1 /* $OpenBSD: sshd-session.c,v 1.12 2025/03/12 22:43:44 djm Exp $ */
2 /*
3 * SSH2 implementation:
4 * Privilege Separation:
5 *
6 * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved.
7 * Copyright (c) 2002 Niels Provos. All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30 #include "includes.h"
31
32 #include <sys/types.h>
33 #include <sys/ioctl.h>
34 #include <sys/socket.h>
35 #ifdef HAVE_SYS_STAT_H
36 # include <sys/stat.h>
37 #endif
38 #ifdef HAVE_SYS_TIME_H
39 # include <sys/time.h>
40 #endif
41 #include "openbsd-compat/sys-tree.h"
42 #include "openbsd-compat/sys-queue.h"
43 #include <sys/wait.h>
44
45 #include <errno.h>
46 #include <fcntl.h>
47 #include <netdb.h>
48 #ifdef HAVE_PATHS_H
49 # include <paths.h>
50 #endif
51 #include <pwd.h>
52 #include <grp.h>
53 #include <signal.h>
54 #include <stdio.h>
55 #include <stdlib.h>
56 #include <string.h>
57 #include <stdarg.h>
58 #include <unistd.h>
59 #include <limits.h>
60
61 #ifdef WITH_OPENSSL
62 #include <openssl/bn.h>
63 #include <openssl/evp.h>
64 #include <openssl/rand.h>
65 #include "openbsd-compat/openssl-compat.h"
66 #endif
67
68 #ifdef HAVE_SECUREWARE
69 #include <sys/security.h>
70 #include <prot.h>
71 #endif
72
73 #include "xmalloc.h"
74 #include "ssh.h"
75 #include "ssh2.h"
76 #include "sshpty.h"
77 #include "packet.h"
78 #include "log.h"
79 #include "sshbuf.h"
80 #include "misc.h"
81 #include "match.h"
82 #include "servconf.h"
83 #include "uidswap.h"
84 #include "compat.h"
85 #include "cipher.h"
86 #include "digest.h"
87 #include "sshkey.h"
88 #include "kex.h"
89 #include "authfile.h"
90 #include "pathnames.h"
91 #include "atomicio.h"
92 #include "canohost.h"
93 #include "hostfile.h"
94 #include "auth.h"
95 #include "authfd.h"
96 #include "msg.h"
97 #include "dispatch.h"
98 #include "channels.h"
99 #include "session.h"
100 #include "monitor.h"
101 #ifdef GSSAPI
102 #include "ssh-gss.h"
103 #endif
104 #include "monitor_wrap.h"
105 #include "auth-options.h"
106 #include "version.h"
107 #include "ssherr.h"
108 #include "sk-api.h"
109 #include "srclimit.h"
110 #include "dh.h"
111 #include "blacklist_client.h"
112
113 /* Re-exec fds */
114 #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1)
115 #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 2)
116 #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 3)
117
118 /* Privsep fds */
119 #define PRIVSEP_MONITOR_FD (STDERR_FILENO + 1)
120 #define PRIVSEP_LOG_FD (STDERR_FILENO + 2)
121 #define PRIVSEP_MIN_FREE_FD (STDERR_FILENO + 3)
122
123 extern char *__progname;
124
125 /* Server configuration options. */
126 ServerOptions options;
127
128 /* Name of the server configuration file. */
129 char *config_file_name = _PATH_SERVER_CONFIG_FILE;
130
131 /*
132 * Debug mode flag. This can be set on the command line. If debug
133 * mode is enabled, extra debugging output will be sent to the system
134 * log, the daemon will not go to background, and will exit after processing
135 * the first connection.
136 */
137 int debug_flag = 0;
138
139 /* Flag indicating that the daemon is being started from inetd. */
140 static int inetd_flag = 0;
141
142 /* debug goes to stderr unless inetd_flag is set */
143 static int log_stderr = 0;
144
145 /* Saved arguments to main(). */
146 static char **saved_argv;
147 static int saved_argc;
148
149 /* Daemon's agent connection */
150 int auth_sock = -1;
151 static int have_agent = 0;
152
153 /*
154 * Any really sensitive data in the application is contained in this
155 * structure. The idea is that this structure could be locked into memory so
156 * that the pages do not get written into swap. However, there are some
157 * problems. The private key contains BIGNUMs, and we do not (in principle)
158 * have access to the internals of them, and locking just the structure is
159 * not very useful. Currently, memory locking is not implemented.
160 */
161 struct {
162 u_int num_hostkeys;
163 struct sshkey **host_keys; /* all private host keys */
164 struct sshkey **host_pubkeys; /* all public host keys */
165 struct sshkey **host_certificates; /* all public host certificates */
166 } sensitive_data;
167
168 /* record remote hostname or ip */
169 u_int utmp_len = HOST_NAME_MAX+1;
170
171 static int startup_pipe = -1; /* in child */
172
173 /* variables used for privilege separation */
174 struct monitor *pmonitor = NULL;
175 int privsep_is_preauth = 1;
176 static int privsep_chroot = 1;
177
178 /* Unprivileged user */
179 struct passwd *privsep_pw = NULL;
180
181 /* global connection state and authentication contexts */
182 Authctxt *the_authctxt = NULL;
183 struct ssh *the_active_state;
184
185 /* global key/cert auth options. XXX move to permanent ssh->authctxt? */
186 struct sshauthopt *auth_opts = NULL;
187
188 /* sshd_config buffer */
189 struct sshbuf *cfg;
190
191 /* Included files from the configuration file */
192 struct include_list includes = TAILQ_HEAD_INITIALIZER(includes);
193
194 /* message to be displayed after login */
195 struct sshbuf *loginmsg;
196
197 /* Prototypes for various functions defined later in this file. */
198 void destroy_sensitive_data(void);
199 void demote_sensitive_data(void);
200
201 /* XXX reduce to stub once postauth split */
202 int
mm_is_monitor(void)203 mm_is_monitor(void)
204 {
205 /*
206 * m_pid is only set in the privileged part, and
207 * points to the unprivileged child.
208 */
209 return (pmonitor && pmonitor->m_pid > 0);
210 }
211
212 /*
213 * Signal handler for the alarm after the login grace period has expired.
214 * As usual, this may only take signal-safe actions, even though it is
215 * terminal.
216 */
217 static void
grace_alarm_handler(int sig)218 grace_alarm_handler(int sig)
219 {
220 /*
221 * Try to kill any processes that we have spawned, E.g. authorized
222 * keys command helpers or privsep children.
223 */
224 if (getpgid(0) == getpid()) {
225 struct sigaction sa;
226
227 /* mask all other signals while in handler */
228 memset(&sa, 0, sizeof(sa));
229 sa.sa_handler = SIG_IGN;
230 sigfillset(&sa.sa_mask);
231 #if defined(SA_RESTART)
232 sa.sa_flags = SA_RESTART;
233 #endif
234 (void)sigaction(SIGTERM, &sa, NULL);
235 kill(0, SIGTERM);
236 }
237 _exit(EXIT_LOGIN_GRACE);
238 }
239
240 /* Destroy the host and server keys. They will no longer be needed. */
241 void
destroy_sensitive_data(void)242 destroy_sensitive_data(void)
243 {
244 u_int i;
245
246 for (i = 0; i < options.num_host_key_files; i++) {
247 if (sensitive_data.host_keys[i]) {
248 sshkey_free(sensitive_data.host_keys[i]);
249 sensitive_data.host_keys[i] = NULL;
250 }
251 if (sensitive_data.host_certificates[i]) {
252 sshkey_free(sensitive_data.host_certificates[i]);
253 sensitive_data.host_certificates[i] = NULL;
254 }
255 }
256 }
257
258 /* Demote private to public keys for network child */
259 void
demote_sensitive_data(void)260 demote_sensitive_data(void)
261 {
262 struct sshkey *tmp;
263 u_int i;
264 int r;
265
266 for (i = 0; i < options.num_host_key_files; i++) {
267 if (sensitive_data.host_keys[i]) {
268 if ((r = sshkey_from_private(
269 sensitive_data.host_keys[i], &tmp)) != 0)
270 fatal_r(r, "could not demote host %s key",
271 sshkey_type(sensitive_data.host_keys[i]));
272 sshkey_free(sensitive_data.host_keys[i]);
273 sensitive_data.host_keys[i] = tmp;
274 }
275 /* Certs do not need demotion */
276 }
277 }
278
279 static void
reseed_prngs(void)280 reseed_prngs(void)
281 {
282 u_int32_t rnd[256];
283
284 #ifdef WITH_OPENSSL
285 RAND_poll();
286 #endif
287 arc4random_stir(); /* noop on recent arc4random() implementations */
288 arc4random_buf(rnd, sizeof(rnd)); /* let arc4random notice PID change */
289
290 #ifdef WITH_OPENSSL
291 RAND_seed(rnd, sizeof(rnd));
292 /* give libcrypto a chance to notice the PID change */
293 if ((RAND_bytes((u_char *)rnd, 1)) != 1)
294 fatal("%s: RAND_bytes failed", __func__);
295 #endif
296
297 explicit_bzero(rnd, sizeof(rnd));
298 }
299
300 struct sshbuf *
pack_hostkeys(void)301 pack_hostkeys(void)
302 {
303 struct sshbuf *keybuf = NULL, *hostkeys = NULL;
304 int r;
305 u_int i;
306
307 if ((hostkeys = sshbuf_new()) == NULL)
308 fatal_f("sshbuf_new failed");
309
310 /* pack hostkeys into a string. Empty key slots get empty strings */
311 for (i = 0; i < options.num_host_key_files; i++) {
312 /* public key */
313 if (sensitive_data.host_pubkeys[i] != NULL) {
314 if ((r = sshkey_puts(sensitive_data.host_pubkeys[i],
315 hostkeys)) != 0)
316 fatal_fr(r, "compose hostkey public");
317 } else {
318 if ((r = sshbuf_put_string(hostkeys, NULL, 0)) != 0)
319 fatal_fr(r, "compose hostkey empty public");
320 }
321 /* cert */
322 if (sensitive_data.host_certificates[i] != NULL) {
323 if ((r = sshkey_puts(
324 sensitive_data.host_certificates[i],
325 hostkeys)) != 0)
326 fatal_fr(r, "compose host cert");
327 } else {
328 if ((r = sshbuf_put_string(hostkeys, NULL, 0)) != 0)
329 fatal_fr(r, "compose host cert empty");
330 }
331 }
332
333 sshbuf_free(keybuf);
334 return hostkeys;
335 }
336
337 static int
privsep_preauth(struct ssh * ssh)338 privsep_preauth(struct ssh *ssh)
339 {
340 int status, r;
341 pid_t pid;
342
343 /* Set up unprivileged child process to deal with network data */
344 pmonitor = monitor_init();
345 /* Store a pointer to the kex for later rekeying */
346 pmonitor->m_pkex = &ssh->kex;
347
348 if ((pid = fork()) == -1)
349 fatal("fork of unprivileged child failed");
350 else if (pid != 0) {
351 debug2("Network child is on pid %ld", (long)pid);
352
353 pmonitor->m_pid = pid;
354 if (have_agent) {
355 r = ssh_get_authentication_socket(&auth_sock);
356 if (r != 0) {
357 error_r(r, "Could not get agent socket");
358 have_agent = 0;
359 }
360 }
361 monitor_child_preauth(ssh, pmonitor);
362
363 /* Wait for the child's exit status */
364 while (waitpid(pid, &status, 0) == -1) {
365 if (errno == EINTR)
366 continue;
367 pmonitor->m_pid = -1;
368 fatal_f("waitpid: %s", strerror(errno));
369 }
370 privsep_is_preauth = 0;
371 pmonitor->m_pid = -1;
372 if (WIFEXITED(status)) {
373 if (WEXITSTATUS(status) != 0)
374 fatal_f("preauth child exited with status %d",
375 WEXITSTATUS(status));
376 } else if (WIFSIGNALED(status))
377 fatal_f("preauth child terminated by signal %d",
378 WTERMSIG(status));
379 return 1;
380 } else {
381 /* child */
382 close(pmonitor->m_sendfd);
383 close(pmonitor->m_log_recvfd);
384
385 /*
386 * Arrange unpriv-preauth child process fds:
387 * 0, 1 network socket
388 * 2 optional stderr
389 * 3 reserved
390 * 4 monitor message socket
391 * 5 monitor logging socket
392 *
393 * We know that the monitor sockets will have fds > 4 because
394 * of the reserved fds in main()
395 */
396
397 if (ssh_packet_get_connection_in(ssh) != STDIN_FILENO &&
398 dup2(ssh_packet_get_connection_in(ssh), STDIN_FILENO) == -1)
399 fatal("dup2 stdin failed: %s", strerror(errno));
400 if (ssh_packet_get_connection_out(ssh) != STDOUT_FILENO &&
401 dup2(ssh_packet_get_connection_out(ssh),
402 STDOUT_FILENO) == -1)
403 fatal("dup2 stdout failed: %s", strerror(errno));
404 /* leave stderr as-is */
405 log_redirect_stderr_to(NULL); /* dup can clobber log fd */
406 if (pmonitor->m_recvfd != PRIVSEP_MONITOR_FD &&
407 dup2(pmonitor->m_recvfd, PRIVSEP_MONITOR_FD) == -1)
408 fatal("dup2 monitor fd: %s", strerror(errno));
409 if (pmonitor->m_log_sendfd != PRIVSEP_LOG_FD &&
410 dup2(pmonitor->m_log_sendfd, PRIVSEP_LOG_FD) == -1)
411 fatal("dup2 log fd: %s", strerror(errno));
412 closefrom(PRIVSEP_MIN_FREE_FD);
413
414 saved_argv[0] = options.sshd_auth_path;
415 execv(options.sshd_auth_path, saved_argv);
416
417 fatal_f("exec of %s failed: %s",
418 options.sshd_auth_path, strerror(errno));
419 }
420 }
421
422 static void
privsep_postauth(struct ssh * ssh,Authctxt * authctxt)423 privsep_postauth(struct ssh *ssh, Authctxt *authctxt)
424 {
425 int skip_privdrop = 0;
426
427 /*
428 * Hack for systems that don't support FD passing: retain privileges
429 * in the post-auth privsep process so it can allocate PTYs directly.
430 * This is basically equivalent to what we did <= 9.7, which was to
431 * disable post-auth privsep entriely.
432 * Cygwin doesn't need to drop privs here although it doesn't support
433 * fd passing, as AFAIK PTY allocation on this platform doesn't require
434 * special privileges to begin with.
435 */
436 #if defined(DISABLE_FD_PASSING) && !defined(HAVE_CYGWIN)
437 skip_privdrop = 1;
438 #endif
439
440 /* New socket pair */
441 monitor_reinit(pmonitor);
442
443 pmonitor->m_pid = fork();
444 if (pmonitor->m_pid == -1)
445 fatal("fork of unprivileged child failed");
446 else if (pmonitor->m_pid != 0) {
447 verbose("User child is on pid %ld", (long)pmonitor->m_pid);
448 sshbuf_reset(loginmsg);
449 monitor_clear_keystate(ssh, pmonitor);
450 monitor_child_postauth(ssh, pmonitor);
451
452 /* NEVERREACHED */
453 exit(0);
454 }
455
456 /* child */
457
458 close(pmonitor->m_sendfd);
459 pmonitor->m_sendfd = -1;
460
461 /* Demote the private keys to public keys. */
462 demote_sensitive_data();
463
464 reseed_prngs();
465
466 /* Drop privileges */
467 if (!skip_privdrop)
468 do_setusercontext(authctxt->pw);
469
470 /* It is safe now to apply the key state */
471 monitor_apply_keystate(ssh, pmonitor);
472
473 /*
474 * Tell the packet layer that authentication was successful, since
475 * this information is not part of the key state.
476 */
477 ssh_packet_set_authenticated(ssh);
478 }
479
480 static struct sshkey *
get_hostkey_by_type(int type,int nid,int need_private,struct ssh * ssh)481 get_hostkey_by_type(int type, int nid, int need_private, struct ssh *ssh)
482 {
483 u_int i;
484 struct sshkey *key;
485
486 for (i = 0; i < options.num_host_key_files; i++) {
487 switch (type) {
488 case KEY_RSA_CERT:
489 case KEY_DSA_CERT:
490 case KEY_ECDSA_CERT:
491 case KEY_ED25519_CERT:
492 case KEY_ECDSA_SK_CERT:
493 case KEY_ED25519_SK_CERT:
494 case KEY_XMSS_CERT:
495 key = sensitive_data.host_certificates[i];
496 break;
497 default:
498 key = sensitive_data.host_keys[i];
499 if (key == NULL && !need_private)
500 key = sensitive_data.host_pubkeys[i];
501 break;
502 }
503 if (key == NULL || key->type != type)
504 continue;
505 switch (type) {
506 case KEY_ECDSA:
507 case KEY_ECDSA_SK:
508 case KEY_ECDSA_CERT:
509 case KEY_ECDSA_SK_CERT:
510 if (key->ecdsa_nid != nid)
511 continue;
512 /* FALLTHROUGH */
513 default:
514 return need_private ?
515 sensitive_data.host_keys[i] : key;
516 }
517 }
518 return NULL;
519 }
520
521 struct sshkey *
get_hostkey_public_by_type(int type,int nid,struct ssh * ssh)522 get_hostkey_public_by_type(int type, int nid, struct ssh *ssh)
523 {
524 return get_hostkey_by_type(type, nid, 0, ssh);
525 }
526
527 struct sshkey *
get_hostkey_private_by_type(int type,int nid,struct ssh * ssh)528 get_hostkey_private_by_type(int type, int nid, struct ssh *ssh)
529 {
530 return get_hostkey_by_type(type, nid, 1, ssh);
531 }
532
533 struct sshkey *
get_hostkey_by_index(int ind)534 get_hostkey_by_index(int ind)
535 {
536 if (ind < 0 || (u_int)ind >= options.num_host_key_files)
537 return (NULL);
538 return (sensitive_data.host_keys[ind]);
539 }
540
541 struct sshkey *
get_hostkey_public_by_index(int ind,struct ssh * ssh)542 get_hostkey_public_by_index(int ind, struct ssh *ssh)
543 {
544 if (ind < 0 || (u_int)ind >= options.num_host_key_files)
545 return (NULL);
546 return (sensitive_data.host_pubkeys[ind]);
547 }
548
549 int
get_hostkey_index(struct sshkey * key,int compare,struct ssh * ssh)550 get_hostkey_index(struct sshkey *key, int compare, struct ssh *ssh)
551 {
552 u_int i;
553
554 for (i = 0; i < options.num_host_key_files; i++) {
555 if (sshkey_is_cert(key)) {
556 if (key == sensitive_data.host_certificates[i] ||
557 (compare && sensitive_data.host_certificates[i] &&
558 sshkey_equal(key,
559 sensitive_data.host_certificates[i])))
560 return (i);
561 } else {
562 if (key == sensitive_data.host_keys[i] ||
563 (compare && sensitive_data.host_keys[i] &&
564 sshkey_equal(key, sensitive_data.host_keys[i])))
565 return (i);
566 if (key == sensitive_data.host_pubkeys[i] ||
567 (compare && sensitive_data.host_pubkeys[i] &&
568 sshkey_equal(key, sensitive_data.host_pubkeys[i])))
569 return (i);
570 }
571 }
572 return (-1);
573 }
574
575 /* Inform the client of all hostkeys */
576 static void
notify_hostkeys(struct ssh * ssh)577 notify_hostkeys(struct ssh *ssh)
578 {
579 struct sshbuf *buf;
580 struct sshkey *key;
581 u_int i, nkeys;
582 int r;
583 char *fp;
584
585 /* Some clients cannot cope with the hostkeys message, skip those. */
586 if (ssh->compat & SSH_BUG_HOSTKEYS)
587 return;
588
589 if ((buf = sshbuf_new()) == NULL)
590 fatal_f("sshbuf_new");
591 for (i = nkeys = 0; i < options.num_host_key_files; i++) {
592 key = get_hostkey_public_by_index(i, ssh);
593 if (key == NULL || key->type == KEY_UNSPEC ||
594 sshkey_is_cert(key))
595 continue;
596 fp = sshkey_fingerprint(key, options.fingerprint_hash,
597 SSH_FP_DEFAULT);
598 debug3_f("key %d: %s %s", i, sshkey_ssh_name(key), fp);
599 free(fp);
600 if (nkeys == 0) {
601 /*
602 * Start building the request when we find the
603 * first usable key.
604 */
605 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
606 (r = sshpkt_put_cstring(ssh, "hostkeys-00@openssh.com")) != 0 ||
607 (r = sshpkt_put_u8(ssh, 0)) != 0) /* want reply */
608 sshpkt_fatal(ssh, r, "%s: start request", __func__);
609 }
610 /* Append the key to the request */
611 sshbuf_reset(buf);
612 if ((r = sshkey_putb(key, buf)) != 0)
613 fatal_fr(r, "couldn't put hostkey %d", i);
614 if ((r = sshpkt_put_stringb(ssh, buf)) != 0)
615 sshpkt_fatal(ssh, r, "%s: append key", __func__);
616 nkeys++;
617 }
618 debug3_f("sent %u hostkeys", nkeys);
619 if (nkeys == 0)
620 fatal_f("no hostkeys");
621 if ((r = sshpkt_send(ssh)) != 0)
622 sshpkt_fatal(ssh, r, "%s: send", __func__);
623 sshbuf_free(buf);
624 }
625
626 static void
usage(void)627 usage(void)
628 {
629 fprintf(stderr, "%s, %s\n", SSH_RELEASE, SSH_OPENSSL_VERSION);
630 fprintf(stderr,
631 "usage: sshd [-46DdeGiqTtV] [-C connection_spec] [-c host_cert_file]\n"
632 " [-E log_file] [-f config_file] [-g login_grace_time]\n"
633 " [-h host_key_file] [-o option] [-p port] [-u len]\n"
634 );
635 exit(1);
636 }
637
638 static void
parse_hostkeys(struct sshbuf * hostkeys)639 parse_hostkeys(struct sshbuf *hostkeys)
640 {
641 int r;
642 u_int num_keys = 0;
643 struct sshkey *k;
644 struct sshbuf *kbuf;
645 const u_char *cp;
646 size_t len;
647
648 while (sshbuf_len(hostkeys) != 0) {
649 if (num_keys > 2048)
650 fatal_f("too many hostkeys");
651 sensitive_data.host_keys = xrecallocarray(
652 sensitive_data.host_keys, num_keys, num_keys + 1,
653 sizeof(*sensitive_data.host_pubkeys));
654 sensitive_data.host_pubkeys = xrecallocarray(
655 sensitive_data.host_pubkeys, num_keys, num_keys + 1,
656 sizeof(*sensitive_data.host_pubkeys));
657 sensitive_data.host_certificates = xrecallocarray(
658 sensitive_data.host_certificates, num_keys, num_keys + 1,
659 sizeof(*sensitive_data.host_certificates));
660 /* private key */
661 k = NULL;
662 if ((r = sshbuf_froms(hostkeys, &kbuf)) != 0)
663 fatal_fr(r, "extract privkey");
664 if (sshbuf_len(kbuf) != 0 &&
665 (r = sshkey_private_deserialize(kbuf, &k)) != 0)
666 fatal_fr(r, "parse pubkey");
667 sensitive_data.host_keys[num_keys] = k;
668 sshbuf_free(kbuf);
669 if (k)
670 debug2_f("privkey %u: %s", num_keys, sshkey_ssh_name(k));
671 /* public key */
672 k = NULL;
673 if ((r = sshbuf_get_string_direct(hostkeys, &cp, &len)) != 0)
674 fatal_fr(r, "extract pubkey");
675 if (len != 0 && (r = sshkey_from_blob(cp, len, &k)) != 0)
676 fatal_fr(r, "parse pubkey");
677 sensitive_data.host_pubkeys[num_keys] = k;
678 if (k)
679 debug2_f("pubkey %u: %s", num_keys, sshkey_ssh_name(k));
680 /* certificate */
681 k = NULL;
682 if ((r = sshbuf_get_string_direct(hostkeys, &cp, &len)) != 0)
683 fatal_fr(r, "extract pubkey");
684 if (len != 0 && (r = sshkey_from_blob(cp, len, &k)) != 0)
685 fatal_fr(r, "parse pubkey");
686 sensitive_data.host_certificates[num_keys] = k;
687 if (k)
688 debug2_f("cert %u: %s", num_keys, sshkey_ssh_name(k));
689 num_keys++;
690 }
691 sensitive_data.num_hostkeys = num_keys;
692 }
693
694 static void
recv_rexec_state(int fd,struct sshbuf * conf,uint64_t * timing_secretp)695 recv_rexec_state(int fd, struct sshbuf *conf, uint64_t *timing_secretp)
696 {
697 struct sshbuf *m, *inc, *hostkeys;
698 u_char *cp, ver;
699 size_t len;
700 int r;
701 struct include_item *item;
702
703 debug3_f("entering fd = %d", fd);
704
705 if ((m = sshbuf_new()) == NULL || (inc = sshbuf_new()) == NULL)
706 fatal_f("sshbuf_new failed");
707
708 /* receive config */
709 if (ssh_msg_recv(fd, m) == -1)
710 fatal_f("ssh_msg_recv failed");
711 if ((r = sshbuf_get_u8(m, &ver)) != 0)
712 fatal_fr(r, "parse version");
713 if (ver != 0)
714 fatal_f("rexec version mismatch");
715 if ((r = sshbuf_get_string(m, &cp, &len)) != 0 || /* XXX _direct */
716 (r = sshbuf_get_u64(m, timing_secretp)) != 0 ||
717 (r = sshbuf_get_stringb(m, inc)) != 0)
718 fatal_fr(r, "parse config");
719
720 if (conf != NULL && (r = sshbuf_put(conf, cp, len)))
721 fatal_fr(r, "sshbuf_put");
722
723 while (sshbuf_len(inc) != 0) {
724 item = xcalloc(1, sizeof(*item));
725 if ((item->contents = sshbuf_new()) == NULL)
726 fatal_f("sshbuf_new failed");
727 if ((r = sshbuf_get_cstring(inc, &item->selector, NULL)) != 0 ||
728 (r = sshbuf_get_cstring(inc, &item->filename, NULL)) != 0 ||
729 (r = sshbuf_get_stringb(inc, item->contents)) != 0)
730 fatal_fr(r, "parse includes");
731 TAILQ_INSERT_TAIL(&includes, item, entry);
732 }
733
734 /* receive hostkeys */
735 sshbuf_reset(m);
736 if (ssh_msg_recv(fd, m) == -1)
737 fatal_f("ssh_msg_recv failed");
738 if ((r = sshbuf_get_u8(m, NULL)) != 0 ||
739 (r = sshbuf_froms(m, &hostkeys)) != 0)
740 fatal_fr(r, "parse config");
741 parse_hostkeys(hostkeys);
742
743 free(cp);
744 sshbuf_free(m);
745 sshbuf_free(hostkeys);
746 sshbuf_free(inc);
747
748 debug3_f("done");
749 }
750
751 /*
752 * If IP options are supported, make sure there are none (log and
753 * return an error if any are found). Basically we are worried about
754 * source routing; it can be used to pretend you are somebody
755 * (ip-address) you are not. That itself may be "almost acceptable"
756 * under certain circumstances, but rhosts authentication is useless
757 * if source routing is accepted. Notice also that if we just dropped
758 * source routing here, the other side could use IP spoofing to do
759 * rest of the interaction and could still bypass security. So we
760 * exit here if we detect any IP options.
761 */
762 static void
check_ip_options(struct ssh * ssh)763 check_ip_options(struct ssh *ssh)
764 {
765 #ifdef IP_OPTIONS
766 int sock_in = ssh_packet_get_connection_in(ssh);
767 struct sockaddr_storage from;
768 u_char opts[200];
769 socklen_t i, option_size = sizeof(opts), fromlen = sizeof(from);
770 char text[sizeof(opts) * 3 + 1];
771
772 memset(&from, 0, sizeof(from));
773 if (getpeername(sock_in, (struct sockaddr *)&from,
774 &fromlen) == -1)
775 return;
776 if (from.ss_family != AF_INET)
777 return;
778 /* XXX IPv6 options? */
779
780 if (getsockopt(sock_in, IPPROTO_IP, IP_OPTIONS, opts,
781 &option_size) >= 0 && option_size != 0) {
782 text[0] = '\0';
783 for (i = 0; i < option_size; i++)
784 snprintf(text + i*3, sizeof(text) - i*3,
785 " %2.2x", opts[i]);
786 fatal("Connection from %.100s port %d with IP opts: %.800s",
787 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), text);
788 }
789 #endif /* IP_OPTIONS */
790 }
791
792 /* Set the routing domain for this process */
793 static void
set_process_rdomain(struct ssh * ssh,const char * name)794 set_process_rdomain(struct ssh *ssh, const char *name)
795 {
796 #if defined(HAVE_SYS_SET_PROCESS_RDOMAIN)
797 if (name == NULL)
798 return; /* default */
799
800 if (strcmp(name, "%D") == 0) {
801 /* "expands" to routing domain of connection */
802 if ((name = ssh_packet_rdomain_in(ssh)) == NULL)
803 return;
804 }
805 /* NB. We don't pass 'ssh' to sys_set_process_rdomain() */
806 return sys_set_process_rdomain(name);
807 #elif defined(__OpenBSD__)
808 int rtable, ortable = getrtable();
809 const char *errstr;
810
811 if (name == NULL)
812 return; /* default */
813
814 if (strcmp(name, "%D") == 0) {
815 /* "expands" to routing domain of connection */
816 if ((name = ssh_packet_rdomain_in(ssh)) == NULL)
817 return;
818 }
819
820 rtable = (int)strtonum(name, 0, 255, &errstr);
821 if (errstr != NULL) /* Shouldn't happen */
822 fatal("Invalid routing domain \"%s\": %s", name, errstr);
823 if (rtable != ortable && setrtable(rtable) != 0)
824 fatal("Unable to set routing domain %d: %s",
825 rtable, strerror(errno));
826 debug_f("set routing domain %d (was %d)", rtable, ortable);
827 #else /* defined(__OpenBSD__) */
828 fatal("Unable to set routing domain: not supported in this platform");
829 #endif
830 }
831
832 /*
833 * Main program for the daemon.
834 */
835 int
main(int ac,char ** av)836 main(int ac, char **av)
837 {
838 struct ssh *ssh = NULL;
839 extern char *optarg;
840 extern int optind;
841 int devnull, r, opt, on = 1, remote_port;
842 int sock_in = -1, sock_out = -1, rexeced_flag = 0, have_key = 0;
843 const char *remote_ip, *rdomain;
844 char *line, *laddr, *logfile = NULL;
845 u_int i;
846 u_int64_t ibytes, obytes;
847 mode_t new_umask;
848 Authctxt *authctxt;
849 struct connection_info *connection_info = NULL;
850 sigset_t sigmask;
851 uint64_t timing_secret = 0;
852 struct itimerval itv;
853
854 sigemptyset(&sigmask);
855 sigprocmask(SIG_SETMASK, &sigmask, NULL);
856
857 #ifdef HAVE_SECUREWARE
858 (void)set_auth_parameters(ac, av);
859 #endif
860 __progname = ssh_get_progname(av[0]);
861
862 /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */
863 saved_argc = ac;
864 saved_argv = xcalloc(ac + 1, sizeof(*saved_argv));
865 for (i = 0; (int)i < ac; i++)
866 saved_argv[i] = xstrdup(av[i]);
867 saved_argv[i] = NULL;
868
869 #ifndef HAVE_SETPROCTITLE
870 /* Prepare for later setproctitle emulation */
871 compat_init_setproctitle(ac, av);
872 av = saved_argv;
873 #endif
874
875 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
876 sanitise_stdfd();
877
878 /* Initialize configuration options to their default values. */
879 initialize_server_options(&options);
880
881 /* Parse command-line arguments. */
882 while ((opt = getopt(ac, av,
883 "C:E:b:c:f:g:h:k:o:p:u:46DGQRTdeiqrtV")) != -1) {
884 switch (opt) {
885 case '4':
886 options.address_family = AF_INET;
887 break;
888 case '6':
889 options.address_family = AF_INET6;
890 break;
891 case 'f':
892 config_file_name = optarg;
893 break;
894 case 'c':
895 servconf_add_hostcert("[command-line]", 0,
896 &options, optarg);
897 break;
898 case 'd':
899 if (debug_flag == 0) {
900 debug_flag = 1;
901 options.log_level = SYSLOG_LEVEL_DEBUG1;
902 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
903 options.log_level++;
904 break;
905 case 'D':
906 /* ignore */
907 break;
908 case 'E':
909 logfile = optarg;
910 /* FALLTHROUGH */
911 case 'e':
912 log_stderr = 1;
913 break;
914 case 'i':
915 inetd_flag = 1;
916 break;
917 case 'r':
918 /* ignore */
919 break;
920 case 'R':
921 rexeced_flag = 1;
922 break;
923 case 'Q':
924 /* ignored */
925 break;
926 case 'q':
927 options.log_level = SYSLOG_LEVEL_QUIET;
928 break;
929 case 'b':
930 /* protocol 1, ignored */
931 break;
932 case 'p':
933 options.ports_from_cmdline = 1;
934 if (options.num_ports >= MAX_PORTS) {
935 fprintf(stderr, "too many ports.\n");
936 exit(1);
937 }
938 options.ports[options.num_ports++] = a2port(optarg);
939 if (options.ports[options.num_ports-1] <= 0) {
940 fprintf(stderr, "Bad port number.\n");
941 exit(1);
942 }
943 break;
944 case 'g':
945 if ((options.login_grace_time = convtime(optarg)) == -1) {
946 fprintf(stderr, "Invalid login grace time.\n");
947 exit(1);
948 }
949 break;
950 case 'k':
951 /* protocol 1, ignored */
952 break;
953 case 'h':
954 servconf_add_hostkey("[command-line]", 0,
955 &options, optarg, 1);
956 break;
957 case 't':
958 case 'T':
959 case 'G':
960 fatal("test/dump modes not supported");
961 break;
962 case 'C':
963 connection_info = server_get_connection_info(ssh, 0, 0);
964 if (parse_server_match_testspec(connection_info,
965 optarg) == -1)
966 exit(1);
967 break;
968 case 'u':
969 utmp_len = (u_int)strtonum(optarg, 0, HOST_NAME_MAX+1+1, NULL);
970 if (utmp_len > HOST_NAME_MAX+1) {
971 fprintf(stderr, "Invalid utmp length.\n");
972 exit(1);
973 }
974 break;
975 case 'o':
976 line = xstrdup(optarg);
977 if (process_server_config_line(&options, line,
978 "command-line", 0, NULL, NULL, &includes) != 0)
979 exit(1);
980 free(line);
981 break;
982 case 'V':
983 fprintf(stderr, "%s, %s\n",
984 SSH_RELEASE, SSH_OPENSSL_VERSION);
985 exit(0);
986 default:
987 usage();
988 break;
989 }
990 }
991
992 /* Check that there are no remaining arguments. */
993 if (optind < ac) {
994 fprintf(stderr, "Extra argument %s.\n", av[optind]);
995 exit(1);
996 }
997
998 if (!rexeced_flag)
999 fatal("sshd-session should not be executed directly");
1000
1001 closefrom(REEXEC_MIN_FREE_FD);
1002
1003 platform_pre_session_start();
1004
1005 /* Reserve fds we'll need later for reexec things */
1006 if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1)
1007 fatal("open %s: %s", _PATH_DEVNULL, strerror(errno));
1008 while (devnull < PRIVSEP_MIN_FREE_FD) {
1009 if ((devnull = dup(devnull)) == -1)
1010 fatal("dup %s: %s", _PATH_DEVNULL, strerror(errno));
1011 }
1012
1013 seed_rng();
1014
1015 /* If requested, redirect the logs to the specified logfile. */
1016 if (logfile != NULL) {
1017 char *cp, pid_s[32];
1018
1019 snprintf(pid_s, sizeof(pid_s), "%ld", (unsigned long)getpid());
1020 cp = percent_expand(logfile,
1021 "p", pid_s,
1022 "P", "sshd-session",
1023 (char *)NULL);
1024 log_redirect_stderr_to(cp);
1025 free(cp);
1026 }
1027
1028 /*
1029 * Force logging to stderr until we have loaded the private host
1030 * key (unless started from inetd)
1031 */
1032 log_init(__progname,
1033 options.log_level == SYSLOG_LEVEL_NOT_SET ?
1034 SYSLOG_LEVEL_INFO : options.log_level,
1035 options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1036 SYSLOG_FACILITY_AUTH : options.log_facility,
1037 log_stderr || !inetd_flag || debug_flag);
1038
1039 /* Fetch our configuration */
1040 if ((cfg = sshbuf_new()) == NULL)
1041 fatal("sshbuf_new config buf failed");
1042 setproctitle("%s", "[rexeced]");
1043 recv_rexec_state(REEXEC_CONFIG_PASS_FD, cfg, &timing_secret);
1044 parse_server_config(&options, "rexec", cfg, &includes, NULL, 1);
1045 /* Fill in default values for those options not explicitly set. */
1046 fill_default_server_options(&options);
1047 options.timing_secret = timing_secret;
1048
1049 /* Reinit logging in case config set Level, Facility or Verbose. */
1050 log_init(__progname, options.log_level, options.log_facility,
1051 log_stderr || !inetd_flag || debug_flag);
1052
1053 debug("sshd-session version %s, %s", SSH_VERSION, SSH_OPENSSL_VERSION);
1054
1055 /* Store privilege separation user for later use if required. */
1056 privsep_chroot = (getuid() == 0 || geteuid() == 0);
1057 if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) {
1058 if (privsep_chroot || options.kerberos_authentication)
1059 fatal("Privilege separation user %s does not exist",
1060 SSH_PRIVSEP_USER);
1061 } else {
1062 privsep_pw = pwcopy(privsep_pw);
1063 freezero(privsep_pw->pw_passwd, strlen(privsep_pw->pw_passwd));
1064 privsep_pw->pw_passwd = xstrdup("*");
1065 }
1066 endpwent();
1067
1068 if (!debug_flag && !inetd_flag) {
1069 if ((startup_pipe = dup(REEXEC_CONFIG_PASS_FD)) == -1)
1070 fatal("internal error: no startup pipe");
1071
1072 /*
1073 * Signal parent that this child is at a point where
1074 * they can go away if they have a SIGHUP pending.
1075 */
1076 (void)atomicio(vwrite, startup_pipe, "\0", 1);
1077 }
1078 /* close the fd, but keep the slot reserved */
1079 if (dup2(devnull, REEXEC_CONFIG_PASS_FD) == -1)
1080 fatal("dup2 devnull->config fd: %s", strerror(errno));
1081
1082 /* Check that options are sensible */
1083 if (options.authorized_keys_command_user == NULL &&
1084 (options.authorized_keys_command != NULL &&
1085 strcasecmp(options.authorized_keys_command, "none") != 0))
1086 fatal("AuthorizedKeysCommand set without "
1087 "AuthorizedKeysCommandUser");
1088 if (options.authorized_principals_command_user == NULL &&
1089 (options.authorized_principals_command != NULL &&
1090 strcasecmp(options.authorized_principals_command, "none") != 0))
1091 fatal("AuthorizedPrincipalsCommand set without "
1092 "AuthorizedPrincipalsCommandUser");
1093
1094 /*
1095 * Check whether there is any path through configured auth methods.
1096 * Unfortunately it is not possible to verify this generally before
1097 * daemonisation in the presence of Match block, but this catches
1098 * and warns for trivial misconfigurations that could break login.
1099 */
1100 if (options.num_auth_methods != 0) {
1101 for (i = 0; i < options.num_auth_methods; i++) {
1102 if (auth2_methods_valid(options.auth_methods[i],
1103 1) == 0)
1104 break;
1105 }
1106 if (i >= options.num_auth_methods)
1107 fatal("AuthenticationMethods cannot be satisfied by "
1108 "enabled authentication methods");
1109 }
1110
1111 #ifdef WITH_OPENSSL
1112 if (options.moduli_file != NULL)
1113 dh_set_moduli_file(options.moduli_file);
1114 #endif
1115
1116 if (options.host_key_agent) {
1117 if (strcmp(options.host_key_agent, SSH_AUTHSOCKET_ENV_NAME))
1118 setenv(SSH_AUTHSOCKET_ENV_NAME,
1119 options.host_key_agent, 1);
1120 if ((r = ssh_get_authentication_socket(NULL)) == 0)
1121 have_agent = 1;
1122 else
1123 error_r(r, "Could not connect to agent \"%s\"",
1124 options.host_key_agent);
1125 }
1126
1127 if (options.num_host_key_files != sensitive_data.num_hostkeys) {
1128 fatal("internal error: hostkeys confused (config %u recvd %u)",
1129 options.num_host_key_files, sensitive_data.num_hostkeys);
1130 }
1131
1132 for (i = 0; i < options.num_host_key_files; i++) {
1133 if (sensitive_data.host_keys[i] != NULL ||
1134 (have_agent && sensitive_data.host_pubkeys[i] != NULL)) {
1135 have_key = 1;
1136 break;
1137 }
1138 }
1139 if (!have_key)
1140 fatal("internal error: monitor received no hostkeys");
1141
1142 /* Ensure that umask disallows at least group and world write */
1143 new_umask = umask(0077) | 0022;
1144 (void) umask(new_umask);
1145
1146 /* Initialize the log (it is reinitialized below in case we forked). */
1147 if (debug_flag)
1148 log_stderr = 1;
1149 log_init(__progname, options.log_level,
1150 options.log_facility, log_stderr);
1151 for (i = 0; i < options.num_log_verbose; i++)
1152 log_verbose_add(options.log_verbose[i]);
1153
1154 /* Reinitialize the log (because of the fork above). */
1155 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1156
1157 /*
1158 * Chdir to the root directory so that the current disk can be
1159 * unmounted if desired.
1160 */
1161 if (chdir("/") == -1)
1162 error("chdir(\"/\"): %s", strerror(errno));
1163
1164 /* ignore SIGPIPE */
1165 ssh_signal(SIGPIPE, SIG_IGN);
1166
1167 /* Get a connection, either from inetd or rexec */
1168 if (inetd_flag) {
1169 /*
1170 * NB. must be different fd numbers for the !socket case,
1171 * as packet_connection_is_on_socket() depends on this.
1172 */
1173 sock_in = dup(STDIN_FILENO);
1174 sock_out = dup(STDOUT_FILENO);
1175 } else {
1176 /* rexec case; accept()ed socket in ancestor listener */
1177 sock_in = sock_out = dup(STDIN_FILENO);
1178 }
1179
1180 /*
1181 * We intentionally do not close the descriptors 0, 1, and 2
1182 * as our code for setting the descriptors won't work if
1183 * ttyfd happens to be one of those.
1184 */
1185 if (stdfd_devnull(1, 1, !log_stderr) == -1)
1186 error("stdfd_devnull failed");
1187 debug("network sockets: %d, %d", sock_in, sock_out);
1188
1189 /* This is the child processing a new connection. */
1190 setproctitle("%s", "[accepted]");
1191
1192 /* Executed child processes don't need these. */
1193 fcntl(sock_out, F_SETFD, FD_CLOEXEC);
1194 fcntl(sock_in, F_SETFD, FD_CLOEXEC);
1195
1196 /* We will not restart on SIGHUP since it no longer makes sense. */
1197 ssh_signal(SIGALRM, SIG_DFL);
1198 ssh_signal(SIGHUP, SIG_DFL);
1199 ssh_signal(SIGTERM, SIG_DFL);
1200 ssh_signal(SIGQUIT, SIG_DFL);
1201 ssh_signal(SIGCHLD, SIG_DFL);
1202 ssh_signal(SIGINT, SIG_DFL);
1203
1204 /*
1205 * Register our connection. This turns encryption off because we do
1206 * not have a key.
1207 */
1208 if ((ssh = ssh_packet_set_connection(NULL, sock_in, sock_out)) == NULL)
1209 fatal("Unable to create connection");
1210 the_active_state = ssh;
1211 ssh_packet_set_server(ssh);
1212
1213 check_ip_options(ssh);
1214
1215 /* Prepare the channels layer */
1216 channel_init_channels(ssh);
1217 channel_set_af(ssh, options.address_family);
1218 server_process_channel_timeouts(ssh);
1219 server_process_permitopen(ssh);
1220
1221 /* Set SO_KEEPALIVE if requested. */
1222 if (options.tcp_keep_alive && ssh_packet_connection_is_on_socket(ssh) &&
1223 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) == -1)
1224 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1225
1226 if ((remote_port = ssh_remote_port(ssh)) < 0) {
1227 debug("ssh_remote_port failed");
1228 cleanup_exit(255);
1229 }
1230
1231 #ifdef HAVE_LOGIN_CAP
1232 /* Also caches remote hostname for sandboxed child. */
1233 auth_get_canonical_hostname(ssh, options.use_dns);
1234 #endif
1235
1236 /*
1237 * The rest of the code depends on the fact that
1238 * ssh_remote_ipaddr() caches the remote ip, even if
1239 * the socket goes away.
1240 */
1241 remote_ip = ssh_remote_ipaddr(ssh);
1242
1243 #ifdef SSH_AUDIT_EVENTS
1244 audit_connection_from(remote_ip, remote_port);
1245 #endif
1246
1247 rdomain = ssh_packet_rdomain_in(ssh);
1248
1249 /* Log the connection. */
1250 laddr = get_local_ipaddr(sock_in);
1251 verbose("Connection from %s port %d on %s port %d%s%s%s",
1252 remote_ip, remote_port, laddr, ssh_local_port(ssh),
1253 rdomain == NULL ? "" : " rdomain \"",
1254 rdomain == NULL ? "" : rdomain,
1255 rdomain == NULL ? "" : "\"");
1256 free(laddr);
1257
1258 /*
1259 * We don't want to listen forever unless the other side
1260 * successfully authenticates itself. So we set up an alarm which is
1261 * cleared after successful authentication. A limit of zero
1262 * indicates no limit. Note that we don't set the alarm in debugging
1263 * mode; it is just annoying to have the server exit just when you
1264 * are about to discover the bug.
1265 */
1266 ssh_signal(SIGALRM, grace_alarm_handler);
1267 if (!debug_flag && options.login_grace_time > 0) {
1268 int ujitter = arc4random_uniform(4 * 1000000);
1269
1270 timerclear(&itv.it_interval);
1271 itv.it_value.tv_sec = options.login_grace_time;
1272 itv.it_value.tv_sec += ujitter / 1000000;
1273 itv.it_value.tv_usec = ujitter % 1000000;
1274
1275 if (setitimer(ITIMER_REAL, &itv, NULL) == -1)
1276 fatal("login grace time setitimer failed");
1277 }
1278
1279 if ((r = kex_exchange_identification(ssh, -1,
1280 options.version_addendum)) != 0)
1281 sshpkt_fatal(ssh, r, "banner exchange");
1282
1283 ssh_packet_set_nonblocking(ssh);
1284
1285 /* allocate authentication context */
1286 authctxt = xcalloc(1, sizeof(*authctxt));
1287 ssh->authctxt = authctxt;
1288
1289 /* XXX global for cleanup, access from other modules */
1290 the_authctxt = authctxt;
1291
1292 /* Set default key authentication options */
1293 if ((auth_opts = sshauthopt_new_with_keys_defaults()) == NULL)
1294 fatal("allocation failed");
1295
1296 /* prepare buffer to collect messages to display to user after login */
1297 if ((loginmsg = sshbuf_new()) == NULL)
1298 fatal("sshbuf_new loginmsg failed");
1299 auth_debug_reset();
1300
1301 BLACKLIST_INIT();
1302
1303 if (privsep_preauth(ssh) != 1)
1304 fatal("privsep_preauth failed");
1305
1306 /* Now user is authenticated */
1307
1308 /*
1309 * Cancel the alarm we set to limit the time taken for
1310 * authentication.
1311 */
1312 timerclear(&itv.it_interval);
1313 timerclear(&itv.it_value);
1314 if (setitimer(ITIMER_REAL, &itv, NULL) == -1)
1315 fatal("login grace time clear failed");
1316 ssh_signal(SIGALRM, SIG_DFL);
1317 authctxt->authenticated = 1;
1318 if (startup_pipe != -1) {
1319 /* signal listener that authentication completed successfully */
1320 (void)atomicio(vwrite, startup_pipe, "\001", 1);
1321 close(startup_pipe);
1322 startup_pipe = -1;
1323 }
1324
1325 if (options.routing_domain != NULL)
1326 set_process_rdomain(ssh, options.routing_domain);
1327
1328 #ifdef SSH_AUDIT_EVENTS
1329 audit_event(ssh, SSH_AUTH_SUCCESS);
1330 #endif
1331
1332 #ifdef GSSAPI
1333 if (options.gss_authentication) {
1334 temporarily_use_uid(authctxt->pw);
1335 ssh_gssapi_storecreds();
1336 restore_uid();
1337 }
1338 #endif
1339 #ifdef USE_PAM
1340 if (options.use_pam) {
1341 do_pam_setcred();
1342 do_pam_session(ssh);
1343 }
1344 #endif
1345
1346 /*
1347 * In privilege separation, we fork another child and prepare
1348 * file descriptor passing.
1349 */
1350 privsep_postauth(ssh, authctxt);
1351 /* the monitor process [priv] will not return */
1352
1353 ssh_packet_set_timeout(ssh, options.client_alive_interval,
1354 options.client_alive_count_max);
1355
1356 /* Try to send all our hostkeys to the client */
1357 notify_hostkeys(ssh);
1358
1359 /* Start session. */
1360 do_authenticated(ssh, authctxt);
1361
1362 /* The connection has been terminated. */
1363 ssh_packet_get_bytes(ssh, &ibytes, &obytes);
1364 verbose("Transferred: sent %llu, received %llu bytes",
1365 (unsigned long long)obytes, (unsigned long long)ibytes);
1366
1367 verbose("Closing connection to %.500s port %d", remote_ip, remote_port);
1368
1369 #ifdef USE_PAM
1370 if (options.use_pam)
1371 finish_pam();
1372 #endif /* USE_PAM */
1373
1374 #ifdef SSH_AUDIT_EVENTS
1375 mm_audit_event(ssh, SSH_CONNECTION_CLOSE);
1376 #endif
1377
1378 ssh_packet_close(ssh);
1379
1380 mm_terminate();
1381
1382 exit(0);
1383 }
1384
1385 int
sshd_hostkey_sign(struct ssh * ssh,struct sshkey * privkey,struct sshkey * pubkey,u_char ** signature,size_t * slenp,const u_char * data,size_t dlen,const char * alg)1386 sshd_hostkey_sign(struct ssh *ssh, struct sshkey *privkey,
1387 struct sshkey *pubkey, u_char **signature, size_t *slenp,
1388 const u_char *data, size_t dlen, const char *alg)
1389 {
1390 if (privkey) {
1391 if (mm_sshkey_sign(ssh, privkey, signature, slenp,
1392 data, dlen, alg, options.sk_provider, NULL,
1393 ssh->compat) < 0)
1394 fatal_f("privkey sign failed");
1395 } else {
1396 if (mm_sshkey_sign(ssh, pubkey, signature, slenp,
1397 data, dlen, alg, options.sk_provider, NULL,
1398 ssh->compat) < 0)
1399 fatal_f("pubkey sign failed");
1400 }
1401 return 0;
1402 }
1403
1404 /* server specific fatal cleanup */
1405 void
cleanup_exit(int i)1406 cleanup_exit(int i)
1407 {
1408 extern int auth_attempted; /* monitor.c */
1409
1410 if (the_active_state != NULL && the_authctxt != NULL) {
1411 do_cleanup(the_active_state, the_authctxt);
1412 if (privsep_is_preauth &&
1413 pmonitor != NULL && pmonitor->m_pid > 1) {
1414 debug("Killing privsep child %d", pmonitor->m_pid);
1415 if (kill(pmonitor->m_pid, SIGKILL) != 0 &&
1416 errno != ESRCH) {
1417 error_f("kill(%d): %s", pmonitor->m_pid,
1418 strerror(errno));
1419 }
1420 }
1421 }
1422 #ifdef SSH_AUDIT_EVENTS
1423 /* done after do_cleanup so it can cancel the PAM auth 'thread' */
1424 if (the_active_state != NULL && mm_is_monitor())
1425 audit_event(the_active_state, SSH_CONNECTION_ABANDON);
1426 #endif
1427 /* Override default fatal exit value when auth was attempted */
1428 if (i == 255 && auth_attempted)
1429 _exit(EXIT_AUTH_ATTEMPTED);
1430 _exit(i);
1431 }
1432