crypto/openssh/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 __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:
 505                         cert = buffer_get_string(&e->request, &len);
 506                         if ((k = key_from_blob(cert, len)) == NULL)
 507                                 fatal("Certificate parse failed");
 508                         xfree(cert);
 509                         key_add_private(k);
 510                         buffer_get_bignum2(&e->request, k->dsa->priv_key);
 511                         break;
 512                 case KEY_RSA:
 513                         k = key_new_private(type);
 514                         buffer_get_bignum2(&e->request, k->rsa->n);
 515                         buffer_get_bignum2(&e->request, k->rsa->e);
 516                         buffer_get_bignum2(&e->request, k->rsa->d);
 517                         buffer_get_bignum2(&e->request, k->rsa->iqmp);
 518                         buffer_get_bignum2(&e->request, k->rsa->p);
 519                         buffer_get_bignum2(&e->request, k->rsa->q);
 520
 521                         /* Generate additional parameters */
 522                         rsa_generate_additional_parameters(k->rsa);
 523                         break;
 524                 case KEY_RSA_CERT:
 525                         cert = buffer_get_string(&e->request, &len);
 526                         if ((k = key_from_blob(cert, len)) == NULL)
 527                                 fatal("Certificate parse failed");
 528                         xfree(cert);
 529                         key_add_private(k);
 530                         buffer_get_bignum2(&e->request, k->rsa->d);
 531                         buffer_get_bignum2(&e->request, k->rsa->iqmp);
 532                         buffer_get_bignum2(&e->request, k->rsa->p);
 533                         buffer_get_bignum2(&e->request, k->rsa->q);
 534                         break;
 535                 default:
 536                         buffer_clear(&e->request);
 537                         goto send;
 538                 }
 539                 break;
 540         }
 541         /* enable blinding */
 542         switch (k->type) {
 543         case KEY_RSA:
 544         case KEY_RSA_CERT:
 545         case KEY_RSA1:
 546                 if (RSA_blinding_on(k->rsa, NULL) != 1) {
 547                         error("process_add_identity: RSA_blinding_on failed");
 548                         key_free(k);
 549                         goto send;
 550                 }
 551                 break;
 552         }
 553         comment = buffer_get_string(&e->request, NULL);
 554         if (k == NULL) {
 555                 xfree(comment);
 556                 goto send;
 557         }
 558         while (buffer_len(&e->request)) {
 559                 switch ((type = buffer_get_char(&e->request))) {
 560                 case SSH_AGENT_CONSTRAIN_LIFETIME:
 561                         death = time(NULL) + buffer_get_int(&e->request);
 562                         break;
 563                 case SSH_AGENT_CONSTRAIN_CONFIRM:
 564                         confirm = 1;
 565                         break;
 566                 default:
 567                         error("process_add_identity: "
 568                             "Unknown constraint type %d", type);
 569                         xfree(comment);
 570                         key_free(k);
 571                         goto send;
 572                 }
 573         }
 574         success = 1;
 575         if (lifetime && !death)
 576                 death = time(NULL) + lifetime;
 577         if ((id = lookup_identity(k, version)) == NULL) {
 578                 id = xcalloc(1, sizeof(Identity));
 579                 id->key = k;
 580                 TAILQ_INSERT_TAIL(&tab->idlist, id, next);
 581                 /* Increment the number of identities. */
 582                 tab->nentries++;
 583         } else {
 584                 key_free(k);
 585                 xfree(id->comment);
 586         }
 587         id->comment = comment;
 588         id->death = death;
 589         id->confirm = confirm;
 590 send:
 591         buffer_put_int(&e->output, 1);
 592         buffer_put_char(&e->output,
 593             success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
 594 }
 595
 596 /* XXX todo: encrypt sensitive data with passphrase */
 597 static void
 598 process_lock_agent(SocketEntry *e, int lock)
 599 {
 600         int success = 0;
 601         char *passwd;
 602
 603         passwd = buffer_get_string(&e->request, NULL);
 604         if (locked && !lock && strcmp(passwd, lock_passwd) == 0) {
 605                 locked = 0;
 606                 memset(lock_passwd, 0, strlen(lock_passwd));
 607                 xfree(lock_passwd);
 608                 lock_passwd = NULL;
 609                 success = 1;
 610         } else if (!locked && lock) {
 611                 locked = 1;
 612                 lock_passwd = xstrdup(passwd);
 613                 success = 1;
 614         }
 615         memset(passwd, 0, strlen(passwd));
 616         xfree(passwd);
 617
 618         buffer_put_int(&e->output, 1);
 619         buffer_put_char(&e->output,
 620             success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
 621 }
 622
 623 static void
 624 no_identities(SocketEntry *e, u_int type)
 625 {
 626         Buffer msg;
 627
 628         buffer_init(&msg);
 629         buffer_put_char(&msg,
 630             (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ?
 631             SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
 632         buffer_put_int(&msg, 0);
 633         buffer_put_int(&e->output, buffer_len(&msg));
 634         buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
 635         buffer_free(&msg);
 636 }
 637
 638 #ifdef ENABLE_PKCS11
 639 static void
 640 process_add_smartcard_key(SocketEntry *e)
 641 {
 642         char *provider = NULL, *pin;
 643         int i, type, version, count = 0, success = 0, death = 0, confirm = 0;
 644         Key **keys = NULL, *k;
 645         Identity *id;
 646         Idtab *tab;
 647
 648         provider = buffer_get_string(&e->request, NULL);
 649         pin = buffer_get_string(&e->request, NULL);
 650
 651         while (buffer_len(&e->request)) {
 652                 switch ((type = buffer_get_char(&e->request))) {
 653                 case SSH_AGENT_CONSTRAIN_LIFETIME:
 654                         death = time(NULL) + buffer_get_int(&e->request);
 655                         break;
 656                 case SSH_AGENT_CONSTRAIN_CONFIRM:
 657                         confirm = 1;
 658                         break;
 659                 default:
 660                         error("process_add_smartcard_key: "
 661                             "Unknown constraint type %d", type);
 662                         goto send;
 663                 }
 664         }
 665         if (lifetime && !death)
 666                 death = time(NULL) + lifetime;
 667
 668         count = pkcs11_add_provider(provider, pin, &keys);
 669         for (i = 0; i < count; i++) {
 670                 k = keys[i];
 671                 version = k->type == KEY_RSA1 ? 1 : 2;
 672                 tab = idtab_lookup(version);
 673                 if (lookup_identity(k, version) == NULL) {
 674                         id = xcalloc(1, sizeof(Identity));
 675                         id->key = k;
 676                         id->provider = xstrdup(provider);
 677                         id->comment = xstrdup(provider); /* XXX */
 678                         id->death = death;
 679                         id->confirm = confirm;
 680                         TAILQ_INSERT_TAIL(&tab->idlist, id, next);
 681                         tab->nentries++;
 682                         success = 1;
 683                 } else {
 684                         key_free(k);
 685                 }
 686                 keys[i] = NULL;
 687         }
 688 send:
 689         if (pin)
 690                 xfree(pin);
 691         if (provider)
 692                 xfree(provider);
 693         if (keys)
 694                 xfree(keys);
 695         buffer_put_int(&e->output, 1);
 696         buffer_put_char(&e->output,
 697             success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
 698 }
 699
 700 static void
 701 process_remove_smartcard_key(SocketEntry *e)
 702 {
 703         char *provider = NULL, *pin = NULL;
 704         int version, success = 0;
 705         Identity *id, *nxt;
 706         Idtab *tab;
 707
 708         provider = buffer_get_string(&e->request, NULL);
 709         pin = buffer_get_string(&e->request, NULL);
 710         xfree(pin);
 711
 712         for (version = 1; version < 3; version++) {
 713                 tab = idtab_lookup(version);
 714                 for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) {
 715                         nxt = TAILQ_NEXT(id, next);
 716                         if (!strcmp(provider, id->provider)) {
 717                                 TAILQ_REMOVE(&tab->idlist, id, next);
 718                                 free_identity(id);
 719                                 tab->nentries--;
 720                         }
 721                 }
 722         }
 723         if (pkcs11_del_provider(provider) == 0)
 724                 success = 1;
 725         else
 726                 error("process_remove_smartcard_key:"
 727                     " pkcs11_del_provider failed");
 728         xfree(provider);
 729         buffer_put_int(&e->output, 1);
 730         buffer_put_char(&e->output,
 731             success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
 732 }
 733 #endif /* ENABLE_PKCS11 */
 734
 735 /* dispatch incoming messages */
 736
 737 static void
 738 process_message(SocketEntry *e)
 739 {
 740         u_int msg_len, type;
 741         u_char *cp;
 742
 743         if (buffer_len(&e->input) < 5)
 744                 return;         /* Incomplete message. */
 745         cp = buffer_ptr(&e->input);
 746         msg_len = get_u32(cp);
 747         if (msg_len > 256 * 1024) {
 748                 close_socket(e);
 749                 return;
 750         }
 751         if (buffer_len(&e->input) < msg_len + 4)
 752                 return;
 753
 754         /* move the current input to e->request */
 755         buffer_consume(&e->input, 4);
 756         buffer_clear(&e->request);
 757         buffer_append(&e->request, buffer_ptr(&e->input), msg_len);
 758         buffer_consume(&e->input, msg_len);
 759         type = buffer_get_char(&e->request);
 760
 761         /* check wheter agent is locked */
 762         if (locked && type != SSH_AGENTC_UNLOCK) {
 763                 buffer_clear(&e->request);
 764                 switch (type) {
 765                 case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
 766                 case SSH2_AGENTC_REQUEST_IDENTITIES:
 767                         /* send empty lists */
 768                         no_identities(e, type);
 769                         break;
 770                 default:
 771                         /* send a fail message for all other request types */
 772                         buffer_put_int(&e->output, 1);
 773                         buffer_put_char(&e->output, SSH_AGENT_FAILURE);
 774                 }
 775                 return;
 776         }
 777
 778         debug("type %d", type);
 779         switch (type) {
 780         case SSH_AGENTC_LOCK:
 781         case SSH_AGENTC_UNLOCK:
 782                 process_lock_agent(e, type == SSH_AGENTC_LOCK);
 783                 break;
 784         /* ssh1 */
 785         case SSH_AGENTC_RSA_CHALLENGE:
 786                 process_authentication_challenge1(e);
 787                 break;
 788         case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
 789                 process_request_identities(e, 1);
 790                 break;
 791         case SSH_AGENTC_ADD_RSA_IDENTITY:
 792         case SSH_AGENTC_ADD_RSA_ID_CONSTRAINED:
 793                 process_add_identity(e, 1);
 794                 break;
 795         case SSH_AGENTC_REMOVE_RSA_IDENTITY:
 796                 process_remove_identity(e, 1);
 797                 break;
 798         case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
 799                 process_remove_all_identities(e, 1);
 800                 break;
 801         /* ssh2 */
 802         case SSH2_AGENTC_SIGN_REQUEST:
 803                 process_sign_request2(e);
 804                 break;
 805         case SSH2_AGENTC_REQUEST_IDENTITIES:
 806                 process_request_identities(e, 2);
 807                 break;
 808         case SSH2_AGENTC_ADD_IDENTITY:
 809         case SSH2_AGENTC_ADD_ID_CONSTRAINED:
 810                 process_add_identity(e, 2);
 811                 break;
 812         case SSH2_AGENTC_REMOVE_IDENTITY:
 813                 process_remove_identity(e, 2);
 814                 break;
 815         case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
 816                 process_remove_all_identities(e, 2);
 817                 break;
 818 #ifdef ENABLE_PKCS11
 819         case SSH_AGENTC_ADD_SMARTCARD_KEY:
 820         case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED:
 821                 process_add_smartcard_key(e);
 822                 break;
 823         case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
 824                 process_remove_smartcard_key(e);
 825                 break;
 826 #endif /* ENABLE_PKCS11 */
 827         default:
 828                 /* Unknown message.  Respond with failure. */
 829                 error("Unknown message %d", type);
 830                 buffer_clear(&e->request);
 831                 buffer_put_int(&e->output, 1);
 832                 buffer_put_char(&e->output, SSH_AGENT_FAILURE);
 833                 break;
 834         }
 835 }
 836
 837 static void
 838 new_socket(sock_type type, int fd)
 839 {
 840         u_int i, old_alloc, new_alloc;
 841
 842         set_nonblock(fd);
 843
 844         if (fd > max_fd)
 845                 max_fd = fd;
 846
 847         for (i = 0; i < sockets_alloc; i++)
 848                 if (sockets[i].type == AUTH_UNUSED) {
 849                         sockets[i].fd = fd;
 850                         buffer_init(&sockets[i].input);
 851                         buffer_init(&sockets[i].output);
 852                         buffer_init(&sockets[i].request);
 853                         sockets[i].type = type;
 854                         return;
 855                 }
 856         old_alloc = sockets_alloc;
 857         new_alloc = sockets_alloc + 10;
 858         sockets = xrealloc(sockets, new_alloc, sizeof(sockets[0]));
 859         for (i = old_alloc; i < new_alloc; i++)
 860                 sockets[i].type = AUTH_UNUSED;
 861         sockets_alloc = new_alloc;
 862         sockets[old_alloc].fd = fd;
 863         buffer_init(&sockets[old_alloc].input);
 864         buffer_init(&sockets[old_alloc].output);
 865         buffer_init(&sockets[old_alloc].request);
 866         sockets[old_alloc].type = type;
 867 }
 868
 869 static int
 870 prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp,
 871     struct timeval **tvpp)
 872 {
 873         u_int i, sz, deadline;
 874         int n = 0;
 875         static struct timeval tv;
 876
 877         for (i = 0; i < sockets_alloc; i++) {
 878                 switch (sockets[i].type) {
 879                 case AUTH_SOCKET:
 880                 case AUTH_CONNECTION:
 881                         n = MAX(n, sockets[i].fd);
 882                         break;
 883                 case AUTH_UNUSED:
 884                         break;
 885                 default:
 886                         fatal("Unknown socket type %d", sockets[i].type);
 887                         break;
 888                 }
 889         }
 890
 891         sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
 892         if (*fdrp == NULL || sz > *nallocp) {
 893                 if (*fdrp)
 894                         xfree(*fdrp);
 895                 if (*fdwp)
 896                         xfree(*fdwp);
 897                 *fdrp = xmalloc(sz);
 898                 *fdwp = xmalloc(sz);
 899                 *nallocp = sz;
 900         }
 901         if (n < *fdl)
 902                 debug("XXX shrink: %d < %d", n, *fdl);
 903         *fdl = n;
 904         memset(*fdrp, 0, sz);
 905         memset(*fdwp, 0, sz);
 906
 907         for (i = 0; i < sockets_alloc; i++) {
 908                 switch (sockets[i].type) {
 909                 case AUTH_SOCKET:
 910                 case AUTH_CONNECTION:
 911                         FD_SET(sockets[i].fd, *fdrp);
 912                         if (buffer_len(&sockets[i].output) > 0)
 913                                 FD_SET(sockets[i].fd, *fdwp);
 914                         break;
 915                 default:
 916                         break;
 917                 }
 918         }
 919         deadline = reaper();
 920         if (parent_alive_interval != 0)
 921                 deadline = (deadline == 0) ? parent_alive_interval :
 922                     MIN(deadline, parent_alive_interval);
 923         if (deadline == 0) {
 924                 *tvpp = NULL;
 925         } else {
 926                 tv.tv_sec = deadline;
 927                 tv.tv_usec = 0;
 928                 *tvpp = &tv;
 929         }
 930         return (1);
 931 }
 932
 933 static void
 934 after_select(fd_set *readset, fd_set *writeset)
 935 {
 936         struct sockaddr_un sunaddr;
 937         socklen_t slen;
 938         char buf[1024];
 939         int len, sock;
 940         u_int i, orig_alloc;
 941         uid_t euid;
 942         gid_t egid;
 943
 944         for (i = 0, orig_alloc = sockets_alloc; i < orig_alloc; i++)
 945                 switch (sockets[i].type) {
 946                 case AUTH_UNUSED:
 947                         break;
 948                 case AUTH_SOCKET:
 949                         if (FD_ISSET(sockets[i].fd, readset)) {
 950                                 slen = sizeof(sunaddr);
 951                                 sock = accept(sockets[i].fd,
 952                                     (struct sockaddr *)&sunaddr, &slen);
 953                                 if (sock < 0) {
 954                                         error("accept from AUTH_SOCKET: %s",
 955                                             strerror(errno));
 956                                         break;
 957                                 }
 958                                 if (getpeereid(sock, &euid, &egid) < 0) {
 959                                         error("getpeereid %d failed: %s",
 960                                             sock, strerror(errno));
 961                                         close(sock);
 962                                         break;
 963                                 }
 964                                 if ((euid != 0) && (getuid() != euid)) {
 965                                         error("uid mismatch: "
 966                                             "peer euid %u != uid %u",
 967                                             (u_int) euid, (u_int) getuid());
 968                                         close(sock);
 969                                         break;
 970                                 }
 971                                 new_socket(AUTH_CONNECTION, sock);
 972                         }
 973                         break;
 974                 case AUTH_CONNECTION:
 975                         if (buffer_len(&sockets[i].output) > 0 &&
 976                             FD_ISSET(sockets[i].fd, writeset)) {
 977                                 len = write(sockets[i].fd,
 978                                     buffer_ptr(&sockets[i].output),
 979                                     buffer_len(&sockets[i].output));
 980                                 if (len == -1 && (errno == EAGAIN ||
 981                                     errno == EWOULDBLOCK ||
 982                                     errno == EINTR))
 983                                         continue;
 984                                 if (len <= 0) {
 985                                         close_socket(&sockets[i]);
 986                                         break;
 987                                 }
 988                                 buffer_consume(&sockets[i].output, len);
 989                         }
 990                         if (FD_ISSET(sockets[i].fd, readset)) {
 991                                 len = read(sockets[i].fd, buf, sizeof(buf));
 992                                 if (len == -1 && (errno == EAGAIN ||
 993                                     errno == EWOULDBLOCK ||
 994                                     errno == EINTR))
 995                                         continue;
 996                                 if (len <= 0) {
 997                                         close_socket(&sockets[i]);
 998                                         break;
 999                                 }
1000                                 buffer_append(&sockets[i].input, buf, len);
1001                                 process_message(&sockets[i]);
1002                         }
1003                         break;
1004                 default:
1005                         fatal("Unknown type %d", sockets[i].type);
1006                 }
1007 }
1008
1009 static void
1010 cleanup_socket(void)
1011 {
1012         if (socket_name[0])
1013                 unlink(socket_name);
1014         if (socket_dir[0])
1015                 rmdir(socket_dir);
1016 }
1017
1018 void
1019 cleanup_exit(int i)
1020 {
1021         cleanup_socket();
1022         _exit(i);
1023 }
1024
1025 /*ARGSUSED*/
1026 static void
1027 cleanup_handler(int sig)
1028 {
1029         cleanup_socket();
1030 #ifdef ENABLE_PKCS11
1031         pkcs11_terminate();
1032 #endif
1033         _exit(2);
1034 }
1035
1036 static void
1037 check_parent_exists(void)
1038 {
1039         if (parent_pid != -1 && kill(parent_pid, 0) < 0) {
1040                 /* printf("Parent has died - Authentication agent exiting.\n"); */
1041                 cleanup_socket();
1042                 _exit(2);
1043         }
1044 }
1045
1046 static void
1047 usage(void)
1048 {
1049         fprintf(stderr, "usage: %s [options] [command [arg ...]]\n",
1050             __progname);
1051         fprintf(stderr, "Options:\n");
1052         fprintf(stderr, "  -c          Generate C-shell commands on stdout.\n");
1053         fprintf(stderr, "  -s          Generate Bourne shell commands on stdout.\n");
1054         fprintf(stderr, "  -k          Kill the current agent.\n");
1055         fprintf(stderr, "  -d          Debug mode.\n");
1056         fprintf(stderr, "  -a socket   Bind agent socket to given name.\n");
1057         fprintf(stderr, "  -t life     Default identity lifetime (seconds).\n");
1058         exit(1);
1059 }
1060
1061 int
1062 main(int ac, char **av)
1063 {
1064         int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0;
1065         int sock, fd, ch, result, saved_errno;
1066         u_int nalloc;
1067         char *shell, *format, *pidstr, *agentsocket = NULL;
1068         fd_set *readsetp = NULL, *writesetp = NULL;
1069         struct sockaddr_un sunaddr;
1070 #ifdef HAVE_SETRLIMIT
1071         struct rlimit rlim;
1072 #endif
1073         int prev_mask;
1074         extern int optind;
1075         extern char *optarg;
1076         pid_t pid;
1077         char pidstrbuf[1 + 3 * sizeof pid];
1078         struct timeval *tvp = NULL;
1079         size_t len;
1080
1081         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1082         sanitise_stdfd();
1083
1084         /* drop */
1085         setegid(getgid());
1086         setgid(getgid());
1087         setuid(geteuid());
1088
1089 #if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE)
1090         /* Disable ptrace on Linux without sgid bit */
1091         prctl(PR_SET_DUMPABLE, 0);
1092 #endif
1093
1094         SSLeay_add_all_algorithms();
1095
1096         __progname = ssh_get_progname(av[0]);
1097         init_rng();
1098         seed_rng();
1099
1100         while ((ch = getopt(ac, av, "cdksa:t:")) != -1) {
1101                 switch (ch) {
1102                 case 'c':
1103                         if (s_flag)
1104                                 usage();
1105                         c_flag++;
1106                         break;
1107                 case 'k':
1108                         k_flag++;
1109                         break;
1110                 case 's':
1111                         if (c_flag)
1112                                 usage();
1113                         s_flag++;
1114                         break;
1115                 case 'd':
1116                         if (d_flag)
1117                                 usage();
1118                         d_flag++;
1119                         break;
1120                 case 'a':
1121                         agentsocket = optarg;
1122                         break;
1123                 case 't':
1124                         if ((lifetime = convtime(optarg)) == -1) {
1125                                 fprintf(stderr, "Invalid lifetime\n");
1126                                 usage();
1127                         }
1128                         break;
1129                 default:
1130                         usage();
1131                 }
1132         }
1133         ac -= optind;
1134         av += optind;
1135
1136         if (ac > 0 && (c_flag || k_flag || s_flag || d_flag))
1137                 usage();
1138
1139         if (ac == 0 && !c_flag && !s_flag) {
1140                 shell = getenv("SHELL");
1141                 if (shell != NULL && (len = strlen(shell)) > 2 &&
1142                     strncmp(shell + len - 3, "csh", 3) == 0)
1143                         c_flag = 1;
1144         }
1145         if (k_flag) {
1146                 const char *errstr = NULL;
1147
1148                 pidstr = getenv(SSH_AGENTPID_ENV_NAME);
1149                 if (pidstr == NULL) {
1150                         fprintf(stderr, "%s not set, cannot kill agent\n",
1151                             SSH_AGENTPID_ENV_NAME);
1152                         exit(1);
1153                 }
1154                 pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr);
1155                 if (errstr) {
1156                         fprintf(stderr,
1157                             "%s=\"%s\", which is not a good PID: %s\n",
1158                             SSH_AGENTPID_ENV_NAME, pidstr, errstr);
1159                         exit(1);
1160                 }
1161                 if (kill(pid, SIGTERM) == -1) {
1162                         perror("kill");
1163                         exit(1);
1164                 }
1165                 format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
1166                 printf(format, SSH_AUTHSOCKET_ENV_NAME);
1167                 printf(format, SSH_AGENTPID_ENV_NAME);
1168                 printf("echo Agent pid %ld killed;\n", (long)pid);
1169                 exit(0);
1170         }
1171         parent_pid = getpid();
1172
1173         if (agentsocket == NULL) {
1174                 /* Create private directory for agent socket */
1175                 strlcpy(socket_dir, "/tmp/ssh-XXXXXXXXXX", sizeof socket_dir);
1176                 if (mkdtemp(socket_dir) == NULL) {
1177                         perror("mkdtemp: private socket dir");
1178                         exit(1);
1179                 }
1180                 snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir,
1181                     (long)parent_pid);
1182         } else {
1183                 /* Try to use specified agent socket */
1184                 socket_dir[0] = '\0';
1185                 strlcpy(socket_name, agentsocket, sizeof socket_name);
1186         }
1187
1188         /*
1189          * Create socket early so it will exist before command gets run from
1190          * the parent.
1191          */
1192         sock = socket(AF_UNIX, SOCK_STREAM, 0);
1193         if (sock < 0) {
1194                 perror("socket");
1195                 *socket_name = '\0'; /* Don't unlink any existing file */
1196                 cleanup_exit(1);
1197         }
1198         memset(&sunaddr, 0, sizeof(sunaddr));
1199         sunaddr.sun_family = AF_UNIX;
1200         strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path));
1201         prev_mask = umask(0177);
1202         if (bind(sock, (struct sockaddr *) &sunaddr, sizeof(sunaddr)) < 0) {
1203                 perror("bind");
1204                 *socket_name = '\0'; /* Don't unlink any existing file */
1205                 umask(prev_mask);
1206                 cleanup_exit(1);
1207         }
1208         umask(prev_mask);
1209         if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
1210                 perror("listen");
1211                 cleanup_exit(1);
1212         }
1213
1214         /*
1215          * Fork, and have the parent execute the command, if any, or present
1216          * the socket data.  The child continues as the authentication agent.
1217          */
1218         if (d_flag) {
1219                 log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1);
1220                 format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1221                 printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1222                     SSH_AUTHSOCKET_ENV_NAME);
1223                 printf("echo Agent pid %ld;\n", (long)parent_pid);
1224                 goto skip;
1225         }
1226         pid = fork();
1227         if (pid == -1) {
1228                 perror("fork");
1229                 cleanup_exit(1);
1230         }
1231         if (pid != 0) {         /* Parent - execute the given command. */
1232                 close(sock);
1233                 snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid);
1234                 if (ac == 0) {
1235                         format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
1236                         printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
1237                             SSH_AUTHSOCKET_ENV_NAME);
1238                         printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
1239                             SSH_AGENTPID_ENV_NAME);
1240                         printf("echo Agent pid %ld;\n", (long)pid);
1241                         exit(0);
1242                 }
1243                 if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 ||
1244                     setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) {
1245                         perror("setenv");
1246                         exit(1);
1247                 }
1248                 execvp(av[0], av);
1249                 perror(av[0]);
1250                 exit(1);
1251         }
1252         /* child */
1253         log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0);
1254
1255         if (setsid() == -1) {
1256                 error("setsid: %s", strerror(errno));
1257                 cleanup_exit(1);
1258         }
1259
1260         (void)chdir("/");
1261         if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1262                 /* XXX might close listen socket */
1263                 (void)dup2(fd, STDIN_FILENO);
1264                 (void)dup2(fd, STDOUT_FILENO);
1265                 (void)dup2(fd, STDERR_FILENO);
1266                 if (fd > 2)
1267                         close(fd);
1268         }
1269
1270 #ifdef HAVE_SETRLIMIT
1271         /* deny core dumps, since memory contains unencrypted private keys */
1272         rlim.rlim_cur = rlim.rlim_max = 0;
1273         if (setrlimit(RLIMIT_CORE, &rlim) < 0) {
1274                 error("setrlimit RLIMIT_CORE: %s", strerror(errno));
1275                 cleanup_exit(1);
1276         }
1277 #endif
1278
1279 skip:
1280
1281 #ifdef ENABLE_PKCS11
1282         pkcs11_init(0);
1283 #endif
1284         new_socket(AUTH_SOCKET, sock);
1285         if (ac > 0)
1286                 parent_alive_interval = 10;
1287         idtab_init();
1288         if (!d_flag)
1289                 signal(SIGINT, SIG_IGN);
1290         signal(SIGPIPE, SIG_IGN);
1291         signal(SIGHUP, cleanup_handler);
1292         signal(SIGTERM, cleanup_handler);
1293         nalloc = 0;
1294
1295         while (1) {
1296                 prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp);
1297                 result = select(max_fd + 1, readsetp, writesetp, NULL, tvp);
1298                 saved_errno = errno;
1299                 if (parent_alive_interval != 0)
1300                         check_parent_exists();
1301                 (void) reaper();        /* remove expired keys */
1302                 if (result < 0) {
1303                         if (saved_errno == EINTR)
1304                                 continue;
1305                         fatal("select: %s", strerror(saved_errno));
1306                 } else if (result > 0)
1307                         after_select(readsetp, writesetp);
1308         }
1309         /* NOTREACHED */
1310 }