From a78ef8861986cfe1ea61fa03caaa27e1f817c974 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Fri, 6 Jan 2017 19:15:18 +0100 Subject: [PATCH] USB: serial: ch341: fix control-message error handling commit 2d5a9c72d0c4ac73cf97f4b7814ed6c44b1e49ae upstream. A short control transfer would currently fail to be detected, something which could lead to stale buffer data being used as valid input. Check for short transfers, and make sure to log any transfer errors. Note that this also avoids leaking heap data to user space (TIOCMGET) and the remote device (break control). Fixes: 6ce76104781a ("USB: Driver for CH341 USB-serial adaptor") Signed-off-by: Johan Hovold [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- drivers/usb/serial/ch341.c | 34 ++++++++++++++++++++++------------ 1 file changed, 22 insertions(+), 12 deletions(-) diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c index 22e748aa0b17..d50a6a696a8d 100644 --- a/drivers/usb/serial/ch341.c +++ b/drivers/usb/serial/ch341.c @@ -115,6 +115,8 @@ static int ch341_control_out(struct usb_device *dev, u8 request, r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request, USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT, value, index, NULL, 0, DEFAULT_TIMEOUT); + if (r < 0) + dev_err(&dev->dev, "failed to send control message: %d\n", r); return r; } @@ -130,7 +132,20 @@ static int ch341_control_in(struct usb_device *dev, r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request, USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, value, index, buf, bufsize, DEFAULT_TIMEOUT); - return r; + if (r < bufsize) { + if (r >= 0) { + dev_err(&dev->dev, + "short control message received (%d < %u)\n", + r, bufsize); + r = -EIO; + } + + dev_err(&dev->dev, "failed to receive control message: %d\n", + r); + return r; + } + + return 0; } static int ch341_set_baudrate_lcr(struct usb_device *dev, @@ -184,9 +199,9 @@ static int ch341_set_handshake(struct usb_device *dev, u8 control) static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv) { + const unsigned int size = 2; char *buffer; int r; - const unsigned size = 8; unsigned long flags; dbg("ch341_get_status()"); @@ -199,15 +214,10 @@ static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv) if (r < 0) goto out; - /* setup the private status if available */ - if (r == 2) { - r = 0; - spin_lock_irqsave(&priv->lock, flags); - priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT; - priv->multi_status_change = 0; - spin_unlock_irqrestore(&priv->lock, flags); - } else - r = -EPROTO; + spin_lock_irqsave(&priv->lock, flags); + priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT; + priv->multi_status_change = 0; + spin_unlock_irqrestore(&priv->lock, flags); out: kfree(buffer); return r; @@ -217,9 +227,9 @@ out: kfree(buffer); static int ch341_configure(struct usb_device *dev, struct ch341_private *priv) { + const unsigned int size = 2; char *buffer; int r; - const unsigned size = 8; dbg("ch341_configure()"); -- 2.39.2