AU: Verify source rootfs/kernel hashes before applying delta.

download_action.cc

 // Copyright (c) 2010 The Chromium OS 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 "update_engine/download_action.h"
 #include <errno.h>
 #include <algorithm>
 #include <string>
 #include <vector>
 #include <glib.h>
@@ skipping 46 matching lines @@
                               rootfs_buffered_file_writer_.get()));
       split_file_writer_->SetFirstOpenArgs(
           install_plan_.kernel_install_path.c_str(),
           O_WRONLY | O_CREAT | O_TRUNC | O_LARGEFILE,
           0644);
       decompressing_file_writer_.reset(
           new GzipDecompressingFileWriter(split_file_writer_.get()));
       writer_ = decompressing_file_writer_.get();
     } else {
       delta_performer_.reset(new DeltaPerformer(prefs_));
+      delta_performer_->set_current_kernel_hash(
+          &install_plan_.current_kernel_hash);
+      delta_performer_->set_current_rootfs_hash(
+          &install_plan_.current_rootfs_hash);
       writer_ = delta_performer_.get();
     }
   }
   int rc = writer_->Open(install_plan_.install_path.c_str(),
                          O_TRUNC | O_WRONLY | O_CREAT | O_LARGEFILE,
                          0644);
   if (rc < 0) {
     LOG(ERROR) << "Unable to open output file " << install_plan_.install_path;
     // report error to processor
     processor_->ActionComplete(this, kActionCodeInstallDeviceOpenError);
     return;
   }
   if (!install_plan_.is_full_update) {
     if (!delta_performer_->OpenKernel(
             install_plan_.kernel_install_path.c_str())) {
       LOG(ERROR) << "Unable to open kernel file "
                  << install_plan_.kernel_install_path.c_str();
       writer_->Close();
       processor_->ActionComplete(this, kActionCodeKernelDeviceOpenError);
       return;
     }
   }
   if (delegate_) {
     delegate_->SetDownloadStatus(true);  // Set to active.
   }
   http_fetcher_->BeginTransfer(install_plan_.download_url);
 }
 
 void DownloadAction::TerminateProcessing() {
-  CHECK(writer_);
-  CHECK_EQ(writer_->Close(), 0);
-  writer_ = NULL;
+  if (writer_) {
+    LOG_IF(WARNING, writer_->Close() != 0) << "Error closing the writer.";
+    writer_ = NULL;
+  }
   http_fetcher_->TerminateTransfer();
   if (delegate_) {
     delegate_->SetDownloadStatus(false);  // Set to inactive.
   }
 }
 
 void DownloadAction::ReceivedBytes(HttpFetcher *fetcher,
                                    const char* bytes,
                                    int length) {
   bytes_received_ += length;
   if (delegate_)
     delegate_->BytesReceived(bytes_received_, install_plan_.size);
-  int rc = writer_->Write(bytes, length);
-  TEST_AND_RETURN(rc >= 0);
+  if (writer_ && writer_->Write(bytes, length) < 0) {
+    LOG(ERROR) << "Write error -- terminating processing.";
+    TerminateProcessing();
+    processor_->ActionComplete(this, kActionCodeDownloadWriteError);
+    return;
+  }
   omaha_hash_calculator_.Update(bytes, length);
 }
 
 namespace {
 void FlushLinuxCaches() {
   vector<string> command;
   command.push_back("/bin/sync");
   int rc;
   LOG(INFO) << "FlushLinuxCaches-sync...";
   Subprocess::SynchronousExec(command, &rc);
   LOG(INFO) << "FlushLinuxCaches-drop_caches...";
 
   const char* const drop_cmd = "3\n";
   utils::WriteFile("/proc/sys/vm/drop_caches", drop_cmd, strlen(drop_cmd));
 
   LOG(INFO) << "FlushLinuxCaches done.";
 }
 }
 
 void DownloadAction::TransferComplete(HttpFetcher *fetcher, bool successful) {
   if (writer_) {
-    CHECK_EQ(writer_->Close(), 0) << errno;
+    LOG_IF(WARNING, writer_->Close() != 0) << "Error closing the writer.";
     writer_ = NULL;
   }
   if (delegate_) {
     delegate_->SetDownloadStatus(false);  // Set to inactive.
   }
   ActionExitCode code =
       successful ? kActionCodeSuccess : kActionCodeDownloadTransferError;
   if (code == kActionCodeSuccess) {
     if (!install_plan_.is_full_update) {
       if (!delta_performer_->VerifyPayload("",
@@ skipping 27 matching lines @@
 
   FlushLinuxCaches();
 
   // Write the path to the output pipe if we're successful.
   if (code == kActionCodeSuccess && HasOutputPipe())
     SetOutputObject(GetInputObject());
   processor_->ActionComplete(this, code);
 }
 
 };  // namespace {}