xref: /freebsd/crypto/krb5/src/include/krb5/ccselect_plugin.h (revision 7f2fe78b9dd5f51c821d771b63d2e096f6fd49e9)
1 /* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
2 /*
3  * Copyright (C) 2011 by the Massachusetts Institute of Technology.
4  * All rights reserved.
5  *
6  * Export of this software from the United States of America may
7  *   require a specific license from the United States Government.
8  *   It is the responsibility of any person or organization contemplating
9  *   export to obtain such a license before exporting.
10  *
11  * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
12  * distribute this software and its documentation for any purpose and
13  * without fee is hereby granted, provided that the above copyright
14  * notice appear in all copies and that both that copyright notice and
15  * this permission notice appear in supporting documentation, and that
16  * the name of M.I.T. not be used in advertising or publicity pertaining
17  * to distribution of the software without specific, written prior
18  * permission.  Furthermore if you modify this software you must label
19  * your software as modified software and not distribute it in such a
20  * fashion that it might be confused with the original M.I.T. software.
21  * M.I.T. makes no representations about the suitability of
22  * this software for any purpose.  It is provided "as is" without express
23  * or implied warranty.
24  */
25 
26 /*
27  * Declarations for credential cache selection module implementors.
28  *
29  * The ccselect pluggable interface currently has only one supported major
30  * version, which is 1.  Major version 1 has a current minor version number of
31  * 1.
32  *
33  * Credential cache selection modules should define a function named
34  * ccselect_<modulename>_initvt, matching the signature:
35  *
36  *   krb5_error_code
37  *   ccselect_modname_initvt(krb5_context context, int maj_ver, int min_ver,
38  *                           krb5_plugin_vtable vtable);
39  *
40  * The initvt function should:
41  *
42  * - Check that the supplied maj_ver number is supported by the module, or
43  *   return KRB5_PLUGIN_VER_NOTSUPP if it is not.
44  *
45  * - Cast the vtable pointer as appropriate for maj_ver:
46  *     maj_ver == 1: Cast to krb5_ccselect_vtable
47  *
48  * - Initialize the methods of the vtable, stopping as appropriate for the
49  *   supplied min_ver.  Optional methods may be left uninitialized.
50  *
51  * Memory for the vtable is allocated by the caller, not by the module.
52  */
53 
54 #ifndef KRB5_CCSELECT_PLUGIN_H
55 #define KRB5_CCSELECT_PLUGIN_H
56 
57 #include <krb5/krb5.h>
58 #include <krb5/plugin.h>
59 
60 /* An abstract type for credential cache selection module data. */
61 typedef struct krb5_ccselect_moddata_st *krb5_ccselect_moddata;
62 
63 #define KRB5_CCSELECT_PRIORITY_AUTHORITATIVE 2
64 #define KRB5_CCSELECT_PRIORITY_HEURISTIC     1
65 
66 /*** Method type declarations ***/
67 
68 /*
69  * Mandatory: Initialize module data and set *priority_out to one of the
70  * KRB5_CCSELECT_PRIORITY constants above.  Authoritative modules will be
71  * consulted before heuristic ones.
72  */
73 typedef krb5_error_code
74 (*krb5_ccselect_init_fn)(krb5_context context, krb5_ccselect_moddata *data_out,
75                          int *priority_out);
76 
77 /*
78  * Mandatory: Select a cache based on a server principal.  Return 0 on success,
79  * with *cache_out set to the selected cache and *princ_out set to its default
80  * principal.  Return KRB5_PLUGIN_NO_HANDLE to defer to other modules.  Return
81  * KRB5_CC_NOTFOUND with *princ_out set if the client principal can be
82  * authoritatively determined but no cache exists for it.  Return other errors
83  * as appropriate.
84  */
85 typedef krb5_error_code
86 (*krb5_ccselect_choose_fn)(krb5_context context, krb5_ccselect_moddata data,
87                            krb5_principal server, krb5_ccache *cache_out,
88                            krb5_principal *princ_out);
89 
90 /* Optional: Release resources used by module data. */
91 typedef void
92 (*krb5_ccselect_fini_fn)(krb5_context context, krb5_ccselect_moddata data);
93 
94 /*** vtable declarations **/
95 
96 /* Credential cache selection plugin vtable for major version 1. */
97 typedef struct krb5_ccselect_vtable_st {
98     const char *name;           /* Mandatory: name of module. */
99     krb5_ccselect_init_fn init;
100     krb5_ccselect_choose_fn choose;
101     krb5_ccselect_fini_fn fini;
102     /* Minor version 1 ends here. */
103 } *krb5_ccselect_vtable;
104 
105 #endif /* KRB5_CCSELECT_PLUGIN_H */
106