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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 085F2C2D0EA for ; Wed, 8 Apr 2020 11:53:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CC86020780 for ; Wed, 8 Apr 2020 11:53:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="XZRCGjBC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728784AbgDHLxT (ORCPT ); Wed, 8 Apr 2020 07:53:19 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:24564 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726901AbgDHLxS (ORCPT ); Wed, 8 Apr 2020 07:53:18 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1586346797; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=L9pM6e9PkD9AKDv2RUiB8tixTD0EYesJFyWKVCEek7M=; b=XZRCGjBCWeyFBAFtBR+M+5AXPY2UKNH7WJCU09bjjSRRxgHUI16C/7EXN3R92HNZxKpmdn qn41JmV7heHNW4UNRsouNgAL2UUCNMaNjgONM0mywzuNausNMzd9xMHA8kjM0QoYuZ0Pby 7+i0Gghrtw4m7VFZ6rLh7IGZearlTzg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-492-n196LA3fPC-Ym83aNacAVA-1; Wed, 08 Apr 2020 07:53:15 -0400 X-MC-Unique: n196LA3fPC-Ym83aNacAVA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5CE0010CE781; Wed, 8 Apr 2020 11:53:13 +0000 (UTC) Received: from firesoul.localdomain (unknown [10.40.208.40]) by smtp.corp.redhat.com (Postfix) with ESMTP id C07B01BC6D; Wed, 8 Apr 2020 11:53:07 +0000 (UTC) Received: from [192.168.42.3] (localhost [IPv6:::1]) by firesoul.localdomain (Postfix) with ESMTP id D2CB8300020FA; Wed, 8 Apr 2020 13:53:06 +0200 (CEST) Subject: [PATCH RFC v2 30/33] xdp: clear grow memory in bpf_xdp_adjust_tail() From: Jesper Dangaard Brouer To: sameehj@amazon.com Cc: Jesper Dangaard Brouer , netdev@vger.kernel.org, bpf@vger.kernel.org, zorik@amazon.com, akiyano@amazon.com, gtzalik@amazon.com, =?utf-8?q?Toke_H=C3=B8iland-J=C3=B8rgensen?= , Daniel Borkmann , Alexei Starovoitov , John Fastabend , Alexander Duyck , Jeff Kirsher , David Ahern , Willem de Bruijn , Ilias Apalodimas , Lorenzo Bianconi , Saeed Mahameed Date: Wed, 08 Apr 2020 13:53:06 +0200 Message-ID: <158634678679.707275.5039642404868230051.stgit@firesoul> In-Reply-To: <158634658714.707275.7903484085370879864.stgit@firesoul> References: <158634658714.707275.7903484085370879864.stgit@firesoul> User-Agent: StGit/0.19 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Clearing memory of tail when grow happens, because it is too easy to write a XDP_PASS program that extend the tail, which expose this memory to users that can run tcpdump. Signed-off-by: Jesper Dangaard Brouer --- net/core/filter.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/core/filter.c b/net/core/filter.c index 4d58a147eed0..a8674f2a0e24 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3445,6 +3445,11 @@ BPF_CALL_2(bpf_xdp_adjust_tail, struct xdp_buff *, xdp, int, offset) if (unlikely(data_end < xdp->data + ETH_HLEN)) return -EINVAL; + /* Clear memory area on grow, can contain uninit kernel memory */ + if (offset > 0) { + memset(xdp->data_end, 0, offset); + } + xdp->data_end = data_end; return 0;