From 561024eb35497c8f2cc7e4b7d7ebbe607773d655 Mon Sep 17 00:00:00 2001
From: jfreegman <jfreegman@gmail.com>
Date: Sun, 31 May 2020 22:56:56 -0400
Subject: [PATCH] Fix some connection/sync issues

We now make sure that peers without a valid shared state can't accept invite
requests or sync requests. In addition, connected peers no longer accept
announcements
---
 toxcore/group_chats.c | 37 +++++++++++++++++++++++++++++++------
 toxcore/group_chats.h |  7 +++++++
 2 files changed, 38 insertions(+), 6 deletions(-)

diff --git a/toxcore/group_chats.c b/toxcore/group_chats.c
index 8f394121c31..3cc7efb41dc 100644
--- a/toxcore/group_chats.c
+++ b/toxcore/group_chats.c
@@ -1072,8 +1072,9 @@ static int handle_gc_sync_response(Messenger *m, int group_number, int peer_numb
         return -1;
     }
 
-    chat->connection_state = CS_CONNECTED;
-    send_gc_peer_exchange(c, chat, gconn);
+    if (chat->connection_state == CS_CONNECTED) {
+        send_gc_peer_exchange(c, chat, gconn);
+    }
 
     if (c->self_join && chat->time_connected == 0) {
         (*c->self_join)(m, group_number, c->self_join_userdata);
@@ -1134,6 +1135,10 @@ static int handle_gc_sync_request(const Messenger *m, int group_number, int peer
         return -1;
     }
 
+    if (chat->connection_state != CS_CONNECTED) {
+        return -1;
+    }
+
     if (chat->numpeers <= 1) {
         LOGGER_WARNING(m->log, "Got sync request with empty peer list?");
         return -1;
@@ -1377,7 +1382,11 @@ static int handle_gc_invite_response(const Messenger *m, int group_number, GC_Co
         sync_flags = 0xffff;
     }
 
-    return send_gc_sync_request(chat, gconn, sync_flags);
+    if (chat->connection_state != CS_CONNECTED) {
+        return send_gc_sync_request(chat, gconn, sync_flags);
+    }
+
+    return 0;
 }
 
 static int handle_gc_invite_response_reject(Messenger *m, int group_number, const uint8_t *data, uint32_t length)
@@ -1444,6 +1453,10 @@ static int handle_gc_invite_request(Messenger *m, int group_number, uint32_t pee
         return -1;
     }
 
+    if (chat->connection_state != CS_CONNECTED) {
+        return -1;
+    }
+
     GC_Connection *gconn = gcc_get_connection(chat, peer_number);
 
     if (gconn == nullptr) {
@@ -2221,6 +2234,8 @@ static int handle_gc_sanctions_list(Messenger *m, int group_number, uint32_t pee
         }
     }
 
+    chat->connection_state = CS_CONNECTED;
+
     return 0;
 }
 
@@ -4228,7 +4243,11 @@ static int handle_gc_handshake_response(const Messenger *m, int group_number, co
             break;
 
         case HS_PEER_INFO_EXCHANGE:
-            ret = send_gc_peer_exchange(m->group_handler, chat, gconn);
+            if (chat->connection_state != CS_CONNECTED) {
+                ret = -1;
+            } else {
+                ret = send_gc_peer_exchange(m->group_handler, chat, gconn);
+            }
             break;
 
         default:
@@ -5475,7 +5494,7 @@ static int create_new_group(GC_Session *c, const uint8_t *nick, size_t nick_leng
 
     chat->group_number = group_number;
     chat->numpeers = 0;
-    chat->connection_state = CS_CONNECTING;
+    chat->connection_state = CS_CONNECTED;
     chat->net = m->net;
     chat->mono_time = m->mono_time;
     chat->logger = m->log;
@@ -5594,7 +5613,6 @@ int gc_group_load(GC_Session *c, const Saved_Group *save, int group_number)
 
     chat->group_number = group_number;
     chat->numpeers = 0;
-    chat->connection_state = is_active_chat ? CS_CONNECTING : CS_DISCONNECTED;
     chat->join_type = HJ_PRIVATE;
     chat->net = m->net;
     chat->mono_time = m->mono_time;
@@ -5632,6 +5650,8 @@ int gc_group_load(GC_Session *c, const Saved_Group *save, int group_number)
     chat->chat_id_hash = get_chat_id_hash(get_chat_id(chat->chat_public_key));
     chat->self_public_key_hash = get_peer_key_hash(chat->self_public_key);
 
+    chat->connection_state = chat->shared_state.version == 0 ? CS_CONNECTING : CS_CONNECTED;
+
     if (peer_add(m, group_number, nullptr, save->self_public_key) != 0) {
         return -1;
     }
@@ -5654,6 +5674,7 @@ int gc_group_load(GC_Session *c, const Saved_Group *save, int group_number)
     }
 
     if (!is_active_chat) {
+        chat->connection_state = CS_DISCONNECTED;
         chat->save = (Saved_Group *)malloc(sizeof(Saved_Group));
 
         if (chat->save == nullptr) {
@@ -6434,6 +6455,10 @@ int add_peers_from_announces(const GC_Session *gc_session, GC_Chat *chat, GC_Ann
         return -1;
     }
 
+    if (chat->connection_state == CS_CONNECTED && chat->numpeers > 1) {
+        return 0;
+    }
+
     int added_peers = 0;
 
     for (uint8_t i = 0; i < gc_announces_count; ++i) {
diff --git a/toxcore/group_chats.h b/toxcore/group_chats.h
index d345b2f5538..b32a02c1663 100644
--- a/toxcore/group_chats.h
+++ b/toxcore/group_chats.h
@@ -99,9 +99,16 @@ typedef enum Group_Peer_Status {
 } Group_Peer_Status;
 
 typedef enum GC_Conn_State {
+    /* The group index is vacant */
     CS_NONE,
+
+    /* Not connected or attempting to connect to other peers */
     CS_DISCONNECTED,
+
+    /* Attempting to connect to other peers but does not yet have a valid shared state */
     CS_CONNECTING,
+
+    /* Has a valid shared state and is connected or attempting to connect to other peers */
     CS_CONNECTED,
     CS_INVALID,
 } GC_Conn_State;