Annotation of src/usr.bin/ssh/sshconnect.c, Revision 1.368
1.368 ! djm 1: /* $OpenBSD: sshconnect.c,v 1.367 2024/04/23 13:34:50 jsg 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:
1.295 djm 22: #include <net/if.h>
1.187 stevesk 23: #include <netinet/in.h>
1.172 stevesk 24:
1.176 stevesk 25: #include <ctype.h>
1.190 stevesk 26: #include <errno.h>
1.216 dtucker 27: #include <fcntl.h>
1.191 stevesk 28: #include <netdb.h>
1.345 djm 29: #include <limits.h>
1.172 stevesk 30: #include <paths.h>
1.199 deraadt 31: #include <signal.h>
1.188 stevesk 32: #include <pwd.h>
1.198 stevesk 33: #include <stdio.h>
1.196 stevesk 34: #include <stdlib.h>
1.323 deraadt 35: #include <stdarg.h>
1.193 stevesk 36: #include <string.h>
1.192 stevesk 37: #include <unistd.h>
1.295 djm 38: #include <ifaddrs.h>
1.71 markus 39:
1.199 deraadt 40: #include "xmalloc.h"
1.91 markus 41: #include "ssh.h"
1.299 markus 42: #include "sshbuf.h"
1.1 deraadt 43: #include "packet.h"
1.300 markus 44: #include "sshkey.h"
1.71 markus 45: #include "sshconnect.h"
1.58 markus 46: #include "hostfile.h"
1.91 markus 47: #include "log.h"
1.368 ! djm 48: #include "match.h"
1.251 millert 49: #include "misc.h"
1.91 markus 50: #include "readconf.h"
51: #include "atomicio.h"
1.140 jakob 52: #include "dns.h"
1.239 djm 53: #include "monitor_fdpass.h"
1.219 djm 54: #include "ssh2.h"
1.186 stevesk 55: #include "version.h"
1.252 djm 56: #include "authfile.h"
57: #include "ssherr.h"
1.266 jcs 58: #include "authfd.h"
1.309 djm 59: #include "kex.h"
1.310 djm 60:
1.279 markus 61: struct sshkey *previous_host_key = NULL;
1.59 markus 62:
1.169 stevesk 63: static int matching_host_key_dns = 0;
1.145 jakob 64:
1.227 djm 65: static pid_t proxy_command_pid = 0;
66:
1.124 markus 67: /* import */
1.307 djm 68: extern int debug_flag;
1.43 markus 69: extern Options options;
1.50 markus 70: extern char *__progname;
1.91 markus 71:
1.279 markus 72: static int show_other_keys(struct hostkeys *, struct sshkey *);
73: static void warn_changed_key(struct sshkey *);
1.132 markus 74:
1.239 djm 75: /* Expand a proxy command */
76: static char *
77: expand_proxy_command(const char *proxy_command, const char *user,
1.325 naddy 78: const char *host, const char *host_arg, int port)
1.239 djm 79: {
80: char *tmp, *ret, strport[NI_MAXSERV];
1.330 dtucker 81: const char *keyalias = options.host_key_alias ?
1.352 djm 82: options.host_key_alias : host_arg;
1.239 djm 83:
1.241 djm 84: snprintf(strport, sizeof strport, "%d", port);
1.239 djm 85: xasprintf(&tmp, "exec %s", proxy_command);
1.318 djm 86: ret = percent_expand(tmp,
87: "h", host,
1.330 dtucker 88: "k", keyalias,
1.318 djm 89: "n", host_arg,
90: "p", strport,
91: "r", options.user,
92: (char *)NULL);
1.239 djm 93: free(tmp);
94: return ret;
95: }
96:
97: /*
98: * Connect to the given ssh server using a proxy command that passes a
99: * a connected fd back to us.
100: */
101: static int
1.318 djm 102: ssh_proxy_fdpass_connect(struct ssh *ssh, const char *host,
103: const char *host_arg, u_short port, const char *proxy_command)
1.239 djm 104: {
105: char *command_string;
106: int sp[2], sock;
107: pid_t pid;
108: char *shell;
109:
110: if ((shell = getenv("SHELL")) == NULL)
111: shell = _PATH_BSHELL;
112:
1.317 deraadt 113: if (socketpair(AF_UNIX, SOCK_STREAM, 0, sp) == -1)
1.239 djm 114: fatal("Could not create socketpair to communicate with "
115: "proxy dialer: %.100s", strerror(errno));
116:
117: command_string = expand_proxy_command(proxy_command, options.user,
1.325 naddy 118: host, host_arg, port);
1.239 djm 119: debug("Executing proxy dialer command: %.500s", command_string);
120:
121: /* Fork and execute the proxy command. */
122: if ((pid = fork()) == 0) {
123: char *argv[10];
124:
125: close(sp[1]);
126: /* Redirect stdin and stdout. */
127: if (sp[0] != 0) {
1.317 deraadt 128: if (dup2(sp[0], 0) == -1)
1.239 djm 129: perror("dup2 stdin");
130: }
131: if (sp[0] != 1) {
1.317 deraadt 132: if (dup2(sp[0], 1) == -1)
1.239 djm 133: perror("dup2 stdout");
134: }
135: if (sp[0] >= 2)
136: close(sp[0]);
137:
138: /*
1.307 djm 139: * Stderr is left for non-ControlPersist connections is so
140: * error messages may be printed on the user's terminal.
1.239 djm 141: */
1.308 dtucker 142: if (!debug_flag && options.control_path != NULL &&
1.334 djm 143: options.control_persist && stdfd_devnull(0, 0, 1) == -1)
1.341 djm 144: error_f("stdfd_devnull failed");
1.307 djm 145:
1.239 djm 146: argv[0] = shell;
147: argv[1] = "-c";
148: argv[2] = command_string;
149: argv[3] = NULL;
150:
151: /*
152: * Execute the proxy command.
153: * Note that we gave up any extra privileges above.
154: */
155: execv(argv[0], argv);
156: perror(argv[0]);
157: exit(1);
158: }
159: /* Parent. */
1.317 deraadt 160: if (pid == -1)
1.239 djm 161: fatal("fork failed: %.100s", strerror(errno));
162: close(sp[0]);
163: free(command_string);
164:
165: if ((sock = mm_receive_fd(sp[1])) == -1)
166: fatal("proxy dialer did not pass back a connection");
1.271 markus 167: close(sp[1]);
1.239 djm 168:
169: while (waitpid(pid, NULL, 0) == -1)
170: if (errno != EINTR)
171: fatal("Couldn't wait for child: %s", strerror(errno));
172:
173: /* Set the connection file descriptors. */
1.286 djm 174: if (ssh_packet_set_connection(ssh, sock, sock) == NULL)
175: return -1; /* ssh_packet_set_connection logs error */
1.239 djm 176:
177: return 0;
178: }
179:
1.39 deraadt 180: /*
181: * Connect to the given ssh server using a proxy command.
182: */
1.109 itojun 183: static int
1.318 djm 184: ssh_proxy_connect(struct ssh *ssh, const char *host, const char *host_arg,
185: u_short port, const char *proxy_command)
1.1 deraadt 186: {
1.239 djm 187: char *command_string;
1.38 markus 188: int pin[2], pout[2];
1.69 deraadt 189: pid_t pid;
1.239 djm 190: char *shell;
1.237 markus 191:
1.226 djm 192: if ((shell = getenv("SHELL")) == NULL || *shell == '\0')
1.201 djm 193: shell = _PATH_BSHELL;
1.38 markus 194:
195: /* Create pipes for communicating with the proxy. */
1.317 deraadt 196: if (pipe(pin) == -1 || pipe(pout) == -1)
1.38 markus 197: fatal("Could not create pipes to communicate with the proxy: %.100s",
1.118 deraadt 198: strerror(errno));
1.38 markus 199:
1.239 djm 200: command_string = expand_proxy_command(proxy_command, options.user,
1.325 naddy 201: host, host_arg, port);
1.38 markus 202: debug("Executing proxy command: %.500s", command_string);
203:
204: /* Fork and execute the proxy command. */
205: if ((pid = fork()) == 0) {
206: char *argv[10];
207:
208: /* Redirect stdin and stdout. */
209: close(pin[1]);
210: if (pin[0] != 0) {
1.317 deraadt 211: if (dup2(pin[0], 0) == -1)
1.38 markus 212: perror("dup2 stdin");
213: close(pin[0]);
214: }
215: close(pout[0]);
1.317 deraadt 216: if (dup2(pout[1], 1) == -1)
1.38 markus 217: perror("dup2 stdout");
218: /* Cannot be 1 because pin allocated two descriptors. */
219: close(pout[1]);
220:
1.307 djm 221: /*
222: * Stderr is left for non-ControlPersist connections is so
223: * error messages may be printed on the user's terminal.
224: */
1.308 dtucker 225: if (!debug_flag && options.control_path != NULL &&
1.334 djm 226: options.control_persist && stdfd_devnull(0, 0, 1) == -1)
1.341 djm 227: error_f("stdfd_devnull failed");
1.307 djm 228:
1.201 djm 229: argv[0] = shell;
1.38 markus 230: argv[1] = "-c";
231: argv[2] = command_string;
232: argv[3] = NULL;
233:
1.352 djm 234: /*
235: * Execute the proxy command. Note that we gave up any
236: * extra privileges above.
237: */
1.327 dtucker 238: ssh_signal(SIGPIPE, SIG_DFL);
1.89 markus 239: execv(argv[0], argv);
240: perror(argv[0]);
1.38 markus 241: exit(1);
242: }
243: /* Parent. */
1.317 deraadt 244: if (pid == -1)
1.38 markus 245: fatal("fork failed: %.100s", strerror(errno));
1.135 djm 246: else
247: proxy_command_pid = pid; /* save pid to clean up later */
1.38 markus 248:
249: /* Close child side of the descriptors. */
250: close(pin[0]);
251: close(pout[1]);
252:
253: /* Free the command name. */
1.238 djm 254: free(command_string);
1.38 markus 255:
256: /* Set the connection file descriptors. */
1.286 djm 257: if (ssh_packet_set_connection(ssh, pout[0], pin[1]) == NULL)
258: return -1; /* ssh_packet_set_connection logs error */
1.1 deraadt 259:
1.110 markus 260: return 0;
1.227 djm 261: }
262:
263: void
264: ssh_kill_proxy_command(void)
265: {
266: /*
267: * Send SIGHUP to proxy command if used. We don't wait() in
268: * case it hangs and instead rely on init to reap the child
269: */
270: if (proxy_command_pid > 1)
1.228 djm 271: kill(proxy_command_pid, SIGHUP);
1.1 deraadt 272: }
273:
1.39 deraadt 274: /*
1.295 djm 275: * Search a interface address list (returned from getifaddrs(3)) for an
1.298 djm 276: * address that matches the desired address family on the specified interface.
1.295 djm 277: * Returns 0 and fills in *resultp and *rlenp on success. Returns -1 on failure.
278: */
279: static int
280: check_ifaddrs(const char *ifname, int af, const struct ifaddrs *ifaddrs,
281: struct sockaddr_storage *resultp, socklen_t *rlenp)
282: {
283: struct sockaddr_in6 *sa6;
284: struct sockaddr_in *sa;
285: struct in6_addr *v6addr;
286: const struct ifaddrs *ifa;
287: int allow_local;
288:
289: /*
290: * Prefer addresses that are not loopback or linklocal, but use them
291: * if nothing else matches.
292: */
293: for (allow_local = 0; allow_local < 2; allow_local++) {
294: for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
295: if (ifa->ifa_addr == NULL || ifa->ifa_name == NULL ||
296: (ifa->ifa_flags & IFF_UP) == 0 ||
297: ifa->ifa_addr->sa_family != af ||
298: strcmp(ifa->ifa_name, options.bind_interface) != 0)
299: continue;
300: switch (ifa->ifa_addr->sa_family) {
301: case AF_INET:
302: sa = (struct sockaddr_in *)ifa->ifa_addr;
303: if (!allow_local && sa->sin_addr.s_addr ==
304: htonl(INADDR_LOOPBACK))
305: continue;
306: if (*rlenp < sizeof(struct sockaddr_in)) {
1.341 djm 307: error_f("v4 addr doesn't fit");
1.295 djm 308: return -1;
309: }
310: *rlenp = sizeof(struct sockaddr_in);
311: memcpy(resultp, sa, *rlenp);
312: return 0;
313: case AF_INET6:
314: sa6 = (struct sockaddr_in6 *)ifa->ifa_addr;
315: v6addr = &sa6->sin6_addr;
316: if (!allow_local &&
317: (IN6_IS_ADDR_LINKLOCAL(v6addr) ||
318: IN6_IS_ADDR_LOOPBACK(v6addr)))
319: continue;
320: if (*rlenp < sizeof(struct sockaddr_in6)) {
1.341 djm 321: error_f("v6 addr doesn't fit");
1.295 djm 322: return -1;
323: }
324: *rlenp = sizeof(struct sockaddr_in6);
325: memcpy(resultp, sa6, *rlenp);
326: return 0;
327: }
328: }
329: }
330: return -1;
331: }
332:
333: /*
1.303 dtucker 334: * Creates a socket for use as the ssh connection.
1.39 deraadt 335: */
1.109 itojun 336: static int
1.302 dtucker 337: ssh_create_socket(struct addrinfo *ai)
1.1 deraadt 338: {
1.301 dtucker 339: int sock, r;
1.295 djm 340: struct sockaddr_storage bindaddr;
341: socklen_t bindaddrlen = 0;
1.246 djm 342: struct addrinfo hints, *res = NULL;
1.295 djm 343: struct ifaddrs *ifaddrs = NULL;
344: char ntop[NI_MAXHOST];
1.1 deraadt 345:
1.217 dtucker 346: sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
1.317 deraadt 347: if (sock == -1) {
1.240 djm 348: error("socket: %s", strerror(errno));
1.216 dtucker 349: return -1;
350: }
1.363 dtucker 351: (void)fcntl(sock, F_SETFD, FD_CLOEXEC);
1.345 djm 352:
353: /* Use interactive QOS (if specified) until authentication completed */
354: if (options.ip_qos_interactive != INT_MAX)
355: set_sock_tos(sock, options.ip_qos_interactive);
1.105 markus 356:
357: /* Bind the socket to an alternative local IP address */
1.302 dtucker 358: if (options.bind_address == NULL && options.bind_interface == NULL)
1.105 markus 359: return sock;
360:
1.295 djm 361: if (options.bind_address != NULL) {
1.246 djm 362: memset(&hints, 0, sizeof(hints));
363: hints.ai_family = ai->ai_family;
364: hints.ai_socktype = ai->ai_socktype;
365: hints.ai_protocol = ai->ai_protocol;
366: hints.ai_flags = AI_PASSIVE;
1.295 djm 367: if ((r = getaddrinfo(options.bind_address, NULL,
368: &hints, &res)) != 0) {
1.246 djm 369: error("getaddrinfo: %s: %s", options.bind_address,
1.295 djm 370: ssh_gai_strerror(r));
371: goto fail;
372: }
1.296 dtucker 373: if (res == NULL) {
1.295 djm 374: error("getaddrinfo: no addrs");
375: goto fail;
376: }
377: memcpy(&bindaddr, res->ai_addr, res->ai_addrlen);
378: bindaddrlen = res->ai_addrlen;
379: } else if (options.bind_interface != NULL) {
380: if ((r = getifaddrs(&ifaddrs)) != 0) {
381: error("getifaddrs: %s: %s", options.bind_interface,
1.352 djm 382: strerror(errno));
1.295 djm 383: goto fail;
384: }
385: bindaddrlen = sizeof(bindaddr);
386: if (check_ifaddrs(options.bind_interface, ai->ai_family,
387: ifaddrs, &bindaddr, &bindaddrlen) != 0) {
388: logit("getifaddrs: %s: no suitable addresses",
1.352 djm 389: options.bind_interface);
1.295 djm 390: goto fail;
1.246 djm 391: }
1.105 markus 392: }
1.295 djm 393: if ((r = getnameinfo((struct sockaddr *)&bindaddr, bindaddrlen,
394: ntop, sizeof(ntop), NULL, 0, NI_NUMERICHOST)) != 0) {
1.341 djm 395: error_f("getnameinfo failed: %s", ssh_gai_strerror(r));
1.295 djm 396: goto fail;
397: }
1.301 dtucker 398: if (bind(sock, (struct sockaddr *)&bindaddr, bindaddrlen) != 0) {
1.295 djm 399: error("bind %s: %s", ntop, strerror(errno));
400: goto fail;
1.38 markus 401: }
1.341 djm 402: debug_f("bound to %s", ntop);
1.295 djm 403: /* success */
404: goto out;
405: fail:
406: close(sock);
407: sock = -1;
408: out:
1.246 djm 409: if (res != NULL)
410: freeaddrinfo(res);
1.295 djm 411: if (ifaddrs != NULL)
412: freeifaddrs(ifaddrs);
1.38 markus 413: return sock;
1.1 deraadt 414: }
415:
1.282 djm 416: /*
1.49 markus 417: * Opens a TCP/IP connection to the remote server on the given host.
418: * The address of the remote host will be returned in hostaddr.
1.302 dtucker 419: * If port is 0, the default port will be used.
1.39 deraadt 420: * Connection_attempts specifies the maximum number of tries (one per
421: * second). If proxy_command is non-NULL, it specifies the command (with %h
422: * and %p substituted for host and port, respectively) to use to contact
423: * the daemon.
424: */
1.241 djm 425: static int
1.286 djm 426: ssh_connect_direct(struct ssh *ssh, const char *host, struct addrinfo *aitop,
1.340 kn 427: struct sockaddr_storage *hostaddr, u_short port, int connection_attempts,
428: int *timeout_ms, int want_keepalive)
1.1 deraadt 429: {
1.313 dtucker 430: int on = 1, saved_timeout_ms = *timeout_ms;
1.290 djm 431: int oerrno, sock = -1, attempt;
1.90 markus 432: char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1.241 djm 433: struct addrinfo *ai;
1.38 markus 434:
1.341 djm 435: debug3_f("entering");
1.268 djm 436: memset(ntop, 0, sizeof(ntop));
437: memset(strport, 0, sizeof(strport));
1.38 markus 438:
1.181 markus 439: for (attempt = 0; attempt < connection_attempts; attempt++) {
1.200 markus 440: if (attempt > 0) {
441: /* Sleep a moment before retrying. */
442: sleep(1);
1.38 markus 443: debug("Trying again...");
1.200 markus 444: }
1.181 markus 445: /*
446: * Loop through addresses for this host, and try each one in
447: * sequence until the connection succeeds.
448: */
1.49 markus 449: for (ai = aitop; ai; ai = ai->ai_next) {
1.241 djm 450: if (ai->ai_family != AF_INET &&
1.290 djm 451: ai->ai_family != AF_INET6) {
452: errno = EAFNOSUPPORT;
1.49 markus 453: continue;
1.290 djm 454: }
1.49 markus 455: if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
456: ntop, sizeof(ntop), strport, sizeof(strport),
457: NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1.290 djm 458: oerrno = errno;
1.341 djm 459: error_f("getnameinfo failed");
1.290 djm 460: errno = oerrno;
1.49 markus 461: continue;
462: }
1.364 djm 463: if (options.address_family != AF_UNSPEC &&
464: ai->ai_family != options.address_family) {
465: debug2_f("skipping address [%s]:%s: "
466: "wrong address family", ntop, strport);
1.365 djm 467: errno = EAFNOSUPPORT;
1.364 djm 468: continue;
469: }
470:
1.49 markus 471: debug("Connecting to %.200s [%.100s] port %s.",
472: host, ntop, strport);
473:
474: /* Create a socket for connecting. */
1.302 dtucker 475: sock = ssh_create_socket(ai);
1.292 stsp 476: if (sock < 0) {
1.110 markus 477: /* Any error is already output */
1.290 djm 478: errno = 0;
1.49 markus 479: continue;
1.292 stsp 480: }
1.49 markus 481:
1.313 dtucker 482: *timeout_ms = saved_timeout_ms;
1.141 djm 483: if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
1.202 djm 484: timeout_ms) >= 0) {
1.49 markus 485: /* Successful connection. */
1.102 markus 486: memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
1.38 markus 487: break;
1.49 markus 488: } else {
1.290 djm 489: oerrno = errno;
1.131 itojun 490: debug("connect to address %s port %s: %s",
491: ntop, strport, strerror(errno));
1.38 markus 492: close(sock);
1.181 markus 493: sock = -1;
1.290 djm 494: errno = oerrno;
1.38 markus 495: }
496: }
1.181 markus 497: if (sock != -1)
1.49 markus 498: break; /* Successful connection. */
1.38 markus 499: }
1.49 markus 500:
1.38 markus 501: /* Return failure if we didn't get a successful connection. */
1.181 markus 502: if (sock == -1) {
1.159 markus 503: error("ssh: connect to host %s port %s: %s",
1.290 djm 504: host, strport, errno == 0 ? "failure" : strerror(errno));
505: return -1;
1.130 itojun 506: }
1.38 markus 507:
508: debug("Connection established.");
1.90 markus 509:
1.155 markus 510: /* Set SO_KEEPALIVE if requested. */
1.202 djm 511: if (want_keepalive &&
1.90 markus 512: setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
1.317 deraadt 513: sizeof(on)) == -1)
1.90 markus 514: error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1.38 markus 515:
516: /* Set the connection. */
1.286 djm 517: if (ssh_packet_set_connection(ssh, sock, sock) == NULL)
518: return -1; /* ssh_packet_set_connection logs error */
1.1 deraadt 519:
1.319 djm 520: return 0;
1.59 markus 521: }
522:
1.241 djm 523: int
1.318 djm 524: ssh_connect(struct ssh *ssh, const char *host, const char *host_arg,
525: struct addrinfo *addrs, struct sockaddr_storage *hostaddr, u_short port,
1.340 kn 526: int connection_attempts, int *timeout_ms, int want_keepalive)
1.241 djm 527: {
1.314 markus 528: int in, out;
529:
1.241 djm 530: if (options.proxy_command == NULL) {
1.286 djm 531: return ssh_connect_direct(ssh, host, addrs, hostaddr, port,
1.340 kn 532: connection_attempts, timeout_ms, want_keepalive);
1.241 djm 533: } else if (strcmp(options.proxy_command, "-") == 0) {
1.317 deraadt 534: if ((in = dup(STDIN_FILENO)) == -1 ||
535: (out = dup(STDOUT_FILENO)) == -1) {
1.314 markus 536: if (in >= 0)
537: close(in);
1.341 djm 538: error_f("dup() in/out failed");
1.314 markus 539: return -1; /* ssh_packet_set_connection logs error */
540: }
541: if ((ssh_packet_set_connection(ssh, in, out)) == NULL)
1.286 djm 542: return -1; /* ssh_packet_set_connection logs error */
543: return 0;
1.241 djm 544: } else if (options.proxy_use_fdpass) {
1.318 djm 545: return ssh_proxy_fdpass_connect(ssh, host, host_arg, port,
1.241 djm 546: options.proxy_command);
547: }
1.318 djm 548: return ssh_proxy_connect(ssh, host, host_arg, port,
549: options.proxy_command);
1.241 djm 550: }
551:
1.96 markus 552: /* defaults to 'no' */
1.109 itojun 553: static int
1.312 dtucker 554: confirm(const char *prompt, const char *fingerprint)
1.1 deraadt 555: {
1.119 markus 556: const char *msg, *again = "Please type 'yes' or 'no': ";
1.312 dtucker 557: const char *again_fp = "Please type 'yes', 'no' or the fingerprint: ";
1.326 dtucker 558: char *p, *cp;
1.119 markus 559: int ret = -1;
1.96 markus 560:
561: if (options.batch_mode)
562: return 0;
1.312 dtucker 563: for (msg = prompt;;msg = fingerprint ? again_fp : again) {
1.326 dtucker 564: cp = p = read_passphrase(msg, RP_ECHO);
1.289 djm 565: if (p == NULL)
566: return 0;
1.326 dtucker 567: p += strspn(p, " \t"); /* skip leading whitespace */
568: p[strcspn(p, " \t\n")] = '\0'; /* remove trailing whitespace */
1.289 djm 569: if (p[0] == '\0' || strcasecmp(p, "no") == 0)
1.119 markus 570: ret = 0;
1.312 dtucker 571: else if (strcasecmp(p, "yes") == 0 || (fingerprint != NULL &&
1.332 djm 572: strcmp(p, fingerprint) == 0))
1.119 markus 573: ret = 1;
1.326 dtucker 574: free(cp);
1.119 markus 575: if (ret != -1)
576: return ret;
1.1 deraadt 577: }
578: }
579:
1.219 djm 580: static int
1.229 djm 581: sockaddr_is_local(struct sockaddr *hostaddr)
582: {
583: switch (hostaddr->sa_family) {
584: case AF_INET:
585: return (ntohl(((struct sockaddr_in *)hostaddr)->
586: sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
587: case AF_INET6:
588: return IN6_IS_ADDR_LOOPBACK(
589: &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
590: default:
591: return 0;
592: }
593: }
594:
595: /*
596: * Prepare the hostname and ip address strings that are used to lookup
597: * host keys in known_hosts files. These may have a port number appended.
598: */
599: void
600: get_hostfile_hostname_ipaddr(char *hostname, struct sockaddr *hostaddr,
601: u_short port, char **hostfile_hostname, char **hostfile_ipaddr)
602: {
603: char ntop[NI_MAXHOST];
604:
605: /*
606: * We don't have the remote ip-address for connections
607: * using a proxy command
608: */
609: if (hostfile_ipaddr != NULL) {
610: if (options.proxy_command == NULL) {
611: if (getnameinfo(hostaddr, hostaddr->sa_len,
612: ntop, sizeof(ntop), NULL, 0, NI_NUMERICHOST) != 0)
1.367 jsg 613: fatal_f("getnameinfo failed");
1.229 djm 614: *hostfile_ipaddr = put_host_port(ntop, port);
615: } else {
616: *hostfile_ipaddr = xstrdup("<no hostip for proxy "
617: "command>");
618: }
619: }
620:
621: /*
622: * Allow the user to record the key under a different name or
623: * differentiate a non-standard port. This is useful for ssh
624: * tunneling over forwarded connections or if you run multiple
625: * sshd's on different ports on the same machine.
626: */
627: if (hostfile_hostname != NULL) {
628: if (options.host_key_alias != NULL) {
629: *hostfile_hostname = xstrdup(options.host_key_alias);
630: debug("using hostkeyalias: %s", *hostfile_hostname);
631: } else {
632: *hostfile_hostname = put_host_port(hostname, port);
633: }
634: }
635: }
636:
1.338 djm 637: /* returns non-zero if path appears in hostfiles, or 0 if not. */
638: static int
639: path_in_hostfiles(const char *path, char **hostfiles, u_int num_hostfiles)
640: {
641: u_int i;
642:
643: for (i = 0; i < num_hostfiles; i++) {
644: if (strcmp(path, hostfiles[i]) == 0)
645: return 1;
646: }
647: return 0;
648: }
649:
1.342 djm 650: struct find_by_key_ctx {
651: const char *host, *ip;
652: const struct sshkey *key;
653: char **names;
654: u_int nnames;
655: };
656:
657: /* Try to replace home directory prefix (per $HOME) with a ~/ sequence */
658: static char *
659: try_tilde_unexpand(const char *path)
660: {
661: char *home, *ret = NULL;
662: size_t l;
663:
664: if (*path != '/')
665: return xstrdup(path);
666: if ((home = getenv("HOME")) == NULL || (l = strlen(home)) == 0)
667: return xstrdup(path);
668: if (strncmp(path, home, l) != 0)
669: return xstrdup(path);
670: /*
671: * ensure we have matched on a path boundary: either the $HOME that
672: * we just compared ends with a '/' or the next character of the path
673: * must be a '/'.
674: */
675: if (home[l - 1] != '/' && path[l] != '/')
676: return xstrdup(path);
677: if (path[l] == '/')
678: l++;
679: xasprintf(&ret, "~/%s", path + l);
680: return ret;
681: }
682:
1.368 ! djm 683: /*
! 684: * Returns non-zero if the key is accepted by HostkeyAlgorithms.
! 685: * Made slightly less trivial by the multiple RSA signature algorithm names.
! 686: */
! 687: int
! 688: hostkey_accepted_by_hostkeyalgs(const struct sshkey *key)
! 689: {
! 690: const char *ktype = sshkey_ssh_name(key);
! 691: const char *hostkeyalgs = options.hostkeyalgorithms;
! 692:
! 693: if (key->type == KEY_UNSPEC)
! 694: return 0;
! 695: if (key->type == KEY_RSA &&
! 696: (match_pattern_list("rsa-sha2-256", hostkeyalgs, 0) == 1 ||
! 697: match_pattern_list("rsa-sha2-512", hostkeyalgs, 0) == 1))
! 698: return 1;
! 699: if (key->type == KEY_RSA_CERT &&
! 700: (match_pattern_list("rsa-sha2-512-cert-v01@openssh.com", hostkeyalgs, 0) == 1 ||
! 701: match_pattern_list("rsa-sha2-256-cert-v01@openssh.com", hostkeyalgs, 0) == 1))
! 702: return 1;
! 703: return match_pattern_list(ktype, hostkeyalgs, 0) == 1;
! 704: }
! 705:
1.342 djm 706: static int
707: hostkeys_find_by_key_cb(struct hostkey_foreach_line *l, void *_ctx)
708: {
709: struct find_by_key_ctx *ctx = (struct find_by_key_ctx *)_ctx;
710: char *path;
711:
712: /* we are looking for keys with names that *do not* match */
713: if ((l->match & HKF_MATCH_HOST) != 0)
714: return 0;
715: /* not interested in marker lines */
716: if (l->marker != MRK_NONE)
717: return 0;
718: /* we are only interested in exact key matches */
719: if (l->key == NULL || !sshkey_equal(ctx->key, l->key))
720: return 0;
721: path = try_tilde_unexpand(l->path);
722: debug_f("found matching key in %s:%lu", path, l->linenum);
723: ctx->names = xrecallocarray(ctx->names,
724: ctx->nnames, ctx->nnames + 1, sizeof(*ctx->names));
725: xasprintf(&ctx->names[ctx->nnames], "%s:%lu: %s", path, l->linenum,
726: strncmp(l->hosts, HASH_MAGIC, strlen(HASH_MAGIC)) == 0 ?
727: "[hashed name]" : l->hosts);
728: ctx->nnames++;
729: free(path);
730: return 0;
731: }
732:
733: static int
734: hostkeys_find_by_key_hostfile(const char *file, const char *which,
735: struct find_by_key_ctx *ctx)
736: {
737: int r;
738:
739: debug3_f("trying %s hostfile \"%s\"", which, file);
740: if ((r = hostkeys_foreach(file, hostkeys_find_by_key_cb, ctx,
1.346 djm 741: ctx->host, ctx->ip, HKF_WANT_PARSE_KEY, 0)) != 0) {
1.342 djm 742: if (r == SSH_ERR_SYSTEM_ERROR && errno == ENOENT) {
743: debug_f("hostkeys file %s does not exist", file);
744: return 0;
745: }
746: error_fr(r, "hostkeys_foreach failed for %s", file);
747: return r;
748: }
749: return 0;
750: }
751:
752: /*
753: * Find 'key' in known hosts file(s) that do not match host/ip.
754: * Used to display also-known-as information for previously-unseen hostkeys.
755: */
756: static void
757: hostkeys_find_by_key(const char *host, const char *ip, const struct sshkey *key,
758: char **user_hostfiles, u_int num_user_hostfiles,
759: char **system_hostfiles, u_int num_system_hostfiles,
760: char ***names, u_int *nnames)
761: {
1.343 dtucker 762: struct find_by_key_ctx ctx = {0, 0, 0, 0, 0};
1.342 djm 763: u_int i;
764:
765: *names = NULL;
766: *nnames = 0;
767:
768: if (key == NULL || sshkey_is_cert(key))
769: return;
770:
771: ctx.host = host;
772: ctx.ip = ip;
773: ctx.key = key;
774:
775: for (i = 0; i < num_user_hostfiles; i++) {
776: if (hostkeys_find_by_key_hostfile(user_hostfiles[i],
777: "user", &ctx) != 0)
778: goto fail;
779: }
780: for (i = 0; i < num_system_hostfiles; i++) {
781: if (hostkeys_find_by_key_hostfile(system_hostfiles[i],
782: "system", &ctx) != 0)
783: goto fail;
784: }
785: /* success */
786: *names = ctx.names;
787: *nnames = ctx.nnames;
788: ctx.names = NULL;
789: ctx.nnames = 0;
790: return;
791: fail:
792: for (i = 0; i < ctx.nnames; i++)
793: free(ctx.names[i]);
794: free(ctx.names);
795: }
796:
797: #define MAX_OTHER_NAMES 8 /* Maximum number of names to list */
798: static char *
799: other_hostkeys_message(const char *host, const char *ip,
800: const struct sshkey *key,
801: char **user_hostfiles, u_int num_user_hostfiles,
802: char **system_hostfiles, u_int num_system_hostfiles)
803: {
804: char *ret = NULL, **othernames = NULL;
805: u_int i, n, num_othernames = 0;
806:
807: hostkeys_find_by_key(host, ip, key,
808: user_hostfiles, num_user_hostfiles,
809: system_hostfiles, num_system_hostfiles,
810: &othernames, &num_othernames);
811: if (num_othernames == 0)
1.357 dtucker 812: return xstrdup("This key is not known by any other names.");
1.342 djm 813:
814: xasprintf(&ret, "This host key is known by the following other "
815: "names/addresses:");
816:
817: n = num_othernames;
818: if (n > MAX_OTHER_NAMES)
819: n = MAX_OTHER_NAMES;
820: for (i = 0; i < n; i++) {
821: xextendf(&ret, "\n", " %s", othernames[i]);
822: }
823: if (n < num_othernames) {
1.351 sthen 824: xextendf(&ret, "\n", " (%d additional names omitted)",
1.342 djm 825: num_othernames - n);
826: }
827: for (i = 0; i < num_othernames; i++)
828: free(othernames[i]);
829: free(othernames);
830: return ret;
831: }
832:
1.349 djm 833: void
834: load_hostkeys_command(struct hostkeys *hostkeys, const char *command_template,
835: const char *invocation, const struct ssh_conn_info *cinfo,
836: const struct sshkey *host_key, const char *hostfile_hostname)
837: {
838: int r, i, ac = 0;
839: char *key_fp = NULL, *keytext = NULL, *tmp;
840: char *command = NULL, *tag = NULL, **av = NULL;
841: FILE *f = NULL;
842: pid_t pid;
843: void (*osigchld)(int);
844:
845: xasprintf(&tag, "KnownHostsCommand-%s", invocation);
846:
847: if (host_key != NULL) {
848: if ((key_fp = sshkey_fingerprint(host_key,
849: options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
850: fatal_f("sshkey_fingerprint failed");
851: if ((r = sshkey_to_base64(host_key, &keytext)) != 0)
852: fatal_fr(r, "sshkey_to_base64 failed");
853: }
854: /*
855: * NB. all returns later this function should go via "out" to
856: * ensure the original SIGCHLD handler is restored properly.
857: */
858: osigchld = ssh_signal(SIGCHLD, SIG_DFL);
859:
860: /* Turn the command into an argument vector */
1.353 djm 861: if (argv_split(command_template, &ac, &av, 0) != 0) {
1.349 djm 862: error("%s \"%s\" contains invalid quotes", tag,
1.352 djm 863: command_template);
1.349 djm 864: goto out;
865: }
866: if (ac == 0) {
867: error("%s \"%s\" yielded no arguments", tag,
868: command_template);
869: goto out;
870: }
871: for (i = 1; i < ac; i++) {
872: tmp = percent_dollar_expand(av[i],
873: DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
874: "H", hostfile_hostname,
875: "I", invocation,
876: "t", host_key == NULL ? "NONE" : sshkey_ssh_name(host_key),
877: "f", key_fp == NULL ? "NONE" : key_fp,
878: "K", keytext == NULL ? "NONE" : keytext,
879: (char *)NULL);
880: if (tmp == NULL)
881: fatal_f("percent_expand failed");
882: free(av[i]);
883: av[i] = tmp;
884: }
885: /* Prepare a printable command for logs, etc. */
886: command = argv_assemble(ac, av);
887:
888: if ((pid = subprocess(tag, command, ac, av, &f,
889: SSH_SUBPROCESS_STDOUT_CAPTURE|SSH_SUBPROCESS_UNSAFE_PATH|
890: SSH_SUBPROCESS_PRESERVE_ENV, NULL, NULL, NULL)) == 0)
891: goto out;
892:
893: load_hostkeys_file(hostkeys, hostfile_hostname, tag, f, 1);
894:
895: if (exited_cleanly(pid, tag, command, 0) != 0)
896: fatal("KnownHostsCommand failed");
897:
898: out:
899: if (f != NULL)
900: fclose(f);
901: ssh_signal(SIGCHLD, osigchld);
902: for (i = 0; i < ac; i++)
903: free(av[i]);
904: free(av);
905: free(tag);
906: free(command);
907: free(key_fp);
908: free(keytext);
909: }
910:
1.39 deraadt 911: /*
1.108 markus 912: * check whether the supplied host key is valid, return -1 if the key
1.234 djm 913: * is not valid. user_hostfile[0] will not be updated if 'readonly' is true.
1.39 deraadt 914: */
1.197 dtucker 915: #define RDRW 0
916: #define RDONLY 1
917: #define ROQUIET 2
1.109 itojun 918: static int
1.348 djm 919: check_host_key(char *hostname, const struct ssh_conn_info *cinfo,
920: struct sockaddr *hostaddr, u_short port,
921: struct sshkey *host_key, int readonly, int clobber_port,
1.234 djm 922: char **user_hostfiles, u_int num_user_hostfiles,
1.349 djm 923: char **system_hostfiles, u_int num_system_hostfiles,
924: const char *hostfile_command)
1.1 deraadt 925: {
1.338 djm 926: HostStatus host_status = -1, ip_status = -1;
1.279 markus 927: struct sshkey *raw_key = NULL;
1.189 dtucker 928: char *ip = NULL, *host = NULL;
1.204 grunk 929: char hostline[1000], *hostp, *fp, *ra;
1.119 markus 930: char msg[1024];
1.359 djm 931: const char *type, *fail_reason = NULL;
1.338 djm 932: const struct hostkey_entry *host_found = NULL, *ip_found = NULL;
1.312 dtucker 933: int len, cancelled_forwarding = 0, confirmed;
1.337 djm 934: int local = sockaddr_is_local(hostaddr);
1.280 markus 935: int r, want_cert = sshkey_is_cert(host_key), host_ip_differ = 0;
1.257 djm 936: int hostkey_trusted = 0; /* Known or explicitly accepted by user */
1.229 djm 937: struct hostkeys *host_hostkeys, *ip_hostkeys;
1.234 djm 938: u_int i;
1.49 markus 939:
940: /*
941: * Force accepting of the host key for loopback/localhost. The
942: * problem is that if the home directory is NFS-mounted to multiple
943: * machines, localhost will refer to a different machine in each of
944: * them, and the user will get bogus HOST_CHANGED warnings. This
945: * essentially disables host authentication for localhost; however,
946: * this is probably not a real problem.
947: */
1.111 markus 948: if (options.no_host_authentication_for_localhost == 1 && local &&
949: options.host_key_alias == NULL) {
1.88 markus 950: debug("Forcing accepting of host key for "
951: "loopback/localhost.");
1.338 djm 952: options.update_hostkeys = 0;
1.108 markus 953: return 0;
1.49 markus 954: }
1.42 markus 955:
956: /*
1.360 djm 957: * Don't ever try to write an invalid name to a known hosts file.
958: * Note: do this before get_hostfile_hostname_ipaddr() to catch
959: * '[' or ']' in the name before they are added.
960: */
961: if (strcspn(hostname, "@?*#[]|'\'\"\\") != strlen(hostname)) {
962: debug_f("invalid hostname \"%s\"; will not record: %s",
963: hostname, fail_reason);
964: readonly = RDONLY;
965: }
966:
967: /*
1.229 djm 968: * Prepare the hostname and address strings used for hostkey lookup.
969: * In some cases, these will have a port number appended.
1.42 markus 970: */
1.348 djm 971: get_hostfile_hostname_ipaddr(hostname, hostaddr,
972: clobber_port ? 0 : port, &host, &ip);
1.206 grunk 973:
974: /*
1.88 markus 975: * Turn off check_host_ip if the connection is to localhost, via proxy
976: * command or if we don't have a hostname to compare with
977: */
1.189 dtucker 978: if (options.check_host_ip && (local ||
979: strcmp(hostname, ip) == 0 || options.proxy_command != NULL))
1.88 markus 980: options.check_host_ip = 0;
1.86 markus 981:
1.229 djm 982: host_hostkeys = init_hostkeys();
1.234 djm 983: for (i = 0; i < num_user_hostfiles; i++)
1.346 djm 984: load_hostkeys(host_hostkeys, host, user_hostfiles[i], 0);
1.234 djm 985: for (i = 0; i < num_system_hostfiles; i++)
1.346 djm 986: load_hostkeys(host_hostkeys, host, system_hostfiles[i], 0);
1.349 djm 987: if (hostfile_command != NULL && !clobber_port) {
988: load_hostkeys_command(host_hostkeys, hostfile_command,
989: "HOSTNAME", cinfo, host_key, host);
990: }
1.229 djm 991:
992: ip_hostkeys = NULL;
993: if (!want_cert && options.check_host_ip) {
994: ip_hostkeys = init_hostkeys();
1.234 djm 995: for (i = 0; i < num_user_hostfiles; i++)
1.346 djm 996: load_hostkeys(ip_hostkeys, ip, user_hostfiles[i], 0);
1.234 djm 997: for (i = 0; i < num_system_hostfiles; i++)
1.346 djm 998: load_hostkeys(ip_hostkeys, ip, system_hostfiles[i], 0);
1.349 djm 999: if (hostfile_command != NULL && !clobber_port) {
1000: load_hostkeys_command(ip_hostkeys, hostfile_command,
1001: "ADDRESS", cinfo, host_key, ip);
1002: }
1.84 markus 1003: }
1.38 markus 1004:
1.219 djm 1005: retry:
1.368 ! djm 1006: if (!hostkey_accepted_by_hostkeyalgs(host_key)) {
! 1007: error("host key %s not permitted by HostkeyAlgorithms",
! 1008: sshkey_ssh_name(host_key));
! 1009: goto fail;
! 1010: }
! 1011:
1.229 djm 1012: /* Reload these as they may have changed on cert->key downgrade */
1.280 markus 1013: want_cert = sshkey_is_cert(host_key);
1014: type = sshkey_type(host_key);
1.219 djm 1015:
1.46 markus 1016: /*
1.170 djm 1017: * Check if the host key is present in the user's list of known
1.40 markus 1018: * hosts or in the systemwide list.
1019: */
1.229 djm 1020: host_status = check_key_in_hostkeys(host_hostkeys, host_key,
1021: &host_found);
1.347 djm 1022:
1.349 djm 1023: /*
1024: * If there are no hostfiles, or if the hostkey was found via
1025: * KnownHostsCommand, then don't try to touch the disk.
1026: */
1027: if (!readonly && (num_user_hostfiles == 0 ||
1028: (host_found != NULL && host_found->note != 0)))
1.347 djm 1029: readonly = RDONLY;
1.229 djm 1030:
1.40 markus 1031: /*
1032: * Also perform check for the ip address, skip the check if we are
1.219 djm 1033: * localhost, looking for a certificate, or the hostname was an ip
1034: * address to begin with.
1.40 markus 1035: */
1.229 djm 1036: if (!want_cert && ip_hostkeys != NULL) {
1037: ip_status = check_key_in_hostkeys(ip_hostkeys, host_key,
1038: &ip_found);
1.38 markus 1039: if (host_status == HOST_CHANGED &&
1.319 djm 1040: (ip_status != HOST_CHANGED ||
1.229 djm 1041: (ip_found != NULL &&
1.280 markus 1042: !sshkey_equal(ip_found->key, host_found->key))))
1.38 markus 1043: host_ip_differ = 1;
1044: } else
1045: ip_status = host_status;
1046:
1047: switch (host_status) {
1048: case HOST_OK:
1049: /* The host is known and the key matches. */
1.219 djm 1050: debug("Host '%.200s' is known and matches the %s host %s.",
1051: host, type, want_cert ? "certificate" : "key");
1.229 djm 1052: debug("Found %s in %s:%lu", want_cert ? "CA key" : "key",
1053: host_found->file, host_found->line);
1.350 djm 1054: if (want_cert) {
1055: if (sshkey_cert_check_host(host_key,
1056: options.host_key_alias == NULL ?
1057: hostname : options.host_key_alias, 0,
1058: options.ca_sign_algorithms, &fail_reason) != 0) {
1059: error("%s", fail_reason);
1060: goto fail;
1061: }
1062: /*
1063: * Do not attempt hostkey update if a certificate was
1064: * successfully matched.
1065: */
1066: if (options.update_hostkeys != 0) {
1067: options.update_hostkeys = 0;
1068: debug3_f("certificate host key in use; "
1069: "disabling UpdateHostkeys");
1070: }
1071: }
1.338 djm 1072: /* Turn off UpdateHostkeys if key was in system known_hosts */
1073: if (options.update_hostkeys != 0 &&
1074: (path_in_hostfiles(host_found->file,
1075: system_hostfiles, num_system_hostfiles) ||
1076: (ip_status == HOST_OK && ip_found != NULL &&
1077: path_in_hostfiles(ip_found->file,
1078: system_hostfiles, num_system_hostfiles)))) {
1079: options.update_hostkeys = 0;
1.341 djm 1080: debug3_f("host key found in GlobalKnownHostsFile; "
1081: "disabling UpdateHostkeys");
1.338 djm 1082: }
1.349 djm 1083: if (options.update_hostkeys != 0 && host_found->note) {
1084: options.update_hostkeys = 0;
1085: debug3_f("host key found via KnownHostsCommand; "
1086: "disabling UpdateHostkeys");
1087: }
1.88 markus 1088: if (options.check_host_ip && ip_status == HOST_NEW) {
1.219 djm 1089: if (readonly || want_cert)
1.138 itojun 1090: logit("%s host key for IP address "
1.108 markus 1091: "'%.128s' not in list of known hosts.",
1092: type, ip);
1.234 djm 1093: else if (!add_host_to_hostfile(user_hostfiles[0], ip,
1.160 djm 1094: host_key, options.hash_known_hosts))
1.138 itojun 1095: logit("Failed to add the %s host key for IP "
1.108 markus 1096: "address '%.128s' to the list of known "
1.262 dtucker 1097: "hosts (%.500s).", type, ip,
1.234 djm 1098: user_hostfiles[0]);
1.88 markus 1099: else
1.138 itojun 1100: logit("Warning: Permanently added the %s host "
1.108 markus 1101: "key for IP address '%.128s' to the list "
1102: "of known hosts.", type, ip);
1.209 grunk 1103: } else if (options.visual_host_key) {
1.259 djm 1104: fp = sshkey_fingerprint(host_key,
1.254 djm 1105: options.fingerprint_hash, SSH_FP_DEFAULT);
1.259 djm 1106: ra = sshkey_fingerprint(host_key,
1.254 djm 1107: options.fingerprint_hash, SSH_FP_RANDOMART);
1.259 djm 1108: if (fp == NULL || ra == NULL)
1.341 djm 1109: fatal_f("sshkey_fingerprint failed");
1.264 djm 1110: logit("Host key fingerprint is %s\n%s", fp, ra);
1.238 djm 1111: free(ra);
1112: free(fp);
1.38 markus 1113: }
1.257 djm 1114: hostkey_trusted = 1;
1.38 markus 1115: break;
1116: case HOST_NEW:
1.197 dtucker 1117: if (options.host_key_alias == NULL && port != 0 &&
1.348 djm 1118: port != SSH_DEFAULT_PORT && !clobber_port) {
1.197 dtucker 1119: debug("checking without port identifier");
1.348 djm 1120: if (check_host_key(hostname, cinfo, hostaddr, 0,
1121: host_key, ROQUIET, 1,
1122: user_hostfiles, num_user_hostfiles,
1.349 djm 1123: system_hostfiles, num_system_hostfiles,
1124: hostfile_command) == 0) {
1.197 dtucker 1125: debug("found matching key w/out port");
1126: break;
1127: }
1128: }
1.219 djm 1129: if (readonly || want_cert)
1.108 markus 1130: goto fail;
1.38 markus 1131: /* The host is new. */
1.285 djm 1132: if (options.strict_host_key_checking ==
1133: SSH_STRICT_HOSTKEY_YES) {
1.108 markus 1134: /*
1135: * User has requested strict host key checking. We
1136: * will not add the host key automatically. The only
1137: * alternative left is to abort.
1138: */
1139: error("No %s host key is known for %.200s and you "
1140: "have requested strict checking.", type, host);
1141: goto fail;
1.285 djm 1142: } else if (options.strict_host_key_checking ==
1143: SSH_STRICT_HOSTKEY_ASK) {
1.342 djm 1144: char *msg1 = NULL, *msg2 = NULL;
1145:
1146: xasprintf(&msg1, "The authenticity of host "
1147: "'%.200s (%s)' can't be established", host, ip);
1148:
1149: if (show_other_keys(host_hostkeys, host_key)) {
1150: xextendf(&msg1, "\n", "but keys of different "
1151: "type are already known for this host.");
1152: } else
1153: xextendf(&msg1, "", ".");
1.145 jakob 1154:
1.259 djm 1155: fp = sshkey_fingerprint(host_key,
1.254 djm 1156: options.fingerprint_hash, SSH_FP_DEFAULT);
1.259 djm 1157: ra = sshkey_fingerprint(host_key,
1.254 djm 1158: options.fingerprint_hash, SSH_FP_RANDOMART);
1.259 djm 1159: if (fp == NULL || ra == NULL)
1.341 djm 1160: fatal_f("sshkey_fingerprint failed");
1.342 djm 1161: xextendf(&msg1, "\n", "%s key fingerprint is %s.",
1162: type, fp);
1163: if (options.visual_host_key)
1164: xextendf(&msg1, "\n", "%s", ra);
1.145 jakob 1165: if (options.verify_host_key_dns) {
1.342 djm 1166: xextendf(&msg1, "\n",
1167: "%s host key fingerprint found in DNS.",
1168: matching_host_key_dns ?
1169: "Matching" : "No matching");
1.145 jakob 1170: }
1.342 djm 1171: /* msg2 informs for other names matching this key */
1172: if ((msg2 = other_hostkeys_message(host, ip, host_key,
1173: user_hostfiles, num_user_hostfiles,
1174: system_hostfiles, num_system_hostfiles)) != NULL)
1175: xextendf(&msg1, "\n", "%s", msg2);
1176:
1177: xextendf(&msg1, "\n",
1.108 markus 1178: "Are you sure you want to continue connecting "
1.342 djm 1179: "(yes/no/[fingerprint])? ");
1180:
1181: confirmed = confirm(msg1, fp);
1.238 djm 1182: free(ra);
1183: free(fp);
1.342 djm 1184: free(msg1);
1185: free(msg2);
1.312 dtucker 1186: if (!confirmed)
1.108 markus 1187: goto fail;
1.257 djm 1188: hostkey_trusted = 1; /* user explicitly confirmed */
1.38 markus 1189: }
1.161 djm 1190: /*
1.285 djm 1191: * If in "new" or "off" strict mode, add the key automatically
1192: * to the local known_hosts file.
1.161 djm 1193: */
1.88 markus 1194: if (options.check_host_ip && ip_status == HOST_NEW) {
1.229 djm 1195: snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
1.38 markus 1196: hostp = hostline;
1.161 djm 1197: if (options.hash_known_hosts) {
1198: /* Add hash of host and IP separately */
1.234 djm 1199: r = add_host_to_hostfile(user_hostfiles[0],
1200: host, host_key, options.hash_known_hosts) &&
1201: add_host_to_hostfile(user_hostfiles[0], ip,
1.161 djm 1202: host_key, options.hash_known_hosts);
1203: } else {
1204: /* Add unhashed "host,ip" */
1.234 djm 1205: r = add_host_to_hostfile(user_hostfiles[0],
1.161 djm 1206: hostline, host_key,
1207: options.hash_known_hosts);
1208: }
1209: } else {
1.234 djm 1210: r = add_host_to_hostfile(user_hostfiles[0], host,
1211: host_key, options.hash_known_hosts);
1.38 markus 1212: hostp = host;
1.161 djm 1213: }
1.38 markus 1214:
1.161 djm 1215: if (!r)
1.138 itojun 1216: logit("Failed to add the host to the list of known "
1.234 djm 1217: "hosts (%.500s).", user_hostfiles[0]);
1.38 markus 1218: else
1.138 itojun 1219: logit("Warning: Permanently added '%.200s' (%s) to the "
1.108 markus 1220: "list of known hosts.", hostp, type);
1.38 markus 1221: break;
1.220 djm 1222: case HOST_REVOKED:
1223: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1224: error("@ WARNING: REVOKED HOST KEY DETECTED! @");
1225: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1226: error("The %s host key for %s is marked as revoked.", type, host);
1227: error("This could mean that a stolen key is being used to");
1228: error("impersonate this host.");
1229:
1230: /*
1231: * If strict host key checking is in use, the user will have
1232: * to edit the key manually and we can only abort.
1233: */
1.285 djm 1234: if (options.strict_host_key_checking !=
1235: SSH_STRICT_HOSTKEY_OFF) {
1.220 djm 1236: error("%s host key for %.200s was revoked and you have "
1237: "requested strict checking.", type, host);
1238: goto fail;
1239: }
1240: goto continue_unsafe;
1241:
1.38 markus 1242: case HOST_CHANGED:
1.219 djm 1243: if (want_cert) {
1244: /*
1245: * This is only a debug() since it is valid to have
1246: * CAs with wildcard DNS matches that don't match
1247: * all hosts that one might visit.
1248: */
1249: debug("Host certificate authority does not "
1.229 djm 1250: "match %s in %s:%lu", CA_MARKER,
1251: host_found->file, host_found->line);
1.219 djm 1252: goto fail;
1253: }
1.197 dtucker 1254: if (readonly == ROQUIET)
1255: goto fail;
1.38 markus 1256: if (options.check_host_ip && host_ip_differ) {
1.158 avsm 1257: char *key_msg;
1.38 markus 1258: if (ip_status == HOST_NEW)
1.158 avsm 1259: key_msg = "is unknown";
1.38 markus 1260: else if (ip_status == HOST_OK)
1.158 avsm 1261: key_msg = "is unchanged";
1.38 markus 1262: else
1.158 avsm 1263: key_msg = "has a different value";
1.38 markus 1264: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1265: error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
1266: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1.72 markus 1267: error("The %s host key for %s has changed,", type, host);
1.208 ian 1268: error("and the key for the corresponding IP address %s", ip);
1.158 avsm 1269: error("%s. This could either mean that", key_msg);
1.38 markus 1270: error("DNS SPOOFING is happening or the IP address for the host");
1.85 markus 1271: error("and its host key have changed at the same time.");
1.88 markus 1272: if (ip_status != HOST_NEW)
1.229 djm 1273: error("Offending key for IP in %s:%lu",
1274: ip_found->file, ip_found->line);
1.38 markus 1275: }
1276: /* The host key has changed. */
1.150 jakob 1277: warn_changed_key(host_key);
1.361 djm 1278: if (num_user_hostfiles > 0 || num_system_hostfiles > 0) {
1279: error("Add correct host key in %.100s to get rid "
1280: "of this message.", num_user_hostfiles > 0 ?
1281: user_hostfiles[0] : system_hostfiles[0]);
1282: }
1.280 markus 1283: error("Offending %s key in %s:%lu",
1284: sshkey_type(host_found->key),
1.229 djm 1285: host_found->file, host_found->line);
1.38 markus 1286:
1.40 markus 1287: /*
1288: * If strict host key checking is in use, the user will have
1289: * to edit the key manually and we can only abort.
1290: */
1.285 djm 1291: if (options.strict_host_key_checking !=
1292: SSH_STRICT_HOSTKEY_OFF) {
1.344 djm 1293: error("Host key for %.200s has changed and you have "
1294: "requested strict checking.", host);
1.108 markus 1295: goto fail;
1296: }
1.38 markus 1297:
1.220 djm 1298: continue_unsafe:
1.40 markus 1299: /*
1300: * If strict host key checking has not been requested, allow
1.144 djm 1301: * the connection but without MITM-able authentication or
1.194 stevesk 1302: * forwarding.
1.40 markus 1303: */
1.38 markus 1304: if (options.password_authentication) {
1.108 markus 1305: error("Password authentication is disabled to avoid "
1306: "man-in-the-middle attacks.");
1.38 markus 1307: options.password_authentication = 0;
1.210 dtucker 1308: cancelled_forwarding = 1;
1.144 djm 1309: }
1310: if (options.kbd_interactive_authentication) {
1311: error("Keyboard-interactive authentication is disabled"
1312: " to avoid man-in-the-middle attacks.");
1313: options.kbd_interactive_authentication = 0;
1.210 dtucker 1314: cancelled_forwarding = 1;
1.38 markus 1315: }
1316: if (options.forward_agent) {
1.108 markus 1317: error("Agent forwarding is disabled to avoid "
1318: "man-in-the-middle attacks.");
1.38 markus 1319: options.forward_agent = 0;
1.210 dtucker 1320: cancelled_forwarding = 1;
1.83 markus 1321: }
1322: if (options.forward_x11) {
1.108 markus 1323: error("X11 forwarding is disabled to avoid "
1324: "man-in-the-middle attacks.");
1.83 markus 1325: options.forward_x11 = 0;
1.210 dtucker 1326: cancelled_forwarding = 1;
1.83 markus 1327: }
1.108 markus 1328: if (options.num_local_forwards > 0 ||
1329: options.num_remote_forwards > 0) {
1330: error("Port forwarding is disabled to avoid "
1331: "man-in-the-middle attacks.");
1332: options.num_local_forwards =
1.118 deraadt 1333: options.num_remote_forwards = 0;
1.210 dtucker 1334: cancelled_forwarding = 1;
1.194 stevesk 1335: }
1336: if (options.tun_open != SSH_TUNMODE_NO) {
1337: error("Tunnel forwarding is disabled to avoid "
1338: "man-in-the-middle attacks.");
1339: options.tun_open = SSH_TUNMODE_NO;
1.210 dtucker 1340: cancelled_forwarding = 1;
1.339 djm 1341: }
1342: if (options.update_hostkeys != 0) {
1343: error("UpdateHostkeys is disabled because the host "
1344: "key is not trusted.");
1345: options.update_hostkeys = 0;
1.38 markus 1346: }
1.210 dtucker 1347: if (options.exit_on_forward_failure && cancelled_forwarding)
1348: fatal("Error: forwarding disabled due to host key "
1349: "check failure");
1.358 djm 1350:
1.40 markus 1351: /*
1352: * XXX Should permit the user to change to use the new id.
1353: * This could be done by converting the host key to an
1354: * identifying sentence, tell that the host identifies itself
1.354 dtucker 1355: * by that sentence, and ask the user if they wish to
1.40 markus 1356: * accept the authentication.
1357: */
1.38 markus 1358: break;
1.132 markus 1359: case HOST_FOUND:
1360: fatal("internal error");
1361: break;
1.88 markus 1362: }
1363:
1364: if (options.check_host_ip && host_status != HOST_CHANGED &&
1365: ip_status == HOST_CHANGED) {
1.119 markus 1366: snprintf(msg, sizeof(msg),
1367: "Warning: the %s host key for '%.200s' "
1368: "differs from the key for the IP address '%.128s'"
1.229 djm 1369: "\nOffending key for IP in %s:%lu",
1370: type, host, ip, ip_found->file, ip_found->line);
1.119 markus 1371: if (host_status == HOST_OK) {
1372: len = strlen(msg);
1373: snprintf(msg + len, sizeof(msg) - len,
1.229 djm 1374: "\nMatching host key in %s:%lu",
1375: host_found->file, host_found->line);
1.119 markus 1376: }
1.285 djm 1377: if (options.strict_host_key_checking ==
1378: SSH_STRICT_HOSTKEY_ASK) {
1.119 markus 1379: strlcat(msg, "\nAre you sure you want "
1380: "to continue connecting (yes/no)? ", sizeof(msg));
1.312 dtucker 1381: if (!confirm(msg, NULL))
1.108 markus 1382: goto fail;
1.285 djm 1383: } else if (options.strict_host_key_checking !=
1384: SSH_STRICT_HOSTKEY_OFF) {
1385: logit("%s", msg);
1386: error("Exiting, you have requested strict checking.");
1387: goto fail;
1.119 markus 1388: } else {
1.143 djm 1389: logit("%s", msg);
1.88 markus 1390: }
1.257 djm 1391: }
1392:
1393: if (!hostkey_trusted && options.update_hostkeys) {
1.341 djm 1394: debug_f("hostkey not known or explicitly trusted: "
1395: "disabling UpdateHostkeys");
1.257 djm 1396: options.update_hostkeys = 0;
1.38 markus 1397: }
1.82 provos 1398:
1.238 djm 1399: free(ip);
1400: free(host);
1.229 djm 1401: if (host_hostkeys != NULL)
1402: free_hostkeys(host_hostkeys);
1403: if (ip_hostkeys != NULL)
1404: free_hostkeys(ip_hostkeys);
1.108 markus 1405: return 0;
1406:
1407: fail:
1.337 djm 1408: if (want_cert && host_status != HOST_REVOKED) {
1.219 djm 1409: /*
1410: * No matching certificate. Downgrade cert to raw key and
1411: * search normally.
1412: */
1413: debug("No matching CA found. Retry with plain key");
1.280 markus 1414: if ((r = sshkey_from_private(host_key, &raw_key)) != 0)
1.341 djm 1415: fatal_fr(r, "decode key");
1.280 markus 1416: if ((r = sshkey_drop_cert(raw_key)) != 0)
1.341 djm 1417: fatal_r(r, "Couldn't drop certificate");
1.219 djm 1418: host_key = raw_key;
1419: goto retry;
1420: }
1.293 dtucker 1421: sshkey_free(raw_key);
1.238 djm 1422: free(ip);
1423: free(host);
1.229 djm 1424: if (host_hostkeys != NULL)
1425: free_hostkeys(host_hostkeys);
1426: if (ip_hostkeys != NULL)
1427: free_hostkeys(ip_hostkeys);
1.108 markus 1428: return -1;
1429: }
1430:
1.337 djm 1431: /* returns 0 if key verifies or -1 if key does NOT verify */
1.108 markus 1432: int
1.348 djm 1433: verify_host_key(char *host, struct sockaddr *hostaddr, struct sshkey *host_key,
1434: const struct ssh_conn_info *cinfo)
1.108 markus 1435: {
1.267 djm 1436: u_int i;
1.337 djm 1437: int r = -1, flags = 0;
1.267 djm 1438: char valid[64], *fp = NULL, *cafp = NULL;
1.252 djm 1439: struct sshkey *plain = NULL;
1.229 djm 1440:
1.252 djm 1441: if ((fp = sshkey_fingerprint(host_key,
1.254 djm 1442: options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) {
1.341 djm 1443: error_fr(r, "fingerprint host key");
1.252 djm 1444: r = -1;
1445: goto out;
1446: }
1447:
1.267 djm 1448: if (sshkey_is_cert(host_key)) {
1449: if ((cafp = sshkey_fingerprint(host_key->cert->signature_key,
1450: options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) {
1.341 djm 1451: error_fr(r, "fingerprint CA key");
1.267 djm 1452: r = -1;
1453: goto out;
1454: }
1455: sshkey_format_cert_validity(host_key->cert,
1456: valid, sizeof(valid));
1457: debug("Server host certificate: %s %s, serial %llu "
1458: "ID \"%s\" CA %s %s valid %s",
1459: sshkey_ssh_name(host_key), fp,
1.269 djm 1460: (unsigned long long)host_key->cert->serial,
1461: host_key->cert->key_id,
1.267 djm 1462: sshkey_ssh_name(host_key->cert->signature_key), cafp,
1463: valid);
1464: for (i = 0; i < host_key->cert->nprincipals; i++) {
1465: debug2("Server host certificate hostname: %s",
1466: host_key->cert->principals[i]);
1467: }
1468: } else {
1.276 djm 1469: debug("Server host key: %s %s", sshkey_ssh_name(host_key), fp);
1.267 djm 1470: }
1.252 djm 1471:
1472: if (sshkey_equal(previous_host_key, host_key)) {
1.341 djm 1473: debug2_f("server host key %s %s matches cached key",
1474: sshkey_type(host_key), fp);
1.252 djm 1475: r = 0;
1476: goto out;
1477: }
1478:
1479: /* Check in RevokedHostKeys file if specified */
1480: if (options.revoked_host_keys != NULL) {
1481: r = sshkey_check_revoked(host_key, options.revoked_host_keys);
1482: switch (r) {
1483: case 0:
1484: break; /* not revoked */
1485: case SSH_ERR_KEY_REVOKED:
1486: error("Host key %s %s revoked by file %s",
1487: sshkey_type(host_key), fp,
1488: options.revoked_host_keys);
1489: r = -1;
1490: goto out;
1491: default:
1.341 djm 1492: error_r(r, "Error checking host key %s %s in "
1493: "revoked keys file %s", sshkey_type(host_key),
1494: fp, options.revoked_host_keys);
1.252 djm 1495: r = -1;
1496: goto out;
1497: }
1.250 djm 1498: }
1499:
1.247 djm 1500: if (options.verify_host_key_dns) {
1501: /*
1502: * XXX certs are not yet supported for DNS, so downgrade
1503: * them and try the plain key.
1504: */
1.252 djm 1505: if ((r = sshkey_from_private(host_key, &plain)) != 0)
1506: goto out;
1507: if (sshkey_is_cert(plain))
1508: sshkey_drop_cert(plain);
1.247 djm 1509: if (verify_host_key_dns(host, hostaddr, plain, &flags) == 0) {
1510: if (flags & DNS_VERIFY_FOUND) {
1511: if (options.verify_host_key_dns == 1 &&
1512: flags & DNS_VERIFY_MATCH &&
1513: flags & DNS_VERIFY_SECURE) {
1.250 djm 1514: r = 0;
1.252 djm 1515: goto out;
1.247 djm 1516: }
1517: if (flags & DNS_VERIFY_MATCH) {
1518: matching_host_key_dns = 1;
1519: } else {
1.287 djm 1520: warn_changed_key(plain);
1521: error("Update the SSHFP RR in DNS "
1522: "with the new host key to get rid "
1523: "of this message.");
1.247 djm 1524: }
1.153 jakob 1525: }
1.140 jakob 1526: }
1527: }
1.348 djm 1528: r = check_host_key(host, cinfo, hostaddr, options.port, host_key,
1529: RDRW, 0, options.user_hostfiles, options.num_user_hostfiles,
1.349 djm 1530: options.system_hostfiles, options.num_system_hostfiles,
1531: options.known_hosts_command);
1.250 djm 1532:
1.252 djm 1533: out:
1534: sshkey_free(plain);
1535: free(fp);
1.267 djm 1536: free(cafp);
1.337 djm 1537: if (r == 0 && host_key != NULL) {
1538: sshkey_free(previous_host_key);
1539: r = sshkey_from_private(host_key, &previous_host_key);
1.250 djm 1540: }
1541:
1542: return r;
1.51 markus 1543: }
1.70 markus 1544:
1.51 markus 1545: /*
1546: * Starts a dialog with the server, and authenticates the current user on the
1547: * server. This does not need any extra privileges. The basic connection
1548: * to the server must already have been established before this is called.
1549: * If login fails, this function prints an error and never returns.
1550: * This function does not require super-user privileges.
1551: */
1552: void
1.309 djm 1553: ssh_login(struct ssh *ssh, Sensitive *sensitive, const char *orighost,
1.348 djm 1554: struct sockaddr *hostaddr, u_short port, struct passwd *pw, int timeout_ms,
1555: const struct ssh_conn_info *cinfo)
1.51 markus 1556: {
1.241 djm 1557: char *host;
1.70 markus 1558: char *server_user, *local_user;
1.329 djm 1559: int r;
1.70 markus 1560:
1561: local_user = xstrdup(pw->pw_name);
1562: server_user = options.user ? options.user : local_user;
1.51 markus 1563:
1564: /* Convert the user-supplied hostname into all lowercase. */
1565: host = xstrdup(orighost);
1.241 djm 1566: lowercase(host);
1.51 markus 1567:
1568: /* Exchange protocol version identification strings with the server. */
1.329 djm 1569: if ((r = kex_exchange_identification(ssh, timeout_ms, NULL)) != 0)
1570: sshpkt_fatal(ssh, r, "banner exchange");
1.51 markus 1571:
1572: /* Put the connection into non-blocking mode. */
1.309 djm 1573: ssh_packet_set_nonblocking(ssh);
1.51 markus 1574:
1575: /* key exchange */
1576: /* authenticate user */
1.261 dtucker 1577: debug("Authenticating to %s:%d as '%s'", host, port, server_user);
1.348 djm 1578: ssh_kex2(ssh, host, hostaddr, port, cinfo);
1.309 djm 1579: ssh_userauth2(ssh, local_user, server_user, host, sensitive);
1.238 djm 1580: free(local_user);
1.315 dtucker 1581: free(host);
1.132 markus 1582: }
1583:
1584: /* print all known host keys for a given host, but skip keys of given type */
1585: static int
1.279 markus 1586: show_other_keys(struct hostkeys *hostkeys, struct sshkey *key)
1.132 markus 1587: {
1.242 djm 1588: int type[] = {
1589: KEY_RSA,
1.366 djm 1590: #ifdef WITH_DSA
1.242 djm 1591: KEY_DSA,
1.366 djm 1592: #endif
1.242 djm 1593: KEY_ECDSA,
1594: KEY_ED25519,
1.297 markus 1595: KEY_XMSS,
1.242 djm 1596: -1
1597: };
1.229 djm 1598: int i, ret = 0;
1599: char *fp, *ra;
1600: const struct hostkey_entry *found;
1.132 markus 1601:
1602: for (i = 0; type[i] != -1; i++) {
1603: if (type[i] == key->type)
1604: continue;
1.335 djm 1605: if (!lookup_key_in_hostkeys_by_type(hostkeys, type[i],
1606: -1, &found))
1.132 markus 1607: continue;
1.259 djm 1608: fp = sshkey_fingerprint(found->key,
1.254 djm 1609: options.fingerprint_hash, SSH_FP_DEFAULT);
1.259 djm 1610: ra = sshkey_fingerprint(found->key,
1.254 djm 1611: options.fingerprint_hash, SSH_FP_RANDOMART);
1.259 djm 1612: if (fp == NULL || ra == NULL)
1.341 djm 1613: fatal_f("sshkey_fingerprint fail");
1.229 djm 1614: logit("WARNING: %s key found for host %s\n"
1615: "in %s:%lu\n"
1616: "%s key fingerprint %s.",
1.300 markus 1617: sshkey_type(found->key),
1.229 djm 1618: found->host, found->file, found->line,
1.300 markus 1619: sshkey_type(found->key), fp);
1.229 djm 1620: if (options.visual_host_key)
1621: logit("%s", ra);
1.238 djm 1622: free(ra);
1623: free(fp);
1.229 djm 1624: ret = 1;
1.132 markus 1625: }
1.229 djm 1626: return ret;
1.150 jakob 1627: }
1628:
1629: static void
1.279 markus 1630: warn_changed_key(struct sshkey *host_key)
1.150 jakob 1631: {
1632: char *fp;
1633:
1.259 djm 1634: fp = sshkey_fingerprint(host_key, options.fingerprint_hash,
1.254 djm 1635: SSH_FP_DEFAULT);
1.259 djm 1636: if (fp == NULL)
1.341 djm 1637: fatal_f("sshkey_fingerprint fail");
1.150 jakob 1638:
1639: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1640: error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
1641: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1642: error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
1643: error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
1.230 markus 1644: error("It is also possible that a host key has just been changed.");
1.150 jakob 1645: error("The fingerprint for the %s key sent by the remote host is\n%s.",
1.300 markus 1646: sshkey_type(host_key), fp);
1.150 jakob 1647: error("Please contact your system administrator.");
1648:
1.238 djm 1649: free(fp);
1.171 reyk 1650: }
1651:
1652: /*
1653: * Execute a local command
1654: */
1655: int
1656: ssh_local_cmd(const char *args)
1657: {
1658: char *shell;
1659: pid_t pid;
1660: int status;
1.231 djm 1661: void (*osighand)(int);
1.171 reyk 1662:
1663: if (!options.permit_local_command ||
1664: args == NULL || !*args)
1665: return (1);
1666:
1.226 djm 1667: if ((shell = getenv("SHELL")) == NULL || *shell == '\0')
1.171 reyk 1668: shell = _PATH_BSHELL;
1669:
1.327 dtucker 1670: osighand = ssh_signal(SIGCHLD, SIG_DFL);
1.171 reyk 1671: pid = fork();
1672: if (pid == 0) {
1.327 dtucker 1673: ssh_signal(SIGPIPE, SIG_DFL);
1.171 reyk 1674: debug3("Executing %s -c \"%s\"", shell, args);
1675: execl(shell, shell, "-c", args, (char *)NULL);
1676: error("Couldn't execute %s -c \"%s\": %s",
1677: shell, args, strerror(errno));
1678: _exit(1);
1679: } else if (pid == -1)
1680: fatal("fork failed: %.100s", strerror(errno));
1681: while (waitpid(pid, &status, 0) == -1)
1682: if (errno != EINTR)
1683: fatal("Couldn't wait for child: %s", strerror(errno));
1.327 dtucker 1684: ssh_signal(SIGCHLD, osighand);
1.171 reyk 1685:
1686: if (!WIFEXITED(status))
1687: return (1);
1688:
1689: return (WEXITSTATUS(status));
1.266 jcs 1690: }
1691:
1692: void
1.328 djm 1693: maybe_add_key_to_agent(const char *authfile, struct sshkey *private,
1694: const char *comment, const char *passphrase)
1.266 jcs 1695: {
1696: int auth_sock = -1, r;
1.321 djm 1697: const char *skprovider = NULL;
1.266 jcs 1698:
1699: if (options.add_keys_to_agent == 0)
1700: return;
1701:
1702: if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) {
1703: debug3("no authentication agent, not adding key");
1704: return;
1705: }
1706:
1707: if (options.add_keys_to_agent == 2 &&
1708: !ask_permission("Add key %s (%s) to agent?", authfile, comment)) {
1709: debug3("user denied adding this key");
1.273 dtucker 1710: close(auth_sock);
1.266 jcs 1711: return;
1712: }
1.322 markus 1713: if (sshkey_is_sk(private))
1.321 djm 1714: skprovider = options.sk_provider;
1.328 djm 1715: if ((r = ssh_add_identity_constrained(auth_sock, private,
1.331 djm 1716: comment == NULL ? authfile : comment,
1717: options.add_keys_to_agent_lifespan,
1.356 djm 1718: (options.add_keys_to_agent == 3), 0, skprovider, NULL, 0)) == 0)
1.266 jcs 1719: debug("identity added to agent: %s", authfile);
1720: else
1721: debug("could not add identity to agent: %s (%d)", authfile, r);
1.273 dtucker 1722: close(auth_sock);
1.1 deraadt 1723: }
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