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 |
67 | struct 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 |
79 | static struct cache_entry *authdes_cache; |
80 | static int *authdes_lru; |
81 | #endif |
82 | |
83 | static void cache_init (void) internal_function; /* initialize the cache */ |
84 | static short cache_spot (des_block *, char *, struct rpc_timeval *) |
85 | internal_function; /* find an entry in the cache */ |
86 | static void cache_ref (uint32_t sid) internal_function; |
87 | /* note that sid was ref'd */ |
88 | |
89 | static void invalidate (char *cred) internal_function; |
90 | /* invalidate entry in cache */ |
91 | |
92 | /* |
93 | * cache statistics |
94 | */ |
95 | struct |
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 | } |
101 | svcauthdes_stats; |
102 | |
103 | /* |
104 | * Service side authenticator for AUTH_DES |
105 | */ |
106 | enum 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 | ×tamp); |
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 (×tamp, &authdes_cache[sid].laststamp)) |
296 | { |
297 | debug ("timestamp before last seen" ); |
298 | return AUTH_REJECTEDVERF; /* replay */ |
299 | } |
300 | __gettimeofday (¤t, (struct timezone *) NULL); |
301 | current.tv_sec -= window; /* allow for expiration */ |
302 | if (!BEFORE (¤t, ×tamp)) |
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 | */ |
392 | static void |
393 | internal_function |
394 | cache_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 | */ |
415 | static short |
416 | cache_victim (void) |
417 | { |
418 | return authdes_lru[AUTHDES_CACHESZ - 1]; |
419 | } |
420 | |
421 | /* |
422 | * Note that sid was referenced |
423 | */ |
424 | static void |
425 | internal_function |
426 | cache_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 | */ |
447 | static short |
448 | internal_function |
449 | cache_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 | |
485 | struct 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 | */ |
500 | int |
501 | authdes_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 | } |
588 | libc_hidden_nolink_sunrpc (authdes_getucred, GLIBC_2_1) |
589 | |
590 | static void |
591 | internal_function |
592 | invalidate (char *cred) |
593 | { |
594 | if (cred == NULL) |
595 | return; |
596 | ((struct bsdcred *) cred)->grouplen = INVALID; |
597 | } |
598 | |