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 BBA4FC433EF for ; Fri, 3 Jun 2022 18:14:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346411AbiFCSOe (ORCPT ); Fri, 3 Jun 2022 14:14:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48530 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346374AbiFCSAP (ORCPT ); Fri, 3 Jun 2022 14:00:15 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E2E0B583BA; Fri, 3 Jun 2022 10:56:19 -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 5C73C6147E; Fri, 3 Jun 2022 17:56:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6DB71C385A9; Fri, 3 Jun 2022 17:56:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1654278978; bh=+jKGu2m+qotB5j1a1TjLLakeDpMh01+5nUzTVxMt6Vo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yRuprK4N0uW9KA91MoS6frGxWtvLNGq9+Q/mYRIDBWxLZa6GOlErNDtFuCsiKffKJ pGPouzKVL4rRnlcNRzJ/6vPFDW/7FP8K1GxNETEo4wG3dYvd5rb2P5V1Emj7rpRBtx 2Verpy9UzV4VccgoS66b/61G+LxJcGvs3Cpw34r0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+793a590957d9c1b96620@syzkaller.appspotmail.com, Florian Westphal , Pablo Neira Ayuso Subject: [PATCH 5.18 14/67] netfilter: conntrack: re-fetch conntrack after insertion Date: Fri, 3 Jun 2022 19:43:15 +0200 Message-Id: <20220603173821.142120889@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220603173820.731531504@linuxfoundation.org> References: <20220603173820.731531504@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Florian Westphal commit 56b14ecec97f39118bf85c9ac2438c5a949509ed upstream. In case the conntrack is clashing, insertion can free skb->_nfct and set skb->_nfct to the already-confirmed entry. This wasn't found before because the conntrack entry and the extension space used to free'd after an rcu grace period, plus the race needs events enabled to trigger. Reported-by: Fixes: 71d8c47fc653 ("netfilter: conntrack: introduce clash resolution on insertion race") Fixes: 2ad9d7747c10 ("netfilter: conntrack: free extension area immediately") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman --- include/net/netfilter/nf_conntrack_core.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/include/net/netfilter/nf_conntrack_core.h +++ b/include/net/netfilter/nf_conntrack_core.h @@ -58,8 +58,13 @@ static inline int nf_conntrack_confirm(s int ret = NF_ACCEPT; if (ct) { - if (!nf_ct_is_confirmed(ct)) + if (!nf_ct_is_confirmed(ct)) { ret = __nf_conntrack_confirm(skb); + + if (ret == NF_ACCEPT) + ct = (struct nf_conn *)skb_nfct(skb); + } + if (likely(ret == NF_ACCEPT)) nf_ct_deliver_cached_events(ct); }