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=-2.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,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 878B7C433E0 for ; Thu, 28 Jan 2021 04:07:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4137364D92 for ; Thu, 28 Jan 2021 04:07:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231363AbhA1EG4 (ORCPT ); Wed, 27 Jan 2021 23:06:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50404 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231299AbhA1EFc (ORCPT ); Wed, 27 Jan 2021 23:05:32 -0500 Received: from mail-pj1-x102f.google.com (mail-pj1-x102f.google.com [IPv6:2607:f8b0:4864:20::102f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 85BC3C0617AB; Wed, 27 Jan 2021 19:53:47 -0800 (PST) Received: by mail-pj1-x102f.google.com with SMTP id cq1so3079965pjb.4; Wed, 27 Jan 2021 19:53:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=vL2Ls/K94DeV6njPMNfjB8BEObaZUQsRgrO5DBIVlqM=; b=Q4JbkF8MvUQcA+j2Fl1/8WFHpjVicak5lU39i8WrOCah3GfZrLnhHkSIratFBbWfND FV55Y+d6ifPevS0yp4si2ndwtaksmcOXpCX395FnAMwGtu6I0L2mG5I2QEInhu58snWQ sCZM2+cLYU3kKbaS9N+OyfpNwOIZKqYnSBzRGVB2rjECMlAWxBCyEzhOUCso071oh0oY 6UCpKuxoSIyyDMCmmqbX6vH+U8w7XwSbLr15b+IVSfh4gqrqeKhip/tDrlnTAWiS2hJY ZrXbdH9u5jCo2VZ7M7LEJzV0Gdu5AsoYukgGp6YB3g3kou0YFKNOKI2kSLcs7cmY1PPX EY5A== 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:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=vL2Ls/K94DeV6njPMNfjB8BEObaZUQsRgrO5DBIVlqM=; b=TL36t5dT1LLDLDEdZfMIjfTWABCf8YG95vjNvseQ8UJE2rtjCcr0XRPyy/hpKGGctb kp9qLv1s3bDV774HQBWisvrOU1y/svliQnfdshb6CoBcaMzhyW8OOa35sj0pPd4PKAW/ VbAAXrtY3g0DXXbIzqpQyfZpiMuvsvoVFi0RIwt6jgtNqEgtPU/4A27/HKtVv0d9LCnm Fz+kR5XbkuJjji6RTMga99ElOqGK++1xyK9SqNai4c5ypIlECV96J8ur/jN6N/iwkbba cFdGgIf03BYR/phvyrOeUBJF1D6njazxyo36SWLCbWUcQ56ahGiJNcvKjjoRv3hICDoy MlqA== X-Gm-Message-State: AOAM530+0Gjq150ZacuXbGuJt8HFTWpcqv8ZzfsBJ2cZy9Vw8qjTIUfA 2Tb6FeSbHhy/1bAOuwcIxMk= X-Google-Smtp-Source: ABdhPJxvy3q8H2306Ycyakn+l2HhardN2cj2y5jBnKXTt04ZrCDa/tUlj8oyBs0K2Q1TRw+cK4gFXw== X-Received: by 2002:a17:90a:1109:: with SMTP id d9mr9152958pja.94.1611806027035; Wed, 27 Jan 2021 19:53:47 -0800 (PST) Received: from Leo-laptop-t470s ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id b17sm3603179pfo.151.2021.01.27.19.53.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 27 Jan 2021 19:53:46 -0800 (PST) Date: Thu, 28 Jan 2021 11:53:00 +0800 From: Hangbin Liu To: John Fastabend Cc: bpf@vger.kernel.org, netdev@vger.kernel.org, Toke =?iso-8859-1?Q?H=F8iland-J=F8rgensen?= , Jiri Benc , Jesper Dangaard Brouer , Eelco Chaudron , ast@kernel.org, Daniel Borkmann , Lorenzo Bianconi , David Ahern , Andrii Nakryiko , Alexei Starovoitov , Maciej Fijalkowski Subject: Re: [PATCHv17 bpf-next 5/6] selftests/bpf: Add verifier tests for bpf arg ARG_CONST_MAP_PTR_OR_NULL Message-ID: <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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6011e82feb2_a0fd920881@john-XPS-13-9370.notmuch> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 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? Thanks hangbin