runc/spec.go

789 lines
20 KiB
Go

// +build linux
package main
import (
"encoding/json"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"runtime"
"strconv"
"strings"
"syscall"
"github.com/Sirupsen/logrus"
"github.com/codegangsta/cli"
"github.com/opencontainers/runc/libcontainer/cgroups"
"github.com/opencontainers/runc/libcontainer/configs"
"github.com/opencontainers/runc/libcontainer/seccomp"
libcontainerUtils "github.com/opencontainers/runc/libcontainer/utils"
"github.com/opencontainers/specs"
)
var specCommand = cli.Command{
Name: "spec",
Usage: "create a new specification file",
ArgsUsage: "",
Description: `The spec command creates the new specification file named "` + specConfig + `" for the bundle." `,
Flags: []cli.Flag{
cli.StringFlag{
Name: "bundle, b",
Value: "",
Usage: "path to the root of the bundle directory",
},
},
Action: func(context *cli.Context) {
spec := specs.LinuxSpec{
Spec: specs.Spec{
Version: specs.Version,
Platform: specs.Platform{
OS: runtime.GOOS,
Arch: runtime.GOARCH,
},
Root: specs.Root{
Path: "rootfs",
Readonly: true,
},
Process: specs.Process{
Terminal: true,
User: specs.User{},
Args: []string{
"sh",
},
Env: []string{
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
"TERM=xterm",
},
Cwd: "/",
},
Hostname: "shell",
Mounts: []specs.Mount{
{
Destination: "/proc",
Type: "proc",
Source: "proc",
Options: nil,
},
{
Destination: "/dev",
Type: "tmpfs",
Source: "tmpfs",
Options: []string{"nosuid", "strictatime", "mode=755", "size=65536k"},
},
{
Destination: "/dev/pts",
Type: "devpts",
Source: "devpts",
Options: []string{"nosuid", "noexec", "newinstance", "ptmxmode=0666", "mode=0620", "gid=5"},
},
{
Destination: "/dev/shm",
Type: "tmpfs",
Source: "shm",
Options: []string{"nosuid", "noexec", "nodev", "mode=1777", "size=65536k"},
},
{
Destination: "/dev/mqueue",
Type: "mqueue",
Source: "mqueue",
Options: []string{"nosuid", "noexec", "nodev"},
},
{
Destination: "/sys",
Type: "sysfs",
Source: "sysfs",
Options: []string{"nosuid", "noexec", "nodev"},
},
{
Destination: "/sys/fs/cgroup",
Type: "cgroup",
Source: "cgroup",
Options: []string{"nosuid", "noexec", "nodev", "relatime", "ro"},
},
},
},
Linux: specs.Linux{
Capabilities: []string{
"CAP_AUDIT_WRITE",
"CAP_KILL",
"CAP_NET_BIND_SERVICE",
},
Resources: &specs.Resources{
Devices: []specs.DeviceCgroup{
{
Allow: false,
Access: sPtr("rwm"),
},
},
},
Namespaces: []specs.Namespace{
{
Type: "pid",
},
{
Type: "network",
},
{
Type: "ipc",
},
{
Type: "uts",
},
{
Type: "mount",
},
},
Rlimits: []specs.Rlimit{
{
Type: "RLIMIT_NOFILE",
Hard: uint64(1024),
Soft: uint64(1024),
},
},
NoNewPrivileges: true,
},
}
checkNoFile := func(name string) error {
_, err := os.Stat(name)
if err == nil {
return fmt.Errorf("File %s exists. Remove it first", name)
}
if !os.IsNotExist(err) {
return err
}
return nil
}
bundle := context.String("bundle")
if bundle != "" {
if err := os.Chdir(bundle); err != nil {
fatal(err)
}
}
if err := checkNoFile(specConfig); err != nil {
logrus.Fatal(err)
}
data, err := json.MarshalIndent(&spec, "", "\t")
if err != nil {
logrus.Fatal(err)
}
if err := ioutil.WriteFile(specConfig, data, 0666); err != nil {
logrus.Fatal(err)
}
},
}
func sPtr(s string) *string { return &s }
func rPtr(r rune) *rune { return &r }
func iPtr(i int64) *int64 { return &i }
func u32Ptr(i int64) *uint32 { u := uint32(i); return &u }
func fmPtr(i int64) *os.FileMode { fm := os.FileMode(i); return &fm }
var namespaceMapping = map[specs.NamespaceType]configs.NamespaceType{
specs.PIDNamespace: configs.NEWPID,
specs.NetworkNamespace: configs.NEWNET,
specs.MountNamespace: configs.NEWNS,
specs.UserNamespace: configs.NEWUSER,
specs.IPCNamespace: configs.NEWIPC,
specs.UTSNamespace: configs.NEWUTS,
}
var mountPropagationMapping = map[string]int{
"rprivate": syscall.MS_PRIVATE | syscall.MS_REC,
"private": syscall.MS_PRIVATE,
"rslave": syscall.MS_SLAVE | syscall.MS_REC,
"slave": syscall.MS_SLAVE,
"rshared": syscall.MS_SHARED | syscall.MS_REC,
"shared": syscall.MS_SHARED,
"": syscall.MS_PRIVATE | syscall.MS_REC,
}
// validateSpec validates the fields in the spec
// TODO: Add validation for other fields where applicable
func validateSpec(spec *specs.LinuxSpec) error {
if spec.Process.Cwd == "" {
return fmt.Errorf("Cwd property must not be empty")
}
if !filepath.IsAbs(spec.Process.Cwd) {
return fmt.Errorf("Cwd must be an absolute path")
}
return nil
}
// loadSpec loads the specification from the provided path.
// If the path is empty then the default path will be "config.json"
func loadSpec(cPath string) (spec *specs.LinuxSpec, err error) {
cf, err := os.Open(cPath)
if err != nil {
if os.IsNotExist(err) {
return nil, fmt.Errorf("JSON specification file %s not found", cPath)
}
return spec, err
}
defer cf.Close()
if err = json.NewDecoder(cf).Decode(&spec); err != nil {
return spec, err
}
return spec, validateSpec(spec)
}
func createLibcontainerConfig(cgroupName string, spec *specs.LinuxSpec) (*configs.Config, error) {
cwd, err := os.Getwd()
if err != nil {
return nil, err
}
rootfsPath := spec.Root.Path
if !filepath.IsAbs(rootfsPath) {
rootfsPath = filepath.Join(cwd, rootfsPath)
}
config := &configs.Config{
Rootfs: rootfsPath,
Capabilities: spec.Linux.Capabilities,
Readonlyfs: spec.Root.Readonly,
Hostname: spec.Hostname,
}
exists := false
if config.RootPropagation, exists = mountPropagationMapping[spec.Linux.RootfsPropagation]; !exists {
return nil, fmt.Errorf("rootfsPropagation=%v is not supported", spec.Linux.RootfsPropagation)
}
for _, ns := range spec.Linux.Namespaces {
t, exists := namespaceMapping[ns.Type]
if !exists {
return nil, fmt.Errorf("namespace %q does not exist", ns)
}
config.Namespaces.Add(t, ns.Path)
}
if config.Namespaces.Contains(configs.NEWNET) {
config.Networks = []*configs.Network{
{
Type: "loopback",
},
}
}
for _, m := range spec.Mounts {
config.Mounts = append(config.Mounts, createLibcontainerMount(cwd, m))
}
if err := createDevices(spec, config); err != nil {
return nil, err
}
if err := setupUserNamespace(spec, config); err != nil {
return nil, err
}
for _, rlimit := range spec.Linux.Rlimits {
rl, err := createLibContainerRlimit(rlimit)
if err != nil {
return nil, err
}
config.Rlimits = append(config.Rlimits, rl)
}
c, err := createCgroupConfig(cgroupName, spec)
if err != nil {
return nil, err
}
config.Cgroups = c
if config.Readonlyfs {
setReadonly(config)
config.MaskPaths = []string{
"/proc/kcore",
}
config.ReadonlyPaths = []string{
"/proc/sys", "/proc/sysrq-trigger", "/proc/irq", "/proc/bus",
}
}
seccomp, err := setupSeccomp(&spec.Linux.Seccomp)
if err != nil {
return nil, err
}
config.Seccomp = seccomp
config.Sysctl = spec.Linux.Sysctl
config.ProcessLabel = spec.Linux.SelinuxProcessLabel
config.AppArmorProfile = spec.Linux.ApparmorProfile
config.NoNewPrivileges = spec.Linux.NoNewPrivileges
for _, g := range spec.Process.User.AdditionalGids {
config.AdditionalGroups = append(config.AdditionalGroups, strconv.FormatUint(uint64(g), 10))
}
createHooks(spec, config)
config.Version = specs.Version
return config, nil
}
func createLibcontainerMount(cwd string, m specs.Mount) *configs.Mount {
flags, pgflags, data := parseMountOptions(m.Options)
source := m.Source
if m.Type == "bind" {
if !filepath.IsAbs(source) {
source = filepath.Join(cwd, m.Source)
}
}
return &configs.Mount{
Device: m.Type,
Source: source,
Destination: m.Destination,
Data: data,
Flags: flags,
PropagationFlags: pgflags,
}
}
func createCgroupConfig(name string, spec *specs.LinuxSpec) (*configs.Cgroup, error) {
var (
err error
myCgroupPath string
)
if spec.Linux.CgroupsPath != nil {
myCgroupPath = libcontainerUtils.CleanPath(*spec.Linux.CgroupsPath)
} else {
myCgroupPath, err = cgroups.GetThisCgroupDir("devices")
if err != nil {
return nil, err
}
myCgroupPath = filepath.Join(myCgroupPath, name)
}
c := &configs.Cgroup{
Path: myCgroupPath,
Resources: &configs.Resources{},
}
c.Resources.AllowedDevices = allowedDevices
r := spec.Linux.Resources
if r == nil {
return c, nil
}
for i, d := range spec.Linux.Resources.Devices {
var (
t = 'a'
major = int64(-1)
minor = int64(-1)
)
if d.Type != nil {
t = *d.Type
}
if d.Major != nil {
major = *d.Major
}
if d.Minor != nil {
minor = *d.Minor
}
if d.Access == nil || *d.Access == "" {
return nil, fmt.Errorf("device access at %d field canot be empty", i)
}
dd := &configs.Device{
Type: t,
Major: major,
Minor: minor,
Permissions: *d.Access,
Allow: d.Allow,
}
c.Resources.Devices = append(c.Resources.Devices, dd)
}
// append the default allowed devices to the end of the list
c.Resources.Devices = append(c.Resources.Devices, allowedDevices...)
if r.Memory != nil {
if r.Memory.Limit != nil {
c.Resources.Memory = int64(*r.Memory.Limit)
}
if r.Memory.Reservation != nil {
c.Resources.MemoryReservation = int64(*r.Memory.Reservation)
}
if r.Memory.Swap != nil {
c.Resources.MemorySwap = int64(*r.Memory.Swap)
}
if r.Memory.Kernel != nil {
c.Resources.KernelMemory = int64(*r.Memory.Kernel)
}
if r.Memory.Swappiness != nil {
c.Resources.MemorySwappiness = int64(*r.Memory.Swappiness)
}
}
if r.CPU != nil {
if r.CPU.Shares != nil {
c.Resources.CpuShares = int64(*r.CPU.Shares)
}
if r.CPU.Quota != nil {
c.Resources.CpuQuota = int64(*r.CPU.Quota)
}
if r.CPU.Period != nil {
c.Resources.CpuPeriod = int64(*r.CPU.Period)
}
if r.CPU.RealtimeRuntime != nil {
c.Resources.CpuRtRuntime = int64(*r.CPU.RealtimeRuntime)
}
if r.CPU.RealtimePeriod != nil {
c.Resources.CpuRtPeriod = int64(*r.CPU.RealtimePeriod)
}
if r.CPU.Cpus != nil {
c.Resources.CpusetCpus = *r.CPU.Cpus
}
if r.CPU.Mems != nil {
c.Resources.CpusetMems = *r.CPU.Mems
}
}
if r.Pids != nil {
c.Resources.PidsLimit = *r.Pids.Limit
}
if r.BlockIO != nil {
if r.BlockIO.Weight != nil {
c.Resources.BlkioWeight = *r.BlockIO.Weight
}
if r.BlockIO.LeafWeight != nil {
c.Resources.BlkioLeafWeight = *r.BlockIO.LeafWeight
}
if r.BlockIO.WeightDevice != nil {
for _, wd := range r.BlockIO.WeightDevice {
weightDevice := configs.NewWeightDevice(wd.Major, wd.Minor, *wd.Weight, *wd.LeafWeight)
c.Resources.BlkioWeightDevice = append(c.Resources.BlkioWeightDevice, weightDevice)
}
}
if r.BlockIO.ThrottleReadBpsDevice != nil {
for _, td := range r.BlockIO.ThrottleReadBpsDevice {
throttleDevice := configs.NewThrottleDevice(td.Major, td.Minor, *td.Rate)
c.Resources.BlkioThrottleReadBpsDevice = append(c.Resources.BlkioThrottleReadBpsDevice, throttleDevice)
}
}
if r.BlockIO.ThrottleWriteBpsDevice != nil {
for _, td := range r.BlockIO.ThrottleWriteBpsDevice {
throttleDevice := configs.NewThrottleDevice(td.Major, td.Minor, *td.Rate)
c.Resources.BlkioThrottleWriteBpsDevice = append(c.Resources.BlkioThrottleWriteBpsDevice, throttleDevice)
}
}
if r.BlockIO.ThrottleReadIOPSDevice != nil {
for _, td := range r.BlockIO.ThrottleReadIOPSDevice {
throttleDevice := configs.NewThrottleDevice(td.Major, td.Minor, *td.Rate)
c.Resources.BlkioThrottleReadIOPSDevice = append(c.Resources.BlkioThrottleReadIOPSDevice, throttleDevice)
}
}
if r.BlockIO.ThrottleWriteIOPSDevice != nil {
for _, td := range r.BlockIO.ThrottleWriteIOPSDevice {
throttleDevice := configs.NewThrottleDevice(td.Major, td.Minor, *td.Rate)
c.Resources.BlkioThrottleWriteIOPSDevice = append(c.Resources.BlkioThrottleWriteIOPSDevice, throttleDevice)
}
}
}
for _, l := range r.HugepageLimits {
c.Resources.HugetlbLimit = append(c.Resources.HugetlbLimit, &configs.HugepageLimit{
Pagesize: *l.Pagesize,
Limit: *l.Limit,
})
}
if r.DisableOOMKiller != nil {
c.Resources.OomKillDisable = *r.DisableOOMKiller
}
if r.Network != nil {
if r.Network.ClassID != nil {
c.Resources.NetClsClassid = string(*r.Network.ClassID)
}
for _, m := range r.Network.Priorities {
c.Resources.NetPrioIfpriomap = append(c.Resources.NetPrioIfpriomap, &configs.IfPrioMap{
Interface: m.Name,
Priority: int64(m.Priority),
})
}
}
return c, nil
}
func createDevices(spec *specs.LinuxSpec, config *configs.Config) error {
// add whitelisted devices
config.Devices = []*configs.Device{
{
Type: 'c',
Path: "/dev/null",
Major: 1,
Minor: 3,
FileMode: 0666,
Uid: 0,
Gid: 0,
},
{
Type: 'c',
Path: "/dev/random",
Major: 1,
Minor: 8,
FileMode: 0666,
Uid: 0,
Gid: 0,
},
{
Type: 'c',
Path: "/dev/full",
Major: 1,
Minor: 7,
FileMode: 0666,
Uid: 0,
Gid: 0,
},
{
Type: 'c',
Path: "/dev/tty",
Major: 5,
Minor: 0,
FileMode: 0666,
Uid: 0,
Gid: 0,
},
{
Type: 'c',
Path: "/dev/zero",
Major: 1,
Minor: 5,
FileMode: 0666,
Uid: 0,
Gid: 0,
},
{
Type: 'c',
Path: "/dev/urandom",
Major: 1,
Minor: 9,
FileMode: 0666,
Uid: 0,
Gid: 0,
},
}
// merge in additional devices from the spec
for _, d := range spec.Linux.Devices {
var uid, gid uint32
if d.UID != nil {
uid = *d.UID
}
if d.GID != nil {
gid = *d.GID
}
device := &configs.Device{
Type: d.Type,
Path: d.Path,
Major: d.Major,
Minor: d.Minor,
FileMode: *d.FileMode,
Uid: uid,
Gid: gid,
}
config.Devices = append(config.Devices, device)
}
return nil
}
func setReadonly(config *configs.Config) {
for _, m := range config.Mounts {
if m.Device == "sysfs" {
m.Flags |= syscall.MS_RDONLY
}
}
}
func setupUserNamespace(spec *specs.LinuxSpec, config *configs.Config) error {
if len(spec.Linux.UIDMappings) == 0 {
return nil
}
config.Namespaces.Add(configs.NEWUSER, "")
create := func(m specs.IDMapping) configs.IDMap {
return configs.IDMap{
HostID: int(m.HostID),
ContainerID: int(m.ContainerID),
Size: int(m.Size),
}
}
for _, m := range spec.Linux.UIDMappings {
config.UidMappings = append(config.UidMappings, create(m))
}
for _, m := range spec.Linux.GIDMappings {
config.GidMappings = append(config.GidMappings, create(m))
}
rootUID, err := config.HostUID()
if err != nil {
return err
}
rootGID, err := config.HostGID()
if err != nil {
return err
}
for _, node := range config.Devices {
node.Uid = uint32(rootUID)
node.Gid = uint32(rootGID)
}
return nil
}
func createLibContainerRlimit(rlimit specs.Rlimit) (configs.Rlimit, error) {
rl, err := strToRlimit(rlimit.Type)
if err != nil {
return configs.Rlimit{}, err
}
return configs.Rlimit{
Type: rl,
Hard: uint64(rlimit.Hard),
Soft: uint64(rlimit.Soft),
}, nil
}
// parseMountOptions parses the string and returns the flags, propagation
// flags and any mount data that it contains.
func parseMountOptions(options []string) (int, []int, string) {
var (
flag int
pgflag []int
data []string
)
flags := map[string]struct {
clear bool
flag int
}{
"async": {true, syscall.MS_SYNCHRONOUS},
"atime": {true, syscall.MS_NOATIME},
"bind": {false, syscall.MS_BIND},
"defaults": {false, 0},
"dev": {true, syscall.MS_NODEV},
"diratime": {true, syscall.MS_NODIRATIME},
"dirsync": {false, syscall.MS_DIRSYNC},
"exec": {true, syscall.MS_NOEXEC},
"mand": {false, syscall.MS_MANDLOCK},
"noatime": {false, syscall.MS_NOATIME},
"nodev": {false, syscall.MS_NODEV},
"nodiratime": {false, syscall.MS_NODIRATIME},
"noexec": {false, syscall.MS_NOEXEC},
"nomand": {true, syscall.MS_MANDLOCK},
"norelatime": {true, syscall.MS_RELATIME},
"nostrictatime": {true, syscall.MS_STRICTATIME},
"nosuid": {false, syscall.MS_NOSUID},
"rbind": {false, syscall.MS_BIND | syscall.MS_REC},
"relatime": {false, syscall.MS_RELATIME},
"remount": {false, syscall.MS_REMOUNT},
"ro": {false, syscall.MS_RDONLY},
"rw": {true, syscall.MS_RDONLY},
"strictatime": {false, syscall.MS_STRICTATIME},
"suid": {true, syscall.MS_NOSUID},
"sync": {false, syscall.MS_SYNCHRONOUS},
}
propagationFlags := map[string]struct {
clear bool
flag int
}{
"private": {false, syscall.MS_PRIVATE},
"shared": {false, syscall.MS_SHARED},
"slave": {false, syscall.MS_SLAVE},
"unbindable": {false, syscall.MS_UNBINDABLE},
"rprivate": {false, syscall.MS_PRIVATE | syscall.MS_REC},
"rshared": {false, syscall.MS_SHARED | syscall.MS_REC},
"rslave": {false, syscall.MS_SLAVE | syscall.MS_REC},
"runbindable": {false, syscall.MS_UNBINDABLE | syscall.MS_REC},
}
for _, o := range options {
// If the option does not exist in the flags table or the flag
// is not supported on the platform,
// then it is a data value for a specific fs type
if f, exists := flags[o]; exists && f.flag != 0 {
if f.clear {
flag &= ^f.flag
} else {
flag |= f.flag
}
} else if f, exists := propagationFlags[o]; exists && f.flag != 0 {
pgflag = append(pgflag, f.flag)
} else {
data = append(data, o)
}
}
return flag, pgflag, strings.Join(data, ",")
}
func setupSeccomp(config *specs.Seccomp) (*configs.Seccomp, error) {
if config == nil {
return nil, nil
}
// No default action specified, no syscalls listed, assume seccomp disabled
if config.DefaultAction == "" && len(config.Syscalls) == 0 {
return nil, nil
}
newConfig := new(configs.Seccomp)
newConfig.Syscalls = []*configs.Syscall{}
if len(config.Architectures) > 0 {
newConfig.Architectures = []string{}
for _, arch := range config.Architectures {
newArch, err := seccomp.ConvertStringToArch(string(arch))
if err != nil {
return nil, err
}
newConfig.Architectures = append(newConfig.Architectures, newArch)
}
}
// Convert default action from string representation
newDefaultAction, err := seccomp.ConvertStringToAction(string(config.DefaultAction))
if err != nil {
return nil, err
}
newConfig.DefaultAction = newDefaultAction
// Loop through all syscall blocks and convert them to libcontainer format
for _, call := range config.Syscalls {
newAction, err := seccomp.ConvertStringToAction(string(call.Action))
if err != nil {
return nil, err
}
newCall := configs.Syscall{
Name: call.Name,
Action: newAction,
Args: []*configs.Arg{},
}
// Loop through all the arguments of the syscall and convert them
for _, arg := range call.Args {
newOp, err := seccomp.ConvertStringToOperator(string(arg.Op))
if err != nil {
return nil, err
}
newArg := configs.Arg{
Index: arg.Index,
Value: arg.Value,
ValueTwo: arg.ValueTwo,
Op: newOp,
}
newCall.Args = append(newCall.Args, &newArg)
}
newConfig.Syscalls = append(newConfig.Syscalls, &newCall)
}
return newConfig, nil
}
func createHooks(rspec *specs.LinuxSpec, config *configs.Config) {
config.Hooks = &configs.Hooks{}
for _, h := range rspec.Hooks.Prestart {
cmd := configs.Command{
Path: h.Path,
Args: h.Args,
Env: h.Env,
}
config.Hooks.Prestart = append(config.Hooks.Prestart, configs.NewCommandHook(cmd))
}
for _, h := range rspec.Hooks.Poststart {
cmd := configs.Command{
Path: h.Path,
Args: h.Args,
Env: h.Env,
}
config.Hooks.Poststart = append(config.Hooks.Poststart, configs.NewCommandHook(cmd))
}
for _, h := range rspec.Hooks.Poststop {
cmd := configs.Command{
Path: h.Path,
Args: h.Args,
Env: h.Env,
}
config.Hooks.Poststop = append(config.Hooks.Poststop, configs.NewCommandHook(cmd))
}
}