Patchwork [maverick,maverick/ti-omap4,natty,natty/ti-omap4,CVE,1/1] drm: integer overflow in drm_mode_dirtyfb_ioctl()

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Submitter Andy Whitcroft
Date Jan. 18, 2012, 12:54 p.m.
Message ID <1326891254-9164-2-git-send-email-apw@canonical.com>
Download mbox | patch
Permalink /patch/136610/
State New
Headers show

Comments

Andy Whitcroft - Jan. 18, 2012, 12:54 p.m.
From: Xi Wang <xi.wang@gmail.com>

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)
CVE-2012-0044
BugLink: http://bugs.launchpad.net/bugs/917838
Signed-off-by: Andy Whitcroft <apw@canonical.com>
---
 drivers/gpu/drm/drm_crtc.c |    4 ++++
 include/drm/drm_mode.h     |    2 ++
 2 files changed, 6 insertions(+), 0 deletions(-)

Patch

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 5f32f72..0af9a64 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -1832,6 +1832,10 @@  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 c5ba163..9cf639c 100644
--- a/include/drm/drm_mode.h
+++ b/include/drm/drm_mode.h
@@ -232,6 +232,8 @@  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.
  *