[webcryto] Validate key usages during key creation.

content/child/webcrypto/status.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_CHILD_WEBCRYPTO_STATUS_H_
 #define CONTENT_CHILD_WEBCRYPTO_STATUS_H_
 
 #include <string>
 #include "content/common/content_export.h"
 #include "third_party/WebKit/public/platform/WebCrypto.h"
 
 namespace content {
 
 namespace webcrypto {
 
 // Status indicates whether an operation completed successfully, or with an
 // error. The error is used for verification in unit-tests, as well as for
 // display to the user.
 //
 // As such, it is important that errors DO NOT reveal any sensitive material
 // (like key bytes).
-//
-// Care must be taken with what errors are reported back to Blink when doing
-// compound operations like unwrapping a JWK key. In this case, errors
-// generated by the JWK import are not appropriate to report since the wrapped
-// JWK is not visible to the caller.
 class CONTENT_EXPORT Status {
  public:
   Status() : type_(TYPE_ERROR) {}
 
   // Returns true if the Status represents an error (any one of them).
   bool IsError() const;
 
   // Returns true if the Status represent success.
   bool IsSuccess() const;
 
@@ skipping 143 matching lines @@
   // The exponent bytes were empty when importing an RSA public key.
   static Status ErrorImportRsaEmptyExponent();
 
   // An unextractable key was used by an operation which exports the key data.
   static Status ErrorKeyNotExtractable();
 
   // The key length specified when generating a key was invalid. Either it was
   // zero, or it was not a multiple of 8 bits.
   static Status ErrorGenerateKeyLength();
 
+  // Attempted to create a key (either by importKey(), generateKey(), or
+  // unwrapKey()) however the key usages were not applicable for the key type
+  // and algorithm.
+  static Status ErrorCreateKeyBadUsages();
+
  private:
   enum Type { TYPE_ERROR, TYPE_SUCCESS };
 
   // Constructs an error with the specified error type and message.
   Status(blink::WebCryptoErrorType error_type,
          const std::string& error_details_utf8);
 
   // Constructs a success or error without any details.
   explicit Status(Type type);
 
   Type type_;
   blink::WebCryptoErrorType error_type_;
   std::string error_details_;
 };
 
 }  // namespace webcrypto
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_WEBCRYPTO_STATUS_H_