1 /* $OpenBSD: sshconnect.c,v 1.312 2019/01/24 17:00:29 dtucker 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 <sys/types.h> 17 #include <sys/wait.h> 18 #include <sys/stat.h> 19 #include <sys/socket.h> 20 #include <sys/time.h> 21 22 #include <net/if.h> 23 #include <netinet/in.h> 24 25 #include <ctype.h> 26 #include <errno.h> 27 #include <fcntl.h> 28 #include <netdb.h> 29 #include <paths.h> 30 #include <signal.h> 31 #include <pwd.h> 32 #include <stdio.h> 33 #include <stdlib.h> 34 #include <string.h> 35 #include <unistd.h> 36 #include <ifaddrs.h> 37 38 #include "xmalloc.h" 39 #include "ssh.h" 40 #include "sshbuf.h" 41 #include "packet.h" 42 #include "compat.h" 43 #include "sshkey.h" 44 #include "sshconnect.h" 45 #include "hostfile.h" 46 #include "log.h" 47 #include "misc.h" 48 #include "readconf.h" 49 #include "atomicio.h" 50 #include "dns.h" 51 #include "monitor_fdpass.h" 52 #include "ssh2.h" 53 #include "version.h" 54 #include "authfile.h" 55 #include "ssherr.h" 56 #include "authfd.h" 57 #include "kex.h" 58 59 struct sshkey *previous_host_key = NULL; 60 61 static int matching_host_key_dns = 0; 62 63 static pid_t proxy_command_pid = 0; 64 65 /* import */ 66 extern int debug_flag; 67 extern Options options; 68 extern char *__progname; 69 70 static int show_other_keys(struct hostkeys *, struct sshkey *); 71 static void warn_changed_key(struct sshkey *); 72 73 /* Expand a proxy command */ 74 static char * 75 expand_proxy_command(const char *proxy_command, const char *user, 76 const char *host, int port) 77 { 78 char *tmp, *ret, strport[NI_MAXSERV]; 79 80 snprintf(strport, sizeof strport, "%d", port); 81 xasprintf(&tmp, "exec %s", proxy_command); 82 ret = percent_expand(tmp, "h", host, "p", strport, 83 "r", options.user, (char *)NULL); 84 free(tmp); 85 return ret; 86 } 87 88 static void 89 stderr_null(void) 90 { 91 int devnull; 92 93 if ((devnull = open(_PATH_DEVNULL, O_WRONLY)) == -1) { 94 error("Can't open %s for stderr redirection: %s", 95 _PATH_DEVNULL, strerror(errno)); 96 return; 97 } 98 if (devnull == STDERR_FILENO) 99 return; 100 if (dup2(devnull, STDERR_FILENO) == -1) 101 error("Cannot redirect stderr to %s", _PATH_DEVNULL); 102 if (devnull > STDERR_FILENO) 103 close(devnull); 104 } 105 106 /* 107 * Connect to the given ssh server using a proxy command that passes a 108 * a connected fd back to us. 109 */ 110 static int 111 ssh_proxy_fdpass_connect(struct ssh *ssh, const char *host, u_short port, 112 const char *proxy_command) 113 { 114 char *command_string; 115 int sp[2], sock; 116 pid_t pid; 117 char *shell; 118 119 if ((shell = getenv("SHELL")) == NULL) 120 shell = _PATH_BSHELL; 121 122 if (socketpair(AF_UNIX, SOCK_STREAM, 0, sp) < 0) 123 fatal("Could not create socketpair to communicate with " 124 "proxy dialer: %.100s", strerror(errno)); 125 126 command_string = expand_proxy_command(proxy_command, options.user, 127 host, port); 128 debug("Executing proxy dialer command: %.500s", command_string); 129 130 /* Fork and execute the proxy command. */ 131 if ((pid = fork()) == 0) { 132 char *argv[10]; 133 134 close(sp[1]); 135 /* Redirect stdin and stdout. */ 136 if (sp[0] != 0) { 137 if (dup2(sp[0], 0) < 0) 138 perror("dup2 stdin"); 139 } 140 if (sp[0] != 1) { 141 if (dup2(sp[0], 1) < 0) 142 perror("dup2 stdout"); 143 } 144 if (sp[0] >= 2) 145 close(sp[0]); 146 147 /* 148 * Stderr is left for non-ControlPersist connections is so 149 * error messages may be printed on the user's terminal. 150 */ 151 if (!debug_flag && options.control_path != NULL && 152 options.control_persist) 153 stderr_null(); 154 155 argv[0] = shell; 156 argv[1] = "-c"; 157 argv[2] = command_string; 158 argv[3] = NULL; 159 160 /* 161 * Execute the proxy command. 162 * Note that we gave up any extra privileges above. 163 */ 164 execv(argv[0], argv); 165 perror(argv[0]); 166 exit(1); 167 } 168 /* Parent. */ 169 if (pid < 0) 170 fatal("fork failed: %.100s", strerror(errno)); 171 close(sp[0]); 172 free(command_string); 173 174 if ((sock = mm_receive_fd(sp[1])) == -1) 175 fatal("proxy dialer did not pass back a connection"); 176 close(sp[1]); 177 178 while (waitpid(pid, NULL, 0) == -1) 179 if (errno != EINTR) 180 fatal("Couldn't wait for child: %s", strerror(errno)); 181 182 /* Set the connection file descriptors. */ 183 if (ssh_packet_set_connection(ssh, sock, sock) == NULL) 184 return -1; /* ssh_packet_set_connection logs error */ 185 186 return 0; 187 } 188 189 /* 190 * Connect to the given ssh server using a proxy command. 191 */ 192 static int 193 ssh_proxy_connect(struct ssh *ssh, const char *host, u_short port, 194 const char *proxy_command) 195 { 196 char *command_string; 197 int pin[2], pout[2]; 198 pid_t pid; 199 char *shell; 200 201 if ((shell = getenv("SHELL")) == NULL || *shell == '\0') 202 shell = _PATH_BSHELL; 203 204 /* Create pipes for communicating with the proxy. */ 205 if (pipe(pin) < 0 || pipe(pout) < 0) 206 fatal("Could not create pipes to communicate with the proxy: %.100s", 207 strerror(errno)); 208 209 command_string = expand_proxy_command(proxy_command, options.user, 210 host, port); 211 debug("Executing proxy command: %.500s", command_string); 212 213 /* Fork and execute the proxy command. */ 214 if ((pid = fork()) == 0) { 215 char *argv[10]; 216 217 /* Redirect stdin and stdout. */ 218 close(pin[1]); 219 if (pin[0] != 0) { 220 if (dup2(pin[0], 0) < 0) 221 perror("dup2 stdin"); 222 close(pin[0]); 223 } 224 close(pout[0]); 225 if (dup2(pout[1], 1) < 0) 226 perror("dup2 stdout"); 227 /* Cannot be 1 because pin allocated two descriptors. */ 228 close(pout[1]); 229 230 /* 231 * Stderr is left for non-ControlPersist connections is so 232 * error messages may be printed on the user's terminal. 233 */ 234 if (!debug_flag && options.control_path != NULL && 235 options.control_persist) 236 stderr_null(); 237 238 argv[0] = shell; 239 argv[1] = "-c"; 240 argv[2] = command_string; 241 argv[3] = NULL; 242 243 /* Execute the proxy command. Note that we gave up any 244 extra privileges above. */ 245 signal(SIGPIPE, SIG_DFL); 246 execv(argv[0], argv); 247 perror(argv[0]); 248 exit(1); 249 } 250 /* Parent. */ 251 if (pid < 0) 252 fatal("fork failed: %.100s", strerror(errno)); 253 else 254 proxy_command_pid = pid; /* save pid to clean up later */ 255 256 /* Close child side of the descriptors. */ 257 close(pin[0]); 258 close(pout[1]); 259 260 /* Free the command name. */ 261 free(command_string); 262 263 /* Set the connection file descriptors. */ 264 if (ssh_packet_set_connection(ssh, pout[0], pin[1]) == NULL) 265 return -1; /* ssh_packet_set_connection logs error */ 266 267 return 0; 268 } 269 270 void 271 ssh_kill_proxy_command(void) 272 { 273 /* 274 * Send SIGHUP to proxy command if used. We don't wait() in 275 * case it hangs and instead rely on init to reap the child 276 */ 277 if (proxy_command_pid > 1) 278 kill(proxy_command_pid, SIGHUP); 279 } 280 281 /* 282 * Search a interface address list (returned from getifaddrs(3)) for an 283 * address that matches the desired address family on the specified interface. 284 * Returns 0 and fills in *resultp and *rlenp on success. Returns -1 on failure. 285 */ 286 static int 287 check_ifaddrs(const char *ifname, int af, const struct ifaddrs *ifaddrs, 288 struct sockaddr_storage *resultp, socklen_t *rlenp) 289 { 290 struct sockaddr_in6 *sa6; 291 struct sockaddr_in *sa; 292 struct in6_addr *v6addr; 293 const struct ifaddrs *ifa; 294 int allow_local; 295 296 /* 297 * Prefer addresses that are not loopback or linklocal, but use them 298 * if nothing else matches. 299 */ 300 for (allow_local = 0; allow_local < 2; allow_local++) { 301 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) { 302 if (ifa->ifa_addr == NULL || ifa->ifa_name == NULL || 303 (ifa->ifa_flags & IFF_UP) == 0 || 304 ifa->ifa_addr->sa_family != af || 305 strcmp(ifa->ifa_name, options.bind_interface) != 0) 306 continue; 307 switch (ifa->ifa_addr->sa_family) { 308 case AF_INET: 309 sa = (struct sockaddr_in *)ifa->ifa_addr; 310 if (!allow_local && sa->sin_addr.s_addr == 311 htonl(INADDR_LOOPBACK)) 312 continue; 313 if (*rlenp < sizeof(struct sockaddr_in)) { 314 error("%s: v4 addr doesn't fit", 315 __func__); 316 return -1; 317 } 318 *rlenp = sizeof(struct sockaddr_in); 319 memcpy(resultp, sa, *rlenp); 320 return 0; 321 case AF_INET6: 322 sa6 = (struct sockaddr_in6 *)ifa->ifa_addr; 323 v6addr = &sa6->sin6_addr; 324 if (!allow_local && 325 (IN6_IS_ADDR_LINKLOCAL(v6addr) || 326 IN6_IS_ADDR_LOOPBACK(v6addr))) 327 continue; 328 if (*rlenp < sizeof(struct sockaddr_in6)) { 329 error("%s: v6 addr doesn't fit", 330 __func__); 331 return -1; 332 } 333 *rlenp = sizeof(struct sockaddr_in6); 334 memcpy(resultp, sa6, *rlenp); 335 return 0; 336 } 337 } 338 } 339 return -1; 340 } 341 342 /* 343 * Creates a socket for use as the ssh connection. 344 */ 345 static int 346 ssh_create_socket(struct addrinfo *ai) 347 { 348 int sock, r; 349 struct sockaddr_storage bindaddr; 350 socklen_t bindaddrlen = 0; 351 struct addrinfo hints, *res = NULL; 352 struct ifaddrs *ifaddrs = NULL; 353 char ntop[NI_MAXHOST]; 354 355 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 356 if (sock < 0) { 357 error("socket: %s", strerror(errno)); 358 return -1; 359 } 360 fcntl(sock, F_SETFD, FD_CLOEXEC); 361 362 /* Bind the socket to an alternative local IP address */ 363 if (options.bind_address == NULL && options.bind_interface == NULL) 364 return sock; 365 366 if (options.bind_address != NULL) { 367 memset(&hints, 0, sizeof(hints)); 368 hints.ai_family = ai->ai_family; 369 hints.ai_socktype = ai->ai_socktype; 370 hints.ai_protocol = ai->ai_protocol; 371 hints.ai_flags = AI_PASSIVE; 372 if ((r = getaddrinfo(options.bind_address, NULL, 373 &hints, &res)) != 0) { 374 error("getaddrinfo: %s: %s", options.bind_address, 375 ssh_gai_strerror(r)); 376 goto fail; 377 } 378 if (res == NULL) { 379 error("getaddrinfo: no addrs"); 380 goto fail; 381 } 382 memcpy(&bindaddr, res->ai_addr, res->ai_addrlen); 383 bindaddrlen = res->ai_addrlen; 384 } else if (options.bind_interface != NULL) { 385 if ((r = getifaddrs(&ifaddrs)) != 0) { 386 error("getifaddrs: %s: %s", options.bind_interface, 387 strerror(errno)); 388 goto fail; 389 } 390 bindaddrlen = sizeof(bindaddr); 391 if (check_ifaddrs(options.bind_interface, ai->ai_family, 392 ifaddrs, &bindaddr, &bindaddrlen) != 0) { 393 logit("getifaddrs: %s: no suitable addresses", 394 options.bind_interface); 395 goto fail; 396 } 397 } 398 if ((r = getnameinfo((struct sockaddr *)&bindaddr, bindaddrlen, 399 ntop, sizeof(ntop), NULL, 0, NI_NUMERICHOST)) != 0) { 400 error("%s: getnameinfo failed: %s", __func__, 401 ssh_gai_strerror(r)); 402 goto fail; 403 } 404 if (bind(sock, (struct sockaddr *)&bindaddr, bindaddrlen) != 0) { 405 error("bind %s: %s", ntop, strerror(errno)); 406 goto fail; 407 } 408 debug("%s: bound to %s", __func__, ntop); 409 /* success */ 410 goto out; 411 fail: 412 close(sock); 413 sock = -1; 414 out: 415 if (res != NULL) 416 freeaddrinfo(res); 417 if (ifaddrs != NULL) 418 freeifaddrs(ifaddrs); 419 return sock; 420 } 421 422 /* 423 * Opens a TCP/IP connection to the remote server on the given host. 424 * The address of the remote host will be returned in hostaddr. 425 * If port is 0, the default port will be used. 426 * Connection_attempts specifies the maximum number of tries (one per 427 * second). If proxy_command is non-NULL, it specifies the command (with %h 428 * and %p substituted for host and port, respectively) to use to contact 429 * the daemon. 430 */ 431 static int 432 ssh_connect_direct(struct ssh *ssh, const char *host, struct addrinfo *aitop, 433 struct sockaddr_storage *hostaddr, u_short port, int family, 434 int connection_attempts, int *timeout_ms, int want_keepalive) 435 { 436 int on = 1; 437 int oerrno, sock = -1, attempt; 438 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 439 struct addrinfo *ai; 440 441 debug2("%s", __func__); 442 memset(ntop, 0, sizeof(ntop)); 443 memset(strport, 0, sizeof(strport)); 444 445 for (attempt = 0; attempt < connection_attempts; attempt++) { 446 if (attempt > 0) { 447 /* Sleep a moment before retrying. */ 448 sleep(1); 449 debug("Trying again..."); 450 } 451 /* 452 * Loop through addresses for this host, and try each one in 453 * sequence until the connection succeeds. 454 */ 455 for (ai = aitop; ai; ai = ai->ai_next) { 456 if (ai->ai_family != AF_INET && 457 ai->ai_family != AF_INET6) { 458 errno = EAFNOSUPPORT; 459 continue; 460 } 461 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, 462 ntop, sizeof(ntop), strport, sizeof(strport), 463 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 464 oerrno = errno; 465 error("%s: getnameinfo failed", __func__); 466 errno = oerrno; 467 continue; 468 } 469 debug("Connecting to %.200s [%.100s] port %s.", 470 host, ntop, strport); 471 472 /* Create a socket for connecting. */ 473 sock = ssh_create_socket(ai); 474 if (sock < 0) { 475 /* Any error is already output */ 476 errno = 0; 477 continue; 478 } 479 480 if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen, 481 timeout_ms) >= 0) { 482 /* Successful connection. */ 483 memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen); 484 break; 485 } else { 486 oerrno = errno; 487 debug("connect to address %s port %s: %s", 488 ntop, strport, strerror(errno)); 489 close(sock); 490 sock = -1; 491 errno = oerrno; 492 } 493 } 494 if (sock != -1) 495 break; /* Successful connection. */ 496 } 497 498 /* Return failure if we didn't get a successful connection. */ 499 if (sock == -1) { 500 error("ssh: connect to host %s port %s: %s", 501 host, strport, errno == 0 ? "failure" : strerror(errno)); 502 return -1; 503 } 504 505 debug("Connection established."); 506 507 /* Set SO_KEEPALIVE if requested. */ 508 if (want_keepalive && 509 setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on, 510 sizeof(on)) < 0) 511 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); 512 513 /* Set the connection. */ 514 if (ssh_packet_set_connection(ssh, sock, sock) == NULL) 515 return -1; /* ssh_packet_set_connection logs error */ 516 517 return 0; 518 } 519 520 int 521 ssh_connect(struct ssh *ssh, const char *host, struct addrinfo *addrs, 522 struct sockaddr_storage *hostaddr, u_short port, int family, 523 int connection_attempts, int *timeout_ms, int want_keepalive) 524 { 525 if (options.proxy_command == NULL) { 526 return ssh_connect_direct(ssh, host, addrs, hostaddr, port, 527 family, connection_attempts, timeout_ms, want_keepalive); 528 } else if (strcmp(options.proxy_command, "-") == 0) { 529 if ((ssh_packet_set_connection(ssh, 530 STDIN_FILENO, STDOUT_FILENO)) == NULL) 531 return -1; /* ssh_packet_set_connection logs error */ 532 return 0; 533 } else if (options.proxy_use_fdpass) { 534 return ssh_proxy_fdpass_connect(ssh, host, port, 535 options.proxy_command); 536 } 537 return ssh_proxy_connect(ssh, host, port, options.proxy_command); 538 } 539 540 /* defaults to 'no' */ 541 static int 542 confirm(const char *prompt, const char *fingerprint) 543 { 544 const char *msg, *again = "Please type 'yes' or 'no': "; 545 const char *again_fp = "Please type 'yes', 'no' or the fingerprint: "; 546 char *p; 547 int ret = -1; 548 549 if (options.batch_mode) 550 return 0; 551 for (msg = prompt;;msg = fingerprint ? again_fp : again) { 552 p = read_passphrase(msg, RP_ECHO); 553 if (p == NULL) 554 return 0; 555 p[strcspn(p, "\n")] = '\0'; 556 if (p[0] == '\0' || strcasecmp(p, "no") == 0) 557 ret = 0; 558 else if (strcasecmp(p, "yes") == 0 || (fingerprint != NULL && 559 strcasecmp(p, fingerprint) == 0)) 560 ret = 1; 561 free(p); 562 if (ret != -1) 563 return ret; 564 } 565 } 566 567 static int 568 check_host_cert(const char *host, const struct sshkey *key) 569 { 570 const char *reason; 571 int r; 572 573 if (sshkey_cert_check_authority(key, 1, 0, host, &reason) != 0) { 574 error("%s", reason); 575 return 0; 576 } 577 if (sshbuf_len(key->cert->critical) != 0) { 578 error("Certificate for %s contains unsupported " 579 "critical options(s)", host); 580 return 0; 581 } 582 if ((r = sshkey_check_cert_sigtype(key, 583 options.ca_sign_algorithms)) != 0) { 584 logit("%s: certificate signature algorithm %s: %s", __func__, 585 (key->cert == NULL || key->cert->signature_type == NULL) ? 586 "(null)" : key->cert->signature_type, ssh_err(r)); 587 return 0; 588 } 589 590 return 1; 591 } 592 593 static int 594 sockaddr_is_local(struct sockaddr *hostaddr) 595 { 596 switch (hostaddr->sa_family) { 597 case AF_INET: 598 return (ntohl(((struct sockaddr_in *)hostaddr)-> 599 sin_addr.s_addr) >> 24) == IN_LOOPBACKNET; 600 case AF_INET6: 601 return IN6_IS_ADDR_LOOPBACK( 602 &(((struct sockaddr_in6 *)hostaddr)->sin6_addr)); 603 default: 604 return 0; 605 } 606 } 607 608 /* 609 * Prepare the hostname and ip address strings that are used to lookup 610 * host keys in known_hosts files. These may have a port number appended. 611 */ 612 void 613 get_hostfile_hostname_ipaddr(char *hostname, struct sockaddr *hostaddr, 614 u_short port, char **hostfile_hostname, char **hostfile_ipaddr) 615 { 616 char ntop[NI_MAXHOST]; 617 618 /* 619 * We don't have the remote ip-address for connections 620 * using a proxy command 621 */ 622 if (hostfile_ipaddr != NULL) { 623 if (options.proxy_command == NULL) { 624 if (getnameinfo(hostaddr, hostaddr->sa_len, 625 ntop, sizeof(ntop), NULL, 0, NI_NUMERICHOST) != 0) 626 fatal("%s: getnameinfo failed", __func__); 627 *hostfile_ipaddr = put_host_port(ntop, port); 628 } else { 629 *hostfile_ipaddr = xstrdup("<no hostip for proxy " 630 "command>"); 631 } 632 } 633 634 /* 635 * Allow the user to record the key under a different name or 636 * differentiate a non-standard port. This is useful for ssh 637 * tunneling over forwarded connections or if you run multiple 638 * sshd's on different ports on the same machine. 639 */ 640 if (hostfile_hostname != NULL) { 641 if (options.host_key_alias != NULL) { 642 *hostfile_hostname = xstrdup(options.host_key_alias); 643 debug("using hostkeyalias: %s", *hostfile_hostname); 644 } else { 645 *hostfile_hostname = put_host_port(hostname, port); 646 } 647 } 648 } 649 650 /* 651 * check whether the supplied host key is valid, return -1 if the key 652 * is not valid. user_hostfile[0] will not be updated if 'readonly' is true. 653 */ 654 #define RDRW 0 655 #define RDONLY 1 656 #define ROQUIET 2 657 static int 658 check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, 659 struct sshkey *host_key, int readonly, 660 char **user_hostfiles, u_int num_user_hostfiles, 661 char **system_hostfiles, u_int num_system_hostfiles) 662 { 663 HostStatus host_status; 664 HostStatus ip_status; 665 struct sshkey *raw_key = NULL; 666 char *ip = NULL, *host = NULL; 667 char hostline[1000], *hostp, *fp, *ra; 668 char msg[1024]; 669 const char *type; 670 const struct hostkey_entry *host_found, *ip_found; 671 int len, cancelled_forwarding = 0, confirmed; 672 int local = sockaddr_is_local(hostaddr); 673 int r, want_cert = sshkey_is_cert(host_key), host_ip_differ = 0; 674 int hostkey_trusted = 0; /* Known or explicitly accepted by user */ 675 struct hostkeys *host_hostkeys, *ip_hostkeys; 676 u_int i; 677 678 /* 679 * Force accepting of the host key for loopback/localhost. The 680 * problem is that if the home directory is NFS-mounted to multiple 681 * machines, localhost will refer to a different machine in each of 682 * them, and the user will get bogus HOST_CHANGED warnings. This 683 * essentially disables host authentication for localhost; however, 684 * this is probably not a real problem. 685 */ 686 if (options.no_host_authentication_for_localhost == 1 && local && 687 options.host_key_alias == NULL) { 688 debug("Forcing accepting of host key for " 689 "loopback/localhost."); 690 return 0; 691 } 692 693 /* 694 * Prepare the hostname and address strings used for hostkey lookup. 695 * In some cases, these will have a port number appended. 696 */ 697 get_hostfile_hostname_ipaddr(hostname, hostaddr, port, &host, &ip); 698 699 /* 700 * Turn off check_host_ip if the connection is to localhost, via proxy 701 * command or if we don't have a hostname to compare with 702 */ 703 if (options.check_host_ip && (local || 704 strcmp(hostname, ip) == 0 || options.proxy_command != NULL)) 705 options.check_host_ip = 0; 706 707 host_hostkeys = init_hostkeys(); 708 for (i = 0; i < num_user_hostfiles; i++) 709 load_hostkeys(host_hostkeys, host, user_hostfiles[i]); 710 for (i = 0; i < num_system_hostfiles; i++) 711 load_hostkeys(host_hostkeys, host, system_hostfiles[i]); 712 713 ip_hostkeys = NULL; 714 if (!want_cert && options.check_host_ip) { 715 ip_hostkeys = init_hostkeys(); 716 for (i = 0; i < num_user_hostfiles; i++) 717 load_hostkeys(ip_hostkeys, ip, user_hostfiles[i]); 718 for (i = 0; i < num_system_hostfiles; i++) 719 load_hostkeys(ip_hostkeys, ip, system_hostfiles[i]); 720 } 721 722 retry: 723 /* Reload these as they may have changed on cert->key downgrade */ 724 want_cert = sshkey_is_cert(host_key); 725 type = sshkey_type(host_key); 726 727 /* 728 * Check if the host key is present in the user's list of known 729 * hosts or in the systemwide list. 730 */ 731 host_status = check_key_in_hostkeys(host_hostkeys, host_key, 732 &host_found); 733 734 /* 735 * Also perform check for the ip address, skip the check if we are 736 * localhost, looking for a certificate, or the hostname was an ip 737 * address to begin with. 738 */ 739 if (!want_cert && ip_hostkeys != NULL) { 740 ip_status = check_key_in_hostkeys(ip_hostkeys, host_key, 741 &ip_found); 742 if (host_status == HOST_CHANGED && 743 (ip_status != HOST_CHANGED || 744 (ip_found != NULL && 745 !sshkey_equal(ip_found->key, host_found->key)))) 746 host_ip_differ = 1; 747 } else 748 ip_status = host_status; 749 750 switch (host_status) { 751 case HOST_OK: 752 /* The host is known and the key matches. */ 753 debug("Host '%.200s' is known and matches the %s host %s.", 754 host, type, want_cert ? "certificate" : "key"); 755 debug("Found %s in %s:%lu", want_cert ? "CA key" : "key", 756 host_found->file, host_found->line); 757 if (want_cert && 758 !check_host_cert(options.host_key_alias == NULL ? 759 hostname : options.host_key_alias, host_key)) 760 goto fail; 761 if (options.check_host_ip && ip_status == HOST_NEW) { 762 if (readonly || want_cert) 763 logit("%s host key for IP address " 764 "'%.128s' not in list of known hosts.", 765 type, ip); 766 else if (!add_host_to_hostfile(user_hostfiles[0], ip, 767 host_key, options.hash_known_hosts)) 768 logit("Failed to add the %s host key for IP " 769 "address '%.128s' to the list of known " 770 "hosts (%.500s).", type, ip, 771 user_hostfiles[0]); 772 else 773 logit("Warning: Permanently added the %s host " 774 "key for IP address '%.128s' to the list " 775 "of known hosts.", type, ip); 776 } else if (options.visual_host_key) { 777 fp = sshkey_fingerprint(host_key, 778 options.fingerprint_hash, SSH_FP_DEFAULT); 779 ra = sshkey_fingerprint(host_key, 780 options.fingerprint_hash, SSH_FP_RANDOMART); 781 if (fp == NULL || ra == NULL) 782 fatal("%s: sshkey_fingerprint fail", __func__); 783 logit("Host key fingerprint is %s\n%s", fp, ra); 784 free(ra); 785 free(fp); 786 } 787 hostkey_trusted = 1; 788 break; 789 case HOST_NEW: 790 if (options.host_key_alias == NULL && port != 0 && 791 port != SSH_DEFAULT_PORT) { 792 debug("checking without port identifier"); 793 if (check_host_key(hostname, hostaddr, 0, host_key, 794 ROQUIET, user_hostfiles, num_user_hostfiles, 795 system_hostfiles, num_system_hostfiles) == 0) { 796 debug("found matching key w/out port"); 797 break; 798 } 799 } 800 if (readonly || want_cert) 801 goto fail; 802 /* The host is new. */ 803 if (options.strict_host_key_checking == 804 SSH_STRICT_HOSTKEY_YES) { 805 /* 806 * User has requested strict host key checking. We 807 * will not add the host key automatically. The only 808 * alternative left is to abort. 809 */ 810 error("No %s host key is known for %.200s and you " 811 "have requested strict checking.", type, host); 812 goto fail; 813 } else if (options.strict_host_key_checking == 814 SSH_STRICT_HOSTKEY_ASK) { 815 char msg1[1024], msg2[1024]; 816 817 if (show_other_keys(host_hostkeys, host_key)) 818 snprintf(msg1, sizeof(msg1), 819 "\nbut keys of different type are already" 820 " known for this host."); 821 else 822 snprintf(msg1, sizeof(msg1), "."); 823 /* The default */ 824 fp = sshkey_fingerprint(host_key, 825 options.fingerprint_hash, SSH_FP_DEFAULT); 826 ra = sshkey_fingerprint(host_key, 827 options.fingerprint_hash, SSH_FP_RANDOMART); 828 if (fp == NULL || ra == NULL) 829 fatal("%s: sshkey_fingerprint fail", __func__); 830 msg2[0] = '\0'; 831 if (options.verify_host_key_dns) { 832 if (matching_host_key_dns) 833 snprintf(msg2, sizeof(msg2), 834 "Matching host key fingerprint" 835 " found in DNS.\n"); 836 else 837 snprintf(msg2, sizeof(msg2), 838 "No matching host key fingerprint" 839 " found in DNS.\n"); 840 } 841 snprintf(msg, sizeof(msg), 842 "The authenticity of host '%.200s (%s)' can't be " 843 "established%s\n" 844 "%s key fingerprint is %s.%s%s\n%s" 845 "Are you sure you want to continue connecting " 846 "(yes/no/[fingerprint])? ", 847 host, ip, msg1, type, fp, 848 options.visual_host_key ? "\n" : "", 849 options.visual_host_key ? ra : "", 850 msg2); 851 free(ra); 852 confirmed = confirm(msg, fp); 853 free(fp); 854 if (!confirmed) 855 goto fail; 856 hostkey_trusted = 1; /* user explicitly confirmed */ 857 } 858 /* 859 * If in "new" or "off" strict mode, add the key automatically 860 * to the local known_hosts file. 861 */ 862 if (options.check_host_ip && ip_status == HOST_NEW) { 863 snprintf(hostline, sizeof(hostline), "%s,%s", host, ip); 864 hostp = hostline; 865 if (options.hash_known_hosts) { 866 /* Add hash of host and IP separately */ 867 r = add_host_to_hostfile(user_hostfiles[0], 868 host, host_key, options.hash_known_hosts) && 869 add_host_to_hostfile(user_hostfiles[0], ip, 870 host_key, options.hash_known_hosts); 871 } else { 872 /* Add unhashed "host,ip" */ 873 r = add_host_to_hostfile(user_hostfiles[0], 874 hostline, host_key, 875 options.hash_known_hosts); 876 } 877 } else { 878 r = add_host_to_hostfile(user_hostfiles[0], host, 879 host_key, options.hash_known_hosts); 880 hostp = host; 881 } 882 883 if (!r) 884 logit("Failed to add the host to the list of known " 885 "hosts (%.500s).", user_hostfiles[0]); 886 else 887 logit("Warning: Permanently added '%.200s' (%s) to the " 888 "list of known hosts.", hostp, type); 889 break; 890 case HOST_REVOKED: 891 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); 892 error("@ WARNING: REVOKED HOST KEY DETECTED! @"); 893 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); 894 error("The %s host key for %s is marked as revoked.", type, host); 895 error("This could mean that a stolen key is being used to"); 896 error("impersonate this host."); 897 898 /* 899 * If strict host key checking is in use, the user will have 900 * to edit the key manually and we can only abort. 901 */ 902 if (options.strict_host_key_checking != 903 SSH_STRICT_HOSTKEY_OFF) { 904 error("%s host key for %.200s was revoked and you have " 905 "requested strict checking.", type, host); 906 goto fail; 907 } 908 goto continue_unsafe; 909 910 case HOST_CHANGED: 911 if (want_cert) { 912 /* 913 * This is only a debug() since it is valid to have 914 * CAs with wildcard DNS matches that don't match 915 * all hosts that one might visit. 916 */ 917 debug("Host certificate authority does not " 918 "match %s in %s:%lu", CA_MARKER, 919 host_found->file, host_found->line); 920 goto fail; 921 } 922 if (readonly == ROQUIET) 923 goto fail; 924 if (options.check_host_ip && host_ip_differ) { 925 char *key_msg; 926 if (ip_status == HOST_NEW) 927 key_msg = "is unknown"; 928 else if (ip_status == HOST_OK) 929 key_msg = "is unchanged"; 930 else 931 key_msg = "has a different value"; 932 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); 933 error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @"); 934 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); 935 error("The %s host key for %s has changed,", type, host); 936 error("and the key for the corresponding IP address %s", ip); 937 error("%s. This could either mean that", key_msg); 938 error("DNS SPOOFING is happening or the IP address for the host"); 939 error("and its host key have changed at the same time."); 940 if (ip_status != HOST_NEW) 941 error("Offending key for IP in %s:%lu", 942 ip_found->file, ip_found->line); 943 } 944 /* The host key has changed. */ 945 warn_changed_key(host_key); 946 error("Add correct host key in %.100s to get rid of this message.", 947 user_hostfiles[0]); 948 error("Offending %s key in %s:%lu", 949 sshkey_type(host_found->key), 950 host_found->file, host_found->line); 951 952 /* 953 * If strict host key checking is in use, the user will have 954 * to edit the key manually and we can only abort. 955 */ 956 if (options.strict_host_key_checking != 957 SSH_STRICT_HOSTKEY_OFF) { 958 error("%s host key for %.200s has changed and you have " 959 "requested strict checking.", type, host); 960 goto fail; 961 } 962 963 continue_unsafe: 964 /* 965 * If strict host key checking has not been requested, allow 966 * the connection but without MITM-able authentication or 967 * forwarding. 968 */ 969 if (options.password_authentication) { 970 error("Password authentication is disabled to avoid " 971 "man-in-the-middle attacks."); 972 options.password_authentication = 0; 973 cancelled_forwarding = 1; 974 } 975 if (options.kbd_interactive_authentication) { 976 error("Keyboard-interactive authentication is disabled" 977 " to avoid man-in-the-middle attacks."); 978 options.kbd_interactive_authentication = 0; 979 options.challenge_response_authentication = 0; 980 cancelled_forwarding = 1; 981 } 982 if (options.challenge_response_authentication) { 983 error("Challenge/response authentication is disabled" 984 " to avoid man-in-the-middle attacks."); 985 options.challenge_response_authentication = 0; 986 cancelled_forwarding = 1; 987 } 988 if (options.forward_agent) { 989 error("Agent forwarding is disabled to avoid " 990 "man-in-the-middle attacks."); 991 options.forward_agent = 0; 992 cancelled_forwarding = 1; 993 } 994 if (options.forward_x11) { 995 error("X11 forwarding is disabled to avoid " 996 "man-in-the-middle attacks."); 997 options.forward_x11 = 0; 998 cancelled_forwarding = 1; 999 } 1000 if (options.num_local_forwards > 0 || 1001 options.num_remote_forwards > 0) { 1002 error("Port forwarding is disabled to avoid " 1003 "man-in-the-middle attacks."); 1004 options.num_local_forwards = 1005 options.num_remote_forwards = 0; 1006 cancelled_forwarding = 1; 1007 } 1008 if (options.tun_open != SSH_TUNMODE_NO) { 1009 error("Tunnel forwarding is disabled to avoid " 1010 "man-in-the-middle attacks."); 1011 options.tun_open = SSH_TUNMODE_NO; 1012 cancelled_forwarding = 1; 1013 } 1014 if (options.exit_on_forward_failure && cancelled_forwarding) 1015 fatal("Error: forwarding disabled due to host key " 1016 "check failure"); 1017 1018 /* 1019 * XXX Should permit the user to change to use the new id. 1020 * This could be done by converting the host key to an 1021 * identifying sentence, tell that the host identifies itself 1022 * by that sentence, and ask the user if he/she wishes to 1023 * accept the authentication. 1024 */ 1025 break; 1026 case HOST_FOUND: 1027 fatal("internal error"); 1028 break; 1029 } 1030 1031 if (options.check_host_ip && host_status != HOST_CHANGED && 1032 ip_status == HOST_CHANGED) { 1033 snprintf(msg, sizeof(msg), 1034 "Warning: the %s host key for '%.200s' " 1035 "differs from the key for the IP address '%.128s'" 1036 "\nOffending key for IP in %s:%lu", 1037 type, host, ip, ip_found->file, ip_found->line); 1038 if (host_status == HOST_OK) { 1039 len = strlen(msg); 1040 snprintf(msg + len, sizeof(msg) - len, 1041 "\nMatching host key in %s:%lu", 1042 host_found->file, host_found->line); 1043 } 1044 if (options.strict_host_key_checking == 1045 SSH_STRICT_HOSTKEY_ASK) { 1046 strlcat(msg, "\nAre you sure you want " 1047 "to continue connecting (yes/no)? ", sizeof(msg)); 1048 if (!confirm(msg, NULL)) 1049 goto fail; 1050 } else if (options.strict_host_key_checking != 1051 SSH_STRICT_HOSTKEY_OFF) { 1052 logit("%s", msg); 1053 error("Exiting, you have requested strict checking."); 1054 goto fail; 1055 } else { 1056 logit("%s", msg); 1057 } 1058 } 1059 1060 if (!hostkey_trusted && options.update_hostkeys) { 1061 debug("%s: hostkey not known or explicitly trusted: " 1062 "disabling UpdateHostkeys", __func__); 1063 options.update_hostkeys = 0; 1064 } 1065 1066 free(ip); 1067 free(host); 1068 if (host_hostkeys != NULL) 1069 free_hostkeys(host_hostkeys); 1070 if (ip_hostkeys != NULL) 1071 free_hostkeys(ip_hostkeys); 1072 return 0; 1073 1074 fail: 1075 if (want_cert && host_status != HOST_REVOKED) { 1076 /* 1077 * No matching certificate. Downgrade cert to raw key and 1078 * search normally. 1079 */ 1080 debug("No matching CA found. Retry with plain key"); 1081 if ((r = sshkey_from_private(host_key, &raw_key)) != 0) 1082 fatal("%s: sshkey_from_private: %s", 1083 __func__, ssh_err(r)); 1084 if ((r = sshkey_drop_cert(raw_key)) != 0) 1085 fatal("Couldn't drop certificate: %s", ssh_err(r)); 1086 host_key = raw_key; 1087 goto retry; 1088 } 1089 sshkey_free(raw_key); 1090 free(ip); 1091 free(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, struct sshkey *host_key) 1102 { 1103 u_int i; 1104 int r = -1, flags = 0; 1105 char valid[64], *fp = NULL, *cafp = NULL; 1106 struct sshkey *plain = NULL; 1107 1108 if ((fp = sshkey_fingerprint(host_key, 1109 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) { 1110 error("%s: fingerprint host key: %s", __func__, ssh_err(r)); 1111 r = -1; 1112 goto out; 1113 } 1114 1115 if (sshkey_is_cert(host_key)) { 1116 if ((cafp = sshkey_fingerprint(host_key->cert->signature_key, 1117 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) { 1118 error("%s: fingerprint CA key: %s", 1119 __func__, ssh_err(r)); 1120 r = -1; 1121 goto out; 1122 } 1123 sshkey_format_cert_validity(host_key->cert, 1124 valid, sizeof(valid)); 1125 debug("Server host certificate: %s %s, serial %llu " 1126 "ID \"%s\" CA %s %s valid %s", 1127 sshkey_ssh_name(host_key), fp, 1128 (unsigned long long)host_key->cert->serial, 1129 host_key->cert->key_id, 1130 sshkey_ssh_name(host_key->cert->signature_key), cafp, 1131 valid); 1132 for (i = 0; i < host_key->cert->nprincipals; i++) { 1133 debug2("Server host certificate hostname: %s", 1134 host_key->cert->principals[i]); 1135 } 1136 } else { 1137 debug("Server host key: %s %s", sshkey_ssh_name(host_key), fp); 1138 } 1139 1140 if (sshkey_equal(previous_host_key, host_key)) { 1141 debug2("%s: server host key %s %s matches cached key", 1142 __func__, sshkey_type(host_key), fp); 1143 r = 0; 1144 goto out; 1145 } 1146 1147 /* Check in RevokedHostKeys file if specified */ 1148 if (options.revoked_host_keys != NULL) { 1149 r = sshkey_check_revoked(host_key, options.revoked_host_keys); 1150 switch (r) { 1151 case 0: 1152 break; /* not revoked */ 1153 case SSH_ERR_KEY_REVOKED: 1154 error("Host key %s %s revoked by file %s", 1155 sshkey_type(host_key), fp, 1156 options.revoked_host_keys); 1157 r = -1; 1158 goto out; 1159 default: 1160 error("Error checking host key %s %s in " 1161 "revoked keys file %s: %s", sshkey_type(host_key), 1162 fp, options.revoked_host_keys, ssh_err(r)); 1163 r = -1; 1164 goto out; 1165 } 1166 } 1167 1168 if (options.verify_host_key_dns) { 1169 /* 1170 * XXX certs are not yet supported for DNS, so downgrade 1171 * them and try the plain key. 1172 */ 1173 if ((r = sshkey_from_private(host_key, &plain)) != 0) 1174 goto out; 1175 if (sshkey_is_cert(plain)) 1176 sshkey_drop_cert(plain); 1177 if (verify_host_key_dns(host, hostaddr, plain, &flags) == 0) { 1178 if (flags & DNS_VERIFY_FOUND) { 1179 if (options.verify_host_key_dns == 1 && 1180 flags & DNS_VERIFY_MATCH && 1181 flags & DNS_VERIFY_SECURE) { 1182 r = 0; 1183 goto out; 1184 } 1185 if (flags & DNS_VERIFY_MATCH) { 1186 matching_host_key_dns = 1; 1187 } else { 1188 warn_changed_key(plain); 1189 error("Update the SSHFP RR in DNS " 1190 "with the new host key to get rid " 1191 "of this message."); 1192 } 1193 } 1194 } 1195 } 1196 r = check_host_key(host, hostaddr, options.port, host_key, RDRW, 1197 options.user_hostfiles, options.num_user_hostfiles, 1198 options.system_hostfiles, options.num_system_hostfiles); 1199 1200 out: 1201 sshkey_free(plain); 1202 free(fp); 1203 free(cafp); 1204 if (r == 0 && host_key != NULL) { 1205 sshkey_free(previous_host_key); 1206 r = sshkey_from_private(host_key, &previous_host_key); 1207 } 1208 1209 return r; 1210 } 1211 1212 /* 1213 * Starts a dialog with the server, and authenticates the current user on the 1214 * server. This does not need any extra privileges. The basic connection 1215 * to the server must already have been established before this is called. 1216 * If login fails, this function prints an error and never returns. 1217 * This function does not require super-user privileges. 1218 */ 1219 void 1220 ssh_login(struct ssh *ssh, Sensitive *sensitive, const char *orighost, 1221 struct sockaddr *hostaddr, u_short port, struct passwd *pw, int timeout_ms) 1222 { 1223 char *host; 1224 char *server_user, *local_user; 1225 1226 local_user = xstrdup(pw->pw_name); 1227 server_user = options.user ? options.user : local_user; 1228 1229 /* Convert the user-supplied hostname into all lowercase. */ 1230 host = xstrdup(orighost); 1231 lowercase(host); 1232 1233 /* Exchange protocol version identification strings with the server. */ 1234 if (kex_exchange_identification(ssh, timeout_ms, NULL) != 0) 1235 cleanup_exit(255); /* error already logged */ 1236 1237 /* Put the connection into non-blocking mode. */ 1238 ssh_packet_set_nonblocking(ssh); 1239 1240 /* key exchange */ 1241 /* authenticate user */ 1242 debug("Authenticating to %s:%d as '%s'", host, port, server_user); 1243 ssh_kex2(ssh, host, hostaddr, port); 1244 ssh_userauth2(ssh, local_user, server_user, host, sensitive); 1245 free(local_user); 1246 } 1247 1248 /* print all known host keys for a given host, but skip keys of given type */ 1249 static int 1250 show_other_keys(struct hostkeys *hostkeys, struct sshkey *key) 1251 { 1252 int type[] = { 1253 KEY_RSA, 1254 KEY_DSA, 1255 KEY_ECDSA, 1256 KEY_ED25519, 1257 KEY_XMSS, 1258 -1 1259 }; 1260 int i, ret = 0; 1261 char *fp, *ra; 1262 const struct hostkey_entry *found; 1263 1264 for (i = 0; type[i] != -1; i++) { 1265 if (type[i] == key->type) 1266 continue; 1267 if (!lookup_key_in_hostkeys_by_type(hostkeys, type[i], &found)) 1268 continue; 1269 fp = sshkey_fingerprint(found->key, 1270 options.fingerprint_hash, SSH_FP_DEFAULT); 1271 ra = sshkey_fingerprint(found->key, 1272 options.fingerprint_hash, SSH_FP_RANDOMART); 1273 if (fp == NULL || ra == NULL) 1274 fatal("%s: sshkey_fingerprint fail", __func__); 1275 logit("WARNING: %s key found for host %s\n" 1276 "in %s:%lu\n" 1277 "%s key fingerprint %s.", 1278 sshkey_type(found->key), 1279 found->host, found->file, found->line, 1280 sshkey_type(found->key), fp); 1281 if (options.visual_host_key) 1282 logit("%s", ra); 1283 free(ra); 1284 free(fp); 1285 ret = 1; 1286 } 1287 return ret; 1288 } 1289 1290 static void 1291 warn_changed_key(struct sshkey *host_key) 1292 { 1293 char *fp; 1294 1295 fp = sshkey_fingerprint(host_key, options.fingerprint_hash, 1296 SSH_FP_DEFAULT); 1297 if (fp == NULL) 1298 fatal("%s: sshkey_fingerprint fail", __func__); 1299 1300 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); 1301 error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @"); 1302 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); 1303 error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!"); 1304 error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!"); 1305 error("It is also possible that a host key has just been changed."); 1306 error("The fingerprint for the %s key sent by the remote host is\n%s.", 1307 sshkey_type(host_key), fp); 1308 error("Please contact your system administrator."); 1309 1310 free(fp); 1311 } 1312 1313 /* 1314 * Execute a local command 1315 */ 1316 int 1317 ssh_local_cmd(const char *args) 1318 { 1319 char *shell; 1320 pid_t pid; 1321 int status; 1322 void (*osighand)(int); 1323 1324 if (!options.permit_local_command || 1325 args == NULL || !*args) 1326 return (1); 1327 1328 if ((shell = getenv("SHELL")) == NULL || *shell == '\0') 1329 shell = _PATH_BSHELL; 1330 1331 osighand = signal(SIGCHLD, SIG_DFL); 1332 pid = fork(); 1333 if (pid == 0) { 1334 signal(SIGPIPE, SIG_DFL); 1335 debug3("Executing %s -c \"%s\"", shell, args); 1336 execl(shell, shell, "-c", args, (char *)NULL); 1337 error("Couldn't execute %s -c \"%s\": %s", 1338 shell, args, strerror(errno)); 1339 _exit(1); 1340 } else if (pid == -1) 1341 fatal("fork failed: %.100s", strerror(errno)); 1342 while (waitpid(pid, &status, 0) == -1) 1343 if (errno != EINTR) 1344 fatal("Couldn't wait for child: %s", strerror(errno)); 1345 signal(SIGCHLD, osighand); 1346 1347 if (!WIFEXITED(status)) 1348 return (1); 1349 1350 return (WEXITSTATUS(status)); 1351 } 1352 1353 void 1354 maybe_add_key_to_agent(char *authfile, const struct sshkey *private, 1355 char *comment, char *passphrase) 1356 { 1357 int auth_sock = -1, r; 1358 1359 if (options.add_keys_to_agent == 0) 1360 return; 1361 1362 if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) { 1363 debug3("no authentication agent, not adding key"); 1364 return; 1365 } 1366 1367 if (options.add_keys_to_agent == 2 && 1368 !ask_permission("Add key %s (%s) to agent?", authfile, comment)) { 1369 debug3("user denied adding this key"); 1370 close(auth_sock); 1371 return; 1372 } 1373 1374 if ((r = ssh_add_identity_constrained(auth_sock, private, comment, 0, 1375 (options.add_keys_to_agent == 3), 0)) == 0) 1376 debug("identity added to agent: %s", authfile); 1377 else 1378 debug("could not add identity to agent: %s (%d)", authfile, r); 1379 close(auth_sock); 1380 } 1381