Annotation of src/usr.bin/ssh/sshconnect.c, Revision 1.230
1.230 ! markus 1: /* $OpenBSD: sshconnect.c,v 1.229 2010/11/29 23:45:51 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. */
1.89 markus 136: execv(argv[0], argv);
137: perror(argv[0]);
1.38 markus 138: exit(1);
139: }
140: /* Parent. */
141: if (pid < 0)
142: fatal("fork failed: %.100s", strerror(errno));
1.135 djm 143: else
144: proxy_command_pid = pid; /* save pid to clean up later */
1.38 markus 145:
146: /* Close child side of the descriptors. */
147: close(pin[0]);
148: close(pout[1]);
149:
150: /* Free the command name. */
1.164 djm 151: xfree(command_string);
1.38 markus 152:
153: /* Set the connection file descriptors. */
154: packet_set_connection(pout[0], pin[1]);
1.207 dtucker 155: packet_set_timeout(options.server_alive_interval,
156: options.server_alive_count_max);
1.1 deraadt 157:
1.110 markus 158: /* Indicate OK return */
159: return 0;
1.227 djm 160: }
161:
162: void
163: ssh_kill_proxy_command(void)
164: {
165: /*
166: * Send SIGHUP to proxy command if used. We don't wait() in
167: * case it hangs and instead rely on init to reap the child
168: */
169: if (proxy_command_pid > 1)
1.228 djm 170: kill(proxy_command_pid, SIGHUP);
1.1 deraadt 171: }
172:
1.39 deraadt 173: /*
174: * Creates a (possibly privileged) socket for use as the ssh connection.
175: */
1.109 itojun 176: static int
1.139 markus 177: ssh_create_socket(int privileged, struct addrinfo *ai)
1.1 deraadt 178: {
1.105 markus 179: int sock, gaierr;
180: struct addrinfo hints, *res;
1.1 deraadt 181:
1.40 markus 182: /*
183: * If we are running as root and want to connect to a privileged
184: * port, bind our own socket to a privileged port.
185: */
1.38 markus 186: if (privileged) {
187: int p = IPPORT_RESERVED - 1;
1.124 markus 188: PRIV_START;
1.139 markus 189: sock = rresvport_af(&p, ai->ai_family);
1.124 markus 190: PRIV_END;
1.38 markus 191: if (sock < 0)
1.139 markus 192: error("rresvport: af=%d %.100s", ai->ai_family,
193: strerror(errno));
1.55 markus 194: else
195: debug("Allocated local port %d.", p);
1.105 markus 196: return sock;
197: }
1.217 dtucker 198: sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
1.216 dtucker 199: if (sock < 0) {
1.105 markus 200: error("socket: %.100s", strerror(errno));
1.216 dtucker 201: return -1;
202: }
203: fcntl(sock, F_SETFD, FD_CLOEXEC);
1.105 markus 204:
205: /* Bind the socket to an alternative local IP address */
206: if (options.bind_address == NULL)
207: return sock;
208:
209: memset(&hints, 0, sizeof(hints));
1.139 markus 210: hints.ai_family = ai->ai_family;
211: hints.ai_socktype = ai->ai_socktype;
212: hints.ai_protocol = ai->ai_protocol;
1.105 markus 213: hints.ai_flags = AI_PASSIVE;
1.205 dtucker 214: gaierr = getaddrinfo(options.bind_address, NULL, &hints, &res);
1.105 markus 215: if (gaierr) {
216: error("getaddrinfo: %s: %s", options.bind_address,
1.203 dtucker 217: ssh_gai_strerror(gaierr));
1.105 markus 218: close(sock);
219: return -1;
220: }
221: if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
222: error("bind: %s: %s", options.bind_address, strerror(errno));
223: close(sock);
224: freeaddrinfo(res);
225: return -1;
1.38 markus 226: }
1.105 markus 227: freeaddrinfo(res);
1.38 markus 228: return sock;
1.1 deraadt 229: }
230:
1.141 djm 231: static int
232: timeout_connect(int sockfd, const struct sockaddr *serv_addr,
1.202 djm 233: socklen_t addrlen, int *timeoutp)
1.141 djm 234: {
235: fd_set *fdset;
1.202 djm 236: struct timeval tv, t_start;
1.141 djm 237: socklen_t optlen;
1.179 djm 238: int optval, rc, result = -1;
1.141 djm 239:
1.202 djm 240: gettimeofday(&t_start, NULL);
241:
242: if (*timeoutp <= 0) {
243: result = connect(sockfd, serv_addr, addrlen);
244: goto done;
245: }
1.141 djm 246:
1.156 djm 247: set_nonblock(sockfd);
1.141 djm 248: rc = connect(sockfd, serv_addr, addrlen);
1.156 djm 249: if (rc == 0) {
250: unset_nonblock(sockfd);
1.202 djm 251: result = 0;
252: goto done;
253: }
254: if (errno != EINPROGRESS) {
255: result = -1;
256: goto done;
1.156 djm 257: }
1.141 djm 258:
1.179 djm 259: fdset = (fd_set *)xcalloc(howmany(sockfd + 1, NFDBITS),
260: sizeof(fd_mask));
1.141 djm 261: FD_SET(sockfd, fdset);
1.202 djm 262: ms_to_timeval(&tv, *timeoutp);
1.141 djm 263:
1.162 deraadt 264: for (;;) {
1.141 djm 265: rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
266: if (rc != -1 || errno != EINTR)
267: break;
268: }
269:
1.162 deraadt 270: switch (rc) {
1.141 djm 271: case 0:
272: /* Timed out */
273: errno = ETIMEDOUT;
1.142 djm 274: break;
1.141 djm 275: case -1:
276: /* Select error */
1.154 djm 277: debug("select: %s", strerror(errno));
1.142 djm 278: break;
1.141 djm 279: case 1:
280: /* Completed or failed */
281: optval = 0;
282: optlen = sizeof(optval);
1.154 djm 283: if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval,
1.148 markus 284: &optlen) == -1) {
1.154 djm 285: debug("getsockopt: %s", strerror(errno));
1.142 djm 286: break;
1.148 markus 287: }
1.141 djm 288: if (optval != 0) {
289: errno = optval;
1.142 djm 290: break;
1.141 djm 291: }
1.142 djm 292: result = 0;
1.156 djm 293: unset_nonblock(sockfd);
1.141 djm 294: break;
295: default:
296: /* Should not occur */
297: fatal("Bogus return (%d) from select()", rc);
298: }
299:
1.142 djm 300: xfree(fdset);
1.202 djm 301:
302: done:
303: if (result == 0 && *timeoutp > 0) {
304: ms_subtract_diff(&t_start, timeoutp);
305: if (*timeoutp <= 0) {
306: errno = ETIMEDOUT;
307: result = -1;
308: }
309: }
310:
1.142 djm 311: return (result);
1.141 djm 312: }
313:
1.39 deraadt 314: /*
1.49 markus 315: * Opens a TCP/IP connection to the remote server on the given host.
316: * The address of the remote host will be returned in hostaddr.
1.124 markus 317: * If port is 0, the default port will be used. If needpriv is true,
1.39 deraadt 318: * a privileged port will be allocated to make the connection.
1.124 markus 319: * This requires super-user privileges if needpriv is true.
1.39 deraadt 320: * Connection_attempts specifies the maximum number of tries (one per
321: * second). If proxy_command is non-NULL, it specifies the command (with %h
322: * and %p substituted for host and port, respectively) to use to contact
323: * the daemon.
324: */
1.38 markus 325: int
1.49 markus 326: ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
1.202 djm 327: u_short port, int family, int connection_attempts, int *timeout_ms,
328: int want_keepalive, int needpriv, const char *proxy_command)
1.1 deraadt 329: {
1.90 markus 330: int gaierr;
331: int on = 1;
1.49 markus 332: int sock = -1, attempt;
1.90 markus 333: char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1.49 markus 334: struct addrinfo hints, *ai, *aitop;
1.38 markus 335:
1.136 markus 336: debug2("ssh_connect: needpriv %d", needpriv);
1.38 markus 337:
338: /* If a proxy command is given, connect using it. */
339: if (proxy_command != NULL)
1.124 markus 340: return ssh_proxy_connect(host, port, proxy_command);
1.38 markus 341:
342: /* No proxy command. */
343:
1.49 markus 344: memset(&hints, 0, sizeof(hints));
1.115 markus 345: hints.ai_family = family;
1.49 markus 346: hints.ai_socktype = SOCK_STREAM;
1.126 deraadt 347: snprintf(strport, sizeof strport, "%u", port);
1.49 markus 348: if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
1.203 dtucker 349: fatal("%s: Could not resolve hostname %.100s: %s", __progname,
350: host, ssh_gai_strerror(gaierr));
1.38 markus 351:
1.181 markus 352: for (attempt = 0; attempt < connection_attempts; attempt++) {
1.200 markus 353: if (attempt > 0) {
354: /* Sleep a moment before retrying. */
355: sleep(1);
1.38 markus 356: debug("Trying again...");
1.200 markus 357: }
1.181 markus 358: /*
359: * Loop through addresses for this host, and try each one in
360: * sequence until the connection succeeds.
361: */
1.49 markus 362: for (ai = aitop; ai; ai = ai->ai_next) {
363: if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
364: continue;
365: if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
366: ntop, sizeof(ntop), strport, sizeof(strport),
367: NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
368: error("ssh_connect: getnameinfo failed");
369: continue;
370: }
371: debug("Connecting to %.200s [%.100s] port %s.",
372: host, ntop, strport);
373:
374: /* Create a socket for connecting. */
1.139 markus 375: sock = ssh_create_socket(needpriv, ai);
1.49 markus 376: if (sock < 0)
1.110 markus 377: /* Any error is already output */
1.49 markus 378: continue;
379:
1.141 djm 380: if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
1.202 djm 381: timeout_ms) >= 0) {
1.49 markus 382: /* Successful connection. */
1.102 markus 383: memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
1.38 markus 384: break;
1.49 markus 385: } else {
1.131 itojun 386: debug("connect to address %s port %s: %s",
387: ntop, strport, strerror(errno));
1.38 markus 388: close(sock);
1.181 markus 389: sock = -1;
1.38 markus 390: }
391: }
1.181 markus 392: if (sock != -1)
1.49 markus 393: break; /* Successful connection. */
1.38 markus 394: }
1.49 markus 395:
396: freeaddrinfo(aitop);
397:
1.38 markus 398: /* Return failure if we didn't get a successful connection. */
1.181 markus 399: if (sock == -1) {
1.159 markus 400: error("ssh: connect to host %s port %s: %s",
1.130 itojun 401: host, strport, strerror(errno));
1.159 markus 402: return (-1);
1.130 itojun 403: }
1.38 markus 404:
405: debug("Connection established.");
1.90 markus 406:
1.155 markus 407: /* Set SO_KEEPALIVE if requested. */
1.202 djm 408: if (want_keepalive &&
1.90 markus 409: setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
410: sizeof(on)) < 0)
411: error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1.38 markus 412:
413: /* Set the connection. */
414: packet_set_connection(sock, sock);
1.207 dtucker 415: packet_set_timeout(options.server_alive_interval,
416: options.server_alive_count_max);
1.1 deraadt 417:
1.110 markus 418: return 0;
1.59 markus 419: }
420:
1.43 markus 421: /*
1.39 deraadt 422: * Waits for the server identification string, and sends our own
423: * identification string.
424: */
1.213 andreas 425: void
1.202 djm 426: ssh_exchange_identification(int timeout_ms)
1.1 deraadt 427: {
1.38 markus 428: char buf[256], remote_version[256]; /* must be same size! */
1.165 djm 429: int remote_major, remote_minor, mismatch;
1.38 markus 430: int connection_in = packet_get_connection_in();
431: int connection_out = packet_get_connection_out();
1.93 stevesk 432: int minor1 = PROTOCOL_MINOR_1;
1.185 djm 433: u_int i, n;
1.202 djm 434: size_t len;
435: int fdsetsz, remaining, rc;
436: struct timeval t_start, t_remaining;
437: fd_set *fdset;
438:
439: fdsetsz = howmany(connection_in + 1, NFDBITS) * sizeof(fd_mask);
440: fdset = xcalloc(1, fdsetsz);
1.38 markus 441:
1.163 avsm 442: /* Read other side's version identification. */
1.202 djm 443: remaining = timeout_ms;
1.185 djm 444: for (n = 0;;) {
1.75 markus 445: for (i = 0; i < sizeof(buf) - 1; i++) {
1.202 djm 446: if (timeout_ms > 0) {
447: gettimeofday(&t_start, NULL);
448: ms_to_timeval(&t_remaining, remaining);
449: FD_SET(connection_in, fdset);
450: rc = select(connection_in + 1, fdset, NULL,
451: fdset, &t_remaining);
452: ms_subtract_diff(&t_start, &remaining);
453: if (rc == 0 || remaining <= 0)
454: fatal("Connection timed out during "
455: "banner exchange");
456: if (rc == -1) {
457: if (errno == EINTR)
458: continue;
459: fatal("ssh_exchange_identification: "
460: "select: %s", strerror(errno));
461: }
462: }
463:
1.214 andreas 464: len = roaming_atomicio(read, connection_in, &buf[i], 1);
1.163 avsm 465:
1.167 djm 466: if (len != 1 && errno == EPIPE)
1.202 djm 467: fatal("ssh_exchange_identification: "
468: "Connection closed by remote host");
1.163 avsm 469: else if (len != 1)
1.202 djm 470: fatal("ssh_exchange_identification: "
471: "read: %.100s", strerror(errno));
1.75 markus 472: if (buf[i] == '\r') {
473: buf[i] = '\n';
474: buf[i + 1] = 0;
475: continue; /**XXX wait for \n */
476: }
477: if (buf[i] == '\n') {
478: buf[i + 1] = 0;
479: break;
480: }
1.185 djm 481: if (++n > 65536)
1.202 djm 482: fatal("ssh_exchange_identification: "
483: "No banner received");
1.38 markus 484: }
1.75 markus 485: buf[sizeof(buf) - 1] = 0;
1.76 markus 486: if (strncmp(buf, "SSH-", 4) == 0)
1.38 markus 487: break;
1.75 markus 488: debug("ssh_exchange_identification: %s", buf);
1.38 markus 489: }
1.59 markus 490: server_version_string = xstrdup(buf);
1.202 djm 491: xfree(fdset);
1.38 markus 492:
1.40 markus 493: /*
494: * Check that the versions match. In future this might accept
495: * several versions and set appropriate flags to handle them.
496: */
1.59 markus 497: if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
498: &remote_major, &remote_minor, remote_version) != 3)
1.38 markus 499: fatal("Bad remote protocol version identification: '%.100s'", buf);
500: debug("Remote protocol version %d.%d, remote software version %.100s",
1.118 deraadt 501: remote_major, remote_minor, remote_version);
1.38 markus 502:
1.59 markus 503: compat_datafellows(remote_version);
1.64 markus 504: mismatch = 0;
1.59 markus 505:
1.116 deraadt 506: switch (remote_major) {
1.64 markus 507: case 1:
508: if (remote_minor == 99 &&
509: (options.protocol & SSH_PROTO_2) &&
510: !(options.protocol & SSH_PROTO_1_PREFERRED)) {
511: enable_compat20();
512: break;
513: }
514: if (!(options.protocol & SSH_PROTO_1)) {
515: mismatch = 1;
516: break;
517: }
518: if (remote_minor < 3) {
519: fatal("Remote machine has too old SSH software version.");
1.81 markus 520: } else if (remote_minor == 3 || remote_minor == 4) {
1.64 markus 521: /* We speak 1.3, too. */
522: enable_compat13();
1.81 markus 523: minor1 = 3;
1.64 markus 524: if (options.forward_agent) {
1.138 itojun 525: logit("Agent forwarding disabled for protocol 1.3");
1.64 markus 526: options.forward_agent = 0;
527: }
528: }
529: break;
530: case 2:
531: if (options.protocol & SSH_PROTO_2) {
532: enable_compat20();
533: break;
1.38 markus 534: }
1.64 markus 535: /* FALLTHROUGH */
1.68 markus 536: default:
1.64 markus 537: mismatch = 1;
538: break;
1.38 markus 539: }
1.64 markus 540: if (mismatch)
1.38 markus 541: fatal("Protocol major versions differ: %d vs. %d",
1.64 markus 542: (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
543: remote_major);
1.38 markus 544: /* Send our own protocol version identification. */
1.211 dtucker 545: snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s%s",
1.64 markus 546: compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
1.81 markus 547: compat20 ? PROTOCOL_MINOR_2 : minor1,
1.211 dtucker 548: SSH_VERSION, compat20 ? "\r\n" : "\n");
1.214 andreas 549: if (roaming_atomicio(vwrite, connection_out, buf, strlen(buf))
550: != strlen(buf))
1.38 markus 551: fatal("write: %.100s", strerror(errno));
1.59 markus 552: client_version_string = xstrdup(buf);
553: chop(client_version_string);
554: chop(server_version_string);
555: debug("Local version string %.100s", client_version_string);
1.1 deraadt 556: }
557:
1.96 markus 558: /* defaults to 'no' */
1.109 itojun 559: static int
1.112 markus 560: confirm(const char *prompt)
1.1 deraadt 561: {
1.119 markus 562: const char *msg, *again = "Please type 'yes' or 'no': ";
563: char *p;
564: int ret = -1;
1.96 markus 565:
566: if (options.batch_mode)
567: return 0;
1.119 markus 568: for (msg = prompt;;msg = again) {
569: p = read_passphrase(msg, RP_ECHO);
570: if (p == NULL ||
571: (p[0] == '\0') || (p[0] == '\n') ||
572: strncasecmp(p, "no", 2) == 0)
573: ret = 0;
1.127 markus 574: if (p && strncasecmp(p, "yes", 3) == 0)
1.119 markus 575: ret = 1;
576: if (p)
577: xfree(p);
578: if (ret != -1)
579: return ret;
1.1 deraadt 580: }
581: }
582:
1.219 djm 583: static int
584: check_host_cert(const char *host, const Key *host_key)
585: {
586: const char *reason;
587:
588: if (key_cert_check_authority(host_key, 1, 0, host, &reason) != 0) {
589: error("%s", reason);
590: return 0;
591: }
1.223 djm 592: if (buffer_len(&host_key->cert->critical) != 0) {
593: error("Certificate for %s contains unsupported "
594: "critical options(s)", host);
1.219 djm 595: return 0;
596: }
597: return 1;
598: }
599:
1.229 djm 600: static int
601: sockaddr_is_local(struct sockaddr *hostaddr)
602: {
603: switch (hostaddr->sa_family) {
604: case AF_INET:
605: return (ntohl(((struct sockaddr_in *)hostaddr)->
606: sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
607: case AF_INET6:
608: return IN6_IS_ADDR_LOOPBACK(
609: &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
610: default:
611: return 0;
612: }
613: }
614:
615: /*
616: * Prepare the hostname and ip address strings that are used to lookup
617: * host keys in known_hosts files. These may have a port number appended.
618: */
619: void
620: get_hostfile_hostname_ipaddr(char *hostname, struct sockaddr *hostaddr,
621: u_short port, char **hostfile_hostname, char **hostfile_ipaddr)
622: {
623: char ntop[NI_MAXHOST];
624:
625: /*
626: * We don't have the remote ip-address for connections
627: * using a proxy command
628: */
629: if (hostfile_ipaddr != NULL) {
630: if (options.proxy_command == NULL) {
631: if (getnameinfo(hostaddr, hostaddr->sa_len,
632: ntop, sizeof(ntop), NULL, 0, NI_NUMERICHOST) != 0)
633: fatal("check_host_key: getnameinfo failed");
634: *hostfile_ipaddr = put_host_port(ntop, port);
635: } else {
636: *hostfile_ipaddr = xstrdup("<no hostip for proxy "
637: "command>");
638: }
639: }
640:
641: /*
642: * Allow the user to record the key under a different name or
643: * differentiate a non-standard port. This is useful for ssh
644: * tunneling over forwarded connections or if you run multiple
645: * sshd's on different ports on the same machine.
646: */
647: if (hostfile_hostname != NULL) {
648: if (options.host_key_alias != NULL) {
649: *hostfile_hostname = xstrdup(options.host_key_alias);
650: debug("using hostkeyalias: %s", *hostfile_hostname);
651: } else {
652: *hostfile_hostname = put_host_port(hostname, port);
653: }
654: }
655: }
656:
1.39 deraadt 657: /*
1.108 markus 658: * check whether the supplied host key is valid, return -1 if the key
659: * is not valid. the user_hostfile will not be updated if 'readonly' is true.
1.39 deraadt 660: */
1.197 dtucker 661: #define RDRW 0
662: #define RDONLY 1
663: #define ROQUIET 2
1.109 itojun 664: static int
1.197 dtucker 665: check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port,
1.229 djm 666: Key *host_key, int readonly, char *user_hostfile,
667: char *system_hostfile)
1.1 deraadt 668: {
1.229 djm 669: Key *raw_key = NULL;
1.219 djm 670: const char *type;
1.189 dtucker 671: char *ip = NULL, *host = NULL;
1.204 grunk 672: char hostline[1000], *hostp, *fp, *ra;
1.38 markus 673: HostStatus host_status;
674: HostStatus ip_status;
1.229 djm 675: int r, want_cert = key_is_cert(host_key), host_ip_differ = 0;
676: int local = sockaddr_is_local(hostaddr);
1.119 markus 677: char msg[1024];
1.229 djm 678: int len, cancelled_forwarding = 0;
679: struct hostkeys *host_hostkeys, *ip_hostkeys;
680: const struct hostkey_entry *host_found, *ip_found;
1.49 markus 681:
682: /*
683: * Force accepting of the host key for loopback/localhost. The
684: * problem is that if the home directory is NFS-mounted to multiple
685: * machines, localhost will refer to a different machine in each of
686: * them, and the user will get bogus HOST_CHANGED warnings. This
687: * essentially disables host authentication for localhost; however,
688: * this is probably not a real problem.
689: */
1.111 markus 690: if (options.no_host_authentication_for_localhost == 1 && local &&
691: options.host_key_alias == NULL) {
1.88 markus 692: debug("Forcing accepting of host key for "
693: "loopback/localhost.");
1.108 markus 694: return 0;
1.49 markus 695: }
1.42 markus 696:
697: /*
1.229 djm 698: * Prepare the hostname and address strings used for hostkey lookup.
699: * In some cases, these will have a port number appended.
1.42 markus 700: */
1.229 djm 701: get_hostfile_hostname_ipaddr(hostname, hostaddr, port, &host, &ip);
1.206 grunk 702:
703: /*
1.88 markus 704: * Turn off check_host_ip if the connection is to localhost, via proxy
705: * command or if we don't have a hostname to compare with
706: */
1.189 dtucker 707: if (options.check_host_ip && (local ||
708: strcmp(hostname, ip) == 0 || options.proxy_command != NULL))
1.88 markus 709: options.check_host_ip = 0;
1.86 markus 710:
1.229 djm 711: host_hostkeys = init_hostkeys();
712: load_hostkeys(host_hostkeys, host, user_hostfile);
713: load_hostkeys(host_hostkeys, host, system_hostfile);
714:
715: ip_hostkeys = NULL;
716: if (!want_cert && options.check_host_ip) {
717: ip_hostkeys = init_hostkeys();
718: load_hostkeys(ip_hostkeys, ip, user_hostfile);
719: load_hostkeys(ip_hostkeys, ip, system_hostfile);
1.84 markus 720: }
1.38 markus 721:
1.219 djm 722: retry:
1.229 djm 723: /* Reload these as they may have changed on cert->key downgrade */
1.219 djm 724: want_cert = key_is_cert(host_key);
725: type = key_type(host_key);
726:
1.46 markus 727: /*
1.170 djm 728: * Check if the host key is present in the user's list of known
1.40 markus 729: * hosts or in the systemwide list.
730: */
1.229 djm 731: host_status = check_key_in_hostkeys(host_hostkeys, host_key,
732: &host_found);
733:
1.40 markus 734: /*
735: * Also perform check for the ip address, skip the check if we are
1.219 djm 736: * localhost, looking for a certificate, or the hostname was an ip
737: * address to begin with.
1.40 markus 738: */
1.229 djm 739: if (!want_cert && ip_hostkeys != NULL) {
740: ip_status = check_key_in_hostkeys(ip_hostkeys, host_key,
741: &ip_found);
1.38 markus 742: if (host_status == HOST_CHANGED &&
1.229 djm 743: (ip_status != HOST_CHANGED ||
744: (ip_found != NULL &&
745: !key_equal(ip_found->key, host_found->key))))
1.38 markus 746: host_ip_differ = 1;
747: } else
748: ip_status = host_status;
749:
750: switch (host_status) {
751: case HOST_OK:
752: /* The host is known and the key matches. */
1.219 djm 753: debug("Host '%.200s' is known and matches the %s host %s.",
754: host, type, want_cert ? "certificate" : "key");
1.229 djm 755: debug("Found %s in %s:%lu", want_cert ? "CA key" : "key",
756: host_found->file, host_found->line);
1.219 djm 757: if (want_cert && !check_host_cert(hostname, host_key))
758: goto fail;
1.88 markus 759: if (options.check_host_ip && ip_status == HOST_NEW) {
1.219 djm 760: if (readonly || want_cert)
1.138 itojun 761: logit("%s host key for IP address "
1.108 markus 762: "'%.128s' not in list of known hosts.",
763: type, ip);
764: else if (!add_host_to_hostfile(user_hostfile, ip,
1.160 djm 765: host_key, options.hash_known_hosts))
1.138 itojun 766: logit("Failed to add the %s host key for IP "
1.108 markus 767: "address '%.128s' to the list of known "
768: "hosts (%.30s).", type, ip, user_hostfile);
1.88 markus 769: else
1.138 itojun 770: logit("Warning: Permanently added the %s host "
1.108 markus 771: "key for IP address '%.128s' to the list "
772: "of known hosts.", type, ip);
1.209 grunk 773: } else if (options.visual_host_key) {
1.204 grunk 774: fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
775: ra = key_fingerprint(host_key, SSH_FP_MD5,
776: SSH_FP_RANDOMART);
777: logit("Host key fingerprint is %s\n%s\n", fp, ra);
778: xfree(ra);
779: xfree(fp);
1.38 markus 780: }
781: break;
782: case HOST_NEW:
1.197 dtucker 783: if (options.host_key_alias == NULL && port != 0 &&
784: port != SSH_DEFAULT_PORT) {
785: debug("checking without port identifier");
1.212 stevesk 786: if (check_host_key(hostname, hostaddr, 0, host_key,
787: ROQUIET, user_hostfile, system_hostfile) == 0) {
1.197 dtucker 788: debug("found matching key w/out port");
789: break;
790: }
791: }
1.219 djm 792: if (readonly || want_cert)
1.108 markus 793: goto fail;
1.38 markus 794: /* The host is new. */
795: if (options.strict_host_key_checking == 1) {
1.108 markus 796: /*
797: * User has requested strict host key checking. We
798: * will not add the host key automatically. The only
799: * alternative left is to abort.
800: */
801: error("No %s host key is known for %.200s and you "
802: "have requested strict checking.", type, host);
803: goto fail;
1.38 markus 804: } else if (options.strict_host_key_checking == 2) {
1.145 jakob 805: char msg1[1024], msg2[1024];
806:
1.229 djm 807: if (show_other_keys(host_hostkeys, host_key))
1.145 jakob 808: snprintf(msg1, sizeof(msg1),
1.168 djm 809: "\nbut keys of different type are already"
810: " known for this host.");
1.145 jakob 811: else
812: snprintf(msg1, sizeof(msg1), ".");
1.38 markus 813: /* The default */
1.100 markus 814: fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1.204 grunk 815: ra = key_fingerprint(host_key, SSH_FP_MD5,
816: SSH_FP_RANDOMART);
1.145 jakob 817: msg2[0] = '\0';
818: if (options.verify_host_key_dns) {
1.153 jakob 819: if (matching_host_key_dns)
1.145 jakob 820: snprintf(msg2, sizeof(msg2),
821: "Matching host key fingerprint"
822: " found in DNS.\n");
823: else
824: snprintf(msg2, sizeof(msg2),
825: "No matching host key fingerprint"
826: " found in DNS.\n");
827: }
1.119 markus 828: snprintf(msg, sizeof(msg),
1.108 markus 829: "The authenticity of host '%.200s (%s)' can't be "
1.132 markus 830: "established%s\n"
1.209 grunk 831: "%s key fingerprint is %s.%s%s\n%s"
1.108 markus 832: "Are you sure you want to continue connecting "
1.132 markus 833: "(yes/no)? ",
1.209 grunk 834: host, ip, msg1, type, fp,
835: options.visual_host_key ? "\n" : "",
836: options.visual_host_key ? ra : "",
837: msg2);
1.204 grunk 838: xfree(ra);
1.100 markus 839: xfree(fp);
1.119 markus 840: if (!confirm(msg))
1.108 markus 841: goto fail;
1.38 markus 842: }
1.161 djm 843: /*
844: * If not in strict mode, add the key automatically to the
845: * local known_hosts file.
846: */
1.88 markus 847: if (options.check_host_ip && ip_status == HOST_NEW) {
1.229 djm 848: snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
1.38 markus 849: hostp = hostline;
1.161 djm 850: if (options.hash_known_hosts) {
851: /* Add hash of host and IP separately */
852: r = add_host_to_hostfile(user_hostfile, host,
853: host_key, options.hash_known_hosts) &&
854: add_host_to_hostfile(user_hostfile, ip,
855: host_key, options.hash_known_hosts);
856: } else {
857: /* Add unhashed "host,ip" */
858: r = add_host_to_hostfile(user_hostfile,
859: hostline, host_key,
860: options.hash_known_hosts);
861: }
862: } else {
863: r = add_host_to_hostfile(user_hostfile, host, host_key,
864: options.hash_known_hosts);
1.38 markus 865: hostp = host;
1.161 djm 866: }
1.38 markus 867:
1.161 djm 868: if (!r)
1.138 itojun 869: logit("Failed to add the host to the list of known "
1.108 markus 870: "hosts (%.500s).", user_hostfile);
1.38 markus 871: else
1.138 itojun 872: logit("Warning: Permanently added '%.200s' (%s) to the "
1.108 markus 873: "list of known hosts.", hostp, type);
1.38 markus 874: break;
1.220 djm 875: case HOST_REVOKED:
876: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
877: error("@ WARNING: REVOKED HOST KEY DETECTED! @");
878: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
879: error("The %s host key for %s is marked as revoked.", type, host);
880: error("This could mean that a stolen key is being used to");
881: error("impersonate this host.");
882:
883: /*
884: * If strict host key checking is in use, the user will have
885: * to edit the key manually and we can only abort.
886: */
887: if (options.strict_host_key_checking) {
888: error("%s host key for %.200s was revoked and you have "
889: "requested strict checking.", type, host);
890: goto fail;
891: }
892: goto continue_unsafe;
893:
1.38 markus 894: case HOST_CHANGED:
1.219 djm 895: if (want_cert) {
896: /*
897: * This is only a debug() since it is valid to have
898: * CAs with wildcard DNS matches that don't match
899: * all hosts that one might visit.
900: */
901: debug("Host certificate authority does not "
1.229 djm 902: "match %s in %s:%lu", CA_MARKER,
903: host_found->file, host_found->line);
1.219 djm 904: goto fail;
905: }
1.197 dtucker 906: if (readonly == ROQUIET)
907: goto fail;
1.38 markus 908: if (options.check_host_ip && host_ip_differ) {
1.158 avsm 909: char *key_msg;
1.38 markus 910: if (ip_status == HOST_NEW)
1.158 avsm 911: key_msg = "is unknown";
1.38 markus 912: else if (ip_status == HOST_OK)
1.158 avsm 913: key_msg = "is unchanged";
1.38 markus 914: else
1.158 avsm 915: key_msg = "has a different value";
1.38 markus 916: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
917: error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
918: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1.72 markus 919: error("The %s host key for %s has changed,", type, host);
1.208 ian 920: error("and the key for the corresponding IP address %s", ip);
1.158 avsm 921: error("%s. This could either mean that", key_msg);
1.38 markus 922: error("DNS SPOOFING is happening or the IP address for the host");
1.85 markus 923: error("and its host key have changed at the same time.");
1.88 markus 924: if (ip_status != HOST_NEW)
1.229 djm 925: error("Offending key for IP in %s:%lu",
926: ip_found->file, ip_found->line);
1.38 markus 927: }
928: /* The host key has changed. */
1.150 jakob 929: warn_changed_key(host_key);
1.38 markus 930: error("Add correct host key in %.100s to get rid of this message.",
1.87 markus 931: user_hostfile);
1.229 djm 932: error("Offending %s key in %s:%lu", key_type(host_found->key),
933: host_found->file, host_found->line);
1.38 markus 934:
1.40 markus 935: /*
936: * If strict host key checking is in use, the user will have
937: * to edit the key manually and we can only abort.
938: */
1.108 markus 939: if (options.strict_host_key_checking) {
940: error("%s host key for %.200s has changed and you have "
941: "requested strict checking.", type, host);
942: goto fail;
943: }
1.38 markus 944:
1.220 djm 945: continue_unsafe:
1.40 markus 946: /*
947: * If strict host key checking has not been requested, allow
1.144 djm 948: * the connection but without MITM-able authentication or
1.194 stevesk 949: * forwarding.
1.40 markus 950: */
1.38 markus 951: if (options.password_authentication) {
1.108 markus 952: error("Password authentication is disabled to avoid "
953: "man-in-the-middle attacks.");
1.38 markus 954: options.password_authentication = 0;
1.210 dtucker 955: cancelled_forwarding = 1;
1.144 djm 956: }
957: if (options.kbd_interactive_authentication) {
958: error("Keyboard-interactive authentication is disabled"
959: " to avoid man-in-the-middle attacks.");
960: options.kbd_interactive_authentication = 0;
961: options.challenge_response_authentication = 0;
1.210 dtucker 962: cancelled_forwarding = 1;
1.144 djm 963: }
964: if (options.challenge_response_authentication) {
965: error("Challenge/response authentication is disabled"
966: " to avoid man-in-the-middle attacks.");
967: options.challenge_response_authentication = 0;
1.210 dtucker 968: cancelled_forwarding = 1;
1.38 markus 969: }
970: if (options.forward_agent) {
1.108 markus 971: error("Agent forwarding is disabled to avoid "
972: "man-in-the-middle attacks.");
1.38 markus 973: options.forward_agent = 0;
1.210 dtucker 974: cancelled_forwarding = 1;
1.83 markus 975: }
976: if (options.forward_x11) {
1.108 markus 977: error("X11 forwarding is disabled to avoid "
978: "man-in-the-middle attacks.");
1.83 markus 979: options.forward_x11 = 0;
1.210 dtucker 980: cancelled_forwarding = 1;
1.83 markus 981: }
1.108 markus 982: if (options.num_local_forwards > 0 ||
983: options.num_remote_forwards > 0) {
984: error("Port forwarding is disabled to avoid "
985: "man-in-the-middle attacks.");
986: options.num_local_forwards =
1.118 deraadt 987: options.num_remote_forwards = 0;
1.210 dtucker 988: cancelled_forwarding = 1;
1.194 stevesk 989: }
990: if (options.tun_open != SSH_TUNMODE_NO) {
991: error("Tunnel forwarding is disabled to avoid "
992: "man-in-the-middle attacks.");
993: options.tun_open = SSH_TUNMODE_NO;
1.210 dtucker 994: cancelled_forwarding = 1;
1.38 markus 995: }
1.210 dtucker 996: if (options.exit_on_forward_failure && cancelled_forwarding)
997: fatal("Error: forwarding disabled due to host key "
998: "check failure");
999:
1.40 markus 1000: /*
1001: * XXX Should permit the user to change to use the new id.
1002: * This could be done by converting the host key to an
1003: * identifying sentence, tell that the host identifies itself
1.218 dtucker 1004: * by that sentence, and ask the user if he/she wishes to
1.40 markus 1005: * accept the authentication.
1006: */
1.38 markus 1007: break;
1.132 markus 1008: case HOST_FOUND:
1009: fatal("internal error");
1010: break;
1.88 markus 1011: }
1012:
1013: if (options.check_host_ip && host_status != HOST_CHANGED &&
1014: ip_status == HOST_CHANGED) {
1.119 markus 1015: snprintf(msg, sizeof(msg),
1016: "Warning: the %s host key for '%.200s' "
1017: "differs from the key for the IP address '%.128s'"
1.229 djm 1018: "\nOffending key for IP in %s:%lu",
1019: type, host, ip, ip_found->file, ip_found->line);
1.119 markus 1020: if (host_status == HOST_OK) {
1021: len = strlen(msg);
1022: snprintf(msg + len, sizeof(msg) - len,
1.229 djm 1023: "\nMatching host key in %s:%lu",
1024: host_found->file, host_found->line);
1.119 markus 1025: }
1.88 markus 1026: if (options.strict_host_key_checking == 1) {
1.143 djm 1027: logit("%s", msg);
1.108 markus 1028: error("Exiting, you have requested strict checking.");
1029: goto fail;
1.88 markus 1030: } else if (options.strict_host_key_checking == 2) {
1.119 markus 1031: strlcat(msg, "\nAre you sure you want "
1032: "to continue connecting (yes/no)? ", sizeof(msg));
1033: if (!confirm(msg))
1.108 markus 1034: goto fail;
1.119 markus 1035: } else {
1.143 djm 1036: logit("%s", msg);
1.88 markus 1037: }
1.38 markus 1038: }
1.82 provos 1039:
1040: xfree(ip);
1.189 dtucker 1041: xfree(host);
1.229 djm 1042: if (host_hostkeys != NULL)
1043: free_hostkeys(host_hostkeys);
1044: if (ip_hostkeys != NULL)
1045: free_hostkeys(ip_hostkeys);
1.108 markus 1046: return 0;
1047:
1048: fail:
1.220 djm 1049: if (want_cert && host_status != HOST_REVOKED) {
1.219 djm 1050: /*
1051: * No matching certificate. Downgrade cert to raw key and
1052: * search normally.
1053: */
1054: debug("No matching CA found. Retry with plain key");
1055: raw_key = key_from_private(host_key);
1056: if (key_drop_cert(raw_key) != 0)
1057: fatal("Couldn't drop certificate");
1058: host_key = raw_key;
1059: goto retry;
1060: }
1061: if (raw_key != NULL)
1062: key_free(raw_key);
1.108 markus 1063: xfree(ip);
1.189 dtucker 1064: xfree(host);
1.229 djm 1065: if (host_hostkeys != NULL)
1066: free_hostkeys(host_hostkeys);
1067: if (ip_hostkeys != NULL)
1068: free_hostkeys(ip_hostkeys);
1.108 markus 1069: return -1;
1070: }
1071:
1.140 jakob 1072: /* returns 0 if key verifies or -1 if key does NOT verify */
1.108 markus 1073: int
1074: verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
1075: {
1076: struct stat st;
1.153 jakob 1077: int flags = 0;
1.229 djm 1078: char *fp;
1079:
1080: fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1081: debug("Server host key: %s %s", key_type(host_key), fp);
1082: xfree(fp);
1.140 jakob 1083:
1.219 djm 1084: /* XXX certs are not yet supported for DNS */
1085: if (!key_is_cert(host_key) && options.verify_host_key_dns &&
1.153 jakob 1086: verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
1087:
1088: if (flags & DNS_VERIFY_FOUND) {
1089:
1090: if (options.verify_host_key_dns == 1 &&
1091: flags & DNS_VERIFY_MATCH &&
1092: flags & DNS_VERIFY_SECURE)
1093: return 0;
1094:
1095: if (flags & DNS_VERIFY_MATCH) {
1096: matching_host_key_dns = 1;
1097: } else {
1098: warn_changed_key(host_key);
1099: error("Update the SSHFP RR in DNS with the new "
1100: "host key to get rid of this message.");
1101: }
1.140 jakob 1102: }
1103: }
1.108 markus 1104:
1105: /* return ok if the key can be found in an old keyfile */
1106: if (stat(options.system_hostfile2, &st) == 0 ||
1107: stat(options.user_hostfile2, &st) == 0) {
1.197 dtucker 1108: if (check_host_key(host, hostaddr, options.port, host_key,
1109: RDONLY, options.user_hostfile2,
1110: options.system_hostfile2) == 0)
1.108 markus 1111: return 0;
1112: }
1.197 dtucker 1113: return check_host_key(host, hostaddr, options.port, host_key,
1114: RDRW, options.user_hostfile, options.system_hostfile);
1.51 markus 1115: }
1.70 markus 1116:
1.51 markus 1117: /*
1118: * Starts a dialog with the server, and authenticates the current user on the
1119: * server. This does not need any extra privileges. The basic connection
1120: * to the server must already have been established before this is called.
1121: * If login fails, this function prints an error and never returns.
1122: * This function does not require super-user privileges.
1123: */
1124: void
1.120 markus 1125: ssh_login(Sensitive *sensitive, const char *orighost,
1.229 djm 1126: struct sockaddr *hostaddr, u_short port, struct passwd *pw, int timeout_ms)
1.51 markus 1127: {
1128: char *host, *cp;
1.70 markus 1129: char *server_user, *local_user;
1130:
1131: local_user = xstrdup(pw->pw_name);
1132: server_user = options.user ? options.user : local_user;
1.51 markus 1133:
1134: /* Convert the user-supplied hostname into all lowercase. */
1135: host = xstrdup(orighost);
1136: for (cp = host; *cp; cp++)
1137: if (isupper(*cp))
1.178 deraadt 1138: *cp = (char)tolower(*cp);
1.51 markus 1139:
1140: /* Exchange protocol version identification strings with the server. */
1.202 djm 1141: ssh_exchange_identification(timeout_ms);
1.51 markus 1142:
1143: /* Put the connection into non-blocking mode. */
1144: packet_set_nonblocking();
1145:
1146: /* key exchange */
1147: /* authenticate user */
1.59 markus 1148: if (compat20) {
1.229 djm 1149: ssh_kex2(host, hostaddr, port);
1.120 markus 1150: ssh_userauth2(local_user, server_user, host, sensitive);
1.59 markus 1151: } else {
1152: ssh_kex(host, hostaddr);
1.120 markus 1153: ssh_userauth1(local_user, server_user, host, sensitive);
1.59 markus 1154: }
1.182 markus 1155: xfree(local_user);
1.97 markus 1156: }
1157:
1158: void
1159: ssh_put_password(char *password)
1160: {
1161: int size;
1162: char *padded;
1163:
1.99 deraadt 1164: if (datafellows & SSH_BUG_PASSWORDPAD) {
1.107 markus 1165: packet_put_cstring(password);
1.99 deraadt 1166: return;
1167: }
1.97 markus 1168: size = roundup(strlen(password) + 1, 32);
1.179 djm 1169: padded = xcalloc(1, size);
1.97 markus 1170: strlcpy(padded, password, size);
1171: packet_put_string(padded, size);
1172: memset(padded, 0, size);
1173: xfree(padded);
1.132 markus 1174: }
1175:
1176: /* print all known host keys for a given host, but skip keys of given type */
1177: static int
1.229 djm 1178: show_other_keys(struct hostkeys *hostkeys, Key *key)
1.132 markus 1179: {
1.225 djm 1180: int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, KEY_ECDSA, -1};
1.229 djm 1181: int i, ret = 0;
1182: char *fp, *ra;
1183: const struct hostkey_entry *found;
1.132 markus 1184:
1185: for (i = 0; type[i] != -1; i++) {
1186: if (type[i] == key->type)
1187: continue;
1.229 djm 1188: if (!lookup_key_in_hostkeys_by_type(hostkeys, type[i], &found))
1.132 markus 1189: continue;
1.229 djm 1190: fp = key_fingerprint(found->key, SSH_FP_MD5, SSH_FP_HEX);
1191: ra = key_fingerprint(found->key, SSH_FP_MD5, SSH_FP_RANDOMART);
1192: logit("WARNING: %s key found for host %s\n"
1193: "in %s:%lu\n"
1194: "%s key fingerprint %s.",
1195: key_type(found->key),
1196: found->host, found->file, found->line,
1197: key_type(found->key), fp);
1198: if (options.visual_host_key)
1199: logit("%s", ra);
1200: xfree(ra);
1201: xfree(fp);
1202: ret = 1;
1.132 markus 1203: }
1.229 djm 1204: return ret;
1.150 jakob 1205: }
1206:
1207: static void
1208: warn_changed_key(Key *host_key)
1209: {
1210: char *fp;
1211:
1212: fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1213:
1214: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1215: error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
1216: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1217: error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
1218: error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
1.230 ! markus 1219: error("It is also possible that a host key has just been changed.");
1.150 jakob 1220: error("The fingerprint for the %s key sent by the remote host is\n%s.",
1.230 ! markus 1221: key_type(host_key), fp);
1.150 jakob 1222: error("Please contact your system administrator.");
1223:
1224: xfree(fp);
1.171 reyk 1225: }
1226:
1227: /*
1228: * Execute a local command
1229: */
1230: int
1231: ssh_local_cmd(const char *args)
1232: {
1233: char *shell;
1234: pid_t pid;
1235: int status;
1236:
1237: if (!options.permit_local_command ||
1238: args == NULL || !*args)
1239: return (1);
1240:
1.226 djm 1241: if ((shell = getenv("SHELL")) == NULL || *shell == '\0')
1.171 reyk 1242: shell = _PATH_BSHELL;
1243:
1244: pid = fork();
1245: if (pid == 0) {
1246: debug3("Executing %s -c \"%s\"", shell, args);
1247: execl(shell, shell, "-c", args, (char *)NULL);
1248: error("Couldn't execute %s -c \"%s\": %s",
1249: shell, args, strerror(errno));
1250: _exit(1);
1251: } else if (pid == -1)
1252: fatal("fork failed: %.100s", strerror(errno));
1253: while (waitpid(pid, &status, 0) == -1)
1254: if (errno != EINTR)
1255: fatal("Couldn't wait for child: %s", strerror(errno));
1256:
1257: if (!WIFEXITED(status))
1258: return (1);
1259:
1260: return (WEXITSTATUS(status));
1.1 deraadt 1261: }