serial: rda-uart: Don't allow CS5-6

[ Upstream commit 098333a9c7d12bb3ce44c82f08b4d810c44d31b0 ]

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

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: c10b13325ced (tty: serial: Add RDA8810PL UART driver)
Cc: Manivannan Sadhasivam <mani@kernel.org>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220519081808.3776-4-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/rda-uart.c b/drivers/tty/serial/rda-uart.c
index d550d8fa2fabf3289c90ebab28207b34ea5e67d1..a8fe1c3ebcd988e1474eafbbb3b57e9120884da9 100644 (file)
--- a/drivers/tty/serial/rda-uart.c
+++ b/drivers/tty/serial/rda-uart.c
@@ -262,6 +262,8 @@ static void rda_uart_set_termios(struct uart_port *port,
                fallthrough;
        case CS7:
                ctrl &= ~RDA_UART_DBITS_8;
+               termios->c_cflag &= ~CSIZE;
+               termios->c_cflag |= CS7;
                break;
        default:
                ctrl |= RDA_UART_DBITS_8;