drm: fix unsigned vs signed comparison issue in modeset ctl ioctl.

commit 1922756124ddd53846877416d92ba4a802bc658f upstream.

This fixes CVE-2011-1013.

Reported-by: Matthiew Herrb (OpenBSD X.org team)
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index 16d5155..d198884 100644 (file)
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -549,7 +549,8 @@ int drm_modeset_ctl(struct drm_device *dev, void *data,
                    struct drm_file *file_priv)
 {
        struct drm_modeset_ctl *modeset = data;
-       int crtc, ret = 0;
+       int ret = 0;
+       unsigned int crtc;
 
        /* If drm_vblank_init() hasn't been called yet, just no-op */
        if (!dev->num_crtcs)

diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index 274eaaa..4e53d77 100644 (file)
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -1022,7 +1022,7 @@ struct drm_device {
        struct platform_device *platformdev; /**< Platform device struture */
 
        struct drm_sg_mem *sg;  /**< Scatter gather memory */
-       int num_crtcs;                  /**< Number of CRTCs on this device */
+       unsigned int num_crtcs;                  /**< Number of CRTCs on this device */
        void *dev_private;              /**< device private data */
        void *mm_private;
        struct address_space *dev_mapping;