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=-14.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=ham 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 6CDF5C4338F for ; Thu, 29 Jul 2021 12:46:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 53EEF60EBC for ; Thu, 29 Jul 2021 12:46:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237056AbhG2MqU (ORCPT ); Thu, 29 Jul 2021 08:46:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35878 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237203AbhG2MqS (ORCPT ); Thu, 29 Jul 2021 08:46:18 -0400 Received: from mail-lj1-x22f.google.com (mail-lj1-x22f.google.com [IPv6:2a00:1450:4864:20::22f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4BF6DC0613D3; Thu, 29 Jul 2021 05:46:14 -0700 (PDT) Received: by mail-lj1-x22f.google.com with SMTP id e5so7393771ljp.6; Thu, 29 Jul 2021 05:46:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=aOPMjYxSfcLxQO5DXf2cS5DmYr4eh4QbyClofMVpXyI=; b=XkvrSAPqzJi48W/X2lSLbgNnRGe8o+NyrHsiPiJmsHlrRDqEo+cdPj+rz0MrAGhGHg HGzNB36puxEs4gcm8P2OgFjqET6Dnh83N+BWbBOKhNTmBXYXZ2p3Lngm6TUnUsW8ZYnx 5GUIu6gBncw4hEKlLN1kq+flJmLKVkALxejlGTn824E74q4GyInamllYGPvcifmfw2xv PNUziFALxnNMxABcU/Zzc20YSQQMRV3Tglgko/5uSSrZ/CF6cI+K7L8GdGEhsamXWEl5 zQsTuRPwAR2OCyr/2xrpXoWXStoE/4u9U2Vgc0EBLO1r9gS2j+7HRtPGg1J3e8MFjHm5 RYNw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=aOPMjYxSfcLxQO5DXf2cS5DmYr4eh4QbyClofMVpXyI=; b=CXrhoKIiYCPivu4Qs/h+8L5uhBLWDet7a8TkoV7MTzdQN1dZDXgOjo7fKuaratfdM7 sPJCu5jShgMQm7Q5CjRziul8H9TfMGrZucMOnnnbrNTVY4U00hxo8xJ4///fdGVA0szL HDZuKQi/3x+nmR4qLJroTphBMY530Owk1QpEDjsyMSpF3HHmMiHWa/jnMO3HPGxWOyjE /hajak/F/fYgmf+LE2vk50eZu7IMek0CGotQkeb/M2xzmmErSVYMedZVmv2EWo77M6Ta tBSpURx8EpaTPPCx7ChALjHCOV+P2UrhTJm7TqwnkNCGfvPulqyNq/g3HL/iJ5uiI0Av +KOg== X-Gm-Message-State: AOAM5324dE0N95NZ7NJFxrH11DTpr/yk9N1ISS/9eWqraMIURtQV7ung 7aMgAPv6ULN/0wSXLprRE2s= X-Google-Smtp-Source: ABdhPJwKZygKILp6tWJIGvxjQHtv30yI9MQglDPErSO/+wyW06OS+yj8lxy6IJrs4N2UOVXBGm43tw== X-Received: by 2002:a05:651c:1587:: with SMTP id h7mr2795884ljq.110.1627562772640; Thu, 29 Jul 2021 05:46:12 -0700 (PDT) Received: from localhost.localdomain ([94.103.227.213]) by smtp.gmail.com with ESMTPSA id g28sm295555lfj.279.2021.07.29.05.46.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 29 Jul 2021 05:46:12 -0700 (PDT) Date: Thu, 29 Jul 2021 15:45:56 +0300 From: Pavel Skripkin To: Hans Verkuil Cc: mchehab@kernel.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, syzbot+a6969ef522a36d3344c9@syzkaller.appspotmail.com Subject: Re: [PATCH v2] media: em28xx: add missing em28xx_close_extension Message-ID: <20210729154556.6e257405@gmail.com> In-Reply-To: <3b1de658-ebf0-e45f-49ef-953e3467e7d4@xs4all.nl> References: <7df1705e-b2c7-ddfc-9cc5-582fb1a304e5@xs4all.nl> <20210721194307.12155-1-paskripkin@gmail.com> <3b1de658-ebf0-e45f-49ef-953e3467e7d4@xs4all.nl> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-suse-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On Thu, 29 Jul 2021 11:45:19 +0200 Hans Verkuil wrote: > On 21/07/2021 21:43, Pavel Skripkin wrote: > > If em28xx dev has ->dev_next pointer, we need to delete dev_next > > list node from em28xx_extension_devlist on disconnect to avoid UAF > > bugs and corrupted list bugs, since driver frees this pointer on > > disconnect. > > > > Fixes: 1a23f81b7dc3 ("V4L/DVB (9979): em28xx: move usb probe code > > to a proper place") Reported-and-tested-by: > > syzbot+a6969ef522a36d3344c9@syzkaller.appspotmail.com > > Signed-off-by: Pavel Skripkin --- > > > > Changes in v2: > > Previous patch was completely broken. I've done some > > debugging again and found true root case of the reported bug. > > > > --- > > drivers/media/usb/em28xx/em28xx-cards.c | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/media/usb/em28xx/em28xx-cards.c > > b/drivers/media/usb/em28xx/em28xx-cards.c index > > c1e0dccb7408..d56b040e1bd7 100644 --- > > a/drivers/media/usb/em28xx/em28xx-cards.c +++ > > b/drivers/media/usb/em28xx/em28xx-cards.c @@ -4139,8 +4139,10 @@ > > static void em28xx_usb_disconnect(struct usb_interface *intf) > > em28xx_close_extension(dev); > > > > - if (dev->dev_next) > > + if (dev->dev_next) { > > em28xx_release_resources(dev->dev_next); > > + em28xx_close_extension(dev->dev_next); > > Wouldn't it be better to swap these two? > > That order is also used for em28xx_close_extension(dev) and > em28xx_release_resources(dev). > > You do need to store dev->dev_next in a temp variable, though. > Hi, Hans! I don't understand why I need to store dev->dev_next in a temp variable. I don't see code in em28xx_release_resources() or em28xx_close_extension() that zeroes this pointer. With regards, Pavel Skripkin