1 files changed, 193 insertions, 0 deletions
diff --git a/security/certverifier/MultiLogCTVerifier.cpp b/security/certverifier/MultiLogCTVerifier.cpp
new file mode 100644
index 000000000..619649b9f
--- /dev/null
+++ b/security/certverifier/MultiLogCTVerifier.cpp
@@ -0,0 +1,193 @@
+/* -*- 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