tls_client_target.cc

/* 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 <assert.h>
#include <stdint.h>
#include <memory>

#include "blapi.h"
#include "prinit.h"
#include "ssl.h"

#include "shared.h"
#include "tls_client_config.h"
#include "tls_common.h"
#include "tls_mutators.h"
#include "tls_socket.h"

#ifdef IS_DTLS
__attribute__((constructor)) static void set_is_dtls() {
  TlsMutators::SetIsDTLS();
}
#endif

PRFileDesc* ImportFD(PRFileDesc* model, PRFileDesc* fd) {
#ifdef IS_DTLS
  return DTLS_ImportFD(model, fd);
#else
  return SSL_ImportFD(model, fd);
#endif
}

static SECStatus AuthCertificateHook(void* arg, PRFileDesc* fd, PRBool checksig,
                                     PRBool isServer) {
  assert(!isServer);
  auto config = reinterpret_cast<ClientConfig*>(arg);
  return config->FailCertificateAuthentication() ? SECFailure : SECSuccess;
}

static void SetSocketOptions(PRFileDesc* fd,
                             std::unique_ptr<ClientConfig>& config) {
  SECStatus rv = SSL_OptionSet(fd, SSL_NO_CACHE, config->EnableCache());
  assert(rv == SECSuccess);

  rv = SSL_OptionSet(fd, SSL_ENABLE_EXTENDED_MASTER_SECRET,
                     config->EnableExtendedMasterSecret());
  assert(rv == SECSuccess);

  rv = SSL_OptionSet(fd, SSL_REQUIRE_DH_NAMED_GROUPS,
                     config->RequireDhNamedGroups());
  assert(rv == SECSuccess);

  rv = SSL_OptionSet(fd, SSL_ENABLE_FALSE_START, config->EnableFalseStart());
  assert(rv == SECSuccess);

  rv = SSL_OptionSet(fd, SSL_ENABLE_DEFLATE, config->EnableDeflate());
  assert(rv == SECSuccess);

  rv = SSL_OptionSet(fd, SSL_CBC_RANDOM_IV, config->EnableCbcRandomIv());
  assert(rv == SECSuccess);

  rv = SSL_OptionSet(fd, SSL_REQUIRE_SAFE_NEGOTIATION,
                     config->RequireSafeNegotiation());
  assert(rv == SECSuccess);

#ifndef IS_DTLS
  rv =
      SSL_OptionSet(fd, SSL_ENABLE_RENEGOTIATION, SSL_RENEGOTIATE_UNRESTRICTED);
  assert(rv == SECSuccess);
#endif
}

// This is only called when we set SSL_ENABLE_FALSE_START=1,
// so we can always just set *canFalseStart=true.
static SECStatus CanFalseStartCallback(PRFileDesc* fd, void* arg,
                                       PRBool* canFalseStart) {
  *canFalseStart = true;
  return SECSuccess;
}

static void SetupCallbacks(PRFileDesc* fd, ClientConfig* config) {
  SECStatus rv = SSL_AuthCertificateHook(fd, AuthCertificateHook, config);
  assert(rv == SECSuccess);

  rv = SSL_SetCanFalseStartCallback(fd, CanFalseStartCallback, nullptr);
  assert(rv == SECSuccess);
}

extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t len) {
  static std::unique_ptr<NSSDatabase> db(new NSSDatabase());
  assert(db != nullptr);

  EnableAllProtocolVersions();
  std::unique_ptr<ClientConfig> config(new ClientConfig(data, len));

  // Clear the cache. We never want to resume as we couldn't reproduce that.
  SSL_ClearSessionCache();

  // Reset the RNG state.
  assert(RNG_RandomUpdate(NULL, 0) == SECSuccess);

  // Create and import dummy socket.
  std::unique_ptr<DummyPrSocket> socket(new DummyPrSocket(data, len));
  static PRDescIdentity id = PR_GetUniqueIdentity("fuzz-client");
  ScopedPRFileDesc fd(DummyIOLayerMethods::CreateFD(id, socket.get()));
  PRFileDesc* ssl_fd = ImportFD(nullptr, fd.get());
  assert(ssl_fd == fd.get());

  // Probably not too important for clients.
  SSL_SetURL(ssl_fd, "server");

  SetSocketOptions(ssl_fd, config);
  EnableAllCipherSuites(ssl_fd);
  SetupCallbacks(ssl_fd, config.get());
  DoHandshake(ssl_fd, false);

  return 0;
}

extern "C" size_t LLVMFuzzerCustomMutator(uint8_t* data, size_t size,
                                          size_t max_size, unsigned int seed) {
  using namespace TlsMutators;
  return CustomMutate({DropRecord, ShuffleRecords, DuplicateRecord,
                       TruncateRecord, FragmentRecord},
                      data, size, max_size, seed);
}

extern "C" size_t LLVMFuzzerCustomCrossOver(const uint8_t* data1, size_t size1,
                                            const uint8_t* data2, size_t size2,
                                            uint8_t* out, size_t max_out_size,
                                            unsigned int seed) {
  return TlsMutators::CrossOver(data1, size1, data2, size2, out, max_out_size,
                                seed);
}