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1/* $OpenBSD: auth-options.c,v 1.102 2025/09/15 04:38:00 djm Exp $ */
2/*
3 * Copyright (c) 2018 Damien Miller <djm@mindrot.org>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18#include <sys/types.h>
19#include <sys/queue.h>
20
21#include <stdlib.h>
22#include <netdb.h>
23#include <pwd.h>
24#include <string.h>
25#include <stdio.h>
26#include <stdint.h>
27#include <stdarg.h>
28#include <ctype.h>
29#include <limits.h>
30
31#include "xmalloc.h"
32#include "ssherr.h"
33#include "log.h"
34#include "sshbuf.h"
35#include "misc.h"
36#include "sshkey.h"
37#include "match.h"
38#include "ssh2.h"
39#include "auth-options.h"
40
41static int
42dup_strings(char ***dstp, size_t *ndstp, char **src, size_t nsrc)
43{
44 char **dst;
45 size_t i, j;
46
47 *dstp = NULL;
48 *ndstp = 0;
49
50 if (nsrc == 0)
51 return 0;
52 if (nsrc >= SIZE_MAX / sizeof(*src) ||
53 (dst = calloc(nsrc, sizeof(*src))) == NULL)
54 return -1;
55 for (i = 0; i < nsrc; i++) {
56 if ((dst[i] = strdup(src[i])) == NULL) {
57 for (j = 0; j < i; j++)
58 free(dst[j]);
59 free(dst);
60 return -1;
61 }
62 }
63 /* success */
64 *dstp = dst;
65 *ndstp = nsrc;
66 return 0;
67}
68
69#define OPTIONS_CRITICAL 1
70#define OPTIONS_EXTENSIONS 2
71static int
72cert_option_list(struct sshauthopt *opts, struct sshbuf *oblob,
73 u_int which, int crit)
74{
75 char *command, *allowed;
76 char *name = NULL;
77 struct sshbuf *c = NULL, *data = NULL;
78 int r, ret = -1, found;
79
80 if ((c = sshbuf_fromb(oblob)) == NULL) {
81 error_f("sshbuf_fromb failed");
82 goto out;
83 }
84
85 while (sshbuf_len(c) > 0) {
86 sshbuf_free(data);
87 data = NULL;
88 if ((r = sshbuf_get_cstring(c, &name, NULL)) != 0 ||
89 (r = sshbuf_froms(c, &data)) != 0) {
90 error_r(r, "Unable to parse certificate options");
91 goto out;
92 }
93 debug3("found certificate option \"%.100s\" len %zu",
94 name, sshbuf_len(data));
95 found = 0;
96 if ((which & OPTIONS_EXTENSIONS) != 0) {
97 if (strcmp(name, "no-touch-required") == 0) {
98 opts->no_require_user_presence = 1;
99 found = 1;
100 } else if (strcmp(name, "permit-X11-forwarding") == 0) {
101 opts->permit_x11_forwarding_flag = 1;
102 found = 1;
103 } else if (strcmp(name,
104 "permit-agent-forwarding") == 0) {
105 opts->permit_agent_forwarding_flag = 1;
106 found = 1;
107 } else if (strcmp(name,
108 "permit-port-forwarding") == 0) {
109 opts->permit_port_forwarding_flag = 1;
110 found = 1;
111 } else if (strcmp(name, "permit-pty") == 0) {
112 opts->permit_pty_flag = 1;
113 found = 1;
114 } else if (strcmp(name, "permit-user-rc") == 0) {
115 opts->permit_user_rc = 1;
116 found = 1;
117 }
118 }
119 if (!found && (which & OPTIONS_CRITICAL) != 0) {
120 if (strcmp(name, "verify-required") == 0) {
121 opts->require_verify = 1;
122 found = 1;
123 } else if (strcmp(name, "force-command") == 0) {
124 if ((r = sshbuf_get_cstring(data, &command,
125 NULL)) != 0) {
126 error_r(r, "Unable to parse \"%s\" "
127 "section", name);
128 goto out;
129 }
130 if (opts->force_command != NULL) {
131 error("Certificate has multiple "
132 "force-command options");
133 free(command);
134 goto out;
135 }
136 opts->force_command = command;
137 found = 1;
138 } else if (strcmp(name, "source-address") == 0) {
139 if ((r = sshbuf_get_cstring(data, &allowed,
140 NULL)) != 0) {
141 error_r(r, "Unable to parse \"%s\" "
142 "section", name);
143 goto out;
144 }
145 if (opts->required_from_host_cert != NULL) {
146 error("Certificate has multiple "
147 "source-address options");
148 free(allowed);
149 goto out;
150 }
151 /* Check syntax */
152 if (addr_match_cidr_list(NULL, allowed) == -1) {
153 error("Certificate source-address "
154 "contents invalid");
155 free(allowed);
156 goto out;
157 }
158 opts->required_from_host_cert = allowed;
159 found = 1;
160 }
161 }
162
163 if (!found) {
164 if (crit) {
165 error("Certificate critical option \"%s\" "
166 "is not supported", name);
167 goto out;
168 } else {
169 logit("Certificate extension \"%s\" "
170 "is not supported", name);
171 }
172 } else if (sshbuf_len(data) != 0) {
173 error("Certificate option \"%s\" corrupt "
174 "(extra data)", name);
175 goto out;
176 }
177 free(name);
178 name = NULL;
179 }
180 /* successfully parsed all options */
181 ret = 0;
182
183 out:
184 free(name);
185 sshbuf_free(data);
186 sshbuf_free(c);
187 return ret;
188}
189
190struct sshauthopt *
191sshauthopt_new(void)
192{
193 struct sshauthopt *ret;
194
195 if ((ret = calloc(1, sizeof(*ret))) == NULL)
196 return NULL;
197 ret->force_tun_device = -1;
198 return ret;
199}
200
201void
202sshauthopt_free(struct sshauthopt *opts)
203{
204 size_t i;
205
206 if (opts == NULL)
207 return;
208
209 free(opts->cert_principals);
210 free(opts->force_command);
211 free(opts->required_from_host_cert);
212 free(opts->required_from_host_keys);
213
214 for (i = 0; i < opts->nenv; i++)
215 free(opts->env[i]);
216 free(opts->env);
217
218 for (i = 0; i < opts->npermitopen; i++)
219 free(opts->permitopen[i]);
220 free(opts->permitopen);
221
222 for (i = 0; i < opts->npermitlisten; i++)
223 free(opts->permitlisten[i]);
224 free(opts->permitlisten);
225
226 freezero(opts, sizeof(*opts));
227}
228
229struct sshauthopt *
230sshauthopt_new_with_keys_defaults(void)
231{
232 struct sshauthopt *ret = NULL;
233
234 if ((ret = sshauthopt_new()) == NULL)
235 return NULL;
236
237 /* Defaults for authorized_keys flags */
238 ret->permit_port_forwarding_flag = 1;
239 ret->permit_agent_forwarding_flag = 1;
240 ret->permit_x11_forwarding_flag = 1;
241 ret->permit_pty_flag = 1;
242 ret->permit_user_rc = 1;
243 return ret;
244}
245
246/*
247 * Parse and record a permitopen/permitlisten directive.
248 * Return 0 on success. Return -1 on failure and sets *errstrp to error reason.
249 */
250static int
251handle_permit(const char **optsp, int allow_bare_port,
252 char ***permitsp, size_t *npermitsp, const char **errstrp)
253{
254 char *opt, *tmp, *cp, *host, **permits = *permitsp;
255 size_t npermits = *npermitsp;
256 const char *errstr = "unknown error";
257
258 if (npermits > SSH_AUTHOPT_PERMIT_MAX) {
259 *errstrp = "too many permission directives";
260 return -1;
261 }
262 if ((opt = opt_dequote(optsp, &errstr)) == NULL) {
263 return -1;
264 }
265 if (allow_bare_port && strchr(opt, ':') == NULL) {
266 /*
267 * Allow a bare port number in permitlisten to indicate a
268 * listen_host wildcard.
269 */
270 if (asprintf(&tmp, "*:%s", opt) == -1) {
271 free(opt);
272 *errstrp = "memory allocation failed";
273 return -1;
274 }
275 free(opt);
276 opt = tmp;
277 }
278 if ((tmp = strdup(opt)) == NULL) {
279 free(opt);
280 *errstrp = "memory allocation failed";
281 return -1;
282 }
283 cp = tmp;
284 /* validate syntax before recording it. */
285 host = hpdelim2(&cp, NULL);
286 if (host == NULL || strlen(host) >= NI_MAXHOST) {
287 free(tmp);
288 free(opt);
289 *errstrp = "invalid permission hostname";
290 return -1;
291 }
292 /*
293 * don't want to use permitopen_port to avoid
294 * dependency on channels.[ch] here.
295 */
296 if (cp == NULL ||
297 (strcmp(cp, "*") != 0 && a2port(cp) <= 0)) {
298 free(tmp);
299 free(opt);
300 *errstrp = "invalid permission port";
301 return -1;
302 }
303 /* XXX - add streamlocal support */
304 free(tmp);
305 /* Record it */
306 if ((permits = recallocarray(permits, npermits, npermits + 1,
307 sizeof(*permits))) == NULL) {
308 free(opt);
309 /* NB. don't update *permitsp if alloc fails */
310 *errstrp = "memory allocation failed";
311 return -1;
312 }
313 permits[npermits++] = opt;
314 *permitsp = permits;
315 *npermitsp = npermits;
316 return 0;
317}
318
319struct sshauthopt *
320sshauthopt_parse(const char *opts, const char **errstrp)
321{
322 char **oarray, *opt, *cp, *tmp;
323 int r;
324 struct sshauthopt *ret = NULL;
325 const char *errstr = "unknown error";
326 uint64_t valid_before;
327 size_t i, l;
328
329 if (errstrp != NULL)
330 *errstrp = NULL;
331 if ((ret = sshauthopt_new_with_keys_defaults()) == NULL)
332 goto alloc_fail;
333
334 if (opts == NULL)
335 return ret;
336
337 while (*opts && *opts != ' ' && *opts != '\t') {
338 /* flag options */
339 if ((r = opt_flag("restrict", 0, &opts)) != -1) {
340 ret->restricted = 1;
341 ret->permit_port_forwarding_flag = 0;
342 ret->permit_agent_forwarding_flag = 0;
343 ret->permit_x11_forwarding_flag = 0;
344 ret->permit_pty_flag = 0;
345 ret->permit_user_rc = 0;
346 } else if ((r = opt_flag("cert-authority", 0, &opts)) != -1) {
347 ret->cert_authority = r;
348 } else if ((r = opt_flag("port-forwarding", 1, &opts)) != -1) {
349 ret->permit_port_forwarding_flag = r == 1;
350 } else if ((r = opt_flag("agent-forwarding", 1, &opts)) != -1) {
351 ret->permit_agent_forwarding_flag = r == 1;
352 } else if ((r = opt_flag("x11-forwarding", 1, &opts)) != -1) {
353 ret->permit_x11_forwarding_flag = r == 1;
354 } else if ((r = opt_flag("touch-required", 1, &opts)) != -1) {
355 ret->no_require_user_presence = r != 1; /* NB. flip */
356 } else if ((r = opt_flag("verify-required", 1, &opts)) != -1) {
357 ret->require_verify = r == 1;
358 } else if ((r = opt_flag("pty", 1, &opts)) != -1) {
359 ret->permit_pty_flag = r == 1;
360 } else if ((r = opt_flag("user-rc", 1, &opts)) != -1) {
361 ret->permit_user_rc = r == 1;
362 } else if (opt_match(&opts, "command")) {
363 if (ret->force_command != NULL) {
364 errstr = "multiple \"command\" clauses";
365 goto fail;
366 }
367 ret->force_command = opt_dequote(&opts, &errstr);
368 if (ret->force_command == NULL)
369 goto fail;
370 } else if (opt_match(&opts, "principals")) {
371 if (ret->cert_principals != NULL) {
372 errstr = "multiple \"principals\" clauses";
373 goto fail;
374 }
375 ret->cert_principals = opt_dequote(&opts, &errstr);
376 if (ret->cert_principals == NULL)
377 goto fail;
378 } else if (opt_match(&opts, "from")) {
379 if (ret->required_from_host_keys != NULL) {
380 errstr = "multiple \"from\" clauses";
381 goto fail;
382 }
383 ret->required_from_host_keys = opt_dequote(&opts,
384 &errstr);
385 if (ret->required_from_host_keys == NULL)
386 goto fail;
387 } else if (opt_match(&opts, "expiry-time")) {
388 if ((opt = opt_dequote(&opts, &errstr)) == NULL)
389 goto fail;
390 if (parse_absolute_time(opt, &valid_before) != 0 ||
391 valid_before == 0) {
392 free(opt);
393 errstr = "invalid expires time";
394 goto fail;
395 }
396 free(opt);
397 if (ret->valid_before == 0 ||
398 valid_before < ret->valid_before)
399 ret->valid_before = valid_before;
400 } else if (opt_match(&opts, "environment")) {
401 if (ret->nenv > SSH_AUTHOPT_ENV_MAX) {
402 errstr = "too many environment strings";
403 goto fail;
404 }
405 if ((opt = opt_dequote(&opts, &errstr)) == NULL)
406 goto fail;
407 /* env name must be alphanumeric and followed by '=' */
408 if ((tmp = strchr(opt, '=')) == NULL) {
409 free(opt);
410 errstr = "invalid environment string";
411 goto fail;
412 }
413 if ((cp = strdup(opt)) == NULL) {
414 free(opt);
415 goto alloc_fail;
416 }
417 l = (size_t)(tmp - opt);
418 cp[l] = '\0'; /* truncate at '=' */
419 if (!valid_env_name(cp)) {
420 free(cp);
421 free(opt);
422 errstr = "invalid environment string";
423 goto fail;
424 }
425 /* Check for duplicates; XXX O(n*log(n)) */
426 for (i = 0; i < ret->nenv; i++) {
427 if (strncmp(ret->env[i], cp, l) == 0 &&
428 ret->env[i][l] == '=')
429 break;
430 }
431 free(cp);
432 /* First match wins */
433 if (i >= ret->nenv) {
434 /* Append it. */
435 oarray = ret->env;
436 if ((ret->env = recallocarray(ret->env,
437 ret->nenv, ret->nenv + 1,
438 sizeof(*ret->env))) == NULL) {
439 free(opt);
440 /* put it back for cleanup */
441 ret->env = oarray;
442 goto alloc_fail;
443 }
444 ret->env[ret->nenv++] = opt;
445 opt = NULL; /* transferred */
446 }
447 free(opt);
448 } else if (opt_match(&opts, "permitopen")) {
449 if (handle_permit(&opts, 0, &ret->permitopen,
450 &ret->npermitopen, &errstr) != 0)
451 goto fail;
452 } else if (opt_match(&opts, "permitlisten")) {
453 if (handle_permit(&opts, 1, &ret->permitlisten,
454 &ret->npermitlisten, &errstr) != 0)
455 goto fail;
456 } else if (opt_match(&opts, "tunnel")) {
457 if ((opt = opt_dequote(&opts, &errstr)) == NULL)
458 goto fail;
459 ret->force_tun_device = a2tun(opt, NULL);
460 free(opt);
461 if (ret->force_tun_device == SSH_TUNID_ERR) {
462 errstr = "invalid tun device";
463 goto fail;
464 }
465 }
466 /*
467 * Skip the comma, and move to the next option
468 * (or break out if there are no more).
469 */
470 if (*opts == '\0' || *opts == ' ' || *opts == '\t')
471 break; /* End of options. */
472 /* Anything other than a comma is an unknown option */
473 if (*opts != ',') {
474 errstr = "unknown key option";
475 goto fail;
476 }
477 opts++;
478 if (*opts == '\0') {
479 errstr = "unexpected end-of-options";
480 goto fail;
481 }
482 }
483
484 /* success */
485 if (errstrp != NULL)
486 *errstrp = NULL;
487 return ret;
488
489alloc_fail:
490 errstr = "memory allocation failed";
491fail:
492 sshauthopt_free(ret);
493 if (errstrp != NULL)
494 *errstrp = errstr;
495 return NULL;
496}
497
498struct sshauthopt *
499sshauthopt_from_cert(struct sshkey *k)
500{
501 struct sshauthopt *ret;
502
503 if (k == NULL || !sshkey_type_is_cert(k->type) || k->cert == NULL ||
504 k->cert->type != SSH2_CERT_TYPE_USER)
505 return NULL;
506
507 if ((ret = sshauthopt_new()) == NULL)
508 return NULL;
509
510 /* Handle options and critical extensions separately */
511 if (cert_option_list(ret, k->cert->critical,
512 OPTIONS_CRITICAL, 1) == -1) {
513 sshauthopt_free(ret);
514 return NULL;
515 }
516 if (cert_option_list(ret, k->cert->extensions,
517 OPTIONS_EXTENSIONS, 0) == -1) {
518 sshauthopt_free(ret);
519 return NULL;
520 }
521 /* success */
522 return ret;
523}
524
525/*
526 * Merges "additional" options to "primary" and returns the result.
527 * NB. Some options from primary have primacy.
528 */
529struct sshauthopt *
530sshauthopt_merge(const struct sshauthopt *primary,
531 const struct sshauthopt *additional, const char **errstrp)
532{
533 struct sshauthopt *ret;
534 const char *errstr = "internal error";
535 const char *tmp;
536
537 if (errstrp != NULL)
538 *errstrp = NULL;
539
540 if ((ret = sshauthopt_new()) == NULL)
541 goto alloc_fail;
542
543 /* cert_authority and cert_principals are cleared in result */
544
545 /* Prefer access lists from primary. */
546 /* XXX err is both set and mismatch? */
547 tmp = primary->required_from_host_cert;
548 if (tmp == NULL)
549 tmp = additional->required_from_host_cert;
550 if (tmp != NULL && (ret->required_from_host_cert = strdup(tmp)) == NULL)
551 goto alloc_fail;
552 tmp = primary->required_from_host_keys;
553 if (tmp == NULL)
554 tmp = additional->required_from_host_keys;
555 if (tmp != NULL && (ret->required_from_host_keys = strdup(tmp)) == NULL)
556 goto alloc_fail;
557
558 /*
559 * force_tun_device, permitopen/permitlisten and environment all
560 * prefer the primary.
561 */
562 ret->force_tun_device = primary->force_tun_device;
563 if (ret->force_tun_device == -1)
564 ret->force_tun_device = additional->force_tun_device;
565 if (primary->nenv > 0) {
566 if (dup_strings(&ret->env, &ret->nenv,
567 primary->env, primary->nenv) != 0)
568 goto alloc_fail;
569 } else if (additional->nenv) {
570 if (dup_strings(&ret->env, &ret->nenv,
571 additional->env, additional->nenv) != 0)
572 goto alloc_fail;
573 }
574 if (primary->npermitopen > 0) {
575 if (dup_strings(&ret->permitopen, &ret->npermitopen,
576 primary->permitopen, primary->npermitopen) != 0)
577 goto alloc_fail;
578 } else if (additional->npermitopen > 0) {
579 if (dup_strings(&ret->permitopen, &ret->npermitopen,
580 additional->permitopen, additional->npermitopen) != 0)
581 goto alloc_fail;
582 }
583
584 if (primary->npermitlisten > 0) {
585 if (dup_strings(&ret->permitlisten, &ret->npermitlisten,
586 primary->permitlisten, primary->npermitlisten) != 0)
587 goto alloc_fail;
588 } else if (additional->npermitlisten > 0) {
589 if (dup_strings(&ret->permitlisten, &ret->npermitlisten,
590 additional->permitlisten, additional->npermitlisten) != 0)
591 goto alloc_fail;
592 }
593
594#define OPTFLAG_AND(x) ret->x = (primary->x == 1) && (additional->x == 1)
595#define OPTFLAG_OR(x) ret->x = (primary->x == 1) || (additional->x == 1)
596 /* Permissive flags are logical-AND (i.e. must be set in both) */
597 OPTFLAG_AND(permit_port_forwarding_flag);
598 OPTFLAG_AND(permit_agent_forwarding_flag);
599 OPTFLAG_AND(permit_x11_forwarding_flag);
600 OPTFLAG_AND(permit_pty_flag);
601 OPTFLAG_AND(permit_user_rc);
602 OPTFLAG_AND(no_require_user_presence);
603 /* Restrictive flags are logical-OR (i.e. must be set in either) */
604 OPTFLAG_OR(require_verify);
605#undef OPTFLAG_AND
606
607 /* Earliest expiry time should win */
608 if (primary->valid_before != 0)
609 ret->valid_before = primary->valid_before;
610 if (additional->valid_before != 0 &&
611 additional->valid_before < ret->valid_before)
612 ret->valid_before = additional->valid_before;
613
614 /*
615 * When both multiple forced-command are specified, only
616 * proceed if they are identical, otherwise fail.
617 */
618 if (primary->force_command != NULL &&
619 additional->force_command != NULL) {
620 if (strcmp(primary->force_command,
621 additional->force_command) == 0) {
622 /* ok */
623 ret->force_command = strdup(primary->force_command);
624 if (ret->force_command == NULL)
625 goto alloc_fail;
626 } else {
627 errstr = "forced command options do not match";
628 goto fail;
629 }
630 } else if (primary->force_command != NULL) {
631 if ((ret->force_command = strdup(
632 primary->force_command)) == NULL)
633 goto alloc_fail;
634 } else if (additional->force_command != NULL) {
635 if ((ret->force_command = strdup(
636 additional->force_command)) == NULL)
637 goto alloc_fail;
638 }
639 /* success */
640 if (errstrp != NULL)
641 *errstrp = NULL;
642 return ret;
643
644 alloc_fail:
645 errstr = "memory allocation failed";
646 fail:
647 if (errstrp != NULL)
648 *errstrp = errstr;
649 sshauthopt_free(ret);
650 return NULL;
651}
652
653/*
654 * Copy options
655 */
656struct sshauthopt *
657sshauthopt_copy(const struct sshauthopt *orig)
658{
659 struct sshauthopt *ret;
660
661 if ((ret = sshauthopt_new()) == NULL)
662 return NULL;
663
664#define OPTSCALAR(x) ret->x = orig->x
665 OPTSCALAR(permit_port_forwarding_flag);
666 OPTSCALAR(permit_agent_forwarding_flag);
667 OPTSCALAR(permit_x11_forwarding_flag);
668 OPTSCALAR(permit_pty_flag);
669 OPTSCALAR(permit_user_rc);
670 OPTSCALAR(restricted);
671 OPTSCALAR(cert_authority);
672 OPTSCALAR(force_tun_device);
673 OPTSCALAR(valid_before);
674 OPTSCALAR(no_require_user_presence);
675 OPTSCALAR(require_verify);
676#undef OPTSCALAR
677#define OPTSTRING(x) \
678 do { \
679 if (orig->x != NULL && (ret->x = strdup(orig->x)) == NULL) { \
680 sshauthopt_free(ret); \
681 return NULL; \
682 } \
683 } while (0)
684 OPTSTRING(cert_principals);
685 OPTSTRING(force_command);
686 OPTSTRING(required_from_host_cert);
687 OPTSTRING(required_from_host_keys);
688#undef OPTSTRING
689
690 if (dup_strings(&ret->env, &ret->nenv, orig->env, orig->nenv) != 0 ||
691 dup_strings(&ret->permitopen, &ret->npermitopen,
692 orig->permitopen, orig->npermitopen) != 0 ||
693 dup_strings(&ret->permitlisten, &ret->npermitlisten,
694 orig->permitlisten, orig->npermitlisten) != 0) {
695 sshauthopt_free(ret);
696 return NULL;
697 }
698 return ret;
699}
700
701static int
702serialise_array(struct sshbuf *m, char **a, size_t n)
703{
704 struct sshbuf *b;
705 size_t i;
706 int r = SSH_ERR_INTERNAL_ERROR;
707
708 if (n > INT_MAX)
709 return SSH_ERR_INTERNAL_ERROR;
710
711 if ((b = sshbuf_new()) == NULL) {
712 return SSH_ERR_ALLOC_FAIL;
713 }
714 for (i = 0; i < n; i++) {
715 if ((r = sshbuf_put_cstring(b, a[i])) != 0)
716 goto out;
717 }
718 if ((r = sshbuf_put_u32(m, n)) != 0 ||
719 (r = sshbuf_put_stringb(m, b)) != 0)
720 goto out;
721 /* success */
722 r = 0;
723 out:
724 sshbuf_free(b);
725 return r;
726}
727
728static int
729deserialise_array(struct sshbuf *m, char ***ap, size_t *np)
730{
731 char **a = NULL;
732 size_t i, n = 0;
733 struct sshbuf *b = NULL;
734 u_int tmp;
735 int r = SSH_ERR_INTERNAL_ERROR;
736
737 if ((r = sshbuf_get_u32(m, &tmp)) != 0 ||
738 (r = sshbuf_froms(m, &b)) != 0)
739 goto out;
740 if (tmp > INT_MAX) {
741 r = SSH_ERR_INVALID_FORMAT;
742 goto out;
743 }
744 n = tmp;
745 if (n > 0 && (a = calloc(n, sizeof(*a))) == NULL) {
746 r = SSH_ERR_ALLOC_FAIL;
747 goto out;
748 }
749 for (i = 0; i < n; i++) {
750 if ((r = sshbuf_get_cstring(b, &a[i], NULL)) != 0)
751 goto out;
752 }
753 /* success */
754 r = 0;
755 *ap = a;
756 a = NULL;
757 *np = n;
758 n = 0;
759 out:
760 if (a != NULL) {
761 for (i = 0; i < n; i++)
762 free(a[i]);
763 free(a);
764 }
765 sshbuf_free(b);
766 return r;
767}
768
769static int
770serialise_nullable_string(struct sshbuf *m, const char *s)
771{
772 int r;
773
774 if ((r = sshbuf_put_u8(m, s == NULL)) != 0 ||
775 (r = sshbuf_put_cstring(m, s)) != 0)
776 return r;
777 return 0;
778}
779
780static int
781deserialise_nullable_string(struct sshbuf *m, char **sp)
782{
783 int r;
784 u_char flag;
785
786 *sp = NULL;
787 if ((r = sshbuf_get_u8(m, &flag)) != 0 ||
788 (r = sshbuf_get_cstring(m, flag ? NULL : sp, NULL)) != 0)
789 return r;
790 return 0;
791}
792
793int
794sshauthopt_serialise(const struct sshauthopt *opts, struct sshbuf *m,
795 int untrusted)
796{
797 int r = SSH_ERR_INTERNAL_ERROR;
798
799 /* Flag options */
800 if ((r = sshbuf_put_u8(m, opts->permit_port_forwarding_flag)) != 0 ||
801 (r = sshbuf_put_u8(m, opts->permit_agent_forwarding_flag)) != 0 ||
802 (r = sshbuf_put_u8(m, opts->permit_x11_forwarding_flag)) != 0 ||
803 (r = sshbuf_put_u8(m, opts->permit_pty_flag)) != 0 ||
804 (r = sshbuf_put_u8(m, opts->permit_user_rc)) != 0 ||
805 (r = sshbuf_put_u8(m, opts->restricted)) != 0 ||
806 (r = sshbuf_put_u8(m, opts->cert_authority)) != 0 ||
807 (r = sshbuf_put_u8(m, opts->no_require_user_presence)) != 0 ||
808 (r = sshbuf_put_u8(m, opts->require_verify)) != 0)
809 return r;
810
811 /* Simple integer options */
812 if ((r = sshbuf_put_u64(m, opts->valid_before)) != 0)
813 return r;
814
815 /* tunnel number can be negative to indicate "unset" */
816 if ((r = sshbuf_put_u8(m, opts->force_tun_device == -1)) != 0 ||
817 (r = sshbuf_put_u32(m, (opts->force_tun_device < 0) ?
818 0 : (u_int)opts->force_tun_device)) != 0)
819 return r;
820
821 /* String options; these may be NULL */
822 if ((r = serialise_nullable_string(m,
823 untrusted ? "yes" : opts->cert_principals)) != 0 ||
824 (r = serialise_nullable_string(m,
825 untrusted ? "true" : opts->force_command)) != 0 ||
826 (r = serialise_nullable_string(m,
827 untrusted ? NULL : opts->required_from_host_cert)) != 0 ||
828 (r = serialise_nullable_string(m,
829 untrusted ? NULL : opts->required_from_host_keys)) != 0)
830 return r;
831
832 /* Array options */
833 if ((r = serialise_array(m, opts->env,
834 untrusted ? 0 : opts->nenv)) != 0 ||
835 (r = serialise_array(m, opts->permitopen,
836 untrusted ? 0 : opts->npermitopen)) != 0 ||
837 (r = serialise_array(m, opts->permitlisten,
838 untrusted ? 0 : opts->npermitlisten)) != 0)
839 return r;
840
841 /* success */
842 return 0;
843}
844
845int
846sshauthopt_deserialise(struct sshbuf *m, struct sshauthopt **optsp)
847{
848 struct sshauthopt *opts = NULL;
849 int r = SSH_ERR_INTERNAL_ERROR;
850 u_char f;
851 u_int tmp;
852
853 if ((opts = calloc(1, sizeof(*opts))) == NULL)
854 return SSH_ERR_ALLOC_FAIL;
855
856 /* Flag options */
857#define OPT_FLAG(x) \
858 do { \
859 if ((r = sshbuf_get_u8(m, &f)) != 0) \
860 goto out; \
861 opts->x = f; \
862 } while (0)
863 OPT_FLAG(permit_port_forwarding_flag);
864 OPT_FLAG(permit_agent_forwarding_flag);
865 OPT_FLAG(permit_x11_forwarding_flag);
866 OPT_FLAG(permit_pty_flag);
867 OPT_FLAG(permit_user_rc);
868 OPT_FLAG(restricted);
869 OPT_FLAG(cert_authority);
870 OPT_FLAG(no_require_user_presence);
871 OPT_FLAG(require_verify);
872#undef OPT_FLAG
873
874 /* Simple integer options */
875 if ((r = sshbuf_get_u64(m, &opts->valid_before)) != 0)
876 goto out;
877
878 /* tunnel number can be negative to indicate "unset" */
879 if ((r = sshbuf_get_u8(m, &f)) != 0 ||
880 (r = sshbuf_get_u32(m, &tmp)) != 0)
881 goto out;
882 opts->force_tun_device = f ? -1 : (int)tmp;
883
884 /* String options may be NULL */
885 if ((r = deserialise_nullable_string(m, &opts->cert_principals)) != 0 ||
886 (r = deserialise_nullable_string(m, &opts->force_command)) != 0 ||
887 (r = deserialise_nullable_string(m,
888 &opts->required_from_host_cert)) != 0 ||
889 (r = deserialise_nullable_string(m,
890 &opts->required_from_host_keys)) != 0)
891 goto out;
892
893 /* Array options */
894 if ((r = deserialise_array(m, &opts->env, &opts->nenv)) != 0 ||
895 (r = deserialise_array(m,
896 &opts->permitopen, &opts->npermitopen)) != 0 ||
897 (r = deserialise_array(m,
898 &opts->permitlisten, &opts->npermitlisten)) != 0)
899 goto out;
900
901 /* success */
902 r = 0;
903 *optsp = opts;
904 opts = NULL;
905 out:
906 sshauthopt_free(opts);
907 return r;
908}