1 /* $OpenBSD: sshconnect.c,v 1.263 2015/08/20 22:32:42 deraadt 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 #ifndef WIN32 19 #include <sys/param.h> /* roundup */ 20 #endif 21 #include <sys/types.h> 22 23 #ifndef WIN32 24 #include <sys/wait.h> 25 #endif 26 #include <sys/stat.h> 27 #ifndef WIN32 28 #include <sys/socket.h> 29 #endif 30 #ifdef HAVE_SYS_TIME_H 31 # include <sys/time.h> 32 #endif 33 34 #ifndef WIN32 35 #include <netinet/in.h> 36 #include <arpa/inet.h> 37 #endif 38 39 #include <ctype.h> 40 #include <errno.h> 41 #include <fcntl.h> 42 #ifndef WIN32 43 #include <netdb.h> 44 #endif 45 #ifdef HAVE_PATHS_H 46 #include <paths.h> 47 #endif 48 #ifndef WIN32 49 #include <pwd.h> 50 #endif 51 #include <signal.h> 52 #include <stdarg.h> 53 #include <stdio.h> 54 #include <stdlib.h> 55 #include <string.h> 56 #ifndef WIN32 57 #include <unistd.h> 58 #endif 59 60 #include "xmalloc.h" 61 #include "key.h" 62 #include "hostfile.h" 63 #include "ssh.h" 64 #include "rsa.h" 65 #include "buffer.h" 66 #include "packet.h" 67 #include "uidswap.h" 68 #include "compat.h" 69 #include "key.h" 70 #include "sshconnect.h" 71 #include "hostfile.h" 72 #include "log.h" 73 #include "misc.h" 74 #include "readconf.h" 75 #ifndef WIN32 76 #include "atomicio.h" 77 #endif 78 79 #ifndef WIN32 80 #include "dns.h" 81 #include "roaming.h" 82 #include "monitor_fdpass.h" 83 #endif 84 #include "ssh2.h" 85 #ifndef WIN32 86 #include "version.h" 87 #endif 88 #include "authfile.h" 89 #include "ssherr.h" 90 91 char *client_version_string = NULL; 92 char *server_version_string = NULL; 93 Key *previous_host_key = NULL; 94 95 static int matching_host_key_dns = 0; 96 97 static pid_t proxy_command_pid = 0; 98 99 /* import */ 100 extern Options options; 101 extern char *__progname; 102 extern uid_t original_real_uid; 103 extern uid_t original_effective_uid; 104 105 static int show_other_keys(struct hostkeys *, Key *); 106 static void warn_changed_key(Key *); 107 108 #if 0 109 110 /* Expand a proxy command */ 111 static char * 112 expand_proxy_command(const char *proxy_command, const char *user, 113 const char *host, int port) 114 { 115 char *tmp, *ret, strport[NI_MAXSERV]; 116 117 snprintf(strport, sizeof strport, "%d", port); 118 xasprintf(&tmp, "exec %s", proxy_command); 119 ret = percent_expand(tmp, "h", host, "p", strport, 120 "r", options.user, (char *)NULL); 121 free(tmp); 122 return ret; 123 } 124 125 /* 126 * Connect to the given ssh server using a proxy command that passes a 127 * a connected fd back to us. 128 */ 129 static int 130 ssh_proxy_fdpass_connect(const char *host, u_short port, 131 const char *proxy_command) 132 { 133 char *command_string; 134 int sp[2], sock; 135 pid_t pid; 136 char *shell; 137 138 if ((shell = getenv("SHELL")) == NULL) 139 shell = _PATH_BSHELL; 140 141 if (socketpair(AF_UNIX, SOCK_STREAM, 0, sp) < 0) 142 fatal("Could not create socketpair to communicate with " 143 "proxy dialer: %.100s", strerror(errno)); 144 145 command_string = expand_proxy_command(proxy_command, options.user, 146 host, port); 147 debug("Executing proxy dialer command: %.500s", command_string); 148 149 /* Fork and execute the proxy command. */ 150 if ((pid = fork()) == 0) { 151 char *argv[10]; 152 153 /* Child. Permanently give up superuser privileges. */ 154 permanently_drop_suid(original_real_uid); 155 156 close(sp[1]); 157 /* Redirect stdin and stdout. */ 158 if (sp[0] != 0) { 159 if (dup2(sp[0], 0) < 0) 160 perror("dup2 stdin"); 161 } 162 if (sp[0] != 1) { 163 if (dup2(sp[0], 1) < 0) 164 perror("dup2 stdout"); 165 } 166 if (sp[0] >= 2) 167 close(sp[0]); 168 169 /* 170 * Stderr is left as it is so that error messages get 171 * printed on the user's terminal. 172 */ 173 argv[0] = shell; 174 argv[1] = "-c"; 175 argv[2] = command_string; 176 argv[3] = NULL; 177 178 /* 179 * Execute the proxy command. 180 * Note that we gave up any extra privileges above. 181 */ 182 execv(argv[0], argv); 183 perror(argv[0]); 184 exit(1); 185 } 186 /* Parent. */ 187 if (pid < 0) 188 fatal("fork failed: %.100s", strerror(errno)); 189 close(sp[0]); 190 free(command_string); 191 192 if ((sock = mm_receive_fd(sp[1])) == -1) 193 fatal("proxy dialer did not pass back a connection"); 194 195 while (waitpid(pid, NULL, 0) == -1) 196 if (errno != EINTR) 197 fatal("Couldn't wait for child: %s", strerror(errno)); 198 199 /* Set the connection file descriptors. */ 200 packet_set_connection(sock, sock); 201 202 return 0; 203 } 204 205 /* 206 * Connect to the given ssh server using a proxy command. 207 */ 208 static int 209 ssh_proxy_connect(const char *host, u_short port, const char *proxy_command) 210 { 211 char *command_string; 212 int pin[2], pout[2]; 213 pid_t pid; 214 char *shell; 215 216 if ((shell = getenv("SHELL")) == NULL || *shell == '\0') 217 shell = _PATH_BSHELL; 218 219 /* Create pipes for communicating with the proxy. */ 220 if (pipe(pin) < 0 || pipe(pout) < 0) 221 fatal("Could not create pipes to communicate with the proxy: %.100s", 222 strerror(errno)); 223 224 command_string = expand_proxy_command(proxy_command, options.user, 225 host, port); 226 debug("Executing proxy command: %.500s", command_string); 227 228 /* Fork and execute the proxy command. */ 229 if ((pid = fork()) == 0) { 230 char *argv[10]; 231 232 /* Child. Permanently give up superuser privileges. */ 233 permanently_drop_suid(original_real_uid); 234 235 /* Redirect stdin and stdout. */ 236 close(pin[1]); 237 if (pin[0] != 0) { 238 if (dup2(pin[0], 0) < 0) 239 perror("dup2 stdin"); 240 close(pin[0]); 241 } 242 close(pout[0]); 243 if (dup2(pout[1], 1) < 0) 244 perror("dup2 stdout"); 245 /* Cannot be 1 because pin allocated two descriptors. */ 246 close(pout[1]); 247 248 /* Stderr is left as it is so that error messages get 249 printed on the user's terminal. */ 250 argv[0] = shell; 251 argv[1] = "-c"; 252 argv[2] = command_string; 253 argv[3] = NULL; 254 255 /* Execute the proxy command. Note that we gave up any 256 extra privileges above. */ 257 signal(SIGPIPE, SIG_DFL); 258 execv(argv[0], argv); 259 perror(argv[0]); 260 exit(1); 261 } 262 /* Parent. */ 263 if (pid < 0) 264 fatal("fork failed: %.100s", strerror(errno)); 265 else 266 proxy_command_pid = pid; /* save pid to clean up later */ 267 268 /* Close child side of the descriptors. */ 269 close(pin[0]); 270 close(pout[1]); 271 272 /* Free the command name. */ 273 free(command_string); 274 275 /* Set the connection file descriptors. */ 276 packet_set_connection(pout[0], pin[1]); 277 278 /* Indicate OK return */ 279 return 0; 280 } 281 282 void 283 ssh_kill_proxy_command(void) 284 { 285 /* 286 * Send SIGHUP to proxy command if used. We don't wait() in 287 * case it hangs and instead rely on init to reap the child 288 */ 289 if (proxy_command_pid > 1) 290 kill(proxy_command_pid, SIGHUP); 291 } 292 293 /* 294 * Creates a (possibly privileged) socket for use as the ssh connection. 295 */ 296 static int 297 ssh_create_socket(int privileged, struct addrinfo *ai) 298 { 299 int sock, r, gaierr; 300 struct addrinfo hints, *res = NULL; 301 302 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 303 if (sock < 0) { 304 ssh_error("socket: %s", strerror(errno)); 305 return -1; 306 } 307 fcntl(sock, F_SETFD, FD_CLOEXEC); 308 309 /* Bind the socket to an alternative local IP address */ 310 if (options.bind_address == NULL && !privileged) 311 return sock; 312 313 if (options.bind_address) { 314 memset(&hints, 0, sizeof(hints)); 315 hints.ai_family = ai->ai_family; 316 hints.ai_socktype = ai->ai_socktype; 317 hints.ai_protocol = ai->ai_protocol; 318 hints.ai_flags = AI_PASSIVE; 319 gaierr = getaddrinfo(options.bind_address, NULL, &hints, &res); 320 if (gaierr) { 321 ssh_error("getaddrinfo: %s: %s", options.bind_address, 322 ssh_gai_strerror(gaierr)); 323 close(sock); 324 return -1; 325 } 326 } 327 /* 328 * If we are running as root and want to connect to a privileged 329 * port, bind our own socket to a privileged port. 330 */ 331 if (privileged) { 332 PRIV_START; 333 r = bindresvport_sa(sock, res ? res->ai_addr : NULL); 334 PRIV_END; 335 if (r < 0) { 336 ssh_error("bindresvport_sa: af=%d %s", ai->ai_family, 337 strerror(errno)); 338 goto fail; 339 } 340 } else { 341 if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) { 342 ssh_error("bind: %s: %s", options.bind_address, 343 strerror(errno)); 344 fail: 345 close(sock); 346 freeaddrinfo(res); 347 return -1; 348 } 349 } 350 if (res != NULL) 351 freeaddrinfo(res); 352 return sock; 353 } 354 355 static int 356 timeout_connect(int sockfd, const struct sockaddr *serv_addr, 357 socklen_t addrlen, int *timeoutp) 358 { 359 fd_set *fdset; 360 struct timeval tv, t_start; 361 socklen_t optlen; 362 int optval, rc, result = -1; 363 364 gettimeofday(&t_start, NULL); 365 366 if (*timeoutp <= 0) { 367 result = connect(sockfd, serv_addr, addrlen); 368 goto done; 369 } 370 371 set_nonblock(sockfd); 372 rc = connect(sockfd, serv_addr, addrlen); 373 if (rc == 0) { 374 unset_nonblock(sockfd); 375 result = 0; 376 goto done; 377 } 378 if (errno != EINPROGRESS) { 379 result = -1; 380 goto done; 381 } 382 383 fdset = xcalloc(howmany(sockfd + 1, NFDBITS), 384 sizeof(fd_mask)); 385 FD_SET(sockfd, fdset); 386 ms_to_timeval(&tv, *timeoutp); 387 388 for (;;) { 389 rc = select(sockfd + 1, NULL, fdset, NULL, &tv); 390 if (rc != -1 || errno != EINTR) 391 break; 392 } 393 394 switch (rc) { 395 case 0: 396 /* Timed out */ 397 errno = ETIMEDOUT; 398 break; 399 case -1: 400 /* Select error */ 401 debug("select: %s", strerror(errno)); 402 break; 403 case 1: 404 /* Completed or failed */ 405 optval = 0; 406 optlen = sizeof(optval); 407 if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval, 408 &optlen) == -1) { 409 debug("getsockopt: %s", strerror(errno)); 410 break; 411 } 412 if (optval != 0) { 413 errno = optval; 414 break; 415 } 416 result = 0; 417 unset_nonblock(sockfd); 418 break; 419 default: 420 /* Should not occur */ 421 fatal("Bogus return (%d) from select()", rc); 422 } 423 424 free(fdset); 425 426 done: 427 if (result == 0 && *timeoutp > 0) { 428 ms_subtract_diff(&t_start, timeoutp); 429 if (*timeoutp <= 0) { 430 errno = ETIMEDOUT; 431 result = -1; 432 } 433 } 434 435 return (result); 436 } 437 438 /* 439 * Opens a TCP/IP connection to the remote server on the given host. 440 * The address of the remote host will be returned in hostaddr. 441 * If port is 0, the default port will be used. If needpriv is true, 442 * a privileged port will be allocated to make the connection. 443 * This requires super-user privileges if needpriv is true. 444 * Connection_attempts specifies the maximum number of tries (one per 445 * second). If proxy_command is non-NULL, it specifies the command (with %h 446 * and %p substituted for host and port, respectively) to use to contact 447 * the daemon. 448 */ 449 static int 450 ssh_connect_direct(const char *host, struct addrinfo *aitop, 451 struct sockaddr_storage *hostaddr, u_short port, int family, 452 int connection_attempts, int *timeout_ms, int want_keepalive, int needpriv) 453 { 454 int on = 1; 455 int sock = -1, attempt; 456 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 457 struct addrinfo *ai; 458 459 debug2("ssh_connect: needpriv %d", needpriv); 460 461 for (attempt = 0; attempt < connection_attempts; attempt++) { 462 if (attempt > 0) { 463 /* Sleep a moment before retrying. */ 464 sleep(1); 465 debug("Trying again..."); 466 } 467 /* 468 * Loop through addresses for this host, and try each one in 469 * sequence until the connection succeeds. 470 */ 471 for (ai = aitop; ai; ai = ai->ai_next) { 472 if (ai->ai_family != AF_INET && 473 ai->ai_family != AF_INET6) 474 continue; 475 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, 476 ntop, sizeof(ntop), strport, sizeof(strport), 477 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 478 ssh_error("ssh_connect: getnameinfo failed"); 479 continue; 480 } 481 debug("Connecting to %.200s [%.100s] port %s.", 482 host, ntop, strport); 483 484 /* Create a socket for connecting. */ 485 sock = ssh_create_socket(needpriv, ai); 486 if (sock < 0) 487 /* Any error is already output */ 488 continue; 489 490 if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen, 491 timeout_ms) >= 0) { 492 /* Successful connection. */ 493 memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen); 494 break; 495 } else { 496 debug("connect to address %s port %s: %s", 497 ntop, strport, strerror(errno)); 498 close(sock); 499 sock = -1; 500 } 501 } 502 if (sock != -1) 503 break; /* Successful connection. */ 504 } 505 506 /* Return failure if we didn't get a successful connection. */ 507 if (sock == -1) { 508 ssh_error("ssh: connect to host %s port %s: %s", 509 host, strport, strerror(errno)); 510 return (-1); 511 } 512 513 debug("Connection established."); 514 515 /* Set SO_KEEPALIVE if requested. */ 516 if (want_keepalive && 517 setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on, 518 sizeof(on)) < 0) 519 ssh_error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); 520 521 /* Set the connection. */ 522 packet_set_connection(sock, sock); 523 524 return 0; 525 } 526 527 int 528 ssh_connect(const char *host, struct addrinfo *addrs, 529 struct sockaddr_storage *hostaddr, u_short port, int family, 530 int connection_attempts, int *timeout_ms, int want_keepalive, int needpriv) 531 { 532 if (options.proxy_command == NULL) { 533 return ssh_connect_direct(host, addrs, hostaddr, port, family, 534 connection_attempts, timeout_ms, want_keepalive, needpriv); 535 } else if (strcmp(options.proxy_command, "-") == 0) { 536 packet_set_connection(STDIN_FILENO, STDOUT_FILENO); 537 return 0; /* Always succeeds */ 538 } else if (options.proxy_use_fdpass) { 539 return ssh_proxy_fdpass_connect(host, port, 540 options.proxy_command); 541 } 542 return ssh_proxy_connect(host, port, options.proxy_command); 543 } 544 545 static void 546 send_client_banner(int connection_out, int minor1) 547 { 548 /* Send our own protocol version identification. */ 549 if (compat20) { 550 xasprintf(&client_version_string, "SSH-%d.%d-%.100s\r\n", 551 PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, SSH_VERSION); 552 } else { 553 xasprintf(&client_version_string, "SSH-%d.%d-%.100s\n", 554 PROTOCOL_MAJOR_1, minor1, SSH_VERSION); 555 } 556 if (roaming_atomicio(vwrite, connection_out, client_version_string, 557 strlen(client_version_string)) != strlen(client_version_string)) 558 fatal("write: %.100s", strerror(errno)); 559 chop(client_version_string); 560 debug("Local version string %.100s", client_version_string); 561 } 562 563 /* 564 * Waits for the server identification string, and sends our own 565 * identification string. 566 */ 567 void 568 ssh_exchange_identification(int timeout_ms) 569 { 570 char buf[256], remote_version[256]; /* must be same size! */ 571 int remote_major, remote_minor, mismatch; 572 int connection_in = packet_get_connection_in(); 573 int connection_out = packet_get_connection_out(); 574 int minor1 = PROTOCOL_MINOR_1, client_banner_sent = 0; 575 u_int i, n; 576 size_t len; 577 int fdsetsz, remaining, rc; 578 struct timeval t_start, t_remaining; 579 fd_set *fdset; 580 581 fdsetsz = howmany(connection_in + 1, NFDBITS) * sizeof(fd_mask); 582 fdset = xcalloc(1, fdsetsz); 583 584 /* 585 * If we are SSH2-only then we can send the banner immediately and 586 * save a round-trip. 587 */ 588 if (options.protocol == SSH_PROTO_2) { 589 enable_compat20(); 590 send_client_banner(connection_out, 0); 591 client_banner_sent = 1; 592 } 593 594 /* Read other side's version identification. */ 595 remaining = timeout_ms; 596 for (n = 0;;) { 597 for (i = 0; i < sizeof(buf) - 1; i++) { 598 if (timeout_ms > 0) { 599 gettimeofday(&t_start, NULL); 600 ms_to_timeval(&t_remaining, remaining); 601 FD_SET(connection_in, fdset); 602 rc = select(connection_in + 1, fdset, NULL, 603 fdset, &t_remaining); 604 ms_subtract_diff(&t_start, &remaining); 605 if (rc == 0 || remaining <= 0) 606 fatal("Connection timed out during " 607 "banner exchange"); 608 if (rc == -1) { 609 if (errno == EINTR) 610 continue; 611 fatal("ssh_exchange_identification: " 612 "select: %s", strerror(errno)); 613 } 614 } 615 616 len = roaming_atomicio(read, connection_in, &buf[i], 1); 617 618 if (len != 1 && errno == EPIPE) 619 fatal("ssh_exchange_identification: " 620 "Connection closed by remote host"); 621 else if (len != 1) 622 fatal("ssh_exchange_identification: " 623 "read: %.100s", strerror(errno)); 624 if (buf[i] == '\r') { 625 buf[i] = '\n'; 626 buf[i + 1] = 0; 627 continue; /**XXX wait for \n */ 628 } 629 if (buf[i] == '\n') { 630 buf[i + 1] = 0; 631 break; 632 } 633 if (++n > 65536) 634 fatal("ssh_exchange_identification: " 635 "No banner received"); 636 } 637 buf[sizeof(buf) - 1] = 0; 638 if (strncmp(buf, "SSH-", 4) == 0) 639 break; 640 debug("ssh_exchange_identification: %s", buf); 641 } 642 server_version_string = xstrdup(buf); 643 free(fdset); 644 645 /* 646 * Check that the versions match. In future this might accept 647 * several versions and set appropriate flags to handle them. 648 */ 649 if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n", 650 &remote_major, &remote_minor, remote_version) != 3) 651 fatal("Bad remote protocol version identification: '%.100s'", buf); 652 debug("Remote protocol version %d.%d, remote software version %.100s", 653 remote_major, remote_minor, remote_version); 654 655 active_state->compat = compat_datafellows(remote_version); 656 mismatch = 0; 657 658 switch (remote_major) { 659 case 1: 660 if (remote_minor == 99 && 661 (options.protocol & SSH_PROTO_2) && 662 !(options.protocol & SSH_PROTO_1_PREFERRED)) { 663 enable_compat20(); 664 break; 665 } 666 if (!(options.protocol & SSH_PROTO_1)) { 667 mismatch = 1; 668 break; 669 } 670 if (remote_minor < 3) { 671 fatal("Remote machine has too old SSH software version."); 672 } else if (remote_minor == 3 || remote_minor == 4) { 673 /* We speak 1.3, too. */ 674 enable_compat13(); 675 minor1 = 3; 676 if (options.forward_agent) { 677 logit("Agent forwarding disabled for protocol 1.3"); 678 options.forward_agent = 0; 679 } 680 } 681 break; 682 case 2: 683 if (options.protocol & SSH_PROTO_2) { 684 enable_compat20(); 685 break; 686 } 687 /* FALLTHROUGH */ 688 default: 689 mismatch = 1; 690 break; 691 } 692 if (mismatch) 693 fatal("Protocol major versions differ: %d vs. %d", 694 (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1, 695 remote_major); 696 if ((datafellows & SSH_BUG_DERIVEKEY) != 0) 697 fatal("Server version \"%.100s\" uses unsafe key agreement; " 698 "refusing connection", remote_version); 699 if ((datafellows & SSH_BUG_RSASIGMD5) != 0) 700 logit("Server version \"%.100s\" uses unsafe RSA signature " 701 "scheme; disabling use of RSA keys", remote_version); 702 if (!client_banner_sent) 703 send_client_banner(connection_out, minor1); 704 chop(server_version_string); 705 } 706 707 708 #if 0 709 /* defaults to 'no' */ 710 static int 711 confirm(const char *prompt) 712 { 713 const char *msg, *again = "Please type 'yes' or 'no': "; 714 char *p; 715 int ret = -1; 716 717 if (options.batch_mode) 718 return 0; 719 for (msg = prompt;;msg = again) { 720 p = read_passphrase(msg, RP_ECHO); 721 if (p == NULL || 722 (p[0] == '\0') || (p[0] == '\n') || 723 strncasecmp(p, "no", 2) == 0) 724 ret = 0; 725 if (p && strncasecmp(p, "yes", 3) == 0) 726 ret = 1; 727 free(p); 728 if (ret != -1) 729 return ret; 730 } 731 } 732 733 static int 734 check_host_cert(const char *host, const Key *host_key) 735 { 736 const char *reason; 737 738 if (key_cert_check_authority(host_key, 1, 0, host, &reason) != 0) { 739 ssh_error("%s", reason); 740 return 0; 741 } 742 if (buffer_len(host_key->cert->critical) != 0) { 743 ssh_error("Certificate for %s contains unsupported " 744 "critical options(s)", host); 745 return 0; 746 } 747 return 1; 748 } 749 750 static int 751 sockaddr_is_local(struct sockaddr *hostaddr) 752 { 753 switch (hostaddr->sa_family) { 754 case AF_INET: 755 return (ntohl(((struct sockaddr_in *)hostaddr)-> 756 sin_addr.s_addr) >> 24) == IN_LOOPBACKNET; 757 case AF_INET6: 758 return IN6_IS_ADDR_LOOPBACK( 759 &(((struct sockaddr_in6 *)hostaddr)->sin6_addr)); 760 default: 761 return 0; 762 } 763 } 764 765 /* 766 * Prepare the hostname and ip address strings that are used to lookup 767 * host keys in known_hosts files. These may have a port number appended. 768 */ 769 void 770 get_hostfile_hostname_ipaddr(char *hostname, struct sockaddr *hostaddr, 771 u_short port, char **hostfile_hostname, char **hostfile_ipaddr) 772 { 773 char ntop[NI_MAXHOST]; 774 socklen_t addrlen; 775 776 switch (hostaddr == NULL ? -1 : hostaddr->sa_family) { 777 case -1: 778 addrlen = 0; 779 break; 780 case AF_INET: 781 addrlen = sizeof(struct sockaddr_in); 782 break; 783 case AF_INET6: 784 addrlen = sizeof(struct sockaddr_in6); 785 break; 786 default: 787 addrlen = sizeof(struct sockaddr); 788 break; 789 } 790 791 /* 792 * We don't have the remote ip-address for connections 793 * using a proxy command 794 */ 795 if (hostfile_ipaddr != NULL) { 796 if (options.proxy_command == NULL) { 797 if (getnameinfo(hostaddr, addrlen, 798 ntop, sizeof(ntop), NULL, 0, NI_NUMERICHOST) != 0) 799 fatal("%s: getnameinfo failed", __func__); 800 *hostfile_ipaddr = put_host_port(ntop, port); 801 } else { 802 *hostfile_ipaddr = xstrdup("<no hostip for proxy " 803 "command>"); 804 } 805 } 806 807 /* 808 * Allow the user to record the key under a different name or 809 * differentiate a non-standard port. This is useful for ssh 810 * tunneling over forwarded connections or if you run multiple 811 * sshd's on different ports on the same machine. 812 */ 813 if (hostfile_hostname != NULL) { 814 if (options.host_key_alias != NULL) { 815 *hostfile_hostname = xstrdup(options.host_key_alias); 816 debug("using hostkeyalias: %s", *hostfile_hostname); 817 } else { 818 *hostfile_hostname = put_host_port(hostname, port); 819 } 820 } 821 } 822 823 /* 824 * check whether the supplied host key is valid, return -1 if the key 825 * is not valid. user_hostfile[0] will not be updated if 'readonly' is true. 826 */ 827 #define RDRW 0 828 #define RDONLY 1 829 #define ROQUIET 2 830 static int 831 check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, 832 Key *host_key, int readonly, 833 char **user_hostfiles, u_int num_user_hostfiles, 834 char **system_hostfiles, u_int num_system_hostfiles) 835 { 836 HostStatus host_status; 837 HostStatus ip_status; 838 Key *raw_key = NULL; 839 char *ip = NULL, *host = NULL; 840 char hostline[1000], *hostp, *fp, *ra; 841 char msg[1024]; 842 const char *type; 843 const struct hostkey_entry *host_found, *ip_found; 844 int len, cancelled_forwarding = 0; 845 int local = sockaddr_is_local(hostaddr); 846 int r, want_cert = key_is_cert(host_key), host_ip_differ = 0; 847 int hostkey_trusted = 0; /* Known or explicitly accepted by user */ 848 struct hostkeys *host_hostkeys, *ip_hostkeys; 849 u_int i; 850 851 /* 852 * Force accepting of the host key for loopback/localhost. The 853 * problem is that if the home directory is NFS-mounted to multiple 854 * machines, localhost will refer to a different machine in each of 855 * them, and the user will get bogus HOST_CHANGED warnings. This 856 * essentially disables host authentication for localhost; however, 857 * this is probably not a real problem. 858 */ 859 if (options.no_host_authentication_for_localhost == 1 && local && 860 options.host_key_alias == NULL) { 861 debug("Forcing accepting of host key for " 862 "loopback/localhost."); 863 return 0; 864 } 865 866 /* 867 * Prepare the hostname and address strings used for hostkey lookup. 868 * In some cases, these will have a port number appended. 869 */ 870 get_hostfile_hostname_ipaddr(hostname, hostaddr, port, &host, &ip); 871 872 /* 873 * Turn off check_host_ip if the connection is to localhost, via proxy 874 * command or if we don't have a hostname to compare with 875 */ 876 if (options.check_host_ip && (local || 877 strcmp(hostname, ip) == 0 || options.proxy_command != NULL)) 878 options.check_host_ip = 0; 879 880 host_hostkeys = init_hostkeys(); 881 for (i = 0; i < num_user_hostfiles; i++) 882 load_hostkeys(host_hostkeys, host, user_hostfiles[i]); 883 for (i = 0; i < num_system_hostfiles; i++) 884 load_hostkeys(host_hostkeys, host, system_hostfiles[i]); 885 886 ip_hostkeys = NULL; 887 if (!want_cert && options.check_host_ip) { 888 ip_hostkeys = init_hostkeys(); 889 for (i = 0; i < num_user_hostfiles; i++) 890 load_hostkeys(ip_hostkeys, ip, user_hostfiles[i]); 891 for (i = 0; i < num_system_hostfiles; i++) 892 load_hostkeys(ip_hostkeys, ip, system_hostfiles[i]); 893 } 894 895 retry: 896 /* Reload these as they may have changed on cert->key downgrade */ 897 want_cert = key_is_cert(host_key); 898 type = key_type(host_key); 899 900 /* 901 * Check if the host key is present in the user's list of known 902 * hosts or in the systemwide list. 903 */ 904 host_status = check_key_in_hostkeys(host_hostkeys, host_key, 905 &host_found); 906 907 /* 908 * Also perform check for the ip address, skip the check if we are 909 * localhost, looking for a certificate, or the hostname was an ip 910 * address to begin with. 911 */ 912 if (!want_cert && ip_hostkeys != NULL) { 913 ip_status = check_key_in_hostkeys(ip_hostkeys, host_key, 914 &ip_found); 915 if (host_status == HOST_CHANGED && 916 (ip_status != HOST_CHANGED || 917 (ip_found != NULL && 918 !key_equal(ip_found->key, host_found->key)))) 919 host_ip_differ = 1; 920 } else 921 ip_status = host_status; 922 923 switch (host_status) { 924 case HOST_OK: 925 /* The host is known and the key matches. */ 926 debug("Host '%.200s' is known and matches the %s host %s.", 927 host, type, want_cert ? "certificate" : "key"); 928 debug("Found %s in %s:%lu", want_cert ? "CA key" : "key", 929 host_found->file, host_found->line); 930 if (want_cert && !check_host_cert(hostname, host_key)) 931 goto fail; 932 if (options.check_host_ip && ip_status == HOST_NEW) { 933 if (readonly || want_cert) 934 logit("%s host key for IP address " 935 "'%.128s' not in list of known hosts.", 936 type, ip); 937 else if (!add_host_to_hostfile(user_hostfiles[0], ip, 938 host_key, options.hash_known_hosts)) 939 logit("Failed to add the %s host key for IP " 940 "address '%.128s' to the list of known " 941 "hosts (%.500s).", type, ip, 942 user_hostfiles[0]); 943 else 944 logit("Warning: Permanently added the %s host " 945 "key for IP address '%.128s' to the list " 946 "of known hosts.", type, ip); 947 } else if (options.visual_host_key) { 948 fp = sshkey_fingerprint(host_key, 949 options.fingerprint_hash, SSH_FP_DEFAULT); 950 ra = sshkey_fingerprint(host_key, 951 options.fingerprint_hash, SSH_FP_RANDOMART); 952 if (fp == NULL || ra == NULL) 953 fatal("%s: sshkey_fingerprint fail", __func__); 954 logit("Host key fingerprint is %s\n%s\n", fp, ra); 955 free(ra); 956 free(fp); 957 } 958 hostkey_trusted = 1; 959 break; 960 case HOST_NEW: 961 if (options.host_key_alias == NULL && port != 0 && 962 port != SSH_DEFAULT_PORT) { 963 debug("checking without port identifier"); 964 if (check_host_key(hostname, hostaddr, 0, host_key, 965 ROQUIET, user_hostfiles, num_user_hostfiles, 966 system_hostfiles, num_system_hostfiles) == 0) { 967 debug("found matching key w/out port"); 968 break; 969 } 970 } 971 if (readonly || want_cert) 972 goto fail; 973 /* The host is new. */ 974 if (options.strict_host_key_checking == 1) { 975 /* 976 * User has requested strict host key checking. We 977 * will not add the host key automatically. The only 978 * alternative left is to abort. 979 */ 980 ssh_error("No %s host key is known for %.200s and you " 981 "have requested strict checking.", type, host); 982 goto fail; 983 } else if (options.strict_host_key_checking == 2) { 984 char msg1[1024], msg2[1024]; 985 986 if (show_other_keys(host_hostkeys, host_key)) 987 snprintf(msg1, sizeof(msg1), 988 "\nbut keys of different type are already" 989 " known for this host."); 990 else 991 snprintf(msg1, sizeof(msg1), "."); 992 /* The default */ 993 fp = sshkey_fingerprint(host_key, 994 options.fingerprint_hash, SSH_FP_DEFAULT); 995 ra = sshkey_fingerprint(host_key, 996 options.fingerprint_hash, SSH_FP_RANDOMART); 997 if (fp == NULL || ra == NULL) 998 fatal("%s: sshkey_fingerprint fail", __func__); 999 msg2[0] = '\0'; 1000 if (options.verify_host_key_dns) { 1001 if (matching_host_key_dns) 1002 snprintf(msg2, sizeof(msg2), 1003 "Matching host key fingerprint" 1004 " found in DNS.\n"); 1005 else 1006 snprintf(msg2, sizeof(msg2), 1007 "No matching host key fingerprint" 1008 " found in DNS.\n"); 1009 } 1010 snprintf(msg, sizeof(msg), 1011 "The authenticity of host '%.200s (%s)' can't be " 1012 "established%s\n" 1013 "%s key fingerprint is %s.%s%s\n%s" 1014 "Are you sure you want to continue connecting " 1015 "(yes/no)? ", 1016 host, ip, msg1, type, fp, 1017 options.visual_host_key ? "\n" : "", 1018 options.visual_host_key ? ra : "", 1019 msg2); 1020 free(ra); 1021 free(fp); 1022 if (!confirm(msg)) 1023 goto fail; 1024 hostkey_trusted = 1; /* user explicitly confirmed */ 1025 } 1026 /* 1027 * If not in strict mode, add the key automatically to the 1028 * local known_hosts file. 1029 */ 1030 if (options.check_host_ip && ip_status == HOST_NEW) { 1031 snprintf(hostline, sizeof(hostline), "%s,%s", host, ip); 1032 hostp = hostline; 1033 if (options.hash_known_hosts) { 1034 /* Add hash of host and IP separately */ 1035 r = add_host_to_hostfile(user_hostfiles[0], 1036 host, host_key, options.hash_known_hosts) && 1037 add_host_to_hostfile(user_hostfiles[0], ip, 1038 host_key, options.hash_known_hosts); 1039 } else { 1040 /* Add unhashed "host,ip" */ 1041 r = add_host_to_hostfile(user_hostfiles[0], 1042 hostline, host_key, 1043 options.hash_known_hosts); 1044 } 1045 } else { 1046 r = add_host_to_hostfile(user_hostfiles[0], host, 1047 host_key, options.hash_known_hosts); 1048 hostp = host; 1049 } 1050 1051 if (!r) 1052 logit("Failed to add the host to the list of known " 1053 "hosts (%.500s).", user_hostfiles[0]); 1054 else 1055 logit("Warning: Permanently added '%.200s' (%s) to the " 1056 "list of known hosts.", hostp, type); 1057 break; 1058 case HOST_REVOKED: 1059 ssh_error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); 1060 ssh_error("@ WARNING: REVOKED HOST KEY DETECTED! @"); 1061 ssh_error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); 1062 ssh_error("The %s host key for %s is marked as revoked.", type, host); 1063 ssh_error("This could mean that a stolen key is being used to"); 1064 ssh_error("impersonate this host."); 1065 1066 /* 1067 * If strict host key checking is in use, the user will have 1068 * to edit the key manually and we can only abort. 1069 */ 1070 if (options.strict_host_key_checking) { 1071 ssh_error("%s host key for %.200s was revoked and you have " 1072 "requested strict checking.", type, host); 1073 goto fail; 1074 } 1075 goto continue_unsafe; 1076 1077 case HOST_CHANGED: 1078 if (want_cert) { 1079 /* 1080 * This is only a debug() since it is valid to have 1081 * CAs with wildcard DNS matches that don't match 1082 * all hosts that one might visit. 1083 */ 1084 debug("Host certificate authority does not " 1085 "match %s in %s:%lu", CA_MARKER, 1086 host_found->file, host_found->line); 1087 goto fail; 1088 } 1089 if (readonly == ROQUIET) 1090 goto fail; 1091 if (options.check_host_ip && host_ip_differ) { 1092 char *key_msg; 1093 if (ip_status == HOST_NEW) 1094 key_msg = "is unknown"; 1095 else if (ip_status == HOST_OK) 1096 key_msg = "is unchanged"; 1097 else 1098 key_msg = "has a different value"; 1099 ssh_error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); 1100 ssh_error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @"); 1101 ssh_error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); 1102 ssh_error("The %s host key for %s has changed,", type, host); 1103 ssh_error("and the key for the corresponding IP address %s", ip); 1104 ssh_error("%s. This could either mean that", key_msg); 1105 ssh_error("DNS SPOOFING is happening or the IP address for the host"); 1106 ssh_error("and its host key have changed at the same time."); 1107 if (ip_status != HOST_NEW) 1108 ssh_error("Offending key for IP in %s:%lu", 1109 ip_found->file, ip_found->line); 1110 } 1111 /* The host key has changed. */ 1112 warn_changed_key(host_key); 1113 ssh_error("Add correct host key in %.100s to get rid of this message.", 1114 user_hostfiles[0]); 1115 ssh_error("Offending %s key in %s:%lu", key_type(host_found->key), 1116 host_found->file, host_found->line); 1117 1118 /* 1119 * If strict host key checking is in use, the user will have 1120 * to edit the key manually and we can only abort. 1121 */ 1122 if (options.strict_host_key_checking) { 1123 ssh_error("%s host key for %.200s has changed and you have " 1124 "requested strict checking.", type, host); 1125 goto fail; 1126 } 1127 1128 continue_unsafe: 1129 /* 1130 * If strict host key checking has not been requested, allow 1131 * the connection but without MITM-able authentication or 1132 * forwarding. 1133 */ 1134 if (options.password_authentication) { 1135 ssh_error("Password authentication is disabled to avoid " 1136 "man-in-the-middle attacks."); 1137 options.password_authentication = 0; 1138 cancelled_forwarding = 1; 1139 } 1140 if (options.kbd_interactive_authentication) { 1141 ssh_error("Keyboard-interactive authentication is disabled" 1142 " to avoid man-in-the-middle attacks."); 1143 options.kbd_interactive_authentication = 0; 1144 options.challenge_response_authentication = 0; 1145 cancelled_forwarding = 1; 1146 } 1147 if (options.challenge_response_authentication) { 1148 ssh_error("Challenge/response authentication is disabled" 1149 " to avoid man-in-the-middle attacks."); 1150 options.challenge_response_authentication = 0; 1151 cancelled_forwarding = 1; 1152 } 1153 if (options.forward_agent) { 1154 ssh_error("Agent forwarding is disabled to avoid " 1155 "man-in-the-middle attacks."); 1156 options.forward_agent = 0; 1157 cancelled_forwarding = 1; 1158 } 1159 if (options.forward_x11) { 1160 ssh_error("X11 forwarding is disabled to avoid " 1161 "man-in-the-middle attacks."); 1162 options.forward_x11 = 0; 1163 cancelled_forwarding = 1; 1164 } 1165 if (options.num_local_forwards > 0 || 1166 options.num_remote_forwards > 0) { 1167 ssh_error("Port forwarding is disabled to avoid " 1168 "man-in-the-middle attacks."); 1169 options.num_local_forwards = 1170 options.num_remote_forwards = 0; 1171 cancelled_forwarding = 1; 1172 } 1173 if (options.tun_open != SSH_TUNMODE_NO) { 1174 ssh_error("Tunnel forwarding is disabled to avoid " 1175 "man-in-the-middle attacks."); 1176 options.tun_open = SSH_TUNMODE_NO; 1177 cancelled_forwarding = 1; 1178 } 1179 if (options.exit_on_forward_failure && cancelled_forwarding) 1180 fatal("Error: forwarding disabled due to host key " 1181 "check failure"); 1182 1183 /* 1184 * XXX Should permit the user to change to use the new id. 1185 * This could be done by converting the host key to an 1186 * identifying sentence, tell that the host identifies itself 1187 * by that sentence, and ask the user if he/she wishes to 1188 * accept the authentication. 1189 */ 1190 break; 1191 case HOST_FOUND: 1192 fatal("internal error"); 1193 break; 1194 } 1195 1196 if (options.check_host_ip && host_status != HOST_CHANGED && 1197 ip_status == HOST_CHANGED) { 1198 snprintf(msg, sizeof(msg), 1199 "Warning: the %s host key for '%.200s' " 1200 "differs from the key for the IP address '%.128s'" 1201 "\nOffending key for IP in %s:%lu", 1202 type, host, ip, ip_found->file, ip_found->line); 1203 if (host_status == HOST_OK) { 1204 len = strlen(msg); 1205 snprintf(msg + len, sizeof(msg) - len, 1206 "\nMatching host key in %s:%lu", 1207 host_found->file, host_found->line); 1208 } 1209 if (options.strict_host_key_checking == 1) { 1210 logit("%s", msg); 1211 ssh_error("Exiting, you have requested strict checking."); 1212 goto fail; 1213 } else if (options.strict_host_key_checking == 2) { 1214 strlcat(msg, "\nAre you sure you want " 1215 "to continue connecting (yes/no)? ", sizeof(msg)); 1216 if (!confirm(msg)) 1217 goto fail; 1218 } else { 1219 logit("%s", msg); 1220 } 1221 } 1222 1223 if (!hostkey_trusted && options.update_hostkeys) { 1224 debug("%s: hostkey not known or explicitly trusted: " 1225 "disabling UpdateHostkeys", __func__); 1226 options.update_hostkeys = 0; 1227 } 1228 1229 free(ip); 1230 free(host); 1231 if (host_hostkeys != NULL) 1232 free_hostkeys(host_hostkeys); 1233 if (ip_hostkeys != NULL) 1234 free_hostkeys(ip_hostkeys); 1235 return 0; 1236 1237 fail: 1238 if (want_cert && host_status != HOST_REVOKED) { 1239 /* 1240 * No matching certificate. Downgrade cert to raw key and 1241 * search normally. 1242 */ 1243 debug("No matching CA found. Retry with plain key"); 1244 raw_key = key_from_private(host_key); 1245 if (key_drop_cert(raw_key) != 0) 1246 fatal("Couldn't drop certificate"); 1247 host_key = raw_key; 1248 goto retry; 1249 } 1250 if (raw_key != NULL) 1251 key_free(raw_key); 1252 free(ip); 1253 free(host); 1254 if (host_hostkeys != NULL) 1255 free_hostkeys(host_hostkeys); 1256 if (ip_hostkeys != NULL) 1257 free_hostkeys(ip_hostkeys); 1258 return -1; 1259 } 1260 1261 /* returns 0 if key verifies or -1 if key does NOT verify */ 1262 int 1263 verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key) 1264 { 1265 int r = -1, flags = 0; 1266 char *fp = NULL; 1267 struct sshkey *plain = NULL; 1268 1269 if ((fp = sshkey_fingerprint(host_key, 1270 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) { 1271 ssh_error("%s: fingerprint host key: %s", __func__, ssh_err(r)); 1272 r = -1; 1273 goto out; 1274 } 1275 1276 debug("Server host key: %s %s", 1277 compat20 ? sshkey_ssh_name(host_key) : sshkey_type(host_key), fp); 1278 1279 if (sshkey_equal(previous_host_key, host_key)) { 1280 debug2("%s: server host key %s %s matches cached key", 1281 __func__, sshkey_type(host_key), fp); 1282 r = 0; 1283 goto out; 1284 } 1285 1286 /* Check in RevokedHostKeys file if specified */ 1287 if (options.revoked_host_keys != NULL) { 1288 r = sshkey_check_revoked(host_key, options.revoked_host_keys); 1289 switch (r) { 1290 case 0: 1291 break; /* not revoked */ 1292 case SSH_ERR_KEY_REVOKED: 1293 ssh_error("Host key %s %s revoked by file %s", 1294 sshkey_type(host_key), fp, 1295 options.revoked_host_keys); 1296 r = -1; 1297 goto out; 1298 default: 1299 ssh_error("Error checking host key %s %s in " 1300 "revoked keys file %s: %s", sshkey_type(host_key), 1301 fp, options.revoked_host_keys, ssh_err(r)); 1302 r = -1; 1303 goto out; 1304 } 1305 } 1306 1307 if (options.verify_host_key_dns) { 1308 /* 1309 * XXX certs are not yet supported for DNS, so downgrade 1310 * them and try the plain key. 1311 */ 1312 if ((r = sshkey_from_private(host_key, &plain)) != 0) 1313 goto out; 1314 if (sshkey_is_cert(plain)) 1315 sshkey_drop_cert(plain); 1316 if (verify_host_key_dns(host, hostaddr, plain, &flags) == 0) { 1317 if (flags & DNS_VERIFY_FOUND) { 1318 if (options.verify_host_key_dns == 1 && 1319 flags & DNS_VERIFY_MATCH && 1320 flags & DNS_VERIFY_SECURE) { 1321 r = 0; 1322 goto out; 1323 } 1324 if (flags & DNS_VERIFY_MATCH) { 1325 matching_host_key_dns = 1; 1326 } else { 1327 warn_changed_key(plain); 1328 ssh_error("Update the SSHFP RR in DNS " 1329 "with the new host key to get rid " 1330 "of this message."); 1331 } 1332 } 1333 } 1334 } 1335 r = check_host_key(host, hostaddr, options.port, host_key, RDRW, 1336 options.user_hostfiles, options.num_user_hostfiles, 1337 options.system_hostfiles, options.num_system_hostfiles); 1338 1339 out: 1340 sshkey_free(plain); 1341 free(fp); 1342 if (r == 0 && host_key != NULL) { 1343 key_free(previous_host_key); 1344 previous_host_key = key_from_private(host_key); 1345 } 1346 1347 return r; 1348 } 1349 1350 /* 1351 * Starts a dialog with the server, and authenticates the current user on the 1352 * server. This does not need any extra privileges. The basic connection 1353 * to the server must already have been established before this is called. 1354 * If login fails, this function prints an error and never returns. 1355 * This function does not require super-user privileges. 1356 */ 1357 void 1358 ssh_login(Sensitive *sensitive, const char *orighost, 1359 struct sockaddr *hostaddr, u_short port, struct passwd *pw, int timeout_ms) 1360 { 1361 char *host; 1362 char *server_user, *local_user; 1363 1364 local_user = xstrdup(pw->pw_name); 1365 server_user = options.user ? options.user : local_user; 1366 1367 /* Convert the user-supplied hostname into all lowercase. */ 1368 host = xstrdup(orighost); 1369 lowercase(host); 1370 1371 /* Exchange protocol version identification strings with the server. */ 1372 ssh_exchange_identification(timeout_ms); 1373 1374 /* Put the connection into non-blocking mode. */ 1375 packet_set_nonblocking(); 1376 1377 /* key exchange */ 1378 /* authenticate user */ 1379 debug("Authenticating to %s:%d as '%s'", host, port, server_user); 1380 if (compat20) { 1381 ssh_kex2(host, hostaddr, port); 1382 ssh_userauth2(local_user, server_user, host, sensitive); 1383 } else { 1384 #ifdef WITH_SSH1 1385 ssh_kex(host, hostaddr); 1386 ssh_userauth1(local_user, server_user, host, sensitive); 1387 #else 1388 fatal("ssh1 is not supported"); 1389 #endif 1390 } 1391 free(local_user); 1392 } 1393 1394 void 1395 ssh_put_password(char *password) 1396 { 1397 int size; 1398 char *padded; 1399 1400 if (datafellows & SSH_BUG_PASSWORDPAD) { 1401 packet_put_cstring(password); 1402 return; 1403 } 1404 size = roundup(strlen(password) + 1, 32); 1405 padded = xcalloc(1, size); 1406 strlcpy(padded, password, size); 1407 packet_put_string(padded, size); 1408 explicit_bzero(padded, size); 1409 free(padded); 1410 } 1411 1412 /* print all known host keys for a given host, but skip keys of given type */ 1413 static int 1414 show_other_keys(struct hostkeys *hostkeys, Key *key) 1415 { 1416 int type[] = { 1417 KEY_RSA1, 1418 KEY_RSA, 1419 KEY_DSA, 1420 KEY_ECDSA, 1421 KEY_ED25519, 1422 -1 1423 }; 1424 int i, ret = 0; 1425 char *fp, *ra; 1426 const struct hostkey_entry *found; 1427 1428 for (i = 0; type[i] != -1; i++) { 1429 if (type[i] == key->type) 1430 continue; 1431 if (!lookup_key_in_hostkeys_by_type(hostkeys, type[i], &found)) 1432 continue; 1433 fp = sshkey_fingerprint(found->key, 1434 options.fingerprint_hash, SSH_FP_DEFAULT); 1435 ra = sshkey_fingerprint(found->key, 1436 options.fingerprint_hash, SSH_FP_RANDOMART); 1437 if (fp == NULL || ra == NULL) 1438 fatal("%s: sshkey_fingerprint fail", __func__); 1439 logit("WARNING: %s key found for host %s\n" 1440 "in %s:%lu\n" 1441 "%s key fingerprint %s.", 1442 key_type(found->key), 1443 found->host, found->file, found->line, 1444 key_type(found->key), fp); 1445 if (options.visual_host_key) 1446 logit("%s", ra); 1447 free(ra); 1448 free(fp); 1449 ret = 1; 1450 } 1451 return ret; 1452 } 1453 1454 static void 1455 warn_changed_key(Key *host_key) 1456 { 1457 char *fp; 1458 1459 fp = sshkey_fingerprint(host_key, options.fingerprint_hash, 1460 SSH_FP_DEFAULT); 1461 if (fp == NULL) 1462 fatal("%s: sshkey_fingerprint fail", __func__); 1463 1464 ssh_error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); 1465 ssh_error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @"); 1466 ssh_error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); 1467 ssh_error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!"); 1468 ssh_error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!"); 1469 ssh_error("It is also possible that a host key has just been changed."); 1470 ssh_error("The fingerprint for the %s key sent by the remote host is\n%s.", 1471 key_type(host_key), fp); 1472 ssh_error("Please contact your system administrator."); 1473 1474 free(fp); 1475 } 1476 1477 /* 1478 * Execute a local command 1479 */ 1480 int 1481 ssh_local_cmd(const char *args) 1482 { 1483 char *shell; 1484 pid_t pid; 1485 int status; 1486 void (*osighand)(int); 1487 1488 if (!options.permit_local_command || 1489 args == NULL || !*args) 1490 return (1); 1491 1492 if ((shell = getenv("SHELL")) == NULL || *shell == '\0') 1493 shell = _PATH_BSHELL; 1494 1495 osighand = signal(SIGCHLD, SIG_DFL); 1496 pid = fork(); 1497 if (pid == 0) { 1498 signal(SIGPIPE, SIG_DFL); 1499 debug3("Executing %s -c \"%s\"", shell, args); 1500 execl(shell, shell, "-c", args, (char *)NULL); 1501 ssh_error("Couldn't execute %s -c \"%s\": %s", 1502 shell, args, strerror(errno)); 1503 _exit(1); 1504 } else if (pid == -1) 1505 fatal("fork failed: %.100s", strerror(errno)); 1506 while (waitpid(pid, &status, 0) == -1) 1507 if (errno != EINTR) 1508 fatal("Couldn't wait for child: %s", strerror(errno)); 1509 signal(SIGCHLD, osighand); 1510 1511 if (!WIFEXITED(status)) 1512 return (1); 1513 1514 return (WEXITSTATUS(status)); 1515 } 1516 1517 #endif 1518 1519 #endif 1520