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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 C31DEC10F29 for ; Tue, 17 Mar 2020 11:16:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8B8B4205ED for ; Tue, 17 Mar 2020 11:16:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584443769; bh=XAYkwsLZI0Sg17MYyeRz/0WyS2H9AG2/pvpvFulgFAs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=WTQREwPKXwUy5i6svpy7WSriVu2NcvYqM2+r7e3aoa7DWqUqA647SsKbpUHFOO8sw 1+nzdy7QE0n4OLCyQWtdYkzUIwOfVF7ZgpxvwaUN0K2WnZjVpglBz5JHzHnKoluLER ZCiFH48GWzpjD5Oc5t/UKKnl7BtRIV3bbUlbnHhs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729070AbgCQLKO (ORCPT ); Tue, 17 Mar 2020 07:10:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:52986 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728732AbgCQLKO (ORCPT ); Tue, 17 Mar 2020 07:10:14 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 71C6120658; Tue, 17 Mar 2020 11:10:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584443413; bh=XAYkwsLZI0Sg17MYyeRz/0WyS2H9AG2/pvpvFulgFAs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pbkeH2WEpcOMvSvOwT4wUNpXHJq/ZLzIbuGWODdbi6rd3pH1zds+cK/SzTOM2Gi+Z L7XMIb6U88NF5pHcDDHv9Of+J1grXh+aT4ogFe7xh5TRplNQiS7v9HlvutNNtEV/Jc UQsd2nYmm8lU37yBJok4qSqpc5L4Q10wCffhwua0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Florian Westphal , Pablo Neira Ayuso Subject: [PATCH 5.5 075/151] netfilter: nf_tables: fix infinite loop when expr is not available Date: Tue, 17 Mar 2020 11:54:45 +0100 Message-Id: <20200317103331.815854847@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200317103326.593639086@linuxfoundation.org> References: <20200317103326.593639086@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Florian Westphal commit 1d305ba40eb8081ff21eeb8ca6ba5c70fd920934 upstream. nft will loop forever if the kernel doesn't support an expression: 1. nft_expr_type_get() appends the family specific name to the module list. 2. -EAGAIN is returned to nfnetlink, nfnetlink calls abort path. 3. abort path sets ->done to true and calls request_module for the expression. 4. nfnetlink replays the batch, we end up in nft_expr_type_get() again. 5. nft_expr_type_get attempts to append family-specific name. This one already exists on the list, so we continue 6. nft_expr_type_get adds the generic expression name to the module list. -EAGAIN is returned, nfnetlink calls abort path. 7. abort path encounters the family-specific expression which has 'done' set, so it gets removed. 8. abort path requests the generic expression name, sets done to true. 9. batch is replayed. If the expression could not be loaded, then we will end up back at 1), because the family-specific name got removed and the cycle starts again. Note that userspace can SIGKILL the nft process to stop the cycle, but the desired behaviour is to return an error after the generic expr name fails to load the expression. Fixes: eb014de4fd418 ("netfilter: nf_tables: autoload modules from the abort path") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman --- net/netfilter/nf_tables_api.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -7250,13 +7250,8 @@ static void nf_tables_module_autoload(st list_splice_init(&net->nft.module_list, &module_list); mutex_unlock(&net->nft.commit_mutex); list_for_each_entry_safe(req, next, &module_list, list) { - if (req->done) { - list_del(&req->list); - kfree(req); - } else { - request_module("%s", req->module); - req->done = true; - } + request_module("%s", req->module); + req->done = true; } mutex_lock(&net->nft.commit_mutex); list_splice(&module_list, &net->nft.module_list); @@ -8039,6 +8034,7 @@ static void __net_exit nf_tables_exit_ne __nft_release_tables(net); mutex_unlock(&net->nft.commit_mutex); WARN_ON_ONCE(!list_empty(&net->nft.tables)); + WARN_ON_ONCE(!list_empty(&net->nft.module_list)); } static struct pernet_operations nf_tables_net_ops = {