wireless/lib80211: Convert from ahash to shash

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@mail.gmail.com

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Kees Cook 2018-07-15 20:52:26 -07:00 committed by Johannes Berg
parent 518ea3c54e
commit d17504b16e

View File

@ -65,9 +65,9 @@ struct lib80211_tkip_data {
int key_idx; int key_idx;
struct crypto_skcipher *rx_tfm_arc4; 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_skcipher *tx_tfm_arc4;
struct crypto_ahash *tx_tfm_michael; struct crypto_shash *tx_tfm_michael;
/* scratch buffers for virt_to_page() (crypto API) */ /* scratch buffers for virt_to_page() (crypto API) */
u8 rx_hdr[16], tx_hdr[16]; u8 rx_hdr[16], tx_hdr[16];
@ -106,8 +106,7 @@ static void *lib80211_tkip_init(int key_idx)
goto fail; goto fail;
} }
priv->tx_tfm_michael = crypto_alloc_ahash("michael_mic", 0, priv->tx_tfm_michael = crypto_alloc_shash("michael_mic", 0, 0);
CRYPTO_ALG_ASYNC);
if (IS_ERR(priv->tx_tfm_michael)) { if (IS_ERR(priv->tx_tfm_michael)) {
priv->tx_tfm_michael = NULL; priv->tx_tfm_michael = NULL;
goto fail; goto fail;
@ -120,8 +119,7 @@ static void *lib80211_tkip_init(int key_idx)
goto fail; goto fail;
} }
priv->rx_tfm_michael = crypto_alloc_ahash("michael_mic", 0, priv->rx_tfm_michael = crypto_alloc_shash("michael_mic", 0, 0);
CRYPTO_ALG_ASYNC);
if (IS_ERR(priv->rx_tfm_michael)) { if (IS_ERR(priv->rx_tfm_michael)) {
priv->rx_tfm_michael = NULL; priv->rx_tfm_michael = NULL;
goto fail; goto fail;
@ -131,9 +129,9 @@ static void *lib80211_tkip_init(int key_idx)
fail: fail:
if (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_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); crypto_free_skcipher(priv->rx_tfm_arc4);
kfree(priv); kfree(priv);
} }
@ -145,9 +143,9 @@ static void lib80211_tkip_deinit(void *priv)
{ {
struct lib80211_tkip_data *_priv = priv; struct lib80211_tkip_data *_priv = priv;
if (_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_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); crypto_free_skcipher(_priv->rx_tfm_arc4);
} }
kfree(priv); kfree(priv);
@ -510,29 +508,36 @@ static int lib80211_tkip_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
return keyidx; return keyidx;
} }
static int michael_mic(struct crypto_ahash *tfm_michael, u8 * key, u8 * hdr, static int michael_mic(struct crypto_shash *tfm_michael, u8 *key, u8 *hdr,
u8 * data, size_t data_len, u8 * mic) u8 *data, size_t data_len, u8 *mic)
{ {
AHASH_REQUEST_ON_STACK(req, tfm_michael); SHASH_DESC_ON_STACK(desc, tfm_michael);
struct scatterlist sg[2];
int err; int err;
if (tfm_michael == NULL) { if (tfm_michael == NULL) {
pr_warn("%s(): tfm_michael == NULL\n", __func__); pr_warn("%s(): tfm_michael == NULL\n", __func__);
return -1; 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; return -1;
ahash_request_set_tfm(req, tfm_michael); err = crypto_shash_init(desc);
ahash_request_set_callback(req, 0, NULL, NULL); if (err)
ahash_request_set_crypt(req, sg, mic, data_len + 16); goto out;
err = crypto_ahash_digest(req); err = crypto_shash_update(desc, hdr, 16);
ahash_request_zero(req); 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; 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; struct lib80211_tkip_data *tkey = priv;
int keyidx; 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_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; struct crypto_skcipher *tfm4 = tkey->rx_tfm_arc4;
keyidx = tkey->key_idx; keyidx = tkey->key_idx;