From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dan Carpenter Subject: [PATCH 4.4 30/43] staging: ncpfs: memory corruption in ncp_read_kernel() Date: Tue, 27 Mar 2018 18:27:34 +0200 Message-Id: <20180327162718.108104061@linuxfoundation.org> In-Reply-To: <20180327162716.407986916@linuxfoundation.org> References: <20180327162716.407986916@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.4-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 @@ -980,6 +980,10 @@ 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);