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1.88 ! djm 1: /* $OpenBSD: auth-options.c,v 1.87 2019/09/03 08:32:11 djm Exp $ */
1.75 djm 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: */
1.3 deraadt 17:
1.36 stevesk 18: #include <sys/types.h>
1.42 djm 19: #include <sys/queue.h>
1.36 stevesk 20:
1.88 ! djm 21: #include <stdlib.h>
1.37 stevesk 22: #include <netdb.h>
1.36 stevesk 23: #include <pwd.h>
1.39 stevesk 24: #include <string.h>
1.40 deraadt 25: #include <stdio.h>
26: #include <stdarg.h>
1.75 djm 27: #include <ctype.h>
28: #include <limits.h>
1.1 markus 29:
30: #include "xmalloc.h"
1.65 markus 31: #include "ssherr.h"
1.11 markus 32: #include "log.h"
1.65 markus 33: #include "sshbuf.h"
1.64 millert 34: #include "misc.h"
1.65 markus 35: #include "sshkey.h"
1.76 djm 36: #include "match.h"
37: #include "ssh2.h"
1.50 djm 38: #include "auth-options.h"
1.75 djm 39:
40: static int
41: dup_strings(char ***dstp, size_t *ndstp, char **src, size_t nsrc)
42: {
43: char **dst;
44: size_t i, j;
45:
46: *dstp = NULL;
47: *ndstp = 0;
48: if (nsrc == 0)
49: return 0;
50:
51: if ((dst = calloc(nsrc, sizeof(*src))) == NULL)
52: return -1;
53: for (i = 0; i < nsrc; i++) {
54: if ((dst[i] = strdup(src[i])) == NULL) {
55: for (j = 0; j < i; j++)
56: free(dst[j]);
57: free(dst);
58: return -1;
59: }
60: }
61: /* success */
62: *dstp = dst;
63: *ndstp = nsrc;
64: return 0;
65: }
66:
67: #define OPTIONS_CRITICAL 1
68: #define OPTIONS_EXTENSIONS 2
69: static int
70: cert_option_list(struct sshauthopt *opts, struct sshbuf *oblob,
71: u_int which, int crit)
72: {
73: char *command, *allowed;
74: char *name = NULL;
75: struct sshbuf *c = NULL, *data = NULL;
76: int r, ret = -1, found;
77:
78: if ((c = sshbuf_fromb(oblob)) == NULL) {
79: error("%s: sshbuf_fromb failed", __func__);
80: goto out;
81: }
82:
83: while (sshbuf_len(c) > 0) {
84: sshbuf_free(data);
85: data = NULL;
86: if ((r = sshbuf_get_cstring(c, &name, NULL)) != 0 ||
87: (r = sshbuf_froms(c, &data)) != 0) {
88: error("Unable to parse certificate options: %s",
89: ssh_err(r));
90: goto out;
91: }
92: debug3("found certificate option \"%.100s\" len %zu",
93: name, sshbuf_len(data));
94: found = 0;
95: if ((which & OPTIONS_EXTENSIONS) != 0) {
96: if (strcmp(name, "permit-X11-forwarding") == 0) {
97: opts->permit_x11_forwarding_flag = 1;
98: found = 1;
99: } else if (strcmp(name,
100: "permit-agent-forwarding") == 0) {
101: opts->permit_agent_forwarding_flag = 1;
102: found = 1;
103: } else if (strcmp(name,
104: "permit-port-forwarding") == 0) {
105: opts->permit_port_forwarding_flag = 1;
106: found = 1;
107: } else if (strcmp(name, "permit-pty") == 0) {
108: opts->permit_pty_flag = 1;
109: found = 1;
110: } else if (strcmp(name, "permit-user-rc") == 0) {
111: opts->permit_user_rc = 1;
112: found = 1;
113: }
114: }
115: if (!found && (which & OPTIONS_CRITICAL) != 0) {
116: if (strcmp(name, "force-command") == 0) {
117: if ((r = sshbuf_get_cstring(data, &command,
118: NULL)) != 0) {
119: error("Unable to parse \"%s\" "
120: "section: %s", name, ssh_err(r));
121: goto out;
122: }
123: if (opts->force_command != NULL) {
124: error("Certificate has multiple "
125: "force-command options");
126: free(command);
127: goto out;
128: }
129: opts->force_command = command;
130: found = 1;
131: }
132: if (strcmp(name, "source-address") == 0) {
133: if ((r = sshbuf_get_cstring(data, &allowed,
134: NULL)) != 0) {
135: error("Unable to parse \"%s\" "
136: "section: %s", name, ssh_err(r));
137: goto out;
138: }
139: if (opts->required_from_host_cert != NULL) {
140: error("Certificate has multiple "
141: "source-address options");
142: free(allowed);
143: goto out;
144: }
145: /* Check syntax */
146: if (addr_match_cidr_list(NULL, allowed) == -1) {
147: error("Certificate source-address "
148: "contents invalid");
149: goto out;
150: }
151: opts->required_from_host_cert = allowed;
152: found = 1;
153: }
154: }
155:
156: if (!found) {
157: if (crit) {
158: error("Certificate critical option \"%s\" "
159: "is not supported", name);
160: goto out;
161: } else {
162: logit("Certificate extension \"%s\" "
163: "is not supported", name);
164: }
165: } else if (sshbuf_len(data) != 0) {
166: error("Certificate option \"%s\" corrupt "
167: "(extra data)", name);
168: goto out;
169: }
170: free(name);
171: name = NULL;
172: }
173: /* successfully parsed all options */
174: ret = 0;
175:
176: out:
177: free(name);
178: sshbuf_free(data);
179: sshbuf_free(c);
180: return ret;
181: }
182:
183: struct sshauthopt *
184: sshauthopt_new(void)
185: {
186: struct sshauthopt *ret;
187:
188: if ((ret = calloc(1, sizeof(*ret))) == NULL)
189: return NULL;
190: ret->force_tun_device = -1;
191: return ret;
192: }
193:
194: void
195: sshauthopt_free(struct sshauthopt *opts)
196: {
197: size_t i;
198:
199: if (opts == NULL)
200: return;
201:
202: free(opts->cert_principals);
203: free(opts->force_command);
204: free(opts->required_from_host_cert);
205: free(opts->required_from_host_keys);
206:
207: for (i = 0; i < opts->nenv; i++)
208: free(opts->env[i]);
209: free(opts->env);
210:
211: for (i = 0; i < opts->npermitopen; i++)
212: free(opts->permitopen[i]);
213: free(opts->permitopen);
214:
1.80 djm 215: for (i = 0; i < opts->npermitlisten; i++)
216: free(opts->permitlisten[i]);
217: free(opts->permitlisten);
218:
1.75 djm 219: explicit_bzero(opts, sizeof(*opts));
220: free(opts);
221: }
222:
223: struct sshauthopt *
224: sshauthopt_new_with_keys_defaults(void)
225: {
226: struct sshauthopt *ret = NULL;
227:
228: if ((ret = sshauthopt_new()) == NULL)
229: return NULL;
230:
231: /* Defaults for authorized_keys flags */
232: ret->permit_port_forwarding_flag = 1;
233: ret->permit_agent_forwarding_flag = 1;
234: ret->permit_x11_forwarding_flag = 1;
235: ret->permit_pty_flag = 1;
236: ret->permit_user_rc = 1;
237: return ret;
238: }
239:
1.80 djm 240: /*
241: * Parse and record a permitopen/permitlisten directive.
242: * Return 0 on success. Return -1 on failure and sets *errstrp to error reason.
243: */
244: static int
1.83 djm 245: handle_permit(const char **optsp, int allow_bare_port,
246: char ***permitsp, size_t *npermitsp, const char **errstrp)
1.80 djm 247: {
248: char *opt, *tmp, *cp, *host, **permits = *permitsp;
249: size_t npermits = *npermitsp;
250: const char *errstr = "unknown error";
251:
1.86 djm 252: if (npermits > SSH_AUTHOPT_PERMIT_MAX) {
1.80 djm 253: *errstrp = "too many permission directives";
254: return -1;
255: }
1.82 djm 256: if ((opt = opt_dequote(optsp, &errstr)) == NULL) {
1.80 djm 257: return -1;
258: }
1.83 djm 259: if (allow_bare_port && strchr(opt, ':') == NULL) {
260: /*
261: * Allow a bare port number in permitlisten to indicate a
262: * listen_host wildcard.
263: */
1.85 deraadt 264: if (asprintf(&tmp, "*:%s", opt) == -1) {
1.83 djm 265: *errstrp = "memory allocation failed";
266: return -1;
267: }
268: free(opt);
269: opt = tmp;
270: }
1.80 djm 271: if ((tmp = strdup(opt)) == NULL) {
272: free(opt);
273: *errstrp = "memory allocation failed";
274: return -1;
275: }
276: cp = tmp;
277: /* validate syntax before recording it. */
278: host = hpdelim(&cp);
279: if (host == NULL || strlen(host) >= NI_MAXHOST) {
280: free(tmp);
281: free(opt);
282: *errstrp = "invalid permission hostname";
283: return -1;
284: }
285: /*
286: * don't want to use permitopen_port to avoid
287: * dependency on channels.[ch] here.
288: */
289: if (cp == NULL ||
290: (strcmp(cp, "*") != 0 && a2port(cp) <= 0)) {
291: free(tmp);
292: free(opt);
293: *errstrp = "invalid permission port";
294: return -1;
295: }
296: /* XXX - add streamlocal support */
297: free(tmp);
298: /* Record it */
299: if ((permits = recallocarray(permits, npermits, npermits + 1,
300: sizeof(*permits))) == NULL) {
301: free(opt);
302: /* NB. don't update *permitsp if alloc fails */
303: *errstrp = "memory allocation failed";
304: return -1;
305: }
306: permits[npermits++] = opt;
307: *permitsp = permits;
308: *npermitsp = npermits;
309: return 0;
310: }
311:
1.75 djm 312: struct sshauthopt *
313: sshauthopt_parse(const char *opts, const char **errstrp)
314: {
1.80 djm 315: char **oarray, *opt, *cp, *tmp;
1.75 djm 316: int r;
317: struct sshauthopt *ret = NULL;
318: const char *errstr = "unknown error";
1.77 djm 319: uint64_t valid_before;
1.75 djm 320:
321: if (errstrp != NULL)
322: *errstrp = NULL;
323: if ((ret = sshauthopt_new_with_keys_defaults()) == NULL)
324: goto alloc_fail;
325:
326: if (opts == NULL)
327: return ret;
328:
329: while (*opts && *opts != ' ' && *opts != '\t') {
330: /* flag options */
331: if ((r = opt_flag("restrict", 0, &opts)) != -1) {
332: ret->restricted = 1;
333: ret->permit_port_forwarding_flag = 0;
334: ret->permit_agent_forwarding_flag = 0;
335: ret->permit_x11_forwarding_flag = 0;
336: ret->permit_pty_flag = 0;
337: ret->permit_user_rc = 0;
338: } else if ((r = opt_flag("cert-authority", 0, &opts)) != -1) {
339: ret->cert_authority = r;
340: } else if ((r = opt_flag("port-forwarding", 1, &opts)) != -1) {
341: ret->permit_port_forwarding_flag = r == 1;
342: } else if ((r = opt_flag("agent-forwarding", 1, &opts)) != -1) {
343: ret->permit_agent_forwarding_flag = r == 1;
344: } else if ((r = opt_flag("x11-forwarding", 1, &opts)) != -1) {
345: ret->permit_x11_forwarding_flag = r == 1;
346: } else if ((r = opt_flag("pty", 1, &opts)) != -1) {
347: ret->permit_pty_flag = r == 1;
348: } else if ((r = opt_flag("user-rc", 1, &opts)) != -1) {
349: ret->permit_user_rc = r == 1;
350: } else if (opt_match(&opts, "command")) {
351: if (ret->force_command != NULL) {
352: errstr = "multiple \"command\" clauses";
353: goto fail;
354: }
355: ret->force_command = opt_dequote(&opts, &errstr);
356: if (ret->force_command == NULL)
357: goto fail;
358: } else if (opt_match(&opts, "principals")) {
359: if (ret->cert_principals != NULL) {
360: errstr = "multiple \"principals\" clauses";
361: goto fail;
362: }
363: ret->cert_principals = opt_dequote(&opts, &errstr);
364: if (ret->cert_principals == NULL)
365: goto fail;
366: } else if (opt_match(&opts, "from")) {
367: if (ret->required_from_host_keys != NULL) {
368: errstr = "multiple \"from\" clauses";
369: goto fail;
370: }
371: ret->required_from_host_keys = opt_dequote(&opts,
372: &errstr);
373: if (ret->required_from_host_keys == NULL)
374: goto fail;
1.78 djm 375: } else if (opt_match(&opts, "expiry-time")) {
1.77 djm 376: if ((opt = opt_dequote(&opts, &errstr)) == NULL)
377: goto fail;
378: if (parse_absolute_time(opt, &valid_before) != 0 ||
379: valid_before == 0) {
380: free(opt);
381: errstr = "invalid expires time";
382: goto fail;
383: }
384: free(opt);
385: if (ret->valid_before == 0 ||
386: valid_before < ret->valid_before)
387: ret->valid_before = valid_before;
1.75 djm 388: } else if (opt_match(&opts, "environment")) {
389: if (ret->nenv > INT_MAX) {
390: errstr = "too many environment strings";
391: goto fail;
392: }
393: if ((opt = opt_dequote(&opts, &errstr)) == NULL)
394: goto fail;
395: /* env name must be alphanumeric and followed by '=' */
396: if ((tmp = strchr(opt, '=')) == NULL) {
397: free(opt);
398: errstr = "invalid environment string";
399: goto fail;
400: }
1.84 djm 401: if ((cp = strdup(opt)) == NULL)
402: goto alloc_fail;
403: cp[tmp - opt] = '\0'; /* truncate at '=' */
404: if (!valid_env_name(cp)) {
405: free(cp);
406: free(opt);
407: errstr = "invalid environment string";
408: goto fail;
1.75 djm 409: }
1.84 djm 410: free(cp);
1.75 djm 411: /* Append it. */
412: oarray = ret->env;
413: if ((ret->env = recallocarray(ret->env, ret->nenv,
414: ret->nenv + 1, sizeof(*ret->env))) == NULL) {
415: free(opt);
416: ret->env = oarray; /* put it back for cleanup */
417: goto alloc_fail;
418: }
419: ret->env[ret->nenv++] = opt;
420: } else if (opt_match(&opts, "permitopen")) {
1.83 djm 421: if (handle_permit(&opts, 0, &ret->permitopen,
1.80 djm 422: &ret->npermitopen, &errstr) != 0)
1.75 djm 423: goto fail;
1.80 djm 424: } else if (opt_match(&opts, "permitlisten")) {
1.83 djm 425: if (handle_permit(&opts, 1, &ret->permitlisten,
1.80 djm 426: &ret->npermitlisten, &errstr) != 0)
1.75 djm 427: goto fail;
428: } else if (opt_match(&opts, "tunnel")) {
429: if ((opt = opt_dequote(&opts, &errstr)) == NULL)
430: goto fail;
431: ret->force_tun_device = a2tun(opt, NULL);
432: free(opt);
433: if (ret->force_tun_device == SSH_TUNID_ERR) {
434: errstr = "invalid tun device";
435: goto fail;
436: }
437: }
438: /*
439: * Skip the comma, and move to the next option
440: * (or break out if there are no more).
441: */
442: if (*opts == '\0' || *opts == ' ' || *opts == '\t')
443: break; /* End of options. */
444: /* Anything other than a comma is an unknown option */
445: if (*opts != ',') {
446: errstr = "unknown key option";
447: goto fail;
448: }
449: opts++;
450: if (*opts == '\0') {
451: errstr = "unexpected end-of-options";
452: goto fail;
453: }
454: }
455:
456: /* success */
457: if (errstrp != NULL)
458: *errstrp = NULL;
459: return ret;
460:
461: alloc_fail:
462: errstr = "memory allocation failed";
463: fail:
464: sshauthopt_free(ret);
465: if (errstrp != NULL)
466: *errstrp = errstr;
467: return NULL;
468: }
469:
470: struct sshauthopt *
471: sshauthopt_from_cert(struct sshkey *k)
472: {
473: struct sshauthopt *ret;
474:
475: if (k == NULL || !sshkey_type_is_cert(k->type) || k->cert == NULL ||
476: k->cert->type != SSH2_CERT_TYPE_USER)
477: return NULL;
478:
479: if ((ret = sshauthopt_new()) == NULL)
480: return NULL;
481:
482: /* Handle options and critical extensions separately */
483: if (cert_option_list(ret, k->cert->critical,
484: OPTIONS_CRITICAL, 1) == -1) {
485: sshauthopt_free(ret);
486: return NULL;
487: }
488: if (cert_option_list(ret, k->cert->extensions,
489: OPTIONS_EXTENSIONS, 0) == -1) {
490: sshauthopt_free(ret);
491: return NULL;
492: }
493: /* success */
494: return ret;
495: }
496:
497: /*
498: * Merges "additional" options to "primary" and returns the result.
499: * NB. Some options from primary have primacy.
500: */
501: struct sshauthopt *
502: sshauthopt_merge(const struct sshauthopt *primary,
503: const struct sshauthopt *additional, const char **errstrp)
504: {
505: struct sshauthopt *ret;
506: const char *errstr = "internal error";
507: const char *tmp;
508:
509: if (errstrp != NULL)
510: *errstrp = NULL;
511:
512: if ((ret = sshauthopt_new()) == NULL)
513: goto alloc_fail;
514:
515: /* cert_authority and cert_principals are cleared in result */
516:
517: /* Prefer access lists from primary. */
518: /* XXX err is both set and mismatch? */
519: tmp = primary->required_from_host_cert;
520: if (tmp == NULL)
521: tmp = additional->required_from_host_cert;
522: if (tmp != NULL && (ret->required_from_host_cert = strdup(tmp)) == NULL)
523: goto alloc_fail;
524: tmp = primary->required_from_host_keys;
525: if (tmp == NULL)
526: tmp = additional->required_from_host_keys;
527: if (tmp != NULL && (ret->required_from_host_keys = strdup(tmp)) == NULL)
528: goto alloc_fail;
529:
1.80 djm 530: /*
531: * force_tun_device, permitopen/permitlisten and environment all
532: * prefer the primary.
533: */
1.75 djm 534: ret->force_tun_device = primary->force_tun_device;
535: if (ret->force_tun_device == -1)
536: ret->force_tun_device = additional->force_tun_device;
537: if (primary->nenv > 0) {
538: if (dup_strings(&ret->env, &ret->nenv,
539: primary->env, primary->nenv) != 0)
540: goto alloc_fail;
541: } else if (additional->nenv) {
542: if (dup_strings(&ret->env, &ret->nenv,
543: additional->env, additional->nenv) != 0)
544: goto alloc_fail;
545: }
546: if (primary->npermitopen > 0) {
547: if (dup_strings(&ret->permitopen, &ret->npermitopen,
548: primary->permitopen, primary->npermitopen) != 0)
549: goto alloc_fail;
550: } else if (additional->npermitopen > 0) {
551: if (dup_strings(&ret->permitopen, &ret->npermitopen,
552: additional->permitopen, additional->npermitopen) != 0)
553: goto alloc_fail;
554: }
555:
1.80 djm 556: if (primary->npermitlisten > 0) {
557: if (dup_strings(&ret->permitlisten, &ret->npermitlisten,
558: primary->permitlisten, primary->npermitlisten) != 0)
559: goto alloc_fail;
560: } else if (additional->npermitlisten > 0) {
561: if (dup_strings(&ret->permitlisten, &ret->npermitlisten,
562: additional->permitlisten, additional->npermitlisten) != 0)
563: goto alloc_fail;
564: }
565:
1.75 djm 566: /* Flags are logical-AND (i.e. must be set in both for permission) */
567: #define OPTFLAG(x) ret->x = (primary->x == 1) && (additional->x == 1)
568: OPTFLAG(permit_port_forwarding_flag);
569: OPTFLAG(permit_agent_forwarding_flag);
570: OPTFLAG(permit_x11_forwarding_flag);
571: OPTFLAG(permit_pty_flag);
572: OPTFLAG(permit_user_rc);
573: #undef OPTFLAG
574:
1.77 djm 575: /* Earliest expiry time should win */
576: if (primary->valid_before != 0)
577: ret->valid_before = primary->valid_before;
578: if (additional->valid_before != 0 &&
579: additional->valid_before < ret->valid_before)
580: ret->valid_before = additional->valid_before;
581:
1.75 djm 582: /*
583: * When both multiple forced-command are specified, only
584: * proceed if they are identical, otherwise fail.
585: */
586: if (primary->force_command != NULL &&
587: additional->force_command != NULL) {
588: if (strcmp(primary->force_command,
589: additional->force_command) == 0) {
590: /* ok */
591: ret->force_command = strdup(primary->force_command);
592: if (ret->force_command == NULL)
593: goto alloc_fail;
594: } else {
595: errstr = "forced command options do not match";
596: goto fail;
597: }
598: } else if (primary->force_command != NULL) {
599: if ((ret->force_command = strdup(
600: primary->force_command)) == NULL)
601: goto alloc_fail;
602: } else if (additional->force_command != NULL) {
603: if ((ret->force_command = strdup(
604: additional->force_command)) == NULL)
605: goto alloc_fail;
606: }
607: /* success */
608: if (errstrp != NULL)
609: *errstrp = NULL;
610: return ret;
611:
612: alloc_fail:
613: errstr = "memory allocation failed";
614: fail:
615: if (errstrp != NULL)
616: *errstrp = errstr;
617: sshauthopt_free(ret);
618: return NULL;
619: }
620:
621: /*
622: * Copy options
623: */
624: struct sshauthopt *
625: sshauthopt_copy(const struct sshauthopt *orig)
626: {
627: struct sshauthopt *ret;
628:
629: if ((ret = sshauthopt_new()) == NULL)
630: return NULL;
631:
632: #define OPTSCALAR(x) ret->x = orig->x
633: OPTSCALAR(permit_port_forwarding_flag);
634: OPTSCALAR(permit_agent_forwarding_flag);
635: OPTSCALAR(permit_x11_forwarding_flag);
636: OPTSCALAR(permit_pty_flag);
637: OPTSCALAR(permit_user_rc);
638: OPTSCALAR(restricted);
639: OPTSCALAR(cert_authority);
640: OPTSCALAR(force_tun_device);
1.77 djm 641: OPTSCALAR(valid_before);
1.75 djm 642: #undef OPTSCALAR
643: #define OPTSTRING(x) \
644: do { \
645: if (orig->x != NULL && (ret->x = strdup(orig->x)) == NULL) { \
646: sshauthopt_free(ret); \
647: return NULL; \
648: } \
649: } while (0)
650: OPTSTRING(cert_principals);
651: OPTSTRING(force_command);
652: OPTSTRING(required_from_host_cert);
653: OPTSTRING(required_from_host_keys);
654: #undef OPTSTRING
655:
656: if (dup_strings(&ret->env, &ret->nenv, orig->env, orig->nenv) != 0 ||
657: dup_strings(&ret->permitopen, &ret->npermitopen,
1.80 djm 658: orig->permitopen, orig->npermitopen) != 0 ||
659: dup_strings(&ret->permitlisten, &ret->npermitlisten,
660: orig->permitlisten, orig->npermitlisten) != 0) {
1.75 djm 661: sshauthopt_free(ret);
662: return NULL;
663: }
664: return ret;
665: }
666:
667: static int
668: serialise_array(struct sshbuf *m, char **a, size_t n)
669: {
670: struct sshbuf *b;
671: size_t i;
672: int r;
673:
674: if (n > INT_MAX)
675: return SSH_ERR_INTERNAL_ERROR;
676:
677: if ((b = sshbuf_new()) == NULL) {
678: return SSH_ERR_ALLOC_FAIL;
679: }
680: for (i = 0; i < n; i++) {
681: if ((r = sshbuf_put_cstring(b, a[i])) != 0) {
682: sshbuf_free(b);
683: return r;
684: }
685: }
686: if ((r = sshbuf_put_u32(m, n)) != 0 ||
687: (r = sshbuf_put_stringb(m, b)) != 0) {
688: sshbuf_free(b);
689: return r;
690: }
691: /* success */
692: return 0;
693: }
694:
695: static int
696: deserialise_array(struct sshbuf *m, char ***ap, size_t *np)
697: {
698: char **a = NULL;
699: size_t i, n = 0;
700: struct sshbuf *b = NULL;
701: u_int tmp;
702: int r = SSH_ERR_INTERNAL_ERROR;
703:
704: if ((r = sshbuf_get_u32(m, &tmp)) != 0 ||
705: (r = sshbuf_froms(m, &b)) != 0)
706: goto out;
707: if (tmp > INT_MAX) {
708: r = SSH_ERR_INVALID_FORMAT;
709: goto out;
710: }
711: n = tmp;
712: if (n > 0 && (a = calloc(n, sizeof(*a))) == NULL) {
713: r = SSH_ERR_ALLOC_FAIL;
714: goto out;
715: }
716: for (i = 0; i < n; i++) {
717: if ((r = sshbuf_get_cstring(b, &a[i], NULL)) != 0)
718: goto out;
719: }
720: /* success */
721: r = 0;
722: *ap = a;
723: a = NULL;
724: *np = n;
725: n = 0;
726: out:
727: for (i = 0; i < n; i++)
728: free(a[i]);
729: free(a);
730: sshbuf_free(b);
731: return r;
732: }
733:
734: static int
735: serialise_nullable_string(struct sshbuf *m, const char *s)
736: {
737: int r;
738:
739: if ((r = sshbuf_put_u8(m, s == NULL)) != 0 ||
740: (r = sshbuf_put_cstring(m, s)) != 0)
741: return r;
742: return 0;
743: }
744:
745: static int
746: deserialise_nullable_string(struct sshbuf *m, char **sp)
747: {
748: int r;
749: u_char flag;
750:
751: *sp = NULL;
752: if ((r = sshbuf_get_u8(m, &flag)) != 0 ||
753: (r = sshbuf_get_cstring(m, flag ? NULL : sp, NULL)) != 0)
754: return r;
755: return 0;
756: }
757:
758: int
759: sshauthopt_serialise(const struct sshauthopt *opts, struct sshbuf *m,
760: int untrusted)
761: {
762: int r = SSH_ERR_INTERNAL_ERROR;
763:
1.77 djm 764: /* Flag and simple integer options */
1.75 djm 765: if ((r = sshbuf_put_u8(m, opts->permit_port_forwarding_flag)) != 0 ||
766: (r = sshbuf_put_u8(m, opts->permit_agent_forwarding_flag)) != 0 ||
767: (r = sshbuf_put_u8(m, opts->permit_x11_forwarding_flag)) != 0 ||
768: (r = sshbuf_put_u8(m, opts->permit_pty_flag)) != 0 ||
769: (r = sshbuf_put_u8(m, opts->permit_user_rc)) != 0 ||
770: (r = sshbuf_put_u8(m, opts->restricted)) != 0 ||
1.77 djm 771: (r = sshbuf_put_u8(m, opts->cert_authority)) != 0 ||
772: (r = sshbuf_put_u64(m, opts->valid_before)) != 0)
1.75 djm 773: return r;
774:
775: /* tunnel number can be negative to indicate "unset" */
776: if ((r = sshbuf_put_u8(m, opts->force_tun_device == -1)) != 0 ||
777: (r = sshbuf_put_u32(m, (opts->force_tun_device < 0) ?
778: 0 : (u_int)opts->force_tun_device)) != 0)
779: return r;
780:
781: /* String options; these may be NULL */
782: if ((r = serialise_nullable_string(m,
783: untrusted ? "yes" : opts->cert_principals)) != 0 ||
784: (r = serialise_nullable_string(m,
785: untrusted ? "true" : opts->force_command)) != 0 ||
786: (r = serialise_nullable_string(m,
787: untrusted ? NULL : opts->required_from_host_cert)) != 0 ||
788: (r = serialise_nullable_string(m,
789: untrusted ? NULL : opts->required_from_host_keys)) != 0)
790: return r;
791:
792: /* Array options */
793: if ((r = serialise_array(m, opts->env,
794: untrusted ? 0 : opts->nenv)) != 0 ||
795: (r = serialise_array(m, opts->permitopen,
1.82 djm 796: untrusted ? 0 : opts->npermitopen)) != 0 ||
1.80 djm 797: (r = serialise_array(m, opts->permitlisten,
798: untrusted ? 0 : opts->npermitlisten)) != 0)
1.75 djm 799: return r;
800:
801: /* success */
802: return 0;
803: }
804:
805: int
806: sshauthopt_deserialise(struct sshbuf *m, struct sshauthopt **optsp)
807: {
808: struct sshauthopt *opts = NULL;
809: int r = SSH_ERR_INTERNAL_ERROR;
810: u_char f;
811: u_int tmp;
812:
813: if ((opts = calloc(1, sizeof(*opts))) == NULL)
814: return SSH_ERR_ALLOC_FAIL;
815:
816: #define OPT_FLAG(x) \
817: do { \
818: if ((r = sshbuf_get_u8(m, &f)) != 0) \
819: goto out; \
820: opts->x = f; \
821: } while (0)
822: OPT_FLAG(permit_port_forwarding_flag);
823: OPT_FLAG(permit_agent_forwarding_flag);
824: OPT_FLAG(permit_x11_forwarding_flag);
825: OPT_FLAG(permit_pty_flag);
826: OPT_FLAG(permit_user_rc);
827: OPT_FLAG(restricted);
828: OPT_FLAG(cert_authority);
829: #undef OPT_FLAG
1.77 djm 830:
831: if ((r = sshbuf_get_u64(m, &opts->valid_before)) != 0)
832: goto out;
1.75 djm 833:
834: /* tunnel number can be negative to indicate "unset" */
835: if ((r = sshbuf_get_u8(m, &f)) != 0 ||
836: (r = sshbuf_get_u32(m, &tmp)) != 0)
837: goto out;
838: opts->force_tun_device = f ? -1 : (int)tmp;
839:
840: /* String options may be NULL */
841: if ((r = deserialise_nullable_string(m, &opts->cert_principals)) != 0 ||
842: (r = deserialise_nullable_string(m, &opts->force_command)) != 0 ||
843: (r = deserialise_nullable_string(m,
844: &opts->required_from_host_cert)) != 0 ||
845: (r = deserialise_nullable_string(m,
846: &opts->required_from_host_keys)) != 0)
847: goto out;
848:
849: /* Array options */
850: if ((r = deserialise_array(m, &opts->env, &opts->nenv)) != 0 ||
851: (r = deserialise_array(m,
1.80 djm 852: &opts->permitopen, &opts->npermitopen)) != 0 ||
853: (r = deserialise_array(m,
854: &opts->permitlisten, &opts->npermitlisten)) != 0)
1.75 djm 855: goto out;
856:
857: /* success */
858: r = 0;
859: *optsp = opts;
860: opts = NULL;
861: out:
862: sshauthopt_free(opts);
863: return r;
864: }