feat: add Jwk::from_decoding_key

Allow for constructing a Jwk from a decoding key.
This allows it to be created from a DER encoded file, for example.

This patch flattens JwkUtils but adds separate structs for RSA and EC
component extraction.

Author: eyakubovich

src/crypto/aws_lc/mod.rs

@@ -8,7 +8,7 @@ use aws_lc_rs::{
 
 use crate::{
     Algorithm, DecodingKey, EncodingKey,
-    crypto::{CryptoProvider, JwkUtils, JwtSigner, JwtVerifier},
+    crypto::{CryptoProvider, JwtSigner, JwtVerifier},
     errors::{self, Error, ErrorKind},
     jwk::{EllipticCurve, ThumbprintHash},
 };
@@ -18,15 +18,23 @@ mod eddsa;
 mod hmac;
 mod rsa;
 
-fn extract_rsa_public_key_components(key_content: &[u8]) -> errors::Result<(Vec<u8>, Vec<u8>)> {
+fn rsa_components_from_private_key(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(
+fn rsa_components_from_public_key(key_content: &[u8]) -> errors::Result<(Vec<u8>, Vec<u8>)> {
+    let public = aws_lc_rs::rsa::PublicKey::from_der(key_content)
+        .map_err(|e| ErrorKind::InvalidRsaKey(e.to_string()))?;
+
+    let components = aws_sig::RsaPublicKeyComponents::<Vec<u8>>::from(&public);
+    Ok((components.n, components.e))
+}
+
+fn ec_components_from_private_key(
     key_content: &[u8],
     alg: Algorithm,
 ) -> errors::Result<(EllipticCurve, Vec<u8>, Vec<u8>)> {
@@ -102,9 +110,13 @@ fn new_verifier(
 pub static DEFAULT_PROVIDER: CryptoProvider = CryptoProvider {
     signer_factory: new_signer,
     verifier_factory: new_verifier,
-    jwk_utils: JwkUtils {
-        extract_rsa_public_key_components,
-        extract_ec_public_key_coordinates,
-        compute_digest,
+    rsa_public_components: super::RsaPublicComponents {
+        from_private_key: rsa_components_from_private_key,
+        from_public_key: rsa_components_from_public_key,
+    },
+    ec_public_components: super::EcPublicComponents {
+        from_private_key: ec_components_from_private_key,
+        from_public_key: super::ec_components_from_public_key,
     },
+    compute_digest,
 };

src/crypto/mod.rs

@@ -10,10 +10,15 @@
 //! [`CryptoProvider`]: crate::crypto::CryptoProvider
 
 use crate::algorithms::Algorithm;
-use crate::errors::Result;
+use crate::errors::{self, ErrorKind, Result};
 use crate::jwk::{EllipticCurve, ThumbprintHash};
 use crate::{DecodingKey, EncodingKey};
 
+const NOT_INSTALLED_OR_UNIMPLEMENTED_ERROR: &'static str = r###"
+Could not automatically determine the process-level CryptoProvider from jsonwebtoken crate features, or your CryptoProvider does not support JWKs.
+Call CryptoProvider::install_default() before this point to select a provider manually, or make sure exactly one of the 'rust_crypto' and 'aws_lc_rs' features is enabled.
+See the documentation of the CryptoProvider type for more information.
+"###;
 /// `aws_lc_rs` based CryptoProvider.
 #[cfg(feature = "aws_lc_rs")]
 pub mod aws_lc;
@@ -85,8 +90,13 @@ pub struct CryptoProvider {
     pub signer_factory: fn(&Algorithm, &EncodingKey) -> Result<Box<dyn JwtSigner>>,
     /// A function that produces a [`JwtVerifier`] for a given [`Algorithm`]
     pub verifier_factory: fn(&Algorithm, &DecodingKey) -> Result<Box<dyn JwtVerifier>>,
-    /// Struct with utility functions for JWK processing.
-    pub jwk_utils: JwkUtils,
+    /// Functions to extract RSA public key components from private and public keys
+    pub rsa_public_components: RsaPublicComponents,
+    /// Functions to extract EC public key components from private and public keys
+    pub ec_public_components: EcPublicComponents,
+
+    /// Given some data and a name of a hash function, compute hash_function(data)
+    pub compute_digest: fn(&[u8], ThumbprintHash) -> Vec<u8>,
 }
 
 impl CryptoProvider {
@@ -123,51 +133,81 @@ See the documentation of the CryptoProvider type for more information.
             static INSTANCE: CryptoProvider = CryptoProvider {
                 signer_factory: |_, _| panic!("{}", NOT_INSTALLED_ERROR),
                 verifier_factory: |_, _| panic!("{}", NOT_INSTALLED_ERROR),
-                jwk_utils: JwkUtils::new_unimplemented(),
+                rsa_public_components: RsaPublicComponents::new_unimplemented(),
+                ec_public_components: EcPublicComponents::new_unimplemented(),
+                compute_digest: |_, _| panic!("{}", NOT_INSTALLED_OR_UNIMPLEMENTED_ERROR),
             };
 
             &INSTANCE
         }
     }
 }
 
-/// Holds utility functions required for JWK processing.
-/// Use the [`JwkUtils::new_unimplemented`] function to initialize all values to dummies.
+/// Holds utility functions to extract RSA public key components from private and public keys
+/// Use the [`RsaPublicComponents::new_unimplemented`] function to initialize all values to dummies.
 #[derive(Clone, Debug)]
-pub struct JwkUtils {
+pub struct RsaPublicComponents {
     /// Given a DER encoded private key, extract the RSA public key components (n, e)
     #[allow(clippy::type_complexity)]
-    pub extract_rsa_public_key_components: fn(&[u8]) -> Result<(Vec<u8>, Vec<u8>)>,
+    pub from_private_key: fn(&[u8]) -> Result<(Vec<u8>, Vec<u8>)>,
+    /// Given a DER encoded public key, extract the RSA public key components (n, e)
+    #[allow(clippy::type_complexity)]
+    pub from_public_key: fn(&[u8]) -> Result<(Vec<u8>, Vec<u8>)>,
+}
+
+impl RsaPublicComponents {
+    /// Creates an instance filled with dummy functions that always panic
+    pub const fn new_unimplemented() -> Self {
+        Self {
+            from_private_key: |_| panic!("{}", NOT_INSTALLED_OR_UNIMPLEMENTED_ERROR),
+
+            from_public_key: |_| panic!("{}", NOT_INSTALLED_OR_UNIMPLEMENTED_ERROR),
+        }
+    }
+}
+
+/// Holds utility functions to extract EC public key components from private and public keys
+/// Use the [`EcPublicComponents::new_unimplemented`] function to initialize all values to dummies.
+#[derive(Clone, Debug)]
+pub struct EcPublicComponents {
     /// Given a DER encoded private key and an algorithm, extract the associated curve
     /// and the EC public key components (x, y)
     #[allow(clippy::type_complexity)]
-    pub extract_ec_public_key_coordinates:
-        fn(&[u8], Algorithm) -> Result<(EllipticCurve, Vec<u8>, Vec<u8>)>,
-    /// Given some data and a name of a hash function, compute hash_function(data)
-    pub compute_digest: fn(&[u8], ThumbprintHash) -> Vec<u8>,
+    pub from_private_key: fn(&[u8], Algorithm) -> Result<(EllipticCurve, Vec<u8>, Vec<u8>)>,
+    /// Given a DER encoded public key and an algorithm, extract the associated curve
+    /// and the EC public key components (x, y)
+    #[allow(clippy::type_complexity)]
+    pub from_public_key: fn(&[u8]) -> Result<(EllipticCurve, Vec<u8>, Vec<u8>)>,
 }
 
-impl JwkUtils {
-    /// Initialises all values to dummies.
-    /// Will lead to a panic when JWKs are required, so only use it if you don't want to support JWKs.
+impl EcPublicComponents {
+    /// Creates a instance filled with dummy functions that always panic
     pub const fn new_unimplemented() -> Self {
-        const NOT_INSTALLED_OR_UNIMPLEMENTED_ERROR: &str = r###"
-Could not automatically determine the process-level CryptoProvider from jsonwebtoken crate features, or your CryptoProvider does not support JWKs.
-Call CryptoProvider::install_default() before this point to select a provider manually, or make sure exactly one of the 'rust_crypto' and 'aws_lc_rs' features is enabled.
-See the documentation of the CryptoProvider type for more information.
-"###;
         Self {
-            extract_rsa_public_key_components: |_| {
-                panic!("{}", NOT_INSTALLED_OR_UNIMPLEMENTED_ERROR)
-            },
-            extract_ec_public_key_coordinates: |_, _| {
-                panic!("{}", NOT_INSTALLED_OR_UNIMPLEMENTED_ERROR)
-            },
-            compute_digest: |_, _| panic!("{}", NOT_INSTALLED_OR_UNIMPLEMENTED_ERROR),
+            from_private_key: |_, _| panic!("{}", NOT_INSTALLED_OR_UNIMPLEMENTED_ERROR),
+
+            from_public_key: |_| panic!("{}", NOT_INSTALLED_OR_UNIMPLEMENTED_ERROR),
         }
     }
 }
 
+pub(crate) fn ec_components_from_public_key(
+    pub_bytes: &[u8],
+) -> errors::Result<(EllipticCurve, Vec<u8>, Vec<u8>)> {
+    let (curve, pub_elem_bytes) = match pub_bytes.len() {
+        65 => (EllipticCurve::P256, 32),
+        97 => (EllipticCurve::P384, 48),
+        _ => return Err(ErrorKind::InvalidEcdsaKey.into()),
+    };
+
+    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()))
+}
+
 mod static_default {
     use std::sync::OnceLock;
 

src/crypto/rust_crypto/mod.rs

@@ -1,11 +1,15 @@
-use ::rsa::{RsaPrivateKey, pkcs1::DecodeRsaPrivateKey, traits::PublicKeyParts};
+use ::rsa::{
+    RsaPrivateKey, RsaPublicKey,
+    pkcs1::{DecodeRsaPrivateKey, DecodeRsaPublicKey},
+    traits::PublicKeyParts,
+};
 use p256::{ecdsa::SigningKey as P256SigningKey, pkcs8::DecodePrivateKey};
 use p384::ecdsa::SigningKey as P384SigningKey;
 use sha2::{Digest, Sha256, Sha384, Sha512};
 
 use crate::{
     Algorithm, DecodingKey, EncodingKey,
-    crypto::{CryptoProvider, JwkUtils, JwtSigner, JwtVerifier},
+    crypto::{CryptoProvider, JwtSigner, JwtVerifier},
     errors::{self, Error, ErrorKind},
     jwk::{EllipticCurve, ThumbprintHash},
 };
@@ -15,14 +19,20 @@ mod eddsa;
 mod hmac;
 mod rsa;
 
-fn extract_rsa_public_key_components(key_content: &[u8]) -> errors::Result<(Vec<u8>, Vec<u8>)> {
+fn rsa_components_from_private_key(key_content: &[u8]) -> errors::Result<(Vec<u8>, Vec<u8>)> {
     let private_key = RsaPrivateKey::from_pkcs1_der(key_content)
         .map_err(|e| ErrorKind::InvalidRsaKey(e.to_string()))?;
     let public_key = private_key.to_public_key();
     Ok((public_key.n().to_bytes_be(), public_key.e().to_bytes_be()))
 }
 
-fn extract_ec_public_key_coordinates(
+fn rsa_components_from_public_key(key_content: &[u8]) -> errors::Result<(Vec<u8>, Vec<u8>)> {
+    let public_key = RsaPublicKey::from_pkcs1_der(key_content)
+        .map_err(|e| ErrorKind::InvalidRsaKey(e.to_string()))?;
+    Ok((public_key.n().to_bytes_be(), public_key.e().to_bytes_be()))
+}
+
+fn ec_components_from_private_key(
     key_content: &[u8],
     alg: Algorithm,
 ) -> errors::Result<(EllipticCurve, Vec<u8>, Vec<u8>)> {
@@ -108,9 +118,13 @@ fn new_verifier(
 pub static DEFAULT_PROVIDER: CryptoProvider = CryptoProvider {
     signer_factory: new_signer,
     verifier_factory: new_verifier,
-    jwk_utils: JwkUtils {
-        extract_rsa_public_key_components,
-        extract_ec_public_key_coordinates,
-        compute_digest,
+    rsa_public_components: super::RsaPublicComponents {
+        from_private_key: rsa_components_from_private_key,
+        from_public_key: rsa_components_from_public_key,
+    },
+    ec_public_components: super::EcPublicComponents {
+        from_private_key: ec_components_from_private_key,
+        from_public_key: super::ec_components_from_public_key,
     },
+    compute_digest,
 };