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.

2 files changed, 69 insertions, 23 deletions

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 8473c9e7f44..4953def029b 100644
--- 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);
 
diff --git a/src/backend/commands/view.c b/src/backend/commands/view.c
index b2381996586..3edcd33eaf4 100644
--- 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 ...
@@ -204,20 +207,26 @@ DefineVirtualRelation(const RangeVar *relation, List *tlist, bool replace,
 		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
 		 * TABLE ADD COLUMN infrastructure for this.
 		 */
 		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