[CacheStorage] Pad and bin opaque resource sizes.

content/browser/cache_storage/cache_storage.cc

Index: content/browser/cache_storage/cache_storage.cc
diff --git a/content/browser/cache_storage/cache_storage.cc b/content/browser/cache_storage/cache_storage.cc
index f6466e612798c970b9f552294a3bce621f12c547..7ddc75a2e763ba22d70b411f07e7bb4233ec6206 100644
--- a/content/browser/cache_storage/cache_storage.cc
+++ b/content/browser/cache_storage/cache_storage.cc
@@ -14,6 +14,7 @@
 #include "base/files/file_util.h"
 #include "base/files/memory_mapped_file.h"
 #include "base/guid.h"
+#include "base/lazy_instance.h"
 #include "base/location.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/ref_counted.h"
@@ -32,16 +33,44 @@
 #include "content/browser/cache_storage/cache_storage_index.h"
 #include "content/browser/cache_storage/cache_storage_scheduler.h"
 #include "content/public/browser/browser_thread.h"
+#include "crypto/symmetric_key.h"
 #include "net/base/directory_lister.h"
 #include "net/base/net_errors.h"
 #include "net/url_request/url_request_context_getter.h"
 #include "storage/browser/blob/blob_storage_context.h"
 #include "storage/browser/quota/quota_manager_proxy.h"
 
+using base::LazyInstance;
+using crypto::SymmetricKey;
+
 namespace content {
 
 namespace {
 
+const SymmetricKey::Algorithm kPaddingKeyAlgorithm = SymmetricKey::AES;
+
+// LazyInstance needs a new-able type so this class exists solely to "own"
+// a SymmetricKey.
+class KeyOwner {

[jkarlin, 2017/07/31 14:03:24]

optional nit: SymmetricKeyOwner?

[cmumford, 2017/08/10 16:37:10]

Done.

+ public:
+  std::unique_ptr<SymmetricKey> CreateDuplicate() const {
+    return SymmetricKey::Import(kPaddingKeyAlgorithm, key());
+  }
+
+  // Only for test purposes.
+  void GenerateNew() {
+    key_ = SymmetricKey::GenerateRandomKey(kPaddingKeyAlgorithm, 128);
+  }
+
+  const std::string& key() const { return key_->key(); }
+
+ private:
+  std::unique_ptr<SymmetricKey> key_ =
+      SymmetricKey::GenerateRandomKey(kPaddingKeyAlgorithm, 128);
+};
+
+static LazyInstance<KeyOwner>::Leaky s_padding_key = LAZY_INSTANCE_INITIALIZER;
+
 std::string HexedHash(const std::string& value) {
   std::string value_hash = base::SHA1HashString(value);
   std::string valued_hexed_hash = base::ToLowerASCII(
@@ -57,6 +86,10 @@ void SizeRetrievedFromAllCaches(std::unique_ptr<int64_t> accumulator,
 
 void DoNothingWithBool(bool success) {}
 
+std::unique_ptr<SymmetricKey> ImportPaddingKey(const std::string& raw_key) {
+  return SymmetricKey::Import(kPaddingKeyAlgorithm, raw_key);
+}
+
 }  // namespace
 
 const char CacheStorage::kIndexFileName[] = "index.txt";
@@ -102,7 +135,9 @@ class CacheStorage::CacheLoader {
   // load the backend, that happens lazily when the cache is used.
   virtual std::unique_ptr<CacheStorageCache> CreateCache(
       const std::string& cache_name,
-      int64_t cache_size) = 0;
+      int64_t cache_size,
+      int64_t cache_padding,
+      std::unique_ptr<SymmetricKey> cache_padding_key) = 0;
 
   // Deletes any pre-existing cache of the same name and then loads it.
   virtual void PrepareNewCacheDestination(const std::string& cache_name,
@@ -164,17 +199,22 @@ class CacheStorage::MemoryLoader : public CacheStorage::CacheLoader {
                     cache_storage,
                     origin) {}
 
-  std::unique_ptr<CacheStorageCache> CreateCache(const std::string& cache_name,
-                                                 int64_t cache_size) override {
+  std::unique_ptr<CacheStorageCache> CreateCache(
+      const std::string& cache_name,
+      int64_t cache_size,
+      int64_t cache_padding,
+      std::unique_ptr<SymmetricKey> cache_padding_key) override {
     return CacheStorageCache::CreateMemoryCache(
         origin_, cache_name, cache_storage_, request_context_getter_,
-        quota_manager_proxy_, blob_context_);
+        quota_manager_proxy_, blob_context_,
+        s_padding_key.Get().CreateDuplicate());
   }
 
   void PrepareNewCacheDestination(const std::string& cache_name,
                                   CacheCallback callback) override {
     std::unique_ptr<CacheStorageCache> cache =
-        CreateCache(cache_name, 0 /*cache_size*/);
+        CreateCache(cache_name, 0 /*cache_size*/, 0 /* cache_padding */,
+                    s_padding_key.Get().CreateDuplicate());
     std::move(callback).Run(std::move(cache));
   }
 
@@ -232,8 +272,11 @@ class CacheStorage::SimpleCacheLoader : public CacheStorage::CacheLoader {
         origin_path_(origin_path),
         weak_ptr_factory_(this) {}
 
-  std::unique_ptr<CacheStorageCache> CreateCache(const std::string& cache_name,
-                                                 int64_t cache_size) override {
+  std::unique_ptr<CacheStorageCache> CreateCache(
+      const std::string& cache_name,
+      int64_t cache_size,
+      int64_t cache_padding,
+      std::unique_ptr<SymmetricKey> cache_padding_key) override {
     DCHECK_CURRENTLY_ON(BrowserThread::IO);
     DCHECK(base::ContainsKey(cache_name_to_cache_dir_, cache_name));
 
@@ -242,7 +285,7 @@ class CacheStorage::SimpleCacheLoader : public CacheStorage::CacheLoader {
     return CacheStorageCache::CreatePersistentCache(
         origin_, cache_name, cache_storage_, cache_path,
         request_context_getter_, quota_manager_proxy_, blob_context_,
-        cache_size);
+        cache_size, cache_padding, std::move(cache_padding_key));
   }
 
   void PrepareNewCacheDestination(const std::string& cache_name,
@@ -280,8 +323,9 @@ class CacheStorage::SimpleCacheLoader : public CacheStorage::CacheLoader {
     }
 
     cache_name_to_cache_dir_[cache_name] = cache_dir;
-    std::move(callback).Run(
-        CreateCache(cache_name, CacheStorage::kSizeUnknown));
+    std::move(callback).Run(CreateCache(cache_name, CacheStorage::kSizeUnknown,
+                                        CacheStorage::kSizeUnknown,
+                                        s_padding_key.Get().CreateDuplicate()));
   }
 
   void CleanUpDeletedCache(CacheStorageCache* cache) override {
@@ -322,6 +366,10 @@ class CacheStorage::SimpleCacheLoader : public CacheStorage::CacheLoader {
         index_cache->clear_size();
       else
         index_cache->set_size(cache_metadata.size);
+      index_cache->set_padding_key(cache_metadata.padding_key);
+      index_cache->set_padding(cache_metadata.padding);
+      index_cache->set_padding_version(
+          CacheStorageCache::GetResponsePaddingVersion());
     }
 
     std::string serialized;
@@ -376,7 +424,28 @@ class CacheStorage::SimpleCacheLoader : public CacheStorage::CacheLoader {
       DCHECK(cache.has_cache_dir());
       int64_t cache_size =
           cache.has_size() ? cache.size() : CacheStorage::kSizeUnknown;
-      index->Insert(CacheStorageIndex::CacheMetadata(cache.name(), cache_size));
+      int64_t cache_padding;
+      if (cache.has_padding()) {
+        if (cache.has_padding_version() &&
+            cache.padding_version() ==
+                CacheStorageCache::GetResponsePaddingVersion()) {
+          cache_padding = cache.padding();
+        } else {
+          // The padding algorithm version changed so set to unknown to force
+          // recalculation.
+          cache_padding = CacheStorage::kSizeUnknown;
+        }
+      } else {
+        cache_padding = CacheStorage::kSizeUnknown;
+      }
+
+      std::string cache_padding_key = cache.has_padding_key()
+                                          ? cache.padding_key()
+                                          : s_padding_key.Get().key();
+
+      index->Insert(CacheStorageIndex::CacheMetadata(
+          cache.name(), cache_size, cache_padding,
+          std::move(cache_padding_key)));
       cache_name_to_cache_dir_[cache.name()] = cache.cache_dir();
       cache_dirs->insert(cache.cache_dir());
     }
@@ -687,11 +756,14 @@ bool CacheStorage::InitiateScheduledIndexWriteForTest(
 }
 
 void CacheStorage::CacheSizeUpdated(const CacheStorageCache* cache,
-                                    int64_t size) {
+                                    int64_t padded_size) {
   // Should not be called for doomed caches.
   DCHECK(!base::ContainsKey(doomed_caches_,
                             const_cast<CacheStorageCache*>(cache)));
-  cache_index_->SetCacheSize(cache->cache_name(), size);
+  DCHECK_NE(cache->cache_padding(), kSizeUnknown);
+  cache_index_->SetCacheSize(cache->cache_name(),
+                             padded_size - cache->cache_padding());

[jkarlin, 2017/07/31 14:03:24]

I'd rather both sizes (padded and cache) were supplied to this function as
arguments, or neither. You can always use cache->cache_size() and
cache->cache_padding().

[cmumford, 2017/08/10 16:37:10]

You're right - way nicer that way.

+  cache_index_->SetCachePadding(cache->cache_name(), cache->cache_padding());
   ScheduleWriteIndex();
 }
 
@@ -703,6 +775,11 @@ void CacheStorage::CompleteAsyncOperationForTesting() {
   scheduler_->CompleteOperationAndRunNext();
 }
 
+// static
+void CacheStorage::GenerateNewKeyForTesting() {
+  s_padding_key.Get().GenerateNew();
+}
+
 // Init is run lazily so that it is called on the proper MessageLoop.
 void CacheStorage::LazyInit() {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
@@ -784,8 +861,9 @@ void CacheStorage::CreateCacheDidCreateCache(
   CacheStorageCache* cache_ptr = cache.get();
 
   cache_map_.insert(std::make_pair(cache_name, std::move(cache)));
-  cache_index_->Insert(
-      CacheStorageIndex::CacheMetadata(cache_name, cache_ptr->cache_size()));
+  cache_index_->Insert(CacheStorageIndex::CacheMetadata(
+      cache_name, cache_ptr->cache_size(), cache_ptr->cache_padding(),
+      cache_ptr->cache_padding_key()->key()));
 
   cache_loader_->WriteIndex(
       *cache_index_,
@@ -1035,8 +1113,12 @@ std::unique_ptr<CacheStorageCacheHandle> CacheStorage::GetLoadedCache(
   CacheStorageCache* cache = map_iter->second.get();
 
   if (!cache) {
+    const CacheStorageIndex::CacheMetadata* metadata =
+        cache_index_->GetMetadata(cache_name);
+    DCHECK(metadata);
     std::unique_ptr<CacheStorageCache> new_cache = cache_loader_->CreateCache(
-        cache_name, cache_index_->GetCacheSize(cache_name));
+        cache_name, metadata->size, metadata->padding,
+        ImportPaddingKey(metadata->padding_key));
     CacheStorageCache* cache_ptr = new_cache.get();
     map_iter->second = std::move(new_cache);
 
@@ -1083,10 +1165,10 @@ void CacheStorage::SizeImpl(SizeCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   DCHECK(initialized_);
 
-  if (cache_index_->GetStorageSize() != kSizeUnknown) {
+  if (cache_index_->GetPaddedStorageSize() != kSizeUnknown) {
     base::ThreadTaskRunnerHandle::Get()->PostTask(
-        FROM_HERE,
-        base::BindOnce(std::move(callback), cache_index_->GetStorageSize()));
+        FROM_HERE, base::BindOnce(std::move(callback),
+                                  cache_index_->GetPaddedStorageSize()));
     return;
   }