This is a note to let you know that I have just added a patch titled

drm: Pad drm_mode_get_connector to 64-bit boundary

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree which can be found at:

http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linu...

If you, or anyone else, feels it should not be added to this tree, please reply to this email.

For more information about the 3.5.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks. -Luis

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From 81019eb6f5b7e60b588128f63e0bfaf34b650bcf Mon Sep 17 00:00:00 2001

From: Chris Wilson chris@chris-wilson.co.uk Date: Wed, 16 Oct 2013 09:49:02 +0100 Subject: drm: Pad drm_mode_get_connector to 64-bit boundary

commit bc5bd37ce48c66e9192ad2e7231e9678880f6f8e upstream.

Pavel Roskin reported that DRM_IOCTL_MODE_GETCONNECTOR was overwritting the 4 bytes beyond the end of its structure with a 32-bit userspace running on a 64-bit kernel. This is due to the padding gcc inserts as the drm_mode_get_connector struct includes a u64 and its size is not a natural multiple of u64s.

64-bit kernel:

sizeof(drm_mode_get_connector)=80, alignof=8 sizeof(drm_mode_get_encoder)=20, alignof=4 sizeof(drm_mode_modeinfo)=68, alignof=4

32-bit userspace:

sizeof(drm_mode_get_connector)=76, alignof=4 sizeof(drm_mode_get_encoder)=20, alignof=4 sizeof(drm_mode_modeinfo)=68, alignof=4

Fortuituously we can insert explicit padding to the tail of our structures without breaking ABI.

Reported-by: Pavel Roskin proski@gnu.org Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Dave Airlie airlied@redhat.com Cc: dri-devel@lists.freedesktop.org Signed-off-by: Dave Airlie airlied@redhat.com [ luis: backported to 3.5: - file rename: include/uapi/drm/drm_mode.h -> include/drm/drm_mode.h ] Signed-off-by: Luis Henriques luis.henriques@canonical.com --- include/drm/drm_mode.h | 2 ++ 1 file changed, 2 insertions(+)

diff --git a/include/drm/drm_mode.h b/include/drm/drm_mode.h index 3d6301b..f604a1a 100644 --- a/include/drm/drm_mode.h +++ b/include/drm/drm_mode.h @@ -223,6 +223,8 @@ struct drm_mode_get_connector { __u32 connection; __u32 mm_width, mm_height; /**< HxW in millimeters */ __u32 subpixel; + + __u32 pad; };

#define DRM_MODE_PROP_PENDING (1<<0) -- 1.8.3.2