enhance: support client certificates for mutual TLS (#1273)

Add `runner.client_cert_file` and `runner.client_key_file` for Gitea instances that require mutual TLS. The runner presents the certificate on its RPCs, job summary uploads, and the action, reusable workflow and `builtin:checkout` clones from the instance. The files are read on use, so renewed certificates apply without a restart. Job steps do not get them. An incomplete or mismatched pair fails startup.

Clones now decide the token, client certificate and `runner.insecure` with one host check, which also gives reusable workflow clones the TLS settings they lacked. `runner.insecure` still only covers the registered address.

Fixes: https://gitea.com/gitea/runner/issues/321
Co-authored-by: silverwind <[email protected]>
Co-authored-by: silverwind <[email protected]>
Reviewed-on: https://gitea.com/gitea/runner/pulls/1273
Reviewed-by: silverwind <[email protected]>
Co-authored-by: bircni <[email protected]>

internal/pkg/client/http_test.go

@@ -4,6 +4,7 @@
 package client
 
 import (
+	"crypto/tls"
 	"net"
 	"net/http"
 	"net/http/httptest"
@@ -20,7 +21,7 @@ import (
 func TestGetHTTPClientUsesProxyFromEnvironment(t *testing.T) {
 	t.Setenv("HTTP_PROXY", "http://proxy.example.com:8080")
 
-	client := getHTTPClient("http://gitea.example.com", false, time.Minute, nil)
+	client := getHTTPClient("http://gitea.example.com", nil, time.Minute, nil)
 	require.Equal(t, time.Minute, client.Timeout)
 	transport, ok := client.Transport.(*http.Transport)
 	require.True(t, ok)
@@ -34,29 +35,10 @@ func TestGetHTTPClientUsesProxyFromEnvironment(t *testing.T) {
 	require.Equal(t, "http://proxy.example.com:8080", proxyURL.String())
 }
 
-func TestGetHTTPClientInsecureTLS(t *testing.T) {
-	// insecure only takes effect for https endpoints
-	httpsInsecure := getHTTPClient("https://gitea.example.com", true, time.Minute, nil)
-	transport, ok := httpsInsecure.Transport.(*http.Transport)
-	require.True(t, ok)
-	require.NotNil(t, transport.TLSClientConfig)
-	require.True(t, transport.TLSClientConfig.InsecureSkipVerify)
-
-	for _, tc := range []struct {
-		name     string
-		endpoint string
-		insecure bool
-	}{
-		{"https secure", "https://gitea.example.com", false},
-		{"http insecure ignored", "http://gitea.example.com", true},
-	} {
-		t.Run(tc.name, func(t *testing.T) {
-			c := getHTTPClient(tc.endpoint, tc.insecure, time.Minute, nil)
-			tr, ok := c.Transport.(*http.Transport)
-			require.True(t, ok)
-			require.Nil(t, tr.TLSClientConfig)
-		})
-	}
+func TestGetHTTPClientAppliesTLSConfigOnlyToHTTPS(t *testing.T) {
+	tlsConfig := &tls.Config{}
+	require.Same(t, tlsConfig, getHTTPClient("https://gitea.example.com", tlsConfig, time.Minute, nil).Transport.(*http.Transport).TLSClientConfig)
+	require.Nil(t, getHTTPClient("http://gitea.example.com", tlsConfig, time.Minute, nil).Transport.(*http.Transport).TLSClientConfig)
 }
 
 func TestNewSetsBaseURLAndHeaders(t *testing.T) {
@@ -70,7 +52,7 @@ func TestNewSetsBaseURLAndHeaders(t *testing.T) {
 	defer server.Close()
 
 	// trailing slash must be trimmed before "/api/actions" is appended
-	c := New(server.URL+"/", false, "the-uuid", "the-token", time.Minute, map[string]string{
+	c := New(server.URL+"/", nil, "the-uuid", "the-token", time.Minute, map[string]string{
 		"X-Proxy-Token":      "proxy-token",
 		protocol.UUIDHeader:  "other-uuid",
 		protocol.TokenHeader: "other-token",
@@ -97,7 +79,7 @@ func TestNewOmitsEmptyHeaders(t *testing.T) {
 	}))
 	defer server.Close()
 
-	c := New(server.URL, false, "", "", time.Minute, nil)
+	c := New(server.URL, nil, "", "", time.Minute, nil)
 	_, _ = c.Ping(t.Context(), connect.NewRequest(&pingv1.PingRequest{Data: "hi"}))
 
 	require.Empty(t, gotHeaders.Get(protocol.UUIDHeader))
@@ -110,7 +92,7 @@ func TestNewStopsRedirectLoop(t *testing.T) {
 	}))
 	defer server.Close()
 
-	c := New(server.URL, false, "", "", time.Minute, nil)
+	c := New(server.URL, nil, "", "", time.Minute, nil)
 	_, err := c.Ping(t.Context(), connect.NewRequest(&pingv1.PingRequest{Data: "hi"}))
 	require.ErrorContains(t, err, "stopped after 10 redirects")
 }
@@ -136,7 +118,7 @@ func TestNewRedirectKeepsExtraHeadersOnlyOnSameHost(t *testing.T) {
 	} {
 		gotHeaders = nil
 		origin := tc.newOrigin(http.RedirectHandler("http://"+net.JoinHostPort(tc.host, port), http.StatusPermanentRedirect))
-		c := New(origin.URL, true, "the-uuid", "the-token", time.Minute, map[string]string{"X-Proxy-Token": "proxy-token", "Content-Type": "text/plain"})
+		c := New(origin.URL, &tls.Config{InsecureSkipVerify: true}, "the-uuid", "the-token", time.Minute, map[string]string{"X-Proxy-Token": "proxy-token", "Content-Type": "text/plain"})
 		_, _ = c.Ping(t.Context(), connect.NewRequest(&pingv1.PingRequest{Data: "hi"}))
 		origin.Close()