Bug #67363 [Opn]: Unserialize corrupts data

Edit report at https://bugs.php.net/bug.php?id=67363&edit=1 ID: 67363 User updated by: mg at artigo dot pl Reported by: mg at artigo dot pl Summary: Unserialize corrupts data Status: Open Type: Bug Package: Variables related Operating System: Irrelavant PHP Version: Irrelevant Block user comment: N Private report: N New Comment: Regarding the original problem with unserialize corruption issue: In this single case "Make-up & Styling" became "Make-up ' Sty ing" & = hex 26 became ' = hex 27 l = hex 6c became (nul) = hex 00 The changes in characters are always different and seem random. It is worth mentioning that the issue appears out of nowhere and can be fixed by restarting the server. It seems memory related. For this reason it is not possible to provide a bug testing snippet, because it simply won't create the same issue on another machine, although it may get it's own unique corruption on a random day. The issue presents itself always on Apache server (various versions 2-2.4), mod_php or FCGI. Previous Comments: ------------------------------------------------------------------------ [2014-06-02 06:52:16] mg at artigo dot pl The information in comments is irrelevant. The corruption does not occur, because the object itself changes, but it is the same with any change of it - only some combinations of values cause corruption. The difference in serialize output is related to classes serialize method which removes the "parent" field. ------------------------------------------------------------------------ [2014-05-30 17:18:50] mg at artigo dot pl It turns out I simplified Case 1 too much, I attach the whole information again: ------------ It seems that serialize function has something to do with it. It returns different outputs in the following cases: Case 1: unserialize(serialize($data)); echo serialize($data); // output: https://dl.dropboxusercontent.com/u/11435743/php/serialize_unserialize_serialize.txt Case 2: echo serialize($data); // output: https://dl.dropboxusercontent.com/u/11435743/php/serialize.txt Data corruption DOES NOT occur when I run unserialize on the output of Case 1. Data corruption DOES occur when I run unserialize on the output of Case 2. Example of the currupted outputs are attached in the original post. To summarize: putting additional unserialize(serialize($data)); before serialize($data); seems to workaround the corruption by resulting in a different output of the second call of serialize function. This output can then be safely passed to unserialize function and the corruption does not occur. ------------------------------------------------------------------------ [2014-05-30 17:00:41] mg at artigo dot pl Please excuse the error in the sentence: I attach this example, because data corruption does NOT seem to occur in Case 1. It seems only to occur in Case 2. ------------------------------------------------------------------------ [2014-05-30 16:55:42] mg at artigo dot pl It seems that serialize function has something to do with it, it gives different outputs: Case1, output of: serialize(unserialize(serialize($data))); https://dl.dropboxusercontent.com/u/11435743/php/serialize_unserialize_serialize.txt Case 2, output of: serialize($data) https://dl.dropboxusercontent.com/u/11435743/php/serialize.txt I attach this example, because data corruption does seem to occur in Case 1. It seems only to occur in Case 2. ------------------------------------------------------------------------ [2014-05-30 15:26:26] mg at artigo dot pl Description: ------------ Unserialize method of PHP corrupts random values inside serialized objects. Corrupted value may be a string (in this case it is clearly visible on the website). We have encountered this issue on every PHP version from 5.3 to 5.5 and multiple environments (linux, windows). PHP 5.2 was free from this bug (version switching proved it). The corruption occurs only on some value combinations, for example after we change one of the string values the corruption does not appear, when we changed it back: the corruption occurs again. The type of object does not matter, it often happens for stdClass. Please check an example object, which was used in Test script: https://dl.dropboxusercontent.com/u/11435743/php/load.txt Please compare it with the object which is an output of unserialize function. https://dl.dropboxusercontent.com/u/11435743/php/load_corrupt.txt Clearly one of the values has changed: Instead of "Make-up & Styling", value is now: "Make-up ' Sty Please note that pasting of the corrupt string works only until letter "y", please check the load_corrupt.txt file to see the full string. The corruption may have a various form, it can be an additional letter, changed letter, for example: "Stylid" instead of "Styling". Test script: --------------- file_put_contents('load.txt', $data); // correct object file_put_contents('load_corrupt.txt', serialize(unserialize($data))); // one of the value was changed by unserialize, we serialize it back to save it to file Expected result: ---------------- "make-up-styling";s:4:"name";s:17:"Make-up & Styling" Actual result: -------------- s:15:"make-up-styling";s:4:"name";s:17:"Make-up ' Sty ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=67363&edit=1