eth/protocols/eth: added td length check (#38)

holiman · Nov 23, 2020 · 914d0e2 · 914d0e2
1 parent 72950e8
commit 914d0e2
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/eth/protocols/eth/handshake.go b/eth/protocols/eth/handshake.go
@@ -95,6 +95,11 @@ func (p *Peer) Handshake(network uint64, td *big.Int, head common.Hash, genesis
 	default:
 		panic(fmt.Sprintf("unsupported eth protocol version: %d", p.version))
 	}
+	// TD at mainnet block #7753254 is 76 bits. If it becomes 100 million times
+	// larger, it will still fit within 100 bits
+	if tdlen := p.td.BitLen(); tdlen > 100 {
+		return fmt.Errorf("too large block TD: bitlen %d", tdlen)
+	}
 	return nil
 }