[Downloads] Avoid resetting SecureHash state across an interruption.

DownloadFileImpl/BaseFile was causing the SecureHash object to be
finalized when a download was interrupted. This caused the hash state to
be incorrect and subsequently the hash resulting from resuming the
download was also incorrect.

BUG=7648
BUG=581164

Review URL: https://codereview.chromium.org/1591523002

Cr-Commit-Position: refs/heads/master@{#371428}

content/browser/download/base_file.cc

@@ -203,7 +203,11 @@ void BaseFile::Finish() {
 
   if (calculate_hash_)
     secure_hash_->Finish(sha256_hash_, crypto::kSHA256Length);
+  Close();
+}
 
+void BaseFile::FinishWithError() {
+  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
   Close();
 }
 

content/browser/download/base_file.h

@@ -75,6 +75,11 @@ class CONTENT_EXPORT BaseFile {
   // Indicate that the download has finished. No new data will be received.
   void Finish();
 
+  // Indicate that the download is being aborted due to an error. This is
+  // identical to Finish() with the exception that the hash state will not be
+  // finalized.
+  void FinishWithError();
+
   // Set the client guid which will be used to identify the app to the
   // system AV scanning function. Should be called before
   // AnnotateWithSourceInformation() to take effect.

content/browser/download/download_browsertest.cc

@@ -383,6 +383,8 @@ class TestShellDownloadManagerDelegate : public ShellDownloadManagerDelegate {
     return true;
   }
 
+  bool GenerateFileHash() override { return true; }
+
   void SetDelayedOpen(bool delay) {
     delay_download_open_ = delay;
   }
@@ -1399,6 +1401,59 @@ IN_PROC_BROWSER_TEST_P(DownloadResumptionContentTest,
   EXPECT_EQ(download->GetState(), DownloadItem::COMPLETE);
 }
 
+IN_PROC_BROWSER_TEST_P(DownloadResumptionContentTest, Resume_Hash) {
+  using InjectedError = TestDownloadRequestHandler::InjectedError;
+  const char kExpectedHash[] =
+      "\xa7\x44\x49\x86\x24\xc6\x84\x6c\x89\xdf\xd8\xec\xa0\xe0\x61\x12\xdc\x80"
+      "\x13\xf2\x83\x49\xa9\x14\x52\x32\xf0\x95\x20\xca\x5b\x30";
+  std::string expected_hash(kExpectedHash);
+  TestDownloadRequestHandler request_handler;
+  TestDownloadRequestHandler::Parameters parameters;
+
+  // As a control, let's try GetHash() on an uninterrupted download.
+  request_handler.StartServing(parameters);
+  DownloadItem* uninterrupted_download(StartDownloadAndReturnItem(
+      initiator_shell_for_resumption(), request_handler.url()));
+  WaitForCompletion(uninterrupted_download);
+  EXPECT_EQ(expected_hash, uninterrupted_download->GetHash());
+
+  // Now with interruptions.
+  parameters.injected_errors.push(
+      InjectedError(100, net::ERR_CONNECTION_RESET));
+  parameters.injected_errors.push(
+      InjectedError(211, net::ERR_CONNECTION_RESET));
+  parameters.injected_errors.push(
+      InjectedError(337, net::ERR_CONNECTION_RESET));
+  parameters.injected_errors.push(
+      InjectedError(400, net::ERR_CONNECTION_RESET));
+  parameters.injected_errors.push(
+      InjectedError(512, net::ERR_CONNECTION_RESET));
+  request_handler.StartServing(parameters);
+
+  // Start and watch for interrupt.
+  DownloadItem* download(StartDownloadAndReturnItem(
+      initiator_shell_for_resumption(), request_handler.url()));
+  WaitForInterrupt(download);
+
+  PrepareToResume();
+  download->Resume();
+  WaitForInterrupt(download);
+
+  download->Resume();
+  WaitForInterrupt(download);
+
+  download->Resume();
+  WaitForInterrupt(download);
+
+  download->Resume();
+  WaitForInterrupt(download);
+
+  download->Resume();
+  WaitForCompletion(download);
+
+  EXPECT_EQ(expected_hash, download->GetHash());
+}
+
 // An interrupted download should remove the intermediate file when it is
 // cancelled.
 IN_PROC_BROWSER_TEST_P(DownloadResumptionContentTest,

content/browser/download/download_file_impl.cc

@@ -280,7 +280,10 @@ void DownloadFileImpl::StreamActive() {
               stream_reader_->GetStatus());
           SendUpdate();
           base::TimeTicks close_start(base::TimeTicks::Now());
-          file_.Finish();
+          if (reason == DOWNLOAD_INTERRUPT_REASON_NONE)
+            file_.Finish();
+          else
+            file_.FinishWithError();
           base::TimeTicks now(base::TimeTicks::Now());
           disk_writes_time_ += (now - close_start);
           RecordFileBandwidth(