Draft: Support for GSSApi Authentication for SOCKS5

Cargo.toml

@@ -8,13 +8,15 @@ readme = "README.md"
 categories = ["asynchronous", "network-programming"]
 keywords = ["tokio", "async", "proxy", "socks", "socks5"]
 license = "MIT"
-version = "0.5.2"
+version = "0.5.3"
 authors = ["Yilin Chen <sticnarf@gmail.com>"]
 edition = "2018"
 
+
 [features]
-default = ["tokio"]
+default = ["tokio", "async-trait"]
 tor = []
+gssapi = ["async-trait"]
 
 [[example]]
 name = "chainproxy"
@@ -34,10 +36,12 @@ futures-io = { version = "0.3", optional = true }
 tokio = { version = "1.0", features = ["io-util", "net"], optional = true }
 either = "1"
 thiserror = "1.0"
+async-trait = { version = "0.1.81", optional = true}
 
 [dev-dependencies]
 futures-executor = "0.3"
 futures-util = { version = "0.3", default-features = false, features = ["io"] }
 tokio = { version = "1.0", features = ["io-util", "rt-multi-thread", "net"] }
 once_cell = "1.2.0"
+hyper = "0.14"
 smol = "2.0.0"

README.md

@@ -12,7 +12,7 @@ Asynchronous SOCKS proxy support for Rust.
 - [x] `BIND` command
 - [ ] `ASSOCIATE` command
 - [x] Username/password authentication
-- [ ] GSSAPI authentication
+- [x] GSSAPI authentication
 - [ ] Asynchronous DNS resolution
 - [X] Chain proxies ([see example](examples/chainproxy.rs))
 - [X] SOCKS4

src/error.rs

@@ -71,6 +71,9 @@ pub enum Error {
 
     #[error("Request rejected because the client program and identd report different user-ids")]
     InvalidUserIdAuthFailure,
+
+    #[error("Gssapi auth failure, code: {0}")]
+    GssapiAuthFailure(u8),
 }
 
 ///// Result type of `tokio-socks`

src/lib.rs

@@ -1,6 +1,8 @@
+#[cfg(feature = "gssapi")]
+use async_trait::async_trait;
 use std::{
     borrow::Cow,
-    fmt,
+    fmt::{self, Debug},
     io::Result as IoResult,
     net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr, SocketAddrV4, SocketAddrV6, ToSocketAddrs},
     pin::Pin,
@@ -257,19 +259,63 @@ where
 /// Authentication methods
 #[derive(Debug)]
 enum Authentication<'a> {
-    Password { username: &'a str, password: &'a str },
+    Password {
+        username: &'a str,
+        password: &'a str,
+    },
+    #[cfg(feature = "gssapi")]
+    Gssapi {
+        gssapi_authenticator: GssapiAuthenticator<'a>,
+    },
     None,
 }
 
+#[cfg(feature = "gssapi")]
+pub struct GssapiAuthenticator<'a> {
+    gssapi_authenticator: &'a dyn GssapiAuthentication,
+    renegotiate_sec_token: bool,
+}
+
+#[cfg(feature = "gssapi")]
+impl<'a> GssapiAuthenticator<'a> {
+    pub fn new(gssapi_authenticator: &'a dyn GssapiAuthentication, renegotiate_sec_token: bool) -> Self {
+        GssapiAuthenticator {
+            gssapi_authenticator,
+            renegotiate_sec_token,
+        }
+    }
+}
+
+#[cfg(feature = "gssapi")]
+impl Debug for GssapiAuthenticator<'_> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "GssapiAuthenticator")
+    }
+}
+
 impl Authentication<'_> {
     fn id(&self) -> u8 {
         match self {
             Authentication::Password { .. } => 0x02,
+            #[cfg(feature = "gssapi")]
+            Authentication::Gssapi { .. } => 0x01,
             Authentication::None => 0x00,
         }
     }
 }
 
+#[cfg(feature = "gssapi")]
+#[async_trait]
+pub trait GssapiAuthentication: Send + Sync {
+    // This method retrieves the security context token,
+    // server_challenge as None:    means return the first init_sec token
+    // server_challenge as Some(x): means return the resp for the servers challenge
+    async fn get_security_context(&self, server_challenge: Option<&[u8]>) -> std::result::Result<Vec<u8>, Error>;
+
+    // This method performs the subnegotiation step
+    async fn get_protection_level(&self) -> std::result::Result<Vec<u8>, Error>;
+}
+
 mod error;
 pub mod io;
 pub mod tcp;