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package copier
import (
"archive/tar"
"bytes"
"encoding/json"
"errors"
"fmt"
"io"
"os"
"path/filepath"
"testing"
"github.com/containers/storage/pkg/mount"
"github.com/containers/storage/pkg/reexec"
"github.com/moby/sys/capability"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
"golang.org/x/sys/unix"
)
func init() {
reexec.Register("get", getWrappedMain)
}
type getWrappedOptions struct {
Root, Directory string
GetOptions GetOptions
Globs []string
DropCaps []capability.Cap
}
func getWrapped(root string, directory string, getOptions GetOptions, globs []string, dropCaps []capability.Cap, bulkWriter io.Writer) error {
options := getWrappedOptions{
Root: root,
Directory: directory,
GetOptions: getOptions,
Globs: globs,
DropCaps: dropCaps,
}
encoded, err := json.Marshal(&options)
if err != nil {
return fmt.Errorf("marshalling options: %w", err)
}
cmd := reexec.Command("get")
cmd.Env = append(cmd.Env, "OPTIONS="+string(encoded))
cmd.Stdout = bulkWriter
stderrBuf := bytes.Buffer{}
cmd.Stderr = &stderrBuf
err = cmd.Run()
if stderrBuf.Len() > 0 {
if err != nil {
return fmt.Errorf("%v: %s", err, stderrBuf.String())
}
return fmt.Errorf("%s", stderrBuf.String())
}
return err
}
func getWrappedMain() {
var options getWrappedOptions
if err := json.Unmarshal([]byte(os.Getenv("OPTIONS")), &options); err != nil {
fmt.Fprintf(os.Stderr, "%v", err)
os.Exit(1)
}
if len(options.DropCaps) > 0 {
caps, err := capability.NewPid2(0)
if err != nil {
fmt.Fprintf(os.Stderr, "%v", err)
os.Exit(1)
}
if err := caps.Load(); err != nil {
fmt.Fprintf(os.Stderr, "%v", err)
os.Exit(1)
}
for _, capType := range []capability.CapType{
capability.AMBIENT,
capability.BOUNDING,
capability.INHERITABLE,
capability.PERMITTED,
capability.EFFECTIVE,
} {
for _, cap := range options.DropCaps {
if caps.Get(capType, cap) {
caps.Unset(capType, cap)
}
}
if err := caps.Apply(capType); err != nil {
fmt.Fprintf(os.Stderr, "error dropping capability %+v: %v", options.DropCaps, err)
os.Exit(1)
}
}
}
if err := Get(options.Root, options.Directory, options.GetOptions, options.Globs, os.Stdout); err != nil {
fmt.Fprintf(os.Stderr, "%v", err)
os.Exit(1)
}
}
func TestGetPermissionErrorNoChroot(t *testing.T) {
couldChroot := canChroot
canChroot = false
testGetPermissionError(t)
canChroot = couldChroot
}
func TestGetPermissionErrorChroot(t *testing.T) {
if uid != 0 {
t.Skipf("chroot() requires root privileges, skipping")
}
couldChroot := canChroot
canChroot = true
testGetPermissionError(t)
canChroot = couldChroot
}
func testGetPermissionError(t *testing.T) {
dropCaps := []capability.Cap{capability.CAP_DAC_OVERRIDE, capability.CAP_DAC_READ_SEARCH}
tmp := t.TempDir()
err := os.Mkdir(filepath.Join(tmp, "unreadable-directory"), 0o000)
require.NoError(t, err, "error creating an unreadable directory")
err = os.Mkdir(filepath.Join(tmp, "readable-directory"), 0o755)
require.NoError(t, err, "error creating a readable directory")
err = os.Mkdir(filepath.Join(tmp, "readable-directory", "unreadable-subdirectory"), 0o000)
require.NoError(t, err, "error creating an unreadable subdirectory")
err = os.WriteFile(filepath.Join(tmp, "unreadable-file"), []byte("hi, i'm a file that you can't read"), 0o000)
require.NoError(t, err, "error creating an unreadable file")
err = os.WriteFile(filepath.Join(tmp, "readable-file"), []byte("hi, i'm also a file, and you can read me"), 0o644)
require.NoError(t, err, "error creating a readable file")
err = os.WriteFile(filepath.Join(tmp, "readable-directory", "unreadable-file"), []byte("hi, i'm also a file that you can't read"), 0o000)
require.NoError(t, err, "error creating an unreadable file in a readable directory")
for _, ignore := range []bool{false, true} {
t.Run(fmt.Sprintf("ignore=%v", ignore), func(t *testing.T) {
var buf bytes.Buffer
err = getWrapped(tmp, tmp, GetOptions{IgnoreUnreadable: ignore}, []string{"."}, dropCaps, &buf)
if ignore {
assert.NoError(t, err, "expected no errors")
tr := tar.NewReader(&buf)
items := 0
_, err := tr.Next()
for err == nil {
items++
_, err = tr.Next()
}
assert.True(t, errors.Is(err, io.EOF), "expected EOF to finish read contents")
assert.Equalf(t, 2, items, "expected two readable items, got %d", items)
} else {
assert.Error(t, err, "expected an error")
assert.Truef(t, errorIsPermission(err), "expected the error (%v) to be a permission error", err)
}
})
}
}
func TestGetNoCrossDevice(t *testing.T) {
if uid != 0 {
t.Skip("test requires root privileges, skipping")
}
tmpdir := t.TempDir()
err := unix.Unshare(unix.CLONE_NEWNS)
require.NoError(t, err, "error creating new mount namespace")
subdir := filepath.Join(tmpdir, "subdir")
err = os.Mkdir(subdir, 0o755)
require.NoErrorf(t, err, "error creating %q", subdir)
err = mount.Mount("tmpfs", subdir, "tmpfs", "rw")
require.NoErrorf(t, err, "error mounting tmpfs at %q", subdir)
defer func() {
err := mount.Unmount(subdir)
assert.NoErrorf(t, err, "error unmounting %q", subdir)
}()
skipped := filepath.Join(subdir, "skipped.txt")
err = os.WriteFile(skipped, []byte("this file should have been skipped\n"), 0o644)
require.NoErrorf(t, err, "error writing file at %q", skipped)
var buf bytes.Buffer
err = Get(tmpdir, tmpdir, GetOptions{NoCrossDevice: true}, []string{"/"}, &buf) // grab contents of tmpdir
require.NoErrorf(t, err, "error reading contents at %q", tmpdir)
tr := tar.NewReader(&buf)
th, err := tr.Next() // should be the "subdir" directory
require.NoError(t, err, "error reading first entry archived")
assert.Equal(t, "subdir", th.Name, `first entry in archive was not named "subdir"`)
th, err = tr.Next()
assert.Error(t, err, "should not have gotten a second entry in archive")
assert.True(t, errors.Is(err, io.EOF), "expected an EOF trying to read a second entry in archive")
if err == nil {
t.Logf("got unexpected entry for %q", th.Name)
}
}
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