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sessionmanager.go
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sessionmanager.go
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package session
import (
"context"
"encoding/json"
"errors"
"fmt"
"math"
"math/rand"
"net"
"net/http"
"os"
"strings"
"time"
oidc "github.com/coreos/go-oidc"
"github.com/dgrijalva/jwt-go/v4"
"github.com/google/uuid"
log "github.com/sirupsen/logrus"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/status"
"github.com/argoproj/argo-cd/v2/common"
"github.com/argoproj/argo-cd/v2/pkg/client/listers/application/v1alpha1"
"github.com/argoproj/argo-cd/v2/server/rbacpolicy"
"github.com/argoproj/argo-cd/v2/util/cache/appstate"
"github.com/argoproj/argo-cd/v2/util/dex"
"github.com/argoproj/argo-cd/v2/util/env"
httputil "github.com/argoproj/argo-cd/v2/util/http"
jwtutil "github.com/argoproj/argo-cd/v2/util/jwt"
oidcutil "github.com/argoproj/argo-cd/v2/util/oidc"
passwordutil "github.com/argoproj/argo-cd/v2/util/password"
"github.com/argoproj/argo-cd/v2/util/settings"
)
// SessionManager generates and validates JWT tokens for login sessions.
type SessionManager struct {
settingsMgr *settings.SettingsManager
projectsLister v1alpha1.AppProjectNamespaceLister
client *http.Client
prov oidcutil.Provider
storage UserStateStorage
sleep func(d time.Duration)
verificationDelayNoiseEnabled bool
}
// LoginAttempts is a timestamped counter for failed login attempts
type LoginAttempts struct {
// Time of the last failed login
LastFailed time.Time `json:"lastFailed"`
// Number of consecutive login failures
FailCount int `json:"failCount"`
}
const (
// SessionManagerClaimsIssuer fills the "iss" field of the token.
SessionManagerClaimsIssuer = "argocd"
AuthErrorCtxKey = "auth-error"
// invalidLoginError, for security purposes, doesn't say whether the username or password was invalid. This does not mitigate the potential for timing attacks to determine which is which.
invalidLoginError = "Invalid username or password"
blankPasswordError = "Blank passwords are not allowed"
accountDisabled = "Account %s is disabled"
usernameTooLongError = "Username is too long (%d bytes max)"
userDoesNotHaveCapability = "Account %s does not have %s capability"
autoRegenerateTokenDuration = time.Minute * 5
)
const (
// Maximum length of username, too keep the cache's memory signature low
maxUsernameLength = 32
// The default maximum session cache size
defaultMaxCacheSize = 1000
// The default number of maximum login failures before delay kicks in
defaultMaxLoginFailures = 5
// The default time in seconds for the failure window
defaultFailureWindow = 300
// The password verification delay max
verificationDelayNoiseMin = 500 * time.Millisecond
// The password verification delay max
verificationDelayNoiseMax = 1000 * time.Millisecond
// environment variables to control rate limiter behaviour:
// Max number of login failures before login delay kicks in
envLoginMaxFailCount = "ARGOCD_SESSION_FAILURE_MAX_FAIL_COUNT"
// Number of maximum seconds the login is allowed to delay for. Default: 300 (5 minutes).
envLoginFailureWindowSeconds = "ARGOCD_SESSION_FAILURE_WINDOW_SECONDS"
// Max number of stored usernames
envLoginMaxCacheSize = "ARGOCD_SESSION_MAX_CACHE_SIZE"
)
var (
InvalidLoginErr = status.Errorf(codes.Unauthenticated, invalidLoginError)
)
// Returns the maximum cache size as number of entries
func getMaximumCacheSize() int {
return env.ParseNumFromEnv(envLoginMaxCacheSize, defaultMaxCacheSize, 1, math.MaxInt32)
}
// Returns the maximum number of login failures before login delay kicks in
func getMaxLoginFailures() int {
return env.ParseNumFromEnv(envLoginMaxFailCount, defaultMaxLoginFailures, 1, math.MaxInt32)
}
// Returns the number of maximum seconds the login is allowed to delay for
func getLoginFailureWindow() time.Duration {
return time.Duration(env.ParseNumFromEnv(envLoginFailureWindowSeconds, defaultFailureWindow, 0, math.MaxInt32))
}
// NewSessionManager creates a new session manager from Argo CD settings
func NewSessionManager(settingsMgr *settings.SettingsManager, projectsLister v1alpha1.AppProjectNamespaceLister, dexServerAddr string, storage UserStateStorage) *SessionManager {
s := SessionManager{
settingsMgr: settingsMgr,
storage: storage,
sleep: time.Sleep,
projectsLister: projectsLister,
verificationDelayNoiseEnabled: true,
}
settings, err := settingsMgr.GetSettings()
if err != nil {
panic(err)
}
tlsConfig := settings.TLSConfig()
if tlsConfig != nil {
tlsConfig.InsecureSkipVerify = true
}
s.client = &http.Client{
Transport: &http.Transport{
TLSClientConfig: tlsConfig,
Proxy: http.ProxyFromEnvironment,
Dial: (&net.Dialer{
Timeout: 30 * time.Second,
KeepAlive: 30 * time.Second,
}).Dial,
TLSHandshakeTimeout: 10 * time.Second,
ExpectContinueTimeout: 1 * time.Second,
},
}
if settings.DexConfig != "" {
s.client.Transport = dex.NewDexRewriteURLRoundTripper(dexServerAddr, s.client.Transport)
}
if os.Getenv(common.EnvVarSSODebug) == "1" {
s.client.Transport = httputil.DebugTransport{T: s.client.Transport}
}
return &s
}
// Create creates a new token for a given subject (user) and returns it as a string.
// Passing a value of `0` for secondsBeforeExpiry creates a token that never expires.
// The id parameter holds an optional unique JWT token identifier and stored as a standard claim "jti" in the JWT token.
func (mgr *SessionManager) Create(subject string, secondsBeforeExpiry int64, id string) (string, error) {
// Create a new token object, specifying signing method and the claims
// you would like it to contain.
now := time.Now().UTC()
claims := jwt.StandardClaims{
IssuedAt: jwt.At(now),
Issuer: SessionManagerClaimsIssuer,
NotBefore: jwt.At(now),
Subject: subject,
ID: id,
}
if secondsBeforeExpiry > 0 {
expires := now.Add(time.Duration(secondsBeforeExpiry) * time.Second)
claims.ExpiresAt = jwt.At(expires)
}
return mgr.signClaims(claims)
}
type standardClaims struct {
Audience jwt.ClaimStrings `json:"aud,omitempty"`
ExpiresAt int64 `json:"exp,omitempty"`
ID string `json:"jti,omitempty"`
IssuedAt int64 `json:"iat,omitempty"`
Issuer string `json:"iss,omitempty"`
NotBefore int64 `json:"nbf,omitempty"`
Subject string `json:"sub,omitempty"`
}
func unixTimeOrZero(t *jwt.Time) int64 {
if t == nil {
return 0
}
return t.Unix()
}
func (mgr *SessionManager) signClaims(claims jwt.Claims) (string, error) {
// log.Infof("Issuing claims: %v", claims)
token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
settings, err := mgr.settingsMgr.GetSettings()
if err != nil {
return "", err
}
// workaround for https://github.com/argoproj/argo-cd/issues/5217
// According to https://tools.ietf.org/html/rfc7519#section-4.1.6 "iat" and other time fields must contain
// number of seconds from 1970-01-01T00:00:00Z UTC until the specified UTC date/time.
// The https://github.com/dgrijalva/jwt-go marshals time as non integer.
return token.SignedString(settings.ServerSignature, jwt.WithMarshaller(func(ctx jwt.CodingContext, v interface{}) ([]byte, error) {
if std, ok := v.(jwt.StandardClaims); ok {
return json.Marshal(standardClaims{
Audience: std.Audience,
ExpiresAt: unixTimeOrZero(std.ExpiresAt),
ID: std.ID,
IssuedAt: unixTimeOrZero(std.IssuedAt),
Issuer: std.Issuer,
NotBefore: unixTimeOrZero(std.NotBefore),
Subject: std.Subject,
})
}
return json.Marshal(v)
}))
}
// GetSubjectAccountAndCapability analyzes Argo CD account token subject and extract account name
// and the capability it was generated for (default capability is API Key).
func GetSubjectAccountAndCapability(subject string) (string, settings.AccountCapability) {
capability := settings.AccountCapabilityApiKey
if parts := strings.Split(subject, ":"); len(parts) > 1 {
subject = parts[0]
switch parts[1] {
case string(settings.AccountCapabilityLogin):
capability = settings.AccountCapabilityLogin
case string(settings.AccountCapabilityApiKey):
capability = settings.AccountCapabilityApiKey
}
}
return subject, capability
}
// Parse tries to parse the provided string and returns the token claims for local login.
func (mgr *SessionManager) Parse(tokenString string) (jwt.Claims, string, error) {
// Parse takes the token string and a function for looking up the key. The latter is especially
// useful if you use multiple keys for your application. The standard is to use 'kid' in the
// head of the token to identify which key to use, but the parsed token (head and claims) is provided
// to the callback, providing flexibility.
var claims jwt.MapClaims
argoCDSettings, err := mgr.settingsMgr.GetSettings()
if err != nil {
return nil, "", err
}
token, err := jwt.ParseWithClaims(tokenString, &claims, func(token *jwt.Token) (interface{}, error) {
// Don't forget to validate the alg is what you expect:
if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
}
return argoCDSettings.ServerSignature, nil
})
if err != nil {
return nil, "", err
}
issuedAt, err := jwtutil.IssuedAtTime(claims)
if err != nil {
return nil, "", err
}
subject := jwtutil.StringField(claims, "sub")
id := jwtutil.StringField(claims, "jti")
if projName, role, ok := rbacpolicy.GetProjectRoleFromSubject(subject); ok {
proj, err := mgr.projectsLister.Get(projName)
if err != nil {
return nil, "", err
}
_, _, err = proj.GetJWTToken(role, issuedAt.Unix(), id)
if err != nil {
return nil, "", err
}
return token.Claims, "", nil
}
subject, capability := GetSubjectAccountAndCapability(subject)
claims["sub"] = subject
account, err := mgr.settingsMgr.GetAccount(subject)
if err != nil {
return nil, "", err
}
if !account.Enabled {
return nil, "", fmt.Errorf("account %s is disabled", subject)
}
if !account.HasCapability(capability) {
return nil, "", fmt.Errorf("account %s does not have '%s' capability", subject, capability)
}
if id == "" || mgr.storage.IsTokenRevoked(id) {
return nil, "", errors.New("token is revoked, please re-login")
} else if capability == settings.AccountCapabilityApiKey && account.TokenIndex(id) == -1 {
return nil, "", fmt.Errorf("account %s does not have token with id %s", subject, id)
}
if account.PasswordMtime != nil && issuedAt.Before(*account.PasswordMtime) {
return nil, "", fmt.Errorf("account password has changed since token issued")
}
newToken := ""
if exp, err := jwtutil.ExpirationTime(claims); err == nil {
tokenExpDuration := exp.Sub(issuedAt)
remainingDuration := time.Until(exp)
if remainingDuration < autoRegenerateTokenDuration && capability == settings.AccountCapabilityLogin {
if uniqueId, err := uuid.NewRandom(); err == nil {
if val, err := mgr.Create(fmt.Sprintf("%s:%s", subject, settings.AccountCapabilityLogin), int64(tokenExpDuration.Seconds()), uniqueId.String()); err == nil {
newToken = val
}
}
}
}
return token.Claims, newToken, nil
}
// GetLoginFailures retrieves the login failure information from the cache
func (mgr *SessionManager) GetLoginFailures() map[string]LoginAttempts {
// Get failures from the cache
var failures map[string]LoginAttempts
err := mgr.storage.GetLoginAttempts(&failures)
if err != nil {
if err != appstate.ErrCacheMiss {
log.Errorf("Could not retrieve login attempts: %v", err)
}
failures = make(map[string]LoginAttempts)
}
return failures
}
func expireOldFailedAttempts(maxAge time.Duration, failures *map[string]LoginAttempts) int {
expiredCount := 0
for key, attempt := range *failures {
if time.Since(attempt.LastFailed) > maxAge*time.Second {
expiredCount += 1
delete(*failures, key)
}
}
return expiredCount
}
// Updates the failure count for a given username. If failed is true, increases the counter. Otherwise, sets counter back to 0.
func (mgr *SessionManager) updateFailureCount(username string, failed bool) {
failures := mgr.GetLoginFailures()
// Expire old entries in the cache if we have a failure window defined.
if window := getLoginFailureWindow(); window > 0 {
count := expireOldFailedAttempts(window, &failures)
if count > 0 {
log.Infof("Expired %d entries from session cache due to max age reached", count)
}
}
// If we exceed a certain cache size, we need to remove random entries to
// prevent overbloating the cache with fake entries, as this could lead to
// memory exhaustion and ultimately in a DoS. We remove a single entry to
// replace it with the new one.
//
// Chances are that we remove the one that is under active attack, but this
// chance is low (1:cache_size)
if failed && len(failures) >= getMaximumCacheSize() {
log.Warnf("Session cache size exceeds %d entries, removing random entry", getMaximumCacheSize())
idx := rand.Intn(len(failures) - 1)
var rmUser string
i := 0
for key := range failures {
if i == idx {
rmUser = key
delete(failures, key)
break
}
i++
}
log.Infof("Deleted entry for user %s from cache", rmUser)
}
attempt, ok := failures[username]
if !ok {
attempt = LoginAttempts{FailCount: 0}
}
// On login failure, increase fail count and update last failed timestamp.
// On login success, remove the entry from the cache.
if failed {
attempt.FailCount += 1
attempt.LastFailed = time.Now()
failures[username] = attempt
log.Warnf("User %s failed login %d time(s)", username, attempt.FailCount)
} else {
if attempt.FailCount > 0 {
// Forget username for cache size enforcement, since entry in cache was deleted
delete(failures, username)
}
}
err := mgr.storage.SetLoginAttempts(failures)
if err != nil {
log.Errorf("Could not update login attempts: %v", err)
}
}
// Get the current login failure attempts for given username
func (mgr *SessionManager) getFailureCount(username string) LoginAttempts {
failures := mgr.GetLoginFailures()
attempt, ok := failures[username]
if !ok {
attempt = LoginAttempts{FailCount: 0}
}
return attempt
}
// Calculate a login delay for the given login attempt
func (mgr *SessionManager) exceededFailedLoginAttempts(attempt LoginAttempts) bool {
maxFails := getMaxLoginFailures()
failureWindow := getLoginFailureWindow()
// Whether we are in the failure window for given attempt
inWindow := func() bool {
if failureWindow == 0 || time.Since(attempt.LastFailed).Seconds() <= float64(failureWindow) {
return true
}
return false
}
// If we reached max failed attempts within failure window, we need to calc the delay
if attempt.FailCount >= maxFails && inWindow() {
return true
}
return false
}
// VerifyUsernamePassword verifies if a username/password combo is correct
func (mgr *SessionManager) VerifyUsernamePassword(username string, password string) error {
if password == "" {
return status.Errorf(codes.Unauthenticated, blankPasswordError)
}
// Enforce maximum length of username on local accounts
if len(username) > maxUsernameLength {
return status.Errorf(codes.InvalidArgument, usernameTooLongError, maxUsernameLength)
}
start := time.Now()
if mgr.verificationDelayNoiseEnabled {
defer func() {
// introduces random delay to protect from timing-based user enumeration attack
delayNanoseconds := verificationDelayNoiseMin.Nanoseconds() +
int64(rand.Intn(int(verificationDelayNoiseMax.Nanoseconds()-verificationDelayNoiseMin.Nanoseconds())))
// take into account amount of time spent since the request start
delayNanoseconds = delayNanoseconds - time.Since(start).Nanoseconds()
if delayNanoseconds > 0 {
mgr.sleep(time.Duration(delayNanoseconds))
}
}()
}
attempt := mgr.getFailureCount(username)
if mgr.exceededFailedLoginAttempts(attempt) {
log.Warnf("User %s had too many failed logins (%d)", username, attempt.FailCount)
return InvalidLoginErr
}
account, err := mgr.settingsMgr.GetAccount(username)
if err != nil {
if errStatus, ok := status.FromError(err); ok && errStatus.Code() == codes.NotFound {
mgr.updateFailureCount(username, true)
err = InvalidLoginErr
}
// to prevent time-based user enumeration, we must perform a password
// hash cycle to keep response time consistent (if the function were
// to continue and not return here)
_, _ = passwordutil.HashPassword("for_consistent_response_time")
return err
}
valid, _ := passwordutil.VerifyPassword(password, account.PasswordHash)
if !valid {
mgr.updateFailureCount(username, true)
return InvalidLoginErr
}
if !account.Enabled {
return status.Errorf(codes.Unauthenticated, accountDisabled, username)
}
if !account.HasCapability(settings.AccountCapabilityLogin) {
return status.Errorf(codes.Unauthenticated, userDoesNotHaveCapability, username, settings.AccountCapabilityLogin)
}
mgr.updateFailureCount(username, false)
return nil
}
// VerifyToken verifies if a token is correct. Tokens can be issued either from us or by an IDP.
// We choose how to verify based on the issuer.
func (mgr *SessionManager) VerifyToken(tokenString string) (jwt.Claims, string, error) {
parser := &jwt.Parser{
ValidationHelper: jwt.NewValidationHelper(jwt.WithoutClaimsValidation(), jwt.WithoutAudienceValidation()),
}
var claims jwt.StandardClaims
_, _, err := parser.ParseUnverified(tokenString, &claims)
if err != nil {
return nil, "", err
}
switch claims.Issuer {
case SessionManagerClaimsIssuer:
// Argo CD signed token
return mgr.Parse(tokenString)
default:
// IDP signed token
prov, err := mgr.provider()
if err != nil {
return nil, "", err
}
// Token must be verified for at least one audience
// TODO(jannfis): Is this the right way? Shouldn't we know our audience and only validate for the correct one?
var idToken *oidc.IDToken
for _, aud := range claims.Audience {
idToken, err = prov.Verify(aud, tokenString)
if err == nil {
break
}
}
// The token verification has failed. If the token has expired, we will
// return a dummy claims only containing a value for the issuer, so the
// UI can handle expired tokens appropriately.
if err != nil {
if strings.HasPrefix(err.Error(), "oidc: token is expired") {
claims = jwt.StandardClaims{
Issuer: "sso",
}
return claims, "", err
}
return nil, "", err
}
if idToken == nil {
return nil, "", fmt.Errorf("no audience found in the token")
}
var claims jwt.MapClaims
err = idToken.Claims(&claims)
if err != nil {
return nil, "", err
}
return claims, "", nil
}
}
func (mgr *SessionManager) provider() (oidcutil.Provider, error) {
if mgr.prov != nil {
return mgr.prov, nil
}
settings, err := mgr.settingsMgr.GetSettings()
if err != nil {
return nil, err
}
if !settings.IsSSOConfigured() {
return nil, fmt.Errorf("SSO is not configured")
}
mgr.prov = oidcutil.NewOIDCProvider(settings.IssuerURL(), mgr.client)
return mgr.prov, nil
}
func (mgr *SessionManager) RevokeToken(ctx context.Context, id string, expiringAt time.Duration) error {
return mgr.storage.RevokeToken(ctx, id, expiringAt)
}
func LoggedIn(ctx context.Context) bool {
return Sub(ctx) != "" && ctx.Value(AuthErrorCtxKey) == nil
}
// Username is a helper to extract a human readable username from a context
func Username(ctx context.Context) string {
mapClaims, ok := mapClaims(ctx)
if !ok {
return ""
}
switch jwtutil.StringField(mapClaims, "iss") {
case SessionManagerClaimsIssuer:
return jwtutil.StringField(mapClaims, "sub")
default:
return jwtutil.StringField(mapClaims, "email")
}
}
func Iss(ctx context.Context) string {
mapClaims, ok := mapClaims(ctx)
if !ok {
return ""
}
return jwtutil.StringField(mapClaims, "iss")
}
func Iat(ctx context.Context) (time.Time, error) {
mapClaims, ok := mapClaims(ctx)
if !ok {
return time.Time{}, errors.New("unable to extract token claims")
}
return jwtutil.IssuedAtTime(mapClaims)
}
func Sub(ctx context.Context) string {
mapClaims, ok := mapClaims(ctx)
if !ok {
return ""
}
return jwtutil.StringField(mapClaims, "sub")
}
func Groups(ctx context.Context, scopes []string) []string {
mapClaims, ok := mapClaims(ctx)
if !ok {
return nil
}
return jwtutil.GetGroups(mapClaims, scopes)
}
func mapClaims(ctx context.Context) (jwt.MapClaims, bool) {
claims, ok := ctx.Value("claims").(jwt.Claims)
if !ok {
return nil, false
}
mapClaims, err := jwtutil.MapClaims(claims)
if err != nil {
return nil, false
}
return mapClaims, true
}