Commit 0ab90ddb authored Mar 06, 2017 by Johan Hovold Committed by Greg Kroah-Hartman Mar 18, 2017

USB: serial: safe_serial: fix information leak in completion handler



commit 8c76d7cd520ebffc1ea9ea0850d87a224a50c7f2 upstream.

Add missing sanity check to the bulk-in completion handler to avoid an
integer underflow that could be triggered by a malicious device.

This avoids leaking up to 56 bytes from after the URB transfer buffer to
user space.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 24db1c5a

drivers/usb/serial/safe_serial.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -200,6 +200,11 @@ static void safe_process_read_urb(struct urb *urb)
		if (!safe)
		goto out;

		if (length < 2) {
		dev_err(&port->dev, "malformed packet\n");
		return;
		}

		fcs = fcs_compute10(data, length, CRC10_INITFCS);
		if (fcs) {
		dev_err(&port->dev, "%s - bad CRC %x\n", __func__, fcs);