Restrict WEBM Key ID data to 128-bits for Android

content/browser/media/cdm/browser_cdm_manager.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 "content/browser/media/cdm/browser_cdm_manager.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/lazy_instance.h"
@@ skipping 18 matching lines @@
 #include "content/public/common/renderer_preferences.h"
 #endif
 
 namespace content {
 
 using media::BrowserCdm;
 using media::MediaKeys;
 
 namespace {
 
+#if defined(OS_ANDROID)
+// Android only supports 128-bit key IDs.
+const size_t kAndroidMaxKeyIdLengthForWebM = 128 / 8;

[ddorwin, 2015/05/15 04:12:35]

I believe this key ID length applies to all containers, not just WebM. And, it's
an exact length, not a max.
Also, it's nice to include the units in the name.
Thus, something like kAndroidKeyIdBytes.

[jrummell, 2015/05/15 16:41:19]

Done.

+#endif
+
 // The ID used in this class is a concatenation of |render_frame_id| and
 // |cdm_id|, i.e. (render_frame_id << 32) + cdm_id.
 
 uint64 GetId(int render_frame_id, int cdm_id) {
   return (static_cast<uint64>(render_frame_id) << 32) +
          static_cast<uint64>(cdm_id);
 }
 
 bool IdBelongsToFrame(uint64 id, int render_frame_id) {
   return (id >> 32) == static_cast<uint64>(render_frame_id);
@@ skipping 289 matching lines @@
 
   scoped_ptr<NewSessionPromise> promise(
       new NewSessionPromise(this, render_frame_id, cdm_id, promise_id));
 
   if (init_data.size() > media::limits::kMaxInitDataLength) {
     LOG(WARNING) << "InitData for ID: " << cdm_id
                  << " too long: " << init_data.size();
     promise->reject(MediaKeys::INVALID_ACCESS_ERROR, 0, "Init data too long.");
     return;
   }
+#if defined(OS_ANDROID)
+  if (init_data_type == INIT_DATA_TYPE_WEBM &&
+      init_data.size() > kAndroidMaxKeyIdLengthForWebM) {

[ddorwin, 2015/05/15 04:12:35]

s/>/!=/

Then update the message too.

[jrummell, 2015/05/15 16:41:19]

Done.

+    promise->reject(MediaKeys::INVALID_ACCESS_ERROR, 0,
+                    "'webm' initData is too long.");
+    return;
+  }
+#endif
 
   media::EmeInitDataType eme_init_data_type;
   switch (init_data_type) {
     case INIT_DATA_TYPE_WEBM:
       eme_init_data_type = media::EmeInitDataType::WEBM;
       break;
 #if defined(USE_PROPRIETARY_CODECS)
     case INIT_DATA_TYPE_CENC:
       eme_init_data_type = media::EmeInitDataType::CENC;
       break;
@@ skipping 220 matching lines @@
   }
 
   // Only the temporary session type is supported in browser CDM path.
   // TODO(xhwang): Add SessionType support if needed.
   cdm->CreateSessionAndGenerateRequest(media::MediaKeys::TEMPORARY_SESSION,
                                        init_data_type, init_data,
                                        promise.Pass());
 }
 
 }  // namespace content