fusefrontend: do not encrypt ACLs

Pass through system.posix_acl_access and system.posix_acl_default
unencrypted to fix "cp -a" problems.

"cp -a" uses "setxattr" even to set normal permissions, see
https://www.spinics.net/lists/linux-nfs/msg63986.html .

Fixes https://github.com/rfjakob/gocryptfs/issues/543

1 files changed, 202 insertions, 0 deletions

diff --git a/tests/defaults/acl_test.go b/tests/defaults/acl_test.go
new file mode 100644
index 0000000..b3826e8
--- /dev/null
+++ b/tests/defaults/acl_test.go
@@ -0,0 +1,202 @@
+package defaults
+
+import (
+	"io/ioutil"
+	"math/rand"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"syscall"
+	"testing"
+	"time"
+
+	"golang.org/x/sys/unix"
+
+	"github.com/pkg/xattr"
+
+	"github.com/rfjakob/gocryptfs/tests/test_helpers"
+)
+
+// https://github.com/rfjakob/gocryptfs/issues/543
+func TestCpA(t *testing.T) {
+	fn1 := filepath.Join(test_helpers.TmpDir, t.Name())
+	fn2 := filepath.Join(test_helpers.DefaultPlainDir, t.Name())
+
+	rand.Seed(int64(time.Now().Nanosecond()))
+
+	{
+		// Need unrestricted umask
+		old := syscall.Umask(000)
+		defer syscall.Umask(old)
+	}
+
+	for i := 0; i < 10; i++ {
+		// Random permissions (except owner read, which cp needs)
+		var modeWant os.FileMode = os.FileMode(rand.Int31n(0777+1) | 0400)
+
+		// Create file outside mount
+		err := ioutil.WriteFile(fn1, nil, modeWant)
+		if err != nil {
+			t.Fatal(err)
+		}
+		// Verify perms (umask problems?)
+		fi, err := os.Stat(fn1)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if fi.Mode() != modeWant {
+			t.Errorf("ioutil.WriteFile created wrong permissions: want %o have %o", modeWant, fi.Mode())
+		}
+
+		// "cp -a" from outside to inside mount
+		c := exec.Command("cp", "-a", fn1, fn2)
+		c.Stderr = os.Stderr
+		c.Stdout = os.Stdout
+		err = c.Run()
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		// Check perms
+		fi, err = os.Stat(fn2)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if fi.Mode() != modeWant {
+			t.Errorf("cp -a did not preserve permissions: want %o have %o", modeWant, fi.Mode())
+		}
+
+		syscall.Unlink(fn1)
+		syscall.Unlink(fn2)
+	}
+}
+
+func getfacl(fn string) (string, error) {
+	c := exec.Command("getfacl", "-c", "--", fn)
+	out, err := c.Output()
+	return string(out), err
+}
+
+// https://github.com/rfjakob/gocryptfs/issues/543
+func TestAcl543(t *testing.T) {
+	fn1 := test_helpers.TmpDir + "/TestAcl543"
+	fn2 := test_helpers.DefaultPlainDir + "/TestAcl543"
+
+	var c *exec.Cmd
+
+	var modeWant os.FileMode = 0777
+
+	{
+		// Need unrestricted umask
+		old := syscall.Umask(000)
+		defer syscall.Umask(old)
+	}
+
+	// Set acl on file outside gocryptfs mount
+	err := ioutil.WriteFile(fn1, nil, modeWant)
+	if err != nil {
+		t.Fatal(err)
+	}
+	c = exec.Command("setfacl", "-m", "u:daemon:rwx", fn1)
+	c.Stderr = os.Stderr
+	c.Stdout = os.Stdout
+	err = c.Run()
+	if err != nil {
+		t.Skip(err)
+	}
+	aclWant, err := getfacl(fn1)
+	if err != nil {
+		t.Fatal(err)
+	}
+	fi, err := os.Stat(fn1)
+	if fi.Mode() != modeWant {
+		t.Fatalf("mode changed from %o to %o", modeWant, fi.Mode())
+	}
+
+	// Set acl on file inside gocryptfs mount
+	err = ioutil.WriteFile(fn2, nil, modeWant)
+	if err != nil {
+		t.Fatal(err)
+	}
+	c = exec.Command("setfacl", "-m", "u:daemon:rwx", fn2)
+	c.Stderr = os.Stderr
+	c.Stdout = os.Stdout
+	err = c.Run()
+	if err != nil {
+		t.Fatal(err)
+	}
+	aclHave1, err := getfacl(fn1)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if aclHave1 != aclWant {
+		t.Error(aclHave1)
+	}
+	os.Remove(fn2)
+
+	// "cp -a" from outside to inside mount
+	c = exec.Command("cp", "-a", fn1, fn2)
+	c.Stderr = os.Stderr
+	c.Stdout = os.Stdout
+	err = c.Run()
+	if err != nil {
+		t.Fatal(err)
+	}
+	fi, err = os.Stat(fn2)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if fi.Mode() != modeWant {
+		t.Errorf("cp -a did not preserve permissions: want %o have %o", modeWant, fi.Mode())
+	}
+	aclHave2, err := getfacl(fn2)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if aclHave2 != aclWant {
+		t.Errorf("cp -a did not preserve acl: %q", aclHave1)
+	}
+}
+
+// Check that we handle zero-sized and undersized buffers correctly
+func TestXattrOverflow(t *testing.T) {
+	fn := filepath.Join(test_helpers.DefaultPlainDir, t.Name())
+	ioutil.WriteFile(fn, nil, 0600)
+
+	attr := "user.foo123"
+	val := []byte("12341234")
+	err := xattr.LSet(fn, attr, val)
+	if err != nil {
+		t.Skip(err)
+	}
+
+	// Getxattr
+	sz, err := unix.Lgetxattr(fn, attr, nil)
+	if err != nil {
+		t.Error(err)
+	}
+	if sz != len(val) {
+		t.Errorf("wrong sz: want %d have %d", len(val), sz)
+	}
+	sz, err = unix.Lgetxattr(fn, attr, make([]byte, 1))
+	if err != syscall.ERANGE {
+		t.Error(err)
+	}
+
+	// Listxattr
+	szWant, err := unix.Llistxattr(fn, make([]byte, 64*1024))
+	if err != nil {
+		t.Fatal(err)
+	}
+	sz, err = unix.Llistxattr(fn, nil)
+	if err != nil {
+		t.Error(err)
+	}
+	if sz != szWant {
+		t.Errorf("wrong sz: want %d have %d", szWant, sz)
+	}
+	sz, err = unix.Llistxattr(fn, make([]byte, 1))
+	if err != syscall.ERANGE {
+		t.Error(err)
+	}
+}