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=-13.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 10355C43387 for ; Fri, 11 Jan 2019 14:36:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CCB362133F for ; Fri, 11 Jan 2019 14:36:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547217366; bh=ceNKCBEx/bTuRfTe5vR6gQwrWfrHc1rL0mvbIbeGsx4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=PhdRzIJoYvTrjXVGtf2ycSuCBbvLLFkB/UpM2P7QkMWiV5xIMcYniPQReIHF3MEoj 7IzlyXOZkusRHgJRaIzG1mlSErvsSaFQkMl2ai3PG/mtSP4nJNeFU7nGPxYIeUDHJQ Vuvw4Q5pyoVZJeyleSgY0w+U3ZYvFTltGtD29bNU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390293AbfAKOgF (ORCPT ); Fri, 11 Jan 2019 09:36:05 -0500 Received: from mail.kernel.org ([198.145.29.99]:56354 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390276AbfAKOgD (ORCPT ); Fri, 11 Jan 2019 09:36:03 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.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 AEA462063F; Fri, 11 Jan 2019 14:36:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547217362; bh=ceNKCBEx/bTuRfTe5vR6gQwrWfrHc1rL0mvbIbeGsx4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JFzH728khb6NSL8kVS4YD7rAVqZE3tgRR6OcapHaJBT1UYHbtH0V8KGdjZkYTWtL6 RQLztpBMEg7bW7UjGefZmCHvnTzyOTTjg3a/4O8W+2in/QO0ap7M0deiBjdaerFQG4 6YnAO44cHKfWxo5obMQzPIFYtghoFcHAhgtj7dfM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Martin Zaharinov , Florian Westphal , Pablo Neira Ayuso , Sasha Levin Subject: [PATCH 4.19 034/148] netfilter: nat: cant use dst_hold on noref dst Date: Fri, 11 Jan 2019 15:13:32 +0100 Message-Id: <20190111131115.660596561@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190111131114.337122649@linuxfoundation.org> References: <20190111131114.337122649@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit 542fbda0f08f1cbbc250f9e59f7537649651d0c8 ] The dst entry might already have a zero refcount, waiting on rcu list to be free'd. Using dst_hold() transitions its reference count to 1, and next dst release will try to free it again -- resulting in a double free: WARNING: CPU: 1 PID: 0 at include/net/dst.h:239 nf_xfrm_me_harder+0xe7/0x130 [nf_nat] RIP: 0010:nf_xfrm_me_harder+0xe7/0x130 [nf_nat] Code: 48 8b 5c 24 60 65 48 33 1c 25 28 00 00 00 75 53 48 83 c4 68 5b 5d 41 5c c3 85 c0 74 0d 8d 48 01 f0 0f b1 0a 74 86 85 c0 75 f3 <0f> 0b e9 7b ff ff ff 29 c6 31 d2 b9 20 00 48 00 4c 89 e7 e8 31 27 Call Trace: nf_nat_ipv4_out+0x78/0x90 [nf_nat_ipv4] nf_hook_slow+0x36/0xd0 ip_output+0x9f/0xd0 ip_forward+0x328/0x440 ip_rcv+0x8a/0xb0 Use dst_hold_safe instead and bail out if we cannot take a reference. Fixes: a4c2fd7f7891 ("net: remove DST_NOCACHE flag") Reported-by: Martin Zaharinov Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin --- net/netfilter/nf_nat_core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c index e2b196054dfc..2268b10a9dcf 100644 --- a/net/netfilter/nf_nat_core.c +++ b/net/netfilter/nf_nat_core.c @@ -117,7 +117,8 @@ int nf_xfrm_me_harder(struct net *net, struct sk_buff *skb, unsigned int family) dst = skb_dst(skb); if (dst->xfrm) dst = ((struct xfrm_dst *)dst)->route; - dst_hold(dst); + if (!dst_hold_safe(dst)) + return -EHOSTUNREACH; if (sk && !net_eq(net, sock_net(sk))) sk = NULL; -- 2.19.1