From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757782Ab3KYOQI (ORCPT ); Mon, 25 Nov 2013 09:16:08 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:58994 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754313Ab3KYNxm (ORCPT ); Mon, 25 Nov 2013 08:53:42 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Chris Wilson" , "Pavel Roskin" , "Dave Airlie" , dri-devel@lists.freedesktop.org Date: Mon, 25 Nov 2013 13:44:29 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 75/87] drm: Pad drm_mode_get_connector to 64-bit boundary In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.212 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.53-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Chris Wilson 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 Signed-off-by: Chris Wilson Cc: Dave Airlie Cc: dri-devel@lists.freedesktop.org Signed-off-by: Dave Airlie [bwh: Backported to 3.2: adjust filename] Signed-off-by: Ben Hutchings --- include/uapi/drm/drm_mode.h | 2 ++ 1 file changed, 2 insertions(+) --- a/include/drm/drm_mode.h +++ b/include/drm/drm_mode.h @@ -184,6 +184,8 @@ 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)