Messages in this thread Patch in this message |  | | Date | Wed, 07 Dec 2011 08:06:25 -0800 | | From | Greg KH <> | | Subject | [05/80] drm: integer overflow in drm_mode_dirtyfb_ioctl() |
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3.0-stable review patch. If anyone has any objections, please let me know.
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From: Xi Wang <xi.wang@gmail.com>
commit a5cd335165e31db9dbab636fd29895d41da55dd2 upstream.
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> Signed-off-by: Dave Airlie <airlied@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- drivers/gpu/drm/drm_crtc.c | 4 ++++ include/drm/drm_mode.h | 2 ++ 2 files changed, 6 insertions(+)
--- a/drivers/gpu/drm/drm_crtc.c +++ b/drivers/gpu/drm/drm_crtc.c @@ -1866,6 +1866,10 @@ int drm_mode_dirtyfb_ioctl(struct drm_de } 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; --- a/include/drm/drm_mode.h +++ b/include/drm/drm_mode.h @@ -233,6 +233,8 @@ 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. *
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