Re: [PATCH v3 2/7] net/mac80211: move WEP handling to ARC4 library interface

[Eric Biggers <ebiggers@kernel.org>]

On Tue, Jun 11, 2019 at 03:47:45PM +0200, Ard Biesheuvel wrote:
>  
> -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);
> -}
> -

This function was removed, but its declaration in net/mac80211/wep.h was not.

>  static inline bool ieee80211_wep_weak_iv(u32 iv, int keylen)
>  {
>  	/*
> @@ -131,21 +110,16 @@ 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);

How about adding:

	memzero_explicit(ctx, sizeof(*ctx));

> -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);

Same here.

- Eric