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drm: integer overflow in drm_mode_dirtyfb_ioctl()

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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>
This commit is contained in:
Xi Wang
2011-11-23 01:12:01 -05:00
committed by Dave Airlie
parent c916874d60
commit a5cd335165
2 changed files with 6 additions and 0 deletions
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4
drivers/gpu/drm/drm_crtc.c
View File

@@ -1873,6 +1873,10 @@ int drm_mode_dirtyfb_ioctl(struct drm_device *dev,
} }
if (num_clips && clips_ptr) { 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); clips = kzalloc(num_clips * sizeof(*clips), GFP_KERNEL);
if (!clips) { if (!clips) {
ret = -ENOMEM; ret = -ENOMEM;

2
include/drm/drm_mode.h
View File

@@ -235,6 +235,8 @@ struct drm_mode_fb_cmd {
#define DRM_MODE_FB_DIRTY_ANNOTATE_FILL 0x02 #define DRM_MODE_FB_DIRTY_ANNOTATE_FILL 0x02
#define DRM_MODE_FB_DIRTY_FLAGS 0x03 #define DRM_MODE_FB_DIRTY_FLAGS 0x03
#define DRM_MODE_FB_DIRTY_MAX_CLIPS 256
/* /*
* Mark a region of a framebuffer as dirty. * Mark a region of a framebuffer as dirty.
* *