Patch "drm/vc4: Fix an integer overflow in temporary allocation layout." has been added to the 4.9-stable tree

Patch "drm/vc4: Fix an integer overflow in temporary allocation layout." has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    drm/vc4: Fix an integer overflow in temporary allocation layout.

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-vc4-fix-an-integer-overflow-in-temporary-allocation-layout.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 0f2ff82e11c86c05d051cae32b58226392d33bbf Mon Sep 17 00:00:00 2001
From: Eric Anholt <eric@anholt.net>
Date: Tue, 17 Jan 2017 21:42:53 +1100
Subject: drm/vc4: Fix an integer overflow in temporary allocation layout.

From: Eric Anholt <eric@anholt.net>

commit 0f2ff82e11c86c05d051cae32b58226392d33bbf upstream.

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.")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/vc4/vc4_gem.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/vc4/vc4_gem.c
+++ b/drivers/gpu/drm/vc4/vc4_gem.c
@@ -594,7 +594,8 @@ vc4_get_bcl(struct drm_device *dev, stru
 					  args->shader_rec_count);
 	struct vc4_bo *bo;
 
-	if (uniforms_offset < shader_rec_offset ||
+	if (shader_rec_offset < args->bin_cl_size ||
+	    uniforms_offset < shader_rec_offset ||
 	    exec_size < uniforms_offset ||
 	    args->shader_rec_count >= (UINT_MAX /
 					  sizeof(struct vc4_shader_state)) ||


Patches currently in stable-queue which might be from eric@anholt.net are

queue-4.9/drm-vc4-return-einval-on-the-overflow-checks-failing.patch
queue-4.9/drm-vc4-fix-memory-leak-of-the-crtc-state.patch
queue-4.9/drm-vc4-fix-an-integer-overflow-in-temporary-allocation-layout.patch
queue-4.9/drm-vc4-fix-a-bounds-check.patch