From 89b09d25cb19836b9a2c0703ee1368ec760016cc Mon Sep 17 00:00:00 2001
From: Arni Hod <arnon@starkware.co>
Date: Thu, 13 Jun 2024 11:24:12 +0300
Subject: [PATCH] feat: check that the compiled class hash matches the supplied
 class

---
 crates/gateway/src/errors.rs  | 10 ++++++++--
 crates/gateway/src/gateway.rs | 12 ++++++++++++
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/crates/gateway/src/errors.rs b/crates/gateway/src/errors.rs
index fa3c075d9..9c155a988 100644
--- a/crates/gateway/src/errors.rs
+++ b/crates/gateway/src/errors.rs
@@ -5,6 +5,7 @@ use blockifier::state::errors::StateError;
 use blockifier::transaction::errors::TransactionExecutionError;
 use cairo_vm::types::errors::program_errors::ProgramError;
 use starknet_api::block::BlockNumber;
+use starknet_api::core::CompiledClassHash;
 use starknet_api::transaction::{Resource, ResourceBounds};
 use starknet_api::StarknetApiError;
 use thiserror::Error;
@@ -15,16 +16,21 @@ use tokio::task::JoinError;
 pub enum GatewayError {
     #[error(transparent)]
     CompilationError(#[from] starknet_sierra_compile::compile::CompilationUtilError),
+    #[error(
+        "The supplied compiled class hash {supplied:?} does not match the hash of the Casm class \
+         compiled from the supplied Sierra {hash_result:?}."
+    )]
+    CompiledClassHashMismatch { supplied: CompiledClassHash, hash_result: CompiledClassHash },
     #[error("Internal server error: {0}")]
     InternalServerError(#[from] JoinError),
     #[error("Error sending message: {0}")]
     MessageSendError(String),
     #[error(transparent)]
+    ProgramError(#[from] ProgramError),
+    #[error(transparent)]
     StatefulTransactionValidatorError(#[from] StatefulTransactionValidatorError),
     #[error(transparent)]
     StatelessTransactionValidatorError(#[from] StatelessTransactionValidatorError),
-    #[error(transparent)]
-    ProgramError(#[from] ProgramError),
 }
 
 impl IntoResponse for GatewayError {
diff --git a/crates/gateway/src/gateway.rs b/crates/gateway/src/gateway.rs
index 502456e71..14456c341 100644
--- a/crates/gateway/src/gateway.rs
+++ b/crates/gateway/src/gateway.rs
@@ -8,6 +8,8 @@ use axum::routing::{get, post};
 use axum::{Json, Router};
 use blockifier::execution::contract_class::{ClassInfo, ContractClassV1};
 use blockifier::execution::errors::ContractClassError;
+use blockifier::execution::execution_utils::felt_to_stark_felt;
+use starknet_api::core::CompiledClassHash;
 use starknet_api::external_transaction::{ExternalDeclareTransaction, ExternalTransaction};
 use starknet_api::transaction::TransactionHash;
 use starknet_mempool_types::communication::SharedMempoolClient;
@@ -158,6 +160,16 @@ fn compile_contract_class(declare_tx: &ExternalDeclareTransaction) -> GatewayRes
         }
     };
 
+    // TODO: Handle unwrap.
+    let hash_result =
+        CompiledClassHash(felt_to_stark_felt(&casm_contract_class.compiled_class_hash()));
+    if hash_result != tx.compiled_class_hash {
+        return Err(GatewayError::CompiledClassHashMismatch {
+            supplied: tx.compiled_class_hash,
+            hash_result,
+        });
+    }
+
     // Convert Casm contract class to Starknet contract class directly.
     let blockifier_contract_class = ContractClassV1::try_from(casm_contract_class)?.into();
     let class_info = match ClassInfo::new(