1 /* $OpenBSD: monitor.c,v 1.240 2024/06/06 17:15:25 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 <sys/wait.h>
33
34 #include <errno.h>
35 #include <fcntl.h>
36 #include <limits.h>
37 #ifdef HAVE_PATHS_H
38 #include <paths.h>
39 #endif
40 #include <pwd.h>
41 #include <signal.h>
42 #ifdef HAVE_STDINT_H
43 # include <stdint.h>
44 #endif
45 #include <stdlib.h>
46 #include <string.h>
47 #include <stdarg.h>
48 #include <stdio.h>
49 #include <unistd.h>
50 #ifdef HAVE_POLL_H
51 #include <poll.h>
52 #else
53 # ifdef HAVE_SYS_POLL_H
54 # include <sys/poll.h>
55 # endif
56 #endif
57
58 #ifdef WITH_OPENSSL
59 #include <openssl/dh.h>
60 #endif
61
62 #include "openbsd-compat/sys-tree.h"
63 #include "openbsd-compat/sys-queue.h"
64 #include "openbsd-compat/openssl-compat.h"
65
66 #include "atomicio.h"
67 #include "xmalloc.h"
68 #include "ssh.h"
69 #include "sshkey.h"
70 #include "sshbuf.h"
71 #include "hostfile.h"
72 #include "auth.h"
73 #include "cipher.h"
74 #include "kex.h"
75 #include "dh.h"
76 #include "auth-pam.h"
77 #include "packet.h"
78 #include "auth-options.h"
79 #include "sshpty.h"
80 #include "channels.h"
81 #include "session.h"
82 #include "sshlogin.h"
83 #include "canohost.h"
84 #include "log.h"
85 #include "misc.h"
86 #include "servconf.h"
87 #include "monitor.h"
88 #ifdef GSSAPI
89 #include "ssh-gss.h"
90 #endif
91 #include "monitor_wrap.h"
92 #include "monitor_fdpass.h"
93 #include "compat.h"
94 #include "ssh2.h"
95 #include "authfd.h"
96 #include "match.h"
97 #include "ssherr.h"
98 #include "sk-api.h"
99
100 #ifdef GSSAPI
101 static Gssctxt *gsscontext = NULL;
102 #endif
103
104 /* Imports */
105 extern ServerOptions options;
106 extern u_int utmp_len;
107 extern struct sshbuf *loginmsg;
108 extern struct sshauthopt *auth_opts; /* XXX move to permanent ssh->authctxt? */
109
110 /* State exported from the child */
111 static struct sshbuf *child_state;
112
113 /* Functions on the monitor that answer unprivileged requests */
114
115 int mm_answer_moduli(struct ssh *, int, struct sshbuf *);
116 int mm_answer_sign(struct ssh *, int, struct sshbuf *);
117 int mm_answer_pwnamallow(struct ssh *, int, struct sshbuf *);
118 int mm_answer_auth2_read_banner(struct ssh *, int, struct sshbuf *);
119 int mm_answer_authserv(struct ssh *, int, struct sshbuf *);
120 int mm_answer_authpassword(struct ssh *, int, struct sshbuf *);
121 int mm_answer_bsdauthquery(struct ssh *, int, struct sshbuf *);
122 int mm_answer_bsdauthrespond(struct ssh *, int, struct sshbuf *);
123 int mm_answer_keyallowed(struct ssh *, int, struct sshbuf *);
124 int mm_answer_keyverify(struct ssh *, int, struct sshbuf *);
125 int mm_answer_pty(struct ssh *, int, struct sshbuf *);
126 int mm_answer_pty_cleanup(struct ssh *, int, struct sshbuf *);
127 int mm_answer_term(struct ssh *, int, struct sshbuf *);
128
129 #ifdef USE_PAM
130 int mm_answer_pam_start(struct ssh *, int, struct sshbuf *);
131 int mm_answer_pam_account(struct ssh *, int, struct sshbuf *);
132 int mm_answer_pam_init_ctx(struct ssh *, int, struct sshbuf *);
133 int mm_answer_pam_query(struct ssh *, int, struct sshbuf *);
134 int mm_answer_pam_respond(struct ssh *, int, struct sshbuf *);
135 int mm_answer_pam_free_ctx(struct ssh *, int, struct sshbuf *);
136 #endif
137
138 #ifdef GSSAPI
139 int mm_answer_gss_setup_ctx(struct ssh *, int, struct sshbuf *);
140 int mm_answer_gss_accept_ctx(struct ssh *, int, struct sshbuf *);
141 int mm_answer_gss_userok(struct ssh *, int, struct sshbuf *);
142 int mm_answer_gss_checkmic(struct ssh *, int, struct sshbuf *);
143 #endif
144
145 #ifdef SSH_AUDIT_EVENTS
146 int mm_answer_audit_event(struct ssh *, int, struct sshbuf *);
147 int mm_answer_audit_command(struct ssh *, int, struct sshbuf *);
148 #endif
149
150 static Authctxt *authctxt;
151
152 /* local state for key verify */
153 static u_char *key_blob = NULL;
154 static size_t key_bloblen = 0;
155 static u_int key_blobtype = MM_NOKEY;
156 static struct sshauthopt *key_opts = NULL;
157 static char *hostbased_cuser = NULL;
158 static char *hostbased_chost = NULL;
159 static char *auth_method = "unknown";
160 static char *auth_submethod = NULL;
161 static u_int session_id2_len = 0;
162 static u_char *session_id2 = NULL;
163 static pid_t monitor_child_pid;
164 int auth_attempted = 0;
165
166 struct mon_table {
167 enum monitor_reqtype type;
168 int flags;
169 int (*f)(struct ssh *, int, struct sshbuf *);
170 };
171
172 #define MON_ISAUTH 0x0004 /* Required for Authentication */
173 #define MON_AUTHDECIDE 0x0008 /* Decides Authentication */
174 #define MON_ONCE 0x0010 /* Disable after calling */
175 #define MON_ALOG 0x0020 /* Log auth attempt without authenticating */
176
177 #define MON_AUTH (MON_ISAUTH|MON_AUTHDECIDE)
178
179 #define MON_PERMIT 0x1000 /* Request is permitted */
180
181 static int monitor_read(struct ssh *, struct monitor *, struct mon_table *,
182 struct mon_table **);
183 static int monitor_read_log(struct monitor *);
184
185 struct mon_table mon_dispatch_proto20[] = {
186 #ifdef WITH_OPENSSL
187 {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli},
188 #endif
189 {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign},
190 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow},
191 {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv},
192 {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner},
193 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword},
194 #ifdef USE_PAM
195 {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start},
196 {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account},
197 {MONITOR_REQ_PAM_INIT_CTX, MON_ONCE, mm_answer_pam_init_ctx},
198 {MONITOR_REQ_PAM_QUERY, 0, mm_answer_pam_query},
199 {MONITOR_REQ_PAM_RESPOND, MON_ONCE, mm_answer_pam_respond},
200 {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx},
201 #endif
202 #ifdef SSH_AUDIT_EVENTS
203 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
204 #endif
205 #ifdef BSD_AUTH
206 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery},
207 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond},
208 #endif
209 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed},
210 {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify},
211 #ifdef GSSAPI
212 {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx},
213 {MONITOR_REQ_GSSSTEP, 0, mm_answer_gss_accept_ctx},
214 {MONITOR_REQ_GSSUSEROK, MON_ONCE|MON_AUTHDECIDE, mm_answer_gss_userok},
215 {MONITOR_REQ_GSSCHECKMIC, MON_ONCE, mm_answer_gss_checkmic},
216 #endif
217 {0, 0, NULL}
218 };
219
220 struct mon_table mon_dispatch_postauth20[] = {
221 #ifdef WITH_OPENSSL
222 {MONITOR_REQ_MODULI, 0, mm_answer_moduli},
223 #endif
224 {MONITOR_REQ_SIGN, 0, mm_answer_sign},
225 {MONITOR_REQ_PTY, 0, mm_answer_pty},
226 {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup},
227 {MONITOR_REQ_TERM, 0, mm_answer_term},
228 #ifdef SSH_AUDIT_EVENTS
229 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
230 {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT, mm_answer_audit_command},
231 #endif
232 {0, 0, NULL}
233 };
234
235 struct mon_table *mon_dispatch;
236
237 /* Specifies if a certain message is allowed at the moment */
238 static void
monitor_permit(struct mon_table * ent,enum monitor_reqtype type,int permit)239 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit)
240 {
241 while (ent->f != NULL) {
242 if (ent->type == type) {
243 ent->flags &= ~MON_PERMIT;
244 ent->flags |= permit ? MON_PERMIT : 0;
245 return;
246 }
247 ent++;
248 }
249 }
250
251 static void
monitor_permit_authentications(int permit)252 monitor_permit_authentications(int permit)
253 {
254 struct mon_table *ent = mon_dispatch;
255
256 while (ent->f != NULL) {
257 if (ent->flags & MON_AUTH) {
258 ent->flags &= ~MON_PERMIT;
259 ent->flags |= permit ? MON_PERMIT : 0;
260 }
261 ent++;
262 }
263 }
264
265 void
monitor_child_preauth(struct ssh * ssh,struct monitor * pmonitor)266 monitor_child_preauth(struct ssh *ssh, struct monitor *pmonitor)
267 {
268 struct mon_table *ent;
269 int authenticated = 0, partial = 0;
270
271 debug3("preauth child monitor started");
272
273 if (pmonitor->m_recvfd >= 0)
274 close(pmonitor->m_recvfd);
275 if (pmonitor->m_log_sendfd >= 0)
276 close(pmonitor->m_log_sendfd);
277 pmonitor->m_log_sendfd = pmonitor->m_recvfd = -1;
278
279 authctxt = (Authctxt *)ssh->authctxt;
280 memset(authctxt, 0, sizeof(*authctxt));
281 ssh->authctxt = authctxt;
282
283 authctxt->loginmsg = loginmsg;
284
285 mon_dispatch = mon_dispatch_proto20;
286 /* Permit requests for moduli and signatures */
287 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
288 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
289
290 /* The first few requests do not require asynchronous access */
291 while (!authenticated) {
292 partial = 0;
293 auth_method = "unknown";
294 auth_submethod = NULL;
295 auth2_authctxt_reset_info(authctxt);
296
297 authenticated = (monitor_read(ssh, pmonitor,
298 mon_dispatch, &ent) == 1);
299
300 /* Record that auth was attempted to set exit status later */
301 if ((ent->flags & MON_AUTH) != 0)
302 auth_attempted = 1;
303
304 /* Special handling for multiple required authentications */
305 if (options.num_auth_methods != 0) {
306 if (authenticated &&
307 !auth2_update_methods_lists(authctxt,
308 auth_method, auth_submethod)) {
309 debug3_f("method %s: partial", auth_method);
310 authenticated = 0;
311 partial = 1;
312 }
313 }
314
315 if (authenticated) {
316 if (!(ent->flags & MON_AUTHDECIDE))
317 fatal_f("unexpected authentication from %d",
318 ent->type);
319 if (authctxt->pw->pw_uid == 0 &&
320 !auth_root_allowed(ssh, auth_method))
321 authenticated = 0;
322 #ifdef USE_PAM
323 /* PAM needs to perform account checks after auth */
324 if (options.use_pam && authenticated) {
325 struct sshbuf *m;
326
327 if ((m = sshbuf_new()) == NULL)
328 fatal("%s: sshbuf_new failed",
329 __func__);
330 mm_request_receive_expect(pmonitor->m_sendfd,
331 MONITOR_REQ_PAM_ACCOUNT, m);
332 authenticated = mm_answer_pam_account(
333 ssh, pmonitor->m_sendfd, m);
334 sshbuf_free(m);
335 }
336 #endif
337 }
338 if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) {
339 auth_log(ssh, authenticated, partial,
340 auth_method, auth_submethod);
341 if (!partial && !authenticated)
342 authctxt->failures++;
343 if (authenticated || partial) {
344 auth2_update_session_info(authctxt,
345 auth_method, auth_submethod);
346 }
347 }
348 if (authctxt->failures > options.max_authtries) {
349 /* Shouldn't happen */
350 fatal_f("privsep child made too many authentication "
351 "attempts");
352 }
353 }
354
355 if (!authctxt->valid)
356 fatal_f("authenticated invalid user");
357 if (strcmp(auth_method, "unknown") == 0)
358 fatal_f("authentication method name unknown");
359
360 debug_f("user %s authenticated by privileged process", authctxt->user);
361 auth_attempted = 0;
362 ssh->authctxt = NULL;
363 ssh_packet_set_log_preamble(ssh, "user %s", authctxt->user);
364
365 mm_get_keystate(ssh, pmonitor);
366
367 /* Drain any buffered messages from the child */
368 while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0)
369 ;
370
371 if (pmonitor->m_recvfd >= 0)
372 close(pmonitor->m_recvfd);
373 if (pmonitor->m_log_sendfd >= 0)
374 close(pmonitor->m_log_sendfd);
375 pmonitor->m_sendfd = pmonitor->m_log_recvfd = -1;
376 }
377
378 static void
monitor_set_child_handler(pid_t pid)379 monitor_set_child_handler(pid_t pid)
380 {
381 monitor_child_pid = pid;
382 }
383
384 static void
monitor_child_handler(int sig)385 monitor_child_handler(int sig)
386 {
387 kill(monitor_child_pid, sig);
388 }
389
390 void
monitor_child_postauth(struct ssh * ssh,struct monitor * pmonitor)391 monitor_child_postauth(struct ssh *ssh, struct monitor *pmonitor)
392 {
393 close(pmonitor->m_recvfd);
394 pmonitor->m_recvfd = -1;
395
396 monitor_set_child_handler(pmonitor->m_pid);
397 ssh_signal(SIGHUP, &monitor_child_handler);
398 ssh_signal(SIGTERM, &monitor_child_handler);
399 ssh_signal(SIGINT, &monitor_child_handler);
400 #ifdef SIGXFSZ
401 ssh_signal(SIGXFSZ, SIG_IGN);
402 #endif
403
404 mon_dispatch = mon_dispatch_postauth20;
405
406 /* Permit requests for moduli and signatures */
407 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
408 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
409 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1);
410
411 if (auth_opts->permit_pty_flag) {
412 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1);
413 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1);
414 }
415
416 for (;;)
417 monitor_read(ssh, pmonitor, mon_dispatch, NULL);
418 }
419
420 static int
monitor_read_log(struct monitor * pmonitor)421 monitor_read_log(struct monitor *pmonitor)
422 {
423 struct sshbuf *logmsg;
424 u_int len, level, forced;
425 char *msg;
426 u_char *p;
427 int r;
428
429 if ((logmsg = sshbuf_new()) == NULL)
430 fatal_f("sshbuf_new");
431
432 /* Read length */
433 if ((r = sshbuf_reserve(logmsg, 4, &p)) != 0)
434 fatal_fr(r, "reserve len");
435 if (atomicio(read, pmonitor->m_log_recvfd, p, 4) != 4) {
436 if (errno == EPIPE) {
437 sshbuf_free(logmsg);
438 debug_f("child log fd closed");
439 close(pmonitor->m_log_recvfd);
440 pmonitor->m_log_recvfd = -1;
441 return -1;
442 }
443 fatal_f("log fd read: %s", strerror(errno));
444 }
445 if ((r = sshbuf_get_u32(logmsg, &len)) != 0)
446 fatal_fr(r, "parse len");
447 if (len <= 4 || len > 8192)
448 fatal_f("invalid log message length %u", len);
449
450 /* Read severity, message */
451 sshbuf_reset(logmsg);
452 if ((r = sshbuf_reserve(logmsg, len, &p)) != 0)
453 fatal_fr(r, "reserve msg");
454 if (atomicio(read, pmonitor->m_log_recvfd, p, len) != len)
455 fatal_f("log fd read: %s", strerror(errno));
456 if ((r = sshbuf_get_u32(logmsg, &level)) != 0 ||
457 (r = sshbuf_get_u32(logmsg, &forced)) != 0 ||
458 (r = sshbuf_get_cstring(logmsg, &msg, NULL)) != 0)
459 fatal_fr(r, "parse");
460
461 /* Log it */
462 if (log_level_name(level) == NULL)
463 fatal_f("invalid log level %u (corrupted message?)", level);
464 sshlogdirect(level, forced, "%s [preauth]", msg);
465
466 sshbuf_free(logmsg);
467 free(msg);
468
469 return 0;
470 }
471
472 static int
monitor_read(struct ssh * ssh,struct monitor * pmonitor,struct mon_table * ent,struct mon_table ** pent)473 monitor_read(struct ssh *ssh, struct monitor *pmonitor, struct mon_table *ent,
474 struct mon_table **pent)
475 {
476 struct sshbuf *m;
477 int r, ret;
478 u_char type;
479 struct pollfd pfd[2];
480
481 for (;;) {
482 memset(&pfd, 0, sizeof(pfd));
483 pfd[0].fd = pmonitor->m_sendfd;
484 pfd[0].events = POLLIN;
485 pfd[1].fd = pmonitor->m_log_recvfd;
486 pfd[1].events = pfd[1].fd == -1 ? 0 : POLLIN;
487 if (poll(pfd, pfd[1].fd == -1 ? 1 : 2, -1) == -1) {
488 if (errno == EINTR || errno == EAGAIN)
489 continue;
490 fatal_f("poll: %s", strerror(errno));
491 }
492 if (pfd[1].revents) {
493 /*
494 * Drain all log messages before processing next
495 * monitor request.
496 */
497 monitor_read_log(pmonitor);
498 continue;
499 }
500 if (pfd[0].revents)
501 break; /* Continues below */
502 }
503
504 if ((m = sshbuf_new()) == NULL)
505 fatal_f("sshbuf_new");
506
507 mm_request_receive(pmonitor->m_sendfd, m);
508 if ((r = sshbuf_get_u8(m, &type)) != 0)
509 fatal_fr(r, "parse type");
510
511 debug3_f("checking request %d", type);
512
513 while (ent->f != NULL) {
514 if (ent->type == type)
515 break;
516 ent++;
517 }
518
519 if (ent->f != NULL) {
520 if (!(ent->flags & MON_PERMIT))
521 fatal_f("unpermitted request %d", type);
522 ret = (*ent->f)(ssh, pmonitor->m_sendfd, m);
523 sshbuf_free(m);
524
525 /* The child may use this request only once, disable it */
526 if (ent->flags & MON_ONCE) {
527 debug2_f("%d used once, disabling now", type);
528 ent->flags &= ~MON_PERMIT;
529 }
530
531 if (pent != NULL)
532 *pent = ent;
533
534 return ret;
535 }
536
537 fatal_f("unsupported request: %d", type);
538
539 /* NOTREACHED */
540 return (-1);
541 }
542
543 /* allowed key state */
544 static int
monitor_allowed_key(const u_char * blob,u_int bloblen)545 monitor_allowed_key(const u_char *blob, u_int bloblen)
546 {
547 /* make sure key is allowed */
548 if (key_blob == NULL || key_bloblen != bloblen ||
549 timingsafe_bcmp(key_blob, blob, key_bloblen))
550 return (0);
551 return (1);
552 }
553
554 static void
monitor_reset_key_state(void)555 monitor_reset_key_state(void)
556 {
557 /* reset state */
558 free(key_blob);
559 free(hostbased_cuser);
560 free(hostbased_chost);
561 sshauthopt_free(key_opts);
562 key_blob = NULL;
563 key_bloblen = 0;
564 key_blobtype = MM_NOKEY;
565 key_opts = NULL;
566 hostbased_cuser = NULL;
567 hostbased_chost = NULL;
568 }
569
570 #ifdef WITH_OPENSSL
571 int
mm_answer_moduli(struct ssh * ssh,int sock,struct sshbuf * m)572 mm_answer_moduli(struct ssh *ssh, int sock, struct sshbuf *m)
573 {
574 DH *dh;
575 const BIGNUM *dh_p, *dh_g;
576 int r;
577 u_int min, want, max;
578
579 if ((r = sshbuf_get_u32(m, &min)) != 0 ||
580 (r = sshbuf_get_u32(m, &want)) != 0 ||
581 (r = sshbuf_get_u32(m, &max)) != 0)
582 fatal_fr(r, "parse");
583
584 debug3_f("got parameters: %d %d %d", min, want, max);
585 /* We need to check here, too, in case the child got corrupted */
586 if (max < min || want < min || max < want)
587 fatal_f("bad parameters: %d %d %d", min, want, max);
588
589 sshbuf_reset(m);
590
591 dh = choose_dh(min, want, max);
592 if (dh == NULL) {
593 if ((r = sshbuf_put_u8(m, 0)) != 0)
594 fatal_fr(r, "assemble empty");
595 return (0);
596 } else {
597 /* Send first bignum */
598 DH_get0_pqg(dh, &dh_p, NULL, &dh_g);
599 if ((r = sshbuf_put_u8(m, 1)) != 0 ||
600 (r = sshbuf_put_bignum2(m, dh_p)) != 0 ||
601 (r = sshbuf_put_bignum2(m, dh_g)) != 0)
602 fatal_fr(r, "assemble");
603
604 DH_free(dh);
605 }
606 mm_request_send(sock, MONITOR_ANS_MODULI, m);
607 return (0);
608 }
609 #endif
610
611 int
mm_answer_sign(struct ssh * ssh,int sock,struct sshbuf * m)612 mm_answer_sign(struct ssh *ssh, int sock, struct sshbuf *m)
613 {
614 extern int auth_sock; /* XXX move to state struct? */
615 struct sshkey *key;
616 struct sshbuf *sigbuf = NULL;
617 u_char *p = NULL, *signature = NULL;
618 char *alg = NULL;
619 size_t datlen, siglen, alglen;
620 int r, is_proof = 0;
621 u_int keyid, compat;
622 const char proof_req[] = "hostkeys-prove-00@openssh.com";
623
624 debug3_f("entering");
625
626 if ((r = sshbuf_get_u32(m, &keyid)) != 0 ||
627 (r = sshbuf_get_string(m, &p, &datlen)) != 0 ||
628 (r = sshbuf_get_cstring(m, &alg, &alglen)) != 0 ||
629 (r = sshbuf_get_u32(m, &compat)) != 0)
630 fatal_fr(r, "parse");
631 if (keyid > INT_MAX)
632 fatal_f("invalid key ID");
633
634 /*
635 * Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes),
636 * SHA384 (48 bytes) and SHA512 (64 bytes).
637 *
638 * Otherwise, verify the signature request is for a hostkey
639 * proof.
640 *
641 * XXX perform similar check for KEX signature requests too?
642 * it's not trivial, since what is signed is the hash, rather
643 * than the full kex structure...
644 */
645 if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64) {
646 /*
647 * Construct expected hostkey proof and compare it to what
648 * the client sent us.
649 */
650 if (session_id2_len == 0) /* hostkeys is never first */
651 fatal_f("bad data length: %zu", datlen);
652 if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL)
653 fatal_f("no hostkey for index %d", keyid);
654 if ((sigbuf = sshbuf_new()) == NULL)
655 fatal_f("sshbuf_new");
656 if ((r = sshbuf_put_cstring(sigbuf, proof_req)) != 0 ||
657 (r = sshbuf_put_string(sigbuf, session_id2,
658 session_id2_len)) != 0 ||
659 (r = sshkey_puts(key, sigbuf)) != 0)
660 fatal_fr(r, "assemble private key proof");
661 if (datlen != sshbuf_len(sigbuf) ||
662 memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0)
663 fatal_f("bad data length: %zu, hostkey proof len %zu",
664 datlen, sshbuf_len(sigbuf));
665 sshbuf_free(sigbuf);
666 is_proof = 1;
667 }
668
669 /* save session id, it will be passed on the first call */
670 if (session_id2_len == 0) {
671 session_id2_len = datlen;
672 session_id2 = xmalloc(session_id2_len);
673 memcpy(session_id2, p, session_id2_len);
674 }
675
676 if ((key = get_hostkey_by_index(keyid)) != NULL) {
677 if ((r = sshkey_sign(key, &signature, &siglen, p, datlen, alg,
678 options.sk_provider, NULL, compat)) != 0)
679 fatal_fr(r, "sign");
680 } else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL &&
681 auth_sock > 0) {
682 if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen,
683 p, datlen, alg, compat)) != 0)
684 fatal_fr(r, "agent sign");
685 } else
686 fatal_f("no hostkey from index %d", keyid);
687
688 debug3_f("%s %s signature len=%zu", alg,
689 is_proof ? "hostkey proof" : "KEX", siglen);
690
691 sshbuf_reset(m);
692 if ((r = sshbuf_put_string(m, signature, siglen)) != 0)
693 fatal_fr(r, "assemble");
694
695 free(alg);
696 free(p);
697 free(signature);
698
699 mm_request_send(sock, MONITOR_ANS_SIGN, m);
700
701 /* Turn on permissions for getpwnam */
702 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1);
703
704 return (0);
705 }
706
707 #define PUTPW(b, id) \
708 do { \
709 if ((r = sshbuf_put_string(b, \
710 &pwent->id, sizeof(pwent->id))) != 0) \
711 fatal_fr(r, "assemble %s", #id); \
712 } while (0)
713
714 void
mm_encode_server_options(struct sshbuf * m)715 mm_encode_server_options(struct sshbuf *m)
716 {
717 int r;
718 u_int i;
719
720 /* XXX this leaks raw pointers to the unpriv child processes */
721 if ((r = sshbuf_put_string(m, &options, sizeof(options))) != 0)
722 fatal_fr(r, "assemble options");
723
724 #define M_CP_STROPT(x) do { \
725 if (options.x != NULL && \
726 (r = sshbuf_put_cstring(m, options.x)) != 0) \
727 fatal_fr(r, "assemble %s", #x); \
728 } while (0)
729 #define M_CP_STRARRAYOPT(x, nx) do { \
730 for (i = 0; i < options.nx; i++) { \
731 if ((r = sshbuf_put_cstring(m, options.x[i])) != 0) \
732 fatal_fr(r, "assemble %s", #x); \
733 } \
734 } while (0)
735 /* See comment in servconf.h */
736 COPY_MATCH_STRING_OPTS();
737 #undef M_CP_STROPT
738 #undef M_CP_STRARRAYOPT
739 }
740
741 /* Retrieves the password entry and also checks if the user is permitted */
742 int
mm_answer_pwnamallow(struct ssh * ssh,int sock,struct sshbuf * m)743 mm_answer_pwnamallow(struct ssh *ssh, int sock, struct sshbuf *m)
744 {
745 struct passwd *pwent;
746 int r, allowed = 0;
747
748 debug3_f("entering");
749
750 if (authctxt->attempt++ != 0)
751 fatal_f("multiple attempts for getpwnam");
752
753 if ((r = sshbuf_get_cstring(m, &authctxt->user, NULL)) != 0)
754 fatal_fr(r, "parse");
755
756 pwent = getpwnamallow(ssh, authctxt->user);
757
758 setproctitle("%s [priv]", pwent ? authctxt->user : "unknown");
759
760 sshbuf_reset(m);
761
762 if (pwent == NULL) {
763 if ((r = sshbuf_put_u8(m, 0)) != 0)
764 fatal_fr(r, "assemble fakepw");
765 authctxt->pw = fakepw();
766 goto out;
767 }
768
769 allowed = 1;
770 authctxt->pw = pwent;
771 authctxt->valid = 1;
772
773 /* XXX send fake class/dir/shell, etc. */
774 if ((r = sshbuf_put_u8(m, 1)) != 0)
775 fatal_fr(r, "assemble ok");
776 PUTPW(m, pw_uid);
777 PUTPW(m, pw_gid);
778 #ifdef HAVE_STRUCT_PASSWD_PW_CHANGE
779 PUTPW(m, pw_change);
780 #endif
781 #ifdef HAVE_STRUCT_PASSWD_PW_EXPIRE
782 PUTPW(m, pw_expire);
783 #endif
784 if ((r = sshbuf_put_cstring(m, pwent->pw_name)) != 0 ||
785 (r = sshbuf_put_cstring(m, "*")) != 0 ||
786 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS
787 (r = sshbuf_put_cstring(m, pwent->pw_gecos)) != 0 ||
788 #endif
789 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS
790 (r = sshbuf_put_cstring(m, pwent->pw_class)) != 0 ||
791 #endif
792 (r = sshbuf_put_cstring(m, pwent->pw_dir)) != 0 ||
793 (r = sshbuf_put_cstring(m, pwent->pw_shell)) != 0)
794 fatal_fr(r, "assemble pw");
795
796 out:
797 ssh_packet_set_log_preamble(ssh, "%suser %s",
798 authctxt->valid ? "authenticating" : "invalid ", authctxt->user);
799
800 /* Send active options to unpriv */
801 mm_encode_server_options(m);
802
803 /* Create valid auth method lists */
804 if (auth2_setup_methods_lists(authctxt) != 0) {
805 /*
806 * The monitor will continue long enough to let the child
807 * run to its packet_disconnect(), but it must not allow any
808 * authentication to succeed.
809 */
810 debug_f("no valid authentication method lists");
811 }
812
813 debug3_f("sending MONITOR_ANS_PWNAM: %d", allowed);
814 mm_request_send(sock, MONITOR_ANS_PWNAM, m);
815
816 /* Allow service/style information on the auth context */
817 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1);
818 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1);
819
820 #ifdef USE_PAM
821 if (options.use_pam)
822 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1);
823 #endif
824
825 return (0);
826 }
827
mm_answer_auth2_read_banner(struct ssh * ssh,int sock,struct sshbuf * m)828 int mm_answer_auth2_read_banner(struct ssh *ssh, int sock, struct sshbuf *m)
829 {
830 char *banner;
831 int r;
832
833 sshbuf_reset(m);
834 banner = auth2_read_banner();
835 if ((r = sshbuf_put_cstring(m, banner != NULL ? banner : "")) != 0)
836 fatal_fr(r, "assemble");
837 mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m);
838 free(banner);
839
840 return (0);
841 }
842
843 int
mm_answer_authserv(struct ssh * ssh,int sock,struct sshbuf * m)844 mm_answer_authserv(struct ssh *ssh, int sock, struct sshbuf *m)
845 {
846 int r;
847
848 monitor_permit_authentications(1);
849
850 if ((r = sshbuf_get_cstring(m, &authctxt->service, NULL)) != 0 ||
851 (r = sshbuf_get_cstring(m, &authctxt->style, NULL)) != 0)
852 fatal_fr(r, "parse");
853 debug3_f("service=%s, style=%s", authctxt->service, authctxt->style);
854
855 if (strlen(authctxt->style) == 0) {
856 free(authctxt->style);
857 authctxt->style = NULL;
858 }
859
860 return (0);
861 }
862
863 /*
864 * Check that the key type appears in the supplied pattern list, ignoring
865 * mismatches in the signature algorithm. (Signature algorithm checks are
866 * performed in the unprivileged authentication code).
867 * Returns 1 on success, 0 otherwise.
868 */
869 static int
key_base_type_match(const char * method,const struct sshkey * key,const char * list)870 key_base_type_match(const char *method, const struct sshkey *key,
871 const char *list)
872 {
873 char *s, *l, *ol = xstrdup(list);
874 int found = 0;
875
876 l = ol;
877 for ((s = strsep(&l, ",")); s && *s != '\0'; (s = strsep(&l, ","))) {
878 if (sshkey_type_from_name(s) == key->type) {
879 found = 1;
880 break;
881 }
882 }
883 if (!found) {
884 error("%s key type %s is not in permitted list %s", method,
885 sshkey_ssh_name(key), list);
886 }
887
888 free(ol);
889 return found;
890 }
891
892 int
mm_answer_authpassword(struct ssh * ssh,int sock,struct sshbuf * m)893 mm_answer_authpassword(struct ssh *ssh, int sock, struct sshbuf *m)
894 {
895 static int call_count;
896 char *passwd;
897 int r, authenticated;
898 size_t plen;
899
900 if (!options.password_authentication)
901 fatal_f("password authentication not enabled");
902 if ((r = sshbuf_get_cstring(m, &passwd, &plen)) != 0)
903 fatal_fr(r, "parse");
904 /* Only authenticate if the context is valid */
905 authenticated = options.password_authentication &&
906 auth_password(ssh, passwd);
907 freezero(passwd, plen);
908
909 sshbuf_reset(m);
910 if ((r = sshbuf_put_u32(m, authenticated)) != 0)
911 fatal_fr(r, "assemble");
912 #ifdef USE_PAM
913 if ((r = sshbuf_put_u32(m, sshpam_get_maxtries_reached())) != 0)
914 fatal_fr(r, "assemble PAM");
915 #endif
916
917 debug3("%s: sending result %d", __func__, authenticated);
918 debug3_f("sending result %d", authenticated);
919 mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m);
920
921 call_count++;
922 if (plen == 0 && call_count == 1)
923 auth_method = "none";
924 else
925 auth_method = "password";
926
927 /* Causes monitor loop to terminate if authenticated */
928 return (authenticated);
929 }
930
931 #ifdef BSD_AUTH
932 int
mm_answer_bsdauthquery(struct ssh * ssh,int sock,struct sshbuf * m)933 mm_answer_bsdauthquery(struct ssh *ssh, int sock, struct sshbuf *m)
934 {
935 char *name, *infotxt;
936 u_int numprompts, *echo_on, success;
937 char **prompts;
938 int r;
939
940 if (!options.kbd_interactive_authentication)
941 fatal_f("kbd-int authentication not enabled");
942 success = bsdauth_query(authctxt, &name, &infotxt, &numprompts,
943 &prompts, &echo_on) < 0 ? 0 : 1;
944
945 sshbuf_reset(m);
946 if ((r = sshbuf_put_u32(m, success)) != 0)
947 fatal_fr(r, "assemble");
948 if (success) {
949 if ((r = sshbuf_put_cstring(m, prompts[0])) != 0)
950 fatal_fr(r, "assemble prompt");
951 }
952
953 debug3_f("sending challenge success: %u", success);
954 mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m);
955
956 if (success) {
957 free(name);
958 free(infotxt);
959 free(prompts);
960 free(echo_on);
961 }
962
963 return (0);
964 }
965
966 int
mm_answer_bsdauthrespond(struct ssh * ssh,int sock,struct sshbuf * m)967 mm_answer_bsdauthrespond(struct ssh *ssh, int sock, struct sshbuf *m)
968 {
969 char *response;
970 int r, authok;
971
972 if (!options.kbd_interactive_authentication)
973 fatal_f("kbd-int authentication not enabled");
974 if (authctxt->as == NULL)
975 fatal_f("no bsd auth session");
976
977 if ((r = sshbuf_get_cstring(m, &response, NULL)) != 0)
978 fatal_fr(r, "parse");
979 authok = options.kbd_interactive_authentication &&
980 auth_userresponse(authctxt->as, response, 0);
981 authctxt->as = NULL;
982 debug3_f("<%s> = <%d>", response, authok);
983 free(response);
984
985 sshbuf_reset(m);
986 if ((r = sshbuf_put_u32(m, authok)) != 0)
987 fatal_fr(r, "assemble");
988
989 debug3_f("sending authenticated: %d", authok);
990 mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m);
991
992 auth_method = "keyboard-interactive";
993 auth_submethod = "bsdauth";
994
995 return (authok != 0);
996 }
997 #endif
998
999 #ifdef USE_PAM
1000 int
mm_answer_pam_start(struct ssh * ssh,int sock,struct sshbuf * m)1001 mm_answer_pam_start(struct ssh *ssh, int sock, struct sshbuf *m)
1002 {
1003 if (!options.use_pam)
1004 fatal("UsePAM not set, but ended up in %s anyway", __func__);
1005
1006 start_pam(ssh);
1007
1008 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1);
1009 if (options.kbd_interactive_authentication)
1010 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_INIT_CTX, 1);
1011
1012 return (0);
1013 }
1014
1015 int
mm_answer_pam_account(struct ssh * ssh,int sock,struct sshbuf * m)1016 mm_answer_pam_account(struct ssh *ssh, int sock, struct sshbuf *m)
1017 {
1018 u_int ret;
1019 int r;
1020
1021 if (!options.use_pam)
1022 fatal("%s: PAM not enabled", __func__);
1023
1024 ret = do_pam_account();
1025
1026 if ((r = sshbuf_put_u32(m, ret)) != 0 ||
1027 (r = sshbuf_put_stringb(m, loginmsg)) != 0)
1028 fatal("%s: buffer error: %s", __func__, ssh_err(r));
1029
1030 mm_request_send(sock, MONITOR_ANS_PAM_ACCOUNT, m);
1031
1032 return (ret);
1033 }
1034
1035 static void *sshpam_ctxt, *sshpam_authok;
1036 extern KbdintDevice sshpam_device;
1037
1038 int
mm_answer_pam_init_ctx(struct ssh * ssh,int sock,struct sshbuf * m)1039 mm_answer_pam_init_ctx(struct ssh *ssh, int sock, struct sshbuf *m)
1040 {
1041 u_int ok = 0;
1042 int r;
1043
1044 debug3("%s", __func__);
1045 if (!options.kbd_interactive_authentication)
1046 fatal("%s: kbd-int authentication not enabled", __func__);
1047 if (sshpam_ctxt != NULL)
1048 fatal("%s: already called", __func__);
1049 sshpam_ctxt = (sshpam_device.init_ctx)(authctxt);
1050 sshpam_authok = NULL;
1051 sshbuf_reset(m);
1052 if (sshpam_ctxt != NULL) {
1053 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1);
1054 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_QUERY, 1);
1055 ok = 1;
1056 }
1057 if ((r = sshbuf_put_u32(m, ok)) != 0)
1058 fatal("%s: buffer error: %s", __func__, ssh_err(r));
1059 mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m);
1060 return (0);
1061 }
1062
1063 int
mm_answer_pam_query(struct ssh * ssh,int sock,struct sshbuf * m)1064 mm_answer_pam_query(struct ssh *ssh, int sock, struct sshbuf *m)
1065 {
1066 char *name = NULL, *info = NULL, **prompts = NULL;
1067 u_int i, num = 0, *echo_on = 0;
1068 int r, ret;
1069
1070 debug3("%s", __func__);
1071 sshpam_authok = NULL;
1072 if (sshpam_ctxt == NULL)
1073 fatal("%s: no context", __func__);
1074 ret = (sshpam_device.query)(sshpam_ctxt, &name, &info,
1075 &num, &prompts, &echo_on);
1076 if (ret == 0 && num == 0)
1077 sshpam_authok = sshpam_ctxt;
1078 if (num > 1 || name == NULL || info == NULL)
1079 fatal("sshpam_device.query failed");
1080 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_RESPOND, 1);
1081 sshbuf_reset(m);
1082 if ((r = sshbuf_put_u32(m, ret)) != 0 ||
1083 (r = sshbuf_put_cstring(m, name)) != 0 ||
1084 (r = sshbuf_put_cstring(m, info)) != 0 ||
1085 (r = sshbuf_put_u32(m, sshpam_get_maxtries_reached())) != 0 ||
1086 (r = sshbuf_put_u32(m, num)) != 0)
1087 fatal("%s: buffer error: %s", __func__, ssh_err(r));
1088 free(name);
1089 free(info);
1090 for (i = 0; i < num; ++i) {
1091 if ((r = sshbuf_put_cstring(m, prompts[i])) != 0 ||
1092 (r = sshbuf_put_u32(m, echo_on[i])) != 0)
1093 fatal("%s: buffer error: %s", __func__, ssh_err(r));
1094 free(prompts[i]);
1095 }
1096 free(prompts);
1097 free(echo_on);
1098 auth_method = "keyboard-interactive";
1099 auth_submethod = "pam";
1100 mm_request_send(sock, MONITOR_ANS_PAM_QUERY, m);
1101 return (0);
1102 }
1103
1104 int
mm_answer_pam_respond(struct ssh * ssh,int sock,struct sshbuf * m)1105 mm_answer_pam_respond(struct ssh *ssh, int sock, struct sshbuf *m)
1106 {
1107 char **resp;
1108 u_int i, num;
1109 int r, ret;
1110
1111 debug3("%s", __func__);
1112 if (sshpam_ctxt == NULL)
1113 fatal("%s: no context", __func__);
1114 sshpam_authok = NULL;
1115 if ((r = sshbuf_get_u32(m, &num)) != 0)
1116 fatal("%s: buffer error: %s", __func__, ssh_err(r));
1117 if (num > PAM_MAX_NUM_MSG) {
1118 fatal_f("Too many PAM messages, got %u, expected <= %u",
1119 num, (unsigned)PAM_MAX_NUM_MSG);
1120 }
1121 if (num > 0) {
1122 resp = xcalloc(num, sizeof(char *));
1123 for (i = 0; i < num; ++i) {
1124 if ((r = sshbuf_get_cstring(m, &(resp[i]), NULL)) != 0)
1125 fatal("%s: buffer error: %s",
1126 __func__, ssh_err(r));
1127 }
1128 ret = (sshpam_device.respond)(sshpam_ctxt, num, resp);
1129 for (i = 0; i < num; ++i)
1130 free(resp[i]);
1131 free(resp);
1132 } else {
1133 ret = (sshpam_device.respond)(sshpam_ctxt, num, NULL);
1134 }
1135 sshbuf_reset(m);
1136 if ((r = sshbuf_put_u32(m, ret)) != 0)
1137 fatal("%s: buffer error: %s", __func__, ssh_err(r));
1138 mm_request_send(sock, MONITOR_ANS_PAM_RESPOND, m);
1139 auth_method = "keyboard-interactive";
1140 auth_submethod = "pam";
1141 if (ret == 0)
1142 sshpam_authok = sshpam_ctxt;
1143 return (0);
1144 }
1145
1146 int
mm_answer_pam_free_ctx(struct ssh * ssh,int sock,struct sshbuf * m)1147 mm_answer_pam_free_ctx(struct ssh *ssh, int sock, struct sshbuf *m)
1148 {
1149 int r = sshpam_authok != NULL && sshpam_authok == sshpam_ctxt;
1150
1151 debug3("%s", __func__);
1152 if (sshpam_ctxt == NULL)
1153 fatal("%s: no context", __func__);
1154 (sshpam_device.free_ctx)(sshpam_ctxt);
1155 sshpam_ctxt = sshpam_authok = NULL;
1156 sshbuf_reset(m);
1157 mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m);
1158 /* Allow another attempt */
1159 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_INIT_CTX, 1);
1160 auth_method = "keyboard-interactive";
1161 auth_submethod = "pam";
1162 return r;
1163 }
1164 #endif
1165
1166 int
mm_answer_keyallowed(struct ssh * ssh,int sock,struct sshbuf * m)1167 mm_answer_keyallowed(struct ssh *ssh, int sock, struct sshbuf *m)
1168 {
1169 struct sshkey *key = NULL;
1170 char *cuser, *chost;
1171 u_int pubkey_auth_attempt;
1172 u_int type = 0;
1173 int r, allowed = 0;
1174 struct sshauthopt *opts = NULL;
1175
1176 debug3_f("entering");
1177 if ((r = sshbuf_get_u32(m, &type)) != 0 ||
1178 (r = sshbuf_get_cstring(m, &cuser, NULL)) != 0 ||
1179 (r = sshbuf_get_cstring(m, &chost, NULL)) != 0 ||
1180 (r = sshkey_froms(m, &key)) != 0 ||
1181 (r = sshbuf_get_u32(m, &pubkey_auth_attempt)) != 0)
1182 fatal_fr(r, "parse");
1183
1184 if (key != NULL && authctxt->valid) {
1185 switch (type) {
1186 case MM_USERKEY:
1187 auth_method = "publickey";
1188 if (!options.pubkey_authentication)
1189 break;
1190 if (auth2_key_already_used(authctxt, key))
1191 break;
1192 if (!key_base_type_match(auth_method, key,
1193 options.pubkey_accepted_algos))
1194 break;
1195 allowed = user_key_allowed(ssh, authctxt->pw, key,
1196 pubkey_auth_attempt, &opts);
1197 break;
1198 case MM_HOSTKEY:
1199 auth_method = "hostbased";
1200 if (!options.hostbased_authentication)
1201 break;
1202 if (auth2_key_already_used(authctxt, key))
1203 break;
1204 if (!key_base_type_match(auth_method, key,
1205 options.hostbased_accepted_algos))
1206 break;
1207 allowed = hostbased_key_allowed(ssh, authctxt->pw,
1208 cuser, chost, key);
1209 auth2_record_info(authctxt,
1210 "client user \"%.100s\", client host \"%.100s\"",
1211 cuser, chost);
1212 break;
1213 default:
1214 fatal_f("unknown key type %u", type);
1215 break;
1216 }
1217 }
1218
1219 debug3_f("%s authentication%s: %s key is %s", auth_method,
1220 pubkey_auth_attempt ? "" : " test",
1221 (key == NULL || !authctxt->valid) ? "invalid" : sshkey_type(key),
1222 allowed ? "allowed" : "not allowed");
1223
1224 auth2_record_key(authctxt, 0, key);
1225
1226 /* clear temporarily storage (used by verify) */
1227 monitor_reset_key_state();
1228
1229 if (allowed) {
1230 /* Save temporarily for comparison in verify */
1231 if ((r = sshkey_to_blob(key, &key_blob, &key_bloblen)) != 0)
1232 fatal_fr(r, "sshkey_to_blob");
1233 key_blobtype = type;
1234 key_opts = opts;
1235 hostbased_cuser = cuser;
1236 hostbased_chost = chost;
1237 } else {
1238 /* Log failed attempt */
1239 auth_log(ssh, 0, 0, auth_method, NULL);
1240 free(cuser);
1241 free(chost);
1242 }
1243 sshkey_free(key);
1244
1245 sshbuf_reset(m);
1246 if ((r = sshbuf_put_u32(m, allowed)) != 0)
1247 fatal_fr(r, "assemble");
1248 if (opts != NULL && (r = sshauthopt_serialise(opts, m, 1)) != 0)
1249 fatal_fr(r, "sshauthopt_serialise");
1250 mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m);
1251
1252 if (!allowed)
1253 sshauthopt_free(opts);
1254
1255 return (0);
1256 }
1257
1258 static int
monitor_valid_userblob(struct ssh * ssh,const u_char * data,u_int datalen)1259 monitor_valid_userblob(struct ssh *ssh, const u_char *data, u_int datalen)
1260 {
1261 struct sshbuf *b;
1262 struct sshkey *hostkey = NULL;
1263 const u_char *p;
1264 char *userstyle, *cp;
1265 size_t len;
1266 u_char type;
1267 int hostbound = 0, r, fail = 0;
1268
1269 if ((b = sshbuf_from(data, datalen)) == NULL)
1270 fatal_f("sshbuf_from");
1271
1272 if (ssh->compat & SSH_OLD_SESSIONID) {
1273 p = sshbuf_ptr(b);
1274 len = sshbuf_len(b);
1275 if ((session_id2 == NULL) ||
1276 (len < session_id2_len) ||
1277 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0))
1278 fail++;
1279 if ((r = sshbuf_consume(b, session_id2_len)) != 0)
1280 fatal_fr(r, "consume");
1281 } else {
1282 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0)
1283 fatal_fr(r, "parse sessionid");
1284 if ((session_id2 == NULL) ||
1285 (len != session_id2_len) ||
1286 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0))
1287 fail++;
1288 }
1289 if ((r = sshbuf_get_u8(b, &type)) != 0)
1290 fatal_fr(r, "parse type");
1291 if (type != SSH2_MSG_USERAUTH_REQUEST)
1292 fail++;
1293 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0)
1294 fatal_fr(r, "parse userstyle");
1295 xasprintf(&userstyle, "%s%s%s", authctxt->user,
1296 authctxt->style ? ":" : "",
1297 authctxt->style ? authctxt->style : "");
1298 if (strcmp(userstyle, cp) != 0) {
1299 logit("wrong user name passed to monitor: "
1300 "expected %s != %.100s", userstyle, cp);
1301 fail++;
1302 }
1303 free(userstyle);
1304 free(cp);
1305 if ((r = sshbuf_skip_string(b)) != 0 || /* service */
1306 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0)
1307 fatal_fr(r, "parse method");
1308 if (strcmp("publickey", cp) != 0) {
1309 if (strcmp("publickey-hostbound-v00@openssh.com", cp) == 0)
1310 hostbound = 1;
1311 else
1312 fail++;
1313 }
1314 free(cp);
1315 if ((r = sshbuf_get_u8(b, &type)) != 0)
1316 fatal_fr(r, "parse pktype");
1317 if (type == 0)
1318 fail++;
1319 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */
1320 (r = sshbuf_skip_string(b)) != 0 || /* pkblob */
1321 (hostbound && (r = sshkey_froms(b, &hostkey)) != 0))
1322 fatal_fr(r, "parse pk");
1323 if (sshbuf_len(b) != 0)
1324 fail++;
1325 sshbuf_free(b);
1326 if (hostkey != NULL) {
1327 /*
1328 * Ensure this is actually one of our hostkeys; unfortunately
1329 * can't check ssh->kex->initial_hostkey directly at this point
1330 * as packet state has not yet been exported to monitor.
1331 */
1332 if (get_hostkey_index(hostkey, 1, ssh) == -1)
1333 fatal_f("hostbound hostkey does not match");
1334 sshkey_free(hostkey);
1335 }
1336 return (fail == 0);
1337 }
1338
1339 static int
monitor_valid_hostbasedblob(const u_char * data,u_int datalen,const char * cuser,const char * chost)1340 monitor_valid_hostbasedblob(const u_char *data, u_int datalen,
1341 const char *cuser, const char *chost)
1342 {
1343 struct sshbuf *b;
1344 const u_char *p;
1345 char *cp, *userstyle;
1346 size_t len;
1347 int r, fail = 0;
1348 u_char type;
1349
1350 if ((b = sshbuf_from(data, datalen)) == NULL)
1351 fatal_f("sshbuf_new");
1352 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0)
1353 fatal_fr(r, "parse sessionid");
1354
1355 if ((session_id2 == NULL) ||
1356 (len != session_id2_len) ||
1357 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0))
1358 fail++;
1359
1360 if ((r = sshbuf_get_u8(b, &type)) != 0)
1361 fatal_fr(r, "parse type");
1362 if (type != SSH2_MSG_USERAUTH_REQUEST)
1363 fail++;
1364 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0)
1365 fatal_fr(r, "parse userstyle");
1366 xasprintf(&userstyle, "%s%s%s", authctxt->user,
1367 authctxt->style ? ":" : "",
1368 authctxt->style ? authctxt->style : "");
1369 if (strcmp(userstyle, cp) != 0) {
1370 logit("wrong user name passed to monitor: "
1371 "expected %s != %.100s", userstyle, cp);
1372 fail++;
1373 }
1374 free(userstyle);
1375 free(cp);
1376 if ((r = sshbuf_skip_string(b)) != 0 || /* service */
1377 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0)
1378 fatal_fr(r, "parse method");
1379 if (strcmp(cp, "hostbased") != 0)
1380 fail++;
1381 free(cp);
1382 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */
1383 (r = sshbuf_skip_string(b)) != 0) /* pkblob */
1384 fatal_fr(r, "parse pk");
1385
1386 /* verify client host, strip trailing dot if necessary */
1387 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0)
1388 fatal_fr(r, "parse host");
1389 if (((len = strlen(cp)) > 0) && cp[len - 1] == '.')
1390 cp[len - 1] = '\0';
1391 if (strcmp(cp, chost) != 0)
1392 fail++;
1393 free(cp);
1394
1395 /* verify client user */
1396 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0)
1397 fatal_fr(r, "parse ruser");
1398 if (strcmp(cp, cuser) != 0)
1399 fail++;
1400 free(cp);
1401
1402 if (sshbuf_len(b) != 0)
1403 fail++;
1404 sshbuf_free(b);
1405 return (fail == 0);
1406 }
1407
1408 int
mm_answer_keyverify(struct ssh * ssh,int sock,struct sshbuf * m)1409 mm_answer_keyverify(struct ssh *ssh, int sock, struct sshbuf *m)
1410 {
1411 struct sshkey *key;
1412 const u_char *signature, *data, *blob;
1413 char *sigalg = NULL, *fp = NULL;
1414 size_t signaturelen, datalen, bloblen;
1415 int r, ret, req_presence = 0, req_verify = 0, valid_data = 0;
1416 int encoded_ret;
1417 struct sshkey_sig_details *sig_details = NULL;
1418
1419 if ((r = sshbuf_get_string_direct(m, &blob, &bloblen)) != 0 ||
1420 (r = sshbuf_get_string_direct(m, &signature, &signaturelen)) != 0 ||
1421 (r = sshbuf_get_string_direct(m, &data, &datalen)) != 0 ||
1422 (r = sshbuf_get_cstring(m, &sigalg, NULL)) != 0)
1423 fatal_fr(r, "parse");
1424
1425 if (hostbased_cuser == NULL || hostbased_chost == NULL ||
1426 !monitor_allowed_key(blob, bloblen))
1427 fatal_f("bad key, not previously allowed");
1428
1429 /* Empty signature algorithm means NULL. */
1430 if (*sigalg == '\0') {
1431 free(sigalg);
1432 sigalg = NULL;
1433 }
1434
1435 /* XXX use sshkey_froms here; need to change key_blob, etc. */
1436 if ((r = sshkey_from_blob(blob, bloblen, &key)) != 0)
1437 fatal_fr(r, "parse key");
1438
1439 switch (key_blobtype) {
1440 case MM_USERKEY:
1441 valid_data = monitor_valid_userblob(ssh, data, datalen);
1442 auth_method = "publickey";
1443 break;
1444 case MM_HOSTKEY:
1445 valid_data = monitor_valid_hostbasedblob(data, datalen,
1446 hostbased_cuser, hostbased_chost);
1447 auth_method = "hostbased";
1448 break;
1449 default:
1450 valid_data = 0;
1451 break;
1452 }
1453 if (!valid_data)
1454 fatal_f("bad %s signature data blob",
1455 key_blobtype == MM_USERKEY ? "userkey" :
1456 (key_blobtype == MM_HOSTKEY ? "hostkey" : "unknown"));
1457
1458 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash,
1459 SSH_FP_DEFAULT)) == NULL)
1460 fatal_f("sshkey_fingerprint failed");
1461
1462 ret = sshkey_verify(key, signature, signaturelen, data, datalen,
1463 sigalg, ssh->compat, &sig_details);
1464 debug3_f("%s %s signature using %s %s%s%s", auth_method,
1465 sshkey_type(key), sigalg == NULL ? "default" : sigalg,
1466 (ret == 0) ? "verified" : "unverified",
1467 (ret != 0) ? ": " : "", (ret != 0) ? ssh_err(ret) : "");
1468
1469 if (ret == 0 && key_blobtype == MM_USERKEY && sig_details != NULL) {
1470 req_presence = (options.pubkey_auth_options &
1471 PUBKEYAUTH_TOUCH_REQUIRED) ||
1472 !key_opts->no_require_user_presence;
1473 if (req_presence &&
1474 (sig_details->sk_flags & SSH_SK_USER_PRESENCE_REQD) == 0) {
1475 error("public key %s %s signature for %s%s from %.128s "
1476 "port %d rejected: user presence "
1477 "(authenticator touch) requirement not met ",
1478 sshkey_type(key), fp,
1479 authctxt->valid ? "" : "invalid user ",
1480 authctxt->user, ssh_remote_ipaddr(ssh),
1481 ssh_remote_port(ssh));
1482 ret = SSH_ERR_SIGNATURE_INVALID;
1483 }
1484 req_verify = (options.pubkey_auth_options &
1485 PUBKEYAUTH_VERIFY_REQUIRED) || key_opts->require_verify;
1486 if (req_verify &&
1487 (sig_details->sk_flags & SSH_SK_USER_VERIFICATION_REQD) == 0) {
1488 error("public key %s %s signature for %s%s from %.128s "
1489 "port %d rejected: user verification requirement "
1490 "not met ", sshkey_type(key), fp,
1491 authctxt->valid ? "" : "invalid user ",
1492 authctxt->user, ssh_remote_ipaddr(ssh),
1493 ssh_remote_port(ssh));
1494 ret = SSH_ERR_SIGNATURE_INVALID;
1495 }
1496 }
1497 auth2_record_key(authctxt, ret == 0, key);
1498
1499 if (key_blobtype == MM_USERKEY)
1500 auth_activate_options(ssh, key_opts);
1501 monitor_reset_key_state();
1502
1503 sshbuf_reset(m);
1504
1505 /* encode ret != 0 as positive integer, since we're sending u32 */
1506 encoded_ret = (ret != 0);
1507 if ((r = sshbuf_put_u32(m, encoded_ret)) != 0 ||
1508 (r = sshbuf_put_u8(m, sig_details != NULL)) != 0)
1509 fatal_fr(r, "assemble");
1510 if (sig_details != NULL) {
1511 if ((r = sshbuf_put_u32(m, sig_details->sk_counter)) != 0 ||
1512 (r = sshbuf_put_u8(m, sig_details->sk_flags)) != 0)
1513 fatal_fr(r, "assemble sk");
1514 }
1515 sshkey_sig_details_free(sig_details);
1516 mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m);
1517
1518 free(sigalg);
1519 free(fp);
1520 sshkey_free(key);
1521
1522 return ret == 0;
1523 }
1524
1525 static void
mm_record_login(struct ssh * ssh,Session * s,struct passwd * pw)1526 mm_record_login(struct ssh *ssh, Session *s, struct passwd *pw)
1527 {
1528 socklen_t fromlen;
1529 struct sockaddr_storage from;
1530
1531 /*
1532 * Get IP address of client. If the connection is not a socket, let
1533 * the address be 0.0.0.0.
1534 */
1535 memset(&from, 0, sizeof(from));
1536 fromlen = sizeof(from);
1537 if (ssh_packet_connection_is_on_socket(ssh)) {
1538 if (getpeername(ssh_packet_get_connection_in(ssh),
1539 (struct sockaddr *)&from, &fromlen) == -1) {
1540 debug("getpeername: %.100s", strerror(errno));
1541 cleanup_exit(255);
1542 }
1543 }
1544 /* Record that there was a login on that tty from the remote host. */
1545 record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid,
1546 session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns),
1547 (struct sockaddr *)&from, fromlen);
1548 }
1549
1550 static void
mm_session_close(Session * s)1551 mm_session_close(Session *s)
1552 {
1553 debug3_f("session %d pid %ld", s->self, (long)s->pid);
1554 if (s->ttyfd != -1) {
1555 debug3_f("tty %s ptyfd %d", s->tty, s->ptyfd);
1556 session_pty_cleanup2(s);
1557 }
1558 session_unused(s->self);
1559 }
1560
1561 int
mm_answer_pty(struct ssh * ssh,int sock,struct sshbuf * m)1562 mm_answer_pty(struct ssh *ssh, int sock, struct sshbuf *m)
1563 {
1564 extern struct monitor *pmonitor;
1565 Session *s;
1566 int r, res, fd0;
1567
1568 debug3_f("entering");
1569
1570 sshbuf_reset(m);
1571 s = session_new();
1572 if (s == NULL)
1573 goto error;
1574 s->authctxt = authctxt;
1575 s->pw = authctxt->pw;
1576 s->pid = pmonitor->m_pid;
1577 res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty));
1578 if (res == 0)
1579 goto error;
1580 pty_setowner(authctxt->pw, s->tty);
1581
1582 if ((r = sshbuf_put_u32(m, 1)) != 0 ||
1583 (r = sshbuf_put_cstring(m, s->tty)) != 0)
1584 fatal_fr(r, "assemble");
1585
1586 /* We need to trick ttyslot */
1587 if (dup2(s->ttyfd, 0) == -1)
1588 fatal_f("dup2");
1589
1590 mm_record_login(ssh, s, authctxt->pw);
1591
1592 /* Now we can close the file descriptor again */
1593 close(0);
1594
1595 /* send messages generated by record_login */
1596 if ((r = sshbuf_put_stringb(m, loginmsg)) != 0)
1597 fatal_fr(r, "assemble loginmsg");
1598 sshbuf_reset(loginmsg);
1599
1600 mm_request_send(sock, MONITOR_ANS_PTY, m);
1601
1602 if (mm_send_fd(sock, s->ptyfd) == -1 ||
1603 mm_send_fd(sock, s->ttyfd) == -1)
1604 fatal_f("send fds failed");
1605
1606 /* make sure nothing uses fd 0 */
1607 if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) == -1)
1608 fatal_f("open(/dev/null): %s", strerror(errno));
1609 if (fd0 != 0)
1610 error_f("fd0 %d != 0", fd0);
1611
1612 /* slave side of pty is not needed */
1613 close(s->ttyfd);
1614 s->ttyfd = s->ptyfd;
1615 /* no need to dup() because nobody closes ptyfd */
1616 s->ptymaster = s->ptyfd;
1617
1618 debug3_f("tty %s ptyfd %d", s->tty, s->ttyfd);
1619
1620 return (0);
1621
1622 error:
1623 if (s != NULL)
1624 mm_session_close(s);
1625 if ((r = sshbuf_put_u32(m, 0)) != 0)
1626 fatal_fr(r, "assemble 0");
1627 mm_request_send(sock, MONITOR_ANS_PTY, m);
1628 return (0);
1629 }
1630
1631 int
mm_answer_pty_cleanup(struct ssh * ssh,int sock,struct sshbuf * m)1632 mm_answer_pty_cleanup(struct ssh *ssh, int sock, struct sshbuf *m)
1633 {
1634 Session *s;
1635 char *tty;
1636 int r;
1637
1638 debug3_f("entering");
1639
1640 if ((r = sshbuf_get_cstring(m, &tty, NULL)) != 0)
1641 fatal_fr(r, "parse tty");
1642 if ((s = session_by_tty(tty)) != NULL)
1643 mm_session_close(s);
1644 sshbuf_reset(m);
1645 free(tty);
1646 return (0);
1647 }
1648
1649 int
mm_answer_term(struct ssh * ssh,int sock,struct sshbuf * req)1650 mm_answer_term(struct ssh *ssh, int sock, struct sshbuf *req)
1651 {
1652 extern struct monitor *pmonitor;
1653 int res, status;
1654
1655 debug3_f("tearing down sessions");
1656
1657 /* The child is terminating */
1658 session_destroy_all(ssh, &mm_session_close);
1659
1660 #ifdef USE_PAM
1661 if (options.use_pam)
1662 sshpam_cleanup();
1663 #endif
1664
1665 while (waitpid(pmonitor->m_pid, &status, 0) == -1)
1666 if (errno != EINTR)
1667 exit(1);
1668
1669 res = WIFEXITED(status) ? WEXITSTATUS(status) : 1;
1670
1671 /* Terminate process */
1672 exit(res);
1673 }
1674
1675 #ifdef SSH_AUDIT_EVENTS
1676 /* Report that an audit event occurred */
1677 int
mm_answer_audit_event(struct ssh * ssh,int socket,struct sshbuf * m)1678 mm_answer_audit_event(struct ssh *ssh, int socket, struct sshbuf *m)
1679 {
1680 u_int n;
1681 ssh_audit_event_t event;
1682 int r;
1683
1684 debug3("%s entering", __func__);
1685
1686 if ((r = sshbuf_get_u32(m, &n)) != 0)
1687 fatal("%s: buffer error: %s", __func__, ssh_err(r));
1688 event = (ssh_audit_event_t)n;
1689 switch (event) {
1690 case SSH_AUTH_FAIL_PUBKEY:
1691 case SSH_AUTH_FAIL_HOSTBASED:
1692 case SSH_AUTH_FAIL_GSSAPI:
1693 case SSH_LOGIN_EXCEED_MAXTRIES:
1694 case SSH_LOGIN_ROOT_DENIED:
1695 case SSH_CONNECTION_CLOSE:
1696 case SSH_INVALID_USER:
1697 audit_event(ssh, event);
1698 break;
1699 default:
1700 fatal("Audit event type %d not permitted", event);
1701 }
1702
1703 return (0);
1704 }
1705
1706 int
mm_answer_audit_command(struct ssh * ssh,int socket,struct sshbuf * m)1707 mm_answer_audit_command(struct ssh *ssh, int socket, struct sshbuf *m)
1708 {
1709 char *cmd;
1710 int r;
1711
1712 debug3("%s entering", __func__);
1713 if ((r = sshbuf_get_cstring(m, &cmd, NULL)) != 0)
1714 fatal("%s: buffer error: %s", __func__, ssh_err(r));
1715 /* sanity check command, if so how? */
1716 audit_run_command(cmd);
1717 free(cmd);
1718 return (0);
1719 }
1720 #endif /* SSH_AUDIT_EVENTS */
1721
1722 void
monitor_clear_keystate(struct ssh * ssh,struct monitor * pmonitor)1723 monitor_clear_keystate(struct ssh *ssh, struct monitor *pmonitor)
1724 {
1725 ssh_clear_newkeys(ssh, MODE_IN);
1726 ssh_clear_newkeys(ssh, MODE_OUT);
1727 sshbuf_free(child_state);
1728 child_state = NULL;
1729 }
1730
1731 void
monitor_apply_keystate(struct ssh * ssh,struct monitor * pmonitor)1732 monitor_apply_keystate(struct ssh *ssh, struct monitor *pmonitor)
1733 {
1734 struct kex *kex;
1735 int r;
1736
1737 debug3_f("packet_set_state");
1738 if ((r = ssh_packet_set_state(ssh, child_state)) != 0)
1739 fatal_fr(r, "packet_set_state");
1740 sshbuf_free(child_state);
1741 child_state = NULL;
1742 if ((kex = ssh->kex) == NULL)
1743 fatal_f("internal error: ssh->kex == NULL");
1744 if (session_id2_len != sshbuf_len(ssh->kex->session_id)) {
1745 fatal_f("incorrect session id length %zu (expected %u)",
1746 sshbuf_len(ssh->kex->session_id), session_id2_len);
1747 }
1748 if (memcmp(sshbuf_ptr(ssh->kex->session_id), session_id2,
1749 session_id2_len) != 0)
1750 fatal_f("session ID mismatch");
1751 /* XXX set callbacks */
1752 #ifdef WITH_OPENSSL
1753 kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_server;
1754 kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_server;
1755 kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_server;
1756 kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_server;
1757 kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_server;
1758 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
1759 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
1760 # ifdef OPENSSL_HAS_ECC
1761 kex->kex[KEX_ECDH_SHA2] = kex_gen_server;
1762 # endif
1763 #endif /* WITH_OPENSSL */
1764 kex->kex[KEX_C25519_SHA256] = kex_gen_server;
1765 kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_server;
1766 kex->load_host_public_key=&get_hostkey_public_by_type;
1767 kex->load_host_private_key=&get_hostkey_private_by_type;
1768 kex->host_key_index=&get_hostkey_index;
1769 kex->sign = sshd_hostkey_sign;
1770 }
1771
1772 /* This function requires careful sanity checking */
1773
1774 void
mm_get_keystate(struct ssh * ssh,struct monitor * pmonitor)1775 mm_get_keystate(struct ssh *ssh, struct monitor *pmonitor)
1776 {
1777 debug3_f("Waiting for new keys");
1778
1779 if ((child_state = sshbuf_new()) == NULL)
1780 fatal_f("sshbuf_new failed");
1781 mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT,
1782 child_state);
1783 debug3_f("GOT new keys");
1784 }
1785
1786
1787 /* XXX */
1788
1789 #define FD_CLOSEONEXEC(x) do { \
1790 if (fcntl(x, F_SETFD, FD_CLOEXEC) == -1) \
1791 fatal("fcntl(%d, F_SETFD)", x); \
1792 } while (0)
1793
1794 static void
monitor_openfds(struct monitor * mon,int do_logfds)1795 monitor_openfds(struct monitor *mon, int do_logfds)
1796 {
1797 int pair[2];
1798 #ifdef SO_ZEROIZE
1799 int on = 1;
1800 #endif
1801
1802 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1)
1803 fatal_f("socketpair: %s", strerror(errno));
1804 #ifdef SO_ZEROIZE
1805 if (setsockopt(pair[0], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1)
1806 error("setsockopt SO_ZEROIZE(0): %.100s", strerror(errno));
1807 if (setsockopt(pair[1], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1)
1808 error("setsockopt SO_ZEROIZE(1): %.100s", strerror(errno));
1809 #endif
1810 FD_CLOSEONEXEC(pair[0]);
1811 FD_CLOSEONEXEC(pair[1]);
1812 mon->m_recvfd = pair[0];
1813 mon->m_sendfd = pair[1];
1814
1815 if (do_logfds) {
1816 if (pipe(pair) == -1)
1817 fatal_f("pipe: %s", strerror(errno));
1818 FD_CLOSEONEXEC(pair[0]);
1819 FD_CLOSEONEXEC(pair[1]);
1820 mon->m_log_recvfd = pair[0];
1821 mon->m_log_sendfd = pair[1];
1822 } else
1823 mon->m_log_recvfd = mon->m_log_sendfd = -1;
1824 }
1825
1826 #define MM_MEMSIZE 65536
1827
1828 struct monitor *
monitor_init(void)1829 monitor_init(void)
1830 {
1831 struct monitor *mon;
1832
1833 mon = xcalloc(1, sizeof(*mon));
1834 monitor_openfds(mon, 1);
1835
1836 return mon;
1837 }
1838
1839 void
monitor_reinit(struct monitor * mon)1840 monitor_reinit(struct monitor *mon)
1841 {
1842 monitor_openfds(mon, 0);
1843 }
1844
1845 #ifdef GSSAPI
1846 int
mm_answer_gss_setup_ctx(struct ssh * ssh,int sock,struct sshbuf * m)1847 mm_answer_gss_setup_ctx(struct ssh *ssh, int sock, struct sshbuf *m)
1848 {
1849 gss_OID_desc goid;
1850 OM_uint32 major;
1851 size_t len;
1852 u_char *p;
1853 int r;
1854
1855 if (!options.gss_authentication)
1856 fatal_f("GSSAPI authentication not enabled");
1857
1858 if ((r = sshbuf_get_string(m, &p, &len)) != 0)
1859 fatal_fr(r, "parse");
1860 goid.elements = p;
1861 goid.length = len;
1862
1863 major = ssh_gssapi_server_ctx(&gsscontext, &goid);
1864
1865 free(goid.elements);
1866
1867 sshbuf_reset(m);
1868 if ((r = sshbuf_put_u32(m, major)) != 0)
1869 fatal_fr(r, "assemble");
1870
1871 mm_request_send(sock, MONITOR_ANS_GSSSETUP, m);
1872
1873 /* Now we have a context, enable the step */
1874 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1);
1875
1876 return (0);
1877 }
1878
1879 int
mm_answer_gss_accept_ctx(struct ssh * ssh,int sock,struct sshbuf * m)1880 mm_answer_gss_accept_ctx(struct ssh *ssh, int sock, struct sshbuf *m)
1881 {
1882 gss_buffer_desc in;
1883 gss_buffer_desc out = GSS_C_EMPTY_BUFFER;
1884 OM_uint32 major, minor;
1885 OM_uint32 flags = 0; /* GSI needs this */
1886 int r;
1887
1888 if (!options.gss_authentication)
1889 fatal_f("GSSAPI authentication not enabled");
1890
1891 if ((r = ssh_gssapi_get_buffer_desc(m, &in)) != 0)
1892 fatal_fr(r, "ssh_gssapi_get_buffer_desc");
1893 major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags);
1894 free(in.value);
1895
1896 sshbuf_reset(m);
1897 if ((r = sshbuf_put_u32(m, major)) != 0 ||
1898 (r = sshbuf_put_string(m, out.value, out.length)) != 0 ||
1899 (r = sshbuf_put_u32(m, flags)) != 0)
1900 fatal_fr(r, "assemble");
1901 mm_request_send(sock, MONITOR_ANS_GSSSTEP, m);
1902
1903 gss_release_buffer(&minor, &out);
1904
1905 if (major == GSS_S_COMPLETE) {
1906 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0);
1907 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
1908 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1);
1909 }
1910 return (0);
1911 }
1912
1913 int
mm_answer_gss_checkmic(struct ssh * ssh,int sock,struct sshbuf * m)1914 mm_answer_gss_checkmic(struct ssh *ssh, int sock, struct sshbuf *m)
1915 {
1916 gss_buffer_desc gssbuf, mic;
1917 OM_uint32 ret;
1918 int r;
1919
1920 if (!options.gss_authentication)
1921 fatal_f("GSSAPI authentication not enabled");
1922
1923 if ((r = ssh_gssapi_get_buffer_desc(m, &gssbuf)) != 0 ||
1924 (r = ssh_gssapi_get_buffer_desc(m, &mic)) != 0)
1925 fatal_fr(r, "ssh_gssapi_get_buffer_desc");
1926
1927 ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic);
1928
1929 free(gssbuf.value);
1930 free(mic.value);
1931
1932 sshbuf_reset(m);
1933 if ((r = sshbuf_put_u32(m, ret)) != 0)
1934 fatal_fr(r, "assemble");
1935
1936 mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m);
1937
1938 if (!GSS_ERROR(ret))
1939 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
1940
1941 return (0);
1942 }
1943
1944 int
mm_answer_gss_userok(struct ssh * ssh,int sock,struct sshbuf * m)1945 mm_answer_gss_userok(struct ssh *ssh, int sock, struct sshbuf *m)
1946 {
1947 int r, authenticated;
1948 const char *displayname;
1949
1950 if (!options.gss_authentication)
1951 fatal_f("GSSAPI authentication not enabled");
1952
1953 authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user);
1954
1955 sshbuf_reset(m);
1956 if ((r = sshbuf_put_u32(m, authenticated)) != 0)
1957 fatal_fr(r, "assemble");
1958
1959 debug3_f("sending result %d", authenticated);
1960 mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m);
1961
1962 auth_method = "gssapi-with-mic";
1963
1964 if ((displayname = ssh_gssapi_displayname()) != NULL)
1965 auth2_record_info(authctxt, "%s", displayname);
1966
1967 /* Monitor loop will terminate if authenticated */
1968 return (authenticated);
1969 }
1970 #endif /* GSSAPI */
1971
1972