Expand Shadowsocks runtime compatibility

third_party/rustls-fork-shadow-tls/src/key_log.rs

@@ -0,0 +1,55 @@
+/// This trait represents the ability to do something useful
+/// with key material, such as logging it to a file for debugging.
+///
+/// Naturally, secrets passed over the interface are *extremely*
+/// sensitive and can break the security of past, present and
+/// future sessions.
+///
+/// You'll likely want some interior mutability in your
+/// implementation to make this useful.
+///
+/// See [`KeyLogFile`](crate::KeyLogFile) that implements the standard
+/// `SSLKEYLOGFILE` environment variable behaviour.
+pub trait KeyLog: Send + Sync {
+    /// Log the given `secret`.  `client_random` is provided for
+    /// session identification.  `label` describes precisely what
+    /// `secret` means:
+    ///
+    /// - `CLIENT_RANDOM`: `secret` is the master secret for a TLSv1.2 session.
+    /// - `CLIENT_EARLY_TRAFFIC_SECRET`: `secret` encrypts early data
+    ///   transmitted by a client
+    /// - `SERVER_HANDSHAKE_TRAFFIC_SECRET`: `secret` encrypts
+    ///   handshake messages from the server during a TLSv1.3 handshake.
+    /// - `CLIENT_HANDSHAKE_TRAFFIC_SECRET`: `secret` encrypts
+    ///   handshake messages from the client during a TLSv1.3 handshake.
+    /// - `SERVER_TRAFFIC_SECRET_0`: `secret` encrypts post-handshake data
+    ///   from the server in a TLSv1.3 session.
+    /// - `CLIENT_TRAFFIC_SECRET_0`: `secret` encrypts post-handshake data
+    ///   from the client in a TLSv1.3 session.
+    /// - `EXPORTER_SECRET`: `secret` is the post-handshake exporter secret
+    ///   in a TLSv1.3 session.
+    ///
+    /// These strings are selected to match the NSS key log format:
+    /// <https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/Key_Log_Format>
+    fn log(&self, label: &str, client_random: &[u8], secret: &[u8]);
+
+    /// Indicates whether the secret with label `label` will be logged.
+    ///
+    /// If `will_log` returns true then `log` will be called with the secret.
+    /// Otherwise, `log` will not be called for the secret. This is a
+    /// performance optimization.
+    fn will_log(&self, _label: &str) -> bool {
+        true
+    }
+}
+
+/// KeyLog that does exactly nothing.
+pub struct NoKeyLog;
+
+impl KeyLog for NoKeyLog {
+    fn log(&self, _: &str, _: &[u8], _: &[u8]) {}
+    #[inline]
+    fn will_log(&self, _label: &str) -> bool {
+        false
+    }
+}