Improve data sanitization of initialization data

media/blink/webcontentdecryptionmodulesession_impl.cc

 // Copyright 2013 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 "webcontentdecryptionmodulesession_impl.h"
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
 #include "base/logging.h"
 #include "base/numerics/safe_conversions.h"
@@ skipping 86 matching lines @@
 
   NOTREACHED();
   return MediaKeys::TEMPORARY_SESSION;
 }
 
 static bool SanitizeInitData(EmeInitDataType init_data_type,
                              const unsigned char* init_data,
                              size_t init_data_length,
                              std::vector<uint8_t>* sanitized_init_data,
                              std::string* error_message) {
+  DCHECK_GT(init_data_length, 0u);
   if (init_data_length > limits::kMaxInitDataLength) {
     error_message->assign("Initialization data too long.");
     return false;
   }
 
   switch (init_data_type) {
     case EmeInitDataType::WEBM:
+      // |init_data| for WebM is a single key.
+      if (init_data_length > limits::kMaxKeyIdLength) {
+        error_message->assign("Initialization data for WebM is too long.");
+        return false;
+      }
       sanitized_init_data->assign(init_data, init_data + init_data_length);
       return true;
 
     case EmeInitDataType::CENC:
 #if defined(USE_PROPRIETARY_CODECS)
       sanitized_init_data->assign(init_data, init_data + init_data_length);
       if (!ValidatePsshInput(*sanitized_init_data)) {
         error_message->assign("Initialization data for CENC is incorrect.");
         return false;
       }
@@ skipping 307 matching lines @@
 
   DCHECK(session_id_.empty()) << "Session ID may not be changed once set.";
   session_id_ = session_id;
   *status =
       adapter_->RegisterSession(session_id_, weak_ptr_factory_.GetWeakPtr())
           ? SessionInitStatus::NEW_SESSION
           : SessionInitStatus::SESSION_ALREADY_EXISTS;
 }
 
 }  // namespace media