From 39509d64c370b5a309f1c905d847ea0f92921327 Mon Sep 17 00:00:00 2001
From: unknown <kostja@dipika.(none)>
Date: Wed, 30 Jan 2008 18:27:41 +0300
Subject: 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().
---
 sql/sql_plugin.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'sql/sql_plugin.cc')

diff --git a/sql/sql_plugin.cc b/sql/sql_plugin.cc
index 2a86844c8c6..5cd056807a6 100644
--- a/sql/sql_plugin.cc
+++ b/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 */
-- 
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