[102/151] dm crypt: restructure essiv error path

Greg KH
2009-12-17T04:24:20Z

From: Milan Broz <mbroz@redhat.com>

commit 5861f1be00b3b70f8ab5e5a81392a6cf69666cd2 upstream.

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.

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/md/dm-crypt.c | 46 ++++++++++++++++++++++++++--------------------
1 file changed, 26 insertions(+), 20 deletions(-)

--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -187,15 +187,15 @@ static void crypt_iv_essiv_dtr(struct cr
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 cry
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 cry
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)