Re: [PATCH] ppp: mppe: Remove VLA usage

On Mon, Jul 16, 2018 at 6:05 AM, Kees Cook [off-list ref] wrote:

In the quest to remove all stack VLA usage from the kernel[1], this
removes the discouraged use of AHASH_REQUEST_ON_STACK (and associated
VLA) by switching to shash directly and keeping the associated descriptor
allocated with the regular state on the heap.

[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com

Signed-off-by: Kees Cook <redacted>

I had concerns at first that this approach might make it slower, but
upon reading through implementation of the shash_ahash_ implementation,
I concluded that it can only be better than before, improving both
performance and stack usage.

Acked-by: Arnd Bergmann <arnd@arndb.de>