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); /* initialize the cache */
84static short cache_spot (des_block *, char *, struct rpc_timeval *);
85 /* find an entry in the cache */
86static void cache_ref (uint32_t sid); /* note that sid was ref'd */
87
88static void invalidate (char *cred); /* invalidate entry in cache */
89
90/*
91 * cache statistics
92 */
93struct
94 {
95 u_long ncachehits; /* times cache hit, and is not replay */
96 u_long ncachereplays; /* times cache hit, and is replay */
97 u_long ncachemisses; /* times cache missed */
98 }
99svcauthdes_stats;
100
101/*
102 * Service side authenticator for AUTH_DES
103 */
104enum auth_stat
105_svcauth_des (register struct svc_req *rqst, register struct rpc_msg *msg)
106{
107 register uint32_t *ixdr;
108 des_block cryptbuf[2];
109 register struct authdes_cred *cred;
110 struct authdes_verf verf;
111 int status;
112 register struct cache_entry *entry;
113 uint32_t sid = 0;
114 des_block *sessionkey;
115 des_block ivec;
116 u_int window;
117 struct rpc_timeval timestamp;
118 uint32_t namelen;
119 struct area
120 {
121 struct authdes_cred area_cred;
122 char area_netname[MAXNETNAMELEN + 1];
123 }
124 *area;
125
126 if (authdes_cache == NULL)
127 cache_init ();
128 if (authdes_cache == NULL) /* No free memory */
129 return AUTH_FAILED;
130
131 area = (struct area *) rqst->rq_clntcred;
132 cred = (struct authdes_cred *) &area->area_cred;
133
134 /*
135 * Get the credential
136 */
137 if (msg->rm_call.cb_cred.oa_length <= 0 ||
138 msg->rm_call.cb_cred.oa_length > MAX_AUTH_BYTES)
139 return AUTH_BADCRED;
140
141 ixdr = (uint32_t *) msg->rm_call.cb_cred.oa_base;
142 cred->adc_namekind = IXDR_GET_ENUM (ixdr, enum authdes_namekind);
143 switch (cred->adc_namekind)
144 {
145 case ADN_FULLNAME:
146 namelen = IXDR_GET_U_INT32 (ixdr);
147 if (namelen > MAXNETNAMELEN)
148 {
149 return AUTH_BADCRED;
150 }
151 cred->adc_fullname.name = area->area_netname;
152 memcpy (cred->adc_fullname.name, (char *) ixdr, namelen);
153 cred->adc_fullname.name[namelen] = 0;
154 ixdr += (RNDUP (namelen) / BYTES_PER_XDR_UNIT);
155 cred->adc_fullname.key.key.high = *ixdr++;
156 cred->adc_fullname.key.key.low = *ixdr++;
157 cred->adc_fullname.window = *ixdr++;
158 break;
159 case ADN_NICKNAME:
160 cred->adc_nickname = *ixdr++;
161 break;
162 default:
163 return AUTH_BADCRED;
164 }
165
166 /*
167 * Get the verifier
168 */
169 if (msg->rm_call.cb_verf.oa_length <= 0 ||
170 msg->rm_call.cb_verf.oa_length > MAX_AUTH_BYTES)
171 return AUTH_BADCRED;
172
173 ixdr = (uint32_t *) msg->rm_call.cb_verf.oa_base;
174 verf.adv_xtimestamp.key.high = *ixdr++;
175 verf.adv_xtimestamp.key.low = *ixdr++;
176 verf.adv_int_u = *ixdr++;
177
178 /*
179 * Get the conversation key
180 */
181 if (cred->adc_namekind == ADN_FULLNAME)
182 {
183 netobj pkey;
184 char pkey_data[1024];
185
186 sessionkey = &cred->adc_fullname.key;
187 if (!getpublickey (cred->adc_fullname.name, pkey_data))
188 {
189 debug("getpublickey");
190 return AUTH_BADCRED;
191 }
192 pkey.n_bytes = pkey_data;
193 pkey.n_len = strlen (pkey_data) + 1;
194 if (key_decryptsession_pk (cred->adc_fullname.name, &pkey,
195 sessionkey) < 0)
196 {
197 debug ("decryptsessionkey");
198 return AUTH_BADCRED; /* key not found */
199 }
200 }
201 else
202 { /* ADN_NICKNAME */
203 if (cred->adc_nickname >= AUTHDES_CACHESZ)
204 {
205 debug ("bad nickname");
206 return AUTH_BADCRED; /* garbled credential */
207 }
208 else
209 sid = cred->adc_nickname;
210
211 /* XXX This could be wrong, but else we have a
212 security problem */
213 if (authdes_cache[sid].rname == NULL)
214 return AUTH_BADCRED;
215 sessionkey = &authdes_cache[sid].key;
216 }
217
218
219 /*
220 * Decrypt the timestamp
221 */
222 cryptbuf[0] = verf.adv_xtimestamp;
223 if (cred->adc_namekind == ADN_FULLNAME)
224 {
225 cryptbuf[1].key.high = cred->adc_fullname.window;
226 cryptbuf[1].key.low = verf.adv_winverf;
227 ivec.key.high = ivec.key.low = 0;
228 status = cbc_crypt ((char *) sessionkey, (char *) cryptbuf,
229 2 * sizeof (des_block), DES_DECRYPT | DES_HW,
230 (char *) &ivec);
231 }
232 else
233 status = ecb_crypt ((char *) sessionkey, (char *) cryptbuf,
234 sizeof (des_block), DES_DECRYPT | DES_HW);
235
236 if (DES_FAILED (status))
237 {
238 debug ("decryption failure");
239 return AUTH_FAILED; /* system error */
240 }
241
242 /*
243 * XDR the decrypted timestamp
244 */
245 ixdr = (uint32_t *) cryptbuf;
246 timestamp.tv_sec = IXDR_GET_INT32 (ixdr);
247 timestamp.tv_usec = IXDR_GET_INT32 (ixdr);
248
249 /*
250 * Check for valid credentials and verifiers.
251 * They could be invalid because the key was flushed
252 * out of the cache, and so a new session should begin.
253 * Be sure and send AUTH_REJECTED{CRED, VERF} if this is the case.
254 */
255 {
256 struct timeval current;
257 int nick;
258 u_int winverf;
259
260 if (cred->adc_namekind == ADN_FULLNAME)
261 {
262 short tmp_spot;
263
264 window = IXDR_GET_U_INT32 (ixdr);
265 winverf = IXDR_GET_U_INT32 (ixdr);
266 if (winverf != window - 1)
267 {
268 debug ("window verifier mismatch");
269 return AUTH_BADCRED; /* garbled credential */
270 }
271 tmp_spot = cache_spot (sessionkey, cred->adc_fullname.name,
272 &timestamp);
273 if (tmp_spot < 0 || tmp_spot > AUTHDES_CACHESZ)
274 {
275 debug ("replayed credential");
276 return AUTH_REJECTEDCRED; /* replay */
277 }
278 sid = tmp_spot;
279 nick = 0;
280 }
281 else
282 { /* ADN_NICKNAME */
283 window = authdes_cache[sid].window;
284 nick = 1;
285 }
286
287 if (timestamp.tv_usec >= USEC_PER_SEC)
288 {
289 debug ("invalid usecs");
290 /* cached out (bad key), or garbled verifier */
291 return nick ? AUTH_REJECTEDVERF : AUTH_BADVERF;
292 }
293 if (nick && BEFORE (&timestamp, &authdes_cache[sid].laststamp))
294 {
295 debug ("timestamp before last seen");
296 return AUTH_REJECTEDVERF; /* replay */
297 }
298 __gettimeofday (&current, (struct timezone *) NULL);
299 current.tv_sec -= window; /* allow for expiration */
300 if (!BEFORE (&current, &timestamp))
301 {
302 debug ("timestamp expired");
303 /* replay, or garbled credential */
304 return nick ? AUTH_REJECTEDVERF : AUTH_BADCRED;
305 }
306 }
307
308 /*
309 * Set up the reply verifier
310 */
311 verf.adv_nickname = sid;
312
313 /*
314 * xdr the timestamp before encrypting
315 */
316 ixdr = (uint32_t *) cryptbuf;
317 IXDR_PUT_INT32 (ixdr, timestamp.tv_sec - 1);
318 IXDR_PUT_INT32 (ixdr, timestamp.tv_usec);
319
320 /*
321 * encrypt the timestamp
322 */
323 status = ecb_crypt ((char *) sessionkey, (char *) cryptbuf,
324 sizeof (des_block), DES_ENCRYPT | DES_HW);
325 if (DES_FAILED (status))
326 {
327 debug ("encryption failure");
328 return AUTH_FAILED; /* system error */
329 }
330 verf.adv_xtimestamp = cryptbuf[0];
331
332 /*
333 * Serialize the reply verifier, and update rqst
334 */
335 ixdr = (uint32_t *) msg->rm_call.cb_verf.oa_base;
336 *ixdr++ = verf.adv_xtimestamp.key.high;
337 *ixdr++ = verf.adv_xtimestamp.key.low;
338 *ixdr++ = verf.adv_int_u;
339
340 rqst->rq_xprt->xp_verf.oa_flavor = AUTH_DES;
341 rqst->rq_xprt->xp_verf.oa_base = msg->rm_call.cb_verf.oa_base;
342 rqst->rq_xprt->xp_verf.oa_length =
343 (char *) ixdr - msg->rm_call.cb_verf.oa_base;
344
345 /*
346 * We succeeded, commit the data to the cache now and
347 * finish cooking the credential.
348 */
349 entry = &authdes_cache[sid];
350 entry->laststamp = timestamp;
351 cache_ref (sid);
352 if (cred->adc_namekind == ADN_FULLNAME)
353 {
354 size_t full_len;
355
356 cred->adc_fullname.window = window;
357 cred->adc_nickname = sid; /* save nickname */
358 if (entry->rname != NULL)
359 mem_free (entry->rname, strlen (entry->rname) + 1);
360 full_len = strlen (cred->adc_fullname.name) + 1;
361 entry->rname = mem_alloc ((u_int) full_len);
362 if (entry->rname != NULL)
363 memcpy (entry->rname, cred->adc_fullname.name, full_len);
364 else
365 {
366 debug ("out of memory");
367 return AUTH_FAILED; /* out of memory is bad */
368 }
369 entry->key = *sessionkey;
370 entry->window = window;
371 invalidate (entry->localcred); /* mark any cached cred invalid */
372 }
373 else
374 { /* ADN_NICKNAME */
375 /*
376 * nicknames are cooked into fullnames
377 */
378 cred->adc_namekind = ADN_FULLNAME;
379 cred->adc_fullname.name = entry->rname;
380 cred->adc_fullname.key = entry->key;
381 cred->adc_fullname.window = entry->window;
382 }
383 return AUTH_OK; /* we made it! */
384}
385
386
387/*
388 * Initialize the cache
389 */
390static void
391cache_init (void)
392{
393 register int i;
394
395 authdes_cache = (struct cache_entry *)
396 calloc (sizeof (struct cache_entry) * AUTHDES_CACHESZ, 1);
397 if (authdes_cache == NULL)
398 return;
399
400 authdes_lru = (int *) mem_alloc (sizeof (int) * AUTHDES_CACHESZ);
401 /*
402 * Initialize the lru list
403 */
404 for (i = 0; i < AUTHDES_CACHESZ; ++i)
405 authdes_lru[i] = i;
406}
407
408
409/*
410 * Find the lru victim
411 */
412static short
413cache_victim (void)
414{
415 return authdes_lru[AUTHDES_CACHESZ - 1];
416}
417
418/*
419 * Note that sid was referenced
420 */
421static void
422cache_ref (register uint32_t sid)
423{
424 register int i;
425 register int curr;
426 register int prev;
427
428 prev = authdes_lru[0];
429 authdes_lru[0] = sid;
430 for (i = 1; prev != sid; ++i)
431 {
432 curr = authdes_lru[i];
433 authdes_lru[i] = prev;
434 prev = curr;
435 }
436}
437
438/*
439 * Find a spot in the cache for a credential containing
440 * the items given. Return -1 if a replay is detected, otherwise
441 * return the spot in the cache.
442 */
443static short
444cache_spot (register des_block *key, char *name,
445 struct rpc_timeval *timestamp)
446{
447 register struct cache_entry *cp;
448 register int i;
449 register uint32_t hi;
450
451 hi = key->key.high;
452 for (cp = authdes_cache, i = 0; i < AUTHDES_CACHESZ; ++i, ++cp)
453 {
454 if (cp->key.key.high == hi &&
455 cp->key.key.low == key->key.low &&
456 cp->rname != NULL &&
457 memcmp (cp->rname, name, strlen (name) + 1) == 0)
458 {
459 if (BEFORE (timestamp, &cp->laststamp))
460 {
461 ++svcauthdes_stats.ncachereplays;
462 return -1; /* replay */
463 }
464 ++svcauthdes_stats.ncachehits;
465 return i; /* refresh */
466 }
467 }
468 ++svcauthdes_stats.ncachemisses;
469 return cache_victim (); /* new credential */
470}
471
472/*
473 * Local credential handling stuff.
474 * NOTE: bsd unix dependent.
475 * Other operating systems should put something else here.
476 */
477#define UNKNOWN -2 /* grouplen, if cached cred is unknown user */
478#define INVALID -1 /* grouplen, if cache entry is invalid */
479
480struct bsdcred
481{
482 uid_t uid; /* cached uid */
483 gid_t gid; /* cached gid */
484 int grouplen; /* length of cached groups */
485 int grouplen_max; /* length of allocated cached groups */
486 gid_t groups[0]; /* cached groups */
487};
488
489/*
490 * Map a des credential into a unix cred.
491 * We cache the credential here so the application does
492 * not have to make an rpc call every time to interpret
493 * the credential.
494 */
495int
496authdes_getucred (const struct authdes_cred *adc, uid_t * uid, gid_t * gid,
497 short *grouplen, gid_t * groups)
498{
499 unsigned sid;
500 register int i;
501 uid_t i_uid;
502 gid_t i_gid;
503 int i_grouplen;
504 struct bsdcred *cred;
505
506 sid = adc->adc_nickname;
507 if (sid >= AUTHDES_CACHESZ)
508 {
509 debug ("invalid nickname");
510 return 0;
511 }
512 cred = (struct bsdcred *) authdes_cache[sid].localcred;
513 if (cred == NULL || cred->grouplen == INVALID)
514 {
515 /*
516 * not in cache: lookup
517 */
518 if (!netname2user (adc->adc_fullname.name, &i_uid, &i_gid,
519 &i_grouplen, groups))
520 {
521 debug ("unknown netname");
522 if (cred != NULL)
523 cred->grouplen = UNKNOWN; /* mark as lookup up, but not found */
524 return 0;
525 }
526
527 if (cred != NULL && cred->grouplen_max < i_grouplen)
528 {
529 /* We already have an allocated data structure. But it is
530 too small. */
531 free (cred);
532 authdes_cache[sid].localcred = NULL;
533 cred = NULL;
534 }
535
536 if (cred == NULL)
537 {
538 /* We should allocate room for at least NGROUPS groups. */
539 int ngroups_max = MAX (i_grouplen, NGROUPS);
540
541 cred = (struct bsdcred *) mem_alloc (sizeof (struct bsdcred)
542 + ngroups_max * sizeof (gid_t));
543 if (cred == NULL)
544 return 0;
545
546 authdes_cache[sid].localcred = (char *) cred;
547 cred->grouplen = INVALID;
548 cred->grouplen_max = ngroups_max;
549 }
550
551 debug ("missed ucred cache");
552 *uid = cred->uid = i_uid;
553 *gid = cred->gid = i_gid;
554 cred->grouplen = i_grouplen;
555 for (i = i_grouplen - 1; i >= 0; --i)
556 cred->groups[i] = groups[i];
557 /* Make sure no too large values are reported. */
558 *grouplen = MIN (SHRT_MAX, i_grouplen);
559 return 1;
560 }
561 else if (cred->grouplen == UNKNOWN)
562 {
563 /*
564 * Already lookup up, but no match found
565 */
566 return 0;
567 }
568
569 /*
570 * cached credentials
571 */
572 *uid = cred->uid;
573 *gid = cred->gid;
574
575 /* Another stupidity in the interface: *grouplen is of type short.
576 So we might have to cut the information passed up short. */
577 int grouplen_copy = MIN (SHRT_MAX, cred->grouplen);
578 *grouplen = grouplen_copy;
579 for (i = grouplen_copy - 1; i >= 0; --i)
580 groups[i] = cred->groups[i];
581 return 1;
582}
583libc_hidden_nolink_sunrpc (authdes_getucred, GLIBC_2_1)
584
585static void
586invalidate (char *cred)
587{
588 if (cred == NULL)
589 return;
590 ((struct bsdcred *) cred)->grouplen = INVALID;
591}
592