1/*	$NetBSD: auth_unix.c,v 1.18 2000/07/06 03:03:30 christos Exp $	*/
2
3/*
4 * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
5 * unrestricted use provided that this legend is included on all tape
6 * media and as a part of the software program in whole or part.  Users
7 * may copy or modify Sun RPC without charge, but are not authorized
8 * to license or distribute it to anyone else except as part of a product or
9 * program developed by the user.
10 *
11 * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
12 * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
13 * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
14 *
15 * Sun RPC is provided with no support and without any obligation on the
16 * part of Sun Microsystems, Inc. to assist in its use, correction,
17 * modification or enhancement.
18 *
19 * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
20 * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
21 * OR ANY PART THEREOF.
22 *
23 * In no event will Sun Microsystems, Inc. be liable for any lost revenue
24 * or profits or other special, indirect and consequential damages, even if
25 * Sun has been advised of the possibility of such damages.
26 *
27 * Sun Microsystems, Inc.
28 * 2550 Garcia Avenue
29 * Mountain View, California  94043
30 */
31
32#if defined(LIBC_SCCS) && !defined(lint)
33static char *sccsid2 = "@(#)auth_unix.c 1.19 87/08/11 Copyr 1984 Sun Micro";
34static char *sccsid = "@(#)auth_unix.c	2.2 88/08/01 4.0 RPCSRC";
35#endif
36#include <sys/cdefs.h>
37__FBSDID("$FreeBSD$");
38
39/*
40 * auth_unix.c, Implements UNIX style authentication parameters.
41 *
42 * Copyright (C) 1984, Sun Microsystems, Inc.
43 *
44 * The system is very weak.  The client uses no encryption for it's
45 * credentials and only sends null verifiers.  The server sends backs
46 * null verifiers or optionally a verifier that suggests a new short hand
47 * for the credentials.
48 *
49 */
50
51#include <sys/param.h>
52#include <sys/systm.h>
53#include <sys/hash.h>
54#include <sys/kernel.h>
55#include <sys/lock.h>
56#include <sys/malloc.h>
57#include <sys/pcpu.h>
58#include <sys/refcount.h>
59#include <sys/sx.h>
60#include <sys/ucred.h>
61
62#include <rpc/types.h>
63#include <rpc/xdr.h>
64#include <rpc/auth.h>
65#include <rpc/clnt.h>
66
67#include <rpc/rpc_com.h>
68
69/* auth_unix.c */
70static void authunix_nextverf (AUTH *);
71static bool_t authunix_marshal (AUTH *, uint32_t, XDR *, struct mbuf *);
72static bool_t authunix_validate (AUTH *, uint32_t, struct opaque_auth *,
73    struct mbuf **);
74static bool_t authunix_refresh (AUTH *, void *);
75static void authunix_destroy (AUTH *);
76static void marshal_new_auth (AUTH *);
77
78static struct auth_ops authunix_ops = {
79	.ah_nextverf =		authunix_nextverf,
80	.ah_marshal =		authunix_marshal,
81	.ah_validate =		authunix_validate,
82	.ah_refresh =		authunix_refresh,
83	.ah_destroy =		authunix_destroy,
84};
85
86/*
87 * This struct is pointed to by the ah_private field of an auth_handle.
88 */
89struct audata {
90	TAILQ_ENTRY(audata)	au_link;
91	TAILQ_ENTRY(audata)	au_alllink;
92	volatile u_int		au_refs;
93	struct xucred		au_xcred;
94	struct opaque_auth	au_origcred;	/* original credentials */
95	struct opaque_auth	au_shcred;	/* short hand cred */
96	u_long			au_shfaults;	/* short hand cache faults */
97	char			au_marshed[MAX_AUTH_BYTES];
98	u_int			au_mpos;	/* xdr pos at end of marshed */
99	AUTH			*au_auth;	/* link back to AUTH */
100};
101TAILQ_HEAD(audata_list, audata);
102#define	AUTH_PRIVATE(auth)	((struct audata *)auth->ah_private)
103
104#define AUTH_UNIX_HASH_SIZE	16
105#define AUTH_UNIX_MAX		256
106static struct audata_list auth_unix_cache[AUTH_UNIX_HASH_SIZE];
107static struct audata_list auth_unix_all;
108static struct sx auth_unix_lock;
109static int auth_unix_count;
110
111static void
112authunix_init(void *dummy)
113{
114	int i;
115
116	for (i = 0; i < AUTH_UNIX_HASH_SIZE; i++)
117		TAILQ_INIT(&auth_unix_cache[i]);
118	TAILQ_INIT(&auth_unix_all);
119	sx_init(&auth_unix_lock, "auth_unix_lock");
120}
121SYSINIT(authunix_init, SI_SUB_KMEM, SI_ORDER_ANY, authunix_init, NULL);
122
123/*
124 * Create a unix style authenticator.
125 * Returns an auth handle with the given stuff in it.
126 */
127AUTH *
128authunix_create(struct ucred *cred)
129{
130	uint32_t h, th;
131	struct xucred xcr;
132	char mymem[MAX_AUTH_BYTES];
133	XDR xdrs;
134	AUTH *auth;
135	struct audata *au, *tau;
136	struct timeval now;
137	uint32_t time;
138	int len;
139
140	if (auth_unix_count > AUTH_UNIX_MAX) {
141		while (auth_unix_count > AUTH_UNIX_MAX) {
142			sx_xlock(&auth_unix_lock);
143			tau = TAILQ_FIRST(&auth_unix_all);
144			th = HASHSTEP(HASHINIT, tau->au_xcred.cr_uid)
145				% AUTH_UNIX_HASH_SIZE;
146			TAILQ_REMOVE(&auth_unix_cache[th], tau, au_link);
147			TAILQ_REMOVE(&auth_unix_all, tau, au_alllink);
148			auth_unix_count--;
149			sx_xunlock(&auth_unix_lock);
150			AUTH_DESTROY(tau->au_auth);
151		}
152	}
153
154	/*
155	 * Hash the uid to see if we already have an AUTH with this cred.
156	 */
157	h = HASHSTEP(HASHINIT, cred->cr_uid) % AUTH_UNIX_HASH_SIZE;
158	cru2x(cred, &xcr);
159again:
160	sx_slock(&auth_unix_lock);
161	TAILQ_FOREACH(au, &auth_unix_cache[h], au_link) {
162		if (!memcmp(&xcr, &au->au_xcred, sizeof(xcr))) {
163			refcount_acquire(&au->au_refs);
164			if (sx_try_upgrade(&auth_unix_lock)) {
165				/*
166				 * Keep auth_unix_all LRU sorted.
167				 */
168				TAILQ_REMOVE(&auth_unix_all, au, au_alllink);
169				TAILQ_INSERT_TAIL(&auth_unix_all, au,
170				    au_alllink);
171				sx_xunlock(&auth_unix_lock);
172			} else {
173				sx_sunlock(&auth_unix_lock);
174			}
175			return (au->au_auth);
176		}
177	}
178
179	sx_sunlock(&auth_unix_lock);
180
181	/*
182	 * Allocate and set up auth handle
183	 */
184	au = NULL;
185	auth = mem_alloc(sizeof(*auth));
186	au = mem_alloc(sizeof(*au));
187	auth->ah_ops = &authunix_ops;
188	auth->ah_private = (caddr_t)au;
189	auth->ah_verf = au->au_shcred = _null_auth;
190	refcount_init(&au->au_refs, 1);
191	au->au_xcred = xcr;
192	au->au_shfaults = 0;
193	au->au_origcred.oa_base = NULL;
194	au->au_auth = auth;
195
196	getmicrotime(&now);
197	time = now.tv_sec;
198
199	/*
200	 * Serialize the parameters into origcred
201	 */
202	xdrmem_create(&xdrs, mymem, MAX_AUTH_BYTES, XDR_ENCODE);
203	cru2x(cred, &xcr);
204	if (! xdr_authunix_parms(&xdrs, &time, &xcr))
205		panic("authunix_create: failed to encode creds");
206	au->au_origcred.oa_length = len = XDR_GETPOS(&xdrs);
207	au->au_origcred.oa_flavor = AUTH_UNIX;
208	au->au_origcred.oa_base = mem_alloc((u_int) len);
209	memcpy(au->au_origcred.oa_base, mymem, (size_t)len);
210
211	/*
212	 * set auth handle to reflect new cred.
213	 */
214	auth->ah_cred = au->au_origcred;
215	marshal_new_auth(auth);
216
217	sx_xlock(&auth_unix_lock);
218	TAILQ_FOREACH(tau, &auth_unix_cache[h], au_link) {
219		if (!memcmp(&xcr, &tau->au_xcred, sizeof(xcr))) {
220			/*
221			 * We lost a race to create the AUTH that
222			 * matches this cred.
223			 */
224			sx_xunlock(&auth_unix_lock);
225			AUTH_DESTROY(auth);
226			goto again;
227		}
228	}
229
230	auth_unix_count++;
231	TAILQ_INSERT_TAIL(&auth_unix_cache[h], au, au_link);
232	TAILQ_INSERT_TAIL(&auth_unix_all, au, au_alllink);
233	refcount_acquire(&au->au_refs);	/* one for the cache, one for user */
234	sx_xunlock(&auth_unix_lock);
235
236	return (auth);
237}
238
239/*
240 * authunix operations
241 */
242
243/* ARGSUSED */
244static void
245authunix_nextverf(AUTH *auth)
246{
247	/* no action necessary */
248}
249
250static bool_t
251authunix_marshal(AUTH *auth, uint32_t xid, XDR *xdrs, struct mbuf *args)
252{
253	struct audata *au;
254
255	au = AUTH_PRIVATE(auth);
256	if (!XDR_PUTBYTES(xdrs, au->au_marshed, au->au_mpos))
257		return (FALSE);
258
259	xdrmbuf_append(xdrs, args);
260
261	return (TRUE);
262}
263
264static bool_t
265authunix_validate(AUTH *auth, uint32_t xid, struct opaque_auth *verf,
266    struct mbuf **mrepp)
267{
268	struct audata *au;
269	XDR txdrs;
270
271	if (!verf)
272		return (TRUE);
273
274	if (verf->oa_flavor == AUTH_SHORT) {
275		au = AUTH_PRIVATE(auth);
276		xdrmem_create(&txdrs, verf->oa_base, verf->oa_length,
277		    XDR_DECODE);
278
279		if (au->au_shcred.oa_base != NULL) {
280			mem_free(au->au_shcred.oa_base,
281			    au->au_shcred.oa_length);
282			au->au_shcred.oa_base = NULL;
283		}
284		if (xdr_opaque_auth(&txdrs, &au->au_shcred)) {
285			auth->ah_cred = au->au_shcred;
286		} else {
287			txdrs.x_op = XDR_FREE;
288			(void)xdr_opaque_auth(&txdrs, &au->au_shcred);
289			au->au_shcred.oa_base = NULL;
290			auth->ah_cred = au->au_origcred;
291		}
292		marshal_new_auth(auth);
293	}
294
295	return (TRUE);
296}
297
298static bool_t
299authunix_refresh(AUTH *auth, void *dummy)
300{
301	struct audata *au = AUTH_PRIVATE(auth);
302	struct xucred xcr;
303	uint32_t time;
304	struct timeval now;
305	XDR xdrs;
306	int stat;
307
308	if (auth->ah_cred.oa_base == au->au_origcred.oa_base) {
309		/* there is no hope.  Punt */
310		return (FALSE);
311	}
312	au->au_shfaults ++;
313
314	/* first deserialize the creds back into a struct ucred */
315	xdrmem_create(&xdrs, au->au_origcred.oa_base,
316	    au->au_origcred.oa_length, XDR_DECODE);
317	stat = xdr_authunix_parms(&xdrs, &time, &xcr);
318	if (! stat)
319		goto done;
320
321	/* update the time and serialize in place */
322	getmicrotime(&now);
323	time = now.tv_sec;
324	xdrs.x_op = XDR_ENCODE;
325	XDR_SETPOS(&xdrs, 0);
326
327	stat = xdr_authunix_parms(&xdrs, &time, &xcr);
328	if (! stat)
329		goto done;
330	auth->ah_cred = au->au_origcred;
331	marshal_new_auth(auth);
332done:
333	XDR_DESTROY(&xdrs);
334	return (stat);
335}
336
337static void
338authunix_destroy(AUTH *auth)
339{
340	struct audata *au;
341
342	au = AUTH_PRIVATE(auth);
343
344	if (!refcount_release(&au->au_refs))
345		return;
346
347	mem_free(au->au_origcred.oa_base, au->au_origcred.oa_length);
348
349	if (au->au_shcred.oa_base != NULL)
350		mem_free(au->au_shcred.oa_base, au->au_shcred.oa_length);
351
352	mem_free(auth->ah_private, sizeof(struct audata));
353
354	if (auth->ah_verf.oa_base != NULL)
355		mem_free(auth->ah_verf.oa_base, auth->ah_verf.oa_length);
356
357	mem_free(auth, sizeof(*auth));
358}
359
360/*
361 * Marshals (pre-serializes) an auth struct.
362 * sets private data, au_marshed and au_mpos
363 */
364static void
365marshal_new_auth(AUTH *auth)
366{
367	XDR	xdr_stream;
368	XDR	*xdrs = &xdr_stream;
369	struct audata *au;
370
371	au = AUTH_PRIVATE(auth);
372	xdrmem_create(xdrs, au->au_marshed, MAX_AUTH_BYTES, XDR_ENCODE);
373	if ((! xdr_opaque_auth(xdrs, &(auth->ah_cred))) ||
374	    (! xdr_opaque_auth(xdrs, &(auth->ah_verf))))
375		printf("auth_none.c - Fatal marshalling problem");
376	else
377		au->au_mpos = XDR_GETPOS(xdrs);
378	XDR_DESTROY(xdrs);
379}
380