From 021b23a5e773c217db10b91796d87fc544cc06dd Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Tue, 27 Sep 2016 02:13:56 +0900
Subject: [PATCH] audio/wav: Bug fix: return an error when offset is before the
 start of the data

---
 audio/wav/decode.go | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/audio/wav/decode.go b/audio/wav/decode.go
index 33a7b5c70..e1cd39fc1 100644
--- a/audio/wav/decode.go
+++ b/audio/wav/decode.go
@@ -50,8 +50,14 @@ func (s *Stream) Seek(offset int64, whence int) (int64, error) {
 		offset += s.headerSize
 	}
 	n, err := s.src.Seek(offset, whence)
+	if err != nil {
+		return 0, err
+	}
+	if n-s.headerSize < 0 {
+		return 0, fmt.Errorf("wav: invalid offset")
+	}
 	s.remaining = s.dataSize - (n - s.headerSize)
-	return n, err
+	return n, nil
 }
 
 // Read is implementation of io.Closer's Close.