DPP: Remove direct call to OpenSSL in dpp_test_gen_invalid_key()

Instead of generating EC point with random coordinates, generate a
valid EC point and then corrupt the coordinates after exporting them
in binary format.

Signed-off-by: Cedric Izoard <cedric.izoard@ceva-dsp.com>

diff --git a/src/common/dpp_crypto.c b/src/common/dpp_crypto.c
index 45e10518e8c53681d68afaa9b0ef1b756270c7b2..d110446a146650b427808435fb98b44675a0e8ed 100644 (file)
--- a/src/common/dpp_crypto.c
+++ b/src/common/dpp_crypto.c
@@ -297,20 +297,6 @@ int dpp_pbkdf2(size_t hash_len, const u8 *password, size_t password_len,
 #endif /* CONFIG_DPP2 */
 
 
-int dpp_bn2bin_pad(const BIGNUM *bn, u8 *pos, size_t len)
-{
-       int num_bytes, offset;
-
-       num_bytes = BN_num_bytes(bn);
-       if ((size_t) num_bytes > len)
-               return -1;
-       offset = len - num_bytes;
-       os_memset(pos, 0, offset);
-       BN_bn2bin(bn, pos + offset);
-       return 0;
-}
-
-
 struct crypto_ec_key * dpp_set_pubkey_point(struct crypto_ec_key *group_key,
                                            const u8 *buf, size_t len)
 {
@@ -2705,64 +2691,46 @@ fail:
 int dpp_test_gen_invalid_key(struct wpabuf *msg,
                             const struct dpp_curve_params *curve)
 {
-       BN_CTX *ctx;
-       BIGNUM *x, *y;
+       struct crypto_ec *ec;
+       struct crypto_ec_key *key = NULL;
+       const struct crypto_ec_point *pub_key;
+       struct crypto_ec_point *p = NULL;
+       u8 *x, *y;
        int ret = -1;
-       EC_GROUP *group;
-       EC_POINT *point;
-
-       group = EC_GROUP_new_by_curve_name(OBJ_txt2nid(curve->name));
-       if (!group)
-               return -1;
 
-       ctx = BN_CTX_new();
-       point = EC_POINT_new(group);
-       x = BN_new();
-       y = BN_new();
-       if (!ctx || !point || !x || !y)
+       ec = crypto_ec_init(curve->ike_group);
+       x = wpabuf_put(msg, curve->prime_len);
+       y = wpabuf_put(msg, curve->prime_len);
+       if (!ec)
                goto fail;
 
-       if (BN_rand(x, curve->prime_len * 8, 0, 0) != 1)
+retry:
+       /* Generate valid key pair */
+       key = crypto_ec_key_gen(curve->ike_group);
+       if (!key)
                goto fail;
 
-       /* Generate a random y coordinate that results in a point that is not
-        * on the curve. */
-       for (;;) {
-               if (BN_rand(y, curve->prime_len * 8, 0, 0) != 1)
-                       goto fail;
+       /* Retrieve public key coordinates */
+       pub_key = crypto_ec_key_get_public_key(key);
+       if (!pub_key)
+               goto fail;
 
-               if (EC_POINT_set_affine_coordinates_GFp(group, point, x, y,
-                                                       ctx) != 1) {
-#if OPENSSL_VERSION_NUMBER >= 0x10100000L || defined(OPENSSL_IS_BORINGSSL)
-               /* Unlike older OpenSSL versions, OpenSSL 1.1.1 and BoringSSL
-                * return an error from EC_POINT_set_affine_coordinates_GFp()
-                * when the point is not on the curve. */
-                       break;
-#else /* >=1.1.0 or OPENSSL_IS_BORINGSSL */
-                       goto fail;
-#endif /* >= 1.1.0 or OPENSSL_IS_BORINGSSL */
-               }
+       crypto_ec_point_to_bin(ec, pub_key, x, y);
 
-               if (!EC_POINT_is_on_curve(group, point, ctx))
-                       break;
+       /* And corrupt them */
+       y[curve->prime_len - 1] ^= 0x01;
+       p = crypto_ec_point_from_bin(ec, x);
+       if (p && crypto_ec_point_is_on_curve(ec, p)) {
+               crypto_ec_point_deinit(p, 0);
+               p = NULL;
+               goto retry;
        }
 
-       if (dpp_bn2bin_pad(x, wpabuf_put(msg, curve->prime_len),
-                          curve->prime_len) < 0 ||
-           dpp_bn2bin_pad(y, wpabuf_put(msg, curve->prime_len),
-                          curve->prime_len) < 0)
-               goto fail;
-
        ret = 0;
 fail:
-       if (ret < 0)
-               wpa_printf(MSG_INFO, "DPP: Failed to generate invalid key");
-       BN_free(x);
-       BN_free(y);
-       EC_POINT_free(point);
-       BN_CTX_free(ctx);
-       EC_GROUP_free(group);
-
+       crypto_ec_point_deinit(p, 0);
+       crypto_ec_key_deinit(key);
+       crypto_ec_deinit(ec);
        return ret;
 }
 

diff --git a/src/common/dpp_i.h b/src/common/dpp_i.h
index f63e5ae132a83858c0b78f7ced7630d4ae27aa5a..b5b4fca8f53b73fde2787158cfa422e81359473e 100644 (file)
--- a/src/common/dpp_i.h
+++ b/src/common/dpp_i.h
@@ -79,7 +79,6 @@ int dpp_bi_pubkey_hash(struct dpp_bootstrap_info *bi,
                       const u8 *data, size_t data_len);
 struct crypto_ec_key * dpp_set_pubkey_point(struct crypto_ec_key *group_key,
                                            const u8 *buf, size_t len);
-int dpp_bn2bin_pad(const BIGNUM *bn, u8 *pos, size_t len);
 int dpp_hkdf_expand(size_t hash_len, const u8 *secret, size_t secret_len,
                    const char *label, u8 *out, size_t outlen);
 int dpp_hmac_vector(size_t hash_len, const u8 *key, size_t key_len,