]>
Commit | Line | Data |
---|---|---|
8efc0c15 | 1 | /* |
5260325f | 2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
4 | * All rights reserved | |
5 | * Created: Sat Mar 18 16:36:11 1995 ylo | |
6 | * Ssh client program. This program can be used to log into a remote machine. | |
7 | * The software supports strong authentication, encryption, and forwarding | |
8 | * of X11, TCP/IP, and authentication connections. | |
9 | * | |
10 | * Modified to work with SSL by Niels Provos <provos@citi.umich.edu> in Canada. | |
11 | */ | |
8efc0c15 | 12 | |
13 | #include "includes.h" | |
14 | RCSID("$Id$"); | |
15 | ||
16 | #include "xmalloc.h" | |
17 | #include "ssh.h" | |
18 | #include "packet.h" | |
19 | #include "buffer.h" | |
20 | #include "authfd.h" | |
21 | #include "readconf.h" | |
22 | #include "uidswap.h" | |
8ce64345 | 23 | |
24 | #include "ssh2.h" | |
25 | #include "compat.h" | |
7368a6c8 | 26 | #include "channels.h" |
8efc0c15 | 27 | |
f601d847 | 28 | #ifdef HAVE___PROGNAME |
29 | extern char *__progname; | |
30 | #else /* HAVE___PROGNAME */ | |
31 | const char *__progname = "ssh"; | |
32 | #endif /* HAVE___PROGNAME */ | |
33 | ||
48e671d5 | 34 | /* Flag indicating whether IPv4 or IPv6. This can be set on the command line. |
35 | Default value is AF_UNSPEC means both IPv4 and IPv6. */ | |
59e76f33 | 36 | #ifdef IPV4_DEFAULT |
37 | int IPv4or6 = AF_INET; | |
38 | #else | |
48e671d5 | 39 | int IPv4or6 = AF_UNSPEC; |
59e76f33 | 40 | #endif |
48e671d5 | 41 | |
5260325f | 42 | /* Flag indicating whether debug mode is on. This can be set on the command line. */ |
8efc0c15 | 43 | int debug_flag = 0; |
44 | ||
a8be9f80 | 45 | /* Flag indicating whether a tty should be allocated */ |
8efc0c15 | 46 | int tty_flag = 0; |
47 | ||
8ce64345 | 48 | /* don't exec a shell */ |
49 | int no_shell_flag = 0; | |
50 | int no_tty_flag = 0; | |
51 | ||
aa3378df | 52 | /* |
53 | * Flag indicating that nothing should be read from stdin. This can be set | |
54 | * on the command line. | |
55 | */ | |
8efc0c15 | 56 | int stdin_null_flag = 0; |
57 | ||
aa3378df | 58 | /* |
59 | * Flag indicating that ssh should fork after authentication. This is useful | |
60 | * so that the pasphrase can be entered manually, and then ssh goes to the | |
61 | * background. | |
62 | */ | |
8efc0c15 | 63 | int fork_after_authentication_flag = 0; |
64 | ||
aa3378df | 65 | /* |
66 | * General data structure for command line options and options configurable | |
67 | * in configuration files. See readconf.h. | |
68 | */ | |
8efc0c15 | 69 | Options options; |
70 | ||
aa3378df | 71 | /* |
72 | * Name of the host we are connecting to. This is the name given on the | |
73 | * command line, or the HostName specified for the user-supplied name in a | |
74 | * configuration file. | |
75 | */ | |
8efc0c15 | 76 | char *host; |
77 | ||
78 | /* socket address the host resolves to */ | |
48e671d5 | 79 | struct sockaddr_storage hostaddr; |
8efc0c15 | 80 | |
aa3378df | 81 | /* |
82 | * Flag to indicate that we have received a window change signal which has | |
83 | * not yet been processed. This will cause a message indicating the new | |
84 | * window size to be sent to the server a little later. This is volatile | |
85 | * because this is updated in a signal handler. | |
86 | */ | |
8efc0c15 | 87 | volatile int received_window_change_signal = 0; |
88 | ||
89 | /* Value of argv[0] (set in the main program). */ | |
90 | char *av0; | |
91 | ||
92 | /* Flag indicating whether we have a valid host private key loaded. */ | |
93 | int host_private_key_loaded = 0; | |
94 | ||
95 | /* Host private key. */ | |
96 | RSA *host_private_key = NULL; | |
97 | ||
98 | /* Original real UID. */ | |
99 | uid_t original_real_uid; | |
100 | ||
8ce64345 | 101 | /* command to be executed */ |
102 | Buffer command; | |
103 | ||
8efc0c15 | 104 | /* Prints a help message to the user. This function never returns. */ |
105 | ||
106 | void | |
107 | usage() | |
108 | { | |
5260325f | 109 | fprintf(stderr, "Usage: %s [options] host [command]\n", av0); |
110 | fprintf(stderr, "Options:\n"); | |
111 | fprintf(stderr, " -l user Log in using this user name.\n"); | |
112 | fprintf(stderr, " -n Redirect input from /dev/null.\n"); | |
113 | fprintf(stderr, " -a Disable authentication agent forwarding.\n"); | |
8efc0c15 | 114 | #ifdef AFS |
5260325f | 115 | fprintf(stderr, " -k Disable Kerberos ticket and AFS token forwarding.\n"); |
116 | #endif /* AFS */ | |
117 | fprintf(stderr, " -x Disable X11 connection forwarding.\n"); | |
118 | fprintf(stderr, " -i file Identity for RSA authentication (default: ~/.ssh/identity).\n"); | |
119 | fprintf(stderr, " -t Tty; allocate a tty even if command is given.\n"); | |
8ce64345 | 120 | fprintf(stderr, " -T Do not allocate a tty.\n"); |
5260325f | 121 | fprintf(stderr, " -v Verbose; display verbose debugging messages.\n"); |
122 | fprintf(stderr, " -V Display version number only.\n"); | |
123 | fprintf(stderr, " -P Don't allocate a privileged port.\n"); | |
124 | fprintf(stderr, " -q Quiet; don't display any warning messages.\n"); | |
125 | fprintf(stderr, " -f Fork into background after authentication.\n"); | |
126 | fprintf(stderr, " -e char Set escape character; ``none'' = disable (default: ~).\n"); | |
127 | ||
128 | fprintf(stderr, " -c cipher Select encryption algorithm: " | |
129 | "``3des'', " | |
130 | "``blowfish''\n"); | |
131 | fprintf(stderr, " -p port Connect to this port. Server must be on the same port.\n"); | |
132 | fprintf(stderr, " -L listen-port:host:port Forward local port to remote address\n"); | |
133 | fprintf(stderr, " -R listen-port:host:port Forward remote port to local address\n"); | |
134 | fprintf(stderr, " These cause %s to listen for connections on a port, and\n", av0); | |
135 | fprintf(stderr, " forward them to the other side by connecting to host:port.\n"); | |
136 | fprintf(stderr, " -C Enable compression.\n"); | |
8ce64345 | 137 | fprintf(stderr, " -N Do not execute a shell or command.\n"); |
5260325f | 138 | fprintf(stderr, " -g Allow remote hosts to connect to forwarded ports.\n"); |
48e671d5 | 139 | fprintf(stderr, " -4 Use IPv4 only.\n"); |
140 | fprintf(stderr, " -6 Use IPv6 only.\n"); | |
5260325f | 141 | fprintf(stderr, " -o 'option' Process the option as if it was read from a configuration file.\n"); |
142 | exit(1); | |
8efc0c15 | 143 | } |
144 | ||
5260325f | 145 | /* |
146 | * Connects to the given host using rsh (or prints an error message and exits | |
147 | * if rsh is not available). This function never returns. | |
148 | */ | |
8efc0c15 | 149 | void |
5260325f | 150 | rsh_connect(char *host, char *user, Buffer * command) |
8efc0c15 | 151 | { |
5260325f | 152 | char *args[10]; |
153 | int i; | |
154 | ||
155 | log("Using rsh. WARNING: Connection will not be encrypted."); | |
156 | /* Build argument list for rsh. */ | |
157 | i = 0; | |
158 | args[i++] = _PATH_RSH; | |
159 | /* host may have to come after user on some systems */ | |
160 | args[i++] = host; | |
161 | if (user) { | |
162 | args[i++] = "-l"; | |
163 | args[i++] = user; | |
164 | } | |
165 | if (buffer_len(command) > 0) { | |
166 | buffer_append(command, "\0", 1); | |
167 | args[i++] = buffer_ptr(command); | |
168 | } | |
169 | args[i++] = NULL; | |
170 | if (debug_flag) { | |
171 | for (i = 0; args[i]; i++) { | |
172 | if (i != 0) | |
173 | fprintf(stderr, " "); | |
174 | fprintf(stderr, "%s", args[i]); | |
175 | } | |
176 | fprintf(stderr, "\n"); | |
8efc0c15 | 177 | } |
5260325f | 178 | execv(_PATH_RSH, args); |
179 | perror(_PATH_RSH); | |
180 | exit(1); | |
8efc0c15 | 181 | } |
182 | ||
8ce64345 | 183 | int ssh_session(void); |
184 | int ssh_session2(void); | |
185 | ||
5260325f | 186 | /* |
187 | * Main program for the ssh client. | |
188 | */ | |
8efc0c15 | 189 | int |
190 | main(int ac, char **av) | |
191 | { | |
8ce64345 | 192 | int i, opt, optind, exit_status, ok; |
57112b5a | 193 | u_short fwd_port, fwd_host_port; |
5260325f | 194 | char *optarg, *cp, buf[256]; |
5260325f | 195 | struct stat st; |
196 | struct passwd *pw, pwcopy; | |
8ce64345 | 197 | int dummy; |
5260325f | 198 | uid_t original_effective_uid; |
5260325f | 199 | |
aa3378df | 200 | /* |
201 | * Save the original real uid. It will be needed later (uid-swapping | |
202 | * may clobber the real uid). | |
203 | */ | |
5260325f | 204 | original_real_uid = getuid(); |
205 | original_effective_uid = geteuid(); | |
206 | ||
207 | /* If we are installed setuid root be careful to not drop core. */ | |
208 | if (original_real_uid != original_effective_uid) { | |
209 | struct rlimit rlim; | |
210 | rlim.rlim_cur = rlim.rlim_max = 0; | |
211 | if (setrlimit(RLIMIT_CORE, &rlim) < 0) | |
212 | fatal("setrlimit failed: %.100s", strerror(errno)); | |
8efc0c15 | 213 | } |
aa3378df | 214 | /* |
215 | * Use uid-swapping to give up root privileges for the duration of | |
216 | * option processing. We will re-instantiate the rights when we are | |
217 | * ready to create the privileged port, and will permanently drop | |
218 | * them when the port has been created (actually, when the connection | |
219 | * has been made, as we may need to create the port several times). | |
220 | */ | |
5260325f | 221 | temporarily_use_uid(original_real_uid); |
222 | ||
aa3378df | 223 | /* |
224 | * Set our umask to something reasonable, as some files are created | |
225 | * with the default umask. This will make them world-readable but | |
226 | * writable only by the owner, which is ok for all files for which we | |
227 | * don't set the modes explicitly. | |
228 | */ | |
5260325f | 229 | umask(022); |
230 | ||
231 | /* Save our own name. */ | |
232 | av0 = av[0]; | |
233 | ||
234 | /* Initialize option structure to indicate that no values have been set. */ | |
235 | initialize_options(&options); | |
236 | ||
237 | /* Parse command-line arguments. */ | |
238 | host = NULL; | |
239 | ||
240 | /* If program name is not one of the standard names, use it as host name. */ | |
241 | if (strchr(av0, '/')) | |
242 | cp = strrchr(av0, '/') + 1; | |
243 | else | |
244 | cp = av0; | |
245 | if (strcmp(cp, "rsh") != 0 && strcmp(cp, "ssh") != 0 && | |
246 | strcmp(cp, "rlogin") != 0 && strcmp(cp, "slogin") != 0) | |
247 | host = cp; | |
248 | ||
249 | for (optind = 1; optind < ac; optind++) { | |
250 | if (av[optind][0] != '-') { | |
251 | if (host) | |
252 | break; | |
253 | if ((cp = strchr(av[optind], '@'))) { | |
48e671d5 | 254 | if(cp == av[optind]) |
255 | usage(); | |
5260325f | 256 | options.user = av[optind]; |
257 | *cp = '\0'; | |
258 | host = ++cp; | |
259 | } else | |
260 | host = av[optind]; | |
261 | continue; | |
262 | } | |
263 | opt = av[optind][1]; | |
264 | if (!opt) | |
265 | usage(); | |
266 | if (strchr("eilcpLRo", opt)) { /* options with arguments */ | |
267 | optarg = av[optind] + 2; | |
268 | if (strcmp(optarg, "") == 0) { | |
269 | if (optind >= ac - 1) | |
270 | usage(); | |
271 | optarg = av[++optind]; | |
272 | } | |
273 | } else { | |
274 | if (av[optind][2]) | |
275 | usage(); | |
276 | optarg = NULL; | |
277 | } | |
278 | switch (opt) { | |
48e671d5 | 279 | case '4': |
280 | IPv4or6 = AF_INET; | |
281 | break; | |
282 | ||
283 | case '6': | |
284 | IPv4or6 = AF_INET6; | |
285 | break; | |
286 | ||
5260325f | 287 | case 'n': |
288 | stdin_null_flag = 1; | |
289 | break; | |
290 | ||
291 | case 'f': | |
292 | fork_after_authentication_flag = 1; | |
293 | stdin_null_flag = 1; | |
294 | break; | |
295 | ||
296 | case 'x': | |
297 | options.forward_x11 = 0; | |
298 | break; | |
299 | ||
300 | case 'X': | |
301 | options.forward_x11 = 1; | |
302 | break; | |
303 | ||
304 | case 'g': | |
305 | options.gateway_ports = 1; | |
306 | break; | |
307 | ||
308 | case 'P': | |
309 | options.use_privileged_port = 0; | |
310 | break; | |
311 | ||
312 | case 'a': | |
313 | options.forward_agent = 0; | |
314 | break; | |
315 | #ifdef AFS | |
316 | case 'k': | |
317 | options.kerberos_tgt_passing = 0; | |
318 | options.afs_token_passing = 0; | |
319 | break; | |
320 | #endif | |
321 | case 'i': | |
322 | if (stat(optarg, &st) < 0) { | |
323 | fprintf(stderr, "Warning: Identity file %s does not exist.\n", | |
324 | optarg); | |
325 | break; | |
326 | } | |
327 | if (options.num_identity_files >= SSH_MAX_IDENTITY_FILES) | |
328 | fatal("Too many identity files specified (max %d)", | |
329 | SSH_MAX_IDENTITY_FILES); | |
330 | options.identity_files[options.num_identity_files++] = | |
331 | xstrdup(optarg); | |
332 | break; | |
333 | ||
334 | case 't': | |
335 | tty_flag = 1; | |
336 | break; | |
337 | ||
338 | case 'v': | |
339 | case 'V': | |
a8be9f80 | 340 | fprintf(stderr, "SSH Version %s, protocol versions %d.%d/%d.%d.\n", |
341 | SSH_VERSION, | |
342 | PROTOCOL_MAJOR_1, PROTOCOL_MINOR_1, | |
343 | PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2); | |
8ce64345 | 344 | fprintf(stderr, "Compiled with SSL (0x%8.8lx).\n", SSLeay()); |
5260325f | 345 | if (opt == 'V') |
346 | exit(0); | |
347 | debug_flag = 1; | |
348 | options.log_level = SYSLOG_LEVEL_DEBUG; | |
349 | break; | |
350 | ||
351 | case 'q': | |
352 | options.log_level = SYSLOG_LEVEL_QUIET; | |
353 | break; | |
354 | ||
355 | case 'e': | |
356 | if (optarg[0] == '^' && optarg[2] == 0 && | |
357 | (unsigned char) optarg[1] >= 64 && (unsigned char) optarg[1] < 128) | |
358 | options.escape_char = (unsigned char) optarg[1] & 31; | |
359 | else if (strlen(optarg) == 1) | |
360 | options.escape_char = (unsigned char) optarg[0]; | |
361 | else if (strcmp(optarg, "none") == 0) | |
362 | options.escape_char = -2; | |
363 | else { | |
364 | fprintf(stderr, "Bad escape character '%s'.\n", optarg); | |
365 | exit(1); | |
366 | } | |
367 | break; | |
368 | ||
369 | case 'c': | |
370 | options.cipher = cipher_number(optarg); | |
371 | if (options.cipher == -1) { | |
372 | fprintf(stderr, "Unknown cipher type '%s'\n", optarg); | |
373 | exit(1); | |
374 | } | |
375 | break; | |
376 | ||
377 | case 'p': | |
378 | options.port = atoi(optarg); | |
5260325f | 379 | break; |
380 | ||
381 | case 'l': | |
382 | options.user = optarg; | |
383 | break; | |
384 | ||
385 | case 'R': | |
48e671d5 | 386 | if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf, |
387 | &fwd_host_port) != 3 && | |
388 | sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf, | |
389 | &fwd_host_port) != 3) { | |
5260325f | 390 | fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg); |
391 | usage(); | |
392 | /* NOTREACHED */ | |
393 | } | |
394 | add_remote_forward(&options, fwd_port, buf, fwd_host_port); | |
395 | break; | |
396 | ||
397 | case 'L': | |
48e671d5 | 398 | if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf, |
399 | &fwd_host_port) != 3 && | |
400 | sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf, | |
401 | &fwd_host_port) != 3) { | |
5260325f | 402 | fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg); |
403 | usage(); | |
404 | /* NOTREACHED */ | |
405 | } | |
406 | add_local_forward(&options, fwd_port, buf, fwd_host_port); | |
407 | break; | |
408 | ||
409 | case 'C': | |
410 | options.compression = 1; | |
411 | break; | |
412 | ||
8ce64345 | 413 | case 'N': |
414 | no_shell_flag = 1; | |
415 | no_tty_flag = 1; | |
416 | break; | |
417 | ||
418 | case 'T': | |
419 | no_tty_flag = 1; | |
420 | break; | |
421 | ||
5260325f | 422 | case 'o': |
423 | dummy = 1; | |
424 | if (process_config_line(&options, host ? host : "", optarg, | |
425 | "command-line", 0, &dummy) != 0) | |
426 | exit(1); | |
427 | break; | |
428 | ||
429 | default: | |
430 | usage(); | |
431 | } | |
432 | } | |
433 | ||
434 | /* Check that we got a host name. */ | |
435 | if (!host) | |
8efc0c15 | 436 | usage(); |
5260325f | 437 | |
438 | /* check if RSA support exists */ | |
439 | if (rsa_alive() == 0) { | |
440 | fprintf(stderr, | |
441 | "%s: no RSA support in libssl and libcrypto. See ssl(8).\n", | |
442 | __progname); | |
443 | exit(1); | |
8efc0c15 | 444 | } |
5260325f | 445 | /* Initialize the command to execute on remote host. */ |
446 | buffer_init(&command); | |
447 | ||
aa3378df | 448 | /* |
449 | * Save the command to execute on the remote host in a buffer. There | |
450 | * is no limit on the length of the command, except by the maximum | |
451 | * packet size. Also sets the tty flag if there is no command. | |
452 | */ | |
5260325f | 453 | if (optind == ac) { |
454 | /* No command specified - execute shell on a tty. */ | |
455 | tty_flag = 1; | |
456 | } else { | |
457 | /* A command has been specified. Store it into the | |
458 | buffer. */ | |
459 | for (i = optind; i < ac; i++) { | |
460 | if (i > optind) | |
461 | buffer_append(&command, " ", 1); | |
462 | buffer_append(&command, av[i], strlen(av[i])); | |
463 | } | |
8efc0c15 | 464 | } |
5260325f | 465 | |
466 | /* Cannot fork to background if no command. */ | |
467 | if (fork_after_authentication_flag && buffer_len(&command) == 0) | |
468 | fatal("Cannot fork into background without a command to execute."); | |
469 | ||
470 | /* Allocate a tty by default if no command specified. */ | |
471 | if (buffer_len(&command) == 0) | |
472 | tty_flag = 1; | |
473 | ||
474 | /* Do not allocate a tty if stdin is not a tty. */ | |
475 | if (!isatty(fileno(stdin))) { | |
476 | if (tty_flag) | |
477 | fprintf(stderr, "Pseudo-terminal will not be allocated because stdin is not a terminal.\n"); | |
478 | tty_flag = 0; | |
479 | } | |
8ce64345 | 480 | /* force */ |
481 | if (no_tty_flag) | |
482 | tty_flag = 0; | |
483 | ||
5260325f | 484 | /* Get user data. */ |
485 | pw = getpwuid(original_real_uid); | |
486 | if (!pw) { | |
487 | fprintf(stderr, "You don't exist, go away!\n"); | |
488 | exit(1); | |
489 | } | |
490 | /* Take a copy of the returned structure. */ | |
491 | memset(&pwcopy, 0, sizeof(pwcopy)); | |
492 | pwcopy.pw_name = xstrdup(pw->pw_name); | |
493 | pwcopy.pw_passwd = xstrdup(pw->pw_passwd); | |
494 | pwcopy.pw_uid = pw->pw_uid; | |
495 | pwcopy.pw_gid = pw->pw_gid; | |
496 | pwcopy.pw_dir = xstrdup(pw->pw_dir); | |
497 | pwcopy.pw_shell = xstrdup(pw->pw_shell); | |
498 | pw = &pwcopy; | |
499 | ||
500 | /* Initialize "log" output. Since we are the client all output | |
501 | actually goes to the terminal. */ | |
502 | log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0); | |
503 | ||
504 | /* Read per-user configuration file. */ | |
505 | snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, SSH_USER_CONFFILE); | |
506 | read_config_file(buf, host, &options); | |
507 | ||
508 | /* Read systemwide configuration file. */ | |
509 | read_config_file(HOST_CONFIG_FILE, host, &options); | |
510 | ||
511 | /* Fill configuration defaults. */ | |
512 | fill_default_options(&options); | |
513 | ||
514 | /* reinit */ | |
515 | log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0); | |
516 | ||
517 | if (options.user == NULL) | |
518 | options.user = xstrdup(pw->pw_name); | |
519 | ||
520 | if (options.hostname != NULL) | |
521 | host = options.hostname; | |
522 | ||
523 | /* Find canonic host name. */ | |
524 | if (strchr(host, '.') == 0) { | |
48e671d5 | 525 | struct addrinfo hints; |
526 | struct addrinfo *ai = NULL; | |
527 | int errgai; | |
528 | memset(&hints, 0, sizeof(hints)); | |
c8d54615 | 529 | hints.ai_family = IPv4or6; |
48e671d5 | 530 | hints.ai_flags = AI_CANONNAME; |
531 | hints.ai_socktype = SOCK_STREAM; | |
532 | errgai = getaddrinfo(host, NULL, &hints, &ai); | |
533 | if (errgai == 0) { | |
534 | if (ai->ai_canonname != NULL) | |
535 | host = xstrdup(ai->ai_canonname); | |
536 | freeaddrinfo(ai); | |
8efc0c15 | 537 | } |
8efc0c15 | 538 | } |
5260325f | 539 | /* Disable rhosts authentication if not running as root. */ |
540 | if (original_effective_uid != 0 || !options.use_privileged_port) { | |
541 | options.rhosts_authentication = 0; | |
542 | options.rhosts_rsa_authentication = 0; | |
543 | } | |
aa3378df | 544 | /* |
545 | * If using rsh has been selected, exec it now (without trying | |
546 | * anything else). Note that we must release privileges first. | |
547 | */ | |
5260325f | 548 | if (options.use_rsh) { |
aa3378df | 549 | /* |
550 | * Restore our superuser privileges. This must be done | |
551 | * before permanently setting the uid. | |
552 | */ | |
5260325f | 553 | restore_uid(); |
554 | ||
555 | /* Switch to the original uid permanently. */ | |
556 | permanently_set_uid(original_real_uid); | |
557 | ||
558 | /* Execute rsh. */ | |
559 | rsh_connect(host, options.user, &command); | |
560 | fatal("rsh_connect returned"); | |
8efc0c15 | 561 | } |
5260325f | 562 | /* Restore our superuser privileges. */ |
563 | restore_uid(); | |
564 | ||
aa3378df | 565 | /* |
566 | * Open a connection to the remote host. This needs root privileges | |
567 | * if rhosts_{rsa_}authentication is enabled. | |
568 | */ | |
5260325f | 569 | |
570 | ok = ssh_connect(host, &hostaddr, options.port, | |
571 | options.connection_attempts, | |
572 | !options.rhosts_authentication && | |
573 | !options.rhosts_rsa_authentication, | |
574 | original_real_uid, | |
575 | options.proxy_command); | |
576 | ||
aa3378df | 577 | /* |
578 | * If we successfully made the connection, load the host private key | |
579 | * in case we will need it later for combined rsa-rhosts | |
580 | * authentication. This must be done before releasing extra | |
581 | * privileges, because the file is only readable by root. | |
582 | */ | |
5260325f | 583 | if (ok) { |
584 | host_private_key = RSA_new(); | |
585 | if (load_private_key(HOST_KEY_FILE, "", host_private_key, NULL)) | |
586 | host_private_key_loaded = 1; | |
587 | } | |
aa3378df | 588 | /* |
589 | * Get rid of any extra privileges that we may have. We will no | |
590 | * longer need them. Also, extra privileges could make it very hard | |
591 | * to read identity files and other non-world-readable files from the | |
592 | * user's home directory if it happens to be on a NFS volume where | |
593 | * root is mapped to nobody. | |
594 | */ | |
595 | ||
596 | /* | |
597 | * Note that some legacy systems need to postpone the following call | |
598 | * to permanently_set_uid() until the private hostkey is destroyed | |
599 | * with RSA_free(). Otherwise the calling user could ptrace() the | |
600 | * process, read the private hostkey and impersonate the host. | |
601 | * OpenBSD does not allow ptracing of setuid processes. | |
602 | */ | |
5260325f | 603 | permanently_set_uid(original_real_uid); |
604 | ||
aa3378df | 605 | /* |
606 | * Now that we are back to our own permissions, create ~/.ssh | |
607 | * directory if it doesn\'t already exist. | |
608 | */ | |
5260325f | 609 | snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, SSH_USER_DIR); |
610 | if (stat(buf, &st) < 0) | |
611 | if (mkdir(buf, 0755) < 0) | |
612 | error("Could not create directory '%.200s'.", buf); | |
613 | ||
614 | /* Check if the connection failed, and try "rsh" if appropriate. */ | |
615 | if (!ok) { | |
616 | if (options.port != 0) | |
57112b5a | 617 | log("Secure connection to %.100s on port %hu refused%.100s.", |
5260325f | 618 | host, options.port, |
619 | options.fallback_to_rsh ? "; reverting to insecure method" : ""); | |
620 | else | |
621 | log("Secure connection to %.100s refused%.100s.", host, | |
622 | options.fallback_to_rsh ? "; reverting to insecure method" : ""); | |
623 | ||
624 | if (options.fallback_to_rsh) { | |
625 | rsh_connect(host, options.user, &command); | |
626 | fatal("rsh_connect returned"); | |
627 | } | |
628 | exit(1); | |
8efc0c15 | 629 | } |
5260325f | 630 | /* Expand ~ in options.identity_files. */ |
631 | for (i = 0; i < options.num_identity_files; i++) | |
632 | options.identity_files[i] = | |
633 | tilde_expand_filename(options.identity_files[i], original_real_uid); | |
634 | ||
635 | /* Expand ~ in known host file names. */ | |
636 | options.system_hostfile = tilde_expand_filename(options.system_hostfile, | |
637 | original_real_uid); | |
638 | options.user_hostfile = tilde_expand_filename(options.user_hostfile, | |
639 | original_real_uid); | |
640 | ||
641 | /* Log into the remote system. This never returns if the login fails. */ | |
642 | ssh_login(host_private_key_loaded, host_private_key, | |
48e671d5 | 643 | host, (struct sockaddr *)&hostaddr, original_real_uid); |
5260325f | 644 | |
645 | /* We no longer need the host private key. Clear it now. */ | |
646 | if (host_private_key_loaded) | |
647 | RSA_free(host_private_key); /* Destroys contents safely */ | |
648 | ||
8ce64345 | 649 | exit_status = compat20 ? ssh_session2() : ssh_session(); |
650 | packet_close(); | |
651 | return exit_status; | |
652 | } | |
653 | ||
654 | int | |
655 | ssh_session(void) | |
656 | { | |
657 | int type; | |
658 | int i; | |
659 | int plen; | |
660 | int interactive = 0; | |
661 | int have_tty = 0; | |
662 | struct winsize ws; | |
663 | int authfd; | |
664 | char *cp; | |
665 | ||
5260325f | 666 | /* Enable compression if requested. */ |
667 | if (options.compression) { | |
668 | debug("Requesting compression at level %d.", options.compression_level); | |
669 | ||
670 | if (options.compression_level < 1 || options.compression_level > 9) | |
671 | fatal("Compression level must be from 1 (fast) to 9 (slow, best)."); | |
672 | ||
673 | /* Send the request. */ | |
674 | packet_start(SSH_CMSG_REQUEST_COMPRESSION); | |
675 | packet_put_int(options.compression_level); | |
676 | packet_send(); | |
677 | packet_write_wait(); | |
678 | type = packet_read(&plen); | |
679 | if (type == SSH_SMSG_SUCCESS) | |
680 | packet_start_compression(options.compression_level); | |
681 | else if (type == SSH_SMSG_FAILURE) | |
682 | log("Warning: Remote host refused compression."); | |
683 | else | |
684 | packet_disconnect("Protocol error waiting for compression response."); | |
685 | } | |
686 | /* Allocate a pseudo tty if appropriate. */ | |
687 | if (tty_flag) { | |
688 | debug("Requesting pty."); | |
689 | ||
690 | /* Start the packet. */ | |
691 | packet_start(SSH_CMSG_REQUEST_PTY); | |
692 | ||
693 | /* Store TERM in the packet. There is no limit on the | |
694 | length of the string. */ | |
695 | cp = getenv("TERM"); | |
696 | if (!cp) | |
697 | cp = ""; | |
698 | packet_put_string(cp, strlen(cp)); | |
699 | ||
700 | /* Store window size in the packet. */ | |
701 | if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) | |
702 | memset(&ws, 0, sizeof(ws)); | |
703 | packet_put_int(ws.ws_row); | |
704 | packet_put_int(ws.ws_col); | |
705 | packet_put_int(ws.ws_xpixel); | |
706 | packet_put_int(ws.ws_ypixel); | |
707 | ||
708 | /* Store tty modes in the packet. */ | |
709 | tty_make_modes(fileno(stdin)); | |
710 | ||
711 | /* Send the packet, and wait for it to leave. */ | |
712 | packet_send(); | |
713 | packet_write_wait(); | |
714 | ||
715 | /* Read response from the server. */ | |
716 | type = packet_read(&plen); | |
4fe2af09 | 717 | if (type == SSH_SMSG_SUCCESS) { |
5260325f | 718 | interactive = 1; |
8ce64345 | 719 | have_tty = 1; |
4fe2af09 | 720 | } else if (type == SSH_SMSG_FAILURE) |
5260325f | 721 | log("Warning: Remote host failed or refused to allocate a pseudo tty."); |
722 | else | |
723 | packet_disconnect("Protocol error waiting for pty request response."); | |
724 | } | |
725 | /* Request X11 forwarding if enabled and DISPLAY is set. */ | |
726 | if (options.forward_x11 && getenv("DISPLAY") != NULL) { | |
727 | char line[512], proto[512], data[512]; | |
728 | FILE *f; | |
729 | int forwarded = 0, got_data = 0, i; | |
8efc0c15 | 730 | |
731 | #ifdef XAUTH_PATH | |
5260325f | 732 | /* Try to get Xauthority information for the display. */ |
733 | snprintf(line, sizeof line, "%.100s list %.200s 2>/dev/null", | |
734 | XAUTH_PATH, getenv("DISPLAY")); | |
735 | f = popen(line, "r"); | |
736 | if (f && fgets(line, sizeof(line), f) && | |
737 | sscanf(line, "%*s %s %s", proto, data) == 2) | |
738 | got_data = 1; | |
739 | if (f) | |
740 | pclose(f); | |
8efc0c15 | 741 | #endif /* XAUTH_PATH */ |
aa3378df | 742 | /* |
743 | * If we didn't get authentication data, just make up some | |
744 | * data. The forwarding code will check the validity of the | |
745 | * response anyway, and substitute this data. The X11 | |
746 | * server, however, will ignore this fake data and use | |
747 | * whatever authentication mechanisms it was using otherwise | |
748 | * for the local connection. | |
749 | */ | |
5260325f | 750 | if (!got_data) { |
751 | u_int32_t rand = 0; | |
752 | ||
753 | strlcpy(proto, "MIT-MAGIC-COOKIE-1", sizeof proto); | |
754 | for (i = 0; i < 16; i++) { | |
755 | if (i % 4 == 0) | |
756 | rand = arc4random(); | |
757 | snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", rand & 0xff); | |
758 | rand >>= 8; | |
759 | } | |
760 | } | |
aa3378df | 761 | /* |
762 | * Got local authentication reasonable information. Request | |
763 | * forwarding with authentication spoofing. | |
764 | */ | |
5260325f | 765 | debug("Requesting X11 forwarding with authentication spoofing."); |
766 | x11_request_forwarding_with_spoofing(proto, data); | |
767 | ||
768 | /* Read response from the server. */ | |
769 | type = packet_read(&plen); | |
770 | if (type == SSH_SMSG_SUCCESS) { | |
771 | forwarded = 1; | |
772 | interactive = 1; | |
773 | } else if (type == SSH_SMSG_FAILURE) | |
774 | log("Warning: Remote host denied X11 forwarding."); | |
775 | else | |
776 | packet_disconnect("Protocol error waiting for X11 forwarding"); | |
777 | } | |
778 | /* Tell the packet module whether this is an interactive session. */ | |
779 | packet_set_interactive(interactive, options.keepalives); | |
780 | ||
781 | /* Clear agent forwarding if we don\'t have an agent. */ | |
782 | authfd = ssh_get_authentication_socket(); | |
783 | if (authfd < 0) | |
784 | options.forward_agent = 0; | |
785 | else | |
786 | ssh_close_authentication_socket(authfd); | |
787 | ||
788 | /* Request authentication agent forwarding if appropriate. */ | |
789 | if (options.forward_agent) { | |
790 | debug("Requesting authentication agent forwarding."); | |
791 | auth_request_forwarding(); | |
792 | ||
793 | /* Read response from the server. */ | |
794 | type = packet_read(&plen); | |
795 | packet_integrity_check(plen, 0, type); | |
796 | if (type != SSH_SMSG_SUCCESS) | |
797 | log("Warning: Remote host denied authentication agent forwarding."); | |
798 | } | |
799 | /* Initiate local TCP/IP port forwardings. */ | |
800 | for (i = 0; i < options.num_local_forwards; i++) { | |
801 | debug("Connections to local port %d forwarded to remote address %.200s:%d", | |
802 | options.local_forwards[i].port, | |
803 | options.local_forwards[i].host, | |
804 | options.local_forwards[i].host_port); | |
805 | channel_request_local_forwarding(options.local_forwards[i].port, | |
806 | options.local_forwards[i].host, | |
95f1eccc | 807 | options.local_forwards[i].host_port, |
808 | options.gateway_ports); | |
8efc0c15 | 809 | } |
810 | ||
5260325f | 811 | /* Initiate remote TCP/IP port forwardings. */ |
812 | for (i = 0; i < options.num_remote_forwards; i++) { | |
813 | debug("Connections to remote port %d forwarded to local address %.200s:%d", | |
814 | options.remote_forwards[i].port, | |
815 | options.remote_forwards[i].host, | |
816 | options.remote_forwards[i].host_port); | |
817 | channel_request_remote_forwarding(options.remote_forwards[i].port, | |
818 | options.remote_forwards[i].host, | |
819 | options.remote_forwards[i].host_port); | |
8efc0c15 | 820 | } |
5260325f | 821 | |
aa3378df | 822 | /* If requested, let ssh continue in the background. */ |
823 | if (fork_after_authentication_flag) | |
824 | if (daemon(1, 1) < 0) | |
825 | fatal("daemon() failed: %.200s", strerror(errno)); | |
826 | ||
827 | /* | |
828 | * If a command was specified on the command line, execute the | |
829 | * command now. Otherwise request the server to start a shell. | |
830 | */ | |
5260325f | 831 | if (buffer_len(&command) > 0) { |
832 | int len = buffer_len(&command); | |
833 | if (len > 900) | |
834 | len = 900; | |
835 | debug("Sending command: %.*s", len, buffer_ptr(&command)); | |
836 | packet_start(SSH_CMSG_EXEC_CMD); | |
837 | packet_put_string(buffer_ptr(&command), buffer_len(&command)); | |
838 | packet_send(); | |
839 | packet_write_wait(); | |
840 | } else { | |
841 | debug("Requesting shell."); | |
842 | packet_start(SSH_CMSG_EXEC_SHELL); | |
843 | packet_send(); | |
844 | packet_write_wait(); | |
845 | } | |
846 | ||
847 | /* Enter the interactive session. */ | |
8ce64345 | 848 | return client_loop(have_tty, tty_flag ? options.escape_char : -1); |
849 | } | |
5260325f | 850 | |
8ce64345 | 851 | void |
852 | init_local_fwd(void) | |
853 | { | |
854 | int i; | |
855 | /* Initiate local TCP/IP port forwardings. */ | |
856 | for (i = 0; i < options.num_local_forwards; i++) { | |
857 | debug("Connections to local port %d forwarded to remote address %.200s:%d", | |
858 | options.local_forwards[i].port, | |
859 | options.local_forwards[i].host, | |
860 | options.local_forwards[i].host_port); | |
861 | channel_request_local_forwarding(options.local_forwards[i].port, | |
862 | options.local_forwards[i].host, | |
863 | options.local_forwards[i].host_port, | |
864 | options.gateway_ports); | |
865 | } | |
866 | } | |
867 | ||
868 | extern void client_set_session_ident(int id); | |
869 | ||
870 | void | |
871 | client_init(int id, void *arg) | |
872 | { | |
873 | int len; | |
874 | debug("client_init id %d arg %d", id, (int)arg); | |
875 | ||
876 | if (no_shell_flag) | |
877 | goto done; | |
878 | ||
879 | if (tty_flag) { | |
880 | struct winsize ws; | |
881 | char *cp; | |
882 | cp = getenv("TERM"); | |
883 | if (!cp) | |
884 | cp = ""; | |
885 | /* Store window size in the packet. */ | |
886 | if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) | |
887 | memset(&ws, 0, sizeof(ws)); | |
888 | ||
889 | channel_request_start(id, "pty-req", 0); | |
890 | packet_put_cstring(cp); | |
891 | packet_put_int(ws.ws_col); | |
892 | packet_put_int(ws.ws_row); | |
893 | packet_put_int(ws.ws_xpixel); | |
894 | packet_put_int(ws.ws_ypixel); | |
895 | packet_put_cstring(""); /* XXX: encode terminal modes */ | |
896 | packet_send(); | |
897 | /* XXX wait for reply */ | |
898 | } | |
899 | len = buffer_len(&command); | |
900 | if (len > 0) { | |
901 | if (len > 900) | |
902 | len = 900; | |
903 | debug("Sending command: %.*s", len, buffer_ptr(&command)); | |
904 | channel_request_start(id, "exec", 0); | |
905 | packet_put_string(buffer_ptr(&command), len); | |
906 | packet_send(); | |
907 | } else { | |
908 | channel_request(id, "shell", 0); | |
909 | } | |
910 | /* channel_callback(id, SSH2_MSG_OPEN_CONFIGMATION, client_init, 0); */ | |
911 | done: | |
912 | /* register different callback, etc. XXX */ | |
913 | client_set_session_ident(id); | |
914 | } | |
915 | ||
916 | int | |
917 | ssh_session2(void) | |
918 | { | |
919 | int window, packetmax, id; | |
920 | int in = dup(STDIN_FILENO); | |
921 | int out = dup(STDOUT_FILENO); | |
922 | int err = dup(STDERR_FILENO); | |
923 | ||
924 | if (in < 0 || out < 0 || err < 0) | |
925 | fatal("dump in/out/err failed"); | |
926 | ||
927 | /* should be pre-session */ | |
928 | init_local_fwd(); | |
929 | ||
930 | window = 32*1024; | |
931 | if (tty_flag) { | |
932 | packetmax = window/8; | |
933 | } else { | |
934 | window *= 2; | |
935 | packetmax = window/2; | |
936 | } | |
937 | ||
938 | id = channel_new( | |
939 | "session", SSH_CHANNEL_OPENING, in, out, err, | |
940 | window, packetmax, CHAN_EXTENDED_WRITE, xstrdup("client-session")); | |
941 | ||
942 | ||
943 | channel_open(id); | |
944 | channel_register_callback(id, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, client_init, (void *)0); | |
5260325f | 945 | |
8ce64345 | 946 | return client_loop(tty_flag, tty_flag ? options.escape_char : -1); |
8efc0c15 | 947 | } |