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remoteenforcer_linux.go
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remoteenforcer_linux.go
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// +build linux
package remoteenforcer
/*
#cgo CFLAGS: -Wall
#include <stdlib.h>
*/
import "C"
import (
"context"
"fmt"
"os"
"os/exec"
"os/signal"
"strconv"
"strings"
"sync"
"syscall"
_ "go.aporeto.io/trireme-lib/controller/internal/enforcer/utils/nsenter" // nolint
"go.aporeto.io/trireme-lib/controller/constants"
"go.aporeto.io/trireme-lib/controller/internal/enforcer"
"go.aporeto.io/trireme-lib/controller/internal/enforcer/utils/rpcwrapper"
"go.aporeto.io/trireme-lib/controller/internal/supervisor"
"go.aporeto.io/trireme-lib/controller/pkg/packetprocessor"
"go.aporeto.io/trireme-lib/controller/pkg/remoteenforcer/internal/statsclient"
"go.aporeto.io/trireme-lib/controller/pkg/remoteenforcer/internal/statscollector"
"go.aporeto.io/trireme-lib/controller/pkg/secrets"
"go.aporeto.io/trireme-lib/policy"
"go.uber.org/zap"
"golang.org/x/sys/unix"
)
var cmdLock sync.Mutex
// newServer starts a new server
func newServer(
ctx context.Context,
cancel context.CancelFunc,
service packetprocessor.PacketProcessor,
rpcHandle rpcwrapper.RPCServer,
rpcChannel string,
secret string,
statsClient statsclient.StatsClient,
) (s RemoteIntf, err error) {
var collector statscollector.Collector
if statsClient == nil {
collector = statscollector.NewCollector()
statsClient, err = statsclient.NewStatsClient(collector)
if err != nil {
return nil, err
}
}
procMountPoint := os.Getenv(constants.EnvMountPoint)
if procMountPoint == "" {
procMountPoint = constants.DefaultProcMountPoint
}
return &RemoteEnforcer{
collector: collector,
service: service,
rpcChannel: rpcChannel,
rpcSecret: secret,
rpcHandle: rpcHandle,
procMountPoint: procMountPoint,
statsClient: statsClient,
ctx: ctx,
cancel: cancel,
}, nil
}
// getCEnvVariable returns an environment variable set in the c context
func getCEnvVariable(name string) string {
val := C.getenv(C.CString(name))
if val == nil {
return ""
}
return C.GoString(val)
}
// setup an enforcer
func (s *RemoteEnforcer) setupEnforcer(req rpcwrapper.Request) error {
var err error
if s.enforcer != nil {
return nil
}
payload := req.Payload.(rpcwrapper.InitRequestPayload)
s.secrets, err = secrets.NewSecrets(payload.Secrets)
if err != nil {
return err
}
if s.enforcer, err = enforcer.New(
payload.MutualAuth,
payload.FqConfig,
s.collector,
s.service,
s.secrets,
payload.ServerID,
payload.Validity,
constants.RemoteContainer,
s.procMountPoint,
payload.ExternalIPCacheTimeout,
payload.PacketLogs,
payload.TargetNetworks,
); err != nil || s.enforcer == nil {
return fmt.Errorf("Error while initializing remote enforcer, %s", err)
}
return nil
}
// InitEnforcer is a function called from the controller using RPC. It intializes
// data structure required by the remote enforcer
func (s *RemoteEnforcer) InitEnforcer(req rpcwrapper.Request, resp *rpcwrapper.Response) error {
// Check if successfully switched namespace
nsEnterState := getCEnvVariable(constants.EnvNsenterErrorState)
nsEnterLogMsg := getCEnvVariable(constants.EnvNsenterLogs)
if nsEnterState != "" {
zap.L().Error("Remote enforcer failed",
zap.String("nsErr", nsEnterState),
zap.String("nsLogs", nsEnterLogMsg),
)
resp.Status = fmt.Sprintf("Remote enforcer failed: %s", nsEnterState)
return fmt.Errorf(resp.Status)
}
pid := strconv.Itoa(os.Getpid())
netns, err := exec.Command("ip", "netns", "identify", pid).Output()
if err != nil {
zap.L().Error("Remote enforcer failed: unable to identify namespace",
zap.String("nsErr", nsEnterState),
zap.String("nsLogs", nsEnterLogMsg),
zap.Error(err),
)
resp.Status = fmt.Sprintf("Remote enforcer failed: unable to identify namespace: %s", err)
// TODO: resp.Status get overwritten at the end of this func. This is the only place where we don't return the status as error
// Could we get rid of status and just always return an error ?
//
// Dont return error to close RPC channel
}
netnsString := strings.TrimSpace(string(netns))
if netnsString == "" {
zap.L().Error("Remote enforcer failed: not running in a namespace",
zap.String("nsErr", nsEnterState),
zap.String("nsLogs", nsEnterLogMsg),
)
resp.Status = "not running in a namespace"
// TODO: resp.Status get overwritten at the end of this func. This is the only place where we don't return the status as error
// Could we get rid of status and just always return an error ?
//
// Dont return error to close RPC channel
}
zap.L().Debug("Remote enforcer launched",
zap.String("nsLogs", nsEnterLogMsg),
)
if !s.rpcHandle.CheckValidity(&req, s.rpcSecret) {
resp.Status = fmt.Sprintf("init message authentication failed: %s", resp.Status)
return fmt.Errorf(resp.Status)
}
cmdLock.Lock()
defer cmdLock.Unlock()
if err := s.setupEnforcer(req); err != nil {
resp.Status = err.Error()
return fmt.Errorf(resp.Status)
}
if err := s.enforcer.Run(s.ctx); err != nil {
resp.Status = err.Error()
return fmt.Errorf(resp.Status)
}
if err := s.statsClient.Run(s.ctx); err != nil {
resp.Status = err.Error()
return fmt.Errorf(resp.Status)
}
resp.Status = ""
return nil
}
// InitSupervisor is a function called from the controller over RPC. It initializes data structure required by the supervisor
func (s *RemoteEnforcer) InitSupervisor(req rpcwrapper.Request, resp *rpcwrapper.Response) error {
if !s.rpcHandle.CheckValidity(&req, s.rpcSecret) {
resp.Status = fmt.Sprintf("supervisor init message auth failed")
return fmt.Errorf(resp.Status)
}
cmdLock.Lock()
defer cmdLock.Unlock()
payload := req.Payload.(rpcwrapper.InitSupervisorPayload)
if s.supervisor == nil {
if payload.CaptureMethod != rpcwrapper.IPTables {
return fmt.Errorf("Unsupported method")
}
supervisorHandle, err := supervisor.NewSupervisor(
s.collector,
s.enforcer,
constants.RemoteContainer,
payload.TriremeNetworks,
s.service,
)
if err != nil {
zap.L().Error("unable to instantiate the iptables supervisor", zap.Error(err))
return err
}
s.supervisor = supervisorHandle
if err := s.supervisor.Run(s.ctx); err != nil {
zap.L().Error("unable to start the supervisor", zap.Error(err))
}
} else {
if err := s.supervisor.SetTargetNetworks(payload.TriremeNetworks); err != nil {
zap.L().Error("unable to set target networks", zap.Error(err))
}
}
resp.Status = ""
return nil
}
// Supervise This method calls the supervisor method on the supervisor created during initsupervisor
func (s *RemoteEnforcer) Supervise(req rpcwrapper.Request, resp *rpcwrapper.Response) error {
if !s.rpcHandle.CheckValidity(&req, s.rpcSecret) {
resp.Status = fmt.Sprintf("supervise message auth failed")
return fmt.Errorf(resp.Status)
}
cmdLock.Lock()
defer cmdLock.Unlock()
payload := req.Payload.(rpcwrapper.SuperviseRequestPayload)
puInfo := &policy.PUInfo{
ContextID: payload.ContextID,
Policy: payload.Policy.ToPrivatePolicy(false),
Runtime: policy.NewPURuntimeWithDefaults(),
}
// TODO - Set PID to 1 - needed only for statistics
puInfo.Runtime.SetPid(1)
err := s.supervisor.Supervise(payload.ContextID, puInfo)
if err != nil {
zap.L().Error("unable to initialize supervisor",
zap.String("ContextID", payload.ContextID),
zap.Error(err),
)
resp.Status = err.Error()
return err
}
return nil
}
// Unenforce this method calls the unenforce method on the enforcer created from initenforcer
func (s *RemoteEnforcer) Unenforce(req rpcwrapper.Request, resp *rpcwrapper.Response) error {
if !s.rpcHandle.CheckValidity(&req, s.rpcSecret) {
resp.Status = "unenforce message auth failed"
return fmt.Errorf(resp.Status)
}
cmdLock.Lock()
defer cmdLock.Unlock()
payload := req.Payload.(rpcwrapper.UnEnforcePayload)
return s.enforcer.Unenforce(payload.ContextID)
}
// Unsupervise This method calls the unsupervise method on the supervisor created during initsupervisor
func (s *RemoteEnforcer) Unsupervise(req rpcwrapper.Request, resp *rpcwrapper.Response) error {
if !s.rpcHandle.CheckValidity(&req, s.rpcSecret) {
resp.Status = "unsupervise message auth failed"
return fmt.Errorf(resp.Status)
}
cmdLock.Lock()
defer cmdLock.Unlock()
payload := req.Payload.(rpcwrapper.UnSupervisePayload)
return s.supervisor.Unsupervise(payload.ContextID)
}
// SetTargetNetworks calls the same method on the actual enforcer
func (s *RemoteEnforcer) SetTargetNetworks(req rpcwrapper.Request, resp *rpcwrapper.Response) error {
var err error
if !s.rpcHandle.CheckValidity(&req, s.rpcSecret) {
resp.Status = "SetTargetNetworks message auth failed" //nolint
return fmt.Errorf(resp.Status)
}
cmdLock.Lock()
defer cmdLock.Unlock()
if s.enforcer == nil {
return fmt.Errorf(resp.Status)
}
payload := req.Payload.(rpcwrapper.SetTargetNetworks)
err = s.enforcer.SetTargetNetworks(payload.TargetNetworks)
if err != nil {
return err
}
return nil
}
// Enforce this method calls the enforce method on the enforcer created during initenforcer
func (s *RemoteEnforcer) Enforce(req rpcwrapper.Request, resp *rpcwrapper.Response) error {
if !s.rpcHandle.CheckValidity(&req, s.rpcSecret) {
resp.Status = "enforce message auth failed"
return fmt.Errorf(resp.Status)
}
cmdLock.Lock()
defer cmdLock.Unlock()
payload := req.Payload.(rpcwrapper.EnforcePayload)
puInfo := &policy.PUInfo{
ContextID: payload.ContextID,
Policy: payload.Policy.ToPrivatePolicy(true),
Runtime: policy.NewPURuntimeWithDefaults(),
}
if s.enforcer == nil {
resp.Status = "enforcer not initialized - cannot enforce"
zap.L().Error(resp.Status)
return fmt.Errorf(resp.Status)
}
if err := s.enforcer.Enforce(payload.ContextID, puInfo); err != nil {
resp.Status = err.Error()
return err
}
resp.Status = ""
return nil
}
// EnforcerExit is processing messages from the remote that are requesting an exit. In this
// case we simply cancel the context.
func (s *RemoteEnforcer) EnforcerExit(req rpcwrapper.Request, resp *rpcwrapper.Response) error {
if s.supervisor != nil {
s.supervisor.CleanUp() // nolint
}
s.cancel()
return nil
}
// UpdateSecrets updates the secrets used by the remote enforcer
func (s *RemoteEnforcer) UpdateSecrets(req rpcwrapper.Request, resp *rpcwrapper.Response) error {
var err error
if !s.rpcHandle.CheckValidity(&req, s.rpcSecret) {
resp.Status = "enforce message auth failed"
return fmt.Errorf(resp.Status)
}
cmdLock.Lock()
defer cmdLock.Unlock()
if s.enforcer == nil {
return fmt.Errorf(resp.Status)
}
payload := req.Payload.(rpcwrapper.UpdateSecretsPayload)
s.secrets, err = secrets.NewSecrets(payload.Secrets)
if err != nil {
return err
}
err = s.enforcer.UpdateSecrets(s.secrets)
if err != nil {
return err
}
return nil
}
// LaunchRemoteEnforcer launches a remote enforcer
func LaunchRemoteEnforcer(service packetprocessor.PacketProcessor) error {
ctx, cancelMainCtx := context.WithCancel(context.Background())
defer cancelMainCtx()
namedPipe := os.Getenv(constants.EnvContextSocket)
secret := os.Getenv(constants.EnvRPCClientSecret)
if secret == "" {
zap.L().Fatal("No secret found")
}
flag := unix.SIGHUP
if err := unix.Prctl(unix.PR_SET_PDEATHSIG, uintptr(flag), 0, 0, 0); err != nil {
return err
}
rpcHandle := rpcwrapper.NewRPCServer()
server, err := newServer(ctx, cancelMainCtx, service, rpcHandle, namedPipe, secret, nil)
if err != nil {
return err
}
go func() {
if err := rpcHandle.StartServer(ctx, "unix", namedPipe, server); err != nil {
zap.L().Fatal("Failed to start the server", zap.Error(err))
}
}()
c := make(chan os.Signal, 1)
signal.Notify(c, syscall.SIGTERM, syscall.SIGINT, syscall.SIGQUIT)
<-c
if err := server.EnforcerExit(rpcwrapper.Request{}, &rpcwrapper.Response{}); err != nil {
zap.L().Fatal("Failed to stop the server", zap.Error(err))
}
return nil
}