diff options
Diffstat (limited to 'src/crypto/x509/v3_ncons.c')
| -rw-r--r-- | src/crypto/x509/v3_ncons.c | 555 |
1 files changed, 555 insertions, 0 deletions
diff --git a/src/crypto/x509/v3_ncons.c b/src/crypto/x509/v3_ncons.c new file mode 100644 index 0000000..31ef58d --- /dev/null +++ b/src/crypto/x509/v3_ncons.c @@ -0,0 +1,555 @@ +/* + * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL + * project. + */ +/* ==================================================================== + * Copyright (c) 2003 The OpenSSL Project. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * + * 3. All advertising materials mentioning features or use of this + * software must display the following acknowledgment: + * "This product includes software developed by the OpenSSL Project + * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)" + * + * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to + * endorse or promote products derived from this software without + * prior written permission. For written permission, please contact + * licensing@OpenSSL.org. + * + * 5. Products derived from this software may not be called "OpenSSL" + * nor may "OpenSSL" appear in their names without prior written + * permission of the OpenSSL Project. + * + * 6. Redistributions of any form whatsoever must retain the following + * acknowledgment: + * "This product includes software developed by the OpenSSL Project + * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)" + * + * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY + * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR + * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, + * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED + * OF THE POSSIBILITY OF SUCH DAMAGE. + * ==================================================================== + * + * This product includes cryptographic software written by Eric Young + * (eay@cryptsoft.com). This product includes software written by Tim + * Hudson (tjh@cryptsoft.com). */ + +#include <stdio.h> +#include <string.h> + +#include <openssl/asn1t.h> +#include <openssl/conf.h> +#include <openssl/err.h> +#include <openssl/mem.h> +#include <openssl/obj.h> +#include <openssl/x509.h> + +#include "../internal.h" +#include "internal.h" + + +static void *v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, + const X509V3_CTX *ctx, + const STACK_OF(CONF_VALUE) *nval); +static int i2r_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, void *a, + BIO *bp, int ind); +static int do_i2r_name_constraints(const X509V3_EXT_METHOD *method, + STACK_OF(GENERAL_SUBTREE) *trees, BIO *bp, + int ind, const char *name); +static int print_nc_ipadd(BIO *bp, const ASN1_OCTET_STRING *ip); + +static int nc_match(GENERAL_NAME *gen, NAME_CONSTRAINTS *nc); +static int nc_match_single(GENERAL_NAME *sub, GENERAL_NAME *gen); +static int nc_dn(X509_NAME *sub, X509_NAME *nm); +static int nc_dns(const ASN1_IA5STRING *sub, const ASN1_IA5STRING *dns); +static int nc_email(const ASN1_IA5STRING *sub, const ASN1_IA5STRING *eml); +static int nc_uri(const ASN1_IA5STRING *uri, const ASN1_IA5STRING *base); + +const X509V3_EXT_METHOD v3_name_constraints = { + NID_name_constraints, + 0, + ASN1_ITEM_ref(NAME_CONSTRAINTS), + 0, + 0, + 0, + 0, + 0, + 0, + 0, + v2i_NAME_CONSTRAINTS, + i2r_NAME_CONSTRAINTS, + 0, + NULL, +}; + +ASN1_SEQUENCE(GENERAL_SUBTREE) = { + ASN1_SIMPLE(GENERAL_SUBTREE, base, GENERAL_NAME), + ASN1_IMP_OPT(GENERAL_SUBTREE, minimum, ASN1_INTEGER, 0), + ASN1_IMP_OPT(GENERAL_SUBTREE, maximum, ASN1_INTEGER, 1), +} ASN1_SEQUENCE_END(GENERAL_SUBTREE) + +ASN1_SEQUENCE(NAME_CONSTRAINTS) = { + ASN1_IMP_SEQUENCE_OF_OPT(NAME_CONSTRAINTS, permittedSubtrees, + GENERAL_SUBTREE, 0), + ASN1_IMP_SEQUENCE_OF_OPT(NAME_CONSTRAINTS, excludedSubtrees, + GENERAL_SUBTREE, 1), +} ASN1_SEQUENCE_END(NAME_CONSTRAINTS) + + +IMPLEMENT_ASN1_ALLOC_FUNCTIONS(GENERAL_SUBTREE) +IMPLEMENT_ASN1_ALLOC_FUNCTIONS(NAME_CONSTRAINTS) + +static void *v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, + const X509V3_CTX *ctx, + const STACK_OF(CONF_VALUE) *nval) { + STACK_OF(GENERAL_SUBTREE) **ptree = NULL; + NAME_CONSTRAINTS *ncons = NULL; + GENERAL_SUBTREE *sub = NULL; + ncons = NAME_CONSTRAINTS_new(); + if (!ncons) { + goto err; + } + for (size_t i = 0; i < sk_CONF_VALUE_num(nval); i++) { + const CONF_VALUE *val = sk_CONF_VALUE_value(nval, i); + CONF_VALUE tval; + if (!strncmp(val->name, "permitted", 9) && val->name[9]) { + ptree = &ncons->permittedSubtrees; + tval.name = val->name + 10; + } else if (!strncmp(val->name, "excluded", 8) && val->name[8]) { + ptree = &ncons->excludedSubtrees; + tval.name = val->name + 9; + } else { + OPENSSL_PUT_ERROR(X509V3, X509V3_R_INVALID_SYNTAX); + goto err; + } + tval.value = val->value; + sub = GENERAL_SUBTREE_new(); + if (!v2i_GENERAL_NAME_ex(sub->base, method, ctx, &tval, 1)) { + goto err; + } + if (!*ptree) { + *ptree = sk_GENERAL_SUBTREE_new_null(); + } + if (!*ptree || !sk_GENERAL_SUBTREE_push(*ptree, sub)) { + goto err; + } + sub = NULL; + } + + return ncons; + +err: + NAME_CONSTRAINTS_free(ncons); + GENERAL_SUBTREE_free(sub); + return NULL; +} + +static int i2r_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method, void *a, + BIO *bp, int ind) { + NAME_CONSTRAINTS *ncons = a; + do_i2r_name_constraints(method, ncons->permittedSubtrees, bp, ind, + "Permitted"); + do_i2r_name_constraints(method, ncons->excludedSubtrees, bp, ind, "Excluded"); + return 1; +} + +static int do_i2r_name_constraints(const X509V3_EXT_METHOD *method, + STACK_OF(GENERAL_SUBTREE) *trees, BIO *bp, + int ind, const char *name) { + GENERAL_SUBTREE *tree; + size_t i; + if (sk_GENERAL_SUBTREE_num(trees) > 0) { + BIO_printf(bp, "%*s%s:\n", ind, "", name); + } + for (i = 0; i < sk_GENERAL_SUBTREE_num(trees); i++) { + tree = sk_GENERAL_SUBTREE_value(trees, i); + BIO_printf(bp, "%*s", ind + 2, ""); + if (tree->base->type == GEN_IPADD) { + print_nc_ipadd(bp, tree->base->d.ip); + } else { + GENERAL_NAME_print(bp, tree->base); + } + BIO_puts(bp, "\n"); + } + return 1; +} + +static int print_nc_ipadd(BIO *bp, const ASN1_OCTET_STRING *ip) { + int i, len; + unsigned char *p; + p = ip->data; + len = ip->length; + BIO_puts(bp, "IP:"); + if (len == 8) { + BIO_printf(bp, "%d.%d.%d.%d/%d.%d.%d.%d", p[0], p[1], p[2], p[3], p[4], + p[5], p[6], p[7]); + } else if (len == 32) { + for (i = 0; i < 16; i++) { + uint16_t v = ((uint16_t)p[0] << 8) | p[1]; + BIO_printf(bp, "%X", v); + p += 2; + if (i == 7) { + BIO_puts(bp, "/"); + } else if (i != 15) { + BIO_puts(bp, ":"); + } + } + } else { + BIO_printf(bp, "IP Address:<invalid>"); + } + return 1; +} + +//- +// Check a certificate conforms to a specified set of constraints. +// Return values: +// X509_V_OK: All constraints obeyed. +// X509_V_ERR_PERMITTED_VIOLATION: Permitted subtree violation. +// X509_V_ERR_EXCLUDED_VIOLATION: Excluded subtree violation. +// X509_V_ERR_SUBTREE_MINMAX: Min or max values present and matching type. +// X509_V_ERR_UNSPECIFIED: Unspecified error. +// X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE: Unsupported constraint type. +// X509_V_ERR_UNSUPPORTED_CONSTRAINT_SYNTAX: Bad or unsupported constraint +// syntax. +// X509_V_ERR_UNSUPPORTED_NAME_SYNTAX: Bad or unsupported syntax of name. + +int NAME_CONSTRAINTS_check(X509 *x, NAME_CONSTRAINTS *nc) { + int r, i; + size_t j; + X509_NAME *nm; + + nm = X509_get_subject_name(x); + + // Guard against certificates with an excessive number of names or + // constraints causing a computationally expensive name constraints + // check. + size_t name_count = + X509_NAME_entry_count(nm) + sk_GENERAL_NAME_num(x->altname); + size_t constraint_count = sk_GENERAL_SUBTREE_num(nc->permittedSubtrees) + + sk_GENERAL_SUBTREE_num(nc->excludedSubtrees); + size_t check_count = constraint_count * name_count; + if (name_count < (size_t)X509_NAME_entry_count(nm) || + constraint_count < sk_GENERAL_SUBTREE_num(nc->permittedSubtrees) || + (constraint_count && check_count / constraint_count != name_count) || + check_count > 1 << 20) { + return X509_V_ERR_UNSPECIFIED; + } + + if (X509_NAME_entry_count(nm) > 0) { + GENERAL_NAME gntmp; + gntmp.type = GEN_DIRNAME; + gntmp.d.directoryName = nm; + + r = nc_match(&gntmp, nc); + + if (r != X509_V_OK) { + return r; + } + + gntmp.type = GEN_EMAIL; + + // Process any email address attributes in subject name + + for (i = -1;;) { + i = X509_NAME_get_index_by_NID(nm, NID_pkcs9_emailAddress, i); + if (i == -1) { + break; + } + const X509_NAME_ENTRY *ne = X509_NAME_get_entry(nm, i); + gntmp.d.rfc822Name = X509_NAME_ENTRY_get_data(ne); + if (gntmp.d.rfc822Name->type != V_ASN1_IA5STRING) { + return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX; + } + + r = nc_match(&gntmp, nc); + + if (r != X509_V_OK) { + return r; + } + } + } + + for (j = 0; j < sk_GENERAL_NAME_num(x->altname); j++) { + GENERAL_NAME *gen = sk_GENERAL_NAME_value(x->altname, j); + r = nc_match(gen, nc); + if (r != X509_V_OK) { + return r; + } + } + + return X509_V_OK; +} + +static int nc_match(GENERAL_NAME *gen, NAME_CONSTRAINTS *nc) { + GENERAL_SUBTREE *sub; + int r, match = 0; + size_t i; + + // Permitted subtrees: if any subtrees exist of matching the type at + // least one subtree must match. + + for (i = 0; i < sk_GENERAL_SUBTREE_num(nc->permittedSubtrees); i++) { + sub = sk_GENERAL_SUBTREE_value(nc->permittedSubtrees, i); + if (gen->type != sub->base->type) { + continue; + } + if (sub->minimum || sub->maximum) { + return X509_V_ERR_SUBTREE_MINMAX; + } + // If we already have a match don't bother trying any more + if (match == 2) { + continue; + } + if (match == 0) { + match = 1; + } + r = nc_match_single(gen, sub->base); + if (r == X509_V_OK) { + match = 2; + } else if (r != X509_V_ERR_PERMITTED_VIOLATION) { + return r; + } + } + + if (match == 1) { + return X509_V_ERR_PERMITTED_VIOLATION; + } + + // Excluded subtrees: must not match any of these + + for (i = 0; i < sk_GENERAL_SUBTREE_num(nc->excludedSubtrees); i++) { + sub = sk_GENERAL_SUBTREE_value(nc->excludedSubtrees, i); + if (gen->type != sub->base->type) { + continue; + } + if (sub->minimum || sub->maximum) { + return X509_V_ERR_SUBTREE_MINMAX; + } + + r = nc_match_single(gen, sub->base); + if (r == X509_V_OK) { + return X509_V_ERR_EXCLUDED_VIOLATION; + } else if (r != X509_V_ERR_PERMITTED_VIOLATION) { + return r; + } + } + + return X509_V_OK; +} + +static int nc_match_single(GENERAL_NAME *gen, GENERAL_NAME *base) { + switch (base->type) { + case GEN_DIRNAME: + return nc_dn(gen->d.directoryName, base->d.directoryName); + + case GEN_DNS: + return nc_dns(gen->d.dNSName, base->d.dNSName); + + case GEN_EMAIL: + return nc_email(gen->d.rfc822Name, base->d.rfc822Name); + + case GEN_URI: + return nc_uri(gen->d.uniformResourceIdentifier, + base->d.uniformResourceIdentifier); + + default: + return X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE; + } +} + +// directoryName name constraint matching. The canonical encoding of +// X509_NAME makes this comparison easy. It is matched if the subtree is a +// subset of the name. + +static int nc_dn(X509_NAME *nm, X509_NAME *base) { + // Ensure canonical encodings are up to date. + if (nm->modified && i2d_X509_NAME(nm, NULL) < 0) { + return X509_V_ERR_OUT_OF_MEM; + } + if (base->modified && i2d_X509_NAME(base, NULL) < 0) { + return X509_V_ERR_OUT_OF_MEM; + } + if (base->canon_enclen > nm->canon_enclen) { + return X509_V_ERR_PERMITTED_VIOLATION; + } + if (OPENSSL_memcmp(base->canon_enc, nm->canon_enc, base->canon_enclen)) { + return X509_V_ERR_PERMITTED_VIOLATION; + } + return X509_V_OK; +} + +static int starts_with(const CBS *cbs, uint8_t c) { + return CBS_len(cbs) > 0 && CBS_data(cbs)[0] == c; +} + +static int equal_case(const CBS *a, const CBS *b) { + if (CBS_len(a) != CBS_len(b)) { + return 0; + } + // Note we cannot use |OPENSSL_strncasecmp| because that would stop + // iterating at NUL. + const uint8_t *a_data = CBS_data(a), *b_data = CBS_data(b); + for (size_t i = 0; i < CBS_len(a); i++) { + if (OPENSSL_tolower(a_data[i]) != OPENSSL_tolower(b_data[i])) { + return 0; + } + } + return 1; +} + +static int has_suffix_case(const CBS *a, const CBS *b) { + if (CBS_len(a) < CBS_len(b)) { + return 0; + } + CBS copy = *a; + CBS_skip(©, CBS_len(a) - CBS_len(b)); + return equal_case(©, b); +} + +static int nc_dns(const ASN1_IA5STRING *dns, const ASN1_IA5STRING *base) { + CBS dns_cbs, base_cbs; + CBS_init(&dns_cbs, dns->data, dns->length); + CBS_init(&base_cbs, base->data, base->length); + + // Empty matches everything + if (CBS_len(&base_cbs) == 0) { + return X509_V_OK; + } + + // If |base_cbs| begins with a '.', do a simple suffix comparison. This is + // not part of RFC5280, but is part of OpenSSL's original behavior. + if (starts_with(&base_cbs, '.')) { + if (has_suffix_case(&dns_cbs, &base_cbs)) { + return X509_V_OK; + } + return X509_V_ERR_PERMITTED_VIOLATION; + } + + // Otherwise can add zero or more components on the left so compare RHS + // and if dns is longer and expect '.' as preceding character. + if (CBS_len(&dns_cbs) > CBS_len(&base_cbs)) { + uint8_t dot; + if (!CBS_skip(&dns_cbs, CBS_len(&dns_cbs) - CBS_len(&base_cbs) - 1) || + !CBS_get_u8(&dns_cbs, &dot) || dot != '.') { + return X509_V_ERR_PERMITTED_VIOLATION; + } + } + + if (!equal_case(&dns_cbs, &base_cbs)) { + return X509_V_ERR_PERMITTED_VIOLATION; + } + + return X509_V_OK; +} + +static int nc_email(const ASN1_IA5STRING *eml, const ASN1_IA5STRING *base) { + CBS eml_cbs, base_cbs; + CBS_init(&eml_cbs, eml->data, eml->length); + CBS_init(&base_cbs, base->data, base->length); + + // TODO(davidben): In OpenSSL 1.1.1, this switched from the first '@' to the + // last one. Match them here, or perhaps do an actual parse. Looks like + // multiple '@'s may be allowed in quoted strings. + CBS eml_local, base_local; + if (!CBS_get_until_first(&eml_cbs, &eml_local, '@')) { + return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX; + } + int base_has_at = CBS_get_until_first(&base_cbs, &base_local, '@'); + + // Special case: initial '.' is RHS match + if (!base_has_at && starts_with(&base_cbs, '.')) { + if (has_suffix_case(&eml_cbs, &base_cbs)) { + return X509_V_OK; + } + return X509_V_ERR_PERMITTED_VIOLATION; + } + + // If we have anything before '@' match local part + if (base_has_at) { + // TODO(davidben): This interprets a constraint of "@example.com" as + // "example.com", which is not part of RFC5280. + if (CBS_len(&base_local) > 0) { + // Case sensitive match of local part + if (!CBS_mem_equal(&base_local, CBS_data(&eml_local), + CBS_len(&eml_local))) { + return X509_V_ERR_PERMITTED_VIOLATION; + } + } + // Position base after '@' + assert(starts_with(&base_cbs, '@')); + CBS_skip(&base_cbs, 1); + } + + // Just have hostname left to match: case insensitive + assert(starts_with(&eml_cbs, '@')); + CBS_skip(&eml_cbs, 1); + if (!equal_case(&base_cbs, &eml_cbs)) { + return X509_V_ERR_PERMITTED_VIOLATION; + } + + return X509_V_OK; +} + +static int nc_uri(const ASN1_IA5STRING *uri, const ASN1_IA5STRING *base) { + CBS uri_cbs, base_cbs; + CBS_init(&uri_cbs, uri->data, uri->length); + CBS_init(&base_cbs, base->data, base->length); + + // Check for foo:// and skip past it + CBS scheme; + uint8_t byte; + if (!CBS_get_until_first(&uri_cbs, &scheme, ':') || + !CBS_skip(&uri_cbs, 1) || // Skip the colon + !CBS_get_u8(&uri_cbs, &byte) || byte != '/' || + !CBS_get_u8(&uri_cbs, &byte) || byte != '/') { + return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX; + } + + // Look for a port indicator as end of hostname first. Otherwise look for + // trailing slash, or the end of the string. + // TODO(davidben): This is not a correct URI parser and mishandles IPv6 + // literals. + CBS host; + if (!CBS_get_until_first(&uri_cbs, &host, ':') && + !CBS_get_until_first(&uri_cbs, &host, '/')) { + host = uri_cbs; + } + + if (CBS_len(&host) == 0) { + return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX; + } + + // Special case: initial '.' is RHS match + if (starts_with(&base_cbs, '.')) { + if (has_suffix_case(&host, &base_cbs)) { + return X509_V_OK; + } + return X509_V_ERR_PERMITTED_VIOLATION; + } + + if (!equal_case(&base_cbs, &host)) { + return X509_V_ERR_PERMITTED_VIOLATION; + } + + return X509_V_OK; +} |