Horton

Re: Make query cancellation keys longer

Bruce Momjian <bruce@momjian.us>

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From: Bruce Momjian <bruce@momjian.us>
To: Peter Eisentraut <peter@eisentraut.org>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2024-03-06T01:12:18Z
Lists: pgsql-hackers 
On Fri, Mar  1, 2024 at 03:19:23PM +0100, Peter Eisentraut wrote:
> On 29.02.24 22:25, Heikki Linnakangas wrote:
> > Currently, cancel request key is a 32-bit token, which isn't very much
> > entropy. If you want to cancel another session's query, you can
> > brute-force it. In most environments, an unauthorized cancellation of a
> > query isn't very serious, but it nevertheless would be nice to have more
> > protection from it. The attached patch makes it longer. It is an
> > optional protocol feature, so it's fully backwards-compatible with
> > clients that don't support longer keys.
> 
> My intuition would be to make this a protocol version bump, not an optional
> feature.  I think this is something that everyone should eventually be
> using, not a niche feature that you explicitly want to opt-in for.

Agreed.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Only you can decide what is important to you.

Commits

  1. Add timingsafe_bcmp(), for constant-time memory comparison

  2. Add missing declarations to pg_config.h.in

  3. docs: Add a new section and a table listing protocol versions

  4. Make cancel request keys longer

  5. libpq: Add min/max_protocol_version connection options

  6. libpq: Handle NegotiateProtocolVersion message differently

  7. docs: Update phrase on message lengths in the protocol

  8. libpq: Trace all NegotiateProtocolVersion fields

  9. libpq: Add PQfullProtocolVersion to exports.txt

  10. Move cancel key generation to after forking the backend