ssh-agent.c

   1 /* $OpenBSD: ssh-agent.c,v 1.165 2010/02/26 20:29:54 djm Exp $ */
   2 /*
   3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   5  *                    All rights reserved
   6  * The authentication agent program.
   7  *
   8  * As far as I am concerned, the code I have written for this software
   9  * can be used freely for any purpose.  Any derived versions of this
  10  * software must be clearly marked as such, and if the derived work is
  11  * incompatible with the protocol description in the RFC file, it must be
  12  * called by a name other than "ssh" or "Secure Shell".
  13  *
  14  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  15  *
  16  * Redistribution and use in source and binary forms, with or without
  17  * modification, are permitted provided that the following conditions
  18  * are met:
  19  * 1. Redistributions of source code must retain the above copyright
  20  *    notice, this list of conditions and the following disclaimer.
  21  * 2. Redistributions in binary form must reproduce the above copyright
  22  *    notice, this list of conditions and the following disclaimer in the
  23  *    documentation and/or other materials provided with the distribution.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  26  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  27  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  28  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  29  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  30  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  31  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  32  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  33  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  34  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  35  */
  36
  37 #include "includes.h"
  38
  39 #include <sys/types.h>
  40 #include <sys/param.h>
  41 #include <sys/resource.h>
  42 #include <sys/stat.h>
  43 #include <sys/socket.h>
  44 #ifdef HAVE_SYS_TIME_H
  45 # include <sys/time.h>
  46 #endif
  47 #ifdef HAVE_SYS_UN_H
  48 # include <sys/un.h>
  49 #endif
  50 #include "openbsd-compat/sys-queue.h"
  51
  52 #include <openssl/evp.h>
  53 #include <openssl/md5.h>
  54 #include "openbsd-compat/openssl-compat.h"
  55
  56 #include <errno.h>
  57 #include <fcntl.h>
  58 #ifdef HAVE_PATHS_H
  59 # include <paths.h>
  60 #endif
  61 #include <signal.h>
  62 #include <stdarg.h>
  63 #include <stdio.h>
  64 #include <stdlib.h>
  65 #include <time.h>
  66 #include <string.h>
  67 #include <unistd.h>
  68
  69 #include "xmalloc.h"
  70 #include "ssh.h"
  71 #include "rsa.h"
  72 #include "buffer.h"
  73 #include "key.h"
  74 #include "authfd.h"
  75 #include "compat.h"
  76 #include "log.h"
  77 #include "misc.h"
  78
  79 #ifdef ENABLE_PKCS11
  80 #include "ssh-pkcs11.h"
  81 #endif
  82
  83 #if defined(HAVE_SYS_PRCTL_H)
  84 #include <sys/prctl.h>  /* For prctl() and PR_SET_DUMPABLE */
  85 #endif
  86
  87 typedef enum {
  88         AUTH_UNUSED,
  89         AUTH_SOCKET,
  90         AUTH_CONNECTION
  91 } sock_type;
  92
  93 typedef struct {
  94         int fd;
  95         sock_type type;
  96         Buffer input;
  97         Buffer output;
  98         Buffer request;
  99 } SocketEntry;
 100
 101 u_int sockets_alloc = 0;
 102 SocketEntry *sockets = NULL;
 103
 104 typedef struct identity {
 105         TAILQ_ENTRY(identity) next;
 106         Key *key;
 107         char *comment;
 108         char *provider;
 109         u_int death;
 110         u_int confirm;
 111 } Identity;
 112
 113 typedef struct {
 114         int nentries;
 115         TAILQ_HEAD(idqueue, identity) idlist;
 116 } Idtab;
 117
 118 /* private key table, one per protocol version */
 119 Idtab idtable[3];
 120
 121 int max_fd = 0;
 122
 123 /* pid of shell == parent of agent */
 124 pid_t parent_pid = -1;
 125 u_int parent_alive_interval = 0;
 126
 127 /* pathname and directory for AUTH_SOCKET */
 128 char socket_name[MAXPATHLEN];
 129 char socket_dir[MAXPATHLEN];
 130
 131 /* locking */
 132 int locked = 0;
 133 char *lock_passwd = NULL;
 134
 135 extern char *__progname;
 136
 137 /* Default lifetime (0 == forever) */
 138 static int lifetime = 0;
 139
 140 static void
 141 close_socket(SocketEntry *e)
 142 {
 143         close(e->fd);
 144         e->fd = -1;
 145         e->type = AUTH_UNUSED;
 146         buffer_free(&e->input);
 147         buffer_free(&e->output);
 148         buffer_free(&e->request);
 149 }
 150
 151 static void
 152 idtab_init(void)
 153 {
 154         int i;
 155
 156         for (i = 0; i <=2; i++) {
 157                 TAILQ_INIT(&idtable[i].idlist);
 158                 idtable[i].nentries = 0;
 159         }
 160 }
 161
 162 /* return private key table for requested protocol version */
 163 static Idtab *
 164 idtab_lookup(int version)
 165 {
 166         if (version < 1 || version > 2)
 167                 fatal("internal error, bad protocol version %d", version);
 168         return &idtable[version];
 169 }
 170
 171 static void
 172 free_identity(Identity *id)
 173 {
 174         key_free(id->key);
 175         if (id->provider != NULL)
 176                 xfree(id->provider);
 177         xfree(id->comment);
 178         xfree(id);
 179 }
 180
 181 /* return matching private key for given public key */
 182 static Identity *
 183 lookup_identity(Key *key, int version)
 184 {
 185         Identity *id;
 186
 187         Idtab *tab = idtab_lookup(version);
 188         TAILQ_FOREACH(id, &tab->idlist, next) {
 189                 if (key_equal(key, id->key))
 190                         return (id);
 191         }
 192         return (NULL);
 193 }
 194
 195 /* Check confirmation of keysign request */
 196 static int
 197 confirm_key(Identity *id)
 198 {
 199         char *p;
 200         int ret = -1;
 201
 202         p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX);
 203         if (ask_permission("Allow use of key %s?\nKey fingerprint %s.",
 204             id->comment, p))
 205                 ret = 0;
 206         xfree(p);
 207
 208         return (ret);
 209 }
 210
 211 /* send list of supported public keys to 'client' */
 212 static void
 213 process_request_identities(SocketEntry *e, int version)
 214 {
 215         Idtab *tab = idtab_lookup(version);
 216         Identity *id;
 217         Buffer msg;
 218
 219         buffer_init(&msg);
 220         buffer_put_char(&msg, (version == 1) ?
 221             SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
 222         buffer_put_int(&msg, tab->nentries);
 223         TAILQ_FOREACH(id, &tab->idlist, next) {
 224                 if (id->key->type == KEY_RSA1) {
 225                         buffer_put_int(&msg, BN_num_bits(id->key->rsa->n));
 226                         buffer_put_bignum(&msg, id->key->rsa->e);
 227                         buffer_put_bignum(&msg, id->key->rsa->n);
 228                 } else {
 229                         u_char *blob;
 230                         u_int blen;
 231                         key_to_blob(id->key, &blob, &blen);
 232                         buffer_put_string(&msg, blob, blen);
 233                         xfree(blob);
 234                 }
 235                 buffer_put_cstring(&msg, id->comment);
 236         }
 237         buffer_put_int(&e->output, buffer_len(&msg));
 238         buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
 239         buffer_free(&msg);
 240 }
 241
 242 /* ssh1 only */
 243 static void
 244 process_authentication_challenge1(SocketEntry *e)
 245 {
 246         u_char buf[32], mdbuf[16], session_id[16];
 247         u_int response_type;
 248         BIGNUM *challenge;
 249         Identity *id;
 250         int i, len;
 251         Buffer msg;
 252         MD5_CTX md;
 253         Key *key;
 254
 255         buffer_init(&msg);
 256         key = key_new(KEY_RSA1);
 257         if ((challenge = BN_new()) == NULL)
 258                 fatal("process_authentication_challenge1: BN_new failed");
 259
 260         (void) buffer_get_int(&e->request);                     /* ignored */
 261         buffer_get_bignum(&e->request, key->rsa->e);
 262         buffer_get_bignum(&e->request, key->rsa->n);
 263         buffer_get_bignum(&e->request, challenge);
 264
 265         /* Only protocol 1.1 is supported */
 266         if (buffer_len(&e->request) == 0)
 267                 goto failure;
 268         buffer_get(&e->request, session_id, 16);
 269         response_type = buffer_get_int(&e->request);
 270         if (response_type != 1)
 271                 goto failure;
 272
 273         id = lookup_identity(key, 1);
 274         if (id != NULL && (!id->confirm || confirm_key(id) == 0)) {
 275                 Key *private = id->key;
 276                 /* Decrypt the challenge using the private key. */
 277                 if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0)
 278                         goto failure;
 279
 280                 /* The response is MD5 of decrypted challenge plus session id. */
 281                 len = BN_num_bytes(challenge);
 282                 if (len <= 0 || len > 32) {
 283                         logit("process_authentication_challenge: bad challenge length %d", len);
 284                         goto failure;
 285                 }
 286                 memset(buf, 0, 32);
 287                 BN_bn2bin(challenge, buf + 32 - len);
 288                 MD5_Init(&md);
 289                 MD5_Update(&md, buf, 32);
 290                 MD5_Update(&md, session_id, 16);
 291                 MD5_Final(mdbuf, &md);
 292
 293                 /* Send the response. */
 294                 buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE);
 295                 for (i = 0; i < 16; i++)
 296                         buffer_put_char(&msg, mdbuf[i]);
 297                 goto send;
 298         }
 299
 300 failure:
 301         /* Unknown identity or protocol error.  Send failure. */
 302         buffer_put_char(&msg, SSH_AGENT_FAILURE);
 303 send:
 304         buffer_put_int(&e->output, buffer_len(&msg));
 305         buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
 306         key_free(key);
 307         BN_clear_free(challenge);
 308         buffer_free(&msg);
 309 }
 310
 311 /* ssh2 only */
 312 static void
 313 process_sign_request2(SocketEntry *e)
 314 {
 315         u_char *blob, *data, *signature = NULL;
 316         u_int blen, dlen, slen = 0;
 317         extern int datafellows;
 318         int odatafellows;
 319         int ok = -1, flags;
 320         Buffer msg;
 321         Key *key;
 322
 323         datafellows = 0;
 324
 325         blob = buffer_get_string(&e->request, &blen);
 326         data = buffer_get_string(&e->request, &dlen);
 327
 328         flags = buffer_get_int(&e->request);
 329         odatafellows = datafellows;
 330         if (flags & SSH_AGENT_OLD_SIGNATURE)
 331                 datafellows = SSH_BUG_SIGBLOB;
 332
 333         key = key_from_blob(blob, blen);
 334         if (key != NULL) {
 335                 Identity *id = lookup_identity(key, 2);
 336                 if (id != NULL && (!id->confirm || confirm_key(id) == 0))
 337                         ok = key_sign(id->key, &signature, &slen, data, dlen);
 338                 key_free(key);
 339         }
 340         buffer_init(&msg);
 341         if (ok == 0) {
 342                 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE);
 343                 buffer_put_string(&msg, signature, slen);
 344         } else {
 345                 buffer_put_char(&msg, SSH_AGENT_FAILURE);
 346         }
 347         buffer_put_int(&e->output, buffer_len(&msg));
 348         buffer_append(&e->output, buffer_ptr(&msg),
 349             buffer_len(&msg));
 350         buffer_free(&msg);
 351         xfree(data);
 352         xfree(blob);
 353         if (signature != NULL)
 354                 xfree(signature);
 355         datafellows = odatafellows;
 356 }
 357
 358 /* shared */
 359 static void
 360 process_remove_identity(SocketEntry *e, int version)
 361 {
 362         u_int blen, bits;
 363         int success = 0;
 364         Key *key = NULL;
 365         u_char *blob;
 366
 367         switch (version) {
 368         case 1:
 369                 key = key_new(KEY_RSA1);
 370                 bits = buffer_get_int(&e->request);
 371                 buffer_get_bignum(&e->request, key->rsa->e);
 372                 buffer_get_bignum(&e->request, key->rsa->n);
 373
 374                 if (bits != key_size(key))
 375                         logit("Warning: identity keysize mismatch: actual %u, announced %u",
 376                             key_size(key), bits);
 377                 break;
 378         case 2:
 379                 blob = buffer_get_string(&e->request, &blen);
 380                 key = key_from_blob(blob, blen);
 381                 xfree(blob);
 382                 break;
 383         }
 384         if (key != NULL) {
 385                 Identity *id = lookup_identity(key, version);
 386                 if (id != NULL) {
 387                         /*
 388                          * We have this key.  Free the old key.  Since we
 389                          * don't want to leave empty slots in the middle of
 390                          * the array, we actually free the key there and move
 391                          * all the entries between the empty slot and the end
 392                          * of the array.
 393                          */
 394                         Idtab *tab = idtab_lookup(version);
 395                         if (tab->nentries < 1)
 396                                 fatal("process_remove_identity: "
 397                                     "internal error: tab->nentries %d",
 398                                     tab->nentries);
 399                         TAILQ_REMOVE(&tab->idlist, id, next);
 400                         free_identity(id);
 401                         tab->nentries--;
 402                         success = 1;
 403                 }
 404                 key_free(key);
 405         }
 406         buffer_put_int(&e->output, 1);
 407         buffer_put_char(&e->output,
 408             success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
 409 }
 410
 411 static void
 412 process_remove_all_identities(SocketEntry *e, int version)
 413 {
 414         Idtab *tab = idtab_lookup(version);
 415         Identity *id;
 416
 417         /* Loop over all identities and clear the keys. */
 418         for (id = TAILQ_FIRST(&tab->idlist); id;
 419             id = TAILQ_FIRST(&tab->idlist)) {
 420                 TAILQ_REMOVE(&tab->idlist, id, next);
 421                 free_identity(id);
 422         }
 423
 424         /* Mark that there are no identities. */
 425         tab->nentries = 0;
 426
 427         /* Send success. */
 428         buffer_put_int(&e->output, 1);
 429         buffer_put_char(&e->output, SSH_AGENT_SUCCESS);
 430 }
 431
 432 /* removes expired keys and returns number of seconds until the next expiry */
 433 static u_int
 434 reaper(void)
 435 {
 436         u_int deadline = 0, now = time(NULL);
 437         Identity *id, *nxt;
 438         int version;
 439         Idtab *tab;
 440
 441         for (version = 1; version < 3; version++) {
 442                 tab = idtab_lookup(version);
 443                 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) {
 444                         nxt = TAILQ_NEXT(id, next);
 445                         if (id->death == 0)
 446                                 continue;
 447                         if (now >= id->death) {
 448                                 debug("expiring key '%s'", id->comment);
 449                                 TAILQ_REMOVE(&tab->idlist, id, next);
 450                                 free_identity(id);
 451                                 tab->nentries--;
 452                         } else
 453                                 deadline = (deadline == 0) ? id->death :
 454                                     MIN(deadline, id->death);
 455                 }
 456         }
 457         if (deadline == 0 || deadline <= now)
 458                 return 0;
 459         else
 460                 return (deadline - now);
 461 }
 462
 463 static void
 464 process_add_identity(SocketEntry *e, int version)
 465 {
 466         Idtab *tab = idtab_lookup(version);
 467         Identity *id;
 468         int type, success = 0, death = 0, confirm = 0;
 469         char *type_name, *comment;
 470         Key *k = NULL;
 471         u_char *cert;
 472         u_int len;
 473
 474         switch (version) {
 475         case 1:
 476                 k = key_new_private(KEY_RSA1);
 477                 (void) buffer_get_int(&e->request);             /* ignored */
 478                 buffer_get_bignum(&e->request, k->rsa->n);
 479                 buffer_get_bignum(&e->request, k->rsa->e);
 480                 buffer_get_bignum(&e->request, k->rsa->d);
 481                 buffer_get_bignum(&e->request, k->rsa->iqmp);
 482
 483                 /* SSH and SSL have p and q swapped */
 484                 buffer_get_bignum(&e->request, k->rsa->q);      /* p */
 485                 buffer_get_bignum(&e->request, k->rsa->p);      /* q */
 486
 487                 /* Generate additional parameters */
 488                 rsa_generate_additional_parameters(k->rsa);
 489                 break;
 490         case 2:
 491                 type_name = buffer_get_string(&e->request, NULL);
 492                 type = key_type_from_name(type_name);
 493                 xfree(type_name);
 494                 switch (type) {
 495                 case KEY_DSA:
 496                         k = key_new_private(type);
 497                         buffer_get_bignum2(&e->request, k->dsa->p);
 498                         buffer_get_bignum2(&e->request, k->dsa->q);
 499                         buffer_get_bignum2(&e->request, k->dsa->g);
 500                         buffer_get_bignum2(&e->request, k->dsa->pub_key);
 501                         buffer_get_bignum2(&e->request, k->dsa->priv_key);
 502                         break;
 503                 case KEY_DSA_CERT:
 504                         cert = buffer_get_string(&e->request, &len);
 505                         if ((k = key_from_blob(cert, len)) == NULL)
 506                                 fatal("Certificate parse failed");
 507                         xfree(cert);
 508                         key_add_private(k);
 509                         buffer_get_bignum2(&e->request, k->dsa->priv_key);
 510                         break;
 511                 case KEY_RSA:
 512                         k = key_new_private(type);
 513                         buffer_get_bignum2(&e->request, k->rsa->n);
 514                         buffer_get_bignum2(&e->request, k->rsa->e);
 515                         buffer_get_bignum2(&e->request, k->rsa->d);
 516                         buffer_get_bignum2(&e->request, k->rsa->iqmp);
 517                         buffer_get_bignum2(&e->request, k->rsa->p);
 518                         buffer_get_bignum2(&e->request, k->rsa->q);
 519
 520                         /* Generate additional parameters */
 521                         rsa_generate_additional_parameters(k->rsa);
 522                         break;
 523                 case KEY_RSA_CERT:
 524                         cert = buffer_get_string(&e->request, &len);
 525                         if ((k = key_from_blob(cert, len)) == NULL)
 526                                 fatal("Certificate parse failed");
 527                         xfree(cert);
 528                         key_add_private(k);
 529                         buffer_get_bignum2(&e->request, k->rsa->d);
 530                         buffer_get_bignum2(&e->request, k->rsa->iqmp);
 531                         buffer_get_bignum2(&e->request, k->rsa->p);
 532                         buffer_get_bignum2(&e->request, k->rsa->q);
 533                         break;
 534                 default:
 535                         buffer_clear(&e->request);
 536                         goto send;
 537                 }
 538                 break;
 539         }
 540         /* enable blinding */
 541         switch (k->type) {
 542         case KEY_RSA:
 543         case KEY_RSA_CERT:
 544         case KEY_RSA1:
 545                 if (RSA_blinding_on(k->rsa, NULL) != 1) {
 546                         error("process_add_identity: RSA_blinding_on failed");
 547                         key_free(k);
 548                         goto send;
 549                 }
 550                 break;
 551         }
 552         comment = buffer_get_string(&e->request, NULL);
 553         if (k == NULL) {
 554                 xfree(comment);
 555                 goto send;
 556         }
 557         while (buffer_len(&e->request)) {
 558                 switch ((type = buffer_get_char(&e->request))) {
 559                 case SSH_AGENT_CONSTRAIN_LIFETIME:
 560                         death = time(NULL) + buffer_get_int(&e->request);
 561                         break;
 562                 case SSH_AGENT_CONSTRAIN_CONFIRM:
 563                         confirm = 1;
 564                         break;
 565                 default:
 566                         error("process_add_identity: "
 567                             "Unknown constraint type %d", type);
 568                         xfree(comment);
 569                         key_free(k);
 570                         goto send;
 571                 }
 572         }
 573         success = 1;
 574         if (lifetime && !death)
 575                 death = time(NULL) + lifetime;
 576         if ((id = lookup_identity(k, version)) == NULL) {
 577                 id = xcalloc(1, sizeof(Identity));
 578                 id->key = k;
 579                 TAILQ_INSERT_TAIL(&tab->idlist, id, next);
 580                 /* Increment the number of identities. */
 581                 tab->nentries++;
 582         } else {
 583                 key_free(k);
 584                 xfree(id->comment);
 585         }
 586         id->comment = comment;
 587         id->death = death;
 588         id->confirm = confirm;
 589 send:
 590         buffer_put_int(&e->output, 1);
 591         buffer_put_char(&e->output,
 592             success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
 593 }
 594
 595 /* XXX todo: encrypt sensitive data with passphrase */
 596 static void
 597 process_lock_agent(SocketEntry *e, int lock)
 598 {
 599         int success = 0;
 600         char *passwd;
 601
 602         passwd = buffer_get_string(&e->request, NULL);
 603         if (locked && !lock && strcmp(passwd, lock_passwd) == 0) {
 604                 locked = 0;
 605                 memset(lock_passwd, 0, strlen(lock_passwd));
 606                 xfree(lock_passwd);
 607                 lock_passwd = NULL;
 608                 success = 1;
 609         } else if (!locked && lock) {
 610                 locked = 1;
 611                 lock_passwd = xstrdup(passwd);
 612                 success = 1;
 613         }
 614         memset(passwd, 0, strlen(passwd));
 615         xfree(passwd);
 616
 617         buffer_put_int(&e->output, 1);
 618         buffer_put_char(&e->output,
 619             success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
 620 }
 621
 622 static void
 623 no_identities(SocketEntry *e, u_int type)
 624 {
 625         Buffer msg;
 626
 627         buffer_init(&msg);
 628         buffer_put_char(&msg,
 629             (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ?
 630             SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
 631         buffer_put_int(&msg, 0);
 632         buffer_put_int(&e->output, buffer_len(&msg));
 633         buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
 634         buffer_free(&msg);
 635 }
 636
 637 #ifdef ENABLE_PKCS11
 638 static void
 639 process_add_smartcard_key(SocketEntry *e)
 640 {
 641         char *provider = NULL, *pin;
 642         int i, type, version, count = 0, success = 0, death = 0, confirm = 0;
 643         Key **keys = NULL, *k;
 644         Identity *id;
 645         Idtab *tab;
 646
 647         provider = buffer_get_string(&e->request, NULL);
 648         pin = buffer_get_string(&e->request, NULL);
 649
 650         while (buffer_len(&e->request)) {
 651                 switch ((type = buffer_get_char(&e->request))) {
 652                 case SSH_AGENT_CONSTRAIN_LIFETIME:
 653                         death = time(NULL) + buffer_get_int(&e->request);
 654                         break;
 655                 case SSH_AGENT_CONSTRAIN_CONFIRM:
 656                         confirm = 1;
 657                         break;
 658                 default:
 659                         error("process_add_smartcard_key: "
 660                             "Unknown constraint type %d", type);
 661                         goto send;
 662                 }
 663         }
 664         if (lifetime && !death)
 665                 death = time(NULL) + lifetime;
 666
 667         count = pkcs11_add_provider(provider, pin, &keys);
 668         for (i = 0; i < count; i++) {
 669                 k = keys[i];
 670                 version = k->type == KEY_RSA1 ? 1 : 2;
 671                 tab = idtab_lookup(version);
 672                 if (lookup_identity(k, version) == NULL) {
 673                         id = xcalloc(1, sizeof(Identity));
 674                         id->key = k;
 675                         id->provider = xstrdup(provider);
 676                         id->comment = xstrdup(provider); /* XXX */
 677                         id->death = death;
 678                         id->confirm = confirm;
 679                         TAILQ_INSERT_TAIL(&tab->idlist, id, next);
 680                         tab->nentries++;
 681                         success = 1;
 682                 } else {
 683                         key_free(k);
 684                 }
 685                 keys[i] = NULL;
 686         }
 687 send:
 688         if (pin)
 689                 xfree(pin);
 690         if (provider)
 691                 xfree(provider);
 692         if (keys)
 693                 xfree(keys);
 694         buffer_put_int(&e->output, 1);
 695         buffer_put_char(&e->output,
 696             success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
 697 }
 698
 699 static void
 700 process_remove_smartcard_key(SocketEntry *e)
 701 {
 702         char *provider = NULL, *pin = NULL;
 703         int version, success = 0;
 704         Identity *id, *nxt;
 705         Idtab *tab;
 706
 707         provider = buffer_get_string(&e->request, NULL);
 708         pin = buffer_get_string(&e->request, NULL);
 709         xfree(pin);
 710
 711         for (version = 1; version < 3; version++) {
 712                 tab = idtab_lookup(version);
 713                 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) {
 714                         nxt = TAILQ_NEXT(id, next);
 715                         if (!strcmp(provider, id->provider)) {
 716                                 TAILQ_REMOVE(&tab->idlist, id, next);
 717                                 free_identity(id);
 718                                 tab->nentries--;
 719                         }
 720                 }
 721         }
 722         if (pkcs11_del_provider(provider) == 0)
 723                 success = 1;
 724         else
 725                 error("process_remove_smartcard_key:"
 726                     " pkcs11_del_provider failed");
 727         xfree(provider);
 728         buffer_put_int(&e->output, 1);
 729         buffer_put_char(&e->output,
 730             success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
 731 }
 732 #endif /* ENABLE_PKCS11 */
 733
 734 /* dispatch incoming messages */
 735
 736 static void
 737 process_message(SocketEntry *e)
 738 {
 739         u_int msg_len, type;
 740         u_char *cp;
 741
 742         if (buffer_len(&e->input) < 5)
 743                 return;         /* Incomplete message. */
 744         cp = buffer_ptr(&e->input);
 745         msg_len = get_u32(cp);
 746         if (msg_len > 256 * 1024) {
 747                 close_socket(e);
 748                 return;
 749         }
 750         if (buffer_len(&e->input) < msg_len + 4)
 751                 return;
 752
 753         /* move the current input to e->request */
 754         buffer_consume(&e->input, 4);
 755         buffer_clear(&e->request);
 756         buffer_append(&e->request, buffer_ptr(&e->input), msg_len);
 757         buffer_consume(&e->input, msg_len);
 758         type = buffer_get_char(&e->request);
 759
 760         /* check wheter agent is locked */
 761         if (locked && type != SSH_AGENTC_UNLOCK) {
 762                 buffer_clear(&e->request);
 763                 switch (type) {
 764                 case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
 765                 case SSH2_AGENTC_REQUEST_IDENTITIES:
 766                         /* send empty lists */
 767                         no_identities(e, type);
 768                         break;
 769                 default:
 770                         /* send a fail message for all other request types */
 771                         buffer_put_int(&e->output, 1);
 772                         buffer_put_char(&e->output, SSH_AGENT_FAILURE);
 773                 }
 774                 return;
 775         }
 776
 777         debug("type %d", type);
 778         switch (type) {
 779         case SSH_AGENTC_LOCK:
 780         case SSH_AGENTC_UNLOCK:
 781                 process_lock_agent(e, type == SSH_AGENTC_LOCK);
 782                 break;
 783         /* ssh1 */
 784         case SSH_AGENTC_RSA_CHALLENGE:
 785                 process_authentication_challenge1(e);
 786                 break;
 787         case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
 788                 process_request_identities(e, 1);
 789                 break;
 790         case SSH_AGENTC_ADD_RSA_IDENTITY:
 791         case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED:
 792                 process_add_identity(e, 1);
 793                 break;
 794         case SSH_AGENTC_REMOVE_RSA_IDENTITY:
 795                 process_remove_identity(e, 1);
 796                 break;
 797         case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
 798                 process_remove_all_identities(e, 1);
 799                 break;
 800         /* ssh2 */
 801         case SSH2_AGENTC_SIGN_REQUEST:
 802                 process_sign_request2(e);
 803                 break;
 804         case SSH2_AGENTC_REQUEST_IDENTITIES:
 805                 process_request_identities(e, 2);
 806                 break;
 807         case SSH2_AGENTC_ADD_IDENTITY:
 808         case SSH2_AGENTC_ADD_ID_CONSTRAINED:
 809                 process_add_identity(e, 2);
 810                 break;
 811         case SSH2_AGENTC_REMOVE_IDENTITY:
 812                 process_remove_identity(e, 2);
 813                 break;
 814         case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
 815                 process_remove_all_identities(e, 2);
 816                 break;
 817 #ifdef ENABLE_PKCS11
 818         case SSH_AGENTC_ADD_SMARTCARD_KEY:
 819         case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED:
 820                 process_add_smartcard_key(e);
 821                 break;
 822         case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
 823                 process_remove_smartcard_key(e);
 824                 break;
 825 #endif /* ENABLE_PKCS11 */
 826         default:
 827                 /* Unknown message.  Respond with failure. */
 828                 error("Unknown message %d", type);
 829                 buffer_clear(&e->request);
 830                 buffer_put_int(&e->output, 1);
 831                 buffer_put_char(&e->output, SSH_AGENT_FAILURE);
 832                 break;
 833         }
 834 }
 835
 836 static void
 837 new_socket(sock_type type, int fd)
 838 {
 839         u_int i, old_alloc, new_alloc;
 840
 841         set_nonblock(fd);
 842
 843         if (fd > max_fd)
 844                 max_fd = fd;
 845
 846         for (i = 0; i < sockets_alloc; i++)
 847                 if (sockets[i].type == AUTH_UNUSED) {
 848                         sockets[i].fd = fd;
 849                         buffer_init(&sockets[i].input);
 850                         buffer_init(&sockets[i].output);
 851                         buffer_init(&sockets[i].request);
 852                         sockets[i].type = type;
 853                         return;
 854                 }
 855         old_alloc = sockets_alloc;
 856         new_alloc = sockets_alloc + 10;
 857         sockets = xrealloc(sockets, new_alloc, sizeof(sockets[0]));
 858         for (i = old_alloc; i < new_alloc; i++)
 859                 sockets[i].type = AUTH_UNUSED;
 860         sockets_alloc = new_alloc;
 861         sockets[old_alloc].fd = fd;
 862         buffer_init(&sockets[old_alloc].input);
 863         buffer_init(&sockets[old_alloc].output);
 864         buffer_init(&sockets[old_alloc].request);
 865         sockets[old_alloc].type = type;
 866 }
 867
 868 static int
 869 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp,
 870     struct timeval **tvpp)
 871 {
 872         u_int i, sz, deadline;
 873         int n = 0;
 874         static struct timeval tv;
 875
 876         for (i = 0; i < sockets_alloc; i++) {
 877                 switch (sockets[i].type) {
 878                 case AUTH_SOCKET:
 879                 case AUTH_CONNECTION:
 880                         n = MAX(n, sockets[i].fd);
 881                         break;
 882                 case AUTH_UNUSED:
 883                         break;
 884                 default:
 885                         fatal("Unknown socket type %d", sockets[i].type);
 886                         break;
 887                 }
 888         }
 889
 890         sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
 891         if (*fdrp == NULL || sz > *nallocp) {
 892                 if (*fdrp)
 893                         xfree(*fdrp);
 894                 if (*fdwp)
 895                         xfree(*fdwp);
 896                 *fdrp = xmalloc(sz);
 897                 *fdwp = xmalloc(sz);
 898                 *nallocp = sz;
 899         }
 900         if (n < *fdl)
 901                 debug("XXX shrink: %d < %d", n, *fdl);
 902         *fdl = n;
 903         memset(*fdrp, 0, sz);
 904         memset(*fdwp, 0, sz);
 905
 906         for (i = 0; i < sockets_alloc; i++) {
 907                 switch (sockets[i].type) {
 908                 case AUTH_SOCKET:
 909                 case AUTH_CONNECTION:
 910                         FD_SET(sockets[i].fd, *fdrp);
 911                         if (buffer_len(&sockets[i].output) > 0)
 912                                 FD_SET(sockets[i].fd, *fdwp);
 913                         break;
 914                 default:
 915                         break;
 916                 }
 917         }
 918         deadline = reaper();
 919         if (parent_alive_interval != 0)
 920                 deadline = (deadline == 0) ? parent_alive_interval :
 921                     MIN(deadline, parent_alive_interval);
 922         if (deadline == 0) {
 923                 *tvpp = NULL;
 924         } else {
 925                 tv.tv_sec = deadline;
 926                 tv.tv_usec = 0;
 927                 *tvpp = &tv;
 928         }
 929         return (1);
 930 }
 931
 932 static void
 933 after_select(fd_set *readset, fd_set *writeset)
 934 {
 935         struct sockaddr_un sunaddr;
 936         socklen_t slen;
 937         char buf[1024];
 938         int len, sock;
 939         u_int i, orig_alloc;
 940         uid_t euid;
 941         gid_t egid;
 942
 943         for (i = 0, orig_alloc = sockets_alloc; i < orig_alloc; i++)
 944                 switch (sockets[i].type) {
 945                 case AUTH_UNUSED:
 946                         break;
 947                 case AUTH_SOCKET:
 948                         if (FD_ISSET(sockets[i].fd, readset)) {
 949                                 slen = sizeof(sunaddr);
 950                                 sock = accept(sockets[i].fd,
 951                                     (struct sockaddr *)&sunaddr, &slen);
 952                                 if (sock < 0) {
 953                                         error("accept from AUTH_SOCKET: %s",
 954                                             strerror(errno));
 955                                         break;
 956                                 }
 957                                 if (getpeereid(sock, &euid, &egid) < 0) {
 958                                         error("getpeereid %d failed: %s",
 959                                             sock, strerror(errno));
 960                                         close(sock);
 961                                         break;
 962                                 }
 963                                 if ((euid != 0) && (getuid() != euid)) {
 964                                         error("uid mismatch: "
 965                                             "peer euid %u != uid %u",
 966                                             (u_int) euid, (u_int) getuid());
 967                                         close(sock);
 968                                         break;
 969                                 }
 970                                 new_socket(AUTH_CONNECTION, sock);
 971                         }
 972                         break;
 973                 case AUTH_CONNECTION:
 974                         if (buffer_len(&sockets[i].output) > 0 &&
 975                             FD_ISSET(sockets[i].fd, writeset)) {
 976                                 len = write(sockets[i].fd,
 977                                     buffer_ptr(&sockets[i].output),
 978                                     buffer_len(&sockets[i].output));
 979                                 if (len == -1 && (errno == EAGAIN ||
 980                                     errno == EWOULDBLOCK ||
 981                                     errno == EINTR))
 982                                         continue;
 983                                 if (len <= 0) {
 984                                         close_socket(&sockets[i]);
 985                                         break;
 986                                 }
 987                                 buffer_consume(&sockets[i].output, len);
 988                         }
 989                         if (FD_ISSET(sockets[i].fd, readset)) {
 990                                 len = read(sockets[i].fd, buf, sizeof(buf));
 991                                 if (len == -1 && (errno == EAGAIN ||
 992                                     errno == EWOULDBLOCK ||
 993                                     errno == EINTR))
 994                                         continue;
 995                                 if (len <= 0) {
 996                                         close_socket(&sockets[i]);
 997                                         break;
 998                                 }
 999                                 buffer_append(&sockets[i].input, buf, len);
1000                                 process_message(&sockets[i]);
1001                         }
1002                         break;
1003                 default:
1004                         fatal("Unknown type %d", sockets[i].type);
1005                 }
1006 }
1007
1008 static void
1009 cleanup_socket(void)
1010 {
1011         if (socket_name[0])
1012                 unlink(socket_name);
1013         if (socket_dir[0])
1014                 rmdir(socket_dir);
1015 }
1016
1017 void
1018 cleanup_exit(int i)
1019 {
1020         cleanup_socket();
1021         _exit(i);
1022 }
1023
1024 /*ARGSUSED*/
1025 static void
1026 cleanup_handler(int sig)
1027 {
1028         cleanup_socket();
1029 #ifdef ENABLE_PKCS11
1030         pkcs11_terminate();
1031 #endif
1032         _exit(2);
1033 }
1034
1035 static void
1036 check_parent_exists(void)
1037 {
1038         if (parent_pid != -1 && kill(parent_pid, 0) < 0) {
1039                 /* printf("Parent has died - Authentication agent exiting.\n"); */
1040                 cleanup_socket();
1041                 _exit(2);
1042         }
1043 }
1044
1045 static void
1046 usage(void)
1047 {
1048         fprintf(stderr, "usage: %s [options] [command [arg ...]]\n",
1049             __progname);
1050         fprintf(stderr, "Options:\n");
1051         fprintf(stderr, "  -c          Generate C-shell commands on stdout.\n");
1052         fprintf(stderr, "  -s          Generate Bourne shell commands on stdout.\n");
1053         fprintf(stderr, "  -k          Kill the current agent.\n");
1054         fprintf(stderr, "  -d          Debug mode.\n");
1055         fprintf(stderr, "  -a socket   Bind agent socket to given name.\n");
1056         fprintf(stderr, "  -t life     Default identity lifetime (seconds).\n");
1057         exit(1);
1058 }
1059
1060 int
1061 main(int ac, char **av)
1062 {
1063         int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0;
1064         int sock, fd, ch, result, saved_errno;
1065         u_int nalloc;
1066         char *shell, *format, *pidstr, *agentsocket = NULL;
1067         fd_set *readsetp = NULL, *writesetp = NULL;
1068         struct sockaddr_un sunaddr;
1069 #ifdef HAVE_SETRLIMIT
1070         struct rlimit rlim;
1071 #endif
1072         int prev_mask;
1073         extern int optind;
1074         extern char *optarg;
1075         pid_t pid;
1076         char pidstrbuf[1 + 3 * sizeof pid];
1077         struct timeval *tvp = NULL;
1078         size_t len;
1079
1080         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1081         sanitise_stdfd();
1082
1083         /* drop */
1084         setegid(getgid());
1085         setgid(getgid());
1086
1087 #if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE)
1088         /* Disable ptrace on Linux without sgid bit */
1089         prctl(PR_SET_DUMPABLE, 0);
1090 #endif
1091
1092         SSLeay_add_all_algorithms();
1093
1094         __progname = ssh_get_progname(av[0]);
1095         init_rng();
1096         seed_rng();
1097
1098         while ((ch = getopt(ac, av, "cdksa:t:")) != -1) {
1099                 switch (ch) {
1100                 case 'c':
1101                         if (s_flag)
1102                                 usage();
1103                         c_flag++;
1104                         break;
1105                 case 'k':
1106                         k_flag++;
1107                         break;
1108                 case 's':
1109                         if (c_flag)
1110                                 usage();
1111                         s_flag++;
1112                         break;
1113                 case 'd':
1114                         if (d_flag)
1115                                 usage();
1116                         d_flag++;
1117                         break;
1118                 case 'a':
1119                         agentsocket = optarg;
1120                         break;
1121                 case 't':
1122                         if ((lifetime = convtime(optarg)) == -1) {
1123                                 fprintf(stderr, "Invalid lifetime\n");
1124                                 usage();
1125                         }
1126                         break;
1127                 default:
1128                         usage();
1129                 }
1130         }
1131         ac -= optind;
1132         av += optind;
1133
1134         if (ac > 0 && (c_flag || k_flag || s_flag || d_flag))
1135                 usage();
1136
1137         if (ac == 0 && !c_flag && !s_flag) {
1138                 shell = getenv("SHELL");
1139                 if (shell != NULL && (len = strlen(shell)) > 2 &&
1140                     strncmp(shell + len - 3, "csh", 3) == 0)
1141                         c_flag = 1;
1142         }
1143         if (k_flag) {
1144                 const char *errstr = NULL;
1145
1146                 pidstr = getenv(SSH_AGENTPID_ENV_NAME);
1147                 if (pidstr == NULL) {
1148                         fprintf(stderr, "%s not set, cannot kill agent\n",
1149                             SSH_AGENTPID_ENV_NAME);
1150                         exit(1);
1151                 }
1152                 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr);
1153                 if (errstr) {
1154                         fprintf(stderr,
1155                             "%s=\"%s\", which is not a good PID: %s\n",
1156                             SSH_AGENTPID_ENV_NAME, pidstr, errstr);
1157                         exit(1);
1158                 }
1159                 if (kill(pid, SIGTERM) == -1) {
1160                         perror("kill");
1161                         exit(1);
1162                 }
1163                 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
1164                 printf(format, SSH_AUTHSOCKET_ENV_NAME);
1165                 printf(format, SSH_AGENTPID_ENV_NAME);
1166                 printf("echo Agent pid %ld killed;\n", (long)pid);
1167                 exit(0);
1168         }
1169         parent_pid = getpid();
1170
1171         if (agentsocket == NULL) {
1172                 /* Create private directory for agent socket */
1173                 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXXXX", sizeof socket_dir);
1174                 if (mkdtemp(socket_dir) == NULL) {
1175                         perror("mkdtemp: private socket dir");
1176                         exit(1);
1177                 }
1178                 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir,
1179                     (long)parent_pid);
1180         } else {
1181                 /* Try to use specified agent socket */
1182                 socket_dir[0] = '\0';
1183                 strlcpy(socket_name, agentsocket, sizeof socket_name);
1184         }
1185
1186         /*
1187          * Create socket early so it will exist before command gets run from
1188          * the parent.
1189          */
1190         sock = socket(AF_UNIX, SOCK_STREAM, 0);
1191         if (sock < 0) {
1192                 perror("socket");
1193                 *socket_name = '\0'; /* Don't unlink any existing file */
1194                 cleanup_exit(1);
1195         }
1196         memset(&sunaddr, 0, sizeof(sunaddr));
1197         sunaddr.sun_family = AF_UNIX;
1198         strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path));
1199         prev_mask = umask(0177);
1200         if (bind(sock, (struct sockaddr *) &sunaddr, sizeof(sunaddr)) < 0) {
1201                 perror("bind");
1202                 *socket_name = '\0'; /* Don't unlink any existing file */
1203                 umask(prev_mask);
1204                 cleanup_exit(1);
1205         }
1206         umask(prev_mask);
1207         if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
1208                 perror("listen");
1209                 cleanup_exit(1);
1210         }
1211
1212         /*
1213          * Fork, and have the parent execute the command, if any, or present
1214          * the socket data.  The child continues as the authentication agent.
1215          */
1216         if (d_flag) {
1217                 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1);
1218                 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1219                 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1220                     SSH_AUTHSOCKET_ENV_NAME);
1221                 printf("echo Agent pid %ld;\n", (long)parent_pid);
1222                 goto skip;
1223         }
1224         pid = fork();
1225         if (pid == -1) {
1226                 perror("fork");
1227                 cleanup_exit(1);
1228         }
1229         if (pid != 0) {         /* Parent - execute the given command. */
1230                 close(sock);
1231                 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid);
1232                 if (ac == 0) {
1233                         format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1234                         printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1235                             SSH_AUTHSOCKET_ENV_NAME);
1236                         printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
1237                             SSH_AGENTPID_ENV_NAME);
1238                         printf("echo Agent pid %ld;\n", (long)pid);
1239                         exit(0);
1240                 }
1241                 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 ||
1242                     setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) {
1243                         perror("setenv");
1244                         exit(1);
1245                 }
1246                 execvp(av[0], av);
1247                 perror(av[0]);
1248                 exit(1);
1249         }
1250         /* child */
1251         log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0);
1252
1253         if (setsid() == -1) {
1254                 error("setsid: %s", strerror(errno));
1255                 cleanup_exit(1);
1256         }
1257
1258         (void)chdir("/");
1259         if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1260                 /* XXX might close listen socket */
1261                 (void)dup2(fd, STDIN_FILENO);
1262                 (void)dup2(fd, STDOUT_FILENO);
1263                 (void)dup2(fd, STDERR_FILENO);
1264                 if (fd > 2)
1265                         close(fd);
1266         }
1267
1268 #ifdef HAVE_SETRLIMIT
1269         /* deny core dumps, since memory contains unencrypted private keys */
1270         rlim.rlim_cur = rlim.rlim_max = 0;
1271         if (setrlimit(RLIMIT_CORE, &rlim) < 0) {
1272                 error("setrlimit RLIMIT_CORE: %s", strerror(errno));
1273                 cleanup_exit(1);
1274         }
1275 #endif
1276
1277 skip:
1278
1279 #ifdef ENABLE_PKCS11
1280         pkcs11_init(0);
1281 #endif
1282         new_socket(AUTH_SOCKET, sock);
1283         if (ac > 0)
1284                 parent_alive_interval = 10;
1285         idtab_init();
1286         if (!d_flag)
1287                 signal(SIGINT, SIG_IGN);
1288         signal(SIGPIPE, SIG_IGN);
1289         signal(SIGHUP, cleanup_handler);
1290         signal(SIGTERM, cleanup_handler);
1291         nalloc = 0;
1292
1293         while (1) {
1294                 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp);
1295                 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp);
1296                 saved_errno = errno;
1297                 if (parent_alive_interval != 0)
1298                         check_parent_exists();
1299                 (void) reaper();        /* remove expired keys */
1300                 if (result < 0) {
1301                         if (saved_errno == EINTR)
1302                                 continue;
1303                         fatal("select: %s", strerror(saved_errno));
1304                 } else if (result > 0)
1305                         after_select(readsetp, writesetp);
1306         }
1307         /* NOTREACHED */
1308 }