[PATCH v5 3/7] net/lib80211: move WEP handling to ARC4 library code

[Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>]

The crypto API abstraction is not very useful for invoking ciphers
directly, especially in the case of arc4, which only has a generic
implementation in C. So let's invoke the library code directly.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
 net/wireless/Kconfig              |  1 +
 net/wireless/lib80211_crypt_wep.c | 51 +++++---------------
 2 files changed, 14 insertions(+), 38 deletions(-)

diff --git a/net/wireless/Kconfig b/net/wireless/Kconfig
index 6310ddede220..6d9c48cea07e 100644
--- a/net/wireless/Kconfig
+++ b/net/wireless/Kconfig
@@ -213,6 +213,7 @@ config LIB80211
 
 config LIB80211_CRYPT_WEP
 	tristate
+	select CRYPTO_LIB_ARC4
 
 config LIB80211_CRYPT_CCMP
 	tristate
diff --git a/net/wireless/lib80211_crypt_wep.c b/net/wireless/lib80211_crypt_wep.c
index 20c1ad63ad44..04e4d66ea19d 100644
--- a/net/wireless/lib80211_crypt_wep.c
+++ b/net/wireless/lib80211_crypt_wep.c
@@ -11,6 +11,7 @@
  */
 
 #include <linux/err.h>
+#include <linux/fips.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/slab.h>
@@ -22,7 +23,7 @@
 
 #include <net/lib80211.h>
 
-#include <linux/crypto.h>
+#include <crypto/arc4.h>
 #include <linux/crc32.h>
 
 MODULE_AUTHOR("Jouni Malinen");
@@ -35,52 +36,31 @@ struct lib80211_wep_data {
 	u8 key[WEP_KEY_LEN + 1];
 	u8 key_len;
 	u8 key_idx;
-	struct crypto_cipher *tx_tfm;
-	struct crypto_cipher *rx_tfm;
+	struct arc4_ctx tx_ctx;
+	struct arc4_ctx rx_ctx;
 };
 
 static void *lib80211_wep_init(int keyidx)
 {
 	struct lib80211_wep_data *priv;
 
+	if (fips_enabled)
+		return NULL;
+
 	priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
 	if (priv == NULL)
-		goto fail;
+		return NULL;
 	priv->key_idx = keyidx;
 
-	priv->tx_tfm = crypto_alloc_cipher("arc4", 0, 0);
-	if (IS_ERR(priv->tx_tfm)) {
-		priv->tx_tfm = NULL;
-		goto fail;
-	}
-
-	priv->rx_tfm = crypto_alloc_cipher("arc4", 0, 0);
-	if (IS_ERR(priv->rx_tfm)) {
-		priv->rx_tfm = NULL;
-		goto fail;
-	}
 	/* start WEP IV from a random value */
 	get_random_bytes(&priv->iv, 4);
 
 	return priv;
-
-      fail:
-	if (priv) {
-		crypto_free_cipher(priv->tx_tfm);
-		crypto_free_cipher(priv->rx_tfm);
-		kfree(priv);
-	}
-	return NULL;
 }
 
 static void lib80211_wep_deinit(void *priv)
 {
-	struct lib80211_wep_data *_priv = priv;
-	if (_priv) {
-		crypto_free_cipher(_priv->tx_tfm);
-		crypto_free_cipher(_priv->rx_tfm);
-	}
-	kfree(priv);
+	kzfree(priv);
 }
 
 /* Add WEP IV/key info to a frame that has at least 4 bytes of headroom */
@@ -132,7 +112,6 @@ static int lib80211_wep_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
 	u32 crc, klen, len;
 	u8 *pos, *icv;
 	u8 key[WEP_KEY_LEN + 3];
-	int i;
 
 	/* other checks are in lib80211_wep_build_iv */
 	if (skb_tailroom(skb) < 4)
@@ -160,10 +139,8 @@ static int lib80211_wep_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
 	icv[2] = crc >> 16;
 	icv[3] = crc >> 24;
 
-	crypto_cipher_setkey(wep->tx_tfm, key, klen);
-
-	for (i = 0; i < len + 4; i++)
-		crypto_cipher_encrypt_one(wep->tx_tfm, pos + i, pos + i);
+	arc4_setkey(&wep->tx_ctx, key, klen);
+	arc4_crypt(&wep->tx_ctx, pos, pos, len + 4);
 
 	return 0;
 }
@@ -181,7 +158,6 @@ static int lib80211_wep_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
 	u32 crc, klen, plen;
 	u8 key[WEP_KEY_LEN + 3];
 	u8 keyidx, *pos, icv[4];
-	int i;
 
 	if (skb->len < hdr_len + 8)
 		return -1;
@@ -202,9 +178,8 @@ static int lib80211_wep_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
 	/* Apply RC4 to data and compute CRC32 over decrypted data */
 	plen = skb->len - hdr_len - 8;
 
-	crypto_cipher_setkey(wep->rx_tfm, key, klen);
-	for (i = 0; i < plen + 4; i++)
-		crypto_cipher_decrypt_one(wep->rx_tfm, pos + i, pos + i);
+	arc4_setkey(&wep->rx_ctx, key, klen);
+	arc4_crypt(&wep->rx_ctx, pos, pos, plen + 4);
 
 	crc = ~crc32_le(~0, pos, plen);
 	icv[0] = crc;
-- 
2.20.1