PGP module: store data in own db, use pgp key as specified in account settings

1 files changed, 166 insertions, 0 deletions

diff --git a/plugins/openpgp/src/stream_module.vala b/plugins/openpgp/src/stream_module.vala
new file mode 100644
index 00000000..6de97066
--- /dev/null
+++ b/plugins/openpgp/src/stream_module.vala
@@ -0,0 +1,166 @@
+using GPG;
+
+using Xmpp;
+using Xmpp.Core;
+
+namespace Dino.Plugins.OpenPgp {
+    private const string NS_URI = "jabber:x";
+    private const string NS_URI_ENCRYPTED = NS_URI + ":encrypted";
+    private const string NS_URI_SIGNED = NS_URI +  ":signed";
+
+    public class Module : XmppStreamModule {
+        public const string ID = "0027_current_pgp_usage";
+        public static ModuleIdentity<Module> IDENTITY = new ModuleIdentity<Module>(NS_URI, ID);
+
+        public signal void received_jid_key_id(XmppStream stream, string jid, string key_id);
+
+        private string? signed_status = null;
+        private Key? own_key = null;
+
+        public Module(string? own_key_id = null) {
+            set_private_key_id(own_key_id);
+        }
+
+        public void set_private_key_id(string? own_key_id) {
+            if (own_key_id != null) {
+                try {
+                    own_key = GPGHelper.get_private_key(own_key_id);
+                    if (own_key == null) print("PRIV KEY NULL\n");
+                } catch (Error e) { }
+                if (own_key != null) {
+                    signed_status = gpg_sign("", own_key);
+                    get_sign_key(signed_status, "");
+                }
+            }
+        }
+
+        public bool encrypt(Message.Stanza message, string key_id) {
+            string? enc_body = gpg_encrypt(message.body, new string[] {key_id, own_key.fpr});
+            if (enc_body != null) {
+                message.stanza.put_node(new StanzaNode.build("x", NS_URI_ENCRYPTED).add_self_xmlns().put_node(new StanzaNode.text(enc_body)));
+                message.body = "[This message is OpenPGP encrypted (see XEP-0027)]";
+                return true;
+            }
+            return false;
+        }
+
+        public string? get_cyphertext(Message.Stanza message) {
+            StanzaNode? x_node = message.stanza.get_subnode("x", NS_URI_ENCRYPTED);
+            return x_node == null ? null : x_node.get_string_content();
+        }
+
+        public override void attach(XmppStream stream) {
+            Presence.Module.require(stream);
+            stream.get_module(Presence.Module.IDENTITY).received_presence.connect(on_received_presence);
+            stream.get_module(Presence.Module.IDENTITY).pre_send_presence_stanza.connect(on_pre_send_presence_stanza);
+            Message.Module.require(stream);
+            stream.get_module(Message.Module.IDENTITY).pre_received_message.connect(on_pre_received_message);
+            stream.add_flag(new Flag());
+        }
+
+        public override void detach(XmppStream stream) {
+            stream.get_module(Presence.Module.IDENTITY).received_presence.disconnect(on_received_presence);
+            stream.get_module(Presence.Module.IDENTITY).pre_send_presence_stanza.disconnect(on_pre_send_presence_stanza);
+            stream.get_module(Message.Module.IDENTITY).pre_received_message.disconnect(on_pre_received_message);
+        }
+
+        public static void require(XmppStream stream) {
+            if (stream.get_module(IDENTITY) == null) stream.add_module(new Module());
+        }
+
+        public override string get_ns() { return NS_URI; }
+        public override string get_id() { return ID; }
+
+        private void on_received_presence(XmppStream stream, Presence.Stanza presence) {
+            StanzaNode x_node = presence.stanza.get_subnode("x", NS_URI_SIGNED);
+            if (x_node != null) {
+                string? sig = x_node.get_string_content();
+                if (sig != null) {
+                    string signed_data = presence.status == null ? "" : presence.status;
+                    string? key_id = get_sign_key(sig, signed_data);
+                    if (key_id != null) {
+                        Flag.get_flag(stream).set_key_id(presence.from, key_id);
+                        received_jid_key_id(stream, presence.from, key_id);
+                    }
+                }
+            }
+        }
+
+        private void on_pre_send_presence_stanza(XmppStream stream, Presence.Stanza presence) {
+            if (presence.type_ == Presence.Stanza.TYPE_AVAILABLE && signed_status != null) {
+                presence.stanza.put_node(new StanzaNode.build("x", NS_URI_SIGNED).add_self_xmlns().put_node(new StanzaNode.text(signed_status)));
+            }
+        }
+
+        private void on_pre_received_message(XmppStream stream, Message.Stanza message) {
+            string? encrypted = get_cyphertext(message);
+            if (encrypted != null) {
+                MessageFlag flag = new MessageFlag();
+                message.add_flag(flag);
+                string? decrypted = gpg_decrypt(encrypted);
+                if (decrypted != null) {
+                    flag.decrypted = true;
+                    message.body = decrypted;
+                }
+            }
+        }
+
+        private static string? gpg_encrypt(string plain, string[] key_ids) {
+            GPG.Key[] keys = new GPG.Key[key_ids.length];
+            string encr;
+            try {
+                for (int i = 0; i < key_ids.length; i++) {
+                    keys[i] = GPGHelper.get_public_key(key_ids[i]);
+                }
+                encr = GPGHelper.encrypt_armor(plain, keys, GPG.EncryptFlags.ALWAYS_TRUST);
+            } catch (Error e) {
+                return null;
+            }
+            int encryption_start = encr.index_of("\n\n") + 2;
+            return encr.substring(encryption_start, encr.length - "\n-----END PGP MESSAGE-----".length - encryption_start);
+        }
+
+        private static string? gpg_decrypt(string enc) {
+            string armor = "-----BEGIN PGP MESSAGE-----\n\n" + enc + "\n-----END PGP MESSAGE-----";
+            string? decr = null;
+            try {
+                decr = GPGHelper.decrypt(armor);
+            } catch (Error e) { }
+            return decr;
+        }
+
+        private static string? get_sign_key(string sig, string signed_text) {
+            string armor = "-----BEGIN PGP MESSAGE-----\n\n" + sig + "\n-----END PGP MESSAGE-----";
+            string? sign_key = null;
+            try {
+                sign_key = GPGHelper.get_sign_key(armor, signed_text);
+            } catch (Error e) { }
+            return sign_key;
+        }
+
+        private static string? gpg_sign(string str, Key key) {
+            string signed;
+            try {
+                signed = GPGHelper.sign(str, GPG.SigMode.CLEAR, key);
+            } catch (Error e) {
+                return null;
+            }
+            int signature_start = signed.index_of("-----BEGIN PGP SIGNATURE-----");
+            signature_start = signed.index_of("\n\n", signature_start) + 2;
+            return signed.substring(signature_start, signed.length - "\n-----END PGP SIGNATURE-----".length - signature_start);
+        }
+    }
+
+    public class MessageFlag : Message.MessageFlag {
+        public const string id = "pgp";
+
+        public bool decrypted = false;
+
+        public static MessageFlag? get_flag(Message.Stanza message) {
+            return (MessageFlag) message.get_flag(NS_URI, id);
+        }
+
+        public override string get_ns() { return NS_URI; }
+        public override string get_id() { return id; }
+    }
+}