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 55765C7EE2A for ; Mon, 22 May 2023 19:38:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235042AbjEVTiN (ORCPT ); Mon, 22 May 2023 15:38:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59556 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234979AbjEVTiA (ORCPT ); Mon, 22 May 2023 15:38:00 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2F1B61AC for ; Mon, 22 May 2023 12:37:48 -0700 (PDT) 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 BB2E5629AD for ; Mon, 22 May 2023 19:37:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3C19C4339B; Mon, 22 May 2023 19:37:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1684784241; bh=PmKOtY4oW99JfCuMcNgepbj8czKpOfIkEmc2W+A7T4U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yEo3fMCtwbGa2cjOZaE0az0xHc06P+GzJI4+a698WQ46YFVKIbb/M8KQuB/cwtnLy e4pQtFWBQEZp5Bf/glpzo1gLue0/h/Q0UdyuDF8p4tUcJSdWLE8zBnkOJ2YeHKEeJz m7EEKC4h0n2GKsWRNWNAg1bWOaVaLWibzh5RM+lM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Florian Westphal , Pablo Neira Ayuso , Sasha Levin Subject: [PATCH 6.3 017/364] netfilter: conntrack: fix possible bug_on with enable_hooks=1 Date: Mon, 22 May 2023 20:05:22 +0100 Message-Id: <20230522190413.257542943@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230522190412.801391872@linuxfoundation.org> References: <20230522190412.801391872@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Florian Westphal [ Upstream commit e72eeab542dbf4f544e389e64fa13b82a1b6d003 ] I received a bug report (no reproducer so far) where we trip over 712 rcu_read_lock(); 713 ct_hook = rcu_dereference(nf_ct_hook); 714 BUG_ON(ct_hook == NULL); // here In nf_conntrack_destroy(). First turn this BUG_ON into a WARN. I think it was triggered via enable_hooks=1 flag. When this flag is turned on, the conntrack hooks are registered before nf_ct_hook pointer gets assigned. This opens a short window where packets enter the conntrack machinery, can have skb->_nfct set up and a subsequent kfree_skb might occur before nf_ct_hook is set. Call nf_conntrack_init_end() to set nf_ct_hook before we register the pernet ops. Fixes: ba3fbe663635 ("netfilter: nf_conntrack: provide modparam to always register conntrack hooks") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin --- net/netfilter/core.c | 6 ++++-- net/netfilter/nf_conntrack_standalone.c | 3 ++- 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/net/netfilter/core.c b/net/netfilter/core.c index 358220b585215..edf92074221e2 100644 --- a/net/netfilter/core.c +++ b/net/netfilter/core.c @@ -699,9 +699,11 @@ void nf_conntrack_destroy(struct nf_conntrack *nfct) rcu_read_lock(); ct_hook = rcu_dereference(nf_ct_hook); - BUG_ON(ct_hook == NULL); - ct_hook->destroy(nfct); + if (ct_hook) + ct_hook->destroy(nfct); rcu_read_unlock(); + + WARN_ON(!ct_hook); } EXPORT_SYMBOL(nf_conntrack_destroy); diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c index 57f6724c99a76..169e16fc2bceb 100644 --- a/net/netfilter/nf_conntrack_standalone.c +++ b/net/netfilter/nf_conntrack_standalone.c @@ -1218,11 +1218,12 @@ static int __init nf_conntrack_standalone_init(void) nf_conntrack_htable_size_user = nf_conntrack_htable_size; #endif + nf_conntrack_init_end(); + ret = register_pernet_subsys(&nf_conntrack_net_ops); if (ret < 0) goto out_pernet; - nf_conntrack_init_end(); return 0; out_pernet: -- 2.39.2