fix[c-01]: reconstruct destination message from source and params (#75)

Signed-off-by: Reinis Martinsons <reinis@umaproject.org>

Author: Reinis-FRP

programs/sponsored-cctp-src-periphery/src/error.rs

@@ -37,3 +37,14 @@ pub enum SvmError {
     #[msg("Invalid recipient key")]
     InvalidRecipientKey,
 }
+
+// CCTP BurnMessageV2 specific errors.
+#[error_code]
+pub enum CctpBurnMessageV2Error {
+    #[msg("Malformed V2 burn message")]
+    MalformedMessage,
+    #[msg("Invalid message version")]
+    InvalidMessageVersion,
+    #[msg("Invalid message body version")]
+    InvalidMessageBodyVersion,
+}

programs/sponsored-cctp-src-periphery/src/instructions/deposit.rs

@@ -1,7 +1,6 @@
 use anchor_lang::{prelude::*, system_program};
 use anchor_spl::token_interface::{Mint, TokenAccount, TokenInterface};
 
-pub use crate::message_transmitter_v2::types::ReclaimEventAccountParams;
 use crate::{
     error::{CommonError, SvmError},
     event::{AccruedRentFundLiability, CreatedEventAccount, SponsoredDepositForBurn},

programs/sponsored-cctp-src-periphery/src/instructions/maintenance.rs

@@ -1,12 +1,12 @@
 use anchor_lang::{prelude::*, system_program};
 
-pub use crate::message_transmitter_v2::types::ReclaimEventAccountParams;
+pub use crate::message_transmitter_v2::types::ReclaimEventAccountParams as ReclaimEventAccountCctpV2Params;
 use crate::{
     error::SvmError,
     event::{ReclaimedEventAccount, ReclaimedUsedNonceAccount, RepaidRentFundDebt},
-    message_transmitter_v2::{self, program::MessageTransmitterV2},
+    message_transmitter_v2::{self, accounts::MessageSent, program::MessageTransmitterV2},
     state::{RentClaim, State, UsedNonce},
-    utils::get_current_time,
+    utils::{build_destination_message, get_current_time},
 };
 
 #[event_cpi]
@@ -79,14 +79,26 @@ pub struct ReclaimEventAccount<'info> {
     #[account(mut)]
     pub message_transmitter: UncheckedAccount<'info>,
 
-    /// CHECK: MessageSent is checked in CCTP, must be the same account as in DepositForBurn.
     #[account(mut)]
-    pub message_sent_event_data: UncheckedAccount<'info>,
+    pub message_sent_event_data: Account<'info, MessageSent>,
 
     pub message_transmitter_program: Program<'info, MessageTransmitterV2>,
 }
 
+#[derive(AnchorSerialize, AnchorDeserialize)]
+pub struct ReclaimEventAccountParams {
+    pub attestation: Vec<u8>,
+    pub nonce: [u8; 32],
+    pub finality_threshold_executed: [u8; 4],
+    pub fee_executed: [u8; 32],
+    pub expiration_block: [u8; 32],
+}
+
 pub fn reclaim_event_account(ctx: Context<ReclaimEventAccount>, params: &ReclaimEventAccountParams) -> Result<()> {
+    let destination_message = build_destination_message(&ctx.accounts.message_sent_event_data.message, params)?;
+    let cctp_v2_params =
+        ReclaimEventAccountCctpV2Params { attestation: params.attestation.clone(), destination_message };
+
     let cpi_program = ctx.accounts.message_transmitter_program.to_account_info();
     let cpi_accounts = message_transmitter_v2::cpi::accounts::ReclaimEventAccount {
         payee: ctx.accounts.rent_fund.to_account_info(),
@@ -95,7 +107,7 @@ pub fn reclaim_event_account(ctx: Context<ReclaimEventAccount>, params: &Reclaim
     };
     let rent_fund_seeds: &[&[&[u8]]] = &[&[b"rent_fund", &[ctx.bumps.rent_fund]]];
     let cpi_ctx = CpiContext::new_with_signer(cpi_program, cpi_accounts, rent_fund_seeds);
-    message_transmitter_v2::cpi::reclaim_event_account(cpi_ctx, params.clone())?;
+    message_transmitter_v2::cpi::reclaim_event_account(cpi_ctx, cctp_v2_params)?;
 
     emit_cpi!(ReclaimedEventAccount { message_sent_event_data: ctx.accounts.message_sent_event_data.key() });
 

programs/sponsored-cctp-src-periphery/src/lib.rs

@@ -198,11 +198,16 @@ pub mod sponsored_cctp_src_periphery {
     /// Required Accounts:
     /// - rent_fund (SystemAccount, Writable): PDA to receive reclaimed lamports. Seed: ["rent_fund"].
     /// - message_transmitter (Unchecked, Mutable): CCTP MessageTransmitter account.
-    /// - message_sent_event_data (Unchecked, Mutable): The event account created during `deposit_for_burn`.
+    /// - message_sent_event_data (Account, Mutable): The `MessageSent` event account created during `deposit_for_burn`.
     /// - message_transmitter_program (Program): CCTPv2 MessageTransmitter program.
     ///
     /// Parameters:
-    /// - params: Parameters required by CCTP to reclaim the event account.
+    /// - params: Parameters struct required to construct reclaim_event_account instruction on the CCTPv2.
+    ///   - attestation: Attestation obtained from the CCTP attestation service.
+    ///   - nonce: bytes32 from the attested destination message.
+    ///   - finality_threshold_executed: uint32 BE encoded from the attested destination message.
+    ///   - fee_executed: uint256 BE encoded from the attested destination message body.
+    ///   - expiration_block: uint256 BE encoded from the attested destination message body.
     ///
     /// Notes:
     /// - This can only be called after the CCTP attestation service has processed the message and sufficient time has

programs/sponsored-cctp-src-periphery/src/utils/cctp_v2_message.rs

@@ -0,0 +1,61 @@
+use anchor_lang::prelude::*;
+
+use crate::{error::CctpBurnMessageV2Error, instructions::ReclaimEventAccountParams};
+
+// Required CCTPv2 message constants from https://developers.circle.com/cctp/technical-guide#message-header
+const VERSION_INDEX: usize = 0;
+const VERSION_LEN: usize = 4; // uint32
+const SUPPORTED_VERSION: u32 = 1;
+const NONCE_INDEX: usize = 12;
+const NONCE_LEN: usize = 32; // bytes32
+const FINALITY_THRESHOLD_EXECUTED_INDEX: usize = 144;
+const FINALITY_THRESHOLD_EXECUTED_LEN: usize = 4; // uint32
+const MESSAGE_BODY_INDEX: usize = 148;
+
+// Required CCTPv2 message body constants from https://developers.circle.com/cctp/technical-guide#message-body
+const BODY_VERSION_INDEX: usize = MESSAGE_BODY_INDEX + 0;
+const BODY_VERSION_LEN: usize = 4; // uint32
+const SUPPORTED_BODY_VERSION: u32 = 1;
+const FEE_EXECUTED_INDEX: usize = MESSAGE_BODY_INDEX + 164;
+const FEE_EXECUTED_LEN: usize = 32; // uint256
+const EXPIRATION_BLOCK_INDEX: usize = MESSAGE_BODY_INDEX + 196;
+const EXPIRATION_BLOCK_LEN: usize = 32; // uint256
+const HOOK_DATA_INDEX: usize = MESSAGE_BODY_INDEX + 228;
+
+pub fn build_destination_message(source_message: &[u8], params: &ReclaimEventAccountParams) -> Result<Vec<u8>> {
+    if source_message.len() < HOOK_DATA_INDEX {
+        return err!(CctpBurnMessageV2Error::MalformedMessage);
+    }
+
+    let message_version = u32::from_be_bytes(
+        source_message[VERSION_INDEX..VERSION_INDEX + VERSION_LEN]
+            .try_into()
+            .unwrap(), // Safe as we check the length above.
+    );
+    if message_version != SUPPORTED_VERSION {
+        return err!(CctpBurnMessageV2Error::InvalidMessageVersion);
+    }
+
+    let message_body_version = u32::from_be_bytes(
+        source_message[BODY_VERSION_INDEX..BODY_VERSION_INDEX + BODY_VERSION_LEN]
+            .try_into()
+            .unwrap(), // Safe as we check the length above.
+    );
+    if message_body_version != SUPPORTED_BODY_VERSION {
+        return err!(CctpBurnMessageV2Error::InvalidMessageBodyVersion);
+    }
+
+    let mut destination_message = source_message.to_vec();
+
+    // Overwrite parameters that are changed in the destination message.
+    destination_message[NONCE_INDEX..NONCE_INDEX + NONCE_LEN].copy_from_slice(&params.nonce);
+    destination_message
+        [FINALITY_THRESHOLD_EXECUTED_INDEX..FINALITY_THRESHOLD_EXECUTED_INDEX + FINALITY_THRESHOLD_EXECUTED_LEN]
+        .copy_from_slice(&params.finality_threshold_executed);
+    destination_message[FEE_EXECUTED_INDEX..FEE_EXECUTED_INDEX + FEE_EXECUTED_LEN]
+        .copy_from_slice(&params.fee_executed);
+    destination_message[EXPIRATION_BLOCK_INDEX..EXPIRATION_BLOCK_INDEX + EXPIRATION_BLOCK_LEN]
+        .copy_from_slice(&params.expiration_block);
+
+    Ok(destination_message)
+}

programs/sponsored-cctp-src-periphery/src/utils/mod.rs

@@ -1,7 +1,9 @@
+pub mod cctp_v2_message;
 pub mod signer;
 pub mod sponsored_cctp_quote;
 pub mod testable_utils;
 
+pub use cctp_v2_message::*;
 pub use signer::*;
 pub use sponsored_cctp_quote::*;
 pub use testable_utils::*;