support reading EC private key

src/pem_util.rs

@@ -1,6 +1,8 @@
+use anyhow::bail;
 use anyhow::Context;
 use anyhow::Result;
 use rustls::{Certificate, PrivateKey};
+use rustls_pemfile::Item;
 use std::{fs::File, io::BufReader};
 
 pub fn load_certificates_from_pem(path: &str) -> Result<Vec<Certificate>> {
@@ -13,12 +15,13 @@ pub fn load_certificates_from_pem(path: &str) -> Result<Vec<Certificate>> {
 pub fn load_private_key_from_pem(path: &str) -> Result<PrivateKey> {
     let file = File::open(path)?;
     let mut reader = BufReader::new(&file);
-    let mut keys = rustls_pemfile::pkcs8_private_keys(&mut reader)?;
-    if keys.is_empty() {
-        let mut reader = BufReader::new(&file);
-        keys = rustls_pemfile::rsa_private_keys(&mut reader)?;
-    }
 
-    let first_key = keys.first().context("failed to load private key")?;
-    Ok(PrivateKey(first_key.to_owned()))
+    let key = match rustls_pemfile::read_one(&mut reader).context("failed to read private key")? {
+        Some(Item::RSAKey(key)) => key,
+        Some(Item::PKCS8Key(key)) => key,
+        Some(Item::ECKey(key)) => key,
+        _ => bail!("unexpected private key"),
+    };
+
+    Ok(PrivateKey(key.to_owned()))
 }