On 04/05/2018 03:46 AM, Marcel Holtmann wrote:
By the way, what is you opinion on replacing crypto_shash_descsize(ctx) with
PAGE_SIZE / 8 in SHASH_DESC_ON_STACK?
Does it work for you?
isn’t that just waste?
Agree.
The macro itself is this.
#define SHASH_DESC_ON_STACK(shash, ctx) \
char __##shash##_desc[sizeof(struct shash_desc) + \
crypto_shash_descsize(ctx)] CRYPTO_MINALIGN_ATTR; \
struct shash_desc *shash = (struct shash_desc *)__##shash##_desc
For AES-CMAC, we could always do this with a manual macro that gives us the
right size. However that is error prone if any internals change. I think what
has to happened that crypto_shash_decsize becomes something the compiler can
evaluate at compile time.
Yeah. That would imply an analysis of the algorithm each of the callers
use. In the case of AES-CMAC, what is the maximum digest size?
I tried to find a fixed-length value for AES-CMAC but I didn't get any
output with git grep -n _DIGEST_SIZE | grep AES
Thanks
--
Gustavo
