[RFC PATCH 2/7] staging/rtl8192u: switch to RC4 library interface

From: Ard Biesheuvel
Date: Thu Jul 02 2020 - 06:23:06 EST


Switch to the ARC4 library interface, to remove the pointless
dependency on the skcipher API, from which we will hopefully be
able to drop ecb(arc4) skcipher support.

Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
---
drivers/staging/rtl8192u/Kconfig | 1 +
drivers/staging/rtl8192u/ieee80211/ieee80211_crypt_tkip.c | 82 ++++----------------
drivers/staging/rtl8192u/ieee80211/ieee80211_crypt_wep.c | 64 +++------------
3 files changed, 27 insertions(+), 120 deletions(-)

diff --git a/drivers/staging/rtl8192u/Kconfig b/drivers/staging/rtl8192u/Kconfig
index 1edca5c304fb..ef883d462d3d 100644
--- a/drivers/staging/rtl8192u/Kconfig
+++ b/drivers/staging/rtl8192u/Kconfig
@@ -8,3 +8,4 @@ config RTL8192U
select CRYPTO
select CRYPTO_AES
select CRYPTO_CCM
+ select CRYPTO_LIB_ARC4
diff --git a/drivers/staging/rtl8192u/ieee80211/ieee80211_crypt_tkip.c b/drivers/staging/rtl8192u/ieee80211/ieee80211_crypt_tkip.c
index ffe624ed0c0c..a315133c20db 100644
--- a/drivers/staging/rtl8192u/ieee80211/ieee80211_crypt_tkip.c
+++ b/drivers/staging/rtl8192u/ieee80211/ieee80211_crypt_tkip.c
@@ -5,6 +5,7 @@
* Copyright (c) 2003-2004, Jouni Malinen <jkmaline@xxxxxxxxx>
*/

+#include <linux/fips.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
@@ -17,9 +18,7 @@

#include "ieee80211.h"

-#include <crypto/hash.h>
-#include <crypto/skcipher.h>
- #include <linux/scatterlist.h>
+#include <crypto/arc4.h>
#include <linux/crc32.h>

MODULE_AUTHOR("Jouni Malinen");
@@ -49,9 +48,9 @@ struct ieee80211_tkip_data {

int key_idx;

- struct crypto_sync_skcipher *rx_tfm_arc4;
+ struct arc4_ctx rx_ctx_arc4;
+ struct arc4_ctx tx_ctx_arc4;
struct crypto_shash *rx_tfm_michael;
- struct crypto_sync_skcipher *tx_tfm_arc4;
struct crypto_shash *tx_tfm_michael;

/* scratch buffers for virt_to_page() (crypto API) */
@@ -62,19 +61,14 @@ static void *ieee80211_tkip_init(int key_idx)
{
struct ieee80211_tkip_data *priv;

+ if (fips_enabled)
+ return NULL;
+
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (!priv)
goto fail;
priv->key_idx = key_idx;

- priv->tx_tfm_arc4 = crypto_alloc_sync_skcipher("ecb(arc4)", 0, 0);
- if (IS_ERR(priv->tx_tfm_arc4)) {
- printk(KERN_DEBUG "ieee80211_crypt_tkip: could not allocate "
- "crypto API arc4\n");
- priv->tx_tfm_arc4 = NULL;
- goto fail;
- }
-
priv->tx_tfm_michael = crypto_alloc_shash("michael_mic", 0, 0);
if (IS_ERR(priv->tx_tfm_michael)) {
printk(KERN_DEBUG "ieee80211_crypt_tkip: could not allocate "
@@ -83,14 +77,6 @@ static void *ieee80211_tkip_init(int key_idx)
goto fail;
}

- priv->rx_tfm_arc4 = crypto_alloc_sync_skcipher("ecb(arc4)", 0, 0);
- if (IS_ERR(priv->rx_tfm_arc4)) {
- printk(KERN_DEBUG "ieee80211_crypt_tkip: could not allocate "
- "crypto API arc4\n");
- priv->rx_tfm_arc4 = NULL;
- goto fail;
- }
-
priv->rx_tfm_michael = crypto_alloc_shash("michael_mic", 0, 0);
if (IS_ERR(priv->rx_tfm_michael)) {
printk(KERN_DEBUG "ieee80211_crypt_tkip: could not allocate "
@@ -104,9 +90,7 @@ static void *ieee80211_tkip_init(int key_idx)
fail:
if (priv) {
crypto_free_shash(priv->tx_tfm_michael);
- crypto_free_sync_skcipher(priv->tx_tfm_arc4);
crypto_free_shash(priv->rx_tfm_michael);
- crypto_free_sync_skcipher(priv->rx_tfm_arc4);
kfree(priv);
}

@@ -120,11 +104,9 @@ static void ieee80211_tkip_deinit(void *priv)

if (_priv) {
crypto_free_shash(_priv->tx_tfm_michael);
- crypto_free_sync_skcipher(_priv->tx_tfm_arc4);
crypto_free_shash(_priv->rx_tfm_michael);
- crypto_free_sync_skcipher(_priv->rx_tfm_arc4);
}
- kfree(priv);
+ kzfree(priv);
}


@@ -290,10 +272,8 @@ static int ieee80211_tkip_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
u8 *pos;
struct rtl_80211_hdr_4addr *hdr;
struct cb_desc *tcb_desc = (struct cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
- int ret = 0;
u8 rc4key[16], *icv;
u32 crc;
- struct scatterlist sg;

if (skb_headroom(skb) < 8 || skb_tailroom(skb) < 4 ||
skb->len < hdr_len)
@@ -334,21 +314,15 @@ static int ieee80211_tkip_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
*pos++ = (tkey->tx_iv32 >> 24) & 0xff;

if (!tcb_desc->bHwSec) {
- SYNC_SKCIPHER_REQUEST_ON_STACK(req, tkey->tx_tfm_arc4);
-
icv = skb_put(skb, 4);
crc = ~crc32_le(~0, pos, len);
icv[0] = crc;
icv[1] = crc >> 8;
icv[2] = crc >> 16;
icv[3] = crc >> 24;
- crypto_sync_skcipher_setkey(tkey->tx_tfm_arc4, rc4key, 16);
- sg_init_one(&sg, pos, len + 4);
- skcipher_request_set_sync_tfm(req, tkey->tx_tfm_arc4);
- skcipher_request_set_callback(req, 0, NULL, NULL);
- skcipher_request_set_crypt(req, &sg, &sg, len + 4, NULL);
- ret = crypto_skcipher_encrypt(req);
- skcipher_request_zero(req);
+
+ arc4_setkey(&tkey->tx_ctx_arc4, rc4key, 16);
+ arc4_crypt(&tkey->tx_ctx_arc4, pos, pos, len + 4);
}

tkey->tx_iv16++;
@@ -357,12 +331,7 @@ static int ieee80211_tkip_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
tkey->tx_iv32++;
}

- if (!tcb_desc->bHwSec)
- return ret;
- else
- return 0;
-
-
+ return 0;
}

static int ieee80211_tkip_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
@@ -376,9 +345,7 @@ static int ieee80211_tkip_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
u8 rc4key[16];
u8 icv[4];
u32 crc;
- struct scatterlist sg;
int plen;
- int err;

if (skb->len < hdr_len + 8 + 4)
return -1;
@@ -412,8 +379,6 @@ static int ieee80211_tkip_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
pos += 8;

if (!tcb_desc->bHwSec) {
- SYNC_SKCIPHER_REQUEST_ON_STACK(req, tkey->rx_tfm_arc4);
-
if (iv32 < tkey->rx_iv32 ||
(iv32 == tkey->rx_iv32 && iv16 <= tkey->rx_iv16)) {
if (net_ratelimit()) {
@@ -434,23 +399,8 @@ static int ieee80211_tkip_decrypt(struct sk_buff *skb, int hdr_len, void *priv)

plen = skb->len - hdr_len - 12;

- crypto_sync_skcipher_setkey(tkey->rx_tfm_arc4, rc4key, 16);
- sg_init_one(&sg, pos, plen + 4);
-
- skcipher_request_set_sync_tfm(req, tkey->rx_tfm_arc4);
- skcipher_request_set_callback(req, 0, NULL, NULL);
- skcipher_request_set_crypt(req, &sg, &sg, plen + 4, NULL);
-
- err = crypto_skcipher_decrypt(req);
- skcipher_request_zero(req);
- if (err) {
- if (net_ratelimit()) {
- netdev_dbg(skb->dev, "TKIP: failed to decrypt "
- "received packet from %pM\n",
- hdr->addr2);
- }
- return -7;
- }
+ arc4_setkey(&tkey->rx_ctx_arc4, rc4key, 16);
+ arc4_crypt(&tkey->rx_ctx_arc4, pos, pos, plen + 4);

crc = ~crc32_le(~0, pos, plen);
icv[0] = crc;
@@ -655,17 +605,13 @@ static int ieee80211_tkip_set_key(void *key, int len, u8 *seq, void *priv)
struct ieee80211_tkip_data *tkey = priv;
int keyidx;
struct crypto_shash *tfm = tkey->tx_tfm_michael;
- struct crypto_sync_skcipher *tfm2 = tkey->tx_tfm_arc4;
struct crypto_shash *tfm3 = tkey->rx_tfm_michael;
- struct crypto_sync_skcipher *tfm4 = tkey->rx_tfm_arc4;

keyidx = tkey->key_idx;
memset(tkey, 0, sizeof(*tkey));
tkey->key_idx = keyidx;
tkey->tx_tfm_michael = tfm;
- tkey->tx_tfm_arc4 = tfm2;
tkey->rx_tfm_michael = tfm3;
- tkey->rx_tfm_arc4 = tfm4;

if (len == TKIP_KEY_LEN) {
memcpy(tkey->key, key, TKIP_KEY_LEN);
diff --git a/drivers/staging/rtl8192u/ieee80211/ieee80211_crypt_wep.c b/drivers/staging/rtl8192u/ieee80211/ieee80211_crypt_wep.c
index 26482c3dcd1c..1c56e2d03aae 100644
--- a/drivers/staging/rtl8192u/ieee80211/ieee80211_crypt_wep.c
+++ b/drivers/staging/rtl8192u/ieee80211/ieee80211_crypt_wep.c
@@ -5,6 +5,7 @@
* Copyright (c) 2002-2004, Jouni Malinen <jkmaline@xxxxxxxxx>
*/

+#include <linux/fips.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
@@ -14,8 +15,7 @@

#include "ieee80211.h"

-#include <crypto/skcipher.h>
-#include <linux/scatterlist.h>
+#include <crypto/arc4.h>
#include <linux/crc32.h>

MODULE_AUTHOR("Jouni Malinen");
@@ -28,8 +28,8 @@ struct prism2_wep_data {
u8 key[WEP_KEY_LEN + 1];
u8 key_len;
u8 key_idx;
- struct crypto_sync_skcipher *tx_tfm;
- struct crypto_sync_skcipher *rx_tfm;
+ struct arc4_ctx rx_ctx_arc4;
+ struct arc4_ctx tx_ctx_arc4;
};


@@ -37,39 +37,24 @@ static void *prism2_wep_init(int keyidx)
{
struct prism2_wep_data *priv;

+ if (fips_enabled)
+ return NULL;
+
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (!priv)
return NULL;
priv->key_idx = keyidx;

- priv->tx_tfm = crypto_alloc_sync_skcipher("ecb(arc4)", 0, 0);
- if (IS_ERR(priv->tx_tfm))
- goto free_priv;
- priv->rx_tfm = crypto_alloc_sync_skcipher("ecb(arc4)", 0, 0);
- if (IS_ERR(priv->rx_tfm))
- goto free_tx;
-
/* start WEP IV from a random value */
get_random_bytes(&priv->iv, 4);

return priv;
-free_tx:
- crypto_free_sync_skcipher(priv->tx_tfm);
-free_priv:
- kfree(priv);
- return NULL;
}


static void prism2_wep_deinit(void *priv)
{
- struct prism2_wep_data *_priv = priv;
-
- if (_priv) {
- crypto_free_sync_skcipher(_priv->tx_tfm);
- crypto_free_sync_skcipher(_priv->rx_tfm);
- }
- kfree(priv);
+ kzfree(priv);
}

/* Perform WEP encryption on given skb that has at least 4 bytes of headroom
@@ -87,8 +72,6 @@ static int prism2_wep_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
struct cb_desc *tcb_desc = (struct cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
u32 crc;
u8 *icv;
- struct scatterlist sg;
- int err;

if (skb_headroom(skb) < 4 || skb_tailroom(skb) < 4 ||
skb->len < hdr_len)
@@ -124,8 +107,6 @@ static int prism2_wep_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
memcpy(key + 3, wep->key, wep->key_len);

if (!tcb_desc->bHwSec) {
- SYNC_SKCIPHER_REQUEST_ON_STACK(req, wep->tx_tfm);
-
/* Append little-endian CRC32 and encrypt it to produce ICV */
crc = ~crc32_le(~0, pos, len);
icv = skb_put(skb, 4);
@@ -134,16 +115,8 @@ static int prism2_wep_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
icv[2] = crc >> 16;
icv[3] = crc >> 24;

- crypto_sync_skcipher_setkey(wep->tx_tfm, key, klen);
- sg_init_one(&sg, pos, len + 4);
-
- skcipher_request_set_sync_tfm(req, wep->tx_tfm);
- skcipher_request_set_callback(req, 0, NULL, NULL);
- skcipher_request_set_crypt(req, &sg, &sg, len + 4, NULL);
-
- err = crypto_skcipher_encrypt(req);
- skcipher_request_zero(req);
- return err;
+ arc4_setkey(&wep->tx_ctx_arc4, key, klen);
+ arc4_crypt(&wep->tx_ctx_arc4, pos, pos, len + 4);
}

return 0;
@@ -166,8 +139,6 @@ static int prism2_wep_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
struct cb_desc *tcb_desc = (struct cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
u32 crc;
u8 icv[4];
- struct scatterlist sg;
- int err;

if (skb->len < hdr_len + 8)
return -1;
@@ -189,19 +160,8 @@ static int prism2_wep_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
plen = skb->len - hdr_len - 8;

if (!tcb_desc->bHwSec) {
- SYNC_SKCIPHER_REQUEST_ON_STACK(req, wep->rx_tfm);
-
- crypto_sync_skcipher_setkey(wep->rx_tfm, key, klen);
- sg_init_one(&sg, pos, plen + 4);
-
- skcipher_request_set_sync_tfm(req, wep->rx_tfm);
- skcipher_request_set_callback(req, 0, NULL, NULL);
- skcipher_request_set_crypt(req, &sg, &sg, plen + 4, NULL);
-
- err = crypto_skcipher_decrypt(req);
- skcipher_request_zero(req);
- if (err)
- return -7;
+ arc4_setkey(&wep->rx_ctx_arc4, key, klen);
+ arc4_crypt(&wep->rx_ctx_arc4, pos, pos, plen + 4);

crc = ~crc32_le(~0, pos, plen);
icv[0] = crc;
--
2.17.1