use std::collections::BTreeSet;
use std::sync::Arc;
use std::sync::OnceLock;
use rustls::pki_types::pem::PemObject;
use rustls::pki_types::{CertificateDer, PrivateKeyDer, ServerName};
#[cfg(test)]
mod tests;
fn get_crypto_provider() -> Arc<rustls::crypto::CryptoProvider> {
static INSTANCE: OnceLock<Arc<rustls::crypto::CryptoProvider>> = OnceLock::new();
INSTANCE
.get_or_init(|| Arc::new(rustls::crypto::aws_lc_rs::default_provider()))
.clone()
}
fn get_supported_algorithms() -> rustls::crypto::WebPkiSupportedAlgorithms {
get_crypto_provider().signature_verification_algorithms
}
fn get_root_cert_store() -> Arc<rustls::RootCertStore> {
static INSTANCE: OnceLock<Arc<rustls::RootCertStore>> = OnceLock::new();
INSTANCE
.get_or_init(|| {
let root_store = rustls::RootCertStore {
roots: webpki_roots::TLS_SERVER_ROOTS.to_vec(),
};
Arc::new(root_store)
})
.clone()
}
fn create_client_config(
verify: bool,
client_cert: Option<(Vec<u8>, Vec<u8>)>,
server_fingerprints: Vec<String>,
) -> rustls::ClientConfig {
let builder = rustls::ClientConfig::builder_with_provider(get_crypto_provider())
.with_safe_default_protocol_versions()
.unwrap();
let builder = if verify {
let webpki_verifier = rustls::client::WebPkiServerVerifier::builder_with_provider(
get_root_cert_store(),
get_crypto_provider(),
)
.build()
.unwrap();
if !server_fingerprints.is_empty() {
builder
.dangerous()
.with_custom_certificate_verifier(Arc::new(ServerFingerprintVerifier {
supported_algs: get_supported_algorithms(),
server_fingerprints: process_fingerprints(&server_fingerprints).unwrap(),
webpki_verifier: Some(Arc::into_inner(webpki_verifier).unwrap()),
}))
} else {
builder.with_root_certificates(get_root_cert_store().clone())
}
} else if !server_fingerprints.is_empty() {
builder
.dangerous()
.with_custom_certificate_verifier(Arc::new(ServerFingerprintVerifier {
supported_algs: get_supported_algorithms(),
server_fingerprints: process_fingerprints(&server_fingerprints).unwrap(),
webpki_verifier: None,
}))
} else {
builder
.dangerous()
.with_custom_certificate_verifier(get_disabled_verifier())
};
if let Some((cert_bytes, key_bytes)) = client_cert {
let certs = load_certs(&cert_bytes);
let private_key = load_private_key(&key_bytes);
builder
.with_client_auth_cert(certs, private_key)
.expect("Could not parse client certificate")
} else {
builder.with_no_client_auth()
}
}
pub fn create_client_config_with_cert(
verify: bool,
client_cert: Option<(Vec<u8>, Vec<u8>)>,
alpn_protocols: Vec<Vec<u8>>,
enable_sni: bool,
server_fingerprints: Vec<String>,
) -> Arc<rustls::ClientConfig> {
let mut config = create_client_config(verify, client_cert, server_fingerprints);
config.alpn_protocols = alpn_protocols;
config.enable_sni = enable_sni;
Arc::new(config)
}
#[derive(Debug)]
pub struct DisabledVerifier {
supported_algs: rustls::crypto::WebPkiSupportedAlgorithms,
}
impl rustls::client::danger::ServerCertVerifier for DisabledVerifier {
fn verify_server_cert(
&self,
_end_entity: &CertificateDer<'_>,
_intermediates: &[CertificateDer<'_>],
_server_name: &ServerName<'_>,
_ocsp_response: &[u8],
_now: rustls::pki_types::UnixTime,
) -> Result<rustls::client::danger::ServerCertVerified, rustls::Error> {
Ok(rustls::client::danger::ServerCertVerified::assertion())
}
fn verify_tls12_signature(
&self,
message: &[u8],
cert: &CertificateDer<'_>,
dss: &rustls::DigitallySignedStruct,
) -> Result<rustls::client::danger::HandshakeSignatureValid, rustls::Error> {
rustls::crypto::verify_tls12_signature(message, cert, dss, &self.supported_algs)
}
fn verify_tls13_signature(
&self,
message: &[u8],
cert: &CertificateDer<'_>,
dss: &rustls::DigitallySignedStruct,
) -> Result<rustls::client::danger::HandshakeSignatureValid, rustls::Error> {
rustls::crypto::verify_tls13_signature(message, cert, dss, &self.supported_algs)
}
fn supported_verify_schemes(&self) -> Vec<rustls::SignatureScheme> {
self.supported_algs.supported_schemes()
}
}
fn get_disabled_verifier() -> Arc<DisabledVerifier> {
static INSTANCE: OnceLock<Arc<DisabledVerifier>> = OnceLock::new();
INSTANCE
.get_or_init(|| {
Arc::new(DisabledVerifier {
supported_algs: get_supported_algorithms(),
})
})
.clone()
}
#[derive(Debug)]
pub struct ServerFingerprintVerifier {
supported_algs: rustls::crypto::WebPkiSupportedAlgorithms,
server_fingerprints: BTreeSet<Vec<u8>>,
webpki_verifier: Option<rustls::client::WebPkiServerVerifier>,
}
impl rustls::client::danger::ServerCertVerifier for ServerFingerprintVerifier {
fn verify_server_cert(
&self,
end_entity: &CertificateDer<'_>,
intermediates: &[CertificateDer<'_>],
server_name: &ServerName<'_>,
ocsp_response: &[u8],
now: rustls::pki_types::UnixTime,
) -> Result<rustls::client::danger::ServerCertVerified, rustls::Error> {
if let Some(ref webpki_verifier) = self.webpki_verifier {
let _ = webpki_verifier.verify_server_cert(
end_entity,
intermediates,
server_name,
ocsp_response,
now,
)?;
}
let fingerprint =
aws_lc_rs::digest::digest(&aws_lc_rs::digest::SHA256, end_entity.as_ref());
let fingerprint_bytes = fingerprint.as_ref();
if self.server_fingerprints.contains(fingerprint_bytes) {
Ok(rustls::client::danger::ServerCertVerified::assertion())
} else {
let hex_fingerprint = fingerprint_bytes
.iter()
.map(|b| format!("{b:02x}"))
.collect::<Vec<String>>()
.join(":");
Err(rustls::Error::General(format!(
"unknown server fingerprint: {hex_fingerprint}"
)))
}
}
fn verify_tls12_signature(
&self,
message: &[u8],
cert: &CertificateDer<'_>,
dss: &rustls::DigitallySignedStruct,
) -> Result<rustls::client::danger::HandshakeSignatureValid, rustls::Error> {
rustls::crypto::verify_tls12_signature(message, cert, dss, &self.supported_algs)
}
fn verify_tls13_signature(
&self,
message: &[u8],
cert: &CertificateDer<'_>,
dss: &rustls::DigitallySignedStruct,
) -> Result<rustls::client::danger::HandshakeSignatureValid, rustls::Error> {
rustls::crypto::verify_tls13_signature(message, cert, dss, &self.supported_algs)
}
fn supported_verify_schemes(&self) -> Vec<rustls::SignatureScheme> {
self.supported_algs.supported_schemes()
}
}
pub fn load_certs(cert_bytes: &[u8]) -> Vec<CertificateDer<'static>> {
let certs: Vec<_> = CertificateDer::pem_slice_iter(cert_bytes)
.collect::<Result<_, _>>()
.unwrap();
if certs.is_empty() {
panic!("No certs found");
}
certs
}
pub fn load_private_key(key_bytes: &[u8]) -> PrivateKeyDer<'static> {
PrivateKeyDer::from_pem_slice(key_bytes).unwrap()
}
#[derive(Debug)]
struct AlwaysResolvesServerCert(Arc<rustls::sign::CertifiedKey>);
impl rustls::server::ResolvesServerCert for AlwaysResolvesServerCert {
fn resolve(
&self,
_client_hello: rustls::server::ClientHello,
) -> Option<Arc<rustls::sign::CertifiedKey>> {
Some(self.0.clone())
}
}
pub fn create_server_config(
certs: Vec<CertificateDer<'static>>,
private_key: &PrivateKeyDer<'static>,
alpn_protocols: Vec<Vec<u8>>,
client_fingerprints: &[String],
client_ca_certs: &[Vec<u8>],
) -> rustls::ServerConfig {
let signing_key = get_crypto_provider()
.key_provider
.load_private_key(private_key.clone_key())
.unwrap();
let certified_key = Arc::new(rustls::sign::CertifiedKey::new(certs, signing_key));
let webpki_verifier = if client_ca_certs.is_empty() {
None
} else {
let mut store = rustls::RootCertStore::empty();
for ca_bytes in client_ca_certs {
for cert in load_certs(ca_bytes) {
store.add(cert).unwrap();
}
}
Some(
rustls::server::WebPkiClientVerifier::builder_with_provider(
Arc::new(store),
get_crypto_provider(),
)
.build()
.unwrap(),
)
};
let builder = rustls::ServerConfig::builder_with_provider(get_crypto_provider())
.with_safe_default_protocol_versions()
.unwrap();
let builder = if client_fingerprints.is_empty() && webpki_verifier.is_none() {
builder.with_no_client_auth()
} else {
builder.with_client_cert_verifier(Arc::new(ClientFingerprintVerifier {
supported_algs: get_supported_algorithms(),
client_fingerprints: process_fingerprints(client_fingerprints).unwrap(),
webpki_verifier,
}))
};
let mut config = builder.with_cert_resolver(Arc::new(AlwaysResolvesServerCert(certified_key)));
config.alpn_protocols = alpn_protocols;
config.max_early_data_size = u32::MAX;
config.ignore_client_order = true;
config
}
pub fn get_dummy_server_name() -> ServerName<'static> {
static INSTANCE: OnceLock<ServerName<'static>> = OnceLock::new();
INSTANCE
.get_or_init(|| ServerName::try_from("example.com").unwrap().to_owned())
.clone()
}
pub fn process_fingerprints(client_fingerprints: &[String]) -> std::io::Result<BTreeSet<Vec<u8>>> {
let mut result = BTreeSet::new();
for fingerprint in client_fingerprints {
let clean_fp = fingerprint.replace(":", "").replace(" ", "");
if clean_fp.len() % 2 != 0 {
return Err(std::io::Error::new(
std::io::ErrorKind::InvalidInput,
format!("Invalid client fingerprint, odd number of hex chars: {fingerprint}"),
));
}
let bytes = (0..clean_fp.len())
.step_by(2)
.map(|i| u8::from_str_radix(&clean_fp[i..i + 2], 16))
.collect::<Result<Vec<u8>, _>>()
.map_err(|_| {
std::io::Error::new(
std::io::ErrorKind::InvalidInput,
format!("Invalid client fingerprint, could not convert to hex: {fingerprint}"),
)
})?;
result.insert(bytes);
}
Ok(result)
}
#[derive(Debug)]
pub struct ClientFingerprintVerifier {
supported_algs: rustls::crypto::WebPkiSupportedAlgorithms,
client_fingerprints: BTreeSet<Vec<u8>>,
webpki_verifier: Option<Arc<dyn rustls::server::danger::ClientCertVerifier>>,
}
impl rustls::server::danger::ClientCertVerifier for ClientFingerprintVerifier {
fn offer_client_auth(&self) -> bool {
true
}
fn client_auth_mandatory(&self) -> bool {
true
}
fn root_hint_subjects(&self) -> &[rustls::DistinguishedName] {
&[]
}
fn verify_client_cert(
&self,
end_entity: &CertificateDer<'_>,
intermediates: &[CertificateDer<'_>],
now: rustls::pki_types::UnixTime,
) -> Result<rustls::server::danger::ClientCertVerified, rustls::Error> {
if let Some(ref webpki_verifier) = self.webpki_verifier {
if webpki_verifier
.verify_client_cert(end_entity, intermediates, now)
.is_ok()
{
return Ok(rustls::server::danger::ClientCertVerified::assertion());
}
}
let fingerprint =
aws_lc_rs::digest::digest(&aws_lc_rs::digest::SHA256, end_entity.as_ref());
let fingerprint_bytes = fingerprint.as_ref();
if self.client_fingerprints.contains(fingerprint_bytes) {
Ok(rustls::server::danger::ClientCertVerified::assertion())
} else {
let hex_fingerprint = fingerprint_bytes
.iter()
.map(|b| format!("{b:02x}"))
.collect::<Vec<String>>()
.join(":");
Err(rustls::Error::General(format!(
"unknown client fingerprint: {hex_fingerprint}"
)))
}
}
fn verify_tls12_signature(
&self,
message: &[u8],
cert: &CertificateDer<'_>,
dss: &rustls::DigitallySignedStruct,
) -> Result<rustls::client::danger::HandshakeSignatureValid, rustls::Error> {
rustls::crypto::verify_tls12_signature(message, cert, dss, &self.supported_algs)
}
fn verify_tls13_signature(
&self,
message: &[u8],
cert: &CertificateDer<'_>,
dss: &rustls::DigitallySignedStruct,
) -> Result<rustls::client::danger::HandshakeSignatureValid, rustls::Error> {
rustls::crypto::verify_tls13_signature(message, cert, dss, &self.supported_algs)
}
fn supported_verify_schemes(&self) -> Vec<rustls::SignatureScheme> {
self.supported_algs.supported_schemes()
}
}