From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757254Ab2BCS3E (ORCPT ); Fri, 3 Feb 2012 13:29:04 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:59486 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756517Ab2BCS3A (ORCPT ); Fri, 3 Feb 2012 13:29:00 -0500 From: Stefan Bader To: Thomas Hellstrom Cc: Dave Airlie , Stefan Bader , linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [2.6.32+drm33-longterm] Patch "drm: Fix authentication kernel crash" has been added to staging queue Date: Fri, 3 Feb 2012 19:28:53 +0100 Message-Id: <1328293733-25890-1-git-send-email-stefan.bader@canonical.com> X-Mailer: git-send-email 1.7.5.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a note to let you know that I have just added a patch titled drm: Fix authentication kernel crash to the drm-next branch of the 2.6.32+drm33-longterm tree which can be found at http://git.kernel.org/?p=linux/kernel/git/smb/linux-2.6.32.y-drm33.z.git;a=shortlog;h=refs/heads/drm-next or http://kernel.ubuntu.com/git?p=smb/linux-2.6.32.y-drm33.z.git;a=shortlog;h=refs/heads/drm-next If you, or anyone else, feels it should not be added to the drm33-longterm tree, please reply to this email not later than 8 days after this email was sent. Thanks. -Stefan ------ >>From 26487be3d861e50dcfd4b19199e3c206d3700678 Mon Sep 17 00:00:00 2001 From: Thomas Hellstrom Date: Tue, 24 Jan 2012 18:54:21 +0100 Subject: [PATCH] drm: Fix authentication kernel crash commit 598781d71119827b454fd75d46f84755bca6f0c6 upstream. If the master tries to authenticate a client using drm_authmagic and that client has already closed its drm file descriptor, either wilfully or because it was terminated, the call to drm_authmagic will dereference a stale pointer into kmalloc'ed memory and corrupt it. Typically this results in a hard system hang. This patch fixes that problem by removing any authentication tokens (struct drm_magic_entry) open for a file descriptor when that file descriptor is closed. Signed-off-by: Thomas Hellstrom Reviewed-by: Daniel Vetter Signed-off-by: Dave Airlie Signed-off-by: Greg Kroah-Hartman Signed-off-by: Stefan Bader --- drivers/gpu/drm/drm_auth.c | 6 +++++- drivers/gpu/drm/drm_fops.c | 5 +++++ include/drm/drmP.h | 1 + 3 files changed, 11 insertions(+), 1 deletions(-) diff --git a/drivers/gpu/drm/drm_auth.c b/drivers/gpu/drm/drm_auth.c index 932b5aa..d676d49 100644 --- a/drivers/gpu/drm/drm_auth.c +++ b/drivers/gpu/drm/drm_auth.c @@ -102,7 +102,7 @@ static int drm_add_magic(struct drm_master *master, struct drm_file *priv, * Searches and unlinks the entry in drm_device::magiclist with the magic * number hash key, while holding the drm_device::struct_mutex lock. */ -static int drm_remove_magic(struct drm_master *master, drm_magic_t magic) +int drm_remove_magic(struct drm_master *master, drm_magic_t magic) { struct drm_magic_entry *pt; struct drm_hash_item *hash; @@ -137,6 +137,8 @@ static int drm_remove_magic(struct drm_master *master, drm_magic_t magic) * If there is a magic number in drm_file::magic then use it, otherwise * searches an unique non-zero magic number and add it associating it with \p * file_priv. + * This ioctl needs protection by the drm_global_mutex, which protects + * struct drm_file::magic and struct drm_magic_entry::priv. */ int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv) { @@ -174,6 +176,8 @@ int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv) * \return zero if authentication successed, or a negative number otherwise. * * Checks if \p file_priv is associated with the magic number passed in \arg. + * This ioctl needs protection by the drm_global_mutex, which protects + * struct drm_file::magic and struct drm_magic_entry::priv. */ int drm_authmagic(struct drm_device *dev, void *data, struct drm_file *file_priv) diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c index ba14553..519161e 100644 --- a/drivers/gpu/drm/drm_fops.c +++ b/drivers/gpu/drm/drm_fops.c @@ -449,6 +449,11 @@ int drm_release(struct inode *inode, struct file *filp) (long)old_encode_dev(file_priv->minor->device), dev->open_count); + /* Release any auth tokens that might point to this file_priv, + (do that under the drm_global_mutex) */ + if (file_priv->magic) + (void) drm_remove_magic(file_priv->master, file_priv->magic); + /* if the master has gone away we can't do anything with the lock */ if (file_priv->minor->master) drm_master_release(dev, filp); diff --git a/include/drm/drmP.h b/include/drm/drmP.h index 66713c6..ebab6a6 100644 --- a/include/drm/drmP.h +++ b/include/drm/drmP.h @@ -1221,6 +1221,7 @@ extern int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv); extern int drm_authmagic(struct drm_device *dev, void *data, struct drm_file *file_priv); +extern int drm_remove_magic(struct drm_master *master, drm_magic_t magic); /* Cache management (drm_cache.c) */ void drm_clflush_pages(struct page *pages[], unsigned long num_pages); -- 1.7.5.4