[webcrypto] Restrict public exponent for RSA key generation to 3 or 65537.

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"
@@ skipping 143 matching lines @@
   static Status ErrorUnexpected();
 
   // The authentication tag length specified for AES-GCM encrypt/decrypt was
   // not 32, 64, 96, 104, 112, 120, or 128.
   static Status ErrorInvalidAesGcmTagLength();
 
   // The input data given to an AES-KW encrypt/decrypt operation was not a
   // multiple of 8 bytes, as required by RFC 3394.
   static Status ErrorInvalidAesKwDataLength();
 
-  // The "publicExponent" used to generate a key was invalid: either no bytes
-  // were specified, or the number was too large to fit into an "unsigned long"
-  // (implemention limitation), or the exponent was zero.
+  // The "publicExponent" used to generate a key was invalid or unsupported.
+  // Only values of 3 and 65537 are allowed.
   static Status ErrorGenerateKeyPublicExponent();
 
   // The modulus bytes were empty when importing an RSA public key.
   static Status ErrorImportRsaEmptyModulus();
 
   // The the modulus length was zero bits when generating an RSA public key.
   static Status ErrorGenerateRsaZeroModulus();
 
   // The exponent bytes were empty when importing an RSA public key.
   static Status ErrorImportRsaEmptyExponent();
@@ skipping 23 matching lines @@
   Type type_;
   blink::WebCryptoErrorType error_type_;
   std::string error_details_;
 };
 
 }  // namespace webcrypto
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_WEBCRYPTO_STATUS_H_