#49585 [Opn]: date_format buffer not long enough for >4 digit years

ID: 49585 Updated by: aharvey@php.net Reported By: aharvey@php.net Status: Open Bug Type: Date/time related Operating System: Linux (Ubuntu 9.04) PHP Version: 5.3SVN-2009-09-18 (SVN) New Comment: Gah, just found another corner case while writing the PHPT case. The "short" day name used by 'r' may not actually be three characters in all cases -- 'Unknown' can be returned. Ergo, we need another four characters. Revised patch: http://www.adamharvey.name/stuff/date-format-buffer-64-revised.patch PHPT test case: http://www.adamharvey.name/stuff/bug49585.phpt Previous Comments: ------------------------------------------------------------------------ [2009-09-18 09:10:18] aharvey@php.net By which I mean http://www.adamharvey.name/stuff/date-format-buffer-64.patch -- the PHP bug tracker's autolinking picked up the full stop. :) ------------------------------------------------------------------------ [2009-09-18 09:09:32] aharvey@php.net Actually, I'm running a 64 bit machine anyway; the point is that the explicit (int) cast will be 32 bit regardless on an LP64 or LLP64 architecture. Nevertheless, a patch that can definitely handle 64 bit ints is at http://www.adamharvey.name/stuff/date-format-buffer-64.patch. ------------------------------------------------------------------------ [2009-09-18 09:01:48] derick@php.net Oh, and a few phpt test cases would be awesome too :-) ------------------------------------------------------------------------ [2009-09-18 09:00:53] derick@php.net Actually, 64bit machines are getting pretty much common, so could you please update your patch? ------------------------------------------------------------------------ [2009-09-18 08:49:10] aharvey@php.net Description: ------------ The buffer allocated within date_format() isn't long enough for RFC 2822 formatted dates (format string 'r') when the year requires five or more characters to be represented, which causes the output to be truncated. ISO 8601 dates ('c') are also affected, but only in the absolute extreme case, as demonstrated below. The naïve approach is obviously to extend the buffer size, and the patch (against the current PHP_5_3 checkout) at http://www.adamharvey.name/stuff/date-format-buffer.patch extends it far enough to cover all possible contingencies on common platforms -- since date_format() casts the year to a signed int when it calls slprintf(), the longest possible value that needs to be catered for in the year field is -2147483648 on any platform where int is 32 bit, which is pretty much all of them. Reproduce code: --------------- <?php $date = new DateTime('-1500-01-01'); var_dump($date->format('r')); $date->setDate(pow(2, 31), 1, 1); var_dump($date->format('r')); var_dump($date->format('c')); ?> Expected result: ---------------- string(32) "Sat, 01 Jan -1500 00:00:00 +0800" string(38) "Wed, 01 Jan -2147483648 00:00:00 +0800" string(32) "-2147483648-01-01T00:00:00+08:00" Actual result: -------------- string(31) "Sat, 01 Jan -1500 00:00:00 +080" string(31) "Wed, 01 Jan -2147483648 00:00:0" string(31) "-2147483648-01-01T00:00:00+08:0" ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=49585&edit=1