From 10bc34245e8e1e3ba63fb0720d3bcfb1119db921 Mon Sep 17 00:00:00 2001
From: Simponic <loganhunt@simponic.xyz>
Date: Tue, 27 Dec 2022 23:50:22 -0700
Subject: Initial erlang stuff

---
 lib/chessh/application.ex    |  2 +-
 lib/chessh/auth/password.ex  |  3 +--
 lib/chessh/schema/key.ex     |  3 +--
 lib/chessh/ssh/daemon.ex     | 60 ++++++++++++++++++++++++++++++++++++++++++++
 lib/chessh/ssh/server.ex     |  0
 lib/chessh/ssh/server_key.ex | 11 ++++++++
 6 files changed, 74 insertions(+), 5 deletions(-)
 create mode 100644 lib/chessh/ssh/daemon.ex
 delete mode 100644 lib/chessh/ssh/server.ex
 create mode 100644 lib/chessh/ssh/server_key.ex

(limited to 'lib')

diff --git a/lib/chessh/application.ex b/lib/chessh/application.ex
index c760532..847dd98 100644
--- a/lib/chessh/application.ex
+++ b/lib/chessh/application.ex
@@ -2,7 +2,7 @@ defmodule Chessh.Application do
   use Application
 
   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)
   end
diff --git a/lib/chessh/auth/password.ex b/lib/chessh/auth/password.ex
index 8a6c683..c3b03f5 100644
--- a/lib/chessh/auth/password.ex
+++ b/lib/chessh/auth/password.ex
@@ -1,6 +1,5 @@
 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
diff --git a/lib/chessh/schema/key.ex b/lib/chessh/schema/key.ex
index 765c83b..adf018d 100644
--- a/lib/chessh/schema/key.ex
+++ b/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
diff --git a/lib/chessh/ssh/daemon.ex b/lib/chessh/ssh/daemon.ex
new file mode 100644
index 0000000..acb6bea
--- /dev/null
+++ b/lib/chessh/ssh/daemon.ex
@@ -0,0 +1,60 @@
+defmodule Chessh.SSH.Daemon do
+  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, _address, attempts) do
+    if Chessh.Auth.PasswordAuthenticator.authenticate(username, password) do
+      true
+    else
+      newAttempts =
+        case attempts do
+          :undefined -> 0
+          _ -> attempts
+        end
+
+      if Application.fetch_env!(:chessh, :max_password_attempts) <= newAttempts do
+        :disconnect
+      else
+        {false, newAttempts + 1}
+      end
+    end
+  end
+
+  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,
+           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
diff --git a/lib/chessh/ssh/server_key.ex b/lib/chessh/ssh/server_key.ex
new file mode 100644
index 0000000..1096e09
--- /dev/null
+++ b/lib/chessh/ssh/server_key.ex
@@ -0,0 +1,11 @@
+defmodule Chessh.SSH.ServerKey do
+  @behaviour :ssh_server_key_api
+
+  def is_auth_key(key, username, _daemon_options) do
+    Chessh.Auth.KeyAuthenticator.authenticate(username, key)
+  end
+
+  def host_key(algorithm, daemon_options) do
+    :ssh_file.host_key(algorithm, daemon_options)
+  end
+end
-- 
cgit v1.2.3-70-g09d2