[PATCH 3.12 087/142] USB: wusbcore: fix NULL-deref at probe

[Jiri Slaby]

From: Johan Hovold <johan@xxxxxxxxxx>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit 03ace948a4eb89d1cf51c06afdfc41ebca5fdb27 upstream.

Make sure to check the number of endpoints to avoid dereferencing a
NULL-pointer or accessing memory beyond the endpoint array should a
malicious device lack the expected endpoints.

This specifically fixes the NULL-pointer dereference when probing HWA HC
devices.

Fixes: df3654236e31 ("wusb: add the Wire Adapter (WA) core")
Cc: Inaky Perez-Gonzalez <inaky.perez-gonzalez@xxxxxxxxx>
Cc: David Vrabel <david.vrabel@xxxxxxx>
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
 drivers/usb/wusbcore/wa-hc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/wusbcore/wa-hc.c b/drivers/usb/wusbcore/wa-hc.c
index a09b65ebd9bb..2bb0fd3f3423 100644
--- a/drivers/usb/wusbcore/wa-hc.c
+++ b/drivers/usb/wusbcore/wa-hc.c
@@ -38,6 +38,9 @@ int wa_create(struct wahc *wa, struct usb_interface *iface)
 	int result;
 	struct device *dev = &iface->dev;
 
+	if (iface->cur_altsetting->desc.bNumEndpoints < 3)
+		return -ENODEV;
+
 	result = wa_rpipes_create(wa);
 	if (result < 0)
 		goto error_rpipes_create;
-- 
2.12.2