1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
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
29#include <gssapi/gssapi.h>
30#include <ctype.h>
31#include <dlfcn.h>
32#include <errno.h>
33#include <stdio.h>
34#include <stdlib.h>
35#include <string.h>
36
37#include "mech_switch.h"
38#include "utils.h"
39
40#ifndef _PATH_GSS_MECH
41#define _PATH_GSS_MECH	"/etc/gss/mech"
42#endif
43
44struct _gss_mech_switch_list _gss_mechs =
45	SLIST_HEAD_INITIALIZER(_gss_mechs);
46gss_OID_set _gss_mech_oids;
47
48/*
49 * Convert a string containing an OID in 'dot' form
50 * (e.g. 1.2.840.113554.1.2.2) to a gss_OID.
51 */
52static int
53_gss_string_to_oid(const char* s, gss_OID oid)
54{
55	int			number_count, i, j;
56	int			byte_count;
57	const char		*p, *q;
58	char			*res;
59
60	oid->length = 0;
61	oid->elements = NULL;
62
63	/*
64	 * First figure out how many numbers in the oid, then
65	 * calculate the compiled oid size.
66	 */
67	number_count = 0;
68	for (p = s; p; p = q) {
69		q = strchr(p, '.');
70		if (q) q = q + 1;
71		number_count++;
72	}
73
74	/*
75	 * The first two numbers are in the first byte and each
76	 * subsequent number is encoded in a variable byte sequence.
77	 */
78	if (number_count < 2)
79		return (EINVAL);
80
81	/*
82	 * We do this in two passes. The first pass, we just figure
83	 * out the size. Second time around, we actually encode the
84	 * number.
85	 */
86	res = NULL;
87	for (i = 0; i < 2; i++) {
88		byte_count = 0;
89		for (p = s, j = 0; p; p = q, j++) {
90			unsigned int number = 0;
91
92			/*
93			 * Find the end of this number.
94			 */
95			q = strchr(p, '.');
96			if (q) q = q + 1;
97
98			/*
99			 * Read the number of of the string. Don't
100			 * bother with anything except base ten.
101			 */
102			while (*p && *p != '.') {
103				number = 10 * number + (*p - '0');
104				p++;
105			}
106
107			/*
108			 * Encode the number. The first two numbers
109			 * are packed into the first byte. Subsequent
110			 * numbers are encoded in bytes seven bits at
111			 * a time with the last byte having the high
112			 * bit set.
113			 */
114			if (j == 0) {
115				if (res)
116					*res = number * 40;
117			} else if (j == 1) {
118				if (res) {
119					*res += number;
120					res++;
121				}
122				byte_count++;
123			} else if (j >= 2) {
124				/*
125				 * The number is encoded in seven bit chunks.
126				 */
127				unsigned int t;
128				int bytes;
129
130				bytes = 0;
131				for (t = number; t; t >>= 7)
132					bytes++;
133				if (bytes == 0) bytes = 1;
134				while (bytes) {
135					if (res) {
136						int bit = 7*(bytes-1);
137
138						*res = (number >> bit) & 0x7f;
139						if (bytes != 1)
140							*res |= 0x80;
141						res++;
142					}
143					byte_count++;
144					bytes--;
145				}
146			}
147		}
148		if (!res) {
149			res = malloc(byte_count);
150			if (!res)
151				return (ENOMEM);
152			oid->length = byte_count;
153			oid->elements = res;
154		}
155	}
156
157	return (0);
158}
159
160
161#define SYM(name)						\
162do {								\
163	snprintf(buf, sizeof(buf), "%s_%s",			\
164	    m->gm_name_prefix, #name);				\
165	m->gm_ ## name = dlsym(so, buf);			\
166	if (!m->gm_ ## name) {					\
167		fprintf(stderr, "can't find symbol %s\n", buf);	\
168		goto bad;					\
169	}							\
170} while (0)
171
172#define OPTSYM(name)				\
173do {						\
174	snprintf(buf, sizeof(buf), "%s_%s",	\
175	    m->gm_name_prefix, #name);		\
176	m->gm_ ## name = dlsym(so, buf);	\
177} while (0)
178
179/*
180 * Load the mechanisms file (/etc/gss/mech).
181 */
182void
183_gss_load_mech(void)
184{
185	OM_uint32	major_status, minor_status;
186	FILE		*fp;
187	char		buf[256];
188	char		*p;
189	char		*name, *oid, *lib, *kobj;
190	struct _gss_mech_switch *m;
191	void		*so;
192	const char	*(*prefix_fn)(void);
193
194	if (SLIST_FIRST(&_gss_mechs))
195		return;
196
197	major_status = gss_create_empty_oid_set(&minor_status,
198	    &_gss_mech_oids);
199	if (major_status)
200		return;
201
202	fp = fopen(_PATH_GSS_MECH, "r");
203	if (!fp) {
204		perror(_PATH_GSS_MECH);
205		return;
206	}
207
208	while (fgets(buf, sizeof(buf), fp)) {
209		if (*buf == '#')
210			continue;
211		p = buf;
212		name = strsep(&p, "\t\n ");
213		if (p) while (isspace(*p)) p++;
214		oid = strsep(&p, "\t\n ");
215		if (p) while (isspace(*p)) p++;
216		lib = strsep(&p, "\t\n ");
217		if (p) while (isspace(*p)) p++;
218		kobj = strsep(&p, "\t\n ");
219		if (!name || !oid || !lib || !kobj)
220			continue;
221
222		so = dlopen(lib, RTLD_LOCAL);
223		if (!so) {
224			fprintf(stderr, "dlopen: %s\n", dlerror());
225			continue;
226		}
227
228		m = malloc(sizeof(struct _gss_mech_switch));
229		if (!m)
230			break;
231		m->gm_so = so;
232		if (_gss_string_to_oid(oid, &m->gm_mech_oid)) {
233			free(m);
234			continue;
235		}
236
237		prefix_fn = (const char *(*)(void))
238			dlsym(so, "_gss_name_prefix");
239		if (prefix_fn)
240			m->gm_name_prefix = prefix_fn();
241		else
242			m->gm_name_prefix = "gss";
243
244		major_status = gss_add_oid_set_member(&minor_status,
245		    &m->gm_mech_oid, &_gss_mech_oids);
246		if (major_status) {
247			free(m->gm_mech_oid.elements);
248			free(m);
249			continue;
250		}
251
252		SYM(acquire_cred);
253		SYM(release_cred);
254		SYM(init_sec_context);
255		SYM(accept_sec_context);
256		SYM(process_context_token);
257		SYM(delete_sec_context);
258		SYM(context_time);
259		SYM(get_mic);
260		SYM(verify_mic);
261		SYM(wrap);
262		SYM(unwrap);
263		SYM(display_status);
264		OPTSYM(indicate_mechs);
265		SYM(compare_name);
266		SYM(display_name);
267		SYM(import_name);
268		SYM(export_name);
269		SYM(release_name);
270		SYM(inquire_cred);
271		SYM(inquire_context);
272		SYM(wrap_size_limit);
273		SYM(add_cred);
274		SYM(inquire_cred_by_mech);
275		SYM(export_sec_context);
276		SYM(import_sec_context);
277		SYM(inquire_names_for_mech);
278		SYM(inquire_mechs_for_name);
279		SYM(canonicalize_name);
280		SYM(duplicate_name);
281		OPTSYM(inquire_sec_context_by_oid);
282		OPTSYM(inquire_cred_by_oid);
283		OPTSYM(set_sec_context_option);
284		OPTSYM(set_cred_option);
285		OPTSYM(pseudo_random);
286		OPTSYM(pname_to_uid);
287
288		SLIST_INSERT_HEAD(&_gss_mechs, m, gm_link);
289		continue;
290
291	bad:
292		free(m->gm_mech_oid.elements);
293		free(m);
294		dlclose(so);
295		continue;
296	}
297	fclose(fp);
298}
299
300struct _gss_mech_switch *
301_gss_find_mech_switch(gss_OID mech)
302{
303	struct _gss_mech_switch *m;
304
305	_gss_load_mech();
306	SLIST_FOREACH(m, &_gss_mechs, gm_link) {
307		if (gss_oid_equal(&m->gm_mech_oid, mech))
308			return m;
309	}
310	return (0);
311}
312