ipc: fix race with LSMs

[karo-tx-linux.git] / ipc / msg.c

diff --git a/ipc/msg.c b/ipc/msg.c
index b0d541d426771caec217961b031e3de191135ced..9e4310c546ae93fa85f3932675bcd53ae33ece7a 100644 (file)
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -165,6 +165,15 @@ static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
        ipc_rmid(&msg_ids(ns), &s->q_perm);
 }
 
+static void msg_rcu_free(struct rcu_head *head)
+{
+       struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu);
+       struct msg_queue *msq = ipc_rcu_to_struct(p);
+
+       security_msg_queue_free(msq);
+       ipc_rcu_free(head);
+}
+
 /**
  * newque - Create a new msg queue
  * @ns: namespace
@@ -189,15 +198,14 @@ static int newque(struct ipc_namespace *ns, struct ipc_params *params)
        msq->q_perm.security = NULL;
        retval = security_msg_queue_alloc(msq);
        if (retval) {
-               ipc_rcu_putref(msq);
+               ipc_rcu_putref(msq, ipc_rcu_free);
                return retval;
        }
 
        /* ipc_addid() locks msq upon success. */
        id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni);
        if (id < 0) {
-               security_msg_queue_free(msq);
-               ipc_rcu_putref(msq);
+               ipc_rcu_putref(msq, msg_rcu_free);
                return id;
        }
 
@@ -276,8 +284,7 @@ static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
                free_msg(msg);
        }
        atomic_sub(msq->q_cbytes, &ns->msg_bytes);
-       security_msg_queue_free(msq);
-       ipc_rcu_putref(msq);
+       ipc_rcu_putref(msq, msg_rcu_free);
 }
 
 /*
@@ -717,7 +724,7 @@ long do_msgsnd(int msqid, long mtype, void __user *mtext,
                rcu_read_lock();
                ipc_lock_object(&msq->q_perm);
 
-               ipc_rcu_putref(msq);
+               ipc_rcu_putref(msq, ipc_rcu_free);
                if (msq->q_perm.deleted) {
                        err = -EIDRM;
                        goto out_unlock0;