Re: Invalidate the subscription worker in cases where a user loses their superuser status

Amit Kapila <amit.kapila16@gmail.com>

From: Amit Kapila <amit.kapila16@gmail.com>
To: vignesh C <vignesh21@gmail.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2023-09-23T05:58:04Z
Lists: pgsql-hackers
On Sat, Sep 23, 2023 at 1:27 AM vignesh C <vignesh21@gmail.com> wrote:
>
>
> Fixed this issue by checking if the subscription owner has changed
> from superuser to non-superuser in case the pg_authid rows changes.
> The attached patch has the changes for the same.
>

@@ -3952,7 +3953,9 @@ maybe_reread_subscription(void)
  newsub->passwordrequired != MySubscription->passwordrequired ||
  strcmp(newsub->origin, MySubscription->origin) != 0 ||
  newsub->owner != MySubscription->owner ||
- !equal(newsub->publications, MySubscription->publications))
+ !equal(newsub->publications, MySubscription->publications) ||
+ (!superuser_arg(MySubscription->owner) &&
+ MySubscription->isownersuperuser))
  {
  if (am_parallel_apply_worker())
  ereport(LOG,
@@ -4605,6 +4608,13 @@ InitializeLogRepWorker(void)
  proc_exit(0);
  }

+ /*
+ * Fetch subscription owner is a superuser. This value will be later
+ * checked to see when there is any change with this role and the worker
+ * will be restarted if required.
+ */
+ MySubscription->isownersuperuser = superuser_arg(MySubscription->owner);

Why didn't you filled this parameter in GetSubscription() like other
parameters? If we do that then the comparison of first change in your
patch will look similar to all other comparisons.

-- 
With Regards,
Amit Kapila.



Commits

  1. Restart the apply worker if the privileges have been revoked.