using GPG; using Xmpp.Core; namespace Xmpp.Xep.Pgp { 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 IDENTITY = new ModuleIdentity(NS_URI, ID); public signal void received_jid_key_id(XmppStream stream, string jid, string key_id); private string? signed_status; private string? own_key_id; public Module() { GPG.check_version(); signed_status = gpg_sign(""); if (signed_status != null) own_key_id = gpg_verify(signed_status, ""); } public bool encrypt(Message.Stanza message, string key_id) { string? enc_body = gpg_encrypt(message.body, new string[] {key_id, own_key_id}); 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 = gpg_verify(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? gpg_verify(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) { string signed; try { signed = GPGHelper.sign(str, GPG.SigMode.CLEAR); } 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; } } }