2 * Copyright 2003-2018 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
10 #include "internal/cryptlib.h"
11 #include "internal/numbers.h"
13 #include "internal/asn1_int.h"
14 #include <openssl/asn1t.h>
15 #include <openssl/conf.h>
16 #include <openssl/x509v3.h>
18 #include "internal/x509_int.h"
21 static void *v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method,
23 STACK_OF(CONF_VALUE) *nval);
24 static int i2r_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, void *a,
26 static int do_i2r_name_constraints(const X509V3_EXT_METHOD *method,
27 STACK_OF(GENERAL_SUBTREE) *trees, BIO *bp,
28 int ind, const char *name);
29 static int print_nc_ipadd(BIO *bp, ASN1_OCTET_STRING *ip);
31 static int nc_match(GENERAL_NAME *gen, NAME_CONSTRAINTS *nc);
32 static int nc_match_single(GENERAL_NAME *sub, GENERAL_NAME *gen);
33 static int nc_dn(X509_NAME *sub, X509_NAME *nm);
34 static int nc_dns(ASN1_IA5STRING *sub, ASN1_IA5STRING *dns);
35 static int nc_email(ASN1_IA5STRING *sub, ASN1_IA5STRING *eml);
36 static int nc_uri(ASN1_IA5STRING *uri, ASN1_IA5STRING *base);
37 static int nc_ip(ASN1_OCTET_STRING *ip, ASN1_OCTET_STRING *base);
39 const X509V3_EXT_METHOD v3_name_constraints = {
40 NID_name_constraints, 0,
41 ASN1_ITEM_ref(NAME_CONSTRAINTS),
44 0, v2i_NAME_CONSTRAINTS,
45 i2r_NAME_CONSTRAINTS, 0,
49 ASN1_SEQUENCE(GENERAL_SUBTREE) = {
50 ASN1_SIMPLE(GENERAL_SUBTREE, base, GENERAL_NAME),
51 ASN1_IMP_OPT(GENERAL_SUBTREE, minimum, ASN1_INTEGER, 0),
52 ASN1_IMP_OPT(GENERAL_SUBTREE, maximum, ASN1_INTEGER, 1)
53 } ASN1_SEQUENCE_END(GENERAL_SUBTREE)
55 ASN1_SEQUENCE(NAME_CONSTRAINTS) = {
56 ASN1_IMP_SEQUENCE_OF_OPT(NAME_CONSTRAINTS, permittedSubtrees,
58 ASN1_IMP_SEQUENCE_OF_OPT(NAME_CONSTRAINTS, excludedSubtrees,
60 } ASN1_SEQUENCE_END(NAME_CONSTRAINTS)
63 IMPLEMENT_ASN1_ALLOC_FUNCTIONS(GENERAL_SUBTREE)
64 IMPLEMENT_ASN1_ALLOC_FUNCTIONS(NAME_CONSTRAINTS)
67 * We cannot use strncasecmp here because that applies locale specific rules.
68 * For example in Turkish 'I' is not the uppercase character for 'i'. We need to
69 * do a simple ASCII case comparison ignoring the locale (that is why we use
70 * numeric constants below).
72 static int ia5ncasecmp(const char *s1, const char *s2, size_t n)
74 for (; n > 0; n--, s1++, s2++) {
76 unsigned char c1 = (unsigned char)*s1, c2 = (unsigned char)*s2;
78 /* Convert to lower case */
79 if (c1 >= 0x41 /* A */ && c1 <= 0x5A /* Z */)
81 if (c2 >= 0x41 /* A */ && c2 <= 0x5A /* Z */)
92 } else if (*s1 == 0) {
93 /* If we get here we know that *s2 == 0 too */
101 static int ia5casecmp(const char *s1, const char *s2)
103 return ia5ncasecmp(s1, s2, SIZE_MAX);
106 static void *v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method,
107 X509V3_CTX *ctx, STACK_OF(CONF_VALUE) *nval)
110 CONF_VALUE tval, *val;
111 STACK_OF(GENERAL_SUBTREE) **ptree = NULL;
112 NAME_CONSTRAINTS *ncons = NULL;
113 GENERAL_SUBTREE *sub = NULL;
115 ncons = NAME_CONSTRAINTS_new();
118 for (i = 0; i < sk_CONF_VALUE_num(nval); i++) {
119 val = sk_CONF_VALUE_value(nval, i);
120 if (strncmp(val->name, "permitted", 9) == 0 && val->name[9]) {
121 ptree = &ncons->permittedSubtrees;
122 tval.name = val->name + 10;
123 } else if (strncmp(val->name, "excluded", 8) == 0 && val->name[8]) {
124 ptree = &ncons->excludedSubtrees;
125 tval.name = val->name + 9;
127 X509V3err(X509V3_F_V2I_NAME_CONSTRAINTS, X509V3_R_INVALID_SYNTAX);
130 tval.value = val->value;
131 sub = GENERAL_SUBTREE_new();
134 if (!v2i_GENERAL_NAME_ex(sub->base, method, ctx, &tval, 1))
137 *ptree = sk_GENERAL_SUBTREE_new_null();
138 if (*ptree == NULL || !sk_GENERAL_SUBTREE_push(*ptree, sub))
146 X509V3err(X509V3_F_V2I_NAME_CONSTRAINTS, ERR_R_MALLOC_FAILURE);
148 NAME_CONSTRAINTS_free(ncons);
149 GENERAL_SUBTREE_free(sub);
154 static int i2r_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, void *a,
157 NAME_CONSTRAINTS *ncons = a;
158 do_i2r_name_constraints(method, ncons->permittedSubtrees,
159 bp, ind, "Permitted");
160 do_i2r_name_constraints(method, ncons->excludedSubtrees,
161 bp, ind, "Excluded");
165 static int do_i2r_name_constraints(const X509V3_EXT_METHOD *method,
166 STACK_OF(GENERAL_SUBTREE) *trees,
167 BIO *bp, int ind, const char *name)
169 GENERAL_SUBTREE *tree;
171 if (sk_GENERAL_SUBTREE_num(trees) > 0)
172 BIO_printf(bp, "%*s%s:\n", ind, "", name);
173 for (i = 0; i < sk_GENERAL_SUBTREE_num(trees); i++) {
174 tree = sk_GENERAL_SUBTREE_value(trees, i);
175 BIO_printf(bp, "%*s", ind + 2, "");
176 if (tree->base->type == GEN_IPADD)
177 print_nc_ipadd(bp, tree->base->d.ip);
179 GENERAL_NAME_print(bp, tree->base);
185 static int print_nc_ipadd(BIO *bp, ASN1_OCTET_STRING *ip)
193 BIO_printf(bp, "%d.%d.%d.%d/%d.%d.%d.%d",
194 p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]);
195 } else if (len == 32) {
196 for (i = 0; i < 16; i++) {
197 BIO_printf(bp, "%X", p[0] << 8 | p[1]);
205 BIO_printf(bp, "IP Address:<invalid>");
209 #define NAME_CHECK_MAX (1 << 20)
211 static int add_lengths(int *out, int a, int b)
213 /* sk_FOO_num(NULL) returns -1 but is effectively 0 when iterating. */
226 * Check a certificate conforms to a specified set of constraints.
228 * X509_V_OK: All constraints obeyed.
229 * X509_V_ERR_PERMITTED_VIOLATION: Permitted subtree violation.
230 * X509_V_ERR_EXCLUDED_VIOLATION: Excluded subtree violation.
231 * X509_V_ERR_SUBTREE_MINMAX: Min or max values present and matching type.
232 * X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE: Unsupported constraint type.
233 * X509_V_ERR_UNSUPPORTED_CONSTRAINT_SYNTAX: bad unsupported constraint syntax.
234 * X509_V_ERR_UNSUPPORTED_NAME_SYNTAX: bad or unsupported syntax of name
237 int NAME_CONSTRAINTS_check(X509 *x, NAME_CONSTRAINTS *nc)
239 int r, i, name_count, constraint_count;
242 nm = X509_get_subject_name(x);
245 * Guard against certificates with an excessive number of names or
246 * constraints causing a computationally expensive name constraints check.
248 if (!add_lengths(&name_count, X509_NAME_entry_count(nm),
249 sk_GENERAL_NAME_num(x->altname))
250 || !add_lengths(&constraint_count,
251 sk_GENERAL_SUBTREE_num(nc->permittedSubtrees),
252 sk_GENERAL_SUBTREE_num(nc->excludedSubtrees))
253 || (name_count > 0 && constraint_count > NAME_CHECK_MAX / name_count))
254 return X509_V_ERR_UNSPECIFIED;
256 if (X509_NAME_entry_count(nm) > 0) {
258 gntmp.type = GEN_DIRNAME;
259 gntmp.d.directoryName = nm;
261 r = nc_match(&gntmp, nc);
266 gntmp.type = GEN_EMAIL;
268 /* Process any email address attributes in subject name */
271 const X509_NAME_ENTRY *ne;
273 i = X509_NAME_get_index_by_NID(nm, NID_pkcs9_emailAddress, i);
276 ne = X509_NAME_get_entry(nm, i);
277 gntmp.d.rfc822Name = X509_NAME_ENTRY_get_data(ne);
278 if (gntmp.d.rfc822Name->type != V_ASN1_IA5STRING)
279 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
281 r = nc_match(&gntmp, nc);
289 for (i = 0; i < sk_GENERAL_NAME_num(x->altname); i++) {
290 GENERAL_NAME *gen = sk_GENERAL_NAME_value(x->altname, i);
291 r = nc_match(gen, nc);
300 static int cn2dnsid(ASN1_STRING *cn, unsigned char **dnsid, size_t *idlen)
303 unsigned char *utf8_value;
307 /* Don't leave outputs uninitialized */
312 * Per RFC 6125, DNS-IDs representing internationalized domain names appear
313 * in certificates in A-label encoded form:
315 * https://tools.ietf.org/html/rfc6125#section-6.4.2
317 * The same applies to CNs which are intended to represent DNS names.
318 * However, while in the SAN DNS-IDs are IA5Strings, as CNs they may be
319 * needlessly encoded in 16-bit Unicode. We perform a conversion to UTF-8
320 * to ensure that we get an ASCII representation of any CNs that are
321 * representable as ASCII, but just not encoded as ASCII. The UTF-8 form
322 * may contain some non-ASCII octets, and that's fine, such CNs are not
323 * valid legacy DNS names.
325 * Note, 'int' is the return type of ASN1_STRING_to_UTF8() so that's what
326 * we must use for 'utf8_length'.
328 if ((utf8_length = ASN1_STRING_to_UTF8(&utf8_value, cn)) < 0)
329 return X509_V_ERR_OUT_OF_MEM;
332 * Some certificates have had names that include a *trailing* NUL byte.
333 * Remove these harmless NUL characters. They would otherwise yield false
334 * alarms with the following embedded NUL check.
336 while (utf8_length > 0 && utf8_value[utf8_length - 1] == '\0')
339 /* Reject *embedded* NULs */
340 if ((size_t)utf8_length != strlen((char *)utf8_value)) {
341 OPENSSL_free(utf8_value);
342 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
346 * XXX: Deviation from strict DNS name syntax, also check names with '_'
347 * Check DNS name syntax, any '-' or '.' must be internal,
348 * and on either side of each '.' we can't have a '-' or '.'.
350 * If the name has just one label, we don't consider it a DNS name. This
351 * means that "CN=sometld" cannot be precluded by DNS name constraints, but
352 * that is not a problem.
354 for (i = 0; i < utf8_length; ++i) {
355 unsigned char c = utf8_value[i];
357 if ((c >= 'a' && c <= 'z')
358 || (c >= 'A' && c <= 'Z')
359 || (c >= '0' && c <= '9')
363 /* Dot and hyphen cannot be first or last. */
364 if (i > 0 && i < utf8_length - 1) {
368 * Next to a dot the preceding and following characters must not be
369 * another dot or a hyphen. Otherwise, record that the name is
370 * plausible, since it has two or more labels.
373 && utf8_value[i + 1] != '.'
374 && utf8_value[i - 1] != '-'
375 && utf8_value[i + 1] != '-') {
386 *idlen = (size_t)utf8_length;
389 OPENSSL_free(utf8_value);
394 * Check CN against DNS-ID name constraints.
396 int NAME_CONSTRAINTS_check_CN(X509 *x, NAME_CONSTRAINTS *nc)
399 X509_NAME *nm = X509_get_subject_name(x);
404 stmp.type = V_ASN1_IA5STRING;
405 gntmp.type = GEN_DNS;
406 gntmp.d.dNSName = &stmp;
408 /* Process any commonName attributes in subject name */
413 unsigned char *idval;
416 i = X509_NAME_get_index_by_NID(nm, NID_commonName, i);
419 ne = X509_NAME_get_entry(nm, i);
420 cn = X509_NAME_ENTRY_get_data(ne);
422 /* Only process attributes that look like host names */
423 if ((r = cn2dnsid(cn, &idval, &idlen)) != X509_V_OK)
430 r = nc_match(&gntmp, nc);
438 static int nc_match(GENERAL_NAME *gen, NAME_CONSTRAINTS *nc)
440 GENERAL_SUBTREE *sub;
444 * Permitted subtrees: if any subtrees exist of matching the type at
445 * least one subtree must match.
448 for (i = 0; i < sk_GENERAL_SUBTREE_num(nc->permittedSubtrees); i++) {
449 sub = sk_GENERAL_SUBTREE_value(nc->permittedSubtrees, i);
450 if (gen->type != sub->base->type)
452 if (sub->minimum || sub->maximum)
453 return X509_V_ERR_SUBTREE_MINMAX;
454 /* If we already have a match don't bother trying any more */
459 r = nc_match_single(gen, sub->base);
462 else if (r != X509_V_ERR_PERMITTED_VIOLATION)
467 return X509_V_ERR_PERMITTED_VIOLATION;
469 /* Excluded subtrees: must not match any of these */
471 for (i = 0; i < sk_GENERAL_SUBTREE_num(nc->excludedSubtrees); i++) {
472 sub = sk_GENERAL_SUBTREE_value(nc->excludedSubtrees, i);
473 if (gen->type != sub->base->type)
475 if (sub->minimum || sub->maximum)
476 return X509_V_ERR_SUBTREE_MINMAX;
478 r = nc_match_single(gen, sub->base);
480 return X509_V_ERR_EXCLUDED_VIOLATION;
481 else if (r != X509_V_ERR_PERMITTED_VIOLATION)
490 static int nc_match_single(GENERAL_NAME *gen, GENERAL_NAME *base)
492 switch (base->type) {
494 return nc_dn(gen->d.directoryName, base->d.directoryName);
497 return nc_dns(gen->d.dNSName, base->d.dNSName);
500 return nc_email(gen->d.rfc822Name, base->d.rfc822Name);
503 return nc_uri(gen->d.uniformResourceIdentifier,
504 base->d.uniformResourceIdentifier);
507 return nc_ip(gen->d.iPAddress, base->d.iPAddress);
510 return X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE;
516 * directoryName name constraint matching. The canonical encoding of
517 * X509_NAME makes this comparison easy. It is matched if the subtree is a
518 * subset of the name.
521 static int nc_dn(X509_NAME *nm, X509_NAME *base)
523 /* Ensure canonical encodings are up to date. */
524 if (nm->modified && i2d_X509_NAME(nm, NULL) < 0)
525 return X509_V_ERR_OUT_OF_MEM;
526 if (base->modified && i2d_X509_NAME(base, NULL) < 0)
527 return X509_V_ERR_OUT_OF_MEM;
528 if (base->canon_enclen > nm->canon_enclen)
529 return X509_V_ERR_PERMITTED_VIOLATION;
530 if (memcmp(base->canon_enc, nm->canon_enc, base->canon_enclen))
531 return X509_V_ERR_PERMITTED_VIOLATION;
535 static int nc_dns(ASN1_IA5STRING *dns, ASN1_IA5STRING *base)
537 char *baseptr = (char *)base->data;
538 char *dnsptr = (char *)dns->data;
539 /* Empty matches everything */
543 * Otherwise can add zero or more components on the left so compare RHS
544 * and if dns is longer and expect '.' as preceding character.
546 if (dns->length > base->length) {
547 dnsptr += dns->length - base->length;
548 if (*baseptr != '.' && dnsptr[-1] != '.')
549 return X509_V_ERR_PERMITTED_VIOLATION;
552 if (ia5casecmp(baseptr, dnsptr))
553 return X509_V_ERR_PERMITTED_VIOLATION;
559 static int nc_email(ASN1_IA5STRING *eml, ASN1_IA5STRING *base)
561 const char *baseptr = (char *)base->data;
562 const char *emlptr = (char *)eml->data;
564 const char *baseat = strchr(baseptr, '@');
565 const char *emlat = strchr(emlptr, '@');
567 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
568 /* Special case: initial '.' is RHS match */
569 if (!baseat && (*baseptr == '.')) {
570 if (eml->length > base->length) {
571 emlptr += eml->length - base->length;
572 if (ia5casecmp(baseptr, emlptr) == 0)
575 return X509_V_ERR_PERMITTED_VIOLATION;
578 /* If we have anything before '@' match local part */
581 if (baseat != baseptr) {
582 if ((baseat - baseptr) != (emlat - emlptr))
583 return X509_V_ERR_PERMITTED_VIOLATION;
584 /* Case sensitive match of local part */
585 if (strncmp(baseptr, emlptr, emlat - emlptr))
586 return X509_V_ERR_PERMITTED_VIOLATION;
588 /* Position base after '@' */
589 baseptr = baseat + 1;
592 /* Just have hostname left to match: case insensitive */
593 if (ia5casecmp(baseptr, emlptr))
594 return X509_V_ERR_PERMITTED_VIOLATION;
600 static int nc_uri(ASN1_IA5STRING *uri, ASN1_IA5STRING *base)
602 const char *baseptr = (char *)base->data;
603 const char *hostptr = (char *)uri->data;
604 const char *p = strchr(hostptr, ':');
606 /* Check for foo:// and skip past it */
607 if (!p || (p[1] != '/') || (p[2] != '/'))
608 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
611 /* Determine length of hostname part of URI */
613 /* Look for a port indicator as end of hostname first */
615 p = strchr(hostptr, ':');
616 /* Otherwise look for trailing slash */
618 p = strchr(hostptr, '/');
621 hostlen = strlen(hostptr);
623 hostlen = p - hostptr;
626 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
628 /* Special case: initial '.' is RHS match */
629 if (*baseptr == '.') {
630 if (hostlen > base->length) {
631 p = hostptr + hostlen - base->length;
632 if (ia5ncasecmp(p, baseptr, base->length) == 0)
635 return X509_V_ERR_PERMITTED_VIOLATION;
638 if ((base->length != (int)hostlen)
639 || ia5ncasecmp(hostptr, baseptr, hostlen))
640 return X509_V_ERR_PERMITTED_VIOLATION;
646 static int nc_ip(ASN1_OCTET_STRING *ip, ASN1_OCTET_STRING *base)
648 int hostlen, baselen, i;
649 unsigned char *hostptr, *baseptr, *maskptr;
651 hostlen = ip->length;
652 baseptr = base->data;
653 baselen = base->length;
655 /* Invalid if not IPv4 or IPv6 */
656 if (!((hostlen == 4) || (hostlen == 16)))
657 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
658 if (!((baselen == 8) || (baselen == 32)))
659 return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
661 /* Do not match IPv4 with IPv6 */
662 if (hostlen * 2 != baselen)
663 return X509_V_ERR_PERMITTED_VIOLATION;
665 maskptr = base->data + hostlen;
667 /* Considering possible not aligned base ipAddress */
668 /* Not checking for wrong mask definition: i.e.: 255.0.255.0 */
669 for (i = 0; i < hostlen; i++)
670 if ((hostptr[i] & maskptr[i]) != (baseptr[i] & maskptr[i]))
671 return X509_V_ERR_PERMITTED_VIOLATION;