tls: expose built-in root certificates

Fixes: #25824
PR-URL: #26415
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Ron Korving <ron@ronkorving.nl>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Sam Roberts <vieuxtech@gmail.com>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>

doc/api/tls.md

@@ -1384,6 +1384,7 @@ changes:
     provided.
     For PEM encoded certificates, supported types are "TRUSTED CERTIFICATE",
     "X509 CERTIFICATE", and "CERTIFICATE".
+    See also [`tls.rootCertificates`].
   * `cert` {string|string[]|Buffer|Buffer[]} Cert chains in PEM format. One cert
     chain should be provided per private key. Each cert chain should consist of
     the PEM formatted certificate for a provided private `key`, followed by the
@@ -1599,6 +1600,17 @@ TLSv1.2 and below.
 console.log(tls.getCiphers()); // ['aes128-gcm-sha256', 'aes128-sha', ...]
 ```
 
+## tls.rootCertificates
+<!-- YAML
+added: REPLACEME
+-->
+
+* {string[]}
+
+An immutable array of strings representing the root certificates (in PEM format)
+used for verifying peer certificates. This is the default value of the `ca`
+option to [`tls.createSecureContext()`].
+
 ## tls.DEFAULT_ECDH_CURVE
 <!-- YAML
 added: v0.11.13
@@ -1784,6 +1796,7 @@ where `secureSocket` has the same API as `pair.cleartext`.
 [`tls.createSecurePair()`]: #tls_tls_createsecurepair_context_isserver_requestcert_rejectunauthorized_options
 [`tls.createServer()`]: #tls_tls_createserver_options_secureconnectionlistener
 [`tls.getCiphers()`]: #tls_tls_getciphers
+[`tls.rootCertificates`]: #tls_tls_rootcertificates
 [Chrome's 'modern cryptography' setting]: https://www.chromium.org/Home/chromium-security/education/tls#TOC-Cipher-Suites
 [DHE]: https://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exchange
 [ECDHE]: https://en.wikipedia.org/wiki/Elliptic_curve_Diffie%E2%80%93Hellman

lib/tls.js

@@ -21,6 +21,8 @@
 
 'use strict';
 
+const { Object } = primordials;
+
 const {
   ERR_TLS_CERT_ALTNAME_INVALID,
   ERR_OUT_OF_RANGE
@@ -33,7 +35,7 @@ const { isArrayBufferView } = require('internal/util/types');
 const net = require('net');
 const { getOptionValue } = require('internal/options');
 const url = require('url');
-const binding = internalBinding('crypto');
+const { getRootCertificates, getSSLCiphers } = internalBinding('crypto');
 const { Buffer } = require('buffer');
 const EventEmitter = require('events');
 const { URL } = require('internal/url');
@@ -76,9 +78,25 @@ else
 
 
 exports.getCiphers = internalUtil.cachedResult(
-  () => internalUtil.filterDuplicateStrings(binding.getSSLCiphers(), true)
+  () => internalUtil.filterDuplicateStrings(getSSLCiphers(), true)
 );
 
+let rootCertificates;
+
+function cacheRootCertificates() {
+  rootCertificates = Object.freeze(getRootCertificates());
+}
+
+Object.defineProperty(exports, 'rootCertificates', {
+  configurable: false,
+  enumerable: true,
+  get: () => {
+    // Out-of-line caching to promote inlining the getter.
+    if (!rootCertificates) cacheRootCertificates();
+    return rootCertificates;
+  },
+});
+
 // Convert protocols array into valid OpenSSL protocols list
 // ("\x06spdy/2\x08http/1.1\x08http/1.0")
 function convertProtocols(protocols) {

src/node_crypto.cc

@@ -944,6 +944,24 @@ static X509_STORE* NewRootCertStore() {
 }
 
 
+void GetRootCertificates(const FunctionCallbackInfo<Value>& args) {
+  Environment* env = Environment::GetCurrent(args);
+  Local<Array> result = Array::New(env->isolate(), arraysize(root_certs));
+
+  for (size_t i = 0; i < arraysize(root_certs); i++) {
+    Local<Value> value;
+    if (!String::NewFromOneByte(env->isolate(),
+                                reinterpret_cast<const uint8_t*>(root_certs[i]),
+                                NewStringType::kNormal).ToLocal(&value) ||
+        !result->Set(env->context(), i, value).FromMaybe(false)) {
+      return;
+    }
+  }
+
+  args.GetReturnValue().Set(result);
+}
+
+
 void SecureContext::AddCACert(const FunctionCallbackInfo<Value>& args) {
   Environment* env = Environment::GetCurrent(args);
 
@@ -6870,6 +6888,8 @@ void Initialize(Local<Object> target,
   env->SetMethodNoSideEffect(target, "certVerifySpkac", VerifySpkac);
   env->SetMethodNoSideEffect(target, "certExportPublicKey", ExportPublicKey);
   env->SetMethodNoSideEffect(target, "certExportChallenge", ExportChallenge);
+  env->SetMethodNoSideEffect(target, "getRootCertificates",
+                             GetRootCertificates);
   // Exposed for testing purposes only.
   env->SetMethodNoSideEffect(target, "isExtraRootCertsFileLoaded",
                              IsExtraRootCertsFileLoaded);