Support for certificates with expiration date

certifier/Cargo.toml

@@ -27,6 +27,12 @@ serde_json = "1.0.115"
 base64 = "0.22.0"
 axum-prometheus = "0.6.1"
 tower = { version = "0.4.13", features = ["limit"] }
+duration-str = { version = "0.7.1", default-features = false, features = [
+    "serde",
+    "time",
+] }
+parity-scale-codec = { version = "3.6.9", features = ["derive", "serde"] }
+mockall = "0.12.1"
 
 [dev-dependencies]
 reqwest = { version = "0.12.3", features = ["json"] }

certifier/README.md

@@ -28,6 +28,7 @@ The config structure is defined [here](src/configuration.rs). An example config:
 ```yaml
 listen: "127.0.0.1:8080"
 signing_key: <BASE64-encoded ed25519 private key>
+certificate_expiration: 2w
 post_cfg:
   k1: 26
   k2: 37
@@ -48,6 +49,10 @@ randomx_mode: Fast
 
 Each field can also be provided as env variable prefixed with CERTIFIER. For example, `CERTIFIER_SIGNING_KEY`.
 
+##### Expiring certificates
+The certificates don't expire by default. To create certificates that expire after certain time duration,
+set `certificate_expiration` field in the config. It understands units supported by the [duration_str](https://docs.rs/duration-str/0.7.1/duration_str/index.html) crate (i.e "1d", "2w").
+
 ##### Concurrency limit
 It's important to configure the maximum number of requests that will be processed in parallel.
 The POST verification is heavy on CPU and hence a value higher than the number of CPU cores might lead to drop in performance and increase latency.
@@ -74,4 +79,4 @@ Run `certifier generate-keys` to obtain randomly generated new keys.
 ```
 
 ## Log level
-The log level can be controlled via `RUST_LOG` enviroment variable. It can be set to [error, warn, info, debug, trace, off].
+The log level can be controlled via `RUST_LOG` enviroment variable. It can be set to [error, warn, info, debug, trace, off].

certifier/src/certifier.rs

@@ -1,17 +1,20 @@
 use std::sync::Arc;
+use std::time::{Duration, SystemTime};
 
 use axum::http::StatusCode;
 use axum::{extract::State, Json};
 use axum::{routing::post, Router};
-use ed25519_dalek::{Signer, SigningKey};
+use ed25519_dalek::{Signature, Signer, SigningKey};
+use parity_scale_codec::{Compact, Decode, Encode};
 use post::config::{InitConfig, ProofConfig};
 use post::pow::randomx::PoW;
-use post::verification::{Mode, Verifier};
+use post::verification::Mode;
 use serde::{Deserialize, Serialize};
 use serde_with::{base64::Base64, serde_as};
 use tracing::instrument;
 
 use crate::configuration::RandomXMode;
+use crate::time::unix_timestamp;
 
 #[derive(Debug, Deserialize, Serialize)]
 pub struct CertifyRequest {
@@ -20,71 +23,240 @@
 }
 
 #[serde_as]
-#[derive(Debug, Serialize)]
-struct CertifyResponse {
+#[derive(Debug, Serialize, Deserialize)]
+pub struct CertifyResponse {
+    /// The certificate as scale-encoded `Certificate` struct
     #[serde_as(as = "Base64")]
-    signature: Vec<u8>,
+    pub certificate: Vec<u8>,
+    /// Signature of the certificate
     #[serde_as(as = "Base64")]
-    pub_key: Vec<u8>,
+    pub signature: Vec<u8>,
+    /// The public key of the certifier that signed the certificate
+    #[serde_as(as = "Base64")]
+    pub pub_key: Vec<u8>,
+}
+
+#[derive(Debug, Decode, Encode)]
+pub struct Certificate {
+    // ID of the node being certified
+    pub pub_key: Vec<u8>,
+    /// Unix timestamp
+    pub expiration: Option<Compact<u64>>,
 }
 
 #[instrument(skip(state))]
 async fn certify(
-    State(state): State<Arc<AppState>>,
+    State(state): State<Arc<Certifier>>,
     Json(req): Json<CertifyRequest>,
 ) -> Result<Json<CertifyResponse>, (StatusCode, String)> {
     tracing::debug!("certifying");
 
-    let pub_key = req.metadata.node_id;
-    let my_id = state.signer.verifying_key().to_bytes();
     let s = state.clone();
+    let result = tokio::task::spawn_blocking(move || s.certify(&req.proof, &req.metadata))
+        .await
+        .map_err(|e| {
+            tracing::error!("internal error verifying proof: {e:?}");
+            (
+                StatusCode::INTERNAL_SERVER_ERROR,
+                "error verifying proof".into(),
+            )
+        })?;
 
-    let result = tokio::task::spawn_blocking(move || {
-        s.verifier
-            .verify(&req.proof, &req.metadata, &s.cfg, &s.init_cfg, Mode::All)
-    })
-    .await
-    .map_err(|e| {
-        tracing::error!("internal error verifying proof: {e:?}");
-        (
-            StatusCode::INTERNAL_SERVER_ERROR,
-            "error verifying proof".into(),
-        )
-    })?;
-
-    result.map_err(|e| (StatusCode::FORBIDDEN, format!("invalid proof: {e:?}")))?;
-
-    // Sign the nodeID
-    let response = CertifyResponse {
-        signature: state.signer.sign(&pub_key).to_vec(),
-        pub_key: my_id.to_vec(),
-    };
-    Ok(Json(response))
+    match result {
+        Ok(result) => {
+            let response = CertifyResponse {
+                certificate: result.0.to_vec(),
+                signature: result.1.to_vec(),
+                pub_key: state.signer.verifying_key().to_bytes().to_vec(),
+            };
+            Ok(Json(response))
+        }
+        Err(e) => {
+            return Err((StatusCode::FORBIDDEN, format!("invalid proof: {e:?}")));
+        }
+    }
 }
 
-struct AppState {
-    verifier: Verifier,
+#[mockall::automock]
+trait Verifier {
+    fn verify(
+        &self,
+        proof: &post::prove::Proof<'static>,
+        metadata: &post::metadata::ProofMetadata,
+    ) -> Result<(), String>;
+}
+
+struct PostVerifier {
+    verifier: post::verification::Verifier,
     cfg: ProofConfig,
     init_cfg: InitConfig,
+}
+
+impl Verifier for PostVerifier {
+    fn verify(
+        &self,
+        proof: &post::prove::Proof<'_>,
+        metadata: &post::metadata::ProofMetadata,
+    ) -> Result<(), String> {
+        self.verifier
+            .verify(proof, metadata, &self.cfg, &self.init_cfg, Mode::All)
+            .map_err(|e| format!("{e:?}"))
+    }
+}
+
+struct Certifier {
+    verifier: Arc<dyn Verifier + Send + Sync>,
     signer: SigningKey,
+    expiry: Option<Duration>,
+}
+
+impl Certifier {
+    pub fn certify(
+        &self,
+        proof: &post::prove::Proof<'static>,
+        metadata: &post::metadata::ProofMetadata,
+    ) -> Result<(Vec<u8>, Signature), String> {
+        self.verifier.verify(proof, metadata)?;
+
+        let cert = self.create_certificate(&metadata.node_id);
+        let cert_encoded = cert.encode();
+        let signature = self.signer.sign(&cert_encoded);
+
+        Ok((cert_encoded.to_vec(), signature))
+    }
+
+    fn create_certificate(&self, id: &[u8; 32]) -> Certificate {
+        let expiration = self
+            .expiry
+            .map(|exp| unix_timestamp(SystemTime::now() + exp));
+        Certificate {
+            pub_key: id.to_vec(),
+            expiration: expiration.map(Compact),
+        }
+    }
 }
 
 pub fn new(
     cfg: ProofConfig,
     init_cfg: InitConfig,
     signer: SigningKey,
     randomx_mode: RandomXMode,
+    expiry: Option<Duration>,
 ) -> Router {
-    let state = AppState {
-        verifier: Verifier::new(Box::new(
+    let verifier = Arc::new(PostVerifier {
+        verifier: post::verification::Verifier::new(Box::new(
             PoW::new(randomx_mode.into()).expect("creating RandomX PoW verifier"),
         )),
         cfg,
         init_cfg,
+    });
+    let certifier = Certifier {
+        verifier,
         signer,
+        expiry,
     };
 
     Router::new()
         .route("/certify", post(certify))
-        .with_state(Arc::new(state))
+        .with_state(Arc::new(certifier))
+}
+
+#[cfg(test)]
+mod tests {
+    use std::{
+        sync::Arc,
+        time::{Duration, SystemTime},
+    };
+
+    use crate::time::unix_timestamp;
+
+    use super::{Certificate, Certifier, MockVerifier};
+    use ed25519_dalek::SigningKey;
+    use parity_scale_codec::Decode;
+    use post::{metadata::ProofMetadata, prove::Proof};
+
+    #[test]
+    fn certify_invalid_post() {
+        let mut verifier = MockVerifier::new();
+        verifier
+            .expect_verify()
+            .returning(|_, _| Err("invalid".to_string()));
+
+        let certifier = Certifier {
+            verifier: Arc::new(verifier),
+            signer: SigningKey::generate(&mut rand::rngs::OsRng),
+            expiry: None,
+        };
+
+        let proof = Proof {
+            nonce: 0,
+            indices: std::borrow::Cow::Owned(vec![1, 2, 3]),
+            pow: 0,
+        };
+
+        let metadata = ProofMetadata {
+            node_id: [7; 32],
+            commitment_atx_id: [0u8; 32],
+            challenge: [0; 32],
+            num_units: 1,
+        };
+
+        certifier
+            .certify(&proof, &metadata)
+            .expect_err("certification should fail");
+    }
+
+    #[test]
+    fn ceritify_valid_post() {
+        let mut verifier = MockVerifier::new();
+        verifier.expect_verify().returning(|_, _| Ok(()));
+        let certifier = Certifier {
+            verifier: Arc::new(verifier),
+            signer: SigningKey::generate(&mut rand::rngs::OsRng),
+            expiry: None,
+        };
+
+        let proof = Proof {
+            nonce: 0,
+            indices: std::borrow::Cow::Owned(vec![1, 2, 3]),
+            pow: 0,
+        };
+
+        let metadata = ProofMetadata {
+            node_id: [7; 32],
+            commitment_atx_id: [0u8; 32],
+            challenge: [0; 32],
+            num_units: 1,
+        };
+
+        let (encoded, signature) = certifier
+            .certify(&proof, &metadata)
+            .expect("certification should succeed");
+
+        certifier
+            .signer
+            .verify(&encoded, &signature)
+            .expect("signature should be valid");
+
+        let cert = Certificate::decode(&mut encoded.as_slice())
+            .expect("decoding certificate should succeed");
+        assert!(cert.expiration.is_none());
+    }
+
+    #[test]
+    fn create_cert_with_expiry() {
+        let expiry = Duration::from_secs(60 * 60);
+        let certifier = Certifier {
+            verifier: Arc::new(MockVerifier::new()),
+            signer: SigningKey::generate(&mut rand::rngs::OsRng),
+            expiry: Some(expiry),
+        };
+
+        let started = SystemTime::now();
+        let cert = certifier.create_certificate(&[7u8; 32]);
+
+        let expiration = cert.expiration.unwrap().0;
+        assert!(expiration >= unix_timestamp(started + expiry));
+        assert!(expiration <= unix_timestamp(SystemTime::now() + expiry));
+    }
 }