I've spent a few days troubleshooting some password validation failures in Laravel 9. Password testperson resolves to hash $2y$10$5xc/wAmNCKV.YhpWOfyNoetCj/r3Fs5TyAskgZuIF/LEItWfm7rPW. A direct query of the corresponding database table confirms that this is the correct hash value. However Laravel's authentication infrastructure rejects this password and refuses authentication.

This is not common. I have multiple passwords that parse correctly. For example, the password eo resolves to $2y$10$uNWYvMVmagIwQ2eXnVKLCOAK1QFQdcRtxbvlghf.Xpg0U1w.N./N2, and Laravel validates the password. The same mechanism creates both user records, although they have different permissions (indicated by a boolean value on the record).

I found a bug in the function password_verify, which was determined to be returning false negatives in this Stack Overflow question and this Treehouse thread.

Specifically, this is the stack in Laravel where this failure point occurs:

• login The route calls \Illuminate\Foundation\Auth\AuthenticatesUsers::login via the controller class.
• login Method calls \Illuminate\Foundation\Auth\AuthenticatesUsers::attemptLogin.
The
• attemptLogin method calls the attempt method of the controller guard object.
• \Illuminate\Auth\SessionGuard::attempt Calls \Illuminate\Auth\SessionGuard::hasValidCredentials.
• \Illuminate\Auth\SessionGuard::hasValidCredentials Calls the validateCredentials method on the guard provider object.
• Illuminate\Auth\EloquentUserProvider::validateCredentials Call the check method on its hasher object.
• Illuminate\Hashing\HashManager::check Calls the check method on its driver.
• Illuminate\Hashing\BcryptHasher::check Calls Illuminate\Hashing\AbstractHasher::check.
• Illuminate\Hashing\AbstractHasher::check Calls password_verify.

After unwinding the entire stack, I run the following code in the login method of the login controller:

$provider = $this->guard()->getProvider();
$credentials =  $this->credentials($request);
$user = $provider->retrieveByCredentials($credentials);
$password_unhashed = $request['password'];
$password_hashed = $user->getAuthPassword();
$password_verify = password_verify($password_unhashed, $password_hashed);
logger('attemping login', compact('password_verify','password_unhashed','password_hashed'));

Dump this context:

{
"password_verify": false,
"password_unhashed": "testperson",
"password_hashed": "yxc/wAmNCKV.YhpWOfyNoetCj/r3Fs5TyAskgZuIF/LEItWfm7rPW"
}

If I put that password into a SELECT users WHERE password= query, I get the users I expect.

How is this going? How can I solve this problem?