feat: added jwt decoding (#13)

relay_rpc/Cargo.toml

@@ -16,3 +16,4 @@ rand = "0.7"
 chrono = { version = "0.4", default-features = false, features = ["std", "clock"] }
 regex = "1.7"
 once_cell = "1.16"
+jsonwebtoken = "8.1"

relay_rpc/src/auth.rs

@@ -1,5 +1,8 @@
+#[cfg(test)]
+mod tests;
+
 use {
-    crate::domain::{AuthSubject, DecodedClientId},
+    crate::domain::{AuthSubject, ClientId, ClientIdDecodingError, DecodedClientId},
     chrono::{DateTime, Utc},
     ed25519_dalek::{ed25519::signature::Signature, Keypair, Signer},
     serde::{Deserialize, Serialize},
@@ -114,12 +117,28 @@ pub struct JwtClaims<'a> {
 }
 
 impl<'a> JwtClaims<'a> {
-    pub fn is_valid(&self, aud: &HashSet<String>, time_leeway: impl Into<Option<i64>>) -> bool {
+    pub fn validate(
+        &self,
+        aud: &HashSet<String>,
+        time_leeway: impl Into<Option<i64>>,
+    ) -> Result<(), JwtVerificationError> {
         let time_leeway = time_leeway
             .into()
             .unwrap_or(JWT_VALIDATION_TIME_LEEWAY_SECS);
         let now = Utc::now().timestamp();
-        (now + time_leeway) >= self.iat && (now - time_leeway) <= self.exp && aud.contains(self.aud)
+
+        if now - time_leeway > self.exp {
+            return Err(JwtVerificationError::Expired);
+        }
+
+        if now + time_leeway < self.iat {
+            return Err(JwtVerificationError::NotYetValid);
+        }
+
+        if !aud.contains(self.aud) {
+            return Err(JwtVerificationError::InvalidAudience);
+        }
+        Ok(())
     }
 }
 
@@ -170,3 +189,125 @@ pub fn encode_auth_token(
 
     Ok(SerializedAuthToken(format!("{message}.{signature}")))
 }
+
+#[derive(Debug, thiserror::Error)]
+pub enum JwtVerificationError {
+    #[error("Invalid format")]
+    Format,
+
+    #[error("Invalid encoding")]
+    Encoding,
+
+    #[error("Invalid JWT signing algorithm")]
+    Header,
+
+    #[error("JWT Token is expired")]
+    Expired,
+
+    #[error("JWT Token is not yet valid")]
+    NotYetValid,
+
+    #[error("Invalid audience")]
+    InvalidAudience,
+
+    #[error("Invalid signature")]
+    Signature,
+
+    #[error("Invalid JSON")]
+    Serialization,
+
+    #[error("Invalid issuer DID prefix")]
+    IssuerPrefix,
+
+    #[error("Invalid issuer DID method")]
+    IssuerMethod,
+
+    #[error("Invalid issuer format")]
+    IssuerFormat,
+
+    #[error(transparent)]
+    PubKey(#[from] ClientIdDecodingError),
+}
+
+#[derive(Debug)]
+pub struct Jwt(pub String);
+
+impl Jwt {
+    pub fn decode(&self, aud: &HashSet<String>) -> Result<ClientId, JwtVerificationError> {
+        let mut parts = self.0.splitn(3, JWT_DELIMITER);
+
+        let (Some(header), Some(claims)) = (parts.next(), parts.next()) else {
+            return Err(JwtVerificationError::Format);
+        };
+
+        let decoder = &data_encoding::BASE64URL_NOPAD;
+
+        let header_len = decoder
+            .decode_len(header.len())
+            .map_err(|_| JwtVerificationError::Encoding)?;
+        let claims_len = decoder
+            .decode_len(claims.len())
+            .map_err(|_| JwtVerificationError::Encoding)?;
+
+        let mut output = vec![0u8; header_len.max(claims_len)];
+
+        // Decode header.
+        data_encoding::BASE64URL_NOPAD
+            .decode_mut(header.as_bytes(), &mut output[..header_len])
+            .map_err(|_| JwtVerificationError::Encoding)?;
+
+        {
+            let header = serde_json::from_slice::<JwtHeader>(&output[..header_len])
+                .map_err(|_| JwtVerificationError::Serialization)?;
+
+            if !header.is_valid() {
+                return Err(JwtVerificationError::Header);
+            }
+        }
+
+        // Decode claims.
+        data_encoding::BASE64URL_NOPAD
+            .decode_mut(claims.as_bytes(), &mut output[..claims_len])
+            .map_err(|_| JwtVerificationError::Encoding)?;
+
+        let claims = serde_json::from_slice::<JwtClaims>(&output[..claims_len])
+            .map_err(|_| JwtVerificationError::Serialization)?;
+
+        // Basic token validation: `iat`, `exp` and `aud`.
+        claims.validate(aud, None)?;
+
+        let did_key = claims
+            .iss
+            .strip_prefix(DID_PREFIX)
+            .ok_or(JwtVerificationError::IssuerPrefix)?
+            .strip_prefix(DID_DELIMITER)
+            .ok_or(JwtVerificationError::IssuerFormat)?
+            .strip_prefix(DID_METHOD)
+            .ok_or(JwtVerificationError::IssuerMethod)?
+            .strip_prefix(DID_DELIMITER)
+            .ok_or(JwtVerificationError::IssuerFormat)?;
+
+        let pub_key = did_key.parse::<DecodedClientId>()?;
+
+        let mut parts = self.0.rsplitn(2, JWT_DELIMITER);
+
+        let (Some(signature), Some(message)) = (parts.next(), parts.next()) else {
+            return Err(JwtVerificationError::Format);
+        };
+
+        let key = jsonwebtoken::DecodingKey::from_ed_der(pub_key.as_ref());
+
+        // Finally, verify signature.
+        let sig_result = jsonwebtoken::crypto::verify(
+            signature,
+            message.as_bytes(),
+            &key,
+            jsonwebtoken::Algorithm::EdDSA,
+        );
+
+        match sig_result {
+            Ok(true) => Ok(pub_key.into()),
+            _ => Err(JwtVerificationError::Signature),
+        }
+    }
+}

relay_rpc/src/auth/tests.rs

@@ -0,0 +1,131 @@
+use {
+    crate::{
+        auth::{AuthToken, Jwt, JwtVerificationError, JWT_VALIDATION_TIME_LEEWAY_SECS},
+        domain::{ClientIdDecodingError, DecodedAuthSubject},
+    },
+    ed25519_dalek::Keypair,
+    std::{collections::HashSet, time::Duration},
+};
+
+#[test]
+fn token_validation() {
+    let aud = HashSet::from(["wss://relay.walletconnect.com".to_owned()]);
+
+    // Invalid signature.
+    let jwt = Jwt("eyJhbGciOiJFZERTQSIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJkaWQ6a2V5Ono2TWtvZEhad25lVlJTaHRhTGY4SktZa3hwREdwMXZHWm5wR21kQnBYOE0yZXh4SCIsInN1YiI6ImM0NzlmZTVkYzQ2NGU3NzFlNzhiMTkzZDIzOWE2NWI1OGQyNzhjYWQxYzM0YmZiMGI1NzE2ZTViYjUxNDkyOGUiLCJhdWQiOiJ3c3M6Ly9yZWxheS53YWxsZXRjb25uZWN0LmNvbSIsImlhdCI6MTY1NjkxMDA5NywiZXhwIjo0ODEyNjcwMDk3fQ.CLryc7bGZ_mBVh-P5p2tDDkjY8m9ji9xZXixJCbLLd4TMBh7F0EkChbWOOUQp4DyXUVK4CN-hxMZgt2xnePUBAx".to_owned());
+    assert!(matches!(
+        jwt.decode(&aud),
+        Err(JwtVerificationError::Signature)
+    ));
+
+    // Invalid multicodec header.
+    let jwt = Jwt("eyJhbGciOiJFZERTQSIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJkaWQ6a2V5Ono2TWt2eDRWVnVCQlBIekVvTERiNWdOQzRyUW1uSnN0YzFib29oS2ZjSlV0OU12NjUiLCJzdWIiOiJjNDc5ZmU1ZGM0NjRlNzcxZTc4YjE5M2QyMzlhNjViNThkMjc4Y2FkMWMzNGJmYjBiNTcxNmU1YmI1MTQ5MjhlIiwiYXVkIjoid3NzOi8vcmVsYXkud2FsbGV0Y29ubmVjdC5jb20iLCJpYXQiOjE2NTY5MTAwOTcsImV4cCI6NDgxMjY3MDA5N30.ixjxEISufsDpdsp4MRwD4Q100d8s7v4mSlIWIad6q8Nh__768pzPaCAVXQIZLxKPhuJQ92cZi7tVUJtAE1_UCg".to_owned());
+    assert!(matches!(
+        jwt.decode(&aud),
+        Err(JwtVerificationError::PubKey(
+            ClientIdDecodingError::Encoding
+        ))
+    ));
+
+    // Invalid multicodec base.
+    let jwt = Jwt("eyJhbGciOiJFZERTQSIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJkaWQ6a2V5Onh6Nk1rb2RIWnduZVZSU2h0YUxmOEpLWWt4cERHcDF2R1pucEdtZEJwWDhNMmV4eEgiLCJzdWIiOiJjNDc5ZmU1ZGM0NjRlNzcxZTc4YjE5M2QyMzlhNjViNThkMjc4Y2FkMWMzNGJmYjBiNTcxNmU1YmI1MTQ5MjhlIiwiYXVkIjoid3NzOi8vcmVsYXkud2FsbGV0Y29ubmVjdC5jb20iLCJpYXQiOjE2NTY5MTAwOTcsImV4cCI6NDgxMjY3MDA5N30.BINvB6JpUyp5Zs7qbIYMv7KybptioYFZP89ZFTMtvdGvEnRpYg70uzwSLdhZB1EPJZIrUMhybfT7Q1DYEqHwDw".to_owned());
+    assert!(matches!(
+        jwt.decode(&aud),
+        Err(JwtVerificationError::PubKey(ClientIdDecodingError::Base))
+    ));
+
+    // Invalid DID prefix.
+    let jwt = Jwt("eyJhbGciOiJFZERTQSIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJ4ZGlkOmtleTp6Nk1rb2RIWnduZVZSU2h0YUxmOEpLWWt4cERHcDF2R1pucEdtZEJwWDhNMmV4eEgiLCJzdWIiOiJjNDc5ZmU1ZGM0NjRlNzcxZTc4YjE5M2QyMzlhNjViNThkMjc4Y2FkMWMzNGJmYjBiNTcxNmU1YmI1MTQ5MjhlIiwiYXVkIjoid3NzOi8vcmVsYXkud2FsbGV0Y29ubmVjdC5jb20iLCJpYXQiOjE2NTY5MTAwOTcsImV4cCI6NDgxMjY3MDA5N30.GGhlhz7kXCqCTUsn390O_hA9YQDa61d_DDiSVLsa70xrgFrGmjjoWWl1dsZn3RVq4V1IB0P1__NDJ2PK0OMiDA".to_owned());
+    assert!(matches!(
+        jwt.decode(&aud),
+        Err(JwtVerificationError::IssuerPrefix)
+    ));
+
+    // Invalid DID method
+    let jwt = Jwt("eyJhbGciOiJFZERTQSIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJkaWQ6eGtleTp6Nk1rb2RIWnduZVZSU2h0YUxmOEpLWWt4cERHcDF2R1pucEdtZEJwWDhNMmV4eEgiLCJzdWIiOiJjNDc5ZmU1ZGM0NjRlNzcxZTc4YjE5M2QyMzlhNjViNThkMjc4Y2FkMWMzNGJmYjBiNTcxNmU1YmI1MTQ5MjhlIiwiYXVkIjoid3NzOi8vcmVsYXkud2FsbGV0Y29ubmVjdC5jb20iLCJpYXQiOjE2NTY5MTAwOTcsImV4cCI6NDgxMjY3MDA5N30.rogEwjJLQFwbDm4psUty7MPkHrCrNiXxpwEYZ2nctppmF7MYvC3g7URZNYkKxMbFtNZ1hFCwsr1peEu3pVeJCg".to_owned());
+    assert!(matches!(
+        jwt.decode(&aud),
+        Err(JwtVerificationError::IssuerMethod)
+    ));
+
+    // Invalid issuer base58.
+    let jwt = Jwt("eyJhbGciOiJFZERTQSIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJkaWQ6a2V5Ono2TWtvZEhad25lVlJTaHRhTGY4SktZa3hwREdwMXZHWm5wR21kQnBYOE0yZXh4SGwiLCJzdWIiOiJjNDc5ZmU1ZGM0NjRlNzcxZTc4YjE5M2QyMzlhNjViNThkMjc4Y2FkMWMzNGJmYjBiNTcxNmU1YmI1MTQ5MjhlIiwiYXVkIjoid3NzOi8vcmVsYXkud2FsbGV0Y29ubmVjdC5jb20iLCJpYXQiOjE2NTY5MTAwOTcsImV4cCI6NDgxMjY3MDA5N30.nLdxz4f6yJ8HsWZJUvpSHjFjoat4PfJav-kyqdHj6JXcX5SyDvp3QNB9doyzRWb9jpbA36Av0qn4kqLl-pGuBg".to_owned());
+    assert!(matches!(
+        jwt.decode(&aud),
+        Err(JwtVerificationError::PubKey(
+            ClientIdDecodingError::Encoding
+        ))
+    ));
+
+    let keypair = Keypair::generate(&mut rand::thread_rng());
+
+    // IAT in future.
+    let jwt = AuthToken::new(DecodedAuthSubject::generate())
+        .iat(chrono::Utc::now() + chrono::Duration::hours(1))
+        .as_jwt(&keypair)
+        .unwrap();
+    assert!(matches!(
+        Jwt(jwt.into()).decode(&aud),
+        Err(JwtVerificationError::NotYetValid)
+    ));
+
+    // IAT leeway, valid.
+    let jwt = AuthToken::new(DecodedAuthSubject::generate())
+        .iat(chrono::Utc::now() + chrono::Duration::seconds(JWT_VALIDATION_TIME_LEEWAY_SECS))
+        .as_jwt(&keypair)
+        .unwrap();
+    assert!(matches!(Jwt(jwt.into()).decode(&aud), Ok(_)));
+
+    // IAT leeway, invalid.
+    let jwt = AuthToken::new(DecodedAuthSubject::generate())
+        .iat(chrono::Utc::now() + chrono::Duration::seconds(JWT_VALIDATION_TIME_LEEWAY_SECS + 1))
+        .as_jwt(&keypair)
+        .unwrap();
+    assert!(matches!(
+        Jwt(jwt.into()).decode(&aud),
+        Err(JwtVerificationError::NotYetValid)
+    ));
+
+    // Past expiration.
+    let jwt = AuthToken::new(DecodedAuthSubject::generate())
+        .iat(chrono::Utc::now() - chrono::Duration::hours(2))
+        .ttl(Duration::from_secs(3600))
+        .as_jwt(&keypair)
+        .unwrap();
+    assert!(matches!(
+        Jwt(jwt.into()).decode(&aud),
+        Err(JwtVerificationError::Expired)
+    ));
+
+    // Expiration leeway, valid.
+    let jwt = AuthToken::new(DecodedAuthSubject::generate())
+        .iat(chrono::Utc::now() - chrono::Duration::seconds(3600 + JWT_VALIDATION_TIME_LEEWAY_SECS))
+        .ttl(Duration::from_secs(3600))
+        .as_jwt(&keypair)
+        .unwrap();
+    assert!(matches!(Jwt(jwt.into()).decode(&aud), Ok(_)));
+
+    // Expiration leeway, invalid.
+    let jwt = AuthToken::new(DecodedAuthSubject::generate())
+        .iat(
+            chrono::Utc::now()
+                - chrono::Duration::seconds(3600 + JWT_VALIDATION_TIME_LEEWAY_SECS + 1),
+        )
+        .ttl(Duration::from_secs(3600))
+        .as_jwt(&keypair)
+        .unwrap();
+    assert!(matches!(
+        Jwt(jwt.into()).decode(&aud),
+        Err(JwtVerificationError::Expired)
+    ));
+
+    // Invalid aud.
+    let jwt = AuthToken::new(DecodedAuthSubject::generate())
+        .aud("wss://not.relay.walletconnect.com")
+        .as_jwt(&keypair)
+        .unwrap();
+    assert!(matches!(
+        Jwt(jwt.into()).decode(&aud),
+        Err(JwtVerificationError::InvalidAudience)
+    ));
+}