fix(SharedMemory): restore cfg memory limit

Author: Lorenzo Feroleto

crates/interpreter/src/instructions/macros.rs

@@ -55,6 +55,12 @@ macro_rules! shared_memory_resize {
         if let Some(new_size) =
             crate::interpreter::next_multiple_of_32($offset.saturating_add($len))
         {
+            #[cfg(feature = "memory_limit")]
+            if $interp.shared_memory.limit_reached(new_size) {
+                $interp.instruction_result = InstructionResult::MemoryLimitOOG;
+                return;
+            }
+
             if new_size > $interp.shared_memory.len() {
                 if crate::USE_GAS {
                     let num_bytes = new_size / 32;

crates/interpreter/src/interpreter/shared_memory.rs

@@ -18,6 +18,9 @@ pub struct SharedMemory {
     checkpoints: Vec<usize>,
     /// How much memory has been used in the current context
     current_len: usize,
+    /// Memory limit. See [`crate::CfgEnv`].
+    #[cfg(feature = "memory_limit")]
+    pub memory_limit: u64,
 }
 
 impl fmt::Debug for SharedMemory {
@@ -45,9 +48,29 @@ impl SharedMemory {
             data: Vec::with_capacity(4 * 1024), // from evmone
             checkpoints: Vec::with_capacity(32),
             current_len: 0,
+            #[cfg(feature = "memory_limit")]
+            memory_limit: u64::MAX,
         }
     }
 
+    /// Allocate memory to be shared between calls, with `memory_limit`
+    /// as upper bound for allocation size.
+    /// Initial capacity is 4KiB which is expanded if needed
+    #[cfg(feature = "memory_limit")]
+    pub fn new_with_memory_limit(memory_limit: u64) -> Self {
+        Self {
+            memory_limit,
+            ..Self::new()
+        }
+    }
+
+    /// Returns true if the `new_size` for the current context memory will
+    /// make the shared buffer length exceed the `memory_limit`
+    #[cfg(feature = "memory_limit")]
+    pub fn limit_reached(&self, new_size: usize) -> bool {
+        (self.last_checkpoint() + new_size) as u64 > self.memory_limit
+    }
+
     /// Prepares the shared memory for a new context
     pub fn new_context_memory(&mut self) {
         let base_offset = self.last_checkpoint();
@@ -221,7 +244,7 @@ impl SharedMemory {
     /// Get the last memory checkpoint
     #[inline(always)]
     fn last_checkpoint(&self) -> usize {
-        *self.checkpoints.last().unwrap_or(&0)
+        self.checkpoints.last().cloned().unwrap_or_default()
     }
 }
 

crates/revm/src/evm_impl.rs

@@ -288,6 +288,9 @@ impl<'a, GSPEC: Spec, DB: Database, const INSPECT: bool> Transact<DB::Error>
 
         let transact_gas_limit = tx_gas_limit - initial_gas_spend;
 
+        #[cfg(feature = "memory_limit")]
+        let mut shared_memory = SharedMemory::new_with_memory_limit(self.data.env.cfg.memory_limit);
+        #[cfg(not(feature = "memory_limit"))]
         let mut shared_memory = SharedMemory::new();
 
         // call inner handling of call/create