Commit e9452db1 authored by unknown's avatar unknown

Fix for bug#19634 "Re-execution of multi-delete which involve trigger/stored

function crashes server".

Attempts to execute prepared multi-delete statement which involved trigger or
stored function caused server crashes (the same happened for such statements
included in stored procedures in cases when one tried to execute them more
than once).

The problem was caused by yet another incorrect usage of check_table_access()
routine (the latter assumes that table list which it gets as argument
corresponds to value LEX::query_tables_own_last). We solve this problem by
juggling with LEX::query_tables_own_last value when we call
check_table_access() for LEX::auxilliary_table_list (better solution is too
intrusive and should be done in 5.1).


mysql-test/r/sp-prelocking.result:
  Added test for bug#19634 "Re-execution of multi-delete which involve trigger/
  stored function crashes server".
mysql-test/t/sp-prelocking.test:
  Added test for bug#19634 "Re-execution of multi-delete which involve trigger/
  stored function crashes server".
sql/sql_parse.cc:
  To call safely check_table_access() for LEX::auxilliary_table_list we have
  to juggle with LEX::query_tables_own_last value.
parent 375a1894
......@@ -237,3 +237,21 @@ deallocate prepare stmt;
drop table t1;
drop view v1, v2, v3;
drop function bug15683;
drop table if exists t1, t2, t3;
drop function if exists bug19634;
create table t1 (id int, data int);
create table t2 (id int);
create table t3 (data int);
create function bug19634() returns int return (select count(*) from t3);
prepare stmt from "delete t1 from t1, t2 where t1.id = t2.id and bug19634()";
execute stmt;
execute stmt;
deallocate prepare stmt;
create trigger t1_bi before delete on t1 for each row insert into t3 values (old.data);
prepare stmt from "delete t1 from t1, t2 where t1.id = t2.id";
execute stmt;
execute stmt;
deallocate prepare stmt;
drop function bug19634;
drop table t1, t2, t3;
End of 5.0 tests
......@@ -272,3 +272,34 @@ drop table t1;
drop view v1, v2, v3;
drop function bug15683;
#
# Bug#19634 "Re-execution of multi-delete which involve trigger/stored
# function crashes server"
#
--disable_warnings
drop table if exists t1, t2, t3;
drop function if exists bug19634;
--enable_warnings
create table t1 (id int, data int);
create table t2 (id int);
create table t3 (data int);
create function bug19634() returns int return (select count(*) from t3);
prepare stmt from "delete t1 from t1, t2 where t1.id = t2.id and bug19634()";
# This should not crash server
execute stmt;
execute stmt;
deallocate prepare stmt;
create trigger t1_bi before delete on t1 for each row insert into t3 values (old.data);
prepare stmt from "delete t1 from t1, t2 where t1.id = t2.id";
execute stmt;
execute stmt;
deallocate prepare stmt;
drop function bug19634;
drop table t1, t2, t3;
--echo End of 5.0 tests
......@@ -5202,8 +5202,26 @@ bool check_global_access(THD *thd, ulong want_access)
/*
Check the privilege for all used tables. Table privileges are cached
in the table list for GRANT checking
Check the privilege for all used tables.
SYNOPSYS
check_table_access()
thd Thread context
want_access Privileges requested
tables List of tables to be checked
no_errors FALSE/TRUE - report/don't report error to
the client (using my_error() call).
NOTES
Table privileges are cached in the table list for GRANT checking.
This functions assumes that table list used and
thd->lex->query_tables_own_last value correspond to each other
(the latter should be either 0 or point to next_global member
of one of elements of this table list).
RETURN VALUE
FALSE - OK
TRUE - Access denied
*/
bool
......@@ -7068,14 +7086,28 @@ bool multi_delete_precheck(THD *thd, TABLE_LIST *tables)
SELECT_LEX *select_lex= &thd->lex->select_lex;
TABLE_LIST *aux_tables=
(TABLE_LIST *)thd->lex->auxilliary_table_list.first;
TABLE_LIST **save_query_tables_own_last= thd->lex->query_tables_own_last;
DBUG_ENTER("multi_delete_precheck");
/* sql_yacc guarantees that tables and aux_tables are not zero */
DBUG_ASSERT(aux_tables != 0);
if (check_db_used(thd, tables) || check_db_used(thd,aux_tables) ||
check_table_access(thd,SELECT_ACL, tables,0) ||
check_table_access(thd,DELETE_ACL, aux_tables,0))
check_table_access(thd, SELECT_ACL, tables, 0))
DBUG_RETURN(TRUE);
/*
Since aux_tables list is not part of LEX::query_tables list we
have to juggle with LEX::query_tables_own_last value to be able
call check_table_access() safely.
*/
thd->lex->query_tables_own_last= 0;
if (check_table_access(thd, DELETE_ACL, aux_tables, 0))
{
thd->lex->query_tables_own_last= save_query_tables_own_last;
DBUG_RETURN(TRUE);
}
thd->lex->query_tables_own_last= save_query_tables_own_last;
if ((thd->options & OPTION_SAFE_UPDATES) && !select_lex->where)
{
my_message(ER_UPDATE_WITHOUT_KEY_IN_SAFE_MODE,
......
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