diff options
Diffstat (limited to 'ipc/msg.c')
| -rw-r--r-- | ipc/msg.c | 24 |
1 files changed, 17 insertions, 7 deletions
diff --git a/ipc/msg.c b/ipc/msg.c index 7a3d6aab369d..f62fa5eed847 100644 --- a/ipc/msg.c +++ b/ipc/msg.c @@ -407,31 +407,38 @@ static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd, return -EFAULT; } + down_write(&msg_ids(ns).rw_mutex); + rcu_read_lock(); + ipcp = ipcctl_pre_down(ns, &msg_ids(ns), msqid, cmd, &msqid64.msg_perm, msqid64.msg_qbytes); - if (IS_ERR(ipcp)) - return PTR_ERR(ipcp); + if (IS_ERR(ipcp)) { + err = PTR_ERR(ipcp); + /* the ipc lock is not held upon failure */ + goto out_unlock1; + } msq = container_of(ipcp, struct msg_queue, q_perm); err = security_msg_queue_msgctl(msq, cmd); if (err) - goto out_unlock; + goto out_unlock0; switch (cmd) { case IPC_RMID: + /* freeque unlocks the ipc object and rcu */ freeque(ns, ipcp); goto out_up; case IPC_SET: if (msqid64.msg_qbytes > ns->msg_ctlmnb && !capable(CAP_SYS_RESOURCE)) { err = -EPERM; - goto out_unlock; + goto out_unlock0; } err = ipc_update_perm(&msqid64.msg_perm, ipcp); if (err) - goto out_unlock; + goto out_unlock0; msq->q_qbytes = msqid64.msg_qbytes; @@ -448,8 +455,11 @@ static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd, default: err = -EINVAL; } -out_unlock: - msg_unlock(msq); + +out_unlock0: + ipc_unlock_object(&msq->q_perm); +out_unlock1: + rcu_read_unlock(); out_up: up_write(&msg_ids(ns).rw_mutex); return err; |