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Nicolas Grekas:
RFC for a Secure Unserialization Mechanism in PHP
Aug 24, 2018 @ 15:40:04

On his Medium.com site Nicolas Grekas talks about a new RFC that's been proposed to provide a safer method for serializing and unserializing values in native PHP functionality.

PHP serialization/unserialization has several drawbacks. [...] To mitigate these security issues, the unserialize() function handles an allowed_classes option since PHP 7.0. Implementing Serializable has this security-mitigation advantage of allowing authors to filter the allowed classes in the subgraph managed by their objects. This feature is only a mitigation because not all use cases know all the possible classes beforehand.

He starts by listing out some of the issues with both the current implementations of serialization and unserialization in PHP. From there he makes a proposal for some new functionality to help make things a bit more sane:

  • a __serialize magic method
  • a new S type representing serialized data
  • a new __unserialize magic method
  • automatic protection around destructors during the unserialization process

He finishes up the post talking about some of the expected benefits of this kind of functionality and a few of the extra considerations that would need to be thought through as a part of the implementation.

tagged: serialize unserialize rfc proposal functionality overview

Link: https://medium.com/@nicolas.grekas/rfc-for-a-secure-unserialization-mechanism-in-php-ee4c7fd01c88