Validate peering key on incoming sync offer

LXMF/LXMPeer.py

@@ -22,7 +22,9 @@ class LXMPeer:
 
     ERROR_NO_IDENTITY     = 0xf0
     ERROR_NO_ACCESS       = 0xf1
-    ERROR_THROTTLED       = 0xf2
+    ERROR_INVALID_KEY     = 0xf3
+    ERROR_INVALID_DATA    = 0xf4
+    ERROR_THROTTLED       = 0xf5
     ERROR_TIMEOUT         = 0xfe
 
     STRATEGY_LAZY         = 0x01
@@ -369,9 +371,11 @@ class LXMPeer:
                                     cumulative_size += lxm_transfer_size
                                     unhandled_ids.append(transient_id)
 
+                                offer = [self.peering_key[0], unhandled_ids]
+
                                 RNS.log(f"Offering {len(unhandled_ids)} messages to peer {RNS.prettyhexrep(self.destination.hash)} ({RNS.prettysize(len(msgpack.packb(unhandled_ids)))})", RNS.LOG_VERBOSE)
                                 self.last_offer = unhandled_ids
-                                self.link.request(LXMPeer.OFFER_REQUEST_PATH, unhandled_ids, response_callback=self.offer_response, failed_callback=self.request_failed)
+                                self.link.request(LXMPeer.OFFER_REQUEST_PATH, offer, response_callback=self.offer_response, failed_callback=self.request_failed)
                                 self.state = LXMPeer.REQUEST_SENT
 
                 else:

LXMF/LXMRouter.py

@@ -45,8 +45,8 @@ class LXMRouter:
     ROTATION_HEADROOM_PCT = 10
     ROTATION_AR_MAX       = 0.5
 
-    PEERING_COST          = 10
-    MAX_PEERING_COST      = 12
+    PEERING_COST          = 18
+    MAX_PEERING_COST      = 24
     PROPAGATION_COST_MIN  = 13
     PROPAGATION_COST_FLEX = 3
     PROPAGATION_COST      = 16
@@ -2047,21 +2047,30 @@ class LXMRouter:
                     return LXMPeer.ERROR_NO_ACCESS
 
             try:
-                transient_ids = data
-                wanted_ids = []
+                if type(data) != list and len(data) < 2: return LXMPeer.ERROR_INVALID_DATA
 
-                for transient_id in transient_ids:
-                    if not transient_id in self.propagation_entries:
-                        wanted_ids.append(transient_id)
+                peering_id         = self.identity.hash+remote_identity
+                target_cost        = self.peering_cost
+                peering_key        = data[0]
+                transient_ids      = data[1]
+                wanted_ids         = []
 
-                if len(wanted_ids) == 0:
-                    return False
+                ts                 = time.time()
+                peering_key_valid  = LXStamper.validate_peering_key(peering_id, peering_key, target_cost)
+                td                 = time.time() - ts
 
-                elif len(wanted_ids) == len(transient_ids):
-                    return True
+                if not peering_key_valid:
+                    RNS.log(f"Invalid peering key for incoming sync offer", RNS.LOG_DEBUG)
+                    return LXMPeer.ERROR_INVALID_KEY
 
                 else:
-                    return wanted_ids
+                    RNS.log(f"Peering key validated for incoming offer in {RNS.prettytime(td)}", RNS.LOG_DEBUG)
+                    for transient_id in transient_ids:
+                        if not transient_id in self.propagation_entries: wanted_ids.append(transient_id)
+
+                    if len(wanted_ids)   == 0:                  return False
+                    elif len(wanted_ids) == len(transient_ids): return True
+                    else:                                       return wanted_ids
 
             except Exception as e:
                 RNS.log("Error occurred while generating response for sync request, the contained exception was: "+str(e), RNS.LOG_DEBUG)
@@ -2069,9 +2078,6 @@ class LXMRouter:
 
     def propagation_resource_concluded(self, resource):
         if resource.status == RNS.Resource.COMPLETE:
-            # TODO: The peer this was received from should
-            # have the transient id added to its list of
-            # already handled messages.
             try:
                 data = msgpack.unpackb(resource.data.read())
 

LXMF/LXStamper.py

@@ -8,8 +8,8 @@ import itertools
 import multiprocessing
 
 WORKBLOCK_EXPAND_ROUNDS         = 3000
-WORKBLOCK_EXPAND_ROUNDS_PEERING = 20000
 WORKBLOCK_EXPAND_ROUNDS_PN      = 1000
+WORKBLOCK_EXPAND_ROUNDS_PEERING = 25
 STAMP_SIZE                      = RNS.Identity.HASHLENGTH
 PN_VALIDATION_POOL_MIN_SIZE     = 256
 
@@ -45,6 +45,11 @@ def stamp_valid(stamp, target_cost, workblock):
     if int.from_bytes(result, byteorder="big") > target: return False
     else: return True
 
+def validate_peering_key(peering_id, peering_key, target_cost):
+    workblock = stamp_workblock(peering_id, expand_rounds=WORKBLOCK_EXPAND_ROUNDS_PEERING)
+    if not stamp_valid(peering_key, target_cost, workblock): return False
+    else: return True
+
 def validate_pn_stamp(transient_data, target_cost):
     from .LXMessage import LXMessage
     if len(transient_data) <= LXMessage.LXMF_OVERHEAD+STAMP_SIZE: return False, None, None
@@ -348,6 +353,13 @@ def job_android(stamp_cost, workblock, message_id):
 
     return stamp, total_rounds
 
+# def stamp_value_linear(workblock, stamp):
+#     value = 0
+#     bits = 256
+#     material = RNS.Identity.full_hash(workblock+stamp)
+#     s = int.from_bytes(material, byteorder="big")
+#     return s.bit_count()
+
 if __name__ == "__main__":
     import sys
     if len(sys.argv) < 2:
@@ -365,10 +377,12 @@ if __name__ == "__main__":
     message_id = os.urandom(32)
     generate_stamp(message_id, cost)
 
+    RNS.log("", RNS.LOG_DEBUG)
     RNS.log("Testing propagation stamp generation", RNS.LOG_DEBUG)
     message_id = os.urandom(32)
     generate_stamp(message_id, cost, expand_rounds=WORKBLOCK_EXPAND_ROUNDS_PN)
 
+    RNS.log("", RNS.LOG_DEBUG)
     RNS.log("Testing peering key generation", RNS.LOG_DEBUG)
     message_id = os.urandom(32)
     generate_stamp(message_id, cost, expand_rounds=WORKBLOCK_EXPAND_ROUNDS_PEERING)