From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:49184 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932739AbeC0Qmh (ORCPT ); Tue, 27 Mar 2018 12:42:37 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dan Carpenter Subject: [PATCH 4.15 074/105] staging: ncpfs: memory corruption in ncp_read_kernel() Date: Tue, 27 Mar 2018 18:27:54 +0200 Message-Id: <20180327162802.508474143@linuxfoundation.org> In-Reply-To: <20180327162757.813009222@linuxfoundation.org> References: <20180327162757.813009222@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dan Carpenter commit 4c41aa24baa4ed338241d05494f2c595c885af8f upstream. If the server is malicious then *bytes_read could be larger than the size of the "target" buffer. It would lead to memory corruption when we do the memcpy(). Reported-by: Dr Silvio Cesare of InfoSect Signed-off-by: Dan Carpenter Cc: stable Signed-off-by: Greg Kroah-Hartman --- fs/ncpfs/ncplib_kernel.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/fs/ncpfs/ncplib_kernel.c +++ b/fs/ncpfs/ncplib_kernel.c @@ -981,6 +981,10 @@ ncp_read_kernel(struct ncp_server *serve goto out; } *bytes_read = ncp_reply_be16(server, 0); + if (*bytes_read > to_read) { + result = -EINVAL; + goto out; + } source = ncp_reply_data(server, 2 + (offset & 1)); memcpy(target, source, *bytes_read);