/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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/. */

#include "nsNSSCertificate.h"

#include "CertVerifier.h"
#include "ExtendedValidation.h"
#include "NSSCertDBTrustDomain.h"
#include "X509CertValidity.h"
#include "certdb.h"
#include "ipc/IPCMessageUtils.h"
#include "mozilla/Assertions.h"
#include "mozilla/Base64.h"
#include "mozilla/Casting.h"
#include "mozilla/NotNull.h"
#include "mozilla/Span.h"
#include "mozilla/TextUtils.h"
#include "mozilla/Unused.h"
#include "mozilla/ipc/TransportSecurityInfoUtils.h"
#include "mozilla/net/DNS.h"
#include "mozpkix/Result.h"
#include "mozpkix/pkixnss.h"
#include "mozpkix/pkixtypes.h"
#include "mozpkix/pkixutil.h"
#include "nsArray.h"
#include "nsCOMPtr.h"
#include "nsIClassInfoImpl.h"
#include "nsIObjectInputStream.h"
#include "nsIObjectOutputStream.h"
#include "nsIX509Cert.h"
#include "nsNSSCertHelper.h"
#include "nsNSSCertTrust.h"
#include "nsPK11TokenDB.h"
#include "nsPKCS12Blob.h"
#include "nsProxyRelease.h"
#include "nsReadableUtils.h"
#include "nsString.h"
#include "nsThreadUtils.h"
#include "nsUnicharUtils.h"
#include "nspr.h"
#include "prerror.h"
#include "secasn1.h"
#include "secder.h"
#include "secerr.h"
#include "ssl.h"

#ifdef XP_WIN
#  include <winsock.h>  // for htonl
#endif

using namespace mozilla;
using namespace mozilla::psm;

extern LazyLogModule gPIPNSSLog;

// This is being stored in an uint32_t that can otherwise
// only take values from nsIX509Cert's list of cert types.
// As nsIX509Cert is frozen, we choose a value not contained
// in the list to mean not yet initialized.
#define CERT_TYPE_NOT_YET_INITIALIZED (1 << 30)

NS_IMPL_ISUPPORTS(nsNSSCertificate, nsIX509Cert, nsISerializable, nsIClassInfo)

/*static*/
nsNSSCertificate* nsNSSCertificate::Create(CERTCertificate* cert) {
  if (cert)
    return new nsNSSCertificate(cert);
  else
    return new nsNSSCertificate();
}

nsNSSCertificate* nsNSSCertificate::ConstructFromDER(char* certDER,
                                                     int derLen) {
  nsNSSCertificate* newObject = nsNSSCertificate::Create();
  if (newObject && !newObject->InitFromDER(certDER, derLen)) {
    delete newObject;
    newObject = nullptr;
  }

  return newObject;
}

bool nsNSSCertificate::InitFromDER(char* certDER, int derLen) {
  if (!certDER || !derLen) return false;

  CERTCertificate* aCert = CERT_DecodeCertFromPackage(certDER, derLen);

  if (!aCert) {
#ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
    if (XRE_GetProcessType() == GeckoProcessType_Content) {
      MOZ_CRASH_UNSAFE_PRINTF("CERT_DecodeCertFromPackage failed in child: %d",
                              PR_GetError());
    }
#endif
    return false;
  }

  if (!aCert->dbhandle) {
    aCert->dbhandle = CERT_GetDefaultCertDB();
  }

  mCert.reset(aCert);
  return true;
}

nsNSSCertificate::nsNSSCertificate(CERTCertificate* cert)
    : mCert(nullptr), mCertType(CERT_TYPE_NOT_YET_INITIALIZED) {
  if (cert) {
    mCert.reset(CERT_DupCertificate(cert));
  }
}

nsNSSCertificate::nsNSSCertificate()
    : mCert(nullptr), mCertType(CERT_TYPE_NOT_YET_INITIALIZED) {}

static uint32_t getCertType(CERTCertificate* cert) {
  nsNSSCertTrust trust(cert->trust);
  if (cert->nickname && trust.HasAnyUser()) {
    return nsIX509Cert::USER_CERT;
  }
  if (trust.HasAnyCA()) {
    return nsIX509Cert::CA_CERT;
  }
  if (trust.HasPeer(true, false)) {
    return nsIX509Cert::SERVER_CERT;
  }
  if (trust.HasPeer(false, true) && cert->emailAddr) {
    return nsIX509Cert::EMAIL_CERT;
  }
  if (CERT_IsCACert(cert, nullptr)) {
    return nsIX509Cert::CA_CERT;
  }
  if (cert->emailAddr) {
    return nsIX509Cert::EMAIL_CERT;
  }
  return nsIX509Cert::UNKNOWN_CERT;
}

nsresult nsNSSCertificate::GetCertType(uint32_t* aCertType) {
  if (mCertType == CERT_TYPE_NOT_YET_INITIALIZED) {
    // only determine cert type once and cache it
    mCertType = getCertType(mCert.get());
  }
  *aCertType = mCertType;
  return NS_OK;
}

NS_IMETHODIMP
nsNSSCertificate::GetIsBuiltInRoot(bool* aIsBuiltInRoot) {
  NS_ENSURE_ARG(aIsBuiltInRoot);

  pkix::Result rv = IsCertBuiltInRoot(mCert.get(), *aIsBuiltInRoot);
  if (rv != pkix::Result::Success) {
    return NS_ERROR_FAILURE;
  }
  return NS_OK;
}

/**
 * Appends a pipnss bundle string to the given string.
 *
 * @param bundleKey Key for the string to append.
 * @param currentText The text to append to, using commas as separators.
 */
template <size_t N>
void AppendBundleStringCommaSeparated(const char (&bundleKey)[N],
                                      /*in/out*/ nsAString& currentText) {
  nsAutoString bundleString;
  nsresult rv = GetPIPNSSBundleString(bundleKey, bundleString);
  if (NS_FAILED(rv)) {
    return;
  }

  if (!currentText.IsEmpty()) {
    currentText.Append(',');
  }
  currentText.Append(bundleString);
}

NS_IMETHODIMP
nsNSSCertificate::GetKeyUsages(nsAString& text) {
  text.Truncate();

  if (!mCert) {
    return NS_ERROR_FAILURE;
  }

  if (!mCert->extensions) {
    return NS_OK;
  }

  ScopedAutoSECItem keyUsageItem;
  if (CERT_FindKeyUsageExtension(mCert.get(), &keyUsageItem) != SECSuccess) {
    return PORT_GetError() == SEC_ERROR_EXTENSION_NOT_FOUND ? NS_OK
                                                            : NS_ERROR_FAILURE;
  }

  unsigned char keyUsage = 0;
  if (keyUsageItem.len) {
    keyUsage = keyUsageItem.data[0];
  }

  if (keyUsage & KU_DIGITAL_SIGNATURE) {
    AppendBundleStringCommaSeparated("CertDumpKUSign", text);
  }
  if (keyUsage & KU_NON_REPUDIATION) {
    AppendBundleStringCommaSeparated("CertDumpKUNonRep", text);
  }
  if (keyUsage & KU_KEY_ENCIPHERMENT) {
    AppendBundleStringCommaSeparated("CertDumpKUEnc", text);
  }
  if (keyUsage & KU_DATA_ENCIPHERMENT) {
    AppendBundleStringCommaSeparated("CertDumpKUDEnc", text);
  }
  if (keyUsage & KU_KEY_AGREEMENT) {
    AppendBundleStringCommaSeparated("CertDumpKUKA", text);
  }
  if (keyUsage & KU_KEY_CERT_SIGN) {
    AppendBundleStringCommaSeparated("CertDumpKUCertSign", text);
  }
  if (keyUsage & KU_CRL_SIGN) {
    AppendBundleStringCommaSeparated("CertDumpKUCRLSign", text);
  }

  return NS_OK;
}

NS_IMETHODIMP
nsNSSCertificate::GetDbKey(nsACString& aDbKey) {
  static_assert(sizeof(uint64_t) == 8, "type size consistency check");
  static_assert(sizeof(uint32_t) == 4, "type size consistency check");

  pkix::Input certInput;
  pkix::Result result = certInput.Init(mCert->derCert.data, mCert->derCert.len);
  if (result != pkix::Result::Success) {
    return NS_ERROR_INVALID_ARG;
  }
  // NB: since we're not building a trust path, the endEntityOrCA parameter is
  // irrelevant.
  pkix::BackCert cert(certInput, pkix::EndEntityOrCA::MustBeEndEntity, nullptr);
  result = cert.Init();
  if (result != pkix::Result::Success) {
    return NS_ERROR_INVALID_ARG;
  }

  // The format of the key is the base64 encoding of the following:
  // 4 bytes: {0, 0, 0, 0} (this was intended to be the module ID, but it was
  //                        never implemented)
  // 4 bytes: {0, 0, 0, 0} (this was intended to be the slot ID, but it was
  //                        never implemented)
  // 4 bytes: <serial number length in big-endian order>
  // 4 bytes: <DER-encoded issuer distinguished name length in big-endian order>
  // n bytes: <bytes of serial number>
  // m bytes: <DER-encoded issuer distinguished name>
  nsAutoCString buf;
  const char leadingZeroes[] = {0, 0, 0, 0, 0, 0, 0, 0};
  buf.Append(leadingZeroes, sizeof(leadingZeroes));
  uint32_t serialNumberLen = htonl(cert.GetSerialNumber().GetLength());
  buf.Append(BitwiseCast<const char*, const uint32_t*>(&serialNumberLen),
             sizeof(uint32_t));
  uint32_t issuerLen = htonl(cert.GetIssuer().GetLength());
  buf.Append(BitwiseCast<const char*, const uint32_t*>(&issuerLen),
             sizeof(uint32_t));
  buf.Append(BitwiseCast<const char*, const unsigned char*>(
                 cert.GetSerialNumber().UnsafeGetData()),
             cert.GetSerialNumber().GetLength());
  buf.Append(BitwiseCast<const char*, const unsigned char*>(
                 cert.GetIssuer().UnsafeGetData()),
             cert.GetIssuer().GetLength());

  return Base64Encode(buf, aDbKey);
}

NS_IMETHODIMP
nsNSSCertificate::GetDisplayName(nsAString& aDisplayName) {
  aDisplayName.Truncate();

  MOZ_ASSERT(mCert, "mCert should not be null in GetDisplayName");
  if (!mCert) {
    return NS_ERROR_FAILURE;
  }

  UniquePORTString commonName(CERT_GetCommonName(&mCert->subject));
  UniquePORTString organizationalUnitName(CERT_GetOrgUnitName(&mCert->subject));
  UniquePORTString organizationName(CERT_GetOrgName(&mCert->subject));

  bool isBuiltInRoot;
  nsresult rv = GetIsBuiltInRoot(&isBuiltInRoot);
  if (NS_FAILED(rv)) {
    return rv;
  }

  // Only use the nickname for built-in roots where we already have a hard-coded
  // reasonable display name (unfortunately we have to strip off the leading
  // slot identifier followed by a ':'). Otherwise, attempt to use the following
  // in order:
  //  - the common name, if present
  //  - an organizational unit name, if present
  //  - an organization name, if present
  //  - the entire subject distinguished name, if non-empty
  //  - an email address, if one can be found
  // In the unlikely event that none of these fields are present and non-empty
  // (the subject really shouldn't be empty), an empty string is returned.
  nsAutoCString builtInRootNickname;
  if (isBuiltInRoot) {
    nsAutoCString fullNickname(mCert->nickname);
    int32_t index = fullNickname.Find(":");
    if (index != kNotFound) {
      // Substring will gracefully handle the case where index is the last
      // character in the string (that is, if the nickname is just
      // "Builtin Object Token:"). In that case, we'll get an empty string.
      builtInRootNickname =
          Substring(fullNickname, AssertedCast<uint32_t>(index + 1));
    }
  }
  const char* nameOptions[] = {
      builtInRootNickname.get(),    commonName.get(),
      organizationalUnitName.get(), organizationName.get(),
      mCert->subjectName,           mCert->emailAddr};

  for (auto nameOption : nameOptions) {
    if (nameOption) {
      size_t len = strlen(nameOption);
      if (len > 0) {
        LossyUTF8ToUTF16(nameOption, len, aDisplayName);
        return NS_OK;
      }
    }
  }

  return NS_OK;
}

NS_IMETHODIMP
nsNSSCertificate::GetEmailAddress(nsAString& aEmailAddress) {
  if (mCert->emailAddr) {
    CopyUTF8toUTF16(MakeStringSpan(mCert->emailAddr), aEmailAddress);
  } else {
    GetPIPNSSBundleString("CertNoEmailAddress", aEmailAddress);
  }
  return NS_OK;
}

NS_IMETHODIMP
nsNSSCertificate::GetEmailAddresses(nsTArray<nsString>& aAddresses) {
  uint32_t length = 0;
  for (const char* aAddr = CERT_GetFirstEmailAddress(mCert.get()); aAddr;
       aAddr = CERT_GetNextEmailAddress(mCert.get(), aAddr)) {
    ++(length);
  }

  aAddresses.SetCapacity(length);

  for (const char* aAddr = CERT_GetFirstEmailAddress(mCert.get()); aAddr;
       aAddr = CERT_GetNextEmailAddress(mCert.get(), aAddr)) {
    CopyASCIItoUTF16(MakeStringSpan(aAddr), *aAddresses.AppendElement());
  }

  return NS_OK;
}

NS_IMETHODIMP
nsNSSCertificate::ContainsEmailAddress(const nsAString& aEmailAddress,
                                       bool* result) {
  NS_ENSURE_ARG(result);
  *result = false;

  for (const char* aAddr = CERT_GetFirstEmailAddress(mCert.get()); aAddr;
       aAddr = CERT_GetNextEmailAddress(mCert.get(), aAddr)) {
    nsAutoString certAddr;
    LossyUTF8ToUTF16(aAddr, strlen(aAddr), certAddr);
    ToLowerCase(certAddr);

    nsAutoString testAddr(aEmailAddress);
    ToLowerCase(testAddr);

    if (certAddr == testAddr) {
      *result = true;
      break;
    }
  }

  return NS_OK;
}

NS_IMETHODIMP
nsNSSCertificate::GetCommonName(nsAString& aCommonName) {
  aCommonName.Truncate();
  if (mCert) {
    UniquePORTString commonName(CERT_GetCommonName(&mCert->subject));
    if (commonName) {
      LossyUTF8ToUTF16(commonName.get(), strlen(commonName.get()), aCommonName);
    }
  }
  return NS_OK;
}

NS_IMETHODIMP
nsNSSCertificate::GetOrganization(nsAString& aOrganization) {
  aOrganization.Truncate();
  if (mCert) {
    UniquePORTString organization(CERT_GetOrgName(&mCert->subject));
    if (organization) {
      LossyUTF8ToUTF16(organization.get(), strlen(organization.get()),
                       aOrganization);
    }
  }
  return NS_OK;
}

NS_IMETHODIMP
nsNSSCertificate::GetIssuerCommonName(nsAString& aCommonName) {
  aCommonName.Truncate();
  if (mCert) {
    UniquePORTString commonName(CERT_GetCommonName(&mCert->issuer));
    if (commonName) {
      LossyUTF8ToUTF16(commonName.get(), strlen(commonName.get()), aCommonName);
    }
  }
  return NS_OK;
}

NS_IMETHODIMP
nsNSSCertificate::GetIssuerOrganization(nsAString& aOrganization) {
  aOrganization.Truncate();
  if (mCert) {
    UniquePORTString organization(CERT_GetOrgName(&mCert->issuer));
    if (organization) {
      LossyUTF8ToUTF16(organization.get(), strlen(organization.get()),
                       aOrganization);
    }
  }
  return NS_OK;
}

NS_IMETHODIMP
nsNSSCertificate::GetIssuerOrganizationUnit(nsAString& aOrganizationUnit) {
  aOrganizationUnit.Truncate();
  if (mCert) {
    UniquePORTString organizationUnit(CERT_GetOrgUnitName(&mCert->issuer));
    if (organizationUnit) {
      LossyUTF8ToUTF16(organizationUnit.get(), strlen(organizationUnit.get()),
                       aOrganizationUnit);
    }
  }
  return NS_OK;
}

NS_IMETHODIMP
nsNSSCertificate::GetOrganizationalUnit(nsAString& aOrganizationalUnit) {
  aOrganizationalUnit.Truncate();
  if (mCert) {
    UniquePORTString orgunit(CERT_GetOrgUnitName(&mCert->subject));
    if (orgunit) {
      LossyUTF8ToUTF16(orgunit.get(), strlen(orgunit.get()),
                       aOrganizationalUnit);
    }
  }
  return NS_OK;
}

NS_IMETHODIMP
nsNSSCertificate::GetSubjectName(nsAString& _subjectName) {
  _subjectName.Truncate();
  if (mCert->subjectName) {
    LossyUTF8ToUTF16(mCert->subjectName, strlen(mCert->subjectName),
                     _subjectName);
  }
  return NS_OK;
}

NS_IMETHODIMP
nsNSSCertificate::GetIssuerName(nsAString& _issuerName) {
  _issuerName.Truncate();
  if (mCert->issuerName) {
    LossyUTF8ToUTF16(mCert->issuerName, strlen(mCert->issuerName), _issuerName);
  }
  return NS_OK;
}

NS_IMETHODIMP
nsNSSCertificate::GetSerialNumber(nsAString& _serialNumber) {
  _serialNumber.Truncate();
  UniquePORTString tmpstr(
      CERT_Hexify(&mCert->serialNumber, true /* use colon delimiters */));
  if (tmpstr) {
    _serialNumber = NS_ConvertASCIItoUTF16(tmpstr.get());
    return NS_OK;
  }
  return NS_ERROR_FAILURE;
}

nsresult nsNSSCertificate::GetCertificateHash(nsAString& aFingerprint,
                                              SECOidTag aHashAlg) {
  aFingerprint.Truncate();
  nsTArray<uint8_t> digestArray;
  nsresult rv = Digest::DigestBuf(aHashAlg, mCert->derCert.data,
                                  mCert->derCert.len, digestArray);
  if (NS_FAILED(rv)) {
    return rv;
  }
  SECItem digestItem = {siBuffer, digestArray.Elements(),
                        static_cast<unsigned int>(digestArray.Length())};

  UniquePORTString fpStr(
      CERT_Hexify(&digestItem, true /* use colon delimiters */));
  if (!fpStr) {
    return NS_ERROR_FAILURE;
  }

  aFingerprint.AssignASCII(fpStr.get());
  return NS_OK;
}

NS_IMETHODIMP
nsNSSCertificate::GetSha256Fingerprint(nsAString& aSha256Fingerprint) {
  return GetCertificateHash(aSha256Fingerprint, SEC_OID_SHA256);
}

NS_IMETHODIMP
nsNSSCertificate::GetSha1Fingerprint(nsAString& _sha1Fingerprint) {
  return GetCertificateHash(_sha1Fingerprint, SEC_OID_SHA1);
}

NS_IMETHODIMP
nsNSSCertificate::GetTokenName(nsAString& aTokenName) {
  MOZ_ASSERT(mCert);
  if (!mCert) {
    return NS_ERROR_FAILURE;
  }
  UniquePK11SlotInfo internalSlot(PK11_GetInternalSlot());
  if (!internalSlot) {
    return NS_ERROR_FAILURE;
  }
  nsCOMPtr<nsIPK11Token> token(
      new nsPK11Token(mCert->slot ? mCert->slot : internalSlot.get()));
  nsAutoCString tmp;
  nsresult rv = token->GetTokenName(tmp);
  if (NS_FAILED(rv)) {
    return rv;
  }
  aTokenName.Assign(NS_ConvertUTF8toUTF16(tmp));
  return NS_OK;
}

NS_IMETHODIMP
nsNSSCertificate::GetSha256SubjectPublicKeyInfoDigest(
    nsACString& aSha256SPKIDigest) {
  aSha256SPKIDigest.Truncate();

  pkix::Input certInput;
  pkix::Result result = certInput.Init(mCert->derCert.data, mCert->derCert.len);
  if (result != pkix::Result::Success) {
    return NS_ERROR_INVALID_ARG;
  }
  // NB: since we're not building a trust path, the endEntityOrCA parameter is
  // irrelevant.
  pkix::BackCert cert(certInput, pkix::EndEntityOrCA::MustBeEndEntity, nullptr);
  result = cert.Init();
  if (result != pkix::Result::Success) {
    return NS_ERROR_INVALID_ARG;
  }
  pkix::Input derPublicKey = cert.GetSubjectPublicKeyInfo();
  nsTArray<uint8_t> digestArray;
  nsresult rv = Digest::DigestBuf(SEC_OID_SHA256, derPublicKey.UnsafeGetData(),
                                  derPublicKey.GetLength(), digestArray);
  if (NS_FAILED(rv)) {
    return rv;
  }
  rv = Base64Encode(nsDependentCSubstring(
                        BitwiseCast<char*, uint8_t*>(digestArray.Elements()),
                        digestArray.Length()),
                    aSha256SPKIDigest);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }
  return NS_OK;
}

NS_IMETHODIMP
nsNSSCertificate::GetRawDER(nsTArray<uint8_t>& aArray) {
  if (mCert) {
    aArray.SetLength(mCert->derCert.len);
    memcpy(aArray.Elements(), mCert->derCert.data, mCert->derCert.len);
    return NS_OK;
  }
  return NS_ERROR_FAILURE;
}

NS_IMETHODIMP
nsNSSCertificate::GetBase64DERString(nsACString& base64DERString) {
  nsDependentCSubstring derString(
      reinterpret_cast<const char*>(mCert->derCert.data), mCert->derCert.len);

  nsresult rv = Base64Encode(derString, base64DERString);

  if (NS_FAILED(rv)) {
    return rv;
  }

  return NS_OK;
}

CERTCertificate* nsNSSCertificate::GetCert() {
  return (mCert) ? CERT_DupCertificate(mCert.get()) : nullptr;
}

NS_IMETHODIMP
nsNSSCertificate::GetValidity(nsIX509CertValidity** aValidity) {
  NS_ENSURE_ARG(aValidity);
  if (!mCert) {
    return NS_ERROR_FAILURE;
  }
  pkix::Input certInput;
  pkix::Result rv = certInput.Init(mCert->derCert.data, mCert->derCert.len);
  if (rv != pkix::Success) {
    return NS_ERROR_FAILURE;
  }
  nsCOMPtr<nsIX509CertValidity> validity = new X509CertValidity(certInput);
  validity.forget(aValidity);
  return NS_OK;
}

NS_IMETHODIMP
nsNSSCertificate::Equals(nsIX509Cert* other, bool* result) {
  NS_ENSURE_ARG(other);
  NS_ENSURE_ARG(result);

  UniqueCERTCertificate cert(other->GetCert());
  *result = (mCert.get() == cert.get());
  return NS_OK;
}

namespace mozilla {

// TODO(bug 1036065): It seems like we only construct CERTCertLists for the
// purpose of constructing nsNSSCertLists, so maybe we should change this
// function to output an nsNSSCertList instead.
SECStatus ConstructCERTCertListFromReversedDERArray(
    const mozilla::pkix::DERArray& certArray,
    /*out*/ UniqueCERTCertList& certList) {
  certList = UniqueCERTCertList(CERT_NewCertList());
  if (!certList) {
    return SECFailure;
  }

  CERTCertDBHandle* certDB(CERT_GetDefaultCertDB());  // non-owning

  size_t numCerts = certArray.GetLength();
  for (size_t i = 0; i < numCerts; ++i) {
    SECItem certDER(UnsafeMapInputToSECItem(*certArray.GetDER(i)));
    UniqueCERTCertificate cert(
        CERT_NewTempCertificate(certDB, &certDER, nullptr, false, true));
    if (!cert) {
      return SECFailure;
    }
    // certArray is ordered with the root first, but we want the resulting
    // certList to have the root last.
    if (CERT_AddCertToListHead(certList.get(), cert.get()) != SECSuccess) {
      return SECFailure;
    }
    Unused << cert.release();  // cert is now owned by certList.
  }

  return SECSuccess;
}

}  // namespace mozilla

nsresult nsNSSCertificate::SegmentCertificateChain(
    /* in */ const nsTArray<RefPtr<nsIX509Cert>>& aCertList,
    /* out */ nsCOMPtr<nsIX509Cert>& aRoot,
    /* out */ nsTArray<RefPtr<nsIX509Cert>>& aIntermediates,
    /* out */ nsCOMPtr<nsIX509Cert>& aEndEntity) {
  if (aRoot || aEndEntity) {
    // All passed-in nsCOMPtrs should be empty for the state machine to work
    return NS_ERROR_UNEXPECTED;
  }

  if (!aIntermediates.IsEmpty()) {
    return NS_ERROR_INVALID_ARG;
  }

  for (size_t i = 0; i < aCertList.Length(); ++i) {
    const auto& cert = aCertList[i];
    if (!aEndEntity) {
      aEndEntity = cert;
    } else if (i == aCertList.Length() - 1) {
      aRoot = cert;
    } else {
      // One of (potentially many) intermediates
      aIntermediates.AppendElement(cert);
    }
  }

  if (!aRoot || !aEndEntity) {
    // No self-signed (or empty) chains allowed
    return NS_ERROR_INVALID_ARG;
  }

  return NS_OK;
}

nsresult nsNSSCertificate::GetRootCertificate(
    /* in */ const nsTArray<RefPtr<nsIX509Cert>>& aCertList,
    /* out */ nsCOMPtr<nsIX509Cert>& aRoot) {
  if (aRoot) {
    return NS_ERROR_UNEXPECTED;
  }
  // If the list is empty, leave aRoot empty.
  if (aCertList.IsEmpty()) {
    return NS_ERROR_FAILURE;
  }

  nsCOMPtr<nsIX509Cert> cert(aCertList.LastElement());
  aRoot = cert;
  if (!aRoot) {
    return NS_ERROR_OUT_OF_MEMORY;
  }
  return NS_OK;
}

// NB: Any updates (except disk-only fields) must be kept in sync with
//     |SerializeToIPC|.
NS_IMETHODIMP
nsNSSCertificate::Write(nsIObjectOutputStream* aStream) {
  NS_ENSURE_STATE(mCert);
  // This field used to be the cached EV status, but it is no longer necessary.
  nsresult rv = aStream->Write32(0);
  if (NS_FAILED(rv)) {
    return rv;
  }
  rv = aStream->Write32(mCert->derCert.len);
  if (NS_FAILED(rv)) {
    return rv;
  }
  return aStream->WriteBytes(
      AsBytes(Span(mCert->derCert.data, mCert->derCert.len)));
}

// NB: Any updates (except disk-only fields) must be kept in sync with
//     |DeserializeFromIPC|.
NS_IMETHODIMP
nsNSSCertificate::Read(nsIObjectInputStream* aStream) {
  NS_ENSURE_STATE(!mCert);

  // This field is no longer used.
  uint32_t unusedCachedEVStatus;
  nsresult rv = aStream->Read32(&unusedCachedEVStatus);
  if (NS_FAILED(rv)) {
    return rv;
  }

  uint32_t len;
  rv = aStream->Read32(&len);
  if (NS_FAILED(rv)) {
    return rv;
  }

  nsCString str;
  rv = aStream->ReadBytes(len, getter_Copies(str));
  if (NS_FAILED(rv)) {
    return rv;
  }

  if (!InitFromDER(const_cast<char*>(str.get()), len)) {
    return NS_ERROR_UNEXPECTED;
  }

  return NS_OK;
}

void nsNSSCertificate::SerializeToIPC(IPC::Message* aMsg) {
  bool hasCert = static_cast<bool>(mCert);
  WriteParam(aMsg, hasCert);

  if (!hasCert) {
    return;
  }

  const nsDependentCSubstring certBytes(
      reinterpret_cast<char*>(mCert->derCert.data), mCert->derCert.len);

  WriteParam(aMsg, certBytes);
}

bool nsNSSCertificate::DeserializeFromIPC(const IPC::Message* aMsg,
                                          PickleIterator* aIter) {
  bool hasCert = false;
  if (!ReadParam(aMsg, aIter, &hasCert)) {
    return false;
  }

  if (!hasCert) {
    return true;
  }

  nsCString derBytes;
  if (!ReadParam(aMsg, aIter, &derBytes)) {
    return false;
  }

  if (derBytes.Length() == 0) {
    return false;
  }

  // NSS accepts a |char*| here, but doesn't modify the contents of the array
  // and casts it back to an |unsigned char*|.
  return InitFromDER(const_cast<char*>(derBytes.get()), derBytes.Length());
}

NS_IMETHODIMP
nsNSSCertificate::GetInterfaces(nsTArray<nsIID>& array) {
  array.Clear();
  return NS_OK;
}

NS_IMETHODIMP
nsNSSCertificate::GetScriptableHelper(nsIXPCScriptable** _retval) {
  *_retval = nullptr;
  return NS_OK;
}

NS_IMETHODIMP
nsNSSCertificate::GetContractID(nsACString& aContractID) {
  aContractID.SetIsVoid(true);
  return NS_OK;
}

NS_IMETHODIMP
nsNSSCertificate::GetClassDescription(nsACString& aClassDescription) {
  aClassDescription.SetIsVoid(true);
  return NS_OK;
}

NS_IMETHODIMP
nsNSSCertificate::GetClassID(nsCID** aClassID) {
  *aClassID = (nsCID*)moz_xmalloc(sizeof(nsCID));
  return GetClassIDNoAlloc(*aClassID);
}

NS_IMETHODIMP
nsNSSCertificate::GetFlags(uint32_t* aFlags) {
  *aFlags = nsIClassInfo::THREADSAFE;
  return NS_OK;
}

NS_IMETHODIMP
nsNSSCertificate::GetClassIDNoAlloc(nsCID* aClassIDNoAlloc) {
  static NS_DEFINE_CID(kNSSCertificateCID, NS_X509CERT_CID);

  *aClassIDNoAlloc = kNSSCertificateCID;
  return NS_OK;
}