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=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 6FC02C3A59D for ; Mon, 19 Aug 2019 10:35:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4B45320843 for ; Mon, 19 Aug 2019 10:35:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727455AbfHSKfp (ORCPT ); Mon, 19 Aug 2019 06:35:45 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:5154 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727345AbfHSKfV (ORCPT ); Mon, 19 Aug 2019 06:35:21 -0400 Received: from DGGEMS401-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 755C8A8FFE39C71DE2F0; Mon, 19 Aug 2019 18:35:17 +0800 (CST) Received: from architecture4.huawei.com (10.140.130.215) by smtp.huawei.com (10.3.19.201) with Microsoft SMTP Server (TLS) id 14.3.439.0; Mon, 19 Aug 2019 18:35:11 +0800 From: Gao Xiang To: Chao Yu , Greg Kroah-Hartman , , CC: LKML , , "Chao Yu" , Miao Xie , , Fang Wei , Gao Xiang , Subject: [PATCH 6/6] staging: erofs: avoid endless loop of invalid lookback distance 0 Date: Mon, 19 Aug 2019 18:34:26 +0800 Message-ID: <20190819103426.87579-7-gaoxiang25@huawei.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190819103426.87579-1-gaoxiang25@huawei.com> References: <20190819080218.GA42231@138> <20190819103426.87579-1-gaoxiang25@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.140.130.215] X-CFilter-Loop: Reflected Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org As reported by erofs-utils fuzzer, Lookback distance should be a positive number, so it should be actually looked back rather than spinning. Fixes: 02827e1796b3 ("staging: erofs: add erofs_map_blocks_iter") Cc: # 4.19+ Signed-off-by: Gao Xiang --- drivers/staging/erofs/zmap.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/staging/erofs/zmap.c b/drivers/staging/erofs/zmap.c index 7408e86823a4..774dacbc5b32 100644 --- a/drivers/staging/erofs/zmap.c +++ b/drivers/staging/erofs/zmap.c @@ -350,6 +350,12 @@ static int vle_extent_lookback(struct z_erofs_maprecorder *m, switch (m->type) { case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD: + if (unlikely(!m->delta[0])) { + errln("invalid lookback distance 0 at nid %llu", + vi->nid); + DBG_BUGON(1); + return -EFSCORRUPTED; + } return vle_extent_lookback(m, m->delta[0]); case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN: map->m_flags &= ~EROFS_MAP_ZIPPED; -- 2.17.1