[PATCH 2/3] USB: serial: mct_u232: fix big-endian baud-rate handling

[PATCH 2/3] USB: serial: mct_u232: fix big-endian baud-rate handling

[Johan Hovold]

Drop erroneous cpu_to_le32 when setting the baud rate, something which
corrupted the divisor on big-endian hosts.

Found using sparse:

	warning: incorrect type in argument 1 (different base types)
	    expected unsigned int [unsigned] [usertype] val
	    got restricted __le32 [usertype] <noident>

Fixes: af2ac1a091bc ("USB: serial mct_usb232: move DMA buffers to heap")
Cc: stable <stable@vger.kernel.org>     # 2.6.34
Cc: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/mct_u232.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/serial/mct_u232.c b/drivers/usb/serial/mct_u232.c
index edbc81f205c2..70f346f1aa86 100644
--- a/drivers/usb/serial/mct_u232.c
+++ b/drivers/usb/serial/mct_u232.c
@@ -189,7 +189,7 @@ static int mct_u232_set_baud_rate(struct tty_struct *tty,
 		return -ENOMEM;
 
 	divisor = mct_u232_calculate_baud_rate(serial, value, &speed);
-	put_unaligned_le32(cpu_to_le32(divisor), buf);
+	put_unaligned_le32(divisor, buf);
 	rc = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
 				MCT_U232_SET_BAUD_RATE_REQUEST,
 				MCT_U232_SET_REQUEST_TYPE,
-- 
2.13.0

[PATCH 3/3] USB: serial: io_ti: fix div-by-zero in set_termios

[Johan Hovold]

Fix a division-by-zero in set_termios when debugging is enabled and a
high-enough speed has been requested so that the divisor value becomes
zero.

Instead of just fixing the offending debug statement, cap the baud rate
at the base as a zero divisor value also appears to crash the firmware.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable <stable@vger.kernel.org>     # 2.6.12
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/io_ti.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/serial/io_ti.c b/drivers/usb/serial/io_ti.c
index 87798e625d6c..6cefb9cb133d 100644
--- a/drivers/usb/serial/io_ti.c
+++ b/drivers/usb/serial/io_ti.c
@@ -2336,8 +2336,11 @@ static void change_port_settings(struct tty_struct *tty,
 	if (!baud) {
 		/* pick a default, any default... */
 		baud = 9600;
-	} else
+	} else {
+		/* Avoid a zero divisor. */
+		baud = min(baud, 461550);
 		tty_encode_baud_rate(tty, baud, baud);
+	}
 
 	edge_port->baud_rate = baud;
 	config->wBaudRate = (__u16)((461550L + baud/2) / baud);
-- 
2.13.0

Re: [PATCH 2/3] USB: serial: mct_u232: fix big-endian baud-rate handling

[Pete Zaitcev]

On Thu, 11 May 2017 11:41:20 +0200
Johan Hovold <johan@kernel.org> wrote:

> Drop erroneous cpu_to_le32 when setting the baud rate, something which
> corrupted the divisor on big-endian hosts.

> +++ b/drivers/usb/serial/mct_u232.c
> @@ -189,7 +189,7 @@ static int mct_u232_set_baud_rate(struct tty_struct *tty,
>  	divisor = mct_u232_calculate_baud_rate(serial, value, &speed);
> -	put_unaligned_le32(cpu_to_le32(divisor), buf);
> +	put_unaligned_le32(divisor, buf);
>  	rc = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),

Acked-By: Pete Zaitcev <zaitcev@yahoo.com>

-- Pete