Merge tag 'v3.12'

Linux 3.12

Conflicts:
	fs/exec.c

1 files changed, 43 insertions, 26 deletions

diff --git a/ipc/msg.c b/ipc/msg.c
index 9f29d9e89bac..558aa91186b6 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -70,8 +70,6 @@ struct msg_sender {
 
 #define msg_ids(ns)     ((ns)->ids[IPC_MSG_IDS])
 
-#define msg_unlock(msq)         ipc_unlock(&(msq)->q_perm)
-
 static void freeque(struct ipc_namespace *, struct kern_ipc_perm *);
 static int newque(struct ipc_namespace *, struct ipc_params *);
 #ifdef CONFIG_PROC_FS
@@ -167,12 +165,21 @@ 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
  * @params: ptr to the structure that contains the key and msgflg
  *
- * Called with msg_ids.rw_mutex held (writer)
+ * Called with msg_ids.rwsem held (writer)
  */
 static int newque(struct ipc_namespace *ns, struct ipc_params *params)
 {
@@ -191,15 +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;
         }
 
@@ -259,8 +265,8 @@ static void expunge_all(struct msg_queue *msq, int res)
  * removes the message queue from message queue ID IDR, and cleans up all the
  * messages associated with this queue.
  *
- * msg_ids.rw_mutex (writer) and the spinlock for this message queue are held
- * before freeque() is called. msg_ids.rw_mutex remains locked on exit.
+ * msg_ids.rwsem (writer) and the spinlock for this message queue are held
+ * before freeque() is called. msg_ids.rwsem remains locked on exit.
  */
 static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
 {
@@ -270,19 +276,19 @@ static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
         expunge_all(msq, -EIDRM);
         ss_wakeup(&msq->q_senders, 1);
         msg_rmid(ns, msq);
-        msg_unlock(msq);
+        ipc_unlock_object(&msq->q_perm);
+        rcu_read_unlock();
 
         list_for_each_entry_safe(msg, t, &msq->q_messages, m_list) {
                 atomic_dec(&ns->msg_hdrs);
                 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);
 }
 
 /*
- * Called with msg_ids.rw_mutex and ipcp locked.
+ * Called with msg_ids.rwsem and ipcp locked.
  */
 static inline int msg_security(struct kern_ipc_perm *ipcp, int msgflg)
 {
@@ -386,9 +392,9 @@ copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version)
 }
 
 /*
- * This function handles some msgctl commands which require the rw_mutex
+ * This function handles some msgctl commands which require the rwsem
  * to be held in write mode.
- * NOTE: no locks must be held, the rw_mutex is taken inside this function.
+ * NOTE: no locks must be held, the rwsem is taken inside this function.
  */
 static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
                        struct msqid_ds __user *buf, int version)
@@ -403,7 +409,7 @@ static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
                         return -EFAULT;
         }
 
-        down_write(&msg_ids(ns).rw_mutex);
+        down_write(&msg_ids(ns).rwsem);
         rcu_read_lock();
 
         ipcp = ipcctl_pre_down_nolock(ns, &msg_ids(ns), msqid, cmd,
@@ -459,7 +465,7 @@ out_unlock0:
 out_unlock1:
         rcu_read_unlock();
 out_up:
-        up_write(&msg_ids(ns).rw_mutex);
+        up_write(&msg_ids(ns).rwsem);
         return err;
 }
 
@@ -494,7 +500,7 @@ static int msgctl_nolock(struct ipc_namespace *ns, int msqid,
                 msginfo.msgmnb = ns->msg_ctlmnb;
                 msginfo.msgssz = MSGSSZ;
                 msginfo.msgseg = MSGSEG;
-                down_read(&msg_ids(ns).rw_mutex);
+                down_read(&msg_ids(ns).rwsem);
                 if (cmd == MSG_INFO) {
                         msginfo.msgpool = msg_ids(ns).in_use;
                         msginfo.msgmap = atomic_read(&ns->msg_hdrs);
@@ -505,7 +511,7 @@ static int msgctl_nolock(struct ipc_namespace *ns, int msqid,
                         msginfo.msgtql = MSGTQL;
                 }
                 max_id = ipc_get_maxid(&msg_ids(ns));
-                up_read(&msg_ids(ns).rw_mutex);
+                up_read(&msg_ids(ns).rwsem);
                 if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))
                         return -EFAULT;
                 return (max_id < 0) ? 0 : max_id;
@@ -680,16 +686,24 @@ long do_msgsnd(int msqid, long mtype, void __user *mtext,
                 goto out_unlock1;
         }
 
+        ipc_lock_object(&msq->q_perm);
+
         for (;;) {
                 struct msg_sender s;
 
                 err = -EACCES;
                 if (ipcperms(ns, &msq->q_perm, S_IWUGO))
-                        goto out_unlock1;
+                        goto out_unlock0;
+
+                /* raced with RMID? */
+                if (msq->q_perm.deleted) {
+                        err = -EIDRM;
+                        goto out_unlock0;
+                }
 
                 err = security_msg_queue_msgsnd(msq, msg, msgflg);
                 if (err)
-                        goto out_unlock1;
+                        goto out_unlock0;
 
                 if (msgsz + msq->q_cbytes <= msq->q_qbytes &&
                                 1 + msq->q_qnum <= msq->q_qbytes) {
@@ -699,10 +713,9 @@ long do_msgsnd(int msqid, long mtype, void __user *mtext,
                 /* queue full, wait: */
                 if (msgflg & IPC_NOWAIT) {
                         err = -EAGAIN;
-                        goto out_unlock1;
+                        goto out_unlock0;
                 }
 
-                ipc_lock_object(&msq->q_perm);
                 ss_add(msq, &s);
 
                 if (!ipc_rcu_getref(msq)) {
@@ -717,7 +730,7 @@ 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;
@@ -730,10 +743,7 @@ long do_msgsnd(int msqid, long mtype, void __user *mtext,
                         goto out_unlock0;
                 }
 
-                ipc_unlock_object(&msq->q_perm);
         }
-
-        ipc_lock_object(&msq->q_perm);
         msq->q_lspid = task_tgid_vnr(current);
         msq->q_stime = get_seconds();
 
@@ -897,6 +907,13 @@ long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgfl
                         goto out_unlock1;
 
                 ipc_lock_object(&msq->q_perm);
+
+                /* raced with RMID? */
+                if (msq->q_perm.deleted) {
+                        msg = ERR_PTR(-EIDRM);
+                        goto out_unlock0;
+                }
+
                 msg = find_msg(msq, &msgtyp, mode);
                 if (!IS_ERR(msg)) {
                         /*