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Don't trust unknown identity keys

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Also add long terme storage of known identity keys.
If a key is stored it means it is trusted.
This commit is contained in:
Paul Fariello
2019-03-07 19:38:15 +01:40
parent 249701fe7a
commit 23485eb4e7
4 changed files with 105 additions and 55 deletions
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141
src/omemo/omemo.c
View File

@@ -25,6 +25,8 @@
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);
@@ -188,64 +190,19 @@ omemo_on_connect(ProfAccount *account)
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)) {
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);
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)) {
int i;
char **groups = g_key_file_get_groups(omemo_ctx.sessions_keyfile, NULL);
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);
}
}
load_sessions();
}
}
void
omemo_generate_crypto_materials(ProfAccount *account)
{
GError *error = NULL;
if (loaded) {
return;
}
@@ -268,9 +225,7 @@ omemo_generate_crypto_materials(ProfAccount *account)
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);
if (!g_key_file_save_to_file(omemo_ctx.identity_keyfile, omemo_ctx.identity_filename->str, &error)) {
log_error("Error saving OMEMO identity to: %s, %s", omemo_ctx.identity_filename->str, error->message);
}
omemo_identity_keyfile_save();
omemo_generate_short_term_crypto_materials(account);
}
@@ -426,6 +381,22 @@ omemo_set_device_list(const char *const jid, GList * device_list)
free(barejid);
}
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("Error saving OMEMO identity to: %s, %s", omemo_ctx.identity_filename->str, error->message);
}
}
GKeyFile *
omemo_sessions_keyfile(void)
{
@@ -802,3 +773,73 @@ free_omemo_key(omemo_key_t *key)
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);
}
}
}
}

2
src/omemo/omemo.h
View File

@@ -26,6 +26,8 @@ void omemo_signed_prekey(unsigned char **output, size_t *length);
void omemo_signed_prekey_signature(unsigned char **output, size_t *length);
void omemo_prekeys(GList **prekeys, GList **ids, GList **lengths);
void omemo_set_device_list(const char *const jid, GList * device_list);
GKeyFile *omemo_identity_keyfile(void);
void omemo_identity_keyfile_save(void);
GKeyFile *omemo_sessions_keyfile(void);
void omemo_sessions_keyfile_save(void);
char *omemo_fingerprint(const unsigned char *const identity_key_public, size_t len);

14
src/omemo/store.c
View File

@@ -26,7 +26,7 @@ signed_pre_key_store_new(void)
void
identity_key_store_new(identity_key_store_t *identity_key_store)
{
identity_key_store->identity_key_store = g_hash_table_new_full(g_str_hash, g_str_equal, free, (GDestroyNotify)signal_buffer_free);
identity_key_store->trusted = g_hash_table_new_full(g_str_hash, g_str_equal, free, (GDestroyNotify)signal_buffer_free);
identity_key_store->private = NULL;
identity_key_store->public = NULL;
}
@@ -279,7 +279,13 @@ save_identity(const signal_protocol_address *address, uint8_t *key_data,
char *node = g_strdup_printf("%s:%d", address->name, address->device_id);
signal_buffer *buffer = signal_buffer_create(key_data, key_len);
g_hash_table_insert(identity_key_store->identity_key_store, node, buffer);
g_hash_table_insert(identity_key_store->trusted, strdup(node), buffer);
char *key_b64 = g_base64_encode(key_data, key_len);
g_key_file_set_string(omemo_identity_keyfile(), OMEMO_STORE_GROUP_TRUST, node, key_b64);
omemo_identity_keyfile_save();
free(node);
return SG_SUCCESS;
}
@@ -292,9 +298,9 @@ is_trusted_identity(const signal_protocol_address *address, uint8_t *key_data,
char *node = g_strdup_printf("%s:%d", address->name, address->device_id);
signal_buffer *buffer = signal_buffer_create(key_data, key_len);
signal_buffer *original = g_hash_table_lookup(identity_key_store->identity_key_store, node);
signal_buffer *original = g_hash_table_lookup(identity_key_store->trusted, node);
return original == NULL || signal_buffer_compare(buffer, original) == 0;
return original != NULL && signal_buffer_compare(buffer, original) == 0;
}
int

3
src/omemo/store.h
View File

@@ -3,6 +3,7 @@
#include "config.h"
#define OMEMO_STORE_GROUP_IDENTITY "identity"
#define OMEMO_STORE_GROUP_TRUST "trust"
#define OMEMO_STORE_KEY_DEVICE_ID "device_id"
#define OMEMO_STORE_KEY_REGISTRATION_ID "registration_id"
#define OMEMO_STORE_KEY_IDENTITY_KEY_PUBLIC "identity_key_public"
@@ -12,7 +13,7 @@ typedef struct {
signal_buffer *public;
signal_buffer *private;
uint32_t registration_id;
GHashTable * identity_key_store;
GHashTable *trusted;
} identity_key_store_t;
GHashTable * session_store_new(void);