mbedtls 0.13.6

Idiomatic Rust wrapper for MbedTLS, allowing you to use MbedTLS with only safe code while being able to use such great Rust features like error handling and closures. Building on MbedTLS's focus on embedded use, this crate can be used in a no_std environment.
Documentation
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/* Copyright (c) Fortanix, Inc.
 *
 * Licensed under the GNU General Public License, version 2 <LICENSE-GPL or
 * https://www.gnu.org/licenses/gpl-2.0.html> or the Apache License, Version
 * 2.0 <LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0>, at your
 * option. This file may not be copied, modified, or distributed except
 * according to those terms. */

#![cfg(not(target_env = "sgx"))]
extern crate mbedtls;

use std::future::Future;
use std::pin::Pin;
use std::sync::Arc;

use mbedtls::error::codes;
use mbedtls::pk::Pk;
use mbedtls::rng::CtrDrbg;
use mbedtls::ssl::config::{Endpoint, Preset, Transport};
use mbedtls::ssl::{Config, Context, Version};
use mbedtls::x509::{Certificate, VerifyError};
use mbedtls::Result as TlsResult;

use tokio::io::{AsyncReadExt, AsyncWriteExt};

mod support;
use support::entropy::entropy_new;
use support::keys;
use tokio::net::TcpStream;

// TODO: Add unified interface for TCP and UDP like `TransportType` in
// `client_server.rs`

async fn client(conn: TcpStream, min_version: Version, max_version: Version, exp_version: Option<Version>) -> TlsResult<()> {
    let entropy = Arc::new(entropy_new());
    let rng = Arc::new(CtrDrbg::new(entropy, None)?);
    let cacert = Arc::new(Certificate::from_pem_multiple(keys::ROOT_CA_CERT.as_bytes())?);
    let expected_flags = VerifyError::empty();
    #[cfg(feature = "time")]
    let expected_flags = expected_flags | VerifyError::CERT_EXPIRED;
    {
        let verify_callback = move |crt: &Certificate, depth: i32, verify_flags: &mut VerifyError| {
            match (crt.subject().unwrap().as_str(), depth, &verify_flags) {
                ("CN=RootCA", 1, _) => (),
                (keys::EXPIRED_CERT_SUBJECT, 0, flags) => assert_eq!(**flags, expected_flags),
                _ => assert!(false),
            };

            verify_flags.remove(VerifyError::CERT_EXPIRED); //we check the flags at the end,
                                                            //so removing this flag here prevents the connections from failing with
                                                            // VerifyError
            Ok(())
        };
        let mut config = Config::new(Endpoint::Client, Transport::Stream, Preset::Default);
        config.set_rng(rng);
        config.set_verify_callback(verify_callback);
        config.set_ca_list(cacert, None);
        config.set_min_version(min_version)?;
        config.set_max_version(max_version)?;
        let mut ctx = Context::new(Arc::new(config));

        match ctx.establish_async(conn, None).await {
            Ok(()) => {
                assert_eq!(ctx.version(), exp_version.unwrap());
            }
            Err(e) => {
                match e.high_level() {
                    Some(codes::SslBadHsProtocolVersion) => {
                        assert!(exp_version.is_none())
                    }
                    Some(codes::SslFatalAlertMessage) => {}
                    _ => panic!("Unexpected error {}", e),
                };
                return Ok(());
            }
        };

        let ciphersuite = ctx.ciphersuite().unwrap();
        ctx.write_all(format!("Client2Server {:4x}", ciphersuite).as_bytes())
            .await
            .unwrap();
        let mut buf = [0u8; 13 + 4 + 1];
        ctx.read_exact(&mut buf).await.unwrap();
        assert_eq!(&buf, format!("Server2Client {:4x}", ciphersuite).as_bytes());
    } // drop verify_callback, releasing borrow of verify_args
    Ok(())
}

async fn server(conn: TcpStream, min_version: Version, max_version: Version, exp_version: Option<Version>) -> TlsResult<()> {
    let entropy = entropy_new();
    let rng = Arc::new(CtrDrbg::new(Arc::new(entropy), None)?);
    let cert = Arc::new(Certificate::from_pem_multiple(keys::EXPIRED_CERT.as_bytes())?);
    let key = Arc::new(Pk::from_private_key(keys::EXPIRED_KEY.as_bytes(), None)?);
    let mut config = Config::new(Endpoint::Server, Transport::Stream, Preset::Default);
    config.set_rng(rng);
    config.set_min_version(min_version)?;
    config.set_max_version(max_version)?;
    config.push_cert(cert, key)?;
    let mut context = Context::new(Arc::new(config));

    match context.establish_async(conn, None).await {
        Ok(()) => {
            assert_eq!(context.version(), exp_version.unwrap());
        }
        Err(e) => {
            match (e.low_level(), e.high_level()) {
                // client just closes connection instead of sending alert
                (Some(codes::NetSendFailed), _) => {
                    assert!(exp_version.is_none())
                }
                (_, Some(codes::SslBadHsProtocolVersion)) => {}
                _ => panic!("Unexpected error {}", e),
            };
            return Ok(());
        }
    };

    //assert_eq!(ctx.get_alpn_protocol().unwrap().unwrap(), None);
    let ciphersuite = context.ciphersuite().unwrap();
    context
        .write_all(format!("Server2Client {:4x}", ciphersuite).as_bytes())
        .await
        .unwrap();
    let mut buf = [0u8; 13 + 1 + 4];
    context.read_exact(&mut buf).await.unwrap();

    assert_eq!(&buf, format!("Client2Server {:4x}", ciphersuite).as_bytes());
    Ok(())
}

async fn with_client<F, R>(conn: TcpStream, f: F) -> R
where
    F: FnOnce(Context<TcpStream>) -> Pin<Box<dyn Future<Output = R> + Send>>,
{
    let entropy = Arc::new(entropy_new());
    let rng = Arc::new(CtrDrbg::new(entropy, None).unwrap());
    let cacert = Arc::new(Certificate::from_pem_multiple(keys::ROOT_CA_CERT.as_bytes()).unwrap());

    let verify_callback = move |_crt: &Certificate, _depth: i32, verify_flags: &mut VerifyError| {
        verify_flags.remove(VerifyError::CERT_EXPIRED);
        Ok(())
    };

    let mut config = Config::new(Endpoint::Client, Transport::Stream, Preset::Default);
    config.set_rng(rng);
    config.set_verify_callback(verify_callback);
    config.set_ca_list(cacert, None);
    let mut context = Context::new(Arc::new(config));

    context.establish_async(conn, None).await.unwrap();

    f(context).await
}

async fn with_server<F, R>(conn: TcpStream, f: F) -> R
where
    F: FnOnce(Context<TcpStream>) -> Pin<Box<dyn Future<Output = R> + Send>>,
{
    let entropy = Arc::new(entropy_new());
    let rng = Arc::new(CtrDrbg::new(entropy, None).unwrap());
    let cert = Arc::new(Certificate::from_pem_multiple(keys::EXPIRED_CERT.as_bytes()).unwrap());
    let key = Arc::new(Pk::from_private_key(keys::EXPIRED_KEY.as_bytes(), None).unwrap());

    let mut config = Config::new(Endpoint::Server, Transport::Stream, Preset::Default);
    config.set_rng(rng);
    config.push_cert(cert, key).unwrap();
    let mut context = Context::new(Arc::new(config));

    context.establish_async(conn, None).await.unwrap();

    f(context).await
}

#[cfg(unix)]
mod test {
    use tokio::io::{AsyncReadExt, AsyncWriteExt};

    #[tokio::test]
    async fn async_session_client_server_test() {
        use mbedtls::ssl::Version;

        #[derive(Copy, Clone)]
        struct TestConfig {
            min_c: Version,
            max_c: Version,
            min_s: Version,
            max_s: Version,
            exp_ver: Option<Version>,
        }

        impl TestConfig {
            pub fn new(min_c: Version, max_c: Version, min_s: Version, max_s: Version, exp_ver: Option<Version>) -> Self {
                TestConfig {
                    min_c,
                    max_c,
                    min_s,
                    max_s,
                    exp_ver,
                }
            }
        }

        let test_configs = [
            TestConfig::new(
                Version::Ssl3,
                Version::Ssl3,
                Version::Ssl3,
                Version::Ssl3,
                Some(Version::Ssl3),
            ),
            TestConfig::new(
                Version::Ssl3,
                Version::Tls1_2,
                Version::Ssl3,
                Version::Ssl3,
                Some(Version::Ssl3),
            ),
            TestConfig::new(
                Version::Tls1_0,
                Version::Tls1_0,
                Version::Tls1_0,
                Version::Tls1_0,
                Some(Version::Tls1_0),
            ),
            TestConfig::new(
                Version::Tls1_1,
                Version::Tls1_1,
                Version::Tls1_1,
                Version::Tls1_1,
                Some(Version::Tls1_1),
            ),
            TestConfig::new(
                Version::Tls1_2,
                Version::Tls1_2,
                Version::Tls1_2,
                Version::Tls1_2,
                Some(Version::Tls1_2),
            ),
            TestConfig::new(
                Version::Tls1_0,
                Version::Tls1_2,
                Version::Tls1_0,
                Version::Tls1_2,
                Some(Version::Tls1_2),
            ),
            TestConfig::new(
                Version::Tls1_2,
                Version::Tls1_2,
                Version::Tls1_0,
                Version::Tls1_2,
                Some(Version::Tls1_2),
            ),
            TestConfig::new(Version::Tls1_0, Version::Tls1_1, Version::Tls1_2, Version::Tls1_2, None),
        ];

        for config in &test_configs {
            let min_c = config.min_c;
            let max_c = config.max_c;
            let min_s = config.min_s;
            let max_s = config.max_s;
            let exp_ver = config.exp_ver;

            if (max_c < Version::Tls1_2 || max_s < Version::Tls1_2) && !cfg!(feature = "legacy_protocols") {
                continue;
            }

            let (c, s) = crate::support::net::create_tcp_pair_async().unwrap();
            let c = tokio::spawn(super::client(c, min_c, max_c, exp_ver.clone()));
            let s = tokio::spawn(super::server(s, min_s, max_s, exp_ver));

            c.await.unwrap().unwrap();
            s.await.unwrap().unwrap();
        }
    }

    #[tokio::test]
    async fn async_session_shutdown1() {
        let (c, s) = crate::support::net::create_tcp_pair_async().unwrap();

        let c = tokio::spawn(super::with_client(c, |mut session| {
            Box::pin(async move {
                session.shutdown().await.unwrap();
            })
        }));

        let s = tokio::spawn(super::with_server(s, |mut session| {
            Box::pin(async move {
                let mut buf = [0u8; 1];
                match session.read(&mut buf).await {
                    Ok(0) | Err(_) => {}
                    _ => panic!("expected no data"),
                }
            })
        }));

        c.await.unwrap();
        s.await.unwrap();
    }

    #[tokio::test]
    async fn async_session_shutdown2() {
        let (c, s) = crate::support::net::create_tcp_pair_async().unwrap();

        let c = tokio::spawn(super::with_client(c, |mut session| {
            Box::pin(async move {
                let mut buf = [0u8; 5];
                session.read_exact(&mut buf).await.unwrap();
                assert_eq!(&buf, b"hello");
                match session.read(&mut buf).await {
                    Ok(0) | Err(_) => {}
                    _ => panic!("expected no data"),
                }
            })
        }));

        let s = tokio::spawn(super::with_server(s, |mut session| {
            Box::pin(async move {
                session.write_all(b"hello").await.unwrap();
                session.shutdown().await.unwrap();
            })
        }));

        c.await.unwrap();
        s.await.unwrap();
    }

    #[tokio::test]
    async fn async_session_shutdown3() {
        let (c, s) = crate::support::net::create_tcp_pair_async().unwrap();

        let c = tokio::spawn(super::with_client(c, |mut session| {
            Box::pin(async move { session.shutdown().await })
        }));

        let s = tokio::spawn(super::with_server(s, |mut session| {
            Box::pin(async move { session.shutdown().await })
        }));

        match (c.await.unwrap(), s.await.unwrap()) {
            (Err(_), Err(_)) => panic!("at least one should succeed"),
            _ => {}
        }
    }

    #[cfg(not(feature = "zlib"))]
    #[tokio::test]
    async fn write_large_buffer_ok() {
        // create a big truck of data to write&read, so that OS's Tcp buffer will be
        // full filled so that block appears during `mbedtls_ssl_write`
        let buffer_size: usize = 3 * 1024 * 1024;
        let expected_data: Vec<u8> = std::iter::repeat_with(rand::random).take(buffer_size).collect();
        let data_to_write = expected_data.clone();
        assert_eq!(expected_data, data_to_write);
        let (c, s) = crate::support::net::create_tcp_pair_async().unwrap();
        let c = tokio::spawn(super::with_client(c, move |mut session| {
            Box::pin(async move {
                session.write_all(&data_to_write).await.unwrap();
                session.shutdown().await.unwrap();
            })
        }));

        let s = tokio::spawn(super::with_server(s, move |mut session| {
            Box::pin(async move {
                let mut buf = vec![0; buffer_size];
                match session.read_exact(&mut buf).await {
                    Ok(n) => {
                        assert_eq!(n, buffer_size, "wrong length");
                        assert!(&buf[..] == &expected_data[..], "wrong read data");
                        return;
                    }
                    Err(e) => {
                        session.shutdown().await.unwrap();
                        panic!("Unexpected error {:?}", e);
                    }
                }
            })
        }));

        c.await.unwrap();
        s.await.unwrap();
    }

    /// write large buffer should ok when `poll_write` is getting an unchanging
    /// buffer when meet `Poll::Pending`
    #[cfg(not(feature = "zlib"))]
    #[tokio::test]
    async fn write_large_buffer_ok_with_unchanging_buffer() {
        // create a big truck of data to write&read, so that OS's Tcp buffer will be
        // full filled so that block appears during `mbedtls_ssl_write`
        let buffer_size: usize = 3 * 1024 * 1024;
        let expected_data: Vec<u8> = std::iter::repeat_with(rand::random).take(buffer_size).collect();
        let data_to_write = expected_data.clone();
        assert_eq!(expected_data, data_to_write);
        let (c, s) = crate::support::net::create_tcp_pair_async().unwrap();
        let c = tokio::spawn(super::with_client(c, move |mut session| {
            Box::pin(async move {
                // use a custom future for writing all buffer, which always use different length
                // when calling `poll_write`
                crate::support::custom_write_all::custom_write_all(&mut session, &data_to_write, 1)
                    .await
                    .unwrap();
                session.shutdown().await.unwrap();
            })
        }));

        let s = tokio::spawn(super::with_server(s, move |mut session| {
            Box::pin(async move {
                let mut buf = vec![0; buffer_size];
                match session.read_exact(&mut buf).await {
                    Ok(n) => {
                        assert_eq!(n, buffer_size, "wrong length");
                        assert!(&buf[..] == &expected_data[..], "wrong read data");
                        return;
                    }
                    Err(e) => {
                        session.shutdown().await.unwrap();
                        panic!("Unexpected error {:?}", e);
                    }
                }
            })
        }));

        c.await.unwrap();
        s.await.unwrap();
    }

    /// write large buffer should ok when `poll_write` is getting a increasing
    /// buffer when meet `Poll::Pending`
    #[cfg(not(feature = "zlib"))]
    #[tokio::test]
    async fn write_large_buffer_ok_with_changing_buffer_1() {
        // create a big truck of data to write&read, so that OS's Tcp buffer will be
        // full filled so that block appears during `mbedtls_ssl_write`
        let buffer_size: usize = 3 * 1024 * 1024;
        let expected_data: Vec<u8> = std::iter::repeat_with(rand::random).take(buffer_size).collect();
        let data_to_write = expected_data.clone();
        assert_eq!(expected_data, data_to_write);
        let (c, s) = crate::support::net::create_tcp_pair_async().unwrap();
        let c = tokio::spawn(super::with_client(c, move |mut session| {
            Box::pin(async move {
                // use a custom future for writing all buffer, which always use different length
                // when calling `poll_write`
                crate::support::custom_write_all::custom_write_all(&mut session, &data_to_write, 1)
                    .await
                    .unwrap();
                session.shutdown().await.unwrap();
            })
        }));

        let s = tokio::spawn(super::with_server(s, move |mut session| {
            Box::pin(async move {
                let mut buf = vec![0; buffer_size];
                match session.read_exact(&mut buf).await {
                    Ok(n) => {
                        assert_eq!(n, buffer_size, "wrong length");
                        assert!(&buf[..] == &expected_data[..], "wrong read data");
                        return;
                    }
                    Err(e) => {
                        session.shutdown().await.unwrap();
                        panic!("Unexpected error {:?}", e);
                    }
                }
            })
        }));

        c.await.unwrap();
        s.await.unwrap();
    }

    /// write large buffer should ok when `poll_write` is getting a decreasing
    /// buffer when meet `Poll::Pending`
    #[cfg(not(feature = "zlib"))]
    #[tokio::test]
    async fn write_large_buffer_ok_with_changing_buffer_2() {
        // create a big truck of data to write&read, so that OS's Tcp buffer will be
        // full filled so that block appears during `mbedtls_ssl_write`
        let buffer_size: usize = 3 * 1024 * 1024;
        let expected_data: Vec<u8> = std::iter::repeat_with(rand::random).take(buffer_size).collect();
        let data_to_write = expected_data.clone();
        assert_eq!(expected_data, data_to_write);
        let (c, s) = crate::support::net::create_tcp_pair_async().unwrap();
        let c = tokio::spawn(super::with_client(c, move |mut session| {
            Box::pin(async move {
                // use a custom future for writing all buffer, which always use different length
                // when calling `poll_write`
                crate::support::custom_write_all::custom_write_all(&mut session, &data_to_write, 1)
                    .await
                    .unwrap();
                session.shutdown().await.unwrap();
            })
        }));

        let s = tokio::spawn(super::with_server(s, move |mut session| {
            Box::pin(async move {
                let mut buf = vec![0; buffer_size];
                match session.read_exact(&mut buf).await {
                    Ok(n) => {
                        assert_eq!(n, buffer_size, "wrong length");
                        assert!(&buf[..] == &expected_data[..], "wrong read data");
                        return;
                    }
                    Err(e) => {
                        session.shutdown().await.unwrap();
                        panic!("Unexpected error {:?}", e);
                    }
                }
            })
        }));

        c.await.unwrap();
        s.await.unwrap();
    }

    /// when turn on `zlib` feature, c-mbedtls could not record buffer with
    /// size > MBEDTLS_SSL_OUT_CONTENT_LEN (default: 16 * 1024)
    /// Ref: mbedtls-sys/vendor/library/ssl_msg.c#L646-L653
    #[cfg(feature = "zlib")]
    #[tokio::test]
    async fn write_large_buffer_should_fail_with_zlib() {
        // create a big truck of data to write&read, so that OS's Tcp buffer will be
        // full filled so that block appears during `mbedtls_ssl_write`
        let buffer_size: usize = 3 * 1024 * 1024;
        let expected_data: Vec<u8> = std::iter::repeat_with(rand::random).take(buffer_size).collect();
        let data_to_write = expected_data.clone();
        assert_eq!(expected_data, data_to_write);
        let (c, s) = crate::support::net::create_tcp_pair_async().unwrap();
        let c = tokio::spawn(super::with_client(c, move |mut session| {
            Box::pin(async move {
                let ret = session.write_all(&data_to_write).await;
                assert!(ret.is_err());
                let ref err = ret.unwrap_err();
                assert_eq!(err.kind(), std::io::ErrorKind::Other);
                assert!(err.to_string().contains("SslBadInputData"));
            })
        }));

        let s = tokio::spawn(super::with_server(s, move |mut session| {
            Box::pin(async move {
                let mut buf = vec![0; buffer_size];
                match session.read_exact(&mut buf).await {
                    Ok(_) => {
                        panic!("should return error");
                    }
                    Err(e) => {
                        assert_eq!(e.kind(), std::io::ErrorKind::UnexpectedEof);
                    }
                }
            })
        }));

        c.await.unwrap();
        s.await.unwrap();
    }
}