Set error on unrecognized top-level BMFF boxes.

media/mp4/box_reader.cc

Index: media/mp4/box_reader.cc
diff --git a/media/mp4/box_reader.cc b/media/mp4/box_reader.cc
index 8892a43991cbd1e9b976134c1ca00f640baaca83..1d86e7bdf01a54c99e42edbe670fce2efe6a35f5 100644
--- a/media/mp4/box_reader.cc
+++ b/media/mp4/box_reader.cc
@@ -10,6 +10,7 @@
 #include <set>
 
 #include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
 #include "media/mp4/box_definitions.h"
 #include "media/mp4/rcheck.h"
 
@@ -95,14 +96,24 @@ BoxReader::~BoxReader() {
   }
 }
 
+// static
 BoxReader* BoxReader::ReadTopLevelBox(const uint8* buf,
                                       const int buf_size,
                                       bool* err) {
-  BoxReader* reader = new BoxReader(buf, buf_size);
-  if (reader->ReadHeader(err) && reader->size() <= buf_size) {
-    return reader;
+  scoped_ptr<BoxReader> reader(new BoxReader(buf, buf_size));
+  if (!reader->ReadHeader(err))
+    return NULL;
+
+  if (!IsValidTopLevelBox(reader->type())) {
+    LOG(WARNING) << "Unrecognized top-level box type 0x"
+                 << std::hex << reader->type();

[acolwell GONE FROM CHROMIUM, 2012/08/02 20:38:18]

Any reason not to use FourCCToString() here like you do in other places?

[strobe_, 2012/08/02 21:27:50]

In the expected case of misregistration, the box type will often contain
unprintable characters. Comment added.

[acolwell GONE FROM CHROMIUM, 2012/08/02 21:40:25]

Ok. Makes sense.

+    *err = true;
+    return NULL;
   }
-  delete reader;
+
+  if (reader->size() <= buf_size)
+    return reader.release();
+
   return NULL;
 }
 
@@ -114,11 +125,33 @@ bool BoxReader::StartTopLevelBox(const uint8* buf,
                                  bool* err) {
   BoxReader reader(buf, buf_size);
   if (!reader.ReadHeader(err)) return false;
+  if (!IsValidTopLevelBox(reader.type())) {
+    *err = true;
+    return false;
+  }
   *type = reader.type();
   *box_size = reader.size();
   return true;
 }
 
+// static
+bool BoxReader::IsValidTopLevelBox(const FourCC& type) {
+  return (type == FOURCC_FTYP ||

[acolwell GONE FROM CHROMIUM, 2012/08/02 20:38:18]

nit: WDYT about using a switch() here w/ a return true and putting the logging
statement you have above in default: ? That way you'll log for ReadTopLevelBox()
& StartTopLevelBox().

[strobe_, 2012/08/02 21:27:50]

Done.

+          type == FOURCC_PDIN ||
+          type == FOURCC_MOOV ||
+          type == FOURCC_MOOF ||
+          type == FOURCC_MFRA ||
+          type == FOURCC_MDAT ||
+          type == FOURCC_FREE ||
+          type == FOURCC_SKIP ||
+          type == FOURCC_META ||
+          type == FOURCC_MECO ||
+          type == FOURCC_STYP ||
+          type == FOURCC_SIDX ||
+          type == FOURCC_SSIX ||
+          type == FOURCC_PRFT);
+}
+
 bool BoxReader::ScanChildren() {
   DCHECK(!scanned_);
   scanned_ = true;