krb5_interface.h

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/* Copyright (c) 2023, 2024, Oracle and/or its affiliates.
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.
 
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   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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   You should have received a copy of the GNU General Public License
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   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
 
#ifndef _KRB5_INTERFACE_H_
#define _KRB5_INTERFACE_H_
 
#include <string>
 
#include <assert.h>
#include <krb5/krb5.h>
#include <my_sharedlib.h>
#include <profile.h>
 
#include "log_client.h"
 
namespace auth_ldap_sasl_client {
 
/**
  \defgroup Krb5FunctionTypes Types of Krb5 interface functions.
  @{
*/
using krb5_build_principal_type = krb5_error_code (*)(krb5_context context,
                                                      krb5_principal *princ,
                                                      unsigned int rlen,
                                                      const char *realm, ...);
using krb5_cc_close_type = krb5_error_code (*)(krb5_context context,
                                               krb5_ccache cache);
using krb5_cc_default_type = krb5_error_code (*)(krb5_context context,
                                                 krb5_ccache *ccache);
using krb5_cc_get_principal_type = krb5_error_code (*)(
    krb5_context context, krb5_ccache cache, krb5_principal *principal);
using krb5_cc_initialize_type = krb5_error_code (*)(krb5_context context,
                                                    krb5_ccache cache,
                                                    krb5_principal principal);
using krb5_cc_remove_cred_type = krb5_error_code (*)(krb5_context context,
                                                     krb5_ccache cache,
                                                     krb5_flags flags,
                                                     krb5_creds *creds);
using krb5_cc_retrieve_cred_type = krb5_error_code (*)(krb5_context context,
                                                       krb5_ccache cache,
                                                       krb5_flags flags,
                                                       krb5_creds *mcreds,
                                                       krb5_creds *creds);
using krb5_cc_store_cred_type = krb5_error_code (*)(krb5_context context,
                                                    krb5_ccache cache,
                                                    krb5_creds *creds);
using krb5_free_context_type = void (*)(krb5_context context);
using krb5_free_cred_contents_type = void (*)(krb5_context context,
                                              krb5_creds *val);
using krb5_free_default_realm_type = void (*)(krb5_context context,
                                              char *lrealm);
using krb5_free_error_message_type = void (*)(krb5_context ctx,
                                              const char *msg);
using krb5_free_principal_type = void (*)(krb5_context context,
                                          krb5_principal val);
using krb5_free_unparsed_name_type = void (*)(krb5_context context, char *val);
using krb5_get_default_realm_type = krb5_error_code (*)(krb5_context context,
                                                        char **lrealm);
using krb5_get_error_message_type = const char *(*)(krb5_context ctx,
                                                    krb5_error_code code);
using krb5_get_init_creds_opt_alloc_type =
    krb5_error_code (*)(krb5_context context, krb5_get_init_creds_opt **opt);
using krb5_get_init_creds_opt_free_type =
    void (*)(krb5_context context, krb5_get_init_creds_opt *opt);
using krb5_get_init_creds_password_type = krb5_error_code (*)(
    krb5_context context, krb5_creds *creds, krb5_principal client,
    const char *password, krb5_prompter_fct prompter, void *data,
    krb5_deltat start_time, const char *in_tkt_service,
    krb5_get_init_creds_opt *k5_gic_options);
using krb5_get_profile_type = krb5_error_code (*)(krb5_context context,
                                                  struct _profile_t **profile);
 
using krb5_init_context_type = krb5_error_code (*)(krb5_context *context);
using krb5_parse_name_type = krb5_error_code (*)(krb5_context context,
                                                 const char *name,
                                                 krb5_principal *principal_out);
using krb5_timeofday_type = krb5_error_code (*)(krb5_context context,
                                                krb5_timestamp *timeret);
using krb5_unparse_name_type = krb5_error_code (*)(
    krb5_context context, krb5_const_principal principal, char **name);
using krb5_verify_init_creds_type = krb5_error_code (*)(
    krb5_context context, krb5_creds *creds, krb5_principal server,
    krb5_keytab keytab, krb5_ccache *ccache,
    krb5_verify_init_creds_opt *options);
using profile_get_boolean_type = long (*)(profile_t profile, const char *name,
                                          const char *subname,
                                          const char *subsubname, int def_val,
                                          int *ret_default);
using profile_get_string_type = long (*)(profile_t profile, const char *name,
                                         const char *subname,
                                         const char *subsubname,
                                         const char *def_val,
                                         char **ret_string);
using profile_release_type = void (*)(profile_t profile);
using profile_release_string_type = void (*)(char *str);
/**@}*/
 
/**
 Shortcut macro defining getter of the interfacee function
*/
#define KRB5_INTERFACE_DECLARE_FUNCTION(FUNCTION) \
  auto FUNCTION() {                               \
    assert(FUNCTION##_ptr);                       \
    return FUNCTION##_ptr;                        \
  }
 
/**
 Shortcut macro defining pointer to the interfacee function
*/
#define KRB5_INTERFACE_DECLARE_FUNCTION_PTR(FUNCTION) \
  FUNCTION##_type FUNCTION##_ptr;
 
/**
  Class representing interface to KRB5 functions.
  The functions are located in a library or libraries that are loaded in
  runtime. The class provides easy and safe access to them.
*/
class Krb5_interface {
 public:
  /**
   Constructor.
   The constructor is trivial and the libraries are not loaded by it. This is
   done in initialize() to give chance the caller to check if succeeded.
  */
  Krb5_interface();
 
  /**
   Destructor.
   Closes the libraries.
  */
  ~Krb5_interface();
 
  /**
   Initialize the object by loading the libraries and setting pointers to the
   interface functions. It must be called before any interface functions are
   called.
 
   @retval true success
   @retval false failure
  */
  bool initialize();
 
  /**
   \defgroup Krb5Functions Getters of pointers to the interface functions.
   @{
  */
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_build_principal)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_cc_close)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_cc_default)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_cc_get_principal)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_cc_initialize)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_cc_remove_cred)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_cc_retrieve_cred)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_cc_store_cred)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_free_context)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_free_cred_contents)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_free_default_realm)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_free_error_message)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_free_principal)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_free_unparsed_name)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_get_default_realm)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_get_error_message)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_get_init_creds_opt_alloc)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_get_init_creds_opt_free)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_get_init_creds_password)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_get_profile)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_init_context)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_parse_name)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_timeofday)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_unparse_name)
  KRB5_INTERFACE_DECLARE_FUNCTION(krb5_verify_init_creds)
  KRB5_INTERFACE_DECLARE_FUNCTION(profile_get_boolean)
  KRB5_INTERFACE_DECLARE_FUNCTION(profile_get_string)
  KRB5_INTERFACE_DECLARE_FUNCTION(profile_release)
  KRB5_INTERFACE_DECLARE_FUNCTION(profile_release_string)
  /**@}*/
 
 private:
  /**
   Handle to the library providing krb5_* functions
  */
  void *krb5_lib_handle;
 
  /**
   Handle to the library providing profile_* functions
  */
  void *profile_lib_handle;
 
  /**
   \defgroup Krb5FunctionPointers Pointers to the interface functions.
   @{
  */
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_build_principal)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_cc_close)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_cc_default)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_cc_get_principal)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_cc_initialize)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_cc_remove_cred)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_cc_retrieve_cred)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_cc_store_cred)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_free_context)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_free_cred_contents)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_free_default_realm)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_free_error_message)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_free_principal)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_free_unparsed_name)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_get_default_realm)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_get_error_message)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_get_init_creds_opt_alloc)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_get_init_creds_opt_free)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_get_init_creds_password)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_get_profile)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_init_context)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_parse_name)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_timeofday)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_unparse_name)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(krb5_verify_init_creds)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(profile_get_boolean)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(profile_get_string)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(profile_release)
  KRB5_INTERFACE_DECLARE_FUNCTION_PTR(profile_release_string)
  /**@}*/
 
  /**
   Loads single library.
 
   @param name [in] path or name of the library
   @param handle [out] handle to the library
 
   @retval true success
   @retval false failure
  */
  bool load_lib(const char *name, void *&handle);
 
  /**
   Closes the libraries.
  */
  void close_libs();
 
  /**
   Get pointer to the interface function by its name.
 
   @tparam T type of the function
   @param lib_handle [in] handle to the library providing the function
   @param name [in] name of the function
   @param function [out] pointer to the function
 
   @retval true success
   @retval false failure
  */
  template <class T>
  bool get_function(void *lib_handle, const char *name, T &function) {
    function = reinterpret_cast<T>(dlsym(lib_handle, name));
    if (function == nullptr) {
      log_error("Failed to load function ", name, ".");
      return false;
    }
    log_dbg("Successfuly loaded function ", name, ".");
    return true;
  }
};
}  // namespace auth_ldap_sasl_client
#endif  //_KRB5_INTERFACE_H_