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=-3.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=no 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 265EDC433E0 for ; Thu, 28 May 2020 16:51:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EA4D62078C for ; Thu, 28 May 2020 16:51:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="nC7zDXfq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405190AbgE1QvI (ORCPT ); Thu, 28 May 2020 12:51:08 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:56412 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405162AbgE1QvG (ORCPT ); Thu, 28 May 2020 12:51:06 -0400 Received: from pps.filterd (m0148460.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 04SGp1OM010702 for ; Thu, 28 May 2020 09:51:05 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding : content-type; s=facebook; bh=3TIaWLg1bxvMy7zEauPdf8o8sNn+GfmcY2E9sap/3mg=; b=nC7zDXfqQy7pX2afPHrTVcBYThClkIep0mh3BFl8Oegsg018vQL0yFfMQoGKGRfDgSgX 2W55sJmLzsihcA9f/e3XL4OvVRf4HnMK0gSoC9mSGAm0ynAsmEKVALGcXGVeBM+nM9xu y9szVNLHn3o07oTXJ3NIFzk9dtzl1hLwa74= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 31ag6rgmxv-6 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Thu, 28 May 2020 09:51:05 -0700 Received: from intmgw002.08.frc2.facebook.com (2620:10d:c085:108::8) by mail.thefacebook.com (2620:10d:c085:21d::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Thu, 28 May 2020 09:50:52 -0700 Received: by devbig003.ftw2.facebook.com (Postfix, from userid 128203) id 3778137053B1; Thu, 28 May 2020 09:50:43 -0700 (PDT) Smtp-Origin-Hostprefix: devbig From: Yonghong Song Smtp-Origin-Hostname: devbig003.ftw2.facebook.com To: CC: Alexei Starovoitov , Daniel Borkmann , Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH bpf 0/2] bpf: fix a verifier issue when assigning 32bit reg states to 64bit ones Date: Thu, 28 May 2020 09:50:43 -0700 Message-ID: <20200528165043.1568623-1-yhs@fb.com> X-Mailer: git-send-email 2.24.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-FB-Internal: Safe Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.216,18.0.687 definitions=2020-05-28_03:2020-05-28,2020-05-28 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 malwarescore=0 bulkscore=0 priorityscore=1501 phishscore=0 adultscore=0 mlxscore=0 suspectscore=13 spamscore=0 mlxlogscore=412 lowpriorityscore=0 cotscore=-2147483648 clxscore=1015 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2005280117 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Commit 3f50f132d840 ("bpf: Verifier, do explicit ALU32 bounds tracking") added 32bit register states to verifier for explicit ALU32 bounds tracking. When assigning 32bit register states to 64bit register states, if 32bit register is a constant value of 0, the 64bit register smax_val will get U32_MAX(0xffffFFFF). Such an inprecise information may impact downward verification. Patch #1 has detailed explanation of the program and how to fix it. Patch #2 provides a verifier test to cover the change. Yonghong Song (2): bpf: fix a verifier issue when assigning 32bit reg states to 64bit tools/bpf: add a verifier test for assigning 32bit reg states to 64bit kernel/bpf/verifier.c | 3 +++ tools/testing/selftests/bpf/verifier/bounds.c | 22 +++++++++++++++++++ 2 files changed, 25 insertions(+) --=20 2.24.1