Bug #63208 [Opn->Ana]: Wrong conversion of byte array VARIANT which contains null byte to string
| From: | cmb@php.net | Date: | Sun, 16 Aug 2015 16:25:45 +0000 |
| Subject: | Bug #63208 [Opn->Ana]: Wrong conversion of byte array VARIANT which contains null byte to string | ||
| References: | 1 | Groups: | php.bugs |
| Request: | Send a blank email to php-bugs+get-195247@lists.php.net to get a copy of this message | ||
Edit report at https://bugs.php.net/bug.php?id=63208&edit=1
ID: 63208
Updated by: cmb@php.net
Reported by: gopeyx at gmail dot com
Summary: Wrong conversion of byte array VARIANT which
contains null byte to string
-Status: Open
+Status: Analyzed
Type: Bug
Package: COM related
Operating System: Windows NT W-AM-13079 6.1 build
PHP Version: 5.3.17
Block user comment: N
Private report: N
New Comment:
The problem is that php_com_olestring_to_string()[1] is not binary
safe, because it passes -1 to the cchWideChar parameter of
WideCharToMultiByte()[2]. That causes WideCharToMultiByte() to
stop at the first null character (actually, two null bytes), and
so the rest of the string is ignored.
As a BSTR[3] has a prefix containing its length in bytes it
appears we could use this to calculate the proper cchWideChar
argument, see the attached patch.
[1] <https://github.com/php/php-src/blob/php-7.0.0beta3/ext/com_dotnet/com_olechar.c#L74>
[2] <https://msdn.microsoft.com/en-us/library/windows/desktop/dd374130(v=vs.85).aspx>
[3] <https://msdn.microsoft.com/en-us/library/windows/desktop/ms221069(v=vs.85).aspx>
Previous Comments:
------------------------------------------------------------------------
[2012-10-11 15:38:01] tomas dot var at dtr-sistemas dot com
I have the same problem when I want to extract the value of a LONGBINARY field from an MS-Access or
MSSQL Database (OLE Field exactly), and the OLE embeeded header contains some zero bytes. I can
obtain only 3 bytes when it converts to a string for save to a file. And when I loop with
"foreach" the VARIANT ARRAY of UNSIGNED BYTES it loops correctly (except for the byte
'\0' after every valid byte) and if I count the array with
"count($field->Value)" for example, it results the double lenght that expects.
Why don't exists in PHP a way to obtain a simple array of bytes for a variable, or access the
data like a "string" of bytes?
------------------------------------------------------------------------
[2012-10-03 12:40:18] gopeyx at gmail dot com
Description:
------------
I have a VARIANT of type 8209 which is an array of bytes (VT_ARRAY | VT_UI1).
This array contains null byte in the middle.
When trying to convert it to a string only bytes before null byte are used. Others are ignored.
But they are present in the object. You can see it if you walk through the bytes of variant via
foreach().
Test script:
---------------
<?php
$string = "ab\0cd";
$variant = new VARIANT($string, VT_ARRAY | VT_UI1); // Array of bytes
$converted = (string) $variant;
var_dump($string);
var_dump($converted);
Expected result:
----------------
string(5) "abcd"
string(5) "abcd"
// $converted variable should be equal to the original $string and should contain 5 characters.
Actual result:
--------------
string(5) "abcd"
string(2) "ab"
------------------------------------------------------------------------
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Edit this bug report at https://bugs.php.net/bug.php?id=63208&edit=1