enterprise.platformKeys: Support the publicExponent parameter.

chrome/browser/extensions/api/enterprise_platform_keys/enterprise_platform_keys_api.cc

Index: chrome/browser/extensions/api/enterprise_platform_keys/enterprise_platform_keys_api.cc
diff --git a/chrome/browser/extensions/api/enterprise_platform_keys/enterprise_platform_keys_api.cc b/chrome/browser/extensions/api/enterprise_platform_keys/enterprise_platform_keys_api.cc
index cdf779cbf963192e5d3f4c13d40b7edd52a1a48a..c9278151ee50b9ebde572583f68c742f23283a16 100644
--- a/chrome/browser/extensions/api/enterprise_platform_keys/enterprise_platform_keys_api.cc
+++ b/chrome/browser/extensions/api/enterprise_platform_keys/enterprise_platform_keys_api.cc
@@ -22,9 +22,11 @@ namespace api_epki = api::enterprise_platform_keys_internal;
 // This error will occur if a token is removed and will be exposed to the
 // extension. Keep this in sync with the custom binding in Javascript.
 const char kErrorInvalidToken[] = "The token is not valid.";
-
+const char kErrorPublicExponent[] =
+    "The public exponent is empty or too large.";
 const char kErrorInvalidX509Cert[] =
     "Certificate is not a valid X.509 certificate.";
+
 const char kTokenIdUser[] = "user";
 
 // Returns whether |token_id| references a known Token.
@@ -33,6 +35,28 @@ bool ValidateToken(const std::string& token_id) {
   return token_id == kTokenIdUser;
 }
 
+// Converts a (big-endian) WebCrypto BigInteger, with or without leading zeros,
+// to unsigned long.
+// Note: This must be identical to the conversion used by WebCrypto (see
+//   /content/child/webcrypto/platform_crypto_nss.cc).
+bool BigIntegerToLong(const std::string& data, unsigned long* result) {
+  // TODO(padolph): Is it correct to say that empty data is an error, or does it
+  // mean value 0? See https://www.w3.org/Bugs/Public/show_bug.cgi?id=23655
+  if (data.size() == 0)
+    return false;

[Ryan Sleevi, 2014/06/03 19:35:29]

https://code.google.com/p/chromium/issues/detail?id=373552

+
+  *result = 0;
+  for (size_t i = 0; i < data.size(); ++i) {
+    size_t reverse_i = data.size() - i - 1;
+
+    if (reverse_i >= sizeof(unsigned long) && data[i])
+      return false;  // Too large for a long.
+
+    *result |= reinterpret_cast<const unsigned char&>(data[i]) << 8 * reverse_i;
+  }
+  return true;
+}
+
 }  // namespace
 
 EnterprisePlatformKeysInternalGenerateKeyFunction::
@@ -48,9 +72,14 @@ EnterprisePlatformKeysInternalGenerateKeyFunction::Run() {
   if (!ValidateToken(params->token_id))
     return RespondNow(Error(kErrorInvalidToken));
 
+  unsigned long public_exponent = 0;
+  if (!BigIntegerToLong(params->public_exponent, &public_exponent))
+    return RespondNow(Error(kErrorPublicExponent));
+
   chromeos::platform_keys::GenerateRSAKey(
       params->token_id,
       params->modulus_length,
+      public_exponent,
       base::Bind(
           &EnterprisePlatformKeysInternalGenerateKeyFunction::OnGeneratedKey,
           this),