From 5e53dcfd7c12e45d4142016d0b9b286f9aa83d56 Mon Sep 17 00:00:00 2001
From: Mauri de Souza Meneguzzo <mauri870@gmail.com>
Date: Tue, 8 Aug 2023 21:16:49 -0300
Subject: [PATCH] archive/zip: reject non-regular files in AddFS

When a filesystem with non-regular files is used
the resulting files inside the zip archive are empty.

In this case we can be explicit and return an error.

Fixes #61875
---
 src/archive/zip/writer.go      |  3 +++
 src/archive/zip/writer_test.go | 23 +++++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/src/archive/zip/writer.go b/src/archive/zip/writer.go
index 3da5ad612b..5dd6096fc5 100644
--- a/src/archive/zip/writer.go
+++ b/src/archive/zip/writer.go
@@ -504,6 +504,9 @@ func (w *Writer) AddFS(fsys fs.FS) error {
 		if err != nil {
 			return err
 		}
+		if !info.Mode().IsRegular() {
+			return errors.New("zip: cannot add non-regular file")
+		}
 		h, err := FileInfoHeader(info)
 		if err != nil {
 			return err
diff --git a/src/archive/zip/writer_test.go b/src/archive/zip/writer_test.go
index 5250bc112e..bd33a07c3c 100644
--- a/src/archive/zip/writer_test.go
+++ b/src/archive/zip/writer_test.go
@@ -648,3 +648,26 @@ func TestWriterAddFS(t *testing.T) {
 		testReadFile(t, r.File[i], &wt)
 	}
 }
+
+func TestIssue61875(t *testing.T) {
+	buf := new(bytes.Buffer)
+	w := NewWriter(buf)
+	tests := []WriteTest{
+		{
+			Name:   "symlink",
+			Data:   []byte("../link/target"),
+			Method: Deflate,
+			Mode:   0755 | fs.ModeSymlink,
+		},
+		{
+			Name:   "device",
+			Data:   []byte(""),
+			Method: Deflate,
+			Mode:   0755 | fs.ModeDevice,
+		},
+	}
+	err := w.AddFS(writeTestsToFS(tests))
+	if err == nil {
+		t.Errorf("expected error, got nil")
+	}
+}