crypto: hash: in_buf should be constant

Hashing takes an input buffer, and writes the result in a separate
output buffer. Therefore, the input can be marked as constant, so that
constants can be supplied directly to the hashing context without any
intermediate copy, and without having to perform a type-unsafe cast
from (const uint8_t *) to (uint8_t *)

Signed-off-by: Titouan Christophe <[email protected]>

Author: titouanc

doc/releases/migration-guide-4.3.rst

@@ -334,6 +334,13 @@ Cellular
  * :c:enum:`cellular_access_technology` values have been redefined to align with 3GPP TS 27.007.
  * :c:enum:`cellular_registration_status` values have been extended to align with 3GPP TS 27.007.
 
+Crypto
+======
+
+* Hashing operations now require a constant input in the :c:struct:`hash_pkt`.
+  This shouldn't affect any existing code, unless an out-of-tree hashing backend actually
+  performs that operation in-place (see :github:`94218`)
+
 Flash Map
 =========
 

doc/releases/release-notes-4.3.rst

@@ -51,6 +51,10 @@ API Changes
 ..
   Only removed, deprecated and new APIs, changes go in migration guide.
 
+* Crypto
+
+  * The input buffer in :c:struct:`hash_pkt` is now constant
+
 Removed APIs and options
 ========================
 

include/zephyr/crypto/hash.h

@@ -88,7 +88,7 @@ struct hash_ctx {
 struct hash_pkt {
 
 	/** Start address of input buffer */
-	uint8_t *in_buf;
+	const uint8_t *in_buf;
 
 	/** Bytes to be operated upon */
 	size_t  in_len;