SELinux: Improve read/write performance
It reduces the selinux overhead on read/write by only revalidating
permissions in selinux_file_permission if the task or inode labels have
changed or the policy has changed since the open-time check. A new LSM
hook, security_dentry_open, is added to capture the necessary state at open
time to allow this optimization.
(see http://marc.info/?l=selinux&m=118972995207740&w=2)
Signed-off-by: Yuichi Nakamura<ynakam@hitachisoft.jp>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/include/linux/security.h b/include/linux/security.h
index 1a15526..928d479 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -504,6 +504,13 @@
* @file contains the file structure being received.
* Return 0 if permission is granted.
*
+ * Security hook for dentry
+ *
+ * @dentry_open
+ * Save open-time permission checking state for later use upon
+ * file_permission, and recheck access if anything has changed
+ * since inode_permission.
+ *
* Security hooks for task operations.
*
* @task_create:
@@ -1256,6 +1263,7 @@
int (*file_send_sigiotask) (struct task_struct * tsk,
struct fown_struct * fown, int sig);
int (*file_receive) (struct file * file);
+ int (*dentry_open) (struct file *file);
int (*task_create) (unsigned long clone_flags);
int (*task_alloc_security) (struct task_struct * p);
@@ -1864,6 +1872,11 @@
return security_ops->file_receive (file);
}
+static inline int security_dentry_open (struct file *file)
+{
+ return security_ops->dentry_open (file);
+}
+
static inline int security_task_create (unsigned long clone_flags)
{
return security_ops->task_create (clone_flags);
@@ -2546,6 +2559,11 @@
return 0;
}
+static inline int security_dentry_open (struct file *file)
+{
+ return 0;
+}
+
static inline int security_task_create (unsigned long clone_flags)
{
return 0;