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DPP: Replace dpp_bootstrap_key_der() with crypto_ec_key_get_subject_public_key()

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As BoringSSL version of i2d_PUBKEY() doesn't respect the
POINT_CONVERSION_COMPRESSED flag redefine a specific
crypto_ec_key_get_subject_public_key() version for BoringSSL based on
dpp_bootstrap_key_der().

The only other user of crypto_ec_key_get_subject_public_key() is SAE-PK
for which the public key should also be formatted using compressed
format.

Signed-off-by: Cedric Izoard <cedric.izoard@ceva-dsp.com>
This commit is contained in:
Cedric Izoard 2021-10-29 11:05:32 +02:00 committed by Jouni Malinen
parent e9f8f81a82
commit 2086ae46b3
4 changed files with 98 additions and 90 deletions
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2
src/common/dpp.c
View file

@ -8,8 +8,6 @@
*/
#include "utils/includes.h"
#include <openssl/evp.h>
#include <openssl/x509.h>
#include "utils/common.h"
#include "utils/base64.h"

89
src/common/dpp_crypto.c
View file

@ -8,10 +8,6 @@
*/
#include "utils/includes.h"
#include <openssl/err.h>
#include <openssl/asn1.h>
#include <openssl/asn1t.h>
#include <openssl/pem.h>
#include "utils/common.h"
#include "utils/base64.h"
@ -295,93 +291,12 @@ struct crypto_ec_key * dpp_set_keypair(const struct dpp_curve_params **curve,
}
typedef struct {
/* AlgorithmIdentifier ecPublicKey with optional parameters present
* as an OID identifying the curve */
X509_ALGOR *alg;
/* Compressed format public key per ANSI X9.63 */
ASN1_BIT_STRING *pub_key;
} DPP_BOOTSTRAPPING_KEY;
ASN1_SEQUENCE(DPP_BOOTSTRAPPING_KEY) = {
ASN1_SIMPLE(DPP_BOOTSTRAPPING_KEY, alg, X509_ALGOR),
ASN1_SIMPLE(DPP_BOOTSTRAPPING_KEY, pub_key, ASN1_BIT_STRING)
} ASN1_SEQUENCE_END(DPP_BOOTSTRAPPING_KEY);
IMPLEMENT_ASN1_FUNCTIONS(DPP_BOOTSTRAPPING_KEY);
static struct wpabuf * dpp_bootstrap_key_der(struct crypto_ec_key *key)
{
unsigned char *der = NULL;
int der_len;
const EC_KEY *eckey;
struct wpabuf *ret = NULL;
size_t len;
const EC_GROUP *group;
const EC_POINT *point;
BN_CTX *ctx;
DPP_BOOTSTRAPPING_KEY *bootstrap = NULL;
int nid;
ctx = BN_CTX_new();
eckey = EVP_PKEY_get0_EC_KEY((EVP_PKEY *) key);
if (!ctx || !eckey)
goto fail;
group = EC_KEY_get0_group(eckey);
point = EC_KEY_get0_public_key(eckey);
if (!group || !point)
goto fail;
nid = EC_GROUP_get_curve_name(group);
bootstrap = DPP_BOOTSTRAPPING_KEY_new();
if (!bootstrap ||
X509_ALGOR_set0(bootstrap->alg, OBJ_nid2obj(EVP_PKEY_EC),
V_ASN1_OBJECT, (void *) OBJ_nid2obj(nid)) != 1)
goto fail;
len = EC_POINT_point2oct(group, point, POINT_CONVERSION_COMPRESSED,
NULL, 0, ctx);
if (len == 0)
goto fail;
der = OPENSSL_malloc(len);
if (!der)
goto fail;
len = EC_POINT_point2oct(group, point, POINT_CONVERSION_COMPRESSED,
der, len, ctx);
OPENSSL_free(bootstrap->pub_key->data);
bootstrap->pub_key->data = der;
der = NULL;
bootstrap->pub_key->length = len;
/* No unused bits */
bootstrap->pub_key->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07);
bootstrap->pub_key->flags |= ASN1_STRING_FLAG_BITS_LEFT;
der_len = i2d_DPP_BOOTSTRAPPING_KEY(bootstrap, &der);
if (der_len <= 0) {
wpa_printf(MSG_ERROR,
"DDP: Failed to build DER encoded public key");
goto fail;
}
ret = wpabuf_alloc_copy(der, der_len);
fail:
DPP_BOOTSTRAPPING_KEY_free(bootstrap);
OPENSSL_free(der);
BN_CTX_free(ctx);
return ret;
}
int dpp_bootstrap_key_hash(struct dpp_bootstrap_info *bi)
{
struct wpabuf *der;
int res;
der = dpp_bootstrap_key_der(bi->pubkey);
der = crypto_ec_key_get_subject_public_key(bi->pubkey);
if (!der)
return -1;
wpa_hexdump_buf(MSG_DEBUG, "DPP: Compressed public key (DER)",
@ -416,7 +331,7 @@ int dpp_keygen(struct dpp_bootstrap_info *bi, const char *curve,
goto fail;
bi->own = 1;
der = dpp_bootstrap_key_der(bi->pubkey);
der = crypto_ec_key_get_subject_public_key(bi->pubkey);
if (!der)
goto fail;
wpa_hexdump_buf(MSG_DEBUG, "DPP: Compressed public key (DER)",

94
src/crypto/crypto_openssl.c
View file

@ -2501,12 +2501,105 @@ void crypto_ec_key_deinit(struct crypto_ec_key *key)
}
#ifdef OPENSSL_IS_BORINGSSL
/* BoringSSL version of i2d_PUBKEY() always outputs public EC key using
* uncompressed form so define a custom function to export EC pubkey using
* the compressed format that is explicitly required for some protocols. */
#include <openssl/asn1.h>
#include <openssl/asn1t.h>
typedef struct {
/* AlgorithmIdentifier ecPublicKey with optional parameters present
* as an OID identifying the curve */
X509_ALGOR *alg;
/* Compressed format public key per ANSI X9.63 */
ASN1_BIT_STRING *pub_key;
} EC_COMP_PUBKEY;
ASN1_SEQUENCE(EC_COMP_PUBKEY) = {
ASN1_SIMPLE(EC_COMP_PUBKEY, alg, X509_ALGOR),
ASN1_SIMPLE(EC_COMP_PUBKEY, pub_key, ASN1_BIT_STRING)
} ASN1_SEQUENCE_END(EC_COMP_PUBKEY);
IMPLEMENT_ASN1_FUNCTIONS(EC_COMP_PUBKEY);
#endif /* OPENSSL_IS_BORINGSSL */
struct wpabuf * crypto_ec_key_get_subject_public_key(struct crypto_ec_key *key)
{
#ifdef OPENSSL_IS_BORINGSSL
unsigned char *der = NULL;
int der_len;
const EC_KEY *eckey;
struct wpabuf *ret = NULL;
size_t len;
const EC_GROUP *group;
const EC_POINT *point;
BN_CTX *ctx;
EC_COMP_PUBKEY *pubkey = NULL;
int nid;
ctx = BN_CTX_new();
eckey = EVP_PKEY_get0_EC_KEY((EVP_PKEY *) key);
if (!ctx || !eckey)
goto fail;
group = EC_KEY_get0_group(eckey);
point = EC_KEY_get0_public_key(eckey);
if (!group || !point)
goto fail;
nid = EC_GROUP_get_curve_name(group);
pubkey = EC_COMP_PUBKEY_new();
if (!pubkey ||
X509_ALGOR_set0(pubkey->alg, OBJ_nid2obj(EVP_PKEY_EC),
V_ASN1_OBJECT, (void *) OBJ_nid2obj(nid)) != 1)
goto fail;
len = EC_POINT_point2oct(group, point, POINT_CONVERSION_COMPRESSED,
NULL, 0, ctx);
if (len == 0)
goto fail;
der = OPENSSL_malloc(len);
if (!der)
goto fail;
len = EC_POINT_point2oct(group, point, POINT_CONVERSION_COMPRESSED,
der, len, ctx);
OPENSSL_free(pubkey->pub_key->data);
pubkey->pub_key->data = der;
der = NULL;
pubkey->pub_key->length = len;
/* No unused bits */
pubkey->pub_key->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07);
pubkey->pub_key->flags |= ASN1_STRING_FLAG_BITS_LEFT;
der_len = i2d_EC_COMP_PUBKEY(pubkey, &der);
if (der_len <= 0) {
wpa_printf(MSG_ERROR,
"BoringSSL: Failed to build DER encoded public key");
goto fail;
}
ret = wpabuf_alloc_copy(der, der_len);
fail:
EC_COMP_PUBKEY_free(pubkey);
OPENSSL_free(der);
BN_CTX_free(ctx);
return ret;
#else /* OPENSSL_IS_BORINGSSL */
unsigned char *der = NULL;
int der_len;
struct wpabuf *buf;
/* For now, all users expect COMPRESSED form */
EC_KEY_set_conv_form(EVP_PKEY_get0_EC_KEY((EVP_PKEY *) key),
POINT_CONVERSION_COMPRESSED);
der_len = i2d_PUBKEY((EVP_PKEY *) key, &der);
if (der_len <= 0) {
wpa_printf(MSG_INFO, "OpenSSL: i2d_PUBKEY() failed: %s",
@ -2517,6 +2610,7 @@ struct wpabuf * crypto_ec_key_get_subject_public_key(struct crypto_ec_key *key)
buf = wpabuf_alloc_copy(der, der_len);
OPENSSL_free(der);
return buf;
#endif /* OPENSSL_IS_BORINGSSL */
}

3
tests/hwsim/test_dpp.py
View file

@ -214,7 +214,8 @@ def test_dpp_qr_code_keygen_fail(dev, apdev):
"""DPP QR Code and keygen failure"""
check_dpp_capab(dev[0])
with alloc_fail(dev[0], 1, "dpp_bootstrap_key_der;dpp_keygen"):
with alloc_fail(dev[0], 1,
"crypto_ec_key_get_subject_public_key;dpp_keygen"):
if "FAIL" not in dev[0].request("DPP_BOOTSTRAP_GEN type=qrcode"):
raise Exception("Failure not reported")