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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org, Denis Kirjanov <kda@linux-powerpc.org>,
        "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
        "Johan Hovold" <johan@kernel.org>
Date:   Fri, 24 Apr 2020 00:05:14 +0100
Message-ID: <lsq.1587683028.325175386@decadent.org.uk>
Subject: [PATCH 3.16 087/245] USB: idmouse: fix interface sanity checks
In-Reply-To: <lsq.1587683027.831233700@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
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3.16.83-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Johan Hovold <johan@kernel.org>

commit 59920635b89d74b9207ea803d5e91498d39e8b69 upstream.

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: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20191210112601.3561-4-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/usb/misc/idmouse.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/usb/misc/idmouse.c
+++ b/drivers/usb/misc/idmouse.c
@@ -342,7 +342,7 @@ static int idmouse_probe(struct usb_inte
 	int result;
 
 	/* check if we have gotten the data or the hid interface */
-	iface_desc = &interface->altsetting[0];
+	iface_desc = interface->cur_altsetting;
 	if (iface_desc->desc.bInterfaceClass != 0x0A)
 		return -ENODEV;