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 aaca4fe38486a03de36340a07a376340278dd52b..1f8362d5e3b970b2bfa4544538f6d88378b312ec 100644 (file)
--- a/drivers/tty/serial/serial_txx9.c
+++ b/drivers/tty/serial/serial_txx9.c
@@ -644,6 +644,8 @@ 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;
        }