From: Johan Hovold Date: Wed, 15 Jul 2020 09:02:45 +0000 (+0200) Subject: USB: serial: iuu_phoenix: fix memory corruption X-Git-Tag: v4.9.231~19 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=df5228f1071e1d98408532e7d6877e0c512dfd56;p=platform%2Fkernel%2Flinux-amlogic.git USB: serial: iuu_phoenix: fix memory corruption 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 # 2.6.31 Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/serial/iuu_phoenix.c b/drivers/usb/serial/iuu_phoenix.c index d57fb5199218..d6ac1f472b77 100644 --- a/drivers/usb/serial/iuu_phoenix.c +++ b/drivers/usb/serial/iuu_phoenix.c @@ -717,14 +717,16 @@ static int iuu_uart_write(struct tty_struct *tty, struct usb_serial_port *port, 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;