Discovered during the Phase F #2260 rebase (not introduced by it — this is a pre-existing latent bug).

Problem

node/rustchain_p2p_gossip.py::_handle_get_state calls self._signed_content() with 3 positional args (msg_type, node_id, payload), but the function signature has been 5 positional args (msg_type, sender_id, msg_id, ttl, payload) since PR #2274 (2026-04-17) extended signature coverage to msg_id and ttl for the #2272 hardening.

# node/rustchain_p2p_gossip.py (current main, ~line 893):
def _handle_get_state(self, msg: GossipMessage) -> Dict:
    ...
    payload = {"state": state_data}
    content = self._signed_content(MessageType.STATE.value, self.node_id, payload)  # 3-arg, bug
    signature, timestamp = self._sign_message(content)
    ...

vs

# node/rustchain_p2p_gossip.py (~line 441):
@staticmethod
def _signed_content(msg_type: str, sender_id: str, msg_id: str, ttl: int, payload: Dict) -> str:
    return f"{msg_type}:{sender_id}:{msg_id}:{ttl}:{json.dumps(payload, sort_keys=True)}"

Calling the 5-arg function with 3 args raises TypeError: _signed_content() missing 2 required positional arguments: 'msg_id' and 'ttl' the moment any peer sends a GET_STATE message.

Why this hasn't been caught yet

• No unit test exercises the full _handle_get_state path end-to-end.
• The STATE-sync path is covered by the request_full_sync hotfix from PR fix: bind STATE sync sender_id to responder's canonical node_id (Phase 2 regression) #2259, but that code handles the response side on the requester; the responder-side _handle_get_state is the one with the buggy arity.
• Production nodes may be silently raising and swallowing this exception inside the message-handler dispatcher, with the state request appearing to time out on the requester.

Proposed fix (small)

Generate a synthetic msg_id and use a static ttl (e.g. 0 since STATE responses aren't re-forwarded) for the signature:

state_msg_id = hashlib.sha256(
    f"STATE:{self.node_id}:{json.dumps(payload, sort_keys=True)}:{time.time()}".encode()
).hexdigest()[:24]
content = self._signed_content(MessageType.STATE.value, self.node_id, state_msg_id, 0, payload)
signature, timestamp = self._sign_message(content)

Then the response dict should also include msg_id and ttl so the requester's verify_message can reconstruct the signed content.

Bounty tier

Small (10-25 RTC) — straightforward 1-method fix + a regression test asserting _handle_get_state runs without raising and the response verifies under verify_message.

Labels

• bug
• p2p
• security-adjacent (affects attestation sync integrity)