Release date: 2017-08-10
This release contains a variety of fixes from 9.3.17. For information about new features in the 9.3 major release, see Section E.78.
A dump/restore is not required for those running 9.3.X.
However, if you use foreign data servers that make use of user passwords for authentication, see the first changelog entry below.
Also, if you are upgrading from a version earlier than 9.3.16, see Section E.62.
Further restrict visibility
of pg_user_mappings.umoptions, to
protect passwords stored as user mapping options
(Noah Misch)
The fix for CVE-2017-7486 was incorrect: it allowed a user
to see the options in her own user mapping, even if she did not
have USAGE permission on the associated foreign server.
Such options might include a password that had been provided by the
server owner rather than the user herself.
Since information_schema.user_mapping_options does not
show the options in such cases, pg_user_mappings
should not either.
(CVE-2017-7547)
By itself, this patch will only fix the behavior in newly initdb'd databases. If you wish to apply this change in an existing database, you will need to do the following:
Restart the postmaster after adding allow_system_table_mods
= true to postgresql.conf. (In versions
supporting ALTER SYSTEM, you can use that to make the
configuration change, but you'll still need a restart.)
In each database of the cluster, run the following commands as superuser:
SET search_path = pg_catalog;
CREATE OR REPLACE VIEW pg_user_mappings AS
SELECT
U.oid AS umid,
S.oid AS srvid,
S.srvname AS srvname,
U.umuser AS umuser,
CASE WHEN U.umuser = 0 THEN
'public'
ELSE
A.rolname
END AS usename,
CASE WHEN (U.umuser <> 0 AND A.rolname = current_user
AND (pg_has_role(S.srvowner, 'USAGE')
OR has_server_privilege(S.oid, 'USAGE')))
OR (U.umuser = 0 AND pg_has_role(S.srvowner, 'USAGE'))
OR (SELECT rolsuper FROM pg_authid WHERE rolname = current_user)
THEN U.umoptions
ELSE NULL END AS umoptions
FROM pg_user_mapping U
LEFT JOIN pg_authid A ON (A.oid = U.umuser) JOIN
pg_foreign_server S ON (U.umserver = S.oid);
Do not forget to include the template0
and template1 databases, or the vulnerability will still
exist in databases you create later. To fix template0,
you'll need to temporarily make it accept connections.
In PostgreSQL 9.5 and later, you can use
ALTER DATABASE template0 WITH ALLOW_CONNECTIONS true;
and then after fixing template0, undo that with
ALTER DATABASE template0 WITH ALLOW_CONNECTIONS false;
In prior versions, instead use
UPDATE pg_database SET datallowconn = true WHERE datname = 'template0'; UPDATE pg_database SET datallowconn = false WHERE datname = 'template0';
Finally, remove the allow_system_table_mods configuration
setting, and again restart the postmaster.
Disallow empty passwords in all password-based authentication methods (Heikki Linnakangas)
libpq ignores empty password specifications, and does
not transmit them to the server. So, if a user's password has been
set to the empty string, it's impossible to log in with that password
via psql or other libpq-based
clients. An administrator might therefore believe that setting the
password to empty is equivalent to disabling password login.
However, with a modified or non-libpq-based client,
logging in could be possible, depending on which authentication
method is configured. In particular the most common
method, md5, accepted empty passwords.
Change the server to reject empty passwords in all cases.
(CVE-2017-7546)
Fix concurrent locking of tuple update chains (Álvaro Herrera)
If several sessions concurrently lock a tuple update chain with nonconflicting lock modes using an old snapshot, and they all succeed, it was possible for some of them to nonetheless fail (and conclude there is no live tuple version) due to a race condition. This had consequences such as foreign-key checks failing to see a tuple that definitely exists but is being updated concurrently.
Fix potential data corruption when freezing a tuple whose XMAX is a multixact with exactly one still-interesting member (Teodor Sigaev)
On Windows, retry process creation if we fail to reserve the address range for our shared memory in the new process (Tom Lane, Amit Kapila)
This is expected to fix infrequent child-process-launch failures that are probably due to interference from antivirus products.
Fix low-probability corruption of shared predicate-lock hash table in Windows builds (Thomas Munro, Tom Lane)
Avoid logging clean closure of an SSL connection as though it were a connection reset (Michael Paquier)
Prevent sending SSL session tickets to clients (Tom Lane)
This fix prevents reconnection failures with ticket-aware client-side SSL code.
Fix code for setting tcp_keepalives_idle on Solaris (Tom Lane)
Fix statistics collector to honor inquiry messages issued just after a postmaster shutdown and immediate restart (Tom Lane)
Statistics inquiries issued within half a second of the previous postmaster shutdown were effectively ignored.
Ensure that the statistics collector's receive buffer size is at least 100KB (Tom Lane)
This reduces the risk of dropped statistics data on older platforms whose default receive buffer size is less than that.
Fix possible creation of an invalid WAL segment when a standby is
promoted just after it processes an XLOG_SWITCH WAL
record (Andres Freund)
Fix SIGHUP and SIGUSR1 handling in walsender processes (Petr Jelinek, Andres Freund)
Fix unnecessarily slow restarts of walreceiver processes due to race condition in postmaster (Tom Lane)
Fix cases where an INSERT or UPDATE assigns
to more than one element of a column that is of domain-over-array
type (Tom Lane)
Allow window functions to be used in sub-SELECTs that
are within the arguments of an aggregate function (Tom Lane)
Move autogenerated array types out of the way during
ALTER ... RENAME (Vik Fearing)
Previously, we would rename a conflicting autogenerated array type
out of the way during CREATE; this fix extends that
behavior to renaming operations.
Ensure that ALTER USER ... SET accepts all the syntax
variants that ALTER ROLE ... SET does (Peter Eisentraut)
Properly update dependency info when changing a datatype I/O
function's argument or return type from opaque to the
correct type (Heikki Linnakangas)
CREATE TYPE updates I/O functions declared in this
long-obsolete style, but it forgot to record a dependency on the
type, allowing a subsequent DROP TYPE to leave broken
function definitions behind.
Reduce memory usage when ANALYZE processes
a tsvector column (Heikki Linnakangas)
Fix unnecessary precision loss and sloppy rounding when multiplying
or dividing money values by integers or floats (Tom Lane)
Tighten checks for whitespace in functions that parse identifiers,
such as regprocedurein() (Tom Lane)
Depending on the prevailing locale, these functions could misinterpret fragments of multibyte characters as whitespace.
Use relevant #define symbols from Perl while
compiling PL/Perl (Ashutosh Sharma, Tom Lane)
This avoids portability problems, typically manifesting as a “handshake” mismatch during library load, when working with recent Perl versions.
In libpq, reset GSS/SASL and SSPI authentication state properly after a failed connection attempt (Michael Paquier)
Failure to do this meant that when falling back from SSL to non-SSL connections, a GSS/SASL failure in the SSL attempt would always cause the non-SSL attempt to fail. SSPI did not fail, but it leaked memory.
In psql, fix failure when COPY FROM STDIN
is ended with a keyboard EOF signal and then another COPY
FROM STDIN is attempted (Thomas Munro)
This misbehavior was observed on BSD-derived platforms (including macOS), but not on most others.
Fix pg_dump and pg_restore to
emit REFRESH MATERIALIZED VIEW commands last (Tom Lane)
This prevents errors during dump/restore when a materialized view refers to tables owned by a different user.
Fix pg_dump with the --clean option to
drop event triggers as expected (Tom Lane)
It also now correctly assigns ownership of event triggers; before, they were restored as being owned by the superuser running the restore script.
Fix pg_dump to not emit invalid SQL for an empty operator class (Daniel Gustafsson)
Fix pg_dump output to stdout on Windows (Kuntal Ghosh)
A compressed plain-text dump written to stdout would contain corrupt data due to failure to put the file descriptor into binary mode.
Fix pg_get_ruledef() to print correct output for
the ON SELECT rule of a view whose columns have been
renamed (Tom Lane)
In some corner cases, pg_dump relies
on pg_get_ruledef() to dump views, so that this error
could result in dump/reload failures.
Fix dumping of outer joins with empty constraints, such as the result
of a NATURAL LEFT JOIN with no common columns (Tom Lane)
Fix dumping of function expressions in the FROM clause in
cases where the expression does not deparse into something that looks
like a function call (Tom Lane)
Fix pg_basebackup output to stdout on Windows (Haribabu Kommi)
A backup written to stdout would contain corrupt data due to failure to put the file descriptor into binary mode.
Fix pg_upgrade to ensure that the ending WAL record
does not have wal_level = minimum
(Bruce Momjian)
This condition could prevent upgraded standby servers from reconnecting.
In postgres_fdw, re-establish connections to remote
servers after ALTER SERVER or ALTER USER
MAPPING commands (Kyotaro Horiguchi)
This ensures that option changes affecting connection parameters will be applied promptly.
In postgres_fdw, allow cancellation of remote
transaction control commands (Robert Haas, Rafia Sabih)
This change allows us to quickly escape a wait for an unresponsive remote server in many more cases than previously.
Always use -fPIC, not -fpic, when building
shared libraries with gcc (Tom Lane)
This supports larger extension libraries on platforms where it makes a difference.
Fix unescaped-braces issue in our build scripts for Microsoft MSVC, to avoid a warning or error from recent Perl versions (Andrew Dunstan)
In MSVC builds, handle the case where the OpenSSL
library is not within a VC subdirectory (Andrew Dunstan)
In MSVC builds, add proper include path for libxml2 header files (Andrew Dunstan)
This fixes a former need to move things around in standard Windows installations of libxml2.
In MSVC builds, recognize a Tcl library that is
named tcl86.lib (Noah Misch)