From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:58726 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728702AbeIXSkZ (ORCPT ); Mon, 24 Sep 2018 14:40:25 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dan Carpenter , Steve French , Aurelien Aptel Subject: [PATCH 4.18 136/235] cifs: integer overflow in in SMB2_ioctl() Date: Mon, 24 Sep 2018 13:52:02 +0200 Message-Id: <20180924113119.368977469@linuxfoundation.org> In-Reply-To: <20180924113103.999624566@linuxfoundation.org> References: <20180924113103.999624566@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 commit 2d204ee9d671327915260071c19350d84344e096 upstream. The "le32_to_cpu(rsp->OutputOffset) + *plen" addition can overflow and wrap around to a smaller value which looks like it would lead to an information leak. Fixes: 4a72dafa19ba ("SMB2 FSCTL and IOCTL worker function") Signed-off-by: Dan Carpenter Signed-off-by: Steve French Reviewed-by: Aurelien Aptel CC: Stable Signed-off-by: Greg Kroah-Hartman --- fs/cifs/smb2pdu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -2418,14 +2418,14 @@ SMB2_ioctl(const unsigned int xid, struc /* We check for obvious errors in the output buffer length and offset */ if (*plen == 0) goto ioctl_exit; /* server returned no data */ - else if (*plen > 0xFF00) { + else if (*plen > rsp_iov.iov_len || *plen > 0xFF00) { cifs_dbg(VFS, "srv returned invalid ioctl length: %d\n", *plen); *plen = 0; rc = -EIO; goto ioctl_exit; } - if (rsp_iov.iov_len < le32_to_cpu(rsp->OutputOffset) + *plen) { + if (rsp_iov.iov_len - *plen < le32_to_cpu(rsp->OutputOffset)) { cifs_dbg(VFS, "Malformed ioctl resp: len %d offset %d\n", *plen, le32_to_cpu(rsp->OutputOffset)); *plen = 0;