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=unavailable 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 AE9BDC433E0 for ; Thu, 14 May 2020 10:51:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 85C2620575 for ; Thu, 14 May 2020 10:51:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="JTSYjxCJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727845AbgENKvm (ORCPT ); Thu, 14 May 2020 06:51:42 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:30702 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726169AbgENKvl (ORCPT ); Thu, 14 May 2020 06:51:41 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589453500; 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=QgmQQ3BdP3fG2j1xwjXam7QeuzlwY8kv6oC0rf1kJv0=; b=JTSYjxCJ9dLujwZ7nF/RSP03zsnzB9vuHw62aEW2hEAogBd33lBc3CRuIXvelibGUdbH4h S1NRzYNSYqefcVut1ocZ4mL5MZVKORC36F4rsmO0ajPsnR1z77lnWRJopcxmt+JTnYE+I8 8ZqfJ6j7ajLEbhQZoUMQAe+/ZeejFbI= 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-274-LpzPMr23P4mThsJv9sSGdg-1; Thu, 14 May 2020 06:51:39 -0400 X-MC-Unique: LpzPMr23P4mThsJv9sSGdg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3EF58100CCC0; Thu, 14 May 2020 10:51:37 +0000 (UTC) Received: from firesoul.localdomain (unknown [10.40.208.32]) by smtp.corp.redhat.com (Postfix) with ESMTP id 93D946A977; Thu, 14 May 2020 10:51:31 +0000 (UTC) Received: from [192.168.42.3] (localhost [IPv6:::1]) by firesoul.localdomain (Postfix) with ESMTP id 74F09300020FC; Thu, 14 May 2020 12:51:30 +0200 (CEST) Subject: [PATCH net-next v4 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, =?utf-8?q?Toke_H=C3=B8iland-J=C3=B8rgensen?= , Daniel Borkmann , Alexei Starovoitov , "David S. Miller" , John Fastabend , Alexander Duyck , Jeff Kirsher , David Ahern , Ilias Apalodimas , Lorenzo Bianconi , Saeed Mahameed , Tariq Toukan Date: Thu, 14 May 2020 12:51:30 +0200 Message-ID: <158945349039.97035.5262100484553494.stgit@firesoul> In-Reply-To: <158945314698.97035.5286827951225578467.stgit@firesoul> References: <158945314698.97035.5286827951225578467.stgit@firesoul> User-Agent: StGit/0.19 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@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 Acked-by: Toke Høiland-Jørgensen --- net/core/filter.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/core/filter.c b/net/core/filter.c index ec3ab2e2d800..691235208e0b 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3427,6 +3427,10 @@ 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;