Release Notes

Prevent CREATE SCHEMA from defeating changes in search_path (Alexander Lakhin)

Within a CREATE SCHEMA command, objects in the prevailing search_path, as well as those in the newly-created schema, would be visible even within a called function or script that attempted to set a secure search_path. This could allow any user having permission to create a schema to hijack the privileges of a security definer function or extension script.

The PostgreSQL Project thanks Alexander Lakhin for reporting this problem. (CVE-2023-2454)

Enforce row-level security policies correctly after inlining a set-returning function (Stephen Frost, Tom Lane)

If a set-returning SQL-language function refers to a table having row-level security policies, and it can be inlined into a calling query, those RLS policies would not get enforced properly in some cases involving re-using a cached plan under a different role. This could allow a user to see or modify rows that should have been invisible.

The PostgreSQL Project thanks Wolfgang Walther for reporting this problem. (CVE-2023-2455)

Avoid crash when the new schema name is omitted in CREATE SCHEMA (Michael Paquier)

The SQL standard allows writing CREATE SCHEMA AUTHORIZATION owner_name, with the schema name defaulting to owner_name. However some code paths expected the schema name to be present and would fail.

Disallow altering composite types that are stored in indexes (Tom Lane)

ALTER TYPE disallows non-binary-compatible modifications of composite types if they are stored in any table columns. (Perhaps that will be allowed someday, but it hasn't happened yet; the locking implications of rewriting many tables are daunting.) We overlooked the possibility that an index might contain a composite type that doesn't also appear in its table.

Ensure that COPY TO from an RLS-enabled parent table does not copy any rows from child tables (Antonin Houska)

The documentation is quite clear that COPY TO copies rows from only the named table, not any inheritance children it may have. However, if row-level security was enabled on the table then this stopped being true.

Avoid possible crash when array_position() or array_positions() is passed an empty array (Tom Lane)

Fix possible out-of-bounds fetch in to_char() (Tom Lane)

With bad luck this could have resulted in a server crash.

Avoid buffer overread in translate() function (Daniil Anisimov)

When using the deletion feature, the function might fetch the byte just after the input string, creating a small risk of crash.

Fix error cursor setting for parse errors in JSON string literals (Tom Lane)

Most cases in which a syntax error is detected in a string literal within a JSON value failed to set the error cursor appropriately. This led at least to an unhelpful error message (pointing to the token before the string, rather than the actual trouble spot), and could even result in a crash in v14 and later.

Fix parser's failure to detect some cases of improperly-nested aggregates (Tom Lane)

This oversight could lead to executor failures for queries that should have been rejected as invalid.

Fix data structure corruption during parsing of serial SEQUENCE NAME options (David Rowley)

This can lead to trouble if an event trigger captures the corrupted parse tree.

Correctly update plan nodes' parallel-safety markings when moving initplans from one node to another (Tom Lane)

This planner oversight could lead to “subplan was not initialized” errors at runtime.

Disable the inverse-transition optimization for window aggregates when the call contains sub-SELECTs (David Rowley)

This optimization requires that the aggregate's argument expressions have repeatable results, which might not hold for a sub-SELECT.

Fix oversights in execution of nested ARRAY[] constructs (Alexander Lakhin, Tom Lane)

Correctly detect overflow of the total space needed for the result array, avoiding a possible crash due to undersized output allocation. Also ensure that any trailing padding space in the result array is zeroed; while leaving garbage there is harmless for most purposes, it can result in odd behavior later.

Fix partition pruning logic for partitioning on boolean columns (David Rowley)

Pruning with a condition like boolcol IS NOT TRUE was done incorrectly, leading to possibly not returning rows in which boolcol is NULL. Also, the rather unlikely case of partitioning on NOT boolcol was handled incorrectly.

Fix race condition in per-batch cleanup during parallel hash join (Thomas Munro, Melanie Plageman)

A crash was possible given unlucky timing and parallel_leader_participation = off (which is not the default).

Don't balance vacuum cost delay when a table has a per-relation vacuum_cost_delay setting of zero (Masahiko Sawada)

Delay balancing is supposed to be disabled whenever autovacuum is processing a table with a per-relation vacuum_cost_delay setting, but this was done only for positive settings, not zero.

Fix corner-case crashes when columns have been added to the end of a view (Tom Lane)

Repair rare failure of MULTIEXPR_SUBLINK subplans in partitioned updates (Andres Freund, Tom Lane)

Use of the syntax INSERT ... ON CONFLICT DO UPDATE SET (c1, ...) = (SELECT ...) with a partitioned target table could result in failure if any child table is dissimilar from the parent (for example, different physical column order). This typically manifested as failure of consistency checks in the executor; but a crash or incorrect data updates are also possible.

Fix handling of DEFAULT markers within a multi-row INSERT ... VALUES query on a view that has a DO ALSO INSERT ... SELECT rule (Dean Rasheed)

Such cases typically failed with “unrecognized node type” errors or assertion failures.

Support references to OLD and NEW within subqueries in rule actions (Dean Rasheed, Tom Lane)

Such references are really lateral references, but the server could crash if the subquery wasn't explicitly marked with LATERAL. Arrange to do that implicitly when necessary.

When decompiling a rule or SQL function body containing INSERT/UPDATE/DELETE within WITH, take care to print the correct alias for the target table (Tom Lane)

Fix glitches in SERIALIZABLE READ ONLY optimization (Thomas Munro)

Transactions already marked as “doomed” confused the safe-snapshot optimization for SERIALIZABLE READ ONLY transactions. The optimization was unnecessarily skipped in some cases. In other cases an assertion failure occurred (but there was no problem in non-assert builds).

Avoid leaking cache callback slots in the pgoutput logical decoding plugin (Shi Yu)

Multiple cycles of starting up and shutting down the plugin within a single session would eventually lead to an “out of relcache_callback_list slots” error.

Fix dereference of dangling pointer during buffering build of a GiST index (Alexander Lakhin)

This error seems to usually be harmless in production builds, as the fetched value is noncritical; but in principle it could cause a server crash.

Ignore dropped columns during logical replication of an update or delete action (Onder Kalaci, Shi Yu)

Replication with the REPLICA IDENTITY FULL option failed if the table contained such columns.

Support RSA-PSS certificates with SCRAM-SHA-256 channel binding (Jacob Champion, Heikki Linnakangas)

This feature requires building with OpenSSL 1.1.1 or newer. Both the server and libpq are affected.

Avoid race condition with process ID tracking on Windows (Thomas Munro)

The operating system could recycle a PID before the postmaster observed that that child process was gone. This could lead to tracking more than one child with the same PID, resulting in confusion.

Add missing cases to SPI_result_code_string() (Dean Rasheed)

Fix erroneous Valgrind markings in AllocSetRealloc() (Karina Litskevich)

In the unusual case where the size of a large (>8kB) palloc chunk is decreased, a Valgrind-aware build would mismark the defined-ness state of the memory released from the chunk, possibly causing incorrect results during Valgrind testing.

Avoid assertion failure when decoding a transactional logical replication message (Tomas Vondra)

Avoid locale sensitivity when processing regular expression escapes (Jeff Davis)

A backslash followed by a non-ASCII character could sometimes cause an assertion failure, depending on the prevailing locale.

Avoid trying to write an empty WAL record in log_newpage_range() when the last few pages in the specified range are empty (Matthias van de Meent)

It is not entirely clear whether this case is reachable in released branches, but if it is then an assertion failure could occur.

Tighten array dimensionality checks when converting Perl list structures to multi-dimensional SQL arrays (Tom Lane)

plperl could misbehave when the nesting of sub-lists is inconsistent so that the data does not represent a rectangular array of values. Such cases now produce errors, but previously they could result in a crash or garbage output.

Tighten array dimensionality checks when converting Python list structures to multi-dimensional SQL arrays (Tom Lane)

plpython could misbehave when dealing with empty sub-lists, or when the nesting of sub-lists is inconsistent so that the data does not represent a rectangular array of values. The former should result in an empty output array, and the latter in an error. But some cases resulted in a crash, and others in unexpected output.

Fix unwinding of exception stack in plpython (Xing Guo)

Some rare failure cases could return without cleaning up the PG_TRY exception stack, risking a crash if another error was raised before the next stack level was unwound.

Fix possible data corruption in ecpg programs built with the -C ORACLE option (Kyotaro Horiguchi)

When ecpg_get_data() is called with varcharsize set to zero, it could write a terminating zero character into the last byte of the preceding field, truncating the data in that field.

Fix pg_dump so that partitioned tables that are hash-partitioned on an enum-type column can be restored successfully (Tom Lane)

Since the hash codes for enum values depend on the OIDs assigned to the enum, they are typically different after a dump and restore, meaning that rows often need to go into a different partition than they were in originally. Users can work around that by specifying the --load-via-partition-root option; but since there is very little chance of success without that, teach pg_dump to apply it automatically to such tables.

Also, fix pg_restore to not try to TRUNCATE target tables before restoring into them when --load-via-partition-root mode is used. This avoids a hazard of deadlocks and lost data.

In contrib/hstore_plpython, avoid crashing if the Python value to be transformed isn't a mapping (Dmitry Dolgov, Tom Lane)

This should give an error, but Python 3 changed some APIs in a way that caused the check to misbehave, allowing a crash to ensue.

Fix misbehavior in contrib/pg_trgm with an unsatisfiable regular expression (Tom Lane)

A regex such as $foo is legal but unsatisfiable; the regex compiler recognizes that and produces an empty NFA graph. Attempting to optimize such a graph into a pg_trgm GIN or GiST index qualification resulted in accessing off the end of a work array, possibly leading to crashes.

Use the --strip-unneeded option when stripping static libraries with GNU-compatible strip (Tom Lane)

Previously, make install-strip used the -x option in this case. This change avoids misbehavior of llvm-strip, and gives slightly smaller output as well.

Stop recommending auto-download of DTD files for building the documentation, and indeed disable it (Aleksander Alekseev, Peter Eisentraut, Tom Lane)

It appears no longer possible to build the SGML documentation without a local installation of the DocBook DTD files. Formerly xsltproc could download those files on-the-fly from sourceforge.net; but sourceforge.net now permits only HTTPS access, and no common version of xsltproc supports that. Hence, remove the bits of our documentation suggesting that that's possible or useful, and instead add xsltproc's --nonet option to the build recipes.

When running TAP tests in PGXS builds, use a saner location for the temporary portlock directory (Peter Eisentraut)

Place it under tmp_check in the build directory. With the previous coding, a PGXS build would try to place it in the installation directory, which is not necessarily writable.

Update time zone data files to tzdata release 2023c for DST law changes in Egypt, Greenland, Morocco, and Palestine.

When observing Moscow time, Europe/Kirov and Europe/Volgograd now use the abbreviations MSK/MSD instead of numeric abbreviations, for consistency with other timezones observing Moscow time. Also, America/Yellowknife is no longer distinct from America/Edmonton; this affects some pre-1948 timestamps in that area.