DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Header

Mercurial (f313a52c45bf)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182
/* -*- 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 "MultiLogCTVerifier.h"

#include "CTObjectsExtractor.h"
#include "CTSerialization.h"

namespace mozilla {
namespace ct {

using namespace mozilla::pkix;

// Note: this moves |verifiedSct| to the target list in |result|.
static void StoreVerifiedSct(CTVerifyResult& result, VerifiedSCT&& verifiedSct,
                             VerifiedSCT::Status status) {
  verifiedSct.status = status;
  result.verifiedScts.push_back(std::move(verifiedSct));
}

void MultiLogCTVerifier::AddLog(CTLogVerifier&& log) {
  mLogs.push_back(std::move(log));
}

Result MultiLogCTVerifier::Verify(Input cert, Input issuerSubjectPublicKeyInfo,
                                  Input sctListFromCert,
                                  Input sctListFromOCSPResponse,
                                  Input sctListFromTLSExtension, Time time,
                                  CTVerifyResult& result) {
  assert(cert.GetLength() > 0);
  result.Reset();

  Result rv;

  // Verify embedded SCTs
  if (issuerSubjectPublicKeyInfo.GetLength() > 0 &&
      sctListFromCert.GetLength() > 0) {
    LogEntry precertEntry;
    rv = GetPrecertLogEntry(cert, issuerSubjectPublicKeyInfo, precertEntry);
    if (rv != Success) {
      return rv;
    }
    rv = VerifySCTs(sctListFromCert, precertEntry,
                    VerifiedSCT::Origin::Embedded, time, result);
    if (rv != Success) {
      return rv;
    }
  }

  LogEntry x509Entry;
  GetX509LogEntry(cert, x509Entry);

  // Verify SCTs from a stapled OCSP response
  if (sctListFromOCSPResponse.GetLength() > 0) {
    rv = VerifySCTs(sctListFromOCSPResponse, x509Entry,
                    VerifiedSCT::Origin::OCSPResponse, time, result);
    if (rv != Success) {
      return rv;
    }
  }

  // Verify SCTs from a TLS extension
  if (sctListFromTLSExtension.GetLength() > 0) {
    rv = VerifySCTs(sctListFromTLSExtension, x509Entry,
                    VerifiedSCT::Origin::TLSExtension, time, result);
    if (rv != Success) {
      return rv;
    }
  }
  return Success;
}

Result MultiLogCTVerifier::VerifySCTs(Input encodedSctList,
                                      const LogEntry& expectedEntry,
                                      VerifiedSCT::Origin origin, Time time,
                                      CTVerifyResult& result) {
  Reader listReader;
  Result rv = DecodeSCTList(encodedSctList, listReader);
  if (rv != Success) {
    result.decodingErrors++;
    return Success;
  }

  while (!listReader.AtEnd()) {
    Input encodedSct;
    rv = ReadSCTListItem(listReader, encodedSct);
    if (rv != Success) {
      result.decodingErrors++;
      return Success;
    }

    Reader encodedSctReader(encodedSct);
    SignedCertificateTimestamp sct;
    rv = DecodeSignedCertificateTimestamp(encodedSctReader, sct);
    if (rv != Success) {
      result.decodingErrors++;
      continue;
    }

    rv = VerifySingleSCT(std::move(sct), expectedEntry, origin, time, result);
    if (rv != Success) {
      return rv;
    }
  }
  return Success;
}

Result MultiLogCTVerifier::VerifySingleSCT(SignedCertificateTimestamp&& sct,
                                           const LogEntry& expectedEntry,
                                           VerifiedSCT::Origin origin,
                                           Time time, CTVerifyResult& result) {
  VerifiedSCT verifiedSct;
  verifiedSct.origin = origin;
  verifiedSct.sct = std::move(sct);

  CTLogVerifier* matchingLog = nullptr;
  for (auto& log : mLogs) {
    if (log.keyId() == verifiedSct.sct.logId) {
      matchingLog = &log;
      break;
    }
  }

  if (!matchingLog) {
    // SCT does not match any known log.
    StoreVerifiedSct(result, std::move(verifiedSct),
                     VerifiedSCT::Status::UnknownLog);
    return Success;
  }

  verifiedSct.logOperatorId = matchingLog->operatorId();

  if (!matchingLog->SignatureParametersMatch(verifiedSct.sct.signature)) {
    // SCT signature parameters do not match the log's.
    StoreVerifiedSct(result, std::move(verifiedSct),
                     VerifiedSCT::Status::InvalidSignature);
    return Success;
  }

  Result rv = matchingLog->Verify(expectedEntry, verifiedSct.sct);
  if (rv != Success) {
    if (rv == Result::ERROR_BAD_SIGNATURE) {
      StoreVerifiedSct(result, std::move(verifiedSct),
                       VerifiedSCT::Status::InvalidSignature);
      return Success;
    }
    return rv;
  }

  // Make sure the timestamp is legitimate (not in the future).
  // SCT's |timestamp| is measured in milliseconds since the epoch,
  // ignoring leap seconds. When converting it to a second-level precision
  // pkix::Time, we need to round it either up or down. In our case, rounding up
  // (towards the future) is more "secure", although practically
  // it does not matter.
  Time sctTime =
      TimeFromEpochInSeconds((verifiedSct.sct.timestamp + 999u) / 1000u);
  if (sctTime > time) {
    StoreVerifiedSct(result, std::move(verifiedSct),
                     VerifiedSCT::Status::InvalidTimestamp);
    return Success;
  }

  // SCT verified ok, see if the log is qualified. Since SCTs from
  // disqualified logs are treated as valid under certain circumstances (see
  // the CT Policy), the log qualification check must be the last one we do.
  if (matchingLog->isDisqualified()) {
    verifiedSct.logDisqualificationTime = matchingLog->disqualificationTime();
    StoreVerifiedSct(result, std::move(verifiedSct),
                     VerifiedSCT::Status::ValidFromDisqualifiedLog);
    return Success;
  }

  StoreVerifiedSct(result, std::move(verifiedSct), VerifiedSCT::Status::Valid);
  return Success;
}

}  // namespace ct
}  // namespace mozilla