From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20111102221452.753088329@clark.kroah.org> Date: Wed, 02 Nov 2011 15:13:55 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Jeff Layton , Steve French Subject: [029/107] cifs: fix possible memory corruption in CIFSFindNext In-Reply-To: <20111102221600.GA26650@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 2.6.32-longterm review patch. If anyone has any objections, please let us know. ------------------ From: Jeff Layton 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 file changed, 2 insertions(+), 1 deletion(-) --- a/fs/cifs/cifssmb.c +++ b/fs/cifs/cifssmb.c @@ -3596,7 +3596,8 @@ int CIFSFindNext(const int xid, struct c 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"));