Re: Two-phase commit security restrictions

Alvaro Herrera wrote:
>>>Another approach I've been thinking about is to allow anyone that knows
>>>the (user-supplied) global transaction identifier to finish the
>>>transaction, and hide the gids of running transactions from regular
>>>users. That way, the gid acts as a secret token that's only known by the
>>>transaction manager, much like the cancel key.
>>
>>Personally I prefer the last. It should be infeasible to crack as long
>>as the gid is long enough (e.g. sufficiently random 128bit value or
>>more) and the channel between the TM and Postgres is secure.
>
> So it is possible for a user connected to the DB to send random commit
> or cancel commands, just in case she happens to hit a valid GID?

It is not essentially different from someone trying to bruteforce a
password. A 128bit value like a random GUID is as strong as a 16 char
password comprising ASCII 0-255 characters. And I would argue that this
is _not_ security through obscurity. Security through obscurity is
relying on unpublished methods/algorithms. This is not.

But I understand that everybody seems to be against this idea.

--
dave