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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 45BF5C43334 for ; Thu, 9 Jun 2022 14:00:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236439AbiFIOAU (ORCPT ); Thu, 9 Jun 2022 10:00:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37242 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230094AbiFIOAS (ORCPT ); Thu, 9 Jun 2022 10:00:18 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 09AC1B31; Thu, 9 Jun 2022 07:00:17 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id C1A96B82D5B; Thu, 9 Jun 2022 14:00:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8C9FAC34114; Thu, 9 Jun 2022 14:00:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1654783214; bh=LmGPGQgFlXDp39gkuaUh/QQ94CuUMZoIes/TMms8Jfc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=F22F5K/aPgI/wT/JwFq3XZhGIWh9x6u3peG/NtDCkXeoOvHm2BToOMwNFhQFopdwm +7atn6OwSfogpGGrhsA082Fk807mMpFGQ0olpsjEk0dqSBniHrLDK/U67dTVW/DFnF 7lWOJGc7L5f7Yed98S6MvagMr2R9+PpVHvHrkvB+hB9vjP6B4E4JpmPIk3l4itdrZq vLqMb/sEfG6uaPiAQ1DtQqipPWyETU49oMR6z5WqbZ6YNYgOwM0y3a2dyfZIOqVmXj CCs2220Q22QLKKAWceh5PpRuVhDqVH0KDQEIqhJSs3bEM69HajO1jvV2EEUrWdnAbx JEkAVA26cc9VA== Received: from johan by xi.lan with local (Exim 4.94.2) (envelope-from ) id 1nzIhm-0005EB-Ke; Thu, 09 Jun 2022 16:00:10 +0200 Date: Thu, 9 Jun 2022 16:00:10 +0200 From: Johan Hovold To: Dongliang Mu Cc: Dongliang Mu , Mauro Carvalho Chehab , gushengxian , Hans Verkuil , Oliver Neukum , Sean Young , Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux-kernel Subject: Re: [PATCH] media: flexcop-usb: fix sanity check of bNumEndpoints Message-ID: References: <20220602055027.849014-1-dzm91@hust.edu.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On Thu, Jun 09, 2022 at 09:42:15AM +0800, Dongliang Mu wrote: > On Thu, Jun 2, 2022 at 2:45 PM Johan Hovold wrote: > > > > On Thu, Jun 02, 2022 at 01:50:24PM +0800, Dongliang Mu wrote: > > > From: Dongliang Mu > > > > > > Commit d725d20e81c2 ("media: flexcop-usb: sanity checking of endpoint type > > > ") adds a sanity check for endpoint[1], but fails to modify the sanity > > > check of bNumEndpoints. > > > > > > Fix this by modifying the sanity check of bNumEndpoints to 2. > > > > Are you sure that d725d20e81c2 ("media: flexcop-usb: sanity checking of > > endpoint type) was correct? > > I am not sure if fc_usb->uintf->cur_altsetting->endpoint[1] is right or not. > > But the sanity check of bNumEndpoints does not match the following dereference. I should know better than try to be subtle on the internet: Your fix is wrong. You need to try to understand the code you're changing. Not just do pattern matching. > > > Fixes: d725d20e81c2 ("media: flexcop-usb: sanity checking of endpoint type") > > > Signed-off-by: Dongliang Mu > > > --- > > > drivers/media/usb/b2c2/flexcop-usb.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/drivers/media/usb/b2c2/flexcop-usb.c b/drivers/media/usb/b2c2/flexcop-usb.c > > > index 7835bb0f32fc..eb54bfdda01f 100644 > > > --- a/drivers/media/usb/b2c2/flexcop-usb.c > > > +++ b/drivers/media/usb/b2c2/flexcop-usb.c > > > @@ -509,7 +509,7 @@ static int flexcop_usb_init(struct flexcop_usb *fc_usb) > > > return ret; > > > } > > > > > > - if (fc_usb->uintf->cur_altsetting->desc.bNumEndpoints < 1) > > > + if (fc_usb->uintf->cur_altsetting->desc.bNumEndpoints < 2) > > > return -ENODEV; > > > if (!usb_endpoint_is_isoc_in(&fc_usb->uintf->cur_altsetting->endpoint[1].desc)) > > > return -ENODEV; > > > > It looks like it should have verified the type of endpoint[0] here > > instead. > > This sanity check originally makes sure the > fc_usb->uintf->cur_altsetting->endpoint[0] in > flexcop_usb_transfer_init. Yes, and that is the only endpoint that this driver uses. I've posted a fix here: https://lore.kernel.org/r/20220609135341.19941-1-johan@kernel.org Johan