From 761e05a702f5d537ffcca1ba933f9f0a968aa022 Mon Sep 17 00:00:00 2001 From: Keith Packard Date: Thu, 18 Jan 2018 17:51:59 -0800 Subject: [PATCH] drm: Check for lessee in DROP_MASTER ioctl Don't let a lessee control what the current DRM master is set to; that's the job of the "real" master. Otherwise, the lessee would disable all access to master operations for the owner and all lessees under it. This matches the same check made in the SET_MASTER ioctl. Signed-off-by: Keith Packard Fixes: 2ed077e467ee ("drm: Add drm_object lease infrastructure [v5]") Cc: # v4.15+ Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20180119015159.1606-1-keithp@keithp.com --- drivers/gpu/drm/drm_auth.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/gpu/drm/drm_auth.c b/drivers/gpu/drm/drm_auth.c index aad468d170a7..d9c0f7573905 100644 --- a/drivers/gpu/drm/drm_auth.c +++ b/drivers/gpu/drm/drm_auth.c @@ -230,6 +230,12 @@ int drm_dropmaster_ioctl(struct drm_device *dev, void *data, if (!dev->master) goto out_unlock; + if (file_priv->master->lessor != NULL) { + DRM_DEBUG_LEASE("Attempt to drop lessee %d as master\n", file_priv->master->lessee_id); + ret = -EINVAL; + goto out_unlock; + } + ret = 0; drm_drop_master(dev, file_priv); out_unlock: -- 2.30.2