diff options
| -rw-r--r-- | security/selinux/hooks.c | 20 | ||||
| -rw-r--r-- | security/selinux/include/objsec.h | 5 |
2 files changed, 22 insertions, 3 deletions
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 49ddc59..a4ecefc 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -215,6 +215,14 @@ 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; @@ -225,8 +233,16 @@ 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 26c7eee..7b1830b 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 */ |