FreeBSD/Linux Kernel Cross Reference
sys/rpc/auth_unix.c
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)
33 static char *sccsid2 = "@(#)auth_unix.c 1.19 87/08/11 Copyr 1984 Sun Micro";
34 static char *sccsid = "@(#)auth_unix.c 2.2 88/08/01 4.0 RPCSRC";
35 #endif
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD: src/sys/rpc/auth_unix.c,v 1.6 2008/11/03 10:38:00 dfr Exp $");
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 */
70 static void authunix_nextverf (AUTH *);
71 static bool_t authunix_marshal (AUTH *, uint32_t, XDR *, struct mbuf *);
72 static bool_t authunix_validate (AUTH *, uint32_t, struct opaque_auth *,
73 struct mbuf **);
74 static bool_t authunix_refresh (AUTH *, void *);
75 static void authunix_destroy (AUTH *);
76 static void marshal_new_auth (AUTH *);
77
78 static 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 */
89 struct 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 };
101 TAILQ_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
106 static struct audata_list auth_unix_cache[AUTH_UNIX_HASH_SIZE];
107 static struct audata_list auth_unix_all;
108 static struct sx auth_unix_lock;
109 static int auth_unix_count;
110
111 static void
112 authunix_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 }
121 SYSINIT(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 */
127 AUTH *
128 authunix_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);
159 again:
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 */
244 static void
245 authunix_nextverf(AUTH *auth)
246 {
247 /* no action necessary */
248 }
249
250 static bool_t
251 authunix_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
264 static bool_t
265 authunix_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
298 static bool_t
299 authunix_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);
332 done:
333 XDR_DESTROY(&xdrs);
334 return (stat);
335 }
336
337 static void
338 authunix_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 */
364 static void
365 marshal_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
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