On Sun, Jul 15, 2018 at 08:59:12PM -0700, Kees Cook wrote: > 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> Reviewed-by: Eric Biggers <ebiggers@xxxxxxxxxx> > --- > drivers/md/dm-crypt.c | 31 ++++++++++++++----------------- > 1 file changed, 14 insertions(+), 17 deletions(-) > > diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c > index b61b069c33af..c4c922990090 100644 > --- a/drivers/md/dm-crypt.c > +++ b/drivers/md/dm-crypt.c > @@ -99,7 +99,7 @@ struct crypt_iv_operations { > }; > > struct iv_essiv_private { > - struct crypto_ahash *hash_tfm; > + struct crypto_shash *hash_tfm; > u8 *salt; > }; > > @@ -327,25 +327,22 @@ static int crypt_iv_plain64be_gen(struct crypt_config *cc, u8 *iv, > static int crypt_iv_essiv_init(struct crypt_config *cc) > { > struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv; > - AHASH_REQUEST_ON_STACK(req, essiv->hash_tfm); > - struct scatterlist sg; > + SHASH_DESC_ON_STACK(desc, essiv->hash_tfm); > struct crypto_cipher *essiv_tfm; > int err; > > - sg_init_one(&sg, cc->key, cc->key_size); > - ahash_request_set_tfm(req, essiv->hash_tfm); > - ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); > - ahash_request_set_crypt(req, &sg, essiv->salt, cc->key_size); > + desc->tfm = essiv->hash_tfm; > + desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; > > - err = crypto_ahash_digest(req); > - ahash_request_zero(req); > + err = crypto_shash_digest(desc, cc->key, cc->key_size, essiv->salt); > + shash_desc_zero(desc); > if (err) > return err; > > essiv_tfm = cc->iv_private; > > err = crypto_cipher_setkey(essiv_tfm, essiv->salt, > - crypto_ahash_digestsize(essiv->hash_tfm)); > + crypto_shash_digestsize(essiv->hash_tfm)); > if (err) > return err; > > @@ -356,7 +353,7 @@ static int crypt_iv_essiv_init(struct crypt_config *cc) > static int crypt_iv_essiv_wipe(struct crypt_config *cc) > { > struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv; > - unsigned salt_size = crypto_ahash_digestsize(essiv->hash_tfm); > + unsigned salt_size = crypto_shash_digestsize(essiv->hash_tfm); > struct crypto_cipher *essiv_tfm; > int r, err = 0; > > @@ -408,7 +405,7 @@ static void crypt_iv_essiv_dtr(struct crypt_config *cc) > struct crypto_cipher *essiv_tfm; > struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv; > > - crypto_free_ahash(essiv->hash_tfm); > + crypto_free_shash(essiv->hash_tfm); > essiv->hash_tfm = NULL; > > kzfree(essiv->salt); > @@ -426,7 +423,7 @@ static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti, > const char *opts) > { > struct crypto_cipher *essiv_tfm = NULL; > - struct crypto_ahash *hash_tfm = NULL; > + struct crypto_shash *hash_tfm = NULL; > u8 *salt = NULL; > int err; > > @@ -436,14 +433,14 @@ static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti, > } > > /* Allocate hash algorithm */ > - hash_tfm = crypto_alloc_ahash(opts, 0, CRYPTO_ALG_ASYNC); > + hash_tfm = crypto_alloc_shash(opts, 0, 0); > if (IS_ERR(hash_tfm)) { > ti->error = "Error initializing ESSIV hash"; > err = PTR_ERR(hash_tfm); > goto bad; > } > > - salt = kzalloc(crypto_ahash_digestsize(hash_tfm), GFP_KERNEL); > + salt = kzalloc(crypto_shash_digestsize(hash_tfm), GFP_KERNEL); > if (!salt) { > ti->error = "Error kmallocing salt storage in ESSIV"; > err = -ENOMEM; > @@ -454,7 +451,7 @@ static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti, > cc->iv_gen_private.essiv.hash_tfm = hash_tfm; > > essiv_tfm = alloc_essiv_cipher(cc, ti, salt, > - crypto_ahash_digestsize(hash_tfm)); > + crypto_shash_digestsize(hash_tfm)); > if (IS_ERR(essiv_tfm)) { > crypt_iv_essiv_dtr(cc); > return PTR_ERR(essiv_tfm); > @@ -465,7 +462,7 @@ static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti, > > bad: > if (hash_tfm && !IS_ERR(hash_tfm)) > - crypto_free_ahash(hash_tfm); > + crypto_free_shash(hash_tfm); > kfree(salt); > return err; > } > -- > 2.17.1 > > > -- > Kees Cook > Pixel Security -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
