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From:   Johan Hovold <johan@kernel.org>
To:     Marc Kleine-Budde <mkl@pengutronix.de>
Cc:     Wolfgang Grandegger <wg@grandegger.com>, linux-can@vger.kernel.org,
        netdev@vger.kernel.org, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org, Johan Hovold <johan@kernel.org>,
        stable <stable@vger.kernel.org>,
        Jimmy Assarsson <extja@kvaser.com>,
        Christer Beskow <chbe@kvaser.com>,
        Nicklas Johansson <extnj@kvaser.com>,
        Martin Henriksson <mh@kvaser.com>
Subject: [PATCH 1/2] can: kvaser_usb: fix interface sanity check
Date:   Tue, 10 Dec 2019 12:32:30 +0100
Message-Id: <20191210113231.3797-2-johan@kernel.org>
In-Reply-To: <20191210113231.3797-1-johan@kernel.org>
References: <20191210113231.3797-1-johan@kernel.org>
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Sender: linux-kernel-owner@vger.kernel.org
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Make sure to use the current alternate setting when verifying the
interface descriptors to avoid binding to an invalid interface.

Failing to do so could cause the driver to misbehave or trigger a WARN()
in usb_submit_urb() that kernels with panic_on_warn set would choke on.

Fixes: aec5fb2268b7 ("can: kvaser_usb: Add support for Kvaser USB hydra family")
Cc: stable <stable@vger.kernel.org>     # 4.19
Cc: Jimmy Assarsson <extja@kvaser.com>
Cc: Christer Beskow <chbe@kvaser.com>
Cc: Nicklas Johansson <extnj@kvaser.com>
Cc: Martin Henriksson <mh@kvaser.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/net/can/usb/kvaser_usb/kvaser_usb_hydra.c | 2 +-
 drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/usb/kvaser_usb/kvaser_usb_hydra.c b/drivers/net/can/usb/kvaser_usb/kvaser_usb_hydra.c
index 5fc0be564274..7ab87a758754 100644
--- a/drivers/net/can/usb/kvaser_usb/kvaser_usb_hydra.c
+++ b/drivers/net/can/usb/kvaser_usb/kvaser_usb_hydra.c
@@ -1590,7 +1590,7 @@ static int kvaser_usb_hydra_setup_endpoints(struct kvaser_usb *dev)
 	struct usb_endpoint_descriptor *ep;
 	int i;
 
-	iface_desc = &dev->intf->altsetting[0];
+	iface_desc = dev->intf->cur_altsetting;
 
 	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 		ep = &iface_desc->endpoint[i].desc;
diff --git a/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c b/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c
index 07d2f3aa2c02..1c794bb443e1 100644
--- a/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c
+++ b/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c
@@ -1310,7 +1310,7 @@ static int kvaser_usb_leaf_setup_endpoints(struct kvaser_usb *dev)
 	struct usb_endpoint_descriptor *endpoint;
 	int i;
 
-	iface_desc = &dev->intf->altsetting[0];
+	iface_desc = dev->intf->cur_altsetting;
 
 	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 		endpoint = &iface_desc->endpoint[i].desc;
-- 
2.24.0