Having the ability to replace the logic to validate a username and password against a custom data store is important to some developers. Normally in ASP.Net Core Identity this would require you to override the UmbracoBackOfficeUserManager.CheckPasswordAsync implementation and then replace the UmbracoBackOfficeUserManager with your own class during startup. Since this is a common task we've made this process a lot easier with an interface called IBackOfficeUserPasswordChecker.
Here are the steps to specify your own logic for validating a username and password for the backoffice:
Create an implementation of Umbraco.Cms.Core.Security.IBackOfficeUserPasswordChecker
There is one method in this interface: Task<BackOfficeUserPasswordCheckerResult> CheckPasswordAsync(BackOfficeIdentityUser user, string password);
The result of this method can be 3 things:
ValidCredentials = The credentials entered are valid and the authorization should proceed
InvalidCredentials = The credentials entered are not valid and the authorization process should return an error
FallbackToDefaultChecker = This is an optional result which can be used to fallback to Umbraco's default authorization process if the credentials could not be verified by your own custom implementation
For example, to always allow login when the user enters the password test you could do:
Register the MyPasswordChecker in your Program.cs file:
If the username entered in the login screen does not exist in Umbraco, then MyPasswordChecker() does not run. Instead, Umbraco will immediately fall back to its internal checks, which is the default Umbraco behavior.