finalizing state_transition (#792)

beacon_chain/block_pool.nim

@@ -373,7 +373,6 @@ proc add*(
     # TODO if the block is from the future, we should not be resolving it (yet),
     #      but maybe we should use it as a hint that our clock is wrong?
     updateStateData(pool, pool.tmpState, BlockSlot(blck: parent, slot: blck.slot - 1))
-
     if not state_transition(pool.tmpState.data, signedBlock, {}):
       # TODO find a better way to log all this block data
       notice "Invalid block",
@@ -382,7 +381,6 @@ proc add*(
         cat = "filtering"
 
       return
-
     # Careful, tmpState.data has been updated but not blck - we need to create
     # the BlockRef first!
     pool.tmpState.blck = pool.addResolvedBlock(

beacon_chain/spec/helpers.nim

@@ -151,7 +151,7 @@ func compute_signing_root*(ssz_object: auto, domain: Domain): Eth2Digest =
   # object-domain tree.
   let domain_wrapped_object = SigningRoot(
     object_root: hash_tree_root(ssz_object),
-    domain: domain
+    domain: bytes_to_int(domain)
   )
   hash_tree_root(domain_wrapped_object)
 

beacon_chain/state_transition.nim

@@ -31,9 +31,9 @@
 # now.
 
 import
-  collections/sets, chronicles, sets,
+  collections/sets, chronicles, sets, options,
   ./extras, ./ssz, metrics,
-  ./spec/[datatypes, digest, helpers, validator],
+  ./spec/[datatypes, crypto, digest, helpers, validator],
   ./spec/[state_transition_block, state_transition_epoch],
   ../nbench/bench_lab
 
@@ -101,6 +101,19 @@ proc process_slots*(state: var BeaconState, slot: Slot) {.nbench.}=
     if is_epoch_transition:
       beacon_current_validators.set(get_epoch_validator_count(state))
 
+#https://github.com/ethereum/eth2.0-specs/blob/v0.10.1/specs/phase0/beacon-chain.md#verify_block_signature
+proc verify_block_signature*(state: var BeaconState, signedBlock: SignedBeaconBlock, stateCache: var StateCache): bool {.nbench.} =
+  let proposer = state.validators[get_beacon_proposer_index(state, stateCache).get]
+  let domain = get_domain(state, DOMAIN_BEACON_PROPOSER, compute_epoch_at_slot(signedBlock.message.slot)) 
+  # TODO This will need to be changed for: 
+  # ```
+  # let signing_root = compute_signing_root(signedBlock.message,domain)
+  # return bls_verify(proposer.pubKey, signing_root.data, signedBlock.signature, domain)
+  # ```
+  # when https://github.com/status-im/nim-beacon-chain/pull/780 is merged
+  return bls_verify(proposer.pubKey, hash_tree_root(signedBlock.message).data, signedBlock.signature, domain)
+  
+
 # https://github.com/ethereum/eth2.0-specs/blob/v0.9.4/specs/core/0_beacon-chain.md#beacon-chain-state-transition-function
 proc verifyStateRoot(state: BeaconState, blck: BeaconBlock): bool =
   # This is inlined in state_transition(...) in spec.
@@ -157,6 +170,10 @@ proc state_transition*(
   #      https://github.com/ethereum/eth2.0-specs/issues/293
   var per_epoch_cache = get_empty_per_epoch_cache()
 
+  if skipBLSValidation notin flags and not verify_block_signature(state, signedBlock, per_epoch_cache):
+    state = old_state
+    return false
+
   if processBlock(state, signedBlock.message, flags, per_epoch_cache):
     # This is a bit awkward - at the end of processing we verify that the
     # state we arrive at is what the block producer thought it would be -
@@ -224,6 +241,10 @@ proc state_transition*(
   process_slots(state, signedBlock.message.slot)
   var per_epoch_cache = get_empty_per_epoch_cache()
 
+  if skipBLSValidation notin flags and not verify_block_signature(state.data, signedBlock, per_epoch_cache):
+    state = old_state
+    return false
+
   if processBlock(state.data, signedBlock.message, flags, per_epoch_cache):
     if skipStateRootValidation in flags or verifyStateRoot(state.data, signedBlock.message):
       # State root is what it should be - we're done!