Edit report at https://bugs.php.net/bug.php?id=62983&edit=1
ID: 62983
Updated by: php-bugs@lists.php.net
Reported by: bkfake-php at yahoo dot com
Summary: if user exceeds post_max_size, script may hang on
output
-Status: Feedback
+Status: No Feedback
Type: Bug
Package: Output Control
Operating System: Windows
PHP Version: 5.4.6
New Comment:
No feedback was provided. The bug is being suspended because
we assume that you are no longer experiencing the problem.
If this is not the case and you are able to provide the
information that was requested earlier, please do so and
change the status of the bug back to "Open". Thank you.
Previous Comments:
------------------------------------------------------------------------
[2013-02-02 23:37:59] jan at lanteraudio dot nl
Using Apache 2.2 PHP 5.3.5 win xp pro sp3 FF16
Same problem
Very simple script, as soon as uploaded file size exceeds post_max_size script
stops executing, no error message, so no way to inform users they input a too
big file.
------------------------------------------------------------------------
[2012-08-31 18:00:48] bkfake-php at yahoo dot com
Apache 2.2
My apologies if I incorrectly categorized this finding under "Output Control"
------------------------------------------------------------------------
[2012-08-31 16:27:02] larue...@php.net
are you using builtin webserver?
------------------------------------------------------------------------
[2012-08-31 15:13:14] bkfake-php at yahoo dot com
Description:
------------
set post_max_size in php.ini to something relatively small (for easy testing)
say 2M or 3M
upload_max_filesize setting does not matter...
though for practical reasons it should be smaller than post_max_size
if posted data exceeds post_max_size... output seems to be limited to under
24500 - 33000 bytes (a modest amount of html) as soon as that unknown
amount is exceeded, the script "hangs"?
* next statement after the triggering echo (or print or file passthru, etc) is
not executed.
* headers not received by browser,
* max_execution_time not reached
* no errors generated (other than Warning "POST Content-Length of xxxx bytes
exceeds the limit of xxxx bytes in Unknown on line 0,")
firefox just sits spinning "Sending request to localhost..."
IE says waiting for....
Test script:
---------------
<?php
/**
* set post_max_size in php.ini to something relatively small (for easy
testing)
* say 2M or 3M
* upload_max_filesize setting does not matter...
* though for practical reasons it should be smaller than post_max_size
*
* now using this script, upload a file that's over that limit.
*/
if ( $_SERVER['REQUEST_METHOD'] == 'POST' )
{
/**
* change $output_length to trigger the bug
* on one system I tested, the magic number is 24506.. crashes at
24507
* on another the number is 32742.. crashes at 32743
* what limit am I encountering?
* this number appears to be arbitrary... varying by system and
* I think the scripts memory usage also affects how much may be
returned
* the number seems to remain static to that system..
* but if I change this script, the number may change
* (ie, changing the length of $repeat_str below)
*/
$output_length = 24593; // increase/decrease to
trigger/not-trigger the bug
//
$repeat_str = 'Too much arbitrary output and this script will hang.
Why so?'."\n";
// even changing the length of $repeat_str seems to affect the total
amount that can be output
// perhaps due to change in memory usage?
header('Content-Length: '.$output_length); // adding/removing
headers does not have any effect
$strlen_repeat_str = strlen($repeat_str);
// output $repeat_str until out $strlen_output = $output_length
$strlen_output = 0; // including closing div;
while ( $strlen_output < $output_length )
{
$diff = $output_length - $strlen_output;
if ( $diff >= $strlen_repeat_str )
{
$strlen_output += $strlen_repeat_str;
echo $repeat_str;
}
else
{
$strlen_output += $diff;
echo substr($repeat_str,0,$diff);
}
}
// when we go over $output_length, script seems to hang on echo
statement...
// headers not received by browser,
// max_execution_time not reached
// no errors generated (other than "PHP Warning localhost
POST Content-Length of xxxx bytes exceeds the limit of xxxx bytes in Unknown on
line 0,")
// firefox just sits spinning "Sending request to localhost..."
// IE says waiting for....
}
else
{
echo 'uploading a file with a size over '.ini_get('post_max_size').' =
potential crash';
?>
<form enctype="multipart/form-data" action="" method="post" >
<input type="file" name="file" />
<input type="submit" value="submit me!" />
</form>
<?php
}
?>
Expected result:
----------------
initial file-upload form...
after submitting the response should be the string
"Too much arbitrary output and this script will hang. Why so?" repeated
400+times
Actual result:
--------------
script hangs -> nothing returned
------------------------------------------------------------------------
--
Edit this bug report at https://bugs.php.net/bug.php?id=62983&edit=1
