In preparing to remove all stack VLA usage from the kernel[1], this removes the discouraged use of AHASH_REQUEST_ON_STACK in favor of the smaller SHASH_DESC_ON_STACK by converting from ahash-wrapped-shash to direct shash. The stack allocation will be made a fixed size in a later patch to the crypto subsystem. [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@xxxxxxxxxxxxxx Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> --- net/wireless/lib80211_crypt_tkip.c | 55 ++++++++++++++++-------------- 1 file changed, 30 insertions(+), 25 deletions(-) diff --git a/net/wireless/lib80211_crypt_tkip.c b/net/wireless/lib80211_crypt_tkip.c index ba0a1f398ce5..e6bce1f130c9 100644 --- a/net/wireless/lib80211_crypt_tkip.c +++ b/net/wireless/lib80211_crypt_tkip.c @@ -65,9 +65,9 @@ struct lib80211_tkip_data { int key_idx; struct crypto_skcipher *rx_tfm_arc4; - struct crypto_ahash *rx_tfm_michael; + struct crypto_shash *rx_tfm_michael; struct crypto_skcipher *tx_tfm_arc4; - struct crypto_ahash *tx_tfm_michael; + struct crypto_shash *tx_tfm_michael; /* scratch buffers for virt_to_page() (crypto API) */ u8 rx_hdr[16], tx_hdr[16]; @@ -106,8 +106,7 @@ static void *lib80211_tkip_init(int key_idx) goto fail; } - priv->tx_tfm_michael = crypto_alloc_ahash("michael_mic", 0, - CRYPTO_ALG_ASYNC); + priv->tx_tfm_michael = crypto_alloc_shash("michael_mic", 0, 0); if (IS_ERR(priv->tx_tfm_michael)) { priv->tx_tfm_michael = NULL; goto fail; @@ -120,8 +119,7 @@ static void *lib80211_tkip_init(int key_idx) goto fail; } - priv->rx_tfm_michael = crypto_alloc_ahash("michael_mic", 0, - CRYPTO_ALG_ASYNC); + priv->rx_tfm_michael = crypto_alloc_shash("michael_mic", 0, 0); if (IS_ERR(priv->rx_tfm_michael)) { priv->rx_tfm_michael = NULL; goto fail; @@ -131,9 +129,9 @@ static void *lib80211_tkip_init(int key_idx) fail: if (priv) { - crypto_free_ahash(priv->tx_tfm_michael); + crypto_free_shash(priv->tx_tfm_michael); crypto_free_skcipher(priv->tx_tfm_arc4); - crypto_free_ahash(priv->rx_tfm_michael); + crypto_free_shash(priv->rx_tfm_michael); crypto_free_skcipher(priv->rx_tfm_arc4); kfree(priv); } @@ -145,9 +143,9 @@ static void lib80211_tkip_deinit(void *priv) { struct lib80211_tkip_data *_priv = priv; if (_priv) { - crypto_free_ahash(_priv->tx_tfm_michael); + crypto_free_shash(_priv->tx_tfm_michael); crypto_free_skcipher(_priv->tx_tfm_arc4); - crypto_free_ahash(_priv->rx_tfm_michael); + crypto_free_shash(_priv->rx_tfm_michael); crypto_free_skcipher(_priv->rx_tfm_arc4); } kfree(priv); @@ -510,29 +508,36 @@ static int lib80211_tkip_decrypt(struct sk_buff *skb, int hdr_len, void *priv) return keyidx; } -static int michael_mic(struct crypto_ahash *tfm_michael, u8 * key, u8 * hdr, - u8 * data, size_t data_len, u8 * mic) +static int michael_mic(struct crypto_shash *tfm_michael, u8 *key, u8 *hdr, + u8 *data, size_t data_len, u8 *mic) { - AHASH_REQUEST_ON_STACK(req, tfm_michael); - struct scatterlist sg[2]; + SHASH_DESC_ON_STACK(desc, tfm_michael); int err; if (tfm_michael == NULL) { pr_warn("%s(): tfm_michael == NULL\n", __func__); return -1; } - sg_init_table(sg, 2); - sg_set_buf(&sg[0], hdr, 16); - sg_set_buf(&sg[1], data, data_len); - if (crypto_ahash_setkey(tfm_michael, key, 8)) + desc->tfm = tfm_michael; + desc->flags = 0; + + if (crypto_shash_setkey(tfm_michael, key, 8)) return -1; - ahash_request_set_tfm(req, tfm_michael); - ahash_request_set_callback(req, 0, NULL, NULL); - ahash_request_set_crypt(req, sg, mic, data_len + 16); - err = crypto_ahash_digest(req); - ahash_request_zero(req); + err = crypto_shash_init(desc); + if (err) + goto out; + err = crypto_shash_update(desc, hdr, 16); + if (err) + goto out; + err = crypto_shash_update(desc, data, data_len); + if (err) + goto out; + err = crypto_shash_final(desc, mic); + +out: + shash_desc_zero(desc); return err; } @@ -654,9 +659,9 @@ static int lib80211_tkip_set_key(void *key, int len, u8 * seq, void *priv) { struct lib80211_tkip_data *tkey = priv; int keyidx; - struct crypto_ahash *tfm = tkey->tx_tfm_michael; + struct crypto_shash *tfm = tkey->tx_tfm_michael; struct crypto_skcipher *tfm2 = tkey->tx_tfm_arc4; - struct crypto_ahash *tfm3 = tkey->rx_tfm_michael; + struct crypto_shash *tfm3 = tkey->rx_tfm_michael; struct crypto_skcipher *tfm4 = tkey->rx_tfm_arc4; keyidx = tkey->key_idx; -- 2.17.1 -- Kees Cook Pixel Security
