1 /* $OpenBSD: ssh-agent.c,v 1.313 2025/08/29 03:50:38 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 #include <sys/time.h> 45 #include <sys/un.h> 46 #include "openbsd-compat/sys-queue.h" 47 48 #ifdef WITH_OPENSSL 49 #include <openssl/evp.h> 50 #include "openbsd-compat/openssl-compat.h" 51 #endif 52 53 #include <errno.h> 54 #include <fcntl.h> 55 #include <limits.h> 56 #include <paths.h> 57 #include <poll.h> 58 #include <signal.h> 59 #include <stdarg.h> 60 #include <stdio.h> 61 #include <stdlib.h> 62 #include <time.h> 63 #include <string.h> 64 #include <unistd.h> 65 #include <util.h> 66 67 #include "xmalloc.h" 68 #include "ssh.h" 69 #include "ssh2.h" 70 #include "sshbuf.h" 71 #include "sshkey.h" 72 #include "authfd.h" 73 #include "log.h" 74 #include "misc.h" 75 #include "digest.h" 76 #include "ssherr.h" 77 #include "match.h" 78 #include "msg.h" 79 #include "pathnames.h" 80 #include "ssh-pkcs11.h" 81 #include "sk-api.h" 82 #include "myproposal.h" 83 84 #ifndef DEFAULT_ALLOWED_PROVIDERS 85 # define DEFAULT_ALLOWED_PROVIDERS "/usr/lib*/*,/usr/local/lib*/*" 86 #endif 87 #ifndef DEFAULT_WEBSAFE_ALLOWLIST 88 # define DEFAULT_WEBSAFE_ALLOWLIST "ssh:*" 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 /* Maximum number of recorded session IDs/hostkeys per connection */ 96 #define AGENT_MAX_SESSION_IDS 16 97 /* Maximum size of session ID */ 98 #define AGENT_MAX_SID_LEN 128 99 /* Maximum number of destination constraints to accept on a key */ 100 #define AGENT_MAX_DEST_CONSTRAINTS 1024 101 /* Maximum number of associated certificate constraints to accept on a key */ 102 #define AGENT_MAX_EXT_CERTS 1024 103 104 /* XXX store hostkey_sid in a refcounted tree */ 105 106 typedef enum { 107 AUTH_UNUSED = 0, 108 AUTH_SOCKET = 1, 109 AUTH_CONNECTION = 2, 110 } sock_type; 111 112 struct hostkey_sid { 113 struct sshkey *key; 114 struct sshbuf *sid; 115 int forwarded; 116 }; 117 118 typedef struct socket_entry { 119 int fd; 120 sock_type type; 121 struct sshbuf *input; 122 struct sshbuf *output; 123 struct sshbuf *request; 124 size_t nsession_ids; 125 struct hostkey_sid *session_ids; 126 int session_bind_attempted; 127 } SocketEntry; 128 129 u_int sockets_alloc = 0; 130 SocketEntry *sockets = NULL; 131 132 typedef struct identity { 133 TAILQ_ENTRY(identity) next; 134 struct sshkey *key; 135 char *comment; 136 char *provider; 137 time_t death; 138 u_int confirm; 139 char *sk_provider; 140 struct dest_constraint *dest_constraints; 141 size_t ndest_constraints; 142 } Identity; 143 144 struct idtable { 145 int nentries; 146 TAILQ_HEAD(idqueue, identity) idlist; 147 }; 148 149 /* private key table */ 150 struct idtable *idtab; 151 152 int max_fd = 0; 153 154 /* pid of shell == parent of agent */ 155 pid_t parent_pid = -1; 156 time_t parent_alive_interval = 0; 157 158 static sig_atomic_t signalled_exit; 159 static sig_atomic_t signalled_keydrop; 160 161 /* pid of process for which cleanup_socket is applicable */ 162 pid_t cleanup_pid = 0; 163 164 /* pathname and directory for AUTH_SOCKET */ 165 char socket_name[PATH_MAX]; 166 char socket_dir[PATH_MAX]; 167 168 /* Pattern-list of allowed PKCS#11/Security key paths */ 169 static char *allowed_providers; 170 171 /* 172 * Allows PKCS11 providers or SK keys that use non-internal providers to 173 * be added over a remote connection (identified by session-bind@openssh.com). 174 */ 175 static int remote_add_provider; 176 177 /* locking */ 178 #define LOCK_SIZE 32 179 #define LOCK_SALT_SIZE 16 180 #define LOCK_ROUNDS 1 181 int locked = 0; 182 u_char lock_pwhash[LOCK_SIZE]; 183 u_char lock_salt[LOCK_SALT_SIZE]; 184 185 extern char *__progname; 186 187 /* Default lifetime in seconds (0 == forever) */ 188 static int lifetime = 0; 189 190 static int fingerprint_hash = SSH_FP_HASH_DEFAULT; 191 192 /* Refuse signing of non-SSH messages for web-origin FIDO keys */ 193 static int restrict_websafe = 1; 194 static char *websafe_allowlist; 195 196 /* 197 * Client connection count; incremented in new_socket() and decremented in 198 * close_socket(). When it reaches 0, ssh-agent will exit. Since it is 199 * normally initialized to 1, it will never reach 0. However, if the -x 200 * option is specified, it is initialized to 0 in main(); in that case, 201 * ssh-agent will exit as soon as it has had at least one client but no 202 * longer has any. 203 */ 204 static int xcount = 1; 205 206 static void 207 close_socket(SocketEntry *e) 208 { 209 size_t i; 210 int last = 0; 211 212 if (e->type == AUTH_CONNECTION) { 213 debug("xcount %d -> %d", xcount, xcount - 1); 214 if (--xcount == 0) 215 last = 1; 216 } 217 close(e->fd); 218 sshbuf_free(e->input); 219 sshbuf_free(e->output); 220 sshbuf_free(e->request); 221 for (i = 0; i < e->nsession_ids; i++) { 222 sshkey_free(e->session_ids[i].key); 223 sshbuf_free(e->session_ids[i].sid); 224 } 225 free(e->session_ids); 226 memset(e, '\0', sizeof(*e)); 227 e->fd = -1; 228 e->type = AUTH_UNUSED; 229 if (last) 230 cleanup_exit(0); 231 } 232 233 static void 234 idtab_init(void) 235 { 236 idtab = xcalloc(1, sizeof(*idtab)); 237 TAILQ_INIT(&idtab->idlist); 238 idtab->nentries = 0; 239 } 240 241 static void 242 free_dest_constraint_hop(struct dest_constraint_hop *dch) 243 { 244 u_int i; 245 246 if (dch == NULL) 247 return; 248 free(dch->user); 249 free(dch->hostname); 250 for (i = 0; i < dch->nkeys; i++) 251 sshkey_free(dch->keys[i]); 252 free(dch->keys); 253 free(dch->key_is_ca); 254 } 255 256 static void 257 free_dest_constraints(struct dest_constraint *dcs, size_t ndcs) 258 { 259 size_t i; 260 261 for (i = 0; i < ndcs; i++) { 262 free_dest_constraint_hop(&dcs[i].from); 263 free_dest_constraint_hop(&dcs[i].to); 264 } 265 free(dcs); 266 } 267 268 #ifdef ENABLE_PKCS11 269 static void 270 dup_dest_constraint_hop(const struct dest_constraint_hop *dch, 271 struct dest_constraint_hop *out) 272 { 273 u_int i; 274 int r; 275 276 out->user = dch->user == NULL ? NULL : xstrdup(dch->user); 277 out->hostname = dch->hostname == NULL ? NULL : xstrdup(dch->hostname); 278 out->is_ca = dch->is_ca; 279 out->nkeys = dch->nkeys; 280 out->keys = out->nkeys == 0 ? NULL : 281 xcalloc(out->nkeys, sizeof(*out->keys)); 282 out->key_is_ca = out->nkeys == 0 ? NULL : 283 xcalloc(out->nkeys, sizeof(*out->key_is_ca)); 284 for (i = 0; i < dch->nkeys; i++) { 285 if (dch->keys[i] != NULL && 286 (r = sshkey_from_private(dch->keys[i], 287 &(out->keys[i]))) != 0) 288 fatal_fr(r, "copy key"); 289 out->key_is_ca[i] = dch->key_is_ca[i]; 290 } 291 } 292 293 static struct dest_constraint * 294 dup_dest_constraints(const struct dest_constraint *dcs, size_t ndcs) 295 { 296 size_t i; 297 struct dest_constraint *ret; 298 299 if (ndcs == 0) 300 return NULL; 301 ret = xcalloc(ndcs, sizeof(*ret)); 302 for (i = 0; i < ndcs; i++) { 303 dup_dest_constraint_hop(&dcs[i].from, &ret[i].from); 304 dup_dest_constraint_hop(&dcs[i].to, &ret[i].to); 305 } 306 return ret; 307 } 308 #endif /* ENABLE_PKCS11 */ 309 310 #ifdef DEBUG_CONSTRAINTS 311 static void 312 dump_dest_constraint_hop(const struct dest_constraint_hop *dch) 313 { 314 u_int i; 315 char *fp; 316 317 debug_f("user %s hostname %s is_ca %d nkeys %u", 318 dch->user == NULL ? "(null)" : dch->user, 319 dch->hostname == NULL ? "(null)" : dch->hostname, 320 dch->is_ca, dch->nkeys); 321 for (i = 0; i < dch->nkeys; i++) { 322 fp = NULL; 323 if (dch->keys[i] != NULL && 324 (fp = sshkey_fingerprint(dch->keys[i], 325 SSH_FP_HASH_DEFAULT, SSH_FP_DEFAULT)) == NULL) 326 fatal_f("fingerprint failed"); 327 debug_f("key %u/%u: %s%s%s key_is_ca %d", i, dch->nkeys, 328 dch->keys[i] == NULL ? "" : sshkey_ssh_name(dch->keys[i]), 329 dch->keys[i] == NULL ? "" : " ", 330 dch->keys[i] == NULL ? "none" : fp, 331 dch->key_is_ca[i]); 332 free(fp); 333 } 334 } 335 #endif /* DEBUG_CONSTRAINTS */ 336 337 static void 338 dump_dest_constraints(const char *context, 339 const struct dest_constraint *dcs, size_t ndcs) 340 { 341 #ifdef DEBUG_CONSTRAINTS 342 size_t i; 343 344 debug_f("%s: %zu constraints", context, ndcs); 345 for (i = 0; i < ndcs; i++) { 346 debug_f("constraint %zu / %zu: from: ", i, ndcs); 347 dump_dest_constraint_hop(&dcs[i].from); 348 debug_f("constraint %zu / %zu: to: ", i, ndcs); 349 dump_dest_constraint_hop(&dcs[i].to); 350 } 351 debug_f("done for %s", context); 352 #endif /* DEBUG_CONSTRAINTS */ 353 } 354 355 static void 356 free_identity(Identity *id) 357 { 358 sshkey_free(id->key); 359 free(id->provider); 360 free(id->comment); 361 free(id->sk_provider); 362 free_dest_constraints(id->dest_constraints, id->ndest_constraints); 363 free(id); 364 } 365 366 /* 367 * Match 'key' against the key/CA list in a destination constraint hop 368 * Returns 0 on success or -1 otherwise. 369 */ 370 static int 371 match_key_hop(const char *tag, const struct sshkey *key, 372 const struct dest_constraint_hop *dch) 373 { 374 const char *reason = NULL; 375 const char *hostname = dch->hostname ? dch->hostname : "(ORIGIN)"; 376 u_int i; 377 char *fp; 378 379 if (key == NULL) 380 return -1; 381 /* XXX logspam */ 382 if ((fp = sshkey_fingerprint(key, SSH_FP_HASH_DEFAULT, 383 SSH_FP_DEFAULT)) == NULL) 384 fatal_f("fingerprint failed"); 385 debug3_f("%s: entering hostname %s, requested key %s %s, %u keys avail", 386 tag, hostname, sshkey_type(key), fp, dch->nkeys); 387 free(fp); 388 for (i = 0; i < dch->nkeys; i++) { 389 if (dch->keys[i] == NULL) 390 return -1; 391 /* XXX logspam */ 392 if ((fp = sshkey_fingerprint(dch->keys[i], SSH_FP_HASH_DEFAULT, 393 SSH_FP_DEFAULT)) == NULL) 394 fatal_f("fingerprint failed"); 395 debug3_f("%s: key %u: %s%s %s", tag, i, 396 dch->key_is_ca[i] ? "CA " : "", 397 sshkey_type(dch->keys[i]), fp); 398 free(fp); 399 if (!sshkey_is_cert(key)) { 400 /* plain key */ 401 if (dch->key_is_ca[i] || 402 !sshkey_equal(key, dch->keys[i])) 403 continue; 404 return 0; 405 } 406 /* certificate */ 407 if (!dch->key_is_ca[i]) 408 continue; 409 if (key->cert == NULL || key->cert->signature_key == NULL) 410 return -1; /* shouldn't happen */ 411 if (!sshkey_equal(key->cert->signature_key, dch->keys[i])) 412 continue; 413 if (sshkey_cert_check_host(key, hostname, 1, 414 SSH_ALLOWED_CA_SIGALGS, &reason) != 0) { 415 debug_f("cert %s / hostname %s rejected: %s", 416 key->cert->key_id, hostname, reason); 417 continue; 418 } 419 return 0; 420 } 421 return -1; 422 } 423 424 /* Check destination constraints on an identity against the hostkey/user */ 425 static int 426 permitted_by_dest_constraints(const struct sshkey *fromkey, 427 const struct sshkey *tokey, Identity *id, const char *user, 428 const char **hostnamep) 429 { 430 size_t i; 431 struct dest_constraint *d; 432 433 if (hostnamep != NULL) 434 *hostnamep = NULL; 435 for (i = 0; i < id->ndest_constraints; i++) { 436 d = id->dest_constraints + i; 437 /* XXX remove logspam */ 438 debug2_f("constraint %zu %s%s%s (%u keys) > %s%s%s (%u keys)", 439 i, d->from.user ? d->from.user : "", 440 d->from.user ? "@" : "", 441 d->from.hostname ? d->from.hostname : "(ORIGIN)", 442 d->from.nkeys, 443 d->to.user ? d->to.user : "", d->to.user ? "@" : "", 444 d->to.hostname ? d->to.hostname : "(ANY)", d->to.nkeys); 445 446 /* Match 'from' key */ 447 if (fromkey == NULL) { 448 /* We are matching the first hop */ 449 if (d->from.hostname != NULL || d->from.nkeys != 0) 450 continue; 451 } else if (match_key_hop("from", fromkey, &d->from) != 0) 452 continue; 453 454 /* Match 'to' key */ 455 if (tokey != NULL && match_key_hop("to", tokey, &d->to) != 0) 456 continue; 457 458 /* Match user if specified */ 459 if (d->to.user != NULL && user != NULL && 460 !match_pattern(user, d->to.user)) 461 continue; 462 463 /* successfully matched this constraint */ 464 if (hostnamep != NULL) 465 *hostnamep = d->to.hostname; 466 debug2_f("allowed for hostname %s", 467 d->to.hostname == NULL ? "*" : d->to.hostname); 468 return 0; 469 } 470 /* no match */ 471 debug2_f("%s identity \"%s\" not permitted for this destination", 472 sshkey_type(id->key), id->comment); 473 return -1; 474 } 475 476 /* 477 * Check whether hostkeys on a SocketEntry and the optionally specified user 478 * are permitted by the destination constraints on the Identity. 479 * Returns 0 on success or -1 otherwise. 480 */ 481 static int 482 identity_permitted(Identity *id, SocketEntry *e, char *user, 483 const char **forward_hostnamep, const char **last_hostnamep) 484 { 485 size_t i; 486 const char **hp; 487 struct hostkey_sid *hks; 488 const struct sshkey *fromkey = NULL; 489 const char *test_user; 490 char *fp1, *fp2; 491 492 /* XXX remove logspam */ 493 debug3_f("entering: key %s comment \"%s\", %zu socket bindings, " 494 "%zu constraints", sshkey_type(id->key), id->comment, 495 e->nsession_ids, id->ndest_constraints); 496 if (id->ndest_constraints == 0) 497 return 0; /* unconstrained */ 498 if (e->session_bind_attempted && e->nsession_ids == 0) { 499 error_f("previous session bind failed on socket"); 500 return -1; 501 } 502 if (e->nsession_ids == 0) 503 return 0; /* local use */ 504 /* 505 * Walk through the hops recorded by session_id and try to find a 506 * constraint that satisfies each. 507 */ 508 for (i = 0; i < e->nsession_ids; i++) { 509 hks = e->session_ids + i; 510 if (hks->key == NULL) 511 fatal_f("internal error: no bound key"); 512 /* XXX remove logspam */ 513 fp1 = fp2 = NULL; 514 if (fromkey != NULL && 515 (fp1 = sshkey_fingerprint(fromkey, SSH_FP_HASH_DEFAULT, 516 SSH_FP_DEFAULT)) == NULL) 517 fatal_f("fingerprint failed"); 518 if ((fp2 = sshkey_fingerprint(hks->key, SSH_FP_HASH_DEFAULT, 519 SSH_FP_DEFAULT)) == NULL) 520 fatal_f("fingerprint failed"); 521 debug3_f("socketentry fd=%d, entry %zu %s, " 522 "from hostkey %s %s to user %s hostkey %s %s", 523 e->fd, i, hks->forwarded ? "FORWARD" : "AUTH", 524 fromkey ? sshkey_type(fromkey) : "(ORIGIN)", 525 fromkey ? fp1 : "", user ? user : "(ANY)", 526 sshkey_type(hks->key), fp2); 527 free(fp1); 528 free(fp2); 529 /* 530 * Record the hostnames for the initial forwarding and 531 * the final destination. 532 */ 533 hp = NULL; 534 if (i == e->nsession_ids - 1) 535 hp = last_hostnamep; 536 else if (i == 0) 537 hp = forward_hostnamep; 538 /* Special handling for final recorded binding */ 539 test_user = NULL; 540 if (i == e->nsession_ids - 1) { 541 /* Can only check user at final hop */ 542 test_user = user; 543 /* 544 * user is only presented for signature requests. 545 * If this is the case, make sure last binding is not 546 * for a forwarding. 547 */ 548 if (hks->forwarded && user != NULL) { 549 error_f("tried to sign on forwarding hop"); 550 return -1; 551 } 552 } else if (!hks->forwarded) { 553 error_f("tried to forward though signing bind"); 554 return -1; 555 } 556 if (permitted_by_dest_constraints(fromkey, hks->key, id, 557 test_user, hp) != 0) 558 return -1; 559 fromkey = hks->key; 560 } 561 /* 562 * Another special case: if the last bound session ID was for a 563 * forwarding, and this function is not being called to check a sign 564 * request (i.e. no 'user' supplied), then only permit the key if 565 * there is a permission that would allow it to be used at another 566 * destination. This hides keys that are allowed to be used to 567 * authenticate *to* a host but not permitted for *use* beyond it. 568 */ 569 hks = &e->session_ids[e->nsession_ids - 1]; 570 if (hks->forwarded && user == NULL && 571 permitted_by_dest_constraints(hks->key, NULL, id, 572 NULL, NULL) != 0) { 573 debug3_f("key permitted at host but not after"); 574 return -1; 575 } 576 577 /* success */ 578 return 0; 579 } 580 581 static int 582 socket_is_remote(SocketEntry *e) 583 { 584 return e->session_bind_attempted || (e->nsession_ids != 0); 585 } 586 587 /* return matching private key for given public key */ 588 static Identity * 589 lookup_identity(struct sshkey *key) 590 { 591 Identity *id; 592 593 TAILQ_FOREACH(id, &idtab->idlist, next) { 594 if (sshkey_equal(key, id->key)) 595 return (id); 596 } 597 return (NULL); 598 } 599 600 /* Check confirmation of keysign request */ 601 static int 602 confirm_key(Identity *id, const char *extra) 603 { 604 char *p; 605 int ret = -1; 606 607 p = sshkey_fingerprint(id->key, fingerprint_hash, SSH_FP_DEFAULT); 608 if (p != NULL && 609 ask_permission("Allow use of key %s?\nKey fingerprint %s.%s%s", 610 id->comment, p, 611 extra == NULL ? "" : "\n", extra == NULL ? "" : extra)) 612 ret = 0; 613 free(p); 614 615 return (ret); 616 } 617 618 static void 619 send_status(SocketEntry *e, int success) 620 { 621 int r; 622 623 if ((r = sshbuf_put_u32(e->output, 1)) != 0 || 624 (r = sshbuf_put_u8(e->output, success ? 625 SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0) 626 fatal_fr(r, "compose"); 627 } 628 629 /* send list of supported public keys to 'client' */ 630 static void 631 process_request_identities(SocketEntry *e) 632 { 633 Identity *id; 634 struct sshbuf *msg, *keys; 635 int r; 636 u_int i = 0, nentries = 0; 637 char *fp; 638 639 debug2_f("entering"); 640 641 if ((msg = sshbuf_new()) == NULL || (keys = sshbuf_new()) == NULL) 642 fatal_f("sshbuf_new failed"); 643 TAILQ_FOREACH(id, &idtab->idlist, next) { 644 if ((fp = sshkey_fingerprint(id->key, SSH_FP_HASH_DEFAULT, 645 SSH_FP_DEFAULT)) == NULL) 646 fatal_f("fingerprint failed"); 647 debug_f("key %u / %u: %s %s", i++, idtab->nentries, 648 sshkey_ssh_name(id->key), fp); 649 dump_dest_constraints(__func__, 650 id->dest_constraints, id->ndest_constraints); 651 free(fp); 652 /* identity not visible, don't include in response */ 653 if (identity_permitted(id, e, NULL, NULL, NULL) != 0) 654 continue; 655 if ((r = sshkey_puts(id->key, keys)) != 0 || 656 (r = sshbuf_put_cstring(keys, id->comment)) != 0) { 657 error_fr(r, "compose key/comment"); 658 continue; 659 } 660 nentries++; 661 } 662 debug2_f("replying with %u allowed of %u available keys", 663 nentries, idtab->nentries); 664 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 665 (r = sshbuf_put_u32(msg, nentries)) != 0 || 666 (r = sshbuf_putb(msg, keys)) != 0) 667 fatal_fr(r, "compose"); 668 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 669 fatal_fr(r, "enqueue"); 670 sshbuf_free(msg); 671 sshbuf_free(keys); 672 } 673 674 675 static char * 676 agent_decode_alg(struct sshkey *key, u_int flags) 677 { 678 if (key->type == KEY_RSA) { 679 if (flags & SSH_AGENT_RSA_SHA2_256) 680 return "rsa-sha2-256"; 681 else if (flags & SSH_AGENT_RSA_SHA2_512) 682 return "rsa-sha2-512"; 683 } else if (key->type == KEY_RSA_CERT) { 684 if (flags & SSH_AGENT_RSA_SHA2_256) 685 return "rsa-sha2-256-cert-v01@openssh.com"; 686 else if (flags & SSH_AGENT_RSA_SHA2_512) 687 return "rsa-sha2-512-cert-v01@openssh.com"; 688 } 689 return NULL; 690 } 691 692 /* 693 * Attempt to parse the contents of a buffer as a SSH publickey userauth 694 * request, checking its contents for consistency and matching the embedded 695 * key against the one that is being used for signing. 696 * Note: does not modify msg buffer. 697 * Optionally extract the username, session ID and/or hostkey from the request. 698 */ 699 static int 700 parse_userauth_request(struct sshbuf *msg, const struct sshkey *expected_key, 701 char **userp, struct sshbuf **sess_idp, struct sshkey **hostkeyp) 702 { 703 struct sshbuf *b = NULL, *sess_id = NULL; 704 char *user = NULL, *service = NULL, *method = NULL, *pkalg = NULL; 705 int r; 706 u_char t, sig_follows; 707 struct sshkey *mkey = NULL, *hostkey = NULL; 708 709 if (userp != NULL) 710 *userp = NULL; 711 if (sess_idp != NULL) 712 *sess_idp = NULL; 713 if (hostkeyp != NULL) 714 *hostkeyp = NULL; 715 if ((b = sshbuf_fromb(msg)) == NULL) 716 fatal_f("sshbuf_fromb"); 717 718 /* SSH userauth request */ 719 if ((r = sshbuf_froms(b, &sess_id)) != 0) 720 goto out; 721 if (sshbuf_len(sess_id) == 0) { 722 r = SSH_ERR_INVALID_FORMAT; 723 goto out; 724 } 725 if ((r = sshbuf_get_u8(b, &t)) != 0 || /* SSH2_MSG_USERAUTH_REQUEST */ 726 (r = sshbuf_get_cstring(b, &user, NULL)) != 0 || /* server user */ 727 (r = sshbuf_get_cstring(b, &service, NULL)) != 0 || /* service */ 728 (r = sshbuf_get_cstring(b, &method, NULL)) != 0 || /* method */ 729 (r = sshbuf_get_u8(b, &sig_follows)) != 0 || /* sig-follows */ 730 (r = sshbuf_get_cstring(b, &pkalg, NULL)) != 0 || /* alg */ 731 (r = sshkey_froms(b, &mkey)) != 0) /* key */ 732 goto out; 733 if (t != SSH2_MSG_USERAUTH_REQUEST || 734 sig_follows != 1 || 735 strcmp(service, "ssh-connection") != 0 || 736 !sshkey_equal(expected_key, mkey) || 737 sshkey_type_from_name(pkalg) != expected_key->type) { 738 r = SSH_ERR_INVALID_FORMAT; 739 goto out; 740 } 741 if (strcmp(method, "publickey-hostbound-v00@openssh.com") == 0) { 742 if ((r = sshkey_froms(b, &hostkey)) != 0) 743 goto out; 744 } else if (strcmp(method, "publickey") != 0) { 745 r = SSH_ERR_INVALID_FORMAT; 746 goto out; 747 } 748 if (sshbuf_len(b) != 0) { 749 r = SSH_ERR_INVALID_FORMAT; 750 goto out; 751 } 752 /* success */ 753 r = 0; 754 debug3_f("well formed userauth"); 755 if (userp != NULL) { 756 *userp = user; 757 user = NULL; 758 } 759 if (sess_idp != NULL) { 760 *sess_idp = sess_id; 761 sess_id = NULL; 762 } 763 if (hostkeyp != NULL) { 764 *hostkeyp = hostkey; 765 hostkey = NULL; 766 } 767 out: 768 sshbuf_free(b); 769 sshbuf_free(sess_id); 770 free(user); 771 free(service); 772 free(method); 773 free(pkalg); 774 sshkey_free(mkey); 775 sshkey_free(hostkey); 776 return r; 777 } 778 779 /* 780 * Attempt to parse the contents of a buffer as a SSHSIG signature request. 781 * Note: does not modify buffer. 782 */ 783 static int 784 parse_sshsig_request(struct sshbuf *msg) 785 { 786 int r; 787 struct sshbuf *b; 788 789 if ((b = sshbuf_fromb(msg)) == NULL) 790 fatal_f("sshbuf_fromb"); 791 792 if ((r = sshbuf_cmp(b, 0, "SSHSIG", 6)) != 0 || 793 (r = sshbuf_consume(b, 6)) != 0 || 794 (r = sshbuf_get_cstring(b, NULL, NULL)) != 0 || /* namespace */ 795 (r = sshbuf_get_string_direct(b, NULL, NULL)) != 0 || /* reserved */ 796 (r = sshbuf_get_cstring(b, NULL, NULL)) != 0 || /* hashalg */ 797 (r = sshbuf_get_string_direct(b, NULL, NULL)) != 0) /* H(msg) */ 798 goto out; 799 if (sshbuf_len(b) != 0) { 800 r = SSH_ERR_INVALID_FORMAT; 801 goto out; 802 } 803 /* success */ 804 r = 0; 805 out: 806 sshbuf_free(b); 807 return r; 808 } 809 810 /* 811 * This function inspects a message to be signed by a FIDO key that has a 812 * web-like application string (i.e. one that does not begin with "ssh:". 813 * It checks that the message is one of those expected for SSH operations 814 * (pubkey userauth, sshsig, CA key signing) to exclude signing challenges 815 * for the web. 816 */ 817 static int 818 check_websafe_message_contents(struct sshkey *key, struct sshbuf *data) 819 { 820 if (parse_userauth_request(data, key, NULL, NULL, NULL) == 0) { 821 debug_f("signed data matches public key userauth request"); 822 return 1; 823 } 824 if (parse_sshsig_request(data) == 0) { 825 debug_f("signed data matches SSHSIG signature request"); 826 return 1; 827 } 828 829 /* XXX check CA signature operation */ 830 831 error("web-origin key attempting to sign non-SSH message"); 832 return 0; 833 } 834 835 static int 836 buf_equal(const struct sshbuf *a, const struct sshbuf *b) 837 { 838 if (sshbuf_ptr(a) == NULL || sshbuf_ptr(b) == NULL) 839 return SSH_ERR_INVALID_ARGUMENT; 840 if (sshbuf_len(a) != sshbuf_len(b)) 841 return SSH_ERR_INVALID_FORMAT; 842 if (timingsafe_bcmp(sshbuf_ptr(a), sshbuf_ptr(b), sshbuf_len(a)) != 0) 843 return SSH_ERR_INVALID_FORMAT; 844 return 0; 845 } 846 847 /* ssh2 only */ 848 static void 849 process_sign_request2(SocketEntry *e) 850 { 851 u_char *signature = NULL; 852 size_t slen = 0; 853 u_int compat = 0, flags; 854 int r, ok = -1, retried = 0; 855 char *fp = NULL, *pin = NULL, *prompt = NULL; 856 char *user = NULL, *sig_dest = NULL; 857 const char *fwd_host = NULL, *dest_host = NULL; 858 struct sshbuf *msg = NULL, *data = NULL, *sid = NULL; 859 struct sshkey *key = NULL, *hostkey = NULL; 860 struct identity *id; 861 struct notifier_ctx *notifier = NULL; 862 863 debug_f("entering"); 864 865 if ((msg = sshbuf_new()) == NULL || (data = sshbuf_new()) == NULL) 866 fatal_f("sshbuf_new failed"); 867 if ((r = sshkey_froms(e->request, &key)) != 0 || 868 (r = sshbuf_get_stringb(e->request, data)) != 0 || 869 (r = sshbuf_get_u32(e->request, &flags)) != 0) { 870 error_fr(r, "parse"); 871 goto send; 872 } 873 874 if ((id = lookup_identity(key)) == NULL) { 875 verbose_f("%s key not found", sshkey_type(key)); 876 goto send; 877 } 878 if ((fp = sshkey_fingerprint(key, SSH_FP_HASH_DEFAULT, 879 SSH_FP_DEFAULT)) == NULL) 880 fatal_f("fingerprint failed"); 881 882 if (id->ndest_constraints != 0) { 883 if (e->nsession_ids == 0) { 884 logit_f("refusing use of destination-constrained key " 885 "to sign on unbound connection"); 886 goto send; 887 } 888 if (parse_userauth_request(data, key, &user, &sid, 889 &hostkey) != 0) { 890 logit_f("refusing use of destination-constrained key " 891 "to sign an unidentified signature"); 892 goto send; 893 } 894 /* XXX logspam */ 895 debug_f("user=%s", user); 896 if (identity_permitted(id, e, user, &fwd_host, &dest_host) != 0) 897 goto send; 898 /* XXX display fwd_host/dest_host in askpass UI */ 899 /* 900 * Ensure that the session ID is the most recent one 901 * registered on the socket - it should have been bound by 902 * ssh immediately before userauth. 903 */ 904 if (buf_equal(sid, 905 e->session_ids[e->nsession_ids - 1].sid) != 0) { 906 error_f("unexpected session ID (%zu listed) on " 907 "signature request for target user %s with " 908 "key %s %s", e->nsession_ids, user, 909 sshkey_type(id->key), fp); 910 goto send; 911 } 912 /* 913 * Ensure that the hostkey embedded in the signature matches 914 * the one most recently bound to the socket. An exception is 915 * made for the initial forwarding hop. 916 */ 917 if (e->nsession_ids > 1 && hostkey == NULL) { 918 error_f("refusing use of destination-constrained key: " 919 "no hostkey recorded in signature for forwarded " 920 "connection"); 921 goto send; 922 } 923 if (hostkey != NULL && !sshkey_equal(hostkey, 924 e->session_ids[e->nsession_ids - 1].key)) { 925 error_f("refusing use of destination-constrained key: " 926 "mismatch between hostkey in request and most " 927 "recently bound session"); 928 goto send; 929 } 930 xasprintf(&sig_dest, "public key authentication request for " 931 "user \"%s\" to listed host", user); 932 } 933 if (id->confirm && confirm_key(id, sig_dest) != 0) { 934 verbose_f("user refused key"); 935 goto send; 936 } 937 if (sshkey_is_sk(id->key)) { 938 if (restrict_websafe && 939 match_pattern_list(id->key->sk_application, 940 websafe_allowlist, 0) != 1 && 941 !check_websafe_message_contents(key, data)) { 942 /* error already logged */ 943 goto send; 944 } 945 if (id->key->sk_flags & SSH_SK_USER_PRESENCE_REQD) { 946 notifier = notify_start(0, 947 "Confirm user presence for key %s %s%s%s", 948 sshkey_type(id->key), fp, 949 sig_dest == NULL ? "" : "\n", 950 sig_dest == NULL ? "" : sig_dest); 951 } 952 } 953 retry_pin: 954 if ((r = sshkey_sign(id->key, &signature, &slen, 955 sshbuf_ptr(data), sshbuf_len(data), agent_decode_alg(key, flags), 956 id->sk_provider, pin, compat)) != 0) { 957 debug_fr(r, "sshkey_sign"); 958 if (pin == NULL && !retried && sshkey_is_sk(id->key) && 959 r == SSH_ERR_KEY_WRONG_PASSPHRASE) { 960 notify_complete(notifier, NULL); 961 notifier = NULL; 962 /* XXX include sig_dest */ 963 xasprintf(&prompt, "Enter PIN%sfor %s key %s: ", 964 (id->key->sk_flags & SSH_SK_USER_PRESENCE_REQD) ? 965 " and confirm user presence " : " ", 966 sshkey_type(id->key), fp); 967 pin = read_passphrase(prompt, RP_USE_ASKPASS); 968 retried = 1; 969 goto retry_pin; 970 } 971 error_fr(r, "sshkey_sign"); 972 goto send; 973 } 974 /* Success */ 975 ok = 0; 976 debug_f("good signature"); 977 send: 978 notify_complete(notifier, "User presence confirmed"); 979 980 if (ok == 0) { 981 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 || 982 (r = sshbuf_put_string(msg, signature, slen)) != 0) 983 fatal_fr(r, "compose"); 984 } else if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0) 985 fatal_fr(r, "compose failure"); 986 987 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 988 fatal_fr(r, "enqueue"); 989 990 sshbuf_free(sid); 991 sshbuf_free(data); 992 sshbuf_free(msg); 993 sshkey_free(key); 994 sshkey_free(hostkey); 995 free(fp); 996 free(signature); 997 free(sig_dest); 998 free(user); 999 free(prompt); 1000 if (pin != NULL) 1001 freezero(pin, strlen(pin)); 1002 } 1003 1004 /* shared */ 1005 static void 1006 process_remove_identity(SocketEntry *e) 1007 { 1008 int r, success = 0; 1009 struct sshkey *key = NULL; 1010 Identity *id; 1011 1012 debug2_f("entering"); 1013 if ((r = sshkey_froms(e->request, &key)) != 0) { 1014 error_fr(r, "parse key"); 1015 goto done; 1016 } 1017 if ((id = lookup_identity(key)) == NULL) { 1018 debug_f("key not found"); 1019 goto done; 1020 } 1021 /* identity not visible, cannot be removed */ 1022 if (identity_permitted(id, e, NULL, NULL, NULL) != 0) 1023 goto done; /* error already logged */ 1024 /* We have this key, free it. */ 1025 if (idtab->nentries < 1) 1026 fatal_f("internal error: nentries %d", idtab->nentries); 1027 TAILQ_REMOVE(&idtab->idlist, id, next); 1028 free_identity(id); 1029 idtab->nentries--; 1030 success = 1; 1031 done: 1032 sshkey_free(key); 1033 send_status(e, success); 1034 } 1035 1036 static void 1037 remove_all_identities(void) 1038 { 1039 Identity *id; 1040 1041 debug2_f("entering"); 1042 /* Loop over all identities and clear the keys. */ 1043 for (id = TAILQ_FIRST(&idtab->idlist); id; 1044 id = TAILQ_FIRST(&idtab->idlist)) { 1045 TAILQ_REMOVE(&idtab->idlist, id, next); 1046 free_identity(id); 1047 } 1048 1049 /* Mark that there are no identities. */ 1050 idtab->nentries = 0; 1051 } 1052 1053 static void 1054 process_remove_all_identities(SocketEntry *e) 1055 { 1056 remove_all_identities(); 1057 1058 /* Send success. */ 1059 send_status(e, 1); 1060 } 1061 1062 /* removes expired keys and returns number of seconds until the next expiry */ 1063 static time_t 1064 reaper(void) 1065 { 1066 time_t deadline = 0, now = monotime(); 1067 Identity *id, *nxt; 1068 1069 for (id = TAILQ_FIRST(&idtab->idlist); id; id = nxt) { 1070 nxt = TAILQ_NEXT(id, next); 1071 if (id->death == 0) 1072 continue; 1073 if (now >= id->death) { 1074 debug("expiring key '%s'", id->comment); 1075 TAILQ_REMOVE(&idtab->idlist, id, next); 1076 free_identity(id); 1077 idtab->nentries--; 1078 } else 1079 deadline = (deadline == 0) ? id->death : 1080 MINIMUM(deadline, id->death); 1081 } 1082 if (deadline == 0 || deadline <= now) 1083 return 0; 1084 else 1085 return (deadline - now); 1086 } 1087 1088 static int 1089 parse_dest_constraint_hop(struct sshbuf *b, struct dest_constraint_hop *dch) 1090 { 1091 u_char key_is_ca; 1092 size_t elen = 0; 1093 int r; 1094 struct sshkey *k = NULL; 1095 char *fp; 1096 1097 memset(dch, '\0', sizeof(*dch)); 1098 if ((r = sshbuf_get_cstring(b, &dch->user, NULL)) != 0 || 1099 (r = sshbuf_get_cstring(b, &dch->hostname, NULL)) != 0 || 1100 (r = sshbuf_get_string_direct(b, NULL, &elen)) != 0) { 1101 error_fr(r, "parse"); 1102 goto out; 1103 } 1104 if (elen != 0) { 1105 error_f("unsupported extensions (len %zu)", elen); 1106 r = SSH_ERR_FEATURE_UNSUPPORTED; 1107 goto out; 1108 } 1109 if (*dch->hostname == '\0') { 1110 free(dch->hostname); 1111 dch->hostname = NULL; 1112 } 1113 if (*dch->user == '\0') { 1114 free(dch->user); 1115 dch->user = NULL; 1116 } 1117 while (sshbuf_len(b) != 0) { 1118 dch->keys = xrecallocarray(dch->keys, dch->nkeys, 1119 dch->nkeys + 1, sizeof(*dch->keys)); 1120 dch->key_is_ca = xrecallocarray(dch->key_is_ca, dch->nkeys, 1121 dch->nkeys + 1, sizeof(*dch->key_is_ca)); 1122 if ((r = sshkey_froms(b, &k)) != 0 || 1123 (r = sshbuf_get_u8(b, &key_is_ca)) != 0) 1124 goto out; 1125 if ((fp = sshkey_fingerprint(k, SSH_FP_HASH_DEFAULT, 1126 SSH_FP_DEFAULT)) == NULL) 1127 fatal_f("fingerprint failed"); 1128 debug3_f("%s%s%s: adding %skey %s %s", 1129 dch->user == NULL ? "" : dch->user, 1130 dch->user == NULL ? "" : "@", 1131 dch->hostname, key_is_ca ? "CA " : "", sshkey_type(k), fp); 1132 free(fp); 1133 dch->keys[dch->nkeys] = k; 1134 dch->key_is_ca[dch->nkeys] = key_is_ca != 0; 1135 dch->nkeys++; 1136 k = NULL; /* transferred */ 1137 } 1138 /* success */ 1139 r = 0; 1140 out: 1141 sshkey_free(k); 1142 return r; 1143 } 1144 1145 static int 1146 parse_dest_constraint(struct sshbuf *m, struct dest_constraint *dc) 1147 { 1148 struct sshbuf *b = NULL, *frombuf = NULL, *tobuf = NULL; 1149 int r; 1150 size_t elen = 0; 1151 1152 debug3_f("entering"); 1153 1154 memset(dc, '\0', sizeof(*dc)); 1155 if ((r = sshbuf_froms(m, &b)) != 0 || 1156 (r = sshbuf_froms(b, &frombuf)) != 0 || 1157 (r = sshbuf_froms(b, &tobuf)) != 0 || 1158 (r = sshbuf_get_string_direct(b, NULL, &elen)) != 0) { 1159 error_fr(r, "parse"); 1160 goto out; 1161 } 1162 if ((r = parse_dest_constraint_hop(frombuf, &dc->from)) != 0 || 1163 (r = parse_dest_constraint_hop(tobuf, &dc->to)) != 0) 1164 goto out; /* already logged */ 1165 if (elen != 0) { 1166 error_f("unsupported extensions (len %zu)", elen); 1167 r = SSH_ERR_FEATURE_UNSUPPORTED; 1168 goto out; 1169 } 1170 debug2_f("parsed %s (%u keys) > %s%s%s (%u keys)", 1171 dc->from.hostname ? dc->from.hostname : "(ORIGIN)", dc->from.nkeys, 1172 dc->to.user ? dc->to.user : "", dc->to.user ? "@" : "", 1173 dc->to.hostname ? dc->to.hostname : "(ANY)", dc->to.nkeys); 1174 /* check consistency */ 1175 if ((dc->from.hostname == NULL) != (dc->from.nkeys == 0) || 1176 dc->from.user != NULL) { 1177 error_f("inconsistent \"from\" specification"); 1178 r = SSH_ERR_INVALID_FORMAT; 1179 goto out; 1180 } 1181 if (dc->to.hostname == NULL || dc->to.nkeys == 0) { 1182 error_f("incomplete \"to\" specification"); 1183 r = SSH_ERR_INVALID_FORMAT; 1184 goto out; 1185 } 1186 /* success */ 1187 r = 0; 1188 out: 1189 sshbuf_free(b); 1190 sshbuf_free(frombuf); 1191 sshbuf_free(tobuf); 1192 return r; 1193 } 1194 1195 static int 1196 parse_key_constraint_extension(struct sshbuf *m, char **sk_providerp, 1197 struct dest_constraint **dcsp, size_t *ndcsp, int *cert_onlyp, 1198 struct sshkey ***certs, size_t *ncerts) 1199 { 1200 char *ext_name = NULL; 1201 int r; 1202 struct sshbuf *b = NULL; 1203 u_char v; 1204 struct sshkey *k; 1205 1206 if ((r = sshbuf_get_cstring(m, &ext_name, NULL)) != 0) { 1207 error_fr(r, "parse constraint extension"); 1208 goto out; 1209 } 1210 debug_f("constraint ext %s", ext_name); 1211 if (strcmp(ext_name, "sk-provider@openssh.com") == 0) { 1212 if (sk_providerp == NULL) { 1213 error_f("%s not valid here", ext_name); 1214 r = SSH_ERR_INVALID_FORMAT; 1215 goto out; 1216 } 1217 if (*sk_providerp != NULL) { 1218 error_f("%s already set", ext_name); 1219 r = SSH_ERR_INVALID_FORMAT; 1220 goto out; 1221 } 1222 if ((r = sshbuf_get_cstring(m, sk_providerp, NULL)) != 0) { 1223 error_fr(r, "parse %s", ext_name); 1224 goto out; 1225 } 1226 } else if (strcmp(ext_name, 1227 "restrict-destination-v00@openssh.com") == 0) { 1228 if (*dcsp != NULL) { 1229 error_f("%s already set", ext_name); 1230 r = SSH_ERR_INVALID_FORMAT; 1231 goto out; 1232 } 1233 if ((r = sshbuf_froms(m, &b)) != 0) { 1234 error_fr(r, "parse %s outer", ext_name); 1235 goto out; 1236 } 1237 while (sshbuf_len(b) != 0) { 1238 if (*ndcsp >= AGENT_MAX_DEST_CONSTRAINTS) { 1239 error_f("too many %s constraints", ext_name); 1240 r = SSH_ERR_INVALID_FORMAT; 1241 goto out; 1242 } 1243 *dcsp = xrecallocarray(*dcsp, *ndcsp, *ndcsp + 1, 1244 sizeof(**dcsp)); 1245 if ((r = parse_dest_constraint(b, 1246 *dcsp + (*ndcsp)++)) != 0) 1247 goto out; /* error already logged */ 1248 } 1249 } else if (strcmp(ext_name, 1250 "associated-certs-v00@openssh.com") == 0) { 1251 if (certs == NULL || ncerts == NULL || cert_onlyp == NULL) { 1252 error_f("%s not valid here", ext_name); 1253 r = SSH_ERR_INVALID_FORMAT; 1254 goto out; 1255 } 1256 if (*certs != NULL) { 1257 error_f("%s already set", ext_name); 1258 r = SSH_ERR_INVALID_FORMAT; 1259 goto out; 1260 } 1261 if ((r = sshbuf_get_u8(m, &v)) != 0 || 1262 (r = sshbuf_froms(m, &b)) != 0) { 1263 error_fr(r, "parse %s", ext_name); 1264 goto out; 1265 } 1266 *cert_onlyp = v != 0; 1267 while (sshbuf_len(b) != 0) { 1268 if (*ncerts >= AGENT_MAX_EXT_CERTS) { 1269 error_f("too many %s constraints", ext_name); 1270 r = SSH_ERR_INVALID_FORMAT; 1271 goto out; 1272 } 1273 *certs = xrecallocarray(*certs, *ncerts, *ncerts + 1, 1274 sizeof(**certs)); 1275 if ((r = sshkey_froms(b, &k)) != 0) { 1276 error_fr(r, "parse key"); 1277 goto out; 1278 } 1279 (*certs)[(*ncerts)++] = k; 1280 } 1281 } else { 1282 error_f("unsupported constraint \"%s\"", ext_name); 1283 r = SSH_ERR_FEATURE_UNSUPPORTED; 1284 goto out; 1285 } 1286 /* success */ 1287 r = 0; 1288 out: 1289 free(ext_name); 1290 sshbuf_free(b); 1291 return r; 1292 } 1293 1294 static int 1295 parse_key_constraints(struct sshbuf *m, struct sshkey *k, time_t *deathp, 1296 u_int *secondsp, int *confirmp, char **sk_providerp, 1297 struct dest_constraint **dcsp, size_t *ndcsp, 1298 int *cert_onlyp, size_t *ncerts, struct sshkey ***certs) 1299 { 1300 u_char ctype; 1301 int r; 1302 u_int seconds; 1303 1304 while (sshbuf_len(m)) { 1305 if ((r = sshbuf_get_u8(m, &ctype)) != 0) { 1306 error_fr(r, "parse constraint type"); 1307 goto out; 1308 } 1309 switch (ctype) { 1310 case SSH_AGENT_CONSTRAIN_LIFETIME: 1311 if (*deathp != 0) { 1312 error_f("lifetime already set"); 1313 r = SSH_ERR_INVALID_FORMAT; 1314 goto out; 1315 } 1316 if ((r = sshbuf_get_u32(m, &seconds)) != 0) { 1317 error_fr(r, "parse lifetime constraint"); 1318 goto out; 1319 } 1320 *deathp = monotime() + seconds; 1321 *secondsp = seconds; 1322 break; 1323 case SSH_AGENT_CONSTRAIN_CONFIRM: 1324 if (*confirmp != 0) { 1325 error_f("confirm already set"); 1326 r = SSH_ERR_INVALID_FORMAT; 1327 goto out; 1328 } 1329 *confirmp = 1; 1330 break; 1331 case SSH_AGENT_CONSTRAIN_EXTENSION: 1332 if ((r = parse_key_constraint_extension(m, 1333 sk_providerp, dcsp, ndcsp, 1334 cert_onlyp, certs, ncerts)) != 0) 1335 goto out; /* error already logged */ 1336 break; 1337 default: 1338 error_f("Unknown constraint %d", ctype); 1339 r = SSH_ERR_FEATURE_UNSUPPORTED; 1340 goto out; 1341 } 1342 } 1343 /* success */ 1344 r = 0; 1345 out: 1346 return r; 1347 } 1348 1349 static void 1350 process_add_identity(SocketEntry *e) 1351 { 1352 Identity *id; 1353 int success = 0, confirm = 0; 1354 char *fp, *comment = NULL, *sk_provider = NULL; 1355 char canonical_provider[PATH_MAX]; 1356 time_t death = 0; 1357 u_int seconds = 0; 1358 struct dest_constraint *dest_constraints = NULL; 1359 size_t ndest_constraints = 0; 1360 struct sshkey *k = NULL; 1361 int r = SSH_ERR_INTERNAL_ERROR; 1362 1363 debug2_f("entering"); 1364 if ((r = sshkey_private_deserialize(e->request, &k)) != 0 || 1365 k == NULL || 1366 (r = sshbuf_get_cstring(e->request, &comment, NULL)) != 0) { 1367 error_fr(r, "parse"); 1368 goto out; 1369 } 1370 if (parse_key_constraints(e->request, k, &death, &seconds, &confirm, 1371 &sk_provider, &dest_constraints, &ndest_constraints, 1372 NULL, NULL, NULL) != 0) { 1373 error_f("failed to parse constraints"); 1374 sshbuf_reset(e->request); 1375 goto out; 1376 } 1377 dump_dest_constraints(__func__, dest_constraints, ndest_constraints); 1378 1379 if (sk_provider != NULL) { 1380 if (!sshkey_is_sk(k)) { 1381 error("Cannot add provider: %s is not an " 1382 "authenticator-hosted key", sshkey_type(k)); 1383 goto out; 1384 } 1385 if (strcasecmp(sk_provider, "internal") == 0) { 1386 debug_f("internal provider"); 1387 } else { 1388 if (socket_is_remote(e) && !remote_add_provider) { 1389 verbose("failed add of SK provider \"%.100s\": " 1390 "remote addition of providers is disabled", 1391 sk_provider); 1392 goto out; 1393 } 1394 if (realpath(sk_provider, canonical_provider) == NULL) { 1395 verbose("failed provider \"%.100s\": " 1396 "realpath: %s", sk_provider, 1397 strerror(errno)); 1398 goto out; 1399 } 1400 free(sk_provider); 1401 sk_provider = xstrdup(canonical_provider); 1402 if (match_pattern_list(sk_provider, 1403 allowed_providers, 0) != 1) { 1404 error("Refusing add key: " 1405 "provider %s not allowed", sk_provider); 1406 goto out; 1407 } 1408 } 1409 } 1410 if ((r = sshkey_shield_private(k)) != 0) { 1411 error_fr(r, "shield private"); 1412 goto out; 1413 } 1414 if (lifetime && !death) 1415 death = monotime() + lifetime; 1416 if ((id = lookup_identity(k)) == NULL) { 1417 id = xcalloc(1, sizeof(Identity)); 1418 TAILQ_INSERT_TAIL(&idtab->idlist, id, next); 1419 /* Increment the number of identities. */ 1420 idtab->nentries++; 1421 } else { 1422 /* identity not visible, do not update */ 1423 if (identity_permitted(id, e, NULL, NULL, NULL) != 0) 1424 goto out; /* error already logged */ 1425 /* key state might have been updated */ 1426 sshkey_free(id->key); 1427 free(id->comment); 1428 free(id->sk_provider); 1429 free_dest_constraints(id->dest_constraints, 1430 id->ndest_constraints); 1431 } 1432 /* success */ 1433 id->key = k; 1434 id->comment = comment; 1435 id->death = death; 1436 id->confirm = confirm; 1437 id->sk_provider = sk_provider; 1438 id->dest_constraints = dest_constraints; 1439 id->ndest_constraints = ndest_constraints; 1440 1441 if ((fp = sshkey_fingerprint(k, SSH_FP_HASH_DEFAULT, 1442 SSH_FP_DEFAULT)) == NULL) 1443 fatal_f("sshkey_fingerprint failed"); 1444 debug_f("add %s %s \"%.100s\" (life: %u) (confirm: %u) " 1445 "(provider: %s) (destination constraints: %zu)", 1446 sshkey_ssh_name(k), fp, comment, seconds, confirm, 1447 sk_provider == NULL ? "none" : sk_provider, ndest_constraints); 1448 free(fp); 1449 /* transferred */ 1450 k = NULL; 1451 comment = NULL; 1452 sk_provider = NULL; 1453 dest_constraints = NULL; 1454 ndest_constraints = 0; 1455 success = 1; 1456 out: 1457 free(sk_provider); 1458 free(comment); 1459 sshkey_free(k); 1460 free_dest_constraints(dest_constraints, ndest_constraints); 1461 send_status(e, success); 1462 } 1463 1464 /* XXX todo: encrypt sensitive data with passphrase */ 1465 static void 1466 process_lock_agent(SocketEntry *e, int lock) 1467 { 1468 int r, success = 0, delay; 1469 char *passwd; 1470 u_char passwdhash[LOCK_SIZE]; 1471 static u_int fail_count = 0; 1472 size_t pwlen; 1473 1474 debug2_f("entering"); 1475 /* 1476 * This is deliberately fatal: the user has requested that we lock, 1477 * but we can't parse their request properly. The only safe thing to 1478 * do is abort. 1479 */ 1480 if ((r = sshbuf_get_cstring(e->request, &passwd, &pwlen)) != 0) 1481 fatal_fr(r, "parse"); 1482 if (pwlen == 0) { 1483 debug("empty password not supported"); 1484 } else if (locked && !lock) { 1485 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 1486 passwdhash, sizeof(passwdhash), LOCK_ROUNDS) < 0) 1487 fatal("bcrypt_pbkdf"); 1488 if (timingsafe_bcmp(passwdhash, lock_pwhash, LOCK_SIZE) == 0) { 1489 debug("agent unlocked"); 1490 locked = 0; 1491 fail_count = 0; 1492 explicit_bzero(lock_pwhash, sizeof(lock_pwhash)); 1493 success = 1; 1494 } else { 1495 /* delay in 0.1s increments up to 10s */ 1496 if (fail_count < 100) 1497 fail_count++; 1498 delay = 100000 * fail_count; 1499 debug("unlock failed, delaying %0.1lf seconds", 1500 (double)delay/1000000); 1501 usleep(delay); 1502 } 1503 explicit_bzero(passwdhash, sizeof(passwdhash)); 1504 } else if (!locked && lock) { 1505 debug("agent locked"); 1506 locked = 1; 1507 arc4random_buf(lock_salt, sizeof(lock_salt)); 1508 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 1509 lock_pwhash, sizeof(lock_pwhash), LOCK_ROUNDS) < 0) 1510 fatal("bcrypt_pbkdf"); 1511 success = 1; 1512 } 1513 freezero(passwd, pwlen); 1514 send_status(e, success); 1515 } 1516 1517 static void 1518 no_identities(SocketEntry *e) 1519 { 1520 struct sshbuf *msg; 1521 int r; 1522 1523 if ((msg = sshbuf_new()) == NULL) 1524 fatal_f("sshbuf_new failed"); 1525 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 1526 (r = sshbuf_put_u32(msg, 0)) != 0 || 1527 (r = sshbuf_put_stringb(e->output, msg)) != 0) 1528 fatal_fr(r, "compose"); 1529 sshbuf_free(msg); 1530 } 1531 1532 #ifdef ENABLE_PKCS11 1533 /* Add an identity to idlist; takes ownership of 'key' and 'comment' */ 1534 static void 1535 add_p11_identity(struct sshkey *key, char *comment, const char *provider, 1536 time_t death, u_int confirm, struct dest_constraint *dest_constraints, 1537 size_t ndest_constraints) 1538 { 1539 Identity *id; 1540 1541 if (lookup_identity(key) != NULL) { 1542 sshkey_free(key); 1543 free(comment); 1544 return; 1545 } 1546 id = xcalloc(1, sizeof(Identity)); 1547 id->key = key; 1548 id->comment = comment; 1549 id->provider = xstrdup(provider); 1550 id->death = death; 1551 id->confirm = confirm; 1552 id->dest_constraints = dup_dest_constraints(dest_constraints, 1553 ndest_constraints); 1554 id->ndest_constraints = ndest_constraints; 1555 TAILQ_INSERT_TAIL(&idtab->idlist, id, next); 1556 idtab->nentries++; 1557 } 1558 1559 static void 1560 process_add_smartcard_key(SocketEntry *e) 1561 { 1562 char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX]; 1563 char **comments = NULL; 1564 int r, i, count = 0, success = 0, confirm = 0; 1565 u_int seconds = 0; 1566 time_t death = 0; 1567 struct sshkey **keys = NULL, *k; 1568 struct dest_constraint *dest_constraints = NULL; 1569 size_t j, ndest_constraints = 0, ncerts = 0; 1570 struct sshkey **certs = NULL; 1571 int cert_only = 0; 1572 1573 debug2_f("entering"); 1574 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 1575 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) { 1576 error_fr(r, "parse"); 1577 goto send; 1578 } 1579 if (parse_key_constraints(e->request, NULL, &death, &seconds, &confirm, 1580 NULL, &dest_constraints, &ndest_constraints, &cert_only, 1581 &ncerts, &certs) != 0) { 1582 error_f("failed to parse constraints"); 1583 goto send; 1584 } 1585 dump_dest_constraints(__func__, dest_constraints, ndest_constraints); 1586 if (socket_is_remote(e) && !remote_add_provider) { 1587 verbose("failed PKCS#11 add of \"%.100s\": remote addition of " 1588 "providers is disabled", provider); 1589 goto send; 1590 } 1591 if (realpath(provider, canonical_provider) == NULL) { 1592 verbose("failed PKCS#11 add of \"%.100s\": realpath: %s", 1593 provider, strerror(errno)); 1594 goto send; 1595 } 1596 if (match_pattern_list(canonical_provider, allowed_providers, 0) != 1) { 1597 verbose("refusing PKCS#11 add of \"%.100s\": " 1598 "provider not allowed", canonical_provider); 1599 goto send; 1600 } 1601 debug_f("add %.100s", canonical_provider); 1602 if (lifetime && !death) 1603 death = monotime() + lifetime; 1604 1605 count = pkcs11_add_provider(canonical_provider, pin, &keys, &comments); 1606 for (i = 0; i < count; i++) { 1607 if (comments[i] == NULL || comments[i][0] == '\0') { 1608 free(comments[i]); 1609 comments[i] = xstrdup(canonical_provider); 1610 } 1611 for (j = 0; j < ncerts; j++) { 1612 if (!sshkey_is_cert(certs[j])) 1613 continue; 1614 if (!sshkey_equal_public(keys[i], certs[j])) 1615 continue; 1616 if (pkcs11_make_cert(keys[i], certs[j], &k) != 0) 1617 continue; 1618 add_p11_identity(k, xstrdup(comments[i]), 1619 canonical_provider, death, confirm, 1620 dest_constraints, ndest_constraints); 1621 success = 1; 1622 } 1623 if (!cert_only && lookup_identity(keys[i]) == NULL) { 1624 add_p11_identity(keys[i], comments[i], 1625 canonical_provider, death, confirm, 1626 dest_constraints, ndest_constraints); 1627 keys[i] = NULL; /* transferred */ 1628 comments[i] = NULL; /* transferred */ 1629 success = 1; 1630 } 1631 /* XXX update constraints for existing keys */ 1632 sshkey_free(keys[i]); 1633 free(comments[i]); 1634 } 1635 send: 1636 free(pin); 1637 free(provider); 1638 free(keys); 1639 free(comments); 1640 free_dest_constraints(dest_constraints, ndest_constraints); 1641 for (j = 0; j < ncerts; j++) 1642 sshkey_free(certs[j]); 1643 free(certs); 1644 send_status(e, success); 1645 } 1646 1647 static void 1648 process_remove_smartcard_key(SocketEntry *e) 1649 { 1650 char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX]; 1651 int r, success = 0; 1652 Identity *id, *nxt; 1653 1654 debug2_f("entering"); 1655 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 1656 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) { 1657 error_fr(r, "parse"); 1658 goto send; 1659 } 1660 free(pin); 1661 1662 if (realpath(provider, canonical_provider) == NULL) { 1663 verbose("failed PKCS#11 add of \"%.100s\": realpath: %s", 1664 provider, strerror(errno)); 1665 goto send; 1666 } 1667 1668 debug_f("remove %.100s", canonical_provider); 1669 for (id = TAILQ_FIRST(&idtab->idlist); id; id = nxt) { 1670 nxt = TAILQ_NEXT(id, next); 1671 /* Skip file--based keys */ 1672 if (id->provider == NULL) 1673 continue; 1674 if (!strcmp(canonical_provider, id->provider)) { 1675 TAILQ_REMOVE(&idtab->idlist, id, next); 1676 free_identity(id); 1677 idtab->nentries--; 1678 } 1679 } 1680 if (pkcs11_del_provider(canonical_provider) == 0) 1681 success = 1; 1682 else 1683 error_f("pkcs11_del_provider failed"); 1684 send: 1685 free(provider); 1686 send_status(e, success); 1687 } 1688 #endif /* ENABLE_PKCS11 */ 1689 1690 static int 1691 process_ext_session_bind(SocketEntry *e) 1692 { 1693 int r, sid_match, key_match; 1694 struct sshkey *key = NULL; 1695 struct sshbuf *sid = NULL, *sig = NULL; 1696 char *fp = NULL; 1697 size_t i; 1698 u_char fwd = 0; 1699 1700 debug2_f("entering"); 1701 e->session_bind_attempted = 1; 1702 if ((r = sshkey_froms(e->request, &key)) != 0 || 1703 (r = sshbuf_froms(e->request, &sid)) != 0 || 1704 (r = sshbuf_froms(e->request, &sig)) != 0 || 1705 (r = sshbuf_get_u8(e->request, &fwd)) != 0) { 1706 error_fr(r, "parse"); 1707 goto out; 1708 } 1709 if (sshbuf_len(sid) > AGENT_MAX_SID_LEN) { 1710 error_f("session ID too long"); 1711 goto out; 1712 } 1713 if ((fp = sshkey_fingerprint(key, SSH_FP_HASH_DEFAULT, 1714 SSH_FP_DEFAULT)) == NULL) 1715 fatal_f("fingerprint failed"); 1716 /* check signature with hostkey on session ID */ 1717 if ((r = sshkey_verify(key, sshbuf_ptr(sig), sshbuf_len(sig), 1718 sshbuf_ptr(sid), sshbuf_len(sid), NULL, 0, NULL)) != 0) { 1719 error_fr(r, "sshkey_verify for %s %s", sshkey_type(key), fp); 1720 goto out; 1721 } 1722 /* check whether sid/key already recorded */ 1723 for (i = 0; i < e->nsession_ids; i++) { 1724 if (!e->session_ids[i].forwarded) { 1725 error_f("attempt to bind session ID to socket " 1726 "previously bound for authentication attempt"); 1727 r = -1; 1728 goto out; 1729 } 1730 sid_match = buf_equal(sid, e->session_ids[i].sid) == 0; 1731 key_match = sshkey_equal(key, e->session_ids[i].key); 1732 if (sid_match && key_match) { 1733 debug_f("session ID already recorded for %s %s", 1734 sshkey_type(key), fp); 1735 r = 0; 1736 goto out; 1737 } else if (sid_match) { 1738 error_f("session ID recorded against different key " 1739 "for %s %s", sshkey_type(key), fp); 1740 r = -1; 1741 goto out; 1742 } 1743 /* 1744 * new sid with previously-seen key can happen, e.g. multiple 1745 * connections to the same host. 1746 */ 1747 } 1748 /* record new key/sid */ 1749 if (e->nsession_ids >= AGENT_MAX_SESSION_IDS) { 1750 error_f("too many session IDs recorded"); 1751 r = -1; 1752 goto out; 1753 } 1754 e->session_ids = xrecallocarray(e->session_ids, e->nsession_ids, 1755 e->nsession_ids + 1, sizeof(*e->session_ids)); 1756 i = e->nsession_ids++; 1757 debug_f("recorded %s %s (slot %zu of %d)", sshkey_type(key), fp, i, 1758 AGENT_MAX_SESSION_IDS); 1759 e->session_ids[i].key = key; 1760 e->session_ids[i].forwarded = fwd != 0; 1761 key = NULL; /* transferred */ 1762 /* can't transfer sid; it's refcounted and scoped to request's life */ 1763 if ((e->session_ids[i].sid = sshbuf_new()) == NULL) 1764 fatal_f("sshbuf_new"); 1765 if ((r = sshbuf_putb(e->session_ids[i].sid, sid)) != 0) 1766 fatal_fr(r, "sshbuf_putb session ID"); 1767 /* success */ 1768 r = 0; 1769 out: 1770 free(fp); 1771 sshkey_free(key); 1772 sshbuf_free(sid); 1773 sshbuf_free(sig); 1774 return r == 0 ? 1 : 0; 1775 } 1776 1777 static void 1778 process_extension(SocketEntry *e) 1779 { 1780 int r, success = 0; 1781 char *name; 1782 1783 debug2_f("entering"); 1784 if ((r = sshbuf_get_cstring(e->request, &name, NULL)) != 0) { 1785 error_fr(r, "parse"); 1786 goto send; 1787 } 1788 if (strcmp(name, "session-bind@openssh.com") == 0) 1789 success = process_ext_session_bind(e); 1790 else 1791 debug_f("unsupported extension \"%s\"", name); 1792 free(name); 1793 send: 1794 send_status(e, success); 1795 } 1796 /* 1797 * dispatch incoming message. 1798 * returns 1 on success, 0 for incomplete messages or -1 on error. 1799 */ 1800 static int 1801 process_message(u_int socknum) 1802 { 1803 u_int msg_len; 1804 u_char type; 1805 const u_char *cp; 1806 int r; 1807 SocketEntry *e; 1808 1809 if (socknum >= sockets_alloc) 1810 fatal_f("sock %u >= allocated %u", socknum, sockets_alloc); 1811 e = &sockets[socknum]; 1812 1813 if (sshbuf_len(e->input) < 5) 1814 return 0; /* Incomplete message header. */ 1815 cp = sshbuf_ptr(e->input); 1816 msg_len = PEEK_U32(cp); 1817 if (msg_len > AGENT_MAX_LEN) { 1818 debug_f("socket %u (fd=%d) message too long %u > %u", 1819 socknum, e->fd, msg_len, AGENT_MAX_LEN); 1820 return -1; 1821 } 1822 if (sshbuf_len(e->input) < msg_len + 4) 1823 return 0; /* Incomplete message body. */ 1824 1825 /* move the current input to e->request */ 1826 sshbuf_reset(e->request); 1827 if ((r = sshbuf_get_stringb(e->input, e->request)) != 0 || 1828 (r = sshbuf_get_u8(e->request, &type)) != 0) { 1829 if (r == SSH_ERR_MESSAGE_INCOMPLETE || 1830 r == SSH_ERR_STRING_TOO_LARGE) { 1831 error_fr(r, "parse"); 1832 return -1; 1833 } 1834 fatal_fr(r, "parse"); 1835 } 1836 1837 debug_f("socket %u (fd=%d) type %d", socknum, e->fd, type); 1838 1839 /* check whether agent is locked */ 1840 if (locked && type != SSH_AGENTC_UNLOCK) { 1841 sshbuf_reset(e->request); 1842 switch (type) { 1843 case SSH2_AGENTC_REQUEST_IDENTITIES: 1844 /* send empty lists */ 1845 no_identities(e); 1846 break; 1847 default: 1848 /* send a fail message for all other request types */ 1849 send_status(e, 0); 1850 } 1851 return 1; 1852 } 1853 1854 switch (type) { 1855 case SSH_AGENTC_LOCK: 1856 case SSH_AGENTC_UNLOCK: 1857 process_lock_agent(e, type == SSH_AGENTC_LOCK); 1858 break; 1859 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 1860 process_remove_all_identities(e); /* safe for !WITH_SSH1 */ 1861 break; 1862 /* ssh2 */ 1863 case SSH2_AGENTC_SIGN_REQUEST: 1864 process_sign_request2(e); 1865 break; 1866 case SSH2_AGENTC_REQUEST_IDENTITIES: 1867 process_request_identities(e); 1868 break; 1869 case SSH2_AGENTC_ADD_IDENTITY: 1870 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 1871 process_add_identity(e); 1872 break; 1873 case SSH2_AGENTC_REMOVE_IDENTITY: 1874 process_remove_identity(e); 1875 break; 1876 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 1877 process_remove_all_identities(e); 1878 break; 1879 #ifdef ENABLE_PKCS11 1880 case SSH_AGENTC_ADD_SMARTCARD_KEY: 1881 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 1882 process_add_smartcard_key(e); 1883 break; 1884 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 1885 process_remove_smartcard_key(e); 1886 break; 1887 #endif /* ENABLE_PKCS11 */ 1888 case SSH_AGENTC_EXTENSION: 1889 process_extension(e); 1890 break; 1891 default: 1892 /* Unknown message. Respond with failure. */ 1893 error("Unknown message %d", type); 1894 sshbuf_reset(e->request); 1895 send_status(e, 0); 1896 break; 1897 } 1898 return 1; 1899 } 1900 1901 static void 1902 new_socket(sock_type type, int fd) 1903 { 1904 u_int i, old_alloc, new_alloc; 1905 1906 debug_f("type = %s", type == AUTH_CONNECTION ? "CONNECTION" : 1907 (type == AUTH_SOCKET ? "SOCKET" : "UNKNOWN")); 1908 if (type == AUTH_CONNECTION) { 1909 debug("xcount %d -> %d", xcount, xcount + 1); 1910 ++xcount; 1911 } 1912 set_nonblock(fd); 1913 1914 if (fd > max_fd) 1915 max_fd = fd; 1916 1917 for (i = 0; i < sockets_alloc; i++) 1918 if (sockets[i].type == AUTH_UNUSED) { 1919 sockets[i].fd = fd; 1920 if ((sockets[i].input = sshbuf_new()) == NULL || 1921 (sockets[i].output = sshbuf_new()) == NULL || 1922 (sockets[i].request = sshbuf_new()) == NULL) 1923 fatal_f("sshbuf_new failed"); 1924 sockets[i].type = type; 1925 return; 1926 } 1927 old_alloc = sockets_alloc; 1928 new_alloc = sockets_alloc + 10; 1929 sockets = xrecallocarray(sockets, old_alloc, new_alloc, 1930 sizeof(sockets[0])); 1931 for (i = old_alloc; i < new_alloc; i++) 1932 sockets[i].type = AUTH_UNUSED; 1933 sockets_alloc = new_alloc; 1934 sockets[old_alloc].fd = fd; 1935 if ((sockets[old_alloc].input = sshbuf_new()) == NULL || 1936 (sockets[old_alloc].output = sshbuf_new()) == NULL || 1937 (sockets[old_alloc].request = sshbuf_new()) == NULL) 1938 fatal_f("sshbuf_new failed"); 1939 sockets[old_alloc].type = type; 1940 } 1941 1942 static int 1943 handle_socket_read(u_int socknum) 1944 { 1945 struct sockaddr_un sunaddr; 1946 socklen_t slen; 1947 uid_t euid; 1948 gid_t egid; 1949 int fd; 1950 1951 slen = sizeof(sunaddr); 1952 fd = accept(sockets[socknum].fd, (struct sockaddr *)&sunaddr, &slen); 1953 if (fd == -1) { 1954 error("accept from AUTH_SOCKET: %s", strerror(errno)); 1955 return -1; 1956 } 1957 if (getpeereid(fd, &euid, &egid) == -1) { 1958 error("getpeereid %d failed: %s", fd, strerror(errno)); 1959 close(fd); 1960 return -1; 1961 } 1962 if ((euid != 0) && (getuid() != euid)) { 1963 error("uid mismatch: peer euid %u != uid %u", 1964 (u_int) euid, (u_int) getuid()); 1965 close(fd); 1966 return -1; 1967 } 1968 new_socket(AUTH_CONNECTION, fd); 1969 return 0; 1970 } 1971 1972 static int 1973 handle_conn_read(u_int socknum) 1974 { 1975 char buf[AGENT_RBUF_LEN]; 1976 ssize_t len; 1977 int r; 1978 1979 if ((len = read(sockets[socknum].fd, buf, sizeof(buf))) <= 0) { 1980 if (len == -1) { 1981 if (errno == EAGAIN || errno == EINTR) 1982 return 0; 1983 error_f("read error on socket %u (fd %d): %s", 1984 socknum, sockets[socknum].fd, strerror(errno)); 1985 } 1986 return -1; 1987 } 1988 if ((r = sshbuf_put(sockets[socknum].input, buf, len)) != 0) 1989 fatal_fr(r, "compose"); 1990 explicit_bzero(buf, sizeof(buf)); 1991 for (;;) { 1992 if ((r = process_message(socknum)) == -1) 1993 return -1; 1994 else if (r == 0) 1995 break; 1996 } 1997 return 0; 1998 } 1999 2000 static int 2001 handle_conn_write(u_int socknum) 2002 { 2003 ssize_t len; 2004 int r; 2005 2006 if (sshbuf_len(sockets[socknum].output) == 0) 2007 return 0; /* shouldn't happen */ 2008 if ((len = write(sockets[socknum].fd, 2009 sshbuf_ptr(sockets[socknum].output), 2010 sshbuf_len(sockets[socknum].output))) <= 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_consume(sockets[socknum].output, len)) != 0) 2020 fatal_fr(r, "consume"); 2021 return 0; 2022 } 2023 2024 static void 2025 after_poll(struct pollfd *pfd, size_t npfd, u_int maxfds) 2026 { 2027 size_t i; 2028 u_int socknum, activefds = npfd; 2029 2030 for (i = 0; i < npfd; i++) { 2031 if (pfd[i].revents == 0) 2032 continue; 2033 /* Find sockets entry */ 2034 for (socknum = 0; socknum < sockets_alloc; socknum++) { 2035 if (sockets[socknum].type != AUTH_SOCKET && 2036 sockets[socknum].type != AUTH_CONNECTION) 2037 continue; 2038 if (pfd[i].fd == sockets[socknum].fd) 2039 break; 2040 } 2041 if (socknum >= sockets_alloc) { 2042 error_f("no socket for fd %d", pfd[i].fd); 2043 continue; 2044 } 2045 /* Process events */ 2046 switch (sockets[socknum].type) { 2047 case AUTH_SOCKET: 2048 if ((pfd[i].revents & (POLLIN|POLLERR)) == 0) 2049 break; 2050 if (npfd > maxfds) { 2051 debug3("out of fds (active %u >= limit %u); " 2052 "skipping accept", activefds, maxfds); 2053 break; 2054 } 2055 if (handle_socket_read(socknum) == 0) 2056 activefds++; 2057 break; 2058 case AUTH_CONNECTION: 2059 if ((pfd[i].revents & (POLLIN|POLLHUP|POLLERR)) != 0 && 2060 handle_conn_read(socknum) != 0) 2061 goto close_sock; 2062 if ((pfd[i].revents & (POLLOUT|POLLHUP)) != 0 && 2063 handle_conn_write(socknum) != 0) { 2064 close_sock: 2065 if (activefds == 0) 2066 fatal("activefds == 0 at close_sock"); 2067 close_socket(&sockets[socknum]); 2068 activefds--; 2069 break; 2070 } 2071 break; 2072 default: 2073 break; 2074 } 2075 } 2076 } 2077 2078 static int 2079 prepare_poll(struct pollfd **pfdp, size_t *npfdp, struct timespec *timeoutp, u_int maxfds) 2080 { 2081 struct pollfd *pfd = *pfdp; 2082 size_t i, j, npfd = 0; 2083 time_t deadline; 2084 int r; 2085 2086 /* Count active sockets */ 2087 for (i = 0; i < sockets_alloc; i++) { 2088 switch (sockets[i].type) { 2089 case AUTH_SOCKET: 2090 case AUTH_CONNECTION: 2091 npfd++; 2092 break; 2093 case AUTH_UNUSED: 2094 break; 2095 default: 2096 fatal("Unknown socket type %d", sockets[i].type); 2097 break; 2098 } 2099 } 2100 if (npfd != *npfdp && 2101 (pfd = recallocarray(pfd, *npfdp, npfd, sizeof(*pfd))) == NULL) 2102 fatal_f("recallocarray failed"); 2103 *pfdp = pfd; 2104 *npfdp = npfd; 2105 2106 for (i = j = 0; i < sockets_alloc; i++) { 2107 switch (sockets[i].type) { 2108 case AUTH_SOCKET: 2109 if (npfd > maxfds) { 2110 debug3("out of fds (active %zu >= limit %u); " 2111 "skipping arming listener", npfd, maxfds); 2112 break; 2113 } 2114 pfd[j].fd = sockets[i].fd; 2115 pfd[j].revents = 0; 2116 pfd[j].events = POLLIN; 2117 j++; 2118 break; 2119 case AUTH_CONNECTION: 2120 pfd[j].fd = sockets[i].fd; 2121 pfd[j].revents = 0; 2122 /* 2123 * Only prepare to read if we can handle a full-size 2124 * input read buffer and enqueue a max size reply.. 2125 */ 2126 if ((r = sshbuf_check_reserve(sockets[i].input, 2127 AGENT_RBUF_LEN)) == 0 && 2128 (r = sshbuf_check_reserve(sockets[i].output, 2129 AGENT_MAX_LEN)) == 0) 2130 pfd[j].events = POLLIN; 2131 else if (r != SSH_ERR_NO_BUFFER_SPACE) 2132 fatal_fr(r, "reserve"); 2133 if (sshbuf_len(sockets[i].output) > 0) 2134 pfd[j].events |= POLLOUT; 2135 j++; 2136 break; 2137 default: 2138 break; 2139 } 2140 } 2141 deadline = reaper(); 2142 if (parent_alive_interval != 0) 2143 deadline = (deadline == 0) ? parent_alive_interval : 2144 MINIMUM(deadline, parent_alive_interval); 2145 if (deadline != 0) 2146 ptimeout_deadline_sec(timeoutp, deadline); 2147 return (1); 2148 } 2149 2150 static void 2151 cleanup_socket(void) 2152 { 2153 if (cleanup_pid != 0 && getpid() != cleanup_pid) 2154 return; 2155 debug_f("cleanup"); 2156 if (socket_name[0]) 2157 unlink(socket_name); 2158 if (socket_dir[0]) 2159 rmdir(socket_dir); 2160 } 2161 2162 void 2163 cleanup_exit(int i) 2164 { 2165 cleanup_socket(); 2166 #ifdef ENABLE_PKCS11 2167 pkcs11_terminate(); 2168 #endif 2169 _exit(i); 2170 } 2171 2172 static void 2173 cleanup_handler(int sig) 2174 { 2175 signalled_exit = sig; 2176 } 2177 2178 static void 2179 keydrop_handler(int sig) 2180 { 2181 signalled_keydrop = sig; 2182 } 2183 2184 static void 2185 check_parent_exists(void) 2186 { 2187 /* 2188 * If our parent has exited then getppid() will return (pid_t)1, 2189 * so testing for that should be safe. 2190 */ 2191 if (parent_pid != -1 && getppid() != parent_pid) { 2192 /* printf("Parent has died - Authentication agent exiting.\n"); */ 2193 cleanup_socket(); 2194 _exit(2); 2195 } 2196 } 2197 2198 static void 2199 usage(void) 2200 { 2201 fprintf(stderr, 2202 "usage: ssh-agent [-c | -s] [-DdTUx] [-a bind_address] [-E fingerprint_hash]\n" 2203 " [-O option] [-P allowed_providers] [-t life]\n" 2204 " ssh-agent [-TU] [-a bind_address] [-E fingerprint_hash] [-O option]\n" 2205 " [-P allowed_providers] [-t life] command [arg ...]\n" 2206 " ssh-agent [-c | -s] -k\n" 2207 " ssh-agent -u\n"); 2208 exit(1); 2209 } 2210 2211 int 2212 main(int ac, char **av) 2213 { 2214 int c_flag = 0, d_flag = 0, D_flag = 0, k_flag = 0; 2215 int s_flag = 0, T_flag = 0, u_flag = 0, U_flag = 0; 2216 int sock = -1, ch, result, saved_errno; 2217 char *homedir = NULL, *shell, *format, *pidstr, *agentsocket = NULL; 2218 char *fdstr; 2219 const char *errstr = NULL; 2220 const char *ccp; 2221 #ifdef HAVE_SETRLIMIT 2222 struct rlimit rlim; 2223 #endif 2224 extern int optind; 2225 extern char *optarg; 2226 pid_t pid; 2227 char pidstrbuf[1 + 3 * sizeof pid]; 2228 size_t len; 2229 mode_t prev_mask; 2230 struct timespec timeout; 2231 struct pollfd *pfd = NULL; 2232 size_t npfd = 0; 2233 u_int maxfds; 2234 sigset_t nsigset, osigset; 2235 int socket_activated = 0; 2236 2237 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 2238 sanitise_stdfd(); 2239 2240 /* drop */ 2241 (void)setegid(getgid()); 2242 (void)setgid(getgid()); 2243 setuid(geteuid()); 2244 2245 platform_disable_tracing(0); /* strict=no */ 2246 2247 #ifdef RLIMIT_NOFILE 2248 if (getrlimit(RLIMIT_NOFILE, &rlim) == -1) 2249 fatal("%s: getrlimit: %s", __progname, strerror(errno)); 2250 #endif 2251 2252 __progname = ssh_get_progname(av[0]); 2253 seed_rng(); 2254 2255 while ((ch = getopt(ac, av, "cDdksTuUxE:a:O:P:t:")) != -1) { 2256 switch (ch) { 2257 case 'E': 2258 fingerprint_hash = ssh_digest_alg_by_name(optarg); 2259 if (fingerprint_hash == -1) 2260 fatal("Invalid hash algorithm \"%s\"", optarg); 2261 break; 2262 case 'c': 2263 if (s_flag) 2264 usage(); 2265 c_flag++; 2266 break; 2267 case 'k': 2268 k_flag++; 2269 break; 2270 case 'O': 2271 if (strcmp(optarg, "no-restrict-websafe") == 0) 2272 restrict_websafe = 0; 2273 else if (strcmp(optarg, "allow-remote-pkcs11") == 0) 2274 remote_add_provider = 1; 2275 else if ((ccp = strprefix(optarg, 2276 "websafe-allow=", 0)) != NULL) { 2277 if (websafe_allowlist != NULL) 2278 fatal("websafe-allow already set"); 2279 websafe_allowlist = xstrdup(ccp); 2280 } else 2281 fatal("Unknown -O option"); 2282 break; 2283 case 'P': 2284 if (allowed_providers != NULL) 2285 fatal("-P option already specified"); 2286 allowed_providers = xstrdup(optarg); 2287 break; 2288 case 's': 2289 if (c_flag) 2290 usage(); 2291 s_flag++; 2292 break; 2293 case 'd': 2294 if (d_flag || D_flag) 2295 usage(); 2296 d_flag++; 2297 break; 2298 case 'D': 2299 if (d_flag || D_flag) 2300 usage(); 2301 D_flag++; 2302 break; 2303 case 'a': 2304 agentsocket = optarg; 2305 break; 2306 case 't': 2307 if ((lifetime = convtime(optarg)) == -1) { 2308 fprintf(stderr, "Invalid lifetime\n"); 2309 usage(); 2310 } 2311 break; 2312 case 'T': 2313 T_flag++; 2314 break; 2315 case 'u': 2316 u_flag++; 2317 break; 2318 case 'U': 2319 U_flag++; 2320 break; 2321 case 'x': 2322 xcount = 0; 2323 break; 2324 default: 2325 usage(); 2326 } 2327 } 2328 ac -= optind; 2329 av += optind; 2330 2331 if (ac > 0 && 2332 (c_flag || k_flag || s_flag || d_flag || D_flag || u_flag)) 2333 usage(); 2334 2335 log_init(__progname, 2336 d_flag ? SYSLOG_LEVEL_DEBUG3 : SYSLOG_LEVEL_INFO, 2337 SYSLOG_FACILITY_AUTH, 1); 2338 2339 if (allowed_providers == NULL) 2340 allowed_providers = xstrdup(DEFAULT_ALLOWED_PROVIDERS); 2341 if (websafe_allowlist == NULL) 2342 websafe_allowlist = xstrdup(DEFAULT_WEBSAFE_ALLOWLIST); 2343 2344 if (ac == 0 && !c_flag && !s_flag) { 2345 shell = getenv("SHELL"); 2346 if (shell != NULL && (len = strlen(shell)) > 2 && 2347 strncmp(shell + len - 3, "csh", 3) == 0) 2348 c_flag = 1; 2349 } 2350 if (k_flag) { 2351 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 2352 if (pidstr == NULL) { 2353 fprintf(stderr, "%s not set, cannot kill agent\n", 2354 SSH_AGENTPID_ENV_NAME); 2355 exit(1); 2356 } 2357 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr); 2358 if (errstr) { 2359 fprintf(stderr, 2360 "%s=\"%s\", which is not a good PID: %s\n", 2361 SSH_AGENTPID_ENV_NAME, pidstr, errstr); 2362 exit(1); 2363 } 2364 if (kill(pid, SIGTERM) == -1) { 2365 perror("kill"); 2366 exit(1); 2367 } 2368 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 2369 printf(format, SSH_AUTHSOCKET_ENV_NAME); 2370 printf(format, SSH_AGENTPID_ENV_NAME); 2371 printf("echo Agent pid %ld killed;\n", (long)pid); 2372 exit(0); 2373 } 2374 if (u_flag) { 2375 if ((homedir = get_homedir()) == NULL) 2376 fatal("Couldn't determine home directory"); 2377 agent_cleanup_stale(homedir, u_flag > 1); 2378 printf("Deleted stale agent sockets in ~/%s\n", 2379 _PATH_SSH_AGENT_SOCKET_DIR); 2380 exit(0); 2381 } 2382 2383 /* 2384 * Minimum file descriptors: 2385 * stdio (3) + listener (1) + syslog (1 maybe) + connection (1) + 2386 * a few spare for libc / stack protectors / sanitisers, etc. 2387 */ 2388 #define SSH_AGENT_MIN_FDS (3+1+1+1+4) 2389 if (rlim.rlim_cur < SSH_AGENT_MIN_FDS) 2390 fatal("%s: file descriptor rlimit %lld too low (minimum %u)", 2391 __progname, (long long)rlim.rlim_cur, SSH_AGENT_MIN_FDS); 2392 maxfds = rlim.rlim_cur - SSH_AGENT_MIN_FDS; 2393 2394 parent_pid = getpid(); 2395 2396 /* Has the socket been provided via socket activation? */ 2397 if (agentsocket == NULL && ac == 0 && (d_flag || D_flag) && 2398 (pidstr = getenv("LISTEN_PID")) != NULL && 2399 (fdstr = getenv("LISTEN_FDS")) != NULL) { 2400 if (strcmp(fdstr, "1") != 0) { 2401 fatal("unexpected LISTEN_FDS contents " 2402 "(want: \"1\" got\"%s\"", fdstr); 2403 } 2404 if (fcntl(3, F_GETFL) == -1) 2405 fatal("LISTEN_FDS set but fd 3 unavailable"); 2406 pid = (int)strtonum(pidstr, 1, INT_MAX, &errstr); 2407 if (errstr != NULL) 2408 fatal("invalid LISTEN_PID: %s", errstr); 2409 if (pid != getpid()) 2410 fatal("bad LISTEN_PID: %d vs pid %d", pid, getpid()); 2411 debug("using socket activation on fd=3"); 2412 sock = 3; 2413 socket_activated = 1; 2414 } 2415 2416 if (sock == -1 && agentsocket == NULL && !T_flag) { 2417 /* Default case: ~/.ssh/agent/[socket] */ 2418 if ((homedir = get_homedir()) == NULL) 2419 fatal("Couldn't determine home directory"); 2420 if (!U_flag) 2421 agent_cleanup_stale(homedir, 0); 2422 if (agent_listener(homedir, "agent", &sock, &agentsocket) != 0) 2423 fatal_f("Couldn't prepare agent socket"); 2424 if (strlcpy(socket_name, agentsocket, 2425 sizeof(socket_name)) >= sizeof(socket_name)) { 2426 fatal_f("Socket path \"%s\" too long", 2427 agentsocket); 2428 } 2429 free(homedir); 2430 free(agentsocket); 2431 agentsocket = NULL; 2432 } else if (sock == -1) { 2433 if (T_flag) { 2434 /* 2435 * Create private directory for agent socket 2436 * in $TMPDIR. 2437 */ 2438 mktemp_proto(socket_dir, sizeof(socket_dir)); 2439 if (mkdtemp(socket_dir) == NULL) { 2440 perror("mkdtemp: private socket dir"); 2441 exit(1); 2442 } 2443 snprintf(socket_name, sizeof(socket_name), 2444 "%s/agent.%ld", socket_dir, (long)parent_pid); 2445 } else { 2446 /* Try to use specified agent socket */ 2447 socket_dir[0] = '\0'; 2448 if (strlcpy(socket_name, agentsocket, 2449 sizeof(socket_name)) >= sizeof(socket_name)) { 2450 fatal_f("Socket path \"%s\" too long", 2451 agentsocket); 2452 } 2453 } 2454 /* Listen on socket */ 2455 prev_mask = umask(0177); 2456 if ((sock = unix_listener(socket_name, 2457 SSH_LISTEN_BACKLOG, 0)) < 0) { 2458 *socket_name = '\0'; /* Don't unlink existing file */ 2459 cleanup_exit(1); 2460 } 2461 umask(prev_mask); 2462 } 2463 2464 closefrom(sock == -1 ? STDERR_FILENO + 1 : sock + 1); 2465 2466 /* 2467 * Create socket early so it will exist before command gets run from 2468 * the parent. 2469 */ 2470 if (sock == -1) { 2471 prev_mask = umask(0177); 2472 sock = unix_listener(socket_name, SSH_LISTEN_BACKLOG, 0); 2473 if (sock < 0) { 2474 /* XXX - unix_listener() calls error() not perror() */ 2475 *socket_name = '\0'; /* Don't unlink existing file */ 2476 cleanup_exit(1); 2477 } 2478 umask(prev_mask); 2479 } 2480 2481 /* 2482 * Fork, and have the parent execute the command, if any, or present 2483 * the socket data. The child continues as the authentication agent. 2484 */ 2485 if (D_flag || d_flag) { 2486 log_init(__progname, 2487 d_flag ? SYSLOG_LEVEL_DEBUG3 : SYSLOG_LEVEL_INFO, 2488 SYSLOG_FACILITY_AUTH, 1); 2489 if (socket_name[0] != '\0') { 2490 format = c_flag ? 2491 "setenv %s %s;\n" : "%s=%s; export %s;\n"; 2492 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 2493 SSH_AUTHSOCKET_ENV_NAME); 2494 printf("echo Agent pid %ld;\n", (long)parent_pid); 2495 fflush(stdout); 2496 } 2497 goto skip; 2498 } 2499 pid = fork(); 2500 if (pid == -1) { 2501 perror("fork"); 2502 cleanup_exit(1); 2503 } 2504 if (pid != 0) { /* Parent - execute the given command. */ 2505 close(sock); 2506 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 2507 if (ac == 0) { 2508 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 2509 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 2510 SSH_AUTHSOCKET_ENV_NAME); 2511 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 2512 SSH_AGENTPID_ENV_NAME); 2513 printf("echo Agent pid %ld;\n", (long)pid); 2514 exit(0); 2515 } 2516 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 2517 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 2518 perror("setenv"); 2519 exit(1); 2520 } 2521 execvp(av[0], av); 2522 perror(av[0]); 2523 exit(1); 2524 } 2525 /* child */ 2526 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 2527 2528 if (setsid() == -1) { 2529 error("setsid: %s", strerror(errno)); 2530 cleanup_exit(1); 2531 } 2532 2533 (void)chdir("/"); 2534 if (stdfd_devnull(1, 1, 1) == -1) 2535 error_f("stdfd_devnull failed"); 2536 2537 #ifdef HAVE_SETRLIMIT 2538 /* deny core dumps, since memory contains unencrypted private keys */ 2539 rlim.rlim_cur = rlim.rlim_max = 0; 2540 if (setrlimit(RLIMIT_CORE, &rlim) == -1) { 2541 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 2542 cleanup_exit(1); 2543 } 2544 #endif 2545 2546 skip: 2547 2548 cleanup_pid = getpid(); 2549 2550 #ifdef ENABLE_PKCS11 2551 pkcs11_init(0); 2552 #endif 2553 new_socket(AUTH_SOCKET, sock); 2554 if (ac > 0) 2555 parent_alive_interval = 10; 2556 idtab_init(); 2557 ssh_signal(SIGPIPE, SIG_IGN); 2558 ssh_signal(SIGINT, (d_flag | D_flag) ? cleanup_handler : SIG_IGN); 2559 ssh_signal(SIGHUP, cleanup_handler); 2560 ssh_signal(SIGTERM, cleanup_handler); 2561 ssh_signal(SIGUSR1, keydrop_handler); 2562 2563 sigemptyset(&nsigset); 2564 sigaddset(&nsigset, SIGINT); 2565 sigaddset(&nsigset, SIGHUP); 2566 sigaddset(&nsigset, SIGTERM); 2567 sigaddset(&nsigset, SIGUSR1); 2568 2569 if (pledge("stdio rpath cpath unix id proc exec", NULL) == -1) 2570 fatal("%s: pledge: %s", __progname, strerror(errno)); 2571 platform_pledge_agent(); 2572 2573 while (1) { 2574 sigprocmask(SIG_BLOCK, &nsigset, &osigset); 2575 if (signalled_exit != 0) { 2576 logit("exiting on signal %d", (int)signalled_exit); 2577 cleanup_exit((signalled_exit == SIGTERM && 2578 socket_activated) ? 0 : 2); 2579 } 2580 if (signalled_keydrop) { 2581 logit("signal %d received; removing all keys", 2582 (int)signalled_keydrop); 2583 remove_all_identities(); 2584 signalled_keydrop = 0; 2585 } 2586 ptimeout_init(&timeout); 2587 prepare_poll(&pfd, &npfd, &timeout, maxfds); 2588 result = ppoll(pfd, npfd, ptimeout_get_tsp(&timeout), &osigset); 2589 sigprocmask(SIG_SETMASK, &osigset, NULL); 2590 saved_errno = errno; 2591 if (parent_alive_interval != 0) 2592 check_parent_exists(); 2593 (void) reaper(); /* remove expired keys */ 2594 if (result == -1) { 2595 if (saved_errno == EINTR) 2596 continue; 2597 fatal("poll: %s", strerror(saved_errno)); 2598 } else if (result > 0) 2599 after_poll(pfd, npfd, maxfds); 2600 } 2601 /* NOTREACHED */ 2602 } 2603