Implement the “authproxy” connector (for Apache2 mod_auth etc.)

This commit is contained in:
Michael Stapelberg 2017-10-21 16:54:54 +02:00
parent f3c85e6936
commit a41d93db4a
12 changed files with 168 additions and 12 deletions

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@ -0,0 +1,87 @@
# External authentication
## Overview
The authproxy connector returns identities based on authentication which your
front-end web server performs.
The connector does not support refresh tokens or groups at this point.
## Configuration
The following is an example config file that can be used by the external
connector to authenticate a user.
```yaml
connectors:
- type: authproxy
id: myBasicAuth
name: HTTP Basic Auth
```
The authproxy connector assumes that you configured your front-end web server
such that it performs authentication for the `/dex/callback/myBasicAuth`
location and provides the result in the X-Remote-User HTTP header. The following
configuration will work for Apache 2.4.10+:
```
<Location /dex/callback/myBasicAuth>
AuthType Basic
AuthName "db.debian.org webPassword"
AuthBasicProvider file
AuthUserFile "/etc/apache2/debian-web-pw.htpasswd"
Require valid-user
# Defense in depth: clear the Authorization header so that
# Debian Web Passwords never even reach dex.
RequestHeader unset Authorization
# Requires Apache 2.4.10+
RequestHeader set X-Remote-User expr=%{REMOTE_USER}@debian.org
ProxyPass "http://localhost:5556/dex/callback/myBasicAuth"
ProxyPassReverse "http://localhost:5556/dex/callback/myBasicAuth"
</Location>
```
## Full Apache2 setup
After installing your Linux distributions Apache2 package, place the following
virtual host configuration in e.g. `/etc/apache2/sites-available/sso.conf`:
```
<VirtualHost sso.example.net>
ServerName sso.example.net
ServerAdmin webmaster@localhost
DocumentRoot /var/www/html
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
<Location /dex/>
ProxyPass "http://localhost:5556/dex/"
ProxyPassReverse "http://localhost:5556/dex/"
</Location>
<Location /dex/callback/myBasicAuth>
AuthType Basic
AuthName "db.debian.org webPassword"
AuthBasicProvider file
AuthUserFile "/etc/apache2/debian-web-pw.htpasswd"
Require valid-user
# Defense in depth: clear the Authorization header so that
# Debian Web Passwords never even reach dex.
RequestHeader unset Authorization
# Requires Apache 2.4.10+
RequestHeader set X-Remote-User expr=%{REMOTE_USER}@debian.org
ProxyPass "http://localhost:5556/dex/callback/myBasicAuth"
ProxyPassReverse "http://localhost:5556/dex/callback/myBasicAuth"
</Location>
</VirtualHost>
```
Then, enable it using `a2ensite sso.conf`, followed by a restart of Apache2.

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@ -67,6 +67,7 @@ More docs for running dex as a Kubernetes authenticator can be found [here](Docu
* [GitLab](Documentation/gitlab-connector.md)
* [SAML 2.0](Documentation/saml-connector.md)
* [OpenID Connect](Documentation/oidc-connector.md) (includes Google, Salesforce, Azure, etc.)
* [authproxy](Documentation/authproxy.md) (Apache2 mod_auth, etc.)
* Client libraries
* [Go][go-oidc]

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@ -0,0 +1,56 @@
// Package authproxy implements a connector which relies on external
// authentication (e.g. mod_auth in Apache2) and returns an identity with the
// HTTP header X-Remote-User as verified email.
package authproxy
import (
"fmt"
"net/http"
"net/url"
"github.com/coreos/dex/connector"
"github.com/sirupsen/logrus"
)
// Config holds the configuration parameters for a connector which returns an
// identity with the HTTP header X-Remote-User as verified email.
type Config struct{}
// Open returns an authentication strategy which requires no user interaction.
func (c *Config) Open(id string, logger logrus.FieldLogger) (connector.Connector, error) {
return &callback{logger: logger, pathSuffix: "/" + id}, nil
}
// Callback is a connector which returns an identity with the HTTP header
// X-Remote-User as verified email.
type callback struct {
logger logrus.FieldLogger
pathSuffix string
}
// LoginURL returns the URL to redirect the user to login with.
func (m *callback) LoginURL(s connector.Scopes, callbackURL, state string) (string, error) {
u, err := url.Parse(callbackURL)
if err != nil {
return "", fmt.Errorf("failed to parse callbackURL %q: %v", callbackURL, err)
}
u.Path = u.Path + m.pathSuffix
v := u.Query()
v.Set("state", state)
u.RawQuery = v.Encode()
return u.String(), nil
}
// HandleCallback parses the request and returns the user's identity
func (m *callback) HandleCallback(s connector.Scopes, r *http.Request) (connector.Identity, error) {
remoteUser := r.Header.Get("X-Remote-User")
if remoteUser == "" {
return connector.Identity{}, fmt.Errorf("required HTTP header X-Remote-User is not set")
}
// TODO: add support for X-Remote-Group, see
// https://kubernetes.io/docs/admin/authentication/#authenticating-proxy
return connector.Identity{
Email: remoteUser,
EmailVerified: true,
}, nil
}

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@ -63,7 +63,7 @@ type Org struct {
}
// Open returns a strategy for logging in through GitHub.
func (c *Config) Open(logger logrus.FieldLogger) (connector.Connector, error) {
func (c *Config) Open(id string, logger logrus.FieldLogger) (connector.Connector, error) {
if c.Org != "" {
// Return error if both 'org' and 'orgs' fields are used.

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@ -51,7 +51,7 @@ type gitlabGroup struct {
}
// Open returns a strategy for logging in through GitLab.
func (c *Config) Open(logger logrus.FieldLogger) (connector.Connector, error) {
func (c *Config) Open(id string, logger logrus.FieldLogger) (connector.Connector, error) {
if c.BaseURL == "" {
c.BaseURL = "https://www.gitlab.com"
}

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@ -153,7 +153,7 @@ func parseScope(s string) (int, bool) {
}
// Open returns an authentication strategy using LDAP.
func (c *Config) Open(logger logrus.FieldLogger) (connector.Connector, error) {
func (c *Config) Open(id string, logger logrus.FieldLogger) (connector.Connector, error) {
conn, err := c.OpenConnector(logger)
if err != nil {
return nil, err

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@ -69,7 +69,7 @@ func (m *Callback) Refresh(ctx context.Context, s connector.Scopes, identity con
type CallbackConfig struct{}
// Open returns an authentication strategy which requires no user interaction.
func (c *CallbackConfig) Open(logger logrus.FieldLogger) (connector.Connector, error) {
func (c *CallbackConfig) Open(id string, logger logrus.FieldLogger) (connector.Connector, error) {
return NewCallbackConnector(logger), nil
}
@ -81,7 +81,7 @@ type PasswordConfig struct {
}
// Open returns an authentication strategy which prompts for a predefined username and password.
func (c *PasswordConfig) Open(logger logrus.FieldLogger) (connector.Connector, error) {
func (c *PasswordConfig) Open(id string, logger logrus.FieldLogger) (connector.Connector, error) {
if c.Username == "" {
return nil, errors.New("no username supplied")
}

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@ -75,7 +75,7 @@ func registerBrokenAuthHeaderProvider(url string) {
// Open returns a connector which can be used to login users through an upstream
// OpenID Connect provider.
func (c *Config) Open(logger logrus.FieldLogger) (conn connector.Connector, err error) {
func (c *Config) Open(id string, logger logrus.FieldLogger) (conn connector.Connector, err error) {
ctx, cancel := context.WithCancel(context.Background())
provider, err := oidc.NewProvider(ctx, c.Issuer)

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@ -1,12 +1,13 @@
package oidc
import (
"github.com/coreos/dex/connector"
"github.com/sirupsen/logrus"
"net/url"
"os"
"reflect"
"testing"
"github.com/coreos/dex/connector"
"github.com/sirupsen/logrus"
)
func TestKnownBrokenAuthHeaderProvider(t *testing.T) {
@ -73,7 +74,7 @@ func TestOidcConnector_LoginURL(t *testing.T) {
HostedDomains: test.hostedDomains,
}
conn, err := config.Open(logger)
conn, err := config.Open("oidc", logger)
if err != nil {
t.Errorf("failed to open connector: %v", err)
continue

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@ -125,7 +125,7 @@ func (c certStore) Certificates() (roots []*x509.Certificate, err error) {
// Open validates the config and returns a connector. It does not actually
// validate connectivity with the provider.
func (c *Config) Open(logger logrus.FieldLogger) (connector.Connector, error) {
func (c *Config) Open(id string, logger logrus.FieldLogger) (connector.Connector, error) {
return c.openConnector(logger)
}

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@ -346,6 +346,12 @@ func (s *Server) handleConnectorCallback(w http.ResponseWriter, r *http.Request)
return
}
if connID := mux.Vars(r)["connector"]; connID != "" && connID != authReq.ConnectorID {
s.logger.Errorf("Connector mismatch: authentication started with id %q, but callback for id %q was triggered", authReq.ConnectorID, connID)
s.renderError(w, http.StatusInternalServerError, "Requested resource does not exist.")
return
}
conn, err := s.getConnector(authReq.ConnectorID)
if err != nil {
s.logger.Errorf("Failed to get connector with id %q : %v", authReq.ConnectorID, err)

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@ -19,6 +19,7 @@ import (
"github.com/sirupsen/logrus"
"github.com/coreos/dex/connector"
"github.com/coreos/dex/connector/authproxy"
"github.com/coreos/dex/connector/github"
"github.com/coreos/dex/connector/gitlab"
"github.com/coreos/dex/connector/ldap"
@ -240,6 +241,9 @@ func newServer(ctx context.Context, c Config, rotationStrategy rotationStrategy)
handleFunc("/auth", s.handleAuthorization)
handleFunc("/auth/{connector}", s.handleConnectorLogin)
handleFunc("/callback", s.handleConnectorCallback)
// For easier connector-specific web server configuration, e.g. for the
// "authproxy" connector.
handleFunc("/callback/{connector}", s.handleConnectorCallback)
handleFunc("/approval", s.handleApproval)
handleFunc("/healthz", s.handleHealth)
handlePrefix("/static", static)
@ -381,7 +385,7 @@ func (s *Server) startGarbageCollection(ctx context.Context, frequency time.Dura
// ConnectorConfig is a configuration that can open a connector.
type ConnectorConfig interface {
Open(logrus.FieldLogger) (connector.Connector, error)
Open(id string, logger logrus.FieldLogger) (connector.Connector, error)
}
// ConnectorsConfig variable provides an easy way to return a config struct
@ -394,6 +398,7 @@ var ConnectorsConfig = map[string]func() ConnectorConfig{
"gitlab": func() ConnectorConfig { return new(gitlab.Config) },
"oidc": func() ConnectorConfig { return new(oidc.Config) },
"saml": func() ConnectorConfig { return new(saml.Config) },
"authproxy": func() ConnectorConfig { return new(authproxy.Config) },
// Keep around for backwards compatibility.
"samlExperimental": func() ConnectorConfig { return new(saml.Config) },
}
@ -415,7 +420,7 @@ func openConnector(logger logrus.FieldLogger, conn storage.Connector) (connector
}
}
c, err := connConfig.Open(logger)
c, err := connConfig.Open(conn.ID, logger)
if err != nil {
return c, fmt.Errorf("failed to create connector %s: %v", conn.ID, err)
}