Implement decode_rsa, verify_rsa for using public key components instead of DER key.

README.md

@@ -119,7 +119,8 @@ This library currently supports the following:
 - ES384
 
 ### RSA
-`jsonwebtoken` can only read DER encoded keys currently. If you have openssl installed,
+
+Use the `decode_rsa` function to use a `(n, e)` modulus, exponent pair. Otherwise if you have openssl installed,
 you can run the following commands to obtain the DER keys from PKCS#1 (ie with `BEGIN RSA PUBLIC KEY`) .pem.
 If you have a PKCS#8 pem file (ie starting with `BEGIN PUBLIC KEY`), you will need to first convert it to PKCS#1:
 `openssl rsa -pubin -in <filename> -RSAPublicKey_out -out <filename>`.

src/crypto.rs

@@ -123,6 +123,40 @@ fn verify_ring(
     Ok(res.is_ok())
 }
 
+/// Compares the signature given with a re-computed signature using the public key for RSA.
+///
+/// `signature` is the signature part of a jwt (text after the second '.')
+///
+/// `signing_input` is base64(header) + "." + base64(claims)
+pub fn verify_rsa(
+    signature: &str,
+    signing_input: &str,
+    (n, e): (&[u8], &[u8]),
+    algorithm: Algorithm,
+) -> Result<bool> {
+    let rsa_parameters = match algorithm {
+        Algorithm::RS256 => &signature::RSA_PKCS1_2048_8192_SHA256,
+        Algorithm::RS384 => &signature::RSA_PKCS1_2048_8192_SHA384,
+        Algorithm::RS512 => &signature::RSA_PKCS1_2048_8192_SHA512,
+        _ => return Err(new_error(ErrorKind::InvalidAlgorithmName)),
+    };
+
+    let signature_bytes = base64::decode_config(signature, base64::URL_SAFE_NO_PAD)?;
+    let message = untrusted::Input::from(signing_input.as_bytes());
+    let modulus = untrusted::Input::from(n);
+    let exponent = untrusted::Input::from(e);
+    let expected_signature = untrusted::Input::from(signature_bytes.as_slice());
+
+    let res = signature::primitive::verify_rsa(
+        rsa_parameters,
+        (modulus, exponent),
+        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.
 ///

src/lib.rs

@@ -20,7 +20,7 @@ mod header;
 mod serialization;
 mod validation;
 
-pub use crypto::{sign, verify, Algorithm};
+pub use crypto::{sign, verify, verify_rsa, Algorithm};
 pub use header::Header;
 pub use serialization::TokenData;
 pub use validation::Validation;
@@ -117,6 +117,49 @@ pub fn decode<T: DeserializeOwned>(
     Ok(TokenData { header, claims: decoded_claims })
 }
 
+
+/// Decode a token into a struct containing 2 fields: `claims` and `header`.
+///
+/// If the token or its signature is invalid or the claims fail validation, it will return an error.
+///
+/// ```rust,ignore
+/// #[macro_use]
+/// extern crate serde_derive;
+/// use jsonwebtoken::{decode, Validation, Algorithm};
+///
+/// #[derive(Debug, Serialize, Deserialize)]
+/// struct Claims {
+///    sub: String,
+///    company: String
+/// }
+///
+/// let token = "a.jwt.token".to_string();
+/// // Claims is a struct that implements Deserialize
+/// let token_data = decode::<Claims>(&token, (n, e), &Validation::new(Algorithm::HS256));
+/// ```
+pub fn decode_rsa<T: DeserializeOwned>(
+    token: &str,
+    (n, e): (&[u8], &[u8]),
+    validation: &Validation,
+) -> Result<TokenData<T>> {
+    let (signature, signing_input) = expect_two!(token.rsplitn(2, '.'));
+    let (claims, header) = expect_two!(signing_input.rsplitn(2, '.'));
+    let header: Header = from_jwt_part(header)?;
+
+    if !verify_rsa(signature, signing_input, (n, e), header.alg)? {
+        return Err(new_error(ErrorKind::InvalidSignature));
+    }
+
+    if !validation.algorithms.contains(&header.alg) {
+        return Err(new_error(ErrorKind::InvalidAlgorithm));
+    }
+
+    let (decoded_claims, claims_map): (T, _) = from_jwt_part_claims(claims)?;
+    validate(&claims_map, validation)?;
+
+    Ok(TokenData { header, claims: decoded_claims })
+}
+
 /// Decode a token without any signature validation into a struct containing 2 fields: `claims` and `header`.
 ///
 /// NOTE: Do not use this unless you know what you are doing! If the token's signature is invalid, it will *not* return an error.

tests/rsa.rs

@@ -4,7 +4,7 @@ extern crate serde_derive;
 extern crate chrono;
 
 use chrono::Utc;
-use jsonwebtoken::{decode, encode, sign, verify, Algorithm, Header, Validation};
+use jsonwebtoken::{decode, encode, sign, verify, verify_rsa, Algorithm, Header, Validation};
 
 #[derive(Debug, PartialEq, Clone, Serialize, Deserialize)]
 struct Claims {
@@ -42,3 +42,35 @@ fn round_trip_claim() {
     assert_eq!(my_claims, token_data.claims);
     assert!(token_data.header.kid.is_none());
 }
+
+#[test]
+fn round_trip_verification_rsa() {
+    let modulus: Vec<u8> = vec![
+        0xc9, 0x11, 0x3a, 0xac, 0x7b, 0x8d, 0x47, 0x44, 0x1b, 0x1c, 0xed, 0xc7, 0xdc, 0xab, 0x76,
+        0xa4, 0xe2, 0x86, 0x56, 0x14, 0x2a, 0x19, 0x95, 0xc8, 0x9c, 0xe7, 0x6e, 0x40, 0xdc, 0x57,
+        0xce, 0xe2, 0xa5, 0xbd, 0x04, 0xcb, 0x51, 0x3b, 0xf8, 0x97, 0x8b, 0x20, 0x82, 0x1e, 0x7f,
+        0x09, 0x86, 0x22, 0xfd, 0xcb, 0xc8, 0xf9, 0x25, 0xd5, 0x4f, 0xd9, 0x0f, 0x59, 0x22, 0x97,
+        0xc4, 0x95, 0xc1, 0x5d, 0xdf, 0xf8, 0x2e, 0x4b, 0xdc, 0x3e, 0xe5, 0x1a, 0x90, 0x1a, 0x00,
+        0x91, 0xf8, 0x7e, 0x7a, 0x21, 0x55, 0x32, 0x1d, 0x95, 0xad, 0x4c, 0x96, 0xca, 0x3d, 0xcc,
+        0x16, 0x5d, 0x07, 0x4d, 0x51, 0x7d, 0x2b, 0x04, 0x57, 0x2c, 0x07, 0x30, 0x91, 0x11, 0x22,
+        0x4b, 0x79, 0xe9, 0x4e, 0x11, 0xd1, 0xc8, 0x8c, 0x6e, 0xcb, 0x46, 0x4c, 0x79, 0x97, 0xf1,
+        0x54, 0xbe, 0x5a, 0xac, 0xc8, 0x70, 0xd5, 0x24, 0x44, 0x2c, 0x1f, 0x07, 0xa0, 0x67, 0xc6,
+        0xfc, 0x0b, 0x47, 0xf3, 0xd0, 0x48, 0x13, 0xd8, 0xc3, 0x04, 0x76, 0x7d, 0x74, 0xb7, 0xa5,
+        0x2b, 0xd6, 0xb5, 0xf3, 0x8c, 0xc0, 0x7f, 0xc2, 0xf0, 0xa0, 0xf2, 0xf1, 0xbc, 0x96, 0xf7,
+        0x22, 0x5e, 0x67, 0x9d, 0xca, 0x8f, 0x71, 0x27, 0xca, 0x0c, 0x3a, 0x1d, 0x30, 0x50, 0x48,
+        0x31, 0xce, 0x25, 0x43, 0x30, 0xca, 0x2f, 0x98, 0x2f, 0x9a, 0x25, 0xcb, 0x5c, 0x1d, 0x40,
+        0x18, 0xb9, 0xbc, 0x28, 0x18, 0xdf, 0x13, 0xcb, 0x37, 0x2f, 0x9c, 0x6a, 0x8b, 0xec, 0x94,
+        0xa1, 0xdf, 0xa3, 0xf0, 0xcb, 0x6f, 0x22, 0x3f, 0x35, 0xd9, 0xd9, 0x12, 0xe1, 0x03, 0x22,
+        0x45, 0x53, 0x7f, 0x6f, 0x2d, 0xa1, 0xdd, 0x96, 0x3c, 0x2d, 0x85, 0x46, 0xae, 0xa6, 0x57,
+        0x65, 0x37, 0x20, 0x9f, 0x6b, 0xa3, 0x9f, 0xcb, 0x8a, 0x8d, 0x72, 0xd9, 0x54, 0x3e, 0x53,
+        0x75,
+    ];
+
+    let exponent: Vec<u8> = vec![0x01, 0x00, 0x01];
+
+    let encrypted =
+        sign("hello world", include_bytes!("private_rsa_key.der"), Algorithm::RS256).unwrap();
+    let is_valid =
+        verify_rsa(&encrypted, "hello world", (&modulus, &exponent), Algorithm::RS256).unwrap();
+    assert!(is_valid);
+}