libxslt offers the ability to read and write both files and URLs through
stylesheet commands, thus allowing unprivileged database users to both read
and write data with the privileges of the database server. Disable that
through proper use of libxslt's security options.
Also, remove xslt_process()'s ability to fetch documents and stylesheets
from external files/URLs. While this was a documented "feature", it was
long regarded as a terrible idea. The fix for CVE-2012-3489 broke that
capability, and rather than expend effort on trying to fix it, we're just
going to summarily remove it.
While the ability to write as well as read makes this security hole
considerably worse than CVE-2012-3489, the problem is mitigated by the fact
that xslt_process() is not available unless contrib/xml2 is installed,
and the longstanding warnings about security risks from that should have
discouraged prudent DBAs from installing it in security-exposed databases.
Reported and fixed by Peter Eisentraut.
Security: CVE-2012-3488
It failed to check for error return from xsltApplyStylesheet(), as reported
by Peter Gagarinov. (So far as I can tell, libxslt provides no convenient
way to get a useful error message in failure cases. There might be some
inconvenient way, but considering that this code is deprecated it's hard to
get enthusiastic about putting lots of work into it. So I just made it say
"failed to apply stylesheet", in line with the existing error checks.)
While looking at the code I also noticed that the string returned by
xsltSaveResultToString was never freed, resulting in a session-lifespan
memory leak.
Back-patch to all supported versions.
Overly tight coding caused the password transformation loop to stop
examining input once it had processed a byte equal to 0x80. Thus, if the
given password string contained such a byte (which is possible though not
highly likely in UTF8, and perhaps also in other non-ASCII encodings), all
subsequent characters would not contribute to the hash, making the password
much weaker than it appears on the surface.
This would only affect cases where applications used DES crypt() to encode
passwords before storing them in the database. If a weak password has been
created in this fashion, the hash will stop matching after this update has
been applied, so it will be easy to tell if any passwords were unexpectedly
weak. Changing to a different password would be a good idea in such a case.
(Since DES has been considered inadequately secure for some time, changing
to a different encryption algorithm can also be recommended.)
This code, and the bug, are shared with at least PHP, FreeBSD, and OpenBSD.
Since the other projects have already published their fixes, there is no
point in trying to keep this commit private.
This bug has been assigned CVE-2012-2143, and credit for its discovery goes
to Rubin Xu and Joseph Bonneau.
dblink_exec leaked temporary database connections if any error occurred
after connection setup, for example
SELECT dblink_exec('...connect string...', 'select 1/0');
Add a PG_TRY block to ensure PQfinish gets done when it is needed.
(dblink_record_internal is on the hairy edge of needing similar treatment,
but seems not to be actively broken at the moment.)
Also, in 9.0 and up, only one of the three functions using tuplestore
return mode was properly checking that the query context would allow
a tuplestore result.
Noted while reviewing dblink patch. Back-patch to all supported branches.
The array intersection code would give wrong results if the first entry of
the correct output array would be "1". (I think only this value could be
at risk, since the previous word would always be a lower-bound entry with
that fixed value.)
Problem spotted by Julien Rouhaud, initial patch by Guillaume Lelarge,
cosmetic improvements by me.
Due to oversights, the encrypt_iv() and decrypt_iv() functions failed to
report certain types of invalid-input errors, and would instead return
random garbage values.
Marko Kreen, per report from Stefan Kaltenbrunner
The original coding examined the next character before verifying that
there *is* a next character. In the worst case with the input buffer
right up against the end of memory, this would result in a segfault.
Problem spotted by Paul Guyot; this commit extends his patch to fix an
additional case. In addition, make the code a tad more readable by not
overloading the usage of *tlen.
Both dict_int and dict_xsyn were blithely assuming that whatever memory
palloc gives back will be pre-zeroed. This would typically work for
just about long enough to run their regression tests, and no longer :-(.
The pre-9.0 code in dict_xsyn was even lamer than that, as it would
happily give back a pointer to the result of palloc(0), encouraging
its caller to access off the end of memory. Again, this would just
barely fail to fail as long as memory contained nothing but zeroes.
Per a report from Rodrigo Hjort that code based on these examples
didn't work reliably.
A similar problem for pgstattuple() was fixed in April of 2010 by commit
33065ef8bc, but pgstatindex() seems to have
been overlooked.
Back-patch all the way, as with that commit, though not to 7.4 through
8.1, since those are now EOL.
For an empty index, the pgstatindex() function would compute 0.0/0.0 for
its avg_leaf_density and leaf_fragmentation outputs. On machines that
follow the IEEE float arithmetic standard with any care, that results in
a NaN. However, per report from Rushabh Lathia, Microsoft couldn't
manage to get this right, so you'd get a bizarre error on Windows.
Fix by forcing the results to be NaN explicitly, rather than relying on
the division operator to give that or the snprintf function to print it
correctly. I have some doubts that this is really the most useful
definition, but it seems better to remain backward-compatible with
those platforms for which the behavior wasn't completely broken.
Back-patch to 8.2, since the code is like that in all current releases.
A password containing a character with the high bit set was misprocessed
on machines where char is signed (which is most). This could cause the
preceding one to three characters to fail to affect the hashed result,
thus weakening the password. The result was also unportable, and failed
to match some other blowfish implementations such as OpenBSD's.
Since the fix changes the output for such passwords, upstream chose
to provide a compatibility hack: password salts beginning with $2x$
(instead of the usual $2a$ for blowfish) are intentionally processed
"wrong" to give the same hash as before. Stored password hashes can
thus be modified if necessary to still match, though it'd be better
to change any affected passwords.
In passing, sync a couple other upstream changes that marginally improve
performance and/or tighten error checking.
Back-patch to all supported branches. Since this issue is already
public, no reason not to commit the fix ASAP.
contrib/intarray's gettoken() uses a fixed-size buffer to collect an
integer's digits, and did not guard against overrunning the buffer.
This is at least a backend crash risk, and in principle might allow
arbitrary code execution. The code didn't check for overflow of the
integer value either, which while not presenting a crash risk was still
bad.
Thanks to Apple Inc's security team for reporting this issue and supplying
the fix.
Security: CVE-2010-4015
After parsing a parenthesized subexpression, we must pop all pending
ANDs and NOTs off the stack, just like the case for a simple operand.
Per bug #5793.
Also fix clones of this routine in contrib/intarray and contrib/ltree,
where input of types query_int and ltxtquery had the same problem.
Back-patch to all supported versions.
Fix the same size_alpha versus size_beta typo that was recently fixed
in contrib/cube. Noted by Alexander Korotkov.
Back-patch to all supported branches (there is a more invasive fix in
HEAD).
Most of the functions that execute XPath queries leaked the data structures
created by libxml2. This memory would not be recovered until end of
session, so it mounts up pretty quickly in any serious use of the feature.
Per report from Pavel Stehule, though this isn't his patch.
Back-patch to all supported branches.
In HEAD, emit a warning when an operator named => is defined.
In both HEAD and the backbranches (except in 8.2, where contrib
modules do not have documentation), document that hstore's text =>
text operator may be removed in a future release, and encourage the
use of the hstore(text, text) function instead. This function only
exists in HEAD (previously, it was called tconvert), so backpatch
it back to 8.2, when hstore was added. Per discussion.
columns correctly. In passing, get rid of some dead logic in the
underlying get_sql_insert() etc functions --- there is no caller that
will pass null value-arrays to them.
Per bug report from Robert Voinea.
dblink_build_sql_insert() and related functions. In particular, be sure to
reject references to dropped and out-of-range column numbers. The numbers
are still interpreted as physical column numbers, though, for backward
compatibility.
This patch replaces Joe's patch of 2010-02-03, which handled only some aspects
of the problem.
lock the target relation just once per SQL function call. The original coding
obtained and released lock several times per call. Aside from saving a
not-insignificant number of cycles, this eliminates possible race conditions
if someone tries to modify the relation's schema concurrently. Also
centralize locking and permission-checking logic.
Problem noted while investigating a trouble report from Robert Voinea --- his
problem is still to be fixed, though.
unsatisfiable query, such as indexcol && empty_array. It should return -1
to tell GIN no scan is required; but silly typo disabled the logic for that,
resulting in unnecessary "GIN indexes do not support whole-index scans" error.
Per bug report from Jeff Trout.
Back-patch to 8.3 where the logic was introduced.
in versions >= 8.3). The core code is more robust and efficient than what
was there before, and this also reduces risks involved in swapping different
libxml error handler settings.
Before 8.3, there is still some risk of problems if add-on modules such as
Perl invoke libxml without setting their own error handler. Given the lack
of reports I'm not sure there's a risk in practice, so I didn't take the
step of actually duplicating the core code into older contrib/xml2 branches.
Instead I just tweaked the existing code to ensure it didn't leave a dangling
pointer to short-lived memory when throwing an error.
This involves modifying the module to have a stable ABI, that is, the
xslt_process() function still exists even without libxslt. It throws a
runtime error if called, but doesn't prevent executing the CREATE FUNCTION
call. This is a good thing anyway to simplify cross-version upgrades.
These are unnecessary and probably dangerous. I don't see any immediate
risk situations in the core XML support or contrib/xml2 itself, but there
could be issues with external uses of libxml2, and in any case it's an
accident waiting to happen.
Prior to 8.3, these changes are not critical for compatibility with core
Postgres, since core had no libxml2 calls then. However there is still
a risk if contrib/xml2 is used along with libxml2 functionality in Perl
or other loadable modules. So back-patch to all versions.
Also back-patch addition of regression tests. I'm not sure how many of
the cases are interesting without the interaction with core xml code,
but a silly regression test is still better than none at all.
The main motivation for changing this is bug #4921, in which it's pointed out
that it's no longer safe to apply ltree operations to the result of
ARRAY(SELECT ...) if the sub-select might return no rows. Before 8.3,
the ARRAY() construct would return NULL, which might or might not be helpful
but at least it wouldn't result in an error. Now it returns an empty array
which results in a failure for no good reason, since the ltree operations
are all perfectly capable of dealing with zero-element arrays.
As far as I can find, these ltree functions are the only places where zero
array dimensionality is rejected unnecessarily.
Back-patch to 8.3 to prevent behavioral regression of queries that worked
in older releases.
the postgres process has permissions to delete the trigger file, per
suggestion by Mason Hale.
Also fix pg_standby to do a more predictable exit(200) instead of the
current exit(-1) when the unlink of the trigger file fails anyway.
This only affects 8.3 branch. Older versions didn't have pg_standby,
and in 8.4 upwards pg_standby is no longer responsible for deleting the
trigger file; it's supposed to be done by recovery_end_command instead.
exceed the total number of non-dropped source table fields for
dblink_build_sql_*(). Addresses bug report from Rushabh Lathia.
Backpatch all the way to the 7.3 branch.
PL/pgSQL function within an exception handler. Make sure we use the right
resource owner when we create the tuplestore to hold returned tuples.
Simplify tuplestore API so that the caller doesn't need to be in the right
memory context when calling tuplestore_put* functions. tuplestore.c
automatically switches to the memory context used when the tuplestore was
created. Tuplesort was already modified like this earlier. This patch also
removes the now useless MemoryContextSwitch calls from callers.
Report by Aleksei on pgsql-bugs on Dec 22 2009. Backpatch to 8.1, like
the previous patch that broke this.
Windows doesn't do signal processing like other platforms do. It never
really worked, but recent changes to the signal handling made it crash.
This fixes bug #4961. Patch by Fujii Masao.
last pair of parameter name/value strings, even when there are MAXPARAMS
of them. Aboriginal bug in contrib/xml2, noted while studying bug #4912
(though I'm not sure whether there's something else involved in that
report).
This might be thought a security issue, since it's a potential backend
crash; but considering that untrustworthy users shouldn't be allowed
to get their hands on xslt_process() anyway, it's probably not worth
getting excited about.
Tom Lane
Robert Haas
Peter Eisentraut
Heikki Linnakangas
Itagaki Takahiro
Magnus Hagander
Teodor Sigaev
Joe Conway