A fix and a test case for Bug#34166 Server crash in SHOW OPEN TABLES and

pre-locking.

The crash was caused by an implicit assumption in check_table_access() that
table_list parameter is always a part of lex->query_tables.

When iterating over the passed list of tables, check_table_access() used
to stop only when lex->query_tables_last_not_own was reached. 
In case of pre-locking, lex->query_tables_last_own is not NULL and points
to some element of lex->query_tables. When the parameter
of check_table_access() was not part of lex->query_tables, loop invariant
could never be violated and a crash would happen when the current table
pointer would point beyond the end of the provided list.

The fix is to change the signature of check_table_access() to also accept
a numeric limit of loop iterations, similarly to check_grant(), and 
supply this limit in all places when we want to check access of tables
that are outside lex->query_tables, or just want to check access to one table.


mysql-test/r/information_schema.result:
  Update test results (Bug#34166).
mysql-test/t/information_schema.test:
  Add a test case for Bug#34166.
sql/mysql_priv.h:
  Change signature of check_table_access() to accept a numeric limit
  of tables to check.
sql/sp_head.cc:
  Update to the new signature of check_table_access().
sql/sql_acl.cc:
  Improve code clarity: if there is a numeric limit, we should not need
  to look at first_not_own_table.
sql/sql_base.cc:
  Update to the new signature of check_table_access().
sql/sql_cache.cc:
  Update to the new signature of check_table_access().
sql/sql_parse.cc:
  Update to the new signature of check_table_access().
  Change check_table_access() to accept an optional numeric limit of tables
  to check. A crash would happen when check_table_access() was
  passed a list of tables that is not part of lex->query_tables and
  lex->query_tables_last_own was not NULL.
sql/sql_plugin.cc:
  Update to the new signature of check_table_access().
sql/sql_prepare.cc:
  Update to the new signature of check_table_access().
sql/sql_show.cc:
  Update to the new signature of check_table_access().
  Ensure that check_table_access() only checks access to the first
  table in the table list when called from list_open_tables().
  list_open_tables() supplies a table list that is created on stack,
  whereas check_table_access() used to assume that the supplied list is a part
  of thd->lex.
sql/sql_trigger.cc:
  Update to the new signature of check_table_access().
sql/sql_view.cc:
  Update to the new signature of check_table_access().

mysql-test/r/information_schema.result

@@ -1619,4 +1619,19 @@ Db	Name	Definer	Time zone	Type	Execute at	Interval value	Interval field	Starts	E
 show events where Db= 'information_schema';
 Db	Name	Definer	Time zone	Type	Execute at	Interval value	Interval field	Starts	Ends	Status	Originator	character_set_client	collation_connection	Database Collation
 use test;
+#
+# Bug#34166: Server crash in SHOW OPEN TABLES and prelocking
+#
+drop table if exists t1;
+drop function if exists f1;
+create table t1 (a int);
+create function f1() returns int
+begin
+insert into t1 (a) values (1);
+return 0;
+end|
+show open tables where f1()=0;
+show open tables where f1()=0;
+drop table t1;
+drop function f1;
 End of 5.1 tests.

mysql-test/t/information_schema.test

@@ -1248,4 +1248,26 @@ show events from information_schema;
 show events where Db= 'information_schema';
 use test;
 
+--echo #
+--echo # Bug#34166: Server crash in SHOW OPEN TABLES and prelocking
+--echo #
+--disable_warnings
+drop table if exists t1;
+drop function if exists f1;
+--enable_warnings
+create table t1 (a int);
+delimiter |;
+create function f1() returns int
+begin
+  insert into t1 (a) values (1);
+  return 0;
+end|
+delimiter ;|
+--disable_result_log
+show open tables where f1()=0;
+show open tables where f1()=0;
+--enable_result_log
+drop table t1;
+drop function f1;
+
 --echo End of 5.1 tests.

sql/mysql_priv.h

@@ -1015,7 +1015,7 @@ bool reload_acl_and_cache(THD *thd, ulong options, TABLE_LIST *tables,
 bool check_access(THD *thd, ulong access, const char *db, ulong *save_priv,
 		  bool no_grant, bool no_errors, bool schema_db);
 bool check_table_access(THD *thd, ulong want_access, TABLE_LIST *tables,
-			bool no_errors);
+			uint number, bool no_errors);
 bool check_global_access(THD *thd, ulong want_access);
 #else
 inline bool check_access(THD *thd, ulong access, const char *db,
@@ -1027,7 +1027,7 @@ inline bool check_access(THD *thd, ulong access, const char *db,
   return false;
 }
 inline bool check_table_access(THD *thd, ulong want_access, TABLE_LIST *tables,
-			bool no_errors)
+			uint number, bool no_errors)
 { return false; }
 inline bool check_global_access(THD *thd, ulong want_access)
 { return false; }

sql/sp_head.cc

@@ -2265,7 +2265,7 @@ bool check_show_routine_access(THD *thd, sp_head *sp, bool *full_access)
   bzero((char*) &tables,sizeof(tables));
   tables.db= (char*) "mysql";
   tables.table_name= tables.alias= (char*) "proc";
-  *full_access= (!check_table_access(thd, SELECT_ACL, &tables, 1) ||
+  *full_access= (!check_table_access(thd, SELECT_ACL, &tables, 1, TRUE) ||
                  (!strcmp(sp->m_definer_user.str,
                           thd->security_ctx->priv_user) &&
                   !strcmp(sp->m_definer_host.str,
@@ -2712,7 +2712,7 @@ int sp_instr::exec_open_and_lock_tables(THD *thd, TABLE_LIST *tables)
     Check whenever we have access to tables for this statement
     and open and lock them before executing instructions core function.
   */
-  if (check_table_access(thd, SELECT_ACL, tables, 0)
+  if (check_table_access(thd, SELECT_ACL, tables, UINT_MAX, FALSE)
       || open_and_lock_tables(thd, tables))
     result= -1;
   else

sql/sql_acl.cc

@@ -3862,7 +3862,7 @@ bool check_grant(THD *thd, ulong want_access, TABLE_LIST *tables,
     of other queries). For simple queries first_not_own_table is 0.
   */
   for (i= 0, table= tables;
-       table != first_not_own_table && i < number;
+       i < number  && table != first_not_own_table;
        table= table->next_global, i++)
   {
     /* Remove SHOW_VIEW_ACL, because it will be checked during making view */

sql/sql_base.cc

@@ -799,7 +799,7 @@ OPEN_TABLE_LIST *list_open_tables(THD *thd, const char *db, const char *wild)
     table_list.table_name= share->table_name.str;
     table_list.grant.privilege=0;
 
-    if (check_table_access(thd,SELECT_ACL | EXTRA_ACL,&table_list,1))
+    if (check_table_access(thd,SELECT_ACL | EXTRA_ACL,&table_list, 1, TRUE))
       continue;
     /* need to check if we haven't already listed it */
     for (table= open_list  ; table ; table=table->next)

sql/sql_cache.cc

@@ -1378,7 +1378,7 @@ def_week_frmt: %lu",
     table_list.db = table->db();
     table_list.alias= table_list.table_name= table->table();
 #ifndef NO_EMBEDDED_ACCESS_CHECKS
-    if (check_table_access(thd,SELECT_ACL,&table_list,1))
+    if (check_table_access(thd,SELECT_ACL,&table_list, 1, TRUE))
     {
       DBUG_PRINT("qcache",
 		 ("probably no SELECT access to %s.%s =>  return to normal processing",

sql/sql_plugin.cc

@@ -1619,7 +1619,7 @@ bool mysql_install_plugin(THD *thd, const LEX_STRING *name, const LEX_STRING *dl
   bzero(&tables, sizeof(tables));
   tables.db= (char *)"mysql";
   tables.table_name= tables.alias= (char *)"plugin";
-  if (check_table_access(thd, INSERT_ACL, &tables, 0))
+  if (check_table_access(thd, INSERT_ACL, &tables, 1, FALSE))
     DBUG_RETURN(TRUE);
 
   /* need to open before acquiring LOCK_plugin or it will deadlock */

sql/sql_prepare.cc

@@ -1272,7 +1272,7 @@ static int mysql_test_select(Prepared_statement *stmt,
   ulong privilege= lex->exchange ? SELECT_ACL | FILE_ACL : SELECT_ACL;
   if (tables)
   {
-    if (check_table_access(thd, privilege, tables,0))
+    if (check_table_access(thd, privilege, tables, UINT_MAX, FALSE))
       goto error;
   }
   else if (check_access(thd, privilege, any_db,0,0,0,0))
@@ -1342,7 +1342,7 @@ static bool mysql_test_do_fields(Prepared_statement *stmt,
   THD *thd= stmt->thd;
 
   DBUG_ENTER("mysql_test_do_fields");
-  if (tables && check_table_access(thd, SELECT_ACL, tables, 0))
+  if (tables && check_table_access(thd, SELECT_ACL, tables, UINT_MAX, FALSE))
     DBUG_RETURN(TRUE);
 
   if (open_normal_and_derived_tables(thd, tables, 0))
@@ -1374,7 +1374,7 @@ static bool mysql_test_set_fields(Prepared_statement *stmt,
   THD *thd= stmt->thd;
   set_var_base *var;
 
-  if (tables && check_table_access(thd, SELECT_ACL, tables, 0) ||
+  if (tables && check_table_access(thd, SELECT_ACL, tables, UINT_MAX, FALSE) ||
       open_normal_and_derived_tables(thd, tables, 0))
     goto error;
 

sql/sql_show.cc

@@ -4059,7 +4059,7 @@ int fill_schema_proc(THD *thd, TABLE_LIST *tables, COND *cond)
   proc_tables.table_name= proc_tables.alias= (char*) "proc";
   proc_tables.table_name_length= 4;
   proc_tables.lock_type= TL_READ;
-  full_access= !check_table_access(thd, SELECT_ACL, &proc_tables, 1);
+  full_access= !check_table_access(thd, SELECT_ACL, &proc_tables, 1, TRUE);
   if (!(proc_table= open_proc_table_for_read(thd, &open_tables_state_backup)))
   {
     DBUG_RETURN(1);
@@ -4447,10 +4447,8 @@ static int get_schema_triggers_record(THD *thd, TABLE_LIST *tables,
     Table_triggers_list *triggers= tables->table->triggers;
     int event, timing;
 
-#ifndef NO_EMBEDDED_ACCESS_CHECKS
-    if (check_table_access(thd, TRIGGER_ACL, tables, 1))
+    if (check_table_access(thd, TRIGGER_ACL, tables, 1, TRUE))
       goto ret;
-#endif
 
     for (event= 0; event < (int)TRG_EVENT_MAX; event++)
     {

sql/sql_trigger.cc

@@ -418,7 +418,7 @@ bool mysql_create_or_drop_trigger(THD *thd, TABLE_LIST *tables, bool create)
     TABLE_LIST **save_query_tables_own_last= thd->lex->query_tables_own_last;
     thd->lex->query_tables_own_last= 0;
 
-    err_status= check_table_access(thd, TRIGGER_ACL, tables, 0);
+    err_status= check_table_access(thd, TRIGGER_ACL, tables, 1, FALSE);
 
     thd->lex->query_tables_own_last= save_query_tables_own_last;
 

sql/sql_view.cc

@@ -1123,8 +1123,8 @@ bool mysql_make_view(THD *thd, File_parser *parser, TABLE_LIST *table,
     if (!table->prelocking_placeholder &&
         (old_lex->sql_command == SQLCOM_SELECT && old_lex->describe))
     {
-      if (check_table_access(thd, SELECT_ACL, view_tables, 1) &&
-          check_table_access(thd, SHOW_VIEW_ACL, table, 1))
+      if (check_table_access(thd, SELECT_ACL, view_tables, UINT_MAX, TRUE) &&
+          check_table_access(thd, SHOW_VIEW_ACL, table, UINT_MAX, TRUE))
       {
         my_message(ER_VIEW_NO_EXPLAIN, ER(ER_VIEW_NO_EXPLAIN), MYF(0));
         goto err;
@@ -1134,7 +1134,7 @@ bool mysql_make_view(THD *thd, File_parser *parser, TABLE_LIST *table,
              (old_lex->sql_command == SQLCOM_SHOW_CREATE) &&
              !table->belong_to_view)
     {
-      if (check_table_access(thd, SHOW_VIEW_ACL, table, 0))
+      if (check_table_access(thd, SHOW_VIEW_ACL, table, UINT_MAX, FALSE))
         goto err;
     }