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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 | ||
5260325f | 48 | /* |
49 | * Debug mode flag. This can be set on the command line. If debug | |
50 | * mode is enabled, extra debugging output will be sent to the system | |
51 | * log, the daemon will not go to background, and will exit after processing | |
52 | * the first connection. | |
53 | */ | |
8efc0c15 | 54 | int debug_flag = 0; |
55 | ||
56 | /* Flag indicating that the daemon is being started from inetd. */ | |
57 | int inetd_flag = 0; | |
58 | ||
6a17f9c2 | 59 | /* debug goes to stderr unless inetd_flag is set */ |
60 | int log_stderr = 0; | |
61 | ||
8efc0c15 | 62 | /* argv[0] without path. */ |
63 | char *av0; | |
64 | ||
65 | /* Saved arguments to main(). */ | |
66 | char **saved_argv; | |
67 | ||
aa3378df | 68 | /* |
69 | * This is set to the socket that the server is listening; this is used in | |
70 | * the SIGHUP signal handler. | |
71 | */ | |
8efc0c15 | 72 | int listen_sock; |
73 | ||
aa3378df | 74 | /* |
75 | * the client's version string, passed by sshd2 in compat mode. if != NULL, | |
76 | * sshd will skip the version-number exchange | |
77 | */ | |
5260325f | 78 | char *client_version_string = NULL; |
79 | ||
80 | /* Flags set in auth-rsa from authorized_keys flags. These are set in auth-rsa.c. */ | |
8efc0c15 | 81 | int no_port_forwarding_flag = 0; |
82 | int no_agent_forwarding_flag = 0; | |
83 | int no_x11_forwarding_flag = 0; | |
84 | int no_pty_flag = 0; | |
5260325f | 85 | |
86 | /* RSA authentication "command=" option. */ | |
87 | char *forced_command = NULL; | |
88 | ||
89 | /* RSA authentication "environment=" options. */ | |
90 | struct envstring *custom_environment = NULL; | |
8efc0c15 | 91 | |
92 | /* Session id for the current session. */ | |
93 | unsigned char session_id[16]; | |
94 | ||
aa3378df | 95 | /* |
96 | * Any really sensitive data in the application is contained in this | |
97 | * structure. The idea is that this structure could be locked into memory so | |
98 | * that the pages do not get written into swap. However, there are some | |
99 | * problems. The private key contains BIGNUMs, and we do not (in principle) | |
100 | * have access to the internals of them, and locking just the structure is | |
101 | * not very useful. Currently, memory locking is not implemented. | |
102 | */ | |
5260325f | 103 | struct { |
104 | RSA *private_key; /* Private part of server key. */ | |
105 | RSA *host_key; /* Private part of host key. */ | |
8efc0c15 | 106 | } sensitive_data; |
107 | ||
aa3378df | 108 | /* |
109 | * Flag indicating whether the current session key has been used. This flag | |
110 | * is set whenever the key is used, and cleared when the key is regenerated. | |
111 | */ | |
8efc0c15 | 112 | int key_used = 0; |
113 | ||
114 | /* This is set to true when SIGHUP is received. */ | |
115 | int received_sighup = 0; | |
116 | ||
117 | /* Public side of the server key. This value is regenerated regularly with | |
118 | the private key. */ | |
119 | RSA *public_key; | |
120 | ||
121 | /* Prototypes for various functions defined later in this file. */ | |
e7c0f9d5 | 122 | void do_connection(); |
123 | void do_authentication(char *user); | |
5260325f | 124 | void do_authloop(struct passwd * pw); |
e7c0f9d5 | 125 | void do_fake_authloop(char *user); |
5260325f | 126 | void do_authenticated(struct passwd * pw); |
127 | void do_exec_pty(const char *command, int ptyfd, int ttyfd, | |
128 | const char *ttyname, struct passwd * pw, const char *term, | |
129 | const char *display, const char *auth_proto, | |
130 | const char *auth_data); | |
131 | void do_exec_no_pty(const char *command, struct passwd * pw, | |
132 | const char *display, const char *auth_proto, | |
133 | const char *auth_data); | |
134 | void do_child(const char *command, struct passwd * pw, const char *term, | |
8efc0c15 | 135 | const char *display, const char *auth_proto, |
136 | const char *auth_data, const char *ttyname); | |
e7c0f9d5 | 137 | |
5aecb327 | 138 | #ifdef HAVE_LIBPAM |
8efc0c15 | 139 | static int pamconv(int num_msg, const struct pam_message **msg, |
5260325f | 140 | struct pam_response **resp, void *appdata_ptr); |
9c7b6dfd | 141 | void do_pam_account_and_session(char *username, char *remote_user); |
d813bc69 | 142 | void pam_cleanup_proc(void *context); |
8efc0c15 | 143 | |
144 | static struct pam_conv conv = { | |
5260325f | 145 | pamconv, |
146 | NULL | |
8efc0c15 | 147 | }; |
d813bc69 | 148 | struct pam_handle_t *pamh = NULL; |
149 | const char *pampasswd = NULL; | |
e1a9c08d | 150 | char *pamconv_msg = NULL; |
8efc0c15 | 151 | |
152 | static int pamconv(int num_msg, const struct pam_message **msg, | |
8de3263e | 153 | struct pam_response **resp, void *appdata_ptr) |
8efc0c15 | 154 | { |
5260325f | 155 | struct pam_response *reply; |
156 | int count; | |
157 | size_t msg_len; | |
158 | char *p; | |
159 | ||
160 | /* PAM will free this later */ | |
161 | reply = malloc(num_msg * sizeof(*reply)); | |
162 | if (reply == NULL) | |
163 | return PAM_CONV_ERR; | |
164 | ||
165 | for(count = 0; count < num_msg; count++) { | |
166 | switch (msg[count]->msg_style) { | |
167 | case PAM_PROMPT_ECHO_OFF: | |
168 | if (pampasswd == NULL) { | |
169 | free(reply); | |
170 | return PAM_CONV_ERR; | |
171 | } | |
172 | reply[count].resp_retcode = PAM_SUCCESS; | |
173 | reply[count].resp = xstrdup(pampasswd); | |
174 | break; | |
175 | ||
176 | case PAM_TEXT_INFO: | |
177 | reply[count].resp_retcode = PAM_SUCCESS; | |
178 | reply[count].resp = xstrdup(""); | |
179 | ||
180 | if (msg[count]->msg == NULL) | |
181 | break; | |
182 | ||
183 | debug("Adding PAM message: %s", msg[count]->msg); | |
184 | ||
185 | msg_len = strlen(msg[count]->msg); | |
186 | if (pamconv_msg) { | |
187 | size_t n = strlen(pamconv_msg); | |
188 | pamconv_msg = xrealloc(pamconv_msg, n + msg_len + 2); | |
189 | p = pamconv_msg + n; | |
190 | } else { | |
191 | pamconv_msg = p = xmalloc(msg_len + 2); | |
192 | } | |
193 | memcpy(p, msg[count]->msg, msg_len); | |
194 | p[msg_len] = '\n'; | |
195 | p[msg_len + 1] = '\0'; | |
196 | break; | |
197 | ||
198 | case PAM_PROMPT_ECHO_ON: | |
199 | case PAM_ERROR_MSG: | |
200 | default: | |
201 | free(reply); | |
202 | return PAM_CONV_ERR; | |
203 | } | |
e1a9c08d | 204 | } |
5260325f | 205 | |
206 | *resp = reply; | |
207 | ||
208 | return PAM_SUCCESS; | |
8efc0c15 | 209 | } |
210 | ||
211 | void pam_cleanup_proc(void *context) | |
212 | { | |
5260325f | 213 | int pam_retval; |
214 | ||
215 | if (pamh != NULL) | |
216 | { | |
217 | pam_retval = pam_close_session((pam_handle_t *)pamh, 0); | |
218 | if (pam_retval != PAM_SUCCESS) { | |
219 | log("Cannot close PAM session: %.200s", | |
220 | PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); | |
221 | } | |
222 | ||
223 | pam_retval = pam_end((pam_handle_t *)pamh, pam_retval); | |
224 | if (pam_retval != PAM_SUCCESS) { | |
225 | log("Cannot release PAM authentication: %.200s", | |
226 | PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); | |
227 | } | |
228 | } | |
d813bc69 | 229 | } |
230 | ||
9c7b6dfd | 231 | void do_pam_account_and_session(char *username, char *remote_user) |
d813bc69 | 232 | { |
5260325f | 233 | int pam_retval; |
234 | ||
9c7b6dfd | 235 | debug("PAM setting rhost to \"%.200s\"", get_canonical_hostname()); |
236 | pam_retval = pam_set_item((pam_handle_t *)pamh, PAM_RHOST, | |
237 | get_canonical_hostname()); | |
238 | if (pam_retval != PAM_SUCCESS) { | |
239 | log("PAM set rhost failed: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); | |
240 | do_fake_authloop(username); | |
5260325f | 241 | } |
242 | ||
243 | if (remote_user != NULL) { | |
244 | debug("PAM setting ruser to \"%.200s\"", remote_user); | |
245 | pam_retval = pam_set_item((pam_handle_t *)pamh, PAM_RUSER, remote_user); | |
246 | if (pam_retval != PAM_SUCCESS) { | |
247 | log("PAM set ruser failed: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); | |
248 | do_fake_authloop(username); | |
249 | } | |
250 | } | |
251 | ||
252 | pam_retval = pam_acct_mgmt((pam_handle_t *)pamh, 0); | |
253 | if (pam_retval != PAM_SUCCESS) { | |
254 | log("PAM rejected by account configuration: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); | |
255 | do_fake_authloop(username); | |
256 | } | |
257 | ||
258 | pam_retval = pam_open_session((pam_handle_t *)pamh, 0); | |
259 | if (pam_retval != PAM_SUCCESS) { | |
260 | log("PAM session setup failed: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); | |
261 | do_fake_authloop(username); | |
262 | } | |
8efc0c15 | 263 | } |
5aecb327 | 264 | #endif /* HAVE_LIBPAM */ |
8efc0c15 | 265 | |
5260325f | 266 | /* |
267 | * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; | |
268 | * the effect is to reread the configuration file (and to regenerate | |
269 | * the server key). | |
270 | */ | |
271 | void | |
272 | sighup_handler(int sig) | |
8efc0c15 | 273 | { |
5260325f | 274 | received_sighup = 1; |
275 | signal(SIGHUP, sighup_handler); | |
8efc0c15 | 276 | } |
277 | ||
5260325f | 278 | /* |
279 | * Called from the main program after receiving SIGHUP. | |
280 | * Restarts the server. | |
281 | */ | |
282 | void | |
283 | sighup_restart() | |
8efc0c15 | 284 | { |
5260325f | 285 | log("Received SIGHUP; restarting."); |
286 | close(listen_sock); | |
287 | execv(saved_argv[0], saved_argv); | |
288 | log("RESTART FAILED: av0='%s', error: %s.", av0, strerror(errno)); | |
289 | exit(1); | |
8efc0c15 | 290 | } |
291 | ||
5260325f | 292 | /* |
293 | * Generic signal handler for terminating signals in the master daemon. | |
294 | * These close the listen socket; not closing it seems to cause "Address | |
295 | * already in use" problems on some machines, which is inconvenient. | |
296 | */ | |
297 | void | |
298 | sigterm_handler(int sig) | |
8efc0c15 | 299 | { |
5260325f | 300 | log("Received signal %d; terminating.", sig); |
301 | close(listen_sock); | |
302 | exit(255); | |
8efc0c15 | 303 | } |
304 | ||
5260325f | 305 | /* |
306 | * SIGCHLD handler. This is called whenever a child dies. This will then | |
307 | * reap any zombies left by exited c. | |
308 | */ | |
309 | void | |
310 | main_sigchld_handler(int sig) | |
8efc0c15 | 311 | { |
5260325f | 312 | int save_errno = errno; |
313 | int status; | |
5ad13cd7 | 314 | |
5260325f | 315 | while (waitpid(-1, &status, WNOHANG) > 0) |
316 | ; | |
5ad13cd7 | 317 | |
5260325f | 318 | signal(SIGCHLD, main_sigchld_handler); |
319 | errno = save_errno; | |
8efc0c15 | 320 | } |
321 | ||
5260325f | 322 | /* |
323 | * Signal handler for the alarm after the login grace period has expired. | |
324 | */ | |
325 | void | |
326 | grace_alarm_handler(int sig) | |
8efc0c15 | 327 | { |
5260325f | 328 | /* Close the connection. */ |
329 | packet_close(); | |
8efc0c15 | 330 | |
5260325f | 331 | /* Log error and exit. */ |
332 | fatal("Timeout before authentication for %s.", get_remote_ipaddr()); | |
333 | } | |
8efc0c15 | 334 | |
5260325f | 335 | /* |
336 | * convert ssh auth msg type into description | |
337 | */ | |
338 | char * | |
339 | get_authname(int type) | |
8efc0c15 | 340 | { |
5260325f | 341 | switch (type) { |
342 | case SSH_CMSG_AUTH_PASSWORD: | |
343 | return "password"; | |
344 | case SSH_CMSG_AUTH_RSA: | |
345 | return "rsa"; | |
346 | case SSH_CMSG_AUTH_RHOSTS_RSA: | |
347 | return "rhosts-rsa"; | |
348 | case SSH_CMSG_AUTH_RHOSTS: | |
349 | return "rhosts"; | |
350 | #ifdef KRB4 | |
351 | case SSH_CMSG_AUTH_KERBEROS: | |
352 | return "kerberos"; | |
353 | #endif | |
354 | #ifdef SKEY | |
355 | case SSH_CMSG_AUTH_TIS_RESPONSE: | |
356 | return "s/key"; | |
357 | #endif | |
358 | } | |
359 | fatal("get_authname: unknown auth %d: internal error", type); | |
360 | return NULL; | |
8efc0c15 | 361 | } |
362 | ||
5260325f | 363 | /* |
364 | * Signal handler for the key regeneration alarm. Note that this | |
365 | * alarm only occurs in the daemon waiting for connections, and it does not | |
366 | * do anything with the private key or random state before forking. | |
367 | * Thus there should be no concurrency control/asynchronous execution | |
368 | * problems. | |
369 | */ | |
370 | void | |
371 | key_regeneration_alarm(int sig) | |
372 | { | |
373 | int save_errno = errno; | |
374 | ||
375 | /* Check if we should generate a new key. */ | |
376 | if (key_used) { | |
377 | /* This should really be done in the background. */ | |
378 | log("Generating new %d bit RSA key.", options.server_key_bits); | |
379 | ||
380 | if (sensitive_data.private_key != NULL) | |
381 | RSA_free(sensitive_data.private_key); | |
382 | sensitive_data.private_key = RSA_new(); | |
383 | ||
384 | if (public_key != NULL) | |
385 | RSA_free(public_key); | |
386 | public_key = RSA_new(); | |
387 | ||
388 | rsa_generate_key(sensitive_data.private_key, public_key, | |
389 | options.server_key_bits); | |
390 | arc4random_stir(); | |
391 | key_used = 0; | |
392 | log("RSA key generation complete."); | |
393 | } | |
394 | /* Reschedule the alarm. */ | |
395 | signal(SIGALRM, key_regeneration_alarm); | |
396 | alarm(options.key_regeneration_time); | |
397 | errno = save_errno; | |
398 | } | |
8efc0c15 | 399 | |
5260325f | 400 | /* |
401 | * Main program for the daemon. | |
402 | */ | |
8efc0c15 | 403 | int |
404 | main(int ac, char **av) | |
405 | { | |
5260325f | 406 | extern char *optarg; |
407 | extern int optind; | |
408 | int opt, aux, sock_in, sock_out, newsock, i, pid, on = 1; | |
409 | int remote_major, remote_minor; | |
410 | int silentrsa = 0; | |
411 | struct sockaddr_in sin; | |
412 | char buf[100]; /* Must not be larger than remote_version. */ | |
413 | char remote_version[100]; /* Must be at least as big as buf. */ | |
414 | const char *remote_ip; | |
415 | int remote_port; | |
416 | char *comment; | |
417 | FILE *f; | |
418 | struct linger linger; | |
419 | ||
420 | /* Save argv[0]. */ | |
421 | saved_argv = av; | |
422 | if (strchr(av[0], '/')) | |
423 | av0 = strrchr(av[0], '/') + 1; | |
424 | else | |
425 | av0 = av[0]; | |
426 | ||
427 | /* Initialize configuration options to their default values. */ | |
428 | initialize_server_options(&options); | |
429 | ||
430 | /* Parse command-line arguments. */ | |
431 | while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:diqQ")) != EOF) { | |
432 | switch (opt) { | |
433 | case 'f': | |
434 | config_file_name = optarg; | |
435 | break; | |
436 | case 'd': | |
437 | debug_flag = 1; | |
438 | options.log_level = SYSLOG_LEVEL_DEBUG; | |
439 | break; | |
440 | case 'i': | |
441 | inetd_flag = 1; | |
442 | break; | |
443 | case 'Q': | |
444 | silentrsa = 1; | |
445 | break; | |
446 | case 'q': | |
447 | options.log_level = SYSLOG_LEVEL_QUIET; | |
448 | break; | |
449 | case 'b': | |
450 | options.server_key_bits = atoi(optarg); | |
451 | break; | |
452 | case 'p': | |
453 | options.port = atoi(optarg); | |
454 | break; | |
455 | case 'g': | |
456 | options.login_grace_time = atoi(optarg); | |
457 | break; | |
458 | case 'k': | |
459 | options.key_regeneration_time = atoi(optarg); | |
460 | break; | |
461 | case 'h': | |
462 | options.host_key_file = optarg; | |
463 | break; | |
464 | case 'V': | |
465 | client_version_string = optarg; | |
466 | /* only makes sense with inetd_flag, i.e. no listen() */ | |
467 | inetd_flag = 1; | |
468 | break; | |
469 | case '?': | |
470 | default: | |
471 | fprintf(stderr, "sshd version %s\n", SSH_VERSION); | |
472 | fprintf(stderr, "Usage: %s [options]\n", av0); | |
473 | fprintf(stderr, "Options:\n"); | |
aa3378df | 474 | fprintf(stderr, " -f file Configuration file (default %s)\n", SERVER_CONFIG_FILE); |
5260325f | 475 | fprintf(stderr, " -d Debugging mode\n"); |
476 | fprintf(stderr, " -i Started from inetd\n"); | |
477 | fprintf(stderr, " -q Quiet (no logging)\n"); | |
478 | fprintf(stderr, " -p port Listen on the specified port (default: 22)\n"); | |
479 | fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n"); | |
480 | fprintf(stderr, " -g seconds Grace period for authentication (default: 300)\n"); | |
481 | fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n"); | |
482 | fprintf(stderr, " -h file File from which to read host key (default: %s)\n", | |
483 | HOST_KEY_FILE); | |
484 | exit(1); | |
485 | } | |
486 | } | |
487 | ||
488 | /* check if RSA support exists */ | |
489 | if (rsa_alive() == 0) { | |
490 | if (silentrsa == 0) | |
491 | printf("sshd: no RSA support in libssl and libcrypto -- exiting. See ssl(8)\n"); | |
492 | log("no RSA support in libssl and libcrypto -- exiting. See ssl(8)"); | |
493 | exit(1); | |
494 | } | |
495 | /* Read server configuration options from the configuration file. */ | |
496 | read_server_config(&options, config_file_name); | |
497 | ||
498 | /* Fill in default values for those options not explicitly set. */ | |
499 | fill_default_server_options(&options); | |
500 | ||
501 | /* Check certain values for sanity. */ | |
502 | if (options.server_key_bits < 512 || | |
503 | options.server_key_bits > 32768) { | |
504 | fprintf(stderr, "Bad server key size.\n"); | |
505 | exit(1); | |
506 | } | |
507 | if (options.port < 1 || options.port > 65535) { | |
508 | fprintf(stderr, "Bad port number.\n"); | |
509 | exit(1); | |
510 | } | |
511 | /* Check that there are no remaining arguments. */ | |
512 | if (optind < ac) { | |
513 | fprintf(stderr, "Extra argument %s.\n", av[optind]); | |
514 | exit(1); | |
8efc0c15 | 515 | } |
5260325f | 516 | /* Force logging to stderr while loading the private host key |
517 | unless started from inetd */ | |
518 | log_init(av0, options.log_level, options.log_facility, !inetd_flag); | |
519 | ||
520 | debug("sshd version %.100s", SSH_VERSION); | |
521 | ||
522 | sensitive_data.host_key = RSA_new(); | |
523 | errno = 0; | |
524 | /* Load the host key. It must have empty passphrase. */ | |
525 | if (!load_private_key(options.host_key_file, "", | |
526 | sensitive_data.host_key, &comment)) { | |
527 | error("Could not load host key: %.200s: %.100s", | |
528 | options.host_key_file, strerror(errno)); | |
529 | exit(1); | |
530 | } | |
531 | xfree(comment); | |
532 | ||
533 | /* Initialize the log (it is reinitialized below in case we | |
534 | forked). */ | |
535 | if (debug_flag && !inetd_flag) | |
536 | log_stderr = 1; | |
537 | log_init(av0, options.log_level, options.log_facility, log_stderr); | |
538 | ||
539 | /* If not in debugging mode, and not started from inetd, | |
540 | disconnect from the controlling terminal, and fork. The | |
541 | original process exits. */ | |
542 | if (!debug_flag && !inetd_flag) { | |
8efc0c15 | 543 | #ifdef TIOCNOTTY |
5260325f | 544 | int fd; |
8efc0c15 | 545 | #endif /* TIOCNOTTY */ |
5260325f | 546 | if (daemon(0, 0) < 0) |
547 | fatal("daemon() failed: %.200s", strerror(errno)); | |
548 | ||
549 | /* Disconnect from the controlling tty. */ | |
8efc0c15 | 550 | #ifdef TIOCNOTTY |
5260325f | 551 | fd = open("/dev/tty", O_RDWR | O_NOCTTY); |
552 | if (fd >= 0) { | |
553 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
554 | close(fd); | |
555 | } | |
8efc0c15 | 556 | #endif /* TIOCNOTTY */ |
8efc0c15 | 557 | } |
5260325f | 558 | /* Reinitialize the log (because of the fork above). */ |
559 | log_init(av0, options.log_level, options.log_facility, log_stderr); | |
560 | ||
561 | /* Check that server and host key lengths differ sufficiently. | |
562 | This is necessary to make double encryption work with rsaref. | |
563 | Oh, I hate software patents. I dont know if this can go? Niels */ | |
564 | if (options.server_key_bits > | |
565 | BN_num_bits(sensitive_data.host_key->n) - SSH_KEY_BITS_RESERVED && | |
566 | options.server_key_bits < | |
567 | BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) { | |
568 | options.server_key_bits = | |
569 | BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED; | |
570 | debug("Forcing server key to %d bits to make it differ from host key.", | |
571 | options.server_key_bits); | |
8efc0c15 | 572 | } |
5260325f | 573 | /* Do not display messages to stdout in RSA code. */ |
574 | rsa_set_verbose(0); | |
575 | ||
576 | /* Initialize the random number generator. */ | |
577 | arc4random_stir(); | |
578 | ||
579 | /* Chdir to the root directory so that the current disk can be | |
580 | unmounted if desired. */ | |
581 | chdir("/"); | |
582 | ||
583 | /* Close connection cleanly after attack. */ | |
584 | cipher_attack_detected = packet_disconnect; | |
585 | ||
586 | /* Start listening for a socket, unless started from inetd. */ | |
587 | if (inetd_flag) { | |
588 | int s1, s2; | |
589 | s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */ | |
590 | s2 = dup(s1); | |
591 | sock_in = dup(0); | |
592 | sock_out = dup(1); | |
593 | /* We intentionally do not close the descriptors 0, 1, and 2 | |
594 | as our code for setting the descriptors won\'t work | |
595 | if ttyfd happens to be one of those. */ | |
596 | debug("inetd sockets after dupping: %d, %d", sock_in, sock_out); | |
597 | ||
598 | public_key = RSA_new(); | |
599 | sensitive_data.private_key = RSA_new(); | |
600 | ||
601 | log("Generating %d bit RSA key.", options.server_key_bits); | |
602 | rsa_generate_key(sensitive_data.private_key, public_key, | |
603 | options.server_key_bits); | |
604 | arc4random_stir(); | |
605 | log("RSA key generation complete."); | |
606 | } else { | |
607 | /* Create socket for listening. */ | |
608 | listen_sock = socket(AF_INET, SOCK_STREAM, 0); | |
609 | if (listen_sock < 0) | |
610 | fatal("socket: %.100s", strerror(errno)); | |
611 | ||
612 | /* Set socket options. We try to make the port reusable | |
613 | and have it close as fast as possible without waiting | |
614 | in unnecessary wait states on close. */ | |
615 | setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, (void *) &on, | |
616 | sizeof(on)); | |
617 | linger.l_onoff = 1; | |
618 | linger.l_linger = 5; | |
619 | setsockopt(listen_sock, SOL_SOCKET, SO_LINGER, (void *) &linger, | |
620 | sizeof(linger)); | |
621 | ||
5260325f | 622 | memset(&sin, 0, sizeof(sin)); |
623 | sin.sin_family = AF_INET; | |
624 | sin.sin_addr = options.listen_addr; | |
625 | sin.sin_port = htons(options.port); | |
626 | ||
5260325f | 627 | if (bind(listen_sock, (struct sockaddr *) & sin, sizeof(sin)) < 0) { |
628 | error("bind: %.100s", strerror(errno)); | |
629 | shutdown(listen_sock, SHUT_RDWR); | |
630 | close(listen_sock); | |
631 | fatal("Bind to port %d failed.", options.port); | |
632 | } | |
633 | if (!debug_flag) { | |
aa3378df | 634 | /* |
635 | * Record our pid in /etc/sshd_pid to make it easier | |
636 | * to kill the correct sshd. We don\'t want to do | |
637 | * this before the bind above because the bind will | |
638 | * fail if there already is a daemon, and this will | |
639 | * overwrite any old pid in the file. | |
640 | */ | |
5260325f | 641 | f = fopen(SSH_DAEMON_PID_FILE, "w"); |
642 | if (f) { | |
643 | fprintf(f, "%u\n", (unsigned int) getpid()); | |
644 | fclose(f); | |
645 | } | |
8efc0c15 | 646 | } |
8efc0c15 | 647 | |
5260325f | 648 | log("Server listening on port %d.", options.port); |
649 | if (listen(listen_sock, 5) < 0) | |
650 | fatal("listen: %.100s", strerror(errno)); | |
651 | ||
652 | public_key = RSA_new(); | |
653 | sensitive_data.private_key = RSA_new(); | |
654 | ||
655 | log("Generating %d bit RSA key.", options.server_key_bits); | |
656 | rsa_generate_key(sensitive_data.private_key, public_key, | |
657 | options.server_key_bits); | |
658 | arc4random_stir(); | |
659 | log("RSA key generation complete."); | |
660 | ||
661 | /* Schedule server key regeneration alarm. */ | |
662 | signal(SIGALRM, key_regeneration_alarm); | |
663 | alarm(options.key_regeneration_time); | |
664 | ||
665 | /* Arrange to restart on SIGHUP. The handler needs listen_sock. */ | |
666 | signal(SIGHUP, sighup_handler); | |
667 | signal(SIGTERM, sigterm_handler); | |
668 | signal(SIGQUIT, sigterm_handler); | |
669 | ||
670 | /* Arrange SIGCHLD to be caught. */ | |
671 | signal(SIGCHLD, main_sigchld_handler); | |
672 | ||
aa3378df | 673 | /* |
674 | * Stay listening for connections until the system crashes or | |
675 | * the daemon is killed with a signal. | |
676 | */ | |
5260325f | 677 | for (;;) { |
678 | if (received_sighup) | |
679 | sighup_restart(); | |
680 | /* Wait in accept until there is a connection. */ | |
681 | aux = sizeof(sin); | |
682 | newsock = accept(listen_sock, (struct sockaddr *) & sin, &aux); | |
683 | if (received_sighup) | |
684 | sighup_restart(); | |
685 | if (newsock < 0) { | |
686 | if (errno == EINTR) | |
687 | continue; | |
688 | error("accept: %.100s", strerror(errno)); | |
689 | continue; | |
690 | } | |
aa3378df | 691 | /* |
692 | * Got connection. Fork a child to handle it, unless | |
693 | * we are in debugging mode. | |
694 | */ | |
5260325f | 695 | if (debug_flag) { |
aa3378df | 696 | /* |
697 | * In debugging mode. Close the listening | |
698 | * socket, and start processing the | |
699 | * connection without forking. | |
700 | */ | |
5260325f | 701 | debug("Server will not fork when running in debugging mode."); |
702 | close(listen_sock); | |
703 | sock_in = newsock; | |
704 | sock_out = newsock; | |
705 | pid = getpid(); | |
706 | break; | |
707 | } else { | |
aa3378df | 708 | /* |
709 | * Normal production daemon. Fork, and have | |
710 | * the child process the connection. The | |
711 | * parent continues listening. | |
712 | */ | |
5260325f | 713 | if ((pid = fork()) == 0) { |
aa3378df | 714 | /* |
715 | * Child. Close the listening socket, and start using the | |
716 | * accepted socket. Reinitialize logging (since our pid has | |
717 | * changed). We break out of the loop to handle the connection. | |
718 | */ | |
5260325f | 719 | close(listen_sock); |
720 | sock_in = newsock; | |
721 | sock_out = newsock; | |
722 | log_init(av0, options.log_level, options.log_facility, log_stderr); | |
723 | break; | |
724 | } | |
725 | } | |
726 | ||
727 | /* Parent. Stay in the loop. */ | |
728 | if (pid < 0) | |
729 | error("fork: %.100s", strerror(errno)); | |
730 | else | |
731 | debug("Forked child %d.", pid); | |
732 | ||
733 | /* Mark that the key has been used (it was "given" to the child). */ | |
734 | key_used = 1; | |
735 | ||
736 | arc4random_stir(); | |
737 | ||
738 | /* Close the new socket (the child is now taking care of it). */ | |
739 | close(newsock); | |
740 | } | |
741 | } | |
8efc0c15 | 742 | |
5260325f | 743 | /* This is the child processing a new connection. */ |
744 | ||
aa3378df | 745 | /* |
746 | * Disable the key regeneration alarm. We will not regenerate the | |
747 | * key since we are no longer in a position to give it to anyone. We | |
748 | * will not restart on SIGHUP since it no longer makes sense. | |
749 | */ | |
5260325f | 750 | alarm(0); |
751 | signal(SIGALRM, SIG_DFL); | |
752 | signal(SIGHUP, SIG_DFL); | |
753 | signal(SIGTERM, SIG_DFL); | |
754 | signal(SIGQUIT, SIG_DFL); | |
755 | signal(SIGCHLD, SIG_DFL); | |
756 | ||
aa3378df | 757 | /* |
758 | * Set socket options for the connection. We want the socket to | |
759 | * close as fast as possible without waiting for anything. If the | |
760 | * connection is not a socket, these will do nothing. | |
761 | */ | |
762 | /* setsockopt(sock_in, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */ | |
5260325f | 763 | linger.l_onoff = 1; |
764 | linger.l_linger = 5; | |
765 | setsockopt(sock_in, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger)); | |
766 | ||
aa3378df | 767 | /* |
768 | * Register our connection. This turns encryption off because we do | |
769 | * not have a key. | |
770 | */ | |
5260325f | 771 | packet_set_connection(sock_in, sock_out); |
772 | ||
773 | remote_port = get_remote_port(); | |
774 | remote_ip = get_remote_ipaddr(); | |
775 | ||
776 | /* Check whether logins are denied from this host. */ | |
777 | #ifdef LIBWRAP | |
778 | { | |
779 | struct request_info req; | |
8efc0c15 | 780 | |
5260325f | 781 | request_init(&req, RQ_DAEMON, av0, RQ_FILE, sock_in, NULL); |
782 | fromhost(&req); | |
8efc0c15 | 783 | |
5260325f | 784 | if (!hosts_access(&req)) { |
785 | close(sock_in); | |
786 | close(sock_out); | |
787 | refuse(&req); | |
788 | } | |
789 | verbose("Connection from %.500s port %d", eval_client(&req), remote_port); | |
8efc0c15 | 790 | } |
8efc0c15 | 791 | #else |
5260325f | 792 | /* Log the connection. */ |
793 | verbose("Connection from %.500s port %d", remote_ip, remote_port); | |
8efc0c15 | 794 | #endif /* LIBWRAP */ |
795 | ||
aa3378df | 796 | /* |
797 | * We don\'t want to listen forever unless the other side | |
798 | * successfully authenticates itself. So we set up an alarm which is | |
799 | * cleared after successful authentication. A limit of zero | |
800 | * indicates no limit. Note that we don\'t set the alarm in debugging | |
801 | * mode; it is just annoying to have the server exit just when you | |
802 | * are about to discover the bug. | |
803 | */ | |
5260325f | 804 | signal(SIGALRM, grace_alarm_handler); |
805 | if (!debug_flag) | |
806 | alarm(options.login_grace_time); | |
807 | ||
808 | if (client_version_string != NULL) { | |
809 | /* we are exec'ed by sshd2, so skip exchange of protocol version */ | |
810 | strlcpy(buf, client_version_string, sizeof(buf)); | |
811 | } else { | |
812 | /* Send our protocol version identification. */ | |
813 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", | |
814 | PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION); | |
a408af76 | 815 | if (atomicio(write, sock_out, buf, strlen(buf)) != strlen(buf)) |
5260325f | 816 | fatal("Could not write ident string to %s.", get_remote_ipaddr()); |
817 | ||
818 | /* Read other side\'s version identification. */ | |
819 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
820 | if (read(sock_in, &buf[i], 1) != 1) | |
821 | fatal("Did not receive ident string from %s.", get_remote_ipaddr()); | |
822 | if (buf[i] == '\r') { | |
823 | buf[i] = '\n'; | |
824 | buf[i + 1] = 0; | |
825 | break; | |
826 | } | |
827 | if (buf[i] == '\n') { | |
828 | /* buf[i] == '\n' */ | |
829 | buf[i + 1] = 0; | |
830 | break; | |
831 | } | |
832 | } | |
833 | buf[sizeof(buf) - 1] = 0; | |
8efc0c15 | 834 | } |
5260325f | 835 | |
aa3378df | 836 | /* |
837 | * Check that the versions match. In future this might accept | |
838 | * several versions and set appropriate flags to handle them. | |
839 | */ | |
5260325f | 840 | if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor, |
a408af76 | 841 | remote_version) != 3) { |
842 | char *s = "Protocol mismatch.\n"; | |
843 | ||
844 | (void) atomicio(write, sock_out, s, strlen(s)); | |
5260325f | 845 | close(sock_in); |
846 | close(sock_out); | |
847 | fatal("Bad protocol version identification '%.100s' from %s", | |
848 | buf, get_remote_ipaddr()); | |
849 | } | |
850 | debug("Client protocol version %d.%d; client software version %.100s", | |
851 | remote_major, remote_minor, remote_version); | |
852 | if (remote_major != PROTOCOL_MAJOR) { | |
a408af76 | 853 | char *s = "Protocol major versions differ.\n"; |
854 | ||
855 | (void) atomicio(write, sock_out, s, strlen(s)); | |
5260325f | 856 | close(sock_in); |
857 | close(sock_out); | |
858 | fatal("Protocol major versions differ for %s: %d vs. %d", | |
859 | get_remote_ipaddr(), | |
860 | PROTOCOL_MAJOR, remote_major); | |
8efc0c15 | 861 | } |
5260325f | 862 | /* Check that the client has sufficiently high software version. */ |
863 | if (remote_major == 1 && remote_minor < 3) | |
864 | packet_disconnect("Your ssh version is too old and is no longer supported. Please install a newer version."); | |
865 | ||
866 | if (remote_major == 1 && remote_minor == 3) { | |
867 | enable_compat13(); | |
868 | if (strcmp(remote_version, "OpenSSH-1.1") != 0) { | |
869 | debug("Agent forwarding disabled, remote version is not compatible."); | |
870 | no_agent_forwarding_flag = 1; | |
871 | } | |
872 | } | |
aa3378df | 873 | /* |
874 | * Check that the connection comes from a privileged port. Rhosts- | |
875 | * and Rhosts-RSA-Authentication only make sense from priviledged | |
876 | * programs. Of course, if the intruder has root access on his local | |
877 | * machine, he can connect from any port. So do not use these | |
878 | * authentication methods from machines that you do not trust. | |
879 | */ | |
5260325f | 880 | if (remote_port >= IPPORT_RESERVED || |
881 | remote_port < IPPORT_RESERVED / 2) { | |
882 | options.rhosts_authentication = 0; | |
883 | options.rhosts_rsa_authentication = 0; | |
884 | } | |
885 | packet_set_nonblocking(); | |
886 | ||
887 | /* Handle the connection. */ | |
888 | do_connection(); | |
8efc0c15 | 889 | |
890 | #ifdef KRB4 | |
5260325f | 891 | /* Cleanup user's ticket cache file. */ |
892 | if (options.kerberos_ticket_cleanup) | |
893 | (void) dest_tkt(); | |
8efc0c15 | 894 | #endif /* KRB4 */ |
895 | ||
5260325f | 896 | /* Cleanup user's local Xauthority file. */ |
897 | if (xauthfile) | |
898 | unlink(xauthfile); | |
8efc0c15 | 899 | |
5260325f | 900 | /* The connection has been terminated. */ |
901 | verbose("Closing connection to %.100s", remote_ip); | |
8efc0c15 | 902 | |
5aecb327 | 903 | #ifdef HAVE_LIBPAM |
5260325f | 904 | { |
905 | int retval; | |
8efc0c15 | 906 | |
5260325f | 907 | if (pamh != NULL) { |
908 | debug("Closing PAM session."); | |
909 | retval = pam_close_session((pam_handle_t *)pamh, 0); | |
8efc0c15 | 910 | |
5260325f | 911 | debug("Terminating PAM library."); |
912 | if (pam_end((pam_handle_t *)pamh, retval) != PAM_SUCCESS) | |
913 | log("Cannot release PAM authentication."); | |
914 | ||
915 | fatal_remove_cleanup(&pam_cleanup_proc, NULL); | |
916 | } | |
917 | } | |
918 | #endif /* HAVE_LIBPAM */ | |
8efc0c15 | 919 | |
5260325f | 920 | packet_close(); |
921 | exit(0); | |
922 | } | |
8efc0c15 | 923 | |
5260325f | 924 | /* |
925 | * Process an incoming connection. Protocol version identifiers have already | |
926 | * been exchanged. This sends server key and performs the key exchange. | |
927 | * Server and host keys will no longer be needed after this functions. | |
928 | */ | |
e7c0f9d5 | 929 | void |
930 | do_connection() | |
8efc0c15 | 931 | { |
5260325f | 932 | int i, len; |
933 | BIGNUM *session_key_int; | |
934 | unsigned char session_key[SSH_SESSION_KEY_LENGTH]; | |
935 | unsigned char check_bytes[8]; | |
936 | char *user; | |
937 | unsigned int cipher_type, auth_mask, protocol_flags; | |
938 | int plen, slen; | |
939 | u_int32_t rand = 0; | |
940 | ||
aa3378df | 941 | /* |
942 | * Generate check bytes that the client must send back in the user | |
943 | * packet in order for it to be accepted; this is used to defy ip | |
944 | * spoofing attacks. Note that this only works against somebody | |
945 | * doing IP spoofing from a remote machine; any machine on the local | |
946 | * network can still see outgoing packets and catch the random | |
947 | * cookie. This only affects rhosts authentication, and this is one | |
948 | * of the reasons why it is inherently insecure. | |
949 | */ | |
5260325f | 950 | for (i = 0; i < 8; i++) { |
951 | if (i % 4 == 0) | |
952 | rand = arc4random(); | |
953 | check_bytes[i] = rand & 0xff; | |
954 | rand >>= 8; | |
955 | } | |
956 | ||
aa3378df | 957 | /* |
958 | * Send our public key. We include in the packet 64 bits of random | |
959 | * data that must be matched in the reply in order to prevent IP | |
960 | * spoofing. | |
961 | */ | |
5260325f | 962 | packet_start(SSH_SMSG_PUBLIC_KEY); |
963 | for (i = 0; i < 8; i++) | |
964 | packet_put_char(check_bytes[i]); | |
965 | ||
966 | /* Store our public server RSA key. */ | |
967 | packet_put_int(BN_num_bits(public_key->n)); | |
968 | packet_put_bignum(public_key->e); | |
969 | packet_put_bignum(public_key->n); | |
970 | ||
971 | /* Store our public host RSA key. */ | |
972 | packet_put_int(BN_num_bits(sensitive_data.host_key->n)); | |
973 | packet_put_bignum(sensitive_data.host_key->e); | |
974 | packet_put_bignum(sensitive_data.host_key->n); | |
975 | ||
976 | /* Put protocol flags. */ | |
977 | packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); | |
978 | ||
979 | /* Declare which ciphers we support. */ | |
980 | packet_put_int(cipher_mask()); | |
981 | ||
982 | /* Declare supported authentication types. */ | |
983 | auth_mask = 0; | |
984 | if (options.rhosts_authentication) | |
985 | auth_mask |= 1 << SSH_AUTH_RHOSTS; | |
986 | if (options.rhosts_rsa_authentication) | |
987 | auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; | |
988 | if (options.rsa_authentication) | |
989 | auth_mask |= 1 << SSH_AUTH_RSA; | |
8efc0c15 | 990 | #ifdef KRB4 |
5260325f | 991 | if (options.kerberos_authentication) |
992 | auth_mask |= 1 << SSH_AUTH_KERBEROS; | |
8efc0c15 | 993 | #endif |
994 | #ifdef AFS | |
5260325f | 995 | if (options.kerberos_tgt_passing) |
996 | auth_mask |= 1 << SSH_PASS_KERBEROS_TGT; | |
997 | if (options.afs_token_passing) | |
998 | auth_mask |= 1 << SSH_PASS_AFS_TOKEN; | |
8efc0c15 | 999 | #endif |
5260325f | 1000 | #ifdef SKEY |
1001 | if (options.skey_authentication == 1) | |
1002 | auth_mask |= 1 << SSH_AUTH_TIS; | |
1003 | #endif | |
1004 | if (options.password_authentication) | |
1005 | auth_mask |= 1 << SSH_AUTH_PASSWORD; | |
1006 | packet_put_int(auth_mask); | |
1007 | ||
1008 | /* Send the packet and wait for it to be sent. */ | |
1009 | packet_send(); | |
1010 | packet_write_wait(); | |
1011 | ||
1012 | debug("Sent %d bit public key and %d bit host key.", | |
1013 | BN_num_bits(public_key->n), BN_num_bits(sensitive_data.host_key->n)); | |
1014 | ||
1015 | /* Read clients reply (cipher type and session key). */ | |
1016 | packet_read_expect(&plen, SSH_CMSG_SESSION_KEY); | |
1017 | ||
1018 | /* Get cipher type. */ | |
1019 | cipher_type = packet_get_char(); | |
1020 | ||
1021 | /* Get check bytes from the packet. These must match those we | |
1022 | sent earlier with the public key packet. */ | |
1023 | for (i = 0; i < 8; i++) | |
1024 | if (check_bytes[i] != packet_get_char()) | |
1025 | packet_disconnect("IP Spoofing check bytes do not match."); | |
1026 | ||
1027 | debug("Encryption type: %.200s", cipher_name(cipher_type)); | |
1028 | ||
1029 | /* Get the encrypted integer. */ | |
1030 | session_key_int = BN_new(); | |
1031 | packet_get_bignum(session_key_int, &slen); | |
1032 | ||
5260325f | 1033 | protocol_flags = packet_get_int(); |
1034 | packet_set_protocol_flags(protocol_flags); | |
1035 | ||
1036 | packet_integrity_check(plen, 1 + 8 + slen + 4, SSH_CMSG_SESSION_KEY); | |
1037 | ||
aa3378df | 1038 | /* |
1039 | * Decrypt it using our private server key and private host key (key | |
1040 | * with larger modulus first). | |
1041 | */ | |
5260325f | 1042 | if (BN_cmp(sensitive_data.private_key->n, sensitive_data.host_key->n) > 0) { |
1043 | /* Private key has bigger modulus. */ | |
1044 | if (BN_num_bits(sensitive_data.private_key->n) < | |
1045 | BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) { | |
1046 | fatal("do_connection: %s: private_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", | |
1047 | get_remote_ipaddr(), | |
1048 | BN_num_bits(sensitive_data.private_key->n), | |
1049 | BN_num_bits(sensitive_data.host_key->n), | |
1050 | SSH_KEY_BITS_RESERVED); | |
1051 | } | |
1052 | rsa_private_decrypt(session_key_int, session_key_int, | |
1053 | sensitive_data.private_key); | |
1054 | rsa_private_decrypt(session_key_int, session_key_int, | |
1055 | sensitive_data.host_key); | |
1056 | } else { | |
1057 | /* Host key has bigger modulus (or they are equal). */ | |
1058 | if (BN_num_bits(sensitive_data.host_key->n) < | |
1059 | BN_num_bits(sensitive_data.private_key->n) + SSH_KEY_BITS_RESERVED) { | |
1060 | fatal("do_connection: %s: host_key %d < private_key %d + SSH_KEY_BITS_RESERVED %d", | |
1061 | get_remote_ipaddr(), | |
1062 | BN_num_bits(sensitive_data.host_key->n), | |
1063 | BN_num_bits(sensitive_data.private_key->n), | |
1064 | SSH_KEY_BITS_RESERVED); | |
1065 | } | |
1066 | rsa_private_decrypt(session_key_int, session_key_int, | |
1067 | sensitive_data.host_key); | |
1068 | rsa_private_decrypt(session_key_int, session_key_int, | |
1069 | sensitive_data.private_key); | |
1070 | } | |
1071 | ||
5260325f | 1072 | compute_session_id(session_id, check_bytes, |
1073 | sensitive_data.host_key->n, | |
1074 | sensitive_data.private_key->n); | |
1075 | ||
aa3378df | 1076 | /* |
1077 | * Extract session key from the decrypted integer. The key is in the | |
1078 | * least significant 256 bits of the integer; the first byte of the | |
1079 | * key is in the highest bits. | |
1080 | */ | |
5260325f | 1081 | BN_mask_bits(session_key_int, sizeof(session_key) * 8); |
1082 | len = BN_num_bytes(session_key_int); | |
1083 | if (len < 0 || len > sizeof(session_key)) | |
1084 | fatal("do_connection: bad len from %s: session_key_int %d > sizeof(session_key) %d", | |
1085 | get_remote_ipaddr(), | |
1086 | len, sizeof(session_key)); | |
1087 | memset(session_key, 0, sizeof(session_key)); | |
1088 | BN_bn2bin(session_key_int, session_key + sizeof(session_key) - len); | |
1089 | ||
1090 | /* Xor the first 16 bytes of the session key with the session id. */ | |
1091 | for (i = 0; i < 16; i++) | |
1092 | session_key[i] ^= session_id[i]; | |
1093 | ||
1094 | /* Destroy the decrypted integer. It is no longer needed. */ | |
1095 | BN_clear_free(session_key_int); | |
1096 | ||
1097 | /* Set the session key. From this on all communications will be encrypted. */ | |
1098 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); | |
1099 | ||
1100 | /* Destroy our copy of the session key. It is no longer needed. */ | |
1101 | memset(session_key, 0, sizeof(session_key)); | |
1102 | ||
1103 | debug("Received session key; encryption turned on."); | |
1104 | ||
1105 | /* Send an acknowledgement packet. Note that this packet is sent encrypted. */ | |
1106 | packet_start(SSH_SMSG_SUCCESS); | |
1107 | packet_send(); | |
1108 | packet_write_wait(); | |
1109 | ||
1110 | /* Get the name of the user that we wish to log in as. */ | |
1111 | packet_read_expect(&plen, SSH_CMSG_USER); | |
1112 | ||
1113 | /* Get the user name. */ | |
1114 | { | |
1115 | int ulen; | |
1116 | user = packet_get_string(&ulen); | |
1117 | packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER); | |
1118 | } | |
1119 | ||
1120 | /* Destroy the private and public keys. They will no longer be needed. */ | |
1121 | RSA_free(public_key); | |
1122 | RSA_free(sensitive_data.private_key); | |
1123 | RSA_free(sensitive_data.host_key); | |
8efc0c15 | 1124 | |
5260325f | 1125 | setproctitle("%s", user); |
1126 | /* Do the authentication. */ | |
1127 | do_authentication(user); | |
1128 | } | |
8efc0c15 | 1129 | |
5260325f | 1130 | /* |
1131 | * Check if the user is allowed to log in via ssh. If user is listed in | |
1132 | * DenyUsers or user's primary group is listed in DenyGroups, false will | |
1133 | * be returned. If AllowUsers isn't empty and user isn't listed there, or | |
1134 | * if AllowGroups isn't empty and user isn't listed there, false will be | |
1135 | * returned. Otherwise true is returned. | |
1136 | * XXX This function should also check if user has a valid shell | |
1137 | */ | |
8efc0c15 | 1138 | static int |
5260325f | 1139 | allowed_user(struct passwd * pw) |
8efc0c15 | 1140 | { |
5260325f | 1141 | struct group *grp; |
1142 | int i; | |
1143 | ||
1144 | /* Shouldn't be called if pw is NULL, but better safe than sorry... */ | |
1145 | if (!pw) | |
1146 | return 0; | |
1147 | ||
1148 | /* XXX Should check for valid login shell */ | |
1149 | ||
1150 | /* Return false if user is listed in DenyUsers */ | |
1151 | if (options.num_deny_users > 0) { | |
1152 | if (!pw->pw_name) | |
1153 | return 0; | |
1154 | for (i = 0; i < options.num_deny_users; i++) | |
1155 | if (match_pattern(pw->pw_name, options.deny_users[i])) | |
1156 | return 0; | |
1157 | } | |
aa3378df | 1158 | /* Return false if AllowUsers isn't empty and user isn't listed there */ |
5260325f | 1159 | if (options.num_allow_users > 0) { |
1160 | if (!pw->pw_name) | |
1161 | return 0; | |
1162 | for (i = 0; i < options.num_allow_users; i++) | |
1163 | if (match_pattern(pw->pw_name, options.allow_users[i])) | |
1164 | break; | |
1165 | /* i < options.num_allow_users iff we break for loop */ | |
1166 | if (i >= options.num_allow_users) | |
1167 | return 0; | |
1168 | } | |
1169 | /* Get the primary group name if we need it. Return false if it fails */ | |
1170 | if (options.num_deny_groups > 0 || options.num_allow_groups > 0) { | |
1171 | grp = getgrgid(pw->pw_gid); | |
1172 | if (!grp) | |
1173 | return 0; | |
1174 | ||
1175 | /* Return false if user's group is listed in DenyGroups */ | |
1176 | if (options.num_deny_groups > 0) { | |
1177 | if (!grp->gr_name) | |
1178 | return 0; | |
1179 | for (i = 0; i < options.num_deny_groups; i++) | |
1180 | if (match_pattern(grp->gr_name, options.deny_groups[i])) | |
1181 | return 0; | |
1182 | } | |
aa3378df | 1183 | /* |
1184 | * Return false if AllowGroups isn't empty and user's group | |
1185 | * isn't listed there | |
1186 | */ | |
5260325f | 1187 | if (options.num_allow_groups > 0) { |
1188 | if (!grp->gr_name) | |
1189 | return 0; | |
1190 | for (i = 0; i < options.num_allow_groups; i++) | |
1191 | if (match_pattern(grp->gr_name, options.allow_groups[i])) | |
1192 | break; | |
1193 | /* i < options.num_allow_groups iff we break for | |
1194 | loop */ | |
1195 | if (i >= options.num_allow_groups) | |
1196 | return 0; | |
1197 | } | |
1198 | } | |
1199 | /* We found no reason not to let this user try to log on... */ | |
1200 | return 1; | |
8efc0c15 | 1201 | } |
1202 | ||
5260325f | 1203 | /* |
1204 | * Performs authentication of an incoming connection. Session key has already | |
1205 | * been exchanged and encryption is enabled. User is the user name to log | |
1206 | * in as (received from the client). | |
1207 | */ | |
8efc0c15 | 1208 | void |
e7c0f9d5 | 1209 | do_authentication(char *user) |
8efc0c15 | 1210 | { |
5260325f | 1211 | struct passwd *pw, pwcopy; |
e7c0f9d5 | 1212 | |
8efc0c15 | 1213 | #ifdef AFS |
5260325f | 1214 | /* If machine has AFS, set process authentication group. */ |
1215 | if (k_hasafs()) { | |
1216 | k_setpag(); | |
1217 | k_unlog(); | |
1218 | } | |
8efc0c15 | 1219 | #endif /* AFS */ |
5260325f | 1220 | |
1221 | /* Verify that the user is a valid user. */ | |
1222 | pw = getpwnam(user); | |
1223 | if (!pw || !allowed_user(pw)) | |
1224 | do_fake_authloop(user); | |
1225 | ||
1226 | /* Take a copy of the returned structure. */ | |
1227 | memset(&pwcopy, 0, sizeof(pwcopy)); | |
1228 | pwcopy.pw_name = xstrdup(pw->pw_name); | |
1229 | pwcopy.pw_passwd = xstrdup(pw->pw_passwd); | |
1230 | pwcopy.pw_uid = pw->pw_uid; | |
1231 | pwcopy.pw_gid = pw->pw_gid; | |
1232 | pwcopy.pw_dir = xstrdup(pw->pw_dir); | |
1233 | pwcopy.pw_shell = xstrdup(pw->pw_shell); | |
1234 | pw = &pwcopy; | |
8efc0c15 | 1235 | |
5aecb327 | 1236 | #ifdef HAVE_LIBPAM |
5260325f | 1237 | { |
1238 | int pam_retval; | |
1239 | ||
1240 | debug("Starting up PAM with username \"%.200s\"", pw->pw_name); | |
e7c0f9d5 | 1241 | |
5260325f | 1242 | pam_retval = pam_start("sshd", pw->pw_name, &conv, (pam_handle_t**)&pamh); |
1243 | if (pam_retval != PAM_SUCCESS) | |
1244 | fatal("PAM initialisation failed: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); | |
e7c0f9d5 | 1245 | |
5260325f | 1246 | fatal_add_cleanup(&pam_cleanup_proc, NULL); |
1247 | } | |
5aecb327 | 1248 | #endif |
0183ea1c | 1249 | |
aa3378df | 1250 | /* |
1251 | * If we are not running as root, the user must have the same uid as | |
1252 | * the server. | |
1253 | */ | |
5260325f | 1254 | if (getuid() != 0 && pw->pw_uid != getuid()) |
1255 | packet_disconnect("Cannot change user when server not running as root."); | |
8efc0c15 | 1256 | |
5260325f | 1257 | debug("Attempting authentication for %.100s.", user); |
8efc0c15 | 1258 | |
5260325f | 1259 | /* If the user has no password, accept authentication immediately. */ |
1260 | if (options.password_authentication && | |
8efc0c15 | 1261 | #ifdef KRB4 |
5260325f | 1262 | (!options.kerberos_authentication || options.kerberos_or_local_passwd) && |
8efc0c15 | 1263 | #endif /* KRB4 */ |
5260325f | 1264 | auth_password(pw, "")) { |
1265 | /* Authentication with empty password succeeded. */ | |
1266 | log("Login for user %s from %.100s, accepted without authentication.", | |
1267 | pw->pw_name, get_remote_ipaddr()); | |
1268 | } else { | |
1269 | /* Loop until the user has been authenticated or the | |
1270 | connection is closed, do_authloop() returns only if | |
1271 | authentication is successfull */ | |
1272 | do_authloop(pw); | |
1273 | } | |
1274 | ||
1275 | /* Check if the user is logging in as root and root logins are disallowed. */ | |
1276 | if (pw->pw_uid == 0 && !options.permit_root_login) { | |
1277 | if (forced_command) | |
1278 | log("Root login accepted for forced command."); | |
1279 | else | |
1280 | packet_disconnect("ROOT LOGIN REFUSED FROM %.200s", | |
1281 | get_canonical_hostname()); | |
1282 | } | |
1283 | /* The user has been authenticated and accepted. */ | |
1284 | packet_start(SSH_SMSG_SUCCESS); | |
1285 | packet_send(); | |
1286 | packet_write_wait(); | |
1287 | ||
1288 | /* Perform session preparation. */ | |
1289 | do_authenticated(pw); | |
e7c0f9d5 | 1290 | } |
8efc0c15 | 1291 | |
5260325f | 1292 | #define AUTH_FAIL_MAX 6 |
1293 | #define AUTH_FAIL_LOG (AUTH_FAIL_MAX/2) | |
1294 | #define AUTH_FAIL_MSG "Too many authentication failures for %.100s" | |
e7c0f9d5 | 1295 | |
5260325f | 1296 | /* |
1297 | * read packets and try to authenticate local user *pw. | |
1298 | * return if authentication is successfull | |
1299 | */ | |
e7c0f9d5 | 1300 | void |
5260325f | 1301 | do_authloop(struct passwd * pw) |
e7c0f9d5 | 1302 | { |
5260325f | 1303 | int attempt = 0; |
1304 | unsigned int bits; | |
1305 | BIGNUM *client_host_key_e, *client_host_key_n; | |
1306 | BIGNUM *n; | |
1307 | char *client_user = NULL, *password = NULL; | |
1308 | char user[1024]; | |
1309 | int plen, dlen, nlen, ulen, elen; | |
1310 | int type = 0; | |
1311 | void (*authlog) (const char *fmt,...) = verbose; | |
c75a1a66 | 1312 | #ifdef HAVE_LIBPAM |
5260325f | 1313 | int pam_retval; |
c75a1a66 | 1314 | #endif /* HAVE_LIBPAM */ |
e7c0f9d5 | 1315 | |
5260325f | 1316 | /* Indicate that authentication is needed. */ |
1317 | packet_start(SSH_SMSG_FAILURE); | |
1318 | packet_send(); | |
1319 | packet_write_wait(); | |
e7c0f9d5 | 1320 | |
5260325f | 1321 | for (attempt = 1;; attempt++) { |
1322 | int authenticated = 0; | |
1323 | strlcpy(user, "", sizeof user); | |
e7c0f9d5 | 1324 | |
5260325f | 1325 | /* Get a packet from the client. */ |
1326 | type = packet_read(&plen); | |
1327 | ||
1328 | /* Process the packet. */ | |
1329 | switch (type) { | |
e7c0f9d5 | 1330 | #ifdef AFS |
5260325f | 1331 | case SSH_CMSG_HAVE_KERBEROS_TGT: |
1332 | if (!options.kerberos_tgt_passing) { | |
1333 | /* packet_get_all(); */ | |
1334 | verbose("Kerberos tgt passing disabled."); | |
1335 | break; | |
1336 | } else { | |
1337 | /* Accept Kerberos tgt. */ | |
1338 | char *tgt = packet_get_string(&dlen); | |
1339 | packet_integrity_check(plen, 4 + dlen, type); | |
1340 | if (!auth_kerberos_tgt(pw, tgt)) | |
1341 | verbose("Kerberos tgt REFUSED for %s", pw->pw_name); | |
1342 | xfree(tgt); | |
1343 | } | |
1344 | continue; | |
1345 | ||
1346 | case SSH_CMSG_HAVE_AFS_TOKEN: | |
1347 | if (!options.afs_token_passing || !k_hasafs()) { | |
1348 | /* packet_get_all(); */ | |
1349 | verbose("AFS token passing disabled."); | |
1350 | break; | |
1351 | } else { | |
1352 | /* Accept AFS token. */ | |
1353 | char *token_string = packet_get_string(&dlen); | |
1354 | packet_integrity_check(plen, 4 + dlen, type); | |
1355 | if (!auth_afs_token(pw, token_string)) | |
1356 | verbose("AFS token REFUSED for %s", pw->pw_name); | |
1357 | xfree(token_string); | |
1358 | } | |
1359 | continue; | |
8efc0c15 | 1360 | #endif /* AFS */ |
e7c0f9d5 | 1361 | #ifdef KRB4 |
5260325f | 1362 | case SSH_CMSG_AUTH_KERBEROS: |
1363 | if (!options.kerberos_authentication) { | |
1364 | /* packet_get_all(); */ | |
1365 | verbose("Kerberos authentication disabled."); | |
1366 | break; | |
1367 | } else { | |
1368 | /* Try Kerberos v4 authentication. */ | |
1369 | KTEXT_ST auth; | |
1370 | char *tkt_user = NULL; | |
1371 | char *kdata = packet_get_string((unsigned int *) &auth.length); | |
1372 | packet_integrity_check(plen, 4 + auth.length, type); | |
1373 | ||
1374 | if (auth.length < MAX_KTXT_LEN) | |
1375 | memcpy(auth.dat, kdata, auth.length); | |
1376 | xfree(kdata); | |
1377 | ||
1378 | authenticated = auth_krb4(pw->pw_name, &auth, &tkt_user); | |
1379 | ||
1380 | if (authenticated) { | |
1381 | snprintf(user, sizeof user, " tktuser %s", tkt_user); | |
1382 | xfree(tkt_user); | |
1383 | } | |
1384 | } | |
1385 | break; | |
e7c0f9d5 | 1386 | #endif /* KRB4 */ |
5260325f | 1387 | |
1388 | case SSH_CMSG_AUTH_RHOSTS: | |
1389 | if (!options.rhosts_authentication) { | |
1390 | verbose("Rhosts authentication disabled."); | |
1391 | break; | |
1392 | } | |
aa3378df | 1393 | /* |
1394 | * Get client user name. Note that we just have to | |
1395 | * trust the client; this is one reason why rhosts | |
1396 | * authentication is insecure. (Another is | |
1397 | * IP-spoofing on a local network.) | |
1398 | */ | |
5260325f | 1399 | client_user = packet_get_string(&ulen); |
1400 | packet_integrity_check(plen, 4 + ulen, type); | |
1401 | ||
1402 | /* Try to authenticate using /etc/hosts.equiv and | |
1403 | .rhosts. */ | |
1404 | authenticated = auth_rhosts(pw, client_user); | |
1405 | ||
1406 | snprintf(user, sizeof user, " ruser %s", client_user); | |
5aecb327 | 1407 | #ifndef HAVE_LIBPAM |
5260325f | 1408 | xfree(client_user); |
5aecb327 | 1409 | #endif /* HAVE_LIBPAM */ |
5260325f | 1410 | break; |
1411 | ||
1412 | case SSH_CMSG_AUTH_RHOSTS_RSA: | |
1413 | if (!options.rhosts_rsa_authentication) { | |
1414 | verbose("Rhosts with RSA authentication disabled."); | |
1415 | break; | |
1416 | } | |
aa3378df | 1417 | /* |
1418 | * Get client user name. Note that we just have to | |
1419 | * trust the client; root on the client machine can | |
1420 | * claim to be any user. | |
1421 | */ | |
5260325f | 1422 | client_user = packet_get_string(&ulen); |
1423 | ||
1424 | /* Get the client host key. */ | |
1425 | client_host_key_e = BN_new(); | |
1426 | client_host_key_n = BN_new(); | |
1427 | bits = packet_get_int(); | |
1428 | packet_get_bignum(client_host_key_e, &elen); | |
1429 | packet_get_bignum(client_host_key_n, &nlen); | |
1430 | ||
1431 | if (bits != BN_num_bits(client_host_key_n)) | |
1432 | error("Warning: keysize mismatch for client_host_key: " | |
1433 | "actual %d, announced %d", BN_num_bits(client_host_key_n), bits); | |
1434 | packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type); | |
1435 | ||
1436 | authenticated = auth_rhosts_rsa(pw, client_user, | |
1437 | client_host_key_e, client_host_key_n); | |
1438 | BN_clear_free(client_host_key_e); | |
1439 | BN_clear_free(client_host_key_n); | |
1440 | ||
1441 | snprintf(user, sizeof user, " ruser %s", client_user); | |
5aecb327 | 1442 | #ifndef HAVE_LIBPAM |
5260325f | 1443 | xfree(client_user); |
5aecb327 | 1444 | #endif /* HAVE_LIBPAM */ |
5260325f | 1445 | break; |
1446 | ||
1447 | case SSH_CMSG_AUTH_RSA: | |
1448 | if (!options.rsa_authentication) { | |
1449 | verbose("RSA authentication disabled."); | |
1450 | break; | |
1451 | } | |
1452 | /* RSA authentication requested. */ | |
1453 | n = BN_new(); | |
1454 | packet_get_bignum(n, &nlen); | |
1455 | packet_integrity_check(plen, nlen, type); | |
1456 | authenticated = auth_rsa(pw, n); | |
1457 | BN_clear_free(n); | |
1458 | break; | |
1459 | ||
1460 | case SSH_CMSG_AUTH_PASSWORD: | |
1461 | if (!options.password_authentication) { | |
1462 | verbose("Password authentication disabled."); | |
1463 | break; | |
1464 | } | |
aa3378df | 1465 | /* |
1466 | * Read user password. It is in plain text, but was | |
1467 | * transmitted over the encrypted channel so it is | |
1468 | * not visible to an outside observer. | |
1469 | */ | |
5260325f | 1470 | password = packet_get_string(&dlen); |
1471 | packet_integrity_check(plen, 4 + dlen, type); | |
1472 | ||
5aecb327 | 1473 | #ifdef HAVE_LIBPAM |
5260325f | 1474 | /* Do PAM auth with password */ |
1475 | pampasswd = password; | |
1476 | pam_retval = pam_authenticate((pam_handle_t *)pamh, 0); | |
1477 | if (pam_retval == PAM_SUCCESS) { | |
1478 | log("PAM Password authentication accepted for user \"%.100s\"", pw->pw_name); | |
1479 | authenticated = 1; | |
1480 | break; | |
1481 | } | |
1482 | ||
1483 | log("PAM Password authentication for \"%.100s\" failed: %s", | |
1484 | pw->pw_name, PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); | |
1485 | break; | |
5aecb327 | 1486 | #else /* HAVE_LIBPAM */ |
5260325f | 1487 | /* Try authentication with the password. */ |
1488 | authenticated = auth_password(pw, password); | |
1489 | ||
1490 | memset(password, 0, strlen(password)); | |
1491 | xfree(password); | |
1492 | break; | |
e7c0f9d5 | 1493 | #endif /* HAVE_LIBPAM */ |
5260325f | 1494 | |
1495 | #ifdef SKEY | |
1496 | case SSH_CMSG_AUTH_TIS: | |
1497 | debug("rcvd SSH_CMSG_AUTH_TIS"); | |
1498 | if (options.skey_authentication == 1) { | |
1499 | char *skeyinfo = skey_keyinfo(pw->pw_name); | |
1500 | if (skeyinfo == NULL) { | |
1501 | debug("generating fake skeyinfo for %.100s.", pw->pw_name); | |
1502 | skeyinfo = skey_fake_keyinfo(pw->pw_name); | |
1503 | } | |
1504 | if (skeyinfo != NULL) { | |
aa3378df | 1505 | /* we send our s/key- in tis-challenge messages */ |
5260325f | 1506 | debug("sending challenge '%s'", skeyinfo); |
1507 | packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE); | |
1508 | packet_put_string(skeyinfo, strlen(skeyinfo)); | |
1509 | packet_send(); | |
1510 | packet_write_wait(); | |
1511 | continue; | |
1512 | } | |
1513 | } | |
1514 | break; | |
1515 | case SSH_CMSG_AUTH_TIS_RESPONSE: | |
1516 | debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE"); | |
1517 | if (options.skey_authentication == 1) { | |
1518 | char *response = packet_get_string(&dlen); | |
1519 | debug("skey response == '%s'", response); | |
1520 | packet_integrity_check(plen, 4 + dlen, type); | |
1521 | authenticated = (skey_haskey(pw->pw_name) == 0 && | |
1522 | skey_passcheck(pw->pw_name, response) != -1); | |
1523 | xfree(response); | |
1524 | } | |
1525 | break; | |
1526 | #else | |
1527 | case SSH_CMSG_AUTH_TIS: | |
1528 | /* TIS Authentication is unsupported */ | |
1529 | log("TIS authentication unsupported."); | |
1530 | break; | |
1531 | #endif | |
1532 | ||
1533 | default: | |
aa3378df | 1534 | /* |
1535 | * Any unknown messages will be ignored (and failure | |
1536 | * returned) during authentication. | |
1537 | */ | |
5260325f | 1538 | log("Unknown message during authentication: type %d", type); |
1539 | break; | |
1540 | } | |
1541 | ||
1542 | /* Raise logging level */ | |
1543 | if (authenticated || | |
1544 | attempt == AUTH_FAIL_LOG || | |
1545 | type == SSH_CMSG_AUTH_PASSWORD) | |
1546 | authlog = log; | |
1547 | ||
1548 | authlog("%s %s for %.200s from %.200s port %d%s", | |
1549 | authenticated ? "Accepted" : "Failed", | |
1550 | get_authname(type), | |
1551 | pw->pw_uid == 0 ? "ROOT" : pw->pw_name, | |
1552 | get_remote_ipaddr(), | |
1553 | get_remote_port(), | |
1554 | user); | |
8efc0c15 | 1555 | |
d465f2ca | 1556 | #ifndef HAVE_LIBPAM |
1557 | if (authenticated) | |
1558 | return; | |
d813bc69 | 1559 | |
d465f2ca | 1560 | if (attempt > AUTH_FAIL_MAX) |
1561 | packet_disconnect(AUTH_FAIL_MSG, pw->pw_name); | |
1562 | #else /* HAVE_LIBPAM */ | |
1563 | if (authenticated) { | |
1564 | do_pam_account_and_session(pw->pw_name, client_user); | |
d813bc69 | 1565 | |
d465f2ca | 1566 | /* Clean up */ |
1567 | if (client_user != NULL) | |
1568 | xfree(client_user); | |
5260325f | 1569 | |
d465f2ca | 1570 | if (password != NULL) { |
1571 | memset(password, 0, strlen(password)); | |
1572 | xfree(password); | |
1573 | } | |
1574 | ||
5260325f | 1575 | return; |
d465f2ca | 1576 | } |
5260325f | 1577 | |
d465f2ca | 1578 | if (attempt > AUTH_FAIL_MAX) { |
1579 | /* Clean up */ | |
1580 | if (client_user != NULL) | |
1581 | xfree(client_user); | |
1582 | ||
1583 | if (password != NULL) { | |
1584 | memset(password, 0, strlen(password)); | |
1585 | xfree(password); | |
1586 | } | |
1587 | ||
5260325f | 1588 | packet_disconnect(AUTH_FAIL_MSG, pw->pw_name); |
d465f2ca | 1589 | } |
1590 | #endif /* HAVE_LIBPAM */ | |
5260325f | 1591 | |
1592 | /* Send a message indicating that the authentication attempt failed. */ | |
1593 | packet_start(SSH_SMSG_FAILURE); | |
1594 | packet_send(); | |
1595 | packet_write_wait(); | |
1596 | } | |
8efc0c15 | 1597 | } |
1598 | ||
5260325f | 1599 | /* |
1600 | * The user does not exist or access is denied, | |
1601 | * but fake indication that authentication is needed. | |
1602 | */ | |
e7c0f9d5 | 1603 | void |
1604 | do_fake_authloop(char *user) | |
0183ea1c | 1605 | { |
5260325f | 1606 | int attempt = 0; |
1607 | ||
1608 | log("Faking authloop for illegal user %.200s from %.200s port %d", | |
1609 | user, | |
1610 | get_remote_ipaddr(), | |
1611 | get_remote_port()); | |
1612 | ||
1613 | /* Indicate that authentication is needed. */ | |
1614 | packet_start(SSH_SMSG_FAILURE); | |
1615 | packet_send(); | |
1616 | packet_write_wait(); | |
1617 | ||
aa3378df | 1618 | /* |
1619 | * Keep reading packets, and always respond with a failure. This is | |
1620 | * to avoid disclosing whether such a user really exists. | |
1621 | */ | |
5260325f | 1622 | for (attempt = 1;; attempt++) { |
aa3378df | 1623 | /* Read a packet. This will not return if the client disconnects. */ |
5260325f | 1624 | int plen; |
1625 | int type = packet_read(&plen); | |
e7c0f9d5 | 1626 | #ifdef SKEY |
5260325f | 1627 | int dlen; |
1628 | char *password, *skeyinfo; | |
1629 | if (options.password_authentication && | |
1630 | options.skey_authentication == 1 && | |
1631 | type == SSH_CMSG_AUTH_PASSWORD && | |
1632 | (password = packet_get_string(&dlen)) != NULL && | |
1633 | dlen == 5 && | |
1634 | strncasecmp(password, "s/key", 5) == 0 && | |
1635 | (skeyinfo = skey_fake_keyinfo(user)) != NULL) { | |
1636 | /* Send a fake s/key challenge. */ | |
1637 | packet_send_debug(skeyinfo); | |
1638 | } | |
e7c0f9d5 | 1639 | #endif |
5260325f | 1640 | if (attempt > AUTH_FAIL_MAX) |
1641 | packet_disconnect(AUTH_FAIL_MSG, user); | |
1642 | ||
aa3378df | 1643 | /* |
1644 | * Send failure. This should be indistinguishable from a | |
1645 | * failed authentication. | |
1646 | */ | |
5260325f | 1647 | packet_start(SSH_SMSG_FAILURE); |
1648 | packet_send(); | |
1649 | packet_write_wait(); | |
1650 | } | |
1651 | /* NOTREACHED */ | |
1652 | abort(); | |
0183ea1c | 1653 | } |
1654 | ||
e7c0f9d5 | 1655 | |
5260325f | 1656 | /* |
1657 | * Remove local Xauthority file. | |
1658 | */ | |
6a17f9c2 | 1659 | static void |
1660 | xauthfile_cleanup_proc(void *ignore) | |
1661 | { | |
5260325f | 1662 | debug("xauthfile_cleanup_proc called"); |
6a17f9c2 | 1663 | |
5260325f | 1664 | if (xauthfile != NULL) { |
1665 | unlink(xauthfile); | |
1666 | xfree(xauthfile); | |
1667 | xauthfile = NULL; | |
1668 | } | |
6a17f9c2 | 1669 | } |
1670 | ||
5260325f | 1671 | /* |
1672 | * Prepares for an interactive session. This is called after the user has | |
1673 | * been successfully authenticated. During this message exchange, pseudo | |
1674 | * terminals are allocated, X11, TCP/IP, and authentication agent forwardings | |
1675 | * are requested, etc. | |
1676 | */ | |
1677 | void | |
1678 | do_authenticated(struct passwd * pw) | |
8efc0c15 | 1679 | { |
5260325f | 1680 | int type; |
1681 | int compression_level = 0, enable_compression_after_reply = 0; | |
1682 | int have_pty = 0, ptyfd = -1, ttyfd = -1, xauthfd = -1; | |
1683 | int row, col, xpixel, ypixel, screen; | |
1684 | char ttyname[64]; | |
1685 | char *command, *term = NULL, *display = NULL, *proto = NULL, | |
1686 | *data = NULL; | |
1687 | struct group *grp; | |
1688 | gid_t tty_gid; | |
1689 | mode_t tty_mode; | |
1690 | int n_bytes; | |
1691 | ||
aa3378df | 1692 | /* |
1693 | * Cancel the alarm we set to limit the time taken for | |
1694 | * authentication. | |
1695 | */ | |
5260325f | 1696 | alarm(0); |
1697 | ||
aa3378df | 1698 | /* |
1699 | * Inform the channel mechanism that we are the server side and that | |
1700 | * the client may request to connect to any port at all. (The user | |
1701 | * could do it anyway, and we wouldn\'t know what is permitted except | |
1702 | * by the client telling us, so we can equally well trust the client | |
1703 | * not to request anything bogus.) | |
1704 | */ | |
5260325f | 1705 | channel_permit_all_opens(); |
1706 | ||
aa3378df | 1707 | /* |
1708 | * We stay in this loop until the client requests to execute a shell | |
1709 | * or a command. | |
1710 | */ | |
5260325f | 1711 | while (1) { |
1712 | int plen, dlen; | |
1713 | ||
1714 | /* Get a packet from the client. */ | |
1715 | type = packet_read(&plen); | |
1716 | ||
1717 | /* Process the packet. */ | |
1718 | switch (type) { | |
1719 | case SSH_CMSG_REQUEST_COMPRESSION: | |
1720 | packet_integrity_check(plen, 4, type); | |
1721 | compression_level = packet_get_int(); | |
1722 | if (compression_level < 1 || compression_level > 9) { | |
1723 | packet_send_debug("Received illegal compression level %d.", | |
1724 | compression_level); | |
1725 | goto fail; | |
1726 | } | |
1727 | /* Enable compression after we have responded with SUCCESS. */ | |
1728 | enable_compression_after_reply = 1; | |
1729 | break; | |
1730 | ||
1731 | case SSH_CMSG_REQUEST_PTY: | |
1732 | if (no_pty_flag) { | |
1733 | debug("Allocating a pty not permitted for this authentication."); | |
1734 | goto fail; | |
1735 | } | |
1736 | if (have_pty) | |
1737 | packet_disconnect("Protocol error: you already have a pty."); | |
1738 | ||
1739 | debug("Allocating pty."); | |
1740 | ||
1741 | /* Allocate a pty and open it. */ | |
a408af76 | 1742 | if (!pty_allocate(&ptyfd, &ttyfd, ttyname, |
1743 | sizeof(ttyname))) { | |
5260325f | 1744 | error("Failed to allocate pty."); |
1745 | goto fail; | |
1746 | } | |
1747 | /* Determine the group to make the owner of the tty. */ | |
1748 | grp = getgrnam("tty"); | |
1749 | if (grp) { | |
1750 | tty_gid = grp->gr_gid; | |
1751 | tty_mode = S_IRUSR | S_IWUSR | S_IWGRP; | |
1752 | } else { | |
1753 | tty_gid = pw->pw_gid; | |
1754 | tty_mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH; | |
1755 | } | |
1756 | ||
1757 | /* Change ownership of the tty. */ | |
1758 | if (chown(ttyname, pw->pw_uid, tty_gid) < 0) | |
1759 | fatal("chown(%.100s, %d, %d) failed: %.100s", | |
1760 | ttyname, pw->pw_uid, tty_gid, strerror(errno)); | |
1761 | if (chmod(ttyname, tty_mode) < 0) | |
1762 | fatal("chmod(%.100s, 0%o) failed: %.100s", | |
1763 | ttyname, tty_mode, strerror(errno)); | |
1764 | ||
1765 | /* Get TERM from the packet. Note that the value may be of arbitrary length. */ | |
1766 | term = packet_get_string(&dlen); | |
1767 | packet_integrity_check(dlen, strlen(term), type); | |
1768 | /* packet_integrity_check(plen, 4 + dlen + 4*4 + n_bytes, type); */ | |
1769 | /* Remaining bytes */ | |
1770 | n_bytes = plen - (4 + dlen + 4 * 4); | |
1771 | ||
1772 | if (strcmp(term, "") == 0) | |
1773 | term = NULL; | |
1774 | ||
1775 | /* Get window size from the packet. */ | |
1776 | row = packet_get_int(); | |
1777 | col = packet_get_int(); | |
1778 | xpixel = packet_get_int(); | |
1779 | ypixel = packet_get_int(); | |
1780 | pty_change_window_size(ptyfd, row, col, xpixel, ypixel); | |
1781 | ||
1782 | /* Get tty modes from the packet. */ | |
1783 | tty_parse_modes(ttyfd, &n_bytes); | |
1784 | packet_integrity_check(plen, 4 + dlen + 4 * 4 + n_bytes, type); | |
1785 | ||
1786 | /* Indicate that we now have a pty. */ | |
1787 | have_pty = 1; | |
1788 | break; | |
1789 | ||
1790 | case SSH_CMSG_X11_REQUEST_FORWARDING: | |
1791 | if (!options.x11_forwarding) { | |
1792 | packet_send_debug("X11 forwarding disabled in server configuration file."); | |
1793 | goto fail; | |
1794 | } | |
8efc0c15 | 1795 | #ifdef XAUTH_PATH |
5260325f | 1796 | if (no_x11_forwarding_flag) { |
1797 | packet_send_debug("X11 forwarding not permitted for this authentication."); | |
1798 | goto fail; | |
1799 | } | |
1800 | debug("Received request for X11 forwarding with auth spoofing."); | |
1801 | if (display) | |
1802 | packet_disconnect("Protocol error: X11 display already set."); | |
1803 | { | |
1804 | int proto_len, data_len; | |
1805 | proto = packet_get_string(&proto_len); | |
1806 | data = packet_get_string(&data_len); | |
1807 | packet_integrity_check(plen, 4 + proto_len + 4 + data_len + 4, type); | |
1808 | } | |
1809 | if (packet_get_protocol_flags() & SSH_PROTOFLAG_SCREEN_NUMBER) | |
1810 | screen = packet_get_int(); | |
1811 | else | |
1812 | screen = 0; | |
1813 | display = x11_create_display_inet(screen); | |
1814 | if (!display) | |
1815 | goto fail; | |
1816 | ||
1817 | /* Setup to always have a local .Xauthority. */ | |
1818 | xauthfile = xmalloc(MAXPATHLEN); | |
1819 | snprintf(xauthfile, MAXPATHLEN, "/tmp/XauthXXXXXX"); | |
1820 | ||
1821 | if ((xauthfd = mkstemp(xauthfile)) != -1) { | |
1822 | fchown(xauthfd, pw->pw_uid, pw->pw_gid); | |
1823 | close(xauthfd); | |
1824 | fatal_add_cleanup(xauthfile_cleanup_proc, NULL); | |
1825 | } else { | |
1826 | xfree(xauthfile); | |
1827 | xauthfile = NULL; | |
1828 | } | |
1829 | break; | |
8efc0c15 | 1830 | #else /* XAUTH_PATH */ |
5260325f | 1831 | packet_send_debug("No xauth program; cannot forward with spoofing."); |
1832 | goto fail; | |
8efc0c15 | 1833 | #endif /* XAUTH_PATH */ |
1834 | ||
5260325f | 1835 | case SSH_CMSG_AGENT_REQUEST_FORWARDING: |
1836 | if (no_agent_forwarding_flag) { | |
1837 | debug("Authentication agent forwarding not permitted for this authentication."); | |
1838 | goto fail; | |
1839 | } | |
1840 | debug("Received authentication agent forwarding request."); | |
1841 | auth_input_request_forwarding(pw); | |
1842 | break; | |
1843 | ||
1844 | case SSH_CMSG_PORT_FORWARD_REQUEST: | |
1845 | if (no_port_forwarding_flag) { | |
1846 | debug("Port forwarding not permitted for this authentication."); | |
1847 | goto fail; | |
1848 | } | |
1849 | debug("Received TCP/IP port forwarding request."); | |
1850 | channel_input_port_forward_request(pw->pw_uid == 0); | |
1851 | break; | |
1852 | ||
1853 | case SSH_CMSG_MAX_PACKET_SIZE: | |
1854 | if (packet_set_maxsize(packet_get_int()) < 0) | |
1855 | goto fail; | |
1856 | break; | |
1857 | ||
1858 | case SSH_CMSG_EXEC_SHELL: | |
1859 | /* Set interactive/non-interactive mode. */ | |
1860 | packet_set_interactive(have_pty || display != NULL, | |
1861 | options.keepalives); | |
1862 | ||
1863 | if (forced_command != NULL) | |
1864 | goto do_forced_command; | |
1865 | debug("Forking shell."); | |
1866 | packet_integrity_check(plen, 0, type); | |
1867 | if (have_pty) | |
1868 | do_exec_pty(NULL, ptyfd, ttyfd, ttyname, pw, term, display, proto, data); | |
1869 | else | |
1870 | do_exec_no_pty(NULL, pw, display, proto, data); | |
1871 | return; | |
1872 | ||
1873 | case SSH_CMSG_EXEC_CMD: | |
1874 | /* Set interactive/non-interactive mode. */ | |
1875 | packet_set_interactive(have_pty || display != NULL, | |
1876 | options.keepalives); | |
1877 | ||
1878 | if (forced_command != NULL) | |
1879 | goto do_forced_command; | |
1880 | /* Get command from the packet. */ | |
1881 | { | |
1882 | int dlen; | |
1883 | command = packet_get_string(&dlen); | |
1884 | debug("Executing command '%.500s'", command); | |
1885 | packet_integrity_check(plen, 4 + dlen, type); | |
1886 | } | |
1887 | if (have_pty) | |
1888 | do_exec_pty(command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data); | |
1889 | else | |
1890 | do_exec_no_pty(command, pw, display, proto, data); | |
1891 | xfree(command); | |
1892 | return; | |
1893 | ||
1894 | default: | |
aa3378df | 1895 | /* |
1896 | * Any unknown messages in this phase are ignored, | |
1897 | * and a failure message is returned. | |
1898 | */ | |
5260325f | 1899 | log("Unknown packet type received after authentication: %d", type); |
1900 | goto fail; | |
1901 | } | |
8efc0c15 | 1902 | |
5260325f | 1903 | /* The request was successfully processed. */ |
1904 | packet_start(SSH_SMSG_SUCCESS); | |
1905 | packet_send(); | |
1906 | packet_write_wait(); | |
8efc0c15 | 1907 | |
5260325f | 1908 | /* Enable compression now that we have replied if appropriate. */ |
1909 | if (enable_compression_after_reply) { | |
1910 | enable_compression_after_reply = 0; | |
1911 | packet_start_compression(compression_level); | |
1912 | } | |
1913 | continue; | |
8efc0c15 | 1914 | |
5260325f | 1915 | fail: |
1916 | /* The request failed. */ | |
1917 | packet_start(SSH_SMSG_FAILURE); | |
1918 | packet_send(); | |
1919 | packet_write_wait(); | |
1920 | continue; | |
8efc0c15 | 1921 | |
5260325f | 1922 | do_forced_command: |
aa3378df | 1923 | /* |
1924 | * There is a forced command specified for this login. | |
1925 | * Execute it. | |
1926 | */ | |
5260325f | 1927 | debug("Executing forced command: %.900s", forced_command); |
1928 | if (have_pty) | |
1929 | do_exec_pty(forced_command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data); | |
1930 | else | |
1931 | do_exec_no_pty(forced_command, pw, display, proto, data); | |
1932 | return; | |
1933 | } | |
1934 | } | |
8efc0c15 | 1935 | |
5260325f | 1936 | /* |
1937 | * This is called to fork and execute a command when we have no tty. This | |
1938 | * will call do_child from the child, and server_loop from the parent after | |
1939 | * setting up file descriptors and such. | |
1940 | */ | |
1941 | void | |
1942 | do_exec_no_pty(const char *command, struct passwd * pw, | |
1943 | const char *display, const char *auth_proto, | |
1944 | const char *auth_data) | |
1945 | { | |
1946 | int pid; | |
8efc0c15 | 1947 | |
1948 | #ifdef USE_PIPES | |
5260325f | 1949 | int pin[2], pout[2], perr[2]; |
1950 | /* Allocate pipes for communicating with the program. */ | |
1951 | if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0) | |
1952 | packet_disconnect("Could not create pipes: %.100s", | |
1953 | strerror(errno)); | |
8efc0c15 | 1954 | #else /* USE_PIPES */ |
5260325f | 1955 | int inout[2], err[2]; |
1956 | /* Uses socket pairs to communicate with the program. */ | |
1957 | if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 || | |
1958 | socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) | |
1959 | packet_disconnect("Could not create socket pairs: %.100s", | |
1960 | strerror(errno)); | |
8efc0c15 | 1961 | #endif /* USE_PIPES */ |
8efc0c15 | 1962 | |
5260325f | 1963 | setproctitle("%s@notty", pw->pw_name); |
8efc0c15 | 1964 | |
5260325f | 1965 | /* Fork the child. */ |
1966 | if ((pid = fork()) == 0) { | |
1967 | /* Child. Reinitialize the log since the pid has changed. */ | |
1968 | log_init(av0, options.log_level, options.log_facility, log_stderr); | |
1969 | ||
aa3378df | 1970 | /* |
1971 | * Create a new session and process group since the 4.4BSD | |
1972 | * setlogin() affects the entire process group. | |
1973 | */ | |
5260325f | 1974 | if (setsid() < 0) |
1975 | error("setsid failed: %.100s", strerror(errno)); | |
8efc0c15 | 1976 | |
1977 | #ifdef USE_PIPES | |
aa3378df | 1978 | /* |
1979 | * Redirect stdin. We close the parent side of the socket | |
1980 | * pair, and make the child side the standard input. | |
1981 | */ | |
5260325f | 1982 | close(pin[1]); |
1983 | if (dup2(pin[0], 0) < 0) | |
1984 | perror("dup2 stdin"); | |
1985 | close(pin[0]); | |
1986 | ||
1987 | /* Redirect stdout. */ | |
1988 | close(pout[0]); | |
1989 | if (dup2(pout[1], 1) < 0) | |
1990 | perror("dup2 stdout"); | |
1991 | close(pout[1]); | |
1992 | ||
1993 | /* Redirect stderr. */ | |
1994 | close(perr[0]); | |
1995 | if (dup2(perr[1], 2) < 0) | |
1996 | perror("dup2 stderr"); | |
1997 | close(perr[1]); | |
8efc0c15 | 1998 | #else /* USE_PIPES */ |
aa3378df | 1999 | /* |
2000 | * Redirect stdin, stdout, and stderr. Stdin and stdout will | |
2001 | * use the same socket, as some programs (particularly rdist) | |
2002 | * seem to depend on it. | |
2003 | */ | |
5260325f | 2004 | close(inout[1]); |
2005 | close(err[1]); | |
2006 | if (dup2(inout[0], 0) < 0) /* stdin */ | |
2007 | perror("dup2 stdin"); | |
2008 | if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */ | |
2009 | perror("dup2 stdout"); | |
2010 | if (dup2(err[0], 2) < 0) /* stderr */ | |
2011 | perror("dup2 stderr"); | |
8efc0c15 | 2012 | #endif /* USE_PIPES */ |
2013 | ||
5260325f | 2014 | /* Do processing for the child (exec command etc). */ |
2015 | do_child(command, pw, NULL, display, auth_proto, auth_data, NULL); | |
2016 | /* NOTREACHED */ | |
2017 | } | |
2018 | if (pid < 0) | |
2019 | packet_disconnect("fork failed: %.100s", strerror(errno)); | |
8efc0c15 | 2020 | #ifdef USE_PIPES |
5260325f | 2021 | /* We are the parent. Close the child sides of the pipes. */ |
2022 | close(pin[0]); | |
2023 | close(pout[1]); | |
2024 | close(perr[1]); | |
2025 | ||
2026 | /* Enter the interactive session. */ | |
2027 | server_loop(pid, pin[1], pout[0], perr[0]); | |
2028 | /* server_loop has closed pin[1], pout[1], and perr[1]. */ | |
8efc0c15 | 2029 | #else /* USE_PIPES */ |
5260325f | 2030 | /* We are the parent. Close the child sides of the socket pairs. */ |
2031 | close(inout[0]); | |
2032 | close(err[0]); | |
2033 | ||
aa3378df | 2034 | /* |
2035 | * Enter the interactive session. Note: server_loop must be able to | |
2036 | * handle the case that fdin and fdout are the same. | |
2037 | */ | |
5260325f | 2038 | server_loop(pid, inout[1], inout[1], err[1]); |
2039 | /* server_loop has closed inout[1] and err[1]. */ | |
8efc0c15 | 2040 | #endif /* USE_PIPES */ |
2041 | } | |
2042 | ||
5260325f | 2043 | struct pty_cleanup_context { |
2044 | const char *ttyname; | |
2045 | int pid; | |
8efc0c15 | 2046 | }; |
2047 | ||
5260325f | 2048 | /* |
2049 | * Function to perform cleanup if we get aborted abnormally (e.g., due to a | |
2050 | * dropped connection). | |
2051 | */ | |
2052 | void | |
2053 | pty_cleanup_proc(void *context) | |
8efc0c15 | 2054 | { |
5260325f | 2055 | struct pty_cleanup_context *cu = context; |
8efc0c15 | 2056 | |
5260325f | 2057 | debug("pty_cleanup_proc called"); |
8efc0c15 | 2058 | |
5260325f | 2059 | /* Record that the user has logged out. */ |
2060 | record_logout(cu->pid, cu->ttyname); | |
8efc0c15 | 2061 | |
5260325f | 2062 | /* Release the pseudo-tty. */ |
2063 | pty_release(cu->ttyname); | |
8efc0c15 | 2064 | } |
2065 | ||
5260325f | 2066 | /* |
2067 | * This is called to fork and execute a command when we have a tty. This | |
2068 | * will call do_child from the child, and server_loop from the parent after | |
2069 | * setting up file descriptors, controlling tty, updating wtmp, utmp, | |
2070 | * lastlog, and other such operations. | |
2071 | */ | |
2072 | void | |
2073 | do_exec_pty(const char *command, int ptyfd, int ttyfd, | |
2074 | const char *ttyname, struct passwd * pw, const char *term, | |
2075 | const char *display, const char *auth_proto, | |
2076 | const char *auth_data) | |
8efc0c15 | 2077 | { |
5260325f | 2078 | int pid, fdout; |
2079 | const char *hostname; | |
2080 | time_t last_login_time; | |
2081 | char buf[100], *time_string; | |
2082 | FILE *f; | |
2083 | char line[256]; | |
2084 | struct stat st; | |
2085 | int quiet_login; | |
2086 | struct sockaddr_in from; | |
2087 | int fromlen; | |
2088 | struct pty_cleanup_context cleanup_context; | |
2089 | ||
2090 | /* Get remote host name. */ | |
2091 | hostname = get_canonical_hostname(); | |
2092 | ||
aa3378df | 2093 | /* |
2094 | * Get the time when the user last logged in. Buf will be set to | |
2095 | * contain the hostname the last login was from. | |
2096 | */ | |
5260325f | 2097 | if (!options.use_login) { |
2098 | last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name, | |
2099 | buf, sizeof(buf)); | |
8efc0c15 | 2100 | } |
5260325f | 2101 | setproctitle("%s@%s", pw->pw_name, strrchr(ttyname, '/') + 1); |
2102 | ||
2103 | /* Fork the child. */ | |
2104 | if ((pid = fork()) == 0) { | |
2105 | pid = getpid(); | |
2106 | ||
2107 | /* Child. Reinitialize the log because the pid has | |
2108 | changed. */ | |
2109 | log_init(av0, options.log_level, options.log_facility, log_stderr); | |
2110 | ||
2111 | /* Close the master side of the pseudo tty. */ | |
2112 | close(ptyfd); | |
2113 | ||
2114 | /* Make the pseudo tty our controlling tty. */ | |
2115 | pty_make_controlling_tty(&ttyfd, ttyname); | |
2116 | ||
2117 | /* Redirect stdin from the pseudo tty. */ | |
2118 | if (dup2(ttyfd, fileno(stdin)) < 0) | |
2119 | error("dup2 stdin failed: %.100s", strerror(errno)); | |
2120 | ||
2121 | /* Redirect stdout to the pseudo tty. */ | |
2122 | if (dup2(ttyfd, fileno(stdout)) < 0) | |
2123 | error("dup2 stdin failed: %.100s", strerror(errno)); | |
2124 | ||
2125 | /* Redirect stderr to the pseudo tty. */ | |
2126 | if (dup2(ttyfd, fileno(stderr)) < 0) | |
2127 | error("dup2 stdin failed: %.100s", strerror(errno)); | |
2128 | ||
2129 | /* Close the extra descriptor for the pseudo tty. */ | |
2130 | close(ttyfd); | |
2131 | ||
aa3378df | 2132 | /* |
2133 | * Get IP address of client. This is needed because we want | |
2134 | * to record where the user logged in from. If the | |
2135 | * connection is not a socket, let the ip address be 0.0.0.0. | |
2136 | */ | |
5260325f | 2137 | memset(&from, 0, sizeof(from)); |
2138 | if (packet_get_connection_in() == packet_get_connection_out()) { | |
2139 | fromlen = sizeof(from); | |
2140 | if (getpeername(packet_get_connection_in(), | |
2141 | (struct sockaddr *) & from, &fromlen) < 0) { | |
2142 | debug("getpeername: %.100s", strerror(errno)); | |
2143 | fatal_cleanup(); | |
2144 | } | |
2145 | } | |
2146 | /* Record that there was a login on that terminal. */ | |
2147 | record_login(pid, ttyname, pw->pw_name, pw->pw_uid, hostname, | |
2148 | &from); | |
8efc0c15 | 2149 | |
5260325f | 2150 | /* Check if .hushlogin exists. */ |
2151 | snprintf(line, sizeof line, "%.200s/.hushlogin", pw->pw_dir); | |
2152 | quiet_login = stat(line, &st) >= 0; | |
e1a9c08d | 2153 | |
2154 | #ifdef HAVE_LIBPAM | |
5260325f | 2155 | /* output the results of the pamconv() */ |
2156 | if (!quiet_login && pamconv_msg != NULL) | |
2157 | fprintf(stderr, pamconv_msg); | |
e1a9c08d | 2158 | #endif |
8efc0c15 | 2159 | |
aa3378df | 2160 | /* |
2161 | * If the user has logged in before, display the time of last | |
2162 | * login. However, don't display anything extra if a command | |
2163 | * has been specified (so that ssh can be used to execute | |
2164 | * commands on a remote machine without users knowing they | |
2165 | * are going to another machine). Login(1) will do this for | |
2166 | * us as well, so check if login(1) is used | |
2167 | */ | |
5260325f | 2168 | if (command == NULL && last_login_time != 0 && !quiet_login && |
2169 | !options.use_login) { | |
2170 | /* Convert the date to a string. */ | |
2171 | time_string = ctime(&last_login_time); | |
2172 | /* Remove the trailing newline. */ | |
2173 | if (strchr(time_string, '\n')) | |
2174 | *strchr(time_string, '\n') = 0; | |
2175 | /* Display the last login time. Host if displayed | |
2176 | if known. */ | |
2177 | if (strcmp(buf, "") == 0) | |
2178 | printf("Last login: %s\r\n", time_string); | |
2179 | else | |
2180 | printf("Last login: %s from %s\r\n", time_string, buf); | |
2181 | } | |
aa3378df | 2182 | /* |
2183 | * Print /etc/motd unless a command was specified or printing | |
2184 | * it was disabled in server options or login(1) will be | |
2185 | * used. Note that some machines appear to print it in | |
2186 | * /etc/profile or similar. | |
2187 | */ | |
5260325f | 2188 | if (command == NULL && options.print_motd && !quiet_login && |
2189 | !options.use_login) { | |
2190 | /* Print /etc/motd if it exists. */ | |
2191 | f = fopen("/etc/motd", "r"); | |
2192 | if (f) { | |
2193 | while (fgets(line, sizeof(line), f)) | |
2194 | fputs(line, stdout); | |
2195 | fclose(f); | |
2196 | } | |
2197 | } | |
2198 | /* Do common processing for the child, such as execing the command. */ | |
2199 | do_child(command, pw, term, display, auth_proto, auth_data, ttyname); | |
2200 | /* NOTREACHED */ | |
8efc0c15 | 2201 | } |
5260325f | 2202 | if (pid < 0) |
2203 | packet_disconnect("fork failed: %.100s", strerror(errno)); | |
2204 | /* Parent. Close the slave side of the pseudo tty. */ | |
2205 | close(ttyfd); | |
2206 | ||
aa3378df | 2207 | /* |
2208 | * Create another descriptor of the pty master side for use as the | |
2209 | * standard input. We could use the original descriptor, but this | |
2210 | * simplifies code in server_loop. The descriptor is bidirectional. | |
2211 | */ | |
5260325f | 2212 | fdout = dup(ptyfd); |
2213 | if (fdout < 0) | |
2214 | packet_disconnect("dup failed: %.100s", strerror(errno)); | |
2215 | ||
aa3378df | 2216 | /* |
2217 | * Add a cleanup function to clear the utmp entry and record logout | |
2218 | * time in case we call fatal() (e.g., the connection gets closed). | |
2219 | */ | |
5260325f | 2220 | cleanup_context.pid = pid; |
2221 | cleanup_context.ttyname = ttyname; | |
2222 | fatal_add_cleanup(pty_cleanup_proc, (void *) &cleanup_context); | |
2223 | ||
2224 | /* Enter interactive session. */ | |
2225 | server_loop(pid, ptyfd, fdout, -1); | |
2226 | /* server_loop has not closed ptyfd and fdout. */ | |
2227 | ||
2228 | /* Cancel the cleanup function. */ | |
2229 | fatal_remove_cleanup(pty_cleanup_proc, (void *) &cleanup_context); | |
2230 | ||
2231 | /* Record that the user has logged out. */ | |
2232 | record_logout(pid, ttyname); | |
2233 | ||
2234 | /* Release the pseudo-tty. */ | |
2235 | pty_release(ttyname); | |
2236 | ||
aa3378df | 2237 | /* |
2238 | * Close the server side of the socket pairs. We must do this after | |
2239 | * the pty cleanup, so that another process doesn't get this pty | |
2240 | * while we're still cleaning up. | |
2241 | */ | |
5260325f | 2242 | close(ptyfd); |
2243 | close(fdout); | |
8efc0c15 | 2244 | } |
2245 | ||
5260325f | 2246 | /* |
2247 | * Sets the value of the given variable in the environment. If the variable | |
2248 | * already exists, its value is overriden. | |
2249 | */ | |
2250 | void | |
2251 | child_set_env(char ***envp, unsigned int *envsizep, const char *name, | |
2252 | const char *value) | |
8efc0c15 | 2253 | { |
5260325f | 2254 | unsigned int i, namelen; |
2255 | char **env; | |
2256 | ||
aa3378df | 2257 | /* |
2258 | * Find the slot where the value should be stored. If the variable | |
2259 | * already exists, we reuse the slot; otherwise we append a new slot | |
2260 | * at the end of the array, expanding if necessary. | |
2261 | */ | |
5260325f | 2262 | env = *envp; |
2263 | namelen = strlen(name); | |
2264 | for (i = 0; env[i]; i++) | |
2265 | if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=') | |
2266 | break; | |
2267 | if (env[i]) { | |
aa3378df | 2268 | /* Reuse the slot. */ |
5260325f | 2269 | xfree(env[i]); |
2270 | } else { | |
aa3378df | 2271 | /* New variable. Expand if necessary. */ |
5260325f | 2272 | if (i >= (*envsizep) - 1) { |
2273 | (*envsizep) += 50; | |
2274 | env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *)); | |
2275 | } | |
2276 | /* Need to set the NULL pointer at end of array beyond the new slot. */ | |
2277 | env[i + 1] = NULL; | |
8efc0c15 | 2278 | } |
2279 | ||
5260325f | 2280 | /* Allocate space and format the variable in the appropriate slot. */ |
2281 | env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1); | |
2282 | snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value); | |
8efc0c15 | 2283 | } |
2284 | ||
5260325f | 2285 | /* |
2286 | * Reads environment variables from the given file and adds/overrides them | |
2287 | * into the environment. If the file does not exist, this does nothing. | |
2288 | * Otherwise, it must consist of empty lines, comments (line starts with '#') | |
2289 | * and assignments of the form name=value. No other forms are allowed. | |
2290 | */ | |
2291 | void | |
2292 | read_environment_file(char ***env, unsigned int *envsize, | |
2293 | const char *filename) | |
8efc0c15 | 2294 | { |
5260325f | 2295 | FILE *f; |
2296 | char buf[4096]; | |
2297 | char *cp, *value; | |
2298 | ||
5260325f | 2299 | f = fopen(filename, "r"); |
2300 | if (!f) | |
2301 | return; | |
2302 | ||
5260325f | 2303 | while (fgets(buf, sizeof(buf), f)) { |
aa3378df | 2304 | for (cp = buf; *cp == ' ' || *cp == '\t'; cp++) |
2305 | ; | |
5260325f | 2306 | if (!*cp || *cp == '#' || *cp == '\n') |
2307 | continue; | |
5260325f | 2308 | if (strchr(cp, '\n')) |
2309 | *strchr(cp, '\n') = '\0'; | |
5260325f | 2310 | value = strchr(cp, '='); |
2311 | if (value == NULL) { | |
2312 | fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf); | |
2313 | continue; | |
2314 | } | |
aa3378df | 2315 | /* Replace the equals sign by nul, and advance value to the value string. */ |
5260325f | 2316 | *value = '\0'; |
2317 | value++; | |
5260325f | 2318 | child_set_env(env, envsize, cp, value); |
2319 | } | |
5260325f | 2320 | fclose(f); |
8efc0c15 | 2321 | } |
2322 | ||
5260325f | 2323 | /* |
2324 | * Performs common processing for the child, such as setting up the | |
2325 | * environment, closing extra file descriptors, setting the user and group | |
2326 | * ids, and executing the command or shell. | |
2327 | */ | |
2328 | void | |
2329 | do_child(const char *command, struct passwd * pw, const char *term, | |
2330 | const char *display, const char *auth_proto, | |
2331 | const char *auth_data, const char *ttyname) | |
8efc0c15 | 2332 | { |
5260325f | 2333 | const char *shell, *cp = NULL; |
2334 | char buf[256]; | |
2335 | FILE *f; | |
2336 | unsigned int envsize, i; | |
2337 | char **env; | |
2338 | extern char **environ; | |
2339 | struct stat st; | |
2340 | char *argv[10]; | |
8efc0c15 | 2341 | |
e1a9c08d | 2342 | #ifndef HAVE_LIBPAM /* pam_nologin handles this */ |
5260325f | 2343 | /* Check /etc/nologin. */ |
2344 | f = fopen("/etc/nologin", "r"); | |
2345 | if (f) { | |
2346 | /* /etc/nologin exists. Print its contents and exit. */ | |
2347 | while (fgets(buf, sizeof(buf), f)) | |
2348 | fputs(buf, stderr); | |
2349 | fclose(f); | |
2350 | if (pw->pw_uid != 0) | |
2351 | exit(254); | |
2352 | } | |
e35c1dc2 | 2353 | #endif /* HAVE_LIBPAM */ |
2354 | ||
2355 | #ifdef HAVE_SETLOGIN | |
5260325f | 2356 | /* Set login name in the kernel. */ |
2357 | if (setlogin(pw->pw_name) < 0) | |
2358 | error("setlogin failed: %s", strerror(errno)); | |
e35c1dc2 | 2359 | #endif /* HAVE_SETLOGIN */ |
8efc0c15 | 2360 | |
5260325f | 2361 | /* Set uid, gid, and groups. */ |
2362 | /* Login(1) does this as well, and it needs uid 0 for the "-h" | |
2363 | switch, so we let login(1) to this for us. */ | |
2364 | if (!options.use_login) { | |
2365 | if (getuid() == 0 || geteuid() == 0) { | |
2366 | if (setgid(pw->pw_gid) < 0) { | |
2367 | perror("setgid"); | |
2368 | exit(1); | |
2369 | } | |
2370 | /* Initialize the group list. */ | |
2371 | if (initgroups(pw->pw_name, pw->pw_gid) < 0) { | |
2372 | perror("initgroups"); | |
2373 | exit(1); | |
2374 | } | |
2375 | endgrent(); | |
2376 | ||
2377 | /* Permanently switch to the desired uid. */ | |
2378 | permanently_set_uid(pw->pw_uid); | |
2379 | } | |
2380 | if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid) | |
2381 | fatal("Failed to set uids to %d.", (int) pw->pw_uid); | |
2382 | } | |
aa3378df | 2383 | /* |
2384 | * Get the shell from the password data. An empty shell field is | |
2385 | * legal, and means /bin/sh. | |
2386 | */ | |
5260325f | 2387 | shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell; |
8efc0c15 | 2388 | |
2389 | #ifdef AFS | |
5260325f | 2390 | /* Try to get AFS tokens for the local cell. */ |
2391 | if (k_hasafs()) { | |
2392 | char cell[64]; | |
2393 | ||
2394 | if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0) | |
2395 | krb_afslog(cell, 0); | |
2396 | ||
2397 | krb_afslog(0, 0); | |
2398 | } | |
8efc0c15 | 2399 | #endif /* AFS */ |
5260325f | 2400 | |
aa3378df | 2401 | /* Initialize the environment. */ |
5260325f | 2402 | envsize = 100; |
2403 | env = xmalloc(envsize * sizeof(char *)); | |
2404 | env[0] = NULL; | |
2405 | ||
2406 | if (!options.use_login) { | |
2407 | /* Set basic environment. */ | |
2408 | child_set_env(&env, &envsize, "USER", pw->pw_name); | |
2409 | child_set_env(&env, &envsize, "LOGNAME", pw->pw_name); | |
2410 | child_set_env(&env, &envsize, "HOME", pw->pw_dir); | |
2411 | child_set_env(&env, &envsize, "PATH", _PATH_STDPATH); | |
2412 | ||
2413 | snprintf(buf, sizeof buf, "%.200s/%.50s", | |
2414 | _PATH_MAILDIR, pw->pw_name); | |
2415 | child_set_env(&env, &envsize, "MAIL", buf); | |
2416 | ||
2417 | /* Normal systems set SHELL by default. */ | |
2418 | child_set_env(&env, &envsize, "SHELL", shell); | |
2419 | } | |
5260325f | 2420 | if (getenv("TZ")) |
2421 | child_set_env(&env, &envsize, "TZ", getenv("TZ")); | |
2422 | ||
2423 | /* Set custom environment options from RSA authentication. */ | |
2424 | while (custom_environment) { | |
2425 | struct envstring *ce = custom_environment; | |
2426 | char *s = ce->s; | |
2427 | int i; | |
2428 | for (i = 0; s[i] != '=' && s[i]; i++); | |
2429 | if (s[i] == '=') { | |
2430 | s[i] = 0; | |
2431 | child_set_env(&env, &envsize, s, s + i + 1); | |
2432 | } | |
2433 | custom_environment = ce->next; | |
2434 | xfree(ce->s); | |
2435 | xfree(ce); | |
8efc0c15 | 2436 | } |
8efc0c15 | 2437 | |
5260325f | 2438 | snprintf(buf, sizeof buf, "%.50s %d %d", |
2439 | get_remote_ipaddr(), get_remote_port(), options.port); | |
2440 | child_set_env(&env, &envsize, "SSH_CLIENT", buf); | |
8efc0c15 | 2441 | |
5260325f | 2442 | if (ttyname) |
2443 | child_set_env(&env, &envsize, "SSH_TTY", ttyname); | |
5260325f | 2444 | if (term) |
2445 | child_set_env(&env, &envsize, "TERM", term); | |
5260325f | 2446 | if (display) |
2447 | child_set_env(&env, &envsize, "DISPLAY", display); | |
8efc0c15 | 2448 | |
2449 | #ifdef KRB4 | |
5260325f | 2450 | { |
2451 | extern char *ticket; | |
2452 | ||
2453 | if (ticket) | |
2454 | child_set_env(&env, &envsize, "KRBTKFILE", ticket); | |
2455 | } | |
8efc0c15 | 2456 | #endif /* KRB4 */ |
2457 | ||
bb0dd7f6 | 2458 | #ifdef HAVE_LIBPAM |
5260325f | 2459 | /* Pull in any environment variables that may have been set by PAM. */ |
2460 | { | |
2461 | char *equals, var_name[512], var_val[512]; | |
2462 | char **pam_env = pam_getenvlist((pam_handle_t *)pamh); | |
2463 | int i; | |
2464 | for(i = 0; pam_env && pam_env[i]; i++) { | |
2465 | equals = strstr(pam_env[i], "="); | |
2466 | if ((strlen(pam_env[i]) < (sizeof(var_name) - 1)) && (equals != NULL)) | |
2467 | { | |
9c7b6dfd | 2468 | debug("PAM environment: %s=%s", var_name, var_val); |
5260325f | 2469 | memset(var_name, '\0', sizeof(var_name)); |
2470 | memset(var_val, '\0', sizeof(var_val)); | |
2471 | strncpy(var_name, pam_env[i], equals - pam_env[i]); | |
2472 | strcpy(var_val, equals + 1); | |
2473 | child_set_env(&env, &envsize, var_name, var_val); | |
2474 | } | |
2475 | } | |
2476 | } | |
bb0dd7f6 | 2477 | #endif /* HAVE_LIBPAM */ |
2478 | ||
5260325f | 2479 | if (xauthfile) |
2480 | child_set_env(&env, &envsize, "XAUTHORITY", xauthfile); | |
2481 | ||
5260325f | 2482 | if (auth_get_socket_name() != NULL) |
2483 | child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME, | |
2484 | auth_get_socket_name()); | |
2485 | ||
aa3378df | 2486 | /* read $HOME/.ssh/environment. */ |
5260325f | 2487 | if (!options.use_login) { |
2488 | snprintf(buf, sizeof buf, "%.200s/.ssh/environment", pw->pw_dir); | |
2489 | read_environment_file(&env, &envsize, buf); | |
2490 | } | |
5260325f | 2491 | if (debug_flag) { |
aa3378df | 2492 | /* dump the environment */ |
5260325f | 2493 | fprintf(stderr, "Environment:\n"); |
2494 | for (i = 0; env[i]; i++) | |
2495 | fprintf(stderr, " %.200s\n", env[i]); | |
2496 | } | |
aa3378df | 2497 | /* |
2498 | * Close the connection descriptors; note that this is the child, and | |
2499 | * the server will still have the socket open, and it is important | |
2500 | * that we do not shutdown it. Note that the descriptors cannot be | |
2501 | * closed before building the environment, as we call | |
2502 | * get_remote_ipaddr there. | |
2503 | */ | |
5260325f | 2504 | if (packet_get_connection_in() == packet_get_connection_out()) |
2505 | close(packet_get_connection_in()); | |
2506 | else { | |
2507 | close(packet_get_connection_in()); | |
2508 | close(packet_get_connection_out()); | |
2509 | } | |
aa3378df | 2510 | /* |
2511 | * Close all descriptors related to channels. They will still remain | |
2512 | * open in the parent. | |
2513 | */ | |
2514 | /* XXX better use close-on-exec? -markus */ | |
5260325f | 2515 | channel_close_all(); |
2516 | ||
aa3378df | 2517 | /* |
2518 | * Close any extra file descriptors. Note that there may still be | |
2519 | * descriptors left by system functions. They will be closed later. | |
2520 | */ | |
5260325f | 2521 | endpwent(); |
2522 | endhostent(); | |
2523 | ||
aa3378df | 2524 | /* |
2525 | * Close any extra open file descriptors so that we don\'t have them | |
2526 | * hanging around in clients. Note that we want to do this after | |
2527 | * initgroups, because at least on Solaris 2.3 it leaves file | |
2528 | * descriptors open. | |
2529 | */ | |
5260325f | 2530 | for (i = 3; i < 64; i++) |
2531 | close(i); | |
2532 | ||
2533 | /* Change current directory to the user\'s home directory. */ | |
2534 | if (chdir(pw->pw_dir) < 0) | |
2535 | fprintf(stderr, "Could not chdir to home directory %s: %s\n", | |
2536 | pw->pw_dir, strerror(errno)); | |
2537 | ||
aa3378df | 2538 | /* |
2539 | * Must take new environment into use so that .ssh/rc, /etc/sshrc and | |
2540 | * xauth are run in the proper environment. | |
2541 | */ | |
5260325f | 2542 | environ = env; |
2543 | ||
aa3378df | 2544 | /* |
2545 | * Run $HOME/.ssh/rc, /etc/sshrc, or xauth (whichever is found first | |
2546 | * in this order). | |
2547 | */ | |
5260325f | 2548 | if (!options.use_login) { |
2549 | if (stat(SSH_USER_RC, &st) >= 0) { | |
2550 | if (debug_flag) | |
2551 | fprintf(stderr, "Running /bin/sh %s\n", SSH_USER_RC); | |
2552 | ||
2553 | f = popen("/bin/sh " SSH_USER_RC, "w"); | |
2554 | if (f) { | |
2555 | if (auth_proto != NULL && auth_data != NULL) | |
2556 | fprintf(f, "%s %s\n", auth_proto, auth_data); | |
2557 | pclose(f); | |
2558 | } else | |
2559 | fprintf(stderr, "Could not run %s\n", SSH_USER_RC); | |
2560 | } else if (stat(SSH_SYSTEM_RC, &st) >= 0) { | |
2561 | if (debug_flag) | |
2562 | fprintf(stderr, "Running /bin/sh %s\n", SSH_SYSTEM_RC); | |
2563 | ||
2564 | f = popen("/bin/sh " SSH_SYSTEM_RC, "w"); | |
2565 | if (f) { | |
2566 | if (auth_proto != NULL && auth_data != NULL) | |
2567 | fprintf(f, "%s %s\n", auth_proto, auth_data); | |
2568 | pclose(f); | |
2569 | } else | |
2570 | fprintf(stderr, "Could not run %s\n", SSH_SYSTEM_RC); | |
2571 | } | |
8efc0c15 | 2572 | #ifdef XAUTH_PATH |
5260325f | 2573 | else { |
aa3378df | 2574 | /* Add authority data to .Xauthority if appropriate. */ |
5260325f | 2575 | if (auth_proto != NULL && auth_data != NULL) { |
2576 | if (debug_flag) | |
2577 | fprintf(stderr, "Running %.100s add %.100s %.100s %.100s\n", | |
2578 | XAUTH_PATH, display, auth_proto, auth_data); | |
2579 | ||
2580 | f = popen(XAUTH_PATH " -q -", "w"); | |
2581 | if (f) { | |
2582 | fprintf(f, "add %s %s %s\n", display, auth_proto, auth_data); | |
2583 | fclose(f); | |
2584 | } else | |
2585 | fprintf(stderr, "Could not run %s -q -\n", XAUTH_PATH); | |
2586 | } | |
2587 | } | |
8efc0c15 | 2588 | #endif /* XAUTH_PATH */ |
2589 | ||
5260325f | 2590 | /* Get the last component of the shell name. */ |
2591 | cp = strrchr(shell, '/'); | |
2592 | if (cp) | |
2593 | cp++; | |
2594 | else | |
2595 | cp = shell; | |
2596 | } | |
aa3378df | 2597 | /* |
2598 | * If we have no command, execute the shell. In this case, the shell | |
2599 | * name to be passed in argv[0] is preceded by '-' to indicate that | |
2600 | * this is a login shell. | |
2601 | */ | |
5260325f | 2602 | if (!command) { |
2603 | if (!options.use_login) { | |
2604 | char buf[256]; | |
2605 | ||
aa3378df | 2606 | /* |
2607 | * Check for mail if we have a tty and it was enabled | |
2608 | * in server options. | |
2609 | */ | |
5260325f | 2610 | if (ttyname && options.check_mail) { |
2611 | char *mailbox; | |
2612 | struct stat mailstat; | |
2613 | mailbox = getenv("MAIL"); | |
2614 | if (mailbox != NULL) { | |
2615 | if (stat(mailbox, &mailstat) != 0 || mailstat.st_size == 0) | |
2616 | printf("No mail.\n"); | |
2617 | else if (mailstat.st_mtime < mailstat.st_atime) | |
2618 | printf("You have mail.\n"); | |
2619 | else | |
2620 | printf("You have new mail.\n"); | |
2621 | } | |
2622 | } | |
2623 | /* Start the shell. Set initial character to '-'. */ | |
2624 | buf[0] = '-'; | |
2625 | strncpy(buf + 1, cp, sizeof(buf) - 1); | |
2626 | buf[sizeof(buf) - 1] = 0; | |
2627 | ||
2628 | /* Execute the shell. */ | |
2629 | argv[0] = buf; | |
2630 | argv[1] = NULL; | |
2631 | execve(shell, argv, env); | |
2632 | ||
2633 | /* Executing the shell failed. */ | |
2634 | perror(shell); | |
2635 | exit(1); | |
2636 | ||
2637 | } else { | |
2638 | /* Launch login(1). */ | |
2639 | ||
2640 | execl(LOGIN_PROGRAM, "login", "-h", get_remote_ipaddr(), | |
2641 | "-p", "-f", "--", pw->pw_name, NULL); | |
2642 | ||
2643 | /* Login couldn't be executed, die. */ | |
2644 | ||
2645 | perror("login"); | |
2646 | exit(1); | |
2647 | } | |
2648 | } | |
aa3378df | 2649 | /* |
2650 | * Execute the command using the user's shell. This uses the -c | |
2651 | * option to execute the command. | |
2652 | */ | |
5260325f | 2653 | argv[0] = (char *) cp; |
2654 | argv[1] = "-c"; | |
2655 | argv[2] = (char *) command; | |
2656 | argv[3] = NULL; | |
2657 | execve(shell, argv, env); | |
2658 | perror(shell); | |
2659 | exit(1); | |
8efc0c15 | 2660 | } |