Crate sasl

This crate provides a framework for SASL authentication and a few authentication mechanisms.

Examples

Simple client-sided usage

use sasl::client::Mechanism;
use sasl::common::Credentials;
use sasl::client::mechanisms::Plain;

let creds = Credentials::default()
                        .with_username("user")
                        .with_password("pencil");

let mut mechanism = Plain::from_credentials(creds).unwrap();

let initial_data = mechanism.initial().unwrap();

assert_eq!(initial_data, b"\0user\0pencil");

More complex usage

#[macro_use] extern crate sasl;

use sasl::server::{Validator, Provider, Mechanism as ServerMechanism, Response};
use sasl::server::mechanisms::{Plain as ServerPlain, Scram as ServerScram};
use sasl::client::Mechanism as ClientMechanism;
use sasl::client::mechanisms::{Plain as ClientPlain, Scram as ClientScram};
use sasl::common::{Identity, Credentials, Password, ChannelBinding};
use sasl::common::scram::{ScramProvider, Sha1, Sha256};
use sasl::secret;

const USERNAME: &'static str = "user";
const PASSWORD: &'static str = "pencil";
const SALT: [u8; 8] = [35, 71, 92, 105, 212, 219, 114, 93];
const ITERATIONS: usize = 4096;

struct MyValidator;

impl Validator<secret::Plain> for MyValidator {
    fn validate(&self, identity: &Identity, value: &secret::Plain) -> Result<(), String> {
        let &secret::Plain(ref password) = value;
        if identity != &Identity::Username(USERNAME.to_owned()) {
            Err("authentication failed".to_owned())
        }
        else if password != PASSWORD {
            Err("authentication failed".to_owned())
        }
        else {
            Ok(())
        }
    }
}

impl Provider<secret::Pbkdf2Sha1> for MyValidator {
    fn provide(&self, identity: &Identity) -> Result<secret::Pbkdf2Sha1, String> {
        if identity != &Identity::Username(USERNAME.to_owned()) {
            Err("authentication failed".to_owned())
        }
        else {
            let digest = sasl::common::scram::Sha1::derive
                ( &Password::Plain((PASSWORD.to_owned()))
                , &SALT[..]
                , ITERATIONS )?;
            Ok(secret::Pbkdf2Sha1 {
                salt: SALT.to_vec(),
                iterations: ITERATIONS,
                digest: digest,
            })
        }
    }
}

impl_validator_using_provider!(MyValidator, secret::Pbkdf2Sha1);

impl Provider<secret::Pbkdf2Sha256> for MyValidator {
    fn provide(&self, identity: &Identity) -> Result<secret::Pbkdf2Sha256, String> {
        if identity != &Identity::Username(USERNAME.to_owned()) {
            Err("authentication failed".to_owned())
        }
        else {
            let digest = sasl::common::scram::Sha256::derive
                ( &Password::Plain((PASSWORD.to_owned()))
                , &SALT[..]
                , ITERATIONS )?;
            Ok(secret::Pbkdf2Sha256 {
                salt: SALT.to_vec(),
                iterations: ITERATIONS,
                digest: digest,
            })
        }
    }
}

impl_validator_using_provider!(MyValidator, secret::Pbkdf2Sha256);

fn finish<CM, SM>(cm: &mut CM, sm: &mut SM) -> Result<Identity, String>
    where CM: ClientMechanism,
          SM: ServerMechanism {
    let init = cm.initial()?;
    println!("C: {}", String::from_utf8_lossy(&init));
    let mut resp = sm.respond(&init)?;
    loop {
        let msg;
        match resp {
            Response::Proceed(ref data) => {
                println!("S: {}", String::from_utf8_lossy(&data));
                msg = cm.response(data)?;
                println!("C: {}", String::from_utf8_lossy(&msg));
            },
            _ => break,
        }
        resp = sm.respond(&msg)?;
    }
    if let Response::Success(ret, fin) = resp {
        println!("S: {}", String::from_utf8_lossy(&fin));
        cm.success(&fin)?;
        Ok(ret)
    }
    else {
        unreachable!();
    }
}

fn main() {
    let mut mech = ServerPlain::new(MyValidator);
    let expected_response = Response::Success(Identity::Username("user".to_owned()), Vec::new());
    assert_eq!(mech.respond(b"\0user\0pencil"), Ok(expected_response));

    let mut mech = ServerPlain::new(MyValidator);
    assert_eq!(mech.respond(b"\0user\0marker"), Err("authentication failed".to_owned()));

    let creds = Credentials::default()
                            .with_username(USERNAME)
                            .with_password(PASSWORD);
    let mut client_mech = ClientPlain::from_credentials(creds.clone()).unwrap();
    let mut server_mech = ServerPlain::new(MyValidator);

    assert_eq!(finish(&mut client_mech, &mut server_mech), Ok(Identity::Username(USERNAME.to_owned())));

    let mut client_mech = ClientScram::<Sha1>::from_credentials(creds.clone()).unwrap();
    let mut server_mech = ServerScram::<Sha1, _>::new(MyValidator, ChannelBinding::Unsupported);

    assert_eq!(finish(&mut client_mech, &mut server_mech), Ok(Identity::Username(USERNAME.to_owned())));

    let mut client_mech = ClientScram::<Sha256>::from_credentials(creds.clone()).unwrap();
    let mut server_mech = ServerScram::<Sha256, _>::new(MyValidator, ChannelBinding::Unsupported);

    assert_eq!(finish(&mut client_mech, &mut server_mech), Ok(Identity::Username(USERNAME.to_owned())));
}

Usage

You can use this in your crate by adding this under dependencies in your Cargo.toml:

sasl = "*"

Modules

client
common
secret
server

Macros

impl_validator_using_provider

Enums

Error

A wrapper enum for things that could go wrong in this crate.