feat(sidecar): Signature checks (user, proposer) + refactor

bolt-sidecar/Cargo.toml

@@ -7,10 +7,12 @@ edition = "2021"
 # core
 clap = { version = "4.5.4", features = ["derive"] }
 tokio = { version = "1", features = ["full"] }
-secp256k1 = { version = "0.29.0", features = ["hashes", "rand"] }
 warp = "0.3.7"
 futures = "0.3"
 
+# crypto
+secp256k1 = { version = "0.29.0", features = ["hashes", "rand"] }
+
 # alloy
 alloy-rpc-client = { git = "https://github.com/alloy-rs/alloy", features = [
     "reqwest",
@@ -28,7 +30,7 @@ alloy-transport-http = { git = "https://github.com/alloy-rs/alloy" }
 alloy-transport-ws = { git = "https://github.com/alloy-rs/alloy" }
 alloy-pubsub = { git = "https://github.com/alloy-rs/alloy" }
 alloy-rpc-types = { git = "https://github.com/alloy-rs/alloy" }
-alloy-consensus = { git = "https://github.com/alloy-rs/alloy" }
+alloy-consensus = { git = "https://github.com/alloy-rs/alloy", features = ["k256"] }
 alloy-json-rpc = { git = "https://github.com/alloy-rs/alloy" }
 alloy-primitives = "0.7.1"
 alloy-rlp = "0.3"

bolt-sidecar/README.md

@@ -1,8 +1,11 @@
 # `bolt-sidecar`
+
 The Bolt sidecar is the main entrypoint for proposers to issue proposer commitments. Proposers should point their `builder-api` to the Bolt sidecar API in order to enable it.
 
 ## Functionality
+
 The sidecar is responsible for:
+
 1. Registering the preferences of the proposer
 2. Accepting (or rejecting) commitment requests
 3. Implementing pricing strategies
@@ -12,23 +15,27 @@ The sidecar is responsible for:
 7. Dealing with PBS failures by falling back to the local template
 
 ### Local Block Template
+
 The local block template serves 3 purposes:
+
 1. Building a fallback block in case the PBS pipeline fails
 2. Maintaining intermediate state to simulate commitment requests on
 3. Syncing with Ethereum state and invalidating stale commitments
 
-*What do we simulate?*
+_What do we simulate?_
 We only simulate in order to verify the validity of the transaction according to protocol rules. This means:
+
 1. The transaction sender should be able to pay for it: `balance >= value + fee`
 2. The transaction nonce should be higher than any previously known nonce
 3. The base fee should be able to cover the maximum base fee the target block can have: `max_base_fee = current_base_fee * 1.125^block_diff`
 
-*Building strategy*
+_Building strategy_
 The block template is built and simulated on in FIFO order.
 
-*Updating state*
+_Updating state_
 We store a list of commitment addresses along with their account state. For each new block, we should update that state and check if we have to invalidate any commitments. This is critical as we don't want to return an invalid block
 in case a fallback block is required.
 
 ## Running
-- We require Anvil to be installed in the $PATH for running tests
+
+- We require Anvil to be installed in the $PATH for running tests

bolt-sidecar/src/client.rs

@@ -7,7 +7,7 @@ use alloy::ClientBuilder;
 use alloy_eips::BlockNumberOrTag;
 use alloy_primitives::{Address, U256, U64};
 use alloy_rpc_client as alloy;
-use alloy_rpc_types::{AccountInfo, FeeHistory};
+use alloy_rpc_types::FeeHistory;
 use alloy_transport::TransportResult;
 use alloy_transport_http::Http;
 use reqwest::{Client, Url};

bolt-sidecar/src/config.rs

@@ -1,6 +1,7 @@
 use std::str::FromStr;
 
 use clap::Parser;
+use secp256k1::{rand, SecretKey};
 
 #[derive(Parser)]
 pub(super) struct Opts {
@@ -17,50 +18,48 @@ pub(super) struct Opts {
 
 pub struct Config {
     pub rpc_port: u16,
-    pub private_key: secp256k1::SecretKey,
+    pub private_key: SecretKey,
     pub limits: Limits,
 }
 
 impl Default for Config {
     fn default() -> Self {
         Self {
             rpc_port: 8000,
-            private_key: secp256k1::SecretKey::new(&mut secp256k1::rand::thread_rng()),
+            private_key: SecretKey::new(&mut rand::thread_rng()),
             limits: Limits::default(),
         }
     }
 }
 
-impl From<Opts> for Config {
-    fn from(opts: Opts) -> Self {
-        // Start with default config
+impl TryFrom<Opts> for Config {
+    type Error = eyre::Report;
+
+    fn try_from(opts: Opts) -> eyre::Result<Self> {
         let mut config = Config::default();
 
         if let Some(port) = opts.port {
             config.rpc_port = port;
         }
 
-        let private_key = secp256k1::SecretKey::from_str(&opts.private_key)
-            .expect("Invalid secpk256k1 private key");
-
-        config.private_key = private_key;
-
         if let Some(max_commitments) = opts.max_commitments {
-            config.limits.max_commitments_per_block = max_commitments;
+            config.limits.max_commitments_per_slot = max_commitments;
         }
 
-        config
+        config.private_key = SecretKey::from_str(&opts.private_key)?;
+
+        Ok(config)
     }
 }
 
 pub struct Limits {
-    pub max_commitments_per_block: usize,
+    pub max_commitments_per_slot: usize,
 }
 
 impl Default for Limits {
     fn default() -> Self {
         Self {
-            max_commitments_per_block: 6,
+            max_commitments_per_slot: 6,
         }
     }
 }

bolt-sidecar/src/crypto.rs

@@ -0,0 +1,53 @@
+use secp256k1::{ecdsa::Signature, Message, PublicKey, SecretKey};
+
+/// Trait for any types that can be signed and verified with ECDSA.
+/// This trait is used to abstract over the signing and verification of different types.
+pub trait SignableECDSA {
+    /// Create a digest of the object that can be signed.
+    /// This API doesn't enforce a specific hash or encoding method.
+    fn digest(&self) -> Message;
+
+    /// Sign the object with the given key. Returns the signature.
+    ///
+    /// Note: The default implementation should be used where possible.
+    fn sign(&self, key: &SecretKey) -> Signature {
+        secp256k1::Secp256k1::new().sign_ecdsa(&self.digest(), key)
+    }
+
+    /// Verify the signature of the object with the given public key.
+    ///
+    /// Note: The default implementation should be used where possible.
+    fn verify(&self, signature: &Signature, pubkey: &PublicKey) -> bool {
+        secp256k1::Secp256k1::new()
+            .verify_ecdsa(&self.digest(), signature, pubkey)
+            .is_ok()
+    }
+}
+
+/// A signer that can sign any type that implements `Signable{curve}` trait.
+pub struct Signer {
+    secp256k1_key: SecretKey,
+}
+
+impl Signer {
+    /// Create a new signer with the given SECP256K1 secret key.
+    pub fn new(secp256k1_key: SecretKey) -> Self {
+        Self { secp256k1_key }
+    }
+
+    /// Sign the given object with the SECP256K1 key and ECDSA algorithm.
+    pub fn sign_ecdsa<T: SignableECDSA>(&self, obj: &T) -> Signature {
+        obj.sign(&self.secp256k1_key)
+    }
+
+    /// Verify the given object with the SECP256K1 key and ECDSA algorithm.
+    #[allow(dead_code)]
+    pub fn verify_ecdsa<T: SignableECDSA>(
+        &self,
+        obj: &T,
+        sig: &Signature,
+        pubkey: &PublicKey,
+    ) -> bool {
+        obj.verify(sig, pubkey)
+    }
+}