diff options
| author | Tom Lane | 2008-01-03 21:25:34 +0000 |
|---|---|---|
| committer | Tom Lane | 2008-01-03 21:25:34 +0000 |
| commit | 230d5cfc4739bc4963c8d67e4a7cd84abe53ef93 (patch) | |
| tree | 0fa8d138ed251e873bd55a4e7b402fbdd9f57488 /doc/src | |
| parent | 0776cb2116f4eaec743f1e304c1255c318a20d1f (diff) | |
Make standard maintenance operations (including VACUUM, ANALYZE, REINDEX,
and CLUSTER) execute as the table owner rather than the calling user, using
the same privilege-switching mechanism already used for SECURITY DEFINER
functions. The purpose of this change is to ensure that user-defined
functions used in index definitions cannot acquire the privileges of a
superuser account that is performing routine maintenance. While a function
used in an index is supposed to be IMMUTABLE and thus not able to do anything
very interesting, there are several easy ways around that restriction; and
even if we could plug them all, there would remain a risk of reading sensitive
information and broadcasting it through a covert channel such as CPU usage.
To prevent bypassing this security measure, execution of SET SESSION
AUTHORIZATION and SET ROLE is now forbidden within a SECURITY DEFINER context.
Thanks to Itagaki Takahiro for reporting this vulnerability.
Security: CVE-2007-6600
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/ref/set_session_auth.sgml | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/doc/src/sgml/ref/set_session_auth.sgml b/doc/src/sgml/ref/set_session_auth.sgml index 41c88a9f952..b6da266bd65 100644 --- a/doc/src/sgml/ref/set_session_auth.sgml +++ b/doc/src/sgml/ref/set_session_auth.sgml @@ -1,4 +1,4 @@ -<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ref/set_session_auth.sgml,v 1.11 2003/09/11 21:42:20 momjian Exp $ --> +<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ref/set_session_auth.sgml,v 1.11.2.1 2008/01/03 21:25:33 tgl Exp $ --> <refentry id="SQL-SET-SESSION-AUTHORIZATION"> <refmeta> <refentrytitle id="sql-set-session-authorization-title">SET SESSION AUTHORIZATION</refentrytitle> @@ -27,7 +27,7 @@ RESET SESSION AUTHORIZATION <para> This command sets the session user identifier and the current user - identifier of the current SQL-session context to be <replaceable + identifier of the current SQL session to be <replaceable class="parameter">username</replaceable>. The user name may be written as either an identifier or a string literal. Using this command, it is possible, for example, to temporarily become an @@ -38,7 +38,7 @@ RESET SESSION AUTHORIZATION The session user identifier is initially set to be the (possibly authenticated) user name provided by the client. The current user identifier is normally equal to the session user identifier, but - may change temporarily in the context of <quote>setuid</quote> + might change temporarily in the context of <literal>SECURITY DEFINER</> functions and similar mechanisms. The current user identifier is relevant for permission checking. </para> @@ -64,6 +64,15 @@ RESET SESSION AUTHORIZATION </refsect1> <refsect1> + <title>Notes</title> + + <para> + <command>SET SESSION AUTHORIZATION</> cannot be used within a + <literal>SECURITY DEFINER</> function. + </para> + </refsect1> + + <refsect1> <title>Examples</title> <programlisting> |