From 7fc654e2269ee4dac5b479430f247237cb97770d Mon Sep 17 00:00:00 2001
From: Arni Hod <arnon@starkware.co>
Date: Tue, 26 Nov 2024 17:15:26 +0200
Subject: [PATCH] chore(batcher): verify block number on propose block

---
 crates/starknet_batcher/src/batcher.rs      | 32 +++++++++++++++++++--
 crates/starknet_batcher/src/batcher_test.rs |  8 +++---
 crates/starknet_batcher_types/src/errors.rs |  2 ++
 3 files changed, 36 insertions(+), 6 deletions(-)

diff --git a/crates/starknet_batcher/src/batcher.rs b/crates/starknet_batcher/src/batcher.rs
index 8a12399602..b2c4f9e2c3 100644
--- a/crates/starknet_batcher/src/batcher.rs
+++ b/crates/starknet_batcher/src/batcher.rs
@@ -120,7 +120,11 @@ impl Batcher {
         propose_block_input: ProposeBlockInput,
     ) -> BatcherResult<()> {
         let active_height = self.active_height.ok_or(BatcherError::NoActiveHeight)?;
-        verify_block_input(active_height, propose_block_input.retrospective_block_hash)?;
+        verify_block_input(
+            active_height,
+            propose_block_input.block_info.block_number,
+            propose_block_input.retrospective_block_hash,
+        )?;
 
         let proposal_id = propose_block_input.proposal_id;
         let deadline = deadline_as_instant(propose_block_input.deadline)?;
@@ -154,7 +158,11 @@ impl Batcher {
         validate_block_input: ValidateBlockInput,
     ) -> BatcherResult<()> {
         let active_height = self.active_height.ok_or(BatcherError::NoActiveHeight)?;
-        verify_block_input(active_height, validate_block_input.retrospective_block_hash)?;
+        verify_block_input(
+            active_height,
+            validate_block_input.block_info.block_number,
+            validate_block_input.retrospective_block_hash,
+        )?;
 
         let proposal_id = validate_block_input.proposal_id;
         let deadline = deadline_as_instant(validate_block_input.deadline)?;
@@ -413,6 +421,17 @@ pub fn deadline_as_instant(deadline: chrono::DateTime<Utc>) -> BatcherResult<tok
 }
 
 fn verify_block_input(
+    height: BlockNumber,
+    block_number: BlockNumber,
+    retrospective_block_hash: Option<BlockHashAndNumber>,
+) -> BatcherResult<()> {
+    verify_non_empty_retrospective_block_hash(height, retrospective_block_hash)?;
+    verify_block_number(height, block_number)?;
+
+    Ok(())
+}
+
+fn verify_non_empty_retrospective_block_hash(
     height: BlockNumber,
     retrospective_block_hash: Option<BlockHashAndNumber>,
 ) -> BatcherResult<()> {
@@ -421,5 +440,14 @@ fn verify_block_input(
     {
         return Err(BatcherError::MissingRetrospectiveBlockHash);
     }
+
+    Ok(())
+}
+
+fn verify_block_number(height: BlockNumber, block_number: BlockNumber) -> BatcherResult<()> {
+    if block_number != height {
+        return Err(BatcherError::InvalidBlockNumber { active_height: height, block_number });
+    }
+
     Ok(())
 }
diff --git a/crates/starknet_batcher/src/batcher_test.rs b/crates/starknet_batcher/src/batcher_test.rs
index b8f670a076..f90f384f5d 100644
--- a/crates/starknet_batcher/src/batcher_test.rs
+++ b/crates/starknet_batcher/src/batcher_test.rs
@@ -10,7 +10,7 @@ use futures::FutureExt;
 use mockall::automock;
 use mockall::predicate::{always, eq};
 use rstest::{fixture, rstest};
-use starknet_api::block::{BlockHashAndNumber, BlockNumber};
+use starknet_api::block::{BlockHashAndNumber, BlockInfo, BlockNumber};
 use starknet_api::core::{ContractAddress, Nonce, StateDiffCommitment};
 use starknet_api::executable_transaction::Transaction;
 use starknet_api::hash::PoseidonHash;
@@ -231,7 +231,7 @@ async fn validate_block_full_flow() {
         proposal_id: PROPOSAL_ID,
         deadline: deadline(),
         retrospective_block_hash: None,
-        block_info: Default::default(),
+        block_info: BlockInfo { block_number: INITIAL_HEIGHT, ..Default::default() },
     };
     batcher.validate_block(validate_block_input).await.unwrap();
 
@@ -350,7 +350,7 @@ async fn send_finish_to_an_invalid_proposal() {
         proposal_id: PROPOSAL_ID,
         deadline: deadline(),
         retrospective_block_hash: None,
-        block_info: Default::default(),
+        block_info: BlockInfo { block_number: INITIAL_HEIGHT, ..Default::default() },
     };
     batcher.validate_block(validate_block_input).await.unwrap();
 
@@ -383,7 +383,7 @@ async fn propose_block_full_flow() {
             proposal_id: PROPOSAL_ID,
             retrospective_block_hash: None,
             deadline: chrono::Utc::now() + chrono::Duration::seconds(1),
-            block_info: Default::default(),
+            block_info: BlockInfo { block_number: INITIAL_HEIGHT, ..Default::default() },
         })
         .await
         .unwrap();
diff --git a/crates/starknet_batcher_types/src/errors.rs b/crates/starknet_batcher_types/src/errors.rs
index a3a028a815..b2fc3e5968 100644
--- a/crates/starknet_batcher_types/src/errors.rs
+++ b/crates/starknet_batcher_types/src/errors.rs
@@ -20,6 +20,8 @@ pub enum BatcherError {
     HeightInProgress,
     #[error("Internal server error.")]
     InternalError,
+    #[error("Invalid block number. The active height is {active_height}, got {block_number}.")]
+    InvalidBlockNumber { active_height: BlockNumber, block_number: BlockNumber },
     #[error("Missing retrospective block hash.")]
     MissingRetrospectiveBlockHash,
     #[error("Attempt to start proposal with no active height.")]