[PATCH 4.14 089/100] tty: wipe buffer.

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>

commit c9a8e5fce009e3c601a43c49ea9dbcb25d1ffac5 upstream.

After we are done with the tty buffer, zero it out.

Reported-by: aszlig <aszlig@xxxxxxxxx>
Tested-by: Milan Broz <gmazyland@xxxxxxxxx>
Tested-by: Daniel Zatovic <daniel.zatovic@xxxxxxxxx>
Tested-by: aszlig <aszlig@xxxxxxxxx>
Cc: Willy Tarreau <w@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/tty/tty_buffer.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -467,11 +467,15 @@ receive_buf(struct tty_port *port, struc
 {
 	unsigned char *p = char_buf_ptr(head, head->read);
 	char	      *f = NULL;
+	int n;
 
 	if (~head->flags & TTYB_NORMAL)
 		f = flag_buf_ptr(head, head->read);
 
-	return port->client_ops->receive_buf(port, p, f, count);
+	n = port->client_ops->receive_buf(port, p, f, count);
+	if (n > 0)
+		memset(p, 0, n);
+	return n;
 }
 
 /**