fix: convert RSA private key to JWK (#4055)

fix: allow conversion RSA->JWK if only private key is given
eclipse-edc · Mar 27, 2024 · e372688 · e372688
1 parent f2ca192
commit e372688
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Showing 2 changed files with 46 additions and 2 deletions.
diff --git a/...b/crypto-common-lib/src/main/java/org/eclipse/edc/security/token/jwt/CryptoConverter.java b/...b/crypto-common-lib/src/main/java/org/eclipse/edc/security/token/jwt/CryptoConverter.java
@@ -50,6 +50,7 @@
 import java.security.interfaces.EdECKey;
 import java.security.interfaces.EdECPrivateKey;
 import java.security.interfaces.EdECPublicKey;
+import java.security.interfaces.RSAPrivateCrtKey;
 import java.security.interfaces.RSAPublicKey;
 import java.security.spec.ECGenParameterSpec;
 import java.security.spec.ECPoint;
@@ -302,8 +303,24 @@ private static Curve getCurveAllowing(EdECKey edKey, String... allowedCurves) {
     }
 
     private static RSAKey convertRsaKey(KeyPair keypair, @Nullable String kid) {
-        return new RSAKey.Builder((RSAPublicKey) keypair.getPublic())
-                .privateKey(keypair.getPrivate())
+
+        if (keypair.getPublic() == null && keypair.getPrivate() == null) {
+            throw new IllegalArgumentException("Either the public or the private key of a keypair must be non-null when converting RSA -> JWK");
+        }
+        var key = Optional.ofNullable(keypair.getPublic()).orElseGet(() -> {
+            var keySpec = new java.security.spec.RSAPublicKeySpec(((RSAPrivateCrtKey) keypair.getPrivate()).getModulus(), ((RSAPrivateCrtKey) keypair.getPrivate()).getPublicExponent());
+            try {
+                var gen = KeyFactory.getInstance("RSA");
+                return gen.generatePublic(keySpec);
+            } catch (NoSuchAlgorithmException | InvalidKeySpecException e) {
+                throw new RuntimeException(e);
+            }
+        });
+        var builder = new RSAKey.Builder((RSAPublicKey) key);
+        if (keypair.getPrivate() != null) {
+            builder.privateKey(keypair.getPrivate());
+        }
+        return builder
                 .keyID(kid)
                 .keyUse(KeyUse.SIGNATURE).build();
     }

diff --git a/...ypto-common-lib/src/test/java/org/eclipse/edc/security/token/jwt/CryptoConverterTest.java b/...ypto-common-lib/src/test/java/org/eclipse/edc/security/token/jwt/CryptoConverterTest.java
@@ -148,6 +148,33 @@ void createJwk_rsaKey() throws NoSuchAlgorithmException {
         assertThat(jwk.getKeyID()).isNull();
     }
 
+    @Test
+    void createJwk_rsaKey_onlyPrivate() throws NoSuchAlgorithmException {
+        var pk = createRsa();
+        var keypair = new KeyPair(null, pk.getPrivate());
+        var jwk = CryptoConverter.createJwk(keypair);
+        assertThat(jwk).isInstanceOf(RSAKey.class);
+        assertThat(jwk.isPrivate()).isTrue();
+        assertThat(jwk.getKeyID()).isNull();
+    }
+
+    @Test
+    void createJwk_rsaKey_whenEmptyKeypair() throws NoSuchAlgorithmException {
+        var keypair = new KeyPair(null, null);
+        assertThatThrownBy(() -> CryptoConverter.createJwk(keypair))
+                .isInstanceOf(IllegalArgumentException.class);
+    }
+
+    @Test
+    void createJwk_rsaKey_onlyPublic() throws NoSuchAlgorithmException {
+        var pk = createRsa();
+        var keypair = new KeyPair(pk.getPublic(), null);
+        var jwk = CryptoConverter.createJwk(keypair);
+        assertThat(jwk).isInstanceOf(RSAKey.class);
+        assertThat(jwk.isPrivate()).isFalse();
+        assertThat(jwk.getKeyID()).isNull();
+    }
+
     @Test
     void createJwk_rsaKey_withKeyId() throws NoSuchAlgorithmException {
         var pk = createRsa();