httpcaddyfile: Add client_auth options to tls directive (#3335)

* reading client certificate config from Caddyfile

Signed-off-by: NWHirschfeld <Niclas@NWHirschfeld.de>

* Update caddyconfig/httpcaddyfile/builtins.go

Co-authored-by: Francis Lavoie <lavofr@gmail.com>

* added adapt test for parsing client certificate configuration from Caddyfile

Signed-off-by: NWHirschfeld <Niclas@NWHirschfeld.de>

* read client ca and leaf certificates from file https://github.com/caddyserver/caddy/pull/3335#discussion_r421633844

Signed-off-by: NWHirschfeld <Niclas@NWHirschfeld.de>

* Update modules/caddytls/connpolicy.go

* Make review adjustments

Co-authored-by: Francis Lavoie <lavofr@gmail.com>
Co-authored-by: Matt Holt <mholt@users.noreply.github.com>

5 files changed, 215 insertions, 8 deletions

diff --git a/caddyconfig/httpcaddyfile/builtins.go b/caddyconfig/httpcaddyfile/builtins.go
index 90ce3a4..fde5601 100644
--- a/caddyconfig/httpcaddyfile/builtins.go
+++ b/caddyconfig/httpcaddyfile/builtins.go
@@ -15,8 +15,11 @@
 package httpcaddyfile
 
 import (
+	"encoding/base64"
+	"encoding/pem"
 	"fmt"
 	"html"
+	"io/ioutil"
 	"net/http"
 	"reflect"
 	"strings"
@@ -59,6 +62,13 @@ func parseBind(h Helper) ([]ConfigValue, error) {
 //         protocols <min> [<max>]
 //         ciphers   <cipher_suites...>
 //         curves    <curves...>
+//         client_auth {
+//             mode                   [request|require|verify_if_given|require_and_verify]
+//             trusted_ca_cert        <base64_der>
+//             trusted_ca_cert_file   <filename>
+//             trusted_leaf_cert      <base64_der>
+//             trusted_leaf_cert_file <filename>
+//         }
 //         alpn      <values...>
 //         load      <paths...>
 //         ca        <acme_ca_endpoint>
@@ -143,7 +153,7 @@ func parseTLS(h Helper) ([]ConfigValue, error) {
 		}
 
 		var hasBlock bool
-		for h.NextBlock(0) {
+		for nesting := h.Nesting(); h.NextBlock(nesting); {
 			hasBlock = true
 
 			switch h.Val() {
@@ -181,6 +191,57 @@ func parseTLS(h Helper) ([]ConfigValue, error) {
 					cp.Curves = append(cp.Curves, h.Val())
 				}
 
+			case "client_auth":
+				cp.ClientAuthentication = &caddytls.ClientAuthentication{}
+				for nesting := h.Nesting(); h.NextBlock(nesting); {
+					subdir := h.Val()
+					switch subdir {
+					case "mode":
+						if !h.Args(&cp.ClientAuthentication.Mode) {
+							return nil, h.ArgErr()
+						}
+						if h.NextArg() {
+							return nil, h.ArgErr()
+						}
+
+					case "trusted_ca_cert",
+						"trusted_leaf_cert":
+						if !h.NextArg() {
+							return nil, h.ArgErr()
+						}
+						if subdir == "trusted_ca_cert" {
+							cp.ClientAuthentication.TrustedCACerts = append(cp.ClientAuthentication.TrustedCACerts, h.Val())
+						} else {
+							cp.ClientAuthentication.TrustedLeafCerts = append(cp.ClientAuthentication.TrustedLeafCerts, h.Val())
+						}
+
+					case "trusted_ca_cert_file",
+						"trusted_leaf_cert_file":
+						if !h.NextArg() {
+							return nil, h.ArgErr()
+						}
+						filename := h.Val()
+						certDataPEM, err := ioutil.ReadFile(filename)
+						if err != nil {
+							return nil, err
+						}
+						block, _ := pem.Decode(certDataPEM)
+						if block == nil || block.Type != "CERTIFICATE" {
+							return nil, h.Errf("no CERTIFICATE pem block found in %s", h.Val())
+						}
+						if subdir == "trusted_ca_cert_file" {
+							cp.ClientAuthentication.TrustedCACerts = append(cp.ClientAuthentication.TrustedCACerts,
+								base64.StdEncoding.EncodeToString(block.Bytes))
+						} else {
+							cp.ClientAuthentication.TrustedLeafCerts = append(cp.ClientAuthentication.TrustedLeafCerts,
+								base64.StdEncoding.EncodeToString(block.Bytes))
+						}
+
+					default:
+						return nil, h.Errf("unknown subdirective for client_auth: %s", subdir)
+					}
+				}
+
 			case "alpn":
 				args := h.RemainingArgs()
 				if len(args) == 0 {
diff --git a/caddytest/caddy.ca.cer b/caddytest/caddy.ca.cer
new file mode 100644
index 0000000..00a9a1c
--- /dev/null
+++ b/caddytest/caddy.ca.cer
@@ -0,0 +1,20 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
\ No newline at end of file
diff --git a/caddytest/integration/caddyfile_adapt/tls_client_auth_cert_file.txt b/caddytest/integration/caddyfile_adapt/tls_client_auth_cert_file.txt
new file mode 100644
index 0000000..1e68a4d
--- /dev/null
+++ b/caddytest/integration/caddyfile_adapt/tls_client_auth_cert_file.txt
@@ -0,0 +1,66 @@
+localhost
+
+respond "hello from localhost"
+tls {
+	client_auth {
+		mode request 
+		trusted_ca_cert_file ../caddy.ca.cer
+	}
+}
+----------
+{
+	"apps": {
+		"http": {
+			"servers": {
+				"srv0": {
+					"listen": [
+						":443"
+					],
+					"routes": [
+						{
+							"match": [
+								{
+									"host": [
+										"localhost"
+									]
+								}
+							],
+							"handle": [
+								{
+									"handler": "subroute",
+									"routes": [
+										{
+											"handle": [
+												{
+													"body": "hello from localhost",
+													"handler": "static_response"
+												}
+											]
+										}
+									]
+								}
+							],
+							"terminal": true
+						}
+					],
+					"tls_connection_policies": [
+						{
+							"match": {
+								"sni": [
+									"localhost"
+								]
+							},
+							"client_authentication": {
+								"trusted_ca_certs": [
+									"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"
+								],
+								"mode": "request"
+							}
+						},
+						{}
+					]
+				}
+			}
+		}
+	}
+}
\ No newline at end of file
diff --git a/caddytest/integration/caddyfile_adapt/tls_client_auth_inline_cert.txt b/caddytest/integration/caddyfile_adapt/tls_client_auth_inline_cert.txt
new file mode 100644
index 0000000..028d3b1
--- /dev/null
+++ b/caddytest/integration/caddyfile_adapt/tls_client_auth_inline_cert.txt
@@ -0,0 +1,66 @@
+localhost
+
+respond "hello from localhost"
+tls {
+	client_auth {
+		mode request 
+		trusted_ca_cert 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 
+	}
+}
+----------
+{
+	"apps": {
+		"http": {
+			"servers": {
+				"srv0": {
+					"listen": [
+						":443"
+					],
+					"routes": [
+						{
+							"match": [
+								{
+									"host": [
+										"localhost"
+									]
+								}
+							],
+							"handle": [
+								{
+									"handler": "subroute",
+									"routes": [
+										{
+											"handle": [
+												{
+													"body": "hello from localhost",
+													"handler": "static_response"
+												}
+											]
+										}
+									]
+								}
+							],
+							"terminal": true
+						}
+					],
+					"tls_connection_policies": [
+						{
+							"match": {
+								"sni": [
+									"localhost"
+								]
+							},
+							"client_authentication": {
+								"trusted_ca_certs": [
+									"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"
+								],
+								"mode": "request"
+							}
+						},
+						{}
+					]
+				}
+			}
+		}
+	}
+}
\ No newline at end of file
diff --git a/modules/caddytls/connpolicy.go b/modules/caddytls/connpolicy.go
index 3a18061..fec1fe2 100644
--- a/modules/caddytls/connpolicy.go
+++ b/modules/caddytls/connpolicy.go
@@ -334,7 +334,7 @@ func (clientauth *ClientAuthentication) ConfigureTLSConfig(cfg *tls.Config) erro
 		case "require_and_verify":
 			cfg.ClientAuth = tls.RequireAndVerifyClientCert
 		default:
-			return fmt.Errorf("client auth mode %s not allowed", clientauth.Mode)
+			return fmt.Errorf("client auth mode not recognized: %s", clientauth.Mode)
 		}
 	} else {
 		// otherwise, set a safe default mode
@@ -361,7 +361,6 @@ func (clientauth *ClientAuthentication) ConfigureTLSConfig(cfg *tls.Config) erro
 	// enforce leaf verification by writing our own verify function
 	if len(clientauth.TrustedLeafCerts) > 0 {
 		clientauth.trustedLeafCerts = []*x509.Certificate{}
-
 		for _, clientCertString := range clientauth.TrustedLeafCerts {
 			clientCert, err := decodeBase64DERCert(clientCertString)
 			if err != nil {
@@ -369,10 +368,8 @@ func (clientauth *ClientAuthentication) ConfigureTLSConfig(cfg *tls.Config) erro
 			}
 			clientauth.trustedLeafCerts = append(clientauth.trustedLeafCerts, clientCert)
 		}
-
 		// if a custom verification function already exists, wrap it
 		clientauth.existingVerifyPeerCert = cfg.VerifyPeerCertificate
-
 		cfg.VerifyPeerCertificate = clientauth.verifyPeerCertificate
 	}
 
@@ -411,13 +408,10 @@ func (clientauth ClientAuthentication) verifyPeerCertificate(rawCerts [][]byte,
 
 // decodeBase64DERCert base64-decodes, then DER-decodes, certStr.
 func decodeBase64DERCert(certStr string) (*x509.Certificate, error) {
-	// decode base64
 	derBytes, err := base64.StdEncoding.DecodeString(certStr)
 	if err != nil {
 		return nil, err
 	}
-
-	// parse the DER-encoded certificate
 	return x509.ParseCertificate(derBytes)
 }