Fix extension content verification out-of-band hash fetching

extensions/browser/content_hash_fetcher_unittest.cc

Index: extensions/browser/content_hash_fetcher_unittest.cc
diff --git a/extensions/browser/content_hash_fetcher_unittest.cc b/extensions/browser/content_hash_fetcher_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..1893309f2d93903daa8d2c4db554c8fe1b59dcae
--- /dev/null
+++ b/extensions/browser/content_hash_fetcher_unittest.cc
@@ -0,0 +1,260 @@
+// Copyright 2016 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 "base/callback.h"
+#include "base/callback_helpers.h"
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/files/scoped_temp_dir.h"
+#include "base/memory/ptr_util.h"
+#include "base/memory/weak_ptr.h"
+#include "base/path_service.h"
+#include "base/run_loop.h"
+#include "base/strings/stringprintf.h"
+#include "base/version.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/test/test_browser_thread_bundle.h"
+#include "extensions/browser/content_hash_fetcher.h"
+#include "extensions/browser/content_verifier_delegate.h"
+#include "extensions/browser/extensions_test.h"
+#include "extensions/common/constants.h"
+#include "extensions/common/extension_paths.h"
+#include "extensions/common/file_util.h"
+#include "net/url_request/test_url_request_interceptor.h"
+#include "net/url_request/url_request_interceptor.h"
+#include "net/url_request/url_request_test_util.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/zlib/google/zip.h"
+
+namespace extensions {
+
+// Used to hold the result of a callback from the ContentHashFetcher.
+struct ContentHashFetcherResult {
+  std::string extension_id;
+  bool success;
+  bool force;
+  std::set<base::FilePath> mismatch_paths;
+};
+
+// Allows waiting for the callback from a ContentHashFetcher, returning the
+// data that was passed to that callback.
+class ContentHashFetcherWaiter {
+ public:
+  ContentHashFetcherWaiter() : weak_factory_(this) {}
+
+  ContentHashFetcher::FetchCallback GetCallback() {
+    return base::Bind(&ContentHashFetcherWaiter::Callback,
+                      weak_factory_.GetWeakPtr());
+  }
+
+  std::unique_ptr<ContentHashFetcherResult> WaitForCallback() {
+    if (!result_) {
+      base::RunLoop run_loop;
+      run_loop_quit_ = run_loop.QuitClosure();
+      run_loop.Run();
+    }
+    return std::move(result_);
+  }
+
+ private:
+  // Matches signature of ContentHashFetcher::FetchCallback.
+  void Callback(const std::string& extension_id,
+                bool success,
+                bool force,
+                const std::set<base::FilePath>& mismatch_paths) {
+    result_ = base::MakeUnique<ContentHashFetcherResult>();
+    result_->extension_id = extension_id;
+    result_->success = success;
+    result_->force = force;
+    result_->mismatch_paths = mismatch_paths;
+    if (run_loop_quit_)
+      base::ResetAndReturn(&run_loop_quit_).Run();
+  }
+
+  base::Closure run_loop_quit_;
+  std::unique_ptr<ContentHashFetcherResult> result_;
+  base::WeakPtrFactory<ContentHashFetcherWaiter> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(ContentHashFetcherWaiter);
+};
+
+// Used in setting up the behavior of our ContentHashFetcher.
+class MockDelegate : public ContentVerifierDelegate {
+ public:
+  ContentVerifierDelegate::Mode ShouldBeVerified(
+      const Extension& extension) override {
+    return ContentVerifierDelegate::ENFORCE_STRICT;
+  }
+
+  ContentVerifierKey GetPublicKey() override {
+    return ContentVerifierKey(kWebstoreSignaturesPublicKey,
+                              kWebstoreSignaturesPublicKeySize);
+  }
+
+  GURL GetSignatureFetchUrl(const std::string& extension_id,
+                            const base::Version& version) override {
+    std::string url =
+        base::StringPrintf("http://localhost/getsignature?id=%s&version=%s",
+                           extension_id.c_str(), version.GetString().c_str());
+    return GURL(url);
+  }
+
+  std::set<base::FilePath> GetBrowserImagePaths(
+      const extensions::Extension* extension) override {
+    ADD_FAILURE() << "Unexpected call for this test";
+    return std::set<base::FilePath>();
+  }
+
+  void VerifyFailed(const std::string& extension_id,
+                    ContentVerifyJob::FailureReason reason) override {
+    ADD_FAILURE() << "Unexpected call for this test";
+  }
+};
+
+class ContentHashFetcherTest : public ExtensionsTest {
+ public:
+  ContentHashFetcherTest() {}
+  ~ContentHashFetcherTest() override {}
+
+  void SetUp() override {
+    ExtensionsTest::SetUp();
+    // We need a real IO thread to be able to intercept the network request
+    // for the missing verified_contents.json file.
+    browser_threads_.reset(new content::TestBrowserThreadBundle(
+        content::TestBrowserThreadBundle::REAL_IO_THREAD));
+    request_context_ = new net::TestURLRequestContextGetter(
+        content::BrowserThread::GetTaskRunnerForThread(
+            content::BrowserThread::IO));
+  }
+
+  net::URLRequestContextGetter* request_context() {
+    return request_context_.get();
+  }
+
+  // Helper to get files from our subdirectory in the general extensions test
+  // data dir.
+  base::FilePath GetTestPath(const base::FilePath& relative_path) {
+    base::FilePath base_path;
+    EXPECT_TRUE(PathService::Get(extensions::DIR_TEST_DATA, &base_path));
+    base_path = base_path.AppendASCII("content_hash_fetcher");
+    return base_path.Append(relative_path);
+  }
+
+  // Unzips the extension source from |extension_zip| into a temporary
+  // directory and loads it, returning the resuling Extension object.
+  scoped_refptr<Extension> UnzipToTempDirAndLoad(
+      const base::FilePath& extension_zip) {
+    EXPECT_TRUE(temp_dir_.CreateUniqueTempDir());
+    base::FilePath destination = temp_dir_.path();
+    EXPECT_TRUE(zip::Unzip(extension_zip, destination));
+
+    std::string error;
+    scoped_refptr<Extension> extension = file_util::LoadExtension(
+        destination, Manifest::INTERNAL, 0 /* flags */, &error);
+    EXPECT_NE(nullptr, extension.get()) << " error:'" << error << "'";
+    return extension;
+  }
+
+  // Registers interception of requests for |url| to respond with the contents
+  // of the file at |response_path|.
+  void RegisterInterception(const GURL& url,
+                            const base::FilePath& response_path) {
+    interceptor_ = base::MakeUnique<net::TestURLRequestInterceptor>(
+        url.scheme(), url.host(),
+        content::BrowserThread::GetTaskRunnerForThread(
+            content::BrowserThread::IO),
+        content::BrowserThread::GetBlockingPool());
+    interceptor_->SetResponse(url, response_path);
+  }
+
+ protected:
+  std::unique_ptr<content::TestBrowserThreadBundle> browser_threads_;
+  std::unique_ptr<net::TestURLRequestInterceptor> interceptor_;
+  scoped_refptr<net::TestURLRequestContextGetter> request_context_;
+  base::ScopedTempDir temp_dir_;
+};
+
+// This tests our ability to successfully fetch, parse, and validate a missing
+// verified_contents.json file for an extension.
+TEST_F(ContentHashFetcherTest, MissingVerifiedContents) {
+  // We unzip the extension source to a temp directory to simulate it being
+  // installed there, because the ContentHashFetcher will create the _metadata/
+  // directory within the extension install dir and write the fetched
+  // verified_contents.json file there.
+  base::FilePath test_dir_base = GetTestPath(
+      base::FilePath(FILE_PATH_LITERAL("missing_verified_contents")));
+  scoped_refptr<Extension> extension =
+      UnzipToTempDirAndLoad(test_dir_base.AppendASCII("source.zip"));
+
+  // Make sure there isn't already a verified_contents.json file there.
+  EXPECT_FALSE(
+      base::PathExists(file_util::GetVerifiedContentsPath(extension->path())));
+
+  MockDelegate delegate;
+  ContentHashFetcherWaiter waiter;
+  GURL fetch_url =
+      delegate.GetSignatureFetchUrl(extension->id(), *extension->version());
+
+  RegisterInterception(fetch_url,
+                       test_dir_base.AppendASCII("verified_contents.json"));
+
+  ContentHashFetcher fetcher(request_context(), &delegate,
+                             waiter.GetCallback());
+  fetcher.DoFetch(extension.get(), true /* force */);
+
+  // Make sure the fetch was successful.
+  std::unique_ptr<ContentHashFetcherResult> result = waiter.WaitForCallback();
+  ASSERT_TRUE(result.get());
+  EXPECT_TRUE(result->success);
+  EXPECT_TRUE(result->force);
+  EXPECT_TRUE(result->mismatch_paths.empty());
+
+  // Make sure the verified_contents.json file was written into the extension's
+  // install dir.
+  EXPECT_TRUE(
+      base::PathExists(file_util::GetVerifiedContentsPath(extension->path())));
+}
+
+// Similar to MissingVerifiedContents, but tests the case where the extension
+// actually has corruption.
+TEST_F(ContentHashFetcherTest, MissingVerifiedContentsAndCorrupt) {
+  base::FilePath test_dir_base =
+      GetTestPath(base::FilePath()).AppendASCII("missing_verified_contents");
+  scoped_refptr<Extension> extension =
+      UnzipToTempDirAndLoad(test_dir_base.AppendASCII("source.zip"));
+
+  // Tamper with a file in the extension.
+  base::FilePath script_path = extension->path().AppendASCII("script.js");
+  std::string addition = "//hello world";
+  ASSERT_TRUE(
+      base::AppendToFile(script_path, addition.c_str(), addition.size()));
+  MockDelegate delegate;
+  ContentHashFetcherWaiter waiter;
+  GURL fetch_url =
+      delegate.GetSignatureFetchUrl(extension->id(), *extension->version());
+
+  RegisterInterception(fetch_url,
+                       test_dir_base.AppendASCII("verified_contents.json"));
+
+  ContentHashFetcher fetcher(request_context(), &delegate,
+                             waiter.GetCallback());
+  fetcher.DoFetch(extension.get(), true /* force */);
+
+  // Make sure the fetch was *not* successful.
+  std::unique_ptr<ContentHashFetcherResult> result = waiter.WaitForCallback();
+  ASSERT_NE(nullptr, result.get());
+  EXPECT_TRUE(result->success);
+  EXPECT_TRUE(result->force);
+  EXPECT_TRUE(
+      base::ContainsKey(result->mismatch_paths, script_path.BaseName()));
+
+  // Make sure the verified_contents.json file was written into the extension's
+  // install dir.
+  EXPECT_TRUE(
+      base::PathExists(file_util::GetVerifiedContentsPath(extension->path())));
+}
+
+}  // namespace extensions