From e574a6cc1f053a16158bd228cf0ec9c6b255ad09 Mon Sep 17 00:00:00 2001
From: Jakob Unterwurzacher
Date: Sun, 3 Jul 2016 15:35:58 +0200
Subject: nametransform: hide detailed padding error behind the debug flag

unPad16 returns detailed errors including the position of the
incorrect bytes. Kill a possible padding oracle by lumping
everything into a generic error.

The detailed error is only logged if debug is active.
---
 internal/nametransform/names.go | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

(limited to 'internal/nametransform/names.go')

diff --git a/internal/nametransform/names.go b/internal/nametransform/names.go
index 4930488..89ce0db 100644
--- a/internal/nametransform/names.go
+++ b/internal/nametransform/names.go
@@ -10,6 +10,7 @@ import (
 	"github.com/rfjakob/eme"
 
 	"github.com/rfjakob/gocryptfs/internal/cryptocore"
+	"github.com/rfjakob/gocryptfs/internal/tlog"
 )
 
 type NameTransform struct {
@@ -42,7 +43,11 @@ func (n *NameTransform) DecryptName(cipherName string, iv []byte) (string, error
 	bin = eme.Transform(n.cryptoCore.BlockCipher, iv, bin, eme.DirectionDecrypt)
 	bin, err = unPad16(bin)
 	if err != nil {
-		return "", err
+		tlog.Debug.Printf("pad16 error detail: %v", err)
+		// unPad16 returns detailed errors including the position of the
+		// incorrect bytes. Kill the padding oracle by lumping everything into
+		// a generic error.
+		return "", fmt.Errorf("Invalid padding")
 	}
 	plain := string(bin)
 	return plain, err
-- 
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