From: Johan Hovold <johan@kernel.org>
Date: Wed, 15 Jul 2020 09:02:45 +0000 (+0200)
Subject: USB: serial: iuu_phoenix: fix memory corruption
X-Git-Tag: v5.8-rc6~6^2^2
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=e7b931bee739e8a77ae216e613d3b99342b6dec0;p=users%2Fjedix%2Flinux-maple.git
USB: serial: iuu_phoenix: fix memory corruption
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>
---
diff --git a/drivers/usb/serial/iuu_phoenix.c b/drivers/usb/serial/iuu_phoenix.c
index d5bff69b1769..b8dfeb4fb2ed 100644
--- a/drivers/usb/serial/iuu_phoenix.c
+++ b/drivers/usb/serial/iuu_phoenix.c
@@ -697,14 +697,16 @@ 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;