Re: Replay attack of query cancel

This bug has not been fixed, but it is on the TODO list:
o Prevent query cancel packets from being replayed by an attacker,especially when using SSL 

I am going to consider this item closed meaning I am not going to track
that it is fixed for 8.4;  it is just documented on our TODO as a known
limitation.

---------------------------------------------------------------------------

Magnus Hagander wrote:
> Tom Lane wrote:
> > Alvaro Herrera <alvherre@commandprompt.com> writes:
> >> Andrew Gierth wrote:
> >>> 2. The server accepts either the old-style or the secure cancel
> >>> request from the client, but doesn't allow old-style requests
> >>> once a valid secure request has been seen.
> > 
> >> Hmm, I think there should be a way to turn off acceptance of old-style
> >> without necessarily requiring a new-style request.  Otherwise, how are
> >> you protected from DoS if you have never sent a cancel request at all?
> > 
> > Assuming you were using SSL, it's hard to see how an attacker is going
> > to get your cancel key without having seen a cancel request.
> 
> Not only that, but he'll have to see an *old-style* cancel request,
> since the new style doesn't contain the key.
> 
> And if you're *not* using SSL, the attacker can just sniff they key off
> the initial packet instead.
> 
> 
> > However, I dislike Andrew's proposal above even without that issue,
> > because it means *still more* changeable state that has to be magically
> > shared between postmaster and backends.  If we want to have a way for
> > people to disable insecure cancels, we should just have a postmaster
> > configuration parameter that does it.
> 
> Agreed. Your security policy also should not depend on what your client
> happens to do, it should be enforceable.
> 
> 
> //Magnus
> 
> 
> -- 
> Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
> To make changes to your subscription:
> http://www.postgresql.org/mailpref/pgsql-hackers

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + If your life is a hard drive, Christ can be your backup. +