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authorIan Abbott <abbotti@mev.co.uk>2017-03-08 16:02:59 +0000
committerJohan Hovold <johan@kernel.org>2017-03-13 16:55:40 +0100
commitdb9240662a44e1b7781c8dbf35631bcec7a369c6 (patch)
treeb1309bbd05ebb4bcc9288a109d24038243f107c2 /drivers/usb/serial/ftdi_sio.c
parent7e1e6ceda3f07a40445ae1c4ac5549a899d5e252 (diff)
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op-kernel-dev-db9240662a44e1b7781c8dbf35631bcec7a369c6.tar.gz
USB: serial: ftdi_sio: only allow valid latency timer values
Valid latency timer values are between 1 ms and 255 ms in 1 ms steps. The store function for the "latency_timer" device attribute currently allows any value, although only the lower 16 bits will be sent to the device, and the device only stores the lower 8 bits. The hardware appears to accept the (invalid) value 0 and treats it the same as 1 (resulting in a latency of 1 ms). Change the latency_timer_store() function to accept only the values 0 to 255, returning an error -EINVAL for out-of-range values. Call kstrtou8() to parse the integer instead of the obsolete simple_strtoul(). Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Johan Hovold <johan@kernel.org>
Diffstat (limited to 'drivers/usb/serial/ftdi_sio.c')
-rw-r--r--drivers/usb/serial/ftdi_sio.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index 2b9b511..b774f9d 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -1716,9 +1716,12 @@ static ssize_t latency_timer_store(struct device *dev,
{
struct usb_serial_port *port = to_usb_serial_port(dev);
struct ftdi_private *priv = usb_get_serial_port_data(port);
- int v = simple_strtoul(valbuf, NULL, 10);
+ u8 v;
int rv;
+ if (kstrtou8(valbuf, 10, &v))
+ return -EINVAL;
+
priv->latency = v;
rv = write_latency_timer(port);
if (rv < 0)
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