First working version

libs/jsonwebtoken/src/crypto.rs

@@ -0,0 +1,120 @@
+use std::sync::Arc;
+
+use base64;
+use ring::{rand, digest, hmac, signature};
+use ring::constant_time::verify_slices_are_equal;
+use untrusted;
+
+use errors::{Result, ErrorKind};
+
+
+/// The algorithms supported for signing/verifying
+#[derive(Debug, PartialEq, Copy, Clone, Serialize, Deserialize)]
+pub enum Algorithm {
+    /// HMAC using SHA-256
+    HS256,
+    /// HMAC using SHA-384
+    HS384,
+    /// HMAC using SHA-512
+    HS512,
+
+    /// RSASSA-PKCS1-v1_5 using SHA-256
+    RS256,
+    /// RSASSA-PKCS1-v1_5 using SHA-384
+    RS384,
+    /// RSASSA-PKCS1-v1_5 using SHA-512
+    RS512,
+}
+
+/// The actual HS signing + encoding
+fn sign_hmac(alg: &'static digest::Algorithm, key: &[u8], signing_input: &str) -> Result<String> {
+    let signing_key = hmac::SigningKey::new(alg, key);
+    let digest = hmac::sign(&signing_key, signing_input.as_bytes());
+
+    Ok(
+        base64::encode_config::<hmac::Signature>(&digest, base64::URL_SAFE_NO_PAD)
+    )
+}
+
+/// The actual RSA signing + encoding
+/// Taken from Ring doc https://briansmith.org/rustdoc/ring/signature/index.html
+fn sign_rsa(alg: Algorithm, key: &[u8], signing_input: &str) -> Result<String> {
+    let ring_alg = match alg {
+        Algorithm::RS256 => &signature::RSA_PKCS1_SHA256,
+        Algorithm::RS384 => &signature::RSA_PKCS1_SHA384,
+        Algorithm::RS512 => &signature::RSA_PKCS1_SHA512,
+        _ => unreachable!(),
+    };
+
+    let key_pair = Arc::new(
+        signature::RSAKeyPair::from_der(untrusted::Input::from(key))
+            .map_err(|_| ErrorKind::InvalidKey)?
+    );
+    let mut signing_state = signature::RSASigningState::new(key_pair)
+        .map_err(|_| ErrorKind::InvalidKey)?;
+    let mut signature = vec![0; signing_state.key_pair().public_modulus_len()];
+    let rng = rand::SystemRandom::new();
+    signing_state.sign(ring_alg, &rng, signing_input.as_bytes(), &mut signature)
+        .map_err(|_| ErrorKind::InvalidKey)?;
+
+    Ok(
+        base64::encode_config::<[u8]>(&signature, base64::URL_SAFE_NO_PAD)
+    )
+}
+
+/// Take the payload of a JWT, sign it using the algorithm given and return
+/// the base64 url safe encoded of the result.
+///
+/// Only use this function if you want to do something other than JWT.
+pub fn sign(signing_input: &str, key: &[u8], algorithm: Algorithm) -> Result<String> {
+    match algorithm {
+        Algorithm::HS256 => sign_hmac(&digest::SHA256, key, signing_input),
+        Algorithm::HS384 => sign_hmac(&digest::SHA384, key, signing_input),
+        Algorithm::HS512 => sign_hmac(&digest::SHA512, key, signing_input),
+
+        Algorithm::RS256 | Algorithm::RS384 | Algorithm::RS512 => sign_rsa(algorithm, key, signing_input),
+//        TODO: if PKCS1 is made prublic, remove the line above and uncomment below
+//        Algorithm::RS256 => sign_rsa(&signature::RSA_PKCS1_SHA256, key, signing_input),
+//        Algorithm::RS384 => sign_rsa(&signature::RSA_PKCS1_SHA384, key, signing_input),
+//        Algorithm::RS512 => sign_rsa(&signature::RSA_PKCS1_SHA512, key, signing_input),
+    }
+}
+
+/// See Ring RSA docs for more details
+fn verify_rsa(alg: &signature::RSAParameters, signature: &str, signing_input: &str, key: &[u8]) -> Result<bool> {
+    let signature_bytes = base64::decode_config(signature, base64::URL_SAFE_NO_PAD)?;
+    let public_key_der = untrusted::Input::from(key);
+    let message = untrusted::Input::from(signing_input.as_bytes());
+    let expected_signature = untrusted::Input::from(signature_bytes.as_slice());
+
+    let res = signature::verify(alg, public_key_der, message, expected_signature);
+
+    Ok(res.is_ok())
+}
+
+/// Compares the signature given with a re-computed signature for HMAC or using the public key
+/// for RSA.
+///
+/// Only use this function if you want to do something other than JWT.
+///
+/// `signature` is the signature part of a jwt (text after the second '.')
+///
+/// `signing_input` is base64(header) + "." + base64(claims)
+pub fn verify(signature: &str, signing_input: &str, key: &[u8], algorithm: Algorithm) -> Result<bool> {
+    match algorithm {
+        Algorithm::HS256 | Algorithm::HS384 | Algorithm::HS512 => {
+            // we just re-sign the data with the key and compare if they are equal
+            let signed = sign(signing_input, key, algorithm)?;
+            Ok(verify_slices_are_equal(signature.as_ref(), signed.as_ref()).is_ok())
+        },
+        Algorithm::RS256 => verify_rsa(&signature::RSA_PKCS1_2048_8192_SHA256, signature, signing_input, key),
+        Algorithm::RS384 => verify_rsa(&signature::RSA_PKCS1_2048_8192_SHA384, signature, signing_input, key),
+        Algorithm::RS512 => verify_rsa(&signature::RSA_PKCS1_2048_8192_SHA512, signature, signing_input, key),
+    }
+}
+
+impl Default for Algorithm {
+    fn default() -> Self {
+        Algorithm::HS256
+    }
+}