Throw exception when channel binding is not supported

Instead of returning null.

Author: Sjord

Zend/Optimizer/zend_func_infos.h

@@ -297,7 +297,7 @@ static const func_info_t func_infos[] = {
 	F1("openssl_get_curve_names", MAY_BE_ARRAY|MAY_BE_ARRAY_KEY_LONG|MAY_BE_ARRAY_OF_STRING|MAY_BE_FALSE),
 #endif
 	F1("openssl_get_cert_locations", MAY_BE_ARRAY|MAY_BE_ARRAY_KEY_STRING|MAY_BE_ARRAY_OF_STRING),
-	F1("openssl_get_channel_binding", MAY_BE_STRING|MAY_BE_NULL),
+	F1("openssl_get_channel_binding", MAY_BE_STRING),
 	FN("pcntl_signal_get_handler", MAY_BE_STRING|MAY_BE_ARRAY|MAY_BE_ARRAY_KEY_LONG|MAY_BE_ARRAY_OF_STRING|MAY_BE_ARRAY_OF_OBJECT|MAY_BE_OBJECT|MAY_BE_LONG),
 	FN("preg_replace", MAY_BE_STRING|MAY_BE_ARRAY|MAY_BE_ARRAY_KEY_LONG|MAY_BE_ARRAY_KEY_STRING|MAY_BE_ARRAY_OF_STRING|MAY_BE_NULL),
 	FN("preg_filter", MAY_BE_STRING|MAY_BE_ARRAY|MAY_BE_ARRAY_KEY_LONG|MAY_BE_ARRAY_KEY_STRING|MAY_BE_ARRAY_OF_STRING|MAY_BE_NULL),

ext/openssl/openssl.c

@@ -57,6 +57,10 @@ ZEND_DECLARE_MODULE_GLOBALS(openssl)
 
 zend_class_entry *php_openssl_exception_ce;
 
+/* Openssl\UnsupportedChannelBindingException class */
+
+static zend_class_entry *php_openssl_unsupported_channel_binding_exception_ce;
+
 /* Openssl\ChannelBindingType enum */
 
 static zend_class_entry *php_openssl_channel_binding_type_ce;
@@ -761,6 +765,8 @@ PHP_INI_END()
 PHP_MINIT_FUNCTION(openssl)
 {
 	php_openssl_exception_ce = register_class_Openssl_OpensslException(zend_ce_exception);
+	php_openssl_unsupported_channel_binding_exception_ce =
+		register_class_Openssl_UnsupportedChannelBindingException(php_openssl_exception_ce);
 	php_openssl_channel_binding_type_ce = register_class_Openssl_ChannelBindingType();
 
 	php_openssl_certificate_ce = register_class_OpenSSLCertificate();
@@ -5127,10 +5133,24 @@ PHP_FUNCTION(openssl_get_channel_binding)
 		case PHP_OPENSSL_CHANNEL_BINDING_RESULT_OK:
 			RETURN_STR(result);
 		case PHP_OPENSSL_CHANNEL_BINDING_RESULT_NOT_APPLICABLE:
-			RETURN_NULL();
+			switch (type) {
+				case ZEND_ENUM_Openssl_ChannelBindingType_TlsUnique:
+					zend_throw_exception(php_openssl_unsupported_channel_binding_exception_ce,
+						"Channel binding type \"tls-unique\" is not supported for TLS 1.3", 0);
+					break;
+				case ZEND_ENUM_Openssl_ChannelBindingType_TlsServerEndPoint:
+					zend_throw_exception(php_openssl_unsupported_channel_binding_exception_ce,
+						"Channel binding type \"tls-server-end-point\" requires a certificate", 0);
+					break;
+				default:
+					zend_throw_exception(php_openssl_unsupported_channel_binding_exception_ce,
+						"Channel binding type is not applicable to this connection", 0);
+					break;
+			}
+			RETURN_THROWS();
 		case PHP_OPENSSL_CHANNEL_BINDING_RESULT_NOT_TLS:
-			zend_throw_exception_ex(php_openssl_exception_ce, 0,
-				"Stream does not have transport encryption enabled");
+			zend_throw_exception(zend_ce_value_error,
+				"Stream does not have transport encryption enabled", 0);
 			RETURN_THROWS();
 		case PHP_OPENSSL_CHANNEL_BINDING_RESULT_ERROR:
 			{

ext/openssl/openssl.stub.php

@@ -11,6 +11,10 @@ class OpensslException extends Exception
     {
     }
 
+    class UnsupportedChannelBindingException extends OpensslException
+    {
+    }
+
     /**
      * Channel binding type for openssl_get_channel_binding().
      * The backing values are the IANA "Channel Binding" registry names.
@@ -793,6 +797,6 @@ function openssl_password_verify(string $algo, #[\SensitiveParameter] string $pa
   * @param resource $stream
   * @refcount 1
   */
-function openssl_get_channel_binding($stream, Openssl\ChannelBindingType $channel_binding_type): ?string {}
+function openssl_get_channel_binding($stream, Openssl\ChannelBindingType $channel_binding_type): string {}
 
 }

ext/openssl/openssl_arginfo.h

@@ -229,7 +229,7 @@ typedef struct _php_openssl_session_object {
 /* Result of php_openssl_netstream_get_channel_binding(). */
 typedef enum php_openssl_channel_binding_result {
 	PHP_OPENSSL_CHANNEL_BINDING_RESULT_OK = 0,		/* *out holds a zend_string with the data */
-	PHP_OPENSSL_CHANNEL_BINDING_RESULT_NOT_APPLICABLE,	/* *out = NULL (e.g. tls-unique over TLS 1.3) */
+	PHP_OPENSSL_CHANNEL_BINDING_RESULT_NOT_APPLICABLE,	/* *out = NULL (e.g. tls-unique over TLS 1.3, or tls-server-end-point without a certificate) */
 	PHP_OPENSSL_CHANNEL_BINDING_RESULT_NOT_TLS,	/* stream is not an active TLS stream */
 	PHP_OPENSSL_CHANNEL_BINDING_RESULT_ERROR,		/* an OpenSSL-level failure occurred */
 } php_openssl_channel_binding_result;

ext/openssl/openssl_decl.h

@@ -33,7 +33,13 @@ try {
     echo $e::class, ': ', $e->getMessage(), "\n";
 }
 
-/* A stream without transport encryption -> Openssl\OpensslException. */
+/* The unsupported-type exception extends the general OpenSSL exception. */
+var_dump(is_subclass_of(
+    Openssl\UnsupportedChannelBindingException::class,
+    Openssl\OpensslException::class,
+));
+
+/* A stream without transport encryption -> ValueError. */
 $plain = fopen("php://memory", "r");
 foreach (Openssl\ChannelBindingType::cases() as $type) {
     try {
@@ -52,6 +58,7 @@ TlsExporter=tls-exporter
 TypeError: openssl_get_channel_binding(): Argument #2 ($channel_binding_type) must be of type Openssl\ChannelBindingType, string given
 TypeError: openssl_get_channel_binding(): Argument #2 ($channel_binding_type) must be of type Openssl\ChannelBindingType, string given
 TypeError: openssl_get_channel_binding(): Argument #1 ($stream) must be of type resource, int given
-tls-unique: Openssl\OpensslException: Stream does not have transport encryption enabled
-tls-server-end-point: Openssl\OpensslException: Stream does not have transport encryption enabled
-tls-exporter: Openssl\OpensslException: Stream does not have transport encryption enabled
+bool(true)
+tls-unique: ValueError: Stream does not have transport encryption enabled
+tls-server-end-point: ValueError: Stream does not have transport encryption enabled
+tls-exporter: ValueError: Stream does not have transport encryption enabled

ext/openssl/php_openssl.h

@@ -0,0 +1,71 @@
+--TEST--
+openssl_get_channel_binding(): TLS 1.2 PSK, tls-server-end-point is not applicable
+--EXTENSIONS--
+openssl
+--SKIPIF--
+<?php
+if (!function_exists("proc_open")) die("skip no proc_open");
+if (OPENSSL_VERSION_NUMBER < 0x10101000) die("skip OpenSSL >= 1.1.1 required");
+?>
+--FILE--
+<?php
+$serverCode = <<<'CODE'
+    $serverCtx = stream_context_create(['ssl' => [
+        'crypto_method' => STREAM_CRYPTO_METHOD_TLSv1_2_SERVER,
+        'ciphers' => 'PSK',
+        'psk_server_cb' => function ($stream, string $identity): ?Openssl\Psk {
+            if ($identity === 'client_id') {
+                return new Openssl\Psk("\x00\x11\x22\x33\x44\x55\x66\x77\x88\x99\xaa\xbb\xcc\xdd\xee\xff");
+            }
+            return null;
+        },
+    ]]);
+    $server = stream_socket_server('tls://127.0.0.1:0', $errno, $errstr,
+        STREAM_SERVER_BIND | STREAM_SERVER_LISTEN, $serverCtx);
+    phpt_notify_server_start($server);
+    $conn = stream_socket_accept($server, 30);
+    fwrite($conn, "ready");
+    phpt_wait();
+    fclose($conn);
+CODE;
+
+$clientCode = <<<'CODE'
+    $clientCtx = stream_context_create(['ssl' => [
+        'crypto_method' => STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT,
+        'ciphers' => 'PSK',
+        'verify_peer' => false,
+        'verify_peer_name' => false,
+        'psk_client_cb' => function ($stream): ?Openssl\Psk {
+            return new Openssl\Psk(
+                "\x00\x11\x22\x33\x44\x55\x66\x77\x88\x99\xaa\xbb\xcc\xdd\xee\xff",
+                'client_id'
+            );
+        },
+    ]]);
+    $client = stream_socket_client('tls://{{ ADDR }}', $errno, $errstr,
+        30, STREAM_CLIENT_CONNECT, $clientCtx);
+    var_dump($client !== false);
+    var_dump(fread($client, 1024));
+
+    foreach (Openssl\ChannelBindingType::cases() as $type) {
+        try {
+            $v = openssl_get_channel_binding($client, $type);
+            printf("%s len=%d\n", $type->value, strlen($v));
+        } catch (Openssl\UnsupportedChannelBindingException $e) {
+            echo $e::class, ': ', $e->getMessage(), "\n";
+        }
+    }
+
+    phpt_notify('server');
+    fclose($client);
+CODE;
+
+include __DIR__ . '/ServerClientTestCase.inc';
+ServerClientTestCase::getInstance()->run($clientCode, $serverCode);
+?>
+--EXPECTF--
+bool(true)
+string(5) "ready"
+tls-unique len=%d
+Openssl\UnsupportedChannelBindingException: Channel binding type "tls-server-end-point" requires a certificate
+tls-exporter len=32

ext/openssl/tests/openssl_get_channel_binding_errors.phpt

@@ -28,8 +28,12 @@ $serverCode = <<<'CODE'
         exit(1);
     }
     foreach (Openssl\ChannelBindingType::cases() as $type) {
-        $v = openssl_get_channel_binding($conn, $type);
-        fwrite($conn, $type->value . "=" . (is_string($v) ? bin2hex($v) : "") . "\n");
+        try {
+            $v = openssl_get_channel_binding($conn, $type);
+            fwrite($conn, $type->value . "=" . bin2hex($v) . "\n");
+        } catch (Openssl\UnsupportedChannelBindingException) {
+            fwrite($conn, $type->value . "=unsupported\n");
+        }
     }
     phpt_wait();
     fclose($conn);
@@ -50,8 +54,14 @@ $clientCode = <<<'CODE'
     }
 
     $my = [];
+    $myException = [];
     foreach (Openssl\ChannelBindingType::cases() as $type) {
-        $my[$type->value] = openssl_get_channel_binding($client, $type);
+        try {
+            $my[$type->value] = openssl_get_channel_binding($client, $type);
+        } catch (Openssl\UnsupportedChannelBindingException $e) {
+            $my[$type->value] = null;
+            $myException[$type->value] = $e::class . ': ' . $e->getMessage();
+        }
     }
 
     $peer = [];
@@ -62,7 +72,7 @@ $clientCode = <<<'CODE'
         $eq = strpos($line, "=");
         $t = substr($line, 0, $eq);
         $enc = substr($line, $eq + 1);
-        $peer[$t] = ($enc === "") ? null : hex2bin($enc);
+        $peer[$t] = ($enc === "unsupported") ? null : hex2bin($enc);
     }
 
     foreach (Openssl\ChannelBindingType::cases() as $type) {
@@ -75,7 +85,8 @@ $clientCode = <<<'CODE'
             $t, var_export($c === $s, true), $lc, $ls);
     }
 
-    echo "tls_unique_is_null=" . var_export($my["tls-unique"] === null, true) . "\n";
+    echo "tls_unique_unsupported=" . var_export($my["tls-unique"] === null, true) . "\n";
+    echo "tls_unique_message=" . ($myException["tls-unique"] ?? "none") . "\n";
 
     $opts = stream_context_get_options($client);
     $cert = $opts['ssl']['peer_certificate'] ?? null;
@@ -102,5 +113,6 @@ ServerClientTestCase::getInstance()->run($clientCode, ['server' => $serverCode])
 tls-unique equal=true len_client=null len_server=null
 tls-server-end-point equal=true len_client=32 len_server=32
 tls-exporter equal=true len_client=32 len_server=32
-tls_unique_is_null=true
+tls_unique_unsupported=true
+tls_unique_message=Openssl\UnsupportedChannelBindingException: Channel binding type "tls-unique" is not supported for TLS 1.3
 tse_matches_sha256_fingerprint=true

ext/openssl/tests/openssl_get_channel_binding_psk.phpt

@@ -3970,8 +3970,8 @@ static int php_openssl_get_cert_signature_md_nid(const X509 *cert) /* {{{ */
  *
  * On success *out is set to a newly-allocated zend_string holding the data
  * and PHP_OPENSSL_CHANNEL_BINDING_RESULT_OK is returned. For a type that is not applicable to the
- * connection (currently: tls-unique over TLS 1.3) *out is set to NULL and
- * PHP_OPENSSL_CHANNEL_BINDING_RESULT_NOT_APPLICABLE is returned. If the stream is not an active TLS
+ * connection (tls-unique over TLS 1.3, or tls-server-end-point without a certificate) *out is set
+ * to NULL and PHP_OPENSSL_CHANNEL_BINDING_RESULT_NOT_APPLICABLE is returned. If the stream is not an active TLS
  * stream PHP_OPENSSL_CHANNEL_BINDING_RESULT_NOT_TLS is returned, and if an OpenSSL call fails
  * PHP_OPENSSL_CHANNEL_BINDING_RESULT_ERROR is returned; in both of these cases *out is set to NULL.
  */
@@ -4029,7 +4029,7 @@ php_openssl_channel_binding_result php_openssl_netstream_get_channel_binding( /*
 			unsigned int digest_len = 0;
 
 			if (cert == NULL) {
-				return PHP_OPENSSL_CHANNEL_BINDING_RESULT_ERROR;
+				return PHP_OPENSSL_CHANNEL_BINDING_RESULT_NOT_APPLICABLE;
 			}
 
 			md_nid = php_openssl_get_cert_signature_md_nid(cert);