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 at linux.vnet.ibm.com>
---
security/integrity/ima/ima_crypto.c | 75 ++++++++++++++++++++++++++++++++++++-
1 file changed, 73 insertions(+), 2 deletions(-)
diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
index 8d86281..82c4d3c 100644
--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -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)
@@ -550,8 +607,8 @@ 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,
- struct ima_digest_data *hash)
+static int calc_buffer_shash(const void *buf, loff_t len,
+ struct ima_digest_data *hash)
{
struct crypto_shash *tfm;
int rc;
@@ -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)
--
2.1.0
