1 /* $OpenBSD: x509_ncons.c,v 1.5 2021/11/01 20:53:08 tb 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 #include "x509_lcl.h"
68
69 static void *v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method,
70 X509V3_CTX *ctx, STACK_OF(CONF_VALUE) *nval);
71 static int i2r_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method,
72 void *a, BIO *bp, int ind);
73 static int do_i2r_name_constraints(const X509V3_EXT_METHOD *method,
74 STACK_OF(GENERAL_SUBTREE) *trees, BIO *bp, int ind, char *name);
75 static int print_nc_ipadd(BIO *bp, ASN1_OCTET_STRING *ip);
76
77 static int nc_match(GENERAL_NAME *gen, NAME_CONSTRAINTS *nc);
78 static int nc_match_single(GENERAL_NAME *sub, GENERAL_NAME *gen);
79 static int nc_dn(X509_NAME *sub, X509_NAME *nm);
80 static int nc_dns(ASN1_IA5STRING *sub, ASN1_IA5STRING *dns);
81 static int nc_email(ASN1_IA5STRING *sub, ASN1_IA5STRING *eml);
82 static int nc_uri(ASN1_IA5STRING *uri, ASN1_IA5STRING *base);
83
84 const X509V3_EXT_METHOD v3_name_constraints = {
85 .ext_nid = NID_name_constraints,
86 .ext_flags = 0,
87 .it = &NAME_CONSTRAINTS_it,
88 .ext_new = NULL,
89 .ext_free = NULL,
90 .d2i = NULL,
91 .i2d = NULL,
92 .i2s = NULL,
93 .s2i = NULL,
94 .i2v = NULL,
95 .v2i = v2i_NAME_CONSTRAINTS,
96 .i2r = i2r_NAME_CONSTRAINTS,
97 .r2i = NULL,
98 .usr_data = NULL,
99 };
100
101 static const ASN1_TEMPLATE GENERAL_SUBTREE_seq_tt[] = {
102 {
103 .flags = 0,
104 .tag = 0,
105 .offset = offsetof(GENERAL_SUBTREE, base),
106 .field_name = "base",
107 .item = &GENERAL_NAME_it,
108 },
109 {
110 .flags = ASN1_TFLG_IMPLICIT | ASN1_TFLG_OPTIONAL,
111 .tag = 0,
112 .offset = offsetof(GENERAL_SUBTREE, minimum),
113 .field_name = "minimum",
114 .item = &ASN1_INTEGER_it,
115 },
116 {
117 .flags = ASN1_TFLG_IMPLICIT | ASN1_TFLG_OPTIONAL,
118 .tag = 1,
119 .offset = offsetof(GENERAL_SUBTREE, maximum),
120 .field_name = "maximum",
121 .item = &ASN1_INTEGER_it,
122 },
123 };
124
125 const ASN1_ITEM GENERAL_SUBTREE_it = {
126 .itype = ASN1_ITYPE_SEQUENCE,
127 .utype = V_ASN1_SEQUENCE,
128 .templates = GENERAL_SUBTREE_seq_tt,
129 .tcount = sizeof(GENERAL_SUBTREE_seq_tt) / sizeof(ASN1_TEMPLATE),
130 .funcs = NULL,
131 .size = sizeof(GENERAL_SUBTREE),
132 .sname = "GENERAL_SUBTREE",
133 };
134
135 static const ASN1_TEMPLATE NAME_CONSTRAINTS_seq_tt[] = {
136 {
137 .flags = ASN1_TFLG_IMPLICIT | ASN1_TFLG_SEQUENCE_OF | ASN1_TFLG_OPTIONAL,
138 .tag = 0,
139 .offset = offsetof(NAME_CONSTRAINTS, permittedSubtrees),
140 .field_name = "permittedSubtrees",
141 .item = &GENERAL_SUBTREE_it,
142 },
143 {
144 .flags = ASN1_TFLG_IMPLICIT | ASN1_TFLG_SEQUENCE_OF | ASN1_TFLG_OPTIONAL,
145 .tag = 1,
146 .offset = offsetof(NAME_CONSTRAINTS, excludedSubtrees),
147 .field_name = "excludedSubtrees",
148 .item = &GENERAL_SUBTREE_it,
149 },
150 };
151
152 const ASN1_ITEM NAME_CONSTRAINTS_it = {
153 .itype = ASN1_ITYPE_SEQUENCE,
154 .utype = V_ASN1_SEQUENCE,
155 .templates = NAME_CONSTRAINTS_seq_tt,
156 .tcount = sizeof(NAME_CONSTRAINTS_seq_tt) / sizeof(ASN1_TEMPLATE),
157 .funcs = NULL,
158 .size = sizeof(NAME_CONSTRAINTS),
159 .sname = "NAME_CONSTRAINTS",
160 };
161
162
163 GENERAL_SUBTREE *
GENERAL_SUBTREE_new(void)164 GENERAL_SUBTREE_new(void)
165 {
166 return (GENERAL_SUBTREE*)ASN1_item_new(&GENERAL_SUBTREE_it);
167 }
168
169 void
GENERAL_SUBTREE_free(GENERAL_SUBTREE * a)170 GENERAL_SUBTREE_free(GENERAL_SUBTREE *a)
171 {
172 ASN1_item_free((ASN1_VALUE *)a, &GENERAL_SUBTREE_it);
173 }
174
175 NAME_CONSTRAINTS *
NAME_CONSTRAINTS_new(void)176 NAME_CONSTRAINTS_new(void)
177 {
178 return (NAME_CONSTRAINTS*)ASN1_item_new(&NAME_CONSTRAINTS_it);
179 }
180
181 void
NAME_CONSTRAINTS_free(NAME_CONSTRAINTS * a)182 NAME_CONSTRAINTS_free(NAME_CONSTRAINTS *a)
183 {
184 ASN1_item_free((ASN1_VALUE *)a, &NAME_CONSTRAINTS_it);
185 }
186
187 static void *
v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD * method,X509V3_CTX * ctx,STACK_OF (CONF_VALUE)* nval)188 v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, X509V3_CTX *ctx,
189 STACK_OF(CONF_VALUE) *nval)
190 {
191 int i;
192 CONF_VALUE tval, *val;
193 STACK_OF(GENERAL_SUBTREE) **ptree = NULL;
194 NAME_CONSTRAINTS *ncons = NULL;
195 GENERAL_SUBTREE *sub = NULL;
196
197 ncons = NAME_CONSTRAINTS_new();
198 if (!ncons)
199 goto memerr;
200 for (i = 0; i < sk_CONF_VALUE_num(nval); i++) {
201 val = sk_CONF_VALUE_value(nval, i);
202 if (!strncmp(val->name, "permitted", 9) && val->name[9]) {
203 ptree = &ncons->permittedSubtrees;
204 tval.name = val->name + 10;
205 } else if (!strncmp(val->name, "excluded", 8) && val->name[8]) {
206 ptree = &ncons->excludedSubtrees;
207 tval.name = val->name + 9;
208 } else {
209 X509V3error(X509V3_R_INVALID_SYNTAX);
210 goto err;
211 }
212 tval.value = val->value;
213 sub = GENERAL_SUBTREE_new();
214 if (!v2i_GENERAL_NAME_ex(sub->base, method, ctx, &tval, 1))
215 goto err;
216 if (!*ptree)
217 *ptree = sk_GENERAL_SUBTREE_new_null();
218 if (!*ptree || !sk_GENERAL_SUBTREE_push(*ptree, sub))
219 goto memerr;
220 sub = NULL;
221 }
222
223 return ncons;
224
225 memerr:
226 X509V3error(ERR_R_MALLOC_FAILURE);
227 err:
228 NAME_CONSTRAINTS_free(ncons);
229 GENERAL_SUBTREE_free(sub);
230 return NULL;
231 }
232
233 static int
i2r_NAME_CONSTRAINTS(const X509V3_EXT_METHOD * method,void * a,BIO * bp,int ind)234 i2r_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, void *a, BIO *bp, int ind)
235 {
236 NAME_CONSTRAINTS *ncons = a;
237
238 do_i2r_name_constraints(method, ncons->permittedSubtrees,
239 bp, ind, "Permitted");
240 do_i2r_name_constraints(method, ncons->excludedSubtrees,
241 bp, ind, "Excluded");
242 return 1;
243 }
244
245 static int
do_i2r_name_constraints(const X509V3_EXT_METHOD * method,STACK_OF (GENERAL_SUBTREE)* trees,BIO * bp,int ind,char * name)246 do_i2r_name_constraints(const X509V3_EXT_METHOD *method,
247 STACK_OF(GENERAL_SUBTREE) *trees, BIO *bp, int ind, char *name)
248 {
249 GENERAL_SUBTREE *tree;
250 int i;
251
252 if (sk_GENERAL_SUBTREE_num(trees) > 0)
253 BIO_printf(bp, "%*s%s:\n", ind, "", name);
254 for (i = 0; i < sk_GENERAL_SUBTREE_num(trees); i++) {
255 tree = sk_GENERAL_SUBTREE_value(trees, i);
256 BIO_printf(bp, "%*s", ind + 2, "");
257 if (tree->base->type == GEN_IPADD)
258 print_nc_ipadd(bp, tree->base->d.ip);
259 else
260 GENERAL_NAME_print(bp, tree->base);
261 BIO_puts(bp, "\n");
262 }
263 return 1;
264 }
265
266 static int
print_nc_ipadd(BIO * bp,ASN1_OCTET_STRING * ip)267 print_nc_ipadd(BIO *bp, ASN1_OCTET_STRING *ip)
268 {
269 int i, len;
270 unsigned char *p;
271
272 p = ip->data;
273 len = ip->length;
274 BIO_puts(bp, "IP:");
275 if (len == 8) {
276 BIO_printf(bp, "%d.%d.%d.%d/%d.%d.%d.%d",
277 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]);
278 } else if (len == 32) {
279 for (i = 0; i < 16; i++) {
280 BIO_printf(bp, "%X", p[0] << 8 | p[1]);
281 p += 2;
282 if (i == 7)
283 BIO_puts(bp, "/");
284 else if (i != 15)
285 BIO_puts(bp, ":");
286 }
287 } else
288 BIO_printf(bp, "IP Address:<invalid>");
289 return 1;
290 }
291
292 /* Check a certificate conforms to a specified set of constraints.
293 * Return values:
294 * X509_V_OK: All constraints obeyed.
295 * X509_V_ERR_PERMITTED_VIOLATION: Permitted subtree violation.
296 * X509_V_ERR_EXCLUDED_VIOLATION: Excluded subtree violation.
297 * X509_V_ERR_SUBTREE_MINMAX: Min or max values present and matching type.
298 * X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE: Unsupported constraint type.
299 * X509_V_ERR_UNSUPPORTED_CONSTRAINT_SYNTAX: bad unsupported constraint syntax.
300 * X509_V_ERR_UNSUPPORTED_NAME_SYNTAX: bad or unsupported syntax of name
301 */
302
303 int
NAME_CONSTRAINTS_check(X509 * x,NAME_CONSTRAINTS * nc)304 NAME_CONSTRAINTS_check(X509 *x, NAME_CONSTRAINTS *nc)
305 {
306 int r, i;
307 X509_NAME *nm;
308
309 nm = X509_get_subject_name(x);
310
311 if (X509_NAME_entry_count(nm) > 0) {
312 GENERAL_NAME gntmp;
313 gntmp.type = GEN_DIRNAME;
314 gntmp.d.directoryName = nm;
315
316 r = nc_match(&gntmp, nc);
317
318 if (r != X509_V_OK)
319 return r;
320
321 gntmp.type = GEN_EMAIL;
322
323 /* Process any email address attributes in subject name */
324
325 for (i = -1;;) {
326 X509_NAME_ENTRY *ne;
327 i = X509_NAME_get_index_by_NID(nm,
328 NID_pkcs9_emailAddress, i);
329 if (i == -1)
330 break;
331 ne = X509_NAME_get_entry(nm, i);
332 gntmp.d.rfc822Name = X509_NAME_ENTRY_get_data(ne);
333 if (gntmp.d.rfc822Name->type != V_ASN1_IA5STRING)
334 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
335
336 r = nc_match(&gntmp, nc);
337
338 if (r != X509_V_OK)
339 return r;
340 }
341
342 }
343
344 for (i = 0; i < sk_GENERAL_NAME_num(x->altname); i++) {
345 GENERAL_NAME *gen = sk_GENERAL_NAME_value(x->altname, i);
346 r = nc_match(gen, nc);
347 if (r != X509_V_OK)
348 return r;
349 }
350 return X509_V_OK;
351 }
352 static int
nc_match(GENERAL_NAME * gen,NAME_CONSTRAINTS * nc)353 nc_match(GENERAL_NAME *gen, NAME_CONSTRAINTS *nc)
354 {
355 GENERAL_SUBTREE *sub;
356 int i, r, match = 0;
357
358 /* Permitted subtrees: if any subtrees exist of matching the type
359 * at least one subtree must match.
360 */
361
362 for (i = 0; i < sk_GENERAL_SUBTREE_num(nc->permittedSubtrees); i++) {
363 sub = sk_GENERAL_SUBTREE_value(nc->permittedSubtrees, i);
364 if (gen->type != sub->base->type)
365 continue;
366 if (sub->minimum || sub->maximum)
367 return X509_V_ERR_SUBTREE_MINMAX;
368 /* If we already have a match don't bother trying any more */
369 if (match == 2)
370 continue;
371 if (match == 0)
372 match = 1;
373 r = nc_match_single(gen, sub->base);
374 if (r == X509_V_OK)
375 match = 2;
376 else if (r != X509_V_ERR_PERMITTED_VIOLATION)
377 return r;
378 }
379
380 if (match == 1)
381 return X509_V_ERR_PERMITTED_VIOLATION;
382
383 /* Excluded subtrees: must not match any of these */
384
385 for (i = 0; i < sk_GENERAL_SUBTREE_num(nc->excludedSubtrees); i++) {
386 sub = sk_GENERAL_SUBTREE_value(nc->excludedSubtrees, i);
387 if (gen->type != sub->base->type)
388 continue;
389 if (sub->minimum || sub->maximum)
390 return X509_V_ERR_SUBTREE_MINMAX;
391
392 r = nc_match_single(gen, sub->base);
393 if (r == X509_V_OK)
394 return X509_V_ERR_EXCLUDED_VIOLATION;
395 else if (r != X509_V_ERR_PERMITTED_VIOLATION)
396 return r;
397
398 }
399
400 return X509_V_OK;
401 }
402
403 static int
nc_match_single(GENERAL_NAME * gen,GENERAL_NAME * base)404 nc_match_single(GENERAL_NAME *gen, GENERAL_NAME *base)
405 {
406 switch (base->type) {
407 case GEN_DIRNAME:
408 return nc_dn(gen->d.directoryName, base->d.directoryName);
409
410 case GEN_DNS:
411 return nc_dns(gen->d.dNSName, base->d.dNSName);
412
413 case GEN_EMAIL:
414 return nc_email(gen->d.rfc822Name, base->d.rfc822Name);
415
416 case GEN_URI:
417 return nc_uri(gen->d.uniformResourceIdentifier,
418 base->d.uniformResourceIdentifier);
419
420 default:
421 return X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE;
422 }
423 }
424
425 /* directoryName name constraint matching.
426 * The canonical encoding of X509_NAME makes this comparison easy. It is
427 * matched if the subtree is a subset of the name.
428 */
429
430 static int
nc_dn(X509_NAME * nm,X509_NAME * base)431 nc_dn(X509_NAME *nm, X509_NAME *base)
432 {
433 /* Ensure canonical encodings are up to date. */
434 if (nm->modified && i2d_X509_NAME(nm, NULL) < 0)
435 return X509_V_ERR_OUT_OF_MEM;
436 if (base->modified && i2d_X509_NAME(base, NULL) < 0)
437 return X509_V_ERR_OUT_OF_MEM;
438 if (base->canon_enclen > nm->canon_enclen)
439 return X509_V_ERR_PERMITTED_VIOLATION;
440 if (memcmp(base->canon_enc, nm->canon_enc, base->canon_enclen))
441 return X509_V_ERR_PERMITTED_VIOLATION;
442 return X509_V_OK;
443 }
444
445 static int
nc_dns(ASN1_IA5STRING * dns,ASN1_IA5STRING * base)446 nc_dns(ASN1_IA5STRING *dns, ASN1_IA5STRING *base)
447 {
448 char *baseptr = (char *)base->data;
449 char *dnsptr = (char *)dns->data;
450
451 /* Empty matches everything */
452 if (!*baseptr)
453 return X509_V_OK;
454 /* Otherwise can add zero or more components on the left so
455 * compare RHS and if dns is longer and expect '.' as preceding
456 * character.
457 */
458 if (dns->length > base->length) {
459 dnsptr += dns->length - base->length;
460 if (baseptr[0] != '.' && dnsptr[-1] != '.')
461 return X509_V_ERR_PERMITTED_VIOLATION;
462 }
463
464 if (strcasecmp(baseptr, dnsptr))
465 return X509_V_ERR_PERMITTED_VIOLATION;
466
467 return X509_V_OK;
468 }
469
470 static int
nc_email(ASN1_IA5STRING * eml,ASN1_IA5STRING * base)471 nc_email(ASN1_IA5STRING *eml, ASN1_IA5STRING *base)
472 {
473 const char *baseptr = (char *)base->data;
474 const char *emlptr = (char *)eml->data;
475 const char *baseat = strchr(baseptr, '@');
476 const char *emlat = strchr(emlptr, '@');
477
478 if (!emlat)
479 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
480 /* Special case: inital '.' is RHS match */
481 if (!baseat && (*baseptr == '.')) {
482 if (eml->length > base->length) {
483 emlptr += eml->length - base->length;
484 if (!strcasecmp(baseptr, emlptr))
485 return X509_V_OK;
486 }
487 return X509_V_ERR_PERMITTED_VIOLATION;
488 }
489
490 /* If we have anything before '@' match local part */
491
492 if (baseat) {
493 if (baseat != baseptr) {
494 if ((baseat - baseptr) != (emlat - emlptr))
495 return X509_V_ERR_PERMITTED_VIOLATION;
496 /* Case sensitive match of local part */
497 if (strncmp(baseptr, emlptr, emlat - emlptr))
498 return X509_V_ERR_PERMITTED_VIOLATION;
499 }
500 /* Position base after '@' */
501 baseptr = baseat + 1;
502 }
503 emlptr = emlat + 1;
504 /* Just have hostname left to match: case insensitive */
505 if (strcasecmp(baseptr, emlptr))
506 return X509_V_ERR_PERMITTED_VIOLATION;
507
508 return X509_V_OK;
509 }
510
511 static int
nc_uri(ASN1_IA5STRING * uri,ASN1_IA5STRING * base)512 nc_uri(ASN1_IA5STRING *uri, ASN1_IA5STRING *base)
513 {
514 const char *baseptr = (char *)base->data;
515 const char *hostptr = (char *)uri->data;
516 const char *p = strchr(hostptr, ':');
517 int hostlen;
518
519 /* Check for foo:// and skip past it */
520 if (!p || (p[1] != '/') || (p[2] != '/'))
521 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
522 hostptr = p + 3;
523
524 /* Determine length of hostname part of URI */
525
526 /* Look for a port indicator as end of hostname first */
527
528 p = strchr(hostptr, ':');
529 /* Otherwise look for trailing slash */
530 if (!p)
531 p = strchr(hostptr, '/');
532
533 if (!p)
534 hostlen = strlen(hostptr);
535 else
536 hostlen = p - hostptr;
537
538 if (hostlen == 0)
539 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
540
541 /* Special case: inital '.' is RHS match */
542 if (*baseptr == '.') {
543 if (hostlen > base->length) {
544 p = hostptr + hostlen - base->length;
545 if (!strncasecmp(p, baseptr, base->length))
546 return X509_V_OK;
547 }
548 return X509_V_ERR_PERMITTED_VIOLATION;
549 }
550
551 if ((base->length != (int)hostlen) ||
552 strncasecmp(hostptr, baseptr, hostlen))
553 return X509_V_ERR_PERMITTED_VIOLATION;
554
555 return X509_V_OK;
556 }
557