Re: [HACKERS] Query cancel and OOB data

"Maurice Gittens" <mgittens@gits.nl> writes:
> Assuming that every user has a password which is known by both the client
> and the server, it seem to me like using a one-way function based on the
> clientuser password as the secret key (refered to above) is appropiate.
> This avoids the need for introducing "yet another shared secret into the
> system".

Well, I think that the cancel security mechanism ought to be per backend
process, not per user.  That is, simply being the same "Postgres user"
should not give you the ability to issue a cancel; you ought to be
required to have some direct association with a particular client/backend
session.  Access to the client/backend connection channel is one way;
knowledge of a per-connection secret is another.

Also, isn't it true that not all the supported authentication mechanisms
use a password?  Taking this approach would mean we have to design a new
cancel security mechanism for each authentication protocol.

            regards, tom lane