Properly verify that input data is just 'pssh' boxes

media/cdm/cenc_utils.cc

 // Copyright 2015 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 "media/cdm/cenc_utils.h"
 
 #include "base/stl_util.h"
 #include "media/formats/mp4/box_definitions.h"
 #include "media/formats/mp4/box_reader.h"
 
@@ skipping 12 matching lines @@
 
 // Returns true if |input| contains only 1 or more valid 'pssh' boxes, false
 // otherwise. |pssh_boxes| is updated as the set of parsed 'pssh' boxes.
 // Note: All boxes in |input| must be 'pssh' boxes. However, if they can't be
 //       properly parsed (e.g. unsupported version), then they will be skipped.
 static bool ReadAllPsshBoxes(
     const std::vector<uint8_t>& input,
     std::vector<mp4::FullProtectionSystemSpecificHeader>* pssh_boxes) {
   DCHECK(!input.empty());
 
-  // Verify that |input| contains only 'pssh' boxes. ReadAllChildren() is
-  // templated, so it checks that each box in |input| matches the box type of
-  // the parameter (in this case mp4::ProtectionSystemSpecificHeader is a
-  // 'pssh' box). mp4::ProtectionSystemSpecificHeader doesn't validate the
-  // 'pssh' contents, so this simply verifies that |input| only contains
-  // 'pssh' boxes and nothing else.
+  // Verify that |input| contains only 'pssh' boxes.
+  // ReadAllChildrenAndCheckFourCC() is templated, so it checks that each
+  // box in |input| matches the box type of the parameter (in this case
+  // mp4::ProtectionSystemSpecificHeader is a 'pssh' box).
+  // mp4::ProtectionSystemSpecificHeader doesn't validate the 'pssh' contents,
+  // so this simply verifies that |input| only contains 'pssh' boxes and
+  // nothing else.
   scoped_ptr<mp4::BoxReader> input_reader(
       mp4::BoxReader::ReadConcatentatedBoxes(
           vector_as_array(&input), input.size()));
   std::vector<mp4::ProtectionSystemSpecificHeader> raw_pssh_boxes;
-  if (!input_reader->ReadAllChildren(&raw_pssh_boxes))
+  if (!input_reader->ReadAllChildrenAndCheckFourCC(&raw_pssh_boxes))
     return false;
 
   // Now that we have |input| parsed into |raw_pssh_boxes|, reparse each one
   // into a mp4::FullProtectionSystemSpecificHeader, which extracts all the
   // relevant fields from the box. Since there may be unparseable 'pssh' boxes
   // (due to unsupported version, for example), this is done one by one,
   // ignoring any boxes that can't be parsed.
   for (const auto& raw_pssh_box : raw_pssh_boxes) {
     scoped_ptr<mp4::BoxReader> raw_pssh_reader(
         mp4::BoxReader::ReadConcatentatedBoxes(
             vector_as_array(&raw_pssh_box.raw_box),
             raw_pssh_box.raw_box.size()));
     // ReadAllChildren() appends any successfully parsed box onto it's
     // parameter, so |pssh_boxes| will contain the collection of successfully
     // parsed 'pssh' boxes. If an error occurs, try the next box.
-    if (!raw_pssh_reader->ReadAllChildren(pssh_boxes))
+    if (!raw_pssh_reader->ReadAllChildrenAndCheckFourCC(pssh_boxes))
       continue;
   }
 
   // Must have successfully parsed at least one 'pssh' box.
   return pssh_boxes->size() > 0;
 }
 
 bool ValidatePsshInput(const std::vector<uint8_t>& input) {
   // No 'pssh' boxes is considered valid.
   if (input.empty())
@@ skipping 47 matching lines @@
       pssh_data->assign(child.data.begin(), child.data.end());
       return true;
     }
   }
 
   // No matching 'pssh' box found.
   return false;
 }
 
 }  // namespace media