mkvmuxer: Reject frames if invalid track number is passed.

Reject frames if an invalid track number is passed. Also change sample_muxer
to reject files which have Block elements with invalid track numbers.

Fixes Issue #659: https://code.google.com/p/webm/issues/detail?id=659

Change-Id: Ie6cf39a409b68bb4d2261f308409ee0c36d5dd8e

mkvmuxer.cpp

@@ -2276,6 +2276,10 @@ bool Segment::AddFrame(const uint8* frame, uint64 length, uint64 track_number,
   if (timestamp < last_timestamp_)
     return false;
 
+  // Check if the track number is valid.
+  if (!tracks_.GetTrackByNumber(track_number))
+    return false;
+
   // If the segment has a video track hold onto audio frames to make sure the
   // audio that is associated with the start time of a video key-frame is
   // muxed into the same cluster.
@@ -2335,6 +2339,10 @@ bool Segment::AddFrameWithAdditional(const uint8* frame, uint64 length,
   if (timestamp < last_timestamp_)
     return false;
 
+  // Check if the track number is valid.
+  if (!tracks_.GetTrackByNumber(track_number))
+    return false;
+
   // If the segment has a video track hold onto audio frames to make sure the
   // audio that is associated with the start time of a video key-frame is
   // muxed into the same cluster.
@@ -2395,6 +2403,10 @@ bool Segment::AddFrameWithDiscardPadding(const uint8* frame, uint64 length,
   if (timestamp < last_timestamp_)
     return false;
 
+  // Check if the track_number is valid.
+  if (!tracks_.GetTrackByNumber(track_number))
+    return false;
+
   // If the segment has a video track hold onto audio frames to make sure the
   // audio that is associated with the start time of a video key-frame is
   // muxed into the same cluster.
@@ -2455,6 +2467,10 @@ bool Segment::AddMetadata(const uint8* frame, uint64 length,
   if (timestamp_ns < last_timestamp_)
     return false;
 
+  // Check if the track number is valid.
+  if (!tracks_.GetTrackByNumber(track_number))
+    return false;
+
   if (!DoNewClusterProcessing(track_number, timestamp_ns, true))
     return false;
 
@@ -2481,6 +2497,9 @@ bool Segment::AddMetadata(const uint8* frame, uint64 length,
 }
 
 bool Segment::AddGenericFrame(const Frame* frame) {
+  if (!tracks_.GetTrackByNumber(frame->track_number())) {
+    return false;
+  }
   last_block_duration_ = frame->duration();
   if (!tracks_.TrackIsAudio(frame->track_number()) &&
       !tracks_.TrackIsVideo(frame->track_number()) && frame->duration() > 0) {

sample_muxer.cpp

@@ -457,6 +457,14 @@ int main(int argc, char* argv[]) {
       const long long trackNum = block->GetTrackNumber();
       const mkvparser::Track* const parser_track =
           parser_tracks->GetTrackByNumber(static_cast<unsigned long>(trackNum));
+
+      // When |parser_track| is NULL, it means that the track number in the
+      // Block is invalid (i.e.) the was no TrackEntry corresponding to the
+      // track number. So we reject the file.
+      if (!parser_track) {
+        return EXIT_FAILURE;
+      }
+
       const long long track_type = parser_track->GetType();
       const long long time_ns = block->GetTime(cluster);