/
validator.go
133 lines (119 loc) · 3.56 KB
/
validator.go
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package validate
import (
"fmt"
"os"
"path/filepath"
"strings"
"github.com/opencontainers/runc/libcontainer/configs"
)
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
}
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 {
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")
}
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) {
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
}