diff options
Diffstat (limited to 'include/linux/crypto.h')
| -rw-r--r-- | include/linux/crypto.h | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/include/linux/crypto.h b/include/linux/crypto.h index f73f0b51e1cd..ef90e07c9635 100644 --- a/include/linux/crypto.h +++ b/include/linux/crypto.h @@ -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). */ #define CRYPTO_TFM_NEED_KEY 0x00000001 |