Fix get-tls-cert to accept custom CA and gracefully close connection

src/lib.rs

@@ -189,6 +189,8 @@ impl ProxyServer {
         attestation_generator: AttestationGenerator,
         attestation_verifier: AttestationVerifier,
     ) -> Result<(), ProxyError> {
+        tracing::debug!("proxy-server accepted connection");
+
         // Do TLS handshake
         let mut tls_stream = acceptor.accept(inbound).await?;
         let (_io, connection) = tls_stream.get_ref();
@@ -524,6 +526,8 @@ impl ProxyClient {
         inbound: TcpStream,
         requests_tx: mpsc::Sender<RequestWithResponseSender>,
     ) -> Result<(), ProxyError> {
+        tracing::debug!("proxy-client accepted connection");
+
         // Setup http server and handler
         let http = hyper::server::conn::http1::Builder::new();
         let service = service_fn(move |req| {
@@ -688,11 +692,28 @@ impl ProxyClient {
 pub async fn get_tls_cert(
     server_name: String,
     attestation_verifier: AttestationVerifier,
+    remote_certificate: Option<CertificateDer<'_>>,
 ) -> Result<Vec<CertificateDer<'static>>, ProxyError> {
-    let root_store = RootCertStore::from_iter(webpki_roots::TLS_SERVER_ROOTS.iter().cloned());
-    let client_config = ClientConfig::builder()
+    tracing::debug!("Getting remote TLS cert");
+    // If a remote CA cert was given, use it as the root store, otherwise use webpki_roots
+    let root_store = match remote_certificate {
+        Some(remote_certificate) => {
+            let mut root_store = RootCertStore::empty();
+            root_store.add(remote_certificate)?;
+            root_store
+        }
+        None => RootCertStore::from_iter(webpki_roots::TLS_SERVER_ROOTS.iter().cloned()),
+    };
+
+    let mut client_config = ClientConfig::builder()
         .with_root_certificates(root_store)
         .with_no_client_auth();
+
+    client_config.alpn_protocols = SUPPORTED_ALPN_PROTOCOL_VERSIONS
+        .into_iter()
+        .map(|p| p.to_vec())
+        .collect();
+
     get_tls_cert_with_config(server_name, attestation_verifier, client_config.into()).await
 }
 
@@ -737,6 +758,8 @@ async fn get_tls_cert_with_config(
         .verify_attestation(remote_attestation_message, remote_input_data)
         .await?;
 
+    tls_stream.shutdown().await?;
+
     Ok(remote_cert_chain)
 }
 

src/main.rs

@@ -78,7 +78,7 @@ enum CliCommand {
         /// The path to a PEM encoded private key
         #[arg(long, env = "TLS_PRIVATE_KEY_PATH")]
         tls_private_key_path: PathBuf,
-        /// The path to a PEM encoded certificate chain
+        /// Additional CA certificate to verify against (PEM) Defaults to no additional TLS certs.
         #[arg(long, env = "TLS_CERTIFICATE_PATH")]
         tls_certificate_path: PathBuf,
         /// Whether to use client authentication. If the client is running in a CVM this must be
@@ -99,6 +99,9 @@ enum CliCommand {
     GetTlsCert {
         /// The hostname:port or ip:port of the proxy server (port defaults to 443)
         server: String,
+        /// Additional CA certificate to verify against (PEM) Defaults to no additional TLS certs.
+        #[arg(long)]
+        tls_ca_certificate: Option<PathBuf>,
     },
     /// Serve a filesystem path over an attested channel
     AttestedFileServer {
@@ -114,7 +117,7 @@ enum CliCommand {
         /// The path to a PEM encoded private key
         #[arg(long, env = "TLS_PRIVATE_KEY_PATH")]
         tls_private_key_path: PathBuf,
-        /// The path to a PEM encoded certificate chain
+        /// Additional CA certificate to verify against (PEM) Defaults to no additional TLS certs.
         #[arg(long, env = "TLS_CERTIFICATE_PATH")]
         tls_certificate_path: PathBuf,
         /// URL of the remote dummy attestation service. Only use with --server-attestation-type
@@ -145,7 +148,7 @@ async fn main() -> anyhow::Result<()> {
         "Exactly one of --measurements-file or --allowed-remote-attestation-type must be provided"
     );
 
-    let crate_name = env!("CARGO_PKG_NAME");
+    let crate_name = env!("CARGO_CRATE_NAME");
 
     let env_filter = tracing_subscriber::EnvFilter::builder()
         .with_default_directive(LevelFilter::WARN.into()) // global default
@@ -281,8 +284,20 @@ async fn main() -> anyhow::Result<()> {
                 }
             }
         }
-        CliCommand::GetTlsCert { server } => {
-            let cert_chain = get_tls_cert(server, attestation_verifier).await?;
+        CliCommand::GetTlsCert {
+            server,
+            tls_ca_certificate,
+        } => {
+            let remote_tls_cert = match tls_ca_certificate {
+                Some(remote_cert_filename) => Some(
+                    load_certs_pem(remote_cert_filename)?
+                        .first()
+                        .ok_or(anyhow!("Filename given but no ceritificates found"))?
+                        .clone(),
+                ),
+                None => None,
+            };
+            let cert_chain = get_tls_cert(server, attestation_verifier, remote_tls_cert).await?;
             println!("{}", certs_to_pem_string(&cert_chain)?);
         }
         CliCommand::AttestedFileServer {