Raw public keys support for JWT authentication (#6680)

Co-authored-by: Amaury Chamayou <[email protected]>

Author: maxtropets

CHANGELOG.md

@@ -57,6 +57,15 @@ and this project adheres Fto [Semantic Versioning](http://semver.org/spec/v2.0.0
 - All definitions in CCF's public headers are now under the `ccf::` namespace. Any application code which references any of these types directly (notably `StartupConfig`, `http_status`, `LoggerLevel`), they will now need to be prefixed with the `ccf::` namespace.
 - `cchost` now requires `--config`.
 
+### Changed
+
+- JWT authentication now supports raw public keys along with certificates (#6601).
+  - Public key information ('n' and 'e', or 'x', 'y' and 'crv' fields) now have a priority if defined in JWK set, 'x5c' remains as a backup option.
+  - Has same side-effects as #5809 does please see the changelog entry for that change for more details. In short:
+    - stale JWKs may be used for JWT validation on older nodes during the upgrade.
+    - old tables are not cleaned up, #6222 is tracking those.
+- A deprecated `GET /gov/jwt_keys/all` has been altered because of #6601, as soon as JWT certificates are no longer stored in CCF. A new "public_key" field has been added, "cert" is now left empty.
+
 ## [6.0.0-dev7]
 
 [6.0.0-dev7]: https://github.com/microsoft/CCF/releases/tag/6.0.0-dev7

doc/schemas/gov_openapi.json

@@ -799,6 +799,24 @@
         "type": "string"
       },
       "OpenIDJWKMetadata": {
+        "properties": {
+          "constraint": {
+            "$ref": "#/components/schemas/string"
+          },
+          "issuer": {
+            "$ref": "#/components/schemas/string"
+          },
+          "public_key": {
+            "$ref": "#/components/schemas/base64string"
+          }
+        },
+        "required": [
+          "issuer",
+          "public_key"
+        ],
+        "type": "object"
+      },
+      "OpenIDJWKMetadataLegacy": {
         "properties": {
           "cert": {
             "$ref": "#/components/schemas/base64string"
@@ -811,11 +829,17 @@
           }
         },
         "required": [
-          "cert",
-          "issuer"
+          "issuer",
+          "cert"
         ],
         "type": "object"
       },
+      "OpenIDJWKMetadataLegacy_array": {
+        "items": {
+          "$ref": "#/components/schemas/OpenIDJWKMetadataLegacy"
+        },
+        "type": "array"
+      },
       "OpenIDJWKMetadata_array": {
         "items": {
           "$ref": "#/components/schemas/OpenIDJWKMetadata"
@@ -1228,6 +1252,12 @@
         },
         "type": "object"
       },
+      "string_to_OpenIDJWKMetadataLegacy_array": {
+        "additionalProperties": {
+          "$ref": "#/components/schemas/OpenIDJWKMetadataLegacy_array"
+        },
+        "type": "object"
+      },
       "string_to_OpenIDJWKMetadata_array": {
         "additionalProperties": {
           "$ref": "#/components/schemas/OpenIDJWKMetadata_array"
@@ -1752,6 +1782,31 @@
       "get": {
         "deprecated": true,
         "operationId": "GetGovKvJwtPublicSigningKeysMetadata",
+        "responses": {
+          "200": {
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/string_to_OpenIDJWKMetadataLegacy_array"
+                }
+              }
+            },
+            "description": "Default response description"
+          },
+          "default": {
+            "$ref": "#/components/responses/default"
+          }
+        },
+        "summary": "This route is auto-generated from the KV schema.",
+        "x-ccf-forwarding": {
+          "$ref": "#/components/x-ccf-forwarding/sometimes"
+        }
+      }
+    },
+    "/gov/kv/jwt/public_signing_keys_metadata_v2": {
+      "get": {
+        "deprecated": true,
+        "operationId": "GetGovKvJwtPublicSigningKeysMetadataV2",
         "responses": {
           "200": {
             "content": {

include/ccf/crypto/ecdsa.h

@@ -4,6 +4,7 @@
 
 #include "ccf/crypto/curve.h"
 
+#include <span>
 #include <vector>
 
 namespace ccf::crypto
@@ -28,7 +29,7 @@ namespace ccf::crypto
    * @param signature The signature in IEEE P1363 encoding
    */
   std::vector<uint8_t> ecdsa_sig_p1363_to_der(
-    const std::vector<uint8_t>& signature);
+    std::span<const uint8_t> signature);
 
   std::vector<uint8_t> ecdsa_sig_der_to_p1363(
     const std::vector<uint8_t>& signature, CurveID curveId);

include/ccf/crypto/jwk.h

@@ -27,13 +27,12 @@ namespace ccf::crypto
     JsonWebKeyType kty;
     std::optional<std::string> kid = std::nullopt;
     std::optional<std::vector<std::string>> x5c = std::nullopt;
-    std::optional<std::string> issuer = std::nullopt;
 
     bool operator==(const JsonWebKey&) const = default;
   };
   DECLARE_JSON_TYPE_WITH_OPTIONAL_FIELDS(JsonWebKey);
   DECLARE_JSON_REQUIRED_FIELDS(JsonWebKey, kty);
-  DECLARE_JSON_OPTIONAL_FIELDS(JsonWebKey, kid, x5c, issuer);
+  DECLARE_JSON_OPTIONAL_FIELDS(JsonWebKey, kid, x5c);
 
   enum class JsonWebKeyECCurve
   {
@@ -47,6 +46,25 @@ namespace ccf::crypto
      {JsonWebKeyECCurve::P384, "P-384"},
      {JsonWebKeyECCurve::P521, "P-521"}});
 
+  struct JsonWebKeyData
+  {
+    JsonWebKeyType kty;
+    std::optional<std::string> kid = std::nullopt;
+    std::optional<std::vector<std::string>> x5c = std::nullopt;
+    std::optional<std::string> n = std::nullopt;
+    std::optional<std::string> e = std::nullopt;
+    std::optional<std::string> x = std::nullopt;
+    std::optional<std::string> y = std::nullopt;
+    std::optional<JsonWebKeyECCurve> crv = std::nullopt;
+    std::optional<std::string> issuer = std::nullopt;
+
+    bool operator==(const JsonWebKeyData&) const = default;
+  };
+  DECLARE_JSON_TYPE_WITH_OPTIONAL_FIELDS(JsonWebKeyData);
+  DECLARE_JSON_REQUIRED_FIELDS(JsonWebKeyData, kty);
+  DECLARE_JSON_OPTIONAL_FIELDS(
+    JsonWebKeyData, kid, x5c, n, e, x, y, crv, issuer);
+
   static JsonWebKeyECCurve curve_id_to_jwk_curve(CurveID curve_id)
   {
     switch (curve_id)

include/ccf/crypto/rsa_public_key.h

@@ -84,6 +84,13 @@ namespace ccf::crypto
       MDType md_type = MDType::NONE,
       size_t salt_legth = 0) = 0;
 
+    virtual bool verify_pkcs1(
+      const uint8_t* contents,
+      size_t contents_size,
+      const uint8_t* signature,
+      size_t signature_size,
+      MDType md_type = MDType::NONE) = 0;
+
     struct Components
     {
       std::vector<uint8_t> n;

include/ccf/endpoints/authentication/jwt_auth.h

@@ -17,7 +17,7 @@ namespace ccf
     nlohmann::json payload;
   };
 
-  struct VerifiersCache;
+  struct PublicKeysCache;
 
   bool validate_issuer(
     const std::string& iss,
@@ -28,7 +28,7 @@ namespace ccf
   {
   protected:
     static const OpenAPISecuritySchema security_schema;
-    std::unique_ptr<VerifiersCache> verifiers;
+    std::unique_ptr<PublicKeysCache> keys_cache;
 
   public:
     static constexpr auto SECURITY_SCHEME_NAME = "jwt";

include/ccf/service/tables/jwt.h

@@ -37,34 +37,51 @@ namespace ccf
   using JwtIssuer = std::string;
   using JwtKeyId = std::string;
   using Cert = std::vector<uint8_t>;
+  using PublicKey = std::vector<uint8_t>;
 
   struct OpenIDJWKMetadata
   {
-    Cert cert;
+    PublicKey public_key;
     JwtIssuer issuer;
     std::optional<JwtIssuer> constraint;
   };
   DECLARE_JSON_TYPE_WITH_OPTIONAL_FIELDS(OpenIDJWKMetadata);
-  DECLARE_JSON_REQUIRED_FIELDS(OpenIDJWKMetadata, cert, issuer);
+  DECLARE_JSON_REQUIRED_FIELDS(OpenIDJWKMetadata, issuer, public_key);
   DECLARE_JSON_OPTIONAL_FIELDS(OpenIDJWKMetadata, constraint);
 
-  using JwtIssuers = ServiceMap<JwtIssuer, JwtIssuerMetadata>;
-  using JwtPublicSigningKeys =
+  using JwtPublicSigningKeysMetadata =
     ServiceMap<JwtKeyId, std::vector<OpenIDJWKMetadata>>;
 
+  struct OpenIDJWKMetadataLegacy
+  {
+    Cert cert;
+    JwtIssuer issuer;
+    std::optional<JwtIssuer> constraint;
+  };
+  DECLARE_JSON_TYPE_WITH_OPTIONAL_FIELDS(OpenIDJWKMetadataLegacy);
+  DECLARE_JSON_REQUIRED_FIELDS(OpenIDJWKMetadataLegacy, issuer, cert);
+  DECLARE_JSON_OPTIONAL_FIELDS(OpenIDJWKMetadataLegacy, constraint);
+
+  using JwtPublicSigningKeysMetadataLegacy =
+    ServiceMap<JwtKeyId, std::vector<OpenIDJWKMetadataLegacy>>;
+
+  using JwtIssuers = ServiceMap<JwtIssuer, JwtIssuerMetadata>;
+
   namespace Tables
   {
     static constexpr auto JWT_ISSUERS = "public:ccf.gov.jwt.issuers";
 
     static constexpr auto JWT_PUBLIC_SIGNING_KEYS_METADATA =
-      "public:ccf.gov.jwt.public_signing_keys_metadata";
+      "public:ccf.gov.jwt.public_signing_keys_metadata_v2";
 
     namespace Legacy
     {
       static constexpr auto JWT_PUBLIC_SIGNING_KEYS =
         "public:ccf.gov.jwt.public_signing_key";
       static constexpr auto JWT_PUBLIC_SIGNING_KEY_ISSUER =
         "public:ccf.gov.jwt.public_signing_key_issuer";
+      static constexpr auto JWT_PUBLIC_SIGNING_KEYS_METADATA =
+        "public:ccf.gov.jwt.public_signing_keys_metadata";
 
       using JwtPublicSigningKeys =
         ccf::kv::RawCopySerialisedMap<JwtKeyId, Cert>;
@@ -75,7 +92,7 @@ namespace ccf
 
   struct JsonWebKeySet
   {
-    std::vector<ccf::crypto::JsonWebKey> keys;
+    std::vector<ccf::crypto::JsonWebKeyData> keys;
 
     bool operator!=(const JsonWebKeySet& rhs) const
     {

samples/constitutions/default/actions.js

@@ -130,15 +130,28 @@ function checkJwks(value, field) {
   for (const [i, jwk] of value.keys.entries()) {
     checkType(jwk.kid, "string", `${field}.keys[${i}].kid`);
     checkType(jwk.kty, "string", `${field}.keys[${i}].kty`);
-    checkType(jwk.x5c, "array", `${field}.keys[${i}].x5c`);
-    checkLength(jwk.x5c, 1, null, `${field}.keys[${i}].x5c`);
-    for (const [j, b64der] of jwk.x5c.entries()) {
-      checkType(b64der, "string", `${field}.keys[${i}].x5c[${j}]`);
-      const pem =
-        "-----BEGIN CERTIFICATE-----\n" +
-        b64der +
-        "\n-----END CERTIFICATE-----";
-      checkX509CertBundle(pem, `${field}.keys[${i}].x5c[${j}]`);
+    if (jwk.x5c) {
+      checkType(jwk.x5c, "array", `${field}.keys[${i}].x5c`);
+      checkLength(jwk.x5c, 1, null, `${field}.keys[${i}].x5c`);
+      for (const [j, b64der] of jwk.x5c.entries()) {
+        checkType(b64der, "string", `${field}.keys[${i}].x5c[${j}]`);
+        const pem =
+          "-----BEGIN CERTIFICATE-----\n" +
+          b64der +
+          "\n-----END CERTIFICATE-----";
+        checkX509CertBundle(pem, `${field}.keys[${i}].x5c[${j}]`);
+      }
+    } else if (jwk.n && jwk.e) {
+      checkType(jwk.n, "string", `${field}.keys[${i}].n`);
+      checkType(jwk.e, "string", `${field}.keys[${i}].e`);
+    } else if (jwk.x && jwk.y) {
+      checkType(jwk.x, "string", `${field}.keys[${i}].x`);
+      checkType(jwk.y, "string", `${field}.keys[${i}].y`);
+      checkType(jwk.crv, "string", `${field}.keys[${i}].crv`);
+    } else {
+      throw new Error(
+        "JWK must contain either x5c, or n/e for RSA key type, or x/y/crv for EC key type",
+      );
     }
   }
 }

src/crypto/ecdsa.cpp

@@ -45,7 +45,7 @@ namespace ccf::crypto
   }
 
   std::vector<uint8_t> ecdsa_sig_p1363_to_der(
-    const std::vector<uint8_t>& signature)
+    std::span<const uint8_t> signature)
   {
     auto half_size = signature.size() / 2;
     return ecdsa_sig_from_r_s(

src/crypto/openssl/rsa_public_key.cpp

@@ -54,6 +54,17 @@ namespace ccf::crypto
       auto msg = OpenSSL::error_string(ec);
       throw std::runtime_error(fmt::format("OpenSSL error: {}", msg));
     }
+
+// As it's a common pattern to rely on successful key wrapper construction as a
+// confirmation of a concrete key type, this must fail for non-RSA keys.
+#if defined(OPENSSL_VERSION_MAJOR) && OPENSSL_VERSION_MAJOR >= 3
+    if (!key || EVP_PKEY_get_base_id(key) != EVP_PKEY_RSA)
+#else
+    if (!key || !EVP_PKEY_get0_RSA(key))
+#endif
+    {
+      throw std::logic_error("invalid RSA key");
+    }
   }
 
   std::pair<Unique_BIGNUM, Unique_BIGNUM> get_modulus_and_exponent(
@@ -208,6 +219,22 @@ namespace ccf::crypto
              pctx, signature, signature_size, hash.data(), hash.size()) == 1;
   }
 
+  bool RSAPublicKey_OpenSSL::verify_pkcs1(
+    const uint8_t* contents,
+    size_t contents_size,
+    const uint8_t* signature,
+    size_t signature_size,
+    MDType md_type)
+  {
+    auto hash = OpenSSLHashProvider().Hash(contents, contents_size, md_type);
+    Unique_EVP_PKEY_CTX pctx(key);
+    CHECK1(EVP_PKEY_verify_init(pctx));
+    CHECK1(EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PADDING));
+    CHECK1(EVP_PKEY_CTX_set_signature_md(pctx, get_md_type(md_type)));
+    return EVP_PKEY_verify(
+             pctx, signature, signature_size, hash.data(), hash.size()) == 1;
+  }
+
   std::vector<uint8_t> RSAPublicKey_OpenSSL::bn_bytes(const BIGNUM* bn)
   {
     std::vector<uint8_t> r(BN_num_bytes(bn));