drm: stop information leak of old kernel stack.
commite72ac0859381d39b8647754f3b03eee878dd1c06
authorDave Airlie <airlied@redhat.com>
Tue, 17 Aug 2010 04:46:00 +0000 (17 14:46 +1000)
committerGreg Kroah-Hartman <gregkh@suse.de>
Thu, 26 Aug 2010 23:44:02 +0000 (26 16:44 -0700)
treeee95e55a200181bed467cd2f14dbc7872d950706
parent83573f5bcad91bd12ae3f7e8a429d8696c7dc663
drm: stop information leak of old kernel stack.

commit b9f0aee83335db1f3915f4e42a5e21b351740afd upstream.

non-critical issue, CVE-2010-2803

Userspace controls the amount of memory to be allocate, so it can
get the ioctl to allocate more memory than the kernel uses, and get
access to kernel stack. This can only be done for processes authenticated
to the X server for DRI access, and if the user has DRI access.

Fix is to just memset the data to 0 if the user doesn't copy into
it in the first place.

Reported-by: Kees Cook <kees@ubuntu.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/gpu/drm/drm_drv.c