The criteria for doing so have now been met:
* PHP 8.1+ is now the documented minimum, and the 1.42 branch already
enforces this in PHPVersionCheck. (T359868)
* OpenSSL support is also now required. (e4127e5864)
As stated in AbstractPbkdf2Password::canUseOpenSSL(), the version check
is no longer needed because PHP 8.1 requires OpenSSL >= 1.0.2. While the
the master branch may still work on PHP 7.4 for now, it is unlikely that
a site using it would still have a version of OpenSSL older than 1.0.1f.
(For example, WMF stopped using Ubuntu 14.04 "Trusty", which has exactly
that minimum version of OpenSSL, once Canonical started charging for
security updates in 2019.)
The reasons for the version check were:
* Old versions of OpenSSL appeared to perform at least as well as PHP
for reasonably long passwords (up to 128 bytes for SHA-512 hashes);
however, they had the same DoS issue that our own implementation for
PHP 5.3 had (see T64685). hash_pbkdf2() never had that problem.
* If PHP were to incorporate the major optimization of hashing the HMAC
key blocks only once, then the old OpenSSL versions would actually be
slower. So far, this has not happened.
Change-Id: I47eb1aabf3d0ae4792624f9ba1c392880d52d0b7
* Use @phan-var to suppress issues with version independence.
* In Parser strictly compare to false. I still think this is a Phan bug.
Bug: T322278
Change-Id: I654b73e5ed843474ed35c3780d95b04dce388bea
* ForkController, OrderedStreamingForkController: indeed pcntl_fork()
can't return false.
* RL\Image: Specify type instead of using suppression, since the issue
name changes.
* VueComponentParser: Accept complaint about nullable nodeValue.
* Disable PHP 8.0 polyfill stubs when running on PHP 8.0+ to avoid
duplicate interface errors.
* Add Socket stub and use it in LegacyHandler instead of multiple
existing suppressions.
* MemcachedPeclBagOStuff: accept complaint recommending !$result over
$result === false when the type is boolean.
* MemcachedPeclBagOStuff: fix probable bug, ignoring errors from
Memcached::getMulti(). Phan noticed that $res=false was unreachable,
but it should probably be reachable.
* DatabaseMysqli: accept complaint that $this->conn->errno is already
known to be an int. It was probably a hack for some previous version
of Phan.
* BcryptPassword, MWOldPassword, MWSaltedPassword: accept complaint that
the !is_string() checks are unnecessary, after code review of PHP.
* Pbkdf2PasswordUsingHashExtension: note that contrary to Phan's
suggestion, this check is necessary.
* DefaultPreferencesFactory: remove an existing hack for
array_diff_key(), no longer necessary on 7.4 and causes an error on
8.1. Use coalesce instead of cast for the remaining
array_intersect_key() hack since it better shows that we are casting
away null.
* FullSearchResultWidget: fix likely bug involving strict comparison
between a float and an int.
* SpecialWatchlist: accept complaint that $selectedHours is
unconditionally a float, being the return value of round(), and thus
the cast is unnecessary.
* Add stub for AllowDynamicProperties, resolving an error in User.php.
* Xml: accept complaint that $encMonth is already known to be an int.
Six errors remain. These need suppressions or otherwise conflict with
PHP 7.4 support.
Bug: T322278
Change-Id: Ie375bbc8ccf22330b9a169e8da98f2bbe26ec8b9
This at least doubles the speed, which would allow the number of
iterations to be doubled and computation of the password hash to
complete in the same amount of time as before, or maybe even a
slight bit less.
The doubling in speed is due to an optimization[1] that so far has not
been accepted into PHP's hash extension.[2] In addition, OpenSSL has
optimized assembly-language hash function implementations for several
common CPU architectures. These provide a further, yet more slight,
performance improvement.
While OpenSSL's PKCS5_PBKDF2_HMAC() is not the fastest implementation
around, using it does not add a new library dependency. And although
better password hashing functions exist, PBKDF2 is still the default
in MediaWiki. For these reasons, I think this change makes sense.
[1]: https://github.com/openssl/openssl/commit/c10e3f0cffb3820d
[2]: https://github.com/php/php-src/issues/9604
Change-Id: I7b06590d4c42581f8749336f9c17777f973a506c
