PostgreSQL 8.4.7 Documentation
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# E.38. Release 8.2.6

> Release date: 2008-01-07

This release contains a variety of fixes from 8.2.5, including fixes for significant security issues. For information about new features in the 8.2 major release, see Section E.44.

## E.38.1. Migration to Version 8.2.6

A dump/restore is not required for those running 8.2.X.

## E.38.2. Changes

- Prevent functions in indexes from executing with the privileges of the user running `VACUUM`, `ANALYZE`, etc (Tom)

  Functions used in index expressions and partial-index predicates are evaluated whenever a new table entry is made. It has long been understood that this poses a risk of trojan-horse code execution if one modifies a table owned by an untrustworthy user. (Note that triggers, defaults, check constraints, etc. pose the same type of risk.) But functions in indexes pose extra danger because they will be executed by routine maintenance operations such as `VACUUM FULL`, which are commonly performed automatically under a superuser account. For example, a nefarious user can execute code with superuser privileges by setting up a trojan-horse index definition and waiting for the next routine vacuum. The fix arranges for standard maintenance operations (including `VACUUM`, `ANALYZE`, `REINDEX`, and `CLUSTER`) to execute as the table owner rather than the calling user, using the same privilege-switching mechanism already used for `SECURITY DEFINER` functions. To prevent bypassing this security measure, execution of `SET SESSION AUTHORIZATION` and `SET ROLE` is now forbidden within a `SECURITY DEFINER` context. (CVE-2007-6600)

- Repair assorted bugs in the regular-expression package (Tom, Will Drewry)

  Suitably crafted regular-expression patterns could cause crashes, infinite or near-infinite looping, and/or massive memory consumption, all of which pose denial-of-service hazards for applications that accept regex search patterns from untrustworthy sources. (CVE-2007-4769, CVE-2007-4772, CVE-2007-6067)

- Require non-superusers who use `/contrib/dblink` to use only password authentication, as a security measure (Joe)

  The fix that appeared for this in 8.2.5 was incomplete, as it plugged the hole for only some `dblink` functions. (CVE-2007-6601, CVE-2007-3278)

- Fix bugs in WAL replay for GIN indexes (Teodor)

- Fix GIN index build to work properly when `maintenance_work_mem` is 4GB or more (Tom)

- Update time zone data files to tzdata release 2007k (in particular, recent Argentina changes) (Tom)

- Improve planner's handling of LIKE/regex estimation in non-C locales (Tom)

- Fix planning-speed problem for deep outer-join nests, as well as possible poor choice of join order (Tom)

- Fix planner failure in some cases of `WHERE false AND var IN (SELECT ...)` (Tom)

- Make `CREATE TABLE ... SERIAL` and `ALTER SEQUENCE ... OWNED BY` not change the `currval()` state of the sequence (Tom)

- Preserve the tablespace and storage parameters of indexes that are rebuilt by `ALTER TABLE ... ALTER COLUMN TYPE` (Tom)

- Make archive recovery always start a new WAL timeline, rather than only when a recovery stop time was used (Simon)

  This avoids a corner-case risk of trying to overwrite an existing archived copy of the last WAL segment, and seems simpler and cleaner than the original definition.

- Make `VACUUM` not use all of `maintenance_work_mem` when the table is too small for it to be useful (Alvaro)

- Fix potential crash in `translate()` when using a multibyte database encoding (Tom)

- Make `corr()` return the correct result for negative correlation values (Neil)

- Fix overflow in `extract(epoch from interval)` for intervals exceeding 68 years (Tom)

- Fix PL/Perl to not fail when a UTF-8 regular expression is used in a trusted function (Andrew)

- Fix PL/Perl to cope when platform's Perl defines type `bool` as `int` rather than `char` (Tom)

  While this could theoretically happen anywhere, no standard build of Perl did things this way ... until Mac OS X 10.5.

- Fix PL/Python to work correctly with Python 2.5 on 64-bit machines (Marko Kreen)

- Fix PL/Python to not crash on long exception messages (Alvaro)

- Fix pg_dump to correctly handle inheritance child tables that have default expressions different from their parent's (Tom)

- Fix libpq crash when `PGPASSFILE` refers to a file that is not a plain file (Martin Pitt)

- ecpg parser fixes (Michael)

- Make `contrib/pgcrypto` defend against OpenSSL libraries that fail on keys longer than 128 bits; which is the case at least on some Solaris versions (Marko Kreen)

- Make `contrib/tablefunc`'s `crosstab()` handle NULL rowid as a category in its own right, rather than crashing (Joe)

- Fix `tsvector` and `tsquery` output routines to escape backslashes correctly (Teodor, Bruce)

- Fix crash of `to_tsvector()` on huge input strings (Teodor)

- Require a specific version of Autoconf to be used when re-generating the `configure` script (Peter)

  This affects developers and packagers only. The change was made to prevent accidental use of untested combinations of Autoconf and PostgreSQL versions. You can remove the version check if you really want to use a different Autoconf version, but it's your responsibility whether the result works or not.

- Update `gettimeofday` configuration check so that PostgreSQL can be built on newer versions of MinGW (Magnus)

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