USB: iowarrior: fix NULL-deref at probe

Make sure to check for the required interrupt-in endpoint to avoid
dereferencing a NULL-pointer should a malicious device lack such an
endpoint.

Note that a fairly recent change purported to fix this issue, but added
an insufficient test on the number of endpoints only, a test which can
now be removed.

Fixes: 4ec0ef3a8212 ("USB: iowarrior: fix oops with malicious USB descriptors")
Fixes: 946b960d13c1 ("USB: add driver for iowarrior devices.")
Cc: stable <stable@vger.kernel.org>	# 2.6.21
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 7 insertions, 6 deletions

diff --git a/drivers/usb/misc/iowarrior.c b/drivers/usb/misc/iowarrior.c
index 095778ff984d..3ad058cbe6ca 100644
--- a/drivers/usb/misc/iowarrior.c
+++ b/drivers/usb/misc/iowarrior.c
@@ -781,12 +781,6 @@ static int iowarrior_probe(struct usb_interface *interface,
         iface_desc = interface->cur_altsetting;
         dev->product_id = le16_to_cpu(udev->descriptor.idProduct);
 
-        if (iface_desc->desc.bNumEndpoints < 1) {
-                dev_err(&interface->dev, "Invalid number of endpoints\n");
-                retval = -EINVAL;
-                goto error;
-        }
-
         /* set up the endpoint information */
         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
                 endpoint = &iface_desc->endpoint[i].desc;
@@ -797,6 +791,13 @@ static int iowarrior_probe(struct usb_interface *interface,
                         /* this one will match for the IOWarrior56 only */
                         dev->int_out_endpoint = endpoint;
         }
+
+        if (!dev->int_in_endpoint) {
+                dev_err(&interface->dev, "no interrupt-in endpoint found\n");
+                retval = -ENODEV;
+                goto error;
+        }
+
         /* we have to check the report_size often, so remember it in the endianness suitable for our machine */
         dev->report_size = usb_endpoint_maxp(dev->int_in_endpoint);
         if ((dev->interface->cur_altsetting->desc.bInterfaceNumber == 0) &&