drm: integer overflow in drm_mode_dirtyfb_ioctl()
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>
CVE-2012-0044
(cherry-picked from commit a5cd335165e31db9dbab636fd29895d41da55dd2 upstream)
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 81ba0e6..ec9e97e 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -1832,6 +1832,10 @@
}
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 c5ba163..9cf639c 100644
--- a/include/drm/drm_mode.h
+++ b/include/drm/drm_mode.h
@@ -232,6 +232,8 @@
#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.
*
