ssh-agent.c revision 311915
1/* $OpenBSD: ssh-agent.c,v 1.212 2016/02/15 09:47:49 dtucker 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: stable/11/crypto/openssh/ssh-agent.c 311915 2017-01-11 05:56:40Z delphij $"); 39 40#include <sys/param.h> /* MIN MAX */ 41#include <sys/types.h> 42#include <sys/param.h> 43#include <sys/resource.h> 44#include <sys/stat.h> 45#include <sys/socket.h> 46#ifdef HAVE_SYS_TIME_H 47# include <sys/time.h> 48#endif 49#ifdef HAVE_SYS_UN_H 50# include <sys/un.h> 51#endif 52#include "openbsd-compat/sys-queue.h" 53 54#ifdef WITH_OPENSSL 55#include <openssl/evp.h> 56#include "openbsd-compat/openssl-compat.h" 57#endif 58 59#include <errno.h> 60#include <fcntl.h> 61#include <limits.h> 62#ifdef HAVE_PATHS_H 63# include <paths.h> 64#endif 65#include <signal.h> 66#include <stdarg.h> 67#include <stdio.h> 68#include <stdlib.h> 69#include <time.h> 70#include <string.h> 71#include <unistd.h> 72#ifdef HAVE_UTIL_H 73# include <util.h> 74#endif 75 76#include "xmalloc.h" 77#include "ssh.h" 78#include "rsa.h" 79#include "sshbuf.h" 80#include "sshkey.h" 81#include "authfd.h" 82#include "compat.h" 83#include "log.h" 84#include "misc.h" 85#include "digest.h" 86#include "ssherr.h" 87#include "match.h" 88 89#ifdef ENABLE_PKCS11 90#include "ssh-pkcs11.h" 91#endif 92 93#ifndef DEFAULT_PKCS11_WHITELIST 94# define DEFAULT_PKCS11_WHITELIST "/usr/lib/*,/usr/local/lib/*" 95#endif 96 97#if defined(HAVE_SYS_PRCTL_H) 98#include <sys/prctl.h> /* For prctl() and PR_SET_DUMPABLE */ 99#endif 100 101typedef enum { 102 AUTH_UNUSED, 103 AUTH_SOCKET, 104 AUTH_CONNECTION 105} sock_type; 106 107typedef struct { 108 int fd; 109 sock_type type; 110 struct sshbuf *input; 111 struct sshbuf *output; 112 struct sshbuf *request; 113} SocketEntry; 114 115u_int sockets_alloc = 0; 116SocketEntry *sockets = NULL; 117 118typedef struct identity { 119 TAILQ_ENTRY(identity) next; 120 struct sshkey *key; 121 char *comment; 122 char *provider; 123 time_t death; 124 u_int confirm; 125} Identity; 126 127typedef struct { 128 int nentries; 129 TAILQ_HEAD(idqueue, identity) idlist; 130} Idtab; 131 132/* private key table, one per protocol version */ 133Idtab idtable[3]; 134 135int max_fd = 0; 136 137/* pid of shell == parent of agent */ 138pid_t parent_pid = -1; 139time_t parent_alive_interval = 0; 140 141/* pid of process for which cleanup_socket is applicable */ 142pid_t cleanup_pid = 0; 143 144/* pathname and directory for AUTH_SOCKET */ 145char socket_name[PATH_MAX]; 146char socket_dir[PATH_MAX]; 147 148/* PKCS#11 path whitelist */ 149static char *pkcs11_whitelist; 150 151/* locking */ 152#define LOCK_SIZE 32 153#define LOCK_SALT_SIZE 16 154#define LOCK_ROUNDS 1 155int locked = 0; 156char lock_passwd[LOCK_SIZE]; 157char lock_salt[LOCK_SALT_SIZE]; 158 159extern char *__progname; 160 161/* Default lifetime in seconds (0 == forever) */ 162static long lifetime = 0; 163 164static int fingerprint_hash = SSH_FP_HASH_DEFAULT; 165 166/* 167 * Client connection count; incremented in new_socket() and decremented in 168 * close_socket(). When it reaches 0, ssh-agent will exit. Since it is 169 * normally initialized to 1, it will never reach 0. However, if the -x 170 * option is specified, it is initialized to 0 in main(); in that case, 171 * ssh-agent will exit as soon as it has had at least one client but no 172 * longer has any. 173 */ 174static int xcount = 1; 175 176static void 177close_socket(SocketEntry *e) 178{ 179 int last = 0; 180 181 if (e->type == AUTH_CONNECTION) { 182 debug("xcount %d -> %d", xcount, xcount - 1); 183 if (--xcount == 0) 184 last = 1; 185 } 186 close(e->fd); 187 e->fd = -1; 188 e->type = AUTH_UNUSED; 189 sshbuf_free(e->input); 190 sshbuf_free(e->output); 191 sshbuf_free(e->request); 192 if (last) 193 cleanup_exit(0); 194} 195 196static void 197idtab_init(void) 198{ 199 int i; 200 201 for (i = 0; i <=2; i++) { 202 TAILQ_INIT(&idtable[i].idlist); 203 idtable[i].nentries = 0; 204 } 205} 206 207/* return private key table for requested protocol version */ 208static Idtab * 209idtab_lookup(int version) 210{ 211 if (version < 1 || version > 2) 212 fatal("internal error, bad protocol version %d", version); 213 return &idtable[version]; 214} 215 216static void 217free_identity(Identity *id) 218{ 219 sshkey_free(id->key); 220 free(id->provider); 221 free(id->comment); 222 free(id); 223} 224 225/* return matching private key for given public key */ 226static Identity * 227lookup_identity(struct sshkey *key, int version) 228{ 229 Identity *id; 230 231 Idtab *tab = idtab_lookup(version); 232 TAILQ_FOREACH(id, &tab->idlist, next) { 233 if (sshkey_equal(key, id->key)) 234 return (id); 235 } 236 return (NULL); 237} 238 239/* Check confirmation of keysign request */ 240static int 241confirm_key(Identity *id) 242{ 243 char *p; 244 int ret = -1; 245 246 p = sshkey_fingerprint(id->key, fingerprint_hash, SSH_FP_DEFAULT); 247 if (p != NULL && 248 ask_permission("Allow use of key %s?\nKey fingerprint %s.", 249 id->comment, p)) 250 ret = 0; 251 free(p); 252 253 return (ret); 254} 255 256static void 257send_status(SocketEntry *e, int success) 258{ 259 int r; 260 261 if ((r = sshbuf_put_u32(e->output, 1)) != 0 || 262 (r = sshbuf_put_u8(e->output, success ? 263 SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0) 264 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 265} 266 267/* send list of supported public keys to 'client' */ 268static void 269process_request_identities(SocketEntry *e, int version) 270{ 271 Idtab *tab = idtab_lookup(version); 272 Identity *id; 273 struct sshbuf *msg; 274 int r; 275 276 if ((msg = sshbuf_new()) == NULL) 277 fatal("%s: sshbuf_new failed", __func__); 278 if ((r = sshbuf_put_u8(msg, (version == 1) ? 279 SSH_AGENT_RSA_IDENTITIES_ANSWER : 280 SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 281 (r = sshbuf_put_u32(msg, tab->nentries)) != 0) 282 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 283 TAILQ_FOREACH(id, &tab->idlist, next) { 284 if (id->key->type == KEY_RSA1) { 285#ifdef WITH_SSH1 286 if ((r = sshbuf_put_u32(msg, 287 BN_num_bits(id->key->rsa->n))) != 0 || 288 (r = sshbuf_put_bignum1(msg, 289 id->key->rsa->e)) != 0 || 290 (r = sshbuf_put_bignum1(msg, 291 id->key->rsa->n)) != 0) 292 fatal("%s: buffer error: %s", 293 __func__, ssh_err(r)); 294#endif 295 } else { 296 u_char *blob; 297 size_t blen; 298 299 if ((r = sshkey_to_blob(id->key, &blob, &blen)) != 0) { 300 error("%s: sshkey_to_blob: %s", __func__, 301 ssh_err(r)); 302 continue; 303 } 304 if ((r = sshbuf_put_string(msg, blob, blen)) != 0) 305 fatal("%s: buffer error: %s", 306 __func__, ssh_err(r)); 307 free(blob); 308 } 309 if ((r = sshbuf_put_cstring(msg, id->comment)) != 0) 310 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 311 } 312 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 313 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 314 sshbuf_free(msg); 315} 316 317#ifdef WITH_SSH1 318/* ssh1 only */ 319static void 320process_authentication_challenge1(SocketEntry *e) 321{ 322 u_char buf[32], mdbuf[16], session_id[16]; 323 u_int response_type; 324 BIGNUM *challenge; 325 Identity *id; 326 int r, len; 327 struct sshbuf *msg; 328 struct ssh_digest_ctx *md; 329 struct sshkey *key; 330 331 if ((msg = sshbuf_new()) == NULL) 332 fatal("%s: sshbuf_new failed", __func__); 333 if ((key = sshkey_new(KEY_RSA1)) == NULL) 334 fatal("%s: sshkey_new failed", __func__); 335 if ((challenge = BN_new()) == NULL) 336 fatal("%s: BN_new failed", __func__); 337 338 if ((r = sshbuf_get_u32(e->request, NULL)) != 0 || /* ignored */ 339 (r = sshbuf_get_bignum1(e->request, key->rsa->e)) != 0 || 340 (r = sshbuf_get_bignum1(e->request, key->rsa->n)) != 0 || 341 (r = sshbuf_get_bignum1(e->request, challenge))) 342 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 343 344 /* Only protocol 1.1 is supported */ 345 if (sshbuf_len(e->request) == 0) 346 goto failure; 347 if ((r = sshbuf_get(e->request, session_id, sizeof(session_id))) != 0 || 348 (r = sshbuf_get_u32(e->request, &response_type)) != 0) 349 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 350 if (response_type != 1) 351 goto failure; 352 353 id = lookup_identity(key, 1); 354 if (id != NULL && (!id->confirm || confirm_key(id) == 0)) { 355 struct sshkey *private = id->key; 356 /* Decrypt the challenge using the private key. */ 357 if ((r = rsa_private_decrypt(challenge, challenge, 358 private->rsa) != 0)) { 359 fatal("%s: rsa_public_encrypt: %s", __func__, 360 ssh_err(r)); 361 goto failure; /* XXX ? */ 362 } 363 364 /* The response is MD5 of decrypted challenge plus session id */ 365 len = BN_num_bytes(challenge); 366 if (len <= 0 || len > 32) { 367 logit("%s: bad challenge length %d", __func__, len); 368 goto failure; 369 } 370 memset(buf, 0, 32); 371 BN_bn2bin(challenge, buf + 32 - len); 372 if ((md = ssh_digest_start(SSH_DIGEST_MD5)) == NULL || 373 ssh_digest_update(md, buf, 32) < 0 || 374 ssh_digest_update(md, session_id, 16) < 0 || 375 ssh_digest_final(md, mdbuf, sizeof(mdbuf)) < 0) 376 fatal("%s: md5 failed", __func__); 377 ssh_digest_free(md); 378 379 /* Send the response. */ 380 if ((r = sshbuf_put_u8(msg, SSH_AGENT_RSA_RESPONSE)) != 0 || 381 (r = sshbuf_put(msg, mdbuf, sizeof(mdbuf))) != 0) 382 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 383 goto send; 384 } 385 386 failure: 387 /* Unknown identity or protocol error. Send failure. */ 388 if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0) 389 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 390 send: 391 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 392 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 393 sshkey_free(key); 394 BN_clear_free(challenge); 395 sshbuf_free(msg); 396} 397#endif 398 399static char * 400agent_decode_alg(struct sshkey *key, u_int flags) 401{ 402 if (key->type == KEY_RSA) { 403 if (flags & SSH_AGENT_RSA_SHA2_256) 404 return "rsa-sha2-256"; 405 else if (flags & SSH_AGENT_RSA_SHA2_512) 406 return "rsa-sha2-512"; 407 } 408 return NULL; 409} 410 411/* ssh2 only */ 412static void 413process_sign_request2(SocketEntry *e) 414{ 415 u_char *blob, *data, *signature = NULL; 416 size_t blen, dlen, slen = 0; 417 u_int compat = 0, flags; 418 int r, ok = -1; 419 struct sshbuf *msg; 420 struct sshkey *key; 421 struct identity *id; 422 423 if ((msg = sshbuf_new()) == NULL) 424 fatal("%s: sshbuf_new failed", __func__); 425 if ((r = sshbuf_get_string(e->request, &blob, &blen)) != 0 || 426 (r = sshbuf_get_string(e->request, &data, &dlen)) != 0 || 427 (r = sshbuf_get_u32(e->request, &flags)) != 0) 428 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 429 if (flags & SSH_AGENT_OLD_SIGNATURE) 430 compat = SSH_BUG_SIGBLOB; 431 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) { 432 error("%s: cannot parse key blob: %s", __func__, ssh_err(r)); 433 goto send; 434 } 435 if ((id = lookup_identity(key, 2)) == NULL) { 436 verbose("%s: %s key not found", __func__, sshkey_type(key)); 437 goto send; 438 } 439 if (id->confirm && confirm_key(id) != 0) { 440 verbose("%s: user refused key", __func__); 441 goto send; 442 } 443 if ((r = sshkey_sign(id->key, &signature, &slen, 444 data, dlen, agent_decode_alg(key, flags), compat)) != 0) { 445 error("%s: sshkey_sign: %s", __func__, ssh_err(r)); 446 goto send; 447 } 448 /* Success */ 449 ok = 0; 450 send: 451 sshkey_free(key); 452 if (ok == 0) { 453 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 || 454 (r = sshbuf_put_string(msg, signature, slen)) != 0) 455 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 456 } else if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0) 457 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 458 459 if ((r = sshbuf_put_stringb(e->output, msg)) != 0) 460 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 461 462 sshbuf_free(msg); 463 free(data); 464 free(blob); 465 free(signature); 466} 467 468/* shared */ 469static void 470process_remove_identity(SocketEntry *e, int version) 471{ 472 size_t blen; 473 int r, success = 0; 474 struct sshkey *key = NULL; 475 u_char *blob; 476#ifdef WITH_SSH1 477 u_int bits; 478#endif /* WITH_SSH1 */ 479 480 switch (version) { 481#ifdef WITH_SSH1 482 case 1: 483 if ((key = sshkey_new(KEY_RSA1)) == NULL) { 484 error("%s: sshkey_new failed", __func__); 485 return; 486 } 487 if ((r = sshbuf_get_u32(e->request, &bits)) != 0 || 488 (r = sshbuf_get_bignum1(e->request, key->rsa->e)) != 0 || 489 (r = sshbuf_get_bignum1(e->request, key->rsa->n)) != 0) 490 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 491 492 if (bits != sshkey_size(key)) 493 logit("Warning: identity keysize mismatch: " 494 "actual %u, announced %u", 495 sshkey_size(key), bits); 496 break; 497#endif /* WITH_SSH1 */ 498 case 2: 499 if ((r = sshbuf_get_string(e->request, &blob, &blen)) != 0) 500 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 501 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) 502 error("%s: sshkey_from_blob failed: %s", 503 __func__, ssh_err(r)); 504 free(blob); 505 break; 506 } 507 if (key != NULL) { 508 Identity *id = lookup_identity(key, version); 509 if (id != NULL) { 510 /* 511 * We have this key. Free the old key. Since we 512 * don't want to leave empty slots in the middle of 513 * the array, we actually free the key there and move 514 * all the entries between the empty slot and the end 515 * of the array. 516 */ 517 Idtab *tab = idtab_lookup(version); 518 if (tab->nentries < 1) 519 fatal("process_remove_identity: " 520 "internal error: tab->nentries %d", 521 tab->nentries); 522 TAILQ_REMOVE(&tab->idlist, id, next); 523 free_identity(id); 524 tab->nentries--; 525 success = 1; 526 } 527 sshkey_free(key); 528 } 529 send_status(e, success); 530} 531 532static void 533process_remove_all_identities(SocketEntry *e, int version) 534{ 535 Idtab *tab = idtab_lookup(version); 536 Identity *id; 537 538 /* Loop over all identities and clear the keys. */ 539 for (id = TAILQ_FIRST(&tab->idlist); id; 540 id = TAILQ_FIRST(&tab->idlist)) { 541 TAILQ_REMOVE(&tab->idlist, id, next); 542 free_identity(id); 543 } 544 545 /* Mark that there are no identities. */ 546 tab->nentries = 0; 547 548 /* Send success. */ 549 send_status(e, 1); 550} 551 552/* removes expired keys and returns number of seconds until the next expiry */ 553static time_t 554reaper(void) 555{ 556 time_t deadline = 0, now = monotime(); 557 Identity *id, *nxt; 558 int version; 559 Idtab *tab; 560 561 for (version = 1; version < 3; version++) { 562 tab = idtab_lookup(version); 563 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 564 nxt = TAILQ_NEXT(id, next); 565 if (id->death == 0) 566 continue; 567 if (now >= id->death) { 568 debug("expiring key '%s'", id->comment); 569 TAILQ_REMOVE(&tab->idlist, id, next); 570 free_identity(id); 571 tab->nentries--; 572 } else 573 deadline = (deadline == 0) ? id->death : 574 MIN(deadline, id->death); 575 } 576 } 577 if (deadline == 0 || deadline <= now) 578 return 0; 579 else 580 return (deadline - now); 581} 582 583/* 584 * XXX this and the corresponding serialisation function probably belongs 585 * in key.c 586 */ 587#ifdef WITH_SSH1 588static int 589agent_decode_rsa1(struct sshbuf *m, struct sshkey **kp) 590{ 591 struct sshkey *k = NULL; 592 int r = SSH_ERR_INTERNAL_ERROR; 593 594 *kp = NULL; 595 if ((k = sshkey_new_private(KEY_RSA1)) == NULL) 596 return SSH_ERR_ALLOC_FAIL; 597 598 if ((r = sshbuf_get_u32(m, NULL)) != 0 || /* ignored */ 599 (r = sshbuf_get_bignum1(m, k->rsa->n)) != 0 || 600 (r = sshbuf_get_bignum1(m, k->rsa->e)) != 0 || 601 (r = sshbuf_get_bignum1(m, k->rsa->d)) != 0 || 602 (r = sshbuf_get_bignum1(m, k->rsa->iqmp)) != 0 || 603 /* SSH1 and SSL have p and q swapped */ 604 (r = sshbuf_get_bignum1(m, k->rsa->q)) != 0 || /* p */ 605 (r = sshbuf_get_bignum1(m, k->rsa->p)) != 0) /* q */ 606 goto out; 607 608 /* Generate additional parameters */ 609 if ((r = rsa_generate_additional_parameters(k->rsa)) != 0) 610 goto out; 611 /* enable blinding */ 612 if (RSA_blinding_on(k->rsa, NULL) != 1) { 613 r = SSH_ERR_LIBCRYPTO_ERROR; 614 goto out; 615 } 616 617 r = 0; /* success */ 618 out: 619 if (r == 0) 620 *kp = k; 621 else 622 sshkey_free(k); 623 return r; 624} 625#endif /* WITH_SSH1 */ 626 627static void 628process_add_identity(SocketEntry *e, int version) 629{ 630 Idtab *tab = idtab_lookup(version); 631 Identity *id; 632 int success = 0, confirm = 0; 633 u_int seconds; 634 char *comment = NULL; 635 time_t death = 0; 636 struct sshkey *k = NULL; 637 u_char ctype; 638 int r = SSH_ERR_INTERNAL_ERROR; 639 640 switch (version) { 641#ifdef WITH_SSH1 642 case 1: 643 r = agent_decode_rsa1(e->request, &k); 644 break; 645#endif /* WITH_SSH1 */ 646 case 2: 647 r = sshkey_private_deserialize(e->request, &k); 648 break; 649 } 650 if (r != 0 || k == NULL || 651 (r = sshbuf_get_cstring(e->request, &comment, NULL)) != 0) { 652 error("%s: decode private key: %s", __func__, ssh_err(r)); 653 goto err; 654 } 655 656 while (sshbuf_len(e->request)) { 657 if ((r = sshbuf_get_u8(e->request, &ctype)) != 0) { 658 error("%s: buffer error: %s", __func__, ssh_err(r)); 659 goto err; 660 } 661 switch (ctype) { 662 case SSH_AGENT_CONSTRAIN_LIFETIME: 663 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) { 664 error("%s: bad lifetime constraint: %s", 665 __func__, ssh_err(r)); 666 goto err; 667 } 668 death = monotime() + seconds; 669 break; 670 case SSH_AGENT_CONSTRAIN_CONFIRM: 671 confirm = 1; 672 break; 673 default: 674 error("%s: Unknown constraint %d", __func__, ctype); 675 err: 676 sshbuf_reset(e->request); 677 free(comment); 678 sshkey_free(k); 679 goto send; 680 } 681 } 682 683 success = 1; 684 if (lifetime && !death) 685 death = monotime() + lifetime; 686 if ((id = lookup_identity(k, version)) == NULL) { 687 id = xcalloc(1, sizeof(Identity)); 688 id->key = k; 689 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 690 /* Increment the number of identities. */ 691 tab->nentries++; 692 } else { 693 sshkey_free(k); 694 free(id->comment); 695 } 696 id->comment = comment; 697 id->death = death; 698 id->confirm = confirm; 699send: 700 send_status(e, success); 701} 702 703/* XXX todo: encrypt sensitive data with passphrase */ 704static void 705process_lock_agent(SocketEntry *e, int lock) 706{ 707 int r, success = 0, delay; 708 char *passwd, passwdhash[LOCK_SIZE]; 709 static u_int fail_count = 0; 710 size_t pwlen; 711 712 if ((r = sshbuf_get_cstring(e->request, &passwd, &pwlen)) != 0) 713 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 714 if (pwlen == 0) { 715 debug("empty password not supported"); 716 } else if (locked && !lock) { 717 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 718 passwdhash, sizeof(passwdhash), LOCK_ROUNDS) < 0) 719 fatal("bcrypt_pbkdf"); 720 if (timingsafe_bcmp(passwdhash, lock_passwd, LOCK_SIZE) == 0) { 721 debug("agent unlocked"); 722 locked = 0; 723 fail_count = 0; 724 explicit_bzero(lock_passwd, sizeof(lock_passwd)); 725 success = 1; 726 } else { 727 /* delay in 0.1s increments up to 10s */ 728 if (fail_count < 100) 729 fail_count++; 730 delay = 100000 * fail_count; 731 debug("unlock failed, delaying %0.1lf seconds", 732 (double)delay/1000000); 733 usleep(delay); 734 } 735 explicit_bzero(passwdhash, sizeof(passwdhash)); 736 } else if (!locked && lock) { 737 debug("agent locked"); 738 locked = 1; 739 arc4random_buf(lock_salt, sizeof(lock_salt)); 740 if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt), 741 lock_passwd, sizeof(lock_passwd), LOCK_ROUNDS) < 0) 742 fatal("bcrypt_pbkdf"); 743 success = 1; 744 } 745 explicit_bzero(passwd, pwlen); 746 free(passwd); 747 send_status(e, success); 748} 749 750static void 751no_identities(SocketEntry *e, u_int type) 752{ 753 struct sshbuf *msg; 754 int r; 755 756 if ((msg = sshbuf_new()) == NULL) 757 fatal("%s: sshbuf_new failed", __func__); 758 if ((r = sshbuf_put_u8(msg, 759 (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ? 760 SSH_AGENT_RSA_IDENTITIES_ANSWER : 761 SSH2_AGENT_IDENTITIES_ANSWER)) != 0 || 762 (r = sshbuf_put_u32(msg, 0)) != 0 || 763 (r = sshbuf_put_stringb(e->output, msg)) != 0) 764 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 765 sshbuf_free(msg); 766} 767 768#ifdef ENABLE_PKCS11 769static void 770process_add_smartcard_key(SocketEntry *e) 771{ 772 char *provider = NULL, *pin, canonical_provider[PATH_MAX]; 773 int r, i, version, count = 0, success = 0, confirm = 0; 774 u_int seconds; 775 time_t death = 0; 776 u_char type; 777 struct sshkey **keys = NULL, *k; 778 Identity *id; 779 Idtab *tab; 780 781 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 782 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) 783 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 784 785 while (sshbuf_len(e->request)) { 786 if ((r = sshbuf_get_u8(e->request, &type)) != 0) 787 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 788 switch (type) { 789 case SSH_AGENT_CONSTRAIN_LIFETIME: 790 if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) 791 fatal("%s: buffer error: %s", 792 __func__, ssh_err(r)); 793 death = monotime() + seconds; 794 break; 795 case SSH_AGENT_CONSTRAIN_CONFIRM: 796 confirm = 1; 797 break; 798 default: 799 error("process_add_smartcard_key: " 800 "Unknown constraint type %d", type); 801 goto send; 802 } 803 } 804 if (realpath(provider, canonical_provider) == NULL) { 805 verbose("failed PKCS#11 add of \"%.100s\": realpath: %s", 806 provider, strerror(errno)); 807 goto send; 808 } 809 if (match_pattern_list(canonical_provider, pkcs11_whitelist, 0) != 1) { 810 verbose("refusing PKCS#11 add of \"%.100s\": " 811 "provider not whitelisted", canonical_provider); 812 goto send; 813 } 814 debug("%s: add %.100s", __func__, canonical_provider); 815 if (lifetime && !death) 816 death = monotime() + lifetime; 817 818 count = pkcs11_add_provider(canonical_provider, pin, &keys); 819 for (i = 0; i < count; i++) { 820 k = keys[i]; 821 version = k->type == KEY_RSA1 ? 1 : 2; 822 tab = idtab_lookup(version); 823 if (lookup_identity(k, version) == NULL) { 824 id = xcalloc(1, sizeof(Identity)); 825 id->key = k; 826 id->provider = xstrdup(canonical_provider); 827 id->comment = xstrdup(canonical_provider); /* XXX */ 828 id->death = death; 829 id->confirm = confirm; 830 TAILQ_INSERT_TAIL(&tab->idlist, id, next); 831 tab->nentries++; 832 success = 1; 833 } else { 834 sshkey_free(k); 835 } 836 keys[i] = NULL; 837 } 838send: 839 free(pin); 840 free(provider); 841 free(keys); 842 send_status(e, success); 843} 844 845static void 846process_remove_smartcard_key(SocketEntry *e) 847{ 848 char *provider = NULL, *pin = NULL; 849 int r, version, success = 0; 850 Identity *id, *nxt; 851 Idtab *tab; 852 853 if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 || 854 (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) 855 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 856 free(pin); 857 858 for (version = 1; version < 3; version++) { 859 tab = idtab_lookup(version); 860 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { 861 nxt = TAILQ_NEXT(id, next); 862 /* Skip file--based keys */ 863 if (id->provider == NULL) 864 continue; 865 if (!strcmp(provider, id->provider)) { 866 TAILQ_REMOVE(&tab->idlist, id, next); 867 free_identity(id); 868 tab->nentries--; 869 } 870 } 871 } 872 if (pkcs11_del_provider(provider) == 0) 873 success = 1; 874 else 875 error("process_remove_smartcard_key:" 876 " pkcs11_del_provider failed"); 877 free(provider); 878 send_status(e, success); 879} 880#endif /* ENABLE_PKCS11 */ 881 882/* dispatch incoming messages */ 883 884static void 885process_message(SocketEntry *e) 886{ 887 u_int msg_len; 888 u_char type; 889 const u_char *cp; 890 int r; 891 892 if (sshbuf_len(e->input) < 5) 893 return; /* Incomplete message. */ 894 cp = sshbuf_ptr(e->input); 895 msg_len = PEEK_U32(cp); 896 if (msg_len > 256 * 1024) { 897 close_socket(e); 898 return; 899 } 900 if (sshbuf_len(e->input) < msg_len + 4) 901 return; 902 903 /* move the current input to e->request */ 904 sshbuf_reset(e->request); 905 if ((r = sshbuf_get_stringb(e->input, e->request)) != 0 || 906 (r = sshbuf_get_u8(e->request, &type)) != 0) 907 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 908 909 /* check wheter agent is locked */ 910 if (locked && type != SSH_AGENTC_UNLOCK) { 911 sshbuf_reset(e->request); 912 switch (type) { 913 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 914 case SSH2_AGENTC_REQUEST_IDENTITIES: 915 /* send empty lists */ 916 no_identities(e, type); 917 break; 918 default: 919 /* send a fail message for all other request types */ 920 send_status(e, 0); 921 } 922 return; 923 } 924 925 debug("type %d", type); 926 switch (type) { 927 case SSH_AGENTC_LOCK: 928 case SSH_AGENTC_UNLOCK: 929 process_lock_agent(e, type == SSH_AGENTC_LOCK); 930 break; 931#ifdef WITH_SSH1 932 /* ssh1 */ 933 case SSH_AGENTC_RSA_CHALLENGE: 934 process_authentication_challenge1(e); 935 break; 936 case SSH_AGENTC_REQUEST_RSA_IDENTITIES: 937 process_request_identities(e, 1); 938 break; 939 case SSH_AGENTC_ADD_RSA_IDENTITY: 940 case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED: 941 process_add_identity(e, 1); 942 break; 943 case SSH_AGENTC_REMOVE_RSA_IDENTITY: 944 process_remove_identity(e, 1); 945 break; 946#endif 947 case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: 948 process_remove_all_identities(e, 1); /* safe for !WITH_SSH1 */ 949 break; 950 /* ssh2 */ 951 case SSH2_AGENTC_SIGN_REQUEST: 952 process_sign_request2(e); 953 break; 954 case SSH2_AGENTC_REQUEST_IDENTITIES: 955 process_request_identities(e, 2); 956 break; 957 case SSH2_AGENTC_ADD_IDENTITY: 958 case SSH2_AGENTC_ADD_ID_CONSTRAINED: 959 process_add_identity(e, 2); 960 break; 961 case SSH2_AGENTC_REMOVE_IDENTITY: 962 process_remove_identity(e, 2); 963 break; 964 case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: 965 process_remove_all_identities(e, 2); 966 break; 967#ifdef ENABLE_PKCS11 968 case SSH_AGENTC_ADD_SMARTCARD_KEY: 969 case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: 970 process_add_smartcard_key(e); 971 break; 972 case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 973 process_remove_smartcard_key(e); 974 break; 975#endif /* ENABLE_PKCS11 */ 976 default: 977 /* Unknown message. Respond with failure. */ 978 error("Unknown message %d", type); 979 sshbuf_reset(e->request); 980 send_status(e, 0); 981 break; 982 } 983} 984 985static void 986new_socket(sock_type type, int fd) 987{ 988 u_int i, old_alloc, new_alloc; 989 990 if (type == AUTH_CONNECTION) { 991 debug("xcount %d -> %d", xcount, xcount + 1); 992 ++xcount; 993 } 994 set_nonblock(fd); 995 996 if (fd > max_fd) 997 max_fd = fd; 998 999 for (i = 0; i < sockets_alloc; i++) 1000 if (sockets[i].type == AUTH_UNUSED) { 1001 sockets[i].fd = fd; 1002 if ((sockets[i].input = sshbuf_new()) == NULL) 1003 fatal("%s: sshbuf_new failed", __func__); 1004 if ((sockets[i].output = sshbuf_new()) == NULL) 1005 fatal("%s: sshbuf_new failed", __func__); 1006 if ((sockets[i].request = sshbuf_new()) == NULL) 1007 fatal("%s: sshbuf_new failed", __func__); 1008 sockets[i].type = type; 1009 return; 1010 } 1011 old_alloc = sockets_alloc; 1012 new_alloc = sockets_alloc + 10; 1013 sockets = xreallocarray(sockets, new_alloc, sizeof(sockets[0])); 1014 for (i = old_alloc; i < new_alloc; i++) 1015 sockets[i].type = AUTH_UNUSED; 1016 sockets_alloc = new_alloc; 1017 sockets[old_alloc].fd = fd; 1018 if ((sockets[old_alloc].input = sshbuf_new()) == NULL) 1019 fatal("%s: sshbuf_new failed", __func__); 1020 if ((sockets[old_alloc].output = sshbuf_new()) == NULL) 1021 fatal("%s: sshbuf_new failed", __func__); 1022 if ((sockets[old_alloc].request = sshbuf_new()) == NULL) 1023 fatal("%s: sshbuf_new failed", __func__); 1024 sockets[old_alloc].type = type; 1025} 1026 1027static int 1028prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp, 1029 struct timeval **tvpp) 1030{ 1031 u_int i, sz; 1032 int n = 0; 1033 static struct timeval tv; 1034 time_t deadline; 1035 1036 for (i = 0; i < sockets_alloc; i++) { 1037 switch (sockets[i].type) { 1038 case AUTH_SOCKET: 1039 case AUTH_CONNECTION: 1040 n = MAX(n, sockets[i].fd); 1041 break; 1042 case AUTH_UNUSED: 1043 break; 1044 default: 1045 fatal("Unknown socket type %d", sockets[i].type); 1046 break; 1047 } 1048 } 1049 1050 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 1051 if (*fdrp == NULL || sz > *nallocp) { 1052 free(*fdrp); 1053 free(*fdwp); 1054 *fdrp = xmalloc(sz); 1055 *fdwp = xmalloc(sz); 1056 *nallocp = sz; 1057 } 1058 if (n < *fdl) 1059 debug("XXX shrink: %d < %d", n, *fdl); 1060 *fdl = n; 1061 memset(*fdrp, 0, sz); 1062 memset(*fdwp, 0, sz); 1063 1064 for (i = 0; i < sockets_alloc; i++) { 1065 switch (sockets[i].type) { 1066 case AUTH_SOCKET: 1067 case AUTH_CONNECTION: 1068 FD_SET(sockets[i].fd, *fdrp); 1069 if (sshbuf_len(sockets[i].output) > 0) 1070 FD_SET(sockets[i].fd, *fdwp); 1071 break; 1072 default: 1073 break; 1074 } 1075 } 1076 deadline = reaper(); 1077 if (parent_alive_interval != 0) 1078 deadline = (deadline == 0) ? parent_alive_interval : 1079 MIN(deadline, parent_alive_interval); 1080 if (deadline == 0) { 1081 *tvpp = NULL; 1082 } else { 1083 tv.tv_sec = deadline; 1084 tv.tv_usec = 0; 1085 *tvpp = &tv; 1086 } 1087 return (1); 1088} 1089 1090static void 1091after_select(fd_set *readset, fd_set *writeset) 1092{ 1093 struct sockaddr_un sunaddr; 1094 socklen_t slen; 1095 char buf[1024]; 1096 int len, sock, r; 1097 u_int i, orig_alloc; 1098 uid_t euid; 1099 gid_t egid; 1100 1101 for (i = 0, orig_alloc = sockets_alloc; i < orig_alloc; i++) 1102 switch (sockets[i].type) { 1103 case AUTH_UNUSED: 1104 break; 1105 case AUTH_SOCKET: 1106 if (FD_ISSET(sockets[i].fd, readset)) { 1107 slen = sizeof(sunaddr); 1108 sock = accept(sockets[i].fd, 1109 (struct sockaddr *)&sunaddr, &slen); 1110 if (sock < 0) { 1111 error("accept from AUTH_SOCKET: %s", 1112 strerror(errno)); 1113 break; 1114 } 1115 if (getpeereid(sock, &euid, &egid) < 0) { 1116 error("getpeereid %d failed: %s", 1117 sock, strerror(errno)); 1118 close(sock); 1119 break; 1120 } 1121 if ((euid != 0) && (getuid() != euid)) { 1122 error("uid mismatch: " 1123 "peer euid %u != uid %u", 1124 (u_int) euid, (u_int) getuid()); 1125 close(sock); 1126 break; 1127 } 1128 new_socket(AUTH_CONNECTION, sock); 1129 } 1130 break; 1131 case AUTH_CONNECTION: 1132 if (sshbuf_len(sockets[i].output) > 0 && 1133 FD_ISSET(sockets[i].fd, writeset)) { 1134 len = write(sockets[i].fd, 1135 sshbuf_ptr(sockets[i].output), 1136 sshbuf_len(sockets[i].output)); 1137 if (len == -1 && (errno == EAGAIN || 1138 errno == EWOULDBLOCK || 1139 errno == EINTR)) 1140 continue; 1141 if (len <= 0) { 1142 close_socket(&sockets[i]); 1143 break; 1144 } 1145 if ((r = sshbuf_consume(sockets[i].output, 1146 len)) != 0) 1147 fatal("%s: buffer error: %s", 1148 __func__, ssh_err(r)); 1149 } 1150 if (FD_ISSET(sockets[i].fd, readset)) { 1151 len = read(sockets[i].fd, buf, sizeof(buf)); 1152 if (len == -1 && (errno == EAGAIN || 1153 errno == EWOULDBLOCK || 1154 errno == EINTR)) 1155 continue; 1156 if (len <= 0) { 1157 close_socket(&sockets[i]); 1158 break; 1159 } 1160 if ((r = sshbuf_put(sockets[i].input, 1161 buf, len)) != 0) 1162 fatal("%s: buffer error: %s", 1163 __func__, ssh_err(r)); 1164 explicit_bzero(buf, sizeof(buf)); 1165 process_message(&sockets[i]); 1166 } 1167 break; 1168 default: 1169 fatal("Unknown type %d", sockets[i].type); 1170 } 1171} 1172 1173static void 1174cleanup_socket(void) 1175{ 1176 if (cleanup_pid != 0 && getpid() != cleanup_pid) 1177 return; 1178 debug("%s: cleanup", __func__); 1179 if (socket_name[0]) 1180 unlink(socket_name); 1181 if (socket_dir[0]) 1182 rmdir(socket_dir); 1183} 1184 1185void 1186cleanup_exit(int i) 1187{ 1188 cleanup_socket(); 1189 _exit(i); 1190} 1191 1192/*ARGSUSED*/ 1193static void 1194cleanup_handler(int sig) 1195{ 1196 cleanup_socket(); 1197#ifdef ENABLE_PKCS11 1198 pkcs11_terminate(); 1199#endif 1200 _exit(2); 1201} 1202 1203static void 1204check_parent_exists(void) 1205{ 1206 /* 1207 * If our parent has exited then getppid() will return (pid_t)1, 1208 * so testing for that should be safe. 1209 */ 1210 if (parent_pid != -1 && getppid() != parent_pid) { 1211 /* printf("Parent has died - Authentication agent exiting.\n"); */ 1212 cleanup_socket(); 1213 _exit(2); 1214 } 1215} 1216 1217static void 1218usage(void) 1219{ 1220 fprintf(stderr, 1221 "usage: ssh-agent [-c | -s] [-Dd] [-a bind_address] [-E fingerprint_hash]\n" 1222 " [-P pkcs11_whitelist] [-t life] [command [arg ...]]\n" 1223 " ssh-agent [-c | -s] -k\n"); 1224 fprintf(stderr, " -x Exit when the last client disconnects.\n"); 1225 exit(1); 1226} 1227 1228int 1229main(int ac, char **av) 1230{ 1231 int c_flag = 0, d_flag = 0, D_flag = 0, k_flag = 0, s_flag = 0; 1232 int sock, fd, ch, result, saved_errno; 1233 u_int nalloc; 1234 char *shell, *format, *pidstr, *agentsocket = NULL; 1235 fd_set *readsetp = NULL, *writesetp = NULL; 1236#ifdef HAVE_SETRLIMIT 1237 struct rlimit rlim; 1238#endif 1239 extern int optind; 1240 extern char *optarg; 1241 pid_t pid; 1242 char pidstrbuf[1 + 3 * sizeof pid]; 1243 struct timeval *tvp = NULL; 1244 size_t len; 1245 mode_t prev_mask; 1246 1247 ssh_malloc_init(); /* must be called before any mallocs */ 1248 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1249 sanitise_stdfd(); 1250 1251 /* drop */ 1252 setegid(getgid()); 1253 setgid(getgid()); 1254 setuid(geteuid()); 1255 1256#if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE) 1257 /* Disable ptrace on Linux without sgid bit */ 1258 prctl(PR_SET_DUMPABLE, 0); 1259#endif 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 1458skip: 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