tree 3328b6503f7852868f642263dfa8a3decc487a1e
parent 31ce4bfdfd10bf5db9bf85c92bbe0cf2edbdcad8
author Dave Airlie <airlied@redhat.com> 1282020360 +1000
committer Dave Airlie <airlied@redhat.com> 1282020705 +1000

drm: stop information leak of old kernel stack.

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>