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Commit 5f9f1812 authored by Felix Fietkau's avatar Felix Fietkau Committed by John W. Linville
Browse files

mac80211: remove the dependency on crypto_blkcipher 



The only thing that using crypto_blkcipher with ecb does over just using
arc4 directly is wrapping the encrypt/decrypt function into a for loop,
looping over each individual character.
To be able to do this, it pulls in around 40 kb worth of unnecessary
kernel modules (at least on a MIPS embedded device).
Using arc4 directly not only eliminates those dependencies, it also makes
the code smaller.

Signed-off-by: default avatarFelix Fietkau <nbd@openwrt.org>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 203afeca

net/mac80211/Kconfig

+0 −1
Original line number Diff line number Diff line
@@ -2,7 +2,6 @@ config MAC80211 
	tristate "Generic IEEE 802.11 Networking Stack (mac80211)"

	depends on CFG80211

	select CRYPTO

	select CRYPTO_ECB

	select CRYPTO_ARC4

	select CRYPTO_AES

	select CRC32

net/mac80211/ieee80211_i.h

+2 −2
Original line number Diff line number Diff line
@@ -809,8 +809,8 @@ struct ieee80211_local { 


	struct rate_control_ref *rate_ctrl;



	struct crypto_blkcipher *wep_tx_tfm;

	struct crypto_blkcipher *wep_rx_tfm;

	struct crypto_cipher *wep_tx_tfm;

	struct crypto_cipher *wep_rx_tfm;

	u32 wep_iv;



	/* see iface.c */

net/mac80211/tkip.c

+2 −2
Original line number Diff line number Diff line
@@ -202,7 +202,7 @@ EXPORT_SYMBOL(ieee80211_get_tkip_key); 
 * @payload_len is the length of payload (_not_ including IV/ICV length).

 * @ta is the transmitter addresses.

 */

int ieee80211_tkip_encrypt_data(struct crypto_blkcipher *tfm,

int ieee80211_tkip_encrypt_data(struct crypto_cipher *tfm,

				struct ieee80211_key *key,

				u8 *pos, size_t payload_len, u8 *ta)

{
@@ -223,7 +223,7 @@ int ieee80211_tkip_encrypt_data(struct crypto_blkcipher *tfm, 
 * beginning of the buffer containing IEEE 802.11 header payload, i.e.,

 * including IV, Ext. IV, real data, Michael MIC, ICV. @payload_len is the

 * length of payload, including IV, Ext. IV, MIC, ICV.  */

int ieee80211_tkip_decrypt_data(struct crypto_blkcipher *tfm,

int ieee80211_tkip_decrypt_data(struct crypto_cipher *tfm,

				struct ieee80211_key *key,

				u8 *payload, size_t payload_len, u8 *ta,

				u8 *ra, int only_iv, int queue,

net/mac80211/tkip.h

+2 −2
Original line number Diff line number Diff line
@@ -15,7 +15,7 @@ 


u8 *ieee80211_tkip_add_iv(u8 *pos, struct ieee80211_key *key, u16 iv16);



int ieee80211_tkip_encrypt_data(struct crypto_blkcipher *tfm,

int ieee80211_tkip_encrypt_data(struct crypto_cipher *tfm,

				 struct ieee80211_key *key,

				 u8 *pos, size_t payload_len, u8 *ta);

enum {
@@ -24,7 +24,7 @@ enum { 
	TKIP_DECRYPT_INVALID_KEYIDX = -2,

	TKIP_DECRYPT_REPLAY = -3,

};

int ieee80211_tkip_decrypt_data(struct crypto_blkcipher *tfm,

int ieee80211_tkip_decrypt_data(struct crypto_cipher *tfm,

				struct ieee80211_key *key,

				u8 *payload, size_t payload_len, u8 *ta,

				u8 *ra, int only_iv, int queue,

net/mac80211/wep.c

+15 −19
Original line number Diff line number Diff line
@@ -30,17 +30,15 @@ int ieee80211_wep_init(struct ieee80211_local *local) 
	/* start WEP IV from a random value */

	get_random_bytes(&local->wep_iv, WEP_IV_LEN);



	local->wep_tx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0,

						CRYPTO_ALG_ASYNC);

	local->wep_tx_tfm = crypto_alloc_cipher("arc4", 0, CRYPTO_ALG_ASYNC);

	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_blkcipher("ecb(arc4)", 0,

						CRYPTO_ALG_ASYNC);

	local->wep_rx_tfm = crypto_alloc_cipher("arc4", 0, CRYPTO_ALG_ASYNC);

	if (IS_ERR(local->wep_rx_tfm)) {

		crypto_free_blkcipher(local->wep_tx_tfm);

		crypto_free_cipher(local->wep_tx_tfm);

		local->wep_tx_tfm = ERR_PTR(-EINVAL);

		return PTR_ERR(local->wep_rx_tfm);

	}
@@ -51,9 +49,9 @@ int ieee80211_wep_init(struct ieee80211_local *local) 
void ieee80211_wep_free(struct ieee80211_local *local)

{

	if (!IS_ERR(local->wep_tx_tfm))

		crypto_free_blkcipher(local->wep_tx_tfm);

		crypto_free_cipher(local->wep_tx_tfm);

	if (!IS_ERR(local->wep_rx_tfm))

		crypto_free_blkcipher(local->wep_rx_tfm);

		crypto_free_cipher(local->wep_rx_tfm);

}



static inline bool ieee80211_wep_weak_iv(u32 iv, int keylen)
@@ -127,12 +125,11 @@ 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_blkcipher *tfm, u8 *rc4key,

int ieee80211_wep_encrypt_data(struct crypto_cipher *tfm, u8 *rc4key,

			       size_t klen, u8 *data, size_t data_len)

{

	struct blkcipher_desc desc = { .tfm = tfm };

	struct scatterlist sg;

	__le32 icv;

	int i;



	if (IS_ERR(tfm))

		return -1;
@@ -140,9 +137,9 @@ int ieee80211_wep_encrypt_data(struct crypto_blkcipher *tfm, u8 *rc4key, 
	icv = cpu_to_le32(~crc32_le(~0, data, data_len));

	put_unaligned(icv, (__le32 *)(data + data_len));



	crypto_blkcipher_setkey(tfm, rc4key, klen);

	sg_init_one(&sg, data, data_len + WEP_ICV_LEN);

	crypto_blkcipher_encrypt(&desc, &sg, &sg, sg.length);

	crypto_cipher_setkey(tfm, rc4key, klen);

	for (i = 0; i < data_len + WEP_ICV_LEN; i++)

		crypto_cipher_encrypt_one(tfm, data + i, data + i);



	return 0;

}
@@ -186,19 +183,18 @@ 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_blkcipher *tfm, u8 *rc4key,

int ieee80211_wep_decrypt_data(struct crypto_cipher *tfm, u8 *rc4key,

			       size_t klen, u8 *data, size_t data_len)

{

	struct blkcipher_desc desc = { .tfm = tfm };

	struct scatterlist sg;

	__le32 crc;

	int i;



	if (IS_ERR(tfm))

		return -1;



	crypto_blkcipher_setkey(tfm, rc4key, klen);

	sg_init_one(&sg, data, data_len + WEP_ICV_LEN);

	crypto_blkcipher_decrypt(&desc, &sg, &sg, sg.length);

	crypto_cipher_setkey(tfm, rc4key, klen);

	for (i = 0; i < data_len + WEP_ICV_LEN; i++)

		crypto_cipher_decrypt_one(tfm, data + i, data + i);



	crc = cpu_to_le32(~crc32_le(~0, data, data_len));

	if (memcmp(&crc, data + data_len, WEP_ICV_LEN) != 0)