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using Dino.Entities;
using Qlite;
using Gee;
using Signal;
using Xmpp;
namespace Dino.Plugins.Omemo {
public class OmemoDecryptor : Xep.Omemo.OmemoDecryptor {
private Account account;
private Store store;
private Database db;
private StreamInteractor stream_interactor;
private TrustManager trust_manager;
public override uint32 own_device_id { get { return store.local_registration_id; }}
public OmemoDecryptor(Account account, StreamInteractor stream_interactor, TrustManager trust_manager, Database db, Store store) {
this.account = account;
this.stream_interactor = stream_interactor;
this.trust_manager = trust_manager;
this.db = db;
this.store = store;
}
public bool decrypt_message(Entities.Message message, Xmpp.MessageStanza stanza, Conversation conversation) {
StanzaNode? encrypted_node = stanza.stanza.get_subnode("encrypted", NS_URI);
if (encrypted_node == null || MessageFlag.get_flag(stanza) != null || stanza.from == null) return false;
if (message.body == null && Xep.ExplicitEncryption.get_encryption_tag(stanza) == NS_URI) {
message.body = "[This message is OMEMO encrypted]"; // TODO temporary
}
if (!Plugin.ensure_context()) return false;
int identity_id = db.identity.get_id(conversation.account.id);
MessageFlag flag = new MessageFlag();
stanza.add_flag(flag);
Xep.Omemo.ParsedData? data = parse_node(encrypted_node);
if (data == null || data.ciphertext == null) return false;
foreach (Bytes encr_key in data.our_potential_encrypted_keys.keys) {
data.is_prekey = data.our_potential_encrypted_keys[encr_key];
data.encrypted_key = encr_key.get_data();
Gee.List<Jid> possible_jids = get_potential_message_jids(message, data, identity_id);
if (possible_jids.size == 0) {
debug("Received message from unknown entity with device id %d", data.sid);
}
foreach (Jid possible_jid in possible_jids) {
try {
uint8[] key = decrypt_key(data, possible_jid);
string cleartext = arr_to_str(aes_decrypt(Cipher.AES_GCM_NOPADDING, key, data.iv, data.ciphertext));
// If we figured out which real jid a message comes from due to decryption working, save it
if (conversation.type_ == Conversation.Type.GROUPCHAT && message.real_jid == null) {
message.real_jid = possible_jid;
}
message.body = cleartext;
message.encryption = Encryption.OMEMO;
trust_manager.message_device_id_map[message] = data.sid;
return true;
} catch (Error e) {
debug("Decrypting message from %s/%d failed: %s", possible_jid.to_string(), data.sid, e.message);
}
}
}
if (
encrypted_node.get_deep_string_content("payload") != null && // Ratchet forwarding doesn't contain payload and might not include us, which is ok
data.our_potential_encrypted_keys.size == 0 && // The message was not encrypted to us
stream_interactor.module_manager.get_module(message.account, StreamModule.IDENTITY).store.local_registration_id != data.sid // Message from this device. Never encrypted to itself.
) {
db.identity_meta.update_last_message_undecryptable(identity_id, data.sid, message.time);
trust_manager.bad_message_state_updated(conversation.account, message.from, data.sid);
}
debug("Received OMEMO encryped message that could not be decrypted.");
return false;
}
public Gee.List<Jid> get_potential_message_jids(Entities.Message message, Xmpp.Xep.Omemo.ParsedData data, int identity_id) {
Gee.List<Jid> possible_jids = new ArrayList<Jid>();
if (message.type_ == Message.Type.CHAT) {
possible_jids.add(message.from.bare_jid);
} else {
if (message.real_jid != null) {
possible_jids.add(message.real_jid.bare_jid);
} else if (data.is_prekey) {
// pre key messages do store the identity key, so we can use that to find the real jid
PreKeySignalMessage msg = Plugin.get_context().deserialize_pre_key_signal_message(data.encrypted_key);
string identity_key = Base64.encode(msg.identity_key.serialize());
foreach (Row row in db.identity_meta.get_with_device_id(identity_id, data.sid).with(db.identity_meta.identity_key_public_base64, "=", identity_key)) {
try {
possible_jids.add(new Jid(row[db.identity_meta.address_name]));
} catch (InvalidJidError e) {
warning("Ignoring invalid jid from database: %s", e.message);
}
}
} else {
// If we don't know the device name (MUC history w/o MAM), test decryption with all keys with fitting device id
foreach (Row row in db.identity_meta.get_with_device_id(identity_id, data.sid)) {
try {
possible_jids.add(new Jid(row[db.identity_meta.address_name]));
} catch (InvalidJidError e) {
warning("Ignoring invalid jid from database: %s", e.message);
}
}
}
}
return possible_jids;
}
public override uint8[] decrypt_key(Xmpp.Xep.Omemo.ParsedData data, Jid from_jid) throws GLib.Error {
int sid = data.sid;
uint8[] ciphertext = data.ciphertext;
uint8[] encrypted_key = data.encrypted_key;
Address address = new Address(from_jid.to_string(), sid);
uint8[] key;
if (data.is_prekey) {
int identity_id = db.identity.get_id(account.id);
PreKeySignalMessage msg = Plugin.get_context().deserialize_pre_key_signal_message(encrypted_key);
string identity_key = Base64.encode(msg.identity_key.serialize());
bool ok = update_db_for_prekey(identity_id, identity_key, from_jid, sid);
if (!ok) return null;
debug("Starting new session for decryption with device from %s/%d", from_jid.to_string(), sid);
SessionCipher cipher = store.create_session_cipher(address);
key = cipher.decrypt_pre_key_signal_message(msg);
// TODO: Finish session
} else {
debug("Continuing session for decryption with device from %s/%d", from_jid.to_string(), sid);
SignalMessage msg = Plugin.get_context().deserialize_signal_message(encrypted_key);
SessionCipher cipher = store.create_session_cipher(address);
key = cipher.decrypt_signal_message(msg);
}
if (key.length >= 32) {
int authtaglength = key.length - 16;
uint8[] new_ciphertext = new uint8[ciphertext.length + authtaglength];
uint8[] new_key = new uint8[16];
Memory.copy(new_ciphertext, ciphertext, ciphertext.length);
Memory.copy((uint8*)new_ciphertext + ciphertext.length, (uint8*)key + 16, authtaglength);
Memory.copy(new_key, key, 16);
data.ciphertext = new_ciphertext;
key = new_key;
}
return key;
}
public override string decrypt(uint8[] ciphertext, uint8[] key, uint8[] iv) throws GLib.Error {
return arr_to_str(aes_decrypt(Cipher.AES_GCM_NOPADDING, key, iv, ciphertext));
}
private bool update_db_for_prekey(int identity_id, string identity_key, Jid from_jid, int sid) {
Row? device = db.identity_meta.get_device(identity_id, from_jid.to_string(), sid);
if (device != null && device[db.identity_meta.identity_key_public_base64] != null) {
if (device[db.identity_meta.identity_key_public_base64] != identity_key) {
critical("Tried to use a different identity key for a known device id.");
return false;
}
} else {
debug("Learn new device from incoming message from %s/%d", from_jid.to_string(), sid);
bool blind_trust = db.trust.get_blind_trust(identity_id, from_jid.to_string(), true);
if (db.identity_meta.insert_device_session(identity_id, from_jid.to_string(), sid, identity_key, blind_trust ? TrustLevel.TRUSTED : TrustLevel.UNKNOWN) < 0) {
critical("Failed learning a device.");
return false;
}
XmppStream? stream = stream_interactor.get_stream(account);
if (device == null && stream != null) {
stream.get_module(StreamModule.IDENTITY).request_user_devicelist.begin(stream, from_jid);
}
}
return true;
}
private string arr_to_str(uint8[] arr) {
// null-terminate the array
uint8[] rarr = new uint8[arr.length+1];
Memory.copy(rarr, arr, arr.length);
return (string)rarr;
}
}
public class DecryptMessageListener : MessageListener {
public string[] after_actions_const = new string[]{ };
public override string action_group { get { return "DECRYPT"; } }
public override string[] after_actions { get { return after_actions_const; } }
private HashMap<Account, OmemoDecryptor> decryptors;
public DecryptMessageListener(HashMap<Account, OmemoDecryptor> decryptors) {
this.decryptors = decryptors;
}
public override async bool run(Entities.Message message, Xmpp.MessageStanza stanza, Conversation conversation) {
decryptors[message.account].decrypt_message(message, stanza, conversation);
return false;
}
}
}
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