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/* -*- 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"
#include "mozilla/Assertions.h"
#include "mozilla/Move.h"
namespace mozilla { namespace ct {
using namespace mozilla::pkix;
// Note: this moves |sct| to the target list in |result|, invalidating |sct|.
static Result
StoreVerifiedSct(CTVerifyResult& result,
SignedCertificateTimestamp&& sct,
SignedCertificateTimestamp::VerificationStatus status)
{
sct.verificationStatus = status;
if (!result.scts.append(Move(sct))) {
return Result::FATAL_ERROR_NO_MEMORY;
}
return Success;
}
Result
MultiLogCTVerifier::AddLog(Input publicKey)
{
CTLogVerifier log;
Result rv = log.Init(publicKey);
if (rv != Success) {
return rv;
}
if (!mLogs.append(Move(log))) {
return Result::FATAL_ERROR_NO_MEMORY;
}
return Success;
}
Result
MultiLogCTVerifier::Verify(Input cert,
Input issuerSubjectPublicKeyInfo,
Input sctListFromCert,
Input sctListFromOCSPResponse,
Input sctListFromTLSExtension,
Time time,
CTVerifyResult& result)
{
MOZ_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,
SignedCertificateTimestamp::Origin::Embedded, time,
result);
if (rv != Success) {
return rv;
}
}
LogEntry x509Entry;
rv = GetX509LogEntry(cert, x509Entry);
if (rv != Success) {
return rv;
}
// Verify SCTs from a stapled OCSP response
if (sctListFromOCSPResponse.GetLength() > 0) {
rv = VerifySCTs(sctListFromOCSPResponse, x509Entry,
SignedCertificateTimestamp::Origin::OCSPResponse, time,
result);
if (rv != Success) {
return rv;
}
}
// Verify SCTs from a TLS extension
if (sctListFromTLSExtension.GetLength() > 0) {
rv = VerifySCTs(sctListFromTLSExtension, x509Entry,
SignedCertificateTimestamp::Origin::TLSExtension, time,
result);
if (rv != Success) {
return rv;
}
}
return Success;
}
Result
MultiLogCTVerifier::VerifySCTs(Input encodedSctList,
const LogEntry& expectedEntry,
SignedCertificateTimestamp::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;
}
sct.origin = origin;
rv = VerifySingleSCT(Move(sct), expectedEntry, time, result);
if (rv != Success) {
return rv;
}
}
return Success;
}
Result
MultiLogCTVerifier::VerifySingleSCT(SignedCertificateTimestamp&& sct,
const LogEntry& expectedEntry,
Time time,
CTVerifyResult& result)
{
CTLogVerifier* matchingLog = nullptr;
for (auto& log : mLogs) {
if (log.keyId() == sct.logId) {
matchingLog = &log;
break;
}
}
if (!matchingLog) {
// SCT does not match any known log.
return StoreVerifiedSct(result, Move(sct),
SignedCertificateTimestamp::VerificationStatus::UnknownLog);
}
if (!matchingLog->SignatureParametersMatch(sct.signature)) {
// SCT signature parameters do not match the log's.
return StoreVerifiedSct(result, Move(sct),
SignedCertificateTimestamp::VerificationStatus::InvalidSignature);
}
Result rv = matchingLog->Verify(expectedEntry, sct);
if (rv != Success) {
if (rv == Result::ERROR_BAD_SIGNATURE) {
return StoreVerifiedSct(result, Move(sct),
SignedCertificateTimestamp::VerificationStatus::InvalidSignature);
}
return rv;
}
// |sct.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
// is more "secure", although practically it does not matter.
Time sctTime = TimeFromEpochInSeconds((sct.timestamp + 999u) / 1000u);
// SCT verified ok, just make sure the timestamp is legitimate.
if (sctTime > time) {
return StoreVerifiedSct(result, Move(sct),
SignedCertificateTimestamp::VerificationStatus::InvalidTimestamp);
}
return StoreVerifiedSct(result, Move(sct),
SignedCertificateTimestamp::VerificationStatus::OK);
}
} } // namespace mozilla::ct
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