GHSA-84x2-2qv6-qg56: Nervos CKB P2P DoS Attacks

Severity: Critical

CVSS Score: 10

The P2P protocols lack of rate limit. For example, in relay protocol, when a node receives a broadcasted `tx_hashes`, it will mark it in memory to avoid duplicated requests. [code → ](https://github.com/nervosnetwork/ckb/blob/26e4837212c392c3c706a0da7a056131fb060433/sync/src/relayer/transactions_process.rs#L67). It is easy to establish a DoS attach by generating random tx hashes. ### Impact It affects all nodes connected to the P2P network. ### Workarounds Apply rate limit on the data sent to CKB P2P port.