/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef TrustOverrides_h
#define TrustOverrides_h

#include "nsNSSCertificate.h"
#include "nsNSSCertValidity.h"
#include "mozilla/ArrayUtils.h"

using namespace mozilla;

struct DataAndLength {
  const uint8_t* data;
  uint32_t len;
};

template<size_t T>
static bool
CertDNIsInList(const CERTCertificate* aCert, const DataAndLength (&aDnList)[T])
{
  MOZ_ASSERT(aCert);
  if (!aCert) {
    return false;
  }

  for (auto& dn: aDnList) {
    if (aCert->derSubject.len == dn.len &&
        mozilla::ArrayEqual(aCert->derSubject.data, dn.data, dn.len)) {
      return true;
    }
  }
  return false;
}

template<size_t T>
static bool
CertSPKIIsInList(const CERTCertificate* aCert, const DataAndLength (&aSpkiList)[T])
{
  MOZ_ASSERT(aCert);
  if (!aCert) {
    return false;
  }

  for (auto& spki: aSpkiList) {
    if (aCert->derPublicKey.len == spki.len &&
        mozilla::ArrayEqual(aCert->derPublicKey.data, spki.data, spki.len)) {
      return true;
    }
  }
  return false;
}

template<size_t T, size_t R>
static bool
CertMatchesStaticData(const CERTCertificate* cert,
                      const unsigned char (&subject)[T],
                      const unsigned char (&spki)[R]) {
  MOZ_ASSERT(cert);
  if (!cert) {
    return false;
  }
  return cert->derSubject.len == T &&
         mozilla::ArrayEqual(cert->derSubject.data, subject, T) &&
         cert->derPublicKey.len == R &&
         mozilla::ArrayEqual(cert->derPublicKey.data, spki, R);
}

// Implements the graduated Symantec distrust algorithm from Bug 1409257.
// This accepts a pre-segmented certificate chain (e.g. SegmentCertificateChain)
// as |intCerts| and |eeCert|, and pre-assumes that the root has been identified
// as being affected (this is to avoid duplicate Segment operations in the
// NSSCertDBTrustDomain). If |permitAfterDate| is non-zero, this algorithm
// returns "not distrusted" if the NotBefore date of |eeCert| is after
// the |permitAfterDate|. Then each of the |intCerts| is evaluated against a
// |whitelist| of SPKI entries, and if a match is found, then this returns
// "not distrusted." Otherwise, due to the precondition holding, the chain is
// "distrusted."
template<size_t T>
static nsresult
CheckForSymantecDistrust(const nsCOMPtr<nsIX509CertList>& intCerts,
                         const nsCOMPtr<nsIX509Cert>& eeCert,
                         const PRTime& permitAfterDate,
                         const DataAndLength (&whitelist)[T],
                         /* out */ bool& isDistrusted)
{
    // PRECONDITION: The rootCert is already verified as being one of the
    // affected Symantec roots

    // Check the preference to see if this is enabled before proceeding.
    // TODO in Bug 1437754

    isDistrusted = true;

    // Only check the validity period if we're asked
    if (permitAfterDate > 0) {
      // We need to verify the age of the end entity
      nsCOMPtr<nsIX509CertValidity> validity;
      nsresult rv = eeCert->GetValidity(getter_AddRefs(validity));
      if (NS_FAILED(rv)) {
        return rv;
      }

      PRTime notBefore;
      rv = validity->GetNotBefore(&notBefore);
      if (NS_FAILED(rv)) {
        return rv;
      }

      // If the end entity's notBefore date is after the permitAfter date, this
      // algorithm doesn't apply, so exit false before we do any iterating.
      if (notBefore >= permitAfterDate) {
        isDistrusted = false;
        return NS_OK;
      }
    }

    // Look for one of the intermediates to be in the whitelist
    RefPtr<nsNSSCertList> intCertList = intCerts->GetCertList();

    return intCertList->ForEachCertificateInChain(
      [&isDistrusted, &whitelist] (nsCOMPtr<nsIX509Cert> aCert, bool aHasMore,
                                   /* out */ bool& aContinue) {
        // We need an owning handle when calling nsIX509Cert::GetCert().
        UniqueCERTCertificate nssCert(aCert->GetCert());
        if (CertSPKIIsInList(nssCert.get(), whitelist)) {
          // In the whitelist
          isDistrusted = false;
          aContinue = false;
        }
        return NS_OK;
    });
}

#endif // TrustOverrides_h