Re: [PATCH] lib/crypto: aes-cmac: Hide selection mask value from compilers

[Eric Biggers <ebiggers@kernel.org>]

On Fri, Oct 30, 2026 at 10:20:53PM -0700, Eric Biggers wrote:
> Hide selection mask values from compilers, so that they cannot see that
> they are used to select between two values and potentially generate a
> secret-dependent branch.  This is not known to be happening here, but we
> might as well be extra careful.
> 
> Since the selected values are only 0x87 and 0 here, change the type of
> the mask to 'unsigned long' so that the compiler is not forced to
> materialize it in a register pair on 32-bit architectures.
> 
> Signed-off-by: Eric Biggers <ebiggers@kernel.org>
> ---
>  lib/crypto/aes.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)

Applied to https://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux.git/log/?h=libcrypto-next

- Eric