Bug #7659

strlen() wrongly used to count number of bytes in data buffer

Details

Submitted	2006-05-18 08:55 UTC
From	dsier at g-point dot biz
Status	Bogus
Package	HTTP_Download
PHP Version	Irrelevant
Roadmaps	(Not assigned)

Comments

[2006-05-18 08:55 UTC] dsier at g-point dot biz

Description:
------------
There are a few places where strlen() is used to count number of bytes in data buffer (Download::setData(), Download::flush()). This is wrong - strlen is not supposed to return number of bytes but number of characters in string.

Of course under normal circumstances those are equal, unless someone uses mb_internal_encoding() and sets internal encoding to some multibyte encoding (like UTF-8).

This may cause incorrect length to be reported by Content-Length and corrupted downloads.

Test script:
---------------
Possible workaround - use bytelen functions defined as:

function bytelen($data)
{
if (function_exists('mb_strlen')) {
return mb_strlen($data, 'latin1');
}

return strlen($data);
}

Note: "mb_internal_encoding" affects also other string-related functions (substr for example). So it can also affect other HTTP_Download methods like sendChunk() etc.

[2007-01-13 18:46 UTC] dsier at g-point dot biz

Bogus?

I don't think so. Here's example of code that gives wrong results (downloaded file is truncated). Tested with HTTP_Download 1.1.1.

http://www.g-point.biz/~dsier/bug.zip

Make sure that mbstring.func_overload is set to '2' in php.ini before you try it.