archive/zip: error on ReadDir if there are invalid file names

Fixes #50179

Change-Id: I616a6d1279d025e345d2daa6d44b687c8a2d09e1
Reviewed-on: https://go-review.googlesource.com/c/go/+/656495
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>

src/archive/zip/reader.go

@@ -8,6 +8,7 @@ import (
 	"bufio"
 	"encoding/binary"
 	"errors"
+	"fmt"
 	"hash"
 	"hash/crc32"
 	"internal/godebug"
@@ -988,6 +989,12 @@ func (d *openDir) ReadDir(count int) ([]fs.DirEntry, error) {
 		s, err := d.files[d.offset+i].stat()
 		if err != nil {
 			return nil, err
+		} else if s.Name() == "." || !fs.ValidPath(s.Name()) {
+			return nil, &fs.PathError{
+				Op:   "readdir",
+				Path: d.e.name,
+				Err:  fmt.Errorf("invalid file name: %v", d.files[d.offset+i].name),
+			}
 		}
 		list[i] = s
 	}

src/archive/zip/reader_test.go

@@ -8,6 +8,7 @@ import (
 	"bytes"
 	"encoding/binary"
 	"encoding/hex"
+	"errors"
 	"internal/obscuretestdata"
 	"io"
 	"io/fs"
@@ -1281,6 +1282,49 @@ func TestFSWalk(t *testing.T) {
 	}
 }
 
+func TestFSWalkBadFile(t *testing.T) {
+	t.Parallel()
+
+	var buf bytes.Buffer
+	zw := NewWriter(&buf)
+	hdr := &FileHeader{Name: "."}
+	hdr.SetMode(fs.ModeDir | 0o755)
+	w, err := zw.CreateHeader(hdr)
+	if err != nil {
+		t.Fatalf("create zip header: %v", err)
+	}
+	_, err = w.Write([]byte("some data"))
+	if err != nil {
+		t.Fatalf("write zip contents: %v", err)
+
+	}
+	err = zw.Close()
+	if err != nil {
+		t.Fatalf("close zip writer: %v", err)
+
+	}
+
+	zr, err := NewReader(bytes.NewReader(buf.Bytes()), int64(buf.Len()))
+	if err != nil {
+		t.Fatalf("create zip reader: %v", err)
+
+	}
+	var count int
+	var errRepeat = errors.New("repeated call to path")
+	err = fs.WalkDir(zr, ".", func(p string, d fs.DirEntry, err error) error {
+		count++
+		if count > 2 { // once for directory read, once for the error
+			return errRepeat
+		}
+		return err
+	})
+	if err == nil {
+		t.Fatalf("expected error from invalid file name")
+	} else if errors.Is(err, errRepeat) {
+		t.Fatal(err)
+	}
+}
+
 func TestFSModTime(t *testing.T) {
 	t.Parallel()
 	z, err := OpenReader("testdata/subdir.zip")