2 files changed, 22 insertions, 3 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 6625699f497c..57b0b49f4e6e 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -234,6 +234,14 @@ static int inode_alloc_security(struct inode *inode)
         return 0;
 }
 
+static void inode_free_rcu(struct rcu_head *head)
+{
+        struct inode_security_struct *isec;
+
+        isec = container_of(head, struct inode_security_struct, rcu);
+        kmem_cache_free(sel_inode_cache, isec);
+}
+
 static void inode_free_security(struct inode *inode)
 {
         struct inode_security_struct *isec = inode->i_security;
@@ -244,8 +252,16 @@ static void inode_free_security(struct inode *inode)
                 list_del_init(&isec->list);
         spin_unlock(&sbsec->isec_lock);
 
-        inode->i_security = NULL;
-        kmem_cache_free(sel_inode_cache, isec);
+        /*
+         * The inode may still be referenced in a path walk and
+         * a call to selinux_inode_permission() can be made
+         * after inode_free_security() is called. Ideally, the VFS
+         * wouldn't do this, but fixing that is a much harder
+         * job. For now, simply free the i_security via RCU, and
+         * leave the current inode->i_security pointer intact.
+         * The inode will be freed after the RCU grace period too.
+         */
+        call_rcu(&isec->rcu, inode_free_rcu);
 }
 
 static int file_alloc_security(struct file *file)
diff --git a/security/selinux/include/objsec.h b/security/selinux/include/objsec.h
index b1dfe1049450..078e553f52f2 100644
--- a/security/selinux/include/objsec.h
+++ b/security/selinux/include/objsec.h
@@ -38,7 +38,10 @@ struct task_security_struct {
 
 struct inode_security_struct {
         struct inode *inode;    /* back pointer to inode object */
-        struct list_head list;  /* list of inode_security_struct */
+        union {
+                struct list_head list;  /* list of inode_security_struct */
+                struct rcu_head rcu;    /* for freeing the inode_security_struct */
+        };
         u32 task_sid;           /* SID of creating task */
         u32 sid;                /* SID of this object */
         u16 sclass;             /* security class of this object */