1 /* $OpenBSD: sshd-session.c,v 1.24 2026/06/14 03:59:34 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/wait.h>
35 #include <sys/tree.h>
36 #include <sys/stat.h>
37 #include <sys/socket.h>
38 #include <sys/time.h>
39 #include <sys/queue.h>
40
41 #include <errno.h>
42 #include <fcntl.h>
43 #include <netdb.h>
44 #include <paths.h>
45 #include <pwd.h>
46 #include <grp.h>
47 #include <signal.h>
48 #include <stdio.h>
49 #include <stdlib.h>
50 #include <string.h>
51 #include <stdarg.h>
52 #include <unistd.h>
53 #include <limits.h>
54
55 #ifdef HAVE_SECUREWARE
56 #include <sys/security.h>
57 #include <prot.h>
58 #endif
59
60 #include "xmalloc.h"
61 #include "ssh.h"
62 #include "ssh2.h"
63 #include "sshpty.h"
64 #include "packet.h"
65 #include "log.h"
66 #include "sshbuf.h"
67 #include "misc.h"
68 #include "match.h"
69 #include "servconf.h"
70 #include "uidswap.h"
71 #include "compat.h"
72 #include "cipher.h"
73 #include "digest.h"
74 #include "sshkey.h"
75 #include "kex.h"
76 #include "authfile.h"
77 #include "pathnames.h"
78 #include "atomicio.h"
79 #include "canohost.h"
80 #include "hostfile.h"
81 #include "auth.h"
82 #include "authfd.h"
83 #include "msg.h"
84 #include "dispatch.h"
85 #include "channels.h"
86 #include "session.h"
87 #include "monitor.h"
88 #ifdef GSSAPI
89 #include "ssh-gss.h"
90 #endif
91 #include "monitor_wrap.h"
92 #include "auth-options.h"
93 #include "version.h"
94 #include "ssherr.h"
95 #include "sk-api.h"
96 #include "srclimit.h"
97 #include "dh.h"
98 #include "blocklist_client.h"
99
100 /* Re-exec fds */
101 #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1)
102 #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 2)
103 #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 3)
104
105 /* Privsep fds */
106 #define PRIVSEP_MONITOR_FD (STDERR_FILENO + 1)
107 #define PRIVSEP_LOG_FD (STDERR_FILENO + 2)
108 #define PRIVSEP_MIN_FREE_FD (STDERR_FILENO + 3)
109
110 extern char *__progname;
111
112 /* Server configuration options. */
113 ServerOptions options;
114
115 /* Name of the server configuration file. */
116 char *config_file_name = _PATH_SERVER_CONFIG_FILE;
117
118 /*
119 * Debug mode flag. This can be set on the command line. If debug
120 * mode is enabled, extra debugging output will be sent to the system
121 * log, the daemon will not go to background, and will exit after processing
122 * the first connection.
123 */
124 int debug_flag = 0;
125
126 /* Flag indicating that the daemon is being started from inetd. */
127 static int inetd_flag = 0;
128
129 /* debug goes to stderr unless inetd_flag is set */
130 static int log_stderr = 0;
131
132 /* Saved arguments to main(). */
133 static char **saved_argv;
134 static int saved_argc;
135
136 /* Daemon's agent connection */
137 int auth_sock = -1;
138 static int have_agent = 0;
139
140 /*
141 * Any really sensitive data in the application is contained in this
142 * structure. The idea is that this structure could be locked into memory so
143 * that the pages do not get written into swap. However, there are some
144 * problems. The private key contains BIGNUMs, and we do not (in principle)
145 * have access to the internals of them, and locking just the structure is
146 * not very useful. Currently, memory locking is not implemented.
147 */
148 struct {
149 u_int num_hostkeys;
150 struct sshkey **host_keys; /* all private host keys */
151 struct sshkey **host_pubkeys; /* all public host keys */
152 struct sshkey **host_certificates; /* all public host certificates */
153 } sensitive_data;
154
155 /* record remote hostname or ip */
156 u_int utmp_len = HOST_NAME_MAX+1;
157
158 static int startup_pipe = -1; /* in child */
159
160 /* variables used for privilege separation */
161 struct monitor *pmonitor = NULL;
162 int privsep_is_preauth = 1;
163 static int privsep_chroot = 1;
164
165 /* Unprivileged user */
166 struct passwd *privsep_pw = NULL;
167
168 /* global connection state and authentication contexts */
169 Authctxt *the_authctxt = NULL;
170 struct ssh *the_active_state;
171
172 /* global key/cert auth options. XXX move to permanent ssh->authctxt? */
173 struct sshauthopt *auth_opts = NULL;
174
175 /* sshd_config buffer */
176 struct sshbuf *cfg;
177
178 /* Included files from the configuration file */
179 struct include_list includes = TAILQ_HEAD_INITIALIZER(includes);
180
181 /* message to be displayed after login */
182 struct sshbuf *loginmsg;
183
184 /* Prototypes for various functions defined later in this file. */
185 void destroy_sensitive_data(void);
186 void demote_sensitive_data(void);
187
188 /* XXX reduce to stub once postauth split */
189 int
mm_is_monitor(void)190 mm_is_monitor(void)
191 {
192 /*
193 * m_pid is only set in the privileged part, and
194 * points to the unprivileged child.
195 */
196 return (pmonitor && pmonitor->m_pid > 0);
197 }
198
199 /*
200 * Signal handler for the alarm after the login grace period has expired.
201 * As usual, this may only take signal-safe actions, even though it is
202 * terminal.
203 */
204 static void
grace_alarm_handler(int sig)205 grace_alarm_handler(int sig)
206 {
207 /*
208 * Try to kill any processes that we have spawned, E.g. authorized
209 * keys command helpers or privsep children.
210 */
211 if (getpgid(0) == getpid()) {
212 struct sigaction sa;
213
214 /* mask all other signals while in handler */
215 memset(&sa, 0, sizeof(sa));
216 sa.sa_handler = SIG_IGN;
217 sigfillset(&sa.sa_mask);
218 #if defined(SA_RESTART)
219 sa.sa_flags = SA_RESTART;
220 #endif
221 (void)sigaction(SIGTERM, &sa, NULL);
222 kill(0, SIGTERM);
223 }
224 _exit(EXIT_LOGIN_GRACE);
225 }
226
227 /* Destroy the host and server keys. They will no longer be needed. */
228 void
destroy_sensitive_data(void)229 destroy_sensitive_data(void)
230 {
231 u_int i;
232
233 for (i = 0; i < options.num_host_key_files; i++) {
234 if (sensitive_data.host_keys[i]) {
235 sshkey_free(sensitive_data.host_keys[i]);
236 sensitive_data.host_keys[i] = NULL;
237 }
238 if (sensitive_data.host_certificates[i]) {
239 sshkey_free(sensitive_data.host_certificates[i]);
240 sensitive_data.host_certificates[i] = NULL;
241 }
242 }
243 }
244
245 /* Demote private to public keys for network child */
246 void
demote_sensitive_data(void)247 demote_sensitive_data(void)
248 {
249 struct sshkey *tmp;
250 u_int i;
251 int r;
252
253 for (i = 0; i < options.num_host_key_files; i++) {
254 if (sensitive_data.host_keys[i]) {
255 if ((r = sshkey_from_private(
256 sensitive_data.host_keys[i], &tmp)) != 0)
257 fatal_r(r, "could not demote host %s key",
258 sshkey_type(sensitive_data.host_keys[i]));
259 sshkey_free(sensitive_data.host_keys[i]);
260 sensitive_data.host_keys[i] = tmp;
261 }
262 /* Certs do not need demotion */
263 }
264 }
265
266 struct sshbuf *
pack_hostkeys(void)267 pack_hostkeys(void)
268 {
269 struct sshbuf *keybuf = NULL, *hostkeys = NULL;
270 int r;
271 u_int i;
272
273 if ((hostkeys = sshbuf_new()) == NULL)
274 fatal_f("sshbuf_new failed");
275
276 /* pack hostkeys into a string. Empty key slots get empty strings */
277 for (i = 0; i < options.num_host_key_files; i++) {
278 /* public key */
279 if (sensitive_data.host_pubkeys[i] != NULL) {
280 if ((r = sshkey_puts(sensitive_data.host_pubkeys[i],
281 hostkeys)) != 0)
282 fatal_fr(r, "compose hostkey public");
283 } else {
284 if ((r = sshbuf_put_string(hostkeys, NULL, 0)) != 0)
285 fatal_fr(r, "compose hostkey empty public");
286 }
287 /* cert */
288 if (sensitive_data.host_certificates[i] != NULL) {
289 if ((r = sshkey_puts(
290 sensitive_data.host_certificates[i],
291 hostkeys)) != 0)
292 fatal_fr(r, "compose host cert");
293 } else {
294 if ((r = sshbuf_put_string(hostkeys, NULL, 0)) != 0)
295 fatal_fr(r, "compose host cert empty");
296 }
297 }
298
299 sshbuf_free(keybuf);
300 return hostkeys;
301 }
302
303 static int
privsep_preauth(struct ssh * ssh)304 privsep_preauth(struct ssh *ssh)
305 {
306 int r;
307 pid_t pid;
308
309 /* Set up unprivileged child process to deal with network data */
310 pmonitor = monitor_init();
311 /* Store a pointer to the kex for later rekeying */
312 pmonitor->m_pkex = &ssh->kex;
313
314 if ((pid = fork()) == -1)
315 fatal("fork of unprivileged child failed");
316 else if (pid != 0) {
317 debug2("Network child is on pid %ld", (long)pid);
318
319 pmonitor->m_pid = pid;
320 if (have_agent) {
321 r = ssh_get_authentication_socket(&auth_sock);
322 if (r != 0) {
323 error_r(r, "Could not get agent socket");
324 have_agent = 0;
325 }
326 }
327 monitor_child_preauth(ssh, pmonitor);
328 privsep_is_preauth = 0;
329 return 1;
330 } else {
331 /* child */
332 close(pmonitor->m_sendfd);
333 close(pmonitor->m_log_recvfd);
334
335 /*
336 * Arrange unpriv-preauth child process fds:
337 * 0, 1 network socket
338 * 2 optional stderr
339 * 3 reserved
340 * 4 monitor message socket
341 * 5 monitor logging socket
342 *
343 * We know that the monitor sockets will have fds > 4 because
344 * of the reserved fds in main()
345 */
346
347 if (ssh_packet_get_connection_in(ssh) != STDIN_FILENO &&
348 dup2(ssh_packet_get_connection_in(ssh), STDIN_FILENO) == -1)
349 fatal("dup2 stdin failed: %s", strerror(errno));
350 if (ssh_packet_get_connection_out(ssh) != STDOUT_FILENO &&
351 dup2(ssh_packet_get_connection_out(ssh),
352 STDOUT_FILENO) == -1)
353 fatal("dup2 stdout failed: %s", strerror(errno));
354 /* leave stderr as-is */
355 log_redirect_stderr_to(NULL); /* dup can clobber log fd */
356 if (pmonitor->m_recvfd != PRIVSEP_MONITOR_FD &&
357 dup2(pmonitor->m_recvfd, PRIVSEP_MONITOR_FD) == -1)
358 fatal("dup2 monitor fd: %s", strerror(errno));
359 if (pmonitor->m_log_sendfd != PRIVSEP_LOG_FD &&
360 dup2(pmonitor->m_log_sendfd, PRIVSEP_LOG_FD) == -1)
361 fatal("dup2 log fd: %s", strerror(errno));
362 closefrom(PRIVSEP_MIN_FREE_FD);
363
364 saved_argv[0] = options.sshd_auth_path;
365 execv(options.sshd_auth_path, saved_argv);
366
367 fatal_f("exec of %s failed: %s",
368 options.sshd_auth_path, strerror(errno));
369 }
370 }
371
372 static void
privsep_postauth(struct ssh * ssh,Authctxt * authctxt)373 privsep_postauth(struct ssh *ssh, Authctxt *authctxt)
374 {
375 int skip_privdrop = 0;
376
377 /*
378 * Hack for systems that don't support FD passing: retain privileges
379 * in the post-auth privsep process so it can allocate PTYs directly.
380 * This is basically equivalent to what we did <= 9.7, which was to
381 * disable post-auth privsep entirely.
382 * Cygwin doesn't need to drop privs here although it doesn't support
383 * fd passing, as AFAIK PTY allocation on this platform doesn't require
384 * special privileges to begin with.
385 */
386 #if defined(DISABLE_FD_PASSING) && !defined(HAVE_CYGWIN)
387 skip_privdrop = 1;
388 #endif
389
390 /* New socket pair */
391 monitor_reinit(pmonitor);
392
393 pmonitor->m_pid = fork();
394 if (pmonitor->m_pid == -1)
395 fatal("fork of unprivileged child failed");
396 else if (pmonitor->m_pid != 0) {
397 verbose("User child is on pid %ld", (long)pmonitor->m_pid);
398 sshbuf_reset(loginmsg);
399 monitor_clear_keystate(ssh, pmonitor);
400 monitor_child_postauth(ssh, pmonitor);
401
402 /* NEVERREACHED */
403 exit(0);
404 }
405
406 /* child */
407
408 close(pmonitor->m_sendfd);
409 pmonitor->m_sendfd = -1;
410
411 /* Demote the private keys to public keys. */
412 demote_sensitive_data();
413
414 reseed_prngs();
415
416 /* Drop privileges */
417 if (!skip_privdrop)
418 do_setusercontext(authctxt->pw);
419
420 /* It is safe now to apply the key state */
421 monitor_apply_keystate(ssh, pmonitor);
422
423 /*
424 * Tell the packet layer that authentication was successful, since
425 * this information is not part of the key state.
426 */
427 ssh_packet_set_authenticated(ssh);
428 }
429
430 static struct sshkey *
get_hostkey_by_type(int type,int nid,int need_private,struct ssh * ssh)431 get_hostkey_by_type(int type, int nid, int need_private, struct ssh *ssh)
432 {
433 u_int i;
434 struct sshkey *key;
435
436 for (i = 0; i < options.num_host_key_files; i++) {
437 switch (type) {
438 case KEY_RSA_CERT:
439 case KEY_ECDSA_CERT:
440 case KEY_ED25519_CERT:
441 case KEY_ECDSA_SK_CERT:
442 case KEY_ED25519_SK_CERT:
443 case KEY_MLDSA44_ED25519_CERT:
444 key = sensitive_data.host_certificates[i];
445 break;
446 default:
447 key = sensitive_data.host_keys[i];
448 if (key == NULL && !need_private)
449 key = sensitive_data.host_pubkeys[i];
450 break;
451 }
452 if (key == NULL || key->type != type)
453 continue;
454 switch (type) {
455 case KEY_ECDSA:
456 case KEY_ECDSA_SK:
457 case KEY_ECDSA_CERT:
458 case KEY_ECDSA_SK_CERT:
459 if (key->ecdsa_nid != nid)
460 continue;
461 /* FALLTHROUGH */
462 default:
463 return need_private ?
464 sensitive_data.host_keys[i] : key;
465 }
466 }
467 return NULL;
468 }
469
470 struct sshkey *
get_hostkey_public_by_type(int type,int nid,struct ssh * ssh)471 get_hostkey_public_by_type(int type, int nid, struct ssh *ssh)
472 {
473 return get_hostkey_by_type(type, nid, 0, ssh);
474 }
475
476 struct sshkey *
get_hostkey_private_by_type(int type,int nid,struct ssh * ssh)477 get_hostkey_private_by_type(int type, int nid, struct ssh *ssh)
478 {
479 return get_hostkey_by_type(type, nid, 1, ssh);
480 }
481
482 struct sshkey *
get_hostkey_by_index(int ind)483 get_hostkey_by_index(int ind)
484 {
485 if (ind < 0 || (u_int)ind >= options.num_host_key_files)
486 return (NULL);
487 return (sensitive_data.host_keys[ind]);
488 }
489
490 struct sshkey *
get_hostkey_public_by_index(int ind,struct ssh * ssh)491 get_hostkey_public_by_index(int ind, struct ssh *ssh)
492 {
493 if (ind < 0 || (u_int)ind >= options.num_host_key_files)
494 return (NULL);
495 return (sensitive_data.host_pubkeys[ind]);
496 }
497
498 int
get_hostkey_index(struct sshkey * key,int compare,struct ssh * ssh)499 get_hostkey_index(struct sshkey *key, int compare, struct ssh *ssh)
500 {
501 u_int i;
502
503 for (i = 0; i < options.num_host_key_files; i++) {
504 if (sshkey_is_cert(key)) {
505 if (key == sensitive_data.host_certificates[i] ||
506 (compare && sensitive_data.host_certificates[i] &&
507 sshkey_equal(key,
508 sensitive_data.host_certificates[i])))
509 return (i);
510 } else {
511 if (key == sensitive_data.host_keys[i] ||
512 (compare && sensitive_data.host_keys[i] &&
513 sshkey_equal(key, sensitive_data.host_keys[i])))
514 return (i);
515 if (key == sensitive_data.host_pubkeys[i] ||
516 (compare && sensitive_data.host_pubkeys[i] &&
517 sshkey_equal(key, sensitive_data.host_pubkeys[i])))
518 return (i);
519 }
520 }
521 return (-1);
522 }
523
524 /* Inform the client of all hostkeys */
525 static void
notify_hostkeys(struct ssh * ssh)526 notify_hostkeys(struct ssh *ssh)
527 {
528 struct sshbuf *buf;
529 struct sshkey *key;
530 u_int i, nkeys;
531 int r;
532 char *fp;
533
534 /* Some clients cannot cope with the hostkeys message, skip those. */
535 if (ssh->compat & SSH_BUG_HOSTKEYS)
536 return;
537
538 if ((buf = sshbuf_new()) == NULL)
539 fatal_f("sshbuf_new");
540 for (i = nkeys = 0; i < options.num_host_key_files; i++) {
541 key = get_hostkey_public_by_index(i, ssh);
542 if (key == NULL || key->type == KEY_UNSPEC ||
543 sshkey_is_cert(key))
544 continue;
545 fp = sshkey_fingerprint(key, options.fingerprint_hash,
546 SSH_FP_DEFAULT);
547 debug3_f("key %d: %s %s", i, sshkey_ssh_name(key), fp);
548 free(fp);
549 if (nkeys == 0) {
550 /*
551 * Start building the request when we find the
552 * first usable key.
553 */
554 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
555 (r = sshpkt_put_cstring(ssh, "hostkeys-00@openssh.com")) != 0 ||
556 (r = sshpkt_put_u8(ssh, 0)) != 0) /* want reply */
557 sshpkt_fatal(ssh, r, "%s: start request", __func__);
558 }
559 /* Append the key to the request */
560 sshbuf_reset(buf);
561 if ((r = sshkey_putb(key, buf)) != 0)
562 fatal_fr(r, "couldn't put hostkey %d", i);
563 if ((r = sshpkt_put_stringb(ssh, buf)) != 0)
564 sshpkt_fatal(ssh, r, "%s: append key", __func__);
565 nkeys++;
566 }
567 debug3_f("sent %u hostkeys", nkeys);
568 if (nkeys == 0)
569 fatal_f("no hostkeys");
570 if ((r = sshpkt_send(ssh)) != 0)
571 sshpkt_fatal(ssh, r, "%s: send", __func__);
572 sshbuf_free(buf);
573 }
574
575 static void
usage(void)576 usage(void)
577 {
578 fprintf(stderr, "%s, %s\n", SSH_RELEASE, SSH_OPENSSL_VERSION);
579 fprintf(stderr,
580 "usage: sshd [-46DdeGiqTtV] [-C connection_spec] [-c host_cert_file]\n"
581 " [-E log_file] [-f config_file] [-g login_grace_time]\n"
582 " [-h host_key_file] [-o option] [-p port] [-u len]\n"
583 );
584 exit(1);
585 }
586
587 static void
parse_hostkeys(struct sshbuf * hostkeys)588 parse_hostkeys(struct sshbuf *hostkeys)
589 {
590 int r;
591 u_int num_keys = 0;
592 struct sshkey *k;
593 struct sshbuf *kbuf;
594 const u_char *cp;
595 size_t len;
596
597 while (sshbuf_len(hostkeys) != 0) {
598 if (num_keys > 2048)
599 fatal_f("too many hostkeys");
600 sensitive_data.host_keys = xrecallocarray(
601 sensitive_data.host_keys, num_keys, num_keys + 1,
602 sizeof(*sensitive_data.host_pubkeys));
603 sensitive_data.host_pubkeys = xrecallocarray(
604 sensitive_data.host_pubkeys, num_keys, num_keys + 1,
605 sizeof(*sensitive_data.host_pubkeys));
606 sensitive_data.host_certificates = xrecallocarray(
607 sensitive_data.host_certificates, num_keys, num_keys + 1,
608 sizeof(*sensitive_data.host_certificates));
609 /* private key */
610 k = NULL;
611 if ((r = sshbuf_froms(hostkeys, &kbuf)) != 0)
612 fatal_fr(r, "extract privkey");
613 if (sshbuf_len(kbuf) != 0 &&
614 (r = sshkey_private_deserialize(kbuf, &k)) != 0)
615 fatal_fr(r, "parse pubkey");
616 sensitive_data.host_keys[num_keys] = k;
617 sshbuf_free(kbuf);
618 if (k)
619 debug2_f("privkey %u: %s", num_keys, sshkey_ssh_name(k));
620 /* public key */
621 k = NULL;
622 if ((r = sshbuf_get_string_direct(hostkeys, &cp, &len)) != 0)
623 fatal_fr(r, "extract pubkey");
624 if (len != 0 && (r = sshkey_from_blob(cp, len, &k)) != 0)
625 fatal_fr(r, "parse pubkey");
626 sensitive_data.host_pubkeys[num_keys] = k;
627 if (k)
628 debug2_f("pubkey %u: %s", num_keys, sshkey_ssh_name(k));
629 /* certificate */
630 k = NULL;
631 if ((r = sshbuf_get_string_direct(hostkeys, &cp, &len)) != 0)
632 fatal_fr(r, "extract pubkey");
633 if (len != 0 && (r = sshkey_from_blob(cp, len, &k)) != 0)
634 fatal_fr(r, "parse pubkey");
635 sensitive_data.host_certificates[num_keys] = k;
636 if (k)
637 debug2_f("cert %u: %s", num_keys, sshkey_ssh_name(k));
638 num_keys++;
639 }
640 sensitive_data.num_hostkeys = num_keys;
641 }
642
643 static void
recv_rexec_state(int fd,struct sshbuf * conf,uint64_t * timing_secretp)644 recv_rexec_state(int fd, struct sshbuf *conf, uint64_t *timing_secretp)
645 {
646 struct sshbuf *m, *inc, *hostkeys;
647 u_char *cp, ver;
648 size_t len;
649 int r;
650 struct include_item *item;
651
652 debug3_f("entering fd = %d", fd);
653
654 if ((m = sshbuf_new()) == NULL || (inc = sshbuf_new()) == NULL)
655 fatal_f("sshbuf_new failed");
656
657 /* receive config */
658 if (ssh_msg_recv(fd, m) == -1)
659 fatal_f("ssh_msg_recv failed");
660 if ((r = sshbuf_get_u8(m, &ver)) != 0)
661 fatal_fr(r, "parse version");
662 if (ver != 0)
663 fatal_f("rexec version mismatch");
664 if ((r = sshbuf_get_string(m, &cp, &len)) != 0 || /* XXX _direct */
665 (r = sshbuf_get_u64(m, timing_secretp)) != 0 ||
666 (r = sshbuf_get_stringb(m, inc)) != 0)
667 fatal_fr(r, "parse config");
668
669 if (conf != NULL && (r = sshbuf_put(conf, cp, len)))
670 fatal_fr(r, "sshbuf_put");
671
672 while (sshbuf_len(inc) != 0) {
673 item = xcalloc(1, sizeof(*item));
674 if ((item->contents = sshbuf_new()) == NULL)
675 fatal_f("sshbuf_new failed");
676 if ((r = sshbuf_get_cstring(inc, &item->selector, NULL)) != 0 ||
677 (r = sshbuf_get_cstring(inc, &item->filename, NULL)) != 0 ||
678 (r = sshbuf_get_stringb(inc, item->contents)) != 0)
679 fatal_fr(r, "parse includes");
680 TAILQ_INSERT_TAIL(&includes, item, entry);
681 }
682
683 /* receive hostkeys */
684 sshbuf_reset(m);
685 if (ssh_msg_recv(fd, m) == -1)
686 fatal_f("ssh_msg_recv failed");
687 if ((r = sshbuf_get_u8(m, NULL)) != 0 ||
688 (r = sshbuf_froms(m, &hostkeys)) != 0)
689 fatal_fr(r, "parse config");
690 parse_hostkeys(hostkeys);
691
692 free(cp);
693 sshbuf_free(m);
694 sshbuf_free(hostkeys);
695 sshbuf_free(inc);
696
697 debug3_f("done");
698 }
699
700 /*
701 * If IP options are supported, make sure there are none (log and
702 * return an error if any are found). Basically we are worried about
703 * source routing; it can be used to pretend you are somebody
704 * (ip-address) you are not. That itself may be "almost acceptable"
705 * under certain circumstances, but rhosts authentication is useless
706 * if source routing is accepted. Notice also that if we just dropped
707 * source routing here, the other side could use IP spoofing to do
708 * rest of the interaction and could still bypass security. So we
709 * exit here if we detect any IP options.
710 */
711 static void
check_ip_options(struct ssh * ssh)712 check_ip_options(struct ssh *ssh)
713 {
714 #ifdef IP_OPTIONS
715 int sock_in = ssh_packet_get_connection_in(ssh);
716 struct sockaddr_storage from;
717 u_char opts[200];
718 socklen_t i, option_size = sizeof(opts), fromlen = sizeof(from);
719 char text[sizeof(opts) * 3 + 1];
720
721 memset(&from, 0, sizeof(from));
722 if (getpeername(sock_in, (struct sockaddr *)&from,
723 &fromlen) == -1)
724 return;
725 if (from.ss_family != AF_INET)
726 return;
727 /* XXX IPv6 options? */
728
729 if (getsockopt(sock_in, IPPROTO_IP, IP_OPTIONS, opts,
730 &option_size) >= 0 && option_size != 0) {
731 text[0] = '\0';
732 for (i = 0; i < option_size; i++)
733 snprintf(text + i*3, sizeof(text) - i*3,
734 " %2.2x", opts[i]);
735 fatal("Connection from %.100s port %d with IP opts: %.800s",
736 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), text);
737 }
738 #endif /* IP_OPTIONS */
739 }
740
741 /* Set the routing domain for this process */
742 static void
set_process_rdomain(struct ssh * ssh,const char * name)743 set_process_rdomain(struct ssh *ssh, const char *name)
744 {
745 #if defined(HAVE_SYS_SET_PROCESS_RDOMAIN)
746 if (name == NULL)
747 return; /* default */
748
749 if (strcmp(name, "%D") == 0) {
750 /* "expands" to routing domain of connection */
751 if ((name = ssh_packet_rdomain_in(ssh)) == NULL)
752 return;
753 }
754 /* NB. We don't pass 'ssh' to sys_set_process_rdomain() */
755 return sys_set_process_rdomain(name);
756 #elif defined(__OpenBSD__)
757 int rtable, ortable = getrtable();
758 const char *errstr;
759
760 if (name == NULL)
761 return; /* default */
762
763 if (strcmp(name, "%D") == 0) {
764 /* "expands" to routing domain of connection */
765 if ((name = ssh_packet_rdomain_in(ssh)) == NULL)
766 return;
767 }
768
769 rtable = (int)strtonum(name, 0, 255, &errstr);
770 if (errstr != NULL) /* Shouldn't happen */
771 fatal("Invalid routing domain \"%s\": %s", name, errstr);
772 if (rtable != ortable && setrtable(rtable) != 0)
773 fatal("Unable to set routing domain %d: %s",
774 rtable, strerror(errno));
775 debug_f("set routing domain %d (was %d)", rtable, ortable);
776 #else /* defined(__OpenBSD__) */
777 fatal("Unable to set routing domain: not supported in this platform");
778 #endif
779 }
780
781 /*
782 * Main program for the daemon.
783 */
784 int
main(int ac,char ** av)785 main(int ac, char **av)
786 {
787 struct ssh *ssh = NULL;
788 extern char *optarg;
789 extern int optind;
790 int devnull, r, opt, on = 1, remote_port;
791 int sock_in = -1, sock_out = -1, rexeced_flag = 0, have_key = 0;
792 const char *remote_ip, *rdomain;
793 char *line, *laddr, *logfile = NULL;
794 u_int i;
795 uint64_t ibytes, obytes;
796 mode_t new_umask;
797 Authctxt *authctxt;
798 struct connection_info *connection_info = NULL;
799 sigset_t sigmask;
800 uint64_t timing_secret = 0;
801 struct itimerval itv;
802
803 sigemptyset(&sigmask);
804 sigprocmask(SIG_SETMASK, &sigmask, NULL);
805
806 #ifdef HAVE_SECUREWARE
807 (void)set_auth_parameters(ac, av);
808 #endif
809 __progname = ssh_get_progname(av[0]);
810
811 /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */
812 saved_argc = ac;
813 saved_argv = xcalloc(ac + 1, sizeof(*saved_argv));
814 for (i = 0; (int)i < ac; i++)
815 saved_argv[i] = xstrdup(av[i]);
816 saved_argv[i] = NULL;
817
818 #ifndef HAVE_SETPROCTITLE
819 /* Prepare for later setproctitle emulation */
820 compat_init_setproctitle(ac, av);
821 av = saved_argv;
822 #endif
823
824 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
825 sanitise_stdfd();
826
827 /* Initialize configuration options to their default values. */
828 initialize_server_options(&options);
829
830 /* Parse command-line arguments. */
831 while ((opt = getopt(ac, av,
832 "C:E:b:c:f:g:h:k:o:p:u:46DGQRTdeiqrtV")) != -1) {
833 switch (opt) {
834 case '4':
835 options.address_family = AF_INET;
836 break;
837 case '6':
838 options.address_family = AF_INET6;
839 break;
840 case 'f':
841 config_file_name = optarg;
842 break;
843 case 'c':
844 servconf_add_hostcert("[command-line]", 0,
845 &options, optarg);
846 break;
847 case 'd':
848 if (debug_flag == 0) {
849 debug_flag = 1;
850 options.log_level = SYSLOG_LEVEL_DEBUG1;
851 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
852 options.log_level++;
853 break;
854 case 'D':
855 /* ignore */
856 break;
857 case 'E':
858 logfile = optarg;
859 /* FALLTHROUGH */
860 case 'e':
861 log_stderr = 1;
862 break;
863 case 'i':
864 inetd_flag = 1;
865 break;
866 case 'r':
867 /* ignore */
868 break;
869 case 'R':
870 rexeced_flag = 1;
871 break;
872 case 'Q':
873 /* ignored */
874 break;
875 case 'q':
876 options.log_level = SYSLOG_LEVEL_QUIET;
877 break;
878 case 'b':
879 /* protocol 1, ignored */
880 break;
881 case 'p':
882 options.ports_from_cmdline = 1;
883 if (options.num_ports >= MAX_PORTS) {
884 fprintf(stderr, "too many ports.\n");
885 exit(1);
886 }
887 options.ports[options.num_ports++] = a2port(optarg);
888 if (options.ports[options.num_ports-1] <= 0) {
889 fprintf(stderr, "Bad port number.\n");
890 exit(1);
891 }
892 break;
893 case 'g':
894 if ((options.login_grace_time = convtime(optarg)) == -1) {
895 fprintf(stderr, "Invalid login grace time.\n");
896 exit(1);
897 }
898 break;
899 case 'k':
900 /* protocol 1, ignored */
901 break;
902 case 'h':
903 servconf_add_hostkey("[command-line]", 0,
904 &options, optarg, 1);
905 break;
906 case 't':
907 case 'T':
908 case 'G':
909 fatal("test/dump modes not supported");
910 break;
911 case 'C':
912 connection_info = server_get_connection_info(ssh, 0, 0);
913 if (parse_server_match_testspec(connection_info,
914 optarg) == -1)
915 exit(1);
916 break;
917 case 'u':
918 utmp_len = (u_int)strtonum(optarg, 0, HOST_NAME_MAX+1+1, NULL);
919 if (utmp_len > HOST_NAME_MAX+1) {
920 fprintf(stderr, "Invalid utmp length.\n");
921 exit(1);
922 }
923 break;
924 case 'o':
925 line = xstrdup(optarg);
926 if (process_server_config_line(&options, line,
927 "command-line", 0, NULL, NULL, &includes) != 0)
928 exit(1);
929 free(line);
930 break;
931 case 'V':
932 fprintf(stderr, "%s, %s\n",
933 SSH_RELEASE, SSH_OPENSSL_VERSION);
934 exit(0);
935 default:
936 usage();
937 break;
938 }
939 }
940
941 /* Check that there are no remaining arguments. */
942 if (optind < ac) {
943 fprintf(stderr, "Extra argument %s.\n", av[optind]);
944 exit(1);
945 }
946
947 if (!rexeced_flag)
948 fatal("sshd-session should not be executed directly");
949
950 closefrom(REEXEC_MIN_FREE_FD);
951
952 platform_pre_session_start();
953
954 /* Reserve fds we'll need later for reexec things */
955 if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1)
956 fatal("open %s: %s", _PATH_DEVNULL, strerror(errno));
957 while (devnull < PRIVSEP_MIN_FREE_FD) {
958 if ((devnull = dup(devnull)) == -1)
959 fatal("dup %s: %s", _PATH_DEVNULL, strerror(errno));
960 }
961
962 seed_rng();
963
964 /* If requested, redirect the logs to the specified logfile. */
965 if (logfile != NULL) {
966 char *cp, pid_s[32];
967
968 snprintf(pid_s, sizeof(pid_s), "%ld", (unsigned long)getpid());
969 cp = percent_expand(logfile,
970 "p", pid_s,
971 "P", "sshd-session",
972 (char *)NULL);
973 log_redirect_stderr_to(cp);
974 free(cp);
975 }
976
977 /*
978 * Force logging to stderr until we have loaded the private host
979 * key (unless started from inetd)
980 */
981 log_init(__progname,
982 options.log_level == SYSLOG_LEVEL_NOT_SET ?
983 SYSLOG_LEVEL_INFO : options.log_level,
984 options.log_facility == SYSLOG_FACILITY_NOT_SET ?
985 SYSLOG_FACILITY_AUTH : options.log_facility,
986 log_stderr || !inetd_flag || debug_flag);
987
988 /* Fetch our configuration */
989 if ((cfg = sshbuf_new()) == NULL)
990 fatal("sshbuf_new config buf failed");
991 setproctitle("%s", "[rexeced]");
992 recv_rexec_state(REEXEC_CONFIG_PASS_FD, cfg, &timing_secret);
993 parse_server_config(&options, "rexec", cfg, &includes, NULL, 1);
994 /* Fill in default values for those options not explicitly set. */
995 fill_default_server_options(&options);
996 options.timing_secret = timing_secret;
997
998 /* Reinit logging in case config set Level, Facility or Verbose. */
999 log_init(__progname, options.log_level, options.log_facility,
1000 log_stderr || !inetd_flag || debug_flag);
1001
1002 debug("sshd-session version %s, %s", SSH_VERSION, SSH_OPENSSL_VERSION);
1003
1004 /* Store privilege separation user for later use if required. */
1005 privsep_chroot = (getuid() == 0 || geteuid() == 0);
1006 if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) {
1007 if (privsep_chroot || options.kerberos_authentication)
1008 fatal("Privilege separation user %s does not exist",
1009 SSH_PRIVSEP_USER);
1010 } else {
1011 privsep_pw = pwcopy(privsep_pw);
1012 freezero(privsep_pw->pw_passwd, strlen(privsep_pw->pw_passwd));
1013 privsep_pw->pw_passwd = xstrdup("*");
1014 }
1015 endpwent();
1016
1017 if (!debug_flag && !inetd_flag) {
1018 if ((startup_pipe = dup(REEXEC_CONFIG_PASS_FD)) == -1)
1019 fatal("internal error: no startup pipe");
1020
1021 /*
1022 * Signal parent that this child is at a point where
1023 * they can go away if they have a SIGHUP pending.
1024 */
1025 (void)atomicio(vwrite, startup_pipe, "\0", 1);
1026 }
1027 /* close the fd, but keep the slot reserved */
1028 if (dup2(devnull, REEXEC_CONFIG_PASS_FD) == -1)
1029 fatal("dup2 devnull->config fd: %s", strerror(errno));
1030
1031 /* Check that options are sensible */
1032 if (options.authorized_keys_command_user == NULL &&
1033 (options.authorized_keys_command != NULL &&
1034 strcasecmp(options.authorized_keys_command, "none") != 0))
1035 fatal("AuthorizedKeysCommand set without "
1036 "AuthorizedKeysCommandUser");
1037 if (options.authorized_principals_command_user == NULL &&
1038 (options.authorized_principals_command != NULL &&
1039 strcasecmp(options.authorized_principals_command, "none") != 0))
1040 fatal("AuthorizedPrincipalsCommand set without "
1041 "AuthorizedPrincipalsCommandUser");
1042
1043 /*
1044 * Check whether there is any path through configured auth methods.
1045 * Unfortunately it is not possible to verify this generally before
1046 * daemonisation in the presence of Match block, but this catches
1047 * and warns for trivial misconfigurations that could break login.
1048 */
1049 if (options.num_auth_methods != 0) {
1050 for (i = 0; i < options.num_auth_methods; i++) {
1051 if (auth2_methods_valid(options.auth_methods[i],
1052 1) == 0)
1053 break;
1054 }
1055 if (i >= options.num_auth_methods)
1056 fatal("AuthenticationMethods cannot be satisfied by "
1057 "enabled authentication methods");
1058 }
1059
1060 #ifdef WITH_OPENSSL
1061 if (options.moduli_file != NULL)
1062 dh_set_moduli_file(options.moduli_file);
1063 #endif
1064
1065 if (options.host_key_agent) {
1066 if (strcmp(options.host_key_agent, SSH_AUTHSOCKET_ENV_NAME))
1067 setenv(SSH_AUTHSOCKET_ENV_NAME,
1068 options.host_key_agent, 1);
1069 if ((r = ssh_get_authentication_socket(NULL)) == 0)
1070 have_agent = 1;
1071 else
1072 error_r(r, "Could not connect to agent \"%s\"",
1073 options.host_key_agent);
1074 }
1075
1076 if (options.num_host_key_files != sensitive_data.num_hostkeys) {
1077 fatal("internal error: hostkeys confused (config %u recvd %u)",
1078 options.num_host_key_files, sensitive_data.num_hostkeys);
1079 }
1080
1081 for (i = 0; i < options.num_host_key_files; i++) {
1082 if (sensitive_data.host_keys[i] != NULL ||
1083 (have_agent && sensitive_data.host_pubkeys[i] != NULL)) {
1084 have_key = 1;
1085 break;
1086 }
1087 }
1088 if (!have_key)
1089 fatal("internal error: monitor received no hostkeys");
1090
1091 /* Ensure that umask disallows at least group and world write */
1092 new_umask = umask(0077) | 0022;
1093 (void) umask(new_umask);
1094
1095 /* Initialize the log (it is reinitialized below in case we forked). */
1096 if (debug_flag)
1097 log_stderr = 1;
1098 log_init(__progname, options.log_level,
1099 options.log_facility, log_stderr);
1100 for (i = 0; i < options.num_log_verbose; i++)
1101 log_verbose_add(options.log_verbose[i]);
1102
1103 /* Reinitialize the log (because of the fork above). */
1104 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1105
1106 /*
1107 * Chdir to the root directory so that the current disk can be
1108 * unmounted if desired.
1109 */
1110 if (chdir("/") == -1)
1111 error("chdir(\"/\"): %s", strerror(errno));
1112
1113 /* ignore SIGPIPE */
1114 ssh_signal(SIGPIPE, SIG_IGN);
1115
1116 /* Get a connection, either from inetd or rexec */
1117 if (inetd_flag) {
1118 /*
1119 * NB. must be different fd numbers for the !socket case,
1120 * as packet_connection_is_on_socket() depends on this.
1121 */
1122 sock_in = dup(STDIN_FILENO);
1123 sock_out = dup(STDOUT_FILENO);
1124 } else {
1125 /* rexec case; accept()ed socket in ancestor listener */
1126 sock_in = sock_out = dup(STDIN_FILENO);
1127 }
1128
1129 /*
1130 * We intentionally do not close the descriptors 0, 1, and 2
1131 * as our code for setting the descriptors won't work if
1132 * ttyfd happens to be one of those.
1133 */
1134 if (stdfd_devnull(1, 1, !log_stderr) == -1)
1135 error("stdfd_devnull failed");
1136 debug("network sockets: %d, %d", sock_in, sock_out);
1137
1138 /* This is the child processing a new connection. */
1139 setproctitle("%s", "[accepted]");
1140
1141 /* Executed child processes don't need these. */
1142 FD_CLOSEONEXEC(sock_out);
1143 FD_CLOSEONEXEC(sock_in);
1144
1145 /* We will not restart on SIGHUP since it no longer makes sense. */
1146 ssh_signal(SIGALRM, SIG_DFL);
1147 ssh_signal(SIGHUP, SIG_DFL);
1148 ssh_signal(SIGTERM, SIG_DFL);
1149 ssh_signal(SIGQUIT, SIG_DFL);
1150 ssh_signal(SIGCHLD, SIG_DFL);
1151 ssh_signal(SIGINT, SIG_DFL);
1152
1153 BLOCKLIST_INIT();
1154
1155 /*
1156 * Register our connection. This turns encryption off because we do
1157 * not have a key.
1158 */
1159 if ((ssh = ssh_packet_set_connection(NULL, sock_in, sock_out)) == NULL)
1160 fatal("Unable to create connection");
1161 the_active_state = ssh;
1162 ssh_packet_set_server(ssh);
1163 ssh_packet_set_qos(ssh, options.ip_qos_interactive,
1164 options.ip_qos_bulk);
1165
1166 check_ip_options(ssh);
1167
1168 /* Prepare the channels layer */
1169 channel_init_channels(ssh);
1170 channel_set_af(ssh, options.address_family);
1171 server_process_channel_timeouts(ssh);
1172 server_process_permitopen(ssh);
1173
1174 /* Set SO_KEEPALIVE if requested. */
1175 if (options.tcp_keep_alive && ssh_packet_connection_is_on_socket(ssh) &&
1176 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) == -1)
1177 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1178
1179 if ((remote_port = ssh_remote_port(ssh)) < 0) {
1180 debug("ssh_remote_port failed");
1181 cleanup_exit(255);
1182 }
1183
1184 #ifdef HAVE_LOGIN_CAP
1185 /* Also caches remote hostname for sandboxed child. */
1186 auth_get_canonical_hostname(ssh, options.use_dns);
1187 #endif
1188
1189 /*
1190 * The rest of the code depends on the fact that
1191 * ssh_remote_ipaddr() caches the remote ip, even if
1192 * the socket goes away.
1193 */
1194 remote_ip = ssh_remote_ipaddr(ssh);
1195
1196 #ifdef SSH_AUDIT_EVENTS
1197 audit_connection_from(remote_ip, remote_port);
1198 #endif
1199
1200 rdomain = ssh_packet_rdomain_in(ssh);
1201
1202 /* Log the connection. */
1203 laddr = get_local_ipaddr(sock_in);
1204 verbose("Connection from %s port %d on %s port %d%s%s%s",
1205 remote_ip, remote_port, laddr, ssh_local_port(ssh),
1206 rdomain == NULL ? "" : " rdomain \"",
1207 rdomain == NULL ? "" : rdomain,
1208 rdomain == NULL ? "" : "\"");
1209 free(laddr);
1210
1211 /*
1212 * We don't want to listen forever unless the other side
1213 * successfully authenticates itself. So we set up an alarm which is
1214 * cleared after successful authentication. A limit of zero
1215 * indicates no limit. Note that we don't set the alarm in debugging
1216 * mode; it is just annoying to have the server exit just when you
1217 * are about to discover the bug.
1218 */
1219 ssh_signal(SIGALRM, grace_alarm_handler);
1220 if (!debug_flag && options.login_grace_time > 0) {
1221 int ujitter = arc4random_uniform(4 * 1000000);
1222
1223 timerclear(&itv.it_interval);
1224 itv.it_value.tv_sec = options.login_grace_time;
1225 itv.it_value.tv_sec += ujitter / 1000000;
1226 itv.it_value.tv_usec = ujitter % 1000000;
1227
1228 if (setitimer(ITIMER_REAL, &itv, NULL) == -1)
1229 fatal("login grace time setitimer failed");
1230 }
1231
1232 ssh_packet_set_nonblocking(ssh);
1233
1234 /* allocate authentication context */
1235 authctxt = xcalloc(1, sizeof(*authctxt));
1236 ssh->authctxt = authctxt;
1237
1238 /* XXX global for cleanup, access from other modules */
1239 the_authctxt = authctxt;
1240
1241 /* Set default key authentication options */
1242 if ((auth_opts = sshauthopt_new_with_keys_defaults()) == NULL)
1243 fatal("allocation failed");
1244
1245 /* prepare buffer to collect messages to display to user after login */
1246 if ((loginmsg = sshbuf_new()) == NULL)
1247 fatal("sshbuf_new loginmsg failed");
1248 auth_debug_reset();
1249
1250 if (privsep_preauth(ssh) != 1)
1251 fatal("privsep_preauth failed");
1252
1253 /* Now user is authenticated */
1254
1255 /*
1256 * Cancel the alarm we set to limit the time taken for
1257 * authentication.
1258 */
1259 timerclear(&itv.it_interval);
1260 timerclear(&itv.it_value);
1261 if (setitimer(ITIMER_REAL, &itv, NULL) == -1)
1262 fatal("login grace time clear failed");
1263 ssh_signal(SIGALRM, SIG_DFL);
1264 authctxt->authenticated = 1;
1265 if (startup_pipe != -1) {
1266 /* signal listener that authentication completed successfully */
1267 (void)atomicio(vwrite, startup_pipe, "\001", 1);
1268 close(startup_pipe);
1269 startup_pipe = -1;
1270 }
1271
1272 if (options.routing_domain != NULL)
1273 set_process_rdomain(ssh, options.routing_domain);
1274
1275 #ifdef SSH_AUDIT_EVENTS
1276 audit_event(ssh, SSH_AUTH_SUCCESS);
1277 #endif
1278
1279 #ifdef GSSAPI
1280 if (options.gss_authentication) {
1281 temporarily_use_uid(authctxt->pw);
1282 ssh_gssapi_storecreds();
1283 restore_uid();
1284 }
1285 #endif
1286 #ifdef USE_PAM
1287 if (options.use_pam) {
1288 do_pam_setcred();
1289 do_pam_session(ssh);
1290 }
1291 #endif
1292
1293 /*
1294 * In privilege separation, we fork another child and prepare
1295 * file descriptor passing.
1296 */
1297 privsep_postauth(ssh, authctxt);
1298 /* the monitor process [priv] will not return */
1299
1300 ssh_packet_set_timeout(ssh, options.client_alive_interval,
1301 options.client_alive_count_max);
1302
1303 /* Try to send all our hostkeys to the client */
1304 notify_hostkeys(ssh);
1305
1306 /* Start session. */
1307 do_authenticated(ssh, authctxt);
1308
1309 /* The connection has been terminated. */
1310 ssh_packet_get_bytes(ssh, &ibytes, &obytes);
1311 verbose("Transferred: sent %llu, received %llu bytes",
1312 (unsigned long long)obytes, (unsigned long long)ibytes);
1313
1314 verbose("Closing connection to %.500s port %d", remote_ip, remote_port);
1315
1316 #ifdef USE_PAM
1317 if (options.use_pam)
1318 finish_pam();
1319 #endif /* USE_PAM */
1320
1321 #ifdef SSH_AUDIT_EVENTS
1322 mm_audit_event(ssh, SSH_CONNECTION_CLOSE);
1323 #endif
1324
1325 ssh_packet_close(ssh);
1326
1327 mm_terminate();
1328
1329 exit(0);
1330 }
1331
1332 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)1333 sshd_hostkey_sign(struct ssh *ssh, struct sshkey *privkey,
1334 struct sshkey *pubkey, u_char **signature, size_t *slenp,
1335 const u_char *data, size_t dlen, const char *alg)
1336 {
1337 if (privkey) {
1338 if (mm_sshkey_sign(ssh, privkey, signature, slenp,
1339 data, dlen, alg, options.sk_provider, NULL,
1340 ssh->compat) < 0)
1341 fatal_f("privkey sign failed");
1342 } else {
1343 if (mm_sshkey_sign(ssh, pubkey, signature, slenp,
1344 data, dlen, alg, options.sk_provider, NULL,
1345 ssh->compat) < 0)
1346 fatal_f("pubkey sign failed");
1347 }
1348 return 0;
1349 }
1350
1351 /* server specific fatal cleanup */
1352 void
cleanup_exit(int i)1353 cleanup_exit(int i)
1354 {
1355 if (the_active_state != NULL && the_authctxt != NULL) {
1356 do_cleanup(the_active_state, the_authctxt);
1357 if (privsep_is_preauth &&
1358 pmonitor != NULL && pmonitor->m_pid > 1) {
1359 debug("Killing privsep child %d", pmonitor->m_pid);
1360 if (kill(pmonitor->m_pid, SIGKILL) != 0 &&
1361 errno != ESRCH) {
1362 error_f("kill(%d): %s", pmonitor->m_pid,
1363 strerror(errno));
1364 }
1365 }
1366 }
1367 #ifdef SSH_AUDIT_EVENTS
1368 /* done after do_cleanup so it can cancel the PAM auth 'thread' */
1369 if (the_active_state != NULL && mm_is_monitor())
1370 audit_event(the_active_state, SSH_CONNECTION_ABANDON);
1371 #endif
1372 /* Override default fatal exit value when auth was attempted */
1373 if (i == 255 && monitor_auth_attempted()) {
1374 BLOCKLIST_NOTIFY(the_active_state, BLOCKLIST_AUTH_FAIL,
1375 "Fatal exit");
1376 _exit(EXIT_AUTH_ATTEMPTED);
1377 }
1378 if (i == 255 && monitor_invalid_user())
1379 _exit(EXIT_INVALID_USER);
1380 _exit(i);
1381 }
1382