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Linux/net/sunrpc/auth_gss/svcauth_gss.c

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  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/slab.h>
 41 #include <linux/types.h>
 42 #include <linux/module.h>
 43 #include <linux/pagemap.h>
 44 #include <linux/user_namespace.h>
 45 
 46 #include <linux/sunrpc/auth_gss.h>
 47 #include <linux/sunrpc/gss_err.h>
 48 #include <linux/sunrpc/svcauth.h>
 49 #include <linux/sunrpc/svcauth_gss.h>
 50 #include <linux/sunrpc/cache.h>
 51 #include "gss_rpc_upcall.h"
 52 
 53 
 54 #ifdef RPC_DEBUG
 55 # define RPCDBG_FACILITY        RPCDBG_AUTH
 56 #endif
 57 
 58 /* The rpcsec_init cache is used for mapping RPCSEC_GSS_{,CONT_}INIT requests
 59  * into replies.
 60  *
 61  * Key is context handle (\x if empty) and gss_token.
 62  * Content is major_status minor_status (integers) context_handle, reply_token.
 63  *
 64  */
 65 
 66 static int netobj_equal(struct xdr_netobj *a, struct xdr_netobj *b)
 67 {
 68         return a->len == b->len && 0 == memcmp(a->data, b->data, a->len);
 69 }
 70 
 71 #define RSI_HASHBITS    6
 72 #define RSI_HASHMAX     (1<<RSI_HASHBITS)
 73 
 74 struct rsi {
 75         struct cache_head       h;
 76         struct xdr_netobj       in_handle, in_token;
 77         struct xdr_netobj       out_handle, out_token;
 78         int                     major_status, minor_status;
 79 };
 80 
 81 static struct rsi *rsi_update(struct cache_detail *cd, struct rsi *new, struct rsi *old);
 82 static struct rsi *rsi_lookup(struct cache_detail *cd, struct rsi *item);
 83 
 84 static void rsi_free(struct rsi *rsii)
 85 {
 86         kfree(rsii->in_handle.data);
 87         kfree(rsii->in_token.data);
 88         kfree(rsii->out_handle.data);
 89         kfree(rsii->out_token.data);
 90 }
 91 
 92 static void rsi_put(struct kref *ref)
 93 {
 94         struct rsi *rsii = container_of(ref, struct rsi, h.ref);
 95         rsi_free(rsii);
 96         kfree(rsii);
 97 }
 98 
 99 static inline int rsi_hash(struct rsi *item)
100 {
101         return hash_mem(item->in_handle.data, item->in_handle.len, RSI_HASHBITS)
102              ^ hash_mem(item->in_token.data, item->in_token.len, RSI_HASHBITS);
103 }
104 
105 static int rsi_match(struct cache_head *a, struct cache_head *b)
106 {
107         struct rsi *item = container_of(a, struct rsi, h);
108         struct rsi *tmp = container_of(b, struct rsi, h);
109         return netobj_equal(&item->in_handle, &tmp->in_handle) &&
110                netobj_equal(&item->in_token, &tmp->in_token);
111 }
112 
113 static int dup_to_netobj(struct xdr_netobj *dst, char *src, int len)
114 {
115         dst->len = len;
116         dst->data = (len ? kmemdup(src, len, GFP_KERNEL) : NULL);
117         if (len && !dst->data)
118                 return -ENOMEM;
119         return 0;
120 }
121 
122 static inline int dup_netobj(struct xdr_netobj *dst, struct xdr_netobj *src)
123 {
124         return dup_to_netobj(dst, src->data, src->len);
125 }
126 
127 static void rsi_init(struct cache_head *cnew, struct cache_head *citem)
128 {
129         struct rsi *new = container_of(cnew, struct rsi, h);
130         struct rsi *item = container_of(citem, struct rsi, h);
131 
132         new->out_handle.data = NULL;
133         new->out_handle.len = 0;
134         new->out_token.data = NULL;
135         new->out_token.len = 0;
136         new->in_handle.len = item->in_handle.len;
137         item->in_handle.len = 0;
138         new->in_token.len = item->in_token.len;
139         item->in_token.len = 0;
140         new->in_handle.data = item->in_handle.data;
141         item->in_handle.data = NULL;
142         new->in_token.data = item->in_token.data;
143         item->in_token.data = NULL;
144 }
145 
146 static void update_rsi(struct cache_head *cnew, struct cache_head *citem)
147 {
148         struct rsi *new = container_of(cnew, struct rsi, h);
149         struct rsi *item = container_of(citem, struct rsi, h);
150 
151         BUG_ON(new->out_handle.data || new->out_token.data);
152         new->out_handle.len = item->out_handle.len;
153         item->out_handle.len = 0;
154         new->out_token.len = item->out_token.len;
155         item->out_token.len = 0;
156         new->out_handle.data = item->out_handle.data;
157         item->out_handle.data = NULL;
158         new->out_token.data = item->out_token.data;
159         item->out_token.data = NULL;
160 
161         new->major_status = item->major_status;
162         new->minor_status = item->minor_status;
163 }
164 
165 static struct cache_head *rsi_alloc(void)
166 {
167         struct rsi *rsii = kmalloc(sizeof(*rsii), GFP_KERNEL);
168         if (rsii)
169                 return &rsii->h;
170         else
171                 return NULL;
172 }
173 
174 static void rsi_request(struct cache_detail *cd,
175                        struct cache_head *h,
176                        char **bpp, int *blen)
177 {
178         struct rsi *rsii = container_of(h, struct rsi, h);
179 
180         qword_addhex(bpp, blen, rsii->in_handle.data, rsii->in_handle.len);
181         qword_addhex(bpp, blen, rsii->in_token.data, rsii->in_token.len);
182         (*bpp)[-1] = '\n';
183 }
184 
185 static int rsi_parse(struct cache_detail *cd,
186                     char *mesg, int mlen)
187 {
188         /* context token expiry major minor context token */
189         char *buf = mesg;
190         char *ep;
191         int len;
192         struct rsi rsii, *rsip = NULL;
193         time_t expiry;
194         int status = -EINVAL;
195 
196         memset(&rsii, 0, sizeof(rsii));
197         /* handle */
198         len = qword_get(&mesg, buf, mlen);
199         if (len < 0)
200                 goto out;
201         status = -ENOMEM;
202         if (dup_to_netobj(&rsii.in_handle, buf, len))
203                 goto out;
204 
205         /* token */
206         len = qword_get(&mesg, buf, mlen);
207         status = -EINVAL;
208         if (len < 0)
209                 goto out;
210         status = -ENOMEM;
211         if (dup_to_netobj(&rsii.in_token, buf, len))
212                 goto out;
213 
214         rsip = rsi_lookup(cd, &rsii);
215         if (!rsip)
216                 goto out;
217 
218         rsii.h.flags = 0;
219         /* expiry */
220         expiry = get_expiry(&mesg);
221         status = -EINVAL;
222         if (expiry == 0)
223                 goto out;
224 
225         /* major/minor */
226         len = qword_get(&mesg, buf, mlen);
227         if (len <= 0)
228                 goto out;
229         rsii.major_status = simple_strtoul(buf, &ep, 10);
230         if (*ep)
231                 goto out;
232         len = qword_get(&mesg, buf, mlen);
233         if (len <= 0)
234                 goto out;
235         rsii.minor_status = simple_strtoul(buf, &ep, 10);
236         if (*ep)
237                 goto out;
238 
239         /* out_handle */
240         len = qword_get(&mesg, buf, mlen);
241         if (len < 0)
242                 goto out;
243         status = -ENOMEM;
244         if (dup_to_netobj(&rsii.out_handle, buf, len))
245                 goto out;
246 
247         /* out_token */
248         len = qword_get(&mesg, buf, mlen);
249         status = -EINVAL;
250         if (len < 0)
251                 goto out;
252         status = -ENOMEM;
253         if (dup_to_netobj(&rsii.out_token, buf, len))
254                 goto out;
255         rsii.h.expiry_time = expiry;
256         rsip = rsi_update(cd, &rsii, rsip);
257         status = 0;
258 out:
259         rsi_free(&rsii);
260         if (rsip)
261                 cache_put(&rsip->h, cd);
262         else
263                 status = -ENOMEM;
264         return status;
265 }
266 
267 static struct cache_detail rsi_cache_template = {
268         .owner          = THIS_MODULE,
269         .hash_size      = RSI_HASHMAX,
270         .name           = "auth.rpcsec.init",
271         .cache_put      = rsi_put,
272         .cache_request  = rsi_request,
273         .cache_parse    = rsi_parse,
274         .match          = rsi_match,
275         .init           = rsi_init,
276         .update         = update_rsi,
277         .alloc          = rsi_alloc,
278 };
279 
280 static struct rsi *rsi_lookup(struct cache_detail *cd, struct rsi *item)
281 {
282         struct cache_head *ch;
283         int hash = rsi_hash(item);
284 
285         ch = sunrpc_cache_lookup(cd, &item->h, hash);
286         if (ch)
287                 return container_of(ch, struct rsi, h);
288         else
289                 return NULL;
290 }
291 
292 static struct rsi *rsi_update(struct cache_detail *cd, struct rsi *new, struct rsi *old)
293 {
294         struct cache_head *ch;
295         int hash = rsi_hash(new);
296 
297         ch = sunrpc_cache_update(cd, &new->h,
298                                  &old->h, hash);
299         if (ch)
300                 return container_of(ch, struct rsi, h);
301         else
302                 return NULL;
303 }
304 
305 
306 /*
307  * The rpcsec_context cache is used to store a context that is
308  * used in data exchange.
309  * The key is a context handle. The content is:
310  *  uid, gidlist, mechanism, service-set, mech-specific-data
311  */
312 
313 #define RSC_HASHBITS    10
314 #define RSC_HASHMAX     (1<<RSC_HASHBITS)
315 
316 #define GSS_SEQ_WIN     128
317 
318 struct gss_svc_seq_data {
319         /* highest seq number seen so far: */
320         int                     sd_max;
321         /* for i such that sd_max-GSS_SEQ_WIN < i <= sd_max, the i-th bit of
322          * sd_win is nonzero iff sequence number i has been seen already: */
323         unsigned long           sd_win[GSS_SEQ_WIN/BITS_PER_LONG];
324         spinlock_t              sd_lock;
325 };
326 
327 struct rsc {
328         struct cache_head       h;
329         struct xdr_netobj       handle;
330         struct svc_cred         cred;
331         struct gss_svc_seq_data seqdata;
332         struct gss_ctx          *mechctx;
333 };
334 
335 static struct rsc *rsc_update(struct cache_detail *cd, struct rsc *new, struct rsc *old);
336 static struct rsc *rsc_lookup(struct cache_detail *cd, struct rsc *item);
337 
338 static void rsc_free(struct rsc *rsci)
339 {
340         kfree(rsci->handle.data);
341         if (rsci->mechctx)
342                 gss_delete_sec_context(&rsci->mechctx);
343         free_svc_cred(&rsci->cred);
344 }
345 
346 static void rsc_put(struct kref *ref)
347 {
348         struct rsc *rsci = container_of(ref, struct rsc, h.ref);
349 
350         rsc_free(rsci);
351         kfree(rsci);
352 }
353 
354 static inline int
355 rsc_hash(struct rsc *rsci)
356 {
357         return hash_mem(rsci->handle.data, rsci->handle.len, RSC_HASHBITS);
358 }
359 
360 static int
361 rsc_match(struct cache_head *a, struct cache_head *b)
362 {
363         struct rsc *new = container_of(a, struct rsc, h);
364         struct rsc *tmp = container_of(b, struct rsc, h);
365 
366         return netobj_equal(&new->handle, &tmp->handle);
367 }
368 
369 static void
370 rsc_init(struct cache_head *cnew, struct cache_head *ctmp)
371 {
372         struct rsc *new = container_of(cnew, struct rsc, h);
373         struct rsc *tmp = container_of(ctmp, struct rsc, h);
374 
375         new->handle.len = tmp->handle.len;
376         tmp->handle.len = 0;
377         new->handle.data = tmp->handle.data;
378         tmp->handle.data = NULL;
379         new->mechctx = NULL;
380         new->cred.cr_group_info = NULL;
381         new->cred.cr_principal = NULL;
382 }
383 
384 static void
385 update_rsc(struct cache_head *cnew, struct cache_head *ctmp)
386 {
387         struct rsc *new = container_of(cnew, struct rsc, h);
388         struct rsc *tmp = container_of(ctmp, struct rsc, h);
389 
390         new->mechctx = tmp->mechctx;
391         tmp->mechctx = NULL;
392         memset(&new->seqdata, 0, sizeof(new->seqdata));
393         spin_lock_init(&new->seqdata.sd_lock);
394         new->cred = tmp->cred;
395         tmp->cred.cr_group_info = NULL;
396         new->cred.cr_principal = tmp->cred.cr_principal;
397         tmp->cred.cr_principal = NULL;
398 }
399 
400 static struct cache_head *
401 rsc_alloc(void)
402 {
403         struct rsc *rsci = kmalloc(sizeof(*rsci), GFP_KERNEL);
404         if (rsci)
405                 return &rsci->h;
406         else
407                 return NULL;
408 }
409 
410 static int rsc_parse(struct cache_detail *cd,
411                      char *mesg, int mlen)
412 {
413         /* contexthandle expiry [ uid gid N <n gids> mechname ...mechdata... ] */
414         char *buf = mesg;
415         int id;
416         int len, rv;
417         struct rsc rsci, *rscp = NULL;
418         time_t expiry;
419         int status = -EINVAL;
420         struct gss_api_mech *gm = NULL;
421 
422         memset(&rsci, 0, sizeof(rsci));
423         /* context handle */
424         len = qword_get(&mesg, buf, mlen);
425         if (len < 0) goto out;
426         status = -ENOMEM;
427         if (dup_to_netobj(&rsci.handle, buf, len))
428                 goto out;
429 
430         rsci.h.flags = 0;
431         /* expiry */
432         expiry = get_expiry(&mesg);
433         status = -EINVAL;
434         if (expiry == 0)
435                 goto out;
436 
437         rscp = rsc_lookup(cd, &rsci);
438         if (!rscp)
439                 goto out;
440 
441         /* uid, or NEGATIVE */
442         rv = get_int(&mesg, &id);
443         if (rv == -EINVAL)
444                 goto out;
445         if (rv == -ENOENT)
446                 set_bit(CACHE_NEGATIVE, &rsci.h.flags);
447         else {
448                 int N, i;
449 
450                 /*
451                  * NOTE: we skip uid_valid()/gid_valid() checks here:
452                  * instead, * -1 id's are later mapped to the
453                  * (export-specific) anonymous id by nfsd_setuser.
454                  *
455                  * (But supplementary gid's get no such special
456                  * treatment so are checked for validity here.)
457                  */
458                 /* uid */
459                 rsci.cred.cr_uid = make_kuid(&init_user_ns, id);
460 
461                 /* gid */
462                 if (get_int(&mesg, &id))
463                         goto out;
464                 rsci.cred.cr_gid = make_kgid(&init_user_ns, id);
465 
466                 /* number of additional gid's */
467                 if (get_int(&mesg, &N))
468                         goto out;
469                 status = -ENOMEM;
470                 rsci.cred.cr_group_info = groups_alloc(N);
471                 if (rsci.cred.cr_group_info == NULL)
472                         goto out;
473 
474                 /* gid's */
475                 status = -EINVAL;
476                 for (i=0; i<N; i++) {
477                         kgid_t kgid;
478                         if (get_int(&mesg, &id))
479                                 goto out;
480                         kgid = make_kgid(&init_user_ns, id);
481                         if (!gid_valid(kgid))
482                                 goto out;
483                         GROUP_AT(rsci.cred.cr_group_info, i) = kgid;
484                 }
485 
486                 /* mech name */
487                 len = qword_get(&mesg, buf, mlen);
488                 if (len < 0)
489                         goto out;
490                 gm = gss_mech_get_by_name(buf);
491                 status = -EOPNOTSUPP;
492                 if (!gm)
493                         goto out;
494 
495                 status = -EINVAL;
496                 /* mech-specific data: */
497                 len = qword_get(&mesg, buf, mlen);
498                 if (len < 0)
499                         goto out;
500                 status = gss_import_sec_context(buf, len, gm, &rsci.mechctx,
501                                                 NULL, GFP_KERNEL);
502                 if (status)
503                         goto out;
504 
505                 /* get client name */
506                 len = qword_get(&mesg, buf, mlen);
507                 if (len > 0) {
508                         rsci.cred.cr_principal = kstrdup(buf, GFP_KERNEL);
509                         if (!rsci.cred.cr_principal) {
510                                 status = -ENOMEM;
511                                 goto out;
512                         }
513                 }
514 
515         }
516         rsci.h.expiry_time = expiry;
517         rscp = rsc_update(cd, &rsci, rscp);
518         status = 0;
519 out:
520         gss_mech_put(gm);
521         rsc_free(&rsci);
522         if (rscp)
523                 cache_put(&rscp->h, cd);
524         else
525                 status = -ENOMEM;
526         return status;
527 }
528 
529 static struct cache_detail rsc_cache_template = {
530         .owner          = THIS_MODULE,
531         .hash_size      = RSC_HASHMAX,
532         .name           = "auth.rpcsec.context",
533         .cache_put      = rsc_put,
534         .cache_parse    = rsc_parse,
535         .match          = rsc_match,
536         .init           = rsc_init,
537         .update         = update_rsc,
538         .alloc          = rsc_alloc,
539 };
540 
541 static struct rsc *rsc_lookup(struct cache_detail *cd, struct rsc *item)
542 {
543         struct cache_head *ch;
544         int hash = rsc_hash(item);
545 
546         ch = sunrpc_cache_lookup(cd, &item->h, hash);
547         if (ch)
548                 return container_of(ch, struct rsc, h);
549         else
550                 return NULL;
551 }
552 
553 static struct rsc *rsc_update(struct cache_detail *cd, struct rsc *new, struct rsc *old)
554 {
555         struct cache_head *ch;
556         int hash = rsc_hash(new);
557 
558         ch = sunrpc_cache_update(cd, &new->h,
559                                  &old->h, hash);
560         if (ch)
561                 return container_of(ch, struct rsc, h);
562         else
563                 return NULL;
564 }
565 
566 
567 static struct rsc *
568 gss_svc_searchbyctx(struct cache_detail *cd, struct xdr_netobj *handle)
569 {
570         struct rsc rsci;
571         struct rsc *found;
572 
573         memset(&rsci, 0, sizeof(rsci));
574         if (dup_to_netobj(&rsci.handle, handle->data, handle->len))
575                 return NULL;
576         found = rsc_lookup(cd, &rsci);
577         rsc_free(&rsci);
578         if (!found)
579                 return NULL;
580         if (cache_check(cd, &found->h, NULL))
581                 return NULL;
582         return found;
583 }
584 
585 /* Implements sequence number algorithm as specified in RFC 2203. */
586 static int
587 gss_check_seq_num(struct rsc *rsci, int seq_num)
588 {
589         struct gss_svc_seq_data *sd = &rsci->seqdata;
590 
591         spin_lock(&sd->sd_lock);
592         if (seq_num > sd->sd_max) {
593                 if (seq_num >= sd->sd_max + GSS_SEQ_WIN) {
594                         memset(sd->sd_win,0,sizeof(sd->sd_win));
595                         sd->sd_max = seq_num;
596                 } else while (sd->sd_max < seq_num) {
597                         sd->sd_max++;
598                         __clear_bit(sd->sd_max % GSS_SEQ_WIN, sd->sd_win);
599                 }
600                 __set_bit(seq_num % GSS_SEQ_WIN, sd->sd_win);
601                 goto ok;
602         } else if (seq_num <= sd->sd_max - GSS_SEQ_WIN) {
603                 goto drop;
604         }
605         /* sd_max - GSS_SEQ_WIN < seq_num <= sd_max */
606         if (__test_and_set_bit(seq_num % GSS_SEQ_WIN, sd->sd_win))
607                 goto drop;
608 ok:
609         spin_unlock(&sd->sd_lock);
610         return 1;
611 drop:
612         spin_unlock(&sd->sd_lock);
613         return 0;
614 }
615 
616 static inline u32 round_up_to_quad(u32 i)
617 {
618         return (i + 3 ) & ~3;
619 }
620 
621 static inline int
622 svc_safe_getnetobj(struct kvec *argv, struct xdr_netobj *o)
623 {
624         int l;
625 
626         if (argv->iov_len < 4)
627                 return -1;
628         o->len = svc_getnl(argv);
629         l = round_up_to_quad(o->len);
630         if (argv->iov_len < l)
631                 return -1;
632         o->data = argv->iov_base;
633         argv->iov_base += l;
634         argv->iov_len -= l;
635         return 0;
636 }
637 
638 static inline int
639 svc_safe_putnetobj(struct kvec *resv, struct xdr_netobj *o)
640 {
641         u8 *p;
642 
643         if (resv->iov_len + 4 > PAGE_SIZE)
644                 return -1;
645         svc_putnl(resv, o->len);
646         p = resv->iov_base + resv->iov_len;
647         resv->iov_len += round_up_to_quad(o->len);
648         if (resv->iov_len > PAGE_SIZE)
649                 return -1;
650         memcpy(p, o->data, o->len);
651         memset(p + o->len, 0, round_up_to_quad(o->len) - o->len);
652         return 0;
653 }
654 
655 /*
656  * Verify the checksum on the header and return SVC_OK on success.
657  * Otherwise, return SVC_DROP (in the case of a bad sequence number)
658  * or return SVC_DENIED and indicate error in authp.
659  */
660 static int
661 gss_verify_header(struct svc_rqst *rqstp, struct rsc *rsci,
662                   __be32 *rpcstart, struct rpc_gss_wire_cred *gc, __be32 *authp)
663 {
664         struct gss_ctx          *ctx_id = rsci->mechctx;
665         struct xdr_buf          rpchdr;
666         struct xdr_netobj       checksum;
667         u32                     flavor = 0;
668         struct kvec             *argv = &rqstp->rq_arg.head[0];
669         struct kvec             iov;
670 
671         /* data to compute the checksum over: */
672         iov.iov_base = rpcstart;
673         iov.iov_len = (u8 *)argv->iov_base - (u8 *)rpcstart;
674         xdr_buf_from_iov(&iov, &rpchdr);
675 
676         *authp = rpc_autherr_badverf;
677         if (argv->iov_len < 4)
678                 return SVC_DENIED;
679         flavor = svc_getnl(argv);
680         if (flavor != RPC_AUTH_GSS)
681                 return SVC_DENIED;
682         if (svc_safe_getnetobj(argv, &checksum))
683                 return SVC_DENIED;
684 
685         if (rqstp->rq_deferred) /* skip verification of revisited request */
686                 return SVC_OK;
687         if (gss_verify_mic(ctx_id, &rpchdr, &checksum) != GSS_S_COMPLETE) {
688                 *authp = rpcsec_gsserr_credproblem;
689                 return SVC_DENIED;
690         }
691 
692         if (gc->gc_seq > MAXSEQ) {
693                 dprintk("RPC:       svcauth_gss: discarding request with "
694                                 "large sequence number %d\n", gc->gc_seq);
695                 *authp = rpcsec_gsserr_ctxproblem;
696                 return SVC_DENIED;
697         }
698         if (!gss_check_seq_num(rsci, gc->gc_seq)) {
699                 dprintk("RPC:       svcauth_gss: discarding request with "
700                                 "old sequence number %d\n", gc->gc_seq);
701                 return SVC_DROP;
702         }
703         return SVC_OK;
704 }
705 
706 static int
707 gss_write_null_verf(struct svc_rqst *rqstp)
708 {
709         __be32     *p;
710 
711         svc_putnl(rqstp->rq_res.head, RPC_AUTH_NULL);
712         p = rqstp->rq_res.head->iov_base + rqstp->rq_res.head->iov_len;
713         /* don't really need to check if head->iov_len > PAGE_SIZE ... */
714         *p++ = 0;
715         if (!xdr_ressize_check(rqstp, p))
716                 return -1;
717         return 0;
718 }
719 
720 static int
721 gss_write_verf(struct svc_rqst *rqstp, struct gss_ctx *ctx_id, u32 seq)
722 {
723         __be32                  xdr_seq;
724         u32                     maj_stat;
725         struct xdr_buf          verf_data;
726         struct xdr_netobj       mic;
727         __be32                  *p;
728         struct kvec             iov;
729 
730         svc_putnl(rqstp->rq_res.head, RPC_AUTH_GSS);
731         xdr_seq = htonl(seq);
732 
733         iov.iov_base = &xdr_seq;
734         iov.iov_len = sizeof(xdr_seq);
735         xdr_buf_from_iov(&iov, &verf_data);
736         p = rqstp->rq_res.head->iov_base + rqstp->rq_res.head->iov_len;
737         mic.data = (u8 *)(p + 1);
738         maj_stat = gss_get_mic(ctx_id, &verf_data, &mic);
739         if (maj_stat != GSS_S_COMPLETE)
740                 return -1;
741         *p++ = htonl(mic.len);
742         memset((u8 *)p + mic.len, 0, round_up_to_quad(mic.len) - mic.len);
743         p += XDR_QUADLEN(mic.len);
744         if (!xdr_ressize_check(rqstp, p))
745                 return -1;
746         return 0;
747 }
748 
749 struct gss_domain {
750         struct auth_domain      h;
751         u32                     pseudoflavor;
752 };
753 
754 static struct auth_domain *
755 find_gss_auth_domain(struct gss_ctx *ctx, u32 svc)
756 {
757         char *name;
758 
759         name = gss_service_to_auth_domain_name(ctx->mech_type, svc);
760         if (!name)
761                 return NULL;
762         return auth_domain_find(name);
763 }
764 
765 static struct auth_ops svcauthops_gss;
766 
767 u32 svcauth_gss_flavor(struct auth_domain *dom)
768 {
769         struct gss_domain *gd = container_of(dom, struct gss_domain, h);
770 
771         return gd->pseudoflavor;
772 }
773 
774 EXPORT_SYMBOL_GPL(svcauth_gss_flavor);
775 
776 int
777 svcauth_gss_register_pseudoflavor(u32 pseudoflavor, char * name)
778 {
779         struct gss_domain       *new;
780         struct auth_domain      *test;
781         int                     stat = -ENOMEM;
782 
783         new = kmalloc(sizeof(*new), GFP_KERNEL);
784         if (!new)
785                 goto out;
786         kref_init(&new->h.ref);
787         new->h.name = kstrdup(name, GFP_KERNEL);
788         if (!new->h.name)
789                 goto out_free_dom;
790         new->h.flavour = &svcauthops_gss;
791         new->pseudoflavor = pseudoflavor;
792 
793         stat = 0;
794         test = auth_domain_lookup(name, &new->h);
795         if (test != &new->h) { /* Duplicate registration */
796                 auth_domain_put(test);
797                 kfree(new->h.name);
798                 goto out_free_dom;
799         }
800         return 0;
801 
802 out_free_dom:
803         kfree(new);
804 out:
805         return stat;
806 }
807 
808 EXPORT_SYMBOL_GPL(svcauth_gss_register_pseudoflavor);
809 
810 static inline int
811 read_u32_from_xdr_buf(struct xdr_buf *buf, int base, u32 *obj)
812 {
813         __be32  raw;
814         int     status;
815 
816         status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
817         if (status)
818                 return status;
819         *obj = ntohl(raw);
820         return 0;
821 }
822 
823 /* It would be nice if this bit of code could be shared with the client.
824  * Obstacles:
825  *      The client shouldn't malloc(), would have to pass in own memory.
826  *      The server uses base of head iovec as read pointer, while the
827  *      client uses separate pointer. */
828 static int
829 unwrap_integ_data(struct svc_rqst *rqstp, struct xdr_buf *buf, u32 seq, struct gss_ctx *ctx)
830 {
831         int stat = -EINVAL;
832         u32 integ_len, maj_stat;
833         struct xdr_netobj mic;
834         struct xdr_buf integ_buf;
835 
836         /* Did we already verify the signature on the original pass through? */
837         if (rqstp->rq_deferred)
838                 return 0;
839 
840         integ_len = svc_getnl(&buf->head[0]);
841         if (integ_len & 3)
842                 return stat;
843         if (integ_len > buf->len)
844                 return stat;
845         if (xdr_buf_subsegment(buf, &integ_buf, 0, integ_len))
846                 BUG();
847         /* copy out mic... */
848         if (read_u32_from_xdr_buf(buf, integ_len, &mic.len))
849                 BUG();
850         if (mic.len > RPC_MAX_AUTH_SIZE)
851                 return stat;
852         mic.data = kmalloc(mic.len, GFP_KERNEL);
853         if (!mic.data)
854                 return stat;
855         if (read_bytes_from_xdr_buf(buf, integ_len + 4, mic.data, mic.len))
856                 goto out;
857         maj_stat = gss_verify_mic(ctx, &integ_buf, &mic);
858         if (maj_stat != GSS_S_COMPLETE)
859                 goto out;
860         if (svc_getnl(&buf->head[0]) != seq)
861                 goto out;
862         /* trim off the mic and padding at the end before returning */
863         xdr_buf_trim(buf, round_up_to_quad(mic.len) + 4);
864         stat = 0;
865 out:
866         kfree(mic.data);
867         return stat;
868 }
869 
870 static inline int
871 total_buf_len(struct xdr_buf *buf)
872 {
873         return buf->head[0].iov_len + buf->page_len + buf->tail[0].iov_len;
874 }
875 
876 static void
877 fix_priv_head(struct xdr_buf *buf, int pad)
878 {
879         if (buf->page_len == 0) {
880                 /* We need to adjust head and buf->len in tandem in this
881                  * case to make svc_defer() work--it finds the original
882                  * buffer start using buf->len - buf->head[0].iov_len. */
883                 buf->head[0].iov_len -= pad;
884         }
885 }
886 
887 static int
888 unwrap_priv_data(struct svc_rqst *rqstp, struct xdr_buf *buf, u32 seq, struct gss_ctx *ctx)
889 {
890         u32 priv_len, maj_stat;
891         int pad, saved_len, remaining_len, offset;
892 
893         rqstp->rq_splice_ok = 0;
894 
895         priv_len = svc_getnl(&buf->head[0]);
896         if (rqstp->rq_deferred) {
897                 /* Already decrypted last time through! The sequence number
898                  * check at out_seq is unnecessary but harmless: */
899                 goto out_seq;
900         }
901         /* buf->len is the number of bytes from the original start of the
902          * request to the end, where head[0].iov_len is just the bytes
903          * not yet read from the head, so these two values are different: */
904         remaining_len = total_buf_len(buf);
905         if (priv_len > remaining_len)
906                 return -EINVAL;
907         pad = remaining_len - priv_len;
908         buf->len -= pad;
909         fix_priv_head(buf, pad);
910 
911         /* Maybe it would be better to give gss_unwrap a length parameter: */
912         saved_len = buf->len;
913         buf->len = priv_len;
914         maj_stat = gss_unwrap(ctx, 0, buf);
915         pad = priv_len - buf->len;
916         buf->len = saved_len;
917         buf->len -= pad;
918         /* The upper layers assume the buffer is aligned on 4-byte boundaries.
919          * In the krb5p case, at least, the data ends up offset, so we need to
920          * move it around. */
921         /* XXX: This is very inefficient.  It would be better to either do
922          * this while we encrypt, or maybe in the receive code, if we can peak
923          * ahead and work out the service and mechanism there. */
924         offset = buf->head[0].iov_len % 4;
925         if (offset) {
926                 buf->buflen = RPCSVC_MAXPAYLOAD;
927                 xdr_shift_buf(buf, offset);
928                 fix_priv_head(buf, pad);
929         }
930         if (maj_stat != GSS_S_COMPLETE)
931                 return -EINVAL;
932 out_seq:
933         if (svc_getnl(&buf->head[0]) != seq)
934                 return -EINVAL;
935         return 0;
936 }
937 
938 struct gss_svc_data {
939         /* decoded gss client cred: */
940         struct rpc_gss_wire_cred        clcred;
941         /* save a pointer to the beginning of the encoded verifier,
942          * for use in encryption/checksumming in svcauth_gss_release: */
943         __be32                          *verf_start;
944         struct rsc                      *rsci;
945 };
946 
947 static int
948 svcauth_gss_set_client(struct svc_rqst *rqstp)
949 {
950         struct gss_svc_data *svcdata = rqstp->rq_auth_data;
951         struct rsc *rsci = svcdata->rsci;
952         struct rpc_gss_wire_cred *gc = &svcdata->clcred;
953         int stat;
954 
955         /*
956          * A gss export can be specified either by:
957          *      export  *(sec=krb5,rw)
958          * or by
959          *      export gss/krb5(rw)
960          * The latter is deprecated; but for backwards compatibility reasons
961          * the nfsd code will still fall back on trying it if the former
962          * doesn't work; so we try to make both available to nfsd, below.
963          */
964         rqstp->rq_gssclient = find_gss_auth_domain(rsci->mechctx, gc->gc_svc);
965         if (rqstp->rq_gssclient == NULL)
966                 return SVC_DENIED;
967         stat = svcauth_unix_set_client(rqstp);
968         if (stat == SVC_DROP || stat == SVC_CLOSE)
969                 return stat;
970         return SVC_OK;
971 }
972 
973 static inline int
974 gss_write_init_verf(struct cache_detail *cd, struct svc_rqst *rqstp,
975                 struct xdr_netobj *out_handle, int *major_status)
976 {
977         struct rsc *rsci;
978         int        rc;
979 
980         if (*major_status != GSS_S_COMPLETE)
981                 return gss_write_null_verf(rqstp);
982         rsci = gss_svc_searchbyctx(cd, out_handle);
983         if (rsci == NULL) {
984                 *major_status = GSS_S_NO_CONTEXT;
985                 return gss_write_null_verf(rqstp);
986         }
987         rc = gss_write_verf(rqstp, rsci->mechctx, GSS_SEQ_WIN);
988         cache_put(&rsci->h, cd);
989         return rc;
990 }
991 
992 static inline int
993 gss_read_common_verf(struct rpc_gss_wire_cred *gc,
994                      struct kvec *argv, __be32 *authp,
995                      struct xdr_netobj *in_handle)
996 {
997         /* Read the verifier; should be NULL: */
998         *authp = rpc_autherr_badverf;
999         if (argv->iov_len < 2 * 4)
1000                 return SVC_DENIED;
1001         if (svc_getnl(argv) != RPC_AUTH_NULL)
1002                 return SVC_DENIED;
1003         if (svc_getnl(argv) != 0)
1004                 return SVC_DENIED;
1005         /* Martial context handle and token for upcall: */
1006         *authp = rpc_autherr_badcred;
1007         if (gc->gc_proc == RPC_GSS_PROC_INIT && gc->gc_ctx.len != 0)
1008                 return SVC_DENIED;
1009         if (dup_netobj(in_handle, &gc->gc_ctx))
1010                 return SVC_CLOSE;
1011         *authp = rpc_autherr_badverf;
1012 
1013         return 0;
1014 }
1015 
1016 static inline int
1017 gss_read_verf(struct rpc_gss_wire_cred *gc,
1018               struct kvec *argv, __be32 *authp,
1019               struct xdr_netobj *in_handle,
1020               struct xdr_netobj *in_token)
1021 {
1022         struct xdr_netobj tmpobj;
1023         int res;
1024 
1025         res = gss_read_common_verf(gc, argv, authp, in_handle);
1026         if (res)
1027                 return res;
1028 
1029         if (svc_safe_getnetobj(argv, &tmpobj)) {
1030                 kfree(in_handle->data);
1031                 return SVC_DENIED;
1032         }
1033         if (dup_netobj(in_token, &tmpobj)) {
1034                 kfree(in_handle->data);
1035                 return SVC_CLOSE;
1036         }
1037 
1038         return 0;
1039 }
1040 
1041 /* Ok this is really heavily depending on a set of semantics in
1042  * how rqstp is set up by svc_recv and pages laid down by the
1043  * server when reading a request. We are basically guaranteed that
1044  * the token lays all down linearly across a set of pages, starting
1045  * at iov_base in rq_arg.head[0] which happens to be the first of a
1046  * set of pages stored in rq_pages[].
1047  * rq_arg.head[0].iov_base will provide us the page_base to pass
1048  * to the upcall.
1049  */
1050 static inline int
1051 gss_read_proxy_verf(struct svc_rqst *rqstp,
1052                     struct rpc_gss_wire_cred *gc, __be32 *authp,
1053                     struct xdr_netobj *in_handle,
1054                     struct gssp_in_token *in_token)
1055 {
1056         struct kvec *argv = &rqstp->rq_arg.head[0];
1057         u32 inlen;
1058         int res;
1059 
1060         res = gss_read_common_verf(gc, argv, authp, in_handle);
1061         if (res)
1062                 return res;
1063 
1064         inlen = svc_getnl(argv);
1065         if (inlen > (argv->iov_len + rqstp->rq_arg.page_len))
1066                 return SVC_DENIED;
1067 
1068         in_token->pages = rqstp->rq_pages;
1069         in_token->page_base = (ulong)argv->iov_base & ~PAGE_MASK;
1070         in_token->page_len = inlen;
1071 
1072         return 0;
1073 }
1074 
1075 static inline int
1076 gss_write_resv(struct kvec *resv, size_t size_limit,
1077                struct xdr_netobj *out_handle, struct xdr_netobj *out_token,
1078                int major_status, int minor_status)
1079 {
1080         if (resv->iov_len + 4 > size_limit)
1081                 return -1;
1082         svc_putnl(resv, RPC_SUCCESS);
1083         if (svc_safe_putnetobj(resv, out_handle))
1084                 return -1;
1085         if (resv->iov_len + 3 * 4 > size_limit)
1086                 return -1;
1087         svc_putnl(resv, major_status);
1088         svc_putnl(resv, minor_status);
1089         svc_putnl(resv, GSS_SEQ_WIN);
1090         if (svc_safe_putnetobj(resv, out_token))
1091                 return -1;
1092         return 0;
1093 }
1094 
1095 /*
1096  * Having read the cred already and found we're in the context
1097  * initiation case, read the verifier and initiate (or check the results
1098  * of) upcalls to userspace for help with context initiation.  If
1099  * the upcall results are available, write the verifier and result.
1100  * Otherwise, drop the request pending an answer to the upcall.
1101  */
1102 static int svcauth_gss_legacy_init(struct svc_rqst *rqstp,
1103                         struct rpc_gss_wire_cred *gc, __be32 *authp)
1104 {
1105         struct kvec *argv = &rqstp->rq_arg.head[0];
1106         struct kvec *resv = &rqstp->rq_res.head[0];
1107         struct rsi *rsip, rsikey;
1108         int ret;
1109         struct sunrpc_net *sn = net_generic(rqstp->rq_xprt->xpt_net, sunrpc_net_id);
1110 
1111         memset(&rsikey, 0, sizeof(rsikey));
1112         ret = gss_read_verf(gc, argv, authp,
1113                             &rsikey.in_handle, &rsikey.in_token);
1114         if (ret)
1115                 return ret;
1116 
1117         /* Perform upcall, or find upcall result: */
1118         rsip = rsi_lookup(sn->rsi_cache, &rsikey);
1119         rsi_free(&rsikey);
1120         if (!rsip)
1121                 return SVC_CLOSE;
1122         if (cache_check(sn->rsi_cache, &rsip->h, &rqstp->rq_chandle) < 0)
1123                 /* No upcall result: */
1124                 return SVC_CLOSE;
1125 
1126         ret = SVC_CLOSE;
1127         /* Got an answer to the upcall; use it: */
1128         if (gss_write_init_verf(sn->rsc_cache, rqstp,
1129                                 &rsip->out_handle, &rsip->major_status))
1130                 goto out;
1131         if (gss_write_resv(resv, PAGE_SIZE,
1132                            &rsip->out_handle, &rsip->out_token,
1133                            rsip->major_status, rsip->minor_status))
1134                 goto out;
1135 
1136         ret = SVC_COMPLETE;
1137 out:
1138         cache_put(&rsip->h, sn->rsi_cache);
1139         return ret;
1140 }
1141 
1142 static int gss_proxy_save_rsc(struct cache_detail *cd,
1143                                 struct gssp_upcall_data *ud,
1144                                 uint64_t *handle)
1145 {
1146         struct rsc rsci, *rscp = NULL;
1147         static atomic64_t ctxhctr;
1148         long long ctxh;
1149         struct gss_api_mech *gm = NULL;
1150         time_t expiry;
1151         int status = -EINVAL;
1152 
1153         memset(&rsci, 0, sizeof(rsci));
1154         /* context handle */
1155         status = -ENOMEM;
1156         /* the handle needs to be just a unique id,
1157          * use a static counter */
1158         ctxh = atomic64_inc_return(&ctxhctr);
1159 
1160         /* make a copy for the caller */
1161         *handle = ctxh;
1162 
1163         /* make a copy for the rsc cache */
1164         if (dup_to_netobj(&rsci.handle, (char *)handle, sizeof(uint64_t)))
1165                 goto out;
1166         rscp = rsc_lookup(cd, &rsci);
1167         if (!rscp)
1168                 goto out;
1169 
1170         /* creds */
1171         if (!ud->found_creds) {
1172                 /* userspace seem buggy, we should always get at least a
1173                  * mapping to nobody */
1174                 dprintk("RPC:       No creds found, marking Negative!\n");
1175                 set_bit(CACHE_NEGATIVE, &rsci.h.flags);
1176         } else {
1177 
1178                 /* steal creds */
1179                 rsci.cred = ud->creds;
1180                 memset(&ud->creds, 0, sizeof(struct svc_cred));
1181 
1182                 status = -EOPNOTSUPP;
1183                 /* get mech handle from OID */
1184                 gm = gss_mech_get_by_OID(&ud->mech_oid);
1185                 if (!gm)
1186                         goto out;
1187 
1188                 status = -EINVAL;
1189                 /* mech-specific data: */
1190                 status = gss_import_sec_context(ud->out_handle.data,
1191                                                 ud->out_handle.len,
1192                                                 gm, &rsci.mechctx,
1193                                                 &expiry, GFP_KERNEL);
1194                 if (status)
1195                         goto out;
1196         }
1197 
1198         rsci.h.expiry_time = expiry;
1199         rscp = rsc_update(cd, &rsci, rscp);
1200         status = 0;
1201 out:
1202         gss_mech_put(gm);
1203         rsc_free(&rsci);
1204         if (rscp)
1205                 cache_put(&rscp->h, cd);
1206         else
1207                 status = -ENOMEM;
1208         return status;
1209 }
1210 
1211 static int svcauth_gss_proxy_init(struct svc_rqst *rqstp,
1212                         struct rpc_gss_wire_cred *gc, __be32 *authp)
1213 {
1214         struct kvec *resv = &rqstp->rq_res.head[0];
1215         struct xdr_netobj cli_handle;
1216         struct gssp_upcall_data ud;
1217         uint64_t handle;
1218         int status;
1219         int ret;
1220         struct net *net = rqstp->rq_xprt->xpt_net;
1221         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1222 
1223         memset(&ud, 0, sizeof(ud));
1224         ret = gss_read_proxy_verf(rqstp, gc, authp,
1225                                   &ud.in_handle, &ud.in_token);
1226         if (ret)
1227                 return ret;
1228 
1229         ret = SVC_CLOSE;
1230 
1231         /* Perform synchronous upcall to gss-proxy */
1232         status = gssp_accept_sec_context_upcall(net, &ud);
1233         if (status)
1234                 goto out;
1235 
1236         dprintk("RPC:       svcauth_gss: gss major status = %d\n",
1237                         ud.major_status);
1238 
1239         switch (ud.major_status) {
1240         case GSS_S_CONTINUE_NEEDED:
1241                 cli_handle = ud.out_handle;
1242                 break;
1243         case GSS_S_COMPLETE:
1244                 status = gss_proxy_save_rsc(sn->rsc_cache, &ud, &handle);
1245                 if (status)
1246                         goto out;
1247                 cli_handle.data = (u8 *)&handle;
1248                 cli_handle.len = sizeof(handle);
1249                 break;
1250         default:
1251                 ret = SVC_CLOSE;
1252                 goto out;
1253         }
1254 
1255         /* Got an answer to the upcall; use it: */
1256         if (gss_write_init_verf(sn->rsc_cache, rqstp,
1257                                 &cli_handle, &ud.major_status))
1258                 goto out;
1259         if (gss_write_resv(resv, PAGE_SIZE,
1260                            &cli_handle, &ud.out_token,
1261                            ud.major_status, ud.minor_status))
1262                 goto out;
1263 
1264         ret = SVC_COMPLETE;
1265 out:
1266         gssp_free_upcall_data(&ud);
1267         return ret;
1268 }
1269 
1270 DEFINE_SPINLOCK(use_gssp_lock);
1271 
1272 static bool use_gss_proxy(struct net *net)
1273 {
1274         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1275 
1276         if (sn->use_gss_proxy != -1)
1277                 return sn->use_gss_proxy;
1278         spin_lock(&use_gssp_lock);
1279         /*
1280          * If you wanted gss-proxy, you should have said so before
1281          * starting to accept requests:
1282          */
1283         sn->use_gss_proxy = 0;
1284         spin_unlock(&use_gssp_lock);
1285         return 0;
1286 }
1287 
1288 #ifdef CONFIG_PROC_FS
1289 
1290 static int set_gss_proxy(struct net *net, int type)
1291 {
1292         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1293         int ret = 0;
1294 
1295         WARN_ON_ONCE(type != 0 && type != 1);
1296         spin_lock(&use_gssp_lock);
1297         if (sn->use_gss_proxy == -1 || sn->use_gss_proxy == type)
1298                 sn->use_gss_proxy = type;
1299         else
1300                 ret = -EBUSY;
1301         spin_unlock(&use_gssp_lock);
1302         wake_up(&sn->gssp_wq);
1303         return ret;
1304 }
1305 
1306 static inline bool gssp_ready(struct sunrpc_net *sn)
1307 {
1308         switch (sn->use_gss_proxy) {
1309                 case -1:
1310                         return false;
1311                 case 0:
1312                         return true;
1313                 case 1:
1314                         return sn->gssp_clnt;
1315         }
1316         WARN_ON_ONCE(1);
1317         return false;
1318 }
1319 
1320 static int wait_for_gss_proxy(struct net *net, struct file *file)
1321 {
1322         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1323 
1324         if (file->f_flags & O_NONBLOCK && !gssp_ready(sn))
1325                 return -EAGAIN;
1326         return wait_event_interruptible(sn->gssp_wq, gssp_ready(sn));
1327 }
1328 
1329 
1330 static ssize_t write_gssp(struct file *file, const char __user *buf,
1331                          size_t count, loff_t *ppos)
1332 {
1333         struct net *net = PDE_DATA(file->f_path.dentry->d_inode);
1334         char tbuf[20];
1335         unsigned long i;
1336         int res;
1337 
1338         if (*ppos || count > sizeof(tbuf)-1)
1339                 return -EINVAL;
1340         if (copy_from_user(tbuf, buf, count))
1341                 return -EFAULT;
1342 
1343         tbuf[count] = 0;
1344         res = kstrtoul(tbuf, 0, &i);
1345         if (res)
1346                 return res;
1347         if (i != 1)
1348                 return -EINVAL;
1349         res = set_gss_proxy(net, 1);
1350         if (res)
1351                 return res;
1352         res = set_gssp_clnt(net);
1353         if (res)
1354                 return res;
1355         return count;
1356 }
1357 
1358 static ssize_t read_gssp(struct file *file, char __user *buf,
1359                          size_t count, loff_t *ppos)
1360 {
1361         struct net *net = PDE_DATA(file->f_path.dentry->d_inode);
1362         unsigned long p = *ppos;
1363         char tbuf[10];
1364         size_t len;
1365         int ret;
1366 
1367         ret = wait_for_gss_proxy(net, file);
1368         if (ret)
1369                 return ret;
1370 
1371         snprintf(tbuf, sizeof(tbuf), "%d\n", use_gss_proxy(net));
1372         len = strlen(tbuf);
1373         if (p >= len)
1374                 return 0;
1375         len -= p;
1376         if (len > count)
1377                 len = count;
1378         if (copy_to_user(buf, (void *)(tbuf+p), len))
1379                 return -EFAULT;
1380         *ppos += len;
1381         return len;
1382 }
1383 
1384 static const struct file_operations use_gss_proxy_ops = {
1385         .open = nonseekable_open,
1386         .write = write_gssp,
1387         .read = read_gssp,
1388 };
1389 
1390 static int create_use_gss_proxy_proc_entry(struct net *net)
1391 {
1392         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1393         struct proc_dir_entry **p = &sn->use_gssp_proc;
1394 
1395         sn->use_gss_proxy = -1;
1396         *p = proc_create_data("use-gss-proxy", S_IFREG|S_IRUSR|S_IWUSR,
1397                               sn->proc_net_rpc,
1398                               &use_gss_proxy_ops, net);
1399         if (!*p)
1400                 return -ENOMEM;
1401         init_gssp_clnt(sn);
1402         return 0;
1403 }
1404 
1405 static void destroy_use_gss_proxy_proc_entry(struct net *net)
1406 {
1407         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1408 
1409         if (sn->use_gssp_proc) {
1410                 remove_proc_entry("use-gss-proxy", sn->proc_net_rpc); 
1411                 clear_gssp_clnt(sn);
1412         }
1413 }
1414 #else /* CONFIG_PROC_FS */
1415 
1416 static int create_use_gss_proxy_proc_entry(struct net *net)
1417 {
1418         return 0;
1419 }
1420 
1421 static void destroy_use_gss_proxy_proc_entry(struct net *net) {}
1422 
1423 #endif /* CONFIG_PROC_FS */
1424 
1425 /*
1426  * Accept an rpcsec packet.
1427  * If context establishment, punt to user space
1428  * If data exchange, verify/decrypt
1429  * If context destruction, handle here
1430  * In the context establishment and destruction case we encode
1431  * response here and return SVC_COMPLETE.
1432  */
1433 static int
1434 svcauth_gss_accept(struct svc_rqst *rqstp, __be32 *authp)
1435 {
1436         struct kvec     *argv = &rqstp->rq_arg.head[0];
1437         struct kvec     *resv = &rqstp->rq_res.head[0];
1438         u32             crlen;
1439         struct gss_svc_data *svcdata = rqstp->rq_auth_data;
1440         struct rpc_gss_wire_cred *gc;
1441         struct rsc      *rsci = NULL;
1442         __be32          *rpcstart;
1443         __be32          *reject_stat = resv->iov_base + resv->iov_len;
1444         int             ret;
1445         struct sunrpc_net *sn = net_generic(rqstp->rq_xprt->xpt_net, sunrpc_net_id);
1446 
1447         dprintk("RPC:       svcauth_gss: argv->iov_len = %zd\n",
1448                         argv->iov_len);
1449 
1450         *authp = rpc_autherr_badcred;
1451         if (!svcdata)
1452                 svcdata = kmalloc(sizeof(*svcdata), GFP_KERNEL);
1453         if (!svcdata)
1454                 goto auth_err;
1455         rqstp->rq_auth_data = svcdata;
1456         svcdata->verf_start = NULL;
1457         svcdata->rsci = NULL;
1458         gc = &svcdata->clcred;
1459 
1460         /* start of rpc packet is 7 u32's back from here:
1461          * xid direction rpcversion prog vers proc flavour
1462          */
1463         rpcstart = argv->iov_base;
1464         rpcstart -= 7;
1465 
1466         /* credential is:
1467          *   version(==1), proc(0,1,2,3), seq, service (1,2,3), handle
1468          * at least 5 u32s, and is preceded by length, so that makes 6.
1469          */
1470 
1471         if (argv->iov_len < 5 * 4)
1472                 goto auth_err;
1473         crlen = svc_getnl(argv);
1474         if (svc_getnl(argv) != RPC_GSS_VERSION)
1475                 goto auth_err;
1476         gc->gc_proc = svc_getnl(argv);
1477         gc->gc_seq = svc_getnl(argv);
1478         gc->gc_svc = svc_getnl(argv);
1479         if (svc_safe_getnetobj(argv, &gc->gc_ctx))
1480                 goto auth_err;
1481         if (crlen != round_up_to_quad(gc->gc_ctx.len) + 5 * 4)
1482                 goto auth_err;
1483 
1484         if ((gc->gc_proc != RPC_GSS_PROC_DATA) && (rqstp->rq_proc != 0))
1485                 goto auth_err;
1486 
1487         *authp = rpc_autherr_badverf;
1488         switch (gc->gc_proc) {
1489         case RPC_GSS_PROC_INIT:
1490         case RPC_GSS_PROC_CONTINUE_INIT:
1491                 if (use_gss_proxy(SVC_NET(rqstp)))
1492                         return svcauth_gss_proxy_init(rqstp, gc, authp);
1493                 else
1494                         return svcauth_gss_legacy_init(rqstp, gc, authp);
1495         case RPC_GSS_PROC_DATA:
1496         case RPC_GSS_PROC_DESTROY:
1497                 /* Look up the context, and check the verifier: */
1498                 *authp = rpcsec_gsserr_credproblem;
1499                 rsci = gss_svc_searchbyctx(sn->rsc_cache, &gc->gc_ctx);
1500                 if (!rsci)
1501                         goto auth_err;
1502                 switch (gss_verify_header(rqstp, rsci, rpcstart, gc, authp)) {
1503                 case SVC_OK:
1504                         break;
1505                 case SVC_DENIED:
1506                         goto auth_err;
1507                 case SVC_DROP:
1508                         goto drop;
1509                 }
1510                 break;
1511         default:
1512                 *authp = rpc_autherr_rejectedcred;
1513                 goto auth_err;
1514         }
1515 
1516         /* now act upon the command: */
1517         switch (gc->gc_proc) {
1518         case RPC_GSS_PROC_DESTROY:
1519                 if (gss_write_verf(rqstp, rsci->mechctx, gc->gc_seq))
1520                         goto auth_err;
1521                 rsci->h.expiry_time = seconds_since_boot();
1522                 set_bit(CACHE_NEGATIVE, &rsci->h.flags);
1523                 if (resv->iov_len + 4 > PAGE_SIZE)
1524                         goto drop;
1525                 svc_putnl(resv, RPC_SUCCESS);
1526                 goto complete;
1527         case RPC_GSS_PROC_DATA:
1528                 *authp = rpcsec_gsserr_ctxproblem;
1529                 svcdata->verf_start = resv->iov_base + resv->iov_len;
1530                 if (gss_write_verf(rqstp, rsci->mechctx, gc->gc_seq))
1531                         goto auth_err;
1532                 rqstp->rq_cred = rsci->cred;
1533                 get_group_info(rsci->cred.cr_group_info);
1534                 *authp = rpc_autherr_badcred;
1535                 switch (gc->gc_svc) {
1536                 case RPC_GSS_SVC_NONE:
1537                         break;
1538                 case RPC_GSS_SVC_INTEGRITY:
1539                         /* placeholders for length and seq. number: */
1540                         svc_putnl(resv, 0);
1541                         svc_putnl(resv, 0);
1542                         if (unwrap_integ_data(rqstp, &rqstp->rq_arg,
1543                                         gc->gc_seq, rsci->mechctx))
1544                                 goto garbage_args;
1545                         break;
1546                 case RPC_GSS_SVC_PRIVACY:
1547                         /* placeholders for length and seq. number: */
1548                         svc_putnl(resv, 0);
1549                         svc_putnl(resv, 0);
1550                         if (unwrap_priv_data(rqstp, &rqstp->rq_arg,
1551                                         gc->gc_seq, rsci->mechctx))
1552                                 goto garbage_args;
1553                         break;
1554                 default:
1555                         goto auth_err;
1556                 }
1557                 svcdata->rsci = rsci;
1558                 cache_get(&rsci->h);
1559                 rqstp->rq_cred.cr_flavor = gss_svc_to_pseudoflavor(
1560                                         rsci->mechctx->mech_type,
1561                                         GSS_C_QOP_DEFAULT,
1562                                         gc->gc_svc);
1563                 ret = SVC_OK;
1564                 goto out;
1565         }
1566 garbage_args:
1567         ret = SVC_GARBAGE;
1568         goto out;
1569 auth_err:
1570         /* Restore write pointer to its original value: */
1571         xdr_ressize_check(rqstp, reject_stat);
1572         ret = SVC_DENIED;
1573         goto out;
1574 complete:
1575         ret = SVC_COMPLETE;
1576         goto out;
1577 drop:
1578         ret = SVC_DROP;
1579 out:
1580         if (rsci)
1581                 cache_put(&rsci->h, sn->rsc_cache);
1582         return ret;
1583 }
1584 
1585 static __be32 *
1586 svcauth_gss_prepare_to_wrap(struct xdr_buf *resbuf, struct gss_svc_data *gsd)
1587 {
1588         __be32 *p;
1589         u32 verf_len;
1590 
1591         p = gsd->verf_start;
1592         gsd->verf_start = NULL;
1593 
1594         /* If the reply stat is nonzero, don't wrap: */
1595         if (*(p-1) != rpc_success)
1596                 return NULL;
1597         /* Skip the verifier: */
1598         p += 1;
1599         verf_len = ntohl(*p++);
1600         p += XDR_QUADLEN(verf_len);
1601         /* move accept_stat to right place: */
1602         memcpy(p, p + 2, 4);
1603         /* Also don't wrap if the accept stat is nonzero: */
1604         if (*p != rpc_success) {
1605                 resbuf->head[0].iov_len -= 2 * 4;
1606                 return NULL;
1607         }
1608         p++;
1609         return p;
1610 }
1611 
1612 static inline int
1613 svcauth_gss_wrap_resp_integ(struct svc_rqst *rqstp)
1614 {
1615         struct gss_svc_data *gsd = (struct gss_svc_data *)rqstp->rq_auth_data;
1616         struct rpc_gss_wire_cred *gc = &gsd->clcred;
1617         struct xdr_buf *resbuf = &rqstp->rq_res;
1618         struct xdr_buf integ_buf;
1619         struct xdr_netobj mic;
1620         struct kvec *resv;
1621         __be32 *p;
1622         int integ_offset, integ_len;
1623         int stat = -EINVAL;
1624 
1625         p = svcauth_gss_prepare_to_wrap(resbuf, gsd);
1626         if (p == NULL)
1627                 goto out;
1628         integ_offset = (u8 *)(p + 1) - (u8 *)resbuf->head[0].iov_base;
1629         integ_len = resbuf->len - integ_offset;
1630         BUG_ON(integ_len % 4);
1631         *p++ = htonl(integ_len);
1632         *p++ = htonl(gc->gc_seq);
1633         if (xdr_buf_subsegment(resbuf, &integ_buf, integ_offset,
1634                                 integ_len))
1635                 BUG();
1636         if (resbuf->tail[0].iov_base == NULL) {
1637                 if (resbuf->head[0].iov_len + RPC_MAX_AUTH_SIZE > PAGE_SIZE)
1638                         goto out_err;
1639                 resbuf->tail[0].iov_base = resbuf->head[0].iov_base
1640                                                 + resbuf->head[0].iov_len;
1641                 resbuf->tail[0].iov_len = 0;
1642                 resv = &resbuf->tail[0];
1643         } else {
1644                 resv = &resbuf->tail[0];
1645         }
1646         mic.data = (u8 *)resv->iov_base + resv->iov_len + 4;
1647         if (gss_get_mic(gsd->rsci->mechctx, &integ_buf, &mic))
1648                 goto out_err;
1649         svc_putnl(resv, mic.len);
1650         memset(mic.data + mic.len, 0,
1651                         round_up_to_quad(mic.len) - mic.len);
1652         resv->iov_len += XDR_QUADLEN(mic.len) << 2;
1653         /* not strictly required: */
1654         resbuf->len += XDR_QUADLEN(mic.len) << 2;
1655         BUG_ON(resv->iov_len > PAGE_SIZE);
1656 out:
1657         stat = 0;
1658 out_err:
1659         return stat;
1660 }
1661 
1662 static inline int
1663 svcauth_gss_wrap_resp_priv(struct svc_rqst *rqstp)
1664 {
1665         struct gss_svc_data *gsd = (struct gss_svc_data *)rqstp->rq_auth_data;
1666         struct rpc_gss_wire_cred *gc = &gsd->clcred;
1667         struct xdr_buf *resbuf = &rqstp->rq_res;
1668         struct page **inpages = NULL;
1669         __be32 *p, *len;
1670         int offset;
1671         int pad;
1672 
1673         p = svcauth_gss_prepare_to_wrap(resbuf, gsd);
1674         if (p == NULL)
1675                 return 0;
1676         len = p++;
1677         offset = (u8 *)p - (u8 *)resbuf->head[0].iov_base;
1678         *p++ = htonl(gc->gc_seq);
1679         inpages = resbuf->pages;
1680         /* XXX: Would be better to write some xdr helper functions for
1681          * nfs{2,3,4}xdr.c that place the data right, instead of copying: */
1682 
1683         /*
1684          * If there is currently tail data, make sure there is
1685          * room for the head, tail, and 2 * RPC_MAX_AUTH_SIZE in
1686          * the page, and move the current tail data such that
1687          * there is RPC_MAX_AUTH_SIZE slack space available in
1688          * both the head and tail.
1689          */
1690         if (resbuf->tail[0].iov_base) {
1691                 BUG_ON(resbuf->tail[0].iov_base >= resbuf->head[0].iov_base
1692                                                         + PAGE_SIZE);
1693                 BUG_ON(resbuf->tail[0].iov_base < resbuf->head[0].iov_base);
1694                 if (resbuf->tail[0].iov_len + resbuf->head[0].iov_len
1695                                 + 2 * RPC_MAX_AUTH_SIZE > PAGE_SIZE)
1696                         return -ENOMEM;
1697                 memmove(resbuf->tail[0].iov_base + RPC_MAX_AUTH_SIZE,
1698                         resbuf->tail[0].iov_base,
1699                         resbuf->tail[0].iov_len);
1700                 resbuf->tail[0].iov_base += RPC_MAX_AUTH_SIZE;
1701         }
1702         /*
1703          * If there is no current tail data, make sure there is
1704          * room for the head data, and 2 * RPC_MAX_AUTH_SIZE in the
1705          * allotted page, and set up tail information such that there
1706          * is RPC_MAX_AUTH_SIZE slack space available in both the
1707          * head and tail.
1708          */
1709         if (resbuf->tail[0].iov_base == NULL) {
1710                 if (resbuf->head[0].iov_len + 2*RPC_MAX_AUTH_SIZE > PAGE_SIZE)
1711                         return -ENOMEM;
1712                 resbuf->tail[0].iov_base = resbuf->head[0].iov_base
1713                         + resbuf->head[0].iov_len + RPC_MAX_AUTH_SIZE;
1714                 resbuf->tail[0].iov_len = 0;
1715         }
1716         if (gss_wrap(gsd->rsci->mechctx, offset, resbuf, inpages))
1717                 return -ENOMEM;
1718         *len = htonl(resbuf->len - offset);
1719         pad = 3 - ((resbuf->len - offset - 1)&3);
1720         p = (__be32 *)(resbuf->tail[0].iov_base + resbuf->tail[0].iov_len);
1721         memset(p, 0, pad);
1722         resbuf->tail[0].iov_len += pad;
1723         resbuf->len += pad;
1724         return 0;
1725 }
1726 
1727 static int
1728 svcauth_gss_release(struct svc_rqst *rqstp)
1729 {
1730         struct gss_svc_data *gsd = (struct gss_svc_data *)rqstp->rq_auth_data;
1731         struct rpc_gss_wire_cred *gc = &gsd->clcred;
1732         struct xdr_buf *resbuf = &rqstp->rq_res;
1733         int stat = -EINVAL;
1734         struct sunrpc_net *sn = net_generic(rqstp->rq_xprt->xpt_net, sunrpc_net_id);
1735 
1736         if (gc->gc_proc != RPC_GSS_PROC_DATA)
1737                 goto out;
1738         /* Release can be called twice, but we only wrap once. */
1739         if (gsd->verf_start == NULL)
1740                 goto out;
1741         /* normally not set till svc_send, but we need it here: */
1742         /* XXX: what for?  Do we mess it up the moment we call svc_putu32
1743          * or whatever? */
1744         resbuf->len = total_buf_len(resbuf);
1745         switch (gc->gc_svc) {
1746         case RPC_GSS_SVC_NONE:
1747                 break;
1748         case RPC_GSS_SVC_INTEGRITY:
1749                 stat = svcauth_gss_wrap_resp_integ(rqstp);
1750                 if (stat)
1751                         goto out_err;
1752                 break;
1753         case RPC_GSS_SVC_PRIVACY:
1754                 stat = svcauth_gss_wrap_resp_priv(rqstp);
1755                 if (stat)
1756                         goto out_err;
1757                 break;
1758         /*
1759          * For any other gc_svc value, svcauth_gss_accept() already set
1760          * the auth_error appropriately; just fall through:
1761          */
1762         }
1763 
1764 out:
1765         stat = 0;
1766 out_err:
1767         if (rqstp->rq_client)
1768                 auth_domain_put(rqstp->rq_client);
1769         rqstp->rq_client = NULL;
1770         if (rqstp->rq_gssclient)
1771                 auth_domain_put(rqstp->rq_gssclient);
1772         rqstp->rq_gssclient = NULL;
1773         if (rqstp->rq_cred.cr_group_info)
1774                 put_group_info(rqstp->rq_cred.cr_group_info);
1775         rqstp->rq_cred.cr_group_info = NULL;
1776         if (gsd->rsci)
1777                 cache_put(&gsd->rsci->h, sn->rsc_cache);
1778         gsd->rsci = NULL;
1779 
1780         return stat;
1781 }
1782 
1783 static void
1784 svcauth_gss_domain_release(struct auth_domain *dom)
1785 {
1786         struct gss_domain *gd = container_of(dom, struct gss_domain, h);
1787 
1788         kfree(dom->name);
1789         kfree(gd);
1790 }
1791 
1792 static struct auth_ops svcauthops_gss = {
1793         .name           = "rpcsec_gss",
1794         .owner          = THIS_MODULE,
1795         .flavour        = RPC_AUTH_GSS,
1796         .accept         = svcauth_gss_accept,
1797         .release        = svcauth_gss_release,
1798         .domain_release = svcauth_gss_domain_release,
1799         .set_client     = svcauth_gss_set_client,
1800 };
1801 
1802 static int rsi_cache_create_net(struct net *net)
1803 {
1804         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1805         struct cache_detail *cd;
1806         int err;
1807 
1808         cd = cache_create_net(&rsi_cache_template, net);
1809         if (IS_ERR(cd))
1810                 return PTR_ERR(cd);
1811         err = cache_register_net(cd, net);
1812         if (err) {
1813                 cache_destroy_net(cd, net);
1814                 return err;
1815         }
1816         sn->rsi_cache = cd;
1817         return 0;
1818 }
1819 
1820 static void rsi_cache_destroy_net(struct net *net)
1821 {
1822         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1823         struct cache_detail *cd = sn->rsi_cache;
1824 
1825         sn->rsi_cache = NULL;
1826         cache_purge(cd);
1827         cache_unregister_net(cd, net);
1828         cache_destroy_net(cd, net);
1829 }
1830 
1831 static int rsc_cache_create_net(struct net *net)
1832 {
1833         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1834         struct cache_detail *cd;
1835         int err;
1836 
1837         cd = cache_create_net(&rsc_cache_template, net);
1838         if (IS_ERR(cd))
1839                 return PTR_ERR(cd);
1840         err = cache_register_net(cd, net);
1841         if (err) {
1842                 cache_destroy_net(cd, net);
1843                 return err;
1844         }
1845         sn->rsc_cache = cd;
1846         return 0;
1847 }
1848 
1849 static void rsc_cache_destroy_net(struct net *net)
1850 {
1851         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1852         struct cache_detail *cd = sn->rsc_cache;
1853 
1854         sn->rsc_cache = NULL;
1855         cache_purge(cd);
1856         cache_unregister_net(cd, net);
1857         cache_destroy_net(cd, net);
1858 }
1859 
1860 int
1861 gss_svc_init_net(struct net *net)
1862 {
1863         int rv;
1864 
1865         rv = rsc_cache_create_net(net);
1866         if (rv)
1867                 return rv;
1868         rv = rsi_cache_create_net(net);
1869         if (rv)
1870                 goto out1;
1871         rv = create_use_gss_proxy_proc_entry(net);
1872         if (rv)
1873                 goto out2;
1874         return 0;
1875 out2:
1876         destroy_use_gss_proxy_proc_entry(net);
1877 out1:
1878         rsc_cache_destroy_net(net);
1879         return rv;
1880 }
1881 
1882 void
1883 gss_svc_shutdown_net(struct net *net)
1884 {
1885         destroy_use_gss_proxy_proc_entry(net);
1886         rsi_cache_destroy_net(net);
1887         rsc_cache_destroy_net(net);
1888 }
1889 
1890 int
1891 gss_svc_init(void)
1892 {
1893         return svc_auth_register(RPC_AUTH_GSS, &svcauthops_gss);
1894 }
1895 
1896 void
1897 gss_svc_shutdown(void)
1898 {
1899         svc_auth_unregister(RPC_AUTH_GSS);
1900 }
1901 

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