Streamline SSL experience

lib/myxql.ex

@@ -16,8 +16,7 @@ defmodule MyXQL do
           | {:password, String.t() | nil}
           | {:charset, String.t() | nil}
           | {:collation, String.t() | nil}
-          | {:ssl, boolean()}
-          | {:ssl_opts, [:ssl.tls_client_option()]}
+          | {:ssl, boolean | [:ssl.tls_client_option()]}
           | {:connect_timeout, timeout()}
           | {:handshake_timeout, timeout()}
           | {:ping_timeout, timeout()}
@@ -70,9 +69,10 @@ defmodule MyXQL do
     * `:collation` - A connection collation. Must be given with `:charset` option, and if set
       it overwrites the default collation for the given charset. (default: `nil`)
 
-    * `:ssl` - Set to `true` if SSL should be used (default: `false`)
-
-    * `:ssl_opts` - A list of SSL options, see `:ssl.connect/2` (default: `[]`)
+    * `:ssl` - Enables SSL. Setting it to `true` enables SSL without server certificate verification,
+      which emits a warning. Instead, prefer to set it to a keyword list, with either
+      `:cacerts` or `:cacertfile` set to a CA trust store, to enable server certificate
+      verification. (default: `false`)
 
     * `:connect_timeout` - Socket connect timeout in milliseconds (default:
       `15_000`)
@@ -127,6 +127,11 @@ defmodule MyXQL do
       iex> {:ok, pid} = MyXQL.start_link(protocol: :tcp)
       {:ok, #PID<0.69.0>}
 
+  Start connection with SSL using CA certificate file:
+
+      iex> {:ok, pid} = MyXQL.start_link(ssl: [cacertfile: System.fetch_env!("DB_CA_CERT_FILE")])
+      {:ok, #PID<0.69.0>}
+
   Run a query after connection has been established:
 
       iex> {:ok, pid} = MyXQL.start_link(after_connect: &MyXQL.query!(&1, "SET time_zone = '+00:00'"))

lib/myxql/client.ex

@@ -20,7 +20,6 @@ defmodule MyXQL.Client do
       :username,
       :password,
       :database,
-      :ssl?,
       :ssl_opts,
       :connect_timeout,
       :handshake_timeout,
@@ -36,15 +35,32 @@ defmodule MyXQL.Client do
     def new(opts) do
       {address, port} = address_and_port(opts)
 
+      {ssl_opts, opts} =
+        case Keyword.pop(opts, :ssl, false) do
+          {false, opts} ->
+            {nil, opts}
+
+          {true, opts} ->
+            Logger.warning(
+              "setting ssl: true on your database connection offers only limited protection, " <>
+                "as the server's certificate is not verified. Set \"ssl: [cacertfile: \"/path/to/cacert.crt\"]\" instead"
+            )
+
+            # Read ssl_opts for backwards compatibility
+            Keyword.pop(opts, :ssl_opts, [])
+
+          {ssl_opts, opts} when is_list(ssl_opts) ->
+            {Keyword.merge(default_ssl_opts(), ssl_opts), opts}
+        end
+
       %__MODULE__{
         address: address,
         port: port,
         username:
           Keyword.get(opts, :username, System.get_env("USER")) || raise(":username is missing"),
         password: nilify(Keyword.get(opts, :password, System.get_env("MYSQL_PWD"))),
         database: Keyword.get(opts, :database),
-        ssl?: Keyword.get(opts, :ssl, false),
-        ssl_opts: Keyword.get(opts, :ssl_opts, []),
+        ssl_opts: ssl_opts,
         connect_timeout: Keyword.get(opts, :connect_timeout, @default_timeout),
         handshake_timeout: Keyword.get(opts, :handshake_timeout, @default_timeout),
         socket_options: (opts[:socket_options] || []) ++ @sock_opts,
@@ -54,6 +70,15 @@ defmodule MyXQL.Client do
       }
     end
 
+    defp default_ssl_opts do
+      [
+        verify: :verify_peer,
+        customize_hostname_check: [
+          match_fun: :public_key.pkix_verify_hostname_match_fun(:https)
+        ]
+      ]
+    end
+
     defp nilify(""), do: nil
     defp nilify(other), do: other
 
@@ -379,9 +404,20 @@ defmodule MyXQL.Client do
     com_query(client, "SET NAMES '#{charset}' COLLATE '#{collation}'")
   end
 
-  defp maybe_upgrade_to_ssl(client, %{ssl?: true} = config, capability_flags, sequence_id) do
+  defp maybe_upgrade_to_ssl(client, %{ssl_opts: nil}, _capability_flags, sequence_id) do
+    {:ok, sequence_id, client}
+  end
+
+  defp maybe_upgrade_to_ssl(client, %{ssl_opts: ssl_opts} = config, capability_flags, sequence_id) do
     {_, sock} = client.sock
 
+    ssl_opts =
+      if is_list(config.address) do
+        Keyword.put_new(ssl_opts, :server_name_indication, config.address)
+      else
+        ssl_opts
+      end
+
     ssl_request =
       ssl_request(
         capability_flags: capability_flags,
@@ -392,15 +428,11 @@ defmodule MyXQL.Client do
     payload = encode_ssl_request(ssl_request)
 
     with :ok <- send_packet(client, payload, sequence_id),
-         {:ok, ssl_sock} <- :ssl.connect(sock, config.ssl_opts, config.connect_timeout) do
+         {:ok, ssl_sock} <- :ssl.connect(sock, ssl_opts, config.connect_timeout) do
       {:ok, sequence_id + 1, %{client | sock: {:ssl, ssl_sock}}}
     end
   end
 
-  defp maybe_upgrade_to_ssl(client, %{ssl?: false}, _capability_flags, sequence_id) do
-    {:ok, sequence_id, client}
-  end
-
   defp recv_handshake(client) do
     recv_packet(client, &decode_initial_handshake/1)
   end
@@ -477,7 +509,7 @@ defmodule MyXQL.Client do
 
   defp perform_full_auth(client, config, "caching_sha2_password", auth_plugin_data, sequence_id) do
     auth_response =
-      if config.ssl? do
+      if config.ssl_opts do
         [config.password, 0]
       else
         # request public key

lib/myxql/protocol.ex

@@ -179,9 +179,9 @@ defmodule MyXQL.Protocol do
         :client_transactions
       ])
       |> maybe_put_capability_flag(:client_connect_with_db, !is_nil(config.database))
-      |> maybe_put_capability_flag(:client_ssl, config.ssl?)
+      |> maybe_put_capability_flag(:client_ssl, is_list(config.ssl_opts))
 
-    if config.ssl? && !has_capability_flag?(server_capability_flags, :client_ssl) do
+    if config.ssl_opts && !has_capability_flag?(server_capability_flags, :client_ssl) do
       {:error, :server_does_not_support_ssl}
     else
       client_capability_flags =

lib/myxql/protocol/auth.ex

@@ -39,11 +39,12 @@ defmodule MyXQL.Protocol.Auth do
       auth_plugin_name == "mysql_native_password" ->
         mysql_native_password(config.password, initial_auth_plugin_data)
 
-      auth_plugin_name == "sha256_password" and config.ssl? ->
-        config.password <> <<0>>
-
-      auth_plugin_name == "sha256_password" and not config.ssl? ->
-        <<1>>
+      auth_plugin_name == "sha256_password" ->
+        if config.ssl_opts do
+          config.password <> <<0>>
+        else
+          <<1>>
+        end
 
       auth_plugin_name == "caching_sha2_password" ->
         sha256_password(config.password, initial_auth_plugin_data)

test/myxql/client_test.exs

@@ -4,6 +4,7 @@ defmodule MyXQL.ClientTest do
   import MyXQL.Protocol.{Flags, Records}
 
   @opts TestHelper.opts()
+  @opts_with_ssl TestHelper.opts_with_ssl()
 
   describe "connect" do
     @tag public_key_exchange: true
@@ -15,7 +16,7 @@ defmodule MyXQL.ClientTest do
 
     @tag ssl: true
     test "default auth plugin (ssl)" do
-      opts = [username: "default_auth", password: "secret", ssl: true] ++ @opts
+      opts = [username: "default_auth", password: "secret"] ++ @opts_with_ssl
       assert {:ok, client} = Client.connect(opts)
       Client.com_quit(client)
     end
@@ -47,7 +48,7 @@ defmodule MyXQL.ClientTest do
 
     @tag ssl: true
     test "no password (ssl)" do
-      opts = [username: "nopassword", ssl: true] ++ @opts
+      opts = [username: "nopassword"] ++ @opts_with_ssl
       assert {:ok, client} = Client.connect(opts)
       Client.com_quit(client)
 
@@ -73,7 +74,7 @@ defmodule MyXQL.ClientTest do
 
     @tag mysql_native_password: true, ssl: true
     test "mysql_native_password (ssl)" do
-      opts = [username: "mysql_native", password: "secret", ssl: true] ++ @opts
+      opts = [username: "mysql_native", password: "secret"] ++ @opts_with_ssl
       assert {:ok, client} = Client.connect(opts)
       Client.com_quit(client)
     end
@@ -106,7 +107,7 @@ defmodule MyXQL.ClientTest do
 
     @tag sha256_password: true, ssl: true
     test "sha256_password (ssl)" do
-      opts = [username: "sha256_password", password: "secret", ssl: true] ++ @opts
+      opts = [username: "sha256_password", password: "secret"] ++ @opts_with_ssl
       assert {:ok, client} = Client.connect(opts)
       Client.com_quit(client)
     end
@@ -119,13 +120,13 @@ defmodule MyXQL.ClientTest do
 
     @tag sha256_password: true, ssl: true
     test "sha256_password (bad password) (ssl)" do
-      opts = [username: "sha256_password", password: "bad", ssl: true] ++ @opts
+      opts = [username: "sha256_password", password: "bad"] ++ @opts_with_ssl
       {:error, err_packet(message: "Access denied" <> _)} = Client.connect(opts)
     end
 
     @tag sha256_password: true, ssl: true
     test "sha256_password (empty password) (ssl)" do
-      opts = [username: "sha256_empty", ssl: true] ++ @opts
+      opts = [username: "sha256_empty"] ++ @opts_with_ssl
       assert {:ok, client} = Client.connect(opts)
       Client.com_quit(client)
     end
@@ -156,7 +157,7 @@ defmodule MyXQL.ClientTest do
 
     @tag caching_sha2_password: true, ssl: true
     test "caching_sha2_password (ssl)" do
-      opts = [username: "caching_sha2_password", password: "secret", ssl: true] ++ @opts
+      opts = [username: "caching_sha2_password", password: "secret"] ++ @opts_with_ssl
       assert {:ok, client} = Client.connect(opts)
       Client.com_quit(client)
     end
@@ -169,7 +170,7 @@ defmodule MyXQL.ClientTest do
 
     @tag caching_sha2_password: true, ssl: true
     test "caching_sha2_password (bad password) (ssl)" do
-      opts = [username: "caching_sha2_password", password: "bad", ssl: true] ++ @opts
+      opts = [username: "caching_sha2_password", password: "bad"] ++ @opts_with_ssl
       {:error, err_packet(message: "Access denied" <> _)} = Client.connect(opts)
     end
 
@@ -194,8 +195,7 @@ defmodule MyXQL.ClientTest do
 
     @tag ssl: false
     test "client requires ssl but server does not support it" do
-      opts = [ssl: true] ++ @opts
-      assert {:error, :server_does_not_support_ssl} = Client.connect(opts)
+      assert {:error, :server_does_not_support_ssl} = Client.connect(@opts_with_ssl)
     end
 
     test "default charset" do

test/myxql_test.exs

@@ -3,12 +3,13 @@ defmodule MyXQLTest do
   import ExUnit.CaptureLog
 
   @opts TestHelper.opts()
+  @opts_with_ssl TestHelper.opts_with_ssl()
 
   describe "connect" do
     @tag ssl: true
     test "connect with bad SSL opts" do
       assert capture_log(fn ->
-               opts = [ssl: true, ssl_opts: [ciphers: [:bad]]] ++ @opts
+               opts = put_in(@opts_with_ssl[:ssl][:ciphers], [:bad])
                assert_start_and_killed(opts)
              end) =~
                "** (DBConnection.ConnectionError) (127.0.0.1:3306) Invalid TLS option: {ciphers,[bad]}"
@@ -164,7 +165,9 @@ defmodule MyXQLTest do
 
       test "#{@protocol}: query with multiple rows", c do
         %MyXQL.Result{num_rows: 2} =
-          MyXQL.query!(c.conn, "INSERT INTO integers VALUES (10), (20)", [], query_type: @protocol)
+          MyXQL.query!(c.conn, "INSERT INTO integers VALUES (10), (20)", [],
+            query_type: @protocol
+          )
 
         assert {:ok, %MyXQL.Result{columns: ["x"], rows: [[10], [20]]}} =
                  MyXQL.query(c.conn, "SELECT * FROM integers")
@@ -176,7 +179,9 @@ defmodule MyXQLTest do
         values = Enum.map_join(1..num, ", ", &"(#{&1})")
 
         result =
-          MyXQL.query!(c.conn, "INSERT INTO integers VALUES " <> values, [], query_type: @protocol)
+          MyXQL.query!(c.conn, "INSERT INTO integers VALUES " <> values, [],
+            query_type: @protocol
+          )
 
         assert result.num_rows == num
 
@@ -784,8 +789,9 @@ defmodule MyXQLTest do
     end
   end
 
-  @tag :skip
   describe "idle ping" do
+    @describetag :skip
+
     test "query before and after" do
       opts = [backoff_type: :stop, idle_interval: 1] ++ @opts
       {:ok, pid} = MyXQL.start_link(opts)

test/test_helper.exs

@@ -1,20 +1,25 @@
 defmodule TestHelper do
-  def opts() do
+  def opts do
     [
       hostname: "127.0.0.1",
       username: "root",
       database: "myxql_test",
       timeout: 5000,
-      ssl_opts: ssl_opts(),
       backoff_type: :stop,
       max_restarts: 0,
       pool_size: 1,
       show_sensitive_data_on_connection_error: true
     ]
   end
 
-  defp ssl_opts() do
-    [versions: [:"tlsv1.2"]]
+  def opts_with_ssl do
+    opts() ++
+      [
+        ssl: [
+          verify: :verify_none,
+          versions: [:"tlsv1.2"]
+        ]
+      ]
   end
 
   def setup_server() do