/*
* Copyright 2003-2018 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include "internal/cryptlib.h"
#include "internal/numbers.h"
#include <stdio.h>
#include "crypto/asn1.h"
#include <openssl/asn1t.h>
#include <openssl/conf.h>
#include <openssl/x509v3.h>
#include "crypto/x509.h"
#include "ext_dat.h"
static void *v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method,
X509V3_CTX *ctx,
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, 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(ASN1_IA5STRING *sub, ASN1_IA5STRING *dns);
static int nc_email(ASN1_IA5STRING *sub, ASN1_IA5STRING *eml);
static int nc_uri(ASN1_IA5STRING *uri, ASN1_IA5STRING *base);
static int nc_ip(ASN1_OCTET_STRING *ip, ASN1_OCTET_STRING *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)
/*
* We cannot use strncasecmp here because that applies locale specific rules.
* For example in Turkish 'I' is not the uppercase character for 'i'. We need to
* do a simple ASCII case comparison ignoring the locale (that is why we use
* numeric constants below).
*/
static int ia5ncasecmp(const char *s1, const char *s2, size_t n)
{
for (; n > 0; n--, s1++, s2++) {
if (*s1 != *s2) {
unsigned char c1 = (unsigned char)*s1, c2 = (unsigned char)*s2;
/* Convert to lower case */
if (c1 >= 0x41 /* A */ && c1 <= 0x5A /* Z */)
c1 += 0x20;
if (c2 >= 0x41 /* A */ && c2 <= 0x5A /* Z */)
c2 += 0x20;
if (c1 == c2)
continue;
if (c1 < c2)
return -1;
/* c1 > c2 */
return 1;
} else if (*s1 == 0) {
/* If we get here we know that *s2 == 0 too */
return 0;
}
}
return 0;
}
static int ia5casecmp(const char *s1, const char *s2)
{
return ia5ncasecmp(s1, s2, SIZE_MAX);
}
static void *v2i_NAME_CONSTRAINTS(const X509V3_EXT_METHOD *method,
X509V3_CTX *ctx, STACK_OF(CONF_VALUE) *nval)
{
int i;
CONF_VALUE tval, *val;
STACK_OF(GENERAL_SUBTREE) **ptree = NULL;
NAME_CONSTRAINTS *ncons = NULL;
GENERAL_SUBTREE *sub = NULL;
ncons = NAME_CONSTRAINTS_new();
if (ncons == NULL)
goto memerr;
for (i = 0; i < sk_CONF_VALUE_num(nval); i++) {
val = sk_CONF_VALUE_value(nval, i);
if (strncmp(val->name, "permitted", 9) == 0 && val->name[9]) {
ptree = &ncons->permittedSubtrees;
tval.name = val->name + 10;
} else if (strncmp(val->name, "excluded", 8) == 0 && val->name[8]) {
ptree = &ncons->excludedSubtrees;
tval.name = val->name + 9;
} else {
X509V3err(X509V3_F_V2I_NAME_CONSTRAINTS, X509V3_R_INVALID_SYNTAX);
goto err;
}
tval.value = val->value;
sub = GENERAL_SUBTREE_new();
if (sub == NULL)
goto memerr;
if (!v2i_GENERAL_NAME_ex(sub->base, method, ctx, &tval, 1))
goto err;
if (*ptree == NULL)
*ptree = sk_GENERAL_SUBTREE_new_null();
if (*ptree == NULL || !sk_GENERAL_SUBTREE_push(*ptree, sub))
goto memerr;
sub = NULL;
}
return ncons;
memerr:
X509V3err(X509V3_F_V2I_NAME_CONSTRAINTS, ERR_R_MALLOC_FAILURE);
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;
int 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, 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++) {
BIO_printf(bp, "%X", p[0] << 8 | p[1]);
p += 2;
if (i == 7)
BIO_puts(bp, "/");
else if (i != 15)
BIO_puts(bp, ":");
}
} else
BIO_printf(bp, "IP Address:<invalid>");
return 1;
}
#define NAME_CHECK_MAX (1 << 20)
static int add_lengths(int *out, int a, int b)
{
/* sk_FOO_num(NULL) returns -1 but is effectively 0 when iterating. */
if (a < 0)
a = 0;
if (b < 0)
b = 0;
if (a > INT_MAX - b)
return 0;
*out = a + b;
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_UNSUPPORTED_CONSTRAINT_TYPE: Unsupported constraint type.
* X509_V_ERR_UNSUPPORTED_CONSTRAINT_SYNTAX: bad 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, name_count, constraint_count;
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.
*/
if (!add_lengths(&name_count, X509_NAME_entry_count(nm),
sk_GENERAL_NAME_num(x->altname))
|| !add_lengths(&constraint_count,
sk_GENERAL_SUBTREE_num(nc->permittedSubtrees),
sk_GENERAL_SUBTREE_num(nc->excludedSubtrees))
|| (name_count > 0 && constraint_count > NAME_CHECK_MAX / name_count))
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;;) {
const X509_NAME_ENTRY *ne;
i = X509_NAME_get_index_by_NID(nm, NID_pkcs9_emailAddress, i);
if (i == -1)
break;
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 (i = 0; i < sk_GENERAL_NAME_num(x->altname); i++) {
GENERAL_NAME *gen = sk_GENERAL_NAME_value(x->altname, i);
r = nc_match(gen, nc);
if (r != X509_V_OK)
return r;
}
return X509_V_OK;
}
static int cn2dnsid(ASN1_STRING *cn, unsigned char **dnsid, size_t *idlen)
{
int utf8_length;
unsigned char *utf8_value;
int i;
int isdnsname = 0;
/* Don't leave outputs uninitialized */
*dnsid = NULL;
*idlen = 0;
/*-
* Per RFC 6125, DNS-IDs representing internationalized domain names appear
* in certificates in A-label encoded form:
*
* https://tools.ietf.org/html/rfc6125#section-6.4.2
*
* The same applies to CNs which are intended to represent DNS names.
* However, while in the SAN DNS-IDs are IA5Strings, as CNs they may be
* needlessly encoded in 16-bit Unicode. We perform a conversion to UTF-8
* to ensure that we get an ASCII representation of any CNs that are
* representable as ASCII, but just not encoded as ASCII. The UTF-8 form
* may contain some non-ASCII octets, and that's fine, such CNs are not
* valid legacy DNS names.
*
* Note, 'int' is the return type of ASN1_STRING_to_UTF8() so that's what
* we must use for 'utf8_length'.
*/
if ((utf8_length = ASN1_STRING_to_UTF8(&utf8_value, cn)) < 0)
return X509_V_ERR_OUT_OF_MEM;
/*
* Some certificates have had names that include a *trailing* NUL byte.
* Remove these harmless NUL characters. They would otherwise yield false
* alarms with the following embedded NUL check.
*/
while (utf8_length > 0 && utf8_value[utf8_length - 1] == '\0')
--utf8_length;
/* Reject *embedded* NULs */
if ((size_t)utf8_length != strlen((char *)utf8_value)) {
OPENSSL_free(utf8_value);
return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
}
/*
* XXX: Deviation from strict DNS name syntax, also check names with '_'
* Check DNS name syntax, any '-' or '.' must be internal,
* and on either side of each '.' we can't have a '-' or '.'.
*
* If the name has just one label, we don't consider it a DNS name. This
* means that "CN=sometld" cannot be precluded by DNS name constraints, but
* that is not a problem.
*/
for (i = 0; i < utf8_length; ++i) {
unsigned char c = utf8_value[i];
if ((c >= 'a' && c <= 'z')
|| (c >= 'A' && c <= 'Z')
|| (c >= '0' && c <= '9')
|| c == '_')
continue;
/* Dot and hyphen cannot be first or last. */
if (i > 0 && i < utf8_length - 1) {
if (c == '-')
continue;
/*
* Next to a dot the preceding and following characters must not be
* another dot or a hyphen. Otherwise, record that the name is
* plausible, since it has two or more labels.
*/
if (c == '.'
&& utf8_value[i + 1] != '.'
&& utf8_value[i - 1] != '-'
&& utf8_value[i + 1] != '-') {
isdnsname = 1;
continue;
}
}
isdnsname = 0;
break;
}
if (isdnsname) {
*dnsid = utf8_value;
*idlen = (size_t)utf8_length;
return X509_V_OK;
}
OPENSSL_free(utf8_value);
return X509_V_OK;
}
/*
* Check CN against DNS-ID name constraints.
*/
int NAME_CONSTRAINTS_check_CN(X509 *x, NAME_CONSTRAINTS *nc)
{
int r, i;
X509_NAME *nm = X509_get_subject_name(x);
ASN1_STRING stmp;
GENERAL_NAME gntmp;
stmp.flags = 0;
stmp.type = V_ASN1_IA5STRING;
gntmp.type = GEN_DNS;
gntmp.d.dNSName = &stmp;
/* Process any commonName attributes in subject name */
for (i = -1;;) {
X509_NAME_ENTRY *ne;
ASN1_STRING *cn;
unsigned char *idval;
size_t idlen;
i = X509_NAME_get_index_by_NID(nm, NID_commonName, i);
if (i == -1)
break;
ne = X509_NAME_get_entry(nm, i);
cn = X509_NAME_ENTRY_get_data(ne);
/* Only process attributes that look like host names */
if ((r = cn2dnsid(cn, &idval, &idlen)) != X509_V_OK)
return r;
if (idlen == 0)
continue;
stmp.length = idlen;
stmp.data = idval;
r = nc_match(&gntmp, nc);
OPENSSL_free(idval);
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 i, r, match = 0;
/*
* 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);
case GEN_IPADD:
return nc_ip(gen->d.iPAddress, base->d.iPAddress);
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 (memcmp(base->canon_enc, nm->canon_enc, base->canon_enclen))
return X509_V_ERR_PERMITTED_VIOLATION;
return X509_V_OK;
}
static int nc_dns(ASN1_IA5STRING *dns, ASN1_IA5STRING *base)
{
char *baseptr = (char *)base->data;
char *dnsptr = (char *)dns->data;
/* Empty matches everything */
if (!*baseptr)
return X509_V_OK;
/*
* Otherwise can add zero or more components on the left so compare RHS
* and if dns is longer and expect '.' as preceding character.
*/
if (dns->length > base->length) {
dnsptr += dns->length - base->length;
if (*baseptr != '.' && dnsptr[-1] != '.')
return X509_V_ERR_PERMITTED_VIOLATION;
}
if (ia5casecmp(baseptr, dnsptr))
return X509_V_ERR_PERMITTED_VIOLATION;
return X509_V_OK;
}
static int nc_email(ASN1_IA5STRING *eml, ASN1_IA5STRING *base)
{
const char *baseptr = (char *)base->data;
const char *emlptr = (char *)eml->data;
const char *baseat = strchr(baseptr, '@');
const char *emlat = strchr(emlptr, '@');
if (!emlat)
return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
/* Special case: initial '.' is RHS match */
if (!baseat && (*baseptr == '.')) {
if (eml->length > base->length) {
emlptr += eml->length - base->length;
if (ia5casecmp(baseptr, emlptr) == 0)
return X509_V_OK;
}
return X509_V_ERR_PERMITTED_VIOLATION;
}
/* If we have anything before '@' match local part */
if (baseat) {
if (baseat != baseptr) {
if ((baseat - baseptr) != (emlat - emlptr))
return X509_V_ERR_PERMITTED_VIOLATION;
/* Case sensitive match of local part */
if (strncmp(baseptr, emlptr, emlat - emlptr))
return X509_V_ERR_PERMITTED_VIOLATION;
}
/* Position base after '@' */
baseptr = baseat + 1;
}
emlptr = emlat + 1;
/* Just have hostname left to match: case insensitive */
if (ia5casecmp(baseptr, emlptr))
return X509_V_ERR_PERMITTED_VIOLATION;
return X509_V_OK;
}
static int nc_uri(ASN1_IA5STRING *uri, ASN1_IA5STRING *base)
{
const char *baseptr = (char *)base->data;
const char *hostptr = (char *)uri->data;
const char *p = strchr(hostptr, ':');
int hostlen;
/* Check for foo:// and skip past it */
if (!p || (p[1] != '/') || (p[2] != '/'))
return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
hostptr = p + 3;
/* Determine length of hostname part of URI */
/* Look for a port indicator as end of hostname first */
p = strchr(hostptr, ':');
/* Otherwise look for trailing slash */
if (!p)
p = strchr(hostptr, '/');
if (!p)
hostlen = strlen(hostptr);
else
hostlen = p - hostptr;
if (hostlen == 0)
return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
/* Special case: initial '.' is RHS match */
if (*baseptr == '.') {
if (hostlen > base->length) {
p = hostptr + hostlen - base->length;
if (ia5ncasecmp(p, baseptr, base->length) == 0)
return X509_V_OK;
}
return X509_V_ERR_PERMITTED_VIOLATION;
}
if ((base->length != (int)hostlen)
|| ia5ncasecmp(hostptr, baseptr, hostlen))
return X509_V_ERR_PERMITTED_VIOLATION;
return X509_V_OK;
}
static int nc_ip(ASN1_OCTET_STRING *ip, ASN1_OCTET_STRING *base)
{
int hostlen, baselen, i;
unsigned char *hostptr, *baseptr, *maskptr;
hostptr = ip->data;
hostlen = ip->length;
baseptr = base->data;
baselen = base->length;
/* Invalid if not IPv4 or IPv6 */
if (!((hostlen == 4) || (hostlen == 16)))
return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
if (!((baselen == 8) || (baselen == 32)))
return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
/* Do not match IPv4 with IPv6 */
if (hostlen * 2 != baselen)
return X509_V_ERR_PERMITTED_VIOLATION;
maskptr = base->data + hostlen;
/* Considering possible not aligned base ipAddress */
/* Not checking for wrong mask definition: i.e.: 255.0.255.0 */
for (i = 0; i < hostlen; i++)
if ((hostptr[i] & maskptr[i]) != (baseptr[i] & maskptr[i]))
return X509_V_ERR_PERMITTED_VIOLATION;
return X509_V_OK;
}