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Subject[PATCH v2] crypto: hash.h: Prevent use of req->result in ahash update
Date
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>
---
version 2:
Change req->digest to req->result, as pointed out by Tom Lendacky

include/crypto/hash.h | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/include/crypto/hash.h b/include/crypto/hash.h
index 2d1849dffb80..76e432cab75d 100644
--- 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 {
--
2.16.2
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