From 359bbf709b67516325ac0615de7c206fab86c5cd 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 Signed-off-by: Marius Vlad (cherry-picked 761e05a702f5d537ffcc from git://people.freedesktop.org/~airlied/linux) --- 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 d8249b9f6cc4..b2ab53075de9 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: -- 2.17.1