File postgresql-SECURITY-NOTICE of Package postgresql

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File postgresql-SECURITY-NOTICE of Package postgresql

Q: What's being released?
A: PostgreSQL minor versions 8.1.4, 8.0.8, 7.4.13 and 7.3.15. All of
   these versions implement a security patch which eliminates a
   specific vulnerability to SQL injection attacks.

Q: Who does this vulnerability affect?
A: Users of PostgreSQL servers which are exposed to "untrusted input",
   from the internet or otherwise, and use any "multi-byte encoding",
   such as UTF-8 or SJIS. Basically, most open source database users
   with Web applications.

Q: Who is not affected?
A: Several kinds of applications:

1. Users whose database applications are not exposed to untrusted
      input, such as single-user applications not exposed to the
      Internet.
   2. Databases which are set up with "LATIN-1" or other single-byte
      encoding, on both client and server.
   3. If application always sends untrusted strings as out-of-line
      parameters, instead of embedding them into SQL commands, it is
      not vulnerable. This is only available in PostgreSQL 7.4 or
      later.

Q: Is anyone in particular danger?
A: Applications using Far East encodings (SJIS, BIG5, GBK, GB18030,
   and UHC) which use ad-hoc methods to "escape" strings going into
   the database, such as regexes, or PHP3's addslashes() and
   magic_quotes. Since these bypass database-specific code for safe
   handling of strings, many such applications will need to be
   re-written to become secure. (Note that the PHP team deprecated
   addslashes() and magic_quotes in version 4.0 because of the
   security risk. Unfortunately, it still appears in a distressing
   number of freeware PHP applications online.)

Q: When will updates be available?
A: Source packages are available now, as well as binary packages for
   Windows, Red Hat Linux and a few other operating systems. Updates
   for PostgreSQL drivers for most programming languages will be
   available by Wednesday, with others to follow in less than a week.

Q: What should users do?
A: Three steps:

1. Read the full release notes on the new patches;
   2. Update their database servers and their database drivers;
   3. Remove any non-standard string escaping mechanisms from their
      applications, such as the popular "backslash-escape", or "\'",
      or at least modify them to use the SQL-standard doubling ('') to
      escape quotes.

Q: Ouch! Step #3 looks painful. Do I really need to refactor my
   application?
A: Only if you are using a Far Eastern multi-byte encoding (SJIS,
   BIG5, GBK, GB18030, and UHC). If you are using UTF-8, then applying
   the new version of PostgreSQL is sufficient. Of course, you should
   plan to migrate your application to use proper escaping functions
   when you can, so that it won't break when PostgreSQL transitions to
   SQL-standard strings (which don't have backslash
   escapes). SQL-standard strings will become the default soon,
   perhaps as soon as PostgreSQL 8.3.

Q: What else can I do to foil SQL injection attacks?
A: There are quite a number of steps you can use to foil SQL injection
   attacks in addition to these updates, which are things
   security-conscious application developers should be doing anyway:

1. Employ a good database security design, in which restrictive
      database permissions are assigned to public database roles.
   2. Use parameterized prepared statements to execute queries
      (e.g. "SELECT * FROM table WHERE id = ?") (please note that PHP
      does not have proper support for this feature earlier than v5.1)
   3. Use stored procedures to execute queries from web applications,
      instead of sending them directly to the database.
   4. Hash or encrypt valuable data in the database.

Q: What if I'm using PostgreSQL 7.2 or 7.1?
A: Then you should have upgraded two years ago. PostgreSQL 7.2 has
   been out-of-maintenance since 2004. Please upgrade to a more
   current version as soon as you can.

Q: Why did you release a security update which breaks my application?
A: Believe us, we tried not to. Six PostgreSQL programmers worked for
   four weeks to come up with a method to fix the vulnerability
   without affecting production applications. This was the best we
   could do -- it leaves most users' applications untouched.

Q: What if my application is not exposed to the internet, and I want
   to upgrade but disable the escaping changes?
A: Set "backslash_quote = on" in postgresql.conf. And make plans to
   secure your application at a more convenient time.

Q: You say PHP hackers shouldn't use addslashes() or magic_quotes_gpc.
   What should they use?
A: Any of the following:

1. pg_escape_string() (but look for a driver update soon)
   2. PEAR-DB or PEAR-MDB2
   3. PDO
   4. If you're using magic_quotes_gpc, test using magic_quotes_sybase
      instead.

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