Annotation of src/usr.bin/ssh/sshconnect.c, Revision 1.238
1.238 ! djm 1: /* $OpenBSD: sshconnect.c,v 1.237 2013/02/22 19:13:56 markus 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];
1.237 markus 81:
82: if (!strcmp(proxy_command, "-")) {
83: packet_set_connection(STDIN_FILENO, STDOUT_FILENO);
84: packet_set_timeout(options.server_alive_interval,
85: options.server_alive_count_max);
86: return 0;
87: }
1.201 djm 88:
1.226 djm 89: if ((shell = getenv("SHELL")) == NULL || *shell == '\0')
1.201 djm 90: shell = _PATH_BSHELL;
1.38 markus 91:
92: /* Convert the port number into a string. */
1.49 markus 93: snprintf(strport, sizeof strport, "%hu", port);
1.38 markus 94:
1.135 djm 95: /*
96: * Build the final command string in the buffer by making the
97: * appropriate substitutions to the given proxy command.
98: *
1.154 djm 99: * Use "exec" to avoid "sh -c" processes on some platforms
1.135 djm 100: * (e.g. Solaris)
101: */
1.179 djm 102: xasprintf(&tmp, "exec %s", proxy_command);
1.222 djm 103: command_string = percent_expand(tmp, "h", host, "p", strport,
1.224 djm 104: "r", options.user, (char *)NULL);
1.238 ! djm 105: free(tmp);
1.38 markus 106:
107: /* Create pipes for communicating with the proxy. */
108: if (pipe(pin) < 0 || pipe(pout) < 0)
109: fatal("Could not create pipes to communicate with the proxy: %.100s",
1.118 deraadt 110: strerror(errno));
1.38 markus 111:
112: debug("Executing proxy command: %.500s", command_string);
113:
114: /* Fork and execute the proxy command. */
115: if ((pid = fork()) == 0) {
116: char *argv[10];
117:
118: /* Child. Permanently give up superuser privileges. */
1.184 markus 119: permanently_drop_suid(original_real_uid);
1.38 markus 120:
121: /* Redirect stdin and stdout. */
122: close(pin[1]);
123: if (pin[0] != 0) {
124: if (dup2(pin[0], 0) < 0)
125: perror("dup2 stdin");
126: close(pin[0]);
127: }
128: close(pout[0]);
129: if (dup2(pout[1], 1) < 0)
130: perror("dup2 stdout");
131: /* Cannot be 1 because pin allocated two descriptors. */
132: close(pout[1]);
133:
134: /* Stderr is left as it is so that error messages get
135: printed on the user's terminal. */
1.201 djm 136: argv[0] = shell;
1.38 markus 137: argv[1] = "-c";
138: argv[2] = command_string;
139: argv[3] = NULL;
140:
141: /* Execute the proxy command. Note that we gave up any
142: extra privileges above. */
1.232 djm 143: signal(SIGPIPE, SIG_DFL);
1.89 markus 144: execv(argv[0], argv);
145: perror(argv[0]);
1.38 markus 146: exit(1);
147: }
148: /* Parent. */
149: if (pid < 0)
150: fatal("fork failed: %.100s", strerror(errno));
1.135 djm 151: else
152: proxy_command_pid = pid; /* save pid to clean up later */
1.38 markus 153:
154: /* Close child side of the descriptors. */
155: close(pin[0]);
156: close(pout[1]);
157:
158: /* Free the command name. */
1.238 ! djm 159: free(command_string);
1.38 markus 160:
161: /* Set the connection file descriptors. */
162: packet_set_connection(pout[0], pin[1]);
1.207 dtucker 163: packet_set_timeout(options.server_alive_interval,
164: options.server_alive_count_max);
1.1 deraadt 165:
1.110 markus 166: /* Indicate OK return */
167: return 0;
1.227 djm 168: }
169:
170: void
171: ssh_kill_proxy_command(void)
172: {
173: /*
174: * Send SIGHUP to proxy command if used. We don't wait() in
175: * case it hangs and instead rely on init to reap the child
176: */
177: if (proxy_command_pid > 1)
1.228 djm 178: kill(proxy_command_pid, SIGHUP);
1.1 deraadt 179: }
180:
1.39 deraadt 181: /*
182: * Creates a (possibly privileged) socket for use as the ssh connection.
183: */
1.109 itojun 184: static int
1.139 markus 185: ssh_create_socket(int privileged, struct addrinfo *ai)
1.1 deraadt 186: {
1.105 markus 187: int sock, gaierr;
188: struct addrinfo hints, *res;
1.1 deraadt 189:
1.40 markus 190: /*
191: * If we are running as root and want to connect to a privileged
192: * port, bind our own socket to a privileged port.
193: */
1.38 markus 194: if (privileged) {
195: int p = IPPORT_RESERVED - 1;
1.124 markus 196: PRIV_START;
1.139 markus 197: sock = rresvport_af(&p, ai->ai_family);
1.124 markus 198: PRIV_END;
1.38 markus 199: if (sock < 0)
1.139 markus 200: error("rresvport: af=%d %.100s", ai->ai_family,
201: strerror(errno));
1.55 markus 202: else
203: debug("Allocated local port %d.", p);
1.105 markus 204: return sock;
205: }
1.217 dtucker 206: sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
1.216 dtucker 207: if (sock < 0) {
1.105 markus 208: error("socket: %.100s", strerror(errno));
1.216 dtucker 209: return -1;
210: }
211: fcntl(sock, F_SETFD, FD_CLOEXEC);
1.105 markus 212:
213: /* Bind the socket to an alternative local IP address */
214: if (options.bind_address == NULL)
215: return sock;
216:
217: memset(&hints, 0, sizeof(hints));
1.139 markus 218: hints.ai_family = ai->ai_family;
219: hints.ai_socktype = ai->ai_socktype;
220: hints.ai_protocol = ai->ai_protocol;
1.105 markus 221: hints.ai_flags = AI_PASSIVE;
1.205 dtucker 222: gaierr = getaddrinfo(options.bind_address, NULL, &hints, &res);
1.105 markus 223: if (gaierr) {
224: error("getaddrinfo: %s: %s", options.bind_address,
1.203 dtucker 225: ssh_gai_strerror(gaierr));
1.105 markus 226: close(sock);
227: return -1;
228: }
229: if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
230: error("bind: %s: %s", options.bind_address, strerror(errno));
231: close(sock);
232: freeaddrinfo(res);
233: return -1;
1.38 markus 234: }
1.105 markus 235: freeaddrinfo(res);
1.38 markus 236: return sock;
1.1 deraadt 237: }
238:
1.141 djm 239: static int
240: timeout_connect(int sockfd, const struct sockaddr *serv_addr,
1.202 djm 241: socklen_t addrlen, int *timeoutp)
1.141 djm 242: {
243: fd_set *fdset;
1.202 djm 244: struct timeval tv, t_start;
1.141 djm 245: socklen_t optlen;
1.179 djm 246: int optval, rc, result = -1;
1.141 djm 247:
1.202 djm 248: gettimeofday(&t_start, NULL);
249:
250: if (*timeoutp <= 0) {
251: result = connect(sockfd, serv_addr, addrlen);
252: goto done;
253: }
1.141 djm 254:
1.156 djm 255: set_nonblock(sockfd);
1.141 djm 256: rc = connect(sockfd, serv_addr, addrlen);
1.156 djm 257: if (rc == 0) {
258: unset_nonblock(sockfd);
1.202 djm 259: result = 0;
260: goto done;
261: }
262: if (errno != EINPROGRESS) {
263: result = -1;
264: goto done;
1.156 djm 265: }
1.141 djm 266:
1.179 djm 267: fdset = (fd_set *)xcalloc(howmany(sockfd + 1, NFDBITS),
268: sizeof(fd_mask));
1.141 djm 269: FD_SET(sockfd, fdset);
1.202 djm 270: ms_to_timeval(&tv, *timeoutp);
1.141 djm 271:
1.162 deraadt 272: for (;;) {
1.141 djm 273: rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
274: if (rc != -1 || errno != EINTR)
275: break;
276: }
277:
1.162 deraadt 278: switch (rc) {
1.141 djm 279: case 0:
280: /* Timed out */
281: errno = ETIMEDOUT;
1.142 djm 282: break;
1.141 djm 283: case -1:
284: /* Select error */
1.154 djm 285: debug("select: %s", strerror(errno));
1.142 djm 286: break;
1.141 djm 287: case 1:
288: /* Completed or failed */
289: optval = 0;
290: optlen = sizeof(optval);
1.154 djm 291: if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval,
1.148 markus 292: &optlen) == -1) {
1.154 djm 293: debug("getsockopt: %s", strerror(errno));
1.142 djm 294: break;
1.148 markus 295: }
1.141 djm 296: if (optval != 0) {
297: errno = optval;
1.142 djm 298: break;
1.141 djm 299: }
1.142 djm 300: result = 0;
1.156 djm 301: unset_nonblock(sockfd);
1.141 djm 302: break;
303: default:
304: /* Should not occur */
305: fatal("Bogus return (%d) from select()", rc);
306: }
307:
1.238 ! djm 308: free(fdset);
1.202 djm 309:
310: done:
311: if (result == 0 && *timeoutp > 0) {
312: ms_subtract_diff(&t_start, timeoutp);
313: if (*timeoutp <= 0) {
314: errno = ETIMEDOUT;
315: result = -1;
316: }
317: }
318:
1.142 djm 319: return (result);
1.141 djm 320: }
321:
1.39 deraadt 322: /*
1.49 markus 323: * Opens a TCP/IP connection to the remote server on the given host.
324: * The address of the remote host will be returned in hostaddr.
1.124 markus 325: * If port is 0, the default port will be used. If needpriv is true,
1.39 deraadt 326: * a privileged port will be allocated to make the connection.
1.124 markus 327: * This requires super-user privileges if needpriv is true.
1.39 deraadt 328: * Connection_attempts specifies the maximum number of tries (one per
329: * second). If proxy_command is non-NULL, it specifies the command (with %h
330: * and %p substituted for host and port, respectively) to use to contact
331: * the daemon.
332: */
1.38 markus 333: int
1.49 markus 334: ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
1.202 djm 335: u_short port, int family, int connection_attempts, int *timeout_ms,
336: int want_keepalive, int needpriv, const char *proxy_command)
1.1 deraadt 337: {
1.90 markus 338: int gaierr;
339: int on = 1;
1.49 markus 340: int sock = -1, attempt;
1.90 markus 341: char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1.49 markus 342: struct addrinfo hints, *ai, *aitop;
1.38 markus 343:
1.136 markus 344: debug2("ssh_connect: needpriv %d", needpriv);
1.38 markus 345:
346: /* If a proxy command is given, connect using it. */
347: if (proxy_command != NULL)
1.124 markus 348: return ssh_proxy_connect(host, port, proxy_command);
1.38 markus 349:
350: /* No proxy command. */
351:
1.49 markus 352: memset(&hints, 0, sizeof(hints));
1.115 markus 353: hints.ai_family = family;
1.49 markus 354: hints.ai_socktype = SOCK_STREAM;
1.126 deraadt 355: snprintf(strport, sizeof strport, "%u", port);
1.49 markus 356: if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
1.203 dtucker 357: fatal("%s: Could not resolve hostname %.100s: %s", __progname,
358: host, ssh_gai_strerror(gaierr));
1.38 markus 359:
1.181 markus 360: for (attempt = 0; attempt < connection_attempts; attempt++) {
1.200 markus 361: if (attempt > 0) {
362: /* Sleep a moment before retrying. */
363: sleep(1);
1.38 markus 364: debug("Trying again...");
1.200 markus 365: }
1.181 markus 366: /*
367: * Loop through addresses for this host, and try each one in
368: * sequence until the connection succeeds.
369: */
1.49 markus 370: for (ai = aitop; ai; ai = ai->ai_next) {
371: if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
372: continue;
373: if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
374: ntop, sizeof(ntop), strport, sizeof(strport),
375: NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
376: error("ssh_connect: getnameinfo failed");
377: continue;
378: }
379: debug("Connecting to %.200s [%.100s] port %s.",
380: host, ntop, strport);
381:
382: /* Create a socket for connecting. */
1.139 markus 383: sock = ssh_create_socket(needpriv, ai);
1.49 markus 384: if (sock < 0)
1.110 markus 385: /* Any error is already output */
1.49 markus 386: continue;
387:
1.141 djm 388: if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
1.202 djm 389: timeout_ms) >= 0) {
1.49 markus 390: /* Successful connection. */
1.102 markus 391: memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
1.38 markus 392: break;
1.49 markus 393: } else {
1.131 itojun 394: debug("connect to address %s port %s: %s",
395: ntop, strport, strerror(errno));
1.38 markus 396: close(sock);
1.181 markus 397: sock = -1;
1.38 markus 398: }
399: }
1.181 markus 400: if (sock != -1)
1.49 markus 401: break; /* Successful connection. */
1.38 markus 402: }
1.49 markus 403:
404: freeaddrinfo(aitop);
405:
1.38 markus 406: /* Return failure if we didn't get a successful connection. */
1.181 markus 407: if (sock == -1) {
1.159 markus 408: error("ssh: connect to host %s port %s: %s",
1.130 itojun 409: host, strport, strerror(errno));
1.159 markus 410: return (-1);
1.130 itojun 411: }
1.38 markus 412:
413: debug("Connection established.");
1.90 markus 414:
1.155 markus 415: /* Set SO_KEEPALIVE if requested. */
1.202 djm 416: if (want_keepalive &&
1.90 markus 417: setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
418: sizeof(on)) < 0)
419: error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1.38 markus 420:
421: /* Set the connection. */
422: packet_set_connection(sock, sock);
1.207 dtucker 423: packet_set_timeout(options.server_alive_interval,
424: options.server_alive_count_max);
1.1 deraadt 425:
1.110 markus 426: return 0;
1.59 markus 427: }
428:
1.235 djm 429: static void
430: send_client_banner(int connection_out, int minor1)
431: {
432: /* Send our own protocol version identification. */
433: if (compat20) {
434: xasprintf(&client_version_string, "SSH-%d.%d-%.100s\r\n",
435: PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, SSH_VERSION);
436: } else {
437: xasprintf(&client_version_string, "SSH-%d.%d-%.100s\n",
438: PROTOCOL_MAJOR_1, minor1, SSH_VERSION);
439: }
440: if (roaming_atomicio(vwrite, connection_out, client_version_string,
441: strlen(client_version_string)) != strlen(client_version_string))
442: fatal("write: %.100s", strerror(errno));
443: chop(client_version_string);
444: debug("Local version string %.100s", client_version_string);
445: }
446:
1.43 markus 447: /*
1.39 deraadt 448: * Waits for the server identification string, and sends our own
449: * identification string.
450: */
1.213 andreas 451: void
1.202 djm 452: ssh_exchange_identification(int timeout_ms)
1.1 deraadt 453: {
1.38 markus 454: char buf[256], remote_version[256]; /* must be same size! */
1.165 djm 455: int remote_major, remote_minor, mismatch;
1.38 markus 456: int connection_in = packet_get_connection_in();
457: int connection_out = packet_get_connection_out();
1.235 djm 458: int minor1 = PROTOCOL_MINOR_1, client_banner_sent = 0;
1.185 djm 459: u_int i, n;
1.202 djm 460: size_t len;
461: int fdsetsz, remaining, rc;
462: struct timeval t_start, t_remaining;
463: fd_set *fdset;
464:
465: fdsetsz = howmany(connection_in + 1, NFDBITS) * sizeof(fd_mask);
466: fdset = xcalloc(1, fdsetsz);
1.38 markus 467:
1.235 djm 468: /*
469: * If we are SSH2-only then we can send the banner immediately and
470: * save a round-trip.
471: */
472: if (options.protocol == SSH_PROTO_2) {
473: enable_compat20();
474: send_client_banner(connection_out, 0);
475: client_banner_sent = 1;
476: }
477:
1.163 avsm 478: /* Read other side's version identification. */
1.202 djm 479: remaining = timeout_ms;
1.185 djm 480: for (n = 0;;) {
1.75 markus 481: for (i = 0; i < sizeof(buf) - 1; i++) {
1.202 djm 482: if (timeout_ms > 0) {
483: gettimeofday(&t_start, NULL);
484: ms_to_timeval(&t_remaining, remaining);
485: FD_SET(connection_in, fdset);
486: rc = select(connection_in + 1, fdset, NULL,
487: fdset, &t_remaining);
488: ms_subtract_diff(&t_start, &remaining);
489: if (rc == 0 || remaining <= 0)
490: fatal("Connection timed out during "
491: "banner exchange");
492: if (rc == -1) {
493: if (errno == EINTR)
494: continue;
495: fatal("ssh_exchange_identification: "
496: "select: %s", strerror(errno));
497: }
498: }
499:
1.214 andreas 500: len = roaming_atomicio(read, connection_in, &buf[i], 1);
1.163 avsm 501:
1.167 djm 502: if (len != 1 && errno == EPIPE)
1.202 djm 503: fatal("ssh_exchange_identification: "
504: "Connection closed by remote host");
1.163 avsm 505: else if (len != 1)
1.202 djm 506: fatal("ssh_exchange_identification: "
507: "read: %.100s", strerror(errno));
1.75 markus 508: if (buf[i] == '\r') {
509: buf[i] = '\n';
510: buf[i + 1] = 0;
511: continue; /**XXX wait for \n */
512: }
513: if (buf[i] == '\n') {
514: buf[i + 1] = 0;
515: break;
516: }
1.185 djm 517: if (++n > 65536)
1.202 djm 518: fatal("ssh_exchange_identification: "
519: "No banner received");
1.38 markus 520: }
1.75 markus 521: buf[sizeof(buf) - 1] = 0;
1.76 markus 522: if (strncmp(buf, "SSH-", 4) == 0)
1.38 markus 523: break;
1.75 markus 524: debug("ssh_exchange_identification: %s", buf);
1.38 markus 525: }
1.59 markus 526: server_version_string = xstrdup(buf);
1.238 ! djm 527: free(fdset);
1.38 markus 528:
1.40 markus 529: /*
530: * Check that the versions match. In future this might accept
531: * several versions and set appropriate flags to handle them.
532: */
1.59 markus 533: if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
534: &remote_major, &remote_minor, remote_version) != 3)
1.38 markus 535: fatal("Bad remote protocol version identification: '%.100s'", buf);
536: debug("Remote protocol version %d.%d, remote software version %.100s",
1.118 deraadt 537: remote_major, remote_minor, remote_version);
1.38 markus 538:
1.59 markus 539: compat_datafellows(remote_version);
1.64 markus 540: mismatch = 0;
1.59 markus 541:
1.116 deraadt 542: switch (remote_major) {
1.64 markus 543: case 1:
544: if (remote_minor == 99 &&
545: (options.protocol & SSH_PROTO_2) &&
546: !(options.protocol & SSH_PROTO_1_PREFERRED)) {
547: enable_compat20();
548: break;
549: }
550: if (!(options.protocol & SSH_PROTO_1)) {
551: mismatch = 1;
552: break;
553: }
554: if (remote_minor < 3) {
555: fatal("Remote machine has too old SSH software version.");
1.81 markus 556: } else if (remote_minor == 3 || remote_minor == 4) {
1.64 markus 557: /* We speak 1.3, too. */
558: enable_compat13();
1.81 markus 559: minor1 = 3;
1.64 markus 560: if (options.forward_agent) {
1.138 itojun 561: logit("Agent forwarding disabled for protocol 1.3");
1.64 markus 562: options.forward_agent = 0;
563: }
564: }
565: break;
566: case 2:
567: if (options.protocol & SSH_PROTO_2) {
568: enable_compat20();
569: break;
1.38 markus 570: }
1.64 markus 571: /* FALLTHROUGH */
1.68 markus 572: default:
1.64 markus 573: mismatch = 1;
574: break;
1.38 markus 575: }
1.64 markus 576: if (mismatch)
1.38 markus 577: fatal("Protocol major versions differ: %d vs. %d",
1.64 markus 578: (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
579: remote_major);
1.235 djm 580: if (!client_banner_sent)
581: send_client_banner(connection_out, minor1);
1.59 markus 582: chop(server_version_string);
1.1 deraadt 583: }
584:
1.96 markus 585: /* defaults to 'no' */
1.109 itojun 586: static int
1.112 markus 587: confirm(const char *prompt)
1.1 deraadt 588: {
1.119 markus 589: const char *msg, *again = "Please type 'yes' or 'no': ";
590: char *p;
591: int ret = -1;
1.96 markus 592:
593: if (options.batch_mode)
594: return 0;
1.119 markus 595: for (msg = prompt;;msg = again) {
596: p = read_passphrase(msg, RP_ECHO);
597: if (p == NULL ||
598: (p[0] == '\0') || (p[0] == '\n') ||
599: strncasecmp(p, "no", 2) == 0)
600: ret = 0;
1.127 markus 601: if (p && strncasecmp(p, "yes", 3) == 0)
1.119 markus 602: ret = 1;
1.238 ! djm 603: free(p);
1.119 markus 604: if (ret != -1)
605: return ret;
1.1 deraadt 606: }
607: }
608:
1.219 djm 609: static int
610: check_host_cert(const char *host, const Key *host_key)
611: {
612: const char *reason;
613:
614: if (key_cert_check_authority(host_key, 1, 0, host, &reason) != 0) {
615: error("%s", reason);
616: return 0;
617: }
1.223 djm 618: if (buffer_len(&host_key->cert->critical) != 0) {
619: error("Certificate for %s contains unsupported "
620: "critical options(s)", host);
1.219 djm 621: return 0;
622: }
623: return 1;
624: }
625:
1.229 djm 626: static int
627: sockaddr_is_local(struct sockaddr *hostaddr)
628: {
629: switch (hostaddr->sa_family) {
630: case AF_INET:
631: return (ntohl(((struct sockaddr_in *)hostaddr)->
632: sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
633: case AF_INET6:
634: return IN6_IS_ADDR_LOOPBACK(
635: &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
636: default:
637: return 0;
638: }
639: }
640:
641: /*
642: * Prepare the hostname and ip address strings that are used to lookup
643: * host keys in known_hosts files. These may have a port number appended.
644: */
645: void
646: get_hostfile_hostname_ipaddr(char *hostname, struct sockaddr *hostaddr,
647: u_short port, char **hostfile_hostname, char **hostfile_ipaddr)
648: {
649: char ntop[NI_MAXHOST];
650:
651: /*
652: * We don't have the remote ip-address for connections
653: * using a proxy command
654: */
655: if (hostfile_ipaddr != NULL) {
656: if (options.proxy_command == NULL) {
657: if (getnameinfo(hostaddr, hostaddr->sa_len,
658: ntop, sizeof(ntop), NULL, 0, NI_NUMERICHOST) != 0)
659: fatal("check_host_key: getnameinfo failed");
660: *hostfile_ipaddr = put_host_port(ntop, port);
661: } else {
662: *hostfile_ipaddr = xstrdup("<no hostip for proxy "
663: "command>");
664: }
665: }
666:
667: /*
668: * Allow the user to record the key under a different name or
669: * differentiate a non-standard port. This is useful for ssh
670: * tunneling over forwarded connections or if you run multiple
671: * sshd's on different ports on the same machine.
672: */
673: if (hostfile_hostname != NULL) {
674: if (options.host_key_alias != NULL) {
675: *hostfile_hostname = xstrdup(options.host_key_alias);
676: debug("using hostkeyalias: %s", *hostfile_hostname);
677: } else {
678: *hostfile_hostname = put_host_port(hostname, port);
679: }
680: }
681: }
682:
1.39 deraadt 683: /*
1.108 markus 684: * check whether the supplied host key is valid, return -1 if the key
1.234 djm 685: * is not valid. user_hostfile[0] will not be updated if 'readonly' is true.
1.39 deraadt 686: */
1.197 dtucker 687: #define RDRW 0
688: #define RDONLY 1
689: #define ROQUIET 2
1.109 itojun 690: static int
1.197 dtucker 691: check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port,
1.234 djm 692: Key *host_key, int readonly,
693: char **user_hostfiles, u_int num_user_hostfiles,
694: char **system_hostfiles, u_int num_system_hostfiles)
1.1 deraadt 695: {
1.234 djm 696: HostStatus host_status;
697: HostStatus ip_status;
1.229 djm 698: Key *raw_key = NULL;
1.189 dtucker 699: char *ip = NULL, *host = NULL;
1.204 grunk 700: char hostline[1000], *hostp, *fp, *ra;
1.119 markus 701: char msg[1024];
1.234 djm 702: const char *type;
703: const struct hostkey_entry *host_found, *ip_found;
1.229 djm 704: int len, cancelled_forwarding = 0;
1.234 djm 705: int local = sockaddr_is_local(hostaddr);
706: int r, want_cert = key_is_cert(host_key), host_ip_differ = 0;
1.229 djm 707: struct hostkeys *host_hostkeys, *ip_hostkeys;
1.234 djm 708: u_int i;
1.49 markus 709:
710: /*
711: * Force accepting of the host key for loopback/localhost. The
712: * problem is that if the home directory is NFS-mounted to multiple
713: * machines, localhost will refer to a different machine in each of
714: * them, and the user will get bogus HOST_CHANGED warnings. This
715: * essentially disables host authentication for localhost; however,
716: * this is probably not a real problem.
717: */
1.111 markus 718: if (options.no_host_authentication_for_localhost == 1 && local &&
719: options.host_key_alias == NULL) {
1.88 markus 720: debug("Forcing accepting of host key for "
721: "loopback/localhost.");
1.108 markus 722: return 0;
1.49 markus 723: }
1.42 markus 724:
725: /*
1.229 djm 726: * Prepare the hostname and address strings used for hostkey lookup.
727: * In some cases, these will have a port number appended.
1.42 markus 728: */
1.229 djm 729: get_hostfile_hostname_ipaddr(hostname, hostaddr, port, &host, &ip);
1.206 grunk 730:
731: /*
1.88 markus 732: * Turn off check_host_ip if the connection is to localhost, via proxy
733: * command or if we don't have a hostname to compare with
734: */
1.189 dtucker 735: if (options.check_host_ip && (local ||
736: strcmp(hostname, ip) == 0 || options.proxy_command != NULL))
1.88 markus 737: options.check_host_ip = 0;
1.86 markus 738:
1.229 djm 739: host_hostkeys = init_hostkeys();
1.234 djm 740: for (i = 0; i < num_user_hostfiles; i++)
741: load_hostkeys(host_hostkeys, host, user_hostfiles[i]);
742: for (i = 0; i < num_system_hostfiles; i++)
743: load_hostkeys(host_hostkeys, host, system_hostfiles[i]);
1.229 djm 744:
745: ip_hostkeys = NULL;
746: if (!want_cert && options.check_host_ip) {
747: ip_hostkeys = init_hostkeys();
1.234 djm 748: for (i = 0; i < num_user_hostfiles; i++)
749: load_hostkeys(ip_hostkeys, ip, user_hostfiles[i]);
750: for (i = 0; i < num_system_hostfiles; i++)
751: load_hostkeys(ip_hostkeys, ip, system_hostfiles[i]);
1.84 markus 752: }
1.38 markus 753:
1.219 djm 754: retry:
1.229 djm 755: /* Reload these as they may have changed on cert->key downgrade */
1.219 djm 756: want_cert = key_is_cert(host_key);
757: type = key_type(host_key);
758:
1.46 markus 759: /*
1.170 djm 760: * Check if the host key is present in the user's list of known
1.40 markus 761: * hosts or in the systemwide list.
762: */
1.229 djm 763: host_status = check_key_in_hostkeys(host_hostkeys, host_key,
764: &host_found);
765:
1.40 markus 766: /*
767: * Also perform check for the ip address, skip the check if we are
1.219 djm 768: * localhost, looking for a certificate, or the hostname was an ip
769: * address to begin with.
1.40 markus 770: */
1.229 djm 771: if (!want_cert && ip_hostkeys != NULL) {
772: ip_status = check_key_in_hostkeys(ip_hostkeys, host_key,
773: &ip_found);
1.38 markus 774: if (host_status == HOST_CHANGED &&
1.229 djm 775: (ip_status != HOST_CHANGED ||
776: (ip_found != NULL &&
777: !key_equal(ip_found->key, host_found->key))))
1.38 markus 778: host_ip_differ = 1;
779: } else
780: ip_status = host_status;
781:
782: switch (host_status) {
783: case HOST_OK:
784: /* The host is known and the key matches. */
1.219 djm 785: debug("Host '%.200s' is known and matches the %s host %s.",
786: host, type, want_cert ? "certificate" : "key");
1.229 djm 787: debug("Found %s in %s:%lu", want_cert ? "CA key" : "key",
788: host_found->file, host_found->line);
1.219 djm 789: if (want_cert && !check_host_cert(hostname, host_key))
790: goto fail;
1.88 markus 791: if (options.check_host_ip && ip_status == HOST_NEW) {
1.219 djm 792: if (readonly || want_cert)
1.138 itojun 793: logit("%s host key for IP address "
1.108 markus 794: "'%.128s' not in list of known hosts.",
795: type, ip);
1.234 djm 796: else if (!add_host_to_hostfile(user_hostfiles[0], ip,
1.160 djm 797: host_key, options.hash_known_hosts))
1.138 itojun 798: logit("Failed to add the %s host key for IP "
1.108 markus 799: "address '%.128s' to the list of known "
1.234 djm 800: "hosts (%.30s).", type, ip,
801: user_hostfiles[0]);
1.88 markus 802: else
1.138 itojun 803: logit("Warning: Permanently added the %s host "
1.108 markus 804: "key for IP address '%.128s' to the list "
805: "of known hosts.", type, ip);
1.209 grunk 806: } else if (options.visual_host_key) {
1.204 grunk 807: fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
808: ra = key_fingerprint(host_key, SSH_FP_MD5,
809: SSH_FP_RANDOMART);
810: logit("Host key fingerprint is %s\n%s\n", fp, ra);
1.238 ! djm 811: free(ra);
! 812: free(fp);
1.38 markus 813: }
814: break;
815: case HOST_NEW:
1.197 dtucker 816: if (options.host_key_alias == NULL && port != 0 &&
817: port != SSH_DEFAULT_PORT) {
818: debug("checking without port identifier");
1.212 stevesk 819: if (check_host_key(hostname, hostaddr, 0, host_key,
1.234 djm 820: ROQUIET, user_hostfiles, num_user_hostfiles,
821: system_hostfiles, num_system_hostfiles) == 0) {
1.197 dtucker 822: debug("found matching key w/out port");
823: break;
824: }
825: }
1.219 djm 826: if (readonly || want_cert)
1.108 markus 827: goto fail;
1.38 markus 828: /* The host is new. */
829: if (options.strict_host_key_checking == 1) {
1.108 markus 830: /*
831: * User has requested strict host key checking. We
832: * will not add the host key automatically. The only
833: * alternative left is to abort.
834: */
835: error("No %s host key is known for %.200s and you "
836: "have requested strict checking.", type, host);
837: goto fail;
1.38 markus 838: } else if (options.strict_host_key_checking == 2) {
1.145 jakob 839: char msg1[1024], msg2[1024];
840:
1.229 djm 841: if (show_other_keys(host_hostkeys, host_key))
1.145 jakob 842: snprintf(msg1, sizeof(msg1),
1.168 djm 843: "\nbut keys of different type are already"
844: " known for this host.");
1.145 jakob 845: else
846: snprintf(msg1, sizeof(msg1), ".");
1.38 markus 847: /* The default */
1.100 markus 848: fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1.204 grunk 849: ra = key_fingerprint(host_key, SSH_FP_MD5,
850: SSH_FP_RANDOMART);
1.145 jakob 851: msg2[0] = '\0';
852: if (options.verify_host_key_dns) {
1.153 jakob 853: if (matching_host_key_dns)
1.145 jakob 854: snprintf(msg2, sizeof(msg2),
855: "Matching host key fingerprint"
856: " found in DNS.\n");
857: else
858: snprintf(msg2, sizeof(msg2),
859: "No matching host key fingerprint"
860: " found in DNS.\n");
861: }
1.119 markus 862: snprintf(msg, sizeof(msg),
1.108 markus 863: "The authenticity of host '%.200s (%s)' can't be "
1.132 markus 864: "established%s\n"
1.209 grunk 865: "%s key fingerprint is %s.%s%s\n%s"
1.108 markus 866: "Are you sure you want to continue connecting "
1.132 markus 867: "(yes/no)? ",
1.209 grunk 868: host, ip, msg1, type, fp,
869: options.visual_host_key ? "\n" : "",
870: options.visual_host_key ? ra : "",
871: msg2);
1.238 ! djm 872: free(ra);
! 873: free(fp);
1.119 markus 874: if (!confirm(msg))
1.108 markus 875: goto fail;
1.38 markus 876: }
1.161 djm 877: /*
878: * If not in strict mode, add the key automatically to the
879: * local known_hosts file.
880: */
1.88 markus 881: if (options.check_host_ip && ip_status == HOST_NEW) {
1.229 djm 882: snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
1.38 markus 883: hostp = hostline;
1.161 djm 884: if (options.hash_known_hosts) {
885: /* Add hash of host and IP separately */
1.234 djm 886: r = add_host_to_hostfile(user_hostfiles[0],
887: host, host_key, options.hash_known_hosts) &&
888: add_host_to_hostfile(user_hostfiles[0], ip,
1.161 djm 889: host_key, options.hash_known_hosts);
890: } else {
891: /* Add unhashed "host,ip" */
1.234 djm 892: r = add_host_to_hostfile(user_hostfiles[0],
1.161 djm 893: hostline, host_key,
894: options.hash_known_hosts);
895: }
896: } else {
1.234 djm 897: r = add_host_to_hostfile(user_hostfiles[0], host,
898: host_key, options.hash_known_hosts);
1.38 markus 899: hostp = host;
1.161 djm 900: }
1.38 markus 901:
1.161 djm 902: if (!r)
1.138 itojun 903: logit("Failed to add the host to the list of known "
1.234 djm 904: "hosts (%.500s).", user_hostfiles[0]);
1.38 markus 905: else
1.138 itojun 906: logit("Warning: Permanently added '%.200s' (%s) to the "
1.108 markus 907: "list of known hosts.", hostp, type);
1.38 markus 908: break;
1.220 djm 909: case HOST_REVOKED:
910: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
911: error("@ WARNING: REVOKED HOST KEY DETECTED! @");
912: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
913: error("The %s host key for %s is marked as revoked.", type, host);
914: error("This could mean that a stolen key is being used to");
915: error("impersonate this host.");
916:
917: /*
918: * If strict host key checking is in use, the user will have
919: * to edit the key manually and we can only abort.
920: */
921: if (options.strict_host_key_checking) {
922: error("%s host key for %.200s was revoked and you have "
923: "requested strict checking.", type, host);
924: goto fail;
925: }
926: goto continue_unsafe;
927:
1.38 markus 928: case HOST_CHANGED:
1.219 djm 929: if (want_cert) {
930: /*
931: * This is only a debug() since it is valid to have
932: * CAs with wildcard DNS matches that don't match
933: * all hosts that one might visit.
934: */
935: debug("Host certificate authority does not "
1.229 djm 936: "match %s in %s:%lu", CA_MARKER,
937: host_found->file, host_found->line);
1.219 djm 938: goto fail;
939: }
1.197 dtucker 940: if (readonly == ROQUIET)
941: goto fail;
1.38 markus 942: if (options.check_host_ip && host_ip_differ) {
1.158 avsm 943: char *key_msg;
1.38 markus 944: if (ip_status == HOST_NEW)
1.158 avsm 945: key_msg = "is unknown";
1.38 markus 946: else if (ip_status == HOST_OK)
1.158 avsm 947: key_msg = "is unchanged";
1.38 markus 948: else
1.158 avsm 949: key_msg = "has a different value";
1.38 markus 950: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
951: error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
952: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1.72 markus 953: error("The %s host key for %s has changed,", type, host);
1.208 ian 954: error("and the key for the corresponding IP address %s", ip);
1.158 avsm 955: error("%s. This could either mean that", key_msg);
1.38 markus 956: error("DNS SPOOFING is happening or the IP address for the host");
1.85 markus 957: error("and its host key have changed at the same time.");
1.88 markus 958: if (ip_status != HOST_NEW)
1.229 djm 959: error("Offending key for IP in %s:%lu",
960: ip_found->file, ip_found->line);
1.38 markus 961: }
962: /* The host key has changed. */
1.150 jakob 963: warn_changed_key(host_key);
1.38 markus 964: error("Add correct host key in %.100s to get rid of this message.",
1.234 djm 965: user_hostfiles[0]);
1.229 djm 966: error("Offending %s key in %s:%lu", key_type(host_found->key),
967: host_found->file, host_found->line);
1.38 markus 968:
1.40 markus 969: /*
970: * If strict host key checking is in use, the user will have
971: * to edit the key manually and we can only abort.
972: */
1.108 markus 973: if (options.strict_host_key_checking) {
974: error("%s host key for %.200s has changed and you have "
975: "requested strict checking.", type, host);
976: goto fail;
977: }
1.38 markus 978:
1.220 djm 979: continue_unsafe:
1.40 markus 980: /*
981: * If strict host key checking has not been requested, allow
1.144 djm 982: * the connection but without MITM-able authentication or
1.194 stevesk 983: * forwarding.
1.40 markus 984: */
1.38 markus 985: if (options.password_authentication) {
1.108 markus 986: error("Password authentication is disabled to avoid "
987: "man-in-the-middle attacks.");
1.38 markus 988: options.password_authentication = 0;
1.210 dtucker 989: cancelled_forwarding = 1;
1.144 djm 990: }
991: if (options.kbd_interactive_authentication) {
992: error("Keyboard-interactive authentication is disabled"
993: " to avoid man-in-the-middle attacks.");
994: options.kbd_interactive_authentication = 0;
995: options.challenge_response_authentication = 0;
1.210 dtucker 996: cancelled_forwarding = 1;
1.144 djm 997: }
998: if (options.challenge_response_authentication) {
999: error("Challenge/response authentication is disabled"
1000: " to avoid man-in-the-middle attacks.");
1001: options.challenge_response_authentication = 0;
1.210 dtucker 1002: cancelled_forwarding = 1;
1.38 markus 1003: }
1004: if (options.forward_agent) {
1.108 markus 1005: error("Agent forwarding is disabled to avoid "
1006: "man-in-the-middle attacks.");
1.38 markus 1007: options.forward_agent = 0;
1.210 dtucker 1008: cancelled_forwarding = 1;
1.83 markus 1009: }
1010: if (options.forward_x11) {
1.108 markus 1011: error("X11 forwarding is disabled to avoid "
1012: "man-in-the-middle attacks.");
1.83 markus 1013: options.forward_x11 = 0;
1.210 dtucker 1014: cancelled_forwarding = 1;
1.83 markus 1015: }
1.108 markus 1016: if (options.num_local_forwards > 0 ||
1017: options.num_remote_forwards > 0) {
1018: error("Port forwarding is disabled to avoid "
1019: "man-in-the-middle attacks.");
1020: options.num_local_forwards =
1.118 deraadt 1021: options.num_remote_forwards = 0;
1.210 dtucker 1022: cancelled_forwarding = 1;
1.194 stevesk 1023: }
1024: if (options.tun_open != SSH_TUNMODE_NO) {
1025: error("Tunnel forwarding is disabled to avoid "
1026: "man-in-the-middle attacks.");
1027: options.tun_open = SSH_TUNMODE_NO;
1.210 dtucker 1028: cancelled_forwarding = 1;
1.38 markus 1029: }
1.210 dtucker 1030: if (options.exit_on_forward_failure && cancelled_forwarding)
1031: fatal("Error: forwarding disabled due to host key "
1032: "check failure");
1033:
1.40 markus 1034: /*
1035: * XXX Should permit the user to change to use the new id.
1036: * This could be done by converting the host key to an
1037: * identifying sentence, tell that the host identifies itself
1.218 dtucker 1038: * by that sentence, and ask the user if he/she wishes to
1.40 markus 1039: * accept the authentication.
1040: */
1.38 markus 1041: break;
1.132 markus 1042: case HOST_FOUND:
1043: fatal("internal error");
1044: break;
1.88 markus 1045: }
1046:
1047: if (options.check_host_ip && host_status != HOST_CHANGED &&
1048: ip_status == HOST_CHANGED) {
1.119 markus 1049: snprintf(msg, sizeof(msg),
1050: "Warning: the %s host key for '%.200s' "
1051: "differs from the key for the IP address '%.128s'"
1.229 djm 1052: "\nOffending key for IP in %s:%lu",
1053: type, host, ip, ip_found->file, ip_found->line);
1.119 markus 1054: if (host_status == HOST_OK) {
1055: len = strlen(msg);
1056: snprintf(msg + len, sizeof(msg) - len,
1.229 djm 1057: "\nMatching host key in %s:%lu",
1058: host_found->file, host_found->line);
1.119 markus 1059: }
1.88 markus 1060: if (options.strict_host_key_checking == 1) {
1.143 djm 1061: logit("%s", msg);
1.108 markus 1062: error("Exiting, you have requested strict checking.");
1063: goto fail;
1.88 markus 1064: } else if (options.strict_host_key_checking == 2) {
1.119 markus 1065: strlcat(msg, "\nAre you sure you want "
1066: "to continue connecting (yes/no)? ", sizeof(msg));
1067: if (!confirm(msg))
1.108 markus 1068: goto fail;
1.119 markus 1069: } else {
1.143 djm 1070: logit("%s", msg);
1.88 markus 1071: }
1.38 markus 1072: }
1.82 provos 1073:
1.238 ! djm 1074: free(ip);
! 1075: free(host);
1.229 djm 1076: if (host_hostkeys != NULL)
1077: free_hostkeys(host_hostkeys);
1078: if (ip_hostkeys != NULL)
1079: free_hostkeys(ip_hostkeys);
1.108 markus 1080: return 0;
1081:
1082: fail:
1.220 djm 1083: if (want_cert && host_status != HOST_REVOKED) {
1.219 djm 1084: /*
1085: * No matching certificate. Downgrade cert to raw key and
1086: * search normally.
1087: */
1088: debug("No matching CA found. Retry with plain key");
1089: raw_key = key_from_private(host_key);
1090: if (key_drop_cert(raw_key) != 0)
1091: fatal("Couldn't drop certificate");
1092: host_key = raw_key;
1093: goto retry;
1094: }
1095: if (raw_key != NULL)
1096: key_free(raw_key);
1.238 ! djm 1097: free(ip);
! 1098: free(host);
1.229 djm 1099: if (host_hostkeys != NULL)
1100: free_hostkeys(host_hostkeys);
1101: if (ip_hostkeys != NULL)
1102: free_hostkeys(ip_hostkeys);
1.108 markus 1103: return -1;
1104: }
1105:
1.140 jakob 1106: /* returns 0 if key verifies or -1 if key does NOT verify */
1.108 markus 1107: int
1108: verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
1109: {
1.153 jakob 1110: int flags = 0;
1.229 djm 1111: char *fp;
1112:
1113: fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1114: debug("Server host key: %s %s", key_type(host_key), fp);
1.238 ! djm 1115: free(fp);
1.140 jakob 1116:
1.219 djm 1117: /* XXX certs are not yet supported for DNS */
1118: if (!key_is_cert(host_key) && options.verify_host_key_dns &&
1.153 jakob 1119: verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
1120: if (flags & DNS_VERIFY_FOUND) {
1121:
1122: if (options.verify_host_key_dns == 1 &&
1123: flags & DNS_VERIFY_MATCH &&
1124: flags & DNS_VERIFY_SECURE)
1125: return 0;
1126:
1127: if (flags & DNS_VERIFY_MATCH) {
1128: matching_host_key_dns = 1;
1129: } else {
1130: warn_changed_key(host_key);
1131: error("Update the SSHFP RR in DNS with the new "
1132: "host key to get rid of this message.");
1133: }
1.140 jakob 1134: }
1135: }
1.108 markus 1136:
1.234 djm 1137: return check_host_key(host, hostaddr, options.port, host_key, RDRW,
1138: options.user_hostfiles, options.num_user_hostfiles,
1139: options.system_hostfiles, options.num_system_hostfiles);
1.51 markus 1140: }
1.70 markus 1141:
1.51 markus 1142: /*
1143: * Starts a dialog with the server, and authenticates the current user on the
1144: * server. This does not need any extra privileges. The basic connection
1145: * to the server must already have been established before this is called.
1146: * If login fails, this function prints an error and never returns.
1147: * This function does not require super-user privileges.
1148: */
1149: void
1.120 markus 1150: ssh_login(Sensitive *sensitive, const char *orighost,
1.229 djm 1151: struct sockaddr *hostaddr, u_short port, struct passwd *pw, int timeout_ms)
1.51 markus 1152: {
1153: char *host, *cp;
1.70 markus 1154: char *server_user, *local_user;
1155:
1156: local_user = xstrdup(pw->pw_name);
1157: server_user = options.user ? options.user : local_user;
1.51 markus 1158:
1159: /* Convert the user-supplied hostname into all lowercase. */
1160: host = xstrdup(orighost);
1161: for (cp = host; *cp; cp++)
1162: if (isupper(*cp))
1.178 deraadt 1163: *cp = (char)tolower(*cp);
1.51 markus 1164:
1165: /* Exchange protocol version identification strings with the server. */
1.202 djm 1166: ssh_exchange_identification(timeout_ms);
1.51 markus 1167:
1168: /* Put the connection into non-blocking mode. */
1169: packet_set_nonblocking();
1170:
1171: /* key exchange */
1172: /* authenticate user */
1.59 markus 1173: if (compat20) {
1.229 djm 1174: ssh_kex2(host, hostaddr, port);
1.120 markus 1175: ssh_userauth2(local_user, server_user, host, sensitive);
1.59 markus 1176: } else {
1177: ssh_kex(host, hostaddr);
1.120 markus 1178: ssh_userauth1(local_user, server_user, host, sensitive);
1.59 markus 1179: }
1.238 ! djm 1180: free(local_user);
1.97 markus 1181: }
1182:
1183: void
1184: ssh_put_password(char *password)
1185: {
1186: int size;
1187: char *padded;
1188:
1.99 deraadt 1189: if (datafellows & SSH_BUG_PASSWORDPAD) {
1.107 markus 1190: packet_put_cstring(password);
1.99 deraadt 1191: return;
1192: }
1.97 markus 1193: size = roundup(strlen(password) + 1, 32);
1.179 djm 1194: padded = xcalloc(1, size);
1.97 markus 1195: strlcpy(padded, password, size);
1196: packet_put_string(padded, size);
1197: memset(padded, 0, size);
1.238 ! djm 1198: free(padded);
1.132 markus 1199: }
1200:
1201: /* print all known host keys for a given host, but skip keys of given type */
1202: static int
1.229 djm 1203: show_other_keys(struct hostkeys *hostkeys, Key *key)
1.132 markus 1204: {
1.225 djm 1205: int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, KEY_ECDSA, -1};
1.229 djm 1206: int i, ret = 0;
1207: char *fp, *ra;
1208: const struct hostkey_entry *found;
1.132 markus 1209:
1210: for (i = 0; type[i] != -1; i++) {
1211: if (type[i] == key->type)
1212: continue;
1.229 djm 1213: if (!lookup_key_in_hostkeys_by_type(hostkeys, type[i], &found))
1.132 markus 1214: continue;
1.229 djm 1215: fp = key_fingerprint(found->key, SSH_FP_MD5, SSH_FP_HEX);
1216: ra = key_fingerprint(found->key, SSH_FP_MD5, SSH_FP_RANDOMART);
1217: logit("WARNING: %s key found for host %s\n"
1218: "in %s:%lu\n"
1219: "%s key fingerprint %s.",
1220: key_type(found->key),
1221: found->host, found->file, found->line,
1222: key_type(found->key), fp);
1223: if (options.visual_host_key)
1224: logit("%s", ra);
1.238 ! djm 1225: free(ra);
! 1226: free(fp);
1.229 djm 1227: ret = 1;
1.132 markus 1228: }
1.229 djm 1229: return ret;
1.150 jakob 1230: }
1231:
1232: static void
1233: warn_changed_key(Key *host_key)
1234: {
1235: char *fp;
1236:
1237: fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1238:
1239: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1240: error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
1241: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1242: error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
1243: error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
1.230 markus 1244: error("It is also possible that a host key has just been changed.");
1.150 jakob 1245: error("The fingerprint for the %s key sent by the remote host is\n%s.",
1.230 markus 1246: key_type(host_key), fp);
1.150 jakob 1247: error("Please contact your system administrator.");
1248:
1.238 ! djm 1249: free(fp);
1.171 reyk 1250: }
1251:
1252: /*
1253: * Execute a local command
1254: */
1255: int
1256: ssh_local_cmd(const char *args)
1257: {
1258: char *shell;
1259: pid_t pid;
1260: int status;
1.231 djm 1261: void (*osighand)(int);
1.171 reyk 1262:
1263: if (!options.permit_local_command ||
1264: args == NULL || !*args)
1265: return (1);
1266:
1.226 djm 1267: if ((shell = getenv("SHELL")) == NULL || *shell == '\0')
1.171 reyk 1268: shell = _PATH_BSHELL;
1269:
1.231 djm 1270: osighand = signal(SIGCHLD, SIG_DFL);
1.171 reyk 1271: pid = fork();
1272: if (pid == 0) {
1.232 djm 1273: signal(SIGPIPE, SIG_DFL);
1.171 reyk 1274: debug3("Executing %s -c \"%s\"", shell, args);
1275: execl(shell, shell, "-c", args, (char *)NULL);
1276: error("Couldn't execute %s -c \"%s\": %s",
1277: shell, args, strerror(errno));
1278: _exit(1);
1279: } else if (pid == -1)
1280: fatal("fork failed: %.100s", strerror(errno));
1281: while (waitpid(pid, &status, 0) == -1)
1282: if (errno != EINTR)
1283: fatal("Couldn't wait for child: %s", strerror(errno));
1.231 djm 1284: signal(SIGCHLD, osighand);
1.171 reyk 1285:
1286: if (!WIFEXITED(status))
1287: return (1);
1288:
1289: return (WEXITSTATUS(status));
1.1 deraadt 1290: }
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