[M2] A malicious receiver could prevent the OffRamp from receiving funds from the MerkleRoot

contracts/contracts/ccip/merkle_root/contract.tolk

@@ -32,6 +32,11 @@ fun onInternalMessage(in: InMessage) {
             onMarkState(mutate st, msg);
             st.store();
         }
+        MerkleRoot_Freeze => {
+            val st = lazy MerkleRoot_Storage.load();
+            assert(in.senderAddress == st.owner, MerkleRoot_Error.NotOwner);
+            onFreeze(st);
+        }
         else => {
             // ignore empty messages, "wrong opcode" for others
             assert (in.body.isEmpty()) throw 0xFFFF
@@ -107,6 +112,22 @@ fun onInitExecute(mutate st: MerkleRoot_Storage, msg: MerkleRoot_Validate) {
     executeValidated.send(SEND_MODE_CARRY_ALL_REMAINING_MESSAGE_VALUE);
 }
 
+fun onFreeze(st: MerkleRoot_Storage) {
+    var seqNum = st.minMsgNr;
+    while (seqNum <= st.maxMsgNr) {
+        val state = st.getMessageState(seqNum);
+        assert(state != ExecutionState.Untouched, MerkleRoot_Error.CannotFreezeWithUntouchedMessages);
+        seqNum += 1;
+    }
+    val drainMsg = createMessage({
+        bounce: false,
+        value: 0,
+        dest: st.owner,
+        body: createEmptyCell()
+    });
+    drainMsg.send(SEND_MODE_CARRY_ALL_BALANCE);
+}
+
 get fun typeAndVersion(): (slice, slice) {
     return ("com.chainlink.ton.ccip.MerkleRoot", CONTRACT_VERSION);
 }

contracts/contracts/ccip/merkle_root/errors.tolk

@@ -5,4 +5,5 @@ enum MerkleRoot_Error {
     SkippedAlreadyExecutedMessage
     InvalidState
     SeqNumOutOfBounds
+    CannotFreezeWithUntouchedMessages
 }

contracts/contracts/ccip/merkle_root/messages.tolk

@@ -3,7 +3,8 @@ import "../offramp/messages"
 
 type MerkleRoot_InMessage = 
     | MerkleRoot_Validate
-    | MerkleRoot_MarkState;
+    | MerkleRoot_MarkState
+    | MerkleRoot_Freeze;
 
 struct (0x038ede91) MerkleRoot_Validate {
     message: Cell<Any2TVMRampMessage>,
@@ -12,12 +13,13 @@ struct (0x038ede91) MerkleRoot_Validate {
     gasOverride: coins?,
 }
 
-//crc32('MerkleRoot_MarkState')
 struct (0x019f4cd2) MerkleRoot_MarkState {
     seqNum: uint64,
     state: ExecutionState
 }
 
+struct (0x0214e358) MerkleRoot_Freeze {}
+
 struct MerkleRoot_Costs{}
 
 fun MerkleRoot_Costs.validate(): int {

contracts/contracts/ccip/offramp/contract.tolk

@@ -111,6 +111,18 @@ fun onInternalMessage(in:InMessage) {
             onSetDynamicConfig(msg);
         }
         // Sender must be owner
+        OffRamp_FreezeMerkleRoot => {
+            val st = lazy Storage.load();
+            st.ownable.requireOwner(in.senderAddress);
+            onFreezeMerkleRoot(msg);
+        }
+        // Sender must be owner
+        OffRamp_FreezeReceiveExecutor => {
+            val st = lazy Storage.load();
+            st.ownable.requireOwner(in.senderAddress);
+            onFreezeReceiveExecutor(msg);
+        }
+        // Sender must be owner
         Withdrawable_Withdraw => {
             var st = lazy Storage.load();
             st.ownable.requireOwner(in.senderAddress);
@@ -697,6 +709,27 @@ fun onExecuteValidated(st: Storage, msg: OffRamp_ExecuteValidated, sender: addre
     initExecMsg.send(SEND_MODE_PAY_FEES_SEPARATELY);
 }
 
+//Sends Freeze message to merkle root
+fun onFreezeMerkleRoot(msg: OffRamp_FreezeMerkleRoot) {
+    val freezeMessage = createMessage ({
+        bounce: true,
+        value: 0,
+        dest: msg.merkleRootAddress,
+        body: MerkleRoot_Freeze{},
+    });
+    freezeMessage.send(SEND_MODE_CARRY_ALL_REMAINING_MESSAGE_VALUE);
+}
+
+fun onFreezeReceiveExecutor(msg: OffRamp_FreezeReceiveExecutor) {
+    val freezeMessage = createMessage ({
+        bounce: true,
+        value: 0,
+        dest: msg.receiveExecutorAddress,
+        body: ReceiveExecutor_Freeze{},
+    });
+    freezeMessage.send(SEND_MODE_CARRY_ALL_REMAINING_MESSAGE_VALUE);
+}
+
 /*
 Retrieves the Router address associated with a given sourceChainSelector.
 Throws an error if the source chain is not enabled in the stored configs.

contracts/contracts/ccip/offramp/messages.tolk

@@ -20,15 +20,17 @@ type OffRamp_InMessage =
     | OffRamp_UpdateSourceChainConfigs
     | OffRamp_CCIPReceiveConfirm
     | OffRamp_CCIPReceiveBounced
-    | OffRamp_NotifyFailure
     | OffRamp_NotifySuccess
     | OffRamp_NotifyFailure
     | OffRamp_UpdateCursedSubjects
     | OffRamp_SetDynamicConfig
     | OCR3Base_SetOCR3Config
     | OffRamp_UpdateDeployables
+    | OffRamp_FreezeMerkleRoot
+    | OffRamp_FreezeReceiveExecutor
     | Upgradeable_Upgrade
-    | Withdrawable_Withdraw;
+    | Withdrawable_Withdraw
+    ;
 
 struct (0x9d431905) OffRamp_Commit {
     queryId: uint64;
@@ -113,6 +115,16 @@ struct (0xa015e0e2) OffRamp_UpdateDeployables {
     merkleRootCode: cell?;
 }
 
+struct (0x304e248f) OffRamp_FreezeMerkleRoot {
+    queryId: uint64;
+    merkleRootAddress: address;
+}
+
+struct (0x97f24208) OffRamp_FreezeReceiveExecutor{
+    queryId: uint64;
+    receiveExecutorAddress: address;
+}
+
 struct OffRamp_Costs{}
 
 fun OffRamp_Costs.executeValidated(): int {

contracts/contracts/ccip/receive_executor/contract.tolk

@@ -32,6 +32,11 @@ fun onInternalMessage(in: InMessage) {
             onCCIPReceiveBounced(mutate st, msg);
             st.store();
         }
+        ReceiveExecutor_Freeze => {
+            var st = ReceiveExecutor_Storage.load();
+            assert(in.senderAddress == st.owner, Error.Unauthorized);
+            onFreeze(st);
+        }
         else => {
             // ignore empty messages, "wrong opcode" for others
             assert (in.body.isEmpty()) throw 0xFFFF
@@ -107,6 +112,17 @@ fun onCCIPReceiveBounced(mutate st: ReceiveExecutor_Storage, msg: ReceiveExecuto
     notifyFailure.send(SEND_MODE_CARRY_ALL_REMAINING_MESSAGE_VALUE);
 }
 
+fun onFreeze(st: ReceiveExecutor_Storage) {
+    assert(st.state != ReceiveExecutor_MessageState.Untouched, Error.CannotFreezeWithUntouchedState);
+    val drainMsg = createMessage({
+        bounce: false,
+        value: 0,
+        dest: st.owner,
+        body: createEmptyCell()
+    });
+    drainMsg.send(SEND_MODE_CARRY_ALL_BALANCE);
+}
+
 get fun typeAndVersion(): (slice, slice) {
     return ("com.chainlink.ton.ccip.ReceiveExecutor", CONTRACT_VERSION);
 }

contracts/contracts/ccip/receive_executor/errors.tolk

@@ -3,4 +3,5 @@ enum Error {
     UpdatingStateOfNonExecutedMessage
     NotificationFromInvalidReceiver
     Unauthorized
+    CannotFreezeWithUntouchedState
 }

contracts/contracts/ccip/receive_executor/messages.tolk

@@ -3,7 +3,8 @@ import "../offramp/messages"
 type ReceiveExecutor_InMessage =
     | ReceiveExecutor_InitExecute
     | ReceiveExecutor_Bounced
-    | ReceiveExecutor_Confirm;
+    | ReceiveExecutor_Confirm
+    | ReceiveExecutor_Freeze;
 
 struct (0x64cd2fd2) ReceiveExecutor_InitExecute {
     gasOverride: coins? = null;
@@ -17,6 +18,8 @@ struct (0x05dee1bb) ReceiveExecutor_Bounced {
     receiver: address
 }
 
+struct (0x1571d8c6) ReceiveExecutor_Freeze {}
+
 const RECEIVE_EXECUTOR_COSTS_CONFIRMED_OR_BOUNCED_FEE = ton("0.007");
 const RECEIVE_EXECUTOR_COSTS_INIT_EXEC_FEE = ton("0.004");