From ad73a0ea8958ed6cb15513798762be65e5c29568 Mon Sep 17 00:00:00 2001
From: Matt Joiner <anacrolix@gmail.com>
Date: Sun, 23 Aug 2015 17:47:01 +1000
Subject: [PATCH] bencode: Trailing bytes on Unmarshal is an error

---
 bencode/api.go | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/bencode/api.go b/bencode/api.go
index b4ddcec9..a17d1820 100644
--- a/bencode/api.go
+++ b/bencode/api.go
@@ -3,6 +3,7 @@ package bencode
 import (
 	"bufio"
 	"bytes"
+	"errors"
 	"fmt"
 	"io"
 	"reflect"
@@ -127,9 +128,23 @@ func Marshal(v interface{}) ([]byte, error) {
 
 // Unmarshal the bencode value in the 'data' to a value pointed by the 'v'
 // pointer, return a non-nil error if any.
-func Unmarshal(data []byte, v interface{}) error {
+func Unmarshal(data []byte, v interface{}) (err error) {
 	e := decoder{Reader: bufio.NewReader(bytes.NewBuffer(data))}
-	return e.decode(v)
+	err = e.decode(v)
+	if err != nil {
+		return
+	}
+	_, err = e.Reader.ReadByte()
+	if err == io.EOF {
+		return nil
+	}
+	if err == nil {
+		err = &SyntaxError{
+			Offset: e.offset,
+			What:   errors.New("trailing bytes"),
+		}
+	}
+	return
 }
 
 //----------------------------------------------------------------------------
-- 
2.48.1