Access Control
for the
Swarm

Geovane Fedrecheski

Advisor: Marcelo Zuffo

Nov 2016

Contents

  • Swarm?

  • Access Control?

  • Swarm Broker & Access Control

  • Prototype

  • Conclusion & Next steps

The Swarm

First, the IoT

Good

  • Automation
  • Pervasive
  • Remote access

Bad

  • Interoperability
  • Scalability
  • Security

Lee, Edward A., et al. "The Swarm at the Edge of the Cloud." IEEE Design & Test 31.3 (2014): 8-20.

Challenges

Distributed

Scale

Dynamic

Adaptative

Heterogeneous

Safe
Secure

Security

Key Management

Attacks

Energy Consumption

Authentication

Access Control

Access Control

NIST IR 7316 2006

Access control is concerned with providing users with selective access to resources.

NIST SP 800-162 2014

The Purpose of Logical Access Control is to protect objects from unauthorized operations.

Access Control System

3 Abstractions:

¬(p ∧ q)

Policies

Mechanism

Model

Types of
Access Control Systems

Access Control List (ACL)

Role-based Access Control (RBAC)

Attribute-based Access Control (ABAC)

Access Control List (ACL)

resource  user:op
------------------
/tmp      pablo:rw
file.txt  pablo:r
/         root:rwx

Role-based (RBAC)

Attribute-based (ABAC)

Attribute-based (ABAC)

Swarm Broker
&
Access Control

The Swarm at the Edge of the Cloud

Swarm Broker

The Swarm Broker

Swarm Access Control

  • Attribute-based (ABAC)

  • Initially based on oneM2M specs

  • Very similar to XACML

Swarm Access Control

¬(p ∧ q)

Policies

Mechanism

Model

Policies

{
  "id": "1",
  "name": "policy 1",
  "privileges": [
    {
      "originators": [
        "john",
        "rick"
      ],
      "operations": 4,
      "contexts": [
        {"time_window": ["* * 6-22 * * *"]}
      ],
      "targets": [
        "indoorsensor/*",
        "indoorsensor/*",
        "outdoorsensor/temperature"
      ]
    }
  ]
}

Mechanism

Policy Enforcement

{from=X
 op=read
 to=Y/value}
GET /value
origin: X

originators: ["Z", "X"],
operations: 0x02
targets: ["Y/*"]

Mechanism

(ABAC terminology)

Policy Enforcement Point
(PEP)

Policy Decision Point
(PDP)

Policy Information Point
(PIP)

Policy
Administration
 Point
(PAP)

Mechanism

Policy Management

Prototype

Goal:
Single Board Computers

Development & Testing:
Linux Containers

Platform

Communication

  • TCP/HTTP

  • REST architecture

Language:

both Java and Elixir

Elixir libraries

Cowboy webserver

defmodule Sensor.Router do
  use Plug.Router

  plug :match
  plug Plug.Parsers, parsers: [:json], json_decoder: Poison
  plug :fetch_sd_params
  plug BrokerHTTPClient, :authorize
  plug :dispatch

  get "/temperature-sensor/value" do
    value = Handler.read |> Float.round(1)

    resp =
      %{"value" => value, "unit" => "celsius"}
      |> Poison.encode!

    send_resp(conn, 200, resp)
  end
end
defmodule BrokerHTTPClient do
  def authorize(conn, _opts) do
    params = fetch_authz_params(conn)
    Logger.info "Called PEP with #{inspect params}"
    broker_access_control = 
      conn.assigns[:broker_url] <> @authorize_path

    resp = HTTPoison.get(broker_access_control, [], params: params)
    if allowed?(resp) do
      conn
    else
      send_resp(conn, 401, "") |> halt
    end
  end
end
defmodule BrokerHTTP.Router do
  use BrokerHTTP.Web, :router

  pipeline :api do
    plug :accepts, ["json"]
  end

  scope "/broker", BrokerHTTP do
    pipe_through :api

    resources "/registry", RegistryController, only: [:index, :create, :show]

    resources "/locate-requests", LocateController, only: [:create] do
      resources "/candidates", CandidateController, only: [:index, :create, :show]
    end

    get "/security/authorize-request", AccessControlController, :index

    resources "/security/policies", PolicyController
  end
end
defmodule BrokerHTTP.AccessControlController do
  use BrokerHTTP.Web, :controller
  alias Plug.Conn.Status

  def index(conn, %{"fr" => from, "to" => to, "op" => op}) do
    req = %Request{from: from, to: to, op: String.to_integer(op), id: nil}

    status = if Broker.AccessControl.authorize(req) do
      Status.code(:ok)
    else
      Status.code(:unauthorized)
    end

    send_resp conn, status, ""
  end
end
defmodule Broker.AccessControl.PDP do
  def authorize(request) do
    acp_rules = PRP.get_applicable_acp request

    decision = Enum.reduce(acp_rules, false, fn(rule, acc) ->
      acc || match(rule, request)
    end)
    Logger.info "Authorizing request #{inspect request} resulted in #{decision}"
    decision
  end

  def match(rule, %Request{} = request) do
    match_origs(rule, request)
    && match_ops(rule, request)
    && match_targets(rule, request)
    && match_ctxs(rule, PIP.fetch_context(request))
  end
end

Policy Manager

defmodule BrokerHTTP.Router do
  use BrokerHTTP.Web, :router

  pipeline :api do
    plug :accepts, ["json"]
  end

  scope "/broker", BrokerHTTP do
    pipe_through :api

    resources "/registry", RegistryController, only: [:index, :create, :show]

    resources "/locate-requests", LocateController, only: [:create] do
      resources "/candidates", CandidateController, only: [:index, :create, :show]
    end

    get "/security/authorize-request", AccessControlController, :index

    resources "/security/policies",
      PolicyController,
      only: [:index, :create, :show, :update, :delete]
  end
end

Policy Manager

Demo

Conclusion

Goal: a secure Swarm

Access Control

prototype

Policy Manager

prototype

+

Next steps

Goal: a secure Swarm

  • Authentication

  • Improve Policy Manager & UI

  • Next Generation Access Control (NGAC)

Obrigado!

Geovane Fedrecheski
geonnave@gmail.com


Advisor: Marcelo Zuffo

Nov 2016

Access Control
for the
Swarm

Access Control for the Swarm

By Geovane Fedrecheski

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Access Control for the Swarm

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