1 /* $OpenBSD: ssh-agent.c,v 1.218 2017/03/15 03:52:30 deraadt 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 __RCSID("$FreeBSD$"); 39 40 #include <sys/types.h> 41 #include <sys/param.h> 42 #include <sys/resource.h> 43 #include <sys/stat.h> 44 #include <sys/socket.h> 45 #ifdef HAVE_SYS_TIME_H 46 # include <sys/time.h> 47 #endif 48 #ifdef HAVE_SYS_UN_H 49 # include <sys/un.h> 50 #endif 51 #include "openbsd-compat/sys-queue.h" 52 53 #ifdef WITH_OPENSSL 54 #include <openssl/evp.h> 55 #include "openbsd-compat/openssl-compat.h" 56 #endif 57 58 #include <errno.h> 59 #include <fcntl.h> 60 #include <limits.h> 61 #ifdef HAVE_PATHS_H 62 # include <paths.h> 63 #endif 64 #include <signal.h> 65 #include <stdarg.h> 66 #include <stdio.h> 67 #include <stdlib.h> 68 #include <time.h> 69 #include <string.h> 70 #include <unistd.h> 71 #ifdef HAVE_UTIL_H 72 # include <util.h> 73 #endif 74 75 #include "xmalloc.h" 76 #include "ssh.h" 77 #include "rsa.h" 78 #include "sshbuf.h" 79 #include "sshkey.h" 80 #include "authfd.h" 81 #include "compat.h" 82 #include "log.h" 83 #include "misc.h" 84 #include "digest.h" 85 #include "ssherr.h" 86 #include "match.h" 87 88 #ifdef ENABLE_PKCS11 89 #include "ssh-pkcs11.h" 90 #endif 91 92 #ifndef DEFAULT_PKCS11_WHITELIST 93 # define DEFAULT_PKCS11_WHITELIST "/usr/lib*/*,/usr/local/lib*/*" 94 #endif 95 96 typedef enum { 97 AUTH_UNUSED, 98 AUTH_SOCKET, 99 AUTH_CONNECTION 100 } sock_type; 101 102 typedef struct { 103 int fd; 104 sock_type type; 105 struct sshbuf *input; 106 struct sshbuf *output; 107 struct sshbuf *request; 108 } SocketEntry; 109 110 u_int sockets_alloc = 0; 111 SocketEntry *sockets = NULL; 112 113 typedef struct identity { 114 TAILQ_ENTRY(identity) next; 115 struct sshkey *key; 116 char *comment; 117 char *provider; 118 time_t death; 119 u_int confirm; 120 } Identity; 121 122 typedef struct { 123 int nentries; 124 TAILQ_HEAD(idqueue, identity) idlist; 125 } Idtab; 126 127 /* private key table, one per protocol version */ 128 Idtab idtable[3]; 129 130 int max_fd = 0; 131 132 /* pid of shell == parent of agent */ 133 pid_t parent_pid = -1; 134 time_t parent_alive_interval = 0; 135 136 /* pid of process for which cleanup_socket is applicable */ 137 pid_t cleanup_pid = 0; 138 139 /* pathname and directory for AUTH_SOCKET */ 140 char socket_name[PATH_MAX]; 141 char socket_dir[PATH_MAX]; 142 143 /* PKCS#11 path whitelist */ 144 static char *pkcs11_whitelist; 145 146 /* locking */ 147 #define LOCK_SIZE 32 148 #define LOCK_SALT_SIZE 16 149 #define LOCK_ROUNDS 1 150 int locked = 0; 151 u_char lock_pwhash[LOCK_SIZE]; 152 u_char lock_salt[LOCK_SALT_SIZE]; 153 154 extern char *__progname; 155 156 /* Default lifetime in seconds (0 == forever) */ 157 static long lifetime = 0; 158 159 static int fingerprint_hash = SSH_FP_HASH_DEFAULT; 160 161 /* 162 * Client connection count; incremented in new_socket() and decremented in 163 * close_socket(). When it reaches 0, ssh-agent will exit. Since it is 164 * normally initialized to 1, it will never reach 0. However, if the -x 165 * option is specified, it is initialized to 0 in main(); in that case, 166 * ssh-agent will exit as soon as it has had at least one client but no 167 * longer has any. 168 */ 169 static int xcount = 1; 170 171 static void 172 close_socket(SocketEntry *e) 173 { 174 int last = 0; 175 176 if (e->type == AUTH_CONNECTION) { 177 debug("xcount %d -> %d", xcount, xcount - 1); 178 if (--xcount == 0) 179 last = 1; 180 } 181 close(e->fd); 182 e->fd = -1; 183 e->type = AUTH_UNUSED; 184 sshbuf_free(e->input); 185 sshbuf_free(e->output); 186 sshbuf_free(e->request); 187 if (last) 188 cleanup_exit(0); 189 } 190 191 static void 192 idtab_init(void) 193 { 194 int i; 195 196 for (i = 0; i <=2; i++) { 197 TAILQ_INIT(&idtable[i].idlist); 198 idtable[i].nentries = 0; 199 } 200 } 201 202 /* return private key table for requested protocol version */ 203 static Idtab * 204 idtab_lookup(int version) 205 { 206 if (version < 1 || version > 2) 207 fatal("internal error, bad protocol version %d", version); 208 return &idtable[version]; 209 } 210 211 static void 212 free_identity(Identity *id) 213 { 214 sshkey_free(id->key); 215 free(id->provider); 216 free(id->comment); 217 free(id); 218 } 219 220 /* return matching private key for given public key */ 221 static Identity * 222 lookup_identity(struct sshkey *key, int version) 223 { 224 Identity *id; 225 226 Idtab *tab = idtab_lookup(version); 227 TAILQ_FOREACH(id, &tab->idlist, next) { 228 if (sshkey_equal(key, id->key)) 229 return (id); 230 } 231 return (NULL); 232 } 233 234 /* Check confirmation of keysign request */ 235 static int 236 confirm_key(Identity *id) 237 { 238 char *p; 239 int ret = -1; 240 241 p = sshkey_fingerprint(id->key, fingerprint_hash, SSH_FP_DEFAULT); 242 if (p != NULL && 243 ask_permission("Allow use of key %s?\nKey fingerprint %s.", 244 id->comment, p)) 245 ret = 0; 246 free(p); 247 248 return (ret); 249 } 250 251 static void 252 send_status(SocketEntry *e, int success) 253 { 254 int r; 255 256 if ((r = sshbuf_put_u32(e->output, 1)) != 0 || 257 (r = sshbuf_put_u8(e->output, success ? 258 SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0) 259 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 260 } 261 262 /* send list of supported public keys to 'client' */ 263 static void 264 process_request_identities(SocketEntry *e, int version) 265 { 266 Idtab *tab = idtab_lookup(version); 267 Identity *id; 268 struct sshbuf *msg; 269 int r; 270 271 if ((msg = sshbuf_new()) == NULL) 272 fatal("%s: sshbuf_new failed", __func__); 273 if ((r = sshbuf_put_u8(msg, (version == 1) ? 274 SSH_AGENT_RSA_IDENTITIES_ANSWER : 275 SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 276 (r = sshbuf_put_u32(msg, tab->nentries)) != 0) 277 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 278 TAILQ_FOREACH(id, &tab->idlist, next) { 279 if (id->key->type == KEY_RSA1) { 280 #ifdef WITH_SSH1 281 if ((r = sshbuf_put_u32(msg, 282 BN_num_bits(id->key->rsa->n))) != 0 || 283 (r = sshbuf_put_bignum1(msg, 284 id->key->rsa->e)) != 0 || 285 (r = sshbuf_put_bignum1(msg, 286 id->key->rsa->n)) != 0) 287 fatal("%s: buffer error: %s", 288 __func__, ssh_err(r)); 289 #endif 290 } else { 291 u_char *blob; 292 size_t blen; 293 294 if ((r = sshkey_to_blob(id->key, &blob, &blen)) != 0) { 295 error("%s: sshkey_to_blob: %s", __func__, 296 ssh_err(r)); 297 continue; 298 } 299 if ((r = sshbuf_put_string(msg, blob, blen)) != 0) 300 fatal("%s: buffer error: %s", 301 __func__, ssh_err(r)); 302 free(blob); 303 } 304 if ((r = sshbuf_put_cstring(msg, id->comment)) != 0) 305 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 306 } 307 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 308 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 309 sshbuf_free(msg); 310 } 311 312 #ifdef WITH_SSH1 313 /* ssh1 only */ 314 static void 315 process_authentication_challenge1(SocketEntry *e) 316 { 317 u_char buf[32], mdbuf[16], session_id[16]; 318 u_int response_type; 319 BIGNUM *challenge; 320 Identity *id; 321 int r, len; 322 struct sshbuf *msg; 323 struct ssh_digest_ctx *md; 324 struct sshkey *key; 325 326 if ((msg = sshbuf_new()) == NULL) 327 fatal("%s: sshbuf_new failed", __func__); 328 if ((key = sshkey_new(KEY_RSA1)) == NULL) 329 fatal("%s: sshkey_new failed", __func__); 330 if ((challenge = BN_new()) == NULL) 331 fatal("%s: BN_new failed", __func__); 332 333 if ((r = sshbuf_get_u32(e->request, NULL)) != 0 || /* ignored */ 334 (r = sshbuf_get_bignum1(e->request, key->rsa->e)) != 0 || 335 (r = sshbuf_get_bignum1(e->request, key->rsa->n)) != 0 || 336 (r = sshbuf_get_bignum1(e->request, challenge))) 337 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 338 339 /* Only protocol 1.1 is supported */ 340 if (sshbuf_len(e->request) == 0) 341 goto failure; 342 if ((r = sshbuf_get(e->request, session_id, sizeof(session_id))) != 0 || 343 (r = sshbuf_get_u32(e->request, &response_type)) != 0) 344 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 345 if (response_type != 1) 346 goto failure; 347 348 id = lookup_identity(key, 1); 349 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) { 350 struct sshkey *private = id->key; 351 /* Decrypt the challenge using the private key. */ 352 if ((r = rsa_private_decrypt(challenge, challenge, 353 private->rsa) != 0)) { 354 fatal("%s: rsa_public_encrypt: %s", __func__, 355 ssh_err(r)); 356 goto failure; /* XXX ? */ 357 } 358 359 /* The response is MD5 of decrypted challenge plus session id */ 360 len = BN_num_bytes(challenge); 361 if (len <= 0 || len > 32) { 362 logit("%s: bad challenge length %d", __func__, len); 363 goto failure; 364 } 365 memset(buf, 0, 32); 366 BN_bn2bin(challenge, buf + 32 - len); 367 if ((md = ssh_digest_start(SSH_DIGEST_MD5)) == NULL || 368 ssh_digest_update(md, buf, 32) < 0 || 369 ssh_digest_update(md, session_id, 16) < 0 || 370 ssh_digest_final(md, mdbuf, sizeof(mdbuf)) < 0) 371 fatal("%s: md5 failed", __func__); 372 ssh_digest_free(md); 373 374 /* Send the response. */ 375 if ((r = sshbuf_put_u8(msg, SSH_AGENT_RSA_RESPONSE)) != 0 || 376 (r = sshbuf_put(msg, mdbuf, sizeof(mdbuf))) != 0) 377 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 378 goto send; 379 } 380 381 failure: 382 /* Unknown identity or protocol error. Send failure. */ 383 if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0) 384 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 385 send: 386 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 387 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 388 sshkey_free(key); 389 BN_clear_free(challenge); 390 sshbuf_free(msg); 391 } 392 #endif 393 394 static char * 395 agent_decode_alg(struct sshkey *key, u_int flags) 396 { 397 if (key->type == KEY_RSA) { 398 if (flags & SSH_AGENT_RSA_SHA2_256) 399 return "rsa-sha2-256"; 400 else if (flags & SSH_AGENT_RSA_SHA2_512) 401 return "rsa-sha2-512"; 402 } 403 return NULL; 404 } 405 406 /* ssh2 only */ 407 static void 408 process_sign_request2(SocketEntry *e) 409 { 410 u_char *blob, *data, *signature = NULL; 411 size_t blen, dlen, slen = 0; 412 u_int compat = 0, flags; 413 int r, ok = -1; 414 struct sshbuf *msg; 415 struct sshkey *key; 416 struct identity *id; 417 418 if ((msg = sshbuf_new()) == NULL) 419 fatal("%s: sshbuf_new failed", __func__); 420 if ((r = sshbuf_get_string(e->request, &blob, &blen)) != 0 || 421 (r = sshbuf_get_string(e->request, &data, &dlen)) != 0 || 422 (r = sshbuf_get_u32(e->request, &flags)) != 0) 423 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 424 if (flags & SSH_AGENT_OLD_SIGNATURE) 425 compat = SSH_BUG_SIGBLOB; 426 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) { 427 error("%s: cannot parse key blob: %s", __func__, ssh_err(r)); 428 goto send; 429 } 430 if ((id = lookup_identity(key, 2)) == NULL) { 431 verbose("%s: %s key not found", __func__, sshkey_type(key)); 432 goto send; 433 } 434 if (id->confirm && confirm_key(id) != 0) { 435 verbose("%s: user refused key", __func__); 436 goto send; 437 } 438 if ((r = sshkey_sign(id->key, &signature, &slen, 439 data, dlen, agent_decode_alg(key, flags), compat)) != 0) { 440 error("%s: sshkey_sign: %s", __func__, ssh_err(r)); 441 goto send; 442 } 443 /* Success */ 444 ok = 0; 445 send: 446 sshkey_free(key); 447 if (ok == 0) { 448 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 || 449 (r = sshbuf_put_string(msg, signature, slen)) != 0) 450 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 451 } else if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0) 452 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 453 454 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 455 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 456 457 sshbuf_free(msg); 458 free(data); 459 free(blob); 460 free(signature); 461 } 462 463 /* shared */ 464 static void 465 process_remove_identity(SocketEntry *e, int version) 466 { 467 size_t blen; 468 int r, success = 0; 469 struct sshkey *key = NULL; 470 u_char *blob; 471 #ifdef WITH_SSH1 472 u_int bits; 473 #endif /* WITH_SSH1 */ 474 475 switch (version) { 476 #ifdef WITH_SSH1 477 case 1: 478 if ((key = sshkey_new(KEY_RSA1)) == NULL) { 479 error("%s: sshkey_new failed", __func__); 480 return; 481 } 482 if ((r = sshbuf_get_u32(e->request, &bits)) != 0 || 483 (r = sshbuf_get_bignum1(e->request, key->rsa->e)) != 0 || 484 (r = sshbuf_get_bignum1(e->request, key->rsa->n)) != 0) 485 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 486 487 if (bits != sshkey_size(key)) 488 logit("Warning: identity keysize mismatch: " 489 "actual %u, announced %u", 490 sshkey_size(key), bits); 491 break; 492 #endif /* WITH_SSH1 */ 493 case 2: 494 if ((r = sshbuf_get_string(e->request, &blob, &blen)) != 0) 495 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 496 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) 497 error("%s: sshkey_from_blob failed: %s", 498 __func__, ssh_err(r)); 499 free(blob); 500 break; 501 } 502 if (key != NULL) { 503 Identity *id = lookup_identity(key, version); 504 if (id != NULL) { 505 /* 506 * We have this key. Free the old key. Since we 507 * don't want to leave empty slots in the middle of 508 * the array, we actually free the key there and move 509 * all the entries between the empty slot and the end 510 * of the array. 511 */ 512 Idtab *tab = idtab_lookup(version); 513 if (tab->nentries < 1) 514 fatal("process_remove_identity: " 515 "internal error: tab->nentries %d", 516 tab->nentries); 517 TAILQ_REMOVE(&tab->idlist, id, next); 518 free_identity(id); 519 tab->nentries--; 520 success = 1; 521 } 522 sshkey_free(key); 523 } 524 send_status(e, success); 525 } 526 527 static void 528 process_remove_all_identities(SocketEntry *e, int version) 529 { 530 Idtab *tab = idtab_lookup(version); 531 Identity *id; 532 533 /* Loop over all identities and clear the keys. */ 534 for (id = TAILQ_FIRST(&tab->idlist); id; 535 id = TAILQ_FIRST(&tab->idlist)) { 536 TAILQ_REMOVE(&tab->idlist, id, next); 537 free_identity(id); 538 } 539 540 /* Mark that there are no identities. */ 541 tab->nentries = 0; 542 543 /* Send success. */ 544 send_status(e, 1); 545 } 546 547 /* removes expired keys and returns number of seconds until the next expiry */ 548 static time_t 549 reaper(void) 550 { 551 time_t deadline = 0, now = monotime(); 552 Identity *id, *nxt; 553 int version; 554 Idtab *tab; 555 556 for (version = 1; version < 3; version++) { 557 tab = idtab_lookup(version); 558 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 559 nxt = TAILQ_NEXT(id, next); 560 if (id->death == 0) 561 continue; 562 if (now >= id->death) { 563 debug("expiring key '%s'", id->comment); 564 TAILQ_REMOVE(&tab->idlist, id, next); 565 free_identity(id); 566 tab->nentries--; 567 } else 568 deadline = (deadline == 0) ? id->death : 569 MINIMUM(deadline, id->death); 570 } 571 } 572 if (deadline == 0 || deadline <= now) 573 return 0; 574 else 575 return (deadline - now); 576 } 577 578 /* 579 * XXX this and the corresponding serialisation function probably belongs 580 * in key.c 581 */ 582 #ifdef WITH_SSH1 583 static int 584 agent_decode_rsa1(struct sshbuf *m, struct sshkey **kp) 585 { 586 struct sshkey *k = NULL; 587 int r = SSH_ERR_INTERNAL_ERROR; 588 589 *kp = NULL; 590 if ((k = sshkey_new_private(KEY_RSA1)) == NULL) 591 return SSH_ERR_ALLOC_FAIL; 592 593 if ((r = sshbuf_get_u32(m, NULL)) != 0 || /* ignored */ 594 (r = sshbuf_get_bignum1(m, k->rsa->n)) != 0 || 595 (r = sshbuf_get_bignum1(m, k->rsa->e)) != 0 || 596 (r = sshbuf_get_bignum1(m, k->rsa->d)) != 0 || 597 (r = sshbuf_get_bignum1(m, k->rsa->iqmp)) != 0 || 598 /* SSH1 and SSL have p and q swapped */ 599 (r = sshbuf_get_bignum1(m, k->rsa->q)) != 0 || /* p */ 600 (r = sshbuf_get_bignum1(m, k->rsa->p)) != 0) /* q */ 601 goto out; 602 603 /* Generate additional parameters */ 604 if ((r = rsa_generate_additional_parameters(k->rsa)) != 0) 605 goto out; 606 /* enable blinding */ 607 if (RSA_blinding_on(k->rsa, NULL) != 1) { 608 r = SSH_ERR_LIBCRYPTO_ERROR; 609 goto out; 610 } 611 612 r = 0; /* success */ 613 out: 614 if (r == 0) 615 *kp = k; 616 else 617 sshkey_free(k); 618 return r; 619 } 620 #endif /* WITH_SSH1 */ 621 622 static void 623 process_add_identity(SocketEntry *e, int version) 624 { 625 Idtab *tab = idtab_lookup(version); 626 Identity *id; 627 int success = 0, confirm = 0; 628 u_int seconds; 629 char *comment = NULL; 630 time_t death = 0; 631 struct sshkey *k = NULL; 632 u_char ctype; 633 int r = SSH_ERR_INTERNAL_ERROR; 634 635 switch (version) { 636 #ifdef WITH_SSH1 637 case 1: 638 r = agent_decode_rsa1(e->request, &k); 639 break; 640 #endif /* WITH_SSH1 */ 641 case 2: 642 r = sshkey_private_deserialize(e->request, &k); 643 break; 644 } 645 if (r != 0 || k == NULL || 646 (r = sshbuf_get_cstring(e->request, &comment, NULL)) != 0) { 647 error("%s: decode private key: %s", __func__, ssh_err(r)); 648 goto err; 649 } 650 651 while (sshbuf_len(e->request)) { 652 if ((r = sshbuf_get_u8(e->request, &ctype)) != 0) { 653 error("%s: buffer error: %s", __func__, ssh_err(r)); 654 goto err; 655 } 656 switch (ctype) { 657 case SSH_AGENT_CONSTRAIN_LIFETIME: 658 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) { 659 error("%s: bad lifetime constraint: %s", 660 __func__, ssh_err(r)); 661 goto err; 662 } 663 death = monotime() + seconds; 664 break; 665 case SSH_AGENT_CONSTRAIN_CONFIRM: 666 confirm = 1; 667 break; 668 default: 669 error("%s: Unknown constraint %d", __func__, ctype); 670 err: 671 sshbuf_reset(e->request); 672 free(comment); 673 sshkey_free(k); 674 goto send; 675 } 676 } 677 678 success = 1; 679 if (lifetime && !death) 680 death = monotime() + lifetime; 681 if ((id = lookup_identity(k, version)) == NULL) { 682 id = xcalloc(1, sizeof(Identity)); 683 id->key = k; 684 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 685 /* Increment the number of identities. */ 686 tab->nentries++; 687 } else { 688 sshkey_free(k); 689 free(id->comment); 690 } 691 id->comment = comment; 692 id->death = death; 693 id->confirm = confirm; 694 send: 695 send_status(e, success); 696 } 697 698 /* XXX todo: encrypt sensitive data with passphrase */ 699 static void 700 process_lock_agent(SocketEntry *e, int lock) 701 { 702 int r, success = 0, delay; 703 char *passwd; 704 u_char passwdhash[LOCK_SIZE]; 705 static u_int fail_count = 0; 706 size_t pwlen; 707 708 if ((r = sshbuf_get_cstring(e->request, &passwd, &pwlen)) != 0) 709 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 710 if (pwlen == 0) { 711 debug("empty password not supported"); 712 } else if (locked && !lock) { 713 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 714 passwdhash, sizeof(passwdhash), LOCK_ROUNDS) < 0) 715 fatal("bcrypt_pbkdf"); 716 if (timingsafe_bcmp(passwdhash, lock_pwhash, LOCK_SIZE) == 0) { 717 debug("agent unlocked"); 718 locked = 0; 719 fail_count = 0; 720 explicit_bzero(lock_pwhash, sizeof(lock_pwhash)); 721 success = 1; 722 } else { 723 /* delay in 0.1s increments up to 10s */ 724 if (fail_count < 100) 725 fail_count++; 726 delay = 100000 * fail_count; 727 debug("unlock failed, delaying %0.1lf seconds", 728 (double)delay/1000000); 729 usleep(delay); 730 } 731 explicit_bzero(passwdhash, sizeof(passwdhash)); 732 } else if (!locked && lock) { 733 debug("agent locked"); 734 locked = 1; 735 arc4random_buf(lock_salt, sizeof(lock_salt)); 736 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 737 lock_pwhash, sizeof(lock_pwhash), LOCK_ROUNDS) < 0) 738 fatal("bcrypt_pbkdf"); 739 success = 1; 740 } 741 explicit_bzero(passwd, pwlen); 742 free(passwd); 743 send_status(e, success); 744 } 745 746 static void 747 no_identities(SocketEntry *e, u_int type) 748 { 749 struct sshbuf *msg; 750 int r; 751 752 if ((msg = sshbuf_new()) == NULL) 753 fatal("%s: sshbuf_new failed", __func__); 754 if ((r = sshbuf_put_u8(msg, 755 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ? 756 SSH_AGENT_RSA_IDENTITIES_ANSWER : 757 SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 758 (r = sshbuf_put_u32(msg, 0)) != 0 || 759 (r = sshbuf_put_stringb(e->output, msg)) != 0) 760 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 761 sshbuf_free(msg); 762 } 763 764 #ifdef ENABLE_PKCS11 765 static void 766 process_add_smartcard_key(SocketEntry *e) 767 { 768 char *provider = NULL, *pin, canonical_provider[PATH_MAX]; 769 int r, i, version, count = 0, success = 0, confirm = 0; 770 u_int seconds; 771 time_t death = 0; 772 u_char type; 773 struct sshkey **keys = NULL, *k; 774 Identity *id; 775 Idtab *tab; 776 777 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 778 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) 779 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 780 781 while (sshbuf_len(e->request)) { 782 if ((r = sshbuf_get_u8(e->request, &type)) != 0) 783 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 784 switch (type) { 785 case SSH_AGENT_CONSTRAIN_LIFETIME: 786 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) 787 fatal("%s: buffer error: %s", 788 __func__, ssh_err(r)); 789 death = monotime() + seconds; 790 break; 791 case SSH_AGENT_CONSTRAIN_CONFIRM: 792 confirm = 1; 793 break; 794 default: 795 error("process_add_smartcard_key: " 796 "Unknown constraint type %d", type); 797 goto send; 798 } 799 } 800 if (realpath(provider, canonical_provider) == NULL) { 801 verbose("failed PKCS#11 add of \"%.100s\": realpath: %s", 802 provider, strerror(errno)); 803 goto send; 804 } 805 if (match_pattern_list(canonical_provider, pkcs11_whitelist, 0) != 1) { 806 verbose("refusing PKCS#11 add of \"%.100s\": " 807 "provider not whitelisted", canonical_provider); 808 goto send; 809 } 810 debug("%s: add %.100s", __func__, canonical_provider); 811 if (lifetime && !death) 812 death = monotime() + lifetime; 813 814 count = pkcs11_add_provider(canonical_provider, pin, &keys); 815 for (i = 0; i < count; i++) { 816 k = keys[i]; 817 version = k->type == KEY_RSA1 ? 1 : 2; 818 tab = idtab_lookup(version); 819 if (lookup_identity(k, version) == NULL) { 820 id = xcalloc(1, sizeof(Identity)); 821 id->key = k; 822 id->provider = xstrdup(canonical_provider); 823 id->comment = xstrdup(canonical_provider); /* XXX */ 824 id->death = death; 825 id->confirm = confirm; 826 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 827 tab->nentries++; 828 success = 1; 829 } else { 830 sshkey_free(k); 831 } 832 keys[i] = NULL; 833 } 834 send: 835 free(pin); 836 free(provider); 837 free(keys); 838 send_status(e, success); 839 } 840 841 static void 842 process_remove_smartcard_key(SocketEntry *e) 843 { 844 char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX]; 845 int r, version, success = 0; 846 Identity *id, *nxt; 847 Idtab *tab; 848 849 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 850 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) 851 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 852 free(pin); 853 854 if (realpath(provider, canonical_provider) == NULL) { 855 verbose("failed PKCS#11 add of \"%.100s\": realpath: %s", 856 provider, strerror(errno)); 857 goto send; 858 } 859 860 debug("%s: remove %.100s", __func__, canonical_provider); 861 for (version = 1; version < 3; version++) { 862 tab = idtab_lookup(version); 863 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 864 nxt = TAILQ_NEXT(id, next); 865 /* Skip file--based keys */ 866 if (id->provider == NULL) 867 continue; 868 if (!strcmp(canonical_provider, id->provider)) { 869 TAILQ_REMOVE(&tab->idlist, id, next); 870 free_identity(id); 871 tab->nentries--; 872 } 873 } 874 } 875 if (pkcs11_del_provider(canonical_provider) == 0) 876 success = 1; 877 else 878 error("process_remove_smartcard_key:" 879 " pkcs11_del_provider failed"); 880 send: 881 free(provider); 882 send_status(e, success); 883 } 884 #endif /* ENABLE_PKCS11 */ 885 886 /* dispatch incoming messages */ 887 888 static void 889 process_message(SocketEntry *e) 890 { 891 u_int msg_len; 892 u_char type; 893 const u_char *cp; 894 int r; 895 896 if (sshbuf_len(e->input) < 5) 897 return; /* Incomplete message. */ 898 cp = sshbuf_ptr(e->input); 899 msg_len = PEEK_U32(cp); 900 if (msg_len > 256 * 1024) { 901 close_socket(e); 902 return; 903 } 904 if (sshbuf_len(e->input) < msg_len + 4) 905 return; 906 907 /* move the current input to e->request */ 908 sshbuf_reset(e->request); 909 if ((r = sshbuf_get_stringb(e->input, e->request)) != 0 || 910 (r = sshbuf_get_u8(e->request, &type)) != 0) 911 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 912 913 /* check wheter agent is locked */ 914 if (locked && type != SSH_AGENTC_UNLOCK) { 915 sshbuf_reset(e->request); 916 switch (type) { 917 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 918 case SSH2_AGENTC_REQUEST_IDENTITIES: 919 /* send empty lists */ 920 no_identities(e, type); 921 break; 922 default: 923 /* send a fail message for all other request types */ 924 send_status(e, 0); 925 } 926 return; 927 } 928 929 debug("type %d", type); 930 switch (type) { 931 case SSH_AGENTC_LOCK: 932 case SSH_AGENTC_UNLOCK: 933 process_lock_agent(e, type == SSH_AGENTC_LOCK); 934 break; 935 #ifdef WITH_SSH1 936 /* ssh1 */ 937 case SSH_AGENTC_RSA_CHALLENGE: 938 process_authentication_challenge1(e); 939 break; 940 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 941 process_request_identities(e, 1); 942 break; 943 case SSH_AGENTC_ADD_RSA_IDENTITY: 944 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 945 process_add_identity(e, 1); 946 break; 947 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 948 process_remove_identity(e, 1); 949 break; 950 #endif 951 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 952 process_remove_all_identities(e, 1); /* safe for !WITH_SSH1 */ 953 break; 954 /* ssh2 */ 955 case SSH2_AGENTC_SIGN_REQUEST: 956 process_sign_request2(e); 957 break; 958 case SSH2_AGENTC_REQUEST_IDENTITIES: 959 process_request_identities(e, 2); 960 break; 961 case SSH2_AGENTC_ADD_IDENTITY: 962 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 963 process_add_identity(e, 2); 964 break; 965 case SSH2_AGENTC_REMOVE_IDENTITY: 966 process_remove_identity(e, 2); 967 break; 968 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 969 process_remove_all_identities(e, 2); 970 break; 971 #ifdef ENABLE_PKCS11 972 case SSH_AGENTC_ADD_SMARTCARD_KEY: 973 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 974 process_add_smartcard_key(e); 975 break; 976 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 977 process_remove_smartcard_key(e); 978 break; 979 #endif /* ENABLE_PKCS11 */ 980 default: 981 /* Unknown message. Respond with failure. */ 982 error("Unknown message %d", type); 983 sshbuf_reset(e->request); 984 send_status(e, 0); 985 break; 986 } 987 } 988 989 static void 990 new_socket(sock_type type, int fd) 991 { 992 u_int i, old_alloc, new_alloc; 993 994 if (type == AUTH_CONNECTION) { 995 debug("xcount %d -> %d", xcount, xcount + 1); 996 ++xcount; 997 } 998 set_nonblock(fd); 999 1000 if (fd > max_fd) 1001 max_fd = fd; 1002 1003 for (i = 0; i < sockets_alloc; i++) 1004 if (sockets[i].type == AUTH_UNUSED) { 1005 sockets[i].fd = fd; 1006 if ((sockets[i].input = sshbuf_new()) == NULL) 1007 fatal("%s: sshbuf_new failed", __func__); 1008 if ((sockets[i].output = sshbuf_new()) == NULL) 1009 fatal("%s: sshbuf_new failed", __func__); 1010 if ((sockets[i].request = sshbuf_new()) == NULL) 1011 fatal("%s: sshbuf_new failed", __func__); 1012 sockets[i].type = type; 1013 return; 1014 } 1015 old_alloc = sockets_alloc; 1016 new_alloc = sockets_alloc + 10; 1017 sockets = xreallocarray(sockets, new_alloc, sizeof(sockets[0])); 1018 for (i = old_alloc; i < new_alloc; i++) 1019 sockets[i].type = AUTH_UNUSED; 1020 sockets_alloc = new_alloc; 1021 sockets[old_alloc].fd = fd; 1022 if ((sockets[old_alloc].input = sshbuf_new()) == NULL) 1023 fatal("%s: sshbuf_new failed", __func__); 1024 if ((sockets[old_alloc].output = sshbuf_new()) == NULL) 1025 fatal("%s: sshbuf_new failed", __func__); 1026 if ((sockets[old_alloc].request = sshbuf_new()) == NULL) 1027 fatal("%s: sshbuf_new failed", __func__); 1028 sockets[old_alloc].type = type; 1029 } 1030 1031 static int 1032 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp, 1033 struct timeval **tvpp) 1034 { 1035 u_int i, sz; 1036 int n = 0; 1037 static struct timeval tv; 1038 time_t deadline; 1039 1040 for (i = 0; i < sockets_alloc; i++) { 1041 switch (sockets[i].type) { 1042 case AUTH_SOCKET: 1043 case AUTH_CONNECTION: 1044 n = MAXIMUM(n, sockets[i].fd); 1045 break; 1046 case AUTH_UNUSED: 1047 break; 1048 default: 1049 fatal("Unknown socket type %d", sockets[i].type); 1050 break; 1051 } 1052 } 1053 1054 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 1055 if (*fdrp == NULL || sz > *nallocp) { 1056 free(*fdrp); 1057 free(*fdwp); 1058 *fdrp = xmalloc(sz); 1059 *fdwp = xmalloc(sz); 1060 *nallocp = sz; 1061 } 1062 if (n < *fdl) 1063 debug("XXX shrink: %d < %d", n, *fdl); 1064 *fdl = n; 1065 memset(*fdrp, 0, sz); 1066 memset(*fdwp, 0, sz); 1067 1068 for (i = 0; i < sockets_alloc; i++) { 1069 switch (sockets[i].type) { 1070 case AUTH_SOCKET: 1071 case AUTH_CONNECTION: 1072 FD_SET(sockets[i].fd, *fdrp); 1073 if (sshbuf_len(sockets[i].output) > 0) 1074 FD_SET(sockets[i].fd, *fdwp); 1075 break; 1076 default: 1077 break; 1078 } 1079 } 1080 deadline = reaper(); 1081 if (parent_alive_interval != 0) 1082 deadline = (deadline == 0) ? parent_alive_interval : 1083 MINIMUM(deadline, parent_alive_interval); 1084 if (deadline == 0) { 1085 *tvpp = NULL; 1086 } else { 1087 tv.tv_sec = deadline; 1088 tv.tv_usec = 0; 1089 *tvpp = &tv; 1090 } 1091 return (1); 1092 } 1093 1094 static void 1095 after_select(fd_set *readset, fd_set *writeset) 1096 { 1097 struct sockaddr_un sunaddr; 1098 socklen_t slen; 1099 char buf[1024]; 1100 int len, sock, r; 1101 u_int i, orig_alloc; 1102 uid_t euid; 1103 gid_t egid; 1104 1105 for (i = 0, orig_alloc = sockets_alloc; i < orig_alloc; i++) 1106 switch (sockets[i].type) { 1107 case AUTH_UNUSED: 1108 break; 1109 case AUTH_SOCKET: 1110 if (FD_ISSET(sockets[i].fd, readset)) { 1111 slen = sizeof(sunaddr); 1112 sock = accept(sockets[i].fd, 1113 (struct sockaddr *)&sunaddr, &slen); 1114 if (sock < 0) { 1115 error("accept from AUTH_SOCKET: %s", 1116 strerror(errno)); 1117 break; 1118 } 1119 if (getpeereid(sock, &euid, &egid) < 0) { 1120 error("getpeereid %d failed: %s", 1121 sock, strerror(errno)); 1122 close(sock); 1123 break; 1124 } 1125 if ((euid != 0) && (getuid() != euid)) { 1126 error("uid mismatch: " 1127 "peer euid %u != uid %u", 1128 (u_int) euid, (u_int) getuid()); 1129 close(sock); 1130 break; 1131 } 1132 new_socket(AUTH_CONNECTION, sock); 1133 } 1134 break; 1135 case AUTH_CONNECTION: 1136 if (sshbuf_len(sockets[i].output) > 0 && 1137 FD_ISSET(sockets[i].fd, writeset)) { 1138 len = write(sockets[i].fd, 1139 sshbuf_ptr(sockets[i].output), 1140 sshbuf_len(sockets[i].output)); 1141 if (len == -1 && (errno == EAGAIN || 1142 errno == EWOULDBLOCK || 1143 errno == EINTR)) 1144 continue; 1145 if (len <= 0) { 1146 close_socket(&sockets[i]); 1147 break; 1148 } 1149 if ((r = sshbuf_consume(sockets[i].output, 1150 len)) != 0) 1151 fatal("%s: buffer error: %s", 1152 __func__, ssh_err(r)); 1153 } 1154 if (FD_ISSET(sockets[i].fd, readset)) { 1155 len = read(sockets[i].fd, buf, sizeof(buf)); 1156 if (len == -1 && (errno == EAGAIN || 1157 errno == EWOULDBLOCK || 1158 errno == EINTR)) 1159 continue; 1160 if (len <= 0) { 1161 close_socket(&sockets[i]); 1162 break; 1163 } 1164 if ((r = sshbuf_put(sockets[i].input, 1165 buf, len)) != 0) 1166 fatal("%s: buffer error: %s", 1167 __func__, ssh_err(r)); 1168 explicit_bzero(buf, sizeof(buf)); 1169 process_message(&sockets[i]); 1170 } 1171 break; 1172 default: 1173 fatal("Unknown type %d", sockets[i].type); 1174 } 1175 } 1176 1177 static void 1178 cleanup_socket(void) 1179 { 1180 if (cleanup_pid != 0 && getpid() != cleanup_pid) 1181 return; 1182 debug("%s: cleanup", __func__); 1183 if (socket_name[0]) 1184 unlink(socket_name); 1185 if (socket_dir[0]) 1186 rmdir(socket_dir); 1187 } 1188 1189 void 1190 cleanup_exit(int i) 1191 { 1192 cleanup_socket(); 1193 _exit(i); 1194 } 1195 1196 /*ARGSUSED*/ 1197 static void 1198 cleanup_handler(int sig) 1199 { 1200 cleanup_socket(); 1201 #ifdef ENABLE_PKCS11 1202 pkcs11_terminate(); 1203 #endif 1204 _exit(2); 1205 } 1206 1207 static void 1208 check_parent_exists(void) 1209 { 1210 /* 1211 * If our parent has exited then getppid() will return (pid_t)1, 1212 * so testing for that should be safe. 1213 */ 1214 if (parent_pid != -1 && getppid() != parent_pid) { 1215 /* printf("Parent has died - Authentication agent exiting.\n"); */ 1216 cleanup_socket(); 1217 _exit(2); 1218 } 1219 } 1220 1221 static void 1222 usage(void) 1223 { 1224 fprintf(stderr, 1225 "usage: ssh-agent [-c | -s] [-Ddx] [-a bind_address] [-E fingerprint_hash]\n" 1226 " [-P pkcs11_whitelist] [-t life] [command [arg ...]]\n" 1227 " ssh-agent [-c | -s] -k\n"); 1228 exit(1); 1229 } 1230 1231 int 1232 main(int ac, char **av) 1233 { 1234 int c_flag = 0, d_flag = 0, D_flag = 0, k_flag = 0, s_flag = 0; 1235 int sock, fd, ch, result, saved_errno; 1236 u_int nalloc; 1237 char *shell, *format, *pidstr, *agentsocket = NULL; 1238 fd_set *readsetp = NULL, *writesetp = NULL; 1239 #ifdef HAVE_SETRLIMIT 1240 struct rlimit rlim; 1241 #endif 1242 extern int optind; 1243 extern char *optarg; 1244 pid_t pid; 1245 char pidstrbuf[1 + 3 * sizeof pid]; 1246 struct timeval *tvp = NULL; 1247 size_t len; 1248 mode_t prev_mask; 1249 1250 ssh_malloc_init(); /* must be called before any mallocs */ 1251 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1252 sanitise_stdfd(); 1253 1254 /* drop */ 1255 setegid(getgid()); 1256 setgid(getgid()); 1257 setuid(geteuid()); 1258 1259 platform_disable_tracing(0); /* strict=no */ 1260 1261 #ifdef WITH_OPENSSL 1262 OpenSSL_add_all_algorithms(); 1263 #endif 1264 1265 __progname = ssh_get_progname(av[0]); 1266 seed_rng(); 1267 1268 while ((ch = getopt(ac, av, "cDdksE:a:P:t:x")) != -1) { 1269 switch (ch) { 1270 case 'E': 1271 fingerprint_hash = ssh_digest_alg_by_name(optarg); 1272 if (fingerprint_hash == -1) 1273 fatal("Invalid hash algorithm \"%s\"", optarg); 1274 break; 1275 case 'c': 1276 if (s_flag) 1277 usage(); 1278 c_flag++; 1279 break; 1280 case 'k': 1281 k_flag++; 1282 break; 1283 case 'P': 1284 if (pkcs11_whitelist != NULL) 1285 fatal("-P option already specified"); 1286 pkcs11_whitelist = xstrdup(optarg); 1287 break; 1288 case 's': 1289 if (c_flag) 1290 usage(); 1291 s_flag++; 1292 break; 1293 case 'd': 1294 if (d_flag || D_flag) 1295 usage(); 1296 d_flag++; 1297 break; 1298 case 'D': 1299 if (d_flag || D_flag) 1300 usage(); 1301 D_flag++; 1302 break; 1303 case 'a': 1304 agentsocket = optarg; 1305 break; 1306 case 't': 1307 if ((lifetime = convtime(optarg)) == -1) { 1308 fprintf(stderr, "Invalid lifetime\n"); 1309 usage(); 1310 } 1311 break; 1312 case 'x': 1313 xcount = 0; 1314 break; 1315 default: 1316 usage(); 1317 } 1318 } 1319 ac -= optind; 1320 av += optind; 1321 1322 if (ac > 0 && (c_flag || k_flag || s_flag || d_flag || D_flag)) 1323 usage(); 1324 1325 if (pkcs11_whitelist == NULL) 1326 pkcs11_whitelist = xstrdup(DEFAULT_PKCS11_WHITELIST); 1327 1328 if (ac == 0 && !c_flag && !s_flag) { 1329 shell = getenv("SHELL"); 1330 if (shell != NULL && (len = strlen(shell)) > 2 && 1331 strncmp(shell + len - 3, "csh", 3) == 0) 1332 c_flag = 1; 1333 } 1334 if (k_flag) { 1335 const char *errstr = NULL; 1336 1337 pidstr = getenv(SSH_AGENTPID_ENV_NAME); 1338 if (pidstr == NULL) { 1339 fprintf(stderr, "%s not set, cannot kill agent\n", 1340 SSH_AGENTPID_ENV_NAME); 1341 exit(1); 1342 } 1343 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr); 1344 if (errstr) { 1345 fprintf(stderr, 1346 "%s=\"%s\", which is not a good PID: %s\n", 1347 SSH_AGENTPID_ENV_NAME, pidstr, errstr); 1348 exit(1); 1349 } 1350 if (kill(pid, SIGTERM) == -1) { 1351 perror("kill"); 1352 exit(1); 1353 } 1354 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; 1355 printf(format, SSH_AUTHSOCKET_ENV_NAME); 1356 printf(format, SSH_AGENTPID_ENV_NAME); 1357 printf("echo Agent pid %ld killed;\n", (long)pid); 1358 exit(0); 1359 } 1360 parent_pid = getpid(); 1361 1362 if (agentsocket == NULL) { 1363 /* Create private directory for agent socket */ 1364 mktemp_proto(socket_dir, sizeof(socket_dir)); 1365 if (mkdtemp(socket_dir) == NULL) { 1366 perror("mkdtemp: private socket dir"); 1367 exit(1); 1368 } 1369 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir, 1370 (long)parent_pid); 1371 } else { 1372 /* Try to use specified agent socket */ 1373 socket_dir[0] = '\0'; 1374 strlcpy(socket_name, agentsocket, sizeof socket_name); 1375 } 1376 1377 /* 1378 * Create socket early so it will exist before command gets run from 1379 * the parent. 1380 */ 1381 prev_mask = umask(0177); 1382 sock = unix_listener(socket_name, SSH_LISTEN_BACKLOG, 0); 1383 if (sock < 0) { 1384 /* XXX - unix_listener() calls error() not perror() */ 1385 *socket_name = '\0'; /* Don't unlink any existing file */ 1386 cleanup_exit(1); 1387 } 1388 umask(prev_mask); 1389 1390 /* 1391 * Fork, and have the parent execute the command, if any, or present 1392 * the socket data. The child continues as the authentication agent. 1393 */ 1394 if (D_flag || d_flag) { 1395 log_init(__progname, 1396 d_flag ? SYSLOG_LEVEL_DEBUG3 : SYSLOG_LEVEL_INFO, 1397 SYSLOG_FACILITY_AUTH, 1); 1398 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1399 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1400 SSH_AUTHSOCKET_ENV_NAME); 1401 printf("echo Agent pid %ld;\n", (long)parent_pid); 1402 fflush(stdout); 1403 goto skip; 1404 } 1405 pid = fork(); 1406 if (pid == -1) { 1407 perror("fork"); 1408 cleanup_exit(1); 1409 } 1410 if (pid != 0) { /* Parent - execute the given command. */ 1411 close(sock); 1412 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid); 1413 if (ac == 0) { 1414 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; 1415 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, 1416 SSH_AUTHSOCKET_ENV_NAME); 1417 printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, 1418 SSH_AGENTPID_ENV_NAME); 1419 printf("echo Agent pid %ld;\n", (long)pid); 1420 exit(0); 1421 } 1422 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || 1423 setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { 1424 perror("setenv"); 1425 exit(1); 1426 } 1427 execvp(av[0], av); 1428 perror(av[0]); 1429 exit(1); 1430 } 1431 /* child */ 1432 log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); 1433 1434 if (setsid() == -1) { 1435 error("setsid: %s", strerror(errno)); 1436 cleanup_exit(1); 1437 } 1438 1439 (void)chdir("/"); 1440 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1441 /* XXX might close listen socket */ 1442 (void)dup2(fd, STDIN_FILENO); 1443 (void)dup2(fd, STDOUT_FILENO); 1444 (void)dup2(fd, STDERR_FILENO); 1445 if (fd > 2) 1446 close(fd); 1447 } 1448 1449 #ifdef HAVE_SETRLIMIT 1450 /* deny core dumps, since memory contains unencrypted private keys */ 1451 rlim.rlim_cur = rlim.rlim_max = 0; 1452 if (setrlimit(RLIMIT_CORE, &rlim) < 0) { 1453 error("setrlimit RLIMIT_CORE: %s", strerror(errno)); 1454 cleanup_exit(1); 1455 } 1456 #endif 1457 1458 skip: 1459 1460 cleanup_pid = getpid(); 1461 1462 #ifdef ENABLE_PKCS11 1463 pkcs11_init(0); 1464 #endif 1465 new_socket(AUTH_SOCKET, sock); 1466 if (ac > 0) 1467 parent_alive_interval = 10; 1468 idtab_init(); 1469 signal(SIGPIPE, SIG_IGN); 1470 signal(SIGINT, (d_flag | D_flag) ? cleanup_handler : SIG_IGN); 1471 signal(SIGHUP, cleanup_handler); 1472 signal(SIGTERM, cleanup_handler); 1473 nalloc = 0; 1474 1475 if (pledge("stdio rpath cpath unix id proc exec", NULL) == -1) 1476 fatal("%s: pledge: %s", __progname, strerror(errno)); 1477 platform_pledge_agent(); 1478 1479 while (1) { 1480 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp); 1481 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp); 1482 saved_errno = errno; 1483 if (parent_alive_interval != 0) 1484 check_parent_exists(); 1485 (void) reaper(); /* remove expired keys */ 1486 if (result < 0) { 1487 if (saved_errno == EINTR) 1488 continue; 1489 fatal("select: %s", strerror(saved_errno)); 1490 } else if (result > 0) 1491 after_select(readsetp, writesetp); 1492 } 1493 /* NOTREACHED */ 1494 } 1495