s", 1140 dch->user == NULL ? "" : dch->user, 1141 dch->user == NULL ? "" : "@", 1142 dch->hostname, key_is_ca ? "CA " : "", sshkey_type(k), fp); 1143 free(fp); 1144 dch->keys[dch->nkeys] = k; 1145 dch->key_is_ca[dch->nkeys] = key_is_ca != 0; 1146 dch->nkeys++; 1147 k = NULL; /* transferred */ 1148 } 1149 /* success */ 1150 r = 0; 1151 out: 1152 sshkey_free(k); 1153 return r; 1154 } 1155 1156 static int 1157 parse_dest_constraint(struct sshbuf *m, struct dest_constraint *dc) 1158 { 1159 struct sshbuf *b = NULL, *frombuf = NULL, *tobuf = NULL; 1160 int r; 1161 size_t elen = 0; 1162 1163 debug3_f("entering"); 1164 1165 memset(dc, '\0', sizeof(*dc)); 1166 if ((r = sshbuf_froms(m, &b)) != 0 || 1167 (r = sshbuf_froms(b, &frombuf)) != 0 || 1168 (r = sshbuf_froms(b, &tobuf)) != 0 || 1169 (r = sshbuf_get_string_direct(b, NULL, &elen)) != 0) { 1170 error_fr(r, "parse"); 1171 goto out; 1172 } 1173 if ((r = parse_dest_constraint_hop(frombuf, &dc->from)) != 0 || 1174 (r = parse_dest_constraint_hop(tobuf, &dc->to)) != 0) 1175 goto out; /* already logged */ 1176 if (elen != 0) { 1177 error_f("unsupported extensions (len %zu)", elen); 1178 r = SSH_ERR_FEATURE_UNSUPPORTED; 1179 goto out; 1180 } 1181 debug2_f("parsed %s (%u keys) > %s%s%s (%u keys)", 1182 dc->from.hostname ? dc->from.hostname : "(ORIGIN)", dc->from.nkeys, 1183 dc->to.user ? dc->to.user : "", dc->to.user ? "@" : "", 1184 dc->to.hostname ? dc->to.hostname : "(ANY)", dc->to.nkeys); 1185 /* check consistency */ 1186 if ((dc->from.hostname == NULL) != (dc->from.nkeys == 0) || 1187 dc->from.user != NULL) { 1188 error_f("inconsistent \"from\" specification"); 1189 r = SSH_ERR_INVALID_FORMAT; 1190 goto out; 1191 } 1192 if (dc->to.hostname == NULL || dc->to.nkeys == 0) { 1193 error_f("incomplete \"to\" specification"); 1194 r = SSH_ERR_INVALID_FORMAT; 1195 goto out; 1196 } 1197 /* success */ 1198 r = 0; 1199 out: 1200 sshbuf_free(b); 1201 sshbuf_free(frombuf); 1202 sshbuf_free(tobuf); 1203 return r; 1204 } 1205 1206 static int 1207 parse_key_constraint_extension(struct sshbuf *m, char **sk_providerp, 1208 struct dest_constraint **dcsp, size_t *ndcsp, int *cert_onlyp, 1209 struct sshkey ***certs, size_t *ncerts) 1210 { 1211 char *ext_name = NULL; 1212 int r; 1213 struct sshbuf *b = NULL; 1214 u_char v; 1215 struct sshkey *k; 1216 1217 if ((r = sshbuf_get_cstring(m, &ext_name, NULL)) != 0) { 1218 error_fr(r, "parse constraint extension"); 1219 goto out; 1220 } 1221 debug_f("constraint ext %s", ext_name); 1222 if (strcmp(ext_name, "sk-provider@openssh.com") == 0) { 1223 if (sk_providerp == NULL) { 1224 error_f("%s not valid here", ext_name); 1225 r = SSH_ERR_INVALID_FORMAT; 1226 goto out; 1227 } 1228 if (*sk_providerp != NULL) { 1229 error_f("%s already set", ext_name); 1230 r = SSH_ERR_INVALID_FORMAT; 1231 goto out; 1232 } 1233 if ((r = sshbuf_get_cstring(m, sk_providerp, NULL)) != 0) { 1234 error_fr(r, "parse %s", ext_name); 1235 goto out; 1236 } 1237 } else if (strcmp(ext_name, 1238 "restrict-destination-v00@openssh.com") == 0) { 1239 if (*dcsp != NULL) { 1240 error_f("%s already set", ext_name); 1241 r = SSH_ERR_INVALID_FORMAT; 1242 goto out; 1243 } 1244 if ((r = sshbuf_froms(m, &b)) != 0) { 1245 error_fr(r, "parse %s outer", ext_name); 1246 goto out; 1247 } 1248 while (sshbuf_len(b) != 0) { 1249 if (*ndcsp >= AGENT_MAX_DEST_CONSTRAINTS) { 1250 error_f("too many %s constraints", ext_name); 1251 r = SSH_ERR_INVALID_FORMAT; 1252 goto out; 1253 } 1254 *dcsp = xrecallocarray(*dcsp, *ndcsp, *ndcsp + 1, 1255 sizeof(**dcsp)); 1256 if ((r = parse_dest_constraint(b, 1257 *dcsp + (*ndcsp)++)) != 0) 1258 goto out; /* error already logged */ 1259 } 1260 } else if (strcmp(ext_name, 1261 "associated-certs-v00@openssh.com") == 0) { 1262 if (certs == NULL || ncerts == NULL || cert_onlyp == NULL) { 1263 error_f("%s not valid here", ext_name); 1264 r = SSH_ERR_INVALID_FORMAT; 1265 goto out; 1266 } 1267 if (*certs != NULL) { 1268 error_f("%s already set", ext_name); 1269 r = SSH_ERR_INVALID_FORMAT; 1270 goto out; 1271 } 1272 if ((r = sshbuf_get_u8(m, &v)) != 0 || 1273 (r = sshbuf_froms(m, &b)) != 0) { 1274 error_fr(r, "parse %s", ext_name); 1275 goto out; 1276 } 1277 *cert_onlyp = v != 0; 1278 while (sshbuf_len(b) != 0) { 1279 if (*ncerts >= AGENT_MAX_EXT_CERTS) { 1280 error_f("too many %s constraints", ext_name); 1281 r = SSH_ERR_INVALID_FORMAT; 1282 goto out; 1283 } 1284 *certs = xrecallocarray(*certs, *ncerts, *ncerts + 1, 1285 sizeof(**certs)); 1286 if ((r = sshkey_froms(b, &k)) != 0) { 1287 error_fr(r, "parse key"); 1288 goto out; 1289 } 1290 (*certs)[(*ncerts)++] = k; 1291 } 1292 } else { 1293 error_f("unsupported constraint \"%s\"", ext_name); 1294 r = SSH_ERR_FEATURE_UNSUPPORTED; 1295 goto out; 1296 } 1297 /* success */ 1298 r = 0; 1299 out: 1300 free(ext_name); 1301 sshbuf_free(b); 1302 return r; 1303 } 1304 1305 static int 1306 parse_key_constraints(struct sshbuf *m, struct sshkey *k, time_t *deathp, 1307 u_int *secondsp, int *confirmp, char **sk_providerp, 1308 struct dest_constraint **dcsp, size_t *ndcsp, 1309 int *cert_onlyp, size_t *ncerts, struct sshkey ***certs) 1310 { 1311 u_char ctype; 1312 int r; 1313 u_int seconds, maxsign = 0; 1314 1315 while (sshbuf_len(m)) { 1316 if ((r = sshbuf_get_u8(m, &ctype)) != 0) { 1317 error_fr(r, "parse constraint type"); 1318 goto out; 1319 } 1320 switch (ctype) { 1321 case SSH_AGENT_CONSTRAIN_LIFETIME: 1322 if (*deathp != 0) { 1323 error_f("lifetime already set"); 1324 r = SSH_ERR_INVALID_FORMAT; 1325 goto out; 1326 } 1327 if ((r = sshbuf_get_u32(m, &seconds)) != 0) { 1328 error_fr(r, "parse lifetime constraint"); 1329 goto out; 1330 } 1331 *deathp = monotime() + seconds; 1332 *secondsp = seconds; 1333 break; 1334 case SSH_AGENT_CONSTRAIN_CONFIRM: 1335 if (*confirmp != 0) { 1336 error_f("confirm already set"); 1337 r = SSH_ERR_INVALID_FORMAT; 1338 goto out; 1339 } 1340 *confirmp = 1; 1341 break; 1342 case SSH_AGENT_CONSTRAIN_MAXSIGN: 1343 if (k == NULL) { 1344 error_f("maxsign not valid here"); 1345 r = SSH_ERR_INVALID_FORMAT; 1346 goto out; 1347 } 1348 if (maxsign != 0) { 1349 error_f("maxsign already set"); 1350 r = SSH_ERR_INVALID_FORMAT; 1351 goto out; 1352 } 1353 if ((r = sshbuf_get_u32(m, &maxsign)) != 0) { 1354 error_fr(r, "parse maxsign constraint"); 1355 goto out; 1356 } 1357 if ((r = sshkey_enable_maxsign(k, maxsign)) != 0) { 1358 error_fr(r, "enable maxsign"); 1359 goto out; 1360 } 1361 break; 1362 case SSH_AGENT_CONSTRAIN_EXTENSION: 1363 if ((r = parse_key_constraint_extension(m, 1364 sk_providerp, dcsp, ndcsp, 1365 cert_onlyp, certs, ncerts)) != 0) 1366 goto out; /* error already logged */ 1367 break; 1368 default: 1369 error_f("Unknown constraint %d", ctype); 1370 r = SSH_ERR_FEATURE_UNSUPPORTED; 1371 goto out; 1372 } 1373 } 1374 /* success */ 1375 r = 0; 1376 out: 1377 return r; 1378 } 1379 1380 static void 1381 process_add_identity(SocketEntry *e) 1382 { 1383 Identity *id; 1384 int success = 0, confirm = 0; 1385 char *fp, *comment = NULL, *sk_provider = NULL; 1386 char canonical_provider[PATH_MAX]; 1387 time_t death = 0; 1388 u_int seconds = 0; 1389 struct dest_constraint *dest_constraints = NULL; 1390 size_t ndest_constraints = 0; 1391 struct sshkey *k = NULL; 1392 int r = SSH_ERR_INTERNAL_ERROR; 1393 1394 debug2_f("entering"); 1395 if ((r = sshkey_private_deserialize(e->request, &k)) != 0 || 1396 k == NULL || 1397 (r = sshbuf_get_cstring(e->request, &comment, NULL)) != 0) { 1398 error_fr(r, "parse"); 1399 goto out; 1400 } 1401 if (parse_key_constraints(e->request, k, &death, &seconds, &confirm, 1402 &sk_provider, &dest_constraints, &ndest_constraints, 1403 NULL, NULL, NULL) != 0) { 1404 error_f("failed to parse constraints"); 1405 sshbuf_reset(e->request); 1406 goto out; 1407 } 1408 dump_dest_constraints(__func__, dest_constraints, ndest_constraints); 1409 1410 if (sk_provider != NULL) { 1411 if (!sshkey_is_sk(k)) { 1412 error("Cannot add provider: %s is not an " 1413 "authenticator-hosted key", sshkey_type(k)); 1414 goto out; 1415 } 1416 if (strcasecmp(sk_provider, "internal") == 0) { 1417 debug_f("internal provider"); 1418 } else { 1419 if (socket_is_remote(e) && !remote_add_provider) { 1420 verbose("failed add of SK provider \"%.100s\": " 1421 "remote addition of providers is disabled", 1422 sk_provider); 1423 goto out; 1424 } 1425 if (realpath(sk_provider, canonical_provider) == NULL) { 1426 verbose("failed provider \"%.100s\": " 1427 "realpath: %s", sk_provider, 1428 strerror(errno)); 1429 goto out; 1430 } 1431 free(sk_provider); 1432 sk_provider = xstrdup(canonical_provider); 1433 if (match_pattern_list(sk_provider, 1434 allowed_providers, 0) != 1) { 1435 error("Refusing add key: " 1436 "provider %s not allowed", sk_provider); 1437 goto out; 1438 } 1439 } 1440 } 1441 if ((r = sshkey_shield_private(k)) != 0) { 1442 error_fr(r, "shield private"); 1443 goto out; 1444 } 1445 if (lifetime && !death) 1446 death = monotime() + lifetime; 1447 if ((id = lookup_identity(k)) == NULL) { 1448 id = xcalloc(1, sizeof(Identity)); 1449 TAILQ_INSERT_TAIL(&idtab->idlist, id, next); 1450 /* Increment the number of identities. */ 1451 idtab->nentries++; 1452 } else { 1453 /* identity not visible, do not update */ 1454 if (identity_permitted(id, e, NULL, NULL, NULL) != 0) 1455 goto out; /* error already logged */ 1456 /* key state might have been updated */ 1457 sshkey_free(id->key); 1458 free(id->comment); 1459 free(id->sk_provider); 1460 free_dest_constraints(id->dest_constraints, 1461 id->ndest_constraints); 1462 } 1463 /* success */ 1464 id->key = k; 1465 id->comment = comment; 1466 id->death = death; 1467 id->confirm = confirm; 1468 id->sk_provider = sk_provider; 1469 id->dest_constraints = dest_constraints; 1470 id->ndest_constraints = ndest_constraints; 1471 1472 if ((fp = sshkey_fingerprint(k, SSH_FP_HASH_DEFAULT, 1473 SSH_FP_DEFAULT)) == NULL) 1474 fatal_f("sshkey_fingerprint failed"); 1475 debug_f("add %s %s \"%.100s\" (life: %u) (confirm: %u) " 1476 "(provider: %s) (destination constraints: %zu)", 1477 sshkey_ssh_name(k), fp, comment, seconds, confirm, 1478 sk_provider == NULL ? "none" : sk_provider, ndest_constraints); 1479 free(fp); 1480 /* transferred */ 1481 k = NULL; 1482 comment = NULL; 1483 sk_provider = NULL; 1484 dest_constraints = NULL; 1485 ndest_constraints = 0; 1486 success = 1; 1487 out: 1488 free(sk_provider); 1489 free(comment); 1490 sshkey_free(k); 1491 free_dest_constraints(dest_constraints, ndest_constraints); 1492 send_status(e, success); 1493 } 1494 1495 /* XXX todo: encrypt sensitive data with passphrase */ 1496 static void 1497 process_lock_agent(SocketEntry *e, int lock) 1498 { 1499 int r, success = 0, delay; 1500 char *passwd; 1501 u_char passwdhash[LOCK_SIZE]; 1502 static u_int fail_count = 0; 1503 size_t pwlen; 1504 1505 debug2_f("entering"); 1506 /* 1507 * This is deliberately fatal: the user has requested that we lock, 1508 * but we can't parse their request properly. The only safe thing to 1509 * do is abort. 1510 */ 1511 if ((r = sshbuf_get_cstring(e->request, &passwd, &pwlen)) != 0) 1512 fatal_fr(r, "parse"); 1513 if (pwlen == 0) { 1514 debug("empty password not supported"); 1515 } else if (locked && !lock) { 1516 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 1517 passwdhash, sizeof(passwdhash), LOCK_ROUNDS) < 0) 1518 fatal("bcrypt_pbkdf"); 1519 if (timingsafe_bcmp(passwdhash, lock_pwhash, LOCK_SIZE) == 0) { 1520 debug("agent unlocked"); 1521 locked = 0; 1522 fail_count = 0; 1523 explicit_bzero(lock_pwhash, sizeof(lock_pwhash)); 1524 success = 1; 1525 } else { 1526 /* delay in 0.1s increments up to 10s */ 1527 if (fail_count < 100) 1528 fail_count++; 1529 delay = 100000 * fail_count; 1530 debug("unlock failed, delaying %0.1lf seconds", 1531 (double)delay/1000000); 1532 usleep(delay); 1533 } 1534 explicit_bzero(passwdhash, sizeof(passwdhash)); 1535 } else if (!locked && lock) { 1536 debug("agent locked"); 1537 locked = 1; 1538 arc4random_buf(lock_salt, sizeof(lock_salt)); 1539 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 1540 lock_pwhash, sizeof(lock_pwhash), LOCK_ROUNDS) < 0) 1541 fatal("bcrypt_pbkdf"); 1542 success = 1; 1543 } 1544 freezero(passwd, pwlen); 1545 send_status(e, success); 1546 } 1547 1548 static void 1549 no_identities(SocketEntry *e) 1550 { 1551 struct sshbuf *msg; 1552 int r; 1553 1554 if ((msg = sshbuf_new()) == NULL) 1555 fatal_f("sshbuf_new failed"); 1556 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 1557 (r = sshbuf_put_u32(msg, 0)) != 0 || 1558 (r = sshbuf_put_stringb(e->output, msg)) != 0) 1559 fatal_fr(r, "compose"); 1560 sshbuf_free(msg); 1561 } 1562 1563 #ifdef ENABLE_PKCS11 1564 /* Add an identity to idlist; takes ownership of 'key' and 'comment' */ 1565 static void 1566 add_p11_identity(struct sshkey *key, char *comment, const char *provider, 1567 time_t death, u_int confirm, struct dest_constraint *dest_constraints, 1568 size_t ndest_constraints) 1569 { 1570 Identity *id; 1571 1572 if (lookup_identity(key) != NULL) { 1573 sshkey_free(key); 1574 free(comment); 1575 return; 1576 } 1577 id = xcalloc(1, sizeof(Identity)); 1578 id->key = key; 1579 id->comment = comment; 1580 id->provider = xstrdup(provider); 1581 id->death = death; 1582 id->confirm = confirm; 1583 id->dest_constraints = dup_dest_constraints(dest_constraints, 1584 ndest_constraints); 1585 id->ndest_constraints = ndest_constraints; 1586 TAILQ_INSERT_TAIL(&idtab->idlist, id, next); 1587 idtab->nentries++; 1588 } 1589 1590 static void 1591 process_add_smartcard_key(SocketEntry *e) 1592 { 1593 char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX]; 1594 char **comments = NULL; 1595 int r, i, count = 0, success = 0, confirm = 0; 1596 u_int seconds = 0; 1597 time_t death = 0; 1598 struct sshkey **keys = NULL, *k; 1599 struct dest_constraint *dest_constraints = NULL; 1600 size_t j, ndest_constraints = 0, ncerts = 0; 1601 struct sshkey **certs = NULL; 1602 int cert_only = 0; 1603 1604 debug2_f("entering"); 1605 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 1606 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) { 1607 error_fr(r, "parse"); 1608 goto send; 1609 } 1610 if (parse_key_constraints(e->request, NULL, &death, &seconds, &confirm, 1611 NULL, &dest_constraints, &ndest_constraints, &cert_only, 1612 &ncerts, &certs) != 0) { 1613 error_f("failed to parse constraints"); 1614 goto send; 1615 } 1616 dump_dest_constraints(__func__, dest_constraints, ndest_constraints); 1617 if (socket_is_remote(e) && !remote_add_provider) { 1618 verbose("failed PKCS#11 add of \"%.100s\": remote addition of " 1619 "providers is disabled", provider); 1620 goto send; 1621 } 1622 if (realpath(provider, canonical_provider) == NULL) { 1623 verbose("failed PKCS#11 add of \"%.100s\": realpath: %s", 1624 provider, strerror(errno)); 1625 goto send; 1626 } 1627 if (match_pattern_list(canonical_provider, allowed_providers, 0) != 1) { 1628 verbose("refusing PKCS#11 add of \"%.100s\": " 1629 "provider not allowed", canonical_provider); 1630 goto send; 1631 } 1632 debug_f("add %.100s", canonical_provider); 1633 if (lifetime && !death) 1634 death = monotime() + lifetime; 1635 1636 count = pkcs11_add_provider(canonical_provider, pin, &keys, &comments); 1637 for (i = 0; i < count; i++) { 1638 if (comments[i] == NULL || comments[i][0] == '\0') { 1639 free(comments[i]); 1640 comments[i] = xstrdup(canonical_provider); 1641 } 1642 for (j = 0; j < ncerts; j++) { 1643 if (!sshkey_is_cert(certs[j])) 1644 continue; 1645 if (!sshkey_equal_public(keys[i], certs[j])) 1646 continue; 1647 if (pkcs11_make_cert(keys[i], certs[j], &k) != 0) 1648 continue; 1649 add_p11_identity(k, xstrdup(comments[i]), 1650 canonical_provider, death, confirm, 1651 dest_constraints, ndest_constraints); 1652 success = 1; 1653 } 1654 if (!cert_only && lookup_identity(keys[i]) == NULL) { 1655 add_p11_identity(keys[i], comments[i], 1656 canonical_provider, death, confirm, 1657 dest_constraints, ndest_constraints); 1658 keys[i] = NULL; /* transferred */ 1659 comments[i] = NULL; /* transferred */ 1660 success = 1; 1661 } 1662 /* XXX update constraints for existing keys */ 1663 sshkey_free(keys[i]); 1664 free(comments[i]); 1665 } 1666 send: 1667 free(pin); 1668 free(provider); 1669 free(keys); 1670 free(comments); 1671 free_dest_constraints(dest_constraints, ndest_constraints); 1672 for (j = 0; j < ncerts; j++) 1673 sshkey_free(certs[j]); 1674 free(certs); 1675 send_status(e, success); 1676 } 1677 1678 static void 1679 process_remove_smartcard_key(SocketEntry *e) 1680 { 1681 char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX]; 1682 int r, success = 0; 1683 Identity *id, *nxt; 1684 1685 debug2_f("entering"); 1686 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 1687 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) { 1688 error_fr(r, "parse"); 1689 goto send; 1690 } 1691 free(pin); 1692 1693 if (realpath(provider, canonical_provider) == NULL) { 1694 verbose("failed PKCS#11 add of \"%.100s\": realpath: %s", 1695 provider, strerror(errno)); 1696 goto send; 1697 } 1698 1699 debug_f("remove %.100s", canonical_provider); 1700 for (id = TAILQ_FIRST(&idtab->idlist); id; id = nxt) { 1701 nxt = TAILQ_NEXT(id, next); 1702 /* Skip file--based keys */ 1703 if (id->provider == NULL) 1704 continue; 1705 if (!strcmp(canonical_provider, id->provider)) { 1706 TAILQ_REMOVE(&idtab->idlist, id, next); 1707 free_identity(id); 1708 idtab->nentries--; 1709 } 1710 } 1711 if (pkcs11_del_provider(canonical_provider) == 0) 1712 success = 1; 1713 else 1714 error_f("pkcs11_del_provider failed"); 1715 send: 1716 free(provider); 1717 send_status(e, success); 1718 } 1719 #endif /* ENABLE_PKCS11 */ 1720 1721 static int 1722 process_ext_session_bind(SocketEntry *e) 1723 { 1724 int r, sid_match, key_match; 1725 struct sshkey *key = NULL; 1726 struct sshbuf *sid = NULL, *sig = NULL; 1727 char *fp = NULL; 1728 size_t i; 1729 u_char fwd = 0; 1730 1731 debug2_f("entering"); 1732 e->session_bind_attempted = 1; 1733 if ((r = sshkey_froms(e->request, &key)) != 0 || 1734 (r = sshbuf_froms(e->request, &sid)) != 0 || 1735 (r = sshbuf_froms(e->request, &sig)) != 0 || 1736 (r = sshbuf_get_u8(e->request, &fwd)) != 0) { 1737 error_fr(r, "parse"); 1738 goto out; 1739 } 1740 if (sshbuf_len(sid) > AGENT_MAX_SID_LEN) { 1741 error_f("session ID too long"); 1742 goto out; 1743 } 1744 if ((fp = sshkey_fingerprint(key, SSH_FP_HASH_DEFAULT, 1745 SSH_FP_DEFAULT)) == NULL) 1746 fatal_f("fingerprint failed"); 1747 /* check signature with hostkey on session ID */ 1748 if ((r = sshkey_verify(key, sshbuf_ptr(sig), sshbuf_len(sig), 1749 sshbuf_ptr(sid), sshbuf_len(sid), NULL, 0, NULL)) != 0) { 1750 error_fr(r, "sshkey_verify for %s %s", sshkey_type(key), fp); 1751 goto out; 1752 } 1753 /* check whether sid/key already recorded */ 1754 for (i = 0; i < e->nsession_ids; i++) { 1755 if (!e->session_ids[i].forwarded) { 1756 error_f("attempt to bind session ID to socket " 1757 "previously bound for authentication attempt"); 1758 r = -1; 1759 goto out; 1760 } 1761 sid_match = buf_equal(sid, e->session_ids[i].sid) == 0; 1762 key_match = sshkey_equal(key, e->session_ids[i].key); 1763 if (sid_match && key_match) { 1764 debug_f("session ID already recorded for %s %s", 1765 sshkey_type(key), fp); 1766 r = 0; 1767 goto out; 1768 } else if (sid_match) { 1769 error_f("session ID recorded against different key " 1770 "for %s %s", sshkey_type(key), fp); 1771 r = -1; 1772 goto out; 1773 } 1774 /* 1775 * new sid with previously-seen key can happen, e.g. multiple 1776 * connections to the same host. 1777 */ 1778 } 1779 /* record new key/sid */ 1780 if (e->nsession_ids >= AGENT_MAX_SESSION_IDS) { 1781 error_f("too many session IDs recorded"); 1782 r = -1; 1783 goto out; 1784 } 1785 e->session_ids = xrecallocarray(e->session_ids, e->nsession_ids, 1786 e->nsession_ids + 1, sizeof(*e->session_ids)); 1787 i = e->nsession_ids++; 1788 debug_f("recorded %s %s (slot %zu of %d)", sshkey_type(key), fp, i, 1789 AGENT_MAX_SESSION_IDS); 1790 e->session_ids[i].key = key; 1791 e->session_ids[i].forwarded = fwd != 0; 1792 key = NULL; /* transferred */ 1793 /* can't transfer sid; it's refcounted and scoped to request's life */ 1794 if ((e->session_ids[i].sid = sshbuf_new()) == NULL) 1795 fatal_f("sshbuf_new"); 1796 if ((r = sshbuf_putb(e->session_ids[i].sid, sid)) != 0) 1797 fatal_fr(r, "sshbuf_putb session ID"); 1798 /* success */ 1799 r = 0; 1800 out: 1801 free(fp); 1802 sshkey_free(key); 1803 sshbuf_free(sid); 1804 sshbuf_free(sig); 1805 return r == 0 ? 1 : 0; 1806 } 1807 1808 static void 1809 process_extension(SocketEntry *e) 1810 { 1811 int r, success = 0; 1812 char *name; 1813 1814 debug2_f("entering"); 1815 if ((r = sshbuf_get_cstring(e->request, &name, NULL)) != 0) { 1816 error_fr(r, "parse"); 1817 goto send; 1818 } 1819 if (strcmp(name, "session-bind@openssh.com") == 0) 1820 success = process_ext_session_bind(e); 1821 else 1822 debug_f("unsupported extension \"%s\"", name); 1823 free(name); 1824 send: 1825 send_status(e, success); 1826 } 1827 /* 1828 * dispatch incoming message. 1829 * returns 1 on success, 0 for incomplete messages or -1 on error. 1830 */ 1831 static int 1832 process_message(u_int socknum) 1833 { 1834 u_int msg_len; 1835 u_char type; 1836 const u_char *cp; 1837 int r; 1838 SocketEntry *e; 1839 1840 if (socknum >= sockets_alloc) 1841 fatal_f("sock %u >= allocated %u", socknum, sockets_alloc); 1842 e = &sockets[socknum]; 1843 1844 if (sshbuf_len(e->input) < 5) 1845 return 0; /* Incomplete message header. */ 1846 cp = sshbuf_ptr(e->input); 1847 msg_len = PEEK_U32(cp); 1848 if (msg_len > AGENT_MAX_LEN) { 1849 debug_f("socket %u (fd=%d) message too long %u > %u", 1850 socknum, e->fd, msg_len, AGENT_MAX_LEN); 1851 return -1; 1852 } 1853 if (sshbuf_len(e->input) < msg_len + 4) 1854 return 0; /* Incomplete message body. */ 1855 1856 /* move the current input to e->request */ 1857 sshbuf_reset(e->request); 1858 if ((r = sshbuf_get_stringb(e->input, e->request)) != 0 || 1859 (r = sshbuf_get_u8(e->request, &type)) != 0) { 1860 if (r == SSH_ERR_MESSAGE_INCOMPLETE || 1861 r == SSH_ERR_STRING_TOO_LARGE) { 1862 error_fr(r, "parse"); 1863 return -1; 1864 } 1865 fatal_fr(r, "parse"); 1866 } 1867 1868 debug_f("socket %u (fd=%d) type %d", socknum, e->fd, type); 1869 1870 /* check whether agent is locked */ 1871 if (locked && type != SSH_AGENTC_UNLOCK) { 1872 sshbuf_reset(e->request); 1873 switch (type) { 1874 case SSH2_AGENTC_REQUEST_IDENTITIES: 1875 /* send empty lists */ 1876 no_identities(e); 1877 break; 1878 default: 1879 /* send a fail message for all other request types */ 1880 send_status(e, 0); 1881 } 1882 return 1; 1883 } 1884 1885 switch (type) { 1886 case SSH_AGENTC_LOCK: 1887 case SSH_AGENTC_UNLOCK: 1888 process_lock_agent(e, type == SSH_AGENTC_LOCK); 1889 break; 1890 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 1891 process_remove_all_identities(e); /* safe for !WITH_SSH1 */ 1892 break; 1893 /* ssh2 */ 1894 case SSH2_AGENTC_SIGN_REQUEST: 1895 process_sign_request2(e); 1896 break; 1897 case SSH2_AGENTC_REQUEST_IDENTITIES: 1898 process_request_identities(e); 1899 break; 1900 case SSH2_AGENTC_ADD_IDENTITY: 1901 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 1902 process_add_identity(e); 1903 break; 1904 case SSH2_AGENTC_REMOVE_IDENTITY: 1905 process_remove_identity(e); 1906 break; 1907 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 1908 process_remove_all_identities(e); 1909 break; 1910 #ifdef ENABLE_PKCS11 1911 case SSH_AGENTC_ADD_SMARTCARD_KEY: 1912 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 1913 process_add_smartcard_key(e); 1914 break; 1915 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 1916 process_remove_smartcard_key(e); 1917 break; 1918 #endif /* ENABLE_PKCS11 */ 1919 case SSH_AGENTC_EXTENSION: 1920 process_extension(e); 1921 break; 1922 default: 1923 /* Unknown message. Respond with failure. */ 1924 error("Unknown message %d", type); 1925 sshbuf_reset(e->request); 1926 send_status(e, 0); 1927 break; 1928 } 1929 return 1; 1930 } 1931 1932 static void 1933 new_socket(sock_type type, int fd) 1934 { 1935 u_int i, old_alloc, new_alloc; 1936 1937 debug_f("type = %s", type == AUTH_CONNECTION ? "CONNECTION" : 1938 (type == AUTH_SOCKET ? "SOCKET" : "UNKNOWN")); 1939 if (type == AUTH_CONNECTION) { 1940 debug("xcount %d -> %d", xcount, xcount + 1); 1941 ++xcount; 1942 } 1943 set_nonblock(fd); 1944 1945 if (fd > max_fd) 1946 max_fd = fd; 1947 1948 for (i = 0; i < sockets_alloc; i++) 1949 if (sockets[i].type == AUTH_UNUSED) { 1950 sockets[i].fd = fd; 1951 if ((sockets[i].input = sshbuf_new()) == NULL || 1952 (sockets[i].output = sshbuf_new()) == NULL || 1953 (sockets[i].request = sshbuf_new()) == NULL) 1954 fatal_f("sshbuf_new failed"); 1955 sockets[i].type = type; 1956 return; 1957 } 1958 old_alloc = sockets_alloc; 1959 new_alloc = sockets_alloc + 10; 1960 sockets = xrecallocarray(sockets, old_alloc, new_alloc, 1961 sizeof(sockets[0])); 1962 for (i = old_alloc; i < new_alloc; i++) 1963 sockets[i].type = AUTH_UNUSED; 1964 sockets_alloc = new_alloc; 1965 sockets[old_alloc].fd = fd; 1966 if ((sockets[old_alloc].input = sshbuf_new()) == NULL || 1967 (sockets[old_alloc].output = sshbuf_new()) == NULL || 1968 (sockets[old_alloc].request = sshbuf_new()) == NULL) 1969 fatal_f("sshbuf_new failed"); 1970 sockets[old_alloc].type = type; 1971 } 1972 1973 static int 1974 handle_socket_read(u_int socknum) 1975 { 1976 struct sockaddr_un sunaddr; 1977 socklen_t slen; 1978 uid_t euid; 1979 gid_t egid; 1980 int fd; 1981 1982 slen = sizeof(sunaddr); 1983 fd = accept(sockets[socknum].fd, (struct sockaddr *)&sunaddr, &slen); 1984 if (fd == -1) { 1985 error("accept from AUTH_SOCKET: %s", strerror(errno)); 1986 return -1; 1987 } 1988 if (getpeereid(fd, &euid, &egid) == -1) { 1989 error("getpeereid %d failed: %s", fd, strerror(errno)); 1990 close(fd); 1991 return -1; 1992 } 1993 if ((euid != 0) && (getuid() != euid)) { 1994 error("uid mismatch: peer euid %u != uid %u", 1995 (u_int) euid, (u_int) getuid()); 1996 close(fd); 1997 return -1; 1998 } 1999 new_socket(AUTH_CONNECTION, fd); 2000 return 0; 2001 } 2002 2003 static int 2004 handle_conn_read(u_int socknum) 2005 { 2006 char buf[AGENT_RBUF_LEN]; 2007 ssize_t len; 2008 int r; 2009 2010 if ((len = read(sockets[socknum].fd, buf, sizeof(buf))) <= 0) { 2011 if (len == -1) { 2012 if (errno == EAGAIN || errno == EINTR) 2013 return 0; 2014 error_f("read error on socket %u (fd %d): %s", 2015 socknum, sockets[socknum].fd, strerror(errno)); 2016 } 2017 return -1; 2018 } 2019 if ((r = sshbuf_put(sockets[socknum].input, buf, len)) != 0) 2020 fatal_fr(r, "compose"); 2021 explicit_bzero(buf, sizeof(buf)); 2022 for (;;) { 2023 if ((r = process_message(socknum)) == -1) 2024 return -1; 2025 else if (r == 0) 2026 break; 2027 } 2028 return 0; 2029 } 2030 2031 static int 2032 handle_conn_write(u_int socknum) 2033 { 2034 ssize_t len; 2035 int r; 2036 2037 if (sshbuf_len(sockets[socknum].output) == 0) 2038 return 0; /* shouldn't happen */ 2039 if ((len = write(sockets[socknum].fd, 2040 sshbuf_ptr(sockets[socknum].output), 2041 sshbuf_len(sockets[socknum].output))) <= 0) { 2042 if (len == -1) { 2043 if (errno == EAGAIN || errno == EINTR) 2044 return 0; 2045 error_f("read error on socket %u (fd %d): %s", 2046 socknum, sockets[socknum].fd, strerror(errno)); 2047 } 2048 return -1; 2049 } 2050 if ((r = sshbuf_consume(sockets[socknum].output, len)) != 0) 2051 fatal_fr(r, "consume"); 2052 return 0; 2053 } 2054 2055 static void 2056 after_poll(struct pollfd *pfd, size_t npfd, u_int maxfds) 2057 { 2058 size_t i; 2059 u_int socknum, activefds = npfd; 2060 2061 for (i = 0; i < npfd; i++) { 2062 if (pfd[i].revents == 0) 2063 continue; 2064 /* Find sockets entry */ 2065 for (socknum = 0; socknum < sockets_alloc; socknum++) { 2066 if (sockets[socknum].type != AUTH_SOCKET && 2067 sockets[socknum].type != AUTH_CONNECTION) 2068 continue; 2069 if (pfd[i].fd == sockets[socknum].fd) 2070 break; 2071 } 2072 if (socknum >= sockets_alloc) { 2073 error_f("no socket for fd %d", pfd[i].fd); 2074 continue; 2075 } 2076 /* Process events */ 2077 switch (sockets[socknum].type) { 2078 case AUTH_SOCKET: 2079 if ((pfd[i].revents & (POLLIN|POLLERR)) == 0) 2080 break; 2081 if (npfd > maxfds) { 2082 debug3("out of fds (active %u >= limit %u); " 2083 "skipping accept", activefds, maxfds); 2084 break; 2085 } 2086 if (handle_socket_read(socknum) == 0) 2087 activefds++; 2088 break; 2089 case AUTH_CONNECTION: 2090 if ((pfd[i].revents & (POLLIN|POLLHUP|POLLERR)) != 0 && 2091 handle_conn_read(socknum) != 0) 2092 goto close_sock; 2093 if ((pfd[i].revents & (POLLOUT|POLLHUP)) != 0 && 2094 handle_conn_write(socknum) != 0) { 2095 close_sock: 2096 if (activefds == 0) 2097 fatal("activefds == 0 at close_sock"); 2098 close_socket(&sockets[socknum]); 2099 activefds--; 2100 break; 2101 } 2102 break; 2103 default: 2104 break; 2105 } 2106 } 2107 } 2108 2109 static int 2110 prepare_poll(struct pollfd **pfdp, size_t *npfdp, struct timespec *timeoutp, u_int maxfds) 2111 { 2112 struct pollfd *pfd = *pfdp; 2113 size_t i, j, npfd = 0; 2114 time_t deadline; 2115 int r; 2116 2117 /* Count active sockets */ 2118 for (i = 0; i < sockets_alloc; i++) { 2119 switch (sockets[i].type) { 2120 case AUTH_SOCKET: 2121 case AUTH_CONNECTION: 2122 npfd++; 2123 break; 2124 case AUTH_UNUSED: 2125 break; 2126 default: 2127 fatal("Unknown socket type %d", sockets[i].type); 2128 break; 2129 } 2130 } 2131 if (npfd != *npfdp && 2132 (pfd = recallocarray(pfd, *npfdp, npfd, sizeof(*pfd))) == NULL) 2133 fatal_f("recallocarray failed"); 2134 *pfdp = pfd; 2135 *npfdp = npfd; 2136 2137 for (i = j = 0; i < sockets_alloc; i++) { 2138 switch (sockets[i].type) { 2139 case AUTH_SOCKET: 2140 if (npfd > maxfds) { 2141 debug3("out of fds (active %zu >= limit %u); " 2142 "skipping arming listener", npfd, maxfds); 2143 break; 2144 } 2145 pfd[j].fd = sockets[i].fd; 2146 pfd[j].revents = 0; 2147 pfd[j].events = POLLIN; 2148 j++; 2149 break; 2150 case AUTH_CONNECTION: 2151 pfd[j].fd = sockets[i].fd; 2152 pfd[j].revents = 0; 2153 /* 2154 * Only prepare to read if we can handle a full-size 2155 * input read buffer and enqueue a max size reply.. 2156 */ 2157 if ((r = sshbuf_check_reserve(sockets[i].input, 2158 AGENT_RBUF_LEN)) == 0 && 2159 (r = sshbuf_check_reserve(sockets[i].output, 2160 AGENT_MAX_LEN)) == 0) 2161 pfd[j].events = POLLIN; 2162 else if (r != SSH_ERR_NO_BUFFER_SPACE) 2163 fatal_fr(r, "reserve"); 2164 if (sshbuf_len(sockets[i].output) > 0) 2165 pfd[j].events |= POLLOUT; 2166 j++; 2167 break; 2168 default: 2169 break; 2170 } 2171 } 2172 deadline = reaper(); 2173 if (parent_alive_interval != 0) 2174 deadline = (deadline == 0) ? parent_alive_interval : 2175 MINIMUM(deadline, parent_alive_interval); 2176 if (deadline != 0) 2177 ptimeout_deadline_sec(timeoutp, deadline); 2178 return (1); 2179 } 2180 2181 static void 2182 cleanup_socket(void) 2183 { 2184 if (cleanup_pid != 0 && getpid() != cleanup_pid) 2185 return; 2186 debug_f("cleanup"); 2187 if (socket_name[0]) 2188 unlink(socket_name); 2189 if (socket_dir[0]) 2190 rmdir(socket_dir); 2191 } 2192 2193 void 2194 cleanup_exit(int i) 2195 { 2196 cleanup_socket(); 2197 #ifdef ENABLE_PKCS11 2198 pkcs11_terminate(); 2199 #endif 2200 _exit(i); 2201 } 2202 2203 static void 2204 cleanup_handler(int sig) 2205 { 2206 signalled_exit = sig; 2207 } 2208 2209 static void 2210 keydrop_handler(int sig) 2211 { 2212 signalled_keydrop = sig; 2213 } 2214 2215 static void 2216 check_parent_exists(void) 2217 { 2218 /* 2219 * If our parent has exited then getppid() will return (pid_t)1, 2220 * so testing for that should be safe. 2221 */ 2222 if (parent_pid != -1 && getppid() != parent_pid) { 2223 /* printf("Parent has died - Authentication agent exiting.\n"); */ 2224 cleanup_socket(); 2225 _exit(2); 2226 } 2227 } 2228 2229 static void 2230 usage(void) 2231 { 2232 fprintf(stderr, 2233 "usage: ssh-agent [-c | -s] [-Ddx] [-a bind_address] [-E fingerprint_hash]\n" 2234 " [-O option] [-P allowed_providers] [-t life]\n" 2235 " ssh-agent [-a bind_address] [-E fingerprint_hash] [-O option]\n" 2236 " [-P allowed_providers] [-t life] command [arg ...]\n" 2237 " ssh-agent [-c | -s] -k\n"); 2238 exit(1); 2239 } 2240 2241 int 2242 main(int ac, char **av) 2243 { 2244 int c_flag = 0, d_flag = 0, D_flag = 0, k_flag = 0, s_flag = 0; 2245 int sock = -1, ch, result, saved_errno; 2246 char *shell, *format, *fdstr, *pidstr, *agentsocket = NULL; 2247 const char *errstr = NULL; 2248 const char *ccp; 2249 #ifdef HAVE_SETRLIMIT 2250 struct rlimit rlim; 2251 #endif 2252 extern int optind; 2253 extern char *optarg; 2254 pid_t pid; 2255 char pidstrbuf[1 + 3 * sizeof pid]; 2256 size_t len; 2257 mode_t prev_mask; 2258 struct timespec timeout; 2259 struct pollfd *pfd = NULL; 2260 size_t npfd = 0; 2261 u_int maxfds; 2262 sigset_t nsigset, osigset; 2263 2264 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 2265 sanitise_stdfd(); 2266 2267 /* drop */ 2268 (void)setegid(getgid()); 2269 (void)setgid(getgid()); 2270 setuid(geteuid()); 2271 2272 platform_disable_tracing(0); /* strict=no */ 2273 2274 #ifdef RLIMIT_NOFILE 2275 if (getrlimit(RLIMIT_NOFILE, &rlim) == -1) 2276 fatal("%s: getrlimit: %s", __progname, strerror(errno)); 2277 #endif 2278 2279 __progname = ssh_get_progname(av[0]); 2280 seed_rng(); 2281 2282 while ((ch = getopt(ac, av, "cDdksE:a:O:P:t:x")) != -1) { 2283 switch (ch) { 2284 case 'E': 2285 fingerprint_hash = ssh_digest_alg_by_name(optarg); 2286 if (fingerprint_hash == -1) 2287 fatal("Invalid hash algorithm \"%s\"", optarg); 2288 break; 2289 case 'c': 2290 if (s_flag) 2291 usage(); 2292 c_flag++; 2293 break; 2294 case 'k': 2295 k_flag++; 2296 break; 2297 case 'O': 2298 if (strcmp(optarg, "no-restrict-websafe") == 0) 2299 restrict_websafe = 0; 2300 else if (strcmp(optarg, "allow-remote-pkcs11") == 0) 2301 remote_add_provider = 1; 2302 else if ((ccp = strprefix(optarg, 2303 "websafe-allow=", 0)) != NULL) { 2304 if (websafe_allowlist != NULL) 2305 fatal("websafe-allow already set"); 2306 websafe_allowlist = xstrdup(ccp); 2307 } else 2308 fatal("Unknown -O option"); 2309 break; 2310 case 'P': 2311 if (allowed_providers != NULL) 2312 fatal("-P option already specified"); 2313 allowed_providers = xstrdup(optarg); 2314 break; 2315 case 's': 2316 if (c_flag) 2317 usage(); 2318 s_flag++; 2319 break; 2320 case 'd': 2321 if (d_flag || D_flag) 2322 usage(); 2323 d_flag++; 2324 break; 2325 case 'D': 2326 if (d_flag || D_flag) 2327 usage(); 2328 D_flag++; 2329 break; 2330 case 'a': 2331 agentsocket = optarg; 2332 break; 2333 case 't': 2334 if ((lifetime = convtime(optarg)) == -1) { 2335 fprintf(stderr, "Invalid lifetime\n"); 2336 usage(); 2337 } 2338 break; 2339 case 'x': 2340 xcount = 0; 2341 break; 2342 default: 2343 usage(); 2344 } 2345 } 2346 ac -= optind; 2347 av += optind; 2348 2349 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag || D_flag)) 2350 usage(); 2351 2352 if (allowed_providers == NULL) 2353 allowed_providers = xstrdup(DEFAULT_ALLOWED_PROVIDERS); 2354 if (websafe_allowlist == NULL) 2355 websafe_allowlist = xstrdup(DEFAULT_WEBSAFE_ALLOWLIST); 2356 2357 if (ac == 0 && !c_flag && !s_flag) { 2358 shell = getenv("SHELL"); 2359 if (shell != NULL && (len = strlen(shell)) > 2 && 2360 strncmp(shell + len - 3, "csh", 3) == 0) 2361 c_flag = 1; 2362 } 2363 if (k_flag) { 2364 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 2365 if (pidstr == NULL) { 2366 fprintf(stderr, "%s not set, cannot kill agent\n", 2367 SSH_AGENTPID_ENV_NAME); 2368 exit(1); 2369 } 2370 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr); 2371 if (errstr) { 2372 fprintf(stderr, 2373 "%s=\"%s\", which is not a good PID: %s\n", 2374 SSH_AGENTPID_ENV_NAME, pidstr, errstr); 2375 exit(1); 2376 } 2377 if (kill(pid, SIGTERM) == -1) { 2378 perror("kill"); 2379 exit(1); 2380 } 2381 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 2382 printf(format, SSH_AUTHSOCKET_ENV_NAME); 2383 printf(format, SSH_AGENTPID_ENV_NAME); 2384 printf("echo Agent pid %ld killed;\n", (long)pid); 2385 exit(0); 2386 } 2387 2388 /* 2389 * Minimum file descriptors: 2390 * stdio (3) + listener (1) + syslog (1 maybe) + connection (1) + 2391 * a few spare for libc / stack protectors / sanitisers, etc. 2392 */ 2393 #define SSH_AGENT_MIN_FDS (3+1+1+1+4) 2394 if (rlim.rlim_cur < SSH_AGENT_MIN_FDS) 2395 fatal("%s: file descriptor rlimit %lld too low (minimum %u)", 2396 __progname, (long long)rlim.rlim_cur, SSH_AGENT_MIN_FDS); 2397 maxfds = rlim.rlim_cur - SSH_AGENT_MIN_FDS; 2398 2399 parent_pid = getpid(); 2400 2401 /* Has the socket been provided via socket activation? */ 2402 if (agentsocket == NULL && ac == 0 && (d_flag || D_flag) && 2403 (pidstr = getenv("LISTEN_PID")) != NULL && 2404 (fdstr = getenv("LISTEN_FDS")) != NULL) { 2405 if (strcmp(fdstr, "1") != 0) { 2406 fatal("unexpected LISTEN_FDS contents " 2407 "(want: \"1\" got\"%s\"", fdstr); 2408 } 2409 if (fcntl(3, F_GETFL) == -1) 2410 fatal("LISTEN_FDS set but fd 3 unavailable"); 2411 pid = (int)strtonum(pidstr, 1, INT_MAX, &errstr); 2412 if (errstr != NULL) 2413 fatal("invalid LISTEN_PID: %s", errstr); 2414 if (pid != getpid()) 2415 fatal("bad LISTEN_PID: %d vs pid %d", pid, getpid()); 2416 debug("using socket activation on fd=3"); 2417 sock = 3; 2418 } 2419 2420 /* Otherwise, create private directory for agent socket */ 2421 if (sock == -1) { 2422 if (agentsocket == NULL) { 2423 mktemp_proto(socket_dir, sizeof(socket_dir)); 2424 if (mkdtemp(socket_dir) == NULL) { 2425 perror("mkdtemp: private socket dir"); 2426 exit(1); 2427 } 2428 snprintf(socket_name, sizeof socket_name, 2429 "%s/agent.%ld", socket_dir, 2430 (long)parent_pid); 2431 } else { 2432 /* Try to use specified agent socket */ 2433 socket_dir[0] = '\0'; 2434 strlcpy(socket_name, agentsocket, sizeof socket_name); 2435 } 2436 } 2437 2438 closefrom(sock == -1 ? STDERR_FILENO + 1 : sock + 1); 2439 2440 /* 2441 * Create socket early so it will exist before command gets run from 2442 * the parent. 2443 */ 2444 if (sock == -1) { 2445 prev_mask = umask(0177); 2446 sock = unix_listener(socket_name, SSH_LISTEN_BACKLOG, 0); 2447 if (sock < 0) { 2448 /* XXX - unix_listener() calls error() not perror() */ 2449 *socket_name = '\0'; /* Don't unlink existing file */ 2450 cleanup_exit(1); 2451 } 2452 umask(prev_mask); 2453 } 2454 2455 /* 2456 * Fork, and have the parent execute the command, if any, or present 2457 * the socket data. The child continues as the authentication agent. 2458 */ 2459 if (D_flag || d_flag) { 2460 log_init(__progname, 2461 d_flag ? SYSLOG_LEVEL_DEBUG3 : SYSLOG_LEVEL_INFO, 2462 SYSLOG_FACILITY_AUTH, 1); 2463 if (socket_name[0] != '\0') { 2464 format = c_flag ? 2465 "setenv %s %s;\n" : "%s=%s; export %s;\n"; 2466 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 2467 SSH_AUTHSOCKET_ENV_NAME); 2468 printf("echo Agent pid %ld;\n", (long)parent_pid); 2469 fflush(stdout); 2470 } 2471 goto skip; 2472 } 2473 pid = fork(); 2474 if (pid == -1) { 2475 perror("fork"); 2476 cleanup_exit(1); 2477 } 2478 if (pid != 0) { /* Parent - execute the given command. */ 2479 close(sock); 2480 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 2481 if (ac == 0) { 2482 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 2483 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 2484 SSH_AUTHSOCKET_ENV_NAME); 2485 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 2486 SSH_AGENTPID_ENV_NAME); 2487 printf("echo Agent pid %ld;\n", (long)pid); 2488 exit(0); 2489 } 2490 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 2491 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 2492 perror("setenv"); 2493 exit(1); 2494 } 2495 execvp(av[0], av); 2496 perror(av[0]); 2497 exit(1); 2498 } 2499 /* child */ 2500 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 2501 2502 if (setsid() == -1) { 2503 error("setsid: %s", strerror(errno)); 2504 cleanup_exit(1); 2505 } 2506 2507 (void)chdir("/"); 2508 if (stdfd_devnull(1, 1, 1) == -1) 2509 error_f("stdfd_devnull failed"); 2510 2511 #ifdef HAVE_SETRLIMIT 2512 /* deny core dumps, since memory contains unencrypted private keys */ 2513 rlim.rlim_cur = rlim.rlim_max = 0; 2514 if (setrlimit(RLIMIT_CORE, &rlim) == -1) { 2515 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 2516 cleanup_exit(1); 2517 } 2518 #endif 2519 2520 skip: 2521 2522 cleanup_pid = getpid(); 2523 2524 #ifdef ENABLE_PKCS11 2525 pkcs11_init(0); 2526 #endif 2527 new_socket(AUTH_SOCKET, sock); 2528 if (ac > 0) 2529 parent_alive_interval = 10; 2530 idtab_init(); 2531 ssh_signal(SIGPIPE, SIG_IGN); 2532 ssh_signal(SIGINT, (d_flag | D_flag) ? cleanup_handler : SIG_IGN); 2533 ssh_signal(SIGHUP, cleanup_handler); 2534 ssh_signal(SIGTERM, cleanup_handler); 2535 ssh_signal(SIGUSR1, keydrop_handler); 2536 2537 sigemptyset(&nsigset); 2538 sigaddset(&nsigset, SIGINT); 2539 sigaddset(&nsigset, SIGHUP); 2540 sigaddset(&nsigset, SIGTERM); 2541 sigaddset(&nsigset, SIGUSR1); 2542 2543 if (pledge("stdio rpath cpath unix id proc exec", NULL) == -1) 2544 fatal("%s: pledge: %s", __progname, strerror(errno)); 2545 platform_pledge_agent(); 2546 2547 while (1) { 2548 sigprocmask(SIG_BLOCK, &nsigset, &osigset); 2549 if (signalled_exit != 0) { 2550 logit("exiting on signal %d", (int)signalled_exit); 2551 cleanup_exit(2); 2552 } 2553 if (signalled_keydrop) { 2554 logit("signal %d received; removing all keys", 2555 signalled_keydrop); 2556 remove_all_identities(); 2557 signalled_keydrop = 0; 2558 } 2559 ptimeout_init(&timeout); 2560 prepare_poll(&pfd, &npfd, &timeout, maxfds); 2561 result = ppoll(pfd, npfd, ptimeout_get_tsp(&timeout), &osigset); 2562 sigprocmask(SIG_SETMASK, &osigset, NULL); 2563 saved_errno = errno; 2564 if (parent_alive_interval != 0) 2565 check_parent_exists(); 2566 (void) reaper(); /* remove expired keys */ 2567 if (result == -1) { 2568 if (saved_errno == EINTR) 2569 continue; 2570 fatal("poll: %s", strerror(saved_errno)); 2571 } else if (result > 0) 2572 after_poll(pfd, npfd, maxfds); 2573 } 2574 /* NOTREACHED */ 2575 } 2576