1 /* $OpenBSD: monitor.c,v 1.161 2016/07/22 03:39:13 djm Exp $ */
2 /*
3 * Copyright 2002 Niels Provos <provos@citi.umich.edu>
4 * Copyright 2002 Markus Friedl <markus@openbsd.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28 #include "includes.h"
29
30 #include <sys/types.h>
31 #include <sys/socket.h>
32 #include "openbsd-compat/sys-tree.h"
33 #include <sys/wait.h>
34
35 #include <errno.h>
36 #include <fcntl.h>
37 #include <limits.h>
38 #ifdef HAVE_PATHS_H
39 #include <paths.h>
40 #endif
41 #include <pwd.h>
42 #include <signal.h>
43 #ifdef HAVE_STDINT_H
44 #include <stdint.h>
45 #endif
46 #include <stdlib.h>
47 #include <string.h>
48 #include <stdarg.h>
49 #include <stdio.h>
50 #include <unistd.h>
51 #ifdef HAVE_POLL_H
52 #include <poll.h>
53 #else
54 # ifdef HAVE_SYS_POLL_H
55 # include <sys/poll.h>
56 # endif
57 #endif
58
59 #ifdef SKEY
60 #include <skey.h>
61 #endif
62
63 #ifdef WITH_OPENSSL
64 #include <openssl/dh.h>
65 #endif
66
67 #include "openbsd-compat/sys-queue.h"
68 #include "atomicio.h"
69 #include "xmalloc.h"
70 #include "ssh.h"
71 #include "key.h"
72 #include "buffer.h"
73 #include "hostfile.h"
74 #include "auth.h"
75 #include "cipher.h"
76 #include "kex.h"
77 #include "dh.h"
78 #include "auth-pam.h"
79 #ifdef TARGET_OS_MAC /* XXX Broken krb5 headers on Mac */
80 #undef TARGET_OS_MAC
81 #include "zlib.h"
82 #define TARGET_OS_MAC 1
83 #else
84 #include "zlib.h"
85 #endif
86 #include "packet.h"
87 #include "auth-options.h"
88 #include "sshpty.h"
89 #include "channels.h"
90 #include "session.h"
91 #include "sshlogin.h"
92 #include "canohost.h"
93 #include "log.h"
94 #include "misc.h"
95 #include "servconf.h"
96 #include "monitor.h"
97 #include "monitor_mm.h"
98 #ifdef GSSAPI
99 #include "ssh-gss.h"
100 #endif
101 #include "monitor_wrap.h"
102 #include "monitor_fdpass.h"
103 #include "compat.h"
104 #include "ssh2.h"
105 #include "authfd.h"
106 #include "match.h"
107 #include "ssherr.h"
108
109 #ifdef GSSAPI
110 static Gssctxt *gsscontext = NULL;
111 #endif
112
113 /* Imports */
114 extern ServerOptions options;
115 extern u_int utmp_len;
116 extern u_char session_id[];
117 extern Buffer auth_debug;
118 extern int auth_debug_init;
119 extern Buffer loginmsg;
120
121 /* State exported from the child */
122 static struct sshbuf *child_state;
123
124 /* Functions on the monitor that answer unprivileged requests */
125
126 int mm_answer_moduli(int, Buffer *);
127 int mm_answer_sign(int, Buffer *);
128 int mm_answer_pwnamallow(int, Buffer *);
129 int mm_answer_auth2_read_banner(int, Buffer *);
130 int mm_answer_authserv(int, Buffer *);
131 int mm_answer_authpassword(int, Buffer *);
132 int mm_answer_bsdauthquery(int, Buffer *);
133 int mm_answer_bsdauthrespond(int, Buffer *);
134 int mm_answer_skeyquery(int, Buffer *);
135 int mm_answer_skeyrespond(int, Buffer *);
136 int mm_answer_keyallowed(int, Buffer *);
137 int mm_answer_keyverify(int, Buffer *);
138 int mm_answer_pty(int, Buffer *);
139 int mm_answer_pty_cleanup(int, Buffer *);
140 int mm_answer_term(int, Buffer *);
141 int mm_answer_rsa_keyallowed(int, Buffer *);
142 int mm_answer_rsa_challenge(int, Buffer *);
143 int mm_answer_rsa_response(int, Buffer *);
144 int mm_answer_sesskey(int, Buffer *);
145 int mm_answer_sessid(int, Buffer *);
146
147 #ifdef USE_PAM
148 int mm_answer_pam_start(int, Buffer *);
149 int mm_answer_pam_account(int, Buffer *);
150 int mm_answer_pam_init_ctx(int, Buffer *);
151 int mm_answer_pam_query(int, Buffer *);
152 int mm_answer_pam_respond(int, Buffer *);
153 int mm_answer_pam_free_ctx(int, Buffer *);
154 #endif
155
156 #ifdef GSSAPI
157 int mm_answer_gss_setup_ctx(int, Buffer *);
158 int mm_answer_gss_accept_ctx(int, Buffer *);
159 int mm_answer_gss_userok(int, Buffer *);
160 int mm_answer_gss_checkmic(int, Buffer *);
161 #endif
162
163 #ifdef SSH_AUDIT_EVENTS
164 int mm_answer_audit_event(int, Buffer *);
165 int mm_answer_audit_command(int, Buffer *);
166 #endif
167
168 static int monitor_read_log(struct monitor *);
169
170 static Authctxt *authctxt;
171
172 #ifdef WITH_SSH1
173 static BIGNUM *ssh1_challenge = NULL; /* used for ssh1 rsa auth */
174 #endif
175
176 /* local state for key verify */
177 static u_char *key_blob = NULL;
178 static u_int key_bloblen = 0;
179 static int key_blobtype = MM_NOKEY;
180 static char *hostbased_cuser = NULL;
181 static char *hostbased_chost = NULL;
182 static char *auth_method = "unknown";
183 static char *auth_submethod = NULL;
184 static u_int session_id2_len = 0;
185 static u_char *session_id2 = NULL;
186 static pid_t monitor_child_pid;
187
188 struct mon_table {
189 enum monitor_reqtype type;
190 int flags;
191 int (*f)(int, Buffer *);
192 };
193
194 #define MON_ISAUTH 0x0004 /* Required for Authentication */
195 #define MON_AUTHDECIDE 0x0008 /* Decides Authentication */
196 #define MON_ONCE 0x0010 /* Disable after calling */
197 #define MON_ALOG 0x0020 /* Log auth attempt without authenticating */
198
199 #define MON_AUTH (MON_ISAUTH|MON_AUTHDECIDE)
200
201 #define MON_PERMIT 0x1000 /* Request is permitted */
202
203 struct mon_table mon_dispatch_proto20[] = {
204 #ifdef WITH_OPENSSL
205 {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli},
206 #endif
207 {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign},
208 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow},
209 {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv},
210 {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner},
211 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword},
212 #ifdef USE_PAM
213 {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start},
214 {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account},
215 {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx},
216 {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query},
217 {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond},
218 {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx},
219 #endif
220 #ifdef SSH_AUDIT_EVENTS
221 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
222 #endif
223 #ifdef BSD_AUTH
224 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery},
225 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond},
226 #endif
227 #ifdef SKEY
228 {MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery},
229 {MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond},
230 #endif
231 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed},
232 {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify},
233 #ifdef GSSAPI
234 {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx},
235 {MONITOR_REQ_GSSSTEP, MON_ISAUTH, mm_answer_gss_accept_ctx},
236 {MONITOR_REQ_GSSUSEROK, MON_AUTH, mm_answer_gss_userok},
237 {MONITOR_REQ_GSSCHECKMIC, MON_ISAUTH, mm_answer_gss_checkmic},
238 #endif
239 {0, 0, NULL}
240 };
241
242 struct mon_table mon_dispatch_postauth20[] = {
243 #ifdef WITH_OPENSSL
244 {MONITOR_REQ_MODULI, 0, mm_answer_moduli},
245 #endif
246 {MONITOR_REQ_SIGN, 0, mm_answer_sign},
247 {MONITOR_REQ_PTY, 0, mm_answer_pty},
248 {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup},
249 {MONITOR_REQ_TERM, 0, mm_answer_term},
250 #ifdef SSH_AUDIT_EVENTS
251 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
252 {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT, mm_answer_audit_command},
253 #endif
254 {0, 0, NULL}
255 };
256
257 struct mon_table mon_dispatch_proto15[] = {
258 #ifdef WITH_SSH1
259 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow},
260 {MONITOR_REQ_SESSKEY, MON_ONCE, mm_answer_sesskey},
261 {MONITOR_REQ_SESSID, MON_ONCE, mm_answer_sessid},
262 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword},
263 {MONITOR_REQ_RSAKEYALLOWED, MON_ISAUTH|MON_ALOG, mm_answer_rsa_keyallowed},
264 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH|MON_ALOG, mm_answer_keyallowed},
265 {MONITOR_REQ_RSACHALLENGE, MON_ONCE, mm_answer_rsa_challenge},
266 {MONITOR_REQ_RSARESPONSE, MON_ONCE|MON_AUTHDECIDE, mm_answer_rsa_response},
267 #ifdef BSD_AUTH
268 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery},
269 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond},
270 #endif
271 #ifdef SKEY
272 {MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery},
273 {MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond},
274 #endif
275 #ifdef USE_PAM
276 {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start},
277 {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account},
278 {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx},
279 {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query},
280 {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond},
281 {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx},
282 #endif
283 #ifdef SSH_AUDIT_EVENTS
284 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
285 #endif
286 #endif /* WITH_SSH1 */
287 {0, 0, NULL}
288 };
289
290 struct mon_table mon_dispatch_postauth15[] = {
291 #ifdef WITH_SSH1
292 {MONITOR_REQ_PTY, MON_ONCE, mm_answer_pty},
293 {MONITOR_REQ_PTYCLEANUP, MON_ONCE, mm_answer_pty_cleanup},
294 {MONITOR_REQ_TERM, 0, mm_answer_term},
295 #ifdef SSH_AUDIT_EVENTS
296 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
297 {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT|MON_ONCE, mm_answer_audit_command},
298 #endif
299 #endif /* WITH_SSH1 */
300 {0, 0, NULL}
301 };
302
303 struct mon_table *mon_dispatch;
304
305 /* Specifies if a certain message is allowed at the moment */
306
307 static void
monitor_permit(struct mon_table * ent,enum monitor_reqtype type,int permit)308 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit)
309 {
310 while (ent->f != NULL) {
311 if (ent->type == type) {
312 ent->flags &= ~MON_PERMIT;
313 ent->flags |= permit ? MON_PERMIT : 0;
314 return;
315 }
316 ent++;
317 }
318 }
319
320 static void
monitor_permit_authentications(int permit)321 monitor_permit_authentications(int permit)
322 {
323 struct mon_table *ent = mon_dispatch;
324
325 while (ent->f != NULL) {
326 if (ent->flags & MON_AUTH) {
327 ent->flags &= ~MON_PERMIT;
328 ent->flags |= permit ? MON_PERMIT : 0;
329 }
330 ent++;
331 }
332 }
333
334 void
monitor_child_preauth(Authctxt * _authctxt,struct monitor * pmonitor)335 monitor_child_preauth(Authctxt *_authctxt, struct monitor *pmonitor)
336 {
337 struct mon_table *ent;
338 int authenticated = 0, partial = 0;
339
340 debug3("preauth child monitor started");
341
342 close(pmonitor->m_recvfd);
343 close(pmonitor->m_log_sendfd);
344 pmonitor->m_log_sendfd = pmonitor->m_recvfd = -1;
345
346 authctxt = _authctxt;
347 memset(authctxt, 0, sizeof(*authctxt));
348
349 authctxt->loginmsg = &loginmsg;
350
351 if (compat20) {
352 mon_dispatch = mon_dispatch_proto20;
353
354 /* Permit requests for moduli and signatures */
355 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
356 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
357 } else {
358 mon_dispatch = mon_dispatch_proto15;
359
360 monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 1);
361 }
362
363 /* The first few requests do not require asynchronous access */
364 while (!authenticated) {
365 partial = 0;
366 auth_method = "unknown";
367 auth_submethod = NULL;
368 authenticated = (monitor_read(pmonitor, mon_dispatch, &ent) == 1);
369
370 /* Special handling for multiple required authentications */
371 if (options.num_auth_methods != 0) {
372 if (!compat20)
373 fatal("AuthenticationMethods is not supported"
374 "with SSH protocol 1");
375 if (authenticated &&
376 !auth2_update_methods_lists(authctxt,
377 auth_method, auth_submethod)) {
378 debug3("%s: method %s: partial", __func__,
379 auth_method);
380 authenticated = 0;
381 partial = 1;
382 }
383 }
384
385 if (authenticated) {
386 if (!(ent->flags & MON_AUTHDECIDE))
387 fatal("%s: unexpected authentication from %d",
388 __func__, ent->type);
389 if (authctxt->pw->pw_uid == 0 &&
390 !auth_root_allowed(auth_method))
391 authenticated = 0;
392 #ifdef USE_PAM
393 /* PAM needs to perform account checks after auth */
394 if (options.use_pam && authenticated) {
395 Buffer m;
396
397 buffer_init(&m);
398 mm_request_receive_expect(pmonitor->m_sendfd,
399 MONITOR_REQ_PAM_ACCOUNT, &m);
400 authenticated = mm_answer_pam_account(pmonitor->m_sendfd, &m);
401 buffer_free(&m);
402 }
403 #endif
404 }
405 if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) {
406 auth_log(authctxt, authenticated, partial,
407 auth_method, auth_submethod);
408 if (!partial && !authenticated)
409 authctxt->failures++;
410 }
411 }
412
413 if (!authctxt->valid)
414 fatal("%s: authenticated invalid user", __func__);
415 if (strcmp(auth_method, "unknown") == 0)
416 fatal("%s: authentication method name unknown", __func__);
417
418 debug("%s: %s has been authenticated by privileged process",
419 __func__, authctxt->user);
420
421 mm_get_keystate(pmonitor);
422
423 /* Drain any buffered messages from the child */
424 while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0)
425 ;
426
427 close(pmonitor->m_sendfd);
428 close(pmonitor->m_log_recvfd);
429 pmonitor->m_sendfd = pmonitor->m_log_recvfd = -1;
430 }
431
432 static void
monitor_set_child_handler(pid_t pid)433 monitor_set_child_handler(pid_t pid)
434 {
435 monitor_child_pid = pid;
436 }
437
438 static void
monitor_child_handler(int sig)439 monitor_child_handler(int sig)
440 {
441 kill(monitor_child_pid, sig);
442 }
443
444 void
monitor_child_postauth(struct monitor * pmonitor)445 monitor_child_postauth(struct monitor *pmonitor)
446 {
447 close(pmonitor->m_recvfd);
448 pmonitor->m_recvfd = -1;
449
450 monitor_set_child_handler(pmonitor->m_pid);
451 signal(SIGHUP, &monitor_child_handler);
452 signal(SIGTERM, &monitor_child_handler);
453 signal(SIGINT, &monitor_child_handler);
454 #ifdef SIGXFSZ
455 signal(SIGXFSZ, SIG_IGN);
456 #endif
457
458 if (compat20) {
459 mon_dispatch = mon_dispatch_postauth20;
460
461 /* Permit requests for moduli and signatures */
462 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
463 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
464 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1);
465 } else {
466 mon_dispatch = mon_dispatch_postauth15;
467 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1);
468 }
469 if (!no_pty_flag) {
470 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1);
471 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1);
472 }
473
474 for (;;)
475 monitor_read(pmonitor, mon_dispatch, NULL);
476 }
477
478 void
monitor_sync(struct monitor * pmonitor)479 monitor_sync(struct monitor *pmonitor)
480 {
481 if (options.compression) {
482 /* The member allocation is not visible, so sync it */
483 mm_share_sync(&pmonitor->m_zlib, &pmonitor->m_zback);
484 }
485 }
486
487 /* Allocation functions for zlib */
488 static void *
mm_zalloc(struct mm_master * mm,u_int ncount,u_int size)489 mm_zalloc(struct mm_master *mm, u_int ncount, u_int size)
490 {
491 if (size == 0 || ncount == 0 || ncount > SIZE_MAX / size)
492 fatal("%s: mm_zalloc(%u, %u)", __func__, ncount, size);
493
494 return mm_malloc(mm, size * ncount);
495 }
496
497 static void
mm_zfree(struct mm_master * mm,void * address)498 mm_zfree(struct mm_master *mm, void *address)
499 {
500 mm_free(mm, address);
501 }
502
503 static int
monitor_read_log(struct monitor * pmonitor)504 monitor_read_log(struct monitor *pmonitor)
505 {
506 Buffer logmsg;
507 u_int len, level;
508 char *msg;
509
510 buffer_init(&logmsg);
511
512 /* Read length */
513 buffer_append_space(&logmsg, 4);
514 if (atomicio(read, pmonitor->m_log_recvfd,
515 buffer_ptr(&logmsg), buffer_len(&logmsg)) != buffer_len(&logmsg)) {
516 if (errno == EPIPE) {
517 buffer_free(&logmsg);
518 debug("%s: child log fd closed", __func__);
519 close(pmonitor->m_log_recvfd);
520 pmonitor->m_log_recvfd = -1;
521 return -1;
522 }
523 fatal("%s: log fd read: %s", __func__, strerror(errno));
524 }
525 len = buffer_get_int(&logmsg);
526 if (len <= 4 || len > 8192)
527 fatal("%s: invalid log message length %u", __func__, len);
528
529 /* Read severity, message */
530 buffer_clear(&logmsg);
531 buffer_append_space(&logmsg, len);
532 if (atomicio(read, pmonitor->m_log_recvfd,
533 buffer_ptr(&logmsg), buffer_len(&logmsg)) != buffer_len(&logmsg))
534 fatal("%s: log fd read: %s", __func__, strerror(errno));
535
536 /* Log it */
537 level = buffer_get_int(&logmsg);
538 msg = buffer_get_string(&logmsg, NULL);
539 if (log_level_name(level) == NULL)
540 fatal("%s: invalid log level %u (corrupted message?)",
541 __func__, level);
542 do_log2(level, "%s [preauth]", msg);
543
544 buffer_free(&logmsg);
545 free(msg);
546
547 return 0;
548 }
549
550 int
monitor_read(struct monitor * pmonitor,struct mon_table * ent,struct mon_table ** pent)551 monitor_read(struct monitor *pmonitor, struct mon_table *ent,
552 struct mon_table **pent)
553 {
554 Buffer m;
555 int ret;
556 u_char type;
557 struct pollfd pfd[2];
558
559 for (;;) {
560 memset(&pfd, 0, sizeof(pfd));
561 pfd[0].fd = pmonitor->m_sendfd;
562 pfd[0].events = POLLIN;
563 pfd[1].fd = pmonitor->m_log_recvfd;
564 pfd[1].events = pfd[1].fd == -1 ? 0 : POLLIN;
565 if (poll(pfd, pfd[1].fd == -1 ? 1 : 2, -1) == -1) {
566 if (errno == EINTR || errno == EAGAIN)
567 continue;
568 fatal("%s: poll: %s", __func__, strerror(errno));
569 }
570 if (pfd[1].revents) {
571 /*
572 * Drain all log messages before processing next
573 * monitor request.
574 */
575 monitor_read_log(pmonitor);
576 continue;
577 }
578 if (pfd[0].revents)
579 break; /* Continues below */
580 }
581
582 buffer_init(&m);
583
584 mm_request_receive(pmonitor->m_sendfd, &m);
585 type = buffer_get_char(&m);
586
587 debug3("%s: checking request %d", __func__, type);
588
589 while (ent->f != NULL) {
590 if (ent->type == type)
591 break;
592 ent++;
593 }
594
595 if (ent->f != NULL) {
596 if (!(ent->flags & MON_PERMIT))
597 fatal("%s: unpermitted request %d", __func__,
598 type);
599 ret = (*ent->f)(pmonitor->m_sendfd, &m);
600 buffer_free(&m);
601
602 /* The child may use this request only once, disable it */
603 if (ent->flags & MON_ONCE) {
604 debug2("%s: %d used once, disabling now", __func__,
605 type);
606 ent->flags &= ~MON_PERMIT;
607 }
608
609 if (pent != NULL)
610 *pent = ent;
611
612 return ret;
613 }
614
615 fatal("%s: unsupported request: %d", __func__, type);
616
617 /* NOTREACHED */
618 return (-1);
619 }
620
621 /* allowed key state */
622 static int
monitor_allowed_key(u_char * blob,u_int bloblen)623 monitor_allowed_key(u_char *blob, u_int bloblen)
624 {
625 /* make sure key is allowed */
626 if (key_blob == NULL || key_bloblen != bloblen ||
627 timingsafe_bcmp(key_blob, blob, key_bloblen))
628 return (0);
629 return (1);
630 }
631
632 static void
monitor_reset_key_state(void)633 monitor_reset_key_state(void)
634 {
635 /* reset state */
636 free(key_blob);
637 free(hostbased_cuser);
638 free(hostbased_chost);
639 key_blob = NULL;
640 key_bloblen = 0;
641 key_blobtype = MM_NOKEY;
642 hostbased_cuser = NULL;
643 hostbased_chost = NULL;
644 }
645
646 #ifdef WITH_OPENSSL
647 int
mm_answer_moduli(int sock,Buffer * m)648 mm_answer_moduli(int sock, Buffer *m)
649 {
650 DH *dh;
651 int min, want, max;
652
653 min = buffer_get_int(m);
654 want = buffer_get_int(m);
655 max = buffer_get_int(m);
656
657 debug3("%s: got parameters: %d %d %d",
658 __func__, min, want, max);
659 /* We need to check here, too, in case the child got corrupted */
660 if (max < min || want < min || max < want)
661 fatal("%s: bad parameters: %d %d %d",
662 __func__, min, want, max);
663
664 buffer_clear(m);
665
666 dh = choose_dh(min, want, max);
667 if (dh == NULL) {
668 buffer_put_char(m, 0);
669 return (0);
670 } else {
671 /* Send first bignum */
672 buffer_put_char(m, 1);
673 buffer_put_bignum2(m, dh->p);
674 buffer_put_bignum2(m, dh->g);
675
676 DH_free(dh);
677 }
678 mm_request_send(sock, MONITOR_ANS_MODULI, m);
679 return (0);
680 }
681 #endif
682
683 int
mm_answer_sign(int sock,Buffer * m)684 mm_answer_sign(int sock, Buffer *m)
685 {
686 struct ssh *ssh = active_state; /* XXX */
687 extern int auth_sock; /* XXX move to state struct? */
688 struct sshkey *key;
689 struct sshbuf *sigbuf = NULL;
690 u_char *p = NULL, *signature = NULL;
691 char *alg = NULL;
692 size_t datlen, siglen, alglen;
693 int r, is_proof = 0;
694 u_int keyid;
695 const char proof_req[] = "hostkeys-prove-00@openssh.com";
696
697 debug3("%s", __func__);
698
699 if ((r = sshbuf_get_u32(m, &keyid)) != 0 ||
700 (r = sshbuf_get_string(m, &p, &datlen)) != 0 ||
701 (r = sshbuf_get_cstring(m, &alg, &alglen)) != 0)
702 fatal("%s: buffer error: %s", __func__, ssh_err(r));
703 if (keyid > INT_MAX)
704 fatal("%s: invalid key ID", __func__);
705
706 /*
707 * Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes),
708 * SHA384 (48 bytes) and SHA512 (64 bytes).
709 *
710 * Otherwise, verify the signature request is for a hostkey
711 * proof.
712 *
713 * XXX perform similar check for KEX signature requests too?
714 * it's not trivial, since what is signed is the hash, rather
715 * than the full kex structure...
716 */
717 if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64) {
718 /*
719 * Construct expected hostkey proof and compare it to what
720 * the client sent us.
721 */
722 if (session_id2_len == 0) /* hostkeys is never first */
723 fatal("%s: bad data length: %zu", __func__, datlen);
724 if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL)
725 fatal("%s: no hostkey for index %d", __func__, keyid);
726 if ((sigbuf = sshbuf_new()) == NULL)
727 fatal("%s: sshbuf_new", __func__);
728 if ((r = sshbuf_put_cstring(sigbuf, proof_req)) != 0 ||
729 (r = sshbuf_put_string(sigbuf, session_id2,
730 session_id2_len)) != 0 ||
731 (r = sshkey_puts(key, sigbuf)) != 0)
732 fatal("%s: couldn't prepare private key "
733 "proof buffer: %s", __func__, ssh_err(r));
734 if (datlen != sshbuf_len(sigbuf) ||
735 memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0)
736 fatal("%s: bad data length: %zu, hostkey proof len %zu",
737 __func__, datlen, sshbuf_len(sigbuf));
738 sshbuf_free(sigbuf);
739 is_proof = 1;
740 }
741
742 /* save session id, it will be passed on the first call */
743 if (session_id2_len == 0) {
744 session_id2_len = datlen;
745 session_id2 = xmalloc(session_id2_len);
746 memcpy(session_id2, p, session_id2_len);
747 }
748
749 if ((key = get_hostkey_by_index(keyid)) != NULL) {
750 if ((r = sshkey_sign(key, &signature, &siglen, p, datlen, alg,
751 datafellows)) != 0)
752 fatal("%s: sshkey_sign failed: %s",
753 __func__, ssh_err(r));
754 } else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL &&
755 auth_sock > 0) {
756 if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen,
757 p, datlen, alg, datafellows)) != 0) {
758 fatal("%s: ssh_agent_sign failed: %s",
759 __func__, ssh_err(r));
760 }
761 } else
762 fatal("%s: no hostkey from index %d", __func__, keyid);
763
764 debug3("%s: %s signature %p(%zu)", __func__,
765 is_proof ? "KEX" : "hostkey proof", signature, siglen);
766
767 sshbuf_reset(m);
768 if ((r = sshbuf_put_string(m, signature, siglen)) != 0)
769 fatal("%s: buffer error: %s", __func__, ssh_err(r));
770
771 free(alg);
772 free(p);
773 free(signature);
774
775 mm_request_send(sock, MONITOR_ANS_SIGN, m);
776
777 /* Turn on permissions for getpwnam */
778 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1);
779
780 return (0);
781 }
782
783 /* Retrieves the password entry and also checks if the user is permitted */
784
785 int
mm_answer_pwnamallow(int sock,Buffer * m)786 mm_answer_pwnamallow(int sock, Buffer *m)
787 {
788 char *username;
789 struct passwd *pwent;
790 int allowed = 0;
791 u_int i;
792
793 debug3("%s", __func__);
794
795 if (authctxt->attempt++ != 0)
796 fatal("%s: multiple attempts for getpwnam", __func__);
797
798 username = buffer_get_string(m, NULL);
799
800 pwent = getpwnamallow(username);
801
802 authctxt->user = xstrdup(username);
803 setproctitle("%s [priv]", pwent ? username : "unknown");
804 free(username);
805
806 buffer_clear(m);
807
808 if (pwent == NULL) {
809 buffer_put_char(m, 0);
810 authctxt->pw = fakepw();
811 goto out;
812 }
813
814 allowed = 1;
815 authctxt->pw = pwent;
816 authctxt->valid = 1;
817
818 buffer_put_char(m, 1);
819 buffer_put_string(m, pwent, sizeof(struct passwd));
820 buffer_put_cstring(m, pwent->pw_name);
821 buffer_put_cstring(m, "*");
822 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS
823 buffer_put_cstring(m, pwent->pw_gecos);
824 #endif
825 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS
826 buffer_put_cstring(m, pwent->pw_class);
827 #endif
828 buffer_put_cstring(m, pwent->pw_dir);
829 buffer_put_cstring(m, pwent->pw_shell);
830
831 out:
832 buffer_put_string(m, &options, sizeof(options));
833
834 #define M_CP_STROPT(x) do { \
835 if (options.x != NULL) \
836 buffer_put_cstring(m, options.x); \
837 } while (0)
838 #define M_CP_STRARRAYOPT(x, nx) do { \
839 for (i = 0; i < options.nx; i++) \
840 buffer_put_cstring(m, options.x[i]); \
841 } while (0)
842 /* See comment in servconf.h */
843 COPY_MATCH_STRING_OPTS();
844 #undef M_CP_STROPT
845 #undef M_CP_STRARRAYOPT
846
847 /* Create valid auth method lists */
848 if (compat20 && auth2_setup_methods_lists(authctxt) != 0) {
849 /*
850 * The monitor will continue long enough to let the child
851 * run to it's packet_disconnect(), but it must not allow any
852 * authentication to succeed.
853 */
854 debug("%s: no valid authentication method lists", __func__);
855 }
856
857 debug3("%s: sending MONITOR_ANS_PWNAM: %d", __func__, allowed);
858 mm_request_send(sock, MONITOR_ANS_PWNAM, m);
859
860 /* For SSHv1 allow authentication now */
861 if (!compat20)
862 monitor_permit_authentications(1);
863 else {
864 /* Allow service/style information on the auth context */
865 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1);
866 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1);
867 }
868 #ifdef USE_PAM
869 if (options.use_pam)
870 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1);
871 #endif
872
873 return (0);
874 }
875
mm_answer_auth2_read_banner(int sock,Buffer * m)876 int mm_answer_auth2_read_banner(int sock, Buffer *m)
877 {
878 char *banner;
879
880 buffer_clear(m);
881 banner = auth2_read_banner();
882 buffer_put_cstring(m, banner != NULL ? banner : "");
883 mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m);
884 free(banner);
885
886 return (0);
887 }
888
889 int
mm_answer_authserv(int sock,Buffer * m)890 mm_answer_authserv(int sock, Buffer *m)
891 {
892 monitor_permit_authentications(1);
893
894 authctxt->service = buffer_get_string(m, NULL);
895 authctxt->style = buffer_get_string(m, NULL);
896 debug3("%s: service=%s, style=%s",
897 __func__, authctxt->service, authctxt->style);
898
899 if (strlen(authctxt->style) == 0) {
900 free(authctxt->style);
901 authctxt->style = NULL;
902 }
903
904 return (0);
905 }
906
907 int
mm_answer_authpassword(int sock,Buffer * m)908 mm_answer_authpassword(int sock, Buffer *m)
909 {
910 static int call_count;
911 char *passwd;
912 int authenticated;
913 u_int plen;
914
915 passwd = buffer_get_string(m, &plen);
916 /* Only authenticate if the context is valid */
917 authenticated = options.password_authentication &&
918 auth_password(authctxt, passwd);
919 explicit_bzero(passwd, strlen(passwd));
920 free(passwd);
921
922 buffer_clear(m);
923 buffer_put_int(m, authenticated);
924 #ifdef USE_PAM
925 buffer_put_int(m, sshpam_get_maxtries_reached());
926 #endif
927
928 debug3("%s: sending result %d", __func__, authenticated);
929 mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m);
930
931 call_count++;
932 if (plen == 0 && call_count == 1)
933 auth_method = "none";
934 else
935 auth_method = "password";
936
937 /* Causes monitor loop to terminate if authenticated */
938 return (authenticated);
939 }
940
941 #ifdef BSD_AUTH
942 int
mm_answer_bsdauthquery(int sock,Buffer * m)943 mm_answer_bsdauthquery(int sock, Buffer *m)
944 {
945 char *name, *infotxt;
946 u_int numprompts;
947 u_int *echo_on;
948 char **prompts;
949 u_int success;
950
951 success = bsdauth_query(authctxt, &name, &infotxt, &numprompts,
952 &prompts, &echo_on) < 0 ? 0 : 1;
953
954 buffer_clear(m);
955 buffer_put_int(m, success);
956 if (success)
957 buffer_put_cstring(m, prompts[0]);
958
959 debug3("%s: sending challenge success: %u", __func__, success);
960 mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m);
961
962 if (success) {
963 free(name);
964 free(infotxt);
965 free(prompts);
966 free(echo_on);
967 }
968
969 return (0);
970 }
971
972 int
mm_answer_bsdauthrespond(int sock,Buffer * m)973 mm_answer_bsdauthrespond(int sock, Buffer *m)
974 {
975 char *response;
976 int authok;
977
978 if (authctxt->as == NULL)
979 fatal("%s: no bsd auth session", __func__);
980
981 response = buffer_get_string(m, NULL);
982 authok = options.challenge_response_authentication &&
983 auth_userresponse(authctxt->as, response, 0);
984 authctxt->as = NULL;
985 debug3("%s: <%s> = <%d>", __func__, response, authok);
986 free(response);
987
988 buffer_clear(m);
989 buffer_put_int(m, authok);
990
991 debug3("%s: sending authenticated: %d", __func__, authok);
992 mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m);
993
994 if (compat20) {
995 auth_method = "keyboard-interactive";
996 auth_submethod = "bsdauth";
997 } else
998 auth_method = "bsdauth";
999
1000 return (authok != 0);
1001 }
1002 #endif
1003
1004 #ifdef SKEY
1005 int
mm_answer_skeyquery(int sock,Buffer * m)1006 mm_answer_skeyquery(int sock, Buffer *m)
1007 {
1008 struct skey skey;
1009 char challenge[1024];
1010 u_int success;
1011
1012 success = _compat_skeychallenge(&skey, authctxt->user, challenge,
1013 sizeof(challenge)) < 0 ? 0 : 1;
1014
1015 buffer_clear(m);
1016 buffer_put_int(m, success);
1017 if (success)
1018 buffer_put_cstring(m, challenge);
1019
1020 debug3("%s: sending challenge success: %u", __func__, success);
1021 mm_request_send(sock, MONITOR_ANS_SKEYQUERY, m);
1022
1023 return (0);
1024 }
1025
1026 int
mm_answer_skeyrespond(int sock,Buffer * m)1027 mm_answer_skeyrespond(int sock, Buffer *m)
1028 {
1029 char *response;
1030 int authok;
1031
1032 response = buffer_get_string(m, NULL);
1033
1034 authok = (options.challenge_response_authentication &&
1035 authctxt->valid &&
1036 skey_haskey(authctxt->pw->pw_name) == 0 &&
1037 skey_passcheck(authctxt->pw->pw_name, response) != -1);
1038
1039 free(response);
1040
1041 buffer_clear(m);
1042 buffer_put_int(m, authok);
1043
1044 debug3("%s: sending authenticated: %d", __func__, authok);
1045 mm_request_send(sock, MONITOR_ANS_SKEYRESPOND, m);
1046
1047 auth_method = "keyboard-interactive";
1048 auth_submethod = "skey";
1049
1050 return (authok != 0);
1051 }
1052 #endif
1053
1054 #ifdef USE_PAM
1055 int
mm_answer_pam_start(int sock,Buffer * m)1056 mm_answer_pam_start(int sock, Buffer *m)
1057 {
1058 if (!options.use_pam)
1059 fatal("UsePAM not set, but ended up in %s anyway", __func__);
1060
1061 start_pam(authctxt);
1062
1063 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1);
1064
1065 return (0);
1066 }
1067
1068 int
mm_answer_pam_account(int sock,Buffer * m)1069 mm_answer_pam_account(int sock, Buffer *m)
1070 {
1071 u_int ret;
1072
1073 if (!options.use_pam)
1074 fatal("UsePAM not set, but ended up in %s anyway", __func__);
1075
1076 ret = do_pam_account();
1077
1078 buffer_put_int(m, ret);
1079 buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg));
1080
1081 mm_request_send(sock, MONITOR_ANS_PAM_ACCOUNT, m);
1082
1083 return (ret);
1084 }
1085
1086 static void *sshpam_ctxt, *sshpam_authok;
1087 extern KbdintDevice sshpam_device;
1088
1089 int
mm_answer_pam_init_ctx(int sock,Buffer * m)1090 mm_answer_pam_init_ctx(int sock, Buffer *m)
1091 {
1092 debug3("%s", __func__);
1093 sshpam_ctxt = (sshpam_device.init_ctx)(authctxt);
1094 sshpam_authok = NULL;
1095 buffer_clear(m);
1096 if (sshpam_ctxt != NULL) {
1097 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1);
1098 buffer_put_int(m, 1);
1099 } else {
1100 buffer_put_int(m, 0);
1101 }
1102 mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m);
1103 return (0);
1104 }
1105
1106 int
mm_answer_pam_query(int sock,Buffer * m)1107 mm_answer_pam_query(int sock, Buffer *m)
1108 {
1109 char *name = NULL, *info = NULL, **prompts = NULL;
1110 u_int i, num = 0, *echo_on = 0;
1111 int ret;
1112
1113 debug3("%s", __func__);
1114 sshpam_authok = NULL;
1115 ret = (sshpam_device.query)(sshpam_ctxt, &name, &info, &num, &prompts, &echo_on);
1116 if (ret == 0 && num == 0)
1117 sshpam_authok = sshpam_ctxt;
1118 if (num > 1 || name == NULL || info == NULL)
1119 ret = -1;
1120 buffer_clear(m);
1121 buffer_put_int(m, ret);
1122 buffer_put_cstring(m, name);
1123 free(name);
1124 buffer_put_cstring(m, info);
1125 free(info);
1126 buffer_put_int(m, sshpam_get_maxtries_reached());
1127 buffer_put_int(m, num);
1128 for (i = 0; i < num; ++i) {
1129 buffer_put_cstring(m, prompts[i]);
1130 free(prompts[i]);
1131 buffer_put_int(m, echo_on[i]);
1132 }
1133 free(prompts);
1134 free(echo_on);
1135 auth_method = "keyboard-interactive";
1136 auth_submethod = "pam";
1137 mm_request_send(sock, MONITOR_ANS_PAM_QUERY, m);
1138 return (0);
1139 }
1140
1141 int
mm_answer_pam_respond(int sock,Buffer * m)1142 mm_answer_pam_respond(int sock, Buffer *m)
1143 {
1144 char **resp;
1145 u_int i, num;
1146 int ret;
1147
1148 debug3("%s", __func__);
1149 sshpam_authok = NULL;
1150 num = buffer_get_int(m);
1151 if (num > 0) {
1152 resp = xcalloc(num, sizeof(char *));
1153 for (i = 0; i < num; ++i)
1154 resp[i] = buffer_get_string(m, NULL);
1155 ret = (sshpam_device.respond)(sshpam_ctxt, num, resp);
1156 for (i = 0; i < num; ++i)
1157 free(resp[i]);
1158 free(resp);
1159 } else {
1160 ret = (sshpam_device.respond)(sshpam_ctxt, num, NULL);
1161 }
1162 buffer_clear(m);
1163 buffer_put_int(m, ret);
1164 mm_request_send(sock, MONITOR_ANS_PAM_RESPOND, m);
1165 auth_method = "keyboard-interactive";
1166 auth_submethod = "pam";
1167 if (ret == 0)
1168 sshpam_authok = sshpam_ctxt;
1169 return (0);
1170 }
1171
1172 int
mm_answer_pam_free_ctx(int sock,Buffer * m)1173 mm_answer_pam_free_ctx(int sock, Buffer *m)
1174 {
1175 int r = sshpam_authok != NULL && sshpam_authok == sshpam_ctxt;
1176
1177 debug3("%s", __func__);
1178 (sshpam_device.free_ctx)(sshpam_ctxt);
1179 sshpam_ctxt = sshpam_authok = NULL;
1180 buffer_clear(m);
1181 mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m);
1182 auth_method = "keyboard-interactive";
1183 auth_submethod = "pam";
1184 return r;
1185 }
1186 #endif
1187
1188 int
mm_answer_keyallowed(int sock,Buffer * m)1189 mm_answer_keyallowed(int sock, Buffer *m)
1190 {
1191 Key *key;
1192 char *cuser, *chost;
1193 u_char *blob;
1194 u_int bloblen, pubkey_auth_attempt;
1195 enum mm_keytype type = 0;
1196 int allowed = 0;
1197
1198 debug3("%s entering", __func__);
1199
1200 type = buffer_get_int(m);
1201 cuser = buffer_get_string(m, NULL);
1202 chost = buffer_get_string(m, NULL);
1203 blob = buffer_get_string(m, &bloblen);
1204 pubkey_auth_attempt = buffer_get_int(m);
1205
1206 key = key_from_blob(blob, bloblen);
1207
1208 if ((compat20 && type == MM_RSAHOSTKEY) ||
1209 (!compat20 && type != MM_RSAHOSTKEY))
1210 fatal("%s: key type and protocol mismatch", __func__);
1211
1212 debug3("%s: key_from_blob: %p", __func__, key);
1213
1214 if (key != NULL && authctxt->valid) {
1215 /* These should not make it past the privsep child */
1216 if (key_type_plain(key->type) == KEY_RSA &&
1217 (datafellows & SSH_BUG_RSASIGMD5) != 0)
1218 fatal("%s: passed a SSH_BUG_RSASIGMD5 key", __func__);
1219
1220 switch (type) {
1221 case MM_USERKEY:
1222 allowed = options.pubkey_authentication &&
1223 !auth2_userkey_already_used(authctxt, key) &&
1224 match_pattern_list(sshkey_ssh_name(key),
1225 options.pubkey_key_types, 0) == 1 &&
1226 user_key_allowed(authctxt->pw, key,
1227 pubkey_auth_attempt);
1228 pubkey_auth_info(authctxt, key, NULL);
1229 auth_method = "publickey";
1230 if (options.pubkey_authentication &&
1231 (!pubkey_auth_attempt || allowed != 1))
1232 auth_clear_options();
1233 break;
1234 case MM_HOSTKEY:
1235 allowed = options.hostbased_authentication &&
1236 match_pattern_list(sshkey_ssh_name(key),
1237 options.hostbased_key_types, 0) == 1 &&
1238 hostbased_key_allowed(authctxt->pw,
1239 cuser, chost, key);
1240 pubkey_auth_info(authctxt, key,
1241 "client user \"%.100s\", client host \"%.100s\"",
1242 cuser, chost);
1243 auth_method = "hostbased";
1244 break;
1245 #ifdef WITH_SSH1
1246 case MM_RSAHOSTKEY:
1247 key->type = KEY_RSA1; /* XXX */
1248 allowed = options.rhosts_rsa_authentication &&
1249 auth_rhosts_rsa_key_allowed(authctxt->pw,
1250 cuser, chost, key);
1251 if (options.rhosts_rsa_authentication && allowed != 1)
1252 auth_clear_options();
1253 auth_method = "rsa";
1254 break;
1255 #endif
1256 default:
1257 fatal("%s: unknown key type %d", __func__, type);
1258 break;
1259 }
1260 }
1261
1262 debug3("%s: key %p is %s",
1263 __func__, key, allowed ? "allowed" : "not allowed");
1264
1265 if (key != NULL)
1266 key_free(key);
1267
1268 /* clear temporarily storage (used by verify) */
1269 monitor_reset_key_state();
1270
1271 if (allowed) {
1272 /* Save temporarily for comparison in verify */
1273 key_blob = blob;
1274 key_bloblen = bloblen;
1275 key_blobtype = type;
1276 hostbased_cuser = cuser;
1277 hostbased_chost = chost;
1278 } else {
1279 /* Log failed attempt */
1280 auth_log(authctxt, 0, 0, auth_method, NULL);
1281 free(blob);
1282 free(cuser);
1283 free(chost);
1284 }
1285
1286 buffer_clear(m);
1287 buffer_put_int(m, allowed);
1288 buffer_put_int(m, forced_command != NULL);
1289
1290 mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m);
1291
1292 if (type == MM_RSAHOSTKEY)
1293 monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed);
1294
1295 return (0);
1296 }
1297
1298 static int
monitor_valid_userblob(u_char * data,u_int datalen)1299 monitor_valid_userblob(u_char *data, u_int datalen)
1300 {
1301 Buffer b;
1302 u_char *p;
1303 char *userstyle, *cp;
1304 u_int len;
1305 int fail = 0;
1306
1307 buffer_init(&b);
1308 buffer_append(&b, data, datalen);
1309
1310 if (datafellows & SSH_OLD_SESSIONID) {
1311 p = buffer_ptr(&b);
1312 len = buffer_len(&b);
1313 if ((session_id2 == NULL) ||
1314 (len < session_id2_len) ||
1315 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0))
1316 fail++;
1317 buffer_consume(&b, session_id2_len);
1318 } else {
1319 p = buffer_get_string(&b, &len);
1320 if ((session_id2 == NULL) ||
1321 (len != session_id2_len) ||
1322 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0))
1323 fail++;
1324 free(p);
1325 }
1326 if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST)
1327 fail++;
1328 cp = buffer_get_cstring(&b, NULL);
1329 xasprintf(&userstyle, "%s%s%s", authctxt->user,
1330 authctxt->style ? ":" : "",
1331 authctxt->style ? authctxt->style : "");
1332 if (strcmp(userstyle, cp) != 0) {
1333 logit("wrong user name passed to monitor: "
1334 "expected %s != %.100s", userstyle, cp);
1335 fail++;
1336 }
1337 free(userstyle);
1338 free(cp);
1339 buffer_skip_string(&b);
1340 if (datafellows & SSH_BUG_PKAUTH) {
1341 if (!buffer_get_char(&b))
1342 fail++;
1343 } else {
1344 cp = buffer_get_cstring(&b, NULL);
1345 if (strcmp("publickey", cp) != 0)
1346 fail++;
1347 free(cp);
1348 if (!buffer_get_char(&b))
1349 fail++;
1350 buffer_skip_string(&b);
1351 }
1352 buffer_skip_string(&b);
1353 if (buffer_len(&b) != 0)
1354 fail++;
1355 buffer_free(&b);
1356 return (fail == 0);
1357 }
1358
1359 static int
monitor_valid_hostbasedblob(u_char * data,u_int datalen,char * cuser,char * chost)1360 monitor_valid_hostbasedblob(u_char *data, u_int datalen, char *cuser,
1361 char *chost)
1362 {
1363 Buffer b;
1364 char *p, *userstyle;
1365 u_int len;
1366 int fail = 0;
1367
1368 buffer_init(&b);
1369 buffer_append(&b, data, datalen);
1370
1371 p = buffer_get_string(&b, &len);
1372 if ((session_id2 == NULL) ||
1373 (len != session_id2_len) ||
1374 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0))
1375 fail++;
1376 free(p);
1377
1378 if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST)
1379 fail++;
1380 p = buffer_get_cstring(&b, NULL);
1381 xasprintf(&userstyle, "%s%s%s", authctxt->user,
1382 authctxt->style ? ":" : "",
1383 authctxt->style ? authctxt->style : "");
1384 if (strcmp(userstyle, p) != 0) {
1385 logit("wrong user name passed to monitor: expected %s != %.100s",
1386 userstyle, p);
1387 fail++;
1388 }
1389 free(userstyle);
1390 free(p);
1391 buffer_skip_string(&b); /* service */
1392 p = buffer_get_cstring(&b, NULL);
1393 if (strcmp(p, "hostbased") != 0)
1394 fail++;
1395 free(p);
1396 buffer_skip_string(&b); /* pkalg */
1397 buffer_skip_string(&b); /* pkblob */
1398
1399 /* verify client host, strip trailing dot if necessary */
1400 p = buffer_get_string(&b, NULL);
1401 if (((len = strlen(p)) > 0) && p[len - 1] == '.')
1402 p[len - 1] = '\0';
1403 if (strcmp(p, chost) != 0)
1404 fail++;
1405 free(p);
1406
1407 /* verify client user */
1408 p = buffer_get_string(&b, NULL);
1409 if (strcmp(p, cuser) != 0)
1410 fail++;
1411 free(p);
1412
1413 if (buffer_len(&b) != 0)
1414 fail++;
1415 buffer_free(&b);
1416 return (fail == 0);
1417 }
1418
1419 int
mm_answer_keyverify(int sock,Buffer * m)1420 mm_answer_keyverify(int sock, Buffer *m)
1421 {
1422 Key *key;
1423 u_char *signature, *data, *blob;
1424 u_int signaturelen, datalen, bloblen;
1425 int verified = 0;
1426 int valid_data = 0;
1427
1428 blob = buffer_get_string(m, &bloblen);
1429 signature = buffer_get_string(m, &signaturelen);
1430 data = buffer_get_string(m, &datalen);
1431
1432 if (hostbased_cuser == NULL || hostbased_chost == NULL ||
1433 !monitor_allowed_key(blob, bloblen))
1434 fatal("%s: bad key, not previously allowed", __func__);
1435
1436 key = key_from_blob(blob, bloblen);
1437 if (key == NULL)
1438 fatal("%s: bad public key blob", __func__);
1439
1440 switch (key_blobtype) {
1441 case MM_USERKEY:
1442 valid_data = monitor_valid_userblob(data, datalen);
1443 break;
1444 case MM_HOSTKEY:
1445 valid_data = monitor_valid_hostbasedblob(data, datalen,
1446 hostbased_cuser, hostbased_chost);
1447 break;
1448 default:
1449 valid_data = 0;
1450 break;
1451 }
1452 if (!valid_data)
1453 fatal("%s: bad signature data blob", __func__);
1454
1455 verified = key_verify(key, signature, signaturelen, data, datalen);
1456 debug3("%s: key %p signature %s",
1457 __func__, key, (verified == 1) ? "verified" : "unverified");
1458
1459 /* If auth was successful then record key to ensure it isn't reused */
1460 if (verified == 1 && key_blobtype == MM_USERKEY)
1461 auth2_record_userkey(authctxt, key);
1462 else
1463 key_free(key);
1464
1465 free(blob);
1466 free(signature);
1467 free(data);
1468
1469 auth_method = key_blobtype == MM_USERKEY ? "publickey" : "hostbased";
1470
1471 monitor_reset_key_state();
1472
1473 buffer_clear(m);
1474 buffer_put_int(m, verified);
1475 mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m);
1476
1477 return (verified == 1);
1478 }
1479
1480 static void
mm_record_login(Session * s,struct passwd * pw)1481 mm_record_login(Session *s, struct passwd *pw)
1482 {
1483 struct ssh *ssh = active_state; /* XXX */
1484 socklen_t fromlen;
1485 struct sockaddr_storage from;
1486
1487 if (options.use_login)
1488 return;
1489
1490 /*
1491 * Get IP address of client. If the connection is not a socket, let
1492 * the address be 0.0.0.0.
1493 */
1494 memset(&from, 0, sizeof(from));
1495 fromlen = sizeof(from);
1496 if (packet_connection_is_on_socket()) {
1497 if (getpeername(packet_get_connection_in(),
1498 (struct sockaddr *)&from, &fromlen) < 0) {
1499 debug("getpeername: %.100s", strerror(errno));
1500 cleanup_exit(255);
1501 }
1502 }
1503 /* Record that there was a login on that tty from the remote host. */
1504 record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid,
1505 session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns),
1506 (struct sockaddr *)&from, fromlen);
1507 }
1508
1509 static void
mm_session_close(Session * s)1510 mm_session_close(Session *s)
1511 {
1512 debug3("%s: session %d pid %ld", __func__, s->self, (long)s->pid);
1513 if (s->ttyfd != -1) {
1514 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ptyfd);
1515 session_pty_cleanup2(s);
1516 }
1517 session_unused(s->self);
1518 }
1519
1520 int
mm_answer_pty(int sock,Buffer * m)1521 mm_answer_pty(int sock, Buffer *m)
1522 {
1523 extern struct monitor *pmonitor;
1524 Session *s;
1525 int res, fd0;
1526
1527 debug3("%s entering", __func__);
1528
1529 buffer_clear(m);
1530 s = session_new();
1531 if (s == NULL)
1532 goto error;
1533 s->authctxt = authctxt;
1534 s->pw = authctxt->pw;
1535 s->pid = pmonitor->m_pid;
1536 res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty));
1537 if (res == 0)
1538 goto error;
1539 pty_setowner(authctxt->pw, s->tty);
1540
1541 buffer_put_int(m, 1);
1542 buffer_put_cstring(m, s->tty);
1543
1544 /* We need to trick ttyslot */
1545 if (dup2(s->ttyfd, 0) == -1)
1546 fatal("%s: dup2", __func__);
1547
1548 mm_record_login(s, authctxt->pw);
1549
1550 /* Now we can close the file descriptor again */
1551 close(0);
1552
1553 /* send messages generated by record_login */
1554 buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg));
1555 buffer_clear(&loginmsg);
1556
1557 mm_request_send(sock, MONITOR_ANS_PTY, m);
1558
1559 if (mm_send_fd(sock, s->ptyfd) == -1 ||
1560 mm_send_fd(sock, s->ttyfd) == -1)
1561 fatal("%s: send fds failed", __func__);
1562
1563 /* make sure nothing uses fd 0 */
1564 if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) < 0)
1565 fatal("%s: open(/dev/null): %s", __func__, strerror(errno));
1566 if (fd0 != 0)
1567 error("%s: fd0 %d != 0", __func__, fd0);
1568
1569 /* slave is not needed */
1570 close(s->ttyfd);
1571 s->ttyfd = s->ptyfd;
1572 /* no need to dup() because nobody closes ptyfd */
1573 s->ptymaster = s->ptyfd;
1574
1575 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ttyfd);
1576
1577 return (0);
1578
1579 error:
1580 if (s != NULL)
1581 mm_session_close(s);
1582 buffer_put_int(m, 0);
1583 mm_request_send(sock, MONITOR_ANS_PTY, m);
1584 return (0);
1585 }
1586
1587 int
mm_answer_pty_cleanup(int sock,Buffer * m)1588 mm_answer_pty_cleanup(int sock, Buffer *m)
1589 {
1590 Session *s;
1591 char *tty;
1592
1593 debug3("%s entering", __func__);
1594
1595 tty = buffer_get_string(m, NULL);
1596 if ((s = session_by_tty(tty)) != NULL)
1597 mm_session_close(s);
1598 buffer_clear(m);
1599 free(tty);
1600 return (0);
1601 }
1602
1603 #ifdef WITH_SSH1
1604 int
mm_answer_sesskey(int sock,Buffer * m)1605 mm_answer_sesskey(int sock, Buffer *m)
1606 {
1607 BIGNUM *p;
1608 int rsafail;
1609
1610 /* Turn off permissions */
1611 monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 0);
1612
1613 if ((p = BN_new()) == NULL)
1614 fatal("%s: BN_new", __func__);
1615
1616 buffer_get_bignum2(m, p);
1617
1618 rsafail = ssh1_session_key(p);
1619
1620 buffer_clear(m);
1621 buffer_put_int(m, rsafail);
1622 buffer_put_bignum2(m, p);
1623
1624 BN_clear_free(p);
1625
1626 mm_request_send(sock, MONITOR_ANS_SESSKEY, m);
1627
1628 /* Turn on permissions for sessid passing */
1629 monitor_permit(mon_dispatch, MONITOR_REQ_SESSID, 1);
1630
1631 return (0);
1632 }
1633
1634 int
mm_answer_sessid(int sock,Buffer * m)1635 mm_answer_sessid(int sock, Buffer *m)
1636 {
1637 int i;
1638
1639 debug3("%s entering", __func__);
1640
1641 if (buffer_len(m) != 16)
1642 fatal("%s: bad ssh1 session id", __func__);
1643 for (i = 0; i < 16; i++)
1644 session_id[i] = buffer_get_char(m);
1645
1646 /* Turn on permissions for getpwnam */
1647 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1);
1648
1649 return (0);
1650 }
1651
1652 int
mm_answer_rsa_keyallowed(int sock,Buffer * m)1653 mm_answer_rsa_keyallowed(int sock, Buffer *m)
1654 {
1655 BIGNUM *client_n;
1656 Key *key = NULL;
1657 u_char *blob = NULL;
1658 u_int blen = 0;
1659 int allowed = 0;
1660
1661 debug3("%s entering", __func__);
1662
1663 auth_method = "rsa";
1664 if (options.rsa_authentication && authctxt->valid) {
1665 if ((client_n = BN_new()) == NULL)
1666 fatal("%s: BN_new", __func__);
1667 buffer_get_bignum2(m, client_n);
1668 allowed = auth_rsa_key_allowed(authctxt->pw, client_n, &key);
1669 BN_clear_free(client_n);
1670 }
1671 buffer_clear(m);
1672 buffer_put_int(m, allowed);
1673 buffer_put_int(m, forced_command != NULL);
1674
1675 /* clear temporarily storage (used by generate challenge) */
1676 monitor_reset_key_state();
1677
1678 if (allowed && key != NULL) {
1679 key->type = KEY_RSA; /* cheat for key_to_blob */
1680 if (key_to_blob(key, &blob, &blen) == 0)
1681 fatal("%s: key_to_blob failed", __func__);
1682 buffer_put_string(m, blob, blen);
1683
1684 /* Save temporarily for comparison in verify */
1685 key_blob = blob;
1686 key_bloblen = blen;
1687 key_blobtype = MM_RSAUSERKEY;
1688 }
1689 if (key != NULL)
1690 key_free(key);
1691
1692 mm_request_send(sock, MONITOR_ANS_RSAKEYALLOWED, m);
1693
1694 monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed);
1695 monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 0);
1696 return (0);
1697 }
1698
1699 int
mm_answer_rsa_challenge(int sock,Buffer * m)1700 mm_answer_rsa_challenge(int sock, Buffer *m)
1701 {
1702 Key *key = NULL;
1703 u_char *blob;
1704 u_int blen;
1705
1706 debug3("%s entering", __func__);
1707
1708 if (!authctxt->valid)
1709 fatal("%s: authctxt not valid", __func__);
1710 blob = buffer_get_string(m, &blen);
1711 if (!monitor_allowed_key(blob, blen))
1712 fatal("%s: bad key, not previously allowed", __func__);
1713 if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY)
1714 fatal("%s: key type mismatch", __func__);
1715 if ((key = key_from_blob(blob, blen)) == NULL)
1716 fatal("%s: received bad key", __func__);
1717 if (key->type != KEY_RSA)
1718 fatal("%s: received bad key type %d", __func__, key->type);
1719 key->type = KEY_RSA1;
1720 if (ssh1_challenge)
1721 BN_clear_free(ssh1_challenge);
1722 ssh1_challenge = auth_rsa_generate_challenge(key);
1723
1724 buffer_clear(m);
1725 buffer_put_bignum2(m, ssh1_challenge);
1726
1727 debug3("%s sending reply", __func__);
1728 mm_request_send(sock, MONITOR_ANS_RSACHALLENGE, m);
1729
1730 monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 1);
1731
1732 free(blob);
1733 key_free(key);
1734 return (0);
1735 }
1736
1737 int
mm_answer_rsa_response(int sock,Buffer * m)1738 mm_answer_rsa_response(int sock, Buffer *m)
1739 {
1740 Key *key = NULL;
1741 u_char *blob, *response;
1742 u_int blen, len;
1743 int success;
1744
1745 debug3("%s entering", __func__);
1746
1747 if (!authctxt->valid)
1748 fatal("%s: authctxt not valid", __func__);
1749 if (ssh1_challenge == NULL)
1750 fatal("%s: no ssh1_challenge", __func__);
1751
1752 blob = buffer_get_string(m, &blen);
1753 if (!monitor_allowed_key(blob, blen))
1754 fatal("%s: bad key, not previously allowed", __func__);
1755 if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY)
1756 fatal("%s: key type mismatch: %d", __func__, key_blobtype);
1757 if ((key = key_from_blob(blob, blen)) == NULL)
1758 fatal("%s: received bad key", __func__);
1759 response = buffer_get_string(m, &len);
1760 if (len != 16)
1761 fatal("%s: received bad response to challenge", __func__);
1762 success = auth_rsa_verify_response(key, ssh1_challenge, response);
1763
1764 free(blob);
1765 key_free(key);
1766 free(response);
1767
1768 auth_method = key_blobtype == MM_RSAUSERKEY ? "rsa" : "rhosts-rsa";
1769
1770 /* reset state */
1771 BN_clear_free(ssh1_challenge);
1772 ssh1_challenge = NULL;
1773 monitor_reset_key_state();
1774
1775 buffer_clear(m);
1776 buffer_put_int(m, success);
1777 mm_request_send(sock, MONITOR_ANS_RSARESPONSE, m);
1778
1779 return (success);
1780 }
1781 #endif
1782
1783 int
mm_answer_term(int sock,Buffer * req)1784 mm_answer_term(int sock, Buffer *req)
1785 {
1786 extern struct monitor *pmonitor;
1787 int res, status;
1788
1789 debug3("%s: tearing down sessions", __func__);
1790
1791 /* The child is terminating */
1792 session_destroy_all(&mm_session_close);
1793
1794 #ifdef USE_PAM
1795 if (options.use_pam)
1796 sshpam_cleanup();
1797 #endif
1798
1799 while (waitpid(pmonitor->m_pid, &status, 0) == -1)
1800 if (errno != EINTR)
1801 exit(1);
1802
1803 res = WIFEXITED(status) ? WEXITSTATUS(status) : 1;
1804
1805 /* Terminate process */
1806 exit(res);
1807 }
1808
1809 #ifdef SSH_AUDIT_EVENTS
1810 /* Report that an audit event occurred */
1811 int
mm_answer_audit_event(int socket,Buffer * m)1812 mm_answer_audit_event(int socket, Buffer *m)
1813 {
1814 ssh_audit_event_t event;
1815
1816 debug3("%s entering", __func__);
1817
1818 event = buffer_get_int(m);
1819 switch(event) {
1820 case SSH_AUTH_FAIL_PUBKEY:
1821 case SSH_AUTH_FAIL_HOSTBASED:
1822 case SSH_AUTH_FAIL_GSSAPI:
1823 case SSH_LOGIN_EXCEED_MAXTRIES:
1824 case SSH_LOGIN_ROOT_DENIED:
1825 case SSH_CONNECTION_CLOSE:
1826 case SSH_INVALID_USER:
1827 audit_event(event);
1828 break;
1829 default:
1830 fatal("Audit event type %d not permitted", event);
1831 }
1832
1833 return (0);
1834 }
1835
1836 int
mm_answer_audit_command(int socket,Buffer * m)1837 mm_answer_audit_command(int socket, Buffer *m)
1838 {
1839 u_int len;
1840 char *cmd;
1841
1842 debug3("%s entering", __func__);
1843 cmd = buffer_get_string(m, &len);
1844 /* sanity check command, if so how? */
1845 audit_run_command(cmd);
1846 free(cmd);
1847 return (0);
1848 }
1849 #endif /* SSH_AUDIT_EVENTS */
1850
1851 void
monitor_apply_keystate(struct monitor * pmonitor)1852 monitor_apply_keystate(struct monitor *pmonitor)
1853 {
1854 struct ssh *ssh = active_state; /* XXX */
1855 struct kex *kex;
1856 int r;
1857
1858 debug3("%s: packet_set_state", __func__);
1859 if ((r = ssh_packet_set_state(ssh, child_state)) != 0)
1860 fatal("%s: packet_set_state: %s", __func__, ssh_err(r));
1861 sshbuf_free(child_state);
1862 child_state = NULL;
1863
1864 if ((kex = ssh->kex) != NULL) {
1865 /* XXX set callbacks */
1866 #ifdef WITH_OPENSSL
1867 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
1868 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
1869 kex->kex[KEX_DH_GRP14_SHA256] = kexdh_server;
1870 kex->kex[KEX_DH_GRP16_SHA512] = kexdh_server;
1871 kex->kex[KEX_DH_GRP18_SHA512] = kexdh_server;
1872 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
1873 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
1874 # ifdef OPENSSL_HAS_ECC
1875 kex->kex[KEX_ECDH_SHA2] = kexecdh_server;
1876 # endif
1877 #endif /* WITH_OPENSSL */
1878 kex->kex[KEX_C25519_SHA256] = kexc25519_server;
1879 kex->load_host_public_key=&get_hostkey_public_by_type;
1880 kex->load_host_private_key=&get_hostkey_private_by_type;
1881 kex->host_key_index=&get_hostkey_index;
1882 kex->sign = sshd_hostkey_sign;
1883 }
1884
1885 /* Update with new address */
1886 if (options.compression) {
1887 ssh_packet_set_compress_hooks(ssh, pmonitor->m_zlib,
1888 (ssh_packet_comp_alloc_func *)mm_zalloc,
1889 (ssh_packet_comp_free_func *)mm_zfree);
1890 }
1891 }
1892
1893 /* This function requries careful sanity checking */
1894
1895 void
mm_get_keystate(struct monitor * pmonitor)1896 mm_get_keystate(struct monitor *pmonitor)
1897 {
1898 debug3("%s: Waiting for new keys", __func__);
1899
1900 if ((child_state = sshbuf_new()) == NULL)
1901 fatal("%s: sshbuf_new failed", __func__);
1902 mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT,
1903 child_state);
1904 debug3("%s: GOT new keys", __func__);
1905 }
1906
1907
1908 /* XXX */
1909
1910 #define FD_CLOSEONEXEC(x) do { \
1911 if (fcntl(x, F_SETFD, FD_CLOEXEC) == -1) \
1912 fatal("fcntl(%d, F_SETFD)", x); \
1913 } while (0)
1914
1915 static void
monitor_openfds(struct monitor * mon,int do_logfds)1916 monitor_openfds(struct monitor *mon, int do_logfds)
1917 {
1918 int pair[2];
1919
1920 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1)
1921 fatal("%s: socketpair: %s", __func__, strerror(errno));
1922 FD_CLOSEONEXEC(pair[0]);
1923 FD_CLOSEONEXEC(pair[1]);
1924 mon->m_recvfd = pair[0];
1925 mon->m_sendfd = pair[1];
1926
1927 if (do_logfds) {
1928 if (pipe(pair) == -1)
1929 fatal("%s: pipe: %s", __func__, strerror(errno));
1930 FD_CLOSEONEXEC(pair[0]);
1931 FD_CLOSEONEXEC(pair[1]);
1932 mon->m_log_recvfd = pair[0];
1933 mon->m_log_sendfd = pair[1];
1934 } else
1935 mon->m_log_recvfd = mon->m_log_sendfd = -1;
1936 }
1937
1938 #define MM_MEMSIZE 65536
1939
1940 struct monitor *
monitor_init(void)1941 monitor_init(void)
1942 {
1943 struct ssh *ssh = active_state; /* XXX */
1944 struct monitor *mon;
1945
1946 mon = xcalloc(1, sizeof(*mon));
1947
1948 monitor_openfds(mon, 1);
1949
1950 /* Used to share zlib space across processes */
1951 if (options.compression) {
1952 mon->m_zback = mm_create(NULL, MM_MEMSIZE);
1953 mon->m_zlib = mm_create(mon->m_zback, 20 * MM_MEMSIZE);
1954
1955 /* Compression needs to share state across borders */
1956 ssh_packet_set_compress_hooks(ssh, mon->m_zlib,
1957 (ssh_packet_comp_alloc_func *)mm_zalloc,
1958 (ssh_packet_comp_free_func *)mm_zfree);
1959 }
1960
1961 return mon;
1962 }
1963
1964 void
monitor_reinit(struct monitor * mon)1965 monitor_reinit(struct monitor *mon)
1966 {
1967 monitor_openfds(mon, 0);
1968 }
1969
1970 #ifdef GSSAPI
1971 int
mm_answer_gss_setup_ctx(int sock,Buffer * m)1972 mm_answer_gss_setup_ctx(int sock, Buffer *m)
1973 {
1974 gss_OID_desc goid;
1975 OM_uint32 major;
1976 u_int len;
1977
1978 goid.elements = buffer_get_string(m, &len);
1979 goid.length = len;
1980
1981 major = ssh_gssapi_server_ctx(&gsscontext, &goid);
1982
1983 free(goid.elements);
1984
1985 buffer_clear(m);
1986 buffer_put_int(m, major);
1987
1988 mm_request_send(sock, MONITOR_ANS_GSSSETUP, m);
1989
1990 /* Now we have a context, enable the step */
1991 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1);
1992
1993 return (0);
1994 }
1995
1996 int
mm_answer_gss_accept_ctx(int sock,Buffer * m)1997 mm_answer_gss_accept_ctx(int sock, Buffer *m)
1998 {
1999 gss_buffer_desc in;
2000 gss_buffer_desc out = GSS_C_EMPTY_BUFFER;
2001 OM_uint32 major, minor;
2002 OM_uint32 flags = 0; /* GSI needs this */
2003 u_int len;
2004
2005 in.value = buffer_get_string(m, &len);
2006 in.length = len;
2007 major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags);
2008 free(in.value);
2009
2010 buffer_clear(m);
2011 buffer_put_int(m, major);
2012 buffer_put_string(m, out.value, out.length);
2013 buffer_put_int(m, flags);
2014 mm_request_send(sock, MONITOR_ANS_GSSSTEP, m);
2015
2016 gss_release_buffer(&minor, &out);
2017
2018 if (major == GSS_S_COMPLETE) {
2019 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0);
2020 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
2021 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1);
2022 }
2023 return (0);
2024 }
2025
2026 int
mm_answer_gss_checkmic(int sock,Buffer * m)2027 mm_answer_gss_checkmic(int sock, Buffer *m)
2028 {
2029 gss_buffer_desc gssbuf, mic;
2030 OM_uint32 ret;
2031 u_int len;
2032
2033 gssbuf.value = buffer_get_string(m, &len);
2034 gssbuf.length = len;
2035 mic.value = buffer_get_string(m, &len);
2036 mic.length = len;
2037
2038 ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic);
2039
2040 free(gssbuf.value);
2041 free(mic.value);
2042
2043 buffer_clear(m);
2044 buffer_put_int(m, ret);
2045
2046 mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m);
2047
2048 if (!GSS_ERROR(ret))
2049 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
2050
2051 return (0);
2052 }
2053
2054 int
mm_answer_gss_userok(int sock,Buffer * m)2055 mm_answer_gss_userok(int sock, Buffer *m)
2056 {
2057 int authenticated;
2058
2059 authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user);
2060
2061 buffer_clear(m);
2062 buffer_put_int(m, authenticated);
2063
2064 debug3("%s: sending result %d", __func__, authenticated);
2065 mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m);
2066
2067 auth_method = "gssapi-with-mic";
2068
2069 /* Monitor loop will terminate if authenticated */
2070 return (authenticated);
2071 }
2072 #endif /* GSSAPI */
2073
2074