xref: /freebsd/crypto/heimdal/lib/gssapi/mech/gss_mo.c (revision 6a068746777241722b2b32c5d0bc443a2a64d80b)
1 /*
2  * Copyright (c) 2010 Kungliga Tekniska Högskolan
3  * (Royal Institute of Technology, Stockholm, Sweden).
4  * All rights reserved.
5  *
6  * Portions Copyright (c) 2010 Apple Inc. All rights reserved.
7  * Portions Copyright (c) 2010 PADL Software Pty Ltd. All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  *
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  *
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  *
20  * 3. Neither the name of the Institute nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 
37 #include "mech_locl.h"
38 
39 #include <crypto-headers.h>
40 
41 static int
get_option_def(int def,gss_const_OID mech,gss_mo_desc * mo,gss_buffer_t value)42 get_option_def(int def, gss_const_OID mech, gss_mo_desc *mo, gss_buffer_t value)
43 {
44     return def;
45 }
46 
47 int
_gss_mo_get_option_1(gss_const_OID mech,gss_mo_desc * mo,gss_buffer_t value)48 _gss_mo_get_option_1(gss_const_OID mech, gss_mo_desc *mo, gss_buffer_t value)
49 {
50     return get_option_def(1, mech, mo, value);
51 }
52 
53 int
_gss_mo_get_option_0(gss_const_OID mech,gss_mo_desc * mo,gss_buffer_t value)54 _gss_mo_get_option_0(gss_const_OID mech, gss_mo_desc *mo, gss_buffer_t value)
55 {
56     return get_option_def(0, mech, mo, value);
57 }
58 
59 int
_gss_mo_get_ctx_as_string(gss_const_OID mech,gss_mo_desc * mo,gss_buffer_t value)60 _gss_mo_get_ctx_as_string(gss_const_OID mech, gss_mo_desc *mo, gss_buffer_t value)
61 {
62     if (value) {
63 	value->value = strdup((char *)mo->ctx);
64 	if (value->value == NULL)
65 	    return GSS_S_FAILURE;
66 	value->length = strlen((char *)mo->ctx);
67     }
68     return GSS_S_COMPLETE;
69 }
70 
71 GSSAPI_LIB_FUNCTION int GSSAPI_LIB_CALL
gss_mo_set(gss_const_OID mech,gss_const_OID option,int enable,gss_buffer_t value)72 gss_mo_set(gss_const_OID mech, gss_const_OID option,
73 	   int enable, gss_buffer_t value)
74 {
75     gssapi_mech_interface m;
76     size_t n;
77 
78     if ((m = __gss_get_mechanism(mech)) == NULL)
79 	return GSS_S_BAD_MECH;
80 
81     for (n = 0; n < m->gm_mo_num; n++)
82 	if (gss_oid_equal(option, m->gm_mo[n].option) && m->gm_mo[n].set)
83 	    return m->gm_mo[n].set(mech, &m->gm_mo[n], enable, value);
84 
85     return GSS_S_UNAVAILABLE;
86 }
87 
88 GSSAPI_LIB_FUNCTION int GSSAPI_LIB_CALL
gss_mo_get(gss_const_OID mech,gss_const_OID option,gss_buffer_t value)89 gss_mo_get(gss_const_OID mech, gss_const_OID option, gss_buffer_t value)
90 {
91     gssapi_mech_interface m;
92     size_t n;
93 
94     _mg_buffer_zero(value);
95 
96     if ((m = __gss_get_mechanism(mech)) == NULL)
97 	return GSS_S_BAD_MECH;
98 
99     for (n = 0; n < m->gm_mo_num; n++)
100 	if (gss_oid_equal(option, m->gm_mo[n].option) && m->gm_mo[n].get)
101 	    return m->gm_mo[n].get(mech, &m->gm_mo[n], value);
102 
103     return GSS_S_UNAVAILABLE;
104 }
105 
106 static void
add_all_mo(gssapi_mech_interface m,gss_OID_set * options,OM_uint32 mask)107 add_all_mo(gssapi_mech_interface m, gss_OID_set *options, OM_uint32 mask)
108 {
109     OM_uint32 minor;
110     size_t n;
111 
112     for (n = 0; n < m->gm_mo_num; n++)
113 	if ((m->gm_mo[n].flags & mask) == mask)
114 	    gss_add_oid_set_member(&minor, m->gm_mo[n].option, options);
115 }
116 
117 GSSAPI_LIB_FUNCTION void GSSAPI_LIB_CALL
gss_mo_list(gss_const_OID mech,gss_OID_set * options)118 gss_mo_list(gss_const_OID mech, gss_OID_set *options)
119 {
120     gssapi_mech_interface m;
121     OM_uint32 major, minor;
122 
123     if (options == NULL)
124 	return;
125 
126     *options = GSS_C_NO_OID_SET;
127 
128     if ((m = __gss_get_mechanism(mech)) == NULL)
129 	return;
130 
131     major = gss_create_empty_oid_set(&minor, options);
132     if (major != GSS_S_COMPLETE)
133 	return;
134 
135     add_all_mo(m, options, 0);
136 }
137 
138 GSSAPI_LIB_FUNCTION OM_uint32 GSSAPI_LIB_CALL
gss_mo_name(gss_const_OID mech,gss_const_OID option,gss_buffer_t name)139 gss_mo_name(gss_const_OID mech, gss_const_OID option, gss_buffer_t name)
140 {
141     gssapi_mech_interface m;
142     size_t n;
143 
144     if (name == NULL)
145 	return GSS_S_BAD_NAME;
146 
147     if ((m = __gss_get_mechanism(mech)) == NULL)
148 	return GSS_S_BAD_MECH;
149 
150     for (n = 0; n < m->gm_mo_num; n++) {
151 	if (gss_oid_equal(option, m->gm_mo[n].option)) {
152 	    /*
153 	     * If there is no name, its because its a GSS_C_MA and
154 	     * there is already a table for that.
155 	     */
156 	    if (m->gm_mo[n].name) {
157 		name->value = strdup(m->gm_mo[n].name);
158 		if (name->value == NULL)
159 		    return GSS_S_BAD_NAME;
160 		name->length = strlen(m->gm_mo[n].name);
161 		return GSS_S_COMPLETE;
162 	    } else {
163 		OM_uint32 junk;
164 		return gss_display_mech_attr(&junk, option,
165 					     NULL, name, NULL);
166 	    }
167 	}
168     }
169     return GSS_S_BAD_NAME;
170 }
171 
172 /*
173  * Helper function to allow NULL name
174  */
175 
176 static OM_uint32
mo_value(const gss_const_OID mech,gss_const_OID option,gss_buffer_t name)177 mo_value(const gss_const_OID mech, gss_const_OID option, gss_buffer_t name)
178 {
179     if (name == NULL)
180 	return GSS_S_COMPLETE;
181 
182     return gss_mo_get(mech, option, name);
183 }
184 
185 /* code derived from draft-ietf-cat-sasl-gssapi-01 */
186 static char basis_32[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
187 
188 static OM_uint32
make_sasl_name(OM_uint32 * minor,const gss_OID mech,char sasl_name[16])189 make_sasl_name(OM_uint32 *minor, const gss_OID mech, char sasl_name[16])
190 {
191     EVP_MD_CTX *ctx;
192     char *p = sasl_name;
193     u_char hdr[2], hash[20], *h = hash;
194 
195     if (mech->length > 127)
196         return GSS_S_BAD_MECH;
197 
198     hdr[0] = 0x06;
199     hdr[1] = mech->length;
200 
201     ctx = EVP_MD_CTX_create();
202     EVP_DigestInit_ex(ctx, EVP_sha1(), NULL);
203     EVP_DigestUpdate(ctx, hdr, 2);
204     EVP_DigestUpdate(ctx, mech->elements, mech->length);
205     EVP_DigestFinal_ex(ctx, hash, NULL);
206 
207     memcpy(p, "GS2-", 4);
208     p += 4;
209 
210     *p++ = basis_32[(h[0] >> 3)];
211     *p++ = basis_32[((h[0] & 7) << 2) | (h[1] >> 6)];
212     *p++ = basis_32[(h[1] & 0x3f) >> 1];
213     *p++ = basis_32[((h[1] & 1) << 4) | (h[2] >> 4)];
214     *p++ = basis_32[((h[2] & 0xf) << 1) | (h[3] >> 7)];
215     *p++ = basis_32[(h[3] & 0x7f) >> 2];
216     *p++ = basis_32[((h[3] & 3) << 3) | (h[4] >> 5)];
217     *p++ = basis_32[(h[4] & 0x1f)];
218     *p++ = basis_32[(h[5] >> 3)];
219     *p++ = basis_32[((h[5] & 7) << 2) | (h[6] >> 6)];
220     *p++ = basis_32[(h[6] & 0x3f) >> 1];
221 
222     *p = '\0';
223 
224     return GSS_S_COMPLETE;
225 }
226 
227 /*
228  * gss_inquire_saslname_for_mech() wrapper that uses MIT SPI
229  */
230 static OM_uint32
inquire_saslname_for_mech_compat(OM_uint32 * minor,const gss_OID desired_mech,gss_buffer_t sasl_mech_name,gss_buffer_t mech_name,gss_buffer_t mech_description)231 inquire_saslname_for_mech_compat(OM_uint32 *minor,
232                                  const gss_OID desired_mech,
233                                  gss_buffer_t sasl_mech_name,
234                                  gss_buffer_t mech_name,
235                                  gss_buffer_t mech_description)
236 {
237     struct gss_mech_compat_desc_struct *gmc;
238     gssapi_mech_interface m;
239     OM_uint32 major;
240 
241     m = __gss_get_mechanism(desired_mech);
242     if (m == NULL)
243         return GSS_S_BAD_MECH;
244 
245     gmc = m->gm_compat;
246 
247     if (gmc != NULL && gmc->gmc_inquire_saslname_for_mech != NULL) {
248         major = gmc->gmc_inquire_saslname_for_mech(minor,
249                                                    desired_mech,
250                                                    sasl_mech_name,
251                                                    mech_name,
252                                                    mech_description);
253     } else {
254         major = GSS_S_UNAVAILABLE;
255     }
256 
257     return major;
258 }
259 
260 /**
261  * Returns different protocol names and description of the mechanism.
262  *
263  * @param minor_status minor status code
264  * @param desired_mech mech list query
265  * @param sasl_mech_name SASL GS2 protocol name
266  * @param mech_name gssapi protocol name
267  * @param mech_description description of gssapi mech
268  *
269  * @return returns GSS_S_COMPLETE or a error code.
270  *
271  * @ingroup gssapi
272  */
273 
274 GSSAPI_LIB_FUNCTION OM_uint32 GSSAPI_LIB_CALL
gss_inquire_saslname_for_mech(OM_uint32 * minor_status,const gss_OID desired_mech,gss_buffer_t sasl_mech_name,gss_buffer_t mech_name,gss_buffer_t mech_description)275 gss_inquire_saslname_for_mech(OM_uint32 *minor_status,
276 			      const gss_OID desired_mech,
277 			      gss_buffer_t sasl_mech_name,
278 			      gss_buffer_t mech_name,
279 			      gss_buffer_t mech_description)
280 {
281     OM_uint32 major;
282 
283     _mg_buffer_zero(sasl_mech_name);
284     _mg_buffer_zero(mech_name);
285     _mg_buffer_zero(mech_description);
286 
287     if (minor_status)
288 	*minor_status = 0;
289 
290     if (desired_mech == NULL)
291 	return GSS_S_BAD_MECH;
292 
293     major = mo_value(desired_mech, GSS_C_MA_SASL_MECH_NAME, sasl_mech_name);
294     if (major == GSS_S_COMPLETE) {
295         /* Native SPI */
296         major = mo_value(desired_mech, GSS_C_MA_MECH_NAME, mech_name);
297         if (GSS_ERROR(major))
298             return major;
299 
300         major = mo_value(desired_mech, GSS_C_MA_MECH_DESCRIPTION, mech_description);
301         if (GSS_ERROR(major))
302             return major;
303     }
304 
305     if (GSS_ERROR(major)) {
306         /* API-as-SPI compatibility */
307         major = inquire_saslname_for_mech_compat(minor_status,
308                                                  desired_mech,
309                                                  sasl_mech_name,
310                                                  mech_name,
311                                                  mech_description);
312     }
313 
314     if (GSS_ERROR(major)) {
315         /* Algorithmically dervied SASL mechanism name */
316         char buf[16];
317         gss_buffer_desc tmp = { sizeof(buf) - 1, buf };
318 
319         major = make_sasl_name(minor_status, desired_mech, buf);
320         if (GSS_ERROR(major))
321             return major;
322 
323         major = _gss_copy_buffer(minor_status, &tmp, sasl_mech_name);
324         if (GSS_ERROR(major))
325             return major;
326     }
327 
328     return major;
329 }
330 
331 /**
332  * Find a mech for a sasl name
333  *
334  * @param minor_status minor status code
335  * @param sasl_mech_name
336  * @param mech_type
337  *
338  * @return returns GSS_S_COMPLETE or an error code.
339  */
340 
341 GSSAPI_LIB_FUNCTION OM_uint32 GSSAPI_LIB_CALL
gss_inquire_mech_for_saslname(OM_uint32 * minor_status,const gss_buffer_t sasl_mech_name,gss_OID * mech_type)342 gss_inquire_mech_for_saslname(OM_uint32 *minor_status,
343 			      const gss_buffer_t sasl_mech_name,
344 			      gss_OID *mech_type)
345 {
346     struct _gss_mech_switch *m;
347     gss_buffer_desc name;
348     OM_uint32 major, junk;
349     char buf[16];
350 
351     _gss_load_mech();
352 
353     *mech_type = NULL;
354 
355     HEIM_SLIST_FOREACH(m, &_gss_mechs, gm_link) {
356         struct gss_mech_compat_desc_struct *gmc;
357 
358         /* Native SPI */
359         major = mo_value(&m->gm_mech_oid, GSS_C_MA_SASL_MECH_NAME, &name);
360         if (major == GSS_S_COMPLETE &&
361             name.length == sasl_mech_name->length &&
362             memcmp(name.value, sasl_mech_name->value, name.length) == 0) {
363                 gss_release_buffer(&junk, &name);
364                 *mech_type = &m->gm_mech_oid;
365                 return GSS_S_COMPLETE;
366 	}
367 	gss_release_buffer(&junk, &name);
368 
369         if (GSS_ERROR(major)) {
370             /* API-as-SPI compatibility */
371             gmc = m->gm_mech.gm_compat;
372             if (gmc && gmc->gmc_inquire_mech_for_saslname) {
373                 major = gmc->gmc_inquire_mech_for_saslname(minor_status,
374                                                            sasl_mech_name,
375                                                            mech_type);
376                 if (major == GSS_S_COMPLETE)
377                     return GSS_S_COMPLETE;
378             }
379         }
380 
381         if (GSS_ERROR(major)) {
382             /* Algorithmically dervied SASL mechanism name */
383             if (sasl_mech_name->length == 16 &&
384                 make_sasl_name(minor_status, &m->gm_mech_oid, buf) == GSS_S_COMPLETE &&
385                 memcmp(buf, sasl_mech_name->value, 16) == 0) {
386                     *mech_type = &m->gm_mech_oid;
387                     return GSS_S_COMPLETE;
388             }
389         }
390     }
391 
392     return GSS_S_BAD_MECH;
393 }
394 
395 /*
396  * Test mechanism against indicated attributes using both Heimdal and
397  * MIT SPIs.
398  */
399 static int
test_mech_attrs(gssapi_mech_interface mi,gss_const_OID_set mech_attrs,gss_const_OID_set against_attrs,int except)400 test_mech_attrs(gssapi_mech_interface mi,
401                 gss_const_OID_set mech_attrs,
402                 gss_const_OID_set against_attrs,
403                 int except)
404 {
405     size_t n, m;
406     int eq = 0;
407 
408     if (against_attrs == GSS_C_NO_OID_SET)
409         return 1;
410 
411     for (n = 0; n < against_attrs->count; n++) {
412         for (m = 0; m < mi->gm_mo_num; m++) {
413             eq = gss_oid_equal(mi->gm_mo[m].option,
414                                &against_attrs->elements[n]);
415             if (eq)
416                 break;
417         }
418         if (mech_attrs != GSS_C_NO_OID_SET) {
419             for (m = 0; m < mech_attrs->count; m++) {
420                 eq = gss_oid_equal(&mech_attrs->elements[m],
421                                    &against_attrs->elements[n]);
422                 if (eq)
423                     break;
424             }
425         }
426         if (!eq ^ except)
427             return 0;
428     }
429 
430     return 1;
431 }
432 
433 /**
434  * Return set of mechanism that fullfill the criteria
435  *
436  * @param minor_status minor status code
437  * @param desired_mech_attrs
438  * @param except_mech_attrs
439  * @param critical_mech_attrs
440  * @param mechs returned mechs, free with gss_release_oid_set().
441  *
442  * @return returns GSS_S_COMPLETE or an error code.
443  */
444 
445 GSSAPI_LIB_FUNCTION OM_uint32 GSSAPI_LIB_CALL
gss_indicate_mechs_by_attrs(OM_uint32 * minor_status,gss_const_OID_set desired_mech_attrs,gss_const_OID_set except_mech_attrs,gss_const_OID_set critical_mech_attrs,gss_OID_set * mechs)446 gss_indicate_mechs_by_attrs(OM_uint32 * minor_status,
447 			    gss_const_OID_set desired_mech_attrs,
448 			    gss_const_OID_set except_mech_attrs,
449 			    gss_const_OID_set critical_mech_attrs,
450 			    gss_OID_set *mechs)
451 {
452     struct _gss_mech_switch *ms;
453     gss_OID_set mech_attrs = GSS_C_NO_OID_SET;
454     gss_OID_set known_mech_attrs = GSS_C_NO_OID_SET;
455     OM_uint32 major;
456 
457     major = gss_create_empty_oid_set(minor_status, mechs);
458     if (GSS_ERROR(major))
459 	return major;
460 
461     _gss_load_mech();
462 
463     HEIM_SLIST_FOREACH(ms, &_gss_mechs, gm_link) {
464 	gssapi_mech_interface mi = &ms->gm_mech;
465         struct gss_mech_compat_desc_struct *gmc = mi->gm_compat;
466         OM_uint32 tmp;
467 
468         if (gmc && gmc->gmc_inquire_attrs_for_mech) {
469             major = gmc->gmc_inquire_attrs_for_mech(minor_status,
470                                                     &mi->gm_mech_oid,
471                                                     &mech_attrs,
472                                                     &known_mech_attrs);
473             if (GSS_ERROR(major))
474                 continue;
475         }
476 
477         /*
478          * Test mechanism supports all of desired_mech_attrs;
479          * none of except_mech_attrs;
480          * and knows of all critical_mech_attrs.
481          */
482         if (test_mech_attrs(mi, mech_attrs,       desired_mech_attrs,  0) &&
483             test_mech_attrs(mi, mech_attrs,       except_mech_attrs,   1) &&
484             test_mech_attrs(mi, known_mech_attrs, critical_mech_attrs, 0)) {
485             major = gss_add_oid_set_member(minor_status, &mi->gm_mech_oid, mechs);
486         }
487 
488         gss_release_oid_set(&tmp, &mech_attrs);
489         gss_release_oid_set(&tmp, &known_mech_attrs);
490 
491         if (GSS_ERROR(major))
492             break;
493     }
494 
495     return major;
496 }
497 
498 /**
499  * List support attributes for a mech and/or all mechanisms.
500  *
501  * @param minor_status minor status code
502  * @param mech given together with mech_attr will return the list of
503  *        attributes for mechanism, can optionally be GSS_C_NO_OID.
504  * @param mech_attr see mech parameter, can optionally be NULL,
505  *        release with gss_release_oid_set().
506  * @param known_mech_attrs all attributes for mechanisms supported,
507  *        release with gss_release_oid_set().
508  *
509  * @ingroup gssapi
510  */
511 
512 GSSAPI_LIB_FUNCTION OM_uint32 GSSAPI_LIB_CALL
gss_inquire_attrs_for_mech(OM_uint32 * minor_status,gss_const_OID mech,gss_OID_set * mech_attr,gss_OID_set * known_mech_attrs)513 gss_inquire_attrs_for_mech(OM_uint32 * minor_status,
514 			   gss_const_OID mech,
515 			   gss_OID_set *mech_attr,
516 			   gss_OID_set *known_mech_attrs)
517 {
518     OM_uint32 major, junk;
519 
520     if (known_mech_attrs)
521         *known_mech_attrs = GSS_C_NO_OID_SET;
522 
523     if (mech_attr && mech) {
524 	gssapi_mech_interface m;
525         struct gss_mech_compat_desc_struct *gmc;
526 
527 	if ((m = __gss_get_mechanism(mech)) == NULL) {
528 	    *minor_status = 0;
529 	    return GSS_S_BAD_MECH;
530 	}
531 
532         gmc = m->gm_compat;
533 
534         if (gmc && gmc->gmc_inquire_attrs_for_mech) {
535             major = gmc->gmc_inquire_attrs_for_mech(minor_status,
536                                                     mech,
537                                                     mech_attr,
538                                                     known_mech_attrs);
539         } else {
540 	    major = gss_create_empty_oid_set(minor_status, mech_attr);
541             if (major == GSS_S_COMPLETE)
542 	        add_all_mo(m, mech_attr, GSS_MO_MA);
543         }
544 	if (GSS_ERROR(major))
545 	    return major;
546     }
547 
548     if (known_mech_attrs) {
549 	struct _gss_mech_switch *m;
550 
551         if (*known_mech_attrs == GSS_C_NO_OID_SET) {
552 	    major = gss_create_empty_oid_set(minor_status, known_mech_attrs);
553 	    if (GSS_ERROR(major)) {
554 	        if (mech_attr)
555 		    gss_release_oid_set(&junk, mech_attr);
556 	        return major;
557 	    }
558         }
559 
560 	_gss_load_mech();
561 
562 	HEIM_SLIST_FOREACH(m, &_gss_mechs, gm_link)
563 	    add_all_mo(&m->gm_mech, known_mech_attrs, GSS_MO_MA);
564     }
565 
566 
567     return GSS_S_COMPLETE;
568 }
569 
570 /**
571  * Return names and descriptions of mech attributes
572  *
573  * @param minor_status minor status code
574  * @param mech_attr
575  * @param name
576  * @param short_desc
577  * @param long_desc
578  *
579  * @return returns GSS_S_COMPLETE or an error code.
580  */
581 
582 GSSAPI_LIB_FUNCTION OM_uint32 GSSAPI_LIB_CALL
gss_display_mech_attr(OM_uint32 * minor_status,gss_const_OID mech_attr,gss_buffer_t name,gss_buffer_t short_desc,gss_buffer_t long_desc)583 gss_display_mech_attr(OM_uint32 * minor_status,
584 		      gss_const_OID mech_attr,
585 		      gss_buffer_t name,
586 		      gss_buffer_t short_desc,
587 		      gss_buffer_t long_desc)
588 {
589     struct _gss_oid_name_table *ma = NULL;
590     OM_uint32 major;
591     size_t n;
592 
593     _mg_buffer_zero(name);
594     _mg_buffer_zero(short_desc);
595     _mg_buffer_zero(long_desc);
596 
597     if (minor_status)
598 	*minor_status = 0;
599 
600     for (n = 0; ma == NULL && _gss_ont_ma[n].oid; n++)
601 	if (gss_oid_equal(mech_attr, _gss_ont_ma[n].oid))
602 	    ma = &_gss_ont_ma[n];
603 
604     if (ma == NULL)
605 	return GSS_S_BAD_MECH_ATTR;
606 
607     if (name) {
608 	gss_buffer_desc bd;
609 	bd.value = rk_UNCONST(ma->name);
610 	bd.length = strlen(ma->name);
611 	major = _gss_copy_buffer(minor_status, &bd, name);
612 	if (major != GSS_S_COMPLETE)
613 	    return major;
614     }
615 
616     if (short_desc) {
617 	gss_buffer_desc bd;
618 	bd.value = rk_UNCONST(ma->short_desc);
619 	bd.length = strlen(ma->short_desc);
620 	major = _gss_copy_buffer(minor_status, &bd, short_desc);
621 	if (major != GSS_S_COMPLETE)
622 	    return major;
623     }
624 
625     if (long_desc) {
626 	gss_buffer_desc bd;
627 	bd.value = rk_UNCONST(ma->long_desc);
628 	bd.length = strlen(ma->long_desc);
629 	major = _gss_copy_buffer(minor_status, &bd, long_desc);
630 	if (major != GSS_S_COMPLETE)
631 	    return major;
632     }
633 
634     return GSS_S_COMPLETE;
635 }
636