open-vault/command/agentproxyshared/auth/auth.go

554 lines
15 KiB
Go

// Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: MPL-2.0
package auth
import (
"context"
"encoding/json"
"errors"
"math/rand"
"net/http"
"time"
"github.com/armon/go-metrics"
"github.com/hashicorp/go-hclog"
"github.com/hashicorp/vault/api"
"github.com/hashicorp/vault/sdk/helper/jsonutil"
)
const (
defaultMinBackoff = 1 * time.Second
defaultMaxBackoff = 5 * time.Minute
)
// AuthMethod is the interface that auto-auth methods implement for the agent/proxy
// to use.
type AuthMethod interface {
// Authenticate returns a mount path, header, request body, and error.
// The header may be nil if no special header is needed.
Authenticate(context.Context, *api.Client) (string, http.Header, map[string]interface{}, error)
NewCreds() chan struct{}
CredSuccess()
Shutdown()
}
// AuthMethodWithClient is an extended interface that can return an API client
// for use during the authentication call.
type AuthMethodWithClient interface {
AuthMethod
AuthClient(client *api.Client) (*api.Client, error)
}
type AuthConfig struct {
Logger hclog.Logger
MountPath string
WrapTTL time.Duration
Config map[string]interface{}
}
// AuthHandler is responsible for keeping a token alive and renewed and passing
// new tokens to the sink server
type AuthHandler struct {
OutputCh chan string
TemplateTokenCh chan string
ExecTokenCh chan string
token string
userAgent string
metricsSignifier string
logger hclog.Logger
client *api.Client
random *rand.Rand
wrapTTL time.Duration
maxBackoff time.Duration
minBackoff time.Duration
enableReauthOnNewCredentials bool
enableTemplateTokenCh bool
enableExecTokenCh bool
exitOnError bool
}
type AuthHandlerConfig struct {
Logger hclog.Logger
Client *api.Client
WrapTTL time.Duration
MaxBackoff time.Duration
MinBackoff time.Duration
Token string
// UserAgent is the HTTP UserAgent header auto-auth will use when
// communicating with Vault.
UserAgent string
// MetricsSignifier is the first argument we will give to
// metrics.IncrCounter, signifying what the name of the application is
MetricsSignifier string
EnableReauthOnNewCredentials bool
EnableTemplateTokenCh bool
EnableExecTokenCh bool
ExitOnError bool
}
func NewAuthHandler(conf *AuthHandlerConfig) *AuthHandler {
ah := &AuthHandler{
// This is buffered so that if we try to output after the sink server
// has been shut down, during agent/proxy shutdown, we won't block
OutputCh: make(chan string, 1),
TemplateTokenCh: make(chan string, 1),
ExecTokenCh: make(chan string, 1),
token: conf.Token,
logger: conf.Logger,
client: conf.Client,
random: rand.New(rand.NewSource(int64(time.Now().Nanosecond()))),
wrapTTL: conf.WrapTTL,
minBackoff: conf.MinBackoff,
maxBackoff: conf.MaxBackoff,
enableReauthOnNewCredentials: conf.EnableReauthOnNewCredentials,
enableTemplateTokenCh: conf.EnableTemplateTokenCh,
enableExecTokenCh: conf.EnableExecTokenCh,
exitOnError: conf.ExitOnError,
userAgent: conf.UserAgent,
metricsSignifier: conf.MetricsSignifier,
}
return ah
}
func backoff(ctx context.Context, backoff *autoAuthBackoff) bool {
if backoff.exitOnErr {
return false
}
select {
case <-time.After(backoff.current):
case <-ctx.Done():
}
// Increase exponential backoff for the next time if we don't
// successfully auth/renew/etc.
backoff.next()
return true
}
func (ah *AuthHandler) Run(ctx context.Context, am AuthMethod) error {
if am == nil {
return errors.New("auth handler: nil auth method")
}
if ah.minBackoff <= 0 {
ah.minBackoff = defaultMinBackoff
}
backoffCfg := newAutoAuthBackoff(ah.minBackoff, ah.maxBackoff, ah.exitOnError)
if backoffCfg.min >= backoffCfg.max {
return errors.New("auth handler: min_backoff cannot be greater than max_backoff")
}
ah.logger.Info("starting auth handler")
defer func() {
am.Shutdown()
close(ah.OutputCh)
close(ah.TemplateTokenCh)
close(ah.ExecTokenCh)
ah.logger.Info("auth handler stopped")
}()
credCh := am.NewCreds()
if !ah.enableReauthOnNewCredentials {
realCredCh := credCh
credCh = nil
if realCredCh != nil {
go func() {
for {
select {
case <-ctx.Done():
return
case <-realCredCh:
}
}
}()
}
}
if credCh == nil {
credCh = make(chan struct{})
}
if ah.client != nil {
headers := ah.client.Headers()
if headers == nil {
headers = make(http.Header)
}
headers.Set("User-Agent", ah.userAgent)
ah.client.SetHeaders(headers)
}
var watcher *api.LifetimeWatcher
first := true
for {
select {
case <-ctx.Done():
return nil
default:
}
var clientToUse *api.Client
var err error
var path string
var data map[string]interface{}
var header http.Header
var isTokenFileMethod bool
switch am.(type) {
case AuthMethodWithClient:
clientToUse, err = am.(AuthMethodWithClient).AuthClient(ah.client)
if err != nil {
ah.logger.Error("error creating client for authentication call", "error", err, "backoff", backoff)
metrics.IncrCounter([]string{ah.metricsSignifier, "auth", "failure"}, 1)
if backoff(ctx, backoffCfg) {
continue
}
return err
}
default:
clientToUse = ah.client
}
// Disable retry on the client to ensure our backoffOrQuit function is
// the only source of retry/backoff.
clientToUse.SetMaxRetries(0)
var secret *api.Secret = new(api.Secret)
if first && ah.token != "" {
ah.logger.Debug("using preloaded token")
first = false
ah.logger.Debug("lookup-self with preloaded token")
clientToUse.SetToken(ah.token)
secret, err = clientToUse.Auth().Token().LookupSelfWithContext(ctx)
if err != nil {
ah.logger.Error("could not look up token", "err", err, "backoff", backoffCfg)
metrics.IncrCounter([]string{ah.metricsSignifier, "auth", "failure"}, 1)
if backoff(ctx, backoffCfg) {
continue
}
return err
}
duration, _ := secret.Data["ttl"].(json.Number).Int64()
secret.Auth = &api.SecretAuth{
ClientToken: secret.Data["id"].(string),
LeaseDuration: int(duration),
Renewable: secret.Data["renewable"].(bool),
}
} else {
ah.logger.Info("authenticating")
path, header, data, err = am.Authenticate(ctx, ah.client)
if err != nil {
ah.logger.Error("error getting path or data from method", "error", err, "backoff", backoffCfg)
metrics.IncrCounter([]string{ah.metricsSignifier, "auth", "failure"}, 1)
if backoff(ctx, backoffCfg) {
continue
}
return err
}
}
if ah.wrapTTL > 0 {
wrapClient, err := clientToUse.Clone()
if err != nil {
ah.logger.Error("error creating client for wrapped call", "error", err, "backoff", backoffCfg)
metrics.IncrCounter([]string{ah.metricsSignifier, "auth", "failure"}, 1)
if backoff(ctx, backoffCfg) {
continue
}
return err
}
wrapClient.SetWrappingLookupFunc(func(string, string) string {
return ah.wrapTTL.String()
})
clientToUse = wrapClient
}
for key, values := range header {
for _, value := range values {
clientToUse.AddHeader(key, value)
}
}
// This should only happen if there's no preloaded token (regular auto-auth login)
// or if a preloaded token has expired and is now switching to auto-auth.
if secret.Auth == nil {
isTokenFileMethod = path == "auth/token/lookup-self"
if isTokenFileMethod {
token, _ := data["token"].(string)
lookupSelfClient, err := clientToUse.Clone()
if err != nil {
ah.logger.Error("failed to clone client to perform token lookup")
return err
}
lookupSelfClient.SetToken(token)
secret, err = lookupSelfClient.Auth().Token().LookupSelf()
} else {
secret, err = clientToUse.Logical().WriteWithContext(ctx, path, data)
}
// Check errors/sanity
if err != nil {
ah.logger.Error("error authenticating", "error", err, "backoff", backoffCfg)
metrics.IncrCounter([]string{ah.metricsSignifier, "auth", "failure"}, 1)
if backoff(ctx, backoffCfg) {
continue
}
return err
}
}
var leaseDuration int
switch {
case ah.wrapTTL > 0:
if secret.WrapInfo == nil {
ah.logger.Error("authentication returned nil wrap info", "backoff", backoffCfg)
metrics.IncrCounter([]string{ah.metricsSignifier, "auth", "failure"}, 1)
if backoff(ctx, backoffCfg) {
continue
}
return err
}
if secret.WrapInfo.Token == "" {
ah.logger.Error("authentication returned empty wrapped client token", "backoff", backoffCfg)
metrics.IncrCounter([]string{ah.metricsSignifier, "auth", "failure"}, 1)
if backoff(ctx, backoffCfg) {
continue
}
return err
}
wrappedResp, err := jsonutil.EncodeJSON(secret.WrapInfo)
if err != nil {
ah.logger.Error("failed to encode wrapinfo", "error", err, "backoff", backoffCfg)
metrics.IncrCounter([]string{ah.metricsSignifier, "auth", "failure"}, 1)
if backoff(ctx, backoffCfg) {
continue
}
return err
}
ah.logger.Info("authentication successful, sending wrapped token to sinks and pausing")
ah.OutputCh <- string(wrappedResp)
if ah.enableTemplateTokenCh {
ah.TemplateTokenCh <- string(wrappedResp)
}
if ah.enableExecTokenCh {
ah.ExecTokenCh <- string(wrappedResp)
}
am.CredSuccess()
backoffCfg.reset()
select {
case <-ctx.Done():
ah.logger.Info("shutdown triggered")
continue
case <-credCh:
ah.logger.Info("auth method found new credentials, re-authenticating")
continue
}
default:
// We handle the token_file method specially, as it's the only
// auth method that isn't actually authenticating, i.e. the secret
// returned does not have an Auth struct attached
isTokenFileMethod := path == "auth/token/lookup-self"
if isTokenFileMethod {
// We still check the response of the request to ensure the token is valid
// i.e. if the token is invalid, we will fail in the authentication step
if secret == nil || secret.Data == nil {
ah.logger.Error("token file validation failed, token may be invalid", "backoff", backoffCfg)
metrics.IncrCounter([]string{ah.metricsSignifier, "auth", "failure"}, 1)
if backoff(ctx, backoffCfg) {
continue
}
return err
}
token, ok := secret.Data["id"].(string)
if !ok || token == "" {
ah.logger.Error("token file validation returned empty client token", "backoff", backoffCfg)
metrics.IncrCounter([]string{ah.metricsSignifier, "auth", "failure"}, 1)
if backoff(ctx, backoffCfg) {
continue
}
return err
}
duration, _ := secret.Data["ttl"].(json.Number).Int64()
leaseDuration = int(duration)
renewable, _ := secret.Data["renewable"].(bool)
secret.Auth = &api.SecretAuth{
ClientToken: token,
LeaseDuration: int(duration),
Renewable: renewable,
}
ah.logger.Info("authentication successful, sending token to sinks")
ah.OutputCh <- token
if ah.enableTemplateTokenCh {
ah.TemplateTokenCh <- token
}
if ah.enableExecTokenCh {
ah.ExecTokenCh <- token
}
tokenType := secret.Data["type"].(string)
if tokenType == "batch" {
ah.logger.Info("note that this token type is batch, and batch tokens cannot be renewed", "ttl", leaseDuration)
}
} else {
if secret == nil || secret.Auth == nil {
ah.logger.Error("authentication returned nil auth info", "backoff", backoffCfg)
metrics.IncrCounter([]string{ah.metricsSignifier, "auth", "failure"}, 1)
if backoff(ctx, backoffCfg) {
continue
}
return err
}
if secret.Auth.ClientToken == "" {
ah.logger.Error("authentication returned empty client token", "backoff", backoffCfg)
metrics.IncrCounter([]string{ah.metricsSignifier, "auth", "failure"}, 1)
if backoff(ctx, backoffCfg) {
continue
}
return err
}
leaseDuration = secret.LeaseDuration
ah.logger.Info("authentication successful, sending token to sinks")
ah.OutputCh <- secret.Auth.ClientToken
if ah.enableTemplateTokenCh {
ah.TemplateTokenCh <- secret.Auth.ClientToken
}
if ah.enableExecTokenCh {
ah.ExecTokenCh <- secret.Auth.ClientToken
}
}
am.CredSuccess()
backoffCfg.reset()
}
if watcher != nil {
watcher.Stop()
}
watcher, err = clientToUse.NewLifetimeWatcher(&api.LifetimeWatcherInput{
Secret: secret,
})
if err != nil {
ah.logger.Error("error creating lifetime watcher", "error", err, "backoff", backoffCfg)
metrics.IncrCounter([]string{ah.metricsSignifier, "auth", "failure"}, 1)
if backoff(ctx, backoffCfg) {
continue
}
return err
}
metrics.IncrCounter([]string{ah.metricsSignifier, "auth", "success"}, 1)
// We don't want to trigger the renewal process for tokens with
// unlimited TTL, such as the root token.
if leaseDuration == 0 && isTokenFileMethod {
ah.logger.Info("not starting token renewal process, as token has unlimited TTL")
} else {
ah.logger.Info("starting renewal process")
go watcher.Renew()
}
LifetimeWatcherLoop:
for {
select {
case <-ctx.Done():
ah.logger.Info("shutdown triggered, stopping lifetime watcher")
watcher.Stop()
break LifetimeWatcherLoop
case err := <-watcher.DoneCh():
ah.logger.Info("lifetime watcher done channel triggered")
if err != nil {
metrics.IncrCounter([]string{ah.metricsSignifier, "auth", "failure"}, 1)
ah.logger.Error("error renewing token", "error", err)
}
break LifetimeWatcherLoop
case <-watcher.RenewCh():
metrics.IncrCounter([]string{ah.metricsSignifier, "auth", "success"}, 1)
ah.logger.Info("renewed auth token")
case <-credCh:
ah.logger.Info("auth method found new credentials, re-authenticating")
break LifetimeWatcherLoop
}
}
}
}
// autoAuthBackoff tracks exponential backoff state.
type autoAuthBackoff struct {
min time.Duration
max time.Duration
current time.Duration
exitOnErr bool
}
func newAutoAuthBackoff(min, max time.Duration, exitErr bool) *autoAuthBackoff {
if max <= 0 {
max = defaultMaxBackoff
}
if min <= 0 {
min = defaultMinBackoff
}
return &autoAuthBackoff{
current: min,
max: max,
min: min,
exitOnErr: exitErr,
}
}
// next determines the next backoff duration that is roughly twice
// the current value, capped to a max value, with a measure of randomness.
func (b *autoAuthBackoff) next() {
maxBackoff := 2 * b.current
if maxBackoff > b.max {
maxBackoff = b.max
}
// Trim a random amount (0-25%) off the doubled duration
trim := rand.Int63n(int64(maxBackoff) / 4)
b.current = maxBackoff - time.Duration(trim)
}
func (b *autoAuthBackoff) reset() {
b.current = b.min
}
func (b autoAuthBackoff) String() string {
return b.current.Truncate(10 * time.Millisecond).String()
}