auth_unix.c revision 261046 
1/*	$NetBSD: auth_unix.c,v 1.18 2000/07/06 03:03:30 christos Exp $	*/
2
3/*-
4 * Copyright (c) 2009, Sun Microsystems, Inc.
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 are met:
9 * - Redistributions of source code must retain the above copyright notice,
10 *   this list of conditions and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright notice,
12 *   this list of conditions and the following disclaimer in the documentation
13 *   and/or other materials provided with the distribution.
14 * - Neither the name of Sun Microsystems, Inc. nor the names of its
15 *   contributors may be used to endorse or promote products derived
16 *   from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
19 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
22 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28 * POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#if defined(LIBC_SCCS) && !defined(lint)
32static char *sccsid2 = "@(#)auth_unix.c 1.19 87/08/11 Copyr 1984 Sun Micro";
33static char *sccsid = "@(#)auth_unix.c	2.2 88/08/01 4.0 RPCSRC";
34#endif
35#include <sys/cdefs.h>
36__FBSDID("$FreeBSD: stable/10/sys/rpc/auth_unix.c 261046 2014-01-22 23:45:27Z mav $");
37
38/*
39 * auth_unix.c, Implements UNIX style authentication parameters.
40 *
41 * Copyright (C) 1984, Sun Microsystems, Inc.
42 *
43 * The system is very weak.  The client uses no encryption for it's
44 * credentials and only sends null verifiers.  The server sends backs
45 * null verifiers or optionally a verifier that suggests a new short hand
46 * for the credentials.
47 *
48 */
49
50#include <sys/param.h>
51#include <sys/systm.h>
52#include <sys/hash.h>
53#include <sys/kernel.h>
54#include <sys/lock.h>
55#include <sys/malloc.h>
56#include <sys/pcpu.h>
57#include <sys/refcount.h>
58#include <sys/sx.h>
59#include <sys/ucred.h>
60
61#include <rpc/types.h>
62#include <rpc/xdr.h>
63#include <rpc/auth.h>
64#include <rpc/clnt.h>
65
66#include <rpc/rpc_com.h>
67
68/* auth_unix.c */
69static void authunix_nextverf (AUTH *);
70static bool_t authunix_marshal (AUTH *, uint32_t, XDR *, struct mbuf *);
71static bool_t authunix_validate (AUTH *, uint32_t, struct opaque_auth *,
72    struct mbuf **);
73static bool_t authunix_refresh (AUTH *, void *);
74static void authunix_destroy (AUTH *);
75static void marshal_new_auth (AUTH *);
76
77static struct auth_ops authunix_ops = {
78	.ah_nextverf =		authunix_nextverf,
79	.ah_marshal =		authunix_marshal,
80	.ah_validate =		authunix_validate,
81	.ah_refresh =		authunix_refresh,
82	.ah_destroy =		authunix_destroy,
83};
84
85/*
86 * This struct is pointed to by the ah_private field of an auth_handle.
87 */
88struct audata {
89	TAILQ_ENTRY(audata)	au_link;
90	TAILQ_ENTRY(audata)	au_alllink;
91	volatile u_int		au_refs;
92	struct xucred		au_xcred;
93	struct opaque_auth	au_origcred;	/* original credentials */
94	struct opaque_auth	au_shcred;	/* short hand cred */
95	u_long			au_shfaults;	/* short hand cache faults */
96	char			au_marshed[MAX_AUTH_BYTES];
97	u_int			au_mpos;	/* xdr pos at end of marshed */
98	AUTH			*au_auth;	/* link back to AUTH */
99};
100TAILQ_HEAD(audata_list, audata);
101#define	AUTH_PRIVATE(auth)	((struct audata *)auth->ah_private)
102
103#define AUTH_UNIX_HASH_SIZE	16
104#define AUTH_UNIX_MAX		256
105static struct audata_list auth_unix_cache[AUTH_UNIX_HASH_SIZE];
106static struct audata_list auth_unix_all;
107static struct sx auth_unix_lock;
108static int auth_unix_count;
109
110static void
111authunix_init(void *dummy)
112{
113	int i;
114
115	for (i = 0; i < AUTH_UNIX_HASH_SIZE; i++)
116		TAILQ_INIT(&auth_unix_cache[i]);
117	TAILQ_INIT(&auth_unix_all);
118	sx_init(&auth_unix_lock, "auth_unix_lock");
119}
120SYSINIT(authunix_init, SI_SUB_KMEM, SI_ORDER_ANY, authunix_init, NULL);
121
122/*
123 * Create a unix style authenticator.
124 * Returns an auth handle with the given stuff in it.
125 */
126AUTH *
127authunix_create(struct ucred *cred)
128{
129	uint32_t h, th;
130	struct xucred xcr;
131	char mymem[MAX_AUTH_BYTES];
132	XDR xdrs;
133	AUTH *auth;
134	struct audata *au, *tau;
135	struct timeval now;
136	uint32_t time;
137	int len;
138
139	if (auth_unix_count > AUTH_UNIX_MAX) {
140		while (auth_unix_count > AUTH_UNIX_MAX) {
141			sx_xlock(&auth_unix_lock);
142			tau = TAILQ_FIRST(&auth_unix_all);
143			th = HASHSTEP(HASHINIT, tau->au_xcred.cr_uid)
144				% AUTH_UNIX_HASH_SIZE;
145			TAILQ_REMOVE(&auth_unix_cache[th], tau, au_link);
146			TAILQ_REMOVE(&auth_unix_all, tau, au_alllink);
147			auth_unix_count--;
148			sx_xunlock(&auth_unix_lock);
149			AUTH_DESTROY(tau->au_auth);
150		}
151	}
152
153	/*
154	 * Hash the uid to see if we already have an AUTH with this cred.
155	 */
156	h = HASHSTEP(HASHINIT, cred->cr_uid) % AUTH_UNIX_HASH_SIZE;
157	cru2x(cred, &xcr);
158again:
159	sx_slock(&auth_unix_lock);
160	TAILQ_FOREACH(au, &auth_unix_cache[h], au_link) {
161		if (!memcmp(&xcr, &au->au_xcred, sizeof(xcr))) {
162			refcount_acquire(&au->au_refs);
163			if (sx_try_upgrade(&auth_unix_lock)) {
164				/*
165				 * Keep auth_unix_all LRU sorted.
166				 */
167				TAILQ_REMOVE(&auth_unix_all, au, au_alllink);
168				TAILQ_INSERT_TAIL(&auth_unix_all, au,
169				    au_alllink);
170				sx_xunlock(&auth_unix_lock);
171			} else {
172				sx_sunlock(&auth_unix_lock);
173			}
174			return (au->au_auth);
175		}
176	}
177
178	sx_sunlock(&auth_unix_lock);
179
180	/*
181	 * Allocate and set up auth handle
182	 */
183	au = NULL;
184	auth = mem_alloc(sizeof(*auth));
185	au = mem_alloc(sizeof(*au));
186	auth->ah_ops = &authunix_ops;
187	auth->ah_private = (caddr_t)au;
188	auth->ah_verf = au->au_shcred = _null_auth;
189	refcount_init(&au->au_refs, 1);
190	au->au_xcred = xcr;
191	au->au_shfaults = 0;
192	au->au_origcred.oa_base = NULL;
193	au->au_auth = auth;
194
195	getmicrotime(&now);
196	time = now.tv_sec;
197
198	/*
199	 * Serialize the parameters into origcred
200	 */
201	xdrmem_create(&xdrs, mymem, MAX_AUTH_BYTES, XDR_ENCODE);
202	cru2x(cred, &xcr);
203	if (! xdr_authunix_parms(&xdrs, &time, &xcr))
204		panic("authunix_create: failed to encode creds");
205	au->au_origcred.oa_length = len = XDR_GETPOS(&xdrs);
206	au->au_origcred.oa_flavor = AUTH_UNIX;
207	au->au_origcred.oa_base = mem_alloc((u_int) len);
208	memcpy(au->au_origcred.oa_base, mymem, (size_t)len);
209
210	/*
211	 * set auth handle to reflect new cred.
212	 */
213	auth->ah_cred = au->au_origcred;
214	marshal_new_auth(auth);
215
216	sx_xlock(&auth_unix_lock);
217	TAILQ_FOREACH(tau, &auth_unix_cache[h], au_link) {
218		if (!memcmp(&xcr, &tau->au_xcred, sizeof(xcr))) {
219			/*
220			 * We lost a race to create the AUTH that
221			 * matches this cred.
222			 */
223			sx_xunlock(&auth_unix_lock);
224			AUTH_DESTROY(auth);
225			goto again;
226		}
227	}
228
229	auth_unix_count++;
230	TAILQ_INSERT_TAIL(&auth_unix_cache[h], au, au_link);
231	TAILQ_INSERT_TAIL(&auth_unix_all, au, au_alllink);
232	refcount_acquire(&au->au_refs);	/* one for the cache, one for user */
233	sx_xunlock(&auth_unix_lock);
234
235	return (auth);
236}
237
238/*
239 * authunix operations
240 */
241
242/* ARGSUSED */
243static void
244authunix_nextverf(AUTH *auth)
245{
246	/* no action necessary */
247}
248
249static bool_t
250authunix_marshal(AUTH *auth, uint32_t xid, XDR *xdrs, struct mbuf *args)
251{
252	struct audata *au;
253
254	au = AUTH_PRIVATE(auth);
255	if (!XDR_PUTBYTES(xdrs, au->au_marshed, au->au_mpos))
256		return (FALSE);
257
258	xdrmbuf_append(xdrs, args);
259
260	return (TRUE);
261}
262
263static bool_t
264authunix_validate(AUTH *auth, uint32_t xid, struct opaque_auth *verf,
265    struct mbuf **mrepp)
266{
267	struct audata *au;
268	XDR txdrs;
269
270	if (!verf)
271		return (TRUE);
272
273	if (verf->oa_flavor == AUTH_SHORT) {
274		au = AUTH_PRIVATE(auth);
275		xdrmem_create(&txdrs, verf->oa_base, verf->oa_length,
276		    XDR_DECODE);
277
278		if (au->au_shcred.oa_base != NULL) {
279			mem_free(au->au_shcred.oa_base,
280			    au->au_shcred.oa_length);
281			au->au_shcred.oa_base = NULL;
282		}
283		if (xdr_opaque_auth(&txdrs, &au->au_shcred)) {
284			auth->ah_cred = au->au_shcred;
285		} else {
286			txdrs.x_op = XDR_FREE;
287			(void)xdr_opaque_auth(&txdrs, &au->au_shcred);
288			au->au_shcred.oa_base = NULL;
289			auth->ah_cred = au->au_origcred;
290		}
291		marshal_new_auth(auth);
292	}
293
294	return (TRUE);
295}
296
297static bool_t
298authunix_refresh(AUTH *auth, void *dummy)
299{
300	struct audata *au = AUTH_PRIVATE(auth);
301	struct xucred xcr;
302	uint32_t time;
303	struct timeval now;
304	XDR xdrs;
305	int stat;
306
307	if (auth->ah_cred.oa_base == au->au_origcred.oa_base) {
308		/* there is no hope.  Punt */
309		return (FALSE);
310	}
311	au->au_shfaults ++;
312
313	/* first deserialize the creds back into a struct ucred */
314	xdrmem_create(&xdrs, au->au_origcred.oa_base,
315	    au->au_origcred.oa_length, XDR_DECODE);
316	stat = xdr_authunix_parms(&xdrs, &time, &xcr);
317	if (! stat)
318		goto done;
319
320	/* update the time and serialize in place */
321	getmicrotime(&now);
322	time = now.tv_sec;
323	xdrs.x_op = XDR_ENCODE;
324	XDR_SETPOS(&xdrs, 0);
325
326	stat = xdr_authunix_parms(&xdrs, &time, &xcr);
327	if (! stat)
328		goto done;
329	auth->ah_cred = au->au_origcred;
330	marshal_new_auth(auth);
331done:
332	XDR_DESTROY(&xdrs);
333	return (stat);
334}
335
336static void
337authunix_destroy(AUTH *auth)
338{
339	struct audata *au;
340
341	au = AUTH_PRIVATE(auth);
342
343	if (!refcount_release(&au->au_refs))
344		return;
345
346	mem_free(au->au_origcred.oa_base, au->au_origcred.oa_length);
347
348	if (au->au_shcred.oa_base != NULL)
349		mem_free(au->au_shcred.oa_base, au->au_shcred.oa_length);
350
351	mem_free(auth->ah_private, sizeof(struct audata));
352
353	if (auth->ah_verf.oa_base != NULL)
354		mem_free(auth->ah_verf.oa_base, auth->ah_verf.oa_length);
355
356	mem_free(auth, sizeof(*auth));
357}
358
359/*
360 * Marshals (pre-serializes) an auth struct.
361 * sets private data, au_marshed and au_mpos
362 */
363static void
364marshal_new_auth(AUTH *auth)
365{
366	XDR	xdr_stream;
367	XDR	*xdrs = &xdr_stream;
368	struct audata *au;
369
370	au = AUTH_PRIVATE(auth);
371	xdrmem_create(xdrs, au->au_marshed, MAX_AUTH_BYTES, XDR_ENCODE);
372	if ((! xdr_opaque_auth(xdrs, &(auth->ah_cred))) ||
373	    (! xdr_opaque_auth(xdrs, &(auth->ah_verf))))
374		printf("auth_none.c - Fatal marshalling problem");
375	else
376		au->au_mpos = XDR_GETPOS(xdrs);
377	XDR_DESTROY(xdrs);
378}
379