1 /* $OpenBSD: sshd.c,v 1.485 2017/03/15 03:52:30 deraadt Exp $ */
2 /*
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
6 * This program is the ssh daemon. It listens for connections from clients,
7 * and 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
10 * authentication agent connections.
11 *
12 * As far as I am concerned, the code I have written for this software
13 * can be used freely for any purpose. Any derived versions of this
14 * software must be clearly marked as such, and if the derived work is
15 * incompatible with the protocol description in the RFC file, it must be
16 * called by a name other than "ssh" or "Secure Shell".
17 *
18 * SSH2 implementation:
19 * Privilege Separation:
20 *
21 * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved.
22 * Copyright (c) 2002 Niels Provos. All rights reserved.
23 *
24 * Redistribution and use in source and binary forms, with or without
25 * modification, are permitted provided that the following conditions
26 * are met:
27 * 1. Redistributions of source code must retain the above copyright
28 * notice, this list of conditions and the following disclaimer.
29 * 2. Redistributions in binary form must reproduce the above copyright
30 * notice, this list of conditions and the following disclaimer in the
31 * documentation and/or other materials provided with the distribution.
32 *
33 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
34 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
35 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
36 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
37 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
38 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
39 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
40 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
41 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
42 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
43 */
44
45 #include "includes.h"
46
47 #include <sys/types.h>
48 #include <sys/ioctl.h>
49 #include <sys/socket.h>
50 #ifdef HAVE_SYS_STAT_H
51 # include <sys/stat.h>
52 #endif
53 #ifdef HAVE_SYS_TIME_H
54 # include <sys/time.h>
55 #endif
56 #include "openbsd-compat/sys-tree.h"
57 #include "openbsd-compat/sys-queue.h"
58 #include <sys/wait.h>
59
60 #include <errno.h>
61 #include <fcntl.h>
62 #include <netdb.h>
63 #ifdef HAVE_PATHS_H
64 #include <paths.h>
65 #endif
66 #include <grp.h>
67 #include <pwd.h>
68 #include <signal.h>
69 #include <stdarg.h>
70 #include <stdio.h>
71 #include <stdlib.h>
72 #include <string.h>
73 #include <unistd.h>
74 #include <limits.h>
75
76 #ifdef WITH_OPENSSL
77 #include <openssl/dh.h>
78 #include <openssl/bn.h>
79 #include <openssl/rand.h>
80 #include "openbsd-compat/openssl-compat.h"
81 #endif
82
83 #ifdef HAVE_SECUREWARE
84 #include <sys/security.h>
85 #include <prot.h>
86 #endif
87
88 #include "xmalloc.h"
89 #include "ssh.h"
90 #include "ssh2.h"
91 #include "rsa.h"
92 #include "sshpty.h"
93 #include "packet.h"
94 #include "log.h"
95 #include "buffer.h"
96 #include "misc.h"
97 #include "match.h"
98 #include "servconf.h"
99 #include "uidswap.h"
100 #include "compat.h"
101 #include "cipher.h"
102 #include "digest.h"
103 #include "key.h"
104 #include "kex.h"
105 #include "myproposal.h"
106 #include "authfile.h"
107 #include "pathnames.h"
108 #include "atomicio.h"
109 #include "canohost.h"
110 #include "hostfile.h"
111 #include "auth.h"
112 #include "authfd.h"
113 #include "msg.h"
114 #include "dispatch.h"
115 #include "channels.h"
116 #include "session.h"
117 #include "monitor.h"
118 #ifdef GSSAPI
119 #include "ssh-gss.h"
120 #endif
121 #include "monitor_wrap.h"
122 #include "ssh-sandbox.h"
123 #include "version.h"
124 #include "ssherr.h"
125
126 /* Re-exec fds */
127 #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1)
128 #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2)
129 #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3)
130 #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4)
131
132 extern char *__progname;
133
134 /* Server configuration options. */
135 ServerOptions options;
136
137 /* Name of the server configuration file. */
138 char *config_file_name = _PATH_SERVER_CONFIG_FILE;
139
140 /*
141 * Debug mode flag. This can be set on the command line. If debug
142 * mode is enabled, extra debugging output will be sent to the system
143 * log, the daemon will not go to background, and will exit after processing
144 * the first connection.
145 */
146 int debug_flag = 0;
147
148 /* Flag indicating that the daemon should only test the configuration and keys. */
149 int test_flag = 0;
150
151 /* Flag indicating that the daemon is being started from inetd. */
152 int inetd_flag = 0;
153
154 /* Flag indicating that sshd should not detach and become a daemon. */
155 int no_daemon_flag = 0;
156
157 /* debug goes to stderr unless inetd_flag is set */
158 int log_stderr = 0;
159
160 /* Saved arguments to main(). */
161 char **saved_argv;
162 int saved_argc;
163
164 /* re-exec */
165 int rexeced_flag = 0;
166 int rexec_flag = 1;
167 int rexec_argc = 0;
168 char **rexec_argv;
169
170 /*
171 * The sockets that the server is listening; this is used in the SIGHUP
172 * signal handler.
173 */
174 #define MAX_LISTEN_SOCKS 16
175 int listen_socks[MAX_LISTEN_SOCKS];
176 int num_listen_socks = 0;
177
178 /*
179 * the client's version string, passed by sshd2 in compat mode. if != NULL,
180 * sshd will skip the version-number exchange
181 */
182 char *client_version_string = NULL;
183 char *server_version_string = NULL;
184
185 /* Daemon's agent connection */
186 int auth_sock = -1;
187 int have_agent = 0;
188
189 /*
190 * Any really sensitive data in the application is contained in this
191 * structure. The idea is that this structure could be locked into memory so
192 * that the pages do not get written into swap. However, there are some
193 * problems. The private key contains BIGNUMs, and we do not (in principle)
194 * have access to the internals of them, and locking just the structure is
195 * not very useful. Currently, memory locking is not implemented.
196 */
197 struct {
198 Key **host_keys; /* all private host keys */
199 Key **host_pubkeys; /* all public host keys */
200 Key **host_certificates; /* all public host certificates */
201 int have_ssh2_key;
202 } sensitive_data;
203
204 /* This is set to true when a signal is received. */
205 static volatile sig_atomic_t received_sighup = 0;
206 static volatile sig_atomic_t received_sigterm = 0;
207
208 /* session identifier, used by RSA-auth */
209 u_char session_id[16];
210
211 /* same for ssh2 */
212 u_char *session_id2 = NULL;
213 u_int session_id2_len = 0;
214
215 /* record remote hostname or ip */
216 u_int utmp_len = HOST_NAME_MAX+1;
217
218 /* options.max_startup sized array of fd ints */
219 int *startup_pipes = NULL;
220 int startup_pipe; /* in child */
221
222 /* variables used for privilege separation */
223 int use_privsep = -1;
224 struct monitor *pmonitor = NULL;
225 int privsep_is_preauth = 1;
226
227 /* global authentication context */
228 Authctxt *the_authctxt = NULL;
229
230 /* sshd_config buffer */
231 Buffer cfg;
232
233 /* message to be displayed after login */
234 Buffer loginmsg;
235
236 /* Unprivileged user */
237 struct passwd *privsep_pw = NULL;
238
239 /* Prototypes for various functions defined later in this file. */
240 void destroy_sensitive_data(void);
241 void demote_sensitive_data(void);
242 static void do_ssh2_kex(void);
243
244 /*
245 * Close all listening sockets
246 */
247 static void
close_listen_socks(void)248 close_listen_socks(void)
249 {
250 int i;
251
252 for (i = 0; i < num_listen_socks; i++)
253 close(listen_socks[i]);
254 num_listen_socks = -1;
255 }
256
257 static void
close_startup_pipes(void)258 close_startup_pipes(void)
259 {
260 int i;
261
262 if (startup_pipes)
263 for (i = 0; i < options.max_startups; i++)
264 if (startup_pipes[i] != -1)
265 close(startup_pipes[i]);
266 }
267
268 /*
269 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
270 * the effect is to reread the configuration file (and to regenerate
271 * the server key).
272 */
273
274 /*ARGSUSED*/
275 static void
sighup_handler(int sig)276 sighup_handler(int sig)
277 {
278 int save_errno = errno;
279
280 received_sighup = 1;
281 signal(SIGHUP, sighup_handler);
282 errno = save_errno;
283 }
284
285 /*
286 * Called from the main program after receiving SIGHUP.
287 * Restarts the server.
288 */
289 static void
sighup_restart(void)290 sighup_restart(void)
291 {
292 logit("Received SIGHUP; restarting.");
293 if (options.pid_file != NULL)
294 unlink(options.pid_file);
295 platform_pre_restart();
296 close_listen_socks();
297 close_startup_pipes();
298 alarm(0); /* alarm timer persists across exec */
299 signal(SIGHUP, SIG_IGN); /* will be restored after exec */
300 execv(saved_argv[0], saved_argv);
301 logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
302 strerror(errno));
303 exit(1);
304 }
305
306 /*
307 * Generic signal handler for terminating signals in the master daemon.
308 */
309 /*ARGSUSED*/
310 static void
sigterm_handler(int sig)311 sigterm_handler(int sig)
312 {
313 received_sigterm = sig;
314 }
315
316 /*
317 * SIGCHLD handler. This is called whenever a child dies. This will then
318 * reap any zombies left by exited children.
319 */
320 /*ARGSUSED*/
321 static void
main_sigchld_handler(int sig)322 main_sigchld_handler(int sig)
323 {
324 int save_errno = errno;
325 pid_t pid;
326 int status;
327
328 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
329 (pid < 0 && errno == EINTR))
330 ;
331
332 signal(SIGCHLD, main_sigchld_handler);
333 errno = save_errno;
334 }
335
336 /*
337 * Signal handler for the alarm after the login grace period has expired.
338 */
339 /*ARGSUSED*/
340 static void
grace_alarm_handler(int sig)341 grace_alarm_handler(int sig)
342 {
343 if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0)
344 kill(pmonitor->m_pid, SIGALRM);
345
346 /*
347 * Try to kill any processes that we have spawned, E.g. authorized
348 * keys command helpers.
349 */
350 if (getpgid(0) == getpid()) {
351 signal(SIGTERM, SIG_IGN);
352 kill(0, SIGTERM);
353 }
354
355 /* Log error and exit. */
356 sigdie("Timeout before authentication for %s port %d",
357 ssh_remote_ipaddr(active_state), ssh_remote_port(active_state));
358 }
359
360 static void
sshd_exchange_identification(struct ssh * ssh,int sock_in,int sock_out)361 sshd_exchange_identification(struct ssh *ssh, int sock_in, int sock_out)
362 {
363 u_int i;
364 int remote_major, remote_minor;
365 char *s;
366 char buf[256]; /* Must not be larger than remote_version. */
367 char remote_version[256]; /* Must be at least as big as buf. */
368
369 xasprintf(&server_version_string, "SSH-%d.%d-%.100s%s%s\r\n",
370 PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, SSH_VERSION,
371 *options.version_addendum == '\0' ? "" : " ",
372 options.version_addendum);
373
374 /* Send our protocol version identification. */
375 if (atomicio(vwrite, sock_out, server_version_string,
376 strlen(server_version_string))
377 != strlen(server_version_string)) {
378 logit("Could not write ident string to %s port %d",
379 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
380 cleanup_exit(255);
381 }
382
383 /* Read other sides version identification. */
384 memset(buf, 0, sizeof(buf));
385 for (i = 0; i < sizeof(buf) - 1; i++) {
386 if (atomicio(read, sock_in, &buf[i], 1) != 1) {
387 logit("Did not receive identification string "
388 "from %s port %d",
389 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
390 cleanup_exit(255);
391 }
392 if (buf[i] == '\r') {
393 buf[i] = 0;
394 /* Kludge for F-Secure Macintosh < 1.0.2 */
395 if (i == 12 &&
396 strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
397 break;
398 continue;
399 }
400 if (buf[i] == '\n') {
401 buf[i] = 0;
402 break;
403 }
404 }
405 buf[sizeof(buf) - 1] = 0;
406 client_version_string = xstrdup(buf);
407
408 /*
409 * Check that the versions match. In future this might accept
410 * several versions and set appropriate flags to handle them.
411 */
412 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
413 &remote_major, &remote_minor, remote_version) != 3) {
414 s = "Protocol mismatch.\n";
415 (void) atomicio(vwrite, sock_out, s, strlen(s));
416 logit("Bad protocol version identification '%.100s' "
417 "from %s port %d", client_version_string,
418 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
419 close(sock_in);
420 close(sock_out);
421 cleanup_exit(255);
422 }
423 debug("Client protocol version %d.%d; client software version %.100s",
424 remote_major, remote_minor, remote_version);
425
426 ssh->compat = compat_datafellows(remote_version);
427
428 if ((ssh->compat & SSH_BUG_PROBE) != 0) {
429 logit("probed from %s port %d with %s. Don't panic.",
430 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
431 client_version_string);
432 cleanup_exit(255);
433 }
434 if ((ssh->compat & SSH_BUG_SCANNER) != 0) {
435 logit("scanned from %s port %d with %s. Don't panic.",
436 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
437 client_version_string);
438 cleanup_exit(255);
439 }
440 if ((ssh->compat & SSH_BUG_RSASIGMD5) != 0) {
441 logit("Client version \"%.100s\" uses unsafe RSA signature "
442 "scheme; disabling use of RSA keys", remote_version);
443 }
444 if ((ssh->compat & SSH_BUG_DERIVEKEY) != 0) {
445 fatal("Client version \"%.100s\" uses unsafe key agreement; "
446 "refusing connection", remote_version);
447 }
448
449 chop(server_version_string);
450 debug("Local version string %.200s", server_version_string);
451
452 if (remote_major == 2 ||
453 (remote_major == 1 && remote_minor == 99)) {
454 enable_compat20();
455 } else {
456 s = "Protocol major versions differ.\n";
457 (void) atomicio(vwrite, sock_out, s, strlen(s));
458 close(sock_in);
459 close(sock_out);
460 logit("Protocol major versions differ for %s port %d: "
461 "%.200s vs. %.200s",
462 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
463 server_version_string, client_version_string);
464 cleanup_exit(255);
465 }
466 }
467
468 /* Destroy the host and server keys. They will no longer be needed. */
469 void
destroy_sensitive_data(void)470 destroy_sensitive_data(void)
471 {
472 int i;
473
474 for (i = 0; i < options.num_host_key_files; i++) {
475 if (sensitive_data.host_keys[i]) {
476 key_free(sensitive_data.host_keys[i]);
477 sensitive_data.host_keys[i] = NULL;
478 }
479 if (sensitive_data.host_certificates[i]) {
480 key_free(sensitive_data.host_certificates[i]);
481 sensitive_data.host_certificates[i] = NULL;
482 }
483 }
484 }
485
486 /* Demote private to public keys for network child */
487 void
demote_sensitive_data(void)488 demote_sensitive_data(void)
489 {
490 Key *tmp;
491 int i;
492
493 for (i = 0; i < options.num_host_key_files; i++) {
494 if (sensitive_data.host_keys[i]) {
495 tmp = key_demote(sensitive_data.host_keys[i]);
496 key_free(sensitive_data.host_keys[i]);
497 sensitive_data.host_keys[i] = tmp;
498 }
499 /* Certs do not need demotion */
500 }
501 }
502
503 static void
reseed_prngs(void)504 reseed_prngs(void)
505 {
506 u_int32_t rnd[256];
507
508 #ifdef WITH_OPENSSL
509 RAND_poll();
510 #endif
511 arc4random_stir(); /* noop on recent arc4random() implementations */
512 arc4random_buf(rnd, sizeof(rnd)); /* let arc4random notice PID change */
513
514 #ifdef WITH_OPENSSL
515 RAND_seed(rnd, sizeof(rnd));
516 /* give libcrypto a chance to notice the PID change */
517 if ((RAND_bytes((u_char *)rnd, 1)) != 1)
518 fatal("%s: RAND_bytes failed", __func__);
519 #endif
520
521 explicit_bzero(rnd, sizeof(rnd));
522 }
523
524 static void
privsep_preauth_child(void)525 privsep_preauth_child(void)
526 {
527 gid_t gidset[1];
528
529 /* Enable challenge-response authentication for privilege separation */
530 privsep_challenge_enable();
531
532 #ifdef GSSAPI
533 /* Cache supported mechanism OIDs for later use */
534 if (options.gss_authentication)
535 ssh_gssapi_prepare_supported_oids();
536 #endif
537
538 reseed_prngs();
539
540 /* Demote the private keys to public keys. */
541 demote_sensitive_data();
542
543 /* Demote the child */
544 if (getuid() == 0 || geteuid() == 0) {
545 /* Change our root directory */
546 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
547 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
548 strerror(errno));
549 if (chdir("/") == -1)
550 fatal("chdir(\"/\"): %s", strerror(errno));
551
552 /* Drop our privileges */
553 debug3("privsep user:group %u:%u", (u_int)privsep_pw->pw_uid,
554 (u_int)privsep_pw->pw_gid);
555 gidset[0] = privsep_pw->pw_gid;
556 if (setgroups(1, gidset) < 0)
557 fatal("setgroups: %.100s", strerror(errno));
558 permanently_set_uid(privsep_pw);
559 }
560 }
561
562 static int
privsep_preauth(Authctxt * authctxt)563 privsep_preauth(Authctxt *authctxt)
564 {
565 int status, r;
566 pid_t pid;
567 struct ssh_sandbox *box = NULL;
568
569 /* Set up unprivileged child process to deal with network data */
570 pmonitor = monitor_init();
571 /* Store a pointer to the kex for later rekeying */
572 pmonitor->m_pkex = &active_state->kex;
573
574 if (use_privsep == PRIVSEP_ON)
575 box = ssh_sandbox_init(pmonitor);
576 pid = fork();
577 if (pid == -1) {
578 fatal("fork of unprivileged child failed");
579 } else if (pid != 0) {
580 debug2("Network child is on pid %ld", (long)pid);
581
582 pmonitor->m_pid = pid;
583 if (have_agent) {
584 r = ssh_get_authentication_socket(&auth_sock);
585 if (r != 0) {
586 error("Could not get agent socket: %s",
587 ssh_err(r));
588 have_agent = 0;
589 }
590 }
591 if (box != NULL)
592 ssh_sandbox_parent_preauth(box, pid);
593 monitor_child_preauth(authctxt, pmonitor);
594
595 /* Wait for the child's exit status */
596 while (waitpid(pid, &status, 0) < 0) {
597 if (errno == EINTR)
598 continue;
599 pmonitor->m_pid = -1;
600 fatal("%s: waitpid: %s", __func__, strerror(errno));
601 }
602 privsep_is_preauth = 0;
603 pmonitor->m_pid = -1;
604 if (WIFEXITED(status)) {
605 if (WEXITSTATUS(status) != 0)
606 fatal("%s: preauth child exited with status %d",
607 __func__, WEXITSTATUS(status));
608 } else if (WIFSIGNALED(status))
609 fatal("%s: preauth child terminated by signal %d",
610 __func__, WTERMSIG(status));
611 if (box != NULL)
612 ssh_sandbox_parent_finish(box);
613 return 1;
614 } else {
615 /* child */
616 close(pmonitor->m_sendfd);
617 close(pmonitor->m_log_recvfd);
618
619 /* Arrange for logging to be sent to the monitor */
620 set_log_handler(mm_log_handler, pmonitor);
621
622 privsep_preauth_child();
623 setproctitle("%s", "[net]");
624 if (box != NULL)
625 ssh_sandbox_child(box);
626
627 return 0;
628 }
629 }
630
631 static void
privsep_postauth(Authctxt * authctxt)632 privsep_postauth(Authctxt *authctxt)
633 {
634 #ifdef DISABLE_FD_PASSING
635 if (1) {
636 #else
637 if (authctxt->pw->pw_uid == 0) {
638 #endif
639 /* File descriptor passing is broken or root login */
640 use_privsep = 0;
641 goto skip;
642 }
643
644 /* New socket pair */
645 monitor_reinit(pmonitor);
646
647 pmonitor->m_pid = fork();
648 if (pmonitor->m_pid == -1)
649 fatal("fork of unprivileged child failed");
650 else if (pmonitor->m_pid != 0) {
651 verbose("User child is on pid %ld", (long)pmonitor->m_pid);
652 buffer_clear(&loginmsg);
653 monitor_child_postauth(pmonitor);
654
655 /* NEVERREACHED */
656 exit(0);
657 }
658
659 /* child */
660
661 close(pmonitor->m_sendfd);
662 pmonitor->m_sendfd = -1;
663
664 /* Demote the private keys to public keys. */
665 demote_sensitive_data();
666
667 reseed_prngs();
668
669 /* Drop privileges */
670 do_setusercontext(authctxt->pw);
671
672 skip:
673 /* It is safe now to apply the key state */
674 monitor_apply_keystate(pmonitor);
675
676 /*
677 * Tell the packet layer that authentication was successful, since
678 * this information is not part of the key state.
679 */
680 packet_set_authenticated();
681 }
682
683 static char *
684 list_hostkey_types(void)
685 {
686 Buffer b;
687 const char *p;
688 char *ret;
689 int i;
690 Key *key;
691
692 buffer_init(&b);
693 for (i = 0; i < options.num_host_key_files; i++) {
694 key = sensitive_data.host_keys[i];
695 if (key == NULL)
696 key = sensitive_data.host_pubkeys[i];
697 if (key == NULL)
698 continue;
699 /* Check that the key is accepted in HostkeyAlgorithms */
700 if (match_pattern_list(sshkey_ssh_name(key),
701 options.hostkeyalgorithms, 0) != 1) {
702 debug3("%s: %s key not permitted by HostkeyAlgorithms",
703 __func__, sshkey_ssh_name(key));
704 continue;
705 }
706 switch (key->type) {
707 case KEY_RSA:
708 case KEY_DSA:
709 case KEY_ECDSA:
710 case KEY_ED25519:
711 if (buffer_len(&b) > 0)
712 buffer_append(&b, ",", 1);
713 p = key_ssh_name(key);
714 buffer_append(&b, p, strlen(p));
715
716 /* for RSA we also support SHA2 signatures */
717 if (key->type == KEY_RSA) {
718 p = ",rsa-sha2-512,rsa-sha2-256";
719 buffer_append(&b, p, strlen(p));
720 }
721 break;
722 }
723 /* If the private key has a cert peer, then list that too */
724 key = sensitive_data.host_certificates[i];
725 if (key == NULL)
726 continue;
727 switch (key->type) {
728 case KEY_RSA_CERT:
729 case KEY_DSA_CERT:
730 case KEY_ECDSA_CERT:
731 case KEY_ED25519_CERT:
732 if (buffer_len(&b) > 0)
733 buffer_append(&b, ",", 1);
734 p = key_ssh_name(key);
735 buffer_append(&b, p, strlen(p));
736 break;
737 }
738 }
739 if ((ret = sshbuf_dup_string(&b)) == NULL)
740 fatal("%s: sshbuf_dup_string failed", __func__);
741 buffer_free(&b);
742 debug("list_hostkey_types: %s", ret);
743 return ret;
744 }
745
746 static Key *
747 get_hostkey_by_type(int type, int nid, int need_private, struct ssh *ssh)
748 {
749 int i;
750 Key *key;
751
752 for (i = 0; i < options.num_host_key_files; i++) {
753 switch (type) {
754 case KEY_RSA_CERT:
755 case KEY_DSA_CERT:
756 case KEY_ECDSA_CERT:
757 case KEY_ED25519_CERT:
758 key = sensitive_data.host_certificates[i];
759 break;
760 default:
761 key = sensitive_data.host_keys[i];
762 if (key == NULL && !need_private)
763 key = sensitive_data.host_pubkeys[i];
764 break;
765 }
766 if (key != NULL && key->type == type &&
767 (key->type != KEY_ECDSA || key->ecdsa_nid == nid))
768 return need_private ?
769 sensitive_data.host_keys[i] : key;
770 }
771 return NULL;
772 }
773
774 Key *
775 get_hostkey_public_by_type(int type, int nid, struct ssh *ssh)
776 {
777 return get_hostkey_by_type(type, nid, 0, ssh);
778 }
779
780 Key *
781 get_hostkey_private_by_type(int type, int nid, struct ssh *ssh)
782 {
783 return get_hostkey_by_type(type, nid, 1, ssh);
784 }
785
786 Key *
787 get_hostkey_by_index(int ind)
788 {
789 if (ind < 0 || ind >= options.num_host_key_files)
790 return (NULL);
791 return (sensitive_data.host_keys[ind]);
792 }
793
794 Key *
795 get_hostkey_public_by_index(int ind, struct ssh *ssh)
796 {
797 if (ind < 0 || ind >= options.num_host_key_files)
798 return (NULL);
799 return (sensitive_data.host_pubkeys[ind]);
800 }
801
802 int
803 get_hostkey_index(Key *key, int compare, struct ssh *ssh)
804 {
805 int i;
806
807 for (i = 0; i < options.num_host_key_files; i++) {
808 if (key_is_cert(key)) {
809 if (key == sensitive_data.host_certificates[i] ||
810 (compare && sensitive_data.host_certificates[i] &&
811 sshkey_equal(key,
812 sensitive_data.host_certificates[i])))
813 return (i);
814 } else {
815 if (key == sensitive_data.host_keys[i] ||
816 (compare && sensitive_data.host_keys[i] &&
817 sshkey_equal(key, sensitive_data.host_keys[i])))
818 return (i);
819 if (key == sensitive_data.host_pubkeys[i] ||
820 (compare && sensitive_data.host_pubkeys[i] &&
821 sshkey_equal(key, sensitive_data.host_pubkeys[i])))
822 return (i);
823 }
824 }
825 return (-1);
826 }
827
828 /* Inform the client of all hostkeys */
829 static void
830 notify_hostkeys(struct ssh *ssh)
831 {
832 struct sshbuf *buf;
833 struct sshkey *key;
834 int i, nkeys, r;
835 char *fp;
836
837 /* Some clients cannot cope with the hostkeys message, skip those. */
838 if (datafellows & SSH_BUG_HOSTKEYS)
839 return;
840
841 if ((buf = sshbuf_new()) == NULL)
842 fatal("%s: sshbuf_new", __func__);
843 for (i = nkeys = 0; i < options.num_host_key_files; i++) {
844 key = get_hostkey_public_by_index(i, ssh);
845 if (key == NULL || key->type == KEY_UNSPEC ||
846 sshkey_is_cert(key))
847 continue;
848 fp = sshkey_fingerprint(key, options.fingerprint_hash,
849 SSH_FP_DEFAULT);
850 debug3("%s: key %d: %s %s", __func__, i,
851 sshkey_ssh_name(key), fp);
852 free(fp);
853 if (nkeys == 0) {
854 packet_start(SSH2_MSG_GLOBAL_REQUEST);
855 packet_put_cstring("hostkeys-00@openssh.com");
856 packet_put_char(0); /* want-reply */
857 }
858 sshbuf_reset(buf);
859 if ((r = sshkey_putb(key, buf)) != 0)
860 fatal("%s: couldn't put hostkey %d: %s",
861 __func__, i, ssh_err(r));
862 packet_put_string(sshbuf_ptr(buf), sshbuf_len(buf));
863 nkeys++;
864 }
865 debug3("%s: sent %d hostkeys", __func__, nkeys);
866 if (nkeys == 0)
867 fatal("%s: no hostkeys", __func__);
868 packet_send();
869 sshbuf_free(buf);
870 }
871
872 /*
873 * returns 1 if connection should be dropped, 0 otherwise.
874 * dropping starts at connection #max_startups_begin with a probability
875 * of (max_startups_rate/100). the probability increases linearly until
876 * all connections are dropped for startups > max_startups
877 */
878 static int
879 drop_connection(int startups)
880 {
881 int p, r;
882
883 if (startups < options.max_startups_begin)
884 return 0;
885 if (startups >= options.max_startups)
886 return 1;
887 if (options.max_startups_rate == 100)
888 return 1;
889
890 p = 100 - options.max_startups_rate;
891 p *= startups - options.max_startups_begin;
892 p /= options.max_startups - options.max_startups_begin;
893 p += options.max_startups_rate;
894 r = arc4random_uniform(100);
895
896 debug("drop_connection: p %d, r %d", p, r);
897 return (r < p) ? 1 : 0;
898 }
899
900 static void
901 usage(void)
902 {
903 fprintf(stderr, "%s, %s\n",
904 SSH_RELEASE,
905 #ifdef WITH_OPENSSL
906 SSLeay_version(SSLEAY_VERSION)
907 #else
908 "without OpenSSL"
909 #endif
910 );
911 fprintf(stderr,
912 "usage: sshd [-46DdeiqTt] [-C connection_spec] [-c host_cert_file]\n"
913 " [-E log_file] [-f config_file] [-g login_grace_time]\n"
914 " [-h host_key_file] [-o option] [-p port] [-u len]\n"
915 );
916 exit(1);
917 }
918
919 static void
920 send_rexec_state(int fd, struct sshbuf *conf)
921 {
922 struct sshbuf *m;
923 int r;
924
925 debug3("%s: entering fd = %d config len %zu", __func__, fd,
926 sshbuf_len(conf));
927
928 /*
929 * Protocol from reexec master to child:
930 * string configuration
931 * string rngseed (only if OpenSSL is not self-seeded)
932 */
933 if ((m = sshbuf_new()) == NULL)
934 fatal("%s: sshbuf_new failed", __func__);
935 if ((r = sshbuf_put_stringb(m, conf)) != 0)
936 fatal("%s: buffer error: %s", __func__, ssh_err(r));
937
938 #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY)
939 rexec_send_rng_seed(m);
940 #endif
941
942 if (ssh_msg_send(fd, 0, m) == -1)
943 fatal("%s: ssh_msg_send failed", __func__);
944
945 sshbuf_free(m);
946
947 debug3("%s: done", __func__);
948 }
949
950 static void
951 recv_rexec_state(int fd, Buffer *conf)
952 {
953 Buffer m;
954 char *cp;
955 u_int len;
956
957 debug3("%s: entering fd = %d", __func__, fd);
958
959 buffer_init(&m);
960
961 if (ssh_msg_recv(fd, &m) == -1)
962 fatal("%s: ssh_msg_recv failed", __func__);
963 if (buffer_get_char(&m) != 0)
964 fatal("%s: rexec version mismatch", __func__);
965
966 cp = buffer_get_string(&m, &len);
967 if (conf != NULL)
968 buffer_append(conf, cp, len);
969 free(cp);
970
971 #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY)
972 rexec_recv_rng_seed(&m);
973 #endif
974
975 buffer_free(&m);
976
977 debug3("%s: done", __func__);
978 }
979
980 /* Accept a connection from inetd */
981 static void
982 server_accept_inetd(int *sock_in, int *sock_out)
983 {
984 int fd;
985
986 startup_pipe = -1;
987 if (rexeced_flag) {
988 close(REEXEC_CONFIG_PASS_FD);
989 *sock_in = *sock_out = dup(STDIN_FILENO);
990 if (!debug_flag) {
991 startup_pipe = dup(REEXEC_STARTUP_PIPE_FD);
992 close(REEXEC_STARTUP_PIPE_FD);
993 }
994 } else {
995 *sock_in = dup(STDIN_FILENO);
996 *sock_out = dup(STDOUT_FILENO);
997 }
998 /*
999 * We intentionally do not close the descriptors 0, 1, and 2
1000 * as our code for setting the descriptors won't work if
1001 * ttyfd happens to be one of those.
1002 */
1003 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1004 dup2(fd, STDIN_FILENO);
1005 dup2(fd, STDOUT_FILENO);
1006 if (!log_stderr)
1007 dup2(fd, STDERR_FILENO);
1008 if (fd > (log_stderr ? STDERR_FILENO : STDOUT_FILENO))
1009 close(fd);
1010 }
1011 debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out);
1012 }
1013
1014 /*
1015 * Listen for TCP connections
1016 */
1017 static void
1018 server_listen(void)
1019 {
1020 int ret, listen_sock, on = 1;
1021 struct addrinfo *ai;
1022 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1023
1024 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
1025 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1026 continue;
1027 if (num_listen_socks >= MAX_LISTEN_SOCKS)
1028 fatal("Too many listen sockets. "
1029 "Enlarge MAX_LISTEN_SOCKS");
1030 if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen,
1031 ntop, sizeof(ntop), strport, sizeof(strport),
1032 NI_NUMERICHOST|NI_NUMERICSERV)) != 0) {
1033 error("getnameinfo failed: %.100s",
1034 ssh_gai_strerror(ret));
1035 continue;
1036 }
1037 /* Create socket for listening. */
1038 listen_sock = socket(ai->ai_family, ai->ai_socktype,
1039 ai->ai_protocol);
1040 if (listen_sock < 0) {
1041 /* kernel may not support ipv6 */
1042 verbose("socket: %.100s", strerror(errno));
1043 continue;
1044 }
1045 if (set_nonblock(listen_sock) == -1) {
1046 close(listen_sock);
1047 continue;
1048 }
1049 if (fcntl(listen_sock, F_SETFD, FD_CLOEXEC) == -1) {
1050 verbose("socket: CLOEXEC: %s", strerror(errno));
1051 close(listen_sock);
1052 continue;
1053 }
1054 /*
1055 * Set socket options.
1056 * Allow local port reuse in TIME_WAIT.
1057 */
1058 if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
1059 &on, sizeof(on)) == -1)
1060 error("setsockopt SO_REUSEADDR: %s", strerror(errno));
1061
1062 /* Only communicate in IPv6 over AF_INET6 sockets. */
1063 if (ai->ai_family == AF_INET6)
1064 sock_set_v6only(listen_sock);
1065
1066 debug("Bind to port %s on %s.", strport, ntop);
1067
1068 /* Bind the socket to the desired port. */
1069 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1070 error("Bind to port %s on %s failed: %.200s.",
1071 strport, ntop, strerror(errno));
1072 close(listen_sock);
1073 continue;
1074 }
1075 listen_socks[num_listen_socks] = listen_sock;
1076 num_listen_socks++;
1077
1078 /* Start listening on the port. */
1079 if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0)
1080 fatal("listen on [%s]:%s: %.100s",
1081 ntop, strport, strerror(errno));
1082 logit("Server listening on %s port %s.", ntop, strport);
1083 }
1084 freeaddrinfo(options.listen_addrs);
1085
1086 if (!num_listen_socks)
1087 fatal("Cannot bind any address.");
1088 }
1089
1090 /*
1091 * The main TCP accept loop. Note that, for the non-debug case, returns
1092 * from this function are in a forked subprocess.
1093 */
1094 static void
1095 server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
1096 {
1097 fd_set *fdset;
1098 int i, j, ret, maxfd;
1099 int startups = 0;
1100 int startup_p[2] = { -1 , -1 };
1101 struct sockaddr_storage from;
1102 socklen_t fromlen;
1103 pid_t pid;
1104 u_char rnd[256];
1105
1106 /* setup fd set for accept */
1107 fdset = NULL;
1108 maxfd = 0;
1109 for (i = 0; i < num_listen_socks; i++)
1110 if (listen_socks[i] > maxfd)
1111 maxfd = listen_socks[i];
1112 /* pipes connected to unauthenticated childs */
1113 startup_pipes = xcalloc(options.max_startups, sizeof(int));
1114 for (i = 0; i < options.max_startups; i++)
1115 startup_pipes[i] = -1;
1116
1117 /*
1118 * Stay listening for connections until the system crashes or
1119 * the daemon is killed with a signal.
1120 */
1121 for (;;) {
1122 if (received_sighup)
1123 sighup_restart();
1124 free(fdset);
1125 fdset = xcalloc(howmany(maxfd + 1, NFDBITS),
1126 sizeof(fd_mask));
1127
1128 for (i = 0; i < num_listen_socks; i++)
1129 FD_SET(listen_socks[i], fdset);
1130 for (i = 0; i < options.max_startups; i++)
1131 if (startup_pipes[i] != -1)
1132 FD_SET(startup_pipes[i], fdset);
1133
1134 /* Wait in select until there is a connection. */
1135 ret = select(maxfd+1, fdset, NULL, NULL, NULL);
1136 if (ret < 0 && errno != EINTR)
1137 error("select: %.100s", strerror(errno));
1138 if (received_sigterm) {
1139 logit("Received signal %d; terminating.",
1140 (int) received_sigterm);
1141 close_listen_socks();
1142 if (options.pid_file != NULL)
1143 unlink(options.pid_file);
1144 exit(received_sigterm == SIGTERM ? 0 : 255);
1145 }
1146 if (ret < 0)
1147 continue;
1148
1149 for (i = 0; i < options.max_startups; i++)
1150 if (startup_pipes[i] != -1 &&
1151 FD_ISSET(startup_pipes[i], fdset)) {
1152 /*
1153 * the read end of the pipe is ready
1154 * if the child has closed the pipe
1155 * after successful authentication
1156 * or if the child has died
1157 */
1158 close(startup_pipes[i]);
1159 startup_pipes[i] = -1;
1160 startups--;
1161 }
1162 for (i = 0; i < num_listen_socks; i++) {
1163 if (!FD_ISSET(listen_socks[i], fdset))
1164 continue;
1165 fromlen = sizeof(from);
1166 *newsock = accept(listen_socks[i],
1167 (struct sockaddr *)&from, &fromlen);
1168 if (*newsock < 0) {
1169 if (errno != EINTR && errno != EWOULDBLOCK &&
1170 errno != ECONNABORTED && errno != EAGAIN)
1171 error("accept: %.100s",
1172 strerror(errno));
1173 if (errno == EMFILE || errno == ENFILE)
1174 usleep(100 * 1000);
1175 continue;
1176 }
1177 if (unset_nonblock(*newsock) == -1) {
1178 close(*newsock);
1179 continue;
1180 }
1181 if (drop_connection(startups) == 1) {
1182 char *laddr = get_local_ipaddr(*newsock);
1183 char *raddr = get_peer_ipaddr(*newsock);
1184
1185 verbose("drop connection #%d from [%s]:%d "
1186 "on [%s]:%d past MaxStartups", startups,
1187 raddr, get_peer_port(*newsock),
1188 laddr, get_local_port(*newsock));
1189 free(laddr);
1190 free(raddr);
1191 close(*newsock);
1192 continue;
1193 }
1194 if (pipe(startup_p) == -1) {
1195 close(*newsock);
1196 continue;
1197 }
1198
1199 if (rexec_flag && socketpair(AF_UNIX,
1200 SOCK_STREAM, 0, config_s) == -1) {
1201 error("reexec socketpair: %s",
1202 strerror(errno));
1203 close(*newsock);
1204 close(startup_p[0]);
1205 close(startup_p[1]);
1206 continue;
1207 }
1208
1209 for (j = 0; j < options.max_startups; j++)
1210 if (startup_pipes[j] == -1) {
1211 startup_pipes[j] = startup_p[0];
1212 if (maxfd < startup_p[0])
1213 maxfd = startup_p[0];
1214 startups++;
1215 break;
1216 }
1217
1218 /*
1219 * Got connection. Fork a child to handle it, unless
1220 * we are in debugging mode.
1221 */
1222 if (debug_flag) {
1223 /*
1224 * In debugging mode. Close the listening
1225 * socket, and start processing the
1226 * connection without forking.
1227 */
1228 debug("Server will not fork when running in debugging mode.");
1229 close_listen_socks();
1230 *sock_in = *newsock;
1231 *sock_out = *newsock;
1232 close(startup_p[0]);
1233 close(startup_p[1]);
1234 startup_pipe = -1;
1235 pid = getpid();
1236 if (rexec_flag) {
1237 send_rexec_state(config_s[0],
1238 &cfg);
1239 close(config_s[0]);
1240 }
1241 break;
1242 }
1243
1244 /*
1245 * Normal production daemon. Fork, and have
1246 * the child process the connection. The
1247 * parent continues listening.
1248 */
1249 platform_pre_fork();
1250 if ((pid = fork()) == 0) {
1251 /*
1252 * Child. Close the listening and
1253 * max_startup sockets. Start using
1254 * the accepted socket. Reinitialize
1255 * logging (since our pid has changed).
1256 * We break out of the loop to handle
1257 * the connection.
1258 */
1259 platform_post_fork_child();
1260 startup_pipe = startup_p[1];
1261 close_startup_pipes();
1262 close_listen_socks();
1263 *sock_in = *newsock;
1264 *sock_out = *newsock;
1265 log_init(__progname,
1266 options.log_level,
1267 options.log_facility,
1268 log_stderr);
1269 if (rexec_flag)
1270 close(config_s[0]);
1271 break;
1272 }
1273
1274 /* Parent. Stay in the loop. */
1275 platform_post_fork_parent(pid);
1276 if (pid < 0)
1277 error("fork: %.100s", strerror(errno));
1278 else
1279 debug("Forked child %ld.", (long)pid);
1280
1281 close(startup_p[1]);
1282
1283 if (rexec_flag) {
1284 send_rexec_state(config_s[0], &cfg);
1285 close(config_s[0]);
1286 close(config_s[1]);
1287 }
1288 close(*newsock);
1289
1290 /*
1291 * Ensure that our random state differs
1292 * from that of the child
1293 */
1294 arc4random_stir();
1295 arc4random_buf(rnd, sizeof(rnd));
1296 #ifdef WITH_OPENSSL
1297 RAND_seed(rnd, sizeof(rnd));
1298 if ((RAND_bytes((u_char *)rnd, 1)) != 1)
1299 fatal("%s: RAND_bytes failed", __func__);
1300 #endif
1301 explicit_bzero(rnd, sizeof(rnd));
1302 }
1303
1304 /* child process check (or debug mode) */
1305 if (num_listen_socks < 0)
1306 break;
1307 }
1308 }
1309
1310 /*
1311 * If IP options are supported, make sure there are none (log and
1312 * return an error if any are found). Basically we are worried about
1313 * source routing; it can be used to pretend you are somebody
1314 * (ip-address) you are not. That itself may be "almost acceptable"
1315 * under certain circumstances, but rhosts autentication is useless
1316 * if source routing is accepted. Notice also that if we just dropped
1317 * source routing here, the other side could use IP spoofing to do
1318 * rest of the interaction and could still bypass security. So we
1319 * exit here if we detect any IP options.
1320 */
1321 static void
1322 check_ip_options(struct ssh *ssh)
1323 {
1324 #ifdef IP_OPTIONS
1325 int sock_in = ssh_packet_get_connection_in(ssh);
1326 struct sockaddr_storage from;
1327 u_char opts[200];
1328 socklen_t i, option_size = sizeof(opts), fromlen = sizeof(from);
1329 char text[sizeof(opts) * 3 + 1];
1330
1331 memset(&from, 0, sizeof(from));
1332 if (getpeername(sock_in, (struct sockaddr *)&from,
1333 &fromlen) < 0)
1334 return;
1335 if (from.ss_family != AF_INET)
1336 return;
1337 /* XXX IPv6 options? */
1338
1339 if (getsockopt(sock_in, IPPROTO_IP, IP_OPTIONS, opts,
1340 &option_size) >= 0 && option_size != 0) {
1341 text[0] = '\0';
1342 for (i = 0; i < option_size; i++)
1343 snprintf(text + i*3, sizeof(text) - i*3,
1344 " %2.2x", opts[i]);
1345 fatal("Connection from %.100s port %d with IP opts: %.800s",
1346 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), text);
1347 }
1348 return;
1349 #endif /* IP_OPTIONS */
1350 }
1351
1352 /*
1353 * Main program for the daemon.
1354 */
1355 int
1356 main(int ac, char **av)
1357 {
1358 struct ssh *ssh = NULL;
1359 extern char *optarg;
1360 extern int optind;
1361 int r, opt, i, j, on = 1, already_daemon;
1362 int sock_in = -1, sock_out = -1, newsock = -1;
1363 const char *remote_ip;
1364 int remote_port;
1365 char *fp, *line, *laddr, *logfile = NULL;
1366 int config_s[2] = { -1 , -1 };
1367 u_int n;
1368 u_int64_t ibytes, obytes;
1369 mode_t new_umask;
1370 Key *key;
1371 Key *pubkey;
1372 int keytype;
1373 Authctxt *authctxt;
1374 struct connection_info *connection_info = get_connection_info(0, 0);
1375
1376 ssh_malloc_init(); /* must be called before any mallocs */
1377
1378 #ifdef HAVE_SECUREWARE
1379 (void)set_auth_parameters(ac, av);
1380 #endif
1381 __progname = ssh_get_progname(av[0]);
1382
1383 /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */
1384 saved_argc = ac;
1385 rexec_argc = ac;
1386 saved_argv = xcalloc(ac + 1, sizeof(*saved_argv));
1387 for (i = 0; i < ac; i++)
1388 saved_argv[i] = xstrdup(av[i]);
1389 saved_argv[i] = NULL;
1390
1391 #ifndef HAVE_SETPROCTITLE
1392 /* Prepare for later setproctitle emulation */
1393 compat_init_setproctitle(ac, av);
1394 av = saved_argv;
1395 #endif
1396
1397 if (geteuid() == 0 && setgroups(0, NULL) == -1)
1398 debug("setgroups(): %.200s", strerror(errno));
1399
1400 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1401 sanitise_stdfd();
1402
1403 /* Initialize configuration options to their default values. */
1404 initialize_server_options(&options);
1405
1406 /* Parse command-line arguments. */
1407 while ((opt = getopt(ac, av,
1408 "C:E:b:c:f:g:h:k:o:p:u:46DQRTdeiqrt")) != -1) {
1409 switch (opt) {
1410 case '4':
1411 options.address_family = AF_INET;
1412 break;
1413 case '6':
1414 options.address_family = AF_INET6;
1415 break;
1416 case 'f':
1417 config_file_name = optarg;
1418 break;
1419 case 'c':
1420 if (options.num_host_cert_files >= MAX_HOSTCERTS) {
1421 fprintf(stderr, "too many host certificates.\n");
1422 exit(1);
1423 }
1424 options.host_cert_files[options.num_host_cert_files++] =
1425 derelativise_path(optarg);
1426 break;
1427 case 'd':
1428 if (debug_flag == 0) {
1429 debug_flag = 1;
1430 options.log_level = SYSLOG_LEVEL_DEBUG1;
1431 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
1432 options.log_level++;
1433 break;
1434 case 'D':
1435 no_daemon_flag = 1;
1436 break;
1437 case 'E':
1438 logfile = optarg;
1439 /* FALLTHROUGH */
1440 case 'e':
1441 log_stderr = 1;
1442 break;
1443 case 'i':
1444 inetd_flag = 1;
1445 break;
1446 case 'r':
1447 rexec_flag = 0;
1448 break;
1449 case 'R':
1450 rexeced_flag = 1;
1451 inetd_flag = 1;
1452 break;
1453 case 'Q':
1454 /* ignored */
1455 break;
1456 case 'q':
1457 options.log_level = SYSLOG_LEVEL_QUIET;
1458 break;
1459 case 'b':
1460 /* protocol 1, ignored */
1461 break;
1462 case 'p':
1463 options.ports_from_cmdline = 1;
1464 if (options.num_ports >= MAX_PORTS) {
1465 fprintf(stderr, "too many ports.\n");
1466 exit(1);
1467 }
1468 options.ports[options.num_ports++] = a2port(optarg);
1469 if (options.ports[options.num_ports-1] <= 0) {
1470 fprintf(stderr, "Bad port number.\n");
1471 exit(1);
1472 }
1473 break;
1474 case 'g':
1475 if ((options.login_grace_time = convtime(optarg)) == -1) {
1476 fprintf(stderr, "Invalid login grace time.\n");
1477 exit(1);
1478 }
1479 break;
1480 case 'k':
1481 /* protocol 1, ignored */
1482 break;
1483 case 'h':
1484 if (options.num_host_key_files >= MAX_HOSTKEYS) {
1485 fprintf(stderr, "too many host keys.\n");
1486 exit(1);
1487 }
1488 options.host_key_files[options.num_host_key_files++] =
1489 derelativise_path(optarg);
1490 break;
1491 case 't':
1492 test_flag = 1;
1493 break;
1494 case 'T':
1495 test_flag = 2;
1496 break;
1497 case 'C':
1498 if (parse_server_match_testspec(connection_info,
1499 optarg) == -1)
1500 exit(1);
1501 break;
1502 case 'u':
1503 utmp_len = (u_int)strtonum(optarg, 0, HOST_NAME_MAX+1+1, NULL);
1504 if (utmp_len > HOST_NAME_MAX+1) {
1505 fprintf(stderr, "Invalid utmp length.\n");
1506 exit(1);
1507 }
1508 break;
1509 case 'o':
1510 line = xstrdup(optarg);
1511 if (process_server_config_line(&options, line,
1512 "command-line", 0, NULL, NULL) != 0)
1513 exit(1);
1514 free(line);
1515 break;
1516 case '?':
1517 default:
1518 usage();
1519 break;
1520 }
1521 }
1522 if (rexeced_flag || inetd_flag)
1523 rexec_flag = 0;
1524 if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/')))
1525 fatal("sshd re-exec requires execution with an absolute path");
1526 if (rexeced_flag)
1527 closefrom(REEXEC_MIN_FREE_FD);
1528 else
1529 closefrom(REEXEC_DEVCRYPTO_RESERVED_FD);
1530
1531 #ifdef WITH_OPENSSL
1532 OpenSSL_add_all_algorithms();
1533 #endif
1534
1535 /* If requested, redirect the logs to the specified logfile. */
1536 if (logfile != NULL)
1537 log_redirect_stderr_to(logfile);
1538 /*
1539 * Force logging to stderr until we have loaded the private host
1540 * key (unless started from inetd)
1541 */
1542 log_init(__progname,
1543 options.log_level == SYSLOG_LEVEL_NOT_SET ?
1544 SYSLOG_LEVEL_INFO : options.log_level,
1545 options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1546 SYSLOG_FACILITY_AUTH : options.log_facility,
1547 log_stderr || !inetd_flag);
1548
1549 /*
1550 * Unset KRB5CCNAME, otherwise the user's session may inherit it from
1551 * root's environment
1552 */
1553 if (getenv("KRB5CCNAME") != NULL)
1554 (void) unsetenv("KRB5CCNAME");
1555
1556 #ifdef _UNICOS
1557 /* Cray can define user privs drop all privs now!
1558 * Not needed on PRIV_SU systems!
1559 */
1560 drop_cray_privs();
1561 #endif
1562
1563 sensitive_data.have_ssh2_key = 0;
1564
1565 /*
1566 * If we're doing an extended config test, make sure we have all of
1567 * the parameters we need. If we're not doing an extended test,
1568 * do not silently ignore connection test params.
1569 */
1570 if (test_flag >= 2 && server_match_spec_complete(connection_info) == 0)
1571 fatal("user, host and addr are all required when testing "
1572 "Match configs");
1573 if (test_flag < 2 && server_match_spec_complete(connection_info) >= 0)
1574 fatal("Config test connection parameter (-C) provided without "
1575 "test mode (-T)");
1576
1577 /* Fetch our configuration */
1578 buffer_init(&cfg);
1579 if (rexeced_flag)
1580 recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg);
1581 else if (strcasecmp(config_file_name, "none") != 0)
1582 load_server_config(config_file_name, &cfg);
1583
1584 parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name,
1585 &cfg, NULL);
1586
1587 seed_rng();
1588
1589 /* Fill in default values for those options not explicitly set. */
1590 fill_default_server_options(&options);
1591
1592 /* challenge-response is implemented via keyboard interactive */
1593 if (options.challenge_response_authentication)
1594 options.kbd_interactive_authentication = 1;
1595
1596 /* Check that options are sensible */
1597 if (options.authorized_keys_command_user == NULL &&
1598 (options.authorized_keys_command != NULL &&
1599 strcasecmp(options.authorized_keys_command, "none") != 0))
1600 fatal("AuthorizedKeysCommand set without "
1601 "AuthorizedKeysCommandUser");
1602 if (options.authorized_principals_command_user == NULL &&
1603 (options.authorized_principals_command != NULL &&
1604 strcasecmp(options.authorized_principals_command, "none") != 0))
1605 fatal("AuthorizedPrincipalsCommand set without "
1606 "AuthorizedPrincipalsCommandUser");
1607
1608 /*
1609 * Check whether there is any path through configured auth methods.
1610 * Unfortunately it is not possible to verify this generally before
1611 * daemonisation in the presence of Match block, but this catches
1612 * and warns for trivial misconfigurations that could break login.
1613 */
1614 if (options.num_auth_methods != 0) {
1615 for (n = 0; n < options.num_auth_methods; n++) {
1616 if (auth2_methods_valid(options.auth_methods[n],
1617 1) == 0)
1618 break;
1619 }
1620 if (n >= options.num_auth_methods)
1621 fatal("AuthenticationMethods cannot be satisfied by "
1622 "enabled authentication methods");
1623 }
1624
1625 /* set default channel AF */
1626 channel_set_af(options.address_family);
1627
1628 /* Check that there are no remaining arguments. */
1629 if (optind < ac) {
1630 fprintf(stderr, "Extra argument %s.\n", av[optind]);
1631 exit(1);
1632 }
1633
1634 debug("sshd version %s, %s", SSH_VERSION,
1635 #ifdef WITH_OPENSSL
1636 SSLeay_version(SSLEAY_VERSION)
1637 #else
1638 "without OpenSSL"
1639 #endif
1640 );
1641
1642 /* Store privilege separation user for later use if required. */
1643 if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) {
1644 if (use_privsep || options.kerberos_authentication)
1645 fatal("Privilege separation user %s does not exist",
1646 SSH_PRIVSEP_USER);
1647 } else {
1648 #if defined(ANDROID)
1649 /* Android does not do passwords and passes NULL for them. This breaks strlen */
1650 if (privsep_pw->pw_passwd) {
1651 #endif
1652 explicit_bzero(privsep_pw->pw_passwd,
1653 strlen(privsep_pw->pw_passwd));
1654 privsep_pw = pwcopy(privsep_pw);
1655 free(privsep_pw->pw_passwd);
1656 #if defined(ANDROID)
1657 }
1658 #endif
1659 privsep_pw->pw_passwd = xstrdup("*");
1660 }
1661 #if !defined(ANDROID)
1662 endpwent();
1663 #endif
1664
1665 /* load host keys */
1666 sensitive_data.host_keys = xcalloc(options.num_host_key_files,
1667 sizeof(Key *));
1668 sensitive_data.host_pubkeys = xcalloc(options.num_host_key_files,
1669 sizeof(Key *));
1670
1671 if (options.host_key_agent) {
1672 if (strcmp(options.host_key_agent, SSH_AUTHSOCKET_ENV_NAME))
1673 setenv(SSH_AUTHSOCKET_ENV_NAME,
1674 options.host_key_agent, 1);
1675 if ((r = ssh_get_authentication_socket(NULL)) == 0)
1676 have_agent = 1;
1677 else
1678 error("Could not connect to agent \"%s\": %s",
1679 options.host_key_agent, ssh_err(r));
1680 }
1681
1682 for (i = 0; i < options.num_host_key_files; i++) {
1683 if (options.host_key_files[i] == NULL)
1684 continue;
1685 key = key_load_private(options.host_key_files[i], "", NULL);
1686 pubkey = key_load_public(options.host_key_files[i], NULL);
1687
1688 if ((pubkey != NULL && pubkey->type == KEY_RSA1) ||
1689 (key != NULL && key->type == KEY_RSA1)) {
1690 verbose("Ignoring RSA1 key %s",
1691 options.host_key_files[i]);
1692 key_free(key);
1693 key_free(pubkey);
1694 continue;
1695 }
1696 if (pubkey == NULL && key != NULL)
1697 pubkey = key_demote(key);
1698 sensitive_data.host_keys[i] = key;
1699 sensitive_data.host_pubkeys[i] = pubkey;
1700
1701 if (key == NULL && pubkey != NULL && have_agent) {
1702 debug("will rely on agent for hostkey %s",
1703 options.host_key_files[i]);
1704 keytype = pubkey->type;
1705 } else if (key != NULL) {
1706 keytype = key->type;
1707 } else {
1708 error("Could not load host key: %s",
1709 options.host_key_files[i]);
1710 sensitive_data.host_keys[i] = NULL;
1711 sensitive_data.host_pubkeys[i] = NULL;
1712 continue;
1713 }
1714
1715 switch (keytype) {
1716 case KEY_RSA:
1717 case KEY_DSA:
1718 case KEY_ECDSA:
1719 case KEY_ED25519:
1720 if (have_agent || key != NULL)
1721 sensitive_data.have_ssh2_key = 1;
1722 break;
1723 }
1724 if ((fp = sshkey_fingerprint(pubkey, options.fingerprint_hash,
1725 SSH_FP_DEFAULT)) == NULL)
1726 fatal("sshkey_fingerprint failed");
1727 debug("%s host key #%d: %s %s",
1728 key ? "private" : "agent", i, sshkey_ssh_name(pubkey), fp);
1729 free(fp);
1730 }
1731 if (!sensitive_data.have_ssh2_key) {
1732 logit("sshd: no hostkeys available -- exiting.");
1733 exit(1);
1734 }
1735
1736 /*
1737 * Load certificates. They are stored in an array at identical
1738 * indices to the public keys that they relate to.
1739 */
1740 sensitive_data.host_certificates = xcalloc(options.num_host_key_files,
1741 sizeof(Key *));
1742 for (i = 0; i < options.num_host_key_files; i++)
1743 sensitive_data.host_certificates[i] = NULL;
1744
1745 for (i = 0; i < options.num_host_cert_files; i++) {
1746 if (options.host_cert_files[i] == NULL)
1747 continue;
1748 key = key_load_public(options.host_cert_files[i], NULL);
1749 if (key == NULL) {
1750 error("Could not load host certificate: %s",
1751 options.host_cert_files[i]);
1752 continue;
1753 }
1754 if (!key_is_cert(key)) {
1755 error("Certificate file is not a certificate: %s",
1756 options.host_cert_files[i]);
1757 key_free(key);
1758 continue;
1759 }
1760 /* Find matching private key */
1761 for (j = 0; j < options.num_host_key_files; j++) {
1762 if (key_equal_public(key,
1763 sensitive_data.host_keys[j])) {
1764 sensitive_data.host_certificates[j] = key;
1765 break;
1766 }
1767 }
1768 if (j >= options.num_host_key_files) {
1769 error("No matching private key for certificate: %s",
1770 options.host_cert_files[i]);
1771 key_free(key);
1772 continue;
1773 }
1774 sensitive_data.host_certificates[j] = key;
1775 debug("host certificate: #%d type %d %s", j, key->type,
1776 key_type(key));
1777 }
1778
1779 if (use_privsep) {
1780 struct stat st;
1781
1782 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
1783 (S_ISDIR(st.st_mode) == 0))
1784 fatal("Missing privilege separation directory: %s",
1785 _PATH_PRIVSEP_CHROOT_DIR);
1786
1787 #ifdef HAVE_CYGWIN
1788 if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) &&
1789 (st.st_uid != getuid () ||
1790 (st.st_mode & (S_IWGRP|S_IWOTH)) != 0))
1791 #else
1792 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
1793 #endif
1794 fatal("%s must be owned by root and not group or "
1795 "world-writable.", _PATH_PRIVSEP_CHROOT_DIR);
1796 }
1797
1798 if (test_flag > 1) {
1799 if (server_match_spec_complete(connection_info) == 1)
1800 parse_server_match_config(&options, connection_info);
1801 dump_config(&options);
1802 }
1803
1804 /* Configuration looks good, so exit if in test mode. */
1805 if (test_flag)
1806 exit(0);
1807
1808 /*
1809 * Clear out any supplemental groups we may have inherited. This
1810 * prevents inadvertent creation of files with bad modes (in the
1811 * portable version at least, it's certainly possible for PAM
1812 * to create a file, and we can't control the code in every
1813 * module which might be used).
1814 */
1815 if (setgroups(0, NULL) < 0)
1816 debug("setgroups() failed: %.200s", strerror(errno));
1817
1818 if (rexec_flag) {
1819 rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *));
1820 for (i = 0; i < rexec_argc; i++) {
1821 debug("rexec_argv[%d]='%s'", i, saved_argv[i]);
1822 rexec_argv[i] = saved_argv[i];
1823 }
1824 rexec_argv[rexec_argc] = "-R";
1825 rexec_argv[rexec_argc + 1] = NULL;
1826 }
1827
1828 /* Ensure that umask disallows at least group and world write */
1829 new_umask = umask(0077) | 0022;
1830 (void) umask(new_umask);
1831
1832 /* Initialize the log (it is reinitialized below in case we forked). */
1833 if (debug_flag && (!inetd_flag || rexeced_flag))
1834 log_stderr = 1;
1835 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1836
1837 /*
1838 * If not in debugging mode, not started from inetd and not already
1839 * daemonized (eg re-exec via SIGHUP), disconnect from the controlling
1840 * terminal, and fork. The original process exits.
1841 */
1842 already_daemon = daemonized();
1843 if (!(debug_flag || inetd_flag || no_daemon_flag || already_daemon)) {
1844
1845 if (daemon(0, 0) < 0)
1846 fatal("daemon() failed: %.200s", strerror(errno));
1847
1848 disconnect_controlling_tty();
1849 }
1850 /* Reinitialize the log (because of the fork above). */
1851 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1852
1853 /* Chdir to the root directory so that the current disk can be
1854 unmounted if desired. */
1855 if (chdir("/") == -1)
1856 error("chdir(\"/\"): %s", strerror(errno));
1857
1858 /* ignore SIGPIPE */
1859 signal(SIGPIPE, SIG_IGN);
1860
1861 /* Get a connection, either from inetd or a listening TCP socket */
1862 if (inetd_flag) {
1863 server_accept_inetd(&sock_in, &sock_out);
1864 } else {
1865 platform_pre_listen();
1866 server_listen();
1867
1868 signal(SIGHUP, sighup_handler);
1869 signal(SIGCHLD, main_sigchld_handler);
1870 signal(SIGTERM, sigterm_handler);
1871 signal(SIGQUIT, sigterm_handler);
1872
1873 /*
1874 * Write out the pid file after the sigterm handler
1875 * is setup and the listen sockets are bound
1876 */
1877 if (options.pid_file != NULL && !debug_flag) {
1878 FILE *f = fopen(options.pid_file, "w");
1879
1880 if (f == NULL) {
1881 error("Couldn't create pid file \"%s\": %s",
1882 options.pid_file, strerror(errno));
1883 } else {
1884 fprintf(f, "%ld\n", (long) getpid());
1885 fclose(f);
1886 }
1887 }
1888
1889 /* Accept a connection and return in a forked child */
1890 server_accept_loop(&sock_in, &sock_out,
1891 &newsock, config_s);
1892 }
1893
1894 /* This is the child processing a new connection. */
1895 setproctitle("%s", "[accepted]");
1896
1897 /*
1898 * Create a new session and process group since the 4.4BSD
1899 * setlogin() affects the entire process group. We don't
1900 * want the child to be able to affect the parent.
1901 */
1902 #if !defined(SSHD_ACQUIRES_CTTY)
1903 /*
1904 * If setsid is called, on some platforms sshd will later acquire a
1905 * controlling terminal which will result in "could not set
1906 * controlling tty" errors.
1907 */
1908 if (!debug_flag && !inetd_flag && setsid() < 0)
1909 error("setsid: %.100s", strerror(errno));
1910 #endif
1911
1912 if (rexec_flag) {
1913 int fd;
1914
1915 debug("rexec start in %d out %d newsock %d pipe %d sock %d",
1916 sock_in, sock_out, newsock, startup_pipe, config_s[0]);
1917 dup2(newsock, STDIN_FILENO);
1918 dup2(STDIN_FILENO, STDOUT_FILENO);
1919 if (startup_pipe == -1)
1920 close(REEXEC_STARTUP_PIPE_FD);
1921 else if (startup_pipe != REEXEC_STARTUP_PIPE_FD) {
1922 dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD);
1923 close(startup_pipe);
1924 startup_pipe = REEXEC_STARTUP_PIPE_FD;
1925 }
1926
1927 dup2(config_s[1], REEXEC_CONFIG_PASS_FD);
1928 close(config_s[1]);
1929
1930 execv(rexec_argv[0], rexec_argv);
1931
1932 /* Reexec has failed, fall back and continue */
1933 error("rexec of %s failed: %s", rexec_argv[0], strerror(errno));
1934 recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL);
1935 log_init(__progname, options.log_level,
1936 options.log_facility, log_stderr);
1937
1938 /* Clean up fds */
1939 close(REEXEC_CONFIG_PASS_FD);
1940 newsock = sock_out = sock_in = dup(STDIN_FILENO);
1941 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1942 dup2(fd, STDIN_FILENO);
1943 dup2(fd, STDOUT_FILENO);
1944 if (fd > STDERR_FILENO)
1945 close(fd);
1946 }
1947 debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d",
1948 sock_in, sock_out, newsock, startup_pipe, config_s[0]);
1949 }
1950
1951 /* Executed child processes don't need these. */
1952 fcntl(sock_out, F_SETFD, FD_CLOEXEC);
1953 fcntl(sock_in, F_SETFD, FD_CLOEXEC);
1954
1955 /*
1956 * Disable the key regeneration alarm. We will not regenerate the
1957 * key since we are no longer in a position to give it to anyone. We
1958 * will not restart on SIGHUP since it no longer makes sense.
1959 */
1960 alarm(0);
1961 signal(SIGALRM, SIG_DFL);
1962 signal(SIGHUP, SIG_DFL);
1963 signal(SIGTERM, SIG_DFL);
1964 signal(SIGQUIT, SIG_DFL);
1965 signal(SIGCHLD, SIG_DFL);
1966 signal(SIGINT, SIG_DFL);
1967
1968 /*
1969 * Register our connection. This turns encryption off because we do
1970 * not have a key.
1971 */
1972 packet_set_connection(sock_in, sock_out);
1973 packet_set_server();
1974 ssh = active_state; /* XXX */
1975 check_ip_options(ssh);
1976
1977 /* Set SO_KEEPALIVE if requested. */
1978 if (options.tcp_keep_alive && packet_connection_is_on_socket() &&
1979 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0)
1980 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1981
1982 if ((remote_port = ssh_remote_port(ssh)) < 0) {
1983 debug("ssh_remote_port failed");
1984 cleanup_exit(255);
1985 }
1986
1987 /*
1988 * The rest of the code depends on the fact that
1989 * ssh_remote_ipaddr() caches the remote ip, even if
1990 * the socket goes away.
1991 */
1992 remote_ip = ssh_remote_ipaddr(ssh);
1993
1994 #ifdef SSH_AUDIT_EVENTS
1995 audit_connection_from(remote_ip, remote_port);
1996 #endif
1997
1998 /* Log the connection. */
1999 laddr = get_local_ipaddr(sock_in);
2000 verbose("Connection from %s port %d on %s port %d",
2001 remote_ip, remote_port, laddr, ssh_local_port(ssh));
2002 free(laddr);
2003
2004 /*
2005 * We don't want to listen forever unless the other side
2006 * successfully authenticates itself. So we set up an alarm which is
2007 * cleared after successful authentication. A limit of zero
2008 * indicates no limit. Note that we don't set the alarm in debugging
2009 * mode; it is just annoying to have the server exit just when you
2010 * are about to discover the bug.
2011 */
2012 signal(SIGALRM, grace_alarm_handler);
2013 if (!debug_flag)
2014 alarm(options.login_grace_time);
2015
2016 sshd_exchange_identification(ssh, sock_in, sock_out);
2017 packet_set_nonblocking();
2018
2019 /* allocate authentication context */
2020 authctxt = xcalloc(1, sizeof(*authctxt));
2021
2022 authctxt->loginmsg = &loginmsg;
2023
2024 /* XXX global for cleanup, access from other modules */
2025 the_authctxt = authctxt;
2026
2027 /* prepare buffer to collect messages to display to user after login */
2028 buffer_init(&loginmsg);
2029 auth_debug_reset();
2030
2031 if (use_privsep) {
2032 if (privsep_preauth(authctxt) == 1)
2033 goto authenticated;
2034 } else if (have_agent) {
2035 if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) {
2036 error("Unable to get agent socket: %s", ssh_err(r));
2037 have_agent = 0;
2038 }
2039 }
2040
2041 /* perform the key exchange */
2042 /* authenticate user and start session */
2043 do_ssh2_kex();
2044 do_authentication2(authctxt);
2045
2046 /*
2047 * If we use privilege separation, the unprivileged child transfers
2048 * the current keystate and exits
2049 */
2050 if (use_privsep) {
2051 mm_send_keystate(pmonitor);
2052 exit(0);
2053 }
2054
2055 authenticated:
2056 /*
2057 * Cancel the alarm we set to limit the time taken for
2058 * authentication.
2059 */
2060 alarm(0);
2061 signal(SIGALRM, SIG_DFL);
2062 authctxt->authenticated = 1;
2063 if (startup_pipe != -1) {
2064 close(startup_pipe);
2065 startup_pipe = -1;
2066 }
2067
2068 #ifdef SSH_AUDIT_EVENTS
2069 audit_event(SSH_AUTH_SUCCESS);
2070 #endif
2071
2072 #ifdef GSSAPI
2073 if (options.gss_authentication) {
2074 temporarily_use_uid(authctxt->pw);
2075 ssh_gssapi_storecreds();
2076 restore_uid();
2077 }
2078 #endif
2079 #ifdef USE_PAM
2080 if (options.use_pam) {
2081 do_pam_setcred(1);
2082 do_pam_session();
2083 }
2084 #endif
2085
2086 /*
2087 * In privilege separation, we fork another child and prepare
2088 * file descriptor passing.
2089 */
2090 if (use_privsep) {
2091 privsep_postauth(authctxt);
2092 /* the monitor process [priv] will not return */
2093 }
2094
2095 packet_set_timeout(options.client_alive_interval,
2096 options.client_alive_count_max);
2097
2098 /* Try to send all our hostkeys to the client */
2099 notify_hostkeys(active_state);
2100
2101 /* Start session. */
2102 do_authenticated(authctxt);
2103
2104 /* The connection has been terminated. */
2105 packet_get_bytes(&ibytes, &obytes);
2106 verbose("Transferred: sent %llu, received %llu bytes",
2107 (unsigned long long)obytes, (unsigned long long)ibytes);
2108
2109 verbose("Closing connection to %.500s port %d", remote_ip, remote_port);
2110
2111 #ifdef USE_PAM
2112 if (options.use_pam)
2113 finish_pam();
2114 #endif /* USE_PAM */
2115
2116 #ifdef SSH_AUDIT_EVENTS
2117 PRIVSEP(audit_event(SSH_CONNECTION_CLOSE));
2118 #endif
2119
2120 packet_close();
2121
2122 if (use_privsep)
2123 mm_terminate();
2124
2125 exit(0);
2126 }
2127
2128 int
2129 sshd_hostkey_sign(Key *privkey, Key *pubkey, u_char **signature, size_t *slen,
2130 const u_char *data, size_t dlen, const char *alg, u_int flag)
2131 {
2132 int r;
2133 u_int xxx_slen, xxx_dlen = dlen;
2134
2135 if (privkey) {
2136 if (PRIVSEP(key_sign(privkey, signature, &xxx_slen, data, xxx_dlen,
2137 alg) < 0))
2138 fatal("%s: key_sign failed", __func__);
2139 if (slen)
2140 *slen = xxx_slen;
2141 } else if (use_privsep) {
2142 if (mm_key_sign(pubkey, signature, &xxx_slen, data, xxx_dlen,
2143 alg) < 0)
2144 fatal("%s: pubkey_sign failed", __func__);
2145 if (slen)
2146 *slen = xxx_slen;
2147 } else {
2148 if ((r = ssh_agent_sign(auth_sock, pubkey, signature, slen,
2149 data, dlen, alg, datafellows)) != 0)
2150 fatal("%s: ssh_agent_sign failed: %s",
2151 __func__, ssh_err(r));
2152 }
2153 return 0;
2154 }
2155
2156 /* SSH2 key exchange */
2157 static void
2158 do_ssh2_kex(void)
2159 {
2160 char *myproposal[PROPOSAL_MAX] = { KEX_SERVER };
2161 struct kex *kex;
2162 int r;
2163
2164 myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(
2165 options.kex_algorithms);
2166 myproposal[PROPOSAL_ENC_ALGS_CTOS] = compat_cipher_proposal(
2167 options.ciphers);
2168 myproposal[PROPOSAL_ENC_ALGS_STOC] = compat_cipher_proposal(
2169 options.ciphers);
2170 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
2171 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
2172
2173 if (options.compression == COMP_NONE) {
2174 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
2175 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
2176 }
2177
2178 if (options.rekey_limit || options.rekey_interval)
2179 packet_set_rekey_limits(options.rekey_limit,
2180 options.rekey_interval);
2181
2182 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal(
2183 list_hostkey_types());
2184
2185 /* start key exchange */
2186 if ((r = kex_setup(active_state, myproposal)) != 0)
2187 fatal("kex_setup: %s", ssh_err(r));
2188 kex = active_state->kex;
2189 #ifdef WITH_OPENSSL
2190 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
2191 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
2192 kex->kex[KEX_DH_GRP14_SHA256] = kexdh_server;
2193 kex->kex[KEX_DH_GRP16_SHA512] = kexdh_server;
2194 kex->kex[KEX_DH_GRP18_SHA512] = kexdh_server;
2195 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
2196 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
2197 # ifdef OPENSSL_HAS_ECC
2198 kex->kex[KEX_ECDH_SHA2] = kexecdh_server;
2199 # endif
2200 #endif
2201 kex->kex[KEX_C25519_SHA256] = kexc25519_server;
2202 kex->server = 1;
2203 kex->client_version_string=client_version_string;
2204 kex->server_version_string=server_version_string;
2205 kex->load_host_public_key=&get_hostkey_public_by_type;
2206 kex->load_host_private_key=&get_hostkey_private_by_type;
2207 kex->host_key_index=&get_hostkey_index;
2208 kex->sign = sshd_hostkey_sign;
2209
2210 dispatch_run(DISPATCH_BLOCK, &kex->done, active_state);
2211
2212 session_id2 = kex->session_id;
2213 session_id2_len = kex->session_id_len;
2214
2215 #ifdef DEBUG_KEXDH
2216 /* send 1st encrypted/maced/compressed message */
2217 packet_start(SSH2_MSG_IGNORE);
2218 packet_put_cstring("markus");
2219 packet_send();
2220 packet_write_wait();
2221 #endif
2222 debug("KEX done");
2223 }
2224
2225 /* server specific fatal cleanup */
2226 void
2227 cleanup_exit(int i)
2228 {
2229 if (the_authctxt) {
2230 do_cleanup(the_authctxt);
2231 if (use_privsep && privsep_is_preauth &&
2232 pmonitor != NULL && pmonitor->m_pid > 1) {
2233 debug("Killing privsep child %d", pmonitor->m_pid);
2234 if (kill(pmonitor->m_pid, SIGKILL) != 0 &&
2235 errno != ESRCH)
2236 error("%s: kill(%d): %s", __func__,
2237 pmonitor->m_pid, strerror(errno));
2238 }
2239 }
2240 #ifdef SSH_AUDIT_EVENTS
2241 /* done after do_cleanup so it can cancel the PAM auth 'thread' */
2242 if (!use_privsep || mm_is_monitor())
2243 audit_event(SSH_CONNECTION_ABANDON);
2244 #endif
2245 _exit(i);
2246 }
2247