From bc5bd37ce48c66e9192ad2e7231e9678880f6f8e Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Wed, 16 Oct 2013 09:49:02 +0100 Subject: [PATCH] drm: Pad drm_mode_get_connector to 64-bit boundary 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 Signed-off-by: Chris Wilson Cc: Dave Airlie Cc: dri-devel@lists.freedesktop.org Cc: stable@vger.kernel.org Signed-off-by: Dave Airlie --- include/uapi/drm/drm_mode.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h index 550811712f78..28acbaf4a81e 100644 --- a/include/uapi/drm/drm_mode.h +++ b/include/uapi/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) -- 2.39.5