125 lines
3.5 KiB
Go
125 lines
3.5 KiB
Go
// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build linux
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package syscall_test
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import (
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"io/ioutil"
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"os"
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"os/exec"
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"strings"
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"syscall"
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"testing"
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)
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// Check if we are in a chroot by checking if the inode of / is
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// different from 2 (there is no better test available to non-root on
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// linux).
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func isChrooted(t *testing.T) bool {
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root, err := os.Stat("/")
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if err != nil {
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t.Fatalf("cannot stat /: %v", err)
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}
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return root.Sys().(*syscall.Stat_t).Ino != 2
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}
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func whoamiCmd(t *testing.T, uid, gid int, setgroups bool) *exec.Cmd {
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if _, err := os.Stat("/proc/self/ns/user"); err != nil {
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if os.IsNotExist(err) {
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t.Skip("kernel doesn't support user namespaces")
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}
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t.Fatalf("Failed to stat /proc/self/ns/user: %v", err)
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}
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if isChrooted(t) {
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// create_user_ns in the kernel (see
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// https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/kernel/user_namespace.c)
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// forbids the creation of user namespaces when chrooted.
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t.Skip("cannot create user namespaces when chrooted")
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}
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// On some systems, there is a sysctl setting.
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if os.Getuid() != 0 {
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data, errRead := ioutil.ReadFile("/proc/sys/kernel/unprivileged_userns_clone")
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if errRead == nil && data[0] == '0' {
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t.Skip("kernel prohibits user namespace in unprivileged process")
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}
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}
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// When running under the Go continuous build, skip tests for
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// now when under Kubernetes. (where things are root but not quite)
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// Both of these are our own environment variables.
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// See Issue 12815.
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if os.Getenv("GO_BUILDER_NAME") != "" && os.Getenv("IN_KUBERNETES") == "1" {
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t.Skip("skipping test on Kubernetes-based builders; see Issue 12815")
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}
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cmd := exec.Command("whoami")
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cmd.SysProcAttr = &syscall.SysProcAttr{
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Cloneflags: syscall.CLONE_NEWUSER,
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UidMappings: []syscall.SysProcIDMap{
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{ContainerID: 0, HostID: uid, Size: 1},
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},
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GidMappings: []syscall.SysProcIDMap{
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{ContainerID: 0, HostID: gid, Size: 1},
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},
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GidMappingsEnableSetgroups: setgroups,
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}
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return cmd
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}
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func testNEWUSERRemap(t *testing.T, uid, gid int, setgroups bool) {
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cmd := whoamiCmd(t, uid, gid, setgroups)
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out, err := cmd.CombinedOutput()
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if err != nil {
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t.Fatalf("Cmd failed with err %v, output: %s", err, out)
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}
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sout := strings.TrimSpace(string(out))
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want := "root"
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if sout != want {
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t.Fatalf("whoami = %q; want %q", out, want)
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}
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}
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func TestCloneNEWUSERAndRemapRootDisableSetgroups(t *testing.T) {
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if os.Getuid() != 0 {
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t.Skip("skipping root only test")
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}
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testNEWUSERRemap(t, 0, 0, false)
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}
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func TestCloneNEWUSERAndRemapRootEnableSetgroups(t *testing.T) {
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if os.Getuid() != 0 {
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t.Skip("skipping root only test")
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}
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testNEWUSERRemap(t, 0, 0, false)
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}
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func TestCloneNEWUSERAndRemapNoRootDisableSetgroups(t *testing.T) {
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if os.Getuid() == 0 {
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t.Skip("skipping unprivileged user only test")
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}
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testNEWUSERRemap(t, os.Getuid(), os.Getgid(), false)
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}
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func TestCloneNEWUSERAndRemapNoRootSetgroupsEnableSetgroups(t *testing.T) {
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if os.Getuid() == 0 {
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t.Skip("skipping unprivileged user only test")
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}
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cmd := whoamiCmd(t, os.Getuid(), os.Getgid(), true)
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err := cmd.Run()
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if err == nil {
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t.Skip("probably old kernel without security fix")
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}
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if !os.IsPermission(err) {
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t.Fatalf("Unprivileged gid_map rewriting with GidMappingsEnableSetgroups must fail")
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}
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}
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func TestEmptyCredGroupsDisableSetgroups(t *testing.T) {
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cmd := whoamiCmd(t, os.Getuid(), os.Getgid(), false)
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cmd.SysProcAttr.Credential = &syscall.Credential{}
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if err := cmd.Run(); err != nil {
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t.Fatal(err)
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}
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}
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