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=-14.8 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, MENTIONS_GIT_HOSTING,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 8C466C4320E for ; Mon, 30 Aug 2021 04:41:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7117A60F5C for ; Mon, 30 Aug 2021 04:41:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229994AbhH3Emt (ORCPT ); Mon, 30 Aug 2021 00:42:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54978 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229379AbhH3Emp (ORCPT ); Mon, 30 Aug 2021 00:42:45 -0400 Received: from mail-pf1-x430.google.com (mail-pf1-x430.google.com [IPv6:2607:f8b0:4864:20::430]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F2EE9C061575; Sun, 29 Aug 2021 21:41:52 -0700 (PDT) Received: by mail-pf1-x430.google.com with SMTP id e16so10776124pfc.6; Sun, 29 Aug 2021 21:41:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=A0AD3vlBPpEOpsR6KopVre1/3DU/FQSCm9g8XHSm9pM=; b=SEC3W8w51R7HXYNhGoJV0wyZI7cT0AMXOmvlQjIEEzjellY3BMlc06aDL6F9kF/wYw U8t7KqIZDX+25MrXT4GyeiSSRcpv5RmDCKyi9cC7eKAoIkBq8eR8tUqbfg/qg8c6GnVC ju49OJ7owXAjydaLyqOfhWWmU1tXwCF/K4Aw+bCB7LlhxKLKRQXPdCqzu5d0OXwbtlre RA/4+9GA4zFDPZJnXBowkEta2uErpg85R+LjoFg6JdQRvNjs/DXGkbzaxN7TpVdxv3TU GOGlQyRjf/3V2ADf5DFl8JuPLurK4VwI6G9pyZEWSQds/aP1XeJH3F/aA2Gixg9+6Aco Uv9Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=A0AD3vlBPpEOpsR6KopVre1/3DU/FQSCm9g8XHSm9pM=; b=OZNw6kpZhXzGULlLbeqz9t61I0sKrcnllyQArKQ7M7sgt3hWiJYN+6id24ZvuphnsI CQklNvd2hsEgZhlyTrHrPEnEE41FvQ0DXN3y58h2Hoq1pEtx1fbDPCGpUotxs/wGZkKg 1rh7XVcxx57Jt3H16IppwabRqaH9eCZ73hTdHMfTapNBALdesaGPA/GVKQcJRKQcNQRX 1ex5TY9NjjhOZjq3p5TreagR9sY9Qz4n0ZEh1KZDMq1j+x+hhHqT9MvTt3KWb8nLaEfv Bj9orPES0b1ah2BmXHa6ZS3ELOAm8a6NA2UHG7lvtA/PL5IcKD+AwYWGFcYY4IvHnDA8 jq8w== X-Gm-Message-State: AOAM531v5HL13cDV7/ebMv+zq3HmupYvfEyTvGiL+5TEwWadV2jY3fvd sFuwpuXIegZEkITCfUy4Ko8= X-Google-Smtp-Source: ABdhPJzsss+ZNLzo0BIrDPgPN1zKd1lN8MuEmUxNDhCYvQtMeWLfItt0xJzDgtpbFXNc0zzfD5CNdA== X-Received: by 2002:a63:fd51:: with SMTP id m17mr19868433pgj.395.1630298512426; Sun, 29 Aug 2021 21:41:52 -0700 (PDT) Received: from [192.168.1.237] ([118.200.190.93]) by smtp.gmail.com with ESMTPSA id c23sm15387525pgb.74.2021.08.29.21.41.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 29 Aug 2021 21:41:51 -0700 (PDT) Subject: Re: [syzbot] KASAN: use-after-free Write in sco_sock_timeout To: Hillf Danton Cc: syzbot , linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org, luiz.von.dentz@intel.com, syzkaller-bugs@googlegroups.com References: <000000000000b2725705ca78de29@google.com> <20210827011931.2323-1-hdanton@sina.com> <20210829082929.2897-1-hdanton@sina.com> <11a30bc1-574f-aa1a-21d6-b886de9fc981@gmail.com> <20210830001538.1980-1-hdanton@sina.com> From: Desmond Cheong Zhi Xi Message-ID: <33d6d22f-7666-bc08-f626-3821cac9f174@gmail.com> Date: Mon, 30 Aug 2021 12:41:48 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210830001538.1980-1-hdanton@sina.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 30/8/21 8:15 am, Hillf Danton wrote: > On Mon, 30 Aug 2021 02:34:11 +0800 Desmond Cheong Zhi Xi wrote: >> >> Ok I went back to make a more thorough audit. Even without calling >> cancel_delayed_work_sync, sco_sock_timeout should not cause a UAF. >> >> I believe the real issue is that we can allocate a connection twice in >> sco_connect. This means that the first connection gets lost and we're >> unable to clean it up properly. >> >> Thoughts on this? > > LGTM regardless of the uaf reported. > > Hillf Thanks for taking a look. It passed the Syzbot reproducer too, so I think the root cause should have been addressed. I'll write up a patch to summarize what we found out. May I include you as a Co-developed-by: author? >> >> #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git e3f30ab28ac8 >> >> --- a/net/bluetooth/sco.c >> +++ b/net/bluetooth/sco.c >> @@ -578,9 +578,6 @@ static int sco_sock_connect(struct socket *sock, struct sockaddr *addr, int alen >> addr->sa_family != AF_BLUETOOTH) >> return -EINVAL; >> >> - if (sk->sk_state != BT_OPEN && sk->sk_state != BT_BOUND) >> - return -EBADFD; >> - >> if (sk->sk_type != SOCK_SEQPACKET) >> return -EINVAL; >> >> @@ -591,6 +588,13 @@ static int sco_sock_connect(struct socket *sock, struct sockaddr *addr, int alen >> >> lock_sock(sk); >> >> + if (sk->sk_state != BT_OPEN && sk->sk_state != BT_BOUND) { >> + hci_dev_unlock(hdev); >> + hci_dev_put(hdev); >> + err = -EBADFD; >> + goto done; >> + } >> + >> /* Set destination address and psm */ >> bacpy(&sco_pi(sk)->dst, &sa->sco_bdaddr); >> >>