drm/vmwgfx: limit the number of mip levels in vmw_gb_surface_define_ioctl()

commit ee9c4e681ec4f58e42a83cb0c22a0289ade1aacf upstream.

The 'req->mip_levels' parameter in vmw_gb_surface_define_ioctl() is
a user-controlled 'uint32_t' value which is used as a loop count limit.
This can lead to a kernel lockup and DoS. Add check for 'req->mip_levels'.

References:
https://bugzilla.redhat.com/show_bug.cgi?id=1437431

Signed-off-by: Vladis Dronov <vdronov@redhat.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
index c9c04ccccdd92489e94e9c050e33a8f5e70b689f..99b618ac2af6d7ec1ddf6b96b44d4840b6f05189 100644 (file)
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
@@ -1293,6 +1293,9 @@ int vmw_gb_surface_define_ioctl(struct drm_device *dev, void *data,
        if (req->multisample_count != 0)
                return -EINVAL;
 
+       if (req->mip_levels > DRM_VMW_MAX_MIP_LEVELS)
+               return -EINVAL;
+
        if (unlikely(vmw_user_surface_size == 0))
                vmw_user_surface_size = ttm_round_pot(sizeof(*user_srf)) +
                        128;