From 71ee8615c34db5299d51bc440309371ea08b5923 Mon Sep 17 00:00:00 2001
From: unknown <evgen@moonbone.local>
Date: Tue, 21 Feb 2006 18:09:32 +0300
Subject: [PATCH] Fixed bug#17530: Incorrect key truncation on table creation
 caused server crash.

When a too long field is used for a key, only a prefix part of the field is
used. Length is reduced to the max key length allowed for storage. But if the
field have a multibyte charset it is possible to break multibyte char
sequence. This leads to the failed assertion in the innodb code and
server crash when a record is inserted.

The make_prepare_table() now aligns truncated key length to the boundary of
multibyte char.


mysql-test/t/create.test:
  Added test case for bug#17530: Incorrect key truncation on table creation caused server crash.
mysql-test/r/create.result:
  Added test case for bug#17530: Incorrect key truncation on table creation caused server crash.
sql/sql_table.cc:
  Fixed bug#17530: Incorrect key truncation on table creation caused server crash.
  The make_prepare_table() now aligns truncated key length to the boundary of
  multibyte char.
---
 mysql-test/r/create.result | 6 ++++++
 mysql-test/t/create.test   | 8 ++++++++
 sql/sql_table.cc           | 4 +++-
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/mysql-test/r/create.result b/mysql-test/r/create.result
index 848b84e2b8c..8c1943486b5 100644
--- a/mysql-test/r/create.result
+++ b/mysql-test/r/create.result
@@ -765,3 +765,9 @@ t1	CREATE TABLE `t1` (
   `i` int(11) default NULL
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1 MAX_ROWS=4294967295
 drop table t1;
+create table t1(f1 varchar(800) binary not null, key(f1)) engine = innodb 
+character set utf8 collate utf8_general_ci;
+Warnings:
+Warning	1071	Specified key was too long; max key length is 765 bytes
+insert into t1 values('aaa');
+drop table t1;
diff --git a/mysql-test/t/create.test b/mysql-test/t/create.test
index f7b9002faa0..9fcbb53e24d 100644
--- a/mysql-test/t/create.test
+++ b/mysql-test/t/create.test
@@ -660,4 +660,12 @@ alter table t1 max_rows=100000000000;
 show create table t1;
 drop table t1;
 
+#
+# Bug#17530: Incorrect key truncation on table creation caused server crash.
+#
+create table t1(f1 varchar(800) binary not null, key(f1)) engine = innodb 
+  character set utf8 collate utf8_general_ci;
+insert into t1 values('aaa');
+drop table t1;
+
 # End of 5.0 tests
diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index de350b83985..a84d70f7835 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -1299,7 +1299,9 @@ static int mysql_prepare_table(THD *thd, HA_CREATE_INFO *create_info,
       }
       if (length > file->max_key_part_length() && key->type != Key::FULLTEXT)
       {
-	length=file->max_key_part_length();
+        length= file->max_key_part_length();
+        /* Align key length to multibyte char boundary */
+        length-= length % sql_field->charset->mbmaxlen;
 	if (key->type == Key::MULTIPLE)
 	{
 	  /* not a critical problem */