From 3cdc94638746eab168accf0f808a83e59fe1ca67 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Mon, 6 Mar 2017 17:36:41 +0100 Subject: [PATCH] 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: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/safe_serial.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/usb/serial/safe_serial.c b/drivers/usb/serial/safe_serial.c index b2dff0f14743..236ea43f7815 100644 --- a/drivers/usb/serial/safe_serial.c +++ b/drivers/usb/serial/safe_serial.c @@ -205,6 +205,11 @@ 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); -- 2.20.1