cli/context/store: don't treat .DS_Store files as TLS material

cli/context/store/store.go

@@ -192,7 +192,8 @@ func (s *ContextStore) ResetEndpointTLSMaterial(contextName string, endpointName
 }
 
 // ListTLSFiles returns the list of TLS files present for each endpoint in the
-// context.
+// context. Hidden files (such as ".DS_Store"), and the "Thumbs.db" and
+// "desktop.ini" files created by Windows Explorer, are skipped.
 func (s *ContextStore) ListTLSFiles(name string) (map[string]EndpointFiles, error) {
 	return s.tls.listContextData(name)
 }

cli/context/store/store_test.go

@@ -57,6 +57,9 @@ func TestExportImport(t *testing.T) {
 		},
 	})
 	assert.NilError(t, err)
+	// A .DS_Store left by Finder must not end up in the export.
+	err = os.WriteFile(filepath.Join(s.tls.endpointDir("source", "ep1"), ".DS_Store"), []byte("data"), 0o600)
+	assert.NilError(t, err)
 	r := Export("source", s)
 	defer r.Close()
 	err = Import("dest", s, r)
@@ -87,6 +90,8 @@ func TestExportImport(t *testing.T) {
 	destData2, err := s.GetTLSData("dest", "ep1", "file2")
 	assert.NilError(t, err)
 	assert.DeepEqual(t, file2, destData2)
+	_, err = s.GetTLSData("dest", "ep1", ".DS_Store")
+	assert.Check(t, is.ErrorType(err, errdefs.IsNotFound))
 }
 
 func TestRemove(t *testing.T) {

cli/context/store/tlsstore.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"strings"
 
 	"github.com/moby/sys/atomicwriter"
 )
@@ -81,7 +82,7 @@ func (s *tlsStore) listContextData(name string) (map[string]EndpointFiles, error
 			}
 			var files EndpointFiles
 			for _, fs := range fss {
-				if !fs.IsDir() {
+				if !fs.IsDir() && !isIgnoredFile(fs.Name()) {
 					files = append(files, fs.Name())
 				}
 			}
@@ -91,5 +92,15 @@ func (s *tlsStore) listContextData(name string) (map[string]EndpointFiles, error
 	return r, nil
 }
 
+// isIgnoredFile reports whether name should be skipped when listing TLS files.
+// TLS files are never hidden, so all hidden files are skipped: ".DS_Store",
+// "._*" AppleDouble files, and temporary files left by an interrupted write.
+// Windows Explorer's "Thumbs.db" and "desktop.ini" are matched ignoring case.
+func isIgnoredFile(name string) bool {
+	return strings.HasPrefix(name, ".") ||
+		strings.EqualFold(name, "Thumbs.db") ||
+		strings.EqualFold(name, "desktop.ini")
+}
+
 // EndpointFiles is a slice of strings representing file names
 type EndpointFiles []string

cli/context/store/tlsstore_test.go

@@ -1,6 +1,8 @@
 package store
 
 import (
+	"os"
+	"path/filepath"
 	"testing"
 
 	"github.com/containerd/errdefs"
@@ -52,6 +54,11 @@ func TestTlsListAndBatchRemove(t *testing.T) {
 			err := testee.createOrUpdate(contextName, name, file, []byte("data"))
 			assert.NilError(t, err)
 		}
+		// Files like these are created by Finder and Explorer, and must not be listed.
+		for _, file := range []string{".DS_Store", "Thumbs.db"} {
+			err := os.WriteFile(filepath.Join(testee.endpointDir(contextName, name), file), []byte("data"), 0o600)
+			assert.NilError(t, err)
+		}
 	}
 
 	resAll, err := testee.listContextData(contextName)
@@ -70,3 +77,27 @@ func TestTlsListAndBatchRemove(t *testing.T) {
 	assert.NilError(t, err)
 	assert.DeepEqual(t, resEmpty, map[string]EndpointFiles{})
 }
+
+func TestIsIgnoredFile(t *testing.T) {
+	tests := []struct {
+		fileName string
+		ignored  bool
+	}{
+		{fileName: "ca.pem"},
+		{fileName: "cert.pem"},
+		{fileName: "key.pem"},
+		{fileName: "ca.crt"}, // unknown files must still produce a warning
+		{fileName: ".DS_Store", ignored: true},
+		{fileName: "._ca.pem", ignored: true},              // AppleDouble file
+		{fileName: ".tmp-ca.pem1234567890", ignored: true}, // left behind by an interrupted write
+		{fileName: "Thumbs.db", ignored: true},
+		{fileName: "thumbs.db", ignored: true},
+		{fileName: "desktop.ini", ignored: true},
+		{fileName: "Desktop.ini", ignored: true},
+	}
+	for _, tc := range tests {
+		t.Run(tc.fileName, func(t *testing.T) {
+			assert.Equal(t, isIgnoredFile(tc.fileName), tc.ignored)
+		})
+	}
+}