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methods.go
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methods.go
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/*
* Teleport
* Copyright (C) 2023 Gravitational, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package auth
import (
"bytes"
"context"
"errors"
"net"
"time"
"github.com/gravitational/trace"
"golang.org/x/crypto/ssh"
"github.com/gravitational/teleport/api/client/proto"
"github.com/gravitational/teleport/api/constants"
mfav1 "github.com/gravitational/teleport/api/gen/proto/go/teleport/mfa/v1"
"github.com/gravitational/teleport/api/types"
apievents "github.com/gravitational/teleport/api/types/events"
"github.com/gravitational/teleport/api/utils/keys"
wantypes "github.com/gravitational/teleport/lib/auth/webauthntypes"
"github.com/gravitational/teleport/lib/authz"
"github.com/gravitational/teleport/lib/defaults"
"github.com/gravitational/teleport/lib/events"
"github.com/gravitational/teleport/lib/services"
"github.com/gravitational/teleport/lib/utils"
)
const (
// maxUserAgentLen is the maximum length of a user agent that will be logged.
// There is no current consensus on what the maximum length of a User-Agent
// should be and there were reports of extremely large UAs especially from
// older versions of IE. 2048 was picked because it still allowed for very
// large UAs but keeps from causing logging issues. For reference Nginx
// defaults to 4k or 8k header size limits for ALL headers so 2k seems more
// than sufficient.
maxUserAgentLen = 2048
)
// AuthenticateUserRequest is a request to authenticate interactive user
type AuthenticateUserRequest struct {
// Username is a username
Username string `json:"username"`
// PublicKey is a public key in ssh authorized_keys format
PublicKey []byte `json:"public_key"`
// Pass is a password used in local authentication schemes
Pass *PassCreds `json:"pass,omitempty"`
// Webauthn is a signed credential assertion, used in MFA authentication
Webauthn *wantypes.CredentialAssertionResponse `json:"webauthn,omitempty"`
// OTP is a password and second factor, used for MFA authentication
OTP *OTPCreds `json:"otp,omitempty"`
// Session is a web session credential used to authenticate web sessions
Session *SessionCreds `json:"session,omitempty"`
// ClientMetadata includes forwarded information about a client
ClientMetadata *ForwardedClientMetadata `json:"client_metadata,omitempty"`
// HeadlessAuthenticationID is the ID for a headless authentication resource.
HeadlessAuthenticationID string `json:"headless_authentication_id"`
}
// ForwardedClientMetadata can be used by the proxy web API to forward information about
// the client to the auth service.
type ForwardedClientMetadata struct {
UserAgent string `json:"user_agent,omitempty"`
// RemoteAddr is the IP address of the end user. This IP address is derived
// either from a direct client connection, or from a PROXY protocol header
// if the connection is forwarded through a load balancer.
RemoteAddr string `json:"remote_addr,omitempty"`
}
// CheckAndSetDefaults checks and sets defaults
func (a *AuthenticateUserRequest) CheckAndSetDefaults() error {
switch {
case a.Username == "" && a.Webauthn != nil: // OK, passwordless.
case a.Username == "":
return trace.BadParameter("missing parameter 'username'")
case a.Pass == nil && a.Webauthn == nil && a.OTP == nil && a.Session == nil && a.HeadlessAuthenticationID == "":
return trace.BadParameter("at least one authentication method is required")
}
return nil
}
// PassCreds is a password credential
type PassCreds struct {
// Password is a user password
Password []byte `json:"password"`
}
// OTPCreds is a two-factor authentication credentials
type OTPCreds struct {
// Password is a user password
Password []byte `json:"password"`
// Token is a user second factor token
Token string `json:"token"`
}
// SessionCreds is a web session credentials
type SessionCreds struct {
// ID is a web session id
ID string `json:"id"`
}
// AuthenticateUser authenticates user based on the request type.
// Returns the username of the authenticated user.
func (a *Server) AuthenticateUser(ctx context.Context, req AuthenticateUserRequest) (services.UserState, services.AccessChecker, error) {
username := req.Username
verifyMFALocks, mfaDev, actualUsername, err := a.authenticateUser(ctx, req)
if err != nil {
// Log event after authentication failure
if err := a.emitAuthAuditEvent(ctx, authAuditProps{
username: req.Username,
clientMetadata: req.ClientMetadata,
authErr: err,
}); err != nil {
log.WithError(err).Warn("Failed to emit login event.")
}
return nil, nil, trace.Wrap(err)
}
switch {
case username != "" && actualUsername != "" && username != actualUsername:
log.Warnf("Authenticate user mismatch (%q vs %q). Using request user (%q)", username, actualUsername, username)
case username == "" && actualUsername != "":
log.Debugf("User %q authenticated via passwordless", actualUsername)
username = actualUsername
}
user, err := a.GetUser(ctx, username, false /* withSecrets */)
if err != nil {
return nil, nil, trace.Wrap(err)
}
// After we're sure that the user has been logged in successfully, we should call
// the registered login hooks. Login hooks can be registered by other processes to
// execute arbitrary operations after a successful login.
if err := a.CallLoginHooks(ctx, user); err != nil {
return nil, nil, trace.Wrap(err)
}
userState, err := a.GetUserOrLoginState(ctx, user.GetName())
if err != nil {
return nil, nil, trace.Wrap(err)
}
clusterName, err := a.GetClusterName()
if err != nil {
return nil, nil, trace.Wrap(err)
}
accessInfo := services.AccessInfoFromUserState(userState)
checker, err := services.NewAccessChecker(accessInfo, clusterName.GetClusterName(), a)
if err != nil {
return nil, nil, trace.Wrap(err)
}
// Verify if the MFA device is locked.
if err := verifyMFALocks(verifyMFADeviceLocksParams{
Checker: checker,
}); err != nil {
// Log MFA lock failure as an authn failure.
if err := a.emitAuthAuditEvent(ctx, authAuditProps{
username: req.Username,
clientMetadata: req.ClientMetadata,
mfaDevice: mfaDev,
checker: checker,
authErr: err,
}); err != nil {
log.WithError(err).Warn("Failed to emit login event.")
}
return nil, nil, trace.Wrap(err)
}
// Log event after authentication success
if err := a.emitAuthAuditEvent(ctx, authAuditProps{
username: username,
clientMetadata: req.ClientMetadata,
mfaDevice: mfaDev,
checker: checker,
}); err != nil {
log.WithError(err).Warn("Failed to emit login event.")
}
return userState, checker, trace.Wrap(err)
}
type authAuditProps struct {
username string
clientMetadata *ForwardedClientMetadata
mfaDevice *types.MFADevice
checker services.AccessChecker
authErr error
}
func (a *Server) emitAuthAuditEvent(ctx context.Context, props authAuditProps) error {
event := &apievents.UserLogin{
Metadata: apievents.Metadata{
Type: events.UserLoginEvent,
Code: events.UserLocalLoginCode,
},
Status: apievents.Status{
Success: true,
},
UserMetadata: apievents.UserMetadata{
User: props.username,
},
Method: events.LoginMethodLocal,
}
if props.authErr != nil {
event.Code = events.UserLocalLoginFailureCode
event.Status.Success = false
event.Status.Error = props.authErr.Error()
}
if props.clientMetadata != nil {
event.RemoteAddr = props.clientMetadata.RemoteAddr
event.UserAgent = trimUserAgent(props.clientMetadata.UserAgent)
}
if props.mfaDevice != nil {
m := mfaDeviceEventMetadata(props.mfaDevice)
event.MFADevice = &m
}
// Add required key policy to the event.
if props.checker != nil {
authPref, err := a.GetAuthPreference(ctx)
if err != nil {
return trace.Wrap(err)
}
privateKeyPolicy, err := props.checker.PrivateKeyPolicy(authPref.GetPrivateKeyPolicy())
if err != nil {
return trace.Wrap(err)
}
event.RequiredPrivateKeyPolicy = string(privateKeyPolicy)
}
return trace.Wrap(a.emitter.EmitAuditEvent(a.closeCtx, event))
}
var (
// authenticateHeadlessError is the generic error returned for failed headless
// authentication attempts.
authenticateHeadlessError = trace.AccessDenied("headless authentication failed")
// authenticateWebauthnError is the generic error returned for failed WebAuthn
// authentication attempts.
authenticateWebauthnError = trace.AccessDenied("invalid Webauthn response")
// invalidUserPassError is the error for when either the provided username or
// password is incorrect.
invalidUserPassError = trace.AccessDenied("invalid username or password")
// invalidUserpass2FError is the error for when either the provided username,
// password, or second factor is incorrect.
invalidUserPass2FError = trace.AccessDenied("invalid username, password or second factor")
)
// IsInvalidLocalCredentialError checks if an error resulted from an incorrect username,
// password, or second factor.
func IsInvalidLocalCredentialError(err error) bool {
return errors.Is(err, invalidUserPassError) || errors.Is(err, invalidUserPass2FError)
}
type verifyMFADeviceLocksParams struct {
// Checker used to verify locks.
// Optional, created via a [UserState] fetch if nil.
Checker services.AccessChecker
// ClusterLockingMode used to verify locks.
// Optional, acquired from [Server.GetAuthPreference] if nil.
ClusterLockingMode constants.LockingMode
}
// authenticateUser authenticates a user through various methods (password, MFA,
// passwordless)
//
// Returns a callback to verify MFA device locks, the MFA device used to
// authenticate (if applicable), and the authenticated user name.
//
// Callers MUST call the verifyLocks callback.
func (a *Server) authenticateUser(
ctx context.Context,
req AuthenticateUserRequest,
) (verifyLocks func(verifyMFADeviceLocksParams) error, mfaDev *types.MFADevice, user string, err error) {
mfaDev, user, err = a.authenticateUserInternal(ctx, req)
if err != nil || mfaDev == nil {
return func(verifyMFADeviceLocksParams) error { return nil }, mfaDev, user, trace.Wrap(err)
}
verifyLocks = func(p verifyMFADeviceLocksParams) error {
if p.Checker == nil {
userState, err := a.GetUserOrLoginState(ctx, user)
if err != nil {
return trace.Wrap(err)
}
accessInfo := services.AccessInfoFromUserState(userState)
clusterName, err := a.GetClusterName()
if err != nil {
return trace.Wrap(err)
}
checker, err := services.NewAccessChecker(accessInfo, clusterName.GetClusterName(), a)
if err != nil {
return trace.Wrap(err)
}
p.Checker = checker
}
if p.ClusterLockingMode == "" {
authPref, err := a.GetAuthPreference(ctx)
if err != nil {
return trace.Wrap(err)
}
p.ClusterLockingMode = authPref.GetLockingMode()
}
// The MFA device needs to be explicitly verified, as it won't be verified
// as part of certificate issuance in various scenarios (password change,
// non-session certificates, etc)
return a.verifyLocksForUserCerts(verifyLocksForUserCertsReq{
checker: p.Checker,
defaultMode: p.ClusterLockingMode,
username: user,
mfaVerified: mfaDev.Id,
})
}
return verifyLocks, mfaDev, user, nil
}
// Do not use this method directly, use authenticateUser instead.
func (a *Server) authenticateUserInternal(ctx context.Context, req AuthenticateUserRequest) (mfaDev *types.MFADevice, user string, err error) {
if err := req.CheckAndSetDefaults(); err != nil {
return nil, "", trace.Wrap(err)
}
user = req.Username
passwordless := user == ""
// Only one path if passwordless, other variants shouldn't see an empty user.
if passwordless {
return a.authenticatePasswordless(ctx, req)
}
// Try 2nd-factor-enabled authentication schemes first.
var authenticateFn func() (*types.MFADevice, error)
var authErr error // error message kept obscure on purpose, use logging for details
switch {
// cases in order of preference
case req.HeadlessAuthenticationID != "":
// handle authentication before the user lock to prevent locking out users
// due to timed-out/canceled headless authentication attempts.
mfaDevice, err := a.authenticateHeadless(ctx, req)
if err != nil {
log.Debugf("Headless Authentication for user %q failed while waiting for approval: %v", user, err)
return nil, "", trace.Wrap(authenticateHeadlessError)
}
authenticateFn = func() (*types.MFADevice, error) {
return mfaDevice, nil
}
authErr = authenticateHeadlessError
case req.Webauthn != nil:
authenticateFn = func() (*types.MFADevice, error) {
if req.Pass != nil {
if err = a.checkPasswordWOToken(user, req.Pass.Password); err != nil {
return nil, trace.Wrap(err)
}
}
mfaResponse := &proto.MFAAuthenticateResponse{
Response: &proto.MFAAuthenticateResponse_Webauthn{
Webauthn: wantypes.CredentialAssertionResponseToProto(req.Webauthn),
},
}
requiredExt := &mfav1.ChallengeExtensions{Scope: mfav1.ChallengeScope_CHALLENGE_SCOPE_LOGIN}
mfaData, err := a.ValidateMFAAuthResponse(ctx, mfaResponse, user, requiredExt)
if err != nil {
return nil, trace.Wrap(err)
}
return mfaData.Device, nil
}
authErr = authenticateWebauthnError
case req.OTP != nil:
authenticateFn = func() (*types.MFADevice, error) {
// OTP cannot be validated by validateMFAAuthResponse because we need to
// check the user's password too.
res, err := a.checkPassword(user, req.OTP.Password, req.OTP.Token)
if err != nil {
return nil, trace.Wrap(err)
}
return res.mfaDev, nil
}
authErr = invalidUserPass2FError
}
if authenticateFn != nil {
err := a.WithUserLock(ctx, user, func() error {
var err error
mfaDev, err = authenticateFn()
return err
})
switch {
case err != nil:
log.Debugf("User %v failed to authenticate: %v.", user, err)
if fieldErr := getErrorByTraceField(err); fieldErr != nil {
return nil, "", trace.Wrap(fieldErr)
}
return nil, "", trace.Wrap(authErr)
case mfaDev == nil:
log.Debugf(
"MFA authentication returned nil device (Webauthn = %v, TOTP = %v, Headless = %v): %v.",
req.Webauthn != nil, req.OTP != nil, req.HeadlessAuthenticationID != "", err)
return nil, "", trace.Wrap(authErr)
default:
return mfaDev, user, nil
}
}
// Try password-only authentication last.
if req.Pass == nil {
return nil, "", trace.AccessDenied("unsupported authentication method")
}
authPreference, err := a.GetAuthPreference(ctx)
if err != nil {
return nil, "", trace.Wrap(err)
}
// When using password only make sure that auth preference does not require
// second factor, otherwise users could bypass it.
switch authPreference.GetSecondFactor() {
case constants.SecondFactorOff:
// No 2FA required, check password only.
case constants.SecondFactorOptional:
// 2FA is optional. Make sure that a user does not have MFA devices
// registered.
devs, err := a.Services.GetMFADevices(ctx, user, false /* withSecrets */)
if err != nil && !trace.IsNotFound(err) {
return nil, "", trace.Wrap(err)
}
if len(devs) != 0 {
log.Warningf("MFA bypass attempt by user %q, access denied.", user)
return nil, "", trace.AccessDenied("missing second factor authentication")
}
default:
// Some form of MFA is required but none provided. Either client is
// buggy (didn't send MFA response) or someone is trying to bypass
// MFA.
log.Warningf("MFA bypass attempt by user %q, access denied.", user)
return nil, "", trace.AccessDenied("missing second factor")
}
if err = a.WithUserLock(ctx, user, func() error {
return a.checkPasswordWOToken(user, req.Pass.Password)
}); err != nil {
if fieldErr := getErrorByTraceField(err); fieldErr != nil {
return nil, "", trace.Wrap(fieldErr)
}
// provide obscure message on purpose, while logging the real
// error server side
log.Debugf("User %v failed to authenticate: %v.", user, err)
return nil, "", trace.Wrap(invalidUserPassError)
}
return nil, user, nil
}
func (a *Server) authenticatePasswordless(ctx context.Context, req AuthenticateUserRequest) (*types.MFADevice, string, error) {
mfaResponse := &proto.MFAAuthenticateResponse{
Response: &proto.MFAAuthenticateResponse_Webauthn{
Webauthn: wantypes.CredentialAssertionResponseToProto(req.Webauthn),
},
}
requiredExt := &mfav1.ChallengeExtensions{Scope: mfav1.ChallengeScope_CHALLENGE_SCOPE_PASSWORDLESS_LOGIN}
mfaData, err := a.ValidateMFAAuthResponse(ctx, mfaResponse, "" /* user */, requiredExt)
if err != nil {
log.Debugf("Passwordless authentication failed: %v", err)
return nil, "", trace.Wrap(authenticateWebauthnError)
}
// A distinction between passwordless and "plain" MFA is that we can't
// acquire the user lock beforehand (or at all on failures!)
// We do grab it here so successful logins go through the regular process.
if err := a.WithUserLock(ctx, mfaData.User, func() error { return nil }); err != nil {
log.Debugf("WithUserLock for user %q failed during passwordless authentication: %v", mfaData.User, err)
return nil, mfaData.User, trace.Wrap(authenticateWebauthnError)
}
return mfaData.Device, mfaData.User, nil
}
func (a *Server) authenticateHeadless(ctx context.Context, req AuthenticateUserRequest) (mfa *types.MFADevice, err error) {
// Delete the headless authentication upon failure.
defer func() {
if err != nil {
if err := a.DeleteHeadlessAuthentication(a.CloseContext(), req.Username, req.HeadlessAuthenticationID); err != nil && !trace.IsNotFound(err) {
log.Debugf("Failed to delete headless authentication: %v", err)
}
}
}()
// this authentication requires two client callbacks to create a headless authentication
// stub and approve/deny the headless authentication.
ctx, cancel := context.WithTimeout(ctx, defaults.HeadlessLoginTimeout)
defer cancel()
// Headless Authentication should expire when the callback expires.
expires := a.clock.Now().Add(defaults.HeadlessLoginTimeout)
// Create the headless authentication and validate request details.
ha, err := types.NewHeadlessAuthentication(req.Username, req.HeadlessAuthenticationID, expires)
if err != nil {
return nil, trace.Wrap(err)
}
ha.State = types.HeadlessAuthenticationState_HEADLESS_AUTHENTICATION_STATE_PENDING
ha.PublicKey = req.PublicKey
ha.ClientIpAddress = req.ClientMetadata.RemoteAddr
if err := services.ValidateHeadlessAuthentication(ha); err != nil {
return nil, trace.Wrap(err)
}
emitHeadlessLoginEvent(ctx, events.UserHeadlessLoginRequestedCode, a.emitter, ha, nil)
// HTTP server has shorter WriteTimeout than is needed, so we override WriteDeadline of the connection.
if conn, err := authz.ConnFromContext(ctx); err == nil {
if err := conn.SetWriteDeadline(a.GetClock().Now().Add(defaults.HeadlessLoginTimeout)); err != nil {
return nil, trace.Wrap(err)
}
}
// Headless authentication requests are made without any prior authentication. To avoid DDos
// attacks on the Auth server's backend, we don't create the headless authentication in the
// backend until an authenticated client creates a headless authentication stub. This serves
// as indirect authorization to insert the full headless authentication details into the backend.
if _, err := a.waitForHeadlessStub(ctx, ha); err != nil {
return nil, trace.Wrap(err)
}
if err := a.UpsertHeadlessAuthentication(ctx, ha); err != nil {
return nil, trace.Wrap(err)
}
// Wait for the request to be approved/denied.
approvedHeadlessAuthn, err := a.waitForHeadlessApproval(ctx, req.Username, req.HeadlessAuthenticationID)
if err != nil {
return nil, trace.Wrap(err)
}
// Verify that the headless authentication has not been tampered with.
if approvedHeadlessAuthn.User != req.Username {
return nil, trace.AccessDenied("headless authentication user mismatch")
}
if !bytes.Equal(req.PublicKey, ha.PublicKey) {
return nil, trace.AccessDenied("headless authentication public key mismatch")
}
return approvedHeadlessAuthn.MfaDevice, nil
}
func (a *Server) waitForHeadlessStub(ctx context.Context, ha *types.HeadlessAuthentication) (*types.HeadlessAuthentication, error) {
sub, err := a.headlessAuthenticationWatcher.Subscribe(ctx, ha.User, services.HeadlessAuthenticationUserStubID)
if err != nil {
return nil, trace.Wrap(err)
}
defer sub.Close()
stub, err := sub.WaitForUpdate(ctx, func(ha *types.HeadlessAuthentication) (bool, error) {
return true, nil
})
if err != nil {
return nil, trace.Wrap(err)
}
return stub, nil
}
func (a *Server) waitForHeadlessApproval(ctx context.Context, username, reqID string) (*types.HeadlessAuthentication, error) {
sub, err := a.headlessAuthenticationWatcher.Subscribe(ctx, username, reqID)
if err != nil {
return nil, trace.Wrap(err)
}
defer sub.Close()
headlessAuthn, err := sub.WaitForUpdate(ctx, func(ha *types.HeadlessAuthentication) (bool, error) {
switch ha.State {
case types.HeadlessAuthenticationState_HEADLESS_AUTHENTICATION_STATE_APPROVED:
if ha.MfaDevice == nil {
return false, trace.AccessDenied("expected mfa approval for headless authentication approval")
}
return true, nil
case types.HeadlessAuthenticationState_HEADLESS_AUTHENTICATION_STATE_DENIED:
return false, trace.AccessDenied("headless authentication denied")
}
return false, nil
})
if err != nil {
return nil, trace.Wrap(err)
}
return headlessAuthn, nil
}
// AuthenticateWebUser authenticates web user, creates and returns a web session
// if authentication is successful. In case the existing session ID is used to authenticate,
// returns the existing session instead of creating a new one
func (a *Server) AuthenticateWebUser(ctx context.Context, req AuthenticateUserRequest) (types.WebSession, error) {
username := req.Username // Empty if passwordless.
authPref, err := a.GetAuthPreference(ctx)
if err != nil {
return nil, trace.Wrap(err)
}
// Disable all local auth requests,
// except session ID renewal requests that are using the same method.
// This condition uses Session as a blanket check, because any new method added
// to the local auth will be disabled by default.
if !authPref.GetAllowLocalAuth() && req.Session == nil {
a.emitNoLocalAuthEvent(username)
return nil, trace.AccessDenied(noLocalAuth)
}
if req.Session != nil {
session, err := a.GetWebSession(ctx, types.GetWebSessionRequest{
User: username,
SessionID: req.Session.ID,
})
if err != nil {
return nil, trace.AccessDenied("session is invalid or has expired")
}
return session, nil
}
user, _, err := a.AuthenticateUser(ctx, req)
if err != nil {
return nil, trace.Wrap(err)
}
loginIP := ""
if req.ClientMetadata != nil {
loginIP, _, err = net.SplitHostPort(req.ClientMetadata.RemoteAddr)
if err != nil {
return nil, trace.Wrap(err)
}
}
sess, err := a.CreateWebSessionFromReq(ctx, types.NewWebSessionRequest{
User: user.GetName(),
LoginIP: loginIP,
Roles: user.GetRoles(),
Traits: user.GetTraits(),
LoginTime: a.clock.Now().UTC(),
AttestWebSession: true,
})
if err != nil {
return nil, trace.Wrap(err)
}
return sess, nil
}
// AuthenticateSSHRequest is a request to authenticate SSH client user via CLI
type AuthenticateSSHRequest struct {
// AuthenticateUserRequest is a request with credentials
AuthenticateUserRequest
// TTL is a requested TTL for certificates to be issues
TTL time.Duration `json:"ttl"`
// CompatibilityMode sets certificate compatibility mode with old SSH clients
CompatibilityMode string `json:"compatibility_mode"`
RouteToCluster string `json:"route_to_cluster"`
// KubernetesCluster sets the target kubernetes cluster for the TLS
// certificate. This can be empty on older clients.
KubernetesCluster string `json:"kubernetes_cluster"`
// AttestationStatement is an attestation statement associated with the given public key.
AttestationStatement *keys.AttestationStatement `json:"attestation_statement,omitempty"`
}
// CheckAndSetDefaults checks and sets default certificate values
func (a *AuthenticateSSHRequest) CheckAndSetDefaults() error {
if err := a.AuthenticateUserRequest.CheckAndSetDefaults(); err != nil {
return trace.Wrap(err)
}
if len(a.PublicKey) == 0 {
return trace.BadParameter("missing parameter 'public_key'")
}
certificateFormat, err := utils.CheckCertificateFormatFlag(a.CompatibilityMode)
if err != nil {
return trace.Wrap(err)
}
a.CompatibilityMode = certificateFormat
return nil
}
// SSHLoginResponse is a response returned by web proxy, it preserves backwards compatibility
// on the wire, which is the primary reason for non-matching json tags
type SSHLoginResponse struct {
// User contains a logged-in user information
Username string `json:"username"`
// Cert is a PEM encoded signed certificate
Cert []byte `json:"cert"`
// TLSCertPEM is a PEM encoded TLS certificate signed by TLS certificate authority
TLSCert []byte `json:"tls_cert"`
// HostSigners is a list of signing host public keys trusted by proxy
HostSigners []TrustedCerts `json:"host_signers"`
}
// TrustedCerts contains host certificates, it preserves backwards compatibility
// on the wire, which is the primary reason for non-matching json tags
type TrustedCerts struct {
// ClusterName identifies teleport cluster name this authority serves,
// for host authorities that means base hostname of all servers,
// for user authorities that means organization name
ClusterName string `json:"domain_name"`
// AuthorizedKeys is a list of SSH public keys in authorized_keys format
// that can be used to check host key signatures.
AuthorizedKeys [][]byte `json:"checking_keys"`
// TLSCertificates is a list of TLS certificates of the certificate authority
// of the authentication server
TLSCertificates [][]byte `json:"tls_certs"`
}
// SSHCertPublicKeys returns a list of trusted host SSH certificate authority public keys
func (c *TrustedCerts) SSHCertPublicKeys() ([]ssh.PublicKey, error) {
out := make([]ssh.PublicKey, 0, len(c.AuthorizedKeys))
for _, keyBytes := range c.AuthorizedKeys {
publicKey, _, _, _, err := ssh.ParseAuthorizedKey(keyBytes)
if err != nil {
return nil, trace.Wrap(err)
}
out = append(out, publicKey)
}
return out, nil
}
// AuthoritiesToTrustedCerts serializes authorities to TrustedCerts data structure
func AuthoritiesToTrustedCerts(authorities []types.CertAuthority) []TrustedCerts {
out := make([]TrustedCerts, len(authorities))
for i, ca := range authorities {
out[i] = TrustedCerts{
ClusterName: ca.GetClusterName(),
AuthorizedKeys: services.GetSSHCheckingKeys(ca),
TLSCertificates: services.GetTLSCerts(ca),
}
}
return out
}
// AuthenticateSSHUser authenticates an SSH user and returns SSH and TLS
// certificates for the public key in req.
func (a *Server) AuthenticateSSHUser(ctx context.Context, req AuthenticateSSHRequest) (*SSHLoginResponse, error) {
username := req.Username // Empty if passwordless.
authPref, err := a.GetAuthPreference(ctx)
if err != nil {
return nil, trace.Wrap(err)
}
if !authPref.GetAllowLocalAuth() {
a.emitNoLocalAuthEvent(username)
return nil, trace.AccessDenied(noLocalAuth)
}
clusterName, err := a.GetClusterName()
if err != nil {
return nil, trace.Wrap(err)
}
// It's safe to extract the roles and traits directly from services.User as
// this endpoint is only used for local accounts.
user, checker, err := a.AuthenticateUser(ctx, req.AuthenticateUserRequest)
if err != nil {
return nil, trace.Wrap(err)
}
// Return the host CA for this cluster only.
authority, err := a.GetCertAuthority(ctx, types.CertAuthID{
Type: types.HostCA,
DomainName: clusterName.GetClusterName(),
}, false)
if err != nil {
return nil, trace.Wrap(err)
}
hostCertAuthorities := []types.CertAuthority{
authority,
}
clientIP := ""
if req.ClientMetadata != nil && req.ClientMetadata.RemoteAddr != "" {
host, err := utils.Host(req.ClientMetadata.RemoteAddr)
if err != nil {
return nil, trace.Wrap(err)
}
clientIP = host
}
if checker.PinSourceIP() && clientIP == "" {
return nil, trace.BadParameter("source IP pinning is enabled but client IP is unknown")
}
certReq := certRequest{
user: user,
ttl: req.TTL,
publicKey: req.PublicKey,
compatibility: req.CompatibilityMode,
checker: checker,
traits: user.GetTraits(),
routeToCluster: req.RouteToCluster,
kubernetesCluster: req.KubernetesCluster,
loginIP: clientIP,
attestationStatement: req.AttestationStatement,
}
// For headless authentication, a short-lived mfa-verified cert should be generated.
if req.HeadlessAuthenticationID != "" {
ha, err := a.GetHeadlessAuthentication(ctx, req.Username, req.HeadlessAuthenticationID)
if err != nil {
return nil, trace.Wrap(err)
}
if !bytes.Equal(req.PublicKey, ha.PublicKey) {
return nil, trace.AccessDenied("headless authentication public key mismatch")
}
certReq.mfaVerified = ha.MfaDevice.Metadata.Name
certReq.ttl = time.Minute
}
certs, err := a.generateUserCert(ctx, certReq)
if err != nil {
return nil, trace.Wrap(err)
}
UserLoginCount.Inc()
return &SSHLoginResponse{
Username: user.GetName(),
Cert: certs.SSH,
TLSCert: certs.TLS,
HostSigners: AuthoritiesToTrustedCerts(hostCertAuthorities),
}, nil
}
// emitNoLocalAuthEvent creates and emits a local authentication is disabled message.
func (a *Server) emitNoLocalAuthEvent(username string) {
if err := a.emitter.EmitAuditEvent(a.closeCtx, &apievents.AuthAttempt{
Metadata: apievents.Metadata{
Type: events.AuthAttemptEvent,
Code: events.AuthAttemptFailureCode,
},
UserMetadata: apievents.UserMetadata{
User: username,
},
Status: apievents.Status{
Success: false,
Error: noLocalAuth,
},
}); err != nil {
log.WithError(err).Warn("Failed to emit no local auth event.")
}
}
func (a *Server) createUserWebSession(ctx context.Context, user services.UserState, loginIP string) (types.WebSession, error) {
// It's safe to extract the roles and traits directly from services.User as this method
// is only used for local accounts.
return a.CreateWebSessionFromReq(ctx, types.NewWebSessionRequest{
User: user.GetName(),
LoginIP: loginIP,
Roles: user.GetRoles(),
Traits: user.GetTraits(),
LoginTime: a.clock.Now().UTC(),
})
}
func getErrorByTraceField(err error) error {
traceErr, ok := err.(trace.Error)
switch {
case !ok:
log.WithError(err).Warn("Unexpected error type, wanted TraceError")
return trace.AccessDenied("an error has occurred")
case traceErr.GetFields()[ErrFieldKeyUserMaxedAttempts] != nil:
return trace.AccessDenied(MaxFailedAttemptsErrMsg)
}
return nil
}
func trimUserAgent(userAgent string) string {
if len(userAgent) > maxUserAgentLen {
return userAgent[:maxUserAgentLen-3] + "..."
}
return userAgent
}
const noLocalAuth = "local auth disabled"