audit: use spin_lock_irqsave/restore in audit tty code

Some of the callers of the audit tty function use spin_lock_irqsave/restore.
We were using the forced always enable version, which seems really bad.
Since I don't know every one of these code paths well enough, it makes
sense to just switch everything to the safe version.  Maybe it's a
little overzealous, but it's a lot better than an unlucky deadlock when
we return to a caller with irq enabled and they expect it to be
disabled.
Signed-off-by: NEric Paris <eparis@redhat.com>

drivers/tty/tty_audit.c

@@ -111,11 +111,12 @@ static void tty_audit_buf_push(struct tty_audit_buf *buf)
 void tty_audit_exit(void)
 {
 	struct tty_audit_buf *buf;
+	unsigned long flags;
 
-	spin_lock_irq(&current->sighand->siglock);
+	spin_lock_irqsave(&current->sighand->siglock, flags);
 	buf = current->signal->tty_audit_buf;
 	current->signal->tty_audit_buf = NULL;
-	spin_unlock_irq(&current->sighand->siglock);
+	spin_unlock_irqrestore(&current->sighand->siglock, flags);
 	if (!buf)
 		return;
 
@@ -133,9 +134,11 @@ void tty_audit_exit(void)
  */
 void tty_audit_fork(struct signal_struct *sig)
 {
-	spin_lock_irq(&current->sighand->siglock);
+	unsigned long flags;
+
+	spin_lock_irqsave(&current->sighand->siglock, flags);
 	sig->audit_tty = current->signal->audit_tty;
-	spin_unlock_irq(&current->sighand->siglock);
+	spin_unlock_irqrestore(&current->sighand->siglock, flags);
 }
 
 /**
@@ -145,13 +148,14 @@ void tty_audit_tiocsti(struct tty_struct *tty, char ch)
 {
 	struct tty_audit_buf *buf;
 	int major, minor, should_audit;
+	unsigned long flags;
 
-	spin_lock_irq(&current->sighand->siglock);
+	spin_lock_irqsave(&current->sighand->siglock, flags);
 	should_audit = current->signal->audit_tty;
 	buf = current->signal->tty_audit_buf;
 	if (buf)
 		atomic_inc(&buf->count);
-	spin_unlock_irq(&current->sighand->siglock);
+	spin_unlock_irqrestore(&current->sighand->siglock, flags);
 
 	major = tty->driver->major;
 	minor = tty->driver->minor_start + tty->index;
@@ -221,10 +225,11 @@ static struct tty_audit_buf *tty_audit_buf_get(struct tty_struct *tty,
 		unsigned icanon)
 {
 	struct tty_audit_buf *buf, *buf2;
+	unsigned long flags;
 
 	buf = NULL;
 	buf2 = NULL;
-	spin_lock_irq(&current->sighand->siglock);
+	spin_lock_irqsave(&current->sighand->siglock, flags);
 	if (likely(!current->signal->audit_tty))
 		goto out;
 	buf = current->signal->tty_audit_buf;
@@ -232,7 +237,7 @@ static struct tty_audit_buf *tty_audit_buf_get(struct tty_struct *tty,
 		atomic_inc(&buf->count);
 		goto out;
 	}
-	spin_unlock_irq(&current->sighand->siglock);
+	spin_unlock_irqrestore(&current->sighand->siglock, flags);
 
 	buf2 = tty_audit_buf_alloc(tty->driver->major,
 				   tty->driver->minor_start + tty->index,
@@ -242,7 +247,7 @@ static struct tty_audit_buf *tty_audit_buf_get(struct tty_struct *tty,
 		return NULL;
 	}
 
-	spin_lock_irq(&current->sighand->siglock);
+	spin_lock_irqsave(&current->sighand->siglock, flags);
 	if (!current->signal->audit_tty)
 		goto out;
 	buf = current->signal->tty_audit_buf;
@@ -254,7 +259,7 @@ static struct tty_audit_buf *tty_audit_buf_get(struct tty_struct *tty,
 	atomic_inc(&buf->count);
 	/* Fall through */
  out:
-	spin_unlock_irq(&current->sighand->siglock);
+	spin_unlock_irqrestore(&current->sighand->siglock, flags);
 	if (buf2)
 		tty_audit_buf_free(buf2);
 	return buf;
@@ -317,16 +322,17 @@ void tty_audit_add_data(struct tty_struct *tty, unsigned char *data,
 void tty_audit_push(struct tty_struct *tty)
 {
 	struct tty_audit_buf *buf;
+	unsigned long flags;
 
-	spin_lock_irq(&current->sighand->siglock);
+	spin_lock_irqsave(&current->sighand->siglock, flags);
 	if (likely(!current->signal->audit_tty)) {
-		spin_unlock_irq(&current->sighand->siglock);
+		spin_unlock_irqrestore(&current->sighand->siglock, flags);
 		return;
 	}
 	buf = current->signal->tty_audit_buf;
 	if (buf)
 		atomic_inc(&buf->count);
-	spin_unlock_irq(&current->sighand->siglock);
+	spin_unlock_irqrestore(&current->sighand->siglock, flags);
 
 	if (buf) {
 		int major, minor;

kernel/audit.c

@@ -804,10 +804,11 @@ 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 = current;
+		unsigned long flags;
 
-		spin_lock_irq(&tsk->sighand->siglock);
+		spin_lock_irqsave(&tsk->sighand->siglock, flags);
 		s.enabled = tsk->signal->audit_tty != 0;
-		spin_unlock_irq(&tsk->sighand->siglock);
+		spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
 
 		audit_send_reply(NETLINK_CB(skb).portid, seq,
 				 AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
@@ -816,6 +817,7 @@ 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 = current;
+		unsigned long flags;
 
 		if (nlh->nlmsg_len < sizeof(struct audit_tty_status))
 			return -EINVAL;
@@ -823,9 +825,9 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		if (s->enabled != 0 && s->enabled != 1)
 			return -EINVAL;
 
-		spin_lock_irq(&tsk->sighand->siglock);
+		spin_lock_irqsave(&tsk->sighand->siglock, flags);
 		tsk->signal->audit_tty = s->enabled != 0;
-		spin_unlock_irq(&tsk->sighand->siglock);
+		spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
 		break;
 	}
 	default: