github.com/jonasi/go@v0.0.0-20150930005915-e78e654c1de0/src/syscall/exec_linux_test.go (about)

     1  // Copyright 2015 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // +build linux
     6  
     7  package syscall_test
     8  
     9  import (
    10  	"io/ioutil"
    11  	"os"
    12  	"os/exec"
    13  	"strings"
    14  	"syscall"
    15  	"testing"
    16  )
    17  
    18  func whoamiCmd(t *testing.T, uid, gid int, setgroups bool) *exec.Cmd {
    19  	if _, err := os.Stat("/proc/self/ns/user"); err != nil {
    20  		if os.IsNotExist(err) {
    21  			t.Skip("kernel doesn't support user namespaces")
    22  		}
    23  		t.Fatalf("Failed to stat /proc/self/ns/user: %v", err)
    24  	}
    25  	// On some systems, there is a sysctl setting.
    26  	if os.Getuid() != 0 {
    27  		data, errRead := ioutil.ReadFile("/proc/sys/kernel/unprivileged_userns_clone")
    28  		if errRead == nil && data[0] == '0' {
    29  			t.Skip("kernel prohibits user namespace in unprivileged process")
    30  		}
    31  	}
    32  	cmd := exec.Command("whoami")
    33  	cmd.SysProcAttr = &syscall.SysProcAttr{
    34  		Cloneflags: syscall.CLONE_NEWUSER,
    35  		UidMappings: []syscall.SysProcIDMap{
    36  			{ContainerID: 0, HostID: uid, Size: 1},
    37  		},
    38  		GidMappings: []syscall.SysProcIDMap{
    39  			{ContainerID: 0, HostID: gid, Size: 1},
    40  		},
    41  		GidMappingsEnableSetgroups: setgroups,
    42  	}
    43  	return cmd
    44  }
    45  
    46  func testNEWUSERRemap(t *testing.T, uid, gid int, setgroups bool) {
    47  	cmd := whoamiCmd(t, uid, gid, setgroups)
    48  	out, err := cmd.CombinedOutput()
    49  	if err != nil {
    50  		t.Fatalf("Cmd failed with err %v, output: %s", err, out)
    51  	}
    52  	sout := strings.TrimSpace(string(out))
    53  	want := "root"
    54  	if sout != want {
    55  		t.Fatalf("whoami = %q; want %q", out, want)
    56  	}
    57  }
    58  
    59  func TestCloneNEWUSERAndRemapRootDisableSetgroups(t *testing.T) {
    60  	if os.Getuid() != 0 {
    61  		t.Skip("skipping root only test")
    62  	}
    63  	testNEWUSERRemap(t, 0, 0, false)
    64  }
    65  
    66  func TestCloneNEWUSERAndRemapRootEnableSetgroups(t *testing.T) {
    67  	if os.Getuid() != 0 {
    68  		t.Skip("skipping root only test")
    69  	}
    70  	testNEWUSERRemap(t, 0, 0, false)
    71  }
    72  
    73  func TestCloneNEWUSERAndRemapNoRootDisableSetgroups(t *testing.T) {
    74  	if os.Getuid() == 0 {
    75  		t.Skip("skipping unprivileged user only test")
    76  	}
    77  	testNEWUSERRemap(t, os.Getuid(), os.Getgid(), false)
    78  }
    79  
    80  func TestCloneNEWUSERAndRemapNoRootSetgroupsEnableSetgroups(t *testing.T) {
    81  	if os.Getuid() == 0 {
    82  		t.Skip("skipping unprivileged user only test")
    83  	}
    84  	cmd := whoamiCmd(t, os.Getuid(), os.Getgid(), true)
    85  	err := cmd.Run()
    86  	if err == nil {
    87  		t.Skip("probably old kernel without security fix")
    88  	}
    89  	if !os.IsPermission(err) {
    90  		t.Fatalf("Unprivileged gid_map rewriting with GidMappingsEnableSetgroups must fail")
    91  	}
    92  }
    93  
    94  func TestEmptyCredGroupsDisableSetgroups(t *testing.T) {
    95  	cmd := whoamiCmd(t, os.Getuid(), os.Getgid(), false)
    96  	cmd.SysProcAttr.Credential = &syscall.Credential{}
    97  	if err := cmd.Run(); err != nil {
    98  		t.Fatal(err)
    99  	}
   100  }