PL/Tcl): SECURITY DEFINER function keyword bypass

The PL/perl and PL/Tcl implementations in PostgreSQL 7.4 before 7.4.30, 8.0 before 8.0.26, 8.1 before 8.1.22, 8.2 before 8.2.18, 8.3 before 8.3.12, 8.4 before 8.4.5, and 9.0 before 9.0.1 do not properly protect script execution by a different SQL user identity within the same session, which allow...