From eccf90a5343cbc093eb94f0fc9d0bc0778117613 Mon Sep 17 00:00:00 2001
From: Brian Smith <brian@briansmith.org>
Date: Mon, 28 Aug 2017 18:40:16 -1000
Subject: [PATCH] Remove `danger` feature & the API it controls.

The singular purpose of this crate should be to integrate Tokio and
Rustls. Therefore, any feature that isn't about making Rustls work
nicely with Tokio should be assumed a priori to be out of scope.

In particular, it is out of scope for tokio-rustls to provide APIs to
control SNI behavior. Instead, the application should configure
Rustls's SNI behavior using Rustls's configuration APIs, and pass the
configuration to tokio-rustls. Similarly, it is out of scope for
tokio-rustls to provide APIs to control the certificate validation
behavior. Instead, the application should configure certificate
validation using Rustls's APIs. Perhaps there should be a crate that
makes it convenient to do "dangerous" certificate validation, but IMO
that shouldn't be tokio-rustls, but a different one.

FWIW, the `danger` API was inherited from tokio-tls, and I'm working on
making an analogous change there.
---
 Cargo.toml    |  3 ---
 src/lib.rs    | 29 -----------------------------
 tests/test.rs | 21 ++++-----------------
 3 files changed, 4 insertions(+), 49 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 796d24f..a739599 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -14,9 +14,6 @@ categories = ["asynchronous", "cryptography", "network-programming"]
 travis-ci = { repository = "quininer/tokio-rustls" }
 appveyor = { repository = "quininer/tokio-rustls" }
 
-[features]
-danger = [ "rustls/dangerous_configuration" ]
-
 [dependencies]
 futures = "0.1"
 tokio-io = "0.1"
diff --git a/src/lib.rs b/src/lib.rs
index 978eb6c..12cdf53 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -22,11 +22,6 @@ pub trait ClientConfigExt {
     fn connect_async<S>(&self, domain: &str, stream: S)
         -> ConnectAsync<S>
         where S: AsyncRead + AsyncWrite;
-
-    #[cfg(feature = "danger")]
-    fn danger_connect_async_without_providing_domain_for_certificate_verification_and_server_name_indication<S>(&self, stream: S)
-        -> ConnectAsync<S>
-        where S: AsyncRead + AsyncWrite;
 }
 
 /// Extension trait for the `Arc<ServerConfig>` type in the `rustls` crate.
@@ -53,30 +48,6 @@ impl ClientConfigExt for Arc<ClientConfig> {
     {
         connect_async_with_session(stream, ClientSession::new(self, domain))
     }
-
-    #[cfg(feature = "danger")]
-    fn danger_connect_async_without_providing_domain_for_certificate_verification_and_server_name_indication<S>(&self, stream: S)
-        -> ConnectAsync<S>
-        where S: AsyncRead + AsyncWrite
-    {
-        use rustls::{ ServerCertVerifier, RootCertStore, Certificate, ServerCertVerified, TLSError };
-
-        struct NoCertVerifier;
-        impl ServerCertVerifier for NoCertVerifier {
-            fn verify_server_cert(&self, _: &RootCertStore, _: &[Certificate], _: &str, _: &[u8])
-                -> Result<ServerCertVerified, TLSError>
-            {
-                Ok(ServerCertVerified::assertion())
-            }
-        }
-
-        let mut client_config = ClientConfig::new();
-        client_config.clone_from(self);
-        client_config.dangerous()
-            .set_certificate_verifier(Arc::new(NoCertVerifier));
-
-        Arc::new(client_config).connect_async("", stream)
-    }
 }
 
 #[inline]
diff --git a/tests/test.rs b/tests/test.rs
index ecf659d..86c715e 100644
--- a/tests/test.rs
+++ b/tests/test.rs
@@ -60,7 +60,7 @@ fn start_server(cert: Vec<Certificate>, rsa: PrivateKey) -> SocketAddr {
     recv.recv().unwrap()
 }
 
-fn start_client(addr: &SocketAddr, domain: Option<&str>, chain: Option<BufReader<Cursor<&str>>>) -> io::Result<()> {
+fn start_client(addr: &SocketAddr, domain: &str, chain: Option<BufReader<Cursor<&str>>>) -> io::Result<()> {
     let mut config = ClientConfig::new();
     if let Some(mut chain) = chain {
         config.root_store.add_pem_file(&mut chain).unwrap();
@@ -72,17 +72,7 @@ fn start_client(addr: &SocketAddr, domain: Option<&str>, chain: Option<BufReader
 
     #[allow(unreachable_code, unused_variables)]
     let done = TcpStream::connect(addr, &handle)
-        .and_then(|stream| if let Some(domain) = domain {
-            config.connect_async(domain, stream)
-        } else {
-            #[cfg(feature = "danger")]
-            let c = config.danger_connect_async_without_providing_domain_for_certificate_verification_and_server_name_indication(stream);
-
-            #[cfg(not(feature = "danger"))]
-            let c = panic!();
-
-            c
-        })
+        .and_then(|stream| config.connect_async(domain, stream))
         .and_then(|stream| aio::write_all(stream, HELLO_WORLD))
         .and_then(|(stream, _)| aio::read_exact(stream, vec![0; HELLO_WORLD.len()]))
         .and_then(|(_, buf)| {
@@ -102,10 +92,7 @@ fn main() {
 
     let addr = start_server(cert, keys.pop().unwrap());
 
-    start_client(&addr, Some("localhost"), Some(chain)).unwrap();
-
-    #[cfg(feature = "danger")]
-    start_client(&addr, None, None).unwrap();
+    start_client(&addr, "localhost", Some(chain)).unwrap();
 }
 
 #[should_panic]
@@ -117,5 +104,5 @@ fn fail() {
 
     let addr = start_server(cert, keys.pop().unwrap());
 
-    start_client(&addr, Some("google.com"), Some(chain)).unwrap();
+    start_client(&addr, "google.com", Some(chain)).unwrap();
 }