1 files changed, 51 insertions, 2 deletions

diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 292ba8d9b6f..7652dc854e6 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -49,6 +49,7 @@
 #include "utils/acl.h"
 #include "utils/builtins.h"
 #include "utils/fmgroids.h"
+#include "utils/guc.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
@@ -344,8 +345,13 @@ DefineIndex(Oid relationId,
 	LOCKTAG		heaplocktag;
 	LOCKMODE	lockmode;
 	Snapshot	snapshot;
+	Oid			root_save_userid;
+	int			root_save_sec_context;
+	int			root_save_nestlevel;
 	int			i;
 
+	root_save_nestlevel = NewGUCNestLevel();
+
 	/*
 	 * Force non-concurrent build on temporary relations, even if CONCURRENTLY
 	 * was requested.  Other backends can't access a temporary relation, so
@@ -386,6 +392,15 @@ DefineIndex(Oid relationId,
 	lockmode = concurrent ? ShareUpdateExclusiveLock : ShareLock;
 	rel = heap_open(relationId, lockmode);
 
+	/*
+	 * Switch to the table owner's userid, so that any index functions are run
+	 * as that user.  Also lock down security-restricted operations.  We
+	 * already arranged to make GUC variable changes local to this command.
+	 */
+	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
+	SetUserIdAndSecContext(rel->rd_rel->relowner,
+						   root_save_sec_context | SECURITY_RESTRICTED_OPERATION);
+
 	relationId = RelationGetRelid(rel);
 	namespaceId = RelationGetNamespace(rel);
 
@@ -441,7 +456,7 @@ DefineIndex(Oid relationId,
 	{
 		AclResult	aclresult;
 
-		aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
+		aclresult = pg_namespace_aclcheck(namespaceId, root_save_userid,
 										  ACL_CREATE);
 		if (aclresult != ACLCHECK_OK)
 			aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
@@ -468,7 +483,7 @@ DefineIndex(Oid relationId,
 	{
 		AclResult	aclresult;
 
-		aclresult = pg_tablespace_aclcheck(tablespaceId, GetUserId(),
+		aclresult = pg_tablespace_aclcheck(tablespaceId, root_save_userid,
 										   ACL_CREATE);
 		if (aclresult != ACLCHECK_OK)
 			aclcheck_error(aclresult, ACL_KIND_TABLESPACE,
@@ -695,15 +710,33 @@ DefineIndex(Oid relationId,
 
 	if (!OidIsValid(indexRelationId))
 	{
+		/* Roll back any GUC changes executed by index functions. */
+		AtEOXact_GUC(false, root_save_nestlevel);
+
+		/* Restore userid and security context */
+		SetUserIdAndSecContext(root_save_userid, root_save_sec_context);
+
 		heap_close(rel, NoLock);
 		return address;
 	}
 
+	/*
+	 * Roll back any GUC changes executed by index functions, and keep
+	 * subsequent changes local to this command.  It's barely possible that
+	 * some index function changed a behavior-affecting GUC, e.g. xmloption,
+	 * that affects subsequent steps.
+	 */
+	AtEOXact_GUC(false, root_save_nestlevel);
+	root_save_nestlevel = NewGUCNestLevel();
+
 	/* Add any requested comment */
 	if (stmt->idxcomment != NULL)
 		CreateComments(indexRelationId, RelationRelationId, 0,
 					   stmt->idxcomment);
 
+	AtEOXact_GUC(false, root_save_nestlevel);
+	SetUserIdAndSecContext(root_save_userid, root_save_sec_context);
+
 	if (!concurrent)
 	{
 		/* Close the heap and we're done, in the non-concurrent case */
@@ -782,6 +815,16 @@ DefineIndex(Oid relationId,
 	/* Open and lock the parent heap relation */
 	rel = heap_openrv(stmt->relation, ShareUpdateExclusiveLock);
 
+	/*
+	 * Switch to the table owner's userid, so that any index functions are run
+	 * as that user.  Also lock down security-restricted operations and
+	 * arrange to make GUC variable changes local to this command.
+	 */
+	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
+	SetUserIdAndSecContext(rel->rd_rel->relowner,
+						   root_save_sec_context | SECURITY_RESTRICTED_OPERATION);
+	root_save_nestlevel = NewGUCNestLevel();
+
 	/* And the target index relation */
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -797,6 +840,12 @@ DefineIndex(Oid relationId,
 	/* Now build the index */
 	index_build(rel, indexRelation, indexInfo, stmt->primary, false);
 
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, root_save_nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(root_save_userid, root_save_sec_context);
+
 	/* Close both the relations, but keep the locks */
 	heap_close(rel, NoLock);
 	index_close(indexRelation, NoLock);