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moby--moby/daemon/create.go
Brian Goff e908cc3901 Use real root with 0701 perms
Various dirs in /var/lib/docker contain data that needs to be mounted
into a container. For this reason, these dirs are set to be owned by the
remapped root user, otherwise there can be permissions issues.
However, this uneccessarily exposes these dirs to an unprivileged user
on the host.

Instead, set the ownership of these dirs to the real root (or rather the
UID/GID of dockerd) with 0701 permissions, which allows the remapped
root to enter the directories but not read/write to them.
The remapped root needs to enter these dirs so the container's rootfs
can be configured... e.g. to mount /etc/resolve.conf.

This prevents an unprivileged user from having read/write access to
these dirs on the host.
The flip side of this is now any user can enter these directories.

Signed-off-by: Brian Goff <cpuguy83@gmail.com>
2021-01-26 17:23:32 +00:00

360 lines
12 KiB
Go

package daemon // import "github.com/docker/docker/daemon"
import (
"fmt"
"net"
"runtime"
"strings"
"time"
"github.com/containerd/containerd/platforms"
"github.com/docker/docker/api/types"
containertypes "github.com/docker/docker/api/types/container"
networktypes "github.com/docker/docker/api/types/network"
"github.com/docker/docker/container"
"github.com/docker/docker/errdefs"
"github.com/docker/docker/image"
"github.com/docker/docker/pkg/idtools"
"github.com/docker/docker/pkg/system"
"github.com/docker/docker/runconfig"
v1 "github.com/opencontainers/image-spec/specs-go/v1"
"github.com/opencontainers/selinux/go-selinux"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
)
type createOpts struct {
params types.ContainerCreateConfig
managed bool
ignoreImagesArgsEscaped bool
}
// CreateManagedContainer creates a container that is managed by a Service
func (daemon *Daemon) CreateManagedContainer(params types.ContainerCreateConfig) (containertypes.ContainerCreateCreatedBody, error) {
return daemon.containerCreate(createOpts{
params: params,
managed: true,
ignoreImagesArgsEscaped: false})
}
// ContainerCreate creates a regular container
func (daemon *Daemon) ContainerCreate(params types.ContainerCreateConfig) (containertypes.ContainerCreateCreatedBody, error) {
return daemon.containerCreate(createOpts{
params: params,
managed: false,
ignoreImagesArgsEscaped: false})
}
// ContainerCreateIgnoreImagesArgsEscaped creates a regular container. This is called from the builder RUN case
// and ensures that we do not take the images ArgsEscaped
func (daemon *Daemon) ContainerCreateIgnoreImagesArgsEscaped(params types.ContainerCreateConfig) (containertypes.ContainerCreateCreatedBody, error) {
return daemon.containerCreate(createOpts{
params: params,
managed: false,
ignoreImagesArgsEscaped: true})
}
func (daemon *Daemon) containerCreate(opts createOpts) (containertypes.ContainerCreateCreatedBody, error) {
start := time.Now()
if opts.params.Config == nil {
return containertypes.ContainerCreateCreatedBody{}, errdefs.InvalidParameter(errors.New("Config cannot be empty in order to create a container"))
}
os := runtime.GOOS
var img *image.Image
if opts.params.Config.Image != "" {
var err error
img, err = daemon.imageService.GetImage(opts.params.Config.Image, opts.params.Platform)
if err == nil {
os = img.OS
}
} else {
// This mean scratch. On Windows, we can safely assume that this is a linux
// container. On other platforms, it's the host OS (which it already is)
if isWindows && system.LCOWSupported() {
os = "linux"
}
}
warnings, err := daemon.verifyContainerSettings(os, opts.params.HostConfig, opts.params.Config, false)
if err != nil {
return containertypes.ContainerCreateCreatedBody{Warnings: warnings}, errdefs.InvalidParameter(err)
}
if img != nil && opts.params.Platform == nil {
p := platforms.DefaultSpec()
imgPlat := v1.Platform{
OS: img.OS,
Architecture: img.Architecture,
Variant: img.Variant,
}
if !platforms.Only(p).Match(imgPlat) {
warnings = append(warnings, fmt.Sprintf("The requested image's platform (%s) does not match the detected host platform (%s) and no specific platform was requested", platforms.Format(imgPlat), platforms.Format(p)))
}
}
err = verifyNetworkingConfig(opts.params.NetworkingConfig)
if err != nil {
return containertypes.ContainerCreateCreatedBody{Warnings: warnings}, errdefs.InvalidParameter(err)
}
if opts.params.HostConfig == nil {
opts.params.HostConfig = &containertypes.HostConfig{}
}
err = daemon.adaptContainerSettings(opts.params.HostConfig, opts.params.AdjustCPUShares)
if err != nil {
return containertypes.ContainerCreateCreatedBody{Warnings: warnings}, errdefs.InvalidParameter(err)
}
ctr, err := daemon.create(opts)
if err != nil {
return containertypes.ContainerCreateCreatedBody{Warnings: warnings}, err
}
containerActions.WithValues("create").UpdateSince(start)
if warnings == nil {
warnings = make([]string, 0) // Create an empty slice to avoid https://github.com/moby/moby/issues/38222
}
return containertypes.ContainerCreateCreatedBody{ID: ctr.ID, Warnings: warnings}, nil
}
// Create creates a new container from the given configuration with a given name.
func (daemon *Daemon) create(opts createOpts) (retC *container.Container, retErr error) {
var (
ctr *container.Container
img *image.Image
imgID image.ID
err error
)
os := runtime.GOOS
if opts.params.Config.Image != "" {
img, err = daemon.imageService.GetImage(opts.params.Config.Image, opts.params.Platform)
if err != nil {
return nil, err
}
if img.OS != "" {
os = img.OS
} else {
// default to the host OS except on Windows with LCOW
if isWindows && system.LCOWSupported() {
os = "linux"
}
}
imgID = img.ID()
if isWindows && img.OS == "linux" && !system.LCOWSupported() {
return nil, errors.New("operating system on which parent image was created is not Windows")
}
} else {
if isWindows {
os = "linux" // 'scratch' case.
}
}
// On WCOW, if are not being invoked by the builder to create this container (where
// ignoreImagesArgEscaped will be true) - if the image already has its arguments escaped,
// ensure that this is replicated across to the created container to avoid double-escaping
// of the arguments/command line when the runtime attempts to run the container.
if os == "windows" && !opts.ignoreImagesArgsEscaped && img != nil && img.RunConfig().ArgsEscaped {
opts.params.Config.ArgsEscaped = true
}
if err := daemon.mergeAndVerifyConfig(opts.params.Config, img); err != nil {
return nil, errdefs.InvalidParameter(err)
}
if err := daemon.mergeAndVerifyLogConfig(&opts.params.HostConfig.LogConfig); err != nil {
return nil, errdefs.InvalidParameter(err)
}
if ctr, err = daemon.newContainer(opts.params.Name, os, opts.params.Config, opts.params.HostConfig, imgID, opts.managed); err != nil {
return nil, err
}
defer func() {
if retErr != nil {
if err := daemon.cleanupContainer(ctr, true, true); err != nil {
logrus.Errorf("failed to cleanup container on create error: %v", err)
}
}
}()
if err := daemon.setSecurityOptions(ctr, opts.params.HostConfig); err != nil {
return nil, err
}
ctr.HostConfig.StorageOpt = opts.params.HostConfig.StorageOpt
// Fixes: https://github.com/moby/moby/issues/34074 and
// https://github.com/docker/for-win/issues/999.
// Merge the daemon's storage options if they aren't already present. We only
// do this on Windows as there's no effective sandbox size limit other than
// physical on Linux.
if isWindows {
if ctr.HostConfig.StorageOpt == nil {
ctr.HostConfig.StorageOpt = make(map[string]string)
}
for _, v := range daemon.configStore.GraphOptions {
opt := strings.SplitN(v, "=", 2)
if _, ok := ctr.HostConfig.StorageOpt[opt[0]]; !ok {
ctr.HostConfig.StorageOpt[opt[0]] = opt[1]
}
}
}
// Set RWLayer for container after mount labels have been set
rwLayer, err := daemon.imageService.CreateLayer(ctr, setupInitLayer(daemon.idMapping))
if err != nil {
return nil, errdefs.System(err)
}
ctr.RWLayer = rwLayer
if err := idtools.MkdirAndChown(ctr.Root, 0701, idtools.CurrentIdentity()); err != nil {
return nil, err
}
if err := idtools.MkdirAndChown(ctr.CheckpointDir(), 0700, idtools.CurrentIdentity()); err != nil {
return nil, err
}
if err := daemon.setHostConfig(ctr, opts.params.HostConfig); err != nil {
return nil, err
}
if err := daemon.createContainerOSSpecificSettings(ctr, opts.params.Config, opts.params.HostConfig); err != nil {
return nil, err
}
var endpointsConfigs map[string]*networktypes.EndpointSettings
if opts.params.NetworkingConfig != nil {
endpointsConfigs = opts.params.NetworkingConfig.EndpointsConfig
}
// Make sure NetworkMode has an acceptable value. We do this to ensure
// backwards API compatibility.
runconfig.SetDefaultNetModeIfBlank(ctr.HostConfig)
daemon.updateContainerNetworkSettings(ctr, endpointsConfigs)
if err := daemon.Register(ctr); err != nil {
return nil, err
}
stateCtr.set(ctr.ID, "stopped")
daemon.LogContainerEvent(ctr, "create")
return ctr, nil
}
func toHostConfigSelinuxLabels(labels []string) []string {
for i, l := range labels {
labels[i] = "label=" + l
}
return labels
}
func (daemon *Daemon) generateSecurityOpt(hostConfig *containertypes.HostConfig) ([]string, error) {
for _, opt := range hostConfig.SecurityOpt {
con := strings.Split(opt, "=")
if con[0] == "label" {
// Caller overrode SecurityOpts
return nil, nil
}
}
ipcMode := hostConfig.IpcMode
pidMode := hostConfig.PidMode
privileged := hostConfig.Privileged
if ipcMode.IsHost() || pidMode.IsHost() || privileged {
return toHostConfigSelinuxLabels(selinux.DisableSecOpt()), nil
}
var ipcLabel []string
var pidLabel []string
ipcContainer := ipcMode.Container()
pidContainer := pidMode.Container()
if ipcContainer != "" {
c, err := daemon.GetContainer(ipcContainer)
if err != nil {
return nil, err
}
ipcLabel, err = selinux.DupSecOpt(c.ProcessLabel)
if err != nil {
return nil, err
}
if pidContainer == "" {
return toHostConfigSelinuxLabels(ipcLabel), err
}
}
if pidContainer != "" {
c, err := daemon.GetContainer(pidContainer)
if err != nil {
return nil, err
}
pidLabel, err = selinux.DupSecOpt(c.ProcessLabel)
if err != nil {
return nil, err
}
if ipcContainer == "" {
return toHostConfigSelinuxLabels(pidLabel), err
}
}
if pidLabel != nil && ipcLabel != nil {
for i := 0; i < len(pidLabel); i++ {
if pidLabel[i] != ipcLabel[i] {
return nil, fmt.Errorf("--ipc and --pid containers SELinux labels aren't the same")
}
}
return toHostConfigSelinuxLabels(pidLabel), nil
}
return nil, nil
}
func (daemon *Daemon) mergeAndVerifyConfig(config *containertypes.Config, img *image.Image) error {
if img != nil && img.Config != nil {
if err := merge(config, img.Config); err != nil {
return err
}
}
// Reset the Entrypoint if it is [""]
if len(config.Entrypoint) == 1 && config.Entrypoint[0] == "" {
config.Entrypoint = nil
}
if len(config.Entrypoint) == 0 && len(config.Cmd) == 0 {
return fmt.Errorf("No command specified")
}
return nil
}
// Checks if the client set configurations for more than one network while creating a container
// Also checks if the IPAMConfig is valid
func verifyNetworkingConfig(nwConfig *networktypes.NetworkingConfig) error {
if nwConfig == nil || len(nwConfig.EndpointsConfig) == 0 {
return nil
}
if len(nwConfig.EndpointsConfig) > 1 {
l := make([]string, 0, len(nwConfig.EndpointsConfig))
for k := range nwConfig.EndpointsConfig {
l = append(l, k)
}
return errors.Errorf("Container cannot be connected to network endpoints: %s", strings.Join(l, ", "))
}
for k, v := range nwConfig.EndpointsConfig {
if v == nil {
return errdefs.InvalidParameter(errors.Errorf("no EndpointSettings for %s", k))
}
if v.IPAMConfig != nil {
if v.IPAMConfig.IPv4Address != "" && net.ParseIP(v.IPAMConfig.IPv4Address).To4() == nil {
return errors.Errorf("invalid IPv4 address: %s", v.IPAMConfig.IPv4Address)
}
if v.IPAMConfig.IPv6Address != "" {
n := net.ParseIP(v.IPAMConfig.IPv6Address)
// if the address is an invalid network address (ParseIP == nil) or if it is
// an IPv4 address (To4() != nil), then it is an invalid IPv6 address
if n == nil || n.To4() != nil {
return errors.Errorf("invalid IPv6 address: %s", v.IPAMConfig.IPv6Address)
}
}
}
}
return nil
}