1 /*
2 * lib/gssapi/krb5/set_allowable_enctypes.c
3 *
4 * Copyright 2004 by the Massachusetts Institute of Technology.
5 * All Rights Reserved.
6 *
7 * Export of this software from the United States of America may
8 * require a specific license from the United States Government.
9 * It is the responsibility of any person or organization contemplating
10 * export to obtain such a license before exporting.
11 *
12 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
13 * distribute this software and its documentation for any purpose and
14 * without fee is hereby granted, provided that the above copyright
15 * notice appear in all copies and that both that copyright notice and
16 * this permission notice appear in supporting documentation, and that
17 * the name of M.I.T. not be used in advertising or publicity pertaining
18 * to distribution of the software without specific, written prior
19 * permission. Furthermore if you modify this software you must label
20 * your software as modified software and not distribute it in such a
21 * fashion that it might be confused with the original M.I.T. software.
22 * M.I.T. makes no representations about the suitability of
23 * this software for any purpose. It is provided "as is" without express
24 * or implied warranty.
25 *
26 * krb5_gss_set_allowable_enctypes()
27 */
28
29 /*
30 * gss_krb5_set_allowable_enctypes
31 *
32 * This function may be called by a context initiator after calling
33 * gss_acquire_cred(), but before calling gss_init_sec_context(),
34 * to restrict the set of enctypes which will be negotiated during
35 * context establishment to those in the provided array.
36 *
37 * 'cred_handle' must be a valid credential handle obtained via
38 * gss_acquire_cred(). It may not be GSS_C_NO_CREDENTIAL.
39 * gss_acquire_cred() may be called with GSS_C_NO_CREDENTIAL
40 * to get a handle to the default credential.
41 *
42 * The purpose of this function is to limit the keys that may
43 * be exported via gss_krb5_export_lucid_sec_context(); thus it
44 * should limit the enctypes of all keys that will be needed
45 * after the security context has been established.
46 * (i.e. context establishment may use a session key with a
47 * stronger enctype than in the provided array, however a
48 * subkey must be established within the enctype limits
49 * established by this function.)
50 *
51 */
52
53 #include "gssapiP_krb5.h"
54 #ifdef HAVE_STRING_H
55 #include <string.h>
56 #else
57 #include <strings.h>
58 #endif
59 #include "gssapi_krb5.h"
60
61 OM_uint32 KRB5_CALLCONV
gss_krb5int_set_allowable_enctypes(OM_uint32 * minor_status,gss_cred_id_t cred_handle,OM_uint32 num_ktypes,krb5_enctype * ktypes)62 gss_krb5int_set_allowable_enctypes(OM_uint32 *minor_status,
63 gss_cred_id_t cred_handle,
64 OM_uint32 num_ktypes,
65 krb5_enctype *ktypes)
66 {
67 int i;
68 krb5_enctype * new_ktypes;
69 OM_uint32 major_status;
70 krb5_gss_cred_id_t cred;
71 krb5_error_code kerr = 0;
72 OM_uint32 temp_status;
73
74 /* Assume a failure */
75 *minor_status = 0;
76 major_status = GSS_S_FAILURE;
77
78 /* verify and valildate cred handle */
79 if (cred_handle == GSS_C_NO_CREDENTIAL) {
80 kerr = KRB5_NOCREDS_SUPPLIED;
81 goto error_out;
82 }
83 major_status = krb5_gss_validate_cred(&temp_status, cred_handle);
84 if (GSS_ERROR(major_status)) {
85 kerr = temp_status;
86 goto error_out;
87 }
88 cred = (krb5_gss_cred_id_t) cred_handle;
89
90 if (ktypes) {
91 for (i = 0; i < num_ktypes && ktypes[i]; i++) {
92 if (!krb5_c_valid_enctype(ktypes[i])) {
93 kerr = KRB5_PROG_ETYPE_NOSUPP;
94 goto error_out;
95 }
96 }
97 } else {
98 kerr = k5_mutex_lock(&cred->lock);
99 if (kerr)
100 goto error_out;
101 if (cred->req_enctypes)
102 free(cred->req_enctypes);
103 cred->req_enctypes = NULL;
104 k5_mutex_unlock(&cred->lock);
105 return GSS_S_COMPLETE;
106 }
107
108 /* Copy the requested ktypes into the cred structure */
109 if ((new_ktypes = (krb5_enctype *)malloc(sizeof(krb5_enctype) * (i + 1)))) {
110 memcpy(new_ktypes, ktypes, sizeof(krb5_enctype) * i);
111 new_ktypes[i] = 0; /* "null-terminate" the list */
112 }
113 else {
114 kerr = ENOMEM;
115 goto error_out;
116 }
117 kerr = k5_mutex_lock(&cred->lock);
118 if (kerr) {
119 free(new_ktypes);
120 goto error_out;
121 }
122 if (cred->req_enctypes)
123 free(cred->req_enctypes);
124 cred->req_enctypes = new_ktypes;
125 k5_mutex_unlock(&cred->lock);
126
127 /* Success! */
128 return GSS_S_COMPLETE;
129
130 error_out:
131 *minor_status = kerr;
132 return(major_status);
133 }
134