net/mac80211: move WEP handling to ARC4 library interface

The WEP code in the mac80211 subsystem currently uses the crypto
API to access the arc4 (RC4) cipher, which is overly complicated,
and doesn't really have an upside in this particular case, since
ciphers are always synchronous and therefore always implemented in
software. Given that we have no accelerated software implementations
either, it is much more straightforward to invoke a generic library
interface directly.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 10 insertions, 39 deletions

diff --git a/net/mac80211/wep.c b/net/mac80211/wep.c
index bfe9ed9f4c48..9f5673736967 100644
--- a/net/mac80211/wep.c
+++ b/net/mac80211/wep.c
@@ -30,30 +30,9 @@ int ieee80211_wep_init(struct ieee80211_local *local)
 	/* start WEP IV from a random value */
 	get_random_bytes(&local->wep_iv, IEEE80211_WEP_IV_LEN);
 
-	local->wep_tx_tfm = crypto_alloc_cipher("arc4", 0, 0);
-	if (IS_ERR(local->wep_tx_tfm)) {
-		local->wep_rx_tfm = ERR_PTR(-EINVAL);
-		return PTR_ERR(local->wep_tx_tfm);
-	}
-
-	local->wep_rx_tfm = crypto_alloc_cipher("arc4", 0, 0);
-	if (IS_ERR(local->wep_rx_tfm)) {
-		crypto_free_cipher(local->wep_tx_tfm);
-		local->wep_tx_tfm = ERR_PTR(-EINVAL);
-		return PTR_ERR(local->wep_rx_tfm);
-	}
-
 	return 0;
 }
 
-void ieee80211_wep_free(struct ieee80211_local *local)
-{
-	if (!IS_ERR(local->wep_tx_tfm))
-		crypto_free_cipher(local->wep_tx_tfm);
-	if (!IS_ERR(local->wep_rx_tfm))
-		crypto_free_cipher(local->wep_rx_tfm);
-}
-
 static inline bool ieee80211_wep_weak_iv(u32 iv, int keylen)
 {
 	/*
@@ -131,21 +110,17 @@ static void ieee80211_wep_remove_iv(struct ieee80211_local *local,
 /* Perform WEP encryption using given key. data buffer must have tailroom
  * for 4-byte ICV. data_len must not include this ICV. Note: this function
  * does _not_ add IV. data = RC4(data | CRC32(data)) */
-int ieee80211_wep_encrypt_data(struct crypto_cipher *tfm, u8 *rc4key,
+int ieee80211_wep_encrypt_data(struct arc4_ctx *ctx, u8 *rc4key,
 			       size_t klen, u8 *data, size_t data_len)
 {
 	__le32 icv;
-	int i;
-
-	if (IS_ERR(tfm))
-		return -1;
 
 	icv = cpu_to_le32(~crc32_le(~0, data, data_len));
 	put_unaligned(icv, (__le32 *)(data + data_len));
 
-	crypto_cipher_setkey(tfm, rc4key, klen);
-	for (i = 0; i < data_len + IEEE80211_WEP_ICV_LEN; i++)
-		crypto_cipher_encrypt_one(tfm, data + i, data + i);
+	arc4_setkey(ctx, rc4key, klen);
+	arc4_crypt(ctx, data, data, data_len + IEEE80211_WEP_ICV_LEN);
+	memzero_explicit(ctx, sizeof(*ctx));
 
 	return 0;
 }
@@ -184,7 +159,7 @@ int ieee80211_wep_encrypt(struct ieee80211_local *local,
 	/* Add room for ICV */
 	skb_put(skb, IEEE80211_WEP_ICV_LEN);
 
-	return ieee80211_wep_encrypt_data(local->wep_tx_tfm, rc4key, keylen + 3,
+	return ieee80211_wep_encrypt_data(&local->wep_tx_ctx, rc4key, keylen + 3,
 					  iv + IEEE80211_WEP_IV_LEN, len);
 }
 
@@ -192,18 +167,14 @@ int ieee80211_wep_encrypt(struct ieee80211_local *local,
 /* Perform WEP decryption using given key. data buffer includes encrypted
  * payload, including 4-byte ICV, but _not_ IV. data_len must not include ICV.
  * Return 0 on success and -1 on ICV mismatch. */
-int ieee80211_wep_decrypt_data(struct crypto_cipher *tfm, u8 *rc4key,
+int ieee80211_wep_decrypt_data(struct arc4_ctx *ctx, u8 *rc4key,
 			       size_t klen, u8 *data, size_t data_len)
 {
 	__le32 crc;
-	int i;
-
-	if (IS_ERR(tfm))
-		return -1;
 
-	crypto_cipher_setkey(tfm, rc4key, klen);
-	for (i = 0; i < data_len + IEEE80211_WEP_ICV_LEN; i++)
-		crypto_cipher_decrypt_one(tfm, data + i, data + i);
+	arc4_setkey(ctx, rc4key, klen);
+	arc4_crypt(ctx, data, data, data_len + IEEE80211_WEP_ICV_LEN);
+	memzero_explicit(ctx, sizeof(*ctx));
 
 	crc = cpu_to_le32(~crc32_le(~0, data, data_len));
 	if (memcmp(&crc, data + data_len, IEEE80211_WEP_ICV_LEN) != 0)
@@ -256,7 +227,7 @@ static int ieee80211_wep_decrypt(struct ieee80211_local *local,
 	/* Copy rest of the WEP key (the secret part) */
 	memcpy(rc4key + 3, key->conf.key, key->conf.keylen);
 
-	if (ieee80211_wep_decrypt_data(local->wep_rx_tfm, rc4key, klen,
+	if (ieee80211_wep_decrypt_data(&local->wep_rx_ctx, rc4key, klen,
 				       skb->data + hdrlen +
 				       IEEE80211_WEP_IV_LEN, len))
 		ret = -1;