Fix several problems with the content verification code

extensions/browser/content_verify_job.cc

 // Copyright 2014 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 "extensions/browser/content_verify_job.h"
 
 #include <algorithm>
 
 #include "base/stl_util.h"
 #include "base/task_runner_util.h"
@@ skipping 11 matching lines @@
 }  // namespace
 
 ContentVerifyJob::ContentVerifyJob(ContentHashReader* hash_reader,
                                    const FailureCallback& failure_callback)
     : done_reading_(false),
       hashes_ready_(false),
       total_bytes_read_(0),
       current_block_(0),
       current_hash_byte_count_(0),
       hash_reader_(hash_reader),
-      failure_callback_(failure_callback) {
+      failure_callback_(failure_callback),
+      failed_(false) {
   // It's ok for this object to be constructed on a different thread from where
   // it's used.
   thread_checker_.DetachFromThread();
 }
 
 ContentVerifyJob::~ContentVerifyJob() {
 }
 
 void ContentVerifyJob::Start() {
   DCHECK(thread_checker_.CalledOnValidThread());
   base::PostTaskAndReplyWithResult(
       content::BrowserThread::GetBlockingPool(),
       FROM_HERE,
       base::Bind(&ContentHashReader::Init, hash_reader_),
       base::Bind(&ContentVerifyJob::OnHashesReady, this));
 }
 
 void ContentVerifyJob::BytesRead(int count, const char* data) {
   DCHECK(thread_checker_.CalledOnValidThread());
+  if (failed_)
+    return;
   if (g_test_delegate) {
     FailureReason reason =
         g_test_delegate->BytesRead(hash_reader_->extension_id(), count, data);
     if (reason != NONE)
       return DispatchFailureCallback(reason);
   }
   if (!hashes_ready_) {
     queue_.append(data, count);
     return;
   }
   DCHECK_GE(count, 0);
   int bytes_added = 0;
 
   while (bytes_added < count) {
     if (current_block_ >= hash_reader_->block_count())
       return DispatchFailureCallback(HASH_MISMATCH);
 
     if (!current_hash_.get()) {
       current_hash_byte_count_ = 0;
       current_hash_.reset(
           crypto::SecureHash::Create(crypto::SecureHash::SHA256));
     }
     // Compute how many bytes we should hash, and add them to the current hash.
     int bytes_to_hash =
         std::min(hash_reader_->block_size() - current_hash_byte_count_,
                  count - bytes_added);
+    DCHECK(bytes_to_hash > 0);
     current_hash_->Update(data + bytes_added, bytes_to_hash);
     bytes_added += bytes_to_hash;
     current_hash_byte_count_ += bytes_to_hash;
     total_bytes_read_ += bytes_to_hash;
 
     // If we finished reading a block worth of data, finish computing the hash
     // for it and make sure the expected hash matches.
-    if (current_hash_byte_count_ == hash_reader_->block_size())
-      FinishBlock();
+    if (current_hash_byte_count_ == hash_reader_->block_size() &&
+        !FinishBlock()) {
+      DispatchFailureCallback(HASH_MISMATCH);
+      return;
+    }
   }
 }
 
 void ContentVerifyJob::DoneReading() {
   DCHECK(thread_checker_.CalledOnValidThread());
+  if (failed_)
+    return;
   if (g_test_delegate) {
     FailureReason reason =
         g_test_delegate->DoneReading(hash_reader_->extension_id());
     if (reason != NONE) {
       DispatchFailureCallback(reason);
       return;
     }
   }
   done_reading_ = true;
-  if (hashes_ready_)
-    FinishBlock();
+  if (hashes_ready_ && !FinishBlock())
+    DispatchFailureCallback(HASH_MISMATCH);
 }
 
-void ContentVerifyJob::FinishBlock() {
+bool ContentVerifyJob::FinishBlock() {
   if (current_hash_byte_count_ <= 0)
-    return;
+    return true;
   std::string final(crypto::kSHA256Length, 0);
   current_hash_->Finish(string_as_array(&final), final.size());
 
   const std::string* expected_hash = NULL;
-  if (!hash_reader_->GetHashForBlock(current_block_, &expected_hash))
-    return DispatchFailureCallback(HASH_MISMATCH);
-
-  if (*expected_hash != final)
-    return DispatchFailureCallback(HASH_MISMATCH);
+  if (!hash_reader_->GetHashForBlock(current_block_, &expected_hash) ||
+      *expected_hash != final)
+    return false;
 
   current_hash_.reset();
   current_hash_byte_count_ = 0;
   current_block_++;
+  return true;
 }
 
 void ContentVerifyJob::OnHashesReady(bool success) {
-  if (!success && !g_test_delegate)
-    return DispatchFailureCallback(NO_HASHES);
+  if (!success && !g_test_delegate) {
+    if (hash_reader_->have_verified_contents() &&
+        hash_reader_->have_computed_hashes())
+      DispatchFailureCallback(NO_HASHES_FOR_FILE);
+    else
+      DispatchFailureCallback(MISSING_ALL_HASHES);
+    return;
+  }
 
   hashes_ready_ = true;
   if (!queue_.empty()) {
     std::string tmp;
     queue_.swap(tmp);
     BytesRead(tmp.size(), string_as_array(&tmp));
   }
-  if (done_reading_)
-    FinishBlock();
+  if (done_reading_ && !FinishBlock())
+    DispatchFailureCallback(HASH_MISMATCH);
 }
 
 // static
 void ContentVerifyJob::SetDelegateForTests(TestDelegate* delegate) {
   g_test_delegate = delegate;
 }
 
 void ContentVerifyJob::DispatchFailureCallback(FailureReason reason) {
+  DCHECK(!failed_);
+  failed_ = true;
   if (!failure_callback_.is_null()) {
+    VLOG(1) << "job failed for " << hash_reader_->extension_id() << " "
+            << hash_reader_->relative_path().MaybeAsASCII()
+            << " reason:" << reason;
     failure_callback_.Run(reason);
     failure_callback_.Reset();
   }
 }
 
 }  // namespace extensions