[PATCH 08/12] drm: don't de-authenticate clients on master-close
David Herrmann
dh.herrmann at gmail.com
Wed Jul 23 08:26:43 PDT 2014
If an active DRM-Master closes its device, we deauthenticate all clients
on that master. However, if an inactive DRM-Master closes its device, we
do nothing. This is quite inconsistent and breaks several scenarios:
1) If this was used as security mechanism, it fails horribly if a master
closes a device while VT switched away. Furthermore, none of the few
drivers using ->master_*() callbacks seems to require it, anyway.
2) If you spawn weston (or any other non-UMS compositor) in background
while another compositor is active, both will get assigned to the
same "drm_master" object. If the foreground compositor now exits, all
clients of both the foreground AND background compositor will be
de-authenticated leading to unexpected behavior.
Stop this non-sense and keep clients authenticated. We don't do this when
dropping DRM-Master (i.e., switching VTs) so don't do it on active-close
either!
Signed-off-by: David Herrmann <dh.herrmann at gmail.com>
---
drivers/gpu/drm/drm_fops.c | 13 ++-----------
include/drm/drmP.h | 1 -
2 files changed, 2 insertions(+), 12 deletions(-)
diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
index f65087e..ff0a13f 100644
--- a/drivers/gpu/drm/drm_fops.c
+++ b/drivers/gpu/drm/drm_fops.c
@@ -252,8 +252,7 @@ static int drm_open_helper(struct file *filp, struct drm_minor *minor)
priv->minor = minor;
/* for compatibility root is always authenticated */
- priv->always_authenticated = capable(CAP_SYS_ADMIN);
- priv->authenticated = priv->always_authenticated;
+ priv->authenticated = capable(CAP_SYS_ADMIN);
priv->lock_count = 0;
INIT_LIST_HEAD(&priv->lhead);
@@ -453,20 +452,12 @@ int drm_release(struct inode *inode, struct file *filp)
if (drm_is_master(file_priv)) {
struct drm_master *master = file_priv->master;
- struct drm_file *temp;
-
- mutex_lock(&dev->struct_mutex);
- list_for_each_entry(temp, &dev->filelist, lhead) {
- if ((temp->master == file_priv->master) &&
- (temp != file_priv))
- temp->authenticated = temp->always_authenticated;
- }
/**
* Since the master is disappearing, so is the
* possibility to lock.
*/
-
+ mutex_lock(&dev->struct_mutex);
if (master->lock.hw_lock) {
if (dev->sigdata.lock == master->lock.hw_lock)
dev->sigdata.lock = NULL;
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index e1bb585..48d2fe7 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -385,7 +385,6 @@ struct drm_prime_file_private {
/** File private data */
struct drm_file {
- unsigned always_authenticated :1;
unsigned authenticated :1;
/* true when the client has asked us to expose stereo 3D mode flags */
unsigned stereo_allowed :1;
--
2.0.2
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