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wireless/lib80211: Convert from ahash to shash

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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
1 changed files with 30 additions and 25 deletions
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55
net/wireless/lib80211_crypt_tkip.c
View file

@ -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;