feat: Implement accept_invalid_hostnames for rustls

CHANGELOG.md

@@ -1,3 +1,7 @@
+## Unreleased
+
+- Implement `danger_accept_invalid_hostnames` for `rustls`.
+
 ## v0.12.5
 
 - Add `blocking::ClientBuilder::dns_resolver()` method to change DNS resolver in blocking client.

src/async_impl/client.rs

@@ -91,7 +91,7 @@ struct Config {
     // NOTE: When adding a new field, update `fmt::Debug for ClientBuilder`
     accepts: Accepts,
     headers: HeaderMap,
-    #[cfg(feature = "native-tls")]
+    #[cfg(feature = "__tls")]
     hostname_verification: bool,
     #[cfg(feature = "__tls")]
     certs_verification: bool,
@@ -188,7 +188,7 @@ impl ClientBuilder {
                 error: None,
                 accepts: Accepts::default(),
                 headers,
-                #[cfg(feature = "native-tls")]
+                #[cfg(feature = "__tls")]
                 hostname_verification: true,
                 #[cfg(feature = "__tls")]
                 certs_verification: true,
@@ -388,10 +388,7 @@ impl ClientBuilder {
                         }
                     }
 
-                    #[cfg(feature = "native-tls")]
-                    {
-                        tls.danger_accept_invalid_hostnames(!config.hostname_verification);
-                    }
+                    tls.danger_accept_invalid_hostnames(!config.hostname_verification);
 
                     tls.danger_accept_invalid_certs(!config.certs_verification);
 
@@ -500,7 +497,7 @@ impl ClientBuilder {
                 }
                 #[cfg(feature = "__rustls")]
                 TlsBackend::Rustls => {
-                    use crate::tls::NoVerifier;
+                    use crate::tls::{IgnoreHostname, NoVerifier};
 
                     // Set root certificates.
                     let mut root_cert_store = rustls::RootCertStore::empty();
@@ -578,10 +575,25 @@ impl ClientBuilder {
                         });
 
                     // Build TLS config
+                    let signature_algorithms = provider.signature_verification_algorithms;
                     let config_builder = rustls::ClientConfig::builder_with_provider(provider)
                         .with_protocol_versions(&versions)
-                        .map_err(|_| crate::error::builder("invalid TLS versions"))?
-                        .with_root_certificates(root_cert_store);
+                        .map_err(|_| crate::error::builder("invalid TLS versions"))?;
+
+                    let config_builder = if !config.certs_verification {
+                        config_builder
+                            .dangerous()
+                            .with_custom_certificate_verifier(Arc::new(NoVerifier))
+                    } else if !config.hostname_verification {
+                        config_builder
+                            .dangerous()
+                            .with_custom_certificate_verifier(Arc::new(IgnoreHostname::new(
+                                root_cert_store,
+                                signature_algorithms,
+                            )))
+                    } else {
+                        config_builder.with_root_certificates(root_cert_store)
+                    };
 
                     // Finalize TLS config
                     let mut tls = if let Some(id) = config.identity {
@@ -590,12 +602,6 @@ impl ClientBuilder {
                         config_builder.with_no_client_auth()
                     };
 
-                    // Certificate verifier
-                    if !config.certs_verification {
-                        tls.dangerous()
-                            .set_certificate_verifier(Arc::new(NoVerifier));
-                    }
-
                     tls.enable_sni = config.tls_sni;
 
                     // ALPN protocol
@@ -1476,9 +1482,17 @@ impl ClientBuilder {
     ///
     /// # Optional
     ///
-    /// This requires the optional `native-tls` feature to be enabled.
-    #[cfg(feature = "native-tls")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "native-tls")))]
+    /// This requires the optional `default-tls`, `native-tls`, or `rustls-tls(-...)`
+    /// feature to be enabled.
+    #[cfg(feature = "__tls")]
+    #[cfg_attr(
+        docsrs,
+        doc(cfg(any(
+            feature = "default-tls",
+            feature = "native-tls",
+            feature = "rustls-tls"
+        )))
+    )]
     pub fn danger_accept_invalid_hostnames(
         mut self,
         accept_invalid_hostname: bool,
@@ -2243,7 +2257,7 @@ impl Config {
             f.field("tcp_nodelay", &true);
         }
 
-        #[cfg(feature = "native-tls")]
+        #[cfg(feature = "__tls")]
         {
             if !self.hostname_verification {
                 f.field("danger_accept_invalid_hostnames", &true);

src/blocking/client.rs

@@ -670,9 +670,17 @@ impl ClientBuilder {
     ///
     /// # Optional
     ///
-    /// This requires the optional `native-tls` feature to be enabled.
-    #[cfg(feature = "native-tls")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "native-tls")))]
+    /// This requires the optional `default-tls`, `native-tls`, or `rustls-tls(-...)`
+    /// feature to be enabled.
+    #[cfg(feature = "__tls")]
+    #[cfg_attr(
+        docsrs,
+        doc(cfg(any(
+            feature = "default-tls",
+            feature = "native-tls",
+            feature = "rustls-tls"
+        )))
+    )]
     pub fn danger_accept_invalid_hostnames(self, accept_invalid_hostname: bool) -> ClientBuilder {
         self.with_inner(|inner| inner.danger_accept_invalid_hostnames(accept_invalid_hostname))
     }

src/tls.rs

@@ -47,7 +47,9 @@
 #[cfg(feature = "__rustls")]
 use rustls::{
     client::danger::HandshakeSignatureValid, client::danger::ServerCertVerified,
-    client::danger::ServerCertVerifier, DigitallySignedStruct, Error as TLSError, SignatureScheme,
+    client::danger::ServerCertVerifier, crypto::WebPkiSupportedAlgorithms,
+    server::ParsedCertificate, DigitallySignedStruct, Error as TLSError, RootCertStore,
+    SignatureScheme,
 };
 #[cfg(feature = "__rustls")]
 use rustls_pki_types::{ServerName, UnixTime};
@@ -571,6 +573,71 @@ impl ServerCertVerifier for NoVerifier {
     }
 }
 
+#[cfg(feature = "__rustls")]
+#[derive(Debug)]
+pub(crate) struct IgnoreHostname {
+    roots: RootCertStore,
+    signature_algorithms: WebPkiSupportedAlgorithms,
+}
+
+#[cfg(feature = "__rustls")]
+impl IgnoreHostname {
+    pub(crate) fn new(
+        roots: RootCertStore,
+        signature_algorithms: WebPkiSupportedAlgorithms,
+    ) -> Self {
+        Self {
+            roots,
+            signature_algorithms,
+        }
+    }
+}
+
+#[cfg(feature = "__rustls")]
+impl ServerCertVerifier for IgnoreHostname {
+    fn verify_server_cert(
+        &self,
+        end_entity: &rustls_pki_types::CertificateDer<'_>,
+        intermediates: &[rustls_pki_types::CertificateDer<'_>],
+        _server_name: &ServerName<'_>,
+        _ocsp_response: &[u8],
+        now: UnixTime,
+    ) -> Result<ServerCertVerified, TLSError> {
+        let cert = ParsedCertificate::try_from(end_entity)?;
+
+        rustls::client::verify_server_cert_signed_by_trust_anchor(
+            &cert,
+            &self.roots,
+            intermediates,
+            now,
+            self.signature_algorithms.all,
+        )?;
+        Ok(ServerCertVerified::assertion())
+    }
+
+    fn verify_tls12_signature(
+        &self,
+        message: &[u8],
+        cert: &rustls_pki_types::CertificateDer<'_>,
+        dss: &DigitallySignedStruct,
+    ) -> Result<HandshakeSignatureValid, TLSError> {
+        rustls::crypto::verify_tls12_signature(message, cert, dss, &self.signature_algorithms)
+    }
+
+    fn verify_tls13_signature(
+        &self,
+        message: &[u8],
+        cert: &rustls_pki_types::CertificateDer<'_>,
+        dss: &DigitallySignedStruct,
+    ) -> Result<HandshakeSignatureValid, TLSError> {
+        rustls::crypto::verify_tls13_signature(message, cert, dss, &self.signature_algorithms)
+    }
+
+    fn supported_verify_schemes(&self) -> Vec<SignatureScheme> {
+        self.signature_algorithms.supported_schemes()
+    }
+}
+
 /// Hyper extension carrying extra TLS layer information.
 /// Made available to clients on responses when `tls_info` is set.
 #[derive(Clone)]

tests/badssl.rs

@@ -75,7 +75,7 @@ async fn test_badssl_no_built_in_roots() {
     assert!(result.is_err());
 }
 
-#[cfg(feature = "native-tls")]
+#[cfg(any(feature = "native-tls", feature = "rustls-tls"))]
 #[tokio::test]
 async fn test_badssl_wrong_host() {
     let text = reqwest::Client::builder()