From 3a2610a141b3afb96050b8dc4f7262939d563133 Mon Sep 17 00:00:00 2001
From: Jakob Unterwurzacher
Date: Wed, 16 Sep 2015 18:43:07 +0200
Subject: symlink encryption: pass ".." and "." through unchanged

This fixes relative symlinks:

$ tar xf linux-4.2.tar.gz
tar: linux-4.2/tools/testing/selftests/powerpc/vphn/vphn.h: Cannot utime: No such file or directory
tar: linux-4.2/tools/testing/selftests/powerpc/vphn/vphn.c: Cannot utime: No such file or directory
tar: linux-4.2/tools/testing/selftests/powerpc/stringloops/memcmp_64.S: Cannot utime: No such file or directory
tar: linux-4.2/tools/testing/selftests/powerpc/primitives/word-at-a-time.h: Cannot utime: No such file or directory
tar: linux-4.2/tools/testing/selftests/powerpc/primitives/asm/asm-compat.h: Cannot utime: No such file or directory
tar: linux-4.2/tools/testing/selftests/powerpc/copyloops/memcpy_power7.S: Cannot utime: No such file or directory
tar: linux-4.2/tools/testing/selftests/powerpc/copyloops/memcpy_64.S: Cannot utime: No such file or directory
tar: linux-4.2/tools/testing/selftests/powerpc/copyloops/copyuser_power7.S: Cannot utime: No such file or directory
tar: linux-4.2/tools/testing/selftests/powerpc/copyloops/copyuser_64.S: Cannot utime: No such file or directory
tar: linux-4.2/arch/powerpc/boot/dts/include/dt-bindings: Cannot utime: No such file or directory
tar: linux-4.2/arch/mips/boot/dts/include/dt-bindings: Cannot utime: No such file or directory
tar: linux-4.2/arch/metag/boot/dts/include/dt-bindings: Cannot utime: No such file or directory
tar: linux-4.2/arch/arm64/boot/dts/include/dt-bindings: Cannot utime: No such file or directory
tar: linux-4.2/arch/arm/boot/dts/include/dt-bindings: Cannot utime: No such file or directory
tar: Exiting with failure status due to previous errors
---
 cryptfs/cryptfs_names.go | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/cryptfs/cryptfs_names.go b/cryptfs/cryptfs_names.go
index c4f2a36..f694fa5 100644
--- a/cryptfs/cryptfs_names.go
+++ b/cryptfs/cryptfs_names.go
@@ -19,6 +19,12 @@ const (
 // DecryptName - decrypt filename
 func (be *CryptFS) decryptName(cipherName string) (string, error) {
 
+	// Make sure relative symlinks still work after encryption
+	// by passing these trough unchanged
+	if cipherName == "." || cipherName == ".." {
+		return cipherName, nil
+	}
+
 	bin, err := base64.URLEncoding.DecodeString(cipherName)
 	if err != nil {
 		return "", err
@@ -44,6 +50,12 @@ func (be *CryptFS) decryptName(cipherName string) (string, error) {
 // EncryptName - encrypt filename
 func (be *CryptFS) encryptName(plainName string) string {
 
+	// Make sure relative symlinks still work after encryption
+	// by passing these trough unchanged
+	if plainName == "." || plainName == ".." {
+		return plainName
+	}
+
 	bin := []byte(plainName)
 	bin = be.pad16(bin)
 
-- 
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