Merge pull request #1 from Simponic/erlang_ssh_server

3 files changed, 89 insertions, 0 deletions

diff --git a/lib/chessh/ssh/daemon.ex b/lib/chessh/ssh/daemon.ex
new file mode 100644
index 0000000..9f17f75
--- /dev/null
+++ b/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
diff --git a/lib/chessh/ssh/server.ex b/lib/chessh/ssh/server.ex
deleted file mode 100644
index e69de29..0000000
--- a/lib/chessh/ssh/server.ex
+++ /dev/null
diff --git a/lib/chessh/ssh/server_key.ex b/lib/chessh/ssh/server_key.ex
new file mode 100644
index 0000000..72a4fbb
--- /dev/null
+++ b/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