[gnome-remote-desktop] credentials: Add TPM 2.0 backend

[Jonas Ådahl <jadahl src gnome org>]

commit a8840eb1a66ca86f00e1e15be3bc96c6f33ea52b
Author: Jonas Ådahl <jadahl gmail com>
Date:   Tue Jun 21 16:15:00 2022 +0200

    credentials: Add TPM 2.0 backend
    
    This uses the TPM 2.0 module for encrypting/decrypting credentials; this
    will be used on headless sessions where libsecret isn't available.

 src/grd-credentials-tpm.c | 234 ++++++++++++++++++++++++++++++++++++++++++++++
 src/grd-credentials-tpm.h |  32 +++++++
 src/meson.build           |   8 ++
 tests/meson.build         |   4 -
 4 files changed, 274 insertions(+), 4 deletions(-)
---
diff --git a/src/grd-credentials-tpm.c b/src/grd-credentials-tpm.c
new file mode 100644
index 00000000..86bc055c
--- /dev/null
+++ b/src/grd-credentials-tpm.c
@@ -0,0 +1,234 @@
+/*
+ * Copyright (C) 2022 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ *
+ */
+
+#include "config.h"
+
+#include "grd-credentials-tpm.h"
+
+#include <gio/gio.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "grd-tpm.h"
+
+struct _GrdCredentialsTpm
+{
+  GrdCredentials parent;
+};
+
+G_DEFINE_TYPE (GrdCredentialsTpm, grd_credentials_tpm, GRD_TYPE_CREDENTIALS)
+
+static const char *
+secret_file_name_from_type (GrdCredentialsType type)
+{
+  switch (type)
+    {
+    case GRD_CREDENTIALS_TYPE_RDP:
+      return "rdp-credentials.priv";
+    case GRD_CREDENTIALS_TYPE_VNC:
+      return "vnc-credentials.priv";
+    }
+
+  g_assert_not_reached ();
+}
+
+static gboolean
+grd_credentials_tpm_store (GrdCredentials      *credentials,
+                           GrdCredentialsType   type,
+                           GVariant            *variant,
+                           GError             **error)
+{
+  g_autoptr (GrdTpm) tpm = NULL;
+  g_autofree const char *serialized = NULL;
+  ESYS_TR primary_handle = 0;
+  g_autofree TPMS_CONTEXT *primary = NULL;
+  g_autofree TPML_PCR_SELECTION *pcr_selection = NULL;
+  g_autofree TPML_DIGEST *pcr_digest = NULL;
+  g_autofree TPMS_CONTEXT *secret_tpms_context = NULL;
+  g_autoptr (GVariant) secret_variant = NULL;
+  g_autofree char *secret_serialized = NULL;
+  g_autofree char *dir_path = NULL;
+  g_autoptr (GFile) dir = NULL;
+  const char *secret_file_name;
+  g_autofree char *secret_path = NULL;
+  g_autoptr (GFile) secret_file = NULL;
+
+  g_variant_ref_sink (variant);
+  serialized = g_variant_print (variant, TRUE);
+  g_variant_unref (variant);
+
+  tpm = grd_tpm_new (GRD_TPM_MODE_WRITE, error);
+  if (!tpm)
+    return FALSE;
+
+  if (!grd_tpm_create_primary (tpm, &primary_handle, error))
+    return FALSE;
+
+  if (!grd_tpm_read_pcr (tpm, &pcr_selection, &pcr_digest, error))
+    return FALSE;
+
+  if (!grd_tpm_store_secret (tpm,
+                             serialized,
+                             primary_handle,
+                             pcr_selection,
+                             pcr_digest,
+                             &secret_tpms_context,
+                             error))
+    return FALSE;
+
+  secret_variant = grd_tpms_context_to_variant (secret_tpms_context);
+
+  dir_path = g_build_path ("/",
+                           g_get_user_data_dir (),
+                           "gnome-remote-desktop",
+                           NULL);
+  dir = g_file_new_for_path (dir_path);
+  if (!g_file_query_exists (dir, NULL))
+    {
+      if (!g_file_make_directory_with_parents (dir, NULL, error))
+        return FALSE;
+    }
+
+  secret_file_name = secret_file_name_from_type (type);
+  secret_path = g_build_path ("/", dir_path, secret_file_name, NULL);
+  secret_file = g_file_new_for_path (secret_path);
+
+  secret_serialized = g_variant_print (secret_variant, TRUE);
+
+  return g_file_replace_contents (secret_file,
+                                  secret_serialized,
+                                  strlen (secret_serialized) + 1,
+                                  NULL, FALSE,
+                                  G_FILE_CREATE_PRIVATE |
+                                  G_FILE_CREATE_REPLACE_DESTINATION,
+                                  NULL, NULL, error);
+}
+
+static GVariant *
+grd_credentials_tpm_lookup (GrdCredentials      *credentials,
+                            GrdCredentialsType   type,
+                            GError             **error)
+{
+  g_autoptr (GrdTpm) tpm = NULL;
+  const char *secret_file_name;
+  g_autofree char *secret_path = NULL;
+  g_autofree char *serialized = NULL;
+  g_autofree TPML_PCR_SELECTION *pcr_selection = NULL;
+  g_autofree TPML_DIGEST *pcr_digest = NULL;
+  g_autoptr (GVariant) secret_variant = NULL;
+  g_autoptr (GError) local_error = NULL;
+  g_autofree char *credentials_string = NULL;
+
+  secret_file_name = secret_file_name_from_type (type);
+  secret_path = g_build_path ("/",
+                              g_get_user_data_dir (),
+                              "gnome-remote-desktop",
+                              secret_file_name,
+                              NULL);
+
+  if (!g_file_get_contents (secret_path,
+                            &serialized,
+                            NULL,
+                            &local_error))
+    {
+      if (g_error_matches (local_error, G_FILE_ERROR, G_FILE_ERROR_NOENT))
+        return NULL;
+
+      g_propagate_error (error, g_steal_pointer (&local_error));
+      return NULL;
+    }
+
+  secret_variant = g_variant_parse (G_VARIANT_TYPE ("(uutqs)"), serialized,
+                                    NULL, NULL, error);
+  if (!secret_variant)
+    return NULL;
+
+  tpm = grd_tpm_new (GRD_TPM_MODE_READ, error);
+  if (!tpm)
+    return FALSE;
+
+  if (!grd_tpm_read_pcr (tpm, &pcr_selection, &pcr_digest, error))
+    return NULL;
+
+  credentials_string = grd_tpm_restore_secret (tpm,
+                                               secret_variant,
+                                               pcr_selection,
+                                               pcr_digest,
+                                               error);
+  if (!credentials_string)
+    return NULL;
+
+  return g_variant_parse (NULL, credentials_string, NULL, NULL, error);
+}
+
+static gboolean
+grd_credentials_tpm_clear (GrdCredentials      *credentials,
+                           GrdCredentialsType   type,
+                           GError             **error)
+{
+  const char *secret_file_name;
+  g_autofree char *secret_path = NULL;
+  g_autoptr (GFile) secret_file = NULL;
+  g_autoptr (GError) local_error = NULL;
+
+  secret_file_name = secret_file_name_from_type (type);
+  secret_path = g_build_path ("/",
+                              g_get_user_data_dir (),
+                              "gnome-remote-desktop",
+                              secret_file_name,
+                              NULL);
+  secret_file = g_file_new_for_path (secret_path);
+
+  if (!g_file_delete (secret_file, NULL, error))
+    {
+      if (g_error_matches (local_error, G_IO_ERROR, G_IO_ERROR_NOT_FOUND))
+        {
+          return TRUE;
+        }
+      else
+        {
+          g_propagate_error (error, local_error);
+          return FALSE;
+        }
+    }
+
+  return TRUE;
+}
+
+GrdCredentialsTpm *
+grd_credentials_tpm_new (GError **error)
+{
+  return g_object_new (GRD_TYPE_CREDENTIALS_TPM, NULL);
+}
+
+static void
+grd_credentials_tpm_init (GrdCredentialsTpm *credentials_tpm)
+{
+}
+
+static void
+grd_credentials_tpm_class_init (GrdCredentialsTpmClass *klass)
+{
+  GrdCredentialsClass *credentials_class = GRD_CREDENTIALS_CLASS (klass);
+
+  credentials_class->store = grd_credentials_tpm_store;
+  credentials_class->lookup = grd_credentials_tpm_lookup;
+  credentials_class->clear = grd_credentials_tpm_clear;
+}
diff --git a/src/grd-credentials-tpm.h b/src/grd-credentials-tpm.h
new file mode 100644
index 00000000..1e26fb8a
--- /dev/null
+++ b/src/grd-credentials-tpm.h
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2022 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ *
+ */
+
+#ifndef GRD_CREDENTIALS_TPM_H
+#define GRD_CREDENTIALS_TPM_H
+
+#include "grd-credentials.h"
+
+#define GRD_TYPE_CREDENTIALS_TPM (grd_credentials_tpm_get_type ())
+G_DECLARE_FINAL_TYPE (GrdCredentialsTpm, grd_credentials_tpm,
+                      GRD, CREDENTIALS_TPM, GrdCredentials)
+
+GrdCredentialsTpm * grd_credentials_tpm_new (GError **error);
+
+#endif /* GRD_CREDENTIALS_TPM_H */
diff --git a/src/meson.build b/src/meson.build
index 33c324fc..54c418ef 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -2,6 +2,10 @@ src_includepath = include_directories('.')
 
 credentials_deps = [
   libsecret_dep,
+  tss2_esys_dep,
+  tss2_mu_dep,
+  tss2_rc_dep,
+  tss2_tctildr_dep,
 ]
 
 deps = [
@@ -22,6 +26,10 @@ credentials_sources = files([
   'grd-credentials.h',
   'grd-credentials-libsecret.c',
   'grd-credentials-libsecret.h',
+  'grd-credentials-tpm.c',
+  'grd-credentials-tpm.h',
+  'grd-tpm.c',
+  'grd-tpm.h',
 ])
 
 daemon_sources = files([
diff --git a/tests/meson.build b/tests/meson.build
index 3fc21358..31247291 100644
--- a/tests/meson.build
+++ b/tests/meson.build
@@ -77,10 +77,6 @@ tpm_test = executable(
   ],
   dependencies: [
     deps,
-    tss2_esys_dep,
-    tss2_mu_dep,
-    tss2_rc_dep,
-    tss2_tctildr_dep,
   ],
   include_directories: [
     src_includepath,