[PATCH 4.9 34/44] USB: iowarrior: fix NULL-deref at probe

Greg Kroah-Hartman
2017-03-16T14:55:33Z

From: Johan Hovold <johan@kernel.org>

commit b7321e81fc369abe353cf094d4f0dc2fe11ab95f upstream.

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.")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/usb/misc/iowarrior.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

--- a/drivers/usb/misc/iowarrior.c
+++ b/drivers/usb/misc/iowarrior.c
@@ -781,12 +781,6 @@ static int iowarrior_probe(struct usb_in
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_in
/* 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) &&