////////////////////////////////////////////////////////////////////////////////
// Copyright 2013 Google LLC.
//
// This software is licensed under the terms defined in the Widevine Master
// License Agreement. For a copy of this agreement, please contact
// widevine-licensing@google.com.
////////////////////////////////////////////////////////////////////////////////

#include "common/test_utils.h"

#include <stddef.h>
#include <memory>

#include "glog/logging.h"
#include "openssl/pem.h"
#include "openssl/rsa.h"
#include "openssl/sha.h"

namespace widevine {

util::Status GenerateRsaSignatureSha256Pkcs1(const std::string& pem_private_key,
                                             const std::string& message,
                                             std::string* signature) {
  CHECK(signature);
  if (pem_private_key.empty()) {
    return util::Status(util::error::INVALID_ARGUMENT, "Empty PEM private key");
  }
  if (message.empty()) {
    return util::Status(util::error::INVALID_ARGUMENT, "Empty message");
  }
  BIO* bio(NULL);
  bio = BIO_new_mem_buf(const_cast<char*>(pem_private_key.data()),
                        pem_private_key.size());
  if (bio == NULL) {
    return util::Status(util::error::INTERNAL, "BIO allocation failed");
  }
  util::Status status;
  RSA* key(NULL);
  std::unique_ptr<char[]> sig_buffer;
  unsigned int sig_size;
  unsigned char digest[SHA256_DIGEST_LENGTH];
  key = PEM_read_bio_RSAPrivateKey(bio, NULL, NULL, NULL);
  if (key == NULL) {
    status = util::Status(util::Status::canonical_space(),
                            util::error::INVALID_ARGUMENT,
                            "PEM RSA private key load failed");
    goto cleanup;
  }
  SHA256(reinterpret_cast<const unsigned char*>(message.data()), message.size(),
         digest);
  sig_size = RSA_size(key);
  sig_buffer.reset(new char[sig_size]);
  if (RSA_sign(NID_sha256, digest, sizeof(digest),
               reinterpret_cast<unsigned char*>(sig_buffer.get()), &sig_size,
               key) != 1) {
    status =
        util::Status(util::Status::canonical_space(), util::error::INTERNAL,
                       "RSA private encrypt failed");
    goto cleanup;
  }
  signature->assign(sig_buffer.get(), sig_size);

cleanup:
  if (key != NULL) {
    RSA_free(key);
  }
  if (bio != NULL) {
    BIO_free(bio);
  }
  return status;
}

}  // namespace widevine