From fbccb160438aba6f1e16b26a982122c726afee1a Mon Sep 17 00:00:00 2001
From: Jakob Unterwurzacher
Date: Fri, 20 Aug 2021 17:06:18 +0200
Subject: -deterministic-names: implement for reverse mode, too

---
 internal/fusefrontend_reverse/rpath.go | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

(limited to 'internal/fusefrontend_reverse/rpath.go')

diff --git a/internal/fusefrontend_reverse/rpath.go b/internal/fusefrontend_reverse/rpath.go
index 199473b..7ebedd7 100644
--- a/internal/fusefrontend_reverse/rpath.go
+++ b/internal/fusefrontend_reverse/rpath.go
@@ -2,6 +2,7 @@ package fusefrontend_reverse
 
 import (
 	"encoding/base64"
+	"log"
 	"path/filepath"
 	"strings"
 	"syscall"
@@ -72,7 +73,7 @@ func (rn *RootNode) decryptPath(cPath string) (string, error) {
 		// Start at the top and recurse
 		currentCipherDir := filepath.Join(parts[:i]...)
 		currentPlainDir := filepath.Join(transformedParts[:i]...)
-		dirIV := pathiv.Derive(currentCipherDir, pathiv.PurposeDirIV)
+		dirIV := rn.deriveDirIV(currentCipherDir)
 		transformedPart, err := rn.rDecryptName(parts[i], dirIV, currentPlainDir)
 		if err != nil {
 			return "", err
@@ -83,6 +84,17 @@ func (rn *RootNode) decryptPath(cPath string) (string, error) {
 	return pRelPath, nil
 }
 
+// deriveDirIV wraps pathiv.Derive but takes DeterministicNames into account.
+func (rn *RootNode) deriveDirIV(cPath string) []byte {
+	if rn.args.PlaintextNames {
+		log.Panic("BUG: deriveDirIV called but PlaintextNames is set")
+	}
+	if rn.args.DeterministicNames {
+		return make([]byte, nametransform.DirIVLen)
+	}
+	return pathiv.Derive(cPath, pathiv.PurposeDirIV)
+}
+
 // openBackingDir receives an already decrypted relative path
 // "pRelPath", opens the directory that contains the target file/dir
 // and returns the fd to the directory and the decrypted name of the
-- 
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