tree 6e3997847bd92871d1ee00916fcd04d59f19126a
parent 383203eff718d7397ffc68ac6c3ed644d3017fc7
author Tycho Andersen <tycho@tycho.ws> 1524601599 -0600
committer James Morris <james.morris@microsoft.com> 1526069269 -0700

dh key: get rid of stack allocated array for zeroes

We're interested in getting rid of all of the stack allocated arrays in
the kernel: https://lkml.org/lkml/2018/3/7/621

This case is interesting, since we really just need an array of bytes that
are zero. The loop already ensures that if the array isn't exactly the
right size that enough zero bytes will be copied in. So, instead of
choosing this value to be the size of the hash, let's just choose it to be
32, since that is a common size, is not too big, and will not result in too
many extra iterations of the loop.

v2: split out from other patch, just hardcode array size instead of
    dynamically allocating something the right size
v3: fix typo of 256 -> 32

Signed-off-by: Tycho Andersen <tycho@tycho.ws>
Reviewed-by: Kees Cook <keescook@chromium.org>
CC: David Howells <dhowells@redhat.com>
CC: James Morris <jmorris@namei.org>
CC: "Serge E. Hallyn" <serge@hallyn.com>
CC: Eric Biggers <ebiggers3@gmail.com>
Signed-off-by: James Morris <james.morris@microsoft.com>