security_context_linux.cc

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// Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
 
#if !defined(DART_IO_SECURE_SOCKET_DISABLED)
 
#include "platform/globals.h"
#if defined(DART_HOST_OS_LINUX) || defined(DART_HOST_OS_ANDROID)
 
#include "bin/security_context.h"
 
#include <openssl/bio.h>
#include <openssl/ssl.h>
#include <openssl/x509.h>
 
#include "bin/directory.h"
#include "bin/file.h"
#include "bin/secure_socket_filter.h"
#include "bin/secure_socket_utils.h"
#include "platform/syslog.h"
 
namespace dart {
namespace bin {
 
// The security context won't necessarily use the compiled-in root certificates,
// but since there is no way to update the size of the allocation after creating
// the weak persistent handle, we assume that it will. Note that when the
// root certs aren't compiled in, |root_certificates_pem_length| is 0.
const intptr_t SSLCertContext::kApproximateSize =
    sizeof(SSLCertContext) + root_certificates_pem_length;
 
void SSLCertContext::TrustBuiltinRoots() {
  // First, try to use locations specified on the command line.
  if (root_certs_file() != nullptr) {
    LoadRootCertFile(root_certs_file());
    return;
  }
  if (root_certs_cache() != nullptr) {
    LoadRootCertCache(root_certs_cache());
    return;
  }
 
  if (bypass_trusting_system_roots()) {
    if (SSL_LOG_STATUS) {
      Syslog::Print("Bypass trusting built-in system roots\n");
    }
  } else {
#if defined(DART_HOST_OS_ANDROID)
    // On Android, we don't compile in the trusted root certificates. Instead,
    // we use the directory of trusted certificates already present on the
    // device. This saves ~240KB from the size of the binary. This has the
    // drawback that SSL_do_handshake will synchronously hit the filesystem
    // looking for root certs during its trust evaluation. We call
    // SSL_do_handshake directly from the Dart thread so that Dart code can be
    // invoked from the "bad certificate" callback called by SSL_do_handshake.
    const char* android_cacerts = "/system/etc/security/cacerts";
    LoadRootCertCache(android_cacerts);
    return;
#else
    // On Linux, we use the compiled-in trusted certs as a last resort. First,
    // we try to find the trusted certs in various standard locations. A good
    // discussion of the complexities of this endeavor can be found here:
    //
    // https://www.happyassassin.net/2015/01/12/a-note-about-ssltls-trusted-certificate-stores-and-platforms/
    const char* bundle = "/etc/pki/tls/certs/ca-bundle.crt";
    const char* cachedir = "/etc/ssl/certs";
    if (File::Exists(nullptr, bundle)) {
      LoadRootCertFile(bundle);
      return;
    }
 
    if (Directory::Exists(nullptr, cachedir) == Directory::EXISTS) {
      LoadRootCertCache(cachedir);
      return;
    }
#endif
  }
 
#if defined(DART_HOST_OS_LINUX)
  // Fall back on the compiled-in certs if the standard locations don't exist.
  if (SSL_LOG_STATUS) {
    Syslog::Print("Trusting compiled-in roots\n");
  }
  AddCompiledInCerts();
#endif
}
 
void SSLCertContext::RegisterCallbacks(SSL* ssl) {
  // No callbacks to register for implementations using BoringSSL's built-in
  // verification mechanism.
}
 
TrustEvaluateHandlerFunc SSLCertContext::GetTrustEvaluateHandler() const {
  return nullptr;
}
 
}  // namespace bin
}  // namespace dart
 
#endif  // defined(DART_HOST_OS_LINUX) || defined(DART_HOST_OS_ANDROID)
 
#endif  // !defined(DART_IO_SECURE_SOCKET_DISABLED)