nametransform: add longNameMax parameter

Determines when to start hashing long names instead
of hardcoded 255. Will be used to alleviate "name too long"
issues some users see on cloud storage.

https://github.com/rfjakob/gocryptfs/issues/499

1 files changed, 41 insertions, 0 deletions

diff --git a/internal/nametransform/longnames_test.go b/internal/nametransform/longnames_test.go
index 4210492..7a4e915 100644
--- a/internal/nametransform/longnames_test.go
+++ b/internal/nametransform/longnames_test.go
@@ -1,7 +1,11 @@
 package nametransform
 
 import (
+	"strings"
 	"testing"
+
+	"github.com/rfjakob/gocryptfs/v2/internal/contentenc"
+	"github.com/rfjakob/gocryptfs/v2/internal/cryptocore"
 )
 
 func TestIsLongName(t *testing.T) {
@@ -28,3 +32,40 @@ func TestRemoveLongNameSuffix(t *testing.T) {
 		t.Error(".name suffix not removed")
 	}
 }
+
+func newLognamesTestInstance(longNameMax uint8) *NameTransform {
+	key := make([]byte, cryptocore.KeyLen)
+	cCore := cryptocore.New(key, cryptocore.BackendGoGCM, contentenc.DefaultIVBits, true)
+	return New(cCore.EMECipher, true, longNameMax, true, nil, false)
+}
+
+func TestLongNameMax(t *testing.T) {
+	iv := make([]byte, 16)
+	for max := 0; max <= NameMax; max++ {
+		n := newLognamesTestInstance(uint8(max))
+		if max == 0 {
+			// effective value is 255
+			max = NameMax
+		}
+		for l := 0; l <= NameMax+10; l++ {
+			name := strings.Repeat("x", l)
+			out, err := n.EncryptAndHashName(name, iv)
+			if l == 0 || l > NameMax {
+				if err == nil {
+					t.Errorf("should have rejected a name of length %d, but did not", l)
+				}
+				continue
+			}
+			cName, _ := n.EncryptName(name, iv)
+			rawLen := len(cName)
+			want := LongNameNone
+			if rawLen > max {
+				want = LongNameContent
+			}
+			have := NameType(out)
+			if have != want {
+				t.Errorf("l=%d max=%d: wanted %v, got %v\nname=%q\nout=%q", l, max, want, have, name, out)
+			}
+		}
+	}
+}