Patch "serial: sifive: Sanitize CSIZE and c_iflag" has been added to the 5.18-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    serial: sifive: Sanitize CSIZE and c_iflag

to the 5.18-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     serial-sifive-sanitize-csize-and-c_iflag.patch
and it can be found in the queue-5.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 7999b43c2ceca48b7972fb72b0857da2b6e960a8
Author: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
Date:   Thu May 19 11:18:05 2022 +0300

    serial: sifive: Sanitize CSIZE and c_iflag
    
    [ Upstream commit c069d2756c01ed36121fae6a42c14fdf1325c71d ]
    
    Only CS8 is supported but CSIZE was not sanitized 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().
    
    Similarly, INPCK, PARMRK, and BRKINT are reported textually unsupported
    but were not cleared in termios c_iflag which is the machine-readable
    format.
    
    Fixes: 45c054d0815b (tty: serial: add driver for the SiFive UART)
    Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
    Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
    Link: https://lore.kernel.org/r/20220519081808.3776-7-ilpo.jarvinen@xxxxxxxxxxxxxxx
    Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/tty/serial/sifive.c b/drivers/tty/serial/sifive.c
index 6140166b7ed5..776aec6516c4 100644
--- a/drivers/tty/serial/sifive.c
+++ b/drivers/tty/serial/sifive.c
@@ -666,12 +666,16 @@ static void sifive_serial_set_termios(struct uart_port *port,
 	int rate;
 	char nstop;
 
-	if ((termios->c_cflag & CSIZE) != CS8)
+	if ((termios->c_cflag & CSIZE) != CS8) {
 		dev_err_once(ssp->port.dev, "only 8-bit words supported\n");
+		termios->c_cflag &= ~CSIZE;
+		termios->c_cflag |= CS8;
+	}
 	if (termios->c_iflag & (INPCK | PARMRK))
 		dev_err_once(ssp->port.dev, "parity checking not supported\n");
 	if (termios->c_iflag & BRKINT)
 		dev_err_once(ssp->port.dev, "BREAK detection not supported\n");
+	termios->c_iflag &= ~(INPCK|PARMRK|BRKINT);
 
 	/* Set number of stop bits */
 	nstop = (termios->c_cflag & CSTOPB) ? 2 : 1;