Commit 5861f1be authored by Milan Broz's avatar Milan Broz Committed by Alasdair G Kergon
Browse files

dm crypt: restructure essiv error path 



Use kzfree for salt deallocation because it is derived from the volume
key.  Use a common error path in ESSIV constructor.

Required by a later patch which fixes the way key material is wiped
from memory.

Cc: stable@kernel.org
Signed-off-by: default avatarMilan Broz <mbroz@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent 60473592

drivers/md/dm-crypt.c

+26 −20
Original line number Diff line number Diff line
@@ -187,15 +187,15 @@ static void crypt_iv_essiv_dtr(struct crypt_config *cc) 
static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,

			      const char *opts)

{

	struct crypto_cipher *essiv_tfm;

	struct crypto_hash *hash_tfm;

	struct crypto_cipher *essiv_tfm = NULL;

	struct crypto_hash *hash_tfm = NULL;

	struct hash_desc desc;

	struct scatterlist sg;

	unsigned int saltsize;

	u8 *salt;

	u8 *salt = NULL;

	int err;



	if (opts == NULL) {

	if (!opts) {

		ti->error = "Digest algorithm missing for ESSIV mode";

		return -EINVAL;

	}
@@ -204,15 +204,16 @@ static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti, 
	hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC);

	if (IS_ERR(hash_tfm)) {

		ti->error = "Error initializing ESSIV hash";

		return PTR_ERR(hash_tfm);

		err = PTR_ERR(hash_tfm);

		goto bad;

	}



	saltsize = crypto_hash_digestsize(hash_tfm);

	salt = kmalloc(saltsize, GFP_KERNEL);

	if (salt == NULL) {

	salt = kzalloc(saltsize, GFP_KERNEL);

	if (!salt) {

		ti->error = "Error kmallocing salt storage in ESSIV";

		crypto_free_hash(hash_tfm);

		return -ENOMEM;

		err = -ENOMEM;

		goto bad;

	}



	sg_init_one(&sg, cc->key, cc->key_size);
@@ -220,39 +221,44 @@ static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti, 
	desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;

	err = crypto_hash_digest(&desc, &sg, cc->key_size, salt);

	crypto_free_hash(hash_tfm);

	hash_tfm = NULL;



	if (err) {

		ti->error = "Error calculating hash in ESSIV";

		kfree(salt);

		return err;

		goto bad;

	}



	/* Setup the essiv_tfm with the given salt */

	essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);

	if (IS_ERR(essiv_tfm)) {

		ti->error = "Error allocating crypto tfm for ESSIV";

		kfree(salt);

		return PTR_ERR(essiv_tfm);

		err = PTR_ERR(essiv_tfm);

		goto bad;

	}

	if (crypto_cipher_blocksize(essiv_tfm) !=

	    crypto_ablkcipher_ivsize(cc->tfm)) {

		ti->error = "Block size of ESSIV cipher does "

			    "not match IV size of block cipher";

		crypto_free_cipher(essiv_tfm);

		kfree(salt);

		return -EINVAL;

		err = -EINVAL;

		goto bad;

	}

	err = crypto_cipher_setkey(essiv_tfm, salt, saltsize);

	if (err) {

		ti->error = "Failed to set key for ESSIV cipher";

		crypto_free_cipher(essiv_tfm);

		kfree(salt);

		return err;

		goto bad;

	}

	kfree(salt);

	kzfree(salt);



	cc->iv_gen_private.essiv.tfm = essiv_tfm;

	return 0;



bad:

	if (essiv_tfm && !IS_ERR(essiv_tfm))

		crypto_free_cipher(essiv_tfm);

	if (hash_tfm && !IS_ERR(hash_tfm))

		crypto_free_hash(hash_tfm);

	kzfree(salt);

	return err;

}



static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, sector_t sector)