Send OMEMO-encrypted messages and files using 12 byte IV

This commit is contained in:
Marvin W 2020-09-14 21:56:58 +02:00
parent f6943a4c82
commit cd5b639a82
No known key found for this signature in database
GPG Key ID: 072E9235DB996F2A
6 changed files with 19 additions and 21 deletions

View File

@ -52,14 +52,8 @@ public class OmemoFileDecryptor : FileDecryptor, Object {
MatchInfo match_info;
this.url_regex.match(omemo_http_receive_data.original_url, 0, out match_info);
uint8[] iv_and_key = hex_to_bin(match_info.fetch(2).up());
uint8[] iv, key;
if (iv_and_key.length == 44) {
iv = iv_and_key[0:12];
key = iv_and_key[12:44];
} else {
iv = iv_and_key[0:16];
key = iv_and_key[16:48];
}
uint8[] iv = iv_and_key[0:iv_and_key.length-16];
uint8[] key = iv_and_key[iv_and_key.length-16:iv_and_key.length];
file_transfer.encryption = Encryption.OMEMO;
debug("Decrypting file %s from %s", file_transfer.file_name, file_transfer.server_file_name);

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@ -20,13 +20,15 @@ public class OmemoFileEncryptor : Dino.FileEncryptor, Object {
}
public FileMeta encrypt_file(Conversation conversation, FileTransfer file_transfer) throws FileSendError {
const uint KEY_SIZE = 32;
const uint IV_SIZE = 12;
var omemo_http_file_meta = new OmemoHttpFileMeta();
try {
//Create a key and use it to encrypt the file
uint8[] iv = new uint8[16];
uint8[] iv = new uint8[IV_SIZE];
Plugin.get_context().randomize(iv);
uint8[] key = new uint8[32];
uint8[] key = new uint8[KEY_SIZE];
Plugin.get_context().randomize(key);
SymmetricCipher cipher = new SymmetricCipher("AES-GCM");

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@ -12,6 +12,8 @@ private const string AES_128_GCM_URI = "urn:xmpp:ciphers:aes-128-gcm-nopadding";
public class Module : XmppStreamModule, Jet.EnvelopEncoding {
public static Xmpp.ModuleIdentity<Module> IDENTITY = new Xmpp.ModuleIdentity<Module>(NS_URI, "0396_jet_omemo");
private Omemo.Plugin plugin;
const uint KEY_SIZE = 16;
const uint IV_SIZE = 12;
public Module(Omemo.Plugin plugin) {
this.plugin = plugin;
@ -21,7 +23,7 @@ public class Module : XmppStreamModule, Jet.EnvelopEncoding {
if (stream.get_module(Jet.Module.IDENTITY) != null) {
stream.get_module(ServiceDiscovery.Module.IDENTITY).add_feature(stream, NS_URI);
stream.get_module(Jet.Module.IDENTITY).register_envelop_encoding(this);
stream.get_module(Jet.Module.IDENTITY).register_cipher(new AesGcmCipher(16, AES_128_GCM_URI));
stream.get_module(Jet.Module.IDENTITY).register_cipher(new AesGcmCipher(KEY_SIZE, IV_SIZE, AES_128_GCM_URI));
}
}
@ -114,17 +116,19 @@ public class Module : XmppStreamModule, Jet.EnvelopEncoding {
}
public class AesGcmCipher : Jet.Cipher, Object {
private int key_size;
private uint key_size;
private uint default_iv_size;
private string uri;
public AesGcmCipher(int key_size, string uri) {
public AesGcmCipher(uint key_size, uint default_iv_size, string uri) {
this.key_size = key_size;
this.default_iv_size = default_iv_size;
this.uri = uri;
}
public string get_cipher_uri() {
return uri;
}
public Jet.TransportSecret generate_random_secret() {
uint8[] iv = new uint8[16];
uint8[] iv = new uint8[default_iv_size];
Omemo.Plugin.get_context().randomize(iv);
uint8[] key = new uint8[key_size];
Omemo.Plugin.get_context().randomize(key);

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@ -145,6 +145,8 @@ public class TrustManager {
}
public EncryptState encrypt(MessageStanza message, Jid self_jid, Gee.List<Jid> recipients, XmppStream stream, Account account) {
const uint KEY_SIZE = 16;
const uint IV_SIZE = 12;
EncryptState status = new EncryptState();
if (!Plugin.ensure_context()) return status;
if (message.to == null) return status;
@ -153,9 +155,9 @@ public class TrustManager {
try {
//Create a key and use it to encrypt the message
uint8[] key = new uint8[16];
uint8[] key = new uint8[KEY_SIZE];
Plugin.get_context().randomize(key);
uint8[] iv = new uint8[16];
uint8[] iv = new uint8[IV_SIZE];
Plugin.get_context().randomize(iv);
uint8[] aes_encrypt_result = aes_encrypt(Cipher.AES_GCM_NOPADDING, key, iv, message.body.data);

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@ -5,7 +5,7 @@ using Signal;
namespace Dino.Plugins.Omemo {
private const string NS_URI = "eu.siacs.conversations.axolotl";
internal const string NS_URI = "eu.siacs.conversations.axolotl";
private const string NODE_DEVICELIST = NS_URI + ".devicelist";
private const string NODE_BUNDLES = NS_URI + ".bundles";
private const string NODE_VERIFICATION = NS_URI + ".verification";

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@ -211,8 +211,6 @@ int signal_vala_encrypt(signal_buffer **output,
int algo, mode, error_code = SG_ERR_UNKNOWN;
if (aes_cipher(cipher, key_len, &algo, &mode)) return SG_ERR_INVAL;
if (iv_len != 16 && iv_len != 12) return SG_ERR_INVAL;
gcry_cipher_hd_t ctx = {0};
if (gcry_cipher_open(&ctx, algo, mode, 0)) return SG_ERR_NOMEM;
@ -294,8 +292,6 @@ int signal_vala_decrypt(signal_buffer **output,
if (aes_cipher(cipher, key_len, &algo, &mode)) return SG_ERR_INVAL;
if (ciphertext_len == 0) return SG_ERR_INVAL;
if (iv_len != 16 && iv_len != 12) return SG_ERR_INVAL;
gcry_cipher_hd_t ctx = {0};
if (gcry_cipher_open(&ctx, algo, mode, 0)) return SG_ERR_NOMEM;