From: Johan Hovold johan@kernel.org
commit e7b931bee739e8a77ae216e613d3b99342b6dec0 upstream.
The driver would happily overwrite its write buffer with user data in 256 byte increments due to a removed buffer-space sanity check.
Fixes: 5fcf62b0f1f2 ("tty: iuu_phoenix: fix locking.") Cc: stable stable@vger.kernel.org # 2.6.31 Signed-off-by: Johan Hovold johan@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/usb/serial/iuu_phoenix.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
--- a/drivers/usb/serial/iuu_phoenix.c +++ b/drivers/usb/serial/iuu_phoenix.c @@ -704,14 +704,16 @@ static int iuu_uart_write(struct tty_str struct iuu_private *priv = usb_get_serial_port_data(port); unsigned long flags;
- if (count > 256) - return -ENOMEM; - spin_lock_irqsave(&priv->lock, flags);
+ count = min(count, 256 - priv->writelen); + if (count == 0) + goto out; + /* fill the buffer */ memcpy(priv->writebuf + priv->writelen, buf, count); priv->writelen += count; +out: spin_unlock_irqrestore(&priv->lock, flags);
return count;