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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E76DAC6FA86 for ; Wed, 14 Sep 2022 09:57:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230287AbiINJ5h (ORCPT ); Wed, 14 Sep 2022 05:57:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37966 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231487AbiINJ5Y (ORCPT ); Wed, 14 Sep 2022 05:57:24 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4277F6A48B; Wed, 14 Sep 2022 02:57:19 -0700 (PDT) Received: from canpemm500010.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4MSFzw1dRkznVCd; Wed, 14 Sep 2022 17:54:36 +0800 (CST) Received: from huawei.com (10.175.127.227) by canpemm500010.china.huawei.com (7.192.105.118) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Wed, 14 Sep 2022 17:57:17 +0800 From: Ye Bin To: , , CC: , , Ye Bin Subject: [PATCH -next 2/2] jbd2: fix potential use-after-free in jbd2_fc_wait_bufs Date: Wed, 14 Sep 2022 18:08:12 +0800 Message-ID: <20220914100812.1414768-3-yebin10@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20220914100812.1414768-1-yebin10@huawei.com> References: <20220914100812.1414768-1-yebin10@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To canpemm500010.china.huawei.com (7.192.105.118) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org In 'jbd2_fc_wait_bufs' use 'bh' after put buffer head reference count which may lead to use-after-free. So judge buffer if uptodate before put buffer head reference count. Signed-off-by: Ye Bin --- fs/jbd2/journal.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c index 1c833d8cb0fe..4d49f629d06b 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -923,16 +923,16 @@ int jbd2_fc_wait_bufs(journal_t *journal, int num_blks) for (i = j_fc_off - 1; i >= j_fc_off - num_blks; i--) { bh = journal->j_fc_wbuf[i]; wait_on_buffer(bh); - put_bh(bh); - journal->j_fc_wbuf[i] = NULL; /* * Update j_fc_off so jbd2_fc_release_bufs can release remain * buffer head. */ if (unlikely(!buffer_uptodate(bh))) { - journal->j_fc_off = i; + journal->j_fc_off = i + 1; return -EIO; } + put_bh(bh); + journal->j_fc_wbuf[i] = NULL; } return 0; -- 2.31.1