blob: a5cbbfc43c039cea640af82dbc5d493059c4c464 [file] [log] [blame]
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001/*
Damien Miller95def091999-11-25 00:26:21 +11002 * 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 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100012
13#include "includes.h"
Damien Millerf052aaf2000-01-22 19:47:21 +110014RCSID("$OpenBSD: sshd.c,v 1.80 2000/01/20 15:19:22 markus Exp $");
Damien Millerd4a8b7e1999-10-27 13:42:43 +100015
16#include "xmalloc.h"
17#include "rsa.h"
18#include "ssh.h"
19#include "pty.h"
20#include "packet.h"
21#include "buffer.h"
22#include "cipher.h"
23#include "mpaux.h"
24#include "servconf.h"
25#include "uidswap.h"
26#include "compat.h"
27
28#ifdef LIBWRAP
29#include <tcpd.h>
30#include <syslog.h>
31int allow_severity = LOG_INFO;
32int deny_severity = LOG_WARNING;
33#endif /* LIBWRAP */
34
35#ifndef O_NOCTTY
36#define O_NOCTTY 0
37#endif
38
Damien Millerd4a8b7e1999-10-27 13:42:43 +100039/* Local Xauthority file. */
Damien Miller5ce662a1999-11-11 17:57:39 +110040static char *xauthfile = NULL;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100041
42/* Server configuration options. */
43ServerOptions options;
44
45/* Name of the server configuration file. */
46char *config_file_name = SERVER_CONFIG_FILE;
47
Damien Miller34132e52000-01-14 15:45:46 +110048/*
49 * Flag indicating whether IPv4 or IPv6. This can be set on the command line.
50 * Default value is AF_UNSPEC means both IPv4 and IPv6.
51 */
Damien Miller7d80e342000-01-19 14:36:49 +110052#ifdef IPV4_DEFAULT
53int IPv4or6 = AF_INET;
54#else
Damien Miller34132e52000-01-14 15:45:46 +110055int IPv4or6 = AF_UNSPEC;
Damien Miller7d80e342000-01-19 14:36:49 +110056#endif
Damien Miller34132e52000-01-14 15:45:46 +110057
Damien Miller95def091999-11-25 00:26:21 +110058/*
59 * Debug mode flag. This can be set on the command line. If debug
60 * mode is enabled, extra debugging output will be sent to the system
61 * log, the daemon will not go to background, and will exit after processing
62 * the first connection.
63 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100064int debug_flag = 0;
65
66/* Flag indicating that the daemon is being started from inetd. */
67int inetd_flag = 0;
68
Damien Miller5ce662a1999-11-11 17:57:39 +110069/* debug goes to stderr unless inetd_flag is set */
70int log_stderr = 0;
71
Damien Millerd4a8b7e1999-10-27 13:42:43 +100072/* argv[0] without path. */
73char *av0;
74
75/* Saved arguments to main(). */
76char **saved_argv;
77
Damien Miller5428f641999-11-25 11:54:57 +110078/*
Damien Miller34132e52000-01-14 15:45:46 +110079 * The sockets that the server is listening; this is used in the SIGHUP
80 * signal handler.
Damien Miller5428f641999-11-25 11:54:57 +110081 */
Damien Miller34132e52000-01-14 15:45:46 +110082#define MAX_LISTEN_SOCKS 16
83int listen_socks[MAX_LISTEN_SOCKS];
84int num_listen_socks = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100085
Damien Miller5428f641999-11-25 11:54:57 +110086/*
87 * the client's version string, passed by sshd2 in compat mode. if != NULL,
88 * sshd will skip the version-number exchange
89 */
Damien Miller95def091999-11-25 00:26:21 +110090char *client_version_string = NULL;
91
92/* Flags set in auth-rsa from authorized_keys flags. These are set in auth-rsa.c. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100093int no_port_forwarding_flag = 0;
94int no_agent_forwarding_flag = 0;
95int no_x11_forwarding_flag = 0;
96int no_pty_flag = 0;
Damien Miller95def091999-11-25 00:26:21 +110097
98/* RSA authentication "command=" option. */
99char *forced_command = NULL;
100
101/* RSA authentication "environment=" options. */
102struct envstring *custom_environment = NULL;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000103
104/* Session id for the current session. */
105unsigned char session_id[16];
106
Damien Miller5428f641999-11-25 11:54:57 +1100107/*
108 * Any really sensitive data in the application is contained in this
109 * structure. The idea is that this structure could be locked into memory so
110 * that the pages do not get written into swap. However, there are some
111 * problems. The private key contains BIGNUMs, and we do not (in principle)
112 * have access to the internals of them, and locking just the structure is
113 * not very useful. Currently, memory locking is not implemented.
114 */
Damien Miller95def091999-11-25 00:26:21 +1100115struct {
116 RSA *private_key; /* Private part of server key. */
117 RSA *host_key; /* Private part of host key. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000118} sensitive_data;
119
Damien Miller5428f641999-11-25 11:54:57 +1100120/*
121 * Flag indicating whether the current session key has been used. This flag
122 * is set whenever the key is used, and cleared when the key is regenerated.
123 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000124int key_used = 0;
125
126/* This is set to true when SIGHUP is received. */
127int received_sighup = 0;
128
129/* Public side of the server key. This value is regenerated regularly with
130 the private key. */
131RSA *public_key;
132
133/* Prototypes for various functions defined later in this file. */
Damien Miller396691a2000-01-20 22:44:08 +1100134void do_ssh_kex();
135void do_authentication();
Damien Miller95def091999-11-25 00:26:21 +1100136void do_authloop(struct passwd * pw);
Damien Miller2ccf6611999-11-15 15:25:10 +1100137void do_fake_authloop(char *user);
Damien Miller95def091999-11-25 00:26:21 +1100138void do_authenticated(struct passwd * pw);
139void do_exec_pty(const char *command, int ptyfd, int ttyfd,
140 const char *ttyname, struct passwd * pw, const char *term,
141 const char *display, const char *auth_proto,
142 const char *auth_data);
143void do_exec_no_pty(const char *command, struct passwd * pw,
144 const char *display, const char *auth_proto,
145 const char *auth_data);
146void do_child(const char *command, struct passwd * pw, const char *term,
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000147 const char *display, const char *auth_proto,
148 const char *auth_data, const char *ttyname);
Damien Miller2ccf6611999-11-15 15:25:10 +1100149
Damien Miller95def091999-11-25 00:26:21 +1100150/*
Damien Miller34132e52000-01-14 15:45:46 +1100151 * Close all listening sockets
152 */
153void
154close_listen_socks(void)
155{
156 int i;
157 for (i = 0; i < num_listen_socks; i++)
158 close(listen_socks[i]);
159 num_listen_socks = -1;
160}
161
162/*
Damien Miller95def091999-11-25 00:26:21 +1100163 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
164 * the effect is to reread the configuration file (and to regenerate
165 * the server key).
166 */
167void
168sighup_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000169{
Damien Miller95def091999-11-25 00:26:21 +1100170 received_sighup = 1;
171 signal(SIGHUP, sighup_handler);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000172}
173
Damien Miller95def091999-11-25 00:26:21 +1100174/*
175 * Called from the main program after receiving SIGHUP.
176 * Restarts the server.
177 */
178void
179sighup_restart()
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000180{
Damien Miller95def091999-11-25 00:26:21 +1100181 log("Received SIGHUP; restarting.");
Damien Miller34132e52000-01-14 15:45:46 +1100182 close_listen_socks();
Damien Miller95def091999-11-25 00:26:21 +1100183 execv(saved_argv[0], saved_argv);
184 log("RESTART FAILED: av0='%s', error: %s.", av0, strerror(errno));
185 exit(1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000186}
187
Damien Miller95def091999-11-25 00:26:21 +1100188/*
189 * Generic signal handler for terminating signals in the master daemon.
190 * These close the listen socket; not closing it seems to cause "Address
191 * already in use" problems on some machines, which is inconvenient.
192 */
193void
194sigterm_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000195{
Damien Miller95def091999-11-25 00:26:21 +1100196 log("Received signal %d; terminating.", sig);
Damien Miller34132e52000-01-14 15:45:46 +1100197 close_listen_socks();
Damien Miller95def091999-11-25 00:26:21 +1100198 exit(255);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000199}
200
Damien Miller95def091999-11-25 00:26:21 +1100201/*
202 * SIGCHLD handler. This is called whenever a child dies. This will then
203 * reap any zombies left by exited c.
204 */
205void
206main_sigchld_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000207{
Damien Miller95def091999-11-25 00:26:21 +1100208 int save_errno = errno;
209 int status;
Damien Miller431f66b1999-11-21 18:31:57 +1100210
Damien Miller95def091999-11-25 00:26:21 +1100211 while (waitpid(-1, &status, WNOHANG) > 0)
212 ;
Damien Miller431f66b1999-11-21 18:31:57 +1100213
Damien Miller95def091999-11-25 00:26:21 +1100214 signal(SIGCHLD, main_sigchld_handler);
215 errno = save_errno;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000216}
217
Damien Miller95def091999-11-25 00:26:21 +1100218/*
219 * Signal handler for the alarm after the login grace period has expired.
220 */
221void
222grace_alarm_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000223{
Damien Miller95def091999-11-25 00:26:21 +1100224 /* Close the connection. */
225 packet_close();
226
227 /* Log error and exit. */
228 fatal("Timeout before authentication for %s.", get_remote_ipaddr());
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000229}
230
Damien Miller95def091999-11-25 00:26:21 +1100231/*
232 * convert ssh auth msg type into description
233 */
234char *
235get_authname(int type)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000236{
Damien Miller95def091999-11-25 00:26:21 +1100237 switch (type) {
238 case SSH_CMSG_AUTH_PASSWORD:
239 return "password";
240 case SSH_CMSG_AUTH_RSA:
241 return "rsa";
242 case SSH_CMSG_AUTH_RHOSTS_RSA:
243 return "rhosts-rsa";
244 case SSH_CMSG_AUTH_RHOSTS:
245 return "rhosts";
246#ifdef KRB4
247 case SSH_CMSG_AUTH_KERBEROS:
248 return "kerberos";
249#endif
250#ifdef SKEY
251 case SSH_CMSG_AUTH_TIS_RESPONSE:
252 return "s/key";
253#endif
254 }
255 fatal("get_authname: unknown auth %d: internal error", type);
256 return NULL;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000257}
258
Damien Miller95def091999-11-25 00:26:21 +1100259/*
260 * Signal handler for the key regeneration alarm. Note that this
261 * alarm only occurs in the daemon waiting for connections, and it does not
262 * do anything with the private key or random state before forking.
263 * Thus there should be no concurrency control/asynchronous execution
264 * problems.
265 */
266void
267key_regeneration_alarm(int sig)
268{
269 int save_errno = errno;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000270
Damien Miller95def091999-11-25 00:26:21 +1100271 /* Check if we should generate a new key. */
272 if (key_used) {
273 /* This should really be done in the background. */
274 log("Generating new %d bit RSA key.", options.server_key_bits);
275
276 if (sensitive_data.private_key != NULL)
277 RSA_free(sensitive_data.private_key);
278 sensitive_data.private_key = RSA_new();
279
280 if (public_key != NULL)
281 RSA_free(public_key);
282 public_key = RSA_new();
283
284 rsa_generate_key(sensitive_data.private_key, public_key,
285 options.server_key_bits);
286 arc4random_stir();
287 key_used = 0;
288 log("RSA key generation complete.");
289 }
290 /* Reschedule the alarm. */
291 signal(SIGALRM, key_regeneration_alarm);
292 alarm(options.key_regeneration_time);
293 errno = save_errno;
294}
295
296/*
297 * Main program for the daemon.
298 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000299int
300main(int ac, char **av)
301{
Damien Miller95def091999-11-25 00:26:21 +1100302 extern char *optarg;
303 extern int optind;
Damien Miller34132e52000-01-14 15:45:46 +1100304 int opt, sock_in = 0, sock_out = 0, newsock, i, fdsetsz, pid, on = 1;
305 socklen_t fromlen;
Damien Miller95def091999-11-25 00:26:21 +1100306 int remote_major, remote_minor;
307 int silentrsa = 0;
Damien Miller34132e52000-01-14 15:45:46 +1100308 fd_set *fdset;
309 struct sockaddr_storage from;
Damien Miller95def091999-11-25 00:26:21 +1100310 char buf[100]; /* Must not be larger than remote_version. */
311 char remote_version[100]; /* Must be at least as big as buf. */
312 const char *remote_ip;
313 int remote_port;
314 char *comment;
315 FILE *f;
316 struct linger linger;
Damien Miller34132e52000-01-14 15:45:46 +1100317 struct addrinfo *ai;
318 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
319 int listen_sock, maxfd;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000320
Damien Miller95def091999-11-25 00:26:21 +1100321 /* Save argv[0]. */
322 saved_argv = av;
323 if (strchr(av[0], '/'))
324 av0 = strrchr(av[0], '/') + 1;
325 else
326 av0 = av[0];
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000327
Damien Miller95def091999-11-25 00:26:21 +1100328 /* Initialize configuration options to their default values. */
329 initialize_server_options(&options);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000330
Damien Miller95def091999-11-25 00:26:21 +1100331 /* Parse command-line arguments. */
Damien Miller34132e52000-01-14 15:45:46 +1100332 while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:diqQ46")) != EOF) {
Damien Miller95def091999-11-25 00:26:21 +1100333 switch (opt) {
Damien Miller34132e52000-01-14 15:45:46 +1100334 case '4':
335 IPv4or6 = AF_INET;
336 break;
337 case '6':
338 IPv4or6 = AF_INET6;
339 break;
Damien Miller95def091999-11-25 00:26:21 +1100340 case 'f':
341 config_file_name = optarg;
342 break;
343 case 'd':
344 debug_flag = 1;
345 options.log_level = SYSLOG_LEVEL_DEBUG;
346 break;
347 case 'i':
348 inetd_flag = 1;
349 break;
350 case 'Q':
351 silentrsa = 1;
352 break;
353 case 'q':
354 options.log_level = SYSLOG_LEVEL_QUIET;
355 break;
356 case 'b':
357 options.server_key_bits = atoi(optarg);
358 break;
359 case 'p':
Damien Miller34132e52000-01-14 15:45:46 +1100360 options.ports_from_cmdline = 1;
361 if (options.num_ports >= MAX_PORTS)
362 fatal("too many ports.\n");
363 options.ports[options.num_ports++] = atoi(optarg);
Damien Miller95def091999-11-25 00:26:21 +1100364 break;
365 case 'g':
366 options.login_grace_time = atoi(optarg);
367 break;
368 case 'k':
369 options.key_regeneration_time = atoi(optarg);
370 break;
371 case 'h':
372 options.host_key_file = optarg;
373 break;
374 case 'V':
375 client_version_string = optarg;
376 /* only makes sense with inetd_flag, i.e. no listen() */
377 inetd_flag = 1;
378 break;
379 case '?':
380 default:
381 fprintf(stderr, "sshd version %s\n", SSH_VERSION);
Damien Millerd00d1611999-12-29 10:17:09 +1100382#ifdef RSAREF
383 fprintf(stderr, "Compiled with RSAref.\n");
384#endif
Damien Miller95def091999-11-25 00:26:21 +1100385 fprintf(stderr, "Usage: %s [options]\n", av0);
386 fprintf(stderr, "Options:\n");
Damien Miller5428f641999-11-25 11:54:57 +1100387 fprintf(stderr, " -f file Configuration file (default %s)\n", SERVER_CONFIG_FILE);
Damien Miller95def091999-11-25 00:26:21 +1100388 fprintf(stderr, " -d Debugging mode\n");
389 fprintf(stderr, " -i Started from inetd\n");
390 fprintf(stderr, " -q Quiet (no logging)\n");
391 fprintf(stderr, " -p port Listen on the specified port (default: 22)\n");
392 fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n");
393 fprintf(stderr, " -g seconds Grace period for authentication (default: 300)\n");
394 fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n");
395 fprintf(stderr, " -h file File from which to read host key (default: %s)\n",
Damien Miller34132e52000-01-14 15:45:46 +1100396 HOST_KEY_FILE);
397 fprintf(stderr, " -4 Use IPv4 only\n");
398 fprintf(stderr, " -6 Use IPv6 only\n");
Damien Miller95def091999-11-25 00:26:21 +1100399 exit(1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000400 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000401 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000402
Damien Miller34132e52000-01-14 15:45:46 +1100403 /*
404 * Force logging to stderr until we have loaded the private host
405 * key (unless started from inetd)
406 */
407 log_init(av0,
408 options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
409 options.log_facility == -1 ? SYSLOG_FACILITY_AUTH : options.log_facility,
410 !inetd_flag);
411
Damien Miller95def091999-11-25 00:26:21 +1100412 /* check if RSA support exists */
413 if (rsa_alive() == 0) {
414 if (silentrsa == 0)
415 printf("sshd: no RSA support in libssl and libcrypto -- exiting. See ssl(8)\n");
416 log("no RSA support in libssl and libcrypto -- exiting. See ssl(8)");
417 exit(1);
418 }
419 /* Read server configuration options from the configuration file. */
420 read_server_config(&options, config_file_name);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000421
Damien Miller95def091999-11-25 00:26:21 +1100422 /* Fill in default values for those options not explicitly set. */
423 fill_default_server_options(&options);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000424
Damien Miller95def091999-11-25 00:26:21 +1100425 /* Check certain values for sanity. */
426 if (options.server_key_bits < 512 ||
427 options.server_key_bits > 32768) {
428 fprintf(stderr, "Bad server key size.\n");
429 exit(1);
430 }
Damien Miller95def091999-11-25 00:26:21 +1100431 /* Check that there are no remaining arguments. */
432 if (optind < ac) {
433 fprintf(stderr, "Extra argument %s.\n", av[optind]);
434 exit(1);
435 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000436
Damien Miller95def091999-11-25 00:26:21 +1100437 debug("sshd version %.100s", SSH_VERSION);
Damien Miller2ccf6611999-11-15 15:25:10 +1100438
Damien Miller95def091999-11-25 00:26:21 +1100439 sensitive_data.host_key = RSA_new();
440 errno = 0;
441 /* Load the host key. It must have empty passphrase. */
442 if (!load_private_key(options.host_key_file, "",
443 sensitive_data.host_key, &comment)) {
444 error("Could not load host key: %.200s: %.100s",
445 options.host_key_file, strerror(errno));
446 exit(1);
447 }
448 xfree(comment);
449
450 /* Initialize the log (it is reinitialized below in case we
451 forked). */
452 if (debug_flag && !inetd_flag)
453 log_stderr = 1;
454 log_init(av0, options.log_level, options.log_facility, log_stderr);
455
456 /* If not in debugging mode, and not started from inetd,
457 disconnect from the controlling terminal, and fork. The
458 original process exits. */
459 if (!debug_flag && !inetd_flag) {
460#ifdef TIOCNOTTY
461 int fd;
462#endif /* TIOCNOTTY */
463 if (daemon(0, 0) < 0)
464 fatal("daemon() failed: %.200s", strerror(errno));
465
466 /* Disconnect from the controlling tty. */
467#ifdef TIOCNOTTY
468 fd = open("/dev/tty", O_RDWR | O_NOCTTY);
469 if (fd >= 0) {
470 (void) ioctl(fd, TIOCNOTTY, NULL);
471 close(fd);
472 }
473#endif /* TIOCNOTTY */
474 }
475 /* Reinitialize the log (because of the fork above). */
476 log_init(av0, options.log_level, options.log_facility, log_stderr);
477
478 /* Check that server and host key lengths differ sufficiently.
479 This is necessary to make double encryption work with rsaref.
480 Oh, I hate software patents. I dont know if this can go? Niels */
481 if (options.server_key_bits >
482 BN_num_bits(sensitive_data.host_key->n) - SSH_KEY_BITS_RESERVED &&
483 options.server_key_bits <
484 BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) {
485 options.server_key_bits =
486 BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED;
487 debug("Forcing server key to %d bits to make it differ from host key.",
488 options.server_key_bits);
489 }
490 /* Do not display messages to stdout in RSA code. */
491 rsa_set_verbose(0);
492
493 /* Initialize the random number generator. */
494 arc4random_stir();
495
496 /* Chdir to the root directory so that the current disk can be
497 unmounted if desired. */
498 chdir("/");
499
500 /* Close connection cleanly after attack. */
501 cipher_attack_detected = packet_disconnect;
502
503 /* Start listening for a socket, unless started from inetd. */
504 if (inetd_flag) {
505 int s1, s2;
506 s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */
507 s2 = dup(s1);
508 sock_in = dup(0);
509 sock_out = dup(1);
510 /* We intentionally do not close the descriptors 0, 1, and 2
511 as our code for setting the descriptors won\'t work
512 if ttyfd happens to be one of those. */
513 debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
514
515 public_key = RSA_new();
516 sensitive_data.private_key = RSA_new();
517
518 log("Generating %d bit RSA key.", options.server_key_bits);
519 rsa_generate_key(sensitive_data.private_key, public_key,
520 options.server_key_bits);
521 arc4random_stir();
522 log("RSA key generation complete.");
523 } else {
Damien Miller34132e52000-01-14 15:45:46 +1100524 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
525 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
526 continue;
527 if (num_listen_socks >= MAX_LISTEN_SOCKS)
528 fatal("Too many listen sockets. "
529 "Enlarge MAX_LISTEN_SOCKS");
530 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
531 ntop, sizeof(ntop), strport, sizeof(strport),
532 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
533 error("getnameinfo failed");
534 continue;
535 }
536 /* Create socket for listening. */
537 listen_sock = socket(ai->ai_family, SOCK_STREAM, 0);
538 if (listen_sock < 0) {
539 /* kernel may not support ipv6 */
540 verbose("socket: %.100s", strerror(errno));
541 continue;
542 }
543 if (fcntl(listen_sock, F_SETFL, O_NONBLOCK) < 0) {
544 error("listen_sock O_NONBLOCK: %s", strerror(errno));
545 close(listen_sock);
546 continue;
547 }
548 /*
549 * Set socket options. We try to make the port
550 * reusable and have it close as fast as possible
551 * without waiting in unnecessary wait states on
552 * close.
553 */
554 setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
555 (void *) &on, sizeof(on));
556 linger.l_onoff = 1;
557 linger.l_linger = 5;
558 setsockopt(listen_sock, SOL_SOCKET, SO_LINGER,
559 (void *) &linger, sizeof(linger));
Damien Miller95def091999-11-25 00:26:21 +1100560
Damien Miller34132e52000-01-14 15:45:46 +1100561 debug("Bind to port %s on %s.", strport, ntop);
Damien Miller95def091999-11-25 00:26:21 +1100562
Damien Miller34132e52000-01-14 15:45:46 +1100563 /* Bind the socket to the desired port. */
564 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
565 error("Bind to port %s on %s failed: %.200s.",
566 strport, ntop, strerror(errno));
567 close(listen_sock);
568 continue;
569 }
570 listen_socks[num_listen_socks] = listen_sock;
571 num_listen_socks++;
Damien Miller95def091999-11-25 00:26:21 +1100572
Damien Miller34132e52000-01-14 15:45:46 +1100573 /* Start listening on the port. */
574 log("Server listening on %s port %s.", ntop, strport);
575 if (listen(listen_sock, 5) < 0)
576 fatal("listen: %.100s", strerror(errno));
577
Damien Miller95def091999-11-25 00:26:21 +1100578 }
Damien Miller34132e52000-01-14 15:45:46 +1100579 freeaddrinfo(options.listen_addrs);
580
581 if (!num_listen_socks)
582 fatal("Cannot bind any address.");
583
Damien Miller95def091999-11-25 00:26:21 +1100584 if (!debug_flag) {
Damien Miller5428f641999-11-25 11:54:57 +1100585 /*
586 * Record our pid in /etc/sshd_pid to make it easier
587 * to kill the correct sshd. We don\'t want to do
588 * this before the bind above because the bind will
589 * fail if there already is a daemon, and this will
590 * overwrite any old pid in the file.
591 */
Damien Miller95def091999-11-25 00:26:21 +1100592 f = fopen(SSH_DAEMON_PID_FILE, "w");
593 if (f) {
594 fprintf(f, "%u\n", (unsigned int) getpid());
595 fclose(f);
596 }
597 }
598
Damien Miller95def091999-11-25 00:26:21 +1100599 public_key = RSA_new();
600 sensitive_data.private_key = RSA_new();
601
602 log("Generating %d bit RSA key.", options.server_key_bits);
603 rsa_generate_key(sensitive_data.private_key, public_key,
604 options.server_key_bits);
605 arc4random_stir();
606 log("RSA key generation complete.");
607
608 /* Schedule server key regeneration alarm. */
609 signal(SIGALRM, key_regeneration_alarm);
610 alarm(options.key_regeneration_time);
611
612 /* Arrange to restart on SIGHUP. The handler needs listen_sock. */
613 signal(SIGHUP, sighup_handler);
614 signal(SIGTERM, sigterm_handler);
615 signal(SIGQUIT, sigterm_handler);
616
617 /* Arrange SIGCHLD to be caught. */
618 signal(SIGCHLD, main_sigchld_handler);
619
Damien Miller34132e52000-01-14 15:45:46 +1100620 /* setup fd set for listen */
621 maxfd = 0;
622 for (i = 0; i < num_listen_socks; i++)
623 if (listen_socks[i] > maxfd)
624 maxfd = listen_socks[i];
625 fdsetsz = howmany(maxfd, NFDBITS) * sizeof(fd_mask);
626 fdset = (fd_set *)xmalloc(fdsetsz);
627
Damien Miller5428f641999-11-25 11:54:57 +1100628 /*
629 * Stay listening for connections until the system crashes or
630 * the daemon is killed with a signal.
631 */
Damien Miller95def091999-11-25 00:26:21 +1100632 for (;;) {
633 if (received_sighup)
634 sighup_restart();
Damien Miller34132e52000-01-14 15:45:46 +1100635 /* Wait in select until there is a connection. */
636 memset(fdset, 0, fdsetsz);
637 for (i = 0; i < num_listen_socks; i++)
638 FD_SET(listen_socks[i], fdset);
639 if (select(maxfd + 1, fdset, NULL, NULL, NULL) < 0) {
640 if (errno != EINTR)
641 error("select: %.100s", strerror(errno));
Damien Miller50945fa1999-12-09 10:31:37 +1100642 continue;
Damien Miller34132e52000-01-14 15:45:46 +1100643 }
644 for (i = 0; i < num_listen_socks; i++) {
645 if (!FD_ISSET(listen_socks[i], fdset))
Damien Miller95def091999-11-25 00:26:21 +1100646 continue;
Damien Miller34132e52000-01-14 15:45:46 +1100647 fromlen = sizeof(from);
648 newsock = accept(listen_socks[i], (struct sockaddr *)&from,
649 &fromlen);
650 if (newsock < 0) {
651 if (errno != EINTR && errno != EWOULDBLOCK)
652 error("accept: %.100s", strerror(errno));
653 continue;
654 }
655 if (fcntl(newsock, F_SETFL, 0) < 0) {
656 error("newsock del O_NONBLOCK: %s", strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +1100657 continue;
658 }
Damien Miller5428f641999-11-25 11:54:57 +1100659 /*
660 * Got connection. Fork a child to handle it, unless
661 * we are in debugging mode.
662 */
Damien Miller95def091999-11-25 00:26:21 +1100663 if (debug_flag) {
Damien Miller5428f641999-11-25 11:54:57 +1100664 /*
665 * In debugging mode. Close the listening
666 * socket, and start processing the
667 * connection without forking.
668 */
Damien Miller95def091999-11-25 00:26:21 +1100669 debug("Server will not fork when running in debugging mode.");
Damien Miller34132e52000-01-14 15:45:46 +1100670 close_listen_socks();
Damien Miller95def091999-11-25 00:26:21 +1100671 sock_in = newsock;
672 sock_out = newsock;
673 pid = getpid();
674 break;
675 } else {
Damien Miller5428f641999-11-25 11:54:57 +1100676 /*
677 * Normal production daemon. Fork, and have
678 * the child process the connection. The
679 * parent continues listening.
680 */
Damien Miller95def091999-11-25 00:26:21 +1100681 if ((pid = fork()) == 0) {
Damien Miller5428f641999-11-25 11:54:57 +1100682 /*
683 * Child. Close the listening socket, and start using the
684 * accepted socket. Reinitialize logging (since our pid has
685 * changed). We break out of the loop to handle the connection.
686 */
Damien Miller34132e52000-01-14 15:45:46 +1100687 close_listen_socks();
Damien Miller95def091999-11-25 00:26:21 +1100688 sock_in = newsock;
689 sock_out = newsock;
690 log_init(av0, options.log_level, options.log_facility, log_stderr);
691 break;
692 }
693 }
694
695 /* Parent. Stay in the loop. */
696 if (pid < 0)
697 error("fork: %.100s", strerror(errno));
698 else
699 debug("Forked child %d.", pid);
700
701 /* Mark that the key has been used (it was "given" to the child). */
702 key_used = 1;
703
704 arc4random_stir();
705
706 /* Close the new socket (the child is now taking care of it). */
707 close(newsock);
Damien Miller34132e52000-01-14 15:45:46 +1100708 } /* for (i = 0; i < num_listen_socks; i++) */
709 /* child process check (or debug mode) */
710 if (num_listen_socks < 0)
711 break;
Damien Miller95def091999-11-25 00:26:21 +1100712 }
713 }
714
715 /* This is the child processing a new connection. */
716
Damien Miller5428f641999-11-25 11:54:57 +1100717 /*
718 * Disable the key regeneration alarm. We will not regenerate the
719 * key since we are no longer in a position to give it to anyone. We
720 * will not restart on SIGHUP since it no longer makes sense.
721 */
Damien Miller95def091999-11-25 00:26:21 +1100722 alarm(0);
723 signal(SIGALRM, SIG_DFL);
724 signal(SIGHUP, SIG_DFL);
725 signal(SIGTERM, SIG_DFL);
726 signal(SIGQUIT, SIG_DFL);
727 signal(SIGCHLD, SIG_DFL);
728
Damien Miller5428f641999-11-25 11:54:57 +1100729 /*
730 * Set socket options for the connection. We want the socket to
731 * close as fast as possible without waiting for anything. If the
732 * connection is not a socket, these will do nothing.
733 */
734 /* setsockopt(sock_in, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
Damien Miller95def091999-11-25 00:26:21 +1100735 linger.l_onoff = 1;
736 linger.l_linger = 5;
737 setsockopt(sock_in, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger));
738
Damien Miller5428f641999-11-25 11:54:57 +1100739 /*
740 * Register our connection. This turns encryption off because we do
741 * not have a key.
742 */
Damien Miller95def091999-11-25 00:26:21 +1100743 packet_set_connection(sock_in, sock_out);
744
745 remote_port = get_remote_port();
746 remote_ip = get_remote_ipaddr();
747
748 /* Check whether logins are denied from this host. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000749#ifdef LIBWRAP
Damien Miller34132e52000-01-14 15:45:46 +1100750 /* XXX LIBWRAP noes not know about IPv6 */
Damien Miller95def091999-11-25 00:26:21 +1100751 {
752 struct request_info req;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000753
Damien Miller95def091999-11-25 00:26:21 +1100754 request_init(&req, RQ_DAEMON, av0, RQ_FILE, sock_in, NULL);
755 fromhost(&req);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000756
Damien Miller95def091999-11-25 00:26:21 +1100757 if (!hosts_access(&req)) {
758 close(sock_in);
759 close(sock_out);
760 refuse(&req);
761 }
Damien Miller34132e52000-01-14 15:45:46 +1100762/*XXX IPv6 verbose("Connection from %.500s port %d", eval_client(&req), remote_port); */
Damien Miller95def091999-11-25 00:26:21 +1100763 }
Damien Miller34132e52000-01-14 15:45:46 +1100764#endif /* LIBWRAP */
Damien Miller95def091999-11-25 00:26:21 +1100765 /* Log the connection. */
766 verbose("Connection from %.500s port %d", remote_ip, remote_port);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000767
Damien Miller5428f641999-11-25 11:54:57 +1100768 /*
769 * We don\'t want to listen forever unless the other side
770 * successfully authenticates itself. So we set up an alarm which is
771 * cleared after successful authentication. A limit of zero
772 * indicates no limit. Note that we don\'t set the alarm in debugging
773 * mode; it is just annoying to have the server exit just when you
774 * are about to discover the bug.
775 */
Damien Miller95def091999-11-25 00:26:21 +1100776 signal(SIGALRM, grace_alarm_handler);
777 if (!debug_flag)
778 alarm(options.login_grace_time);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000779
Damien Miller95def091999-11-25 00:26:21 +1100780 if (client_version_string != NULL) {
781 /* we are exec'ed by sshd2, so skip exchange of protocol version */
782 strlcpy(buf, client_version_string, sizeof(buf));
783 } else {
784 /* Send our protocol version identification. */
785 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
786 PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION);
Damien Millerf052aaf2000-01-22 19:47:21 +1100787 if (atomicio(write, sock_out, buf, strlen(buf)) != strlen(buf)) {
788 log("Could not write ident string to %s.", remote_ip);
789 fatal_cleanup();
790 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000791
Damien Miller95def091999-11-25 00:26:21 +1100792 /* Read other side\'s version identification. */
793 for (i = 0; i < sizeof(buf) - 1; i++) {
Damien Millerf052aaf2000-01-22 19:47:21 +1100794 if (read(sock_in, &buf[i], 1) != 1) {
795 log("Did not receive ident string from %s.", remote_ip);
796 fatal_cleanup();
797 }
Damien Miller95def091999-11-25 00:26:21 +1100798 if (buf[i] == '\r') {
799 buf[i] = '\n';
800 buf[i + 1] = 0;
801 break;
802 }
803 if (buf[i] == '\n') {
804 /* buf[i] == '\n' */
805 buf[i + 1] = 0;
806 break;
807 }
808 }
809 buf[sizeof(buf) - 1] = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000810 }
Damien Miller95def091999-11-25 00:26:21 +1100811
Damien Miller5428f641999-11-25 11:54:57 +1100812 /*
813 * Check that the versions match. In future this might accept
814 * several versions and set appropriate flags to handle them.
815 */
Damien Miller95def091999-11-25 00:26:21 +1100816 if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor,
Damien Miller037a0dc1999-12-07 15:38:31 +1100817 remote_version) != 3) {
818 char *s = "Protocol mismatch.\n";
819
820 (void) atomicio(write, sock_out, s, strlen(s));
Damien Miller95def091999-11-25 00:26:21 +1100821 close(sock_in);
822 close(sock_out);
Damien Millerf052aaf2000-01-22 19:47:21 +1100823 log("Bad protocol version identification '%.100s' from %s",
824 buf, remote_ip);
825 fatal_cleanup();
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000826 }
Damien Miller95def091999-11-25 00:26:21 +1100827 debug("Client protocol version %d.%d; client software version %.100s",
828 remote_major, remote_minor, remote_version);
829 if (remote_major != PROTOCOL_MAJOR) {
Damien Miller037a0dc1999-12-07 15:38:31 +1100830 char *s = "Protocol major versions differ.\n";
831
832 (void) atomicio(write, sock_out, s, strlen(s));
Damien Miller95def091999-11-25 00:26:21 +1100833 close(sock_in);
834 close(sock_out);
Damien Millerf052aaf2000-01-22 19:47:21 +1100835 log("Protocol major versions differ for %s: %d vs. %d",
836 remote_ip, PROTOCOL_MAJOR, remote_major);
837 fatal_cleanup();
Damien Miller95def091999-11-25 00:26:21 +1100838 }
839 /* Check that the client has sufficiently high software version. */
840 if (remote_major == 1 && remote_minor < 3)
841 packet_disconnect("Your ssh version is too old and is no longer supported. Please install a newer version.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000842
Damien Miller95def091999-11-25 00:26:21 +1100843 if (remote_major == 1 && remote_minor == 3) {
Damien Miller396691a2000-01-20 22:44:08 +1100844 /* note that this disables agent-forwarding */
Damien Miller95def091999-11-25 00:26:21 +1100845 enable_compat13();
Damien Miller95def091999-11-25 00:26:21 +1100846 }
Damien Miller5428f641999-11-25 11:54:57 +1100847 /*
848 * Check that the connection comes from a privileged port. Rhosts-
849 * and Rhosts-RSA-Authentication only make sense from priviledged
850 * programs. Of course, if the intruder has root access on his local
851 * machine, he can connect from any port. So do not use these
852 * authentication methods from machines that you do not trust.
853 */
Damien Miller95def091999-11-25 00:26:21 +1100854 if (remote_port >= IPPORT_RESERVED ||
855 remote_port < IPPORT_RESERVED / 2) {
856 options.rhosts_authentication = 0;
857 options.rhosts_rsa_authentication = 0;
858 }
Damien Miller34132e52000-01-14 15:45:46 +1100859#ifdef KRB4
860 if (!packet_connection_is_ipv4() &&
861 options.kerberos_authentication) {
862 debug("Kerberos Authentication disabled, only available for IPv4.");
863 options.kerberos_authentication = 0;
864 }
865#endif /* KRB4 */
866
Damien Miller95def091999-11-25 00:26:21 +1100867 packet_set_nonblocking();
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000868
Damien Miller396691a2000-01-20 22:44:08 +1100869 /* perform the key exchange */
870 do_ssh_kex();
871
872 /* authenticate user and start session */
873 do_authentication();
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000874
875#ifdef KRB4
Damien Miller95def091999-11-25 00:26:21 +1100876 /* Cleanup user's ticket cache file. */
877 if (options.kerberos_ticket_cleanup)
878 (void) dest_tkt();
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000879#endif /* KRB4 */
880
Damien Miller95def091999-11-25 00:26:21 +1100881 /* Cleanup user's local Xauthority file. */
882 if (xauthfile)
883 unlink(xauthfile);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000884
Damien Miller95def091999-11-25 00:26:21 +1100885 /* The connection has been terminated. */
886 verbose("Closing connection to %.100s", remote_ip);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000887
Damien Millerbeb4ba51999-12-28 15:09:35 +1100888#ifdef USE_PAM
Damien Millere72b7af1999-12-30 15:08:44 +1100889 finish_pam();
Damien Millerbeb4ba51999-12-28 15:09:35 +1100890#endif /* USE_PAM */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000891
Damien Miller95def091999-11-25 00:26:21 +1100892 packet_close();
893 exit(0);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000894}
895
Damien Miller95def091999-11-25 00:26:21 +1100896/*
Damien Miller396691a2000-01-20 22:44:08 +1100897 * SSH1 key exchange
Damien Miller95def091999-11-25 00:26:21 +1100898 */
Damien Miller2ccf6611999-11-15 15:25:10 +1100899void
Damien Miller396691a2000-01-20 22:44:08 +1100900do_ssh_kex()
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000901{
Damien Miller95def091999-11-25 00:26:21 +1100902 int i, len;
Damien Miller396691a2000-01-20 22:44:08 +1100903 int plen, slen;
Damien Miller95def091999-11-25 00:26:21 +1100904 BIGNUM *session_key_int;
905 unsigned char session_key[SSH_SESSION_KEY_LENGTH];
Damien Miller396691a2000-01-20 22:44:08 +1100906 unsigned char cookie[8];
Damien Miller95def091999-11-25 00:26:21 +1100907 unsigned int cipher_type, auth_mask, protocol_flags;
Damien Miller95def091999-11-25 00:26:21 +1100908 u_int32_t rand = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000909
Damien Miller5428f641999-11-25 11:54:57 +1100910 /*
911 * Generate check bytes that the client must send back in the user
912 * packet in order for it to be accepted; this is used to defy ip
913 * spoofing attacks. Note that this only works against somebody
914 * doing IP spoofing from a remote machine; any machine on the local
915 * network can still see outgoing packets and catch the random
916 * cookie. This only affects rhosts authentication, and this is one
917 * of the reasons why it is inherently insecure.
918 */
Damien Miller95def091999-11-25 00:26:21 +1100919 for (i = 0; i < 8; i++) {
920 if (i % 4 == 0)
921 rand = arc4random();
Damien Miller396691a2000-01-20 22:44:08 +1100922 cookie[i] = rand & 0xff;
Damien Miller95def091999-11-25 00:26:21 +1100923 rand >>= 8;
924 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000925
Damien Miller5428f641999-11-25 11:54:57 +1100926 /*
927 * Send our public key. We include in the packet 64 bits of random
928 * data that must be matched in the reply in order to prevent IP
929 * spoofing.
930 */
Damien Miller95def091999-11-25 00:26:21 +1100931 packet_start(SSH_SMSG_PUBLIC_KEY);
932 for (i = 0; i < 8; i++)
Damien Miller396691a2000-01-20 22:44:08 +1100933 packet_put_char(cookie[i]);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000934
Damien Miller95def091999-11-25 00:26:21 +1100935 /* Store our public server RSA key. */
936 packet_put_int(BN_num_bits(public_key->n));
937 packet_put_bignum(public_key->e);
938 packet_put_bignum(public_key->n);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000939
Damien Miller95def091999-11-25 00:26:21 +1100940 /* Store our public host RSA key. */
941 packet_put_int(BN_num_bits(sensitive_data.host_key->n));
942 packet_put_bignum(sensitive_data.host_key->e);
943 packet_put_bignum(sensitive_data.host_key->n);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000944
Damien Miller95def091999-11-25 00:26:21 +1100945 /* Put protocol flags. */
946 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000947
Damien Miller95def091999-11-25 00:26:21 +1100948 /* Declare which ciphers we support. */
949 packet_put_int(cipher_mask());
950
951 /* Declare supported authentication types. */
952 auth_mask = 0;
953 if (options.rhosts_authentication)
954 auth_mask |= 1 << SSH_AUTH_RHOSTS;
955 if (options.rhosts_rsa_authentication)
956 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
957 if (options.rsa_authentication)
958 auth_mask |= 1 << SSH_AUTH_RSA;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000959#ifdef KRB4
Damien Miller95def091999-11-25 00:26:21 +1100960 if (options.kerberos_authentication)
961 auth_mask |= 1 << SSH_AUTH_KERBEROS;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000962#endif
963#ifdef AFS
Damien Miller95def091999-11-25 00:26:21 +1100964 if (options.kerberos_tgt_passing)
965 auth_mask |= 1 << SSH_PASS_KERBEROS_TGT;
966 if (options.afs_token_passing)
967 auth_mask |= 1 << SSH_PASS_AFS_TOKEN;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000968#endif
Damien Miller95def091999-11-25 00:26:21 +1100969#ifdef SKEY
970 if (options.skey_authentication == 1)
971 auth_mask |= 1 << SSH_AUTH_TIS;
972#endif
973 if (options.password_authentication)
974 auth_mask |= 1 << SSH_AUTH_PASSWORD;
975 packet_put_int(auth_mask);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000976
Damien Miller95def091999-11-25 00:26:21 +1100977 /* Send the packet and wait for it to be sent. */
978 packet_send();
979 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000980
Damien Miller95def091999-11-25 00:26:21 +1100981 debug("Sent %d bit public key and %d bit host key.",
982 BN_num_bits(public_key->n), BN_num_bits(sensitive_data.host_key->n));
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000983
Damien Miller95def091999-11-25 00:26:21 +1100984 /* Read clients reply (cipher type and session key). */
985 packet_read_expect(&plen, SSH_CMSG_SESSION_KEY);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000986
Damien Miller50945fa1999-12-09 10:31:37 +1100987 /* Get cipher type and check whether we accept this. */
Damien Miller95def091999-11-25 00:26:21 +1100988 cipher_type = packet_get_char();
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000989
Damien Miller50945fa1999-12-09 10:31:37 +1100990 if (!(cipher_mask() & (1 << cipher_type)))
991 packet_disconnect("Warning: client selects unsupported cipher.");
992
Damien Miller95def091999-11-25 00:26:21 +1100993 /* Get check bytes from the packet. These must match those we
994 sent earlier with the public key packet. */
995 for (i = 0; i < 8; i++)
Damien Miller396691a2000-01-20 22:44:08 +1100996 if (cookie[i] != packet_get_char())
Damien Miller95def091999-11-25 00:26:21 +1100997 packet_disconnect("IP Spoofing check bytes do not match.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000998
Damien Miller95def091999-11-25 00:26:21 +1100999 debug("Encryption type: %.200s", cipher_name(cipher_type));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001000
Damien Miller95def091999-11-25 00:26:21 +11001001 /* Get the encrypted integer. */
1002 session_key_int = BN_new();
1003 packet_get_bignum(session_key_int, &slen);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001004
Damien Miller95def091999-11-25 00:26:21 +11001005 protocol_flags = packet_get_int();
1006 packet_set_protocol_flags(protocol_flags);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001007
Damien Miller95def091999-11-25 00:26:21 +11001008 packet_integrity_check(plen, 1 + 8 + slen + 4, SSH_CMSG_SESSION_KEY);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001009
Damien Miller5428f641999-11-25 11:54:57 +11001010 /*
1011 * Decrypt it using our private server key and private host key (key
1012 * with larger modulus first).
1013 */
Damien Miller95def091999-11-25 00:26:21 +11001014 if (BN_cmp(sensitive_data.private_key->n, sensitive_data.host_key->n) > 0) {
1015 /* Private key has bigger modulus. */
1016 if (BN_num_bits(sensitive_data.private_key->n) <
1017 BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) {
1018 fatal("do_connection: %s: private_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
1019 get_remote_ipaddr(),
1020 BN_num_bits(sensitive_data.private_key->n),
1021 BN_num_bits(sensitive_data.host_key->n),
1022 SSH_KEY_BITS_RESERVED);
1023 }
1024 rsa_private_decrypt(session_key_int, session_key_int,
1025 sensitive_data.private_key);
1026 rsa_private_decrypt(session_key_int, session_key_int,
1027 sensitive_data.host_key);
1028 } else {
1029 /* Host key has bigger modulus (or they are equal). */
1030 if (BN_num_bits(sensitive_data.host_key->n) <
1031 BN_num_bits(sensitive_data.private_key->n) + SSH_KEY_BITS_RESERVED) {
1032 fatal("do_connection: %s: host_key %d < private_key %d + SSH_KEY_BITS_RESERVED %d",
1033 get_remote_ipaddr(),
1034 BN_num_bits(sensitive_data.host_key->n),
1035 BN_num_bits(sensitive_data.private_key->n),
1036 SSH_KEY_BITS_RESERVED);
1037 }
1038 rsa_private_decrypt(session_key_int, session_key_int,
1039 sensitive_data.host_key);
1040 rsa_private_decrypt(session_key_int, session_key_int,
1041 sensitive_data.private_key);
1042 }
Damien Miller356a0b01999-11-08 15:30:59 +11001043
Damien Miller396691a2000-01-20 22:44:08 +11001044 compute_session_id(session_id, cookie,
Damien Miller95def091999-11-25 00:26:21 +11001045 sensitive_data.host_key->n,
1046 sensitive_data.private_key->n);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001047
Damien Miller396691a2000-01-20 22:44:08 +11001048 /* Destroy the private and public keys. They will no longer be needed. */
1049 RSA_free(public_key);
1050 RSA_free(sensitive_data.private_key);
1051 RSA_free(sensitive_data.host_key);
1052
Damien Miller5428f641999-11-25 11:54:57 +11001053 /*
1054 * Extract session key from the decrypted integer. The key is in the
1055 * least significant 256 bits of the integer; the first byte of the
1056 * key is in the highest bits.
1057 */
Damien Miller95def091999-11-25 00:26:21 +11001058 BN_mask_bits(session_key_int, sizeof(session_key) * 8);
1059 len = BN_num_bytes(session_key_int);
1060 if (len < 0 || len > sizeof(session_key))
1061 fatal("do_connection: bad len from %s: session_key_int %d > sizeof(session_key) %d",
1062 get_remote_ipaddr(),
1063 len, sizeof(session_key));
1064 memset(session_key, 0, sizeof(session_key));
1065 BN_bn2bin(session_key_int, session_key + sizeof(session_key) - len);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001066
Damien Miller396691a2000-01-20 22:44:08 +11001067 /* Destroy the decrypted integer. It is no longer needed. */
1068 BN_clear_free(session_key_int);
1069
Damien Miller95def091999-11-25 00:26:21 +11001070 /* Xor the first 16 bytes of the session key with the session id. */
1071 for (i = 0; i < 16; i++)
1072 session_key[i] ^= session_id[i];
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001073
Damien Miller95def091999-11-25 00:26:21 +11001074 /* Set the session key. From this on all communications will be encrypted. */
1075 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001076
Damien Miller95def091999-11-25 00:26:21 +11001077 /* Destroy our copy of the session key. It is no longer needed. */
1078 memset(session_key, 0, sizeof(session_key));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001079
Damien Miller95def091999-11-25 00:26:21 +11001080 debug("Received session key; encryption turned on.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001081
Damien Miller95def091999-11-25 00:26:21 +11001082 /* Send an acknowledgement packet. Note that this packet is sent encrypted. */
1083 packet_start(SSH_SMSG_SUCCESS);
1084 packet_send();
1085 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001086}
1087
Damien Miller396691a2000-01-20 22:44:08 +11001088
Damien Miller95def091999-11-25 00:26:21 +11001089/*
1090 * Check if the user is allowed to log in via ssh. If user is listed in
1091 * DenyUsers or user's primary group is listed in DenyGroups, false will
1092 * be returned. If AllowUsers isn't empty and user isn't listed there, or
1093 * if AllowGroups isn't empty and user isn't listed there, false will be
1094 * returned. Otherwise true is returned.
1095 * XXX This function should also check if user has a valid shell
1096 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001097static int
Damien Miller95def091999-11-25 00:26:21 +11001098allowed_user(struct passwd * pw)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001099{
Damien Miller95def091999-11-25 00:26:21 +11001100 struct group *grp;
1101 int i;
Damien Miller1fa154b2000-01-23 10:32:03 +11001102#ifdef WITH_AIXAUTHENTICATE
1103 char *loginmsg;
1104#endif /* WITH_AIXAUTHENTICATE */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001105
Damien Miller95def091999-11-25 00:26:21 +11001106 /* Shouldn't be called if pw is NULL, but better safe than sorry... */
1107 if (!pw)
1108 return 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001109
Damien Miller95def091999-11-25 00:26:21 +11001110 /* XXX Should check for valid login shell */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001111
Damien Miller95def091999-11-25 00:26:21 +11001112 /* Return false if user is listed in DenyUsers */
1113 if (options.num_deny_users > 0) {
1114 if (!pw->pw_name)
1115 return 0;
1116 for (i = 0; i < options.num_deny_users; i++)
1117 if (match_pattern(pw->pw_name, options.deny_users[i]))
1118 return 0;
1119 }
Damien Miller5428f641999-11-25 11:54:57 +11001120 /* Return false if AllowUsers isn't empty and user isn't listed there */
Damien Miller95def091999-11-25 00:26:21 +11001121 if (options.num_allow_users > 0) {
1122 if (!pw->pw_name)
1123 return 0;
1124 for (i = 0; i < options.num_allow_users; i++)
1125 if (match_pattern(pw->pw_name, options.allow_users[i]))
1126 break;
1127 /* i < options.num_allow_users iff we break for loop */
1128 if (i >= options.num_allow_users)
1129 return 0;
1130 }
1131 /* Get the primary group name if we need it. Return false if it fails */
1132 if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
1133 grp = getgrgid(pw->pw_gid);
1134 if (!grp)
1135 return 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001136
Damien Miller95def091999-11-25 00:26:21 +11001137 /* Return false if user's group is listed in DenyGroups */
1138 if (options.num_deny_groups > 0) {
1139 if (!grp->gr_name)
1140 return 0;
1141 for (i = 0; i < options.num_deny_groups; i++)
1142 if (match_pattern(grp->gr_name, options.deny_groups[i]))
1143 return 0;
1144 }
Damien Miller5428f641999-11-25 11:54:57 +11001145 /*
1146 * Return false if AllowGroups isn't empty and user's group
1147 * isn't listed there
1148 */
Damien Miller95def091999-11-25 00:26:21 +11001149 if (options.num_allow_groups > 0) {
1150 if (!grp->gr_name)
1151 return 0;
1152 for (i = 0; i < options.num_allow_groups; i++)
1153 if (match_pattern(grp->gr_name, options.allow_groups[i]))
1154 break;
1155 /* i < options.num_allow_groups iff we break for
1156 loop */
1157 if (i >= options.num_allow_groups)
1158 return 0;
1159 }
1160 }
Damien Miller1fa154b2000-01-23 10:32:03 +11001161
1162#ifdef WITH_AIXAUTHENTICATE
1163 if (loginrestrictions(pw->pw_name,S_LOGIN,NULL,&loginmsg) != 0)
1164 return 0;
1165#endif /* WITH_AIXAUTHENTICATE */
1166
Damien Miller95def091999-11-25 00:26:21 +11001167 /* We found no reason not to let this user try to log on... */
1168 return 1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001169}
1170
Damien Miller95def091999-11-25 00:26:21 +11001171/*
1172 * Performs authentication of an incoming connection. Session key has already
Damien Miller396691a2000-01-20 22:44:08 +11001173 * been exchanged and encryption is enabled.
Damien Miller95def091999-11-25 00:26:21 +11001174 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001175void
Damien Miller396691a2000-01-20 22:44:08 +11001176do_authentication()
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001177{
Damien Miller95def091999-11-25 00:26:21 +11001178 struct passwd *pw, pwcopy;
Damien Miller396691a2000-01-20 22:44:08 +11001179 int plen, ulen;
1180 char *user;
1181
1182 /* Get the name of the user that we wish to log in as. */
1183 packet_read_expect(&plen, SSH_CMSG_USER);
1184
1185 /* Get the user name. */
1186 user = packet_get_string(&ulen);
1187 packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER);
1188
1189 setproctitle("%s", user);
Damien Miller2ccf6611999-11-15 15:25:10 +11001190
Damien Miller1fa154b2000-01-23 10:32:03 +11001191#ifdef WITH_AIXAUTHENTICATE
1192 char *loginmsg;
1193#endif /* WITH_AIXAUTHENTICATE */
1194
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001195#ifdef AFS
Damien Miller95def091999-11-25 00:26:21 +11001196 /* If machine has AFS, set process authentication group. */
1197 if (k_hasafs()) {
1198 k_setpag();
1199 k_unlog();
1200 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001201#endif /* AFS */
Damien Miller95def091999-11-25 00:26:21 +11001202
1203 /* Verify that the user is a valid user. */
1204 pw = getpwnam(user);
1205 if (!pw || !allowed_user(pw))
1206 do_fake_authloop(user);
1207
1208 /* Take a copy of the returned structure. */
1209 memset(&pwcopy, 0, sizeof(pwcopy));
1210 pwcopy.pw_name = xstrdup(pw->pw_name);
1211 pwcopy.pw_passwd = xstrdup(pw->pw_passwd);
1212 pwcopy.pw_uid = pw->pw_uid;
1213 pwcopy.pw_gid = pw->pw_gid;
1214 pwcopy.pw_dir = xstrdup(pw->pw_dir);
1215 pwcopy.pw_shell = xstrdup(pw->pw_shell);
1216 pw = &pwcopy;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001217
Damien Millerbeb4ba51999-12-28 15:09:35 +11001218#ifdef USE_PAM
Damien Millere72b7af1999-12-30 15:08:44 +11001219 start_pam(pw);
Damien Miller06230761999-10-28 14:03:14 +10001220#endif
Damien Miller3d112ef1999-10-28 13:20:30 +10001221
Damien Miller5428f641999-11-25 11:54:57 +11001222 /*
1223 * If we are not running as root, the user must have the same uid as
1224 * the server.
1225 */
Damien Miller95def091999-11-25 00:26:21 +11001226 if (getuid() != 0 && pw->pw_uid != getuid())
1227 packet_disconnect("Cannot change user when server not running as root.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001228
Damien Miller95def091999-11-25 00:26:21 +11001229 debug("Attempting authentication for %.100s.", user);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001230
Damien Miller95def091999-11-25 00:26:21 +11001231 /* If the user has no password, accept authentication immediately. */
1232 if (options.password_authentication &&
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001233#ifdef KRB4
Damien Miller95def091999-11-25 00:26:21 +11001234 (!options.kerberos_authentication || options.kerberos_or_local_passwd) &&
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001235#endif /* KRB4 */
Damien Millerbeb4ba51999-12-28 15:09:35 +11001236#ifdef USE_PAM
Damien Millere72b7af1999-12-30 15:08:44 +11001237 auth_pam_password(pw, "")) {
Damien Millerbeb4ba51999-12-28 15:09:35 +11001238#else /* USE_PAM */
Damien Miller95def091999-11-25 00:26:21 +11001239 auth_password(pw, "")) {
Damien Millerbeb4ba51999-12-28 15:09:35 +11001240#endif /* USE_PAM */
Damien Miller95def091999-11-25 00:26:21 +11001241 /* Authentication with empty password succeeded. */
1242 log("Login for user %s from %.100s, accepted without authentication.",
1243 pw->pw_name, get_remote_ipaddr());
1244 } else {
1245 /* Loop until the user has been authenticated or the
1246 connection is closed, do_authloop() returns only if
1247 authentication is successfull */
1248 do_authloop(pw);
1249 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001250
Damien Miller95def091999-11-25 00:26:21 +11001251 /* Check if the user is logging in as root and root logins are disallowed. */
1252 if (pw->pw_uid == 0 && !options.permit_root_login) {
1253 if (forced_command)
1254 log("Root login accepted for forced command.");
1255 else
1256 packet_disconnect("ROOT LOGIN REFUSED FROM %.200s",
1257 get_canonical_hostname());
1258 }
1259 /* The user has been authenticated and accepted. */
Damien Miller1fa154b2000-01-23 10:32:03 +11001260#ifdef WITH_AIXAUTHENTICATE
1261 loginsuccess(user,get_canonical_hostname(),"ssh",&loginmsg);
1262#endif /* WITH_AIXAUTHENTICATE */
Damien Miller95def091999-11-25 00:26:21 +11001263 packet_start(SSH_SMSG_SUCCESS);
1264 packet_send();
1265 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001266
Damien Miller95def091999-11-25 00:26:21 +11001267 /* Perform session preparation. */
1268 do_authenticated(pw);
Damien Miller2ccf6611999-11-15 15:25:10 +11001269}
1270
Damien Miller95def091999-11-25 00:26:21 +11001271#define AUTH_FAIL_MAX 6
1272#define AUTH_FAIL_LOG (AUTH_FAIL_MAX/2)
1273#define AUTH_FAIL_MSG "Too many authentication failures for %.100s"
Damien Miller2ccf6611999-11-15 15:25:10 +11001274
Damien Miller95def091999-11-25 00:26:21 +11001275/*
1276 * read packets and try to authenticate local user *pw.
1277 * return if authentication is successfull
1278 */
Damien Miller2ccf6611999-11-15 15:25:10 +11001279void
Damien Miller95def091999-11-25 00:26:21 +11001280do_authloop(struct passwd * pw)
Damien Miller2ccf6611999-11-15 15:25:10 +11001281{
Damien Miller95def091999-11-25 00:26:21 +11001282 int attempt = 0;
1283 unsigned int bits;
1284 BIGNUM *client_host_key_e, *client_host_key_n;
1285 BIGNUM *n;
1286 char *client_user = NULL, *password = NULL;
1287 char user[1024];
1288 int plen, dlen, nlen, ulen, elen;
1289 int type = 0;
1290 void (*authlog) (const char *fmt,...) = verbose;
Damien Miller2ccf6611999-11-15 15:25:10 +11001291
Damien Miller95def091999-11-25 00:26:21 +11001292 /* Indicate that authentication is needed. */
1293 packet_start(SSH_SMSG_FAILURE);
1294 packet_send();
1295 packet_write_wait();
Damien Miller2ccf6611999-11-15 15:25:10 +11001296
Damien Miller95def091999-11-25 00:26:21 +11001297 for (attempt = 1;; attempt++) {
1298 int authenticated = 0;
1299 strlcpy(user, "", sizeof user);
Damien Miller2ccf6611999-11-15 15:25:10 +11001300
Damien Miller95def091999-11-25 00:26:21 +11001301 /* Get a packet from the client. */
1302 type = packet_read(&plen);
1303
1304 /* Process the packet. */
1305 switch (type) {
Damien Miller2ccf6611999-11-15 15:25:10 +11001306#ifdef AFS
Damien Miller95def091999-11-25 00:26:21 +11001307 case SSH_CMSG_HAVE_KERBEROS_TGT:
1308 if (!options.kerberos_tgt_passing) {
1309 /* packet_get_all(); */
1310 verbose("Kerberos tgt passing disabled.");
1311 break;
1312 } else {
1313 /* Accept Kerberos tgt. */
1314 char *tgt = packet_get_string(&dlen);
1315 packet_integrity_check(plen, 4 + dlen, type);
1316 if (!auth_kerberos_tgt(pw, tgt))
1317 verbose("Kerberos tgt REFUSED for %s", pw->pw_name);
1318 xfree(tgt);
1319 }
1320 continue;
1321
1322 case SSH_CMSG_HAVE_AFS_TOKEN:
1323 if (!options.afs_token_passing || !k_hasafs()) {
1324 /* packet_get_all(); */
1325 verbose("AFS token passing disabled.");
1326 break;
1327 } else {
1328 /* Accept AFS token. */
1329 char *token_string = packet_get_string(&dlen);
1330 packet_integrity_check(plen, 4 + dlen, type);
1331 if (!auth_afs_token(pw, token_string))
1332 verbose("AFS token REFUSED for %s", pw->pw_name);
1333 xfree(token_string);
1334 }
1335 continue;
Damien Miller2ccf6611999-11-15 15:25:10 +11001336#endif /* AFS */
Damien Miller2ccf6611999-11-15 15:25:10 +11001337#ifdef KRB4
Damien Miller95def091999-11-25 00:26:21 +11001338 case SSH_CMSG_AUTH_KERBEROS:
1339 if (!options.kerberos_authentication) {
1340 /* packet_get_all(); */
1341 verbose("Kerberos authentication disabled.");
1342 break;
1343 } else {
1344 /* Try Kerberos v4 authentication. */
1345 KTEXT_ST auth;
1346 char *tkt_user = NULL;
1347 char *kdata = packet_get_string((unsigned int *) &auth.length);
1348 packet_integrity_check(plen, 4 + auth.length, type);
Damien Miller2ccf6611999-11-15 15:25:10 +11001349
Damien Miller95def091999-11-25 00:26:21 +11001350 if (auth.length < MAX_KTXT_LEN)
1351 memcpy(auth.dat, kdata, auth.length);
1352 xfree(kdata);
1353
1354 authenticated = auth_krb4(pw->pw_name, &auth, &tkt_user);
1355
1356 if (authenticated) {
1357 snprintf(user, sizeof user, " tktuser %s", tkt_user);
1358 xfree(tkt_user);
1359 }
1360 }
1361 break;
Damien Miller2ccf6611999-11-15 15:25:10 +11001362#endif /* KRB4 */
Damien Miller2ccf6611999-11-15 15:25:10 +11001363
Damien Miller95def091999-11-25 00:26:21 +11001364 case SSH_CMSG_AUTH_RHOSTS:
1365 if (!options.rhosts_authentication) {
1366 verbose("Rhosts authentication disabled.");
1367 break;
1368 }
Damien Miller5428f641999-11-25 11:54:57 +11001369 /*
1370 * Get client user name. Note that we just have to
1371 * trust the client; this is one reason why rhosts
1372 * authentication is insecure. (Another is
1373 * IP-spoofing on a local network.)
1374 */
Damien Miller95def091999-11-25 00:26:21 +11001375 client_user = packet_get_string(&ulen);
1376 packet_integrity_check(plen, 4 + ulen, type);
1377
1378 /* Try to authenticate using /etc/hosts.equiv and
1379 .rhosts. */
1380 authenticated = auth_rhosts(pw, client_user);
1381
1382 snprintf(user, sizeof user, " ruser %s", client_user);
Damien Miller95def091999-11-25 00:26:21 +11001383 break;
Damien Miller7e8e8201999-11-16 13:37:16 +11001384
Damien Miller95def091999-11-25 00:26:21 +11001385 case SSH_CMSG_AUTH_RHOSTS_RSA:
1386 if (!options.rhosts_rsa_authentication) {
1387 verbose("Rhosts with RSA authentication disabled.");
1388 break;
1389 }
Damien Miller5428f641999-11-25 11:54:57 +11001390 /*
1391 * Get client user name. Note that we just have to
1392 * trust the client; root on the client machine can
1393 * claim to be any user.
1394 */
Damien Miller95def091999-11-25 00:26:21 +11001395 client_user = packet_get_string(&ulen);
1396
1397 /* Get the client host key. */
1398 client_host_key_e = BN_new();
1399 client_host_key_n = BN_new();
1400 bits = packet_get_int();
1401 packet_get_bignum(client_host_key_e, &elen);
1402 packet_get_bignum(client_host_key_n, &nlen);
1403
1404 if (bits != BN_num_bits(client_host_key_n))
1405 error("Warning: keysize mismatch for client_host_key: "
1406 "actual %d, announced %d", BN_num_bits(client_host_key_n), bits);
1407 packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type);
1408
1409 authenticated = auth_rhosts_rsa(pw, client_user,
1410 client_host_key_e, client_host_key_n);
1411 BN_clear_free(client_host_key_e);
1412 BN_clear_free(client_host_key_n);
1413
1414 snprintf(user, sizeof user, " ruser %s", client_user);
Damien Miller95def091999-11-25 00:26:21 +11001415 break;
Damien Miller81428f91999-11-18 09:28:11 +11001416
Damien Miller95def091999-11-25 00:26:21 +11001417 case SSH_CMSG_AUTH_RSA:
1418 if (!options.rsa_authentication) {
1419 verbose("RSA authentication disabled.");
1420 break;
1421 }
1422 /* RSA authentication requested. */
1423 n = BN_new();
1424 packet_get_bignum(n, &nlen);
1425 packet_integrity_check(plen, nlen, type);
1426 authenticated = auth_rsa(pw, n);
1427 BN_clear_free(n);
1428 break;
1429
1430 case SSH_CMSG_AUTH_PASSWORD:
1431 if (!options.password_authentication) {
1432 verbose("Password authentication disabled.");
1433 break;
1434 }
Damien Miller5428f641999-11-25 11:54:57 +11001435 /*
1436 * Read user password. It is in plain text, but was
1437 * transmitted over the encrypted channel so it is
1438 * not visible to an outside observer.
1439 */
Damien Miller95def091999-11-25 00:26:21 +11001440 password = packet_get_string(&dlen);
1441 packet_integrity_check(plen, 4 + dlen, type);
1442
Damien Millerbeb4ba51999-12-28 15:09:35 +11001443#ifdef USE_PAM
Damien Miller95def091999-11-25 00:26:21 +11001444 /* Do PAM auth with password */
Damien Millere72b7af1999-12-30 15:08:44 +11001445 authenticated = auth_pam_password(pw, password);
Damien Millerbeb4ba51999-12-28 15:09:35 +11001446#else /* USE_PAM */
Damien Miller95def091999-11-25 00:26:21 +11001447 /* Try authentication with the password. */
1448 authenticated = auth_password(pw, password);
Damien Millerbeb4ba51999-12-28 15:09:35 +11001449#endif /* USE_PAM */
Damien Miller95def091999-11-25 00:26:21 +11001450 memset(password, 0, strlen(password));
1451 xfree(password);
1452 break;
Damien Miller2ccf6611999-11-15 15:25:10 +11001453
Damien Miller95def091999-11-25 00:26:21 +11001454#ifdef SKEY
1455 case SSH_CMSG_AUTH_TIS:
1456 debug("rcvd SSH_CMSG_AUTH_TIS");
1457 if (options.skey_authentication == 1) {
1458 char *skeyinfo = skey_keyinfo(pw->pw_name);
1459 if (skeyinfo == NULL) {
1460 debug("generating fake skeyinfo for %.100s.", pw->pw_name);
1461 skeyinfo = skey_fake_keyinfo(pw->pw_name);
1462 }
1463 if (skeyinfo != NULL) {
Damien Miller5428f641999-11-25 11:54:57 +11001464 /* we send our s/key- in tis-challenge messages */
Damien Miller95def091999-11-25 00:26:21 +11001465 debug("sending challenge '%s'", skeyinfo);
1466 packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
1467 packet_put_string(skeyinfo, strlen(skeyinfo));
1468 packet_send();
1469 packet_write_wait();
1470 continue;
1471 }
1472 }
1473 break;
1474 case SSH_CMSG_AUTH_TIS_RESPONSE:
1475 debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE");
1476 if (options.skey_authentication == 1) {
1477 char *response = packet_get_string(&dlen);
1478 debug("skey response == '%s'", response);
1479 packet_integrity_check(plen, 4 + dlen, type);
1480 authenticated = (skey_haskey(pw->pw_name) == 0 &&
1481 skey_passcheck(pw->pw_name, response) != -1);
1482 xfree(response);
1483 }
1484 break;
1485#else
1486 case SSH_CMSG_AUTH_TIS:
1487 /* TIS Authentication is unsupported */
1488 log("TIS authentication unsupported.");
1489 break;
1490#endif
1491
1492 default:
Damien Miller5428f641999-11-25 11:54:57 +11001493 /*
1494 * Any unknown messages will be ignored (and failure
1495 * returned) during authentication.
1496 */
Damien Miller95def091999-11-25 00:26:21 +11001497 log("Unknown message during authentication: type %d", type);
1498 break;
1499 }
1500
1501 /* Raise logging level */
1502 if (authenticated ||
1503 attempt == AUTH_FAIL_LOG ||
1504 type == SSH_CMSG_AUTH_PASSWORD)
1505 authlog = log;
1506
1507 authlog("%s %s for %.200s from %.200s port %d%s",
1508 authenticated ? "Accepted" : "Failed",
1509 get_authname(type),
1510 pw->pw_uid == 0 ? "ROOT" : pw->pw_name,
1511 get_remote_ipaddr(),
1512 get_remote_port(),
1513 user);
Damien Miller2ccf6611999-11-15 15:25:10 +11001514
Damien Millere72b7af1999-12-30 15:08:44 +11001515 if (authenticated) {
1516#ifdef USE_PAM
Damien Miller1fa154b2000-01-23 10:32:03 +11001517 if (!do_pam_account(pw->pw_name, client_user)) {
Damien Millere72b7af1999-12-30 15:08:44 +11001518 if (client_user != NULL)
1519 xfree(client_user);
1520
1521 do_fake_authloop(pw->pw_name);
1522 }
1523#endif /* USE_PAM */
Damien Miller95def091999-11-25 00:26:21 +11001524 return;
Damien Millere72b7af1999-12-30 15:08:44 +11001525 }
1526
1527 if (client_user != NULL)
1528 xfree(client_user);
Damien Miller95def091999-11-25 00:26:21 +11001529
1530 if (attempt > AUTH_FAIL_MAX)
1531 packet_disconnect(AUTH_FAIL_MSG, pw->pw_name);
1532
1533 /* Send a message indicating that the authentication attempt failed. */
1534 packet_start(SSH_SMSG_FAILURE);
1535 packet_send();
1536 packet_write_wait();
1537 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001538}
1539
Damien Miller95def091999-11-25 00:26:21 +11001540/*
1541 * The user does not exist or access is denied,
1542 * but fake indication that authentication is needed.
1543 */
Damien Miller2ccf6611999-11-15 15:25:10 +11001544void
1545do_fake_authloop(char *user)
Damien Miller3d112ef1999-10-28 13:20:30 +10001546{
Damien Miller95def091999-11-25 00:26:21 +11001547 int attempt = 0;
Damien Miller2ccf6611999-11-15 15:25:10 +11001548
Damien Miller95def091999-11-25 00:26:21 +11001549 log("Faking authloop for illegal user %.200s from %.200s port %d",
1550 user,
1551 get_remote_ipaddr(),
1552 get_remote_port());
Damien Miller3d112ef1999-10-28 13:20:30 +10001553
Damien Miller95def091999-11-25 00:26:21 +11001554 /* Indicate that authentication is needed. */
1555 packet_start(SSH_SMSG_FAILURE);
1556 packet_send();
1557 packet_write_wait();
1558
Damien Miller5428f641999-11-25 11:54:57 +11001559 /*
1560 * Keep reading packets, and always respond with a failure. This is
1561 * to avoid disclosing whether such a user really exists.
1562 */
Damien Miller95def091999-11-25 00:26:21 +11001563 for (attempt = 1;; attempt++) {
Damien Miller5428f641999-11-25 11:54:57 +11001564 /* Read a packet. This will not return if the client disconnects. */
Damien Miller95def091999-11-25 00:26:21 +11001565 int plen;
Damien Millere72b7af1999-12-30 15:08:44 +11001566#ifndef SKEY
1567 (void)packet_read(&plen);
1568#else /* SKEY */
Damien Miller95def091999-11-25 00:26:21 +11001569 int type = packet_read(&plen);
Damien Miller95def091999-11-25 00:26:21 +11001570 int dlen;
1571 char *password, *skeyinfo;
Damien Millera34a28b1999-12-14 10:47:15 +11001572 /* Try to send a fake s/key challenge. */
1573 if (options.skey_authentication == 1 &&
Damien Miller95def091999-11-25 00:26:21 +11001574 (skeyinfo = skey_fake_keyinfo(user)) != NULL) {
Damien Millera34a28b1999-12-14 10:47:15 +11001575 if (type == SSH_CMSG_AUTH_TIS) {
1576 packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
1577 packet_put_string(skeyinfo, strlen(skeyinfo));
1578 packet_send();
1579 packet_write_wait();
1580 continue;
1581 } else if (type == SSH_CMSG_AUTH_PASSWORD &&
1582 options.password_authentication &&
1583 (password = packet_get_string(&dlen)) != NULL &&
1584 dlen == 5 &&
1585 strncasecmp(password, "s/key", 5) == 0 ) {
1586 packet_send_debug(skeyinfo);
1587 }
Damien Miller95def091999-11-25 00:26:21 +11001588 }
Damien Miller2ccf6611999-11-15 15:25:10 +11001589#endif
Damien Miller95def091999-11-25 00:26:21 +11001590 if (attempt > AUTH_FAIL_MAX)
1591 packet_disconnect(AUTH_FAIL_MSG, user);
1592
Damien Miller5428f641999-11-25 11:54:57 +11001593 /*
1594 * Send failure. This should be indistinguishable from a
1595 * failed authentication.
1596 */
Damien Miller95def091999-11-25 00:26:21 +11001597 packet_start(SSH_SMSG_FAILURE);
1598 packet_send();
1599 packet_write_wait();
Damien Miller1fa154b2000-01-23 10:32:03 +11001600#ifdef WITH_AIXAUTHENTICATE
1601 if (strncmp(get_authname(type),"password",
1602 strlen(get_authname(type))) == 0)
1603 loginfailed(pw->pw_name,get_canonical_hostname(),"ssh");
1604#endif /* WITH_AIXAUTHENTICATE */
Damien Miller95def091999-11-25 00:26:21 +11001605 }
1606 /* NOTREACHED */
1607 abort();
Damien Miller3d112ef1999-10-28 13:20:30 +10001608}
1609
Damien Miller2ccf6611999-11-15 15:25:10 +11001610
Damien Miller95def091999-11-25 00:26:21 +11001611/*
1612 * Remove local Xauthority file.
1613 */
Damien Miller5ce662a1999-11-11 17:57:39 +11001614static void
1615xauthfile_cleanup_proc(void *ignore)
1616{
Damien Miller95def091999-11-25 00:26:21 +11001617 debug("xauthfile_cleanup_proc called");
Damien Miller5ce662a1999-11-11 17:57:39 +11001618
Damien Miller95def091999-11-25 00:26:21 +11001619 if (xauthfile != NULL) {
1620 unlink(xauthfile);
1621 xfree(xauthfile);
1622 xauthfile = NULL;
1623 }
Damien Miller5ce662a1999-11-11 17:57:39 +11001624}
1625
Damien Miller95def091999-11-25 00:26:21 +11001626/*
1627 * Prepares for an interactive session. This is called after the user has
1628 * been successfully authenticated. During this message exchange, pseudo
1629 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
1630 * are requested, etc.
1631 */
1632void
1633do_authenticated(struct passwd * pw)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001634{
Damien Miller95def091999-11-25 00:26:21 +11001635 int type;
1636 int compression_level = 0, enable_compression_after_reply = 0;
1637 int have_pty = 0, ptyfd = -1, ttyfd = -1, xauthfd = -1;
1638 int row, col, xpixel, ypixel, screen;
1639 char ttyname[64];
1640 char *command, *term = NULL, *display = NULL, *proto = NULL,
1641 *data = NULL;
1642 struct group *grp;
1643 gid_t tty_gid;
1644 mode_t tty_mode;
1645 int n_bytes;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001646
Damien Miller5428f641999-11-25 11:54:57 +11001647 /*
1648 * Cancel the alarm we set to limit the time taken for
1649 * authentication.
1650 */
Damien Miller95def091999-11-25 00:26:21 +11001651 alarm(0);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001652
Damien Miller5428f641999-11-25 11:54:57 +11001653 /*
1654 * Inform the channel mechanism that we are the server side and that
1655 * the client may request to connect to any port at all. (The user
1656 * could do it anyway, and we wouldn\'t know what is permitted except
1657 * by the client telling us, so we can equally well trust the client
1658 * not to request anything bogus.)
1659 */
Damien Miller95def091999-11-25 00:26:21 +11001660 channel_permit_all_opens();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001661
Damien Miller5428f641999-11-25 11:54:57 +11001662 /*
1663 * We stay in this loop until the client requests to execute a shell
1664 * or a command.
1665 */
Damien Miller95def091999-11-25 00:26:21 +11001666 while (1) {
1667 int plen, dlen;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001668
Damien Miller95def091999-11-25 00:26:21 +11001669 /* Get a packet from the client. */
1670 type = packet_read(&plen);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001671
Damien Miller95def091999-11-25 00:26:21 +11001672 /* Process the packet. */
1673 switch (type) {
1674 case SSH_CMSG_REQUEST_COMPRESSION:
1675 packet_integrity_check(plen, 4, type);
1676 compression_level = packet_get_int();
1677 if (compression_level < 1 || compression_level > 9) {
1678 packet_send_debug("Received illegal compression level %d.",
1679 compression_level);
1680 goto fail;
1681 }
1682 /* Enable compression after we have responded with SUCCESS. */
1683 enable_compression_after_reply = 1;
1684 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001685
Damien Miller95def091999-11-25 00:26:21 +11001686 case SSH_CMSG_REQUEST_PTY:
1687 if (no_pty_flag) {
1688 debug("Allocating a pty not permitted for this authentication.");
1689 goto fail;
1690 }
1691 if (have_pty)
1692 packet_disconnect("Protocol error: you already have a pty.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001693
Damien Miller95def091999-11-25 00:26:21 +11001694 debug("Allocating pty.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001695
Damien Miller95def091999-11-25 00:26:21 +11001696 /* Allocate a pty and open it. */
Damien Miller037a0dc1999-12-07 15:38:31 +11001697 if (!pty_allocate(&ptyfd, &ttyfd, ttyname,
1698 sizeof(ttyname))) {
Damien Miller95def091999-11-25 00:26:21 +11001699 error("Failed to allocate pty.");
1700 goto fail;
1701 }
1702 /* Determine the group to make the owner of the tty. */
1703 grp = getgrnam("tty");
1704 if (grp) {
1705 tty_gid = grp->gr_gid;
1706 tty_mode = S_IRUSR | S_IWUSR | S_IWGRP;
1707 } else {
1708 tty_gid = pw->pw_gid;
1709 tty_mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH;
1710 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001711
Damien Miller95def091999-11-25 00:26:21 +11001712 /* Change ownership of the tty. */
1713 if (chown(ttyname, pw->pw_uid, tty_gid) < 0)
1714 fatal("chown(%.100s, %d, %d) failed: %.100s",
1715 ttyname, pw->pw_uid, tty_gid, strerror(errno));
1716 if (chmod(ttyname, tty_mode) < 0)
1717 fatal("chmod(%.100s, 0%o) failed: %.100s",
1718 ttyname, tty_mode, strerror(errno));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001719
Damien Miller95def091999-11-25 00:26:21 +11001720 /* Get TERM from the packet. Note that the value may be of arbitrary length. */
1721 term = packet_get_string(&dlen);
1722 packet_integrity_check(dlen, strlen(term), type);
1723 /* packet_integrity_check(plen, 4 + dlen + 4*4 + n_bytes, type); */
1724 /* Remaining bytes */
1725 n_bytes = plen - (4 + dlen + 4 * 4);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001726
Damien Miller95def091999-11-25 00:26:21 +11001727 if (strcmp(term, "") == 0)
1728 term = NULL;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001729
Damien Miller95def091999-11-25 00:26:21 +11001730 /* Get window size from the packet. */
1731 row = packet_get_int();
1732 col = packet_get_int();
1733 xpixel = packet_get_int();
1734 ypixel = packet_get_int();
1735 pty_change_window_size(ptyfd, row, col, xpixel, ypixel);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001736
Damien Miller95def091999-11-25 00:26:21 +11001737 /* Get tty modes from the packet. */
1738 tty_parse_modes(ttyfd, &n_bytes);
1739 packet_integrity_check(plen, 4 + dlen + 4 * 4 + n_bytes, type);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001740
Damien Miller95def091999-11-25 00:26:21 +11001741 /* Indicate that we now have a pty. */
1742 have_pty = 1;
Damien Millerbf1c9b21999-12-09 10:16:54 +11001743
Damien Millerbeb4ba51999-12-28 15:09:35 +11001744#ifdef USE_PAM
Damien Millerbf1c9b21999-12-09 10:16:54 +11001745 /* do the pam_open_session since we have the pty */
Damien Millere72b7af1999-12-30 15:08:44 +11001746 do_pam_session(pw->pw_name, ttyname);
Damien Millerbeb4ba51999-12-28 15:09:35 +11001747#endif /* USE_PAM */
Damien Millerbf1c9b21999-12-09 10:16:54 +11001748
Damien Miller95def091999-11-25 00:26:21 +11001749 break;
1750
1751 case SSH_CMSG_X11_REQUEST_FORWARDING:
1752 if (!options.x11_forwarding) {
1753 packet_send_debug("X11 forwarding disabled in server configuration file.");
1754 goto fail;
1755 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001756#ifdef XAUTH_PATH
Damien Miller95def091999-11-25 00:26:21 +11001757 if (no_x11_forwarding_flag) {
1758 packet_send_debug("X11 forwarding not permitted for this authentication.");
1759 goto fail;
1760 }
1761 debug("Received request for X11 forwarding with auth spoofing.");
1762 if (display)
1763 packet_disconnect("Protocol error: X11 display already set.");
1764 {
1765 int proto_len, data_len;
1766 proto = packet_get_string(&proto_len);
1767 data = packet_get_string(&data_len);
1768 packet_integrity_check(plen, 4 + proto_len + 4 + data_len + 4, type);
1769 }
1770 if (packet_get_protocol_flags() & SSH_PROTOFLAG_SCREEN_NUMBER)
1771 screen = packet_get_int();
1772 else
1773 screen = 0;
Damien Millera34a28b1999-12-14 10:47:15 +11001774 display = x11_create_display_inet(screen, options.x11_display_offset);
Damien Miller95def091999-11-25 00:26:21 +11001775 if (!display)
1776 goto fail;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001777
Damien Miller95def091999-11-25 00:26:21 +11001778 /* Setup to always have a local .Xauthority. */
1779 xauthfile = xmalloc(MAXPATHLEN);
1780 snprintf(xauthfile, MAXPATHLEN, "/tmp/XauthXXXXXX");
1781
1782 if ((xauthfd = mkstemp(xauthfile)) != -1) {
1783 fchown(xauthfd, pw->pw_uid, pw->pw_gid);
1784 close(xauthfd);
1785 fatal_add_cleanup(xauthfile_cleanup_proc, NULL);
1786 } else {
1787 xfree(xauthfile);
1788 xauthfile = NULL;
1789 }
1790 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001791#else /* XAUTH_PATH */
Damien Miller95def091999-11-25 00:26:21 +11001792 packet_send_debug("No xauth program; cannot forward with spoofing.");
1793 goto fail;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001794#endif /* XAUTH_PATH */
1795
Damien Miller95def091999-11-25 00:26:21 +11001796 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
Damien Miller396691a2000-01-20 22:44:08 +11001797 if (no_agent_forwarding_flag || compat13) {
Damien Miller95def091999-11-25 00:26:21 +11001798 debug("Authentication agent forwarding not permitted for this authentication.");
1799 goto fail;
1800 }
1801 debug("Received authentication agent forwarding request.");
1802 auth_input_request_forwarding(pw);
1803 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001804
Damien Miller95def091999-11-25 00:26:21 +11001805 case SSH_CMSG_PORT_FORWARD_REQUEST:
1806 if (no_port_forwarding_flag) {
1807 debug("Port forwarding not permitted for this authentication.");
1808 goto fail;
1809 }
1810 debug("Received TCP/IP port forwarding request.");
1811 channel_input_port_forward_request(pw->pw_uid == 0);
1812 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001813
Damien Miller95def091999-11-25 00:26:21 +11001814 case SSH_CMSG_MAX_PACKET_SIZE:
1815 if (packet_set_maxsize(packet_get_int()) < 0)
1816 goto fail;
1817 break;
Damien Miller6162d121999-11-21 13:23:52 +11001818
Damien Miller95def091999-11-25 00:26:21 +11001819 case SSH_CMSG_EXEC_SHELL:
1820 /* Set interactive/non-interactive mode. */
1821 packet_set_interactive(have_pty || display != NULL,
1822 options.keepalives);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001823
Damien Millerac3a4b41999-12-29 10:25:40 +11001824#ifdef USE_PAM
1825 do_pam_setcred();
Damien Millere72b7af1999-12-30 15:08:44 +11001826#endif /* USE_PAM */
Damien Miller95def091999-11-25 00:26:21 +11001827 if (forced_command != NULL)
1828 goto do_forced_command;
1829 debug("Forking shell.");
1830 packet_integrity_check(plen, 0, type);
1831 if (have_pty)
1832 do_exec_pty(NULL, ptyfd, ttyfd, ttyname, pw, term, display, proto, data);
1833 else
1834 do_exec_no_pty(NULL, pw, display, proto, data);
1835 return;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001836
Damien Miller95def091999-11-25 00:26:21 +11001837 case SSH_CMSG_EXEC_CMD:
1838 /* Set interactive/non-interactive mode. */
1839 packet_set_interactive(have_pty || display != NULL,
1840 options.keepalives);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001841
Damien Millerac3a4b41999-12-29 10:25:40 +11001842#ifdef USE_PAM
1843 do_pam_setcred();
Damien Millere72b7af1999-12-30 15:08:44 +11001844#endif /* USE_PAM */
Damien Miller95def091999-11-25 00:26:21 +11001845 if (forced_command != NULL)
1846 goto do_forced_command;
1847 /* Get command from the packet. */
1848 {
1849 int dlen;
1850 command = packet_get_string(&dlen);
1851 debug("Executing command '%.500s'", command);
1852 packet_integrity_check(plen, 4 + dlen, type);
1853 }
1854 if (have_pty)
1855 do_exec_pty(command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data);
1856 else
1857 do_exec_no_pty(command, pw, display, proto, data);
1858 xfree(command);
1859 return;
1860
1861 default:
Damien Miller5428f641999-11-25 11:54:57 +11001862 /*
1863 * Any unknown messages in this phase are ignored,
1864 * and a failure message is returned.
1865 */
Damien Miller95def091999-11-25 00:26:21 +11001866 log("Unknown packet type received after authentication: %d", type);
1867 goto fail;
1868 }
1869
1870 /* The request was successfully processed. */
1871 packet_start(SSH_SMSG_SUCCESS);
1872 packet_send();
1873 packet_write_wait();
1874
1875 /* Enable compression now that we have replied if appropriate. */
1876 if (enable_compression_after_reply) {
1877 enable_compression_after_reply = 0;
1878 packet_start_compression(compression_level);
1879 }
1880 continue;
1881
1882fail:
1883 /* The request failed. */
1884 packet_start(SSH_SMSG_FAILURE);
1885 packet_send();
1886 packet_write_wait();
1887 continue;
1888
1889do_forced_command:
Damien Miller5428f641999-11-25 11:54:57 +11001890 /*
1891 * There is a forced command specified for this login.
1892 * Execute it.
1893 */
Damien Miller95def091999-11-25 00:26:21 +11001894 debug("Executing forced command: %.900s", forced_command);
1895 if (have_pty)
1896 do_exec_pty(forced_command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data);
1897 else
1898 do_exec_no_pty(forced_command, pw, display, proto, data);
1899 return;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001900 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001901}
1902
Damien Miller95def091999-11-25 00:26:21 +11001903/*
1904 * This is called to fork and execute a command when we have no tty. This
1905 * will call do_child from the child, and server_loop from the parent after
1906 * setting up file descriptors and such.
1907 */
1908void
1909do_exec_no_pty(const char *command, struct passwd * pw,
1910 const char *display, const char *auth_proto,
1911 const char *auth_data)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001912{
Damien Miller95def091999-11-25 00:26:21 +11001913 int pid;
1914
1915#ifdef USE_PIPES
1916 int pin[2], pout[2], perr[2];
1917 /* Allocate pipes for communicating with the program. */
1918 if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
1919 packet_disconnect("Could not create pipes: %.100s",
1920 strerror(errno));
1921#else /* USE_PIPES */
1922 int inout[2], err[2];
1923 /* Uses socket pairs to communicate with the program. */
1924 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
1925 socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
1926 packet_disconnect("Could not create socket pairs: %.100s",
1927 strerror(errno));
1928#endif /* USE_PIPES */
1929
1930 setproctitle("%s@notty", pw->pw_name);
1931
1932 /* Fork the child. */
1933 if ((pid = fork()) == 0) {
1934 /* Child. Reinitialize the log since the pid has changed. */
1935 log_init(av0, options.log_level, options.log_facility, log_stderr);
1936
Damien Miller5428f641999-11-25 11:54:57 +11001937 /*
1938 * Create a new session and process group since the 4.4BSD
1939 * setlogin() affects the entire process group.
1940 */
Damien Miller95def091999-11-25 00:26:21 +11001941 if (setsid() < 0)
1942 error("setsid failed: %.100s", strerror(errno));
1943
1944#ifdef USE_PIPES
Damien Miller5428f641999-11-25 11:54:57 +11001945 /*
1946 * Redirect stdin. We close the parent side of the socket
1947 * pair, and make the child side the standard input.
1948 */
Damien Miller95def091999-11-25 00:26:21 +11001949 close(pin[1]);
1950 if (dup2(pin[0], 0) < 0)
1951 perror("dup2 stdin");
1952 close(pin[0]);
1953
1954 /* Redirect stdout. */
1955 close(pout[0]);
1956 if (dup2(pout[1], 1) < 0)
1957 perror("dup2 stdout");
1958 close(pout[1]);
1959
1960 /* Redirect stderr. */
1961 close(perr[0]);
1962 if (dup2(perr[1], 2) < 0)
1963 perror("dup2 stderr");
1964 close(perr[1]);
1965#else /* USE_PIPES */
Damien Miller5428f641999-11-25 11:54:57 +11001966 /*
1967 * Redirect stdin, stdout, and stderr. Stdin and stdout will
1968 * use the same socket, as some programs (particularly rdist)
1969 * seem to depend on it.
1970 */
Damien Miller95def091999-11-25 00:26:21 +11001971 close(inout[1]);
1972 close(err[1]);
1973 if (dup2(inout[0], 0) < 0) /* stdin */
1974 perror("dup2 stdin");
1975 if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */
1976 perror("dup2 stdout");
1977 if (dup2(err[0], 2) < 0) /* stderr */
1978 perror("dup2 stderr");
1979#endif /* USE_PIPES */
1980
1981 /* Do processing for the child (exec command etc). */
1982 do_child(command, pw, NULL, display, auth_proto, auth_data, NULL);
1983 /* NOTREACHED */
1984 }
1985 if (pid < 0)
1986 packet_disconnect("fork failed: %.100s", strerror(errno));
1987#ifdef USE_PIPES
1988 /* We are the parent. Close the child sides of the pipes. */
1989 close(pin[0]);
1990 close(pout[1]);
1991 close(perr[1]);
1992
1993 /* Enter the interactive session. */
1994 server_loop(pid, pin[1], pout[0], perr[0]);
1995 /* server_loop has closed pin[1], pout[1], and perr[1]. */
1996#else /* USE_PIPES */
1997 /* We are the parent. Close the child sides of the socket pairs. */
1998 close(inout[0]);
1999 close(err[0]);
2000
Damien Miller5428f641999-11-25 11:54:57 +11002001 /*
2002 * Enter the interactive session. Note: server_loop must be able to
2003 * handle the case that fdin and fdout are the same.
2004 */
Damien Miller95def091999-11-25 00:26:21 +11002005 server_loop(pid, inout[1], inout[1], err[1]);
2006 /* server_loop has closed inout[1] and err[1]. */
2007#endif /* USE_PIPES */
2008}
2009
2010struct pty_cleanup_context {
2011 const char *ttyname;
2012 int pid;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002013};
2014
Damien Miller95def091999-11-25 00:26:21 +11002015/*
2016 * Function to perform cleanup if we get aborted abnormally (e.g., due to a
2017 * dropped connection).
2018 */
2019void
2020pty_cleanup_proc(void *context)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002021{
Damien Miller95def091999-11-25 00:26:21 +11002022 struct pty_cleanup_context *cu = context;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002023
Damien Miller95def091999-11-25 00:26:21 +11002024 debug("pty_cleanup_proc called");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002025
Damien Miller95def091999-11-25 00:26:21 +11002026 /* Record that the user has logged out. */
2027 record_logout(cu->pid, cu->ttyname);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002028
Damien Miller95def091999-11-25 00:26:21 +11002029 /* Release the pseudo-tty. */
2030 pty_release(cu->ttyname);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002031}
2032
Damien Miller95def091999-11-25 00:26:21 +11002033/*
2034 * This is called to fork and execute a command when we have a tty. This
2035 * will call do_child from the child, and server_loop from the parent after
2036 * setting up file descriptors, controlling tty, updating wtmp, utmp,
2037 * lastlog, and other such operations.
2038 */
2039void
2040do_exec_pty(const char *command, int ptyfd, int ttyfd,
2041 const char *ttyname, struct passwd * pw, const char *term,
2042 const char *display, const char *auth_proto,
2043 const char *auth_data)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002044{
Damien Miller95def091999-11-25 00:26:21 +11002045 int pid, fdout;
2046 const char *hostname;
2047 time_t last_login_time;
2048 char buf[100], *time_string;
2049 FILE *f;
2050 char line[256];
2051 struct stat st;
2052 int quiet_login;
Damien Miller34132e52000-01-14 15:45:46 +11002053 struct sockaddr_storage from;
2054 socklen_t fromlen;
Damien Miller95def091999-11-25 00:26:21 +11002055 struct pty_cleanup_context cleanup_context;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002056
Damien Miller95def091999-11-25 00:26:21 +11002057 /* Get remote host name. */
2058 hostname = get_canonical_hostname();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002059
Damien Miller5428f641999-11-25 11:54:57 +11002060 /*
2061 * Get the time when the user last logged in. Buf will be set to
2062 * contain the hostname the last login was from.
2063 */
Damien Miller95def091999-11-25 00:26:21 +11002064 if (!options.use_login) {
2065 last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name,
2066 buf, sizeof(buf));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002067 }
Damien Miller95def091999-11-25 00:26:21 +11002068 setproctitle("%s@%s", pw->pw_name, strrchr(ttyname, '/') + 1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002069
Damien Miller95def091999-11-25 00:26:21 +11002070 /* Fork the child. */
2071 if ((pid = fork()) == 0) {
2072 pid = getpid();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002073
Damien Miller95def091999-11-25 00:26:21 +11002074 /* Child. Reinitialize the log because the pid has
2075 changed. */
2076 log_init(av0, options.log_level, options.log_facility, log_stderr);
2077
2078 /* Close the master side of the pseudo tty. */
2079 close(ptyfd);
2080
2081 /* Make the pseudo tty our controlling tty. */
2082 pty_make_controlling_tty(&ttyfd, ttyname);
2083
2084 /* Redirect stdin from the pseudo tty. */
2085 if (dup2(ttyfd, fileno(stdin)) < 0)
2086 error("dup2 stdin failed: %.100s", strerror(errno));
2087
2088 /* Redirect stdout to the pseudo tty. */
2089 if (dup2(ttyfd, fileno(stdout)) < 0)
2090 error("dup2 stdin failed: %.100s", strerror(errno));
2091
2092 /* Redirect stderr to the pseudo tty. */
2093 if (dup2(ttyfd, fileno(stderr)) < 0)
2094 error("dup2 stdin failed: %.100s", strerror(errno));
2095
2096 /* Close the extra descriptor for the pseudo tty. */
2097 close(ttyfd);
2098
Damien Miller5428f641999-11-25 11:54:57 +11002099 /*
2100 * Get IP address of client. This is needed because we want
2101 * to record where the user logged in from. If the
2102 * connection is not a socket, let the ip address be 0.0.0.0.
2103 */
Damien Miller95def091999-11-25 00:26:21 +11002104 memset(&from, 0, sizeof(from));
2105 if (packet_get_connection_in() == packet_get_connection_out()) {
2106 fromlen = sizeof(from);
2107 if (getpeername(packet_get_connection_in(),
2108 (struct sockaddr *) & from, &fromlen) < 0) {
2109 debug("getpeername: %.100s", strerror(errno));
2110 fatal_cleanup();
2111 }
2112 }
2113 /* Record that there was a login on that terminal. */
2114 record_login(pid, ttyname, pw->pw_name, pw->pw_uid, hostname,
Damien Miller34132e52000-01-14 15:45:46 +11002115 (struct sockaddr *)&from);
Damien Miller95def091999-11-25 00:26:21 +11002116
2117 /* Check if .hushlogin exists. */
2118 snprintf(line, sizeof line, "%.200s/.hushlogin", pw->pw_dir);
2119 quiet_login = stat(line, &st) >= 0;
Damien Miller356a0b01999-11-08 15:30:59 +11002120
Damien Millerbeb4ba51999-12-28 15:09:35 +11002121#ifdef USE_PAM
Damien Millere72b7af1999-12-30 15:08:44 +11002122 if (!quiet_login)
2123 print_pam_messages();
2124#endif /* USE_PAM */
Damien Miller95def091999-11-25 00:26:21 +11002125
Damien Miller5428f641999-11-25 11:54:57 +11002126 /*
2127 * If the user has logged in before, display the time of last
2128 * login. However, don't display anything extra if a command
2129 * has been specified (so that ssh can be used to execute
2130 * commands on a remote machine without users knowing they
2131 * are going to another machine). Login(1) will do this for
2132 * us as well, so check if login(1) is used
2133 */
Damien Miller95def091999-11-25 00:26:21 +11002134 if (command == NULL && last_login_time != 0 && !quiet_login &&
2135 !options.use_login) {
2136 /* Convert the date to a string. */
2137 time_string = ctime(&last_login_time);
2138 /* Remove the trailing newline. */
2139 if (strchr(time_string, '\n'))
2140 *strchr(time_string, '\n') = 0;
2141 /* Display the last login time. Host if displayed
2142 if known. */
2143 if (strcmp(buf, "") == 0)
2144 printf("Last login: %s\r\n", time_string);
2145 else
2146 printf("Last login: %s from %s\r\n", time_string, buf);
2147 }
Damien Miller5428f641999-11-25 11:54:57 +11002148 /*
2149 * Print /etc/motd unless a command was specified or printing
2150 * it was disabled in server options or login(1) will be
2151 * used. Note that some machines appear to print it in
2152 * /etc/profile or similar.
2153 */
Damien Miller95def091999-11-25 00:26:21 +11002154 if (command == NULL && options.print_motd && !quiet_login &&
2155 !options.use_login) {
2156 /* Print /etc/motd if it exists. */
2157 f = fopen("/etc/motd", "r");
2158 if (f) {
2159 while (fgets(line, sizeof(line), f))
2160 fputs(line, stdout);
2161 fclose(f);
2162 }
2163 }
2164 /* Do common processing for the child, such as execing the command. */
2165 do_child(command, pw, term, display, auth_proto, auth_data, ttyname);
2166 /* NOTREACHED */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002167 }
Damien Miller95def091999-11-25 00:26:21 +11002168 if (pid < 0)
2169 packet_disconnect("fork failed: %.100s", strerror(errno));
2170 /* Parent. Close the slave side of the pseudo tty. */
2171 close(ttyfd);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002172
Damien Miller5428f641999-11-25 11:54:57 +11002173 /*
2174 * Create another descriptor of the pty master side for use as the
2175 * standard input. We could use the original descriptor, but this
2176 * simplifies code in server_loop. The descriptor is bidirectional.
2177 */
Damien Miller95def091999-11-25 00:26:21 +11002178 fdout = dup(ptyfd);
2179 if (fdout < 0)
2180 packet_disconnect("dup failed: %.100s", strerror(errno));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002181
Damien Miller5428f641999-11-25 11:54:57 +11002182 /*
2183 * Add a cleanup function to clear the utmp entry and record logout
2184 * time in case we call fatal() (e.g., the connection gets closed).
2185 */
Damien Miller95def091999-11-25 00:26:21 +11002186 cleanup_context.pid = pid;
2187 cleanup_context.ttyname = ttyname;
2188 fatal_add_cleanup(pty_cleanup_proc, (void *) &cleanup_context);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002189
Damien Miller95def091999-11-25 00:26:21 +11002190 /* Enter interactive session. */
2191 server_loop(pid, ptyfd, fdout, -1);
2192 /* server_loop has not closed ptyfd and fdout. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002193
Damien Miller95def091999-11-25 00:26:21 +11002194 /* Cancel the cleanup function. */
2195 fatal_remove_cleanup(pty_cleanup_proc, (void *) &cleanup_context);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002196
Damien Miller95def091999-11-25 00:26:21 +11002197 /* Record that the user has logged out. */
2198 record_logout(pid, ttyname);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002199
Damien Miller95def091999-11-25 00:26:21 +11002200 /* Release the pseudo-tty. */
2201 pty_release(ttyname);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002202
Damien Miller5428f641999-11-25 11:54:57 +11002203 /*
2204 * Close the server side of the socket pairs. We must do this after
2205 * the pty cleanup, so that another process doesn't get this pty
2206 * while we're still cleaning up.
2207 */
Damien Miller95def091999-11-25 00:26:21 +11002208 close(ptyfd);
2209 close(fdout);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002210}
2211
Damien Miller95def091999-11-25 00:26:21 +11002212/*
2213 * Sets the value of the given variable in the environment. If the variable
2214 * already exists, its value is overriden.
2215 */
2216void
2217child_set_env(char ***envp, unsigned int *envsizep, const char *name,
2218 const char *value)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002219{
Damien Miller95def091999-11-25 00:26:21 +11002220 unsigned int i, namelen;
2221 char **env;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002222
Damien Miller5428f641999-11-25 11:54:57 +11002223 /*
2224 * Find the slot where the value should be stored. If the variable
2225 * already exists, we reuse the slot; otherwise we append a new slot
2226 * at the end of the array, expanding if necessary.
2227 */
Damien Miller95def091999-11-25 00:26:21 +11002228 env = *envp;
2229 namelen = strlen(name);
2230 for (i = 0; env[i]; i++)
2231 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
2232 break;
2233 if (env[i]) {
Damien Miller5428f641999-11-25 11:54:57 +11002234 /* Reuse the slot. */
Damien Miller95def091999-11-25 00:26:21 +11002235 xfree(env[i]);
2236 } else {
Damien Miller5428f641999-11-25 11:54:57 +11002237 /* New variable. Expand if necessary. */
Damien Miller95def091999-11-25 00:26:21 +11002238 if (i >= (*envsizep) - 1) {
2239 (*envsizep) += 50;
2240 env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *));
2241 }
2242 /* Need to set the NULL pointer at end of array beyond the new slot. */
2243 env[i + 1] = NULL;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002244 }
2245
Damien Miller95def091999-11-25 00:26:21 +11002246 /* Allocate space and format the variable in the appropriate slot. */
2247 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
2248 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002249}
2250
Damien Miller95def091999-11-25 00:26:21 +11002251/*
2252 * Reads environment variables from the given file and adds/overrides them
2253 * into the environment. If the file does not exist, this does nothing.
2254 * Otherwise, it must consist of empty lines, comments (line starts with '#')
2255 * and assignments of the form name=value. No other forms are allowed.
2256 */
2257void
2258read_environment_file(char ***env, unsigned int *envsize,
2259 const char *filename)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002260{
Damien Miller95def091999-11-25 00:26:21 +11002261 FILE *f;
2262 char buf[4096];
2263 char *cp, *value;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002264
Damien Miller95def091999-11-25 00:26:21 +11002265 f = fopen(filename, "r");
2266 if (!f)
2267 return;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002268
Damien Miller95def091999-11-25 00:26:21 +11002269 while (fgets(buf, sizeof(buf), f)) {
Damien Miller5428f641999-11-25 11:54:57 +11002270 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
2271 ;
Damien Miller95def091999-11-25 00:26:21 +11002272 if (!*cp || *cp == '#' || *cp == '\n')
2273 continue;
Damien Miller95def091999-11-25 00:26:21 +11002274 if (strchr(cp, '\n'))
2275 *strchr(cp, '\n') = '\0';
Damien Miller95def091999-11-25 00:26:21 +11002276 value = strchr(cp, '=');
2277 if (value == NULL) {
2278 fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf);
2279 continue;
2280 }
Damien Miller5428f641999-11-25 11:54:57 +11002281 /* Replace the equals sign by nul, and advance value to the value string. */
Damien Miller95def091999-11-25 00:26:21 +11002282 *value = '\0';
2283 value++;
Damien Miller95def091999-11-25 00:26:21 +11002284 child_set_env(env, envsize, cp, value);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002285 }
Damien Miller95def091999-11-25 00:26:21 +11002286 fclose(f);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002287}
2288
Damien Millere72b7af1999-12-30 15:08:44 +11002289#ifdef USE_PAM
2290/*
2291 * Sets any environment variables which have been specified by PAM
2292 */
2293void do_pam_environment(char ***env, int *envsize)
2294{
2295 char *equals, var_name[512], var_val[512];
2296 char **pam_env;
2297 int i;
2298
2299 if ((pam_env = fetch_pam_environment()) == NULL)
2300 return;
2301
2302 for(i = 0; pam_env[i] != NULL; i++) {
2303 if ((equals = strstr(pam_env[i], "=")) == NULL)
2304 continue;
2305
2306 if (strlen(pam_env[i]) < (sizeof(var_name) - 1))
2307 {
2308 memset(var_name, '\0', sizeof(var_name));
2309 memset(var_val, '\0', sizeof(var_val));
2310
2311 strncpy(var_name, pam_env[i], equals - pam_env[i]);
2312 strcpy(var_val, equals + 1);
2313
2314 debug("PAM environment: %s=%s", var_name, var_val);
2315
2316 child_set_env(env, envsize, var_name, var_val);
2317 }
2318 }
2319}
2320#endif /* USE_PAM */
2321
Damien Miller95def091999-11-25 00:26:21 +11002322/*
2323 * Performs common processing for the child, such as setting up the
2324 * environment, closing extra file descriptors, setting the user and group
2325 * ids, and executing the command or shell.
2326 */
2327void
2328do_child(const char *command, struct passwd * pw, const char *term,
2329 const char *display, const char *auth_proto,
2330 const char *auth_data, const char *ttyname)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002331{
Damien Miller95def091999-11-25 00:26:21 +11002332 const char *shell, *cp = NULL;
2333 char buf[256];
2334 FILE *f;
2335 unsigned int envsize, i;
2336 char **env;
2337 extern char **environ;
2338 struct stat st;
2339 char *argv[10];
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002340
Damien Millerbeb4ba51999-12-28 15:09:35 +11002341#ifndef USE_PAM /* pam_nologin handles this */
Damien Miller95def091999-11-25 00:26:21 +11002342 /* Check /etc/nologin. */
2343 f = fopen("/etc/nologin", "r");
2344 if (f) {
2345 /* /etc/nologin exists. Print its contents and exit. */
2346 while (fgets(buf, sizeof(buf), f))
2347 fputs(buf, stderr);
2348 fclose(f);
2349 if (pw->pw_uid != 0)
2350 exit(254);
2351 }
Damien Millerbeb4ba51999-12-28 15:09:35 +11002352#endif /* USE_PAM */
Damien Miller776af5d1999-11-12 08:49:09 +11002353
Damien Miller95def091999-11-25 00:26:21 +11002354 /* Set login name in the kernel. */
2355 if (setlogin(pw->pw_name) < 0)
2356 error("setlogin failed: %s", strerror(errno));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002357
Damien Miller95def091999-11-25 00:26:21 +11002358 /* Set uid, gid, and groups. */
2359 /* Login(1) does this as well, and it needs uid 0 for the "-h"
2360 switch, so we let login(1) to this for us. */
2361 if (!options.use_login) {
2362 if (getuid() == 0 || geteuid() == 0) {
2363 if (setgid(pw->pw_gid) < 0) {
2364 perror("setgid");
2365 exit(1);
2366 }
2367 /* Initialize the group list. */
2368 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
2369 perror("initgroups");
2370 exit(1);
2371 }
2372 endgrent();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002373
Damien Miller95def091999-11-25 00:26:21 +11002374 /* Permanently switch to the desired uid. */
2375 permanently_set_uid(pw->pw_uid);
2376 }
2377 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
2378 fatal("Failed to set uids to %d.", (int) pw->pw_uid);
2379 }
Damien Miller5428f641999-11-25 11:54:57 +11002380 /*
2381 * Get the shell from the password data. An empty shell field is
2382 * legal, and means /bin/sh.
2383 */
Damien Miller95def091999-11-25 00:26:21 +11002384 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002385
2386#ifdef AFS
Damien Miller95def091999-11-25 00:26:21 +11002387 /* Try to get AFS tokens for the local cell. */
2388 if (k_hasafs()) {
2389 char cell[64];
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002390
Damien Miller95def091999-11-25 00:26:21 +11002391 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
2392 krb_afslog(cell, 0);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002393
Damien Miller95def091999-11-25 00:26:21 +11002394 krb_afslog(0, 0);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002395 }
Damien Miller95def091999-11-25 00:26:21 +11002396#endif /* AFS */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002397
Damien Miller5428f641999-11-25 11:54:57 +11002398 /* Initialize the environment. */
Damien Miller95def091999-11-25 00:26:21 +11002399 envsize = 100;
2400 env = xmalloc(envsize * sizeof(char *));
2401 env[0] = NULL;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002402
Damien Miller95def091999-11-25 00:26:21 +11002403 if (!options.use_login) {
2404 /* Set basic environment. */
2405 child_set_env(&env, &envsize, "USER", pw->pw_name);
2406 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
2407 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
2408 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002409
Damien Miller95def091999-11-25 00:26:21 +11002410 snprintf(buf, sizeof buf, "%.200s/%.50s",
2411 _PATH_MAILDIR, pw->pw_name);
2412 child_set_env(&env, &envsize, "MAIL", buf);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002413
Damien Miller95def091999-11-25 00:26:21 +11002414 /* Normal systems set SHELL by default. */
2415 child_set_env(&env, &envsize, "SHELL", shell);
2416 }
Damien Miller95def091999-11-25 00:26:21 +11002417 if (getenv("TZ"))
2418 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
2419
2420 /* Set custom environment options from RSA authentication. */
2421 while (custom_environment) {
2422 struct envstring *ce = custom_environment;
2423 char *s = ce->s;
2424 int i;
2425 for (i = 0; s[i] != '=' && s[i]; i++);
2426 if (s[i] == '=') {
2427 s[i] = 0;
2428 child_set_env(&env, &envsize, s, s + i + 1);
2429 }
2430 custom_environment = ce->next;
2431 xfree(ce->s);
2432 xfree(ce);
2433 }
2434
Damien Miller95def091999-11-25 00:26:21 +11002435 snprintf(buf, sizeof buf, "%.50s %d %d",
Damien Miller34132e52000-01-14 15:45:46 +11002436 get_remote_ipaddr(), get_remote_port(), get_local_port());
Damien Miller95def091999-11-25 00:26:21 +11002437 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
2438
Damien Miller95def091999-11-25 00:26:21 +11002439 if (ttyname)
2440 child_set_env(&env, &envsize, "SSH_TTY", ttyname);
Damien Miller95def091999-11-25 00:26:21 +11002441 if (term)
2442 child_set_env(&env, &envsize, "TERM", term);
Damien Miller95def091999-11-25 00:26:21 +11002443 if (display)
2444 child_set_env(&env, &envsize, "DISPLAY", display);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002445
Damien Miller1fa154b2000-01-23 10:32:03 +11002446#ifdef _AIX
2447 {
2448 char *authstate,*krb5cc;
2449
2450 if ((authstate = getenv("AUTHSTATE")) != NULL)
2451 child_set_env(&env,&envsize,"AUTHSTATE",authstate);
2452
2453 if ((krb5cc = getenv("KRB5CCNAME")) != NULL)
2454 child_set_env(&env,&envsize,"KRB5CCNAME",krb5cc);
2455 }
2456#endif
2457
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002458#ifdef KRB4
Damien Miller95def091999-11-25 00:26:21 +11002459 {
2460 extern char *ticket;
2461
2462 if (ticket)
2463 child_set_env(&env, &envsize, "KRBTKFILE", ticket);
2464 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002465#endif /* KRB4 */
2466
Damien Millerbeb4ba51999-12-28 15:09:35 +11002467#ifdef USE_PAM
Damien Miller95def091999-11-25 00:26:21 +11002468 /* Pull in any environment variables that may have been set by PAM. */
Damien Millere72b7af1999-12-30 15:08:44 +11002469 do_pam_environment(&env, &envsize);
Damien Millerbeb4ba51999-12-28 15:09:35 +11002470#endif /* USE_PAM */
Damien Miller94388161999-10-29 09:57:31 +10002471
Damien Miller95def091999-11-25 00:26:21 +11002472 if (xauthfile)
2473 child_set_env(&env, &envsize, "XAUTHORITY", xauthfile);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002474
Damien Miller95def091999-11-25 00:26:21 +11002475 if (auth_get_socket_name() != NULL)
2476 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
2477 auth_get_socket_name());
Damien Miller776af5d1999-11-12 08:49:09 +11002478
Damien Miller1fa154b2000-01-23 10:32:03 +11002479 read_environment_file(&env,&envsize,"/etc/environment");
2480
Damien Miller5428f641999-11-25 11:54:57 +11002481 /* read $HOME/.ssh/environment. */
Damien Miller95def091999-11-25 00:26:21 +11002482 if (!options.use_login) {
2483 snprintf(buf, sizeof buf, "%.200s/.ssh/environment", pw->pw_dir);
2484 read_environment_file(&env, &envsize, buf);
2485 }
Damien Miller95def091999-11-25 00:26:21 +11002486 if (debug_flag) {
Damien Miller5428f641999-11-25 11:54:57 +11002487 /* dump the environment */
Damien Miller95def091999-11-25 00:26:21 +11002488 fprintf(stderr, "Environment:\n");
2489 for (i = 0; env[i]; i++)
2490 fprintf(stderr, " %.200s\n", env[i]);
2491 }
Damien Miller5428f641999-11-25 11:54:57 +11002492 /*
2493 * Close the connection descriptors; note that this is the child, and
2494 * the server will still have the socket open, and it is important
2495 * that we do not shutdown it. Note that the descriptors cannot be
2496 * closed before building the environment, as we call
2497 * get_remote_ipaddr there.
2498 */
Damien Miller95def091999-11-25 00:26:21 +11002499 if (packet_get_connection_in() == packet_get_connection_out())
2500 close(packet_get_connection_in());
2501 else {
2502 close(packet_get_connection_in());
2503 close(packet_get_connection_out());
2504 }
Damien Miller5428f641999-11-25 11:54:57 +11002505 /*
2506 * Close all descriptors related to channels. They will still remain
2507 * open in the parent.
2508 */
2509 /* XXX better use close-on-exec? -markus */
Damien Miller95def091999-11-25 00:26:21 +11002510 channel_close_all();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002511
Damien Miller5428f641999-11-25 11:54:57 +11002512 /*
2513 * Close any extra file descriptors. Note that there may still be
2514 * descriptors left by system functions. They will be closed later.
2515 */
Damien Miller95def091999-11-25 00:26:21 +11002516 endpwent();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002517
Damien Miller5428f641999-11-25 11:54:57 +11002518 /*
2519 * Close any extra open file descriptors so that we don\'t have them
2520 * hanging around in clients. Note that we want to do this after
2521 * initgroups, because at least on Solaris 2.3 it leaves file
2522 * descriptors open.
2523 */
Damien Miller95def091999-11-25 00:26:21 +11002524 for (i = 3; i < 64; i++)
2525 close(i);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002526
Damien Miller95def091999-11-25 00:26:21 +11002527 /* Change current directory to the user\'s home directory. */
2528 if (chdir(pw->pw_dir) < 0)
2529 fprintf(stderr, "Could not chdir to home directory %s: %s\n",
2530 pw->pw_dir, strerror(errno));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002531
Damien Miller5428f641999-11-25 11:54:57 +11002532 /*
2533 * Must take new environment into use so that .ssh/rc, /etc/sshrc and
2534 * xauth are run in the proper environment.
2535 */
Damien Miller95def091999-11-25 00:26:21 +11002536 environ = env;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002537
Damien Miller5428f641999-11-25 11:54:57 +11002538 /*
2539 * Run $HOME/.ssh/rc, /etc/sshrc, or xauth (whichever is found first
2540 * in this order).
2541 */
Damien Miller95def091999-11-25 00:26:21 +11002542 if (!options.use_login) {
2543 if (stat(SSH_USER_RC, &st) >= 0) {
2544 if (debug_flag)
2545 fprintf(stderr, "Running /bin/sh %s\n", SSH_USER_RC);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002546
Damien Miller95def091999-11-25 00:26:21 +11002547 f = popen("/bin/sh " SSH_USER_RC, "w");
2548 if (f) {
2549 if (auth_proto != NULL && auth_data != NULL)
2550 fprintf(f, "%s %s\n", auth_proto, auth_data);
2551 pclose(f);
2552 } else
2553 fprintf(stderr, "Could not run %s\n", SSH_USER_RC);
2554 } else if (stat(SSH_SYSTEM_RC, &st) >= 0) {
2555 if (debug_flag)
2556 fprintf(stderr, "Running /bin/sh %s\n", SSH_SYSTEM_RC);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002557
Damien Miller95def091999-11-25 00:26:21 +11002558 f = popen("/bin/sh " SSH_SYSTEM_RC, "w");
2559 if (f) {
2560 if (auth_proto != NULL && auth_data != NULL)
2561 fprintf(f, "%s %s\n", auth_proto, auth_data);
2562 pclose(f);
2563 } else
2564 fprintf(stderr, "Could not run %s\n", SSH_SYSTEM_RC);
2565 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002566#ifdef XAUTH_PATH
Damien Miller95def091999-11-25 00:26:21 +11002567 else {
Damien Miller5428f641999-11-25 11:54:57 +11002568 /* Add authority data to .Xauthority if appropriate. */
Damien Miller95def091999-11-25 00:26:21 +11002569 if (auth_proto != NULL && auth_data != NULL) {
2570 if (debug_flag)
2571 fprintf(stderr, "Running %.100s add %.100s %.100s %.100s\n",
2572 XAUTH_PATH, display, auth_proto, auth_data);
2573
2574 f = popen(XAUTH_PATH " -q -", "w");
2575 if (f) {
2576 fprintf(f, "add %s %s %s\n", display, auth_proto, auth_data);
2577 fclose(f);
2578 } else
2579 fprintf(stderr, "Could not run %s -q -\n", XAUTH_PATH);
2580 }
2581 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002582#endif /* XAUTH_PATH */
2583
Damien Miller95def091999-11-25 00:26:21 +11002584 /* Get the last component of the shell name. */
2585 cp = strrchr(shell, '/');
2586 if (cp)
2587 cp++;
2588 else
2589 cp = shell;
2590 }
Damien Miller5428f641999-11-25 11:54:57 +11002591 /*
2592 * If we have no command, execute the shell. In this case, the shell
2593 * name to be passed in argv[0] is preceded by '-' to indicate that
2594 * this is a login shell.
2595 */
Damien Miller95def091999-11-25 00:26:21 +11002596 if (!command) {
2597 if (!options.use_login) {
2598 char buf[256];
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002599
Damien Miller5428f641999-11-25 11:54:57 +11002600 /*
2601 * Check for mail if we have a tty and it was enabled
2602 * in server options.
2603 */
Damien Miller95def091999-11-25 00:26:21 +11002604 if (ttyname && options.check_mail) {
2605 char *mailbox;
2606 struct stat mailstat;
2607 mailbox = getenv("MAIL");
2608 if (mailbox != NULL) {
2609 if (stat(mailbox, &mailstat) != 0 || mailstat.st_size == 0)
2610 printf("No mail.\n");
2611 else if (mailstat.st_mtime < mailstat.st_atime)
2612 printf("You have mail.\n");
2613 else
2614 printf("You have new mail.\n");
2615 }
2616 }
2617 /* Start the shell. Set initial character to '-'. */
2618 buf[0] = '-';
2619 strncpy(buf + 1, cp, sizeof(buf) - 1);
2620 buf[sizeof(buf) - 1] = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002621
Damien Miller95def091999-11-25 00:26:21 +11002622 /* Execute the shell. */
2623 argv[0] = buf;
2624 argv[1] = NULL;
2625 execve(shell, argv, env);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002626
Damien Miller95def091999-11-25 00:26:21 +11002627 /* Executing the shell failed. */
2628 perror(shell);
2629 exit(1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002630
Damien Miller95def091999-11-25 00:26:21 +11002631 } else {
2632 /* Launch login(1). */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002633
Damien Miller95def091999-11-25 00:26:21 +11002634 execl(LOGIN_PROGRAM, "login", "-h", get_remote_ipaddr(),
2635 "-p", "-f", "--", pw->pw_name, NULL);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002636
Damien Miller95def091999-11-25 00:26:21 +11002637 /* Login couldn't be executed, die. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002638
Damien Miller95def091999-11-25 00:26:21 +11002639 perror("login");
2640 exit(1);
2641 }
2642 }
Damien Miller5428f641999-11-25 11:54:57 +11002643 /*
2644 * Execute the command using the user's shell. This uses the -c
2645 * option to execute the command.
2646 */
Damien Miller95def091999-11-25 00:26:21 +11002647 argv[0] = (char *) cp;
2648 argv[1] = "-c";
2649 argv[2] = (char *) command;
2650 argv[3] = NULL;
2651 execve(shell, argv, env);
2652 perror(shell);
2653 exit(1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002654}