Code cleanup of user name and user id handling in the backend. The current

user is now defined in terms of the user id, the user name is only computed
upon request (for display purposes). This is kind of the opposite of the
previous state, which would maintain the user name and compute the user id
for permission checks.

Besides perhaps saving a few cycles (integer vs string), this now creates a
single point of attack for changing the user id during a connection, for
purposes of "setuid" functions, etc.

1 files changed, 39 insertions, 38 deletions

diff --git a/src/backend/catalog/aclchk.c b/src/backend/catalog/aclchk.c
index 6be489a0c7..b5c9cf51a1 100644
--- a/src/backend/catalog/aclchk.c
+++ b/src/backend/catalog/aclchk.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/aclchk.c,v 1.39 2000/07/31 22:39:13 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/aclchk.c,v 1.40 2000/09/06 14:15:15 petere Exp $
  *
  * NOTES
  *	  See acl.h.
@@ -355,21 +355,22 @@ aclcheck(char *relname, Acl *acl, AclId id, AclIdType idtype, AclMode mode)
 }
 
 int32
-pg_aclcheck(char *relname, char *usename, AclMode mode)
+pg_aclcheck(char *relname, Oid userid, AclMode mode)
 {
 	HeapTuple	tuple;
-	AclId		id;
 	Acl		   *acl = (Acl *) NULL;
 	int32		result;
+	char       *usename;
 	Relation	relation;
 
-	tuple = SearchSysCacheTuple(SHADOWNAME,
-								PointerGetDatum(usename),
+	tuple = SearchSysCacheTuple(SHADOWSYSID,
+								ObjectIdGetDatum(userid),
 								0, 0, 0);
 	if (!HeapTupleIsValid(tuple))
-		elog(ERROR, "pg_aclcheck: user \"%s\" not found",
-			 usename);
-	id = (AclId) ((Form_pg_shadow) GETSTRUCT(tuple))->usesysid;
+		elog(ERROR, "pg_aclcheck: invalid user id %u",
+			 (unsigned) userid);
+
+	usename = NameStr(((Form_pg_shadow) GETSTRUCT(tuple))->usename);
 
 	/*
 	 * Deny anyone permission to update a system catalog unless
@@ -445,28 +446,28 @@ pg_aclcheck(char *relname, char *usename, AclMode mode)
 	}
 	heap_close(relation, RowExclusiveLock);
 #endif
-	result = aclcheck(relname, acl, id, (AclIdType) ACL_IDTYPE_UID, mode);
+	result = aclcheck(relname, acl, userid, (AclIdType) ACL_IDTYPE_UID, mode);
 	if (acl)
 		pfree(acl);
 	return result;
 }
 
 int32
-pg_ownercheck(const char *usename,
+pg_ownercheck(Oid userid,
 			  const char *value,
 			  int cacheid)
 {
 	HeapTuple	tuple;
-	AclId		user_id,
-				owner_id = 0;
+	AclId		owner_id = 0;
+	char       *usename;
 
-	tuple = SearchSysCacheTuple(SHADOWNAME,
-								PointerGetDatum(usename),
+	tuple = SearchSysCacheTuple(SHADOWSYSID,
+								ObjectIdGetDatum(userid),
 								0, 0, 0);
 	if (!HeapTupleIsValid(tuple))
-		elog(ERROR, "pg_ownercheck: user \"%s\" not found",
-			 usename);
-	user_id = (AclId) ((Form_pg_shadow) GETSTRUCT(tuple))->usesysid;
+		elog(ERROR, "pg_ownercheck: invalid user id %u",
+			 (unsigned) userid);
+	usename = NameStr(((Form_pg_shadow) GETSTRUCT(tuple))->usename);
 
 	/*
 	 * Superusers bypass all permission-checking.
@@ -513,26 +514,26 @@ pg_ownercheck(const char *usename,
 			break;
 	}
 
-	return user_id == owner_id;
+	return userid == owner_id;
 }
 
 int32
-pg_func_ownercheck(char *usename,
+pg_func_ownercheck(Oid userid,
 				   char *funcname,
 				   int nargs,
 				   Oid *arglist)
 {
 	HeapTuple	tuple;
-	AclId		user_id,
-				owner_id;
+	AclId		owner_id;
+	char *username;
 
-	tuple = SearchSysCacheTuple(SHADOWNAME,
-								PointerGetDatum(usename),
+	tuple = SearchSysCacheTuple(SHADOWSYSID,
+								ObjectIdGetDatum(userid),
 								0, 0, 0);
 	if (!HeapTupleIsValid(tuple))
-		elog(ERROR, "pg_func_ownercheck: user \"%s\" not found",
-			 usename);
-	user_id = (AclId) ((Form_pg_shadow) GETSTRUCT(tuple))->usesysid;
+		elog(ERROR, "pg_func_ownercheck: invalid user id %u",
+			 (unsigned) userid);
+	username = NameStr(((Form_pg_shadow) GETSTRUCT(tuple))->usename);
 
 	/*
 	 * Superusers bypass all permission-checking.
@@ -541,7 +542,7 @@ pg_func_ownercheck(char *usename,
 	{
 #ifdef ACLDEBUG_TRACE
 		elog(DEBUG, "pg_ownercheck: user \"%s\" is superuser",
-			 usename);
+			 username);
 #endif
 		return 1;
 	}
@@ -556,25 +557,25 @@ pg_func_ownercheck(char *usename,
 
 	owner_id = ((Form_pg_proc) GETSTRUCT(tuple))->proowner;
 
-	return user_id == owner_id;
+	return userid == owner_id;
 }
 
 int32
-pg_aggr_ownercheck(char *usename,
+pg_aggr_ownercheck(Oid userid,
 				   char *aggname,
 				   Oid basetypeID)
 {
 	HeapTuple	tuple;
-	AclId		user_id,
-				owner_id;
+	AclId		owner_id;
+	char *username;
 
-	tuple = SearchSysCacheTuple(SHADOWNAME,
-								PointerGetDatum(usename),
+	tuple = SearchSysCacheTuple(SHADOWSYSID,
+								PointerGetDatum(userid),
 								0, 0, 0);
 	if (!HeapTupleIsValid(tuple))
-		elog(ERROR, "pg_aggr_ownercheck: user \"%s\" not found",
-			 usename);
-	user_id = (AclId) ((Form_pg_shadow) GETSTRUCT(tuple))->usesysid;
+		elog(ERROR, "pg_aggr_ownercheck: invalid user id %u",
+			 (unsigned) userid);
+	username = NameStr(((Form_pg_shadow) GETSTRUCT(tuple))->usename);
 
 	/*
 	 * Superusers bypass all permission-checking.
@@ -583,7 +584,7 @@ pg_aggr_ownercheck(char *usename,
 	{
 #ifdef ACLDEBUG_TRACE
 		elog(DEBUG, "pg_aggr_ownercheck: user \"%s\" is superuser",
-			 usename);
+			 username);
 #endif
 		return 1;
 	}
@@ -598,5 +599,5 @@ pg_aggr_ownercheck(char *usename,
 
 	owner_id = ((Form_pg_aggregate) GETSTRUCT(tuple))->aggowner;
 
-	return user_id == owner_id;
+	return userid == owner_id;
 }