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package validate
import (
"fmt"
"os"
"path/filepath"
"strings"
"github.com/opencontainers/runc/libcontainer/configs"
"github.com/opencontainers/runc/libcontainer/intelrdt"
selinux "github.com/opencontainers/selinux/go-selinux"
)
type Validator interface {
Validate(*configs.Config) error
}
func New() Validator {
return &ConfigValidator{}
}
type ConfigValidator struct {
}
func (v *ConfigValidator) Validate(config *configs.Config) error {
if err := v.rootfs(config); err != nil {
return err
}
if err := v.network(config); err != nil {
return err
}
if err := v.hostname(config); err != nil {
return err
}
if err := v.security(config); err != nil {
return err
}
if err := v.usernamespace(config); err != nil {
return err
}
if err := v.sysctl(config); err != nil {
return err
}
if err := v.intelrdt(config); err != nil {
return err
}
if config.Rootless {
if err := v.rootless(config); err != nil {
return err
}
}
return nil
}
// rootfs validates if the rootfs is an absolute path and is not a symlink
// to the container's root filesystem.
func (v *ConfigValidator) rootfs(config *configs.Config) error {
if _, err := os.Stat(config.Rootfs); err != nil {
if os.IsNotExist(err) {
return fmt.Errorf("rootfs (%s) does not exist", config.Rootfs)
}
return err
}
cleaned, err := filepath.Abs(config.Rootfs)
if err != nil {
return err
}
if cleaned, err = filepath.EvalSymlinks(cleaned); err != nil {
return err
}
if filepath.Clean(config.Rootfs) != cleaned {
return fmt.Errorf("%s is not an absolute path or is a symlink", config.Rootfs)
}
return nil
}
func (v *ConfigValidator) network(config *configs.Config) error {
if !config.Namespaces.Contains(configs.NEWNET) {
if len(config.Networks) > 0 || len(config.Routes) > 0 {
return fmt.Errorf("unable to apply network settings without a private NET namespace")
}
}
return nil
}
func (v *ConfigValidator) hostname(config *configs.Config) error {
if config.Hostname != "" && !config.Namespaces.Contains(configs.NEWUTS) {
return fmt.Errorf("unable to set hostname without a private UTS namespace")
}
return nil
}
func (v *ConfigValidator) security(config *configs.Config) error {
// restrict sys without mount namespace
if (len(config.MaskPaths) > 0 || len(config.ReadonlyPaths) > 0) &&
!config.Namespaces.Contains(configs.NEWNS) {
return fmt.Errorf("unable to restrict sys entries without a private MNT namespace")
}
if config.ProcessLabel != "" && !selinux.GetEnabled() {
return fmt.Errorf("selinux label is specified in config, but selinux is disabled or not supported")
}
return nil
}
func (v *ConfigValidator) usernamespace(config *configs.Config) error {
if config.Namespaces.Contains(configs.NEWUSER) {
if _, err := os.Stat("/proc/self/ns/user"); os.IsNotExist(err) {
return fmt.Errorf("USER namespaces aren't enabled in the kernel")
}
} else {
if config.UidMappings != nil || config.GidMappings != nil {
return fmt.Errorf("User namespace mappings specified, but USER namespace isn't enabled in the config")
}
}
return nil
}
// sysctl validates that the specified sysctl keys are valid or not.
// /proc/sys isn't completely namespaced and depending on which namespaces
// are specified, a subset of sysctls are permitted.
func (v *ConfigValidator) sysctl(config *configs.Config) error {
validSysctlMap := map[string]bool{
"kernel.msgmax": true,
"kernel.msgmnb": true,
"kernel.msgmni": true,
"kernel.sem": true,
"kernel.shmall": true,
"kernel.shmmax": true,
"kernel.shmmni": true,
"kernel.shm_rmid_forced": true,
}
for s := range config.Sysctl {
if validSysctlMap[s] || strings.HasPrefix(s, "fs.mqueue.") {
if config.Namespaces.Contains(configs.NEWIPC) {
continue
} else {
return fmt.Errorf("sysctl %q is not allowed in the hosts ipc namespace", s)
}
}
if strings.HasPrefix(s, "net.") {
if config.Namespaces.Contains(configs.NEWNET) {
if path := config.Namespaces.PathOf(configs.NEWNET); path != "" {
if err := checkHostNs(s, path); err != nil {
return err
}
}
continue
} else {
return fmt.Errorf("sysctl %q is not allowed in the hosts network namespace", s)
}
}
return fmt.Errorf("sysctl %q is not in a separate kernel namespace", s)
}
return nil
}
func (v *ConfigValidator) intelrdt(config *configs.Config) error {
if config.IntelRdt != nil {
if !intelrdt.IsEnabled() {
return fmt.Errorf("intelRdt is specified in config, but Intel RDT feature is not supported or enabled")
}
if config.IntelRdt.L3CacheSchema == "" {
return fmt.Errorf("intelRdt is specified in config, but intelRdt.l3CacheSchema is empty")
}
}
return nil
}
func isSymbolicLink(path string) (bool, error) {
fi, err := os.Lstat(path)
if err != nil {
return false, err
}
return fi.Mode()&os.ModeSymlink == os.ModeSymlink, nil
}
// checkHostNs checks whether network sysctl is used in host namespace.
func checkHostNs(sysctlConfig string, path string) error {
var currentProcessNetns = "/proc/self/ns/net"
// readlink on the current processes network namespace
destOfCurrentProcess, err := os.Readlink(currentProcessNetns)
if err != nil {
return fmt.Errorf("read soft link %q error", currentProcessNetns)
}
// First check if the provided path is a symbolic link
symLink, err := isSymbolicLink(path)
if err != nil {
return fmt.Errorf("could not check that %q is a symlink: %v", path, err)
}
if symLink == false {
// The provided namespace is not a symbolic link,
// it is not the host namespace.
return nil
}
// readlink on the path provided in the struct
destOfContainer, err := os.Readlink(path)
if err != nil {
return fmt.Errorf("read soft link %q error", path)
}
if destOfContainer == destOfCurrentProcess {
return fmt.Errorf("sysctl %q is not allowed in the hosts network namespace", sysctlConfig)
}
return nil
}
|
