feat: make cacao verification a feature (#18)

Author: heilhead

.github/workflows/ci.yaml

@@ -36,11 +36,11 @@ jobs:
             rust: nightly
           - name: "Tests"
             cmd: nextest
-            args: run --workspace --retries 3
+            args: run --workspace --all-features --features cacao --retries 3
             rust: stable
           - name: "Documentation Tests"
             cmd: test
-            args: --workspace --doc
+            args: --workspace --doc --all-features
             rust: stable
     env:
       RUST_BACKTRACE: full

relay_rpc/Cargo.toml

@@ -3,6 +3,9 @@ name = "relay_rpc"
 version = "0.1.0"
 edition = "2021"
 
+[features]
+cacao = ["dep:k256", "dep:sha3"]
+
 [dependencies]
 bs58 = "0.4"
 data-encoding = "2.3"
@@ -17,6 +20,5 @@ chrono = { version = "0.4", default-features = false, features = ["std", "clock"
 regex = "1.7"
 once_cell = "1.16"
 jsonwebtoken = "8.1"
-k256 = "0.13.0"
-sha3 = "0.10.6"
-hex = "0.4.3"
+k256 = { version = "0.13", optional = true }
+sha3 = { version = "0.10", optional = true }

relay_rpc/src/auth.rs

@@ -1,6 +1,7 @@
 #[cfg(test)]
 mod tests;
 
+#[cfg(feature = "cacao")]
 pub mod cacao;
 pub mod did;
 

relay_rpc/src/auth/cacao/mod.rs renamed to relay_rpc/src/auth/cacao.rs

@@ -2,16 +2,15 @@ use {
     self::{header::Header, payload::Payload, signature::Signature},
     core::fmt::Debug,
     serde::{Deserialize, Serialize},
-    std::fmt::{Display, Write as _},
-    thiserror::Error as ThisError,
+    std::fmt::{Display, Write},
 };
 
 pub mod header;
 pub mod payload;
 pub mod signature;
 
-/// Errors that can occur during JWT verification
-#[derive(Debug, ThisError)]
+/// Errors that can occur during Cacao verification.
+#[derive(Debug, thiserror::Error)]
 pub enum CacaoError {
     #[error("Invalid header")]
     Header,
@@ -29,6 +28,12 @@ pub enum CacaoError {
     Verification,
 }
 
+impl From<std::fmt::Error> for CacaoError {
+    fn from(_: std::fmt::Error) -> Self {
+        CacaoError::PayloadResources
+    }
+}
+
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
 pub enum Version {
     V1 = 1,
@@ -73,8 +78,8 @@ impl Cacao {
     const ETHEREUM: &'static str = "Ethereum";
 
     pub fn verify(&self) -> Result<bool, CacaoError> {
-        self.p.is_valid()?;
-        self.h.is_valid()?;
+        self.p.validate()?;
+        self.h.validate()?;
         self.s.verify(self)
     }
 
@@ -91,37 +96,38 @@ impl Cacao {
         );
 
         if let Some(statement) = &self.p.statement {
-            let _ = write!(message, "\n{}\n", statement);
+            write!(message, "\n{}\n", statement)?;
         }
 
-        let _ = write!(
+        write!(
             message,
             "\nURI: {}\nVersion: {}\nChain ID: {}\nNonce: {}\nIssued At: {}",
             self.p.aud,
             self.p.version,
             self.p.chain_id()?,
             self.p.nonce,
             self.p.iat
-        );
+        )?;
 
         if let Some(exp) = &self.p.exp {
-            let _ = write!(message, "\nExpiration Time: {}", exp);
+            write!(message, "\nExpiration Time: {}", exp)?;
         }
 
         if let Some(nbf) = &self.p.nbf {
-            let _ = write!(message, "\nNot Before: {}", nbf);
+            write!(message, "\nNot Before: {}", nbf)?;
         }
 
         if let Some(request_id) = &self.p.request_id {
-            let _ = write!(message, "\nRequest ID: {}", request_id);
+            write!(message, "\nRequest ID: {}", request_id)?;
         }
 
         if let Some(resources) = &self.p.resources {
             if !resources.is_empty() {
-                let _ = write!(message, "\nResources:");
-                resources.iter().for_each(|resource| {
-                    let _ = write!(message, "\n- {}", resource);
-                });
+                write!(message, "\nResources:")?;
+
+                for resource in resources {
+                    write!(message, "\n- {}", resource)?;
+                }
             }
         }
 

relay_rpc/src/auth/cacao/header.rs

@@ -9,7 +9,7 @@ pub struct Header {
 }
 
 impl Header {
-    pub fn is_valid(&self) -> Result<(), CacaoError> {
+    pub fn validate(&self) -> Result<(), CacaoError> {
         match self.t.as_str() {
             "eip4361" => Ok(()),
             _ => Err(CacaoError::Header),

relay_rpc/src/auth/cacao/payload.rs

@@ -26,8 +26,8 @@ impl Payload {
     const ISS_POSITION_OF_REFERENCE: usize = 3;
 
     /// TODO: write valdation
-    pub fn is_valid(&self) -> Result<bool, CacaoError> {
-        Ok(true)
+    pub fn validate(&self) -> Result<(), CacaoError> {
+        Ok(())
     }
 
     pub fn address(&self) -> Result<String, CacaoError> {

relay_rpc/src/auth/cacao/signature.rs

@@ -37,15 +37,16 @@ impl Eip191 {
             sha3::{Digest, Keccak256},
         };
 
-        let signature_bytes = hex::decode(guarantee_no_hex_prefix(signature))
+        let signature_bytes = data_encoding::HEXLOWER_PERMISSIVE
+            .decode(strip_hex_prefix(signature).as_bytes())
             .map_err(|_| CacaoError::Verification)?;
 
         let sig = Sig::try_from(&signature_bytes[..64]).map_err(|_| CacaoError::Verification)?;
         let recovery_id = RecoveryId::try_from(&signature_bytes[64] % 27)
             .map_err(|_| CacaoError::Verification)?;
 
         let recovered_key = VerifyingKey::recover_from_digest(
-            Keccak256::new_with_prefix(&self.eip191_bytes(message)),
+            Keccak256::new_with_prefix(self.eip191_bytes(message)),
             &sig,
             recovery_id,
         )
@@ -55,21 +56,17 @@ impl Eip191 {
             .chain_update(&recovered_key.to_encoded_point(false).as_bytes()[1..])
             .finalize()[12..];
 
-        let address_encoded = hex::encode(add);
+        let address_encoded = data_encoding::HEXLOWER_PERMISSIVE.encode(add);
 
-        if address_encoded.to_lowercase() != guarantee_no_hex_prefix(address).to_lowercase() {
+        if address_encoded.to_lowercase() != strip_hex_prefix(address).to_lowercase() {
             Err(CacaoError::Verification)
         } else {
             Ok(true)
         }
     }
 }
 
-/// Remove the 0x prefix from a hex string
-fn guarantee_no_hex_prefix(s: &str) -> &str {
-    if let Some(stripped) = s.strip_prefix("0x") {
-        stripped
-    } else {
-        s
-    }
+/// Remove the "0x" prefix from a hex string.
+fn strip_hex_prefix(s: &str) -> &str {
+    s.strip_prefix("0x").unwrap_or(s)
 }

relay_rpc/src/auth/cacao/tests.rs

@@ -2,7 +2,7 @@ use crate::auth::cacao::Cacao;
 
 /// Test that we can verify a Cacao
 #[test]
-fn cacao_verify_success() {
+fn verify_success() {
     let cacao_serialized = r#"{
       "h": {
         "t": "eip4361"
@@ -34,7 +34,7 @@ fn cacao_verify_success() {
 
 /// Test that we can verify a Cacao with uppercase address
 #[test]
-fn cacao_without_lowercase_address_verify_success() {
+fn without_lowercase_address_verify_success() {
     let cacao_serialized = r#"{"h":{"t":"eip4361"},"p":{"iss":"did:pkh:eip155:1:0xbD4D1935165012e7D29919dB8717A5e670a1a5b1","domain":"https://staging.keys.walletconnect.com","aud":"https://staging.keys.walletconnect.com","version":"1","nonce":"07487c09be5535dcbc341d8e35e5c9b4d3539a802089c42c5b1172dd9ed63c64","iat":"2023-01-25T15:08:36.846Z","statement":"Test","resources":["did:key:451cf9b97c64fcca05fbb0d4c40b886c94133653df5a2b6bd97bd29a0bbcdb37"]},"s":{"t":"eip191","s":"0x8496ad1dd1ddd5cb78ac26b62a6bd1c6cfff703ea3b11a9da29cfca112357ace75cac8ee28d114f9e166a6935ee9ed83151819a9e0ee738a0547116b1d978e351b"}}"#;
     let cacao: Cacao = serde_json::from_str(cacao_serialized).unwrap();
     let result = cacao.verify();

relay_rpc/src/auth/did.rs

@@ -3,9 +3,7 @@ pub const DID_PREFIX: &str = "did";
 pub const DID_METHOD_KEY: &str = "key";
 pub const DID_METHOD_PKH: &str = "pkh";
 
-use thiserror::Error as ThisError;
-
-#[derive(Debug, ThisError)]
+#[derive(Debug, thiserror::Error)]
 pub enum DidError {
     #[error("Invalid issuer DID prefix")]
     Prefix,
@@ -17,15 +15,13 @@ pub enum DidError {
     Format,
 }
 
-pub fn extract_did_data<'a>(did: &'a str, method: &'a str) -> Result<&'a str, DidError> {
-    let data = did
-        .strip_prefix(DID_PREFIX)
+pub fn extract_did_data<'a>(did: &'a str, method: &str) -> Result<&'a str, DidError> {
+    did.strip_prefix(DID_PREFIX)
         .ok_or(DidError::Prefix)?
         .strip_prefix(DID_DELIMITER)
         .ok_or(DidError::Format)?
         .strip_prefix(method)
         .ok_or(DidError::Method)?
         .strip_prefix(DID_DELIMITER)
-        .ok_or(DidError::Format)?;
-    Ok(data)
+        .ok_or(DidError::Format)
 }