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Use a single txn for an entire coordinator message

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Removes direct DB accesses whre possible. Documents the safety of the rest.
Does uncover one case of unsafety not previously noted.
This commit is contained in:
Luke Parker
2023-04-17 23:20:48 -04:00
parent 7579c71765
commit fd1bbec134
12 changed files with 370 additions and 284 deletions
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66
processor/src/signer.rs
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@@ -57,8 +57,8 @@ impl<C: Coin, D: Db> SignerDb<C, D> {
existing.extend(tx.as_ref());
txn.put(Self::completed_key(id), existing);
}
fn completed(&self, id: [u8; 32]) -> Option<Vec<u8>> {
self.0.get(Self::completed_key(id))
fn completed<G: Get>(getter: &G, id: [u8; 32]) -> Option<Vec<u8>> {
getter.get(Self::completed_key(id))
}
fn eventuality_key(id: [u8; 32]) -> Vec<u8> {
@@ -67,9 +67,9 @@ impl<C: Coin, D: Db> SignerDb<C, D> {
fn save_eventuality(txn: &mut D::Transaction<'_>, id: [u8; 32], eventuality: C::Eventuality) {
txn.put(Self::eventuality_key(id), eventuality.serialize());
}
fn eventuality(&self, id: [u8; 32]) -> Option<C::Eventuality> {
fn eventuality<G: Get>(getter: &G, id: [u8; 32]) -> Option<C::Eventuality> {
Some(
C::Eventuality::read::<&[u8]>(&mut self.0.get(Self::eventuality_key(id))?.as_ref()).unwrap(),
C::Eventuality::read::<&[u8]>(&mut getter.get(Self::eventuality_key(id))?.as_ref()).unwrap(),
)
}
@@ -79,8 +79,8 @@ impl<C: Coin, D: Db> SignerDb<C, D> {
fn attempt(txn: &mut D::Transaction<'_>, id: &SignId) {
txn.put(Self::attempt_key(id), []);
}
fn has_attempt(&mut self, id: &SignId) -> bool {
self.0.get(Self::attempt_key(id)).is_some()
fn has_attempt<G: Get>(getter: &G, id: &SignId) -> bool {
getter.get(Self::attempt_key(id)).is_some()
}
fn save_transaction(txn: &mut D::Transaction<'_>, tx: &C::Transaction) {
@@ -89,8 +89,9 @@ impl<C: Coin, D: Db> SignerDb<C, D> {
}
pub struct Signer<C: Coin, D: Db> {
db: PhantomData<D>,
coin: C,
db: SignerDb<C, D>,
keys: ThresholdKeys<C::Curve>,
@@ -120,10 +121,11 @@ impl<C: Coin, D: Db> fmt::Debug for Signer<C, D> {
}
impl<C: Coin, D: Db> Signer<C, D> {
pub fn new(db: D, coin: C, keys: ThresholdKeys<C::Curve>) -> Signer<C, D> {
pub fn new(coin: C, keys: ThresholdKeys<C::Curve>) -> Signer<C, D> {
Signer {
db: PhantomData,
coin,
db: SignerDb(db, PhantomData),
keys,
@@ -136,7 +138,7 @@ impl<C: Coin, D: Db> Signer<C, D> {
}
}
pub async fn keys(&self) -> ThresholdKeys<C::Curve> {
pub fn keys(&self) -> ThresholdKeys<C::Curve> {
self.keys.clone()
}
@@ -172,10 +174,11 @@ impl<C: Coin, D: Db> Signer<C, D> {
pub async fn eventuality_completion(
&mut self,
txn: &mut D::Transaction<'_>,
id: [u8; 32],
tx_id: &<C::Transaction as Transaction<C>>::Id,
) {
if let Some(eventuality) = self.db.eventuality(id) {
if let Some(eventuality) = SignerDb::<C, D>::eventuality(txn, id) {
// Transaction hasn't hit our mempool/was dropped for a different signature
// The latter can happen given certain latency conditions/a single malicious signer
// In the case of a single malicious signer, they can drag multiple honest
@@ -193,10 +196,8 @@ impl<C: Coin, D: Db> Signer<C, D> {
debug!("eventuality for {} resolved in TX {}", hex::encode(id), hex::encode(tx_id));
// Stop trying to sign for this TX
let mut txn = self.db.0.txn();
SignerDb::<C, D>::save_transaction(&mut txn, &tx);
SignerDb::<C, D>::complete(&mut txn, id, tx_id);
txn.commit();
SignerDb::<C, D>::save_transaction(txn, &tx);
SignerDb::<C, D>::complete(txn, id, tx_id);
self.signable.remove(&id);
self.attempt.remove(&id);
@@ -221,8 +222,8 @@ impl<C: Coin, D: Db> Signer<C, D> {
}
}
async fn check_completion(&mut self, id: [u8; 32]) -> bool {
if let Some(txs) = self.db.completed(id) {
async fn check_completion(&mut self, txn: &mut D::Transaction<'_>, id: [u8; 32]) -> bool {
if let Some(txs) = SignerDb::<C, D>::completed(txn, id) {
debug!(
"SignTransaction/Reattempt order for {}, which we've already completed signing",
hex::encode(id)
@@ -255,8 +256,8 @@ impl<C: Coin, D: Db> Signer<C, D> {
}
}
async fn attempt(&mut self, id: [u8; 32], attempt: u32) {
if self.check_completion(id).await {
async fn attempt(&mut self, txn: &mut D::Transaction<'_>, id: [u8; 32], attempt: u32) {
if self.check_completion(txn, id).await {
return;
}
@@ -304,7 +305,7 @@ impl<C: Coin, D: Db> Signer<C, D> {
// branch again for something we've already attempted
//
// Only run if this hasn't already been attempted
if self.db.has_attempt(&id) {
if SignerDb::<C, D>::has_attempt(txn, &id) {
warn!(
"already attempted {} #{}. this is an error if we didn't reboot",
hex::encode(id.id),
@@ -313,9 +314,7 @@ impl<C: Coin, D: Db> Signer<C, D> {
return;
}
let mut txn = self.db.0.txn();
SignerDb::<C, D>::attempt(&mut txn, &id);
txn.commit();
SignerDb::<C, D>::attempt(txn, &id);
// Attempt to create the TX
let machine = match self.coin.attempt_send(tx).await {
@@ -338,23 +337,22 @@ impl<C: Coin, D: Db> Signer<C, D> {
pub async fn sign_transaction(
&mut self,
txn: &mut D::Transaction<'_>,
id: [u8; 32],
tx: C::SignableTransaction,
eventuality: C::Eventuality,
) {
if self.check_completion(id).await {
if self.check_completion(txn, id).await {
return;
}
let mut txn = self.db.0.txn();
SignerDb::<C, D>::save_eventuality(&mut txn, id, eventuality);
txn.commit();
SignerDb::<C, D>::save_eventuality(txn, id, eventuality);
self.signable.insert(id, tx);
self.attempt(id, 0).await;
self.attempt(txn, id, 0).await;
}
pub async fn handle(&mut self, msg: CoordinatorMessage) {
pub async fn handle(&mut self, txn: &mut D::Transaction<'_>, msg: CoordinatorMessage) {
match msg {
CoordinatorMessage::Preprocesses { id, mut preprocesses } => {
if self.verify_id(&id).is_err() {
@@ -440,11 +438,9 @@ impl<C: Coin, D: Db> Signer<C, D> {
};
// Save the transaction in case it's needed for recovery
let mut txn = self.db.0.txn();
SignerDb::<C, D>::save_transaction(&mut txn, &tx);
SignerDb::<C, D>::save_transaction(txn, &tx);
let tx_id = tx.id();
SignerDb::<C, D>::complete(&mut txn, id.id, &tx_id);
txn.commit();
SignerDb::<C, D>::complete(txn, id.id, &tx_id);
// Publish it
if let Err(e) = self.coin.publish_transaction(&tx).await {
@@ -463,7 +459,7 @@ impl<C: Coin, D: Db> Signer<C, D> {
}
CoordinatorMessage::Reattempt { id } => {
self.attempt(id.id, id.attempt).await;
self.attempt(txn, id.id, id.attempt).await;
}
CoordinatorMessage::Completed { key: _, id, tx: mut tx_vec } => {
@@ -479,7 +475,7 @@ impl<C: Coin, D: Db> Signer<C, D> {
}
tx.as_mut().copy_from_slice(&tx_vec);
self.eventuality_completion(id, &tx).await;
self.eventuality_completion(txn, id, &tx).await;
}
}
}