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=-6.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no 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 CA6D3C433DB for ; Sat, 6 Feb 2021 22:30:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8582864E88 for ; Sat, 6 Feb 2021 22:30:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229562AbhBFWaH (ORCPT ); Sat, 6 Feb 2021 17:30:07 -0500 Received: from mail.kernel.org ([198.145.29.99]:46898 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229522AbhBFWaG (ORCPT ); Sat, 6 Feb 2021 17:30:06 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id DAB9C64DA1; Sat, 6 Feb 2021 22:29:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1612650565; bh=5whCFGTXa3J1746EODCwZovMzZz+QDWnX+nqhWJoo8Q=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=KVbBniO58u4QFUB32f9KRwF91AQ+EOH3Kx8zSld2dTKeS6bbVngC8lN72bAzfjChU YUyZhRLKOKOXDO5gxQCDAz3mX29oH29sevZ8Uq7CBif+qhiyCNbQFVq2+7gS0lWpII 4OOIAnMrjzqqky0uF+yK1je0plwSI4cGz8QhkwRWJEnaulhQHOWyLAJE1L3uaSdWzt pMjZse5mPqyzYrP+8JcAYBI/6qGeasmvWuDb5Qg4t3+daMlPMNbG/ULsmZwMHMmmBv WoQRsmkyFf/9YN+81bLJKOeuDc7LqZ8GvFworFp2kV9jIXY7gtX9/lNMetjRU+CLPe bWI29EbUd4ilg== Date: Sat, 6 Feb 2021 14:29:24 -0800 From: Jakub Kicinski To: Andrew Morton Cc: NeilBrown , Alexander Viro , Jonathan Corbet , Xin Long , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, Ingo Molnar , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Vlad Yasevich , Neil Horman , Marcelo Ricardo Leitner , "David S. Miller" , linux-sctp@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH 0/3] Fix some seq_file users that were recently broken Message-ID: <20210206142924.2bfc3cf5@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: <20210205143550.58d3530918459eafa918ad0c@linux-foundation.org> References: <161248518659.21478.2484341937387294998.stgit@noble1> <20210205143550.58d3530918459eafa918ad0c@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-sctp@vger.kernel.org On Fri, 5 Feb 2021 14:35:50 -0800 Andrew Morton wrote: > On Fri, 05 Feb 2021 11:36:30 +1100 NeilBrown wrote: > > > A recent change to seq_file broke some users which were using seq_file > > in a non-"standard" way ... though the "standard" isn't documented, so > > they can be excused. The result is a possible leak - of memory in one > > case, of references to a 'transport' in the other. > > > > These three patches: > > 1/ document and explain the problem > > 2/ fix the problem user in x86 > > 3/ fix the problem user in net/sctp > > 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and > interface") was August 2018, so I don't think "recent" applies here? > > I didn't look closely, but it appears that the sctp procfs file is > world-readable. So we gave unprivileged userspace the ability to leak > kernel memory? > > So I'm thinking that we aim for 5.12-rc1 on all three patches with a cc:stable? I'd rather take the sctp patch sooner, we'll send another batch of networking fixes for 5.11, anyway. Would that be okay with you?