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=-20.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,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 B3C31C433EF for ; Mon, 20 Sep 2021 17:11:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9A64D61BD4 for ; Mon, 20 Sep 2021 17:11:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345983AbhITRNR (ORCPT ); Mon, 20 Sep 2021 13:13:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:33902 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343489AbhITRLH (ORCPT ); Mon, 20 Sep 2021 13:11:07 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 44C83613A3; Mon, 20 Sep 2021 16:56:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1632157015; bh=t9tEat3ZVKAChYi9xcQ3UhIPOgPUidcS1OFDZJhmYrw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=f8br9jw3hSpmfKsFMdNKBW13d7s5NeSlQErUvTfMqYVLhALCzjYYgSqB1y6Ho7msw XJlxbmXOlQbD6yW3sZv+tun7m0Fud2cmB/MqtpBHKWeG3+DIX12hhhgoFV4qTRAD5e okRfrSJ9JqOprpGt/aOamCOSy4O5Lif3DkeIJ/zM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Chao Yu , Jaegeuk Kim Subject: [PATCH 4.14 015/217] f2fs: fix potential overflow Date: Mon, 20 Sep 2021 18:40:36 +0200 Message-Id: <20210920163925.129646852@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210920163924.591371269@linuxfoundation.org> References: <20210920163924.591371269@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Chao Yu commit a9af3fdcc4258af406879eca63d82e9d6baa892e upstream. In build_sit_entries(), if valid_blocks in SIT block is smaller than valid_blocks in journal, for below calculation: sbi->discard_blks += old_valid_blocks - se->valid_blocks; There will be two times potential overflow: - old_valid_blocks - se->valid_blocks will overflow, and be a very large number. - sbi->discard_blks += result will overflow again, comes out a correct result accidently. Anyway, it should be fixed. Fixes: d600af236da5 ("f2fs: avoid unneeded loop in build_sit_entries") Fixes: 1f43e2ad7bff ("f2fs: introduce CP_TRIMMED_FLAG to avoid unneeded discard") Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Greg Kroah-Hartman --- fs/f2fs/segment.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -3337,14 +3337,17 @@ static int build_sit_entries(struct f2fs } else { memcpy(se->discard_map, se->cur_valid_map, SIT_VBLOCK_MAP_SIZE); - sbi->discard_blks += old_valid_blocks - - se->valid_blocks; + sbi->discard_blks += old_valid_blocks; + sbi->discard_blks -= se->valid_blocks; } } - if (sbi->segs_per_sec > 1) + if (sbi->segs_per_sec > 1) { get_sec_entry(sbi, start)->valid_blocks += - se->valid_blocks - old_valid_blocks; + se->valid_blocks; + get_sec_entry(sbi, start)->valid_blocks -= + old_valid_blocks; + } } up_read(&curseg->journal_rwsem);