Ensure that pg_saslprep() initializes its output argument to NULL in
all failure paths, and then remove the redundant initialization that
some (not all) of its callers did. This does not fix any live bug,
but it reduces the odds of future bugs of omission.
Also add a comment about why the existing failure-path coding is
adequate.
Back-patch so as to keep the function's API consistent across branches,
again to forestall future bug introduction.
Patch by me, reviewed by Michael Paquier
Discussion: https://postgr.es/m/16558.1536407783@sss.pgh.pa.us
Commits c6b3c939b (which fixed the precedence of >=, <=, <> operators)
and 865f14a2d (which added support for the standard => notation for
named arguments) created a class of lexer tokens which look like
multi-character operators but which have their own token IDs distinct
from Op. However, longest-match rules meant that following any of
these tokens with another operator character, as in (1<>-1), would
cause them to be incorrectly returned as Op.
The error here isn't immediately obvious, because the parser would
usually still find the correct operator via the Op token, but there
were more subtle problems:
1. If immediately followed by a comment or +-, >= <= <> would be given
the old precedence of Op rather than the correct new precedence;
2. If followed by a comment, != would be returned as Op rather than as
NOT_EQUAL, causing it not to be found at all;
3. If followed by a comment or +-, the => token for named arguments
would be lexed as Op, causing the argument to be mis-parsed as a
simple expression, usually causing an error.
Fix by explicitly checking for the operators in the {operator} code
block in addition to all the existing special cases there.
Backpatch to 9.5 where the problem was introduced.
Analysis and patch by me; review by Tom Lane.
Discussion: https://postgr.es/m/87va851ppl.fsf@news-spur.riddles.org.uk
The lexer's handling of operators contained an O(N^3) hazard when
dealing with long strings of + or - characters; it seems hard to
prevent this case from being O(N^2), but the additional N multiplier
was not needed.
Backpatch all the way since this has been there since 7.x, and it
presents at least a mild hazard in that trying to do Bind, PREPARE or
EXPLAIN on a hostile query could take excessive time (without
honouring cancels or timeouts) even if the query was never executed.
Historically, we looked up the target hostname in connectDBStart, so that
PQconnectPoll did not need to do DNS name resolution. The patches that
added multiple-target-host support to libpq preserved this division of
labor; but it's really nonsensical now, because it means that if any one
of the target hosts fails to resolve in DNS, the connection fails. That
negates the no-single-point-of-failure goal of the feature. Additionally,
DNS lookups aren't exactly cheap, but the code did them all even if the
first connection attempt succeeds.
Hence, rearrange so that PQconnectPoll does the lookups, and only looks
up a hostname when it's time to try that host. This does mean that
PQconnectPoll could block on a DNS lookup --- but if you wanted to avoid
that, you should be using hostaddr, as the documentation has always
specified. It seems fairly unlikely that any applications would really
care whether the lookup occurs inside PQconnectStart or PQconnectPoll.
In addition to calling out that fact explicitly, do some other minor
wordsmithing in the docs around the multiple-target-host feature.
Since this seems like a bug in the multiple-target-host feature,
backpatch to v10 where that was introduced. In the back branches,
avoid moving any existing fields of struct pg_conn, just in case
any third-party code is looking into that struct.
Tom Lane, reviewed by Fabien Coelho
Discussion: https://postgr.es/m/4913.1533827102@sss.pgh.pa.us
Fix a small number of places that were testing the result of snprintf()
but doing so incorrectly. The right test for buffer overrun, per C99,
is "result >= bufsize" not "result > bufsize". Some places were also
checking for failure with "result == -1", but the standard only says
that a negative value is delivered on failure.
(Note that this only makes these places correct if snprintf() delivers
C99-compliant results. But at least now these places are consistent
with all the other places where we assume that.)
Also, make psql_start_test() and isolation_start_test() check for
buffer overrun while constructing their shell commands. There seems
like a higher risk of overrun, with more severe consequences, here
than there is for the individual file paths that are made elsewhere
in the same functions, so this seemed like a worthwhile change.
Also fix guc.c's do_serialize() to initialize errno = 0 before
calling vsnprintf. In principle, this should be unnecessary because
vsnprintf should have set errno if it returns a failure indication ...
but the other two places this coding pattern is cribbed from don't
assume that, so let's be consistent.
These errors are all very old, so back-patch as appropriate. I think
that only the shell command overrun cases are even theoretically
reachable in practice, but there's not much point in erroneous error
checks.
Discussion: https://postgr.es/m/17245.1534289329@sss.pgh.pa.us
Commit 5f374fe7a attempted to turn the connect_timeout from an overall
maximum time limit into a per-host limit, but it didn't do a great job of
that. The timer would only get restarted if we actually detected timeout
within connectDBComplete(), not if we changed our attention to a new host
for some other reason. In that case the old timeout continued to run,
possibly causing a premature timeout failure for the new host.
Fix that, and also tweak the logic so that if we do get a timeout,
we advance to the next available IP address, not to the next host name.
There doesn't seem to be a good reason to assume that all the IP
addresses supplied for a given host name will necessarily fail the
same way as the current one. Moreover, this conforms better to the
admittedly-vague documentation statement that the timeout is "per
connection attempt". I changed that to "per host name or IP address"
to be clearer. (Note that reconnections to the same server, such as for
switching protocol version or SSL status, don't get their own separate
timeout; that was true before and remains so.)
Also clarify documentation about the interpretation of connect_timeout
values less than 2.
This seems like a bug, so back-patch to v10 where this logic came in.
Tom Lane, reviewed by Fabien Coelho
Discussion: https://postgr.es/m/5735.1533828184@sss.pgh.pa.us
The logic in PQconnectPoll() did not take care to ensure that all of
a PGconn's internal state variables were reset before trying a new
connection attempt. If we got far enough in the connection sequence
to have changed any of these variables, and then decided to try a new
server address or server name, the new connection might be completed
with some state that really only applied to the failed connection.
While this has assorted bad consequences, the only one that is clearly
a security issue is that password_needed didn't get reset, so that
if the first server asked for a password and the second didn't,
PQconnectionUsedPassword() would return an incorrect result. This
could be leveraged by unprivileged users of dblink or postgres_fdw
to allow them to use server-side login credentials that they should
not be able to use.
Other notable problems include the possibility of forcing a v2-protocol
connection to a server capable of supporting v3, or overriding
"sslmode=prefer" to cause a non-encrypted connection to a server that
would have accepted an encrypted one. Those are certainly bugs but
it's harder to paint them as security problems in themselves. However,
forcing a v2-protocol connection could result in libpq having a wrong
idea of the server's standard_conforming_strings setting, which opens
the door to SQL-injection attacks. The extent to which that's actually
a problem, given the prerequisite that the attacker needs control of
the client's connection parameters, is unclear.
These problems have existed for a long time, but became more easily
exploitable in v10, both because it introduced easy ways to force libpq
to abandon a connection attempt at a late stage and then try another one
(rather than just giving up), and because it provided an easy way to
specify multiple target hosts.
Fix by rearranging PQconnectPoll's state machine to provide centralized
places to reset state properly when moving to a new target host or when
dropping and retrying a connection to the same host.
Tom Lane, reviewed by Noah Misch. Our thanks to Andrew Krasichkov
for finding and reporting the problem.
Security: CVE-2018-10915
Commit 1944cdc98 changed PQhost() to return the hostaddr value when that
is specified and host isn't. This is a good idea in general, but
fe-auth.c and related files contain PQhost() calls for which it isn't.
Specifically, when we compare SSL certificates or other server identity
information to the host field, we do not want to use hostaddr instead;
that's not what's documented, that's not what happened pre-v10, and
it doesn't seem like a good idea.
Instead, we can just look at connhost[].host directly. This does what
we want in v10 and up; in particular, if neither host nor hostaddr
were given, the host field will be replaced with the default host name.
That seems useful, and it's likely the reason that these places were
coded to call PQhost() originally (since pre-v10, the stored field was
not replaced with the default).
Back-patch to v10, as 1944cdc98 (just) was.
Discussion: https://postgr.es/m/23287.1533227021@sss.pgh.pa.us
Previously, PQhost didn't return the connected host details when the
connection type was CHT_HOST_ADDRESS (i.e., via hostaddr). Instead, it
returned the complete host connection parameter (which could contain
multiple hosts) or the default host details, which was confusing and
arguably incorrect.
Change this to return the actually connected host or hostaddr
irrespective of the connection type. When hostaddr but no host was
specified, hostaddr is now returned. Never return the original host
connection parameter, and document that PQhost cannot be relied on
before the connection is established.
PQport is similarly changed to always return the active connection port
and never the original connection parameter.
Back-patch of commit 1944cdc982
into the v10 branch.
Author: Hari Babu <kommi.haribabu@gmail.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>
Reviewed-by: David G. Johnston <david.g.johnston@gmail.com>
Before v10, we always searched ~/.pgpass using the host parameter,
and nothing else, to match to the "hostname" field of ~/.pgpass.
(However, null host or host matching DEFAULT_PGSOCKET_DIR was replaced by
"localhost".) In v10, this got broken by commit 274bb2b38, repaired by
commit bdac9836d, and broken again by commit 7b02ba62e; in the code
actually shipped, we'd search with hostaddr if both that and host were
specified --- though oddly, *not* if only hostaddr were specified.
Since this is directly contrary to the documentation, and not
backwards-compatible, it's clearly a bug.
However, the change wasn't totally without justification, even though it
wasn't done quite right, because the pre-v10 behavior has arguably been
buggy since we added hostaddr. If hostaddr is specified and host isn't,
the pre-v10 code will search ~/.pgpass for "localhost", and ship that
password off to a server that most likely isn't local at all. That's
unhelpful at best, and could be a security breach at worst.
Therefore, rather than just revert to that old behavior, let's define
the behavior as "search with host if provided, else with hostaddr if
provided, else search for localhost". (As before, a host name matching
DEFAULT_PGSOCKET_DIR is replaced by localhost.) This matches the
behavior of the actual connection code, so that we don't pick up an
inappropriate password; and it allows useful searches to happen when
only hostaddr is given.
While we're messing around here, ensure that empty elements within a
host or hostaddr list select the same behavior as a totally-empty
field would; for instance "host=a,,b" is equivalent to "host=a,/tmp,b"
if DEFAULT_PGSOCKET_DIR is /tmp. Things worked that way in some cases
already, but not consistently so, which contributed to the confusion
about what key ~/.pgpass would get searched with.
Update documentation accordingly, and also clarify some nearby text.
Back-patch to v10 where the host/hostaddr list functionality was
introduced.
Discussion: https://postgr.es/m/30805.1532749137@sss.pgh.pa.us
A collection of typos I happened to spot while reading code, as well as
grepping for common mistakes.
Backpatch to all supported versions, as applicable, to avoid conflicts
when backporting other commits in the future.
Back-patch commit dddfc4cb2, which broke LDFLAGS and related Makefile
variables into two parts, one for within-build-tree library references and
one for external libraries, to ensure that the order of -L flags has all
of the former before all of the latter. This turns out to fix a problem
recently noted on buildfarm member peripatus, that we attempted to
incorporate code from libpgport.a into a shared library. That will fail on
platforms that are sticky about putting non-PIC code into shared libraries.
(It's quite surprising we hadn't seen such failures before, since the code
in question has been like that for a long time.)
I think that peripatus' problem could have been fixed with just a subset
of this patch; but since the previous issue of accidentally linking to the
wrong copy of a Postgres shlib seems likely to bite people in the field,
let's just back-patch the whole change. Now that commit dddfc4cb2 has
survived some beta testing, I'm less afraid to back-patch it than I was
at the time.
This also fixes undesired inclusion of "-DFRONTEND" in pg_config's CPPFLAGS
output (in 9.6 and up) and undesired inclusion of "-L../../src/common" in
its LDFLAGS output (in all supported branches).
Back-patch to v10 and older branches; this is already in v11.
Discussion: https://postgr.es/m/20180704234304.bq2dxispefl65odz@ler-imac.local
On Windows, it is sometimes important for corresponding malloc() and
free() calls to be made from the same DLL, since some build options can
result in multiple allocators being active at the same time. For that
reason we already provided PQfreemem(). This commit adds a similar
function for freeing string results allocated by the pgtypes library.
Author: Takayuki Tsunakawa
Reviewed-by: Kyotaro Horiguchi
Discussion: https://postgr.es/m/0A3221C70F24FB45833433255569204D1F8AD5D6%40G01JPEXMBYT05
Use of strncpy with a length limit based on the source, rather than
the destination, is non-idiomatic and draws warnings from gcc 8.
Replace with memcpy, which does exactly the same thing in these cases,
but with less chance for confusion.
Backpatch to all supported branches.
Discussion: https://postgr.es/m/21789.1529170195@sss.pgh.pa.us
The "l" (ell) width spec means something in the corresponding scanf usage,
but not here. While modern POSIX says that applying "l" to "f" and other
floating format specs is a no-op, SUSv2 says it's undefined. Buildfarm
experience says that some old compilers emit warnings about it, and at
least one old stdio implementation (mingw's "ANSI" option) actually
produces wrong answers and/or crashes.
Discussion: https://postgr.es/m/21670.1526769114@sss.pgh.pa.us
Discussion: https://postgr.es/m/c085e1da-0d64-1c15-242d-c921f32e0d5c@dunslane.net
This will only actually exercise the "long long" code paths on platforms
where "long" is 32 bits --- otherwise, the SQL bigint type maps to
plain "long", and we will test that code path instead. But that's
probably sufficient coverage, and anyway we weren't testing either
code path before.
Dang Minh Huong, tweaked a bit by me
Discussion: https://postgr.es/m/151935568942.1461.14623890240535309745@wrigleys.postgresql.org
We'd throw away the partial result anyway after parsing the error message.
Throwing it away beforehand costs nothing and reduces the risk of
out-of-memory failure. Also, at least in systems that behave like
glibc/Linux, if the partial result was very large then the error PGresult
would get allocated at high heap addresses, preventing the heap storage
used by the partial result from being released to the OS until the error
PGresult is freed.
In psql >= 9.6, we hold onto the error PGresult until another error is
received (for \errverbose), so that this behavior causes a seeming
memory leak to persist for awhile, as in a recent complaint from
Darafei Praliaskouski. This is a potential performance regression from
older versions, justifying back-patching at least that far. But similar
behavior may occur in other client applications, so it seems worth just
back-patching to all supported branches.
Discussion: https://postgr.es/m/CAC8Q8tJ=7cOkPePyAbJE_Pf691t8nDFhJp0KZxHvnq_uicfyVg@mail.gmail.com
For years, our makefiles have correctly observed that "there is no correct
way to write a rule that generates two files". However, what we did is to
provide empty rules that "generate" the secondary output files from the
primary one, and that's not right either. Depending on the details of
the creating process, the primary file might end up timestamped later than
one or more secondary files, causing subsequent make runs to consider the
secondary file(s) out of date. That's harmless in a plain build, since
make will just re-execute the empty rule and nothing happens. But it's
fatal in a VPATH build, since make will expect the secondary file to be
rebuilt in the build directory. This would manifest as "file not found"
failures during VPATH builds from tarballs, if we were ever unlucky enough
to ship a tarball with apparently out-of-date secondary files. (It's not
clear whether that has ever actually happened, but it definitely could.)
To ensure that secondary output files have timestamps >= their primary's,
change our makefile convention to be that we provide a "touch $@" action
not an empty rule. Also, make sure that this rule actually gets invoked
during a distprep run, else the hazard remains.
It's been like this a long time, so back-patch to all supported branches.
In HEAD, I skipped the changes in src/backend/catalog/Makefile, because
those rules are due to get replaced soon in the bootstrap data format
patch, and there seems no need to create a merge issue for that patch.
If for some reason we fail to land that patch in v11, we'll need to
back-fill the changes in that one makefile from v10.
Discussion: https://postgr.es/m/18556.1521668179@sss.pgh.pa.us
pg_hba_file_rules erroneously reported this as scram-sha256. Fix that.
To avoid future errors and confusion, also adjust documentation links
and internal symbols to have a separator between "sha" and "256".
Reported-by: Christophe Courtois <christophe.courtois@dalibo.com>
Author: Michael Paquier <michael.paquier@gmail.com>
This suite had been a proper superset of the regular ecpg test suite,
but the three newest tests didn't reach it. To make this less likely to
recur, delete the extra schedule file and pass the TCP-specific test on
the command line. Back-patch to 9.3 (all supported versions).
Since commit 868898739a, it has assumed
"localhost" resolves to both ::1 and 127.0.0.1. We gain nothing from
that assumption, and it does not hold in a default installation of Red
Hat Enterprise Linux 5. Back-patch to 9.3 (all supported versions).
isdigit(), isspace(), etc are likely to give surprising results if passed a
signed char. We should always cast the argument to unsigned char to avoid
that. Error in commit 63d6b97fd, found by buildfarm member gaur.
Back-patch to 9.3, like that commit.
Makefile.global assigns this prerequisite to every target named "check",
but similar targets must mention it explicitly. Affected targets
failed, tested $PATH binaries, or tested a stale temporary installation.
The src/test/modules examples worked properly when called as "make -C
src/test/modules/$FOO check", but "make -j" allowed the test to start
before the temporary installation was in place. Back-patch to 9.5,
where commit dcae5facca introduced the
shared temp-install.
Some people like to run libpq-using applications in environments where
there's no home directory. We've broken that scenario before (cf commits
5b4067798 and bd58d9d88), and commit ba005f193 broke it again, by making
it a hard error if we fail to get the home directory name while looking
for ~/.pgpass. The previous precedent is that if we can't get the home
directory name, we should just silently act as though the file we hoped
to find there doesn't exist. Rearrange the new code to honor that.
Looking around, the service-file code added by commit 41a4e4595 had the
same disease. Apparently, that escaped notice because it only runs when
a service name has been specified, which I guess the people who use this
scenario don't do. Nonetheless, it's wrong too, so fix that case as well.
Add a comment about this policy to pqGetHomeDirectory, in the probably
vain hope of forestalling the same error in future. And upgrade the
rather miserable commenting in parseServiceInfo, too.
In passing, also back off parseServiceInfo's assumption that only ENOENT
is an ignorable error from stat() when checking a service file. We would
need to ignore at least ENOTDIR as well (cf 5b4067798), and seeing that
the far-better-tested code for ~/.pgpass treats all stat() failures alike,
I think this code ought to as well.
Per bug #14872 from Dan Watson. Back-patch the .pgpass change to v10
where ba005f193 came in. The service-file bugs are far older, so
back-patch the other changes to all supported branches.
Discussion: https://postgr.es/m/20171025200457.1471.34504@wrigleys.postgresql.org
Adding more than 1 billion rows to a PGresult would overflow its ntups and
tupArrSize fields, leading to client crashes. It'd be desirable to use
wider fields on 64-bit machines, but because all of libpq's external APIs
use plain "int" for row counters, that's going to be hard to accomplish
without an ABI break. Given the lack of complaints so far, and the general
pain that would be involved in using such huge PGresults, let's settle for
just preventing the overflow and reporting a useful error message if it
does happen. Also, for a couple more lines of code we can increase the
threshold of trouble from INT_MAX/2 to INT_MAX rows.
To do that, refactor pqAddTuple() to allow returning an error message that
replaces the default assumption that it failed because of out-of-memory.
Along the way, fix PQsetvalue() so that it reports all failures via
pqInternalNotice(). It already did so in the case of bad field number,
but neglected to report anything for other error causes.
Because of the potential for crashes, this seems like a back-patchable
bug fix, despite the lack of field reports.
Michael Paquier, per a complaint from Igor Korot.
Discussion: https://postgr.es/m/CA+FnnTxyLWyjY1goewmJNxC==HQCCF4fKkoCTa9qR36oRAHDPw@mail.gmail.com
