Use Web Crypto for signing token requests on web

TODO figure out secure context stuff and what the broad-reaching
implications are

Resolves #1295.

TODO what can we use as the statusCode and code — used generic "bad
request"

src/common/lib/client/auth.ts

@@ -129,6 +129,7 @@ class Auth {
     if (useTokenAuth(options)) {
       /* Token auth */
       if (options.key && !hmac) {
+        // TODO what is this
         const msg = 'client-side token request signing not supported';
         Logger.logAction(Logger.LOG_ERROR, 'Auth()', msg);
         throw new Error(msg);
@@ -413,6 +414,7 @@ class Auth {
     callback: StandardCallback<API.Types.TokenDetails>
   ): void;
 
+  // TODO where is this called? it's public API but what else? _ensureValidAuthCredentials
   requestToken(
     tokenParams: API.Types.TokenParams | StandardCallback<API.Types.TokenDetails> | null,
     authOptions?: any | StandardCallback<API.Types.TokenDetails>,
@@ -559,6 +561,7 @@ class Auth {
       };
     } else if (authOptions.key) {
       Logger.logAction(Logger.LOG_MINOR, 'Auth.requestToken()', 'using token auth with client-side signing');
+      // TODO what is this?
       tokenRequestCallback = (params: any, cb: Function) => {
         this.createTokenRequest(params, authOptions, cb);
       };
@@ -745,6 +748,7 @@ class Auth {
    *
    * @param callback
    */
+  // TODO who calls this? it's public API but other than that I don't think called anywhere else except requestToken
   createTokenRequest(tokenParams: API.Types.TokenParams | null, authOptions: any, callback: Function) {
     /* shuffle and normalise arguments as necessary */
     if (typeof tokenParams == 'function' && !callback) {
@@ -829,8 +833,8 @@ class Auth {
           callback(null, request);
         })
         .catch((err) => {
-          Logger.logAction(Logger.LOG_ERROR, 'Auth.getTokenRequest()', 'failed to sign request: ' + err.message);
-          callback(ErrorInfo.fromValues(err));
+          Logger.logAction(Logger.LOG_ERROR, 'Auth.getTokenRequest()', 'failed to sign request: ' + err);
+          callback(new ErrorInfo('Failed to sign token request: ' + err.message, 40000, 400));
         });
     });
   }

src/platform/web/lib/util/crypto.ts

@@ -6,7 +6,6 @@ import ICipher from '../../../../common/types/ICipher';
 import { CryptoDataTypes } from '../../../../common/types/cryptoDataTypes';
 import BufferUtils, { Bufferlike, Output as BufferUtilsOutput } from './bufferutils';
 import { IPlatformConfig } from 'common/types/IPlatformConfig';
-import HmacSHA256 from 'crypto-js/build/hmac-sha256';
 
 // The type to which ./msgpack.ts deserializes elements of the `bin` or `ext` type
 type MessagePackBinaryType = ArrayBuffer;
@@ -212,12 +211,11 @@ var CryptoFactory = function (config: IPlatformConfig, bufferUtils: typeof Buffe
     }
 
     static async hmacSha256(message: InputPlaintext, key: API.Types.CipherKey): Promise<OutputCiphertext> {
-      const messageWordArray = bufferUtils.toWordArray(message);
-      const keyWordArray = bufferUtils.toWordArray(key);
+      // TODO what if crypto.subtle not available
+      const cryptoKey = await crypto.subtle.importKey('raw', key, { name: 'HMAC', hash: 'SHA-256' }, false, ['sign']);
+      const digest = await crypto.subtle.sign('HMAC', cryptoKey, message);
 
-      const digest = HmacSHA256(messageWordArray, keyWordArray);
-
-      return bufferUtils.toArrayBuffer(digest);
+      return digest;
     }
   }