Add EME filename encryption & enable it by default

1 files changed, 63 insertions, 0 deletions

diff --git a/cryptfs/names_noiv.go b/cryptfs/names_noiv.go
new file mode 100644
index 0000000..7eed4b8
--- /dev/null
+++ b/cryptfs/names_noiv.go
@@ -0,0 +1,63 @@
+package cryptfs
+
+import (
+	"strings"
+)
+
+const (
+	OpEncrypt = iota
+	OpDecrypt
+)
+
+// DecryptPathNoIV - decrypt path using CBC without any IV.
+// This function is deprecated by the the more secure DirIV variant and only retained
+// for compatability with old filesystems.
+func (be *CryptFS) DecryptPathNoIV(cipherPath string) (plainPath string, err error) {
+	plainPath, err = be.translatePathNoIV(cipherPath, OpDecrypt)
+	return plainPath, err
+}
+
+// EncryptPathNoIV - decrypt path using CBC without any IV.
+// This function is deprecated by the the more secure DirIV variant and only retained
+// for compatability with old filesystems.
+func (be *CryptFS) EncryptPathNoIV(plainPath string) (cipherPath string) {
+	cipherPath, _ = be.translatePathNoIV(plainPath, OpEncrypt)
+	return cipherPath
+}
+
+// translatePathZeroIV - encrypt or decrypt path using CBC with an all-zero IV.
+// Just splits the string on "/" and hands the parts to encryptName() / decryptName()
+func (be *CryptFS) translatePathNoIV(path string, op int) (string, error) {
+	var err error
+
+	// Empty string means root directory
+	if path == "" {
+		return path, err
+	}
+
+	zeroIV := make([]byte, DIRIV_LEN)
+
+	// Run operation on each path component
+	var translatedParts []string
+	parts := strings.Split(path, "/")
+	for _, part := range parts {
+		if part == "" {
+			// This happens on "/foo/bar/" on the front and on the end.
+			// Don't panic.
+			translatedParts = append(translatedParts, "")
+			continue
+		}
+		var newPart string
+		if op == OpEncrypt {
+			newPart = be.encryptName(part, zeroIV, false)
+		} else {
+			newPart, err = be.decryptName(part, zeroIV, false)
+			if err != nil {
+				return "", err
+			}
+		}
+		translatedParts = append(translatedParts, newPart)
+	}
+
+	return strings.Join(translatedParts, "/"), err
+}