This is a note to let you know that I have just added a patch titled
drm: integer overflow in drm_mode_dirtyfb_ioctl()
to the drm-next branch of the 2.6.32+drm33-longterm tree which can be found at
http://git.kernel.org/?p=linux/kernel/git/smb/linux-2.6.32.y-drm33.z.git;a=shortlog;h=refs/heads/drm-next
or
http://kernel.ubuntu.com/git?p=smb/linux-2.6.32.y-drm33.z.git;a=shortlog;h=refs/heads/drm-next
If you, or anyone else, feels it should not be added to the drm33-longterm tree,
please reply to this email not later than 8 days after this email was sent.
Thanks.
-Stefan
------
>From a5cd335165e31db9dbab636fd29895d41da55dd2 Mon Sep 17 00:00:00 2001
From: Xi Wang <xi.w...@gmail.com>
Date: Wed, 23 Nov 2011 01:12:01 -0500
Subject: [PATCH] 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 <haogangc...@gmail.com>
Signed-off-by: Xi Wang <xi.w...@gmail.com>
Cc: sta...@kernel.org
Signed-off-by: Dave Airlie <airl...@redhat.com>
(cherry-picked from commit a5cd335165e31db9dbab636fd29895d41da55dd2 upstream)
Signed-off-by: Stefan Bader <stefan.ba...@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
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