moby/integration-cli/docker_cli_userns_test.go
Djordje Lukic 0313544f4a
c8d: Handle userns properly
If the daemon is run with --userns-remap we need to chown the prepared
snapshot

Signed-off-by: Djordje Lukic <djordje.lukic@docker.com>
2023-09-11 16:39:29 +02:00

107 lines
3.9 KiB
Go

//go:build !windows
package main
import (
"fmt"
"os"
"os/exec"
"path"
"path/filepath"
"strconv"
"strings"
"syscall"
"testing"
"github.com/docker/docker/pkg/stringid"
"github.com/docker/docker/testutil"
"gotest.tools/v3/assert"
is "gotest.tools/v3/assert/cmp"
)
// user namespaces test: run daemon with remapped root setting
// 1. validate uid/gid maps are set properly
// 2. verify that files created are owned by remapped root
func (s *DockerDaemonSuite) TestDaemonUserNamespaceRootSetting(c *testing.T) {
testRequires(c, UserNamespaceInKernel)
ctx := testutil.GetContext(c)
s.d.StartWithBusybox(ctx, c, "--userns-remap", "default")
out, err := s.d.Cmd("run", "busybox", "stat", "-c", "%u:%g", "/bin/cat")
assert.Check(c, err)
assert.Assert(c, is.Equal(strings.TrimSpace(out), "0:0"))
tmpDir, err := os.MkdirTemp("", "userns")
assert.NilError(c, err)
defer os.RemoveAll(tmpDir)
// Set a non-existent path
tmpDirNotExists := path.Join(os.TempDir(), "userns"+stringid.GenerateRandomID())
defer os.RemoveAll(tmpDirNotExists)
// we need to find the uid and gid of the remapped root from the daemon's root dir info
uidgid := strings.Split(filepath.Base(s.d.Root), ".")
assert.Equal(c, len(uidgid), 2, fmt.Sprintf("Should have gotten uid/gid strings from root dirname: %s", filepath.Base(s.d.Root)))
uid, err := strconv.Atoi(uidgid[0])
assert.NilError(c, err, "Can't parse uid")
gid, err := strconv.Atoi(uidgid[1])
assert.NilError(c, err, "Can't parse gid")
// writable by the remapped root UID/GID pair
assert.NilError(c, os.Chown(tmpDir, uid, gid))
out, err = s.d.Cmd("run", "-d", "--name", "userns", "-v", tmpDir+":/goofy", "-v", tmpDirNotExists+":/donald", "busybox", "sh", "-c", "touch /goofy/testfile; exec top")
assert.NilError(c, err, "Output: %s", out)
user := s.findUser(c, "userns")
assert.Equal(c, uidgid[0], user)
// check that the created directory is owned by remapped uid:gid
statNotExists, err := os.Stat(tmpDirNotExists)
assert.NilError(c, err)
fi := statNotExists.Sys().(*syscall.Stat_t)
assert.Equal(c, fi.Uid, uint32(uid), "Created directory not owned by remapped root UID")
assert.Equal(c, fi.Gid, uint32(gid), "Created directory not owned by remapped root GID")
pid, err := s.d.Cmd("inspect", "--format={{.State.Pid}}", "userns")
assert.Assert(c, err == nil, "Could not inspect running container: out: %q", pid)
// check the uid and gid maps for the PID to ensure root is remapped
// (cmd = cat /proc/<pid>/uid_map | grep -E '0\s+9999\s+1')
_, err = RunCommandPipelineWithOutput(
exec.Command("cat", "/proc/"+strings.TrimSpace(pid)+"/uid_map"),
exec.Command("grep", "-E", fmt.Sprintf("0[[:space:]]+%d[[:space:]]+", uid)))
assert.NilError(c, err)
_, err = RunCommandPipelineWithOutput(
exec.Command("cat", "/proc/"+strings.TrimSpace(pid)+"/gid_map"),
exec.Command("grep", "-E", fmt.Sprintf("0[[:space:]]+%d[[:space:]]+", gid)))
assert.NilError(c, err)
// check that the touched file is owned by remapped uid:gid
stat, err := os.Stat(filepath.Join(tmpDir, "testfile"))
assert.NilError(c, err)
fi = stat.Sys().(*syscall.Stat_t)
assert.Equal(c, fi.Uid, uint32(uid), "Touched file not owned by remapped root UID")
assert.Equal(c, fi.Gid, uint32(gid), "Touched file not owned by remapped root GID")
// use host usernamespace
out, err = s.d.Cmd("run", "-d", "--name", "userns_skip", "--userns", "host", "busybox", "sh", "-c", "touch /goofy/testfile; exec top")
assert.Assert(c, err == nil, "Output: %s", out)
user = s.findUser(c, "userns_skip")
// userns are skipped, user is root
assert.Equal(c, user, "root")
}
// findUser finds the uid or name of the user of the first process that runs in a container
func (s *DockerDaemonSuite) findUser(c *testing.T, container string) string {
out, err := s.d.Cmd("top", container)
assert.Assert(c, err == nil, "Output: %s", out)
rows := strings.Split(out, "\n")
if len(rows) < 2 {
// No process rows founds
c.FailNow()
}
return strings.Fields(rows[1])[0]
}