feat(transport): added support for EC keys (#1145)

* tonic: allow TLS to read ECKeys.

Fixes: #1143
Signed-off-by: Yu Juncen <yu745514916@live.com>

* tonic: minimize the scope of published function.

Signed-off-by: Yu Juncen <yu745514916@live.com>

---------

Signed-off-by: Yu Juncen <yu745514916@live.com>

Author: YuJuncen

tonic/src/transport/service/tls.rs

@@ -178,21 +178,15 @@ mod rustls_keys {
     use crate::transport::service::tls::TlsError;
     use crate::transport::Identity;
 
-    fn load_rustls_private_key(
+    pub(super) fn load_rustls_private_key(
         mut cursor: std::io::Cursor<&[u8]>,
     ) -> Result<PrivateKey, crate::Error> {
-        // First attempt to load the private key assuming it is PKCS8-encoded
-        if let Ok(mut keys) = rustls_pemfile::pkcs8_private_keys(&mut cursor) {
-            if let Some(key) = keys.pop() {
-                return Ok(PrivateKey(key));
-            }
-        }
-
-        // If it not, try loading the private key as an RSA key
-        cursor.set_position(0);
-        if let Ok(mut keys) = rustls_pemfile::rsa_private_keys(&mut cursor) {
-            if let Some(key) = keys.pop() {
-                return Ok(PrivateKey(key));
+        while let Ok(Some(item)) = rustls_pemfile::read_one(&mut cursor) {
+            match item {
+                rustls_pemfile::Item::RSAKey(key)
+                | rustls_pemfile::Item::PKCS8Key(key)
+                | rustls_pemfile::Item::ECKey(key) => return Ok(PrivateKey(key)),
+                _ => continue,
             }
         }
 
@@ -235,3 +229,78 @@ mod rustls_keys {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use std::io::Cursor;
+
+    // generated by: openssl ecparam -keygen -name 'prime256v1'
+    const SIMPLE_EC_KEY: &str = r#"-----BEGIN EC PARAMETERS-----
+BggqhkjOPQMBBw==
+-----END EC PARAMETERS-----
+-----BEGIN EC PRIVATE KEY-----
+MHcCAQEEICIDyh40kMVWGDAYr1gXnMfeMeO3zXYigOaWrg5SNB+zoAoGCCqGSM49
+AwEHoUQDQgAEacJyVg299dkPTzUaMbOmACUfF67yp+ZrDhXVjn/5WxBAgjcmFBHg
+Tw8dfwpMzaJPXX5lWYzP276fcmbRO25CXw==
+-----END EC PRIVATE KEY-----"#;
+
+    // generated by: openssl genpkey -algorithm rsa
+    const SIMPLE_PKCS8_KEY: &str = r#"-----BEGIN PRIVATE KEY-----
+MIICdwIBADANBgkqhkiG9w0BAQEFAASCAmEwggJdAgEAAoGBAKHkX1YIvqOIAllD
+5fKcIxu2kYjIxxAAQrOBRTloGZUKdPFQY1RANB4t/LEaI5/NJ6NK4915pTn35QAQ
+zHJl+X4rNFMgVt+o/nY40PgrQxyyv5A0/URp+iS8Yn3GKt3q6p4zguiO9uNXhiiD
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+G7X4Bb6X8vrVSMrfze2loT0aNri9jKDZkD/muy6+9JkhRa03NOdhDdseokmcqF3L
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+sswXAkBDYDtb19E/cox4MTg5DfwpMJrwmAYufCqi4Uq4uiI++/SanVKc57jaqbvA
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+peOO6Yadu0YbSmFNluRebia6410p5jR21LhG1ty2h22xVhlBWjOC+TyDuKwhmiYT
+ed50S3LR1PWt4zE=
+-----END PRIVATE KEY-----"#;
+
+    // generated by: openssl genrsa
+    const SIMPLE_RSA_KEY: &str = r#"-----BEGIN RSA PRIVATE KEY-----
+MIIEogIBAAKCAQEAoEILGds1/RGBHT7jM4R+EL24sQ6Bsn14GgTHc7WoZ7lainEH
+H/n+DtHCYUXYyJnN5AMIi3pkigCP1hdXXBQga3zs3lXoi/mAMkT6vjuqQ7Xg5/95
+ABx5Ztyy25mZNaXm77glyAzSscKHxWYooXVJYG4C3SGuBJJ1zVjxen6Rkzse5Lpr
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+N7Im/uReh8F8So57W0aRmZCmFMnVFEp7LZsp41RQKnzRgqo+EYoU/l0MWk27t4wS
+WR5pz9KwKsPnV9poydgl/eKRSq0THQ9PgM7v0BoWw2iTk6g1DCivPFw4G6wL/5uo
+MozHZXFsjaaaUREktokO6QKBgC3Dg7RILtqaoIOYH+9OseJz4cU+CWyc7XpZKuHv
+nO/YbkCAh8syyojrjmEzUz66umwx+t3KubhFBSxZx/nVB9EYkWiKOEdeBxY2tjLa
+F3qLXXojK7GGtBrEbLE3UizU47jD/3xlLO59NXWzgFygwR4p1vnH2EWJaV7fs4lZ
+OWPRAoGAL0nX0vZ0N9qPETiQan1uHjKYuuFiSP+cwRXVSUYIQM9qDRlKG9zjugwO
+az+B6uiR4TrgbwG+faCQwcGk9B8QbcoIb8IigwrWe3XpVaEtcsqFORX0r+tJNDoY
+I0O2DOQVPKSK2N5AZzXY4IkybWTV4Yxc7rdXEO3dOOpHGKbpwFQ=
+-----END RSA PRIVATE KEY-----"#;
+
+    #[test]
+    fn test_parse_ec_key() {
+        for (n, key) in [SIMPLE_EC_KEY, SIMPLE_PKCS8_KEY, SIMPLE_RSA_KEY]
+            .iter()
+            .enumerate()
+        {
+            let c = Cursor::new(key.as_bytes());
+            let key = super::rustls_keys::load_rustls_private_key(c);
+
+            assert!(key.is_ok(), "at the {}-th case", n);
+        }
+    }
+}