takers: ignore makers with more than max_offers_allowed offers

joinmarket/configure.py

@@ -60,6 +60,7 @@ def __getitem__(self, key):
 global_singleton.ordername_list = ['absoffer', 'reloffer']
 global_singleton.commitment_broadcast_list = ['hp2']
 global_singleton.maker_timeout_sec = 60
+global_singleton.max_maker_offers_allowed = 15
 global_singleton.debug_file_lock = threading.Lock()
 global_singleton.debug_file_handle = None
 global_singleton.blacklist_file_lock = threading.Lock()
@@ -131,6 +132,11 @@ def jm_single():
 # responsive. Should be an integer >=2 for privacy, or set to 0 if you
 # want to disallow any reduction from your chosen number of makers.
 minimum_makers = 2
+# For takers: to filter out potentially malicious makers, this is
+# the maximum number of offers a maker is allowed to have. If a
+# makers has more offers, then he will be disregarded as potential
+# counterparty for coinjoins
+max_maker_offers_allowed = 15
 # the fee estimate is based on a projection of how many satoshis
 # per kB are needed to get in one of the next N blocks, N set here
 # as the value of 'tx_fees'. This estimate is high if you set N=2,
@@ -348,6 +354,13 @@ def load_program_config():
         log.info('TIMEOUT/maker_timeout_sec not found in .cfg file, '
                   'using default value')
 
+    try:
+        global_singleton.max_maker_offers_allowed = global_singleton.config.getint(
+            'POLICY', 'max_maker_offers_allowed')
+    except NoOptionError:
+        log.info('POLICY/max_maker_offers_allowed not found in .cfg file, '
+                 'using default value')
+
     # configure the interface to the blockchain on startup
     global_singleton.bc_interface = get_blockchain_interface_instance(
         global_singleton.config)

joinmarket/taker.py

@@ -542,6 +542,7 @@ def __init__(self, msgchan):
         self.msgchan.register_channel_callbacks(
                 self.on_welcome, self.on_set_topic, None, self.on_disconnect,
                 self.on_nick_leave, None)
+        self.banned_makers = []
         self.dblock = threading.Lock()
         con = sqlite3.connect(":memory:", check_same_thread=False)
         con.row_factory = sqlite3.Row
@@ -552,11 +553,16 @@ def __init__(self, msgchan):
 
     def on_order_seen(self, counterparty, oid, ordertype, minsize, maxsize,
                       txfee, cjfee):
+        if counterparty in self.banned_makers:
+            log.debug('Saw offer by blacklisted maker, ignoring: ' + str(counterparty))
+            return
         try:
             self.dblock.acquire(True)
-            if int(oid) < 0 or int(oid) > sys.maxint:
+            if int(oid) < 0 or int(oid) >= jm_single().config.getint("POLICY", "max_maker_offers_allowed"):
                 log.debug(
-                    "Got invalid order ID: " + oid + " from " + counterparty)
+                    "Got invalid order ID: " + oid + " from " + counterparty + ". Adding to blacklist.")
+                self.db.execute("DELETE FROM orderbook WHERE counterparty=?;", (counterparty, ))
+                self.banned_makers.append(counterparty)
                 return
             # delete orders eagerly, so in case a buggy maker sends an
             # invalid offer, we won't accidentally !fill based on the ghost
@@ -582,7 +588,6 @@ def on_order_seen(self, counterparty, oid, ordertype, minsize, maxsize,
                         txfee, counterparty))
                 return
             if int(minsize) > int(maxsize):
-
                 fmt = ("Got minsize bigger than maxsize: {} - {} "
                        "from {}").format
                 log.debug(fmt(minsize, maxsize, counterparty))