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 <sys/param.h>
48#include <netinet/in.h>
49#include <rpc/rpc.h>
50#include <rpc/xdr.h>
51#include <rpc/auth.h>
52#include <rpc/auth_des.h>
53#include <rpc/svc_auth.h>
54#include <rpc/svc.h>
55#include <rpc/des_crypt.h>
56#include <shlib-compat.h>
57
58#define debug(msg) /*printf("svcauth_des: %s\n", msg) */
59
60#define USEC_PER_SEC ((uint32_t) 1000000L)
61#define BEFORE(t1, t2) timercmp(t1, t2, <)
62
63/*
64 * LRU cache of conversation keys and some other useful items.
65 */
66#define AUTHDES_CACHESZ 64
67struct cache_entry
68 {
69 des_block key; /* conversation key */
70 char *rname; /* client's name */
71 u_int window; /* credential lifetime window */
72 struct rpc_timeval laststamp; /* detect replays of creds */
73 char *localcred; /* generic local credential */
74 };
75#ifdef _RPC_THREAD_SAFE_
76#define authdes_cache RPC_THREAD_VARIABLE(authdes_cache_s)
77#define authdes_lru RPC_THREAD_VARIABLE(authdes_lru_s)
78#else
79static struct cache_entry *authdes_cache;
80static int *authdes_lru;
81#endif
82
83static void cache_init (void) internal_function; /* initialize the cache */
84static short cache_spot (des_block *, char *, struct rpc_timeval *)
85 internal_function; /* find an entry in the cache */
86static void cache_ref (uint32_t sid) internal_function;
87 /* note that sid was ref'd */
88
89static void invalidate (char *cred) internal_function;
90 /* invalidate entry in cache */
91
92/*
93 * cache statistics
94 */
95struct
96 {
97 u_long ncachehits; /* times cache hit, and is not replay */
98 u_long ncachereplays; /* times cache hit, and is replay */
99 u_long ncachemisses; /* times cache missed */
100 }
101svcauthdes_stats;
102
103/*
104 * Service side authenticator for AUTH_DES
105 */
106enum auth_stat
107_svcauth_des (register struct svc_req *rqst, register struct rpc_msg *msg)
108{
109 register uint32_t *ixdr;
110 des_block cryptbuf[2];
111 register struct authdes_cred *cred;
112 struct authdes_verf verf;
113 int status;
114 register struct cache_entry *entry;
115 uint32_t sid = 0;
116 des_block *sessionkey;
117 des_block ivec;
118 u_int window;
119 struct rpc_timeval timestamp;
120 uint32_t namelen;
121 struct area
122 {
123 struct authdes_cred area_cred;
124 char area_netname[MAXNETNAMELEN + 1];
125 }
126 *area;
127
128 if (authdes_cache == NULL)
129 cache_init ();
130 if (authdes_cache == NULL) /* No free memory */
131 return AUTH_FAILED;
132
133 area = (struct area *) rqst->rq_clntcred;
134 cred = (struct authdes_cred *) &area->area_cred;
135
136 /*
137 * Get the credential
138 */
139 if (msg->rm_call.cb_cred.oa_length <= 0 ||
140 msg->rm_call.cb_cred.oa_length > MAX_AUTH_BYTES)
141 return AUTH_BADCRED;
142
143 ixdr = (uint32_t *) msg->rm_call.cb_cred.oa_base;
144 cred->adc_namekind = IXDR_GET_ENUM (ixdr, enum authdes_namekind);
145 switch (cred->adc_namekind)
146 {
147 case ADN_FULLNAME:
148 namelen = IXDR_GET_U_INT32 (ixdr);
149 if (namelen > MAXNETNAMELEN)
150 {
151 return AUTH_BADCRED;
152 }
153 cred->adc_fullname.name = area->area_netname;
154 memcpy (cred->adc_fullname.name, (char *) ixdr, namelen);
155 cred->adc_fullname.name[namelen] = 0;
156 ixdr += (RNDUP (namelen) / BYTES_PER_XDR_UNIT);
157 cred->adc_fullname.key.key.high = *ixdr++;
158 cred->adc_fullname.key.key.low = *ixdr++;
159 cred->adc_fullname.window = *ixdr++;
160 break;
161 case ADN_NICKNAME:
162 cred->adc_nickname = *ixdr++;
163 break;
164 default:
165 return AUTH_BADCRED;
166 }
167
168 /*
169 * Get the verifier
170 */
171 if (msg->rm_call.cb_verf.oa_length <= 0 ||
172 msg->rm_call.cb_verf.oa_length > MAX_AUTH_BYTES)
173 return AUTH_BADCRED;
174
175 ixdr = (uint32_t *) msg->rm_call.cb_verf.oa_base;
176 verf.adv_xtimestamp.key.high = *ixdr++;
177 verf.adv_xtimestamp.key.low = *ixdr++;
178 verf.adv_int_u = *ixdr++;
179
180 /*
181 * Get the conversation key
182 */
183 if (cred->adc_namekind == ADN_FULLNAME)
184 {
185 netobj pkey;
186 char pkey_data[1024];
187
188 sessionkey = &cred->adc_fullname.key;
189 if (!getpublickey (cred->adc_fullname.name, pkey_data))
190 {
191 debug("getpublickey");
192 return AUTH_BADCRED;
193 }
194 pkey.n_bytes = pkey_data;
195 pkey.n_len = strlen (pkey_data) + 1;
196 if (key_decryptsession_pk (cred->adc_fullname.name, &pkey,
197 sessionkey) < 0)
198 {
199 debug ("decryptsessionkey");
200 return AUTH_BADCRED; /* key not found */
201 }
202 }
203 else
204 { /* ADN_NICKNAME */
205 if (cred->adc_nickname >= AUTHDES_CACHESZ)
206 {
207 debug ("bad nickname");
208 return AUTH_BADCRED; /* garbled credential */
209 }
210 else
211 sid = cred->adc_nickname;
212
213 /* XXX This could be wrong, but else we have a
214 security problem */
215 if (authdes_cache[sid].rname == NULL)
216 return AUTH_BADCRED;
217 sessionkey = &authdes_cache[sid].key;
218 }
219
220
221 /*
222 * Decrypt the timestamp
223 */
224 cryptbuf[0] = verf.adv_xtimestamp;
225 if (cred->adc_namekind == ADN_FULLNAME)
226 {
227 cryptbuf[1].key.high = cred->adc_fullname.window;
228 cryptbuf[1].key.low = verf.adv_winverf;
229 ivec.key.high = ivec.key.low = 0;
230 status = cbc_crypt ((char *) sessionkey, (char *) cryptbuf,
231 2 * sizeof (des_block), DES_DECRYPT | DES_HW,
232 (char *) &ivec);
233 }
234 else
235 status = ecb_crypt ((char *) sessionkey, (char *) cryptbuf,
236 sizeof (des_block), DES_DECRYPT | DES_HW);
237
238 if (DES_FAILED (status))
239 {
240 debug ("decryption failure");
241 return AUTH_FAILED; /* system error */
242 }
243
244 /*
245 * XDR the decrypted timestamp
246 */
247 ixdr = (uint32_t *) cryptbuf;
248 timestamp.tv_sec = IXDR_GET_INT32 (ixdr);
249 timestamp.tv_usec = IXDR_GET_INT32 (ixdr);
250
251 /*
252 * Check for valid credentials and verifiers.
253 * They could be invalid because the key was flushed
254 * out of the cache, and so a new session should begin.
255 * Be sure and send AUTH_REJECTED{CRED, VERF} if this is the case.
256 */
257 {
258 struct timeval current;
259 int nick;
260 u_int winverf;
261
262 if (cred->adc_namekind == ADN_FULLNAME)
263 {
264 short tmp_spot;
265
266 window = IXDR_GET_U_INT32 (ixdr);
267 winverf = IXDR_GET_U_INT32 (ixdr);
268 if (winverf != window - 1)
269 {
270 debug ("window verifier mismatch");
271 return AUTH_BADCRED; /* garbled credential */
272 }
273 tmp_spot = cache_spot (sessionkey, cred->adc_fullname.name,
274 &timestamp);
275 if (tmp_spot < 0 || tmp_spot > AUTHDES_CACHESZ)
276 {
277 debug ("replayed credential");
278 return AUTH_REJECTEDCRED; /* replay */
279 }
280 sid = tmp_spot;
281 nick = 0;
282 }
283 else
284 { /* ADN_NICKNAME */
285 window = authdes_cache[sid].window;
286 nick = 1;
287 }
288
289 if (timestamp.tv_usec >= USEC_PER_SEC)
290 {
291 debug ("invalid usecs");
292 /* cached out (bad key), or garbled verifier */
293 return nick ? AUTH_REJECTEDVERF : AUTH_BADVERF;
294 }
295 if (nick && BEFORE (&timestamp, &authdes_cache[sid].laststamp))
296 {
297 debug ("timestamp before last seen");
298 return AUTH_REJECTEDVERF; /* replay */
299 }
300 __gettimeofday (&current, (struct timezone *) NULL);
301 current.tv_sec -= window; /* allow for expiration */
302 if (!BEFORE (&current, &timestamp))
303 {
304 debug ("timestamp expired");
305 /* replay, or garbled credential */
306 return nick ? AUTH_REJECTEDVERF : AUTH_BADCRED;
307 }
308 }
309
310 /*
311 * Set up the reply verifier
312 */
313 verf.adv_nickname = sid;
314
315 /*
316 * xdr the timestamp before encrypting
317 */
318 ixdr = (uint32_t *) cryptbuf;
319 IXDR_PUT_INT32 (ixdr, timestamp.tv_sec - 1);
320 IXDR_PUT_INT32 (ixdr, timestamp.tv_usec);
321
322 /*
323 * encrypt the timestamp
324 */
325 status = ecb_crypt ((char *) sessionkey, (char *) cryptbuf,
326 sizeof (des_block), DES_ENCRYPT | DES_HW);
327 if (DES_FAILED (status))
328 {
329 debug ("encryption failure");
330 return AUTH_FAILED; /* system error */
331 }
332 verf.adv_xtimestamp = cryptbuf[0];
333
334 /*
335 * Serialize the reply verifier, and update rqst
336 */
337 ixdr = (uint32_t *) msg->rm_call.cb_verf.oa_base;
338 *ixdr++ = verf.adv_xtimestamp.key.high;
339 *ixdr++ = verf.adv_xtimestamp.key.low;
340 *ixdr++ = verf.adv_int_u;
341
342 rqst->rq_xprt->xp_verf.oa_flavor = AUTH_DES;
343 rqst->rq_xprt->xp_verf.oa_base = msg->rm_call.cb_verf.oa_base;
344 rqst->rq_xprt->xp_verf.oa_length =
345 (char *) ixdr - msg->rm_call.cb_verf.oa_base;
346
347 /*
348 * We succeeded, commit the data to the cache now and
349 * finish cooking the credential.
350 */
351 entry = &authdes_cache[sid];
352 entry->laststamp = timestamp;
353 cache_ref (sid);
354 if (cred->adc_namekind == ADN_FULLNAME)
355 {
356 size_t full_len;
357
358 cred->adc_fullname.window = window;
359 cred->adc_nickname = sid; /* save nickname */
360 if (entry->rname != NULL)
361 mem_free (entry->rname, strlen (entry->rname) + 1);
362 full_len = strlen (cred->adc_fullname.name) + 1;
363 entry->rname = mem_alloc ((u_int) full_len);
364 if (entry->rname != NULL)
365 memcpy (entry->rname, cred->adc_fullname.name, full_len);
366 else
367 {
368 debug ("out of memory");
369 return AUTH_FAILED; /* out of memory is bad */
370 }
371 entry->key = *sessionkey;
372 entry->window = window;
373 invalidate (entry->localcred); /* mark any cached cred invalid */
374 }
375 else
376 { /* ADN_NICKNAME */
377 /*
378 * nicknames are cooked into fullnames
379 */
380 cred->adc_namekind = ADN_FULLNAME;
381 cred->adc_fullname.name = entry->rname;
382 cred->adc_fullname.key = entry->key;
383 cred->adc_fullname.window = entry->window;
384 }
385 return AUTH_OK; /* we made it! */
386}
387
388
389/*
390 * Initialize the cache
391 */
392static void
393internal_function
394cache_init (void)
395{
396 register int i;
397
398 authdes_cache = (struct cache_entry *)
399 calloc (sizeof (struct cache_entry) * AUTHDES_CACHESZ, 1);
400 if (authdes_cache == NULL)
401 return;
402
403 authdes_lru = (int *) mem_alloc (sizeof (int) * AUTHDES_CACHESZ);
404 /*
405 * Initialize the lru list
406 */
407 for (i = 0; i < AUTHDES_CACHESZ; ++i)
408 authdes_lru[i] = i;
409}
410
411
412/*
413 * Find the lru victim
414 */
415static short
416cache_victim (void)
417{
418 return authdes_lru[AUTHDES_CACHESZ - 1];
419}
420
421/*
422 * Note that sid was referenced
423 */
424static void
425internal_function
426cache_ref (register uint32_t sid)
427{
428 register int i;
429 register int curr;
430 register int prev;
431
432 prev = authdes_lru[0];
433 authdes_lru[0] = sid;
434 for (i = 1; prev != sid; ++i)
435 {
436 curr = authdes_lru[i];
437 authdes_lru[i] = prev;
438 prev = curr;
439 }
440}
441
442/*
443 * Find a spot in the cache for a credential containing
444 * the items given. Return -1 if a replay is detected, otherwise
445 * return the spot in the cache.
446 */
447static short
448internal_function
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
591internal_function
592invalidate (char *cred)
593{
594 if (cred == NULL)
595 return;
596 ((struct bsdcred *) cred)->grouplen = INVALID;
597}
598