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=-3.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 C37F0C31E45 for ; Thu, 13 Jun 2019 15:50:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A4B1820851 for ; Thu, 13 Jun 2019 15:50:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388245AbfFMPun (ORCPT ); Thu, 13 Jun 2019 11:50:43 -0400 Received: from mx2.suse.de ([195.135.220.15]:55976 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1731686AbfFMJN4 (ORCPT ); Thu, 13 Jun 2019 05:13:56 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 84498AEFC; Thu, 13 Jun 2019 09:13:55 +0000 (UTC) Date: Thu, 13 Jun 2019 11:13:55 +0200 Message-ID: From: Takashi Iwai To: Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, syzbot+e4c8abb920efa77bace9@syzkaller.appspotmail.com, Sasha Levin Subject: Re: [PATCH 4.14 61/81] ALSA: seq: Protect in-kernel ioctl calls with mutex In-Reply-To: <20190613091122.GA31122@kroah.com> References: <20190613075649.074682929@linuxfoundation.org> <20190613075653.581995283@linuxfoundation.org> <20190613091122.GA31122@kroah.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.3 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Takashi