rustls/
key_log.rs

1use core::fmt::Debug;
2
3/// This trait represents the ability to do something useful
4/// with key material, such as logging it to a file for debugging.
5///
6/// Naturally, secrets passed over the interface are *extremely*
7/// sensitive and can break the security of past, present and
8/// future sessions.
9///
10/// You'll likely want some interior mutability in your
11/// implementation to make this useful.
12///
13/// For the standard `SSLKEYLOGFILE` environment variable behavior,
14/// see the `KeyLogFile` implementation provided in the rustls-util crate.
15///
16/// See <https://datatracker.ietf.org/doc/html/rfc9850> for more background
17/// information.
18pub trait KeyLog: Debug + Send + Sync {
19    /// Log the given `secret`.  `client_random` is provided for
20    /// session identification.  `label` describes precisely what
21    /// `secret` means:
22    ///
23    /// - `CLIENT_RANDOM`: `secret` is the master secret for a TLSv1.2 session.
24    /// - `CLIENT_EARLY_TRAFFIC_SECRET`: `secret` encrypts early data
25    ///   transmitted by a client
26    /// - `SERVER_HANDSHAKE_TRAFFIC_SECRET`: `secret` encrypts
27    ///   handshake messages from the server during a TLSv1.3 handshake.
28    /// - `CLIENT_HANDSHAKE_TRAFFIC_SECRET`: `secret` encrypts
29    ///   handshake messages from the client during a TLSv1.3 handshake.
30    /// - `SERVER_TRAFFIC_SECRET_0`: `secret` encrypts post-handshake data
31    ///   from the server in a TLSv1.3 session.
32    /// - `CLIENT_TRAFFIC_SECRET_0`: `secret` encrypts post-handshake data
33    ///   from the client in a TLSv1.3 session.
34    /// - `EXPORTER_SECRET`: `secret` is the post-handshake exporter secret
35    ///   in a TLSv1.3 session.
36    ///
37    /// These strings are standardised by IANA:
38    /// <https://www.iana.org/assignments/tls-parameters#tls-sslkeylogfile-labels>
39    fn log(&self, label: &str, client_random: &[u8], secret: &[u8]);
40
41    /// Indicates whether the secret with label `label` will be logged.
42    ///
43    /// If `will_log` returns true then `log` will be called with the secret.
44    /// Otherwise, `log` will not be called for the secret. This is a
45    /// performance optimization.
46    fn will_log(&self, _label: &str) -> bool {
47        true
48    }
49}
50
51/// KeyLog that does exactly nothing.
52#[expect(clippy::exhaustive_structs)]
53#[derive(Debug)]
54pub struct NoKeyLog;
55
56impl KeyLog for NoKeyLog {
57    fn log(&self, _: &str, _: &[u8], _: &[u8]) {}
58    #[inline]
59    fn will_log(&self, _label: &str) -> bool {
60        false
61    }
62}
rustls/key_log.rs

rustls/
key_log.rs
