From patchwork Mon Jan 28 08:35:35 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin Willi X-Patchwork-Id: 1031746 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=strongswan.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 43p38n5DfKz9s7h for ; Mon, 28 Jan 2019 19:44:41 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726754AbfA1Iok (ORCPT ); Mon, 28 Jan 2019 03:44:40 -0500 Received: from sitav-80046.hsr.ch ([152.96.80.46]:53766 "EHLO mail.strongswan.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726668AbfA1Iok (ORCPT ); Mon, 28 Jan 2019 03:44:40 -0500 X-Greylist: delayed 533 seconds by postgrey-1.27 at vger.kernel.org; Mon, 28 Jan 2019 03:44:39 EST Received: from book.wlp.is (unknown [185.12.128.225]) by mail.strongswan.org (Postfix) with ESMTPSA id 46B084056B; Mon, 28 Jan 2019 09:35:47 +0100 (CET) From: Martin Willi To: Steffen Klassert Cc: netdev@vger.kernel.org Subject: [PATCH] esp: Skip TX bytes accounting when sending from a request socket Date: Mon, 28 Jan 2019 09:35:35 +0100 Message-Id: <20190128083535.18006-1-martin@strongswan.org> X-Mailer: git-send-email 2.17.1 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On ESP output, sk_wmem_alloc is incremented for the added padding if a socket is associated to the skb. When replying with TCP SYNACKs over IPsec, the associated sk is a casted request socket, only. Increasing sk_wmem_alloc on a request socket results in a write at an arbitrary struct offset. In the best case, this produces the following WARNING: WARNING: CPU: 1 PID: 0 at lib/refcount.c:102 esp_output_head+0x2e4/0x308 [esp4] refcount_t: addition on 0; use-after-free. CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.0.0-rc3 #2 Hardware name: Marvell Armada 380/385 (Device Tree) [...] [] (esp_output_head [esp4]) from [] (esp_output+0xb8/0x180 [esp4]) [] (esp_output [esp4]) from [] (xfrm_output_resume+0x558/0x664) [] (xfrm_output_resume) from [] (xfrm4_output+0x44/0xc4) [] (xfrm4_output) from [] (tcp_v4_send_synack+0xa8/0xe8) [] (tcp_v4_send_synack) from [] (tcp_conn_request+0x7f4/0x948) [] (tcp_conn_request) from [] (tcp_rcv_state_process+0x2a0/0xe64) [] (tcp_rcv_state_process) from [] (tcp_v4_do_rcv+0xf0/0x1f4) [] (tcp_v4_do_rcv) from [] (tcp_v4_rcv+0xdb8/0xe20) [] (tcp_v4_rcv) from [] (ip_protocol_deliver_rcu+0x2c/0x2dc) [] (ip_protocol_deliver_rcu) from [] (ip_local_deliver_finish+0x48/0x54) [] (ip_local_deliver_finish) from [] (ip_local_deliver+0x54/0xec) [] (ip_local_deliver) from [] (ip_rcv+0x48/0xb8) [] (ip_rcv) from [] (__netif_receive_skb_one_core+0x50/0x6c) [...] The issue triggers only when not using TCP syncookies, as for syncookies no socket is associated. Fixes: cac2661c53f3 ("esp4: Avoid skb_cow_data whenever possible") Fixes: 03e2a30f6a27 ("esp6: Avoid skb_cow_data whenever possible") Signed-off-by: Martin Willi --- net/ipv4/esp4.c | 2 +- net/ipv6/esp6.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c index 5459f41fc26f..10e809b296ec 100644 --- a/net/ipv4/esp4.c +++ b/net/ipv4/esp4.c @@ -328,7 +328,7 @@ int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info * skb->len += tailen; skb->data_len += tailen; skb->truesize += tailen; - if (sk) + if (sk && sk_fullsock(sk)) refcount_add(tailen, &sk->sk_wmem_alloc); goto out; diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c index 5afe9f83374d..239d4a65ad6e 100644 --- a/net/ipv6/esp6.c +++ b/net/ipv6/esp6.c @@ -296,7 +296,7 @@ int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info skb->len += tailen; skb->data_len += tailen; skb->truesize += tailen; - if (sk) + if (sk && sk_fullsock(sk)) refcount_add(tailen, &sk->sk_wmem_alloc); goto out;