Bug #53608 [Ver]: mktime() produces invalid results under 64-bit

From: Date: Thu, 31 Mar 2011 10:05:49 +0000
Subject: Bug #53608 [Ver]: mktime() produces invalid results under 64-bit
References: 1  Groups: php.bugs 
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Edit report at http://bugs.php.net/bug.php?id=53608&edit=1

 ID:                 53608
 Updated by:         cataphract@php.net
 Reported by:        jer_826 at yahoo dot com
 Summary:            mktime() produces invalid results under 64-bit
 Status:             Verified
 Type:               Bug
 Package:            Date/time related
 Operating System:   Linux 2.6.35.7  x86_64
 PHP Version:        5.2.16
 Block user comment: N
 Private report:     N

 New Comment:

I think the only reasonable fix here is to check the range of the
arguments on the beginning of the function. Checking for overflow
everywhere doesn't seem very handy since there are lots of places and
functions (which would have to be changed to signal overflow errors)
where this would have to be done.


Previous Comments:
------------------------------------------------------------------------
[2011-01-04 07:39:58] aharvey@php.net

Confirmed; the error handling in timelib_date_to_int() is insufficient
for platforms with 64 bit longs.

The quick and dirty fix would be to explicitly compare ts in
timelib_date_to_int() to the minimum and maximum values of a 32 bit
integer, but you'd then lose the ability to use mktime() for dates
outside the 1901-2038 range. Better would be to try to detect overflow
in timelib_update_ts(), but that's not going to be foolproof either.

I don't have any particularly strong feelings on this one, or even
whether it's worth trying to handle. Derick?

------------------------------------------------------------------------
[2011-01-02 09:52:16] brad at njoe dot com

Confirmed on Ubuntu 10.10 (Linux 2.6.35-24-server x86_64). Also tested a
Win32 
build and all three var_dumps() show "bool(false)" as
expected/documented.

------------------------------------------------------------------------
[2010-12-24 22:19:04] jer_826 at yahoo dot com

Description:
------------
It appears that when the PHP binary was compiled against 64-bit
libraries,  
mktime() seems to only do minimal error checking of parms. After some
additional 
testing, if found the following results:
PHP Code:
$t=mktime(0,0,0,12,3,292277026596); 
var_dump($t); 

$t=mktime(0,0,0,12,3,292277026597); 
var_dump($t); 

$t=mktime(900000000000,900000000000,900000000000,900000000000,900000000000,90000
0000000); 

var_dump($t); 
int(9223372036854655200)
int(-9223372036823360416) 
int(-6044405109589065632)

It appears that once the parm value exceeds the value limit of a long
var, the 
function returns a negative value. No warnings are produced. Instead of

returning FALSE for an error, the function just returns an invalid
result.

Some additional info here: http://phpbuilder.com/board/showthread.php?
p=10971046#post10971046

Test script:
---------------
$t=mktime(0,0,0,12,3,292277026596); 
var_dump($t); 

$t=mktime(0,0,0,12,3,292277026597); 
var_dump($t); 

$t=mktime(900000000000,900000000000,900000000000,900000000000,900000000000,900000000000);


var_dump($t); 
int(9223372036854655200)
int(-9223372036823360416) 
int(-6044405109589065632)

Expected result:
----------------
Return FALSE if parms are invalid.

Actual result:
--------------
Invalid values. Does not return FALSE.


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



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