From: Jeff Layton Date: Tue, 13 Sep 2011 13:24:02 +0000 (+0100) Subject: cifs: fix possible memory corruption in CIFSFindNext, CVE-2011-3191 X-Git-Url: http://git.alex.org.uk cifs: fix possible memory corruption in CIFSFindNext, CVE-2011-3191 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. Cc: Reported-by: Darren Lavender Signed-off-by: Jeff Layton Signed-off-by: Steve French Signed-off-by: Suresh Jayaraman (cherry-picked from commit c32dfffaf59f73bbcf4472141b851a4dc5db2bf0 cifs-2.6.git) CVE-2011-3191 BugLink: http://bugs.launchpad.net/bugs/834135 Signed-off-by: Andy Whitcroft Signed-off-by: Tim Gardner --- diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c index 904aa47..e9abcf9 100644 --- a/fs/cifs/cifssmb.c +++ b/fs/cifs/cifssmb.c @@ -3805,7 +3805,8 @@ int CIFSFindNext(const int xid, struct cifsTconInfo *tcon, 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");