When using a pipeline, a transaction starts from the first command and
is committed with a Sync message or when the pipeline ends.
Functions like IsInTransactionBlock() or PreventInTransactionBlock()
were already able to understand a pipeline as being in a transaction
block, but it was not the case of CheckTransactionBlock(). This
function is called for example to generate a WARNING for SET LOCAL,
complaining that it is used outside of a transaction block.
The current state of the code caused multiple problems, like:
- SET LOCAL executed at any stage of a pipeline issued a WARNING, even
if the command was at least second in line where the pipeline is in a
transaction state.
- LOCK TABLE failed when invoked at any step of a pipeline, even if it
should be able to work within a transaction block.
The pipeline protocol assumes that the first command of a pipeline is
not part of a transaction block, and that any follow-up commands is
considered as within a transaction block.
This commit changes the backend so as an implicit transaction block is
started each time the first Execute message of a pipeline has finished
processing, with this implicit transaction block ended once a sync is
processed. The checks based on XACT_FLAGS_PIPELINING in the routines
checking if we are in a transaction block are not necessary: it is
enough to rely on the existing ones.
Some tests are added to pgbench, that can be backpatched down to v17
when \syncpipeline is involved and down to v14 where \startpipeline and
\endpipeline are available. This is unfortunately limited regarding the
error patterns that can be checked, but it provides coverage for various
pipeline combinations to check if these succeed or fail. These tests
are able to capture the case of SET LOCAL's WARNING. The author has
proposed a different feature to improve the coverage by adding similar
meta-commands to psql where error messages could be checked, something
more useful for the cases where commands cannot be used in transaction
blocks, like REINDEX CONCURRENTLY or VACUUM. This is considered as
future work for v18~.
Author: Anthonin Bonnefoy
Reviewed-by: Jelte Fennema-Nio, Michael Paquier
Discussion: https://postgr.es/m/CAO6_XqrWO8uNBQrSu5r6jh+vTGi5Oiyk4y8yXDORdE2jbzw8xw@mail.gmail.com
Backpatch-through: 13
Many process environment variables (e.g. PATH), bypass the containment
expected of a trusted PL. Hence, trusted PLs must not offer features
that achieve setenv(). Otherwise, an attacker having USAGE privilege on
the language often can achieve arbitrary code execution, even if the
attacker lacks a database server operating system user.
To fix PL/Perl, replace trusted PL/Perl %ENV with a tied hash that just
replaces each modification attempt with a warning. Sites that reach
these warnings should evaluate the application-specific implications of
proceeding without the environment modification:
Can the application reasonably proceed without the modification?
If no, switch to plperlu or another approach.
If yes, the application should change the code to stop attempting
environment modifications. If that's too difficult, add "untie
%main::ENV" in any code executed before the warning. For example,
one might add it to the start of the affected function or even to
the plperl.on_plperl_init setting.
In passing, link to Perl's guidance about the Perl features behind the
security posture of PL/Perl.
Back-patch to v12 (all supported versions).
Andrew Dunstan and Noah Misch
Security: CVE-2024-10979
This commit changes libpq so that errors reported by the backend during
the protocol negotiation for SSL and GSS are discarded by the client, as
these may include bytes that could be consumed by the client and write
arbitrary bytes to a client's terminal.
A failure with the SSL negotiation now leads to an error immediately
reported, without a retry on any other methods allowed, like a fallback
to a plaintext connection.
A failure with GSS discards the error message received, and we allow a
fallback as it may be possible that the error is caused by a connection
attempt with a pre-11 server, GSS encryption having been introduced in
v12. This was a problem only with v17 and newer versions; older
versions discard the error message already in this case, assuming a
failure caused by a lack of support for GSS encryption.
Author: Jacob Champion
Reviewed-by: Peter Eisentraut, Heikki Linnakangas, Michael Paquier
Security: CVE-2024-10977
Backpatch-through: 12
The previous wording is easy to read incorrectly; this change makes it
simpler, less ambiguous, and less prominent.
Backpatch to all live branches.
Reviewed-by: Amit Langote <amitlangote09@gmail.com>
Discussion: https://postgr.es/m/202411051201.zody6mld7vkw@alvherre.pgsql
There are two functions that can be used in event triggers to get more
details about a rewrite happening on a relation. Both had a limited
documentation:
- pg_event_trigger_table_rewrite_reason() and
pg_event_trigger_table_rewrite_oid() were not mentioned in the main
event trigger section in the paragraph dedicated to the event
table_rewrite.
- pg_event_trigger_table_rewrite_reason() returns an integer which is a
bitmap of the reasons why a rewrite happens. There was no explanation
about the meaning of these values, forcing the reader to look at the
code to find out that these are defined in event_trigger.h.
While on it, let's add a comment in event_trigger.h where the
AT_REWRITE_* are defined, telling to update the documentation when
these values are changed.
Backpatch down to 13 as a consequence of 1ad23335f3, where this area
of the documentation has been heavily reworked.
Author: Greg Sabino Mullane
Discussion: https://postgr.es/m/CAKAnmmL+Z6j-C8dAx1tVrnBmZJu+BSoc68WSg3sR+CVNjBCqbw@mail.gmail.com
Backpatch-through: 13
Disabling enable_indexscan has always also disabled Index Only Scans.
Here we make that more clear in the documentation in an attempt to
prevent future complaints complaining about this expected behavior.
Reported-by: Melanie Plageman
Author: David G. Johnston, David Rowley
Backpatch-through: 12, oldest supported version
Discussion: https://postgr.es/m/CAAKRu_atV=kovgpaLREyG68PB5+ncKvJ2UNoeRetEgyC3Yb5Sw@mail.gmail.com
There were unnecessary non-breaking spaces (nbsp, U+00A0, 0xc2a0 in
UTF-8) in the docs. This commit replaces them with ASCII spaces
(0x20).
config.sgml is backpatched through 17.
ref/drop_extension.sgml is backpatched through 13.
Discussion: https://postgr.es/m/20240930.153404.202479334310259810.ishii%40postgresql.org
Reviewed-by: Yugo Nagata, Daniel Gustafsson
Backpatch-through: 17, 13
FYI, during PDF builds, this link type generates a "Unresolved ID
reference found" warning because it is suppressed from the PDF output.
Backpatch-through: 12
Historically we've used timezone "PST8PDT", but the recent release
2024b of tzdb changes the definition of that zone in a way that
breaks many test cases concerned with dates before 1970. Although
we've not yet adopted 2024b into our own tree, this is already
problematic for people using --with-system-tzdata if their platform
has already adopted 2024b. To work with both older and newer
versions of tzdb, switch to using "America/Los_Angeles", accepting
the ensuing changes in regression test results.
Back-patch to all supported branches.
Per report and patch from Wolfgang Walther.
Discussion: https://postgr.es/m/0a997455-5aba-4cf2-a354-d26d8bcbfae6@technowledgy.de
This change improves the description of the
restrict_nonsystem_relation_kind parameter in guc_table.c and the
documentation for better clarity.
Backpatch to 12, where this GUC parameter was introduced.
Reviewed-by: Peter Eisentraut
Discussion: https://postgr.es/m/6a96f1af-22b4-4a80-8161-1f26606b9ee2%40eisentraut.org
Backpatch-through: 12
The descriptions for ProcArrayGroupUpdate and XactGroupUpdate claim
that these events mean we are waiting for the group leader "at end
of a parallel operation," but neither pertains to parallel
operations. This commit reverts these descriptions to their
wording before commit 3048898e73, i.e., "end of a parallel
operation" is changed to "transaction end."
Author: Sameer Kumar
Reviewed-by: Amit Kapila
Discussion: https://postgr.es/m/CAGPeHmh6UMrKQHKCmX%2B5vV5TH9P%3DKw9en3k68qEem6J%3DyrZPUA%40mail.gmail.com
Backpatch-through: 13
This section claims we use CRC-32 for WAL records and two-phase
state files, but we've actually used CRC-32C since v9.5 (commit
5028f22f6e). Fix that.
Reviewed-by: Robert Haas
Discussion: https://postgr.es/m/ZrUFpLP-w2zTAHqq%40nathan
Backpatch-through: 12
When pg_dump retrieves the list of database objects and performs the
data dump, there was possibility that objects are replaced with others
of the same name, such as views, and access them. This vulnerability
could result in code execution with superuser privileges during the
pg_dump process.
This issue can arise when dumping data of sequences, foreign
tables (only 13 or later), or tables registered with a WHERE clause in
the extension configuration table.
To address this, pg_dump now utilizes the newly introduced
restrict_nonsystem_relation_kind GUC parameter to restrict the
accesses to non-system views and foreign tables during the dump
process. This new GUC parameter is added to back branches too, but
these changes do not require cluster recreation.
Back-patch to all supported branches.
Reviewed-by: Noah Misch
Security: CVE-2024-7348
Backpatch-through: 12
Prior to this commit, the docs for enable_partitionwise_aggregate and
enable_partitionwise_join mentioned the additional overheads enabling
these causes for the query planner, but they mentioned nothing about the
possible surge in work_mem-consuming executor nodes that could end up in
the final plan. Dimitrios reported the OOM killer intervened on his
query as a result of using enable_partitionwise_aggregate=on.
Here we adjust the docs to mention the possible increase in the number of
work_mem-consuming executor nodes that can appear in the final plan as a
result of enabling these GUCs.
Reported-by: Dimitrios Apostolou
Reviewed-by: Ashutosh Bapat
Discussion: https://postgr.es/m/3603c380-d094-136e-e333-610914fb3e80%40gmx.net
Discussion: https://postgr.es/m/CAApHDvoZ0_yqwPFEpb6h261L76BUpmh5GxBQq0LeRzQ5Jh3zzg@mail.gmail.com
Backpatch-through: 12, oldest supported version
We were not being clear about which variants of the "direction"
clause are permitted in MOVE. Also, the text seemed to be
written with only the FETCH/MOVE NEXT case in mind, so it
didn't apply very well to other variants.
Also, document that "MOVE count IN cursor" only works if count
is a constant. This is not the whole truth, because some other
cases such as a parenthesized expression will also work, but
we want to push people to use "MOVE FORWARD count" instead.
The constant case is enough to cover what we allow in plain SQL,
and that seems sufficient to claim support for.
Update a comment in pl_gram.y claiming that we don't document
that point.
Per gripe from Philipp Salvisberg.
Discussion: https://postgr.es/m/172155553388.702.7932496598218792085@wrigleys.postgresql.org
State explicitly that the coordinates in our geometric data types are
float8. Also explain that polygons store their bounding box.
While here, fix the table of geometric data types to show type
"line"'s size correctly: it's 24 bytes not 32. This has somehow
escaped notice since that table was made in 1998.
Per suggestion from Sebastian Skałacki. The size error seems
important enough to justify back-patching.
Discussion: https://postgr.es/m/172000045661.706.1822177575291548794@wrigleys.postgresql.org
The ssl_prefer_server_ciphers setting is quite important from a
security point of view, so simply stating that older versions
doesn't have it isn't very helpful. This adds the version when
the GUC was added to help readers.
Backpatch to all supported versions since this setting has been
around since 9.4.
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/5D7E0F5E-E620-4D54-8788-66D421AC76F0@yesql.se
Backpatch-through: v12
If the CALL is within an atomic context (e.g. there's an outer
transaction block), _SPI_execute_plan should acquire a fresh snapshot
to execute any such functions with. We failed to do that and instead
passed them the Portal snapshot, which had been acquired at the start
of the current SQL command. This'd lead to seeing stale values of
rows modified since the start of the command.
This is arguably a bug in 84f5c2908: I failed to see that "are we in
non-atomic mode" needs to be defined the same way as it is further
down in _SPI_execute_plan, i.e. check !_SPI_current->atomic not just
options->allow_nonatomic. Alternatively the blame could be laid on
plpgsql, which is unconditionally passing allow_nonatomic = true
for CALL/DO even when it knows it's in an atomic context. However,
fixing it in spi.c seems like a better idea since that will also fix
the problem for any extensions that may have copied plpgsql's coding
pattern.
While here, update an obsolete comment about _SPI_execute_plan's
snapshot management.
Per report from Victor Yegorov. Back-patch to all supported versions.
Discussion: https://postgr.es/m/CAGnEboiRe+fG2QxuBO2390F7P8e2MQ6UyBjZSL_w1Cej+E4=Vw@mail.gmail.com
The documentation for POSIX semaphores is missing a reference to
max_wal_senders. This commit fixes that in the same way that
commit 4ebe51a5fb fixed the same issue in the documentation for
System V semaphores.
Discussion: https://postgr.es/m/20240517164452.GA1914161%40nathanxps13
Backpatch-through: 12
The formulas for SEMMNI and SEMMNS do not include the archiver
process, which was converted to an auxiliary process in v14, and
the WAL summarizer process, which was introduced in v17. This
commit corrects these formulas and adds a missing reference to
max_wal_senders nearby. Since this section of the documentation
tends to be incorrect quite often, we should likely give up on
documenting the exact formulas in favor of something less fragile,
but that is left as a future exercise.
Reported-by: Sami Imseih
Reviewed-by: Sami Imseih
Discussion: https://postgr.es/m/20240517164452.GA1914161%40nathanxps13
Backpatch-through: 12
Parameter column_name must be an existing column because ALTER
MATERIALIZED VIEW cannot add new columns. The old description was
likely copied from ALTER TABLE.
Author: Erik Wienhold
Discussion: https://postgr.es/m/6880ca53-7961-4eeb-86d5-6bd05fc2027e@ewie.name
Backpatch-through: 12
Commit 695b4a113a added a dependency on retrieving oldestxid from
pg_control, which only exists in 9.0 and onwards, but the check for
8.4 as the oldest version was retained. Since there has been few if
any complaints of 8.4 upgrades not working, fix by setting 9.0 as
the oldest version supported rather than resurrecting 8.4 support.
Backpatch to all supported versions.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/1973418.1657040382@sss.pgh.pa.us
Backpatch-through: v12
Specifically, it terminates a background worker even if the caller
couldn't terminate the background worker with pg_terminate_backend().
Commit 3a9b18b309 neglected to update
this. Back-patch to v13, which introduced DROP DATABASE FORCE.
Reviewed by Amit Kapila. Reported by Kirill Reshke.
Discussion: https://postgr.es/m/20240429212756.60.nmisch@google.com
The catalog view pg_stats_ext fails to consider privileges for
expression statistics. The catalog view pg_stats_ext_exprs fails
to consider privileges and row-level security policies. To fix,
restrict the data in these views to table owners or roles that
inherit privileges of the table owner. It may be possible to apply
less restrictive privilege checks in some cases, but that is left
as a future exercise. Furthermore, for pg_stats_ext_exprs, do not
return data for tables with row-level security enabled, as is
already done for pg_stats_ext.
On the back-branches, a fix-CVE-2024-4317.sql script is provided
that will install into the "share" directory. This file can be
used to apply the fix to existing clusters.
Bumps catversion on 'master' branch only.
Reported-by: Lukas Fittl
Reviewed-by: Noah Misch, Tomas Vondra, Tom Lane
Security: CVE-2024-4317
Backpatch-through: 14
Michael Paquier