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#![cfg_attr(feature = "dev", allow(unstable_features))]
#![cfg_attr(feature = "dev", feature(plugin))]
#![cfg_attr(feature = "dev", plugin(clippy))]
extern crate rustc_serialize;
extern crate crypto;
use rustc_serialize::{json, Encodable, Decodable};
use rustc_serialize::base64::{self, ToBase64, FromBase64};
use rustc_serialize::json::{ToJson, Json};
use crypto::sha2::{Sha256, Sha384, Sha512};
use crypto::hmac::Hmac;
use crypto::mac::Mac;
use crypto::digest::Digest;
use crypto::util::fixed_time_eq;
pub mod errors;
use errors::Error;
use std::collections::BTreeMap;
#[derive(Debug, PartialEq, Copy, Clone, RustcDecodable, RustcEncodable)]
pub enum Algorithm {
HS256,
HS384,
HS512
}
impl ToJson for Algorithm {
fn to_json(&self) -> Json {
match *self {
Algorithm::HS256 => Json::String("HS256".to_owned()),
Algorithm::HS384 => Json::String("HS384".to_owned()),
Algorithm::HS512 => Json::String("HS512".to_owned()),
}
}
}
pub trait Part {
type Encoded: AsRef<str>;
fn from_base64<B: AsRef<[u8]>>(encoded: B) -> Result<Self, Error> where Self: Sized;
fn to_base64(&self) -> Result<Self::Encoded, Error>;
}
impl<T> Part for T where T: Encodable + Decodable {
type Encoded = String;
fn to_base64(&self) -> Result<Self::Encoded, Error> {
let encoded = try!(json::encode(&self));
Ok(encoded.as_bytes().to_base64(base64::URL_SAFE))
}
fn from_base64<B: AsRef<[u8]>>(encoded: B) -> Result<T, Error> {
let decoded = try!(encoded.as_ref().from_base64());
let s = try!(String::from_utf8(decoded));
Ok(try!(json::decode(&s)))
}
}
#[derive(Debug, PartialEq, RustcDecodable)]
pub struct Header {
typ: String,
pub alg: Algorithm,
pub jku: Option<String>,
pub kid: Option<String>,
pub x5u: Option<String>,
pub x5t: Option<String>
}
impl Header {
pub fn new(algorithm: Algorithm) -> Header {
Header {
typ: "JWT".to_owned(),
alg: algorithm,
jku: None,
kid: None,
x5u: None,
x5t: None
}
}
}
impl Default for Header {
fn default() -> Header {
Header::new(Algorithm::HS256)
}
}
impl Encodable for Header {
fn encode<S: rustc_serialize::Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
self.to_json().encode(s)
}
}
impl ToJson for Header {
fn to_json(&self) -> Json {
let mut d = BTreeMap::new();
d.insert("typ".to_string(), self.typ.to_json());
d.insert("alg".to_string(), self.alg.to_json());
macro_rules! optional {
($field_name:ident) => (
if let Some(ref value) = self.$field_name {
d.insert(stringify!($field_name).to_string(), value.to_json());
}
)
}
optional!(jku);
optional!(kid);
optional!(x5u);
optional!(x5t);
Json::Object(d)
}
}
#[derive(Debug)]
pub struct TokenData<T: Part> {
pub header: Header,
pub claims: T
}
fn sign(data: &str, secret: &[u8], algorithm: Algorithm) -> String {
fn crypt<D: Digest>(digest: D, data: &str, secret: &[u8]) -> String {
let mut hmac = Hmac::new(digest, secret);
hmac.input(data.as_bytes());
hmac.result().code().to_base64(base64::URL_SAFE)
}
match algorithm {
Algorithm::HS256 => crypt(Sha256::new(), data, secret),
Algorithm::HS384 => crypt(Sha384::new(), data, secret),
Algorithm::HS512 => crypt(Sha512::new(), data, secret),
}
}
fn verify(signature: &str, data: &str, secret: &[u8], algorithm: Algorithm) -> bool {
fixed_time_eq(signature.as_ref(), sign(data, secret, algorithm).as_ref())
}
pub fn encode<T: Part>(header: Header, claims: &T, secret: &[u8]) -> Result<String, Error> {
let encoded_header = try!(header.to_base64());
let encoded_claims = try!(claims.to_base64());
let payload = [encoded_header.as_ref(), encoded_claims.as_ref()].join(".");
let signature = sign(&*payload, secret.as_ref(), header.alg);
Ok([payload, signature].join("."))
}
macro_rules! expect_two {
($iter:expr) => {{
let mut i = $iter;
match (i.next(), i.next(), i.next()) {
(Some(first), Some(second), None) => (first, second),
_ => return Err(Error::InvalidToken)
}
}}
}
pub fn decode<T: Part>(token: &str, secret: &[u8], algorithm: Algorithm) -> Result<TokenData<T>, Error> {
let (signature, payload) = expect_two!(token.rsplitn(2, '.'));
let is_valid = verify(
signature,
payload,
secret,
algorithm
);
if !is_valid {
return Err(Error::InvalidSignature);
}
let (claims, header) = expect_two!(payload.rsplitn(2, '.'));
let header = try!(Header::from_base64(header));
if header.alg != algorithm {
return Err(Error::WrongAlgorithmHeader);
}
let decoded_claims = try!(T::from_base64(claims));
Ok(TokenData { header: header, claims: decoded_claims})
}
#[cfg(test)]
mod tests {
use super::{encode, decode, Algorithm, Header, sign, verify};
#[derive(Debug, PartialEq, Clone, RustcEncodable, RustcDecodable)]
struct Claims {
sub: String,
company: String
}
#[test]
fn sign_hs256() {
let result = sign("hello world", b"secret", Algorithm::HS256);
let expected = "c0zGLzKEFWj0VxWuufTXiRMk5tlI5MbGDAYhzaxIYjo";
assert_eq!(result, expected);
}
#[test]
fn verify_hs256() {
let sig = "c0zGLzKEFWj0VxWuufTXiRMk5tlI5MbGDAYhzaxIYjo";
let valid = verify(sig, "hello world", b"secret", Algorithm::HS256);
assert!(valid);
}
#[test]
fn encode_with_custom_header() {
let my_claims = Claims {
sub: "b@b.com".to_owned(),
company: "ACME".to_owned()
};
let mut header = Header::default();
header.kid = Some("kid".to_owned());
let token = encode(header, &my_claims, "secret".as_ref()).unwrap();
let token_data = decode::<Claims>(&token, "secret".as_ref(), Algorithm::HS256).unwrap();
assert_eq!(my_claims, token_data.claims);
assert_eq!("kid", token_data.header.kid.unwrap());
}
#[test]
fn round_trip_claim() {
let my_claims = Claims {
sub: "b@b.com".to_owned(),
company: "ACME".to_owned()
};
let token = encode(Header::default(), &my_claims, "secret".as_ref()).unwrap();
let token_data = decode::<Claims>(&token, "secret".as_ref(), Algorithm::HS256).unwrap();
assert_eq!(my_claims, token_data.claims);
assert!(token_data.header.kid.is_none());
}
#[test]
#[should_panic(expected = "InvalidToken")]
fn decode_token_missing_parts() {
let token = "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9";
let claims = decode::<Claims>(token, "secret".as_ref(), Algorithm::HS256);
claims.unwrap();
}
#[test]
#[should_panic(expected = "InvalidSignature")]
fn decode_token_invalid_signature() {
let token = "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiJiQGIuY29tIiwiY29tcGFueSI6IkFDTUUifQ.wrong";
let claims = decode::<Claims>(token, "secret".as_ref(), Algorithm::HS256);
claims.unwrap();
}
#[test]
fn decode_token_with_bytes_secret() {
let token = "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwiY29tcGFueSI6Ikdvb2dvbCJ9.27QxgG96vpX4akKNpD1YdRGHE3_u2X35wR3EHA2eCrs";
let claims = decode::<Claims>(token, b"\x01\x02\x03", Algorithm::HS256);
assert!(claims.is_ok());
}
#[test]
fn decode_token_with_shuffled_header_fields() {
let token = "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJjb21wYW55IjoiMTIzNDU2Nzg5MCIsInN1YiI6IkpvaG4gRG9lIn0.SEIZ4Jg46VGhquuwPYDLY5qHF8AkQczF14aXM3a2c28";
let claims = decode::<Claims>(token, "secret".as_ref(), Algorithm::HS256);
assert!(claims.is_ok());
}
}