New flag "-ssl-upstream-insecure-skip-validation" (#234)

* New flag "-ssl-upstream-insecure-skip-validation" to skip SSL validation for upstreams with self generated / invalid SSL certificates.

* Fix tests for modified NewReverseProxy method.

* Added change to the changelog.

* Remove duplicate entries from changelog.

CHANGELOG.md

@@ -36,6 +36,7 @@
 
 ## Changes since v3.2.0
 
+- [#234](https://github.com/pusher/oauth2_proxy/pull/234) Added option `-ssl-upstream-insecure-skip-validation` to skip validation of upstream SSL certificates (@jansinger)
 - [#224](https://github.com/pusher/oauth2_proxy/pull/224) Check Google group membership using hasMember to support nested groups and external users (@jpalpant)
 - [#231](https://github.com/pusher/oauth2_proxy/pull/231) Add optional group membership and email domain checks to the GitLab provider (@Overv)
 - [#178](https://github.com/pusher/outh2_proxy/pull/178) Add Silence Ping Logging and Exclude Logging Paths flags (@kskewes)

docs/configuration/configuration.md

@@ -99,7 +99,8 @@ Usage of oauth2_proxy:
   -skip-jwt-bearer-tokens: will skip requests that have verified JWT bearer tokens
   -skip-oidc-discovery: bypass OIDC endpoint discovery. login-url, redeem-url and oidc-jwks-url must be configured in this case
   -skip-provider-button: will skip sign-in-page to directly reach the next step: oauth/start
-  -ssl-insecure-skip-verify: skip validation of certificates presented when using HTTPS
+  -ssl-insecure-skip-verify: skip validation of certificates presented when using HTTPS providers
+  -ssl-upstream-insecure-skip-verify: skip validation of certificates presented when using HTTPS upstreams
   -standard-logging: Log standard runtime information (default true)
   -standard-logging-format string: Template for standard log lines (see "Logging Configuration" paragraph below)
   -tls-cert-file string: path to certificate file

main.go

@@ -47,7 +47,8 @@ func main() {
 	flagSet.Var(&skipAuthRegex, "skip-auth-regex", "bypass authentication for requests path's that match (may be given multiple times)")
 	flagSet.Bool("skip-provider-button", false, "will skip sign-in-page to directly reach the next step: oauth/start")
 	flagSet.Bool("skip-auth-preflight", false, "will skip authentication for OPTIONS requests")
-	flagSet.Bool("ssl-insecure-skip-verify", false, "skip validation of certificates presented when using HTTPS")
+	flagSet.Bool("ssl-insecure-skip-verify", false, "skip validation of certificates presented when using HTTPS providers")
+	flagSet.Bool("ssl-upstream-insecure-skip-verify", false, "skip validation of certificates presented when using HTTPS upstreams")
 	flagSet.Duration("flush-interval", time.Duration(1)*time.Second, "period between response flushing when streaming responses")
 	flagSet.Bool("skip-jwt-bearer-tokens", false, "will skip requests that have verified JWT bearer tokens (default false)")
 	flagSet.Var(&jwtIssuers, "extra-jwt-issuers", "if skip-jwt-bearer-tokens is set, a list of extra JWT issuer=audience pairs (where the issuer URL has a .well-known/openid-configuration or a .well-known/jwks.json)")

oauthproxy.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"crypto/tls"
 	b64 "encoding/base64"
 	"errors"
 	"fmt"
@@ -128,9 +129,14 @@ func (u *UpstreamProxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 
 // NewReverseProxy creates a new reverse proxy for proxying requests to upstream
 // servers
-func NewReverseProxy(target *url.URL, flushInterval time.Duration) (proxy *httputil.ReverseProxy) {
+func NewReverseProxy(target *url.URL, opts *Options) (proxy *httputil.ReverseProxy) {
 	proxy = httputil.NewSingleHostReverseProxy(target)
-	proxy.FlushInterval = flushInterval
+	proxy.FlushInterval = opts.FlushInterval
+	if opts.SSLUpstreamInsecureSkipVerify {
+		proxy.Transport = &http.Transport{
+			TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
+		}
+	}
 	return proxy
 }
 
@@ -163,7 +169,7 @@ func NewFileServer(path string, filesystemPath string) (proxy http.Handler) {
 // NewWebSocketOrRestReverseProxy creates a reverse proxy for REST or websocket based on url
 func NewWebSocketOrRestReverseProxy(u *url.URL, opts *Options, auth hmacauth.HmacAuth) http.Handler {
 	u.Path = ""
-	proxy := NewReverseProxy(u, opts.FlushInterval)
+	proxy := NewReverseProxy(u, opts)
 	if !opts.PassHostHeader {
 		setProxyUpstreamHostHeader(proxy, u)
 	} else {

oauthproxy_test.go

@@ -122,7 +122,7 @@ func TestNewReverseProxy(t *testing.T) {
 	backendHost := net.JoinHostPort(backendHostname, backendPort)
 	proxyURL, _ := url.Parse(backendURL.Scheme + "://" + backendHost + "/")
 
-	proxyHandler := NewReverseProxy(proxyURL, time.Second)
+	proxyHandler := NewReverseProxy(proxyURL, &Options{FlushInterval: time.Second})
 	setProxyUpstreamHostHeader(proxyHandler, proxyURL)
 	frontend := httptest.NewServer(proxyHandler)
 	defer frontend.Close()
@@ -144,7 +144,7 @@ func TestEncodedSlashes(t *testing.T) {
 	defer backend.Close()
 
 	b, _ := url.Parse(backend.URL)
-	proxyHandler := NewReverseProxy(b, time.Second)
+	proxyHandler := NewReverseProxy(b, &Options{FlushInterval: time.Second})
 	setProxyDirector(proxyHandler)
 	frontend := httptest.NewServer(proxyHandler)
 	defer frontend.Close()

options.go

@@ -73,6 +73,7 @@ type Options struct {
 	SkipProviderButton            bool          `flag:"skip-provider-button" cfg:"skip_provider_button" env:"OAUTH2_PROXY_SKIP_PROVIDER_BUTTON"`
 	PassUserHeaders               bool          `flag:"pass-user-headers" cfg:"pass_user_headers" env:"OAUTH2_PROXY_PASS_USER_HEADERS"`
 	SSLInsecureSkipVerify         bool          `flag:"ssl-insecure-skip-verify" cfg:"ssl_insecure_skip_verify" env:"OAUTH2_PROXY_SSL_INSECURE_SKIP_VERIFY"`
+	SSLUpstreamInsecureSkipVerify bool          `flag:"ssl-upstream-insecure-skip-verify" cfg:"ssl_upstream_insecure_skip_verify" env:"OAUTH2_PROXY_SSL_UPSTREAM_INSECURE_SKIP_VERIFY"`
 	SetXAuthRequest               bool          `flag:"set-xauthrequest" cfg:"set_xauthrequest" env:"OAUTH2_PROXY_SET_XAUTHREQUEST"`
 	SetAuthorization              bool          `flag:"set-authorization-header" cfg:"set_authorization_header" env:"OAUTH2_PROXY_SET_AUTHORIZATION_HEADER"`
 	PassAuthorization             bool          `flag:"pass-authorization-header" cfg:"pass_authorization_header" env:"OAUTH2_PROXY_PASS_AUTHORIZATION_HEADER"`