[rustls] identity: handle elliptic curve private keys

This commit improves the user experience of the users leveraging rustls.

When building the identity to use for requests, it's now possible to use
also private keys using Elliptic Curve that are encoded with SEC1
standard.

This is the default encoding used by openssl when EC keys are created.
Prior to this commit users had to convert those keys from the SEC1
encoding to the PKCS 8 one, which is something not trivial.

This feature has been recently added to rustls-pemfile crate.

Signed-off-by: Flavio Castelli <fcastelli@suse.com>

src/tls.rs

@@ -184,7 +184,7 @@ impl Identity {
     /// The input should contain a PEM encoded private key
     /// and at least one PEM encoded certificate.
     ///
-    /// Note: The private key must be in RSA or PKCS#8 format.
+    /// Note: The private key must be in RSA, SEC1 Elliptic Curve or PKCS#8 format.
     ///
     /// # Examples
     ///
@@ -210,33 +210,29 @@ impl Identity {
 
         let (key, certs) = {
             let mut pem = Cursor::new(buf);
-            let certs = rustls_pemfile::certs(&mut pem)
-                .map_err(|_| TLSError::General(String::from("No valid certificate was found")))
-                .map_err(crate::error::builder)?
-                .into_iter()
-                .map(rustls::Certificate)
-                .collect::<Vec<_>>();
-            pem.set_position(0);
-            let mut sk = rustls_pemfile::pkcs8_private_keys(&mut pem)
-                .and_then(|pkcs8_keys| {
-                    if pkcs8_keys.is_empty() {
-                        Err(std::io::Error::new(
-                            std::io::ErrorKind::NotFound,
-                            "No valid private key was found",
-                        ))
-                    } else {
-                        Ok(pkcs8_keys)
+            let mut sk = Vec::<rustls::PrivateKey>::new();
+            let mut certs = Vec::<rustls::Certificate>::new();
+
+            for item in std::iter::from_fn(|| rustls_pemfile::read_one(&mut pem).transpose()) {
+                match item.map_err(|_| {
+                    crate::error::builder(TLSError::General(String::from(
+                        "Invalid identity PEM file",
+                    )))
+                })? {
+                    rustls_pemfile::Item::X509Certificate(cert) => {
+                        certs.push(rustls::Certificate(cert))
+                    }
+                    rustls_pemfile::Item::PKCS8Key(key) => sk.push(rustls::PrivateKey(key)),
+                    rustls_pemfile::Item::RSAKey(key) => sk.push(rustls::PrivateKey(key)),
+                    rustls_pemfile::Item::ECKey(key) => sk.push(rustls::PrivateKey(key)),
+                    _ => {
+                        return Err(crate::error::builder(TLSError::General(String::from(
+                            "No valid certificate was found",
+                        ))))
                     }
-                })
-                .or_else(|_| {
-                    pem.set_position(0);
-                    rustls_pemfile::rsa_private_keys(&mut pem)
-                })
-                .map_err(|_| TLSError::General(String::from("No valid private key was found")))
-                .map_err(crate::error::builder)?
-                .into_iter()
-                .map(rustls::PrivateKey)
-                .collect::<Vec<_>>();
+                }
+            }
+
             if let (Some(sk), false) = (sk.pop(), certs.is_empty()) {
                 (sk, certs)
             } else {