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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 0BE83C32750 for ; Wed, 14 Aug 2019 02:11:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C748521744 for ; Wed, 14 Aug 2019 02:11:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565748694; bh=Qxzn1GhQkt3VpBDtZ5IfDFsMDOoiGdj2MAiQd54afUo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=OjBuheJAubBRd/l8vEFjRVzAThPpdR89lkk8LCe3w6iWaObfxeoZ+1R+qvFMisR96 G1gyRqfdzWgRNsqkicAjPy7dZjLkatCDiNfOe3hWdXEO8BCFG4yR74JnU4Su8KxSOz YueSXyXlNkjOPt9HKbe91Oli+LvPcX4AONn7S52M= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727493AbfHNCLa (ORCPT ); Tue, 13 Aug 2019 22:11:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:43650 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727410AbfHNCLZ (ORCPT ); Tue, 13 Aug 2019 22:11:25 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4B5F32084D; Wed, 14 Aug 2019 02:11:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565748684; bh=Qxzn1GhQkt3VpBDtZ5IfDFsMDOoiGdj2MAiQd54afUo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jSXTl9IseVqvzEksIssa5/qzWzmHbWYxMJGINlCEPhhnwznfTzQFVM/zf2l2YJoQ7 qe+c5/G0XxLxMc+sClvo9znV0kmQXkMAkQlbWPd3Az1wKEdqWV0MjdLSZcHwxrdWIM El1ilb0Xb1WDgtQTerLfyZVTYv2r8UvTIc1c+dtU= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Andrii Nakryiko , Alexei Starovoitov , Sasha Levin , netdev@vger.kernel.org, bpf@vger.kernel.org Subject: [PATCH AUTOSEL 5.2 020/123] libbpf: sanitize VAR to conservative 1-byte INT Date: Tue, 13 Aug 2019 22:09:04 -0400 Message-Id: <20190814021047.14828-20-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190814021047.14828-1-sashal@kernel.org> References: <20190814021047.14828-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andrii Nakryiko [ Upstream commit 1d4126c4e1190d2f7d3f388552f9bd17ae0c64fc ] If VAR in non-sanitized BTF was size less than 4, converting such VAR into an INT with size=4 will cause BTF validation failure due to violationg of STRUCT (into which DATASEC was converted) member size. Fix by conservatively using size=1. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- tools/lib/bpf/libbpf.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 3865a5d272514..77e14d9954796 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -1044,8 +1044,13 @@ static void bpf_object__sanitize_btf(struct bpf_object *obj) if (!has_datasec && kind == BTF_KIND_VAR) { /* replace VAR with INT */ t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0); - t->size = sizeof(int); - *(int *)(t+1) = BTF_INT_ENC(0, 0, 32); + /* + * using size = 1 is the safest choice, 4 will be too + * big and cause kernel BTF validation failure if + * original variable took less than 4 bytes + */ + t->size = 1; + *(int *)(t+1) = BTF_INT_ENC(0, 0, 8); } else if (!has_datasec && kind == BTF_KIND_DATASEC) { /* replace DATASEC with STRUCT */ struct btf_var_secinfo *v = (void *)(t + 1); -- 2.20.1