1 /* $OpenBSD: x509_ncons.c,v 1.4 2020/09/16 18:12:06 beck Exp $ */
2 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
3 * project.
4 */
5 /* ====================================================================
6 * Copyright (c) 2003 The OpenSSL Project. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
18 * distribution.
19 *
20 * 3. All advertising materials mentioning features or use of this
21 * software must display the following acknowledgment:
22 * "This product includes software developed by the OpenSSL Project
23 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
24 *
25 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26 * endorse or promote products derived from this software without
27 * prior written permission. For written permission, please contact
28 * licensing@OpenSSL.org.
29 *
30 * 5. Products derived from this software may not be called "OpenSSL"
31 * nor may "OpenSSL" appear in their names without prior written
32 * permission of the OpenSSL Project.
33 *
34 * 6. Redistributions of any form whatsoever must retain the following
35 * acknowledgment:
36 * "This product includes software developed by the OpenSSL Project
37 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
38 *
39 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
40 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
43 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
45 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50 * OF THE POSSIBILITY OF SUCH DAMAGE.
51 * ====================================================================
52 *
53 * This product includes cryptographic software written by Eric Young
54 * (eay@cryptsoft.com). This product includes software written by Tim
55 * Hudson (tjh@cryptsoft.com).
56 *
57 */
58
59 #include <stdio.h>
60 #include <string.h>
61
62 #include <openssl/asn1t.h>
63 #include <openssl/conf.h>
64 #include <openssl/err.h>
65 #include <openssl/x509v3.h>
66
67 static void *v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method,
68 X509V3_CTX *ctx, STACK_OF(CONF_VALUE) *nval);
69 static int i2r_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method,
70 void *a, BIO *bp, int ind);
71 static int do_i2r_name_constraints(const X509V3_EXT_METHOD *method,
72 STACK_OF(GENERAL_SUBTREE) *trees, BIO *bp, int ind, char *name);
73 static int print_nc_ipadd(BIO *bp, ASN1_OCTET_STRING *ip);
74
75 static int nc_match(GENERAL_NAME *gen, NAME_CONSTRAINTS *nc);
76 static int nc_match_single(GENERAL_NAME *sub, GENERAL_NAME *gen);
77 static int nc_dn(X509_NAME *sub, X509_NAME *nm);
78 static int nc_dns(ASN1_IA5STRING *sub, ASN1_IA5STRING *dns);
79 static int nc_email(ASN1_IA5STRING *sub, ASN1_IA5STRING *eml);
80 static int nc_uri(ASN1_IA5STRING *uri, ASN1_IA5STRING *base);
81
82 const X509V3_EXT_METHOD v3_name_constraints = {
83 .ext_nid = NID_name_constraints,
84 .ext_flags = 0,
85 .it = &NAME_CONSTRAINTS_it,
86 .ext_new = NULL,
87 .ext_free = NULL,
88 .d2i = NULL,
89 .i2d = NULL,
90 .i2s = NULL,
91 .s2i = NULL,
92 .i2v = NULL,
93 .v2i = v2i_NAME_CONSTRAINTS,
94 .i2r = i2r_NAME_CONSTRAINTS,
95 .r2i = NULL,
96 .usr_data = NULL,
97 };
98
99 static const ASN1_TEMPLATE GENERAL_SUBTREE_seq_tt[] = {
100 {
101 .flags = 0,
102 .tag = 0,
103 .offset = offsetof(GENERAL_SUBTREE, base),
104 .field_name = "base",
105 .item = &GENERAL_NAME_it,
106 },
107 {
108 .flags = ASN1_TFLG_IMPLICIT | ASN1_TFLG_OPTIONAL,
109 .tag = 0,
110 .offset = offsetof(GENERAL_SUBTREE, minimum),
111 .field_name = "minimum",
112 .item = &ASN1_INTEGER_it,
113 },
114 {
115 .flags = ASN1_TFLG_IMPLICIT | ASN1_TFLG_OPTIONAL,
116 .tag = 1,
117 .offset = offsetof(GENERAL_SUBTREE, maximum),
118 .field_name = "maximum",
119 .item = &ASN1_INTEGER_it,
120 },
121 };
122
123 const ASN1_ITEM GENERAL_SUBTREE_it = {
124 .itype = ASN1_ITYPE_SEQUENCE,
125 .utype = V_ASN1_SEQUENCE,
126 .templates = GENERAL_SUBTREE_seq_tt,
127 .tcount = sizeof(GENERAL_SUBTREE_seq_tt) / sizeof(ASN1_TEMPLATE),
128 .funcs = NULL,
129 .size = sizeof(GENERAL_SUBTREE),
130 .sname = "GENERAL_SUBTREE",
131 };
132
133 static const ASN1_TEMPLATE NAME_CONSTRAINTS_seq_tt[] = {
134 {
135 .flags = ASN1_TFLG_IMPLICIT | ASN1_TFLG_SEQUENCE_OF | ASN1_TFLG_OPTIONAL,
136 .tag = 0,
137 .offset = offsetof(NAME_CONSTRAINTS, permittedSubtrees),
138 .field_name = "permittedSubtrees",
139 .item = &GENERAL_SUBTREE_it,
140 },
141 {
142 .flags = ASN1_TFLG_IMPLICIT | ASN1_TFLG_SEQUENCE_OF | ASN1_TFLG_OPTIONAL,
143 .tag = 1,
144 .offset = offsetof(NAME_CONSTRAINTS, excludedSubtrees),
145 .field_name = "excludedSubtrees",
146 .item = &GENERAL_SUBTREE_it,
147 },
148 };
149
150 const ASN1_ITEM NAME_CONSTRAINTS_it = {
151 .itype = ASN1_ITYPE_SEQUENCE,
152 .utype = V_ASN1_SEQUENCE,
153 .templates = NAME_CONSTRAINTS_seq_tt,
154 .tcount = sizeof(NAME_CONSTRAINTS_seq_tt) / sizeof(ASN1_TEMPLATE),
155 .funcs = NULL,
156 .size = sizeof(NAME_CONSTRAINTS),
157 .sname = "NAME_CONSTRAINTS",
158 };
159
160
161 GENERAL_SUBTREE *
GENERAL_SUBTREE_new(void)162 GENERAL_SUBTREE_new(void)
163 {
164 return (GENERAL_SUBTREE*)ASN1_item_new(&GENERAL_SUBTREE_it);
165 }
166
167 void
GENERAL_SUBTREE_free(GENERAL_SUBTREE * a)168 GENERAL_SUBTREE_free(GENERAL_SUBTREE *a)
169 {
170 ASN1_item_free((ASN1_VALUE *)a, &GENERAL_SUBTREE_it);
171 }
172
173 NAME_CONSTRAINTS *
NAME_CONSTRAINTS_new(void)174 NAME_CONSTRAINTS_new(void)
175 {
176 return (NAME_CONSTRAINTS*)ASN1_item_new(&NAME_CONSTRAINTS_it);
177 }
178
179 void
NAME_CONSTRAINTS_free(NAME_CONSTRAINTS * a)180 NAME_CONSTRAINTS_free(NAME_CONSTRAINTS *a)
181 {
182 ASN1_item_free((ASN1_VALUE *)a, &NAME_CONSTRAINTS_it);
183 }
184
185 static void *
v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD * method,X509V3_CTX * ctx,STACK_OF (CONF_VALUE)* nval)186 v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, X509V3_CTX *ctx,
187 STACK_OF(CONF_VALUE) *nval)
188 {
189 int i;
190 CONF_VALUE tval, *val;
191 STACK_OF(GENERAL_SUBTREE) **ptree = NULL;
192 NAME_CONSTRAINTS *ncons = NULL;
193 GENERAL_SUBTREE *sub = NULL;
194
195 ncons = NAME_CONSTRAINTS_new();
196 if (!ncons)
197 goto memerr;
198 for (i = 0; i < sk_CONF_VALUE_num(nval); i++) {
199 val = sk_CONF_VALUE_value(nval, i);
200 if (!strncmp(val->name, "permitted", 9) && val->name[9]) {
201 ptree = &ncons->permittedSubtrees;
202 tval.name = val->name + 10;
203 } else if (!strncmp(val->name, "excluded", 8) && val->name[8]) {
204 ptree = &ncons->excludedSubtrees;
205 tval.name = val->name + 9;
206 } else {
207 X509V3error(X509V3_R_INVALID_SYNTAX);
208 goto err;
209 }
210 tval.value = val->value;
211 sub = GENERAL_SUBTREE_new();
212 if (!v2i_GENERAL_NAME_ex(sub->base, method, ctx, &tval, 1))
213 goto err;
214 if (!*ptree)
215 *ptree = sk_GENERAL_SUBTREE_new_null();
216 if (!*ptree || !sk_GENERAL_SUBTREE_push(*ptree, sub))
217 goto memerr;
218 sub = NULL;
219 }
220
221 return ncons;
222
223 memerr:
224 X509V3error(ERR_R_MALLOC_FAILURE);
225 err:
226 NAME_CONSTRAINTS_free(ncons);
227 GENERAL_SUBTREE_free(sub);
228 return NULL;
229 }
230
231 static int
i2r_NAME_CONSTRAINTS(const X509V3_EXT_METHOD * method,void * a,BIO * bp,int ind)232 i2r_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, void *a, BIO *bp, int ind)
233 {
234 NAME_CONSTRAINTS *ncons = a;
235
236 do_i2r_name_constraints(method, ncons->permittedSubtrees,
237 bp, ind, "Permitted");
238 do_i2r_name_constraints(method, ncons->excludedSubtrees,
239 bp, ind, "Excluded");
240 return 1;
241 }
242
243 static int
do_i2r_name_constraints(const X509V3_EXT_METHOD * method,STACK_OF (GENERAL_SUBTREE)* trees,BIO * bp,int ind,char * name)244 do_i2r_name_constraints(const X509V3_EXT_METHOD *method,
245 STACK_OF(GENERAL_SUBTREE) *trees, BIO *bp, int ind, char *name)
246 {
247 GENERAL_SUBTREE *tree;
248 int i;
249
250 if (sk_GENERAL_SUBTREE_num(trees) > 0)
251 BIO_printf(bp, "%*s%s:\n", ind, "", name);
252 for (i = 0; i < sk_GENERAL_SUBTREE_num(trees); i++) {
253 tree = sk_GENERAL_SUBTREE_value(trees, i);
254 BIO_printf(bp, "%*s", ind + 2, "");
255 if (tree->base->type == GEN_IPADD)
256 print_nc_ipadd(bp, tree->base->d.ip);
257 else
258 GENERAL_NAME_print(bp, tree->base);
259 BIO_puts(bp, "\n");
260 }
261 return 1;
262 }
263
264 static int
print_nc_ipadd(BIO * bp,ASN1_OCTET_STRING * ip)265 print_nc_ipadd(BIO *bp, ASN1_OCTET_STRING *ip)
266 {
267 int i, len;
268 unsigned char *p;
269
270 p = ip->data;
271 len = ip->length;
272 BIO_puts(bp, "IP:");
273 if (len == 8) {
274 BIO_printf(bp, "%d.%d.%d.%d/%d.%d.%d.%d",
275 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]);
276 } else if (len == 32) {
277 for (i = 0; i < 16; i++) {
278 BIO_printf(bp, "%X", p[0] << 8 | p[1]);
279 p += 2;
280 if (i == 7)
281 BIO_puts(bp, "/");
282 else if (i != 15)
283 BIO_puts(bp, ":");
284 }
285 } else
286 BIO_printf(bp, "IP Address:<invalid>");
287 return 1;
288 }
289
290 /* Check a certificate conforms to a specified set of constraints.
291 * Return values:
292 * X509_V_OK: All constraints obeyed.
293 * X509_V_ERR_PERMITTED_VIOLATION: Permitted subtree violation.
294 * X509_V_ERR_EXCLUDED_VIOLATION: Excluded subtree violation.
295 * X509_V_ERR_SUBTREE_MINMAX: Min or max values present and matching type.
296 * X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE: Unsupported constraint type.
297 * X509_V_ERR_UNSUPPORTED_CONSTRAINT_SYNTAX: bad unsupported constraint syntax.
298 * X509_V_ERR_UNSUPPORTED_NAME_SYNTAX: bad or unsupported syntax of name
299 */
300
301 int
NAME_CONSTRAINTS_check(X509 * x,NAME_CONSTRAINTS * nc)302 NAME_CONSTRAINTS_check(X509 *x, NAME_CONSTRAINTS *nc)
303 {
304 int r, i;
305 X509_NAME *nm;
306
307 nm = X509_get_subject_name(x);
308
309 if (X509_NAME_entry_count(nm) > 0) {
310 GENERAL_NAME gntmp;
311 gntmp.type = GEN_DIRNAME;
312 gntmp.d.directoryName = nm;
313
314 r = nc_match(&gntmp, nc);
315
316 if (r != X509_V_OK)
317 return r;
318
319 gntmp.type = GEN_EMAIL;
320
321 /* Process any email address attributes in subject name */
322
323 for (i = -1;;) {
324 X509_NAME_ENTRY *ne;
325 i = X509_NAME_get_index_by_NID(nm,
326 NID_pkcs9_emailAddress, i);
327 if (i == -1)
328 break;
329 ne = X509_NAME_get_entry(nm, i);
330 gntmp.d.rfc822Name = X509_NAME_ENTRY_get_data(ne);
331 if (gntmp.d.rfc822Name->type != V_ASN1_IA5STRING)
332 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
333
334 r = nc_match(&gntmp, nc);
335
336 if (r != X509_V_OK)
337 return r;
338 }
339
340 }
341
342 for (i = 0; i < sk_GENERAL_NAME_num(x->altname); i++) {
343 GENERAL_NAME *gen = sk_GENERAL_NAME_value(x->altname, i);
344 r = nc_match(gen, nc);
345 if (r != X509_V_OK)
346 return r;
347 }
348 return X509_V_OK;
349 }
350 static int
nc_match(GENERAL_NAME * gen,NAME_CONSTRAINTS * nc)351 nc_match(GENERAL_NAME *gen, NAME_CONSTRAINTS *nc)
352 {
353 GENERAL_SUBTREE *sub;
354 int i, r, match = 0;
355
356 /* Permitted subtrees: if any subtrees exist of matching the type
357 * at least one subtree must match.
358 */
359
360 for (i = 0; i < sk_GENERAL_SUBTREE_num(nc->permittedSubtrees); i++) {
361 sub = sk_GENERAL_SUBTREE_value(nc->permittedSubtrees, i);
362 if (gen->type != sub->base->type)
363 continue;
364 if (sub->minimum || sub->maximum)
365 return X509_V_ERR_SUBTREE_MINMAX;
366 /* If we already have a match don't bother trying any more */
367 if (match == 2)
368 continue;
369 if (match == 0)
370 match = 1;
371 r = nc_match_single(gen, sub->base);
372 if (r == X509_V_OK)
373 match = 2;
374 else if (r != X509_V_ERR_PERMITTED_VIOLATION)
375 return r;
376 }
377
378 if (match == 1)
379 return X509_V_ERR_PERMITTED_VIOLATION;
380
381 /* Excluded subtrees: must not match any of these */
382
383 for (i = 0; i < sk_GENERAL_SUBTREE_num(nc->excludedSubtrees); i++) {
384 sub = sk_GENERAL_SUBTREE_value(nc->excludedSubtrees, i);
385 if (gen->type != sub->base->type)
386 continue;
387 if (sub->minimum || sub->maximum)
388 return X509_V_ERR_SUBTREE_MINMAX;
389
390 r = nc_match_single(gen, sub->base);
391 if (r == X509_V_OK)
392 return X509_V_ERR_EXCLUDED_VIOLATION;
393 else if (r != X509_V_ERR_PERMITTED_VIOLATION)
394 return r;
395
396 }
397
398 return X509_V_OK;
399 }
400
401 static int
nc_match_single(GENERAL_NAME * gen,GENERAL_NAME * base)402 nc_match_single(GENERAL_NAME *gen, GENERAL_NAME *base)
403 {
404 switch (base->type) {
405 case GEN_DIRNAME:
406 return nc_dn(gen->d.directoryName, base->d.directoryName);
407
408 case GEN_DNS:
409 return nc_dns(gen->d.dNSName, base->d.dNSName);
410
411 case GEN_EMAIL:
412 return nc_email(gen->d.rfc822Name, base->d.rfc822Name);
413
414 case GEN_URI:
415 return nc_uri(gen->d.uniformResourceIdentifier,
416 base->d.uniformResourceIdentifier);
417
418 default:
419 return X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE;
420 }
421 }
422
423 /* directoryName name constraint matching.
424 * The canonical encoding of X509_NAME makes this comparison easy. It is
425 * matched if the subtree is a subset of the name.
426 */
427
428 static int
nc_dn(X509_NAME * nm,X509_NAME * base)429 nc_dn(X509_NAME *nm, X509_NAME *base)
430 {
431 /* Ensure canonical encodings are up to date. */
432 if (nm->modified && i2d_X509_NAME(nm, NULL) < 0)
433 return X509_V_ERR_OUT_OF_MEM;
434 if (base->modified && i2d_X509_NAME(base, NULL) < 0)
435 return X509_V_ERR_OUT_OF_MEM;
436 if (base->canon_enclen > nm->canon_enclen)
437 return X509_V_ERR_PERMITTED_VIOLATION;
438 if (memcmp(base->canon_enc, nm->canon_enc, base->canon_enclen))
439 return X509_V_ERR_PERMITTED_VIOLATION;
440 return X509_V_OK;
441 }
442
443 static int
nc_dns(ASN1_IA5STRING * dns,ASN1_IA5STRING * base)444 nc_dns(ASN1_IA5STRING *dns, ASN1_IA5STRING *base)
445 {
446 char *baseptr = (char *)base->data;
447 char *dnsptr = (char *)dns->data;
448
449 /* Empty matches everything */
450 if (!*baseptr)
451 return X509_V_OK;
452 /* Otherwise can add zero or more components on the left so
453 * compare RHS and if dns is longer and expect '.' as preceding
454 * character.
455 */
456 if (dns->length > base->length) {
457 dnsptr += dns->length - base->length;
458 if (baseptr[0] != '.' && dnsptr[-1] != '.')
459 return X509_V_ERR_PERMITTED_VIOLATION;
460 }
461
462 if (strcasecmp(baseptr, dnsptr))
463 return X509_V_ERR_PERMITTED_VIOLATION;
464
465 return X509_V_OK;
466 }
467
468 static int
nc_email(ASN1_IA5STRING * eml,ASN1_IA5STRING * base)469 nc_email(ASN1_IA5STRING *eml, ASN1_IA5STRING *base)
470 {
471 const char *baseptr = (char *)base->data;
472 const char *emlptr = (char *)eml->data;
473 const char *baseat = strchr(baseptr, '@');
474 const char *emlat = strchr(emlptr, '@');
475
476 if (!emlat)
477 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
478 /* Special case: inital '.' is RHS match */
479 if (!baseat && (*baseptr == '.')) {
480 if (eml->length > base->length) {
481 emlptr += eml->length - base->length;
482 if (!strcasecmp(baseptr, emlptr))
483 return X509_V_OK;
484 }
485 return X509_V_ERR_PERMITTED_VIOLATION;
486 }
487
488 /* If we have anything before '@' match local part */
489
490 if (baseat) {
491 if (baseat != baseptr) {
492 if ((baseat - baseptr) != (emlat - emlptr))
493 return X509_V_ERR_PERMITTED_VIOLATION;
494 /* Case sensitive match of local part */
495 if (strncmp(baseptr, emlptr, emlat - emlptr))
496 return X509_V_ERR_PERMITTED_VIOLATION;
497 }
498 /* Position base after '@' */
499 baseptr = baseat + 1;
500 }
501 emlptr = emlat + 1;
502 /* Just have hostname left to match: case insensitive */
503 if (strcasecmp(baseptr, emlptr))
504 return X509_V_ERR_PERMITTED_VIOLATION;
505
506 return X509_V_OK;
507 }
508
509 static int
nc_uri(ASN1_IA5STRING * uri,ASN1_IA5STRING * base)510 nc_uri(ASN1_IA5STRING *uri, ASN1_IA5STRING *base)
511 {
512 const char *baseptr = (char *)base->data;
513 const char *hostptr = (char *)uri->data;
514 const char *p = strchr(hostptr, ':');
515 int hostlen;
516
517 /* Check for foo:// and skip past it */
518 if (!p || (p[1] != '/') || (p[2] != '/'))
519 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
520 hostptr = p + 3;
521
522 /* Determine length of hostname part of URI */
523
524 /* Look for a port indicator as end of hostname first */
525
526 p = strchr(hostptr, ':');
527 /* Otherwise look for trailing slash */
528 if (!p)
529 p = strchr(hostptr, '/');
530
531 if (!p)
532 hostlen = strlen(hostptr);
533 else
534 hostlen = p - hostptr;
535
536 if (hostlen == 0)
537 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
538
539 /* Special case: inital '.' is RHS match */
540 if (*baseptr == '.') {
541 if (hostlen > base->length) {
542 p = hostptr + hostlen - base->length;
543 if (!strncasecmp(p, baseptr, base->length))
544 return X509_V_OK;
545 }
546 return X509_V_ERR_PERMITTED_VIOLATION;
547 }
548
549 if ((base->length != (int)hostlen) ||
550 strncasecmp(hostptr, baseptr, hostlen))
551 return X509_V_ERR_PERMITTED_VIOLATION;
552
553 return X509_V_OK;
554 }
555