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