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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<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;
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);
Presence.Module.get_module(stream).received_presence.connect(on_received_presence);
Presence.Module.get_module(stream).pre_send_presence_stanza.connect(on_pre_send_presence_stanza);
Message.Module.require(stream);
Message.Module.get_module(stream).pre_received_message.connect(on_pre_received_message);
stream.add_flag(new Flag());
}
public override void detach(XmppStream stream) {
Presence.Module.get_module(stream).received_presence.disconnect(on_received_presence);
Presence.Module.get_module(stream).pre_send_presence_stanza.disconnect(on_pre_send_presence_stanza);
Message.Module.get_module(stream).pre_received_message.disconnect(on_pre_received_message);
}
public static Module? get_module(XmppStream stream) {
return (Module?) stream.get_module(IDENTITY);
}
public static void require(XmppStream stream) {
if (get_module(stream) == 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; }
}
}
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