lib80211: Remove VLA usage of skcipher

In the quest to remove all stack VLA usage from the kernel[1], this
replaces struct crypto_skcipher and SKCIPHER_REQUEST_ON_STACK() usage
with struct crypto_sync_skcipher and SYNC_SKCIPHER_REQUEST_ON_STACK(),
which uses a fixed stack size.

[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com

Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: linux-wireless@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 16 insertions, 18 deletions

diff --git a/net/wireless/lib80211_crypt_tkip.c b/net/wireless/lib80211_crypt_tkip.c
index e6bce1f130c9..346e19cbdf59 100644
--- a/net/wireless/lib80211_crypt_tkip.c
+++ b/net/wireless/lib80211_crypt_tkip.c
@@ -64,9 +64,9 @@ struct lib80211_tkip_data {
 
 	int key_idx;
 
-	struct crypto_skcipher *rx_tfm_arc4;
+	struct crypto_sync_skcipher *rx_tfm_arc4;
 	struct crypto_shash *rx_tfm_michael;
-	struct crypto_skcipher *tx_tfm_arc4;
+	struct crypto_sync_skcipher *tx_tfm_arc4;
 	struct crypto_shash *tx_tfm_michael;
 
 	/* scratch buffers for virt_to_page() (crypto API) */
@@ -99,8 +99,7 @@ static void *lib80211_tkip_init(int key_idx)
 
 	priv->key_idx = key_idx;
 
-	priv->tx_tfm_arc4 = crypto_alloc_skcipher("ecb(arc4)", 0,
-						  CRYPTO_ALG_ASYNC);
+	priv->tx_tfm_arc4 = crypto_alloc_sync_skcipher("ecb(arc4)", 0, 0);
 	if (IS_ERR(priv->tx_tfm_arc4)) {
 		priv->tx_tfm_arc4 = NULL;
 		goto fail;
@@ -112,8 +111,7 @@ static void *lib80211_tkip_init(int key_idx)
 		goto fail;
 	}
 
-	priv->rx_tfm_arc4 = crypto_alloc_skcipher("ecb(arc4)", 0,
-						  CRYPTO_ALG_ASYNC);
+	priv->rx_tfm_arc4 = crypto_alloc_sync_skcipher("ecb(arc4)", 0, 0);
 	if (IS_ERR(priv->rx_tfm_arc4)) {
 		priv->rx_tfm_arc4 = NULL;
 		goto fail;
@@ -130,9 +128,9 @@ static void *lib80211_tkip_init(int key_idx)
       fail:
 	if (priv) {
 		crypto_free_shash(priv->tx_tfm_michael);
-		crypto_free_skcipher(priv->tx_tfm_arc4);
+		crypto_free_sync_skcipher(priv->tx_tfm_arc4);
 		crypto_free_shash(priv->rx_tfm_michael);
-		crypto_free_skcipher(priv->rx_tfm_arc4);
+		crypto_free_sync_skcipher(priv->rx_tfm_arc4);
 		kfree(priv);
 	}
 
@@ -144,9 +142,9 @@ static void lib80211_tkip_deinit(void *priv)
 	struct lib80211_tkip_data *_priv = priv;
 	if (_priv) {
 		crypto_free_shash(_priv->tx_tfm_michael);
-		crypto_free_skcipher(_priv->tx_tfm_arc4);
+		crypto_free_sync_skcipher(_priv->tx_tfm_arc4);
 		crypto_free_shash(_priv->rx_tfm_michael);
-		crypto_free_skcipher(_priv->rx_tfm_arc4);
+		crypto_free_sync_skcipher(_priv->rx_tfm_arc4);
 	}
 	kfree(priv);
 }
@@ -344,7 +342,7 @@ static int lib80211_tkip_hdr(struct sk_buff *skb, int hdr_len,
 static int lib80211_tkip_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
 {
 	struct lib80211_tkip_data *tkey = priv;
-	SKCIPHER_REQUEST_ON_STACK(req, tkey->tx_tfm_arc4);
+	SYNC_SKCIPHER_REQUEST_ON_STACK(req, tkey->tx_tfm_arc4);
 	int len;
 	u8 rc4key[16], *pos, *icv;
 	u32 crc;
@@ -374,9 +372,9 @@ static int lib80211_tkip_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
 	icv[2] = crc >> 16;
 	icv[3] = crc >> 24;
 
-	crypto_skcipher_setkey(tkey->tx_tfm_arc4, rc4key, 16);
+	crypto_sync_skcipher_setkey(tkey->tx_tfm_arc4, rc4key, 16);
 	sg_init_one(&sg, pos, len + 4);
-	skcipher_request_set_tfm(req, tkey->tx_tfm_arc4);
+	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);
 	err = crypto_skcipher_encrypt(req);
@@ -400,7 +398,7 @@ static inline int tkip_replay_check(u32 iv32_n, u16 iv16_n,
 static int lib80211_tkip_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
 {
 	struct lib80211_tkip_data *tkey = priv;
-	SKCIPHER_REQUEST_ON_STACK(req, tkey->rx_tfm_arc4);
+	SYNC_SKCIPHER_REQUEST_ON_STACK(req, tkey->rx_tfm_arc4);
 	u8 rc4key[16];
 	u8 keyidx, *pos;
 	u32 iv32;
@@ -463,9 +461,9 @@ static int lib80211_tkip_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
 
 	plen = skb->len - hdr_len - 12;
 
-	crypto_skcipher_setkey(tkey->rx_tfm_arc4, rc4key, 16);
+	crypto_sync_skcipher_setkey(tkey->rx_tfm_arc4, rc4key, 16);
 	sg_init_one(&sg, pos, plen + 4);
-	skcipher_request_set_tfm(req, tkey->rx_tfm_arc4);
+	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);
@@ -660,9 +658,9 @@ static int lib80211_tkip_set_key(void *key, int len, u8 * seq, void *priv)
 	struct lib80211_tkip_data *tkey = priv;
 	int keyidx;
 	struct crypto_shash *tfm = tkey->tx_tfm_michael;
-	struct crypto_skcipher *tfm2 = tkey->tx_tfm_arc4;
+	struct crypto_sync_skcipher *tfm2 = tkey->tx_tfm_arc4;
 	struct crypto_shash *tfm3 = tkey->rx_tfm_michael;
-	struct crypto_skcipher *tfm4 = tkey->rx_tfm_arc4;
+	struct crypto_sync_skcipher *tfm4 = tkey->rx_tfm_arc4;
 
 	keyidx = tkey->key_idx;
 	memset(tkey, 0, sizeof(*tkey));