From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20120205220951.247956479@pcw.home.local> Date: Sun, 05 Feb 2012 23:10:31 +0100 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jeff Layton , Steve French , Greg KH Subject: [PATCH 42/91] cifs: fix possible memory corruption in CIFSFindNext In-Reply-To: <0635750f5f06ed2ca212b91fcb5c4483@local> Sender: linux-kernel-owner@vger.kernel.org List-ID: 2.6.27-longterm review patch. If anyone has any objections, please let us know. ------------------ commit 9438fabb73eb48055b58b89fc51e0bc4db22fabd upstream. The name_len variable in CIFSFindNext is a signed int that gets set to the resume_name_len in the cifs_search_info. The resume_name_len however is unsigned and for some infolevels is populated directly from a 32 bit value sent by the server. If the server sends a very large value for this, then that value could look negative when converted to a signed int. That would make that value pass the PATH_MAX check later in CIFSFindNext. The name_len would then be used as a length value for a memcpy. It would then be treated as unsigned again, and the memcpy scribbles over a ton of memory. Fix this by making the name_len an unsigned value in CIFSFindNext. Reported-by: Darren Lavender Signed-off-by: Jeff Layton Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman --- fs/cifs/cifssmb.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) Index: longterm-2.6.27/fs/cifs/cifssmb.c =================================================================== --- longterm-2.6.27.orig/fs/cifs/cifssmb.c 2012-02-05 22:34:33.755917316 +0100 +++ longterm-2.6.27/fs/cifs/cifssmb.c 2012-02-05 22:34:40.813915010 +0100 @@ -3649,7 +3649,8 @@ T2_FNEXT_RSP_PARMS *parms; char *response_data; int rc = 0; - int bytes_returned, name_len; + int bytes_returned; + unsigned int name_len; __u16 params, byte_count; cFYI(1, ("In FindNext"));