Add a security_barrier option for views.

When a view is marked as a security barrier, it will not be pulled up into the containing query, and no quals will be pushed down into it, so that no function or operator chosen by the user can be applied to rows not exposed by the view. Views not configured with this option cannot provide robust row-level security, but will perform far better. Patch by KaiGai Kohei; original problem report by Heikki Linnakangas (in October 2009!). Review (in earlier versions) by Noah Misch and others. Design advice by Tom Lane and myself. Further review and cleanup by me.
2011-12-22 16:15:57 -05:00 · 2011-12-22 16:15:57 -05:00 · 0e4611c023
commit 0e4611c023
parent f90dd28062
22 changed files with 300 additions and 35 deletions
--- a/doc/src/sgml/ref/alter_view.sgml
+++ b/doc/src/sgml/ref/alter_view.sgml
@ -26,6 +26,8 @@ ALTER VIEW <replaceable class="parameter">name</replaceable> ALTER [ COLUMN ] <r
 ALTER VIEW <replaceable class="parameter">name</replaceable> OWNER TO <replaceable class="PARAMETER">new_owner</replaceable>
 ALTER VIEW <replaceable class="parameter">name</replaceable> RENAME TO <replaceable class="parameter">new_name</replaceable>
 ALTER VIEW <replaceable class="parameter">name</replaceable> SET SCHEMA <replaceable class="parameter">new_schema</replaceable>
+ALTER VIEW <replaceable class="parameter">name</replaceable> SET ( <replaceable class="parameter">view_option_name</replaceable> [= <replaceable class="parameter">view_option_value</replaceable>] [, ... ] )
+ALTER VIEW <replaceable class="parameter">name</replaceable> RESET ( <replaceable class="parameter">view_option_name</replaceable> [, ... ] )
 </synopsis>
 </refsynopsisdiv>

@ -102,6 +104,24 @@ ALTER VIEW <replaceable class="parameter">name</replaceable> SET SCHEMA <replace
     </para>
    </listitem>
   </varlistentry>
+
+   <varlistentry>
+    <term><replaceable class="parameter">view_option_name</replaceable></term>
+    <listitem>
+     <para>
+      The name of a view option to be set or reset.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
+    <term><replaceable class="parameter">view_option_name</replaceable></term>
+    <listitem>
+     <para>
+      The new value for a view option.
+     </para>
+    </listitem>
+   </varlistentry>
  </variablelist>
 </refsect1>

--- a/doc/src/sgml/ref/create_view.sgml
+++ b/doc/src/sgml/ref/create_view.sgml
@ -22,6 +22,7 @@ PostgreSQL documentation
 <refsynopsisdiv>
 <synopsis>
 CREATE [ OR REPLACE ] [ TEMP | TEMPORARY ] VIEW <replaceable class="PARAMETER">name</replaceable> [ ( <replaceable class="PARAMETER">column_name</replaceable> [, ...] ) ]
+    [ WITH ( <replaceable class="PARAMETER">view_option_name</replaceable> [= <replaceable class="PARAMETER">view_option_value</replaceable>] [, ... ] ) ]
    AS <replaceable class="PARAMETER">query</replaceable>
 </synopsis>
 </refsynopsisdiv>
@ -98,6 +99,18 @@ CREATE [ OR REPLACE ] [ TEMP | TEMPORARY ] VIEW <replaceable class="PARAMETER">n
    </listitem>
   </varlistentry>

+   <varlistentry>
+    <term><literal>WITH ( <replaceable class="PARAMETER">view_option_name</replaceable> [= <replaceable class="PARAMETER">view_option_value</replaceable>] [, ... ] )</literal></term>
+    <listitem>
+     <para>
+      This clause specifies optional parameters for a view; currently, the
+      only suppored parameter name is <literal>security_barrier</literal>,
+      which should be enabled when a view is intended to provide row-level
+      security.  See <xref linkend="rules-privileges"> for full details.
+     </para>
+    </listitem>
+   </varlistentry>
+
   <varlistentry>
    <term><replaceable class="parameter">query</replaceable></term>
    <listitem>
--- a/doc/src/sgml/rules.sgml
+++ b/doc/src/sgml/rules.sgml
@ -1822,8 +1822,9 @@ GRANT SELECT ON phone_number TO secretary;
 <para>
    Note that while views can be used to hide the contents of certain
    columns using the technique shown above, they cannot be used to reliably
-    conceal the data in unseen rows.  For example, the following view is
-    insecure:
+    conceal the data in unseen rows unless the
+    <literal>security_barrier</literal> flag has been set.  For example,
+    the following view is insecure:
 <programlisting>
 CREATE VIEW phone_number AS
    SELECT person, phone FROM phone_data WHERE phone NOT LIKE '412%';
@ -1870,6 +1871,40 @@ SELECT * FROM phone_number WHERE tricky(person, phone);
    which references <literal>shoelace_log</> is an unqualified
    <literal>INSERT</>.  This might not be true in more complex scenarios.
 </para>
+
+<para>
+    When it is necessary for a view to provide row-level security, the
+    <literal>security_barrier</literal> attribute should be applied to
+    the view.  This prevents maliciously-chosen functions and operators from
+    being invoked on rows until afterthe view has done its work.  For
+    example, if the view shown above had been created like this, it would
+    be secure:
+<programlisting>
+CREATE VIEW phone_number WITH (security_barrier) AS
+    SELECT person, phone FROM phone_data WHERE phone NOT LIKE '412%';
+</programlisting>
+    Views created with the <literal>security_barrier</literal> may perform
+    far worse than views created without this option.  In general, there is
+    no way to avoid this: the fastest possible plan must be rejected
+    if it may compromise security.  For this reason, this option is not
+    enabled by default.
+</para>
+
+<para>
+    It is important to understand that even a view created with the
+    <literal>security_barrier</literal> option is intended to be secure only
+    in the limited sense that the contents of the invisible tuples will not
+    passed to possibly-insecure functions.  The user may well have other means
+    of making inferences about the unseen data; for example, they can see the
+    query plan using <command>EXPLAIN</command>, or measure the runtime of
+    queries against the view.  A malicious attacker might be able to infer
+    something about the amount of unseen data, or even gain some information
+    about the data distribution or most common values (since these things may
+    affect the runtime of the plan; or even, since they are also reflected in
+    the optimizer statistics, the choice of plan).  If these types of "covert
+    channel" attacks are of concern, it is probably unwise to grant any access
+    to the data at all.
+</para>
 </sect1>

 <sect1 id="rules-status">
--- a/src/backend/access/common/reloptions.c
+++ b/src/backend/access/common/reloptions.c
@ -67,6 +67,14 @@ static relopt_bool boolRelOpts[] =
 		},
 		true
 	},
+	{
+		{
+			"security_barrier",
+			"View acts as a row security barrier",
+			RELOPT_KIND_VIEW
+		},
+		false
+	},
 	/* list terminator */
 	{{NULL}}
 };
@ -781,6 +789,7 @@ extractRelOptions(HeapTuple tuple, TupleDesc tupdesc, Oid amoptions)
 	{
 		case RELKIND_RELATION:
 		case RELKIND_TOASTVALUE:
+		case RELKIND_VIEW:
 		case RELKIND_UNCATALOGED:
 			options = heap_reloptions(classForm->relkind, datum, false);
 			break;
@ -1139,7 +1148,9 @@ default_reloptions(Datum reloptions, bool validate, relopt_kind kind)
 		{"autovacuum_vacuum_scale_factor", RELOPT_TYPE_REAL,
 		offsetof(StdRdOptions, autovacuum) +offsetof(AutoVacOpts, vacuum_scale_factor)},
 		{"autovacuum_analyze_scale_factor", RELOPT_TYPE_REAL,
-		offsetof(StdRdOptions, autovacuum) +offsetof(AutoVacOpts, analyze_scale_factor)}
+		offsetof(StdRdOptions, autovacuum) +offsetof(AutoVacOpts, analyze_scale_factor)},
+		{"security_barrier", RELOPT_TYPE_BOOL,
+		offsetof(StdRdOptions, security_barrier)},
 	};

 	options = parseRelOptions(reloptions, validate, kind, &numoptions);
@ -1159,7 +1170,7 @@ default_reloptions(Datum reloptions, bool validate, relopt_kind kind)
 }

 /*
- * Parse options for heaps and toast tables.
+ * Parse options for heaps, views and toast tables.
 */
 bytea *
 heap_reloptions(char relkind, Datum reloptions, bool validate)
@ -1181,6 +1192,8 @@ heap_reloptions(char relkind, Datum reloptions, bool validate)
 			return (bytea *) rdopts;
 		case RELKIND_RELATION:
 			return default_reloptions(reloptions, validate, RELOPT_KIND_HEAP);
+		case RELKIND_VIEW:
+			return default_reloptions(reloptions, validate, RELOPT_KIND_VIEW);
 		default:
 			/* other relkinds are not supported */
 			return NULL;
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@ -366,7 +366,9 @@ static void ATExecDropCluster(Relation rel, LOCKMODE lockmode);
 static void ATPrepSetTableSpace(AlteredTableInfo *tab, Relation rel,
 					char *tablespacename, LOCKMODE lockmode);
 static void ATExecSetTableSpace(Oid tableOid, Oid newTableSpace, LOCKMODE lockmode);
-static void ATExecSetRelOptions(Relation rel, List *defList, bool isReset, LOCKMODE lockmode);
+static void ATExecSetRelOptions(Relation rel, List *defList,
+								AlterTableType operation,
+								LOCKMODE lockmode);
 static void ATExecEnableDisableTrigger(Relation rel, char *trigname,
 					   char fires_when, bool skip_system, LOCKMODE lockmode);
 static void ATExecEnableDisableRule(Relation rel, char *rulename,
@ -2866,6 +2868,7 @@ AlterTableGetLockLevel(List *cmds)
 			case AT_DropCluster:
 			case AT_SetRelOptions:
 			case AT_ResetRelOptions:
+			case AT_ReplaceRelOptions:
 			case AT_SetOptions:
 			case AT_ResetOptions:
 			case AT_SetStorage:
@ -3094,8 +3097,9 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 			pass = AT_PASS_MISC;	/* doesn't actually matter */
 			break;
 		case AT_SetRelOptions:	/* SET (...) */
-		case AT_ResetRelOptions:		/* RESET (...) */
-			ATSimplePermissions(rel, ATT_TABLE | ATT_INDEX);
+		case AT_ResetRelOptions:	/* RESET (...) */
+		case AT_ReplaceRelOptions:	/* reset them all, then set just these */
+			ATSimplePermissions(rel, ATT_TABLE | ATT_INDEX | ATT_VIEW);
 			/* This command never recurses */
 			/* No command-specific prep needed */
 			pass = AT_PASS_MISC;
@ -3338,12 +3342,10 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			 */
 			break;
 		case AT_SetRelOptions:	/* SET (...) */
-			ATExecSetRelOptions(rel, (List *) cmd->def, false, lockmode);
-			break;
 		case AT_ResetRelOptions:		/* RESET (...) */
-			ATExecSetRelOptions(rel, (List *) cmd->def, true, lockmode);
+		case AT_ReplaceRelOptions:		/* replace entire option list */
+			ATExecSetRelOptions(rel, (List *) cmd->def, cmd->subtype, lockmode);
 			break;
-
 		case AT_EnableTrig:		/* ENABLE TRIGGER name */
 			ATExecEnableDisableTrigger(rel, cmd->name,
 								   TRIGGER_FIRES_ON_ORIGIN, false, lockmode);
@ -8271,10 +8273,11 @@ ATPrepSetTableSpace(AlteredTableInfo *tab, Relation rel, char *tablespacename, L
 }

 /*
- * ALTER TABLE/INDEX SET (...) or RESET (...)
+ * Set, reset, or replace reloptions.
 */
 static void
-ATExecSetRelOptions(Relation rel, List *defList, bool isReset, LOCKMODE lockmode)
+ATExecSetRelOptions(Relation rel, List *defList, AlterTableType operation,
+					LOCKMODE lockmode)
 {
 	Oid			relid;
 	Relation	pgclass;
@ -8288,28 +8291,44 @@ ATExecSetRelOptions(Relation rel, List *defList, bool isReset, LOCKMODE lockmode
 	bool		repl_repl[Natts_pg_class];
 	static char *validnsps[] = HEAP_RELOPT_NAMESPACES;

-	if (defList == NIL)
+	if (defList == NIL && operation != AT_ReplaceRelOptions)
 		return;					/* nothing to do */

 	pgclass = heap_open(RelationRelationId, RowExclusiveLock);

-	/* Get the old reloptions */
+	/* Fetch heap tuple */
 	relid = RelationGetRelid(rel);
 	tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
 	if (!HeapTupleIsValid(tuple))
 		elog(ERROR, "cache lookup failed for relation %u", relid);

-	datum = SysCacheGetAttr(RELOID, tuple, Anum_pg_class_reloptions, &isnull);
+	if (operation == AT_ReplaceRelOptions)
+	{
+		/*
+		 * If we're supposed to replace the reloptions list, we just pretend
+		 * there were none before.
+		 */
+		datum = (Datum) 0;
+		isnull = true;
+	}
+	else
+	{
+		/* Get the old reloptions */
+		datum = SysCacheGetAttr(RELOID, tuple, Anum_pg_class_reloptions,
+								&isnull);
+	}

 	/* Generate new proposed reloptions (text array) */
 	newOptions = transformRelOptions(isnull ? (Datum) 0 : datum,
-								   defList, NULL, validnsps, false, isReset);
+								   defList, NULL, validnsps, false,
+								   operation == AT_ResetRelOptions);

 	/* Validate */
 	switch (rel->rd_rel->relkind)
 	{
 		case RELKIND_RELATION:
 		case RELKIND_TOASTVALUE:
+		case RELKIND_VIEW:
 			(void) heap_reloptions(rel->rd_rel->relkind, newOptions, true);
 			break;
 		case RELKIND_INDEX:
@ -8357,15 +8376,30 @@ ATExecSetRelOptions(Relation rel, List *defList, bool isReset, LOCKMODE lockmode

 		toastrel = heap_open(toastid, lockmode);

-		/* Get the old reloptions */
+		/* Fetch heap tuple */
 		tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(toastid));
 		if (!HeapTupleIsValid(tuple))
 			elog(ERROR, "cache lookup failed for relation %u", toastid);

-		datum = SysCacheGetAttr(RELOID, tuple, Anum_pg_class_reloptions, &isnull);
+		if (operation == AT_ReplaceRelOptions)
+		{
+			/*
+			 * If we're supposed to replace the reloptions list, we just
+			 * pretend there were none before.
+			 */
+			datum = (Datum) 0;
+			isnull = true;
+		}
+		else
+		{
+			/* Get the old reloptions */
+			datum = SysCacheGetAttr(RELOID, tuple, Anum_pg_class_reloptions,
+									&isnull);
+		}

 		newOptions = transformRelOptions(isnull ? (Datum) 0 : datum,
-								defList, "toast", validnsps, false, isReset);
+								defList, "toast", validnsps, false,
+								operation == AT_ResetRelOptions);

 		(void) heap_reloptions(RELKIND_TOASTVALUE, newOptions, true);

--- a/src/backend/commands/view.c
+++ b/src/backend/commands/view.c
@ -32,6 +32,7 @@
 #include "utils/builtins.h"
 #include "utils/lsyscache.h"
 #include "utils/rel.h"
+#include "utils/syscache.h"


 static void checkViewTupleDesc(TupleDesc newdesc, TupleDesc olddesc);
@ -98,7 +99,7 @@ isViewOnTempTable_walker(Node *node, void *context)
 */
 static Oid
 DefineVirtualRelation(const RangeVar *relation, List *tlist, bool replace,
-					  Oid namespaceId)
+					  Oid namespaceId, List *options)
 {
 	Oid			viewOid;
 	CreateStmt *createStmt = makeNode(CreateStmt);
@ -166,6 +167,8 @@ DefineVirtualRelation(const RangeVar *relation, List *tlist, bool replace,
 	{
 		Relation	rel;
 		TupleDesc	descriptor;
+		List	   *atcmds = NIL;
+		AlterTableCmd *atcmd;

 		/*
 		 * Yes.  Get exclusive lock on the existing view ...
@ -203,6 +206,15 @@ DefineVirtualRelation(const RangeVar *relation, List *tlist, bool replace,
 		descriptor = BuildDescForRelation(attrList);
 		checkViewTupleDesc(descriptor, rel->rd_att);

+		/*
+		 * The new options list replaces the existing options list, even
+		 * if it's empty.
+		 */
+		atcmd = makeNode(AlterTableCmd);
+		atcmd->subtype = AT_ReplaceRelOptions;
+		atcmd->def = (Node *) options;
+		atcmds = lappend(atcmds, atcmd);
+
 		/*
 		 * If new attributes have been added, we must add pg_attribute entries
 		 * for them.  It is convenient (although overkill) to use the ALTER
@ -210,14 +222,11 @@ DefineVirtualRelation(const RangeVar *relation, List *tlist, bool replace,
 		 */
 		if (list_length(attrList) > rel->rd_att->natts)
 		{
-			List	   *atcmds = NIL;
 			ListCell   *c;
 			int			skip = rel->rd_att->natts;

 			foreach(c, attrList)
 			{
-				AlterTableCmd *atcmd;
-
 				if (skip > 0)
 				{
 					skip--;
@ -228,9 +237,11 @@ DefineVirtualRelation(const RangeVar *relation, List *tlist, bool replace,
 				atcmd->def = (Node *) lfirst(c);
 				atcmds = lappend(atcmds, atcmd);
 			}
-			AlterTableInternal(viewOid, atcmds, true);
 		}

+		/* OK, let's do it. */
+		AlterTableInternal(viewOid, atcmds, true);
+
 		/*
 		 * Seems okay, so return the OID of the pre-existing view.
 		 */
@ -250,7 +261,8 @@ DefineVirtualRelation(const RangeVar *relation, List *tlist, bool replace,
 		createStmt->tableElts = attrList;
 		createStmt->inhRelations = NIL;
 		createStmt->constraints = NIL;
-		createStmt->options = list_make1(defWithOids(false));
+		createStmt->options = options;
+		createStmt->options = lappend(options, defWithOids(false));
 		createStmt->oncommit = ONCOMMIT_NOOP;
 		createStmt->tablespacename = NULL;
 		createStmt->if_not_exists = false;
@ -513,7 +525,7 @@ DefineView(ViewStmt *stmt, const char *queryString)
 	 * aborted.
 	 */
 	viewOid = DefineVirtualRelation(view, viewParse->targetList,
-									stmt->replace, namespaceId);
+									stmt->replace, namespaceId, stmt->options);

 	/*
 	 * The relation we have just created is not visible to any other commands
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@ -1965,6 +1965,7 @@ _copyRangeTblEntry(const RangeTblEntry *from)
 	COPY_SCALAR_FIELD(relid);
 	COPY_SCALAR_FIELD(relkind);
 	COPY_NODE_FIELD(subquery);
+	COPY_SCALAR_FIELD(security_barrier);
 	COPY_SCALAR_FIELD(jointype);
 	COPY_NODE_FIELD(joinaliasvars);
 	COPY_NODE_FIELD(funcexpr);
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@ -2228,6 +2228,7 @@ _equalRangeTblEntry(const RangeTblEntry *a, const RangeTblEntry *b)
 	COMPARE_SCALAR_FIELD(relid);
 	COMPARE_SCALAR_FIELD(relkind);
 	COMPARE_NODE_FIELD(subquery);
+	COMPARE_SCALAR_FIELD(security_barrier);
 	COMPARE_SCALAR_FIELD(jointype);
 	COMPARE_NODE_FIELD(joinaliasvars);
 	COMPARE_NODE_FIELD(funcexpr);
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@ -2321,6 +2321,7 @@ _outRangeTblEntry(StringInfo str, const RangeTblEntry *node)
 			break;
 		case RTE_SUBQUERY:
 			WRITE_NODE_FIELD(subquery);
+			WRITE_BOOL_FIELD(security_barrier);
 			break;
 		case RTE_JOIN:
 			WRITE_ENUM_FIELD(jointype, JoinType);
--- a/src/backend/nodes/readfuncs.c
+++ b/src/backend/nodes/readfuncs.c
@ -1192,6 +1192,7 @@ _readRangeTblEntry(void)
 			break;
 		case RTE_SUBQUERY:
 			READ_NODE_FIELD(subquery);
+			READ_BOOL_FIELD(security_barrier);
 			break;
 		case RTE_JOIN:
 			READ_ENUM_FIELD(jointype, JoinType);
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@ -744,6 +744,11 @@ set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
 	 * pseudoconstant clauses; better to have the gating node above the
 	 * subquery.
 	 *
+	 * Also, if the sub-query has "security_barrier" flag, it means the
+	 * sub-query originated from a view that must enforce row-level security.
+	 * We must not push down quals in order to avoid information leaks, either
+	 * via side-effects or error output.
+	 *
 	 * Non-pushed-down clauses will get evaluated as qpquals of the
 	 * SubqueryScan node.
 	 *
@ -762,7 +767,16 @@ set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
 			RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
 			Node	   *clause = (Node *) rinfo->clause;

+			/*
+			 * XXX.  You might wonder why we're testing rte->security_barrier
+			 * qual-by-qual here rather than hoisting the test up into the
+			 * surrounding if statement; after all, the answer will be the
+			 * same for all quals.  The answer is that we expect to shortly
+			 * change this logic to allow pushing down some quals that use only
+			 * "leakproof" operators even through a security barrier.
+			 */
 			if (!rinfo->pseudoconstant &&
+				!rte->security_barrier &&
 				qual_is_pushdown_safe(subquery, rti, clause, differentTypes))
 			{
 				/* Push it down */
--- a/src/backend/optimizer/prep/prepjointree.c
+++ b/src/backend/optimizer/prep/prepjointree.c
@ -543,6 +543,7 @@ pull_up_subqueries(PlannerInfo *root, Node *jtnode,
 		 */
 		if (rte->rtekind == RTE_SUBQUERY &&
 			is_simple_subquery(rte->subquery) &&
+			!rte->security_barrier &&
 			(containing_appendrel == NULL ||
 			 is_safe_append_member(rte->subquery)))
 			return pull_up_simple_subquery(root, jtnode, rte,
@ -712,6 +713,7 @@ pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
 	 * pull_up_subqueries.
 	 */
 	if (is_simple_subquery(subquery) &&
+		!rte->security_barrier &&
 		(containing_appendrel == NULL || is_safe_append_member(subquery)))
 	{
 		/* good to go */
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@ -7322,26 +7322,28 @@ transaction_mode_list_or_empty:
 *
 *****************************************************************************/

-ViewStmt: CREATE OptTemp VIEW qualified_name opt_column_list
+ViewStmt: CREATE OptTemp VIEW qualified_name opt_column_list opt_reloptions
 				AS SelectStmt opt_check_option
 				{
 					ViewStmt *n = makeNode(ViewStmt);
 					n->view = $4;
 					n->view->relpersistence = $2;
 					n->aliases = $5;
-					n->query = $7;
+					n->query = $8;
 					n->replace = false;
+					n->options = $6;
 					$$ = (Node *) n;
 				}
-		| CREATE OR REPLACE OptTemp VIEW qualified_name opt_column_list
+		| CREATE OR REPLACE OptTemp VIEW qualified_name opt_column_list opt_reloptions
 				AS SelectStmt opt_check_option
 				{
 					ViewStmt *n = makeNode(ViewStmt);
 					n->view = $6;
 					n->view->relpersistence = $4;
 					n->aliases = $7;
-					n->query = $9;
+					n->query = $10;
 					n->replace = true;
+					n->options = $8;
 					$$ = (Node *) n;
 				}
 		;
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@ -1382,6 +1382,7 @@ ApplyRetrieveRule(Query *parsetree,

 	rte->rtekind = RTE_SUBQUERY;
 	rte->relid = InvalidOid;
+	rte->security_barrier = RelationIsSecurityView(relation);
 	rte->subquery = rule_action;
 	rte->inh = false;			/* must not be set for a subquery */

--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@ -4372,6 +4372,19 @@ examine_simple_variable(PlannerInfo *root, Var *var,
 			subquery->distinctClause)
 			return;

+		/*
+		 * If the sub-query originated from a view with the security_barrier
+		 * attribute, we treat it as a black-box from outside of the view.
+		 * This is probably a harsher restriction than necessary; it's
+		 * certainly OK for the selectivity estimator (which is a C function,
+		 * and therefore omnipotent anyway) to look at the statistics.  But
+		 * many selectivity estimators will happily *invoke the operator
+		 * function* to try to work out a good estimate - and that's not OK.
+		 * So for now, we do this.
+		 */
+		if (rte->security_barrier)
+			return;
+
 		/*
 		 * OK, fetch RelOptInfo for subquery.  Note that we don't change the
 		 * rel returned in vardata, since caller expects it to be a rel of the
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@ -374,6 +374,7 @@ RelationParseRelOptions(Relation relation, HeapTuple tuple)
 		case RELKIND_RELATION:
 		case RELKIND_TOASTVALUE:
 		case RELKIND_INDEX:
+		case RELKIND_VIEW:
 			break;
 		default:
 			return;
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@ -12397,8 +12397,10 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 		if (binary_upgrade)
 			binary_upgrade_set_pg_class_oids(q, tbinfo->dobj.catId.oid, false);

-		appendPQExpBuffer(q, "CREATE VIEW %s AS\n    %s\n",
-						  fmtId(tbinfo->dobj.name), viewdef);
+		appendPQExpBuffer(q, "CREATE VIEW %s", fmtId(tbinfo->dobj.name));
+		if (tbinfo->reloptions && strlen(tbinfo->reloptions) > 0)
+			appendPQExpBuffer(q, " WITH (%s)", tbinfo->reloptions);
+		appendPQExpBuffer(q, " AS\n    %s\n", viewdef);

 		appendPQExpBuffer(labelq, "VIEW %s",
 						  fmtId(tbinfo->dobj.name));
--- a/src/include/access/reloptions.h
+++ b/src/include/access/reloptions.h
@ -43,8 +43,9 @@ typedef enum relopt_kind
 	RELOPT_KIND_ATTRIBUTE = (1 << 6),
 	RELOPT_KIND_TABLESPACE = (1 << 7),
 	RELOPT_KIND_SPGIST = (1 << 8),
+	RELOPT_KIND_VIEW = (1 << 9),
 	/* if you add a new kind, make sure you update "last_default" too */
-	RELOPT_KIND_LAST_DEFAULT = RELOPT_KIND_SPGIST,
+	RELOPT_KIND_LAST_DEFAULT = RELOPT_KIND_VIEW,
 	/* some compilers treat enums as signed ints, so we can't use 1 << 31 */
 	RELOPT_KIND_MAX = (1 << 30)
 } relopt_kind;
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@ -706,6 +706,7 @@ typedef struct RangeTblEntry
 	 * Fields valid for a subquery RTE (else NULL):
 	 */
 	Query	   *subquery;		/* the sub-query */
+	bool		security_barrier;	/* subquery from security_barrier view */

 	/*
 	 * Fields valid for a join RTE (else NULL/zero):
@ -1208,6 +1209,7 @@ typedef enum AlterTableType
 	AT_SetTableSpace,			/* SET TABLESPACE */
 	AT_SetRelOptions,			/* SET (...) -- AM specific parameters */
 	AT_ResetRelOptions,			/* RESET (...) -- AM specific parameters */
+	AT_ReplaceRelOptions,		/* replace reloption list in its entirety */
 	AT_EnableTrig,				/* ENABLE TRIGGER name */
 	AT_EnableAlwaysTrig,		/* ENABLE ALWAYS TRIGGER name */
 	AT_EnableReplicaTrig,		/* ENABLE REPLICA TRIGGER name */
@ -2277,6 +2279,7 @@ typedef struct ViewStmt
 	List	   *aliases;		/* target column names */
 	Node	   *query;			/* the SELECT query */
 	bool		replace;		/* replace an existing view? */
+	List	   *options;		/* options from WITH clause */
 } ViewStmt;

 /* ----------------------
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@ -195,6 +195,7 @@ typedef struct StdRdOptions
 	int32		vl_len_;		/* varlena header (do not touch directly!) */
 	int			fillfactor;		/* page fill factor in percent (0..100) */
 	AutoVacOpts autovacuum;		/* autovacuum-related options */
+	bool		security_barrier;	/* for views */
 } StdRdOptions;

 #define HEAP_MIN_FILLFACTOR			10
@ -222,6 +223,14 @@ typedef struct StdRdOptions
 #define RelationGetTargetPageFreeSpace(relation, defaultff) \
 	(BLCKSZ * (100 - RelationGetFillFactor(relation, defaultff)) / 100)

+/*
+ * RelationIsSecurityView
+ *		Returns whether the relation is security view, or not
+ */
+#define RelationIsSecurityView(relation)	\
+	((relation)->rd_options ?				\
+	 ((StdRdOptions *) (relation)->rd_options)->security_barrier : false)
+
 /*
 * RelationIsValid
 *		True iff relation descriptor is valid.
--- a/src/test/regress/expected/create_view.out
+++ b/src/test/regress/expected/create_view.out
@ -239,6 +239,55 @@ And relnamespace IN (SELECT OID FROM pg_namespace WHERE nspname LIKE 'pg_temp%')
     1
 (1 row)

+--
+-- CREATE VIEW and WITH(...) clause
+--
+CREATE VIEW mysecview1
+       AS SELECT * FROM tbl1 WHERE a = 0;
+CREATE VIEW mysecview2 WITH (security_barrier=true)
+       AS SELECT * FROM tbl1 WHERE a > 0;
+CREATE VIEW mysecview3 WITH (security_barrier=false)
+       AS SELECT * FROM tbl1 WHERE a < 0;
+CREATE VIEW mysecview4 WITH (security_barrier)
+       AS SELECT * FROM tbl1 WHERE a <> 0;
+CREATE VIEW mysecview5 WITH (security_barrier=100)	-- Error
+       AS SELECT * FROM tbl1 WHERE a > 100;
+ERROR:  invalid value for boolean option "security_barrier": 100
+CREATE VIEW mysecview6 WITH (invalid_option)		-- Error
+       AS SELECT * FROM tbl1 WHERE a < 100;
+ERROR:  unrecognized parameter "invalid_option"
+SELECT relname, relkind, reloptions FROM pg_class
+       WHERE oid in ('mysecview1'::regclass, 'mysecview2'::regclass,
+                     'mysecview3'::regclass, 'mysecview4'::regclass)
+       ORDER BY relname;
+  relname   | relkind |        reloptions        
+------------+---------+--------------------------
+ mysecview1 | v       | 
+ mysecview2 | v       | {security_barrier=true}
+ mysecview3 | v       | {security_barrier=false}
+ mysecview4 | v       | {security_barrier=true}
+(4 rows)
+
+CREATE OR REPLACE VIEW mysecview1
+       AS SELECT * FROM tbl1 WHERE a = 256;
+CREATE OR REPLACE VIEW mysecview2
+       AS SELECT * FROM tbl1 WHERE a > 256;
+CREATE OR REPLACE VIEW mysecview3 WITH (security_barrier=true)
+       AS SELECT * FROM tbl1 WHERE a < 256;
+CREATE OR REPLACE VIEW mysecview4 WITH (security_barrier=false)
+       AS SELECT * FROM tbl1 WHERE a <> 256;
+SELECT relname, relkind, reloptions FROM pg_class
+       WHERE oid in ('mysecview1'::regclass, 'mysecview2'::regclass,
+                     'mysecview3'::regclass, 'mysecview4'::regclass)
+       ORDER BY relname;
+  relname   | relkind |        reloptions        
+------------+---------+--------------------------
+ mysecview1 | v       | 
+ mysecview2 | v       | 
+ mysecview3 | v       | {security_barrier=true}
+ mysecview4 | v       | {security_barrier=false}
+(4 rows)
+
 DROP SCHEMA temp_view_test CASCADE;
 NOTICE:  drop cascades to 22 other objects
 DETAIL:  drop cascades to table temp_view_test.base_table
@ -264,7 +313,7 @@ drop cascades to view temp_view_test.v8
 drop cascades to sequence temp_view_test.seq1
 drop cascades to view temp_view_test.v9
 DROP SCHEMA testviewschm2 CASCADE;
-NOTICE:  drop cascades to 16 other objects
+NOTICE:  drop cascades to 20 other objects
 DETAIL:  drop cascades to table t1
 drop cascades to view temporal1
 drop cascades to view temporal2
@ -281,4 +330,8 @@ drop cascades to table tbl3
 drop cascades to table tbl4
 drop cascades to view mytempview
 drop cascades to view pubview
+drop cascades to view mysecview1
+drop cascades to view mysecview2
+drop cascades to view mysecview3
+drop cascades to view mysecview4
 SET search_path to public;
--- a/src/test/regress/sql/create_view.sql
+++ b/src/test/regress/sql/create_view.sql
@ -191,6 +191,39 @@ AND NOT EXISTS (SELECT g FROM tbl4 LEFT JOIN tmptbl ON tbl4.h = tmptbl.j);
 SELECT count(*) FROM pg_class where relname LIKE 'mytempview'
 And relnamespace IN (SELECT OID FROM pg_namespace WHERE nspname LIKE 'pg_temp%');

+--
+-- CREATE VIEW and WITH(...) clause
+--
+CREATE VIEW mysecview1
+       AS SELECT * FROM tbl1 WHERE a = 0;
+CREATE VIEW mysecview2 WITH (security_barrier=true)
+       AS SELECT * FROM tbl1 WHERE a > 0;
+CREATE VIEW mysecview3 WITH (security_barrier=false)
+       AS SELECT * FROM tbl1 WHERE a < 0;
+CREATE VIEW mysecview4 WITH (security_barrier)
+       AS SELECT * FROM tbl1 WHERE a <> 0;
+CREATE VIEW mysecview5 WITH (security_barrier=100)	-- Error
+       AS SELECT * FROM tbl1 WHERE a > 100;
+CREATE VIEW mysecview6 WITH (invalid_option)		-- Error
+       AS SELECT * FROM tbl1 WHERE a < 100;
+SELECT relname, relkind, reloptions FROM pg_class
+       WHERE oid in ('mysecview1'::regclass, 'mysecview2'::regclass,
+                     'mysecview3'::regclass, 'mysecview4'::regclass)
+       ORDER BY relname;
+
+CREATE OR REPLACE VIEW mysecview1
+       AS SELECT * FROM tbl1 WHERE a = 256;
+CREATE OR REPLACE VIEW mysecview2
+       AS SELECT * FROM tbl1 WHERE a > 256;
+CREATE OR REPLACE VIEW mysecview3 WITH (security_barrier=true)
+       AS SELECT * FROM tbl1 WHERE a < 256;
+CREATE OR REPLACE VIEW mysecview4 WITH (security_barrier=false)
+       AS SELECT * FROM tbl1 WHERE a <> 256;
+SELECT relname, relkind, reloptions FROM pg_class
+       WHERE oid in ('mysecview1'::regclass, 'mysecview2'::regclass,
+                     'mysecview3'::regclass, 'mysecview4'::regclass)
+       ORDER BY relname;
+
 DROP SCHEMA temp_view_test CASCADE;
 DROP SCHEMA testviewschm2 CASCADE;