From 93bed14e13dd5a6dd3d68bcf6d3c7c1f691f669b Mon Sep 17 00:00:00 2001
From: Kristian Monsen <kristianm@google.com>
Date: Tue, 1 Nov 2011 14:30:59 +0000
Subject: Part of fix for bug 5523834, backporting cache fixes

This is hopefully a fix for bug 5255299

Cherry-picking CL
http://src.chromium.org/viewvc/chrome?view=rev&revision=92390

Change-Id: I2f9905bf2f53dd958eb17d1af789fcfb35224061
---
 net/base/net_error_list.h              |  3 ++-
 net/disk_cache/block_files.cc          |  6 ++++++
 net/disk_cache/block_files.h           |  1 +
 net/disk_cache/block_files_unittest.cc | 26 +++++++++++++++++++++++++-
 net/disk_cache/file_posix.cc           |  5 +++--
 net/disk_cache/file_win.cc             |  3 ++-
 6 files changed, 39 insertions(+), 5 deletions(-)

diff --git a/net/base/net_error_list.h b/net/base/net_error_list.h
index 6cdfa06..9e9a980 100644
--- a/net/base/net_error_list.h
+++ b/net/base/net_error_list.h
@@ -453,7 +453,8 @@ NET_ERROR(CACHE_MISS, -400)
 // Unable to read from the disk cache.
 NET_ERROR(CACHE_READ_FAILURE, -401)
 
-// ****NOTE THAT code -402 is available****
+// Unable to write to the disk cache.
+NET_ERROR(CACHE_WRITE_FAILURE, -402)
 
 // The operation is not supported for this entry.
 NET_ERROR(CACHE_OPERATION_NOT_SUPPORTED, -403)
diff --git a/net/disk_cache/block_files.cc b/net/disk_cache/block_files.cc
index faa9706..e39ca13 100644
--- a/net/disk_cache/block_files.cc
+++ b/net/disk_cache/block_files.cc
@@ -419,6 +419,12 @@ bool BlockFiles::OpenBlockFile(int index) {
       return false;
   }
 
+  if (static_cast<int>(file_len) <
+      header->max_entries * header->entry_size + kBlockHeaderSize) {
+    LOG(ERROR) << "File too small " << name.value();
+    return false;
+  }
+
   if (index == 0) {
     // Load the links file into memory with a single read.
     scoped_array<char> buf(new char[file_len]);
diff --git a/net/disk_cache/block_files.h b/net/disk_cache/block_files.h
index 5f1fa3c..6123c91 100644
--- a/net/disk_cache/block_files.h
+++ b/net/disk_cache/block_files.h
@@ -92,6 +92,7 @@ class BlockFiles {
   scoped_ptr<base::ThreadChecker> thread_checker_;
 
   FRIEND_TEST_ALL_PREFIXES(DiskCacheTest, BlockFiles_ZeroSizeFile);
+  FRIEND_TEST_ALL_PREFIXES(DiskCacheTest, BlockFiles_TruncatedFile);
   FRIEND_TEST_ALL_PREFIXES(DiskCacheTest, BlockFiles_InvalidFile);
   FRIEND_TEST_ALL_PREFIXES(DiskCacheTest, BlockFiles_Stats);
 
diff --git a/net/disk_cache/block_files_unittest.cc b/net/disk_cache/block_files_unittest.cc
index 90bf048..7ee08d3 100644
--- a/net/disk_cache/block_files_unittest.cc
+++ b/net/disk_cache/block_files_unittest.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -177,6 +177,30 @@ TEST_F(DiskCacheTest, BlockFiles_ZeroSizeFile) {
   ASSERT_FALSE(files.Init(false));
 }
 
+// Handling of truncated files (non empty).
+TEST_F(DiskCacheTest, BlockFiles_TruncatedFile) {
+  FilePath path = GetCacheFilePath();
+  ASSERT_TRUE(DeleteCache(path));
+  ASSERT_TRUE(file_util::CreateDirectory(path));
+
+  BlockFiles files(path);
+  ASSERT_TRUE(files.Init(true));
+  Addr address;
+  EXPECT_TRUE(files.CreateBlock(RANKINGS, 2, &address));
+
+  FilePath filename = files.Name(0);
+  files.CloseFiles();
+  // Truncate one of the files.
+  {
+    scoped_refptr<File> file(new File);
+    ASSERT_TRUE(file->Init(filename));
+    EXPECT_TRUE(file->SetLength(15000));
+  }
+
+  // Initializing should fail, not crash.
+  ASSERT_FALSE(files.Init(false));
+}
+
 // An invalid file can be detected after init.
 TEST_F(DiskCacheTest, BlockFiles_InvalidFile) {
   FilePath path = GetCacheFilePath();
diff --git a/net/disk_cache/file_posix.cc b/net/disk_cache/file_posix.cc
index 087ff13..71fc1fb 100644
--- a/net/disk_cache/file_posix.cc
+++ b/net/disk_cache/file_posix.cc
@@ -8,6 +8,7 @@
 
 #include "base/logging.h"
 #include "base/threading/worker_pool.h"
+#include "net/base/net_errors.h"
 #include "net/disk_cache/disk_cache.h"
 #include "net/disk_cache/in_flight_io.h"
 
@@ -92,7 +93,7 @@ void FileBackgroundIO::Read() {
   if (file_->Read(const_cast<void*>(buf_), buf_len_, offset_)) {
     result_ = static_cast<int>(buf_len_);
   } else {
-    result_ = -1;
+    result_ = net::ERR_CACHE_READ_FAILURE;
   }
   controller_->OnIOComplete(this);
 }
@@ -101,7 +102,7 @@ void FileBackgroundIO::Read() {
 void FileBackgroundIO::Write() {
   bool rv = file_->Write(buf_, buf_len_, offset_);
 
-  result_ = rv ? static_cast<int>(buf_len_) : -1;
+  result_ = rv ? static_cast<int>(buf_len_) : net::ERR_CACHE_WRITE_FAILURE;
   controller_->OnIOComplete(this);
 }
 
diff --git a/net/disk_cache/file_win.cc b/net/disk_cache/file_win.cc
index 737b8e8..ed93511 100644
--- a/net/disk_cache/file_win.cc
+++ b/net/disk_cache/file_win.cc
@@ -7,6 +7,7 @@
 #include "base/file_path.h"
 #include "base/lazy_instance.h"
 #include "base/message_loop.h"
+#include "net/base/net_errors.h"
 #include "net/disk_cache/disk_cache.h"
 
 namespace {
@@ -42,7 +43,7 @@ void CompletionHandler::OnIOCompleted(MessageLoopForIO::IOContext* context,
 
   if (error) {
     DCHECK(!actual_bytes);
-    actual_bytes = static_cast<DWORD>(-1);
+    actual_bytes = static_cast<DWORD>(net::ERR_CACHE_READ_FAILURE);
     NOTREACHED();
   }
 
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