PostgreSQL security updates

[Christoph Berg <myon@debian.org>]

Hi,

I just uploaded 3 PostgreSQL security updates:

postgresql-15_15.5-0+deb12u1_source.changes
postgresql-13_13.13-0+deb11u1_source.changes
postgresql-11_11.22-0+deb10u1_source.changes

Unstable has been fixed in 16.1-1. (I don't intend to fix PG15 in
unstable, the package will be removed soon.)

The set of CVEs is the same in all:

    * Fix handling of unknown-type arguments in DISTINCT "any" aggregate
      functions (Tom Lane)

      This error led to a text-type value being interpreted as an unknown-type
      value (that is, a zero-terminated string) at runtime.  This could result
      in disclosure of server memory following the text value.

      The PostgreSQL Project thanks Jingzhou Fu for reporting this problem.
      (CVE-2023-5868)

    * Detect integer overflow while computing new array dimensions
      (Tom Lane)

      When assigning new elements to array subscripts that are outside the
      current array bounds, an undetected integer overflow could occur in edge
      cases.  Memory stomps that are potentially exploitable for arbitrary
      code execution are possible, and so is disclosure of server memory.

      The PostgreSQL Project thanks Pedro Gallegos for reporting this problem.
      (CVE-2023-5869)

    * Prevent the pg_signal_backend role from signalling background workers
      and autovacuum processes (Noah Misch, Jelte Fennema-Nio)

      The documentation says that pg_signal_backend
      cannot issue signals to superuser-owned processes.  It was able to
      signal these background processes, though, because they advertise a
      role OID of zero.  Treat that as indicating superuser ownership.
      The security implications of cancelling one of these process types
      are fairly small so far as the core code goes (we'll just start
      another one), but extensions might add background workers that are
      more vulnerable.

      Also ensure that the is_superuser parameter is set correctly in such
      processes.  No specific security consequences are known for that
      oversight, but it might be significant for some extensions.

      The PostgreSQL Project thanks Hemanth Sandrana and Mahendrakar
      Srinivasarao for reporting this problem. (CVE-2023-5870)

Furthermore, 11.22 is the last release in the 11 branch, so there will
be no more updates for that one:

    * This is expected to be the last PostgreSQL release in the 11.X series.
      Users are encouraged to update to a newer release branch soon.

13 and 15 also fix index corruptions, I put a selection into the
changelogs:

    * Fix misbehavior during recursive page split in GiST index build
      (Heikki Linnakangas)

      Fix a case where the location of a page downlink was incorrectly
      tracked, and introduce some logic to allow recovering from such
      situations rather than silently doing the wrong thing.  This error could
      result in incorrect answers from subsequent index searches. It may be
      advisable to reindex all GiST indexes after installing this update.

    * Prevent de-duplication of btree index entries for interval columns

      There are interval values that are distinguishable but compare equal,
      for example 24:00:00 and 1 day.  This breaks assumptions made by btree
      de-duplication, so interval columns need to be excluded from
      de-duplication.  This oversight can cause incorrect results from
      index-only scans.  Moreover, after updating amcheck will report an error
      for almost all such indexes.  Users should reindex any btree indexes on
      interval columns.

Please consider handling/announcing these whenever there's time.

Thanks,
Christoph