usbtmc: more sanity checking for packet size

A malicious device can make the driver divide ny zero
with a nonsense maximum packet size.

Signed-off-by: Oliver Neukum <oneukum@suse.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20190820092826.17694-1-oneukum@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
index 4942122b2346d4804f2279fa8eb033296e1dd25b..36858ddd8d9bb2d7b383c9672a9c2c64ee82ecc4 100644 (file)
--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -2362,8 +2362,11 @@ static int usbtmc_probe(struct usb_interface *intf,
                goto err_put;
        }
 
+       retcode = -EINVAL;
        data->bulk_in = bulk_in->bEndpointAddress;
        data->wMaxPacketSize = usb_endpoint_maxp(bulk_in);
+       if (!data->wMaxPacketSize)
+               goto err_put;
        dev_dbg(&intf->dev, "Found bulk in endpoint at %u\n", data->bulk_in);
 
        data->bulk_out = bulk_out->bEndpointAddress;