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
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
This part of the documentation refers to exceptions as handled by
PL/pgSQL, and using the internal error code is confusing.
Per thinko in 66bde49d96.
Reported-by: Euler Taveira, Bruce Momjian
Discussion: https://postgr.es/m/ZUEUnLevXyW7DlCs@momjian.us
Backpatch-through: 11
pgstatindex failed with ERRCODE_DATA_CORRUPTED, of the "can't-happen"
class XX. The other functions succeeded on an empty index; they might
have malfunctioned if the failed index build left torn I/O or other
complex state. Report an ERROR in statistics functions pgstatindex,
pgstatginindex, pgstathashindex, and pgstattuple. Report DEBUG1 and
skip all index I/O in maintenance functions brin_desummarize_range,
brin_summarize_new_values, brin_summarize_range, and
gin_clean_pending_list. Back-patch to v11 (all supported versions).
Discussion: https://postgr.es/m/20231001195309.a3@google.com
This prevents false-positive reports about "the first child of leftmost
target page is not leftmost of its level", "block %u is not leftmost"
and "left link/right link pair". They appeared if amcheck ran before
VACUUM cleaned things, after a cluster exited recovery between the
first-stage and second-stage WAL records of a deletion. Back-patch to
v11 (all supported versions).
Reviewed by Peter Geoghegan.
Discussion: https://postgr.es/m/20231005025232.c7.nmisch@google.com
Formerly, the value computed by leftmostvalue_interval() was a long
way short of the minimum possible interval value. As a result, an
index scan on a GIN index on an interval column with < or <= operators
would miss large negative interval values.
Fix by setting all fields of the leftmost interval to their minimum
values, ensuring that the result is less than any other possible
interval. Since this only affects index searches, no index rebuild is
necessary.
Back-patch to all supported branches.
Dean Rasheed, reviewed by Heikki Linnakangas.
Discussion: https://postgr.es/m/CAEZATCV80%2BgOfF8ehNUUfaKBZgZMDfCfL-g1HhWGb6kC3rpDfw%40mail.gmail.com
When looping around after finding that the set-returning function
returned zero rows for the current input tuple, ExecProjectSet
neglected to reset either of the two memory contexts it's
responsible for cleaning out. Typically this wouldn't cause much
problem, because once the SRF does return at least one row, the
contexts would get reset on the next call. However, if the SRF
returns no rows for many input tuples in succession, quite a lot
of memory could be transiently consumed.
To fix, make sure we reset both contexts while looping around.
Per bug #18172 from Sergei Kornilov. Back-patch to all supported
branches.
Discussion: https://postgr.es/m/18172-9b8c5fc1d676ded3@postgresql.org
Debian recently decided to split out a bunch of "obsolete" timezone
names into a new tzdata-legacy package, which isn't installed by
default. One of these zone names is Pacific/Enderbury, and that
breaks our regression tests (on --with-system-tzdata builds)
because our default timezone abbreviations list defines PHOT as
Pacific/Enderbury.
Pacific/Enderbury got renamed to Pacific/Kanton in tzdata 2021b,
so that in distros that still have this entry it's just a symlink
to Pacific/Kanton anyway. So one answer would be to redefine PHOT
as Pacific/Kanton. However, then things would fail if the
installed tzdata predates 2021b, which is recent enough that that
seems like a real problem.
Instead, let's just remove PHOT from the default list. That seems
likely to affect nobody in the real world, because (a) it was an
abbreviation that the tzdb crew made up in the first place, with
no evidence of real-world usage, and (b) the total human population
of the Phoenix Islands is less than two dozen persons, per Wikipedia.
If anyone does use this zone abbreviation they can easily put it back
via a custom abbreviations file.
We'll keep PHOT in the Pacific.txt reference file, but change it
to Pacific/Kanton there, as that definition seems more likely to
be useful to future readers of that file.
Per report from Victor Wagner. Back-patch to all supported
branches.
Discussion: https://postgr.es/m/20231027152049.4b5c8044@wagner.wagner.home
As far as I can see, ecpg has no notion of a "default" open
connection. You can do "CONNECT TO DEFAULT" but that just specifies
letting libpq use all its default connection parameters --- the
resulting connection is not special subsequently. In particular,
SET CONNECTION = DEFAULT and DISCONNECT DEFAULT simply act on a
connection named DEFAULT, if you've made one; they do not have
special lookup rules. But the documentation of these commands
makes it look like they do.
Simplest fix, I think, is just to remove the paras suggesting that
DEFAULT is special here.
Also, SET CONNECTION *does* have one special lookup rule, which
is that it recognizes CURRENT as an alias for the currently selected
connection. SET CONNECTION = CURRENT is a no-op, so it's pretty
useless, but nonetheless it does something different from selecting
a connection by name; so we'd better document it.
Per report from Sylvain Frandaz. Back-patch to all supported
versions.
Discussion: https://postgr.es/m/169824721149.1769274.1553568436817652238@wrigleys.postgresql.org
When scanning build farm results, it's useful to be able to see which
version is in use. For the Meson build system, this information was
already displayed.
Back-patch to all supported branches.
Discussion: https://postgr.es/m/4022690.1697852728%40sss.pgh.pa.us
This avoids a compiler bug occurring in AIX's xlc, even in pretty
late-model revisions. Buildfarm testing has now confirmed that
only 64-bit xlc is affected. Although we are contemplating
dropping support for xlc in v17, it's still supported in the
back branches, so we need this fix.
Back-patch of code changes from HEAD commit 19fa97731.
(The test cases were already back-patched, in 4a427b82c et al.)
Discussion: https://postgr.es/m/CA+hUKGK=DOC+hE-62FKfZy=Ybt5uLkrg3zCZD-jFykM-iPn8yw@mail.gmail.com
This doco said that use of => as an operator "is deprecated".
It's been fully disallowed since 865f14a2d back in 9.5, but
evidently that commit missed updating this statement.
Do so now.
This commit (c290e79cf0) was originally back-patched to v15.
Commit 97550c0711 added a new use of STDERR_FILENO, and it was
back-patched all the way to v11, thus breaking MSVC builds for v11
through v14. Since STDERR_FILENO is now needed on older versions,
let's back-patch c290e79cf0 down to v11, too.
Here follows the original commit message describing the change:
Because they are not available we've used _fileno(stdin) in some places, but
that doesn't reliably work, because stdin might be closed. This is the
prerequisite of the subsequent commit, fixing a failure introduced in
76e38b37a5.
Author: Andres Freund <andres@anarazel.de>
Reported-By: Sandeep Thakkar <sandeep.thakkar@enterprisedb.com>
Message-Id: 20220520164558.ozb7lm6unakqzezi@alap3.anarazel.de (on pgsql-packagers)
Discussion: https://postgr.es/m/20231017164517.GA613565%40nathanxps13
Backpatch-through: 11
Per code coverage reports, we had zero regression test coverage
of these functions. That came back to bite us, as apparently
that's allowed us to miss discovering misbehavior of this code
with AIX's xlc compiler. Install relevant portions of the
test cases added in 97957fdba, 2f0472030, 19fa97731.
(Assuming the expected outcome that the xlc problem does appear
in back branches, a code fix will follow.)
Discussion: https://postgr.es/m/CA+hUKGK=DOC+hE-62FKfZy=Ybt5uLkrg3zCZD-jFykM-iPn8yw@mail.gmail.com
The SIGTERM handler for the startup process immediately calls
proc_exit() for the duration of the restore_command, i.e., a call
to system(). This system() call forks a new process to execute the
shell command, and this child process inherits the parent's signal
handlers. If both the parent and child processes receive SIGTERM,
both will attempt to call proc_exit(). This can end badly. For
example, both processes will try to remove themselves from the
PGPROC shared array.
To fix this problem, this commit adds a check in
StartupProcShutdownHandler() to see whether MyProcPid == getpid().
If they match, this is the parent process, and we can proc_exit()
like before. If they do not match, this is a child process, and we
just emit a message to STDERR (in a signal safe manner) and
_exit(), thereby skipping any problematic exit callbacks.
This commit also adds checks in proc_exit(), ProcKill(), and
AuxiliaryProcKill() that verify they are not being called within
such child processes.
Suggested-by: Andres Freund
Reviewed-by: Thomas Munro, Andres Freund
Discussion: https://postgr.es/m/Y9nGDSgIm83FHcad%40paquier.xyz
Discussion: https://postgr.es/m/20230223231503.GA743455%40nathanxps13
Backpatch-through: 11
Dropping a temp table could entail TOAST table access to clean out
toasted catalog entries, such as large pg_constraint.conbin strings
for complex CHECK constraints. If we did that via ON COMMIT DROP,
we triggered the assertion in init_toast_snapshot(), because
there was no provision for setting up a snapshot for the drop
actions. Fix that.
(I assume here that the adjacent truncation actions for ON COMMIT
DELETE ROWS don't have a similar problem: it doesn't seem like
nontransactional truncations would need to touch any toasted fields.
If that proves wrong, we could refactor a bit to have the same
snapshot acquisition cover that too.)
The test case added here does not fail before v15, because that
assertion was added in 277692220 which was not back-patched.
However, the race condition the assertion warns of surely
exists further back, so back-patch to all supported branches.
Per report from Richard Guo.
Discussion: https://postgr.es/m/CAMbWs4-x26=_QxxgdJyNbiCDzvtr2WV5ZDso_v-CukKEe6cBZw@mail.gmail.com
Commit dc7d70ea added functions that read the control file, but didn't
acquire ControlFileLock. With unlucky timing, file systems that have
weak interlocking like ext4 and ntfs could expose partially overwritten
contents, and the checksum would fail.
Back-patch to all supported releases.
Reviewed-by: David Steele <david@pgmasters.net>
Reviewed-by: Anton A. Melnikov <aamelnikov@inbox.ru>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/20221123014224.xisi44byq3cf5psi%40awork3.anarazel.de
This could only affect HASH partitioned tables with at least 2 partition
key columns.
If partition pruning was delayed until execution and the query contained
an IS NULL qual on one of the partitioned keys, and some subsequent
partitioned key was being compared to a non-Const, then this could result
in a crash due to the incorrect keyno being used to calculate the
stateidx for the expression evaluation code.
Here we fix this by properly skipping partitioned keys which have a
nullkey set. Effectively, this must be the same as what's going on
inside perform_pruning_base_step().
Sergei Glukhov also provided a patch, but that's not what's being used
here.
Reported-by: Sergei Glukhov
Reviewed-by: tender wang, Sergei Glukhov
Discussion: https://postgr.es/m/d05b26fa-af54-27e1-f693-6c31590802fa@postgrespro.ru
Backpatch-through: 11, where runtime partition pruning was added.
get_steps_using_prefix_recurse() incorrectly assumed that it could stop
recursive processing of the 'prefix' list when cur_keyno was one before
the step_lastkeyno. Since hash partition pruning can prune using IS
NULL quals, and these IS NULL quals are not present in the 'prefix'
list, then that logic could cause more levels of recursion than what is
needed and lead to there being no more items in the 'prefix' list to
process. This would manifest itself as a crash in some code that
expected the 'start' ListCell not to be NULL.
Here we adjust the logic so that instead of stopping recursion at 1 key
before the step_lastkeyno, we just look at the llast(prefix) item and
ensure we only recursively process up until just before whichever the last
key is. This effectively allows keys to be missing in the 'prefix' list.
This change does mean that step_lastkeyno is no longer needed, so we
remove that from the static functions. I also spent quite some time
reading this code and testing it to try to convince myself that there
are no other issues. That resulted in the irresistible temptation of
rewriting some comments, many of which were just not true or inconcise.
Reported-by: Sergei Glukhov
Reviewed-by: Sergei Glukhov, tender wang
Discussion: https://postgr.es/m/2f09ce72-315e-2a33-589a-8519ada8df61@postgrespro.ru
Backpatch-through: 11, where partition pruning was introduced.
While these two built-in functions do exactly the same thing,
CURRENT_USER seems preferable to use in documentation examples.
It's easier to look up if the reader is unsure what it is.
Also, this puts these examples in sync with an adjacent example
that already used CURRENT_USER.
Per question from Kirk Parker.
Discussion: https://postgr.es/m/CANwZ8rmN_Eb0h0hoMRS8Feftaik0z89PxVsKg+cP+PctuOq=Qg@mail.gmail.com
In a selective restore, ACLs for a table should be dumped if the
table is selected to be dumped. However, if the table has both
table-level and column-level ACLs, only the table-level ACL was
restored. This happened because _tocEntryRequired assumed that
an ACL could have only one dependency (the one on its table),
and punted if there was more than one. But since commit ea9125304,
column-level ACLs also depend on the table-level ACL if any, to
ensure correct ordering in parallel restores. To fix, adjust the
logic in _tocEntryRequired to ignore dependencies on ACLs.
I extended a test case in 002_pg_dump.pl so that it purports to
test for this; but in fact the test passes even without the fix.
That's because this bug only manifests during a selective restore,
while the scenarios 002_pg_dump.pl tests include only selective dumps.
Perhaps somebody would like to extend the script so that it can test
scenarios including selective restore, but I'm not touching that.
Euler Taveira and Tom Lane, per report from Kong Man.
Back-patch to all supported branches.
Discussion: https://postgr.es/m/DM4PR11MB73976902DBBA10B1D652F9498B06A@DM4PR11MB7397.namprd11.prod.outlook.com
After receiving position data for a lexeme, tsvectorrecv()
advanced its "datalen" value by (npos+1)*sizeof(WordEntry)
where the correct calculation is (npos+1)*sizeof(WordEntryPos).
This accidentally failed to render the constructed tsvector
invalid, but it did result in leaving some wasted space
approximately equal to the space consumed by the position data.
That could have several bad effects:
* Disk space is wasted if the received tsvector is stored into a
table as-is.
* A legal tsvector could get rejected with "maximum total lexeme
length exceeded" if the extra space pushes it over the MAXSTRPOS
limit.
* In edge cases, the finished tsvector could be assigned a length
larger than the allocated size of its palloc chunk, conceivably
leading to SIGSEGV when the tsvector gets copied somewhere else.
The odds of a field failure of this sort seem low, though valgrind
testing could probably have found this.
While we're here, let's express the calculation as
"sizeof(uint16) + npos * sizeof(WordEntryPos)" to avoid the type
pun implicit in the "npos + 1" formulation. It's not wrong
given that WordEntryPos had better be 2 bytes to avoid padding
problems, but it seems clearer this way.
Report and patch by Denis Erokhin. Back-patch to all supported
versions.
Discussion: https://postgr.es/m/009801d9f2d9$f29730c0$d7c59240$@datagile.ru
Add "-gmt 1" to our test invocations of the Tcl "clock" command,
so that they do not consult the timezone environment. While it
doesn't really matter which timezone is used here, it does
matter that the command not fall over entirely. We've now
discovered that at least on FreeBSD, "clock scan" will fail if
/etc/localtime is missing. It seems worth making the test
insensitive to that.
Per Tomas Vondras' buildfarm animal dikkop. Thanks to
Thomas Munro for the diagnosis.
Discussion: https://postgr.es/m/316d304a-1dcd-cea1-3d6c-27f794727a06@enterprisedb.com
As of Xcode 15 (macOS Sonoma), the linker complains about duplicate
references to the same library. We see warnings about libpgport and
libpgcommon being duplicated in many client executables. This is a
consequence of the hack introduced in commit 6b7ef076b to list
libpgport before libpq while not removing it from $(LIBS).
(Commit 8396447cd later applied the same rule to libpgcommon.)
The concern in 6b7ef076b was to ensure that the client executable
wouldn't unintentionally depend on pgport functions from libpq.
That concern is obsolete on any platform for which we can do symbol
export control, because if we can then the pgport functions in libpq
won't be exposed anyway. Hence, we can fix this problem by just
removing libpgport and libpgcommon from $(libpq_pgport), and letting
clients depend on the occurrences in $(LIBS).
In the back branches, do that only on macOS (which we know has
symbol export control). In HEAD, let's be more aggressive and
remove the extra libraries everywhere. The only still-supported
platforms that lack export control are MinGW/Cygwin, and it
doesn't seem worth sweating over ABI stability details for those
(or if somebody does care, it'd probably be possible to perform
symbol export control for those too). As well as being simpler,
this might give some microscopic improvement in build time.
The meson build system is not changed here, as it doesn't have
this particular disease, though it does have some related issues
that we'll fix separately.
Discussion: https://postgr.es/m/467042.1695766998@sss.pgh.pa.us
Commit 7d3b7011b added a link to the statistics functions, which at the
time were anchored under the section for statistics views. aebe989477
added a separate section for statistics functions, but the link was not
updated to point to the new anchor. Fix by changing the xref.
Backpatch to all supported branches.
Author: Peter Smith <peter.b.smith@fujitsu.com>
Discussion: https://postgr.es/m/CAHut+Ptr0jKzNNtWnssLq+3jNhbyaBseqf6NPrWHk08mQFRoTg@mail.gmail.com
Backpatch-through: 11
nbtree's mark/restore processing failed to correctly handle an edge case
involving array key advancement and related search-type scan key state.
Scans with ScalarArrayScalarArrayOpExpr quals requiring mark/restore
processing (for a merge join) could incorrectly conclude that an
affected array/scan key must not have advanced during the time between
marking and restoring the scan's position.
As a result of all this, array key handling within btrestrpos could skip
a required call to _bt_preprocess_keys(). This confusion allowed later
primitive index scans to overlook tuples matching the true current array
keys. The scan's search-type scan keys would still have spurious values
corresponding to the final array element(s) -- not values matching the
first/now-current array element(s).
To fix, remember that "array key wraparound" has taken place during the
ongoing btrescan in a flag variable stored in the scan's state, and use
that information at the point where btrestrpos decides if another call
to _bt_preprocess_keys is required.
Oversight in commit 70bc5833, which taught nbtree to handle array keys
during mark/restore processing, but missed this subtlety. That commit
was itself a bug fix for an issue in commit 9e8da0f7, which taught
nbtree to handle ScalarArrayOpExpr quals natively.
Author: Peter Geoghegan <pg@bowt.ie>
Discussion: https://postgr.es/m/CAH2-WzkgP3DDRJxw6DgjCxo-cu-DKrvjEv_ArkP2ctBJatDCYg@mail.gmail.com
Backpatch: 11- (all supported branches).
This code was sloppy about comparison of index columns that
are expressions. It didn't reliably reject cases where one
index has an expression where the other has a plain column,
and it could index off the start of the attmap array, leading
to a Valgrind complaint (though an actual crash seems unlikely).
I'm not sure that the expression-vs-column sloppiness leads
to any visible problem in practice, because the subsequent
comparison of the two expression lists would reject cases
where the indexes have different numbers of expressions
overall. Maybe we could falsely match indexes having the
same expressions in different column positions, but it'd
require unlucky contents of the word before the attmap array.
It's not too surprising that no problem has been reported
from the field. Nonetheless, this code is clearly wrong.
Per bug #18135 from Alexander Lakhin. Back-patch to all
supported branches.
Discussion: https://postgr.es/m/18135-532f4a755e71e4d2@postgresql.org
We started to use this linker switch in commit 9df308697 of
2004-07-13, which was in the OS X 10.3 era. Apparently it's been a
no-op since around OS X 10.9. Apple's most recent toolchain version
actively complains about it, so it's time to get rid of it.
Discussion: https://postgr.es/m/467042.1695766998@sss.pgh.pa.us
Tom Lane