Re: [PATCH v4.19.x] make 'user_access_begin()' do 'access_ok()'
From: Greg KH
Date: Wed May 27 2020 - 11:31:43 EST
On Wed, May 13, 2020 at 05:08:19PM +0000, Ashwin H wrote:
> > Ok, but what does that mean for us?
> > You need to say why you are sending a patch, otherwise we will guess wrong.
> In drivers/gpu/drm/i915/i915_gem_execbuffer.c, ioctl functions does user_access_begin() without doing access_ok(Checks if a user space pointer is valid) first.
> A local attacker can craft a malicious ioctl function call to overwrite arbitrary kernel memory, resulting in a Denial of Service or privilege escalation (CVE-2018-20669)
> This patch makes sure that user_access_begin always does access_ok.
> user_access_begin has been modified to do access_ok internally.
I had this in the tree, but it broke the build on alpha, sh, and maybe a
few others :(
for the details.
Can you dig out all of the needed follow-on patches as well, and send
them all as a patch series for 4.19.y so that I can queue them all up at