## E.255. Release 8.1.4

Release date: 2006-05-23

This release contains a variety of fixes from 8.1.3, including patches for extremely serious security issues. For information about new features in the 8.1 major release, see Section E.259.

### E.255.1. Migration to Version 8.1.4

A dump/restore is not required for those running 8.1.X. However, if you are upgrading from a version earlier than 8.1.2, see Section E.257.

Full security against the SQL-injection attacks described in CVE-2006-2313 and CVE-2006-2314 might require changes in application code. If you have applications that embed untrustworthy strings into SQL commands, you should examine them as soon as possible to ensure that they are using recommended escaping techniques. In most cases, applications should be using subroutines provided by libraries or drivers (such as libpq's `PQescapeStringConn()`) to perform string escaping, rather than relying on ad hoc code to do it.

### E.255.2. Changes

- Change the server to reject invalidly-encoded multibyte characters in all cases (Tatsuo, Tom)

  While PostgreSQL has been moving in this direction for some time, the checks are now applied uniformly to all encodings and all textual input, and are now always errors not merely warnings. This change defends against SQL-injection attacks of the type described in CVE-2006-2313.

- Reject unsafe uses of `\'` in string literals

  As a server-side defense against SQL-injection attacks of the type described in CVE-2006-2314, the server now only accepts `''` and not `\'` as a representation of ASCII single quote in SQL string literals. By default, `\'` is rejected only when `client_encoding` is set to a client-only encoding (SJIS, BIG5, GBK, GB18030, or UHC), which is the scenario in which SQL injection is possible. A new configuration parameter `backslash_quote` is available to adjust this behavior when needed. Note that full security against CVE-2006-2314 might require client-side changes; the purpose of `backslash_quote` is in part to make it obvious that insecure clients are insecure.

- Modify libpq's string-escaping routines to be aware of encoding considerations and `standard_conforming_strings`

  This fixes libpq-using applications for the security issues described in CVE-2006-2313 and CVE-2006-2314, and also future-proofs them against the planned changeover to SQL-standard string literal syntax. Applications that use multiple PostgreSQL connections concurrently should migrate to `PQescapeStringConn()` and `PQescapeByteaConn()` to ensure that escaping is done correctly for the settings in use in each database connection. Applications that do string escaping “by hand” should be modified to rely on library routines instead.

- Fix weak key selection in pgcrypto (Marko Kreen)

  Errors in fortuna PRNG reseeding logic could cause a predictable session key to be selected by `pgp_sym_encrypt()` in some cases. This only affects non-OpenSSL-using builds.

- Fix some incorrect encoding conversion functions

  `win1251_to_iso`, `win866_to_iso`, `euc_tw_to_big5`, `euc_tw_to_mic`, `mic_to_euc_tw` were all broken to varying extents.

- Clean up stray remaining uses of `\'` in strings (Bruce, Jan)

- Make autovacuum visible in `pg_stat_activity` (Alvaro)

- Disable `full_page_writes` (Tom)

  In certain cases, having `full_page_writes` off would cause crash recovery to fail. A proper fix will appear in 8.2; for now it's just disabled.

- Various planner fixes, particularly for bitmap index scans and MIN/MAX optimization (Tom)

- Fix incorrect optimization in merge join (Tom)

  Outer joins could sometimes emit multiple copies of unmatched rows.

- Fix crash from using and modifying a plpgsql function in the same transaction

- Fix WAL replay for case where a B-Tree index has been truncated

- Fix `SIMILAR TO` for patterns involving `|` (Tom)

- Fix `SELECT INTO` and `CREATE TABLE AS` to create tables in the default tablespace, not the base directory (Kris Jurka)

- Fix server to use custom DH SSL parameters correctly (Michael Fuhr)

- Improve qsort performance (Dann Corbit)

  Currently this code is only used on Solaris.

- Fix for OS/X Bonjour on x86 systems (Ashley Clark)

- Fix various minor memory leaks

- Fix problem with password prompting on some Win32 systems (Robert Kinberg)

- Improve pg_dump's handling of default values for domains

- Fix pg_dumpall to handle identically-named users and groups reasonably (only possible when dumping from a pre-8.1 server) (Tom)

  The user and group will be merged into a single role with `LOGIN` permission. Formerly the merged role wouldn't have `LOGIN` permission, making it unusable as a user.

- Fix pg_restore `-n` to work as documented (Tom)