Expose cryptography backends via CryptoProvider

Cargo.toml

@@ -53,6 +53,8 @@ wasm-bindgen-test = "0.3.1"
 ed25519-dalek = { version = "2.1.1", features = ["pkcs8", "rand_core"] }
 rand = { version = "0.8.5", features = ["std"], default-features = false }
 rand_core = "0.6.4"
+# for the custom provider example
+botan = { version = "0.12.0", features = ["vendored"] }
 [target.'cfg(not(all(target_arch = "wasm32", not(any(target_os = "emscripten", target_os = "wasi")))))'.dev-dependencies]
 # For the custom time example
 time = "0.3"

README.md

@@ -15,7 +15,7 @@ jsonwebtoken = { version = "10", features = ["aws_lc_rs"] }
 serde = {version = "1.0", features = ["derive"] }
 ```
 
-Two crypto backends are available via features, `aws_lc_rs` and `rust_crypto`, exactly one of which must be enabled.
+Two crypto backends are available via features, `aws_lc_rs` and `rust_crypto`, at most one of which must be enabled. If you select neither feature, you need to provide your own `CryptoProvider`.
 
 The minimum required Rust version (MSRV) is specified in the `rust-version` field in this project's [Cargo.toml](Cargo.toml).
 

examples/custom_provider.rs

@@ -0,0 +1,138 @@
+use jsonwebtoken::{
+    Algorithm, AlgorithmFamily, DecodingKey, EncodingKey, Header, Validation,
+    crypto::{CryptoProvider, JwkUtils, JwtSigner, JwtVerifier},
+    decode, encode,
+    errors::{Error, ErrorKind},
+    signature::{Error as SigError, Signer, Verifier},
+};
+use serde::{Deserialize, Serialize};
+
+fn new_signer(algorithm: &Algorithm, key: &EncodingKey) -> Result<Box<dyn JwtSigner>, Error> {
+    let jwt_signer = match algorithm {
+        Algorithm::EdDSA => Box::new(EdDSASigner::new(key)?) as Box<dyn JwtSigner>,
+        _ => unimplemented!(),
+    };
+
+    Ok(jwt_signer)
+}
+
+fn new_verifier(algorithm: &Algorithm, key: &DecodingKey) -> Result<Box<dyn JwtVerifier>, Error> {
+    let jwt_verifier = match algorithm {
+        Algorithm::EdDSA => Box::new(EdDSAVerifier::new(key)?) as Box<dyn JwtVerifier>,
+        _ => unimplemented!(),
+    };
+
+    Ok(jwt_verifier)
+}
+
+struct EdDSASigner(botan::Privkey);
+
+impl EdDSASigner {
+    fn new(encoding_key: &EncodingKey) -> Result<Self, Error> {
+        if encoding_key.family() != AlgorithmFamily::Ed {
+            return Err(ErrorKind::InvalidKeyFormat.into());
+        }
+
+        Ok(Self(
+            botan::Privkey::load_der(encoding_key.inner())
+                .map_err(|_| ErrorKind::InvalidEddsaKey)?,
+        ))
+    }
+}
+
+impl Signer<Vec<u8>> for EdDSASigner {
+    fn try_sign(&self, msg: &[u8]) -> std::result::Result<Vec<u8>, SigError> {
+        let mut rng = botan::RandomNumberGenerator::new_system().map_err(SigError::from_source)?;
+        let mut signer = botan::Signer::new(&self.0, "Pure").map_err(SigError::from_source)?;
+        signer.update(msg).map_err(SigError::from_source)?;
+        signer.finish(&mut rng).map_err(SigError::from_source)
+    }
+}
+
+impl JwtSigner for EdDSASigner {
+    fn algorithm(&self) -> Algorithm {
+        Algorithm::EdDSA
+    }
+}
+
+struct EdDSAVerifier(botan::Pubkey);
+
+impl EdDSAVerifier {
+    fn new(decoding_key: &DecodingKey) -> Result<Self, Error> {
+        if decoding_key.family() != AlgorithmFamily::Ed {
+            return Err(ErrorKind::InvalidKeyFormat.into());
+        }
+
+        Ok(Self(
+            botan::Pubkey::load_ed25519(decoding_key.as_bytes())
+                .map_err(|_| ErrorKind::InvalidEddsaKey)?,
+        ))
+    }
+}
+
+impl Verifier<Vec<u8>> for EdDSAVerifier {
+    fn verify(&self, msg: &[u8], signature: &Vec<u8>) -> std::result::Result<(), SigError> {
+        let mut verifier = botan::Verifier::new(&self.0, "Pure").map_err(SigError::from_source)?;
+        verifier.update(msg).map_err(SigError::from_source)?;
+        verifier
+            .finish(signature)
+            .map_err(SigError::from_source)?
+            .then_some(())
+            .ok_or(SigError::new())
+    }
+}
+
+impl JwtVerifier for EdDSAVerifier {
+    fn algorithm(&self) -> Algorithm {
+        Algorithm::EdDSA
+    }
+}
+
+#[derive(Debug, Serialize, Deserialize, Clone, PartialEq, Eq)]
+pub struct Claims {
+    sub: String,
+    exp: u64,
+}
+
+fn main() {
+    // create and install our custom provider
+    let my_crypto_provider = CryptoProvider {
+        signer_factory: new_signer,
+        verifier_factory: new_verifier,
+        // the default impl uses dummy functions that panic, but we don't need them here
+        jwk_utils: JwkUtils::default(),
+    };
+    my_crypto_provider.install_default().unwrap();
+
+    // generate a new key
+    let (privkey, pubkey) = {
+        let key = botan::Privkey::create(
+            "Ed25519",
+            "",
+            &mut botan::RandomNumberGenerator::new_system().unwrap(),
+        )
+        .unwrap();
+        (key.pem_encode().unwrap(), key.pubkey().unwrap().pem_encode().unwrap())
+    };
+    let my_claims = Claims { sub: "me".to_owned(), exp: 10000000000 };
+
+    // our crypto provider only supports EdDSA
+    let header = Header::new(Algorithm::EdDSA);
+
+    let token =
+        match encode(&header, &my_claims, &EncodingKey::from_ed_pem(privkey.as_bytes()).unwrap()) {
+            Ok(t) => t,
+            Err(_) => panic!(), // in practice you would return an error
+        };
+
+    let claims = match decode::<Claims>(
+        token,
+        &DecodingKey::from_ed_pem(pubkey.as_bytes()).unwrap(),
+        &Validation::new(Algorithm::EdDSA),
+    ) {
+        Ok(c) => c.claims,
+        Err(_) => panic!(),
+    };
+
+    assert_eq!(my_claims, claims);
+}

src/algorithms.rs

@@ -5,10 +5,15 @@ use serde::{Deserialize, Serialize};
 use crate::errors::{Error, ErrorKind, Result};
 
 #[derive(Debug, Eq, PartialEq, Copy, Clone, Serialize, Deserialize)]
+/// Supported families of algorithms.
 pub enum AlgorithmFamily {
+    /// HMAC shared secret family.
     Hmac,
+    /// RSA-based public key family.
     Rsa,
+    /// Edwards curve public key family.
     Ec,
+    /// Elliptic curve public key family.
     Ed,
 }
 
@@ -34,6 +39,7 @@ impl AlgorithmFamily {
 /// The algorithms supported for signing/verifying JWTs
 #[allow(clippy::upper_case_acronyms)]
 #[derive(Debug, Default, PartialEq, Eq, Hash, Copy, Clone, Serialize, Deserialize)]
+#[non_exhaustive]
 pub enum Algorithm {
     /// HMAC using SHA-256
     #[default]

src/crypto/aws_lc/ecdsa.rs

@@ -18,7 +18,7 @@ macro_rules! define_ecdsa_signer {
 
         impl $name {
             pub(crate) fn new(encoding_key: &EncodingKey) -> Result<Self> {
-                if encoding_key.family != AlgorithmFamily::Ec {
+                if encoding_key.family() != AlgorithmFamily::Ec {
                     return Err(new_error(ErrorKind::InvalidKeyFormat));
                 }
 
@@ -51,7 +51,7 @@ macro_rules! define_ecdsa_verifier {
 
         impl $name {
             pub(crate) fn new(decoding_key: &DecodingKey) -> Result<Self> {
-                if decoding_key.family != AlgorithmFamily::Ec {
+                if decoding_key.family() != AlgorithmFamily::Ec {
                     return Err(new_error(ErrorKind::InvalidKeyFormat));
                 }
 

src/crypto/aws_lc/eddsa.rs

@@ -11,7 +11,7 @@ pub struct EdDSASigner(Ed25519KeyPair);
 
 impl EdDSASigner {
     pub(crate) fn new(encoding_key: &EncodingKey) -> Result<Self> {
-        if encoding_key.family != AlgorithmFamily::Ed {
+        if encoding_key.family() != AlgorithmFamily::Ed {
             return Err(new_error(ErrorKind::InvalidKeyFormat));
         }
 
@@ -38,7 +38,7 @@ pub struct EdDSAVerifier(DecodingKey);
 
 impl EdDSAVerifier {
     pub(crate) fn new(decoding_key: &DecodingKey) -> Result<Self> {
-        if decoding_key.family != AlgorithmFamily::Ed {
+        if decoding_key.family() != AlgorithmFamily::Ed {
             return Err(new_error(ErrorKind::InvalidKeyFormat));
         }
 

src/crypto/aws_lc/mod.rs

@@ -1,4 +1,61 @@
-pub(crate) mod ecdsa;
-pub(crate) mod eddsa;
-pub(crate) mod hmac;
-pub(crate) mod rsa;
+use aws_lc_rs::{
+    digest,
+    signature::{self as aws_sig, KeyPair},
+};
+
+use crate::{
+    Algorithm, DecodingKey, EncodingKey,
+    crypto::{CryptoProvider, JwkUtils, JwtSigner, JwtVerifier},
+    errors::{self, Error, ErrorKind},
+    jwk::{EllipticCurve, ThumbprintHash},
+};
+
+mod ecdsa;
+mod eddsa;
+mod hmac;
+mod rsa;
+
+fn extract_rsa_public_key_components(key_content: &[u8]) -> errors::Result<(Vec<u8>, Vec<u8>)> {
+    let key_pair = aws_sig::RsaKeyPair::from_der(key_content)
+        .map_err(|e| ErrorKind::InvalidRsaKey(e.to_string()))?;
+    let public = key_pair.public_key();
+    let components = aws_sig::RsaPublicKeyComponents::<Vec<u8>>::from(public);
+    Ok((components.n, components.e))
+}
+
+fn extract_ec_public_key_coordinates(
+    key_content: &[u8],
+    alg: Algorithm,
+) -> errors::Result<(EllipticCurve, Vec<u8>, Vec<u8>)> {
+    use aws_lc_rs::signature::{
+        ECDSA_P256_SHA256_FIXED_SIGNING, ECDSA_P384_SHA384_FIXED_SIGNING, EcdsaKeyPair,
+    };
+
+    let (signing_alg, curve, pub_elem_bytes) = match alg {
+        Algorithm::ES256 => (&ECDSA_P256_SHA256_FIXED_SIGNING, EllipticCurve::P256, 32),
+        Algorithm::ES384 => (&ECDSA_P384_SHA384_FIXED_SIGNING, EllipticCurve::P384, 48),
+        _ => return Err(ErrorKind::InvalidEcdsaKey.into()),
+    };
+
+    let key_pair = EcdsaKeyPair::from_pkcs8(signing_alg, key_content)
+        .map_err(|_| ErrorKind::InvalidEcdsaKey)?;
+
+    let pub_bytes = key_pair.public_key().as_ref();
+    if pub_bytes[0] != 4 {
+        return Err(ErrorKind::InvalidEcdsaKey.into());
+    }
+
+    let (x, y) = pub_bytes[1..].split_at(pub_elem_bytes);
+    Ok((curve, x.to_vec(), y.to_vec()))
+}
+
+fn compute_digest(data: &[u8], hash_function: ThumbprintHash) -> Vec<u8> {
+    let algorithm = match hash_function {
+        ThumbprintHash::SHA256 => &digest::SHA256,
+        ThumbprintHash::SHA384 => &digest::SHA384,
+        ThumbprintHash::SHA512 => &digest::SHA512,
+    };
+    digest::digest(algorithm, data).as_ref().to_vec()
+}
+
+define_default_provider!("aws_lc_rs", "https://github.com/aws/aws-lc-rs");

src/crypto/aws_lc/rsa.rs

@@ -37,7 +37,7 @@ fn verify_rsa(
     msg: &[u8],
     signature: &[u8],
 ) -> std::result::Result<(), signature::Error> {
-    match &decoding_key.kind {
+    match decoding_key.kind() {
         DecodingKeyKind::SecretOrDer(bytes) => {
             let public_key = crypto_sig::UnparsedPublicKey::new(algorithm, bytes);
             public_key.verify(msg, signature).map_err(signature::Error::from_source)?;
@@ -57,7 +57,7 @@ macro_rules! define_rsa_signer {
 
         impl $name {
             pub(crate) fn new(encoding_key: &EncodingKey) -> Result<Self> {
-                if encoding_key.family != AlgorithmFamily::Rsa {
+                if encoding_key.family() != AlgorithmFamily::Rsa {
                     return Err(new_error(ErrorKind::InvalidKeyFormat));
                 }
 
@@ -85,7 +85,7 @@ macro_rules! define_rsa_verifier {
 
         impl $name {
             pub(crate) fn new(decoding_key: &DecodingKey) -> Result<Self> {
-                if decoding_key.family != AlgorithmFamily::Rsa {
+                if decoding_key.family() != AlgorithmFamily::Rsa {
                     return Err(new_error(ErrorKind::InvalidKeyFormat));
                 }