def _pcb_list_to_remove(self, candidates, rev_info):
"""
Calculates the list of PCBs to remove.
Called by _remove_revoked_pcbs.
:param candidates: Candidate PCBs.
:type candidates: List
:param rev_info: The RevocationInfo object.
:type rev_info: RevocationInfo
"""
to_remove = []
processed = set()
for cand in candidates:
if cand.id in processed:
continue
processed.add(cand.id)
if not ConnectedHashTree.verify_epoch(rev_info.p.epoch):
continue
# If the interface on which we received the PCB is
# revoked, then the corresponding pcb needs to be removed.
root_verify = ConnectedHashTree.verify(rev_info,
self._get_ht_root())
if (self.addr.isd_as == rev_info.isd_as()
and cand.pcb.p.ifID == rev_info.p.ifID and root_verify):
to_remove.append(cand.id)
for asm in cand.pcb.iter_asms():
if self._verify_revocation_for_asm(rev_info, asm, False):
to_remove.append(cand.id)
return to_remove
def _verify_revocation_for_asm(self,
rev_info,
as_marking,
verify_all=True):
"""
Verifies a revocation for a given AS marking.
:param rev_info: The RevocationInfo object.
:param as_marking: The ASMarking object.
:param verify_all: If true, verify all PCBMs (including peers),
otherwise only verify the up/down hop.
:return: True, if the revocation successfully revokes an upstream
interface in the AS marking, False otherwise.
"""
if rev_info.isd_as() != as_marking.isd_as():
return False
if not ConnectedHashTree.verify(rev_info, as_marking.p.hashTreeRoot):
return False
for pcbm in as_marking.iter_pcbms():
if rev_info.p.ifID in [
pcbm.hof().ingress_if,
pcbm.hof().egress_if
]:
return True
if not verify_all:
break
return False
def test(self):
# Check that the revocation proof is verifiable in T.
isd_as = ISD_AS("1-11")
if_ids = [23, 35, 120]
initial_seed = b"qwerty"
inst = ConnectedHashTree(isd_as, if_ids, initial_seed, HashType.SHA256)
root = inst.get_root()
# Call
proof = inst.get_proof(120)
# Tests
ntools.eq_(ConnectedHashTree.verify(proof, root), True)
def test_one_timestep(self):
# Check that the revocation proof is verifiable across T and T+1.
# Setup
isd_as = ISD_AS("1-11")
if_ids = [23, 35, 120]
initial_seed = b"qwerty"
inst = ConnectedHashTree(isd_as, if_ids, initial_seed)
root = inst.get_root()
# Call
next_tree = inst.get_next_tree(isd_as, if_ids, b"new!!seed")
inst.update(next_tree)
# Tests
proof = inst.get_proof(35) # if_id = 35.
ntools.eq_(ConnectedHashTree.verify(proof, root), True)
def test_two_timesteps(self):
# Check that the revocation proof is "NOT" verifiable across T and T+2.
# Setup
isd_as = ISD_AS("1-11")
if_ids = [23, 35, 120]
initial_seed = b"qwerty"
inst = ConnectedHashTree(isd_as, if_ids, initial_seed, HashType.SHA256)
root = inst.get_root()
# Call
new_tree = inst.get_next_tree(isd_as, if_ids, b"newseed.@1",
HashType.SHA256)
inst.update(new_tree)
new_tree = inst.get_next_tree(isd_as, if_ids, b"newseed.@2",
HashType.SHA256)
inst.update(new_tree)
# Tests
proof = inst.get_proof(35) # if_id = 35.
ntools.eq_(ConnectedHashTree.verify(proof, root), False)
def _skip_peer(cls, peer_rev, ht_root): # pragma: no cover
if not peer_rev:
return False
return (ConnectedHashTree.verify_epoch(peer_rev.p.epoch)
and ConnectedHashTree.verify(peer_rev, ht_root))
def _skip_peer(peer_rev, ht_root): # pragma: no cover
if not peer_rev:
return False
rev_status = ConnectedHashTree.verify_epoch(peer_rev.p.epoch)
return (rev_status == ConnectedHashTree.EPOCH_OK and
ConnectedHashTree.verify(peer_rev, ht_root))
