From: Jeff Layton Date: Tue, 23 Aug 2011 11:21:28 +0000 (-0400) Subject: cifs: fix possible memory corruption in CIFSFindNext X-Git-Tag: v2.6.27.60~52 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=de885f182add8990043f636a45490476d424c7f1;p=thirdparty%2Fkernel%2Fstable.git cifs: fix possible memory corruption in CIFSFindNext 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 Signed-off-by: Willy Tarreau --- diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c index 31a1668c1a091..b59e175fe6df0 100644 --- a/fs/cifs/cifssmb.c +++ b/fs/cifs/cifssmb.c @@ -3649,7 +3649,8 @@ 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"));