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=-7.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,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 33FC1C433DB for ; Thu, 28 Jan 2021 23:15:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0732364DED for ; Thu, 28 Jan 2021 23:15:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231658AbhA1XP3 (ORCPT ); Thu, 28 Jan 2021 18:15:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231626AbhA1XP1 (ORCPT ); Thu, 28 Jan 2021 18:15:27 -0500 Received: from mail-il1-x12f.google.com (mail-il1-x12f.google.com [IPv6:2607:f8b0:4864:20::12f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D5D65C061573; Thu, 28 Jan 2021 15:14:44 -0800 (PST) Received: by mail-il1-x12f.google.com with SMTP id q5so6891645ilc.10; Thu, 28 Jan 2021 15:14:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:message-id:in-reply-to:references:subject :mime-version:content-transfer-encoding; bh=tUOoiixOlHERyRclinULi6EGJX0DLXiHdqYf6TmzoPQ=; b=Fm2YGUDHFksDPi+zCTrDoTv/AwkUmucbRonRbQXwTYHnp9Zyh4WPrKwhL0XcbXsMXF RBwUNNkd/fmEciPrFCnTOo6bEbsAQriCI4JN3tlwZWb2NUlFsJQAwpprEbcYHbUrY/fh DCwk2Z/Zgq9icKxvU4wNajkW/9QCRzqN9LWIqmo8LXOK4sAWaCj6DCm9iidiiWr41VT5 3XR9AtKVepR6hEk0e/PfbRy9XOex7jsAKuPOG0It0XwioxqsAQ3U7Z63iohIWq0K1stl vRzw67E+uA0EA5XePlpOO3sxgBaGjlh1F/QelFYDBPBPwhUEyCcG0OMfQ5CwxXABUNCM ffRA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:message-id:in-reply-to :references:subject:mime-version:content-transfer-encoding; bh=tUOoiixOlHERyRclinULi6EGJX0DLXiHdqYf6TmzoPQ=; b=ZUNqqHGogSnSx+h3/EBn0QDPAJAFbpBMQV7sAWUlKGiUddtbsdhavp2RrPk6WcAxQo D+Pn28m8i7u8sVGlOZMVzb/kzhRPbu6wc6rGacGNpgBToy/AbAvE2mkwU2pE7wXNzfBi aV8vfsIjWP3L8g1nWo25nEvhjiDoJaq+LFsN0wYcDPv7tNHt6h7Ue2QBaPVdgQvJ4bTt J7VP1yIyTGh51dxjMq8pdqbzp7gQvIbDtXH4TH13qLJY+uQ1ijoXYVKrmf6YKKtgSQDa fgUdJIt+2HsYRwjGmN9tw0L7rEhKBvwwW4vQWCijUlyINcAc1gmznTycksvlEFJmm0MN gUSw== X-Gm-Message-State: AOAM531byHe3ilDwElIlslxSsWQzQxdT2oaAQSNl09H2meXTNODxGhuX VrdWpr4cdCEGT8Sxtdm12Js= X-Google-Smtp-Source: ABdhPJzFXsjEolV4b7EPgRrMdbj/cdHkAXQcxOHKNhkq36+IQ2BOvwrqNuNVAls2LoXRx4HRfH+grw== X-Received: by 2002:a05:6e02:1608:: with SMTP id t8mr1077080ilu.79.1611875684261; Thu, 28 Jan 2021 15:14:44 -0800 (PST) Received: from localhost ([172.243.146.206]) by smtp.gmail.com with ESMTPSA id f6sm3067549iov.45.2021.01.28.15.14.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 28 Jan 2021 15:14:43 -0800 (PST) Date: Thu, 28 Jan 2021 15:14:36 -0800 From: John Fastabend To: Hangbin Liu , John Fastabend Cc: bpf@vger.kernel.org, netdev@vger.kernel.org, =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= , Jiri Benc , Jesper Dangaard Brouer , Eelco Chaudron , ast@kernel.org, Daniel Borkmann , Lorenzo Bianconi , David Ahern , Andrii Nakryiko , Alexei Starovoitov , Maciej Fijalkowski Message-ID: <6013455cc1e36_f9c12083b@john-XPS-13-9370.notmuch> In-Reply-To: <20210128035300.GQ1421720@Leo-laptop-t470s> References: <20210122074652.2981711-1-liuhangbin@gmail.com> <20210125124516.3098129-1-liuhangbin@gmail.com> <20210125124516.3098129-6-liuhangbin@gmail.com> <6011e82feb2_a0fd920881@john-XPS-13-9370.notmuch> <20210128035300.GQ1421720@Leo-laptop-t470s> Subject: Re: [PATCHv17 bpf-next 5/6] selftests/bpf: Add verifier tests for bpf arg ARG_CONST_MAP_PTR_OR_NULL Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hangbin Liu wrote: > On Wed, Jan 27, 2021 at 02:24:47PM -0800, John Fastabend wrote: > > [...] > > > > > +{ > > > + "ARG_CONST_MAP_PTR_OR_NULL: null pointer for ex_map", > > > + .insns = { > > > + BPF_MOV64_IMM(BPF_REG_1, 0), > > > + /* bpf_redirect_map_multi arg1 (in_map) */ > > > + BPF_LD_MAP_FD(BPF_REG_1, 0), > > > + /* bpf_redirect_map_multi arg2 (ex_map) */ > > > + BPF_MOV64_IMM(BPF_REG_2, 0), > > > + /* bpf_redirect_map_multi arg3 (flags) */ > > > + BPF_MOV64_IMM(BPF_REG_3, 0), > > > + BPF_EMIT_CALL(BPF_FUNC_redirect_map_multi), > > > + BPF_EXIT_INSN(), > > > + }, > > > + .fixup_map_devmap = { 1 }, > > > + .result = ACCEPT, > > > + .prog_type = BPF_PROG_TYPE_XDP, > > > + .retval = 4, > > > > Do we need one more case where this is map_or_null? In above > > ex_map will be scalar tnum_const=0 and be exactly a null. This > > will push verifier here, > > > > meta->map_ptr = register_is_null(reg) ? NULL : reg->map_ptr; > > > > In the below case it is known to be not null. > > > > Is it also interesting to have a case where register_is_null(reg) > > check fails and reg->map_ptr is set, but may be null. > > Hi John, > > I'm not familiar with the test_verifier syntax. Doesn't > BPF_LD_MAP_FD(BPF_REG_1, 0) just assign the register with map NULL? On second thought because we are only running the verifier here and not actually calling the helper I guess both paths are in fact covered here. Acked-by: John Fastabend