// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "net/cert/cert_database.h"

#include <cert.h>
#include <pk11pub.h>
#include <secmod.h>

#include "base/logging.h"
#include "base/observer_list_threadsafe.h"
#include "crypto/nss_util.h"
#include "crypto/scoped_nss_types.h"
#include "net/base/net_errors.h"
#include "net/cert/nss_cert_database.h"
#include "net/cert/x509_certificate.h"
#include "net/cert/x509_util_nss.h"

namespace net {

// Helper that observes events from the NSSCertDatabase and forwards them to
// the given CertDatabase.
class CertDatabase::Notifier : public NSSCertDatabase::Observer {
 public:
  explicit Notifier(CertDatabase* cert_db) : cert_db_(cert_db) {
    NSSCertDatabase::GetInstance()->AddObserver(this);
  }

  virtual ~Notifier() {
    NSSCertDatabase::GetInstance()->RemoveObserver(this);
  }

  // NSSCertDatabase::Observer implementation:
  virtual void OnCertAdded(const X509Certificate* cert) OVERRIDE {
    cert_db_->NotifyObserversOfCertAdded(cert);
  }

  virtual void OnCertRemoved(const X509Certificate* cert) OVERRIDE {
    cert_db_->NotifyObserversOfCertRemoved(cert);
  }

  virtual void OnCertTrustChanged(const X509Certificate* cert) OVERRIDE {
    cert_db_->NotifyObserversOfCertTrustChanged(cert);
  }

 private:
  CertDatabase* cert_db_;

  DISALLOW_COPY_AND_ASSIGN(Notifier);
};

CertDatabase::CertDatabase()
    : observer_list_(new ObserverListThreadSafe<Observer>) {
  // Observe NSSCertDatabase events and forward them to observers of
  // CertDatabase. This also makes sure that NSS has been initialized.
  notifier_.reset(new Notifier(this));
}

CertDatabase::~CertDatabase() {}

int CertDatabase::CheckUserCert(X509Certificate* cert_obj) {
  if (!cert_obj)
    return ERR_CERT_INVALID;
  if (cert_obj->HasExpired())
    return ERR_CERT_DATE_INVALID;

  // Check if the private key corresponding to the certificate exist
  // We shouldn't accept any random client certificate sent by a CA.

  // Note: The NSS source documentation wrongly suggests that this
  // also imports the certificate if the private key exists. This
  // doesn't seem to be the case.

  CERTCertificate* cert = cert_obj->os_cert_handle();
  PK11SlotInfo* slot = PK11_KeyForCertExists(cert, NULL, NULL);
  if (!slot)
    return ERR_NO_PRIVATE_KEY_FOR_CERT;

  PK11_FreeSlot(slot);

  return OK;
}

int CertDatabase::AddUserCert(X509Certificate* cert_obj) {
  CERTCertificate* cert = cert_obj->os_cert_handle();
  CK_OBJECT_HANDLE key;
  crypto::ScopedPK11Slot slot(PK11_KeyForCertExists(cert, &key, NULL));
  if (!slot.get())
    return ERR_NO_PRIVATE_KEY_FOR_CERT;

  std::string nickname = x509_util::GetUniqueNicknameForSlot(
      cert_obj->GetDefaultNickname(USER_CERT),
      &cert->derSubject,
      slot.get());

  SECStatus rv;
  {
    crypto::AutoNSSWriteLock lock;
    rv = PK11_ImportCert(slot.get(), cert, key, nickname.c_str(), PR_FALSE);
  }

  if (rv != SECSuccess) {
    LOG(ERROR) << "Couldn't import user certificate. " << PORT_GetError();
    return ERR_ADD_USER_CERT_FAILED;
  }

  NotifyObserversOfCertAdded(cert_obj);
  return OK;
}

}  // namespace net