From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 66D03C433E2 for ; Thu, 17 Sep 2020 19:57:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 48CBC20725 for ; Thu, 17 Sep 2020 19:57:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727550AbgIQOny (ORCPT ); Thu, 17 Sep 2020 10:43:54 -0400 Received: from aibo.runbox.com ([91.220.196.211]:55470 "EHLO aibo.runbox.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727648AbgIQOmS (ORCPT ); Thu, 17 Sep 2020 10:42:18 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=runbox.com; s=selector2; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To :Message-Id:Date:Subject:Cc:To:From; bh=WaCu4zldHM3wFml3XoeYbHVyOElXbVex+B6UOeOoYQs=; b=K5nbWtU2dkwkGPzspMmSTpOjNX lXlAcg9cV3ApcaEGvrjC/EaeltW8ObTwpXDVerxkdpOMJFeHdnaJSkZwzGW0gr3Fm3YSRljTAohW2 H6K+q/asalUdLPBBh9zmyqt+1rDaieydvu8fD4IJPy2RMzNuVa4BOLf9HZsTpixmh6TgALK3aIqPq bYd5tMkGTS0+gB2/gyuK3nD7WSrLhFKc0OKW4/EkXTb/qj4cWj6RagaVXI26mGVa4AGLNQttj3Dot nAM0gtLKF3aq2NQBGa9f5uar92GpNBZVx26DOLyBoa5a6n5IOPOPv9Hirnq+wazpNNSAhMFkCKHNV /lqiI7QQ==; Received: from [10.9.9.72] (helo=submission01.runbox) by mailtransmit03.runbox with esmtp (Exim 4.86_2) (envelope-from ) id 1kIv6z-0007ku-MD; Thu, 17 Sep 2020 16:42:13 +0200 Received: by submission01.runbox with esmtpsa [Authenticated alias (536975)] (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) id 1kIv6m-0002ee-8o; Thu, 17 Sep 2020 16:42:00 +0200 From: "M. Vefa Bicakci" To: linux-usb@vger.kernel.org Cc: "M. Vefa Bicakci" , Andrey Konovalov , stable@vger.kernel.org, Greg Kroah-Hartman , Alan Stern , Bastien Nocera , syzkaller@googlegroups.com Subject: [PATCH 1/3] usbcore/driver: Fix specific driver selection Date: Thu, 17 Sep 2020 17:41:49 +0300 Message-Id: <20200917144151.355848-1-m.v.b@runbox.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org This commit resolves a bug in the selection/discovery of more specific USB device drivers for devices that are currently bound to generic USB device drivers. The bug is in the logic that determines whether a device currently bound to a generic USB device driver should be re-probed by a more specific USB device driver or not. The code in __usb_bus_reprobe_drivers() used to have the following lines: if (usb_device_match_id(udev, new_udriver->id_table) == NULL && (!new_udriver->match || new_udriver->match(udev) != 0)) return 0; ret = device_reprobe(dev); As the reader will notice, the code checks whether the USB device in consideration matches the identifier table (id_table) of a specific USB device_driver (new_udriver), followed by a similar check, but this time with the USB device driver's match function. However, the match function's return value is not checked correctly. When match() returns zero, it means that the specific USB device driver is *not* applicable to the USB device in question, but the code then goes on to reprobe the device with the new USB device driver under consideration. All this to say, the logic is inverted. This bug was found by code inspection and instrumentation after Andrey Konovalov's report indicating USB/IP subsystem's misbehaviour with the generic USB device driver matching code. Reported-by: Andrey Konovalov Fixes: d5643d2249 ("USB: Fix device driver race") Link: https://lore.kernel.org/linux-usb/CAAeHK+zOrHnxjRFs=OE8T=O9208B9HP_oo8RZpyVOZ9AJ54pAA@mail.gmail.com/ Cc: # 5.8 Cc: Greg Kroah-Hartman Cc: Alan Stern Cc: Bastien Nocera Cc: Signed-off-by: M. Vefa Bicakci --- drivers/usb/core/driver.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c index c976ea9f9582..950044a6e77f 100644 --- a/drivers/usb/core/driver.c +++ b/drivers/usb/core/driver.c @@ -924,7 +924,7 @@ static int __usb_bus_reprobe_drivers(struct device *dev, void *data) udev = to_usb_device(dev); if (usb_device_match_id(udev, new_udriver->id_table) == NULL && - (!new_udriver->match || new_udriver->match(udev) != 0)) + (!new_udriver->match || new_udriver->match(udev) == 0)) return 0; ret = device_reprobe(dev); base-commit: 871e6496207c6aa94134448779c77631a11bfa2e -- 2.26.2