pomerium/proxy/proxy.go
2019-07-13 18:28:51 -07:00

311 lines
10 KiB
Go
Executable file

package proxy // import "github.com/pomerium/pomerium/proxy"
import (
"crypto/tls"
"crypto/x509"
"encoding/base64"
"errors"
"fmt"
"html/template"
stdlog "log"
"net/http"
"net/http/httputil"
"net/url"
"time"
"github.com/pomerium/pomerium/internal/config"
"github.com/pomerium/pomerium/internal/cryptutil"
"github.com/pomerium/pomerium/internal/log"
"github.com/pomerium/pomerium/internal/metrics"
"github.com/pomerium/pomerium/internal/middleware"
"github.com/pomerium/pomerium/internal/sessions"
"github.com/pomerium/pomerium/internal/templates"
"github.com/pomerium/pomerium/internal/tripper"
"github.com/pomerium/pomerium/proxy/clients"
)
const (
// HeaderJWT is the header key containing JWT signed user details.
HeaderJWT = "x-pomerium-jwt-assertion"
// HeaderUserID is the header key containing the user's id.
HeaderUserID = "x-pomerium-authenticated-user-id"
// HeaderEmail is the header key containing the user's email.
HeaderEmail = "x-pomerium-authenticated-user-email"
// HeaderGroups is the header key containing the user's groups.
HeaderGroups = "x-pomerium-authenticated-user-groups"
)
// ValidateOptions checks that proper configuration settings are set to create
// a proper Proxy instance
func ValidateOptions(o config.Options) error {
decoded, err := base64.StdEncoding.DecodeString(o.SharedKey)
if err != nil {
return fmt.Errorf("`SHARED_SECRET` setting is invalid base64: %v", err)
}
if len(decoded) != 32 {
return fmt.Errorf("`SHARED_SECRET` want 32 but got %d bytes", len(decoded))
}
if o.AuthenticateURL == nil || o.AuthenticateURL.String() == "" {
return errors.New("missing setting: authenticate-service-url")
}
if o.AuthenticateURL.Scheme != "https" {
return errors.New("authenticate-service-url must be a valid https url")
}
if o.AuthorizeURL == nil || o.AuthorizeURL.String() == "" {
return errors.New("missing setting: authorize-service-url")
}
if o.AuthorizeURL.Scheme != "https" {
return errors.New("authorize-service-url must be a valid https url")
}
if o.CookieSecret == "" {
return errors.New("missing setting: cookie-secret")
}
decodedCookieSecret, err := base64.StdEncoding.DecodeString(o.CookieSecret)
if err != nil {
return fmt.Errorf("cookie secret is invalid base64: %v", err)
}
if len(decodedCookieSecret) != 32 {
return fmt.Errorf("cookie secret expects 32 bytes but got %d", len(decodedCookieSecret))
}
if len(o.SigningKey) != 0 {
decodedSigningKey, err := base64.StdEncoding.DecodeString(o.SigningKey)
if err != nil {
return fmt.Errorf("signing key is invalid base64: %v", err)
}
_, err = cryptutil.NewES256Signer(decodedSigningKey, "localhost")
if err != nil {
return fmt.Errorf("invalid signing key is : %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
AuthenticateURL *url.URL
AuthenticateClient clients.Authenticator
AuthorizeClient clients.Authorizer
cipher cryptutil.Cipher
cookieName string
csrfStore sessions.CSRFStore
defaultUpstreamTimeout time.Duration
redirectURL *url.URL
refreshCooldown time.Duration
restStore sessions.SessionStore
routeConfigs map[string]*routeConfig
sessionStore sessions.SessionStore
signingKey string
templates *template.Template
}
type routeConfig struct {
mux http.Handler
policy config.Policy
}
// 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
}
// error explicitly handled by validate
decodedSecret, _ := base64.StdEncoding.DecodeString(opts.CookieSecret)
cipher, err := cryptutil.NewCipher(decodedSecret)
if err != nil {
return nil, fmt.Errorf("cookie-secret error: %s", err.Error())
}
cookieStore, err := sessions.NewCookieStore(
&sessions.CookieStoreOptions{
Name: opts.CookieName,
CookieDomain: opts.CookieDomain,
CookieSecure: opts.CookieSecure,
CookieHTTPOnly: opts.CookieHTTPOnly,
CookieExpire: opts.CookieExpire,
CookieCipher: cipher,
})
if err != nil {
return nil, err
}
restStore, err := sessions.NewRestStore(&sessions.RestStoreOptions{Cipher: cipher})
if err != nil {
return nil, err
}
p := &Proxy{
SharedKey: opts.SharedKey,
routeConfigs: make(map[string]*routeConfig),
// services
AuthenticateURL: opts.AuthenticateURL,
cipher: cipher,
cookieName: opts.CookieName,
csrfStore: cookieStore,
defaultUpstreamTimeout: opts.DefaultUpstreamTimeout,
redirectURL: &url.URL{Path: "/.pomerium/callback"},
refreshCooldown: opts.RefreshCooldown,
restStore: restStore,
sessionStore: cookieStore,
signingKey: opts.SigningKey,
templates: templates.New(),
}
if err := p.UpdatePolicies(&opts); err != nil {
return nil, err
}
p.AuthenticateClient, err = clients.NewAuthenticateClient("grpc",
&clients.Options{
Addr: opts.AuthenticateURL,
InternalAddr: opts.AuthenticateInternalAddr,
OverrideCertificateName: opts.OverrideCertificateName,
SharedSecret: opts.SharedKey,
CA: opts.CA,
CAFile: opts.CAFile,
})
if err != nil {
return nil, err
}
p.AuthorizeClient, err = clients.NewAuthorizeClient("grpc",
&clients.Options{
Addr: opts.AuthorizeURL,
OverrideCertificateName: opts.OverrideCertificateName,
SharedSecret: opts.SharedKey,
CA: opts.CA,
CAFile: opts.CAFile,
})
return p, err
}
// UpdatePolicies updates the handlers based on the configured policies
func (p *Proxy) UpdatePolicies(opts *config.Options) error {
routeConfigs := make(map[string]*routeConfig, len(opts.Policies))
if len(opts.Policies) == 0 {
log.Warn().Msg("proxy: configuration has no policies")
}
for _, policy := range opts.Policies {
if err := policy.Validate(); err != nil {
return fmt.Errorf("proxy: couldn't update policies %s", err)
}
proxy := NewReverseProxy(policy.Destination)
// build http transport (roundtripper) middleware chain
// todo(bdd): this will make vet complain, it is safe
// and can be replaced with transport.Clone() in go 1.13
// https://go-review.googlesource.com/c/go/+/174597/
// https://github.com/golang/go/issues/26013#issuecomment-399481302
transport := *(http.DefaultTransport.(*http.Transport))
c := tripper.NewChain()
c = c.Append(metrics.HTTPMetricsRoundTripper("proxy", policy.Destination.Host))
if policy.TLSSkipVerify {
transport.TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
}
if policy.TLSCustomCA != "" {
rootCA, err := p.customCAPool(policy.TLSCustomCA)
if err != nil {
return fmt.Errorf("proxy: couldn't add custom ca to policy %s", policy.From)
}
transport.TLSClientConfig = &tls.Config{RootCAs: rootCA}
}
proxy.Transport = c.Then(&transport)
handler, err := p.newReverseProxyHandler(proxy, &policy)
if err != nil {
return err
}
routeConfigs[policy.Source.Host] = &routeConfig{
mux: handler,
policy: policy,
}
}
p.routeConfigs = routeConfigs
return nil
}
// UpstreamProxy stores information for proxying the request to the upstream.
type UpstreamProxy struct {
name string
handler http.Handler
}
// ServeHTTP handles the second (reverse-proxying) leg of pomerium's request flow
func (u *UpstreamProxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
u.handler.ServeHTTP(w, r)
}
// NewReverseProxy returns a new ReverseProxy that routes URLs to the scheme, host, and
// base path provided in target. NewReverseProxy rewrites the Host header.
func NewReverseProxy(to *url.URL) *httputil.ReverseProxy {
proxy := httputil.NewSingleHostReverseProxy(to)
sublogger := log.With().Str("proxy", to.Host).Logger()
proxy.ErrorLog = stdlog.New(&log.StdLogWrapper{Logger: &sublogger}, "", 0)
director := proxy.Director
proxy.Director = func(req *http.Request) {
// Identifies the originating IP addresses of a client connecting to
// a web server through an HTTP proxy or a load balancer.
req.Header.Add("X-Forwarded-Host", req.Host)
director(req)
req.Host = to.Host
}
return proxy
}
// newRouteSigner creates a route specific signer.
func (p *Proxy) newRouteSigner(audience string) (cryptutil.JWTSigner, error) {
decodedSigningKey, err := base64.StdEncoding.DecodeString(p.signingKey)
if err != nil {
return nil, err
}
return cryptutil.NewES256Signer(decodedSigningKey, audience)
}
func (p *Proxy) customCAPool(cert string) (*x509.CertPool, error) {
certPool := x509.NewCertPool()
decodedCert, err := base64.StdEncoding.DecodeString(cert)
if err != nil {
return nil, fmt.Errorf("failed to decode cert: %s", err)
}
if ok := certPool.AppendCertsFromPEM(decodedCert); !ok {
return nil, fmt.Errorf("could not append cert: %s", decodedCert)
}
return certPool, nil
}
// newReverseProxyHandler applies handler specific options to a given route.
func (p *Proxy) newReverseProxyHandler(rp *httputil.ReverseProxy, route *config.Policy) (handler http.Handler, err error) {
handler = &UpstreamProxy{
name: route.Destination.Host,
handler: rp,
}
c := middleware.NewChain()
c = c.Append(middleware.StripPomeriumCookie(p.cookieName))
// if signing key is set, add signer to middleware
if len(p.signingKey) != 0 {
signer, err := p.newRouteSigner(route.Source.Host)
if err != nil {
return nil, err
}
c = c.Append(middleware.SignRequest(signer, HeaderUserID, HeaderEmail, HeaderGroups, HeaderJWT))
}
// websockets cannot use the non-hijackable timeout-handler
if !route.AllowWebsockets {
timeout := p.defaultUpstreamTimeout
if route.UpstreamTimeout != 0 {
timeout = route.UpstreamTimeout
}
timeoutMsg := fmt.Sprintf("%s failed to respond within the %s timeout period", route.Destination.Host, timeout)
handler = http.TimeoutHandler(handler, timeout, timeoutMsg)
}
return c.Then(handler), nil
}
// UpdateOptions updates internal structures based on config.Options
func (p *Proxy) UpdateOptions(o config.Options) error {
return p.UpdatePolicies(&o)
}