Correctly set the length of the drm_event to the size of the structure that's actually used.
The length of the drm_event was set to the parent structure instead of to the drm_vmw_event_fence which is supposed to be read. drm_read uses the length parameter to copy the event to the user space thus resuling in oob reads.
Signed-off-by: Zack Rusin zack.rusin@broadcom.com Fixes: 8b7de6aa8468 ("vmwgfx: Rework fence event action") Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-23566 Cc: David Airlie airlied@gmail.com CC: Daniel Vetter daniel@ffwll.ch Cc: Zack Rusin zack.rusin@broadcom.com Cc: Broadcom internal kernel review list bcm-kernel-feedback-list@broadcom.com Cc: dri-devel@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org # v3.4+ --- drivers/gpu/drm/vmwgfx/vmwgfx_fence.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c index 2a0cda324703..5efc6a766f64 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c @@ -991,7 +991,7 @@ static int vmw_event_fence_action_create(struct drm_file *file_priv, }
event->event.base.type = DRM_VMW_EVENT_FENCE_SIGNALED; - event->event.base.length = sizeof(*event); + event->event.base.length = sizeof(event->event); event->event.user_data = user_data;
ret = drm_event_reserve_init(dev, file_priv, &event->base, &event->event.base);