bitmaps in srv_lsa_hnd.c

[Gerald Carter]

Tim Potter wrote:
> 
> Gerald Carter writes:
> 
> > The only purpose of bmap that I see is to prevent us
> > from allocating more than MAX_OPEN_POLS at any given time
> > for an smbd.  If I were to guess, this to prevent a DoS
> > attack where a client exhausts the server by opening
> > LSA policy handles and never closing them?
> 
> You'll still get a DoS attack of sorts, as opening 64 handles
> without closing them would prevent other people from opening more
> handles for legitmate purposes.

But only on a single smbd which is associated with 
a single user/client.  Opening a new policy handle involves
a malloc so if there was not an upper bound on this, you 
could theoretically crater the server by causing an smbd 
process to suck up all the available RAM.

> A better idea would be to start discarding open handles 
> on a LRU basis so that a request for a new  handle 
> always succeeds.

Ummm....I'm not sure about this one.  Do you feel 
good about the side effects?






jerry
----------------------------------------------------------------------
   /\  Gerald (Jerry) Carter                     Professional Services
 \/    http://www.valinux.com  VA Linux Systems    gcarter at valinux.com
       http://www.samba.org       SAMBA Team           jerry at samba.org
       http://www.eng.auburn.edu/~cartegw

       "...a hundred billion castaways looking for a home."
                                - Sting "Message in a Bottle" ( 1979 )