From patchwork Mon Dec 28 12:40:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 353699 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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham 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 EC4D8C433E0 for ; Mon, 28 Dec 2020 14:02:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B5DC6205CB for ; Mon, 28 Dec 2020 14:02:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2436766AbgL1OCG (ORCPT ); Mon, 28 Dec 2020 09:02:06 -0500 Received: from mail.kernel.org ([198.145.29.99]:35908 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2436760AbgL1OCF (ORCPT ); Mon, 28 Dec 2020 09:02:05 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7DECE20715; Mon, 28 Dec 2020 14:01:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609164085; bh=U0x52ZTbZHpuD3FlCFf6BKzXv+nrYvKYlN1jlfRTMuI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=omC1pPgjjiWTMT25/SkmGy3XJIwvefWmnexZJEizzIwlaUORZgLJVzB2ngVwpGTx+ 05KZXO3Mx1aI52Jhzrg1SxT5GTl4izHqOvuxbOto+Vr+Mq2SUNgygB0jWgRPZR3lfA QOI49WMZ1MLcmg1LEis7KHxQ4c4ctQcaYIeeZ1Qg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andrii Nakryiko , Alexei Starovoitov , Sasha Levin Subject: [PATCH 5.10 055/717] libbpf: Fix BTF data layout checks and allow empty BTF Date: Mon, 28 Dec 2020 13:40:53 +0100 Message-Id: <20201228125023.630228905@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201228125020.963311703@linuxfoundation.org> References: <20201228125020.963311703@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Andrii Nakryiko [ Upstream commit d8123624506cd62730c9cd9c7672c698e462703d ] Make data section layout checks stricter, disallowing overlap of types and strings data. Additionally, allow BTFs with no type data. There is nothing inherently wrong with having BTF with no types (put potentially with some strings). This could be a situation with kernel module BTFs, if module doesn't introduce any new type information. Also fix invalid offset alignment check for btf->hdr->type_off. Fixes: 8a138aed4a80 ("bpf: btf: Add BTF support to libbpf") Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20201105043402.2530976-8-andrii@kernel.org Signed-off-by: Sasha Levin --- tools/lib/bpf/btf.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 231b07203e3d2..987c1515b828b 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -215,22 +215,18 @@ static int btf_parse_hdr(struct btf *btf) return -EINVAL; } - if (meta_left < hdr->type_off) { - pr_debug("Invalid BTF type section offset:%u\n", hdr->type_off); + if (meta_left < hdr->str_off + hdr->str_len) { + pr_debug("Invalid BTF total size:%u\n", btf->raw_size); return -EINVAL; } - if (meta_left < hdr->str_off) { - pr_debug("Invalid BTF string section offset:%u\n", hdr->str_off); + if (hdr->type_off + hdr->type_len > hdr->str_off) { + pr_debug("Invalid BTF data sections layout: type data at %u + %u, strings data at %u + %u\n", + hdr->type_off, hdr->type_len, hdr->str_off, hdr->str_len); return -EINVAL; } - if (hdr->type_off >= hdr->str_off) { - pr_debug("BTF type section offset >= string section offset. No type?\n"); - return -EINVAL; - } - - if (hdr->type_off & 0x02) { + if (hdr->type_off % 4) { pr_debug("BTF type section is not aligned to 4 bytes\n"); return -EINVAL; }