audit: Use rcu for task lookup protection

[cascardo/linux.git] / kernel / audit.c

diff --git a/kernel/audit.c b/kernel/audit.c
index 57f4038..77770a0 100644 (file)
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -873,17 +873,16 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
        case AUDIT_TTY_GET: {
                struct audit_tty_status s;
                struct task_struct *tsk;
+               unsigned long flags;
 
-               read_lock(&tasklist_lock);
+               rcu_read_lock();
                tsk = find_task_by_vpid(pid);
-               if (!tsk)
-                       err = -ESRCH;
-               else {
-                       spin_lock_irq(&tsk->sighand->siglock);
+               if (tsk && lock_task_sighand(tsk, &flags)) {
                        s.enabled = tsk->signal->audit_tty != 0;
-                       spin_unlock_irq(&tsk->sighand->siglock);
-               }
-               read_unlock(&tasklist_lock);
+                       unlock_task_sighand(tsk, &flags);
+               } else
+                       err = -ESRCH;
+               rcu_read_unlock();
 
                if (!err)
                        audit_send_reply(NETLINK_CB(skb).pid, seq,
@@ -893,22 +892,21 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
        case AUDIT_TTY_SET: {
                struct audit_tty_status *s;
                struct task_struct *tsk;
+               unsigned long flags;
 
                if (nlh->nlmsg_len < sizeof(struct audit_tty_status))
                        return -EINVAL;
                s = data;
                if (s->enabled != 0 && s->enabled != 1)
                        return -EINVAL;
-               read_lock(&tasklist_lock);
+               rcu_read_lock();
                tsk = find_task_by_vpid(pid);
-               if (!tsk)
-                       err = -ESRCH;
-               else {
-                       spin_lock_irq(&tsk->sighand->siglock);
+               if (tsk && lock_task_sighand(tsk, &flags)) {
                        tsk->signal->audit_tty = s->enabled != 0;
-                       spin_unlock_irq(&tsk->sighand->siglock);
-               }
-               read_unlock(&tasklist_lock);
+                       unlock_task_sighand(tsk, &flags);
+               } else
+                       err = -ESRCH;
+               rcu_read_unlock();
                break;
        }
        default: