added block header sanity check

diff --git a/p2pool/bitcoin/p2p.py b/p2pool/bitcoin/p2p.py
index 9905f69..3b5bf1e 100644 (file)
--- a/p2pool/bitcoin/p2p.py
+++ b/p2pool/bitcoin/p2p.py
@@ -291,6 +291,7 @@ class HeaderWrapper(object):
     
     @classmethod
     def from_header(cls, header):
+        assert bitcoin_data.block_header_type.hash256(header) <= header['target']
         return cls(bitcoin_data.block_header_type.hash256(header), header['previous_block'])
     
     def __init__(self, hash, previous_hash):