When using GSSAPI encryption in non-blocking mode, libpq sometimes
failed with "GSSAPI caller failed to retransmit all data needing
to be retried". The cause is that pqPutMsgEnd rounds its transmit
request down to an even multiple of 8K, and sometimes that can lead
to not requesting a write of data that was requested to be written
(but reported as not written) earlier. That can upset pg_GSS_write's
logic for dealing with not-yet-written data, since it's possible
the data in question had already been incorporated into an encrypted
packet that we weren't able to send during the previous call.
We could fix this with a one-or-two-line hack to disable pqPutMsgEnd's
round-down behavior, but that seems like making the caller work around
a behavior that pg_GSS_write shouldn't expose in this way. Instead,
adjust pg_GSS_write to never report a partial write: it either
reports a complete write, or reflects the failure of the lower-level
pqsecure_raw_write call. The requirement still exists for the caller
to present at least as much data as on the previous call, but with
the caller-visible write start point not moving there is no temptation
for it to present less. We lose some ability to reclaim buffer space
early, but I doubt that that will make much difference in practice.
This also gets rid of a rather dubious assumption that "any
interesting failure condition (from pqsecure_raw_write) will recur
on the next try". We've not seen failure reports traceable to that,
but I've never trusted it particularly and am glad to remove it.
Make the same adjustments to the equivalent backend routine
be_gssapi_write(). It is probable that there's no bug on the backend
side, since we don't have a notion of nonblock mode there; but we
should keep the logic the same to ease future maintenance.
Per bug #18210 from Lars Kanis. Back-patch to all supported branches.
Discussion: https://postgr.es/m/18210-4c6d0b14627f2eb8@postgresql.org
If an error is thrown after calling CreateWaitEventSet(), the memory
of a WaitEventSet is free'd as it's allocated in the short-lived
memory context, but the file descriptor (on epoll- or kqueue-based
systems) or handles (on Windows) that it contains are leaked.
Use PG_TRY-FINALLY to ensure it gets freed. (On master, I will apply a
better fix, using ResourceOwners to track the WaitEventSet, but that's
not backpatchable.)
The added test doesn't check for leaking resources, so it passed even
before this commit. But at least it covers the code path.
In the passing, fix misleading comment on what the 'nevents' argument
to WaitEventSetWait means.
Report by Alexander Lakhin, analysis and suggestion for the fix by Tom
Lane. Fixes bug #17828. Backpatch to v14 where async execution was
introduced, but master gets a different fix.
Discussion: https://www.postgresql.org/message-id/17828-122da8cba23236be@postgresql.org
Discussion: https://www.postgresql.org/message-id/472235.1678387869@sss.pgh.pa.us
The copy command formed for initial sync was using parenthesis for tables
with no columns leading to syntax error. This patch avoids adding
parenthesis for such tables.
Reported-by: Justin G
Author: Vignesh C
Reviewed-by: Peter Smith, Amit Kapila
Backpatch-through: 15
Discussion: http://postgr.es/m/18203-df37fe354b626670@postgresql.org
As written, the query checked for an access method of type 's', which is
not an AM type supported in the core code.
Error introduced by 8586bf7ed8. As this query is not checking what it
should, backpatch all the way down.
Reviewed-by: Aleksander Alekseev
Discussion: https://postgr.es/m/ZVxJkAJrKbfHETiy@paquier.xyz
Backpatch-through: 12
The DROP STATISTICS code failed to properly lock the table, leading to
ERROR: tuple concurrently deleted
when executed concurrently with ANALYZE.
Fixed by modifying RemoveStatisticsById() to acquire the same lock as
ANALYZE. This function is called only by DROP STATISTICS, as ANALYZE
calls RemoveStatisticsDataById() directly.
Reported by Justin Pryzby, fix by me. Backpatch through 12. The code was
like this since it was introduced in 10, but older releases are EOL.
Reported-by: Justin Pryzby
Reviewed-by: Tom Lane
Backpatch-through: 12
Discussion: https://postgr.es/m/ZUuk-8CfbYeq6g_u@pryzbyj2023
Commits 146604ec43 and a898b409f6 added overflow checks to
interval_mul(), but not to interval_div(), which contains almost
identical code, and so is susceptible to the same kinds of
overflows. In addition, those checks did not catch all possible
overflow conditions.
Add additional checks to the "cascade down" code in interval_mul(),
and copy all the overflow checks over to the corresponding code in
interval_div(), so that they both generate "interval out of range"
errors, rather than returning bogus results.
Given that these errors are relatively easy to hit, back-patch to all
supported branches.
Per bug #18200 from Alexander Lakhin, and subsequent investigation.
Discussion: https://postgr.es/m/18200-5ea288c7b2d504b1%40postgresql.org
On the MERGE page, the description of the privileges required could be
taken to imply that the SELECT privilege is required on all columns of
the data source, whereas actually it is only required on the columns
referred to by conditions or expressions in the MERGE command. Re-word
it to make that a little clearer, and mention expressions as well as
conditions.
Also, add a glossary entry for MERGE, and nearby on the glossary page,
mention MERGE in the list of commands that cannot update a
materialized view.
Noted by Jian He. Patch by me, reviewed by Jian He.
Discussion: https://postgr.es/m/CACJufxHuSoRXKwr0MtSFLXuT2nFVWcVfEWhxg7qdP9h%2Bs3a%2BUw%40mail.gmail.com
When performing inlining LLVM unfortunately "leaks" types (the
types survive and are usable, but a new round of inlining will
recreate new structurally equivalent types). This accumulation
will over time amount to a memory leak which for some queries
can be large enough to trigger the OOM process killer.
To avoid accumulation of types, all IR related data is stored
in an LLVMContextRef which is dropped and recreated in order
to release all types. Dropping and recreating incurs overhead,
so it will be done only after 100 queries. This is a heuristic
which might be revisited, but until we can get the size of the
context from LLVM we are flying a bit blind.
This issue has been reported several times, there may be more
references to it in the archives on top of the threads linked
below.
This is a backpatch of 9dce22033d to all supported branches.
Reported-By: Justin Pryzby <pryzby@telsasoft.com>
Reported-By: Kurt Roeckx <kurt@roeckx.be>
Reported-By: Jaime Casanova <jcasanov@systemguards.com.ec>
Reported-By: Lauri Laanmets <pcspets@gmail.com>
Author: Andres Freund and Daniel Gustafsson
Discussion: https://postgr.es/m/7acc8678-df5f-4923-9cf6-e843131ae89d@www.fastmail.com
Discussion: https://postgr.es/m/20201218235607.GC30237@telsasoft.com
Discussion: https://postgr.es/m/CAPH-tTxLf44s3CvUUtQpkDr1D8Hxqc2NGDzGXS1ODsfiJ6WSqA@mail.gmail.com
Backpatch-through: v12
contain_mutable_functions and contain_volatile_functions give
reliable answers only after expression preprocessing (specifically
eval_const_expressions). Some places understand this, but some did
not get the memo --- which is not entirely their fault, because the
problem is documented only in places far away from those functions.
Introduce wrapper functions that allow doing the right thing easily,
and add commentary in hopes of preventing future mistakes from
copy-and-paste of code that's only conditionally safe.
Two actual bugs of this ilk are fixed here. We failed to preprocess
column GENERATED expressions before checking mutability, so that the
code could fail to detect the use of a volatile function
default-argument expression, or it could reject a polymorphic function
that is actually immutable on the datatype of interest. Likewise,
column DEFAULT expressions weren't preprocessed before determining if
it's safe to apply the attmissingval mechanism. A false negative
would just result in an unnecessary table rewrite, but a false
positive could allow the attmissingval mechanism to be used in a case
where it should not be, resulting in unexpected initial values in a
new column.
In passing, re-order the steps in ComputePartitionAttrs so that its
checks for invalid column references are done before applying
expression_planner, rather than after. The previous coding would
not complain if a partition expression contains a disallowed column
reference that gets optimized away by constant folding, which seems
to me to be a behavior we do not want.
Per bug #18097 from Jim Keener. Back-patch to all supported versions.
Discussion: https://postgr.es/m/18097-ebb179674f22932f@postgresql.org
The fallback implementation of pg_atomic_test_set_flag() that uses
atomic-exchange gives pg_atomic_exchange_u32_impl() an extra
argument. This issue has been present since the introduction of
the atomics API in commit b64d92f1a5.
Reviewed-by: Andres Freund
Discussion: https://postgr.es/m/20231114035439.GA1809032%40nathanxps13
Backpatch-through: 12
checkExtensionMembership() set the DUMP_COMPONENT_SECLABEL and
DUMP_COMPONENT_POLICY flags for extension member objects, even though
we lack any infrastructure for tracking extensions' initial settings
of these properties. This is not OK. The result was that a dump
would always include commands to set these properties for extension
objects that have them, with at least three negative consequences:
1. The restoring user might not have privilege to set these properties
on these objects.
2. The properties might be incorrect/irrelevant for the version of the
extension that's installed in the destination database.
3. The dump itself might fail, in the case of RLS properties attached
to extension tables that the dumping user lacks privilege to LOCK.
(That's because we must get at least AccessShareLock to ensure that
we don't fail while trying to decompile the RLS expressions.)
When and if somebody cares to invent initial-state infrastructure for
extensions' RLS policies and security labels, we could think about
finding another way around problem #3. But in the absence of such
infrastructure, this whole thing is just wrong and we shouldn't do it.
(Note: this applies only to ordinary dumps; binary-upgrade dumps
still dump and restore extension member objects separately, with
all properties.)
Tom Lane and Jacob Champion. Back-patch to all supported branches.
Discussion: https://postgr.es/m/00d46a48-3324-d9a0-49bf-e7f0f11d1038@timescale.com
Clarify that default privileges are not inherited and reorder
paragraphs. This is a follow up to a recent ALTER DEFAULT PRIVILEGES
doc patch.
Reported-by: Sanjay Minni
Diagnosed-by: AMpxBo=M35hcH1g4Vg=KRJ0-77FOJcvdrdiVF5KSOAdOG-LvKQ@mail.gmail.com
Co-authored-by: Laurenz Albe
Backpatch-through: 16
It's clearly stated in the comments that ginFindParents() must keep
the pin on the index's root page that's associated with the topmost
GinBtreeStack item. However, the code path for the case that the
desired downlink has been pushed down to the next index level
ignored this proviso, and would release the pin anyway if we were
still examining the root level. That led to an assertion failure
or "buffer NNNN is not owned by resource owner" error later, when
we try to release the pin again at the end of the insertion.
This is quite hard to reproduce, since it can only happen if an
index root page split occurs concurrently with our own insertion.
Thanks to Jeff Janes for finding a test case that triggers it
often enough to allow investigation.
This has been there since the beginning of GIN, so back-patch
to all supported branches.
Discussion: https://postgr.es/m/CAMkU=1yCAKtv86dMrD__Ja-7KzjE=uMeKX8y__cx5W-OEWy2ow@mail.gmail.com
One of the examples on the SELECT page was missing a semicolon from
a listing which has the look and feel of being a psql session. This
adds the missing semicolon and also removes the newline between the
query and results to match the other examples nearby.
Backpatch to all supported branches to avoid backpatching issues on
this page.
Reported-by: tim.needham2@gmail.com
Discussion: https://postgr.es/m/169965004097.225187.12941375915673151540@wrigleys.postgresql.org
Backpatch-through: v12
Commit b7eda3e0e moved XidInMVCCSnapshot() from tqual.c into snapmgr.c,
but follow-up commit c91560def incorrectly updated this reference. We
could fix it, but as pointed out by Daniel Gustafsson, 1) the reader can
easily find the file that contains the definition of that function, e.g.
by grepping, and 2) this kind of reference is prone to going stale; so
let's just remove it.
Back-patch to all supported branches.
Reviewed by Daniel Gustafsson.
Discussion: https://postgr.es/m/CAPmGK145VdKkPBLWS2urwhgsfidbSexwY-9zCL6xSUJH%2BBTUUg%40mail.gmail.com
We can simplify FieldSelect on a whole-row Var into a plain Var
for the selected field. However, we should copy the whole-row Var's
varnullingrels when we do so, because the new Var is clearly nullable
by exactly the same rels as the original. Failure to do this led to
errors like "wrong varnullingrels (b) (expected (b 3)) for Var 2/2".
Richard Guo, per bug #18184 from Marian Krucina. Back-patch to
v16 where varnullingrels was introduced.
Discussion: https://postgr.es/m/18184-5868dd258782058e@postgresql.org
When executing a MERGE UPDATE action, if the UPDATE is turned into a
cross-partition DELETE then INSERT, do not attempt to invoke AFTER
UPDATE ROW triggers, or any of the other post-update actions in
ExecUpdateEpilogue().
For consistency with a plain UPDATE command, such triggers should not
be fired (and typically fail anyway), and similarly, other post-update
actions, such as WCO/RLS checks should not be executed, and might also
lead to unexpected failures.
Therefore, as with ExecUpdate(), make ExecMergeMatched() return
immediately if ExecUpdateAct() reports that a cross-partition update
was done, to be sure that no further processing is done for that
tuple.
Back-patch to v15, where MERGE was introduced.
Discussion: https://postgr.es/m/CAEZATCWjBgagyNZs02vgDF0DvASYj-iHTFtXG2-nP3orZhmtcw%40mail.gmail.com
When computing "0 - INT64_MIN", most platforms would report an
overflow error, which is correct. However, platforms without integer
overflow builtins or 128-bit integers would fail to spot the overflow,
and incorrectly return INT64_MIN.
Back-patch to all supported branches.
Patch be me. Thanks to Jian He for initial investigation, and Laurenz
Albe and Tom Lane for review.
Discussion: https://postgr.es/m/CAEZATCUNK-AZSD0jVdgkk0N%3DNcAXBWeAEX-QU9AnJPensikmdQ%40mail.gmail.com
When PQsendFlushRequest() was added by commit 69cf1d5429, we argued
against adding a PQflush() call in it[1]. This is still the right
decision: if the user wants a flush to occur, they can just call that.
However, we failed to realize that the message bytes could still be
given to the kernel for transmitting when this can be made without
blocking. That's what pqPipelineFlush() does, and it is done for every
single other message type sent by libpq, so do that.
(When the socket is in blocking mode this may indeed block, but that's
what all the other libpq message-sending routines do, too.)
[1] https://www.postgresql.org/message-id/202106252352.5ca4byasfun5%40alvherre.pgsql
Author: Jelte Fennema-Nio <postgres@jeltef.nl>
Discussion: https://postgr.es/m/CAGECzQTxZRevRWkKodE-SnJk1Yfm4eKT+8E4Cyq3MJ9YKTnNew@mail.gmail.com
`openssl` is an optional dependency in the meson build as it may not be
installed in an environment even if SSL libraries are around. The meson
scripts assume that, but the SSL tests thought that it was a hard
dependency, causing a meson installation to fail if `openssl` could not
be found. Like similar tests that depend on external commands, and to
be consistent with ./configure for the SSL tests, this commit makes the
command existence optional in the tests.
Author: Tristan Partin
Discussion: https://postgr.es/m/CWSX6P5OUUM5.N7B74KQ06ZP6@neon.tech
Backpatch-through: 16
false_positive_rate is a parameter that can be set with the bloom
opclass in BRIN, and setting it to a value of exactly 0.25 would trigger
an assertion in the first INSERT done on the index with value set.
The assertion changed here relied on BLOOM_{MIN|MAX}_FALSE_POSITIVE_RATE
that are somewhat arbitrary values, and specifying an out-of-range value
would also trigger a failure when defining such an index. So, as-is,
the assertion was just doubling on the min-max check of the reloption.
This is now enlarged to check that it is a correct percentage value,
instead, based on a suggestion by Tom Lane.
Author: Alexander Lakhin
Reviewed-by: Tom Lane, Shihao Zhong
Discussion: https://postgr.es/m/17969-a6c54de48026d694@postgresql.org
Backpatch-through: 14
array_set_element() and related functions allow an array to be
enlarged by assigning to subscripts outside the current array bounds.
While these places were careful to check that the new bounds are
allowable, they neglected to consider the risk of integer overflow
in computing the new bounds. In edge cases, we could compute new
bounds that are invalid but get past the subsequent checks,
allowing bad things to happen. Memory stomps that are potentially
exploitable for arbitrary code execution are possible, and so is
disclosure of server memory.
To fix, perform the hazardous computations using overflow-detecting
arithmetic routines, which fortunately exist in all still-supported
branches.
The test cases added for this generate (after patching) errors that
mention the value of MaxArraySize, which is platform-dependent.
Rather than introduce multiple expected-files, use psql's VERBOSITY
parameter to suppress the printing of the message text. v11 psql
lacks that parameter, so omit the tests in that branch.
Our thanks to Pedro Gallegos for reporting this problem.
Security: CVE-2023-5869
transformAggregateCall() captures the datatypes of the aggregate's
arguments immediately to construct the Aggref.aggargtypes list.
This seems reasonable because the arguments have already been
transformed --- but there is an edge case where they haven't been.
Specifically, if we have an unknown-type literal in an ANY argument
position, nothing will have been done with it earlier. But if we
also have DISTINCT, then addTargetToGroupList() converts the literal
to "text" type, resulting in the aggargtypes list not matching the
actual runtime type of the argument. The end result is that the
aggregate tries to interpret a "text" value as being of type
"unknown", that is a zero-terminated C string. If the text value
contains no zero bytes, this could result in disclosure of server
memory following the text literal value.
To fix, move the collection of the aggargtypes list to the end
of transformAggregateCall(), after DISTINCT has been handled.
This requires slightly more code, but not a great deal.
Our thanks to Jingzhou Fu for reporting this problem.
Security: CVE-2023-5868
It was always false in single-user mode, in autovacuum workers, and in
background workers. This had no specifically-identified security
consequences, but non-core code or future work might make it
security-relevant. Back-patch to v11 (all supported versions).
Jelte Fennema-Nio. Reported by Jelte Fennema-Nio.
Documentation says it cannot signal "a backend owned by a superuser".
On the contrary, it could signal background workers, including the
logical replication launcher. It could signal autovacuum workers and
the autovacuum launcher. Block all that. Signaling autovacuum workers
and those two launchers doesn't stall progress beyond what one could
achieve other ways. If a cluster uses a non-core extension with a
background worker that does not auto-restart, this could create a denial
of service with respect to that background worker. A background worker
with bugs in its code for responding to terminations or cancellations
could experience those bugs at a time the pg_signal_backend member
chooses. Back-patch to v11 (all supported versions).
Reviewed by Jelte Fennema-Nio. Reported by Hemanth Sandrana and
Mahendrakar Srinivasarao.
Security: CVE-2023-5870
In f13eb16485 I made a mistake leading to only man1 being installed. I will
report a bug suggesting that meson warn about mistakes of this sort.
Reported-by: Christoph Berg <myon@debian.org>
Discussion: https://postgr.es/m/ZUU5pRQO6ZUeBsi6@msg.df7cb.de
Backpatch: 16-, where the meson build was introduced
As usual, the release notes for other branches will be made by cutting
these down, but put them up for community review first.
Also as usual for a .1 release, there are some entries here that
are not really relevant for v16 because they already appeared in 16.0.
Those'll be removed later.
This text left one with the impression that an ON SELECT rule could
be attached to a plain table, which has not been true since commit
264c06820 (meaning the text was already misleading when written,
evidently by me in 96bd67f61). However, it didn't get really bad
until b23cd185f removed the convert-a-table-to-a-view logic, which
had made it possible for scripts that thought they were attaching
ON SELECTs to tables to still work.
Rewrite into a form that makes it clear that an ON SELECT rule
is better regarded as an implementation detail of a view.
Pre-v16, point out that adding ON SELECT to a table actually
converts it to a view.
Per bug #18178 from Joshua Uyehara. Back-patch to all supported
branches.
Discussion: https://postgr.es/m/18178-05534d7064044d2d@postgresql.org
get_explain_guc_options() crashed if a string GUC marked GUC_EXPLAIN
has a NULL boot_val. Nosing around found a couple of other places
that seemed insufficiently cautious about NULL string values, although
those are likely unreachable in practice. Add some commentary
defining the expectations for NULL values of string variables,
in hopes of forestalling future additions of more such bugs.
Xing Guo, Aleksander Alekseev, Tom Lane
Discussion: https://postgr.es/m/CACpMh+AyDx5YUpPaAgzVwC1d8zfOL4JoD-uyFDnNSa1z0EsDQQ@mail.gmail.com
The test missed that custom GUCs need to be ignored from the list of
parameters that can exist in postgresql.conf.sample. This caused the
test to fail on a server where such a module is loaded, when using
EXTRA_INSTALL and TEMP_CONFIG, for instance.
Author: Anton A. Melnikov
Discussion: https://postgr.es/m/fc5509ce-5144-4dac-8d13-21793da44fc5@postgrespro.ru
Backpatch-through: 15
Bruce Momjian