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Diffstat (limited to 'plugins/omemo/src/logic/encrypt.vala')
| -rw-r--r-- | plugins/omemo/src/logic/encrypt.vala | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/plugins/omemo/src/logic/encrypt.vala b/plugins/omemo/src/logic/encrypt.vala new file mode 100644 index 00000000..cd994c3a --- /dev/null +++ b/plugins/omemo/src/logic/encrypt.vala @@ -0,0 +1,131 @@ +using Gee; +using Signal; +using Dino.Entities; +using Xmpp; +using Xmpp.Xep.Omemo; + +namespace Dino.Plugins.Omemo { + + public class OmemoEncryptor : Xep.Omemo.OmemoEncryptor { + + private Account account; + private Store store; + private TrustManager trust_manager; + + public override uint32 own_device_id { get { return store.local_registration_id; }} + + public OmemoEncryptor(Account account, TrustManager trust_manager, Store store) { + this.account = account; + this.trust_manager = trust_manager; + this.store = store; + } + + public override Xep.Omemo.EncryptionData encrypt_plaintext(string plaintext) throws GLib.Error { + const uint KEY_SIZE = 16; + const uint IV_SIZE = 12; + + //Create a key and use it to encrypt the message + uint8[] key = new uint8[KEY_SIZE]; + Plugin.get_context().randomize(key); + uint8[] iv = new uint8[IV_SIZE]; + Plugin.get_context().randomize(iv); + + uint8[] aes_encrypt_result = aes_encrypt(Cipher.AES_GCM_NOPADDING, key, iv, plaintext.data); + uint8[] ciphertext = aes_encrypt_result[0:aes_encrypt_result.length - 16]; + uint8[] tag = aes_encrypt_result[aes_encrypt_result.length - 16:aes_encrypt_result.length]; + uint8[] keytag = new uint8[key.length + tag.length]; + Memory.copy(keytag, key, key.length); + Memory.copy((uint8*)keytag + key.length, tag, tag.length); + + var ret = new Xep.Omemo.EncryptionData(own_device_id); + ret.ciphertext = ciphertext; + ret.keytag = keytag; + ret.iv = iv; + return ret; + } + + public EncryptState encrypt(MessageStanza message, Jid self_jid, Gee.List<Jid> recipients, XmppStream stream) { + + EncryptState status = new EncryptState(); + if (!Plugin.ensure_context()) return status; + if (message.to == null) return status; + + try { + EncryptionData enc_data = encrypt_plaintext(message.body); + status = encrypt_key_to_recipients(enc_data, self_jid, recipients, stream); + + message.stanza.put_node(enc_data.get_encrypted_node()); + Xep.ExplicitEncryption.add_encryption_tag_to_message(message, NS_URI, "OMEMO"); + message.body = "[This message is OMEMO encrypted]"; + status.encrypted = true; + } catch (Error e) { + warning(@"Signal error while encrypting message: $(e.message)\n"); + message.body = "[OMEMO encryption failed]"; + status.encrypted = false; + } + return status; + } + + internal EncryptState encrypt_key_to_recipients(EncryptionData enc_data, Jid self_jid, Gee.List<Jid> recipients, XmppStream stream) throws Error { + EncryptState status = new EncryptState(); + + //Check we have the bundles and device lists needed to send the message + if (!trust_manager.is_known_address(account, self_jid)) return status; + status.own_list = true; + status.own_devices = trust_manager.get_trusted_devices(account, self_jid).size; + status.other_waiting_lists = 0; + status.other_devices = 0; + foreach (Jid recipient in recipients) { + if (!trust_manager.is_known_address(account, recipient)) { + status.other_waiting_lists++; + } + if (status.other_waiting_lists > 0) return status; + status.other_devices += trust_manager.get_trusted_devices(account, recipient).size; + } + if (status.own_devices == 0 || status.other_devices == 0) return status; + + + //Encrypt the key for each recipient's device individually + foreach (Jid recipient in recipients) { + EncryptionResult enc_res = encrypt_key_to_recipient(stream, enc_data, recipient); + status.add_result(enc_res, false); + } + + // Encrypt the key for each own device + EncryptionResult enc_res = encrypt_key_to_recipient(stream, enc_data, self_jid); + status.add_result(enc_res, true); + + return status; + } + + public override EncryptionResult encrypt_key_to_recipient(XmppStream stream, Xep.Omemo.EncryptionData enc_data, Jid recipient) throws GLib.Error { + var result = new EncryptionResult(); + StreamModule module = stream.get_module(StreamModule.IDENTITY); + + foreach(int32 device_id in trust_manager.get_trusted_devices(account, recipient)) { + if (module.is_ignored_device(recipient, device_id)) { + result.lost++; + continue; + } + try { + encrypt_key(enc_data, recipient, device_id); + result.success++; + } catch (Error e) { + if (e.code == ErrorCode.UNKNOWN) result.unknown++; + else result.failure++; + } + } + return result; + } + + public override void encrypt_key(Xep.Omemo.EncryptionData encryption_data, Jid jid, int32 device_id) throws GLib.Error { + Address address = new Address(jid.to_string(), device_id); + SessionCipher cipher = store.create_session_cipher(address); + CiphertextMessage device_key = cipher.encrypt(encryption_data.keytag); + address.device_id = 0; + debug("Created encrypted key for %s/%d", jid.to_string(), device_id); + + encryption_data.add_device_key(device_id, device_key.serialized, device_key.type == CiphertextType.PREKEY); + } + } +}
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