From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:56048 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727260AbeJICFv (ORCPT ); Mon, 8 Oct 2018 22:05:51 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dr Silvio Cesare of InfoSect , Dan Carpenter , Steve French , Aurelien Aptel , Sasha Levin Subject: [PATCH 4.18 138/168] cifs: read overflow in is_valid_oplock_break() Date: Mon, 8 Oct 2018 20:31:58 +0200 Message-Id: <20181008175625.283934273@linuxfoundation.org> In-Reply-To: <20181008175620.043587728@linuxfoundation.org> References: <20181008175620.043587728@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dan Carpenter [ Upstream commit 097f5863b1a0c9901f180bbd56ae7d630655faaa ] We need to verify that the "data_offset" is within bounds. Reported-by: Dr Silvio Cesare of InfoSect Signed-off-by: Dan Carpenter Signed-off-by: Steve French Reviewed-by: Aurelien Aptel Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/cifs/misc.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/fs/cifs/misc.c +++ b/fs/cifs/misc.c @@ -404,9 +404,17 @@ is_valid_oplock_break(char *buffer, stru (struct smb_com_transaction_change_notify_rsp *)buf; struct file_notify_information *pnotify; __u32 data_offset = 0; + size_t len = srv->total_read - sizeof(pSMBr->hdr.smb_buf_length); + if (get_bcc(buf) > sizeof(struct file_notify_information)) { data_offset = le32_to_cpu(pSMBr->DataOffset); + if (data_offset > + len - sizeof(struct file_notify_information)) { + cifs_dbg(FYI, "invalid data_offset %u\n", + data_offset); + return true; + } pnotify = (struct file_notify_information *) ((char *)&pSMBr->hdr.Protocol + data_offset); cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",