Add unwrapKey to typescript interface

js/ccf-app/src/crypto.ts

@@ -42,6 +42,11 @@ export const generateEddsaKeyPair = ccf.crypto.generateEddsaKeyPair;
  */
 export const wrapKey = ccf.crypto.wrapKey;
 
+/**
+ * @inheritDoc global!CCFCrypto.unwrapKey
+ */
+export const unwrapKey = ccf.crypto.unwrapKey;
+
 /**
  * @inheritDoc global!CCFCrypto.sign
  */

js/ccf-app/src/global.ts

@@ -387,6 +387,18 @@ export interface CCFCrypto {
     wrapAlgo: WrapAlgoParams,
   ): ArrayBuffer;
 
+  /**
+   * Unwraps a key using a wrapping key.
+   *
+   * Constraints on the `key` and `wrappingKey` parameters depend
+   * on the wrapping algorithm that is used (`wrapAlgo`).
+   */
+  unwrapKey(
+    key: ArrayBuffer,
+    wrappingKey: ArrayBuffer,
+    wrapAlgo: WrapAlgoParams,
+  ): ArrayBuffer;
+
   /**
    * Generate a digest (hash) of the given data.
    */

js/ccf-app/src/polyfill.ts

@@ -311,6 +311,58 @@ class CCFPolyfill implements CCF {
         throw new Error("unsupported wrapAlgo.name");
       }
     },
+    unwrapKey(
+      wrappedKey: ArrayBuffer,
+      unwrappingKey: ArrayBuffer,
+      unwrapAlgo: WrapAlgoParams,
+    ): ArrayBuffer {
+      if (unwrapAlgo.name == "RSA-OAEP") {
+        return nodeBufToArrBuf(
+          jscrypto.privateDecrypt(
+            {
+              key: Buffer.from(unwrappingKey),
+              oaepHash: "sha256",
+              padding: jscrypto.constants.RSA_PKCS1_OAEP_PADDING,
+            },
+            new Uint8Array(wrappedKey),
+          ),
+        );
+      } else if (unwrapAlgo.name == "AES-KWP") {
+        const iv = Buffer.from("A65959A6", "hex"); // defined in RFC 5649
+        const decipher = jscrypto.createDecipheriv(
+          "id-aes256-wrap-pad",
+          new Uint8Array(unwrappingKey),
+          iv,
+        );
+        return nodeBufToArrBuf(
+          Buffer.concat([
+            decipher.update(new Uint8Array(wrappedKey)),
+            decipher.final(),
+          ]),
+        );
+      } else if (unwrapAlgo.name == "RSA-OAEP-AES-KWP") {
+        const keyInfo = jscrypto.createPrivateKey(Buffer.from(unwrappingKey));
+        // asymmetricKeyDetails added in Node.js 15.7.0, we're at 16.
+        console.log(
+          `Modulus length: `,
+          keyInfo?.asymmetricKeyDetails?.modulusLength,
+        );
+        const modulusLengthInBytes =
+          (keyInfo?.asymmetricKeyDetails?.modulusLength || 2048) / 8;
+
+        const wrap1 = wrappedKey.slice(0, modulusLengthInBytes);
+        const wrap2 = wrappedKey.slice(modulusLengthInBytes);
+        const aesKey = this.unwrapKey(wrap1, unwrappingKey, {
+          name: "RSA-OAEP",
+          label: unwrapAlgo.label,
+        });
+        return this.unwrapKey(wrap2, aesKey, {
+          name: "AES-KWP",
+        });
+      } else {
+        throw new Error("unsupported unwrapAlgo.name");
+      }
+    },
     digest(algorithm: DigestAlgorithm, data: ArrayBuffer): ArrayBuffer {
       if (algorithm === "SHA-256") {
         return nodeBufToArrBuf(
@@ -533,6 +585,14 @@ class CCFPolyfill implements CCF {
     return this.crypto.wrapKey(key, wrappingKey, parameters);
   }
 
+  unwrapKey(
+    key: ArrayBuffer,
+    wrappingKey: ArrayBuffer,
+    parameters: WrapAlgoParams,
+  ): ArrayBuffer {
+    return this.crypto.unwrapKey(key, wrappingKey, parameters);
+  }
+
   digest(algorithm: DigestAlgorithm, data: ArrayBuffer): ArrayBuffer {
     return this.crypto.digest(algorithm, data);
   }

js/ccf-app/test/crypto.ts

@@ -1,65 +1,5 @@
 import * as crypto from "crypto";
 import forge from "node-forge";
-import { WrapAlgoParams } from "../src/global.js";
-
-function nodeBufToArrBuf(buf: Buffer): ArrayBuffer {
-  // Note: buf.buffer is not safe, see docs.
-  const arrBuf = new ArrayBuffer(buf.byteLength);
-  buf.copy(new Uint8Array(arrBuf));
-  return arrBuf;
-}
-
-export function unwrapKey(
-  wrappedKey: ArrayBuffer,
-  unwrappingKey: ArrayBuffer,
-  unwrapAlgo: WrapAlgoParams,
-): ArrayBuffer {
-  if (unwrapAlgo.name == "RSA-OAEP") {
-    return nodeBufToArrBuf(
-      crypto.privateDecrypt(
-        {
-          key: Buffer.from(unwrappingKey),
-          oaepHash: "sha256",
-          padding: crypto.constants.RSA_PKCS1_OAEP_PADDING,
-        },
-        new Uint8Array(wrappedKey),
-      ),
-    );
-  } else if (unwrapAlgo.name == "AES-KWP") {
-    const iv = Buffer.from("A65959A6", "hex"); // defined in RFC 5649
-    const decipher = crypto.createDecipheriv(
-      "id-aes256-wrap-pad",
-      new Uint8Array(unwrappingKey),
-      iv,
-    );
-    return nodeBufToArrBuf(
-      Buffer.concat([
-        decipher.update(new Uint8Array(wrappedKey)),
-        decipher.final(),
-      ]),
-    );
-  } else if (unwrapAlgo.name == "RSA-OAEP-AES-KWP") {
-    /*
-    const keyInfo = crypto.createPrivateKey(unwrappingKey);
-    // asymmetricKeyDetails added in Node.js 15.7.0, we're at 14.
-    const modulusLengthInBytes = keyInfo.asymmetricKeyDetails.modulusLength / 8;
-    */
-    // For now, hard-coded for the test in polyfill.test.ts.
-    const modulusLengthInBytes = 2048 / 8;
-
-    const wrap1 = wrappedKey.slice(0, modulusLengthInBytes);
-    const wrap2 = wrappedKey.slice(modulusLengthInBytes);
-    const aesKey = unwrapKey(wrap1, unwrappingKey, {
-      name: "RSA-OAEP",
-      label: unwrapAlgo.label,
-    });
-    return unwrapKey(wrap2, aesKey, {
-      name: "AES-KWP",
-    });
-  } else {
-    throw new Error("unsupported unwrapAlgo.name");
-  }
-}
 
 export function generateSelfSignedCert() {
   const keys = crypto.generateKeyPairSync("rsa", {

js/ccf-app/test/polyfill.test.ts

@@ -8,11 +8,7 @@ import {
   RsaOaepAesKwpParams,
   RsaOaepParams,
 } from "../src/global.js";
-import {
-  unwrapKey,
-  generateSelfSignedCert,
-  generateCertChain,
-} from "./crypto.js";
+import { generateSelfSignedCert, generateCertChain } from "./crypto.js";
 
 beforeEach(function () {
   // clear KV before each test
@@ -92,7 +88,7 @@ describe("polyfill", function () {
         ccf.strToBuf(wrappingKey.publicKey),
         wrapAlgo,
       );
-      const unwrapped = unwrapKey(
+      const unwrapped = ccf.crypto.unwrapKey(
         wrapped,
         ccf.strToBuf(wrappingKey.privateKey),
         wrapAlgo,
@@ -106,7 +102,7 @@ describe("polyfill", function () {
         name: "AES-KWP",
       };
       const wrapped = ccf.crypto.wrapKey(key, wrappingKey, wrapAlgo);
-      const unwrapped = unwrapKey(wrapped, wrappingKey, wrapAlgo);
+      const unwrapped = ccf.crypto.unwrapKey(wrapped, wrappingKey, wrapAlgo);
       assert.deepEqual(unwrapped, key);
     });
     it("performs RSA-OAEP-AES-KWP wrapping correctly", function () {
@@ -121,7 +117,7 @@ describe("polyfill", function () {
         ccf.strToBuf(wrappingKey.publicKey),
         wrapAlgo,
       );
-      const unwrapped = unwrapKey(
+      const unwrapped = ccf.crypto.unwrapKey(
         wrapped,
         ccf.strToBuf(wrappingKey.privateKey),
         wrapAlgo,

src/js/crypto.cpp

@@ -574,7 +574,7 @@ namespace ccf::js
 
     try
     {
-      auto algo_name = std::string(*wrap_algo_name_str);
+      auto algo_name = *wrap_algo_name_str;
       if (algo_name == "RSA-OAEP")
       {
         // key can in principle be arbitrary data (see note on maximum size
@@ -602,9 +602,12 @@ namespace ccf::js
       }
       else if (algo_name == "AES-KWP")
       {
-        std::vector<uint8_t> wrapped_key = crypto::ckm_aes_key_wrap_pad(
-          {wrapping_key, wrapping_key + wrapping_key_size},
-          {key, key + key_size});
+        std::vector<uint8_t> privateKey(
+          wrapping_key, wrapping_key + wrapping_key_size);
+        std::vector<uint8_t> wrapped_key =
+          crypto::ckm_aes_key_wrap_pad(privateKey, {key, key + key_size});
+
+        OPENSSL_cleanse(&privateKey, sizeof(privateKey));
 
         return JS_NewArrayBufferCopy(
           ctx, wrapped_key.data(), wrapped_key.size());
@@ -660,6 +663,139 @@ namespace ccf::js
     }
   }
 
+  static JSValue js_unwrap_key(
+    JSContext* ctx, JSValueConst, int argc, JSValueConst* argv)
+  {
+    if (argc != 3)
+      return JS_ThrowTypeError(
+        ctx, "Passed %d arguments, but expected 3", argc);
+
+    // API loosely modeled after
+    // https://developer.mozilla.org/en-US/docs/Web/API/SubtleCrypto/unwrapKey.
+
+    size_t key_size;
+    uint8_t* key = JS_GetArrayBuffer(ctx, &key_size, argv[0]);
+    if (!key)
+    {
+      return ccf::js::constants::Exception;
+    }
+
+    size_t unwrapping_key_size;
+    uint8_t* unwrapping_key =
+      JS_GetArrayBuffer(ctx, &unwrapping_key_size, argv[1]);
+    if (!unwrapping_key)
+    {
+      return ccf::js::constants::Exception;
+    }
+
+    js::Context& jsctx = *(js::Context*)JS_GetContextOpaque(ctx);
+
+    auto parameters = argv[2];
+    auto wrap_algo_name_val = jsctx(JS_GetPropertyStr(ctx, parameters, "name"));
+    JS_CHECK_EXC(wrap_algo_name_val);
+
+    auto wrap_algo_name_str = jsctx.to_str(wrap_algo_name_val);
+    if (!wrap_algo_name_str)
+    {
+      return ccf::js::constants::Exception;
+    }
+
+    try
+    {
+      auto algo_name = *wrap_algo_name_str;
+      if (algo_name == "RSA-OAEP")
+      {
+        // key can in principle be arbitrary data (see note on maximum size
+        // in rsa_key_pair.h). unwrapping_key is a private RSA key.
+
+        auto label_val = jsctx(JS_GetPropertyStr(ctx, parameters, "label"));
+        JS_CHECK_EXC(label_val);
+
+        size_t label_buf_size = 0;
+        uint8_t* label_buf = JS_GetArrayBuffer(ctx, &label_buf_size, label_val);
+
+        std::optional<std::vector<uint8_t>> label_opt = std::nullopt;
+        if (label_buf && label_buf_size > 0)
+        {
+          label_opt = {label_buf, label_buf + label_buf_size};
+        }
+
+        auto pemPrivateUnwrappingKey =
+          crypto::Pem(unwrapping_key, unwrapping_key_size);
+        auto unwrapped_key = crypto::ckm_rsa_pkcs_oaep_unwrap(
+          pemPrivateUnwrappingKey, {key, key + key_size}, label_opt);
+
+        OPENSSL_cleanse(
+          pemPrivateUnwrappingKey.data(), pemPrivateUnwrappingKey.size());
+
+        return JS_NewArrayBufferCopy(
+          ctx, unwrapped_key.data(), unwrapped_key.size());
+      }
+      else if (algo_name == "AES-KWP")
+      {
+        std::vector<uint8_t> privateKey(
+          unwrapping_key, unwrapping_key + unwrapping_key_size);
+        std::vector<uint8_t> unwrapped_key =
+          crypto::ckm_aes_key_unwrap_pad(privateKey, {key, key + key_size});
+
+        OPENSSL_cleanse(&privateKey, sizeof(privateKey));
+
+        return JS_NewArrayBufferCopy(
+          ctx, unwrapped_key.data(), unwrapped_key.size());
+      }
+      else if (algo_name == "RSA-OAEP-AES-KWP")
+      {
+        auto aes_key_size_value =
+          jsctx(JS_GetPropertyStr(ctx, parameters, "aesKeySize"));
+        JS_CHECK_EXC(aes_key_size_value);
+
+        int32_t aes_key_size = 0;
+        if (JS_ToInt32(ctx, &aes_key_size, aes_key_size_value) < 0)
+        {
+          return ccf::js::constants::Exception;
+        }
+
+        auto label_val = jsctx(JS_GetPropertyStr(ctx, parameters, "label"));
+        JS_CHECK_EXC(label_val);
+
+        size_t label_buf_size = 0;
+        uint8_t* label_buf = JS_GetArrayBuffer(ctx, &label_buf_size, label_val);
+
+        std::optional<std::vector<uint8_t>> label_opt = std::nullopt;
+        if (label_buf && label_buf_size > 0)
+        {
+          label_opt = {label_buf, label_buf + label_buf_size};
+        }
+
+        auto privPemUnwrappingKey =
+          crypto::Pem(unwrapping_key, unwrapping_key_size);
+        auto unwrapped_key = crypto::ckm_rsa_aes_key_unwrap(
+          privPemUnwrappingKey, {key, key + key_size}, label_opt);
+
+        OPENSSL_cleanse(
+          privPemUnwrappingKey.data(), privPemUnwrappingKey.size());
+
+        return JS_NewArrayBufferCopy(
+          ctx, unwrapped_key.data(), unwrapped_key.size());
+      }
+      else
+      {
+        return JS_ThrowRangeError(
+          ctx,
+          "unsupported key unwrapping algorithm, supported: RSA-OAEP, AES-KWP, "
+          "RSA-OAEP-AES-KWP");
+      }
+    }
+    catch (std::exception& ex)
+    {
+      return JS_ThrowInternalError(ctx, "Failed to unwrap key: %s", ex.what());
+    }
+    catch (...)
+    {
+      return JS_ThrowRangeError(ctx, "caught unknown exception");
+    }
+  }
+
   static JSValue js_sign(
     JSContext* ctx, JSValueConst, int argc, JSValueConst* argv)
   {

src/js/wrap.cpp

@@ -2314,6 +2314,11 @@ namespace ccf::js
         ctx, js_generate_eddsa_key_pair, "generateEddsaKeyPair", 1));
     JS_SetPropertyStr(
       ctx, crypto, "wrapKey", JS_NewCFunction(ctx, js_wrap_key, "wrapKey", 3));
+    JS_SetPropertyStr(
+      ctx,
+      crypto,
+      "unwrapKey",
+      JS_NewCFunction(ctx, js_unwrap_key, "unwrapKey", 3));
     JS_SetPropertyStr(
       ctx, crypto, "digest", JS_NewCFunction(ctx, js_digest, "digest", 2));
     JS_SetPropertyStr(