Restrict accesses to non-system views and foreign tables during pg_dump.

When pg_dump retrieves the list of database objects and performs the
data dump, there was possibility that objects are replaced with others
of the same name, such as views, and access them. This vulnerability
could result in code execution with superuser privileges during the
pg_dump process.

This issue can arise when dumping data of sequences, foreign
tables (only 13 or later), or tables registered with a WHERE clause in
the extension configuration table.

To address this, pg_dump now utilizes the newly introduced
restrict_nonsystem_relation_kind GUC parameter to restrict the
accesses to non-system views and foreign tables during the dump
process. This new GUC parameter is added to back branches too, but
these changes do not require cluster recreation.

Back-patch to all supported branches.

Reviewed-by: Noah Misch
Security: CVE-2024-7348
Backpatch-through: 12

diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index 811a68b3ec3504dc2c5b3cbdee651c5c17941af7..063869c2ad5bbb8d22976e295e8390052dddcfc3 100644 (file)
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -637,6 +637,17 @@ EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft_empty ORDER BY c1;
    Remote SQL: SELECT c1, c2 FROM public.loct_empty ORDER BY c1 ASC NULLS LAST
 (3 rows)
 
+-- test restriction on non-system foreign tables.
+SET restrict_nonsystem_relation_kind TO 'foreign-table';
+SELECT * from ft1 where c1 < 1; -- ERROR
+ERROR:  access to non-system foreign table is restricted
+INSERT INTO ft1 (c1) VALUES (1); -- ERROR
+ERROR:  access to non-system foreign table is restricted
+DELETE FROM ft1 WHERE c1 = 1; -- ERROR
+ERROR:  access to non-system foreign table is restricted
+TRUNCATE ft1; -- ERROR
+ERROR:  access to non-system foreign table is restricted
+RESET restrict_nonsystem_relation_kind;
 -- ===================================================================
 -- WHERE with remotely-executable conditions
 -- ===================================================================

diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 8be9f99c192253c849e27ddca8d0e2c419316555..db69434188581a60d2beffc72953ff6abfc34320 100644 (file)
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -327,6 +327,14 @@ DELETE FROM loct_empty;
 ANALYZE ft_empty;
 EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft_empty ORDER BY c1;
 
+-- test restriction on non-system foreign tables.
+SET restrict_nonsystem_relation_kind TO 'foreign-table';
+SELECT * from ft1 where c1 < 1; -- ERROR
+INSERT INTO ft1 (c1) VALUES (1); -- ERROR
+DELETE FROM ft1 WHERE c1 = 1; -- ERROR
+TRUNCATE ft1; -- ERROR
+RESET restrict_nonsystem_relation_kind;
+
 -- ===================================================================
 -- WHERE with remotely-executable conditions
 -- ===================================================================

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index d35b82a582c54299a6bc49ac2958ce4de263f490..d778d28e6f6372ba11e77452d917d818c767b48a 100644 (file)
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -9813,6 +9813,23 @@ SET XML OPTION { DOCUMENT | CONTENT };
      </listitem>
      </varlistentry>
 
+     <varlistentry id="guc-restrict-nonsystem-relation-kind" xreflabel="restrict_nonsystem_relation_kind">
+      <term><varname>restrict_nonsystem_relation_kind</varname> (<type>string</type>)
+      <indexterm>
+       <primary><varname>restrict_nonsystem_relation_kind</varname></primary>
+       <secondary>configuration parameter</secondary>
+     </indexterm>
+     </term>
+     <listitem>
+      <para>
+       This variable specifies relation kind to which access is restricted.
+       It contains a comma-separated list of relation kind.  Currently, the
+       supported relation kinds are <literal>view</literal> and
+       <literal>foreign-table</literal>.
+      </para>
+     </listitem>
+     </varlistentry>
+
      </variablelist>
     </sect2>
      <sect2 id="runtime-config-client-format">

diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml
index b95ed875176f7b1811d64b9654fd3cd058948feb..f27f2987baba9e96c00883fb26d6b5774b853c16 100644 (file)
--- a/doc/src/sgml/ref/pg_dump.sgml
+++ b/doc/src/sgml/ref/pg_dump.sgml
@@ -997,6 +997,14 @@ PostgreSQL documentation
         The only exception is that an empty pattern is disallowed.
        </para>
 
+       <note>
+        <para>
+         Using wildcards in <option>--include-foreign-data</option> may result
+         in access to unexpected foreign servers. Also, to use this option securely,
+         make sure that the named server must have a trusted owner.
+        </para>
+       </note>
+
        <note>
         <para>
          When <option>--include-foreign-data</option> is specified,

diff --git a/src/backend/foreign/foreign.c b/src/backend/foreign/foreign.c
index f4f35728b40673db45db49a9e72f56dd7f30fd59..bb67d9f92b8a789f4a324c7d8f41fb5a92181a97 100644 (file)
--- a/src/backend/foreign/foreign.c
+++ b/src/backend/foreign/foreign.c
@@ -22,6 +22,7 @@
 #include "foreign/foreign.h"
 #include "funcapi.h"
 #include "miscadmin.h"
+#include "tcop/tcopprot.h"
 #include "utils/builtins.h"
 #include "utils/memutils.h"
 #include "utils/rel.h"
@@ -326,6 +327,15 @@ GetFdwRoutine(Oid fdwhandler)
    Datum       datum;
    FdwRoutine *routine;
 
+   /* Check if the access to foreign tables is restricted */
+   if (unlikely((restrict_nonsystem_relation_kind & RESTRICT_RELKIND_FOREIGN_TABLE) != 0))
+   {
+       /* there must not be built-in FDW handler  */
+       ereport(ERROR,
+               (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+                errmsg("access to non-system foreign table is restricted")));
+   }
+
    datum = OidFunctionCall0(fdwhandler);
    routine = (FdwRoutine *) DatumGetPointer(datum);
 

diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index 6b64c4a362dcd3348879364b67dae5332fb2ca8e..a5c32b91ccad049120edcb6158c574fc11adc2b0 100644 (file)
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -41,6 +41,7 @@
 #include "parser/parse_clause.h"
 #include "parser/parsetree.h"
 #include "partitioning/partprune.h"
+#include "tcop/tcopprot.h"
 #include "utils/lsyscache.h"
 
 
@@ -7141,7 +7142,19 @@ make_modifytable(PlannerInfo *root, Plan *subplan,
 
            if (rte->rtekind == RTE_RELATION &&
                rte->relkind == RELKIND_FOREIGN_TABLE)
+           {
+               /* Check if the access to foreign tables is restricted */
+               if (unlikely((restrict_nonsystem_relation_kind & RESTRICT_RELKIND_FOREIGN_TABLE) != 0))
+               {
+                   /* there must not be built-in foreign tables */
+                   Assert(rte->relid >= FirstNormalObjectId);
+                   ereport(ERROR,
+                           (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+                            errmsg("access to non-system foreign table is restricted")));
+               }
+
                fdwroutine = GetFdwRoutineByRelId(rte->relid);
+           }
            else
                fdwroutine = NULL;
        }

diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 775955363ef5f74e8a533d8440e7ef7cd8aa4c37..86655f05dc8d64794a23be6ad0360749aff5df2f 100644 (file)
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -45,6 +45,7 @@
 #include "rewrite/rewriteManip.h"
 #include "statistics/statistics.h"
 #include "storage/bufmgr.h"
+#include "tcop/tcopprot.h"
 #include "utils/builtins.h"
 #include "utils/lsyscache.h"
 #include "utils/partcache.h"
@@ -528,6 +529,17 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
    /* Grab foreign-table info using the relcache, while we have it */
    if (relation->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
    {
+       /* Check if the access to foreign tables is restricted */
+       if (unlikely((restrict_nonsystem_relation_kind & RESTRICT_RELKIND_FOREIGN_TABLE) != 0))
+       {
+           /* there must not be built-in foreign tables */
+           Assert(RelationGetRelid(relation) >= FirstNormalObjectId);
+
+           ereport(ERROR,
+                   (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+                    errmsg("access to non-system foreign table is restricted")));
+       }
+
        rel->serverid = GetForeignServerIdByRelId(RelationGetRelid(relation));
        rel->fdwroutine = GetFdwRoutineForRelation(relation, true);
    }

diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index e1d805d113edac14656375d3241d6110bc7895ad..c223a2c50aff59f1bb1e07e1401a2e27fd349882 100644 (file)
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -40,6 +40,7 @@
 #include "rewrite/rewriteManip.h"
 #include "rewrite/rewriteSearchCycle.h"
 #include "rewrite/rowsecurity.h"
+#include "tcop/tcopprot.h"
 #include "utils/builtins.h"
 #include "utils/lsyscache.h"
 #include "utils/rel.h"
@@ -1729,6 +1730,14 @@ ApplyRetrieveRule(Query *parsetree,
    if (rule->qual != NULL)
        elog(ERROR, "cannot handle qualified ON SELECT rule");
 
+   /* Check if the expansion of non-system views are restricted */
+   if (unlikely((restrict_nonsystem_relation_kind & RESTRICT_RELKIND_VIEW) != 0 &&
+                RelationGetRelid(relation) >= FirstNormalObjectId))
+       ereport(ERROR,
+               (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+                errmsg("access to non-system view \"%s\" is restricted",
+                       RelationGetRelationName(relation))));
+
    if (rt_index == parsetree->resultRelation)
    {
        /*
@@ -3212,6 +3221,14 @@ rewriteTargetView(Query *parsetree, Relation view)
        }
    }
 
+   /* Check if the expansion of non-system views are restricted */
+   if (unlikely((restrict_nonsystem_relation_kind & RESTRICT_RELKIND_VIEW) != 0 &&
+                RelationGetRelid(view) >= FirstNormalObjectId))
+       ereport(ERROR,
+               (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+                errmsg("access to non-system view \"%s\" is restricted",
+                       RelationGetRelationName(view))));
+
    /*
     * The view must be updatable, else fail.
     *

diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 034e0100bf0d3ae0d237fa320ae4b7aadfeb4c0d..7fe14c5402c51f9489dcfb20dbb33fedfb27bffb 100644 (file)
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -79,6 +79,7 @@
 #include "utils/snapmgr.h"
 #include "utils/timeout.h"
 #include "utils/timestamp.h"
+#include "utils/varlena.h"
 
 /* ----------------
  *     global variables
@@ -103,6 +104,9 @@ int         PostAuthDelay = 0;
 /* Time between checks that the client is still connected. */
 int            client_connection_check_interval = 0;
 
+/* flags for non-system relation kinds to restrict use */
+int            restrict_nonsystem_relation_kind;
+
 /* ----------------
  *     private typedefs etc
  * ----------------
@@ -3667,6 +3671,66 @@ assign_transaction_timeout(int newval, void *extra)
    }
 }
 
+/*
+ * GUC check_hook for restrict_nonsystem_relation_kind
+ */
+bool
+check_restrict_nonsystem_relation_kind(char **newval, void **extra, GucSource source)
+{
+   char       *rawstring;
+   List       *elemlist;
+   ListCell   *l;
+   int         flags = 0;
+
+   /* Need a modifiable copy of string */
+   rawstring = pstrdup(*newval);
+
+   if (!SplitIdentifierString(rawstring, ',', &elemlist))
+   {
+       /* syntax error in list */
+       GUC_check_errdetail("List syntax is invalid.");
+       pfree(rawstring);
+       list_free(elemlist);
+       return false;
+   }
+
+   foreach(l, elemlist)
+   {
+       char       *tok = (char *) lfirst(l);
+
+       if (pg_strcasecmp(tok, "view") == 0)
+           flags |= RESTRICT_RELKIND_VIEW;
+       else if (pg_strcasecmp(tok, "foreign-table") == 0)
+           flags |= RESTRICT_RELKIND_FOREIGN_TABLE;
+       else
+       {
+           GUC_check_errdetail("Unrecognized key word: \"%s\".", tok);
+           pfree(rawstring);
+           list_free(elemlist);
+           return false;
+       }
+   }
+
+   pfree(rawstring);
+   list_free(elemlist);
+
+   /* Save the flags in *extra, for use by the assign function */
+   *extra = guc_malloc(ERROR, sizeof(int));
+   *((int *) *extra) = flags;
+
+   return true;
+}
+
+/*
+ * GUC assign_hook for restrict_nonsystem_relation_kind
+ */
+void
+assign_restrict_nonsystem_relation_kind(const char *newval, void *extra)
+{
+   int        *flags = (int *) extra;
+
+   restrict_nonsystem_relation_kind = *flags;
+}
 
 /*
  * set_debug_options --- apply "-d N" command line option

diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c
index 6f4188599b18401e6ce59fb963b6b0ede42778c7..319f6d7cc028f00ef8f8742352b42eeee80ae6eb 100644 (file)
--- a/src/backend/utils/misc/guc_tables.c
+++ b/src/backend/utils/misc/guc_tables.c
@@ -578,6 +578,7 @@ static char *server_encoding_string;
 static char *server_version_string;
 static int server_version_num;
 static char *debug_io_direct_string;
+static char *restrict_nonsystem_relation_kind_string;
 
 #ifdef HAVE_SYSLOG
 #define    DEFAULT_SYSLOG_FACILITY LOG_LOCAL0
@@ -4705,6 +4706,17 @@ struct config_string ConfigureNamesString[] =
        check_synchronized_standby_slots, assign_synchronized_standby_slots, NULL
    },
 
+   {
+       {"restrict_nonsystem_relation_kind", PGC_USERSET, CLIENT_CONN_STATEMENT,
+           gettext_noop("Sets relation kinds of non-system relation to restrict use"),
+           NULL,
+           GUC_LIST_INPUT | GUC_NOT_IN_SAMPLE
+       },
+       &restrict_nonsystem_relation_kind_string,
+       "",
+       check_restrict_nonsystem_relation_kind, assign_restrict_nonsystem_relation_kind, NULL
+   },
+
    /* End-of-list marker */
    {
        {NULL, 0, 0, NULL, NULL}, NULL, NULL, NULL, NULL, NULL

diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 9202a43eb20fbc9be438762f7ce4d5917a25a74e..9737e1e189f4847b463c6618bdf8c82cc1066c36 100644 (file)
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -336,6 +336,7 @@ static bool nonemptyReloptions(const char *reloptions);
 static void appendReloptionsArrayAH(PQExpBuffer buffer, const char *reloptions,
                                    const char *prefix, Archive *fout);
 static char *get_synchronized_snapshot(Archive *fout);
+static void set_restrict_relation_kind(Archive *AH, const char *value);
 static void setupDumpWorker(Archive *AH);
 static TableInfo *getRootTableInfo(const TableInfo *tbinfo);
 static bool forcePartitionRootLoad(const TableInfo *tbinfo);
@@ -1293,6 +1294,13 @@ setup_connection(Archive *AH, const char *dumpencoding,
            ExecuteSqlStatement(AH, "SET row_security = off");
    }
 
+   /*
+    * For security reasons, we restrict the expansion of non-system views and
+    * access to foreign tables during the pg_dump process. This restriction
+    * is adjusted when dumping foreign table data.
+    */
+   set_restrict_relation_kind(AH, "view, foreign-table");
+
    /*
     * Initialize prepared-query state to "nothing prepared".  We do this here
     * so that a parallel dump worker will have its own state.
@@ -2161,6 +2169,10 @@ dumpTableData_copy(Archive *fout, const void *dcontext)
     */
    if (tdinfo->filtercond || tbinfo->relkind == RELKIND_FOREIGN_TABLE)
    {
+       /* Temporary allows to access to foreign tables to dump data */
+       if (tbinfo->relkind == RELKIND_FOREIGN_TABLE)
+           set_restrict_relation_kind(fout, "view");
+
        appendPQExpBufferStr(q, "COPY (SELECT ");
        /* klugery to get rid of parens in column list */
        if (strlen(column_list) > 2)
@@ -2272,6 +2284,11 @@ dumpTableData_copy(Archive *fout, const void *dcontext)
                       classname);
 
    destroyPQExpBuffer(q);
+
+   /* Revert back the setting */
+   if (tbinfo->relkind == RELKIND_FOREIGN_TABLE)
+       set_restrict_relation_kind(fout, "view, foreign-table");
+
    return 1;
 }
 
@@ -2298,6 +2315,10 @@ dumpTableData_insert(Archive *fout, const void *dcontext)
    int         rows_per_statement = dopt->dump_inserts;
    int         rows_this_statement = 0;
 
+   /* Temporary allows to access to foreign tables to dump data */
+   if (tbinfo->relkind == RELKIND_FOREIGN_TABLE)
+       set_restrict_relation_kind(fout, "view");
+
    /*
     * If we're going to emit INSERTs with column names, the most efficient
     * way to deal with generated columns is to exclude them entirely.  For
@@ -2537,6 +2558,10 @@ dumpTableData_insert(Archive *fout, const void *dcontext)
        destroyPQExpBuffer(insertStmt);
    free(attgenerated);
 
+   /* Revert back the setting */
+   if (tbinfo->relkind == RELKIND_FOREIGN_TABLE)
+       set_restrict_relation_kind(fout, "view, foreign-table");
+
    return 1;
 }
 
@@ -4710,6 +4735,28 @@ is_superuser(Archive *fout)
    return false;
 }
 
+/*
+ * Set the given value to restrict_nonsystem_relation_kind value. Since
+ * restrict_nonsystem_relation_kind is introduced in minor version releases,
+ * the setting query is effective only where available.
+ */
+static void
+set_restrict_relation_kind(Archive *AH, const char *value)
+{
+   PQExpBuffer query = createPQExpBuffer();
+   PGresult   *res;
+
+   appendPQExpBuffer(query,
+                     "SELECT set_config(name, '%s', false) "
+                     "FROM pg_settings "
+                     "WHERE name = 'restrict_nonsystem_relation_kind'",
+                     value);
+   res = ExecuteSqlQuery(AH, query->data, PGRES_TUPLES_OK);
+
+   PQclear(res);
+   destroyPQExpBuffer(query);
+}
+
 /*
  * getSubscriptions
  *   get information about subscriptions

diff --git a/src/include/tcop/tcopprot.h b/src/include/tcop/tcopprot.h
index 643ce9cffab611c83c07790ca4b7d286a0c5c811..180d5a2d2275f370dd10fc4c2e223f8802eda3fb 100644 (file)
--- a/src/include/tcop/tcopprot.h
+++ b/src/include/tcop/tcopprot.h
@@ -42,6 +42,12 @@ typedef enum
 
 extern PGDLLIMPORT int log_statement;
 
+/* Flags for restrict_nonsystem_relation_kind value */
+#define RESTRICT_RELKIND_VIEW          0x01
+#define RESTRICT_RELKIND_FOREIGN_TABLE 0x02
+
+extern PGDLLIMPORT int restrict_nonsystem_relation_kind;
+
 extern List *pg_parse_query(const char *query_string);
 extern List *pg_rewrite_query(Query *query);
 extern List *pg_analyze_and_rewrite_fixedparams(RawStmt *parsetree,

diff --git a/src/include/utils/guc_hooks.h b/src/include/utils/guc_hooks.h
index 070d3f2a1ad053dca6be5d275e0a491fd17dce37..8fd91af3887f762305681b04cabcf5dbf07825e8 100644 (file)
--- a/src/include/utils/guc_hooks.h
+++ b/src/include/utils/guc_hooks.h
@@ -127,6 +127,9 @@ extern void assign_recovery_target_xid(const char *newval, void *extra);
 extern bool check_role(char **newval, void **extra, GucSource source);
 extern void assign_role(const char *newval, void *extra);
 extern const char *show_role(void);
+extern bool check_restrict_nonsystem_relation_kind(char **newval, void **extra,
+                                                  GucSource source);
+extern void assign_restrict_nonsystem_relation_kind(const char *newval, void *extra);
 extern bool check_search_path(char **newval, void **extra, GucSource source);
 extern void assign_search_path(const char *newval, void *extra);
 extern bool check_serial_buffers(int *newval, void **extra, GucSource source);

diff --git a/src/test/regress/expected/create_view.out b/src/test/regress/expected/create_view.out
index 61825ef7d4ee198fe378abfd7216b42f8a0adaf0..f3f8c7b5a2fa0f52ccefd4d0d276461e6769b356 100644 (file)
--- a/src/test/regress/expected/create_view.out
+++ b/src/test/regress/expected/create_view.out
@@ -2202,6 +2202,21 @@ select pg_get_viewdef('tt26v', true);
     FROM ( VALUES (1,2,3)) v(x, y, z);
 (1 row)
 
+-- test restriction on non-system view expansion.
+create table tt27v_tbl (a int);
+create view tt27v as select a from tt27v_tbl;
+set restrict_nonsystem_relation_kind to 'view';
+select a from tt27v where a > 0; -- Error
+ERROR:  access to non-system view "tt27v" is restricted
+insert into tt27v values (1); -- Error
+ERROR:  access to non-system view "tt27v" is restricted
+select viewname from pg_views where viewname = 'tt27v'; -- Ok to access a system view.
+ viewname 
+----------
+ tt27v
+(1 row)
+
+reset restrict_nonsystem_relation_kind;
 -- clean up all the random objects we made above
 DROP SCHEMA temp_view_test CASCADE;
 NOTICE:  drop cascades to 27 other objects
@@ -2233,7 +2248,7 @@ drop cascades to view aliased_view_2
 drop cascades to view aliased_view_3
 drop cascades to view aliased_view_4
 DROP SCHEMA testviewschm2 CASCADE;
-NOTICE:  drop cascades to 77 other objects
+NOTICE:  drop cascades to 79 other objects
 DETAIL:  drop cascades to table t1
 drop cascades to view temporal1
 drop cascades to view temporal2
@@ -2311,3 +2326,5 @@ drop cascades to view tt23v
 drop cascades to view tt24v
 drop cascades to view tt25v
 drop cascades to view tt26v
+drop cascades to table tt27v_tbl
+drop cascades to view tt27v

diff --git a/src/test/regress/sql/create_view.sql b/src/test/regress/sql/create_view.sql
index 8838a40f7abbe6c9ed0d8be02ad48cd2cc800882..3a78be1b0c7c486b60fe82432a87cd539adafbd2 100644 (file)
--- a/src/test/regress/sql/create_view.sql
+++ b/src/test/regress/sql/create_view.sql
@@ -813,6 +813,15 @@ select x + y + z as c1,
 from (values(1,2,3)) v(x,y,z);
 select pg_get_viewdef('tt26v', true);
 
+-- test restriction on non-system view expansion.
+create table tt27v_tbl (a int);
+create view tt27v as select a from tt27v_tbl;
+set restrict_nonsystem_relation_kind to 'view';
+select a from tt27v where a > 0; -- Error
+insert into tt27v values (1); -- Error
+select viewname from pg_views where viewname = 'tt27v'; -- Ok to access a system view.
+reset restrict_nonsystem_relation_kind;
+
 -- clean up all the random objects we made above
 DROP SCHEMA temp_view_test CASCADE;
 DROP SCHEMA testviewschm2 CASCADE;