gss_mech_switch.c revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2005 Doug Rabson
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 *	$FreeBSD: stable/11/lib/libgssapi/gss_mech_switch.c 330897 2018-03-14 03:19:51Z eadler $
29 */
30
31#include <gssapi/gssapi.h>
32#include <ctype.h>
33#include <dlfcn.h>
34#include <errno.h>
35#include <stdio.h>
36#include <stdlib.h>
37#include <string.h>
38
39#include "mech_switch.h"
40#include "utils.h"
41
42#ifndef _PATH_GSS_MECH
43#define _PATH_GSS_MECH	"/etc/gss/mech"
44#endif
45
46struct _gss_mech_switch_list _gss_mechs =
47	SLIST_HEAD_INITIALIZER(_gss_mechs);
48gss_OID_set _gss_mech_oids;
49
50/*
51 * Convert a string containing an OID in 'dot' form
52 * (e.g. 1.2.840.113554.1.2.2) to a gss_OID.
53 */
54static int
55_gss_string_to_oid(const char* s, gss_OID oid)
56{
57	int			number_count, i, j;
58	int			byte_count;
59	const char		*p, *q;
60	char			*res;
61
62	oid->length = 0;
63	oid->elements = NULL;
64
65	/*
66	 * First figure out how many numbers in the oid, then
67	 * calculate the compiled oid size.
68	 */
69	number_count = 0;
70	for (p = s; p; p = q) {
71		q = strchr(p, '.');
72		if (q) q = q + 1;
73		number_count++;
74	}
75
76	/*
77	 * The first two numbers are in the first byte and each
78	 * subsequent number is encoded in a variable byte sequence.
79	 */
80	if (number_count < 2)
81		return (EINVAL);
82
83	/*
84	 * We do this in two passes. The first pass, we just figure
85	 * out the size. Second time around, we actually encode the
86	 * number.
87	 */
88	res = NULL;
89	for (i = 0; i < 2; i++) {
90		byte_count = 0;
91		for (p = s, j = 0; p; p = q, j++) {
92			unsigned int number = 0;
93
94			/*
95			 * Find the end of this number.
96			 */
97			q = strchr(p, '.');
98			if (q) q = q + 1;
99
100			/*
101			 * Read the number of of the string. Don't
102			 * bother with anything except base ten.
103			 */
104			while (*p && *p != '.') {
105				number = 10 * number + (*p - '0');
106				p++;
107			}
108
109			/*
110			 * Encode the number. The first two numbers
111			 * are packed into the first byte. Subsequent
112			 * numbers are encoded in bytes seven bits at
113			 * a time with the last byte having the high
114			 * bit set.
115			 */
116			if (j == 0) {
117				if (res)
118					*res = number * 40;
119			} else if (j == 1) {
120				if (res) {
121					*res += number;
122					res++;
123				}
124				byte_count++;
125			} else if (j >= 2) {
126				/*
127				 * The number is encoded in seven bit chunks.
128				 */
129				unsigned int t;
130				int bytes;
131
132				bytes = 0;
133				for (t = number; t; t >>= 7)
134					bytes++;
135				if (bytes == 0) bytes = 1;
136				while (bytes) {
137					if (res) {
138						int bit = 7*(bytes-1);
139
140						*res = (number >> bit) & 0x7f;
141						if (bytes != 1)
142							*res |= 0x80;
143						res++;
144					}
145					byte_count++;
146					bytes--;
147				}
148			}
149		}
150		if (!res) {
151			res = malloc(byte_count);
152			if (!res)
153				return (ENOMEM);
154			oid->length = byte_count;
155			oid->elements = res;
156		}
157	}
158
159	return (0);
160}
161
162
163#define SYM(name)						\
164do {								\
165	snprintf(buf, sizeof(buf), "%s_%s",			\
166	    m->gm_name_prefix, #name);				\
167	m->gm_ ## name = dlsym(so, buf);			\
168	if (!m->gm_ ## name) {					\
169		fprintf(stderr, "can't find symbol %s\n", buf);	\
170		goto bad;					\
171	}							\
172} while (0)
173
174#define OPTSYM(name)				\
175do {						\
176	snprintf(buf, sizeof(buf), "%s_%s",	\
177	    m->gm_name_prefix, #name);		\
178	m->gm_ ## name = dlsym(so, buf);	\
179} while (0)
180
181/*
182 * Load the mechanisms file (/etc/gss/mech).
183 */
184void
185_gss_load_mech(void)
186{
187	OM_uint32	major_status, minor_status;
188	FILE		*fp;
189	char		buf[256];
190	char		*p;
191	char		*name, *oid, *lib, *kobj;
192	struct _gss_mech_switch *m;
193	int		count;
194	void		*so;
195	const char	*(*prefix_fn)(void);
196
197	if (SLIST_FIRST(&_gss_mechs))
198		return;
199
200	major_status = gss_create_empty_oid_set(&minor_status,
201	    &_gss_mech_oids);
202	if (major_status)
203		return;
204
205	fp = fopen(_PATH_GSS_MECH, "r");
206	if (!fp) {
207		perror(_PATH_GSS_MECH);
208		return;
209	}
210
211	count = 0;
212	while (fgets(buf, sizeof(buf), fp)) {
213		if (*buf == '#')
214			continue;
215		p = buf;
216		name = strsep(&p, "\t\n ");
217		if (p) while (isspace(*p)) p++;
218		oid = strsep(&p, "\t\n ");
219		if (p) while (isspace(*p)) p++;
220		lib = strsep(&p, "\t\n ");
221		if (p) while (isspace(*p)) p++;
222		kobj = strsep(&p, "\t\n ");
223		if (!name || !oid || !lib || !kobj)
224			continue;
225
226		so = dlopen(lib, RTLD_LOCAL);
227		if (!so) {
228			fprintf(stderr, "dlopen: %s\n", dlerror());
229			continue;
230		}
231
232		m = malloc(sizeof(struct _gss_mech_switch));
233		if (!m)
234			break;
235		m->gm_so = so;
236		if (_gss_string_to_oid(oid, &m->gm_mech_oid)) {
237			free(m);
238			continue;
239		}
240
241		prefix_fn = (const char *(*)(void))
242			dlsym(so, "_gss_name_prefix");
243		if (prefix_fn)
244			m->gm_name_prefix = prefix_fn();
245		else
246			m->gm_name_prefix = "gss";
247
248		major_status = gss_add_oid_set_member(&minor_status,
249		    &m->gm_mech_oid, &_gss_mech_oids);
250		if (major_status) {
251			free(m->gm_mech_oid.elements);
252			free(m);
253			continue;
254		}
255
256		SYM(acquire_cred);
257		SYM(release_cred);
258		SYM(init_sec_context);
259		SYM(accept_sec_context);
260		SYM(process_context_token);
261		SYM(delete_sec_context);
262		SYM(context_time);
263		SYM(get_mic);
264		SYM(verify_mic);
265		SYM(wrap);
266		SYM(unwrap);
267		SYM(display_status);
268		OPTSYM(indicate_mechs);
269		SYM(compare_name);
270		SYM(display_name);
271		SYM(import_name);
272		SYM(export_name);
273		SYM(release_name);
274		SYM(inquire_cred);
275		SYM(inquire_context);
276		SYM(wrap_size_limit);
277		SYM(add_cred);
278		SYM(inquire_cred_by_mech);
279		SYM(export_sec_context);
280		SYM(import_sec_context);
281		SYM(inquire_names_for_mech);
282		SYM(inquire_mechs_for_name);
283		SYM(canonicalize_name);
284		SYM(duplicate_name);
285		OPTSYM(inquire_sec_context_by_oid);
286		OPTSYM(inquire_cred_by_oid);
287		OPTSYM(set_sec_context_option);
288		OPTSYM(set_cred_option);
289		OPTSYM(pseudo_random);
290		OPTSYM(pname_to_uid);
291
292		SLIST_INSERT_HEAD(&_gss_mechs, m, gm_link);
293		count++;
294		continue;
295
296	bad:
297		free(m->gm_mech_oid.elements);
298		free(m);
299		dlclose(so);
300		continue;
301	}
302	fclose(fp);
303}
304
305struct _gss_mech_switch *
306_gss_find_mech_switch(gss_OID mech)
307{
308	struct _gss_mech_switch *m;
309
310	_gss_load_mech();
311	SLIST_FOREACH(m, &_gss_mechs, gm_link) {
312		if (gss_oid_equal(&m->gm_mech_oid, mech))
313			return m;
314	}
315	return (0);
316}
317