Randomize secp contexts for marginally better sidechannel resistance

[rust-lightning] / lightning / src / chain / channelmonitor.rs

diff --git a/lightning/src/chain/channelmonitor.rs b/lightning/src/chain/channelmonitor.rs
index 71490dd6e0e1af4de7b19b71e8699da47d5c2f46..a830c8216a6a4e8fe0e631763380ea12b05836ee 100644 (file)
--- a/lightning/src/chain/channelmonitor.rs
+++ b/lightning/src/chain/channelmonitor.rs
@@ -951,7 +951,7 @@ impl<Signer: Sign> Writeable for ChannelMonitor<Signer> {
 }
 
 impl<Signer: Sign> ChannelMonitor<Signer> {
-       pub(crate) fn new(keys: Signer, shutdown_pubkey: &PublicKey,
+       pub(crate) fn new(secp_ctx: Secp256k1<secp256k1::All>, keys: Signer, shutdown_pubkey: &PublicKey,
                          on_counterparty_tx_csv: u16, destination_script: &Script, funding_info: (OutPoint, Script),
                          channel_parameters: &ChannelTransactionParameters,
                          funding_redeemscript: Script, channel_value_satoshis: u64,
@@ -972,8 +972,6 @@ impl<Signer: Sign> ChannelMonitor<Signer> {
                let channel_keys_id = keys.channel_keys_id();
                let holder_revocation_basepoint = keys.pubkeys().revocation_basepoint;
 
-               let secp_ctx = Secp256k1::new();
-
                // block for Rust 1.34 compat
                let (holder_commitment_tx, current_holder_commitment_number) = {
                        let trusted_tx = initial_holder_commitment_tx.trust();
@@ -994,7 +992,8 @@ impl<Signer: Sign> ChannelMonitor<Signer> {
                };
 
                let onchain_tx_handler =
-                       OnchainTxHandler::new(destination_script.clone(), keys, channel_parameters.clone(), initial_holder_commitment_tx);
+                       OnchainTxHandler::new(destination_script.clone(), keys,
+                       channel_parameters.clone(), initial_holder_commitment_tx, secp_ctx.clone());
 
                let mut outputs_to_watch = HashMap::new();
                outputs_to_watch.insert(funding_info.0.txid, vec![(funding_info.0.index as u32, funding_info.1.clone())]);
@@ -2558,6 +2557,9 @@ impl<'a, Signer: Sign, K: KeysInterface<Signer = Signer>> ReadableArgs<&'a K>
                let lockdown_from_offchain = Readable::read(reader)?;
                let holder_tx_signed = Readable::read(reader)?;
 
+               let mut secp_ctx = Secp256k1::new();
+               secp_ctx.seeded_randomize(&keys_manager.get_secure_random_bytes());
+
                Ok((last_block_hash.clone(), ChannelMonitor {
                        latest_update_id,
                        commitment_transaction_number_obscure_factor,
@@ -2603,7 +2605,7 @@ impl<'a, Signer: Sign, K: KeysInterface<Signer = Signer>> ReadableArgs<&'a K>
                        holder_tx_signed,
 
                        last_block_hash,
-                       secp_ctx: Secp256k1::new(),
+                       secp_ctx,
                }))
        }
 }
@@ -2718,7 +2720,7 @@ mod tests {
                };
                // Prune with one old state and a holder commitment tx holding a few overlaps with the
                // old state.
-               let mut monitor = ChannelMonitor::new(keys,
+               let mut monitor = ChannelMonitor::new(Secp256k1::new(), keys,
                                                      &PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap()), 0, &Script::new(),
                                                      (OutPoint { txid: Txid::from_slice(&[43; 32]).unwrap(), index: 0 }, Script::new()),
                                                      &channel_parameters,