@@ -246,7 +246,8 @@ static inline u32 crypto_requires_off(u32 type, u32 mask, u32 off)
* algorithm if any "inner" algorithm has them set. In some cases other flags
* are inherited too; these are just the flags that are *always* inherited.
*/
-#define CRYPTO_ALG_INHERITED_FLAGS CRYPTO_ALG_ASYNC
+#define CRYPTO_ALG_INHERITED_FLAGS \
+ (CRYPTO_ALG_ASYNC | CRYPTO_ALG_ALLOCATES_MEMORY)
/*
* Given the type and mask that specify the flags restrictions on a template
@@ -101,6 +101,38 @@
*/
#define CRYPTO_NOLOAD 0x00008000
+/*
+ * The algorithm may allocate memory during request processing, i.e. during
+ * encryption, decryption, or hashing. Users can request an algorithm with this
+ * flag unset if they can't handle memory allocation failures.
+ *
+ * This flag is currently only implemented for algorithms of type "skcipher",
+ * "aead", "ahash", "shash", and "cipher". Algorithms of other types might not
+ * have this flag set even if they allocate memory.
+ *
+ * In some edge cases, algorithms can allocate memory regardless of this flag.
+ * To avoid these cases, users must obey the following usage constraints:
+ * skcipher:
+ * - The IV buffer and all scatterlist elements must be aligned to the
+ * algorithm's alignmask.
+ * - If the data were to be divided into chunks of size
+ * crypto_skcipher_walksize() (with any remainder going at the end), no
+ * chunk can cross a page boundary or a scatterlist element boundary.
+ * aead:
+ * - The IV buffer and all scatterlist elements must be aligned to the
+ * algorithm's alignmask.
+ * - The first scatterlist element must contain all the associated data,
+ * and its pages must be !PageHighMem.
+ * - If the plaintext/ciphertext were to be divided into chunks of size
+ * crypto_aead_walksize() (with the remainder going at the end), no chunk
+ * can cross a page boundary or a scatterlist element boundary.
+ * ahash:
+ * - The result buffer must be aligned to the algorithm's alignmask.
+ * - crypto_ahash_finup() must not be used unless the algorithm implements
+ * ->finup() natively.
+ */
+#define CRYPTO_ALG_ALLOCATES_MEMORY 0x00010000
+
/*
* Transform masks and values (for crt_flags).
*/