Using inheritance and dependency injection at the same time

Here is how my application makes a call to the database: Web App -> Business Layer -> Data Layer

Everything is using dependency injection.

For example:

In the controller in my Web app I make a call like this:

await _manager.GetCustomers();

Which goes into my Business Layer:

public class CustomerManager : ICustomerManager
{
    private ICustomerRepo _repository;
    public CustomerManager(ICustomerRepo repository)
    {
        _repository = repository;
    }

    public Task<IList<Customer>> GetCustomers(string name = null)
    {
        return _repository.GetCustomers(name);
    }
}

Which goes into my Data Layer:

public class CustomerRepo : BaseRepo, ICustomerRepo
{
    public CustomerRepo(IConfigurationRoot configRoot) 
    : base(configRoot)
    {
    }

    public Customer Find(int id)
    {
        using (var connection = GetOpenConnection())
        {
            ...
        }
    }
}

The trick here is that CustomerRepo inherits from BaseRepo to be able to use the GetOpenConnection() function. But at the same time BaseRepo needs an IConfigurationRoot injected into it from the web application. How can I do both?

public class BaseRepo
{
    private readonly IConfigurationRoot config;

    public BaseRepo(IConfigurationRoot config)
    {
        this.config = config;
    }

    public SqlConnection GetOpenConnection(bool mars = false)
    {
        string cs = config.GetSection("Data:DefaultConnection:ConnectionString").ToString();
        ...
    }
}