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Bug#38469 invalid memory read and/or crash with utf8 text field, stored procedure, uservar

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A stored procedure involving substrings could crash the server on certain
platforms because of invalid memory reads.
          
During storing the new blob-field value, the cached value's address range
overlapped that of the new field value. This caused problems when the 
cached value storage was reallocated to provide access for a new 
characater set representation. The patch checks the address ranges, and if
they overlap, the new field value is copied to a new storage before it is
converted to the new character set.


mysql-test/r/sp.result:
  Added result set
mysql-test/t/sp.test:
  Added test case
sql/field.cc:
  The source and destination address ranges of a character conversion must not overlap or the 'from' address will be invalidated as the temporary value-
  object is re-allocated to fit the new character set.
sql/field.h:
  Added comments
This commit is contained in:
Kristofer Pettersson
2008-09-20 10:51:03 +02:00
parent bed8cec485
commit f0352e346a
4 changed files with 48 additions and 2 deletions
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10
mysql-test/r/sp.result
View File

@ -6662,6 +6662,16 @@ drop procedure p1;
drop function f1;
drop view v1;
drop table t1;
drop procedure if exists `p2` $
create procedure `p2`(in `a` text charset utf8)
begin
declare `pos` int default 1;
declare `str` text charset utf8;
set `str` := `a`;
select substr(`str`, `pos`+ 1 ) into `str`;
end $
call `p2`('s s s s s s');
drop procedure `p2`;
# ------------------------------------------------------------------
# -- End of 5.0 tests
# ------------------------------------------------------------------

18
mysql-test/t/sp.test
View File

@ -7818,6 +7818,24 @@ drop function f1;
drop view v1;
drop table t1;
#
# Bug#38469 invalid memory read and/or crash with utf8 text field, stored procedure, uservar
#
delimiter $;
--disable_warnings
drop procedure if exists `p2` $
--enable_warnings
create procedure `p2`(in `a` text charset utf8)
begin
declare `pos` int default 1;
declare `str` text charset utf8;
set `str` := `a`;
select substr(`str`, `pos`+ 1 ) into `str`;
end $
delimiter ;$
call `p2`('s s s s s s');
drop procedure `p2`;
--echo # ------------------------------------------------------------------
--echo # -- End of 5.0 tests
--echo # ------------------------------------------------------------------

12
sql/field.cc
View File

@ -6992,8 +6992,18 @@ int Field_blob::store(const char *from,uint length,CHARSET_INFO *cs)
return 0;
}
if (from == value.ptr())
/*
If the 'from' address is in the range of the temporary 'value'-
object we need to copy the content to a different location or it will be
invalidated when the 'value'-object is reallocated to make room for
the new character set.
*/
if (from >= value.ptr() && from <= value.ptr()+value.length())
{
/*
If content of the 'from'-address is cached in the 'value'-object
it is possible that the content needs a character conversion.
*/
uint32 dummy_offset;
if (!String::needs_conversion(length, cs, field_charset, &dummy_offset))
{

10
sql/field.h
View File

@ -1213,8 +1213,16 @@ public:
class Field_blob :public Field_longstr {
protected:
/**
The number of bytes used to represent the length of the blob.
*/
uint packlength;
String value; // For temporaries
/**
The 'value'-object is a cache fronting the storage engine.
*/
String value;
public:
Field_blob(char *ptr_arg, uchar *null_ptr_arg, uchar null_bit_arg,
enum utype unireg_check_arg, const char *field_name_arg,