Req #63510 [Asn]: Integer overflow with chr should be able to be detected

Edit report at https://bugs.php.net/bug.php?id=63510&edit=1 ID: 63510 Updated by: yohgaki@php.net Reported by: idokan at gmail dot com -Summary: Integer overflow with chr +Summary: Integer overflow with chr should be able to be detected Status: Assigned Type: Feature/Change Request Package: Strings related PHP Version: 5.4.8 Assigned To: yohgaki Block user comment: N Private report: N New Comment: Should we close this bug? I'm fine with documentation change. chr() may have strict option that detects overflow, also. string chr(long $code [, bool $strict=FALSE]) Previous Comments: ------------------------------------------------------------------------ [2016-07-01 20:07:19] cmb@php.net Automatic comment from SVN on behalf of cmb Revision: http://svn.php.net/viewvc/?view=revision&amp;revision=339537 Log: Address #63510: Integer overflow with chr ------------------------------------------------------------------------ [2016-07-01 19:49:28] cmb@php.net It seems to be appropriate to point out why this ticket had been changed to feature request. :) > Not to $value & 255 it. Actually, the integer is simply cast to char and used as the first and only byte of the returned string[1]. Of course, this behavior is questionable, but changing it would cause a BC break, so it can't be done in a minor version or even a patch release without a very good reason. Simply stating "you must report an error like XYZ" is not a very good reason, in my opinion. I'd rather fix the docs and maybe change the behavior in the next major version. [1] <https://github.com/php/php-src/blob/php-7.0.8/ext/standard/string.c#L2793> ------------------------------------------------------------------------ [2012-11-14 15:36:32] idokan at gmail dot com Huh ?! ASCII is 0..127 chars, if they are out of range and also from extended ASCII (128..255), then you must report an error like with normal implementation such as Ruby, Python, Pascal, Perl (with strict bytes) etc... Not to $value & 255 it. ------------------------------------------------------------------------ [2012-11-14 15:28:28] laruence@php.net I think this check could be done in user script self. the document said: chr convert *ascii* code .. so... ------------------------------------------------------------------------ [2012-11-14 09:36:12] idokan at gmail dot com Description: ------------ The chr function translate a single Byte length integer into it's ASCII value. When providing a number bigger then 255, it returns the first byte instead of reporting an error about being out of range. Test script: --------------- echo chr(1000) . ' ' . ord(chr(1000)) . "\n"; Expected result: ---------------- chr must check the numeric boundaries and report on on an error when they are out of the range. Actual result: -------------- returns the first byte out of the result, making it appear like an integer overflow that the carry flag exception was captured. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=63510&edit=1