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

1 files changed, 4 insertions, 3 deletions

diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 1dbd737db3b..7f7894b597a 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -12,7 +12,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: miscadmin.h,v 1.111 2002/10/03 17:07:53 momjian Exp $
+ * $Id: miscadmin.h,v 1.111.2.1 2008/01/03 21:25:58 tgl Exp $
  *
  * NOTES
  *	  some of the information in this file should be moved to
@@ -203,9 +203,10 @@ extern void SetDatabasePath(const char *path);
 extern char *GetUserNameFromId(Oid userid);
 
 extern Oid	GetUserId(void);
-extern void SetUserId(Oid userid);
 extern Oid	GetSessionUserId(void);
-extern void SetSessionUserId(Oid userid);
+extern void GetUserIdAndContext(Oid *userid, bool *sec_def_context);
+extern void SetUserIdAndContext(Oid userid, bool sec_def_context);
+extern bool InSecurityDefinerContext(void);
 extern void InitializeSessionUserId(const char *username);
 extern void InitializeSessionUserIdStandalone(void);
 extern void SetSessionAuthorization(Oid userid);