Commit ef8eecbd authored by Johan Hovold's avatar Johan Hovold Committed by Khalid Elmously

USB: serial: iuu_phoenix: fix memory corruption

BugLink: https://bugs.launchpad.net/bugs/1888690

commit e7b931be 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: 5fcf62b0 ("tty: iuu_phoenix: fix locking.")
Cc: stable <stable@vger.kernel.org>     # 2.6.31
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
Signed-off-by: default avatarKhalid Elmously <khalid.elmously@canonical.com>
parent 33a91ae8
...@@ -717,14 +717,16 @@ static int iuu_uart_write(struct tty_struct *tty, struct usb_serial_port *port, ...@@ -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); struct iuu_private *priv = usb_get_serial_port_data(port);
unsigned long flags; unsigned long flags;
if (count > 256)
return -ENOMEM;
spin_lock_irqsave(&priv->lock, flags); spin_lock_irqsave(&priv->lock, flags);
count = min(count, 256 - priv->writelen);
if (count == 0)
goto out;
/* fill the buffer */ /* fill the buffer */
memcpy(priv->writebuf + priv->writelen, buf, count); memcpy(priv->writebuf + priv->writelen, buf, count);
priv->writelen += count; priv->writelen += count;
out:
spin_unlock_irqrestore(&priv->lock, flags); spin_unlock_irqrestore(&priv->lock, flags);
return count; return count;
......
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