ref: 009439541d2c6e8af2596f8fb1b4df85861fd212
dir: /third_party/boringssl/src/crypto/x509/v3_purp.c/
/*
* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL project
* 2001.
*/
/* ====================================================================
* Copyright (c) 1999-2004 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 <string.h>
#include <openssl/digest.h>
#include <openssl/err.h>
#include <openssl/mem.h>
#include <openssl/obj.h>
#include <openssl/thread.h>
#include <openssl/x509.h>
#include "../internal.h"
#include "internal.h"
struct x509_purpose_st {
int purpose;
int trust; // Default trust ID
int (*check_purpose)(const struct x509_purpose_st *, const X509 *, int);
const char *sname;
} /* X509_PURPOSE */;
#define V1_ROOT (EXFLAG_V1 | EXFLAG_SS)
#define ku_reject(x, usage) \
(((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage)))
#define xku_reject(x, usage) \
(((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage)))
static int check_ca(const X509 *x);
static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x,
int ca);
static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x,
int ca);
static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x,
int ca);
static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x,
int ca);
static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x,
int ca);
static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x,
int ca);
static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x,
int ca);
static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca);
// X509_TRUST_NONE is not a valid |X509_TRUST_*| constant. It is used by
// |X509_PURPOSE_ANY| to indicate that it has no corresponding trust type and
// cannot be used with |X509_STORE_CTX_set_purpose|.
#define X509_TRUST_NONE (-1)
static const X509_PURPOSE xstandard[] = {
{X509_PURPOSE_SSL_CLIENT, X509_TRUST_SSL_CLIENT, check_purpose_ssl_client,
"sslclient"},
{X509_PURPOSE_SSL_SERVER, X509_TRUST_SSL_SERVER, check_purpose_ssl_server,
"sslserver"},
{X509_PURPOSE_NS_SSL_SERVER, X509_TRUST_SSL_SERVER,
check_purpose_ns_ssl_server, "nssslserver"},
{X509_PURPOSE_SMIME_SIGN, X509_TRUST_EMAIL, check_purpose_smime_sign,
"smimesign"},
{X509_PURPOSE_SMIME_ENCRYPT, X509_TRUST_EMAIL, check_purpose_smime_encrypt,
"smimeencrypt"},
{X509_PURPOSE_CRL_SIGN, X509_TRUST_COMPAT, check_purpose_crl_sign,
"crlsign"},
{X509_PURPOSE_ANY, X509_TRUST_NONE, no_check, "any"},
// |X509_PURPOSE_OCSP_HELPER| performs no actual checks. OpenSSL's OCSP
// implementation relied on the caller performing EKU and KU checks.
{X509_PURPOSE_OCSP_HELPER, X509_TRUST_COMPAT, no_check, "ocsphelper"},
{X509_PURPOSE_TIMESTAMP_SIGN, X509_TRUST_TSA, check_purpose_timestamp_sign,
"timestampsign"},
};
int X509_check_purpose(X509 *x, int id, int ca) {
// This differs from OpenSSL, which uses -1 to indicate a fatal error and 0 to
// indicate an invalid certificate. BoringSSL uses 0 for both.
if (!x509v3_cache_extensions(x)) {
return 0;
}
if (id == -1) {
return 1;
}
const X509_PURPOSE *pt = X509_PURPOSE_get0(id);
if (pt == NULL) {
return 0;
}
// Historically, |check_purpose| implementations other than |X509_PURPOSE_ANY|
// called |check_ca|. This is redundant with the |X509_V_ERR_INVALID_CA|
// logic, but |X509_check_purpose| is public API, so we preserve this
// behavior.
if (ca && id != X509_PURPOSE_ANY && !check_ca(x)) {
return 0;
}
return pt->check_purpose(pt, x, ca);
}
const X509_PURPOSE *X509_PURPOSE_get0(int id) {
for (size_t i = 0; i < OPENSSL_ARRAY_SIZE(xstandard); i++) {
if (xstandard[i].purpose == id) {
return &xstandard[i];
}
}
return NULL;
}
int X509_PURPOSE_get_by_sname(const char *sname) {
for (size_t i = 0; i < OPENSSL_ARRAY_SIZE(xstandard); i++) {
if (strcmp(xstandard[i].sname, sname) == 0) {
return xstandard[i].purpose;
}
}
return -1;
}
int X509_PURPOSE_get_id(const X509_PURPOSE *xp) { return xp->purpose; }
int X509_PURPOSE_get_trust(const X509_PURPOSE *xp) { return xp->trust; }
int X509_supported_extension(const X509_EXTENSION *ex) {
int nid = OBJ_obj2nid(X509_EXTENSION_get_object(ex));
return nid == NID_key_usage || //
nid == NID_subject_alt_name || //
nid == NID_basic_constraints || //
nid == NID_certificate_policies || //
nid == NID_ext_key_usage || //
nid == NID_policy_constraints || //
nid == NID_name_constraints || //
nid == NID_policy_mappings || //
nid == NID_inhibit_any_policy;
}
static int setup_dp(X509 *x, DIST_POINT *dp) {
if (!dp->distpoint || (dp->distpoint->type != 1)) {
return 1;
}
X509_NAME *iname = NULL;
for (size_t i = 0; i < sk_GENERAL_NAME_num(dp->CRLissuer); i++) {
GENERAL_NAME *gen = sk_GENERAL_NAME_value(dp->CRLissuer, i);
if (gen->type == GEN_DIRNAME) {
iname = gen->d.directoryName;
break;
}
}
if (!iname) {
iname = X509_get_issuer_name(x);
}
return DIST_POINT_set_dpname(dp->distpoint, iname);
}
static int setup_crldp(X509 *x) {
int j;
x->crldp = X509_get_ext_d2i(x, NID_crl_distribution_points, &j, NULL);
if (x->crldp == NULL && j != -1) {
return 0;
}
for (size_t i = 0; i < sk_DIST_POINT_num(x->crldp); i++) {
if (!setup_dp(x, sk_DIST_POINT_value(x->crldp, i))) {
return 0;
}
}
return 1;
}
int x509v3_cache_extensions(X509 *x) {
BASIC_CONSTRAINTS *bs;
ASN1_BIT_STRING *usage;
EXTENDED_KEY_USAGE *extusage;
size_t i;
int j;
CRYPTO_MUTEX_lock_read(&x->lock);
const int is_set = x->ex_flags & EXFLAG_SET;
CRYPTO_MUTEX_unlock_read(&x->lock);
if (is_set) {
return (x->ex_flags & EXFLAG_INVALID) == 0;
}
CRYPTO_MUTEX_lock_write(&x->lock);
if (x->ex_flags & EXFLAG_SET) {
CRYPTO_MUTEX_unlock_write(&x->lock);
return (x->ex_flags & EXFLAG_INVALID) == 0;
}
if (!X509_digest(x, EVP_sha256(), x->cert_hash, NULL)) {
x->ex_flags |= EXFLAG_INVALID;
}
// V1 should mean no extensions ...
if (X509_get_version(x) == X509_VERSION_1) {
x->ex_flags |= EXFLAG_V1;
}
// Handle basic constraints
if ((bs = X509_get_ext_d2i(x, NID_basic_constraints, &j, NULL))) {
if (bs->ca) {
x->ex_flags |= EXFLAG_CA;
}
if (bs->pathlen) {
if ((bs->pathlen->type == V_ASN1_NEG_INTEGER) || !bs->ca) {
x->ex_flags |= EXFLAG_INVALID;
x->ex_pathlen = 0;
} else {
// TODO(davidben): |ASN1_INTEGER_get| returns -1 on overflow,
// which currently acts as if the constraint isn't present. This
// works (an overflowing path length constraint may as well be
// infinity), but Chromium's verifier simply treats values above
// 255 as an error.
x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen);
}
} else {
x->ex_pathlen = -1;
}
BASIC_CONSTRAINTS_free(bs);
x->ex_flags |= EXFLAG_BCONS;
} else if (j != -1) {
x->ex_flags |= EXFLAG_INVALID;
}
// Handle key usage
if ((usage = X509_get_ext_d2i(x, NID_key_usage, &j, NULL))) {
if (usage->length > 0) {
x->ex_kusage = usage->data[0];
if (usage->length > 1) {
x->ex_kusage |= usage->data[1] << 8;
}
} else {
x->ex_kusage = 0;
}
x->ex_flags |= EXFLAG_KUSAGE;
ASN1_BIT_STRING_free(usage);
} else if (j != -1) {
x->ex_flags |= EXFLAG_INVALID;
}
x->ex_xkusage = 0;
if ((extusage = X509_get_ext_d2i(x, NID_ext_key_usage, &j, NULL))) {
x->ex_flags |= EXFLAG_XKUSAGE;
for (i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) {
switch (OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage, i))) {
case NID_server_auth:
x->ex_xkusage |= XKU_SSL_SERVER;
break;
case NID_client_auth:
x->ex_xkusage |= XKU_SSL_CLIENT;
break;
case NID_email_protect:
x->ex_xkusage |= XKU_SMIME;
break;
case NID_code_sign:
x->ex_xkusage |= XKU_CODE_SIGN;
break;
case NID_ms_sgc:
case NID_ns_sgc:
x->ex_xkusage |= XKU_SGC;
break;
case NID_OCSP_sign:
x->ex_xkusage |= XKU_OCSP_SIGN;
break;
case NID_time_stamp:
x->ex_xkusage |= XKU_TIMESTAMP;
break;
case NID_dvcs:
x->ex_xkusage |= XKU_DVCS;
break;
case NID_anyExtendedKeyUsage:
x->ex_xkusage |= XKU_ANYEKU;
break;
}
}
sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free);
} else if (j != -1) {
x->ex_flags |= EXFLAG_INVALID;
}
x->skid = X509_get_ext_d2i(x, NID_subject_key_identifier, &j, NULL);
if (x->skid == NULL && j != -1) {
x->ex_flags |= EXFLAG_INVALID;
}
x->akid = X509_get_ext_d2i(x, NID_authority_key_identifier, &j, NULL);
if (x->akid == NULL && j != -1) {
x->ex_flags |= EXFLAG_INVALID;
}
// Does subject name match issuer ?
if (!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x))) {
x->ex_flags |= EXFLAG_SI;
// If SKID matches AKID also indicate self signed
if (X509_check_akid(x, x->akid) == X509_V_OK &&
!ku_reject(x, X509v3_KU_KEY_CERT_SIGN)) {
x->ex_flags |= EXFLAG_SS;
}
}
x->altname = X509_get_ext_d2i(x, NID_subject_alt_name, &j, NULL);
if (x->altname == NULL && j != -1) {
x->ex_flags |= EXFLAG_INVALID;
}
x->nc = X509_get_ext_d2i(x, NID_name_constraints, &j, NULL);
if (x->nc == NULL && j != -1) {
x->ex_flags |= EXFLAG_INVALID;
}
if (!setup_crldp(x)) {
x->ex_flags |= EXFLAG_INVALID;
}
for (j = 0; j < X509_get_ext_count(x); j++) {
const X509_EXTENSION *ex = X509_get_ext(x, j);
if (!X509_EXTENSION_get_critical(ex)) {
continue;
}
if (!X509_supported_extension(ex)) {
x->ex_flags |= EXFLAG_CRITICAL;
break;
}
}
x->ex_flags |= EXFLAG_SET;
CRYPTO_MUTEX_unlock_write(&x->lock);
return (x->ex_flags & EXFLAG_INVALID) == 0;
}
// check_ca returns one if |x| should be considered a CA certificate and zero
// otherwise.
static int check_ca(const X509 *x) {
// keyUsage if present should allow cert signing
if (ku_reject(x, X509v3_KU_KEY_CERT_SIGN)) {
return 0;
}
// Version 1 certificates are considered CAs and don't have extensions.
if ((x->ex_flags & V1_ROOT) == V1_ROOT) {
return 1;
}
// Otherwise, it's only a CA if basicConstraints says so.
return ((x->ex_flags & EXFLAG_BCONS) && (x->ex_flags & EXFLAG_CA));
}
int X509_check_ca(X509 *x) {
if (!x509v3_cache_extensions(x)) {
return 0;
}
return check_ca(x);
}
// check_purpose returns one if |x| is a valid part of a certificate path for
// extended key usage |required_xku| and at least one of key usages in
// |required_kus|. |ca| indicates whether |x| is a CA or end-entity certificate.
static int check_purpose(const X509 *x, int ca, int required_xku,
int required_kus) {
// Check extended key usage on the entire chain.
if (required_xku != 0 && xku_reject(x, required_xku)) {
return 0;
}
// Check key usages only on the end-entity certificate.
return ca || !ku_reject(x, required_kus);
}
static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x,
int ca) {
// We need to do digital signatures or key agreement.
//
// TODO(davidben): We do not implement any TLS client certificate modes based
// on key agreement.
return check_purpose(x, ca, XKU_SSL_CLIENT,
X509v3_KU_DIGITAL_SIGNATURE | X509v3_KU_KEY_AGREEMENT);
}
// Key usage needed for TLS/SSL server: digital signature, encipherment or
// key agreement. The ssl code can check this more thoroughly for individual
// key types.
#define X509v3_KU_TLS \
(X509v3_KU_DIGITAL_SIGNATURE | X509v3_KU_KEY_ENCIPHERMENT | \
X509v3_KU_KEY_AGREEMENT)
static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x,
int ca) {
return check_purpose(x, ca, XKU_SSL_SERVER, X509v3_KU_TLS);
}
static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x,
int ca) {
// We need to encipher or Netscape complains.
return check_purpose(x, ca, XKU_SSL_SERVER, X509v3_KU_KEY_ENCIPHERMENT);
}
static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x,
int ca) {
return check_purpose(x, ca, XKU_SMIME,
X509v3_KU_DIGITAL_SIGNATURE | X509v3_KU_NON_REPUDIATION);
}
static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x,
int ca) {
return check_purpose(x, ca, XKU_SMIME, X509v3_KU_KEY_ENCIPHERMENT);
}
static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x,
int ca) {
return check_purpose(x, ca, /*required_xku=*/0, X509v3_KU_CRL_SIGN);
}
static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x,
int ca) {
if (ca) {
return 1;
}
// Check the optional key usage field:
// if Key Usage is present, it must be one of digitalSignature
// and/or nonRepudiation (other values are not consistent and shall
// be rejected).
if ((x->ex_flags & EXFLAG_KUSAGE) &&
((x->ex_kusage &
~(X509v3_KU_NON_REPUDIATION | X509v3_KU_DIGITAL_SIGNATURE)) ||
!(x->ex_kusage &
(X509v3_KU_NON_REPUDIATION | X509v3_KU_DIGITAL_SIGNATURE)))) {
return 0;
}
// Only time stamp key usage is permitted and it's required.
//
// TODO(davidben): Should we check EKUs up the chain like the other cases?
if (!(x->ex_flags & EXFLAG_XKUSAGE) || x->ex_xkusage != XKU_TIMESTAMP) {
return 0;
}
// Extended Key Usage MUST be critical
int i_ext = X509_get_ext_by_NID(x, NID_ext_key_usage, -1);
if (i_ext >= 0) {
const X509_EXTENSION *ext = X509_get_ext(x, i_ext);
if (!X509_EXTENSION_get_critical(ext)) {
return 0;
}
}
return 1;
}
static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca) { return 1; }
int X509_check_issued(X509 *issuer, X509 *subject) {
if (X509_NAME_cmp(X509_get_subject_name(issuer),
X509_get_issuer_name(subject))) {
return X509_V_ERR_SUBJECT_ISSUER_MISMATCH;
}
if (!x509v3_cache_extensions(issuer) || !x509v3_cache_extensions(subject)) {
return X509_V_ERR_UNSPECIFIED;
}
if (subject->akid) {
int ret = X509_check_akid(issuer, subject->akid);
if (ret != X509_V_OK) {
return ret;
}
}
if (ku_reject(issuer, X509v3_KU_KEY_CERT_SIGN)) {
return X509_V_ERR_KEYUSAGE_NO_CERTSIGN;
}
return X509_V_OK;
}
int X509_check_akid(X509 *issuer, const AUTHORITY_KEYID *akid) {
if (!akid) {
return X509_V_OK;
}
// Check key ids (if present)
if (akid->keyid && issuer->skid &&
ASN1_OCTET_STRING_cmp(akid->keyid, issuer->skid)) {
return X509_V_ERR_AKID_SKID_MISMATCH;
}
// Check serial number
if (akid->serial &&
ASN1_INTEGER_cmp(X509_get_serialNumber(issuer), akid->serial)) {
return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
}
// Check issuer name
if (akid->issuer) {
// Ugh, for some peculiar reason AKID includes SEQUENCE OF
// GeneralName. So look for a DirName. There may be more than one but
// we only take any notice of the first.
GENERAL_NAMES *gens;
GENERAL_NAME *gen;
X509_NAME *nm = NULL;
size_t i;
gens = akid->issuer;
for (i = 0; i < sk_GENERAL_NAME_num(gens); i++) {
gen = sk_GENERAL_NAME_value(gens, i);
if (gen->type == GEN_DIRNAME) {
nm = gen->d.dirn;
break;
}
}
if (nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer))) {
return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
}
}
return X509_V_OK;
}
uint32_t X509_get_extension_flags(X509 *x) {
// Ignore the return value. On failure, |x->ex_flags| will include
// |EXFLAG_INVALID|.
x509v3_cache_extensions(x);
return x->ex_flags;
}
uint32_t X509_get_key_usage(X509 *x) {
if (!x509v3_cache_extensions(x)) {
return 0;
}
if (x->ex_flags & EXFLAG_KUSAGE) {
return x->ex_kusage;
}
// If there is no extension, key usage is unconstrained, so set all bits to
// one. Note that, although we use |UINT32_MAX|, |ex_kusage| only contains the
// first 16 bits when the extension is present.
return UINT32_MAX;
}
uint32_t X509_get_extended_key_usage(X509 *x) {
if (!x509v3_cache_extensions(x)) {
return 0;
}
if (x->ex_flags & EXFLAG_XKUSAGE) {
return x->ex_xkusage;
}
// If there is no extension, extended key usage is unconstrained, so set all
// bits to one.
return UINT32_MAX;
}
const ASN1_OCTET_STRING *X509_get0_subject_key_id(X509 *x509) {
if (!x509v3_cache_extensions(x509)) {
return NULL;
}
return x509->skid;
}
const ASN1_OCTET_STRING *X509_get0_authority_key_id(X509 *x509) {
if (!x509v3_cache_extensions(x509)) {
return NULL;
}
return x509->akid != NULL ? x509->akid->keyid : NULL;
}
const GENERAL_NAMES *X509_get0_authority_issuer(X509 *x509) {
if (!x509v3_cache_extensions(x509)) {
return NULL;
}
return x509->akid != NULL ? x509->akid->issuer : NULL;
}
const ASN1_INTEGER *X509_get0_authority_serial(X509 *x509) {
if (!x509v3_cache_extensions(x509)) {
return NULL;
}
return x509->akid != NULL ? x509->akid->serial : NULL;
}
long X509_get_pathlen(X509 *x509) {
if (!x509v3_cache_extensions(x509) || (x509->ex_flags & EXFLAG_BCONS) == 0) {
return -1;
}
return x509->ex_pathlen;
}