1 files changed, 29 insertions, 26 deletions

diff --git a/drivers/net/wireguard/noise.c b/drivers/net/wireguard/noise.c
index 919d9d866446..708dc61c974f 100644
--- a/drivers/net/wireguard/noise.c
+++ b/drivers/net/wireguard/noise.c
@@ -44,32 +44,23 @@ void __init wg_noise_init(void)
 }
 
 /* Must hold peer->handshake.static_identity->lock */
-bool wg_noise_precompute_static_static(struct wg_peer *peer)
+void wg_noise_precompute_static_static(struct wg_peer *peer)
 {
-	bool ret;
-
 	down_write(&peer->handshake.lock);
-	if (peer->handshake.static_identity->has_identity) {
-		ret = curve25519(
-			peer->handshake.precomputed_static_static,
+	if (!peer->handshake.static_identity->has_identity ||
+	    !curve25519(peer->handshake.precomputed_static_static,
 			peer->handshake.static_identity->static_private,
-			peer->handshake.remote_static);
-	} else {
-		u8 empty[NOISE_PUBLIC_KEY_LEN] = { 0 };
-
-		ret = curve25519(empty, empty, peer->handshake.remote_static);
+			peer->handshake.remote_static))
 		memset(peer->handshake.precomputed_static_static, 0,
 		       NOISE_PUBLIC_KEY_LEN);
-	}
 	up_write(&peer->handshake.lock);
-	return ret;
 }
 
-bool wg_noise_handshake_init(struct noise_handshake *handshake,
-			   struct noise_static_identity *static_identity,
-			   const u8 peer_public_key[NOISE_PUBLIC_KEY_LEN],
-			   const u8 peer_preshared_key[NOISE_SYMMETRIC_KEY_LEN],
-			   struct wg_peer *peer)
+void wg_noise_handshake_init(struct noise_handshake *handshake,
+			     struct noise_static_identity *static_identity,
+			     const u8 peer_public_key[NOISE_PUBLIC_KEY_LEN],
+			     const u8 peer_preshared_key[NOISE_SYMMETRIC_KEY_LEN],
+			     struct wg_peer *peer)
 {
 	memset(handshake, 0, sizeof(*handshake));
 	init_rwsem(&handshake->lock);
@@ -81,7 +72,7 @@ bool wg_noise_handshake_init(struct noise_handshake *handshake,
 		       NOISE_SYMMETRIC_KEY_LEN);
 	handshake->static_identity = static_identity;
 	handshake->state = HANDSHAKE_ZEROED;
-	return wg_noise_precompute_static_static(peer);
+	wg_noise_precompute_static_static(peer);
 }
 
 static void handshake_zero(struct noise_handshake *handshake)
@@ -403,6 +394,19 @@ static bool __must_check mix_dh(u8 chaining_key[NOISE_HASH_LEN],
 	return true;
 }
 
+static bool __must_check mix_precomputed_dh(u8 chaining_key[NOISE_HASH_LEN],
+					    u8 key[NOISE_SYMMETRIC_KEY_LEN],
+					    const u8 precomputed[NOISE_PUBLIC_KEY_LEN])
+{
+	static u8 zero_point[NOISE_PUBLIC_KEY_LEN];
+	if (unlikely(!crypto_memneq(precomputed, zero_point, NOISE_PUBLIC_KEY_LEN)))
+		return false;
+	kdf(chaining_key, key, NULL, precomputed, NOISE_HASH_LEN,
+	    NOISE_SYMMETRIC_KEY_LEN, 0, NOISE_PUBLIC_KEY_LEN,
+	    chaining_key);
+	return true;
+}
+
 static void mix_hash(u8 hash[NOISE_HASH_LEN], const u8 *src, size_t src_len)
 {
 	struct blake2s_state blake;
@@ -531,10 +535,9 @@ wg_noise_handshake_create_initiation(struct message_handshake_initiation *dst,
 			NOISE_PUBLIC_KEY_LEN, key, handshake->hash);
 
 	/* ss */
-	kdf(handshake->chaining_key, key, NULL,
-	    handshake->precomputed_static_static, NOISE_HASH_LEN,
-	    NOISE_SYMMETRIC_KEY_LEN, 0, NOISE_PUBLIC_KEY_LEN,
-	    handshake->chaining_key);
+	if (!mix_precomputed_dh(handshake->chaining_key, key,
+				handshake->precomputed_static_static))
+		goto out;
 
 	/* {t} */
 	tai64n_now(timestamp);
@@ -595,9 +598,9 @@ wg_noise_handshake_consume_initiation(struct message_handshake_initiation *src,
 	handshake = &peer->handshake;
 
 	/* ss */
-	kdf(chaining_key, key, NULL, handshake->precomputed_static_static,
-	    NOISE_HASH_LEN, NOISE_SYMMETRIC_KEY_LEN, 0, NOISE_PUBLIC_KEY_LEN,
-	    chaining_key);
+	if (!mix_precomputed_dh(chaining_key, key,
+				handshake->precomputed_static_static))
+	    goto out;
 
 	/* {t} */
 	if (!message_decrypt(t, src->encrypted_timestamp,