projects/boringssl/fuzz_certs.cc

// Copyright 2020 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
////////////////////////////////////////////////////////////////////////////////

// This fuzz target fuzzes the same API as
// https://github.com/google/boringssl/blob/master/fuzz/cert.cc, but it employs
// libprotobuf-mutator for structure-aware fuzzing.

#include <openssl/err.h>
#include <openssl/mem.h>
#include <openssl/x509.h>
#include "asn1_pdu.pb.h"
#include "asn1_pdu_to_der.h"
#include "libprotobuf-mutator/src/libfuzzer/libfuzzer_macro.h"

DEFINE_PROTO_FUZZER(const asn1_pdu::PDU& asn1) {
  asn1_pdu::ASN1PDUToDER converter;
  std::vector<uint8_t> encoded = converter.PDUToDER(asn1);
  const uint8_t* buf = encoded.data();
  size_t len = encoded.size();

  X509* x509 = d2i_X509(NULL, &buf, len);
  if (x509 != NULL) {
    // Extract the public key.
    EVP_PKEY_free(X509_get_pubkey(x509));

    // Reserialize the structure.
    uint8_t* der = NULL;
    i2d_X509(x509, &der);
    OPENSSL_free(der);
  }
  X509_free(x509);
  ERR_clear_error();
}