[net/auth] Add fuzzer for HttpAuthHandlerBasic

The authentication scheme handler for Basic has a mini parser for
realms. Add a fuzzer so that we have some fuzz coverage here.

R=mmenke@chromium.org

Bug: None
Change-Id: Icc9501d41f31ad82d6e04f0ed9f610afbc7091aa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1907153Reviewed-by: Matt Menke <mmenke@chromium.org>
Commit-Queue: Asanka Herath <asanka@chromium.org>
Cr-Commit-Position: refs/heads/master@{#715352}

net/BUILD.gn

@@ -6665,6 +6665,18 @@ fuzzer_test("net_http_chunked_decoder_fuzzer") {
   dict = "data/fuzzer_dictionaries/http_chunked_decoder_fuzzer.dict"
 }
 
+fuzzer_test("net_http_auth_handler_basic_fuzzer") {
+  sources = [
+    "http/http_auth_handler_basic_fuzzer.cc",
+  ]
+  dict = "data/fuzzer_dictionaries/net_http_auth_handler_basic_fuzzer.dict"
+  deps = [
+    ":net_fuzzer_test_support",
+    "//net",
+    "//net/dns:test_support",
+  ]
+}
+
 fuzzer_test("net_http_content_disposition_fuzzer") {
   sources = [
     "http/http_content_disposition_fuzzer.cc",

net/data/fuzzer_dictionaries/net_http_auth_handler_basic_fuzzer.dict

+# Copyright 2019 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.
+
+"realm="
+"\""
+","
+" "
+

net/http/http_auth_handler_basic_fuzzer.cc

+// Copyright 2019 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 <memory>
+#include <string>
+
+#include "net/dns/mock_host_resolver.h"
+#include "net/http/http_auth_handler.h"
+#include "net/http/http_auth_handler_basic.h"
+#include "net/log/net_log_with_source.h"
+#include "net/ssl/ssl_info.h"
+#include "url/gurl.h"
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  std::string input(reinterpret_cast<const char*>(data), size);
+  std::string challenge = "Basic " + input;
+
+  // Dummies
+  net::SSLInfo null_ssl_info;
+  GURL origin("https://foo.test/");
+  auto host_resolver = std::make_unique<net::MockHostResolver>();
+  std::unique_ptr<net::HttpAuthHandler> basic;
+
+  net::HttpAuthHandlerBasic::Factory factory;
+  factory.CreateAuthHandlerFromString(
+      challenge, net::HttpAuth::AUTH_SERVER, null_ssl_info, origin,
+      net::NetLogWithSource(), host_resolver.get(), &basic);
+  return 0;
+}