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 22C35C4167B for ; Fri, 9 Dec 2022 08:46:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229818AbiLIIqS (ORCPT ); Fri, 9 Dec 2022 03:46:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50708 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229836AbiLIIqQ (ORCPT ); Fri, 9 Dec 2022 03:46:16 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7B19C60B66; Fri, 9 Dec 2022 00:46:14 -0800 (PST) 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 dfw.source.kernel.org (Postfix) with ESMTPS id E22E5621AF; Fri, 9 Dec 2022 08:46:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C6C8AC433D2; Fri, 9 Dec 2022 08:46:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1670575573; bh=kiDuII4PVIIcqLJKDcSXlROJbKzIK1z1ZcNVnhqJlzU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=q1OSGugcberDs7RYPfUWvgRDoYld0nsAenFteVxu0VpRNhLjKm23Ry3XhMAnQLxIo cu4+WqdfZDkkpSVZs45r6yRkXmt+KC6G1c/8s0PMCUbxARduz3uPncqVcz4FL2XHL5 r3d7ZjVu8jKTyi4wvdto27Gz8myuxEkI736ngsSo= Date: Fri, 9 Dec 2022 09:46:09 +0100 From: Greg KH To: "Guozihua (Scott)" Cc: Mimi Zohar , dmitry.kasatkin@gmail.com, Paul Moore , sds@tycho.nsa.gov, eparis@parisplace.org, sashal@kernel.org, selinux@vger.kernel.org, "linux-integrity@vger.kernel.org" , stable@vger.kernel.org Subject: Re: [RFC] IMA LSM based rule race condition issue on 4.19 LTS Message-ID: References: <389334fe-6e12-96b2-6ce9-9f0e8fcb85bf@huawei.com> <93d137dc-e0d3-3741-7e01-dca1ba9c0903@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <93d137dc-e0d3-3741-7e01-dca1ba9c0903@huawei.com> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Fri, Dec 09, 2022 at 03:53:25PM +0800, Guozihua (Scott) wrote: > On 2022/12/9 15:12, Greg KH wrote: > > On Fri, Dec 09, 2022 at 03:00:35PM +0800, Guozihua (Scott) wrote: > > > Hi community. > > > > > > Previously our team reported a race condition in IMA relates to LSM based > > > rules which would case IMA to match files that should be filtered out under > > > normal condition. The issue was originally analyzed and fixed on mainstream. > > > The patch and the discussion could be found here: > > > https://lore.kernel.org/all/20220921125804.59490-1-guozihua@huawei.com/ > > > > > > After that, we did a regression test on 4.19 LTS and the same issue arises. > > > Further analysis reveled that the issue is from a completely different > > > cause. > > > > What commit in the tree fixed this in newer kernels? Why can't we just > > backport that one to 4.19.y as well? > > > > thanks, > > > > greg k-h > > Hi Greg, > > The fix for mainline is now on linux-next, commit d57378d3aa4d ("ima: > Simplify ima_lsm_copy_rule") and c7423dbdbc9ece ("ima: Handle -ESTALE > returned by ima_filter_rule_match()"). However, these patches cannot be > picked directly into 4.19.y due to code difference. Ok, so it's much more than just 4.19 that's an issue here. And are those commits tagged for stable inclusion? > The commit which introduced the issue on mainline was believed to be > b16942455193 ("ima: use the lsm policy update notifier"), which is not in > 4.19.y. And the mainline patch is designed to handle the situation when IMA > rules are accessed through RCU which has not been implemented on 4.19.y > either. Ok, then provide a series of backports to 4.19 and we will be glad to review them. thanks, greg k-h