SAE: Move commit element validation steps into single location

It is clearer to keep all the validation steps described in IEEE 802.11
11.3.5.4 in a single location instead of splitting this between the
parsing and processing functions.

Signed-hostap: Jouni Malinen <j@w1.fi>

src/common/sae.c

@@ -524,12 +524,6 @@ static int sae_derive_k_ecc(struct sae_data *sae, u8 *k)
 	if (K == NULL)
 		goto fail;
 
-	if (!crypto_ec_point_is_on_curve(sae->tmp->ec,
-					 sae->tmp->peer_commit_element_ecc)) {
-		wpa_printf(MSG_DEBUG, "SAE: Peer element is not on curve");
-		goto fail;
-	}
-
 	/*
 	 * K = scalar-op(rand, (elem-op(scalar-op(peer-commit-scalar, PWE),
 	 *                                        PEER-COMMIT-ELEMENT)))
@@ -821,6 +815,12 @@ static u16 sae_parse_commit_element_ecc(struct sae_data *sae, const u8 *pos,
 	if (sae->tmp->peer_commit_element_ecc == NULL)
 		return WLAN_STATUS_UNSPECIFIED_FAILURE;
 
+	if (!crypto_ec_point_is_on_curve(sae->tmp->ec,
+					 sae->tmp->peer_commit_element_ecc)) {
+		wpa_printf(MSG_DEBUG, "SAE: Peer element is not on curve");
+		return WLAN_STATUS_UNSPECIFIED_FAILURE;
+	}
+
 	return WLAN_STATUS_SUCCESS;
 }