/* -*- 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/. */

#include "RootCertificateTelemetryUtils.h"

#include "mozilla/Logging.h"

#include "RootHashes.inc" // Note: Generated by genRootCAHashes.js

#include "ScopedNSSTypes.h"

#include "mozilla/ArrayUtils.h"

namespace mozilla { namespace psm {

mozilla::LazyLogModule gPublicKeyPinningTelemetryLog("PublicKeyPinningTelemetryService");

// Used in the BinarySearch method, this does a memcmp between the pointer

// provided to its construtor and whatever the binary search is looking for.

//

// This implementation assumes everything to be of HASH_LEN, so it should not

// be used generically.

class BinaryHashSearchArrayComparator

{

public:

  explicit BinaryHashSearchArrayComparator(const uint8_t* aTarget, size_t len)

    : mTarget(aTarget)

  {

    MOZ_ASSERT(len == HASH_LEN, "Hashes should be of the same length.");

  }

  int operator()(const CertAuthorityHash val) const {

    return memcmp(mTarget, val.hash, HASH_LEN);

  }

private:

  const uint8_t* mTarget;

};

// Perform a hash of the provided cert, then search in the RootHashes.inc data

// structure for a matching bin number.

int32_t

RootCABinNumber(const SECItem* cert)

{

  Digest digest;

  // Compute SHA256 hash of the certificate

  nsresult rv = digest.DigestBuf(SEC_OID_SHA256, cert->data, cert->len);

  if (NS_WARN_IF(NS_FAILED(rv))) {

    return ROOT_CERTIFICATE_HASH_FAILURE;

  }

  // Compare against list of stored hashes

  size_t idx;

  MOZ_LOG(gPublicKeyPinningTelemetryLog, LogLevel::Debug,

           ("pkpinTelem: First bytes %02x %02x %02x %02x\n",

            digest.get().data[0], digest.get().data[1], digest.get().data[2], digest.get().data[3]));

  if (mozilla::BinarySearchIf(ROOT_TABLE, 0, ArrayLength(ROOT_TABLE),

        BinaryHashSearchArrayComparator(static_cast<uint8_t*>(digest.get().data),

                                        digest.get().len),

        &idx)) {

    MOZ_LOG(gPublicKeyPinningTelemetryLog, LogLevel::Debug,

          ("pkpinTelem: Telemetry index was %zu, bin is %d\n",

           idx, ROOT_TABLE[idx].binNumber));

    return (int32_t) ROOT_TABLE[idx].binNumber;

  }

  // Didn't match.

  return ROOT_CERTIFICATE_UNKNOWN;

}

// Attempt to increment the appropriate bin in the provided Telemetry probe ID. If

// there was a hash failure, we do nothing.

void

AccumulateTelemetryForRootCA(mozilla::Telemetry::HistogramID probe,

  const CERTCertificate* cert)

{

  int32_t binId = RootCABinNumber(&cert->derCert);

  if (binId != ROOT_CERTIFICATE_HASH_FAILURE) {

    Accumulate(probe, binId);

  }

}

} // namespace psm

} // namespace mozilla