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=-5.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 39514C31E45 for ; Thu, 13 Jun 2019 16:28:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 111FF2175B for ; Thu, 13 Jun 2019 16:28:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560443290; bh=pTWfd28rxTsC36j5nVi4lXHdrxsHMLFah47TRp8/Hl0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=eaYHJLwzZjVXe/J8qBEJwHr8s6rp/iMLAymyFQQRTqSXTHEy8Rbsj1gb5ieYpLNrv oNF96YKYkuIyfcS8MTzFZmHxjqAdJ3PYOoSZNIS0Twqz3/oLLxLkgakO4+2doKv1XX NsLfXYsBsWIwo+NJwZybmd6KEXJkE+EDEfIlqUZM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403893AbfFMQ2I (ORCPT ); Thu, 13 Jun 2019 12:28:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:48964 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727271AbfFMQ2G (ORCPT ); Thu, 13 Jun 2019 12:28:06 -0400 Received: from localhost (unknown [131.107.160.220]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9EE1F21743; Thu, 13 Jun 2019 16:28:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560443285; bh=pTWfd28rxTsC36j5nVi4lXHdrxsHMLFah47TRp8/Hl0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jH+hYGmLO1NFzZnYcUN5UZLEqmsoQQ3AoV3p5xisj858SDLvyW9Nh3RakQJBRYq4g oBxFnQEyHGkFv/4dw+UJxCsMrHHu5+M315FphN83xvW4/NOf+v9mP2WcwFdyfr8Zdk pJD1fokgt1FQHAtnRbEeOUG/eM3pCje3IPwso66A= Date: Thu, 13 Jun 2019 12:28:05 -0400 From: Sasha Levin To: Takashi Iwai Cc: Greg Kroah-Hartman , linux-kernel@vger.kernel.org, stable@vger.kernel.org, syzbot+e4c8abb920efa77bace9@syzkaller.appspotmail.com Subject: Re: [PATCH 4.14 61/81] ALSA: seq: Protect in-kernel ioctl calls with mutex Message-ID: <20190613162805.GI1513@sasha-vm> References: <20190613075649.074682929@linuxfoundation.org> <20190613075653.581995283@linuxfoundation.org> <20190613091122.GA31122@kroah.com> <20190613153946.GG1513@sasha-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 13, 2019 at 05:44:15PM +0200, Takashi Iwai wrote: >On Thu, 13 Jun 2019 17:39:46 +0200, >Sasha Levin wrote: >> >> On Thu, Jun 13, 2019 at 11:13:55AM +0200, Takashi Iwai wrote: >> >On Thu, 13 Jun 2019 11:11:22 +0200, >> >Greg Kroah-Hartman wrote: >> >> >> >> On Thu, Jun 13, 2019 at 11:02:54AM +0200, Takashi Iwai wrote: >> >> > On Thu, 13 Jun 2019 10:33:44 +0200, >> >> > Greg Kroah-Hartman wrote: >> >> > > >> >> > > [ Upstream commit feb689025fbb6f0aa6297d3ddf97de945ea4ad32 ] >> >> > > >> >> > > ALSA OSS sequencer calls the ioctl function indirectly via >> >> > > snd_seq_kernel_client_ctl(). While we already applied the protection >> >> > > against races between the normal ioctls and writes via the client's >> >> > > ioctl_mutex, this code path was left untouched. And this seems to be >> >> > > the cause of still remaining some rare UAF as spontaneously triggered >> >> > > by syzkaller. >> >> > > >> >> > > For the sake of robustness, wrap the ioctl_mutex also for the call via >> >> > > snd_seq_kernel_client_ctl(), too. >> >> > > >> >> > > Reported-by: syzbot+e4c8abb920efa77bace9@syzkaller.appspotmail.com >> >> > > Signed-off-by: Takashi Iwai >> >> > > Signed-off-by: Sasha Levin >> >> > >> >> > This commit is reverted later by commit f0654ba94e33. >> >> > So please drop this. The proper fix is done later by commit >> >> > 7c32ae35fbf9 ("ALSA: seq: Cover unsubscribe_port() in list_mutex") >> >> > >> >> > Ditto for 4.19.y and 5.1.y. >> >> >> >> Now dropped everywhere, and I added 7c32ae35fbf9 ("ALSA: seq: Cover >> >> unsubscribe_port() in list_mutex") everywhere instead. >> > >> >Thanks! >> > >> >BTW, do we have a systematic check whether the selected stable commit >> >is reverted in a later commit? At least, you can track it as long as >> >Fixes tag is properly set. >> >> I have that scripting in place, and I usually check it once before I >> send the initial reviews and then once Greg does the -rc release. > >OK, good to hear. So this time must be some exceptional error. I still run these manually (I guess it's time to automate that too), so it happens sometimes that folks notice these faster :) -- Thanks, Sasha