Patchwork [lucid,CVE-2012-0044] drm: integer overflow in drm_mode_dirtyfb_ioctl()

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Submitter Steve Conklin
Date Aug. 8, 2012, 8:24 p.m.
Message ID <1344457440-23625-1-git-send-email-sconklin@canonical.com>
Download mbox | patch
Permalink /patch/175953/
State New
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Steve Conklin - Aug. 8, 2012, 8:24 p.m.
From: Xi Wang <xi.wang@gmail.com>

CVE-2012-0044

BugLink: http://bugs.launchpad.net/bugs/917838

There is a potential integer overflow in drm_mode_dirtyfb_ioctl()
if userspace passes in a large num_clips.  The call to kmalloc would
allocate a small buffer, and the call to fb->funcs->dirty may result
in a memory corruption.

Reported-by: Haogang Chen <haogangchen@gmail.com>
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
(cherry picked from commit a5cd335165e31db9dbab636fd29895d41da55dd2)
Signed-off-by: Steve Conklin <sconklin@canonical.com>
---
 drivers/gpu/drm/drm_crtc.c |    4 ++++
 include/drm/drm_mode.h     |    2 ++
 2 files changed, 6 insertions(+)
Herton Ronaldo Krzesinski - Aug. 8, 2012, 9:40 p.m.

Andy Whitcroft - Aug. 9, 2012, 8:58 a.m.
On Wed, Aug 08, 2012 at 03:24:00PM -0500, Steve Conklin wrote:
> From: Xi Wang <xi.wang@gmail.com>
> 
> CVE-2012-0044
> 
> BugLink: http://bugs.launchpad.net/bugs/917838
> 
> There is a potential integer overflow in drm_mode_dirtyfb_ioctl()
> if userspace passes in a large num_clips.  The call to kmalloc would
> allocate a small buffer, and the call to fb->funcs->dirty may result
> in a memory corruption.
> 
> Reported-by: Haogang Chen <haogangchen@gmail.com>
> Signed-off-by: Xi Wang <xi.wang@gmail.com>
> Cc: stable@kernel.org
> Signed-off-by: Dave Airlie <airlied@redhat.com>
> (cherry picked from commit a5cd335165e31db9dbab636fd29895d41da55dd2)
> Signed-off-by: Steve Conklin <sconklin@canonical.com>
> ---
>  drivers/gpu/drm/drm_crtc.c |    4 ++++
>  include/drm/drm_mode.h     |    2 ++
>  2 files changed, 6 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> index 405c63b..8323fc3 100644
> --- a/drivers/gpu/drm/drm_crtc.c
> +++ b/drivers/gpu/drm/drm_crtc.c
> @@ -1873,6 +1873,10 @@ int drm_mode_dirtyfb_ioctl(struct drm_device *dev,
>  	}
>  
>  	if (num_clips && clips_ptr) {
> +		if (num_clips < 0 || num_clips > DRM_MODE_FB_DIRTY_MAX_CLIPS) {
> +			ret = -EINVAL;
> +			goto out_err1;
> +		}
>  		clips = kzalloc(num_clips * sizeof(*clips), GFP_KERNEL);
>  		if (!clips) {
>  			ret = -ENOMEM;
> diff --git a/include/drm/drm_mode.h b/include/drm/drm_mode.h
> index d30bedf..ddd46db 100644
> --- a/include/drm/drm_mode.h
> +++ b/include/drm/drm_mode.h
> @@ -235,6 +235,8 @@ struct drm_mode_fb_cmd {
>  #define DRM_MODE_FB_DIRTY_ANNOTATE_FILL 0x02
>  #define DRM_MODE_FB_DIRTY_FLAGS         0x03
>  
> +#define DRM_MODE_FB_DIRTY_MAX_CLIPS     256
> +
>  /*
>   * Mark a region of a framebuffer as dirty.
>   *
> -- 
> 1.7.9.5

Acked-by: Andy Whitcroft <apw@canonical.com>

-apw
Andy Whitcroft - Aug. 9, 2012, 9:05 a.m.
Applied to Lucid.

-apw

Patch

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 405c63b..8323fc3 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -1873,6 +1873,10 @@  int drm_mode_dirtyfb_ioctl(struct drm_device *dev,
 	}
 
 	if (num_clips && clips_ptr) {
+		if (num_clips < 0 || num_clips > DRM_MODE_FB_DIRTY_MAX_CLIPS) {
+			ret = -EINVAL;
+			goto out_err1;
+		}
 		clips = kzalloc(num_clips * sizeof(*clips), GFP_KERNEL);
 		if (!clips) {
 			ret = -ENOMEM;
diff --git a/include/drm/drm_mode.h b/include/drm/drm_mode.h
index d30bedf..ddd46db 100644
--- a/include/drm/drm_mode.h
+++ b/include/drm/drm_mode.h
@@ -235,6 +235,8 @@  struct drm_mode_fb_cmd {
 #define DRM_MODE_FB_DIRTY_ANNOTATE_FILL 0x02
 #define DRM_MODE_FB_DIRTY_FLAGS         0x03
 
+#define DRM_MODE_FB_DIRTY_MAX_CLIPS     256
+
 /*
  * Mark a region of a framebuffer as dirty.
  *