From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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, "David Herrmann" , "Dave Airlie" , "Zhaowei Yuan" Date: Tue, 08 Jul 2014 20:01:50 +0100 Message-ID: Subject: [PATCH 3.2 100/125] drm: fix NULL pointer access by wrong ioctl In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.2.61-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Zhaowei Yuan commit 1539fb9bd405ee32282ea0a38404f9e008ac5b7a upstream. If user uses wrong ioctl command with _IOC_NONE and argument size greater than 0, it can cause NULL pointer access from memset of line 463. If _IOC_NONE, don't memset to 0 for kdata. Signed-off-by: Zhaowei Yuan Reviewed-by: David Herrmann Signed-off-by: Dave Airlie [bwh: Backported to 3.2: adjust indentation] Signed-off-by: Ben Hutchings --- drivers/gpu/drm/drm_drv.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -456,8 +456,9 @@ long drm_ioctl(struct file *filp, retcode = -EFAULT; goto err_i1; } - } else + } else if (cmd & IOC_OUT) { memset(kdata, 0, usize); + } if (ioctl->flags & DRM_UNLOCKED) retcode = func(dev, kdata, file_priv);