vault-23135 - fix modify storage keys ending with .temp causes overwr… (#25395)

* vault-23135 - fix modify storage keys ending with .temp causes overwriting

* CL

* use t.TempDir

changelog/25395.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+storage/file: Fixing spuriously deleting storage keys ending with .temp
+```

sdk/physical/file/file.go

@@ -244,17 +244,21 @@ func (b *FileBackend) PutInternal(ctx context.Context, entry *physical.Entry) er
 
 	// JSON encode the entry and write it
 	fullPath := filepath.Join(path, key)
-	tempPath := fullPath + ".temp"
-	f, err := os.OpenFile(
-		tempPath,
-		os.O_CREATE|os.O_TRUNC|os.O_WRONLY,
-		0o600)
+	f, err := os.CreateTemp(path, key)
 	if err != nil {
 		if f != nil {
 			f.Close()
 		}
 		return err
 	}
+
+	if err = os.Chmod(f.Name(), 0o600); err != nil {
+		if f != nil {
+			f.Close()
+		}
+		return err
+	}
+
 	if f == nil {
 		return errors.New("could not successfully get a file handle")
 	}
@@ -265,7 +269,7 @@ func (b *FileBackend) PutInternal(ctx context.Context, entry *physical.Entry) er
 	})
 	f.Close()
 	if encErr == nil {
-		err = os.Rename(tempPath, fullPath)
+		err = os.Rename(f.Name(), fullPath)
 		if err != nil {
 			return err
 		}
@@ -277,7 +281,7 @@ func (b *FileBackend) PutInternal(ctx context.Context, entry *physical.Entry) er
 	// See if we ended up with a zero-byte file and if so delete it, might be a
 	// case of disk being full but the file info is in metadata that is
 	// reserved.
-	fi, err := os.Stat(tempPath)
+	fi, err := os.Stat(f.Name())
 	if err != nil {
 		return encErr
 	}
@@ -285,7 +289,7 @@ func (b *FileBackend) PutInternal(ctx context.Context, entry *physical.Entry) er
 		return encErr
 	}
 	if fi.Size() == 0 {
-		os.Remove(tempPath)
+		os.Remove(f.Name())
 	}
 	return encErr
 }

sdk/physical/file/file_test.go

@@ -240,3 +240,54 @@ func TestFileBackend(t *testing.T) {
 
 	physical.ExerciseBackend_ListPrefix(t, b)
 }
+
+func TestFileBackendCreateTempKey(t *testing.T) {
+	dir := t.TempDir()
+
+	logger := logging.NewVaultLogger(log.Debug)
+
+	b, err := NewFileBackend(map[string]string{
+		"path": dir,
+	}, logger)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	temp := &physical.Entry{Key: "example.temp", Value: []byte("tempfoo")}
+	err = b.Put(context.Background(), temp)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	nonTemp := &physical.Entry{Key: "example", Value: []byte("foobar")}
+	err = b.Put(context.Background(), nonTemp)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	vals, err := b.List(context.Background(), "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(vals) != 2 || vals[0] == vals[1] {
+		t.Fatalf("bad: %v", vals)
+	}
+	for _, val := range vals {
+		if val != "example.temp" && val != "example" {
+			t.Fatalf("bad val: %v", val)
+		}
+	}
+	out, err := b.Get(context.Background(), "example")
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	if !reflect.DeepEqual(out, nonTemp) {
+		t.Fatalf("bad: %v expected: %v", out, nonTemp)
+	}
+	out, err = b.Get(context.Background(), "example.temp")
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	if !reflect.DeepEqual(out, temp) {
+		t.Fatalf("bad: %v expected: %v", out, temp)
+	}
+}