net/sunrpc/auth_gss/auth_gss.c

   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/gss_krb5.h>
  24 #include <linux/sunrpc/svcauth_gss.h>
  25 #include <linux/sunrpc/gss_err.h>
  26 #include <linux/workqueue.h>
  27 #include <linux/sunrpc/rpc_pipe_fs.h>
  28 #include <linux/sunrpc/gss_api.h>
  29 #include <linux/uaccess.h>
  30 #include <linux/hashtable.h>
  31
  32 #include "../netns.h"
  33
  34 #include <trace/events/rpcgss.h>
  35
  36 static const struct rpc_authops authgss_ops;
  37
  38 static const struct rpc_credops gss_credops;
  39 static const struct rpc_credops gss_nullops;
  40
  41 #define GSS_RETRY_EXPIRED 5
  42 static unsigned int gss_expired_cred_retry_delay = GSS_RETRY_EXPIRED;
  43
  44 #define GSS_KEY_EXPIRE_TIMEO 240
  45 static unsigned int gss_key_expire_timeo = GSS_KEY_EXPIRE_TIMEO;
  46
  47 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
  48 # define RPCDBG_FACILITY        RPCDBG_AUTH
  49 #endif
  50
  51 #define GSS_CRED_SLACK          (RPC_MAX_AUTH_SIZE * 2)
  52 /* length of a krb5 verifier (48), plus data added before arguments when
  53  * using integrity (two 4-byte integers): */
  54 #define GSS_VERF_SLACK          100
  55
  56 static DEFINE_HASHTABLE(gss_auth_hash_table, 4);
  57 static DEFINE_SPINLOCK(gss_auth_hash_lock);
  58
  59 struct gss_pipe {
  60         struct rpc_pipe_dir_object pdo;
  61         struct rpc_pipe *pipe;
  62         struct rpc_clnt *clnt;
  63         const char *name;
  64         struct kref kref;
  65 };
  66
  67 struct gss_auth {
  68         struct kref kref;
  69         struct hlist_node hash;
  70         struct rpc_auth rpc_auth;
  71         struct gss_api_mech *mech;
  72         enum rpc_gss_svc service;
  73         struct rpc_clnt *client;
  74         struct net *net;
  75         /*
  76          * There are two upcall pipes; dentry[1], named "gssd", is used
  77          * for the new text-based upcall; dentry[0] is named after the
  78          * mechanism (for example, "krb5") and exists for
  79          * backwards-compatibility with older gssd's.
  80          */
  81         struct gss_pipe *gss_pipe[2];
  82         const char *target_name;
  83 };
  84
  85 /* pipe_version >= 0 if and only if someone has a pipe open. */
  86 static DEFINE_SPINLOCK(pipe_version_lock);
  87 static struct rpc_wait_queue pipe_version_rpc_waitqueue;
  88 static DECLARE_WAIT_QUEUE_HEAD(pipe_version_waitqueue);
  89 static void gss_put_auth(struct gss_auth *gss_auth);
  90
  91 static void gss_free_ctx(struct gss_cl_ctx *);
  92 static const struct rpc_pipe_ops gss_upcall_ops_v0;
  93 static const struct rpc_pipe_ops gss_upcall_ops_v1;
  94
  95 static inline struct gss_cl_ctx *
  96 gss_get_ctx(struct gss_cl_ctx *ctx)
  97 {
  98         refcount_inc(&ctx->count);
  99         return ctx;
 100 }
 101
 102 static inline void
 103 gss_put_ctx(struct gss_cl_ctx *ctx)
 104 {
 105         if (refcount_dec_and_test(&ctx->count))
 106                 gss_free_ctx(ctx);
 107 }
 108
 109 /* gss_cred_set_ctx:
 110  * called by gss_upcall_callback and gss_create_upcall in order
 111  * to set the gss context. The actual exchange of an old context
 112  * and a new one is protected by the pipe->lock.
 113  */
 114 static void
 115 gss_cred_set_ctx(struct rpc_cred *cred, struct gss_cl_ctx *ctx)
 116 {
 117         struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
 118
 119         if (!test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags))
 120                 return;
 121         gss_get_ctx(ctx);
 122         rcu_assign_pointer(gss_cred->gc_ctx, ctx);
 123         set_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
 124         smp_mb__before_atomic();
 125         clear_bit(RPCAUTH_CRED_NEW, &cred->cr_flags);
 126 }
 127
 128 static const void *
 129 simple_get_bytes(const void *p, const void *end, void *res, size_t len)
 130 {
 131         const void *q = (const void *)((const char *)p + len);
 132         if (unlikely(q > end || q < p))
 133                 return ERR_PTR(-EFAULT);
 134         memcpy(res, p, len);
 135         return q;
 136 }
 137
 138 static inline const void *
 139 simple_get_netobj(const void *p, const void *end, struct xdr_netobj *dest)
 140 {
 141         const void *q;
 142         unsigned int len;
 143
 144         p = simple_get_bytes(p, end, &len, sizeof(len));
 145         if (IS_ERR(p))
 146                 return p;
 147         q = (const void *)((const char *)p + len);
 148         if (unlikely(q > end || q < p))
 149                 return ERR_PTR(-EFAULT);
 150         dest->data = kmemdup(p, len, GFP_NOFS);
 151         if (unlikely(dest->data == NULL))
 152                 return ERR_PTR(-ENOMEM);
 153         dest->len = len;
 154         return q;
 155 }
 156
 157 static struct gss_cl_ctx *
 158 gss_cred_get_ctx(struct rpc_cred *cred)
 159 {
 160         struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
 161         struct gss_cl_ctx *ctx = NULL;
 162
 163         rcu_read_lock();
 164         ctx = rcu_dereference(gss_cred->gc_ctx);
 165         if (ctx)
 166                 gss_get_ctx(ctx);
 167         rcu_read_unlock();
 168         return ctx;
 169 }
 170
 171 static struct gss_cl_ctx *
 172 gss_alloc_context(void)
 173 {
 174         struct gss_cl_ctx *ctx;
 175
 176         ctx = kzalloc(sizeof(*ctx), GFP_NOFS);
 177         if (ctx != NULL) {
 178                 ctx->gc_proc = RPC_GSS_PROC_DATA;
 179                 ctx->gc_seq = 1;        /* NetApp 6.4R1 doesn't accept seq. no. 0 */
 180                 spin_lock_init(&ctx->gc_seq_lock);
 181                 refcount_set(&ctx->count,1);
 182         }
 183         return ctx;
 184 }
 185
 186 #define GSSD_MIN_TIMEOUT (60 * 60)
 187 static const void *
 188 gss_fill_context(const void *p, const void *end, struct gss_cl_ctx *ctx, struct gss_api_mech *gm)
 189 {
 190         const void *q;
 191         unsigned int seclen;
 192         unsigned int timeout;
 193         unsigned long now = jiffies;
 194         u32 window_size;
 195         int ret;
 196
 197         /* First unsigned int gives the remaining lifetime in seconds of the
 198          * credential - e.g. the remaining TGT lifetime for Kerberos or
 199          * the -t value passed to GSSD.
 200          */
 201         p = simple_get_bytes(p, end, &timeout, sizeof(timeout));
 202         if (IS_ERR(p))
 203                 goto err;
 204         if (timeout == 0)
 205                 timeout = GSSD_MIN_TIMEOUT;
 206         ctx->gc_expiry = now + ((unsigned long)timeout * HZ);
 207         /* Sequence number window. Determines the maximum number of
 208          * simultaneous requests
 209          */
 210         p = simple_get_bytes(p, end, &window_size, sizeof(window_size));
 211         if (IS_ERR(p))
 212                 goto err;
 213         ctx->gc_win = window_size;
 214         /* gssd signals an error by passing ctx->gc_win = 0: */
 215         if (ctx->gc_win == 0) {
 216                 /*
 217                  * in which case, p points to an error code. Anything other
 218                  * than -EKEYEXPIRED gets converted to -EACCES.
 219                  */
 220                 p = simple_get_bytes(p, end, &ret, sizeof(ret));
 221                 if (!IS_ERR(p))
 222                         p = (ret == -EKEYEXPIRED) ? ERR_PTR(-EKEYEXPIRED) :
 223                                                     ERR_PTR(-EACCES);
 224                 goto err;
 225         }
 226         /* copy the opaque wire context */
 227         p = simple_get_netobj(p, end, &ctx->gc_wire_ctx);
 228         if (IS_ERR(p))
 229                 goto err;
 230         /* import the opaque security context */
 231         p  = simple_get_bytes(p, end, &seclen, sizeof(seclen));
 232         if (IS_ERR(p))
 233                 goto err;
 234         q = (const void *)((const char *)p + seclen);
 235         if (unlikely(q > end || q < p)) {
 236                 p = ERR_PTR(-EFAULT);
 237                 goto err;
 238         }
 239         ret = gss_import_sec_context(p, seclen, gm, &ctx->gc_gss_ctx, NULL, GFP_NOFS);
 240         if (ret < 0) {
 241                 trace_rpcgss_import_ctx(ret);
 242                 p = ERR_PTR(ret);
 243                 goto err;
 244         }
 245
 246         /* is there any trailing data? */
 247         if (q == end) {
 248                 p = q;
 249                 goto done;
 250         }
 251
 252         /* pull in acceptor name (if there is one) */
 253         p = simple_get_netobj(q, end, &ctx->gc_acceptor);
 254         if (IS_ERR(p))
 255                 goto err;
 256 done:
 257         trace_rpcgss_context(ctx->gc_expiry, now, timeout,
 258                              ctx->gc_acceptor.len, ctx->gc_acceptor.data);
 259 err:
 260         return p;
 261 }
 262
 263 /* XXX: Need some documentation about why UPCALL_BUF_LEN is so small.
 264  *      Is user space expecting no more than UPCALL_BUF_LEN bytes?
 265  *      Note that there are now _two_ NI_MAXHOST sized data items
 266  *      being passed in this string.
 267  */
 268 #define UPCALL_BUF_LEN  256
 269
 270 struct gss_upcall_msg {
 271         refcount_t count;
 272         kuid_t  uid;
 273         const char *service_name;
 274         struct rpc_pipe_msg msg;
 275         struct list_head list;
 276         struct gss_auth *auth;
 277         struct rpc_pipe *pipe;
 278         struct rpc_wait_queue rpc_waitqueue;
 279         wait_queue_head_t waitqueue;
 280         struct gss_cl_ctx *ctx;
 281         char databuf[UPCALL_BUF_LEN];
 282 };
 283
 284 static int get_pipe_version(struct net *net)
 285 {
 286         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 287         int ret;
 288
 289         spin_lock(&pipe_version_lock);
 290         if (sn->pipe_version >= 0) {
 291                 atomic_inc(&sn->pipe_users);
 292                 ret = sn->pipe_version;
 293         } else
 294                 ret = -EAGAIN;
 295         spin_unlock(&pipe_version_lock);
 296         return ret;
 297 }
 298
 299 static void put_pipe_version(struct net *net)
 300 {
 301         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 302
 303         if (atomic_dec_and_lock(&sn->pipe_users, &pipe_version_lock)) {
 304                 sn->pipe_version = -1;
 305                 spin_unlock(&pipe_version_lock);
 306         }
 307 }
 308
 309 static void
 310 gss_release_msg(struct gss_upcall_msg *gss_msg)
 311 {
 312         struct net *net = gss_msg->auth->net;
 313         if (!refcount_dec_and_test(&gss_msg->count))
 314                 return;
 315         put_pipe_version(net);
 316         BUG_ON(!list_empty(&gss_msg->list));
 317         if (gss_msg->ctx != NULL)
 318                 gss_put_ctx(gss_msg->ctx);
 319         rpc_destroy_wait_queue(&gss_msg->rpc_waitqueue);
 320         gss_put_auth(gss_msg->auth);
 321         kfree_const(gss_msg->service_name);
 322         kfree(gss_msg);
 323 }
 324
 325 static struct gss_upcall_msg *
 326 __gss_find_upcall(struct rpc_pipe *pipe, kuid_t uid, const struct gss_auth *auth)
 327 {
 328         struct gss_upcall_msg *pos;
 329         list_for_each_entry(pos, &pipe->in_downcall, list) {
 330                 if (!uid_eq(pos->uid, uid))
 331                         continue;
 332                 if (auth && pos->auth->service != auth->service)
 333                         continue;
 334                 refcount_inc(&pos->count);
 335                 return pos;
 336         }
 337         return NULL;
 338 }
 339
 340 /* Try to add an upcall to the pipefs queue.
 341  * If an upcall owned by our uid already exists, then we return a reference
 342  * to that upcall instead of adding the new upcall.
 343  */
 344 static inline struct gss_upcall_msg *
 345 gss_add_msg(struct gss_upcall_msg *gss_msg)
 346 {
 347         struct rpc_pipe *pipe = gss_msg->pipe;
 348         struct gss_upcall_msg *old;
 349
 350         spin_lock(&pipe->lock);
 351         old = __gss_find_upcall(pipe, gss_msg->uid, gss_msg->auth);
 352         if (old == NULL) {
 353                 refcount_inc(&gss_msg->count);
 354                 list_add(&gss_msg->list, &pipe->in_downcall);
 355         } else
 356                 gss_msg = old;
 357         spin_unlock(&pipe->lock);
 358         return gss_msg;
 359 }
 360
 361 static void
 362 __gss_unhash_msg(struct gss_upcall_msg *gss_msg)
 363 {
 364         list_del_init(&gss_msg->list);
 365         rpc_wake_up_status(&gss_msg->rpc_waitqueue, gss_msg->msg.errno);
 366         wake_up_all(&gss_msg->waitqueue);
 367         refcount_dec(&gss_msg->count);
 368 }
 369
 370 static void
 371 gss_unhash_msg(struct gss_upcall_msg *gss_msg)
 372 {
 373         struct rpc_pipe *pipe = gss_msg->pipe;
 374
 375         if (list_empty(&gss_msg->list))
 376                 return;
 377         spin_lock(&pipe->lock);
 378         if (!list_empty(&gss_msg->list))
 379                 __gss_unhash_msg(gss_msg);
 380         spin_unlock(&pipe->lock);
 381 }
 382
 383 static void
 384 gss_handle_downcall_result(struct gss_cred *gss_cred, struct gss_upcall_msg *gss_msg)
 385 {
 386         switch (gss_msg->msg.errno) {
 387         case 0:
 388                 if (gss_msg->ctx == NULL)
 389                         break;
 390                 clear_bit(RPCAUTH_CRED_NEGATIVE, &gss_cred->gc_base.cr_flags);
 391                 gss_cred_set_ctx(&gss_cred->gc_base, gss_msg->ctx);
 392                 break;
 393         case -EKEYEXPIRED:
 394                 set_bit(RPCAUTH_CRED_NEGATIVE, &gss_cred->gc_base.cr_flags);
 395         }
 396         gss_cred->gc_upcall_timestamp = jiffies;
 397         gss_cred->gc_upcall = NULL;
 398         rpc_wake_up_status(&gss_msg->rpc_waitqueue, gss_msg->msg.errno);
 399 }
 400
 401 static void
 402 gss_upcall_callback(struct rpc_task *task)
 403 {
 404         struct gss_cred *gss_cred = container_of(task->tk_rqstp->rq_cred,
 405                         struct gss_cred, gc_base);
 406         struct gss_upcall_msg *gss_msg = gss_cred->gc_upcall;
 407         struct rpc_pipe *pipe = gss_msg->pipe;
 408
 409         spin_lock(&pipe->lock);
 410         gss_handle_downcall_result(gss_cred, gss_msg);
 411         spin_unlock(&pipe->lock);
 412         task->tk_status = gss_msg->msg.errno;
 413         gss_release_msg(gss_msg);
 414 }
 415
 416 static void gss_encode_v0_msg(struct gss_upcall_msg *gss_msg,
 417                               const struct cred *cred)
 418 {
 419         struct user_namespace *userns = cred->user_ns;
 420
 421         uid_t uid = from_kuid_munged(userns, gss_msg->uid);
 422         memcpy(gss_msg->databuf, &uid, sizeof(uid));
 423         gss_msg->msg.data = gss_msg->databuf;
 424         gss_msg->msg.len = sizeof(uid);
 425
 426         BUILD_BUG_ON(sizeof(uid) > sizeof(gss_msg->databuf));
 427 }
 428
 429 static ssize_t
 430 gss_v0_upcall(struct file *file, struct rpc_pipe_msg *msg,
 431                 char __user *buf, size_t buflen)
 432 {
 433         struct gss_upcall_msg *gss_msg = container_of(msg,
 434                                                       struct gss_upcall_msg,
 435                                                       msg);
 436         if (msg->copied == 0)
 437                 gss_encode_v0_msg(gss_msg, file->f_cred);
 438         return rpc_pipe_generic_upcall(file, msg, buf, buflen);
 439 }
 440
 441 static int gss_encode_v1_msg(struct gss_upcall_msg *gss_msg,
 442                                 const char *service_name,
 443                                 const char *target_name,
 444                                 const struct cred *cred)
 445 {
 446         struct user_namespace *userns = cred->user_ns;
 447         struct gss_api_mech *mech = gss_msg->auth->mech;
 448         char *p = gss_msg->databuf;
 449         size_t buflen = sizeof(gss_msg->databuf);
 450         int len;
 451
 452         len = scnprintf(p, buflen, "mech=%s uid=%d", mech->gm_name,
 453                         from_kuid_munged(userns, gss_msg->uid));
 454         buflen -= len;
 455         p += len;
 456         gss_msg->msg.len = len;
 457
 458         /*
 459          * target= is a full service principal that names the remote
 460          * identity that we are authenticating to.
 461          */
 462         if (target_name) {
 463                 len = scnprintf(p, buflen, " target=%s", target_name);
 464                 buflen -= len;
 465                 p += len;
 466                 gss_msg->msg.len += len;
 467         }
 468
 469         /*
 470          * gssd uses service= and srchost= to select a matching key from
 471          * the system's keytab to use as the source principal.
 472          *
 473          * service= is the service name part of the source principal,
 474          * or "*" (meaning choose any).
 475          *
 476          * srchost= is the hostname part of the source principal. When
 477          * not provided, gssd uses the local hostname.
 478          */
 479         if (service_name) {
 480                 char *c = strchr(service_name, '@');
 481
 482                 if (!c)
 483                         len = scnprintf(p, buflen, " service=%s",
 484                                         service_name);
 485                 else
 486                         len = scnprintf(p, buflen,
 487                                         " service=%.*s srchost=%s",
 488                                         (int)(c - service_name),
 489                                         service_name, c + 1);
 490                 buflen -= len;
 491                 p += len;
 492                 gss_msg->msg.len += len;
 493         }
 494
 495         if (mech->gm_upcall_enctypes) {
 496                 len = scnprintf(p, buflen, " enctypes=%s",
 497                                 mech->gm_upcall_enctypes);
 498                 buflen -= len;
 499                 p += len;
 500                 gss_msg->msg.len += len;
 501         }
 502         trace_rpcgss_upcall_msg(gss_msg->databuf);
 503         len = scnprintf(p, buflen, "\n");
 504         if (len == 0)
 505                 goto out_overflow;
 506         gss_msg->msg.len += len;
 507         gss_msg->msg.data = gss_msg->databuf;
 508         return 0;
 509 out_overflow:
 510         WARN_ON_ONCE(1);
 511         return -ENOMEM;
 512 }
 513
 514 static ssize_t
 515 gss_v1_upcall(struct file *file, struct rpc_pipe_msg *msg,
 516                 char __user *buf, size_t buflen)
 517 {
 518         struct gss_upcall_msg *gss_msg = container_of(msg,
 519                                                       struct gss_upcall_msg,
 520                                                       msg);
 521         int err;
 522         if (msg->copied == 0) {
 523                 err = gss_encode_v1_msg(gss_msg,
 524                                         gss_msg->service_name,
 525                                         gss_msg->auth->target_name,
 526                                         file->f_cred);
 527                 if (err)
 528                         return err;
 529         }
 530         return rpc_pipe_generic_upcall(file, msg, buf, buflen);
 531 }
 532
 533 static struct gss_upcall_msg *
 534 gss_alloc_msg(struct gss_auth *gss_auth,
 535                 kuid_t uid, const char *service_name)
 536 {
 537         struct gss_upcall_msg *gss_msg;
 538         int vers;
 539         int err = -ENOMEM;
 540
 541         gss_msg = kzalloc(sizeof(*gss_msg), GFP_NOFS);
 542         if (gss_msg == NULL)
 543                 goto err;
 544         vers = get_pipe_version(gss_auth->net);
 545         err = vers;
 546         if (err < 0)
 547                 goto err_free_msg;
 548         gss_msg->pipe = gss_auth->gss_pipe[vers]->pipe;
 549         INIT_LIST_HEAD(&gss_msg->list);
 550         rpc_init_wait_queue(&gss_msg->rpc_waitqueue, "RPCSEC_GSS upcall waitq");
 551         init_waitqueue_head(&gss_msg->waitqueue);
 552         refcount_set(&gss_msg->count, 1);
 553         gss_msg->uid = uid;
 554         gss_msg->auth = gss_auth;
 555         kref_get(&gss_auth->kref);
 556         if (service_name) {
 557                 gss_msg->service_name = kstrdup_const(service_name, GFP_NOFS);
 558                 if (!gss_msg->service_name) {
 559                         err = -ENOMEM;
 560                         goto err_put_pipe_version;
 561                 }
 562         }
 563         return gss_msg;
 564 err_put_pipe_version:
 565         put_pipe_version(gss_auth->net);
 566 err_free_msg:
 567         kfree(gss_msg);
 568 err:
 569         return ERR_PTR(err);
 570 }
 571
 572 static struct gss_upcall_msg *
 573 gss_setup_upcall(struct gss_auth *gss_auth, struct rpc_cred *cred)
 574 {
 575         struct gss_cred *gss_cred = container_of(cred,
 576                         struct gss_cred, gc_base);
 577         struct gss_upcall_msg *gss_new, *gss_msg;
 578         kuid_t uid = cred->cr_cred->fsuid;
 579
 580         gss_new = gss_alloc_msg(gss_auth, uid, gss_cred->gc_principal);
 581         if (IS_ERR(gss_new))
 582                 return gss_new;
 583         gss_msg = gss_add_msg(gss_new);
 584         if (gss_msg == gss_new) {
 585                 int res;
 586                 refcount_inc(&gss_msg->count);
 587                 res = rpc_queue_upcall(gss_new->pipe, &gss_new->msg);
 588                 if (res) {
 589                         gss_unhash_msg(gss_new);
 590                         refcount_dec(&gss_msg->count);
 591                         gss_release_msg(gss_new);
 592                         gss_msg = ERR_PTR(res);
 593                 }
 594         } else
 595                 gss_release_msg(gss_new);
 596         return gss_msg;
 597 }
 598
 599 static void warn_gssd(void)
 600 {
 601         dprintk("AUTH_GSS upcall failed. Please check user daemon is running.\n");
 602 }
 603
 604 static inline int
 605 gss_refresh_upcall(struct rpc_task *task)
 606 {
 607         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 608         struct gss_auth *gss_auth = container_of(cred->cr_auth,
 609                         struct gss_auth, rpc_auth);
 610         struct gss_cred *gss_cred = container_of(cred,
 611                         struct gss_cred, gc_base);
 612         struct gss_upcall_msg *gss_msg;
 613         struct rpc_pipe *pipe;
 614         int err = 0;
 615
 616         gss_msg = gss_setup_upcall(gss_auth, cred);
 617         if (PTR_ERR(gss_msg) == -EAGAIN) {
 618                 /* XXX: warning on the first, under the assumption we
 619                  * shouldn't normally hit this case on a refresh. */
 620                 warn_gssd();
 621                 rpc_sleep_on_timeout(&pipe_version_rpc_waitqueue,
 622                                 task, NULL, jiffies + (15 * HZ));
 623                 err = -EAGAIN;
 624                 goto out;
 625         }
 626         if (IS_ERR(gss_msg)) {
 627                 err = PTR_ERR(gss_msg);
 628                 goto out;
 629         }
 630         pipe = gss_msg->pipe;
 631         spin_lock(&pipe->lock);
 632         if (gss_cred->gc_upcall != NULL)
 633                 rpc_sleep_on(&gss_cred->gc_upcall->rpc_waitqueue, task, NULL);
 634         else if (gss_msg->ctx == NULL && gss_msg->msg.errno >= 0) {
 635                 gss_cred->gc_upcall = gss_msg;
 636                 /* gss_upcall_callback will release the reference to gss_upcall_msg */
 637                 refcount_inc(&gss_msg->count);
 638                 rpc_sleep_on(&gss_msg->rpc_waitqueue, task, gss_upcall_callback);
 639         } else {
 640                 gss_handle_downcall_result(gss_cred, gss_msg);
 641                 err = gss_msg->msg.errno;
 642         }
 643         spin_unlock(&pipe->lock);
 644         gss_release_msg(gss_msg);
 645 out:
 646         trace_rpcgss_upcall_result(from_kuid(&init_user_ns,
 647                                              cred->cr_cred->fsuid), err);
 648         return err;
 649 }
 650
 651 static inline int
 652 gss_create_upcall(struct gss_auth *gss_auth, struct gss_cred *gss_cred)
 653 {
 654         struct net *net = gss_auth->net;
 655         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 656         struct rpc_pipe *pipe;
 657         struct rpc_cred *cred = &gss_cred->gc_base;
 658         struct gss_upcall_msg *gss_msg;
 659         DEFINE_WAIT(wait);
 660         int err;
 661
 662 retry:
 663         err = 0;
 664         /* if gssd is down, just skip upcalling altogether */
 665         if (!gssd_running(net)) {
 666                 warn_gssd();
 667                 err = -EACCES;
 668                 goto out;
 669         }
 670         gss_msg = gss_setup_upcall(gss_auth, cred);
 671         if (PTR_ERR(gss_msg) == -EAGAIN) {
 672                 err = wait_event_interruptible_timeout(pipe_version_waitqueue,
 673                                 sn->pipe_version >= 0, 15 * HZ);
 674                 if (sn->pipe_version < 0) {
 675                         warn_gssd();
 676                         err = -EACCES;
 677                 }
 678                 if (err < 0)
 679                         goto out;
 680                 goto retry;
 681         }
 682         if (IS_ERR(gss_msg)) {
 683                 err = PTR_ERR(gss_msg);
 684                 goto out;
 685         }
 686         pipe = gss_msg->pipe;
 687         for (;;) {
 688                 prepare_to_wait(&gss_msg->waitqueue, &wait, TASK_KILLABLE);
 689                 spin_lock(&pipe->lock);
 690                 if (gss_msg->ctx != NULL || gss_msg->msg.errno < 0) {
 691                         break;
 692                 }
 693                 spin_unlock(&pipe->lock);
 694                 if (fatal_signal_pending(current)) {
 695                         err = -ERESTARTSYS;
 696                         goto out_intr;
 697                 }
 698                 schedule();
 699         }
 700         if (gss_msg->ctx)
 701                 gss_cred_set_ctx(cred, gss_msg->ctx);
 702         else
 703                 err = gss_msg->msg.errno;
 704         spin_unlock(&pipe->lock);
 705 out_intr:
 706         finish_wait(&gss_msg->waitqueue, &wait);
 707         gss_release_msg(gss_msg);
 708 out:
 709         trace_rpcgss_upcall_result(from_kuid(&init_user_ns,
 710                                              cred->cr_cred->fsuid), err);
 711         return err;
 712 }
 713
 714 #define MSG_BUF_MAXSIZE 1024
 715
 716 static ssize_t
 717 gss_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 718 {
 719         const void *p, *end;
 720         void *buf;
 721         struct gss_upcall_msg *gss_msg;
 722         struct rpc_pipe *pipe = RPC_I(file_inode(filp))->pipe;
 723         struct gss_cl_ctx *ctx;
 724         uid_t id;
 725         kuid_t uid;
 726         ssize_t err = -EFBIG;
 727
 728         if (mlen > MSG_BUF_MAXSIZE)
 729                 goto out;
 730         err = -ENOMEM;
 731         buf = kmalloc(mlen, GFP_NOFS);
 732         if (!buf)
 733                 goto out;
 734
 735         err = -EFAULT;
 736         if (copy_from_user(buf, src, mlen))
 737                 goto err;
 738
 739         end = (const void *)((char *)buf + mlen);
 740         p = simple_get_bytes(buf, end, &id, sizeof(id));
 741         if (IS_ERR(p)) {
 742                 err = PTR_ERR(p);
 743                 goto err;
 744         }
 745
 746         uid = make_kuid(current_user_ns(), id);
 747         if (!uid_valid(uid)) {
 748                 err = -EINVAL;
 749                 goto err;
 750         }
 751
 752         err = -ENOMEM;
 753         ctx = gss_alloc_context();
 754         if (ctx == NULL)
 755                 goto err;
 756
 757         err = -ENOENT;
 758         /* Find a matching upcall */
 759         spin_lock(&pipe->lock);
 760         gss_msg = __gss_find_upcall(pipe, uid, NULL);
 761         if (gss_msg == NULL) {
 762                 spin_unlock(&pipe->lock);
 763                 goto err_put_ctx;
 764         }
 765         list_del_init(&gss_msg->list);
 766         spin_unlock(&pipe->lock);
 767
 768         p = gss_fill_context(p, end, ctx, gss_msg->auth->mech);
 769         if (IS_ERR(p)) {
 770                 err = PTR_ERR(p);
 771                 switch (err) {
 772                 case -EACCES:
 773                 case -EKEYEXPIRED:
 774                         gss_msg->msg.errno = err;
 775                         err = mlen;
 776                         break;
 777                 case -EFAULT:
 778                 case -ENOMEM:
 779                 case -EINVAL:
 780                 case -ENOSYS:
 781                         gss_msg->msg.errno = -EAGAIN;
 782                         break;
 783                 default:
 784                         printk(KERN_CRIT "%s: bad return from "
 785                                 "gss_fill_context: %zd\n", __func__, err);
 786                         gss_msg->msg.errno = -EIO;
 787                 }
 788                 goto err_release_msg;
 789         }
 790         gss_msg->ctx = gss_get_ctx(ctx);
 791         err = mlen;
 792
 793 err_release_msg:
 794         spin_lock(&pipe->lock);
 795         __gss_unhash_msg(gss_msg);
 796         spin_unlock(&pipe->lock);
 797         gss_release_msg(gss_msg);
 798 err_put_ctx:
 799         gss_put_ctx(ctx);
 800 err:
 801         kfree(buf);
 802 out:
 803         return err;
 804 }
 805
 806 static int gss_pipe_open(struct inode *inode, int new_version)
 807 {
 808         struct net *net = inode->i_sb->s_fs_info;
 809         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 810         int ret = 0;
 811
 812         spin_lock(&pipe_version_lock);
 813         if (sn->pipe_version < 0) {
 814                 /* First open of any gss pipe determines the version: */
 815                 sn->pipe_version = new_version;
 816                 rpc_wake_up(&pipe_version_rpc_waitqueue);
 817                 wake_up(&pipe_version_waitqueue);
 818         } else if (sn->pipe_version != new_version) {
 819                 /* Trying to open a pipe of a different version */
 820                 ret = -EBUSY;
 821                 goto out;
 822         }
 823         atomic_inc(&sn->pipe_users);
 824 out:
 825         spin_unlock(&pipe_version_lock);
 826         return ret;
 827
 828 }
 829
 830 static int gss_pipe_open_v0(struct inode *inode)
 831 {
 832         return gss_pipe_open(inode, 0);
 833 }
 834
 835 static int gss_pipe_open_v1(struct inode *inode)
 836 {
 837         return gss_pipe_open(inode, 1);
 838 }
 839
 840 static void
 841 gss_pipe_release(struct inode *inode)
 842 {
 843         struct net *net = inode->i_sb->s_fs_info;
 844         struct rpc_pipe *pipe = RPC_I(inode)->pipe;
 845         struct gss_upcall_msg *gss_msg;
 846
 847 restart:
 848         spin_lock(&pipe->lock);
 849         list_for_each_entry(gss_msg, &pipe->in_downcall, list) {
 850
 851                 if (!list_empty(&gss_msg->msg.list))
 852                         continue;
 853                 gss_msg->msg.errno = -EPIPE;
 854                 refcount_inc(&gss_msg->count);
 855                 __gss_unhash_msg(gss_msg);
 856                 spin_unlock(&pipe->lock);
 857                 gss_release_msg(gss_msg);
 858                 goto restart;
 859         }
 860         spin_unlock(&pipe->lock);
 861
 862         put_pipe_version(net);
 863 }
 864
 865 static void
 866 gss_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 867 {
 868         struct gss_upcall_msg *gss_msg = container_of(msg, struct gss_upcall_msg, msg);
 869
 870         if (msg->errno < 0) {
 871                 refcount_inc(&gss_msg->count);
 872                 gss_unhash_msg(gss_msg);
 873                 if (msg->errno == -ETIMEDOUT)
 874                         warn_gssd();
 875                 gss_release_msg(gss_msg);
 876         }
 877         gss_release_msg(gss_msg);
 878 }
 879
 880 static void gss_pipe_dentry_destroy(struct dentry *dir,
 881                 struct rpc_pipe_dir_object *pdo)
 882 {
 883         struct gss_pipe *gss_pipe = pdo->pdo_data;
 884         struct rpc_pipe *pipe = gss_pipe->pipe;
 885
 886         if (pipe->dentry != NULL) {
 887                 rpc_unlink(pipe->dentry);
 888                 pipe->dentry = NULL;
 889         }
 890 }
 891
 892 static int gss_pipe_dentry_create(struct dentry *dir,
 893                 struct rpc_pipe_dir_object *pdo)
 894 {
 895         struct gss_pipe *p = pdo->pdo_data;
 896         struct dentry *dentry;
 897
 898         dentry = rpc_mkpipe_dentry(dir, p->name, p->clnt, p->pipe);
 899         if (IS_ERR(dentry))
 900                 return PTR_ERR(dentry);
 901         p->pipe->dentry = dentry;
 902         return 0;
 903 }
 904
 905 static const struct rpc_pipe_dir_object_ops gss_pipe_dir_object_ops = {
 906         .create = gss_pipe_dentry_create,
 907         .destroy = gss_pipe_dentry_destroy,
 908 };
 909
 910 static struct gss_pipe *gss_pipe_alloc(struct rpc_clnt *clnt,
 911                 const char *name,
 912                 const struct rpc_pipe_ops *upcall_ops)
 913 {
 914         struct gss_pipe *p;
 915         int err = -ENOMEM;
 916
 917         p = kmalloc(sizeof(*p), GFP_KERNEL);
 918         if (p == NULL)
 919                 goto err;
 920         p->pipe = rpc_mkpipe_data(upcall_ops, RPC_PIPE_WAIT_FOR_OPEN);
 921         if (IS_ERR(p->pipe)) {
 922                 err = PTR_ERR(p->pipe);
 923                 goto err_free_gss_pipe;
 924         }
 925         p->name = name;
 926         p->clnt = clnt;
 927         kref_init(&p->kref);
 928         rpc_init_pipe_dir_object(&p->pdo,
 929                         &gss_pipe_dir_object_ops,
 930                         p);
 931         return p;
 932 err_free_gss_pipe:
 933         kfree(p);
 934 err:
 935         return ERR_PTR(err);
 936 }
 937
 938 struct gss_alloc_pdo {
 939         struct rpc_clnt *clnt;
 940         const char *name;
 941         const struct rpc_pipe_ops *upcall_ops;
 942 };
 943
 944 static int gss_pipe_match_pdo(struct rpc_pipe_dir_object *pdo, void *data)
 945 {
 946         struct gss_pipe *gss_pipe;
 947         struct gss_alloc_pdo *args = data;
 948
 949         if (pdo->pdo_ops != &gss_pipe_dir_object_ops)
 950                 return 0;
 951         gss_pipe = container_of(pdo, struct gss_pipe, pdo);
 952         if (strcmp(gss_pipe->name, args->name) != 0)
 953                 return 0;
 954         if (!kref_get_unless_zero(&gss_pipe->kref))
 955                 return 0;
 956         return 1;
 957 }
 958
 959 static struct rpc_pipe_dir_object *gss_pipe_alloc_pdo(void *data)
 960 {
 961         struct gss_pipe *gss_pipe;
 962         struct gss_alloc_pdo *args = data;
 963
 964         gss_pipe = gss_pipe_alloc(args->clnt, args->name, args->upcall_ops);
 965         if (!IS_ERR(gss_pipe))
 966                 return &gss_pipe->pdo;
 967         return NULL;
 968 }
 969
 970 static struct gss_pipe *gss_pipe_get(struct rpc_clnt *clnt,
 971                 const char *name,
 972                 const struct rpc_pipe_ops *upcall_ops)
 973 {
 974         struct net *net = rpc_net_ns(clnt);
 975         struct rpc_pipe_dir_object *pdo;
 976         struct gss_alloc_pdo args = {
 977                 .clnt = clnt,
 978                 .name = name,
 979                 .upcall_ops = upcall_ops,
 980         };
 981
 982         pdo = rpc_find_or_alloc_pipe_dir_object(net,
 983                         &clnt->cl_pipedir_objects,
 984                         gss_pipe_match_pdo,
 985                         gss_pipe_alloc_pdo,
 986                         &args);
 987         if (pdo != NULL)
 988                 return container_of(pdo, struct gss_pipe, pdo);
 989         return ERR_PTR(-ENOMEM);
 990 }
 991
 992 static void __gss_pipe_free(struct gss_pipe *p)
 993 {
 994         struct rpc_clnt *clnt = p->clnt;
 995         struct net *net = rpc_net_ns(clnt);
 996
 997         rpc_remove_pipe_dir_object(net,
 998                         &clnt->cl_pipedir_objects,
 999                         &p->pdo);
1000         rpc_destroy_pipe_data(p->pipe);
1001         kfree(p);
1002 }
1003
1004 static void __gss_pipe_release(struct kref *kref)
1005 {
1006         struct gss_pipe *p = container_of(kref, struct gss_pipe, kref);
1007
1008         __gss_pipe_free(p);
1009 }
1010
1011 static void gss_pipe_free(struct gss_pipe *p)
1012 {
1013         if (p != NULL)
1014                 kref_put(&p->kref, __gss_pipe_release);
1015 }
1016
1017 /*
1018  * NOTE: we have the opportunity to use different
1019  * parameters based on the input flavor (which must be a pseudoflavor)
1020  */
1021 static struct gss_auth *
1022 gss_create_new(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
1023 {
1024         rpc_authflavor_t flavor = args->pseudoflavor;
1025         struct gss_auth *gss_auth;
1026         struct gss_pipe *gss_pipe;
1027         struct rpc_auth * auth;
1028         int err = -ENOMEM; /* XXX? */
1029
1030         if (!try_module_get(THIS_MODULE))
1031                 return ERR_PTR(err);
1032         if (!(gss_auth = kmalloc(sizeof(*gss_auth), GFP_KERNEL)))
1033                 goto out_dec;
1034         INIT_HLIST_NODE(&gss_auth->hash);
1035         gss_auth->target_name = NULL;
1036         if (args->target_name) {
1037                 gss_auth->target_name = kstrdup(args->target_name, GFP_KERNEL);
1038                 if (gss_auth->target_name == NULL)
1039                         goto err_free;
1040         }
1041         gss_auth->client = clnt;
1042         gss_auth->net = get_net(rpc_net_ns(clnt));
1043         err = -EINVAL;
1044         gss_auth->mech = gss_mech_get_by_pseudoflavor(flavor);
1045         if (!gss_auth->mech)
1046                 goto err_put_net;
1047         gss_auth->service = gss_pseudoflavor_to_service(gss_auth->mech, flavor);
1048         if (gss_auth->service == 0)
1049                 goto err_put_mech;
1050         if (!gssd_running(gss_auth->net))
1051                 goto err_put_mech;
1052         auth = &gss_auth->rpc_auth;
1053         auth->au_cslack = GSS_CRED_SLACK >> 2;
1054         auth->au_rslack = GSS_KRB5_MAX_SLACK_NEEDED >> 2;
1055         auth->au_verfsize = GSS_VERF_SLACK >> 2;
1056         auth->au_ralign = GSS_VERF_SLACK >> 2;
1057         auth->au_flags = 0;
1058         auth->au_ops = &authgss_ops;
1059         auth->au_flavor = flavor;
1060         if (gss_pseudoflavor_to_datatouch(gss_auth->mech, flavor))
1061                 auth->au_flags |= RPCAUTH_AUTH_DATATOUCH;
1062         refcount_set(&auth->au_count, 1);
1063         kref_init(&gss_auth->kref);
1064
1065         err = rpcauth_init_credcache(auth);
1066         if (err)
1067                 goto err_put_mech;
1068         /*
1069          * Note: if we created the old pipe first, then someone who
1070          * examined the directory at the right moment might conclude
1071          * that we supported only the old pipe.  So we instead create
1072          * the new pipe first.
1073          */
1074         gss_pipe = gss_pipe_get(clnt, "gssd", &gss_upcall_ops_v1);
1075         if (IS_ERR(gss_pipe)) {
1076                 err = PTR_ERR(gss_pipe);
1077                 goto err_destroy_credcache;
1078         }
1079         gss_auth->gss_pipe[1] = gss_pipe;
1080
1081         gss_pipe = gss_pipe_get(clnt, gss_auth->mech->gm_name,
1082                         &gss_upcall_ops_v0);
1083         if (IS_ERR(gss_pipe)) {
1084                 err = PTR_ERR(gss_pipe);
1085                 goto err_destroy_pipe_1;
1086         }
1087         gss_auth->gss_pipe[0] = gss_pipe;
1088
1089         return gss_auth;
1090 err_destroy_pipe_1:
1091         gss_pipe_free(gss_auth->gss_pipe[1]);
1092 err_destroy_credcache:
1093         rpcauth_destroy_credcache(auth);
1094 err_put_mech:
1095         gss_mech_put(gss_auth->mech);
1096 err_put_net:
1097         put_net(gss_auth->net);
1098 err_free:
1099         kfree(gss_auth->target_name);
1100         kfree(gss_auth);
1101 out_dec:
1102         module_put(THIS_MODULE);
1103         trace_rpcgss_createauth(flavor, err);
1104         return ERR_PTR(err);
1105 }
1106
1107 static void
1108 gss_free(struct gss_auth *gss_auth)
1109 {
1110         gss_pipe_free(gss_auth->gss_pipe[0]);
1111         gss_pipe_free(gss_auth->gss_pipe[1]);
1112         gss_mech_put(gss_auth->mech);
1113         put_net(gss_auth->net);
1114         kfree(gss_auth->target_name);
1115
1116         kfree(gss_auth);
1117         module_put(THIS_MODULE);
1118 }
1119
1120 static void
1121 gss_free_callback(struct kref *kref)
1122 {
1123         struct gss_auth *gss_auth = container_of(kref, struct gss_auth, kref);
1124
1125         gss_free(gss_auth);
1126 }
1127
1128 static void
1129 gss_put_auth(struct gss_auth *gss_auth)
1130 {
1131         kref_put(&gss_auth->kref, gss_free_callback);
1132 }
1133
1134 static void
1135 gss_destroy(struct rpc_auth *auth)
1136 {
1137         struct gss_auth *gss_auth = container_of(auth,
1138                         struct gss_auth, rpc_auth);
1139
1140         if (hash_hashed(&gss_auth->hash)) {
1141                 spin_lock(&gss_auth_hash_lock);
1142                 hash_del(&gss_auth->hash);
1143                 spin_unlock(&gss_auth_hash_lock);
1144         }
1145
1146         gss_pipe_free(gss_auth->gss_pipe[0]);
1147         gss_auth->gss_pipe[0] = NULL;
1148         gss_pipe_free(gss_auth->gss_pipe[1]);
1149         gss_auth->gss_pipe[1] = NULL;
1150         rpcauth_destroy_credcache(auth);
1151
1152         gss_put_auth(gss_auth);
1153 }
1154
1155 /*
1156  * Auths may be shared between rpc clients that were cloned from a
1157  * common client with the same xprt, if they also share the flavor and
1158  * target_name.
1159  *
1160  * The auth is looked up from the oldest parent sharing the same
1161  * cl_xprt, and the auth itself references only that common parent
1162  * (which is guaranteed to last as long as any of its descendants).
1163  */
1164 static struct gss_auth *
1165 gss_auth_find_or_add_hashed(const struct rpc_auth_create_args *args,
1166                 struct rpc_clnt *clnt,
1167                 struct gss_auth *new)
1168 {
1169         struct gss_auth *gss_auth;
1170         unsigned long hashval = (unsigned long)clnt;
1171
1172         spin_lock(&gss_auth_hash_lock);
1173         hash_for_each_possible(gss_auth_hash_table,
1174                         gss_auth,
1175                         hash,
1176                         hashval) {
1177                 if (gss_auth->client != clnt)
1178                         continue;
1179                 if (gss_auth->rpc_auth.au_flavor != args->pseudoflavor)
1180                         continue;
1181                 if (gss_auth->target_name != args->target_name) {
1182                         if (gss_auth->target_name == NULL)
1183                                 continue;
1184                         if (args->target_name == NULL)
1185                                 continue;
1186                         if (strcmp(gss_auth->target_name, args->target_name))
1187                                 continue;
1188                 }
1189                 if (!refcount_inc_not_zero(&gss_auth->rpc_auth.au_count))
1190                         continue;
1191                 goto out;
1192         }
1193         if (new)
1194                 hash_add(gss_auth_hash_table, &new->hash, hashval);
1195         gss_auth = new;
1196 out:
1197         spin_unlock(&gss_auth_hash_lock);
1198         return gss_auth;
1199 }
1200
1201 static struct gss_auth *
1202 gss_create_hashed(const struct rpc_auth_create_args *args,
1203                   struct rpc_clnt *clnt)
1204 {
1205         struct gss_auth *gss_auth;
1206         struct gss_auth *new;
1207
1208         gss_auth = gss_auth_find_or_add_hashed(args, clnt, NULL);
1209         if (gss_auth != NULL)
1210                 goto out;
1211         new = gss_create_new(args, clnt);
1212         if (IS_ERR(new))
1213                 return new;
1214         gss_auth = gss_auth_find_or_add_hashed(args, clnt, new);
1215         if (gss_auth != new)
1216                 gss_destroy(&new->rpc_auth);
1217 out:
1218         return gss_auth;
1219 }
1220
1221 static struct rpc_auth *
1222 gss_create(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
1223 {
1224         struct gss_auth *gss_auth;
1225         struct rpc_xprt_switch *xps = rcu_access_pointer(clnt->cl_xpi.xpi_xpswitch);
1226
1227         while (clnt != clnt->cl_parent) {
1228                 struct rpc_clnt *parent = clnt->cl_parent;
1229                 /* Find the original parent for this transport */
1230                 if (rcu_access_pointer(parent->cl_xpi.xpi_xpswitch) != xps)
1231                         break;
1232                 clnt = parent;
1233         }
1234
1235         gss_auth = gss_create_hashed(args, clnt);
1236         if (IS_ERR(gss_auth))
1237                 return ERR_CAST(gss_auth);
1238         return &gss_auth->rpc_auth;
1239 }
1240
1241 static struct gss_cred *
1242 gss_dup_cred(struct gss_auth *gss_auth, struct gss_cred *gss_cred)
1243 {
1244         struct gss_cred *new;
1245
1246         /* Make a copy of the cred so that we can reference count it */
1247         new = kzalloc(sizeof(*gss_cred), GFP_NOFS);
1248         if (new) {
1249                 struct auth_cred acred = {
1250                         .cred = gss_cred->gc_base.cr_cred,
1251                 };
1252                 struct gss_cl_ctx *ctx =
1253                         rcu_dereference_protected(gss_cred->gc_ctx, 1);
1254
1255                 rpcauth_init_cred(&new->gc_base, &acred,
1256                                 &gss_auth->rpc_auth,
1257                                 &gss_nullops);
1258                 new->gc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
1259                 new->gc_service = gss_cred->gc_service;
1260                 new->gc_principal = gss_cred->gc_principal;
1261                 kref_get(&gss_auth->kref);
1262                 rcu_assign_pointer(new->gc_ctx, ctx);
1263                 gss_get_ctx(ctx);
1264         }
1265         return new;
1266 }
1267
1268 /*
1269  * gss_send_destroy_context will cause the RPCSEC_GSS to send a NULL RPC call
1270  * to the server with the GSS control procedure field set to
1271  * RPC_GSS_PROC_DESTROY. This should normally cause the server to release
1272  * all RPCSEC_GSS state associated with that context.
1273  */
1274 static void
1275 gss_send_destroy_context(struct rpc_cred *cred)
1276 {
1277         struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
1278         struct gss_auth *gss_auth = container_of(cred->cr_auth, struct gss_auth, rpc_auth);
1279         struct gss_cl_ctx *ctx = rcu_dereference_protected(gss_cred->gc_ctx, 1);
1280         struct gss_cred *new;
1281         struct rpc_task *task;
1282
1283         new = gss_dup_cred(gss_auth, gss_cred);
1284         if (new) {
1285                 ctx->gc_proc = RPC_GSS_PROC_DESTROY;
1286
1287                 task = rpc_call_null(gss_auth->client, &new->gc_base,
1288                                 RPC_TASK_ASYNC|RPC_TASK_SOFT);
1289                 if (!IS_ERR(task))
1290                         rpc_put_task(task);
1291
1292                 put_rpccred(&new->gc_base);
1293         }
1294 }
1295
1296 /* gss_destroy_cred (and gss_free_ctx) are used to clean up after failure
1297  * to create a new cred or context, so they check that things have been
1298  * allocated before freeing them. */
1299 static void
1300 gss_do_free_ctx(struct gss_cl_ctx *ctx)
1301 {
1302         gss_delete_sec_context(&ctx->gc_gss_ctx);
1303         kfree(ctx->gc_wire_ctx.data);
1304         kfree(ctx->gc_acceptor.data);
1305         kfree(ctx);
1306 }
1307
1308 static void
1309 gss_free_ctx_callback(struct rcu_head *head)
1310 {
1311         struct gss_cl_ctx *ctx = container_of(head, struct gss_cl_ctx, gc_rcu);
1312         gss_do_free_ctx(ctx);
1313 }
1314
1315 static void
1316 gss_free_ctx(struct gss_cl_ctx *ctx)
1317 {
1318         call_rcu(&ctx->gc_rcu, gss_free_ctx_callback);
1319 }
1320
1321 static void
1322 gss_free_cred(struct gss_cred *gss_cred)
1323 {
1324         kfree(gss_cred);
1325 }
1326
1327 static void
1328 gss_free_cred_callback(struct rcu_head *head)
1329 {
1330         struct gss_cred *gss_cred = container_of(head, struct gss_cred, gc_base.cr_rcu);
1331         gss_free_cred(gss_cred);
1332 }
1333
1334 static void
1335 gss_destroy_nullcred(struct rpc_cred *cred)
1336 {
1337         struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
1338         struct gss_auth *gss_auth = container_of(cred->cr_auth, struct gss_auth, rpc_auth);
1339         struct gss_cl_ctx *ctx = rcu_dereference_protected(gss_cred->gc_ctx, 1);
1340
1341         RCU_INIT_POINTER(gss_cred->gc_ctx, NULL);
1342         put_cred(cred->cr_cred);
1343         call_rcu(&cred->cr_rcu, gss_free_cred_callback);
1344         if (ctx)
1345                 gss_put_ctx(ctx);
1346         gss_put_auth(gss_auth);
1347 }
1348
1349 static void
1350 gss_destroy_cred(struct rpc_cred *cred)
1351 {
1352
1353         if (test_and_clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0)
1354                 gss_send_destroy_context(cred);
1355         gss_destroy_nullcred(cred);
1356 }
1357
1358 static int
1359 gss_hash_cred(struct auth_cred *acred, unsigned int hashbits)
1360 {
1361         return hash_64(from_kuid(&init_user_ns, acred->cred->fsuid), hashbits);
1362 }
1363
1364 /*
1365  * Lookup RPCSEC_GSS cred for the current process
1366  */
1367 static struct rpc_cred *
1368 gss_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
1369 {
1370         return rpcauth_lookup_credcache(auth, acred, flags, GFP_NOFS);
1371 }
1372
1373 static struct rpc_cred *
1374 gss_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags, gfp_t gfp)
1375 {
1376         struct gss_auth *gss_auth = container_of(auth, struct gss_auth, rpc_auth);
1377         struct gss_cred *cred = NULL;
1378         int err = -ENOMEM;
1379
1380         if (!(cred = kzalloc(sizeof(*cred), gfp)))
1381                 goto out_err;
1382
1383         rpcauth_init_cred(&cred->gc_base, acred, auth, &gss_credops);
1384         /*
1385          * Note: in order to force a call to call_refresh(), we deliberately
1386          * fail to flag the credential as RPCAUTH_CRED_UPTODATE.
1387          */
1388         cred->gc_base.cr_flags = 1UL << RPCAUTH_CRED_NEW;
1389         cred->gc_service = gss_auth->service;
1390         cred->gc_principal = acred->principal;
1391         kref_get(&gss_auth->kref);
1392         return &cred->gc_base;
1393
1394 out_err:
1395         return ERR_PTR(err);
1396 }
1397
1398 static int
1399 gss_cred_init(struct rpc_auth *auth, struct rpc_cred *cred)
1400 {
1401         struct gss_auth *gss_auth = container_of(auth, struct gss_auth, rpc_auth);
1402         struct gss_cred *gss_cred = container_of(cred,struct gss_cred, gc_base);
1403         int err;
1404
1405         do {
1406                 err = gss_create_upcall(gss_auth, gss_cred);
1407         } while (err == -EAGAIN);
1408         return err;
1409 }
1410
1411 static char *
1412 gss_stringify_acceptor(struct rpc_cred *cred)
1413 {
1414         char *string = NULL;
1415         struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
1416         struct gss_cl_ctx *ctx;
1417         unsigned int len;
1418         struct xdr_netobj *acceptor;
1419
1420         rcu_read_lock();
1421         ctx = rcu_dereference(gss_cred->gc_ctx);
1422         if (!ctx)
1423                 goto out;
1424
1425         len = ctx->gc_acceptor.len;
1426         rcu_read_unlock();
1427
1428         /* no point if there's no string */
1429         if (!len)
1430                 return NULL;
1431 realloc:
1432         string = kmalloc(len + 1, GFP_KERNEL);
1433         if (!string)
1434                 return NULL;
1435
1436         rcu_read_lock();
1437         ctx = rcu_dereference(gss_cred->gc_ctx);
1438
1439         /* did the ctx disappear or was it replaced by one with no acceptor? */
1440         if (!ctx || !ctx->gc_acceptor.len) {
1441                 kfree(string);
1442                 string = NULL;
1443                 goto out;
1444         }
1445
1446         acceptor = &ctx->gc_acceptor;
1447
1448         /*
1449          * Did we find a new acceptor that's longer than the original? Allocate
1450          * a longer buffer and try again.
1451          */
1452         if (len < acceptor->len) {
1453                 len = acceptor->len;
1454                 rcu_read_unlock();
1455                 kfree(string);
1456                 goto realloc;
1457         }
1458
1459         memcpy(string, acceptor->data, acceptor->len);
1460         string[acceptor->len] = '\0';
1461 out:
1462         rcu_read_unlock();
1463         return string;
1464 }
1465
1466 /*
1467  * Returns -EACCES if GSS context is NULL or will expire within the
1468  * timeout (miliseconds)
1469  */
1470 static int
1471 gss_key_timeout(struct rpc_cred *rc)
1472 {
1473         struct gss_cred *gss_cred = container_of(rc, struct gss_cred, gc_base);
1474         struct gss_cl_ctx *ctx;
1475         unsigned long timeout = jiffies + (gss_key_expire_timeo * HZ);
1476         int ret = 0;
1477
1478         rcu_read_lock();
1479         ctx = rcu_dereference(gss_cred->gc_ctx);
1480         if (!ctx || time_after(timeout, ctx->gc_expiry))
1481                 ret = -EACCES;
1482         rcu_read_unlock();
1483
1484         return ret;
1485 }
1486
1487 static int
1488 gss_match(struct auth_cred *acred, struct rpc_cred *rc, int flags)
1489 {
1490         struct gss_cred *gss_cred = container_of(rc, struct gss_cred, gc_base);
1491         struct gss_cl_ctx *ctx;
1492         int ret;
1493
1494         if (test_bit(RPCAUTH_CRED_NEW, &rc->cr_flags))
1495                 goto out;
1496         /* Don't match with creds that have expired. */
1497         rcu_read_lock();
1498         ctx = rcu_dereference(gss_cred->gc_ctx);
1499         if (!ctx || time_after(jiffies, ctx->gc_expiry)) {
1500                 rcu_read_unlock();
1501                 return 0;
1502         }
1503         rcu_read_unlock();
1504         if (!test_bit(RPCAUTH_CRED_UPTODATE, &rc->cr_flags))
1505                 return 0;
1506 out:
1507         if (acred->principal != NULL) {
1508                 if (gss_cred->gc_principal == NULL)
1509                         return 0;
1510                 ret = strcmp(acred->principal, gss_cred->gc_principal) == 0;
1511         } else {
1512                 if (gss_cred->gc_principal != NULL)
1513                         return 0;
1514                 ret = uid_eq(rc->cr_cred->fsuid, acred->cred->fsuid);
1515         }
1516         return ret;
1517 }
1518
1519 /*
1520  * Marshal credentials.
1521  *
1522  * The expensive part is computing the verifier. We can't cache a
1523  * pre-computed version of the verifier because the seqno, which
1524  * is different every time, is included in the MIC.
1525  */
1526 static int gss_marshal(struct rpc_task *task, struct xdr_stream *xdr)
1527 {
1528         struct rpc_rqst *req = task->tk_rqstp;
1529         struct rpc_cred *cred = req->rq_cred;
1530         struct gss_cred *gss_cred = container_of(cred, struct gss_cred,
1531                                                  gc_base);
1532         struct gss_cl_ctx       *ctx = gss_cred_get_ctx(cred);
1533         __be32          *p, *cred_len;
1534         u32             maj_stat = 0;
1535         struct xdr_netobj mic;
1536         struct kvec     iov;
1537         struct xdr_buf  verf_buf;
1538         int status;
1539
1540         /* Credential */
1541
1542         p = xdr_reserve_space(xdr, 7 * sizeof(*p) +
1543                               ctx->gc_wire_ctx.len);
1544         if (!p)
1545                 goto marshal_failed;
1546         *p++ = rpc_auth_gss;
1547         cred_len = p++;
1548
1549         spin_lock(&ctx->gc_seq_lock);
1550         req->rq_seqno = (ctx->gc_seq < MAXSEQ) ? ctx->gc_seq++ : MAXSEQ;
1551         spin_unlock(&ctx->gc_seq_lock);
1552         if (req->rq_seqno == MAXSEQ)
1553                 goto expired;
1554         trace_rpcgss_seqno(task);
1555
1556         *p++ = cpu_to_be32(RPC_GSS_VERSION);
1557         *p++ = cpu_to_be32(ctx->gc_proc);
1558         *p++ = cpu_to_be32(req->rq_seqno);
1559         *p++ = cpu_to_be32(gss_cred->gc_service);
1560         p = xdr_encode_netobj(p, &ctx->gc_wire_ctx);
1561         *cred_len = cpu_to_be32((p - (cred_len + 1)) << 2);
1562
1563         /* Verifier */
1564
1565         /* We compute the checksum for the verifier over the xdr-encoded bytes
1566          * starting with the xid and ending at the end of the credential: */
1567         iov.iov_base = req->rq_snd_buf.head[0].iov_base;
1568         iov.iov_len = (u8 *)p - (u8 *)iov.iov_base;
1569         xdr_buf_from_iov(&iov, &verf_buf);
1570
1571         p = xdr_reserve_space(xdr, sizeof(*p));
1572         if (!p)
1573                 goto marshal_failed;
1574         *p++ = rpc_auth_gss;
1575         mic.data = (u8 *)(p + 1);
1576         maj_stat = gss_get_mic(ctx->gc_gss_ctx, &verf_buf, &mic);
1577         if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1578                 goto expired;
1579         else if (maj_stat != 0)
1580                 goto bad_mic;
1581         if (xdr_stream_encode_opaque_inline(xdr, (void **)&p, mic.len) < 0)
1582                 goto marshal_failed;
1583         status = 0;
1584 out:
1585         gss_put_ctx(ctx);
1586         return status;
1587 expired:
1588         clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1589         status = -EKEYEXPIRED;
1590         goto out;
1591 marshal_failed:
1592         status = -EMSGSIZE;
1593         goto out;
1594 bad_mic:
1595         trace_rpcgss_get_mic(task, maj_stat);
1596         status = -EIO;
1597         goto out;
1598 }
1599
1600 static int gss_renew_cred(struct rpc_task *task)
1601 {
1602         struct rpc_cred *oldcred = task->tk_rqstp->rq_cred;
1603         struct gss_cred *gss_cred = container_of(oldcred,
1604                                                  struct gss_cred,
1605                                                  gc_base);
1606         struct rpc_auth *auth = oldcred->cr_auth;
1607         struct auth_cred acred = {
1608                 .cred = oldcred->cr_cred,
1609                 .principal = gss_cred->gc_principal,
1610         };
1611         struct rpc_cred *new;
1612
1613         new = gss_lookup_cred(auth, &acred, RPCAUTH_LOOKUP_NEW);
1614         if (IS_ERR(new))
1615                 return PTR_ERR(new);
1616         task->tk_rqstp->rq_cred = new;
1617         put_rpccred(oldcred);
1618         return 0;
1619 }
1620
1621 static int gss_cred_is_negative_entry(struct rpc_cred *cred)
1622 {
1623         if (test_bit(RPCAUTH_CRED_NEGATIVE, &cred->cr_flags)) {
1624                 unsigned long now = jiffies;
1625                 unsigned long begin, expire;
1626                 struct gss_cred *gss_cred;
1627
1628                 gss_cred = container_of(cred, struct gss_cred, gc_base);
1629                 begin = gss_cred->gc_upcall_timestamp;
1630                 expire = begin + gss_expired_cred_retry_delay * HZ;
1631
1632                 if (time_in_range_open(now, begin, expire))
1633                         return 1;
1634         }
1635         return 0;
1636 }
1637
1638 /*
1639 * Refresh credentials. XXX - finish
1640 */
1641 static int
1642 gss_refresh(struct rpc_task *task)
1643 {
1644         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
1645         int ret = 0;
1646
1647         if (gss_cred_is_negative_entry(cred))
1648                 return -EKEYEXPIRED;
1649
1650         if (!test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags) &&
1651                         !test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags)) {
1652                 ret = gss_renew_cred(task);
1653                 if (ret < 0)
1654                         goto out;
1655                 cred = task->tk_rqstp->rq_cred;
1656         }
1657
1658         if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags))
1659                 ret = gss_refresh_upcall(task);
1660 out:
1661         return ret;
1662 }
1663
1664 /* Dummy refresh routine: used only when destroying the context */
1665 static int
1666 gss_refresh_null(struct rpc_task *task)
1667 {
1668         return 0;
1669 }
1670
1671 static int
1672 gss_validate(struct rpc_task *task, struct xdr_stream *xdr)
1673 {
1674         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
1675         struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
1676         __be32          *p, *seq = NULL;
1677         struct kvec     iov;
1678         struct xdr_buf  verf_buf;
1679         struct xdr_netobj mic;
1680         u32             len, maj_stat;
1681         int             status;
1682
1683         p = xdr_inline_decode(xdr, 2 * sizeof(*p));
1684         if (!p)
1685                 goto validate_failed;
1686         if (*p++ != rpc_auth_gss)
1687                 goto validate_failed;
1688         len = be32_to_cpup(p);
1689         if (len > RPC_MAX_AUTH_SIZE)
1690                 goto validate_failed;
1691         p = xdr_inline_decode(xdr, len);
1692         if (!p)
1693                 goto validate_failed;
1694
1695         seq = kmalloc(4, GFP_NOFS);
1696         if (!seq)
1697                 goto validate_failed;
1698         *seq = cpu_to_be32(task->tk_rqstp->rq_seqno);
1699         iov.iov_base = seq;
1700         iov.iov_len = 4;
1701         xdr_buf_from_iov(&iov, &verf_buf);
1702         mic.data = (u8 *)p;
1703         mic.len = len;
1704         maj_stat = gss_verify_mic(ctx->gc_gss_ctx, &verf_buf, &mic);
1705         if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1706                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1707         if (maj_stat)
1708                 goto bad_mic;
1709
1710         /* We leave it to unwrap to calculate au_rslack. For now we just
1711          * calculate the length of the verifier: */
1712         cred->cr_auth->au_verfsize = XDR_QUADLEN(len) + 2;
1713         status = 0;
1714 out:
1715         gss_put_ctx(ctx);
1716         kfree(seq);
1717         return status;
1718
1719 validate_failed:
1720         status = -EIO;
1721         goto out;
1722 bad_mic:
1723         trace_rpcgss_verify_mic(task, maj_stat);
1724         status = -EACCES;
1725         goto out;
1726 }
1727
1728 static noinline_for_stack int
1729 gss_wrap_req_integ(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
1730                    struct rpc_task *task, struct xdr_stream *xdr)
1731 {
1732         struct rpc_rqst *rqstp = task->tk_rqstp;
1733         struct xdr_buf integ_buf, *snd_buf = &rqstp->rq_snd_buf;
1734         struct xdr_netobj mic;
1735         __be32 *p, *integ_len;
1736         u32 offset, maj_stat;
1737
1738         p = xdr_reserve_space(xdr, 2 * sizeof(*p));
1739         if (!p)
1740                 goto wrap_failed;
1741         integ_len = p++;
1742         *p = cpu_to_be32(rqstp->rq_seqno);
1743
1744         if (rpcauth_wrap_req_encode(task, xdr))
1745                 goto wrap_failed;
1746
1747         offset = (u8 *)p - (u8 *)snd_buf->head[0].iov_base;
1748         if (xdr_buf_subsegment(snd_buf, &integ_buf,
1749                                 offset, snd_buf->len - offset))
1750                 goto wrap_failed;
1751         *integ_len = cpu_to_be32(integ_buf.len);
1752
1753         p = xdr_reserve_space(xdr, 0);
1754         if (!p)
1755                 goto wrap_failed;
1756         mic.data = (u8 *)(p + 1);
1757         maj_stat = gss_get_mic(ctx->gc_gss_ctx, &integ_buf, &mic);
1758         if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1759                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1760         else if (maj_stat)
1761                 goto bad_mic;
1762         /* Check that the trailing MIC fit in the buffer, after the fact */
1763         if (xdr_stream_encode_opaque_inline(xdr, (void **)&p, mic.len) < 0)
1764                 goto wrap_failed;
1765         return 0;
1766 wrap_failed:
1767         return -EMSGSIZE;
1768 bad_mic:
1769         trace_rpcgss_get_mic(task, maj_stat);
1770         return -EIO;
1771 }
1772
1773 static void
1774 priv_release_snd_buf(struct rpc_rqst *rqstp)
1775 {
1776         int i;
1777
1778         for (i=0; i < rqstp->rq_enc_pages_num; i++)
1779                 __free_page(rqstp->rq_enc_pages[i]);
1780         kfree(rqstp->rq_enc_pages);
1781         rqstp->rq_release_snd_buf = NULL;
1782 }
1783
1784 static int
1785 alloc_enc_pages(struct rpc_rqst *rqstp)
1786 {
1787         struct xdr_buf *snd_buf = &rqstp->rq_snd_buf;
1788         int first, last, i;
1789
1790         if (rqstp->rq_release_snd_buf)
1791                 rqstp->rq_release_snd_buf(rqstp);
1792
1793         if (snd_buf->page_len == 0) {
1794                 rqstp->rq_enc_pages_num = 0;
1795                 return 0;
1796         }
1797
1798         first = snd_buf->page_base >> PAGE_SHIFT;
1799         last = (snd_buf->page_base + snd_buf->page_len - 1) >> PAGE_SHIFT;
1800         rqstp->rq_enc_pages_num = last - first + 1 + 1;
1801         rqstp->rq_enc_pages
1802                 = kmalloc_array(rqstp->rq_enc_pages_num,
1803                                 sizeof(struct page *),
1804                                 GFP_NOFS);
1805         if (!rqstp->rq_enc_pages)
1806                 goto out;
1807         for (i=0; i < rqstp->rq_enc_pages_num; i++) {
1808                 rqstp->rq_enc_pages[i] = alloc_page(GFP_NOFS);
1809                 if (rqstp->rq_enc_pages[i] == NULL)
1810                         goto out_free;
1811         }
1812         rqstp->rq_release_snd_buf = priv_release_snd_buf;
1813         return 0;
1814 out_free:
1815         rqstp->rq_enc_pages_num = i;
1816         priv_release_snd_buf(rqstp);
1817 out:
1818         return -EAGAIN;
1819 }
1820
1821 static noinline_for_stack int
1822 gss_wrap_req_priv(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
1823                   struct rpc_task *task, struct xdr_stream *xdr)
1824 {
1825         struct rpc_rqst *rqstp = task->tk_rqstp;
1826         struct xdr_buf  *snd_buf = &rqstp->rq_snd_buf;
1827         u32             pad, offset, maj_stat;
1828         int             status;
1829         __be32          *p, *opaque_len;
1830         struct page     **inpages;
1831         int             first;
1832         struct kvec     *iov;
1833
1834         status = -EIO;
1835         p = xdr_reserve_space(xdr, 2 * sizeof(*p));
1836         if (!p)
1837                 goto wrap_failed;
1838         opaque_len = p++;
1839         *p = cpu_to_be32(rqstp->rq_seqno);
1840
1841         if (rpcauth_wrap_req_encode(task, xdr))
1842                 goto wrap_failed;
1843
1844         status = alloc_enc_pages(rqstp);
1845         if (unlikely(status))
1846                 goto wrap_failed;
1847         first = snd_buf->page_base >> PAGE_SHIFT;
1848         inpages = snd_buf->pages + first;
1849         snd_buf->pages = rqstp->rq_enc_pages;
1850         snd_buf->page_base -= first << PAGE_SHIFT;
1851         /*
1852          * Move the tail into its own page, in case gss_wrap needs
1853          * more space in the head when wrapping.
1854          *
1855          * Still... Why can't gss_wrap just slide the tail down?
1856          */
1857         if (snd_buf->page_len || snd_buf->tail[0].iov_len) {
1858                 char *tmp;
1859
1860                 tmp = page_address(rqstp->rq_enc_pages[rqstp->rq_enc_pages_num - 1]);
1861                 memcpy(tmp, snd_buf->tail[0].iov_base, snd_buf->tail[0].iov_len);
1862                 snd_buf->tail[0].iov_base = tmp;
1863         }
1864         offset = (u8 *)p - (u8 *)snd_buf->head[0].iov_base;
1865         maj_stat = gss_wrap(ctx->gc_gss_ctx, offset, snd_buf, inpages);
1866         /* slack space should prevent this ever happening: */
1867         if (unlikely(snd_buf->len > snd_buf->buflen))
1868                 goto wrap_failed;
1869         /* We're assuming that when GSS_S_CONTEXT_EXPIRED, the encryption was
1870          * done anyway, so it's safe to put the request on the wire: */
1871         if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1872                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1873         else if (maj_stat)
1874                 goto bad_wrap;
1875
1876         *opaque_len = cpu_to_be32(snd_buf->len - offset);
1877         /* guess whether the pad goes into the head or the tail: */
1878         if (snd_buf->page_len || snd_buf->tail[0].iov_len)
1879                 iov = snd_buf->tail;
1880         else
1881                 iov = snd_buf->head;
1882         p = iov->iov_base + iov->iov_len;
1883         pad = xdr_pad_size(snd_buf->len - offset);
1884         memset(p, 0, pad);
1885         iov->iov_len += pad;
1886         snd_buf->len += pad;
1887
1888         return 0;
1889 wrap_failed:
1890         return status;
1891 bad_wrap:
1892         trace_rpcgss_wrap(task, maj_stat);
1893         return -EIO;
1894 }
1895
1896 static int gss_wrap_req(struct rpc_task *task, struct xdr_stream *xdr)
1897 {
1898         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
1899         struct gss_cred *gss_cred = container_of(cred, struct gss_cred,
1900                         gc_base);
1901         struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
1902         int status;
1903
1904         status = -EIO;
1905         if (ctx->gc_proc != RPC_GSS_PROC_DATA) {
1906                 /* The spec seems a little ambiguous here, but I think that not
1907                  * wrapping context destruction requests makes the most sense.
1908                  */
1909                 status = rpcauth_wrap_req_encode(task, xdr);
1910                 goto out;
1911         }
1912         switch (gss_cred->gc_service) {
1913         case RPC_GSS_SVC_NONE:
1914                 status = rpcauth_wrap_req_encode(task, xdr);
1915                 break;
1916         case RPC_GSS_SVC_INTEGRITY:
1917                 status = gss_wrap_req_integ(cred, ctx, task, xdr);
1918                 break;
1919         case RPC_GSS_SVC_PRIVACY:
1920                 status = gss_wrap_req_priv(cred, ctx, task, xdr);
1921                 break;
1922         default:
1923                 status = -EIO;
1924         }
1925 out:
1926         gss_put_ctx(ctx);
1927         return status;
1928 }
1929
1930 static int
1931 gss_unwrap_resp_auth(struct rpc_cred *cred)
1932 {
1933         struct rpc_auth *auth = cred->cr_auth;
1934
1935         auth->au_rslack = auth->au_verfsize;
1936         auth->au_ralign = auth->au_verfsize;
1937         return 0;
1938 }
1939
1940 /*
1941  * RFC 2203, Section 5.3.2.2
1942  *
1943  *      struct rpc_gss_integ_data {
1944  *              opaque databody_integ<>;
1945  *              opaque checksum<>;
1946  *      };
1947  *
1948  *      struct rpc_gss_data_t {
1949  *              unsigned int seq_num;
1950  *              proc_req_arg_t arg;
1951  *      };
1952  */
1953 static noinline_for_stack int
1954 gss_unwrap_resp_integ(struct rpc_task *task, struct rpc_cred *cred,
1955                       struct gss_cl_ctx *ctx, struct rpc_rqst *rqstp,
1956                       struct xdr_stream *xdr)
1957 {
1958         struct xdr_buf gss_data, *rcv_buf = &rqstp->rq_rcv_buf;
1959         struct rpc_auth *auth = cred->cr_auth;
1960         u32 len, offset, seqno, maj_stat;
1961         struct xdr_netobj mic;
1962         int ret;
1963
1964         ret = -EIO;
1965         mic.data = NULL;
1966
1967         /* opaque databody_integ<>; */
1968         if (xdr_stream_decode_u32(xdr, &len))
1969                 goto unwrap_failed;
1970         if (len & 3)
1971                 goto unwrap_failed;
1972         offset = rcv_buf->len - xdr_stream_remaining(xdr);
1973         if (xdr_stream_decode_u32(xdr, &seqno))
1974                 goto unwrap_failed;
1975         if (seqno != rqstp->rq_seqno)
1976                 goto bad_seqno;
1977         if (xdr_buf_subsegment(rcv_buf, &gss_data, offset, len))
1978                 goto unwrap_failed;
1979
1980         /*
1981          * The xdr_stream now points to the beginning of the
1982          * upper layer payload, to be passed below to
1983          * rpcauth_unwrap_resp_decode(). The checksum, which
1984          * follows the upper layer payload in @rcv_buf, is
1985          * located and parsed without updating the xdr_stream.
1986          */
1987
1988         /* opaque checksum<>; */
1989         offset += len;
1990         if (xdr_decode_word(rcv_buf, offset, &len))
1991                 goto unwrap_failed;
1992         offset += sizeof(__be32);
1993         if (offset + len > rcv_buf->len)
1994                 goto unwrap_failed;
1995         mic.len = len;
1996         mic.data = kmalloc(len, GFP_NOFS);
1997         if (!mic.data)
1998                 goto unwrap_failed;
1999         if (read_bytes_from_xdr_buf(rcv_buf, offset, mic.data, mic.len))
2000                 goto unwrap_failed;
2001
2002         maj_stat = gss_verify_mic(ctx->gc_gss_ctx, &gss_data, &mic);
2003         if (maj_stat == GSS_S_CONTEXT_EXPIRED)
2004                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
2005         if (maj_stat != GSS_S_COMPLETE)
2006                 goto bad_mic;
2007
2008         auth->au_rslack = auth->au_verfsize + 2 + 1 + XDR_QUADLEN(mic.len);
2009         auth->au_ralign = auth->au_verfsize + 2;
2010         ret = 0;
2011
2012 out:
2013         kfree(mic.data);
2014         return ret;
2015
2016 unwrap_failed:
2017         trace_rpcgss_unwrap_failed(task);
2018         goto out;
2019 bad_seqno:
2020         trace_rpcgss_bad_seqno(task, rqstp->rq_seqno, seqno);
2021         goto out;
2022 bad_mic:
2023         trace_rpcgss_verify_mic(task, maj_stat);
2024         goto out;
2025 }
2026
2027 static noinline_for_stack int
2028 gss_unwrap_resp_priv(struct rpc_task *task, struct rpc_cred *cred,
2029                      struct gss_cl_ctx *ctx, struct rpc_rqst *rqstp,
2030                      struct xdr_stream *xdr)
2031 {
2032         struct xdr_buf *rcv_buf = &rqstp->rq_rcv_buf;
2033         struct kvec *head = rqstp->rq_rcv_buf.head;
2034         struct rpc_auth *auth = cred->cr_auth;
2035         unsigned int savedlen = rcv_buf->len;
2036         u32 offset, opaque_len, maj_stat;
2037         __be32 *p;
2038
2039         p = xdr_inline_decode(xdr, 2 * sizeof(*p));
2040         if (unlikely(!p))
2041                 goto unwrap_failed;
2042         opaque_len = be32_to_cpup(p++);
2043         offset = (u8 *)(p) - (u8 *)head->iov_base;
2044         if (offset + opaque_len > rcv_buf->len)
2045                 goto unwrap_failed;
2046         rcv_buf->len = offset + opaque_len;
2047
2048         maj_stat = gss_unwrap(ctx->gc_gss_ctx, offset, rcv_buf);
2049         if (maj_stat == GSS_S_CONTEXT_EXPIRED)
2050                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
2051         if (maj_stat != GSS_S_COMPLETE)
2052                 goto bad_unwrap;
2053         /* gss_unwrap decrypted the sequence number */
2054         if (be32_to_cpup(p++) != rqstp->rq_seqno)
2055                 goto bad_seqno;
2056
2057         /* gss_unwrap redacts the opaque blob from the head iovec.
2058          * rcv_buf has changed, thus the stream needs to be reset.
2059          */
2060         xdr_init_decode(xdr, rcv_buf, p, rqstp);
2061
2062         auth->au_rslack = auth->au_verfsize + 2 +
2063                           XDR_QUADLEN(savedlen - rcv_buf->len);
2064         auth->au_ralign = auth->au_verfsize + 2 +
2065                           XDR_QUADLEN(savedlen - rcv_buf->len);
2066         return 0;
2067 unwrap_failed:
2068         trace_rpcgss_unwrap_failed(task);
2069         return -EIO;
2070 bad_seqno:
2071         trace_rpcgss_bad_seqno(task, rqstp->rq_seqno, be32_to_cpup(--p));
2072         return -EIO;
2073 bad_unwrap:
2074         trace_rpcgss_unwrap(task, maj_stat);
2075         return -EIO;
2076 }
2077
2078 static bool
2079 gss_seq_is_newer(u32 new, u32 old)
2080 {
2081         return (s32)(new - old) > 0;
2082 }
2083
2084 static bool
2085 gss_xmit_need_reencode(struct rpc_task *task)
2086 {
2087         struct rpc_rqst *req = task->tk_rqstp;
2088         struct rpc_cred *cred = req->rq_cred;
2089         struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
2090         u32 win, seq_xmit = 0;
2091         bool ret = true;
2092
2093         if (!ctx)
2094                 goto out;
2095
2096         if (gss_seq_is_newer(req->rq_seqno, READ_ONCE(ctx->gc_seq)))
2097                 goto out_ctx;
2098
2099         seq_xmit = READ_ONCE(ctx->gc_seq_xmit);
2100         while (gss_seq_is_newer(req->rq_seqno, seq_xmit)) {
2101                 u32 tmp = seq_xmit;
2102
2103                 seq_xmit = cmpxchg(&ctx->gc_seq_xmit, tmp, req->rq_seqno);
2104                 if (seq_xmit == tmp) {
2105                         ret = false;
2106                         goto out_ctx;
2107                 }
2108         }
2109
2110         win = ctx->gc_win;
2111         if (win > 0)
2112                 ret = !gss_seq_is_newer(req->rq_seqno, seq_xmit - win);
2113
2114 out_ctx:
2115         gss_put_ctx(ctx);
2116 out:
2117         trace_rpcgss_need_reencode(task, seq_xmit, ret);
2118         return ret;
2119 }
2120
2121 static int
2122 gss_unwrap_resp(struct rpc_task *task, struct xdr_stream *xdr)
2123 {
2124         struct rpc_rqst *rqstp = task->tk_rqstp;
2125         struct rpc_cred *cred = rqstp->rq_cred;
2126         struct gss_cred *gss_cred = container_of(cred, struct gss_cred,
2127                         gc_base);
2128         struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
2129         int status = -EIO;
2130
2131         if (ctx->gc_proc != RPC_GSS_PROC_DATA)
2132                 goto out_decode;
2133         switch (gss_cred->gc_service) {
2134         case RPC_GSS_SVC_NONE:
2135                 status = gss_unwrap_resp_auth(cred);
2136                 break;
2137         case RPC_GSS_SVC_INTEGRITY:
2138                 status = gss_unwrap_resp_integ(task, cred, ctx, rqstp, xdr);
2139                 break;
2140         case RPC_GSS_SVC_PRIVACY:
2141                 status = gss_unwrap_resp_priv(task, cred, ctx, rqstp, xdr);
2142                 break;
2143         }
2144         if (status)
2145                 goto out;
2146
2147 out_decode:
2148         status = rpcauth_unwrap_resp_decode(task, xdr);
2149 out:
2150         gss_put_ctx(ctx);
2151         return status;
2152 }
2153
2154 static const struct rpc_authops authgss_ops = {
2155         .owner          = THIS_MODULE,
2156         .au_flavor      = RPC_AUTH_GSS,
2157         .au_name        = "RPCSEC_GSS",
2158         .create         = gss_create,
2159         .destroy        = gss_destroy,
2160         .hash_cred      = gss_hash_cred,
2161         .lookup_cred    = gss_lookup_cred,
2162         .crcreate       = gss_create_cred,
2163         .info2flavor    = gss_mech_info2flavor,
2164         .flavor2info    = gss_mech_flavor2info,
2165 };
2166
2167 static const struct rpc_credops gss_credops = {
2168         .cr_name                = "AUTH_GSS",
2169         .crdestroy              = gss_destroy_cred,
2170         .cr_init                = gss_cred_init,
2171         .crmatch                = gss_match,
2172         .crmarshal              = gss_marshal,
2173         .crrefresh              = gss_refresh,
2174         .crvalidate             = gss_validate,
2175         .crwrap_req             = gss_wrap_req,
2176         .crunwrap_resp          = gss_unwrap_resp,
2177         .crkey_timeout          = gss_key_timeout,
2178         .crstringify_acceptor   = gss_stringify_acceptor,
2179         .crneed_reencode        = gss_xmit_need_reencode,
2180 };
2181
2182 static const struct rpc_credops gss_nullops = {
2183         .cr_name                = "AUTH_GSS",
2184         .crdestroy              = gss_destroy_nullcred,
2185         .crmatch                = gss_match,
2186         .crmarshal              = gss_marshal,
2187         .crrefresh              = gss_refresh_null,
2188         .crvalidate             = gss_validate,
2189         .crwrap_req             = gss_wrap_req,
2190         .crunwrap_resp          = gss_unwrap_resp,
2191         .crstringify_acceptor   = gss_stringify_acceptor,
2192 };
2193
2194 static const struct rpc_pipe_ops gss_upcall_ops_v0 = {
2195         .upcall         = gss_v0_upcall,
2196         .downcall       = gss_pipe_downcall,
2197         .destroy_msg    = gss_pipe_destroy_msg,
2198         .open_pipe      = gss_pipe_open_v0,
2199         .release_pipe   = gss_pipe_release,
2200 };
2201
2202 static const struct rpc_pipe_ops gss_upcall_ops_v1 = {
2203         .upcall         = gss_v1_upcall,
2204         .downcall       = gss_pipe_downcall,
2205         .destroy_msg    = gss_pipe_destroy_msg,
2206         .open_pipe      = gss_pipe_open_v1,
2207         .release_pipe   = gss_pipe_release,
2208 };
2209
2210 static __net_init int rpcsec_gss_init_net(struct net *net)
2211 {
2212         return gss_svc_init_net(net);
2213 }
2214
2215 static __net_exit void rpcsec_gss_exit_net(struct net *net)
2216 {
2217         gss_svc_shutdown_net(net);
2218 }
2219
2220 static struct pernet_operations rpcsec_gss_net_ops = {
2221         .init = rpcsec_gss_init_net,
2222         .exit = rpcsec_gss_exit_net,
2223 };
2224
2225 /*
2226  * Initialize RPCSEC_GSS module
2227  */
2228 static int __init init_rpcsec_gss(void)
2229 {
2230         int err = 0;
2231
2232         err = rpcauth_register(&authgss_ops);
2233         if (err)
2234                 goto out;
2235         err = gss_svc_init();
2236         if (err)
2237                 goto out_unregister;
2238         err = register_pernet_subsys(&rpcsec_gss_net_ops);
2239         if (err)
2240                 goto out_svc_exit;
2241         rpc_init_wait_queue(&pipe_version_rpc_waitqueue, "gss pipe version");
2242         return 0;
2243 out_svc_exit:
2244         gss_svc_shutdown();
2245 out_unregister:
2246         rpcauth_unregister(&authgss_ops);
2247 out:
2248         return err;
2249 }
2250
2251 static void __exit exit_rpcsec_gss(void)
2252 {
2253         unregister_pernet_subsys(&rpcsec_gss_net_ops);
2254         gss_svc_shutdown();
2255         rpcauth_unregister(&authgss_ops);
2256         rcu_barrier(); /* Wait for completion of call_rcu()'s */
2257 }
2258
2259 MODULE_ALIAS("rpc-auth-6");
2260 MODULE_LICENSE("GPL");
2261 module_param_named(expired_cred_retry_delay,
2262                    gss_expired_cred_retry_delay,
2263                    uint, 0644);
2264 MODULE_PARM_DESC(expired_cred_retry_delay, "Timeout (in seconds) until "
2265                 "the RPC engine retries an expired credential");
2266
2267 module_param_named(key_expire_timeo,
2268                    gss_key_expire_timeo,
2269                    uint, 0644);
2270 MODULE_PARM_DESC(key_expire_timeo, "Time (in seconds) at the end of a "
2271                 "credential keys lifetime where the NFS layer cleans up "
2272                 "prior to key expiration");
2273
2274 module_init(init_rpcsec_gss)
2275 module_exit(exit_rpcsec_gss)