Adding TLS client cert placeholders (#2217)

* Adding TLS client cert placeholders

* Use function to get the peer certificate

* Changing SHA1 to SHA256

* Use UTC instead of GMT

* Adding tests

* Adding getters for Protocol and Cipher

caddyhttp/httpserver/replacer.go

@@ -16,6 +16,10 @@ package httpserver
 
 import (
 	"bytes"
+	"crypto/sha256"
+	"crypto/x509"
+	"encoding/pem"
+	"fmt"
 	"io"
 	"io/ioutil"
 	"net"
@@ -243,6 +247,15 @@ func round(d, r time.Duration) time.Duration {
 	return d
 }
 
+// getPeerCert returns peer certificate
+func (r *replacer) getPeerCert() *x509.Certificate {
+	if r.request.TLS != nil && len(r.request.TLS.PeerCertificates) > 0 {
+		return r.request.TLS.PeerCertificates[0]
+	}
+
+	return nil
+}
+
 // getSubstitution retrieves value from corresponding key
 func (r *replacer) getSubstitution(key string) string {
 	// search custom replacements first
@@ -413,22 +426,80 @@ func (r *replacer) getSubstitution(key string) string {
 		return strconv.FormatInt(convertToMilliseconds(elapsedDuration), 10)
 	case "{tls_protocol}":
 		if r.request.TLS != nil {
-			for k, v := range caddytls.SupportedProtocols {
-				if v == r.request.TLS.Version {
-					return k
-				}
-			}
+			if name, err := caddytls.GetSupportedProtocolName(r.request.TLS.Version); err == nil {
+				return name
+			} else {
 				return "tls" // this should never happen, but guard in case
 			}
+		}
 		return r.emptyValue // because not using a secure channel
 	case "{tls_cipher}":
 		if r.request.TLS != nil {
-			for k, v := range caddytls.SupportedCiphersMap {
-				if v == r.request.TLS.CipherSuite {
-					return k
+			if name, err := caddytls.GetSupportedCipherName(r.request.TLS.CipherSuite); err == nil {
+				return name
+			} else {
+				return "UNKNOWN" // this should never happen, but guard in case
 			}
 		}
-			return "UNKNOWN" // this should never happen, but guard in case
+		return r.emptyValue
+	case "{tls_client_escaped_cert}":
+		cert := r.getPeerCert()
+		if cert != nil {
+			pemBlock := pem.Block{
+				Type:  "CERTIFICATE",
+				Bytes: cert.Raw,
+			}
+			return url.QueryEscape(string(pem.EncodeToMemory(&pemBlock)))
+		}
+		return r.emptyValue
+	case "{tls_client_fingerprint}":
+		cert := r.getPeerCert()
+		if cert != nil {
+			return fmt.Sprintf("%x", sha256.Sum256(cert.Raw))
+		}
+		return r.emptyValue
+	case "{tls_client_i_dn}":
+		cert := r.getPeerCert()
+		if cert != nil {
+			return cert.Issuer.String()
+		}
+		return r.emptyValue
+	case "{tls_client_raw_cert}":
+		cert := r.getPeerCert()
+		if cert != nil {
+			return string(cert.Raw)
+		}
+		return r.emptyValue
+	case "{tls_client_s_dn}":
+		cert := r.getPeerCert()
+		if cert != nil {
+			return cert.Subject.String()
+		}
+		return r.emptyValue
+	case "{tls_client_serial}":
+		cert := r.getPeerCert()
+		if cert != nil {
+			return fmt.Sprintf("%x", cert.SerialNumber)
+		}
+		return r.emptyValue
+	case "{tls_client_v_end}":
+		cert := r.getPeerCert()
+		if cert != nil {
+			return cert.NotAfter.In(time.UTC).Format("Jan 02 15:04:05 2006 MST")
+		}
+		return r.emptyValue
+	case "{tls_client_v_remain}":
+		cert := r.getPeerCert()
+		if cert != nil {
+			now := time.Now().In(time.UTC)
+			days := int64(cert.NotAfter.Sub(now).Seconds() / 86400)
+			return strconv.FormatInt(days, 10)
+		}
+		return r.emptyValue
+	case "{tls_client_v_start}":
+		cert := r.getPeerCert()
+		if cert != nil {
+			return cert.NotBefore.Format("Jan 02 15:04:05 2006 MST")
 		}
 		return r.emptyValue
 	default:

caddyhttp/httpserver/replacer_test.go

@@ -16,12 +16,21 @@ package httpserver
 
 import (
 	"context"
+	"crypto/sha256"
+	"crypto/tls"
+	"crypto/x509"
+	"encoding/pem"
+	"fmt"
 	"net/http"
 	"net/http/httptest"
+	"net/url"
 	"os"
+	"strconv"
 	"strings"
 	"testing"
 	"time"
+
+	"github.com/mholt/caddy/caddytls"
 )
 
 func TestNewReplacer(t *testing.T) {
@@ -147,6 +156,102 @@ func TestReplace(t *testing.T) {
 	}
 }
 
+func TestTlsReplace(t *testing.T) {
+	w := httptest.NewRecorder()
+	recordRequest := NewResponseRecorder(w)
+
+	clientCertText := []byte(`-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`)
+
+	block, _ := pem.Decode(clientCertText)
+	if block == nil {
+		t.Fatalf("failed to decode PEM certificate")
+	}
+
+	cert, err := x509.ParseCertificate(block.Bytes)
+	if err != nil {
+		t.Fatalf("failed to decode PEM certificate: %v", err)
+	}
+
+	request := &http.Request{
+		Method: "GET",
+		Host:   "foo.com",
+		URL: &url.URL{
+			Scheme: "https",
+			Path:   "/path/",
+			Host:   "foo.com",
+		},
+		Header:     http.Header{},
+		Proto:      "HTTP/1.1",
+		ProtoMajor: 1,
+		ProtoMinor: 1,
+		RemoteAddr: "192.0.2.1:1234",
+		RequestURI: "https://foo.com/path/",
+		TLS: &tls.ConnectionState{
+			Version:           tls.VersionTLS12,
+			HandshakeComplete: true,
+			ServerName:        "foo.com",
+			CipherSuite:       tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+			PeerCertificates:  []*x509.Certificate{cert},
+		},
+	}
+
+	repl := NewReplacer(request, recordRequest, "-")
+
+	now := time.Now().In(time.UTC)
+	days := int64(cert.NotAfter.Sub(now).Seconds() / 86400)
+	pemBlock := pem.Block{
+		Type:  "CERTIFICATE",
+		Bytes: cert.Raw,
+	}
+
+	protocol, _ := caddytls.GetSupportedProtocolName(request.TLS.Version)
+	cipher, _ := caddytls.GetSupportedCipherName(request.TLS.CipherSuite)
+	cEscapedCert := url.QueryEscape(string(pem.EncodeToMemory(&pemBlock)))
+	cFingerprint := fmt.Sprintf("%x", sha256.Sum256(cert.Raw))
+	cIDn := cert.Issuer.String()
+	cRawCert := string(cert.Raw)
+	cSDn := cert.Subject.String()
+	cSerial := fmt.Sprintf("%x", cert.SerialNumber)
+	cVEnd := cert.NotAfter.In(time.UTC).Format("Jan 02 15:04:05 2006 MST")
+	cVRemain := strconv.FormatInt(days, 10)
+	cVStart := cert.NotBefore.Format("Jan 02 15:04:05 2006 MST")
+
+	testCases := []struct {
+		template string
+		expect   string
+	}{
+		{"{tls_protocol}", protocol},
+		{"{tls_cipher}", cipher},
+		{"{tls_client_escaped_cert}", cEscapedCert},
+		{"{tls_client_fingerprint}", cFingerprint},
+		{"{tls_client_i_dn}", cIDn},
+		{"{tls_client_raw_cert}", cRawCert},
+		{"{tls_client_s_dn}", cSDn},
+		{"{tls_client_serial}", cSerial},
+		{"{tls_client_v_end}", cVEnd},
+		{"{tls_client_v_remain}", cVRemain},
+		{"{tls_client_v_start}", cVStart},
+	}
+
+	for _, c := range testCases {
+		if expected, actual := c.expect, repl.Replace(c.template); expected != actual {
+			t.Errorf("for template '%s', expected '%s', got '%s'", c.template, expected, actual)
+		}
+	}
+}
+
 func BenchmarkReplace(b *testing.B) {
 	w := httptest.NewRecorder()
 	recordRequest := NewResponseRecorder(w)

caddytls/config.go

@@ -17,6 +17,7 @@ package caddytls
 import (
 	"crypto/tls"
 	"crypto/x509"
+	"errors"
 	"fmt"
 	"io/ioutil"
 
@@ -584,6 +585,17 @@ var SupportedProtocols = map[string]uint16{
 	"tls1.2": tls.VersionTLS12,
 }
 
+// GetSupportedProtocolName returns the protocol name
+func GetSupportedProtocolName(protocol uint16) (string, error) {
+	for k, v := range SupportedProtocols {
+		if v == protocol {
+			return k, nil
+		}
+	}
+
+	return "", errors.New("name: unsuported protocol")
+}
+
 // Map of supported ciphers, used only for parsing config.
 //
 // Note that, at time of writing, HTTP/2 blacklists 276 cipher suites,
@@ -611,6 +623,17 @@ var SupportedCiphersMap = map[string]uint16{
 	"RSA-3DES-EDE-CBC-SHA":               tls.TLS_RSA_WITH_3DES_EDE_CBC_SHA,
 }
 
+// GetSupportedCipherName returns the cipher name
+func GetSupportedCipherName(cipher uint16) (string, error) {
+	for k, v := range SupportedCiphersMap {
+		if v == cipher {
+			return k, nil
+		}
+	}
+
+	return "", errors.New("name: unsuported cipher")
+}
+
 // List of all the ciphers we want to use by default
 var defaultCiphers = []uint16{
 	tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,