Re: [RESEND] SHASH_DESC_ON_STACK macro

[Gustavo A. R. Silva]

Hi Herbert,

On 03/27/2018 05:07 AM, Herbert Xu wrote:

On Fri, Mar 23, 2018 at 02:09:46PM -0500, Gustavo A. R. Silva wrote:

Hi Herbert,

There is an ongoing effort to remove all VLAs from the code base [1] and
while working on that I came across the following macro at
include/crypto/hash.h:154:

#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


Currently, this macro is being used in 46 different places.

I wonder how big can tfm->descsize can get?

descsize is capped at PAGE_SIZE / 8.

Sorry for the late response. It seems I lost track of this email somehow.

OK. So based on your response I will propose a patch for this.

Thanks!
--
Gustavo