consensus: reintroduce timestamp checks

See also #1649
See also dusk-network/dips#13

consensus/src/commons.rs

@@ -34,6 +34,7 @@ pub struct RoundUpdate {
     seed: Seed,
     hash: [u8; 32],
     cert: Certificate,
+    timestamp: u64,
 
     pub base_timeouts: TimeoutSet,
 }
@@ -53,6 +54,7 @@ impl RoundUpdate {
             cert: mrb_header.cert,
             hash: mrb_header.hash,
             seed: mrb_header.seed,
+            timestamp: mrb_header.timestamp,
             base_timeouts,
         }
     }
@@ -68,6 +70,10 @@ impl RoundUpdate {
     pub fn cert(&self) -> &Certificate {
         &self.cert
     }
+
+    pub fn timestamp(&self) -> u64 {
+        self.timestamp
+    }
 }
 
 #[derive(Debug, Clone, Copy, Error)]
@@ -100,6 +106,7 @@ pub enum ConsensusError {
     InvalidQuorumType,
     InvalidVote(Vote),
     InvalidMsgIteration(u8),
+    InvalidTimestamp,
     FutureEvent,
     PastEvent,
     NotCommitteeMember,

consensus/src/proposal/handler.rs

@@ -4,7 +4,9 @@
 //
 // Copyright (c) DUSK NETWORK. All rights reserved.
 
-use crate::commons::{ConsensusError, Database, RoundUpdate};
+use crate::commons::{
+    get_current_timestamp, ConsensusError, Database, RoundUpdate,
+};
 use crate::merkle::merkle_root;
 use crate::msg_handler::{HandleMsgOutput, MsgHandler};
 use crate::user::committee::Committee;
@@ -42,11 +44,16 @@ impl<D: Database> MsgHandler for ProposalHandler<D> {
     async fn collect(
         &mut self,
         msg: Message,
-        _ru: &RoundUpdate,
+        ru: &RoundUpdate,
         _committee: &Committee,
     ) -> Result<HandleMsgOutput, ConsensusError> {
         // store candidate block
         let p = Self::unwrap_msg(&msg)?;
+
+        if p.candidate.header().timestamp < ru.timestamp() {
+            return Err(ConsensusError::InvalidTimestamp);
+        }
+
         self.db
             .lock()
             .await
@@ -84,10 +91,17 @@ impl<D: Database> ProposalHandler<D> {
         //  Verify new_block msg signature
         p.verify_signature()?;
 
+        // We only check the consistency of the declared hash.
+        // The actual bound with the tip.block_hash is done by
+        // MsgHandler.is_valid()
         if msg.header.prev_block_hash != p.candidate.header().prev_block_hash {
             return Err(ConsensusError::InvalidBlockHash);
         }
 
+        if p.candidate.header().timestamp > get_current_timestamp() {
+            return Err(ConsensusError::InvalidTimestamp);
+        }
+
         let tx_hashes: Vec<[u8; 32]> =
             p.candidate.txs().iter().map(|t| t.hash()).collect();
         let tx_root = merkle_root(&tx_hashes[..]);