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BUG#24437124: POSSIBLE BUFFER OVERFLOW ON CREATE TABLE

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ANALYSIS:
=========
'CREATE TABLE' query with a large value for 'CONNECTION'
string reports an incorrect error.

The length of connection string is stored in .frm in two
bytes (max value= 65535). When the string length exceeds
the max value, the length is truncated to fit the two
bytes limit. Further processing leads to reading only a
part of the string as the length stored is incorrect. The
remaining part of the string is treated as engine type and
hence results in an error.

FIX:
====
We are now restricting the connection string length to 1024.
An appropriate error is reported if the length crosses this
limit.

NOTE:
=====
The 'PASSWORD' table option is documented as unused and
processed within a dead code. Hence it will not cause
similar issue with large strings.
This commit is contained in:
Karthik Kamath 2016-11-10 15:11:57 +05:30
parent 2f2103d540
commit a63185e863
2 changed files with 17 additions and 1 deletions
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3
include/mysql_com.h
View File

@ -1,4 +1,4 @@
/* Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
/* Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
@ -26,6 +26,7 @@
#define USERNAME_CHAR_LENGTH 16
#define NAME_LEN (NAME_CHAR_LEN*SYSTEM_CHARSET_MBMAXLEN)
#define USERNAME_LENGTH (USERNAME_CHAR_LENGTH*SYSTEM_CHARSET_MBMAXLEN)
#define CONNECT_STRING_MAXLEN 1024
#define MYSQL_AUTODETECT_CHARSET_NAME "auto"

15
sql/sql_table.cc
View File

@ -2851,6 +2851,21 @@ mysql_prepare_create_table(THD *thd, HA_CREATE_INFO *create_info,
uint total_uneven_bit_length= 0;
DBUG_ENTER("mysql_prepare_create_table");
LEX_STRING* connect_string = &create_info->connect_string;
if (connect_string->length != 0 &&
connect_string->length > CONNECT_STRING_MAXLEN &&
(system_charset_info->cset->charpos(system_charset_info,
connect_string->str,
(connect_string->str +
connect_string->length),
CONNECT_STRING_MAXLEN)
< connect_string->length))
{
my_error(ER_WRONG_STRING_LENGTH, MYF(0),
connect_string->str, "CONNECTION", CONNECT_STRING_MAXLEN);
DBUG_RETURN(TRUE);
}
select_field_pos= alter_info->create_list.elements - select_field_count;
null_fields=blob_columns=0;
create_info->varchar= 0;