1/*
2  rpcsec_gss_prot.c
3
4  Copyright (c) 2000 The Regents of the University of Michigan.
5  All rights reserved.
6
7  Copyright (c) 2000 Dug Song <dugsong@UMICH.EDU>.
8  All rights reserved, all wrongs reversed.
9
10  Redistribution and use in source and binary forms, with or without
11  modification, are permitted provided that the following conditions
12  are met:
13
14  1. Redistributions of source code must retain the above copyright
15     notice, this list of conditions and the following disclaimer.
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  3. Neither the name of the University nor the names of its
20     contributors may be used to endorse or promote products derived
21     from this software without specific prior written permission.
22
23  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
24  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
25  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
26  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
28  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
29  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
30  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
31  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
32  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
33  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34
35  $Id: authgss_prot.c,v 1.18 2000/09/01 04:14:03 dugsong Exp $
36*/
37
38#include <sys/cdefs.h>
39__FBSDID("$FreeBSD$");
40
41#include <sys/param.h>
42#include <sys/systm.h>
43#include <sys/kobj.h>
44#include <sys/lock.h>
45#include <sys/malloc.h>
46#include <sys/mbuf.h>
47#include <sys/mutex.h>
48
49#include <rpc/rpc.h>
50#include <rpc/rpcsec_gss.h>
51
52#include "rpcsec_gss_int.h"
53
54#define MAX_GSS_SIZE	10240	/* XXX */
55
56#if 0				/* use the one from kgssapi */
57bool_t
58xdr_gss_buffer_desc(XDR *xdrs, gss_buffer_desc *p)
59{
60	char *val;
61	u_int len;
62	bool_t ret;
63
64	val = p->value;
65	len = p->length;
66	ret = xdr_bytes(xdrs, &val, &len, MAX_GSS_SIZE);
67	p->value = val;
68	p->length = len;
69
70	return (ret);
71}
72#endif
73
74bool_t
75xdr_rpc_gss_cred(XDR *xdrs, struct rpc_gss_cred *p)
76{
77	enum_t proc, svc;
78	bool_t ret;
79
80	proc = p->gc_proc;
81	svc = p->gc_svc;
82	ret = (xdr_u_int(xdrs, &p->gc_version) &&
83	    xdr_enum(xdrs, &proc) &&
84	    xdr_u_int(xdrs, &p->gc_seq) &&
85	    xdr_enum(xdrs, &svc) &&
86	    xdr_gss_buffer_desc(xdrs, &p->gc_handle));
87	p->gc_proc = proc;
88	p->gc_svc = svc;
89
90	return (ret);
91}
92
93bool_t
94xdr_rpc_gss_init_res(XDR *xdrs, struct rpc_gss_init_res *p)
95{
96
97	return (xdr_gss_buffer_desc(xdrs, &p->gr_handle) &&
98	    xdr_u_int(xdrs, &p->gr_major) &&
99	    xdr_u_int(xdrs, &p->gr_minor) &&
100	    xdr_u_int(xdrs, &p->gr_win) &&
101	    xdr_gss_buffer_desc(xdrs, &p->gr_token));
102}
103
104static void
105put_uint32(struct mbuf **mp, uint32_t v)
106{
107	struct mbuf *m = *mp;
108	uint32_t n;
109
110	M_PREPEND(m, sizeof(uint32_t), M_WAITOK);
111	n = htonl(v);
112	bcopy(&n, mtod(m, uint32_t *), sizeof(uint32_t));
113	*mp = m;
114}
115
116bool_t
117xdr_rpc_gss_wrap_data(struct mbuf **argsp,
118		      gss_ctx_id_t ctx, gss_qop_t qop,
119		      rpc_gss_service_t svc, u_int seq)
120{
121	struct mbuf	*args, *mic;
122	OM_uint32	maj_stat, min_stat;
123	int		conf_state;
124	u_int		len;
125	static char	zpad[4];
126
127	args = *argsp;
128
129	/*
130	 * Prepend the sequence number before calling gss_get_mic or gss_wrap.
131	 */
132	put_uint32(&args, seq);
133	len = m_length(args, NULL);
134
135	if (svc == rpc_gss_svc_integrity) {
136		/* Checksum rpc_gss_data_t. */
137		maj_stat = gss_get_mic_mbuf(&min_stat, ctx, qop, args, &mic);
138		if (maj_stat != GSS_S_COMPLETE) {
139			rpc_gss_log_debug("gss_get_mic failed");
140			m_freem(args);
141			return (FALSE);
142		}
143
144		/*
145		 * Marshal databody_integ. Note that since args is
146		 * already RPC encoded, there will be no padding.
147		 */
148		put_uint32(&args, len);
149
150		/*
151		 * Marshal checksum. This is likely to need padding.
152		 */
153		len = m_length(mic, NULL);
154		put_uint32(&mic, len);
155		if (len != RNDUP(len)) {
156			m_append(mic, RNDUP(len) - len, zpad);
157		}
158
159		/*
160		 * Concatenate databody_integ with checksum.
161		 */
162		m_cat(args, mic);
163	} else if (svc == rpc_gss_svc_privacy) {
164		/* Encrypt rpc_gss_data_t. */
165		maj_stat = gss_wrap_mbuf(&min_stat, ctx, TRUE, qop,
166		    &args, &conf_state);
167		if (maj_stat != GSS_S_COMPLETE) {
168			rpc_gss_log_status("gss_wrap", NULL,
169			    maj_stat, min_stat);
170			return (FALSE);
171		}
172
173		/*
174		 *  Marshal databody_priv and deal with RPC padding.
175		 */
176		len = m_length(args, NULL);
177		put_uint32(&args, len);
178		if (len != RNDUP(len)) {
179			m_append(args, RNDUP(len) - len, zpad);
180		}
181	}
182	*argsp = args;
183	return (TRUE);
184}
185
186static uint32_t
187get_uint32(struct mbuf **mp)
188{
189	struct mbuf *m = *mp;
190	uint32_t n;
191
192	if (m->m_len < sizeof(uint32_t)) {
193		m = m_pullup(m, sizeof(uint32_t));
194		if (!m) {
195			*mp = NULL;
196			return (0);
197		}
198	}
199	bcopy(mtod(m, uint32_t *), &n, sizeof(uint32_t));
200	m_adj(m, sizeof(uint32_t));
201	*mp = m;
202	return (ntohl(n));
203}
204
205static void
206m_trim(struct mbuf *m, int len)
207{
208	struct mbuf *n;
209	int off;
210
211	if (m == NULL)
212		return;
213	n = m_getptr(m, len, &off);
214	if (n) {
215		n->m_len = off;
216		if (n->m_next) {
217			m_freem(n->m_next);
218			n->m_next = NULL;
219		}
220	}
221}
222
223bool_t
224xdr_rpc_gss_unwrap_data(struct mbuf **resultsp,
225			gss_ctx_id_t ctx, gss_qop_t qop,
226			rpc_gss_service_t svc, u_int seq)
227{
228	struct mbuf	*results, *message, *mic;
229	uint32_t	len, cklen;
230	OM_uint32	maj_stat, min_stat;
231	u_int		seq_num, conf_state, qop_state;
232
233	results = *resultsp;
234	*resultsp = NULL;
235
236	message = NULL;
237	if (svc == rpc_gss_svc_integrity) {
238		/*
239		 * Extract the seq+message part. Remember that there
240		 * may be extra RPC padding in the checksum. The
241		 * message part is RPC encoded already so no
242		 * padding.
243		 */
244		len = get_uint32(&results);
245		message = results;
246		results = m_split(results, len, M_WAITOK);
247		if (!results) {
248			m_freem(message);
249			return (FALSE);
250		}
251
252		/*
253		 * Extract the MIC and make it contiguous.
254		 */
255		cklen = get_uint32(&results);
256		if (!results) {
257			m_freem(message);
258			return (FALSE);
259		}
260		KASSERT(cklen <= MHLEN, ("unexpected large GSS-API checksum"));
261		mic = results;
262		if (cklen > mic->m_len) {
263			mic = m_pullup(mic, cklen);
264			if (!mic) {
265				m_freem(message);
266				return (FALSE);
267			}
268		}
269		if (cklen != RNDUP(cklen))
270			m_trim(mic, cklen);
271
272		/* Verify checksum and QOP. */
273		maj_stat = gss_verify_mic_mbuf(&min_stat, ctx,
274		    message, mic, &qop_state);
275		m_freem(mic);
276
277		if (maj_stat != GSS_S_COMPLETE || qop_state != qop) {
278			m_freem(message);
279			rpc_gss_log_status("gss_verify_mic", NULL,
280			    maj_stat, min_stat);
281			return (FALSE);
282		}
283	} else if (svc == rpc_gss_svc_privacy) {
284		/* Decode databody_priv. */
285		len = get_uint32(&results);
286		if (!results)
287			return (FALSE);
288
289		/* Decrypt databody. */
290		message = results;
291		if (len != RNDUP(len))
292			m_trim(message, len);
293		maj_stat = gss_unwrap_mbuf(&min_stat, ctx, &message,
294		    &conf_state, &qop_state);
295
296		/* Verify encryption and QOP. */
297		if (maj_stat != GSS_S_COMPLETE) {
298			rpc_gss_log_status("gss_unwrap", NULL,
299			    maj_stat, min_stat);
300			return (FALSE);
301		}
302		if (qop_state != qop || conf_state != TRUE) {
303			m_freem(results);
304			return (FALSE);
305		}
306	}
307
308	/* Decode rpc_gss_data_t (sequence number + arguments). */
309	seq_num = get_uint32(&message);
310	if (!message)
311		return (FALSE);
312
313	/* Verify sequence number. */
314	if (seq_num != seq) {
315		rpc_gss_log_debug("wrong sequence number in databody");
316		m_freem(message);
317		return (FALSE);
318	}
319
320	*resultsp = message;
321	return (TRUE);
322}
323
324#ifdef DEBUG
325#include <machine/stdarg.h>
326
327void
328rpc_gss_log_debug(const char *fmt, ...)
329{
330	va_list ap;
331
332	va_start(ap, fmt);
333	printf("rpcsec_gss: ");
334	vprintf(fmt, ap);
335	printf("\n");
336	va_end(ap);
337}
338
339void
340rpc_gss_log_status(const char *m, gss_OID mech, OM_uint32 maj_stat, OM_uint32 min_stat)
341{
342	OM_uint32 min;
343	gss_buffer_desc msg;
344	int msg_ctx = 0;
345
346	printf("rpcsec_gss: %s: ", m);
347
348	gss_display_status(&min, maj_stat, GSS_C_GSS_CODE, GSS_C_NULL_OID,
349			   &msg_ctx, &msg);
350	printf("%s - ", (char *)msg.value);
351	gss_release_buffer(&min, &msg);
352
353	gss_display_status(&min, min_stat, GSS_C_MECH_CODE, mech,
354			   &msg_ctx, &msg);
355	printf("%s\n", (char *)msg.value);
356	gss_release_buffer(&min, &msg);
357}
358
359#else
360
361void
362rpc_gss_log_debug(__unused const char *fmt, ...)
363{
364}
365
366void
367rpc_gss_log_status(__unused const char *m, __unused gss_OID mech,
368    __unused OM_uint32 maj_stat, __unused OM_uint32 min_stat)
369{
370}
371
372#endif
373
374
375