From patchwork Mon May 31 13:15:25 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 450825 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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, 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 61D4FC4708F for ; Mon, 31 May 2021 14:59:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 49C9C610A1 for ; Mon, 31 May 2021 14:59:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232573AbhEaPBH (ORCPT ); Mon, 31 May 2021 11:01:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:51048 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234278AbhEaO5U (ORCPT ); Mon, 31 May 2021 10:57:20 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 16775613AB; Mon, 31 May 2021 14:00:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1622469628; bh=4r8bIelEgvVoFC7a91sRzVYYVuzGkI8KocGoHrnPf0I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gEjPpYqGfXWPq0kGuitmZDLUp2mGwxgFZq7cNxb3U2juVLdcqxHWFdE3xtn0CftRR x4wPiqYQdJJu+xezu2ZSbryTvTF+rcKo70EGu6v/Vlez//mtO57O9cFNEUAMbTnk+T 4yt7hSPbrrdjjzTwvK77EwjIRnbakAst0U+bZ4D0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jussi Maki , Daniel Borkmann , Sasha Levin Subject: [PATCH 5.12 270/296] bpf: Set mac_len in bpf_skb_change_head Date: Mon, 31 May 2021 15:15:25 +0200 Message-Id: <20210531130712.815676032@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210531130703.762129381@linuxfoundation.org> References: <20210531130703.762129381@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jussi Maki [ Upstream commit 84316ca4e100d8cbfccd9f774e23817cb2059868 ] The skb_change_head() helper did not set "skb->mac_len", which is problematic when it's used in combination with skb_redirect_peer(). Without it, redirecting a packet from a L3 device such as wireguard to the veth peer device will cause skb->data to point to the middle of the IP header on entry to tcp_v4_rcv() since the L2 header is not pulled correctly due to mac_len=0. Fixes: 3a0af8fd61f9 ("bpf: BPF for lightweight tunnel infrastructure") Signed-off-by: Jussi Maki Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20210519154743.2554771-2-joamaki@gmail.com Signed-off-by: Sasha Levin --- net/core/filter.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/core/filter.c b/net/core/filter.c index 9323d34d34cc..52f4359efbd2 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3782,6 +3782,7 @@ static inline int __bpf_skb_change_head(struct sk_buff *skb, u32 head_room, __skb_push(skb, head_room); memset(skb->data, 0, head_room); skb_reset_mac_header(skb); + skb_reset_mac_len(skb); } return ret;