serial: txx9: Don't allow CS5-6

[ Upstream commit 79ac88655dc0551e3571ad16bdabdbe65d61553e ]

Only CS7 and CS8 are supported but CSIZE is not sanitized with
CS5 or CS6 to CS8.

Set CSIZE correctly so that userspace knows the effective value.
Incorrect CSIZE also results in miscalculation of the frame bits in
tty_get_char_size() or in its predecessor where the roughly the same
code is directly within uart_update_timeout().

Fixes: 1da177e4c3f4 (Linux-2.6.12-rc2)
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220519081808.3776-5-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/tty/serial/serial_txx9.c b/drivers/tty/serial/serial_txx9.c
index ba77e72057a96634208697eac4a6aefe07858407..5d41884f5012e9515b8766f26ba1d128a3c96342 100644 (file)
--- a/drivers/tty/serial/serial_txx9.c
+++ b/drivers/tty/serial/serial_txx9.c
@@ -652,6 +652,8 @@ serial_txx9_set_termios(struct uart_port *port, struct ktermios *termios,
        case CS6:       /* not supported */
        case CS8:
                cval |= TXX9_SILCR_UMODE_8BIT;
+               termios->c_cflag &= ~CSIZE;
+               termios->c_cflag |= CS8;
                break;
        }