credentials.h

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/*
 *
 * Copyright 2015 gRPC authors.
 *
 * 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.
 *
 */
 
#ifndef GRPCPP_SECURITY_CREDENTIALS_H
#define GRPCPP_SECURITY_CREDENTIALS_H
 
#include <map>
#include <memory>
#include <vector>
 
#include <grpc/grpc_security_constants.h>
#include <grpcpp/channel.h>
#include <grpcpp/impl/codegen/client_interceptor.h>
#include <grpcpp/impl/codegen/grpc_library.h>
#include <grpcpp/security/auth_context.h>
#include <grpcpp/security/tls_credentials_options.h>
#include <grpcpp/support/channel_arguments.h>
#include <grpcpp/support/status.h>
#include <grpcpp/support/string_ref.h>
 
struct grpc_call;
 
namespace grpc {
class CallCredentials;
class SecureCallCredentials;
class SecureChannelCredentials;
class ChannelCredentials;
 
std::shared_ptr<Channel> CreateCustomChannel(
    const grpc::string& target,
    const std::shared_ptr<grpc::ChannelCredentials>& creds,
    const grpc::ChannelArguments& args);
 
namespace experimental {
std::shared_ptr<grpc::Channel> CreateCustomChannelWithInterceptors(
    const grpc::string& target,
    const std::shared_ptr<grpc::ChannelCredentials>& creds,
    const grpc::ChannelArguments& args,
    std::vector<
        std::unique_ptr<grpc::experimental::ClientInterceptorFactoryInterface>>
        interceptor_creators);
 
GRPC_DEPRECATED(
    "Use grpc::XdsCredentials instead. The experimental version will be "
    "deleted after the 1.41 release.")
std::shared_ptr<ChannelCredentials> XdsCredentials(
    const std::shared_ptr<ChannelCredentials>& fallback_creds);
}  // namespace experimental
 
std::shared_ptr<ChannelCredentials> XdsCredentials(
    const std::shared_ptr<ChannelCredentials>& fallback_creds);
 
class ChannelCredentials : private grpc::GrpcLibraryCodegen {
 public:
  ChannelCredentials();
  ~ChannelCredentials() override;
 
 protected:
  friend std::shared_ptr<ChannelCredentials> CompositeChannelCredentials(
      const std::shared_ptr<ChannelCredentials>& channel_creds,
      const std::shared_ptr<CallCredentials>& call_creds);
 
  // TODO(yashykt): We need this friend declaration mainly for access to
  // AsSecureCredentials(). Once we are able to remove insecure builds from gRPC
  // (and also internal dependencies on the indirect method of creating a
  // channel through credentials), we would be able to remove this.
  friend std::shared_ptr<ChannelCredentials> grpc::XdsCredentials(
      const std::shared_ptr<ChannelCredentials>& fallback_creds);
 
  virtual SecureChannelCredentials* AsSecureCredentials() = 0;
 
 private:
  friend std::shared_ptr<grpc::Channel> CreateCustomChannel(
      const grpc::string& target,
      const std::shared_ptr<grpc::ChannelCredentials>& creds,
      const grpc::ChannelArguments& args);
 
  friend std::shared_ptr<grpc::Channel>
  grpc::experimental::CreateCustomChannelWithInterceptors(
      const grpc::string& target,
      const std::shared_ptr<grpc::ChannelCredentials>& creds,
      const grpc::ChannelArguments& args,
      std::vector<std::unique_ptr<
          grpc::experimental::ClientInterceptorFactoryInterface>>
          interceptor_creators);
 
  virtual std::shared_ptr<Channel> CreateChannelImpl(
      const grpc::string& target, const ChannelArguments& args) = 0;
 
  // This function should have been a pure virtual function, but it is
  // implemented as a virtual function so that it does not break API.
  virtual std::shared_ptr<Channel> CreateChannelWithInterceptors(
      const grpc::string& /*target*/, const ChannelArguments& /*args*/,
      std::vector<std::unique_ptr<
          grpc::experimental::ClientInterceptorFactoryInterface>>
      /*interceptor_creators*/) {
    return nullptr;
  }
 
  // TODO(yashkt): This is a hack that is needed since InsecureCredentials can
  // not use grpc_channel_credentials internally and should be removed after
  // insecure builds are removed from gRPC.
  virtual bool IsInsecure() const { return false; }
};
 
class CallCredentials : private grpc::GrpcLibraryCodegen {
 public:
  CallCredentials();
  ~CallCredentials() override;
 
  virtual bool ApplyToCall(grpc_call* call) = 0;
  virtual grpc::string DebugString() {
    return "CallCredentials did not provide a debug string";
  }
 
 protected:
  friend std::shared_ptr<ChannelCredentials> CompositeChannelCredentials(
      const std::shared_ptr<ChannelCredentials>& channel_creds,
      const std::shared_ptr<CallCredentials>& call_creds);
 
  friend std::shared_ptr<CallCredentials> CompositeCallCredentials(
      const std::shared_ptr<CallCredentials>& creds1,
      const std::shared_ptr<CallCredentials>& creds2);
 
  virtual SecureCallCredentials* AsSecureCredentials() = 0;
};
 
struct SslCredentialsOptions {
  grpc::string pem_root_certs;
 
  grpc::string pem_private_key;
 
  grpc::string pem_cert_chain;
};
 
// Factories for building different types of Credentials The functions may
// return empty shared_ptr when credentials cannot be created. If a
// Credentials pointer is returned, it can still be invalid when used to create
// a channel. A lame channel will be created then and all rpcs will fail on it.
 
std::shared_ptr<ChannelCredentials> GoogleDefaultCredentials();
 
std::shared_ptr<ChannelCredentials> SslCredentials(
    const SslCredentialsOptions& options);
 
std::shared_ptr<CallCredentials> GoogleComputeEngineCredentials();
 
constexpr long kMaxAuthTokenLifetimeSecs = 3600;
 
std::shared_ptr<CallCredentials> ServiceAccountJWTAccessCredentials(
    const grpc::string& json_key,
    long token_lifetime_seconds = kMaxAuthTokenLifetimeSecs);
 
std::shared_ptr<CallCredentials> GoogleRefreshTokenCredentials(
    const grpc::string& json_refresh_token);
 
std::shared_ptr<CallCredentials> AccessTokenCredentials(
    const grpc::string& access_token);
 
std::shared_ptr<CallCredentials> GoogleIAMCredentials(
    const grpc::string& authorization_token,
    const grpc::string& authority_selector);
 
std::shared_ptr<ChannelCredentials> CompositeChannelCredentials(
    const std::shared_ptr<ChannelCredentials>& channel_creds,
    const std::shared_ptr<CallCredentials>& call_creds);
 
std::shared_ptr<CallCredentials> CompositeCallCredentials(
    const std::shared_ptr<CallCredentials>& creds1,
    const std::shared_ptr<CallCredentials>& creds2);
 
std::shared_ptr<ChannelCredentials> InsecureChannelCredentials();
 
class MetadataCredentialsPlugin {
 public:
  virtual ~MetadataCredentialsPlugin() {}
 
  virtual bool IsBlocking() const { return true; }
 
  virtual const char* GetType() const { return ""; }
 
  virtual grpc::Status GetMetadata(
      grpc::string_ref service_url, grpc::string_ref method_name,
      const grpc::AuthContext& channel_auth_context,
      std::multimap<grpc::string, grpc::string>* metadata) = 0;
 
  virtual grpc::string DebugString() {
    return "MetadataCredentialsPlugin did not provide a debug string";
  }
};
 
std::shared_ptr<CallCredentials> MetadataCredentialsFromPlugin(
    std::unique_ptr<MetadataCredentialsPlugin> plugin);
 
std::shared_ptr<CallCredentials> ExternalAccountCredentials(
    const grpc::string& json_string, const std::vector<grpc::string>& scopes);
 
namespace experimental {
 
struct StsCredentialsOptions {
  grpc::string token_exchange_service_uri;  // Required.
  grpc::string resource;                    // Optional.
  grpc::string audience;                    // Optional.
  grpc::string scope;                       // Optional.
  grpc::string requested_token_type;        // Optional.
  grpc::string subject_token_path;          // Required.
  grpc::string subject_token_type;          // Required.
  grpc::string actor_token_path;            // Optional.
  grpc::string actor_token_type;            // Optional.
};
 
grpc::Status StsCredentialsOptionsFromJson(const std::string& json_string,
                                           StsCredentialsOptions* options);
 
grpc::Status StsCredentialsOptionsFromEnv(StsCredentialsOptions* options);
 
std::shared_ptr<CallCredentials> StsCredentials(
    const StsCredentialsOptions& options);
 
std::shared_ptr<CallCredentials> MetadataCredentialsFromPlugin(
    std::unique_ptr<MetadataCredentialsPlugin> plugin,
    grpc_security_level min_security_level);
 
struct AltsCredentialsOptions {
  std::vector<grpc::string> target_service_accounts;
};
 
std::shared_ptr<ChannelCredentials> AltsCredentials(
    const AltsCredentialsOptions& options);
 
std::shared_ptr<ChannelCredentials> LocalCredentials(
    grpc_local_connect_type type);
 
std::shared_ptr<ChannelCredentials> TlsCredentials(
    const TlsChannelCredentialsOptions& options);
 
}  // namespace experimental
}  // namespace grpc
 
#endif  // GRPCPP_SECURITY_CREDENTIALS_H