Annotation of src/usr.bin/ssh/sshconnect.c, Revision 1.215
1.215 ! reyk 1: /* $OpenBSD: sshconnect.c,v 1.214 2009/05/28 16:50:16 andreas Exp $ */
1.1 deraadt 2: /*
1.39 deraadt 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.
1.78 deraadt 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".
1.39 deraadt 14: */
1.1 deraadt 15:
1.174 stevesk 16: #include <sys/types.h>
17: #include <sys/wait.h>
1.175 stevesk 18: #include <sys/stat.h>
1.187 stevesk 19: #include <sys/socket.h>
1.195 stevesk 20: #include <sys/time.h>
1.187 stevesk 21:
22: #include <netinet/in.h>
1.172 stevesk 23:
1.176 stevesk 24: #include <ctype.h>
1.190 stevesk 25: #include <errno.h>
1.191 stevesk 26: #include <netdb.h>
1.172 stevesk 27: #include <paths.h>
1.199 deraadt 28: #include <signal.h>
1.188 stevesk 29: #include <pwd.h>
1.198 stevesk 30: #include <stdio.h>
1.196 stevesk 31: #include <stdlib.h>
1.193 stevesk 32: #include <string.h>
1.192 stevesk 33: #include <unistd.h>
1.71 markus 34:
1.199 deraadt 35: #include "xmalloc.h"
1.91 markus 36: #include "ssh.h"
1.1 deraadt 37: #include "rsa.h"
1.59 markus 38: #include "buffer.h"
1.1 deraadt 39: #include "packet.h"
40: #include "uidswap.h"
1.21 markus 41: #include "compat.h"
1.58 markus 42: #include "key.h"
1.71 markus 43: #include "sshconnect.h"
1.58 markus 44: #include "hostfile.h"
1.91 markus 45: #include "log.h"
46: #include "readconf.h"
47: #include "atomicio.h"
48: #include "misc.h"
1.140 jakob 49: #include "dns.h"
1.214 andreas 50: #include "roaming.h"
1.186 stevesk 51: #include "version.h"
1.140 jakob 52:
1.70 markus 53: char *client_version_string = NULL;
54: char *server_version_string = NULL;
1.59 markus 55:
1.169 stevesk 56: static int matching_host_key_dns = 0;
1.145 jakob 57:
1.124 markus 58: /* import */
1.43 markus 59: extern Options options;
1.50 markus 60: extern char *__progname;
1.124 markus 61: extern uid_t original_real_uid;
62: extern uid_t original_effective_uid;
1.135 djm 63: extern pid_t proxy_command_pid;
1.91 markus 64:
1.132 markus 65: static int show_other_keys(const char *, Key *);
1.150 jakob 66: static void warn_changed_key(Key *);
1.132 markus 67:
1.39 deraadt 68: /*
69: * Connect to the given ssh server using a proxy command.
70: */
1.109 itojun 71: static int
1.124 markus 72: ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
1.1 deraadt 73: {
1.164 djm 74: char *command_string, *tmp;
1.38 markus 75: int pin[2], pout[2];
1.69 deraadt 76: pid_t pid;
1.201 djm 77: char *shell, strport[NI_MAXSERV];
78:
79: if ((shell = getenv("SHELL")) == NULL)
80: shell = _PATH_BSHELL;
1.38 markus 81:
82: /* Convert the port number into a string. */
1.49 markus 83: snprintf(strport, sizeof strport, "%hu", port);
1.38 markus 84:
1.135 djm 85: /*
86: * Build the final command string in the buffer by making the
87: * appropriate substitutions to the given proxy command.
88: *
1.154 djm 89: * Use "exec" to avoid "sh -c" processes on some platforms
1.135 djm 90: * (e.g. Solaris)
91: */
1.179 djm 92: xasprintf(&tmp, "exec %s", proxy_command);
1.164 djm 93: command_string = percent_expand(tmp, "h", host,
94: "p", strport, (char *)NULL);
95: xfree(tmp);
1.38 markus 96:
97: /* Create pipes for communicating with the proxy. */
98: if (pipe(pin) < 0 || pipe(pout) < 0)
99: fatal("Could not create pipes to communicate with the proxy: %.100s",
1.118 deraadt 100: strerror(errno));
1.38 markus 101:
102: debug("Executing proxy command: %.500s", command_string);
103:
104: /* Fork and execute the proxy command. */
105: if ((pid = fork()) == 0) {
106: char *argv[10];
107:
108: /* Child. Permanently give up superuser privileges. */
1.184 markus 109: permanently_drop_suid(original_real_uid);
1.38 markus 110:
111: /* Redirect stdin and stdout. */
112: close(pin[1]);
113: if (pin[0] != 0) {
114: if (dup2(pin[0], 0) < 0)
115: perror("dup2 stdin");
116: close(pin[0]);
117: }
118: close(pout[0]);
119: if (dup2(pout[1], 1) < 0)
120: perror("dup2 stdout");
121: /* Cannot be 1 because pin allocated two descriptors. */
122: close(pout[1]);
123:
124: /* Stderr is left as it is so that error messages get
125: printed on the user's terminal. */
1.201 djm 126: argv[0] = shell;
1.38 markus 127: argv[1] = "-c";
128: argv[2] = command_string;
129: argv[3] = NULL;
130:
131: /* Execute the proxy command. Note that we gave up any
132: extra privileges above. */
1.89 markus 133: execv(argv[0], argv);
134: perror(argv[0]);
1.38 markus 135: exit(1);
136: }
137: /* Parent. */
138: if (pid < 0)
139: fatal("fork failed: %.100s", strerror(errno));
1.135 djm 140: else
141: proxy_command_pid = pid; /* save pid to clean up later */
1.38 markus 142:
143: /* Close child side of the descriptors. */
144: close(pin[0]);
145: close(pout[1]);
146:
147: /* Free the command name. */
1.164 djm 148: xfree(command_string);
1.38 markus 149:
150: /* Set the connection file descriptors. */
151: packet_set_connection(pout[0], pin[1]);
1.207 dtucker 152: packet_set_timeout(options.server_alive_interval,
153: options.server_alive_count_max);
1.1 deraadt 154:
1.110 markus 155: /* Indicate OK return */
156: return 0;
1.1 deraadt 157: }
158:
1.39 deraadt 159: /*
160: * Creates a (possibly privileged) socket for use as the ssh connection.
161: */
1.109 itojun 162: static int
1.139 markus 163: ssh_create_socket(int privileged, struct addrinfo *ai)
1.1 deraadt 164: {
1.105 markus 165: int sock, gaierr;
166: struct addrinfo hints, *res;
1.1 deraadt 167:
1.40 markus 168: /*
169: * If we are running as root and want to connect to a privileged
170: * port, bind our own socket to a privileged port.
171: */
1.38 markus 172: if (privileged) {
173: int p = IPPORT_RESERVED - 1;
1.124 markus 174: PRIV_START;
1.139 markus 175: sock = rresvport_af(&p, ai->ai_family);
1.124 markus 176: PRIV_END;
1.38 markus 177: if (sock < 0)
1.139 markus 178: error("rresvport: af=%d %.100s", ai->ai_family,
179: strerror(errno));
1.55 markus 180: else
181: debug("Allocated local port %d.", p);
1.105 markus 182: return sock;
183: }
1.215 ! reyk 184: sock = socket_rdomain(ai->ai_family, ai->ai_socktype, ai->ai_protocol,
! 185: options.rdomain);
1.105 markus 186: if (sock < 0)
187: error("socket: %.100s", strerror(errno));
188:
189: /* Bind the socket to an alternative local IP address */
190: if (options.bind_address == NULL)
191: return sock;
192:
193: memset(&hints, 0, sizeof(hints));
1.139 markus 194: hints.ai_family = ai->ai_family;
195: hints.ai_socktype = ai->ai_socktype;
196: hints.ai_protocol = ai->ai_protocol;
1.105 markus 197: hints.ai_flags = AI_PASSIVE;
1.205 dtucker 198: gaierr = getaddrinfo(options.bind_address, NULL, &hints, &res);
1.105 markus 199: if (gaierr) {
200: error("getaddrinfo: %s: %s", options.bind_address,
1.203 dtucker 201: ssh_gai_strerror(gaierr));
1.105 markus 202: close(sock);
203: return -1;
204: }
205: if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
206: error("bind: %s: %s", options.bind_address, strerror(errno));
207: close(sock);
208: freeaddrinfo(res);
209: return -1;
1.38 markus 210: }
1.105 markus 211: freeaddrinfo(res);
1.38 markus 212: return sock;
1.1 deraadt 213: }
214:
1.141 djm 215: static int
216: timeout_connect(int sockfd, const struct sockaddr *serv_addr,
1.202 djm 217: socklen_t addrlen, int *timeoutp)
1.141 djm 218: {
219: fd_set *fdset;
1.202 djm 220: struct timeval tv, t_start;
1.141 djm 221: socklen_t optlen;
1.179 djm 222: int optval, rc, result = -1;
1.141 djm 223:
1.202 djm 224: gettimeofday(&t_start, NULL);
225:
226: if (*timeoutp <= 0) {
227: result = connect(sockfd, serv_addr, addrlen);
228: goto done;
229: }
1.141 djm 230:
1.156 djm 231: set_nonblock(sockfd);
1.141 djm 232: rc = connect(sockfd, serv_addr, addrlen);
1.156 djm 233: if (rc == 0) {
234: unset_nonblock(sockfd);
1.202 djm 235: result = 0;
236: goto done;
237: }
238: if (errno != EINPROGRESS) {
239: result = -1;
240: goto done;
1.156 djm 241: }
1.141 djm 242:
1.179 djm 243: fdset = (fd_set *)xcalloc(howmany(sockfd + 1, NFDBITS),
244: sizeof(fd_mask));
1.141 djm 245: FD_SET(sockfd, fdset);
1.202 djm 246: ms_to_timeval(&tv, *timeoutp);
1.141 djm 247:
1.162 deraadt 248: for (;;) {
1.141 djm 249: rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
250: if (rc != -1 || errno != EINTR)
251: break;
252: }
253:
1.162 deraadt 254: switch (rc) {
1.141 djm 255: case 0:
256: /* Timed out */
257: errno = ETIMEDOUT;
1.142 djm 258: break;
1.141 djm 259: case -1:
260: /* Select error */
1.154 djm 261: debug("select: %s", strerror(errno));
1.142 djm 262: break;
1.141 djm 263: case 1:
264: /* Completed or failed */
265: optval = 0;
266: optlen = sizeof(optval);
1.154 djm 267: if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval,
1.148 markus 268: &optlen) == -1) {
1.154 djm 269: debug("getsockopt: %s", strerror(errno));
1.142 djm 270: break;
1.148 markus 271: }
1.141 djm 272: if (optval != 0) {
273: errno = optval;
1.142 djm 274: break;
1.141 djm 275: }
1.142 djm 276: result = 0;
1.156 djm 277: unset_nonblock(sockfd);
1.141 djm 278: break;
279: default:
280: /* Should not occur */
281: fatal("Bogus return (%d) from select()", rc);
282: }
283:
1.142 djm 284: xfree(fdset);
1.202 djm 285:
286: done:
287: if (result == 0 && *timeoutp > 0) {
288: ms_subtract_diff(&t_start, timeoutp);
289: if (*timeoutp <= 0) {
290: errno = ETIMEDOUT;
291: result = -1;
292: }
293: }
294:
1.142 djm 295: return (result);
1.141 djm 296: }
297:
1.39 deraadt 298: /*
1.49 markus 299: * Opens a TCP/IP connection to the remote server on the given host.
300: * The address of the remote host will be returned in hostaddr.
1.124 markus 301: * If port is 0, the default port will be used. If needpriv is true,
1.39 deraadt 302: * a privileged port will be allocated to make the connection.
1.124 markus 303: * This requires super-user privileges if needpriv is true.
1.39 deraadt 304: * Connection_attempts specifies the maximum number of tries (one per
305: * second). If proxy_command is non-NULL, it specifies the command (with %h
306: * and %p substituted for host and port, respectively) to use to contact
307: * the daemon.
308: */
1.38 markus 309: int
1.49 markus 310: ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
1.202 djm 311: u_short port, int family, int connection_attempts, int *timeout_ms,
312: int want_keepalive, int needpriv, const char *proxy_command)
1.1 deraadt 313: {
1.90 markus 314: int gaierr;
315: int on = 1;
1.49 markus 316: int sock = -1, attempt;
1.90 markus 317: char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1.49 markus 318: struct addrinfo hints, *ai, *aitop;
1.38 markus 319:
1.136 markus 320: debug2("ssh_connect: needpriv %d", needpriv);
1.38 markus 321:
322: /* If a proxy command is given, connect using it. */
323: if (proxy_command != NULL)
1.124 markus 324: return ssh_proxy_connect(host, port, proxy_command);
1.38 markus 325:
326: /* No proxy command. */
327:
1.49 markus 328: memset(&hints, 0, sizeof(hints));
1.115 markus 329: hints.ai_family = family;
1.49 markus 330: hints.ai_socktype = SOCK_STREAM;
1.126 deraadt 331: snprintf(strport, sizeof strport, "%u", port);
1.49 markus 332: if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
1.203 dtucker 333: fatal("%s: Could not resolve hostname %.100s: %s", __progname,
334: host, ssh_gai_strerror(gaierr));
1.38 markus 335:
1.181 markus 336: for (attempt = 0; attempt < connection_attempts; attempt++) {
1.200 markus 337: if (attempt > 0) {
338: /* Sleep a moment before retrying. */
339: sleep(1);
1.38 markus 340: debug("Trying again...");
1.200 markus 341: }
1.181 markus 342: /*
343: * Loop through addresses for this host, and try each one in
344: * sequence until the connection succeeds.
345: */
1.49 markus 346: for (ai = aitop; ai; ai = ai->ai_next) {
347: if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
348: continue;
349: if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
350: ntop, sizeof(ntop), strport, sizeof(strport),
351: NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
352: error("ssh_connect: getnameinfo failed");
353: continue;
354: }
355: debug("Connecting to %.200s [%.100s] port %s.",
356: host, ntop, strport);
357:
358: /* Create a socket for connecting. */
1.139 markus 359: sock = ssh_create_socket(needpriv, ai);
1.49 markus 360: if (sock < 0)
1.110 markus 361: /* Any error is already output */
1.49 markus 362: continue;
363:
1.141 djm 364: if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
1.202 djm 365: timeout_ms) >= 0) {
1.49 markus 366: /* Successful connection. */
1.102 markus 367: memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
1.38 markus 368: break;
1.49 markus 369: } else {
1.131 itojun 370: debug("connect to address %s port %s: %s",
371: ntop, strport, strerror(errno));
1.38 markus 372: close(sock);
1.181 markus 373: sock = -1;
1.38 markus 374: }
375: }
1.181 markus 376: if (sock != -1)
1.49 markus 377: break; /* Successful connection. */
1.38 markus 378: }
1.49 markus 379:
380: freeaddrinfo(aitop);
381:
1.38 markus 382: /* Return failure if we didn't get a successful connection. */
1.181 markus 383: if (sock == -1) {
1.159 markus 384: error("ssh: connect to host %s port %s: %s",
1.130 itojun 385: host, strport, strerror(errno));
1.159 markus 386: return (-1);
1.130 itojun 387: }
1.38 markus 388:
389: debug("Connection established.");
1.90 markus 390:
1.155 markus 391: /* Set SO_KEEPALIVE if requested. */
1.202 djm 392: if (want_keepalive &&
1.90 markus 393: setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
394: sizeof(on)) < 0)
395: error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1.38 markus 396:
397: /* Set the connection. */
398: packet_set_connection(sock, sock);
1.207 dtucker 399: packet_set_timeout(options.server_alive_interval,
400: options.server_alive_count_max);
1.1 deraadt 401:
1.110 markus 402: return 0;
1.59 markus 403: }
404:
1.43 markus 405: /*
1.39 deraadt 406: * Waits for the server identification string, and sends our own
407: * identification string.
408: */
1.213 andreas 409: void
1.202 djm 410: ssh_exchange_identification(int timeout_ms)
1.1 deraadt 411: {
1.38 markus 412: char buf[256], remote_version[256]; /* must be same size! */
1.165 djm 413: int remote_major, remote_minor, mismatch;
1.38 markus 414: int connection_in = packet_get_connection_in();
415: int connection_out = packet_get_connection_out();
1.93 stevesk 416: int minor1 = PROTOCOL_MINOR_1;
1.185 djm 417: u_int i, n;
1.202 djm 418: size_t len;
419: int fdsetsz, remaining, rc;
420: struct timeval t_start, t_remaining;
421: fd_set *fdset;
422:
423: fdsetsz = howmany(connection_in + 1, NFDBITS) * sizeof(fd_mask);
424: fdset = xcalloc(1, fdsetsz);
1.38 markus 425:
1.163 avsm 426: /* Read other side's version identification. */
1.202 djm 427: remaining = timeout_ms;
1.185 djm 428: for (n = 0;;) {
1.75 markus 429: for (i = 0; i < sizeof(buf) - 1; i++) {
1.202 djm 430: if (timeout_ms > 0) {
431: gettimeofday(&t_start, NULL);
432: ms_to_timeval(&t_remaining, remaining);
433: FD_SET(connection_in, fdset);
434: rc = select(connection_in + 1, fdset, NULL,
435: fdset, &t_remaining);
436: ms_subtract_diff(&t_start, &remaining);
437: if (rc == 0 || remaining <= 0)
438: fatal("Connection timed out during "
439: "banner exchange");
440: if (rc == -1) {
441: if (errno == EINTR)
442: continue;
443: fatal("ssh_exchange_identification: "
444: "select: %s", strerror(errno));
445: }
446: }
447:
1.214 andreas 448: len = roaming_atomicio(read, connection_in, &buf[i], 1);
1.163 avsm 449:
1.167 djm 450: if (len != 1 && errno == EPIPE)
1.202 djm 451: fatal("ssh_exchange_identification: "
452: "Connection closed by remote host");
1.163 avsm 453: else if (len != 1)
1.202 djm 454: fatal("ssh_exchange_identification: "
455: "read: %.100s", strerror(errno));
1.75 markus 456: if (buf[i] == '\r') {
457: buf[i] = '\n';
458: buf[i + 1] = 0;
459: continue; /**XXX wait for \n */
460: }
461: if (buf[i] == '\n') {
462: buf[i + 1] = 0;
463: break;
464: }
1.185 djm 465: if (++n > 65536)
1.202 djm 466: fatal("ssh_exchange_identification: "
467: "No banner received");
1.38 markus 468: }
1.75 markus 469: buf[sizeof(buf) - 1] = 0;
1.76 markus 470: if (strncmp(buf, "SSH-", 4) == 0)
1.38 markus 471: break;
1.75 markus 472: debug("ssh_exchange_identification: %s", buf);
1.38 markus 473: }
1.59 markus 474: server_version_string = xstrdup(buf);
1.202 djm 475: xfree(fdset);
1.38 markus 476:
1.40 markus 477: /*
478: * Check that the versions match. In future this might accept
479: * several versions and set appropriate flags to handle them.
480: */
1.59 markus 481: if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
482: &remote_major, &remote_minor, remote_version) != 3)
1.38 markus 483: fatal("Bad remote protocol version identification: '%.100s'", buf);
484: debug("Remote protocol version %d.%d, remote software version %.100s",
1.118 deraadt 485: remote_major, remote_minor, remote_version);
1.38 markus 486:
1.59 markus 487: compat_datafellows(remote_version);
1.64 markus 488: mismatch = 0;
1.59 markus 489:
1.116 deraadt 490: switch (remote_major) {
1.64 markus 491: case 1:
492: if (remote_minor == 99 &&
493: (options.protocol & SSH_PROTO_2) &&
494: !(options.protocol & SSH_PROTO_1_PREFERRED)) {
495: enable_compat20();
496: break;
497: }
498: if (!(options.protocol & SSH_PROTO_1)) {
499: mismatch = 1;
500: break;
501: }
502: if (remote_minor < 3) {
503: fatal("Remote machine has too old SSH software version.");
1.81 markus 504: } else if (remote_minor == 3 || remote_minor == 4) {
1.64 markus 505: /* We speak 1.3, too. */
506: enable_compat13();
1.81 markus 507: minor1 = 3;
1.64 markus 508: if (options.forward_agent) {
1.138 itojun 509: logit("Agent forwarding disabled for protocol 1.3");
1.64 markus 510: options.forward_agent = 0;
511: }
512: }
513: break;
514: case 2:
515: if (options.protocol & SSH_PROTO_2) {
516: enable_compat20();
517: break;
1.38 markus 518: }
1.64 markus 519: /* FALLTHROUGH */
1.68 markus 520: default:
1.64 markus 521: mismatch = 1;
522: break;
1.38 markus 523: }
1.64 markus 524: if (mismatch)
1.38 markus 525: fatal("Protocol major versions differ: %d vs. %d",
1.64 markus 526: (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
527: remote_major);
1.38 markus 528: /* Send our own protocol version identification. */
1.211 dtucker 529: snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s%s",
1.64 markus 530: compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
1.81 markus 531: compat20 ? PROTOCOL_MINOR_2 : minor1,
1.211 dtucker 532: SSH_VERSION, compat20 ? "\r\n" : "\n");
1.214 andreas 533: if (roaming_atomicio(vwrite, connection_out, buf, strlen(buf))
534: != strlen(buf))
1.38 markus 535: fatal("write: %.100s", strerror(errno));
1.59 markus 536: client_version_string = xstrdup(buf);
537: chop(client_version_string);
538: chop(server_version_string);
539: debug("Local version string %.100s", client_version_string);
1.1 deraadt 540: }
541:
1.96 markus 542: /* defaults to 'no' */
1.109 itojun 543: static int
1.112 markus 544: confirm(const char *prompt)
1.1 deraadt 545: {
1.119 markus 546: const char *msg, *again = "Please type 'yes' or 'no': ";
547: char *p;
548: int ret = -1;
1.96 markus 549:
550: if (options.batch_mode)
551: return 0;
1.119 markus 552: for (msg = prompt;;msg = again) {
553: p = read_passphrase(msg, RP_ECHO);
554: if (p == NULL ||
555: (p[0] == '\0') || (p[0] == '\n') ||
556: strncasecmp(p, "no", 2) == 0)
557: ret = 0;
1.127 markus 558: if (p && strncasecmp(p, "yes", 3) == 0)
1.119 markus 559: ret = 1;
560: if (p)
561: xfree(p);
562: if (ret != -1)
563: return ret;
1.1 deraadt 564: }
565: }
566:
1.39 deraadt 567: /*
1.108 markus 568: * check whether the supplied host key is valid, return -1 if the key
569: * is not valid. the user_hostfile will not be updated if 'readonly' is true.
1.39 deraadt 570: */
1.197 dtucker 571: #define RDRW 0
572: #define RDONLY 1
573: #define ROQUIET 2
1.109 itojun 574: static int
1.197 dtucker 575: check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port,
576: Key *host_key, int readonly, const char *user_hostfile,
577: const char *system_hostfile)
1.1 deraadt 578: {
1.58 markus 579: Key *file_key;
1.152 jakob 580: const char *type = key_type(host_key);
1.189 dtucker 581: char *ip = NULL, *host = NULL;
1.204 grunk 582: char hostline[1000], *hostp, *fp, *ra;
1.38 markus 583: HostStatus host_status;
584: HostStatus ip_status;
1.161 djm 585: int r, local = 0, host_ip_differ = 0;
1.49 markus 586: char ntop[NI_MAXHOST];
1.119 markus 587: char msg[1024];
1.210 dtucker 588: int len, host_line, ip_line, cancelled_forwarding = 0;
1.85 markus 589: const char *host_file = NULL, *ip_file = NULL;
1.49 markus 590:
591: /*
592: * Force accepting of the host key for loopback/localhost. The
593: * problem is that if the home directory is NFS-mounted to multiple
594: * machines, localhost will refer to a different machine in each of
595: * them, and the user will get bogus HOST_CHANGED warnings. This
596: * essentially disables host authentication for localhost; however,
597: * this is probably not a real problem.
598: */
1.70 markus 599: /** hostaddr == 0! */
1.49 markus 600: switch (hostaddr->sa_family) {
601: case AF_INET:
1.108 markus 602: local = (ntohl(((struct sockaddr_in *)hostaddr)->
1.168 djm 603: sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
1.49 markus 604: break;
605: case AF_INET6:
1.108 markus 606: local = IN6_IS_ADDR_LOOPBACK(
607: &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
1.49 markus 608: break;
609: default:
610: local = 0;
611: break;
612: }
1.111 markus 613: if (options.no_host_authentication_for_localhost == 1 && local &&
614: options.host_key_alias == NULL) {
1.88 markus 615: debug("Forcing accepting of host key for "
616: "loopback/localhost.");
1.108 markus 617: return 0;
1.49 markus 618: }
1.42 markus 619:
620: /*
1.88 markus 621: * We don't have the remote ip-address for connections
622: * using a proxy command
1.42 markus 623: */
1.84 markus 624: if (options.proxy_command == NULL) {
625: if (getnameinfo(hostaddr, hostaddr->sa_len, ntop, sizeof(ntop),
1.86 markus 626: NULL, 0, NI_NUMERICHOST) != 0)
1.84 markus 627: fatal("check_host_key: getnameinfo failed");
1.197 dtucker 628: ip = put_host_port(ntop, port);
1.84 markus 629: } else {
630: ip = xstrdup("<no hostip for proxy command>");
1.86 markus 631: }
1.206 grunk 632:
633: /*
1.88 markus 634: * Turn off check_host_ip if the connection is to localhost, via proxy
635: * command or if we don't have a hostname to compare with
636: */
1.189 dtucker 637: if (options.check_host_ip && (local ||
638: strcmp(hostname, ip) == 0 || options.proxy_command != NULL))
1.88 markus 639: options.check_host_ip = 0;
1.86 markus 640:
641: /*
1.189 dtucker 642: * Allow the user to record the key under a different name or
643: * differentiate a non-standard port. This is useful for ssh
644: * tunneling over forwarded connections or if you run multiple
645: * sshd's on different ports on the same machine.
1.86 markus 646: */
647: if (options.host_key_alias != NULL) {
1.189 dtucker 648: host = xstrdup(options.host_key_alias);
1.86 markus 649: debug("using hostkeyalias: %s", host);
1.189 dtucker 650: } else {
1.197 dtucker 651: host = put_host_port(hostname, port);
1.84 markus 652: }
1.38 markus 653:
1.46 markus 654: /*
655: * Store the host key from the known host file in here so that we can
656: * compare it with the key for the IP address.
657: */
1.58 markus 658: file_key = key_new(host_key->type);
1.38 markus 659:
1.40 markus 660: /*
1.170 djm 661: * Check if the host key is present in the user's list of known
1.40 markus 662: * hosts or in the systemwide list.
663: */
1.85 markus 664: host_file = user_hostfile;
1.108 markus 665: host_status = check_host_in_hostfile(host_file, host, host_key,
1.118 deraadt 666: file_key, &host_line);
1.85 markus 667: if (host_status == HOST_NEW) {
668: host_file = system_hostfile;
1.108 markus 669: host_status = check_host_in_hostfile(host_file, host, host_key,
670: file_key, &host_line);
1.85 markus 671: }
1.40 markus 672: /*
673: * Also perform check for the ip address, skip the check if we are
674: * localhost or the hostname was an ip address to begin with
675: */
1.88 markus 676: if (options.check_host_ip) {
1.58 markus 677: Key *ip_key = key_new(host_key->type);
1.38 markus 678:
1.85 markus 679: ip_file = user_hostfile;
1.108 markus 680: ip_status = check_host_in_hostfile(ip_file, ip, host_key,
681: ip_key, &ip_line);
1.85 markus 682: if (ip_status == HOST_NEW) {
683: ip_file = system_hostfile;
1.108 markus 684: ip_status = check_host_in_hostfile(ip_file, ip,
685: host_key, ip_key, &ip_line);
1.85 markus 686: }
1.38 markus 687: if (host_status == HOST_CHANGED &&
1.58 markus 688: (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
1.38 markus 689: host_ip_differ = 1;
690:
1.58 markus 691: key_free(ip_key);
1.38 markus 692: } else
693: ip_status = host_status;
694:
1.58 markus 695: key_free(file_key);
1.38 markus 696:
697: switch (host_status) {
698: case HOST_OK:
699: /* The host is known and the key matches. */
1.72 markus 700: debug("Host '%.200s' is known and matches the %s host key.",
701: host, type);
1.85 markus 702: debug("Found key in %s:%d", host_file, host_line);
1.88 markus 703: if (options.check_host_ip && ip_status == HOST_NEW) {
1.108 markus 704: if (readonly)
1.138 itojun 705: logit("%s host key for IP address "
1.108 markus 706: "'%.128s' not in list of known hosts.",
707: type, ip);
708: else if (!add_host_to_hostfile(user_hostfile, ip,
1.160 djm 709: host_key, options.hash_known_hosts))
1.138 itojun 710: logit("Failed to add the %s host key for IP "
1.108 markus 711: "address '%.128s' to the list of known "
712: "hosts (%.30s).", type, ip, user_hostfile);
1.88 markus 713: else
1.138 itojun 714: logit("Warning: Permanently added the %s host "
1.108 markus 715: "key for IP address '%.128s' to the list "
716: "of known hosts.", type, ip);
1.209 grunk 717: } else if (options.visual_host_key) {
1.204 grunk 718: fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
719: ra = key_fingerprint(host_key, SSH_FP_MD5,
720: SSH_FP_RANDOMART);
721: logit("Host key fingerprint is %s\n%s\n", fp, ra);
722: xfree(ra);
723: xfree(fp);
1.38 markus 724: }
725: break;
726: case HOST_NEW:
1.197 dtucker 727: if (options.host_key_alias == NULL && port != 0 &&
728: port != SSH_DEFAULT_PORT) {
729: debug("checking without port identifier");
1.212 stevesk 730: if (check_host_key(hostname, hostaddr, 0, host_key,
731: ROQUIET, user_hostfile, system_hostfile) == 0) {
1.197 dtucker 732: debug("found matching key w/out port");
733: break;
734: }
735: }
1.108 markus 736: if (readonly)
737: goto fail;
1.38 markus 738: /* The host is new. */
739: if (options.strict_host_key_checking == 1) {
1.108 markus 740: /*
741: * User has requested strict host key checking. We
742: * will not add the host key automatically. The only
743: * alternative left is to abort.
744: */
745: error("No %s host key is known for %.200s and you "
746: "have requested strict checking.", type, host);
747: goto fail;
1.38 markus 748: } else if (options.strict_host_key_checking == 2) {
1.145 jakob 749: char msg1[1024], msg2[1024];
750:
751: if (show_other_keys(host, host_key))
752: snprintf(msg1, sizeof(msg1),
1.168 djm 753: "\nbut keys of different type are already"
754: " known for this host.");
1.145 jakob 755: else
756: snprintf(msg1, sizeof(msg1), ".");
1.38 markus 757: /* The default */
1.100 markus 758: fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1.204 grunk 759: ra = key_fingerprint(host_key, SSH_FP_MD5,
760: SSH_FP_RANDOMART);
1.145 jakob 761: msg2[0] = '\0';
762: if (options.verify_host_key_dns) {
1.153 jakob 763: if (matching_host_key_dns)
1.145 jakob 764: snprintf(msg2, sizeof(msg2),
765: "Matching host key fingerprint"
766: " found in DNS.\n");
767: else
768: snprintf(msg2, sizeof(msg2),
769: "No matching host key fingerprint"
770: " found in DNS.\n");
771: }
1.119 markus 772: snprintf(msg, sizeof(msg),
1.108 markus 773: "The authenticity of host '%.200s (%s)' can't be "
1.132 markus 774: "established%s\n"
1.209 grunk 775: "%s key fingerprint is %s.%s%s\n%s"
1.108 markus 776: "Are you sure you want to continue connecting "
1.132 markus 777: "(yes/no)? ",
1.209 grunk 778: host, ip, msg1, type, fp,
779: options.visual_host_key ? "\n" : "",
780: options.visual_host_key ? ra : "",
781: msg2);
1.204 grunk 782: xfree(ra);
1.100 markus 783: xfree(fp);
1.119 markus 784: if (!confirm(msg))
1.108 markus 785: goto fail;
1.38 markus 786: }
1.161 djm 787: /*
788: * If not in strict mode, add the key automatically to the
789: * local known_hosts file.
790: */
1.88 markus 791: if (options.check_host_ip && ip_status == HOST_NEW) {
1.161 djm 792: snprintf(hostline, sizeof(hostline), "%s,%s",
793: host, ip);
1.38 markus 794: hostp = hostline;
1.161 djm 795: if (options.hash_known_hosts) {
796: /* Add hash of host and IP separately */
797: r = add_host_to_hostfile(user_hostfile, host,
798: host_key, options.hash_known_hosts) &&
799: add_host_to_hostfile(user_hostfile, ip,
800: host_key, options.hash_known_hosts);
801: } else {
802: /* Add unhashed "host,ip" */
803: r = add_host_to_hostfile(user_hostfile,
804: hostline, host_key,
805: options.hash_known_hosts);
806: }
807: } else {
808: r = add_host_to_hostfile(user_hostfile, host, host_key,
809: options.hash_known_hosts);
1.38 markus 810: hostp = host;
1.161 djm 811: }
1.38 markus 812:
1.161 djm 813: if (!r)
1.138 itojun 814: logit("Failed to add the host to the list of known "
1.108 markus 815: "hosts (%.500s).", user_hostfile);
1.38 markus 816: else
1.138 itojun 817: logit("Warning: Permanently added '%.200s' (%s) to the "
1.108 markus 818: "list of known hosts.", hostp, type);
1.38 markus 819: break;
820: case HOST_CHANGED:
1.197 dtucker 821: if (readonly == ROQUIET)
822: goto fail;
1.38 markus 823: if (options.check_host_ip && host_ip_differ) {
1.158 avsm 824: char *key_msg;
1.38 markus 825: if (ip_status == HOST_NEW)
1.158 avsm 826: key_msg = "is unknown";
1.38 markus 827: else if (ip_status == HOST_OK)
1.158 avsm 828: key_msg = "is unchanged";
1.38 markus 829: else
1.158 avsm 830: key_msg = "has a different value";
1.38 markus 831: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
832: error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
833: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1.72 markus 834: error("The %s host key for %s has changed,", type, host);
1.208 ian 835: error("and the key for the corresponding IP address %s", ip);
1.158 avsm 836: error("%s. This could either mean that", key_msg);
1.38 markus 837: error("DNS SPOOFING is happening or the IP address for the host");
1.85 markus 838: error("and its host key have changed at the same time.");
1.88 markus 839: if (ip_status != HOST_NEW)
1.85 markus 840: error("Offending key for IP in %s:%d", ip_file, ip_line);
1.38 markus 841: }
842: /* The host key has changed. */
1.150 jakob 843: warn_changed_key(host_key);
1.38 markus 844: error("Add correct host key in %.100s to get rid of this message.",
1.87 markus 845: user_hostfile);
1.85 markus 846: error("Offending key in %s:%d", host_file, host_line);
1.38 markus 847:
1.40 markus 848: /*
849: * If strict host key checking is in use, the user will have
850: * to edit the key manually and we can only abort.
851: */
1.108 markus 852: if (options.strict_host_key_checking) {
853: error("%s host key for %.200s has changed and you have "
854: "requested strict checking.", type, host);
855: goto fail;
856: }
1.38 markus 857:
1.40 markus 858: /*
859: * If strict host key checking has not been requested, allow
1.144 djm 860: * the connection but without MITM-able authentication or
1.194 stevesk 861: * forwarding.
1.40 markus 862: */
1.38 markus 863: if (options.password_authentication) {
1.108 markus 864: error("Password authentication is disabled to avoid "
865: "man-in-the-middle attacks.");
1.38 markus 866: options.password_authentication = 0;
1.210 dtucker 867: cancelled_forwarding = 1;
1.144 djm 868: }
869: if (options.kbd_interactive_authentication) {
870: error("Keyboard-interactive authentication is disabled"
871: " to avoid man-in-the-middle attacks.");
872: options.kbd_interactive_authentication = 0;
873: options.challenge_response_authentication = 0;
1.210 dtucker 874: cancelled_forwarding = 1;
1.144 djm 875: }
876: if (options.challenge_response_authentication) {
877: error("Challenge/response authentication is disabled"
878: " to avoid man-in-the-middle attacks.");
879: options.challenge_response_authentication = 0;
1.210 dtucker 880: cancelled_forwarding = 1;
1.38 markus 881: }
882: if (options.forward_agent) {
1.108 markus 883: error("Agent forwarding is disabled to avoid "
884: "man-in-the-middle attacks.");
1.38 markus 885: options.forward_agent = 0;
1.210 dtucker 886: cancelled_forwarding = 1;
1.83 markus 887: }
888: if (options.forward_x11) {
1.108 markus 889: error("X11 forwarding is disabled to avoid "
890: "man-in-the-middle attacks.");
1.83 markus 891: options.forward_x11 = 0;
1.210 dtucker 892: cancelled_forwarding = 1;
1.83 markus 893: }
1.108 markus 894: if (options.num_local_forwards > 0 ||
895: options.num_remote_forwards > 0) {
896: error("Port forwarding is disabled to avoid "
897: "man-in-the-middle attacks.");
898: options.num_local_forwards =
1.118 deraadt 899: options.num_remote_forwards = 0;
1.210 dtucker 900: cancelled_forwarding = 1;
1.194 stevesk 901: }
902: if (options.tun_open != SSH_TUNMODE_NO) {
903: error("Tunnel forwarding is disabled to avoid "
904: "man-in-the-middle attacks.");
905: options.tun_open = SSH_TUNMODE_NO;
1.210 dtucker 906: cancelled_forwarding = 1;
1.38 markus 907: }
1.210 dtucker 908: if (options.exit_on_forward_failure && cancelled_forwarding)
909: fatal("Error: forwarding disabled due to host key "
910: "check failure");
911:
1.40 markus 912: /*
913: * XXX Should permit the user to change to use the new id.
914: * This could be done by converting the host key to an
915: * identifying sentence, tell that the host identifies itself
916: * by that sentence, and ask the user if he/she whishes to
917: * accept the authentication.
918: */
1.38 markus 919: break;
1.132 markus 920: case HOST_FOUND:
921: fatal("internal error");
922: break;
1.88 markus 923: }
924:
925: if (options.check_host_ip && host_status != HOST_CHANGED &&
926: ip_status == HOST_CHANGED) {
1.119 markus 927: snprintf(msg, sizeof(msg),
928: "Warning: the %s host key for '%.200s' "
929: "differs from the key for the IP address '%.128s'"
930: "\nOffending key for IP in %s:%d",
931: type, host, ip, ip_file, ip_line);
932: if (host_status == HOST_OK) {
933: len = strlen(msg);
934: snprintf(msg + len, sizeof(msg) - len,
935: "\nMatching host key in %s:%d",
1.125 deraadt 936: host_file, host_line);
1.119 markus 937: }
1.88 markus 938: if (options.strict_host_key_checking == 1) {
1.143 djm 939: logit("%s", msg);
1.108 markus 940: error("Exiting, you have requested strict checking.");
941: goto fail;
1.88 markus 942: } else if (options.strict_host_key_checking == 2) {
1.119 markus 943: strlcat(msg, "\nAre you sure you want "
944: "to continue connecting (yes/no)? ", sizeof(msg));
945: if (!confirm(msg))
1.108 markus 946: goto fail;
1.119 markus 947: } else {
1.143 djm 948: logit("%s", msg);
1.88 markus 949: }
1.38 markus 950: }
1.82 provos 951:
952: xfree(ip);
1.189 dtucker 953: xfree(host);
1.108 markus 954: return 0;
955:
956: fail:
957: xfree(ip);
1.189 dtucker 958: xfree(host);
1.108 markus 959: return -1;
960: }
961:
1.140 jakob 962: /* returns 0 if key verifies or -1 if key does NOT verify */
1.108 markus 963: int
964: verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
965: {
966: struct stat st;
1.153 jakob 967: int flags = 0;
1.140 jakob 968:
1.153 jakob 969: if (options.verify_host_key_dns &&
970: verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
971:
972: if (flags & DNS_VERIFY_FOUND) {
973:
974: if (options.verify_host_key_dns == 1 &&
975: flags & DNS_VERIFY_MATCH &&
976: flags & DNS_VERIFY_SECURE)
977: return 0;
978:
979: if (flags & DNS_VERIFY_MATCH) {
980: matching_host_key_dns = 1;
981: } else {
982: warn_changed_key(host_key);
983: error("Update the SSHFP RR in DNS with the new "
984: "host key to get rid of this message.");
985: }
1.140 jakob 986: }
987: }
1.108 markus 988:
989: /* return ok if the key can be found in an old keyfile */
990: if (stat(options.system_hostfile2, &st) == 0 ||
991: stat(options.user_hostfile2, &st) == 0) {
1.197 dtucker 992: if (check_host_key(host, hostaddr, options.port, host_key,
993: RDONLY, options.user_hostfile2,
994: options.system_hostfile2) == 0)
1.108 markus 995: return 0;
996: }
1.197 dtucker 997: return check_host_key(host, hostaddr, options.port, host_key,
998: RDRW, options.user_hostfile, options.system_hostfile);
1.51 markus 999: }
1.70 markus 1000:
1.51 markus 1001: /*
1002: * Starts a dialog with the server, and authenticates the current user on the
1003: * server. This does not need any extra privileges. The basic connection
1004: * to the server must already have been established before this is called.
1005: * If login fails, this function prints an error and never returns.
1006: * This function does not require super-user privileges.
1007: */
1008: void
1.120 markus 1009: ssh_login(Sensitive *sensitive, const char *orighost,
1.202 djm 1010: struct sockaddr *hostaddr, struct passwd *pw, int timeout_ms)
1.51 markus 1011: {
1012: char *host, *cp;
1.70 markus 1013: char *server_user, *local_user;
1014:
1015: local_user = xstrdup(pw->pw_name);
1016: server_user = options.user ? options.user : local_user;
1.51 markus 1017:
1018: /* Convert the user-supplied hostname into all lowercase. */
1019: host = xstrdup(orighost);
1020: for (cp = host; *cp; cp++)
1021: if (isupper(*cp))
1.178 deraadt 1022: *cp = (char)tolower(*cp);
1.51 markus 1023:
1024: /* Exchange protocol version identification strings with the server. */
1.202 djm 1025: ssh_exchange_identification(timeout_ms);
1.51 markus 1026:
1027: /* Put the connection into non-blocking mode. */
1028: packet_set_nonblocking();
1029:
1030: /* key exchange */
1031: /* authenticate user */
1.59 markus 1032: if (compat20) {
1033: ssh_kex2(host, hostaddr);
1.120 markus 1034: ssh_userauth2(local_user, server_user, host, sensitive);
1.59 markus 1035: } else {
1036: ssh_kex(host, hostaddr);
1.120 markus 1037: ssh_userauth1(local_user, server_user, host, sensitive);
1.59 markus 1038: }
1.182 markus 1039: xfree(local_user);
1.97 markus 1040: }
1041:
1042: void
1043: ssh_put_password(char *password)
1044: {
1045: int size;
1046: char *padded;
1047:
1.99 deraadt 1048: if (datafellows & SSH_BUG_PASSWORDPAD) {
1.107 markus 1049: packet_put_cstring(password);
1.99 deraadt 1050: return;
1051: }
1.97 markus 1052: size = roundup(strlen(password) + 1, 32);
1.179 djm 1053: padded = xcalloc(1, size);
1.97 markus 1054: strlcpy(padded, password, size);
1055: packet_put_string(padded, size);
1056: memset(padded, 0, size);
1057: xfree(padded);
1.132 markus 1058: }
1059:
1060: static int
1061: show_key_from_file(const char *file, const char *host, int keytype)
1062: {
1063: Key *found;
1.204 grunk 1064: char *fp, *ra;
1.132 markus 1065: int line, ret;
1066:
1067: found = key_new(keytype);
1068: if ((ret = lookup_key_in_hostfile_by_type(file, host,
1069: keytype, found, &line))) {
1070: fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
1.204 grunk 1071: ra = key_fingerprint(found, SSH_FP_MD5, SSH_FP_RANDOMART);
1.138 itojun 1072: logit("WARNING: %s key found for host %s\n"
1.133 markus 1073: "in %s:%d\n"
1.204 grunk 1074: "%s key fingerprint %s.\n%s\n",
1.132 markus 1075: key_type(found), host, file, line,
1.204 grunk 1076: key_type(found), fp, ra);
1077: xfree(ra);
1.132 markus 1078: xfree(fp);
1079: }
1080: key_free(found);
1081: return (ret);
1082: }
1083:
1084: /* print all known host keys for a given host, but skip keys of given type */
1085: static int
1086: show_other_keys(const char *host, Key *key)
1087: {
1088: int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, -1};
1089: int i, found = 0;
1090:
1091: for (i = 0; type[i] != -1; i++) {
1092: if (type[i] == key->type)
1093: continue;
1094: if (type[i] != KEY_RSA1 &&
1095: show_key_from_file(options.user_hostfile2, host, type[i])) {
1096: found = 1;
1097: continue;
1098: }
1099: if (type[i] != KEY_RSA1 &&
1100: show_key_from_file(options.system_hostfile2, host, type[i])) {
1101: found = 1;
1102: continue;
1103: }
1104: if (show_key_from_file(options.user_hostfile, host, type[i])) {
1105: found = 1;
1106: continue;
1107: }
1108: if (show_key_from_file(options.system_hostfile, host, type[i])) {
1109: found = 1;
1110: continue;
1111: }
1112: debug2("no key of type %d for host %s", type[i], host);
1113: }
1114: return (found);
1.150 jakob 1115: }
1116:
1117: static void
1118: warn_changed_key(Key *host_key)
1119: {
1120: char *fp;
1.151 jakob 1121: const char *type = key_type(host_key);
1.150 jakob 1122:
1123: fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1124:
1125: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1126: error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
1127: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1128: error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
1129: error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
1130: error("It is also possible that the %s host key has just been changed.", type);
1131: error("The fingerprint for the %s key sent by the remote host is\n%s.",
1132: type, fp);
1133: error("Please contact your system administrator.");
1134:
1135: xfree(fp);
1.171 reyk 1136: }
1137:
1138: /*
1139: * Execute a local command
1140: */
1141: int
1142: ssh_local_cmd(const char *args)
1143: {
1144: char *shell;
1145: pid_t pid;
1146: int status;
1147:
1148: if (!options.permit_local_command ||
1149: args == NULL || !*args)
1150: return (1);
1151:
1152: if ((shell = getenv("SHELL")) == NULL)
1153: shell = _PATH_BSHELL;
1154:
1155: pid = fork();
1156: if (pid == 0) {
1157: debug3("Executing %s -c \"%s\"", shell, args);
1158: execl(shell, shell, "-c", args, (char *)NULL);
1159: error("Couldn't execute %s -c \"%s\": %s",
1160: shell, args, strerror(errno));
1161: _exit(1);
1162: } else if (pid == -1)
1163: fatal("fork failed: %.100s", strerror(errno));
1164: while (waitpid(pid, &status, 0) == -1)
1165: if (errno != EINTR)
1166: fatal("Couldn't wait for child: %s", strerror(errno));
1167:
1168: if (!WIFEXITED(status))
1169: return (1);
1170:
1171: return (WEXITSTATUS(status));
1.1 deraadt 1172: }
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