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profanity/src/omemo/omemo.c

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#include <sys/time.h>
#include <sys/stat.h>
#include <errno.h>
#include <glib.h>
#include <pthread.h>
#include <signal/key_helper.h>
#include <signal/protocol.h>
#include <signal/signal_protocol.h>
#include <signal/session_builder.h>
#include <signal/session_cipher.h>
#include <gcrypt.h>
#include "config/account.h"
#include "config/files.h"
#include "log.h"
#include "omemo/crypto.h"
#include "omemo/omemo.h"
#include "omemo/store.h"
#include "ui/ui.h"
#include "ui/window_list.h"
#include "xmpp/connection.h"
#include "xmpp/omemo.h"
#include "xmpp/xmpp.h"
static gboolean loaded;
static void omemo_generate_short_term_crypto_materials(ProfAccount *account);
static void load_identity(void);
static void load_sessions(void);
static void lock(void *user_data);
static void unlock(void *user_data);
static void omemo_log(int level, const char *message, size_t len, void *user_data);
static gboolean handle_own_device_list(const char *const jid, GList *device_list);
static gboolean handle_device_list_start_session(const char *const jid, GList *device_list);
static void free_omemo_key(omemo_key_t *key);
static char * omemo_fingerprint(ec_public_key *identity, gboolean formatted);
static unsigned char *omemo_fingerprint_decode(const char *const fingerprint, size_t *len);
static void cache_device_identity(const char *const jid, uint32_t device_id, ec_public_key *identity);
static void g_hash_table_free(GHashTable *hash_table);
typedef gboolean (*OmemoDeviceListHandler)(const char *const jid, GList *device_list);
struct omemo_context_t {
pthread_mutexattr_t attr;
pthread_mutex_t lock;
signal_context *signal;
uint32_t device_id;
GHashTable *device_list;
GHashTable *device_list_handler;
ratchet_identity_key_pair *identity_key_pair;
uint32_t registration_id;
uint32_t signed_pre_key_id;
signal_protocol_store_context *store;
GHashTable *session_store;
GHashTable *pre_key_store;
GHashTable *signed_pre_key_store;
identity_key_store_t identity_key_store;
GHashTable *device_ids;
GString *identity_filename;
GKeyFile *identity_keyfile;
GString *sessions_filename;
GKeyFile *sessions_keyfile;
GHashTable *known_devices;
};
static omemo_context omemo_ctx;
void
omemo_init(void)
{
log_info("OMEMO: initialising");
signal_crypto_provider crypto_provider = {
.random_func = omemo_random_func,
.hmac_sha256_init_func = omemo_hmac_sha256_init_func,
.hmac_sha256_update_func = omemo_hmac_sha256_update_func,
.hmac_sha256_final_func = omemo_hmac_sha256_final_func,
.hmac_sha256_cleanup_func = omemo_hmac_sha256_cleanup_func,
.sha512_digest_init_func = omemo_sha512_digest_init_func,
.sha512_digest_update_func = omemo_sha512_digest_update_func,
.sha512_digest_final_func = omemo_sha512_digest_final_func,
.sha512_digest_cleanup_func = omemo_sha512_digest_cleanup_func,
.encrypt_func = omemo_encrypt_func,
.decrypt_func = omemo_decrypt_func,
.user_data = NULL
};
if (omemo_crypto_init() != 0) {
cons_show("Error initializing OMEMO crypto");
}
pthread_mutexattr_init(&omemo_ctx.attr);
pthread_mutexattr_settype(&omemo_ctx.attr, PTHREAD_MUTEX_RECURSIVE);
pthread_mutex_init(&omemo_ctx.lock, &omemo_ctx.attr);
if (signal_context_create(&omemo_ctx.signal, &omemo_ctx) != 0) {
cons_show("Error initializing OMEMO context");
return;
}
if (signal_context_set_log_function(omemo_ctx.signal, omemo_log) != 0) {
cons_show("Error initializing OMEMO log");
}
if (signal_context_set_crypto_provider(omemo_ctx.signal, &crypto_provider) != 0) {
cons_show("Error initializing OMEMO crypto");
return;
}
signal_context_set_locking_functions(omemo_ctx.signal, lock, unlock);
signal_protocol_store_context_create(&omemo_ctx.store, omemo_ctx.signal);
omemo_ctx.session_store = session_store_new();
signal_protocol_session_store session_store = {
.load_session_func = load_session,
.get_sub_device_sessions_func = get_sub_device_sessions,
.store_session_func = store_session,
.contains_session_func = contains_session,
.delete_session_func = delete_session,
.delete_all_sessions_func = delete_all_sessions,
.destroy_func = NULL,
.user_data = omemo_ctx.session_store
};
signal_protocol_store_context_set_session_store(omemo_ctx.store, &session_store);
omemo_ctx.pre_key_store = pre_key_store_new();
signal_protocol_pre_key_store pre_key_store = {
.load_pre_key = load_pre_key,
.store_pre_key = store_pre_key,
.contains_pre_key = contains_pre_key,
.remove_pre_key = remove_pre_key,
.destroy_func = NULL,
.user_data = omemo_ctx.pre_key_store
};
signal_protocol_store_context_set_pre_key_store(omemo_ctx.store, &pre_key_store);
omemo_ctx.signed_pre_key_store = signed_pre_key_store_new();
signal_protocol_signed_pre_key_store signed_pre_key_store = {
.load_signed_pre_key = load_signed_pre_key,
.store_signed_pre_key = store_signed_pre_key,
.contains_signed_pre_key = contains_signed_pre_key,
.remove_signed_pre_key = remove_signed_pre_key,
.destroy_func = NULL,
.user_data = omemo_ctx.signed_pre_key_store
};
signal_protocol_store_context_set_signed_pre_key_store(omemo_ctx.store, &signed_pre_key_store);
identity_key_store_new(&omemo_ctx.identity_key_store);
signal_protocol_identity_key_store identity_key_store = {
.get_identity_key_pair = get_identity_key_pair,
.get_local_registration_id = get_local_registration_id,
.save_identity = save_identity,
.is_trusted_identity = is_trusted_identity,
.destroy_func = NULL,
.user_data = &omemo_ctx.identity_key_store
};
signal_protocol_store_context_set_identity_key_store(omemo_ctx.store, &identity_key_store);
loaded = FALSE;
omemo_ctx.device_list = g_hash_table_new_full(g_str_hash, g_str_equal, free, (GDestroyNotify)g_list_free);
omemo_ctx.device_list_handler = g_hash_table_new_full(g_str_hash, g_str_equal, free, NULL);
omemo_ctx.known_devices = g_hash_table_new_full(g_str_hash, g_str_equal, free, (GDestroyNotify)g_hash_table_free);
}
void
omemo_on_connect(ProfAccount *account)
{
char *omemodir = files_get_data_path(DIR_OMEMO);
GString *basedir = g_string_new(omemodir);
free(omemodir);
gchar *account_dir = str_replace(account->jid, "@", "_at_");
g_string_append(basedir, "/");
g_string_append(basedir, account_dir);
g_string_append(basedir, "/");
free(account_dir);
omemo_ctx.identity_filename = g_string_new(basedir->str);
g_string_append(omemo_ctx.identity_filename, "identity.txt");
omemo_ctx.sessions_filename = g_string_new(basedir->str);
g_string_append(omemo_ctx.sessions_filename, "sessions.txt");
errno = 0;
int res = g_mkdir_with_parents(basedir->str, S_IRWXU);
if (res == -1) {
char *errmsg = strerror(errno);
if (errmsg) {
log_error("OMEMO: error creating directory: %s, %s", basedir->str, errmsg);
} else {
log_error("OMEMO: creating directory: %s", basedir->str);
}
}
omemo_ctx.identity_keyfile = g_key_file_new();
if (g_key_file_load_from_file(omemo_ctx.identity_keyfile, omemo_ctx.identity_filename->str, G_KEY_FILE_KEEP_COMMENTS, NULL)) {
load_identity();
omemo_generate_short_term_crypto_materials(account);
}
omemo_ctx.sessions_keyfile = g_key_file_new();
if (g_key_file_load_from_file(omemo_ctx.sessions_keyfile, omemo_ctx.sessions_filename->str, G_KEY_FILE_KEEP_COMMENTS, NULL)) {
load_sessions();
}
}
void
omemo_generate_crypto_materials(ProfAccount *account)
{
if (loaded) {
return;
}
gcry_randomize(&omemo_ctx.device_id, 4, GCRY_VERY_STRONG_RANDOM);
omemo_ctx.device_id &= 0x7fffffff;
signal_protocol_key_helper_generate_identity_key_pair(&omemo_ctx.identity_key_pair, omemo_ctx.signal);
signal_protocol_key_helper_generate_registration_id(&omemo_ctx.registration_id, 0, omemo_ctx.signal);
ec_public_key_serialize(&omemo_ctx.identity_key_store.public, ratchet_identity_key_pair_get_public(omemo_ctx.identity_key_pair));
ec_private_key_serialize(&omemo_ctx.identity_key_store.private, ratchet_identity_key_pair_get_private(omemo_ctx.identity_key_pair));
g_key_file_set_uint64(omemo_ctx.identity_keyfile, OMEMO_STORE_GROUP_IDENTITY, OMEMO_STORE_KEY_DEVICE_ID, omemo_ctx.device_id);
g_key_file_set_uint64(omemo_ctx.identity_keyfile, OMEMO_STORE_GROUP_IDENTITY, OMEMO_STORE_KEY_REGISTRATION_ID, omemo_ctx.registration_id);
char *identity_key_public = g_base64_encode(signal_buffer_data(omemo_ctx.identity_key_store.public), signal_buffer_len(omemo_ctx.identity_key_store.public));
g_key_file_set_string(omemo_ctx.identity_keyfile, OMEMO_STORE_GROUP_IDENTITY, OMEMO_STORE_KEY_IDENTITY_KEY_PUBLIC, identity_key_public);
g_free(identity_key_public);
char *identity_key_private = g_base64_encode(signal_buffer_data(omemo_ctx.identity_key_store.private), signal_buffer_len(omemo_ctx.identity_key_store.private));
g_key_file_set_string(omemo_ctx.identity_keyfile, OMEMO_STORE_GROUP_IDENTITY, OMEMO_STORE_KEY_IDENTITY_KEY_PRIVATE, identity_key_private);
g_free(identity_key_private);
omemo_identity_keyfile_save();
omemo_generate_short_term_crypto_materials(account);
}
static void
omemo_generate_short_term_crypto_materials(ProfAccount *account)
{
unsigned int start;
gcry_randomize(&start, sizeof(unsigned int), GCRY_VERY_STRONG_RANDOM);
signal_protocol_key_helper_pre_key_list_node *pre_keys_head;
signal_protocol_key_helper_generate_pre_keys(&pre_keys_head, start, 100, omemo_ctx.signal);
session_signed_pre_key *signed_pre_key;
struct timeval tv;
gettimeofday(&tv, NULL);
unsigned long long timestamp = (unsigned long long)(tv.tv_sec) * 1000 + (unsigned long long)(tv.tv_usec) / 1000;
omemo_ctx.signed_pre_key_id = 1;
signal_protocol_key_helper_generate_signed_pre_key(&signed_pre_key, omemo_ctx.identity_key_pair, omemo_ctx.signed_pre_key_id, timestamp, omemo_ctx.signal);
signal_protocol_key_helper_pre_key_list_node *p;
for (p = pre_keys_head; p != NULL; p = signal_protocol_key_helper_key_list_next(p)) {
session_pre_key *prekey = signal_protocol_key_helper_key_list_element(p);
signal_protocol_pre_key_store_key(omemo_ctx.store, prekey);
}
signal_protocol_signed_pre_key_store_key(omemo_ctx.store, signed_pre_key);
loaded = TRUE;
/* Ensure we get our current device list, and it gets updated with our
* device_id */
g_hash_table_insert(omemo_ctx.device_list_handler, strdup(account->jid), handle_own_device_list);
omemo_devicelist_request(account->jid);
omemo_bundle_publish();
}
void
omemo_start_session(const char *const barejid)
{
log_info("OMEMO: start session with %s", barejid);
GList *device_list = g_hash_table_lookup(omemo_ctx.device_list, barejid);
if (!device_list) {
log_info("OMEMO: missing device list for %s", barejid);
omemo_devicelist_request(barejid);
g_hash_table_insert(omemo_ctx.device_list_handler, strdup(barejid), handle_device_list_start_session);
return;
}
GList *device_id;
for (device_id = device_list; device_id != NULL; device_id = device_id->next) {
omemo_bundle_request(barejid, GPOINTER_TO_INT(device_id->data), omemo_start_device_session_handle_bundle, free, strdup(barejid));
}
}
gboolean
omemo_loaded(void)
{
return loaded;
}
uint32_t
omemo_device_id(void)
{
return omemo_ctx.device_id;
}
void
omemo_identity_key(unsigned char **output, size_t *length)
{
signal_buffer *buffer = NULL;
ec_public_key_serialize(&buffer, ratchet_identity_key_pair_get_public(omemo_ctx.identity_key_pair));
*length = signal_buffer_len(buffer);
*output = malloc(*length);
memcpy(*output, signal_buffer_data(buffer), *length);
signal_buffer_free(buffer);
}
void
omemo_signed_prekey(unsigned char **output, size_t *length)
{
session_signed_pre_key *signed_pre_key;
signal_buffer *buffer = NULL;
signal_protocol_signed_pre_key_load_key(omemo_ctx.store, &signed_pre_key, omemo_ctx.signed_pre_key_id);
ec_public_key_serialize(&buffer, ec_key_pair_get_public(session_signed_pre_key_get_key_pair(signed_pre_key)));
*length = signal_buffer_len(buffer);
*output = malloc(*length);
memcpy(*output, signal_buffer_data(buffer), *length);
signal_buffer_free(buffer);
}
void
omemo_signed_prekey_signature(unsigned char **output, size_t *length)
{
session_signed_pre_key *signed_pre_key;
signal_protocol_signed_pre_key_load_key(omemo_ctx.store, &signed_pre_key, omemo_ctx.signed_pre_key_id);
*length = session_signed_pre_key_get_signature_len(signed_pre_key);
*output = malloc(*length);
memcpy(*output, session_signed_pre_key_get_signature(signed_pre_key), *length);
}
void
omemo_prekeys(GList **prekeys, GList **ids, GList **lengths)
{
GHashTableIter iter;
gpointer id;
g_hash_table_iter_init(&iter, omemo_ctx.pre_key_store);
while (g_hash_table_iter_next(&iter, &id, NULL)) {
session_pre_key *pre_key;
int ret;
ret = signal_protocol_pre_key_load_key(omemo_ctx.store, &pre_key, GPOINTER_TO_INT(id));
if (ret != SG_SUCCESS) {
continue;
}
signal_buffer *public_key;
ec_public_key_serialize(&public_key, ec_key_pair_get_public(session_pre_key_get_key_pair(pre_key)));
size_t length = signal_buffer_len(public_key);
unsigned char *prekey_value = malloc(length);
memcpy(prekey_value, signal_buffer_data(public_key), length);
*prekeys = g_list_append(*prekeys, prekey_value);
*ids = g_list_append(*ids, GINT_TO_POINTER(id));
*lengths = g_list_append(*lengths, GINT_TO_POINTER(length));
}
}
void
omemo_set_device_list(const char *const from, GList * device_list)
{
Jid *jid = jid_create(from);
g_hash_table_insert(omemo_ctx.device_list, strdup(jid->barejid), device_list);
if (strchr(jid->barejid, '@') == NULL) {
// barejid is server so we should handle it as our own device list
g_hash_table_insert(omemo_ctx.device_list_handler, strdup(jid->barejid), handle_own_device_list);
}
OmemoDeviceListHandler handler = g_hash_table_lookup(omemo_ctx.device_list_handler, jid->barejid);
if (handler) {
gboolean keep = handler(jid->barejid, device_list);
if (!keep) {
g_hash_table_remove(omemo_ctx.device_list_handler, jid->barejid);
}
}
free(jid);
}
GKeyFile *
omemo_identity_keyfile(void)
{
return omemo_ctx.identity_keyfile;
}
void
omemo_identity_keyfile_save(void)
{
GError *error = NULL;
if (!g_key_file_save_to_file(omemo_ctx.identity_keyfile, omemo_ctx.identity_filename->str, &error)) {
log_error("OMEMO: error saving identity to: %s, %s", omemo_ctx.identity_filename->str, error->message);
}
}
GKeyFile *
omemo_sessions_keyfile(void)
{
return omemo_ctx.sessions_keyfile;
}
void
omemo_sessions_keyfile_save(void)
{
GError *error = NULL;
if (!g_key_file_save_to_file(omemo_ctx.sessions_keyfile, omemo_ctx.sessions_filename->str, &error)) {
log_error("OMEMO: error saving sessions to: %s, %s", omemo_ctx.sessions_filename->str, error->message);
}
}
void
omemo_start_device_session(const char *const jid, uint32_t device_id,
GList *prekeys, uint32_t signed_prekey_id,
const unsigned char *const signed_prekey_raw, size_t signed_prekey_len,
const unsigned char *const signature, size_t signature_len,
const unsigned char *const identity_key_raw, size_t identity_key_len)
{
signal_protocol_address address = {
.name = strdup(jid),
.name_len = strlen(jid),
.device_id = device_id,
};
ec_public_key *identity_key;
curve_decode_point(&identity_key, identity_key_raw, identity_key_len, omemo_ctx.signal);
cache_device_identity(jid, device_id, identity_key);
gboolean trusted = is_trusted_identity(&address, (uint8_t *)identity_key_raw, identity_key_len, &omemo_ctx.identity_key_store);
Jid *ownjid = jid_create(session_get_account_name());
if (g_strcmp0(jid, ownjid->barejid) == 0) {
char *fingerprint = omemo_fingerprint(identity_key, TRUE);
cons_show("Available device identity for %s: %s%s", ownjid->barejid, fingerprint, trusted ? " (trusted)" : "");
if (trusted) {
cons_show("You can untrust it with '/omemo untrust %s <fingerprint>'", ownjid->barejid);
} else {
cons_show("You can trust it with '/omemo trust %s <fingerprint>'", ownjid->barejid);
}
free(fingerprint);
}
ProfChatWin *chatwin = wins_get_chat(jid);
if (chatwin) {
char *fingerprint = omemo_fingerprint(identity_key, TRUE);
win_println((ProfWin *)chatwin, THEME_DEFAULT, '-', "Available device identity: %s%s", fingerprint, trusted ? " (trusted)" : "");
if (trusted) {
win_println((ProfWin *)chatwin, THEME_DEFAULT, '-', "You can untrust it with '/omemo untrust <fingerprint>'");
} else {
win_println((ProfWin *)chatwin, THEME_DEFAULT, '-', "You can trust it with '/omemo trust <fingerprint>'");
}
free(fingerprint);
}
if (!trusted) {
goto out;
}
if (!contains_session(&address, omemo_ctx.session_store)) {
int res;
session_pre_key_bundle *bundle;
signal_protocol_address *address;
address = malloc(sizeof(signal_protocol_address));
address->name = strdup(jid);
address->name_len = strlen(jid);
address->device_id = device_id;
session_builder *builder;
res = session_builder_create(&builder, omemo_ctx.store, address, omemo_ctx.signal);
if (res != 0) {
log_error("OMEMO: cannot create session builder for %s device %d", jid, device_id);
goto out;
}
int prekey_index;
gcry_randomize(&prekey_index, sizeof(int), GCRY_STRONG_RANDOM);
prekey_index %= g_list_length(prekeys);
omemo_key_t *prekey = g_list_nth_data(prekeys, prekey_index);
ec_public_key *prekey_public;
curve_decode_point(&prekey_public, prekey->data, prekey->length, omemo_ctx.signal);
ec_public_key *signed_prekey;
curve_decode_point(&signed_prekey, signed_prekey_raw, signed_prekey_len, omemo_ctx.signal);
res = session_pre_key_bundle_create(&bundle, 0, device_id, prekey->id, prekey_public, signed_prekey_id, signed_prekey, signature, signature_len, identity_key);
if (res != 0) {
log_error("OMEMO: cannot create pre key bundle for %s device %d", jid, device_id);
goto out;
}
res = session_builder_process_pre_key_bundle(builder, bundle);
if (res != 0) {
log_error("OMEMO: cannot process pre key bundle for %s device %d", jid, device_id);
goto out;
}
log_info("OMEMO: create session with %s device %d", jid, device_id);
}
out:
g_list_free_full(prekeys, (GDestroyNotify)free_omemo_key);
free(ownjid);
}
gboolean
omemo_on_message_send(ProfChatWin *chatwin, const char *const message, gboolean request_receipt)
{
int res;
Jid *jid = jid_create(session_get_account_name());
GList *recipient_device_id = g_hash_table_lookup(omemo_ctx.device_list, chatwin->barejid);
if (!recipient_device_id) {
return FALSE;
}
GList *sender_device_id = g_hash_table_lookup(omemo_ctx.device_list, jid->barejid);
/* TODO generate fresh AES-GCM materials */
/* TODO encrypt message */
unsigned char *key;
unsigned char *iv;
unsigned char *ciphertext;
unsigned char *tag;
unsigned char *key_tag;
size_t ciphertext_len, tag_len;
ciphertext_len = strlen(message);
ciphertext = malloc(ciphertext_len);
tag_len = AES128_GCM_TAG_LENGTH;
tag = gcry_malloc_secure(tag_len);
key_tag = gcry_malloc_secure(AES128_GCM_KEY_LENGTH + AES128_GCM_TAG_LENGTH);
key = gcry_random_bytes_secure(AES128_GCM_KEY_LENGTH, GCRY_VERY_STRONG_RANDOM);
iv = gcry_random_bytes_secure(AES128_GCM_IV_LENGTH, GCRY_VERY_STRONG_RANDOM);
res = aes128gcm_encrypt(ciphertext, &ciphertext_len, tag, &tag_len, (const unsigned char * const)message, strlen(message), iv, key);
if (res != 0) {
log_error("OMEMO: cannot encrypt message");
return FALSE;
}
memcpy(key_tag, key, AES128_GCM_KEY_LENGTH);
memcpy(key_tag + AES128_GCM_KEY_LENGTH, tag, AES128_GCM_TAG_LENGTH);
GList *keys = NULL;
GList *device_ids_iter;
for (device_ids_iter = recipient_device_id; device_ids_iter != NULL; device_ids_iter = device_ids_iter->next) {
int res;
ciphertext_message *ciphertext;
session_cipher *cipher;
signal_protocol_address address = {
.name = chatwin->barejid,
.name_len = strlen(chatwin->barejid),
.device_id = GPOINTER_TO_INT(device_ids_iter->data)
};
res = session_cipher_create(&cipher, omemo_ctx.store, &address, omemo_ctx.signal);
if (res != 0) {
log_error("OMEMO: cannot create cipher for %s device id %d", address.name, address.device_id);
continue;
}
res = session_cipher_encrypt(cipher, key_tag, AES128_GCM_KEY_LENGTH + AES128_GCM_TAG_LENGTH, &ciphertext);
if (res != 0) {
log_error("OMEMO: cannot encrypt key for %s device id %d", address.name, address.device_id);
continue;
}
signal_buffer *buffer = ciphertext_message_get_serialized(ciphertext);
omemo_key_t *key = malloc(sizeof(omemo_key_t));
key->data = signal_buffer_data(buffer);
key->length = signal_buffer_len(buffer);
key->device_id = GPOINTER_TO_INT(device_ids_iter->data);
key->prekey = ciphertext_message_get_type(ciphertext) == CIPHERTEXT_PREKEY_TYPE;
keys = g_list_append(keys, key);
}
for (device_ids_iter = sender_device_id; device_ids_iter != NULL; device_ids_iter = device_ids_iter->next) {
int res;
ciphertext_message *ciphertext;
session_cipher *cipher;
signal_protocol_address address = {
.name = jid->barejid,
.name_len = strlen(jid->barejid),
.device_id = GPOINTER_TO_INT(device_ids_iter->data)
};
res = session_cipher_create(&cipher, omemo_ctx.store, &address, omemo_ctx.signal);
if (res != 0) {
log_error("OMEMO: cannot create cipher for %s device id %d", address.name, address.device_id);
continue;
}
res = session_cipher_encrypt(cipher, key_tag, AES128_GCM_KEY_LENGTH + AES128_GCM_TAG_LENGTH, &ciphertext);
if (res != 0) {
log_error("OMEMO: cannot encrypt key for %s device id %d", address.name, address.device_id);
continue;
}
signal_buffer *buffer = ciphertext_message_get_serialized(ciphertext);
omemo_key_t *key = malloc(sizeof(omemo_key_t));
key->data = signal_buffer_data(buffer);
key->length = signal_buffer_len(buffer);
key->device_id = GPOINTER_TO_INT(device_ids_iter->data);
key->prekey = ciphertext_message_get_type(ciphertext) == CIPHERTEXT_PREKEY_TYPE;
keys = g_list_append(keys, key);
}
char *id = message_send_chat_omemo(chatwin->barejid, omemo_ctx.device_id, keys, iv, AES128_GCM_IV_LENGTH, ciphertext, ciphertext_len, request_receipt);
chat_log_omemo_msg_out(chatwin->barejid, message);
chatwin_outgoing_msg(chatwin, message, id, PROF_MSG_OMEMO, request_receipt);
free(id);
g_list_free_full(keys, free);
free(ciphertext);
gcry_free(key);
gcry_free(iv);
gcry_free(tag);
gcry_free(key_tag);
return TRUE;
}
char *
omemo_on_message_recv(const char *const from, uint32_t sid,
const unsigned char *const iv, size_t iv_len, GList *keys,
const unsigned char *const payload, size_t payload_len)
{
int res;
GList *key_iter;
omemo_key_t *key = NULL;
for (key_iter = keys; key_iter != NULL; key_iter = key_iter->next) {
if (((omemo_key_t *)key_iter->data)->device_id == omemo_ctx.device_id) {
key = key_iter->data;
break;
}
}
if (!key) {
log_warning("OMEMO: Received a message with no corresponding key");
return NULL;
}
session_cipher *cipher;
signal_buffer *plaintext_key;
signal_protocol_address address = {
.name = from,
.name_len = strlen(from),
.device_id = sid
};
res = session_cipher_create(&cipher, omemo_ctx.store, &address, omemo_ctx.signal);
if (res != 0) {
log_error("OMEMO: cannot create session cipher");
return NULL;
}
if (key->prekey) {
log_debug("OMEMO: decrypting message with prekey");
pre_key_signal_message *message;
pre_key_signal_message_deserialize(&message, key->data, key->length, omemo_ctx.signal);
/* Replace used pre_key in bundle */
uint32_t pre_key_id = pre_key_signal_message_get_pre_key_id(message);
g_hash_table_remove(omemo_ctx.pre_key_store, GINT_TO_POINTER(pre_key_id));
ec_key_pair *ec_pair;
session_pre_key *new_pre_key;
curve_generate_key_pair(omemo_ctx.signal, &ec_pair);
session_pre_key_create(&new_pre_key, pre_key_id, ec_pair);
g_hash_table_insert(omemo_ctx.pre_key_store, GINT_TO_POINTER(pre_key_id), new_pre_key);
omemo_bundle_publish();
/* Start a new session */
omemo_bundle_request(from, sid, omemo_start_device_session_handle_bundle, free, strdup(from));
/* Try to decrypt message anyway, it will fail */
res = session_cipher_decrypt_pre_key_signal_message(cipher, message, NULL, &plaintext_key);
} else {
log_debug("OMEMO: decrypting message with existing session");
signal_message *message;
signal_message_deserialize(&message, key->data, key->length, omemo_ctx.signal);
res = session_cipher_decrypt_signal_message(cipher, message, NULL, &plaintext_key);
}
if (res != 0) {
log_debug("OMEMO: cannot to decrypt message key");
return NULL;
}
if (signal_buffer_len(plaintext_key) != AES128_GCM_KEY_LENGTH + AES128_GCM_TAG_LENGTH) {
log_error("OMEMO: invalid key length");
signal_buffer_free(plaintext_key);
return NULL;
}
size_t plaintext_len = payload_len;
unsigned char *plaintext = malloc(plaintext_len + 1);
res = aes128gcm_decrypt(plaintext, &plaintext_len, payload, payload_len, iv,
signal_buffer_data(plaintext_key),
signal_buffer_data(plaintext_key) + AES128_GCM_KEY_LENGTH);
if (res != 0) {
log_error("OMEMO: cannot decrypt message: %s", gcry_strerror(res));
signal_buffer_free(plaintext_key);
free(plaintext);
return NULL;
}
plaintext[plaintext_len] = '\0';
return (char *)plaintext;
}
char *
omemo_format_fingerprint(const char *const fingerprint)
{
char *output = malloc(strlen(fingerprint) + strlen(fingerprint) / 8);
int i, j;
for (i = 0, j = 0; i < strlen(fingerprint); i++) {
if (i > 0 && i % 8 == 0) {
output[j++] = '-';
}
output[j++] = fingerprint[i];
}
output[j] = '\0';
return output;
}
char *
omemo_own_fingerprint(gboolean formatted)
{
ec_public_key *identity = ratchet_identity_key_pair_get_public(omemo_ctx.identity_key_pair);
return omemo_fingerprint(identity, formatted);
}
static char *
omemo_fingerprint(ec_public_key *identity, gboolean formatted)
{
int i;
signal_buffer *identity_public_key;
ec_public_key_serialize(&identity_public_key, identity);
size_t identity_public_key_len = signal_buffer_len(identity_public_key);
unsigned char *identity_public_key_data = signal_buffer_data(identity_public_key);
/* Skip first byte corresponding to signal DJB_TYPE */
identity_public_key_len--;
identity_public_key_data = &identity_public_key_data[1];
char *fingerprint = malloc(identity_public_key_len * 2 + 1);
for (i = 0; i < identity_public_key_len; i++) {
fingerprint[i * 2] = (identity_public_key_data[i] & 0xf0) >> 4;
fingerprint[i * 2] += '0';
if (fingerprint[i * 2] > '9') {
fingerprint[i * 2] += 0x27;
}
fingerprint[(i * 2) + 1] = identity_public_key_data[i] & 0x0f;
fingerprint[(i * 2) + 1] += '0';
if (fingerprint[(i * 2) + 1] > '9') {
fingerprint[(i * 2) + 1] += 0x27;
}
}
fingerprint[i * 2] = '\0';
signal_buffer_free(identity_public_key);
if (!formatted) {
return fingerprint;
} else {
char *formatted_fingerprint = omemo_format_fingerprint(fingerprint);
free(fingerprint);
return formatted_fingerprint;
}
}
static unsigned char *
omemo_fingerprint_decode(const char *const fingerprint, size_t *len)
{
unsigned char *output = malloc(strlen(fingerprint) / 2 + 1);
int i;
int j;
for (i = 0, j = 0; i < strlen(fingerprint);) {
if (!g_ascii_isxdigit(fingerprint[i])) {
i++;
continue;
}
output[j] = g_ascii_xdigit_value(fingerprint[i++]) << 4;
output[j] |= g_ascii_xdigit_value(fingerprint[i++]);
j++;
}
*len = j;
return output;
}
void
omemo_trust(const char *const jid, const char *const fingerprint_formatted)
{
size_t len;
GHashTable *known_identities = g_hash_table_lookup(omemo_ctx.known_devices, jid);
if (!known_identities) {
log_warning("OMEMO: cannot trust unknown device: %s", fingerprint_formatted);
cons_show("Cannot trust unknown device: %s", fingerprint_formatted);
return;
}
/* Unformat fingerprint */
char *fingerprint = malloc(strlen(fingerprint_formatted));
int i;
int j;
for (i = 0, j = 0; fingerprint_formatted[i] != '\0'; i++) {
if (!g_ascii_isxdigit(fingerprint_formatted[i])) {
continue;
}
fingerprint[j++] = fingerprint_formatted[i];
}
fingerprint[j] = '\0';
uint32_t device_id = GPOINTER_TO_INT(g_hash_table_lookup(known_identities, fingerprint));
free(fingerprint);
if (!device_id) {
log_warning("OMEMO: cannot trust unknown device: %s", fingerprint_formatted);
cons_show("Cannot trust unknown device: %s", fingerprint_formatted);
return;
}
/* TODO should not hardcode DJB_TYPE here
* should instead store identity key in known_identities along with
* device_id */
signal_protocol_address address = {
.name = jid,
.name_len = strlen(jid),
.device_id = device_id,
};
unsigned char *fingerprint_raw = omemo_fingerprint_decode(fingerprint_formatted, &len);
unsigned char djb_type[] = {'\x05'};
signal_buffer *buffer = signal_buffer_create(djb_type, 1);
buffer = signal_buffer_append(buffer, fingerprint_raw, len);
save_identity(&address, signal_buffer_data(buffer), signal_buffer_len(buffer), &omemo_ctx.identity_key_store);
free(fingerprint_raw);
signal_buffer_free(buffer);
omemo_bundle_request(jid, device_id, omemo_start_device_session_handle_bundle, free, strdup(jid));
}
void
omemo_untrust(const char *const jid, const char *const fingerprint_formatted)
{
size_t len;
unsigned char *fingerprint = omemo_fingerprint_decode(fingerprint_formatted, &len);
GHashTableIter iter;
gpointer key, value;
g_hash_table_iter_init(&iter, omemo_ctx.identity_key_store.trusted);
while (g_hash_table_iter_next(&iter, &key, &value)) {
signal_buffer *buffer = value;
unsigned char *original = signal_buffer_data(buffer);
/* Skip DJB_TYPE byte */
original++;
if ((signal_buffer_len(buffer) - 1) == len && memcmp(original, fingerprint, len) == 0) {
g_hash_table_remove(omemo_ctx.identity_key_store.trusted, key);
}
}
free(fingerprint);
}
static void
lock(void *user_data)
{
omemo_context *ctx = (omemo_context *)user_data;
pthread_mutex_lock(&ctx->lock);
}
static void
unlock(void *user_data)
{
omemo_context *ctx = (omemo_context *)user_data;
pthread_mutex_unlock(&ctx->lock);
}
static void
omemo_log(int level, const char *message, size_t len, void *user_data)
{
switch (level) {
case SG_LOG_ERROR:
log_error("OMEMO: %s", message);
break;
case SG_LOG_WARNING:
log_warning("OMEMO: %s", message);
break;
case SG_LOG_NOTICE:
case SG_LOG_INFO:
log_info("OMEMO: %s", message);
break;
case SG_LOG_DEBUG:
log_debug("OMEMO: %s", message);
break;
}
}
static gboolean
handle_own_device_list(const char *const jid, GList *device_list)
{
if (!g_list_find(device_list, GINT_TO_POINTER(omemo_ctx.device_id))) {
gpointer original_jid;
g_hash_table_steal_extended(omemo_ctx.device_list, jid, &original_jid, NULL);
free(original_jid);
device_list = g_list_append(device_list, GINT_TO_POINTER(omemo_ctx.device_id));
g_hash_table_insert(omemo_ctx.device_list, strdup(jid), device_list);
omemo_devicelist_publish(device_list);
}
GList *device_id;
for (device_id = device_list; device_id != NULL; device_id = device_id->next) {
omemo_bundle_request(jid, GPOINTER_TO_INT(device_id->data), omemo_start_device_session_handle_bundle, free, strdup(jid));
}
return TRUE;
}
static gboolean
handle_device_list_start_session(const char *const jid, GList *device_list)
{
omemo_start_session(jid);
return FALSE;
}
static void
free_omemo_key(omemo_key_t *key)
{
if (key == NULL) {
return;
}
free((void *)key->data);
free(key);
}
static void
load_identity(void)
{
omemo_ctx.device_id = g_key_file_get_uint64(omemo_ctx.identity_keyfile, OMEMO_STORE_GROUP_IDENTITY, OMEMO_STORE_KEY_DEVICE_ID, NULL);
omemo_ctx.registration_id = g_key_file_get_uint64(omemo_ctx.identity_keyfile, OMEMO_STORE_GROUP_IDENTITY, OMEMO_STORE_KEY_REGISTRATION_ID, NULL);
char *identity_key_public_b64 = g_key_file_get_string(omemo_ctx.identity_keyfile, OMEMO_STORE_GROUP_IDENTITY, OMEMO_STORE_KEY_IDENTITY_KEY_PUBLIC, NULL);
size_t identity_key_public_len;
unsigned char *identity_key_public = g_base64_decode(identity_key_public_b64, &identity_key_public_len);
omemo_ctx.identity_key_store.public = signal_buffer_create(identity_key_public, identity_key_public_len);
char *identity_key_private_b64 = g_key_file_get_string(omemo_ctx.identity_keyfile, OMEMO_STORE_GROUP_IDENTITY, OMEMO_STORE_KEY_IDENTITY_KEY_PRIVATE, NULL);
size_t identity_key_private_len;
unsigned char *identity_key_private = g_base64_decode(identity_key_private_b64, &identity_key_private_len);
omemo_ctx.identity_key_store.private = signal_buffer_create(identity_key_private, identity_key_private_len);
signal_buffer_create(identity_key_private, identity_key_private_len);
ec_public_key *public_key;
curve_decode_point(&public_key, identity_key_public, identity_key_public_len, omemo_ctx.signal);
ec_private_key *private_key;
curve_decode_private_point(&private_key, identity_key_private, identity_key_private_len, omemo_ctx.signal);
ratchet_identity_key_pair_create(&omemo_ctx.identity_key_pair, public_key, private_key);
g_free(identity_key_public);
g_free(identity_key_private);
char **keys = g_key_file_get_keys(omemo_ctx.identity_keyfile, OMEMO_STORE_GROUP_TRUST, NULL, NULL);
if (keys) {
int i;
for (i = 0; keys[i] != NULL; i++) {
char *key_b64 = g_key_file_get_string(omemo_ctx.identity_keyfile, OMEMO_STORE_GROUP_TRUST, keys[i], NULL);
size_t key_len;
unsigned char *key = g_base64_decode(key_b64, &key_len);
signal_buffer *buffer = signal_buffer_create(key, key_len);
g_hash_table_insert(omemo_ctx.identity_key_store.trusted, keys[i], buffer);
free(key_b64);
}
}
}
static void
load_sessions(void)
{
int i;
char **groups = g_key_file_get_groups(omemo_ctx.sessions_keyfile, NULL);
if (groups) {
for (i = 0; groups[i] != NULL; i++) {
int j;
GHashTable *device_store = NULL;
device_store = g_hash_table_lookup(omemo_ctx.session_store, groups[i]);
if (!device_store) {
device_store = g_hash_table_new_full(g_direct_hash, g_direct_equal, NULL, (GDestroyNotify)signal_buffer_free);
g_hash_table_insert(omemo_ctx.session_store, groups[i], device_store);
}
char **keys = g_key_file_get_keys(omemo_ctx.sessions_keyfile, groups[i], NULL, NULL);
for (j = 0; keys[j] != NULL; j++) {
uint32_t id = strtoul(keys[j], NULL, 10);
char *record_b64 = g_key_file_get_string(omemo_ctx.sessions_keyfile, groups[i], keys[j], NULL);
size_t record_len;
unsigned char *record = g_base64_decode(record_b64, &record_len);
signal_buffer *buffer = signal_buffer_create(record, record_len);
g_hash_table_insert(device_store, GINT_TO_POINTER(id), buffer);
free(record_b64);
}
}
}
}
static void
cache_device_identity(const char *const jid, uint32_t device_id, ec_public_key *identity)
{
GHashTable *known_identities = g_hash_table_lookup(omemo_ctx.known_devices, jid);
if (!known_identities) {
known_identities = g_hash_table_new_full(g_str_hash, g_str_equal, free, NULL);
g_hash_table_insert(omemo_ctx.known_devices, strdup(jid), known_identities);
}
char *fingerprint = omemo_fingerprint(identity, FALSE);
log_info("OMEMO: cache identity for %s:%d: %s", jid, device_id, fingerprint);
g_hash_table_insert(known_identities, fingerprint, GINT_TO_POINTER(device_id));
}
static void
g_hash_table_free(GHashTable *hash_table)
{
g_hash_table_remove_all(hash_table);
g_hash_table_unref(hash_table);
}
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