1 /* $OpenBSD: monitor.c,v 1.237 2023/08/16 16:14:11 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 int mm_answer_sesskey(struct ssh *, int, struct sshbuf *);
129 int mm_answer_sessid(struct ssh *, int, struct sshbuf *);
130
131 #ifdef USE_PAM
132 int mm_answer_pam_start(struct ssh *, int, struct sshbuf *);
133 int mm_answer_pam_account(struct ssh *, int, struct sshbuf *);
134 int mm_answer_pam_init_ctx(struct ssh *, int, struct sshbuf *);
135 int mm_answer_pam_query(struct ssh *, int, struct sshbuf *);
136 int mm_answer_pam_respond(struct ssh *, int, struct sshbuf *);
137 int mm_answer_pam_free_ctx(struct ssh *, int, struct sshbuf *);
138 #endif
139
140 #ifdef GSSAPI
141 int mm_answer_gss_setup_ctx(struct ssh *, int, struct sshbuf *);
142 int mm_answer_gss_accept_ctx(struct ssh *, int, struct sshbuf *);
143 int mm_answer_gss_userok(struct ssh *, int, struct sshbuf *);
144 int mm_answer_gss_checkmic(struct ssh *, int, struct sshbuf *);
145 #endif
146
147 #ifdef SSH_AUDIT_EVENTS
148 int mm_answer_audit_event(struct ssh *, int, struct sshbuf *);
149 int mm_answer_audit_command(struct ssh *, int, struct sshbuf *);
150 #endif
151
152 static Authctxt *authctxt;
153
154 /* local state for key verify */
155 static u_char *key_blob = NULL;
156 static size_t key_bloblen = 0;
157 static u_int key_blobtype = MM_NOKEY;
158 static struct sshauthopt *key_opts = NULL;
159 static char *hostbased_cuser = NULL;
160 static char *hostbased_chost = NULL;
161 static char *auth_method = "unknown";
162 static char *auth_submethod = NULL;
163 static u_int session_id2_len = 0;
164 static u_char *session_id2 = NULL;
165 static pid_t monitor_child_pid;
166
167 struct mon_table {
168 enum monitor_reqtype type;
169 int flags;
170 int (*f)(struct ssh *, int, struct sshbuf *);
171 };
172
173 #define MON_ISAUTH 0x0004 /* Required for Authentication */
174 #define MON_AUTHDECIDE 0x0008 /* Decides Authentication */
175 #define MON_ONCE 0x0010 /* Disable after calling */
176 #define MON_ALOG 0x0020 /* Log auth attempt without authenticating */
177
178 #define MON_AUTH (MON_ISAUTH|MON_AUTHDECIDE)
179
180 #define MON_PERMIT 0x1000 /* Request is permitted */
181
182 static int monitor_read(struct ssh *, struct monitor *, struct mon_table *,
183 struct mon_table **);
184 static int monitor_read_log(struct monitor *);
185
186 struct mon_table mon_dispatch_proto20[] = {
187 #ifdef WITH_OPENSSL
188 {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli},
189 #endif
190 {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign},
191 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow},
192 {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv},
193 {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner},
194 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword},
195 #ifdef USE_PAM
196 {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start},
197 {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account},
198 {MONITOR_REQ_PAM_INIT_CTX, MON_ONCE, mm_answer_pam_init_ctx},
199 {MONITOR_REQ_PAM_QUERY, 0, mm_answer_pam_query},
200 {MONITOR_REQ_PAM_RESPOND, MON_ONCE, mm_answer_pam_respond},
201 {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx},
202 #endif
203 #ifdef SSH_AUDIT_EVENTS
204 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
205 #endif
206 #ifdef BSD_AUTH
207 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery},
208 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond},
209 #endif
210 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed},
211 {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify},
212 #ifdef GSSAPI
213 {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx},
214 {MONITOR_REQ_GSSSTEP, 0, mm_answer_gss_accept_ctx},
215 {MONITOR_REQ_GSSUSEROK, MON_ONCE|MON_AUTHDECIDE, mm_answer_gss_userok},
216 {MONITOR_REQ_GSSCHECKMIC, MON_ONCE, mm_answer_gss_checkmic},
217 #endif
218 {0, 0, NULL}
219 };
220
221 struct mon_table mon_dispatch_postauth20[] = {
222 #ifdef WITH_OPENSSL
223 {MONITOR_REQ_MODULI, 0, mm_answer_moduli},
224 #endif
225 {MONITOR_REQ_SIGN, 0, mm_answer_sign},
226 {MONITOR_REQ_PTY, 0, mm_answer_pty},
227 {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup},
228 {MONITOR_REQ_TERM, 0, mm_answer_term},
229 #ifdef SSH_AUDIT_EVENTS
230 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
231 {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT, mm_answer_audit_command},
232 #endif
233 {0, 0, NULL}
234 };
235
236 struct mon_table *mon_dispatch;
237
238 /* Specifies if a certain message is allowed at the moment */
239 static void
monitor_permit(struct mon_table * ent,enum monitor_reqtype type,int permit)240 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit)
241 {
242 while (ent->f != NULL) {
243 if (ent->type == type) {
244 ent->flags &= ~MON_PERMIT;
245 ent->flags |= permit ? MON_PERMIT : 0;
246 return;
247 }
248 ent++;
249 }
250 }
251
252 static void
monitor_permit_authentications(int permit)253 monitor_permit_authentications(int permit)
254 {
255 struct mon_table *ent = mon_dispatch;
256
257 while (ent->f != NULL) {
258 if (ent->flags & MON_AUTH) {
259 ent->flags &= ~MON_PERMIT;
260 ent->flags |= permit ? MON_PERMIT : 0;
261 }
262 ent++;
263 }
264 }
265
266 void
monitor_child_preauth(struct ssh * ssh,struct monitor * pmonitor)267 monitor_child_preauth(struct ssh *ssh, struct monitor *pmonitor)
268 {
269 struct mon_table *ent;
270 int authenticated = 0, partial = 0;
271
272 debug3("preauth child monitor started");
273
274 if (pmonitor->m_recvfd >= 0)
275 close(pmonitor->m_recvfd);
276 if (pmonitor->m_log_sendfd >= 0)
277 close(pmonitor->m_log_sendfd);
278 pmonitor->m_log_sendfd = pmonitor->m_recvfd = -1;
279
280 authctxt = (Authctxt *)ssh->authctxt;
281 memset(authctxt, 0, sizeof(*authctxt));
282 ssh->authctxt = authctxt;
283
284 authctxt->loginmsg = loginmsg;
285
286 mon_dispatch = mon_dispatch_proto20;
287 /* Permit requests for moduli and signatures */
288 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
289 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
290
291 /* The first few requests do not require asynchronous access */
292 while (!authenticated) {
293 partial = 0;
294 auth_method = "unknown";
295 auth_submethod = NULL;
296 auth2_authctxt_reset_info(authctxt);
297
298 authenticated = (monitor_read(ssh, pmonitor,
299 mon_dispatch, &ent) == 1);
300
301 /* Special handling for multiple required authentications */
302 if (options.num_auth_methods != 0) {
303 if (authenticated &&
304 !auth2_update_methods_lists(authctxt,
305 auth_method, auth_submethod)) {
306 debug3_f("method %s: partial", auth_method);
307 authenticated = 0;
308 partial = 1;
309 }
310 }
311
312 if (authenticated) {
313 if (!(ent->flags & MON_AUTHDECIDE))
314 fatal_f("unexpected authentication from %d",
315 ent->type);
316 if (authctxt->pw->pw_uid == 0 &&
317 !auth_root_allowed(ssh, auth_method))
318 authenticated = 0;
319 #ifdef USE_PAM
320 /* PAM needs to perform account checks after auth */
321 if (options.use_pam && authenticated) {
322 struct sshbuf *m;
323
324 if ((m = sshbuf_new()) == NULL)
325 fatal("%s: sshbuf_new failed",
326 __func__);
327 mm_request_receive_expect(pmonitor->m_sendfd,
328 MONITOR_REQ_PAM_ACCOUNT, m);
329 authenticated = mm_answer_pam_account(
330 ssh, pmonitor->m_sendfd, m);
331 sshbuf_free(m);
332 }
333 #endif
334 }
335 if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) {
336 auth_log(ssh, authenticated, partial,
337 auth_method, auth_submethod);
338 if (!partial && !authenticated)
339 authctxt->failures++;
340 if (authenticated || partial) {
341 auth2_update_session_info(authctxt,
342 auth_method, auth_submethod);
343 }
344 }
345 if (authctxt->failures > options.max_authtries) {
346 /* Shouldn't happen */
347 fatal_f("privsep child made too many authentication "
348 "attempts");
349 }
350 }
351
352 if (!authctxt->valid)
353 fatal_f("authenticated invalid user");
354 if (strcmp(auth_method, "unknown") == 0)
355 fatal_f("authentication method name unknown");
356
357 debug_f("user %s authenticated by privileged process", authctxt->user);
358 ssh->authctxt = NULL;
359 ssh_packet_set_log_preamble(ssh, "user %s", authctxt->user);
360
361 mm_get_keystate(ssh, pmonitor);
362
363 /* Drain any buffered messages from the child */
364 while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0)
365 ;
366
367 if (pmonitor->m_recvfd >= 0)
368 close(pmonitor->m_recvfd);
369 if (pmonitor->m_log_sendfd >= 0)
370 close(pmonitor->m_log_sendfd);
371 pmonitor->m_sendfd = pmonitor->m_log_recvfd = -1;
372 }
373
374 static void
monitor_set_child_handler(pid_t pid)375 monitor_set_child_handler(pid_t pid)
376 {
377 monitor_child_pid = pid;
378 }
379
380 static void
monitor_child_handler(int sig)381 monitor_child_handler(int sig)
382 {
383 kill(monitor_child_pid, sig);
384 }
385
386 void
monitor_child_postauth(struct ssh * ssh,struct monitor * pmonitor)387 monitor_child_postauth(struct ssh *ssh, struct monitor *pmonitor)
388 {
389 close(pmonitor->m_recvfd);
390 pmonitor->m_recvfd = -1;
391
392 monitor_set_child_handler(pmonitor->m_pid);
393 ssh_signal(SIGHUP, &monitor_child_handler);
394 ssh_signal(SIGTERM, &monitor_child_handler);
395 ssh_signal(SIGINT, &monitor_child_handler);
396 #ifdef SIGXFSZ
397 ssh_signal(SIGXFSZ, SIG_IGN);
398 #endif
399
400 mon_dispatch = mon_dispatch_postauth20;
401
402 /* Permit requests for moduli and signatures */
403 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
404 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
405 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1);
406
407 if (auth_opts->permit_pty_flag) {
408 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1);
409 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1);
410 }
411
412 for (;;)
413 monitor_read(ssh, pmonitor, mon_dispatch, NULL);
414 }
415
416 static int
monitor_read_log(struct monitor * pmonitor)417 monitor_read_log(struct monitor *pmonitor)
418 {
419 struct sshbuf *logmsg;
420 u_int len, level, forced;
421 char *msg;
422 u_char *p;
423 int r;
424
425 if ((logmsg = sshbuf_new()) == NULL)
426 fatal_f("sshbuf_new");
427
428 /* Read length */
429 if ((r = sshbuf_reserve(logmsg, 4, &p)) != 0)
430 fatal_fr(r, "reserve len");
431 if (atomicio(read, pmonitor->m_log_recvfd, p, 4) != 4) {
432 if (errno == EPIPE) {
433 sshbuf_free(logmsg);
434 debug_f("child log fd closed");
435 close(pmonitor->m_log_recvfd);
436 pmonitor->m_log_recvfd = -1;
437 return -1;
438 }
439 fatal_f("log fd read: %s", strerror(errno));
440 }
441 if ((r = sshbuf_get_u32(logmsg, &len)) != 0)
442 fatal_fr(r, "parse len");
443 if (len <= 4 || len > 8192)
444 fatal_f("invalid log message length %u", len);
445
446 /* Read severity, message */
447 sshbuf_reset(logmsg);
448 if ((r = sshbuf_reserve(logmsg, len, &p)) != 0)
449 fatal_fr(r, "reserve msg");
450 if (atomicio(read, pmonitor->m_log_recvfd, p, len) != len)
451 fatal_f("log fd read: %s", strerror(errno));
452 if ((r = sshbuf_get_u32(logmsg, &level)) != 0 ||
453 (r = sshbuf_get_u32(logmsg, &forced)) != 0 ||
454 (r = sshbuf_get_cstring(logmsg, &msg, NULL)) != 0)
455 fatal_fr(r, "parse");
456
457 /* Log it */
458 if (log_level_name(level) == NULL)
459 fatal_f("invalid log level %u (corrupted message?)", level);
460 sshlogdirect(level, forced, "%s [preauth]", msg);
461
462 sshbuf_free(logmsg);
463 free(msg);
464
465 return 0;
466 }
467
468 static int
monitor_read(struct ssh * ssh,struct monitor * pmonitor,struct mon_table * ent,struct mon_table ** pent)469 monitor_read(struct ssh *ssh, struct monitor *pmonitor, struct mon_table *ent,
470 struct mon_table **pent)
471 {
472 struct sshbuf *m;
473 int r, ret;
474 u_char type;
475 struct pollfd pfd[2];
476
477 for (;;) {
478 memset(&pfd, 0, sizeof(pfd));
479 pfd[0].fd = pmonitor->m_sendfd;
480 pfd[0].events = POLLIN;
481 pfd[1].fd = pmonitor->m_log_recvfd;
482 pfd[1].events = pfd[1].fd == -1 ? 0 : POLLIN;
483 if (poll(pfd, pfd[1].fd == -1 ? 1 : 2, -1) == -1) {
484 if (errno == EINTR || errno == EAGAIN)
485 continue;
486 fatal_f("poll: %s", strerror(errno));
487 }
488 if (pfd[1].revents) {
489 /*
490 * Drain all log messages before processing next
491 * monitor request.
492 */
493 monitor_read_log(pmonitor);
494 continue;
495 }
496 if (pfd[0].revents)
497 break; /* Continues below */
498 }
499
500 if ((m = sshbuf_new()) == NULL)
501 fatal_f("sshbuf_new");
502
503 mm_request_receive(pmonitor->m_sendfd, m);
504 if ((r = sshbuf_get_u8(m, &type)) != 0)
505 fatal_fr(r, "parse type");
506
507 debug3_f("checking request %d", type);
508
509 while (ent->f != NULL) {
510 if (ent->type == type)
511 break;
512 ent++;
513 }
514
515 if (ent->f != NULL) {
516 if (!(ent->flags & MON_PERMIT))
517 fatal_f("unpermitted request %d", type);
518 ret = (*ent->f)(ssh, pmonitor->m_sendfd, m);
519 sshbuf_free(m);
520
521 /* The child may use this request only once, disable it */
522 if (ent->flags & MON_ONCE) {
523 debug2_f("%d used once, disabling now", type);
524 ent->flags &= ~MON_PERMIT;
525 }
526
527 if (pent != NULL)
528 *pent = ent;
529
530 return ret;
531 }
532
533 fatal_f("unsupported request: %d", type);
534
535 /* NOTREACHED */
536 return (-1);
537 }
538
539 /* allowed key state */
540 static int
monitor_allowed_key(const u_char * blob,u_int bloblen)541 monitor_allowed_key(const u_char *blob, u_int bloblen)
542 {
543 /* make sure key is allowed */
544 if (key_blob == NULL || key_bloblen != bloblen ||
545 timingsafe_bcmp(key_blob, blob, key_bloblen))
546 return (0);
547 return (1);
548 }
549
550 static void
monitor_reset_key_state(void)551 monitor_reset_key_state(void)
552 {
553 /* reset state */
554 free(key_blob);
555 free(hostbased_cuser);
556 free(hostbased_chost);
557 sshauthopt_free(key_opts);
558 key_blob = NULL;
559 key_bloblen = 0;
560 key_blobtype = MM_NOKEY;
561 key_opts = NULL;
562 hostbased_cuser = NULL;
563 hostbased_chost = NULL;
564 }
565
566 #ifdef WITH_OPENSSL
567 int
mm_answer_moduli(struct ssh * ssh,int sock,struct sshbuf * m)568 mm_answer_moduli(struct ssh *ssh, int sock, struct sshbuf *m)
569 {
570 DH *dh;
571 const BIGNUM *dh_p, *dh_g;
572 int r;
573 u_int min, want, max;
574
575 if ((r = sshbuf_get_u32(m, &min)) != 0 ||
576 (r = sshbuf_get_u32(m, &want)) != 0 ||
577 (r = sshbuf_get_u32(m, &max)) != 0)
578 fatal_fr(r, "parse");
579
580 debug3_f("got parameters: %d %d %d", min, want, max);
581 /* We need to check here, too, in case the child got corrupted */
582 if (max < min || want < min || max < want)
583 fatal_f("bad parameters: %d %d %d", min, want, max);
584
585 sshbuf_reset(m);
586
587 dh = choose_dh(min, want, max);
588 if (dh == NULL) {
589 if ((r = sshbuf_put_u8(m, 0)) != 0)
590 fatal_fr(r, "assemble empty");
591 return (0);
592 } else {
593 /* Send first bignum */
594 DH_get0_pqg(dh, &dh_p, NULL, &dh_g);
595 if ((r = sshbuf_put_u8(m, 1)) != 0 ||
596 (r = sshbuf_put_bignum2(m, dh_p)) != 0 ||
597 (r = sshbuf_put_bignum2(m, dh_g)) != 0)
598 fatal_fr(r, "assemble");
599
600 DH_free(dh);
601 }
602 mm_request_send(sock, MONITOR_ANS_MODULI, m);
603 return (0);
604 }
605 #endif
606
607 int
mm_answer_sign(struct ssh * ssh,int sock,struct sshbuf * m)608 mm_answer_sign(struct ssh *ssh, int sock, struct sshbuf *m)
609 {
610 extern int auth_sock; /* XXX move to state struct? */
611 struct sshkey *key;
612 struct sshbuf *sigbuf = NULL;
613 u_char *p = NULL, *signature = NULL;
614 char *alg = NULL;
615 size_t datlen, siglen, alglen;
616 int r, is_proof = 0;
617 u_int keyid, compat;
618 const char proof_req[] = "hostkeys-prove-00@openssh.com";
619
620 debug3_f("entering");
621
622 if ((r = sshbuf_get_u32(m, &keyid)) != 0 ||
623 (r = sshbuf_get_string(m, &p, &datlen)) != 0 ||
624 (r = sshbuf_get_cstring(m, &alg, &alglen)) != 0 ||
625 (r = sshbuf_get_u32(m, &compat)) != 0)
626 fatal_fr(r, "parse");
627 if (keyid > INT_MAX)
628 fatal_f("invalid key ID");
629
630 /*
631 * Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes),
632 * SHA384 (48 bytes) and SHA512 (64 bytes).
633 *
634 * Otherwise, verify the signature request is for a hostkey
635 * proof.
636 *
637 * XXX perform similar check for KEX signature requests too?
638 * it's not trivial, since what is signed is the hash, rather
639 * than the full kex structure...
640 */
641 if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64) {
642 /*
643 * Construct expected hostkey proof and compare it to what
644 * the client sent us.
645 */
646 if (session_id2_len == 0) /* hostkeys is never first */
647 fatal_f("bad data length: %zu", datlen);
648 if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL)
649 fatal_f("no hostkey for index %d", keyid);
650 if ((sigbuf = sshbuf_new()) == NULL)
651 fatal_f("sshbuf_new");
652 if ((r = sshbuf_put_cstring(sigbuf, proof_req)) != 0 ||
653 (r = sshbuf_put_string(sigbuf, session_id2,
654 session_id2_len)) != 0 ||
655 (r = sshkey_puts(key, sigbuf)) != 0)
656 fatal_fr(r, "assemble private key proof");
657 if (datlen != sshbuf_len(sigbuf) ||
658 memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0)
659 fatal_f("bad data length: %zu, hostkey proof len %zu",
660 datlen, sshbuf_len(sigbuf));
661 sshbuf_free(sigbuf);
662 is_proof = 1;
663 }
664
665 /* save session id, it will be passed on the first call */
666 if (session_id2_len == 0) {
667 session_id2_len = datlen;
668 session_id2 = xmalloc(session_id2_len);
669 memcpy(session_id2, p, session_id2_len);
670 }
671
672 if ((key = get_hostkey_by_index(keyid)) != NULL) {
673 if ((r = sshkey_sign(key, &signature, &siglen, p, datlen, alg,
674 options.sk_provider, NULL, compat)) != 0)
675 fatal_fr(r, "sign");
676 } else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL &&
677 auth_sock > 0) {
678 if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen,
679 p, datlen, alg, compat)) != 0)
680 fatal_fr(r, "agent sign");
681 } else
682 fatal_f("no hostkey from index %d", keyid);
683
684 debug3_f("%s %s signature len=%zu", alg,
685 is_proof ? "hostkey proof" : "KEX", siglen);
686
687 sshbuf_reset(m);
688 if ((r = sshbuf_put_string(m, signature, siglen)) != 0)
689 fatal_fr(r, "assemble");
690
691 free(alg);
692 free(p);
693 free(signature);
694
695 mm_request_send(sock, MONITOR_ANS_SIGN, m);
696
697 /* Turn on permissions for getpwnam */
698 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1);
699
700 return (0);
701 }
702
703 #define PUTPW(b, id) \
704 do { \
705 if ((r = sshbuf_put_string(b, \
706 &pwent->id, sizeof(pwent->id))) != 0) \
707 fatal_fr(r, "assemble %s", #id); \
708 } while (0)
709
710 /* Retrieves the password entry and also checks if the user is permitted */
711 int
mm_answer_pwnamallow(struct ssh * ssh,int sock,struct sshbuf * m)712 mm_answer_pwnamallow(struct ssh *ssh, int sock, struct sshbuf *m)
713 {
714 struct passwd *pwent;
715 int r, allowed = 0;
716 u_int i;
717
718 debug3_f("entering");
719
720 if (authctxt->attempt++ != 0)
721 fatal_f("multiple attempts for getpwnam");
722
723 if ((r = sshbuf_get_cstring(m, &authctxt->user, NULL)) != 0)
724 fatal_fr(r, "parse");
725
726 pwent = getpwnamallow(ssh, authctxt->user);
727
728 setproctitle("%s [priv]", pwent ? authctxt->user : "unknown");
729
730 sshbuf_reset(m);
731
732 if (pwent == NULL) {
733 if ((r = sshbuf_put_u8(m, 0)) != 0)
734 fatal_fr(r, "assemble fakepw");
735 authctxt->pw = fakepw();
736 goto out;
737 }
738
739 allowed = 1;
740 authctxt->pw = pwent;
741 authctxt->valid = 1;
742
743 /* XXX send fake class/dir/shell, etc. */
744 if ((r = sshbuf_put_u8(m, 1)) != 0)
745 fatal_fr(r, "assemble ok");
746 PUTPW(m, pw_uid);
747 PUTPW(m, pw_gid);
748 #ifdef HAVE_STRUCT_PASSWD_PW_CHANGE
749 PUTPW(m, pw_change);
750 #endif
751 #ifdef HAVE_STRUCT_PASSWD_PW_EXPIRE
752 PUTPW(m, pw_expire);
753 #endif
754 if ((r = sshbuf_put_cstring(m, pwent->pw_name)) != 0 ||
755 (r = sshbuf_put_cstring(m, "*")) != 0 ||
756 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS
757 (r = sshbuf_put_cstring(m, pwent->pw_gecos)) != 0 ||
758 #endif
759 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS
760 (r = sshbuf_put_cstring(m, pwent->pw_class)) != 0 ||
761 #endif
762 (r = sshbuf_put_cstring(m, pwent->pw_dir)) != 0 ||
763 (r = sshbuf_put_cstring(m, pwent->pw_shell)) != 0)
764 fatal_fr(r, "assemble pw");
765
766 out:
767 ssh_packet_set_log_preamble(ssh, "%suser %s",
768 authctxt->valid ? "authenticating" : "invalid ", authctxt->user);
769 if ((r = sshbuf_put_string(m, &options, sizeof(options))) != 0)
770 fatal_fr(r, "assemble options");
771
772 #define M_CP_STROPT(x) do { \
773 if (options.x != NULL && \
774 (r = sshbuf_put_cstring(m, options.x)) != 0) \
775 fatal_fr(r, "assemble %s", #x); \
776 } while (0)
777 #define M_CP_STRARRAYOPT(x, nx) do { \
778 for (i = 0; i < options.nx; i++) { \
779 if ((r = sshbuf_put_cstring(m, options.x[i])) != 0) \
780 fatal_fr(r, "assemble %s", #x); \
781 } \
782 } while (0)
783 /* See comment in servconf.h */
784 COPY_MATCH_STRING_OPTS();
785 #undef M_CP_STROPT
786 #undef M_CP_STRARRAYOPT
787
788 /* Create valid auth method lists */
789 if (auth2_setup_methods_lists(authctxt) != 0) {
790 /*
791 * The monitor will continue long enough to let the child
792 * run to its packet_disconnect(), but it must not allow any
793 * authentication to succeed.
794 */
795 debug_f("no valid authentication method lists");
796 }
797
798 debug3_f("sending MONITOR_ANS_PWNAM: %d", allowed);
799 mm_request_send(sock, MONITOR_ANS_PWNAM, m);
800
801 /* Allow service/style information on the auth context */
802 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1);
803 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1);
804
805 #ifdef USE_PAM
806 if (options.use_pam)
807 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1);
808 #endif
809
810 return (0);
811 }
812
mm_answer_auth2_read_banner(struct ssh * ssh,int sock,struct sshbuf * m)813 int mm_answer_auth2_read_banner(struct ssh *ssh, int sock, struct sshbuf *m)
814 {
815 char *banner;
816 int r;
817
818 sshbuf_reset(m);
819 banner = auth2_read_banner();
820 if ((r = sshbuf_put_cstring(m, banner != NULL ? banner : "")) != 0)
821 fatal_fr(r, "assemble");
822 mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m);
823 free(banner);
824
825 return (0);
826 }
827
828 int
mm_answer_authserv(struct ssh * ssh,int sock,struct sshbuf * m)829 mm_answer_authserv(struct ssh *ssh, int sock, struct sshbuf *m)
830 {
831 int r;
832
833 monitor_permit_authentications(1);
834
835 if ((r = sshbuf_get_cstring(m, &authctxt->service, NULL)) != 0 ||
836 (r = sshbuf_get_cstring(m, &authctxt->style, NULL)) != 0)
837 fatal_fr(r, "parse");
838 debug3_f("service=%s, style=%s", authctxt->service, authctxt->style);
839
840 if (strlen(authctxt->style) == 0) {
841 free(authctxt->style);
842 authctxt->style = NULL;
843 }
844
845 return (0);
846 }
847
848 /*
849 * Check that the key type appears in the supplied pattern list, ignoring
850 * mismatches in the signature algorithm. (Signature algorithm checks are
851 * performed in the unprivileged authentication code).
852 * Returns 1 on success, 0 otherwise.
853 */
854 static int
key_base_type_match(const char * method,const struct sshkey * key,const char * list)855 key_base_type_match(const char *method, const struct sshkey *key,
856 const char *list)
857 {
858 char *s, *l, *ol = xstrdup(list);
859 int found = 0;
860
861 l = ol;
862 for ((s = strsep(&l, ",")); s && *s != '\0'; (s = strsep(&l, ","))) {
863 if (sshkey_type_from_name(s) == key->type) {
864 found = 1;
865 break;
866 }
867 }
868 if (!found) {
869 error("%s key type %s is not in permitted list %s", method,
870 sshkey_ssh_name(key), list);
871 }
872
873 free(ol);
874 return found;
875 }
876
877 int
mm_answer_authpassword(struct ssh * ssh,int sock,struct sshbuf * m)878 mm_answer_authpassword(struct ssh *ssh, int sock, struct sshbuf *m)
879 {
880 static int call_count;
881 char *passwd;
882 int r, authenticated;
883 size_t plen;
884
885 if (!options.password_authentication)
886 fatal_f("password authentication not enabled");
887 if ((r = sshbuf_get_cstring(m, &passwd, &plen)) != 0)
888 fatal_fr(r, "parse");
889 /* Only authenticate if the context is valid */
890 authenticated = options.password_authentication &&
891 auth_password(ssh, passwd);
892 freezero(passwd, plen);
893
894 sshbuf_reset(m);
895 if ((r = sshbuf_put_u32(m, authenticated)) != 0)
896 fatal_fr(r, "assemble");
897 #ifdef USE_PAM
898 if ((r = sshbuf_put_u32(m, sshpam_get_maxtries_reached())) != 0)
899 fatal_fr(r, "assemble PAM");
900 #endif
901
902 debug3("%s: sending result %d", __func__, authenticated);
903 debug3_f("sending result %d", authenticated);
904 mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m);
905
906 call_count++;
907 if (plen == 0 && call_count == 1)
908 auth_method = "none";
909 else
910 auth_method = "password";
911
912 /* Causes monitor loop to terminate if authenticated */
913 return (authenticated);
914 }
915
916 #ifdef BSD_AUTH
917 int
mm_answer_bsdauthquery(struct ssh * ssh,int sock,struct sshbuf * m)918 mm_answer_bsdauthquery(struct ssh *ssh, int sock, struct sshbuf *m)
919 {
920 char *name, *infotxt;
921 u_int numprompts, *echo_on, success;
922 char **prompts;
923 int r;
924
925 if (!options.kbd_interactive_authentication)
926 fatal_f("kbd-int authentication not enabled");
927 success = bsdauth_query(authctxt, &name, &infotxt, &numprompts,
928 &prompts, &echo_on) < 0 ? 0 : 1;
929
930 sshbuf_reset(m);
931 if ((r = sshbuf_put_u32(m, success)) != 0)
932 fatal_fr(r, "assemble");
933 if (success) {
934 if ((r = sshbuf_put_cstring(m, prompts[0])) != 0)
935 fatal_fr(r, "assemble prompt");
936 }
937
938 debug3_f("sending challenge success: %u", success);
939 mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m);
940
941 if (success) {
942 free(name);
943 free(infotxt);
944 free(prompts);
945 free(echo_on);
946 }
947
948 return (0);
949 }
950
951 int
mm_answer_bsdauthrespond(struct ssh * ssh,int sock,struct sshbuf * m)952 mm_answer_bsdauthrespond(struct ssh *ssh, int sock, struct sshbuf *m)
953 {
954 char *response;
955 int r, authok;
956
957 if (!options.kbd_interactive_authentication)
958 fatal_f("kbd-int authentication not enabled");
959 if (authctxt->as == NULL)
960 fatal_f("no bsd auth session");
961
962 if ((r = sshbuf_get_cstring(m, &response, NULL)) != 0)
963 fatal_fr(r, "parse");
964 authok = options.kbd_interactive_authentication &&
965 auth_userresponse(authctxt->as, response, 0);
966 authctxt->as = NULL;
967 debug3_f("<%s> = <%d>", response, authok);
968 free(response);
969
970 sshbuf_reset(m);
971 if ((r = sshbuf_put_u32(m, authok)) != 0)
972 fatal_fr(r, "assemble");
973
974 debug3_f("sending authenticated: %d", authok);
975 mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m);
976
977 auth_method = "keyboard-interactive";
978 auth_submethod = "bsdauth";
979
980 return (authok != 0);
981 }
982 #endif
983
984 #ifdef USE_PAM
985 int
mm_answer_pam_start(struct ssh * ssh,int sock,struct sshbuf * m)986 mm_answer_pam_start(struct ssh *ssh, int sock, struct sshbuf *m)
987 {
988 if (!options.use_pam)
989 fatal("UsePAM not set, but ended up in %s anyway", __func__);
990
991 start_pam(ssh);
992
993 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1);
994 if (options.kbd_interactive_authentication)
995 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_INIT_CTX, 1);
996
997 return (0);
998 }
999
1000 int
mm_answer_pam_account(struct ssh * ssh,int sock,struct sshbuf * m)1001 mm_answer_pam_account(struct ssh *ssh, int sock, struct sshbuf *m)
1002 {
1003 u_int ret;
1004 int r;
1005
1006 if (!options.use_pam)
1007 fatal("%s: PAM not enabled", __func__);
1008
1009 ret = do_pam_account();
1010
1011 if ((r = sshbuf_put_u32(m, ret)) != 0 ||
1012 (r = sshbuf_put_stringb(m, loginmsg)) != 0)
1013 fatal("%s: buffer error: %s", __func__, ssh_err(r));
1014
1015 mm_request_send(sock, MONITOR_ANS_PAM_ACCOUNT, m);
1016
1017 return (ret);
1018 }
1019
1020 static void *sshpam_ctxt, *sshpam_authok;
1021 extern KbdintDevice sshpam_device;
1022
1023 int
mm_answer_pam_init_ctx(struct ssh * ssh,int sock,struct sshbuf * m)1024 mm_answer_pam_init_ctx(struct ssh *ssh, int sock, struct sshbuf *m)
1025 {
1026 u_int ok = 0;
1027 int r;
1028
1029 debug3("%s", __func__);
1030 if (!options.kbd_interactive_authentication)
1031 fatal("%s: kbd-int authentication not enabled", __func__);
1032 if (sshpam_ctxt != NULL)
1033 fatal("%s: already called", __func__);
1034 sshpam_ctxt = (sshpam_device.init_ctx)(authctxt);
1035 sshpam_authok = NULL;
1036 sshbuf_reset(m);
1037 if (sshpam_ctxt != NULL) {
1038 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1);
1039 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_QUERY, 1);
1040 ok = 1;
1041 }
1042 if ((r = sshbuf_put_u32(m, ok)) != 0)
1043 fatal("%s: buffer error: %s", __func__, ssh_err(r));
1044 mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m);
1045 return (0);
1046 }
1047
1048 int
mm_answer_pam_query(struct ssh * ssh,int sock,struct sshbuf * m)1049 mm_answer_pam_query(struct ssh *ssh, int sock, struct sshbuf *m)
1050 {
1051 char *name = NULL, *info = NULL, **prompts = NULL;
1052 u_int i, num = 0, *echo_on = 0;
1053 int r, ret;
1054
1055 debug3("%s", __func__);
1056 sshpam_authok = NULL;
1057 if (sshpam_ctxt == NULL)
1058 fatal("%s: no context", __func__);
1059 ret = (sshpam_device.query)(sshpam_ctxt, &name, &info,
1060 &num, &prompts, &echo_on);
1061 if (ret == 0 && num == 0)
1062 sshpam_authok = sshpam_ctxt;
1063 if (num > 1 || name == NULL || info == NULL)
1064 fatal("sshpam_device.query failed");
1065 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_RESPOND, 1);
1066 sshbuf_reset(m);
1067 if ((r = sshbuf_put_u32(m, ret)) != 0 ||
1068 (r = sshbuf_put_cstring(m, name)) != 0 ||
1069 (r = sshbuf_put_cstring(m, info)) != 0 ||
1070 (r = sshbuf_put_u32(m, sshpam_get_maxtries_reached())) != 0 ||
1071 (r = sshbuf_put_u32(m, num)) != 0)
1072 fatal("%s: buffer error: %s", __func__, ssh_err(r));
1073 free(name);
1074 free(info);
1075 for (i = 0; i < num; ++i) {
1076 if ((r = sshbuf_put_cstring(m, prompts[i])) != 0 ||
1077 (r = sshbuf_put_u32(m, echo_on[i])) != 0)
1078 fatal("%s: buffer error: %s", __func__, ssh_err(r));
1079 free(prompts[i]);
1080 }
1081 free(prompts);
1082 free(echo_on);
1083 auth_method = "keyboard-interactive";
1084 auth_submethod = "pam";
1085 mm_request_send(sock, MONITOR_ANS_PAM_QUERY, m);
1086 return (0);
1087 }
1088
1089 int
mm_answer_pam_respond(struct ssh * ssh,int sock,struct sshbuf * m)1090 mm_answer_pam_respond(struct ssh *ssh, int sock, struct sshbuf *m)
1091 {
1092 char **resp;
1093 u_int i, num;
1094 int r, ret;
1095
1096 debug3("%s", __func__);
1097 if (sshpam_ctxt == NULL)
1098 fatal("%s: no context", __func__);
1099 sshpam_authok = NULL;
1100 if ((r = sshbuf_get_u32(m, &num)) != 0)
1101 fatal("%s: buffer error: %s", __func__, ssh_err(r));
1102 if (num > PAM_MAX_NUM_MSG) {
1103 fatal_f("Too many PAM messages, got %u, expected <= %u",
1104 num, (unsigned)PAM_MAX_NUM_MSG);
1105 }
1106 if (num > 0) {
1107 resp = xcalloc(num, sizeof(char *));
1108 for (i = 0; i < num; ++i) {
1109 if ((r = sshbuf_get_cstring(m, &(resp[i]), NULL)) != 0)
1110 fatal("%s: buffer error: %s",
1111 __func__, ssh_err(r));
1112 }
1113 ret = (sshpam_device.respond)(sshpam_ctxt, num, resp);
1114 for (i = 0; i < num; ++i)
1115 free(resp[i]);
1116 free(resp);
1117 } else {
1118 ret = (sshpam_device.respond)(sshpam_ctxt, num, NULL);
1119 }
1120 sshbuf_reset(m);
1121 if ((r = sshbuf_put_u32(m, ret)) != 0)
1122 fatal("%s: buffer error: %s", __func__, ssh_err(r));
1123 mm_request_send(sock, MONITOR_ANS_PAM_RESPOND, m);
1124 auth_method = "keyboard-interactive";
1125 auth_submethod = "pam";
1126 if (ret == 0)
1127 sshpam_authok = sshpam_ctxt;
1128 return (0);
1129 }
1130
1131 int
mm_answer_pam_free_ctx(struct ssh * ssh,int sock,struct sshbuf * m)1132 mm_answer_pam_free_ctx(struct ssh *ssh, int sock, struct sshbuf *m)
1133 {
1134 int r = sshpam_authok != NULL && sshpam_authok == sshpam_ctxt;
1135
1136 debug3("%s", __func__);
1137 if (sshpam_ctxt == NULL)
1138 fatal("%s: no context", __func__);
1139 (sshpam_device.free_ctx)(sshpam_ctxt);
1140 sshpam_ctxt = sshpam_authok = NULL;
1141 sshbuf_reset(m);
1142 mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m);
1143 /* Allow another attempt */
1144 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_INIT_CTX, 1);
1145 auth_method = "keyboard-interactive";
1146 auth_submethod = "pam";
1147 return r;
1148 }
1149 #endif
1150
1151 int
mm_answer_keyallowed(struct ssh * ssh,int sock,struct sshbuf * m)1152 mm_answer_keyallowed(struct ssh *ssh, int sock, struct sshbuf *m)
1153 {
1154 struct sshkey *key = NULL;
1155 char *cuser, *chost;
1156 u_int pubkey_auth_attempt;
1157 u_int type = 0;
1158 int r, allowed = 0;
1159 struct sshauthopt *opts = NULL;
1160
1161 debug3_f("entering");
1162 if ((r = sshbuf_get_u32(m, &type)) != 0 ||
1163 (r = sshbuf_get_cstring(m, &cuser, NULL)) != 0 ||
1164 (r = sshbuf_get_cstring(m, &chost, NULL)) != 0 ||
1165 (r = sshkey_froms(m, &key)) != 0 ||
1166 (r = sshbuf_get_u32(m, &pubkey_auth_attempt)) != 0)
1167 fatal_fr(r, "parse");
1168
1169 if (key != NULL && authctxt->valid) {
1170 switch (type) {
1171 case MM_USERKEY:
1172 auth_method = "publickey";
1173 if (!options.pubkey_authentication)
1174 break;
1175 if (auth2_key_already_used(authctxt, key))
1176 break;
1177 if (!key_base_type_match(auth_method, key,
1178 options.pubkey_accepted_algos))
1179 break;
1180 allowed = user_key_allowed(ssh, authctxt->pw, key,
1181 pubkey_auth_attempt, &opts);
1182 break;
1183 case MM_HOSTKEY:
1184 auth_method = "hostbased";
1185 if (!options.hostbased_authentication)
1186 break;
1187 if (auth2_key_already_used(authctxt, key))
1188 break;
1189 if (!key_base_type_match(auth_method, key,
1190 options.hostbased_accepted_algos))
1191 break;
1192 allowed = hostbased_key_allowed(ssh, authctxt->pw,
1193 cuser, chost, key);
1194 auth2_record_info(authctxt,
1195 "client user \"%.100s\", client host \"%.100s\"",
1196 cuser, chost);
1197 break;
1198 default:
1199 fatal_f("unknown key type %u", type);
1200 break;
1201 }
1202 }
1203
1204 debug3_f("%s authentication%s: %s key is %s", auth_method,
1205 pubkey_auth_attempt ? "" : " test",
1206 (key == NULL || !authctxt->valid) ? "invalid" : sshkey_type(key),
1207 allowed ? "allowed" : "not allowed");
1208
1209 auth2_record_key(authctxt, 0, key);
1210
1211 /* clear temporarily storage (used by verify) */
1212 monitor_reset_key_state();
1213
1214 if (allowed) {
1215 /* Save temporarily for comparison in verify */
1216 if ((r = sshkey_to_blob(key, &key_blob, &key_bloblen)) != 0)
1217 fatal_fr(r, "sshkey_to_blob");
1218 key_blobtype = type;
1219 key_opts = opts;
1220 hostbased_cuser = cuser;
1221 hostbased_chost = chost;
1222 } else {
1223 /* Log failed attempt */
1224 auth_log(ssh, 0, 0, auth_method, NULL);
1225 free(cuser);
1226 free(chost);
1227 }
1228 sshkey_free(key);
1229
1230 sshbuf_reset(m);
1231 if ((r = sshbuf_put_u32(m, allowed)) != 0)
1232 fatal_fr(r, "assemble");
1233 if (opts != NULL && (r = sshauthopt_serialise(opts, m, 1)) != 0)
1234 fatal_fr(r, "sshauthopt_serialise");
1235 mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m);
1236
1237 if (!allowed)
1238 sshauthopt_free(opts);
1239
1240 return (0);
1241 }
1242
1243 static int
monitor_valid_userblob(struct ssh * ssh,const u_char * data,u_int datalen)1244 monitor_valid_userblob(struct ssh *ssh, const u_char *data, u_int datalen)
1245 {
1246 struct sshbuf *b;
1247 struct sshkey *hostkey = NULL;
1248 const u_char *p;
1249 char *userstyle, *cp;
1250 size_t len;
1251 u_char type;
1252 int hostbound = 0, r, fail = 0;
1253
1254 if ((b = sshbuf_from(data, datalen)) == NULL)
1255 fatal_f("sshbuf_from");
1256
1257 if (ssh->compat & SSH_OLD_SESSIONID) {
1258 p = sshbuf_ptr(b);
1259 len = sshbuf_len(b);
1260 if ((session_id2 == NULL) ||
1261 (len < session_id2_len) ||
1262 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0))
1263 fail++;
1264 if ((r = sshbuf_consume(b, session_id2_len)) != 0)
1265 fatal_fr(r, "consume");
1266 } else {
1267 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0)
1268 fatal_fr(r, "parse sessionid");
1269 if ((session_id2 == NULL) ||
1270 (len != session_id2_len) ||
1271 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0))
1272 fail++;
1273 }
1274 if ((r = sshbuf_get_u8(b, &type)) != 0)
1275 fatal_fr(r, "parse type");
1276 if (type != SSH2_MSG_USERAUTH_REQUEST)
1277 fail++;
1278 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0)
1279 fatal_fr(r, "parse userstyle");
1280 xasprintf(&userstyle, "%s%s%s", authctxt->user,
1281 authctxt->style ? ":" : "",
1282 authctxt->style ? authctxt->style : "");
1283 if (strcmp(userstyle, cp) != 0) {
1284 logit("wrong user name passed to monitor: "
1285 "expected %s != %.100s", userstyle, cp);
1286 fail++;
1287 }
1288 free(userstyle);
1289 free(cp);
1290 if ((r = sshbuf_skip_string(b)) != 0 || /* service */
1291 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0)
1292 fatal_fr(r, "parse method");
1293 if (strcmp("publickey", cp) != 0) {
1294 if (strcmp("publickey-hostbound-v00@openssh.com", cp) == 0)
1295 hostbound = 1;
1296 else
1297 fail++;
1298 }
1299 free(cp);
1300 if ((r = sshbuf_get_u8(b, &type)) != 0)
1301 fatal_fr(r, "parse pktype");
1302 if (type == 0)
1303 fail++;
1304 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */
1305 (r = sshbuf_skip_string(b)) != 0 || /* pkblob */
1306 (hostbound && (r = sshkey_froms(b, &hostkey)) != 0))
1307 fatal_fr(r, "parse pk");
1308 if (sshbuf_len(b) != 0)
1309 fail++;
1310 sshbuf_free(b);
1311 if (hostkey != NULL) {
1312 /*
1313 * Ensure this is actually one of our hostkeys; unfortunately
1314 * can't check ssh->kex->initial_hostkey directly at this point
1315 * as packet state has not yet been exported to monitor.
1316 */
1317 if (get_hostkey_index(hostkey, 1, ssh) == -1)
1318 fatal_f("hostbound hostkey does not match");
1319 sshkey_free(hostkey);
1320 }
1321 return (fail == 0);
1322 }
1323
1324 static int
monitor_valid_hostbasedblob(const u_char * data,u_int datalen,const char * cuser,const char * chost)1325 monitor_valid_hostbasedblob(const u_char *data, u_int datalen,
1326 const char *cuser, const char *chost)
1327 {
1328 struct sshbuf *b;
1329 const u_char *p;
1330 char *cp, *userstyle;
1331 size_t len;
1332 int r, fail = 0;
1333 u_char type;
1334
1335 if ((b = sshbuf_from(data, datalen)) == NULL)
1336 fatal_f("sshbuf_new");
1337 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0)
1338 fatal_fr(r, "parse sessionid");
1339
1340 if ((session_id2 == NULL) ||
1341 (len != session_id2_len) ||
1342 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0))
1343 fail++;
1344
1345 if ((r = sshbuf_get_u8(b, &type)) != 0)
1346 fatal_fr(r, "parse type");
1347 if (type != SSH2_MSG_USERAUTH_REQUEST)
1348 fail++;
1349 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0)
1350 fatal_fr(r, "parse userstyle");
1351 xasprintf(&userstyle, "%s%s%s", authctxt->user,
1352 authctxt->style ? ":" : "",
1353 authctxt->style ? authctxt->style : "");
1354 if (strcmp(userstyle, cp) != 0) {
1355 logit("wrong user name passed to monitor: "
1356 "expected %s != %.100s", userstyle, cp);
1357 fail++;
1358 }
1359 free(userstyle);
1360 free(cp);
1361 if ((r = sshbuf_skip_string(b)) != 0 || /* service */
1362 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0)
1363 fatal_fr(r, "parse method");
1364 if (strcmp(cp, "hostbased") != 0)
1365 fail++;
1366 free(cp);
1367 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */
1368 (r = sshbuf_skip_string(b)) != 0) /* pkblob */
1369 fatal_fr(r, "parse pk");
1370
1371 /* verify client host, strip trailing dot if necessary */
1372 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0)
1373 fatal_fr(r, "parse host");
1374 if (((len = strlen(cp)) > 0) && cp[len - 1] == '.')
1375 cp[len - 1] = '\0';
1376 if (strcmp(cp, chost) != 0)
1377 fail++;
1378 free(cp);
1379
1380 /* verify client user */
1381 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0)
1382 fatal_fr(r, "parse ruser");
1383 if (strcmp(cp, cuser) != 0)
1384 fail++;
1385 free(cp);
1386
1387 if (sshbuf_len(b) != 0)
1388 fail++;
1389 sshbuf_free(b);
1390 return (fail == 0);
1391 }
1392
1393 int
mm_answer_keyverify(struct ssh * ssh,int sock,struct sshbuf * m)1394 mm_answer_keyverify(struct ssh *ssh, int sock, struct sshbuf *m)
1395 {
1396 struct sshkey *key;
1397 const u_char *signature, *data, *blob;
1398 char *sigalg = NULL, *fp = NULL;
1399 size_t signaturelen, datalen, bloblen;
1400 int r, ret, req_presence = 0, req_verify = 0, valid_data = 0;
1401 int encoded_ret;
1402 struct sshkey_sig_details *sig_details = NULL;
1403
1404 if ((r = sshbuf_get_string_direct(m, &blob, &bloblen)) != 0 ||
1405 (r = sshbuf_get_string_direct(m, &signature, &signaturelen)) != 0 ||
1406 (r = sshbuf_get_string_direct(m, &data, &datalen)) != 0 ||
1407 (r = sshbuf_get_cstring(m, &sigalg, NULL)) != 0)
1408 fatal_fr(r, "parse");
1409
1410 if (hostbased_cuser == NULL || hostbased_chost == NULL ||
1411 !monitor_allowed_key(blob, bloblen))
1412 fatal_f("bad key, not previously allowed");
1413
1414 /* Empty signature algorithm means NULL. */
1415 if (*sigalg == '\0') {
1416 free(sigalg);
1417 sigalg = NULL;
1418 }
1419
1420 /* XXX use sshkey_froms here; need to change key_blob, etc. */
1421 if ((r = sshkey_from_blob(blob, bloblen, &key)) != 0)
1422 fatal_fr(r, "parse key");
1423
1424 switch (key_blobtype) {
1425 case MM_USERKEY:
1426 valid_data = monitor_valid_userblob(ssh, data, datalen);
1427 auth_method = "publickey";
1428 break;
1429 case MM_HOSTKEY:
1430 valid_data = monitor_valid_hostbasedblob(data, datalen,
1431 hostbased_cuser, hostbased_chost);
1432 auth_method = "hostbased";
1433 break;
1434 default:
1435 valid_data = 0;
1436 break;
1437 }
1438 if (!valid_data)
1439 fatal_f("bad %s signature data blob",
1440 key_blobtype == MM_USERKEY ? "userkey" :
1441 (key_blobtype == MM_HOSTKEY ? "hostkey" : "unknown"));
1442
1443 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash,
1444 SSH_FP_DEFAULT)) == NULL)
1445 fatal_f("sshkey_fingerprint failed");
1446
1447 ret = sshkey_verify(key, signature, signaturelen, data, datalen,
1448 sigalg, ssh->compat, &sig_details);
1449 debug3_f("%s %s signature using %s %s%s%s", auth_method,
1450 sshkey_type(key), sigalg == NULL ? "default" : sigalg,
1451 (ret == 0) ? "verified" : "unverified",
1452 (ret != 0) ? ": " : "", (ret != 0) ? ssh_err(ret) : "");
1453
1454 if (ret == 0 && key_blobtype == MM_USERKEY && sig_details != NULL) {
1455 req_presence = (options.pubkey_auth_options &
1456 PUBKEYAUTH_TOUCH_REQUIRED) ||
1457 !key_opts->no_require_user_presence;
1458 if (req_presence &&
1459 (sig_details->sk_flags & SSH_SK_USER_PRESENCE_REQD) == 0) {
1460 error("public key %s %s signature for %s%s from %.128s "
1461 "port %d rejected: user presence "
1462 "(authenticator touch) requirement not met ",
1463 sshkey_type(key), fp,
1464 authctxt->valid ? "" : "invalid user ",
1465 authctxt->user, ssh_remote_ipaddr(ssh),
1466 ssh_remote_port(ssh));
1467 ret = SSH_ERR_SIGNATURE_INVALID;
1468 }
1469 req_verify = (options.pubkey_auth_options &
1470 PUBKEYAUTH_VERIFY_REQUIRED) || key_opts->require_verify;
1471 if (req_verify &&
1472 (sig_details->sk_flags & SSH_SK_USER_VERIFICATION_REQD) == 0) {
1473 error("public key %s %s signature for %s%s from %.128s "
1474 "port %d rejected: user verification requirement "
1475 "not met ", sshkey_type(key), fp,
1476 authctxt->valid ? "" : "invalid user ",
1477 authctxt->user, ssh_remote_ipaddr(ssh),
1478 ssh_remote_port(ssh));
1479 ret = SSH_ERR_SIGNATURE_INVALID;
1480 }
1481 }
1482 auth2_record_key(authctxt, ret == 0, key);
1483
1484 if (key_blobtype == MM_USERKEY)
1485 auth_activate_options(ssh, key_opts);
1486 monitor_reset_key_state();
1487
1488 sshbuf_reset(m);
1489
1490 /* encode ret != 0 as positive integer, since we're sending u32 */
1491 encoded_ret = (ret != 0);
1492 if ((r = sshbuf_put_u32(m, encoded_ret)) != 0 ||
1493 (r = sshbuf_put_u8(m, sig_details != NULL)) != 0)
1494 fatal_fr(r, "assemble");
1495 if (sig_details != NULL) {
1496 if ((r = sshbuf_put_u32(m, sig_details->sk_counter)) != 0 ||
1497 (r = sshbuf_put_u8(m, sig_details->sk_flags)) != 0)
1498 fatal_fr(r, "assemble sk");
1499 }
1500 sshkey_sig_details_free(sig_details);
1501 mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m);
1502
1503 free(sigalg);
1504 free(fp);
1505 sshkey_free(key);
1506
1507 return ret == 0;
1508 }
1509
1510 static void
mm_record_login(struct ssh * ssh,Session * s,struct passwd * pw)1511 mm_record_login(struct ssh *ssh, Session *s, struct passwd *pw)
1512 {
1513 socklen_t fromlen;
1514 struct sockaddr_storage from;
1515
1516 /*
1517 * Get IP address of client. If the connection is not a socket, let
1518 * the address be 0.0.0.0.
1519 */
1520 memset(&from, 0, sizeof(from));
1521 fromlen = sizeof(from);
1522 if (ssh_packet_connection_is_on_socket(ssh)) {
1523 if (getpeername(ssh_packet_get_connection_in(ssh),
1524 (struct sockaddr *)&from, &fromlen) == -1) {
1525 debug("getpeername: %.100s", strerror(errno));
1526 cleanup_exit(255);
1527 }
1528 }
1529 /* Record that there was a login on that tty from the remote host. */
1530 record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid,
1531 session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns),
1532 (struct sockaddr *)&from, fromlen);
1533 }
1534
1535 static void
mm_session_close(Session * s)1536 mm_session_close(Session *s)
1537 {
1538 debug3_f("session %d pid %ld", s->self, (long)s->pid);
1539 if (s->ttyfd != -1) {
1540 debug3_f("tty %s ptyfd %d", s->tty, s->ptyfd);
1541 session_pty_cleanup2(s);
1542 }
1543 session_unused(s->self);
1544 }
1545
1546 int
mm_answer_pty(struct ssh * ssh,int sock,struct sshbuf * m)1547 mm_answer_pty(struct ssh *ssh, int sock, struct sshbuf *m)
1548 {
1549 extern struct monitor *pmonitor;
1550 Session *s;
1551 int r, res, fd0;
1552
1553 debug3_f("entering");
1554
1555 sshbuf_reset(m);
1556 s = session_new();
1557 if (s == NULL)
1558 goto error;
1559 s->authctxt = authctxt;
1560 s->pw = authctxt->pw;
1561 s->pid = pmonitor->m_pid;
1562 res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty));
1563 if (res == 0)
1564 goto error;
1565 pty_setowner(authctxt->pw, s->tty);
1566
1567 if ((r = sshbuf_put_u32(m, 1)) != 0 ||
1568 (r = sshbuf_put_cstring(m, s->tty)) != 0)
1569 fatal_fr(r, "assemble");
1570
1571 /* We need to trick ttyslot */
1572 if (dup2(s->ttyfd, 0) == -1)
1573 fatal_f("dup2");
1574
1575 mm_record_login(ssh, s, authctxt->pw);
1576
1577 /* Now we can close the file descriptor again */
1578 close(0);
1579
1580 /* send messages generated by record_login */
1581 if ((r = sshbuf_put_stringb(m, loginmsg)) != 0)
1582 fatal_fr(r, "assemble loginmsg");
1583 sshbuf_reset(loginmsg);
1584
1585 mm_request_send(sock, MONITOR_ANS_PTY, m);
1586
1587 if (mm_send_fd(sock, s->ptyfd) == -1 ||
1588 mm_send_fd(sock, s->ttyfd) == -1)
1589 fatal_f("send fds failed");
1590
1591 /* make sure nothing uses fd 0 */
1592 if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) == -1)
1593 fatal_f("open(/dev/null): %s", strerror(errno));
1594 if (fd0 != 0)
1595 error_f("fd0 %d != 0", fd0);
1596
1597 /* slave side of pty is not needed */
1598 close(s->ttyfd);
1599 s->ttyfd = s->ptyfd;
1600 /* no need to dup() because nobody closes ptyfd */
1601 s->ptymaster = s->ptyfd;
1602
1603 debug3_f("tty %s ptyfd %d", s->tty, s->ttyfd);
1604
1605 return (0);
1606
1607 error:
1608 if (s != NULL)
1609 mm_session_close(s);
1610 if ((r = sshbuf_put_u32(m, 0)) != 0)
1611 fatal_fr(r, "assemble 0");
1612 mm_request_send(sock, MONITOR_ANS_PTY, m);
1613 return (0);
1614 }
1615
1616 int
mm_answer_pty_cleanup(struct ssh * ssh,int sock,struct sshbuf * m)1617 mm_answer_pty_cleanup(struct ssh *ssh, int sock, struct sshbuf *m)
1618 {
1619 Session *s;
1620 char *tty;
1621 int r;
1622
1623 debug3_f("entering");
1624
1625 if ((r = sshbuf_get_cstring(m, &tty, NULL)) != 0)
1626 fatal_fr(r, "parse tty");
1627 if ((s = session_by_tty(tty)) != NULL)
1628 mm_session_close(s);
1629 sshbuf_reset(m);
1630 free(tty);
1631 return (0);
1632 }
1633
1634 int
mm_answer_term(struct ssh * ssh,int sock,struct sshbuf * req)1635 mm_answer_term(struct ssh *ssh, int sock, struct sshbuf *req)
1636 {
1637 extern struct monitor *pmonitor;
1638 int res, status;
1639
1640 debug3_f("tearing down sessions");
1641
1642 /* The child is terminating */
1643 session_destroy_all(ssh, &mm_session_close);
1644
1645 #ifdef USE_PAM
1646 if (options.use_pam)
1647 sshpam_cleanup();
1648 #endif
1649
1650 while (waitpid(pmonitor->m_pid, &status, 0) == -1)
1651 if (errno != EINTR)
1652 exit(1);
1653
1654 res = WIFEXITED(status) ? WEXITSTATUS(status) : 1;
1655
1656 /* Terminate process */
1657 exit(res);
1658 }
1659
1660 #ifdef SSH_AUDIT_EVENTS
1661 /* Report that an audit event occurred */
1662 int
mm_answer_audit_event(struct ssh * ssh,int socket,struct sshbuf * m)1663 mm_answer_audit_event(struct ssh *ssh, int socket, struct sshbuf *m)
1664 {
1665 u_int n;
1666 ssh_audit_event_t event;
1667 int r;
1668
1669 debug3("%s entering", __func__);
1670
1671 if ((r = sshbuf_get_u32(m, &n)) != 0)
1672 fatal("%s: buffer error: %s", __func__, ssh_err(r));
1673 event = (ssh_audit_event_t)n;
1674 switch (event) {
1675 case SSH_AUTH_FAIL_PUBKEY:
1676 case SSH_AUTH_FAIL_HOSTBASED:
1677 case SSH_AUTH_FAIL_GSSAPI:
1678 case SSH_LOGIN_EXCEED_MAXTRIES:
1679 case SSH_LOGIN_ROOT_DENIED:
1680 case SSH_CONNECTION_CLOSE:
1681 case SSH_INVALID_USER:
1682 audit_event(ssh, event);
1683 break;
1684 default:
1685 fatal("Audit event type %d not permitted", event);
1686 }
1687
1688 return (0);
1689 }
1690
1691 int
mm_answer_audit_command(struct ssh * ssh,int socket,struct sshbuf * m)1692 mm_answer_audit_command(struct ssh *ssh, int socket, struct sshbuf *m)
1693 {
1694 char *cmd;
1695 int r;
1696
1697 debug3("%s entering", __func__);
1698 if ((r = sshbuf_get_cstring(m, &cmd, NULL)) != 0)
1699 fatal("%s: buffer error: %s", __func__, ssh_err(r));
1700 /* sanity check command, if so how? */
1701 audit_run_command(cmd);
1702 free(cmd);
1703 return (0);
1704 }
1705 #endif /* SSH_AUDIT_EVENTS */
1706
1707 void
monitor_clear_keystate(struct ssh * ssh,struct monitor * pmonitor)1708 monitor_clear_keystate(struct ssh *ssh, struct monitor *pmonitor)
1709 {
1710 ssh_clear_newkeys(ssh, MODE_IN);
1711 ssh_clear_newkeys(ssh, MODE_OUT);
1712 sshbuf_free(child_state);
1713 child_state = NULL;
1714 }
1715
1716 void
monitor_apply_keystate(struct ssh * ssh,struct monitor * pmonitor)1717 monitor_apply_keystate(struct ssh *ssh, struct monitor *pmonitor)
1718 {
1719 struct kex *kex;
1720 int r;
1721
1722 debug3_f("packet_set_state");
1723 if ((r = ssh_packet_set_state(ssh, child_state)) != 0)
1724 fatal_fr(r, "packet_set_state");
1725 sshbuf_free(child_state);
1726 child_state = NULL;
1727 if ((kex = ssh->kex) == NULL)
1728 fatal_f("internal error: ssh->kex == NULL");
1729 if (session_id2_len != sshbuf_len(ssh->kex->session_id)) {
1730 fatal_f("incorrect session id length %zu (expected %u)",
1731 sshbuf_len(ssh->kex->session_id), session_id2_len);
1732 }
1733 if (memcmp(sshbuf_ptr(ssh->kex->session_id), session_id2,
1734 session_id2_len) != 0)
1735 fatal_f("session ID mismatch");
1736 /* XXX set callbacks */
1737 #ifdef WITH_OPENSSL
1738 kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_server;
1739 kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_server;
1740 kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_server;
1741 kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_server;
1742 kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_server;
1743 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
1744 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
1745 # ifdef OPENSSL_HAS_ECC
1746 kex->kex[KEX_ECDH_SHA2] = kex_gen_server;
1747 # endif
1748 #endif /* WITH_OPENSSL */
1749 kex->kex[KEX_C25519_SHA256] = kex_gen_server;
1750 kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_server;
1751 kex->load_host_public_key=&get_hostkey_public_by_type;
1752 kex->load_host_private_key=&get_hostkey_private_by_type;
1753 kex->host_key_index=&get_hostkey_index;
1754 kex->sign = sshd_hostkey_sign;
1755 }
1756
1757 /* This function requires careful sanity checking */
1758
1759 void
mm_get_keystate(struct ssh * ssh,struct monitor * pmonitor)1760 mm_get_keystate(struct ssh *ssh, struct monitor *pmonitor)
1761 {
1762 debug3_f("Waiting for new keys");
1763
1764 if ((child_state = sshbuf_new()) == NULL)
1765 fatal_f("sshbuf_new failed");
1766 mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT,
1767 child_state);
1768 debug3_f("GOT new keys");
1769 }
1770
1771
1772 /* XXX */
1773
1774 #define FD_CLOSEONEXEC(x) do { \
1775 if (fcntl(x, F_SETFD, FD_CLOEXEC) == -1) \
1776 fatal("fcntl(%d, F_SETFD)", x); \
1777 } while (0)
1778
1779 static void
monitor_openfds(struct monitor * mon,int do_logfds)1780 monitor_openfds(struct monitor *mon, int do_logfds)
1781 {
1782 int pair[2];
1783 #ifdef SO_ZEROIZE
1784 int on = 1;
1785 #endif
1786
1787 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1)
1788 fatal_f("socketpair: %s", strerror(errno));
1789 #ifdef SO_ZEROIZE
1790 if (setsockopt(pair[0], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1)
1791 error("setsockopt SO_ZEROIZE(0): %.100s", strerror(errno));
1792 if (setsockopt(pair[1], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1)
1793 error("setsockopt SO_ZEROIZE(1): %.100s", strerror(errno));
1794 #endif
1795 FD_CLOSEONEXEC(pair[0]);
1796 FD_CLOSEONEXEC(pair[1]);
1797 mon->m_recvfd = pair[0];
1798 mon->m_sendfd = pair[1];
1799
1800 if (do_logfds) {
1801 if (pipe(pair) == -1)
1802 fatal_f("pipe: %s", strerror(errno));
1803 FD_CLOSEONEXEC(pair[0]);
1804 FD_CLOSEONEXEC(pair[1]);
1805 mon->m_log_recvfd = pair[0];
1806 mon->m_log_sendfd = pair[1];
1807 } else
1808 mon->m_log_recvfd = mon->m_log_sendfd = -1;
1809 }
1810
1811 #define MM_MEMSIZE 65536
1812
1813 struct monitor *
monitor_init(void)1814 monitor_init(void)
1815 {
1816 struct monitor *mon;
1817
1818 mon = xcalloc(1, sizeof(*mon));
1819 monitor_openfds(mon, 1);
1820
1821 return mon;
1822 }
1823
1824 void
monitor_reinit(struct monitor * mon)1825 monitor_reinit(struct monitor *mon)
1826 {
1827 monitor_openfds(mon, 0);
1828 }
1829
1830 #ifdef GSSAPI
1831 int
mm_answer_gss_setup_ctx(struct ssh * ssh,int sock,struct sshbuf * m)1832 mm_answer_gss_setup_ctx(struct ssh *ssh, int sock, struct sshbuf *m)
1833 {
1834 gss_OID_desc goid;
1835 OM_uint32 major;
1836 size_t len;
1837 u_char *p;
1838 int r;
1839
1840 if (!options.gss_authentication)
1841 fatal_f("GSSAPI authentication not enabled");
1842
1843 if ((r = sshbuf_get_string(m, &p, &len)) != 0)
1844 fatal_fr(r, "parse");
1845 goid.elements = p;
1846 goid.length = len;
1847
1848 major = ssh_gssapi_server_ctx(&gsscontext, &goid);
1849
1850 free(goid.elements);
1851
1852 sshbuf_reset(m);
1853 if ((r = sshbuf_put_u32(m, major)) != 0)
1854 fatal_fr(r, "assemble");
1855
1856 mm_request_send(sock, MONITOR_ANS_GSSSETUP, m);
1857
1858 /* Now we have a context, enable the step */
1859 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1);
1860
1861 return (0);
1862 }
1863
1864 int
mm_answer_gss_accept_ctx(struct ssh * ssh,int sock,struct sshbuf * m)1865 mm_answer_gss_accept_ctx(struct ssh *ssh, int sock, struct sshbuf *m)
1866 {
1867 gss_buffer_desc in;
1868 gss_buffer_desc out = GSS_C_EMPTY_BUFFER;
1869 OM_uint32 major, minor;
1870 OM_uint32 flags = 0; /* GSI needs this */
1871 int r;
1872
1873 if (!options.gss_authentication)
1874 fatal_f("GSSAPI authentication not enabled");
1875
1876 if ((r = ssh_gssapi_get_buffer_desc(m, &in)) != 0)
1877 fatal_fr(r, "ssh_gssapi_get_buffer_desc");
1878 major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags);
1879 free(in.value);
1880
1881 sshbuf_reset(m);
1882 if ((r = sshbuf_put_u32(m, major)) != 0 ||
1883 (r = sshbuf_put_string(m, out.value, out.length)) != 0 ||
1884 (r = sshbuf_put_u32(m, flags)) != 0)
1885 fatal_fr(r, "assemble");
1886 mm_request_send(sock, MONITOR_ANS_GSSSTEP, m);
1887
1888 gss_release_buffer(&minor, &out);
1889
1890 if (major == GSS_S_COMPLETE) {
1891 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0);
1892 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
1893 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1);
1894 }
1895 return (0);
1896 }
1897
1898 int
mm_answer_gss_checkmic(struct ssh * ssh,int sock,struct sshbuf * m)1899 mm_answer_gss_checkmic(struct ssh *ssh, int sock, struct sshbuf *m)
1900 {
1901 gss_buffer_desc gssbuf, mic;
1902 OM_uint32 ret;
1903 int r;
1904
1905 if (!options.gss_authentication)
1906 fatal_f("GSSAPI authentication not enabled");
1907
1908 if ((r = ssh_gssapi_get_buffer_desc(m, &gssbuf)) != 0 ||
1909 (r = ssh_gssapi_get_buffer_desc(m, &mic)) != 0)
1910 fatal_fr(r, "ssh_gssapi_get_buffer_desc");
1911
1912 ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic);
1913
1914 free(gssbuf.value);
1915 free(mic.value);
1916
1917 sshbuf_reset(m);
1918 if ((r = sshbuf_put_u32(m, ret)) != 0)
1919 fatal_fr(r, "assemble");
1920
1921 mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m);
1922
1923 if (!GSS_ERROR(ret))
1924 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
1925
1926 return (0);
1927 }
1928
1929 int
mm_answer_gss_userok(struct ssh * ssh,int sock,struct sshbuf * m)1930 mm_answer_gss_userok(struct ssh *ssh, int sock, struct sshbuf *m)
1931 {
1932 int r, authenticated;
1933 const char *displayname;
1934
1935 if (!options.gss_authentication)
1936 fatal_f("GSSAPI authentication not enabled");
1937
1938 authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user);
1939
1940 sshbuf_reset(m);
1941 if ((r = sshbuf_put_u32(m, authenticated)) != 0)
1942 fatal_fr(r, "assemble");
1943
1944 debug3_f("sending result %d", authenticated);
1945 mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m);
1946
1947 auth_method = "gssapi-with-mic";
1948
1949 if ((displayname = ssh_gssapi_displayname()) != NULL)
1950 auth2_record_info(authctxt, "%s", displayname);
1951
1952 /* Monitor loop will terminate if authenticated */
1953 return (authenticated);
1954 }
1955 #endif /* GSSAPI */
1956
1957