Annotation of src/usr.bin/ssh/sshconnect.c, Revision 1.233
1.233 ! djm 1: /* $OpenBSD: sshconnect.c,v 1.232 2011/01/16 11:50:36 djm Exp $ */
1.1 deraadt 2: /*
1.39 deraadt 3: * Author: Tatu Ylonen <ylo@cs.hut.fi>
4: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5: * All rights reserved
6: * Code to connect to a remote host, and to perform the client side of the
7: * login (authentication) dialog.
1.78 deraadt 8: *
9: * As far as I am concerned, the code I have written for this software
10: * can be used freely for any purpose. Any derived versions of this
11: * software must be clearly marked as such, and if the derived work is
12: * incompatible with the protocol description in the RFC file, it must be
13: * called by a name other than "ssh" or "Secure Shell".
1.39 deraadt 14: */
1.1 deraadt 15:
1.174 stevesk 16: #include <sys/types.h>
17: #include <sys/wait.h>
1.175 stevesk 18: #include <sys/stat.h>
1.187 stevesk 19: #include <sys/socket.h>
1.195 stevesk 20: #include <sys/time.h>
1.187 stevesk 21:
22: #include <netinet/in.h>
1.172 stevesk 23:
1.176 stevesk 24: #include <ctype.h>
1.190 stevesk 25: #include <errno.h>
1.216 dtucker 26: #include <fcntl.h>
1.191 stevesk 27: #include <netdb.h>
1.172 stevesk 28: #include <paths.h>
1.199 deraadt 29: #include <signal.h>
1.188 stevesk 30: #include <pwd.h>
1.198 stevesk 31: #include <stdio.h>
1.196 stevesk 32: #include <stdlib.h>
1.193 stevesk 33: #include <string.h>
1.192 stevesk 34: #include <unistd.h>
1.71 markus 35:
1.199 deraadt 36: #include "xmalloc.h"
1.91 markus 37: #include "ssh.h"
1.1 deraadt 38: #include "rsa.h"
1.59 markus 39: #include "buffer.h"
1.1 deraadt 40: #include "packet.h"
41: #include "uidswap.h"
1.21 markus 42: #include "compat.h"
1.58 markus 43: #include "key.h"
1.71 markus 44: #include "sshconnect.h"
1.58 markus 45: #include "hostfile.h"
1.91 markus 46: #include "log.h"
47: #include "readconf.h"
48: #include "atomicio.h"
49: #include "misc.h"
1.140 jakob 50: #include "dns.h"
1.214 andreas 51: #include "roaming.h"
1.219 djm 52: #include "ssh2.h"
1.186 stevesk 53: #include "version.h"
1.140 jakob 54:
1.70 markus 55: char *client_version_string = NULL;
56: char *server_version_string = NULL;
1.59 markus 57:
1.169 stevesk 58: static int matching_host_key_dns = 0;
1.145 jakob 59:
1.227 djm 60: static pid_t proxy_command_pid = 0;
61:
1.124 markus 62: /* import */
1.43 markus 63: extern Options options;
1.50 markus 64: extern char *__progname;
1.124 markus 65: extern uid_t original_real_uid;
66: extern uid_t original_effective_uid;
1.91 markus 67:
1.229 djm 68: static int show_other_keys(struct hostkeys *, Key *);
1.150 jakob 69: static void warn_changed_key(Key *);
1.132 markus 70:
1.39 deraadt 71: /*
72: * Connect to the given ssh server using a proxy command.
73: */
1.109 itojun 74: static int
1.124 markus 75: ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
1.1 deraadt 76: {
1.164 djm 77: char *command_string, *tmp;
1.38 markus 78: int pin[2], pout[2];
1.69 deraadt 79: pid_t pid;
1.201 djm 80: char *shell, strport[NI_MAXSERV];
81:
1.226 djm 82: if ((shell = getenv("SHELL")) == NULL || *shell == '\0')
1.201 djm 83: shell = _PATH_BSHELL;
1.38 markus 84:
85: /* Convert the port number into a string. */
1.49 markus 86: snprintf(strport, sizeof strport, "%hu", port);
1.38 markus 87:
1.135 djm 88: /*
89: * Build the final command string in the buffer by making the
90: * appropriate substitutions to the given proxy command.
91: *
1.154 djm 92: * Use "exec" to avoid "sh -c" processes on some platforms
1.135 djm 93: * (e.g. Solaris)
94: */
1.179 djm 95: xasprintf(&tmp, "exec %s", proxy_command);
1.222 djm 96: command_string = percent_expand(tmp, "h", host, "p", strport,
1.224 djm 97: "r", options.user, (char *)NULL);
1.164 djm 98: xfree(tmp);
1.38 markus 99:
100: /* Create pipes for communicating with the proxy. */
101: if (pipe(pin) < 0 || pipe(pout) < 0)
102: fatal("Could not create pipes to communicate with the proxy: %.100s",
1.118 deraadt 103: strerror(errno));
1.38 markus 104:
105: debug("Executing proxy command: %.500s", command_string);
106:
107: /* Fork and execute the proxy command. */
108: if ((pid = fork()) == 0) {
109: char *argv[10];
110:
111: /* Child. Permanently give up superuser privileges. */
1.184 markus 112: permanently_drop_suid(original_real_uid);
1.38 markus 113:
114: /* Redirect stdin and stdout. */
115: close(pin[1]);
116: if (pin[0] != 0) {
117: if (dup2(pin[0], 0) < 0)
118: perror("dup2 stdin");
119: close(pin[0]);
120: }
121: close(pout[0]);
122: if (dup2(pout[1], 1) < 0)
123: perror("dup2 stdout");
124: /* Cannot be 1 because pin allocated two descriptors. */
125: close(pout[1]);
126:
127: /* Stderr is left as it is so that error messages get
128: printed on the user's terminal. */
1.201 djm 129: argv[0] = shell;
1.38 markus 130: argv[1] = "-c";
131: argv[2] = command_string;
132: argv[3] = NULL;
133:
134: /* Execute the proxy command. Note that we gave up any
135: extra privileges above. */
1.232 djm 136: signal(SIGPIPE, SIG_DFL);
1.89 markus 137: execv(argv[0], argv);
138: perror(argv[0]);
1.38 markus 139: exit(1);
140: }
141: /* Parent. */
142: if (pid < 0)
143: fatal("fork failed: %.100s", strerror(errno));
1.135 djm 144: else
145: proxy_command_pid = pid; /* save pid to clean up later */
1.38 markus 146:
147: /* Close child side of the descriptors. */
148: close(pin[0]);
149: close(pout[1]);
150:
151: /* Free the command name. */
1.164 djm 152: xfree(command_string);
1.38 markus 153:
154: /* Set the connection file descriptors. */
155: packet_set_connection(pout[0], pin[1]);
1.207 dtucker 156: packet_set_timeout(options.server_alive_interval,
157: options.server_alive_count_max);
1.1 deraadt 158:
1.110 markus 159: /* Indicate OK return */
160: return 0;
1.227 djm 161: }
162:
163: void
164: ssh_kill_proxy_command(void)
165: {
166: /*
167: * Send SIGHUP to proxy command if used. We don't wait() in
168: * case it hangs and instead rely on init to reap the child
169: */
170: if (proxy_command_pid > 1)
1.228 djm 171: kill(proxy_command_pid, SIGHUP);
1.1 deraadt 172: }
173:
1.39 deraadt 174: /*
175: * Creates a (possibly privileged) socket for use as the ssh connection.
176: */
1.109 itojun 177: static int
1.139 markus 178: ssh_create_socket(int privileged, struct addrinfo *ai)
1.1 deraadt 179: {
1.105 markus 180: int sock, gaierr;
181: struct addrinfo hints, *res;
1.1 deraadt 182:
1.40 markus 183: /*
184: * If we are running as root and want to connect to a privileged
185: * port, bind our own socket to a privileged port.
186: */
1.38 markus 187: if (privileged) {
188: int p = IPPORT_RESERVED - 1;
1.124 markus 189: PRIV_START;
1.139 markus 190: sock = rresvport_af(&p, ai->ai_family);
1.124 markus 191: PRIV_END;
1.38 markus 192: if (sock < 0)
1.139 markus 193: error("rresvport: af=%d %.100s", ai->ai_family,
194: strerror(errno));
1.55 markus 195: else
196: debug("Allocated local port %d.", p);
1.105 markus 197: return sock;
198: }
1.217 dtucker 199: sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
1.216 dtucker 200: if (sock < 0) {
1.105 markus 201: error("socket: %.100s", strerror(errno));
1.216 dtucker 202: return -1;
203: }
204: fcntl(sock, F_SETFD, FD_CLOEXEC);
1.105 markus 205:
206: /* Bind the socket to an alternative local IP address */
207: if (options.bind_address == NULL)
208: return sock;
209:
210: memset(&hints, 0, sizeof(hints));
1.139 markus 211: hints.ai_family = ai->ai_family;
212: hints.ai_socktype = ai->ai_socktype;
213: hints.ai_protocol = ai->ai_protocol;
1.105 markus 214: hints.ai_flags = AI_PASSIVE;
1.205 dtucker 215: gaierr = getaddrinfo(options.bind_address, NULL, &hints, &res);
1.105 markus 216: if (gaierr) {
217: error("getaddrinfo: %s: %s", options.bind_address,
1.203 dtucker 218: ssh_gai_strerror(gaierr));
1.105 markus 219: close(sock);
220: return -1;
221: }
222: if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
223: error("bind: %s: %s", options.bind_address, strerror(errno));
224: close(sock);
225: freeaddrinfo(res);
226: return -1;
1.38 markus 227: }
1.105 markus 228: freeaddrinfo(res);
1.38 markus 229: return sock;
1.1 deraadt 230: }
231:
1.141 djm 232: static int
233: timeout_connect(int sockfd, const struct sockaddr *serv_addr,
1.202 djm 234: socklen_t addrlen, int *timeoutp)
1.141 djm 235: {
236: fd_set *fdset;
1.202 djm 237: struct timeval tv, t_start;
1.141 djm 238: socklen_t optlen;
1.179 djm 239: int optval, rc, result = -1;
1.141 djm 240:
1.202 djm 241: gettimeofday(&t_start, NULL);
242:
243: if (*timeoutp <= 0) {
244: result = connect(sockfd, serv_addr, addrlen);
245: goto done;
246: }
1.141 djm 247:
1.156 djm 248: set_nonblock(sockfd);
1.141 djm 249: rc = connect(sockfd, serv_addr, addrlen);
1.156 djm 250: if (rc == 0) {
251: unset_nonblock(sockfd);
1.202 djm 252: result = 0;
253: goto done;
254: }
255: if (errno != EINPROGRESS) {
256: result = -1;
257: goto done;
1.156 djm 258: }
1.141 djm 259:
1.179 djm 260: fdset = (fd_set *)xcalloc(howmany(sockfd + 1, NFDBITS),
261: sizeof(fd_mask));
1.141 djm 262: FD_SET(sockfd, fdset);
1.202 djm 263: ms_to_timeval(&tv, *timeoutp);
1.141 djm 264:
1.162 deraadt 265: for (;;) {
1.141 djm 266: rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
267: if (rc != -1 || errno != EINTR)
268: break;
269: }
270:
1.162 deraadt 271: switch (rc) {
1.141 djm 272: case 0:
273: /* Timed out */
274: errno = ETIMEDOUT;
1.142 djm 275: break;
1.141 djm 276: case -1:
277: /* Select error */
1.154 djm 278: debug("select: %s", strerror(errno));
1.142 djm 279: break;
1.141 djm 280: case 1:
281: /* Completed or failed */
282: optval = 0;
283: optlen = sizeof(optval);
1.154 djm 284: if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval,
1.148 markus 285: &optlen) == -1) {
1.154 djm 286: debug("getsockopt: %s", strerror(errno));
1.142 djm 287: break;
1.148 markus 288: }
1.141 djm 289: if (optval != 0) {
290: errno = optval;
1.142 djm 291: break;
1.141 djm 292: }
1.142 djm 293: result = 0;
1.156 djm 294: unset_nonblock(sockfd);
1.141 djm 295: break;
296: default:
297: /* Should not occur */
298: fatal("Bogus return (%d) from select()", rc);
299: }
300:
1.142 djm 301: xfree(fdset);
1.202 djm 302:
303: done:
304: if (result == 0 && *timeoutp > 0) {
305: ms_subtract_diff(&t_start, timeoutp);
306: if (*timeoutp <= 0) {
307: errno = ETIMEDOUT;
308: result = -1;
309: }
310: }
311:
1.142 djm 312: return (result);
1.141 djm 313: }
314:
1.39 deraadt 315: /*
1.49 markus 316: * Opens a TCP/IP connection to the remote server on the given host.
317: * The address of the remote host will be returned in hostaddr.
1.124 markus 318: * If port is 0, the default port will be used. If needpriv is true,
1.39 deraadt 319: * a privileged port will be allocated to make the connection.
1.124 markus 320: * This requires super-user privileges if needpriv is true.
1.39 deraadt 321: * Connection_attempts specifies the maximum number of tries (one per
322: * second). If proxy_command is non-NULL, it specifies the command (with %h
323: * and %p substituted for host and port, respectively) to use to contact
324: * the daemon.
325: */
1.38 markus 326: int
1.49 markus 327: ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
1.202 djm 328: u_short port, int family, int connection_attempts, int *timeout_ms,
329: int want_keepalive, int needpriv, const char *proxy_command)
1.1 deraadt 330: {
1.90 markus 331: int gaierr;
332: int on = 1;
1.49 markus 333: int sock = -1, attempt;
1.90 markus 334: char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1.49 markus 335: struct addrinfo hints, *ai, *aitop;
1.38 markus 336:
1.136 markus 337: debug2("ssh_connect: needpriv %d", needpriv);
1.38 markus 338:
339: /* If a proxy command is given, connect using it. */
340: if (proxy_command != NULL)
1.124 markus 341: return ssh_proxy_connect(host, port, proxy_command);
1.38 markus 342:
343: /* No proxy command. */
344:
1.49 markus 345: memset(&hints, 0, sizeof(hints));
1.115 markus 346: hints.ai_family = family;
1.49 markus 347: hints.ai_socktype = SOCK_STREAM;
1.126 deraadt 348: snprintf(strport, sizeof strport, "%u", port);
1.49 markus 349: if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
1.203 dtucker 350: fatal("%s: Could not resolve hostname %.100s: %s", __progname,
351: host, ssh_gai_strerror(gaierr));
1.38 markus 352:
1.181 markus 353: for (attempt = 0; attempt < connection_attempts; attempt++) {
1.200 markus 354: if (attempt > 0) {
355: /* Sleep a moment before retrying. */
356: sleep(1);
1.38 markus 357: debug("Trying again...");
1.200 markus 358: }
1.181 markus 359: /*
360: * Loop through addresses for this host, and try each one in
361: * sequence until the connection succeeds.
362: */
1.49 markus 363: for (ai = aitop; ai; ai = ai->ai_next) {
364: if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
365: continue;
366: if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
367: ntop, sizeof(ntop), strport, sizeof(strport),
368: NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
369: error("ssh_connect: getnameinfo failed");
370: continue;
371: }
372: debug("Connecting to %.200s [%.100s] port %s.",
373: host, ntop, strport);
374:
375: /* Create a socket for connecting. */
1.139 markus 376: sock = ssh_create_socket(needpriv, ai);
1.49 markus 377: if (sock < 0)
1.110 markus 378: /* Any error is already output */
1.49 markus 379: continue;
380:
1.141 djm 381: if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
1.202 djm 382: timeout_ms) >= 0) {
1.49 markus 383: /* Successful connection. */
1.102 markus 384: memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
1.38 markus 385: break;
1.49 markus 386: } else {
1.131 itojun 387: debug("connect to address %s port %s: %s",
388: ntop, strport, strerror(errno));
1.38 markus 389: close(sock);
1.181 markus 390: sock = -1;
1.38 markus 391: }
392: }
1.181 markus 393: if (sock != -1)
1.49 markus 394: break; /* Successful connection. */
1.38 markus 395: }
1.49 markus 396:
397: freeaddrinfo(aitop);
398:
1.38 markus 399: /* Return failure if we didn't get a successful connection. */
1.181 markus 400: if (sock == -1) {
1.159 markus 401: error("ssh: connect to host %s port %s: %s",
1.130 itojun 402: host, strport, strerror(errno));
1.159 markus 403: return (-1);
1.130 itojun 404: }
1.38 markus 405:
406: debug("Connection established.");
1.90 markus 407:
1.155 markus 408: /* Set SO_KEEPALIVE if requested. */
1.202 djm 409: if (want_keepalive &&
1.90 markus 410: setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
411: sizeof(on)) < 0)
412: error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1.38 markus 413:
414: /* Set the connection. */
415: packet_set_connection(sock, sock);
1.207 dtucker 416: packet_set_timeout(options.server_alive_interval,
417: options.server_alive_count_max);
1.1 deraadt 418:
1.110 markus 419: return 0;
1.59 markus 420: }
421:
1.43 markus 422: /*
1.39 deraadt 423: * Waits for the server identification string, and sends our own
424: * identification string.
425: */
1.213 andreas 426: void
1.202 djm 427: ssh_exchange_identification(int timeout_ms)
1.1 deraadt 428: {
1.38 markus 429: char buf[256], remote_version[256]; /* must be same size! */
1.165 djm 430: int remote_major, remote_minor, mismatch;
1.38 markus 431: int connection_in = packet_get_connection_in();
432: int connection_out = packet_get_connection_out();
1.93 stevesk 433: int minor1 = PROTOCOL_MINOR_1;
1.185 djm 434: u_int i, n;
1.202 djm 435: size_t len;
436: int fdsetsz, remaining, rc;
437: struct timeval t_start, t_remaining;
438: fd_set *fdset;
439:
440: fdsetsz = howmany(connection_in + 1, NFDBITS) * sizeof(fd_mask);
441: fdset = xcalloc(1, fdsetsz);
1.38 markus 442:
1.163 avsm 443: /* Read other side's version identification. */
1.202 djm 444: remaining = timeout_ms;
1.185 djm 445: for (n = 0;;) {
1.75 markus 446: for (i = 0; i < sizeof(buf) - 1; i++) {
1.202 djm 447: if (timeout_ms > 0) {
448: gettimeofday(&t_start, NULL);
449: ms_to_timeval(&t_remaining, remaining);
450: FD_SET(connection_in, fdset);
451: rc = select(connection_in + 1, fdset, NULL,
452: fdset, &t_remaining);
453: ms_subtract_diff(&t_start, &remaining);
454: if (rc == 0 || remaining <= 0)
455: fatal("Connection timed out during "
456: "banner exchange");
457: if (rc == -1) {
458: if (errno == EINTR)
459: continue;
460: fatal("ssh_exchange_identification: "
461: "select: %s", strerror(errno));
462: }
463: }
464:
1.214 andreas 465: len = roaming_atomicio(read, connection_in, &buf[i], 1);
1.163 avsm 466:
1.167 djm 467: if (len != 1 && errno == EPIPE)
1.202 djm 468: fatal("ssh_exchange_identification: "
469: "Connection closed by remote host");
1.163 avsm 470: else if (len != 1)
1.202 djm 471: fatal("ssh_exchange_identification: "
472: "read: %.100s", strerror(errno));
1.75 markus 473: if (buf[i] == '\r') {
474: buf[i] = '\n';
475: buf[i + 1] = 0;
476: continue; /**XXX wait for \n */
477: }
478: if (buf[i] == '\n') {
479: buf[i + 1] = 0;
480: break;
481: }
1.185 djm 482: if (++n > 65536)
1.202 djm 483: fatal("ssh_exchange_identification: "
484: "No banner received");
1.38 markus 485: }
1.75 markus 486: buf[sizeof(buf) - 1] = 0;
1.76 markus 487: if (strncmp(buf, "SSH-", 4) == 0)
1.38 markus 488: break;
1.75 markus 489: debug("ssh_exchange_identification: %s", buf);
1.38 markus 490: }
1.59 markus 491: server_version_string = xstrdup(buf);
1.202 djm 492: xfree(fdset);
1.38 markus 493:
1.40 markus 494: /*
495: * Check that the versions match. In future this might accept
496: * several versions and set appropriate flags to handle them.
497: */
1.59 markus 498: if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
499: &remote_major, &remote_minor, remote_version) != 3)
1.38 markus 500: fatal("Bad remote protocol version identification: '%.100s'", buf);
501: debug("Remote protocol version %d.%d, remote software version %.100s",
1.118 deraadt 502: remote_major, remote_minor, remote_version);
1.38 markus 503:
1.59 markus 504: compat_datafellows(remote_version);
1.64 markus 505: mismatch = 0;
1.59 markus 506:
1.116 deraadt 507: switch (remote_major) {
1.64 markus 508: case 1:
509: if (remote_minor == 99 &&
510: (options.protocol & SSH_PROTO_2) &&
511: !(options.protocol & SSH_PROTO_1_PREFERRED)) {
512: enable_compat20();
513: break;
514: }
515: if (!(options.protocol & SSH_PROTO_1)) {
516: mismatch = 1;
517: break;
518: }
519: if (remote_minor < 3) {
520: fatal("Remote machine has too old SSH software version.");
1.81 markus 521: } else if (remote_minor == 3 || remote_minor == 4) {
1.64 markus 522: /* We speak 1.3, too. */
523: enable_compat13();
1.81 markus 524: minor1 = 3;
1.64 markus 525: if (options.forward_agent) {
1.138 itojun 526: logit("Agent forwarding disabled for protocol 1.3");
1.64 markus 527: options.forward_agent = 0;
528: }
529: }
530: break;
531: case 2:
532: if (options.protocol & SSH_PROTO_2) {
533: enable_compat20();
534: break;
1.38 markus 535: }
1.64 markus 536: /* FALLTHROUGH */
1.68 markus 537: default:
1.64 markus 538: mismatch = 1;
539: break;
1.38 markus 540: }
1.64 markus 541: if (mismatch)
1.38 markus 542: fatal("Protocol major versions differ: %d vs. %d",
1.64 markus 543: (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
544: remote_major);
1.38 markus 545: /* Send our own protocol version identification. */
1.211 dtucker 546: snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s%s",
1.64 markus 547: compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
1.81 markus 548: compat20 ? PROTOCOL_MINOR_2 : minor1,
1.211 dtucker 549: SSH_VERSION, compat20 ? "\r\n" : "\n");
1.214 andreas 550: if (roaming_atomicio(vwrite, connection_out, buf, strlen(buf))
551: != strlen(buf))
1.38 markus 552: fatal("write: %.100s", strerror(errno));
1.59 markus 553: client_version_string = xstrdup(buf);
554: chop(client_version_string);
555: chop(server_version_string);
556: debug("Local version string %.100s", client_version_string);
1.1 deraadt 557: }
558:
1.96 markus 559: /* defaults to 'no' */
1.109 itojun 560: static int
1.112 markus 561: confirm(const char *prompt)
1.1 deraadt 562: {
1.119 markus 563: const char *msg, *again = "Please type 'yes' or 'no': ";
564: char *p;
565: int ret = -1;
1.96 markus 566:
567: if (options.batch_mode)
568: return 0;
1.119 markus 569: for (msg = prompt;;msg = again) {
570: p = read_passphrase(msg, RP_ECHO);
571: if (p == NULL ||
572: (p[0] == '\0') || (p[0] == '\n') ||
573: strncasecmp(p, "no", 2) == 0)
574: ret = 0;
1.127 markus 575: if (p && strncasecmp(p, "yes", 3) == 0)
1.119 markus 576: ret = 1;
577: if (p)
578: xfree(p);
579: if (ret != -1)
580: return ret;
1.1 deraadt 581: }
582: }
583:
1.219 djm 584: static int
585: check_host_cert(const char *host, const Key *host_key)
586: {
587: const char *reason;
588:
589: if (key_cert_check_authority(host_key, 1, 0, host, &reason) != 0) {
590: error("%s", reason);
591: return 0;
592: }
1.223 djm 593: if (buffer_len(&host_key->cert->critical) != 0) {
594: error("Certificate for %s contains unsupported "
595: "critical options(s)", host);
1.219 djm 596: return 0;
597: }
598: return 1;
599: }
600:
1.229 djm 601: static int
602: sockaddr_is_local(struct sockaddr *hostaddr)
603: {
604: switch (hostaddr->sa_family) {
605: case AF_INET:
606: return (ntohl(((struct sockaddr_in *)hostaddr)->
607: sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
608: case AF_INET6:
609: return IN6_IS_ADDR_LOOPBACK(
610: &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
611: default:
612: return 0;
613: }
614: }
615:
616: /*
617: * Prepare the hostname and ip address strings that are used to lookup
618: * host keys in known_hosts files. These may have a port number appended.
619: */
620: void
621: get_hostfile_hostname_ipaddr(char *hostname, struct sockaddr *hostaddr,
622: u_short port, char **hostfile_hostname, char **hostfile_ipaddr)
623: {
624: char ntop[NI_MAXHOST];
625:
626: /*
627: * We don't have the remote ip-address for connections
628: * using a proxy command
629: */
630: if (hostfile_ipaddr != NULL) {
631: if (options.proxy_command == NULL) {
632: if (getnameinfo(hostaddr, hostaddr->sa_len,
633: ntop, sizeof(ntop), NULL, 0, NI_NUMERICHOST) != 0)
634: fatal("check_host_key: getnameinfo failed");
635: *hostfile_ipaddr = put_host_port(ntop, port);
636: } else {
637: *hostfile_ipaddr = xstrdup("<no hostip for proxy "
638: "command>");
639: }
640: }
641:
642: /*
643: * Allow the user to record the key under a different name or
644: * differentiate a non-standard port. This is useful for ssh
645: * tunneling over forwarded connections or if you run multiple
646: * sshd's on different ports on the same machine.
647: */
648: if (hostfile_hostname != NULL) {
649: if (options.host_key_alias != NULL) {
650: *hostfile_hostname = xstrdup(options.host_key_alias);
651: debug("using hostkeyalias: %s", *hostfile_hostname);
652: } else {
653: *hostfile_hostname = put_host_port(hostname, port);
654: }
655: }
656: }
657:
1.39 deraadt 658: /*
1.108 markus 659: * check whether the supplied host key is valid, return -1 if the key
660: * is not valid. the user_hostfile will not be updated if 'readonly' is true.
1.39 deraadt 661: */
1.197 dtucker 662: #define RDRW 0
663: #define RDONLY 1
664: #define ROQUIET 2
1.109 itojun 665: static int
1.197 dtucker 666: check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port,
1.229 djm 667: Key *host_key, int readonly, char *user_hostfile,
668: char *system_hostfile)
1.1 deraadt 669: {
1.229 djm 670: Key *raw_key = NULL;
1.219 djm 671: const char *type;
1.189 dtucker 672: char *ip = NULL, *host = NULL;
1.204 grunk 673: char hostline[1000], *hostp, *fp, *ra;
1.38 markus 674: HostStatus host_status;
675: HostStatus ip_status;
1.229 djm 676: int r, want_cert = key_is_cert(host_key), host_ip_differ = 0;
677: int local = sockaddr_is_local(hostaddr);
1.119 markus 678: char msg[1024];
1.229 djm 679: int len, cancelled_forwarding = 0;
680: struct hostkeys *host_hostkeys, *ip_hostkeys;
681: const struct hostkey_entry *host_found, *ip_found;
1.49 markus 682:
683: /*
684: * Force accepting of the host key for loopback/localhost. The
685: * problem is that if the home directory is NFS-mounted to multiple
686: * machines, localhost will refer to a different machine in each of
687: * them, and the user will get bogus HOST_CHANGED warnings. This
688: * essentially disables host authentication for localhost; however,
689: * this is probably not a real problem.
690: */
1.111 markus 691: if (options.no_host_authentication_for_localhost == 1 && local &&
692: options.host_key_alias == NULL) {
1.88 markus 693: debug("Forcing accepting of host key for "
694: "loopback/localhost.");
1.108 markus 695: return 0;
1.49 markus 696: }
1.42 markus 697:
698: /*
1.229 djm 699: * Prepare the hostname and address strings used for hostkey lookup.
700: * In some cases, these will have a port number appended.
1.42 markus 701: */
1.229 djm 702: get_hostfile_hostname_ipaddr(hostname, hostaddr, port, &host, &ip);
1.206 grunk 703:
704: /*
1.88 markus 705: * Turn off check_host_ip if the connection is to localhost, via proxy
706: * command or if we don't have a hostname to compare with
707: */
1.189 dtucker 708: if (options.check_host_ip && (local ||
709: strcmp(hostname, ip) == 0 || options.proxy_command != NULL))
1.88 markus 710: options.check_host_ip = 0;
1.86 markus 711:
1.229 djm 712: host_hostkeys = init_hostkeys();
713: load_hostkeys(host_hostkeys, host, user_hostfile);
714: load_hostkeys(host_hostkeys, host, system_hostfile);
715:
716: ip_hostkeys = NULL;
717: if (!want_cert && options.check_host_ip) {
718: ip_hostkeys = init_hostkeys();
719: load_hostkeys(ip_hostkeys, ip, user_hostfile);
720: load_hostkeys(ip_hostkeys, ip, system_hostfile);
1.84 markus 721: }
1.38 markus 722:
1.219 djm 723: retry:
1.229 djm 724: /* Reload these as they may have changed on cert->key downgrade */
1.219 djm 725: want_cert = key_is_cert(host_key);
726: type = key_type(host_key);
727:
1.46 markus 728: /*
1.170 djm 729: * Check if the host key is present in the user's list of known
1.40 markus 730: * hosts or in the systemwide list.
731: */
1.229 djm 732: host_status = check_key_in_hostkeys(host_hostkeys, host_key,
733: &host_found);
734:
1.40 markus 735: /*
736: * Also perform check for the ip address, skip the check if we are
1.219 djm 737: * localhost, looking for a certificate, or the hostname was an ip
738: * address to begin with.
1.40 markus 739: */
1.229 djm 740: if (!want_cert && ip_hostkeys != NULL) {
741: ip_status = check_key_in_hostkeys(ip_hostkeys, host_key,
742: &ip_found);
1.38 markus 743: if (host_status == HOST_CHANGED &&
1.229 djm 744: (ip_status != HOST_CHANGED ||
745: (ip_found != NULL &&
746: !key_equal(ip_found->key, host_found->key))))
1.38 markus 747: host_ip_differ = 1;
748: } else
749: ip_status = host_status;
750:
751: switch (host_status) {
752: case HOST_OK:
753: /* The host is known and the key matches. */
1.219 djm 754: debug("Host '%.200s' is known and matches the %s host %s.",
755: host, type, want_cert ? "certificate" : "key");
1.229 djm 756: debug("Found %s in %s:%lu", want_cert ? "CA key" : "key",
757: host_found->file, host_found->line);
1.219 djm 758: if (want_cert && !check_host_cert(hostname, host_key))
759: goto fail;
1.88 markus 760: if (options.check_host_ip && ip_status == HOST_NEW) {
1.219 djm 761: if (readonly || want_cert)
1.138 itojun 762: logit("%s host key for IP address "
1.108 markus 763: "'%.128s' not in list of known hosts.",
764: type, ip);
765: else if (!add_host_to_hostfile(user_hostfile, ip,
1.160 djm 766: host_key, options.hash_known_hosts))
1.138 itojun 767: logit("Failed to add the %s host key for IP "
1.108 markus 768: "address '%.128s' to the list of known "
769: "hosts (%.30s).", type, ip, user_hostfile);
1.88 markus 770: else
1.138 itojun 771: logit("Warning: Permanently added the %s host "
1.108 markus 772: "key for IP address '%.128s' to the list "
773: "of known hosts.", type, ip);
1.209 grunk 774: } else if (options.visual_host_key) {
1.204 grunk 775: fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
776: ra = key_fingerprint(host_key, SSH_FP_MD5,
777: SSH_FP_RANDOMART);
778: logit("Host key fingerprint is %s\n%s\n", fp, ra);
779: xfree(ra);
780: xfree(fp);
1.38 markus 781: }
782: break;
783: case HOST_NEW:
1.197 dtucker 784: if (options.host_key_alias == NULL && port != 0 &&
785: port != SSH_DEFAULT_PORT) {
786: debug("checking without port identifier");
1.212 stevesk 787: if (check_host_key(hostname, hostaddr, 0, host_key,
788: ROQUIET, user_hostfile, system_hostfile) == 0) {
1.197 dtucker 789: debug("found matching key w/out port");
790: break;
791: }
792: }
1.219 djm 793: if (readonly || want_cert)
1.108 markus 794: goto fail;
1.38 markus 795: /* The host is new. */
796: if (options.strict_host_key_checking == 1) {
1.108 markus 797: /*
798: * User has requested strict host key checking. We
799: * will not add the host key automatically. The only
800: * alternative left is to abort.
801: */
802: error("No %s host key is known for %.200s and you "
803: "have requested strict checking.", type, host);
804: goto fail;
1.38 markus 805: } else if (options.strict_host_key_checking == 2) {
1.145 jakob 806: char msg1[1024], msg2[1024];
807:
1.229 djm 808: if (show_other_keys(host_hostkeys, host_key))
1.145 jakob 809: snprintf(msg1, sizeof(msg1),
1.168 djm 810: "\nbut keys of different type are already"
811: " known for this host.");
1.145 jakob 812: else
813: snprintf(msg1, sizeof(msg1), ".");
1.38 markus 814: /* The default */
1.100 markus 815: fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1.204 grunk 816: ra = key_fingerprint(host_key, SSH_FP_MD5,
817: SSH_FP_RANDOMART);
1.145 jakob 818: msg2[0] = '\0';
819: if (options.verify_host_key_dns) {
1.153 jakob 820: if (matching_host_key_dns)
1.145 jakob 821: snprintf(msg2, sizeof(msg2),
822: "Matching host key fingerprint"
823: " found in DNS.\n");
824: else
825: snprintf(msg2, sizeof(msg2),
826: "No matching host key fingerprint"
827: " found in DNS.\n");
828: }
1.119 markus 829: snprintf(msg, sizeof(msg),
1.108 markus 830: "The authenticity of host '%.200s (%s)' can't be "
1.132 markus 831: "established%s\n"
1.209 grunk 832: "%s key fingerprint is %s.%s%s\n%s"
1.108 markus 833: "Are you sure you want to continue connecting "
1.132 markus 834: "(yes/no)? ",
1.209 grunk 835: host, ip, msg1, type, fp,
836: options.visual_host_key ? "\n" : "",
837: options.visual_host_key ? ra : "",
838: msg2);
1.204 grunk 839: xfree(ra);
1.100 markus 840: xfree(fp);
1.119 markus 841: if (!confirm(msg))
1.108 markus 842: goto fail;
1.38 markus 843: }
1.161 djm 844: /*
845: * If not in strict mode, add the key automatically to the
846: * local known_hosts file.
847: */
1.88 markus 848: if (options.check_host_ip && ip_status == HOST_NEW) {
1.229 djm 849: snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
1.38 markus 850: hostp = hostline;
1.161 djm 851: if (options.hash_known_hosts) {
852: /* Add hash of host and IP separately */
853: r = add_host_to_hostfile(user_hostfile, host,
854: host_key, options.hash_known_hosts) &&
855: add_host_to_hostfile(user_hostfile, ip,
856: host_key, options.hash_known_hosts);
857: } else {
858: /* Add unhashed "host,ip" */
859: r = add_host_to_hostfile(user_hostfile,
860: hostline, host_key,
861: options.hash_known_hosts);
862: }
863: } else {
864: r = add_host_to_hostfile(user_hostfile, host, host_key,
865: options.hash_known_hosts);
1.38 markus 866: hostp = host;
1.161 djm 867: }
1.38 markus 868:
1.161 djm 869: if (!r)
1.138 itojun 870: logit("Failed to add the host to the list of known "
1.108 markus 871: "hosts (%.500s).", user_hostfile);
1.38 markus 872: else
1.138 itojun 873: logit("Warning: Permanently added '%.200s' (%s) to the "
1.108 markus 874: "list of known hosts.", hostp, type);
1.38 markus 875: break;
1.220 djm 876: case HOST_REVOKED:
877: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
878: error("@ WARNING: REVOKED HOST KEY DETECTED! @");
879: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
880: error("The %s host key for %s is marked as revoked.", type, host);
881: error("This could mean that a stolen key is being used to");
882: error("impersonate this host.");
883:
884: /*
885: * If strict host key checking is in use, the user will have
886: * to edit the key manually and we can only abort.
887: */
888: if (options.strict_host_key_checking) {
889: error("%s host key for %.200s was revoked and you have "
890: "requested strict checking.", type, host);
891: goto fail;
892: }
893: goto continue_unsafe;
894:
1.38 markus 895: case HOST_CHANGED:
1.219 djm 896: if (want_cert) {
897: /*
898: * This is only a debug() since it is valid to have
899: * CAs with wildcard DNS matches that don't match
900: * all hosts that one might visit.
901: */
902: debug("Host certificate authority does not "
1.229 djm 903: "match %s in %s:%lu", CA_MARKER,
904: host_found->file, host_found->line);
1.219 djm 905: goto fail;
906: }
1.197 dtucker 907: if (readonly == ROQUIET)
908: goto fail;
1.38 markus 909: if (options.check_host_ip && host_ip_differ) {
1.158 avsm 910: char *key_msg;
1.38 markus 911: if (ip_status == HOST_NEW)
1.158 avsm 912: key_msg = "is unknown";
1.38 markus 913: else if (ip_status == HOST_OK)
1.158 avsm 914: key_msg = "is unchanged";
1.38 markus 915: else
1.158 avsm 916: key_msg = "has a different value";
1.38 markus 917: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
918: error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
919: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1.72 markus 920: error("The %s host key for %s has changed,", type, host);
1.208 ian 921: error("and the key for the corresponding IP address %s", ip);
1.158 avsm 922: error("%s. This could either mean that", key_msg);
1.38 markus 923: error("DNS SPOOFING is happening or the IP address for the host");
1.85 markus 924: error("and its host key have changed at the same time.");
1.88 markus 925: if (ip_status != HOST_NEW)
1.229 djm 926: error("Offending key for IP in %s:%lu",
927: ip_found->file, ip_found->line);
1.38 markus 928: }
929: /* The host key has changed. */
1.150 jakob 930: warn_changed_key(host_key);
1.38 markus 931: error("Add correct host key in %.100s to get rid of this message.",
1.87 markus 932: user_hostfile);
1.229 djm 933: error("Offending %s key in %s:%lu", key_type(host_found->key),
934: host_found->file, host_found->line);
1.38 markus 935:
1.40 markus 936: /*
937: * If strict host key checking is in use, the user will have
938: * to edit the key manually and we can only abort.
939: */
1.108 markus 940: if (options.strict_host_key_checking) {
941: error("%s host key for %.200s has changed and you have "
942: "requested strict checking.", type, host);
943: goto fail;
944: }
1.38 markus 945:
1.220 djm 946: continue_unsafe:
1.40 markus 947: /*
948: * If strict host key checking has not been requested, allow
1.144 djm 949: * the connection but without MITM-able authentication or
1.194 stevesk 950: * forwarding.
1.40 markus 951: */
1.38 markus 952: if (options.password_authentication) {
1.108 markus 953: error("Password authentication is disabled to avoid "
954: "man-in-the-middle attacks.");
1.38 markus 955: options.password_authentication = 0;
1.210 dtucker 956: cancelled_forwarding = 1;
1.144 djm 957: }
958: if (options.kbd_interactive_authentication) {
959: error("Keyboard-interactive authentication is disabled"
960: " to avoid man-in-the-middle attacks.");
961: options.kbd_interactive_authentication = 0;
962: options.challenge_response_authentication = 0;
1.210 dtucker 963: cancelled_forwarding = 1;
1.144 djm 964: }
965: if (options.challenge_response_authentication) {
966: error("Challenge/response authentication is disabled"
967: " to avoid man-in-the-middle attacks.");
968: options.challenge_response_authentication = 0;
1.210 dtucker 969: cancelled_forwarding = 1;
1.38 markus 970: }
971: if (options.forward_agent) {
1.108 markus 972: error("Agent forwarding is disabled to avoid "
973: "man-in-the-middle attacks.");
1.38 markus 974: options.forward_agent = 0;
1.210 dtucker 975: cancelled_forwarding = 1;
1.83 markus 976: }
977: if (options.forward_x11) {
1.108 markus 978: error("X11 forwarding is disabled to avoid "
979: "man-in-the-middle attacks.");
1.83 markus 980: options.forward_x11 = 0;
1.210 dtucker 981: cancelled_forwarding = 1;
1.83 markus 982: }
1.108 markus 983: if (options.num_local_forwards > 0 ||
984: options.num_remote_forwards > 0) {
985: error("Port forwarding is disabled to avoid "
986: "man-in-the-middle attacks.");
987: options.num_local_forwards =
1.118 deraadt 988: options.num_remote_forwards = 0;
1.210 dtucker 989: cancelled_forwarding = 1;
1.194 stevesk 990: }
991: if (options.tun_open != SSH_TUNMODE_NO) {
992: error("Tunnel forwarding is disabled to avoid "
993: "man-in-the-middle attacks.");
994: options.tun_open = SSH_TUNMODE_NO;
1.210 dtucker 995: cancelled_forwarding = 1;
1.38 markus 996: }
1.210 dtucker 997: if (options.exit_on_forward_failure && cancelled_forwarding)
998: fatal("Error: forwarding disabled due to host key "
999: "check failure");
1000:
1.40 markus 1001: /*
1002: * XXX Should permit the user to change to use the new id.
1003: * This could be done by converting the host key to an
1004: * identifying sentence, tell that the host identifies itself
1.218 dtucker 1005: * by that sentence, and ask the user if he/she wishes to
1.40 markus 1006: * accept the authentication.
1007: */
1.38 markus 1008: break;
1.132 markus 1009: case HOST_FOUND:
1010: fatal("internal error");
1011: break;
1.88 markus 1012: }
1013:
1014: if (options.check_host_ip && host_status != HOST_CHANGED &&
1015: ip_status == HOST_CHANGED) {
1.119 markus 1016: snprintf(msg, sizeof(msg),
1017: "Warning: the %s host key for '%.200s' "
1018: "differs from the key for the IP address '%.128s'"
1.229 djm 1019: "\nOffending key for IP in %s:%lu",
1020: type, host, ip, ip_found->file, ip_found->line);
1.119 markus 1021: if (host_status == HOST_OK) {
1022: len = strlen(msg);
1023: snprintf(msg + len, sizeof(msg) - len,
1.229 djm 1024: "\nMatching host key in %s:%lu",
1025: host_found->file, host_found->line);
1.119 markus 1026: }
1.88 markus 1027: if (options.strict_host_key_checking == 1) {
1.143 djm 1028: logit("%s", msg);
1.108 markus 1029: error("Exiting, you have requested strict checking.");
1030: goto fail;
1.88 markus 1031: } else if (options.strict_host_key_checking == 2) {
1.119 markus 1032: strlcat(msg, "\nAre you sure you want "
1033: "to continue connecting (yes/no)? ", sizeof(msg));
1034: if (!confirm(msg))
1.108 markus 1035: goto fail;
1.119 markus 1036: } else {
1.143 djm 1037: logit("%s", msg);
1.88 markus 1038: }
1.38 markus 1039: }
1.82 provos 1040:
1041: xfree(ip);
1.189 dtucker 1042: xfree(host);
1.229 djm 1043: if (host_hostkeys != NULL)
1044: free_hostkeys(host_hostkeys);
1045: if (ip_hostkeys != NULL)
1046: free_hostkeys(ip_hostkeys);
1.108 markus 1047: return 0;
1048:
1049: fail:
1.220 djm 1050: if (want_cert && host_status != HOST_REVOKED) {
1.219 djm 1051: /*
1052: * No matching certificate. Downgrade cert to raw key and
1053: * search normally.
1054: */
1055: debug("No matching CA found. Retry with plain key");
1056: raw_key = key_from_private(host_key);
1057: if (key_drop_cert(raw_key) != 0)
1058: fatal("Couldn't drop certificate");
1059: host_key = raw_key;
1060: goto retry;
1061: }
1062: if (raw_key != NULL)
1063: key_free(raw_key);
1.108 markus 1064: xfree(ip);
1.189 dtucker 1065: xfree(host);
1.229 djm 1066: if (host_hostkeys != NULL)
1067: free_hostkeys(host_hostkeys);
1068: if (ip_hostkeys != NULL)
1069: free_hostkeys(ip_hostkeys);
1.108 markus 1070: return -1;
1071: }
1072:
1.140 jakob 1073: /* returns 0 if key verifies or -1 if key does NOT verify */
1.108 markus 1074: int
1075: verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
1076: {
1077: struct stat st;
1.153 jakob 1078: int flags = 0;
1.229 djm 1079: char *fp;
1080:
1081: fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1082: debug("Server host key: %s %s", key_type(host_key), fp);
1083: xfree(fp);
1.140 jakob 1084:
1.219 djm 1085: /* XXX certs are not yet supported for DNS */
1086: if (!key_is_cert(host_key) && options.verify_host_key_dns &&
1.153 jakob 1087: verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
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;
1.231 djm 1236: void (*osighand)(int);
1.171 reyk 1237:
1238: if (!options.permit_local_command ||
1239: args == NULL || !*args)
1240: return (1);
1241:
1.226 djm 1242: if ((shell = getenv("SHELL")) == NULL || *shell == '\0')
1.171 reyk 1243: shell = _PATH_BSHELL;
1244:
1.231 djm 1245: osighand = signal(SIGCHLD, SIG_DFL);
1.171 reyk 1246: pid = fork();
1247: if (pid == 0) {
1.232 djm 1248: signal(SIGPIPE, SIG_DFL);
1.171 reyk 1249: debug3("Executing %s -c \"%s\"", shell, args);
1250: execl(shell, shell, "-c", args, (char *)NULL);
1251: error("Couldn't execute %s -c \"%s\": %s",
1252: shell, args, strerror(errno));
1253: _exit(1);
1254: } else if (pid == -1)
1255: fatal("fork failed: %.100s", strerror(errno));
1256: while (waitpid(pid, &status, 0) == -1)
1257: if (errno != EINTR)
1258: fatal("Couldn't wait for child: %s", strerror(errno));
1.231 djm 1259: signal(SIGCHLD, osighand);
1.171 reyk 1260:
1261: if (!WIFEXITED(status))
1262: return (1);
1263:
1264: return (WEXITSTATUS(status));
1.1 deraadt 1265: }
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