ipc,msg: make msgctl_nolock lockless
commit ac0ba20ea6f2201a1589d6dc26ad1a4f0f967bb8 upstream. While the INFO cmd doesn't take the ipc lock, the STAT commands do acquire it unnecessarily. We can do the permissions and security checks only holding the rcu lock. This function now mimics semctl_nolock(). Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
15d49ab481
commit
107b413cd3
27
ipc/msg.c
27
ipc/msg.c
|
@ -545,17 +545,25 @@ static int msgctl_nolock(struct ipc_namespace *ns, int msqid,
|
|||
if (!buf)
|
||||
return -EFAULT;
|
||||
|
||||
memset(&tbuf, 0, sizeof(tbuf));
|
||||
|
||||
rcu_read_lock();
|
||||
if (cmd == MSG_STAT) {
|
||||
msq = msg_lock(ns, msqid);
|
||||
if (IS_ERR(msq))
|
||||
return PTR_ERR(msq);
|
||||
msq = msq_obtain_object(ns, msqid);
|
||||
if (IS_ERR(msq)) {
|
||||
err = PTR_ERR(msq);
|
||||
goto out_unlock;
|
||||
}
|
||||
success_return = msq->q_perm.id;
|
||||
} else {
|
||||
msq = msg_lock_check(ns, msqid);
|
||||
if (IS_ERR(msq))
|
||||
return PTR_ERR(msq);
|
||||
msq = msq_obtain_object_check(ns, msqid);
|
||||
if (IS_ERR(msq)) {
|
||||
err = PTR_ERR(msq);
|
||||
goto out_unlock;
|
||||
}
|
||||
success_return = 0;
|
||||
}
|
||||
|
||||
err = -EACCES;
|
||||
if (ipcperms(ns, &msq->q_perm, S_IRUGO))
|
||||
goto out_unlock;
|
||||
|
@ -564,8 +572,6 @@ static int msgctl_nolock(struct ipc_namespace *ns, int msqid,
|
|||
if (err)
|
||||
goto out_unlock;
|
||||
|
||||
memset(&tbuf, 0, sizeof(tbuf));
|
||||
|
||||
kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm);
|
||||
tbuf.msg_stime = msq->q_stime;
|
||||
tbuf.msg_rtime = msq->q_rtime;
|
||||
|
@ -575,7 +581,8 @@ static int msgctl_nolock(struct ipc_namespace *ns, int msqid,
|
|||
tbuf.msg_qbytes = msq->q_qbytes;
|
||||
tbuf.msg_lspid = msq->q_lspid;
|
||||
tbuf.msg_lrpid = msq->q_lrpid;
|
||||
msg_unlock(msq);
|
||||
rcu_read_unlock();
|
||||
|
||||
if (copy_msqid_to_user(buf, &tbuf, version))
|
||||
return -EFAULT;
|
||||
return success_return;
|
||||
|
@ -587,7 +594,7 @@ static int msgctl_nolock(struct ipc_namespace *ns, int msqid,
|
|||
|
||||
return err;
|
||||
out_unlock:
|
||||
msg_unlock(msq);
|
||||
rcu_read_unlock();
|
||||
return err;
|
||||
}
|
||||
|
||||
|
|
Loading…
Reference in New Issue