From patchwork Wed Nov 18 07:16:39 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= X-Patchwork-Id: 327881 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=-15.7 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,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 E4CAFC6369E for ; Wed, 18 Nov 2020 07:17:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 892EC2467A for ; Wed, 18 Nov 2020 07:17:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="vSVKnliA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726654AbgKRHRD (ORCPT ); Wed, 18 Nov 2020 02:17:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56964 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725794AbgKRHRC (ORCPT ); Wed, 18 Nov 2020 02:17:02 -0500 Received: from mail-pf1-x444.google.com (mail-pf1-x444.google.com [IPv6:2607:f8b0:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9AE92C0613D4; Tue, 17 Nov 2020 23:17:02 -0800 (PST) Received: by mail-pf1-x444.google.com with SMTP id b63so816755pfg.12; Tue, 17 Nov 2020 23:17:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=gQiaQWe1AWIjaVTJuJBFgIAAz8j2qQ724nNHTwatFOs=; b=vSVKnliAxoFoUdps97fF/MjRhQ5PIHrwyawIWZd05AJfXApgPY82aNInmnvjBjmpan 6g+i0/Qy6UGSRQM9zy54Ys6f9FmGP/ZDKsQt10DYxTrmAYZ6taCZ4pajYYSDIY1+jUwx Pegt0N08Y39QrbAhGCun5bB5P7uMiNcTp6oV8DGaZ+alPc1c2bNwwRn5bCZ6slXQPfOZ BztFvviYFyuc/xxH2DaLwDyWTiNRsmhq+jLiUlco0fyTEFyUDE0GPz3yM5AND2yAFaub jFOCBs9sTz8PblxAWALD5mnIDHFiPyxlPjiJTMBccppvhVs120jj5nx60ZJgNUUch1bY fFgQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=gQiaQWe1AWIjaVTJuJBFgIAAz8j2qQ724nNHTwatFOs=; b=qO3xfSo3TWnt/C5lvFTkHpJ6O8ZcBnbcZfuRCbQiPFP8t8TkovZk1WDraFpH9ecMQW DYtyK8Z1PDpNe8OUmmoFXVJn4ZFKmBS+I6h4WozMAQ0fZUymmGp0cNFt1Z2xgUXasF/W bDTVUEd6cmEmQP7XJP8eCOhP/HTLJJS93R+qAQRgGOqDhACKKvvEuSSJ5uL2JBnCci43 da/KgUOBQupGxTJ1Cg2EB902KC1VNJJCLV84f+Myt+sZ1qPhTBFGVQCRlAc/MQEudkbZ HRhwFXyFWhwE4LEszbLGDCYjks3AX0pm5LvwnWMrUMb3GTJRy5NdbRnB9whNOZHRdNW1 e9iw== X-Gm-Message-State: AOAM533To9zW7U1x5r2TY7gxkE5ZbGC6odHLVvmxmLc1+CbXSC70TJ/G b1rPaxUnzkZ2I+20lKwi9c4= X-Google-Smtp-Source: ABdhPJw2gtuOIRE7j9J06MAVlG7kUBMjmQwO7oGzFjqSilAEwDBsEPJYa2gm3i+uAcaI0ozD7n0IgA== X-Received: by 2002:a65:684d:: with SMTP id q13mr7150124pgt.372.1605683822228; Tue, 17 Nov 2020 23:17:02 -0800 (PST) Received: from btopel-mobl.ger.intel.com ([192.55.55.45]) by smtp.gmail.com with ESMTPSA id e128sm23019382pfe.154.2020.11.17.23.16.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Nov 2020 23:17:01 -0800 (PST) From: =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= To: ast@kernel.org, daniel@iogearbox.net, netdev@vger.kernel.org, bpf@vger.kernel.org Cc: =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , xi.wang@gmail.com, luke.r.nels@gmail.com, linux-riscv@lists.infradead.org, andrii.nakryiko@gmail.com Subject: [PATCH bpf-next v2 2/3] selftests/bpf: Avoid running unprivileged tests with alignment requirements Date: Wed, 18 Nov 2020 08:16:39 +0100 Message-Id: <20201118071640.83773-3-bjorn.topel@gmail.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20201118071640.83773-1-bjorn.topel@gmail.com> References: <20201118071640.83773-1-bjorn.topel@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Some architectures have strict alignment requirements. In that case, the BPF verifier detects if a program has unaligned accesses and rejects them. A user can pass BPF_F_ANY_ALIGNMENT to a program to override this check. That, however, will only work when a privileged user loads a program. An unprivileged user loading a program with this flag will be rejected prior entering the verifier. Hence, it does not make sense to load unprivileged programs without strict alignment when testing the verifier. This patch avoids exactly that. Signed-off-by: Björn Töpel --- tools/testing/selftests/bpf/test_verifier.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c index 9be395d9dc64..4bfe3aa2cfc4 100644 --- a/tools/testing/selftests/bpf/test_verifier.c +++ b/tools/testing/selftests/bpf/test_verifier.c @@ -1152,6 +1152,19 @@ static void get_unpriv_disabled() static bool test_as_unpriv(struct bpf_test *test) { +#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS + /* Some architectures have strict alignment requirements. In + * that case, the BPF verifier detects if a program has + * unaligned accesses and rejects them. A user can pass + * BPF_F_ANY_ALIGNMENT to a program to override this + * check. That, however, will only work when a privileged user + * loads a program. An unprivileged user loading a program + * with this flag will be rejected prior entering the + * verifier. + */ + if (test->flags & F_NEEDS_EFFICIENT_UNALIGNED_ACCESS) + return false; +#endif return !test->prog_type || test->prog_type == BPF_PROG_TYPE_SOCKET_FILTER || test->prog_type == BPF_PROG_TYPE_CGROUP_SKB;