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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 3BF99C43381 for ; Wed, 27 Feb 2019 05:35:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0E020218E0 for ; Wed, 27 Feb 2019 05:35:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726933AbfB0Ffh (ORCPT ); Wed, 27 Feb 2019 00:35:37 -0500 Received: from szxga04-in.huawei.com ([45.249.212.190]:4172 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725903AbfB0Ffh (ORCPT ); Wed, 27 Feb 2019 00:35:37 -0500 Received: from DGGEMS401-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 710C026722DB91B90D98; Wed, 27 Feb 2019 13:35:34 +0800 (CST) Received: from 138.huawei.com (10.175.124.28) by smtp.huawei.com (10.3.19.201) with Microsoft SMTP Server (TLS) id 14.3.408.0; Wed, 27 Feb 2019 13:35:26 +0800 From: Gao Xiang To: Chao Yu , Greg Kroah-Hartman , CC: LKML , , "Chao Yu" , Miao Xie , , Fang Wei , Gao Xiang , Subject: [PATCH 1/3] staging: erofs: compressed_pages should not be accessed again after freed Date: Wed, 27 Feb 2019 13:33:30 +0800 Message-ID: <20190227053332.38504-1-gaoxiang25@huawei.com> X-Mailer: git-send-email 2.14.5 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.175.124.28] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch resolves the following page use-after-free issue, z_erofs_vle_unzip: ... for (i = 0; i < nr_pages; ++i) { ... z_erofs_onlinepage_endio(page); (1) } for (i = 0; i < clusterpages; ++i) { page = compressed_pages[i]; if (page->mapping == mngda) (2) continue; /* recycle all individual staging pages */ (void)z_erofs_gather_if_stagingpage(page_pool, page); (3) WRITE_ONCE(compressed_pages[i], NULL); } ... After (1) is executed, page is freed and could be then reused, if compressed_pages is scanned after that, it could fall info (2) or (3) by mistake and that could finally be in a mess. This patch aims to solve the above issue only with little changes as much as possible in order to make the fix backport easier. Fixes: 3883a79abd02 ("staging: erofs: introduce VLE decompression support") Cc: # 4.19+ Signed-off-by: Gao Xiang --- drivers/staging/erofs/unzip_vle.c | 38 ++++++++++++++++++----------------- drivers/staging/erofs/unzip_vle.h | 3 +-- drivers/staging/erofs/unzip_vle_lz4.c | 19 ++++++++---------- 3 files changed, 29 insertions(+), 31 deletions(-) diff --git a/drivers/staging/erofs/unzip_vle.c b/drivers/staging/erofs/unzip_vle.c index a127d8db76d8..416dde4e8ea1 100644 --- a/drivers/staging/erofs/unzip_vle.c +++ b/drivers/staging/erofs/unzip_vle.c @@ -986,11 +986,10 @@ static int z_erofs_vle_unzip(struct super_block *sb, if (llen > grp->llen) llen = grp->llen; - err = z_erofs_vle_unzip_fast_percpu(compressed_pages, - clusterpages, pages, llen, work->pageofs, - z_erofs_onlinepage_endio); + err = z_erofs_vle_unzip_fast_percpu(compressed_pages, clusterpages, + pages, llen, work->pageofs); if (err != -ENOTSUPP) - goto out_percpu; + goto out; if (sparsemem_pages >= nr_pages) goto skip_allocpage; @@ -1011,8 +1010,25 @@ static int z_erofs_vle_unzip(struct super_block *sb, erofs_vunmap(vout, nr_pages); out: + /* must handle all compressed pages before endding pages */ + for (i = 0; i < clusterpages; ++i) { + page = compressed_pages[i]; + +#ifdef EROFS_FS_HAS_MANAGED_CACHE + if (page->mapping == MNGD_MAPPING(sbi)) + continue; +#endif + /* recycle all individual staging pages */ + (void)z_erofs_gather_if_stagingpage(page_pool, page); + + WRITE_ONCE(compressed_pages[i], NULL); + } + for (i = 0; i < nr_pages; ++i) { page = pages[i]; + if (!page) + continue; + DBG_BUGON(!page->mapping); /* recycle all individual staging pages */ @@ -1025,20 +1041,6 @@ static int z_erofs_vle_unzip(struct super_block *sb, z_erofs_onlinepage_endio(page); } -out_percpu: - for (i = 0; i < clusterpages; ++i) { - page = compressed_pages[i]; - -#ifdef EROFS_FS_HAS_MANAGED_CACHE - if (page->mapping == MNGD_MAPPING(sbi)) - continue; -#endif - /* recycle all individual staging pages */ - (void)z_erofs_gather_if_stagingpage(page_pool, page); - - WRITE_ONCE(compressed_pages[i], NULL); - } - if (pages == z_pagemap_global) mutex_unlock(&z_pagemap_global_lock); else if (unlikely(pages != pages_onstack)) diff --git a/drivers/staging/erofs/unzip_vle.h b/drivers/staging/erofs/unzip_vle.h index 9dafa8dc712c..517e5ce8c5e9 100644 --- a/drivers/staging/erofs/unzip_vle.h +++ b/drivers/staging/erofs/unzip_vle.h @@ -218,8 +218,7 @@ int z_erofs_vle_plain_copy(struct page **compressed_pages, int z_erofs_vle_unzip_fast_percpu(struct page **compressed_pages, unsigned int clusterpages, struct page **pages, unsigned int outlen, - unsigned short pageofs, - void (*endio)(struct page *)); + unsigned short pageofs); int z_erofs_vle_unzip_vmap(struct page **compressed_pages, unsigned int clusterpages, void *vaddr, unsigned int llen, diff --git a/drivers/staging/erofs/unzip_vle_lz4.c b/drivers/staging/erofs/unzip_vle_lz4.c index 8e8d705a6861..48b263a2731a 100644 --- a/drivers/staging/erofs/unzip_vle_lz4.c +++ b/drivers/staging/erofs/unzip_vle_lz4.c @@ -125,8 +125,7 @@ int z_erofs_vle_unzip_fast_percpu(struct page **compressed_pages, unsigned int clusterpages, struct page **pages, unsigned int outlen, - unsigned short pageofs, - void (*endio)(struct page *)) + unsigned short pageofs) { void *vin, *vout; unsigned int nr_pages, i, j; @@ -148,19 +147,16 @@ int z_erofs_vle_unzip_fast_percpu(struct page **compressed_pages, ret = z_erofs_unzip_lz4(vin, vout + pageofs, clusterpages * PAGE_SIZE, outlen); - if (ret >= 0) { - outlen = ret; - ret = 0; - } + if (ret < 0) + goto out; + ret = 0; for (i = 0; i < nr_pages; ++i) { j = min((unsigned int)PAGE_SIZE - pageofs, outlen); if (pages[i]) { - if (ret < 0) { - SetPageError(pages[i]); - } else if (clusterpages == 1 && - pages[i] == compressed_pages[0]) { + if (clusterpages == 1 && + pages[i] == compressed_pages[0]) { memcpy(vin + pageofs, vout + pageofs, j); } else { void *dst = kmap_atomic(pages[i]); @@ -168,12 +164,13 @@ int z_erofs_vle_unzip_fast_percpu(struct page **compressed_pages, memcpy(dst + pageofs, vout + pageofs, j); kunmap_atomic(dst); } - endio(pages[i]); } vout += PAGE_SIZE; outlen -= j; pageofs = 0; } + +out: preempt_enable(); if (clusterpages == 1) -- 2.14.5