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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 643F5C4332B for ; Sat, 21 Mar 2020 12:22:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 37AA120724 for ; Sat, 21 Mar 2020 12:22:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584793345; bh=/3nPfZXBKwKIY++A+xEYIPUcMBEvmjAt1f4xiG8QQQU=; h=From:To:Cc:Subject:Date:List-ID:From; b=yOTpYtVbBzQc9beyPAgSs0A7mf6pIO7PUOKdeDdkHgkxjDHx8Fr48UuuQCW1VbqKs 39HzjdYA/OeDXAoOPara+PsxS84SkdR1X+bIYzO26/rWRQ0ApfFvWlkDub4eDmTZAC Z3YQ83kn/IagIw/aQ+l+Bkbo476A6qkoFA3klj7Q= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727145AbgCUMWY (ORCPT ); Sat, 21 Mar 2020 08:22:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:56418 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726192AbgCUMWX (ORCPT ); Sat, 21 Mar 2020 08:22:23 -0400 Received: from localhost.localdomain (unknown [49.65.245.234]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D83F720722; Sat, 21 Mar 2020 12:22:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584793343; bh=/3nPfZXBKwKIY++A+xEYIPUcMBEvmjAt1f4xiG8QQQU=; h=From:To:Cc:Subject:Date:From; b=JFmljKSM8w9/MneocFtCjszq19tzQLUtntTjEkg7r6wBDNMD7T8A1AbIhFWOu1Wpn yRFtKKuUiHqvhVhVePJR3SwyRBbZNEBzcJAiT4PkEBPC5aevrhdPPOm7Y/Uk/6+Uzn Z9HwnHUPCi+NZeILt1EwiwSm9T+SMUoFLuJpmesw= From: Chao Yu To: jaegeuk@kernel.org Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Chao Yu Subject: [PATCH v2 3/4] f2fs: fix NULL pointer dereference in f2fs_verity_work() Date: Sat, 21 Mar 2020 20:21:53 +0800 Message-Id: <20200321122153.22424-1-chao@kernel.org> X-Mailer: git-send-email 2.22.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Chao Yu If both compression and fsverity feature is on, generic/572 will report below NULL pointer dereference bug. BUG: kernel NULL pointer dereference, address: 0000000000000018 RIP: 0010:f2fs_verity_work+0x60/0x90 [f2fs] #PF: supervisor read access in kernel mode Workqueue: fsverity_read_queue f2fs_verity_work [f2fs] RIP: 0010:f2fs_verity_work+0x60/0x90 [f2fs] Call Trace: process_one_work+0x16c/0x3f0 worker_thread+0x4c/0x440 ? rescuer_thread+0x350/0x350 kthread+0xf8/0x130 ? kthread_unpark+0x70/0x70 ret_from_fork+0x35/0x40 There are two issue in f2fs_verity_work(): - it needs to traverse and verify all pages in bio. - if pages in bio belong to non-compressed cluster, accessing decompress IO context stored in page private will cause NULL pointer dereference. Fix them. Signed-off-by: Chao Yu --- v2: - fix error path of f2fs_verify_bio pointed out by Eric fs/f2fs/data.c | 37 ++++++++++++++++++++++++++++++++----- 1 file changed, 32 insertions(+), 5 deletions(-) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 5c5db09324b7..d5b1eda21519 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -187,12 +187,39 @@ static void f2fs_verify_pages(struct page **rpages, unsigned int cluster_size) static void f2fs_verify_bio(struct bio *bio) { - struct page *page = bio_first_page_all(bio); - struct decompress_io_ctx *dic = - (struct decompress_io_ctx *)page_private(page); + struct bio_vec *bv; + struct bvec_iter_all iter_all; + struct decompress_io_ctx *dic, *pdic = NULL; + + bio_for_each_segment_all(bv, bio, iter_all) { + struct page *page = bv->bv_page; + + dic = (struct decompress_io_ctx *)page_private(page); - f2fs_verify_pages(dic->rpages, dic->cluster_size); - f2fs_free_dic(dic); + if (dic) { + if (dic != pdic) { + f2fs_verify_pages(dic->rpages, + dic->cluster_size); + f2fs_free_dic(dic); + pdic = dic; + } + continue; + } + pdic = dic; + + if (bio->bi_status || PageError(page)) + goto clear_uptodate; + + if (fsverity_verify_page(page)) { + SetPageUptodate(page); + goto unlock; + } +clear_uptodate: + ClearPageUptodate(page); + ClearPageError(page); +unlock: + unlock_page(page); + } } #endif -- 2.22.0