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ima: calculate the hash of a buffer using aynchronous hash(ahash) 

Setting up ahash has some overhead.  Only use ahash to calculate the
hash of a buffer, if the buffer is larger than ima_ahash_minsize.

Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>
This commit is contained in:
Mimi Zohar 2015-12-28 11:56:09 -05:00
parent 11d7646df8
commit 98304bcf71
1 changed files with 73 additions and 2 deletions
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73
security/integrity/ima/ima_crypto.c
View File

@ -519,6 +519,63 @@ int ima_calc_field_array_hash(struct ima_field_data *field_data,
return rc;
}
static int calc_buffer_ahash_atfm(const void *buf, loff_t len,
struct ima_digest_data *hash,
struct crypto_ahash *tfm)
{
struct ahash_request *req;
struct scatterlist sg;
struct ahash_completion res;
int rc, ahash_rc = 0;
hash->length = crypto_ahash_digestsize(tfm);
req = ahash_request_alloc(tfm, GFP_KERNEL);
if (!req)
return -ENOMEM;
init_completion(&res.completion);
ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
CRYPTO_TFM_REQ_MAY_SLEEP,
ahash_complete, &res);
rc = ahash_wait(crypto_ahash_init(req), &res);
if (rc)
goto out;
sg_init_one(&sg, buf, len);
ahash_request_set_crypt(req, &sg, NULL, len);
ahash_rc = crypto_ahash_update(req);
/* wait for the update request to complete */
rc = ahash_wait(ahash_rc, &res);
if (!rc) {
ahash_request_set_crypt(req, NULL, hash->digest, 0);
rc = ahash_wait(crypto_ahash_final(req), &res);
}
out:
ahash_request_free(req);
return rc;
}
static int calc_buffer_ahash(const void *buf, loff_t len,
struct ima_digest_data *hash)
{
struct crypto_ahash *tfm;
int rc;
tfm = ima_alloc_atfm(hash->algo);
if (IS_ERR(tfm))
return PTR_ERR(tfm);
rc = calc_buffer_ahash_atfm(buf, len, hash, tfm);
ima_free_atfm(tfm);
return rc;
}
static int calc_buffer_shash_tfm(const void *buf, loff_t size,
struct ima_digest_data *hash,
struct crypto_shash *tfm)
@ -550,7 +607,7 @@ static int calc_buffer_shash_tfm(const void *buf, loff_t size,
return rc;
}
int ima_calc_buffer_hash(const void *buf, loff_t len,
static int calc_buffer_shash(const void *buf, loff_t len,
struct ima_digest_data *hash)
{
struct crypto_shash *tfm;
@ -566,6 +623,20 @@ int ima_calc_buffer_hash(const void *buf, loff_t len,
return rc;
}
int ima_calc_buffer_hash(const void *buf, loff_t len,
struct ima_digest_data *hash)
{
int rc;
if (ima_ahash_minsize && len >= ima_ahash_minsize) {
rc = calc_buffer_ahash(buf, len, hash);
if (!rc)
return 0;
}
return calc_buffer_shash(buf, len, hash);
}
static void __init ima_pcrread(int idx, u8 *pcr)
{
if (!ima_used_chip)