drm/vc4: Fix an integer overflow in temporary allocation layout.
authorEric Anholt <eric@anholt.net>
Tue, 17 Jan 2017 10:42:53 +0000 (21:42 +1100)
committerEric Anholt <eric@anholt.net>
Tue, 17 Jan 2017 11:05:55 +0000 (22:05 +1100)
commit0f2ff82e11c86c05d051cae32b58226392d33bbf
treea902de69d6b8d2aacae17a8549bffe959037d0e2
parent21ccc32496b2f63228f5232b3ac0e426e8fb3c31
drm/vc4: Fix an integer overflow in temporary allocation layout.

We copy the unvalidated ioctl arguments from the user into kernel
temporary memory to run the validation from, to avoid a race where the
user updates the unvalidate contents in between validating them and
copying them into the validated BO.

However, in setting up the layout of the kernel side, we failed to
check one of the additions (the roundup() for shader_rec_offset)
against integer overflow, allowing a nearly MAX_UINT value of
bin_cl_size to cause us to under-allocate the temporary space that we
then copy_from_user into.

Reported-by: Murray McAllister <murray.mcallister@insomniasec.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Fixes: d5b1a78a772f ("drm/vc4: Add support for drawing 3D frames.")
drivers/gpu/drm/vc4/vc4_gem.c