[ubuntu/lunar-security] postgresql-15 15.5-0ubuntu0.23.04.1 (Accepted)

[Marc Deslauriers]

postgresql-15 (15.5-0ubuntu0.23.04.1) lunar-security; urgency=medium

  * New upstream version (LP: #2040469).

    + A dump/restore is not required for those running 15.X.

    + However, several mistakes have been discovered that could lead to
      certain types of indexes yielding wrong search results or being
      unnecessarily inefficient. It is advisable to REINDEX
      potentially-affected indexes after installing this update.

    + Also, if you are upgrading from a version earlier than 15.4, see
      those release notes as well please.

    + 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.
      (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.
      (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.
      (CVE-2023-5870)

    + 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
      (Noah Misch)

      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.

    + Process date values more sanely in BRIN datetime_minmax_multi_ops
      indexes (Tomas Vondra)

      The distance calculation for dates was backward, causing poor decisions
      about which entries to merge. The index still produces correct results,
      but is much less efficient than it should be. Reindexing BRIN
      minmax_multi indexes on date columns is advisable.

    + Process large timestamp and timestamptz values more sanely in BRIN
      datetime_minmax_multi_ops indexes (Tomas Vondra)

      Infinities were mistakenly treated as having distance zero rather than a
      large distance from other values, causing poor decisions about which
      entries to merge. Also, finite-but-very-large values (near the endpoints
      of the representable timestamp range) could result in internal
      overflows, again causing poor decisions. The index still produces
      correct results, but is much less efficient than it should be.
      Reindexing BRIN minmax_multi indexes on timestamp and timestamptz
      columns is advisable if the column contains, or has contained,
      infinities or large finite values.

    + Details about these and many further changes can be found at:
      https://www.postgresql.org/docs/15/release-15-5.html.

  * d/p/libpgport-pkglibdir: adjust patch for new release.

Date: 2023-12-05 12:51:26.472686+00:00
Changed-By: Athos Ribeiro <athos.ribeiro at canonical.com>
Signed-By: Marc Deslauriers <marc.deslauriers at canonical.com>
https://launchpad.net/ubuntu/+source/postgresql-15/15.5-0ubuntu0.23.04.1
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