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Bug#18539 uncompress(d) is null: impossible?

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- Add a check that length of field to uncompress is longer than 4 bytes.
   This can be dones as the length of uncompressed data is written as 
   first four bytes of field and thus it can't be valid compressed data.


mysql-test/r/func_compress.result:
  Update test results
sql/item_strfunc.cc:
  Is size of field is less than or equal to 4 bytes, indicate data is uncompressable/corrupt.
This commit is contained in:
unknown
2006-07-18 12:41:41 +02:00
parent b46c81e109
commit 7f2140d3ed
2 changed files with 15 additions and 5 deletions
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10
mysql-test/r/func_compress.result
View File

@ -85,12 +85,12 @@ explain select * from t1 where uncompress(a) is null;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 system NULL NULL NULL NULL 1
Warnings:
Error 1256 Uncompressed data size too large; the maximum size is 104857600 (probably, length of uncompressed data was corrupted)
Error 1259 ZLIB: Input data corrupted
select * from t1 where uncompress(a) is null;
a
foo
Warnings:
Error 1256 Uncompressed data size too large; the maximum size is 104857600 (probably, length of uncompressed data was corrupted)
Error 1259 ZLIB: Input data corrupted
explain select *, uncompress(a) from t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 system NULL NULL NULL NULL 1
@ -98,12 +98,12 @@ select *, uncompress(a) from t1;
a uncompress(a)
foo NULL
Warnings:
Error 1256 Uncompressed data size too large; the maximum size is 104857600 (probably, length of uncompressed data was corrupted)
Error 1259 ZLIB: Input data corrupted
select *, uncompress(a), uncompress(a) is null from t1;
a uncompress(a) uncompress(a) is null
foo NULL 1
Warnings:
Error 1256 Uncompressed data size too large; the maximum size is 104857600 (probably, length of uncompressed data was corrupted)
Error 1256 Uncompressed data size too large; the maximum size is 104857600 (probably, length of uncompressed data was corrupted)
Error 1259 ZLIB: Input data corrupted
Error 1259 ZLIB: Input data corrupted
drop table t1;
End of 5.0 tests

10
sql/item_strfunc.cc
View File

@ -2965,6 +2965,16 @@ String *Item_func_uncompress::val_str(String *str)
if (res->is_empty())
return res;
/* If length is less than 4 bytes, data is corrupt */
if (res->length() <= 4)
{
push_warning_printf(current_thd,MYSQL_ERROR::WARN_LEVEL_ERROR,
ER_ZLIB_Z_DATA_ERROR,
ER(ER_ZLIB_Z_DATA_ERROR));
goto err;
}
/* Size of uncompressed data is stored as first 4 bytes of field */
new_size= uint4korr(res->ptr()) & 0x3FFFFFFF;
if (new_size > current_thd->variables.max_allowed_packet)
{