[PATCH net] net: usb: pegasus: validate USB endpoints

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

The pegasus driver should validate that the device it is probing has the
proper number and types of USB endpoints it is expecting before it binds
to it.  If a malicious device were to not have the same urbs the driver
will crash later on when it blindly accesses these endpoints.

Cc: Petko Manolov <petkan@nucleusys.com>
Cc: stable <stable@kernel.org>
Assisted-by: gkh_clanker_2000
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/usb/pegasus.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/net/usb/pegasus.c b/drivers/net/usb/pegasus.c
index 4f539b5d509a..94c17fed0bd4 100644
--- a/drivers/net/usb/pegasus.c
+++ b/drivers/net/usb/pegasus.c
@@ -801,8 +801,19 @@ static void unlink_all_urbs(pegasus_t *pegasus)
 
 static int alloc_urbs(pegasus_t *pegasus)
 {
+	static const u8 bulk_ep_addr[] = {
+		1 | USB_DIR_IN,
+		2 | USB_DIR_OUT,
+		0};
+	static const u8 int_ep_addr[] = {
+		3 | USB_DIR_IN,
+		0};
 	int res = -ENOMEM;
 
+	if (!usb_check_bulk_endpoints(pegasus->intf, bulk_ep_addr) ||
+	    !usb_check_int_endpoints(pegasus->intf, int_ep_addr))
+		return -ENODEV;
+
 	pegasus->rx_urb = usb_alloc_urb(0, GFP_KERNEL);
 	if (!pegasus->rx_urb) {
 		return res;
@@ -1143,6 +1154,7 @@ static int pegasus_probe(struct usb_interface *intf,
 
 	pegasus = netdev_priv(net);
 	pegasus->dev_index = dev_index;
+	pegasus->intf = intf;
 
 	res = alloc_urbs(pegasus);
 	if (res < 0) {
@@ -1154,7 +1166,6 @@ static int pegasus_probe(struct usb_interface *intf,
 
 	INIT_DELAYED_WORK(&pegasus->carrier_check, check_carrier);
 
-	pegasus->intf = intf;
 	pegasus->usb = dev;
 	pegasus->net = net;
 
-- 
2.53.0