sshconnect.c

   1 /* $OpenBSD: sshconnect.c,v 1.232 2011/01/16 11:50:36 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  * Code to connect to a remote host, and to perform the client side of the
   7  * login (authentication) dialog.
   8  *
   9  * As far as I am concerned, the code I have written for this software
  10  * can be used freely for any purpose.  Any derived versions of this
  11  * software must be clearly marked as such, and if the derived work is
  12  * incompatible with the protocol description in the RFC file, it must be
  13  * called by a name other than "ssh" or "Secure Shell".
  14  */
  15
  16 #include "includes.h"
  17
  18 #include <sys/types.h>
  19 #include <sys/wait.h>
  20 #include <sys/stat.h>
  21 #include <sys/socket.h>
  22 #ifdef HAVE_SYS_TIME_H
  23 # include <sys/time.h>
  24 #endif
  25
  26 #include <netinet/in.h>
  27 #include <arpa/inet.h>
  28
  29 #include <ctype.h>
  30 #include <errno.h>
  31 #include <fcntl.h>
  32 #include <netdb.h>
  33 #ifdef HAVE_PATHS_H
  34 #include <paths.h>
  35 #endif
  36 #include <pwd.h>
  37 #include <signal.h>
  38 #include <stdarg.h>
  39 #include <stdio.h>
  40 #include <stdlib.h>
  41 #include <string.h>
  42 #include <unistd.h>
  43
  44 #include "xmalloc.h"
  45 #include "key.h"
  46 #include "hostfile.h"
  47 #include "ssh.h"
  48 #include "rsa.h"
  49 #include "buffer.h"
  50 #include "packet.h"
  51 #include "uidswap.h"
  52 #include "compat.h"
  53 #include "key.h"
  54 #include "sshconnect.h"
  55 #include "hostfile.h"
  56 #include "log.h"
  57 #include "readconf.h"
  58 #include "atomicio.h"
  59 #include "misc.h"
  60 #include "dns.h"
  61 #include "roaming.h"
  62 #include "ssh2.h"
  63 #include "version.h"
  64
  65 char *client_version_string = NULL;
  66 char *server_version_string = NULL;
  67
  68 static int matching_host_key_dns = 0;
  69
  70 static pid_t proxy_command_pid = 0;
  71
  72 /* import */
  73 extern Options options;
  74 extern char *__progname;
  75 extern uid_t original_real_uid;
  76 extern uid_t original_effective_uid;
  77
  78 static int show_other_keys(struct hostkeys *, Key *);
  79 static void warn_changed_key(Key *);
  80
  81 /*
  82  * Connect to the given ssh server using a proxy command.
  83  */
  84 static int
  85 ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
  86 {
  87         char *command_string, *tmp;
  88         int pin[2], pout[2];
  89         pid_t pid;
  90         char *shell, strport[NI_MAXSERV];
  91
  92         if ((shell = getenv("SHELL")) == NULL || *shell == '\0')
  93                 shell = _PATH_BSHELL;
  94
  95         /* Convert the port number into a string. */
  96         snprintf(strport, sizeof strport, "%hu", port);
  97
  98         /*
  99          * Build the final command string in the buffer by making the
 100          * appropriate substitutions to the given proxy command.
 101          *
 102          * Use "exec" to avoid "sh -c" processes on some platforms
 103          * (e.g. Solaris)
 104          */
 105         xasprintf(&tmp, "exec %s", proxy_command);
 106         command_string = percent_expand(tmp, "h", host, "p", strport,
 107             "r", options.user, (char *)NULL);
 108         xfree(tmp);
 109
 110         /* Create pipes for communicating with the proxy. */
 111         if (pipe(pin) < 0 || pipe(pout) < 0)
 112                 fatal("Could not create pipes to communicate with the proxy: %.100s",
 113                     strerror(errno));
 114
 115         debug("Executing proxy command: %.500s", command_string);
 116
 117         /* Fork and execute the proxy command. */
 118         if ((pid = fork()) == 0) {
 119                 char *argv[10];
 120
 121                 /* Child.  Permanently give up superuser privileges. */
 122                 permanently_drop_suid(original_real_uid);
 123
 124                 /* Redirect stdin and stdout. */
 125                 close(pin[1]);
 126                 if (pin[0] != 0) {
 127                         if (dup2(pin[0], 0) < 0)
 128                                 perror("dup2 stdin");
 129                         close(pin[0]);
 130                 }
 131                 close(pout[0]);
 132                 if (dup2(pout[1], 1) < 0)
 133                         perror("dup2 stdout");
 134                 /* Cannot be 1 because pin allocated two descriptors. */
 135                 close(pout[1]);
 136
 137                 /* Stderr is left as it is so that error messages get
 138                    printed on the user's terminal. */
 139                 argv[0] = shell;
 140                 argv[1] = "-c";
 141                 argv[2] = command_string;
 142                 argv[3] = NULL;
 143
 144                 /* Execute the proxy command.  Note that we gave up any
 145                    extra privileges above. */
 146                 signal(SIGPIPE, SIG_DFL);
 147                 execv(argv[0], argv);
 148                 perror(argv[0]);
 149                 exit(1);
 150         }
 151         /* Parent. */
 152         if (pid < 0)
 153                 fatal("fork failed: %.100s", strerror(errno));
 154         else
 155                 proxy_command_pid = pid; /* save pid to clean up later */
 156
 157         /* Close child side of the descriptors. */
 158         close(pin[0]);
 159         close(pout[1]);
 160
 161         /* Free the command name. */
 162         xfree(command_string);
 163
 164         /* Set the connection file descriptors. */
 165         packet_set_connection(pout[0], pin[1]);
 166         packet_set_timeout(options.server_alive_interval,
 167             options.server_alive_count_max);
 168
 169         /* Indicate OK return */
 170         return 0;
 171 }
 172
 173 void
 174 ssh_kill_proxy_command(void)
 175 {
 176         /*
 177          * Send SIGHUP to proxy command if used. We don't wait() in
 178          * case it hangs and instead rely on init to reap the child
 179          */
 180         if (proxy_command_pid > 1)
 181                 kill(proxy_command_pid, SIGHUP);
 182 }
 183
 184 /*
 185  * Creates a (possibly privileged) socket for use as the ssh connection.
 186  */
 187 static int
 188 ssh_create_socket(int privileged, struct addrinfo *ai)
 189 {
 190         int sock, gaierr;
 191         struct addrinfo hints, *res;
 192
 193         /*
 194          * If we are running as root and want to connect to a privileged
 195          * port, bind our own socket to a privileged port.
 196          */
 197         if (privileged) {
 198                 int p = IPPORT_RESERVED - 1;
 199                 PRIV_START;
 200                 sock = rresvport_af(&p, ai->ai_family);
 201                 PRIV_END;
 202                 if (sock < 0)
 203                         error("rresvport: af=%d %.100s", ai->ai_family,
 204                             strerror(errno));
 205                 else
 206                         debug("Allocated local port %d.", p);
 207                 return sock;
 208         }
 209         sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 210         if (sock < 0) {
 211                 error("socket: %.100s", strerror(errno));
 212                 return -1;
 213         }
 214         fcntl(sock, F_SETFD, FD_CLOEXEC);
 215
 216         /* Bind the socket to an alternative local IP address */
 217         if (options.bind_address == NULL)
 218                 return sock;
 219
 220         memset(&hints, 0, sizeof(hints));
 221         hints.ai_family = ai->ai_family;
 222         hints.ai_socktype = ai->ai_socktype;
 223         hints.ai_protocol = ai->ai_protocol;
 224         hints.ai_flags = AI_PASSIVE;
 225         gaierr = getaddrinfo(options.bind_address, NULL, &hints, &res);
 226         if (gaierr) {
 227                 error("getaddrinfo: %s: %s", options.bind_address,
 228                     ssh_gai_strerror(gaierr));
 229                 close(sock);
 230                 return -1;
 231         }
 232         if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
 233                 error("bind: %s: %s", options.bind_address, strerror(errno));
 234                 close(sock);
 235                 freeaddrinfo(res);
 236                 return -1;
 237         }
 238         freeaddrinfo(res);
 239         return sock;
 240 }
 241
 242 static int
 243 timeout_connect(int sockfd, const struct sockaddr *serv_addr,
 244     socklen_t addrlen, int *timeoutp)
 245 {
 246         fd_set *fdset;
 247         struct timeval tv, t_start;
 248         socklen_t optlen;
 249         int optval, rc, result = -1;
 250
 251         gettimeofday(&t_start, NULL);
 252
 253         if (*timeoutp <= 0) {
 254                 result = connect(sockfd, serv_addr, addrlen);
 255                 goto done;
 256         }
 257
 258         set_nonblock(sockfd);
 259         rc = connect(sockfd, serv_addr, addrlen);
 260         if (rc == 0) {
 261                 unset_nonblock(sockfd);
 262                 result = 0;
 263                 goto done;
 264         }
 265         if (errno != EINPROGRESS) {
 266                 result = -1;
 267                 goto done;
 268         }
 269
 270         fdset = (fd_set *)xcalloc(howmany(sockfd + 1, NFDBITS),
 271             sizeof(fd_mask));
 272         FD_SET(sockfd, fdset);
 273         ms_to_timeval(&tv, *timeoutp);
 274
 275         for (;;) {
 276                 rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
 277                 if (rc != -1 || errno != EINTR)
 278                         break;
 279         }
 280
 281         switch (rc) {
 282         case 0:
 283                 /* Timed out */
 284                 errno = ETIMEDOUT;
 285                 break;
 286         case -1:
 287                 /* Select error */
 288                 debug("select: %s", strerror(errno));
 289                 break;
 290         case 1:
 291                 /* Completed or failed */
 292                 optval = 0;
 293                 optlen = sizeof(optval);
 294                 if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval,
 295                     &optlen) == -1) {
 296                         debug("getsockopt: %s", strerror(errno));
 297                         break;
 298                 }
 299                 if (optval != 0) {
 300                         errno = optval;
 301                         break;
 302                 }
 303                 result = 0;
 304                 unset_nonblock(sockfd);
 305                 break;
 306         default:
 307                 /* Should not occur */
 308                 fatal("Bogus return (%d) from select()", rc);
 309         }
 310
 311         xfree(fdset);
 312
 313  done:
 314         if (result == 0 && *timeoutp > 0) {
 315                 ms_subtract_diff(&t_start, timeoutp);
 316                 if (*timeoutp <= 0) {
 317                         errno = ETIMEDOUT;
 318                         result = -1;
 319                 }
 320         }
 321
 322         return (result);
 323 }
 324
 325 /*
 326  * Opens a TCP/IP connection to the remote server on the given host.
 327  * The address of the remote host will be returned in hostaddr.
 328  * If port is 0, the default port will be used.  If needpriv is true,
 329  * a privileged port will be allocated to make the connection.
 330  * This requires super-user privileges if needpriv is true.
 331  * Connection_attempts specifies the maximum number of tries (one per
 332  * second).  If proxy_command is non-NULL, it specifies the command (with %h
 333  * and %p substituted for host and port, respectively) to use to contact
 334  * the daemon.
 335  */
 336 int
 337 ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
 338     u_short port, int family, int connection_attempts, int *timeout_ms,
 339     int want_keepalive, int needpriv, const char *proxy_command)
 340 {
 341         int gaierr;
 342         int on = 1;
 343         int sock = -1, attempt;
 344         char ntop[NI_MAXHOST], strport[NI_MAXSERV];
 345         struct addrinfo hints, *ai, *aitop;
 346
 347         debug2("ssh_connect: needpriv %d", needpriv);
 348
 349         /* If a proxy command is given, connect using it. */
 350         if (proxy_command != NULL)
 351                 return ssh_proxy_connect(host, port, proxy_command);
 352
 353         /* No proxy command. */
 354
 355         memset(&hints, 0, sizeof(hints));
 356         hints.ai_family = family;
 357         hints.ai_socktype = SOCK_STREAM;
 358         snprintf(strport, sizeof strport, "%u", port);
 359         if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
 360                 fatal("%s: Could not resolve hostname %.100s: %s", __progname,
 361                     host, ssh_gai_strerror(gaierr));
 362
 363         for (attempt = 0; attempt < connection_attempts; attempt++) {
 364                 if (attempt > 0) {
 365                         /* Sleep a moment before retrying. */
 366                         sleep(1);
 367                         debug("Trying again...");
 368                 }
 369                 /*
 370                  * Loop through addresses for this host, and try each one in
 371                  * sequence until the connection succeeds.
 372                  */
 373                 for (ai = aitop; ai; ai = ai->ai_next) {
 374                         if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
 375                                 continue;
 376                         if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
 377                             ntop, sizeof(ntop), strport, sizeof(strport),
 378                             NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
 379                                 error("ssh_connect: getnameinfo failed");
 380                                 continue;
 381                         }
 382                         debug("Connecting to %.200s [%.100s] port %s.",
 383                                 host, ntop, strport);
 384
 385                         /* Create a socket for connecting. */
 386                         sock = ssh_create_socket(needpriv, ai);
 387                         if (sock < 0)
 388                                 /* Any error is already output */
 389                                 continue;
 390
 391                         if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
 392                             timeout_ms) >= 0) {
 393                                 /* Successful connection. */
 394                                 memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
 395                                 break;
 396                         } else {
 397                                 debug("connect to address %s port %s: %s",
 398                                     ntop, strport, strerror(errno));
 399                                 close(sock);
 400                                 sock = -1;
 401                         }
 402                 }
 403                 if (sock != -1)
 404                         break;  /* Successful connection. */
 405         }
 406
 407         freeaddrinfo(aitop);
 408
 409         /* Return failure if we didn't get a successful connection. */
 410         if (sock == -1) {
 411                 error("ssh: connect to host %s port %s: %s",
 412                     host, strport, strerror(errno));
 413                 return (-1);
 414         }
 415
 416         debug("Connection established.");
 417
 418         /* Set SO_KEEPALIVE if requested. */
 419         if (want_keepalive &&
 420             setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
 421             sizeof(on)) < 0)
 422                 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
 423
 424         /* Set the connection. */
 425         packet_set_connection(sock, sock);
 426         packet_set_timeout(options.server_alive_interval,
 427             options.server_alive_count_max);
 428
 429         return 0;
 430 }
 431
 432 /*
 433  * Waits for the server identification string, and sends our own
 434  * identification string.
 435  */
 436 void
 437 ssh_exchange_identification(int timeout_ms)
 438 {
 439         char buf[256], remote_version[256];     /* must be same size! */
 440         int remote_major, remote_minor, mismatch;
 441         int connection_in = packet_get_connection_in();
 442         int connection_out = packet_get_connection_out();
 443         int minor1 = PROTOCOL_MINOR_1;
 444         u_int i, n;
 445         size_t len;
 446         int fdsetsz, remaining, rc;
 447         struct timeval t_start, t_remaining;
 448         fd_set *fdset;
 449
 450         fdsetsz = howmany(connection_in + 1, NFDBITS) * sizeof(fd_mask);
 451         fdset = xcalloc(1, fdsetsz);
 452
 453         /* Read other side's version identification. */
 454         remaining = timeout_ms;
 455         for (n = 0;;) {
 456                 for (i = 0; i < sizeof(buf) - 1; i++) {
 457                         if (timeout_ms > 0) {
 458                                 gettimeofday(&t_start, NULL);
 459                                 ms_to_timeval(&t_remaining, remaining);
 460                                 FD_SET(connection_in, fdset);
 461                                 rc = select(connection_in + 1, fdset, NULL,
 462                                     fdset, &t_remaining);
 463                                 ms_subtract_diff(&t_start, &remaining);
 464                                 if (rc == 0 || remaining <= 0)
 465                                         fatal("Connection timed out during "
 466                                             "banner exchange");
 467                                 if (rc == -1) {
 468                                         if (errno == EINTR)
 469                                                 continue;
 470                                         fatal("ssh_exchange_identification: "
 471                                             "select: %s", strerror(errno));
 472                                 }
 473                         }
 474
 475                         len = roaming_atomicio(read, connection_in, &buf[i], 1);
 476
 477                         if (len != 1 && errno == EPIPE)
 478                                 fatal("ssh_exchange_identification: "
 479                                     "Connection closed by remote host");
 480                         else if (len != 1)
 481                                 fatal("ssh_exchange_identification: "
 482                                     "read: %.100s", strerror(errno));
 483                         if (buf[i] == '\r') {
 484                                 buf[i] = '\n';
 485                                 buf[i + 1] = 0;
 486                                 continue;               /**XXX wait for \n */
 487                         }
 488                         if (buf[i] == '\n') {
 489                                 buf[i + 1] = 0;
 490                                 break;
 491                         }
 492                         if (++n > 65536)
 493                                 fatal("ssh_exchange_identification: "
 494                                     "No banner received");
 495                 }
 496                 buf[sizeof(buf) - 1] = 0;
 497                 if (strncmp(buf, "SSH-", 4) == 0)
 498                         break;
 499                 debug("ssh_exchange_identification: %s", buf);
 500         }
 501         server_version_string = xstrdup(buf);
 502         xfree(fdset);
 503
 504         /*
 505          * Check that the versions match.  In future this might accept
 506          * several versions and set appropriate flags to handle them.
 507          */
 508         if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
 509             &remote_major, &remote_minor, remote_version) != 3)
 510                 fatal("Bad remote protocol version identification: '%.100s'", buf);
 511         debug("Remote protocol version %d.%d, remote software version %.100s",
 512             remote_major, remote_minor, remote_version);
 513
 514         compat_datafellows(remote_version);
 515         mismatch = 0;
 516
 517         switch (remote_major) {
 518         case 1:
 519                 if (remote_minor == 99 &&
 520                     (options.protocol & SSH_PROTO_2) &&
 521                     !(options.protocol & SSH_PROTO_1_PREFERRED)) {
 522                         enable_compat20();
 523                         break;
 524                 }
 525                 if (!(options.protocol & SSH_PROTO_1)) {
 526                         mismatch = 1;
 527                         break;
 528                 }
 529                 if (remote_minor < 3) {
 530                         fatal("Remote machine has too old SSH software version.");
 531                 } else if (remote_minor == 3 || remote_minor == 4) {
 532                         /* We speak 1.3, too. */
 533                         enable_compat13();
 534                         minor1 = 3;
 535                         if (options.forward_agent) {
 536                                 logit("Agent forwarding disabled for protocol 1.3");
 537                                 options.forward_agent = 0;
 538                         }
 539                 }
 540                 break;
 541         case 2:
 542                 if (options.protocol & SSH_PROTO_2) {
 543                         enable_compat20();
 544                         break;
 545                 }
 546                 /* FALLTHROUGH */
 547         default:
 548                 mismatch = 1;
 549                 break;
 550         }
 551         if (mismatch)
 552                 fatal("Protocol major versions differ: %d vs. %d",
 553                     (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
 554                     remote_major);
 555         /* Send our own protocol version identification. */
 556         snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s%s",
 557             compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
 558             compat20 ? PROTOCOL_MINOR_2 : minor1,
 559             SSH_VERSION, compat20 ? "\r\n" : "\n");
 560         if (roaming_atomicio(vwrite, connection_out, buf, strlen(buf))
 561             != strlen(buf))
 562                 fatal("write: %.100s", strerror(errno));
 563         client_version_string = xstrdup(buf);
 564         chop(client_version_string);
 565         chop(server_version_string);
 566         debug("Local version string %.100s", client_version_string);
 567 }
 568
 569 /* defaults to 'no' */
 570 static int
 571 confirm(const char *prompt)
 572 {
 573         const char *msg, *again = "Please type 'yes' or 'no': ";
 574         char *p;
 575         int ret = -1;
 576
 577         if (options.batch_mode)
 578                 return 0;
 579         for (msg = prompt;;msg = again) {
 580                 p = read_passphrase(msg, RP_ECHO);
 581                 if (p == NULL ||
 582                     (p[0] == '\0') || (p[0] == '\n') ||
 583                     strncasecmp(p, "no", 2) == 0)
 584                         ret = 0;
 585                 if (p && strncasecmp(p, "yes", 3) == 0)
 586                         ret = 1;
 587                 if (p)
 588                         xfree(p);
 589                 if (ret != -1)
 590                         return ret;
 591         }
 592 }
 593
 594 static int
 595 check_host_cert(const char *host, const Key *host_key)
 596 {
 597         const char *reason;
 598
 599         if (key_cert_check_authority(host_key, 1, 0, host, &reason) != 0) {
 600                 error("%s", reason);
 601                 return 0;
 602         }
 603         if (buffer_len(&host_key->cert->critical) != 0) {
 604                 error("Certificate for %s contains unsupported "
 605                     "critical options(s)", host);
 606                 return 0;
 607         }
 608         return 1;
 609 }
 610
 611 static int
 612 sockaddr_is_local(struct sockaddr *hostaddr)
 613 {
 614         switch (hostaddr->sa_family) {
 615         case AF_INET:
 616                 return (ntohl(((struct sockaddr_in *)hostaddr)->
 617                     sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
 618         case AF_INET6:
 619                 return IN6_IS_ADDR_LOOPBACK(
 620                     &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
 621         default:
 622                 return 0;
 623         }
 624 }
 625
 626 /*
 627  * Prepare the hostname and ip address strings that are used to lookup
 628  * host keys in known_hosts files. These may have a port number appended.
 629  */
 630 void
 631 get_hostfile_hostname_ipaddr(char *hostname, struct sockaddr *hostaddr,
 632     u_short port, char **hostfile_hostname, char **hostfile_ipaddr)
 633 {
 634         char ntop[NI_MAXHOST];
 635         socklen_t addrlen;
 636
 637         switch (hostaddr == NULL ? -1 : hostaddr->sa_family) {
 638         case -1:
 639                 addrlen = 0;
 640                 break;
 641         case AF_INET:
 642                 addrlen = sizeof(struct sockaddr_in);
 643                 break;
 644         case AF_INET6:
 645                 addrlen = sizeof(struct sockaddr_in6);
 646                 break;
 647         default:
 648                 addrlen = sizeof(struct sockaddr);
 649                 break;
 650         }
 651
 652         /*
 653          * We don't have the remote ip-address for connections
 654          * using a proxy command
 655          */
 656         if (hostfile_ipaddr != NULL) {
 657                 if (options.proxy_command == NULL) {
 658                         if (getnameinfo(hostaddr, addrlen,
 659                             ntop, sizeof(ntop), NULL, 0, NI_NUMERICHOST) != 0)
 660                         fatal("check_host_key: getnameinfo failed");
 661                         *hostfile_ipaddr = put_host_port(ntop, port);
 662                 } else {
 663                         *hostfile_ipaddr = xstrdup("<no hostip for proxy "
 664                             "command>");
 665                 }
 666         }
 667
 668         /*
 669          * Allow the user to record the key under a different name or
 670          * differentiate a non-standard port.  This is useful for ssh
 671          * tunneling over forwarded connections or if you run multiple
 672          * sshd's on different ports on the same machine.
 673          */
 674         if (hostfile_hostname != NULL) {
 675                 if (options.host_key_alias != NULL) {
 676                         *hostfile_hostname = xstrdup(options.host_key_alias);
 677                         debug("using hostkeyalias: %s", *hostfile_hostname);
 678                 } else {
 679                         *hostfile_hostname = put_host_port(hostname, port);
 680                 }
 681         }
 682 }
 683
 684 /*
 685  * check whether the supplied host key is valid, return -1 if the key
 686  * is not valid. the user_hostfile will not be updated if 'readonly' is true.
 687  */
 688 #define RDRW    0
 689 #define RDONLY  1
 690 #define ROQUIET 2
 691 static int
 692 check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port,
 693     Key *host_key, int readonly, char *user_hostfile,
 694     char *system_hostfile)
 695 {
 696         Key *raw_key = NULL;
 697         const char *type;
 698         char *ip = NULL, *host = NULL;
 699         char hostline[1000], *hostp, *fp, *ra;
 700         HostStatus host_status;
 701         HostStatus ip_status;
 702         int r, want_cert = key_is_cert(host_key), host_ip_differ = 0;
 703         int local = sockaddr_is_local(hostaddr);
 704         char msg[1024];
 705         int len, cancelled_forwarding = 0;
 706         struct hostkeys *host_hostkeys, *ip_hostkeys;
 707         const struct hostkey_entry *host_found, *ip_found;
 708
 709         /*
 710          * Force accepting of the host key for loopback/localhost. The
 711          * problem is that if the home directory is NFS-mounted to multiple
 712          * machines, localhost will refer to a different machine in each of
 713          * them, and the user will get bogus HOST_CHANGED warnings.  This
 714          * essentially disables host authentication for localhost; however,
 715          * this is probably not a real problem.
 716          */
 717         if (options.no_host_authentication_for_localhost == 1 && local &&
 718             options.host_key_alias == NULL) {
 719                 debug("Forcing accepting of host key for "
 720                     "loopback/localhost.");
 721                 return 0;
 722         }
 723
 724         /*
 725          * Prepare the hostname and address strings used for hostkey lookup.
 726          * In some cases, these will have a port number appended.
 727          */
 728         get_hostfile_hostname_ipaddr(hostname, hostaddr, port, &host, &ip);
 729
 730         /*
 731          * Turn off check_host_ip if the connection is to localhost, via proxy
 732          * command or if we don't have a hostname to compare with
 733          */
 734         if (options.check_host_ip && (local ||
 735             strcmp(hostname, ip) == 0 || options.proxy_command != NULL))
 736                 options.check_host_ip = 0;
 737
 738         host_hostkeys = init_hostkeys();
 739         load_hostkeys(host_hostkeys, host, user_hostfile);
 740         load_hostkeys(host_hostkeys, host, system_hostfile);
 741
 742         ip_hostkeys = NULL;
 743         if (!want_cert && options.check_host_ip) {
 744                 ip_hostkeys = init_hostkeys();
 745                 load_hostkeys(ip_hostkeys, ip, user_hostfile);
 746                 load_hostkeys(ip_hostkeys, ip, system_hostfile);
 747         }
 748
 749  retry:
 750         /* Reload these as they may have changed on cert->key downgrade */
 751         want_cert = key_is_cert(host_key);
 752         type = key_type(host_key);
 753
 754         /*
 755          * Check if the host key is present in the user's list of known
 756          * hosts or in the systemwide list.
 757          */
 758         host_status = check_key_in_hostkeys(host_hostkeys, host_key,
 759             &host_found);
 760
 761         /*
 762          * Also perform check for the ip address, skip the check if we are
 763          * localhost, looking for a certificate, or the hostname was an ip
 764          * address to begin with.
 765          */
 766         if (!want_cert && ip_hostkeys != NULL) {
 767                 ip_status = check_key_in_hostkeys(ip_hostkeys, host_key,
 768                     &ip_found);
 769                 if (host_status == HOST_CHANGED &&
 770                     (ip_status != HOST_CHANGED ||
 771                     (ip_found != NULL &&
 772                     !key_equal(ip_found->key, host_found->key))))
 773                         host_ip_differ = 1;
 774         } else
 775                 ip_status = host_status;
 776
 777         switch (host_status) {
 778         case HOST_OK:
 779                 /* The host is known and the key matches. */
 780                 debug("Host '%.200s' is known and matches the %s host %s.",
 781                     host, type, want_cert ? "certificate" : "key");
 782                 debug("Found %s in %s:%lu", want_cert ? "CA key" : "key",
 783                     host_found->file, host_found->line);
 784                 if (want_cert && !check_host_cert(hostname, host_key))
 785                         goto fail;
 786                 if (options.check_host_ip && ip_status == HOST_NEW) {
 787                         if (readonly || want_cert)
 788                                 logit("%s host key for IP address "
 789                                     "'%.128s' not in list of known hosts.",
 790                                     type, ip);
 791                         else if (!add_host_to_hostfile(user_hostfile, ip,
 792                             host_key, options.hash_known_hosts))
 793                                 logit("Failed to add the %s host key for IP "
 794                                     "address '%.128s' to the list of known "
 795                                     "hosts (%.30s).", type, ip, user_hostfile);
 796                         else
 797                                 logit("Warning: Permanently added the %s host "
 798                                     "key for IP address '%.128s' to the list "
 799                                     "of known hosts.", type, ip);
 800                 } else if (options.visual_host_key) {
 801                         fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
 802                         ra = key_fingerprint(host_key, SSH_FP_MD5,
 803                             SSH_FP_RANDOMART);
 804                         logit("Host key fingerprint is %s\n%s\n", fp, ra);
 805                         xfree(ra);
 806                         xfree(fp);
 807                 }
 808                 break;
 809         case HOST_NEW:
 810                 if (options.host_key_alias == NULL && port != 0 &&
 811                     port != SSH_DEFAULT_PORT) {
 812                         debug("checking without port identifier");
 813                         if (check_host_key(hostname, hostaddr, 0, host_key,
 814                             ROQUIET, user_hostfile, system_hostfile) == 0) {
 815                                 debug("found matching key w/out port");
 816                                 break;
 817                         }
 818                 }
 819                 if (readonly || want_cert)
 820                         goto fail;
 821                 /* The host is new. */
 822                 if (options.strict_host_key_checking == 1) {
 823                         /*
 824                          * User has requested strict host key checking.  We
 825                          * will not add the host key automatically.  The only
 826                          * alternative left is to abort.
 827                          */
 828                         error("No %s host key is known for %.200s and you "
 829                             "have requested strict checking.", type, host);
 830                         goto fail;
 831                 } else if (options.strict_host_key_checking == 2) {
 832                         char msg1[1024], msg2[1024];
 833
 834                         if (show_other_keys(host_hostkeys, host_key))
 835                                 snprintf(msg1, sizeof(msg1),
 836                                     "\nbut keys of different type are already"
 837                                     " known for this host.");
 838                         else
 839                                 snprintf(msg1, sizeof(msg1), ".");
 840                         /* The default */
 841                         fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
 842                         ra = key_fingerprint(host_key, SSH_FP_MD5,
 843                             SSH_FP_RANDOMART);
 844                         msg2[0] = '\0';
 845                         if (options.verify_host_key_dns) {
 846                                 if (matching_host_key_dns)
 847                                         snprintf(msg2, sizeof(msg2),
 848                                             "Matching host key fingerprint"
 849                                             " found in DNS.\n");
 850                                 else
 851                                         snprintf(msg2, sizeof(msg2),
 852                                             "No matching host key fingerprint"
 853                                             " found in DNS.\n");
 854                         }
 855                         snprintf(msg, sizeof(msg),
 856                             "The authenticity of host '%.200s (%s)' can't be "
 857                             "established%s\n"
 858                             "%s key fingerprint is %s.%s%s\n%s"
 859                             "Are you sure you want to continue connecting "
 860                             "(yes/no)? ",
 861                             host, ip, msg1, type, fp,
 862                             options.visual_host_key ? "\n" : "",
 863                             options.visual_host_key ? ra : "",
 864                             msg2);
 865                         xfree(ra);
 866                         xfree(fp);
 867                         if (!confirm(msg))
 868                                 goto fail;
 869                 }
 870                 /*
 871                  * If not in strict mode, add the key automatically to the
 872                  * local known_hosts file.
 873                  */
 874                 if (options.check_host_ip && ip_status == HOST_NEW) {
 875                         snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
 876                         hostp = hostline;
 877                         if (options.hash_known_hosts) {
 878                                 /* Add hash of host and IP separately */
 879                                 r = add_host_to_hostfile(user_hostfile, host,
 880                                     host_key, options.hash_known_hosts) &&
 881                                     add_host_to_hostfile(user_hostfile, ip,
 882                                     host_key, options.hash_known_hosts);
 883                         } else {
 884                                 /* Add unhashed "host,ip" */
 885                                 r = add_host_to_hostfile(user_hostfile,
 886                                     hostline, host_key,
 887                                     options.hash_known_hosts);
 888                         }
 889                 } else {
 890                         r = add_host_to_hostfile(user_hostfile, host, host_key,
 891                             options.hash_known_hosts);
 892                         hostp = host;
 893                 }
 894
 895                 if (!r)
 896                         logit("Failed to add the host to the list of known "
 897                             "hosts (%.500s).", user_hostfile);
 898                 else
 899                         logit("Warning: Permanently added '%.200s' (%s) to the "
 900                             "list of known hosts.", hostp, type);
 901                 break;
 902         case HOST_REVOKED:
 903                 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
 904                 error("@       WARNING: REVOKED HOST KEY DETECTED!               @");
 905                 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
 906                 error("The %s host key for %s is marked as revoked.", type, host);
 907                 error("This could mean that a stolen key is being used to");
 908                 error("impersonate this host.");
 909
 910                 /*
 911                  * If strict host key checking is in use, the user will have
 912                  * to edit the key manually and we can only abort.
 913                  */
 914                 if (options.strict_host_key_checking) {
 915                         error("%s host key for %.200s was revoked and you have "
 916                             "requested strict checking.", type, host);
 917                         goto fail;
 918                 }
 919                 goto continue_unsafe;
 920
 921         case HOST_CHANGED:
 922                 if (want_cert) {
 923                         /*
 924                          * This is only a debug() since it is valid to have
 925                          * CAs with wildcard DNS matches that don't match
 926                          * all hosts that one might visit.
 927                          */
 928                         debug("Host certificate authority does not "
 929                             "match %s in %s:%lu", CA_MARKER,
 930                             host_found->file, host_found->line);
 931                         goto fail;
 932                 }
 933                 if (readonly == ROQUIET)
 934                         goto fail;
 935                 if (options.check_host_ip && host_ip_differ) {
 936                         char *key_msg;
 937                         if (ip_status == HOST_NEW)
 938                                 key_msg = "is unknown";
 939                         else if (ip_status == HOST_OK)
 940                                 key_msg = "is unchanged";
 941                         else
 942                                 key_msg = "has a different value";
 943                         error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
 944                         error("@       WARNING: POSSIBLE DNS SPOOFING DETECTED!          @");
 945                         error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
 946                         error("The %s host key for %s has changed,", type, host);
 947                         error("and the key for the corresponding IP address %s", ip);
 948                         error("%s. This could either mean that", key_msg);
 949                         error("DNS SPOOFING is happening or the IP address for the host");
 950                         error("and its host key have changed at the same time.");
 951                         if (ip_status != HOST_NEW)
 952                                 error("Offending key for IP in %s:%lu",
 953                                     ip_found->file, ip_found->line);
 954                 }
 955                 /* The host key has changed. */
 956                 warn_changed_key(host_key);
 957                 error("Add correct host key in %.100s to get rid of this message.",
 958                     user_hostfile);
 959                 error("Offending %s key in %s:%lu", key_type(host_found->key),
 960                     host_found->file, host_found->line);
 961
 962                 /*
 963                  * If strict host key checking is in use, the user will have
 964                  * to edit the key manually and we can only abort.
 965                  */
 966                 if (options.strict_host_key_checking) {
 967                         error("%s host key for %.200s has changed and you have "
 968                             "requested strict checking.", type, host);
 969                         goto fail;
 970                 }
 971
 972  continue_unsafe:
 973                 /*
 974                  * If strict host key checking has not been requested, allow
 975                  * the connection but without MITM-able authentication or
 976                  * forwarding.
 977                  */
 978                 if (options.password_authentication) {
 979                         error("Password authentication is disabled to avoid "
 980                             "man-in-the-middle attacks.");
 981                         options.password_authentication = 0;
 982                         cancelled_forwarding = 1;
 983                 }
 984                 if (options.kbd_interactive_authentication) {
 985                         error("Keyboard-interactive authentication is disabled"
 986                             " to avoid man-in-the-middle attacks.");
 987                         options.kbd_interactive_authentication = 0;
 988                         options.challenge_response_authentication = 0;
 989                         cancelled_forwarding = 1;
 990                 }
 991                 if (options.challenge_response_authentication) {
 992                         error("Challenge/response authentication is disabled"
 993                             " to avoid man-in-the-middle attacks.");
 994                         options.challenge_response_authentication = 0;
 995                         cancelled_forwarding = 1;
 996                 }
 997                 if (options.forward_agent) {
 998                         error("Agent forwarding is disabled to avoid "
 999                             "man-in-the-middle attacks.");
1000                         options.forward_agent = 0;
1001                         cancelled_forwarding = 1;
1002                 }
1003                 if (options.forward_x11) {
1004                         error("X11 forwarding is disabled to avoid "
1005                             "man-in-the-middle attacks.");
1006                         options.forward_x11 = 0;
1007                         cancelled_forwarding = 1;
1008                 }
1009                 if (options.num_local_forwards > 0 ||
1010                     options.num_remote_forwards > 0) {
1011                         error("Port forwarding is disabled to avoid "
1012                             "man-in-the-middle attacks.");
1013                         options.num_local_forwards =
1014                             options.num_remote_forwards = 0;
1015                         cancelled_forwarding = 1;
1016                 }
1017                 if (options.tun_open != SSH_TUNMODE_NO) {
1018                         error("Tunnel forwarding is disabled to avoid "
1019                             "man-in-the-middle attacks.");
1020                         options.tun_open = SSH_TUNMODE_NO;
1021                         cancelled_forwarding = 1;
1022                 }
1023                 if (options.exit_on_forward_failure && cancelled_forwarding)
1024                         fatal("Error: forwarding disabled due to host key "
1025                             "check failure");
1026
1027                 /*
1028                  * XXX Should permit the user to change to use the new id.
1029                  * This could be done by converting the host key to an
1030                  * identifying sentence, tell that the host identifies itself
1031                  * by that sentence, and ask the user if he/she wishes to
1032                  * accept the authentication.
1033                  */
1034                 break;
1035         case HOST_FOUND:
1036                 fatal("internal error");
1037                 break;
1038         }
1039
1040         if (options.check_host_ip && host_status != HOST_CHANGED &&
1041             ip_status == HOST_CHANGED) {
1042                 snprintf(msg, sizeof(msg),
1043                     "Warning: the %s host key for '%.200s' "
1044                     "differs from the key for the IP address '%.128s'"
1045                     "\nOffending key for IP in %s:%lu",
1046                     type, host, ip, ip_found->file, ip_found->line);
1047                 if (host_status == HOST_OK) {
1048                         len = strlen(msg);
1049                         snprintf(msg + len, sizeof(msg) - len,
1050                             "\nMatching host key in %s:%lu",
1051                             host_found->file, host_found->line);
1052                 }
1053                 if (options.strict_host_key_checking == 1) {
1054                         logit("%s", msg);
1055                         error("Exiting, you have requested strict checking.");
1056                         goto fail;
1057                 } else if (options.strict_host_key_checking == 2) {
1058                         strlcat(msg, "\nAre you sure you want "
1059                             "to continue connecting (yes/no)? ", sizeof(msg));
1060                         if (!confirm(msg))
1061                                 goto fail;
1062                 } else {
1063                         logit("%s", msg);
1064                 }
1065         }
1066
1067         xfree(ip);
1068         xfree(host);
1069         if (host_hostkeys != NULL)
1070                 free_hostkeys(host_hostkeys);
1071         if (ip_hostkeys != NULL)
1072                 free_hostkeys(ip_hostkeys);
1073         return 0;
1074
1075 fail:
1076         if (want_cert && host_status != HOST_REVOKED) {
1077                 /*
1078                  * No matching certificate. Downgrade cert to raw key and
1079                  * search normally.
1080                  */
1081                 debug("No matching CA found. Retry with plain key");
1082                 raw_key = key_from_private(host_key);
1083                 if (key_drop_cert(raw_key) != 0)
1084                         fatal("Couldn't drop certificate");
1085                 host_key = raw_key;
1086                 goto retry;
1087         }
1088         if (raw_key != NULL)
1089                 key_free(raw_key);
1090         xfree(ip);
1091         xfree(host);
1092         if (host_hostkeys != NULL)
1093                 free_hostkeys(host_hostkeys);
1094         if (ip_hostkeys != NULL)
1095                 free_hostkeys(ip_hostkeys);
1096         return -1;
1097 }
1098
1099 /* returns 0 if key verifies or -1 if key does NOT verify */
1100 int
1101 verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
1102 {
1103         struct stat st;
1104         int flags = 0;
1105         char *fp;
1106
1107         fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1108         debug("Server host key: %s %s", key_type(host_key), fp);
1109         xfree(fp);
1110
1111         /* XXX certs are not yet supported for DNS */
1112         if (!key_is_cert(host_key) && options.verify_host_key_dns &&
1113             verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
1114
1115                 if (flags & DNS_VERIFY_FOUND) {
1116
1117                         if (options.verify_host_key_dns == 1 &&
1118                             flags & DNS_VERIFY_MATCH &&
1119                             flags & DNS_VERIFY_SECURE)
1120                                 return 0;
1121
1122                         if (flags & DNS_VERIFY_MATCH) {
1123                                 matching_host_key_dns = 1;
1124                         } else {
1125                                 warn_changed_key(host_key);
1126                                 error("Update the SSHFP RR in DNS with the new "
1127                                     "host key to get rid of this message.");
1128                         }
1129                 }
1130         }
1131
1132         /* return ok if the key can be found in an old keyfile */
1133         if (stat(options.system_hostfile2, &st) == 0 ||
1134             stat(options.user_hostfile2, &st) == 0) {
1135                 if (check_host_key(host, hostaddr, options.port, host_key,
1136                     RDONLY, options.user_hostfile2,
1137                     options.system_hostfile2) == 0)
1138                         return 0;
1139         }
1140         return check_host_key(host, hostaddr, options.port, host_key,
1141             RDRW, options.user_hostfile, options.system_hostfile);
1142 }
1143
1144 /*
1145  * Starts a dialog with the server, and authenticates the current user on the
1146  * server.  This does not need any extra privileges.  The basic connection
1147  * to the server must already have been established before this is called.
1148  * If login fails, this function prints an error and never returns.
1149  * This function does not require super-user privileges.
1150  */
1151 void
1152 ssh_login(Sensitive *sensitive, const char *orighost,
1153     struct sockaddr *hostaddr, u_short port, struct passwd *pw, int timeout_ms)
1154 {
1155         char *host, *cp;
1156         char *server_user, *local_user;
1157
1158         local_user = xstrdup(pw->pw_name);
1159         server_user = options.user ? options.user : local_user;
1160
1161         /* Convert the user-supplied hostname into all lowercase. */
1162         host = xstrdup(orighost);
1163         for (cp = host; *cp; cp++)
1164                 if (isupper(*cp))
1165                         *cp = (char)tolower(*cp);
1166
1167         /* Exchange protocol version identification strings with the server. */
1168         ssh_exchange_identification(timeout_ms);
1169
1170         /* Put the connection into non-blocking mode. */
1171         packet_set_nonblocking();
1172
1173         /* key exchange */
1174         /* authenticate user */
1175         if (compat20) {
1176                 ssh_kex2(host, hostaddr, port);
1177                 ssh_userauth2(local_user, server_user, host, sensitive);
1178         } else {
1179                 ssh_kex(host, hostaddr);
1180                 ssh_userauth1(local_user, server_user, host, sensitive);
1181         }
1182         xfree(local_user);
1183 }
1184
1185 void
1186 ssh_put_password(char *password)
1187 {
1188         int size;
1189         char *padded;
1190
1191         if (datafellows & SSH_BUG_PASSWORDPAD) {
1192                 packet_put_cstring(password);
1193                 return;
1194         }
1195         size = roundup(strlen(password) + 1, 32);
1196         padded = xcalloc(1, size);
1197         strlcpy(padded, password, size);
1198         packet_put_string(padded, size);
1199         memset(padded, 0, size);
1200         xfree(padded);
1201 }
1202
1203 /* print all known host keys for a given host, but skip keys of given type */
1204 static int
1205 show_other_keys(struct hostkeys *hostkeys, Key *key)
1206 {
1207         int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, KEY_ECDSA, -1};
1208         int i, ret = 0;
1209         char *fp, *ra;
1210         const struct hostkey_entry *found;
1211
1212         for (i = 0; type[i] != -1; i++) {
1213                 if (type[i] == key->type)
1214                         continue;
1215                 if (!lookup_key_in_hostkeys_by_type(hostkeys, type[i], &found))
1216                         continue;
1217                 fp = key_fingerprint(found->key, SSH_FP_MD5, SSH_FP_HEX);
1218                 ra = key_fingerprint(found->key, SSH_FP_MD5, SSH_FP_RANDOMART);
1219                 logit("WARNING: %s key found for host %s\n"
1220                     "in %s:%lu\n"
1221                     "%s key fingerprint %s.",
1222                     key_type(found->key),
1223                     found->host, found->file, found->line,
1224                     key_type(found->key), fp);
1225                 if (options.visual_host_key)
1226                         logit("%s", ra);
1227                 xfree(ra);
1228                 xfree(fp);
1229                 ret = 1;
1230         }
1231         return ret;
1232 }
1233
1234 static void
1235 warn_changed_key(Key *host_key)
1236 {
1237         char *fp;
1238
1239         fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1240
1241         error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1242         error("@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @");
1243         error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1244         error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
1245         error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
1246         error("It is also possible that a host key has just been changed.");
1247         error("The fingerprint for the %s key sent by the remote host is\n%s.",
1248             key_type(host_key), fp);
1249         error("Please contact your system administrator.");
1250
1251         xfree(fp);
1252 }
1253
1254 /*
1255  * Execute a local command
1256  */
1257 int
1258 ssh_local_cmd(const char *args)
1259 {
1260         char *shell;
1261         pid_t pid;
1262         int status;
1263         void (*osighand)(int);
1264
1265         if (!options.permit_local_command ||
1266             args == NULL || !*args)
1267                 return (1);
1268
1269         if ((shell = getenv("SHELL")) == NULL || *shell == '\0')
1270                 shell = _PATH_BSHELL;
1271
1272         osighand = signal(SIGCHLD, SIG_DFL);
1273         pid = fork();
1274         if (pid == 0) {
1275                 signal(SIGPIPE, SIG_DFL);
1276                 debug3("Executing %s -c \"%s\"", shell, args);
1277                 execl(shell, shell, "-c", args, (char *)NULL);
1278                 error("Couldn't execute %s -c \"%s\": %s",
1279                     shell, args, strerror(errno));
1280                 _exit(1);
1281         } else if (pid == -1)
1282                 fatal("fork failed: %.100s", strerror(errno));
1283         while (waitpid(pid, &status, 0) == -1)
1284                 if (errno != EINTR)
1285                         fatal("Couldn't wait for child: %s", strerror(errno));
1286         signal(SIGCHLD, osighand);
1287
1288         if (!WIFEXITED(status))
1289                 return (1);
1290
1291         return (WEXITSTATUS(status));
1292 }