Merge pull request #1 from Simponic/erlang_ssh_server

.env

@@ -0,0 +1 @@
+NODE_ID=node-one

.env.example

@@ -0,0 +1 @@
+NODE_ID=aUniqueString

.github/workflows/elixir.yml

@@ -10,9 +10,9 @@ on:
   pull_request:
     branches: [ "main" ]  # adapt branch for project
 
-# Sets the ENV `MIX_ENV` to `test` for running tests
 env:
   MIX_ENV: test
+  NODE_ID: aUniqueString
 
 jobs:
   test:

README.md

@@ -1,2 +1,5 @@
 # CheSSH
 
+Features:
+- [X] SSH Key & Password authentication
+- [ ] Rate limiting

config/config.exs

@@ -2,8 +2,17 @@ import Config
 
 config :chessh,
   ecto_repos: [Chessh.Repo],
-  priv_dir: Path.join(Path.dirname(__DIR__), "priv/keys"),
-  port: 42069,
+  key_dir: Path.join(Path.dirname(__DIR__), "priv/keys"),
+  port: 42_069,
   max_sessions: 255
 
+config :chessh, RateLimits,
+  jail_timeout_ms: 5 * 60 * 1000,
+  jail_attempt_threshold: 15,
+  max_concurrent_user_sessions: 5
+
+# This will be redis when scaled across multiple nodes
+config :hammer,
+  backend: {Hammer.Backend.ETS, [expiry_ms: 60_000 * 60 * 4, cleanup_interval_ms: 60_000 * 10]}
+
 import_config "#{config_env()}.exs"

config/test.exs

@@ -1,5 +1,9 @@
 import Config
 
+config :chessh, RateLimits,
+  jail_timeout_ms: 5000,
+  jail_attempt_threshold: 3
+
 config :chessh, Chessh.Repo,
   database: "chessh-test",
   username: "postgres",
@@ -8,4 +12,4 @@ config :chessh, Chessh.Repo,
   pool: Ecto.Adapters.SQL.Sandbox
 
 config :chessh,
-  priv_dir: Path.join(Path.dirname(__DIR__), "priv/keys")
+  key_dir: Path.join(Path.dirname(__DIR__), "priv/test_keys")

lib/chessh/application.ex

@@ -1,9 +1,23 @@
 defmodule Chessh.Application do
+  alias Chessh.{PlayerSession, Node}
   use Application
 
+  def initialize_player_sessions_on_node() do
+    # If we have more than one node running the ssh daemon, we'd want to ensure
+    # this is restarting after every potential crash. Otherwise the player sessions
+    # on the node would hang.
+    node_id = System.fetch_env!("NODE_ID")
+    Node.boot(node_id)
+    PlayerSession.delete_all_on_node(node_id)
+  end
+
   def start(_, _) do
-    children = [Chessh.Repo]
+    children = [Chessh.Repo, Chessh.SSH.Daemon]
     opts = [strategy: :one_for_one, name: Chessh.Supervisor]
-    Supervisor.start_link(children, opts)
+
+    with {:ok, pid} <- Supervisor.start_link(children, opts) do
+      initialize_player_sessions_on_node()
+      {:ok, pid}
+    end
   end
 end

lib/chessh/auth/password.ex

@@ -1,10 +1,9 @@
 defmodule Chessh.Auth.PasswordAuthenticator do
-  alias Chessh.Player
-  alias Chessh.Repo
+  alias Chessh.{Player, Repo}
 
   def authenticate(username, password) do
-    case Repo.get_by(Player, username: String.Chars.to_string(username)) do
-      x -> Player.valid_password?(x, String.Chars.to_string(password))
+    case Repo.get_by(Player, username: username) do
+      x -> Player.valid_password?(x, password)
     end
   end
 end

lib/chessh/schema/key.ex

@@ -16,7 +16,7 @@ defmodule Chessh.Key do
     |> cast(update_encode_key(attrs, :key), [:key])
     |> cast(attrs, [:name])
     |> validate_required([:key, :name])
-    |> validate_format(:key, ~r/[\-\w\d]+ [^ ]+$/, message: "invalid ssh key")
+    |> validate_format(:key, ~r/[\-\w\d]+ [^ ]+$/, message: "invalid public ssh key")
     |> validate_format(:key, ~r/^(?!ssh-dss).+/, message: "DSA keys are not supported")
   end
 
@@ -41,7 +41,6 @@ defmodule Chessh.Key do
     end
     # Remove comment at end of key
     |> String.replace(~r/ [^ ]+\@[^ ]+$/, "")
-    # Remove potential spaces / newline
     |> String.trim()
   end
 end

lib/chessh/schema/node.ex

@@ -0,0 +1,24 @@
+defmodule Chessh.Node do
+  alias Chessh.Repo
+  import Ecto.Changeset
+  use Ecto.Schema
+
+  @primary_key {:id, :string, []}
+  schema "nodes" do
+    field(:last_start, :utc_datetime)
+  end
+
+  def changeset(node, attrs) do
+    node
+    |> cast(attrs, [:last_start])
+  end
+
+  def boot(node_id) do
+    case Repo.get(Chessh.Node, node_id) do
+      nil -> %Chessh.Node{id: node_id}
+      node -> node
+    end
+    |> Chessh.Node.changeset(%{last_start: DateTime.utc_now()})
+    |> Repo.insert_or_update()
+  end
+end

lib/chessh/schema/player_session.ex

@@ -0,0 +1,34 @@
+defmodule Chessh.PlayerSession do
+  alias Chessh.Repo
+  use Ecto.Schema
+  import Ecto.{Query, Changeset}
+
+  schema "player_sessions" do
+    field(:login, :utc_datetime)
+
+    belongs_to(:node, Chessh.Node, type: :string)
+    belongs_to(:player, Chessh.Player)
+  end
+
+  def changeset(player_session, attrs) do
+    player_session
+    |> cast(attrs, [:login])
+  end
+
+  def concurrent_sessions(player) do
+    Repo.aggregate(
+      from(p in Chessh.PlayerSession,
+        where: p.player_id == ^player.id
+      ),
+      :count
+    )
+  end
+
+  def delete_all_on_node(node_id) do
+    Repo.delete_all(
+      from(p in Chessh.PlayerSession,
+        where: p.node_id == ^node_id
+      )
+    )
+  end
+end

lib/chessh/ssh/daemon.ex

@@ -0,0 +1,77 @@
+defmodule Chessh.SSH.Daemon do
+  alias Chessh.Auth.PasswordAuthenticator
+  use GenServer
+
+  def start_link(_) do
+    GenServer.start_link(__MODULE__, %{
+      pid: nil
+    })
+  end
+
+  def init(state) do
+    GenServer.cast(self(), :start)
+    {:ok, state}
+  end
+
+  def pwd_authenticate(username, password) do
+    # TODO - check concurrent sessions
+    PasswordAuthenticator.authenticate(
+      String.Chars.to_string(username),
+      String.Chars.to_string(password)
+    )
+  end
+
+  def pwd_authenticate(username, password, inet) do
+    [jail_timeout_ms, jail_attempt_threshold] =
+      Application.get_env(:chessh, RateLimits)
+      |> Keyword.take([:jail_timeout_ms, :jail_attempt_threshold])
+      |> Keyword.values()
+
+    {ip, _port} = inet
+    rateId = "failed_password_attempts:#{Enum.join(Tuple.to_list(ip), ".")}"
+
+    if pwd_authenticate(username, password) do
+      true
+    else
+      case Hammer.check_rate_inc(rateId, jail_timeout_ms, jail_attempt_threshold, 1) do
+        {:allow, _count} ->
+          false
+
+        {:deny, _limit} ->
+          :disconnect
+      end
+    end
+  end
+
+  def pwd_authenticate(username, password, inet, _address),
+    do: pwd_authenticate(username, password, inet)
+
+  def handle_cast(:start, state) do
+    port = Application.fetch_env!(:chessh, :port)
+    key_dir = String.to_charlist(Application.fetch_env!(:chessh, :key_dir))
+    max_sessions = Application.fetch_env!(:chessh, :max_sessions)
+
+    case :ssh.daemon(
+           port,
+           system_dir: key_dir,
+           pwdfun: &pwd_authenticate/4,
+           key_cb: Chessh.SSH.ServerKey,
+           #          disconnectfun: 
+           id_string: :random,
+           subsystems: [],
+           parallel_login: true,
+           max_sessions: max_sessions
+         ) do
+      {:ok, pid} ->
+        Process.link(pid)
+        {:noreply, %{state | pid: pid}, :hibernate}
+
+      {:error, err} ->
+        raise inspect(err)
+    end
+
+    {:noreply, state}
+  end
+
+  def handle_info(_, state), do: {:noreply, state}
+end

lib/chessh/ssh/server_key.ex

@@ -0,0 +1,12 @@
+defmodule Chessh.SSH.ServerKey do
+  alias Chessh.Auth.KeyAuthenticator
+  @behaviour :ssh_server_key_api
+
+  def is_auth_key(key, username, _daemon_options) do
+    KeyAuthenticator.authenticate(username, key)
+  end
+
+  def host_key(algorithm, daemon_options) do
+    :ssh_file.host_key(algorithm, daemon_options)
+  end
+end

mix.exs

@@ -31,7 +31,8 @@ defmodule Chessh.MixProject do
       {:ecto, "~> 3.9"},
       {:ecto_sql, "~> 3.9"},
       {:postgrex, "~> 0.16.5"},
-      {:bcrypt_elixir, "~> 3.0"}
+      {:bcrypt_elixir, "~> 3.0"},
+      {:hammer, "~> 6.1"}
     ]
   end
 

mix.lock

@@ -8,7 +8,10 @@
   "ecto": {:hex, :ecto, "3.9.2", "017db3bc786ff64271108522c01a5d3f6ba0aea5c84912cfb0dd73bf13684108", [:mix], [{:decimal, "~> 1.6 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "21466d5177e09e55289ac7eade579a642578242c7a3a9f91ad5c6583337a9d15"},
   "ecto_sql": {:hex, :ecto_sql, "3.9.1", "9bd5894eecc53d5b39d0c95180d4466aff00e10679e13a5cfa725f6f85c03c22", [:mix], [{:db_connection, "~> 2.5 or ~> 2.4.1", [hex: :db_connection, repo: "hexpm", optional: false]}, {:ecto, "~> 3.9.0", [hex: :ecto, repo: "hexpm", optional: false]}, {:myxql, "~> 0.6.0", [hex: :myxql, repo: "hexpm", optional: true]}, {:postgrex, "~> 0.16.0 or ~> 1.0", [hex: :postgrex, repo: "hexpm", optional: true]}, {:tds, "~> 2.1.1 or ~> 2.2", [hex: :tds, repo: "hexpm", optional: true]}, {:telemetry, "~> 0.4.0 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "5fd470a4fff2e829bbf9dcceb7f3f9f6d1e49b4241e802f614de6b8b67c51118"},
   "elixir_make": {:hex, :elixir_make, "0.7.2", "e83548b0500e654d1a595f1134af4862a2e92ec3282ec4c2a17641e9aa45ee73", [:mix], [{:castore, "~> 0.1", [hex: :castore, repo: "hexpm", optional: true]}], "hexpm", "05fb44abf9582381c2eb1b73d485a55288c581071de0ee3ee1084ee69d6a8e5f"},
+  "erlex": {:hex, :erlex, "0.2.6", "c7987d15e899c7a2f34f5420d2a2ea0d659682c06ac607572df55a43753aa12e", [:mix], [], "hexpm", "2ed2e25711feb44d52b17d2780eabf998452f6efda104877a3881c2f8c0c0c75"},
   "esshd": {:hex, :esshd, "0.2.1", "cded6a329c32bc3b3c15828bcd34203227bbef310db3c39a6f3c55cf5b29cd34", [:mix], [], "hexpm", "b058b56af53aba1c23522d72a3c39ab7f302e509af1c0ba1a748f00d93053c4d"},
+  "hammer": {:hex, :hammer, "6.1.0", "f263e3c3e9946bd410ea0336b2abe0cb6260af4afb3a221e1027540706e76c55", [:make, :mix], [{:poolboy, "~> 1.5", [hex: :poolboy, repo: "hexpm", optional: false]}], "hexpm", "b47e415a562a6d072392deabcd58090d8a41182cf9044cdd6b0d0faaaf68ba57"},
+  "poolboy": {:hex, :poolboy, "1.5.2", "392b007a1693a64540cead79830443abf5762f5d30cf50bc95cb2c1aaafa006b", [:rebar3], [], "hexpm", "dad79704ce5440f3d5a3681c8590b9dc25d1a561e8f5a9c995281012860901e3"},
   "postgrex": {:hex, :postgrex, "0.16.5", "fcc4035cc90e23933c5d69a9cd686e329469446ef7abba2cf70f08e2c4b69810", [:mix], [{:connection, "~> 1.1", [hex: :connection, repo: "hexpm", optional: false]}, {:db_connection, "~> 2.1", [hex: :db_connection, repo: "hexpm", optional: false]}, {:decimal, "~> 1.5 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:table, "~> 0.1.0", [hex: :table, repo: "hexpm", optional: true]}], "hexpm", "edead639dc6e882618c01d8fc891214c481ab9a3788dfe38dd5e37fd1d5fb2e8"},
   "telemetry": {:hex, :telemetry, "1.1.0", "a589817034a27eab11144ad24d5c0f9fab1f58173274b1e9bae7074af9cbee51", [:rebar3], [], "hexpm", "b727b2a1f75614774cff2d7565b64d0dfa5bd52ba517f16543e6fc7efcc0df48"},
 }

priv/repo/migrations/20221229225556_add_node.exs

@@ -0,0 +1,10 @@
+defmodule Chessh.Repo.Migrations.AddNode do
+  use Ecto.Migration
+
+  def change do
+    create table(:nodes, primary_key: false) do
+      add(:id, :string, primary_key: true)
+      add(:last_start, :utc_datetime)
+    end
+  end
+end

priv/repo/migrations/20221229225559_add_user_session.exs

@@ -0,0 +1,11 @@
+defmodule Chessh.Repo.Migrations.AddUserSession do
+  use Ecto.Migration
+
+  def change do
+    create table(:player_sessions) do
+      add(:login, :utc_datetime)
+      add(:player_id, references(:players))
+      add(:node_id, references(:nodes, type: :string))
+    end
+  end
+end

priv/test_keys/client_keys/.gitignore

@@ -0,0 +1 @@
+known_hosts

priv/test_keys/client_keys/id_ed25519

@@ -0,0 +1,7 @@
+-----BEGIN OPENSSH PRIVATE KEY-----
+b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAAAMwAAAAtzc2gtZW
+QyNTUxOQAAACDyhmROJ9PPZsBpG46n+FCLn+mP0nncwSPgXO9xRRsKPQAAAJAJnUS4CZ1E
+uAAAAAtzc2gtZWQyNTUxOQAAACDyhmROJ9PPZsBpG46n+FCLn+mP0nncwSPgXO9xRRsKPQ
+AAAEBjR5Cy8SHUtrIf6aHJGXA/kgesZzxxjH15E4wj1DESh/KGZE4n089mwGkbjqf4UIuf
+6Y/SedzBI+Bc73FFGwo9AAAABm5vbmFtZQECAwQFBgc=
+-----END OPENSSH PRIVATE KEY-----

priv/test_keys/client_keys/id_ed25519.pub

@@ -0,0 +1 @@
+ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIPKGZE4n089mwGkbjqf4UIuf6Y/SedzBI+Bc73FFGwo9

test/auth/password_test.exs

@@ -1,27 +1,27 @@
 defmodule Chessh.Auth.PasswordAuthenticatorTest do
   use ExUnit.Case
-  alias Chessh.Player
-  alias Chessh.Repo
+  alias Chessh.{Player, Repo}
 
   @valid_user %{username: "logan", password: "password"}
 
-  setup do
-    :ok = Ecto.Adapters.SQL.Sandbox.checkout(Chessh.Repo)
+  setup_all do
+    Ecto.Adapters.SQL.Sandbox.checkout(Repo)
+    Ecto.Adapters.SQL.Sandbox.mode(Repo, {:shared, self()})
 
     {:ok, _user} = Repo.insert(Player.registration_changeset(%Player{}, @valid_user))
 
     :ok
   end
 
-  test "User can sign in with their password" do
+  test "Password can authenticate a hashed password" do
     assert Chessh.Auth.PasswordAuthenticator.authenticate(
-             String.to_charlist(@valid_user.username),
-             String.to_charlist(@valid_user.password)
+             @valid_user.username,
+             @valid_user.password
            )
 
     refute Chessh.Auth.PasswordAuthenticator.authenticate(
-             String.to_charlist(@valid_user.username),
-             String.to_charlist("a_bad_password")
+             @valid_user.username,
+             "a_bad_password"
            )
   end
 end

test/auth/pubkey_test.exs

@@ -1,8 +1,6 @@
 defmodule Chessh.Auth.PublicKeyAuthenticatorTest do
   use ExUnit.Case
-  alias Chessh.Key
-  alias Chessh.Repo
-  alias Chessh.Player
+  alias Chessh.{Key, Repo, Player}
 
   @valid_user %{username: "logan", password: "password"}
   @valid_key %{
@@ -10,8 +8,9 @@ defmodule Chessh.Auth.PublicKeyAuthenticatorTest do
     key: "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIJ/2LOJGGEd/dhFgRxJ5MMv0jJw4s4pA8qmMbZyulN44"
   }
 
-  setup do
-    :ok = Ecto.Adapters.SQL.Sandbox.checkout(Chessh.Repo)
+  setup_all do
+    Ecto.Adapters.SQL.Sandbox.checkout(Repo)
+    Ecto.Adapters.SQL.Sandbox.mode(Repo, {:shared, self()})
 
     {:ok, player} = Repo.insert(Player.registration_changeset(%Player{}, @valid_user))
 

test/schema/register_test.exs

@@ -1,8 +1,7 @@
 defmodule Chessh.Auth.UserRegistrationTest do
   use Chessh.RepoCase
   use ExUnit.Case
-  alias Chessh.Player
-  alias Chessh.Repo
+  alias Chessh.{Player, Repo}
 
   @valid_user %{username: "logan", password: "password"}
   @invalid_username %{username: "a", password: "password"}

test/ssh/ssh_auth_test.exs

@@ -0,0 +1,83 @@
+defmodule Chessh.SSH.AuthTest do
+  use ExUnit.Case
+  alias Chessh.{Player, Repo, Key}
+
+  @localhost '127.0.0.1'
+  @localhost_inet {{127, 0, 0, 1}, 1}
+  @key_name "The Gamer Machine"
+  @valid_user %{username: "logan", password: "password"}
+  @client_test_keys_dir Path.join(Application.compile_env!(:chessh, :key_dir), "client_keys")
+  @client_pub_key 'id_ed25519.pub'
+
+  setup_all do
+    Ecto.Adapters.SQL.Sandbox.checkout(Repo)
+    Ecto.Adapters.SQL.Sandbox.mode(Repo, {:shared, self()})
+
+    {:ok, player} = Repo.insert(Player.registration_changeset(%Player{}, @valid_user))
+
+    {:ok, key_text} = File.read(Path.join(@client_test_keys_dir, @client_pub_key))
+
+    {:ok, _key} =
+      Repo.insert(
+        Key.changeset(%Key{}, %{key: key_text, name: @key_name})
+        |> Ecto.Changeset.put_assoc(:player, player)
+      )
+
+    :ok
+  end
+
+  test "Password attempts are rate limited" do
+    jail_attempt_threshold =
+      Application.get_env(:chessh, RateLimits)
+      |> Keyword.get(:jail_attempt_threshold)
+
+    assert :disconnect ==
+             Enum.reduce(
+               0..(jail_attempt_threshold + 1),
+               fn _, _ ->
+                 Chessh.SSH.Daemon.pwd_authenticate(
+                   @valid_user.username,
+                   "wrong_password",
+                   @localhost_inet
+                 )
+               end
+             )
+  end
+
+  test "INTEGRATION - Can ssh into daemon with password or public key" do
+    {:ok, sup} = Task.Supervisor.start_link()
+    test_pid = self()
+
+    Task.Supervisor.start_child(sup, fn ->
+      {:ok, _pid} =
+        :ssh.connect(@localhost, Application.fetch_env!(:chessh, :port),
+          user: String.to_charlist(@valid_user.username),
+          password: String.to_charlist(@valid_user.password),
+          auth_methods: 'password',
+          silently_accept_hosts: true
+        )
+
+      send(test_pid, :connected_via_password)
+    end)
+
+    Task.Supervisor.start_child(sup, fn ->
+      {:ok, _pid} =
+        :ssh.connect(@localhost, Application.fetch_env!(:chessh, :port),
+          user: String.to_charlist(@valid_user.username),
+          auth_methods: 'publickey',
+          silently_accept_hosts: true,
+          user_dir: String.to_charlist(@client_test_keys_dir)
+        )
+
+      send(test_pid, :connected_via_public_key)
+    end)
+
+    assert_receive(:connected_via_password, 500)
+    assert_receive(:connected_via_public_key, 500)
+  end
+
+  # TODO
+  #  test "INTEGRATION - User cannot have more than specified concurrent sessions" do
+  #    :ok
+  #  end
+end