Add a SET option to the GRANT command.

Similar to how the INHERIT option controls whether or not the
permissions of the granted role are automatically available to the
grantee, the new SET permission controls whether or not the grantee
may use the SET ROLE command to assume the privileges of the granted
role.

In addition, the new SET permission controls whether or not it
is possible to transfer ownership of objects to the target role
or to create new objects owned by the target role using commands
such as CREATE DATABASE .. OWNER. We could alternatively have made
this controlled by the INHERIT option, or allow it when either
option is given. An advantage of this approach is that if you
are granted a predefined role with INHERIT TRUE, SET FALSE, you
can't go and create objects owned by that role.

The underlying theory here is that the ability to create objects
as a target role is not a privilege per se, and thus does not
depend on whether you inherit the target role's privileges. However,
it's surely something you could do anyway if you could SET ROLE
to the target role, and thus making it contingent on whether you
have that ability is reasonable.

Design review by Nathan Bossat, Wolfgang Walther, Jeff Davis,
Peter Eisentraut, and Stephen Frost.

Discussion: http://postgr.es/m/CA+Tgmob+zDSRS6JXYrgq0NWdzCXuTNzT5eK54Dn2hhgt17nm8A@mail.gmail.com

9 files changed, 51 insertions, 13 deletions

diff --git a/src/backend/commands/alter.c b/src/backend/commands/alter.c
index b2089d785b6..10b6fe19a2c 100644
--- a/src/backend/commands/alter.c
+++ b/src/backend/commands/alter.c
@@ -999,7 +999,7 @@ AlterObjectOwner_internal(Relation rel, Oid objectId, Oid new_ownerId)
 							   objname);
 			}
 			/* Must be able to become new owner */
-			check_is_member_of_role(GetUserId(), new_ownerId);
+			check_can_set_role(GetUserId(), new_ownerId);
 
 			/* New owner must have CREATE privilege on namespace */
 			if (OidIsValid(namespaceId))
diff --git a/src/backend/commands/dbcommands.c b/src/backend/commands/dbcommands.c
index a67ea86619c..6eb87427181 100644
--- a/src/backend/commands/dbcommands.c
+++ b/src/backend/commands/dbcommands.c
@@ -941,7 +941,7 @@ createdb(ParseState *pstate, const CreatedbStmt *stmt)
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 				 errmsg("permission denied to create database")));
 
-	check_is_member_of_role(GetUserId(), datdba);
+	check_can_set_role(GetUserId(), datdba);
 
 	/*
 	 * Lookup database (template) to be cloned, and obtain share lock on it.
@@ -2495,7 +2495,7 @@ AlterDatabaseOwner(const char *dbname, Oid newOwnerId)
 						   dbname);
 
 		/* Must be able to become new owner */
-		check_is_member_of_role(GetUserId(), newOwnerId);
+		check_can_set_role(GetUserId(), newOwnerId);
 
 		/*
 		 * must have createdb rights
diff --git a/src/backend/commands/foreigncmds.c b/src/backend/commands/foreigncmds.c
index 55b0be9e1d1..28b5c75f110 100644
--- a/src/backend/commands/foreigncmds.c
+++ b/src/backend/commands/foreigncmds.c
@@ -363,7 +363,7 @@ AlterForeignServerOwner_internal(Relation rel, HeapTuple tup, Oid newOwnerId)
 							   NameStr(form->srvname));
 
 			/* Must be able to become new owner */
-			check_is_member_of_role(GetUserId(), newOwnerId);
+			check_can_set_role(GetUserId(), newOwnerId);
 
 			/* New owner must have USAGE privilege on foreign-data wrapper */
 			aclresult = object_aclcheck(ForeignDataWrapperRelationId, form->srvfdw, newOwnerId, ACL_USAGE);
diff --git a/src/backend/commands/publicationcmds.c b/src/backend/commands/publicationcmds.c
index 940655b9be0..20fa72c5c80 100644
--- a/src/backend/commands/publicationcmds.c
+++ b/src/backend/commands/publicationcmds.c
@@ -1911,7 +1911,7 @@ AlterPublicationOwner_internal(Relation rel, HeapTuple tup, Oid newOwnerId)
 						   NameStr(form->pubname));
 
 		/* Must be able to become new owner */
-		check_is_member_of_role(GetUserId(), newOwnerId);
+		check_can_set_role(GetUserId(), newOwnerId);
 
 		/* New owner must have CREATE privilege on database */
 		aclresult = object_aclcheck(DatabaseRelationId, MyDatabaseId, newOwnerId, ACL_CREATE);
diff --git a/src/backend/commands/schemacmds.c b/src/backend/commands/schemacmds.c
index b03f07a2322..12cbfba7d06 100644
--- a/src/backend/commands/schemacmds.c
+++ b/src/backend/commands/schemacmds.c
@@ -97,7 +97,7 @@ CreateSchemaCommand(CreateSchemaStmt *stmt, const char *queryString,
 		aclcheck_error(aclresult, OBJECT_DATABASE,
 					   get_database_name(MyDatabaseId));
 
-	check_is_member_of_role(saved_uid, owner_uid);
+	check_can_set_role(saved_uid, owner_uid);
 
 	/* Additional check to protect reserved schema names */
 	if (!allowSystemTableMods && IsReservedName(schemaName))
@@ -370,7 +370,7 @@ AlterSchemaOwner_internal(HeapTuple tup, Relation rel, Oid newOwnerId)
 						   NameStr(nspForm->nspname));
 
 		/* Must be able to become new owner */
-		check_is_member_of_role(GetUserId(), newOwnerId);
+		check_can_set_role(GetUserId(), newOwnerId);
 
 		/*
 		 * must have create-schema rights
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index f0068078520..845208d662b 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -13833,7 +13833,7 @@ ATExecChangeOwner(Oid relationOid, Oid newOwnerId, bool recursing, LOCKMODE lock
 								   RelationGetRelationName(target_rel));
 
 				/* Must be able to become new owner */
-				check_is_member_of_role(GetUserId(), newOwnerId);
+				check_can_set_role(GetUserId(), newOwnerId);
 
 				/* New owner must have CREATE privilege on namespace */
 				aclresult = object_aclcheck(NamespaceRelationId, namespaceOid, newOwnerId,
diff --git a/src/backend/commands/typecmds.c b/src/backend/commands/typecmds.c
index ecc8b3f44c9..7770a86bee0 100644
--- a/src/backend/commands/typecmds.c
+++ b/src/backend/commands/typecmds.c
@@ -3745,7 +3745,7 @@ AlterTypeOwner(List *names, Oid newOwnerId, ObjectType objecttype)
 				aclcheck_error_type(ACLCHECK_NOT_OWNER, typTup->oid);
 
 			/* Must be able to become new owner */
-			check_is_member_of_role(GetUserId(), newOwnerId);
+			check_can_set_role(GetUserId(), newOwnerId);
 
 			/* New owner must have CREATE privilege on namespace */
 			aclresult = object_aclcheck(NamespaceRelationId, typTup->typnamespace,
diff --git a/src/backend/commands/user.c b/src/backend/commands/user.c
index 2369cc600c7..8b6543edee2 100644
--- a/src/backend/commands/user.c
+++ b/src/backend/commands/user.c
@@ -51,8 +51,8 @@
  * RRG_REMOVE_ADMIN_OPTION indicates a grant that would need to have
  * admin_option set to false by the operation.
  *
- * RRG_REMOVE_INHERIT_OPTION indicates a grant that would need to have
- * inherit_option set to false by the operation.
+ * Similarly, RRG_REMOVE_INHERIT_OPTION and RRG_REMOVE_SET_OPTION indicate
+ * grants that would need to have the corresponding options set to false.
  *
  * RRG_DELETE_GRANT indicates a grant that would need to be removed entirely
  * by the operation.
@@ -62,6 +62,7 @@ typedef enum
 	RRG_NOOP,
 	RRG_REMOVE_ADMIN_OPTION,
 	RRG_REMOVE_INHERIT_OPTION,
+	RRG_REMOVE_SET_OPTION,
 	RRG_DELETE_GRANT
 } RevokeRoleGrantAction;
 
@@ -73,10 +74,12 @@ typedef struct
 	unsigned	specified;
 	bool		admin;
 	bool		inherit;
+	bool		set;
 } GrantRoleOptions;
 
 #define GRANT_ROLE_SPECIFIED_ADMIN			0x0001
 #define GRANT_ROLE_SPECIFIED_INHERIT		0x0002
+#define GRANT_ROLE_SPECIFIED_SET			0x0004
 
 /* GUC parameter */
 int			Password_encryption = PASSWORD_TYPE_SCRAM_SHA_256;
@@ -1389,6 +1392,12 @@ GrantRole(ParseState *pstate, GrantRoleStmt *stmt)
 			if (parse_bool(optval, &popt.inherit))
 				continue;
 		}
+		else if (strcmp(opt->defname, "set") == 0)
+		{
+			popt.specified |= GRANT_ROLE_SPECIFIED_SET;
+			if (parse_bool(optval, &popt.set))
+				continue;
+		}
 		else
 			ereport(ERROR,
 					errcode(ERRCODE_SYNTAX_ERROR),
@@ -1776,6 +1785,16 @@ AddRoleMems(const char *rolename, Oid roleid,
 				at_least_one_change = true;
 			}
 
+			if ((popt->specified & GRANT_ROLE_SPECIFIED_SET) != 0
+				&& authmem_form->set_option != popt->set)
+			{
+				new_record[Anum_pg_auth_members_set_option - 1] =
+					BoolGetDatum(popt->set);
+				new_record_repl[Anum_pg_auth_members_set_option - 1] =
+					true;
+				at_least_one_change = true;
+			}
+
 			if (!at_least_one_change)
 			{
 				ereport(NOTICE,
@@ -1798,9 +1817,15 @@ AddRoleMems(const char *rolename, Oid roleid,
 			Oid			objectId;
 			Oid		   *newmembers = palloc(sizeof(Oid));
 
-			/* Set admin option if user set it to true, otherwise not. */
+			/*
+			 * The values for these options can be taken directly from 'popt'.
+			 * Either they were specified, or the defaults as set by
+			 * InitGrantRoleOptions are correct.
+			 */
 			new_record[Anum_pg_auth_members_admin_option - 1] =
 				BoolGetDatum(popt->admin);
+			new_record[Anum_pg_auth_members_set_option - 1] =
+				BoolGetDatum(popt->set);
 
 			/*
 			 * If the user specified a value for the inherit option, use
@@ -1989,6 +2014,13 @@ DelRoleMems(const char *rolename, Oid roleid,
 				new_record_repl[Anum_pg_auth_members_inherit_option - 1] =
 					true;
 			}
+			else if (actions[i] == RRG_REMOVE_SET_OPTION)
+			{
+				new_record[Anum_pg_auth_members_set_option - 1] =
+					BoolGetDatum(false);
+				new_record_repl[Anum_pg_auth_members_set_option - 1] =
+					true;
+			}
 			else
 				elog(ERROR, "unknown role revoke action");
 
@@ -2182,6 +2214,11 @@ plan_single_revoke(CatCList *memlist, RevokeRoleGrantAction *actions,
 				 */
 				actions[i] = RRG_REMOVE_INHERIT_OPTION;
 			}
+			else if ((popt->specified & GRANT_ROLE_SPECIFIED_SET) != 0)
+			{
+				/* Here too, no need to recurse. */
+				actions[i] = RRG_REMOVE_SET_OPTION;
+			}
 			else
 			{
 				bool	revoke_admin_option_only;
@@ -2331,4 +2368,5 @@ InitGrantRoleOptions(GrantRoleOptions *popt)
 	popt->specified = 0;
 	popt->admin = false;
 	popt->inherit = false;
+	popt->set = true;
 }
diff --git a/src/backend/commands/variable.c b/src/backend/commands/variable.c
index 791bac6715c..00d8d54d820 100644
--- a/src/backend/commands/variable.c
+++ b/src/backend/commands/variable.c
@@ -939,7 +939,7 @@ check_role(char **newval, void **extra, GucSource source)
 		 * leader's state.
 		 */
 		if (!InitializingParallelWorker &&
-			!is_member_of_role(GetSessionUserId(), roleid))
+			!member_can_set_role(GetSessionUserId(), roleid))
 		{
 			if (source == PGC_S_TEST)
 			{