Fix bug in SET SESSION AUTHORIZATION that allows unprivileged users to crash

the server, if it has been compiled with Asserts enabled (CVE-2006-0553).
Thanks to Akio Ishida for reporting this problem.

4 files changed, 21 insertions, 10 deletions

diff --git a/src/backend/commands/variable.c b/src/backend/commands/variable.c
index 30173e4cabd..b1d970b9ab0 100644
--- a/src/backend/commands/variable.c
+++ b/src/backend/commands/variable.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/variable.c,v 1.105.4.2 2005/08/08 23:39:14 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/variable.c,v 1.105.4.3 2006/02/12 22:33:14 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -619,7 +619,9 @@ assign_client_encoding(const char *value, bool doit, GucSource source)
  * by the numeric userid, followed by a comma, followed by the user name.
  * This cannot be confused with a plain user name because of the NAMEDATALEN
  * limit on names, so we can tell whether we're being passed an initial
- * username or a saved/restored value.
+ * username or a saved/restored value.  (NOTE: we rely on guc.c to have
+ * properly truncated any incoming value, but not to truncate already-stored
+ * values.  See GUC_IS_NAME processing.)
  */
 extern char *session_authorization_string;		/* in guc.c */
 
diff --git a/src/backend/utils/mb/encnames.c b/src/backend/utils/mb/encnames.c
index 0c28438630b..555231f7c10 100644
--- a/src/backend/utils/mb/encnames.c
+++ b/src/backend/utils/mb/encnames.c
@@ -2,7 +2,7 @@
  * Encoding names and routines for work with it. All
  * in this file is shared bedween FE and BE.
  *
- * $PostgreSQL: pgsql/src/backend/utils/mb/encnames.c,v 1.22 2004/12/04 18:19:31 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/mb/encnames.c,v 1.22.4.1 2006/02/12 22:33:14 tgl Exp $
  */
 #ifdef FRONTEND
 #include "postgres_fe.h"
@@ -434,7 +434,7 @@ pg_char_to_encname_struct(const char *name)
 	if (name == NULL || *name == '\0')
 		return NULL;
 
-	if (strlen(name) > NAMEDATALEN)
+	if (strlen(name) >= NAMEDATALEN)
 	{
 #ifdef FRONTEND
 		fprintf(stderr, "encoding name too long\n");
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index dc4d290ebc3..c1fa6fc5686 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -10,7 +10,7 @@
  * Written by Peter Eisentraut <peter_e@gmx.net>.
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.252.4.2 2005/10/20 20:06:03 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.252.4.3 2006/02/12 22:33:14 tgl Exp $
  *
  *--------------------------------------------------------------------
  */
@@ -44,6 +44,7 @@
 #include "optimizer/prep.h"
 #include "parser/parse_expr.h"
 #include "parser/parse_relation.h"
+#include "parser/scansup.h"
 #include "postmaster/bgwriter.h"
 #include "postmaster/syslogger.h"
 #include "postmaster/postmaster.h"
@@ -1426,7 +1427,7 @@ static struct config_string ConfigureNamesString[] =
 		{"client_encoding", PGC_USERSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets the client's character set encoding."),
 			NULL,
-			GUC_REPORT
+			GUC_IS_NAME | GUC_REPORT
 		},
 		&client_encoding_string,
 		"SQL_ASCII", assign_client_encoding, NULL
@@ -1506,7 +1507,8 @@ static struct config_string ConfigureNamesString[] =
 	{
 		{"default_tablespace", PGC_USERSET, CLIENT_CONN_STATEMENT,
 			gettext_noop("Sets the default tablespace to create tables and indexes in."),
-			gettext_noop("An empty string selects the database's default tablespace.")
+			gettext_noop("An empty string selects the database's default tablespace."),
+		 	GUC_IS_NAME
 		},
 		&default_tablespace,
 		"", assign_default_tablespace, NULL
@@ -1646,7 +1648,7 @@ static struct config_string ConfigureNamesString[] =
 		{"server_encoding", PGC_INTERNAL, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets the server (database) character set encoding."),
 			NULL,
-			GUC_REPORT | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
+			GUC_IS_NAME | GUC_REPORT | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
 		},
 		&server_encoding_string,
 		"SQL_ASCII", NULL, NULL
@@ -1668,7 +1670,7 @@ static struct config_string ConfigureNamesString[] =
 		{"session_authorization", PGC_USERSET, UNGROUPED,
 			gettext_noop("Sets the session user name."),
 			NULL,
-			GUC_REPORT | GUC_NO_SHOW_ALL | GUC_NO_RESET_ALL | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
+			GUC_IS_NAME | GUC_REPORT | GUC_NO_SHOW_ALL | GUC_NO_RESET_ALL | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
 		},
 		&session_authorization_string,
 		NULL, assign_session_authorization, show_session_authorization
@@ -3644,6 +3646,12 @@ set_config_option(const char *name, const char *value,
 					newval = guc_strdup(elevel, value);
 					if (newval == NULL)
 						return false;
+					/*
+					 * The only sort of "parsing" check we need to do is
+					 * apply truncation if GUC_IS_NAME.
+					 */
+					if (conf->gen.flags & GUC_IS_NAME)
+						truncate_identifier(newval, strlen(newval), true);
 				}
 				else if (conf->reset_val)
 				{
diff --git a/src/include/utils/guc_tables.h b/src/include/utils/guc_tables.h
index 39d2af3bab9..4c26e10aaee 100644
--- a/src/include/utils/guc_tables.h
+++ b/src/include/utils/guc_tables.h
@@ -7,7 +7,7 @@
  *
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  *
- *	  $PostgreSQL: pgsql/src/include/utils/guc_tables.h,v 1.19 2004/12/31 22:03:46 pgsql Exp $
+ *	  $PostgreSQL: pgsql/src/include/utils/guc_tables.h,v 1.19.4.1 2006/02/12 22:33:14 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -125,6 +125,7 @@ struct config_generic
 #define GUC_DISALLOW_IN_FILE	0x0040	/* can't set in postgresql.conf */
 #define GUC_CUSTOM_PLACEHOLDER	0x0080	/* placeholder for custom variable */
 #define GUC_SUPERUSER_ONLY		0x0100	/* show only to superusers */
+#define GUC_IS_NAME				0x0200	/* limit string to NAMEDATALEN-1 */
 
 /* bit values in status field */
 #define GUC_HAVE_TENTATIVE	0x0001		/* tentative value is defined */