DPP: Add helper functions for running hash operations

Use helper functions to cover all three different hash algorithm options
for DPP operations instead of having separate calls to each function at
every location a hash operation based on the curve is needed.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>

src/common/dpp.c

@@ -61,6 +61,69 @@ static const struct dpp_curve_params dpp_curves[] = {
 };
 
 
+static int dpp_hash_vector(const struct dpp_curve_params *curve,
+			   size_t num_elem, const u8 *addr[], const size_t *len,
+			   u8 *mac)
+{
+	if (curve->hash_len == 32)
+		return sha256_vector(num_elem, addr, len, mac);
+	if (curve->hash_len == 48)
+		return sha384_vector(num_elem, addr, len, mac);
+	if (curve->hash_len == 64)
+		return sha512_vector(num_elem, addr, len, mac);
+	return -1;
+}
+
+
+static int dpp_hkdf_expand(size_t hash_len, const u8 *secret, size_t secret_len,
+			   const char *label, u8 *out, size_t outlen)
+{
+	if (hash_len == 32)
+		return hmac_sha256_kdf(secret, secret_len, NULL,
+				       (const u8 *) label, os_strlen(label),
+				       out, outlen);
+	if (hash_len == 48)
+		return hmac_sha384_kdf(secret, secret_len, NULL,
+				       (const u8 *) label, os_strlen(label),
+				       out, outlen);
+	if (hash_len == 64)
+		return hmac_sha512_kdf(secret, secret_len, NULL,
+				       (const u8 *) label, os_strlen(label),
+				       out, outlen);
+	return -1;
+}
+
+
+static int dpp_hmac_vector(size_t hash_len, const u8 *key, size_t key_len,
+			   size_t num_elem, const u8 *addr[],
+			   const size_t *len, u8 *mac)
+{
+	if (hash_len == 32)
+		return hmac_sha256_vector(key, key_len, num_elem, addr, len,
+					  mac);
+	if (hash_len == 48)
+		return hmac_sha384_vector(key, key_len, num_elem, addr, len,
+					  mac);
+	if (hash_len == 64)
+		return hmac_sha512_vector(key, key_len, num_elem, addr, len,
+					  mac);
+	return -1;
+}
+
+
+static int dpp_hmac(size_t hash_len, const u8 *key, size_t key_len,
+		    const u8 *data, size_t data_len, u8 *mac)
+{
+	if (hash_len == 32)
+		return hmac_sha256(key, key_len, data, data_len, mac);
+	if (hash_len == 48)
+		return hmac_sha384(key, key_len, data, data_len, mac);
+	if (hash_len == 64)
+		return hmac_sha512(key, key_len, data, data_len, mac);
+	return -1;
+}
+
+
 static struct wpabuf * dpp_get_pubkey_point(EVP_PKEY *pkey, int prefix)
 {
 	int len, res;
@@ -903,40 +966,19 @@ static int dpp_derive_k1(const u8 *Mx, size_t Mx_len, u8 *k1,
 {
 	u8 salt[DPP_MAX_HASH_LEN], prk[DPP_MAX_HASH_LEN];
 	const char *info = "first intermediate key";
-	int res = -1;
+	int res;
 
 	/* k1 = HKDF(<>, "first intermediate key", M.x) */
 
 	/* HKDF-Extract(<>, M.x) */
 	os_memset(salt, 0, hash_len);
-	if (hash_len == 32) {
-		if (hmac_sha256(salt, SHA256_MAC_LEN, Mx, Mx_len, prk) < 0)
-			return -1;
-	} else if (hash_len == 48) {
-		if (hmac_sha384(salt, SHA384_MAC_LEN, Mx, Mx_len, prk) < 0)
-			return -1;
-	} else if (hash_len == 64) {
-		if (hmac_sha512(salt, SHA512_MAC_LEN, Mx, Mx_len, prk) < 0)
-			return -1;
-	} else {
+	if (dpp_hmac(hash_len, salt, hash_len, Mx, Mx_len, prk) < 0)
 		return -1;
-	}
 	wpa_hexdump_key(MSG_DEBUG, "DPP: PRK = HKDF-Extract(<>, IKM=M.x)",
 			prk, hash_len);
 
 	/* HKDF-Expand(PRK, info, L) */
-	if (hash_len == 32)
-		res = hmac_sha256_kdf(prk, SHA256_MAC_LEN, NULL,
-				      (const u8 *) info, os_strlen(info),
-				      k1, SHA256_MAC_LEN);
-	else if (hash_len == 48)
-		res = hmac_sha384_kdf(prk, SHA384_MAC_LEN, NULL,
-				      (const u8 *) info, os_strlen(info),
-				      k1, SHA384_MAC_LEN);
-	else if (hash_len == 64)
-		res = hmac_sha512_kdf(prk, SHA512_MAC_LEN, NULL,
-				      (const u8 *) info, os_strlen(info),
-				      k1, SHA512_MAC_LEN);
+	res = dpp_hkdf_expand(hash_len, prk, hash_len, info, k1, hash_len);
 	os_memset(prk, 0, hash_len);
 	if (res < 0)
 		return -1;
@@ -958,32 +1000,14 @@ static int dpp_derive_k2(const u8 *Nx, size_t Nx_len, u8 *k2,
 
 	/* HKDF-Extract(<>, N.x) */
 	os_memset(salt, 0, hash_len);
-	if (hash_len == 32)
-		res = hmac_sha256(salt, SHA256_MAC_LEN, Nx, Nx_len, prk);
-	else if (hash_len == 48)
-		res = hmac_sha384(salt, SHA384_MAC_LEN, Nx, Nx_len, prk);
-	else if (hash_len == 64)
-		res = hmac_sha512(salt, SHA512_MAC_LEN, Nx, Nx_len, prk);
-	else
-		res = -1;
+	res = dpp_hmac(hash_len, salt, hash_len, Nx, Nx_len, prk);
 	if (res < 0)
 		return -1;
 	wpa_hexdump_key(MSG_DEBUG, "DPP: PRK = HKDF-Extract(<>, IKM=N.x)",
 			prk, hash_len);
 
 	/* HKDF-Expand(PRK, info, L) */
-	if (hash_len == 32)
-		res = hmac_sha256_kdf(prk, SHA256_MAC_LEN, NULL,
-				      (const u8 *) info, os_strlen(info),
-				      k2, SHA256_MAC_LEN);
-	else if (hash_len == 48)
-		res = hmac_sha384_kdf(prk, SHA384_MAC_LEN, NULL,
-				      (const u8 *) info, os_strlen(info),
-				      k2, SHA384_MAC_LEN);
-	else if (hash_len == 64)
-		res = hmac_sha512_kdf(prk, SHA512_MAC_LEN, NULL,
-				      (const u8 *) info, os_strlen(info),
-				      k2, SHA512_MAC_LEN);
+	res = dpp_hkdf_expand(hash_len, prk, hash_len, info, k2, hash_len);
 	os_memset(prk, 0, hash_len);
 	if (res < 0)
 		return -1;
@@ -1023,35 +1047,15 @@ static int dpp_derive_ke(struct dpp_authentication *auth, u8 *ke,
 		len[num_elem] = auth->secret_len;
 		num_elem++;
 	}
-	if (hash_len == 32)
-		res = hmac_sha256_vector(nonces, 2 * nonce_len,
-					 num_elem, addr, len, prk);
-	else if (hash_len == 48)
-		res = hmac_sha384_vector(nonces, 2 * nonce_len,
-					 num_elem, addr, len, prk);
-	else if (hash_len == 64)
-		res = hmac_sha512_vector(nonces, 2 * nonce_len,
-					 num_elem, addr, len, prk);
-	else
-		res = -1;
+	res = dpp_hmac_vector(hash_len, nonces, 2 * nonce_len,
+			      num_elem, addr, len, prk);
 	if (res < 0)
 		return -1;
 	wpa_hexdump_key(MSG_DEBUG, "DPP: PRK = HKDF-Extract(<>, IKM)",
 			prk, hash_len);
 
 	/* HKDF-Expand(PRK, info, L) */
-	if (hash_len == 32)
-		res = hmac_sha256_kdf(prk, SHA256_MAC_LEN, NULL,
-				      (const u8 *) info_ke, os_strlen(info_ke),
-				      ke, SHA256_MAC_LEN);
-	else if (hash_len == 48)
-		res = hmac_sha384_kdf(prk, SHA384_MAC_LEN, NULL,
-				      (const u8 *) info_ke, os_strlen(info_ke),
-				      ke, SHA384_MAC_LEN);
-	else if (hash_len == 64)
-		res = hmac_sha512_kdf(prk, SHA512_MAC_LEN, NULL,
-				      (const u8 *) info_ke, os_strlen(info_ke),
-				      ke, SHA512_MAC_LEN);
+	res = dpp_hkdf_expand(hash_len, prk, hash_len, info_ke, ke, hash_len);
 	os_memset(prk, 0, hash_len);
 	if (res < 0)
 		return -1;
@@ -1341,14 +1345,7 @@ static int dpp_gen_r_auth(struct dpp_authentication *auth, u8 *r_auth)
 	wpa_printf(MSG_DEBUG, "DPP: R-auth hash components");
 	for (i = 0; i < num_elem; i++)
 		wpa_hexdump(MSG_DEBUG, "DPP: hash component", addr[i], len[i]);
-	if (auth->curve->hash_len == 32)
-		res = sha256_vector(num_elem, addr, len, r_auth);
-	else if (auth->curve->hash_len == 48)
-		res = sha384_vector(num_elem, addr, len, r_auth);
-	else if (auth->curve->hash_len == 64)
-		res = sha512_vector(num_elem, addr, len, r_auth);
-	else
-		res = -1;
+	res = dpp_hash_vector(auth->curve, num_elem, addr, len, r_auth);
 	if (res == 0)
 		wpa_hexdump(MSG_DEBUG, "DPP: R-auth", r_auth,
 			    auth->curve->hash_len);
@@ -1431,14 +1428,7 @@ static int dpp_gen_i_auth(struct dpp_authentication *auth, u8 *i_auth)
 	wpa_printf(MSG_DEBUG, "DPP: I-auth hash components");
 	for (i = 0; i < num_elem; i++)
 		wpa_hexdump(MSG_DEBUG, "DPP: hash component", addr[i], len[i]);
-	if (auth->curve->hash_len == 32)
-		res = sha256_vector(num_elem, addr, len, i_auth);
-	else if (auth->curve->hash_len == 48)
-		res = sha384_vector(num_elem, addr, len, i_auth);
-	else if (auth->curve->hash_len == 64)
-		res = sha512_vector(num_elem, addr, len, i_auth);
-	else
-		res = -1;
+	res = dpp_hash_vector(auth->curve, num_elem, addr, len, i_auth);
 	if (res == 0)
 		wpa_hexdump(MSG_DEBUG, "DPP: I-auth", i_auth,
 			    auth->curve->hash_len);
@@ -4338,40 +4328,19 @@ static int dpp_derive_pmk(const u8 *Nx, size_t Nx_len, u8 *pmk,
 {
 	u8 salt[DPP_MAX_HASH_LEN], prk[DPP_MAX_HASH_LEN];
 	const char *info = "DPP PMK";
-	int res = -1;
+	int res;
 
 	/* PMK = HKDF(<>, "DPP PMK", N.x) */
 
 	/* HKDF-Extract(<>, N.x) */
 	os_memset(salt, 0, hash_len);
-	if (hash_len == 32) {
-		if (hmac_sha256(salt, SHA256_MAC_LEN, Nx, Nx_len, prk) < 0)
-			return -1;
-	} else if (hash_len == 48) {
-		if (hmac_sha384(salt, SHA384_MAC_LEN, Nx, Nx_len, prk) < 0)
-			return -1;
-	} else if (hash_len == 64) {
-		if (hmac_sha512(salt, SHA512_MAC_LEN, Nx, Nx_len, prk) < 0)
-			return -1;
-	} else {
+	if (dpp_hmac(hash_len, salt, hash_len, Nx, Nx_len, prk) < 0)
 		return -1;
-	}
 	wpa_hexdump_key(MSG_DEBUG, "DPP: PRK = HKDF-Extract(<>, IKM=N.x)",
 			prk, hash_len);
 
 	/* HKDF-Expand(PRK, info, L) */
-	if (hash_len == 32)
-		res = hmac_sha256_kdf(prk, SHA256_MAC_LEN, NULL,
-				      (const u8 *) info, os_strlen(info),
-				      pmk, SHA256_MAC_LEN);
-	else if (hash_len == 48)
-		res = hmac_sha384_kdf(prk, SHA384_MAC_LEN, NULL,
-				      (const u8 *) info, os_strlen(info),
-				      pmk, SHA384_MAC_LEN);
-	else if (hash_len == 64)
-		res = hmac_sha512_kdf(prk, SHA512_MAC_LEN, NULL,
-				      (const u8 *) info, os_strlen(info),
-				      pmk, SHA512_MAC_LEN);
+	res = dpp_hkdf_expand(hash_len, prk, hash_len, info, pmk, hash_len);
 	os_memset(prk, 0, hash_len);
 	if (res < 0)
 		return -1;
@@ -4410,14 +4379,7 @@ static int dpp_derive_pmkid(const struct dpp_curve_params *curve,
 		   (unsigned int) curve->hash_len * 8);
 	wpa_hexdump(MSG_DEBUG, "DPP: PMKID hash payload 1", addr[0], len[0]);
 	wpa_hexdump(MSG_DEBUG, "DPP: PMKID hash payload 2", addr[1], len[1]);
-	if (curve->hash_len == 32)
-		res = sha256_vector(2, addr, len, hash);
-	else if (curve->hash_len == 48)
-		res = sha384_vector(2, addr, len, hash);
-	else if (curve->hash_len == 64)
-		res = sha512_vector(2, addr, len, hash);
-	else
-		res = -1;
+	res = dpp_hash_vector(curve, 2, addr, len, hash);
 	if (res < 0)
 		goto fail;
 	wpa_hexdump(MSG_DEBUG, "DPP: PMKID hash output",