feat: EIP-1271 support (#55)

justfile

@@ -72,6 +72,21 @@ fmt:
     echo '    ^^^^^^ To install `rustup component add rustfmt`, see https://github.com/rust-lang/rustfmt for details'
   fi
 
+fmt-imports:
+  #!/bin/bash
+  set -euo pipefail
+
+  if command -v cargo-fmt >/dev/null; then
+    echo '==> Running rustfmt'
+    cargo +nightly fmt -- --config group_imports=StdExternalCrate,imports_granularity=One
+  else
+    echo '==> rustfmt not found in PATH, skipping'
+  fi
+
+unit: lint test test-all
+
+devloop: unit fmt-imports
+
 # Run commit checker
 commit-check:
   #!/bin/bash

relay_rpc/Cargo.toml

@@ -22,4 +22,17 @@ once_cell = "1.16"
 jsonwebtoken = "8.1"
 k256 = { version = "0.13", optional = true }
 sha3 = { version = "0.10", optional = true }
-sha2 = { version = "0.10.6" }
+sha2 = { version = "0.10.6" }
+reqwest = { version = "0.11", features = ["default-tls"] }
+url = "2"
+alloy-providers = { git = "https://github.com/alloy-rs/alloy.git", rev = "e6f98e1" }
+alloy-transport = { git = "https://github.com/alloy-rs/alloy.git", rev = "e6f98e1" }
+alloy-transport-http = { git = "https://github.com/alloy-rs/alloy.git", rev = "e6f98e1" }
+alloy-rpc-types = { git = "https://github.com/alloy-rs/alloy.git", rev = "e6f98e1" }
+alloy-json-rpc = { git = "https://github.com/alloy-rs/alloy.git", rev = "e6f98e1" }
+alloy-json-abi = "0.6.2"
+alloy-sol-types = "0.6.2"
+alloy-primitives = "0.6.2"
+
+[dev-dependencies]
+tokio = { version = "1.35.1", features = ["test-util", "macros"] }

relay_rpc/src/auth/cacao.rs

@@ -1,7 +1,12 @@
 use {
-    self::{header::Header, payload::Payload, signature::Signature},
+    self::{
+        header::Header,
+        payload::Payload,
+        signature::{eip1271::get_rpc_url::GetRpcUrl, Signature},
+    },
     core::fmt::Debug,
     serde::{Deserialize, Serialize},
+    serde_json::value::RawValue,
     std::fmt::{Display, Write},
 };
 
@@ -21,11 +26,20 @@ pub enum CacaoError {
     #[error("Invalid payload resources")]
     PayloadResources,
 
+    #[error("Invalid address")]
+    AddressInvalid,
+
     #[error("Unsupported signature type")]
     UnsupportedSignature,
 
+    #[error("Provider not available for that chain")]
+    ProviderNotAvailable,
+
     #[error("Unable to verify")]
     Verification,
+
+    #[error("Internal EIP-1271 resolution error: {0}")]
+    Eip1271Internal(alloy_json_rpc::RpcError<alloy_transport::TransportErrorKind, Box<RawValue>>),
 }
 
 impl From<std::fmt::Error> for CacaoError {
@@ -77,10 +91,10 @@ pub struct Cacao {
 impl Cacao {
     const ETHEREUM: &'static str = "Ethereum";
 
-    pub fn verify(&self) -> Result<bool, CacaoError> {
+    pub async fn verify(&self, provider: &impl GetRpcUrl) -> Result<bool, CacaoError> {
         self.p.validate()?;
         self.h.validate()?;
-        self.s.verify(self)
+        self.s.verify(self, provider).await
     }
 
     pub fn siwe_message(&self) -> Result<String, CacaoError> {

relay_rpc/src/auth/cacao/signature/eip1271/blockchain_api.rs

@@ -0,0 +1,59 @@
+use {super::get_rpc_url::GetRpcUrl, crate::domain::ProjectId, url::Url};
+
+// https://github.com/WalletConnect/blockchain-api/blob/master/SUPPORTED_CHAINS.md
+const SUPPORTED_CHAINS: [&str; 26] = [
+    "eip155:1",
+    "eip155:5",
+    "eip155:11155111",
+    "eip155:10",
+    "eip155:420",
+    "eip155:42161",
+    "eip155:421613",
+    "eip155:137",
+    "eip155:80001",
+    "eip155:1101",
+    "eip155:42220",
+    "eip155:1313161554",
+    "eip155:1313161555",
+    "eip155:56",
+    "eip155:56",
+    "eip155:43114",
+    "eip155:43113",
+    "eip155:324",
+    "eip155:280",
+    "near",
+    "eip155:100",
+    "solana:4sgjmw1sunhzsxgspuhpqldx6wiyjntz",
+    "eip155:8453",
+    "eip155:84531",
+    "eip155:7777777",
+    "eip155:999",
+];
+
+#[derive(Debug, Clone)]
+pub struct BlockchainApiProvider {
+    project_id: ProjectId,
+}
+
+impl BlockchainApiProvider {
+    pub fn new(project_id: ProjectId) -> Self {
+        Self { project_id }
+    }
+}
+
+impl GetRpcUrl for BlockchainApiProvider {
+    fn get_rpc_url(&self, chain_id: String) -> Option<Url> {
+        if SUPPORTED_CHAINS.contains(&chain_id.as_str()) {
+            Some(
+                format!(
+                    "https://rpc.walletconnect.com/v1?chainId={chain_id}&projectId={}",
+                    self.project_id
+                )
+                .parse()
+                .expect("Provider URL should be valid"),
+            )
+        } else {
+            None
+        }
+    }
+}

relay_rpc/src/auth/cacao/signature/eip1271/get_rpc_url.rs

@@ -0,0 +1,5 @@
+use url::Url;
+
+pub trait GetRpcUrl {
+    fn get_rpc_url(&self, chain_id: String) -> Option<Url>;
+}

relay_rpc/src/auth/cacao/signature/eip1271/mod.rs

@@ -0,0 +1,98 @@
+use {
+    super::CacaoError,
+    alloy_primitives::{Address, FixedBytes},
+    alloy_providers::provider::{Provider, TempProvider},
+    alloy_rpc_types::{CallInput, CallRequest},
+    alloy_sol_types::{sol, SolCall},
+    alloy_transport_http::Http,
+    url::Url,
+};
+
+pub mod blockchain_api;
+pub mod get_rpc_url;
+
+pub const EIP1271: &str = "eip1271";
+
+// https://eips.ethereum.org/EIPS/eip-1271
+const MAGIC_VALUE: u32 = 0x1626ba7e;
+sol! {
+    function isValidSignature(
+        bytes32 _hash,
+        bytes memory _signature)
+        public
+        view
+        returns (bytes4 magicValue);
+}
+
+pub async fn verify_eip1271(
+    signature: Vec<u8>,
+    address: Address,
+    hash: &[u8; 32],
+    provider: Url,
+) -> Result<bool, CacaoError> {
+    let provider = Provider::new(Http::new(provider));
+
+    let call_request = CallRequest {
+        to: Some(address),
+        input: CallInput::new(
+            isValidSignatureCall {
+                _hash: FixedBytes::from(hash),
+                _signature: signature,
+            }
+            .abi_encode()
+            .into(),
+        ),
+        ..Default::default()
+    };
+
+    let result = provider.call(call_request, None).await.map_err(|e| {
+        if let Some(error_response) = e.as_error_resp() {
+            if error_response.message.starts_with("execution reverted:") {
+                CacaoError::Verification
+            } else {
+                CacaoError::Eip1271Internal(e)
+            }
+        } else {
+            CacaoError::Eip1271Internal(e)
+        }
+    })?;
+
+    if result[..4] == MAGIC_VALUE.to_be_bytes().to_vec() {
+        Ok(true)
+    } else {
+        Err(CacaoError::Verification)
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use {
+        super::*,
+        crate::auth::cacao::signature::{eip191::eip191_bytes, strip_hex_prefix},
+        alloy_primitives::address,
+        sha3::{Digest, Keccak256},
+    };
+
+    // Manual test. Paste address, signature, message, and project ID to verify
+    // function
+    #[tokio::test]
+    #[ignore]
+    async fn test_eip1271() {
+        let address = address!("AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA");
+        let signature = "xxx";
+        let signature = data_encoding::HEXLOWER_PERMISSIVE
+            .decode(strip_hex_prefix(signature).as_bytes())
+            .map_err(|_| CacaoError::Verification)
+            .unwrap();
+        let message = "xxx";
+        let hash = &Keccak256::new_with_prefix(eip191_bytes(message)).finalize()[..]
+            .try_into()
+            .unwrap();
+        let provider = "https://rpc.walletconnect.com/v1?chainId=eip155:1&projectId=xxx"
+            .parse()
+            .unwrap();
+        assert!(verify_eip1271(signature, address, hash, provider)
+            .await
+            .unwrap());
+    }
+}

relay_rpc/src/auth/cacao/signature/eip191.rs

@@ -0,0 +1,39 @@
+use {
+    super::CacaoError,
+    crate::auth::cacao::signature::strip_hex_prefix,
+    sha3::{Digest, Keccak256},
+};
+
+pub const EIP191: &str = "eip191";
+
+pub fn eip191_bytes(message: &str) -> Vec<u8> {
+    format!(
+        "\u{0019}Ethereum Signed Message:\n{}{}",
+        message.as_bytes().len(),
+        message
+    )
+    .into()
+}
+
+pub fn verify_eip191(signature: &[u8], address: &str, hash: Keccak256) -> Result<bool, CacaoError> {
+    use k256::ecdsa::{RecoveryId, Signature as Sig, VerifyingKey};
+
+    let sig = Sig::try_from(&signature[..64]).map_err(|_| CacaoError::Verification)?;
+    let recovery_id =
+        RecoveryId::try_from(&signature[64] % 27).map_err(|_| CacaoError::Verification)?;
+
+    let recovered_key = VerifyingKey::recover_from_digest(hash, &sig, recovery_id)
+        .map_err(|_| CacaoError::Verification)?;
+
+    let add = &Keccak256::default()
+        .chain_update(&recovered_key.to_encoded_point(false).as_bytes()[1..])
+        .finalize()[12..];
+
+    let address_encoded = data_encoding::HEXLOWER_PERMISSIVE.encode(add);
+
+    if address_encoded.to_lowercase() != strip_hex_prefix(address).to_lowercase() {
+        Err(CacaoError::Verification)
+    } else {
+        Ok(true)
+    }
+}