Recent versions of the Linux system header files cause xlogdefs.h to
believe that open_datasync should be the default sync method, whereas
formerly fdatasync was the default on Linux. open_datasync is a bad
choice, first because it doesn't actually outperform fdatasync (in fact
the reverse), and second because we try to use O_DIRECT with it, causing
failures on certain filesystems (e.g., ext4 with data=journal option).
This part of the patch is largely per a proposal from Marti Raudsepp.
More extensive changes are likely to follow in HEAD, but this is as much
change as we want to back-patch.
Also clean up confusing code and incorrect documentation surrounding the
fsync_writethrough option. Those changes shouldn't result in any actual
behavioral change, but I chose to back-patch them anyway to keep the
branches looking similar in this area.
In 9.0 and HEAD, also do some copy-editing on the WAL Reliability
documentation section.
Back-patch to all supported branches, since any of them might get used
on modern Linux versions.
There are some code paths, such as SPI_execute(), where we invoke
copyObject() on raw parse trees before doing parse analysis on them. Since
the bison grammar is capable of building heavily nested parsetrees while
itself using only minimal stack depth, this means that copyObject() can be
the front-line function that hits stack overflow before anything else does.
Accordingly, it had better have a check_stack_depth() call. I did a bit of
performance testing and found that this slows down copyObject() by only a
few percent, so the hit ought to be negligible in the context of complete
processing of a query.
Per off-list report from Toshihide Katayama. Back-patch to all supported
branches.
There were corner cases in which the planner would attempt to inline such
a function, which would result in a failure at runtime due to loss of
information about exactly what the result record type is. Fix by disabling
inlining when the function's recorded result type is RECORD. There might
be some sub-cases where inlining could still be allowed, but this is a
simple and backpatchable fix, so leave refinements for another day.
Per bug #5777 from Nate Carson.
Back-patch to all supported branches. 8.1 happens to avoid a core-dump
here, but it still does the wrong thing.
temporary indexes are not WAL-logged. We used a constant LSN for temporary
indexes, on the assumption that we don't need to worry about concurrent page
splits in temporary indexes because they're only visible to the current
session. But that assumption is wrong, it's possible to insert rows and
split pages in the same session, while a scan is in progress. For example,
by opening a cursor and fetching some rows, and INSERTing new rows before
fetching some more.
Fix by generating fake increasing LSNs, used in place of real LSNs in
temporary GiST indexes.
This is needed to support debug_print_parse, per report from Jon Nelson.
Cursory testing via the regression tests suggests we aren't missing
anything else.
Once we have found a non-null constant argument, there is no need to
examine additional arguments of the COALESCE. The previous coding got it
right only if the constant was in the first argument position; otherwise
it tried to simplify following arguments too, leading to unexpected
behavior like this:
regression=# select coalesce(f1, 42, 1/0) from int4_tbl;
ERROR: division by zero
It's a minor corner case, but a bug is a bug, so back-patch all the way.
location read from backup label file can be found: wasShutdown was set
incorrectly when a backup label file was found.
Jeff Davis, with a little tweaking by me.
This code was just plain wrong: what you got was not a line through the
given point but a line almost indistinguishable from the Y-axis, although
not truly vertical. The only caller that tries to use this function with
m == DBL_MAX is dist_ps_internal for the case where the lseg is horizontal;
it would end up producing the distance from the given point to the place
where the lseg's line crosses the Y-axis. That function is used by other
operators too, so there are several operators that could compute wrong
distances from a line segment to something else. Per bug #5745 from
jindiax.
Back-patch to all supported branches.
The general design of memory management in Postgres is that intermediate
results computed by an expression are not freed until the end of the tuple
cycle. For expression indexes, ANALYZE has to re-evaluate each expression
for each of its sample rows, and it wasn't bothering to free intermediate
results until the end of processing of that index. This could lead to very
substantial leakage if the intermediate results were large, as in a recent
example from Jakub Ouhrabka. Fix by doing ResetExprContext for each sample
row. This necessitates adding a datumCopy step to ensure that the final
expression value isn't recycled too. Some quick testing suggests that this
change adds at worst about 10% to the time needed to analyze a table with
an expression index; which is annoying, but seems a tolerable price to pay
to avoid unexpected out-of-memory problems.
Back-patch to all supported branches.
Per recent investigation, the register stack can grow faster than the
regular stack depending on compiler and choice of options. To avoid
crashes we must check both stacks in check_stack_depth().
Back-patch to all supported versions.
Some buildfarm members fail the test with the original depth of 10 levels,
apparently because they are running at the minimum max_stack_depth setting
of 100kB and using ~ 10k per recursion level. While it might be
interesting to try to figure out why they're eating so much stack, it isn't
likely that any fix for that would be back-patchable. So just change the
test to recurse only 5 levels. The extra levels don't prove anything
correctness-wise anyway.
We failed to record any dependency on the underlying table for an index
declared like "create index i on t (foo(t.*))". This would create trouble
if the table were dropped without previously dropping the index. To fix,
simplify some overly-cute code in index_create(), accepting the possibility
that sometimes the whole-table dependency will be redundant. Also document
this hazard in dependency.c. Per report from Kevin Grittner.
In passing, prevent a core dump in pg_get_indexdef() if the index's table
can't be found. I came across this while experimenting with Kevin's
example. Not sure it's a real issue when the catalogs aren't corrupt, but
might as well be cautious.
Back-patch to all supported versions.
In general, expression execution state trees aren't re-entrantly usable,
since functions can store private state information in them.
For efficiency reasons, plpgsql tries to cache and reuse state trees for
"simple" expressions. It can get away with that most of the time, but it
can fail if the state tree is dirty from a previous failed execution (as
in an example from Alvaro) or is being used recursively (as noted by me).
Fix by tracking whether a state tree is in use, and falling back to the
"non-simple" code path if so. This results in a pretty considerable speed
hit when the non-simple path is taken, but the available alternatives seem
even more unpleasant because they add overhead in the simple path. Per
idea from Heikki.
Back-patch to all supported branches.
that WAL file containing the checkpoint redo-location can be found. This
avoids making the cluster irrecoverable if the redo location is in an earlie
WAL file than the checkpoint record.
Report, analysis and patch by Jeff Davis, with small changes by me.
There are numerous methods by which a Perl or Tcl function can subvert
the behavior of another such function executed later; for example, by
redefining standard functions or operators called by the target function.
If the target function is SECURITY DEFINER, or is called by such a
function, this means that any ordinary SQL user with Perl or Tcl language
usage rights can do essentially anything with the privileges of the target
function's owner.
To close this security hole, create a separate Perl or Tcl interpreter for
each SQL userid under which plperl or pltcl functions are executed within
a session. However, all plperlu or pltclu functions run within a session
still share a single interpreter, since they all execute at the trust
level of a database superuser anyway.
Note: this change results in a functionality loss when libperl has been
built without the "multiplicity" option: it's no longer possible to call
plperl functions under different userids in one session, since such a
libperl can't support multiple interpreters in one process. However, such
a libperl already failed to support concurrent use of plperl and plperlu,
so it's likely that few people use such versions with Postgres.
Security: CVE-2010-3433
It now emerges that the JDBC driver expects to be able to use pg_get_expr()
on an output of a sub-SELECT. So extend the check logic to be able to recurse
into a sub-SELECT to see if the argument is ultimately coming from an
appropriate column. Per report from Thomas Kellerer.
hasn't been set.
The only known case where this can happen is when show_session_authorization
is invoked in an autovacuum process, which is possible if an index function
calls it, as for example in bug #5669 from Andrew Geery. We could perhaps
try to return a sensible value, such as the name of the cluster-owning
superuser; but that seems like much more trouble than the case is worth,
and in any case it could create new possible failure modes. Simply
returning an empty string seems like the most appropriate fix.
Back-patch to all supported versions, even those before autovacuum, just
in case there's another way to provoke this crash.
The previous patches failed to cover a lot of symlinks that are only
added in platform-specific cases. Make the lists match what's in the
Makefile for each branch.
Egypt and Palestine. Added new names for two Micronesian timezones:
Pacific/Chuuk is now preferred over Pacific/Truk (and the preferred
abbreviation is CHUT not TRUT) and Pacific/Pohnpei is preferred over
Pacific/Ponape. Historical corrections for Finland.
returning "record" actually do have the same rowtype. This is needed because
the parser can't realistically enforce that they will all have the same typmod,
as seen in a recent example from David Wheeler.
Back-patch to 8.0, which is as far back as we have the notion of RECORD
subtypes being distinguished by typmod. Wheeler's example depends on
8.4-and-up features, but I suspect there may be ways to provoke similar
failures before 8.4.
This is reproducibly possible in Python 2.7 if the user turned
PendingDeprecationWarning into an error, but it's theoretically also possible
in earlier versions in case of exceptional conditions.
backpatched to 8.0
socket lockfile) when writing them. The lack of an fsync here may well
explain two different reports we've seen of corrupted lockfile contents,
which doesn't particularly bother the running server but can prevent a
new server from starting if the old one crashes. Per suggestion from
Alvaro.
Back-patch to all supported versions.
in particular, propagate a fix in the test to see whether a UTF8 character has
length 4 bytes. This is likely of little real-world consequence because
5-or-more-byte UTF8 sequences are not supported by Postgres nor seen anywhere
in the wild, but still we may as well get it right. Problem found by Joseph
Adams.
Bug is aboriginal, so back-patch all the way.
expressions. We need to deal with this when handling subscripts in an array
assignment, and also when catching an exception. In an Assert-enabled build
these omissions led to Assert failures, but I think in a normal build the
only consequence would be short-term memory leakage; which may explain why
this wasn't reported from the field long ago.
Back-patch to all supported versions. 7.4 doesn't have exceptions, but
otherwise these bugs go all the way back.
Heikki Linnakangas and Tom Lane
look through join alias Vars to avoid breaking join queries, and
move the test to someplace where it will catch more possible ways
of calling a function. We still ought to throw away the whole thing
in favor of a data-type-based solution, but that's not feasible in
the back branches.
Completion of back-port of my patch of yesterday.
assuming that a local char[] array would be aligned on at least a word
boundary. There are architectures on which that is pretty much guaranteed to
NOT be the case ... and those arches also don't like non-aligned memory
accesses, meaning that log_newpage() would crash if it ever got invoked.
Even on Intel-ish machines there's a potential for a large performance penalty
from doing I/O to an inadequately aligned buffer. So palloc it instead.
Backpatch to 8.0 --- 7.4 doesn't have this code.
If a zeroed page is present in the heap, ALTER TABLE .. SET TABLESPACE will
set the LSN and TLI while copying it, which is wrong, and heap_xlog_newpage()
will do the same thing during replay, so the corruption propagates to any
standby. Note, however, that the bug can't be demonstrated unless archiving
is enabled, since in that case we skip WAL logging altogether, and the LSN/TLI
are not set.
Back-patch to 8.0; prior releases do not have tablespaces.
Analysis and patch by Jeff Davis. Adjustments for back-branches and minor
wordsmithing by me.
a pass-by-reference datatype with a nontrivial projection step.
We were using the same memory context for the projection operation as for
the temporary context used by the hashtable routines in execGrouping.c.
However, the hashtable routines feel free to reset their temp context at
any time, which'd lead to destroying input data that was still needed.
Report and diagnosis by Tao Ma.
Back-patch to 8.1, where the problem was introduced by the changes that
allowed us to work with "virtual" tuples instead of materializing intermediate
tuple values everywhere. The earlier code looks quite similar, but it doesn't
suffer the problem because the data gets copied into another context as a
result of having to materialize ExecProject's output tuple.
loop from being dropped, I missed subtransaction cleanup. Pinned portals
must be dropped at subtransaction cleanup just as they are at main
transaction cleanup.
Per bug #5556 by Robert Walker. Backpatch to 8.0, 7.4 didn't have
subtransactions.
use the actual element type of the array it's disassembling, rather than
trusting the type OID passed in by its caller. This is needed because
sometimes the planner passes in a type OID that's only binary-compatible
with the target column's type, rather than being an exact match. Per an
example from Bernd Helmle.
Possibly we should refactor get_attstatsslot/free_attstatsslot to not expect
the caller to supply type ID data at all, but for now I'll just do the
minimum-change fix.
Back-patch to 7.4. Bernd's test case only crashes back to 8.0, but since
these subroutines are the same in 7.4, I suspect there may be variant
cases that would crash 7.4 as well.
sub-select contains a join alias reference that expands into an expression
containing another sub-select. Per yesterday's report from Merlin Moncure
and subsequent off-list investigation.
Back-patch to 7.4. Older versions didn't attempt to flatten sub-selects in
ways that would trigger this problem.
being used in a PL/pgSQL FOR loop is closed was inadequate, as Tom Lane
pointed out. The bug affects FOR statement variants too, because you can
close an implicitly created cursor too by guessing the "<unnamed portal X>"
name created for it.
To fix that, "pin" the portal to prevent it from being dropped while it's
being used in a PL/pgSQL FOR loop. Backpatch all the way to 7.4 which is
the oldest supported version.
but we have nevertheless exposed them to users via pg_get_expr(). It would
be too much maintenance effort to rigorously check the input, so put a hack
in place instead to restrict pg_get_expr() so that the argument must come
from one of the system catalog columns known to contain valid expressions.
Per report from Rushabh Lathia. Backpatch to 7.4 which is the oldest
supported version at the moment.
This saves cycles in get_ps_display() on many popular platforms, and more
importantly ensures that get_ps_display() will correctly return an empty
string if init_ps_display() hasn't been called yet. Per trouble report
from Ray Stell, in which log_line_prefix %i produced junk early in backend
startup.
Back-patch to 8.0. 7.4 doesn't have %i and its version of get_ps_display()
makes no pretense of avoiding pad junk anyhow.
that is a regular table or view owned by a superuser. This prevents a
trojan horse attack whereby any unprivileged SQL user could create such a
table and insert code into it that would then get executed in other users'
sessions whenever they call pltcl functions.
Worse yet, because the code was automatically loaded into both the "normal"
and "safe" interpreters at first use, the attacker could execute unrestricted
Tcl code in the "normal" interpreter without there being any pltclu functions
anywhere, or indeed anyone else using pltcl at all: installing pltcl is
sufficient to open the hole. Change the initialization logic so that the
"unknown" code is only loaded into an interpreter when the interpreter is
first really used. (That doesn't add any additional security in this
particular context, but it seems a prudent change, and anyway the former
behavior violated the principle of least astonishment.)
Security: CVE-2010-1170
fundamentally insecure. Instead apply an opmask to the whole interpreter that
imposes restrictions on unsafe operations. These restrictions are much harder
to subvert than is Safe.pm, since there is no container to be broken out of.
Backported to release 7.4.
In releases 7.4, 8.0 and 8.1 this also includes the necessary backporting of
the two interpreters model for plperl and plperlu adopted in release 8.2.
In versions 8.0 and up, the use of Perl's POSIX module to undo its locale
mangling on Windows has become insecure with these changes, so it is
replaced by our own routine, which is also faster.
Nice side effects of the changes include that it is now possible to use perl's
"strict" pragma in a natural way in plperl, and that perl's $a and
$b variables now work as expected in sort routines, and that function
compilation is significantly faster.
Tim Bunce and Andrew Dunstan, with reviews from Alex Hunsaker and
Alexey Klyukin.
Security: CVE-2010-1169
Marc G. Fournier
Peter Eisentraut
Tom Lane
Heikki Linnakangas
Magnus Hagander
Robert Haas
Andrew Dunstan