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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: Fri Mar 17 17:09:28 1995 ylo | |
6 | * This program is the ssh daemon. It listens for connections from clients, and | |
7 | * performs authentication, executes use commands or shell, and forwards | |
8 | * information to/from the application to the user client over an encrypted | |
9 | * connection. This can also handle forwarding of X11, TCP/IP, and authentication | |
10 | * agent connections. | |
11 | */ | |
8efc0c15 | 12 | |
13 | #include "includes.h" | |
14 | RCSID("$Id$"); | |
15 | ||
16 | #include "xmalloc.h" | |
17 | #include "rsa.h" | |
18 | #include "ssh.h" | |
19 | #include "pty.h" | |
20 | #include "packet.h" | |
21 | #include "buffer.h" | |
22 | #include "cipher.h" | |
23 | #include "mpaux.h" | |
24 | #include "servconf.h" | |
25 | #include "uidswap.h" | |
26 | #include "compat.h" | |
27 | ||
28 | #ifdef LIBWRAP | |
29 | #include <tcpd.h> | |
30 | #include <syslog.h> | |
31 | int allow_severity = LOG_INFO; | |
32 | int deny_severity = LOG_WARNING; | |
33 | #endif /* LIBWRAP */ | |
34 | ||
35 | #ifndef O_NOCTTY | |
36 | #define O_NOCTTY 0 | |
37 | #endif | |
38 | ||
8efc0c15 | 39 | /* Local Xauthority file. */ |
6a17f9c2 | 40 | static char *xauthfile = NULL; |
8efc0c15 | 41 | |
42 | /* Server configuration options. */ | |
43 | ServerOptions options; | |
44 | ||
45 | /* Name of the server configuration file. */ | |
46 | char *config_file_name = SERVER_CONFIG_FILE; | |
47 | ||
48e671d5 | 48 | /* |
49 | * Flag indicating whether IPv4 or IPv6. This can be set on the command line. | |
50 | * Default value is AF_UNSPEC means both IPv4 and IPv6. | |
51 | */ | |
59e76f33 | 52 | #ifdef IPV4_DEFAULT |
53 | int IPv4or6 = AF_INET; | |
54 | #else | |
48e671d5 | 55 | int IPv4or6 = AF_UNSPEC; |
59e76f33 | 56 | #endif |
48e671d5 | 57 | |
5260325f | 58 | /* |
59 | * Debug mode flag. This can be set on the command line. If debug | |
60 | * mode is enabled, extra debugging output will be sent to the system | |
61 | * log, the daemon will not go to background, and will exit after processing | |
62 | * the first connection. | |
63 | */ | |
8efc0c15 | 64 | int debug_flag = 0; |
65 | ||
66 | /* Flag indicating that the daemon is being started from inetd. */ | |
67 | int inetd_flag = 0; | |
68 | ||
6a17f9c2 | 69 | /* debug goes to stderr unless inetd_flag is set */ |
70 | int log_stderr = 0; | |
71 | ||
8efc0c15 | 72 | /* argv[0] without path. */ |
73 | char *av0; | |
74 | ||
75 | /* Saved arguments to main(). */ | |
76 | char **saved_argv; | |
77 | ||
aa3378df | 78 | /* |
48e671d5 | 79 | * The sockets that the server is listening; this is used in the SIGHUP |
80 | * signal handler. | |
aa3378df | 81 | */ |
48e671d5 | 82 | #define MAX_LISTEN_SOCKS 16 |
83 | int listen_socks[MAX_LISTEN_SOCKS]; | |
84 | int num_listen_socks = 0; | |
8efc0c15 | 85 | |
aa3378df | 86 | /* |
87 | * the client's version string, passed by sshd2 in compat mode. if != NULL, | |
88 | * sshd will skip the version-number exchange | |
89 | */ | |
5260325f | 90 | char *client_version_string = NULL; |
91 | ||
92 | /* Flags set in auth-rsa from authorized_keys flags. These are set in auth-rsa.c. */ | |
8efc0c15 | 93 | int no_port_forwarding_flag = 0; |
94 | int no_agent_forwarding_flag = 0; | |
95 | int no_x11_forwarding_flag = 0; | |
96 | int no_pty_flag = 0; | |
5260325f | 97 | |
98 | /* RSA authentication "command=" option. */ | |
99 | char *forced_command = NULL; | |
100 | ||
101 | /* RSA authentication "environment=" options. */ | |
102 | struct envstring *custom_environment = NULL; | |
8efc0c15 | 103 | |
104 | /* Session id for the current session. */ | |
105 | unsigned char session_id[16]; | |
106 | ||
aa3378df | 107 | /* |
108 | * Any really sensitive data in the application is contained in this | |
109 | * structure. The idea is that this structure could be locked into memory so | |
110 | * that the pages do not get written into swap. However, there are some | |
111 | * problems. The private key contains BIGNUMs, and we do not (in principle) | |
112 | * have access to the internals of them, and locking just the structure is | |
113 | * not very useful. Currently, memory locking is not implemented. | |
114 | */ | |
5260325f | 115 | struct { |
116 | RSA *private_key; /* Private part of server key. */ | |
117 | RSA *host_key; /* Private part of host key. */ | |
8efc0c15 | 118 | } sensitive_data; |
119 | ||
aa3378df | 120 | /* |
121 | * Flag indicating whether the current session key has been used. This flag | |
122 | * is set whenever the key is used, and cleared when the key is regenerated. | |
123 | */ | |
8efc0c15 | 124 | int key_used = 0; |
125 | ||
126 | /* This is set to true when SIGHUP is received. */ | |
127 | int received_sighup = 0; | |
128 | ||
129 | /* Public side of the server key. This value is regenerated regularly with | |
130 | the private key. */ | |
131 | RSA *public_key; | |
132 | ||
133 | /* Prototypes for various functions defined later in this file. */ | |
e7c0f9d5 | 134 | void do_connection(); |
135 | void do_authentication(char *user); | |
5260325f | 136 | void do_authloop(struct passwd * pw); |
e7c0f9d5 | 137 | void do_fake_authloop(char *user); |
5260325f | 138 | void do_authenticated(struct passwd * pw); |
139 | void do_exec_pty(const char *command, int ptyfd, int ttyfd, | |
140 | const char *ttyname, struct passwd * pw, const char *term, | |
141 | const char *display, const char *auth_proto, | |
142 | const char *auth_data); | |
143 | void do_exec_no_pty(const char *command, struct passwd * pw, | |
144 | const char *display, const char *auth_proto, | |
145 | const char *auth_data); | |
146 | void do_child(const char *command, struct passwd * pw, const char *term, | |
8efc0c15 | 147 | const char *display, const char *auth_proto, |
148 | const char *auth_data, const char *ttyname); | |
e7c0f9d5 | 149 | |
48e671d5 | 150 | /* |
151 | * Close all listening sockets | |
152 | */ | |
153 | void | |
154 | close_listen_socks(void) | |
155 | { | |
156 | int i; | |
157 | for (i = 0; i < num_listen_socks; i++) | |
158 | close(listen_socks[i]); | |
159 | num_listen_socks = -1; | |
160 | } | |
161 | ||
5260325f | 162 | /* |
163 | * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; | |
164 | * the effect is to reread the configuration file (and to regenerate | |
165 | * the server key). | |
166 | */ | |
167 | void | |
168 | sighup_handler(int sig) | |
8efc0c15 | 169 | { |
5260325f | 170 | received_sighup = 1; |
171 | signal(SIGHUP, sighup_handler); | |
8efc0c15 | 172 | } |
173 | ||
5260325f | 174 | /* |
175 | * Called from the main program after receiving SIGHUP. | |
176 | * Restarts the server. | |
177 | */ | |
178 | void | |
179 | sighup_restart() | |
8efc0c15 | 180 | { |
5260325f | 181 | log("Received SIGHUP; restarting."); |
48e671d5 | 182 | close_listen_socks(); |
5260325f | 183 | execv(saved_argv[0], saved_argv); |
184 | log("RESTART FAILED: av0='%s', error: %s.", av0, strerror(errno)); | |
185 | exit(1); | |
8efc0c15 | 186 | } |
187 | ||
5260325f | 188 | /* |
189 | * Generic signal handler for terminating signals in the master daemon. | |
190 | * These close the listen socket; not closing it seems to cause "Address | |
191 | * already in use" problems on some machines, which is inconvenient. | |
192 | */ | |
193 | void | |
194 | sigterm_handler(int sig) | |
8efc0c15 | 195 | { |
5260325f | 196 | log("Received signal %d; terminating.", sig); |
48e671d5 | 197 | close_listen_socks(); |
5260325f | 198 | exit(255); |
8efc0c15 | 199 | } |
200 | ||
5260325f | 201 | /* |
202 | * SIGCHLD handler. This is called whenever a child dies. This will then | |
203 | * reap any zombies left by exited c. | |
204 | */ | |
205 | void | |
206 | main_sigchld_handler(int sig) | |
8efc0c15 | 207 | { |
5260325f | 208 | int save_errno = errno; |
209 | int status; | |
5ad13cd7 | 210 | |
5260325f | 211 | while (waitpid(-1, &status, WNOHANG) > 0) |
212 | ; | |
5ad13cd7 | 213 | |
5260325f | 214 | signal(SIGCHLD, main_sigchld_handler); |
215 | errno = save_errno; | |
8efc0c15 | 216 | } |
217 | ||
5260325f | 218 | /* |
219 | * Signal handler for the alarm after the login grace period has expired. | |
220 | */ | |
221 | void | |
222 | grace_alarm_handler(int sig) | |
8efc0c15 | 223 | { |
5260325f | 224 | /* Close the connection. */ |
225 | packet_close(); | |
8efc0c15 | 226 | |
5260325f | 227 | /* Log error and exit. */ |
228 | fatal("Timeout before authentication for %s.", get_remote_ipaddr()); | |
229 | } | |
8efc0c15 | 230 | |
5260325f | 231 | /* |
232 | * convert ssh auth msg type into description | |
233 | */ | |
234 | char * | |
235 | get_authname(int type) | |
8efc0c15 | 236 | { |
5260325f | 237 | switch (type) { |
238 | case SSH_CMSG_AUTH_PASSWORD: | |
239 | return "password"; | |
240 | case SSH_CMSG_AUTH_RSA: | |
241 | return "rsa"; | |
242 | case SSH_CMSG_AUTH_RHOSTS_RSA: | |
243 | return "rhosts-rsa"; | |
244 | case SSH_CMSG_AUTH_RHOSTS: | |
245 | return "rhosts"; | |
246 | #ifdef KRB4 | |
247 | case SSH_CMSG_AUTH_KERBEROS: | |
248 | return "kerberos"; | |
249 | #endif | |
250 | #ifdef SKEY | |
251 | case SSH_CMSG_AUTH_TIS_RESPONSE: | |
252 | return "s/key"; | |
253 | #endif | |
254 | } | |
255 | fatal("get_authname: unknown auth %d: internal error", type); | |
256 | return NULL; | |
8efc0c15 | 257 | } |
258 | ||
5260325f | 259 | /* |
260 | * Signal handler for the key regeneration alarm. Note that this | |
261 | * alarm only occurs in the daemon waiting for connections, and it does not | |
262 | * do anything with the private key or random state before forking. | |
263 | * Thus there should be no concurrency control/asynchronous execution | |
264 | * problems. | |
265 | */ | |
266 | void | |
267 | key_regeneration_alarm(int sig) | |
268 | { | |
269 | int save_errno = errno; | |
270 | ||
271 | /* Check if we should generate a new key. */ | |
272 | if (key_used) { | |
273 | /* This should really be done in the background. */ | |
274 | log("Generating new %d bit RSA key.", options.server_key_bits); | |
275 | ||
276 | if (sensitive_data.private_key != NULL) | |
277 | RSA_free(sensitive_data.private_key); | |
278 | sensitive_data.private_key = RSA_new(); | |
279 | ||
280 | if (public_key != NULL) | |
281 | RSA_free(public_key); | |
282 | public_key = RSA_new(); | |
283 | ||
284 | rsa_generate_key(sensitive_data.private_key, public_key, | |
285 | options.server_key_bits); | |
286 | arc4random_stir(); | |
287 | key_used = 0; | |
288 | log("RSA key generation complete."); | |
289 | } | |
290 | /* Reschedule the alarm. */ | |
291 | signal(SIGALRM, key_regeneration_alarm); | |
292 | alarm(options.key_regeneration_time); | |
293 | errno = save_errno; | |
294 | } | |
8efc0c15 | 295 | |
5260325f | 296 | /* |
297 | * Main program for the daemon. | |
298 | */ | |
8efc0c15 | 299 | int |
300 | main(int ac, char **av) | |
301 | { | |
5260325f | 302 | extern char *optarg; |
303 | extern int optind; | |
48e671d5 | 304 | int opt, sock_in = 0, sock_out = 0, newsock, i, fdsetsz, pid, on = 1; |
305 | socklen_t fromlen; | |
5260325f | 306 | int remote_major, remote_minor; |
307 | int silentrsa = 0; | |
48e671d5 | 308 | fd_set *fdset; |
309 | struct sockaddr_storage from; | |
5260325f | 310 | char buf[100]; /* Must not be larger than remote_version. */ |
311 | char remote_version[100]; /* Must be at least as big as buf. */ | |
312 | const char *remote_ip; | |
313 | int remote_port; | |
314 | char *comment; | |
315 | FILE *f; | |
316 | struct linger linger; | |
48e671d5 | 317 | struct addrinfo *ai; |
318 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
319 | int listen_sock, maxfd; | |
5260325f | 320 | |
321 | /* Save argv[0]. */ | |
322 | saved_argv = av; | |
323 | if (strchr(av[0], '/')) | |
324 | av0 = strrchr(av[0], '/') + 1; | |
325 | else | |
326 | av0 = av[0]; | |
327 | ||
328 | /* Initialize configuration options to their default values. */ | |
329 | initialize_server_options(&options); | |
330 | ||
331 | /* Parse command-line arguments. */ | |
48e671d5 | 332 | while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:diqQ46")) != EOF) { |
5260325f | 333 | switch (opt) { |
48e671d5 | 334 | case '4': |
335 | IPv4or6 = AF_INET; | |
336 | break; | |
337 | case '6': | |
338 | IPv4or6 = AF_INET6; | |
339 | break; | |
5260325f | 340 | case 'f': |
341 | config_file_name = optarg; | |
342 | break; | |
343 | case 'd': | |
344 | debug_flag = 1; | |
345 | options.log_level = SYSLOG_LEVEL_DEBUG; | |
346 | break; | |
347 | case 'i': | |
348 | inetd_flag = 1; | |
349 | break; | |
350 | case 'Q': | |
351 | silentrsa = 1; | |
352 | break; | |
353 | case 'q': | |
354 | options.log_level = SYSLOG_LEVEL_QUIET; | |
355 | break; | |
356 | case 'b': | |
357 | options.server_key_bits = atoi(optarg); | |
358 | break; | |
359 | case 'p': | |
48e671d5 | 360 | options.ports_from_cmdline = 1; |
361 | if (options.num_ports >= MAX_PORTS) | |
362 | fatal("too many ports.\n"); | |
363 | options.ports[options.num_ports++] = atoi(optarg); | |
5260325f | 364 | break; |
365 | case 'g': | |
366 | options.login_grace_time = atoi(optarg); | |
367 | break; | |
368 | case 'k': | |
369 | options.key_regeneration_time = atoi(optarg); | |
370 | break; | |
371 | case 'h': | |
372 | options.host_key_file = optarg; | |
373 | break; | |
374 | case 'V': | |
375 | client_version_string = optarg; | |
376 | /* only makes sense with inetd_flag, i.e. no listen() */ | |
377 | inetd_flag = 1; | |
378 | break; | |
379 | case '?': | |
380 | default: | |
381 | fprintf(stderr, "sshd version %s\n", SSH_VERSION); | |
0a2ff95d | 382 | #ifdef RSAREF |
383 | fprintf(stderr, "Compiled with RSAref.\n"); | |
384 | #endif | |
5260325f | 385 | fprintf(stderr, "Usage: %s [options]\n", av0); |
386 | fprintf(stderr, "Options:\n"); | |
aa3378df | 387 | fprintf(stderr, " -f file Configuration file (default %s)\n", SERVER_CONFIG_FILE); |
5260325f | 388 | fprintf(stderr, " -d Debugging mode\n"); |
389 | fprintf(stderr, " -i Started from inetd\n"); | |
390 | fprintf(stderr, " -q Quiet (no logging)\n"); | |
391 | fprintf(stderr, " -p port Listen on the specified port (default: 22)\n"); | |
392 | fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n"); | |
393 | fprintf(stderr, " -g seconds Grace period for authentication (default: 300)\n"); | |
394 | fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n"); | |
395 | fprintf(stderr, " -h file File from which to read host key (default: %s)\n", | |
48e671d5 | 396 | HOST_KEY_FILE); |
397 | fprintf(stderr, " -4 Use IPv4 only\n"); | |
398 | fprintf(stderr, " -6 Use IPv6 only\n"); | |
5260325f | 399 | exit(1); |
400 | } | |
401 | } | |
402 | ||
48e671d5 | 403 | /* |
404 | * Force logging to stderr until we have loaded the private host | |
405 | * key (unless started from inetd) | |
406 | */ | |
407 | log_init(av0, | |
408 | options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level, | |
409 | options.log_facility == -1 ? SYSLOG_FACILITY_AUTH : options.log_facility, | |
410 | !inetd_flag); | |
411 | ||
5260325f | 412 | /* check if RSA support exists */ |
413 | if (rsa_alive() == 0) { | |
414 | if (silentrsa == 0) | |
415 | printf("sshd: no RSA support in libssl and libcrypto -- exiting. See ssl(8)\n"); | |
416 | log("no RSA support in libssl and libcrypto -- exiting. See ssl(8)"); | |
417 | exit(1); | |
418 | } | |
419 | /* Read server configuration options from the configuration file. */ | |
420 | read_server_config(&options, config_file_name); | |
421 | ||
422 | /* Fill in default values for those options not explicitly set. */ | |
423 | fill_default_server_options(&options); | |
424 | ||
425 | /* Check certain values for sanity. */ | |
426 | if (options.server_key_bits < 512 || | |
427 | options.server_key_bits > 32768) { | |
428 | fprintf(stderr, "Bad server key size.\n"); | |
429 | exit(1); | |
430 | } | |
5260325f | 431 | /* Check that there are no remaining arguments. */ |
432 | if (optind < ac) { | |
433 | fprintf(stderr, "Extra argument %s.\n", av[optind]); | |
434 | exit(1); | |
8efc0c15 | 435 | } |
5260325f | 436 | |
437 | debug("sshd version %.100s", SSH_VERSION); | |
438 | ||
439 | sensitive_data.host_key = RSA_new(); | |
440 | errno = 0; | |
441 | /* Load the host key. It must have empty passphrase. */ | |
442 | if (!load_private_key(options.host_key_file, "", | |
443 | sensitive_data.host_key, &comment)) { | |
444 | error("Could not load host key: %.200s: %.100s", | |
445 | options.host_key_file, strerror(errno)); | |
446 | exit(1); | |
447 | } | |
448 | xfree(comment); | |
449 | ||
450 | /* Initialize the log (it is reinitialized below in case we | |
451 | forked). */ | |
452 | if (debug_flag && !inetd_flag) | |
453 | log_stderr = 1; | |
454 | log_init(av0, options.log_level, options.log_facility, log_stderr); | |
455 | ||
456 | /* If not in debugging mode, and not started from inetd, | |
457 | disconnect from the controlling terminal, and fork. The | |
458 | original process exits. */ | |
459 | if (!debug_flag && !inetd_flag) { | |
8efc0c15 | 460 | #ifdef TIOCNOTTY |
5260325f | 461 | int fd; |
8efc0c15 | 462 | #endif /* TIOCNOTTY */ |
5260325f | 463 | if (daemon(0, 0) < 0) |
464 | fatal("daemon() failed: %.200s", strerror(errno)); | |
465 | ||
466 | /* Disconnect from the controlling tty. */ | |
8efc0c15 | 467 | #ifdef TIOCNOTTY |
5260325f | 468 | fd = open("/dev/tty", O_RDWR | O_NOCTTY); |
469 | if (fd >= 0) { | |
470 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
471 | close(fd); | |
472 | } | |
8efc0c15 | 473 | #endif /* TIOCNOTTY */ |
8efc0c15 | 474 | } |
5260325f | 475 | /* Reinitialize the log (because of the fork above). */ |
476 | log_init(av0, options.log_level, options.log_facility, log_stderr); | |
477 | ||
478 | /* Check that server and host key lengths differ sufficiently. | |
479 | This is necessary to make double encryption work with rsaref. | |
480 | Oh, I hate software patents. I dont know if this can go? Niels */ | |
481 | if (options.server_key_bits > | |
482 | BN_num_bits(sensitive_data.host_key->n) - SSH_KEY_BITS_RESERVED && | |
483 | options.server_key_bits < | |
484 | BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) { | |
485 | options.server_key_bits = | |
486 | BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED; | |
487 | debug("Forcing server key to %d bits to make it differ from host key.", | |
488 | options.server_key_bits); | |
8efc0c15 | 489 | } |
5260325f | 490 | /* Do not display messages to stdout in RSA code. */ |
491 | rsa_set_verbose(0); | |
492 | ||
493 | /* Initialize the random number generator. */ | |
494 | arc4random_stir(); | |
495 | ||
496 | /* Chdir to the root directory so that the current disk can be | |
497 | unmounted if desired. */ | |
498 | chdir("/"); | |
499 | ||
500 | /* Close connection cleanly after attack. */ | |
501 | cipher_attack_detected = packet_disconnect; | |
502 | ||
503 | /* Start listening for a socket, unless started from inetd. */ | |
504 | if (inetd_flag) { | |
505 | int s1, s2; | |
506 | s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */ | |
507 | s2 = dup(s1); | |
508 | sock_in = dup(0); | |
509 | sock_out = dup(1); | |
510 | /* We intentionally do not close the descriptors 0, 1, and 2 | |
511 | as our code for setting the descriptors won\'t work | |
512 | if ttyfd happens to be one of those. */ | |
513 | debug("inetd sockets after dupping: %d, %d", sock_in, sock_out); | |
514 | ||
515 | public_key = RSA_new(); | |
516 | sensitive_data.private_key = RSA_new(); | |
517 | ||
518 | log("Generating %d bit RSA key.", options.server_key_bits); | |
519 | rsa_generate_key(sensitive_data.private_key, public_key, | |
520 | options.server_key_bits); | |
521 | arc4random_stir(); | |
522 | log("RSA key generation complete."); | |
523 | } else { | |
48e671d5 | 524 | for (ai = options.listen_addrs; ai; ai = ai->ai_next) { |
525 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
526 | continue; | |
527 | if (num_listen_socks >= MAX_LISTEN_SOCKS) | |
528 | fatal("Too many listen sockets. " | |
529 | "Enlarge MAX_LISTEN_SOCKS"); | |
530 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, | |
531 | ntop, sizeof(ntop), strport, sizeof(strport), | |
532 | NI_NUMERICHOST|NI_NUMERICSERV) != 0) { | |
533 | error("getnameinfo failed"); | |
534 | continue; | |
535 | } | |
536 | /* Create socket for listening. */ | |
537 | listen_sock = socket(ai->ai_family, SOCK_STREAM, 0); | |
538 | if (listen_sock < 0) { | |
539 | /* kernel may not support ipv6 */ | |
540 | verbose("socket: %.100s", strerror(errno)); | |
541 | continue; | |
542 | } | |
543 | if (fcntl(listen_sock, F_SETFL, O_NONBLOCK) < 0) { | |
544 | error("listen_sock O_NONBLOCK: %s", strerror(errno)); | |
545 | close(listen_sock); | |
546 | continue; | |
547 | } | |
548 | /* | |
549 | * Set socket options. We try to make the port | |
550 | * reusable and have it close as fast as possible | |
551 | * without waiting in unnecessary wait states on | |
552 | * close. | |
553 | */ | |
554 | setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, | |
555 | (void *) &on, sizeof(on)); | |
556 | linger.l_onoff = 1; | |
557 | linger.l_linger = 5; | |
558 | setsockopt(listen_sock, SOL_SOCKET, SO_LINGER, | |
559 | (void *) &linger, sizeof(linger)); | |
560 | ||
561 | debug("Bind to port %s on %s.", strport, ntop); | |
562 | ||
563 | /* Bind the socket to the desired port. */ | |
564 | if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { | |
565 | error("Bind to port %s on %s failed: %.200s.", | |
566 | strport, ntop, strerror(errno)); | |
567 | close(listen_sock); | |
568 | continue; | |
569 | } | |
570 | listen_socks[num_listen_socks] = listen_sock; | |
571 | num_listen_socks++; | |
572 | ||
573 | /* Start listening on the port. */ | |
574 | log("Server listening on %s port %s.", ntop, strport); | |
575 | if (listen(listen_sock, 5) < 0) | |
576 | fatal("listen: %.100s", strerror(errno)); | |
577 | ||
5260325f | 578 | } |
48e671d5 | 579 | freeaddrinfo(options.listen_addrs); |
580 | ||
581 | if (!num_listen_socks) | |
582 | fatal("Cannot bind any address."); | |
583 | ||
5260325f | 584 | if (!debug_flag) { |
aa3378df | 585 | /* |
586 | * Record our pid in /etc/sshd_pid to make it easier | |
587 | * to kill the correct sshd. We don\'t want to do | |
588 | * this before the bind above because the bind will | |
589 | * fail if there already is a daemon, and this will | |
590 | * overwrite any old pid in the file. | |
591 | */ | |
5260325f | 592 | f = fopen(SSH_DAEMON_PID_FILE, "w"); |
593 | if (f) { | |
594 | fprintf(f, "%u\n", (unsigned int) getpid()); | |
595 | fclose(f); | |
596 | } | |
8efc0c15 | 597 | } |
8efc0c15 | 598 | |
5260325f | 599 | public_key = RSA_new(); |
600 | sensitive_data.private_key = RSA_new(); | |
601 | ||
602 | log("Generating %d bit RSA key.", options.server_key_bits); | |
603 | rsa_generate_key(sensitive_data.private_key, public_key, | |
604 | options.server_key_bits); | |
605 | arc4random_stir(); | |
606 | log("RSA key generation complete."); | |
607 | ||
608 | /* Schedule server key regeneration alarm. */ | |
609 | signal(SIGALRM, key_regeneration_alarm); | |
610 | alarm(options.key_regeneration_time); | |
611 | ||
612 | /* Arrange to restart on SIGHUP. The handler needs listen_sock. */ | |
613 | signal(SIGHUP, sighup_handler); | |
614 | signal(SIGTERM, sigterm_handler); | |
615 | signal(SIGQUIT, sigterm_handler); | |
616 | ||
617 | /* Arrange SIGCHLD to be caught. */ | |
618 | signal(SIGCHLD, main_sigchld_handler); | |
619 | ||
48e671d5 | 620 | /* setup fd set for listen */ |
621 | maxfd = 0; | |
622 | for (i = 0; i < num_listen_socks; i++) | |
623 | if (listen_socks[i] > maxfd) | |
624 | maxfd = listen_socks[i]; | |
625 | fdsetsz = howmany(maxfd, NFDBITS) * sizeof(fd_mask); | |
626 | fdset = (fd_set *)xmalloc(fdsetsz); | |
627 | ||
aa3378df | 628 | /* |
629 | * Stay listening for connections until the system crashes or | |
630 | * the daemon is killed with a signal. | |
631 | */ | |
5260325f | 632 | for (;;) { |
633 | if (received_sighup) | |
634 | sighup_restart(); | |
48e671d5 | 635 | /* Wait in select until there is a connection. */ |
636 | memset(fdset, 0, fdsetsz); | |
637 | for (i = 0; i < num_listen_socks; i++) | |
638 | FD_SET(listen_socks[i], fdset); | |
639 | if (select(maxfd + 1, fdset, NULL, NULL, NULL) < 0) { | |
640 | if (errno != EINTR) | |
641 | error("select: %.100s", strerror(errno)); | |
2d86a6cc | 642 | continue; |
48e671d5 | 643 | } |
644 | for (i = 0; i < num_listen_socks; i++) { | |
645 | if (!FD_ISSET(listen_socks[i], fdset)) | |
5260325f | 646 | continue; |
48e671d5 | 647 | fromlen = sizeof(from); |
648 | newsock = accept(listen_socks[i], (struct sockaddr *)&from, | |
649 | &fromlen); | |
650 | if (newsock < 0) { | |
651 | if (errno != EINTR && errno != EWOULDBLOCK) | |
652 | error("accept: %.100s", strerror(errno)); | |
653 | continue; | |
654 | } | |
655 | if (fcntl(newsock, F_SETFL, 0) < 0) { | |
656 | error("newsock del O_NONBLOCK: %s", strerror(errno)); | |
5260325f | 657 | continue; |
658 | } | |
aa3378df | 659 | /* |
660 | * Got connection. Fork a child to handle it, unless | |
661 | * we are in debugging mode. | |
662 | */ | |
5260325f | 663 | if (debug_flag) { |
aa3378df | 664 | /* |
665 | * In debugging mode. Close the listening | |
666 | * socket, and start processing the | |
667 | * connection without forking. | |
668 | */ | |
5260325f | 669 | debug("Server will not fork when running in debugging mode."); |
48e671d5 | 670 | close_listen_socks(); |
5260325f | 671 | sock_in = newsock; |
672 | sock_out = newsock; | |
673 | pid = getpid(); | |
674 | break; | |
675 | } else { | |
aa3378df | 676 | /* |
677 | * Normal production daemon. Fork, and have | |
678 | * the child process the connection. The | |
679 | * parent continues listening. | |
680 | */ | |
5260325f | 681 | if ((pid = fork()) == 0) { |
aa3378df | 682 | /* |
683 | * Child. Close the listening socket, and start using the | |
684 | * accepted socket. Reinitialize logging (since our pid has | |
685 | * changed). We break out of the loop to handle the connection. | |
686 | */ | |
48e671d5 | 687 | close_listen_socks(); |
5260325f | 688 | sock_in = newsock; |
689 | sock_out = newsock; | |
690 | log_init(av0, options.log_level, options.log_facility, log_stderr); | |
691 | break; | |
692 | } | |
693 | } | |
694 | ||
695 | /* Parent. Stay in the loop. */ | |
696 | if (pid < 0) | |
697 | error("fork: %.100s", strerror(errno)); | |
698 | else | |
699 | debug("Forked child %d.", pid); | |
700 | ||
701 | /* Mark that the key has been used (it was "given" to the child). */ | |
702 | key_used = 1; | |
703 | ||
704 | arc4random_stir(); | |
705 | ||
706 | /* Close the new socket (the child is now taking care of it). */ | |
707 | close(newsock); | |
48e671d5 | 708 | } /* for (i = 0; i < num_listen_socks; i++) */ |
709 | /* child process check (or debug mode) */ | |
710 | if (num_listen_socks < 0) | |
711 | break; | |
5260325f | 712 | } |
713 | } | |
8efc0c15 | 714 | |
5260325f | 715 | /* This is the child processing a new connection. */ |
716 | ||
aa3378df | 717 | /* |
718 | * Disable the key regeneration alarm. We will not regenerate the | |
719 | * key since we are no longer in a position to give it to anyone. We | |
720 | * will not restart on SIGHUP since it no longer makes sense. | |
721 | */ | |
5260325f | 722 | alarm(0); |
723 | signal(SIGALRM, SIG_DFL); | |
724 | signal(SIGHUP, SIG_DFL); | |
725 | signal(SIGTERM, SIG_DFL); | |
726 | signal(SIGQUIT, SIG_DFL); | |
727 | signal(SIGCHLD, SIG_DFL); | |
728 | ||
aa3378df | 729 | /* |
730 | * Set socket options for the connection. We want the socket to | |
731 | * close as fast as possible without waiting for anything. If the | |
732 | * connection is not a socket, these will do nothing. | |
733 | */ | |
734 | /* setsockopt(sock_in, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */ | |
5260325f | 735 | linger.l_onoff = 1; |
736 | linger.l_linger = 5; | |
737 | setsockopt(sock_in, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger)); | |
738 | ||
aa3378df | 739 | /* |
740 | * Register our connection. This turns encryption off because we do | |
741 | * not have a key. | |
742 | */ | |
5260325f | 743 | packet_set_connection(sock_in, sock_out); |
744 | ||
745 | remote_port = get_remote_port(); | |
746 | remote_ip = get_remote_ipaddr(); | |
747 | ||
748 | /* Check whether logins are denied from this host. */ | |
749 | #ifdef LIBWRAP | |
48e671d5 | 750 | /* XXX LIBWRAP noes not know about IPv6 */ |
5260325f | 751 | { |
752 | struct request_info req; | |
8efc0c15 | 753 | |
5260325f | 754 | request_init(&req, RQ_DAEMON, av0, RQ_FILE, sock_in, NULL); |
755 | fromhost(&req); | |
8efc0c15 | 756 | |
5260325f | 757 | if (!hosts_access(&req)) { |
758 | close(sock_in); | |
759 | close(sock_out); | |
760 | refuse(&req); | |
761 | } | |
48e671d5 | 762 | /*XXX IPv6 verbose("Connection from %.500s port %d", eval_client(&req), remote_port); */ |
8efc0c15 | 763 | } |
48e671d5 | 764 | #endif /* LIBWRAP */ |
5260325f | 765 | /* Log the connection. */ |
766 | verbose("Connection from %.500s port %d", remote_ip, remote_port); | |
8efc0c15 | 767 | |
aa3378df | 768 | /* |
769 | * We don\'t want to listen forever unless the other side | |
770 | * successfully authenticates itself. So we set up an alarm which is | |
771 | * cleared after successful authentication. A limit of zero | |
772 | * indicates no limit. Note that we don\'t set the alarm in debugging | |
773 | * mode; it is just annoying to have the server exit just when you | |
774 | * are about to discover the bug. | |
775 | */ | |
5260325f | 776 | signal(SIGALRM, grace_alarm_handler); |
777 | if (!debug_flag) | |
778 | alarm(options.login_grace_time); | |
779 | ||
780 | if (client_version_string != NULL) { | |
781 | /* we are exec'ed by sshd2, so skip exchange of protocol version */ | |
782 | strlcpy(buf, client_version_string, sizeof(buf)); | |
783 | } else { | |
784 | /* Send our protocol version identification. */ | |
785 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", | |
786 | PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION); | |
a408af76 | 787 | if (atomicio(write, sock_out, buf, strlen(buf)) != strlen(buf)) |
48e671d5 | 788 | fatal("Could not write ident string to %s.", remote_ip); |
5260325f | 789 | |
790 | /* Read other side\'s version identification. */ | |
791 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
792 | if (read(sock_in, &buf[i], 1) != 1) | |
48e671d5 | 793 | fatal("Did not receive ident string from %s.", remote_ip); |
5260325f | 794 | if (buf[i] == '\r') { |
795 | buf[i] = '\n'; | |
796 | buf[i + 1] = 0; | |
797 | break; | |
798 | } | |
799 | if (buf[i] == '\n') { | |
800 | /* buf[i] == '\n' */ | |
801 | buf[i + 1] = 0; | |
802 | break; | |
803 | } | |
804 | } | |
805 | buf[sizeof(buf) - 1] = 0; | |
8efc0c15 | 806 | } |
5260325f | 807 | |
aa3378df | 808 | /* |
809 | * Check that the versions match. In future this might accept | |
810 | * several versions and set appropriate flags to handle them. | |
811 | */ | |
5260325f | 812 | if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor, |
a408af76 | 813 | remote_version) != 3) { |
814 | char *s = "Protocol mismatch.\n"; | |
815 | ||
816 | (void) atomicio(write, sock_out, s, strlen(s)); | |
5260325f | 817 | close(sock_in); |
818 | close(sock_out); | |
819 | fatal("Bad protocol version identification '%.100s' from %s", | |
48e671d5 | 820 | buf, remote_ip); |
5260325f | 821 | } |
822 | debug("Client protocol version %d.%d; client software version %.100s", | |
823 | remote_major, remote_minor, remote_version); | |
824 | if (remote_major != PROTOCOL_MAJOR) { | |
a408af76 | 825 | char *s = "Protocol major versions differ.\n"; |
826 | ||
827 | (void) atomicio(write, sock_out, s, strlen(s)); | |
5260325f | 828 | close(sock_in); |
829 | close(sock_out); | |
830 | fatal("Protocol major versions differ for %s: %d vs. %d", | |
48e671d5 | 831 | remote_ip, PROTOCOL_MAJOR, remote_major); |
8efc0c15 | 832 | } |
5260325f | 833 | /* Check that the client has sufficiently high software version. */ |
834 | if (remote_major == 1 && remote_minor < 3) | |
835 | packet_disconnect("Your ssh version is too old and is no longer supported. Please install a newer version."); | |
836 | ||
837 | if (remote_major == 1 && remote_minor == 3) { | |
838 | enable_compat13(); | |
839 | if (strcmp(remote_version, "OpenSSH-1.1") != 0) { | |
840 | debug("Agent forwarding disabled, remote version is not compatible."); | |
841 | no_agent_forwarding_flag = 1; | |
842 | } | |
843 | } | |
aa3378df | 844 | /* |
845 | * Check that the connection comes from a privileged port. Rhosts- | |
846 | * and Rhosts-RSA-Authentication only make sense from priviledged | |
847 | * programs. Of course, if the intruder has root access on his local | |
848 | * machine, he can connect from any port. So do not use these | |
849 | * authentication methods from machines that you do not trust. | |
850 | */ | |
5260325f | 851 | if (remote_port >= IPPORT_RESERVED || |
852 | remote_port < IPPORT_RESERVED / 2) { | |
853 | options.rhosts_authentication = 0; | |
854 | options.rhosts_rsa_authentication = 0; | |
855 | } | |
48e671d5 | 856 | #ifdef KRB4 |
857 | if (!packet_connection_is_ipv4() && | |
858 | options.kerberos_authentication) { | |
859 | debug("Kerberos Authentication disabled, only available for IPv4."); | |
860 | options.kerberos_authentication = 0; | |
861 | } | |
862 | #endif /* KRB4 */ | |
863 | ||
5260325f | 864 | packet_set_nonblocking(); |
865 | ||
866 | /* Handle the connection. */ | |
867 | do_connection(); | |
8efc0c15 | 868 | |
869 | #ifdef KRB4 | |
5260325f | 870 | /* Cleanup user's ticket cache file. */ |
871 | if (options.kerberos_ticket_cleanup) | |
872 | (void) dest_tkt(); | |
8efc0c15 | 873 | #endif /* KRB4 */ |
874 | ||
5260325f | 875 | /* Cleanup user's local Xauthority file. */ |
876 | if (xauthfile) | |
877 | unlink(xauthfile); | |
8efc0c15 | 878 | |
5260325f | 879 | /* The connection has been terminated. */ |
880 | verbose("Closing connection to %.100s", remote_ip); | |
8efc0c15 | 881 | |
d94aa2ae | 882 | #ifdef USE_PAM |
a5c9cd31 | 883 | finish_pam(); |
d94aa2ae | 884 | #endif /* USE_PAM */ |
8efc0c15 | 885 | |
5260325f | 886 | packet_close(); |
887 | exit(0); | |
888 | } | |
8efc0c15 | 889 | |
5260325f | 890 | /* |
891 | * Process an incoming connection. Protocol version identifiers have already | |
892 | * been exchanged. This sends server key and performs the key exchange. | |
893 | * Server and host keys will no longer be needed after this functions. | |
894 | */ | |
e7c0f9d5 | 895 | void |
896 | do_connection() | |
8efc0c15 | 897 | { |
5260325f | 898 | int i, len; |
899 | BIGNUM *session_key_int; | |
900 | unsigned char session_key[SSH_SESSION_KEY_LENGTH]; | |
901 | unsigned char check_bytes[8]; | |
902 | char *user; | |
903 | unsigned int cipher_type, auth_mask, protocol_flags; | |
95f1eccc | 904 | int plen, slen, ulen; |
5260325f | 905 | u_int32_t rand = 0; |
906 | ||
aa3378df | 907 | /* |
908 | * Generate check bytes that the client must send back in the user | |
909 | * packet in order for it to be accepted; this is used to defy ip | |
910 | * spoofing attacks. Note that this only works against somebody | |
911 | * doing IP spoofing from a remote machine; any machine on the local | |
912 | * network can still see outgoing packets and catch the random | |
913 | * cookie. This only affects rhosts authentication, and this is one | |
914 | * of the reasons why it is inherently insecure. | |
915 | */ | |
5260325f | 916 | for (i = 0; i < 8; i++) { |
917 | if (i % 4 == 0) | |
918 | rand = arc4random(); | |
919 | check_bytes[i] = rand & 0xff; | |
920 | rand >>= 8; | |
921 | } | |
922 | ||
aa3378df | 923 | /* |
924 | * Send our public key. We include in the packet 64 bits of random | |
925 | * data that must be matched in the reply in order to prevent IP | |
926 | * spoofing. | |
927 | */ | |
5260325f | 928 | packet_start(SSH_SMSG_PUBLIC_KEY); |
929 | for (i = 0; i < 8; i++) | |
930 | packet_put_char(check_bytes[i]); | |
931 | ||
932 | /* Store our public server RSA key. */ | |
933 | packet_put_int(BN_num_bits(public_key->n)); | |
934 | packet_put_bignum(public_key->e); | |
935 | packet_put_bignum(public_key->n); | |
936 | ||
937 | /* Store our public host RSA key. */ | |
938 | packet_put_int(BN_num_bits(sensitive_data.host_key->n)); | |
939 | packet_put_bignum(sensitive_data.host_key->e); | |
940 | packet_put_bignum(sensitive_data.host_key->n); | |
941 | ||
942 | /* Put protocol flags. */ | |
943 | packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); | |
944 | ||
945 | /* Declare which ciphers we support. */ | |
946 | packet_put_int(cipher_mask()); | |
947 | ||
948 | /* Declare supported authentication types. */ | |
949 | auth_mask = 0; | |
950 | if (options.rhosts_authentication) | |
951 | auth_mask |= 1 << SSH_AUTH_RHOSTS; | |
952 | if (options.rhosts_rsa_authentication) | |
953 | auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; | |
954 | if (options.rsa_authentication) | |
955 | auth_mask |= 1 << SSH_AUTH_RSA; | |
8efc0c15 | 956 | #ifdef KRB4 |
5260325f | 957 | if (options.kerberos_authentication) |
958 | auth_mask |= 1 << SSH_AUTH_KERBEROS; | |
8efc0c15 | 959 | #endif |
960 | #ifdef AFS | |
5260325f | 961 | if (options.kerberos_tgt_passing) |
962 | auth_mask |= 1 << SSH_PASS_KERBEROS_TGT; | |
963 | if (options.afs_token_passing) | |
964 | auth_mask |= 1 << SSH_PASS_AFS_TOKEN; | |
8efc0c15 | 965 | #endif |
5260325f | 966 | #ifdef SKEY |
967 | if (options.skey_authentication == 1) | |
968 | auth_mask |= 1 << SSH_AUTH_TIS; | |
969 | #endif | |
970 | if (options.password_authentication) | |
971 | auth_mask |= 1 << SSH_AUTH_PASSWORD; | |
972 | packet_put_int(auth_mask); | |
973 | ||
974 | /* Send the packet and wait for it to be sent. */ | |
975 | packet_send(); | |
976 | packet_write_wait(); | |
977 | ||
978 | debug("Sent %d bit public key and %d bit host key.", | |
979 | BN_num_bits(public_key->n), BN_num_bits(sensitive_data.host_key->n)); | |
980 | ||
981 | /* Read clients reply (cipher type and session key). */ | |
982 | packet_read_expect(&plen, SSH_CMSG_SESSION_KEY); | |
983 | ||
2d86a6cc | 984 | /* Get cipher type and check whether we accept this. */ |
5260325f | 985 | cipher_type = packet_get_char(); |
986 | ||
2d86a6cc | 987 | if (!(cipher_mask() & (1 << cipher_type))) |
988 | packet_disconnect("Warning: client selects unsupported cipher."); | |
989 | ||
5260325f | 990 | /* Get check bytes from the packet. These must match those we |
991 | sent earlier with the public key packet. */ | |
992 | for (i = 0; i < 8; i++) | |
993 | if (check_bytes[i] != packet_get_char()) | |
994 | packet_disconnect("IP Spoofing check bytes do not match."); | |
995 | ||
996 | debug("Encryption type: %.200s", cipher_name(cipher_type)); | |
997 | ||
998 | /* Get the encrypted integer. */ | |
999 | session_key_int = BN_new(); | |
1000 | packet_get_bignum(session_key_int, &slen); | |
1001 | ||
5260325f | 1002 | protocol_flags = packet_get_int(); |
1003 | packet_set_protocol_flags(protocol_flags); | |
1004 | ||
1005 | packet_integrity_check(plen, 1 + 8 + slen + 4, SSH_CMSG_SESSION_KEY); | |
1006 | ||
aa3378df | 1007 | /* |
1008 | * Decrypt it using our private server key and private host key (key | |
1009 | * with larger modulus first). | |
1010 | */ | |
5260325f | 1011 | if (BN_cmp(sensitive_data.private_key->n, sensitive_data.host_key->n) > 0) { |
1012 | /* Private key has bigger modulus. */ | |
1013 | if (BN_num_bits(sensitive_data.private_key->n) < | |
1014 | BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) { | |
1015 | fatal("do_connection: %s: private_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", | |
1016 | get_remote_ipaddr(), | |
1017 | BN_num_bits(sensitive_data.private_key->n), | |
1018 | BN_num_bits(sensitive_data.host_key->n), | |
1019 | SSH_KEY_BITS_RESERVED); | |
1020 | } | |
1021 | rsa_private_decrypt(session_key_int, session_key_int, | |
1022 | sensitive_data.private_key); | |
1023 | rsa_private_decrypt(session_key_int, session_key_int, | |
1024 | sensitive_data.host_key); | |
1025 | } else { | |
1026 | /* Host key has bigger modulus (or they are equal). */ | |
1027 | if (BN_num_bits(sensitive_data.host_key->n) < | |
1028 | BN_num_bits(sensitive_data.private_key->n) + SSH_KEY_BITS_RESERVED) { | |
1029 | fatal("do_connection: %s: host_key %d < private_key %d + SSH_KEY_BITS_RESERVED %d", | |
1030 | get_remote_ipaddr(), | |
1031 | BN_num_bits(sensitive_data.host_key->n), | |
1032 | BN_num_bits(sensitive_data.private_key->n), | |
1033 | SSH_KEY_BITS_RESERVED); | |
1034 | } | |
1035 | rsa_private_decrypt(session_key_int, session_key_int, | |
1036 | sensitive_data.host_key); | |
1037 | rsa_private_decrypt(session_key_int, session_key_int, | |
1038 | sensitive_data.private_key); | |
1039 | } | |
1040 | ||
5260325f | 1041 | compute_session_id(session_id, check_bytes, |
1042 | sensitive_data.host_key->n, | |
1043 | sensitive_data.private_key->n); | |
1044 | ||
aa3378df | 1045 | /* |
1046 | * Extract session key from the decrypted integer. The key is in the | |
1047 | * least significant 256 bits of the integer; the first byte of the | |
1048 | * key is in the highest bits. | |
1049 | */ | |
5260325f | 1050 | BN_mask_bits(session_key_int, sizeof(session_key) * 8); |
1051 | len = BN_num_bytes(session_key_int); | |
1052 | if (len < 0 || len > sizeof(session_key)) | |
1053 | fatal("do_connection: bad len from %s: session_key_int %d > sizeof(session_key) %d", | |
1054 | get_remote_ipaddr(), | |
1055 | len, sizeof(session_key)); | |
1056 | memset(session_key, 0, sizeof(session_key)); | |
1057 | BN_bn2bin(session_key_int, session_key + sizeof(session_key) - len); | |
1058 | ||
1059 | /* Xor the first 16 bytes of the session key with the session id. */ | |
1060 | for (i = 0; i < 16; i++) | |
1061 | session_key[i] ^= session_id[i]; | |
1062 | ||
1063 | /* Destroy the decrypted integer. It is no longer needed. */ | |
1064 | BN_clear_free(session_key_int); | |
1065 | ||
1066 | /* Set the session key. From this on all communications will be encrypted. */ | |
1067 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); | |
1068 | ||
1069 | /* Destroy our copy of the session key. It is no longer needed. */ | |
1070 | memset(session_key, 0, sizeof(session_key)); | |
1071 | ||
1072 | debug("Received session key; encryption turned on."); | |
1073 | ||
1074 | /* Send an acknowledgement packet. Note that this packet is sent encrypted. */ | |
1075 | packet_start(SSH_SMSG_SUCCESS); | |
1076 | packet_send(); | |
1077 | packet_write_wait(); | |
1078 | ||
1079 | /* Get the name of the user that we wish to log in as. */ | |
1080 | packet_read_expect(&plen, SSH_CMSG_USER); | |
1081 | ||
1082 | /* Get the user name. */ | |
95f1eccc | 1083 | user = packet_get_string(&ulen); |
1084 | packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER); | |
5260325f | 1085 | |
1086 | /* Destroy the private and public keys. They will no longer be needed. */ | |
1087 | RSA_free(public_key); | |
1088 | RSA_free(sensitive_data.private_key); | |
1089 | RSA_free(sensitive_data.host_key); | |
8efc0c15 | 1090 | |
5260325f | 1091 | setproctitle("%s", user); |
1092 | /* Do the authentication. */ | |
1093 | do_authentication(user); | |
1094 | } | |
8efc0c15 | 1095 | |
5260325f | 1096 | /* |
1097 | * Check if the user is allowed to log in via ssh. If user is listed in | |
1098 | * DenyUsers or user's primary group is listed in DenyGroups, false will | |
1099 | * be returned. If AllowUsers isn't empty and user isn't listed there, or | |
1100 | * if AllowGroups isn't empty and user isn't listed there, false will be | |
1101 | * returned. Otherwise true is returned. | |
1102 | * XXX This function should also check if user has a valid shell | |
1103 | */ | |
8efc0c15 | 1104 | static int |
5260325f | 1105 | allowed_user(struct passwd * pw) |
8efc0c15 | 1106 | { |
5260325f | 1107 | struct group *grp; |
1108 | int i; | |
1109 | ||
1110 | /* Shouldn't be called if pw is NULL, but better safe than sorry... */ | |
1111 | if (!pw) | |
1112 | return 0; | |
1113 | ||
1114 | /* XXX Should check for valid login shell */ | |
1115 | ||
1116 | /* Return false if user is listed in DenyUsers */ | |
1117 | if (options.num_deny_users > 0) { | |
1118 | if (!pw->pw_name) | |
1119 | return 0; | |
1120 | for (i = 0; i < options.num_deny_users; i++) | |
1121 | if (match_pattern(pw->pw_name, options.deny_users[i])) | |
1122 | return 0; | |
1123 | } | |
aa3378df | 1124 | /* Return false if AllowUsers isn't empty and user isn't listed there */ |
5260325f | 1125 | if (options.num_allow_users > 0) { |
1126 | if (!pw->pw_name) | |
1127 | return 0; | |
1128 | for (i = 0; i < options.num_allow_users; i++) | |
1129 | if (match_pattern(pw->pw_name, options.allow_users[i])) | |
1130 | break; | |
1131 | /* i < options.num_allow_users iff we break for loop */ | |
1132 | if (i >= options.num_allow_users) | |
1133 | return 0; | |
1134 | } | |
1135 | /* Get the primary group name if we need it. Return false if it fails */ | |
1136 | if (options.num_deny_groups > 0 || options.num_allow_groups > 0) { | |
1137 | grp = getgrgid(pw->pw_gid); | |
1138 | if (!grp) | |
1139 | return 0; | |
1140 | ||
1141 | /* Return false if user's group is listed in DenyGroups */ | |
1142 | if (options.num_deny_groups > 0) { | |
1143 | if (!grp->gr_name) | |
1144 | return 0; | |
1145 | for (i = 0; i < options.num_deny_groups; i++) | |
1146 | if (match_pattern(grp->gr_name, options.deny_groups[i])) | |
1147 | return 0; | |
1148 | } | |
aa3378df | 1149 | /* |
1150 | * Return false if AllowGroups isn't empty and user's group | |
1151 | * isn't listed there | |
1152 | */ | |
5260325f | 1153 | if (options.num_allow_groups > 0) { |
1154 | if (!grp->gr_name) | |
1155 | return 0; | |
1156 | for (i = 0; i < options.num_allow_groups; i++) | |
1157 | if (match_pattern(grp->gr_name, options.allow_groups[i])) | |
1158 | break; | |
1159 | /* i < options.num_allow_groups iff we break for | |
1160 | loop */ | |
1161 | if (i >= options.num_allow_groups) | |
1162 | return 0; | |
1163 | } | |
1164 | } | |
1165 | /* We found no reason not to let this user try to log on... */ | |
1166 | return 1; | |
8efc0c15 | 1167 | } |
1168 | ||
5260325f | 1169 | /* |
1170 | * Performs authentication of an incoming connection. Session key has already | |
1171 | * been exchanged and encryption is enabled. User is the user name to log | |
1172 | * in as (received from the client). | |
1173 | */ | |
8efc0c15 | 1174 | void |
e7c0f9d5 | 1175 | do_authentication(char *user) |
8efc0c15 | 1176 | { |
5260325f | 1177 | struct passwd *pw, pwcopy; |
e7c0f9d5 | 1178 | |
8efc0c15 | 1179 | #ifdef AFS |
5260325f | 1180 | /* If machine has AFS, set process authentication group. */ |
1181 | if (k_hasafs()) { | |
1182 | k_setpag(); | |
1183 | k_unlog(); | |
1184 | } | |
8efc0c15 | 1185 | #endif /* AFS */ |
5260325f | 1186 | |
1187 | /* Verify that the user is a valid user. */ | |
1188 | pw = getpwnam(user); | |
1189 | if (!pw || !allowed_user(pw)) | |
1190 | do_fake_authloop(user); | |
1191 | ||
1192 | /* Take a copy of the returned structure. */ | |
1193 | memset(&pwcopy, 0, sizeof(pwcopy)); | |
1194 | pwcopy.pw_name = xstrdup(pw->pw_name); | |
1195 | pwcopy.pw_passwd = xstrdup(pw->pw_passwd); | |
1196 | pwcopy.pw_uid = pw->pw_uid; | |
1197 | pwcopy.pw_gid = pw->pw_gid; | |
1198 | pwcopy.pw_dir = xstrdup(pw->pw_dir); | |
1199 | pwcopy.pw_shell = xstrdup(pw->pw_shell); | |
1200 | pw = &pwcopy; | |
8efc0c15 | 1201 | |
d94aa2ae | 1202 | #ifdef USE_PAM |
a5c9cd31 | 1203 | start_pam(pw); |
5aecb327 | 1204 | #endif |
0183ea1c | 1205 | |
aa3378df | 1206 | /* |
1207 | * If we are not running as root, the user must have the same uid as | |
1208 | * the server. | |
1209 | */ | |
5260325f | 1210 | if (getuid() != 0 && pw->pw_uid != getuid()) |
1211 | packet_disconnect("Cannot change user when server not running as root."); | |
8efc0c15 | 1212 | |
5260325f | 1213 | debug("Attempting authentication for %.100s.", user); |
8efc0c15 | 1214 | |
5260325f | 1215 | /* If the user has no password, accept authentication immediately. */ |
1216 | if (options.password_authentication && | |
8efc0c15 | 1217 | #ifdef KRB4 |
5260325f | 1218 | (!options.kerberos_authentication || options.kerberos_or_local_passwd) && |
8efc0c15 | 1219 | #endif /* KRB4 */ |
d94aa2ae | 1220 | #ifdef USE_PAM |
a5c9cd31 | 1221 | auth_pam_password(pw, "")) { |
d94aa2ae | 1222 | #else /* USE_PAM */ |
5260325f | 1223 | auth_password(pw, "")) { |
d94aa2ae | 1224 | #endif /* USE_PAM */ |
5260325f | 1225 | /* Authentication with empty password succeeded. */ |
1226 | log("Login for user %s from %.100s, accepted without authentication.", | |
1227 | pw->pw_name, get_remote_ipaddr()); | |
1228 | } else { | |
1229 | /* Loop until the user has been authenticated or the | |
1230 | connection is closed, do_authloop() returns only if | |
1231 | authentication is successfull */ | |
1232 | do_authloop(pw); | |
1233 | } | |
1234 | ||
1235 | /* Check if the user is logging in as root and root logins are disallowed. */ | |
1236 | if (pw->pw_uid == 0 && !options.permit_root_login) { | |
1237 | if (forced_command) | |
1238 | log("Root login accepted for forced command."); | |
1239 | else | |
1240 | packet_disconnect("ROOT LOGIN REFUSED FROM %.200s", | |
1241 | get_canonical_hostname()); | |
1242 | } | |
1243 | /* The user has been authenticated and accepted. */ | |
1244 | packet_start(SSH_SMSG_SUCCESS); | |
1245 | packet_send(); | |
1246 | packet_write_wait(); | |
1247 | ||
1248 | /* Perform session preparation. */ | |
1249 | do_authenticated(pw); | |
e7c0f9d5 | 1250 | } |
8efc0c15 | 1251 | |
5260325f | 1252 | #define AUTH_FAIL_MAX 6 |
1253 | #define AUTH_FAIL_LOG (AUTH_FAIL_MAX/2) | |
1254 | #define AUTH_FAIL_MSG "Too many authentication failures for %.100s" | |
e7c0f9d5 | 1255 | |
5260325f | 1256 | /* |
1257 | * read packets and try to authenticate local user *pw. | |
1258 | * return if authentication is successfull | |
1259 | */ | |
e7c0f9d5 | 1260 | void |
5260325f | 1261 | do_authloop(struct passwd * pw) |
e7c0f9d5 | 1262 | { |
5260325f | 1263 | int attempt = 0; |
1264 | unsigned int bits; | |
1265 | BIGNUM *client_host_key_e, *client_host_key_n; | |
1266 | BIGNUM *n; | |
1267 | char *client_user = NULL, *password = NULL; | |
1268 | char user[1024]; | |
1269 | int plen, dlen, nlen, ulen, elen; | |
1270 | int type = 0; | |
1271 | void (*authlog) (const char *fmt,...) = verbose; | |
e7c0f9d5 | 1272 | |
5260325f | 1273 | /* Indicate that authentication is needed. */ |
1274 | packet_start(SSH_SMSG_FAILURE); | |
1275 | packet_send(); | |
1276 | packet_write_wait(); | |
e7c0f9d5 | 1277 | |
5260325f | 1278 | for (attempt = 1;; attempt++) { |
1279 | int authenticated = 0; | |
1280 | strlcpy(user, "", sizeof user); | |
e7c0f9d5 | 1281 | |
5260325f | 1282 | /* Get a packet from the client. */ |
1283 | type = packet_read(&plen); | |
1284 | ||
1285 | /* Process the packet. */ | |
1286 | switch (type) { | |
e7c0f9d5 | 1287 | #ifdef AFS |
5260325f | 1288 | case SSH_CMSG_HAVE_KERBEROS_TGT: |
1289 | if (!options.kerberos_tgt_passing) { | |
1290 | /* packet_get_all(); */ | |
1291 | verbose("Kerberos tgt passing disabled."); | |
1292 | break; | |
1293 | } else { | |
1294 | /* Accept Kerberos tgt. */ | |
1295 | char *tgt = packet_get_string(&dlen); | |
1296 | packet_integrity_check(plen, 4 + dlen, type); | |
1297 | if (!auth_kerberos_tgt(pw, tgt)) | |
1298 | verbose("Kerberos tgt REFUSED for %s", pw->pw_name); | |
1299 | xfree(tgt); | |
1300 | } | |
1301 | continue; | |
1302 | ||
1303 | case SSH_CMSG_HAVE_AFS_TOKEN: | |
1304 | if (!options.afs_token_passing || !k_hasafs()) { | |
1305 | /* packet_get_all(); */ | |
1306 | verbose("AFS token passing disabled."); | |
1307 | break; | |
1308 | } else { | |
1309 | /* Accept AFS token. */ | |
1310 | char *token_string = packet_get_string(&dlen); | |
1311 | packet_integrity_check(plen, 4 + dlen, type); | |
1312 | if (!auth_afs_token(pw, token_string)) | |
1313 | verbose("AFS token REFUSED for %s", pw->pw_name); | |
1314 | xfree(token_string); | |
1315 | } | |
1316 | continue; | |
8efc0c15 | 1317 | #endif /* AFS */ |
e7c0f9d5 | 1318 | #ifdef KRB4 |
5260325f | 1319 | case SSH_CMSG_AUTH_KERBEROS: |
1320 | if (!options.kerberos_authentication) { | |
1321 | /* packet_get_all(); */ | |
1322 | verbose("Kerberos authentication disabled."); | |
1323 | break; | |
1324 | } else { | |
1325 | /* Try Kerberos v4 authentication. */ | |
1326 | KTEXT_ST auth; | |
1327 | char *tkt_user = NULL; | |
1328 | char *kdata = packet_get_string((unsigned int *) &auth.length); | |
1329 | packet_integrity_check(plen, 4 + auth.length, type); | |
1330 | ||
1331 | if (auth.length < MAX_KTXT_LEN) | |
1332 | memcpy(auth.dat, kdata, auth.length); | |
1333 | xfree(kdata); | |
1334 | ||
1335 | authenticated = auth_krb4(pw->pw_name, &auth, &tkt_user); | |
1336 | ||
1337 | if (authenticated) { | |
1338 | snprintf(user, sizeof user, " tktuser %s", tkt_user); | |
1339 | xfree(tkt_user); | |
1340 | } | |
1341 | } | |
1342 | break; | |
e7c0f9d5 | 1343 | #endif /* KRB4 */ |
5260325f | 1344 | |
1345 | case SSH_CMSG_AUTH_RHOSTS: | |
1346 | if (!options.rhosts_authentication) { | |
1347 | verbose("Rhosts authentication disabled."); | |
1348 | break; | |
1349 | } | |
aa3378df | 1350 | /* |
1351 | * Get client user name. Note that we just have to | |
1352 | * trust the client; this is one reason why rhosts | |
1353 | * authentication is insecure. (Another is | |
1354 | * IP-spoofing on a local network.) | |
1355 | */ | |
5260325f | 1356 | client_user = packet_get_string(&ulen); |
1357 | packet_integrity_check(plen, 4 + ulen, type); | |
1358 | ||
1359 | /* Try to authenticate using /etc/hosts.equiv and | |
1360 | .rhosts. */ | |
1361 | authenticated = auth_rhosts(pw, client_user); | |
1362 | ||
1363 | snprintf(user, sizeof user, " ruser %s", client_user); | |
5260325f | 1364 | break; |
1365 | ||
1366 | case SSH_CMSG_AUTH_RHOSTS_RSA: | |
1367 | if (!options.rhosts_rsa_authentication) { | |
1368 | verbose("Rhosts with RSA authentication disabled."); | |
1369 | break; | |
1370 | } | |
aa3378df | 1371 | /* |
1372 | * Get client user name. Note that we just have to | |
1373 | * trust the client; root on the client machine can | |
1374 | * claim to be any user. | |
1375 | */ | |
5260325f | 1376 | client_user = packet_get_string(&ulen); |
1377 | ||
1378 | /* Get the client host key. */ | |
1379 | client_host_key_e = BN_new(); | |
1380 | client_host_key_n = BN_new(); | |
1381 | bits = packet_get_int(); | |
1382 | packet_get_bignum(client_host_key_e, &elen); | |
1383 | packet_get_bignum(client_host_key_n, &nlen); | |
1384 | ||
1385 | if (bits != BN_num_bits(client_host_key_n)) | |
1386 | error("Warning: keysize mismatch for client_host_key: " | |
1387 | "actual %d, announced %d", BN_num_bits(client_host_key_n), bits); | |
1388 | packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type); | |
1389 | ||
1390 | authenticated = auth_rhosts_rsa(pw, client_user, | |
1391 | client_host_key_e, client_host_key_n); | |
1392 | BN_clear_free(client_host_key_e); | |
1393 | BN_clear_free(client_host_key_n); | |
1394 | ||
1395 | snprintf(user, sizeof user, " ruser %s", client_user); | |
5260325f | 1396 | break; |
1397 | ||
1398 | case SSH_CMSG_AUTH_RSA: | |
1399 | if (!options.rsa_authentication) { | |
1400 | verbose("RSA authentication disabled."); | |
1401 | break; | |
1402 | } | |
1403 | /* RSA authentication requested. */ | |
1404 | n = BN_new(); | |
1405 | packet_get_bignum(n, &nlen); | |
1406 | packet_integrity_check(plen, nlen, type); | |
1407 | authenticated = auth_rsa(pw, n); | |
1408 | BN_clear_free(n); | |
1409 | break; | |
1410 | ||
1411 | case SSH_CMSG_AUTH_PASSWORD: | |
1412 | if (!options.password_authentication) { | |
1413 | verbose("Password authentication disabled."); | |
1414 | break; | |
1415 | } | |
aa3378df | 1416 | /* |
1417 | * Read user password. It is in plain text, but was | |
1418 | * transmitted over the encrypted channel so it is | |
1419 | * not visible to an outside observer. | |
1420 | */ | |
5260325f | 1421 | password = packet_get_string(&dlen); |
1422 | packet_integrity_check(plen, 4 + dlen, type); | |
1423 | ||
d94aa2ae | 1424 | #ifdef USE_PAM |
5260325f | 1425 | /* Do PAM auth with password */ |
a5c9cd31 | 1426 | authenticated = auth_pam_password(pw, password); |
d94aa2ae | 1427 | #else /* USE_PAM */ |
5260325f | 1428 | /* Try authentication with the password. */ |
1429 | authenticated = auth_password(pw, password); | |
d94aa2ae | 1430 | #endif /* USE_PAM */ |
5260325f | 1431 | memset(password, 0, strlen(password)); |
1432 | xfree(password); | |
1433 | break; | |
5260325f | 1434 | |
1435 | #ifdef SKEY | |
1436 | case SSH_CMSG_AUTH_TIS: | |
1437 | debug("rcvd SSH_CMSG_AUTH_TIS"); | |
1438 | if (options.skey_authentication == 1) { | |
1439 | char *skeyinfo = skey_keyinfo(pw->pw_name); | |
1440 | if (skeyinfo == NULL) { | |
1441 | debug("generating fake skeyinfo for %.100s.", pw->pw_name); | |
1442 | skeyinfo = skey_fake_keyinfo(pw->pw_name); | |
1443 | } | |
1444 | if (skeyinfo != NULL) { | |
aa3378df | 1445 | /* we send our s/key- in tis-challenge messages */ |
5260325f | 1446 | debug("sending challenge '%s'", skeyinfo); |
1447 | packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE); | |
1448 | packet_put_string(skeyinfo, strlen(skeyinfo)); | |
1449 | packet_send(); | |
1450 | packet_write_wait(); | |
1451 | continue; | |
1452 | } | |
1453 | } | |
1454 | break; | |
1455 | case SSH_CMSG_AUTH_TIS_RESPONSE: | |
1456 | debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE"); | |
1457 | if (options.skey_authentication == 1) { | |
1458 | char *response = packet_get_string(&dlen); | |
1459 | debug("skey response == '%s'", response); | |
1460 | packet_integrity_check(plen, 4 + dlen, type); | |
1461 | authenticated = (skey_haskey(pw->pw_name) == 0 && | |
1462 | skey_passcheck(pw->pw_name, response) != -1); | |
1463 | xfree(response); | |
1464 | } | |
1465 | break; | |
1466 | #else | |
1467 | case SSH_CMSG_AUTH_TIS: | |
1468 | /* TIS Authentication is unsupported */ | |
1469 | log("TIS authentication unsupported."); | |
1470 | break; | |
1471 | #endif | |
1472 | ||
1473 | default: | |
aa3378df | 1474 | /* |
1475 | * Any unknown messages will be ignored (and failure | |
1476 | * returned) during authentication. | |
1477 | */ | |
5260325f | 1478 | log("Unknown message during authentication: type %d", type); |
1479 | break; | |
1480 | } | |
1481 | ||
1482 | /* Raise logging level */ | |
1483 | if (authenticated || | |
1484 | attempt == AUTH_FAIL_LOG || | |
1485 | type == SSH_CMSG_AUTH_PASSWORD) | |
1486 | authlog = log; | |
1487 | ||
1488 | authlog("%s %s for %.200s from %.200s port %d%s", | |
1489 | authenticated ? "Accepted" : "Failed", | |
1490 | get_authname(type), | |
1491 | pw->pw_uid == 0 ? "ROOT" : pw->pw_name, | |
1492 | get_remote_ipaddr(), | |
1493 | get_remote_port(), | |
1494 | user); | |
8efc0c15 | 1495 | |
d465f2ca | 1496 | if (authenticated) { |
a5c9cd31 | 1497 | #ifdef USE_PAM |
1498 | if (!do_pam_account(pw->pw_name, client_user)) | |
1499 | { | |
1500 | if (client_user != NULL) | |
1501 | xfree(client_user); | |
5260325f | 1502 | |
a5c9cd31 | 1503 | do_fake_authloop(pw->pw_name); |
1504 | } | |
1505 | #endif /* USE_PAM */ | |
5260325f | 1506 | return; |
d465f2ca | 1507 | } |
5260325f | 1508 | |
a5c9cd31 | 1509 | if (client_user != NULL) |
1510 | xfree(client_user); | |
d465f2ca | 1511 | |
a5c9cd31 | 1512 | if (attempt > AUTH_FAIL_MAX) |
5260325f | 1513 | packet_disconnect(AUTH_FAIL_MSG, pw->pw_name); |
1514 | ||
1515 | /* Send a message indicating that the authentication attempt failed. */ | |
1516 | packet_start(SSH_SMSG_FAILURE); | |
1517 | packet_send(); | |
1518 | packet_write_wait(); | |
1519 | } | |
8efc0c15 | 1520 | } |
1521 | ||
5260325f | 1522 | /* |
1523 | * The user does not exist or access is denied, | |
1524 | * but fake indication that authentication is needed. | |
1525 | */ | |
e7c0f9d5 | 1526 | void |
1527 | do_fake_authloop(char *user) | |
0183ea1c | 1528 | { |
5260325f | 1529 | int attempt = 0; |
1530 | ||
1531 | log("Faking authloop for illegal user %.200s from %.200s port %d", | |
1532 | user, | |
1533 | get_remote_ipaddr(), | |
1534 | get_remote_port()); | |
1535 | ||
1536 | /* Indicate that authentication is needed. */ | |
1537 | packet_start(SSH_SMSG_FAILURE); | |
1538 | packet_send(); | |
1539 | packet_write_wait(); | |
1540 | ||
aa3378df | 1541 | /* |
1542 | * Keep reading packets, and always respond with a failure. This is | |
1543 | * to avoid disclosing whether such a user really exists. | |
1544 | */ | |
5260325f | 1545 | for (attempt = 1;; attempt++) { |
aa3378df | 1546 | /* Read a packet. This will not return if the client disconnects. */ |
5260325f | 1547 | int plen; |
a5c9cd31 | 1548 | #ifndef SKEY |
1549 | (void)packet_read(&plen); | |
1550 | #else /* SKEY */ | |
5260325f | 1551 | int type = packet_read(&plen); |
5260325f | 1552 | int dlen; |
1553 | char *password, *skeyinfo; | |
95f1eccc | 1554 | /* Try to send a fake s/key challenge. */ |
1555 | if (options.skey_authentication == 1 && | |
5260325f | 1556 | (skeyinfo = skey_fake_keyinfo(user)) != NULL) { |
95f1eccc | 1557 | if (type == SSH_CMSG_AUTH_TIS) { |
1558 | packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE); | |
1559 | packet_put_string(skeyinfo, strlen(skeyinfo)); | |
1560 | packet_send(); | |
1561 | packet_write_wait(); | |
1562 | continue; | |
1563 | } else if (type == SSH_CMSG_AUTH_PASSWORD && | |
1564 | options.password_authentication && | |
1565 | (password = packet_get_string(&dlen)) != NULL && | |
1566 | dlen == 5 && | |
1567 | strncasecmp(password, "s/key", 5) == 0 ) { | |
1568 | packet_send_debug(skeyinfo); | |
1569 | } | |
5260325f | 1570 | } |
e7c0f9d5 | 1571 | #endif |
5260325f | 1572 | if (attempt > AUTH_FAIL_MAX) |
1573 | packet_disconnect(AUTH_FAIL_MSG, user); | |
1574 | ||
aa3378df | 1575 | /* |
1576 | * Send failure. This should be indistinguishable from a | |
1577 | * failed authentication. | |
1578 | */ | |
5260325f | 1579 | packet_start(SSH_SMSG_FAILURE); |
1580 | packet_send(); | |
1581 | packet_write_wait(); | |
1582 | } | |
1583 | /* NOTREACHED */ | |
1584 | abort(); | |
0183ea1c | 1585 | } |
1586 | ||
e7c0f9d5 | 1587 | |
5260325f | 1588 | /* |
1589 | * Remove local Xauthority file. | |
1590 | */ | |
6a17f9c2 | 1591 | static void |
1592 | xauthfile_cleanup_proc(void *ignore) | |
1593 | { | |
5260325f | 1594 | debug("xauthfile_cleanup_proc called"); |
6a17f9c2 | 1595 | |
5260325f | 1596 | if (xauthfile != NULL) { |
1597 | unlink(xauthfile); | |
1598 | xfree(xauthfile); | |
1599 | xauthfile = NULL; | |
1600 | } | |
6a17f9c2 | 1601 | } |
1602 | ||
5260325f | 1603 | /* |
1604 | * Prepares for an interactive session. This is called after the user has | |
1605 | * been successfully authenticated. During this message exchange, pseudo | |
1606 | * terminals are allocated, X11, TCP/IP, and authentication agent forwardings | |
1607 | * are requested, etc. | |
1608 | */ | |
1609 | void | |
1610 | do_authenticated(struct passwd * pw) | |
8efc0c15 | 1611 | { |
5260325f | 1612 | int type; |
1613 | int compression_level = 0, enable_compression_after_reply = 0; | |
1614 | int have_pty = 0, ptyfd = -1, ttyfd = -1, xauthfd = -1; | |
1615 | int row, col, xpixel, ypixel, screen; | |
1616 | char ttyname[64]; | |
1617 | char *command, *term = NULL, *display = NULL, *proto = NULL, | |
1618 | *data = NULL; | |
1619 | struct group *grp; | |
1620 | gid_t tty_gid; | |
1621 | mode_t tty_mode; | |
1622 | int n_bytes; | |
1623 | ||
aa3378df | 1624 | /* |
1625 | * Cancel the alarm we set to limit the time taken for | |
1626 | * authentication. | |
1627 | */ | |
5260325f | 1628 | alarm(0); |
1629 | ||
aa3378df | 1630 | /* |
1631 | * Inform the channel mechanism that we are the server side and that | |
1632 | * the client may request to connect to any port at all. (The user | |
1633 | * could do it anyway, and we wouldn\'t know what is permitted except | |
1634 | * by the client telling us, so we can equally well trust the client | |
1635 | * not to request anything bogus.) | |
1636 | */ | |
5260325f | 1637 | channel_permit_all_opens(); |
1638 | ||
aa3378df | 1639 | /* |
1640 | * We stay in this loop until the client requests to execute a shell | |
1641 | * or a command. | |
1642 | */ | |
5260325f | 1643 | while (1) { |
1644 | int plen, dlen; | |
1645 | ||
1646 | /* Get a packet from the client. */ | |
1647 | type = packet_read(&plen); | |
1648 | ||
1649 | /* Process the packet. */ | |
1650 | switch (type) { | |
1651 | case SSH_CMSG_REQUEST_COMPRESSION: | |
1652 | packet_integrity_check(plen, 4, type); | |
1653 | compression_level = packet_get_int(); | |
1654 | if (compression_level < 1 || compression_level > 9) { | |
1655 | packet_send_debug("Received illegal compression level %d.", | |
1656 | compression_level); | |
1657 | goto fail; | |
1658 | } | |
1659 | /* Enable compression after we have responded with SUCCESS. */ | |
1660 | enable_compression_after_reply = 1; | |
1661 | break; | |
1662 | ||
1663 | case SSH_CMSG_REQUEST_PTY: | |
1664 | if (no_pty_flag) { | |
1665 | debug("Allocating a pty not permitted for this authentication."); | |
1666 | goto fail; | |
1667 | } | |
1668 | if (have_pty) | |
1669 | packet_disconnect("Protocol error: you already have a pty."); | |
1670 | ||
1671 | debug("Allocating pty."); | |
1672 | ||
1673 | /* Allocate a pty and open it. */ | |
a408af76 | 1674 | if (!pty_allocate(&ptyfd, &ttyfd, ttyname, |
1675 | sizeof(ttyname))) { | |
5260325f | 1676 | error("Failed to allocate pty."); |
1677 | goto fail; | |
1678 | } | |
1679 | /* Determine the group to make the owner of the tty. */ | |
1680 | grp = getgrnam("tty"); | |
1681 | if (grp) { | |
1682 | tty_gid = grp->gr_gid; | |
1683 | tty_mode = S_IRUSR | S_IWUSR | S_IWGRP; | |
1684 | } else { | |
1685 | tty_gid = pw->pw_gid; | |
1686 | tty_mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH; | |
1687 | } | |
1688 | ||
1689 | /* Change ownership of the tty. */ | |
1690 | if (chown(ttyname, pw->pw_uid, tty_gid) < 0) | |
1691 | fatal("chown(%.100s, %d, %d) failed: %.100s", | |
1692 | ttyname, pw->pw_uid, tty_gid, strerror(errno)); | |
1693 | if (chmod(ttyname, tty_mode) < 0) | |
1694 | fatal("chmod(%.100s, 0%o) failed: %.100s", | |
1695 | ttyname, tty_mode, strerror(errno)); | |
1696 | ||
1697 | /* Get TERM from the packet. Note that the value may be of arbitrary length. */ | |
1698 | term = packet_get_string(&dlen); | |
1699 | packet_integrity_check(dlen, strlen(term), type); | |
1700 | /* packet_integrity_check(plen, 4 + dlen + 4*4 + n_bytes, type); */ | |
1701 | /* Remaining bytes */ | |
1702 | n_bytes = plen - (4 + dlen + 4 * 4); | |
1703 | ||
1704 | if (strcmp(term, "") == 0) | |
1705 | term = NULL; | |
1706 | ||
1707 | /* Get window size from the packet. */ | |
1708 | row = packet_get_int(); | |
1709 | col = packet_get_int(); | |
1710 | xpixel = packet_get_int(); | |
1711 | ypixel = packet_get_int(); | |
1712 | pty_change_window_size(ptyfd, row, col, xpixel, ypixel); | |
1713 | ||
1714 | /* Get tty modes from the packet. */ | |
1715 | tty_parse_modes(ttyfd, &n_bytes); | |
1716 | packet_integrity_check(plen, 4 + dlen + 4 * 4 + n_bytes, type); | |
1717 | ||
1718 | /* Indicate that we now have a pty. */ | |
1719 | have_pty = 1; | |
8946db53 | 1720 | |
d94aa2ae | 1721 | #ifdef USE_PAM |
8946db53 | 1722 | /* do the pam_open_session since we have the pty */ |
a5c9cd31 | 1723 | do_pam_session(pw->pw_name, ttyname); |
d94aa2ae | 1724 | #endif /* USE_PAM */ |
8946db53 | 1725 | |
5260325f | 1726 | break; |
1727 | ||
1728 | case SSH_CMSG_X11_REQUEST_FORWARDING: | |
1729 | if (!options.x11_forwarding) { | |
1730 | packet_send_debug("X11 forwarding disabled in server configuration file."); | |
1731 | goto fail; | |
1732 | } | |
8efc0c15 | 1733 | #ifdef XAUTH_PATH |
5260325f | 1734 | if (no_x11_forwarding_flag) { |
1735 | packet_send_debug("X11 forwarding not permitted for this authentication."); | |
1736 | goto fail; | |
1737 | } | |
1738 | debug("Received request for X11 forwarding with auth spoofing."); | |
1739 | if (display) | |
1740 | packet_disconnect("Protocol error: X11 display already set."); | |
1741 | { | |
1742 | int proto_len, data_len; | |
1743 | proto = packet_get_string(&proto_len); | |
1744 | data = packet_get_string(&data_len); | |
1745 | packet_integrity_check(plen, 4 + proto_len + 4 + data_len + 4, type); | |
1746 | } | |
1747 | if (packet_get_protocol_flags() & SSH_PROTOFLAG_SCREEN_NUMBER) | |
1748 | screen = packet_get_int(); | |
1749 | else | |
1750 | screen = 0; | |
95f1eccc | 1751 | display = x11_create_display_inet(screen, options.x11_display_offset); |
5260325f | 1752 | if (!display) |
1753 | goto fail; | |
1754 | ||
1755 | /* Setup to always have a local .Xauthority. */ | |
1756 | xauthfile = xmalloc(MAXPATHLEN); | |
1757 | snprintf(xauthfile, MAXPATHLEN, "/tmp/XauthXXXXXX"); | |
1758 | ||
1759 | if ((xauthfd = mkstemp(xauthfile)) != -1) { | |
1760 | fchown(xauthfd, pw->pw_uid, pw->pw_gid); | |
1761 | close(xauthfd); | |
1762 | fatal_add_cleanup(xauthfile_cleanup_proc, NULL); | |
1763 | } else { | |
1764 | xfree(xauthfile); | |
1765 | xauthfile = NULL; | |
1766 | } | |
1767 | break; | |
8efc0c15 | 1768 | #else /* XAUTH_PATH */ |
5260325f | 1769 | packet_send_debug("No xauth program; cannot forward with spoofing."); |
1770 | goto fail; | |
8efc0c15 | 1771 | #endif /* XAUTH_PATH */ |
1772 | ||
5260325f | 1773 | case SSH_CMSG_AGENT_REQUEST_FORWARDING: |
1774 | if (no_agent_forwarding_flag) { | |
1775 | debug("Authentication agent forwarding not permitted for this authentication."); | |
1776 | goto fail; | |
1777 | } | |
1778 | debug("Received authentication agent forwarding request."); | |
1779 | auth_input_request_forwarding(pw); | |
1780 | break; | |
1781 | ||
1782 | case SSH_CMSG_PORT_FORWARD_REQUEST: | |
1783 | if (no_port_forwarding_flag) { | |
1784 | debug("Port forwarding not permitted for this authentication."); | |
1785 | goto fail; | |
1786 | } | |
1787 | debug("Received TCP/IP port forwarding request."); | |
1788 | channel_input_port_forward_request(pw->pw_uid == 0); | |
1789 | break; | |
1790 | ||
1791 | case SSH_CMSG_MAX_PACKET_SIZE: | |
1792 | if (packet_set_maxsize(packet_get_int()) < 0) | |
1793 | goto fail; | |
1794 | break; | |
1795 | ||
1796 | case SSH_CMSG_EXEC_SHELL: | |
1797 | /* Set interactive/non-interactive mode. */ | |
1798 | packet_set_interactive(have_pty || display != NULL, | |
1799 | options.keepalives); | |
1800 | ||
f91bacbd | 1801 | #ifdef USE_PAM |
1802 | do_pam_setcred(); | |
a5c9cd31 | 1803 | #endif /* USE_PAM */ |
5260325f | 1804 | if (forced_command != NULL) |
1805 | goto do_forced_command; | |
1806 | debug("Forking shell."); | |
1807 | packet_integrity_check(plen, 0, type); | |
1808 | if (have_pty) | |
1809 | do_exec_pty(NULL, ptyfd, ttyfd, ttyname, pw, term, display, proto, data); | |
1810 | else | |
1811 | do_exec_no_pty(NULL, pw, display, proto, data); | |
1812 | return; | |
1813 | ||
1814 | case SSH_CMSG_EXEC_CMD: | |
1815 | /* Set interactive/non-interactive mode. */ | |
1816 | packet_set_interactive(have_pty || display != NULL, | |
1817 | options.keepalives); | |
1818 | ||
f91bacbd | 1819 | #ifdef USE_PAM |
1820 | do_pam_setcred(); | |
a5c9cd31 | 1821 | #endif /* USE_PAM */ |
5260325f | 1822 | if (forced_command != NULL) |
1823 | goto do_forced_command; | |
1824 | /* Get command from the packet. */ | |
1825 | { | |
1826 | int dlen; | |
1827 | command = packet_get_string(&dlen); | |
1828 | debug("Executing command '%.500s'", command); | |
1829 | packet_integrity_check(plen, 4 + dlen, type); | |
1830 | } | |
1831 | if (have_pty) | |
1832 | do_exec_pty(command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data); | |
1833 | else | |
1834 | do_exec_no_pty(command, pw, display, proto, data); | |
1835 | xfree(command); | |
1836 | return; | |
1837 | ||
1838 | default: | |
aa3378df | 1839 | /* |
1840 | * Any unknown messages in this phase are ignored, | |
1841 | * and a failure message is returned. | |
1842 | */ | |
5260325f | 1843 | log("Unknown packet type received after authentication: %d", type); |
1844 | goto fail; | |
1845 | } | |
8efc0c15 | 1846 | |
5260325f | 1847 | /* The request was successfully processed. */ |
1848 | packet_start(SSH_SMSG_SUCCESS); | |
1849 | packet_send(); | |
1850 | packet_write_wait(); | |
8efc0c15 | 1851 | |
5260325f | 1852 | /* Enable compression now that we have replied if appropriate. */ |
1853 | if (enable_compression_after_reply) { | |
1854 | enable_compression_after_reply = 0; | |
1855 | packet_start_compression(compression_level); | |
1856 | } | |
1857 | continue; | |
8efc0c15 | 1858 | |
5260325f | 1859 | fail: |
1860 | /* The request failed. */ | |
1861 | packet_start(SSH_SMSG_FAILURE); | |
1862 | packet_send(); | |
1863 | packet_write_wait(); | |
1864 | continue; | |
8efc0c15 | 1865 | |
5260325f | 1866 | do_forced_command: |
aa3378df | 1867 | /* |
1868 | * There is a forced command specified for this login. | |
1869 | * Execute it. | |
1870 | */ | |
5260325f | 1871 | debug("Executing forced command: %.900s", forced_command); |
1872 | if (have_pty) | |
1873 | do_exec_pty(forced_command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data); | |
1874 | else | |
1875 | do_exec_no_pty(forced_command, pw, display, proto, data); | |
1876 | return; | |
1877 | } | |
1878 | } | |
8efc0c15 | 1879 | |
5260325f | 1880 | /* |
1881 | * This is called to fork and execute a command when we have no tty. This | |
1882 | * will call do_child from the child, and server_loop from the parent after | |
1883 | * setting up file descriptors and such. | |
1884 | */ | |
1885 | void | |
1886 | do_exec_no_pty(const char *command, struct passwd * pw, | |
1887 | const char *display, const char *auth_proto, | |
1888 | const char *auth_data) | |
1889 | { | |
1890 | int pid; | |
8efc0c15 | 1891 | |
1892 | #ifdef USE_PIPES | |
5260325f | 1893 | int pin[2], pout[2], perr[2]; |
1894 | /* Allocate pipes for communicating with the program. */ | |
1895 | if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0) | |
1896 | packet_disconnect("Could not create pipes: %.100s", | |
1897 | strerror(errno)); | |
8efc0c15 | 1898 | #else /* USE_PIPES */ |
5260325f | 1899 | int inout[2], err[2]; |
1900 | /* Uses socket pairs to communicate with the program. */ | |
1901 | if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 || | |
1902 | socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) | |
1903 | packet_disconnect("Could not create socket pairs: %.100s", | |
1904 | strerror(errno)); | |
8efc0c15 | 1905 | #endif /* USE_PIPES */ |
8efc0c15 | 1906 | |
5260325f | 1907 | setproctitle("%s@notty", pw->pw_name); |
8efc0c15 | 1908 | |
5260325f | 1909 | /* Fork the child. */ |
1910 | if ((pid = fork()) == 0) { | |
1911 | /* Child. Reinitialize the log since the pid has changed. */ | |
1912 | log_init(av0, options.log_level, options.log_facility, log_stderr); | |
1913 | ||
aa3378df | 1914 | /* |
1915 | * Create a new session and process group since the 4.4BSD | |
1916 | * setlogin() affects the entire process group. | |
1917 | */ | |
5260325f | 1918 | if (setsid() < 0) |
1919 | error("setsid failed: %.100s", strerror(errno)); | |
8efc0c15 | 1920 | |
1921 | #ifdef USE_PIPES | |
aa3378df | 1922 | /* |
1923 | * Redirect stdin. We close the parent side of the socket | |
1924 | * pair, and make the child side the standard input. | |
1925 | */ | |
5260325f | 1926 | close(pin[1]); |
1927 | if (dup2(pin[0], 0) < 0) | |
1928 | perror("dup2 stdin"); | |
1929 | close(pin[0]); | |
1930 | ||
1931 | /* Redirect stdout. */ | |
1932 | close(pout[0]); | |
1933 | if (dup2(pout[1], 1) < 0) | |
1934 | perror("dup2 stdout"); | |
1935 | close(pout[1]); | |
1936 | ||
1937 | /* Redirect stderr. */ | |
1938 | close(perr[0]); | |
1939 | if (dup2(perr[1], 2) < 0) | |
1940 | perror("dup2 stderr"); | |
1941 | close(perr[1]); | |
8efc0c15 | 1942 | #else /* USE_PIPES */ |
aa3378df | 1943 | /* |
1944 | * Redirect stdin, stdout, and stderr. Stdin and stdout will | |
1945 | * use the same socket, as some programs (particularly rdist) | |
1946 | * seem to depend on it. | |
1947 | */ | |
5260325f | 1948 | close(inout[1]); |
1949 | close(err[1]); | |
1950 | if (dup2(inout[0], 0) < 0) /* stdin */ | |
1951 | perror("dup2 stdin"); | |
1952 | if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */ | |
1953 | perror("dup2 stdout"); | |
1954 | if (dup2(err[0], 2) < 0) /* stderr */ | |
1955 | perror("dup2 stderr"); | |
8efc0c15 | 1956 | #endif /* USE_PIPES */ |
1957 | ||
5260325f | 1958 | /* Do processing for the child (exec command etc). */ |
1959 | do_child(command, pw, NULL, display, auth_proto, auth_data, NULL); | |
1960 | /* NOTREACHED */ | |
1961 | } | |
1962 | if (pid < 0) | |
1963 | packet_disconnect("fork failed: %.100s", strerror(errno)); | |
8efc0c15 | 1964 | #ifdef USE_PIPES |
5260325f | 1965 | /* We are the parent. Close the child sides of the pipes. */ |
1966 | close(pin[0]); | |
1967 | close(pout[1]); | |
1968 | close(perr[1]); | |
1969 | ||
1970 | /* Enter the interactive session. */ | |
1971 | server_loop(pid, pin[1], pout[0], perr[0]); | |
1972 | /* server_loop has closed pin[1], pout[1], and perr[1]. */ | |
8efc0c15 | 1973 | #else /* USE_PIPES */ |
5260325f | 1974 | /* We are the parent. Close the child sides of the socket pairs. */ |
1975 | close(inout[0]); | |
1976 | close(err[0]); | |
1977 | ||
aa3378df | 1978 | /* |
1979 | * Enter the interactive session. Note: server_loop must be able to | |
1980 | * handle the case that fdin and fdout are the same. | |
1981 | */ | |
5260325f | 1982 | server_loop(pid, inout[1], inout[1], err[1]); |
1983 | /* server_loop has closed inout[1] and err[1]. */ | |
8efc0c15 | 1984 | #endif /* USE_PIPES */ |
1985 | } | |
1986 | ||
5260325f | 1987 | struct pty_cleanup_context { |
1988 | const char *ttyname; | |
1989 | int pid; | |
8efc0c15 | 1990 | }; |
1991 | ||
5260325f | 1992 | /* |
1993 | * Function to perform cleanup if we get aborted abnormally (e.g., due to a | |
1994 | * dropped connection). | |
1995 | */ | |
1996 | void | |
1997 | pty_cleanup_proc(void *context) | |
8efc0c15 | 1998 | { |
5260325f | 1999 | struct pty_cleanup_context *cu = context; |
8efc0c15 | 2000 | |
5260325f | 2001 | debug("pty_cleanup_proc called"); |
8efc0c15 | 2002 | |
5260325f | 2003 | /* Record that the user has logged out. */ |
2004 | record_logout(cu->pid, cu->ttyname); | |
8efc0c15 | 2005 | |
5260325f | 2006 | /* Release the pseudo-tty. */ |
2007 | pty_release(cu->ttyname); | |
8efc0c15 | 2008 | } |
2009 | ||
5260325f | 2010 | /* |
2011 | * This is called to fork and execute a command when we have a tty. This | |
2012 | * will call do_child from the child, and server_loop from the parent after | |
2013 | * setting up file descriptors, controlling tty, updating wtmp, utmp, | |
2014 | * lastlog, and other such operations. | |
2015 | */ | |
2016 | void | |
2017 | do_exec_pty(const char *command, int ptyfd, int ttyfd, | |
2018 | const char *ttyname, struct passwd * pw, const char *term, | |
2019 | const char *display, const char *auth_proto, | |
2020 | const char *auth_data) | |
8efc0c15 | 2021 | { |
5260325f | 2022 | int pid, fdout; |
2023 | const char *hostname; | |
2024 | time_t last_login_time; | |
2025 | char buf[100], *time_string; | |
2026 | FILE *f; | |
2027 | char line[256]; | |
2028 | struct stat st; | |
2029 | int quiet_login; | |
48e671d5 | 2030 | struct sockaddr_storage from; |
2031 | socklen_t fromlen; | |
5260325f | 2032 | struct pty_cleanup_context cleanup_context; |
2033 | ||
2034 | /* Get remote host name. */ | |
2035 | hostname = get_canonical_hostname(); | |
2036 | ||
aa3378df | 2037 | /* |
2038 | * Get the time when the user last logged in. Buf will be set to | |
2039 | * contain the hostname the last login was from. | |
2040 | */ | |
5260325f | 2041 | if (!options.use_login) { |
2042 | last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name, | |
2043 | buf, sizeof(buf)); | |
8efc0c15 | 2044 | } |
5260325f | 2045 | setproctitle("%s@%s", pw->pw_name, strrchr(ttyname, '/') + 1); |
2046 | ||
2047 | /* Fork the child. */ | |
2048 | if ((pid = fork()) == 0) { | |
2049 | pid = getpid(); | |
2050 | ||
2051 | /* Child. Reinitialize the log because the pid has | |
2052 | changed. */ | |
2053 | log_init(av0, options.log_level, options.log_facility, log_stderr); | |
2054 | ||
2055 | /* Close the master side of the pseudo tty. */ | |
2056 | close(ptyfd); | |
2057 | ||
2058 | /* Make the pseudo tty our controlling tty. */ | |
2059 | pty_make_controlling_tty(&ttyfd, ttyname); | |
2060 | ||
2061 | /* Redirect stdin from the pseudo tty. */ | |
2062 | if (dup2(ttyfd, fileno(stdin)) < 0) | |
2063 | error("dup2 stdin failed: %.100s", strerror(errno)); | |
2064 | ||
2065 | /* Redirect stdout to the pseudo tty. */ | |
2066 | if (dup2(ttyfd, fileno(stdout)) < 0) | |
2067 | error("dup2 stdin failed: %.100s", strerror(errno)); | |
2068 | ||
2069 | /* Redirect stderr to the pseudo tty. */ | |
2070 | if (dup2(ttyfd, fileno(stderr)) < 0) | |
2071 | error("dup2 stdin failed: %.100s", strerror(errno)); | |
2072 | ||
2073 | /* Close the extra descriptor for the pseudo tty. */ | |
2074 | close(ttyfd); | |
2075 | ||
aa3378df | 2076 | /* |
2077 | * Get IP address of client. This is needed because we want | |
2078 | * to record where the user logged in from. If the | |
2079 | * connection is not a socket, let the ip address be 0.0.0.0. | |
2080 | */ | |
5260325f | 2081 | memset(&from, 0, sizeof(from)); |
2082 | if (packet_get_connection_in() == packet_get_connection_out()) { | |
2083 | fromlen = sizeof(from); | |
2084 | if (getpeername(packet_get_connection_in(), | |
2085 | (struct sockaddr *) & from, &fromlen) < 0) { | |
2086 | debug("getpeername: %.100s", strerror(errno)); | |
2087 | fatal_cleanup(); | |
2088 | } | |
2089 | } | |
2090 | /* Record that there was a login on that terminal. */ | |
2091 | record_login(pid, ttyname, pw->pw_name, pw->pw_uid, hostname, | |
48e671d5 | 2092 | (struct sockaddr *)&from); |
8efc0c15 | 2093 | |
5260325f | 2094 | /* Check if .hushlogin exists. */ |
2095 | snprintf(line, sizeof line, "%.200s/.hushlogin", pw->pw_dir); | |
2096 | quiet_login = stat(line, &st) >= 0; | |
e1a9c08d | 2097 | |
d94aa2ae | 2098 | #ifdef USE_PAM |
a5c9cd31 | 2099 | if (!quiet_login) |
2100 | print_pam_messages(); | |
2101 | #endif /* USE_PAM */ | |
8efc0c15 | 2102 | |
aa3378df | 2103 | /* |
2104 | * If the user has logged in before, display the time of last | |
2105 | * login. However, don't display anything extra if a command | |
2106 | * has been specified (so that ssh can be used to execute | |
2107 | * commands on a remote machine without users knowing they | |
2108 | * are going to another machine). Login(1) will do this for | |
2109 | * us as well, so check if login(1) is used | |
2110 | */ | |
5260325f | 2111 | if (command == NULL && last_login_time != 0 && !quiet_login && |
2112 | !options.use_login) { | |
2113 | /* Convert the date to a string. */ | |
2114 | time_string = ctime(&last_login_time); | |
2115 | /* Remove the trailing newline. */ | |
2116 | if (strchr(time_string, '\n')) | |
2117 | *strchr(time_string, '\n') = 0; | |
2118 | /* Display the last login time. Host if displayed | |
2119 | if known. */ | |
2120 | if (strcmp(buf, "") == 0) | |
2121 | printf("Last login: %s\r\n", time_string); | |
2122 | else | |
2123 | printf("Last login: %s from %s\r\n", time_string, buf); | |
2124 | } | |
aa3378df | 2125 | /* |
2126 | * Print /etc/motd unless a command was specified or printing | |
2127 | * it was disabled in server options or login(1) will be | |
2128 | * used. Note that some machines appear to print it in | |
2129 | * /etc/profile or similar. | |
2130 | */ | |
5260325f | 2131 | if (command == NULL && options.print_motd && !quiet_login && |
2132 | !options.use_login) { | |
2133 | /* Print /etc/motd if it exists. */ | |
2134 | f = fopen("/etc/motd", "r"); | |
2135 | if (f) { | |
2136 | while (fgets(line, sizeof(line), f)) | |
2137 | fputs(line, stdout); | |
2138 | fclose(f); | |
2139 | } | |
2140 | } | |
2141 | /* Do common processing for the child, such as execing the command. */ | |
2142 | do_child(command, pw, term, display, auth_proto, auth_data, ttyname); | |
2143 | /* NOTREACHED */ | |
8efc0c15 | 2144 | } |
5260325f | 2145 | if (pid < 0) |
2146 | packet_disconnect("fork failed: %.100s", strerror(errno)); | |
2147 | /* Parent. Close the slave side of the pseudo tty. */ | |
2148 | close(ttyfd); | |
2149 | ||
aa3378df | 2150 | /* |
2151 | * Create another descriptor of the pty master side for use as the | |
2152 | * standard input. We could use the original descriptor, but this | |
2153 | * simplifies code in server_loop. The descriptor is bidirectional. | |
2154 | */ | |
5260325f | 2155 | fdout = dup(ptyfd); |
2156 | if (fdout < 0) | |
2157 | packet_disconnect("dup failed: %.100s", strerror(errno)); | |
2158 | ||
aa3378df | 2159 | /* |
2160 | * Add a cleanup function to clear the utmp entry and record logout | |
2161 | * time in case we call fatal() (e.g., the connection gets closed). | |
2162 | */ | |
5260325f | 2163 | cleanup_context.pid = pid; |
2164 | cleanup_context.ttyname = ttyname; | |
2165 | fatal_add_cleanup(pty_cleanup_proc, (void *) &cleanup_context); | |
2166 | ||
2167 | /* Enter interactive session. */ | |
2168 | server_loop(pid, ptyfd, fdout, -1); | |
2169 | /* server_loop has not closed ptyfd and fdout. */ | |
2170 | ||
2171 | /* Cancel the cleanup function. */ | |
2172 | fatal_remove_cleanup(pty_cleanup_proc, (void *) &cleanup_context); | |
2173 | ||
2174 | /* Record that the user has logged out. */ | |
2175 | record_logout(pid, ttyname); | |
2176 | ||
2177 | /* Release the pseudo-tty. */ | |
2178 | pty_release(ttyname); | |
2179 | ||
aa3378df | 2180 | /* |
2181 | * Close the server side of the socket pairs. We must do this after | |
2182 | * the pty cleanup, so that another process doesn't get this pty | |
2183 | * while we're still cleaning up. | |
2184 | */ | |
5260325f | 2185 | close(ptyfd); |
2186 | close(fdout); | |
8efc0c15 | 2187 | } |
2188 | ||
5260325f | 2189 | /* |
2190 | * Sets the value of the given variable in the environment. If the variable | |
2191 | * already exists, its value is overriden. | |
2192 | */ | |
2193 | void | |
2194 | child_set_env(char ***envp, unsigned int *envsizep, const char *name, | |
2195 | const char *value) | |
8efc0c15 | 2196 | { |
5260325f | 2197 | unsigned int i, namelen; |
2198 | char **env; | |
2199 | ||
aa3378df | 2200 | /* |
2201 | * Find the slot where the value should be stored. If the variable | |
2202 | * already exists, we reuse the slot; otherwise we append a new slot | |
2203 | * at the end of the array, expanding if necessary. | |
2204 | */ | |
5260325f | 2205 | env = *envp; |
2206 | namelen = strlen(name); | |
2207 | for (i = 0; env[i]; i++) | |
2208 | if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=') | |
2209 | break; | |
2210 | if (env[i]) { | |
aa3378df | 2211 | /* Reuse the slot. */ |
5260325f | 2212 | xfree(env[i]); |
2213 | } else { | |
aa3378df | 2214 | /* New variable. Expand if necessary. */ |
5260325f | 2215 | if (i >= (*envsizep) - 1) { |
2216 | (*envsizep) += 50; | |
2217 | env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *)); | |
2218 | } | |
2219 | /* Need to set the NULL pointer at end of array beyond the new slot. */ | |
2220 | env[i + 1] = NULL; | |
8efc0c15 | 2221 | } |
2222 | ||
5260325f | 2223 | /* Allocate space and format the variable in the appropriate slot. */ |
2224 | env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1); | |
2225 | snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value); | |
8efc0c15 | 2226 | } |
2227 | ||
5260325f | 2228 | /* |
2229 | * Reads environment variables from the given file and adds/overrides them | |
2230 | * into the environment. If the file does not exist, this does nothing. | |
2231 | * Otherwise, it must consist of empty lines, comments (line starts with '#') | |
2232 | * and assignments of the form name=value. No other forms are allowed. | |
2233 | */ | |
2234 | void | |
2235 | read_environment_file(char ***env, unsigned int *envsize, | |
2236 | const char *filename) | |
8efc0c15 | 2237 | { |
5260325f | 2238 | FILE *f; |
2239 | char buf[4096]; | |
2240 | char *cp, *value; | |
2241 | ||
5260325f | 2242 | f = fopen(filename, "r"); |
2243 | if (!f) | |
2244 | return; | |
2245 | ||
5260325f | 2246 | while (fgets(buf, sizeof(buf), f)) { |
aa3378df | 2247 | for (cp = buf; *cp == ' ' || *cp == '\t'; cp++) |
2248 | ; | |
5260325f | 2249 | if (!*cp || *cp == '#' || *cp == '\n') |
2250 | continue; | |
5260325f | 2251 | if (strchr(cp, '\n')) |
2252 | *strchr(cp, '\n') = '\0'; | |
5260325f | 2253 | value = strchr(cp, '='); |
2254 | if (value == NULL) { | |
2255 | fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf); | |
2256 | continue; | |
2257 | } | |
aa3378df | 2258 | /* Replace the equals sign by nul, and advance value to the value string. */ |
5260325f | 2259 | *value = '\0'; |
2260 | value++; | |
5260325f | 2261 | child_set_env(env, envsize, cp, value); |
2262 | } | |
5260325f | 2263 | fclose(f); |
8efc0c15 | 2264 | } |
2265 | ||
a5c9cd31 | 2266 | #ifdef USE_PAM |
2267 | /* | |
2268 | * Sets any environment variables which have been specified by PAM | |
2269 | */ | |
2270 | void do_pam_environment(char ***env, int *envsize) | |
2271 | { | |
2272 | char *equals, var_name[512], var_val[512]; | |
2273 | char **pam_env; | |
2274 | int i; | |
2275 | ||
2276 | if ((pam_env = fetch_pam_environment()) == NULL) | |
2277 | return; | |
2278 | ||
2279 | for(i = 0; pam_env[i] != NULL; i++) { | |
2280 | if ((equals = strstr(pam_env[i], "=")) == NULL) | |
2281 | continue; | |
2282 | ||
2283 | if (strlen(pam_env[i]) < (sizeof(var_name) - 1)) | |
2284 | { | |
2285 | memset(var_name, '\0', sizeof(var_name)); | |
2286 | memset(var_val, '\0', sizeof(var_val)); | |
2287 | ||
2288 | strncpy(var_name, pam_env[i], equals - pam_env[i]); | |
2289 | strcpy(var_val, equals + 1); | |
2290 | ||
2291 | debug("PAM environment: %s=%s", var_name, var_val); | |
2292 | ||
2293 | child_set_env(env, envsize, var_name, var_val); | |
2294 | } | |
2295 | } | |
2296 | } | |
2297 | #endif /* USE_PAM */ | |
2298 | ||
5260325f | 2299 | /* |
2300 | * Performs common processing for the child, such as setting up the | |
2301 | * environment, closing extra file descriptors, setting the user and group | |
2302 | * ids, and executing the command or shell. | |
2303 | */ | |
2304 | void | |
2305 | do_child(const char *command, struct passwd * pw, const char *term, | |
2306 | const char *display, const char *auth_proto, | |
2307 | const char *auth_data, const char *ttyname) | |
8efc0c15 | 2308 | { |
5260325f | 2309 | const char *shell, *cp = NULL; |
2310 | char buf[256]; | |
2311 | FILE *f; | |
2312 | unsigned int envsize, i; | |
2313 | char **env; | |
2314 | extern char **environ; | |
2315 | struct stat st; | |
2316 | char *argv[10]; | |
8efc0c15 | 2317 | |
d94aa2ae | 2318 | #ifndef USE_PAM /* pam_nologin handles this */ |
5260325f | 2319 | /* Check /etc/nologin. */ |
2320 | f = fopen("/etc/nologin", "r"); | |
2321 | if (f) { | |
2322 | /* /etc/nologin exists. Print its contents and exit. */ | |
2323 | while (fgets(buf, sizeof(buf), f)) | |
2324 | fputs(buf, stderr); | |
2325 | fclose(f); | |
2326 | if (pw->pw_uid != 0) | |
2327 | exit(254); | |
2328 | } | |
d94aa2ae | 2329 | #endif /* USE_PAM */ |
e35c1dc2 | 2330 | |
5260325f | 2331 | /* Set login name in the kernel. */ |
2332 | if (setlogin(pw->pw_name) < 0) | |
2333 | error("setlogin failed: %s", strerror(errno)); | |
8efc0c15 | 2334 | |
5260325f | 2335 | /* Set uid, gid, and groups. */ |
2336 | /* Login(1) does this as well, and it needs uid 0 for the "-h" | |
2337 | switch, so we let login(1) to this for us. */ | |
2338 | if (!options.use_login) { | |
2339 | if (getuid() == 0 || geteuid() == 0) { | |
2340 | if (setgid(pw->pw_gid) < 0) { | |
2341 | perror("setgid"); | |
2342 | exit(1); | |
2343 | } | |
2344 | /* Initialize the group list. */ | |
2345 | if (initgroups(pw->pw_name, pw->pw_gid) < 0) { | |
2346 | perror("initgroups"); | |
2347 | exit(1); | |
2348 | } | |
2349 | endgrent(); | |
2350 | ||
2351 | /* Permanently switch to the desired uid. */ | |
2352 | permanently_set_uid(pw->pw_uid); | |
2353 | } | |
2354 | if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid) | |
2355 | fatal("Failed to set uids to %d.", (int) pw->pw_uid); | |
2356 | } | |
aa3378df | 2357 | /* |
2358 | * Get the shell from the password data. An empty shell field is | |
2359 | * legal, and means /bin/sh. | |
2360 | */ | |
5260325f | 2361 | shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell; |
8efc0c15 | 2362 | |
2363 | #ifdef AFS | |
5260325f | 2364 | /* Try to get AFS tokens for the local cell. */ |
2365 | if (k_hasafs()) { | |
2366 | char cell[64]; | |
2367 | ||
2368 | if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0) | |
2369 | krb_afslog(cell, 0); | |
2370 | ||
2371 | krb_afslog(0, 0); | |
2372 | } | |
8efc0c15 | 2373 | #endif /* AFS */ |
5260325f | 2374 | |
aa3378df | 2375 | /* Initialize the environment. */ |
5260325f | 2376 | envsize = 100; |
2377 | env = xmalloc(envsize * sizeof(char *)); | |
2378 | env[0] = NULL; | |
2379 | ||
2380 | if (!options.use_login) { | |
2381 | /* Set basic environment. */ | |
2382 | child_set_env(&env, &envsize, "USER", pw->pw_name); | |
2383 | child_set_env(&env, &envsize, "LOGNAME", pw->pw_name); | |
2384 | child_set_env(&env, &envsize, "HOME", pw->pw_dir); | |
2385 | child_set_env(&env, &envsize, "PATH", _PATH_STDPATH); | |
2386 | ||
2387 | snprintf(buf, sizeof buf, "%.200s/%.50s", | |
2388 | _PATH_MAILDIR, pw->pw_name); | |
2389 | child_set_env(&env, &envsize, "MAIL", buf); | |
2390 | ||
2391 | /* Normal systems set SHELL by default. */ | |
2392 | child_set_env(&env, &envsize, "SHELL", shell); | |
2393 | } | |
5260325f | 2394 | if (getenv("TZ")) |
2395 | child_set_env(&env, &envsize, "TZ", getenv("TZ")); | |
2396 | ||
2397 | /* Set custom environment options from RSA authentication. */ | |
2398 | while (custom_environment) { | |
2399 | struct envstring *ce = custom_environment; | |
2400 | char *s = ce->s; | |
2401 | int i; | |
2402 | for (i = 0; s[i] != '=' && s[i]; i++); | |
2403 | if (s[i] == '=') { | |
2404 | s[i] = 0; | |
2405 | child_set_env(&env, &envsize, s, s + i + 1); | |
2406 | } | |
2407 | custom_environment = ce->next; | |
2408 | xfree(ce->s); | |
2409 | xfree(ce); | |
8efc0c15 | 2410 | } |
8efc0c15 | 2411 | |
5260325f | 2412 | snprintf(buf, sizeof buf, "%.50s %d %d", |
48e671d5 | 2413 | get_remote_ipaddr(), get_remote_port(), get_local_port()); |
5260325f | 2414 | child_set_env(&env, &envsize, "SSH_CLIENT", buf); |
8efc0c15 | 2415 | |
5260325f | 2416 | if (ttyname) |
2417 | child_set_env(&env, &envsize, "SSH_TTY", ttyname); | |
5260325f | 2418 | if (term) |
2419 | child_set_env(&env, &envsize, "TERM", term); | |
5260325f | 2420 | if (display) |
2421 | child_set_env(&env, &envsize, "DISPLAY", display); | |
8efc0c15 | 2422 | |
2423 | #ifdef KRB4 | |
5260325f | 2424 | { |
2425 | extern char *ticket; | |
2426 | ||
2427 | if (ticket) | |
2428 | child_set_env(&env, &envsize, "KRBTKFILE", ticket); | |
2429 | } | |
8efc0c15 | 2430 | #endif /* KRB4 */ |
2431 | ||
d94aa2ae | 2432 | #ifdef USE_PAM |
5260325f | 2433 | /* Pull in any environment variables that may have been set by PAM. */ |
a5c9cd31 | 2434 | do_pam_environment(&env, &envsize); |
d94aa2ae | 2435 | #endif /* USE_PAM */ |
bb0dd7f6 | 2436 | |
5260325f | 2437 | if (xauthfile) |
2438 | child_set_env(&env, &envsize, "XAUTHORITY", xauthfile); | |
2439 | ||
5260325f | 2440 | if (auth_get_socket_name() != NULL) |
2441 | child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME, | |
2442 | auth_get_socket_name()); | |
2443 | ||
aa3378df | 2444 | /* read $HOME/.ssh/environment. */ |
5260325f | 2445 | if (!options.use_login) { |
2446 | snprintf(buf, sizeof buf, "%.200s/.ssh/environment", pw->pw_dir); | |
2447 | read_environment_file(&env, &envsize, buf); | |
2448 | } | |
5260325f | 2449 | if (debug_flag) { |
aa3378df | 2450 | /* dump the environment */ |
5260325f | 2451 | fprintf(stderr, "Environment:\n"); |
2452 | for (i = 0; env[i]; i++) | |
2453 | fprintf(stderr, " %.200s\n", env[i]); | |
2454 | } | |
aa3378df | 2455 | /* |
2456 | * Close the connection descriptors; note that this is the child, and | |
2457 | * the server will still have the socket open, and it is important | |
2458 | * that we do not shutdown it. Note that the descriptors cannot be | |
2459 | * closed before building the environment, as we call | |
2460 | * get_remote_ipaddr there. | |
2461 | */ | |
5260325f | 2462 | if (packet_get_connection_in() == packet_get_connection_out()) |
2463 | close(packet_get_connection_in()); | |
2464 | else { | |
2465 | close(packet_get_connection_in()); | |
2466 | close(packet_get_connection_out()); | |
2467 | } | |
aa3378df | 2468 | /* |
2469 | * Close all descriptors related to channels. They will still remain | |
2470 | * open in the parent. | |
2471 | */ | |
2472 | /* XXX better use close-on-exec? -markus */ | |
5260325f | 2473 | channel_close_all(); |
2474 | ||
aa3378df | 2475 | /* |
2476 | * Close any extra file descriptors. Note that there may still be | |
2477 | * descriptors left by system functions. They will be closed later. | |
2478 | */ | |
5260325f | 2479 | endpwent(); |
5260325f | 2480 | |
aa3378df | 2481 | /* |
2482 | * Close any extra open file descriptors so that we don\'t have them | |
2483 | * hanging around in clients. Note that we want to do this after | |
2484 | * initgroups, because at least on Solaris 2.3 it leaves file | |
2485 | * descriptors open. | |
2486 | */ | |
5260325f | 2487 | for (i = 3; i < 64; i++) |
2488 | close(i); | |
2489 | ||
2490 | /* Change current directory to the user\'s home directory. */ | |
2491 | if (chdir(pw->pw_dir) < 0) | |
2492 | fprintf(stderr, "Could not chdir to home directory %s: %s\n", | |
2493 | pw->pw_dir, strerror(errno)); | |
2494 | ||
aa3378df | 2495 | /* |
2496 | * Must take new environment into use so that .ssh/rc, /etc/sshrc and | |
2497 | * xauth are run in the proper environment. | |
2498 | */ | |
5260325f | 2499 | environ = env; |
2500 | ||
aa3378df | 2501 | /* |
2502 | * Run $HOME/.ssh/rc, /etc/sshrc, or xauth (whichever is found first | |
2503 | * in this order). | |
2504 | */ | |
5260325f | 2505 | if (!options.use_login) { |
2506 | if (stat(SSH_USER_RC, &st) >= 0) { | |
2507 | if (debug_flag) | |
2508 | fprintf(stderr, "Running /bin/sh %s\n", SSH_USER_RC); | |
2509 | ||
2510 | f = popen("/bin/sh " SSH_USER_RC, "w"); | |
2511 | if (f) { | |
2512 | if (auth_proto != NULL && auth_data != NULL) | |
2513 | fprintf(f, "%s %s\n", auth_proto, auth_data); | |
2514 | pclose(f); | |
2515 | } else | |
2516 | fprintf(stderr, "Could not run %s\n", SSH_USER_RC); | |
2517 | } else if (stat(SSH_SYSTEM_RC, &st) >= 0) { | |
2518 | if (debug_flag) | |
2519 | fprintf(stderr, "Running /bin/sh %s\n", SSH_SYSTEM_RC); | |
2520 | ||
2521 | f = popen("/bin/sh " SSH_SYSTEM_RC, "w"); | |
2522 | if (f) { | |
2523 | if (auth_proto != NULL && auth_data != NULL) | |
2524 | fprintf(f, "%s %s\n", auth_proto, auth_data); | |
2525 | pclose(f); | |
2526 | } else | |
2527 | fprintf(stderr, "Could not run %s\n", SSH_SYSTEM_RC); | |
2528 | } | |
8efc0c15 | 2529 | #ifdef XAUTH_PATH |
5260325f | 2530 | else { |
aa3378df | 2531 | /* Add authority data to .Xauthority if appropriate. */ |
5260325f | 2532 | if (auth_proto != NULL && auth_data != NULL) { |
2533 | if (debug_flag) | |
2534 | fprintf(stderr, "Running %.100s add %.100s %.100s %.100s\n", | |
2535 | XAUTH_PATH, display, auth_proto, auth_data); | |
2536 | ||
2537 | f = popen(XAUTH_PATH " -q -", "w"); | |
2538 | if (f) { | |
2539 | fprintf(f, "add %s %s %s\n", display, auth_proto, auth_data); | |
2540 | fclose(f); | |
2541 | } else | |
2542 | fprintf(stderr, "Could not run %s -q -\n", XAUTH_PATH); | |
2543 | } | |
2544 | } | |
8efc0c15 | 2545 | #endif /* XAUTH_PATH */ |
2546 | ||
5260325f | 2547 | /* Get the last component of the shell name. */ |
2548 | cp = strrchr(shell, '/'); | |
2549 | if (cp) | |
2550 | cp++; | |
2551 | else | |
2552 | cp = shell; | |
2553 | } | |
aa3378df | 2554 | /* |
2555 | * If we have no command, execute the shell. In this case, the shell | |
2556 | * name to be passed in argv[0] is preceded by '-' to indicate that | |
2557 | * this is a login shell. | |
2558 | */ | |
5260325f | 2559 | if (!command) { |
2560 | if (!options.use_login) { | |
2561 | char buf[256]; | |
2562 | ||
aa3378df | 2563 | /* |
2564 | * Check for mail if we have a tty and it was enabled | |
2565 | * in server options. | |
2566 | */ | |
5260325f | 2567 | if (ttyname && options.check_mail) { |
2568 | char *mailbox; | |
2569 | struct stat mailstat; | |
2570 | mailbox = getenv("MAIL"); | |
2571 | if (mailbox != NULL) { | |
2572 | if (stat(mailbox, &mailstat) != 0 || mailstat.st_size == 0) | |
2573 | printf("No mail.\n"); | |
2574 | else if (mailstat.st_mtime < mailstat.st_atime) | |
2575 | printf("You have mail.\n"); | |
2576 | else | |
2577 | printf("You have new mail.\n"); | |
2578 | } | |
2579 | } | |
2580 | /* Start the shell. Set initial character to '-'. */ | |
2581 | buf[0] = '-'; | |
2582 | strncpy(buf + 1, cp, sizeof(buf) - 1); | |
2583 | buf[sizeof(buf) - 1] = 0; | |
2584 | ||
2585 | /* Execute the shell. */ | |
2586 | argv[0] = buf; | |
2587 | argv[1] = NULL; | |
2588 | execve(shell, argv, env); | |
2589 | ||
2590 | /* Executing the shell failed. */ | |
2591 | perror(shell); | |
2592 | exit(1); | |
2593 | ||
2594 | } else { | |
2595 | /* Launch login(1). */ | |
2596 | ||
2597 | execl(LOGIN_PROGRAM, "login", "-h", get_remote_ipaddr(), | |
2598 | "-p", "-f", "--", pw->pw_name, NULL); | |
2599 | ||
2600 | /* Login couldn't be executed, die. */ | |
2601 | ||
2602 | perror("login"); | |
2603 | exit(1); | |
2604 | } | |
2605 | } | |
aa3378df | 2606 | /* |
2607 | * Execute the command using the user's shell. This uses the -c | |
2608 | * option to execute the command. | |
2609 | */ | |
5260325f | 2610 | argv[0] = (char *) cp; |
2611 | argv[1] = "-c"; | |
2612 | argv[2] = (char *) command; | |
2613 | argv[3] = NULL; | |
2614 | execve(shell, argv, env); | |
2615 | perror(shell); | |
2616 | exit(1); | |
8efc0c15 | 2617 | } |