feat(linux): adding pam support

linux/CMakeLists.txt

@@ -1,6 +1,6 @@
 # Project-level configuration.
 cmake_minimum_required(VERSION 3.10)
-project(runner LANGUAGES CXX)
+project(runner LANGUAGES CXX C)
 
 # The name of the executable created for the application. Change this to change
 # the on-disk name of your application.
@@ -64,6 +64,7 @@ add_definitions(-DAPPLICATION_ID="${APPLICATION_ID}")
 add_executable(${BINARY_NAME}
   "main.cc"
   "application.cc"
+  "channels/auth.cc"
   "channels/outputs.cc"
   "${FLUTTER_MANAGED_DIR}/generated_plugin_registrant.cc"
 )
@@ -74,7 +75,7 @@ apply_standard_settings(${BINARY_NAME})
 
 # Add dependency libraries. Add any application-specific dependencies here.
 target_link_libraries(${BINARY_NAME} PRIVATE flutter)
-target_link_libraries(${BINARY_NAME} PRIVATE PkgConfig::GTK)
+target_link_libraries(${BINARY_NAME} PRIVATE PkgConfig::GTK PkgConfig::PAM)
 
 # Run the Flutter tool portions of the build. This must not be removed.
 add_dependencies(${BINARY_NAME} flutter_assemble)

linux/application-priv.h

@@ -4,5 +4,6 @@ struct _GenesisShellApplication {
   GtkApplication parent_instance;
   char** dart_entrypoint_arguments;
   FlMethodChannel* outputs;
+  FlMethodChannel* auth;
   GtkWindow* win;
 };

linux/application.cc

@@ -2,6 +2,7 @@
 
 #include "application.h"
 #include "application-priv.h"
+#include "channels/auth.h"
 #include "channels/outputs.h"
 
 #include <flutter_linux/flutter_linux.h>
@@ -32,9 +33,17 @@ static void genesis_shell_application_activate(GApplication* application) {
 
   fl_register_plugins(FL_PLUGIN_REGISTRY(view));
 
-  g_autoptr(FlStandardMethodCodec) codec = fl_standard_method_codec_new();
-  self->outputs = fl_method_channel_new(fl_engine_get_binary_messenger(fl_view_get_engine(view)), "com.expidusos.genesis.shell/outputs", FL_METHOD_CODEC(codec));
-  fl_method_channel_set_method_call_handler(self->outputs, outputs_method_call_handler, self, nullptr);
+  {
+    g_autoptr(FlStandardMethodCodec) codec = fl_standard_method_codec_new();
+    self->outputs = fl_method_channel_new(fl_engine_get_binary_messenger(fl_view_get_engine(view)), "com.expidusos.genesis.shell/outputs", FL_METHOD_CODEC(codec));
+    fl_method_channel_set_method_call_handler(self->outputs, outputs_method_call_handler, self, nullptr);
+  }
+
+  {
+    g_autoptr(FlStandardMethodCodec) codec = fl_standard_method_codec_new();
+    self->auth = fl_method_channel_new(fl_engine_get_binary_messenger(fl_view_get_engine(view)), "com.expidusos.genesis.shell/auth", FL_METHOD_CODEC(codec));
+    fl_method_channel_set_method_call_handler(self->auth, auth_method_call_handler, self, nullptr);
+  }
 
   gtk_widget_grab_focus(GTK_WIDGET(view));
 }
@@ -81,6 +90,7 @@ static void genesis_shell_application_dispose(GObject* object) {
   GenesisShellApplication* self = GENESIS_SHELL_APPLICATION(object);
   g_clear_pointer(&self->dart_entrypoint_arguments, g_strfreev);
   g_clear_object(&self->outputs);
+  g_clear_object(&self->auth);
   G_OBJECT_CLASS(genesis_shell_application_parent_class)->dispose(object);
 }
 

linux/channels/auth.cc

@@ -0,0 +1,94 @@
+#include <flutter_linux/flutter_linux.h>
+
+#include <security/pam_appl.h>
+#include <security/pam_misc.h>
+
+#include "outputs.h"
+#include "../application-priv.h"
+
+static void message_callback(GObject* obj, GAsyncResult* result, gpointer user_data) {
+  GArray* array_resp = (GArray*)user_data;
+
+  g_autoptr(FlMethodResponse) response = fl_method_channel_invoke_method_finish(FL_METHOD_CHANNEL(obj), result, nullptr);
+  g_autoptr(FlValue) resp_value = fl_method_response_get_result(response, nullptr);
+
+  struct pam_response resp;
+  resp.resp_retcode = 0;
+  resp.resp = g_strdup(fl_value_get_string(resp_value));
+  g_array_append_val(array_resp, resp);
+}
+
+static int conversation(int num_msg, const struct pam_message** msg, struct pam_response** resp, void* appdata_ptr) {
+  GenesisShellApplication* self = GENESIS_SHELL_APPLICATION(appdata_ptr);
+
+  GArray* array_resp = g_array_new(false, true, sizeof (struct pam_response));
+
+  for (int i = 0; i < num_msg; i++) {
+		const char* msg_content = msg[i]->msg;
+
+    fl_method_channel_invoke_method(self->auth, "ask", fl_value_new_string(msg_content), nullptr, message_callback, array_resp);
+  }
+
+  while (true) {
+    if ((array_resp->len / sizeof (struct pam_response)) == num_msg) {
+      break;
+    }
+  }
+
+  *resp = static_cast<struct pam_response*>(g_array_steal(array_resp, nullptr));
+  return PAM_SUCCESS;
+}
+
+void auth_method_call_handler(FlMethodChannel* channel, FlMethodCall* method_call, gpointer user_data) {
+  g_autoptr(FlMethodResponse) response = nullptr;
+  if (strcmp(fl_method_call_get_name(method_call), "start") == 0) {
+    FlValue* args = fl_method_call_get_args(method_call);
+
+    gchar* username = nullptr;
+    if (fl_value_lookup_string(args, "username") != nullptr) {
+      username = (gchar*)fl_value_get_string(fl_value_lookup_string(args, "username"));
+    }
+
+    struct pam_conv* conv = (struct pam_conv*)malloc(sizeof(struct pam_conv));
+    conv->conv = conversation;
+    conv->appdata_ptr = user_data;
+
+    pam_handle_t* handle = NULL;
+    int r = pam_start("genesis-shell", username, conv, &handle);
+    if (r != PAM_SUCCESS) {
+      fl_method_call_respond_error(method_call, "PAM", "pam_start failed", fl_value_new_string(pam_strerror(handle, r)), NULL);
+      pam_end(handle, r);
+      free(conv);
+      return;
+    }
+
+    r = pam_authenticate(handle, PAM_SILENT);
+    if (r != PAM_SUCCESS) {
+      fl_method_call_respond_error(method_call, "PAM", "pam_authenticate failed", fl_value_new_string(pam_strerror(handle, r)), NULL);
+      pam_end(handle, r);
+      free(conv);
+      return;
+    }
+
+    r = pam_acct_mgmt(handle, PAM_SILENT);
+    if (r != PAM_SUCCESS) {
+      fl_method_call_respond_error(method_call, "PAM", "pam_acct_mgmt failed", fl_value_new_string(pam_strerror(handle, r)), NULL);
+      pam_end(handle, r);
+      free(conv);
+      return;
+    }
+
+    pam_get_item(handle, PAM_USER, (const void**)&username);
+    pam_end(handle, r);
+    free(conv);
+
+    response = FL_METHOD_RESPONSE(fl_method_success_response_new(fl_value_new_string(username)));
+  } else {
+    response = FL_METHOD_RESPONSE(fl_method_not_implemented_response_new());
+  }
+
+  g_autoptr(GError) error = nullptr;
+  if (!fl_method_call_respond(method_call, response, &error)) {
+    g_warning("Failed to send response: %s", error->message);
+  }
+}

linux/channels/auth.h

@@ -0,0 +1,7 @@
+#pragma once
+
+#include <flutter_linux/flutter_linux.h>
+
+#include "../application.h"
+
+void auth_method_call_handler(FlMethodChannel* channel, FlMethodCall* method_call, gpointer user_data);