HexStringToUInt64 should fail for negative input

base/strings/string_number_conversions.cc

 // Copyright (c) 2012 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.
 
 #include "base/strings/string_number_conversions.h"
 
 #include <ctype.h>
 #include <errno.h>
 #include <stdlib.h>
 #include <wctype.h>
@@ skipping 168 matching lines @@
                      const_iterator end,
                      value_type* output) {
     bool valid = true;
 
     while (begin != end && LocalIsWhitespace(*begin)) {
       valid = false;
       ++begin;
     }
 
     if (begin != end && *begin == '-') {
-      if (!Negative::Invoke(begin + 1, end, output)) {
+      if (!std::numeric_limits<value_type>::is_signed) {
+        valid = false;
+      } else if (!Negative::Invoke(begin + 1, end, output)) {
         valid = false;
       }
     } else {
       if (begin != end && *begin == '+') {
         ++begin;
       }
       if (!Positive::Invoke(begin, end, output)) {
         valid = false;
       }
     }
@@ skipping 302 matching lines @@
 bool HexStringToUInt64(const StringPiece& input, uint64* output) {
   return IteratorRangeToNumber<HexIteratorRangeToUInt64Traits>::Invoke(
       input.begin(), input.end(), output);
 }
 
 bool HexStringToBytes(const std::string& input, std::vector<uint8>* output) {
   return HexStringToBytesT(input, output);
 }
 
 }  // namespace base