crypto/openssh/ssh-agent.c

   1 /* $OpenBSD: ssh-agent.c,v 1.172 2011/06/03 01:37:40 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("$FreeBSD$");
  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 #include <openssl/evp.h>
  54 #include <openssl/md5.h>
  55 #include "openbsd-compat/openssl-compat.h"
  56
  57 #include <errno.h>
  58 #include <fcntl.h>
  59 #ifdef HAVE_PATHS_H
  60 # include <paths.h>
  61 #endif
  62 #include <signal.h>
  63 #include <stdarg.h>
  64 #include <stdio.h>
  65 #include <stdlib.h>
  66 #include <time.h>
  67 #include <string.h>
  68 #include <unistd.h>
  69
  70 #include "xmalloc.h"
  71 #include "ssh.h"
  72 #include "rsa.h"
  73 #include "buffer.h"
  74 #include "key.h"
  75 #include "authfd.h"
  76 #include "compat.h"
  77 #include "log.h"
  78 #include "misc.h"
  79
  80 #ifdef ENABLE_PKCS11
  81 #include "ssh-pkcs11.h"
  82 #endif
  83
  84 #if defined(HAVE_SYS_PRCTL_H)
  85 #include <sys/prctl.h>  /* For prctl() and PR_SET_DUMPABLE */
  86 #endif
  87
  88 typedef enum {
  89         AUTH_UNUSED,
  90         AUTH_SOCKET,
  91         AUTH_CONNECTION
  92 } sock_type;
  93
  94 typedef struct {
  95         int fd;
  96         sock_type type;
  97         Buffer input;
  98         Buffer output;
  99         Buffer request;
 100 } SocketEntry;
 101
 102 u_int sockets_alloc = 0;
 103 SocketEntry *sockets = NULL;
 104
 105 typedef struct identity {
 106         TAILQ_ENTRY(identity) next;
 107         Key *key;
 108         char *comment;
 109         char *provider;
 110         u_int death;
 111         u_int confirm;
 112 } Identity;
 113
 114 typedef struct {
 115         int nentries;
 116         TAILQ_HEAD(idqueue, identity) idlist;
 117 } Idtab;
 118
 119 /* private key table, one per protocol version */
 120 Idtab idtable[3];
 121
 122 int max_fd = 0;
 123
 124 /* pid of shell == parent of agent */
 125 pid_t parent_pid = -1;
 126 u_int parent_alive_interval = 0;
 127
 128 /* pathname and directory for AUTH_SOCKET */
 129 char socket_name[MAXPATHLEN];
 130 char socket_dir[MAXPATHLEN];
 131
 132 /* locking */
 133 int locked = 0;
 134 char *lock_passwd = NULL;
 135
 136 extern char *__progname;
 137
 138 /* Default lifetime (0 == forever) */
 139 static int lifetime = 0;
 140
 141 /*
 142  * Client connection count; incremented in new_socket() and decremented in
 143  * close_socket().  When it reaches 0, ssh-agent will exit.  Since it is
 144  * normally initialized to 1, it will never reach 0.  However, if the -x
 145  * option is specified, it is initialized to 0 in main(); in that case,
 146  * ssh-agent will exit as soon as it has had at least one client but no
 147  * longer has any.
 148  */
 149 static int xcount = 1;
 150
 151 static void
 152 close_socket(SocketEntry *e)
 153 {
 154         int last = 0;
 155
 156         if (e->type == AUTH_CONNECTION) {
 157                 debug("xcount %d -> %d", xcount, xcount - 1);
 158                 if (--xcount == 0)
 159                         last = 1;
 160         }
 161         close(e->fd);
 162         e->fd = -1;
 163         e->type = AUTH_UNUSED;
 164         buffer_free(&e->input);
 165         buffer_free(&e->output);
 166         buffer_free(&e->request);
 167         if (last)
 168                 cleanup_exit(0);
 169 }
 170
 171 static void
 172 idtab_init(void)
 173 {
 174         int i;
 175
 176         for (i = 0; i <=2; i++) {
 177                 TAILQ_INIT(&idtable[i].idlist);
 178                 idtable[i].nentries = 0;
 179         }
 180 }
 181
 182 /* return private key table for requested protocol version */
 183 static Idtab *
 184 idtab_lookup(int version)
 185 {
 186         if (version < 1 || version > 2)
 187                 fatal("internal error, bad protocol version %d", version);
 188         return &idtable[version];
 189 }
 190
 191 static void
 192 free_identity(Identity *id)
 193 {
 194         key_free(id->key);
 195         if (id->provider != NULL)
 196                 xfree(id->provider);
 197         xfree(id->comment);
 198         xfree(id);
 199 }
 200
 201 /* return matching private key for given public key */
 202 static Identity *
 203 lookup_identity(Key *key, int version)
 204 {
 205         Identity *id;
 206
 207         Idtab *tab = idtab_lookup(version);
 208         TAILQ_FOREACH(id, &tab->idlist, next) {
 209                 if (key_equal(key, id->key))
 210                         return (id);
 211         }
 212         return (NULL);
 213 }
 214
 215 /* Check confirmation of keysign request */
 216 static int
 217 confirm_key(Identity *id)
 218 {
 219         char *p;
 220         int ret = -1;
 221
 222         p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX);
 223         if (ask_permission("Allow use of key %s?\nKey fingerprint %s.",
 224             id->comment, p))
 225                 ret = 0;
 226         xfree(p);
 227
 228         return (ret);
 229 }
 230
 231 /* send list of supported public keys to 'client' */
 232 static void
 233 process_request_identities(SocketEntry *e, int version)
 234 {
 235         Idtab *tab = idtab_lookup(version);
 236         Identity *id;
 237         Buffer msg;
 238
 239         buffer_init(&msg);
 240         buffer_put_char(&msg, (version == 1) ?
 241             SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
 242         buffer_put_int(&msg, tab->nentries);
 243         TAILQ_FOREACH(id, &tab->idlist, next) {
 244                 if (id->key->type == KEY_RSA1) {
 245                         buffer_put_int(&msg, BN_num_bits(id->key->rsa->n));
 246                         buffer_put_bignum(&msg, id->key->rsa->e);
 247                         buffer_put_bignum(&msg, id->key->rsa->n);
 248                 } else {
 249                         u_char *blob;
 250                         u_int blen;
 251                         key_to_blob(id->key, &blob, &blen);
 252                         buffer_put_string(&msg, blob, blen);
 253                         xfree(blob);
 254                 }
 255                 buffer_put_cstring(&msg, id->comment);
 256         }
 257         buffer_put_int(&e->output, buffer_len(&msg));
 258         buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
 259         buffer_free(&msg);
 260 }
 261
 262 /* ssh1 only */
 263 static void
 264 process_authentication_challenge1(SocketEntry *e)
 265 {
 266         u_char buf[32], mdbuf[16], session_id[16];
 267         u_int response_type;
 268         BIGNUM *challenge;
 269         Identity *id;
 270         int i, len;
 271         Buffer msg;
 272         MD5_CTX md;
 273         Key *key;
 274
 275         buffer_init(&msg);
 276         key = key_new(KEY_RSA1);
 277         if ((challenge = BN_new()) == NULL)
 278                 fatal("process_authentication_challenge1: BN_new failed");
 279
 280         (void) buffer_get_int(&e->request);                     /* ignored */
 281         buffer_get_bignum(&e->request, key->rsa->e);
 282         buffer_get_bignum(&e->request, key->rsa->n);
 283         buffer_get_bignum(&e->request, challenge);
 284
 285         /* Only protocol 1.1 is supported */
 286         if (buffer_len(&e->request) == 0)
 287                 goto failure;
 288         buffer_get(&e->request, session_id, 16);
 289         response_type = buffer_get_int(&e->request);
 290         if (response_type != 1)
 291                 goto failure;
 292
 293         id = lookup_identity(key, 1);
 294         if (id != NULL && (!id->confirm || confirm_key(id) == 0)) {
 295                 Key *private = id->key;
 296                 /* Decrypt the challenge using the private key. */
 297                 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0)
 298                         goto failure;
 299
 300                 /* The response is MD5 of decrypted challenge plus session id. */
 301                 len = BN_num_bytes(challenge);
 302                 if (len <= 0 || len > 32) {
 303                         logit("process_authentication_challenge: bad challenge length %d", len);
 304                         goto failure;
 305                 }
 306                 memset(buf, 0, 32);
 307                 BN_bn2bin(challenge, buf + 32 - len);
 308                 MD5_Init(&md);
 309                 MD5_Update(&md, buf, 32);
 310                 MD5_Update(&md, session_id, 16);
 311                 MD5_Final(mdbuf, &md);
 312
 313                 /* Send the response. */
 314                 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE);
 315                 for (i = 0; i < 16; i++)
 316                         buffer_put_char(&msg, mdbuf[i]);
 317                 goto send;
 318         }
 319
 320 failure:
 321         /* Unknown identity or protocol error.  Send failure. */
 322         buffer_put_char(&msg, SSH_AGENT_FAILURE);
 323 send:
 324         buffer_put_int(&e->output, buffer_len(&msg));
 325         buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
 326         key_free(key);
 327         BN_clear_free(challenge);
 328         buffer_free(&msg);
 329 }
 330
 331 /* ssh2 only */
 332 static void
 333 process_sign_request2(SocketEntry *e)
 334 {
 335         u_char *blob, *data, *signature = NULL;
 336         u_int blen, dlen, slen = 0;
 337         extern int datafellows;
 338         int odatafellows;
 339         int ok = -1, flags;
 340         Buffer msg;
 341         Key *key;
 342
 343         datafellows = 0;
 344
 345         blob = buffer_get_string(&e->request, &blen);
 346         data = buffer_get_string(&e->request, &dlen);
 347
 348         flags = buffer_get_int(&e->request);
 349         odatafellows = datafellows;
 350         if (flags & SSH_AGENT_OLD_SIGNATURE)
 351                 datafellows = SSH_BUG_SIGBLOB;
 352
 353         key = key_from_blob(blob, blen);
 354         if (key != NULL) {
 355                 Identity *id = lookup_identity(key, 2);
 356                 if (id != NULL && (!id->confirm || confirm_key(id) == 0))
 357                         ok = key_sign(id->key, &signature, &slen, data, dlen);
 358                 key_free(key);
 359         }
 360         buffer_init(&msg);
 361         if (ok == 0) {
 362                 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE);
 363                 buffer_put_string(&msg, signature, slen);
 364         } else {
 365                 buffer_put_char(&msg, SSH_AGENT_FAILURE);
 366         }
 367         buffer_put_int(&e->output, buffer_len(&msg));
 368         buffer_append(&e->output, buffer_ptr(&msg),
 369             buffer_len(&msg));
 370         buffer_free(&msg);
 371         xfree(data);
 372         xfree(blob);
 373         if (signature != NULL)
 374                 xfree(signature);
 375         datafellows = odatafellows;
 376 }
 377
 378 /* shared */
 379 static void
 380 process_remove_identity(SocketEntry *e, int version)
 381 {
 382         u_int blen, bits;
 383         int success = 0;
 384         Key *key = NULL;
 385         u_char *blob;
 386
 387         switch (version) {
 388         case 1:
 389                 key = key_new(KEY_RSA1);
 390                 bits = buffer_get_int(&e->request);
 391                 buffer_get_bignum(&e->request, key->rsa->e);
 392                 buffer_get_bignum(&e->request, key->rsa->n);
 393
 394                 if (bits != key_size(key))
 395                         logit("Warning: identity keysize mismatch: actual %u, announced %u",
 396                             key_size(key), bits);
 397                 break;
 398         case 2:
 399                 blob = buffer_get_string(&e->request, &blen);
 400                 key = key_from_blob(blob, blen);
 401                 xfree(blob);
 402                 break;
 403         }
 404         if (key != NULL) {
 405                 Identity *id = lookup_identity(key, version);
 406                 if (id != NULL) {
 407                         /*
 408                          * We have this key.  Free the old key.  Since we
 409                          * don't want to leave empty slots in the middle of
 410                          * the array, we actually free the key there and move
 411                          * all the entries between the empty slot and the end
 412                          * of the array.
 413                          */
 414                         Idtab *tab = idtab_lookup(version);
 415                         if (tab->nentries < 1)
 416                                 fatal("process_remove_identity: "
 417                                     "internal error: tab->nentries %d",
 418                                     tab->nentries);
 419                         TAILQ_REMOVE(&tab->idlist, id, next);
 420                         free_identity(id);
 421                         tab->nentries--;
 422                         success = 1;
 423                 }
 424                 key_free(key);
 425         }
 426         buffer_put_int(&e->output, 1);
 427         buffer_put_char(&e->output,
 428             success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
 429 }
 430
 431 static void
 432 process_remove_all_identities(SocketEntry *e, int version)
 433 {
 434         Idtab *tab = idtab_lookup(version);
 435         Identity *id;
 436
 437         /* Loop over all identities and clear the keys. */
 438         for (id = TAILQ_FIRST(&tab->idlist); id;
 439             id = TAILQ_FIRST(&tab->idlist)) {
 440                 TAILQ_REMOVE(&tab->idlist, id, next);
 441                 free_identity(id);
 442         }
 443
 444         /* Mark that there are no identities. */
 445         tab->nentries = 0;
 446
 447         /* Send success. */
 448         buffer_put_int(&e->output, 1);
 449         buffer_put_char(&e->output, SSH_AGENT_SUCCESS);
 450 }
 451
 452 /* removes expired keys and returns number of seconds until the next expiry */
 453 static u_int
 454 reaper(void)
 455 {
 456         u_int deadline = 0, now = time(NULL);
 457         Identity *id, *nxt;
 458         int version;
 459         Idtab *tab;
 460
 461         for (version = 1; version < 3; version++) {
 462                 tab = idtab_lookup(version);
 463                 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) {
 464                         nxt = TAILQ_NEXT(id, next);
 465                         if (id->death == 0)
 466                                 continue;
 467                         if (now >= id->death) {
 468                                 debug("expiring key '%s'", id->comment);
 469                                 TAILQ_REMOVE(&tab->idlist, id, next);
 470                                 free_identity(id);
 471                                 tab->nentries--;
 472                         } else
 473                                 deadline = (deadline == 0) ? id->death :
 474                                     MIN(deadline, id->death);
 475                 }
 476         }
 477         if (deadline == 0 || deadline <= now)
 478                 return 0;
 479         else
 480                 return (deadline - now);
 481 }
 482
 483 static void
 484 process_add_identity(SocketEntry *e, int version)
 485 {
 486         Idtab *tab = idtab_lookup(version);
 487         Identity *id;
 488         int type, success = 0, death = 0, confirm = 0;
 489         char *type_name, *comment;
 490         Key *k = NULL;
 491 #ifdef OPENSSL_HAS_ECC
 492         BIGNUM *exponent;
 493         EC_POINT *q;
 494         char *curve;
 495 #endif
 496         u_char *cert;
 497         u_int len;
 498
 499         switch (version) {
 500         case 1:
 501                 k = key_new_private(KEY_RSA1);
 502                 (void) buffer_get_int(&e->request);             /* ignored */
 503                 buffer_get_bignum(&e->request, k->rsa->n);
 504                 buffer_get_bignum(&e->request, k->rsa->e);
 505                 buffer_get_bignum(&e->request, k->rsa->d);
 506                 buffer_get_bignum(&e->request, k->rsa->iqmp);
 507
 508                 /* SSH and SSL have p and q swapped */
 509                 buffer_get_bignum(&e->request, k->rsa->q);      /* p */
 510                 buffer_get_bignum(&e->request, k->rsa->p);      /* q */
 511
 512                 /* Generate additional parameters */
 513                 rsa_generate_additional_parameters(k->rsa);
 514                 break;
 515         case 2:
 516                 type_name = buffer_get_string(&e->request, NULL);
 517                 type = key_type_from_name(type_name);
 518                 switch (type) {
 519                 case KEY_DSA:
 520                         k = key_new_private(type);
 521                         buffer_get_bignum2(&e->request, k->dsa->p);
 522                         buffer_get_bignum2(&e->request, k->dsa->q);
 523                         buffer_get_bignum2(&e->request, k->dsa->g);
 524                         buffer_get_bignum2(&e->request, k->dsa->pub_key);
 525                         buffer_get_bignum2(&e->request, k->dsa->priv_key);
 526                         break;
 527                 case KEY_DSA_CERT_V00:
 528                 case KEY_DSA_CERT:
 529                         cert = buffer_get_string(&e->request, &len);
 530                         if ((k = key_from_blob(cert, len)) == NULL)
 531                                 fatal("Certificate parse failed");
 532                         xfree(cert);
 533                         key_add_private(k);
 534                         buffer_get_bignum2(&e->request, k->dsa->priv_key);
 535                         break;
 536 #ifdef OPENSSL_HAS_ECC
 537                 case KEY_ECDSA:
 538                         k = key_new_private(type);
 539                         k->ecdsa_nid = key_ecdsa_nid_from_name(type_name);
 540                         curve = buffer_get_string(&e->request, NULL);
 541                         if (k->ecdsa_nid != key_curve_name_to_nid(curve))
 542                                 fatal("%s: curve names mismatch", __func__);
 543                         xfree(curve);
 544                         k->ecdsa = EC_KEY_new_by_curve_name(k->ecdsa_nid);
 545                         if (k->ecdsa == NULL)
 546                                 fatal("%s: EC_KEY_new_by_curve_name failed",
 547                                     __func__);
 548                         q = EC_POINT_new(EC_KEY_get0_group(k->ecdsa));
 549                         if (q == NULL)
 550                                 fatal("%s: BN_new failed", __func__);
 551                         if ((exponent = BN_new()) == NULL)
 552                                 fatal("%s: BN_new failed", __func__);
 553                         buffer_get_ecpoint(&e->request,
 554                                 EC_KEY_get0_group(k->ecdsa), q);
 555                         buffer_get_bignum2(&e->request, exponent);
 556                         if (EC_KEY_set_public_key(k->ecdsa, q) != 1)
 557                                 fatal("%s: EC_KEY_set_public_key failed",
 558                                     __func__);
 559                         if (EC_KEY_set_private_key(k->ecdsa, exponent) != 1)
 560                                 fatal("%s: EC_KEY_set_private_key failed",
 561                                     __func__);
 562                         if (key_ec_validate_public(EC_KEY_get0_group(k->ecdsa),
 563                             EC_KEY_get0_public_key(k->ecdsa)) != 0)
 564                                 fatal("%s: bad ECDSA public key", __func__);
 565                         if (key_ec_validate_private(k->ecdsa) != 0)
 566                                 fatal("%s: bad ECDSA private key", __func__);
 567                         BN_clear_free(exponent);
 568                         EC_POINT_free(q);
 569                         break;
 570                 case KEY_ECDSA_CERT:
 571                         cert = buffer_get_string(&e->request, &len);
 572                         if ((k = key_from_blob(cert, len)) == NULL)
 573                                 fatal("Certificate parse failed");
 574                         xfree(cert);
 575                         key_add_private(k);
 576                         if ((exponent = BN_new()) == NULL)
 577                                 fatal("%s: BN_new failed", __func__);
 578                         buffer_get_bignum2(&e->request, exponent);
 579                         if (EC_KEY_set_private_key(k->ecdsa, exponent) != 1)
 580                                 fatal("%s: EC_KEY_set_private_key failed",
 581                                     __func__);
 582                         if (key_ec_validate_public(EC_KEY_get0_group(k->ecdsa),
 583                             EC_KEY_get0_public_key(k->ecdsa)) != 0 ||
 584                             key_ec_validate_private(k->ecdsa) != 0)
 585                                 fatal("%s: bad ECDSA key", __func__);
 586                         BN_clear_free(exponent);
 587                         break;
 588 #endif /* OPENSSL_HAS_ECC */
 589                 case KEY_RSA:
 590                         k = key_new_private(type);
 591                         buffer_get_bignum2(&e->request, k->rsa->n);
 592                         buffer_get_bignum2(&e->request, k->rsa->e);
 593                         buffer_get_bignum2(&e->request, k->rsa->d);
 594                         buffer_get_bignum2(&e->request, k->rsa->iqmp);
 595                         buffer_get_bignum2(&e->request, k->rsa->p);
 596                         buffer_get_bignum2(&e->request, k->rsa->q);
 597
 598                         /* Generate additional parameters */
 599                         rsa_generate_additional_parameters(k->rsa);
 600                         break;
 601                 case KEY_RSA_CERT_V00:
 602                 case KEY_RSA_CERT:
 603                         cert = buffer_get_string(&e->request, &len);
 604                         if ((k = key_from_blob(cert, len)) == NULL)
 605                                 fatal("Certificate parse failed");
 606                         xfree(cert);
 607                         key_add_private(k);
 608                         buffer_get_bignum2(&e->request, k->rsa->d);
 609                         buffer_get_bignum2(&e->request, k->rsa->iqmp);
 610                         buffer_get_bignum2(&e->request, k->rsa->p);
 611                         buffer_get_bignum2(&e->request, k->rsa->q);
 612                         break;
 613                 default:
 614                         xfree(type_name);
 615                         buffer_clear(&e->request);
 616                         goto send;
 617                 }
 618                 xfree(type_name);
 619                 break;
 620         }
 621         /* enable blinding */
 622         switch (k->type) {
 623         case KEY_RSA:
 624         case KEY_RSA_CERT_V00:
 625         case KEY_RSA_CERT:
 626         case KEY_RSA1:
 627                 if (RSA_blinding_on(k->rsa, NULL) != 1) {
 628                         error("process_add_identity: RSA_blinding_on failed");
 629                         key_free(k);
 630                         goto send;
 631                 }
 632                 break;
 633         }
 634         comment = buffer_get_string(&e->request, NULL);
 635         if (k == NULL) {
 636                 xfree(comment);
 637                 goto send;
 638         }
 639         while (buffer_len(&e->request)) {
 640                 switch ((type = buffer_get_char(&e->request))) {
 641                 case SSH_AGENT_CONSTRAIN_LIFETIME:
 642                         death = time(NULL) + buffer_get_int(&e->request);
 643                         break;
 644                 case SSH_AGENT_CONSTRAIN_CONFIRM:
 645                         confirm = 1;
 646                         break;
 647                 default:
 648                         error("process_add_identity: "
 649                             "Unknown constraint type %d", type);
 650                         xfree(comment);
 651                         key_free(k);
 652                         goto send;
 653                 }
 654         }
 655         success = 1;
 656         if (lifetime && !death)
 657                 death = time(NULL) + lifetime;
 658         if ((id = lookup_identity(k, version)) == NULL) {
 659                 id = xcalloc(1, sizeof(Identity));
 660                 id->key = k;
 661                 TAILQ_INSERT_TAIL(&tab->idlist, id, next);
 662                 /* Increment the number of identities. */
 663                 tab->nentries++;
 664         } else {
 665                 key_free(k);
 666                 xfree(id->comment);
 667         }
 668         id->comment = comment;
 669         id->death = death;
 670         id->confirm = confirm;
 671 send:
 672         buffer_put_int(&e->output, 1);
 673         buffer_put_char(&e->output,
 674             success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
 675 }
 676
 677 /* XXX todo: encrypt sensitive data with passphrase */
 678 static void
 679 process_lock_agent(SocketEntry *e, int lock)
 680 {
 681         int success = 0;
 682         char *passwd;
 683
 684         passwd = buffer_get_string(&e->request, NULL);
 685         if (locked && !lock && strcmp(passwd, lock_passwd) == 0) {
 686                 locked = 0;
 687                 memset(lock_passwd, 0, strlen(lock_passwd));
 688                 xfree(lock_passwd);
 689                 lock_passwd = NULL;
 690                 success = 1;
 691         } else if (!locked && lock) {
 692                 locked = 1;
 693                 lock_passwd = xstrdup(passwd);
 694                 success = 1;
 695         }
 696         memset(passwd, 0, strlen(passwd));
 697         xfree(passwd);
 698
 699         buffer_put_int(&e->output, 1);
 700         buffer_put_char(&e->output,
 701             success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
 702 }
 703
 704 static void
 705 no_identities(SocketEntry *e, u_int type)
 706 {
 707         Buffer msg;
 708
 709         buffer_init(&msg);
 710         buffer_put_char(&msg,
 711             (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ?
 712             SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
 713         buffer_put_int(&msg, 0);
 714         buffer_put_int(&e->output, buffer_len(&msg));
 715         buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
 716         buffer_free(&msg);
 717 }
 718
 719 #ifdef ENABLE_PKCS11
 720 static void
 721 process_add_smartcard_key(SocketEntry *e)
 722 {
 723         char *provider = NULL, *pin;
 724         int i, type, version, count = 0, success = 0, death = 0, confirm = 0;
 725         Key **keys = NULL, *k;
 726         Identity *id;
 727         Idtab *tab;
 728
 729         provider = buffer_get_string(&e->request, NULL);
 730         pin = buffer_get_string(&e->request, NULL);
 731
 732         while (buffer_len(&e->request)) {
 733                 switch ((type = buffer_get_char(&e->request))) {
 734                 case SSH_AGENT_CONSTRAIN_LIFETIME:
 735                         death = time(NULL) + buffer_get_int(&e->request);
 736                         break;
 737                 case SSH_AGENT_CONSTRAIN_CONFIRM:
 738                         confirm = 1;
 739                         break;
 740                 default:
 741                         error("process_add_smartcard_key: "
 742                             "Unknown constraint type %d", type);
 743                         goto send;
 744                 }
 745         }
 746         if (lifetime && !death)
 747                 death = time(NULL) + lifetime;
 748
 749         count = pkcs11_add_provider(provider, pin, &keys);
 750         for (i = 0; i < count; i++) {
 751                 k = keys[i];
 752                 version = k->type == KEY_RSA1 ? 1 : 2;
 753                 tab = idtab_lookup(version);
 754                 if (lookup_identity(k, version) == NULL) {
 755                         id = xcalloc(1, sizeof(Identity));
 756                         id->key = k;
 757                         id->provider = xstrdup(provider);
 758                         id->comment = xstrdup(provider); /* XXX */
 759                         id->death = death;
 760                         id->confirm = confirm;
 761                         TAILQ_INSERT_TAIL(&tab->idlist, id, next);
 762                         tab->nentries++;
 763                         success = 1;
 764                 } else {
 765                         key_free(k);
 766                 }
 767                 keys[i] = NULL;
 768         }
 769 send:
 770         if (pin)
 771                 xfree(pin);
 772         if (provider)
 773                 xfree(provider);
 774         if (keys)
 775                 xfree(keys);
 776         buffer_put_int(&e->output, 1);
 777         buffer_put_char(&e->output,
 778             success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
 779 }
 780
 781 static void
 782 process_remove_smartcard_key(SocketEntry *e)
 783 {
 784         char *provider = NULL, *pin = NULL;
 785         int version, success = 0;
 786         Identity *id, *nxt;
 787         Idtab *tab;
 788
 789         provider = buffer_get_string(&e->request, NULL);
 790         pin = buffer_get_string(&e->request, NULL);
 791         xfree(pin);
 792
 793         for (version = 1; version < 3; version++) {
 794                 tab = idtab_lookup(version);
 795                 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) {
 796                         nxt = TAILQ_NEXT(id, next);
 797                         if (!strcmp(provider, id->provider)) {
 798                                 TAILQ_REMOVE(&tab->idlist, id, next);
 799                                 free_identity(id);
 800                                 tab->nentries--;
 801                         }
 802                 }
 803         }
 804         if (pkcs11_del_provider(provider) == 0)
 805                 success = 1;
 806         else
 807                 error("process_remove_smartcard_key:"
 808                     " pkcs11_del_provider failed");
 809         xfree(provider);
 810         buffer_put_int(&e->output, 1);
 811         buffer_put_char(&e->output,
 812             success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
 813 }
 814 #endif /* ENABLE_PKCS11 */
 815
 816 /* dispatch incoming messages */
 817
 818 static void
 819 process_message(SocketEntry *e)
 820 {
 821         u_int msg_len, type;
 822         u_char *cp;
 823
 824         if (buffer_len(&e->input) < 5)
 825                 return;         /* Incomplete message. */
 826         cp = buffer_ptr(&e->input);
 827         msg_len = get_u32(cp);
 828         if (msg_len > 256 * 1024) {
 829                 close_socket(e);
 830                 return;
 831         }
 832         if (buffer_len(&e->input) < msg_len + 4)
 833                 return;
 834
 835         /* move the current input to e->request */
 836         buffer_consume(&e->input, 4);
 837         buffer_clear(&e->request);
 838         buffer_append(&e->request, buffer_ptr(&e->input), msg_len);
 839         buffer_consume(&e->input, msg_len);
 840         type = buffer_get_char(&e->request);
 841
 842         /* check wheter agent is locked */
 843         if (locked && type != SSH_AGENTC_UNLOCK) {
 844                 buffer_clear(&e->request);
 845                 switch (type) {
 846                 case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
 847                 case SSH2_AGENTC_REQUEST_IDENTITIES:
 848                         /* send empty lists */
 849                         no_identities(e, type);
 850                         break;
 851                 default:
 852                         /* send a fail message for all other request types */
 853                         buffer_put_int(&e->output, 1);
 854                         buffer_put_char(&e->output, SSH_AGENT_FAILURE);
 855                 }
 856                 return;
 857         }
 858
 859         debug("type %d", type);
 860         switch (type) {
 861         case SSH_AGENTC_LOCK:
 862         case SSH_AGENTC_UNLOCK:
 863                 process_lock_agent(e, type == SSH_AGENTC_LOCK);
 864                 break;
 865         /* ssh1 */
 866         case SSH_AGENTC_RSA_CHALLENGE:
 867                 process_authentication_challenge1(e);
 868                 break;
 869         case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
 870                 process_request_identities(e, 1);
 871                 break;
 872         case SSH_AGENTC_ADD_RSA_IDENTITY:
 873         case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED:
 874                 process_add_identity(e, 1);
 875                 break;
 876         case SSH_AGENTC_REMOVE_RSA_IDENTITY:
 877                 process_remove_identity(e, 1);
 878                 break;
 879         case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
 880                 process_remove_all_identities(e, 1);
 881                 break;
 882         /* ssh2 */
 883         case SSH2_AGENTC_SIGN_REQUEST:
 884                 process_sign_request2(e);
 885                 break;
 886         case SSH2_AGENTC_REQUEST_IDENTITIES:
 887                 process_request_identities(e, 2);
 888                 break;
 889         case SSH2_AGENTC_ADD_IDENTITY:
 890         case SSH2_AGENTC_ADD_ID_CONSTRAINED:
 891                 process_add_identity(e, 2);
 892                 break;
 893         case SSH2_AGENTC_REMOVE_IDENTITY:
 894                 process_remove_identity(e, 2);
 895                 break;
 896         case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
 897                 process_remove_all_identities(e, 2);
 898                 break;
 899 #ifdef ENABLE_PKCS11
 900         case SSH_AGENTC_ADD_SMARTCARD_KEY:
 901         case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED:
 902                 process_add_smartcard_key(e);
 903                 break;
 904         case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
 905                 process_remove_smartcard_key(e);
 906                 break;
 907 #endif /* ENABLE_PKCS11 */
 908         default:
 909                 /* Unknown message.  Respond with failure. */
 910                 error("Unknown message %d", type);
 911                 buffer_clear(&e->request);
 912                 buffer_put_int(&e->output, 1);
 913                 buffer_put_char(&e->output, SSH_AGENT_FAILURE);
 914                 break;
 915         }
 916 }
 917
 918 static void
 919 new_socket(sock_type type, int fd)
 920 {
 921         u_int i, old_alloc, new_alloc;
 922
 923         if (type == AUTH_CONNECTION) {
 924                 debug("xcount %d -> %d", xcount, xcount + 1);
 925                 ++xcount;
 926         }
 927         set_nonblock(fd);
 928
 929         if (fd > max_fd)
 930                 max_fd = fd;
 931
 932         for (i = 0; i < sockets_alloc; i++)
 933                 if (sockets[i].type == AUTH_UNUSED) {
 934                         sockets[i].fd = fd;
 935                         buffer_init(&sockets[i].input);
 936                         buffer_init(&sockets[i].output);
 937                         buffer_init(&sockets[i].request);
 938                         sockets[i].type = type;
 939                         return;
 940                 }
 941         old_alloc = sockets_alloc;
 942         new_alloc = sockets_alloc + 10;
 943         sockets = xrealloc(sockets, new_alloc, sizeof(sockets[0]));
 944         for (i = old_alloc; i < new_alloc; i++)
 945                 sockets[i].type = AUTH_UNUSED;
 946         sockets_alloc = new_alloc;
 947         sockets[old_alloc].fd = fd;
 948         buffer_init(&sockets[old_alloc].input);
 949         buffer_init(&sockets[old_alloc].output);
 950         buffer_init(&sockets[old_alloc].request);
 951         sockets[old_alloc].type = type;
 952 }
 953
 954 static int
 955 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp,
 956     struct timeval **tvpp)
 957 {
 958         u_int i, sz, deadline;
 959         int n = 0;
 960         static struct timeval tv;
 961
 962         for (i = 0; i < sockets_alloc; i++) {
 963                 switch (sockets[i].type) {
 964                 case AUTH_SOCKET:
 965                 case AUTH_CONNECTION:
 966                         n = MAX(n, sockets[i].fd);
 967                         break;
 968                 case AUTH_UNUSED:
 969                         break;
 970                 default:
 971                         fatal("Unknown socket type %d", sockets[i].type);
 972                         break;
 973                 }
 974         }
 975
 976         sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
 977         if (*fdrp == NULL || sz > *nallocp) {
 978                 if (*fdrp)
 979                         xfree(*fdrp);
 980                 if (*fdwp)
 981                         xfree(*fdwp);
 982                 *fdrp = xmalloc(sz);
 983                 *fdwp = xmalloc(sz);
 984                 *nallocp = sz;
 985         }
 986         if (n < *fdl)
 987                 debug("XXX shrink: %d < %d", n, *fdl);
 988         *fdl = n;
 989         memset(*fdrp, 0, sz);
 990         memset(*fdwp, 0, sz);
 991
 992         for (i = 0; i < sockets_alloc; i++) {
 993                 switch (sockets[i].type) {
 994                 case AUTH_SOCKET:
 995                 case AUTH_CONNECTION:
 996                         FD_SET(sockets[i].fd, *fdrp);
 997                         if (buffer_len(&sockets[i].output) > 0)
 998                                 FD_SET(sockets[i].fd, *fdwp);
 999                         break;
1000                 default:
1001                         break;
1002                 }
1003         }
1004         deadline = reaper();
1005         if (parent_alive_interval != 0)
1006                 deadline = (deadline == 0) ? parent_alive_interval :
1007                     MIN(deadline, parent_alive_interval);
1008         if (deadline == 0) {
1009                 *tvpp = NULL;
1010         } else {
1011                 tv.tv_sec = deadline;
1012                 tv.tv_usec = 0;
1013                 *tvpp = &tv;
1014         }
1015         return (1);
1016 }
1017
1018 static void
1019 after_select(fd_set *readset, fd_set *writeset)
1020 {
1021         struct sockaddr_un sunaddr;
1022         socklen_t slen;
1023         char buf[1024];
1024         int len, sock;
1025         u_int i, orig_alloc;
1026         uid_t euid;
1027         gid_t egid;
1028
1029         for (i = 0, orig_alloc = sockets_alloc; i < orig_alloc; i++)
1030                 switch (sockets[i].type) {
1031                 case AUTH_UNUSED:
1032                         break;
1033                 case AUTH_SOCKET:
1034                         if (FD_ISSET(sockets[i].fd, readset)) {
1035                                 slen = sizeof(sunaddr);
1036                                 sock = accept(sockets[i].fd,
1037                                     (struct sockaddr *)&sunaddr, &slen);
1038                                 if (sock < 0) {
1039                                         error("accept from AUTH_SOCKET: %s",
1040                                             strerror(errno));
1041                                         break;
1042                                 }
1043                                 if (getpeereid(sock, &euid, &egid) < 0) {
1044                                         error("getpeereid %d failed: %s",
1045                                             sock, strerror(errno));
1046                                         close(sock);
1047                                         break;
1048                                 }
1049                                 if ((euid != 0) && (getuid() != euid)) {
1050                                         error("uid mismatch: "
1051                                             "peer euid %u != uid %u",
1052                                             (u_int) euid, (u_int) getuid());
1053                                         close(sock);
1054                                         break;
1055                                 }
1056                                 new_socket(AUTH_CONNECTION, sock);
1057                         }
1058                         break;
1059                 case AUTH_CONNECTION:
1060                         if (buffer_len(&sockets[i].output) > 0 &&
1061                             FD_ISSET(sockets[i].fd, writeset)) {
1062                                 len = write(sockets[i].fd,
1063                                     buffer_ptr(&sockets[i].output),
1064                                     buffer_len(&sockets[i].output));
1065                                 if (len == -1 && (errno == EAGAIN ||
1066                                     errno == EWOULDBLOCK ||
1067                                     errno == EINTR))
1068                                         continue;
1069                                 if (len <= 0) {
1070                                         close_socket(&sockets[i]);
1071                                         break;
1072                                 }
1073                                 buffer_consume(&sockets[i].output, len);
1074                         }
1075                         if (FD_ISSET(sockets[i].fd, readset)) {
1076                                 len = read(sockets[i].fd, buf, sizeof(buf));
1077                                 if (len == -1 && (errno == EAGAIN ||
1078                                     errno == EWOULDBLOCK ||
1079                                     errno == EINTR))
1080                                         continue;
1081                                 if (len <= 0) {
1082                                         close_socket(&sockets[i]);
1083                                         break;
1084                                 }
1085                                 buffer_append(&sockets[i].input, buf, len);
1086                                 process_message(&sockets[i]);
1087                         }
1088                         break;
1089                 default:
1090                         fatal("Unknown type %d", sockets[i].type);
1091                 }
1092 }
1093
1094 static void
1095 cleanup_socket(void)
1096 {
1097         if (socket_name[0])
1098                 unlink(socket_name);
1099         if (socket_dir[0])
1100                 rmdir(socket_dir);
1101 }
1102
1103 void
1104 cleanup_exit(int i)
1105 {
1106         cleanup_socket();
1107         _exit(i);
1108 }
1109
1110 /*ARGSUSED*/
1111 static void
1112 cleanup_handler(int sig)
1113 {
1114         cleanup_socket();
1115 #ifdef ENABLE_PKCS11
1116         pkcs11_terminate();
1117 #endif
1118         _exit(2);
1119 }
1120
1121 static void
1122 check_parent_exists(void)
1123 {
1124         /*
1125          * If our parent has exited then getppid() will return (pid_t)1,
1126          * so testing for that should be safe.
1127          */
1128         if (parent_pid != -1 && getppid() != parent_pid) {
1129                 /* printf("Parent has died - Authentication agent exiting.\n"); */
1130                 cleanup_socket();
1131                 _exit(2);
1132         }
1133 }
1134
1135 static void
1136 usage(void)
1137 {
1138         fprintf(stderr, "usage: %s [options] [command [arg ...]]\n",
1139             __progname);
1140         fprintf(stderr, "Options:\n");
1141         fprintf(stderr, "  -c          Generate C-shell commands on stdout.\n");
1142         fprintf(stderr, "  -s          Generate Bourne shell commands on stdout.\n");
1143         fprintf(stderr, "  -k          Kill the current agent.\n");
1144         fprintf(stderr, "  -d          Debug mode.\n");
1145         fprintf(stderr, "  -a socket   Bind agent socket to given name.\n");
1146         fprintf(stderr, "  -t life     Default identity lifetime (seconds).\n");
1147         fprintf(stderr, "  -x          Exit when the last client disconnects.\n");
1148         exit(1);
1149 }
1150
1151 int
1152 main(int ac, char **av)
1153 {
1154         int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0;
1155         int sock, fd, ch, result, saved_errno;
1156         u_int nalloc;
1157         char *shell, *format, *pidstr, *agentsocket = NULL;
1158         fd_set *readsetp = NULL, *writesetp = NULL;
1159         struct sockaddr_un sunaddr;
1160 #ifdef HAVE_SETRLIMIT
1161         struct rlimit rlim;
1162 #endif
1163         int prev_mask;
1164         extern int optind;
1165         extern char *optarg;
1166         pid_t pid;
1167         char pidstrbuf[1 + 3 * sizeof pid];
1168         struct timeval *tvp = NULL;
1169         size_t len;
1170
1171         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1172         sanitise_stdfd();
1173
1174         /* drop */
1175         setegid(getgid());
1176         setgid(getgid());
1177         setuid(geteuid());
1178
1179 #if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE)
1180         /* Disable ptrace on Linux without sgid bit */
1181         prctl(PR_SET_DUMPABLE, 0);
1182 #endif
1183
1184         OpenSSL_add_all_algorithms();
1185
1186         __progname = ssh_get_progname(av[0]);
1187         seed_rng();
1188
1189         while ((ch = getopt(ac, av, "cdksa:t:x")) != -1) {
1190                 switch (ch) {
1191                 case 'c':
1192                         if (s_flag)
1193                                 usage();
1194                         c_flag++;
1195                         break;
1196                 case 'k':
1197                         k_flag++;
1198                         break;
1199                 case 's':
1200                         if (c_flag)
1201                                 usage();
1202                         s_flag++;
1203                         break;
1204                 case 'd':
1205                         if (d_flag)
1206                                 usage();
1207                         d_flag++;
1208                         break;
1209                 case 'a':
1210                         agentsocket = optarg;
1211                         break;
1212                 case 't':
1213                         if ((lifetime = convtime(optarg)) == -1) {
1214                                 fprintf(stderr, "Invalid lifetime\n");
1215                                 usage();
1216                         }
1217                         break;
1218                 case 'x':
1219                         xcount = 0;
1220                         break;
1221                 default:
1222                         usage();
1223                 }
1224         }
1225         ac -= optind;
1226         av += optind;
1227
1228         if (ac > 0 && (c_flag || k_flag || s_flag || d_flag))
1229                 usage();
1230
1231         if (ac == 0 && !c_flag && !s_flag) {
1232                 shell = getenv("SHELL");
1233                 if (shell != NULL && (len = strlen(shell)) > 2 &&
1234                     strncmp(shell + len - 3, "csh", 3) == 0)
1235                         c_flag = 1;
1236         }
1237         if (k_flag) {
1238                 const char *errstr = NULL;
1239
1240                 pidstr = getenv(SSH_AGENTPID_ENV_NAME);
1241                 if (pidstr == NULL) {
1242                         fprintf(stderr, "%s not set, cannot kill agent\n",
1243                             SSH_AGENTPID_ENV_NAME);
1244                         exit(1);
1245                 }
1246                 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr);
1247                 if (errstr) {
1248                         fprintf(stderr,
1249                             "%s=\"%s\", which is not a good PID: %s\n",
1250                             SSH_AGENTPID_ENV_NAME, pidstr, errstr);
1251                         exit(1);
1252                 }
1253                 if (kill(pid, SIGTERM) == -1) {
1254                         perror("kill");
1255                         exit(1);
1256                 }
1257                 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
1258                 printf(format, SSH_AUTHSOCKET_ENV_NAME);
1259                 printf(format, SSH_AGENTPID_ENV_NAME);
1260                 printf("echo Agent pid %ld killed;\n", (long)pid);
1261                 exit(0);
1262         }
1263         parent_pid = getpid();
1264
1265         if (agentsocket == NULL) {
1266                 /* Create private directory for agent socket */
1267                 mktemp_proto(socket_dir, sizeof(socket_dir));
1268                 if (mkdtemp(socket_dir) == NULL) {
1269                         perror("mkdtemp: private socket dir");
1270                         exit(1);
1271                 }
1272                 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir,
1273                     (long)parent_pid);
1274         } else {
1275                 /* Try to use specified agent socket */
1276                 socket_dir[0] = '\0';
1277                 strlcpy(socket_name, agentsocket, sizeof socket_name);
1278         }
1279
1280         /*
1281          * Create socket early so it will exist before command gets run from
1282          * the parent.
1283          */
1284         sock = socket(AF_UNIX, SOCK_STREAM, 0);
1285         if (sock < 0) {
1286                 perror("socket");
1287                 *socket_name = '\0'; /* Don't unlink any existing file */
1288                 cleanup_exit(1);
1289         }
1290         memset(&sunaddr, 0, sizeof(sunaddr));
1291         sunaddr.sun_family = AF_UNIX;
1292         strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path));
1293         prev_mask = umask(0177);
1294         if (bind(sock, (struct sockaddr *) &sunaddr, sizeof(sunaddr)) < 0) {
1295                 perror("bind");
1296                 *socket_name = '\0'; /* Don't unlink any existing file */
1297                 umask(prev_mask);
1298                 cleanup_exit(1);
1299         }
1300         umask(prev_mask);
1301         if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
1302                 perror("listen");
1303                 cleanup_exit(1);
1304         }
1305
1306         /*
1307          * Fork, and have the parent execute the command, if any, or present
1308          * the socket data.  The child continues as the authentication agent.
1309          */
1310         if (d_flag) {
1311                 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1);
1312                 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1313                 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1314                     SSH_AUTHSOCKET_ENV_NAME);
1315                 printf("echo Agent pid %ld;\n", (long)parent_pid);
1316                 goto skip;
1317         }
1318         pid = fork();
1319         if (pid == -1) {
1320                 perror("fork");
1321                 cleanup_exit(1);
1322         }
1323         if (pid != 0) {         /* Parent - execute the given command. */
1324                 close(sock);
1325                 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid);
1326                 if (ac == 0) {
1327                         format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1328                         printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1329                             SSH_AUTHSOCKET_ENV_NAME);
1330                         printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
1331                             SSH_AGENTPID_ENV_NAME);
1332                         printf("echo Agent pid %ld;\n", (long)pid);
1333                         exit(0);
1334                 }
1335                 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 ||
1336                     setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) {
1337                         perror("setenv");
1338                         exit(1);
1339                 }
1340                 execvp(av[0], av);
1341                 perror(av[0]);
1342                 exit(1);
1343         }
1344         /* child */
1345         log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0);
1346
1347         if (setsid() == -1) {
1348                 error("setsid: %s", strerror(errno));
1349                 cleanup_exit(1);
1350         }
1351
1352         (void)chdir("/");
1353         if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1354                 /* XXX might close listen socket */
1355                 (void)dup2(fd, STDIN_FILENO);
1356                 (void)dup2(fd, STDOUT_FILENO);
1357                 (void)dup2(fd, STDERR_FILENO);
1358                 if (fd > 2)
1359                         close(fd);
1360         }
1361
1362 #ifdef HAVE_SETRLIMIT
1363         /* deny core dumps, since memory contains unencrypted private keys */
1364         rlim.rlim_cur = rlim.rlim_max = 0;
1365         if (setrlimit(RLIMIT_CORE, &rlim) < 0) {
1366                 error("setrlimit RLIMIT_CORE: %s", strerror(errno));
1367                 cleanup_exit(1);
1368         }
1369 #endif
1370
1371 skip:
1372
1373 #ifdef ENABLE_PKCS11
1374         pkcs11_init(0);
1375 #endif
1376         new_socket(AUTH_SOCKET, sock);
1377         if (ac > 0)
1378                 parent_alive_interval = 10;
1379         idtab_init();
1380         signal(SIGINT, d_flag ? cleanup_handler : SIG_IGN);
1381         signal(SIGPIPE, SIG_IGN);
1382         signal(SIGHUP, cleanup_handler);
1383         signal(SIGTERM, cleanup_handler);
1384         nalloc = 0;
1385
1386         while (1) {
1387                 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp);
1388                 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp);
1389                 saved_errno = errno;
1390                 if (parent_alive_interval != 0)
1391                         check_parent_exists();
1392                 (void) reaper();        /* remove expired keys */
1393                 if (result < 0) {
1394                         if (saved_errno == EINTR)
1395                                 continue;
1396                         fatal("select: %s", strerror(saved_errno));
1397                 } else if (result > 0)
1398                         after_select(readsetp, writesetp);
1399         }
1400         /* NOTREACHED */
1401 }