Add OMEMO session long term storage

src/omemo/omemo.c

@@ -52,6 +52,8 @@ struct omemo_context_t {
     GHashTable *device_ids;
     GString *identity_filename;
     GKeyFile *identity_keyfile;
+    GString *sessions_filename;
+    GKeyFile *sessions_keyfile;
 };
 
 static omemo_context omemo_ctx;
@@ -169,15 +171,18 @@ omemo_on_connect(ProfAccount *account)
 
     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("Error creating directory: %s, %s", omemo_ctx.identity_filename->str, errmsg);
+            log_error("Error creating directory: %s, %s", basedir->str, errmsg);
         } else {
-            log_error("Error creating directory: %s", omemo_ctx.identity_filename->str);
+            log_error("Error creating directory: %s", basedir->str);
         }
     }
 
@@ -208,6 +213,32 @@ omemo_on_connect(ProfAccount *account)
 
         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);
+            }
+        }
+    }
 }
 
 void
@@ -395,6 +426,22 @@ omemo_set_device_list(const char *const jid, GList * device_list)
     free(barejid);
 }
 
+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("Error saving OMEMO 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,
@@ -402,7 +449,14 @@ omemo_start_device_session(const char *const jid, uint32_t device_id,
     const unsigned char *const signature, size_t signature_len,
     const unsigned char *const identity_key_raw, size_t identity_key_len)
 {
-    log_info("Start OMEMO session with %s device %d", jid, device_id);
+    signal_protocol_address address = {
+        .name = strdup(jid),
+        .name_len = strlen(jid),
+        .device_id = device_id,
+    };
+
+    if (!contains_session(&address, omemo_ctx.session_store)) {
+        log_info("Create OMEMO session with %s device %d", jid, device_id);
         session_pre_key_bundle *bundle;
         signal_protocol_address *address;
 
@@ -431,6 +485,7 @@ omemo_start_device_session(const char *const jid, uint32_t device_id,
 
         g_list_free_full(prekeys, (GDestroyNotify)free_omemo_key);
     }
+}
 
 gboolean
 omemo_on_message_send(ProfChatWin *chatwin, const char *const message, gboolean request_receipt)

src/omemo/omemo.h

@@ -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_sessions_keyfile(void);
+void omemo_sessions_keyfile_save(void);
 
 void omemo_start_session(const char *const barejid);
 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, size_t signed_prekey_len, const unsigned char *const signature, size_t signature_len, const unsigned char *const identity_key, size_t identity_key_len);

src/omemo/store.c

@@ -1,6 +1,7 @@
 #include <glib.h>
 #include <signal/signal_protocol.h>
 
+#include "omemo/omemo.h"
 #include "omemo/store.h"
 
 GHashTable *
@@ -90,6 +91,13 @@ store_session(const signal_protocol_address *address, uint8_t *record,
 
     signal_buffer *buffer = signal_buffer_create(record, record_len);
     g_hash_table_insert(device_store, GINT_TO_POINTER(address->device_id), buffer);
+
+
+    char *record_b64 = g_base64_encode(record, record_len);
+    g_key_file_set_string(omemo_sessions_keyfile(), address->name, g_strdup_printf("%d", address->device_id), record_b64);
+
+    omemo_sessions_keyfile_save();
+
     return SG_SUCCESS;
 }