1/*
2 * Copyright (c) 2010, Oracle America, Inc.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are
6 * met:
7 *
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions and the following
12 * disclaimer in the documentation and/or other materials
13 * provided with the distribution.
14 * * Neither the name of the "Oracle America, 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
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
21 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
22 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
23 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
25 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
27 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
28 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 *
31 * svcauth_des.c, server-side des authentication
32 *
33 * We insure for the service the following:
34 * (1) The timestamp microseconds do not exceed 1 million.
35 * (2) The timestamp plus the window is less than the current time.
36 * (3) The timestamp is not less than the one previously
37 * seen in the current session.
38 *
39 * It is up to the server to determine if the window size is
40 * too small .
41 *
42 */
43
44#include <limits.h>
45#include <string.h>
46#include <stdint.h>
47#include <time.h>
48#include <sys/param.h>
49#include <netinet/in.h>
50#include <rpc/rpc.h>
51#include <rpc/xdr.h>
52#include <rpc/auth.h>
53#include <rpc/auth_des.h>
54#include <rpc/svc_auth.h>
55#include <rpc/svc.h>
56#include <rpc/des_crypt.h>
57#include <shlib-compat.h>
58
59#define debug(msg) /*printf("svcauth_des: %s\n", msg) */
60
61#define USEC_PER_SEC ((uint32_t) 1000000L)
62#define BEFORE(t1, t2) timercmp(t1, t2, <)
63
64/*
65 * LRU cache of conversation keys and some other useful items.
66 */
67#define AUTHDES_CACHESZ 64
68struct cache_entry
69 {
70 des_block key; /* conversation key */
71 char *rname; /* client's name */
72 u_int window; /* credential lifetime window */
73 struct rpc_timeval laststamp; /* detect replays of creds */
74 char *localcred; /* generic local credential */
75 };
76#define authdes_cache RPC_THREAD_VARIABLE(authdes_cache_s)
77#define authdes_lru RPC_THREAD_VARIABLE(authdes_lru_s)
78
79static void cache_init (void); /* initialize the cache */
80static short cache_spot (des_block *, char *, struct rpc_timeval *);
81 /* find an entry in the cache */
82static void cache_ref (uint32_t sid); /* note that sid was ref'd */
83
84static void invalidate (char *cred); /* invalidate entry in cache */
85
86/* Cache statistics. Accidental historic export without a matching
87 declaration in any header file. */
88#ifndef SHARED
89static
90#endif
91struct
92 {
93 u_long ncachehits; /* times cache hit, and is not replay */
94 u_long ncachereplays; /* times cache hit, and is replay */
95 u_long ncachemisses; /* times cache missed */
96 }
97svcauthdes_stats __attribute__ ((nocommon));
98#ifdef SHARED
99compat_symbol (libc, svcauthdes_stats, svcauthdes_stats, GLIBC_2_0);
100#endif
101
102/*
103 * Service side authenticator for AUTH_DES
104 */
105enum auth_stat
106_svcauth_des (register struct svc_req *rqst, register struct rpc_msg *msg)
107{
108 register uint32_t *ixdr;
109 des_block cryptbuf[2];
110 register struct authdes_cred *cred;
111 struct authdes_verf verf;
112 int status;
113 register struct cache_entry *entry;
114 uint32_t sid = 0;
115 des_block *sessionkey;
116 des_block ivec;
117 u_int window;
118 struct rpc_timeval timestamp;
119 uint32_t namelen;
120 struct area
121 {
122 struct authdes_cred area_cred;
123 char area_netname[MAXNETNAMELEN + 1];
124 }
125 *area;
126
127 if (authdes_cache == NULL)
128 cache_init ();
129 if (authdes_cache == NULL) /* No free memory */
130 return AUTH_FAILED;
131
132 area = (struct area *) rqst->rq_clntcred;
133 cred = (struct authdes_cred *) &area->area_cred;
134
135 /*
136 * Get the credential
137 */
138 if (msg->rm_call.cb_cred.oa_length <= 0 ||
139 msg->rm_call.cb_cred.oa_length > MAX_AUTH_BYTES)
140 return AUTH_BADCRED;
141
142 ixdr = (uint32_t *) msg->rm_call.cb_cred.oa_base;
143 cred->adc_namekind = IXDR_GET_ENUM (ixdr, enum authdes_namekind);
144 switch (cred->adc_namekind)
145 {
146 case ADN_FULLNAME:
147 namelen = IXDR_GET_U_INT32 (ixdr);
148 if (namelen > MAXNETNAMELEN)
149 {
150 return AUTH_BADCRED;
151 }
152 cred->adc_fullname.name = area->area_netname;
153 memcpy (cred->adc_fullname.name, (char *) ixdr, namelen);
154 cred->adc_fullname.name[namelen] = 0;
155 ixdr += (RNDUP (namelen) / BYTES_PER_XDR_UNIT);
156 cred->adc_fullname.key.key.high = *ixdr++;
157 cred->adc_fullname.key.key.low = *ixdr++;
158 cred->adc_fullname.window = *ixdr++;
159 break;
160 case ADN_NICKNAME:
161 cred->adc_nickname = *ixdr++;
162 break;
163 default:
164 return AUTH_BADCRED;
165 }
166
167 /*
168 * Get the verifier
169 */
170 if (msg->rm_call.cb_verf.oa_length <= 0 ||
171 msg->rm_call.cb_verf.oa_length > MAX_AUTH_BYTES)
172 return AUTH_BADCRED;
173
174 ixdr = (uint32_t *) msg->rm_call.cb_verf.oa_base;
175 verf.adv_xtimestamp.key.high = *ixdr++;
176 verf.adv_xtimestamp.key.low = *ixdr++;
177 verf.adv_int_u = *ixdr++;
178
179 /*
180 * Get the conversation key
181 */
182 if (cred->adc_namekind == ADN_FULLNAME)
183 {
184 netobj pkey;
185 char pkey_data[1024];
186
187 sessionkey = &cred->adc_fullname.key;
188 if (!getpublickey (cred->adc_fullname.name, pkey_data))
189 {
190 debug("getpublickey");
191 return AUTH_BADCRED;
192 }
193 pkey.n_bytes = pkey_data;
194 pkey.n_len = strlen (pkey_data) + 1;
195 if (key_decryptsession_pk (cred->adc_fullname.name, &pkey,
196 sessionkey) < 0)
197 {
198 debug ("decryptsessionkey");
199 return AUTH_BADCRED; /* key not found */
200 }
201 }
202 else
203 { /* ADN_NICKNAME */
204 if (cred->adc_nickname >= AUTHDES_CACHESZ)
205 {
206 debug ("bad nickname");
207 return AUTH_BADCRED; /* garbled credential */
208 }
209 else
210 sid = cred->adc_nickname;
211
212 /* XXX This could be wrong, but else we have a
213 security problem */
214 if (authdes_cache[sid].rname == NULL)
215 return AUTH_BADCRED;
216 sessionkey = &authdes_cache[sid].key;
217 }
218
219
220 /*
221 * Decrypt the timestamp
222 */
223 cryptbuf[0] = verf.adv_xtimestamp;
224 if (cred->adc_namekind == ADN_FULLNAME)
225 {
226 cryptbuf[1].key.high = cred->adc_fullname.window;
227 cryptbuf[1].key.low = verf.adv_winverf;
228 ivec.key.high = ivec.key.low = 0;
229 status = cbc_crypt ((char *) sessionkey, (char *) cryptbuf,
230 2 * sizeof (des_block), DES_DECRYPT | DES_HW,
231 (char *) &ivec);
232 }
233 else
234 status = ecb_crypt ((char *) sessionkey, (char *) cryptbuf,
235 sizeof (des_block), DES_DECRYPT | DES_HW);
236
237 if (DES_FAILED (status))
238 {
239 debug ("decryption failure");
240 return AUTH_FAILED; /* system error */
241 }
242
243 /*
244 * XDR the decrypted timestamp
245 */
246 ixdr = (uint32_t *) cryptbuf;
247 timestamp.tv_sec = IXDR_GET_INT32 (ixdr);
248 timestamp.tv_usec = IXDR_GET_INT32 (ixdr);
249
250 /*
251 * Check for valid credentials and verifiers.
252 * They could be invalid because the key was flushed
253 * out of the cache, and so a new session should begin.
254 * Be sure and send AUTH_REJECTED{CRED, VERF} if this is the case.
255 */
256 {
257 struct timeval current;
258 int nick;
259 u_int winverf;
260
261 if (cred->adc_namekind == ADN_FULLNAME)
262 {
263 short tmp_spot;
264
265 window = IXDR_GET_U_INT32 (ixdr);
266 winverf = IXDR_GET_U_INT32 (ixdr);
267 if (winverf != window - 1)
268 {
269 debug ("window verifier mismatch");
270 return AUTH_BADCRED; /* garbled credential */
271 }
272 tmp_spot = cache_spot (sessionkey, cred->adc_fullname.name,
273 &timestamp);
274 if (tmp_spot < 0 || tmp_spot > AUTHDES_CACHESZ)
275 {
276 debug ("replayed credential");
277 return AUTH_REJECTEDCRED; /* replay */
278 }
279 sid = tmp_spot;
280 nick = 0;
281 }
282 else
283 { /* ADN_NICKNAME */
284 window = authdes_cache[sid].window;
285 nick = 1;
286 }
287
288 if (timestamp.tv_usec >= USEC_PER_SEC)
289 {
290 debug ("invalid usecs");
291 /* cached out (bad key), or garbled verifier */
292 return nick ? AUTH_REJECTEDVERF : AUTH_BADVERF;
293 }
294 if (nick && BEFORE (&timestamp, &authdes_cache[sid].laststamp))
295 {
296 debug ("timestamp before last seen");
297 return AUTH_REJECTEDVERF; /* replay */
298 }
299 {
300 struct timespec now;
301 __clock_gettime (CLOCK_REALTIME, &now);
302 TIMESPEC_TO_TIMEVAL (&current, &now);
303 }
304 current.tv_sec -= window; /* allow for expiration */
305 if (!BEFORE (&current, &timestamp))
306 {
307 debug ("timestamp expired");
308 /* replay, or garbled credential */
309 return nick ? AUTH_REJECTEDVERF : AUTH_BADCRED;
310 }
311 }
312
313 /*
314 * Set up the reply verifier
315 */
316 verf.adv_nickname = sid;
317
318 /*
319 * xdr the timestamp before encrypting
320 */
321 ixdr = (uint32_t *) cryptbuf;
322 IXDR_PUT_INT32 (ixdr, timestamp.tv_sec - 1);
323 IXDR_PUT_INT32 (ixdr, timestamp.tv_usec);
324
325 /*
326 * encrypt the timestamp
327 */
328 status = ecb_crypt ((char *) sessionkey, (char *) cryptbuf,
329 sizeof (des_block), DES_ENCRYPT | DES_HW);
330 if (DES_FAILED (status))
331 {
332 debug ("encryption failure");
333 return AUTH_FAILED; /* system error */
334 }
335 verf.adv_xtimestamp = cryptbuf[0];
336
337 /*
338 * Serialize the reply verifier, and update rqst
339 */
340 ixdr = (uint32_t *) msg->rm_call.cb_verf.oa_base;
341 *ixdr++ = verf.adv_xtimestamp.key.high;
342 *ixdr++ = verf.adv_xtimestamp.key.low;
343 *ixdr++ = verf.adv_int_u;
344
345 rqst->rq_xprt->xp_verf.oa_flavor = AUTH_DES;
346 rqst->rq_xprt->xp_verf.oa_base = msg->rm_call.cb_verf.oa_base;
347 rqst->rq_xprt->xp_verf.oa_length =
348 (char *) ixdr - msg->rm_call.cb_verf.oa_base;
349
350 /*
351 * We succeeded, commit the data to the cache now and
352 * finish cooking the credential.
353 */
354 entry = &authdes_cache[sid];
355 entry->laststamp = timestamp;
356 cache_ref (sid);
357 if (cred->adc_namekind == ADN_FULLNAME)
358 {
359 size_t full_len;
360
361 cred->adc_fullname.window = window;
362 cred->adc_nickname = sid; /* save nickname */
363 if (entry->rname != NULL)
364 mem_free (entry->rname, strlen (entry->rname) + 1);
365 full_len = strlen (cred->adc_fullname.name) + 1;
366 entry->rname = mem_alloc ((u_int) full_len);
367 if (entry->rname != NULL)
368 memcpy (entry->rname, cred->adc_fullname.name, full_len);
369 else
370 {
371 debug ("out of memory");
372 return AUTH_FAILED; /* out of memory is bad */
373 }
374 entry->key = *sessionkey;
375 entry->window = window;
376 invalidate (entry->localcred); /* mark any cached cred invalid */
377 }
378 else
379 { /* ADN_NICKNAME */
380 /*
381 * nicknames are cooked into fullnames
382 */
383 cred->adc_namekind = ADN_FULLNAME;
384 cred->adc_fullname.name = entry->rname;
385 cred->adc_fullname.key = entry->key;
386 cred->adc_fullname.window = entry->window;
387 }
388 return AUTH_OK; /* we made it! */
389}
390
391
392/*
393 * Initialize the cache
394 */
395static void
396cache_init (void)
397{
398 register int i;
399
400 authdes_cache = (struct cache_entry *)
401 calloc (sizeof (struct cache_entry) * AUTHDES_CACHESZ, 1);
402 if (authdes_cache == NULL)
403 return;
404
405 authdes_lru = (int *) mem_alloc (sizeof (int) * AUTHDES_CACHESZ);
406 /*
407 * Initialize the lru list
408 */
409 for (i = 0; i < AUTHDES_CACHESZ; ++i)
410 authdes_lru[i] = i;
411}
412
413
414/*
415 * Find the lru victim
416 */
417static short
418cache_victim (void)
419{
420 return authdes_lru[AUTHDES_CACHESZ - 1];
421}
422
423/*
424 * Note that sid was referenced
425 */
426static void
427cache_ref (register uint32_t sid)
428{
429 register int i;
430 register int curr;
431 register int prev;
432
433 prev = authdes_lru[0];
434 authdes_lru[0] = sid;
435 for (i = 1; prev != sid; ++i)
436 {
437 curr = authdes_lru[i];
438 authdes_lru[i] = prev;
439 prev = curr;
440 }
441}
442
443/*
444 * Find a spot in the cache for a credential containing
445 * the items given. Return -1 if a replay is detected, otherwise
446 * return the spot in the cache.
447 */
448static short
449cache_spot (register des_block *key, char *name,
450 struct rpc_timeval *timestamp)
451{
452 register struct cache_entry *cp;
453 register int i;
454 register uint32_t hi;
455
456 hi = key->key.high;
457 for (cp = authdes_cache, i = 0; i < AUTHDES_CACHESZ; ++i, ++cp)
458 {
459 if (cp->key.key.high == hi &&
460 cp->key.key.low == key->key.low &&
461 cp->rname != NULL &&
462 memcmp (cp->rname, name, strlen (name) + 1) == 0)
463 {
464 if (BEFORE (timestamp, &cp->laststamp))
465 {
466 ++svcauthdes_stats.ncachereplays;
467 return -1; /* replay */
468 }
469 ++svcauthdes_stats.ncachehits;
470 return i; /* refresh */
471 }
472 }
473 ++svcauthdes_stats.ncachemisses;
474 return cache_victim (); /* new credential */
475}
476
477/*
478 * Local credential handling stuff.
479 * NOTE: bsd unix dependent.
480 * Other operating systems should put something else here.
481 */
482#define UNKNOWN -2 /* grouplen, if cached cred is unknown user */
483#define INVALID -1 /* grouplen, if cache entry is invalid */
484
485struct bsdcred
486{
487 uid_t uid; /* cached uid */
488 gid_t gid; /* cached gid */
489 int grouplen; /* length of cached groups */
490 int grouplen_max; /* length of allocated cached groups */
491 gid_t groups[0]; /* cached groups */
492};
493
494/*
495 * Map a des credential into a unix cred.
496 * We cache the credential here so the application does
497 * not have to make an rpc call every time to interpret
498 * the credential.
499 */
500int
501authdes_getucred (const struct authdes_cred *adc, uid_t * uid, gid_t * gid,
502 short *grouplen, gid_t * groups)
503{
504 unsigned sid;
505 register int i;
506 uid_t i_uid;
507 gid_t i_gid;
508 int i_grouplen;
509 struct bsdcred *cred;
510
511 sid = adc->adc_nickname;
512 if (sid >= AUTHDES_CACHESZ)
513 {
514 debug ("invalid nickname");
515 return 0;
516 }
517 cred = (struct bsdcred *) authdes_cache[sid].localcred;
518 if (cred == NULL || cred->grouplen == INVALID)
519 {
520 /*
521 * not in cache: lookup
522 */
523 if (!netname2user (adc->adc_fullname.name, &i_uid, &i_gid,
524 &i_grouplen, groups))
525 {
526 debug ("unknown netname");
527 if (cred != NULL)
528 cred->grouplen = UNKNOWN; /* mark as lookup up, but not found */
529 return 0;
530 }
531
532 if (cred != NULL && cred->grouplen_max < i_grouplen)
533 {
534 /* We already have an allocated data structure. But it is
535 too small. */
536 free (cred);
537 authdes_cache[sid].localcred = NULL;
538 cred = NULL;
539 }
540
541 if (cred == NULL)
542 {
543 /* We should allocate room for at least NGROUPS groups. */
544 int ngroups_max = MAX (i_grouplen, NGROUPS);
545
546 cred = (struct bsdcred *) mem_alloc (sizeof (struct bsdcred)
547 + ngroups_max * sizeof (gid_t));
548 if (cred == NULL)
549 return 0;
550
551 authdes_cache[sid].localcred = (char *) cred;
552 cred->grouplen = INVALID;
553 cred->grouplen_max = ngroups_max;
554 }
555
556 debug ("missed ucred cache");
557 *uid = cred->uid = i_uid;
558 *gid = cred->gid = i_gid;
559 cred->grouplen = i_grouplen;
560 for (i = i_grouplen - 1; i >= 0; --i)
561 cred->groups[i] = groups[i];
562 /* Make sure no too large values are reported. */
563 *grouplen = MIN (SHRT_MAX, i_grouplen);
564 return 1;
565 }
566 else if (cred->grouplen == UNKNOWN)
567 {
568 /*
569 * Already lookup up, but no match found
570 */
571 return 0;
572 }
573
574 /*
575 * cached credentials
576 */
577 *uid = cred->uid;
578 *gid = cred->gid;
579
580 /* Another stupidity in the interface: *grouplen is of type short.
581 So we might have to cut the information passed up short. */
582 int grouplen_copy = MIN (SHRT_MAX, cred->grouplen);
583 *grouplen = grouplen_copy;
584 for (i = grouplen_copy - 1; i >= 0; --i)
585 groups[i] = cred->groups[i];
586 return 1;
587}
588libc_hidden_nolink_sunrpc (authdes_getucred, GLIBC_2_1)
589
590static void
591invalidate (char *cred)
592{
593 if (cred == NULL)
594 return;
595 ((struct bsdcred *) cred)->grouplen = INVALID;
596}
597