gitlab: support custom rootCAData

Signed-off-by: Ivan Zvyagintsev <ivan.zvyagintsev@flant.com>

connector/gitlab/gitlab.go

@@ -10,12 +10,14 @@ import (
 	"log/slog"
 	"net/http"
 	"strconv"
+	"strings"
 	"time"
 
 	"golang.org/x/oauth2"
 
 	"github.com/dexidp/dex/connector"
 	"github.com/dexidp/dex/pkg/groups"
+	"github.com/dexidp/dex/pkg/httpclient"
 )
 
 const (
@@ -35,6 +37,7 @@ type Config struct {
 	Groups              []string `json:"groups"`
 	UseLoginAsID        bool     `json:"useLoginAsID"`
 	GetGroupsPermission bool     `json:"getGroupsPermission"`
+	RootCAData          []byte   `json:"rootCAData,omitempty"`
 }
 
 type gitlabUser struct {
@@ -51,6 +54,19 @@ func (c *Config) Open(id string, logger *slog.Logger) (connector.Connector, erro
 	if c.BaseURL == "" {
 		c.BaseURL = "https://gitlab.com"
 	}
+	var httpClient *http.Client
+	if len(c.RootCAData) > 0 {
+		var err error
+		httpClient, err = httpclient.NewHTTPClient([]string{string(c.RootCAData)}, false)
+		if err != nil {
+			// Keep backward-compatible error semantics for invalid PEM input.
+			if strings.Contains(err.Error(), "not in PEM format") {
+				return nil, fmt.Errorf("gitlab: invalid rootCAData")
+			}
+			return nil, fmt.Errorf("gitlab: failed to create HTTP client: %v", err)
+		}
+		httpClient.Timeout = 30 * time.Second
+	}
 	return &gitlabConnector{
 		baseURL:             c.BaseURL,
 		redirectURI:         c.RedirectURI,
@@ -60,6 +76,7 @@ func (c *Config) Open(id string, logger *slog.Logger) (connector.Connector, erro
 		groups:              c.Groups,
 		useLoginAsID:        c.UseLoginAsID,
 		getGroupsPermission: c.GetGroupsPermission,
+		httpClient:          httpClient,
 	}, nil
 }
 

connector/gitlab/gitlab_test.go

@@ -4,15 +4,178 @@ import (
 	"context"
 	"crypto/tls"
 	"encoding/json"
+	"fmt"
+	"io"
+	"log/slog"
 	"net/http"
 	"net/http/httptest"
 	"net/url"
+	"os"
 	"reflect"
+	"strings"
 	"testing"
+	"time"
 
 	"github.com/dexidp/dex/connector"
 )
 
+func readValidRootCAData(t *testing.T) []byte {
+	t.Helper()
+	b, err := os.ReadFile("testdata/rootCA.pem")
+	if err != nil {
+		t.Fatalf("failed to read rootCA.pem testdata: %v", err)
+	}
+	return b
+}
+
+func newLocalHTTPSTestServer(t *testing.T, handler http.Handler) *httptest.Server {
+	t.Helper()
+
+	ts := httptest.NewUnstartedServer(handler)
+	cert, err := tls.LoadX509KeyPair("testdata/server.crt", "testdata/server.key")
+	if err != nil {
+		t.Fatalf("failed to load TLS test cert/key: %v", err)
+	}
+	ts.TLS = &tls.Config{Certificates: []tls.Certificate{cert}}
+	ts.StartTLS()
+	return ts
+}
+
+func TestOpenWithRootCADataCreatesHTTPClient(t *testing.T) {
+	logger := slog.New(slog.NewTextHandler(io.Discard, nil))
+
+	cfg := &Config{
+		RootCAData: readValidRootCAData(t),
+	}
+
+	conn, err := cfg.Open("test", logger)
+	if err != nil {
+		t.Fatalf("expected nil error, got %v", err)
+	}
+
+	gc, ok := conn.(*gitlabConnector)
+	if !ok {
+		t.Fatalf("expected *gitlabConnector, got %T", conn)
+	}
+	if gc.httpClient == nil {
+		t.Fatalf("expected httpClient to be non-nil")
+	}
+	if gc.httpClient.Timeout != 30*time.Second {
+		t.Fatalf("expected httpClient timeout %v, got %v", 30*time.Second, gc.httpClient.Timeout)
+	}
+	tr, ok := gc.httpClient.Transport.(*http.Transport)
+	if !ok {
+		t.Fatalf("expected transport to be *http.Transport, got %T", gc.httpClient.Transport)
+	}
+	// ProxyFromEnvironment is expected to be enabled (non-nil proxy func).
+	if tr.Proxy == nil {
+		t.Fatalf("expected transport.Proxy to be set (ProxyFromEnvironment)")
+	}
+	if tr.TLSClientConfig == nil || tr.TLSClientConfig.RootCAs == nil {
+		t.Fatalf("expected transport TLS root CAs to be configured")
+	}
+}
+
+func TestOpenWithInvalidRootCADataReturnsError(t *testing.T) {
+	logger := slog.New(slog.NewTextHandler(io.Discard, nil))
+
+	cfg := &Config{
+		RootCAData: []byte("not a pem"),
+	}
+
+	_, err := cfg.Open("test", logger)
+	if err == nil {
+		t.Fatalf("expected error, got nil")
+	}
+	if !strings.Contains(err.Error(), "invalid rootCAData") {
+		t.Fatalf("expected error to contain %q, got %q", "invalid rootCAData", err.Error())
+	}
+}
+
+func TestHandleCallbackCustomRootCADataEnablesTLSRequests(t *testing.T) {
+	logger := slog.New(slog.NewTextHandler(io.Discard, nil))
+
+	ts := newLocalHTTPSTestServer(t, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Add("Content-Type", "application/json")
+		switch r.URL.Path {
+		case "/oauth/token":
+			// oauth2.Exchange expects an access token in response.
+			fmt.Fprint(w, `{"access_token":"abc","token_type":"bearer","expires_in":30}`)
+		case "/api/v4/user":
+			json.NewEncoder(w).Encode(gitlabUser{Email: "some@email.com", ID: 12345678})
+		default:
+			http.NotFound(w, r)
+		}
+	}))
+	defer ts.Close()
+
+	cfg := &Config{
+		BaseURL:      ts.URL,
+		ClientID:     "client-id",
+		ClientSecret: "client-secret",
+		RedirectURI:  "https://example.invalid/callback",
+		RootCAData:   readValidRootCAData(t),
+	}
+
+	conn, err := cfg.Open("test", logger)
+	if err != nil {
+		t.Fatalf("Open() error: %v", err)
+	}
+
+	hostURL, err := url.Parse(ts.URL)
+	expectNil(t, err)
+	req, err := http.NewRequest("GET", hostURL.String()+"?code=testcode", nil)
+	expectNil(t, err)
+
+	identity, err := conn.(connector.CallbackConnector).HandleCallback(connector.Scopes{Groups: false}, req)
+	if err != nil {
+		t.Fatalf("HandleCallback() error: %v", err)
+	}
+	if identity.Email != "some@email.com" || identity.UserID != "12345678" {
+		t.Fatalf("unexpected identity: %#v", identity)
+	}
+}
+
+func TestHandleCallbackWithoutRootCADataFailsTLS(t *testing.T) {
+	logger := slog.New(slog.NewTextHandler(io.Discard, nil))
+
+	ts := newLocalHTTPSTestServer(t, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Add("Content-Type", "application/json")
+		switch r.URL.Path {
+		case "/oauth/token":
+			fmt.Fprint(w, `{"access_token":"abc","token_type":"bearer","expires_in":30}`)
+		case "/api/v4/user":
+			json.NewEncoder(w).Encode(gitlabUser{Email: "some@email.com", ID: 12345678})
+		default:
+			http.NotFound(w, r)
+		}
+	}))
+	defer ts.Close()
+
+	cfg := &Config{
+		BaseURL:      ts.URL,
+		ClientID:     "client-id",
+		ClientSecret: "client-secret",
+		RedirectURI:  "https://example.invalid/callback",
+		// RootCAData intentionally omitted: should fail TLS verification against our custom server cert.
+	}
+
+	conn, err := cfg.Open("test", logger)
+	if err != nil {
+		t.Fatalf("Open() error: %v", err)
+	}
+
+	hostURL, err := url.Parse(ts.URL)
+	expectNil(t, err)
+	req, err := http.NewRequest("GET", hostURL.String()+"?code=testcode", nil)
+	expectNil(t, err)
+
+	_, err = conn.(connector.CallbackConnector).HandleCallback(connector.Scopes{Groups: false}, req)
+	if err == nil {
+		t.Fatalf("expected TLS error, got nil")
+	}
+}
+
 func TestUserGroups(t *testing.T) {
 	s := newTestServer(map[string]interface{}{
 		"/oauth/userinfo": userInfo{

connector/gitlab/testdata/rootCA.pem

@@ -0,0 +1,23 @@
+-----BEGIN CERTIFICATE-----
+MIID1jCCAr4CCQCG4JBeSi6cDjANBgkqhkiG9w0BAQsFADCBrDELMAkGA1UEBhMC
+VVMxFDASBgNVBAgMC1JhbmRvbVN0YXRlMRMwEQYDVQQHDApSYW5kb21DaXR5MRsw
+GQYDVQQKDBJSYW5kb21Pcmdhbml6YXRpb24xHzAdBgNVBAsMFlJhbmRvbU9yZ2Fu
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+QGV4YW1wbGUuY29tMRIwEAYDVQQDDAlsb2NhbGhvc3QwggEiMA0GCSqGSIb3DQEB
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+GSzZKrqX+TSIgpPrLYNHX4uxlo5TAwP/5GM=
+-----END CERTIFICATE-----

connector/gitlab/testdata/server.crt

@@ -0,0 +1,29 @@
+-----BEGIN CERTIFICATE-----
+MIIE5TCCA82gAwIBAgIJAMGzXwBRpkG7MA0GCSqGSIb3DQEBCwUAMIGsMQswCQYD
+VQQGEwJVUzEUMBIGA1UECAwLUmFuZG9tU3RhdGUxEzARBgNVBAcMClJhbmRvbUNp
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+OkuFKp+VjxQX
+-----END CERTIFICATE-----

connector/gitlab/testdata/server.key

@@ -0,0 +1,28 @@
+-----BEGIN PRIVATE KEY-----
+MIIEvQIBADANBgkqhkiG9w0BAQEFAASCBKcwggSjAgEAAoIBAQDLinaVz/O0OyoN
+4mn187wblSMldSuVJjGIjZKM7ZAuV6wsx2kEUvwqCG+/51KprQMce0S9I84Wfd8w
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+ouTtnC3TgmcjhTgGmb48QQE=
+-----END PRIVATE KEY-----