[PATCH] drm/ttm: ttm object security fixes for render nodes
Thomas Hellstrom
thellstrom at vmware.com
Wed Jan 8 01:13:22 PST 2014
When a client looks up a ttm object, don't look it up through the device hash
table, but rather from the file hash table. That makes sure that the client
has indeed put a reference on the object, or in gem terms, has opened
the object; either using prime or using the global "name".
To avoid a performance loss, make sure the file hash table entries can be
looked up from under an RCU lock, and as a consequence, replace the rwlock
with a spinlock, since we never need to take it in read mode only anymore.
Finally add a ttm object lookup function for the device hash table, that is
intended to be used when we put a ref object on a base object or, in gem terms,
when we open the object.
Signed-off-by: Thomas Hellstrom <thellstrom at vmware.com>
Reviewed-by: Brian Paul <brianp at vmware.com>
---
drivers/gpu/drm/ttm/ttm_object.c | 90 ++++++++++++++++++-------------
drivers/gpu/drm/vmwgfx/vmwgfx_fence.c | 3 +-
drivers/gpu/drm/vmwgfx/vmwgfx_surface.c | 3 +-
include/drm/ttm/ttm_object.h | 18 ++++++-
4 files changed, 74 insertions(+), 40 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_object.c b/drivers/gpu/drm/ttm/ttm_object.c
index 6fe7b92..3707985 100644
--- a/drivers/gpu/drm/ttm/ttm_object.c
+++ b/drivers/gpu/drm/ttm/ttm_object.c
@@ -68,7 +68,7 @@
struct ttm_object_file {
struct ttm_object_device *tdev;
- rwlock_t lock;
+ spinlock_t lock;
struct list_head ref_list;
struct drm_open_hash ref_hash[TTM_REF_NUM];
struct kref refcount;
@@ -118,6 +118,7 @@ struct ttm_object_device {
*/
struct ttm_ref_object {
+ struct rcu_head rcu_head;
struct drm_hash_item hash;
struct list_head head;
struct kref kref;
@@ -210,10 +211,9 @@ static void ttm_release_base(struct kref *kref)
* call_rcu() or ttm_base_object_kfree().
*/
- if (base->refcount_release) {
- ttm_object_file_unref(&base->tfile);
+ ttm_object_file_unref(&base->tfile);
+ if (base->refcount_release)
base->refcount_release(&base);
- }
}
void ttm_base_object_unref(struct ttm_base_object **p_base)
@@ -229,32 +229,46 @@ EXPORT_SYMBOL(ttm_base_object_unref);
struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file *tfile,
uint32_t key)
{
- struct ttm_object_device *tdev = tfile->tdev;
- struct ttm_base_object *uninitialized_var(base);
+ struct ttm_base_object *base = NULL;
struct drm_hash_item *hash;
+ struct drm_open_hash *ht = &tfile->ref_hash[TTM_REF_USAGE];
int ret;
rcu_read_lock();
- ret = drm_ht_find_item_rcu(&tdev->object_hash, key, &hash);
+ ret = drm_ht_find_item_rcu(ht, key, &hash);
if (likely(ret == 0)) {
- base = drm_hash_entry(hash, struct ttm_base_object, hash);
- ret = kref_get_unless_zero(&base->refcount) ? 0 : -EINVAL;
+ base = drm_hash_entry(hash, struct ttm_ref_object, hash)->obj;
+ if (!kref_get_unless_zero(&base->refcount))
+ base = NULL;
}
rcu_read_unlock();
- if (unlikely(ret != 0))
- return NULL;
+ return base;
+}
+EXPORT_SYMBOL(ttm_base_object_lookup);
- if (tfile != base->tfile && !base->shareable) {
- pr_err("Attempted access of non-shareable object\n");
- ttm_base_object_unref(&base);
- return NULL;
+struct ttm_base_object *
+ttm_base_object_lookup_for_ref(struct ttm_object_device *tdev, uint32_t key)
+{
+ struct ttm_base_object *base = NULL;
+ struct drm_hash_item *hash;
+ struct drm_open_hash *ht = &tdev->object_hash;
+ int ret;
+
+ rcu_read_lock();
+ ret = drm_ht_find_item_rcu(ht, key, &hash);
+
+ if (likely(ret == 0)) {
+ base = drm_hash_entry(hash, struct ttm_base_object, hash);
+ if (!kref_get_unless_zero(&base->refcount))
+ base = NULL;
}
+ rcu_read_unlock();
return base;
}
-EXPORT_SYMBOL(ttm_base_object_lookup);
+EXPORT_SYMBOL(ttm_base_object_lookup_for_ref);
int ttm_ref_object_add(struct ttm_object_file *tfile,
struct ttm_base_object *base,
@@ -266,21 +280,25 @@ int ttm_ref_object_add(struct ttm_object_file *tfile,
struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob;
int ret = -EINVAL;
+ if (base->tfile != tfile && !base->shareable)
+ return -EPERM;
+
if (existed != NULL)
*existed = true;
while (ret == -EINVAL) {
- read_lock(&tfile->lock);
- ret = drm_ht_find_item(ht, base->hash.key, &hash);
+ rcu_read_lock();
+ ret = drm_ht_find_item_rcu(ht, base->hash.key, &hash);
if (ret == 0) {
ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
- kref_get(&ref->kref);
- read_unlock(&tfile->lock);
- break;
+ if (!kref_get_unless_zero(&ref->kref)) {
+ rcu_read_unlock();
+ break;
+ }
}
- read_unlock(&tfile->lock);
+ rcu_read_unlock();
ret = ttm_mem_global_alloc(mem_glob, sizeof(*ref),
false, false);
if (unlikely(ret != 0))
@@ -297,19 +315,19 @@ int ttm_ref_object_add(struct ttm_object_file *tfile,
ref->ref_type = ref_type;
kref_init(&ref->kref);
- write_lock(&tfile->lock);
- ret = drm_ht_insert_item(ht, &ref->hash);
+ spin_lock(&tfile->lock);
+ ret = drm_ht_insert_item_rcu(ht, &ref->hash);
if (likely(ret == 0)) {
list_add_tail(&ref->head, &tfile->ref_list);
kref_get(&base->refcount);
- write_unlock(&tfile->lock);
+ spin_unlock(&tfile->lock);
if (existed != NULL)
*existed = false;
break;
}
- write_unlock(&tfile->lock);
+ spin_unlock(&tfile->lock);
BUG_ON(ret != -EINVAL);
ttm_mem_global_free(mem_glob, sizeof(*ref));
@@ -330,17 +348,17 @@ static void ttm_ref_object_release(struct kref *kref)
struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob;
ht = &tfile->ref_hash[ref->ref_type];
- (void)drm_ht_remove_item(ht, &ref->hash);
+ (void)drm_ht_remove_item_rcu(ht, &ref->hash);
list_del(&ref->head);
- write_unlock(&tfile->lock);
+ spin_unlock(&tfile->lock);
if (ref->ref_type != TTM_REF_USAGE && base->ref_obj_release)
base->ref_obj_release(base, ref->ref_type);
ttm_base_object_unref(&ref->obj);
ttm_mem_global_free(mem_glob, sizeof(*ref));
- kfree(ref);
- write_lock(&tfile->lock);
+ kfree_rcu(ref, rcu_head);
+ spin_lock(&tfile->lock);
}
int ttm_ref_object_base_unref(struct ttm_object_file *tfile,
@@ -351,15 +369,15 @@ int ttm_ref_object_base_unref(struct ttm_object_file *tfile,
struct drm_hash_item *hash;
int ret;
- write_lock(&tfile->lock);
+ spin_lock(&tfile->lock);
ret = drm_ht_find_item(ht, key, &hash);
if (unlikely(ret != 0)) {
- write_unlock(&tfile->lock);
+ spin_unlock(&tfile->lock);
return -EINVAL;
}
ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
kref_put(&ref->kref, ttm_ref_object_release);
- write_unlock(&tfile->lock);
+ spin_unlock(&tfile->lock);
return 0;
}
EXPORT_SYMBOL(ttm_ref_object_base_unref);
@@ -372,7 +390,7 @@ void ttm_object_file_release(struct ttm_object_file **p_tfile)
struct ttm_object_file *tfile = *p_tfile;
*p_tfile = NULL;
- write_lock(&tfile->lock);
+ spin_lock(&tfile->lock);
/*
* Since we release the lock within the loop, we have to
@@ -388,7 +406,7 @@ void ttm_object_file_release(struct ttm_object_file **p_tfile)
for (i = 0; i < TTM_REF_NUM; ++i)
drm_ht_remove(&tfile->ref_hash[i]);
- write_unlock(&tfile->lock);
+ spin_unlock(&tfile->lock);
ttm_object_file_unref(&tfile);
}
EXPORT_SYMBOL(ttm_object_file_release);
@@ -404,7 +422,7 @@ struct ttm_object_file *ttm_object_file_init(struct ttm_object_device *tdev,
if (unlikely(tfile == NULL))
return NULL;
- rwlock_init(&tfile->lock);
+ spin_lock_init(&tfile->lock);
tfile->tdev = tdev;
kref_init(&tfile->refcount);
INIT_LIST_HEAD(&tfile->ref_list);
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
index c62d20e..5d3f677 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
@@ -1080,7 +1080,8 @@ int vmw_fence_event_ioctl(struct drm_device *dev, void *data,
*/
if (arg->handle) {
struct ttm_base_object *base =
- ttm_base_object_lookup(vmw_fp->tfile, arg->handle);
+ ttm_base_object_lookup_for_ref(dev_priv->tdev,
+ arg->handle);
if (unlikely(base == NULL)) {
DRM_ERROR("Fence event invalid fence object handle "
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
index 7de2ea8..0fc9339 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
@@ -843,6 +843,7 @@ out_unlock:
int vmw_surface_reference_ioctl(struct drm_device *dev, void *data,
struct drm_file *file_priv)
{
+ struct vmw_private *dev_priv = vmw_priv(dev);
union drm_vmw_surface_reference_arg *arg =
(union drm_vmw_surface_reference_arg *)data;
struct drm_vmw_surface_arg *req = &arg->req;
@@ -854,7 +855,7 @@ int vmw_surface_reference_ioctl(struct drm_device *dev, void *data,
struct ttm_base_object *base;
int ret = -EINVAL;
- base = ttm_base_object_lookup(tfile, req->sid);
+ base = ttm_base_object_lookup_for_ref(dev_priv->tdev, req->sid);
if (unlikely(base == NULL)) {
DRM_ERROR("Could not find surface to reference.\n");
return -EINVAL;
diff --git a/include/drm/ttm/ttm_object.h b/include/drm/ttm/ttm_object.h
index 58b0298..0097cc0 100644
--- a/include/drm/ttm/ttm_object.h
+++ b/include/drm/ttm/ttm_object.h
@@ -190,14 +190,26 @@ extern int ttm_base_object_init(struct ttm_object_file *tfile,
* @key: Hash key
*
* Looks up a struct ttm_base_object with the key @key.
- * Also verifies that the object is visible to the application, by
- * comparing the @tfile argument and checking the object shareable flag.
*/
extern struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file
*tfile, uint32_t key);
/**
+ * ttm_base_object_lookup_for_ref
+ *
+ * @tdev: Pointer to a struct ttm_object_device.
+ * @key: Hash key
+ *
+ * Looks up a struct ttm_base_object with the key @key.
+ * This function should only be used when the struct tfile associated with the
+ * caller doesn't yet have a reference to the base object.
+ */
+
+extern struct ttm_base_object *
+ttm_base_object_lookup_for_ref(struct ttm_object_device *tdev, uint32_t key);
+
+/**
* ttm_base_object_unref
*
* @p_base: Pointer to a pointer referencing a struct ttm_base_object.
@@ -218,6 +230,8 @@ extern void ttm_base_object_unref(struct ttm_base_object **p_base);
* @existed: Upon completion, indicates that an identical reference object
* already existed, and the refcount was upped on that object instead.
*
+ * Checks that the base object is shareable and adds a ref object to it.
+ *
* Adding a ref object to a base object is basically like referencing the
* base object, but a user-space application holds the reference. When the
* file corresponding to @tfile is closed, all its reference objects are
--
1.7.10.4
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