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Linux/net/sunrpc/auth_gss/auth_gss.c

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  1 // SPDX-License-Identifier: BSD-3-Clause
  2 /*
  3  * linux/net/sunrpc/auth_gss/auth_gss.c
  4  *
  5  * RPCSEC_GSS client authentication.
  6  *
  7  *  Copyright (c) 2000 The Regents of the University of Michigan.
  8  *  All rights reserved.
  9  *
 10  *  Dug Song       <dugsong@monkey.org>
 11  *  Andy Adamson   <andros@umich.edu>
 12  */
 13 
 14 #include <linux/module.h>
 15 #include <linux/init.h>
 16 #include <linux/types.h>
 17 #include <linux/slab.h>
 18 #include <linux/sched.h>
 19 #include <linux/pagemap.h>
 20 #include <linux/sunrpc/clnt.h>
 21 #include <linux/sunrpc/auth.h>
 22 #include <linux/sunrpc/auth_gss.h>
 23 #include <linux/sunrpc/svcauth_gss.h>
 24 #include <linux/sunrpc/gss_err.h>
 25 #include <linux/workqueue.h>
 26 #include <linux/sunrpc/rpc_pipe_fs.h>
 27 #include <linux/sunrpc/gss_api.h>
 28 #include <linux/uaccess.h>
 29 #include <linux/hashtable.h>
 30 
 31 #include "../netns.h"
 32 
 33 #include <trace/events/rpcgss.h>
 34 
 35 static const struct rpc_authops authgss_ops;
 36 
 37 static const struct rpc_credops gss_credops;
 38 static const struct rpc_credops gss_nullops;
 39 
 40 #define GSS_RETRY_EXPIRED 5
 41 static unsigned int gss_expired_cred_retry_delay = GSS_RETRY_EXPIRED;
 42 
 43 #define GSS_KEY_EXPIRE_TIMEO 240
 44 static unsigned int gss_key_expire_timeo = GSS_KEY_EXPIRE_TIMEO;
 45 
 46 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 47 # define RPCDBG_FACILITY        RPCDBG_AUTH
 48 #endif
 49 
 50 #define GSS_CRED_SLACK          (RPC_MAX_AUTH_SIZE * 2)
 51 /* length of a krb5 verifier (48), plus data added before arguments when
 52  * using integrity (two 4-byte integers): */
 53 #define GSS_VERF_SLACK          100
 54 
 55 static DEFINE_HASHTABLE(gss_auth_hash_table, 4);
 56 static DEFINE_SPINLOCK(gss_auth_hash_lock);
 57 
 58 struct gss_pipe {
 59         struct rpc_pipe_dir_object pdo;
 60         struct rpc_pipe *pipe;
 61         struct rpc_clnt *clnt;
 62         const char *name;
 63         struct kref kref;
 64 };
 65 
 66 struct gss_auth {
 67         struct kref kref;
 68         struct hlist_node hash;
 69         struct rpc_auth rpc_auth;
 70         struct gss_api_mech *mech;
 71         enum rpc_gss_svc service;
 72         struct rpc_clnt *client;
 73         struct net *net;
 74         /*
 75          * There are two upcall pipes; dentry[1], named "gssd", is used
 76          * for the new text-based upcall; dentry[0] is named after the
 77          * mechanism (for example, "krb5") and exists for
 78          * backwards-compatibility with older gssd's.
 79          */
 80         struct gss_pipe *gss_pipe[2];
 81         const char *target_name;
 82 };
 83 
 84 /* pipe_version >= 0 if and only if someone has a pipe open. */
 85 static DEFINE_SPINLOCK(pipe_version_lock);
 86 static struct rpc_wait_queue pipe_version_rpc_waitqueue;
 87 static DECLARE_WAIT_QUEUE_HEAD(pipe_version_waitqueue);
 88 static void gss_put_auth(struct gss_auth *gss_auth);
 89 
 90 static void gss_free_ctx(struct gss_cl_ctx *);
 91 static const struct rpc_pipe_ops gss_upcall_ops_v0;
 92 static const struct rpc_pipe_ops gss_upcall_ops_v1;
 93 
 94 static inline struct gss_cl_ctx *
 95 gss_get_ctx(struct gss_cl_ctx *ctx)
 96 {
 97         refcount_inc(&ctx->count);
 98         return ctx;
 99 }
100 
101 static inline void
102 gss_put_ctx(struct gss_cl_ctx *ctx)
103 {
104         if (refcount_dec_and_test(&ctx->count))
105                 gss_free_ctx(ctx);
106 }
107 
108 /* gss_cred_set_ctx:
109  * called by gss_upcall_callback and gss_create_upcall in order
110  * to set the gss context. The actual exchange of an old context
111  * and a new one is protected by the pipe->lock.
112  */
113 static void
114 gss_cred_set_ctx(struct rpc_cred *cred, struct gss_cl_ctx *ctx)
115 {
116         struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
117 
118         if (!test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags))
119                 return;
120         gss_get_ctx(ctx);
121         rcu_assign_pointer(gss_cred->gc_ctx, ctx);
122         set_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
123         smp_mb__before_atomic();
124         clear_bit(RPCAUTH_CRED_NEW, &cred->cr_flags);
125 }
126 
127 static const void *
128 simple_get_bytes(const void *p, const void *end, void *res, size_t len)
129 {
130         const void *q = (const void *)((const char *)p + len);
131         if (unlikely(q > end || q < p))
132                 return ERR_PTR(-EFAULT);
133         memcpy(res, p, len);
134         return q;
135 }
136 
137 static inline const void *
138 simple_get_netobj(const void *p, const void *end, struct xdr_netobj *dest)
139 {
140         const void *q;
141         unsigned int len;
142 
143         p = simple_get_bytes(p, end, &len, sizeof(len));
144         if (IS_ERR(p))
145                 return p;
146         q = (const void *)((const char *)p + len);
147         if (unlikely(q > end || q < p))
148                 return ERR_PTR(-EFAULT);
149         dest->data = kmemdup(p, len, GFP_NOFS);
150         if (unlikely(dest->data == NULL))
151                 return ERR_PTR(-ENOMEM);
152         dest->len = len;
153         return q;
154 }
155 
156 static struct gss_cl_ctx *
157 gss_cred_get_ctx(struct rpc_cred *cred)
158 {
159         struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
160         struct gss_cl_ctx *ctx = NULL;
161 
162         rcu_read_lock();
163         ctx = rcu_dereference(gss_cred->gc_ctx);
164         if (ctx)
165                 gss_get_ctx(ctx);
166         rcu_read_unlock();
167         return ctx;
168 }
169 
170 static struct gss_cl_ctx *
171 gss_alloc_context(void)
172 {
173         struct gss_cl_ctx *ctx;
174 
175         ctx = kzalloc(sizeof(*ctx), GFP_NOFS);
176         if (ctx != NULL) {
177                 ctx->gc_proc = RPC_GSS_PROC_DATA;
178                 ctx->gc_seq = 1;        /* NetApp 6.4R1 doesn't accept seq. no. 0 */
179                 spin_lock_init(&ctx->gc_seq_lock);
180                 refcount_set(&ctx->count,1);
181         }
182         return ctx;
183 }
184 
185 #define GSSD_MIN_TIMEOUT (60 * 60)
186 static const void *
187 gss_fill_context(const void *p, const void *end, struct gss_cl_ctx *ctx, struct gss_api_mech *gm)
188 {
189         const void *q;
190         unsigned int seclen;
191         unsigned int timeout;
192         unsigned long now = jiffies;
193         u32 window_size;
194         int ret;
195 
196         /* First unsigned int gives the remaining lifetime in seconds of the
197          * credential - e.g. the remaining TGT lifetime for Kerberos or
198          * the -t value passed to GSSD.
199          */
200         p = simple_get_bytes(p, end, &timeout, sizeof(timeout));
201         if (IS_ERR(p))
202                 goto err;
203         if (timeout == 0)
204                 timeout = GSSD_MIN_TIMEOUT;
205         ctx->gc_expiry = now + ((unsigned long)timeout * HZ);
206         /* Sequence number window. Determines the maximum number of
207          * simultaneous requests
208          */
209         p = simple_get_bytes(p, end, &window_size, sizeof(window_size));
210         if (IS_ERR(p))
211                 goto err;
212         ctx->gc_win = window_size;
213         /* gssd signals an error by passing ctx->gc_win = 0: */
214         if (ctx->gc_win == 0) {
215                 /*
216                  * in which case, p points to an error code. Anything other
217                  * than -EKEYEXPIRED gets converted to -EACCES.
218                  */
219                 p = simple_get_bytes(p, end, &ret, sizeof(ret));
220                 if (!IS_ERR(p))
221                         p = (ret == -EKEYEXPIRED) ? ERR_PTR(-EKEYEXPIRED) :
222                                                     ERR_PTR(-EACCES);
223                 goto err;
224         }
225         /* copy the opaque wire context */
226         p = simple_get_netobj(p, end, &ctx->gc_wire_ctx);
227         if (IS_ERR(p))
228                 goto err;
229         /* import the opaque security context */
230         p  = simple_get_bytes(p, end, &seclen, sizeof(seclen));
231         if (IS_ERR(p))
232                 goto err;
233         q = (const void *)((const char *)p + seclen);
234         if (unlikely(q > end || q < p)) {
235                 p = ERR_PTR(-EFAULT);
236                 goto err;
237         }
238         ret = gss_import_sec_context(p, seclen, gm, &ctx->gc_gss_ctx, NULL, GFP_NOFS);
239         if (ret < 0) {
240                 trace_rpcgss_import_ctx(ret);
241                 p = ERR_PTR(ret);
242                 goto err;
243         }
244 
245         /* is there any trailing data? */
246         if (q == end) {
247                 p = q;
248                 goto done;
249         }
250 
251         /* pull in acceptor name (if there is one) */
252         p = simple_get_netobj(q, end, &ctx->gc_acceptor);
253         if (IS_ERR(p))
254                 goto err;
255 done:
256         trace_rpcgss_context(ctx->gc_expiry, now, timeout,
257                              ctx->gc_acceptor.len, ctx->gc_acceptor.data);
258 err:
259         return p;
260 }
261 
262 /* XXX: Need some documentation about why UPCALL_BUF_LEN is so small.
263  *      Is user space expecting no more than UPCALL_BUF_LEN bytes?
264  *      Note that there are now _two_ NI_MAXHOST sized data items
265  *      being passed in this string.
266  */
267 #define UPCALL_BUF_LEN  256
268 
269 struct gss_upcall_msg {
270         refcount_t count;
271         kuid_t  uid;
272         const char *service_name;
273         struct rpc_pipe_msg msg;
274         struct list_head list;
275         struct gss_auth *auth;
276         struct rpc_pipe *pipe;
277         struct rpc_wait_queue rpc_waitqueue;
278         wait_queue_head_t waitqueue;
279         struct gss_cl_ctx *ctx;
280         char databuf[UPCALL_BUF_LEN];
281 };
282 
283 static int get_pipe_version(struct net *net)
284 {
285         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
286         int ret;
287 
288         spin_lock(&pipe_version_lock);
289         if (sn->pipe_version >= 0) {
290                 atomic_inc(&sn->pipe_users);
291                 ret = sn->pipe_version;
292         } else
293                 ret = -EAGAIN;
294         spin_unlock(&pipe_version_lock);
295         return ret;
296 }
297 
298 static void put_pipe_version(struct net *net)
299 {
300         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
301 
302         if (atomic_dec_and_lock(&sn->pipe_users, &pipe_version_lock)) {
303                 sn->pipe_version = -1;
304                 spin_unlock(&pipe_version_lock);
305         }
306 }
307 
308 static void
309 gss_release_msg(struct gss_upcall_msg *gss_msg)
310 {
311         struct net *net = gss_msg->auth->net;
312         if (!refcount_dec_and_test(&gss_msg->count))
313                 return;
314         put_pipe_version(net);
315         BUG_ON(!list_empty(&gss_msg->list));
316         if (gss_msg->ctx != NULL)
317                 gss_put_ctx(gss_msg->ctx);
318         rpc_destroy_wait_queue(&gss_msg->rpc_waitqueue);
319         gss_put_auth(gss_msg->auth);
320         kfree_const(gss_msg->service_name);
321         kfree(gss_msg);
322 }
323 
324 static struct gss_upcall_msg *
325 __gss_find_upcall(struct rpc_pipe *pipe, kuid_t uid, const struct gss_auth *auth)
326 {
327         struct gss_upcall_msg *pos;
328         list_for_each_entry(pos, &pipe->in_downcall, list) {
329                 if (!uid_eq(pos->uid, uid))
330                         continue;
331                 if (auth && pos->auth->service != auth->service)
332                         continue;
333                 refcount_inc(&pos->count);
334                 return pos;
335         }
336         return NULL;
337 }
338 
339 /* Try to add an upcall to the pipefs queue.
340  * If an upcall owned by our uid already exists, then we return a reference
341  * to that upcall instead of adding the new upcall.
342  */
343 static inline struct gss_upcall_msg *
344 gss_add_msg(struct gss_upcall_msg *gss_msg)
345 {
346         struct rpc_pipe *pipe = gss_msg->pipe;
347         struct gss_upcall_msg *old;
348 
349         spin_lock(&pipe->lock);
350         old = __gss_find_upcall(pipe, gss_msg->uid, gss_msg->auth);
351         if (old == NULL) {
352                 refcount_inc(&gss_msg->count);
353                 list_add(&gss_msg->list, &pipe->in_downcall);
354         } else
355                 gss_msg = old;
356         spin_unlock(&pipe->lock);
357         return gss_msg;
358 }
359 
360 static void
361 __gss_unhash_msg(struct gss_upcall_msg *gss_msg)
362 {
363         list_del_init(&gss_msg->list);
364         rpc_wake_up_status(&gss_msg->rpc_waitqueue, gss_msg->msg.errno);
365         wake_up_all(&gss_msg->waitqueue);
366         refcount_dec(&gss_msg->count);
367 }
368 
369 static void
370 gss_unhash_msg(struct gss_upcall_msg *gss_msg)
371 {
372         struct rpc_pipe *pipe = gss_msg->pipe;
373 
374         if (list_empty(&gss_msg->list))
375                 return;
376         spin_lock(&pipe->lock);
377         if (!list_empty(&gss_msg->list))
378                 __gss_unhash_msg(gss_msg);
379         spin_unlock(&pipe->lock);
380 }
381 
382 static void
383 gss_handle_downcall_result(struct gss_cred *gss_cred, struct gss_upcall_msg *gss_msg)
384 {
385         switch (gss_msg->msg.errno) {
386         case 0:
387                 if (gss_msg->ctx == NULL)
388                         break;
389                 clear_bit(RPCAUTH_CRED_NEGATIVE, &gss_cred->gc_base.cr_flags);
390                 gss_cred_set_ctx(&gss_cred->gc_base, gss_msg->ctx);
391                 break;
392         case -EKEYEXPIRED:
393                 set_bit(RPCAUTH_CRED_NEGATIVE, &gss_cred->gc_base.cr_flags);
394         }
395         gss_cred->gc_upcall_timestamp = jiffies;
396         gss_cred->gc_upcall = NULL;
397         rpc_wake_up_status(&gss_msg->rpc_waitqueue, gss_msg->msg.errno);
398 }
399 
400 static void
401 gss_upcall_callback(struct rpc_task *task)
402 {
403         struct gss_cred *gss_cred = container_of(task->tk_rqstp->rq_cred,
404                         struct gss_cred, gc_base);
405         struct gss_upcall_msg *gss_msg = gss_cred->gc_upcall;
406         struct rpc_pipe *pipe = gss_msg->pipe;
407 
408         spin_lock(&pipe->lock);
409         gss_handle_downcall_result(gss_cred, gss_msg);
410         spin_unlock(&pipe->lock);
411         task->tk_status = gss_msg->msg.errno;
412         gss_release_msg(gss_msg);
413 }
414 
415 static void gss_encode_v0_msg(struct gss_upcall_msg *gss_msg,
416                               const struct cred *cred)
417 {
418         struct user_namespace *userns = cred->user_ns;
419 
420         uid_t uid = from_kuid_munged(userns, gss_msg->uid);
421         memcpy(gss_msg->databuf, &uid, sizeof(uid));
422         gss_msg->msg.data = gss_msg->databuf;
423         gss_msg->msg.len = sizeof(uid);
424 
425         BUILD_BUG_ON(sizeof(uid) > sizeof(gss_msg->databuf));
426 }
427 
428 static ssize_t
429 gss_v0_upcall(struct file *file, struct rpc_pipe_msg *msg,
430                 char __user *buf, size_t buflen)
431 {
432         struct gss_upcall_msg *gss_msg = container_of(msg,
433                                                       struct gss_upcall_msg,
434                                                       msg);
435         if (msg->copied == 0)
436                 gss_encode_v0_msg(gss_msg, file->f_cred);
437         return rpc_pipe_generic_upcall(file, msg, buf, buflen);
438 }
439 
440 static int gss_encode_v1_msg(struct gss_upcall_msg *gss_msg,
441                                 const char *service_name,
442                                 const char *target_name,
443                                 const struct cred *cred)
444 {
445         struct user_namespace *userns = cred->user_ns;
446         struct gss_api_mech *mech = gss_msg->auth->mech;
447         char *p = gss_msg->databuf;
448         size_t buflen = sizeof(gss_msg->databuf);
449         int len;
450 
451         len = scnprintf(p, buflen, "mech=%s uid=%d", mech->gm_name,
452                         from_kuid_munged(userns, gss_msg->uid));
453         buflen -= len;
454         p += len;
455         gss_msg->msg.len = len;
456 
457         /*
458          * target= is a full service principal that names the remote
459          * identity that we are authenticating to.
460          */
461         if (target_name) {
462                 len = scnprintf(p, buflen, " target=%s", target_name);
463                 buflen -= len;
464                 p += len;
465                 gss_msg->msg.len += len;
466         }
467 
468         /*
469          * gssd uses service= and srchost= to select a matching key from
470          * the system's keytab to use as the source principal.
471          *
472          * service= is the service name part of the source principal,
473          * or "*" (meaning choose any).
474          *
475          * srchost= is the hostname part of the source principal. When
476          * not provided, gssd uses the local hostname.
477          */
478         if (service_name) {
479                 char *c = strchr(service_name, '@');
480 
481                 if (!c)
482                         len = scnprintf(p, buflen, " service=%s",
483                                         service_name);
484                 else
485                         len = scnprintf(p, buflen,
486                                         " service=%.*s srchost=%s",
487                                         (int)(c - service_name),
488                                         service_name, c + 1);
489                 buflen -= len;
490                 p += len;
491                 gss_msg->msg.len += len;
492         }
493 
494         if (mech->gm_upcall_enctypes) {
495                 len = scnprintf(p, buflen, " enctypes=%s",
496                                 mech->gm_upcall_enctypes);
497                 buflen -= len;
498                 p += len;
499                 gss_msg->msg.len += len;
500         }
501         trace_rpcgss_upcall_msg(gss_msg->databuf);
502         len = scnprintf(p, buflen, "\n");
503         if (len == 0)
504                 goto out_overflow;
505         gss_msg->msg.len += len;
506         gss_msg->msg.data = gss_msg->databuf;
507         return 0;
508 out_overflow:
509         WARN_ON_ONCE(1);
510         return -ENOMEM;
511 }
512 
513 static ssize_t
514 gss_v1_upcall(struct file *file, struct rpc_pipe_msg *msg,
515                 char __user *buf, size_t buflen)
516 {
517         struct gss_upcall_msg *gss_msg = container_of(msg,
518                                                       struct gss_upcall_msg,
519                                                       msg);
520         int err;
521         if (msg->copied == 0) {
522                 err = gss_encode_v1_msg(gss_msg,
523                                         gss_msg->service_name,
524                                         gss_msg->auth->target_name,
525                                         file->f_cred);
526                 if (err)
527                         return err;
528         }
529         return rpc_pipe_generic_upcall(file, msg, buf, buflen);
530 }
531 
532 static struct gss_upcall_msg *
533 gss_alloc_msg(struct gss_auth *gss_auth,
534                 kuid_t uid, const char *service_name)
535 {
536         struct gss_upcall_msg *gss_msg;
537         int vers;
538         int err = -ENOMEM;
539 
540         gss_msg = kzalloc(sizeof(*gss_msg), GFP_NOFS);
541         if (gss_msg == NULL)
542                 goto err;
543         vers = get_pipe_version(gss_auth->net);
544         err = vers;
545         if (err < 0)
546                 goto err_free_msg;
547         gss_msg->pipe = gss_auth->gss_pipe[vers]->pipe;
548         INIT_LIST_HEAD(&gss_msg->list);
549         rpc_init_wait_queue(&gss_msg->rpc_waitqueue, "RPCSEC_GSS upcall waitq");
550         init_waitqueue_head(&gss_msg->waitqueue);
551         refcount_set(&gss_msg->count, 1);
552         gss_msg->uid = uid;
553         gss_msg->auth = gss_auth;
554         kref_get(&gss_auth->kref);
555         if (service_name) {
556                 gss_msg->service_name = kstrdup_const(service_name, GFP_NOFS);
557                 if (!gss_msg->service_name) {
558                         err = -ENOMEM;
559                         goto err_put_pipe_version;
560                 }
561         }
562         return gss_msg;
563 err_put_pipe_version:
564         put_pipe_version(gss_auth->net);
565 err_free_msg:
566         kfree(gss_msg);
567 err:
568         return ERR_PTR(err);
569 }
570 
571 static struct gss_upcall_msg *
572 gss_setup_upcall(struct gss_auth *gss_auth, struct rpc_cred *cred)
573 {
574         struct gss_cred *gss_cred = container_of(cred,
575                         struct gss_cred, gc_base);
576         struct gss_upcall_msg *gss_new, *gss_msg;
577         kuid_t uid = cred->cr_cred->fsuid;
578 
579         gss_new = gss_alloc_msg(gss_auth, uid, gss_cred->gc_principal);
580         if (IS_ERR(gss_new))
581                 return gss_new;
582         gss_msg = gss_add_msg(gss_new);
583         if (gss_msg == gss_new) {
584                 int res;
585                 refcount_inc(&gss_msg->count);
586                 res = rpc_queue_upcall(gss_new->pipe, &gss_new->msg);
587                 if (res) {
588                         gss_unhash_msg(gss_new);
589                         refcount_dec(&gss_msg->count);
590                         gss_release_msg(gss_new);
591                         gss_msg = ERR_PTR(res);
592                 }
593         } else
594                 gss_release_msg(gss_new);
595         return gss_msg;
596 }
597 
598 static void warn_gssd(void)
599 {
600         dprintk("AUTH_GSS upcall failed. Please check user daemon is running.\n");
601 }
602 
603 static inline int
604 gss_refresh_upcall(struct rpc_task *task)
605 {
606         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
607         struct gss_auth *gss_auth = container_of(cred->cr_auth,
608                         struct gss_auth, rpc_auth);
609         struct gss_cred *gss_cred = container_of(cred,
610                         struct gss_cred, gc_base);
611         struct gss_upcall_msg *gss_msg;
612         struct rpc_pipe *pipe;
613         int err = 0;
614 
615         gss_msg = gss_setup_upcall(gss_auth, cred);
616         if (PTR_ERR(gss_msg) == -EAGAIN) {
617                 /* XXX: warning on the first, under the assumption we
618                  * shouldn't normally hit this case on a refresh. */
619                 warn_gssd();
620                 rpc_sleep_on_timeout(&pipe_version_rpc_waitqueue,
621                                 task, NULL, jiffies + (15 * HZ));
622                 err = -EAGAIN;
623                 goto out;
624         }
625         if (IS_ERR(gss_msg)) {
626                 err = PTR_ERR(gss_msg);
627                 goto out;
628         }
629         pipe = gss_msg->pipe;
630         spin_lock(&pipe->lock);
631         if (gss_cred->gc_upcall != NULL)
632                 rpc_sleep_on(&gss_cred->gc_upcall->rpc_waitqueue, task, NULL);
633         else if (gss_msg->ctx == NULL && gss_msg->msg.errno >= 0) {
634                 gss_cred->gc_upcall = gss_msg;
635                 /* gss_upcall_callback will release the reference to gss_upcall_msg */
636                 refcount_inc(&gss_msg->count);
637                 rpc_sleep_on(&gss_msg->rpc_waitqueue, task, gss_upcall_callback);
638         } else {
639                 gss_handle_downcall_result(gss_cred, gss_msg);
640                 err = gss_msg->msg.errno;
641         }
642         spin_unlock(&pipe->lock);
643         gss_release_msg(gss_msg);
644 out:
645         trace_rpcgss_upcall_result(from_kuid(&init_user_ns,
646                                              cred->cr_cred->fsuid), err);
647         return err;
648 }
649 
650 static inline int
651 gss_create_upcall(struct gss_auth *gss_auth, struct gss_cred *gss_cred)
652 {
653         struct net *net = gss_auth->net;
654         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
655         struct rpc_pipe *pipe;
656         struct rpc_cred *cred = &gss_cred->gc_base;
657         struct gss_upcall_msg *gss_msg;
658         DEFINE_WAIT(wait);
659         int err;
660 
661 retry:
662         err = 0;
663         /* if gssd is down, just skip upcalling altogether */
664         if (!gssd_running(net)) {
665                 warn_gssd();
666                 err = -EACCES;
667                 goto out;
668         }
669         gss_msg = gss_setup_upcall(gss_auth, cred);
670         if (PTR_ERR(gss_msg) == -EAGAIN) {
671                 err = wait_event_interruptible_timeout(pipe_version_waitqueue,
672                                 sn->pipe_version >= 0, 15 * HZ);
673                 if (sn->pipe_version < 0) {
674                         warn_gssd();
675                         err = -EACCES;
676                 }
677                 if (err < 0)
678                         goto out;
679                 goto retry;
680         }
681         if (IS_ERR(gss_msg)) {
682                 err = PTR_ERR(gss_msg);
683                 goto out;
684         }
685         pipe = gss_msg->pipe;
686         for (;;) {
687                 prepare_to_wait(&gss_msg->waitqueue, &wait, TASK_KILLABLE);
688                 spin_lock(&pipe->lock);
689                 if (gss_msg->ctx != NULL || gss_msg->msg.errno < 0) {
690                         break;
691                 }
692                 spin_unlock(&pipe->lock);
693                 if (fatal_signal_pending(current)) {
694                         err = -ERESTARTSYS;
695                         goto out_intr;
696                 }
697                 schedule();
698         }
699         if (gss_msg->ctx)
700                 gss_cred_set_ctx(cred, gss_msg->ctx);
701         else
702                 err = gss_msg->msg.errno;
703         spin_unlock(&pipe->lock);
704 out_intr:
705         finish_wait(&gss_msg->waitqueue, &wait);
706         gss_release_msg(gss_msg);
707 out:
708         trace_rpcgss_upcall_result(from_kuid(&init_user_ns,
709                                              cred->cr_cred->fsuid), err);
710         return err;
711 }
712 
713 #define MSG_BUF_MAXSIZE 1024
714 
715 static ssize_t
716 gss_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
717 {
718         const void *p, *end;
719         void *buf;
720         struct gss_upcall_msg *gss_msg;
721         struct rpc_pipe *pipe = RPC_I(file_inode(filp))->pipe;
722         struct gss_cl_ctx *ctx;
723         uid_t id;
724         kuid_t uid;
725         ssize_t err = -EFBIG;
726 
727         if (mlen > MSG_BUF_MAXSIZE)
728                 goto out;
729         err = -ENOMEM;
730         buf = kmalloc(mlen, GFP_NOFS);
731         if (!buf)
732                 goto out;
733 
734         err = -EFAULT;
735         if (copy_from_user(buf, src, mlen))
736                 goto err;
737 
738         end = (const void *)((char *)buf + mlen);
739         p = simple_get_bytes(buf, end, &id, sizeof(id));
740         if (IS_ERR(p)) {
741                 err = PTR_ERR(p);
742                 goto err;
743         }
744 
745         uid = make_kuid(current_user_ns(), id);
746         if (!uid_valid(uid)) {
747                 err = -EINVAL;
748                 goto err;
749         }
750 
751         err = -ENOMEM;
752         ctx = gss_alloc_context();
753         if (ctx == NULL)
754                 goto err;
755 
756         err = -ENOENT;
757         /* Find a matching upcall */
758         spin_lock(&pipe->lock);
759         gss_msg = __gss_find_upcall(pipe, uid, NULL);
760         if (gss_msg == NULL) {
761                 spin_unlock(&pipe->lock);
762                 goto err_put_ctx;
763         }
764         list_del_init(&gss_msg->list);
765         spin_unlock(&pipe->lock);
766 
767         p = gss_fill_context(p, end, ctx, gss_msg->auth->mech);
768         if (IS_ERR(p)) {
769                 err = PTR_ERR(p);
770                 switch (err) {
771                 case -EACCES:
772                 case -EKEYEXPIRED:
773                         gss_msg->msg.errno = err;
774                         err = mlen;
775                         break;
776                 case -EFAULT:
777                 case -ENOMEM:
778                 case -EINVAL:
779                 case -ENOSYS:
780                         gss_msg->msg.errno = -EAGAIN;
781                         break;
782                 default:
783                         printk(KERN_CRIT "%s: bad return from "
784                                 "gss_fill_context: %zd\n", __func__, err);
785                         gss_msg->msg.errno = -EIO;
786                 }
787                 goto err_release_msg;
788         }
789         gss_msg->ctx = gss_get_ctx(ctx);
790         err = mlen;
791 
792 err_release_msg:
793         spin_lock(&pipe->lock);
794         __gss_unhash_msg(gss_msg);
795         spin_unlock(&pipe->lock);
796         gss_release_msg(gss_msg);
797 err_put_ctx:
798         gss_put_ctx(ctx);
799 err:
800         kfree(buf);
801 out:
802         return err;
803 }
804 
805 static int gss_pipe_open(struct inode *inode, int new_version)
806 {
807         struct net *net = inode->i_sb->s_fs_info;
808         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
809         int ret = 0;
810 
811         spin_lock(&pipe_version_lock);
812         if (sn->pipe_version < 0) {
813                 /* First open of any gss pipe determines the version: */
814                 sn->pipe_version = new_version;
815                 rpc_wake_up(&pipe_version_rpc_waitqueue);
816                 wake_up(&pipe_version_waitqueue);
817         } else if (sn->pipe_version != new_version) {
818                 /* Trying to open a pipe of a different version */
819                 ret = -EBUSY;
820                 goto out;
821         }
822         atomic_inc(&sn->pipe_users);
823 out:
824         spin_unlock(&pipe_version_lock);
825         return ret;
826 
827 }
828 
829 static int gss_pipe_open_v0(struct inode *inode)
830 {
831         return gss_pipe_open(inode, 0);
832 }
833 
834 static int gss_pipe_open_v1(struct inode *inode)
835 {
836         return gss_pipe_open(inode, 1);
837 }
838 
839 static void
840 gss_pipe_release(struct inode *inode)
841 {
842         struct net *net = inode->i_sb->s_fs_info;
843         struct rpc_pipe *pipe = RPC_I(inode)->pipe;
844         struct gss_upcall_msg *gss_msg;
845 
846 restart:
847         spin_lock(&pipe->lock);
848         list_for_each_entry(gss_msg, &pipe->in_downcall, list) {
849 
850                 if (!list_empty(&gss_msg->msg.list))
851                         continue;
852                 gss_msg->msg.errno = -EPIPE;
853                 refcount_inc(&gss_msg->count);
854                 __gss_unhash_msg(gss_msg);
855                 spin_unlock(&pipe->lock);
856                 gss_release_msg(gss_msg);
857                 goto restart;
858         }
859         spin_unlock(&pipe->lock);
860 
861         put_pipe_version(net);
862 }
863 
864 static void
865 gss_pipe_destroy_msg(struct rpc_pipe_msg *msg)
866 {
867         struct gss_upcall_msg *gss_msg = container_of(msg, struct gss_upcall_msg, msg);
868 
869         if (msg->errno < 0) {
870                 refcount_inc(&gss_msg->count);
871                 gss_unhash_msg(gss_msg);
872                 if (msg->errno == -ETIMEDOUT)
873                         warn_gssd();
874                 gss_release_msg(gss_msg);
875         }
876         gss_release_msg(gss_msg);
877 }
878 
879 static void gss_pipe_dentry_destroy(struct dentry *dir,
880                 struct rpc_pipe_dir_object *pdo)
881 {
882         struct gss_pipe *gss_pipe = pdo->pdo_data;
883         struct rpc_pipe *pipe = gss_pipe->pipe;
884 
885         if (pipe->dentry != NULL) {
886                 rpc_unlink(pipe->dentry);
887                 pipe->dentry = NULL;
888         }
889 }
890 
891 static int gss_pipe_dentry_create(struct dentry *dir,
892                 struct rpc_pipe_dir_object *pdo)
893 {
894         struct gss_pipe *p = pdo->pdo_data;
895         struct dentry *dentry;
896 
897         dentry = rpc_mkpipe_dentry(dir, p->name, p->clnt, p->pipe);
898         if (IS_ERR(dentry))
899                 return PTR_ERR(dentry);
900         p->pipe->dentry = dentry;
901         return 0;
902 }
903 
904 static const struct rpc_pipe_dir_object_ops gss_pipe_dir_object_ops = {
905         .create = gss_pipe_dentry_create,
906         .destroy = gss_pipe_dentry_destroy,
907 };
908 
909 static struct gss_pipe *gss_pipe_alloc(struct rpc_clnt *clnt,
910                 const char *name,
911                 const struct rpc_pipe_ops *upcall_ops)
912 {
913         struct gss_pipe *p;
914         int err = -ENOMEM;
915 
916         p = kmalloc(sizeof(*p), GFP_KERNEL);
917         if (p == NULL)
918                 goto err;
919         p->pipe = rpc_mkpipe_data(upcall_ops, RPC_PIPE_WAIT_FOR_OPEN);
920         if (IS_ERR(p->pipe)) {
921                 err = PTR_ERR(p->pipe);
922                 goto err_free_gss_pipe;
923         }
924         p->name = name;
925         p->clnt = clnt;
926         kref_init(&p->kref);
927         rpc_init_pipe_dir_object(&p->pdo,
928                         &gss_pipe_dir_object_ops,
929                         p);
930         return p;
931 err_free_gss_pipe:
932         kfree(p);
933 err:
934         return ERR_PTR(err);
935 }
936 
937 struct gss_alloc_pdo {
938         struct rpc_clnt *clnt;
939         const char *name;
940         const struct rpc_pipe_ops *upcall_ops;
941 };
942 
943 static int gss_pipe_match_pdo(struct rpc_pipe_dir_object *pdo, void *data)
944 {
945         struct gss_pipe *gss_pipe;
946         struct gss_alloc_pdo *args = data;
947 
948         if (pdo->pdo_ops != &gss_pipe_dir_object_ops)
949                 return 0;
950         gss_pipe = container_of(pdo, struct gss_pipe, pdo);
951         if (strcmp(gss_pipe->name, args->name) != 0)
952                 return 0;
953         if (!kref_get_unless_zero(&gss_pipe->kref))
954                 return 0;
955         return 1;
956 }
957 
958 static struct rpc_pipe_dir_object *gss_pipe_alloc_pdo(void *data)
959 {
960         struct gss_pipe *gss_pipe;
961         struct gss_alloc_pdo *args = data;
962 
963         gss_pipe = gss_pipe_alloc(args->clnt, args->name, args->upcall_ops);
964         if (!IS_ERR(gss_pipe))
965                 return &gss_pipe->pdo;
966         return NULL;
967 }
968 
969 static struct gss_pipe *gss_pipe_get(struct rpc_clnt *clnt,
970                 const char *name,
971                 const struct rpc_pipe_ops *upcall_ops)
972 {
973         struct net *net = rpc_net_ns(clnt);
974         struct rpc_pipe_dir_object *pdo;
975         struct gss_alloc_pdo args = {
976                 .clnt = clnt,
977                 .name = name,
978                 .upcall_ops = upcall_ops,
979         };
980 
981         pdo = rpc_find_or_alloc_pipe_dir_object(net,
982                         &clnt->cl_pipedir_objects,
983                         gss_pipe_match_pdo,
984                         gss_pipe_alloc_pdo,
985                         &args);
986         if (pdo != NULL)
987                 return container_of(pdo, struct gss_pipe, pdo);
988         return ERR_PTR(-ENOMEM);
989 }
990 
991 static void __gss_pipe_free(struct gss_pipe *p)
992 {
993         struct rpc_clnt *clnt = p->clnt;
994         struct net *net = rpc_net_ns(clnt);
995 
996         rpc_remove_pipe_dir_object(net,
997                         &clnt->cl_pipedir_objects,
998                         &p->pdo);
999         rpc_destroy_pipe_data(p->pipe);
1000         kfree(p);
1001 }
1002 
1003 static void __gss_pipe_release(struct kref *kref)
1004 {
1005         struct gss_pipe *p = container_of(kref, struct gss_pipe, kref);
1006 
1007         __gss_pipe_free(p);
1008 }
1009 
1010 static void gss_pipe_free(struct gss_pipe *p)
1011 {
1012         if (p != NULL)
1013                 kref_put(&p->kref, __gss_pipe_release);
1014 }
1015 
1016 /*
1017  * NOTE: we have the opportunity to use different
1018  * parameters based on the input flavor (which must be a pseudoflavor)
1019  */
1020 static struct gss_auth *
1021 gss_create_new(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
1022 {
1023         rpc_authflavor_t flavor = args->pseudoflavor;
1024         struct gss_auth *gss_auth;
1025         struct gss_pipe *gss_pipe;
1026         struct rpc_auth * auth;
1027         int err = -ENOMEM; /* XXX? */
1028 
1029         if (!try_module_get(THIS_MODULE))
1030                 return ERR_PTR(err);
1031         if (!(gss_auth = kmalloc(sizeof(*gss_auth), GFP_KERNEL)))
1032                 goto out_dec;
1033         INIT_HLIST_NODE(&gss_auth->hash);
1034         gss_auth->target_name = NULL;
1035         if (args->target_name) {
1036                 gss_auth->target_name = kstrdup(args->target_name, GFP_KERNEL);
1037                 if (gss_auth->target_name == NULL)
1038                         goto err_free;
1039         }
1040         gss_auth->client = clnt;
1041         gss_auth->net = get_net(rpc_net_ns(clnt));
1042         err = -EINVAL;
1043         gss_auth->mech = gss_mech_get_by_pseudoflavor(flavor);
1044         if (!gss_auth->mech)
1045                 goto err_put_net;
1046         gss_auth->service = gss_pseudoflavor_to_service(gss_auth->mech, flavor);
1047         if (gss_auth->service == 0)
1048                 goto err_put_mech;
1049         if (!gssd_running(gss_auth->net))
1050                 goto err_put_mech;
1051         auth = &gss_auth->rpc_auth;
1052         auth->au_cslack = GSS_CRED_SLACK >> 2;
1053         auth->au_rslack = GSS_VERF_SLACK >> 2;
1054         auth->au_verfsize = GSS_VERF_SLACK >> 2;
1055         auth->au_ralign = GSS_VERF_SLACK >> 2;
1056         auth->au_flags = 0;
1057         auth->au_ops = &authgss_ops;
1058         auth->au_flavor = flavor;
1059         if (gss_pseudoflavor_to_datatouch(gss_auth->mech, flavor))
1060                 auth->au_flags |= RPCAUTH_AUTH_DATATOUCH;
1061         refcount_set(&auth->au_count, 1);
1062         kref_init(&gss_auth->kref);
1063 
1064         err = rpcauth_init_credcache(auth);
1065         if (err)
1066                 goto err_put_mech;
1067         /*
1068          * Note: if we created the old pipe first, then someone who
1069          * examined the directory at the right moment might conclude
1070          * that we supported only the old pipe.  So we instead create
1071          * the new pipe first.
1072          */
1073         gss_pipe = gss_pipe_get(clnt, "gssd", &gss_upcall_ops_v1);
1074         if (IS_ERR(gss_pipe)) {
1075                 err = PTR_ERR(gss_pipe);
1076                 goto err_destroy_credcache;
1077         }
1078         gss_auth->gss_pipe[1] = gss_pipe;
1079 
1080         gss_pipe = gss_pipe_get(clnt, gss_auth->mech->gm_name,
1081                         &gss_upcall_ops_v0);
1082         if (IS_ERR(gss_pipe)) {
1083                 err = PTR_ERR(gss_pipe);
1084                 goto err_destroy_pipe_1;
1085         }
1086         gss_auth->gss_pipe[0] = gss_pipe;
1087 
1088         return gss_auth;
1089 err_destroy_pipe_1:
1090         gss_pipe_free(gss_auth->gss_pipe[1]);
1091 err_destroy_credcache:
1092         rpcauth_destroy_credcache(auth);
1093 err_put_mech:
1094         gss_mech_put(gss_auth->mech);
1095 err_put_net:
1096         put_net(gss_auth->net);
1097 err_free:
1098         kfree(gss_auth->target_name);
1099         kfree(gss_auth);
1100 out_dec:
1101         module_put(THIS_MODULE);
1102         trace_rpcgss_createauth(flavor, err);
1103         return ERR_PTR(err);
1104 }
1105 
1106 static void
1107 gss_free(struct gss_auth *gss_auth)
1108 {
1109         gss_pipe_free(gss_auth->gss_pipe[0]);
1110         gss_pipe_free(gss_auth->gss_pipe[1]);
1111         gss_mech_put(gss_auth->mech);
1112         put_net(gss_auth->net);
1113         kfree(gss_auth->target_name);
1114 
1115         kfree(gss_auth);
1116         module_put(THIS_MODULE);
1117 }
1118 
1119 static void
1120 gss_free_callback(struct kref *kref)
1121 {
1122         struct gss_auth *gss_auth = container_of(kref, struct gss_auth, kref);
1123 
1124         gss_free(gss_auth);
1125 }
1126 
1127 static void
1128 gss_put_auth(struct gss_auth *gss_auth)
1129 {
1130         kref_put(&gss_auth->kref, gss_free_callback);
1131 }
1132 
1133 static void
1134 gss_destroy(struct rpc_auth *auth)
1135 {
1136         struct gss_auth *gss_auth = container_of(auth,
1137                         struct gss_auth, rpc_auth);
1138 
1139         if (hash_hashed(&gss_auth->hash)) {
1140                 spin_lock(&gss_auth_hash_lock);
1141                 hash_del(&gss_auth->hash);
1142                 spin_unlock(&gss_auth_hash_lock);
1143         }
1144 
1145         gss_pipe_free(gss_auth->gss_pipe[0]);
1146         gss_auth->gss_pipe[0] = NULL;
1147         gss_pipe_free(gss_auth->gss_pipe[1]);
1148         gss_auth->gss_pipe[1] = NULL;
1149         rpcauth_destroy_credcache(auth);
1150 
1151         gss_put_auth(gss_auth);
1152 }
1153 
1154 /*
1155  * Auths may be shared between rpc clients that were cloned from a
1156  * common client with the same xprt, if they also share the flavor and
1157  * target_name.
1158  *
1159  * The auth is looked up from the oldest parent sharing the same
1160  * cl_xprt, and the auth itself references only that common parent
1161  * (which is guaranteed to last as long as any of its descendants).
1162  */
1163 static struct gss_auth *
1164 gss_auth_find_or_add_hashed(const struct rpc_auth_create_args *args,
1165                 struct rpc_clnt *clnt,
1166                 struct gss_auth *new)
1167 {
1168         struct gss_auth *gss_auth;
1169         unsigned long hashval = (unsigned long)clnt;
1170 
1171         spin_lock(&gss_auth_hash_lock);
1172         hash_for_each_possible(gss_auth_hash_table,
1173                         gss_auth,
1174                         hash,
1175                         hashval) {
1176                 if (gss_auth->client != clnt)
1177                         continue;
1178                 if (gss_auth->rpc_auth.au_flavor != args->pseudoflavor)
1179                         continue;
1180                 if (gss_auth->target_name != args->target_name) {
1181                         if (gss_auth->target_name == NULL)
1182                                 continue;
1183                         if (args->target_name == NULL)
1184                                 continue;
1185                         if (strcmp(gss_auth->target_name, args->target_name))
1186                                 continue;
1187                 }
1188                 if (!refcount_inc_not_zero(&gss_auth->rpc_auth.au_count))
1189                         continue;
1190                 goto out;
1191         }
1192         if (new)
1193                 hash_add(gss_auth_hash_table, &new->hash, hashval);
1194         gss_auth = new;
1195 out:
1196         spin_unlock(&gss_auth_hash_lock);
1197         return gss_auth;
1198 }
1199 
1200 static struct gss_auth *
1201 gss_create_hashed(const struct rpc_auth_create_args *args,
1202                   struct rpc_clnt *clnt)
1203 {
1204         struct gss_auth *gss_auth;
1205         struct gss_auth *new;
1206 
1207         gss_auth = gss_auth_find_or_add_hashed(args, clnt, NULL);
1208         if (gss_auth != NULL)
1209                 goto out;
1210         new = gss_create_new(args, clnt);
1211         if (IS_ERR(new))
1212                 return new;
1213         gss_auth = gss_auth_find_or_add_hashed(args, clnt, new);
1214         if (gss_auth != new)
1215                 gss_destroy(&new->rpc_auth);
1216 out:
1217         return gss_auth;
1218 }
1219 
1220 static struct rpc_auth *
1221 gss_create(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
1222 {
1223         struct gss_auth *gss_auth;
1224         struct rpc_xprt_switch *xps = rcu_access_pointer(clnt->cl_xpi.xpi_xpswitch);
1225 
1226         while (clnt != clnt->cl_parent) {
1227                 struct rpc_clnt *parent = clnt->cl_parent;
1228                 /* Find the original parent for this transport */
1229                 if (rcu_access_pointer(parent->cl_xpi.xpi_xpswitch) != xps)
1230                         break;
1231                 clnt = parent;
1232         }
1233 
1234         gss_auth = gss_create_hashed(args, clnt);
1235         if (IS_ERR(gss_auth))
1236                 return ERR_CAST(gss_auth);
1237         return &gss_auth->rpc_auth;
1238 }
1239 
1240 static struct gss_cred *
1241 gss_dup_cred(struct gss_auth *gss_auth, struct gss_cred *gss_cred)
1242 {
1243         struct gss_cred *new;
1244 
1245         /* Make a copy of the cred so that we can reference count it */
1246         new = kzalloc(sizeof(*gss_cred), GFP_NOFS);
1247         if (new) {
1248                 struct auth_cred acred = {
1249                         .cred = gss_cred->gc_base.cr_cred,
1250                 };
1251                 struct gss_cl_ctx *ctx =
1252                         rcu_dereference_protected(gss_cred->gc_ctx, 1);
1253 
1254                 rpcauth_init_cred(&new->gc_base, &acred,
1255                                 &gss_auth->rpc_auth,
1256                                 &gss_nullops);
1257                 new->gc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
1258                 new->gc_service = gss_cred->gc_service;
1259                 new->gc_principal = gss_cred->gc_principal;
1260                 kref_get(&gss_auth->kref);
1261                 rcu_assign_pointer(new->gc_ctx, ctx);
1262                 gss_get_ctx(ctx);
1263         }
1264         return new;
1265 }
1266 
1267 /*
1268  * gss_send_destroy_context will cause the RPCSEC_GSS to send a NULL RPC call
1269  * to the server with the GSS control procedure field set to
1270  * RPC_GSS_PROC_DESTROY. This should normally cause the server to release
1271  * all RPCSEC_GSS state associated with that context.
1272  */
1273 static void
1274 gss_send_destroy_context(struct rpc_cred *cred)
1275 {
1276         struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
1277         struct gss_auth *gss_auth = container_of(cred->cr_auth, struct gss_auth, rpc_auth);
1278         struct gss_cl_ctx *ctx = rcu_dereference_protected(gss_cred->gc_ctx, 1);
1279         struct gss_cred *new;
1280         struct rpc_task *task;
1281 
1282         new = gss_dup_cred(gss_auth, gss_cred);
1283         if (new) {
1284                 ctx->gc_proc = RPC_GSS_PROC_DESTROY;
1285 
1286                 task = rpc_call_null(gss_auth->client, &new->gc_base,
1287                                 RPC_TASK_ASYNC|RPC_TASK_SOFT);
1288                 if (!IS_ERR(task))
1289                         rpc_put_task(task);
1290 
1291                 put_rpccred(&new->gc_base);
1292         }
1293 }
1294 
1295 /* gss_destroy_cred (and gss_free_ctx) are used to clean up after failure
1296  * to create a new cred or context, so they check that things have been
1297  * allocated before freeing them. */
1298 static void
1299 gss_do_free_ctx(struct gss_cl_ctx *ctx)
1300 {
1301         gss_delete_sec_context(&ctx->gc_gss_ctx);
1302         kfree(ctx->gc_wire_ctx.data);
1303         kfree(ctx->gc_acceptor.data);
1304         kfree(ctx);
1305 }
1306 
1307 static void
1308 gss_free_ctx_callback(struct rcu_head *head)
1309 {
1310         struct gss_cl_ctx *ctx = container_of(head, struct gss_cl_ctx, gc_rcu);
1311         gss_do_free_ctx(ctx);
1312 }
1313 
1314 static void
1315 gss_free_ctx(struct gss_cl_ctx *ctx)
1316 {
1317         call_rcu(&ctx->gc_rcu, gss_free_ctx_callback);
1318 }
1319 
1320 static void
1321 gss_free_cred(struct gss_cred *gss_cred)
1322 {
1323         kfree(gss_cred);
1324 }
1325 
1326 static void
1327 gss_free_cred_callback(struct rcu_head *head)
1328 {
1329         struct gss_cred *gss_cred = container_of(head, struct gss_cred, gc_base.cr_rcu);
1330         gss_free_cred(gss_cred);
1331 }
1332 
1333 static void
1334 gss_destroy_nullcred(struct rpc_cred *cred)
1335 {
1336         struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
1337         struct gss_auth *gss_auth = container_of(cred->cr_auth, struct gss_auth, rpc_auth);
1338         struct gss_cl_ctx *ctx = rcu_dereference_protected(gss_cred->gc_ctx, 1);
1339 
1340         RCU_INIT_POINTER(gss_cred->gc_ctx, NULL);
1341         put_cred(cred->cr_cred);
1342         call_rcu(&cred->cr_rcu, gss_free_cred_callback);
1343         if (ctx)
1344                 gss_put_ctx(ctx);
1345         gss_put_auth(gss_auth);
1346 }
1347 
1348 static void
1349 gss_destroy_cred(struct rpc_cred *cred)
1350 {
1351 
1352         if (test_and_clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0)
1353                 gss_send_destroy_context(cred);
1354         gss_destroy_nullcred(cred);
1355 }
1356 
1357 static int
1358 gss_hash_cred(struct auth_cred *acred, unsigned int hashbits)
1359 {
1360         return hash_64(from_kuid(&init_user_ns, acred->cred->fsuid), hashbits);
1361 }
1362 
1363 /*
1364  * Lookup RPCSEC_GSS cred for the current process
1365  */
1366 static struct rpc_cred *
1367 gss_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
1368 {
1369         return rpcauth_lookup_credcache(auth, acred, flags, GFP_NOFS);
1370 }
1371 
1372 static struct rpc_cred *
1373 gss_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags, gfp_t gfp)
1374 {
1375         struct gss_auth *gss_auth = container_of(auth, struct gss_auth, rpc_auth);
1376         struct gss_cred *cred = NULL;
1377         int err = -ENOMEM;
1378 
1379         if (!(cred = kzalloc(sizeof(*cred), gfp)))
1380                 goto out_err;
1381 
1382         rpcauth_init_cred(&cred->gc_base, acred, auth, &gss_credops);
1383         /*
1384          * Note: in order to force a call to call_refresh(), we deliberately
1385          * fail to flag the credential as RPCAUTH_CRED_UPTODATE.
1386          */
1387         cred->gc_base.cr_flags = 1UL << RPCAUTH_CRED_NEW;
1388         cred->gc_service = gss_auth->service;
1389         cred->gc_principal = acred->principal;
1390         kref_get(&gss_auth->kref);
1391         return &cred->gc_base;
1392 
1393 out_err:
1394         return ERR_PTR(err);
1395 }
1396 
1397 static int
1398 gss_cred_init(struct rpc_auth *auth, struct rpc_cred *cred)
1399 {
1400         struct gss_auth *gss_auth = container_of(auth, struct gss_auth, rpc_auth);
1401         struct gss_cred *gss_cred = container_of(cred,struct gss_cred, gc_base);
1402         int err;
1403 
1404         do {
1405                 err = gss_create_upcall(gss_auth, gss_cred);
1406         } while (err == -EAGAIN);
1407         return err;
1408 }
1409 
1410 static char *
1411 gss_stringify_acceptor(struct rpc_cred *cred)
1412 {
1413         char *string = NULL;
1414         struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
1415         struct gss_cl_ctx *ctx;
1416         unsigned int len;
1417         struct xdr_netobj *acceptor;
1418 
1419         rcu_read_lock();
1420         ctx = rcu_dereference(gss_cred->gc_ctx);
1421         if (!ctx)
1422                 goto out;
1423 
1424         len = ctx->gc_acceptor.len;
1425         rcu_read_unlock();
1426 
1427         /* no point if there's no string */
1428         if (!len)
1429                 return NULL;
1430 realloc:
1431         string = kmalloc(len + 1, GFP_KERNEL);
1432         if (!string)
1433                 return NULL;
1434 
1435         rcu_read_lock();
1436         ctx = rcu_dereference(gss_cred->gc_ctx);
1437 
1438         /* did the ctx disappear or was it replaced by one with no acceptor? */
1439         if (!ctx || !ctx->gc_acceptor.len) {
1440                 kfree(string);
1441                 string = NULL;
1442                 goto out;
1443         }
1444 
1445         acceptor = &ctx->gc_acceptor;
1446 
1447         /*
1448          * Did we find a new acceptor that's longer than the original? Allocate
1449          * a longer buffer and try again.
1450          */
1451         if (len < acceptor->len) {
1452                 len = acceptor->len;
1453                 rcu_read_unlock();
1454                 kfree(string);
1455                 goto realloc;
1456         }
1457 
1458         memcpy(string, acceptor->data, acceptor->len);
1459         string[acceptor->len] = '\0';
1460 out:
1461         rcu_read_unlock();
1462         return string;
1463 }
1464 
1465 /*
1466  * Returns -EACCES if GSS context is NULL or will expire within the
1467  * timeout (miliseconds)
1468  */
1469 static int
1470 gss_key_timeout(struct rpc_cred *rc)
1471 {
1472         struct gss_cred *gss_cred = container_of(rc, struct gss_cred, gc_base);
1473         struct gss_cl_ctx *ctx;
1474         unsigned long timeout = jiffies + (gss_key_expire_timeo * HZ);
1475         int ret = 0;
1476 
1477         rcu_read_lock();
1478         ctx = rcu_dereference(gss_cred->gc_ctx);
1479         if (!ctx || time_after(timeout, ctx->gc_expiry))
1480                 ret = -EACCES;
1481         rcu_read_unlock();
1482 
1483         return ret;
1484 }
1485 
1486 static int
1487 gss_match(struct auth_cred *acred, struct rpc_cred *rc, int flags)
1488 {
1489         struct gss_cred *gss_cred = container_of(rc, struct gss_cred, gc_base);
1490         struct gss_cl_ctx *ctx;
1491         int ret;
1492 
1493         if (test_bit(RPCAUTH_CRED_NEW, &rc->cr_flags))
1494                 goto out;
1495         /* Don't match with creds that have expired. */
1496         rcu_read_lock();
1497         ctx = rcu_dereference(gss_cred->gc_ctx);
1498         if (!ctx || time_after(jiffies, ctx->gc_expiry)) {
1499                 rcu_read_unlock();
1500                 return 0;
1501         }
1502         rcu_read_unlock();
1503         if (!test_bit(RPCAUTH_CRED_UPTODATE, &rc->cr_flags))
1504                 return 0;
1505 out:
1506         if (acred->principal != NULL) {
1507                 if (gss_cred->gc_principal == NULL)
1508                         return 0;
1509                 ret = strcmp(acred->principal, gss_cred->gc_principal) == 0;
1510         } else {
1511                 if (gss_cred->gc_principal != NULL)
1512                         return 0;
1513                 ret = uid_eq(rc->cr_cred->fsuid, acred->cred->fsuid);
1514         }
1515         return ret;
1516 }
1517 
1518 /*
1519  * Marshal credentials.
1520  *
1521  * The expensive part is computing the verifier. We can't cache a
1522  * pre-computed version of the verifier because the seqno, which
1523  * is different every time, is included in the MIC.
1524  */
1525 static int gss_marshal(struct rpc_task *task, struct xdr_stream *xdr)
1526 {
1527         struct rpc_rqst *req = task->tk_rqstp;
1528         struct rpc_cred *cred = req->rq_cred;
1529         struct gss_cred *gss_cred = container_of(cred, struct gss_cred,
1530                                                  gc_base);
1531         struct gss_cl_ctx       *ctx = gss_cred_get_ctx(cred);
1532         __be32          *p, *cred_len;
1533         u32             maj_stat = 0;
1534         struct xdr_netobj mic;
1535         struct kvec     iov;
1536         struct xdr_buf  verf_buf;
1537         int status;
1538 
1539         /* Credential */
1540 
1541         p = xdr_reserve_space(xdr, 7 * sizeof(*p) +
1542                               ctx->gc_wire_ctx.len);
1543         if (!p)
1544                 goto marshal_failed;
1545         *p++ = rpc_auth_gss;
1546         cred_len = p++;
1547 
1548         spin_lock(&ctx->gc_seq_lock);
1549         req->rq_seqno = (ctx->gc_seq < MAXSEQ) ? ctx->gc_seq++ : MAXSEQ;
1550         spin_unlock(&ctx->gc_seq_lock);
1551         if (req->rq_seqno == MAXSEQ)
1552                 goto expired;
1553         trace_rpcgss_seqno(task);
1554 
1555         *p++ = cpu_to_be32(RPC_GSS_VERSION);
1556         *p++ = cpu_to_be32(ctx->gc_proc);
1557         *p++ = cpu_to_be32(req->rq_seqno);
1558         *p++ = cpu_to_be32(gss_cred->gc_service);
1559         p = xdr_encode_netobj(p, &ctx->gc_wire_ctx);
1560         *cred_len = cpu_to_be32((p - (cred_len + 1)) << 2);
1561 
1562         /* Verifier */
1563 
1564         /* We compute the checksum for the verifier over the xdr-encoded bytes
1565          * starting with the xid and ending at the end of the credential: */
1566         iov.iov_base = req->rq_snd_buf.head[0].iov_base;
1567         iov.iov_len = (u8 *)p - (u8 *)iov.iov_base;
1568         xdr_buf_from_iov(&iov, &verf_buf);
1569 
1570         p = xdr_reserve_space(xdr, sizeof(*p));
1571         if (!p)
1572                 goto marshal_failed;
1573         *p++ = rpc_auth_gss;
1574         mic.data = (u8 *)(p + 1);
1575         maj_stat = gss_get_mic(ctx->gc_gss_ctx, &verf_buf, &mic);
1576         if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1577                 goto expired;
1578         else if (maj_stat != 0)
1579                 goto bad_mic;
1580         if (xdr_stream_encode_opaque_inline(xdr, (void **)&p, mic.len) < 0)
1581                 goto marshal_failed;
1582         status = 0;
1583 out:
1584         gss_put_ctx(ctx);
1585         return status;
1586 expired:
1587         clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1588         status = -EKEYEXPIRED;
1589         goto out;
1590 marshal_failed:
1591         status = -EMSGSIZE;
1592         goto out;
1593 bad_mic:
1594         trace_rpcgss_get_mic(task, maj_stat);
1595         status = -EIO;
1596         goto out;
1597 }
1598 
1599 static int gss_renew_cred(struct rpc_task *task)
1600 {
1601         struct rpc_cred *oldcred = task->tk_rqstp->rq_cred;
1602         struct gss_cred *gss_cred = container_of(oldcred,
1603                                                  struct gss_cred,
1604                                                  gc_base);
1605         struct rpc_auth *auth = oldcred->cr_auth;
1606         struct auth_cred acred = {
1607                 .cred = oldcred->cr_cred,
1608                 .principal = gss_cred->gc_principal,
1609         };
1610         struct rpc_cred *new;
1611 
1612         new = gss_lookup_cred(auth, &acred, RPCAUTH_LOOKUP_NEW);
1613         if (IS_ERR(new))
1614                 return PTR_ERR(new);
1615         task->tk_rqstp->rq_cred = new;
1616         put_rpccred(oldcred);
1617         return 0;
1618 }
1619 
1620 static int gss_cred_is_negative_entry(struct rpc_cred *cred)
1621 {
1622         if (test_bit(RPCAUTH_CRED_NEGATIVE, &cred->cr_flags)) {
1623                 unsigned long now = jiffies;
1624                 unsigned long begin, expire;
1625                 struct gss_cred *gss_cred;
1626 
1627                 gss_cred = container_of(cred, struct gss_cred, gc_base);
1628                 begin = gss_cred->gc_upcall_timestamp;
1629                 expire = begin + gss_expired_cred_retry_delay * HZ;
1630 
1631                 if (time_in_range_open(now, begin, expire))
1632                         return 1;
1633         }
1634         return 0;
1635 }
1636 
1637 /*
1638 * Refresh credentials. XXX - finish
1639 */
1640 static int
1641 gss_refresh(struct rpc_task *task)
1642 {
1643         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
1644         int ret = 0;
1645 
1646         if (gss_cred_is_negative_entry(cred))
1647                 return -EKEYEXPIRED;
1648 
1649         if (!test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags) &&
1650                         !test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags)) {
1651                 ret = gss_renew_cred(task);
1652                 if (ret < 0)
1653                         goto out;
1654                 cred = task->tk_rqstp->rq_cred;
1655         }
1656 
1657         if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags))
1658                 ret = gss_refresh_upcall(task);
1659 out:
1660         return ret;
1661 }
1662 
1663 /* Dummy refresh routine: used only when destroying the context */
1664 static int
1665 gss_refresh_null(struct rpc_task *task)
1666 {
1667         return 0;
1668 }
1669 
1670 static int
1671 gss_validate(struct rpc_task *task, struct xdr_stream *xdr)
1672 {
1673         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
1674         struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
1675         __be32          *p, *seq = NULL;
1676         struct kvec     iov;
1677         struct xdr_buf  verf_buf;
1678         struct xdr_netobj mic;
1679         u32             len, maj_stat;
1680         int             status;
1681 
1682         p = xdr_inline_decode(xdr, 2 * sizeof(*p));
1683         if (!p)
1684                 goto validate_failed;
1685         if (*p++ != rpc_auth_gss)
1686                 goto validate_failed;
1687         len = be32_to_cpup(p);
1688         if (len > RPC_MAX_AUTH_SIZE)
1689                 goto validate_failed;
1690         p = xdr_inline_decode(xdr, len);
1691         if (!p)
1692                 goto validate_failed;
1693 
1694         seq = kmalloc(4, GFP_NOFS);
1695         if (!seq)
1696                 goto validate_failed;
1697         *seq = cpu_to_be32(task->tk_rqstp->rq_seqno);
1698         iov.iov_base = seq;
1699         iov.iov_len = 4;
1700         xdr_buf_from_iov(&iov, &verf_buf);
1701         mic.data = (u8 *)p;
1702         mic.len = len;
1703         maj_stat = gss_verify_mic(ctx->gc_gss_ctx, &verf_buf, &mic);
1704         if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1705                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1706         if (maj_stat)
1707                 goto bad_mic;
1708 
1709         /* We leave it to unwrap to calculate au_rslack. For now we just
1710          * calculate the length of the verifier: */
1711         cred->cr_auth->au_verfsize = XDR_QUADLEN(len) + 2;
1712         status = 0;
1713 out:
1714         gss_put_ctx(ctx);
1715         kfree(seq);
1716         return status;
1717 
1718 validate_failed:
1719         status = -EIO;
1720         goto out;
1721 bad_mic:
1722         trace_rpcgss_verify_mic(task, maj_stat);
1723         status = -EACCES;
1724         goto out;
1725 }
1726 
1727 static int gss_wrap_req_integ(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
1728                               struct rpc_task *task, struct xdr_stream *xdr)
1729 {
1730         struct rpc_rqst *rqstp = task->tk_rqstp;
1731         struct xdr_buf integ_buf, *snd_buf = &rqstp->rq_snd_buf;
1732         struct xdr_netobj mic;
1733         __be32 *p, *integ_len;
1734         u32 offset, maj_stat;
1735 
1736         p = xdr_reserve_space(xdr, 2 * sizeof(*p));
1737         if (!p)
1738                 goto wrap_failed;
1739         integ_len = p++;
1740         *p = cpu_to_be32(rqstp->rq_seqno);
1741 
1742         if (rpcauth_wrap_req_encode(task, xdr))
1743                 goto wrap_failed;
1744 
1745         offset = (u8 *)p - (u8 *)snd_buf->head[0].iov_base;
1746         if (xdr_buf_subsegment(snd_buf, &integ_buf,
1747                                 offset, snd_buf->len - offset))
1748                 goto wrap_failed;
1749         *integ_len = cpu_to_be32(integ_buf.len);
1750 
1751         p = xdr_reserve_space(xdr, 0);
1752         if (!p)
1753                 goto wrap_failed;
1754         mic.data = (u8 *)(p + 1);
1755         maj_stat = gss_get_mic(ctx->gc_gss_ctx, &integ_buf, &mic);
1756         if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1757                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1758         else if (maj_stat)
1759                 goto bad_mic;
1760         /* Check that the trailing MIC fit in the buffer, after the fact */
1761         if (xdr_stream_encode_opaque_inline(xdr, (void **)&p, mic.len) < 0)
1762                 goto wrap_failed;
1763         return 0;
1764 wrap_failed:
1765         return -EMSGSIZE;
1766 bad_mic:
1767         trace_rpcgss_get_mic(task, maj_stat);
1768         return -EIO;
1769 }
1770 
1771 static void
1772 priv_release_snd_buf(struct rpc_rqst *rqstp)
1773 {
1774         int i;
1775 
1776         for (i=0; i < rqstp->rq_enc_pages_num; i++)
1777                 __free_page(rqstp->rq_enc_pages[i]);
1778         kfree(rqstp->rq_enc_pages);
1779         rqstp->rq_release_snd_buf = NULL;
1780 }
1781 
1782 static int
1783 alloc_enc_pages(struct rpc_rqst *rqstp)
1784 {
1785         struct xdr_buf *snd_buf = &rqstp->rq_snd_buf;
1786         int first, last, i;
1787 
1788         if (rqstp->rq_release_snd_buf)
1789                 rqstp->rq_release_snd_buf(rqstp);
1790 
1791         if (snd_buf->page_len == 0) {
1792                 rqstp->rq_enc_pages_num = 0;
1793                 return 0;
1794         }
1795 
1796         first = snd_buf->page_base >> PAGE_SHIFT;
1797         last = (snd_buf->page_base + snd_buf->page_len - 1) >> PAGE_SHIFT;
1798         rqstp->rq_enc_pages_num = last - first + 1 + 1;
1799         rqstp->rq_enc_pages
1800                 = kmalloc_array(rqstp->rq_enc_pages_num,
1801                                 sizeof(struct page *),
1802                                 GFP_NOFS);
1803         if (!rqstp->rq_enc_pages)
1804                 goto out;
1805         for (i=0; i < rqstp->rq_enc_pages_num; i++) {
1806                 rqstp->rq_enc_pages[i] = alloc_page(GFP_NOFS);
1807                 if (rqstp->rq_enc_pages[i] == NULL)
1808                         goto out_free;
1809         }
1810         rqstp->rq_release_snd_buf = priv_release_snd_buf;
1811         return 0;
1812 out_free:
1813         rqstp->rq_enc_pages_num = i;
1814         priv_release_snd_buf(rqstp);
1815 out:
1816         return -EAGAIN;
1817 }
1818 
1819 static int gss_wrap_req_priv(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
1820                              struct rpc_task *task, struct xdr_stream *xdr)
1821 {
1822         struct rpc_rqst *rqstp = task->tk_rqstp;
1823         struct xdr_buf  *snd_buf = &rqstp->rq_snd_buf;
1824         u32             pad, offset, maj_stat;
1825         int             status;
1826         __be32          *p, *opaque_len;
1827         struct page     **inpages;
1828         int             first;
1829         struct kvec     *iov;
1830 
1831         status = -EIO;
1832         p = xdr_reserve_space(xdr, 2 * sizeof(*p));
1833         if (!p)
1834                 goto wrap_failed;
1835         opaque_len = p++;
1836         *p = cpu_to_be32(rqstp->rq_seqno);
1837 
1838         if (rpcauth_wrap_req_encode(task, xdr))
1839                 goto wrap_failed;
1840 
1841         status = alloc_enc_pages(rqstp);
1842         if (unlikely(status))
1843                 goto wrap_failed;
1844         first = snd_buf->page_base >> PAGE_SHIFT;
1845         inpages = snd_buf->pages + first;
1846         snd_buf->pages = rqstp->rq_enc_pages;
1847         snd_buf->page_base -= first << PAGE_SHIFT;
1848         /*
1849          * Move the tail into its own page, in case gss_wrap needs
1850          * more space in the head when wrapping.
1851          *
1852          * Still... Why can't gss_wrap just slide the tail down?
1853          */
1854         if (snd_buf->page_len || snd_buf->tail[0].iov_len) {
1855                 char *tmp;
1856 
1857                 tmp = page_address(rqstp->rq_enc_pages[rqstp->rq_enc_pages_num - 1]);
1858                 memcpy(tmp, snd_buf->tail[0].iov_base, snd_buf->tail[0].iov_len);
1859                 snd_buf->tail[0].iov_base = tmp;
1860         }
1861         offset = (u8 *)p - (u8 *)snd_buf->head[0].iov_base;
1862         maj_stat = gss_wrap(ctx->gc_gss_ctx, offset, snd_buf, inpages);
1863         /* slack space should prevent this ever happening: */
1864         if (unlikely(snd_buf->len > snd_buf->buflen))
1865                 goto wrap_failed;
1866         /* We're assuming that when GSS_S_CONTEXT_EXPIRED, the encryption was
1867          * done anyway, so it's safe to put the request on the wire: */
1868         if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1869                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1870         else if (maj_stat)
1871                 goto bad_wrap;
1872 
1873         *opaque_len = cpu_to_be32(snd_buf->len - offset);
1874         /* guess whether the pad goes into the head or the tail: */
1875         if (snd_buf->page_len || snd_buf->tail[0].iov_len)
1876                 iov = snd_buf->tail;
1877         else
1878                 iov = snd_buf->head;
1879         p = iov->iov_base + iov->iov_len;
1880         pad = 3 - ((snd_buf->len - offset - 1) & 3);
1881         memset(p, 0, pad);
1882         iov->iov_len += pad;
1883         snd_buf->len += pad;
1884 
1885         return 0;
1886 wrap_failed:
1887         return status;
1888 bad_wrap:
1889         trace_rpcgss_wrap(task, maj_stat);
1890         return -EIO;
1891 }
1892 
1893 static int gss_wrap_req(struct rpc_task *task, struct xdr_stream *xdr)
1894 {
1895         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
1896         struct gss_cred *gss_cred = container_of(cred, struct gss_cred,
1897                         gc_base);
1898         struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
1899         int status;
1900 
1901         status = -EIO;
1902         if (ctx->gc_proc != RPC_GSS_PROC_DATA) {
1903                 /* The spec seems a little ambiguous here, but I think that not
1904                  * wrapping context destruction requests makes the most sense.
1905                  */
1906                 status = rpcauth_wrap_req_encode(task, xdr);
1907                 goto out;
1908         }
1909         switch (gss_cred->gc_service) {
1910         case RPC_GSS_SVC_NONE:
1911                 status = rpcauth_wrap_req_encode(task, xdr);
1912                 break;
1913         case RPC_GSS_SVC_INTEGRITY:
1914                 status = gss_wrap_req_integ(cred, ctx, task, xdr);
1915                 break;
1916         case RPC_GSS_SVC_PRIVACY:
1917                 status = gss_wrap_req_priv(cred, ctx, task, xdr);
1918                 break;
1919         default:
1920                 status = -EIO;
1921         }
1922 out:
1923         gss_put_ctx(ctx);
1924         return status;
1925 }
1926 
1927 static int
1928 gss_unwrap_resp_auth(struct rpc_cred *cred)
1929 {
1930         struct rpc_auth *auth = cred->cr_auth;
1931 
1932         auth->au_rslack = auth->au_verfsize;
1933         auth->au_ralign = auth->au_verfsize;
1934         return 0;
1935 }
1936 
1937 static int
1938 gss_unwrap_resp_integ(struct rpc_task *task, struct rpc_cred *cred,
1939                       struct gss_cl_ctx *ctx, struct rpc_rqst *rqstp,
1940                       struct xdr_stream *xdr)
1941 {
1942         struct xdr_buf integ_buf, *rcv_buf = &rqstp->rq_rcv_buf;
1943         u32 data_offset, mic_offset, integ_len, maj_stat;
1944         struct rpc_auth *auth = cred->cr_auth;
1945         struct xdr_netobj mic;
1946         __be32 *p;
1947 
1948         p = xdr_inline_decode(xdr, 2 * sizeof(*p));
1949         if (unlikely(!p))
1950                 goto unwrap_failed;
1951         integ_len = be32_to_cpup(p++);
1952         if (integ_len & 3)
1953                 goto unwrap_failed;
1954         data_offset = (u8 *)(p) - (u8 *)rcv_buf->head[0].iov_base;
1955         mic_offset = integ_len + data_offset;
1956         if (mic_offset > rcv_buf->len)
1957                 goto unwrap_failed;
1958         if (be32_to_cpup(p) != rqstp->rq_seqno)
1959                 goto bad_seqno;
1960 
1961         if (xdr_buf_subsegment(rcv_buf, &integ_buf, data_offset, integ_len))
1962                 goto unwrap_failed;
1963         if (xdr_buf_read_netobj(rcv_buf, &mic, mic_offset))
1964                 goto unwrap_failed;
1965         maj_stat = gss_verify_mic(ctx->gc_gss_ctx, &integ_buf, &mic);
1966         if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1967                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1968         if (maj_stat != GSS_S_COMPLETE)
1969                 goto bad_mic;
1970 
1971         auth->au_rslack = auth->au_verfsize + 2 + 1 + XDR_QUADLEN(mic.len);
1972         auth->au_ralign = auth->au_verfsize + 2;
1973         return 0;
1974 unwrap_failed:
1975         trace_rpcgss_unwrap_failed(task);
1976         return -EIO;
1977 bad_seqno:
1978         trace_rpcgss_bad_seqno(task, rqstp->rq_seqno, be32_to_cpup(p));
1979         return -EIO;
1980 bad_mic:
1981         trace_rpcgss_verify_mic(task, maj_stat);
1982         return -EIO;
1983 }
1984 
1985 static int
1986 gss_unwrap_resp_priv(struct rpc_task *task, struct rpc_cred *cred,
1987                      struct gss_cl_ctx *ctx, struct rpc_rqst *rqstp,
1988                      struct xdr_stream *xdr)
1989 {
1990         struct xdr_buf *rcv_buf = &rqstp->rq_rcv_buf;
1991         struct kvec *head = rqstp->rq_rcv_buf.head;
1992         struct rpc_auth *auth = cred->cr_auth;
1993         unsigned int savedlen = rcv_buf->len;
1994         u32 offset, opaque_len, maj_stat;
1995         __be32 *p;
1996 
1997         p = xdr_inline_decode(xdr, 2 * sizeof(*p));
1998         if (unlikely(!p))
1999                 goto unwrap_failed;
2000         opaque_len = be32_to_cpup(p++);
2001         offset = (u8 *)(p) - (u8 *)head->iov_base;
2002         if (offset + opaque_len > rcv_buf->len)
2003                 goto unwrap_failed;
2004         rcv_buf->len = offset + opaque_len;
2005 
2006         maj_stat = gss_unwrap(ctx->gc_gss_ctx, offset, rcv_buf);
2007         if (maj_stat == GSS_S_CONTEXT_EXPIRED)
2008                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
2009         if (maj_stat != GSS_S_COMPLETE)
2010                 goto bad_unwrap;
2011         /* gss_unwrap decrypted the sequence number */
2012         if (be32_to_cpup(p++) != rqstp->rq_seqno)
2013                 goto bad_seqno;
2014 
2015         /* gss_unwrap redacts the opaque blob from the head iovec.
2016          * rcv_buf has changed, thus the stream needs to be reset.
2017          */
2018         xdr_init_decode(xdr, rcv_buf, p, rqstp);
2019 
2020         auth->au_rslack = auth->au_verfsize + 2 +
2021                           XDR_QUADLEN(savedlen - rcv_buf->len);
2022         auth->au_ralign = auth->au_verfsize + 2 +
2023                           XDR_QUADLEN(savedlen - rcv_buf->len);
2024         return 0;
2025 unwrap_failed:
2026         trace_rpcgss_unwrap_failed(task);
2027         return -EIO;
2028 bad_seqno:
2029         trace_rpcgss_bad_seqno(task, rqstp->rq_seqno, be32_to_cpup(--p));
2030         return -EIO;
2031 bad_unwrap:
2032         trace_rpcgss_unwrap(task, maj_stat);
2033         return -EIO;
2034 }
2035 
2036 static bool
2037 gss_seq_is_newer(u32 new, u32 old)
2038 {
2039         return (s32)(new - old) > 0;
2040 }
2041 
2042 static bool
2043 gss_xmit_need_reencode(struct rpc_task *task)
2044 {
2045         struct rpc_rqst *req = task->tk_rqstp;
2046         struct rpc_cred *cred = req->rq_cred;
2047         struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
2048         u32 win, seq_xmit = 0;
2049         bool ret = true;
2050 
2051         if (!ctx)
2052                 goto out;
2053 
2054         if (gss_seq_is_newer(req->rq_seqno, READ_ONCE(ctx->gc_seq)))
2055                 goto out_ctx;
2056 
2057         seq_xmit = READ_ONCE(ctx->gc_seq_xmit);
2058         while (gss_seq_is_newer(req->rq_seqno, seq_xmit)) {
2059                 u32 tmp = seq_xmit;
2060 
2061                 seq_xmit = cmpxchg(&ctx->gc_seq_xmit, tmp, req->rq_seqno);
2062                 if (seq_xmit == tmp) {
2063                         ret = false;
2064                         goto out_ctx;
2065                 }
2066         }
2067 
2068         win = ctx->gc_win;
2069         if (win > 0)
2070                 ret = !gss_seq_is_newer(req->rq_seqno, seq_xmit - win);
2071 
2072 out_ctx:
2073         gss_put_ctx(ctx);
2074 out:
2075         trace_rpcgss_need_reencode(task, seq_xmit, ret);
2076         return ret;
2077 }
2078 
2079 static int
2080 gss_unwrap_resp(struct rpc_task *task, struct xdr_stream *xdr)
2081 {
2082         struct rpc_rqst *rqstp = task->tk_rqstp;
2083         struct rpc_cred *cred = rqstp->rq_cred;
2084         struct gss_cred *gss_cred = container_of(cred, struct gss_cred,
2085                         gc_base);
2086         struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
2087         int status = -EIO;
2088 
2089         if (ctx->gc_proc != RPC_GSS_PROC_DATA)
2090                 goto out_decode;
2091         switch (gss_cred->gc_service) {
2092         case RPC_GSS_SVC_NONE:
2093                 status = gss_unwrap_resp_auth(cred);
2094                 break;
2095         case RPC_GSS_SVC_INTEGRITY:
2096                 status = gss_unwrap_resp_integ(task, cred, ctx, rqstp, xdr);
2097                 break;
2098         case RPC_GSS_SVC_PRIVACY:
2099                 status = gss_unwrap_resp_priv(task, cred, ctx, rqstp, xdr);
2100                 break;
2101         }
2102         if (status)
2103                 goto out;
2104 
2105 out_decode:
2106         status = rpcauth_unwrap_resp_decode(task, xdr);
2107 out:
2108         gss_put_ctx(ctx);
2109         return status;
2110 }
2111 
2112 static const struct rpc_authops authgss_ops = {
2113         .owner          = THIS_MODULE,
2114         .au_flavor      = RPC_AUTH_GSS,
2115         .au_name        = "RPCSEC_GSS",
2116         .create         = gss_create,
2117         .destroy        = gss_destroy,
2118         .hash_cred      = gss_hash_cred,
2119         .lookup_cred    = gss_lookup_cred,
2120         .crcreate       = gss_create_cred,
2121         .list_pseudoflavors = gss_mech_list_pseudoflavors,
2122         .info2flavor    = gss_mech_info2flavor,
2123         .flavor2info    = gss_mech_flavor2info,
2124 };
2125 
2126 static const struct rpc_credops gss_credops = {
2127         .cr_name                = "AUTH_GSS",
2128         .crdestroy              = gss_destroy_cred,
2129         .cr_init                = gss_cred_init,
2130         .crmatch                = gss_match,
2131         .crmarshal              = gss_marshal,
2132         .crrefresh              = gss_refresh,
2133         .crvalidate             = gss_validate,
2134         .crwrap_req             = gss_wrap_req,
2135         .crunwrap_resp          = gss_unwrap_resp,
2136         .crkey_timeout          = gss_key_timeout,
2137         .crstringify_acceptor   = gss_stringify_acceptor,
2138         .crneed_reencode        = gss_xmit_need_reencode,
2139 };
2140 
2141 static const struct rpc_credops gss_nullops = {
2142         .cr_name                = "AUTH_GSS",
2143         .crdestroy              = gss_destroy_nullcred,
2144         .crmatch                = gss_match,
2145         .crmarshal              = gss_marshal,
2146         .crrefresh              = gss_refresh_null,
2147         .crvalidate             = gss_validate,
2148         .crwrap_req             = gss_wrap_req,
2149         .crunwrap_resp          = gss_unwrap_resp,
2150         .crstringify_acceptor   = gss_stringify_acceptor,
2151 };
2152 
2153 static const struct rpc_pipe_ops gss_upcall_ops_v0 = {
2154         .upcall         = gss_v0_upcall,
2155         .downcall       = gss_pipe_downcall,
2156         .destroy_msg    = gss_pipe_destroy_msg,
2157         .open_pipe      = gss_pipe_open_v0,
2158         .release_pipe   = gss_pipe_release,
2159 };
2160 
2161 static const struct rpc_pipe_ops gss_upcall_ops_v1 = {
2162         .upcall         = gss_v1_upcall,
2163         .downcall       = gss_pipe_downcall,
2164         .destroy_msg    = gss_pipe_destroy_msg,
2165         .open_pipe      = gss_pipe_open_v1,
2166         .release_pipe   = gss_pipe_release,
2167 };
2168 
2169 static __net_init int rpcsec_gss_init_net(struct net *net)
2170 {
2171         return gss_svc_init_net(net);
2172 }
2173 
2174 static __net_exit void rpcsec_gss_exit_net(struct net *net)
2175 {
2176         gss_svc_shutdown_net(net);
2177 }
2178 
2179 static struct pernet_operations rpcsec_gss_net_ops = {
2180         .init = rpcsec_gss_init_net,
2181         .exit = rpcsec_gss_exit_net,
2182 };
2183 
2184 /*
2185  * Initialize RPCSEC_GSS module
2186  */
2187 static int __init init_rpcsec_gss(void)
2188 {
2189         int err = 0;
2190 
2191         err = rpcauth_register(&authgss_ops);
2192         if (err)
2193                 goto out;
2194         err = gss_svc_init();
2195         if (err)
2196                 goto out_unregister;
2197         err = register_pernet_subsys(&rpcsec_gss_net_ops);
2198         if (err)
2199                 goto out_svc_exit;
2200         rpc_init_wait_queue(&pipe_version_rpc_waitqueue, "gss pipe version");
2201         return 0;
2202 out_svc_exit:
2203         gss_svc_shutdown();
2204 out_unregister:
2205         rpcauth_unregister(&authgss_ops);
2206 out:
2207         return err;
2208 }
2209 
2210 static void __exit exit_rpcsec_gss(void)
2211 {
2212         unregister_pernet_subsys(&rpcsec_gss_net_ops);
2213         gss_svc_shutdown();
2214         rpcauth_unregister(&authgss_ops);
2215         rcu_barrier(); /* Wait for completion of call_rcu()'s */
2216 }
2217 
2218 MODULE_ALIAS("rpc-auth-6");
2219 MODULE_LICENSE("GPL");
2220 module_param_named(expired_cred_retry_delay,
2221                    gss_expired_cred_retry_delay,
2222                    uint, 0644);
2223 MODULE_PARM_DESC(expired_cred_retry_delay, "Timeout (in seconds) until "
2224                 "the RPC engine retries an expired credential");
2225 
2226 module_param_named(key_expire_timeo,
2227                    gss_key_expire_timeo,
2228                    uint, 0644);
2229 MODULE_PARM_DESC(key_expire_timeo, "Time (in seconds) at the end of a "
2230                 "credential keys lifetime where the NFS layer cleans up "
2231                 "prior to key expiration");
2232 
2233 module_init(init_rpcsec_gss)
2234 module_exit(exit_rpcsec_gss)
2235 

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