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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 27DEDC3A5A4 for ; Tue, 27 Aug 2019 08:01:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E9BBF206BA for ; Tue, 27 Aug 2019 08:01:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566892914; bh=Bmw78oSogBHQLfgSUraUOxCmqO6IB2RkUbvaOhQYRMk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=JY/scVfjiTxov1W/XAMhXGLwRpqT/b6pW9TCiDMFKrtMXfX419jTxTp/uynAsdItJ 3km/yDi7mBudDYkSCzJMUDgJ1qbQREHdFBGIpvrjcdzDjo9HvTaUUH+7XXJKlBqVlF e/LWcLhUTAE7fDIkzXGDGRXLg/MJcauYB6c2wOYw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731851AbfH0IBw (ORCPT ); Tue, 27 Aug 2019 04:01:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:58130 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730187AbfH0IBl (ORCPT ); Tue, 27 Aug 2019 04:01:41 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 596E2206BA; Tue, 27 Aug 2019 08:01:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566892900; bh=Bmw78oSogBHQLfgSUraUOxCmqO6IB2RkUbvaOhQYRMk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=N3W30cjZCPa+SA2CJQ/v2jPNixL/8i0EHal9hDLehr2hEOU90mOUeT4StZts8wM/U sb4SHLK9zMBrNuGHCpExjUSPvNKWqCHSApAwKqos4IXGMzsJSZd/kBn5ailT/j7Seq Amb8EgYL2HCD6u6l9+n0tTTXk3/TRKOUi2sxkLaY= 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 5.2 016/162] libbpf: sanitize VAR to conservative 1-byte INT Date: Tue, 27 Aug 2019 09:49:04 +0200 Message-Id: <20190827072738.902407844@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190827072738.093683223@linuxfoundation.org> References: <20190827072738.093683223@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ 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