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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 829F7C4360C for ; Thu, 10 Oct 2019 23:51:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5DAA8206B6 for ; Thu, 10 Oct 2019 23:51:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727133AbfJJXvE (ORCPT ); Thu, 10 Oct 2019 19:51:04 -0400 Received: from www62.your-server.de ([213.133.104.62]:39054 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725845AbfJJXvD (ORCPT ); Thu, 10 Oct 2019 19:51:03 -0400 Received: from 55.249.197.178.dynamic.dsl-lte-bonding.lssmb00p-msn.res.cust.swisscom.ch ([178.197.249.55] helo=localhost) by www62.your-server.de with esmtpsa (TLSv1.2:DHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89_1) (envelope-from ) id 1iIiCz-0001j6-HD; Fri, 11 Oct 2019 01:51:01 +0200 Date: Fri, 11 Oct 2019 01:51:01 +0200 From: Daniel Borkmann To: Andrii Nakryiko Cc: bpf@vger.kernel.org, netdev@vger.kernel.org, ast@fb.com, andrii.nakryiko@gmail.com, kernel-team@fb.com Subject: Re: [PATCH v2 bpf-next 0/2] Track read-only map contents as known scalars in BPF verifiers Message-ID: <20191010235101.GB20202@pc-63.home> References: <20191009201458.2679171-1-andriin@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191009201458.2679171-1-andriin@fb.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-Authenticated-Sender: daniel@iogearbox.net X-Virus-Scanned: Clear (ClamAV 0.101.4/25598/Thu Oct 10 10:50:35 2019) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, Oct 09, 2019 at 01:14:56PM -0700, Andrii Nakryiko wrote: > With BPF maps supporting direct map access (currently, array_map w/ single > element, used for global data) that are read-only both from system call and > BPF side, it's possible for BPF verifier to track its contents as known > constants. > > Now it's possible for user-space control app to pre-initialize read-only map > (e.g., for .rodata section) with user-provided flags and parameters and rely > on BPF verifier to detect and eliminate dead code resulting from specific > combination of input parameters. > > v1->v2: > - BPF_F_RDONLY means nothing, stick to just map->frozen (Daniel); > - stick to passing just offset into map_direct_value_addr (Martin). > > Andrii Nakryiko (2): > bpf: track contents of read-only maps as scalars > selftests/bpf: add read-only map values propagation tests > > kernel/bpf/verifier.c | 57 ++++++++++- > .../selftests/bpf/prog_tests/rdonly_maps.c | 99 +++++++++++++++++++ > .../selftests/bpf/progs/test_rdonly_maps.c | 83 ++++++++++++++++ > 3 files changed, 237 insertions(+), 2 deletions(-) > create mode 100644 tools/testing/selftests/bpf/prog_tests/rdonly_maps.c > create mode 100644 tools/testing/selftests/bpf/progs/test_rdonly_maps.c Applied, thanks!