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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 | ||
7303768f | 16 | #ifdef HAVE_POLL_H |
17 | # include <poll.h> | |
18 | #else /* HAVE_POLL_H */ | |
19 | # ifdef HAVE_SYS_POLL_H | |
20 | # include <sys/poll.h> | |
21 | # endif /* HAVE_SYS_POLL_H */ | |
22 | #endif /* HAVE_POLL_H */ | |
2d86a6cc | 23 | |
8efc0c15 | 24 | #include "xmalloc.h" |
25 | #include "rsa.h" | |
26 | #include "ssh.h" | |
27 | #include "pty.h" | |
28 | #include "packet.h" | |
29 | #include "buffer.h" | |
30 | #include "cipher.h" | |
31 | #include "mpaux.h" | |
32 | #include "servconf.h" | |
33 | #include "uidswap.h" | |
34 | #include "compat.h" | |
35 | ||
36 | #ifdef LIBWRAP | |
37 | #include <tcpd.h> | |
38 | #include <syslog.h> | |
39 | int allow_severity = LOG_INFO; | |
40 | int deny_severity = LOG_WARNING; | |
41 | #endif /* LIBWRAP */ | |
42 | ||
43 | #ifndef O_NOCTTY | |
44 | #define O_NOCTTY 0 | |
45 | #endif | |
46 | ||
8efc0c15 | 47 | /* Local Xauthority file. */ |
6a17f9c2 | 48 | static char *xauthfile = NULL; |
8efc0c15 | 49 | |
50 | /* Server configuration options. */ | |
51 | ServerOptions options; | |
52 | ||
53 | /* Name of the server configuration file. */ | |
54 | char *config_file_name = SERVER_CONFIG_FILE; | |
55 | ||
5260325f | 56 | /* |
57 | * Debug mode flag. This can be set on the command line. If debug | |
58 | * mode is enabled, extra debugging output will be sent to the system | |
59 | * log, the daemon will not go to background, and will exit after processing | |
60 | * the first connection. | |
61 | */ | |
8efc0c15 | 62 | int debug_flag = 0; |
63 | ||
64 | /* Flag indicating that the daemon is being started from inetd. */ | |
65 | int inetd_flag = 0; | |
66 | ||
6a17f9c2 | 67 | /* debug goes to stderr unless inetd_flag is set */ |
68 | int log_stderr = 0; | |
69 | ||
8efc0c15 | 70 | /* argv[0] without path. */ |
71 | char *av0; | |
72 | ||
73 | /* Saved arguments to main(). */ | |
74 | char **saved_argv; | |
75 | ||
aa3378df | 76 | /* |
77 | * This is set to the socket that the server is listening; this is used in | |
78 | * the SIGHUP signal handler. | |
79 | */ | |
8efc0c15 | 80 | int listen_sock; |
81 | ||
aa3378df | 82 | /* |
83 | * the client's version string, passed by sshd2 in compat mode. if != NULL, | |
84 | * sshd will skip the version-number exchange | |
85 | */ | |
5260325f | 86 | char *client_version_string = NULL; |
87 | ||
88 | /* Flags set in auth-rsa from authorized_keys flags. These are set in auth-rsa.c. */ | |
8efc0c15 | 89 | int no_port_forwarding_flag = 0; |
90 | int no_agent_forwarding_flag = 0; | |
91 | int no_x11_forwarding_flag = 0; | |
92 | int no_pty_flag = 0; | |
5260325f | 93 | |
94 | /* RSA authentication "command=" option. */ | |
95 | char *forced_command = NULL; | |
96 | ||
97 | /* RSA authentication "environment=" options. */ | |
98 | struct envstring *custom_environment = NULL; | |
8efc0c15 | 99 | |
100 | /* Session id for the current session. */ | |
101 | unsigned char session_id[16]; | |
102 | ||
aa3378df | 103 | /* |
104 | * Any really sensitive data in the application is contained in this | |
105 | * structure. The idea is that this structure could be locked into memory so | |
106 | * that the pages do not get written into swap. However, there are some | |
107 | * problems. The private key contains BIGNUMs, and we do not (in principle) | |
108 | * have access to the internals of them, and locking just the structure is | |
109 | * not very useful. Currently, memory locking is not implemented. | |
110 | */ | |
5260325f | 111 | struct { |
112 | RSA *private_key; /* Private part of server key. */ | |
113 | RSA *host_key; /* Private part of host key. */ | |
8efc0c15 | 114 | } sensitive_data; |
115 | ||
aa3378df | 116 | /* |
117 | * Flag indicating whether the current session key has been used. This flag | |
118 | * is set whenever the key is used, and cleared when the key is regenerated. | |
119 | */ | |
8efc0c15 | 120 | int key_used = 0; |
121 | ||
122 | /* This is set to true when SIGHUP is received. */ | |
123 | int received_sighup = 0; | |
124 | ||
125 | /* Public side of the server key. This value is regenerated regularly with | |
126 | the private key. */ | |
127 | RSA *public_key; | |
128 | ||
129 | /* Prototypes for various functions defined later in this file. */ | |
e7c0f9d5 | 130 | void do_connection(); |
131 | void do_authentication(char *user); | |
5260325f | 132 | void do_authloop(struct passwd * pw); |
e7c0f9d5 | 133 | void do_fake_authloop(char *user); |
5260325f | 134 | void do_authenticated(struct passwd * pw); |
135 | void do_exec_pty(const char *command, int ptyfd, int ttyfd, | |
136 | const char *ttyname, struct passwd * pw, const char *term, | |
137 | const char *display, const char *auth_proto, | |
138 | const char *auth_data); | |
139 | void do_exec_no_pty(const char *command, struct passwd * pw, | |
140 | const char *display, const char *auth_proto, | |
141 | const char *auth_data); | |
142 | void do_child(const char *command, struct passwd * pw, const char *term, | |
8efc0c15 | 143 | const char *display, const char *auth_proto, |
144 | const char *auth_data, const char *ttyname); | |
e7c0f9d5 | 145 | |
5aecb327 | 146 | #ifdef HAVE_LIBPAM |
8efc0c15 | 147 | static int pamconv(int num_msg, const struct pam_message **msg, |
5260325f | 148 | struct pam_response **resp, void *appdata_ptr); |
20c43d8c | 149 | int do_pam_auth(const char *user, const char *password); |
8946db53 | 150 | void do_pam_account(char *username, char *remote_user); |
151 | void do_pam_session(char *username, char *ttyname); | |
d813bc69 | 152 | void pam_cleanup_proc(void *context); |
8efc0c15 | 153 | |
154 | static struct pam_conv conv = { | |
5260325f | 155 | pamconv, |
156 | NULL | |
8efc0c15 | 157 | }; |
d813bc69 | 158 | struct pam_handle_t *pamh = NULL; |
159 | const char *pampasswd = NULL; | |
e1a9c08d | 160 | char *pamconv_msg = NULL; |
8efc0c15 | 161 | |
162 | static int pamconv(int num_msg, const struct pam_message **msg, | |
8de3263e | 163 | struct pam_response **resp, void *appdata_ptr) |
8efc0c15 | 164 | { |
5260325f | 165 | struct pam_response *reply; |
166 | int count; | |
167 | size_t msg_len; | |
168 | char *p; | |
169 | ||
170 | /* PAM will free this later */ | |
171 | reply = malloc(num_msg * sizeof(*reply)); | |
172 | if (reply == NULL) | |
173 | return PAM_CONV_ERR; | |
174 | ||
175 | for(count = 0; count < num_msg; count++) { | |
176 | switch (msg[count]->msg_style) { | |
177 | case PAM_PROMPT_ECHO_OFF: | |
178 | if (pampasswd == NULL) { | |
179 | free(reply); | |
180 | return PAM_CONV_ERR; | |
181 | } | |
182 | reply[count].resp_retcode = PAM_SUCCESS; | |
183 | reply[count].resp = xstrdup(pampasswd); | |
184 | break; | |
185 | ||
186 | case PAM_TEXT_INFO: | |
187 | reply[count].resp_retcode = PAM_SUCCESS; | |
188 | reply[count].resp = xstrdup(""); | |
189 | ||
190 | if (msg[count]->msg == NULL) | |
191 | break; | |
192 | ||
193 | debug("Adding PAM message: %s", msg[count]->msg); | |
194 | ||
195 | msg_len = strlen(msg[count]->msg); | |
196 | if (pamconv_msg) { | |
197 | size_t n = strlen(pamconv_msg); | |
198 | pamconv_msg = xrealloc(pamconv_msg, n + msg_len + 2); | |
199 | p = pamconv_msg + n; | |
200 | } else { | |
201 | pamconv_msg = p = xmalloc(msg_len + 2); | |
202 | } | |
203 | memcpy(p, msg[count]->msg, msg_len); | |
204 | p[msg_len] = '\n'; | |
205 | p[msg_len + 1] = '\0'; | |
206 | break; | |
207 | ||
208 | case PAM_PROMPT_ECHO_ON: | |
209 | case PAM_ERROR_MSG: | |
210 | default: | |
211 | free(reply); | |
212 | return PAM_CONV_ERR; | |
213 | } | |
e1a9c08d | 214 | } |
5260325f | 215 | |
216 | *resp = reply; | |
217 | ||
218 | return PAM_SUCCESS; | |
8efc0c15 | 219 | } |
220 | ||
221 | void pam_cleanup_proc(void *context) | |
222 | { | |
5260325f | 223 | int pam_retval; |
224 | ||
225 | if (pamh != NULL) | |
226 | { | |
227 | pam_retval = pam_close_session((pam_handle_t *)pamh, 0); | |
228 | if (pam_retval != PAM_SUCCESS) { | |
229 | log("Cannot close PAM session: %.200s", | |
230 | PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); | |
231 | } | |
232 | ||
233 | pam_retval = pam_end((pam_handle_t *)pamh, pam_retval); | |
234 | if (pam_retval != PAM_SUCCESS) { | |
235 | log("Cannot release PAM authentication: %.200s", | |
236 | PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); | |
237 | } | |
238 | } | |
d813bc69 | 239 | } |
240 | ||
20c43d8c | 241 | int do_pam_auth(const char *user, const char *password) |
f498ed15 | 242 | { |
243 | int pam_retval; | |
244 | ||
36a5b38e | 245 | if ((options.permit_empty_passwd == 0) && (password[0] == '\0') |
246 | return 0; | |
247 | ||
f498ed15 | 248 | pampasswd = password; |
249 | ||
20c43d8c | 250 | pam_retval = pam_authenticate((pam_handle_t *)pamh, 0); |
f498ed15 | 251 | if (pam_retval == PAM_SUCCESS) { |
20c43d8c | 252 | debug("PAM Password authentication accepted for user \"%.100s\"", user); |
f498ed15 | 253 | return 1; |
254 | } else { | |
20c43d8c | 255 | debug("PAM Password authentication for \"%.100s\" failed: %s", |
256 | user, PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); | |
f498ed15 | 257 | return 0; |
258 | } | |
259 | } | |
260 | ||
8946db53 | 261 | void do_pam_account(char *username, char *remote_user) |
d813bc69 | 262 | { |
5260325f | 263 | int pam_retval; |
264 | ||
9c7b6dfd | 265 | debug("PAM setting rhost to \"%.200s\"", get_canonical_hostname()); |
266 | pam_retval = pam_set_item((pam_handle_t *)pamh, PAM_RHOST, | |
267 | get_canonical_hostname()); | |
268 | if (pam_retval != PAM_SUCCESS) { | |
269 | log("PAM set rhost failed: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); | |
270 | do_fake_authloop(username); | |
5260325f | 271 | } |
272 | ||
273 | if (remote_user != NULL) { | |
274 | debug("PAM setting ruser to \"%.200s\"", remote_user); | |
275 | pam_retval = pam_set_item((pam_handle_t *)pamh, PAM_RUSER, remote_user); | |
276 | if (pam_retval != PAM_SUCCESS) { | |
277 | log("PAM set ruser failed: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); | |
278 | do_fake_authloop(username); | |
279 | } | |
280 | } | |
281 | ||
282 | pam_retval = pam_acct_mgmt((pam_handle_t *)pamh, 0); | |
283 | if (pam_retval != PAM_SUCCESS) { | |
284 | log("PAM rejected by account configuration: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); | |
285 | do_fake_authloop(username); | |
286 | } | |
8946db53 | 287 | } |
5260325f | 288 | |
8946db53 | 289 | void do_pam_session(char *username, char *ttyname) |
290 | { | |
291 | int pam_retval; | |
292 | ||
293 | if (ttyname != NULL) { | |
294 | debug("PAM setting tty to \"%.200s\"", ttyname); | |
295 | pam_retval = pam_set_item((pam_handle_t *)pamh, PAM_TTY, ttyname); | |
296 | if (pam_retval != PAM_SUCCESS) | |
297 | fatal("PAM set tty failed: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); | |
5260325f | 298 | } |
8946db53 | 299 | |
300 | pam_retval = pam_open_session((pam_handle_t *)pamh, 0); | |
301 | if (pam_retval != PAM_SUCCESS) | |
302 | fatal("PAM session setup failed: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); | |
8efc0c15 | 303 | } |
5aecb327 | 304 | #endif /* HAVE_LIBPAM */ |
8efc0c15 | 305 | |
5260325f | 306 | /* |
307 | * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; | |
308 | * the effect is to reread the configuration file (and to regenerate | |
309 | * the server key). | |
310 | */ | |
311 | void | |
312 | sighup_handler(int sig) | |
8efc0c15 | 313 | { |
5260325f | 314 | received_sighup = 1; |
315 | signal(SIGHUP, sighup_handler); | |
8efc0c15 | 316 | } |
317 | ||
5260325f | 318 | /* |
319 | * Called from the main program after receiving SIGHUP. | |
320 | * Restarts the server. | |
321 | */ | |
322 | void | |
323 | sighup_restart() | |
8efc0c15 | 324 | { |
5260325f | 325 | log("Received SIGHUP; restarting."); |
326 | close(listen_sock); | |
327 | execv(saved_argv[0], saved_argv); | |
328 | log("RESTART FAILED: av0='%s', error: %s.", av0, strerror(errno)); | |
329 | exit(1); | |
8efc0c15 | 330 | } |
331 | ||
5260325f | 332 | /* |
333 | * Generic signal handler for terminating signals in the master daemon. | |
334 | * These close the listen socket; not closing it seems to cause "Address | |
335 | * already in use" problems on some machines, which is inconvenient. | |
336 | */ | |
337 | void | |
338 | sigterm_handler(int sig) | |
8efc0c15 | 339 | { |
5260325f | 340 | log("Received signal %d; terminating.", sig); |
341 | close(listen_sock); | |
342 | exit(255); | |
8efc0c15 | 343 | } |
344 | ||
5260325f | 345 | /* |
346 | * SIGCHLD handler. This is called whenever a child dies. This will then | |
347 | * reap any zombies left by exited c. | |
348 | */ | |
349 | void | |
350 | main_sigchld_handler(int sig) | |
8efc0c15 | 351 | { |
5260325f | 352 | int save_errno = errno; |
353 | int status; | |
5ad13cd7 | 354 | |
5260325f | 355 | while (waitpid(-1, &status, WNOHANG) > 0) |
356 | ; | |
5ad13cd7 | 357 | |
5260325f | 358 | signal(SIGCHLD, main_sigchld_handler); |
359 | errno = save_errno; | |
8efc0c15 | 360 | } |
361 | ||
5260325f | 362 | /* |
363 | * Signal handler for the alarm after the login grace period has expired. | |
364 | */ | |
365 | void | |
366 | grace_alarm_handler(int sig) | |
8efc0c15 | 367 | { |
5260325f | 368 | /* Close the connection. */ |
369 | packet_close(); | |
8efc0c15 | 370 | |
5260325f | 371 | /* Log error and exit. */ |
372 | fatal("Timeout before authentication for %s.", get_remote_ipaddr()); | |
373 | } | |
8efc0c15 | 374 | |
5260325f | 375 | /* |
376 | * convert ssh auth msg type into description | |
377 | */ | |
378 | char * | |
379 | get_authname(int type) | |
8efc0c15 | 380 | { |
5260325f | 381 | switch (type) { |
382 | case SSH_CMSG_AUTH_PASSWORD: | |
383 | return "password"; | |
384 | case SSH_CMSG_AUTH_RSA: | |
385 | return "rsa"; | |
386 | case SSH_CMSG_AUTH_RHOSTS_RSA: | |
387 | return "rhosts-rsa"; | |
388 | case SSH_CMSG_AUTH_RHOSTS: | |
389 | return "rhosts"; | |
390 | #ifdef KRB4 | |
391 | case SSH_CMSG_AUTH_KERBEROS: | |
392 | return "kerberos"; | |
393 | #endif | |
394 | #ifdef SKEY | |
395 | case SSH_CMSG_AUTH_TIS_RESPONSE: | |
396 | return "s/key"; | |
397 | #endif | |
398 | } | |
399 | fatal("get_authname: unknown auth %d: internal error", type); | |
400 | return NULL; | |
8efc0c15 | 401 | } |
402 | ||
5260325f | 403 | /* |
404 | * Signal handler for the key regeneration alarm. Note that this | |
405 | * alarm only occurs in the daemon waiting for connections, and it does not | |
406 | * do anything with the private key or random state before forking. | |
407 | * Thus there should be no concurrency control/asynchronous execution | |
408 | * problems. | |
409 | */ | |
410 | void | |
411 | key_regeneration_alarm(int sig) | |
412 | { | |
413 | int save_errno = errno; | |
414 | ||
415 | /* Check if we should generate a new key. */ | |
416 | if (key_used) { | |
417 | /* This should really be done in the background. */ | |
418 | log("Generating new %d bit RSA key.", options.server_key_bits); | |
419 | ||
420 | if (sensitive_data.private_key != NULL) | |
421 | RSA_free(sensitive_data.private_key); | |
422 | sensitive_data.private_key = RSA_new(); | |
423 | ||
424 | if (public_key != NULL) | |
425 | RSA_free(public_key); | |
426 | public_key = RSA_new(); | |
427 | ||
428 | rsa_generate_key(sensitive_data.private_key, public_key, | |
429 | options.server_key_bits); | |
430 | arc4random_stir(); | |
431 | key_used = 0; | |
432 | log("RSA key generation complete."); | |
433 | } | |
434 | /* Reschedule the alarm. */ | |
435 | signal(SIGALRM, key_regeneration_alarm); | |
436 | alarm(options.key_regeneration_time); | |
437 | errno = save_errno; | |
438 | } | |
8efc0c15 | 439 | |
5260325f | 440 | /* |
441 | * Main program for the daemon. | |
442 | */ | |
8efc0c15 | 443 | int |
444 | main(int ac, char **av) | |
445 | { | |
5260325f | 446 | extern char *optarg; |
447 | extern int optind; | |
448 | int opt, aux, sock_in, sock_out, newsock, i, pid, on = 1; | |
449 | int remote_major, remote_minor; | |
450 | int silentrsa = 0; | |
2d86a6cc | 451 | struct pollfd fds; |
5260325f | 452 | struct sockaddr_in sin; |
453 | char buf[100]; /* Must not be larger than remote_version. */ | |
454 | char remote_version[100]; /* Must be at least as big as buf. */ | |
455 | const char *remote_ip; | |
456 | int remote_port; | |
457 | char *comment; | |
458 | FILE *f; | |
459 | struct linger linger; | |
460 | ||
461 | /* Save argv[0]. */ | |
462 | saved_argv = av; | |
463 | if (strchr(av[0], '/')) | |
464 | av0 = strrchr(av[0], '/') + 1; | |
465 | else | |
466 | av0 = av[0]; | |
467 | ||
468 | /* Initialize configuration options to their default values. */ | |
469 | initialize_server_options(&options); | |
470 | ||
471 | /* Parse command-line arguments. */ | |
472 | while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:diqQ")) != EOF) { | |
473 | switch (opt) { | |
474 | case 'f': | |
475 | config_file_name = optarg; | |
476 | break; | |
477 | case 'd': | |
478 | debug_flag = 1; | |
479 | options.log_level = SYSLOG_LEVEL_DEBUG; | |
480 | break; | |
481 | case 'i': | |
482 | inetd_flag = 1; | |
483 | break; | |
484 | case 'Q': | |
485 | silentrsa = 1; | |
486 | break; | |
487 | case 'q': | |
488 | options.log_level = SYSLOG_LEVEL_QUIET; | |
489 | break; | |
490 | case 'b': | |
491 | options.server_key_bits = atoi(optarg); | |
492 | break; | |
493 | case 'p': | |
494 | options.port = atoi(optarg); | |
495 | break; | |
496 | case 'g': | |
497 | options.login_grace_time = atoi(optarg); | |
498 | break; | |
499 | case 'k': | |
500 | options.key_regeneration_time = atoi(optarg); | |
501 | break; | |
502 | case 'h': | |
503 | options.host_key_file = optarg; | |
504 | break; | |
505 | case 'V': | |
506 | client_version_string = optarg; | |
507 | /* only makes sense with inetd_flag, i.e. no listen() */ | |
508 | inetd_flag = 1; | |
509 | break; | |
510 | case '?': | |
511 | default: | |
512 | fprintf(stderr, "sshd version %s\n", SSH_VERSION); | |
513 | fprintf(stderr, "Usage: %s [options]\n", av0); | |
514 | fprintf(stderr, "Options:\n"); | |
aa3378df | 515 | fprintf(stderr, " -f file Configuration file (default %s)\n", SERVER_CONFIG_FILE); |
5260325f | 516 | fprintf(stderr, " -d Debugging mode\n"); |
517 | fprintf(stderr, " -i Started from inetd\n"); | |
518 | fprintf(stderr, " -q Quiet (no logging)\n"); | |
519 | fprintf(stderr, " -p port Listen on the specified port (default: 22)\n"); | |
520 | fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n"); | |
521 | fprintf(stderr, " -g seconds Grace period for authentication (default: 300)\n"); | |
522 | fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n"); | |
523 | fprintf(stderr, " -h file File from which to read host key (default: %s)\n", | |
524 | HOST_KEY_FILE); | |
525 | exit(1); | |
526 | } | |
527 | } | |
528 | ||
529 | /* check if RSA support exists */ | |
530 | if (rsa_alive() == 0) { | |
531 | if (silentrsa == 0) | |
532 | printf("sshd: no RSA support in libssl and libcrypto -- exiting. See ssl(8)\n"); | |
533 | log("no RSA support in libssl and libcrypto -- exiting. See ssl(8)"); | |
534 | exit(1); | |
535 | } | |
536 | /* Read server configuration options from the configuration file. */ | |
537 | read_server_config(&options, config_file_name); | |
538 | ||
539 | /* Fill in default values for those options not explicitly set. */ | |
540 | fill_default_server_options(&options); | |
541 | ||
542 | /* Check certain values for sanity. */ | |
543 | if (options.server_key_bits < 512 || | |
544 | options.server_key_bits > 32768) { | |
545 | fprintf(stderr, "Bad server key size.\n"); | |
546 | exit(1); | |
547 | } | |
548 | if (options.port < 1 || options.port > 65535) { | |
549 | fprintf(stderr, "Bad port number.\n"); | |
550 | exit(1); | |
551 | } | |
552 | /* Check that there are no remaining arguments. */ | |
553 | if (optind < ac) { | |
554 | fprintf(stderr, "Extra argument %s.\n", av[optind]); | |
555 | exit(1); | |
8efc0c15 | 556 | } |
5260325f | 557 | /* Force logging to stderr while loading the private host key |
558 | unless started from inetd */ | |
559 | log_init(av0, options.log_level, options.log_facility, !inetd_flag); | |
560 | ||
561 | debug("sshd version %.100s", SSH_VERSION); | |
562 | ||
563 | sensitive_data.host_key = RSA_new(); | |
564 | errno = 0; | |
565 | /* Load the host key. It must have empty passphrase. */ | |
566 | if (!load_private_key(options.host_key_file, "", | |
567 | sensitive_data.host_key, &comment)) { | |
568 | error("Could not load host key: %.200s: %.100s", | |
569 | options.host_key_file, strerror(errno)); | |
570 | exit(1); | |
571 | } | |
572 | xfree(comment); | |
573 | ||
574 | /* Initialize the log (it is reinitialized below in case we | |
575 | forked). */ | |
576 | if (debug_flag && !inetd_flag) | |
577 | log_stderr = 1; | |
578 | log_init(av0, options.log_level, options.log_facility, log_stderr); | |
579 | ||
580 | /* If not in debugging mode, and not started from inetd, | |
581 | disconnect from the controlling terminal, and fork. The | |
582 | original process exits. */ | |
583 | if (!debug_flag && !inetd_flag) { | |
8efc0c15 | 584 | #ifdef TIOCNOTTY |
5260325f | 585 | int fd; |
8efc0c15 | 586 | #endif /* TIOCNOTTY */ |
5260325f | 587 | if (daemon(0, 0) < 0) |
588 | fatal("daemon() failed: %.200s", strerror(errno)); | |
589 | ||
590 | /* Disconnect from the controlling tty. */ | |
8efc0c15 | 591 | #ifdef TIOCNOTTY |
5260325f | 592 | fd = open("/dev/tty", O_RDWR | O_NOCTTY); |
593 | if (fd >= 0) { | |
594 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
595 | close(fd); | |
596 | } | |
8efc0c15 | 597 | #endif /* TIOCNOTTY */ |
8efc0c15 | 598 | } |
5260325f | 599 | /* Reinitialize the log (because of the fork above). */ |
600 | log_init(av0, options.log_level, options.log_facility, log_stderr); | |
601 | ||
602 | /* Check that server and host key lengths differ sufficiently. | |
603 | This is necessary to make double encryption work with rsaref. | |
604 | Oh, I hate software patents. I dont know if this can go? Niels */ | |
605 | if (options.server_key_bits > | |
606 | BN_num_bits(sensitive_data.host_key->n) - SSH_KEY_BITS_RESERVED && | |
607 | options.server_key_bits < | |
608 | BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) { | |
609 | options.server_key_bits = | |
610 | BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED; | |
611 | debug("Forcing server key to %d bits to make it differ from host key.", | |
612 | options.server_key_bits); | |
8efc0c15 | 613 | } |
5260325f | 614 | /* Do not display messages to stdout in RSA code. */ |
615 | rsa_set_verbose(0); | |
616 | ||
617 | /* Initialize the random number generator. */ | |
618 | arc4random_stir(); | |
619 | ||
620 | /* Chdir to the root directory so that the current disk can be | |
621 | unmounted if desired. */ | |
622 | chdir("/"); | |
623 | ||
624 | /* Close connection cleanly after attack. */ | |
625 | cipher_attack_detected = packet_disconnect; | |
626 | ||
627 | /* Start listening for a socket, unless started from inetd. */ | |
628 | if (inetd_flag) { | |
629 | int s1, s2; | |
630 | s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */ | |
631 | s2 = dup(s1); | |
632 | sock_in = dup(0); | |
633 | sock_out = dup(1); | |
634 | /* We intentionally do not close the descriptors 0, 1, and 2 | |
635 | as our code for setting the descriptors won\'t work | |
636 | if ttyfd happens to be one of those. */ | |
637 | debug("inetd sockets after dupping: %d, %d", sock_in, sock_out); | |
638 | ||
639 | public_key = RSA_new(); | |
640 | sensitive_data.private_key = RSA_new(); | |
641 | ||
642 | log("Generating %d bit RSA key.", options.server_key_bits); | |
643 | rsa_generate_key(sensitive_data.private_key, public_key, | |
644 | options.server_key_bits); | |
645 | arc4random_stir(); | |
646 | log("RSA key generation complete."); | |
647 | } else { | |
648 | /* Create socket for listening. */ | |
649 | listen_sock = socket(AF_INET, SOCK_STREAM, 0); | |
650 | if (listen_sock < 0) | |
651 | fatal("socket: %.100s", strerror(errno)); | |
652 | ||
653 | /* Set socket options. We try to make the port reusable | |
654 | and have it close as fast as possible without waiting | |
655 | in unnecessary wait states on close. */ | |
656 | setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, (void *) &on, | |
657 | sizeof(on)); | |
658 | linger.l_onoff = 1; | |
659 | linger.l_linger = 5; | |
660 | setsockopt(listen_sock, SOL_SOCKET, SO_LINGER, (void *) &linger, | |
661 | sizeof(linger)); | |
662 | ||
5260325f | 663 | memset(&sin, 0, sizeof(sin)); |
664 | sin.sin_family = AF_INET; | |
665 | sin.sin_addr = options.listen_addr; | |
666 | sin.sin_port = htons(options.port); | |
667 | ||
5260325f | 668 | if (bind(listen_sock, (struct sockaddr *) & sin, sizeof(sin)) < 0) { |
669 | error("bind: %.100s", strerror(errno)); | |
670 | shutdown(listen_sock, SHUT_RDWR); | |
671 | close(listen_sock); | |
672 | fatal("Bind to port %d failed.", options.port); | |
673 | } | |
674 | if (!debug_flag) { | |
aa3378df | 675 | /* |
676 | * Record our pid in /etc/sshd_pid to make it easier | |
677 | * to kill the correct sshd. We don\'t want to do | |
678 | * this before the bind above because the bind will | |
679 | * fail if there already is a daemon, and this will | |
680 | * overwrite any old pid in the file. | |
681 | */ | |
5260325f | 682 | f = fopen(SSH_DAEMON_PID_FILE, "w"); |
683 | if (f) { | |
684 | fprintf(f, "%u\n", (unsigned int) getpid()); | |
685 | fclose(f); | |
686 | } | |
8efc0c15 | 687 | } |
8efc0c15 | 688 | |
5260325f | 689 | log("Server listening on port %d.", options.port); |
690 | if (listen(listen_sock, 5) < 0) | |
691 | fatal("listen: %.100s", strerror(errno)); | |
692 | ||
693 | public_key = RSA_new(); | |
694 | sensitive_data.private_key = RSA_new(); | |
695 | ||
696 | log("Generating %d bit RSA key.", options.server_key_bits); | |
697 | rsa_generate_key(sensitive_data.private_key, public_key, | |
698 | options.server_key_bits); | |
699 | arc4random_stir(); | |
700 | log("RSA key generation complete."); | |
701 | ||
702 | /* Schedule server key regeneration alarm. */ | |
703 | signal(SIGALRM, key_regeneration_alarm); | |
704 | alarm(options.key_regeneration_time); | |
705 | ||
706 | /* Arrange to restart on SIGHUP. The handler needs listen_sock. */ | |
707 | signal(SIGHUP, sighup_handler); | |
708 | signal(SIGTERM, sigterm_handler); | |
709 | signal(SIGQUIT, sigterm_handler); | |
710 | ||
711 | /* Arrange SIGCHLD to be caught. */ | |
712 | signal(SIGCHLD, main_sigchld_handler); | |
713 | ||
aa3378df | 714 | /* |
715 | * Stay listening for connections until the system crashes or | |
716 | * the daemon is killed with a signal. | |
717 | */ | |
5260325f | 718 | for (;;) { |
719 | if (received_sighup) | |
720 | sighup_restart(); | |
2d86a6cc | 721 | /* Wait in poll until there is a connection. */ |
722 | memset(&fds, 0, sizeof(fds)); | |
723 | fds.fd = listen_sock; | |
724 | fds.events = POLLIN; | |
725 | if (poll(&fds, 1, -1) == -1) { | |
726 | if (errno == EINTR) | |
727 | continue; | |
728 | fatal("poll: %.100s", strerror(errno)); | |
729 | /*NOTREACHED*/ | |
730 | } | |
731 | if (fds.revents == 0) | |
732 | continue; | |
5260325f | 733 | aux = sizeof(sin); |
734 | newsock = accept(listen_sock, (struct sockaddr *) & sin, &aux); | |
735 | if (received_sighup) | |
736 | sighup_restart(); | |
737 | if (newsock < 0) { | |
738 | if (errno == EINTR) | |
739 | continue; | |
740 | error("accept: %.100s", strerror(errno)); | |
741 | continue; | |
742 | } | |
aa3378df | 743 | /* |
744 | * Got connection. Fork a child to handle it, unless | |
745 | * we are in debugging mode. | |
746 | */ | |
5260325f | 747 | if (debug_flag) { |
aa3378df | 748 | /* |
749 | * In debugging mode. Close the listening | |
750 | * socket, and start processing the | |
751 | * connection without forking. | |
752 | */ | |
5260325f | 753 | debug("Server will not fork when running in debugging mode."); |
754 | close(listen_sock); | |
755 | sock_in = newsock; | |
756 | sock_out = newsock; | |
757 | pid = getpid(); | |
758 | break; | |
759 | } else { | |
aa3378df | 760 | /* |
761 | * Normal production daemon. Fork, and have | |
762 | * the child process the connection. The | |
763 | * parent continues listening. | |
764 | */ | |
5260325f | 765 | if ((pid = fork()) == 0) { |
aa3378df | 766 | /* |
767 | * Child. Close the listening socket, and start using the | |
768 | * accepted socket. Reinitialize logging (since our pid has | |
769 | * changed). We break out of the loop to handle the connection. | |
770 | */ | |
5260325f | 771 | close(listen_sock); |
772 | sock_in = newsock; | |
773 | sock_out = newsock; | |
774 | log_init(av0, options.log_level, options.log_facility, log_stderr); | |
775 | break; | |
776 | } | |
777 | } | |
778 | ||
779 | /* Parent. Stay in the loop. */ | |
780 | if (pid < 0) | |
781 | error("fork: %.100s", strerror(errno)); | |
782 | else | |
783 | debug("Forked child %d.", pid); | |
784 | ||
785 | /* Mark that the key has been used (it was "given" to the child). */ | |
786 | key_used = 1; | |
787 | ||
788 | arc4random_stir(); | |
789 | ||
790 | /* Close the new socket (the child is now taking care of it). */ | |
791 | close(newsock); | |
792 | } | |
793 | } | |
8efc0c15 | 794 | |
5260325f | 795 | /* This is the child processing a new connection. */ |
796 | ||
aa3378df | 797 | /* |
798 | * Disable the key regeneration alarm. We will not regenerate the | |
799 | * key since we are no longer in a position to give it to anyone. We | |
800 | * will not restart on SIGHUP since it no longer makes sense. | |
801 | */ | |
5260325f | 802 | alarm(0); |
803 | signal(SIGALRM, SIG_DFL); | |
804 | signal(SIGHUP, SIG_DFL); | |
805 | signal(SIGTERM, SIG_DFL); | |
806 | signal(SIGQUIT, SIG_DFL); | |
807 | signal(SIGCHLD, SIG_DFL); | |
808 | ||
aa3378df | 809 | /* |
810 | * Set socket options for the connection. We want the socket to | |
811 | * close as fast as possible without waiting for anything. If the | |
812 | * connection is not a socket, these will do nothing. | |
813 | */ | |
814 | /* setsockopt(sock_in, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */ | |
5260325f | 815 | linger.l_onoff = 1; |
816 | linger.l_linger = 5; | |
817 | setsockopt(sock_in, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger)); | |
818 | ||
aa3378df | 819 | /* |
820 | * Register our connection. This turns encryption off because we do | |
821 | * not have a key. | |
822 | */ | |
5260325f | 823 | packet_set_connection(sock_in, sock_out); |
824 | ||
825 | remote_port = get_remote_port(); | |
826 | remote_ip = get_remote_ipaddr(); | |
827 | ||
828 | /* Check whether logins are denied from this host. */ | |
829 | #ifdef LIBWRAP | |
830 | { | |
831 | struct request_info req; | |
8efc0c15 | 832 | |
5260325f | 833 | request_init(&req, RQ_DAEMON, av0, RQ_FILE, sock_in, NULL); |
834 | fromhost(&req); | |
8efc0c15 | 835 | |
5260325f | 836 | if (!hosts_access(&req)) { |
837 | close(sock_in); | |
838 | close(sock_out); | |
839 | refuse(&req); | |
840 | } | |
841 | verbose("Connection from %.500s port %d", eval_client(&req), remote_port); | |
8efc0c15 | 842 | } |
8efc0c15 | 843 | #else |
5260325f | 844 | /* Log the connection. */ |
845 | verbose("Connection from %.500s port %d", remote_ip, remote_port); | |
8efc0c15 | 846 | #endif /* LIBWRAP */ |
847 | ||
aa3378df | 848 | /* |
849 | * We don\'t want to listen forever unless the other side | |
850 | * successfully authenticates itself. So we set up an alarm which is | |
851 | * cleared after successful authentication. A limit of zero | |
852 | * indicates no limit. Note that we don\'t set the alarm in debugging | |
853 | * mode; it is just annoying to have the server exit just when you | |
854 | * are about to discover the bug. | |
855 | */ | |
5260325f | 856 | signal(SIGALRM, grace_alarm_handler); |
857 | if (!debug_flag) | |
858 | alarm(options.login_grace_time); | |
859 | ||
860 | if (client_version_string != NULL) { | |
861 | /* we are exec'ed by sshd2, so skip exchange of protocol version */ | |
862 | strlcpy(buf, client_version_string, sizeof(buf)); | |
863 | } else { | |
864 | /* Send our protocol version identification. */ | |
865 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", | |
866 | PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION); | |
a408af76 | 867 | if (atomicio(write, sock_out, buf, strlen(buf)) != strlen(buf)) |
5260325f | 868 | fatal("Could not write ident string to %s.", get_remote_ipaddr()); |
869 | ||
870 | /* Read other side\'s version identification. */ | |
871 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
872 | if (read(sock_in, &buf[i], 1) != 1) | |
873 | fatal("Did not receive ident string from %s.", get_remote_ipaddr()); | |
874 | if (buf[i] == '\r') { | |
875 | buf[i] = '\n'; | |
876 | buf[i + 1] = 0; | |
877 | break; | |
878 | } | |
879 | if (buf[i] == '\n') { | |
880 | /* buf[i] == '\n' */ | |
881 | buf[i + 1] = 0; | |
882 | break; | |
883 | } | |
884 | } | |
885 | buf[sizeof(buf) - 1] = 0; | |
8efc0c15 | 886 | } |
5260325f | 887 | |
aa3378df | 888 | /* |
889 | * Check that the versions match. In future this might accept | |
890 | * several versions and set appropriate flags to handle them. | |
891 | */ | |
5260325f | 892 | if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor, |
a408af76 | 893 | remote_version) != 3) { |
894 | char *s = "Protocol mismatch.\n"; | |
895 | ||
896 | (void) atomicio(write, sock_out, s, strlen(s)); | |
5260325f | 897 | close(sock_in); |
898 | close(sock_out); | |
899 | fatal("Bad protocol version identification '%.100s' from %s", | |
900 | buf, get_remote_ipaddr()); | |
901 | } | |
902 | debug("Client protocol version %d.%d; client software version %.100s", | |
903 | remote_major, remote_minor, remote_version); | |
904 | if (remote_major != PROTOCOL_MAJOR) { | |
a408af76 | 905 | char *s = "Protocol major versions differ.\n"; |
906 | ||
907 | (void) atomicio(write, sock_out, s, strlen(s)); | |
5260325f | 908 | close(sock_in); |
909 | close(sock_out); | |
910 | fatal("Protocol major versions differ for %s: %d vs. %d", | |
911 | get_remote_ipaddr(), | |
912 | PROTOCOL_MAJOR, remote_major); | |
8efc0c15 | 913 | } |
5260325f | 914 | /* Check that the client has sufficiently high software version. */ |
915 | if (remote_major == 1 && remote_minor < 3) | |
916 | packet_disconnect("Your ssh version is too old and is no longer supported. Please install a newer version."); | |
917 | ||
918 | if (remote_major == 1 && remote_minor == 3) { | |
919 | enable_compat13(); | |
920 | if (strcmp(remote_version, "OpenSSH-1.1") != 0) { | |
921 | debug("Agent forwarding disabled, remote version is not compatible."); | |
922 | no_agent_forwarding_flag = 1; | |
923 | } | |
924 | } | |
aa3378df | 925 | /* |
926 | * Check that the connection comes from a privileged port. Rhosts- | |
927 | * and Rhosts-RSA-Authentication only make sense from priviledged | |
928 | * programs. Of course, if the intruder has root access on his local | |
929 | * machine, he can connect from any port. So do not use these | |
930 | * authentication methods from machines that you do not trust. | |
931 | */ | |
5260325f | 932 | if (remote_port >= IPPORT_RESERVED || |
933 | remote_port < IPPORT_RESERVED / 2) { | |
934 | options.rhosts_authentication = 0; | |
935 | options.rhosts_rsa_authentication = 0; | |
936 | } | |
937 | packet_set_nonblocking(); | |
938 | ||
939 | /* Handle the connection. */ | |
940 | do_connection(); | |
8efc0c15 | 941 | |
942 | #ifdef KRB4 | |
5260325f | 943 | /* Cleanup user's ticket cache file. */ |
944 | if (options.kerberos_ticket_cleanup) | |
945 | (void) dest_tkt(); | |
8efc0c15 | 946 | #endif /* KRB4 */ |
947 | ||
5260325f | 948 | /* Cleanup user's local Xauthority file. */ |
949 | if (xauthfile) | |
950 | unlink(xauthfile); | |
8efc0c15 | 951 | |
5260325f | 952 | /* The connection has been terminated. */ |
953 | verbose("Closing connection to %.100s", remote_ip); | |
8efc0c15 | 954 | |
5aecb327 | 955 | #ifdef HAVE_LIBPAM |
5260325f | 956 | { |
957 | int retval; | |
8efc0c15 | 958 | |
5260325f | 959 | if (pamh != NULL) { |
960 | debug("Closing PAM session."); | |
961 | retval = pam_close_session((pam_handle_t *)pamh, 0); | |
8efc0c15 | 962 | |
5260325f | 963 | debug("Terminating PAM library."); |
964 | if (pam_end((pam_handle_t *)pamh, retval) != PAM_SUCCESS) | |
965 | log("Cannot release PAM authentication."); | |
966 | ||
967 | fatal_remove_cleanup(&pam_cleanup_proc, NULL); | |
968 | } | |
969 | } | |
970 | #endif /* HAVE_LIBPAM */ | |
8efc0c15 | 971 | |
5260325f | 972 | packet_close(); |
973 | exit(0); | |
974 | } | |
8efc0c15 | 975 | |
5260325f | 976 | /* |
977 | * Process an incoming connection. Protocol version identifiers have already | |
978 | * been exchanged. This sends server key and performs the key exchange. | |
979 | * Server and host keys will no longer be needed after this functions. | |
980 | */ | |
e7c0f9d5 | 981 | void |
982 | do_connection() | |
8efc0c15 | 983 | { |
5260325f | 984 | int i, len; |
985 | BIGNUM *session_key_int; | |
986 | unsigned char session_key[SSH_SESSION_KEY_LENGTH]; | |
987 | unsigned char check_bytes[8]; | |
988 | char *user; | |
989 | unsigned int cipher_type, auth_mask, protocol_flags; | |
95f1eccc | 990 | int plen, slen, ulen; |
5260325f | 991 | u_int32_t rand = 0; |
992 | ||
aa3378df | 993 | /* |
994 | * Generate check bytes that the client must send back in the user | |
995 | * packet in order for it to be accepted; this is used to defy ip | |
996 | * spoofing attacks. Note that this only works against somebody | |
997 | * doing IP spoofing from a remote machine; any machine on the local | |
998 | * network can still see outgoing packets and catch the random | |
999 | * cookie. This only affects rhosts authentication, and this is one | |
1000 | * of the reasons why it is inherently insecure. | |
1001 | */ | |
5260325f | 1002 | for (i = 0; i < 8; i++) { |
1003 | if (i % 4 == 0) | |
1004 | rand = arc4random(); | |
1005 | check_bytes[i] = rand & 0xff; | |
1006 | rand >>= 8; | |
1007 | } | |
1008 | ||
aa3378df | 1009 | /* |
1010 | * Send our public key. We include in the packet 64 bits of random | |
1011 | * data that must be matched in the reply in order to prevent IP | |
1012 | * spoofing. | |
1013 | */ | |
5260325f | 1014 | packet_start(SSH_SMSG_PUBLIC_KEY); |
1015 | for (i = 0; i < 8; i++) | |
1016 | packet_put_char(check_bytes[i]); | |
1017 | ||
1018 | /* Store our public server RSA key. */ | |
1019 | packet_put_int(BN_num_bits(public_key->n)); | |
1020 | packet_put_bignum(public_key->e); | |
1021 | packet_put_bignum(public_key->n); | |
1022 | ||
1023 | /* Store our public host RSA key. */ | |
1024 | packet_put_int(BN_num_bits(sensitive_data.host_key->n)); | |
1025 | packet_put_bignum(sensitive_data.host_key->e); | |
1026 | packet_put_bignum(sensitive_data.host_key->n); | |
1027 | ||
1028 | /* Put protocol flags. */ | |
1029 | packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); | |
1030 | ||
1031 | /* Declare which ciphers we support. */ | |
1032 | packet_put_int(cipher_mask()); | |
1033 | ||
1034 | /* Declare supported authentication types. */ | |
1035 | auth_mask = 0; | |
1036 | if (options.rhosts_authentication) | |
1037 | auth_mask |= 1 << SSH_AUTH_RHOSTS; | |
1038 | if (options.rhosts_rsa_authentication) | |
1039 | auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; | |
1040 | if (options.rsa_authentication) | |
1041 | auth_mask |= 1 << SSH_AUTH_RSA; | |
8efc0c15 | 1042 | #ifdef KRB4 |
5260325f | 1043 | if (options.kerberos_authentication) |
1044 | auth_mask |= 1 << SSH_AUTH_KERBEROS; | |
8efc0c15 | 1045 | #endif |
1046 | #ifdef AFS | |
5260325f | 1047 | if (options.kerberos_tgt_passing) |
1048 | auth_mask |= 1 << SSH_PASS_KERBEROS_TGT; | |
1049 | if (options.afs_token_passing) | |
1050 | auth_mask |= 1 << SSH_PASS_AFS_TOKEN; | |
8efc0c15 | 1051 | #endif |
5260325f | 1052 | #ifdef SKEY |
1053 | if (options.skey_authentication == 1) | |
1054 | auth_mask |= 1 << SSH_AUTH_TIS; | |
1055 | #endif | |
1056 | if (options.password_authentication) | |
1057 | auth_mask |= 1 << SSH_AUTH_PASSWORD; | |
1058 | packet_put_int(auth_mask); | |
1059 | ||
1060 | /* Send the packet and wait for it to be sent. */ | |
1061 | packet_send(); | |
1062 | packet_write_wait(); | |
1063 | ||
1064 | debug("Sent %d bit public key and %d bit host key.", | |
1065 | BN_num_bits(public_key->n), BN_num_bits(sensitive_data.host_key->n)); | |
1066 | ||
1067 | /* Read clients reply (cipher type and session key). */ | |
1068 | packet_read_expect(&plen, SSH_CMSG_SESSION_KEY); | |
1069 | ||
2d86a6cc | 1070 | /* Get cipher type and check whether we accept this. */ |
5260325f | 1071 | cipher_type = packet_get_char(); |
1072 | ||
2d86a6cc | 1073 | if (!(cipher_mask() & (1 << cipher_type))) |
1074 | packet_disconnect("Warning: client selects unsupported cipher."); | |
1075 | ||
5260325f | 1076 | /* Get check bytes from the packet. These must match those we |
1077 | sent earlier with the public key packet. */ | |
1078 | for (i = 0; i < 8; i++) | |
1079 | if (check_bytes[i] != packet_get_char()) | |
1080 | packet_disconnect("IP Spoofing check bytes do not match."); | |
1081 | ||
1082 | debug("Encryption type: %.200s", cipher_name(cipher_type)); | |
1083 | ||
1084 | /* Get the encrypted integer. */ | |
1085 | session_key_int = BN_new(); | |
1086 | packet_get_bignum(session_key_int, &slen); | |
1087 | ||
5260325f | 1088 | protocol_flags = packet_get_int(); |
1089 | packet_set_protocol_flags(protocol_flags); | |
1090 | ||
1091 | packet_integrity_check(plen, 1 + 8 + slen + 4, SSH_CMSG_SESSION_KEY); | |
1092 | ||
aa3378df | 1093 | /* |
1094 | * Decrypt it using our private server key and private host key (key | |
1095 | * with larger modulus first). | |
1096 | */ | |
5260325f | 1097 | if (BN_cmp(sensitive_data.private_key->n, sensitive_data.host_key->n) > 0) { |
1098 | /* Private key has bigger modulus. */ | |
1099 | if (BN_num_bits(sensitive_data.private_key->n) < | |
1100 | BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) { | |
1101 | fatal("do_connection: %s: private_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", | |
1102 | get_remote_ipaddr(), | |
1103 | BN_num_bits(sensitive_data.private_key->n), | |
1104 | BN_num_bits(sensitive_data.host_key->n), | |
1105 | SSH_KEY_BITS_RESERVED); | |
1106 | } | |
1107 | rsa_private_decrypt(session_key_int, session_key_int, | |
1108 | sensitive_data.private_key); | |
1109 | rsa_private_decrypt(session_key_int, session_key_int, | |
1110 | sensitive_data.host_key); | |
1111 | } else { | |
1112 | /* Host key has bigger modulus (or they are equal). */ | |
1113 | if (BN_num_bits(sensitive_data.host_key->n) < | |
1114 | BN_num_bits(sensitive_data.private_key->n) + SSH_KEY_BITS_RESERVED) { | |
1115 | fatal("do_connection: %s: host_key %d < private_key %d + SSH_KEY_BITS_RESERVED %d", | |
1116 | get_remote_ipaddr(), | |
1117 | BN_num_bits(sensitive_data.host_key->n), | |
1118 | BN_num_bits(sensitive_data.private_key->n), | |
1119 | SSH_KEY_BITS_RESERVED); | |
1120 | } | |
1121 | rsa_private_decrypt(session_key_int, session_key_int, | |
1122 | sensitive_data.host_key); | |
1123 | rsa_private_decrypt(session_key_int, session_key_int, | |
1124 | sensitive_data.private_key); | |
1125 | } | |
1126 | ||
5260325f | 1127 | compute_session_id(session_id, check_bytes, |
1128 | sensitive_data.host_key->n, | |
1129 | sensitive_data.private_key->n); | |
1130 | ||
aa3378df | 1131 | /* |
1132 | * Extract session key from the decrypted integer. The key is in the | |
1133 | * least significant 256 bits of the integer; the first byte of the | |
1134 | * key is in the highest bits. | |
1135 | */ | |
5260325f | 1136 | BN_mask_bits(session_key_int, sizeof(session_key) * 8); |
1137 | len = BN_num_bytes(session_key_int); | |
1138 | if (len < 0 || len > sizeof(session_key)) | |
1139 | fatal("do_connection: bad len from %s: session_key_int %d > sizeof(session_key) %d", | |
1140 | get_remote_ipaddr(), | |
1141 | len, sizeof(session_key)); | |
1142 | memset(session_key, 0, sizeof(session_key)); | |
1143 | BN_bn2bin(session_key_int, session_key + sizeof(session_key) - len); | |
1144 | ||
1145 | /* Xor the first 16 bytes of the session key with the session id. */ | |
1146 | for (i = 0; i < 16; i++) | |
1147 | session_key[i] ^= session_id[i]; | |
1148 | ||
1149 | /* Destroy the decrypted integer. It is no longer needed. */ | |
1150 | BN_clear_free(session_key_int); | |
1151 | ||
1152 | /* Set the session key. From this on all communications will be encrypted. */ | |
1153 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); | |
1154 | ||
1155 | /* Destroy our copy of the session key. It is no longer needed. */ | |
1156 | memset(session_key, 0, sizeof(session_key)); | |
1157 | ||
1158 | debug("Received session key; encryption turned on."); | |
1159 | ||
1160 | /* Send an acknowledgement packet. Note that this packet is sent encrypted. */ | |
1161 | packet_start(SSH_SMSG_SUCCESS); | |
1162 | packet_send(); | |
1163 | packet_write_wait(); | |
1164 | ||
1165 | /* Get the name of the user that we wish to log in as. */ | |
1166 | packet_read_expect(&plen, SSH_CMSG_USER); | |
1167 | ||
1168 | /* Get the user name. */ | |
95f1eccc | 1169 | user = packet_get_string(&ulen); |
1170 | packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER); | |
5260325f | 1171 | |
1172 | /* Destroy the private and public keys. They will no longer be needed. */ | |
1173 | RSA_free(public_key); | |
1174 | RSA_free(sensitive_data.private_key); | |
1175 | RSA_free(sensitive_data.host_key); | |
8efc0c15 | 1176 | |
5260325f | 1177 | setproctitle("%s", user); |
1178 | /* Do the authentication. */ | |
1179 | do_authentication(user); | |
1180 | } | |
8efc0c15 | 1181 | |
5260325f | 1182 | /* |
1183 | * Check if the user is allowed to log in via ssh. If user is listed in | |
1184 | * DenyUsers or user's primary group is listed in DenyGroups, false will | |
1185 | * be returned. If AllowUsers isn't empty and user isn't listed there, or | |
1186 | * if AllowGroups isn't empty and user isn't listed there, false will be | |
1187 | * returned. Otherwise true is returned. | |
1188 | * XXX This function should also check if user has a valid shell | |
1189 | */ | |
8efc0c15 | 1190 | static int |
5260325f | 1191 | allowed_user(struct passwd * pw) |
8efc0c15 | 1192 | { |
5260325f | 1193 | struct group *grp; |
1194 | int i; | |
1195 | ||
1196 | /* Shouldn't be called if pw is NULL, but better safe than sorry... */ | |
1197 | if (!pw) | |
1198 | return 0; | |
1199 | ||
1200 | /* XXX Should check for valid login shell */ | |
1201 | ||
1202 | /* Return false if user is listed in DenyUsers */ | |
1203 | if (options.num_deny_users > 0) { | |
1204 | if (!pw->pw_name) | |
1205 | return 0; | |
1206 | for (i = 0; i < options.num_deny_users; i++) | |
1207 | if (match_pattern(pw->pw_name, options.deny_users[i])) | |
1208 | return 0; | |
1209 | } | |
aa3378df | 1210 | /* Return false if AllowUsers isn't empty and user isn't listed there */ |
5260325f | 1211 | if (options.num_allow_users > 0) { |
1212 | if (!pw->pw_name) | |
1213 | return 0; | |
1214 | for (i = 0; i < options.num_allow_users; i++) | |
1215 | if (match_pattern(pw->pw_name, options.allow_users[i])) | |
1216 | break; | |
1217 | /* i < options.num_allow_users iff we break for loop */ | |
1218 | if (i >= options.num_allow_users) | |
1219 | return 0; | |
1220 | } | |
1221 | /* Get the primary group name if we need it. Return false if it fails */ | |
1222 | if (options.num_deny_groups > 0 || options.num_allow_groups > 0) { | |
1223 | grp = getgrgid(pw->pw_gid); | |
1224 | if (!grp) | |
1225 | return 0; | |
1226 | ||
1227 | /* Return false if user's group is listed in DenyGroups */ | |
1228 | if (options.num_deny_groups > 0) { | |
1229 | if (!grp->gr_name) | |
1230 | return 0; | |
1231 | for (i = 0; i < options.num_deny_groups; i++) | |
1232 | if (match_pattern(grp->gr_name, options.deny_groups[i])) | |
1233 | return 0; | |
1234 | } | |
aa3378df | 1235 | /* |
1236 | * Return false if AllowGroups isn't empty and user's group | |
1237 | * isn't listed there | |
1238 | */ | |
5260325f | 1239 | if (options.num_allow_groups > 0) { |
1240 | if (!grp->gr_name) | |
1241 | return 0; | |
1242 | for (i = 0; i < options.num_allow_groups; i++) | |
1243 | if (match_pattern(grp->gr_name, options.allow_groups[i])) | |
1244 | break; | |
1245 | /* i < options.num_allow_groups iff we break for | |
1246 | loop */ | |
1247 | if (i >= options.num_allow_groups) | |
1248 | return 0; | |
1249 | } | |
1250 | } | |
1251 | /* We found no reason not to let this user try to log on... */ | |
1252 | return 1; | |
8efc0c15 | 1253 | } |
1254 | ||
5260325f | 1255 | /* |
1256 | * Performs authentication of an incoming connection. Session key has already | |
1257 | * been exchanged and encryption is enabled. User is the user name to log | |
1258 | * in as (received from the client). | |
1259 | */ | |
8efc0c15 | 1260 | void |
e7c0f9d5 | 1261 | do_authentication(char *user) |
8efc0c15 | 1262 | { |
5260325f | 1263 | struct passwd *pw, pwcopy; |
e7c0f9d5 | 1264 | |
8efc0c15 | 1265 | #ifdef AFS |
5260325f | 1266 | /* If machine has AFS, set process authentication group. */ |
1267 | if (k_hasafs()) { | |
1268 | k_setpag(); | |
1269 | k_unlog(); | |
1270 | } | |
8efc0c15 | 1271 | #endif /* AFS */ |
5260325f | 1272 | |
1273 | /* Verify that the user is a valid user. */ | |
1274 | pw = getpwnam(user); | |
1275 | if (!pw || !allowed_user(pw)) | |
1276 | do_fake_authloop(user); | |
1277 | ||
1278 | /* Take a copy of the returned structure. */ | |
1279 | memset(&pwcopy, 0, sizeof(pwcopy)); | |
1280 | pwcopy.pw_name = xstrdup(pw->pw_name); | |
1281 | pwcopy.pw_passwd = xstrdup(pw->pw_passwd); | |
1282 | pwcopy.pw_uid = pw->pw_uid; | |
1283 | pwcopy.pw_gid = pw->pw_gid; | |
1284 | pwcopy.pw_dir = xstrdup(pw->pw_dir); | |
1285 | pwcopy.pw_shell = xstrdup(pw->pw_shell); | |
1286 | pw = &pwcopy; | |
8efc0c15 | 1287 | |
5aecb327 | 1288 | #ifdef HAVE_LIBPAM |
5260325f | 1289 | { |
1290 | int pam_retval; | |
1291 | ||
1292 | debug("Starting up PAM with username \"%.200s\"", pw->pw_name); | |
e7c0f9d5 | 1293 | |
5260325f | 1294 | pam_retval = pam_start("sshd", pw->pw_name, &conv, (pam_handle_t**)&pamh); |
1295 | if (pam_retval != PAM_SUCCESS) | |
1296 | fatal("PAM initialisation failed: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); | |
e7c0f9d5 | 1297 | |
5260325f | 1298 | fatal_add_cleanup(&pam_cleanup_proc, NULL); |
1299 | } | |
5aecb327 | 1300 | #endif |
0183ea1c | 1301 | |
aa3378df | 1302 | /* |
1303 | * If we are not running as root, the user must have the same uid as | |
1304 | * the server. | |
1305 | */ | |
5260325f | 1306 | if (getuid() != 0 && pw->pw_uid != getuid()) |
1307 | packet_disconnect("Cannot change user when server not running as root."); | |
8efc0c15 | 1308 | |
5260325f | 1309 | debug("Attempting authentication for %.100s.", user); |
8efc0c15 | 1310 | |
5260325f | 1311 | /* If the user has no password, accept authentication immediately. */ |
1312 | if (options.password_authentication && | |
8efc0c15 | 1313 | #ifdef KRB4 |
5260325f | 1314 | (!options.kerberos_authentication || options.kerberos_or_local_passwd) && |
8efc0c15 | 1315 | #endif /* KRB4 */ |
f498ed15 | 1316 | #ifdef HAVE_LIBPAM |
20c43d8c | 1317 | do_pam_auth(pw->pw_name, "")) { |
f498ed15 | 1318 | #else /* HAVE_LIBPAM */ |
5260325f | 1319 | auth_password(pw, "")) { |
f498ed15 | 1320 | #endif /* HAVE_LIBPAM */ |
5260325f | 1321 | /* Authentication with empty password succeeded. */ |
1322 | log("Login for user %s from %.100s, accepted without authentication.", | |
1323 | pw->pw_name, get_remote_ipaddr()); | |
1324 | } else { | |
1325 | /* Loop until the user has been authenticated or the | |
1326 | connection is closed, do_authloop() returns only if | |
1327 | authentication is successfull */ | |
1328 | do_authloop(pw); | |
1329 | } | |
1330 | ||
1331 | /* Check if the user is logging in as root and root logins are disallowed. */ | |
1332 | if (pw->pw_uid == 0 && !options.permit_root_login) { | |
1333 | if (forced_command) | |
1334 | log("Root login accepted for forced command."); | |
1335 | else | |
1336 | packet_disconnect("ROOT LOGIN REFUSED FROM %.200s", | |
1337 | get_canonical_hostname()); | |
1338 | } | |
1339 | /* The user has been authenticated and accepted. */ | |
1340 | packet_start(SSH_SMSG_SUCCESS); | |
1341 | packet_send(); | |
1342 | packet_write_wait(); | |
1343 | ||
1344 | /* Perform session preparation. */ | |
1345 | do_authenticated(pw); | |
e7c0f9d5 | 1346 | } |
8efc0c15 | 1347 | |
5260325f | 1348 | #define AUTH_FAIL_MAX 6 |
1349 | #define AUTH_FAIL_LOG (AUTH_FAIL_MAX/2) | |
1350 | #define AUTH_FAIL_MSG "Too many authentication failures for %.100s" | |
e7c0f9d5 | 1351 | |
5260325f | 1352 | /* |
1353 | * read packets and try to authenticate local user *pw. | |
1354 | * return if authentication is successfull | |
1355 | */ | |
e7c0f9d5 | 1356 | void |
5260325f | 1357 | do_authloop(struct passwd * pw) |
e7c0f9d5 | 1358 | { |
5260325f | 1359 | int attempt = 0; |
1360 | unsigned int bits; | |
1361 | BIGNUM *client_host_key_e, *client_host_key_n; | |
1362 | BIGNUM *n; | |
1363 | char *client_user = NULL, *password = NULL; | |
1364 | char user[1024]; | |
1365 | int plen, dlen, nlen, ulen, elen; | |
1366 | int type = 0; | |
1367 | void (*authlog) (const char *fmt,...) = verbose; | |
e7c0f9d5 | 1368 | |
5260325f | 1369 | /* Indicate that authentication is needed. */ |
1370 | packet_start(SSH_SMSG_FAILURE); | |
1371 | packet_send(); | |
1372 | packet_write_wait(); | |
e7c0f9d5 | 1373 | |
5260325f | 1374 | for (attempt = 1;; attempt++) { |
1375 | int authenticated = 0; | |
1376 | strlcpy(user, "", sizeof user); | |
e7c0f9d5 | 1377 | |
5260325f | 1378 | /* Get a packet from the client. */ |
1379 | type = packet_read(&plen); | |
1380 | ||
1381 | /* Process the packet. */ | |
1382 | switch (type) { | |
e7c0f9d5 | 1383 | #ifdef AFS |
5260325f | 1384 | case SSH_CMSG_HAVE_KERBEROS_TGT: |
1385 | if (!options.kerberos_tgt_passing) { | |
1386 | /* packet_get_all(); */ | |
1387 | verbose("Kerberos tgt passing disabled."); | |
1388 | break; | |
1389 | } else { | |
1390 | /* Accept Kerberos tgt. */ | |
1391 | char *tgt = packet_get_string(&dlen); | |
1392 | packet_integrity_check(plen, 4 + dlen, type); | |
1393 | if (!auth_kerberos_tgt(pw, tgt)) | |
1394 | verbose("Kerberos tgt REFUSED for %s", pw->pw_name); | |
1395 | xfree(tgt); | |
1396 | } | |
1397 | continue; | |
1398 | ||
1399 | case SSH_CMSG_HAVE_AFS_TOKEN: | |
1400 | if (!options.afs_token_passing || !k_hasafs()) { | |
1401 | /* packet_get_all(); */ | |
1402 | verbose("AFS token passing disabled."); | |
1403 | break; | |
1404 | } else { | |
1405 | /* Accept AFS token. */ | |
1406 | char *token_string = packet_get_string(&dlen); | |
1407 | packet_integrity_check(plen, 4 + dlen, type); | |
1408 | if (!auth_afs_token(pw, token_string)) | |
1409 | verbose("AFS token REFUSED for %s", pw->pw_name); | |
1410 | xfree(token_string); | |
1411 | } | |
1412 | continue; | |
8efc0c15 | 1413 | #endif /* AFS */ |
e7c0f9d5 | 1414 | #ifdef KRB4 |
5260325f | 1415 | case SSH_CMSG_AUTH_KERBEROS: |
1416 | if (!options.kerberos_authentication) { | |
1417 | /* packet_get_all(); */ | |
1418 | verbose("Kerberos authentication disabled."); | |
1419 | break; | |
1420 | } else { | |
1421 | /* Try Kerberos v4 authentication. */ | |
1422 | KTEXT_ST auth; | |
1423 | char *tkt_user = NULL; | |
1424 | char *kdata = packet_get_string((unsigned int *) &auth.length); | |
1425 | packet_integrity_check(plen, 4 + auth.length, type); | |
1426 | ||
1427 | if (auth.length < MAX_KTXT_LEN) | |
1428 | memcpy(auth.dat, kdata, auth.length); | |
1429 | xfree(kdata); | |
1430 | ||
1431 | authenticated = auth_krb4(pw->pw_name, &auth, &tkt_user); | |
1432 | ||
1433 | if (authenticated) { | |
1434 | snprintf(user, sizeof user, " tktuser %s", tkt_user); | |
1435 | xfree(tkt_user); | |
1436 | } | |
1437 | } | |
1438 | break; | |
e7c0f9d5 | 1439 | #endif /* KRB4 */ |
5260325f | 1440 | |
1441 | case SSH_CMSG_AUTH_RHOSTS: | |
1442 | if (!options.rhosts_authentication) { | |
1443 | verbose("Rhosts authentication disabled."); | |
1444 | break; | |
1445 | } | |
aa3378df | 1446 | /* |
1447 | * Get client user name. Note that we just have to | |
1448 | * trust the client; this is one reason why rhosts | |
1449 | * authentication is insecure. (Another is | |
1450 | * IP-spoofing on a local network.) | |
1451 | */ | |
5260325f | 1452 | client_user = packet_get_string(&ulen); |
1453 | packet_integrity_check(plen, 4 + ulen, type); | |
1454 | ||
1455 | /* Try to authenticate using /etc/hosts.equiv and | |
1456 | .rhosts. */ | |
1457 | authenticated = auth_rhosts(pw, client_user); | |
1458 | ||
1459 | snprintf(user, sizeof user, " ruser %s", client_user); | |
5aecb327 | 1460 | #ifndef HAVE_LIBPAM |
5260325f | 1461 | xfree(client_user); |
5aecb327 | 1462 | #endif /* HAVE_LIBPAM */ |
5260325f | 1463 | break; |
1464 | ||
1465 | case SSH_CMSG_AUTH_RHOSTS_RSA: | |
1466 | if (!options.rhosts_rsa_authentication) { | |
1467 | verbose("Rhosts with RSA authentication disabled."); | |
1468 | break; | |
1469 | } | |
aa3378df | 1470 | /* |
1471 | * Get client user name. Note that we just have to | |
1472 | * trust the client; root on the client machine can | |
1473 | * claim to be any user. | |
1474 | */ | |
5260325f | 1475 | client_user = packet_get_string(&ulen); |
1476 | ||
1477 | /* Get the client host key. */ | |
1478 | client_host_key_e = BN_new(); | |
1479 | client_host_key_n = BN_new(); | |
1480 | bits = packet_get_int(); | |
1481 | packet_get_bignum(client_host_key_e, &elen); | |
1482 | packet_get_bignum(client_host_key_n, &nlen); | |
1483 | ||
1484 | if (bits != BN_num_bits(client_host_key_n)) | |
1485 | error("Warning: keysize mismatch for client_host_key: " | |
1486 | "actual %d, announced %d", BN_num_bits(client_host_key_n), bits); | |
1487 | packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type); | |
1488 | ||
1489 | authenticated = auth_rhosts_rsa(pw, client_user, | |
1490 | client_host_key_e, client_host_key_n); | |
1491 | BN_clear_free(client_host_key_e); | |
1492 | BN_clear_free(client_host_key_n); | |
1493 | ||
1494 | snprintf(user, sizeof user, " ruser %s", client_user); | |
5aecb327 | 1495 | #ifndef HAVE_LIBPAM |
5260325f | 1496 | xfree(client_user); |
5aecb327 | 1497 | #endif /* HAVE_LIBPAM */ |
5260325f | 1498 | break; |
1499 | ||
1500 | case SSH_CMSG_AUTH_RSA: | |
1501 | if (!options.rsa_authentication) { | |
1502 | verbose("RSA authentication disabled."); | |
1503 | break; | |
1504 | } | |
1505 | /* RSA authentication requested. */ | |
1506 | n = BN_new(); | |
1507 | packet_get_bignum(n, &nlen); | |
1508 | packet_integrity_check(plen, nlen, type); | |
1509 | authenticated = auth_rsa(pw, n); | |
1510 | BN_clear_free(n); | |
1511 | break; | |
1512 | ||
1513 | case SSH_CMSG_AUTH_PASSWORD: | |
1514 | if (!options.password_authentication) { | |
1515 | verbose("Password authentication disabled."); | |
1516 | break; | |
1517 | } | |
aa3378df | 1518 | /* |
1519 | * Read user password. It is in plain text, but was | |
1520 | * transmitted over the encrypted channel so it is | |
1521 | * not visible to an outside observer. | |
1522 | */ | |
5260325f | 1523 | password = packet_get_string(&dlen); |
1524 | packet_integrity_check(plen, 4 + dlen, type); | |
1525 | ||
5aecb327 | 1526 | #ifdef HAVE_LIBPAM |
5260325f | 1527 | /* Do PAM auth with password */ |
20c43d8c | 1528 | authenticated = do_pam_auth(pw->pw_name, password); |
5aecb327 | 1529 | #else /* HAVE_LIBPAM */ |
5260325f | 1530 | /* Try authentication with the password. */ |
1531 | authenticated = auth_password(pw, password); | |
f498ed15 | 1532 | #endif /* HAVE_LIBPAM */ |
5260325f | 1533 | memset(password, 0, strlen(password)); |
1534 | xfree(password); | |
1535 | break; | |
5260325f | 1536 | |
1537 | #ifdef SKEY | |
1538 | case SSH_CMSG_AUTH_TIS: | |
1539 | debug("rcvd SSH_CMSG_AUTH_TIS"); | |
1540 | if (options.skey_authentication == 1) { | |
1541 | char *skeyinfo = skey_keyinfo(pw->pw_name); | |
1542 | if (skeyinfo == NULL) { | |
1543 | debug("generating fake skeyinfo for %.100s.", pw->pw_name); | |
1544 | skeyinfo = skey_fake_keyinfo(pw->pw_name); | |
1545 | } | |
1546 | if (skeyinfo != NULL) { | |
aa3378df | 1547 | /* we send our s/key- in tis-challenge messages */ |
5260325f | 1548 | debug("sending challenge '%s'", skeyinfo); |
1549 | packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE); | |
1550 | packet_put_string(skeyinfo, strlen(skeyinfo)); | |
1551 | packet_send(); | |
1552 | packet_write_wait(); | |
1553 | continue; | |
1554 | } | |
1555 | } | |
1556 | break; | |
1557 | case SSH_CMSG_AUTH_TIS_RESPONSE: | |
1558 | debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE"); | |
1559 | if (options.skey_authentication == 1) { | |
1560 | char *response = packet_get_string(&dlen); | |
1561 | debug("skey response == '%s'", response); | |
1562 | packet_integrity_check(plen, 4 + dlen, type); | |
1563 | authenticated = (skey_haskey(pw->pw_name) == 0 && | |
1564 | skey_passcheck(pw->pw_name, response) != -1); | |
1565 | xfree(response); | |
1566 | } | |
1567 | break; | |
1568 | #else | |
1569 | case SSH_CMSG_AUTH_TIS: | |
1570 | /* TIS Authentication is unsupported */ | |
1571 | log("TIS authentication unsupported."); | |
1572 | break; | |
1573 | #endif | |
1574 | ||
1575 | default: | |
aa3378df | 1576 | /* |
1577 | * Any unknown messages will be ignored (and failure | |
1578 | * returned) during authentication. | |
1579 | */ | |
5260325f | 1580 | log("Unknown message during authentication: type %d", type); |
1581 | break; | |
1582 | } | |
1583 | ||
1584 | /* Raise logging level */ | |
1585 | if (authenticated || | |
1586 | attempt == AUTH_FAIL_LOG || | |
1587 | type == SSH_CMSG_AUTH_PASSWORD) | |
1588 | authlog = log; | |
1589 | ||
1590 | authlog("%s %s for %.200s from %.200s port %d%s", | |
1591 | authenticated ? "Accepted" : "Failed", | |
1592 | get_authname(type), | |
1593 | pw->pw_uid == 0 ? "ROOT" : pw->pw_name, | |
1594 | get_remote_ipaddr(), | |
1595 | get_remote_port(), | |
1596 | user); | |
8efc0c15 | 1597 | |
d465f2ca | 1598 | #ifndef HAVE_LIBPAM |
1599 | if (authenticated) | |
1600 | return; | |
d813bc69 | 1601 | |
d465f2ca | 1602 | if (attempt > AUTH_FAIL_MAX) |
1603 | packet_disconnect(AUTH_FAIL_MSG, pw->pw_name); | |
1604 | #else /* HAVE_LIBPAM */ | |
1605 | if (authenticated) { | |
8946db53 | 1606 | do_pam_account(pw->pw_name, client_user); |
d813bc69 | 1607 | |
d465f2ca | 1608 | if (client_user != NULL) |
1609 | xfree(client_user); | |
5260325f | 1610 | |
5260325f | 1611 | return; |
d465f2ca | 1612 | } |
5260325f | 1613 | |
d465f2ca | 1614 | if (attempt > AUTH_FAIL_MAX) { |
d465f2ca | 1615 | if (client_user != NULL) |
1616 | xfree(client_user); | |
1617 | ||
5260325f | 1618 | packet_disconnect(AUTH_FAIL_MSG, pw->pw_name); |
d465f2ca | 1619 | } |
1620 | #endif /* HAVE_LIBPAM */ | |
5260325f | 1621 | |
1622 | /* Send a message indicating that the authentication attempt failed. */ | |
1623 | packet_start(SSH_SMSG_FAILURE); | |
1624 | packet_send(); | |
1625 | packet_write_wait(); | |
1626 | } | |
8efc0c15 | 1627 | } |
1628 | ||
5260325f | 1629 | /* |
1630 | * The user does not exist or access is denied, | |
1631 | * but fake indication that authentication is needed. | |
1632 | */ | |
e7c0f9d5 | 1633 | void |
1634 | do_fake_authloop(char *user) | |
0183ea1c | 1635 | { |
5260325f | 1636 | int attempt = 0; |
1637 | ||
1638 | log("Faking authloop for illegal user %.200s from %.200s port %d", | |
1639 | user, | |
1640 | get_remote_ipaddr(), | |
1641 | get_remote_port()); | |
1642 | ||
1643 | /* Indicate that authentication is needed. */ | |
1644 | packet_start(SSH_SMSG_FAILURE); | |
1645 | packet_send(); | |
1646 | packet_write_wait(); | |
1647 | ||
aa3378df | 1648 | /* |
1649 | * Keep reading packets, and always respond with a failure. This is | |
1650 | * to avoid disclosing whether such a user really exists. | |
1651 | */ | |
5260325f | 1652 | for (attempt = 1;; attempt++) { |
aa3378df | 1653 | /* Read a packet. This will not return if the client disconnects. */ |
5260325f | 1654 | int plen; |
1655 | int type = packet_read(&plen); | |
e7c0f9d5 | 1656 | #ifdef SKEY |
5260325f | 1657 | int dlen; |
1658 | char *password, *skeyinfo; | |
95f1eccc | 1659 | /* Try to send a fake s/key challenge. */ |
1660 | if (options.skey_authentication == 1 && | |
5260325f | 1661 | (skeyinfo = skey_fake_keyinfo(user)) != NULL) { |
95f1eccc | 1662 | if (type == SSH_CMSG_AUTH_TIS) { |
1663 | packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE); | |
1664 | packet_put_string(skeyinfo, strlen(skeyinfo)); | |
1665 | packet_send(); | |
1666 | packet_write_wait(); | |
1667 | continue; | |
1668 | } else if (type == SSH_CMSG_AUTH_PASSWORD && | |
1669 | options.password_authentication && | |
1670 | (password = packet_get_string(&dlen)) != NULL && | |
1671 | dlen == 5 && | |
1672 | strncasecmp(password, "s/key", 5) == 0 ) { | |
1673 | packet_send_debug(skeyinfo); | |
1674 | } | |
5260325f | 1675 | } |
e7c0f9d5 | 1676 | #endif |
5260325f | 1677 | if (attempt > AUTH_FAIL_MAX) |
1678 | packet_disconnect(AUTH_FAIL_MSG, user); | |
1679 | ||
aa3378df | 1680 | /* |
1681 | * Send failure. This should be indistinguishable from a | |
1682 | * failed authentication. | |
1683 | */ | |
5260325f | 1684 | packet_start(SSH_SMSG_FAILURE); |
1685 | packet_send(); | |
1686 | packet_write_wait(); | |
1687 | } | |
1688 | /* NOTREACHED */ | |
1689 | abort(); | |
0183ea1c | 1690 | } |
1691 | ||
e7c0f9d5 | 1692 | |
5260325f | 1693 | /* |
1694 | * Remove local Xauthority file. | |
1695 | */ | |
6a17f9c2 | 1696 | static void |
1697 | xauthfile_cleanup_proc(void *ignore) | |
1698 | { | |
5260325f | 1699 | debug("xauthfile_cleanup_proc called"); |
6a17f9c2 | 1700 | |
5260325f | 1701 | if (xauthfile != NULL) { |
1702 | unlink(xauthfile); | |
1703 | xfree(xauthfile); | |
1704 | xauthfile = NULL; | |
1705 | } | |
6a17f9c2 | 1706 | } |
1707 | ||
5260325f | 1708 | /* |
1709 | * Prepares for an interactive session. This is called after the user has | |
1710 | * been successfully authenticated. During this message exchange, pseudo | |
1711 | * terminals are allocated, X11, TCP/IP, and authentication agent forwardings | |
1712 | * are requested, etc. | |
1713 | */ | |
1714 | void | |
1715 | do_authenticated(struct passwd * pw) | |
8efc0c15 | 1716 | { |
5260325f | 1717 | int type; |
1718 | int compression_level = 0, enable_compression_after_reply = 0; | |
1719 | int have_pty = 0, ptyfd = -1, ttyfd = -1, xauthfd = -1; | |
1720 | int row, col, xpixel, ypixel, screen; | |
1721 | char ttyname[64]; | |
1722 | char *command, *term = NULL, *display = NULL, *proto = NULL, | |
1723 | *data = NULL; | |
1724 | struct group *grp; | |
1725 | gid_t tty_gid; | |
1726 | mode_t tty_mode; | |
1727 | int n_bytes; | |
1728 | ||
aa3378df | 1729 | /* |
1730 | * Cancel the alarm we set to limit the time taken for | |
1731 | * authentication. | |
1732 | */ | |
5260325f | 1733 | alarm(0); |
1734 | ||
aa3378df | 1735 | /* |
1736 | * Inform the channel mechanism that we are the server side and that | |
1737 | * the client may request to connect to any port at all. (The user | |
1738 | * could do it anyway, and we wouldn\'t know what is permitted except | |
1739 | * by the client telling us, so we can equally well trust the client | |
1740 | * not to request anything bogus.) | |
1741 | */ | |
5260325f | 1742 | channel_permit_all_opens(); |
1743 | ||
aa3378df | 1744 | /* |
1745 | * We stay in this loop until the client requests to execute a shell | |
1746 | * or a command. | |
1747 | */ | |
5260325f | 1748 | while (1) { |
1749 | int plen, dlen; | |
1750 | ||
1751 | /* Get a packet from the client. */ | |
1752 | type = packet_read(&plen); | |
1753 | ||
1754 | /* Process the packet. */ | |
1755 | switch (type) { | |
1756 | case SSH_CMSG_REQUEST_COMPRESSION: | |
1757 | packet_integrity_check(plen, 4, type); | |
1758 | compression_level = packet_get_int(); | |
1759 | if (compression_level < 1 || compression_level > 9) { | |
1760 | packet_send_debug("Received illegal compression level %d.", | |
1761 | compression_level); | |
1762 | goto fail; | |
1763 | } | |
1764 | /* Enable compression after we have responded with SUCCESS. */ | |
1765 | enable_compression_after_reply = 1; | |
1766 | break; | |
1767 | ||
1768 | case SSH_CMSG_REQUEST_PTY: | |
1769 | if (no_pty_flag) { | |
1770 | debug("Allocating a pty not permitted for this authentication."); | |
1771 | goto fail; | |
1772 | } | |
1773 | if (have_pty) | |
1774 | packet_disconnect("Protocol error: you already have a pty."); | |
1775 | ||
1776 | debug("Allocating pty."); | |
1777 | ||
1778 | /* Allocate a pty and open it. */ | |
a408af76 | 1779 | if (!pty_allocate(&ptyfd, &ttyfd, ttyname, |
1780 | sizeof(ttyname))) { | |
5260325f | 1781 | error("Failed to allocate pty."); |
1782 | goto fail; | |
1783 | } | |
1784 | /* Determine the group to make the owner of the tty. */ | |
1785 | grp = getgrnam("tty"); | |
1786 | if (grp) { | |
1787 | tty_gid = grp->gr_gid; | |
1788 | tty_mode = S_IRUSR | S_IWUSR | S_IWGRP; | |
1789 | } else { | |
1790 | tty_gid = pw->pw_gid; | |
1791 | tty_mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH; | |
1792 | } | |
1793 | ||
1794 | /* Change ownership of the tty. */ | |
1795 | if (chown(ttyname, pw->pw_uid, tty_gid) < 0) | |
1796 | fatal("chown(%.100s, %d, %d) failed: %.100s", | |
1797 | ttyname, pw->pw_uid, tty_gid, strerror(errno)); | |
1798 | if (chmod(ttyname, tty_mode) < 0) | |
1799 | fatal("chmod(%.100s, 0%o) failed: %.100s", | |
1800 | ttyname, tty_mode, strerror(errno)); | |
1801 | ||
1802 | /* Get TERM from the packet. Note that the value may be of arbitrary length. */ | |
1803 | term = packet_get_string(&dlen); | |
1804 | packet_integrity_check(dlen, strlen(term), type); | |
1805 | /* packet_integrity_check(plen, 4 + dlen + 4*4 + n_bytes, type); */ | |
1806 | /* Remaining bytes */ | |
1807 | n_bytes = plen - (4 + dlen + 4 * 4); | |
1808 | ||
1809 | if (strcmp(term, "") == 0) | |
1810 | term = NULL; | |
1811 | ||
1812 | /* Get window size from the packet. */ | |
1813 | row = packet_get_int(); | |
1814 | col = packet_get_int(); | |
1815 | xpixel = packet_get_int(); | |
1816 | ypixel = packet_get_int(); | |
1817 | pty_change_window_size(ptyfd, row, col, xpixel, ypixel); | |
1818 | ||
1819 | /* Get tty modes from the packet. */ | |
1820 | tty_parse_modes(ttyfd, &n_bytes); | |
1821 | packet_integrity_check(plen, 4 + dlen + 4 * 4 + n_bytes, type); | |
1822 | ||
1823 | /* Indicate that we now have a pty. */ | |
1824 | have_pty = 1; | |
8946db53 | 1825 | |
1826 | #ifdef HAVE_LIBPAM | |
1827 | /* do the pam_open_session since we have the pty */ | |
1828 | do_pam_session(pw->pw_name,ttyname); | |
1829 | #endif /* HAVE_LIBPAM */ | |
1830 | ||
5260325f | 1831 | break; |
1832 | ||
1833 | case SSH_CMSG_X11_REQUEST_FORWARDING: | |
1834 | if (!options.x11_forwarding) { | |
1835 | packet_send_debug("X11 forwarding disabled in server configuration file."); | |
1836 | goto fail; | |
1837 | } | |
8efc0c15 | 1838 | #ifdef XAUTH_PATH |
5260325f | 1839 | if (no_x11_forwarding_flag) { |
1840 | packet_send_debug("X11 forwarding not permitted for this authentication."); | |
1841 | goto fail; | |
1842 | } | |
1843 | debug("Received request for X11 forwarding with auth spoofing."); | |
1844 | if (display) | |
1845 | packet_disconnect("Protocol error: X11 display already set."); | |
1846 | { | |
1847 | int proto_len, data_len; | |
1848 | proto = packet_get_string(&proto_len); | |
1849 | data = packet_get_string(&data_len); | |
1850 | packet_integrity_check(plen, 4 + proto_len + 4 + data_len + 4, type); | |
1851 | } | |
1852 | if (packet_get_protocol_flags() & SSH_PROTOFLAG_SCREEN_NUMBER) | |
1853 | screen = packet_get_int(); | |
1854 | else | |
1855 | screen = 0; | |
95f1eccc | 1856 | display = x11_create_display_inet(screen, options.x11_display_offset); |
5260325f | 1857 | if (!display) |
1858 | goto fail; | |
1859 | ||
1860 | /* Setup to always have a local .Xauthority. */ | |
1861 | xauthfile = xmalloc(MAXPATHLEN); | |
1862 | snprintf(xauthfile, MAXPATHLEN, "/tmp/XauthXXXXXX"); | |
1863 | ||
1864 | if ((xauthfd = mkstemp(xauthfile)) != -1) { | |
1865 | fchown(xauthfd, pw->pw_uid, pw->pw_gid); | |
1866 | close(xauthfd); | |
1867 | fatal_add_cleanup(xauthfile_cleanup_proc, NULL); | |
1868 | } else { | |
1869 | xfree(xauthfile); | |
1870 | xauthfile = NULL; | |
1871 | } | |
1872 | break; | |
8efc0c15 | 1873 | #else /* XAUTH_PATH */ |
5260325f | 1874 | packet_send_debug("No xauth program; cannot forward with spoofing."); |
1875 | goto fail; | |
8efc0c15 | 1876 | #endif /* XAUTH_PATH */ |
1877 | ||
5260325f | 1878 | case SSH_CMSG_AGENT_REQUEST_FORWARDING: |
1879 | if (no_agent_forwarding_flag) { | |
1880 | debug("Authentication agent forwarding not permitted for this authentication."); | |
1881 | goto fail; | |
1882 | } | |
1883 | debug("Received authentication agent forwarding request."); | |
1884 | auth_input_request_forwarding(pw); | |
1885 | break; | |
1886 | ||
1887 | case SSH_CMSG_PORT_FORWARD_REQUEST: | |
1888 | if (no_port_forwarding_flag) { | |
1889 | debug("Port forwarding not permitted for this authentication."); | |
1890 | goto fail; | |
1891 | } | |
1892 | debug("Received TCP/IP port forwarding request."); | |
1893 | channel_input_port_forward_request(pw->pw_uid == 0); | |
1894 | break; | |
1895 | ||
1896 | case SSH_CMSG_MAX_PACKET_SIZE: | |
1897 | if (packet_set_maxsize(packet_get_int()) < 0) | |
1898 | goto fail; | |
1899 | break; | |
1900 | ||
1901 | case SSH_CMSG_EXEC_SHELL: | |
1902 | /* Set interactive/non-interactive mode. */ | |
1903 | packet_set_interactive(have_pty || display != NULL, | |
1904 | options.keepalives); | |
1905 | ||
1906 | if (forced_command != NULL) | |
1907 | goto do_forced_command; | |
1908 | debug("Forking shell."); | |
1909 | packet_integrity_check(plen, 0, type); | |
1910 | if (have_pty) | |
1911 | do_exec_pty(NULL, ptyfd, ttyfd, ttyname, pw, term, display, proto, data); | |
1912 | else | |
1913 | do_exec_no_pty(NULL, pw, display, proto, data); | |
1914 | return; | |
1915 | ||
1916 | case SSH_CMSG_EXEC_CMD: | |
1917 | /* Set interactive/non-interactive mode. */ | |
1918 | packet_set_interactive(have_pty || display != NULL, | |
1919 | options.keepalives); | |
1920 | ||
1921 | if (forced_command != NULL) | |
1922 | goto do_forced_command; | |
1923 | /* Get command from the packet. */ | |
1924 | { | |
1925 | int dlen; | |
1926 | command = packet_get_string(&dlen); | |
1927 | debug("Executing command '%.500s'", command); | |
1928 | packet_integrity_check(plen, 4 + dlen, type); | |
1929 | } | |
1930 | if (have_pty) | |
1931 | do_exec_pty(command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data); | |
1932 | else | |
1933 | do_exec_no_pty(command, pw, display, proto, data); | |
1934 | xfree(command); | |
1935 | return; | |
1936 | ||
1937 | default: | |
aa3378df | 1938 | /* |
1939 | * Any unknown messages in this phase are ignored, | |
1940 | * and a failure message is returned. | |
1941 | */ | |
5260325f | 1942 | log("Unknown packet type received after authentication: %d", type); |
1943 | goto fail; | |
1944 | } | |
8efc0c15 | 1945 | |
5260325f | 1946 | /* The request was successfully processed. */ |
1947 | packet_start(SSH_SMSG_SUCCESS); | |
1948 | packet_send(); | |
1949 | packet_write_wait(); | |
8efc0c15 | 1950 | |
5260325f | 1951 | /* Enable compression now that we have replied if appropriate. */ |
1952 | if (enable_compression_after_reply) { | |
1953 | enable_compression_after_reply = 0; | |
1954 | packet_start_compression(compression_level); | |
1955 | } | |
1956 | continue; | |
8efc0c15 | 1957 | |
5260325f | 1958 | fail: |
1959 | /* The request failed. */ | |
1960 | packet_start(SSH_SMSG_FAILURE); | |
1961 | packet_send(); | |
1962 | packet_write_wait(); | |
1963 | continue; | |
8efc0c15 | 1964 | |
5260325f | 1965 | do_forced_command: |
aa3378df | 1966 | /* |
1967 | * There is a forced command specified for this login. | |
1968 | * Execute it. | |
1969 | */ | |
5260325f | 1970 | debug("Executing forced command: %.900s", forced_command); |
1971 | if (have_pty) | |
1972 | do_exec_pty(forced_command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data); | |
1973 | else | |
1974 | do_exec_no_pty(forced_command, pw, display, proto, data); | |
1975 | return; | |
1976 | } | |
1977 | } | |
8efc0c15 | 1978 | |
5260325f | 1979 | /* |
1980 | * This is called to fork and execute a command when we have no tty. This | |
1981 | * will call do_child from the child, and server_loop from the parent after | |
1982 | * setting up file descriptors and such. | |
1983 | */ | |
1984 | void | |
1985 | do_exec_no_pty(const char *command, struct passwd * pw, | |
1986 | const char *display, const char *auth_proto, | |
1987 | const char *auth_data) | |
1988 | { | |
1989 | int pid; | |
8efc0c15 | 1990 | |
1991 | #ifdef USE_PIPES | |
5260325f | 1992 | int pin[2], pout[2], perr[2]; |
1993 | /* Allocate pipes for communicating with the program. */ | |
1994 | if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0) | |
1995 | packet_disconnect("Could not create pipes: %.100s", | |
1996 | strerror(errno)); | |
8efc0c15 | 1997 | #else /* USE_PIPES */ |
5260325f | 1998 | int inout[2], err[2]; |
1999 | /* Uses socket pairs to communicate with the program. */ | |
2000 | if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 || | |
2001 | socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) | |
2002 | packet_disconnect("Could not create socket pairs: %.100s", | |
2003 | strerror(errno)); | |
8efc0c15 | 2004 | #endif /* USE_PIPES */ |
8efc0c15 | 2005 | |
5260325f | 2006 | setproctitle("%s@notty", pw->pw_name); |
8efc0c15 | 2007 | |
5260325f | 2008 | /* Fork the child. */ |
2009 | if ((pid = fork()) == 0) { | |
2010 | /* Child. Reinitialize the log since the pid has changed. */ | |
2011 | log_init(av0, options.log_level, options.log_facility, log_stderr); | |
2012 | ||
aa3378df | 2013 | /* |
2014 | * Create a new session and process group since the 4.4BSD | |
2015 | * setlogin() affects the entire process group. | |
2016 | */ | |
5260325f | 2017 | if (setsid() < 0) |
2018 | error("setsid failed: %.100s", strerror(errno)); | |
8efc0c15 | 2019 | |
2020 | #ifdef USE_PIPES | |
aa3378df | 2021 | /* |
2022 | * Redirect stdin. We close the parent side of the socket | |
2023 | * pair, and make the child side the standard input. | |
2024 | */ | |
5260325f | 2025 | close(pin[1]); |
2026 | if (dup2(pin[0], 0) < 0) | |
2027 | perror("dup2 stdin"); | |
2028 | close(pin[0]); | |
2029 | ||
2030 | /* Redirect stdout. */ | |
2031 | close(pout[0]); | |
2032 | if (dup2(pout[1], 1) < 0) | |
2033 | perror("dup2 stdout"); | |
2034 | close(pout[1]); | |
2035 | ||
2036 | /* Redirect stderr. */ | |
2037 | close(perr[0]); | |
2038 | if (dup2(perr[1], 2) < 0) | |
2039 | perror("dup2 stderr"); | |
2040 | close(perr[1]); | |
8efc0c15 | 2041 | #else /* USE_PIPES */ |
aa3378df | 2042 | /* |
2043 | * Redirect stdin, stdout, and stderr. Stdin and stdout will | |
2044 | * use the same socket, as some programs (particularly rdist) | |
2045 | * seem to depend on it. | |
2046 | */ | |
5260325f | 2047 | close(inout[1]); |
2048 | close(err[1]); | |
2049 | if (dup2(inout[0], 0) < 0) /* stdin */ | |
2050 | perror("dup2 stdin"); | |
2051 | if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */ | |
2052 | perror("dup2 stdout"); | |
2053 | if (dup2(err[0], 2) < 0) /* stderr */ | |
2054 | perror("dup2 stderr"); | |
8efc0c15 | 2055 | #endif /* USE_PIPES */ |
2056 | ||
5260325f | 2057 | /* Do processing for the child (exec command etc). */ |
2058 | do_child(command, pw, NULL, display, auth_proto, auth_data, NULL); | |
2059 | /* NOTREACHED */ | |
2060 | } | |
2061 | if (pid < 0) | |
2062 | packet_disconnect("fork failed: %.100s", strerror(errno)); | |
8efc0c15 | 2063 | #ifdef USE_PIPES |
5260325f | 2064 | /* We are the parent. Close the child sides of the pipes. */ |
2065 | close(pin[0]); | |
2066 | close(pout[1]); | |
2067 | close(perr[1]); | |
2068 | ||
2069 | /* Enter the interactive session. */ | |
2070 | server_loop(pid, pin[1], pout[0], perr[0]); | |
2071 | /* server_loop has closed pin[1], pout[1], and perr[1]. */ | |
8efc0c15 | 2072 | #else /* USE_PIPES */ |
5260325f | 2073 | /* We are the parent. Close the child sides of the socket pairs. */ |
2074 | close(inout[0]); | |
2075 | close(err[0]); | |
2076 | ||
aa3378df | 2077 | /* |
2078 | * Enter the interactive session. Note: server_loop must be able to | |
2079 | * handle the case that fdin and fdout are the same. | |
2080 | */ | |
5260325f | 2081 | server_loop(pid, inout[1], inout[1], err[1]); |
2082 | /* server_loop has closed inout[1] and err[1]. */ | |
8efc0c15 | 2083 | #endif /* USE_PIPES */ |
2084 | } | |
2085 | ||
5260325f | 2086 | struct pty_cleanup_context { |
2087 | const char *ttyname; | |
2088 | int pid; | |
8efc0c15 | 2089 | }; |
2090 | ||
5260325f | 2091 | /* |
2092 | * Function to perform cleanup if we get aborted abnormally (e.g., due to a | |
2093 | * dropped connection). | |
2094 | */ | |
2095 | void | |
2096 | pty_cleanup_proc(void *context) | |
8efc0c15 | 2097 | { |
5260325f | 2098 | struct pty_cleanup_context *cu = context; |
8efc0c15 | 2099 | |
5260325f | 2100 | debug("pty_cleanup_proc called"); |
8efc0c15 | 2101 | |
5260325f | 2102 | /* Record that the user has logged out. */ |
2103 | record_logout(cu->pid, cu->ttyname); | |
8efc0c15 | 2104 | |
5260325f | 2105 | /* Release the pseudo-tty. */ |
2106 | pty_release(cu->ttyname); | |
8efc0c15 | 2107 | } |
2108 | ||
5260325f | 2109 | /* |
2110 | * This is called to fork and execute a command when we have a tty. This | |
2111 | * will call do_child from the child, and server_loop from the parent after | |
2112 | * setting up file descriptors, controlling tty, updating wtmp, utmp, | |
2113 | * lastlog, and other such operations. | |
2114 | */ | |
2115 | void | |
2116 | do_exec_pty(const char *command, int ptyfd, int ttyfd, | |
2117 | const char *ttyname, struct passwd * pw, const char *term, | |
2118 | const char *display, const char *auth_proto, | |
2119 | const char *auth_data) | |
8efc0c15 | 2120 | { |
5260325f | 2121 | int pid, fdout; |
2122 | const char *hostname; | |
2123 | time_t last_login_time; | |
2124 | char buf[100], *time_string; | |
2125 | FILE *f; | |
2126 | char line[256]; | |
2127 | struct stat st; | |
2128 | int quiet_login; | |
2129 | struct sockaddr_in from; | |
2130 | int fromlen; | |
2131 | struct pty_cleanup_context cleanup_context; | |
2132 | ||
2133 | /* Get remote host name. */ | |
2134 | hostname = get_canonical_hostname(); | |
2135 | ||
aa3378df | 2136 | /* |
2137 | * Get the time when the user last logged in. Buf will be set to | |
2138 | * contain the hostname the last login was from. | |
2139 | */ | |
5260325f | 2140 | if (!options.use_login) { |
2141 | last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name, | |
2142 | buf, sizeof(buf)); | |
8efc0c15 | 2143 | } |
5260325f | 2144 | setproctitle("%s@%s", pw->pw_name, strrchr(ttyname, '/') + 1); |
2145 | ||
2146 | /* Fork the child. */ | |
2147 | if ((pid = fork()) == 0) { | |
2148 | pid = getpid(); | |
2149 | ||
2150 | /* Child. Reinitialize the log because the pid has | |
2151 | changed. */ | |
2152 | log_init(av0, options.log_level, options.log_facility, log_stderr); | |
2153 | ||
2154 | /* Close the master side of the pseudo tty. */ | |
2155 | close(ptyfd); | |
2156 | ||
2157 | /* Make the pseudo tty our controlling tty. */ | |
2158 | pty_make_controlling_tty(&ttyfd, ttyname); | |
2159 | ||
2160 | /* Redirect stdin from the pseudo tty. */ | |
2161 | if (dup2(ttyfd, fileno(stdin)) < 0) | |
2162 | error("dup2 stdin failed: %.100s", strerror(errno)); | |
2163 | ||
2164 | /* Redirect stdout to the pseudo tty. */ | |
2165 | if (dup2(ttyfd, fileno(stdout)) < 0) | |
2166 | error("dup2 stdin failed: %.100s", strerror(errno)); | |
2167 | ||
2168 | /* Redirect stderr to the pseudo tty. */ | |
2169 | if (dup2(ttyfd, fileno(stderr)) < 0) | |
2170 | error("dup2 stdin failed: %.100s", strerror(errno)); | |
2171 | ||
2172 | /* Close the extra descriptor for the pseudo tty. */ | |
2173 | close(ttyfd); | |
2174 | ||
aa3378df | 2175 | /* |
2176 | * Get IP address of client. This is needed because we want | |
2177 | * to record where the user logged in from. If the | |
2178 | * connection is not a socket, let the ip address be 0.0.0.0. | |
2179 | */ | |
5260325f | 2180 | memset(&from, 0, sizeof(from)); |
2181 | if (packet_get_connection_in() == packet_get_connection_out()) { | |
2182 | fromlen = sizeof(from); | |
2183 | if (getpeername(packet_get_connection_in(), | |
2184 | (struct sockaddr *) & from, &fromlen) < 0) { | |
2185 | debug("getpeername: %.100s", strerror(errno)); | |
2186 | fatal_cleanup(); | |
2187 | } | |
2188 | } | |
2189 | /* Record that there was a login on that terminal. */ | |
2190 | record_login(pid, ttyname, pw->pw_name, pw->pw_uid, hostname, | |
2191 | &from); | |
8efc0c15 | 2192 | |
5260325f | 2193 | /* Check if .hushlogin exists. */ |
2194 | snprintf(line, sizeof line, "%.200s/.hushlogin", pw->pw_dir); | |
2195 | quiet_login = stat(line, &st) >= 0; | |
e1a9c08d | 2196 | |
2197 | #ifdef HAVE_LIBPAM | |
5260325f | 2198 | /* output the results of the pamconv() */ |
2199 | if (!quiet_login && pamconv_msg != NULL) | |
2200 | fprintf(stderr, pamconv_msg); | |
e1a9c08d | 2201 | #endif |
8efc0c15 | 2202 | |
aa3378df | 2203 | /* |
2204 | * If the user has logged in before, display the time of last | |
2205 | * login. However, don't display anything extra if a command | |
2206 | * has been specified (so that ssh can be used to execute | |
2207 | * commands on a remote machine without users knowing they | |
2208 | * are going to another machine). Login(1) will do this for | |
2209 | * us as well, so check if login(1) is used | |
2210 | */ | |
5260325f | 2211 | if (command == NULL && last_login_time != 0 && !quiet_login && |
2212 | !options.use_login) { | |
2213 | /* Convert the date to a string. */ | |
2214 | time_string = ctime(&last_login_time); | |
2215 | /* Remove the trailing newline. */ | |
2216 | if (strchr(time_string, '\n')) | |
2217 | *strchr(time_string, '\n') = 0; | |
2218 | /* Display the last login time. Host if displayed | |
2219 | if known. */ | |
2220 | if (strcmp(buf, "") == 0) | |
2221 | printf("Last login: %s\r\n", time_string); | |
2222 | else | |
2223 | printf("Last login: %s from %s\r\n", time_string, buf); | |
2224 | } | |
aa3378df | 2225 | /* |
2226 | * Print /etc/motd unless a command was specified or printing | |
2227 | * it was disabled in server options or login(1) will be | |
2228 | * used. Note that some machines appear to print it in | |
2229 | * /etc/profile or similar. | |
2230 | */ | |
5260325f | 2231 | if (command == NULL && options.print_motd && !quiet_login && |
2232 | !options.use_login) { | |
2233 | /* Print /etc/motd if it exists. */ | |
2234 | f = fopen("/etc/motd", "r"); | |
2235 | if (f) { | |
2236 | while (fgets(line, sizeof(line), f)) | |
2237 | fputs(line, stdout); | |
2238 | fclose(f); | |
2239 | } | |
2240 | } | |
2241 | /* Do common processing for the child, such as execing the command. */ | |
2242 | do_child(command, pw, term, display, auth_proto, auth_data, ttyname); | |
2243 | /* NOTREACHED */ | |
8efc0c15 | 2244 | } |
5260325f | 2245 | if (pid < 0) |
2246 | packet_disconnect("fork failed: %.100s", strerror(errno)); | |
2247 | /* Parent. Close the slave side of the pseudo tty. */ | |
2248 | close(ttyfd); | |
2249 | ||
aa3378df | 2250 | /* |
2251 | * Create another descriptor of the pty master side for use as the | |
2252 | * standard input. We could use the original descriptor, but this | |
2253 | * simplifies code in server_loop. The descriptor is bidirectional. | |
2254 | */ | |
5260325f | 2255 | fdout = dup(ptyfd); |
2256 | if (fdout < 0) | |
2257 | packet_disconnect("dup failed: %.100s", strerror(errno)); | |
2258 | ||
aa3378df | 2259 | /* |
2260 | * Add a cleanup function to clear the utmp entry and record logout | |
2261 | * time in case we call fatal() (e.g., the connection gets closed). | |
2262 | */ | |
5260325f | 2263 | cleanup_context.pid = pid; |
2264 | cleanup_context.ttyname = ttyname; | |
2265 | fatal_add_cleanup(pty_cleanup_proc, (void *) &cleanup_context); | |
2266 | ||
2267 | /* Enter interactive session. */ | |
2268 | server_loop(pid, ptyfd, fdout, -1); | |
2269 | /* server_loop has not closed ptyfd and fdout. */ | |
2270 | ||
2271 | /* Cancel the cleanup function. */ | |
2272 | fatal_remove_cleanup(pty_cleanup_proc, (void *) &cleanup_context); | |
2273 | ||
2274 | /* Record that the user has logged out. */ | |
2275 | record_logout(pid, ttyname); | |
2276 | ||
2277 | /* Release the pseudo-tty. */ | |
2278 | pty_release(ttyname); | |
2279 | ||
aa3378df | 2280 | /* |
2281 | * Close the server side of the socket pairs. We must do this after | |
2282 | * the pty cleanup, so that another process doesn't get this pty | |
2283 | * while we're still cleaning up. | |
2284 | */ | |
5260325f | 2285 | close(ptyfd); |
2286 | close(fdout); | |
8efc0c15 | 2287 | } |
2288 | ||
5260325f | 2289 | /* |
2290 | * Sets the value of the given variable in the environment. If the variable | |
2291 | * already exists, its value is overriden. | |
2292 | */ | |
2293 | void | |
2294 | child_set_env(char ***envp, unsigned int *envsizep, const char *name, | |
2295 | const char *value) | |
8efc0c15 | 2296 | { |
5260325f | 2297 | unsigned int i, namelen; |
2298 | char **env; | |
2299 | ||
aa3378df | 2300 | /* |
2301 | * Find the slot where the value should be stored. If the variable | |
2302 | * already exists, we reuse the slot; otherwise we append a new slot | |
2303 | * at the end of the array, expanding if necessary. | |
2304 | */ | |
5260325f | 2305 | env = *envp; |
2306 | namelen = strlen(name); | |
2307 | for (i = 0; env[i]; i++) | |
2308 | if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=') | |
2309 | break; | |
2310 | if (env[i]) { | |
aa3378df | 2311 | /* Reuse the slot. */ |
5260325f | 2312 | xfree(env[i]); |
2313 | } else { | |
aa3378df | 2314 | /* New variable. Expand if necessary. */ |
5260325f | 2315 | if (i >= (*envsizep) - 1) { |
2316 | (*envsizep) += 50; | |
2317 | env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *)); | |
2318 | } | |
2319 | /* Need to set the NULL pointer at end of array beyond the new slot. */ | |
2320 | env[i + 1] = NULL; | |
8efc0c15 | 2321 | } |
2322 | ||
5260325f | 2323 | /* Allocate space and format the variable in the appropriate slot. */ |
2324 | env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1); | |
2325 | snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value); | |
8efc0c15 | 2326 | } |
2327 | ||
5260325f | 2328 | /* |
2329 | * Reads environment variables from the given file and adds/overrides them | |
2330 | * into the environment. If the file does not exist, this does nothing. | |
2331 | * Otherwise, it must consist of empty lines, comments (line starts with '#') | |
2332 | * and assignments of the form name=value. No other forms are allowed. | |
2333 | */ | |
2334 | void | |
2335 | read_environment_file(char ***env, unsigned int *envsize, | |
2336 | const char *filename) | |
8efc0c15 | 2337 | { |
5260325f | 2338 | FILE *f; |
2339 | char buf[4096]; | |
2340 | char *cp, *value; | |
2341 | ||
5260325f | 2342 | f = fopen(filename, "r"); |
2343 | if (!f) | |
2344 | return; | |
2345 | ||
5260325f | 2346 | while (fgets(buf, sizeof(buf), f)) { |
aa3378df | 2347 | for (cp = buf; *cp == ' ' || *cp == '\t'; cp++) |
2348 | ; | |
5260325f | 2349 | if (!*cp || *cp == '#' || *cp == '\n') |
2350 | continue; | |
5260325f | 2351 | if (strchr(cp, '\n')) |
2352 | *strchr(cp, '\n') = '\0'; | |
5260325f | 2353 | value = strchr(cp, '='); |
2354 | if (value == NULL) { | |
2355 | fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf); | |
2356 | continue; | |
2357 | } | |
aa3378df | 2358 | /* Replace the equals sign by nul, and advance value to the value string. */ |
5260325f | 2359 | *value = '\0'; |
2360 | value++; | |
5260325f | 2361 | child_set_env(env, envsize, cp, value); |
2362 | } | |
5260325f | 2363 | fclose(f); |
8efc0c15 | 2364 | } |
2365 | ||
5260325f | 2366 | /* |
2367 | * Performs common processing for the child, such as setting up the | |
2368 | * environment, closing extra file descriptors, setting the user and group | |
2369 | * ids, and executing the command or shell. | |
2370 | */ | |
2371 | void | |
2372 | do_child(const char *command, struct passwd * pw, const char *term, | |
2373 | const char *display, const char *auth_proto, | |
2374 | const char *auth_data, const char *ttyname) | |
8efc0c15 | 2375 | { |
5260325f | 2376 | const char *shell, *cp = NULL; |
2377 | char buf[256]; | |
2378 | FILE *f; | |
2379 | unsigned int envsize, i; | |
2380 | char **env; | |
2381 | extern char **environ; | |
2382 | struct stat st; | |
2383 | char *argv[10]; | |
8efc0c15 | 2384 | |
e1a9c08d | 2385 | #ifndef HAVE_LIBPAM /* pam_nologin handles this */ |
5260325f | 2386 | /* Check /etc/nologin. */ |
2387 | f = fopen("/etc/nologin", "r"); | |
2388 | if (f) { | |
2389 | /* /etc/nologin exists. Print its contents and exit. */ | |
2390 | while (fgets(buf, sizeof(buf), f)) | |
2391 | fputs(buf, stderr); | |
2392 | fclose(f); | |
2393 | if (pw->pw_uid != 0) | |
2394 | exit(254); | |
2395 | } | |
e35c1dc2 | 2396 | #endif /* HAVE_LIBPAM */ |
2397 | ||
2398 | #ifdef HAVE_SETLOGIN | |
5260325f | 2399 | /* Set login name in the kernel. */ |
2400 | if (setlogin(pw->pw_name) < 0) | |
2401 | error("setlogin failed: %s", strerror(errno)); | |
e35c1dc2 | 2402 | #endif /* HAVE_SETLOGIN */ |
8efc0c15 | 2403 | |
5260325f | 2404 | /* Set uid, gid, and groups. */ |
2405 | /* Login(1) does this as well, and it needs uid 0 for the "-h" | |
2406 | switch, so we let login(1) to this for us. */ | |
2407 | if (!options.use_login) { | |
2408 | if (getuid() == 0 || geteuid() == 0) { | |
2409 | if (setgid(pw->pw_gid) < 0) { | |
2410 | perror("setgid"); | |
2411 | exit(1); | |
2412 | } | |
2413 | /* Initialize the group list. */ | |
2414 | if (initgroups(pw->pw_name, pw->pw_gid) < 0) { | |
2415 | perror("initgroups"); | |
2416 | exit(1); | |
2417 | } | |
2418 | endgrent(); | |
2419 | ||
2420 | /* Permanently switch to the desired uid. */ | |
2421 | permanently_set_uid(pw->pw_uid); | |
2422 | } | |
2423 | if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid) | |
2424 | fatal("Failed to set uids to %d.", (int) pw->pw_uid); | |
2425 | } | |
aa3378df | 2426 | /* |
2427 | * Get the shell from the password data. An empty shell field is | |
2428 | * legal, and means /bin/sh. | |
2429 | */ | |
5260325f | 2430 | shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell; |
8efc0c15 | 2431 | |
2432 | #ifdef AFS | |
5260325f | 2433 | /* Try to get AFS tokens for the local cell. */ |
2434 | if (k_hasafs()) { | |
2435 | char cell[64]; | |
2436 | ||
2437 | if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0) | |
2438 | krb_afslog(cell, 0); | |
2439 | ||
2440 | krb_afslog(0, 0); | |
2441 | } | |
8efc0c15 | 2442 | #endif /* AFS */ |
5260325f | 2443 | |
aa3378df | 2444 | /* Initialize the environment. */ |
5260325f | 2445 | envsize = 100; |
2446 | env = xmalloc(envsize * sizeof(char *)); | |
2447 | env[0] = NULL; | |
2448 | ||
2449 | if (!options.use_login) { | |
2450 | /* Set basic environment. */ | |
2451 | child_set_env(&env, &envsize, "USER", pw->pw_name); | |
2452 | child_set_env(&env, &envsize, "LOGNAME", pw->pw_name); | |
2453 | child_set_env(&env, &envsize, "HOME", pw->pw_dir); | |
2454 | child_set_env(&env, &envsize, "PATH", _PATH_STDPATH); | |
2455 | ||
2456 | snprintf(buf, sizeof buf, "%.200s/%.50s", | |
2457 | _PATH_MAILDIR, pw->pw_name); | |
2458 | child_set_env(&env, &envsize, "MAIL", buf); | |
2459 | ||
2460 | /* Normal systems set SHELL by default. */ | |
2461 | child_set_env(&env, &envsize, "SHELL", shell); | |
2462 | } | |
5260325f | 2463 | if (getenv("TZ")) |
2464 | child_set_env(&env, &envsize, "TZ", getenv("TZ")); | |
2465 | ||
2466 | /* Set custom environment options from RSA authentication. */ | |
2467 | while (custom_environment) { | |
2468 | struct envstring *ce = custom_environment; | |
2469 | char *s = ce->s; | |
2470 | int i; | |
2471 | for (i = 0; s[i] != '=' && s[i]; i++); | |
2472 | if (s[i] == '=') { | |
2473 | s[i] = 0; | |
2474 | child_set_env(&env, &envsize, s, s + i + 1); | |
2475 | } | |
2476 | custom_environment = ce->next; | |
2477 | xfree(ce->s); | |
2478 | xfree(ce); | |
8efc0c15 | 2479 | } |
8efc0c15 | 2480 | |
5260325f | 2481 | snprintf(buf, sizeof buf, "%.50s %d %d", |
2482 | get_remote_ipaddr(), get_remote_port(), options.port); | |
2483 | child_set_env(&env, &envsize, "SSH_CLIENT", buf); | |
8efc0c15 | 2484 | |
5260325f | 2485 | if (ttyname) |
2486 | child_set_env(&env, &envsize, "SSH_TTY", ttyname); | |
5260325f | 2487 | if (term) |
2488 | child_set_env(&env, &envsize, "TERM", term); | |
5260325f | 2489 | if (display) |
2490 | child_set_env(&env, &envsize, "DISPLAY", display); | |
8efc0c15 | 2491 | |
2492 | #ifdef KRB4 | |
5260325f | 2493 | { |
2494 | extern char *ticket; | |
2495 | ||
2496 | if (ticket) | |
2497 | child_set_env(&env, &envsize, "KRBTKFILE", ticket); | |
2498 | } | |
8efc0c15 | 2499 | #endif /* KRB4 */ |
2500 | ||
bb0dd7f6 | 2501 | #ifdef HAVE_LIBPAM |
5260325f | 2502 | /* Pull in any environment variables that may have been set by PAM. */ |
2503 | { | |
2504 | char *equals, var_name[512], var_val[512]; | |
2505 | char **pam_env = pam_getenvlist((pam_handle_t *)pamh); | |
2506 | int i; | |
2507 | for(i = 0; pam_env && pam_env[i]; i++) { | |
2508 | equals = strstr(pam_env[i], "="); | |
2509 | if ((strlen(pam_env[i]) < (sizeof(var_name) - 1)) && (equals != NULL)) | |
2510 | { | |
9c7b6dfd | 2511 | debug("PAM environment: %s=%s", var_name, var_val); |
5260325f | 2512 | memset(var_name, '\0', sizeof(var_name)); |
2513 | memset(var_val, '\0', sizeof(var_val)); | |
2514 | strncpy(var_name, pam_env[i], equals - pam_env[i]); | |
2515 | strcpy(var_val, equals + 1); | |
2516 | child_set_env(&env, &envsize, var_name, var_val); | |
2517 | } | |
2518 | } | |
2519 | } | |
bb0dd7f6 | 2520 | #endif /* HAVE_LIBPAM */ |
2521 | ||
5260325f | 2522 | if (xauthfile) |
2523 | child_set_env(&env, &envsize, "XAUTHORITY", xauthfile); | |
2524 | ||
5260325f | 2525 | if (auth_get_socket_name() != NULL) |
2526 | child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME, | |
2527 | auth_get_socket_name()); | |
2528 | ||
aa3378df | 2529 | /* read $HOME/.ssh/environment. */ |
5260325f | 2530 | if (!options.use_login) { |
2531 | snprintf(buf, sizeof buf, "%.200s/.ssh/environment", pw->pw_dir); | |
2532 | read_environment_file(&env, &envsize, buf); | |
2533 | } | |
5260325f | 2534 | if (debug_flag) { |
aa3378df | 2535 | /* dump the environment */ |
5260325f | 2536 | fprintf(stderr, "Environment:\n"); |
2537 | for (i = 0; env[i]; i++) | |
2538 | fprintf(stderr, " %.200s\n", env[i]); | |
2539 | } | |
aa3378df | 2540 | /* |
2541 | * Close the connection descriptors; note that this is the child, and | |
2542 | * the server will still have the socket open, and it is important | |
2543 | * that we do not shutdown it. Note that the descriptors cannot be | |
2544 | * closed before building the environment, as we call | |
2545 | * get_remote_ipaddr there. | |
2546 | */ | |
5260325f | 2547 | if (packet_get_connection_in() == packet_get_connection_out()) |
2548 | close(packet_get_connection_in()); | |
2549 | else { | |
2550 | close(packet_get_connection_in()); | |
2551 | close(packet_get_connection_out()); | |
2552 | } | |
aa3378df | 2553 | /* |
2554 | * Close all descriptors related to channels. They will still remain | |
2555 | * open in the parent. | |
2556 | */ | |
2557 | /* XXX better use close-on-exec? -markus */ | |
5260325f | 2558 | channel_close_all(); |
2559 | ||
aa3378df | 2560 | /* |
2561 | * Close any extra file descriptors. Note that there may still be | |
2562 | * descriptors left by system functions. They will be closed later. | |
2563 | */ | |
5260325f | 2564 | endpwent(); |
2565 | endhostent(); | |
2566 | ||
aa3378df | 2567 | /* |
2568 | * Close any extra open file descriptors so that we don\'t have them | |
2569 | * hanging around in clients. Note that we want to do this after | |
2570 | * initgroups, because at least on Solaris 2.3 it leaves file | |
2571 | * descriptors open. | |
2572 | */ | |
5260325f | 2573 | for (i = 3; i < 64; i++) |
2574 | close(i); | |
2575 | ||
2576 | /* Change current directory to the user\'s home directory. */ | |
2577 | if (chdir(pw->pw_dir) < 0) | |
2578 | fprintf(stderr, "Could not chdir to home directory %s: %s\n", | |
2579 | pw->pw_dir, strerror(errno)); | |
2580 | ||
aa3378df | 2581 | /* |
2582 | * Must take new environment into use so that .ssh/rc, /etc/sshrc and | |
2583 | * xauth are run in the proper environment. | |
2584 | */ | |
5260325f | 2585 | environ = env; |
2586 | ||
aa3378df | 2587 | /* |
2588 | * Run $HOME/.ssh/rc, /etc/sshrc, or xauth (whichever is found first | |
2589 | * in this order). | |
2590 | */ | |
5260325f | 2591 | if (!options.use_login) { |
2592 | if (stat(SSH_USER_RC, &st) >= 0) { | |
2593 | if (debug_flag) | |
2594 | fprintf(stderr, "Running /bin/sh %s\n", SSH_USER_RC); | |
2595 | ||
2596 | f = popen("/bin/sh " SSH_USER_RC, "w"); | |
2597 | if (f) { | |
2598 | if (auth_proto != NULL && auth_data != NULL) | |
2599 | fprintf(f, "%s %s\n", auth_proto, auth_data); | |
2600 | pclose(f); | |
2601 | } else | |
2602 | fprintf(stderr, "Could not run %s\n", SSH_USER_RC); | |
2603 | } else if (stat(SSH_SYSTEM_RC, &st) >= 0) { | |
2604 | if (debug_flag) | |
2605 | fprintf(stderr, "Running /bin/sh %s\n", SSH_SYSTEM_RC); | |
2606 | ||
2607 | f = popen("/bin/sh " SSH_SYSTEM_RC, "w"); | |
2608 | if (f) { | |
2609 | if (auth_proto != NULL && auth_data != NULL) | |
2610 | fprintf(f, "%s %s\n", auth_proto, auth_data); | |
2611 | pclose(f); | |
2612 | } else | |
2613 | fprintf(stderr, "Could not run %s\n", SSH_SYSTEM_RC); | |
2614 | } | |
8efc0c15 | 2615 | #ifdef XAUTH_PATH |
5260325f | 2616 | else { |
aa3378df | 2617 | /* Add authority data to .Xauthority if appropriate. */ |
5260325f | 2618 | if (auth_proto != NULL && auth_data != NULL) { |
2619 | if (debug_flag) | |
2620 | fprintf(stderr, "Running %.100s add %.100s %.100s %.100s\n", | |
2621 | XAUTH_PATH, display, auth_proto, auth_data); | |
2622 | ||
2623 | f = popen(XAUTH_PATH " -q -", "w"); | |
2624 | if (f) { | |
2625 | fprintf(f, "add %s %s %s\n", display, auth_proto, auth_data); | |
2626 | fclose(f); | |
2627 | } else | |
2628 | fprintf(stderr, "Could not run %s -q -\n", XAUTH_PATH); | |
2629 | } | |
2630 | } | |
8efc0c15 | 2631 | #endif /* XAUTH_PATH */ |
2632 | ||
5260325f | 2633 | /* Get the last component of the shell name. */ |
2634 | cp = strrchr(shell, '/'); | |
2635 | if (cp) | |
2636 | cp++; | |
2637 | else | |
2638 | cp = shell; | |
2639 | } | |
aa3378df | 2640 | /* |
2641 | * If we have no command, execute the shell. In this case, the shell | |
2642 | * name to be passed in argv[0] is preceded by '-' to indicate that | |
2643 | * this is a login shell. | |
2644 | */ | |
5260325f | 2645 | if (!command) { |
2646 | if (!options.use_login) { | |
2647 | char buf[256]; | |
2648 | ||
aa3378df | 2649 | /* |
2650 | * Check for mail if we have a tty and it was enabled | |
2651 | * in server options. | |
2652 | */ | |
5260325f | 2653 | if (ttyname && options.check_mail) { |
2654 | char *mailbox; | |
2655 | struct stat mailstat; | |
2656 | mailbox = getenv("MAIL"); | |
2657 | if (mailbox != NULL) { | |
2658 | if (stat(mailbox, &mailstat) != 0 || mailstat.st_size == 0) | |
2659 | printf("No mail.\n"); | |
2660 | else if (mailstat.st_mtime < mailstat.st_atime) | |
2661 | printf("You have mail.\n"); | |
2662 | else | |
2663 | printf("You have new mail.\n"); | |
2664 | } | |
2665 | } | |
2666 | /* Start the shell. Set initial character to '-'. */ | |
2667 | buf[0] = '-'; | |
2668 | strncpy(buf + 1, cp, sizeof(buf) - 1); | |
2669 | buf[sizeof(buf) - 1] = 0; | |
2670 | ||
2671 | /* Execute the shell. */ | |
2672 | argv[0] = buf; | |
2673 | argv[1] = NULL; | |
2674 | execve(shell, argv, env); | |
2675 | ||
2676 | /* Executing the shell failed. */ | |
2677 | perror(shell); | |
2678 | exit(1); | |
2679 | ||
2680 | } else { | |
2681 | /* Launch login(1). */ | |
2682 | ||
2683 | execl(LOGIN_PROGRAM, "login", "-h", get_remote_ipaddr(), | |
2684 | "-p", "-f", "--", pw->pw_name, NULL); | |
2685 | ||
2686 | /* Login couldn't be executed, die. */ | |
2687 | ||
2688 | perror("login"); | |
2689 | exit(1); | |
2690 | } | |
2691 | } | |
aa3378df | 2692 | /* |
2693 | * Execute the command using the user's shell. This uses the -c | |
2694 | * option to execute the command. | |
2695 | */ | |
5260325f | 2696 | argv[0] = (char *) cp; |
2697 | argv[1] = "-c"; | |
2698 | argv[2] = (char *) command; | |
2699 | argv[3] = NULL; | |
2700 | execve(shell, argv, env); | |
2701 | perror(shell); | |
2702 | exit(1); | |
8efc0c15 | 2703 | } |