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=-4.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 90B40C1975A for ; Tue, 17 Mar 2020 20:38:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4E0132073E for ; Tue, 17 Mar 2020 20:38:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584477529; bh=VHD4rAkbSaoUgPN7k0Fur2+SkX2RyJSccvlCjAt8Z18=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=AuBSM6nThmr8E8s+nSUqjz23KMqKqoxLF7IpwxeSNOnQK+v+MWzV5hfCaTV13nazx 2ekmsMY9gNOWBC5upmKi01+NZRzk+7m2YTyceFWLy3cmX9/JOZ9aPyz2q4Tos0/OwK ACYplO6iM+CKKlAUu7wSxGTTS6Ht+1fHugvhJ3+Q= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726730AbgCQUit (ORCPT ); Tue, 17 Mar 2020 16:38:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:54978 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726680AbgCQUis (ORCPT ); Tue, 17 Mar 2020 16:38:48 -0400 Received: from kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com (unknown [163.114.132.4]) (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 A52CA20714; Tue, 17 Mar 2020 20:38:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584477528; bh=VHD4rAkbSaoUgPN7k0Fur2+SkX2RyJSccvlCjAt8Z18=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=j6QYJU1jNGkpJS9it+Rc/9eP02/CVKgqnMDKGMgGnIa5kKu7cIkyA84Kxgc/KgMmH qX6KCucXiJJyAuWbaBrxwWz+F4/Vov99VBN1zirFc8zHBizkJ1cfUOWRurMKv7Qn/K kVs717U8rve2VPQA51UykNqcf7PV7MckDlgZFWEw= Date: Tue, 17 Mar 2020 13:38:46 -0700 From: Jakub Kicinski To: Jesper Dangaard Brouer Cc: sameehj@amazon.com, netdev@vger.kernel.org, bpf@vger.kernel.org, zorik@amazon.com, akiyano@amazon.com, gtzalik@amazon.com, Toke =?UTF-8?B?SMO4aWxhbmQtSsO4cmdlbnNlbg==?= , Daniel Borkmann , Alexei Starovoitov , John Fastabend , Alexander Duyck , Jeff Kirsher , David Ahern , Willem de Bruijn , Ilias Apalodimas , Lorenzo Bianconi Subject: Re: [PATCH RFC v1 09/15] xdp: clear grow memory in bpf_xdp_adjust_tail() Message-ID: <20200317133846.3c7fffe3@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: <158446619342.702578.1522482431365026926.stgit@firesoul> References: <158446612466.702578.2795159620575737080.stgit@firesoul> <158446619342.702578.1522482431365026926.stgit@firesoul> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Tue, 17 Mar 2020 18:29:53 +0100 Jesper Dangaard Brouer wrote: > To reviewers: Need some opinions if this is needed? > > (TODO: Squash patch) I'd vote we don't clear, since we don't clear in adjust head. We could also add some wrapper around memset() which could be compiled out based on some CONFIG_ but that could be seen as just moving the responsibility onto the user.. > diff --git a/net/core/filter.c b/net/core/filter.c > index 0ceddee0c678..669f29992177 100644 > --- a/net/core/filter.c > +++ b/net/core/filter.c > @@ -3432,6 +3432,12 @@ BPF_CALL_2(bpf_xdp_adjust_tail, struct xdp_buff *, xdp, int, offset) > if (unlikely(data_end < xdp->data + ETH_HLEN)) > return -EINVAL; > > + // XXX: To reviewers: How paranoid are we? Do we really need to > + /* clear memory area on grow, as in-theory can contain uninit kmem */ > + if (offset > 0) { > + memset(xdp->data_end, 0, offset); > + } > + > xdp->data_end = data_end; > > return 0; > >