pomerium/proxy/proxy.go
2019-11-09 19:53:11 -05:00

304 lines
10 KiB
Go
Executable file

package proxy // import "github.com/pomerium/pomerium/proxy"
import (
"crypto/cipher"
"crypto/tls"
"encoding/base64"
"fmt"
"html/template"
"net/http"
"net/url"
"time"
"github.com/gorilla/mux"
"github.com/pomerium/pomerium/config"
"github.com/pomerium/pomerium/internal/cryptutil"
"github.com/pomerium/pomerium/internal/encoding"
"github.com/pomerium/pomerium/internal/encoding/jws"
"github.com/pomerium/pomerium/internal/httputil"
"github.com/pomerium/pomerium/internal/log"
"github.com/pomerium/pomerium/internal/middleware"
"github.com/pomerium/pomerium/internal/sessions"
"github.com/pomerium/pomerium/internal/telemetry/metrics"
"github.com/pomerium/pomerium/internal/templates"
"github.com/pomerium/pomerium/internal/tripper"
"github.com/pomerium/pomerium/internal/urlutil"
"github.com/pomerium/pomerium/proxy/clients"
)
const (
// dashboardURL is the path to authenticate's sign in endpoint
dashboardURL = "/.pomerium"
// signinURL is the path to authenticate's sign in endpoint
signinURL = "/.pomerium/sign_in"
// signoutURL is the path to authenticate's sign out endpoint
signoutURL = "/.pomerium/sign_out"
)
// ValidateOptions checks that proper configuration settings are set to create
// a proper Proxy instance
func ValidateOptions(o config.Options) error {
if _, err := cryptutil.NewAEADCipherFromBase64(o.SharedKey); err != nil {
return fmt.Errorf("proxy: invalid 'SHARED_SECRET': %v", err)
}
if _, err := cryptutil.NewAEADCipherFromBase64(o.CookieSecret); err != nil {
return fmt.Errorf("proxy: invalid 'COOKIE_SECRET': %v", err)
}
if err := urlutil.ValidateURL(o.AuthenticateURL); err != nil {
return fmt.Errorf("proxy: invalid 'AUTHENTICATE_SERVICE_URL': %v", err)
}
if err := urlutil.ValidateURL(o.AuthorizeURL); err != nil {
return fmt.Errorf("proxy: invalid 'AUTHORIZE_SERVICE_URL': %v", err)
}
if len(o.SigningKey) != 0 {
if _, err := jws.NewES256Signer(o.SigningKey, ""); err != nil {
return fmt.Errorf("proxy: invalid 'SIGNING_KEY': %v", err)
}
}
return nil
}
// Proxy stores all the information associated with proxying a request.
type Proxy struct {
// SharedKey used to mutually authenticate service communication
SharedKey string
sharedCipher cipher.AEAD
authenticateURL *url.URL
authenticateSigninURL *url.URL
authenticateSignoutURL *url.URL
authorizeURL *url.URL
AuthorizeClient clients.Authorizer
encoder encoding.Unmarshaler
cookieOptions *sessions.CookieOptions
cookieSecret []byte
defaultUpstreamTimeout time.Duration
refreshCooldown time.Duration
Handler http.Handler
sessionStore sessions.SessionStore
sessionLoaders []sessions.SessionLoader
signingKey string
templates *template.Template
}
// New takes a Proxy service from options and a validation function.
// Function returns an error if options fail to validate.
func New(opts config.Options) (*Proxy, error) {
if err := ValidateOptions(opts); err != nil {
return nil, err
}
sharedCipher, _ := cryptutil.NewAEADCipherFromBase64(opts.SharedKey)
decodedCookieSecret, _ := base64.StdEncoding.DecodeString(opts.CookieSecret)
// used to load and verify JWT tokens signed by the authenticate service
encoder, err := jws.NewHS256Signer([]byte(opts.SharedKey), opts.AuthenticateURL.Host)
if err != nil {
return nil, err
}
cookieOptions := &sessions.CookieOptions{
Name: opts.CookieName,
Domain: opts.CookieDomain,
Secure: opts.CookieSecure,
HTTPOnly: opts.CookieHTTPOnly,
Expire: opts.CookieExpire,
}
cookieStore, err := sessions.NewCookieLoader(cookieOptions, encoder)
if err != nil {
return nil, err
}
p := &Proxy{
SharedKey: opts.SharedKey,
sharedCipher: sharedCipher,
encoder: encoder,
cookieSecret: decodedCookieSecret,
cookieOptions: cookieOptions,
defaultUpstreamTimeout: opts.DefaultUpstreamTimeout,
refreshCooldown: opts.RefreshCooldown,
sessionStore: cookieStore,
sessionLoaders: []sessions.SessionLoader{
cookieStore,
sessions.NewHeaderStore(encoder, "Pomerium"),
sessions.NewQueryParamStore(encoder, "pomerium_session")},
signingKey: opts.SigningKey,
templates: templates.New(),
}
// errors checked in ValidateOptions
p.authorizeURL, _ = urlutil.DeepCopy(opts.AuthorizeURL)
p.authenticateURL, _ = urlutil.DeepCopy(opts.AuthenticateURL)
p.authenticateSigninURL = p.authenticateURL.ResolveReference(&url.URL{Path: signinURL})
p.authenticateSignoutURL = p.authenticateURL.ResolveReference(&url.URL{Path: signoutURL})
if err := p.UpdatePolicies(&opts); err != nil {
return nil, err
}
metrics.AddPolicyCountCallback("proxy", func() int64 {
return int64(len(opts.Policies))
})
p.AuthorizeClient, err = clients.NewAuthorizeClient("grpc",
&clients.Options{
Addr: p.authorizeURL,
OverrideCertificateName: opts.OverrideCertificateName,
SharedSecret: opts.SharedKey,
CA: opts.CA,
CAFile: opts.CAFile,
RequestTimeout: opts.GRPCClientTimeout,
ClientDNSRoundRobin: opts.GRPCClientDNSRoundRobin,
WithInsecure: opts.GRPCInsecure,
})
return p, err
}
// UpdateOptions updates internal structures based on config.Options
func (p *Proxy) UpdateOptions(o config.Options) error {
if p == nil {
return nil
}
log.Info().Msg("proxy: updating options")
return p.UpdatePolicies(&o)
}
// UpdatePolicies updates the H basedon the configured policies
func (p *Proxy) UpdatePolicies(opts *config.Options) error {
var err error
if len(opts.Policies) == 0 {
log.Warn().Msg("proxy: configuration has no policies")
}
r := httputil.NewRouter()
r.NotFoundHandler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
httputil.ErrorResponse(w, r, httputil.Error(fmt.Sprintf("%s route unknown", r.Host), http.StatusNotFound, nil))
})
r.SkipClean(true)
r.StrictSlash(true)
r.HandleFunc("/robots.txt", p.RobotsTxt).Methods(http.MethodGet)
// dashboard handlers are registered to all routes
r = p.registerDashboardHandlers(r)
if opts.ForwardAuthURL != nil {
// if a forward auth endpoint is set, register its handlers
h := r.Host(opts.ForwardAuthURL.Host).Subrouter()
h.PathPrefix("/").Handler(p.registerFwdAuthHandlers())
}
for _, policy := range opts.Policies {
if err := policy.Validate(); err != nil {
return fmt.Errorf("proxy: invalid policy %s", err)
}
r, err = p.reverseProxyHandler(r, &policy)
if err != nil {
return err
}
}
p.Handler = r
return nil
}
func (p *Proxy) reverseProxyHandler(r *mux.Router, policy *config.Policy) (*mux.Router, error) {
// 1. Create the reverse proxy connection
proxy := httputil.NewReverseProxy(policy.Destination)
// 2. Override any custom transport settings (e.g. TLS settings, etc)
proxy.Transport = p.roundTripperFromPolicy(policy)
// 3. Create a sub-router for a given route's hostname (`httpbin.corp.example.com`)
rp := r.Host(policy.Source.Host).Subrouter()
rp.PathPrefix("/").Handler(proxy)
// Optional: If websockets are enabled, do not set a handler request timeout
// websockets cannot use the non-hijackable timeout-handler
if !policy.AllowWebsockets {
timeout := p.defaultUpstreamTimeout
if policy.UpstreamTimeout != 0 {
timeout = policy.UpstreamTimeout
}
timeoutMsg := fmt.Sprintf("%s timed out in %s", policy.Destination.Host, timeout)
rp.Use(middleware.TimeoutHandlerFunc(timeout, timeoutMsg))
}
// Optional: a cors preflight check, skip access control middleware
if policy.CORSAllowPreflight {
log.Warn().Str("route", policy.String()).Msg("proxy: cors preflight enabled")
rp.Use(middleware.CorsBypass(proxy))
}
// Optional: if a public route, skip access control middleware
if policy.AllowPublicUnauthenticatedAccess {
log.Warn().Str("route", policy.String()).Msg("proxy: all access control disabled")
return r, nil
}
// 4. Retrieve the user session and add it to the request context
rp.Use(sessions.RetrieveSession(p.sessionLoaders...))
// 5. Strip the user session cookie from the downstream request
rp.Use(middleware.StripCookie(p.cookieOptions.Name))
// 6. AuthN - Verify the user is authenticated. Set email, group, & id headers
rp.Use(p.AuthenticateSession)
// 7. AuthZ - Verify the user is authorized for route
rp.Use(p.AuthorizeSession)
// Optional: Add a signed JWT attesting to the user's id, email, and group
if len(p.signingKey) != 0 {
signer, err := jws.NewES256Signer(p.signingKey, policy.Destination.Host)
if err != nil {
return nil, err
}
rp.Use(p.SignRequest(signer))
}
// Optional: if additional headers are to be set for this url
if len(policy.SetRequestHeaders) != 0 {
log.Warn().Interface("headers", policy.SetRequestHeaders).Msg("proxy: set request headers")
rp.Use(SetResponseHeaders(policy.SetRequestHeaders))
}
return r, nil
}
// roundTripperFromPolicy adjusts the std library's `DefaultTransport RoundTripper`
// for a given route. A route's `RoundTripper` establishes network connections
// as needed and caches them for reuse by subsequent calls.
func (p *Proxy) roundTripperFromPolicy(policy *config.Policy) http.RoundTripper {
transport := http.DefaultTransport.(*http.Transport).Clone()
c := tripper.NewChain()
c = c.Append(metrics.HTTPMetricsRoundTripper("proxy", policy.Destination.Host))
var tlsClientConfig tls.Config
var isCustomClientConfig bool
if policy.TLSSkipVerify {
tlsClientConfig.InsecureSkipVerify = true
isCustomClientConfig = true
log.Warn().Str("policy", policy.String()).Msg("proxy: tls skip verify")
}
if policy.RootCAs != nil {
tlsClientConfig.RootCAs = policy.RootCAs
isCustomClientConfig = true
log.Debug().Str("policy", policy.String()).Msg("proxy: custom root ca")
}
if policy.ClientCertificate != nil {
tlsClientConfig.Certificates = []tls.Certificate{*policy.ClientCertificate}
isCustomClientConfig = true
log.Debug().Str("policy", policy.String()).Msg("proxy: client certs enabled")
}
if policy.TLSServerName != "" {
tlsClientConfig.ServerName = policy.TLSServerName
isCustomClientConfig = true
log.Debug().Str("policy", policy.String()).Msgf("proxy: tls override hostname: %s", policy.TLSServerName)
}
// We avoid setting a custom client config unless we have to as
// if TLSClientConfig is nil, the default configuration is used.
if isCustomClientConfig {
transport.TLSClientConfig = &tlsClientConfig
}
return c.Then(transport)
}