Overriding permission required by AbpAuthorize attribute

I get the concept of Permissions, Roles and Authorization. But I can't get a grip of how the Authorization works when added in multiple places. Let me explain.

I have an application service class with the attribute: [AbpAuthorize(PermissionNames.A)] Within that class I have a method with the following attribute: [AbpAuthorize(PermissionNames.B)]

In my world the B-permission should override the A-permission, but does it? To me it does not feel like it. Is there a way for me to accomplish the same functionality? To make it even more complex, the A-permission is a MultiTenancySides.Host permission, and B is not.

Thanks!

In my world the B-permission should override the A-permission, but does it?

No, separate AbpAuthorize attributes are AND condition.

Is there a way for me to accomplish the [override] functionality?

That's fundamentally different. You'll have to rewrite IAuthorizationHelper.

public class OverridingAuthorizationHelper : AuthorizationHelper
{
    public OverridingAuthorizationHelper(IFeatureChecker featureChecker, IAuthorizationConfiguration authConfiguration)
        : base(featureChecker, authConfiguration)
    {
    }

    public override Task AuthorizeAsync(IEnumerable<IAbpAuthorizeAttribute> authorizeAttributes)
    {
        if (authorizeAttributes.Any())
        {
            authorizeAttributes = new List<IAbpAuthorizeAttribute> { authorizeAttributes.First() };
        }

        return base.AuthorizeAsync(authorizeAttributes);
    }
}

And then replace it in the PreInitialize method of your *.Core module.

// using Abp.Configuration.Startup;

public override void PreInitialize()
{
    Configuration.ReplaceService<IAuthorizationHelper, OverridingAuthorizationHelper>();
}