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=-12.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS autolearn=ham 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 0653BC43381 for ; Wed, 27 Feb 2019 14:43:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BFC652183F for ; Wed, 27 Feb 2019 14:43:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551278600; bh=VgPSZgYfzsAb0gTECkKcER04At2p4EGIiQqUjVBnLlo=; h=Subject:To:From:Date:List-ID:From; b=Q4+R4ar0acfcgSJJzsfKisQL5YF7PFCOBR6J6MAA1P9eX5qeJUv/xTEds9I8Ev4Os lALeRhRcDzyg8qYanhfru4JQt2blpApiQ7x4hziu8+DXU3EOB3u1whuGqXWBf4TH/g 15VWP7R7oHA9sFKxAjr3msWD8fUQQMMgpO5s+a80= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730520AbfB0OnU (ORCPT ); Wed, 27 Feb 2019 09:43:20 -0500 Received: from mail.kernel.org ([198.145.29.99]:52186 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725854AbfB0OnT (ORCPT ); Wed, 27 Feb 2019 09:43:19 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.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 E10ED217F5; Wed, 27 Feb 2019 14:43:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551278598; bh=VgPSZgYfzsAb0gTECkKcER04At2p4EGIiQqUjVBnLlo=; h=Subject:To:From:Date:From; b=ftuOGHCco1yLLke3xHrtewCudxy42xkUUrF/+VjGDkK9mq6pfy3Dn8667qEVWj7aK 3ACQaxEGL54NsI8WqIDRM8OFV134DGl7oX8LeF21Sef+JhYSaBV+0Zf7EB2VXpe9tF WbKbmtJzHOWE/UfAddGNpKFIipvI0u7/NPAptuJc= Subject: patch "staging: erofs: compressed_pages should not be accessed again after" added to staging-testing To: gaoxiang25@huawei.com, gregkh@linuxfoundation.org, stable@vger.kernel.org, yuchao0@huawei.com From: Date: Wed, 27 Feb 2019 15:43:14 +0100 Message-ID: <155127859451101@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org This is a note to let you know that I've just added the patch titled staging: erofs: compressed_pages should not be accessed again after to my staging git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git in the staging-testing branch. The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.) The patch will be merged to the staging-next branch sometime soon, after it passes testing, and the merge window is open. If you have any questions about this process, please let me know. >From af692e117cb8cd9d3d844d413095775abc1217f9 Mon Sep 17 00:00:00 2001 From: Gao Xiang Date: Wed, 27 Feb 2019 13:33:30 +0800 Subject: staging: erofs: compressed_pages should not be accessed again after freed 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 Reviewed-by: Chao Yu Signed-off-by: Greg Kroah-Hartman --- 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) -- 2.21.0