Validate pubsub subscriptions (#627)

* Check topic before subscribing * Block subscribe to invalid topics
vacp2p · Jan 14, 2022 · 1a97d0a · 1a97d0a
1 parent e72d03b
commit 1a97d0a
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Showing 2 changed files with 8 additions and 1 deletion.
diff --git a/libp2p/protocols/pubsub/pubsub.nim b/libp2p/protocols/pubsub/pubsub.nim
@@ -452,6 +452,11 @@ proc subscribe*(p: PubSub,
   ##               on every received message
   ##
 
+  # Check that this is an allowed topic
+  if p.subscriptionValidator != nil and p.subscriptionValidator(topic) == false:
+    warn "Trying to subscribe to a topic not passing validation!", topic
+    return
+
   p.topics.withValue(topic, handlers) do:
     # Already subscribed, just adding another handler
     handlers[].add(handler)

diff --git a/tests/pubsub/testgossipsub2.nim b/tests/pubsub/testgossipsub2.nim
@@ -147,6 +147,9 @@ suite "GossipSub":
         nodes[1].start(),
     ))
 
+    # We must subscribe before setting the validator
+    nodes[0].subscribe("foobar", handler)
+
     var gossip = GossipSub(nodes[0])
     let invalidDetected = newFuture[void]()
     gossip.subscriptionValidator =
@@ -162,7 +165,6 @@ suite "GossipSub":
 
     await subscribeNodes(nodes)
 
-    nodes[0].subscribe("foobar", handler)
     nodes[1].subscribe("foobar", handler)
 
     await invalidDetected.wait(10.seconds)