Replace NTLMv1 implementation with a functionally equivalent one.

net/ntlm/ntlm_client_fuzzer.cc

+// Copyright 2017 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 <stddef.h>
+#include <stdint.h>
+
+#include "base/test/fuzzed_data_provider.h"
+#include "net/ntlm/ntlm_client.h"
+#include "net/ntlm/ntlm_test_data.h"
+
+base::string16 ConsumeRandomLengthString16(
+    base::FuzzedDataProvider& data_provider,
+    size_t max_chars) {
+  std::string bytes = data_provider.ConsumeRandomLengthString(max_chars * 2);
+  return base::string16(reinterpret_cast<const base::char16*>(bytes.data()),
+                        bytes.size() / 2);
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  net::ntlm::NtlmClient client;
+
+  // Generate the input strings and challenge message. The strings will have a
+  // maximum length 1 character longer than the maximum that |NtlmClient| will
+  // accept to allow exploring the error cases.
+  base::FuzzedDataProvider fdp(data, size);
+  base::string16 domain =
+      ConsumeRandomLengthString16(fdp, net::ntlm::kMaxFqdnLen + 1);
+  base::string16 username =
+      ConsumeRandomLengthString16(fdp, net::ntlm::kMaxUsernameLen + 1);
+  base::string16 password =
+      ConsumeRandomLengthString16(fdp, net::ntlm::kMaxPasswordLen + 1);
+  std::string hostname =
+      fdp.ConsumeRandomLengthString(net::ntlm::kMaxFqdnLen + 1);
+  std::string challenge_msg_bytes = fdp.ConsumeRemainingBytes();
+
+  client.GenerateAuthenticateMessage(
+      domain, username, password, hostname, net::ntlm::test::kClientChallenge,
+      net::ntlm::Buffer(
+          reinterpret_cast<const uint8_t*>(challenge_msg_bytes.data()),
+          challenge_msg_bytes.size()));
+  return 0;
+}