On 08/23/2011 04:51 PM, Jeff Layton wrote: > 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: <[email protected]> > Reported-by: Darren Lavender <[email protected]> > Signed-off-by: Jeff Layton <[email protected]> > --- > fs/cifs/cifssmb.c | 3 ++- > 1 files changed, 2 insertions(+), 1 deletions(-) > > diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c > index f4d0988..950464d 100644 > --- a/fs/cifs/cifssmb.c > +++ b/fs/cifs/cifssmb.c > @@ -4089,7 +4089,8 @@ int CIFSFindNext(const int xid, struct cifs_tcon *tcon, > T2_FNEXT_RSP_PARMS *parms; > char *response_data; > int rc = 0; > - int bytes_returned, name_len; > + int bytes_returned; > + unsigned int name_len;
Looks obviously correct. Just curious when does the server sends a very large resume_name_len? Does it try to overload with some other info in such circumstances? -- Suresh Jayaraman -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
