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dm crypt: restructure essiv error path

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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: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Milan Broz 2009-12-10 23:51:56 +00:00 committed by Alasdair G Kergon
parent 6047359277
commit 5861f1be00
1 changed files with 26 additions and 20 deletions
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46
drivers/md/dm-crypt.c
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@ -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)