[PATCH 4.9 80/92] tty: wipe buffer.

[Greg Kroah-Hartman]

4.9-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 |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -458,6 +458,8 @@ int tty_ldisc_receive_buf(struct tty_ldi
 		if (count && ld->ops->receive_buf)
 			ld->ops->receive_buf(ld->tty, p, f, count);
 	}
+	if (count > 0)
+		memset(p, 0, count);
 	return count;
 }
 EXPORT_SYMBOL_GPL(tty_ldisc_receive_buf);