Small protocol change for more replay attack prevention.

see the changes to Prevent_Tracking.txt

4 files changed, 76 insertions, 43 deletions

diff --git a/toxcore/onion_announce.c b/toxcore/onion_announce.c
index 3e4f7e0a..8150974b 100644
--- a/toxcore/onion_announce.c
+++ b/toxcore/onion_announce.c
@@ -29,7 +29,7 @@
 
 #define PING_ID_TIMEOUT 20
 
-#define ANNOUNCE_REQUEST_SIZE (1 + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + ONION_PING_ID_SIZE + crypto_box_PUBLICKEYBYTES + ONION_ANNOUNCE_SENDBACK_DATA_LENGTH + crypto_box_MACBYTES)
+#define ANNOUNCE_REQUEST_SIZE (1 + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + ONION_PING_ID_SIZE + crypto_box_PUBLICKEYBYTES + crypto_box_PUBLICKEYBYTES + ONION_ANNOUNCE_SENDBACK_DATA_LENGTH + crypto_box_MACBYTES)
 #define ANNOUNCE_REQUEST_SIZE_RECV (ANNOUNCE_REQUEST_SIZE + ONION_RETURN_3)
 
 #define DATA_REQUEST_MIN_SIZE (1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + crypto_box_MACBYTES)
@@ -43,6 +43,7 @@
  * public_key and secret_key is the kepair which will be used to encrypt the request.
  * ping_id is the ping id that will be sent in the request.
  * client_id is the client id of the node we are searching for.
+ * data_public_key is the public key we want others to encrypt their data packets with.
  * sendback_data is the data of ONION_ANNOUNCE_SENDBACK_DATA_LENGTH length that we expect to
  * receive back in the response.
  *
@@ -50,12 +51,14 @@
  * return 0 on success.
  */
 int send_announce_request(DHT *dht, Node_format *nodes, uint8_t *public_key, uint8_t *secret_key, uint8_t *ping_id,
-                          uint8_t *client_id, uint8_t *sendback_data)
+                          uint8_t *client_id, uint8_t *data_public_key, uint8_t *sendback_data)
 {
-    uint8_t plain[ONION_PING_ID_SIZE + crypto_box_PUBLICKEYBYTES + ONION_ANNOUNCE_SENDBACK_DATA_LENGTH];
+    uint8_t plain[ONION_PING_ID_SIZE + crypto_box_PUBLICKEYBYTES + crypto_box_PUBLICKEYBYTES + ONION_ANNOUNCE_SENDBACK_DATA_LENGTH];
     memcpy(plain, ping_id, ONION_PING_ID_SIZE);
     memcpy(plain + ONION_PING_ID_SIZE, client_id, crypto_box_PUBLICKEYBYTES);
-    memcpy(plain + ONION_PING_ID_SIZE + crypto_box_PUBLICKEYBYTES, sendback_data, ONION_ANNOUNCE_SENDBACK_DATA_LENGTH);
+    memcpy(plain + ONION_PING_ID_SIZE + crypto_box_PUBLICKEYBYTES, data_public_key, crypto_box_PUBLICKEYBYTES);
+    memcpy(plain + ONION_PING_ID_SIZE + crypto_box_PUBLICKEYBYTES + crypto_box_PUBLICKEYBYTES, sendback_data,
+           ONION_ANNOUNCE_SENDBACK_DATA_LENGTH);
     uint8_t packet[ANNOUNCE_REQUEST_SIZE];
     packet[0] = NET_PACKET_ANNOUNCE_REQUEST;
     new_nonce(packet + 1);
@@ -78,12 +81,15 @@ int send_announce_request(DHT *dht, Node_format *nodes, uint8_t *public_key, uin
  * send the packet to that person in the form of a response)
  *
  * public_key is the real public key of the node which we want to send the data of length length to.
+ * encrypt_public_key is the public key used to encrypt the data packet.
+ *
  * nonce is the nonce to encrypt this packet with
  *
  * return -1 on failure.
  * return 0 on success.
  */
-int send_data_request(DHT *dht, Node_format *nodes, uint8_t *public_key, uint8_t *nonce, uint8_t *data, uint16_t length)
+int send_data_request(DHT *dht, Node_format *nodes, uint8_t *public_key, uint8_t *encrypt_public_key, uint8_t *nonce,
+                      uint8_t *data, uint16_t length)
 {
     uint8_t packet[DATA_REQUEST_MIN_SIZE + length];
     packet[0] = NET_PACKET_ONION_DATA_REQUEST;
@@ -96,7 +102,7 @@ int send_data_request(DHT *dht, Node_format *nodes, uint8_t *public_key, uint8_t
 
     memcpy(packet + 1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES, random_public_key, crypto_box_PUBLICKEYBYTES);
 
-    int len = encrypt_data(public_key, random_secret_key, packet + 1 + crypto_box_PUBLICKEYBYTES,
+    int len = encrypt_data(encrypt_public_key, random_secret_key, packet + 1 + crypto_box_PUBLICKEYBYTES,
                            data, length, packet + 1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES);
 
     if (1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + (uint32_t)len != sizeof(packet))
@@ -167,10 +173,11 @@ static int cmp_entry(const void *a, const void *b)
 
 /* add entry to entries list
  *
- * return 0 if failure
- * return 1 if added
+ * return -1 if failure
+ * return position if added
  */
-static int add_to_entries(Onion_Announce *onion_a, IP_Port ret_ip_port, uint8_t *public_key, uint8_t *ret)
+static int add_to_entries(Onion_Announce *onion_a, IP_Port ret_ip_port, uint8_t *public_key, uint8_t *data_public_key,
+                          uint8_t *ret)
 {
 
     int pos = in_entries(onion_a, public_key);
@@ -190,16 +197,17 @@ static int add_to_entries(Onion_Announce *onion_a, IP_Port ret_ip_port, uint8_t
     }
 
     if (pos == -1)
-        return 0;
+        return -1;
 
     memcpy(onion_a->entries[pos].public_key, public_key, crypto_box_PUBLICKEYBYTES);
     onion_a->entries[pos].ret_ip_port = ret_ip_port;
     memcpy(onion_a->entries[pos].ret, ret, ONION_RETURN_3);
+    memcpy(onion_a->entries[pos].data_public_key, data_public_key, crypto_box_PUBLICKEYBYTES);
     onion_a->entries[pos].time = unix_time();
 
     memcpy(cmp_public_key, onion_a->dht->self_public_key, crypto_box_PUBLICKEYBYTES);
     qsort(onion_a->entries, ONION_ANNOUNCE_MAX_ENTRIES, sizeof(Onion_Announce_Entry), cmp_entry);
-    return 1;
+    return pos;
 }
 
 static int handle_announce_request(void *object, IP_Port source, uint8_t *packet, uint32_t length)
@@ -209,10 +217,11 @@ static int handle_announce_request(void *object, IP_Port source, uint8_t *packet
     if (length != ANNOUNCE_REQUEST_SIZE_RECV)
         return 1;
 
-    uint8_t plain[ONION_PING_ID_SIZE + crypto_box_PUBLICKEYBYTES + ONION_ANNOUNCE_SENDBACK_DATA_LENGTH];
+    uint8_t plain[ONION_PING_ID_SIZE + crypto_box_PUBLICKEYBYTES + crypto_box_PUBLICKEYBYTES + ONION_ANNOUNCE_SENDBACK_DATA_LENGTH];
     int len = decrypt_data(packet + 1 + crypto_box_NONCEBYTES, onion_a->dht->self_secret_key, packet + 1,
                            packet + 1 + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES,
-                           ONION_PING_ID_SIZE + crypto_box_PUBLICKEYBYTES + ONION_ANNOUNCE_SENDBACK_DATA_LENGTH + crypto_box_MACBYTES, plain);
+                           ONION_PING_ID_SIZE + crypto_box_PUBLICKEYBYTES + crypto_box_PUBLICKEYBYTES + ONION_ANNOUNCE_SENDBACK_DATA_LENGTH +
+                           crypto_box_MACBYTES, plain);
 
     if ((uint32_t)len != sizeof(plain))
         return 1;
@@ -223,13 +232,14 @@ static int handle_announce_request(void *object, IP_Port source, uint8_t *packet
     uint8_t ping_id2[ONION_PING_ID_SIZE];
     generate_ping_id(onion_a, unix_time() + PING_ID_TIMEOUT, packet + 1 + crypto_box_NONCEBYTES, source, ping_id2);
 
-    int stored = 0;
+    int index = -1;
 
     if (memcmp(ping_id1, plain, ONION_PING_ID_SIZE) == 0 || memcmp(ping_id2, plain, ONION_PING_ID_SIZE) == 0) {
-        stored = add_to_entries(onion_a, source, packet + 1 + crypto_box_NONCEBYTES,
-                                packet + (ANNOUNCE_REQUEST_SIZE_RECV - ONION_RETURN_3));
+        index = add_to_entries(onion_a, source, packet + 1 + crypto_box_NONCEBYTES,
+                               plain + ONION_PING_ID_SIZE + crypto_box_PUBLICKEYBYTES,
+                               packet + (ANNOUNCE_REQUEST_SIZE_RECV - ONION_RETURN_3));
     } else {
-        stored = (in_entries(onion_a, plain + ONION_PING_ID_SIZE) != -1);
+        index = in_entries(onion_a, plain + ONION_PING_ID_SIZE);
     }
 
     /*Respond with a announce response packet*/
@@ -245,24 +255,29 @@ static int handle_announce_request(void *object, IP_Port source, uint8_t *packet
     uint8_t nonce[crypto_box_NONCEBYTES];
     new_nonce(nonce);
 
-    uint8_t pl[ONION_PING_ID_SIZE + sizeof(nodes_list)] = {0};
+    uint8_t pl[1 + ONION_PING_ID_SIZE + sizeof(nodes_list)];
 
-    if (!stored) {
-        memcpy(pl, ping_id2, ONION_PING_ID_SIZE);
+    if (index == -1) {
+        pl[0] = 0;
+        memcpy(pl + 1, ping_id2, ONION_PING_ID_SIZE);
+    } else {
+        pl[0] = 1;
+        memcpy(pl + 1, onion_a->entries[index].data_public_key, crypto_box_PUBLICKEYBYTES);
     }
 
-    memcpy(pl + ONION_PING_ID_SIZE, nodes_list, num_nodes * sizeof(Node_format));
+    memcpy(pl + 1 + ONION_PING_ID_SIZE, nodes_list, num_nodes * sizeof(Node_format));
 
     uint8_t data[ONION_ANNOUNCE_RESPONSE_MAX_SIZE];
     len = encrypt_data(packet + 1 + crypto_box_NONCEBYTES, onion_a->dht->self_secret_key, nonce, pl,
-                       ONION_PING_ID_SIZE + num_nodes * sizeof(Node_format),
+                       1 + ONION_PING_ID_SIZE + num_nodes * sizeof(Node_format),
                        data + 1 + ONION_ANNOUNCE_SENDBACK_DATA_LENGTH + crypto_box_NONCEBYTES);
 
-    if ((uint32_t)len != ONION_PING_ID_SIZE + num_nodes * sizeof(Node_format) + crypto_box_MACBYTES)
+    if ((uint32_t)len != 1 + ONION_PING_ID_SIZE + num_nodes * sizeof(Node_format) + crypto_box_MACBYTES)
         return 1;
 
     data[0] = NET_PACKET_ANNOUNCE_RESPONSE;
-    memcpy(data + 1, plain + ONION_PING_ID_SIZE + crypto_box_PUBLICKEYBYTES, ONION_ANNOUNCE_SENDBACK_DATA_LENGTH);
+    memcpy(data + 1, plain + ONION_PING_ID_SIZE + crypto_box_PUBLICKEYBYTES + crypto_box_PUBLICKEYBYTES,
+           ONION_ANNOUNCE_SENDBACK_DATA_LENGTH);
     memcpy(data + 1 + ONION_ANNOUNCE_SENDBACK_DATA_LENGTH, nonce, crypto_box_NONCEBYTES);
 
     if (send_onion_response(onion_a->net, source, data,
diff --git a/toxcore/onion_announce.h b/toxcore/onion_announce.h
index 01cd7243..27b25bd4 100644
--- a/toxcore/onion_announce.h
+++ b/toxcore/onion_announce.h
@@ -31,15 +31,20 @@
 
 #define ONION_ANNOUNCE_SENDBACK_DATA_LENGTH (crypto_secretbox_NONCEBYTES + sizeof(uint32_t) + sizeof(uint64_t) + crypto_box_PUBLICKEYBYTES + sizeof(IP_Port) + crypto_secretbox_MACBYTES)
 
-#define ONION_ANNOUNCE_RESPONSE_MIN_SIZE (1 + ONION_ANNOUNCE_SENDBACK_DATA_LENGTH + crypto_box_NONCEBYTES + ONION_PING_ID_SIZE + crypto_box_MACBYTES)
+#define ONION_ANNOUNCE_RESPONSE_MIN_SIZE (1 + ONION_ANNOUNCE_SENDBACK_DATA_LENGTH + crypto_box_NONCEBYTES + 1 + ONION_PING_ID_SIZE + crypto_box_MACBYTES)
 #define ONION_ANNOUNCE_RESPONSE_MAX_SIZE (ONION_ANNOUNCE_RESPONSE_MIN_SIZE + sizeof(Node_format)*MAX_SENT_NODES)
 
 #define ONION_DATA_RESPONSE_MIN_SIZE (1 + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + crypto_box_MACBYTES)
 
+#if ONION_PING_ID_SIZE != crypto_box_PUBLICKEYBYTES
+#error announce response packets assume that ONION_PING_ID_SIZE is equal to crypto_box_PUBLICKEYBYTES
+#endif
+
 typedef struct {
     uint8_t public_key[crypto_box_PUBLICKEYBYTES];
     IP_Port ret_ip_port;
     uint8_t ret[ONION_RETURN_3];
+    uint8_t data_public_key[crypto_box_PUBLICKEYBYTES];
     uint64_t time;
 } Onion_Announce_Entry;
 
@@ -59,6 +64,7 @@ typedef struct {
  * public_key and secret_key is the kepair which will be used to encrypt the request.
  * ping_id is the ping id that will be sent in the request.
  * client_id is the client id of the node we are searching for.
+ * data_public_key is the public key we want others to encrypt their data packets with.
  * sendback_data is the data of ONION_ANNOUNCE_SENDBACK_DATA_LENGTH length that we expect to
  * receive back in the response.
  *
@@ -66,7 +72,7 @@ typedef struct {
  * return 0 on success.
  */
 int send_announce_request(DHT *dht, Node_format *nodes, uint8_t *public_key, uint8_t *secret_key, uint8_t *ping_id,
-                          uint8_t *client_id, uint8_t *sendback_data);
+                          uint8_t *client_id, uint8_t *data_public_key, uint8_t *sendback_data);
 
 /* Create and send an onion data request packet.
  *
@@ -75,13 +81,15 @@ int send_announce_request(DHT *dht, Node_format *nodes, uint8_t *public_key, uin
  * send the packet to that person in the form of a response)
  *
  * public_key is the real public key of the node which we want to send the data of length length to.
+ * encrypt_public_key is the public key used to encrypt the data packet.
+ *
  * nonce is the nonce to encrypt this packet with
  *
  * return -1 on failure.
  * return 0 on success.
  */
-int send_data_request(DHT *dht, Node_format *nodes, uint8_t *public_key, uint8_t *nonce, uint8_t *data,
-                      uint16_t length);
+int send_data_request(DHT *dht, Node_format *nodes, uint8_t *public_key, uint8_t *encrypt_public_key, uint8_t *nonce,
+                      uint8_t *data, uint16_t length);
 
 
 Onion_Announce *new_onion_announce(DHT *dht);
diff --git a/toxcore/onion_client.c b/toxcore/onion_client.c
index e50679e5..06f64929 100644
--- a/toxcore/onion_client.c
+++ b/toxcore/onion_client.c
@@ -30,7 +30,6 @@
 
 #define ANNOUNCE_TIMEOUT 10
 
-static uint8_t zero_ping[ONION_PING_ID_SIZE];
 
 /* Creates a sendback for use in an announce request.
  *
@@ -126,11 +125,11 @@ static int client_send_announce_request(Onion_Client *onion_c, uint32_t num, IP_
     if (num == 0) {
         return send_announce_request(onion_c->dht, nodes, onion_c->dht->c->self_public_key,
                                      onion_c->dht->c->self_secret_key, ping_id,
-                                     onion_c->dht->c->self_public_key, sendback);
+                                     onion_c->dht->c->self_public_key, onion_c->temp_public_key, sendback);
     } else {
         return send_announce_request(onion_c->dht, nodes, onion_c->friends_list[num - 1].temp_public_key,
                                      onion_c->friends_list[num - 1].temp_secret_key, ping_id,
-                                     onion_c->friends_list[num - 1].real_client_id, sendback);
+                                     onion_c->friends_list[num - 1].real_client_id, zero_ping_id, sendback);
     }
 }
 
@@ -164,7 +163,7 @@ static int cmp_entry(const void *a, const void *b)
 }
 
 static int client_add_to_list(Onion_Client *onion_c, uint32_t num, uint8_t *public_key, IP_Port ip_port,
-                              uint8_t *ping_id)
+                              uint8_t is_stored, uint8_t *pingid_or_key)
 {
     if (num > onion_c->num_friends)
         return -1;
@@ -204,7 +203,14 @@ static int client_add_to_list(Onion_Client *onion_c, uint32_t num, uint8_t *publ
 
     memcpy(list_nodes[index].client_id, public_key, CLIENT_ID_SIZE);
     list_nodes[index].ip_port = ip_port;
-    memcpy(list_nodes[index].ping_id, ping_id, ONION_PING_ID_SIZE);
+
+    if (is_stored) {
+        memcpy(list_nodes[index].data_public_key, pingid_or_key, crypto_box_PUBLICKEYBYTES);
+    } else {
+        memcpy(list_nodes[index].ping_id, pingid_or_key, ONION_PING_ID_SIZE);
+    }
+
+    list_nodes[index].is_stored = is_stored;
     list_nodes[index].timestamp = unix_time();
     list_nodes[index].last_pinged = 0;
     return 0;
@@ -276,7 +282,7 @@ static int handle_announce_response(void *object, IP_Port source, uint8_t *packe
     if (num > onion_c->num_friends)
         return 1;
 
-    uint8_t plain[ONION_PING_ID_SIZE + num_nodes * sizeof(Node_format)];
+    uint8_t plain[1 + ONION_PING_ID_SIZE + num_nodes * sizeof(Node_format)];
     int len = -1;
 
     if (num == 0) {
@@ -297,10 +303,10 @@ static int handle_announce_response(void *object, IP_Port source, uint8_t *packe
         return 1;
 
 
-    if (client_add_to_list(onion_c, num, public_key, ip_port, plain) == -1)
+    if (client_add_to_list(onion_c, num, public_key, ip_port, plain[0], plain + 1) == -1)
         return 1;
 
-    if (client_ping_nodes(onion_c, num, (Node_format *)plain + ONION_PING_ID_SIZE, num_nodes, source) == -1)
+    if (client_ping_nodes(onion_c, num, (Node_format *)plain + 1 + ONION_PING_ID_SIZE, num_nodes, source) == -1)
         return 1;
 
     return 0;
@@ -319,7 +325,7 @@ static int handle_data_response(void *object, IP_Port source, uint8_t *packet, u
         return 1;
 
     uint8_t temp_plain[length - ONION_DATA_RESPONSE_MIN_SIZE];
-    int len = decrypt_data(packet + 1 + crypto_box_NONCEBYTES, onion_c->dht->c->self_secret_key, packet + 1,
+    int len = decrypt_data(packet + 1 + crypto_box_NONCEBYTES, onion_c->temp_secret_key, packet + 1,
                            packet + 1 + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES,
                            length - (1 + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES), temp_plain);
 
@@ -391,7 +397,6 @@ static int handle_fakeid_announce(void *object, uint8_t *source_pubkey, uint8_t
         DHT_getnodes(onion_c->dht, &nodes[i].ip_port, nodes[i].client_id, onion_c->friends_list[friend_num].fake_client_id);
     }
 
-    //TODO replay protection
     return 0;
 }
 /* Send data of length length to friendnum.
@@ -431,7 +436,7 @@ int send_onion_data(Onion_Client *onion_c, int friend_num, uint8_t *data, uint32
         if (is_timeout(list_nodes[i].timestamp, ONION_NODE_TIMEOUT))
             continue;
 
-        if (memcmp(list_nodes[i].ping_id, zero_ping, ONION_PING_ID_SIZE) == 0) {
+        if (list_nodes[i].is_stored) {
             Node_format nodes[4];
 
             if (random_path(onion_c, nodes) == -1)
@@ -440,8 +445,8 @@ int send_onion_data(Onion_Client *onion_c, int friend_num, uint8_t *data, uint32
             memcpy(nodes[3].client_id, list_nodes[i].client_id, crypto_box_PUBLICKEYBYTES);
             nodes[3].ip_port = list_nodes[i].ip_port;
 
-            if (send_data_request(onion_c->dht, nodes, onion_c->friends_list[friend_num].real_client_id, nonce, packet,
-                                  sizeof(packet)) == 0)
+            if (send_data_request(onion_c->dht, nodes, onion_c->friends_list[friend_num].real_client_id,
+                                  list_nodes[i].data_public_key, nonce, packet, sizeof(packet)) == 0)
                 ++good;
         }
     }
@@ -697,7 +702,7 @@ static void do_announce(Onion_Client *onion_c)
         ++count;
         uint32_t interval = ANNOUNCE_INTERVAL_NOT_ANNOUNCED;
 
-        if (memcmp(list_nodes[i].ping_id, zero_ping, ONION_PING_ID_SIZE) == 0) {
+        if (list_nodes[i].is_stored) {
             interval = ANNOUNCE_INTERVAL_ANNOUNCED;
         }
 
@@ -748,7 +753,7 @@ Onion_Client *new_onion_client(DHT *dht)
     onion_c->dht = dht;
     onion_c->net = dht->c->lossless_udp->net;
     new_symmetric_key(onion_c->secret_symmetric_key);
-
+    crypto_box_keypair(onion_c->temp_public_key, onion_c->temp_secret_key);
     networking_registerhandler(onion_c->net, NET_PACKET_ANNOUNCE_RESPONSE, &handle_announce_response, onion_c);
     networking_registerhandler(onion_c->net, NET_PACKET_ONION_DATA_RESPONSE, &handle_data_response, onion_c);
     oniondata_registerhandler(onion_c, FAKEID_DATA_ID, &handle_fakeid_announce, onion_c);
diff --git a/toxcore/onion_client.h b/toxcore/onion_client.h
index 56adc9ee..afc29f77 100644
--- a/toxcore/onion_client.h
+++ b/toxcore/onion_client.h
@@ -36,6 +36,9 @@ typedef struct {
     uint8_t     client_id[CLIENT_ID_SIZE];
     IP_Port     ip_port;
     uint8_t     ping_id[ONION_PING_ID_SIZE];
+    uint8_t     data_public_key[crypto_box_PUBLICKEYBYTES];
+    uint8_t     is_stored;
+
     uint64_t    timestamp;
 
     uint64_t    last_pinged;
@@ -70,6 +73,8 @@ typedef struct {
     uint8_t secret_symmetric_key[crypto_secretbox_KEYBYTES];
     uint64_t last_run;
 
+    uint8_t temp_public_key[crypto_box_PUBLICKEYBYTES];
+    uint8_t temp_secret_key[crypto_box_SECRETKEYBYTES];
     struct {
         oniondata_handler_callback function;
         void *object;