[PATCH 4/5] drm: Check mode object lease status in all master ioctl paths [v2]

From: Keith Packard <keithp@keithp.com>
To: linux-kernel@vger.kernel.org, Dave Airlie <airlied@redhat.com>,
	Daniel Vetter <daniel@ffwll.ch>
Cc: Keith Packard <keithp@keithp.com>, dri-devel@lists.freedesktop.org
Subject: [PATCH 4/5] drm: Check mode object lease status in all master ioctl paths [v2]
Date: Fri, 28 Apr 2017 23:07:01 -0700	[thread overview]
Message-ID: <20170429060702.6656-5-keithp@keithp.com> (raw)
In-Reply-To: <20170429060702.6656-1-keithp@keithp.com>

Attempts to modify un-leased objects are rejected with an error.
Information returned about unleased objects is modified to make them
appear unusable and/or disconnected.

Changes for v2 as suggested by Daniel Vetter <daniel.vetter@ffwll.ch>:

With the change in the __drm_mode_object_find API to pass the
file_priv along, we can now centralize most of the lease-based access
checks in that function.

A few places skip that API and require in-line checks.

Signed-off-by: Keith Packard <keithp@keithp.com>
---
 drivers/gpu/drm/drm_auth.c        |  2 +-
 drivers/gpu/drm/drm_connector.c   |  8 +++---
 drivers/gpu/drm/drm_encoder.c     |  8 +++---
 drivers/gpu/drm/drm_mode_config.c | 52 ++++++++++++++++++++++++---------------
 drivers/gpu/drm/drm_mode_object.c | 22 +++++++++++++++++
 drivers/gpu/drm/drm_plane.c       |  6 +++--
 6 files changed, 69 insertions(+), 29 deletions(-)

diff --git a/drivers/gpu/drm/drm_auth.c b/drivers/gpu/drm/drm_auth.c
index 1db4f63860d1..44c99d12f4c1 100644
--- a/drivers/gpu/drm/drm_auth.c
+++ b/drivers/gpu/drm/drm_auth.c
@@ -303,7 +303,7 @@ void drm_master_release(struct drm_file *file_priv)
  */
 bool drm_is_current_master(struct drm_file *fpriv)
 {
-	return fpriv->is_master && fpriv->master == fpriv->minor->dev->master;
+	return fpriv->is_master && drm_lease_owner(fpriv->master) == fpriv->minor->dev->master;
 }
 EXPORT_SYMBOL(drm_is_current_master);
 
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 670c20d5660c..dbf34f08363b 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -1094,7 +1094,8 @@ int drm_mode_getconnector(struct drm_device *dev, void *data,
 	}
 
 	for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++)
-		if (connector->encoder_ids[i] != 0)
+		if (connector->encoder_ids[i] != 0 &&
+		    drm_lease_held(file_priv, connector->encoder_ids[i]))
 			encoders_count++;
 
 	if (out_resp->count_modes == 0) {
@@ -1118,7 +1119,7 @@ int drm_mode_getconnector(struct drm_device *dev, void *data,
 
 	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
 	encoder = drm_connector_get_encoder(connector);
-	if (encoder)
+	if (encoder && drm_lease_held(file_priv, encoder->base.id))
 		out_resp->encoder_id = encoder->base.id;
 	else
 		out_resp->encoder_id = 0;
@@ -1156,7 +1157,8 @@ int drm_mode_getconnector(struct drm_device *dev, void *data,
 		copied = 0;
 		encoder_ptr = (uint32_t __user *)(unsigned long)(out_resp->encoders_ptr);
 		for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
-			if (connector->encoder_ids[i] != 0) {
+			if (connector->encoder_ids[i] != 0 &&
+			    drm_lease_held(file_priv, connector->encoder_ids[i])) {
 				if (put_user(connector->encoder_ids[i],
 					     encoder_ptr + copied)) {
 					ret = -EFAULT;
diff --git a/drivers/gpu/drm/drm_encoder.c b/drivers/gpu/drm/drm_encoder.c
index dbaedd4e12e6..512d0b6cb7d2 100644
--- a/drivers/gpu/drm/drm_encoder.c
+++ b/drivers/gpu/drm/drm_encoder.c
@@ -211,7 +211,7 @@ int drm_mode_getencoder(struct drm_device *dev, void *data,
 
 	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
 	crtc = drm_encoder_get_crtc(encoder);
-	if (crtc)
+	if (crtc && drm_lease_held(file_priv, crtc->base.id))
 		enc_resp->crtc_id = crtc->base.id;
 	else
 		enc_resp->crtc_id = 0;
@@ -219,8 +219,10 @@ int drm_mode_getencoder(struct drm_device *dev, void *data,
 
 	enc_resp->encoder_type = encoder->encoder_type;
 	enc_resp->encoder_id = encoder->base.id;
-	enc_resp->possible_crtcs = encoder->possible_crtcs;
-	enc_resp->possible_clones = encoder->possible_clones;
+	enc_resp->possible_crtcs = drm_lease_filter_crtcs(file_priv,
+							  encoder->possible_crtcs);
+	enc_resp->possible_clones = drm_lease_filter_encoders(file_priv,
+							      encoder->possible_clones);
 
 	return 0;
 }
diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
index 2735a5847ffa..bb6b64e594b7 100644
--- a/drivers/gpu/drm/drm_mode_config.c
+++ b/drivers/gpu/drm/drm_mode_config.c
@@ -131,14 +131,20 @@ int drm_mode_getresources(struct drm_device *dev, void *data,
 	/* mode_config.mutex protects the connector list against e.g. DP MST
 	 * connector hot-adding. CRTC/Plane lists are invariant. */
 	mutex_lock(&dev->mode_config.mutex);
-	drm_for_each_crtc(crtc, dev)
-		crtc_count++;
+	drm_for_each_crtc(crtc, dev) {
+		if (drm_lease_held(file_priv, crtc->base.id))
+			crtc_count++;
+	}
 
-	drm_for_each_connector(connector, dev)
-		connector_count++;
+	drm_for_each_connector(connector, dev) {
+		if (drm_lease_held(file_priv, connector->base.id))
+			connector_count++;
+	}
 
-	drm_for_each_encoder(encoder, dev)
-		encoder_count++;
+	drm_for_each_encoder(encoder, dev) {
+		if (drm_lease_held(file_priv, encoder->base.id))
+			encoder_count++;
+	}
 
 	card_res->max_height = dev->mode_config.max_height;
 	card_res->min_height = dev->mode_config.min_height;
@@ -150,11 +156,13 @@ int drm_mode_getresources(struct drm_device *dev, void *data,
 		copied = 0;
 		crtc_id = (uint32_t __user *)(unsigned long)card_res->crtc_id_ptr;
 		drm_for_each_crtc(crtc, dev) {
-			if (put_user(crtc->base.id, crtc_id + copied)) {
-				ret = -EFAULT;
-				goto out;
+			if (drm_lease_held(file_priv, crtc->base.id)) {
+				if (put_user(crtc->base.id, crtc_id + copied)) {
+					ret = -EFAULT;
+					goto out;
+				}
+				copied++;
 			}
-			copied++;
 		}
 	}
 	card_res->count_crtcs = crtc_count;
@@ -164,12 +172,14 @@ int drm_mode_getresources(struct drm_device *dev, void *data,
 		copied = 0;
 		encoder_id = (uint32_t __user *)(unsigned long)card_res->encoder_id_ptr;
 		drm_for_each_encoder(encoder, dev) {
-			if (put_user(encoder->base.id, encoder_id +
-				     copied)) {
-				ret = -EFAULT;
-				goto out;
+			if (drm_lease_held(file_priv, encoder->base.id)) {
+				if (put_user(encoder->base.id, encoder_id +
+					     copied)) {
+					ret = -EFAULT;
+					goto out;
+				}
+				copied++;
 			}
-			copied++;
 		}
 	}
 	card_res->count_encoders = encoder_count;
@@ -179,12 +189,14 @@ int drm_mode_getresources(struct drm_device *dev, void *data,
 		copied = 0;
 		connector_id = (uint32_t __user *)(unsigned long)card_res->connector_id_ptr;
 		drm_for_each_connector(connector, dev) {
-			if (put_user(connector->base.id,
-				     connector_id + copied)) {
-				ret = -EFAULT;
-				goto out;
+			if (drm_lease_held(file_priv, connector->base.id)) {
+				if (put_user(connector->base.id,
+					     connector_id + copied)) {
+					ret = -EFAULT;
+					goto out;
+				}
+				copied++;
 			}
-			copied++;
 		}
 	}
 	card_res->count_connectors = connector_count;
diff --git a/drivers/gpu/drm/drm_mode_object.c b/drivers/gpu/drm/drm_mode_object.c
index daddc7640139..9763787492cc 100644
--- a/drivers/gpu/drm/drm_mode_object.c
+++ b/drivers/gpu/drm/drm_mode_object.c
@@ -107,6 +107,25 @@ void drm_mode_object_unregister(struct drm_device *dev,
 	mutex_unlock(&dev->mode_config.idr_mutex);
 }
 
+/**
+ * drm_lease_required - check types which must be leased to be used
+ * @type: type of object
+ *
+ * Returns whether the provided type of drm_mode_object must
+ * be owned or leased to be used by a process.
+ */
+static bool drm_lease_required(uint32_t type)
+{
+	switch(type) {
+	case DRM_MODE_OBJECT_CRTC:
+	case DRM_MODE_OBJECT_CONNECTOR:
+	case DRM_MODE_OBJECT_ENCODER:
+		return true;
+	default:
+		return false;
+	}
+}
+
 struct drm_mode_object *__drm_mode_object_find(struct drm_device *dev,
 					       struct drm_file *file_priv,
 					       uint32_t id, uint32_t type)
@@ -120,6 +139,9 @@ struct drm_mode_object *__drm_mode_object_find(struct drm_device *dev,
 	if (obj && obj->id != id)
 		obj = NULL;
 
+	if (obj && drm_lease_required(obj->type) && !_drm_lease_held(file_priv, obj->id))
+		obj = NULL;
+
 	if (obj && obj->free_cb) {
 		if (!kref_get_unless_zero(&obj->refcount))
 			obj = NULL;
diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c
index 819f74616f34..c9c687cdc747 100644
--- a/drivers/gpu/drm/drm_plane.c
+++ b/drivers/gpu/drm/drm_plane.c
@@ -392,7 +392,7 @@ int drm_mode_getplane(struct drm_device *dev, void *data,
 		return -ENOENT;
 
 	drm_modeset_lock(&plane->mutex, NULL);
-	if (plane->crtc)
+	if (plane->crtc && drm_lease_held(file_priv, plane->crtc->base.id))
 		plane_resp->crtc_id = plane->crtc->base.id;
 	else
 		plane_resp->crtc_id = 0;
@@ -404,7 +404,9 @@ int drm_mode_getplane(struct drm_device *dev, void *data,
 	drm_modeset_unlock(&plane->mutex);
 
 	plane_resp->plane_id = plane->base.id;
-	plane_resp->possible_crtcs = plane->possible_crtcs;
+	plane_resp->possible_crtcs = drm_lease_filter_crtcs(file_priv,
+							    plane->possible_crtcs);
+
 	plane_resp->gamma_size = 0;
 
 	/*
-- 
2.11.0
