cose/simple_cms_parser.h

// Copyright 2026 Google LLC
//
// 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
//
//    https://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.
//

#ifndef THIRD_PARTY_CREDENTIO_COSE_SIMPLE_CMS_PARSER_H_
#define THIRD_PARTY_CREDENTIO_COSE_SIMPLE_CMS_PARSER_H_

#include <memory>
#include <string>
#include <vector>

#include "absl/status/status.h"
#include "absl/status/statusor.h"
#include "absl/strings/string_view.h"
#include "crypto/algorithms.h"
#include "crypto/default/cms/cms_parser.h"
#include "openssl/stack.h"
#include "openssl/x509.h"
#include "tsp/cms_parser.h"
#include "tsp/parsed_timestamp_token.h"

namespace credentio {

// ParsedTimestampToken implementation backed by the SimpleCMS library
class SimpleParsedTimestampToken : public ParsedTimestampToken {
 public:
  static absl::StatusOr<std::unique_ptr<SimpleParsedTimestampToken>> Create(
      absl::string_view timestamp_token);

  // SimpleParsedTimestampToken is self-referential (cms_ contains pointers into
  // data_). Copying or moving this object would invalidate those pointers.
  SimpleParsedTimestampToken(const SimpleParsedTimestampToken&) = delete;
  SimpleParsedTimestampToken& operator=(const SimpleParsedTimestampToken&) =
      delete;

  ~SimpleParsedTimestampToken() override = default;

  absl::Status VerifySignature() const override;
  absl::StatusOr<HashAlgorithm> GetMessageImprintHashAlgorithm() const override;
  absl::StatusOr<std::vector<std::string>> GetCertificateChain() const override;
  absl::StatusOr<absl::string_view> GetSigningCertificateV2Bytes()
      const override;
  absl::StatusOr<absl::string_view> GetTstInfoBytes() const override;

 private:
  explicit SimpleParsedTimestampToken(absl::string_view data);
  absl::StatusOr<const credentio_cms::SignerInfo*> GetSingleSignerInfo() const;
  absl::StatusOr<X509*> GetSignerCert(
      const STACK_OF(X509) * certs,
      const credentio_cms::SignerInfo& signer_info) const;

  const std::string data_;
  credentio_cms::Content cms_;
};

// CmsParser implementation backed by the SimpleCMS library
// (//third_party/simple_cms).
class SimpleCmsParser : public CmsParser {
 public:
  absl::StatusOr<std::unique_ptr<ParsedTimestampToken>> ParseTimestampToken(
      absl::string_view timestamp_token) const override;
};

}  // namespace credentio

#endif  // THIRD_PARTY_CREDENTIO_COSE_SIMPLE_CMS_PARSER_H_