From patchwork Sun Sep 20 05:01:35 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Ambardar X-Patchwork-Id: 260540 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=-12.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, 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 35069C43468 for ; Sun, 20 Sep 2020 05:02:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ECFC42075A for ; Sun, 20 Sep 2020 05:02:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="pwu62dsu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726953AbgITFCQ (ORCPT ); Sun, 20 Sep 2020 01:02:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44994 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726760AbgITFCP (ORCPT ); Sun, 20 Sep 2020 01:02:15 -0400 Received: from mail-pl1-x641.google.com (mail-pl1-x641.google.com [IPv6:2607:f8b0:4864:20::641]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 42F1DC061755; Sat, 19 Sep 2020 22:02:15 -0700 (PDT) Received: by mail-pl1-x641.google.com with SMTP id u9so5182889plk.4; Sat, 19 Sep 2020 22:02:15 -0700 (PDT) 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=zf+F5l4BOBKHcTchW4Xrun/P792neDZIw8SXQYChyx8=; b=pwu62dsujY21zRrqVdCN4xjg1zMPVfJ6bpTeI2jGKrUyaJP9XUf/V73AqJmZHpxXn8 mbVW/xNIY4LRtJ9sizRS9aQhvukpMAIz4DGeK1aRK2mWyyxaPDGUMalxL351AIQTzOD7 Nwz+gUgt7h1JJgxOymrrzJLypTz13T0bBJ47O3F/FNNoYweray4pnTqbMy8J2xlbzl0S +bDbh1YNIMdGv4dcffnhn/KDboLQ0pk7F0E7eJ8T8eAtRWlKbkC9cT5wb/WfBFC3lbR4 WRpR/PQiDU5XjrCBed1T4iRYBeFBAuvYjOy+jAxxHqOgZ2BJ1bL6jO8zXj4eXyyVnbcW 0ijw== 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=zf+F5l4BOBKHcTchW4Xrun/P792neDZIw8SXQYChyx8=; b=HB0IYxxNObpOx96mR/IU9KuvWmLPWJY+w6oEG7eTKMwDCT5ahKHYdMc5b+UqiPNnzJ uLr1mgLyD5E/SIWSb/geYtWwVpJVt8b02J7Co8pCWsog214Dob2Fchuf/OCnn7AowWdt uTc9IIwYEHb9Tm/bQWYbwBsJYX8BAp7GMfD9x4WFV3oARcYCUxC1EA3eR9k5OyXR/5mr LreD2tDHhiGE924zNGXh3pA1rCKx00uNhkLXZBcBwNA+WvO9e/h5I+g8C5IoiM7frnP7 ihq2H3zMfBSNqTuStQfKGSWIEbG2n79OUNQXZAwavdzPAIDLQOkJM5fnM0tA3Kb3tdDs TW3g== X-Gm-Message-State: AOAM530hXzYuCUe8yqWtjPvPtd9/yLslYZF6lrPILdPLgN2Kxs8UsOuX jt16DXIEUEEfZBbIhG7ugoU= X-Google-Smtp-Source: ABdhPJyKvHtlZDtNBQWDrwzNX2viJkG/PDEGBhae2HyhmHWRadjwR2S9VQW+lzDLIQmvA2yAVwdPRw== X-Received: by 2002:a17:90a:fb52:: with SMTP id iq18mr19562285pjb.207.1600578134799; Sat, 19 Sep 2020 22:02:14 -0700 (PDT) Received: from localhost.localdomain ([2001:470:e92d:10:d88d:3b4f:9cac:cf18]) by smtp.gmail.com with ESMTPSA id w19sm8432556pfq.60.2020.09.19.22.02.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 19 Sep 2020 22:02:14 -0700 (PDT) From: Tony Ambardar X-Google-Original-From: Tony Ambardar To: Alexei Starovoitov , Daniel Borkmann Cc: Tony Ambardar , netdev@vger.kernel.org, bpf@vger.kernel.org, linux-arch@vger.kernel.org, Arnd Bergmann Subject: [PATCH bpf v1 3/3] libbpf: fix native endian assumption when parsing BTF Date: Sat, 19 Sep 2020 22:01:35 -0700 Message-Id: <90f81508ecc57bc0da318e0fe0f45cfe49b17ea7.1600417359.git.Tony.Ambardar@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Code in btf__parse_raw() fails to detect raw BTF of non-native endianness and assumes it must be ELF data, which then fails to parse as ELF and yields a misleading error message: root:/# bpftool btf dump file /sys/kernel/btf/vmlinux libbpf: failed to get EHDR from /sys/kernel/btf/vmlinux For example, this could occur after cross-compiling a BTF-enabled kernel for a target with non-native endianness, which is currently unsupported. Check for correct endianness and emit a clearer error message: root:/# bpftool btf dump file /sys/kernel/btf/vmlinux libbpf: non-native BTF endianness is not supported Fixes: 94a1fedd63ed ("libbpf: Add btf__parse_raw() and generic btf__parse() APIs") Signed-off-by: Tony Ambardar Acked-by: John Fastabend --- tools/lib/bpf/btf.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 7dfca7016aaa..6bdbc389b493 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -659,6 +659,12 @@ struct btf *btf__parse_raw(const char *path) err = -EIO; goto err_out; } + if (magic == __bswap_16(BTF_MAGIC)) { + /* non-native endian raw BTF */ + pr_warn("non-native BTF endianness is not supported\n"); + err = -LIBBPF_ERRNO__ENDIAN; + goto err_out; + } if (magic != BTF_MAGIC) { /* definitely not a raw BTF */ err = -EPROTO;