name : clpreauth_plugin.h /* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */ /* * Copyright (c) 2006 Red Hat, Inc. * Portions copyright (c) 2006, 2011 Massachusetts Institute of Technology * All Rights Reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * Neither the name of Red Hat, Inc., nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /* * Declarations for clpreauth plugin module implementors. * * The clpreauth interface has a single supported major version, which is * 1. Major version 1 has a current minor version of 2. clpreauth modules * should define a function named clpreauth_<modulename>_initvt, matching * the signature: * * krb5_error_code * clpreauth_modname_initvt(krb5_context context, int maj_ver, * int min_ver, krb5_plugin_vtable vtable); * The initvt function should: * * - Check that the supplied maj_ver number is supported by the module, or * return KRB5_PLUGIN_VER_NOTSUPP if it is not. * * - Cast the vtable pointer as appropriate for the interface and maj_ver: * maj_ver == 1: Cast to krb5_clpreauth_vtable * * - Initialize the methods of the vtable, stopping as appropriate for the * supplied min_ver. Optional methods may be left uninitialized. * * Memory for the vtable is allocated by the caller, not by the module. */ #ifndef KRB5_CLPREAUTH_PLUGIN_H #define KRB5_CLPREAUTH_PLUGIN_H #include <krb5/krb5.h> #include <krb5/plugin.h> /* clpreauth mechanism property flags */ /* Provides a real answer which we can send back to the KDC. The client * assumes that one real answer will be enough. */ #define PA_REAL 0x00000001 /* Doesn't provide a real answer, but must be given a chance to run before any * REAL mechanism callbacks. */ #define PA_INFO 0x00000002 /* Abstract type for a client request information handle. */ typedef struct krb5_clpreauth_rock_st *krb5_clpreauth_rock; /* Abstract types for module data and per-request module data. */ typedef struct krb5_clpreauth_moddata_st *krb5_clpreauth_moddata; typedef struct krb5_clpreauth_modreq_st *krb5_clpreauth_modreq; /* Before using a callback after version 1, modules must check the vers * field of the callback structure. */ typedef struct krb5_clpreauth_callbacks_st { int vers; /* * If an AS-REP has been received, return the enctype of the AS-REP * encrypted part. Otherwise return the enctype chosen from etype-info, or * the first requested enctype if no etype-info was received. */ krb5_enctype (*get_etype)(krb5_context context, krb5_clpreauth_rock rock); /* Get a pointer to the FAST armor key, or NULL if the client is not using * FAST. The returned pointer is an alias and should not be freed. */ krb5_keyblock *(*fast_armor)(krb5_context context, krb5_clpreauth_rock rock); /* * Get a pointer to the client-supplied reply key, possibly invoking the * prompter to ask for a password if this has not already been done. The * returned pointer is an alias and should not be freed. */ krb5_error_code (*get_as_key)(krb5_context context, krb5_clpreauth_rock rock, krb5_keyblock **keyblock); /* Replace the reply key to be used to decrypt the AS response. */ krb5_error_code (*set_as_key)(krb5_context context, krb5_clpreauth_rock rock, const krb5_keyblock *keyblock); /* End of version 1 clpreauth callbacks. */ /* * Get the current time for use in a preauth response. If * allow_unauth_time is true and the library has been configured to allow * it, the current time will be offset using unauthenticated timestamp * information received from the KDC in the preauth-required error, if one * has been received. Otherwise, the timestamp in a preauth-required error * will only be used if it is protected by a FAST channel. Only set * allow_unauth_time if using an unauthenticated time offset would not * create a security issue. */ krb5_error_code (*get_preauth_time)(krb5_context context, krb5_clpreauth_rock rock, krb5_boolean allow_unauth_time, krb5_timestamp *time_out, krb5_int32 *usec_out); /* Set a question to be answered by the responder and optionally provide * a challenge. */ krb5_error_code (*ask_responder_question)(krb5_context context, krb5_clpreauth_rock rock, const char *question, const char *challenge); /* Get an answer from the responder, or NULL if the question was * unanswered. */ const char *(*get_responder_answer)(krb5_context context, krb5_clpreauth_rock rock, const char *question); /* Indicate interest in the AS key through the responder interface. */ void (*need_as_key)(krb5_context context, krb5_clpreauth_rock rock); /* * Get a configuration/state item from an input ccache, which may allow it * to retrace the steps it took last time. The returned data string is an * alias and should not be freed. */ const char *(*get_cc_config)(krb5_context context, krb5_clpreauth_rock rock, const char *key); /* * Set a configuration/state item which will be recorded to an output * ccache, if the calling application supplied one. Both key and data * should be valid UTF-8 text. */ krb5_error_code (*set_cc_config)(krb5_context context, krb5_clpreauth_rock rock, const char *key, const char *data); /* End of version 2 clpreauth callbacks (added in 1.11). */ /* * Prevent further fallbacks to other preauth mechanisms if the KDC replies * with an error. (The module itself can still respond to errors with its * tryagain method, or continue after KDC_ERR_MORE_PREAUTH_DATA_REQUIRED * errors with its process method.) A module should invoke this callback * from the process method when it generates an authenticated request using * credentials; often this will be the first or only client message * generated by the mechanism. */ void (*disable_fallback)(krb5_context context, krb5_clpreauth_rock rock); /* End of version 3 clpreauth callbacks (added in 1.17). */ } *krb5_clpreauth_callbacks; /* * Optional: per-plugin initialization/cleanup. The init function is called by * libkrb5 when the plugin is loaded, and the fini function is called before * the plugin is unloaded. These may be called multiple times in case the * plugin is used in multiple contexts. The returned context lives the * lifetime of the krb5_context. */ typedef krb5_error_code (*krb5_clpreauth_init_fn)(krb5_context context, krb5_clpreauth_moddata *moddata_out); typedef void (*krb5_clpreauth_fini_fn)(krb5_context context, krb5_clpreauth_moddata moddata); /* * Optional (mandatory before MIT krb5 1.12): pa_type will be a member of the * vtable's pa_type_list. Return PA_REAL if pa_type is a real * preauthentication type or PA_INFO if it is an informational type. If this * function is not defined in 1.12 or later, all pa_type values advertised by * the module will be assumed to be real. */ typedef int (*krb5_clpreauth_get_flags_fn)(krb5_context context, krb5_preauthtype pa_type); /* * Optional: per-request initialization/cleanup. The request_init function is * called when beginning to process a get_init_creds request and the * request_fini function is called when processing of the request is complete. * This is optional. It may be called multiple times in the lifetime of a * krb5_context. */ typedef void (*krb5_clpreauth_request_init_fn)(krb5_context context, krb5_clpreauth_moddata moddata, krb5_clpreauth_modreq *modreq_out); typedef void (*krb5_clpreauth_request_fini_fn)(krb5_context context, krb5_clpreauth_moddata moddata, krb5_clpreauth_modreq modreq); /* * Optional: process server-supplied data in pa_data and set responder * questions. * * encoded_previous_request may be NULL if there has been no previous request * in the AS exchange. */ typedef krb5_error_code (*krb5_clpreauth_prep_questions_fn)(krb5_context context, krb5_clpreauth_moddata moddata, krb5_clpreauth_modreq modreq, krb5_get_init_creds_opt *opt, krb5_clpreauth_callbacks cb, krb5_clpreauth_rock rock, krb5_kdc_req *request, krb5_data *encoded_request_body, krb5_data *encoded_previous_request, krb5_pa_data *pa_data); /* * Mandatory: process server-supplied data in pa_data and return created data * in pa_data_out. Also called after the AS-REP is received if the AS-REP * includes preauthentication data of the associated type. * * as_key contains the client-supplied key if known, or an empty keyblock if * not. If it is empty, the module may use gak_fct to fill it in. * * encoded_previous_request may be NULL if there has been no previous request * in the AS exchange. */ typedef krb5_error_code (*krb5_clpreauth_process_fn)(krb5_context context, krb5_clpreauth_moddata moddata, krb5_clpreauth_modreq modreq, krb5_get_init_creds_opt *opt, krb5_clpreauth_callbacks cb, krb5_clpreauth_rock rock, krb5_kdc_req *request, krb5_data *encoded_request_body, krb5_data *encoded_previous_request, krb5_pa_data *pa_data, krb5_prompter_fct prompter, void *prompter_data, krb5_pa_data ***pa_data_out); /* * Optional: Attempt to use error and error_padata to try to recover from the * given error. To work with both FAST and non-FAST errors, an implementation * should generally consult error_padata rather than decoding error->e_data. * For non-FAST errors, it contains the e_data decoded as either pa-data or * typed-data. * * If this function is provided, and it returns 0 and stores data in * pa_data_out, then the client library will retransmit the request. */ typedef krb5_error_code (*krb5_clpreauth_tryagain_fn)(krb5_context context, krb5_clpreauth_moddata moddata, krb5_clpreauth_modreq modreq, krb5_get_init_creds_opt *opt, krb5_clpreauth_callbacks cb, krb5_clpreauth_rock rock, krb5_kdc_req *request, krb5_data *encoded_request_body, krb5_data *encoded_previous_request, krb5_preauthtype pa_type, krb5_error *error, krb5_pa_data **error_padata, krb5_prompter_fct prompter, void *prompter_data, krb5_pa_data ***pa_data_out); /* * Optional: receive krb5_get_init_creds_opt information. The attr and value * information supplied should be copied into moddata by the module if it * wishes to reference it after returning from this call. */ typedef krb5_error_code (*krb5_clpreauth_supply_gic_opts_fn)(krb5_context context, krb5_clpreauth_moddata moddata, krb5_get_init_creds_opt *opt, const char *attr, const char *value); typedef struct krb5_clpreauth_vtable_st { /* Mandatory: name of module. */ char *name; /* Mandatory: pointer to zero-terminated list of pa_types which this module * can provide services for. */ krb5_preauthtype *pa_type_list; /* Optional: pointer to zero-terminated list of enc_types which this module * claims to add support for. */ krb5_enctype *enctype_list; krb5_clpreauth_init_fn init; krb5_clpreauth_fini_fn fini; krb5_clpreauth_get_flags_fn flags; krb5_clpreauth_request_init_fn request_init; krb5_clpreauth_request_fini_fn request_fini; krb5_clpreauth_process_fn process; krb5_clpreauth_tryagain_fn tryagain; krb5_clpreauth_supply_gic_opts_fn gic_opts; /* Minor version 1 ends here. */ krb5_clpreauth_prep_questions_fn prep_questions; /* Minor version 2 ends here. */ } *krb5_clpreauth_vtable; /* * This function allows a clpreauth plugin to obtain preauth options. The * preauth_data returned from this function should be freed by calling * krb5_get_init_creds_opt_free_pa(). */ krb5_error_code KRB5_CALLCONV krb5_get_init_creds_opt_get_pa(krb5_context context, krb5_get_init_creds_opt *opt, int *num_preauth_data, krb5_gic_opt_pa_data **preauth_data); /* * This function frees the preauth_data that was returned by * krb5_get_init_creds_opt_get_pa(). */ void KRB5_CALLCONV krb5_get_init_creds_opt_free_pa(krb5_context context, int num_preauth_data, krb5_gic_opt_pa_data *preauth_data); #endif /* KRB5_CLPREAUTH_PLUGIN_H */