diff options
| -rwxr-xr-x | siglog-witness.py | 126 |
1 files changed, 63 insertions, 63 deletions
diff --git a/siglog-witness.py b/siglog-witness.py index 997e2c4..6beb96e 100755 --- a/siglog-witness.py +++ b/siglog-witness.py @@ -148,12 +148,63 @@ class TreeHead: assert(verified_data == data) return True - def timestamp(self): - return int(self._text['timestamp']) - def tree_size(self): - return int(self._text['tree_size']) - def root_hash(self): - return unhexlify(self._text['root_hash']) + def timestamp_valid(self, now): + ts_sec = self.timestamp() + ts_asc = time.ctime(ts_sec) + if ts_sec < now - 12 * 3600: + return (ERR_OK, + "WARNING: Tree head timestamp too old: {} ({})".format(ts_sec, ts_asc)) + if ts_sec > now + 12 * 3600: + return (ERR_OK, + "WARNING: Tree head timestamp too new: {} ({})".format(ts_sec, ts_asc)) + + def history_valid(self, prev): + if self.tree_size() < prev.tree_size(): + return (ERR_TREEHEAD_INVALID, + "ERROR: Log is shrinking: {} < {} ".format(self.tree_size(), + prev.tree_size())) + + if self.timestamp() < prev.timestamp(): + return (ERR_TREEHEAD_INVALID, + "ERROR: Log is time traveling: {} < {} ".format(time.ctime(self.timestamp()), + time.ctime(prev.timestamp()))) + + if self.timestamp() == prev.timestamp() and \ + self.root_hash() == prev.root_hash() and \ + self.tree_size() == prev.tree_size(): + return (ERR_OK, + "INFO: Fetched head of tree of size {} already seen".format(prev.tree_size())) + + if self.root_hash() == prev.root_hash() and \ + self.tree_size() != prev.tree_size(): + return (ERR_TREEHEAD_INVALID, + "ERROR: Tree size has changed but hash has not: " + "{}: {} != {}".format(self.root_hash(), + self.tree_size(), + prev.tree_size())) + + if self.root_hash() != prev.root_hash() and \ + self.tree_size() == prev.tree_size(): + return (ERR_TREEHEAD_INVALID, + "ERROR: Hash has changed but tree size has not: " + "{}: {} != {}".format(self.tree_size(), + self.root_hash(), + prev.root_hash())) + + # Same hash and size but new timestamp is ok. + + proof, err = fetch_consistency_proof(prev.tree_size(), self.tree_size()) + if err: return err + if not consistency_proof_valid(prev, self, proof): + errmsg = "ERROR: failing consistency proof check for {}->{}\n".format(prev.tree_size(), + self.tree_size()) + errmsg += "DEBUG: {}:{}->{}:{}\n {}".format(prev.tree_size(), + prev.root_hash(), + self.tree_size(), + self.root_hash(), + proof.path()) + return ERR_CONSISTENCYPROOF_INVALID, errmsg + class ConsistencyProof(): def __init__(self, consistency_proof_data): @@ -413,65 +464,14 @@ def main(args): new_tree_head, err = fetch_tree_head_and_verify(log_verification_key) if err: return err - if not cur_tree_head.signature_valid(log_verification_key): - return ERR_TREEHEAD_SIGNATURE_INVALID, "ERROR: signature of current tree head invalid" + err = new_tree_head.timestamp_valid(now) + if err: return err - # TODO: move to TreeHead.validate_history() - ts_sec = new_tree_head.timestamp() - ts_asc = time.ctime(ts_sec) - if ts_sec < now - 12 * 3600: - return (ERR_OK, - "WARNING: Tree head timestamp too old: {} ({})".format(ts_sec, ts_asc)) - if ts_sec > now + 12 * 3600: - return (ERR_OK, - "WARNING: Tree head timestamp too new: {} ({})".format(ts_sec, ts_asc)) - - if new_tree_head.tree_size() < cur_tree_head.tree_size(): - return (ERR_TREEHEAD_INVALID, - "ERROR: Log is shrinking: {} < {} ".format(new_tree_head.tree_size(), - cur_tree_head.tree_size())) - - if new_tree_head.timestamp() < cur_tree_head.timestamp(): - return (ERR_TREEHEAD_INVALID, - "ERROR: Log is time traveling: {} < {} ".format(time.ctime(new_tree_head.timestamp()), - time.ctime(cur_tree_head.timestamp()))) - - if new_tree_head.timestamp() == cur_tree_head.timestamp() and \ - new_tree_head.root_hash() == cur_tree_head.root_hash() and \ - new_tree_head.tree_size() == cur_tree_head.tree_size(): - return (ERR_OK, - "INFO: Fetched head of tree of size {} already seen".format(cur_tree_head.tree_size())) - - if new_tree_head.root_hash() == cur_tree_head.root_hash() and \ - new_tree_head.tree_size() != cur_tree_head.tree_size(): - return (ERR_TREEHEAD_INVALID, - "ERROR: Tree size has changed but hash has not: " - "{}: {} != {}".format(new_tree_head.root_hash(), - new_tree_head.tree_size(), - cur_tree_head.tree_size())) - - if new_tree_head.root_hash() != cur_tree_head.root_hash() and \ - new_tree_head.tree_size() == cur_tree_head.tree_size(): - return (ERR_TREEHEAD_INVALID, - "ERROR: Hash has changed but tree size has not: " - "{}: {} != {}".format(new_tree_head.tree_size(), - new_tree_head.root_hash(), - cur_tree_head.root_hash())) - - # Same hash and size, new timestamp is ok. - - proof, err = fetch_consistency_proof(cur_tree_head.tree_size(), new_tree_head.tree_size()) + err = new_tree_head.history_valid(cur_tree_head) if err: return err - if not consistency_proof_valid(cur_tree_head, new_tree_head, proof): - errmsg = "ERROR: failing consistency proof check for {}->{}\n".format(cur_tree_head.tree_size(), - new_tree_head.tree_size()) - errmsg += "DEBUG: {}:{}->{}:{}\n {}".format(cur_tree_head.tree_size(), - cur_tree_head.root_hash(), - new_tree_head.tree_size(), - new_tree_head.root_hash(), - proof.path()) - return ERR_CONSISTENCYPROOF_INVALID, errmsg - # TODO: end move + + if not cur_tree_head.signature_valid(log_verification_key): + return ERR_TREEHEAD_SIGNATURE_INVALID, "ERROR: signature of current tree head invalid" err = sign_send_store_tree_head(signing_key, new_tree_head) if err: return err |