crypto/openssh/ssh-agent.c

   1 /* $OpenBSD: ssh-agent.c,v 1.166 2010/04/16 01:47:26 djm Exp $ */
   2 /*
   3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   5  *                    All rights reserved
   6  * The authentication agent program.
   7  *
   8  * As far as I am concerned, the code I have written for this software
   9  * can be used freely for any purpose.  Any derived versions of this
  10  * software must be clearly marked as such, and if the derived work is
  11  * incompatible with the protocol description in the RFC file, it must be
  12  * called by a name other than "ssh" or "Secure Shell".
  13  *
  14  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  15  *
  16  * Redistribution and use in source and binary forms, with or without
  17  * modification, are permitted provided that the following conditions
  18  * are met:
  19  * 1. Redistributions of source code must retain the above copyright
  20  *    notice, this list of conditions and the following disclaimer.
  21  * 2. Redistributions in binary form must reproduce the above copyright
  22  *    notice, this list of conditions and the following disclaimer in the
  23  *    documentation and/or other materials provided with the distribution.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  26  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  27  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  28  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  29  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  30  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  31  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  32  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  33  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  34  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  35  */
  36
  37 #include "includes.h"
  38 __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 static void
 142 close_socket(SocketEntry *e)
 143 {
 144         close(e->fd);
 145         e->fd = -1;
 146         e->type = AUTH_UNUSED;
 147         buffer_free(&e->input);
 148         buffer_free(&e->output);
 149         buffer_free(&e->request);
 150 }
 151
 152 static void
 153 idtab_init(void)
 154 {
 155         int i;
 156
 157         for (i = 0; i <=2; i++) {
 158                 TAILQ_INIT(&idtable[i].idlist);
 159                 idtable[i].nentries = 0;
 160         }
 161 }
 162
 163 /* return private key table for requested protocol version */
 164 static Idtab *
 165 idtab_lookup(int version)
 166 {
 167         if (version < 1 || version > 2)
 168                 fatal("internal error, bad protocol version %d", version);
 169         return &idtable[version];
 170 }
 171
 172 static void
 173 free_identity(Identity *id)
 174 {
 175         key_free(id->key);
 176         if (id->provider != NULL)
 177                 xfree(id->provider);
 178         xfree(id->comment);
 179         xfree(id);
 180 }
 181
 182 /* return matching private key for given public key */
 183 static Identity *
 184 lookup_identity(Key *key, int version)
 185 {
 186         Identity *id;
 187
 188         Idtab *tab = idtab_lookup(version);
 189         TAILQ_FOREACH(id, &tab->idlist, next) {
 190                 if (key_equal(key, id->key))
 191                         return (id);
 192         }
 193         return (NULL);
 194 }
 195
 196 /* Check confirmation of keysign request */
 197 static int
 198 confirm_key(Identity *id)
 199 {
 200         char *p;
 201         int ret = -1;
 202
 203         p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX);
 204         if (ask_permission("Allow use of key %s?\nKey fingerprint %s.",
 205             id->comment, p))
 206                 ret = 0;
 207         xfree(p);
 208
 209         return (ret);
 210 }
 211
 212 /* send list of supported public keys to 'client' */
 213 static void
 214 process_request_identities(SocketEntry *e, int version)
 215 {
 216         Idtab *tab = idtab_lookup(version);
 217         Identity *id;
 218         Buffer msg;
 219
 220         buffer_init(&msg);
 221         buffer_put_char(&msg, (version == 1) ?
 222             SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
 223         buffer_put_int(&msg, tab->nentries);
 224         TAILQ_FOREACH(id, &tab->idlist, next) {
 225                 if (id->key->type == KEY_RSA1) {
 226                         buffer_put_int(&msg, BN_num_bits(id->key->rsa->n));
 227                         buffer_put_bignum(&msg, id->key->rsa->e);
 228                         buffer_put_bignum(&msg, id->key->rsa->n);
 229                 } else {
 230                         u_char *blob;
 231                         u_int blen;
 232                         key_to_blob(id->key, &blob, &blen);
 233                         buffer_put_string(&msg, blob, blen);
 234                         xfree(blob);
 235                 }
 236                 buffer_put_cstring(&msg, id->comment);
 237         }
 238         buffer_put_int(&e->output, buffer_len(&msg));
 239         buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
 240         buffer_free(&msg);
 241 }
 242
 243 /* ssh1 only */
 244 static void
 245 process_authentication_challenge1(SocketEntry *e)
 246 {
 247         u_char buf[32], mdbuf[16], session_id[16];
 248         u_int response_type;
 249         BIGNUM *challenge;
 250         Identity *id;
 251         int i, len;
 252         Buffer msg;
 253         MD5_CTX md;
 254         Key *key;
 255
 256         buffer_init(&msg);
 257         key = key_new(KEY_RSA1);
 258         if ((challenge = BN_new()) == NULL)
 259                 fatal("process_authentication_challenge1: BN_new failed");
 260
 261         (void) buffer_get_int(&e->request);                     /* ignored */
 262         buffer_get_bignum(&e->request, key->rsa->e);
 263         buffer_get_bignum(&e->request, key->rsa->n);
 264         buffer_get_bignum(&e->request, challenge);
 265
 266         /* Only protocol 1.1 is supported */
 267         if (buffer_len(&e->request) == 0)
 268                 goto failure;
 269         buffer_get(&e->request, session_id, 16);
 270         response_type = buffer_get_int(&e->request);
 271         if (response_type != 1)
 272                 goto failure;
 273
 274         id = lookup_identity(key, 1);
 275         if (id != NULL && (!id->confirm || confirm_key(id) == 0)) {
 276                 Key *private = id->key;
 277                 /* Decrypt the challenge using the private key. */
 278                 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0)
 279                         goto failure;
 280
 281                 /* The response is MD5 of decrypted challenge plus session id. */
 282                 len = BN_num_bytes(challenge);
 283                 if (len <= 0 || len > 32) {
 284                         logit("process_authentication_challenge: bad challenge length %d", len);
 285                         goto failure;
 286                 }
 287                 memset(buf, 0, 32);
 288                 BN_bn2bin(challenge, buf + 32 - len);
 289                 MD5_Init(&md);
 290                 MD5_Update(&md, buf, 32);
 291                 MD5_Update(&md, session_id, 16);
 292                 MD5_Final(mdbuf, &md);
 293
 294                 /* Send the response. */
 295                 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE);
 296                 for (i = 0; i < 16; i++)
 297                         buffer_put_char(&msg, mdbuf[i]);
 298                 goto send;
 299         }
 300
 301 failure:
 302         /* Unknown identity or protocol error.  Send failure. */
 303         buffer_put_char(&msg, SSH_AGENT_FAILURE);
 304 send:
 305         buffer_put_int(&e->output, buffer_len(&msg));
 306         buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
 307         key_free(key);
 308         BN_clear_free(challenge);
 309         buffer_free(&msg);
 310 }
 311
 312 /* ssh2 only */
 313 static void
 314 process_sign_request2(SocketEntry *e)
 315 {
 316         u_char *blob, *data, *signature = NULL;
 317         u_int blen, dlen, slen = 0;
 318         extern int datafellows;
 319         int odatafellows;
 320         int ok = -1, flags;
 321         Buffer msg;
 322         Key *key;
 323
 324         datafellows = 0;
 325
 326         blob = buffer_get_string(&e->request, &blen);
 327         data = buffer_get_string(&e->request, &dlen);
 328
 329         flags = buffer_get_int(&e->request);
 330         odatafellows = datafellows;
 331         if (flags & SSH_AGENT_OLD_SIGNATURE)
 332                 datafellows = SSH_BUG_SIGBLOB;
 333
 334         key = key_from_blob(blob, blen);
 335         if (key != NULL) {
 336                 Identity *id = lookup_identity(key, 2);
 337                 if (id != NULL && (!id->confirm || confirm_key(id) == 0))
 338                         ok = key_sign(id->key, &signature, &slen, data, dlen);
 339                 key_free(key);
 340         }
 341         buffer_init(&msg);
 342         if (ok == 0) {
 343                 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE);
 344                 buffer_put_string(&msg, signature, slen);
 345         } else {
 346                 buffer_put_char(&msg, SSH_AGENT_FAILURE);
 347         }
 348         buffer_put_int(&e->output, buffer_len(&msg));
 349         buffer_append(&e->output, buffer_ptr(&msg),
 350             buffer_len(&msg));
 351         buffer_free(&msg);
 352         xfree(data);
 353         xfree(blob);
 354         if (signature != NULL)
 355                 xfree(signature);
 356         datafellows = odatafellows;
 357 }
 358
 359 /* shared */
 360 static void
 361 process_remove_identity(SocketEntry *e, int version)
 362 {
 363         u_int blen, bits;
 364         int success = 0;
 365         Key *key = NULL;
 366         u_char *blob;
 367
 368         switch (version) {
 369         case 1:
 370                 key = key_new(KEY_RSA1);
 371                 bits = buffer_get_int(&e->request);
 372                 buffer_get_bignum(&e->request, key->rsa->e);
 373                 buffer_get_bignum(&e->request, key->rsa->n);
 374
 375                 if (bits != key_size(key))
 376                         logit("Warning: identity keysize mismatch: actual %u, announced %u",
 377                             key_size(key), bits);
 378                 break;
 379         case 2:
 380                 blob = buffer_get_string(&e->request, &blen);
 381                 key = key_from_blob(blob, blen);
 382                 xfree(blob);
 383                 break;
 384         }
 385         if (key != NULL) {
 386                 Identity *id = lookup_identity(key, version);
 387                 if (id != NULL) {
 388                         /*
 389                          * We have this key.  Free the old key.  Since we
 390                          * don't want to leave empty slots in the middle of
 391                          * the array, we actually free the key there and move
 392                          * all the entries between the empty slot and the end
 393                          * of the array.
 394                          */
 395                         Idtab *tab = idtab_lookup(version);
 396                         if (tab->nentries < 1)
 397                                 fatal("process_remove_identity: "
 398                                     "internal error: tab->nentries %d",
 399                                     tab->nentries);
 400                         TAILQ_REMOVE(&tab->idlist, id, next);
 401                         free_identity(id);
 402                         tab->nentries--;
 403                         success = 1;
 404                 }
 405                 key_free(key);
 406         }
 407         buffer_put_int(&e->output, 1);
 408         buffer_put_char(&e->output,
 409             success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
 410 }
 411
 412 static void
 413 process_remove_all_identities(SocketEntry *e, int version)
 414 {
 415         Idtab *tab = idtab_lookup(version);
 416         Identity *id;
 417
 418         /* Loop over all identities and clear the keys. */
 419         for (id = TAILQ_FIRST(&tab->idlist); id;
 420             id = TAILQ_FIRST(&tab->idlist)) {
 421                 TAILQ_REMOVE(&tab->idlist, id, next);
 422                 free_identity(id);
 423         }
 424
 425         /* Mark that there are no identities. */
 426         tab->nentries = 0;
 427
 428         /* Send success. */
 429         buffer_put_int(&e->output, 1);
 430         buffer_put_char(&e->output, SSH_AGENT_SUCCESS);
 431 }
 432
 433 /* removes expired keys and returns number of seconds until the next expiry */
 434 static u_int
 435 reaper(void)
 436 {
 437         u_int deadline = 0, now = time(NULL);
 438         Identity *id, *nxt;
 439         int version;
 440         Idtab *tab;
 441
 442         for (version = 1; version < 3; version++) {
 443                 tab = idtab_lookup(version);
 444                 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) {
 445                         nxt = TAILQ_NEXT(id, next);
 446                         if (id->death == 0)
 447                                 continue;
 448                         if (now >= id->death) {
 449                                 debug("expiring key '%s'", id->comment);
 450                                 TAILQ_REMOVE(&tab->idlist, id, next);
 451                                 free_identity(id);
 452                                 tab->nentries--;
 453                         } else
 454                                 deadline = (deadline == 0) ? id->death :
 455                                     MIN(deadline, id->death);
 456                 }
 457         }
 458         if (deadline == 0 || deadline <= now)
 459                 return 0;
 460         else
 461                 return (deadline - now);
 462 }
 463
 464 static void
 465 process_add_identity(SocketEntry *e, int version)
 466 {
 467         Idtab *tab = idtab_lookup(version);
 468         Identity *id;
 469         int type, success = 0, death = 0, confirm = 0;
 470         char *type_name, *comment;
 471         Key *k = NULL;
 472         u_char *cert;
 473         u_int len;
 474
 475         switch (version) {
 476         case 1:
 477                 k = key_new_private(KEY_RSA1);
 478                 (void) buffer_get_int(&e->request);             /* ignored */
 479                 buffer_get_bignum(&e->request, k->rsa->n);
 480                 buffer_get_bignum(&e->request, k->rsa->e);
 481                 buffer_get_bignum(&e->request, k->rsa->d);
 482                 buffer_get_bignum(&e->request, k->rsa->iqmp);
 483
 484                 /* SSH and SSL have p and q swapped */
 485                 buffer_get_bignum(&e->request, k->rsa->q);      /* p */
 486                 buffer_get_bignum(&e->request, k->rsa->p);      /* q */
 487
 488                 /* Generate additional parameters */
 489                 rsa_generate_additional_parameters(k->rsa);
 490                 break;
 491         case 2:
 492                 type_name = buffer_get_string(&e->request, NULL);
 493                 type = key_type_from_name(type_name);
 494                 xfree(type_name);
 495                 switch (type) {
 496                 case KEY_DSA:
 497                         k = key_new_private(type);
 498                         buffer_get_bignum2(&e->request, k->dsa->p);
 499                         buffer_get_bignum2(&e->request, k->dsa->q);
 500                         buffer_get_bignum2(&e->request, k->dsa->g);
 501                         buffer_get_bignum2(&e->request, k->dsa->pub_key);
 502                         buffer_get_bignum2(&e->request, k->dsa->priv_key);
 503                         break;
 504                 case KEY_DSA_CERT_V00:
 505                 case KEY_DSA_CERT:
 506                         cert = buffer_get_string(&e->request, &len);
 507                         if ((k = key_from_blob(cert, len)) == NULL)
 508                                 fatal("Certificate parse failed");
 509                         xfree(cert);
 510                         key_add_private(k);
 511                         buffer_get_bignum2(&e->request, k->dsa->priv_key);
 512                         break;
 513                 case KEY_RSA:
 514                         k = key_new_private(type);
 515                         buffer_get_bignum2(&e->request, k->rsa->n);
 516                         buffer_get_bignum2(&e->request, k->rsa->e);
 517                         buffer_get_bignum2(&e->request, k->rsa->d);
 518                         buffer_get_bignum2(&e->request, k->rsa->iqmp);
 519                         buffer_get_bignum2(&e->request, k->rsa->p);
 520                         buffer_get_bignum2(&e->request, k->rsa->q);
 521
 522                         /* Generate additional parameters */
 523                         rsa_generate_additional_parameters(k->rsa);
 524                         break;
 525                 case KEY_RSA_CERT_V00:
 526                 case KEY_RSA_CERT:
 527                         cert = buffer_get_string(&e->request, &len);
 528                         if ((k = key_from_blob(cert, len)) == NULL)
 529                                 fatal("Certificate parse failed");
 530                         xfree(cert);
 531                         key_add_private(k);
 532                         buffer_get_bignum2(&e->request, k->rsa->d);
 533                         buffer_get_bignum2(&e->request, k->rsa->iqmp);
 534                         buffer_get_bignum2(&e->request, k->rsa->p);
 535                         buffer_get_bignum2(&e->request, k->rsa->q);
 536                         break;
 537                 default:
 538                         buffer_clear(&e->request);
 539                         goto send;
 540                 }
 541                 break;
 542         }
 543         /* enable blinding */
 544         switch (k->type) {
 545         case KEY_RSA:
 546         case KEY_RSA_CERT_V00:
 547         case KEY_RSA_CERT:
 548         case KEY_RSA1:
 549                 if (RSA_blinding_on(k->rsa, NULL) != 1) {
 550                         error("process_add_identity: RSA_blinding_on failed");
 551                         key_free(k);
 552                         goto send;
 553                 }
 554                 break;
 555         }
 556         comment = buffer_get_string(&e->request, NULL);
 557         if (k == NULL) {
 558                 xfree(comment);
 559                 goto send;
 560         }
 561         while (buffer_len(&e->request)) {
 562                 switch ((type = buffer_get_char(&e->request))) {
 563                 case SSH_AGENT_CONSTRAIN_LIFETIME:
 564                         death = time(NULL) + buffer_get_int(&e->request);
 565                         break;
 566                 case SSH_AGENT_CONSTRAIN_CONFIRM:
 567                         confirm = 1;
 568                         break;
 569                 default:
 570                         error("process_add_identity: "
 571                             "Unknown constraint type %d", type);
 572                         xfree(comment);
 573                         key_free(k);
 574                         goto send;
 575                 }
 576         }
 577         success = 1;
 578         if (lifetime && !death)
 579                 death = time(NULL) + lifetime;
 580         if ((id = lookup_identity(k, version)) == NULL) {
 581                 id = xcalloc(1, sizeof(Identity));
 582                 id->key = k;
 583                 TAILQ_INSERT_TAIL(&tab->idlist, id, next);
 584                 /* Increment the number of identities. */
 585                 tab->nentries++;
 586         } else {
 587                 key_free(k);
 588                 xfree(id->comment);
 589         }
 590         id->comment = comment;
 591         id->death = death;
 592         id->confirm = confirm;
 593 send:
 594         buffer_put_int(&e->output, 1);
 595         buffer_put_char(&e->output,
 596             success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
 597 }
 598
 599 /* XXX todo: encrypt sensitive data with passphrase */
 600 static void
 601 process_lock_agent(SocketEntry *e, int lock)
 602 {
 603         int success = 0;
 604         char *passwd;
 605
 606         passwd = buffer_get_string(&e->request, NULL);
 607         if (locked && !lock && strcmp(passwd, lock_passwd) == 0) {
 608                 locked = 0;
 609                 memset(lock_passwd, 0, strlen(lock_passwd));
 610                 xfree(lock_passwd);
 611                 lock_passwd = NULL;
 612                 success = 1;
 613         } else if (!locked && lock) {
 614                 locked = 1;
 615                 lock_passwd = xstrdup(passwd);
 616                 success = 1;
 617         }
 618         memset(passwd, 0, strlen(passwd));
 619         xfree(passwd);
 620
 621         buffer_put_int(&e->output, 1);
 622         buffer_put_char(&e->output,
 623             success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
 624 }
 625
 626 static void
 627 no_identities(SocketEntry *e, u_int type)
 628 {
 629         Buffer msg;
 630
 631         buffer_init(&msg);
 632         buffer_put_char(&msg,
 633             (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ?
 634             SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
 635         buffer_put_int(&msg, 0);
 636         buffer_put_int(&e->output, buffer_len(&msg));
 637         buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
 638         buffer_free(&msg);
 639 }
 640
 641 #ifdef ENABLE_PKCS11
 642 static void
 643 process_add_smartcard_key(SocketEntry *e)
 644 {
 645         char *provider = NULL, *pin;
 646         int i, type, version, count = 0, success = 0, death = 0, confirm = 0;
 647         Key **keys = NULL, *k;
 648         Identity *id;
 649         Idtab *tab;
 650
 651         provider = buffer_get_string(&e->request, NULL);
 652         pin = buffer_get_string(&e->request, NULL);
 653
 654         while (buffer_len(&e->request)) {
 655                 switch ((type = buffer_get_char(&e->request))) {
 656                 case SSH_AGENT_CONSTRAIN_LIFETIME:
 657                         death = time(NULL) + buffer_get_int(&e->request);
 658                         break;
 659                 case SSH_AGENT_CONSTRAIN_CONFIRM:
 660                         confirm = 1;
 661                         break;
 662                 default:
 663                         error("process_add_smartcard_key: "
 664                             "Unknown constraint type %d", type);
 665                         goto send;
 666                 }
 667         }
 668         if (lifetime && !death)
 669                 death = time(NULL) + lifetime;
 670
 671         count = pkcs11_add_provider(provider, pin, &keys);
 672         for (i = 0; i < count; i++) {
 673                 k = keys[i];
 674                 version = k->type == KEY_RSA1 ? 1 : 2;
 675                 tab = idtab_lookup(version);
 676                 if (lookup_identity(k, version) == NULL) {
 677                         id = xcalloc(1, sizeof(Identity));
 678                         id->key = k;
 679                         id->provider = xstrdup(provider);
 680                         id->comment = xstrdup(provider); /* XXX */
 681                         id->death = death;
 682                         id->confirm = confirm;
 683                         TAILQ_INSERT_TAIL(&tab->idlist, id, next);
 684                         tab->nentries++;
 685                         success = 1;
 686                 } else {
 687                         key_free(k);
 688                 }
 689                 keys[i] = NULL;
 690         }
 691 send:
 692         if (pin)
 693                 xfree(pin);
 694         if (provider)
 695                 xfree(provider);
 696         if (keys)
 697                 xfree(keys);
 698         buffer_put_int(&e->output, 1);
 699         buffer_put_char(&e->output,
 700             success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
 701 }
 702
 703 static void
 704 process_remove_smartcard_key(SocketEntry *e)
 705 {
 706         char *provider = NULL, *pin = NULL;
 707         int version, success = 0;
 708         Identity *id, *nxt;
 709         Idtab *tab;
 710
 711         provider = buffer_get_string(&e->request, NULL);
 712         pin = buffer_get_string(&e->request, NULL);
 713         xfree(pin);
 714
 715         for (version = 1; version < 3; version++) {
 716                 tab = idtab_lookup(version);
 717                 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) {
 718                         nxt = TAILQ_NEXT(id, next);
 719                         if (!strcmp(provider, id->provider)) {
 720                                 TAILQ_REMOVE(&tab->idlist, id, next);
 721                                 free_identity(id);
 722                                 tab->nentries--;
 723                         }
 724                 }
 725         }
 726         if (pkcs11_del_provider(provider) == 0)
 727                 success = 1;
 728         else
 729                 error("process_remove_smartcard_key:"
 730                     " pkcs11_del_provider failed");
 731         xfree(provider);
 732         buffer_put_int(&e->output, 1);
 733         buffer_put_char(&e->output,
 734             success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
 735 }
 736 #endif /* ENABLE_PKCS11 */
 737
 738 /* dispatch incoming messages */
 739
 740 static void
 741 process_message(SocketEntry *e)
 742 {
 743         u_int msg_len, type;
 744         u_char *cp;
 745
 746         if (buffer_len(&e->input) < 5)
 747                 return;         /* Incomplete message. */
 748         cp = buffer_ptr(&e->input);
 749         msg_len = get_u32(cp);
 750         if (msg_len > 256 * 1024) {
 751                 close_socket(e);
 752                 return;
 753         }
 754         if (buffer_len(&e->input) < msg_len + 4)
 755                 return;
 756
 757         /* move the current input to e->request */
 758         buffer_consume(&e->input, 4);
 759         buffer_clear(&e->request);
 760         buffer_append(&e->request, buffer_ptr(&e->input), msg_len);
 761         buffer_consume(&e->input, msg_len);
 762         type = buffer_get_char(&e->request);
 763
 764         /* check wheter agent is locked */
 765         if (locked && type != SSH_AGENTC_UNLOCK) {
 766                 buffer_clear(&e->request);
 767                 switch (type) {
 768                 case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
 769                 case SSH2_AGENTC_REQUEST_IDENTITIES:
 770                         /* send empty lists */
 771                         no_identities(e, type);
 772                         break;
 773                 default:
 774                         /* send a fail message for all other request types */
 775                         buffer_put_int(&e->output, 1);
 776                         buffer_put_char(&e->output, SSH_AGENT_FAILURE);
 777                 }
 778                 return;
 779         }
 780
 781         debug("type %d", type);
 782         switch (type) {
 783         case SSH_AGENTC_LOCK:
 784         case SSH_AGENTC_UNLOCK:
 785                 process_lock_agent(e, type == SSH_AGENTC_LOCK);
 786                 break;
 787         /* ssh1 */
 788         case SSH_AGENTC_RSA_CHALLENGE:
 789                 process_authentication_challenge1(e);
 790                 break;
 791         case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
 792                 process_request_identities(e, 1);
 793                 break;
 794         case SSH_AGENTC_ADD_RSA_IDENTITY:
 795         case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED:
 796                 process_add_identity(e, 1);
 797                 break;
 798         case SSH_AGENTC_REMOVE_RSA_IDENTITY:
 799                 process_remove_identity(e, 1);
 800                 break;
 801         case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
 802                 process_remove_all_identities(e, 1);
 803                 break;
 804         /* ssh2 */
 805         case SSH2_AGENTC_SIGN_REQUEST:
 806                 process_sign_request2(e);
 807                 break;
 808         case SSH2_AGENTC_REQUEST_IDENTITIES:
 809                 process_request_identities(e, 2);
 810                 break;
 811         case SSH2_AGENTC_ADD_IDENTITY:
 812         case SSH2_AGENTC_ADD_ID_CONSTRAINED:
 813                 process_add_identity(e, 2);
 814                 break;
 815         case SSH2_AGENTC_REMOVE_IDENTITY:
 816                 process_remove_identity(e, 2);
 817                 break;
 818         case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
 819                 process_remove_all_identities(e, 2);
 820                 break;
 821 #ifdef ENABLE_PKCS11
 822         case SSH_AGENTC_ADD_SMARTCARD_KEY:
 823         case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED:
 824                 process_add_smartcard_key(e);
 825                 break;
 826         case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
 827                 process_remove_smartcard_key(e);
 828                 break;
 829 #endif /* ENABLE_PKCS11 */
 830         default:
 831                 /* Unknown message.  Respond with failure. */
 832                 error("Unknown message %d", type);
 833                 buffer_clear(&e->request);
 834                 buffer_put_int(&e->output, 1);
 835                 buffer_put_char(&e->output, SSH_AGENT_FAILURE);
 836                 break;
 837         }
 838 }
 839
 840 static void
 841 new_socket(sock_type type, int fd)
 842 {
 843         u_int i, old_alloc, new_alloc;
 844
 845         set_nonblock(fd);
 846
 847         if (fd > max_fd)
 848                 max_fd = fd;
 849
 850         for (i = 0; i < sockets_alloc; i++)
 851                 if (sockets[i].type == AUTH_UNUSED) {
 852                         sockets[i].fd = fd;
 853                         buffer_init(&sockets[i].input);
 854                         buffer_init(&sockets[i].output);
 855                         buffer_init(&sockets[i].request);
 856                         sockets[i].type = type;
 857                         return;
 858                 }
 859         old_alloc = sockets_alloc;
 860         new_alloc = sockets_alloc + 10;
 861         sockets = xrealloc(sockets, new_alloc, sizeof(sockets[0]));
 862         for (i = old_alloc; i < new_alloc; i++)
 863                 sockets[i].type = AUTH_UNUSED;
 864         sockets_alloc = new_alloc;
 865         sockets[old_alloc].fd = fd;
 866         buffer_init(&sockets[old_alloc].input);
 867         buffer_init(&sockets[old_alloc].output);
 868         buffer_init(&sockets[old_alloc].request);
 869         sockets[old_alloc].type = type;
 870 }
 871
 872 static int
 873 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp,
 874     struct timeval **tvpp)
 875 {
 876         u_int i, sz, deadline;
 877         int n = 0;
 878         static struct timeval tv;
 879
 880         for (i = 0; i < sockets_alloc; i++) {
 881                 switch (sockets[i].type) {
 882                 case AUTH_SOCKET:
 883                 case AUTH_CONNECTION:
 884                         n = MAX(n, sockets[i].fd);
 885                         break;
 886                 case AUTH_UNUSED:
 887                         break;
 888                 default:
 889                         fatal("Unknown socket type %d", sockets[i].type);
 890                         break;
 891                 }
 892         }
 893
 894         sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
 895         if (*fdrp == NULL || sz > *nallocp) {
 896                 if (*fdrp)
 897                         xfree(*fdrp);
 898                 if (*fdwp)
 899                         xfree(*fdwp);
 900                 *fdrp = xmalloc(sz);
 901                 *fdwp = xmalloc(sz);
 902                 *nallocp = sz;
 903         }
 904         if (n < *fdl)
 905                 debug("XXX shrink: %d < %d", n, *fdl);
 906         *fdl = n;
 907         memset(*fdrp, 0, sz);
 908         memset(*fdwp, 0, sz);
 909
 910         for (i = 0; i < sockets_alloc; i++) {
 911                 switch (sockets[i].type) {
 912                 case AUTH_SOCKET:
 913                 case AUTH_CONNECTION:
 914                         FD_SET(sockets[i].fd, *fdrp);
 915                         if (buffer_len(&sockets[i].output) > 0)
 916                                 FD_SET(sockets[i].fd, *fdwp);
 917                         break;
 918                 default:
 919                         break;
 920                 }
 921         }
 922         deadline = reaper();
 923         if (parent_alive_interval != 0)
 924                 deadline = (deadline == 0) ? parent_alive_interval :
 925                     MIN(deadline, parent_alive_interval);
 926         if (deadline == 0) {
 927                 *tvpp = NULL;
 928         } else {
 929                 tv.tv_sec = deadline;
 930                 tv.tv_usec = 0;
 931                 *tvpp = &tv;
 932         }
 933         return (1);
 934 }
 935
 936 static void
 937 after_select(fd_set *readset, fd_set *writeset)
 938 {
 939         struct sockaddr_un sunaddr;
 940         socklen_t slen;
 941         char buf[1024];
 942         int len, sock;
 943         u_int i, orig_alloc;
 944         uid_t euid;
 945         gid_t egid;
 946
 947         for (i = 0, orig_alloc = sockets_alloc; i < orig_alloc; i++)
 948                 switch (sockets[i].type) {
 949                 case AUTH_UNUSED:
 950                         break;
 951                 case AUTH_SOCKET:
 952                         if (FD_ISSET(sockets[i].fd, readset)) {
 953                                 slen = sizeof(sunaddr);
 954                                 sock = accept(sockets[i].fd,
 955                                     (struct sockaddr *)&sunaddr, &slen);
 956                                 if (sock < 0) {
 957                                         error("accept from AUTH_SOCKET: %s",
 958                                             strerror(errno));
 959                                         break;
 960                                 }
 961                                 if (getpeereid(sock, &euid, &egid) < 0) {
 962                                         error("getpeereid %d failed: %s",
 963                                             sock, strerror(errno));
 964                                         close(sock);
 965                                         break;
 966                                 }
 967                                 if ((euid != 0) && (getuid() != euid)) {
 968                                         error("uid mismatch: "
 969                                             "peer euid %u != uid %u",
 970                                             (u_int) euid, (u_int) getuid());
 971                                         close(sock);
 972                                         break;
 973                                 }
 974                                 new_socket(AUTH_CONNECTION, sock);
 975                         }
 976                         break;
 977                 case AUTH_CONNECTION:
 978                         if (buffer_len(&sockets[i].output) > 0 &&
 979                             FD_ISSET(sockets[i].fd, writeset)) {
 980                                 len = write(sockets[i].fd,
 981                                     buffer_ptr(&sockets[i].output),
 982                                     buffer_len(&sockets[i].output));
 983                                 if (len == -1 && (errno == EAGAIN ||
 984                                     errno == EWOULDBLOCK ||
 985                                     errno == EINTR))
 986                                         continue;
 987                                 if (len <= 0) {
 988                                         close_socket(&sockets[i]);
 989                                         break;
 990                                 }
 991                                 buffer_consume(&sockets[i].output, len);
 992                         }
 993                         if (FD_ISSET(sockets[i].fd, readset)) {
 994                                 len = read(sockets[i].fd, buf, sizeof(buf));
 995                                 if (len == -1 && (errno == EAGAIN ||
 996                                     errno == EWOULDBLOCK ||
 997                                     errno == EINTR))
 998                                         continue;
 999                                 if (len <= 0) {
1000                                         close_socket(&sockets[i]);
1001                                         break;
1002                                 }
1003                                 buffer_append(&sockets[i].input, buf, len);
1004                                 process_message(&sockets[i]);
1005                         }
1006                         break;
1007                 default:
1008                         fatal("Unknown type %d", sockets[i].type);
1009                 }
1010 }
1011
1012 static void
1013 cleanup_socket(void)
1014 {
1015         if (socket_name[0])
1016                 unlink(socket_name);
1017         if (socket_dir[0])
1018                 rmdir(socket_dir);
1019 }
1020
1021 void
1022 cleanup_exit(int i)
1023 {
1024         cleanup_socket();
1025         _exit(i);
1026 }
1027
1028 /*ARGSUSED*/
1029 static void
1030 cleanup_handler(int sig)
1031 {
1032         cleanup_socket();
1033 #ifdef ENABLE_PKCS11
1034         pkcs11_terminate();
1035 #endif
1036         _exit(2);
1037 }
1038
1039 static void
1040 check_parent_exists(void)
1041 {
1042         if (parent_pid != -1 && kill(parent_pid, 0) < 0) {
1043                 /* printf("Parent has died - Authentication agent exiting.\n"); */
1044                 cleanup_socket();
1045                 _exit(2);
1046         }
1047 }
1048
1049 static void
1050 usage(void)
1051 {
1052         fprintf(stderr, "usage: %s [options] [command [arg ...]]\n",
1053             __progname);
1054         fprintf(stderr, "Options:\n");
1055         fprintf(stderr, "  -c          Generate C-shell commands on stdout.\n");
1056         fprintf(stderr, "  -s          Generate Bourne shell commands on stdout.\n");
1057         fprintf(stderr, "  -k          Kill the current agent.\n");
1058         fprintf(stderr, "  -d          Debug mode.\n");
1059         fprintf(stderr, "  -a socket   Bind agent socket to given name.\n");
1060         fprintf(stderr, "  -t life     Default identity lifetime (seconds).\n");
1061         exit(1);
1062 }
1063
1064 int
1065 main(int ac, char **av)
1066 {
1067         int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0;
1068         int sock, fd, ch, result, saved_errno;
1069         u_int nalloc;
1070         char *shell, *format, *pidstr, *agentsocket = NULL;
1071         fd_set *readsetp = NULL, *writesetp = NULL;
1072         struct sockaddr_un sunaddr;
1073 #ifdef HAVE_SETRLIMIT
1074         struct rlimit rlim;
1075 #endif
1076         int prev_mask;
1077         extern int optind;
1078         extern char *optarg;
1079         pid_t pid;
1080         char pidstrbuf[1 + 3 * sizeof pid];
1081         struct timeval *tvp = NULL;
1082         size_t len;
1083
1084         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1085         sanitise_stdfd();
1086
1087         /* drop */
1088         setegid(getgid());
1089         setgid(getgid());
1090         setuid(geteuid());
1091
1092 #if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE)
1093         /* Disable ptrace on Linux without sgid bit */
1094         prctl(PR_SET_DUMPABLE, 0);
1095 #endif
1096
1097         SSLeay_add_all_algorithms();
1098
1099         __progname = ssh_get_progname(av[0]);
1100         init_rng();
1101         seed_rng();
1102
1103         while ((ch = getopt(ac, av, "cdksa:t:")) != -1) {
1104                 switch (ch) {
1105                 case 'c':
1106                         if (s_flag)
1107                                 usage();
1108                         c_flag++;
1109                         break;
1110                 case 'k':
1111                         k_flag++;
1112                         break;
1113                 case 's':
1114                         if (c_flag)
1115                                 usage();
1116                         s_flag++;
1117                         break;
1118                 case 'd':
1119                         if (d_flag)
1120                                 usage();
1121                         d_flag++;
1122                         break;
1123                 case 'a':
1124                         agentsocket = optarg;
1125                         break;
1126                 case 't':
1127                         if ((lifetime = convtime(optarg)) == -1) {
1128                                 fprintf(stderr, "Invalid lifetime\n");
1129                                 usage();
1130                         }
1131                         break;
1132                 default:
1133                         usage();
1134                 }
1135         }
1136         ac -= optind;
1137         av += optind;
1138
1139         if (ac > 0 && (c_flag || k_flag || s_flag || d_flag))
1140                 usage();
1141
1142         if (ac == 0 && !c_flag && !s_flag) {
1143                 shell = getenv("SHELL");
1144                 if (shell != NULL && (len = strlen(shell)) > 2 &&
1145                     strncmp(shell + len - 3, "csh", 3) == 0)
1146                         c_flag = 1;
1147         }
1148         if (k_flag) {
1149                 const char *errstr = NULL;
1150
1151                 pidstr = getenv(SSH_AGENTPID_ENV_NAME);
1152                 if (pidstr == NULL) {
1153                         fprintf(stderr, "%s not set, cannot kill agent\n",
1154                             SSH_AGENTPID_ENV_NAME);
1155                         exit(1);
1156                 }
1157                 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr);
1158                 if (errstr) {
1159                         fprintf(stderr,
1160                             "%s=\"%s\", which is not a good PID: %s\n",
1161                             SSH_AGENTPID_ENV_NAME, pidstr, errstr);
1162                         exit(1);
1163                 }
1164                 if (kill(pid, SIGTERM) == -1) {
1165                         perror("kill");
1166                         exit(1);
1167                 }
1168                 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
1169                 printf(format, SSH_AUTHSOCKET_ENV_NAME);
1170                 printf(format, SSH_AGENTPID_ENV_NAME);
1171                 printf("echo Agent pid %ld killed;\n", (long)pid);
1172                 exit(0);
1173         }
1174         parent_pid = getpid();
1175
1176         if (agentsocket == NULL) {
1177                 /* Create private directory for agent socket */
1178                 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXXXX", sizeof socket_dir);
1179                 if (mkdtemp(socket_dir) == NULL) {
1180                         perror("mkdtemp: private socket dir");
1181                         exit(1);
1182                 }
1183                 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir,
1184                     (long)parent_pid);
1185         } else {
1186                 /* Try to use specified agent socket */
1187                 socket_dir[0] = '\0';
1188                 strlcpy(socket_name, agentsocket, sizeof socket_name);
1189         }
1190
1191         /*
1192          * Create socket early so it will exist before command gets run from
1193          * the parent.
1194          */
1195         sock = socket(AF_UNIX, SOCK_STREAM, 0);
1196         if (sock < 0) {
1197                 perror("socket");
1198                 *socket_name = '\0'; /* Don't unlink any existing file */
1199                 cleanup_exit(1);
1200         }
1201         memset(&sunaddr, 0, sizeof(sunaddr));
1202         sunaddr.sun_family = AF_UNIX;
1203         strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path));
1204         prev_mask = umask(0177);
1205         if (bind(sock, (struct sockaddr *) &sunaddr, sizeof(sunaddr)) < 0) {
1206                 perror("bind");
1207                 *socket_name = '\0'; /* Don't unlink any existing file */
1208                 umask(prev_mask);
1209                 cleanup_exit(1);
1210         }
1211         umask(prev_mask);
1212         if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
1213                 perror("listen");
1214                 cleanup_exit(1);
1215         }
1216
1217         /*
1218          * Fork, and have the parent execute the command, if any, or present
1219          * the socket data.  The child continues as the authentication agent.
1220          */
1221         if (d_flag) {
1222                 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1);
1223                 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1224                 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1225                     SSH_AUTHSOCKET_ENV_NAME);
1226                 printf("echo Agent pid %ld;\n", (long)parent_pid);
1227                 goto skip;
1228         }
1229         pid = fork();
1230         if (pid == -1) {
1231                 perror("fork");
1232                 cleanup_exit(1);
1233         }
1234         if (pid != 0) {         /* Parent - execute the given command. */
1235                 close(sock);
1236                 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid);
1237                 if (ac == 0) {
1238                         format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1239                         printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1240                             SSH_AUTHSOCKET_ENV_NAME);
1241                         printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
1242                             SSH_AGENTPID_ENV_NAME);
1243                         printf("echo Agent pid %ld;\n", (long)pid);
1244                         exit(0);
1245                 }
1246                 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 ||
1247                     setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) {
1248                         perror("setenv");
1249                         exit(1);
1250                 }
1251                 execvp(av[0], av);
1252                 perror(av[0]);
1253                 exit(1);
1254         }
1255         /* child */
1256         log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0);
1257
1258         if (setsid() == -1) {
1259                 error("setsid: %s", strerror(errno));
1260                 cleanup_exit(1);
1261         }
1262
1263         (void)chdir("/");
1264         if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1265                 /* XXX might close listen socket */
1266                 (void)dup2(fd, STDIN_FILENO);
1267                 (void)dup2(fd, STDOUT_FILENO);
1268                 (void)dup2(fd, STDERR_FILENO);
1269                 if (fd > 2)
1270                         close(fd);
1271         }
1272
1273 #ifdef HAVE_SETRLIMIT
1274         /* deny core dumps, since memory contains unencrypted private keys */
1275         rlim.rlim_cur = rlim.rlim_max = 0;
1276         if (setrlimit(RLIMIT_CORE, &rlim) < 0) {
1277                 error("setrlimit RLIMIT_CORE: %s", strerror(errno));
1278                 cleanup_exit(1);
1279         }
1280 #endif
1281
1282 skip:
1283
1284 #ifdef ENABLE_PKCS11
1285         pkcs11_init(0);
1286 #endif
1287         new_socket(AUTH_SOCKET, sock);
1288         if (ac > 0)
1289                 parent_alive_interval = 10;
1290         idtab_init();
1291         if (!d_flag)
1292                 signal(SIGINT, SIG_IGN);
1293         signal(SIGPIPE, SIG_IGN);
1294         signal(SIGHUP, cleanup_handler);
1295         signal(SIGTERM, cleanup_handler);
1296         nalloc = 0;
1297
1298         while (1) {
1299                 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp);
1300                 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp);
1301                 saved_errno = errno;
1302                 if (parent_alive_interval != 0)
1303                         check_parent_exists();
1304                 (void) reaper();        /* remove expired keys */
1305                 if (result < 0) {
1306                         if (saved_errno == EINTR)
1307                                 continue;
1308                         fatal("select: %s", strerror(saved_errno));
1309                 } else if (result > 0)
1310                         after_select(readsetp, writesetp);
1311         }
1312         /* NOTREACHED */
1313 }