1 /*
2 * Neil Brown <neilb@cse.unsw.edu.au>
3 * J. Bruce Fields <bfields@umich.edu>
4 * Andy Adamson <andros@umich.edu>
5 * Dug Song <dugsong@monkey.org>
6 *
7 * RPCSEC_GSS server authentication.
8 * This implements RPCSEC_GSS as defined in rfc2203 (rpcsec_gss) and rfc2078
9 * (gssapi)
10 *
11 * The RPCSEC_GSS involves three stages:
12 * 1/ context creation
13 * 2/ data exchange
14 * 3/ context destruction
15 *
16 * Context creation is handled largely by upcalls to user-space.
17 * In particular, GSS_Accept_sec_context is handled by an upcall
18 * Data exchange is handled entirely within the kernel
19 * In particular, GSS_GetMIC, GSS_VerifyMIC, GSS_Seal, GSS_Unseal are in-kernel.
20 * Context destruction is handled in-kernel
21 * GSS_Delete_sec_context is in-kernel
22 *
23 * Context creation is initiated by a RPCSEC_GSS_INIT request arriving.
24 * The context handle and gss_token are used as a key into the rpcsec_init cache.
25 * The content of this cache includes some of the outputs of GSS_Accept_sec_context,
26 * being major_status, minor_status, context_handle, reply_token.
27 * These are sent back to the client.
28 * Sequence window management is handled by the kernel. The window size if currently
29 * a compile time constant.
30 *
31 * When user-space is happy that a context is established, it places an entry
32 * in the rpcsec_context cache. The key for this cache is the context_handle.
33 * The content includes:
34 * uid/gidlist - for determining access rights
35 * mechanism type
36 * mechanism specific information, such as a key
37 *
38 */
39
40 #include <linux/types.h>
41 #include <linux/module.h>
42 #include <linux/pagemap.h>
43
44 #include <linux/sunrpc/auth_gss.h>
45 #include <linux/sunrpc/svcauth.h>
46 #include <linux/sunrpc/gss_err.h>
47 #include <linux/sunrpc/svcauth.h>
48 #include <linux/sunrpc/svcauth_gss.h>
49 #include <linux/sunrpc/cache.h>
50
51 #ifdef RPC_DEBUG
52 # define RPCDBG_FACILITY RPCDBG_AUTH
53 #endif
54
55 /* The rpcsec_init cache is used for mapping RPCSEC_GSS_{,CONT_}INIT requests
56 * into replies.
57 *
58 * Key is context handle (\x if empty) and gss_token.
59 * Content is major_status minor_status (integers) context_handle, reply_token.
60 *
61 */
62
63 static int netobj_equal(struct xdr_netobj *a, struct xdr_netobj *b)
64 {
65 return a->len == b->len && 0 == memcmp(a->data, b->data, a->len);
66 }
67
68 #define RSI_HASHBITS 6
69 #define RSI_HASHMAX (1<<RSI_HASHBITS)
70 #define RSI_HASHMASK (RSI_HASHMAX-1)
71
72 struct rsi {
73 struct cache_head h;
74 struct xdr_netobj in_handle, in_token;
75 struct xdr_netobj out_handle, out_token;
76 int major_status, minor_status;
77 };
78
79 static struct cache_head *rsi_table[RSI_HASHMAX];
80 static struct cache_detail rsi_cache;
81 static struct rsi *rsi_lookup(struct rsi *item, int set);
82
83 static void rsi_free(struct rsi *rsii)
84 {
85 kfree(rsii->in_handle.data);
86 kfree(rsii->in_token.data);
87 kfree(rsii->out_handle.data);
88 kfree(rsii->out_token.data);
89 }
90
91 static void rsi_put(struct cache_head *item, struct cache_detail *cd)
92 {
93 struct rsi *rsii = container_of(item, struct rsi, h);
94 if (cache_put(item, cd)) {
95 rsi_free(rsii);
96 kfree(rsii);
97 }
98 }
99
100 static inline int rsi_hash(struct rsi *item)
101 {
102 return hash_mem(item->in_handle.data, item->in_handle.len, RSI_HASHBITS)
103 ^ hash_mem(item->in_token.data, item->in_token.len, RSI_HASHBITS);
104 }
105
106 static inline int rsi_match(struct rsi *item, struct rsi *tmp)
107 {
108 return netobj_equal(&item->in_handle, &tmp->in_handle)
109 && netobj_equal(&item->in_token, &tmp->in_token);
110 }
111
112 static int dup_to_netobj(struct xdr_netobj *dst, char *src, int len)
113 {
114 dst->len = len;
115 dst->data = (len ? kmalloc(len, GFP_KERNEL) : NULL);
116 if (dst->data)
117 memcpy(dst->data, src, len);
118 if (len && !dst->data)
119 return -ENOMEM;
120 return 0;
121 }
122
123 static inline int dup_netobj(struct xdr_netobj *dst, struct xdr_netobj *src)
124 {
125 return dup_to_netobj(dst, src->data, src->len);
126 }
127
128 static inline void rsi_init(struct rsi *new, struct rsi *item)
129 {
130 new->out_handle.data = NULL;
131 new->out_handle.len = 0;
132 new->out_token.data = NULL;
133 new->out_token.len = 0;
134 new->in_handle.len = item->in_handle.len;
135 item->in_handle.len = 0;
136 new->in_token.len = item->in_token.len;
137 item->in_token.len = 0;
138 new->in_handle.data = item->in_handle.data;
139 item->in_handle.data = NULL;
140 new->in_token.data = item->in_token.data;
141 item->in_token.data = NULL;
142 }
143
144 static inline void rsi_update(struct rsi *new, struct rsi *item)
145 {
146 BUG_ON(new->out_handle.data || new->out_token.data);
147 new->out_handle.len = item->out_handle.len;
148 item->out_handle.len = 0;
149 new->out_token.len = item->out_token.len;
150 item->out_token.len = 0;
151 new->out_handle.data = item->out_handle.data;
152 item->out_handle.data = NULL;
153 new->out_token.data = item->out_token.data;
154 item->out_token.data = NULL;
155
156 new->major_status = item->major_status;
157 new->minor_status = item->minor_status;
158 }
159
160 static void rsi_request(struct cache_detail *cd,
161 struct cache_head *h,
162 char **bpp, int *blen)
163 {
164 struct rsi *rsii = container_of(h, struct rsi, h);
165
166 qword_addhex(bpp, blen, rsii->in_handle.data, rsii->in_handle.len);
167 qword_addhex(bpp, blen, rsii->in_token.data, rsii->in_token.len);
168 (*bpp)[-1] = '\n';
169 }
170
171
172 static int rsi_parse(struct cache_detail *cd,
173 char *mesg, int mlen)
174 {
175 /* context token expiry major minor context token */
176 char *buf = mesg;
177 char *ep;
178 int len;
179 struct rsi rsii, *rsip = NULL;
180 time_t expiry;
181 int status = -EINVAL;
182
183 memset(&rsii, 0, sizeof(rsii));
184 /* handle */
185 len = qword_get(&mesg, buf, mlen);
186 if (len < 0)
187 goto out;
188 status = -ENOMEM;
189 if (dup_to_netobj(&rsii.in_handle, buf, len))
190 goto out;
191
192 /* token */
193 len = qword_get(&mesg, buf, mlen);
194 status = -EINVAL;
195 if (len < 0)
196 goto out;
197 status = -ENOMEM;
198 if (dup_to_netobj(&rsii.in_token, buf, len))
199 goto out;
200
201 rsii.h.flags = 0;
202 /* expiry */
203 expiry = get_expiry(&mesg);
204 status = -EINVAL;
205 if (expiry == 0)
206 goto out;
207
208 /* major/minor */
209 len = qword_get(&mesg, buf, mlen);
210 if (len < 0)
211 goto out;
212 if (len == 0) {
213 goto out;
214 } else {
215 rsii.major_status = simple_strtoul(buf, &ep, 10);
216 if (*ep)
217 goto out;
218 len = qword_get(&mesg, buf, mlen);
219 if (len <= 0)
220 goto out;
221 rsii.minor_status = simple_strtoul(buf, &ep, 10);
222 if (*ep)
223 goto out;
224
225 /* out_handle */
226 len = qword_get(&mesg, buf, mlen);
227 if (len < 0)
228 goto out;
229 status = -ENOMEM;
230 if (dup_to_netobj(&rsii.out_handle, buf, len))
231 goto out;
232
233 /* out_token */
234 len = qword_get(&mesg, buf, mlen);
235 status = -EINVAL;
236 if (len < 0)
237 goto out;
238 status = -ENOMEM;
239 if (dup_to_netobj(&rsii.out_token, buf, len))
240 goto out;
241 }
242 rsii.h.expiry_time = expiry;
243 rsip = rsi_lookup(&rsii, 1);
244 status = 0;
245 out:
246 rsi_free(&rsii);
247 if (rsip)
248 rsi_put(&rsip->h, &rsi_cache);
249 return status;
250 }
251
252 static struct cache_detail rsi_cache = {
253 .hash_size = RSI_HASHMAX,
254 .hash_table = rsi_table,
255 .name = "auth.rpcsec.init",
256 .cache_put = rsi_put,
257 .cache_request = rsi_request,
258 .cache_parse = rsi_parse,
259 };
260
261 static DefineSimpleCacheLookup(rsi, 0)
262
263 /*
264 * The rpcsec_context cache is used to store a context that is
265 * used in data exchange.
266 * The key is a context handle. The content is:
267 * uid, gidlist, mechanism, service-set, mech-specific-data
268 */
269
270 #define RSC_HASHBITS 10
271 #define RSC_HASHMAX (1<<RSC_HASHBITS)
272 #define RSC_HASHMASK (RSC_HASHMAX-1)
273
274 #define GSS_SEQ_WIN 128
275
276 struct gss_svc_seq_data {
277 /* highest seq number seen so far: */
278 int sd_max;
279 /* for i such that sd_max-GSS_SEQ_WIN < i <= sd_max, the i-th bit of
280 * sd_win is nonzero iff sequence number i has been seen already: */
281 unsigned long sd_win[GSS_SEQ_WIN/BITS_PER_LONG];
282 spinlock_t sd_lock;
283 };
284
285 struct rsc {
286 struct cache_head h;
287 struct xdr_netobj handle;
288 struct svc_cred cred;
289 struct gss_svc_seq_data seqdata;
290 struct gss_ctx *mechctx;
291 };
292
293 static struct cache_head *rsc_table[RSC_HASHMAX];
294 static struct cache_detail rsc_cache;
295 static struct rsc *rsc_lookup(struct rsc *item, int set);
296
297 static void rsc_free(struct rsc *rsci)
298 {
299 kfree(rsci->handle.data);
300 if (rsci->mechctx)
301 gss_delete_sec_context(&rsci->mechctx);
302 if (rsci->cred.cr_group_info)
303 put_group_info(rsci->cred.cr_group_info);
304 }
305
306 static void rsc_put(struct cache_head *item, struct cache_detail *cd)
307 {
308 struct rsc *rsci = container_of(item, struct rsc, h);
309
310 if (cache_put(item, cd)) {
311 rsc_free(rsci);
312 kfree(rsci);
313 }
314 }
315
316 static inline int
317 rsc_hash(struct rsc *rsci)
318 {
319 return hash_mem(rsci->handle.data, rsci->handle.len, RSC_HASHBITS);
320 }
321
322 static inline int
323 rsc_match(struct rsc *new, struct rsc *tmp)
324 {
325 return netobj_equal(&new->handle, &tmp->handle);
326 }
327
328 static inline void
329 rsc_init(struct rsc *new, struct rsc *tmp)
330 {
331 new->handle.len = tmp->handle.len;
332 tmp->handle.len = 0;
333 new->handle.data = tmp->handle.data;
334 tmp->handle.data = NULL;
335 new->mechctx = NULL;
336 new->cred.cr_group_info = NULL;
337 }
338
339 static inline void
340 rsc_update(struct rsc *new, struct rsc *tmp)
341 {
342 new->mechctx = tmp->mechctx;
343 tmp->mechctx = NULL;
344 memset(&new->seqdata, 0, sizeof(new->seqdata));
345 spin_lock_init(&new->seqdata.sd_lock);
346 new->cred = tmp->cred;
347 tmp->cred.cr_group_info = NULL;
348 }
349
350 static int rsc_parse(struct cache_detail *cd,
351 char *mesg, int mlen)
352 {
353 /* contexthandle expiry [ uid gid N <n gids> mechname ...mechdata... ] */
354 char *buf = mesg;
355 int len, rv;
356 struct rsc rsci, *rscp = NULL;
357 time_t expiry;
358 int status = -EINVAL;
359
360 memset(&rsci, 0, sizeof(rsci));
361 /* context handle */
362 len = qword_get(&mesg, buf, mlen);
363 if (len < 0) goto out;
364 status = -ENOMEM;
365 if (dup_to_netobj(&rsci.handle, buf, len))
366 goto out;
367
368 rsci.h.flags = 0;
369 /* expiry */
370 expiry = get_expiry(&mesg);
371 status = -EINVAL;
372 if (expiry == 0)
373 goto out;
374
375 /* uid, or NEGATIVE */
376 rv = get_int(&mesg, &rsci.cred.cr_uid);
377 if (rv == -EINVAL)
378 goto out;
379 if (rv == -ENOENT)
380 set_bit(CACHE_NEGATIVE, &rsci.h.flags);
381 else {
382 int N, i;
383 struct gss_api_mech *gm;
384 struct xdr_netobj tmp_buf;
385
386 /* gid */
387 if (get_int(&mesg, &rsci.cred.cr_gid))
388 goto out;
389
390 /* number of additional gid's */
391 if (get_int(&mesg, &N))
392 goto out;
393 status = -ENOMEM;
394 rsci.cred.cr_group_info = groups_alloc(N);
395 if (rsci.cred.cr_group_info == NULL)
396 goto out;
397
398 /* gid's */
399 status = -EINVAL;
400 for (i=0; i<N; i++) {
401 gid_t gid;
402 if (get_int(&mesg, &gid))
403 goto out;
404 GROUP_AT(rsci.cred.cr_group_info, i) = gid;
405 }
406
407 /* mech name */
408 len = qword_get(&mesg, buf, mlen);
409 if (len < 0)
410 goto out;
411 gm = gss_mech_get_by_name(buf);
412 status = -EOPNOTSUPP;
413 if (!gm)
414 goto out;
415
416 status = -EINVAL;
417 /* mech-specific data: */
418 len = qword_get(&mesg, buf, mlen);
419 if (len < 0) {
420 gss_mech_put(gm);
421 goto out;
422 }
423 tmp_buf.len = len;
424 tmp_buf.data = buf;
425 if (gss_import_sec_context(&tmp_buf, gm, &rsci.mechctx)) {
426 gss_mech_put(gm);
427 goto out;
428 }
429 gss_mech_put(gm);
430 }
431 rsci.h.expiry_time = expiry;
432 rscp = rsc_lookup(&rsci, 1);
433 status = 0;
434 out:
435 rsc_free(&rsci);
436 if (rscp)
437 rsc_put(&rscp->h, &rsc_cache);
438 return status;
439 }
440
441 static struct cache_detail rsc_cache = {
442 .hash_size = RSC_HASHMAX,
443 .hash_table = rsc_table,
444 .name = "auth.rpcsec.context",
445 .cache_put = rsc_put,
446 .cache_parse = rsc_parse,
447 };
448
449 static DefineSimpleCacheLookup(rsc, 0);
450
451 static struct rsc *
452 gss_svc_searchbyctx(struct xdr_netobj *handle)
453 {
454 struct rsc rsci;
455 struct rsc *found;
456
457 memset(&rsci, 0, sizeof(rsci));
458 if (dup_to_netobj(&rsci.handle, handle->data, handle->len))
459 return NULL;
460 found = rsc_lookup(&rsci, 0);
461 rsc_free(&rsci);
462 if (!found)
463 return NULL;
464 if (cache_check(&rsc_cache, &found->h, NULL))
465 return NULL;
466 return found;
467 }
468
469 /* Implements sequence number algorithm as specified in RFC 2203. */
470 static int
471 gss_check_seq_num(struct rsc *rsci, int seq_num)
472 {
473 struct gss_svc_seq_data *sd = &rsci->seqdata;
474
475 spin_lock(&sd->sd_lock);
476 if (seq_num > sd->sd_max) {
477 if (seq_num >= sd->sd_max + GSS_SEQ_WIN) {
478 memset(sd->sd_win,0,sizeof(sd->sd_win));
479 sd->sd_max = seq_num;
480 } else while (sd->sd_max < seq_num) {
481 sd->sd_max++;
482 __clear_bit(sd->sd_max % GSS_SEQ_WIN, sd->sd_win);
483 }
484 __set_bit(seq_num % GSS_SEQ_WIN, sd->sd_win);
485 goto ok;
486 } else if (seq_num <= sd->sd_max - GSS_SEQ_WIN) {
487 goto drop;
488 }
489 /* sd_max - GSS_SEQ_WIN < seq_num <= sd_max */
490 if (__test_and_set_bit(seq_num % GSS_SEQ_WIN, sd->sd_win))
491 goto drop;
492 ok:
493 spin_unlock(&sd->sd_lock);
494 return 1;
495 drop:
496 spin_unlock(&sd->sd_lock);
497 return 0;
498 }
499
500 static inline u32 round_up_to_quad(u32 i)
501 {
502 return (i + 3 ) & ~3;
503 }
504
505 static inline int
506 svc_safe_getnetobj(struct kvec *argv, struct xdr_netobj *o)
507 {
508 int l;
509
510 if (argv->iov_len < 4)
511 return -1;
512 o->len = ntohl(svc_getu32(argv));
513 l = round_up_to_quad(o->len);
514 if (argv->iov_len < l)
515 return -1;
516 o->data = argv->iov_base;
517 argv->iov_base += l;
518 argv->iov_len -= l;
519 return 0;
520 }
521
522 static inline int
523 svc_safe_putnetobj(struct kvec *resv, struct xdr_netobj *o)
524 {
525 u32 *p;
526
527 if (resv->iov_len + 4 > PAGE_SIZE)
528 return -1;
529 svc_putu32(resv, htonl(o->len));
530 p = resv->iov_base + resv->iov_len;
531 resv->iov_len += round_up_to_quad(o->len);
532 if (resv->iov_len > PAGE_SIZE)
533 return -1;
534 memcpy(p, o->data, o->len);
535 memset((u8 *)p + o->len, 0, round_up_to_quad(o->len) - o->len);
536 return 0;
537 }
538
539 /* Verify the checksum on the header and return SVC_OK on success.
540 * Otherwise, return SVC_DROP (in the case of a bad sequence number)
541 * or return SVC_DENIED and indicate error in authp.
542 */
543 static int
544 gss_verify_header(struct svc_rqst *rqstp, struct rsc *rsci,
545 u32 *rpcstart, struct rpc_gss_wire_cred *gc, u32 *authp)
546 {
547 struct gss_ctx *ctx_id = rsci->mechctx;
548 struct xdr_buf rpchdr;
549 struct xdr_netobj checksum;
550 u32 flavor = 0;
551 struct kvec *argv = &rqstp->rq_arg.head[0];
552 struct kvec iov;
553
554 /* data to compute the checksum over: */
555 iov.iov_base = rpcstart;
556 iov.iov_len = (u8 *)argv->iov_base - (u8 *)rpcstart;
557 xdr_buf_from_iov(&iov, &rpchdr);
558
559 *authp = rpc_autherr_badverf;
560 if (argv->iov_len < 4)
561 return SVC_DENIED;
562 flavor = ntohl(svc_getu32(argv));
563 if (flavor != RPC_AUTH_GSS)
564 return SVC_DENIED;
565 if (svc_safe_getnetobj(argv, &checksum))
566 return SVC_DENIED;
567
568 if (rqstp->rq_deferred) /* skip verification of revisited request */
569 return SVC_OK;
570 if (gss_verify_mic(ctx_id, &rpchdr, &checksum, NULL)
571 != GSS_S_COMPLETE) {
572 *authp = rpcsec_gsserr_credproblem;
573 return SVC_DENIED;
574 }
575
576 if (gc->gc_seq > MAXSEQ) {
577 dprintk("RPC: svcauth_gss: discarding request with large sequence number %d\n",
578 gc->gc_seq);
579 *authp = rpcsec_gsserr_ctxproblem;
580 return SVC_DENIED;
581 }
582 if (!gss_check_seq_num(rsci, gc->gc_seq)) {
583 dprintk("RPC: svcauth_gss: discarding request with old sequence number %d\n",
584 gc->gc_seq);
585 return SVC_DROP;
586 }
587 return SVC_OK;
588 }
589
590 static int
591 gss_write_verf(struct svc_rqst *rqstp, struct gss_ctx *ctx_id, u32 seq)
592 {
593 u32 xdr_seq;
594 u32 maj_stat;
595 struct xdr_buf verf_data;
596 struct xdr_netobj mic;
597 u32 *p;
598 struct kvec iov;
599
600 svc_putu32(rqstp->rq_res.head, htonl(RPC_AUTH_GSS));
601 xdr_seq = htonl(seq);
602
603 iov.iov_base = &xdr_seq;
604 iov.iov_len = sizeof(xdr_seq);
605 xdr_buf_from_iov(&iov, &verf_data);
606 p = rqstp->rq_res.head->iov_base + rqstp->rq_res.head->iov_len;
607 mic.data = (u8 *)(p + 1);
608 maj_stat = gss_get_mic(ctx_id, 0, &verf_data, &mic);
609 if (maj_stat != GSS_S_COMPLETE)
610 return -1;
611 *p++ = htonl(mic.len);
612 memset((u8 *)p + mic.len, 0, round_up_to_quad(mic.len) - mic.len);
613 p += XDR_QUADLEN(mic.len);
614 if (!xdr_ressize_check(rqstp, p))
615 return -1;
616 return 0;
617 }
618
619 struct gss_domain {
620 struct auth_domain h;
621 u32 pseudoflavor;
622 };
623
624 static struct auth_domain *
625 find_gss_auth_domain(struct gss_ctx *ctx, u32 svc)
626 {
627 char *name;
628
629 name = gss_service_to_auth_domain_name(ctx->mech_type, svc);
630 if (!name)
631 return NULL;
632 return auth_domain_find(name);
633 }
634
635 int
636 svcauth_gss_register_pseudoflavor(u32 pseudoflavor, char * name)
637 {
638 struct gss_domain *new;
639 struct auth_domain *test;
640 int stat = -ENOMEM;
641
642 new = kmalloc(sizeof(*new), GFP_KERNEL);
643 if (!new)
644 goto out;
645 cache_init(&new->h.h);
646 new->h.name = kmalloc(strlen(name) + 1, GFP_KERNEL);
647 if (!new->h.name)
648 goto out_free_dom;
649 strcpy(new->h.name, name);
650 new->h.flavour = RPC_AUTH_GSS;
651 new->pseudoflavor = pseudoflavor;
652 new->h.h.expiry_time = NEVER;
653
654 test = auth_domain_lookup(&new->h, 1);
655 if (test == &new->h) {
656 BUG_ON(atomic_dec_and_test(&new->h.h.refcnt));
657 } else { /* XXX Duplicate registration? */
658 auth_domain_put(&new->h);
659 goto out;
660 }
661 return 0;
662
663 out_free_dom:
664 kfree(new);
665 out:
666 return stat;
667 }
668
669 EXPORT_SYMBOL(svcauth_gss_register_pseudoflavor);
670
671 static inline int
672 read_u32_from_xdr_buf(struct xdr_buf *buf, int base, u32 *obj)
673 {
674 u32 raw;
675 int status;
676
677 status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
678 if (status)
679 return status;
680 *obj = ntohl(raw);
681 return 0;
682 }
683
684 /* It would be nice if this bit of code could be shared with the client.
685 * Obstacles:
686 * The client shouldn't malloc(), would have to pass in own memory.
687 * The server uses base of head iovec as read pointer, while the
688 * client uses separate pointer. */
689 static int
690 unwrap_integ_data(struct xdr_buf *buf, u32 seq, struct gss_ctx *ctx)
691 {
692 int stat = -EINVAL;
693 u32 integ_len, maj_stat;
694 struct xdr_netobj mic;
695 struct xdr_buf integ_buf;
696
697 integ_len = ntohl(svc_getu32(&buf->head[0]));
698 if (integ_len & 3)
699 goto out;
700 if (integ_len > buf->len)
701 goto out;
702 if (xdr_buf_subsegment(buf, &integ_buf, 0, integ_len))
703 BUG();
704 /* copy out mic... */
705 if (read_u32_from_xdr_buf(buf, integ_len, &mic.len))
706 BUG();
707 if (mic.len > RPC_MAX_AUTH_SIZE)
708 goto out;
709 mic.data = kmalloc(mic.len, GFP_KERNEL);
710 if (!mic.data)
711 goto out;
712 if (read_bytes_from_xdr_buf(buf, integ_len + 4, mic.data, mic.len))
713 goto out;
714 maj_stat = gss_verify_mic(ctx, &integ_buf, &mic, NULL);
715 if (maj_stat != GSS_S_COMPLETE)
716 goto out;
717 if (ntohl(svc_getu32(&buf->head[0])) != seq)
718 goto out;
719 stat = 0;
720 out:
721 return stat;
722 }
723
724 struct gss_svc_data {
725 /* decoded gss client cred: */
726 struct rpc_gss_wire_cred clcred;
727 /* pointer to the beginning of the procedure-specific results,
728 * which may be encrypted/checksummed in svcauth_gss_release: */
729 u32 *body_start;
730 struct rsc *rsci;
731 };
732
733 /*
734 * Accept an rpcsec packet.
735 * If context establishment, punt to user space
736 * If data exchange, verify/decrypt
737 * If context destruction, handle here
738 * In the context establishment and destruction case we encode
739 * response here and return SVC_COMPLETE.
740 */
741 static int
742 svcauth_gss_accept(struct svc_rqst *rqstp, u32 *authp)
743 {
744 struct kvec *argv = &rqstp->rq_arg.head[0];
745 struct kvec *resv = &rqstp->rq_res.head[0];
746 u32 crlen;
747 struct xdr_netobj tmpobj;
748 struct gss_svc_data *svcdata = rqstp->rq_auth_data;
749 struct rpc_gss_wire_cred *gc;
750 struct rsc *rsci = NULL;
751 struct rsi *rsip, rsikey;
752 u32 *rpcstart;
753 u32 *reject_stat = resv->iov_base + resv->iov_len;
754 int ret;
755
756 dprintk("RPC: svcauth_gss: argv->iov_len = %zd\n",argv->iov_len);
757
758 *authp = rpc_autherr_badcred;
759 if (!svcdata)
760 svcdata = kmalloc(sizeof(*svcdata), GFP_KERNEL);
761 if (!svcdata)
762 goto auth_err;
763 rqstp->rq_auth_data = svcdata;
764 svcdata->body_start = NULL;
765 svcdata->rsci = NULL;
766 gc = &svcdata->clcred;
767
768 /* start of rpc packet is 7 u32's back from here:
769 * xid direction rpcversion prog vers proc flavour
770 */
771 rpcstart = argv->iov_base;
772 rpcstart -= 7;
773
774 /* credential is:
775 * version(==1), proc(0,1,2,3), seq, service (1,2,3), handle
776 * at least 5 u32s, and is preceeded by length, so that makes 6.
777 */
778
779 if (argv->iov_len < 5 * 4)
780 goto auth_err;
781 crlen = ntohl(svc_getu32(argv));
782 if (ntohl(svc_getu32(argv)) != RPC_GSS_VERSION)
783 goto auth_err;
784 gc->gc_proc = ntohl(svc_getu32(argv));
785 gc->gc_seq = ntohl(svc_getu32(argv));
786 gc->gc_svc = ntohl(svc_getu32(argv));
787 if (svc_safe_getnetobj(argv, &gc->gc_ctx))
788 goto auth_err;
789 if (crlen != round_up_to_quad(gc->gc_ctx.len) + 5 * 4)
790 goto auth_err;
791
792 if ((gc->gc_proc != RPC_GSS_PROC_DATA) && (rqstp->rq_proc != 0))
793 goto auth_err;
794
795 /*
796 * We've successfully parsed the credential. Let's check out the
797 * verifier. An AUTH_NULL verifier is allowed (and required) for
798 * INIT and CONTINUE_INIT requests. AUTH_RPCSEC_GSS is required for
799 * PROC_DATA and PROC_DESTROY.
800 *
801 * AUTH_NULL verifier is 0 (AUTH_NULL), 0 (length).
802 * AUTH_RPCSEC_GSS verifier is:
803 * 6 (AUTH_RPCSEC_GSS), length, checksum.
804 * checksum is calculated over rpcheader from xid up to here.
805 */
806 *authp = rpc_autherr_badverf;
807 switch (gc->gc_proc) {
808 case RPC_GSS_PROC_INIT:
809 case RPC_GSS_PROC_CONTINUE_INIT:
810 if (argv->iov_len < 2 * 4)
811 goto auth_err;
812 if (ntohl(svc_getu32(argv)) != RPC_AUTH_NULL)
813 goto auth_err;
814 if (ntohl(svc_getu32(argv)) != 0)
815 goto auth_err;
816 break;
817 case RPC_GSS_PROC_DATA:
818 case RPC_GSS_PROC_DESTROY:
819 *authp = rpcsec_gsserr_credproblem;
820 rsci = gss_svc_searchbyctx(&gc->gc_ctx);
821 if (!rsci)
822 goto auth_err;
823 switch (gss_verify_header(rqstp, rsci, rpcstart, gc, authp)) {
824 case SVC_OK:
825 break;
826 case SVC_DENIED:
827 goto auth_err;
828 case SVC_DROP:
829 goto drop;
830 }
831 break;
832 default:
833 *authp = rpc_autherr_rejectedcred;
834 goto auth_err;
835 }
836
837 /* now act upon the command: */
838 switch (gc->gc_proc) {
839 case RPC_GSS_PROC_INIT:
840 case RPC_GSS_PROC_CONTINUE_INIT:
841 *authp = rpc_autherr_badcred;
842 if (gc->gc_proc == RPC_GSS_PROC_INIT && gc->gc_ctx.len != 0)
843 goto auth_err;
844 memset(&rsikey, 0, sizeof(rsikey));
845 if (dup_netobj(&rsikey.in_handle, &gc->gc_ctx))
846 goto drop;
847 *authp = rpc_autherr_badverf;
848 if (svc_safe_getnetobj(argv, &tmpobj)) {
849 kfree(rsikey.in_handle.data);
850 goto auth_err;
851 }
852 if (dup_netobj(&rsikey.in_token, &tmpobj)) {
853 kfree(rsikey.in_handle.data);
854 goto drop;
855 }
856
857 rsip = rsi_lookup(&rsikey, 0);
858 rsi_free(&rsikey);
859 if (!rsip) {
860 goto drop;
861 }
862 switch(cache_check(&rsi_cache, &rsip->h, &rqstp->rq_chandle)) {
863 case -EAGAIN:
864 goto drop;
865 case -ENOENT:
866 goto drop;
867 case 0:
868 rsci = gss_svc_searchbyctx(&rsip->out_handle);
869 if (!rsci) {
870 goto drop;
871 }
872 if (gss_write_verf(rqstp, rsci->mechctx, GSS_SEQ_WIN))
873 goto drop;
874 if (resv->iov_len + 4 > PAGE_SIZE)
875 goto drop;
876 svc_putu32(resv, rpc_success);
877 if (svc_safe_putnetobj(resv, &rsip->out_handle))
878 goto drop;
879 if (resv->iov_len + 3 * 4 > PAGE_SIZE)
880 goto drop;
881 svc_putu32(resv, htonl(rsip->major_status));
882 svc_putu32(resv, htonl(rsip->minor_status));
883 svc_putu32(resv, htonl(GSS_SEQ_WIN));
884 if (svc_safe_putnetobj(resv, &rsip->out_token))
885 goto drop;
886 rqstp->rq_client = NULL;
887 }
888 goto complete;
889 case RPC_GSS_PROC_DESTROY:
890 set_bit(CACHE_NEGATIVE, &rsci->h.flags);
891 if (resv->iov_len + 4 > PAGE_SIZE)
892 goto drop;
893 svc_putu32(resv, rpc_success);
894 goto complete;
895 case RPC_GSS_PROC_DATA:
896 *authp = rpc_autherr_badcred;
897 rqstp->rq_client =
898 find_gss_auth_domain(rsci->mechctx, gc->gc_svc);
899 if (rqstp->rq_client == NULL)
900 goto auth_err;
901 *authp = rpcsec_gsserr_ctxproblem;
902 if (gss_write_verf(rqstp, rsci->mechctx, gc->gc_seq))
903 goto auth_err;
904 rqstp->rq_cred = rsci->cred;
905 get_group_info(rsci->cred.cr_group_info);
906 *authp = rpc_autherr_badcred;
907 switch (gc->gc_svc) {
908 case RPC_GSS_SVC_NONE:
909 break;
910 case RPC_GSS_SVC_INTEGRITY:
911 if (unwrap_integ_data(&rqstp->rq_arg,
912 gc->gc_seq, rsci->mechctx))
913 goto auth_err;
914 svcdata->rsci = rsci;
915 cache_get(&rsci->h);
916 /* placeholders for length and seq. number: */
917 svcdata->body_start = resv->iov_base + resv->iov_len;
918 svc_putu32(resv, 0);
919 svc_putu32(resv, 0);
920 break;
921 case RPC_GSS_SVC_PRIVACY:
922 /* currently unsupported */
923 default:
924 goto auth_err;
925 }
926 ret = SVC_OK;
927 goto out;
928 }
929 auth_err:
930 /* Restore write pointer to original value: */
931 xdr_ressize_check(rqstp, reject_stat);
932 ret = SVC_DENIED;
933 goto out;
934 complete:
935 ret = SVC_COMPLETE;
936 goto out;
937 drop:
938 ret = SVC_DROP;
939 out:
940 if (rsci)
941 rsc_put(&rsci->h, &rsc_cache);
942 return ret;
943 }
944
945 static int
946 svcauth_gss_release(struct svc_rqst *rqstp)
947 {
948 struct gss_svc_data *gsd = (struct gss_svc_data *)rqstp->rq_auth_data;
949 struct rpc_gss_wire_cred *gc = &gsd->clcred;
950 struct xdr_buf *resbuf = &rqstp->rq_res;
951 struct xdr_buf integ_buf;
952 struct xdr_netobj mic;
953 struct kvec *resv;
954 u32 *p;
955 int integ_offset, integ_len;
956 int stat = -EINVAL;
957
958 if (gc->gc_proc != RPC_GSS_PROC_DATA)
959 goto out;
960 /* Release can be called twice, but we only wrap once. */
961 if (gsd->body_start == NULL)
962 goto out;
963 /* normally not set till svc_send, but we need it here: */
964 resbuf->len = resbuf->head[0].iov_len
965 + resbuf->page_len + resbuf->tail[0].iov_len;
966 switch (gc->gc_svc) {
967 case RPC_GSS_SVC_NONE:
968 break;
969 case RPC_GSS_SVC_INTEGRITY:
970 p = gsd->body_start;
971 gsd->body_start = NULL;
972 /* move accept_stat to right place: */
973 memcpy(p, p + 2, 4);
974 /* don't wrap in failure case: */
975 /* Note: counting on not getting here if call was not even
976 * accepted! */
977 if (*p != rpc_success) {
978 resbuf->head[0].iov_len -= 2 * 4;
979 goto out;
980 }
981 p++;
982 integ_offset = (u8 *)(p + 1) - (u8 *)resbuf->head[0].iov_base;
983 integ_len = resbuf->len - integ_offset;
984 BUG_ON(integ_len % 4);
985 *p++ = htonl(integ_len);
986 *p++ = htonl(gc->gc_seq);
987 if (xdr_buf_subsegment(resbuf, &integ_buf, integ_offset,
988 integ_len))
989 BUG();
990 if (resbuf->page_len == 0
991 && resbuf->tail[0].iov_len + RPC_MAX_AUTH_SIZE
992 < PAGE_SIZE) {
993 BUG_ON(resbuf->tail[0].iov_len);
994 /* Use head for everything */
995 resv = &resbuf->head[0];
996 } else if (resbuf->tail[0].iov_base == NULL) {
997 /* copied from nfsd4_encode_read */
998 svc_take_page(rqstp);
999 resbuf->tail[0].iov_base = page_address(rqstp
1000 ->rq_respages[rqstp->rq_resused-1]);
1001 rqstp->rq_restailpage = rqstp->rq_resused-1;
1002 resbuf->tail[0].iov_len = 0;
1003 resv = &resbuf->tail[0];
1004 } else {
1005 resv = &resbuf->tail[0];
1006 }
1007 mic.data = (u8 *)resv->iov_base + resv->iov_len + 4;
1008 if (gss_get_mic(gsd->rsci->mechctx, 0, &integ_buf, &mic))
1009 goto out_err;
1010 svc_putu32(resv, htonl(mic.len));
1011 memset(mic.data + mic.len, 0,
1012 round_up_to_quad(mic.len) - mic.len);
1013 resv->iov_len += XDR_QUADLEN(mic.len) << 2;
1014 /* not strictly required: */
1015 resbuf->len += XDR_QUADLEN(mic.len) << 2;
1016 BUG_ON(resv->iov_len > PAGE_SIZE);
1017 break;
1018 case RPC_GSS_SVC_PRIVACY:
1019 default:
1020 goto out_err;
1021 }
1022
1023 out:
1024 stat = 0;
1025 out_err:
1026 if (rqstp->rq_client)
1027 auth_domain_put(rqstp->rq_client);
1028 rqstp->rq_client = NULL;
1029 if (rqstp->rq_cred.cr_group_info)
1030 put_group_info(rqstp->rq_cred.cr_group_info);
1031 rqstp->rq_cred.cr_group_info = NULL;
1032 if (gsd->rsci)
1033 rsc_put(&gsd->rsci->h, &rsc_cache);
1034 gsd->rsci = NULL;
1035
1036 return stat;
1037 }
1038
1039 static void
1040 svcauth_gss_domain_release(struct auth_domain *dom)
1041 {
1042 struct gss_domain *gd = container_of(dom, struct gss_domain, h);
1043
1044 kfree(dom->name);
1045 kfree(gd);
1046 }
1047
1048 static struct auth_ops svcauthops_gss = {
1049 .name = "rpcsec_gss",
1050 .owner = THIS_MODULE,
1051 .flavour = RPC_AUTH_GSS,
1052 .accept = svcauth_gss_accept,
1053 .release = svcauth_gss_release,
1054 .domain_release = svcauth_gss_domain_release,
1055 };
1056
1057 int
1058 gss_svc_init(void)
1059 {
1060 int rv = svc_auth_register(RPC_AUTH_GSS, &svcauthops_gss);
1061 if (rv == 0) {
1062 cache_register(&rsc_cache);
1063 cache_register(&rsi_cache);
1064 }
1065 return rv;
1066 }
1067
1068 void
1069 gss_svc_shutdown(void)
1070 {
1071 cache_unregister(&rsc_cache);
1072 cache_unregister(&rsi_cache);
1073 svc_auth_unregister(RPC_AUTH_GSS);
1074 }
1075
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