Edit report at https://bugs.php.net/bug.php?id=55475&edit=1

 ID:                 55475
 Comment by:         martijn dot niji at gmail dot com
 Reported by:        mads at gartneriet dot dk
 Summary:            is_a() triggers autoloader
 Status:             Closed
 Type:               Bug
 Package:            Scripting Engine problem
 PHP Version:        5.3.7
 Assigned To:        dmitry
 Block user comment: N
 Private report:     N
 CVE-ID:             2011-3379

 New Comment:

I must agree with the people who say that is_a('stdClass', 'stdClass') should 
not return true.

The is_a() function is intended as a function that checks a certain condition 
is true, that condition being that a certain variable/object is of a certain 
type/class.

Having is_a() try to automatically load a class by calling autoload is bad 
behaviour at best and a code breaking security flaw at worst.


Previous Comments:
------------------------------------------------------------------------
[2012-07-24 23:39:01] [email protected]

Automatic comment on behalf of stas
Revision: 
http://git.php.net/?p=php-src.git;a=commit;h=10f20585fcbd524016e439c17bf01a0fd5191107
Log: fix bug #55475 - implement is_a BC solution

------------------------------------------------------------------------
[2012-07-02 10:30:29] rmc1134 at gmail dot com

I don't get it: why should is_a() accept a string as its first argument?

This function is supposed to be a check on AN OBJECT and is_a('stdClass', 
'stdClass') SHOULD NOT EVER RETURN any truthy value.

Calling __autoload() to check whether some string might be some object is 
something a programmer should do, not the language.

------------------------------------------------------------------------
[2012-04-18 09:47:55] [email protected]

Automatic comment on behalf of stas
Revision: 
http://git.php.net/?p=php-src.git;a=commit;h=10f20585fcbd524016e439c17bf01a0fd5191107
Log: fix bug #55475 - implement is_a BC solution

------------------------------------------------------------------------
[2012-01-09 08:27:48] counterpoint at aliro dot org

It's worrying that something that appears to have been accidentally introduced 
is then justified as how things should work.  Little attention seems to be paid 
to how people may have been using the mechanism that has changed.  The whole 
thrust in this area was for is_a to test something that is supposed to be an 
instance.  Indeed, the at one time intended replacement for is_a is called 
"instanceof" and a string is not an instance of anything.  Changing an 
operation called "instanceof" to accept a class name ahead of the operator 
would seem perverse in the extreme.  Clearly the altered behavior of is_a may 
break any autoloader that assumes that it will only ever receive strings that 
can be assumed to be class names.  In particular, consider the common case 
where a set of class names can be mapped to a set of file names: in this 
situation, it is not unreasonable for the autoloader to terminate immediately 
if it receives a class name that contains ".." because this is very likely a 
hack attempt.

------------------------------------------------------------------------
[2011-11-09 05:27:49] [email protected]

This bug has been fixed in SVN.

Snapshots of the sources are packaged every three hours; this change
will be in the next snapshot. You can grab the snapshot at
http://snaps.php.net/.

 For Windows:

http://windows.php.net/snapshots/
 
Thank you for the report, and for helping us make PHP better.



------------------------------------------------------------------------


The remainder of the comments for this report are too long. To view
the rest of the comments, please view the bug report online at

    https://bugs.php.net/bug.php?id=55475


-- 
Edit this bug report at https://bugs.php.net/bug.php?id=55475&edit=1

Reply via email to