crypto: added support for reading certificates from macOS system store

PR-URL: #56599
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Joyee Cheung <[email protected]>

Author: timja

doc/api/cli.md

@@ -2833,6 +2833,13 @@ The following values are valid for `mode`:
 * `silent`: If supported by the OS, mapping will be attempted. Failure to map
   will be ignored and will not be reported.
 
+### `--use-system-ca`
+
+Node.js uses the trusted CA certificates present in the system store along with
+the `--use-bundled-ca`, `--use-openssl-ca` options.
+
+This option is available to macOS only.
+
 ### `--v8-options`
 
 <!-- YAML
@@ -3233,6 +3240,7 @@ one is included in the list below.
 * `--use-bundled-ca`
 * `--use-largepages`
 * `--use-openssl-ca`
+* `--use-system-ca`
 * `--v8-pool-size`
 * `--watch-path`
 * `--watch-preserve-output`

doc/api/tls.md

@@ -2400,6 +2400,9 @@ from the bundled Mozilla CA store as supplied by the current Node.js version.
 The bundled CA store, as supplied by Node.js, is a snapshot of Mozilla CA store
 that is fixed at release time. It is identical on all supported platforms.
 
+On macOS if `--use-system-ca` is passed then trusted certificates
+from the user and system keychains are also included.
+
 ## `tls.DEFAULT_ECDH_CURVE`
 
 <!-- YAML

node.gypi

@@ -238,8 +238,9 @@
 
     [ 'OS=="mac"', {
       # linking Corefoundation is needed since certain macOS debugging tools
-      # like Instruments require it for some features
-      'libraries': [ '-framework CoreFoundation' ],
+      # like Instruments require it for some features. Security is needed for
+      # --use-system-ca.
+      'libraries': [ '-framework CoreFoundation -framework Security' ],
       'defines!': [
         'NODE_PLATFORM="mac"',
       ],

src/crypto/crypto_context.cc

@@ -18,6 +18,9 @@
 #ifndef OPENSSL_NO_ENGINE
 #include <openssl/engine.h>
 #endif  // !OPENSSL_NO_ENGINE
+#ifdef __APPLE__
+#include <Security/Security.h>
+#endif
 
 namespace node {
 
@@ -232,6 +235,306 @@ unsigned long LoadCertsFromFile(  // NOLINT(runtime/int)
   }
 }
 
+// Indicates the trust status of a certificate.
+enum class TrustStatus {
+  // Trust status is unknown / uninitialized.
+  UNKNOWN,
+  // Certificate inherits trust value from its issuer. If the certificate is the
+  // root of the chain, this implies distrust.
+  UNSPECIFIED,
+  // Certificate is a trust anchor.
+  TRUSTED,
+  // Certificate is blocked / explicitly distrusted.
+  DISTRUSTED
+};
+
+bool isSelfIssued(X509* cert) {
+  auto subject = X509_get_subject_name(cert);
+  auto issuer = X509_get_issuer_name(cert);
+
+  return X509_NAME_cmp(subject, issuer) == 0;
+}
+
+#ifdef __APPLE__
+// This code is loosely based on
+// https://github.com/chromium/chromium/blob/54bd8e3/net/cert/internal/trust_store_mac.cc
+// Copyright 2015 The Chromium Authors
+// Licensed under a BSD-style license
+// See https://chromium.googlesource.com/chromium/src/+/HEAD/LICENSE for
+// details.
+TrustStatus IsTrustDictionaryTrustedForPolicy(CFDictionaryRef trust_dict,
+                                              bool is_self_issued) {
+  // Trust settings may be scoped to a single application
+  // skip as this is not supported
+  if (CFDictionaryContainsKey(trust_dict, kSecTrustSettingsApplication)) {
+    return TrustStatus::UNSPECIFIED;
+  }
+
+  // Trust settings may be scoped using policy-specific constraints. For
+  // example, SSL trust settings might be scoped to a single hostname, or EAP
+  // settings specific to a particular WiFi network.
+  // As this is not presently supported, skip any policy-specific trust
+  // settings.
+  if (CFDictionaryContainsKey(trust_dict, kSecTrustSettingsPolicyString)) {
+    return TrustStatus::UNSPECIFIED;
+  }
+
+  // If the trust settings are scoped to a specific policy (via
+  // kSecTrustSettingsPolicy), ensure that the policy is the same policy as
+  // |kSecPolicyAppleSSL|. If there is no kSecTrustSettingsPolicy key, it's
+  // considered a match for all policies.
+  if (CFDictionaryContainsKey(trust_dict, kSecTrustSettingsPolicy)) {
+    SecPolicyRef policy_ref = reinterpret_cast<SecPolicyRef>(const_cast<void*>(
+        CFDictionaryGetValue(trust_dict, kSecTrustSettingsPolicy)));
+
+    if (!policy_ref) {
+      return TrustStatus::UNSPECIFIED;
+    }
+
+    CFDictionaryRef policy_dict(SecPolicyCopyProperties(policy_ref));
+
+    // kSecPolicyOid is guaranteed to be present in the policy dictionary.
+    CFStringRef policy_oid = reinterpret_cast<CFStringRef>(
+        const_cast<void*>(CFDictionaryGetValue(policy_dict, kSecPolicyOid)));
+
+    if (!CFEqual(policy_oid, kSecPolicyAppleSSL)) {
+      return TrustStatus::UNSPECIFIED;
+    }
+  }
+
+  int trust_settings_result = kSecTrustSettingsResultTrustRoot;
+  if (CFDictionaryContainsKey(trust_dict, kSecTrustSettingsResult)) {
+    CFNumberRef trust_settings_result_ref =
+        reinterpret_cast<CFNumberRef>(const_cast<void*>(
+            CFDictionaryGetValue(trust_dict, kSecTrustSettingsResult)));
+
+    if (!trust_settings_result_ref ||
+        !CFNumberGetValue(trust_settings_result_ref,
+                          kCFNumberIntType,
+                          &trust_settings_result)) {
+      return TrustStatus::UNSPECIFIED;
+    }
+
+    if (trust_settings_result == kSecTrustSettingsResultDeny) {
+      return TrustStatus::DISTRUSTED;
+    }
+
+    // This is a bit of a hack: if the cert is self-issued allow either
+    // kSecTrustSettingsResultTrustRoot or kSecTrustSettingsResultTrustAsRoot on
+    // the basis that SecTrustSetTrustSettings should not allow creating an
+    // invalid trust record in the first place. (The spec is that
+    // kSecTrustSettingsResultTrustRoot can only be applied to root(self-signed)
+    // certs and kSecTrustSettingsResultTrustAsRoot is used for other certs.)
+    // This hack avoids having to check the signature on the cert which is slow
+    // if using the platform APIs, and may require supporting MD5 signature
+    // algorithms on some older OSX versions or locally added roots, which is
+    // undesirable in the built-in signature verifier.
+    if (is_self_issued) {
+      return trust_settings_result == kSecTrustSettingsResultTrustRoot ||
+                     trust_settings_result == kSecTrustSettingsResultTrustAsRoot
+                 ? TrustStatus::TRUSTED
+                 : TrustStatus::UNSPECIFIED;
+    }
+
+    // kSecTrustSettingsResultTrustAsRoot can only be applied to non-root certs.
+    return (trust_settings_result == kSecTrustSettingsResultTrustAsRoot)
+               ? TrustStatus::TRUSTED
+               : TrustStatus::UNSPECIFIED;
+  }
+
+  return TrustStatus::UNSPECIFIED;
+}
+
+TrustStatus IsTrustSettingsTrustedForPolicy(CFArrayRef trust_settings,
+                                            bool is_self_issued) {
+  // The trust_settings parameter can return a valid but empty CFArrayRef.
+  // This empty trust-settings array means “always trust this certificate”
+  // with an overall trust setting for the certificate of
+  // kSecTrustSettingsResultTrustRoot
+  if (CFArrayGetCount(trust_settings) == 0) {
+    return is_self_issued ? TrustStatus::TRUSTED : TrustStatus::UNSPECIFIED;
+  }
+
+  for (CFIndex i = 0; i < CFArrayGetCount(trust_settings); ++i) {
+    CFDictionaryRef trust_dict = reinterpret_cast<CFDictionaryRef>(
+        const_cast<void*>(CFArrayGetValueAtIndex(trust_settings, i)));
+
+    TrustStatus trust =
+        IsTrustDictionaryTrustedForPolicy(trust_dict, is_self_issued);
+
+    if (trust == TrustStatus::DISTRUSTED || trust == TrustStatus::TRUSTED) {
+      return trust;
+    }
+  }
+  return TrustStatus::UNSPECIFIED;
+}
+
+bool IsCertificateTrustValid(SecCertificateRef ref) {
+  SecTrustRef sec_trust = nullptr;
+  CFMutableArrayRef subj_certs =
+      CFArrayCreateMutable(nullptr, 1, &kCFTypeArrayCallBacks);
+  CFArraySetValueAtIndex(subj_certs, 0, ref);
+
+  SecPolicyRef policy = SecPolicyCreateSSL(false, nullptr);
+  OSStatus ortn =
+      SecTrustCreateWithCertificates(subj_certs, policy, &sec_trust);
+  bool result = false;
+  if (ortn) {
+    /* should never happen */
+  } else {
+    result = SecTrustEvaluateWithError(sec_trust, nullptr);
+  }
+
+  if (policy) {
+    CFRelease(policy);
+  }
+  if (sec_trust) {
+    CFRelease(sec_trust);
+  }
+  if (subj_certs) {
+    CFRelease(subj_certs);
+  }
+  return result;
+}
+
+bool IsCertificateTrustedForPolicy(X509* cert, SecCertificateRef ref) {
+  OSStatus err;
+
+  bool trust_evaluated = false;
+  bool is_self_issued = isSelfIssued(cert);
+
+  // Evaluate user trust domain, then admin. User settings can override
+  // admin (and both override the system domain, but we don't check that).
+  for (const auto& trust_domain :
+       {kSecTrustSettingsDomainUser, kSecTrustSettingsDomainAdmin}) {
+    CFArrayRef trust_settings = nullptr;
+    err = SecTrustSettingsCopyTrustSettings(ref, trust_domain, &trust_settings);
+
+    if (err != errSecSuccess && err != errSecItemNotFound) {
+      fprintf(stderr,
+              "ERROR: failed to copy trust settings of system certificate%d\n",
+              err);
+      continue;
+    }
+
+    if (err == errSecSuccess && trust_settings != nullptr) {
+      TrustStatus result =
+          IsTrustSettingsTrustedForPolicy(trust_settings, is_self_issued);
+      if (result != TrustStatus::UNSPECIFIED) {
+        CFRelease(trust_settings);
+        return result == TrustStatus::TRUSTED;
+      }
+    }
+
+    // An empty trust settings array isn’t the same as no trust settings,
+    // where the trust_settings parameter returns NULL.
+    // No trust-settings array means
+    // “this certificate must be verifiable using a known trusted certificate”.
+    if (trust_settings == nullptr && !trust_evaluated) {
+      bool result = IsCertificateTrustValid(ref);
+      if (result) {
+        return true;
+      }
+      // no point re-evaluating this in the admin domain
+      trust_evaluated = true;
+    } else if (trust_settings) {
+      CFRelease(trust_settings);
+    }
+  }
+  return false;
+}
+
+void ReadMacOSKeychainCertificates(
+    std::vector<std::string>* system_root_certificates) {
+  CFTypeRef search_keys[] = {kSecClass, kSecMatchLimit, kSecReturnRef};
+  CFTypeRef search_values[] = {
+      kSecClassCertificate, kSecMatchLimitAll, kCFBooleanTrue};
+  CFDictionaryRef search = CFDictionaryCreate(kCFAllocatorDefault,
+                                              search_keys,
+                                              search_values,
+                                              3,
+                                              &kCFTypeDictionaryKeyCallBacks,
+                                              &kCFTypeDictionaryValueCallBacks);
+
+  CFArrayRef curr_anchors = nullptr;
+  OSStatus ortn =
+      SecItemCopyMatching(search, reinterpret_cast<CFTypeRef*>(&curr_anchors));
+  CFRelease(search);
+
+  if (ortn) {
+    fprintf(stderr, "ERROR: SecItemCopyMatching failed %d\n", ortn);
+  }
+
+  CFIndex count = CFArrayGetCount(curr_anchors);
+
+  std::vector<X509*> system_root_certificates_X509;
+  for (int i = 0; i < count; ++i) {
+    SecCertificateRef cert_ref = reinterpret_cast<SecCertificateRef>(
+        const_cast<void*>(CFArrayGetValueAtIndex(curr_anchors, i)));
+
+    CFDataRef der_data = SecCertificateCopyData(cert_ref);
+    if (!der_data) {
+      fprintf(stderr, "ERROR: SecCertificateCopyData failed\n");
+      continue;
+    }
+    auto data_buffer_pointer = CFDataGetBytePtr(der_data);
+
+    X509* cert =
+        d2i_X509(nullptr, &data_buffer_pointer, CFDataGetLength(der_data));
+    CFRelease(der_data);
+    bool is_valid = IsCertificateTrustedForPolicy(cert, cert_ref);
+    if (is_valid) {
+      system_root_certificates_X509.emplace_back(cert);
+    }
+  }
+  CFRelease(curr_anchors);
+
+  for (size_t i = 0; i < system_root_certificates_X509.size(); i++) {
+    ncrypto::X509View x509_view(system_root_certificates_X509[i]);
+
+    auto pem_bio = x509_view.toPEM();
+    if (!pem_bio) {
+      fprintf(stderr,
+              "Warning: converting system certificate to PEM format failed\n");
+      continue;
+    }
+
+    char* pem_data = nullptr;
+    auto pem_size = BIO_get_mem_data(pem_bio.get(), &pem_data);
+    if (pem_size <= 0 || !pem_data) {
+      fprintf(
+          stderr,
+          "Warning: cannot read PEM-encoded data from system certificate\n");
+      continue;
+    }
+    std::string certificate_string_pem(pem_data, pem_size);
+
+    system_root_certificates->emplace_back(certificate_string_pem);
+  }
+}
+#endif  // __APPLE__
+
+void ReadSystemStoreCertificates(
+    std::vector<std::string>* system_root_certificates) {
+#ifdef __APPLE__
+  ReadMacOSKeychainCertificates(system_root_certificates);
+#endif
+}
+
+std::vector<std::string> getCombinedRootCertificates() {
+  std::vector<std::string> combined_root_certs;
+
+  for (size_t i = 0; i < arraysize(root_certs); i++) {
+    combined_root_certs.emplace_back(root_certs[i]);
+  }
+
+  if (per_process::cli_options->use_system_ca) {
+    ReadSystemStoreCertificates(&combined_root_certs);
+  }
+
+  return combined_root_certs;
+}
+
 X509_STORE* NewRootCertStore() {
   static std::vector<X509*> root_certs_vector;
   static bool root_certs_vector_loaded = false;
@@ -240,12 +543,17 @@ X509_STORE* NewRootCertStore() {
 
   if (!root_certs_vector_loaded) {
     if (per_process::cli_options->ssl_openssl_cert_store == false) {
-      for (size_t i = 0; i < arraysize(root_certs); i++) {
-        X509* x509 = PEM_read_bio_X509(
-            NodeBIO::NewFixed(root_certs[i], strlen(root_certs[i])).get(),
-            nullptr,  // no re-use of X509 structure
-            NoPasswordCallback,
-            nullptr);  // no callback data
+      std::vector<std::string> combined_root_certs =
+          getCombinedRootCertificates();
+
+      for (size_t i = 0; i < combined_root_certs.size(); i++) {
+        X509* x509 =
+            PEM_read_bio_X509(NodeBIO::NewFixed(combined_root_certs[i].data(),
+                                                combined_root_certs[i].length())
+                                  .get(),
+                              nullptr,  // no re-use of X509 structure
+                              NoPasswordCallback,
+                              nullptr);  // no callback data
 
         // Parse errors from the built-in roots are fatal.
         CHECK_NOT_NULL(x509);

src/node_options.cc

@@ -1120,6 +1120,10 @@ PerProcessOptionsParser::PerProcessOptionsParser(
             ,
             &PerProcessOptions::use_openssl_ca,
             kAllowedInEnvvar);
+  AddOption("--use-system-ca",
+            "use system's CA store",
+            &PerProcessOptions::use_system_ca,
+            kAllowedInEnvvar);
   AddOption("--use-bundled-ca",
             "use bundled CA store"
 #if !defined(NODE_OPENSSL_CERT_STORE)