Annotation of src/usr.bin/ssh/sshconnect.c, Revision 1.236
1.236 ! markus 1: /* $OpenBSD: sshconnect.c,v 1.235 2012/08/17 01:30:00 djm 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>
1.216 dtucker 26: #include <fcntl.h>
1.191 stevesk 27: #include <netdb.h>
1.172 stevesk 28: #include <paths.h>
1.199 deraadt 29: #include <signal.h>
1.188 stevesk 30: #include <pwd.h>
1.198 stevesk 31: #include <stdio.h>
1.196 stevesk 32: #include <stdlib.h>
1.193 stevesk 33: #include <string.h>
1.192 stevesk 34: #include <unistd.h>
1.71 markus 35:
1.199 deraadt 36: #include "xmalloc.h"
1.91 markus 37: #include "ssh.h"
1.1 deraadt 38: #include "rsa.h"
1.59 markus 39: #include "buffer.h"
1.1 deraadt 40: #include "packet.h"
41: #include "uidswap.h"
1.21 markus 42: #include "compat.h"
1.58 markus 43: #include "key.h"
1.71 markus 44: #include "sshconnect.h"
1.58 markus 45: #include "hostfile.h"
1.91 markus 46: #include "log.h"
47: #include "readconf.h"
48: #include "atomicio.h"
49: #include "misc.h"
1.140 jakob 50: #include "dns.h"
1.214 andreas 51: #include "roaming.h"
1.219 djm 52: #include "ssh2.h"
1.186 stevesk 53: #include "version.h"
1.140 jakob 54:
1.70 markus 55: char *client_version_string = NULL;
56: char *server_version_string = NULL;
1.59 markus 57:
1.169 stevesk 58: static int matching_host_key_dns = 0;
1.145 jakob 59:
1.227 djm 60: static pid_t proxy_command_pid = 0;
61:
1.124 markus 62: /* import */
1.43 markus 63: extern Options options;
1.50 markus 64: extern char *__progname;
1.124 markus 65: extern uid_t original_real_uid;
66: extern uid_t original_effective_uid;
1.91 markus 67:
1.229 djm 68: static int show_other_keys(struct hostkeys *, Key *);
1.150 jakob 69: static void warn_changed_key(Key *);
1.132 markus 70:
1.39 deraadt 71: /*
72: * Connect to the given ssh server using a proxy command.
73: */
1.109 itojun 74: static int
1.124 markus 75: ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
1.1 deraadt 76: {
1.164 djm 77: char *command_string, *tmp;
1.38 markus 78: int pin[2], pout[2];
1.69 deraadt 79: pid_t pid;
1.201 djm 80: char *shell, strport[NI_MAXSERV];
81:
1.226 djm 82: if ((shell = getenv("SHELL")) == NULL || *shell == '\0')
1.201 djm 83: shell = _PATH_BSHELL;
1.38 markus 84:
85: /* Convert the port number into a string. */
1.49 markus 86: snprintf(strport, sizeof strport, "%hu", port);
1.38 markus 87:
1.135 djm 88: /*
89: * Build the final command string in the buffer by making the
90: * appropriate substitutions to the given proxy command.
91: *
1.154 djm 92: * Use "exec" to avoid "sh -c" processes on some platforms
1.135 djm 93: * (e.g. Solaris)
94: */
1.179 djm 95: xasprintf(&tmp, "exec %s", proxy_command);
1.222 djm 96: command_string = percent_expand(tmp, "h", host, "p", strport,
1.224 djm 97: "r", options.user, (char *)NULL);
1.164 djm 98: xfree(tmp);
1.38 markus 99:
100: /* Create pipes for communicating with the proxy. */
101: if (pipe(pin) < 0 || pipe(pout) < 0)
102: fatal("Could not create pipes to communicate with the proxy: %.100s",
1.118 deraadt 103: strerror(errno));
1.38 markus 104:
105: debug("Executing proxy command: %.500s", command_string);
106:
107: /* Fork and execute the proxy command. */
108: if ((pid = fork()) == 0) {
109: char *argv[10];
110:
111: /* Child. Permanently give up superuser privileges. */
1.184 markus 112: permanently_drop_suid(original_real_uid);
1.38 markus 113:
114: /* Redirect stdin and stdout. */
115: close(pin[1]);
116: if (pin[0] != 0) {
117: if (dup2(pin[0], 0) < 0)
118: perror("dup2 stdin");
119: close(pin[0]);
120: }
121: close(pout[0]);
122: if (dup2(pout[1], 1) < 0)
123: perror("dup2 stdout");
124: /* Cannot be 1 because pin allocated two descriptors. */
125: close(pout[1]);
126:
127: /* Stderr is left as it is so that error messages get
128: printed on the user's terminal. */
1.201 djm 129: argv[0] = shell;
1.38 markus 130: argv[1] = "-c";
131: argv[2] = command_string;
132: argv[3] = NULL;
133:
134: /* Execute the proxy command. Note that we gave up any
135: extra privileges above. */
1.232 djm 136: signal(SIGPIPE, SIG_DFL);
1.89 markus 137: execv(argv[0], argv);
138: perror(argv[0]);
1.38 markus 139: exit(1);
140: }
141: /* Parent. */
142: if (pid < 0)
143: fatal("fork failed: %.100s", strerror(errno));
1.135 djm 144: else
145: proxy_command_pid = pid; /* save pid to clean up later */
1.38 markus 146:
147: /* Close child side of the descriptors. */
148: close(pin[0]);
149: close(pout[1]);
150:
151: /* Free the command name. */
1.164 djm 152: xfree(command_string);
1.38 markus 153:
154: /* Set the connection file descriptors. */
155: packet_set_connection(pout[0], pin[1]);
1.207 dtucker 156: packet_set_timeout(options.server_alive_interval,
157: options.server_alive_count_max);
1.1 deraadt 158:
1.110 markus 159: /* Indicate OK return */
160: return 0;
1.227 djm 161: }
162:
163: void
164: ssh_kill_proxy_command(void)
165: {
166: /*
167: * Send SIGHUP to proxy command if used. We don't wait() in
168: * case it hangs and instead rely on init to reap the child
169: */
170: if (proxy_command_pid > 1)
1.228 djm 171: kill(proxy_command_pid, SIGHUP);
1.1 deraadt 172: }
173:
1.39 deraadt 174: /*
175: * Creates a (possibly privileged) socket for use as the ssh connection.
176: */
1.109 itojun 177: static int
1.139 markus 178: ssh_create_socket(int privileged, struct addrinfo *ai)
1.1 deraadt 179: {
1.105 markus 180: int sock, gaierr;
181: struct addrinfo hints, *res;
1.1 deraadt 182:
1.40 markus 183: /*
184: * If we are running as root and want to connect to a privileged
185: * port, bind our own socket to a privileged port.
186: */
1.38 markus 187: if (privileged) {
188: int p = IPPORT_RESERVED - 1;
1.124 markus 189: PRIV_START;
1.139 markus 190: sock = rresvport_af(&p, ai->ai_family);
1.124 markus 191: PRIV_END;
1.38 markus 192: if (sock < 0)
1.139 markus 193: error("rresvport: af=%d %.100s", ai->ai_family,
194: strerror(errno));
1.55 markus 195: else
196: debug("Allocated local port %d.", p);
1.105 markus 197: return sock;
198: }
1.217 dtucker 199: sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
1.216 dtucker 200: if (sock < 0) {
1.105 markus 201: error("socket: %.100s", strerror(errno));
1.216 dtucker 202: return -1;
203: }
204: fcntl(sock, F_SETFD, FD_CLOEXEC);
1.105 markus 205:
206: /* Bind the socket to an alternative local IP address */
207: if (options.bind_address == NULL)
208: return sock;
209:
210: memset(&hints, 0, sizeof(hints));
1.139 markus 211: hints.ai_family = ai->ai_family;
212: hints.ai_socktype = ai->ai_socktype;
213: hints.ai_protocol = ai->ai_protocol;
1.105 markus 214: hints.ai_flags = AI_PASSIVE;
1.205 dtucker 215: gaierr = getaddrinfo(options.bind_address, NULL, &hints, &res);
1.105 markus 216: if (gaierr) {
217: error("getaddrinfo: %s: %s", options.bind_address,
1.203 dtucker 218: ssh_gai_strerror(gaierr));
1.105 markus 219: close(sock);
220: return -1;
221: }
222: if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
223: error("bind: %s: %s", options.bind_address, strerror(errno));
224: close(sock);
225: freeaddrinfo(res);
226: return -1;
1.38 markus 227: }
1.105 markus 228: freeaddrinfo(res);
1.38 markus 229: return sock;
1.1 deraadt 230: }
231:
1.141 djm 232: static int
233: timeout_connect(int sockfd, const struct sockaddr *serv_addr,
1.202 djm 234: socklen_t addrlen, int *timeoutp)
1.141 djm 235: {
236: fd_set *fdset;
1.202 djm 237: struct timeval tv, t_start;
1.141 djm 238: socklen_t optlen;
1.179 djm 239: int optval, rc, result = -1;
1.141 djm 240:
1.202 djm 241: gettimeofday(&t_start, NULL);
242:
243: if (*timeoutp <= 0) {
244: result = connect(sockfd, serv_addr, addrlen);
245: goto done;
246: }
1.141 djm 247:
1.156 djm 248: set_nonblock(sockfd);
1.141 djm 249: rc = connect(sockfd, serv_addr, addrlen);
1.156 djm 250: if (rc == 0) {
251: unset_nonblock(sockfd);
1.202 djm 252: result = 0;
253: goto done;
254: }
255: if (errno != EINPROGRESS) {
256: result = -1;
257: goto done;
1.156 djm 258: }
1.141 djm 259:
1.179 djm 260: fdset = (fd_set *)xcalloc(howmany(sockfd + 1, NFDBITS),
261: sizeof(fd_mask));
1.141 djm 262: FD_SET(sockfd, fdset);
1.202 djm 263: ms_to_timeval(&tv, *timeoutp);
1.141 djm 264:
1.162 deraadt 265: for (;;) {
1.141 djm 266: rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
267: if (rc != -1 || errno != EINTR)
268: break;
269: }
270:
1.162 deraadt 271: switch (rc) {
1.141 djm 272: case 0:
273: /* Timed out */
274: errno = ETIMEDOUT;
1.142 djm 275: break;
1.141 djm 276: case -1:
277: /* Select error */
1.154 djm 278: debug("select: %s", strerror(errno));
1.142 djm 279: break;
1.141 djm 280: case 1:
281: /* Completed or failed */
282: optval = 0;
283: optlen = sizeof(optval);
1.154 djm 284: if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval,
1.148 markus 285: &optlen) == -1) {
1.154 djm 286: debug("getsockopt: %s", strerror(errno));
1.142 djm 287: break;
1.148 markus 288: }
1.141 djm 289: if (optval != 0) {
290: errno = optval;
1.142 djm 291: break;
1.141 djm 292: }
1.142 djm 293: result = 0;
1.156 djm 294: unset_nonblock(sockfd);
1.141 djm 295: break;
296: default:
297: /* Should not occur */
298: fatal("Bogus return (%d) from select()", rc);
299: }
300:
1.142 djm 301: xfree(fdset);
1.202 djm 302:
303: done:
304: if (result == 0 && *timeoutp > 0) {
305: ms_subtract_diff(&t_start, timeoutp);
306: if (*timeoutp <= 0) {
307: errno = ETIMEDOUT;
308: result = -1;
309: }
310: }
311:
1.142 djm 312: return (result);
1.141 djm 313: }
314:
1.39 deraadt 315: /*
1.49 markus 316: * Opens a TCP/IP connection to the remote server on the given host.
317: * The address of the remote host will be returned in hostaddr.
1.124 markus 318: * If port is 0, the default port will be used. If needpriv is true,
1.39 deraadt 319: * a privileged port will be allocated to make the connection.
1.124 markus 320: * This requires super-user privileges if needpriv is true.
1.39 deraadt 321: * Connection_attempts specifies the maximum number of tries (one per
322: * second). If proxy_command is non-NULL, it specifies the command (with %h
323: * and %p substituted for host and port, respectively) to use to contact
324: * the daemon.
325: */
1.38 markus 326: int
1.49 markus 327: ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
1.202 djm 328: u_short port, int family, int connection_attempts, int *timeout_ms,
329: int want_keepalive, int needpriv, const char *proxy_command)
1.1 deraadt 330: {
1.90 markus 331: int gaierr;
332: int on = 1;
1.49 markus 333: int sock = -1, attempt;
1.90 markus 334: char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1.49 markus 335: struct addrinfo hints, *ai, *aitop;
1.38 markus 336:
1.136 markus 337: debug2("ssh_connect: needpriv %d", needpriv);
1.38 markus 338:
339: /* If a proxy command is given, connect using it. */
340: if (proxy_command != NULL)
1.124 markus 341: return ssh_proxy_connect(host, port, proxy_command);
1.38 markus 342:
343: /* No proxy command. */
344:
1.49 markus 345: memset(&hints, 0, sizeof(hints));
1.115 markus 346: hints.ai_family = family;
1.49 markus 347: hints.ai_socktype = SOCK_STREAM;
1.126 deraadt 348: snprintf(strport, sizeof strport, "%u", port);
1.49 markus 349: if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
1.203 dtucker 350: fatal("%s: Could not resolve hostname %.100s: %s", __progname,
351: host, ssh_gai_strerror(gaierr));
1.38 markus 352:
1.181 markus 353: for (attempt = 0; attempt < connection_attempts; attempt++) {
1.200 markus 354: if (attempt > 0) {
355: /* Sleep a moment before retrying. */
356: sleep(1);
1.38 markus 357: debug("Trying again...");
1.200 markus 358: }
1.181 markus 359: /*
360: * Loop through addresses for this host, and try each one in
361: * sequence until the connection succeeds.
362: */
1.49 markus 363: for (ai = aitop; ai; ai = ai->ai_next) {
364: if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
365: continue;
366: if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
367: ntop, sizeof(ntop), strport, sizeof(strport),
368: NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
369: error("ssh_connect: getnameinfo failed");
370: continue;
371: }
372: debug("Connecting to %.200s [%.100s] port %s.",
373: host, ntop, strport);
374:
375: /* Create a socket for connecting. */
1.139 markus 376: sock = ssh_create_socket(needpriv, ai);
1.49 markus 377: if (sock < 0)
1.110 markus 378: /* Any error is already output */
1.49 markus 379: continue;
380:
1.141 djm 381: if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
1.202 djm 382: timeout_ms) >= 0) {
1.49 markus 383: /* Successful connection. */
1.102 markus 384: memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
1.38 markus 385: break;
1.49 markus 386: } else {
1.131 itojun 387: debug("connect to address %s port %s: %s",
388: ntop, strport, strerror(errno));
1.38 markus 389: close(sock);
1.181 markus 390: sock = -1;
1.38 markus 391: }
392: }
1.181 markus 393: if (sock != -1)
1.49 markus 394: break; /* Successful connection. */
1.38 markus 395: }
1.49 markus 396:
397: freeaddrinfo(aitop);
398:
1.38 markus 399: /* Return failure if we didn't get a successful connection. */
1.181 markus 400: if (sock == -1) {
1.159 markus 401: error("ssh: connect to host %s port %s: %s",
1.130 itojun 402: host, strport, strerror(errno));
1.159 markus 403: return (-1);
1.130 itojun 404: }
1.38 markus 405:
406: debug("Connection established.");
1.90 markus 407:
1.155 markus 408: /* Set SO_KEEPALIVE if requested. */
1.202 djm 409: if (want_keepalive &&
1.90 markus 410: setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
411: sizeof(on)) < 0)
412: error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1.38 markus 413:
414: /* Set the connection. */
415: packet_set_connection(sock, sock);
1.207 dtucker 416: packet_set_timeout(options.server_alive_interval,
417: options.server_alive_count_max);
1.1 deraadt 418:
1.110 markus 419: return 0;
1.59 markus 420: }
421:
1.235 djm 422: static void
423: send_client_banner(int connection_out, int minor1)
424: {
425: /* Send our own protocol version identification. */
426: if (compat20) {
427: xasprintf(&client_version_string, "SSH-%d.%d-%.100s\r\n",
428: PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, SSH_VERSION);
429: } else {
430: xasprintf(&client_version_string, "SSH-%d.%d-%.100s\n",
431: PROTOCOL_MAJOR_1, minor1, SSH_VERSION);
432: }
433: if (roaming_atomicio(vwrite, connection_out, client_version_string,
434: strlen(client_version_string)) != strlen(client_version_string))
435: fatal("write: %.100s", strerror(errno));
436: chop(client_version_string);
437: debug("Local version string %.100s", client_version_string);
438: }
439:
1.43 markus 440: /*
1.39 deraadt 441: * Waits for the server identification string, and sends our own
442: * identification string.
443: */
1.213 andreas 444: void
1.202 djm 445: ssh_exchange_identification(int timeout_ms)
1.1 deraadt 446: {
1.38 markus 447: char buf[256], remote_version[256]; /* must be same size! */
1.165 djm 448: int remote_major, remote_minor, mismatch;
1.38 markus 449: int connection_in = packet_get_connection_in();
450: int connection_out = packet_get_connection_out();
1.235 djm 451: int minor1 = PROTOCOL_MINOR_1, client_banner_sent = 0;
1.185 djm 452: u_int i, n;
1.202 djm 453: size_t len;
454: int fdsetsz, remaining, rc;
455: struct timeval t_start, t_remaining;
456: fd_set *fdset;
457:
458: fdsetsz = howmany(connection_in + 1, NFDBITS) * sizeof(fd_mask);
459: fdset = xcalloc(1, fdsetsz);
1.38 markus 460:
1.235 djm 461: /*
462: * If we are SSH2-only then we can send the banner immediately and
463: * save a round-trip.
464: */
465: if (options.protocol == SSH_PROTO_2) {
466: enable_compat20();
467: send_client_banner(connection_out, 0);
468: client_banner_sent = 1;
469: }
470:
1.163 avsm 471: /* Read other side's version identification. */
1.202 djm 472: remaining = timeout_ms;
1.185 djm 473: for (n = 0;;) {
1.75 markus 474: for (i = 0; i < sizeof(buf) - 1; i++) {
1.202 djm 475: if (timeout_ms > 0) {
476: gettimeofday(&t_start, NULL);
477: ms_to_timeval(&t_remaining, remaining);
478: FD_SET(connection_in, fdset);
479: rc = select(connection_in + 1, fdset, NULL,
480: fdset, &t_remaining);
481: ms_subtract_diff(&t_start, &remaining);
482: if (rc == 0 || remaining <= 0)
483: fatal("Connection timed out during "
484: "banner exchange");
485: if (rc == -1) {
486: if (errno == EINTR)
487: continue;
488: fatal("ssh_exchange_identification: "
489: "select: %s", strerror(errno));
490: }
491: }
492:
1.214 andreas 493: len = roaming_atomicio(read, connection_in, &buf[i], 1);
1.163 avsm 494:
1.167 djm 495: if (len != 1 && errno == EPIPE)
1.202 djm 496: fatal("ssh_exchange_identification: "
497: "Connection closed by remote host");
1.163 avsm 498: else if (len != 1)
1.202 djm 499: fatal("ssh_exchange_identification: "
500: "read: %.100s", strerror(errno));
1.75 markus 501: if (buf[i] == '\r') {
502: buf[i] = '\n';
503: buf[i + 1] = 0;
504: continue; /**XXX wait for \n */
505: }
506: if (buf[i] == '\n') {
507: buf[i + 1] = 0;
508: break;
509: }
1.185 djm 510: if (++n > 65536)
1.202 djm 511: fatal("ssh_exchange_identification: "
512: "No banner received");
1.38 markus 513: }
1.75 markus 514: buf[sizeof(buf) - 1] = 0;
1.76 markus 515: if (strncmp(buf, "SSH-", 4) == 0)
1.38 markus 516: break;
1.75 markus 517: debug("ssh_exchange_identification: %s", buf);
1.38 markus 518: }
1.59 markus 519: server_version_string = xstrdup(buf);
1.202 djm 520: xfree(fdset);
1.38 markus 521:
1.40 markus 522: /*
523: * Check that the versions match. In future this might accept
524: * several versions and set appropriate flags to handle them.
525: */
1.59 markus 526: if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
527: &remote_major, &remote_minor, remote_version) != 3)
1.38 markus 528: fatal("Bad remote protocol version identification: '%.100s'", buf);
529: debug("Remote protocol version %d.%d, remote software version %.100s",
1.118 deraadt 530: remote_major, remote_minor, remote_version);
1.38 markus 531:
1.59 markus 532: compat_datafellows(remote_version);
1.64 markus 533: mismatch = 0;
1.59 markus 534:
1.116 deraadt 535: switch (remote_major) {
1.64 markus 536: case 1:
537: if (remote_minor == 99 &&
538: (options.protocol & SSH_PROTO_2) &&
539: !(options.protocol & SSH_PROTO_1_PREFERRED)) {
540: enable_compat20();
541: break;
542: }
543: if (!(options.protocol & SSH_PROTO_1)) {
544: mismatch = 1;
545: break;
546: }
547: if (remote_minor < 3) {
548: fatal("Remote machine has too old SSH software version.");
1.81 markus 549: } else if (remote_minor == 3 || remote_minor == 4) {
1.64 markus 550: /* We speak 1.3, too. */
551: enable_compat13();
1.81 markus 552: minor1 = 3;
1.64 markus 553: if (options.forward_agent) {
1.138 itojun 554: logit("Agent forwarding disabled for protocol 1.3");
1.64 markus 555: options.forward_agent = 0;
556: }
557: }
558: break;
559: case 2:
560: if (options.protocol & SSH_PROTO_2) {
561: enable_compat20();
562: break;
1.38 markus 563: }
1.64 markus 564: /* FALLTHROUGH */
1.68 markus 565: default:
1.64 markus 566: mismatch = 1;
567: break;
1.38 markus 568: }
1.64 markus 569: if (mismatch)
1.38 markus 570: fatal("Protocol major versions differ: %d vs. %d",
1.64 markus 571: (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
572: remote_major);
1.235 djm 573: if (!client_banner_sent)
574: send_client_banner(connection_out, minor1);
1.59 markus 575: chop(server_version_string);
1.1 deraadt 576: }
577:
1.96 markus 578: /* defaults to 'no' */
1.109 itojun 579: static int
1.112 markus 580: confirm(const char *prompt)
1.1 deraadt 581: {
1.119 markus 582: const char *msg, *again = "Please type 'yes' or 'no': ";
583: char *p;
584: int ret = -1;
1.96 markus 585:
586: if (options.batch_mode)
587: return 0;
1.119 markus 588: for (msg = prompt;;msg = again) {
589: p = read_passphrase(msg, RP_ECHO);
590: if (p == NULL ||
591: (p[0] == '\0') || (p[0] == '\n') ||
592: strncasecmp(p, "no", 2) == 0)
593: ret = 0;
1.127 markus 594: if (p && strncasecmp(p, "yes", 3) == 0)
1.119 markus 595: ret = 1;
596: if (p)
597: xfree(p);
598: if (ret != -1)
599: return ret;
1.1 deraadt 600: }
601: }
602:
1.219 djm 603: static int
604: check_host_cert(const char *host, const Key *host_key)
605: {
606: const char *reason;
607:
608: if (key_cert_check_authority(host_key, 1, 0, host, &reason) != 0) {
609: error("%s", reason);
610: return 0;
611: }
1.223 djm 612: if (buffer_len(&host_key->cert->critical) != 0) {
613: error("Certificate for %s contains unsupported "
614: "critical options(s)", host);
1.219 djm 615: return 0;
616: }
617: return 1;
618: }
619:
1.229 djm 620: static int
621: sockaddr_is_local(struct sockaddr *hostaddr)
622: {
623: switch (hostaddr->sa_family) {
624: case AF_INET:
625: return (ntohl(((struct sockaddr_in *)hostaddr)->
626: sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
627: case AF_INET6:
628: return IN6_IS_ADDR_LOOPBACK(
629: &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
630: default:
631: return 0;
632: }
633: }
634:
635: /*
636: * Prepare the hostname and ip address strings that are used to lookup
637: * host keys in known_hosts files. These may have a port number appended.
638: */
639: void
640: get_hostfile_hostname_ipaddr(char *hostname, struct sockaddr *hostaddr,
641: u_short port, char **hostfile_hostname, char **hostfile_ipaddr)
642: {
643: char ntop[NI_MAXHOST];
644:
645: /*
646: * We don't have the remote ip-address for connections
647: * using a proxy command
648: */
649: if (hostfile_ipaddr != NULL) {
650: if (options.proxy_command == NULL) {
651: if (getnameinfo(hostaddr, hostaddr->sa_len,
652: ntop, sizeof(ntop), NULL, 0, NI_NUMERICHOST) != 0)
653: fatal("check_host_key: getnameinfo failed");
654: *hostfile_ipaddr = put_host_port(ntop, port);
655: } else {
656: *hostfile_ipaddr = xstrdup("<no hostip for proxy "
657: "command>");
658: }
659: }
660:
661: /*
662: * Allow the user to record the key under a different name or
663: * differentiate a non-standard port. This is useful for ssh
664: * tunneling over forwarded connections or if you run multiple
665: * sshd's on different ports on the same machine.
666: */
667: if (hostfile_hostname != NULL) {
668: if (options.host_key_alias != NULL) {
669: *hostfile_hostname = xstrdup(options.host_key_alias);
670: debug("using hostkeyalias: %s", *hostfile_hostname);
671: } else {
672: *hostfile_hostname = put_host_port(hostname, port);
673: }
674: }
675: }
676:
1.39 deraadt 677: /*
1.108 markus 678: * check whether the supplied host key is valid, return -1 if the key
1.234 djm 679: * is not valid. user_hostfile[0] will not be updated if 'readonly' is true.
1.39 deraadt 680: */
1.197 dtucker 681: #define RDRW 0
682: #define RDONLY 1
683: #define ROQUIET 2
1.109 itojun 684: static int
1.197 dtucker 685: check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port,
1.234 djm 686: Key *host_key, int readonly,
687: char **user_hostfiles, u_int num_user_hostfiles,
688: char **system_hostfiles, u_int num_system_hostfiles)
1.1 deraadt 689: {
1.234 djm 690: HostStatus host_status;
691: HostStatus ip_status;
1.229 djm 692: Key *raw_key = NULL;
1.189 dtucker 693: char *ip = NULL, *host = NULL;
1.204 grunk 694: char hostline[1000], *hostp, *fp, *ra;
1.119 markus 695: char msg[1024];
1.234 djm 696: const char *type;
697: const struct hostkey_entry *host_found, *ip_found;
1.229 djm 698: int len, cancelled_forwarding = 0;
1.234 djm 699: int local = sockaddr_is_local(hostaddr);
700: int r, want_cert = key_is_cert(host_key), host_ip_differ = 0;
1.229 djm 701: struct hostkeys *host_hostkeys, *ip_hostkeys;
1.234 djm 702: u_int i;
1.49 markus 703:
704: /*
705: * Force accepting of the host key for loopback/localhost. The
706: * problem is that if the home directory is NFS-mounted to multiple
707: * machines, localhost will refer to a different machine in each of
708: * them, and the user will get bogus HOST_CHANGED warnings. This
709: * essentially disables host authentication for localhost; however,
710: * this is probably not a real problem.
711: */
1.111 markus 712: if (options.no_host_authentication_for_localhost == 1 && local &&
713: options.host_key_alias == NULL) {
1.88 markus 714: debug("Forcing accepting of host key for "
715: "loopback/localhost.");
1.108 markus 716: return 0;
1.49 markus 717: }
1.42 markus 718:
719: /*
1.229 djm 720: * Prepare the hostname and address strings used for hostkey lookup.
721: * In some cases, these will have a port number appended.
1.42 markus 722: */
1.229 djm 723: get_hostfile_hostname_ipaddr(hostname, hostaddr, port, &host, &ip);
1.206 grunk 724:
725: /*
1.88 markus 726: * Turn off check_host_ip if the connection is to localhost, via proxy
727: * command or if we don't have a hostname to compare with
728: */
1.189 dtucker 729: if (options.check_host_ip && (local ||
730: strcmp(hostname, ip) == 0 || options.proxy_command != NULL))
1.88 markus 731: options.check_host_ip = 0;
1.86 markus 732:
1.229 djm 733: host_hostkeys = init_hostkeys();
1.234 djm 734: for (i = 0; i < num_user_hostfiles; i++)
735: load_hostkeys(host_hostkeys, host, user_hostfiles[i]);
736: for (i = 0; i < num_system_hostfiles; i++)
737: load_hostkeys(host_hostkeys, host, system_hostfiles[i]);
1.229 djm 738:
739: ip_hostkeys = NULL;
740: if (!want_cert && options.check_host_ip) {
741: ip_hostkeys = init_hostkeys();
1.234 djm 742: for (i = 0; i < num_user_hostfiles; i++)
743: load_hostkeys(ip_hostkeys, ip, user_hostfiles[i]);
744: for (i = 0; i < num_system_hostfiles; i++)
745: load_hostkeys(ip_hostkeys, ip, system_hostfiles[i]);
1.84 markus 746: }
1.38 markus 747:
1.219 djm 748: retry:
1.229 djm 749: /* Reload these as they may have changed on cert->key downgrade */
1.219 djm 750: want_cert = key_is_cert(host_key);
751: type = key_type(host_key);
752:
1.46 markus 753: /*
1.170 djm 754: * Check if the host key is present in the user's list of known
1.40 markus 755: * hosts or in the systemwide list.
756: */
1.229 djm 757: host_status = check_key_in_hostkeys(host_hostkeys, host_key,
758: &host_found);
759:
1.40 markus 760: /*
761: * Also perform check for the ip address, skip the check if we are
1.219 djm 762: * localhost, looking for a certificate, or the hostname was an ip
763: * address to begin with.
1.40 markus 764: */
1.229 djm 765: if (!want_cert && ip_hostkeys != NULL) {
766: ip_status = check_key_in_hostkeys(ip_hostkeys, host_key,
767: &ip_found);
1.38 markus 768: if (host_status == HOST_CHANGED &&
1.229 djm 769: (ip_status != HOST_CHANGED ||
770: (ip_found != NULL &&
771: !key_equal(ip_found->key, host_found->key))))
1.38 markus 772: host_ip_differ = 1;
773: } else
774: ip_status = host_status;
775:
776: switch (host_status) {
777: case HOST_OK:
778: /* The host is known and the key matches. */
1.219 djm 779: debug("Host '%.200s' is known and matches the %s host %s.",
780: host, type, want_cert ? "certificate" : "key");
1.229 djm 781: debug("Found %s in %s:%lu", want_cert ? "CA key" : "key",
782: host_found->file, host_found->line);
1.219 djm 783: if (want_cert && !check_host_cert(hostname, host_key))
784: goto fail;
1.88 markus 785: if (options.check_host_ip && ip_status == HOST_NEW) {
1.219 djm 786: if (readonly || want_cert)
1.138 itojun 787: logit("%s host key for IP address "
1.108 markus 788: "'%.128s' not in list of known hosts.",
789: type, ip);
1.234 djm 790: else if (!add_host_to_hostfile(user_hostfiles[0], ip,
1.160 djm 791: host_key, options.hash_known_hosts))
1.138 itojun 792: logit("Failed to add the %s host key for IP "
1.108 markus 793: "address '%.128s' to the list of known "
1.234 djm 794: "hosts (%.30s).", type, ip,
795: user_hostfiles[0]);
1.88 markus 796: else
1.138 itojun 797: logit("Warning: Permanently added the %s host "
1.108 markus 798: "key for IP address '%.128s' to the list "
799: "of known hosts.", type, ip);
1.209 grunk 800: } else if (options.visual_host_key) {
1.204 grunk 801: fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
802: ra = key_fingerprint(host_key, SSH_FP_MD5,
803: SSH_FP_RANDOMART);
804: logit("Host key fingerprint is %s\n%s\n", fp, ra);
805: xfree(ra);
806: xfree(fp);
1.38 markus 807: }
808: break;
809: case HOST_NEW:
1.197 dtucker 810: if (options.host_key_alias == NULL && port != 0 &&
811: port != SSH_DEFAULT_PORT) {
812: debug("checking without port identifier");
1.212 stevesk 813: if (check_host_key(hostname, hostaddr, 0, host_key,
1.234 djm 814: ROQUIET, user_hostfiles, num_user_hostfiles,
815: system_hostfiles, num_system_hostfiles) == 0) {
1.197 dtucker 816: debug("found matching key w/out port");
817: break;
818: }
819: }
1.219 djm 820: if (readonly || want_cert)
1.108 markus 821: goto fail;
1.38 markus 822: /* The host is new. */
823: if (options.strict_host_key_checking == 1) {
1.108 markus 824: /*
825: * User has requested strict host key checking. We
826: * will not add the host key automatically. The only
827: * alternative left is to abort.
828: */
829: error("No %s host key is known for %.200s and you "
830: "have requested strict checking.", type, host);
831: goto fail;
1.38 markus 832: } else if (options.strict_host_key_checking == 2) {
1.145 jakob 833: char msg1[1024], msg2[1024];
834:
1.229 djm 835: if (show_other_keys(host_hostkeys, host_key))
1.145 jakob 836: snprintf(msg1, sizeof(msg1),
1.168 djm 837: "\nbut keys of different type are already"
838: " known for this host.");
1.145 jakob 839: else
840: snprintf(msg1, sizeof(msg1), ".");
1.38 markus 841: /* The default */
1.100 markus 842: fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1.204 grunk 843: ra = key_fingerprint(host_key, SSH_FP_MD5,
844: SSH_FP_RANDOMART);
1.145 jakob 845: msg2[0] = '\0';
846: if (options.verify_host_key_dns) {
1.153 jakob 847: if (matching_host_key_dns)
1.145 jakob 848: snprintf(msg2, sizeof(msg2),
849: "Matching host key fingerprint"
850: " found in DNS.\n");
851: else
852: snprintf(msg2, sizeof(msg2),
853: "No matching host key fingerprint"
854: " found in DNS.\n");
855: }
1.119 markus 856: snprintf(msg, sizeof(msg),
1.108 markus 857: "The authenticity of host '%.200s (%s)' can't be "
1.132 markus 858: "established%s\n"
1.209 grunk 859: "%s key fingerprint is %s.%s%s\n%s"
1.108 markus 860: "Are you sure you want to continue connecting "
1.132 markus 861: "(yes/no)? ",
1.209 grunk 862: host, ip, msg1, type, fp,
863: options.visual_host_key ? "\n" : "",
864: options.visual_host_key ? ra : "",
865: msg2);
1.204 grunk 866: xfree(ra);
1.100 markus 867: xfree(fp);
1.119 markus 868: if (!confirm(msg))
1.108 markus 869: goto fail;
1.38 markus 870: }
1.161 djm 871: /*
872: * If not in strict mode, add the key automatically to the
873: * local known_hosts file.
874: */
1.88 markus 875: if (options.check_host_ip && ip_status == HOST_NEW) {
1.229 djm 876: snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
1.38 markus 877: hostp = hostline;
1.161 djm 878: if (options.hash_known_hosts) {
879: /* Add hash of host and IP separately */
1.234 djm 880: r = add_host_to_hostfile(user_hostfiles[0],
881: host, host_key, options.hash_known_hosts) &&
882: add_host_to_hostfile(user_hostfiles[0], ip,
1.161 djm 883: host_key, options.hash_known_hosts);
884: } else {
885: /* Add unhashed "host,ip" */
1.234 djm 886: r = add_host_to_hostfile(user_hostfiles[0],
1.161 djm 887: hostline, host_key,
888: options.hash_known_hosts);
889: }
890: } else {
1.234 djm 891: r = add_host_to_hostfile(user_hostfiles[0], host,
892: host_key, options.hash_known_hosts);
1.38 markus 893: hostp = host;
1.161 djm 894: }
1.38 markus 895:
1.161 djm 896: if (!r)
1.138 itojun 897: logit("Failed to add the host to the list of known "
1.234 djm 898: "hosts (%.500s).", user_hostfiles[0]);
1.38 markus 899: else
1.138 itojun 900: logit("Warning: Permanently added '%.200s' (%s) to the "
1.108 markus 901: "list of known hosts.", hostp, type);
1.38 markus 902: break;
1.220 djm 903: case HOST_REVOKED:
904: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
905: error("@ WARNING: REVOKED HOST KEY DETECTED! @");
906: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
907: error("The %s host key for %s is marked as revoked.", type, host);
908: error("This could mean that a stolen key is being used to");
909: error("impersonate this host.");
910:
911: /*
912: * If strict host key checking is in use, the user will have
913: * to edit the key manually and we can only abort.
914: */
915: if (options.strict_host_key_checking) {
916: error("%s host key for %.200s was revoked and you have "
917: "requested strict checking.", type, host);
918: goto fail;
919: }
920: goto continue_unsafe;
921:
1.38 markus 922: case HOST_CHANGED:
1.219 djm 923: if (want_cert) {
924: /*
925: * This is only a debug() since it is valid to have
926: * CAs with wildcard DNS matches that don't match
927: * all hosts that one might visit.
928: */
929: debug("Host certificate authority does not "
1.229 djm 930: "match %s in %s:%lu", CA_MARKER,
931: host_found->file, host_found->line);
1.219 djm 932: goto fail;
933: }
1.197 dtucker 934: if (readonly == ROQUIET)
935: goto fail;
1.38 markus 936: if (options.check_host_ip && host_ip_differ) {
1.158 avsm 937: char *key_msg;
1.38 markus 938: if (ip_status == HOST_NEW)
1.158 avsm 939: key_msg = "is unknown";
1.38 markus 940: else if (ip_status == HOST_OK)
1.158 avsm 941: key_msg = "is unchanged";
1.38 markus 942: else
1.158 avsm 943: key_msg = "has a different value";
1.38 markus 944: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
945: error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
946: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1.72 markus 947: error("The %s host key for %s has changed,", type, host);
1.208 ian 948: error("and the key for the corresponding IP address %s", ip);
1.158 avsm 949: error("%s. This could either mean that", key_msg);
1.38 markus 950: error("DNS SPOOFING is happening or the IP address for the host");
1.85 markus 951: error("and its host key have changed at the same time.");
1.88 markus 952: if (ip_status != HOST_NEW)
1.229 djm 953: error("Offending key for IP in %s:%lu",
954: ip_found->file, ip_found->line);
1.38 markus 955: }
956: /* The host key has changed. */
1.150 jakob 957: warn_changed_key(host_key);
1.38 markus 958: error("Add correct host key in %.100s to get rid of this message.",
1.234 djm 959: user_hostfiles[0]);
1.229 djm 960: error("Offending %s key in %s:%lu", key_type(host_found->key),
961: host_found->file, host_found->line);
1.38 markus 962:
1.40 markus 963: /*
964: * If strict host key checking is in use, the user will have
965: * to edit the key manually and we can only abort.
966: */
1.108 markus 967: if (options.strict_host_key_checking) {
968: error("%s host key for %.200s has changed and you have "
969: "requested strict checking.", type, host);
970: goto fail;
971: }
1.38 markus 972:
1.220 djm 973: continue_unsafe:
1.40 markus 974: /*
975: * If strict host key checking has not been requested, allow
1.144 djm 976: * the connection but without MITM-able authentication or
1.194 stevesk 977: * forwarding.
1.40 markus 978: */
1.38 markus 979: if (options.password_authentication) {
1.108 markus 980: error("Password authentication is disabled to avoid "
981: "man-in-the-middle attacks.");
1.38 markus 982: options.password_authentication = 0;
1.210 dtucker 983: cancelled_forwarding = 1;
1.144 djm 984: }
985: if (options.kbd_interactive_authentication) {
986: error("Keyboard-interactive authentication is disabled"
987: " to avoid man-in-the-middle attacks.");
988: options.kbd_interactive_authentication = 0;
989: options.challenge_response_authentication = 0;
1.210 dtucker 990: cancelled_forwarding = 1;
1.144 djm 991: }
992: if (options.challenge_response_authentication) {
993: error("Challenge/response authentication is disabled"
994: " to avoid man-in-the-middle attacks.");
995: options.challenge_response_authentication = 0;
1.210 dtucker 996: cancelled_forwarding = 1;
1.38 markus 997: }
998: if (options.forward_agent) {
1.108 markus 999: error("Agent forwarding is disabled to avoid "
1000: "man-in-the-middle attacks.");
1.38 markus 1001: options.forward_agent = 0;
1.210 dtucker 1002: cancelled_forwarding = 1;
1.83 markus 1003: }
1004: if (options.forward_x11) {
1.108 markus 1005: error("X11 forwarding is disabled to avoid "
1006: "man-in-the-middle attacks.");
1.83 markus 1007: options.forward_x11 = 0;
1.210 dtucker 1008: cancelled_forwarding = 1;
1.83 markus 1009: }
1.108 markus 1010: if (options.num_local_forwards > 0 ||
1011: options.num_remote_forwards > 0) {
1012: error("Port forwarding is disabled to avoid "
1013: "man-in-the-middle attacks.");
1014: options.num_local_forwards =
1.118 deraadt 1015: options.num_remote_forwards = 0;
1.210 dtucker 1016: cancelled_forwarding = 1;
1.194 stevesk 1017: }
1018: if (options.tun_open != SSH_TUNMODE_NO) {
1019: error("Tunnel forwarding is disabled to avoid "
1020: "man-in-the-middle attacks.");
1021: options.tun_open = SSH_TUNMODE_NO;
1.210 dtucker 1022: cancelled_forwarding = 1;
1.38 markus 1023: }
1.210 dtucker 1024: if (options.exit_on_forward_failure && cancelled_forwarding)
1025: fatal("Error: forwarding disabled due to host key "
1026: "check failure");
1027:
1.40 markus 1028: /*
1029: * XXX Should permit the user to change to use the new id.
1030: * This could be done by converting the host key to an
1031: * identifying sentence, tell that the host identifies itself
1.218 dtucker 1032: * by that sentence, and ask the user if he/she wishes to
1.40 markus 1033: * accept the authentication.
1034: */
1.38 markus 1035: break;
1.132 markus 1036: case HOST_FOUND:
1037: fatal("internal error");
1038: break;
1.88 markus 1039: }
1040:
1041: if (options.check_host_ip && host_status != HOST_CHANGED &&
1042: ip_status == HOST_CHANGED) {
1.119 markus 1043: snprintf(msg, sizeof(msg),
1044: "Warning: the %s host key for '%.200s' "
1045: "differs from the key for the IP address '%.128s'"
1.229 djm 1046: "\nOffending key for IP in %s:%lu",
1047: type, host, ip, ip_found->file, ip_found->line);
1.119 markus 1048: if (host_status == HOST_OK) {
1049: len = strlen(msg);
1050: snprintf(msg + len, sizeof(msg) - len,
1.229 djm 1051: "\nMatching host key in %s:%lu",
1052: host_found->file, host_found->line);
1.119 markus 1053: }
1.88 markus 1054: if (options.strict_host_key_checking == 1) {
1.143 djm 1055: logit("%s", msg);
1.108 markus 1056: error("Exiting, you have requested strict checking.");
1057: goto fail;
1.88 markus 1058: } else if (options.strict_host_key_checking == 2) {
1.119 markus 1059: strlcat(msg, "\nAre you sure you want "
1060: "to continue connecting (yes/no)? ", sizeof(msg));
1061: if (!confirm(msg))
1.108 markus 1062: goto fail;
1.119 markus 1063: } else {
1.143 djm 1064: logit("%s", msg);
1.88 markus 1065: }
1.38 markus 1066: }
1.82 provos 1067:
1068: xfree(ip);
1.189 dtucker 1069: xfree(host);
1.229 djm 1070: if (host_hostkeys != NULL)
1071: free_hostkeys(host_hostkeys);
1072: if (ip_hostkeys != NULL)
1073: free_hostkeys(ip_hostkeys);
1.108 markus 1074: return 0;
1075:
1076: fail:
1.220 djm 1077: if (want_cert && host_status != HOST_REVOKED) {
1.219 djm 1078: /*
1079: * No matching certificate. Downgrade cert to raw key and
1080: * search normally.
1081: */
1082: debug("No matching CA found. Retry with plain key");
1083: raw_key = key_from_private(host_key);
1084: if (key_drop_cert(raw_key) != 0)
1085: fatal("Couldn't drop certificate");
1086: host_key = raw_key;
1087: goto retry;
1088: }
1089: if (raw_key != NULL)
1090: key_free(raw_key);
1.108 markus 1091: xfree(ip);
1.189 dtucker 1092: xfree(host);
1.229 djm 1093: if (host_hostkeys != NULL)
1094: free_hostkeys(host_hostkeys);
1095: if (ip_hostkeys != NULL)
1096: free_hostkeys(ip_hostkeys);
1.108 markus 1097: return -1;
1098: }
1099:
1.140 jakob 1100: /* returns 0 if key verifies or -1 if key does NOT verify */
1.108 markus 1101: int
1102: verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
1103: {
1.153 jakob 1104: int flags = 0;
1.229 djm 1105: char *fp;
1106:
1107: fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1108: debug("Server host key: %s %s", key_type(host_key), fp);
1109: xfree(fp);
1.140 jakob 1110:
1.219 djm 1111: /* XXX certs are not yet supported for DNS */
1112: if (!key_is_cert(host_key) && options.verify_host_key_dns &&
1.153 jakob 1113: verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
1114: if (flags & DNS_VERIFY_FOUND) {
1115:
1116: if (options.verify_host_key_dns == 1 &&
1117: flags & DNS_VERIFY_MATCH &&
1118: flags & DNS_VERIFY_SECURE)
1119: return 0;
1120:
1121: if (flags & DNS_VERIFY_MATCH) {
1122: matching_host_key_dns = 1;
1123: } else {
1124: warn_changed_key(host_key);
1125: error("Update the SSHFP RR in DNS with the new "
1126: "host key to get rid of this message.");
1127: }
1.140 jakob 1128: }
1129: }
1.108 markus 1130:
1.234 djm 1131: return check_host_key(host, hostaddr, options.port, host_key, RDRW,
1132: options.user_hostfiles, options.num_user_hostfiles,
1133: options.system_hostfiles, options.num_system_hostfiles);
1.51 markus 1134: }
1.70 markus 1135:
1.51 markus 1136: /*
1137: * Starts a dialog with the server, and authenticates the current user on the
1138: * server. This does not need any extra privileges. The basic connection
1139: * to the server must already have been established before this is called.
1140: * If login fails, this function prints an error and never returns.
1141: * This function does not require super-user privileges.
1142: */
1143: void
1.120 markus 1144: ssh_login(Sensitive *sensitive, const char *orighost,
1.229 djm 1145: struct sockaddr *hostaddr, u_short port, struct passwd *pw, int timeout_ms)
1.51 markus 1146: {
1147: char *host, *cp;
1.70 markus 1148: char *server_user, *local_user;
1149:
1150: local_user = xstrdup(pw->pw_name);
1151: server_user = options.user ? options.user : local_user;
1.51 markus 1152:
1153: /* Convert the user-supplied hostname into all lowercase. */
1154: host = xstrdup(orighost);
1155: for (cp = host; *cp; cp++)
1156: if (isupper(*cp))
1.178 deraadt 1157: *cp = (char)tolower(*cp);
1.51 markus 1158:
1159: /* Exchange protocol version identification strings with the server. */
1.202 djm 1160: ssh_exchange_identification(timeout_ms);
1.51 markus 1161:
1162: /* Put the connection into non-blocking mode. */
1163: packet_set_nonblocking();
1164:
1165: /* key exchange */
1166: /* authenticate user */
1.59 markus 1167: if (compat20) {
1.229 djm 1168: ssh_kex2(host, hostaddr, port);
1.120 markus 1169: ssh_userauth2(local_user, server_user, host, sensitive);
1.59 markus 1170: } else {
1171: ssh_kex(host, hostaddr);
1.120 markus 1172: ssh_userauth1(local_user, server_user, host, sensitive);
1.59 markus 1173: }
1.182 markus 1174: xfree(local_user);
1.97 markus 1175: }
1176:
1177: void
1178: ssh_put_password(char *password)
1179: {
1180: int size;
1181: char *padded;
1182:
1.99 deraadt 1183: if (datafellows & SSH_BUG_PASSWORDPAD) {
1.107 markus 1184: packet_put_cstring(password);
1.99 deraadt 1185: return;
1186: }
1.97 markus 1187: size = roundup(strlen(password) + 1, 32);
1.179 djm 1188: padded = xcalloc(1, size);
1.97 markus 1189: strlcpy(padded, password, size);
1190: packet_put_string(padded, size);
1191: memset(padded, 0, size);
1192: xfree(padded);
1.132 markus 1193: }
1194:
1195: /* print all known host keys for a given host, but skip keys of given type */
1196: static int
1.229 djm 1197: show_other_keys(struct hostkeys *hostkeys, Key *key)
1.132 markus 1198: {
1.225 djm 1199: int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, KEY_ECDSA, -1};
1.229 djm 1200: int i, ret = 0;
1201: char *fp, *ra;
1202: const struct hostkey_entry *found;
1.132 markus 1203:
1204: for (i = 0; type[i] != -1; i++) {
1205: if (type[i] == key->type)
1206: continue;
1.229 djm 1207: if (!lookup_key_in_hostkeys_by_type(hostkeys, type[i], &found))
1.132 markus 1208: continue;
1.229 djm 1209: fp = key_fingerprint(found->key, SSH_FP_MD5, SSH_FP_HEX);
1210: ra = key_fingerprint(found->key, SSH_FP_MD5, SSH_FP_RANDOMART);
1211: logit("WARNING: %s key found for host %s\n"
1212: "in %s:%lu\n"
1213: "%s key fingerprint %s.",
1214: key_type(found->key),
1215: found->host, found->file, found->line,
1216: key_type(found->key), fp);
1217: if (options.visual_host_key)
1218: logit("%s", ra);
1219: xfree(ra);
1220: xfree(fp);
1221: ret = 1;
1.132 markus 1222: }
1.229 djm 1223: return ret;
1.150 jakob 1224: }
1225:
1226: static void
1227: warn_changed_key(Key *host_key)
1228: {
1229: char *fp;
1230:
1231: fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1232:
1233: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1234: error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
1235: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1236: error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
1237: error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
1.230 markus 1238: error("It is also possible that a host key has just been changed.");
1.150 jakob 1239: error("The fingerprint for the %s key sent by the remote host is\n%s.",
1.230 markus 1240: key_type(host_key), fp);
1.150 jakob 1241: error("Please contact your system administrator.");
1242:
1243: xfree(fp);
1.171 reyk 1244: }
1245:
1246: /*
1247: * Execute a local command
1248: */
1249: int
1250: ssh_local_cmd(const char *args)
1251: {
1252: char *shell;
1253: pid_t pid;
1254: int status;
1.231 djm 1255: void (*osighand)(int);
1.171 reyk 1256:
1257: if (!options.permit_local_command ||
1258: args == NULL || !*args)
1259: return (1);
1260:
1.226 djm 1261: if ((shell = getenv("SHELL")) == NULL || *shell == '\0')
1.171 reyk 1262: shell = _PATH_BSHELL;
1263:
1.231 djm 1264: osighand = signal(SIGCHLD, SIG_DFL);
1.171 reyk 1265: pid = fork();
1266: if (pid == 0) {
1.232 djm 1267: signal(SIGPIPE, SIG_DFL);
1.171 reyk 1268: debug3("Executing %s -c \"%s\"", shell, args);
1269: execl(shell, shell, "-c", args, (char *)NULL);
1270: error("Couldn't execute %s -c \"%s\": %s",
1271: shell, args, strerror(errno));
1272: _exit(1);
1273: } else if (pid == -1)
1274: fatal("fork failed: %.100s", strerror(errno));
1275: while (waitpid(pid, &status, 0) == -1)
1276: if (errno != EINTR)
1277: fatal("Couldn't wait for child: %s", strerror(errno));
1.231 djm 1278: signal(SIGCHLD, osighand);
1.171 reyk 1279:
1280: if (!WIFEXITED(status))
1281: return (1);
1282:
1283: return (WEXITSTATUS(status));
1.1 deraadt 1284: }