[gnome-autoar/wip/oholy/compressor-encryption: 1/2] compressor: Add encryption support

[Ondrej Holy <oholy src gnome org>]

commit 62e5aa4b847a7323afd195a0376a971a1d90545d
Author: Ondrej Holy <oholy redhat com>
Date:   Wed Jun 2 09:57:58 2021 +0200

    compressor: Add encryption support
    
    `AutoarExtractor` supports extraction of encrypted archives. It would be nice
    to have support for encrypted archives also in `AutoarCompressor`. Though the
    libarchive library doesn't provide a much. It supports encryption only for the
    ZIP format. There is a choice between `zipcrypt`, `aes128` and `aes256`. Given
    the phact that `zipcrypt` is insecure and not recommended, I think it is fine
    to hardcode `aes256`. It is probably a bit slower then `aes128`, but more secure.
    So the only thing which needs to be set is a passphrase. Let's add
    `autoar_compressor_set_passphrase` to allow creating encrypted archives.
    
    Relates: https://gitlab.gnome.org/GNOME/nautilus/-/issues/822

 gnome-autoar/autoar-compressor.c | 36 ++++++++++++++++++++++++++++++++++++
 gnome-autoar/autoar-compressor.h |  2 ++
 2 files changed, 38 insertions(+)
---
diff --git a/gnome-autoar/autoar-compressor.c b/gnome-autoar/autoar-compressor.c
index 31a5a58..5da7258 100644
--- a/gnome-autoar/autoar-compressor.c
+++ b/gnome-autoar/autoar-compressor.c
@@ -113,6 +113,8 @@ struct _AutoarCompressor
 
   int in_thread        : 1;
   gboolean create_top_level_directory;
+
+  gchar *passphrase;
 };
 
 G_DEFINE_TYPE (AutoarCompressor, autoar_compressor, G_TYPE_OBJECT)
@@ -455,6 +457,23 @@ autoar_compressor_set_notify_interval (AutoarCompressor *self,
   self->notify_interval = notify_interval;
 }
 
+/**
+ * autoar_compressor_set_passphrase:
+ * @self: an #AutoarCompressor
+ * @passphrase: the archive passphrase
+ *
+ * Sets the archive passphrase. It works only with %ARCHIVE_FORMAT_ZIP.
+ **/
+void
+autoar_compressor_set_passphrase (AutoarCompressor *self,
+                                  const gchar      *passphrase)
+{
+  g_return_if_fail (AUTOAR_IS_COMPRESSOR (self));
+  g_return_if_fail (self->format == AUTOAR_FORMAT_ZIP);
+
+  self->passphrase = g_strdup (passphrase);
+}
+
 static void
 autoar_compressor_dispose (GObject *object)
 {
@@ -536,6 +555,8 @@ autoar_compressor_finalize (GObject *object)
   g_free (self->extension);
   self->extension = NULL;
 
+  g_clear_pointer (&self->passphrase, g_free);
+
   G_OBJECT_CLASS (autoar_compressor_parent_class)->finalize (object);
 }
 
@@ -1292,6 +1313,7 @@ autoar_compressor_init (AutoarCompressor *self)
   self->extension = NULL;
 
   self->in_thread = FALSE;
+  self->passphrase = NULL;
 }
 
 /**
@@ -1373,6 +1395,20 @@ autoar_compressor_step_initialize_object (AutoarCompressor *self)
     self->error = autoar_common_g_error_new_a (self->a, NULL);
     return;
   }
+
+  if (self->passphrase != NULL && self->format == AUTOAR_FORMAT_ZIP) {
+    r = archive_write_set_options (self->a, "zip:encryption=aes256");
+    if (r != ARCHIVE_OK) {
+      self->error = autoar_common_g_error_new_a (self->a, NULL);
+      return;
+    }
+
+    r = archive_write_set_passphrase (self->a, self->passphrase);
+    if (r != ARCHIVE_OK) {
+      self->error = autoar_common_g_error_new_a (self->a, NULL);
+      return;
+    }
+  }
 }
 
 static void
diff --git a/gnome-autoar/autoar-compressor.h b/gnome-autoar/autoar-compressor.h
index 931a4fc..6dad196 100644
--- a/gnome-autoar/autoar-compressor.h
+++ b/gnome-autoar/autoar-compressor.h
@@ -75,6 +75,8 @@ void               autoar_compressor_set_output_is_dest             (AutoarCompr
                                                                      gboolean          output_is_dest);
 void               autoar_compressor_set_notify_interval            (AutoarCompressor *self,
                                                                      gint64            notify_interval);
+void               autoar_compressor_set_passphrase                 (AutoarCompressor *self,
+                                                                     const gchar      *passphrase);
 G_END_DECLS
 
 #endif /* AUTOAR_COMPRESSOR_H */