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Looks like it might be worth adding a Null check herу too: `HA2.data` is dereferenced without checking for NULL: https://github.com/samizdatco/nginx-http-auth-digest/blob/5a2cae4812d8a1ba5f83dfbcb8d043d05c8e6f97/ngx_http_auth_digest_module.c#L716 `HA1.data` here: https://github.com/samizdatco/nginx-http-auth-digest/blob/5a2cae4812d8a1ba5f83dfbcb8d043d05c8e6f97/ngx_http_auth_digest_module.c#L675 and `auth_fields` here: https://github.com/samizdatco/nginx-http-auth-digest/blob/5a2cae4812d8a1ba5f83dfbcb8d043d05c8e6f97/ngx_http_auth_digest_module.c#L286

I think that a check should be added to the value assigned to the `location` variable.