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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 DDF5EC17441 for ; Mon, 11 Nov 2019 18:52:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ABB56214E0 for ; Mon, 11 Nov 2019 18:52:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573498350; bh=jpbIPP49zvHFC2TMrGanJSqYYGPqKzLDrVU9Or1jmEA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=RQ7erOEw7jpvbxUu8dlKBNZUDH2tdiDW1iX3dHKKBxCA8HyYF80y0TQXNNeQgTOvO i/d4Qf3BYzCzOFUIkm7kva+Abf2xP3fvRV75VtLybSI+vHwxEt96e1BIaakK5UiRL6 HSDQeVHKcYqi8O2D+W2CrcUfQ3ZmZtaKDtqFXXtY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730503AbfKKSw3 (ORCPT ); Mon, 11 Nov 2019 13:52:29 -0500 Received: from mail.kernel.org ([198.145.29.99]:46778 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729608AbfKKSw0 (ORCPT ); Mon, 11 Nov 2019 13:52:26 -0500 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 8C97E214E0; Mon, 11 Nov 2019 18:52:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573498346; bh=jpbIPP49zvHFC2TMrGanJSqYYGPqKzLDrVU9Or1jmEA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ioFb8Cl9c4GfSESA0vP+eVSdva2JNMRZpTxDYi/bPnZmQBuzns8to8YO96pxYplgO 7dJofPN+LnsEw8OnKxceHhqWBOOfncvSrV4rO060gCMZTySjVSvKD6biXNIAgRWrk7 365L7GLPSGwA5QOHuJUDf3e9ZXp4A1FkSd/DNZ7A= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jiri Benc , Alexei Starovoitov , Peter Oskolkov , Sasha Levin Subject: [PATCH 5.3 093/193] bpf: lwtunnel: Fix reroute supplying invalid dst Date: Mon, 11 Nov 2019 19:27:55 +0100 Message-Id: <20191111181508.002089805@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191111181459.850623879@linuxfoundation.org> References: <20191111181459.850623879@linuxfoundation.org> User-Agent: quilt/0.66 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 From: Jiri Benc [ Upstream commit 9e8acd9c44a0dd52b2922eeb82398c04e356c058 ] The dst in bpf_input() has lwtstate field set. As it is of the LWTUNNEL_ENCAP_BPF type, lwtstate->data is struct bpf_lwt. When the bpf program returns BPF_LWT_REROUTE, ip_route_input_noref is directly called on this skb. This causes invalid memory access, as ip_route_input_slow calls skb_tunnel_info(skb) that expects the dst->lwstate->data to be struct ip_tunnel_info. This results to struct bpf_lwt being accessed as struct ip_tunnel_info. Drop the dst before calling the IP route input functions (both for IPv4 and IPv6). Reported by KASAN. Fixes: 3bd0b15281af ("bpf: add handling of BPF_LWT_REROUTE to lwt_bpf.c") Signed-off-by: Jiri Benc Signed-off-by: Alexei Starovoitov Acked-by: Peter Oskolkov Link: https://lore.kernel.org/bpf/111664d58fe4e9dd9c8014bb3d0b2dab93086a9e.1570609794.git.jbenc@redhat.com Signed-off-by: Sasha Levin --- net/core/lwt_bpf.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/net/core/lwt_bpf.c b/net/core/lwt_bpf.c index f93785e5833c1..74cfb8b5ab330 100644 --- a/net/core/lwt_bpf.c +++ b/net/core/lwt_bpf.c @@ -88,11 +88,16 @@ static int bpf_lwt_input_reroute(struct sk_buff *skb) int err = -EINVAL; if (skb->protocol == htons(ETH_P_IP)) { + struct net_device *dev = skb_dst(skb)->dev; struct iphdr *iph = ip_hdr(skb); + dev_hold(dev); + skb_dst_drop(skb); err = ip_route_input_noref(skb, iph->daddr, iph->saddr, - iph->tos, skb_dst(skb)->dev); + iph->tos, dev); + dev_put(dev); } else if (skb->protocol == htons(ETH_P_IPV6)) { + skb_dst_drop(skb); err = ipv6_stub->ipv6_route_input(skb); } else { err = -EAFNOSUPPORT; -- 2.20.1