crypto: hash - Prevent use of req->result in ahash update

Prevent improper use of req->result field in ahash update, init, export and
import functions in drivers code. A driver should use ahash request context
if it needs to save internal state.

Signed-off-by: Kamil Konieczny <k.konieczny@partner.samsung.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/include/crypto/hash.h b/include/crypto/hash.h
index 2d1849dffb807ec1806cbc2f86a8f6d42a53a9c7..76e432cab75dbc65e37b4804e6746a4108a8fb75 100644 (file)
--- a/include/crypto/hash.h
+++ b/include/crypto/hash.h
@@ -74,7 +74,8 @@ struct ahash_request {
  * @init: **[mandatory]** Initialize the transformation context. Intended only to initialize the
  *       state of the HASH transformation at the beginning. This shall fill in
  *       the internal structures used during the entire duration of the whole
- *       transformation. No data processing happens at this point.
+ *       transformation. No data processing happens at this point. Driver code
+ *       implementation must not use req->result.
  * @update: **[mandatory]** Push a chunk of data into the driver for transformation. This
  *        function actually pushes blocks of data from upper layers into the
  *        driver, which then passes those to the hardware as seen fit. This
@@ -83,7 +84,8 @@ struct ahash_request {
  *        transformation. This function shall not modify the transformation
  *        context, as this function may be called in parallel with the same
  *        transformation object. Data processing can happen synchronously
- *        [SHASH] or asynchronously [AHASH] at this point.
+ *        [SHASH] or asynchronously [AHASH] at this point. Driver must not use
+ *        req->result.
  * @final: **[mandatory]** Retrieve result from the driver. This function finalizes the
  *        transformation and retrieves the resulting hash from the driver and
  *        pushes it back to upper layers. No data processing happens at this
@@ -120,11 +122,12 @@ struct ahash_request {
  *         you want to save partial result of the transformation after
  *         processing certain amount of data and reload this partial result
  *         multiple times later on for multiple re-use. No data processing
- *         happens at this point.
+ *         happens at this point. Driver must not use req->result.
  * @import: Import partial state of the transformation. This function loads the
  *         entire state of the ongoing transformation from a provided block of
  *         data so the transformation can continue from this point onward. No
- *         data processing happens at this point.
+ *         data processing happens at this point. Driver must not use
+ *         req->result.
  * @halg: see struct hash_alg_common
  */
 struct ahash_alg {