From: Li Qiang Date: Tue, 28 Mar 2017 03:10:53 +0000 (-0700) Subject: drm/vmwgfx: fix integer overflow in vmw_surface_define_ioctl() X-Git-Tag: release-20171130_firefly~4^2~100^2~1^2~15^2~27 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=c21636bd64c511160846bdf87ef4c7ff48680c99;p=firefly-linux-kernel-4.4.55.git drm/vmwgfx: fix integer overflow in vmw_surface_define_ioctl() commit e7e11f99564222d82f0ce84bd521e57d78a6b678 upstream. In vmw_surface_define_ioctl(), the 'num_sizes' is the sum of the 'req->mip_levels' array. This array can be assigned any value from the user space. As both the 'num_sizes' and the array is uint32_t, it is easy to make 'num_sizes' overflow. The later 'mip_levels' is used as the loop count. This can lead an oob write. Add the check of 'req->mip_levels' to avoid this. Signed-off-by: Li Qiang Reviewed-by: Thomas Hellstrom Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c index 79f78a68d92d..c9c04ccccdd9 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c @@ -715,8 +715,11 @@ int vmw_surface_define_ioctl(struct drm_device *dev, void *data, 128; num_sizes = 0; - for (i = 0; i < DRM_VMW_MAX_SURFACE_FACES; ++i) + for (i = 0; i < DRM_VMW_MAX_SURFACE_FACES; ++i) { + if (req->mip_levels[i] > DRM_VMW_MAX_MIP_LEVELS) + return -EINVAL; num_sizes += req->mip_levels[i]; + } if (num_sizes > DRM_VMW_MAX_SURFACE_FACES * DRM_VMW_MAX_MIP_LEVELS || num_sizes == 0)