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 /*
  53  * This compile-time check verifies that we will not exceed the
  54  * slack space allotted by the client and server auth_gss code
  55  * before they call gss_wrap().
  56  */
  57 #define GSS_KRB5_MAX_SLACK_NEEDED                                       \
  58         (GSS_KRB5_TOK_HDR_LEN           /* gss token header */          \
  59         + GSS_KRB5_MAX_CKSUM_LEN        /* gss token checksum */        \
  60         + GSS_KRB5_MAX_BLOCKSIZE        /* confounder */                \
  61         + GSS_KRB5_MAX_BLOCKSIZE        /* possible padding */          \
  62         + GSS_KRB5_TOK_HDR_LEN          /* encrypted hdr in v2 token */ \
  63         + GSS_KRB5_MAX_CKSUM_LEN        /* encryption hmac */           \
  64         + XDR_UNIT * 2                  /* RPC verifier */              \
  65         + GSS_KRB5_TOK_HDR_LEN                                          \
  66         + GSS_KRB5_MAX_CKSUM_LEN)
  67
  68 #define GSS_CRED_SLACK          (RPC_MAX_AUTH_SIZE * 2)
  69 /* length of a krb5 verifier (48), plus data added before arguments when
  70  * using integrity (two 4-byte integers): */
  71 #define GSS_VERF_SLACK          100
  72
  73 static DEFINE_HASHTABLE(gss_auth_hash_table, 4);
  74 static DEFINE_SPINLOCK(gss_auth_hash_lock);
  75
  76 struct gss_pipe {
  77         struct rpc_pipe_dir_object pdo;
  78         struct rpc_pipe *pipe;
  79         struct rpc_clnt *clnt;
  80         const char *name;
  81         struct kref kref;
  82 };
  83
  84 struct gss_auth {
  85         struct kref kref;
  86         struct hlist_node hash;
  87         struct rpc_auth rpc_auth;
  88         struct gss_api_mech *mech;
  89         enum rpc_gss_svc service;
  90         struct rpc_clnt *client;
  91         struct net      *net;
  92         netns_tracker   ns_tracker;
  93         /*
  94          * There are two upcall pipes; dentry[1], named "gssd", is used
  95          * for the new text-based upcall; dentry[0] is named after the
  96          * mechanism (for example, "krb5") and exists for
  97          * backwards-compatibility with older gssd's.
  98          */
  99         struct gss_pipe *gss_pipe[2];
 100         const char *target_name;
 101 };
 102
 103 /* pipe_version >= 0 if and only if someone has a pipe open. */
 104 static DEFINE_SPINLOCK(pipe_version_lock);
 105 static struct rpc_wait_queue pipe_version_rpc_waitqueue;
 106 static DECLARE_WAIT_QUEUE_HEAD(pipe_version_waitqueue);
 107 static void gss_put_auth(struct gss_auth *gss_auth);
 108
 109 static void gss_free_ctx(struct gss_cl_ctx *);
 110 static const struct rpc_pipe_ops gss_upcall_ops_v0;
 111 static const struct rpc_pipe_ops gss_upcall_ops_v1;
 112
 113 static inline struct gss_cl_ctx *
 114 gss_get_ctx(struct gss_cl_ctx *ctx)
 115 {
 116         refcount_inc(&ctx->count);
 117         return ctx;
 118 }
 119
 120 static inline void
 121 gss_put_ctx(struct gss_cl_ctx *ctx)
 122 {
 123         if (refcount_dec_and_test(&ctx->count))
 124                 gss_free_ctx(ctx);
 125 }
 126
 127 /* gss_cred_set_ctx:
 128  * called by gss_upcall_callback and gss_create_upcall in order
 129  * to set the gss context. The actual exchange of an old context
 130  * and a new one is protected by the pipe->lock.
 131  */
 132 static void
 133 gss_cred_set_ctx(struct rpc_cred *cred, struct gss_cl_ctx *ctx)
 134 {
 135         struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
 136
 137         if (!test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags))
 138                 return;
 139         gss_get_ctx(ctx);
 140         rcu_assign_pointer(gss_cred->gc_ctx, ctx);
 141         set_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
 142         smp_mb__before_atomic();
 143         clear_bit(RPCAUTH_CRED_NEW, &cred->cr_flags);
 144 }
 145
 146 static struct gss_cl_ctx *
 147 gss_cred_get_ctx(struct rpc_cred *cred)
 148 {
 149         struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
 150         struct gss_cl_ctx *ctx = NULL;
 151
 152         rcu_read_lock();
 153         ctx = rcu_dereference(gss_cred->gc_ctx);
 154         if (ctx)
 155                 gss_get_ctx(ctx);
 156         rcu_read_unlock();
 157         return ctx;
 158 }
 159
 160 static struct gss_cl_ctx *
 161 gss_alloc_context(void)
 162 {
 163         struct gss_cl_ctx *ctx;
 164
 165         ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
 166         if (ctx != NULL) {
 167                 ctx->gc_proc = RPC_GSS_PROC_DATA;
 168                 ctx->gc_seq = 1;        /* NetApp 6.4R1 doesn't accept seq. no. 0 */
 169                 spin_lock_init(&ctx->gc_seq_lock);
 170                 refcount_set(&ctx->count,1);
 171         }
 172         return ctx;
 173 }
 174
 175 #define GSSD_MIN_TIMEOUT (60 * 60)
 176 static const void *
 177 gss_fill_context(const void *p, const void *end, struct gss_cl_ctx *ctx, struct gss_api_mech *gm)
 178 {
 179         const void *q;
 180         unsigned int seclen;
 181         unsigned int timeout;
 182         unsigned long now = jiffies;
 183         u32 window_size;
 184         int ret;
 185
 186         /* First unsigned int gives the remaining lifetime in seconds of the
 187          * credential - e.g. the remaining TGT lifetime for Kerberos or
 188          * the -t value passed to GSSD.
 189          */
 190         p = simple_get_bytes(p, end, &timeout, sizeof(timeout));
 191         if (IS_ERR(p))
 192                 goto err;
 193         if (timeout == 0)
 194                 timeout = GSSD_MIN_TIMEOUT;
 195         ctx->gc_expiry = now + ((unsigned long)timeout * HZ);
 196         /* Sequence number window. Determines the maximum number of
 197          * simultaneous requests
 198          */
 199         p = simple_get_bytes(p, end, &window_size, sizeof(window_size));
 200         if (IS_ERR(p))
 201                 goto err;
 202         ctx->gc_win = window_size;
 203         /* gssd signals an error by passing ctx->gc_win = 0: */
 204         if (ctx->gc_win == 0) {
 205                 /*
 206                  * in which case, p points to an error code. Anything other
 207                  * than -EKEYEXPIRED gets converted to -EACCES.
 208                  */
 209                 p = simple_get_bytes(p, end, &ret, sizeof(ret));
 210                 if (!IS_ERR(p))
 211                         p = (ret == -EKEYEXPIRED) ? ERR_PTR(-EKEYEXPIRED) :
 212                                                     ERR_PTR(-EACCES);
 213                 goto err;
 214         }
 215         /* copy the opaque wire context */
 216         p = simple_get_netobj(p, end, &ctx->gc_wire_ctx);
 217         if (IS_ERR(p))
 218                 goto err;
 219         /* import the opaque security context */
 220         p  = simple_get_bytes(p, end, &seclen, sizeof(seclen));
 221         if (IS_ERR(p))
 222                 goto err;
 223         q = (const void *)((const char *)p + seclen);
 224         if (unlikely(q > end || q < p)) {
 225                 p = ERR_PTR(-EFAULT);
 226                 goto err;
 227         }
 228         ret = gss_import_sec_context(p, seclen, gm, &ctx->gc_gss_ctx, NULL, GFP_KERNEL);
 229         if (ret < 0) {
 230                 trace_rpcgss_import_ctx(ret);
 231                 p = ERR_PTR(ret);
 232                 goto err;
 233         }
 234
 235         /* is there any trailing data? */
 236         if (q == end) {
 237                 p = q;
 238                 goto done;
 239         }
 240
 241         /* pull in acceptor name (if there is one) */
 242         p = simple_get_netobj(q, end, &ctx->gc_acceptor);
 243         if (IS_ERR(p))
 244                 goto err;
 245 done:
 246         trace_rpcgss_context(window_size, ctx->gc_expiry, now, timeout,
 247                              ctx->gc_acceptor.len, ctx->gc_acceptor.data);
 248 err:
 249         return p;
 250 }
 251
 252 /* XXX: Need some documentation about why UPCALL_BUF_LEN is so small.
 253  *      Is user space expecting no more than UPCALL_BUF_LEN bytes?
 254  *      Note that there are now _two_ NI_MAXHOST sized data items
 255  *      being passed in this string.
 256  */
 257 #define UPCALL_BUF_LEN  256
 258
 259 struct gss_upcall_msg {
 260         refcount_t count;
 261         kuid_t  uid;
 262         const char *service_name;
 263         struct rpc_pipe_msg msg;
 264         struct list_head list;
 265         struct gss_auth *auth;
 266         struct rpc_pipe *pipe;
 267         struct rpc_wait_queue rpc_waitqueue;
 268         wait_queue_head_t waitqueue;
 269         struct gss_cl_ctx *ctx;
 270         char databuf[UPCALL_BUF_LEN];
 271 };
 272
 273 static int get_pipe_version(struct net *net)
 274 {
 275         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 276         int ret;
 277
 278         spin_lock(&pipe_version_lock);
 279         if (sn->pipe_version >= 0) {
 280                 atomic_inc(&sn->pipe_users);
 281                 ret = sn->pipe_version;
 282         } else
 283                 ret = -EAGAIN;
 284         spin_unlock(&pipe_version_lock);
 285         return ret;
 286 }
 287
 288 static void put_pipe_version(struct net *net)
 289 {
 290         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 291
 292         if (atomic_dec_and_lock(&sn->pipe_users, &pipe_version_lock)) {
 293                 sn->pipe_version = -1;
 294                 spin_unlock(&pipe_version_lock);
 295         }
 296 }
 297
 298 static void
 299 gss_release_msg(struct gss_upcall_msg *gss_msg)
 300 {
 301         struct net *net = gss_msg->auth->net;
 302         if (!refcount_dec_and_test(&gss_msg->count))
 303                 return;
 304         put_pipe_version(net);
 305         BUG_ON(!list_empty(&gss_msg->list));
 306         if (gss_msg->ctx != NULL)
 307                 gss_put_ctx(gss_msg->ctx);
 308         rpc_destroy_wait_queue(&gss_msg->rpc_waitqueue);
 309         gss_put_auth(gss_msg->auth);
 310         kfree_const(gss_msg->service_name);
 311         kfree(gss_msg);
 312 }
 313
 314 static struct gss_upcall_msg *
 315 __gss_find_upcall(struct rpc_pipe *pipe, kuid_t uid, const struct gss_auth *auth)
 316 {
 317         struct gss_upcall_msg *pos;
 318         list_for_each_entry(pos, &pipe->in_downcall, list) {
 319                 if (!uid_eq(pos->uid, uid))
 320                         continue;
 321                 if (pos->auth->service != auth->service)
 322                         continue;
 323                 refcount_inc(&pos->count);
 324                 return pos;
 325         }
 326         return NULL;
 327 }
 328
 329 /* Try to add an upcall to the pipefs queue.
 330  * If an upcall owned by our uid already exists, then we return a reference
 331  * to that upcall instead of adding the new upcall.
 332  */
 333 static inline struct gss_upcall_msg *
 334 gss_add_msg(struct gss_upcall_msg *gss_msg)
 335 {
 336         struct rpc_pipe *pipe = gss_msg->pipe;
 337         struct gss_upcall_msg *old;
 338
 339         spin_lock(&pipe->lock);
 340         old = __gss_find_upcall(pipe, gss_msg->uid, gss_msg->auth);
 341         if (old == NULL) {
 342                 refcount_inc(&gss_msg->count);
 343                 list_add(&gss_msg->list, &pipe->in_downcall);
 344         } else
 345                 gss_msg = old;
 346         spin_unlock(&pipe->lock);
 347         return gss_msg;
 348 }
 349
 350 static void
 351 __gss_unhash_msg(struct gss_upcall_msg *gss_msg)
 352 {
 353         list_del_init(&gss_msg->list);
 354         rpc_wake_up_status(&gss_msg->rpc_waitqueue, gss_msg->msg.errno);
 355         wake_up_all(&gss_msg->waitqueue);
 356         refcount_dec(&gss_msg->count);
 357 }
 358
 359 static void
 360 gss_unhash_msg(struct gss_upcall_msg *gss_msg)
 361 {
 362         struct rpc_pipe *pipe = gss_msg->pipe;
 363
 364         if (list_empty(&gss_msg->list))
 365                 return;
 366         spin_lock(&pipe->lock);
 367         if (!list_empty(&gss_msg->list))
 368                 __gss_unhash_msg(gss_msg);
 369         spin_unlock(&pipe->lock);
 370 }
 371
 372 static void
 373 gss_handle_downcall_result(struct gss_cred *gss_cred, struct gss_upcall_msg *gss_msg)
 374 {
 375         switch (gss_msg->msg.errno) {
 376         case 0:
 377                 if (gss_msg->ctx == NULL)
 378                         break;
 379                 clear_bit(RPCAUTH_CRED_NEGATIVE, &gss_cred->gc_base.cr_flags);
 380                 gss_cred_set_ctx(&gss_cred->gc_base, gss_msg->ctx);
 381                 break;
 382         case -EKEYEXPIRED:
 383                 set_bit(RPCAUTH_CRED_NEGATIVE, &gss_cred->gc_base.cr_flags);
 384         }
 385         gss_cred->gc_upcall_timestamp = jiffies;
 386         gss_cred->gc_upcall = NULL;
 387         rpc_wake_up_status(&gss_msg->rpc_waitqueue, gss_msg->msg.errno);
 388 }
 389
 390 static void
 391 gss_upcall_callback(struct rpc_task *task)
 392 {
 393         struct gss_cred *gss_cred = container_of(task->tk_rqstp->rq_cred,
 394                         struct gss_cred, gc_base);
 395         struct gss_upcall_msg *gss_msg = gss_cred->gc_upcall;
 396         struct rpc_pipe *pipe = gss_msg->pipe;
 397
 398         spin_lock(&pipe->lock);
 399         gss_handle_downcall_result(gss_cred, gss_msg);
 400         spin_unlock(&pipe->lock);
 401         task->tk_status = gss_msg->msg.errno;
 402         gss_release_msg(gss_msg);
 403 }
 404
 405 static void gss_encode_v0_msg(struct gss_upcall_msg *gss_msg,
 406                               const struct cred *cred)
 407 {
 408         struct user_namespace *userns = cred->user_ns;
 409
 410         uid_t uid = from_kuid_munged(userns, gss_msg->uid);
 411         memcpy(gss_msg->databuf, &uid, sizeof(uid));
 412         gss_msg->msg.data = gss_msg->databuf;
 413         gss_msg->msg.len = sizeof(uid);
 414
 415         BUILD_BUG_ON(sizeof(uid) > sizeof(gss_msg->databuf));
 416 }
 417
 418 static ssize_t
 419 gss_v0_upcall(struct file *file, struct rpc_pipe_msg *msg,
 420                 char __user *buf, size_t buflen)
 421 {
 422         struct gss_upcall_msg *gss_msg = container_of(msg,
 423                                                       struct gss_upcall_msg,
 424                                                       msg);
 425         if (msg->copied == 0)
 426                 gss_encode_v0_msg(gss_msg, file->f_cred);
 427         return rpc_pipe_generic_upcall(file, msg, buf, buflen);
 428 }
 429
 430 static int gss_encode_v1_msg(struct gss_upcall_msg *gss_msg,
 431                                 const char *service_name,
 432                                 const char *target_name,
 433                                 const struct cred *cred)
 434 {
 435         struct user_namespace *userns = cred->user_ns;
 436         struct gss_api_mech *mech = gss_msg->auth->mech;
 437         char *p = gss_msg->databuf;
 438         size_t buflen = sizeof(gss_msg->databuf);
 439         int len;
 440
 441         len = scnprintf(p, buflen, "mech=%s uid=%d", mech->gm_name,
 442                         from_kuid_munged(userns, gss_msg->uid));
 443         buflen -= len;
 444         p += len;
 445         gss_msg->msg.len = len;
 446
 447         /*
 448          * target= is a full service principal that names the remote
 449          * identity that we are authenticating to.
 450          */
 451         if (target_name) {
 452                 len = scnprintf(p, buflen, " target=%s", target_name);
 453                 buflen -= len;
 454                 p += len;
 455                 gss_msg->msg.len += len;
 456         }
 457
 458         /*
 459          * gssd uses service= and srchost= to select a matching key from
 460          * the system's keytab to use as the source principal.
 461          *
 462          * service= is the service name part of the source principal,
 463          * or "*" (meaning choose any).
 464          *
 465          * srchost= is the hostname part of the source principal. When
 466          * not provided, gssd uses the local hostname.
 467          */
 468         if (service_name) {
 469                 char *c = strchr(service_name, '@');
 470
 471                 if (!c)
 472                         len = scnprintf(p, buflen, " service=%s",
 473                                         service_name);
 474                 else
 475                         len = scnprintf(p, buflen,
 476                                         " service=%.*s srchost=%s",
 477                                         (int)(c - service_name),
 478                                         service_name, c + 1);
 479                 buflen -= len;
 480                 p += len;
 481                 gss_msg->msg.len += len;
 482         }
 483
 484         if (mech->gm_upcall_enctypes) {
 485                 len = scnprintf(p, buflen, " enctypes=%s",
 486                                 mech->gm_upcall_enctypes);
 487                 buflen -= len;
 488                 p += len;
 489                 gss_msg->msg.len += len;
 490         }
 491         trace_rpcgss_upcall_msg(gss_msg->databuf);
 492         len = scnprintf(p, buflen, "\n");
 493         if (len == 0)
 494                 goto out_overflow;
 495         gss_msg->msg.len += len;
 496         gss_msg->msg.data = gss_msg->databuf;
 497         return 0;
 498 out_overflow:
 499         WARN_ON_ONCE(1);
 500         return -ENOMEM;
 501 }
 502
 503 static ssize_t
 504 gss_v1_upcall(struct file *file, struct rpc_pipe_msg *msg,
 505                 char __user *buf, size_t buflen)
 506 {
 507         struct gss_upcall_msg *gss_msg = container_of(msg,
 508                                                       struct gss_upcall_msg,
 509                                                       msg);
 510         int err;
 511         if (msg->copied == 0) {
 512                 err = gss_encode_v1_msg(gss_msg,
 513                                         gss_msg->service_name,
 514                                         gss_msg->auth->target_name,
 515                                         file->f_cred);
 516                 if (err)
 517                         return err;
 518         }
 519         return rpc_pipe_generic_upcall(file, msg, buf, buflen);
 520 }
 521
 522 static struct gss_upcall_msg *
 523 gss_alloc_msg(struct gss_auth *gss_auth,
 524                 kuid_t uid, const char *service_name)
 525 {
 526         struct gss_upcall_msg *gss_msg;
 527         int vers;
 528         int err = -ENOMEM;
 529
 530         gss_msg = kzalloc(sizeof(*gss_msg), GFP_KERNEL);
 531         if (gss_msg == NULL)
 532                 goto err;
 533         vers = get_pipe_version(gss_auth->net);
 534         err = vers;
 535         if (err < 0)
 536                 goto err_free_msg;
 537         gss_msg->pipe = gss_auth->gss_pipe[vers]->pipe;
 538         INIT_LIST_HEAD(&gss_msg->list);
 539         rpc_init_wait_queue(&gss_msg->rpc_waitqueue, "RPCSEC_GSS upcall waitq");
 540         init_waitqueue_head(&gss_msg->waitqueue);
 541         refcount_set(&gss_msg->count, 1);
 542         gss_msg->uid = uid;
 543         gss_msg->auth = gss_auth;
 544         kref_get(&gss_auth->kref);
 545         if (service_name) {
 546                 gss_msg->service_name = kstrdup_const(service_name, GFP_KERNEL);
 547                 if (!gss_msg->service_name) {
 548                         err = -ENOMEM;
 549                         goto err_put_pipe_version;
 550                 }
 551         }
 552         return gss_msg;
 553 err_put_pipe_version:
 554         put_pipe_version(gss_auth->net);
 555 err_free_msg:
 556         kfree(gss_msg);
 557 err:
 558         return ERR_PTR(err);
 559 }
 560
 561 static struct gss_upcall_msg *
 562 gss_setup_upcall(struct gss_auth *gss_auth, struct rpc_cred *cred)
 563 {
 564         struct gss_cred *gss_cred = container_of(cred,
 565                         struct gss_cred, gc_base);
 566         struct gss_upcall_msg *gss_new, *gss_msg;
 567         kuid_t uid = cred->cr_cred->fsuid;
 568
 569         gss_new = gss_alloc_msg(gss_auth, uid, gss_cred->gc_principal);
 570         if (IS_ERR(gss_new))
 571                 return gss_new;
 572         gss_msg = gss_add_msg(gss_new);
 573         if (gss_msg == gss_new) {
 574                 int res;
 575                 refcount_inc(&gss_msg->count);
 576                 res = rpc_queue_upcall(gss_new->pipe, &gss_new->msg);
 577                 if (res) {
 578                         gss_unhash_msg(gss_new);
 579                         refcount_dec(&gss_msg->count);
 580                         gss_release_msg(gss_new);
 581                         gss_msg = ERR_PTR(res);
 582                 }
 583         } else
 584                 gss_release_msg(gss_new);
 585         return gss_msg;
 586 }
 587
 588 static void warn_gssd(void)
 589 {
 590         dprintk("AUTH_GSS upcall failed. Please check user daemon is running.\n");
 591 }
 592
 593 static inline int
 594 gss_refresh_upcall(struct rpc_task *task)
 595 {
 596         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 597         struct gss_auth *gss_auth = container_of(cred->cr_auth,
 598                         struct gss_auth, rpc_auth);
 599         struct gss_cred *gss_cred = container_of(cred,
 600                         struct gss_cred, gc_base);
 601         struct gss_upcall_msg *gss_msg;
 602         struct rpc_pipe *pipe;
 603         int err = 0;
 604
 605         gss_msg = gss_setup_upcall(gss_auth, cred);
 606         if (PTR_ERR(gss_msg) == -EAGAIN) {
 607                 /* XXX: warning on the first, under the assumption we
 608                  * shouldn't normally hit this case on a refresh. */
 609                 warn_gssd();
 610                 rpc_sleep_on_timeout(&pipe_version_rpc_waitqueue,
 611                                 task, NULL, jiffies + (15 * HZ));
 612                 err = -EAGAIN;
 613                 goto out;
 614         }
 615         if (IS_ERR(gss_msg)) {
 616                 err = PTR_ERR(gss_msg);
 617                 goto out;
 618         }
 619         pipe = gss_msg->pipe;
 620         spin_lock(&pipe->lock);
 621         if (gss_cred->gc_upcall != NULL)
 622                 rpc_sleep_on(&gss_cred->gc_upcall->rpc_waitqueue, task, NULL);
 623         else if (gss_msg->ctx == NULL && gss_msg->msg.errno >= 0) {
 624                 gss_cred->gc_upcall = gss_msg;
 625                 /* gss_upcall_callback will release the reference to gss_upcall_msg */
 626                 refcount_inc(&gss_msg->count);
 627                 rpc_sleep_on(&gss_msg->rpc_waitqueue, task, gss_upcall_callback);
 628         } else {
 629                 gss_handle_downcall_result(gss_cred, gss_msg);
 630                 err = gss_msg->msg.errno;
 631         }
 632         spin_unlock(&pipe->lock);
 633         gss_release_msg(gss_msg);
 634 out:
 635         trace_rpcgss_upcall_result(from_kuid(&init_user_ns,
 636                                              cred->cr_cred->fsuid), err);
 637         return err;
 638 }
 639
 640 static inline int
 641 gss_create_upcall(struct gss_auth *gss_auth, struct gss_cred *gss_cred)
 642 {
 643         struct net *net = gss_auth->net;
 644         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 645         struct rpc_pipe *pipe;
 646         struct rpc_cred *cred = &gss_cred->gc_base;
 647         struct gss_upcall_msg *gss_msg;
 648         DEFINE_WAIT(wait);
 649         int err;
 650
 651 retry:
 652         err = 0;
 653         /* if gssd is down, just skip upcalling altogether */
 654         if (!gssd_running(net)) {
 655                 warn_gssd();
 656                 err = -EACCES;
 657                 goto out;
 658         }
 659         gss_msg = gss_setup_upcall(gss_auth, cred);
 660         if (PTR_ERR(gss_msg) == -EAGAIN) {
 661                 err = wait_event_interruptible_timeout(pipe_version_waitqueue,
 662                                 sn->pipe_version >= 0, 15 * HZ);
 663                 if (sn->pipe_version < 0) {
 664                         warn_gssd();
 665                         err = -EACCES;
 666                 }
 667                 if (err < 0)
 668                         goto out;
 669                 goto retry;
 670         }
 671         if (IS_ERR(gss_msg)) {
 672                 err = PTR_ERR(gss_msg);
 673                 goto out;
 674         }
 675         pipe = gss_msg->pipe;
 676         for (;;) {
 677                 prepare_to_wait(&gss_msg->waitqueue, &wait, TASK_KILLABLE);
 678                 spin_lock(&pipe->lock);
 679                 if (gss_msg->ctx != NULL || gss_msg->msg.errno < 0) {
 680                         break;
 681                 }
 682                 spin_unlock(&pipe->lock);
 683                 if (fatal_signal_pending(current)) {
 684                         err = -ERESTARTSYS;
 685                         goto out_intr;
 686                 }
 687                 schedule();
 688         }
 689         if (gss_msg->ctx) {
 690                 trace_rpcgss_ctx_init(gss_cred);
 691                 gss_cred_set_ctx(cred, gss_msg->ctx);
 692         } else {
 693                 err = gss_msg->msg.errno;
 694         }
 695         spin_unlock(&pipe->lock);
 696 out_intr:
 697         finish_wait(&gss_msg->waitqueue, &wait);
 698         gss_release_msg(gss_msg);
 699 out:
 700         trace_rpcgss_upcall_result(from_kuid(&init_user_ns,
 701                                              cred->cr_cred->fsuid), err);
 702         return err;
 703 }
 704
 705 static struct gss_upcall_msg *
 706 gss_find_downcall(struct rpc_pipe *pipe, kuid_t uid)
 707 {
 708         struct gss_upcall_msg *pos;
 709         list_for_each_entry(pos, &pipe->in_downcall, list) {
 710                 if (!uid_eq(pos->uid, uid))
 711                         continue;
 712                 if (!rpc_msg_is_inflight(&pos->msg))
 713                         continue;
 714                 refcount_inc(&pos->count);
 715                 return pos;
 716         }
 717         return NULL;
 718 }
 719
 720 #define MSG_BUF_MAXSIZE 1024
 721
 722 static ssize_t
 723 gss_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 724 {
 725         const void *p, *end;
 726         void *buf;
 727         struct gss_upcall_msg *gss_msg;
 728         struct rpc_pipe *pipe = RPC_I(file_inode(filp))->pipe;
 729         struct gss_cl_ctx *ctx;
 730         uid_t id;
 731         kuid_t uid;
 732         ssize_t err = -EFBIG;
 733
 734         if (mlen > MSG_BUF_MAXSIZE)
 735                 goto out;
 736         err = -ENOMEM;
 737         buf = kmalloc(mlen, GFP_KERNEL);
 738         if (!buf)
 739                 goto out;
 740
 741         err = -EFAULT;
 742         if (copy_from_user(buf, src, mlen))
 743                 goto err;
 744
 745         end = (const void *)((char *)buf + mlen);
 746         p = simple_get_bytes(buf, end, &id, sizeof(id));
 747         if (IS_ERR(p)) {
 748                 err = PTR_ERR(p);
 749                 goto err;
 750         }
 751
 752         uid = make_kuid(current_user_ns(), id);
 753         if (!uid_valid(uid)) {
 754                 err = -EINVAL;
 755                 goto err;
 756         }
 757
 758         err = -ENOMEM;
 759         ctx = gss_alloc_context();
 760         if (ctx == NULL)
 761                 goto err;
 762
 763         err = -ENOENT;
 764         /* Find a matching upcall */
 765         spin_lock(&pipe->lock);
 766         gss_msg = gss_find_downcall(pipe, uid);
 767         if (gss_msg == NULL) {
 768                 spin_unlock(&pipe->lock);
 769                 goto err_put_ctx;
 770         }
 771         list_del_init(&gss_msg->list);
 772         spin_unlock(&pipe->lock);
 773
 774         p = gss_fill_context(p, end, ctx, gss_msg->auth->mech);
 775         if (IS_ERR(p)) {
 776                 err = PTR_ERR(p);
 777                 switch (err) {
 778                 case -EACCES:
 779                 case -EKEYEXPIRED:
 780                         gss_msg->msg.errno = err;
 781                         err = mlen;
 782                         break;
 783                 case -EFAULT:
 784                 case -ENOMEM:
 785                 case -EINVAL:
 786                 case -ENOSYS:
 787                         gss_msg->msg.errno = -EAGAIN;
 788                         break;
 789                 default:
 790                         printk(KERN_CRIT "%s: bad return from "
 791                                 "gss_fill_context: %zd\n", __func__, err);
 792                         gss_msg->msg.errno = -EIO;
 793                 }
 794                 goto err_release_msg;
 795         }
 796         gss_msg->ctx = gss_get_ctx(ctx);
 797         err = mlen;
 798
 799 err_release_msg:
 800         spin_lock(&pipe->lock);
 801         __gss_unhash_msg(gss_msg);
 802         spin_unlock(&pipe->lock);
 803         gss_release_msg(gss_msg);
 804 err_put_ctx:
 805         gss_put_ctx(ctx);
 806 err:
 807         kfree(buf);
 808 out:
 809         return err;
 810 }
 811
 812 static int gss_pipe_open(struct inode *inode, int new_version)
 813 {
 814         struct net *net = inode->i_sb->s_fs_info;
 815         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 816         int ret = 0;
 817
 818         spin_lock(&pipe_version_lock);
 819         if (sn->pipe_version < 0) {
 820                 /* First open of any gss pipe determines the version: */
 821                 sn->pipe_version = new_version;
 822                 rpc_wake_up(&pipe_version_rpc_waitqueue);
 823                 wake_up(&pipe_version_waitqueue);
 824         } else if (sn->pipe_version != new_version) {
 825                 /* Trying to open a pipe of a different version */
 826                 ret = -EBUSY;
 827                 goto out;
 828         }
 829         atomic_inc(&sn->pipe_users);
 830 out:
 831         spin_unlock(&pipe_version_lock);
 832         return ret;
 833
 834 }
 835
 836 static int gss_pipe_open_v0(struct inode *inode)
 837 {
 838         return gss_pipe_open(inode, 0);
 839 }
 840
 841 static int gss_pipe_open_v1(struct inode *inode)
 842 {
 843         return gss_pipe_open(inode, 1);
 844 }
 845
 846 static void
 847 gss_pipe_release(struct inode *inode)
 848 {
 849         struct net *net = inode->i_sb->s_fs_info;
 850         struct rpc_pipe *pipe = RPC_I(inode)->pipe;
 851         struct gss_upcall_msg *gss_msg;
 852
 853 restart:
 854         spin_lock(&pipe->lock);
 855         list_for_each_entry(gss_msg, &pipe->in_downcall, list) {
 856
 857                 if (!list_empty(&gss_msg->msg.list))
 858                         continue;
 859                 gss_msg->msg.errno = -EPIPE;
 860                 refcount_inc(&gss_msg->count);
 861                 __gss_unhash_msg(gss_msg);
 862                 spin_unlock(&pipe->lock);
 863                 gss_release_msg(gss_msg);
 864                 goto restart;
 865         }
 866         spin_unlock(&pipe->lock);
 867
 868         put_pipe_version(net);
 869 }
 870
 871 static void
 872 gss_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 873 {
 874         struct gss_upcall_msg *gss_msg = container_of(msg, struct gss_upcall_msg, msg);
 875
 876         if (msg->errno < 0) {
 877                 refcount_inc(&gss_msg->count);
 878                 gss_unhash_msg(gss_msg);
 879                 if (msg->errno == -ETIMEDOUT)
 880                         warn_gssd();
 881                 gss_release_msg(gss_msg);
 882         }
 883         gss_release_msg(gss_msg);
 884 }
 885
 886 static void gss_pipe_dentry_destroy(struct dentry *dir,
 887                 struct rpc_pipe_dir_object *pdo)
 888 {
 889         struct gss_pipe *gss_pipe = pdo->pdo_data;
 890         struct rpc_pipe *pipe = gss_pipe->pipe;
 891
 892         if (pipe->dentry != NULL) {
 893                 rpc_unlink(pipe->dentry);
 894                 pipe->dentry = NULL;
 895         }
 896 }
 897
 898 static int gss_pipe_dentry_create(struct dentry *dir,
 899                 struct rpc_pipe_dir_object *pdo)
 900 {
 901         struct gss_pipe *p = pdo->pdo_data;
 902         struct dentry *dentry;
 903
 904         dentry = rpc_mkpipe_dentry(dir, p->name, p->clnt, p->pipe);
 905         if (IS_ERR(dentry))
 906                 return PTR_ERR(dentry);
 907         p->pipe->dentry = dentry;
 908         return 0;
 909 }
 910
 911 static const struct rpc_pipe_dir_object_ops gss_pipe_dir_object_ops = {
 912         .create = gss_pipe_dentry_create,
 913         .destroy = gss_pipe_dentry_destroy,
 914 };
 915
 916 static struct gss_pipe *gss_pipe_alloc(struct rpc_clnt *clnt,
 917                 const char *name,
 918                 const struct rpc_pipe_ops *upcall_ops)
 919 {
 920         struct gss_pipe *p;
 921         int err = -ENOMEM;
 922
 923         p = kmalloc(sizeof(*p), GFP_KERNEL);
 924         if (p == NULL)
 925                 goto err;
 926         p->pipe = rpc_mkpipe_data(upcall_ops, RPC_PIPE_WAIT_FOR_OPEN);
 927         if (IS_ERR(p->pipe)) {
 928                 err = PTR_ERR(p->pipe);
 929                 goto err_free_gss_pipe;
 930         }
 931         p->name = name;
 932         p->clnt = clnt;
 933         kref_init(&p->kref);
 934         rpc_init_pipe_dir_object(&p->pdo,
 935                         &gss_pipe_dir_object_ops,
 936                         p);
 937         return p;
 938 err_free_gss_pipe:
 939         kfree(p);
 940 err:
 941         return ERR_PTR(err);
 942 }
 943
 944 struct gss_alloc_pdo {
 945         struct rpc_clnt *clnt;
 946         const char *name;
 947         const struct rpc_pipe_ops *upcall_ops;
 948 };
 949
 950 static int gss_pipe_match_pdo(struct rpc_pipe_dir_object *pdo, void *data)
 951 {
 952         struct gss_pipe *gss_pipe;
 953         struct gss_alloc_pdo *args = data;
 954
 955         if (pdo->pdo_ops != &gss_pipe_dir_object_ops)
 956                 return 0;
 957         gss_pipe = container_of(pdo, struct gss_pipe, pdo);
 958         if (strcmp(gss_pipe->name, args->name) != 0)
 959                 return 0;
 960         if (!kref_get_unless_zero(&gss_pipe->kref))
 961                 return 0;
 962         return 1;
 963 }
 964
 965 static struct rpc_pipe_dir_object *gss_pipe_alloc_pdo(void *data)
 966 {
 967         struct gss_pipe *gss_pipe;
 968         struct gss_alloc_pdo *args = data;
 969
 970         gss_pipe = gss_pipe_alloc(args->clnt, args->name, args->upcall_ops);
 971         if (!IS_ERR(gss_pipe))
 972                 return &gss_pipe->pdo;
 973         return NULL;
 974 }
 975
 976 static struct gss_pipe *gss_pipe_get(struct rpc_clnt *clnt,
 977                 const char *name,
 978                 const struct rpc_pipe_ops *upcall_ops)
 979 {
 980         struct net *net = rpc_net_ns(clnt);
 981         struct rpc_pipe_dir_object *pdo;
 982         struct gss_alloc_pdo args = {
 983                 .clnt = clnt,
 984                 .name = name,
 985                 .upcall_ops = upcall_ops,
 986         };
 987
 988         pdo = rpc_find_or_alloc_pipe_dir_object(net,
 989                         &clnt->cl_pipedir_objects,
 990                         gss_pipe_match_pdo,
 991                         gss_pipe_alloc_pdo,
 992                         &args);
 993         if (pdo != NULL)
 994                 return container_of(pdo, struct gss_pipe, pdo);
 995         return ERR_PTR(-ENOMEM);
 996 }
 997
 998 static void __gss_pipe_free(struct gss_pipe *p)
 999 {
1000         struct rpc_clnt *clnt = p->clnt;
1001         struct net *net = rpc_net_ns(clnt);
1002
1003         rpc_remove_pipe_dir_object(net,
1004                         &clnt->cl_pipedir_objects,
1005                         &p->pdo);
1006         rpc_destroy_pipe_data(p->pipe);
1007         kfree(p);
1008 }
1009
1010 static void __gss_pipe_release(struct kref *kref)
1011 {
1012         struct gss_pipe *p = container_of(kref, struct gss_pipe, kref);
1013
1014         __gss_pipe_free(p);
1015 }
1016
1017 static void gss_pipe_free(struct gss_pipe *p)
1018 {
1019         if (p != NULL)
1020                 kref_put(&p->kref, __gss_pipe_release);
1021 }
1022
1023 /*
1024  * NOTE: we have the opportunity to use different
1025  * parameters based on the input flavor (which must be a pseudoflavor)
1026  */
1027 static struct gss_auth *
1028 gss_create_new(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
1029 {
1030         rpc_authflavor_t flavor = args->pseudoflavor;
1031         struct gss_auth *gss_auth;
1032         struct gss_pipe *gss_pipe;
1033         struct rpc_auth * auth;
1034         int err = -ENOMEM; /* XXX? */
1035
1036         if (!try_module_get(THIS_MODULE))
1037                 return ERR_PTR(err);
1038         if (!(gss_auth = kmalloc(sizeof(*gss_auth), GFP_KERNEL)))
1039                 goto out_dec;
1040         INIT_HLIST_NODE(&gss_auth->hash);
1041         gss_auth->target_name = NULL;
1042         if (args->target_name) {
1043                 gss_auth->target_name = kstrdup(args->target_name, GFP_KERNEL);
1044                 if (gss_auth->target_name == NULL)
1045                         goto err_free;
1046         }
1047         gss_auth->client = clnt;
1048         gss_auth->net = get_net_track(rpc_net_ns(clnt), &gss_auth->ns_tracker,
1049                                       GFP_KERNEL);
1050         err = -EINVAL;
1051         gss_auth->mech = gss_mech_get_by_pseudoflavor(flavor);
1052         if (!gss_auth->mech)
1053                 goto err_put_net;
1054         gss_auth->service = gss_pseudoflavor_to_service(gss_auth->mech, flavor);
1055         if (gss_auth->service == 0)
1056                 goto err_put_mech;
1057         if (!gssd_running(gss_auth->net))
1058                 goto err_put_mech;
1059         auth = &gss_auth->rpc_auth;
1060         auth->au_cslack = GSS_CRED_SLACK >> 2;
1061         BUILD_BUG_ON(GSS_KRB5_MAX_SLACK_NEEDED > RPC_MAX_AUTH_SIZE);
1062         auth->au_rslack = GSS_KRB5_MAX_SLACK_NEEDED >> 2;
1063         auth->au_verfsize = GSS_VERF_SLACK >> 2;
1064         auth->au_ralign = GSS_VERF_SLACK >> 2;
1065         __set_bit(RPCAUTH_AUTH_UPDATE_SLACK, &auth->au_flags);
1066         auth->au_ops = &authgss_ops;
1067         auth->au_flavor = flavor;
1068         if (gss_pseudoflavor_to_datatouch(gss_auth->mech, flavor))
1069                 __set_bit(RPCAUTH_AUTH_DATATOUCH, &auth->au_flags);
1070         refcount_set(&auth->au_count, 1);
1071         kref_init(&gss_auth->kref);
1072
1073         err = rpcauth_init_credcache(auth);
1074         if (err)
1075                 goto err_put_mech;
1076         /*
1077          * Note: if we created the old pipe first, then someone who
1078          * examined the directory at the right moment might conclude
1079          * that we supported only the old pipe.  So we instead create
1080          * the new pipe first.
1081          */
1082         gss_pipe = gss_pipe_get(clnt, "gssd", &gss_upcall_ops_v1);
1083         if (IS_ERR(gss_pipe)) {
1084                 err = PTR_ERR(gss_pipe);
1085                 goto err_destroy_credcache;
1086         }
1087         gss_auth->gss_pipe[1] = gss_pipe;
1088
1089         gss_pipe = gss_pipe_get(clnt, gss_auth->mech->gm_name,
1090                         &gss_upcall_ops_v0);
1091         if (IS_ERR(gss_pipe)) {
1092                 err = PTR_ERR(gss_pipe);
1093                 goto err_destroy_pipe_1;
1094         }
1095         gss_auth->gss_pipe[0] = gss_pipe;
1096
1097         return gss_auth;
1098 err_destroy_pipe_1:
1099         gss_pipe_free(gss_auth->gss_pipe[1]);
1100 err_destroy_credcache:
1101         rpcauth_destroy_credcache(auth);
1102 err_put_mech:
1103         gss_mech_put(gss_auth->mech);
1104 err_put_net:
1105         put_net_track(gss_auth->net, &gss_auth->ns_tracker);
1106 err_free:
1107         kfree(gss_auth->target_name);
1108         kfree(gss_auth);
1109 out_dec:
1110         module_put(THIS_MODULE);
1111         trace_rpcgss_createauth(flavor, err);
1112         return ERR_PTR(err);
1113 }
1114
1115 static void
1116 gss_free(struct gss_auth *gss_auth)
1117 {
1118         gss_pipe_free(gss_auth->gss_pipe[0]);
1119         gss_pipe_free(gss_auth->gss_pipe[1]);
1120         gss_mech_put(gss_auth->mech);
1121         put_net_track(gss_auth->net, &gss_auth->ns_tracker);
1122         kfree(gss_auth->target_name);
1123
1124         kfree(gss_auth);
1125         module_put(THIS_MODULE);
1126 }
1127
1128 static void
1129 gss_free_callback(struct kref *kref)
1130 {
1131         struct gss_auth *gss_auth = container_of(kref, struct gss_auth, kref);
1132
1133         gss_free(gss_auth);
1134 }
1135
1136 static void
1137 gss_put_auth(struct gss_auth *gss_auth)
1138 {
1139         kref_put(&gss_auth->kref, gss_free_callback);
1140 }
1141
1142 static void
1143 gss_destroy(struct rpc_auth *auth)
1144 {
1145         struct gss_auth *gss_auth = container_of(auth,
1146                         struct gss_auth, rpc_auth);
1147
1148         if (hash_hashed(&gss_auth->hash)) {
1149                 spin_lock(&gss_auth_hash_lock);
1150                 hash_del(&gss_auth->hash);
1151                 spin_unlock(&gss_auth_hash_lock);
1152         }
1153
1154         gss_pipe_free(gss_auth->gss_pipe[0]);
1155         gss_auth->gss_pipe[0] = NULL;
1156         gss_pipe_free(gss_auth->gss_pipe[1]);
1157         gss_auth->gss_pipe[1] = NULL;
1158         rpcauth_destroy_credcache(auth);
1159
1160         gss_put_auth(gss_auth);
1161 }
1162
1163 /*
1164  * Auths may be shared between rpc clients that were cloned from a
1165  * common client with the same xprt, if they also share the flavor and
1166  * target_name.
1167  *
1168  * The auth is looked up from the oldest parent sharing the same
1169  * cl_xprt, and the auth itself references only that common parent
1170  * (which is guaranteed to last as long as any of its descendants).
1171  */
1172 static struct gss_auth *
1173 gss_auth_find_or_add_hashed(const struct rpc_auth_create_args *args,
1174                 struct rpc_clnt *clnt,
1175                 struct gss_auth *new)
1176 {
1177         struct gss_auth *gss_auth;
1178         unsigned long hashval = (unsigned long)clnt;
1179
1180         spin_lock(&gss_auth_hash_lock);
1181         hash_for_each_possible(gss_auth_hash_table,
1182                         gss_auth,
1183                         hash,
1184                         hashval) {
1185                 if (gss_auth->client != clnt)
1186                         continue;
1187                 if (gss_auth->rpc_auth.au_flavor != args->pseudoflavor)
1188                         continue;
1189                 if (gss_auth->target_name != args->target_name) {
1190                         if (gss_auth->target_name == NULL)
1191                                 continue;
1192                         if (args->target_name == NULL)
1193                                 continue;
1194                         if (strcmp(gss_auth->target_name, args->target_name))
1195                                 continue;
1196                 }
1197                 if (!refcount_inc_not_zero(&gss_auth->rpc_auth.au_count))
1198                         continue;
1199                 goto out;
1200         }
1201         if (new)
1202                 hash_add(gss_auth_hash_table, &new->hash, hashval);
1203         gss_auth = new;
1204 out:
1205         spin_unlock(&gss_auth_hash_lock);
1206         return gss_auth;
1207 }
1208
1209 static struct gss_auth *
1210 gss_create_hashed(const struct rpc_auth_create_args *args,
1211                   struct rpc_clnt *clnt)
1212 {
1213         struct gss_auth *gss_auth;
1214         struct gss_auth *new;
1215
1216         gss_auth = gss_auth_find_or_add_hashed(args, clnt, NULL);
1217         if (gss_auth != NULL)
1218                 goto out;
1219         new = gss_create_new(args, clnt);
1220         if (IS_ERR(new))
1221                 return new;
1222         gss_auth = gss_auth_find_or_add_hashed(args, clnt, new);
1223         if (gss_auth != new)
1224                 gss_destroy(&new->rpc_auth);
1225 out:
1226         return gss_auth;
1227 }
1228
1229 static struct rpc_auth *
1230 gss_create(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
1231 {
1232         struct gss_auth *gss_auth;
1233         struct rpc_xprt_switch *xps = rcu_access_pointer(clnt->cl_xpi.xpi_xpswitch);
1234
1235         while (clnt != clnt->cl_parent) {
1236                 struct rpc_clnt *parent = clnt->cl_parent;
1237                 /* Find the original parent for this transport */
1238                 if (rcu_access_pointer(parent->cl_xpi.xpi_xpswitch) != xps)
1239                         break;
1240                 clnt = parent;
1241         }
1242
1243         gss_auth = gss_create_hashed(args, clnt);
1244         if (IS_ERR(gss_auth))
1245                 return ERR_CAST(gss_auth);
1246         return &gss_auth->rpc_auth;
1247 }
1248
1249 static struct gss_cred *
1250 gss_dup_cred(struct gss_auth *gss_auth, struct gss_cred *gss_cred)
1251 {
1252         struct gss_cred *new;
1253
1254         /* Make a copy of the cred so that we can reference count it */
1255         new = kzalloc(sizeof(*gss_cred), GFP_KERNEL);
1256         if (new) {
1257                 struct auth_cred acred = {
1258                         .cred = gss_cred->gc_base.cr_cred,
1259                 };
1260                 struct gss_cl_ctx *ctx =
1261                         rcu_dereference_protected(gss_cred->gc_ctx, 1);
1262
1263                 rpcauth_init_cred(&new->gc_base, &acred,
1264                                 &gss_auth->rpc_auth,
1265                                 &gss_nullops);
1266                 new->gc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
1267                 new->gc_service = gss_cred->gc_service;
1268                 new->gc_principal = gss_cred->gc_principal;
1269                 kref_get(&gss_auth->kref);
1270                 rcu_assign_pointer(new->gc_ctx, ctx);
1271                 gss_get_ctx(ctx);
1272         }
1273         return new;
1274 }
1275
1276 /*
1277  * gss_send_destroy_context will cause the RPCSEC_GSS to send a NULL RPC call
1278  * to the server with the GSS control procedure field set to
1279  * RPC_GSS_PROC_DESTROY. This should normally cause the server to release
1280  * all RPCSEC_GSS state associated with that context.
1281  */
1282 static void
1283 gss_send_destroy_context(struct rpc_cred *cred)
1284 {
1285         struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
1286         struct gss_auth *gss_auth = container_of(cred->cr_auth, struct gss_auth, rpc_auth);
1287         struct gss_cl_ctx *ctx = rcu_dereference_protected(gss_cred->gc_ctx, 1);
1288         struct gss_cred *new;
1289         struct rpc_task *task;
1290
1291         new = gss_dup_cred(gss_auth, gss_cred);
1292         if (new) {
1293                 ctx->gc_proc = RPC_GSS_PROC_DESTROY;
1294
1295                 trace_rpcgss_ctx_destroy(gss_cred);
1296                 task = rpc_call_null(gss_auth->client, &new->gc_base,
1297                                      RPC_TASK_ASYNC);
1298                 if (!IS_ERR(task))
1299                         rpc_put_task(task);
1300
1301                 put_rpccred(&new->gc_base);
1302         }
1303 }
1304
1305 /* gss_destroy_cred (and gss_free_ctx) are used to clean up after failure
1306  * to create a new cred or context, so they check that things have been
1307  * allocated before freeing them. */
1308 static void
1309 gss_do_free_ctx(struct gss_cl_ctx *ctx)
1310 {
1311         gss_delete_sec_context(&ctx->gc_gss_ctx);
1312         kfree(ctx->gc_wire_ctx.data);
1313         kfree(ctx->gc_acceptor.data);
1314         kfree(ctx);
1315 }
1316
1317 static void
1318 gss_free_ctx_callback(struct rcu_head *head)
1319 {
1320         struct gss_cl_ctx *ctx = container_of(head, struct gss_cl_ctx, gc_rcu);
1321         gss_do_free_ctx(ctx);
1322 }
1323
1324 static void
1325 gss_free_ctx(struct gss_cl_ctx *ctx)
1326 {
1327         call_rcu(&ctx->gc_rcu, gss_free_ctx_callback);
1328 }
1329
1330 static void
1331 gss_free_cred(struct gss_cred *gss_cred)
1332 {
1333         kfree(gss_cred);
1334 }
1335
1336 static void
1337 gss_free_cred_callback(struct rcu_head *head)
1338 {
1339         struct gss_cred *gss_cred = container_of(head, struct gss_cred, gc_base.cr_rcu);
1340         gss_free_cred(gss_cred);
1341 }
1342
1343 static void
1344 gss_destroy_nullcred(struct rpc_cred *cred)
1345 {
1346         struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
1347         struct gss_auth *gss_auth = container_of(cred->cr_auth, struct gss_auth, rpc_auth);
1348         struct gss_cl_ctx *ctx = rcu_dereference_protected(gss_cred->gc_ctx, 1);
1349
1350         RCU_INIT_POINTER(gss_cred->gc_ctx, NULL);
1351         put_cred(cred->cr_cred);
1352         call_rcu(&cred->cr_rcu, gss_free_cred_callback);
1353         if (ctx)
1354                 gss_put_ctx(ctx);
1355         gss_put_auth(gss_auth);
1356 }
1357
1358 static void
1359 gss_destroy_cred(struct rpc_cred *cred)
1360 {
1361         if (test_and_clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0)
1362                 gss_send_destroy_context(cred);
1363         gss_destroy_nullcred(cred);
1364 }
1365
1366 static int
1367 gss_hash_cred(struct auth_cred *acred, unsigned int hashbits)
1368 {
1369         return hash_64(from_kuid(&init_user_ns, acred->cred->fsuid), hashbits);
1370 }
1371
1372 /*
1373  * Lookup RPCSEC_GSS cred for the current process
1374  */
1375 static struct rpc_cred *gss_lookup_cred(struct rpc_auth *auth,
1376                                         struct auth_cred *acred, int flags)
1377 {
1378         return rpcauth_lookup_credcache(auth, acred, flags,
1379                                         rpc_task_gfp_mask());
1380 }
1381
1382 static struct rpc_cred *
1383 gss_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags, gfp_t gfp)
1384 {
1385         struct gss_auth *gss_auth = container_of(auth, struct gss_auth, rpc_auth);
1386         struct gss_cred *cred = NULL;
1387         int err = -ENOMEM;
1388
1389         if (!(cred = kzalloc(sizeof(*cred), gfp)))
1390                 goto out_err;
1391
1392         rpcauth_init_cred(&cred->gc_base, acred, auth, &gss_credops);
1393         /*
1394          * Note: in order to force a call to call_refresh(), we deliberately
1395          * fail to flag the credential as RPCAUTH_CRED_UPTODATE.
1396          */
1397         cred->gc_base.cr_flags = 1UL << RPCAUTH_CRED_NEW;
1398         cred->gc_service = gss_auth->service;
1399         cred->gc_principal = acred->principal;
1400         kref_get(&gss_auth->kref);
1401         return &cred->gc_base;
1402
1403 out_err:
1404         return ERR_PTR(err);
1405 }
1406
1407 static int
1408 gss_cred_init(struct rpc_auth *auth, struct rpc_cred *cred)
1409 {
1410         struct gss_auth *gss_auth = container_of(auth, struct gss_auth, rpc_auth);
1411         struct gss_cred *gss_cred = container_of(cred,struct gss_cred, gc_base);
1412         int err;
1413
1414         do {
1415                 err = gss_create_upcall(gss_auth, gss_cred);
1416         } while (err == -EAGAIN);
1417         return err;
1418 }
1419
1420 static char *
1421 gss_stringify_acceptor(struct rpc_cred *cred)
1422 {
1423         char *string = NULL;
1424         struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
1425         struct gss_cl_ctx *ctx;
1426         unsigned int len;
1427         struct xdr_netobj *acceptor;
1428
1429         rcu_read_lock();
1430         ctx = rcu_dereference(gss_cred->gc_ctx);
1431         if (!ctx)
1432                 goto out;
1433
1434         len = ctx->gc_acceptor.len;
1435         rcu_read_unlock();
1436
1437         /* no point if there's no string */
1438         if (!len)
1439                 return NULL;
1440 realloc:
1441         string = kmalloc(len + 1, GFP_KERNEL);
1442         if (!string)
1443                 return NULL;
1444
1445         rcu_read_lock();
1446         ctx = rcu_dereference(gss_cred->gc_ctx);
1447
1448         /* did the ctx disappear or was it replaced by one with no acceptor? */
1449         if (!ctx || !ctx->gc_acceptor.len) {
1450                 kfree(string);
1451                 string = NULL;
1452                 goto out;
1453         }
1454
1455         acceptor = &ctx->gc_acceptor;
1456
1457         /*
1458          * Did we find a new acceptor that's longer than the original? Allocate
1459          * a longer buffer and try again.
1460          */
1461         if (len < acceptor->len) {
1462                 len = acceptor->len;
1463                 rcu_read_unlock();
1464                 kfree(string);
1465                 goto realloc;
1466         }
1467
1468         memcpy(string, acceptor->data, acceptor->len);
1469         string[acceptor->len] = '\0';
1470 out:
1471         rcu_read_unlock();
1472         return string;
1473 }
1474
1475 /*
1476  * Returns -EACCES if GSS context is NULL or will expire within the
1477  * timeout (miliseconds)
1478  */
1479 static int
1480 gss_key_timeout(struct rpc_cred *rc)
1481 {
1482         struct gss_cred *gss_cred = container_of(rc, struct gss_cred, gc_base);
1483         struct gss_cl_ctx *ctx;
1484         unsigned long timeout = jiffies + (gss_key_expire_timeo * HZ);
1485         int ret = 0;
1486
1487         rcu_read_lock();
1488         ctx = rcu_dereference(gss_cred->gc_ctx);
1489         if (!ctx || time_after(timeout, ctx->gc_expiry))
1490                 ret = -EACCES;
1491         rcu_read_unlock();
1492
1493         return ret;
1494 }
1495
1496 static int
1497 gss_match(struct auth_cred *acred, struct rpc_cred *rc, int flags)
1498 {
1499         struct gss_cred *gss_cred = container_of(rc, struct gss_cred, gc_base);
1500         struct gss_cl_ctx *ctx;
1501         int ret;
1502
1503         if (test_bit(RPCAUTH_CRED_NEW, &rc->cr_flags))
1504                 goto out;
1505         /* Don't match with creds that have expired. */
1506         rcu_read_lock();
1507         ctx = rcu_dereference(gss_cred->gc_ctx);
1508         if (!ctx || time_after(jiffies, ctx->gc_expiry)) {
1509                 rcu_read_unlock();
1510                 return 0;
1511         }
1512         rcu_read_unlock();
1513         if (!test_bit(RPCAUTH_CRED_UPTODATE, &rc->cr_flags))
1514                 return 0;
1515 out:
1516         if (acred->principal != NULL) {
1517                 if (gss_cred->gc_principal == NULL)
1518                         return 0;
1519                 ret = strcmp(acred->principal, gss_cred->gc_principal) == 0;
1520         } else {
1521                 if (gss_cred->gc_principal != NULL)
1522                         return 0;
1523                 ret = uid_eq(rc->cr_cred->fsuid, acred->cred->fsuid);
1524         }
1525         return ret;
1526 }
1527
1528 /*
1529  * Marshal credentials.
1530  *
1531  * The expensive part is computing the verifier. We can't cache a
1532  * pre-computed version of the verifier because the seqno, which
1533  * is different every time, is included in the MIC.
1534  */
1535 static int gss_marshal(struct rpc_task *task, struct xdr_stream *xdr)
1536 {
1537         struct rpc_rqst *req = task->tk_rqstp;
1538         struct rpc_cred *cred = req->rq_cred;
1539         struct gss_cred *gss_cred = container_of(cred, struct gss_cred,
1540                                                  gc_base);
1541         struct gss_cl_ctx       *ctx = gss_cred_get_ctx(cred);
1542         __be32          *p, *cred_len;
1543         u32             maj_stat = 0;
1544         struct xdr_netobj mic;
1545         struct kvec     iov;
1546         struct xdr_buf  verf_buf;
1547         int status;
1548
1549         /* Credential */
1550
1551         p = xdr_reserve_space(xdr, 7 * sizeof(*p) +
1552                               ctx->gc_wire_ctx.len);
1553         if (!p)
1554                 goto marshal_failed;
1555         *p++ = rpc_auth_gss;
1556         cred_len = p++;
1557
1558         spin_lock(&ctx->gc_seq_lock);
1559         req->rq_seqno = (ctx->gc_seq < MAXSEQ) ? ctx->gc_seq++ : MAXSEQ;
1560         spin_unlock(&ctx->gc_seq_lock);
1561         if (req->rq_seqno == MAXSEQ)
1562                 goto expired;
1563         trace_rpcgss_seqno(task);
1564
1565         *p++ = cpu_to_be32(RPC_GSS_VERSION);
1566         *p++ = cpu_to_be32(ctx->gc_proc);
1567         *p++ = cpu_to_be32(req->rq_seqno);
1568         *p++ = cpu_to_be32(gss_cred->gc_service);
1569         p = xdr_encode_netobj(p, &ctx->gc_wire_ctx);
1570         *cred_len = cpu_to_be32((p - (cred_len + 1)) << 2);
1571
1572         /* Verifier */
1573
1574         /* We compute the checksum for the verifier over the xdr-encoded bytes
1575          * starting with the xid and ending at the end of the credential: */
1576         iov.iov_base = req->rq_snd_buf.head[0].iov_base;
1577         iov.iov_len = (u8 *)p - (u8 *)iov.iov_base;
1578         xdr_buf_from_iov(&iov, &verf_buf);
1579
1580         p = xdr_reserve_space(xdr, sizeof(*p));
1581         if (!p)
1582                 goto marshal_failed;
1583         *p++ = rpc_auth_gss;
1584         mic.data = (u8 *)(p + 1);
1585         maj_stat = gss_get_mic(ctx->gc_gss_ctx, &verf_buf, &mic);
1586         if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1587                 goto expired;
1588         else if (maj_stat != 0)
1589                 goto bad_mic;
1590         if (xdr_stream_encode_opaque_inline(xdr, (void **)&p, mic.len) < 0)
1591                 goto marshal_failed;
1592         status = 0;
1593 out:
1594         gss_put_ctx(ctx);
1595         return status;
1596 expired:
1597         clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1598         status = -EKEYEXPIRED;
1599         goto out;
1600 marshal_failed:
1601         status = -EMSGSIZE;
1602         goto out;
1603 bad_mic:
1604         trace_rpcgss_get_mic(task, maj_stat);
1605         status = -EIO;
1606         goto out;
1607 }
1608
1609 static int gss_renew_cred(struct rpc_task *task)
1610 {
1611         struct rpc_cred *oldcred = task->tk_rqstp->rq_cred;
1612         struct gss_cred *gss_cred = container_of(oldcred,
1613                                                  struct gss_cred,
1614                                                  gc_base);
1615         struct rpc_auth *auth = oldcred->cr_auth;
1616         struct auth_cred acred = {
1617                 .cred = oldcred->cr_cred,
1618                 .principal = gss_cred->gc_principal,
1619         };
1620         struct rpc_cred *new;
1621
1622         new = gss_lookup_cred(auth, &acred, RPCAUTH_LOOKUP_NEW);
1623         if (IS_ERR(new))
1624                 return PTR_ERR(new);
1625
1626         task->tk_rqstp->rq_cred = new;
1627         put_rpccred(oldcred);
1628         return 0;
1629 }
1630
1631 static int gss_cred_is_negative_entry(struct rpc_cred *cred)
1632 {
1633         if (test_bit(RPCAUTH_CRED_NEGATIVE, &cred->cr_flags)) {
1634                 unsigned long now = jiffies;
1635                 unsigned long begin, expire;
1636                 struct gss_cred *gss_cred;
1637
1638                 gss_cred = container_of(cred, struct gss_cred, gc_base);
1639                 begin = gss_cred->gc_upcall_timestamp;
1640                 expire = begin + gss_expired_cred_retry_delay * HZ;
1641
1642                 if (time_in_range_open(now, begin, expire))
1643                         return 1;
1644         }
1645         return 0;
1646 }
1647
1648 /*
1649 * Refresh credentials. XXX - finish
1650 */
1651 static int
1652 gss_refresh(struct rpc_task *task)
1653 {
1654         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
1655         int ret = 0;
1656
1657         if (gss_cred_is_negative_entry(cred))
1658                 return -EKEYEXPIRED;
1659
1660         if (!test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags) &&
1661                         !test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags)) {
1662                 ret = gss_renew_cred(task);
1663                 if (ret < 0)
1664                         goto out;
1665                 cred = task->tk_rqstp->rq_cred;
1666         }
1667
1668         if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags))
1669                 ret = gss_refresh_upcall(task);
1670 out:
1671         return ret;
1672 }
1673
1674 /* Dummy refresh routine: used only when destroying the context */
1675 static int
1676 gss_refresh_null(struct rpc_task *task)
1677 {
1678         return 0;
1679 }
1680
1681 static int
1682 gss_validate(struct rpc_task *task, struct xdr_stream *xdr)
1683 {
1684         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
1685         struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
1686         __be32          *p, *seq = NULL;
1687         struct kvec     iov;
1688         struct xdr_buf  verf_buf;
1689         struct xdr_netobj mic;
1690         u32             len, maj_stat;
1691         int             status;
1692
1693         p = xdr_inline_decode(xdr, 2 * sizeof(*p));
1694         if (!p)
1695                 goto validate_failed;
1696         if (*p++ != rpc_auth_gss)
1697                 goto validate_failed;
1698         len = be32_to_cpup(p);
1699         if (len > RPC_MAX_AUTH_SIZE)
1700                 goto validate_failed;
1701         p = xdr_inline_decode(xdr, len);
1702         if (!p)
1703                 goto validate_failed;
1704
1705         seq = kmalloc(4, GFP_KERNEL);
1706         if (!seq)
1707                 goto validate_failed;
1708         *seq = cpu_to_be32(task->tk_rqstp->rq_seqno);
1709         iov.iov_base = seq;
1710         iov.iov_len = 4;
1711         xdr_buf_from_iov(&iov, &verf_buf);
1712         mic.data = (u8 *)p;
1713         mic.len = len;
1714         maj_stat = gss_verify_mic(ctx->gc_gss_ctx, &verf_buf, &mic);
1715         if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1716                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1717         if (maj_stat)
1718                 goto bad_mic;
1719
1720         /* We leave it to unwrap to calculate au_rslack. For now we just
1721          * calculate the length of the verifier: */
1722         if (test_bit(RPCAUTH_AUTH_UPDATE_SLACK, &cred->cr_auth->au_flags))
1723                 cred->cr_auth->au_verfsize = XDR_QUADLEN(len) + 2;
1724         status = 0;
1725 out:
1726         gss_put_ctx(ctx);
1727         kfree(seq);
1728         return status;
1729
1730 validate_failed:
1731         status = -EIO;
1732         goto out;
1733 bad_mic:
1734         trace_rpcgss_verify_mic(task, maj_stat);
1735         status = -EACCES;
1736         goto out;
1737 }
1738
1739 static noinline_for_stack int
1740 gss_wrap_req_integ(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
1741                    struct rpc_task *task, struct xdr_stream *xdr)
1742 {
1743         struct rpc_rqst *rqstp = task->tk_rqstp;
1744         struct xdr_buf integ_buf, *snd_buf = &rqstp->rq_snd_buf;
1745         struct xdr_netobj mic;
1746         __be32 *p, *integ_len;
1747         u32 offset, maj_stat;
1748
1749         p = xdr_reserve_space(xdr, 2 * sizeof(*p));
1750         if (!p)
1751                 goto wrap_failed;
1752         integ_len = p++;
1753         *p = cpu_to_be32(rqstp->rq_seqno);
1754
1755         if (rpcauth_wrap_req_encode(task, xdr))
1756                 goto wrap_failed;
1757
1758         offset = (u8 *)p - (u8 *)snd_buf->head[0].iov_base;
1759         if (xdr_buf_subsegment(snd_buf, &integ_buf,
1760                                 offset, snd_buf->len - offset))
1761                 goto wrap_failed;
1762         *integ_len = cpu_to_be32(integ_buf.len);
1763
1764         p = xdr_reserve_space(xdr, 0);
1765         if (!p)
1766                 goto wrap_failed;
1767         mic.data = (u8 *)(p + 1);
1768         maj_stat = gss_get_mic(ctx->gc_gss_ctx, &integ_buf, &mic);
1769         if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1770                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1771         else if (maj_stat)
1772                 goto bad_mic;
1773         /* Check that the trailing MIC fit in the buffer, after the fact */
1774         if (xdr_stream_encode_opaque_inline(xdr, (void **)&p, mic.len) < 0)
1775                 goto wrap_failed;
1776         return 0;
1777 wrap_failed:
1778         return -EMSGSIZE;
1779 bad_mic:
1780         trace_rpcgss_get_mic(task, maj_stat);
1781         return -EIO;
1782 }
1783
1784 static void
1785 priv_release_snd_buf(struct rpc_rqst *rqstp)
1786 {
1787         int i;
1788
1789         for (i=0; i < rqstp->rq_enc_pages_num; i++)
1790                 __free_page(rqstp->rq_enc_pages[i]);
1791         kfree(rqstp->rq_enc_pages);
1792         rqstp->rq_release_snd_buf = NULL;
1793 }
1794
1795 static int
1796 alloc_enc_pages(struct rpc_rqst *rqstp)
1797 {
1798         struct xdr_buf *snd_buf = &rqstp->rq_snd_buf;
1799         int first, last, i;
1800
1801         if (rqstp->rq_release_snd_buf)
1802                 rqstp->rq_release_snd_buf(rqstp);
1803
1804         if (snd_buf->page_len == 0) {
1805                 rqstp->rq_enc_pages_num = 0;
1806                 return 0;
1807         }
1808
1809         first = snd_buf->page_base >> PAGE_SHIFT;
1810         last = (snd_buf->page_base + snd_buf->page_len - 1) >> PAGE_SHIFT;
1811         rqstp->rq_enc_pages_num = last - first + 1 + 1;
1812         rqstp->rq_enc_pages
1813                 = kmalloc_array(rqstp->rq_enc_pages_num,
1814                                 sizeof(struct page *),
1815                                 GFP_KERNEL);
1816         if (!rqstp->rq_enc_pages)
1817                 goto out;
1818         for (i=0; i < rqstp->rq_enc_pages_num; i++) {
1819                 rqstp->rq_enc_pages[i] = alloc_page(GFP_KERNEL);
1820                 if (rqstp->rq_enc_pages[i] == NULL)
1821                         goto out_free;
1822         }
1823         rqstp->rq_release_snd_buf = priv_release_snd_buf;
1824         return 0;
1825 out_free:
1826         rqstp->rq_enc_pages_num = i;
1827         priv_release_snd_buf(rqstp);
1828 out:
1829         return -EAGAIN;
1830 }
1831
1832 static noinline_for_stack int
1833 gss_wrap_req_priv(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
1834                   struct rpc_task *task, struct xdr_stream *xdr)
1835 {
1836         struct rpc_rqst *rqstp = task->tk_rqstp;
1837         struct xdr_buf  *snd_buf = &rqstp->rq_snd_buf;
1838         u32             pad, offset, maj_stat;
1839         int             status;
1840         __be32          *p, *opaque_len;
1841         struct page     **inpages;
1842         int             first;
1843         struct kvec     *iov;
1844
1845         status = -EIO;
1846         p = xdr_reserve_space(xdr, 2 * sizeof(*p));
1847         if (!p)
1848                 goto wrap_failed;
1849         opaque_len = p++;
1850         *p = cpu_to_be32(rqstp->rq_seqno);
1851
1852         if (rpcauth_wrap_req_encode(task, xdr))
1853                 goto wrap_failed;
1854
1855         status = alloc_enc_pages(rqstp);
1856         if (unlikely(status))
1857                 goto wrap_failed;
1858         first = snd_buf->page_base >> PAGE_SHIFT;
1859         inpages = snd_buf->pages + first;
1860         snd_buf->pages = rqstp->rq_enc_pages;
1861         snd_buf->page_base -= first << PAGE_SHIFT;
1862         /*
1863          * Move the tail into its own page, in case gss_wrap needs
1864          * more space in the head when wrapping.
1865          *
1866          * Still... Why can't gss_wrap just slide the tail down?
1867          */
1868         if (snd_buf->page_len || snd_buf->tail[0].iov_len) {
1869                 char *tmp;
1870
1871                 tmp = page_address(rqstp->rq_enc_pages[rqstp->rq_enc_pages_num - 1]);
1872                 memcpy(tmp, snd_buf->tail[0].iov_base, snd_buf->tail[0].iov_len);
1873                 snd_buf->tail[0].iov_base = tmp;
1874         }
1875         offset = (u8 *)p - (u8 *)snd_buf->head[0].iov_base;
1876         maj_stat = gss_wrap(ctx->gc_gss_ctx, offset, snd_buf, inpages);
1877         /* slack space should prevent this ever happening: */
1878         if (unlikely(snd_buf->len > snd_buf->buflen))
1879                 goto wrap_failed;
1880         /* We're assuming that when GSS_S_CONTEXT_EXPIRED, the encryption was
1881          * done anyway, so it's safe to put the request on the wire: */
1882         if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1883                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1884         else if (maj_stat)
1885                 goto bad_wrap;
1886
1887         *opaque_len = cpu_to_be32(snd_buf->len - offset);
1888         /* guess whether the pad goes into the head or the tail: */
1889         if (snd_buf->page_len || snd_buf->tail[0].iov_len)
1890                 iov = snd_buf->tail;
1891         else
1892                 iov = snd_buf->head;
1893         p = iov->iov_base + iov->iov_len;
1894         pad = xdr_pad_size(snd_buf->len - offset);
1895         memset(p, 0, pad);
1896         iov->iov_len += pad;
1897         snd_buf->len += pad;
1898
1899         return 0;
1900 wrap_failed:
1901         return status;
1902 bad_wrap:
1903         trace_rpcgss_wrap(task, maj_stat);
1904         return -EIO;
1905 }
1906
1907 static int gss_wrap_req(struct rpc_task *task, struct xdr_stream *xdr)
1908 {
1909         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
1910         struct gss_cred *gss_cred = container_of(cred, struct gss_cred,
1911                         gc_base);
1912         struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
1913         int status;
1914
1915         status = -EIO;
1916         if (ctx->gc_proc != RPC_GSS_PROC_DATA) {
1917                 /* The spec seems a little ambiguous here, but I think that not
1918                  * wrapping context destruction requests makes the most sense.
1919                  */
1920                 status = rpcauth_wrap_req_encode(task, xdr);
1921                 goto out;
1922         }
1923         switch (gss_cred->gc_service) {
1924         case RPC_GSS_SVC_NONE:
1925                 status = rpcauth_wrap_req_encode(task, xdr);
1926                 break;
1927         case RPC_GSS_SVC_INTEGRITY:
1928                 status = gss_wrap_req_integ(cred, ctx, task, xdr);
1929                 break;
1930         case RPC_GSS_SVC_PRIVACY:
1931                 status = gss_wrap_req_priv(cred, ctx, task, xdr);
1932                 break;
1933         default:
1934                 status = -EIO;
1935         }
1936 out:
1937         gss_put_ctx(ctx);
1938         return status;
1939 }
1940
1941 /**
1942  * gss_update_rslack - Possibly update RPC receive buffer size estimates
1943  * @task: rpc_task for incoming RPC Reply being unwrapped
1944  * @cred: controlling rpc_cred for @task
1945  * @before: XDR words needed before each RPC Reply message
1946  * @after: XDR words needed following each RPC Reply message
1947  *
1948  */
1949 static void gss_update_rslack(struct rpc_task *task, struct rpc_cred *cred,
1950                               unsigned int before, unsigned int after)
1951 {
1952         struct rpc_auth *auth = cred->cr_auth;
1953
1954         if (test_and_clear_bit(RPCAUTH_AUTH_UPDATE_SLACK, &auth->au_flags)) {
1955                 auth->au_ralign = auth->au_verfsize + before;
1956                 auth->au_rslack = auth->au_verfsize + after;
1957                 trace_rpcgss_update_slack(task, auth);
1958         }
1959 }
1960
1961 static int
1962 gss_unwrap_resp_auth(struct rpc_task *task, struct rpc_cred *cred)
1963 {
1964         gss_update_rslack(task, cred, 0, 0);
1965         return 0;
1966 }
1967
1968 /*
1969  * RFC 2203, Section 5.3.2.2
1970  *
1971  *      struct rpc_gss_integ_data {
1972  *              opaque databody_integ<>;
1973  *              opaque checksum<>;
1974  *      };
1975  *
1976  *      struct rpc_gss_data_t {
1977  *              unsigned int seq_num;
1978  *              proc_req_arg_t arg;
1979  *      };
1980  */
1981 static noinline_for_stack int
1982 gss_unwrap_resp_integ(struct rpc_task *task, struct rpc_cred *cred,
1983                       struct gss_cl_ctx *ctx, struct rpc_rqst *rqstp,
1984                       struct xdr_stream *xdr)
1985 {
1986         struct xdr_buf gss_data, *rcv_buf = &rqstp->rq_rcv_buf;
1987         u32 len, offset, seqno, maj_stat;
1988         struct xdr_netobj mic;
1989         int ret;
1990
1991         ret = -EIO;
1992         mic.data = NULL;
1993
1994         /* opaque databody_integ<>; */
1995         if (xdr_stream_decode_u32(xdr, &len))
1996                 goto unwrap_failed;
1997         if (len & 3)
1998                 goto unwrap_failed;
1999         offset = rcv_buf->len - xdr_stream_remaining(xdr);
2000         if (xdr_stream_decode_u32(xdr, &seqno))
2001                 goto unwrap_failed;
2002         if (seqno != rqstp->rq_seqno)
2003                 goto bad_seqno;
2004         if (xdr_buf_subsegment(rcv_buf, &gss_data, offset, len))
2005                 goto unwrap_failed;
2006
2007         /*
2008          * The xdr_stream now points to the beginning of the
2009          * upper layer payload, to be passed below to
2010          * rpcauth_unwrap_resp_decode(). The checksum, which
2011          * follows the upper layer payload in @rcv_buf, is
2012          * located and parsed without updating the xdr_stream.
2013          */
2014
2015         /* opaque checksum<>; */
2016         offset += len;
2017         if (xdr_decode_word(rcv_buf, offset, &len))
2018                 goto unwrap_failed;
2019         offset += sizeof(__be32);
2020         if (offset + len > rcv_buf->len)
2021                 goto unwrap_failed;
2022         mic.len = len;
2023         mic.data = kmalloc(len, GFP_KERNEL);
2024         if (ZERO_OR_NULL_PTR(mic.data))
2025                 goto unwrap_failed;
2026         if (read_bytes_from_xdr_buf(rcv_buf, offset, mic.data, mic.len))
2027                 goto unwrap_failed;
2028
2029         maj_stat = gss_verify_mic(ctx->gc_gss_ctx, &gss_data, &mic);
2030         if (maj_stat == GSS_S_CONTEXT_EXPIRED)
2031                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
2032         if (maj_stat != GSS_S_COMPLETE)
2033                 goto bad_mic;
2034
2035         gss_update_rslack(task, cred, 2, 2 + 1 + XDR_QUADLEN(mic.len));
2036         ret = 0;
2037
2038 out:
2039         kfree(mic.data);
2040         return ret;
2041
2042 unwrap_failed:
2043         trace_rpcgss_unwrap_failed(task);
2044         goto out;
2045 bad_seqno:
2046         trace_rpcgss_bad_seqno(task, rqstp->rq_seqno, seqno);
2047         goto out;
2048 bad_mic:
2049         trace_rpcgss_verify_mic(task, maj_stat);
2050         goto out;
2051 }
2052
2053 static noinline_for_stack int
2054 gss_unwrap_resp_priv(struct rpc_task *task, struct rpc_cred *cred,
2055                      struct gss_cl_ctx *ctx, struct rpc_rqst *rqstp,
2056                      struct xdr_stream *xdr)
2057 {
2058         struct xdr_buf *rcv_buf = &rqstp->rq_rcv_buf;
2059         struct kvec *head = rqstp->rq_rcv_buf.head;
2060         u32 offset, opaque_len, maj_stat;
2061         __be32 *p;
2062
2063         p = xdr_inline_decode(xdr, 2 * sizeof(*p));
2064         if (unlikely(!p))
2065                 goto unwrap_failed;
2066         opaque_len = be32_to_cpup(p++);
2067         offset = (u8 *)(p) - (u8 *)head->iov_base;
2068         if (offset + opaque_len > rcv_buf->len)
2069                 goto unwrap_failed;
2070
2071         maj_stat = gss_unwrap(ctx->gc_gss_ctx, offset,
2072                               offset + opaque_len, rcv_buf);
2073         if (maj_stat == GSS_S_CONTEXT_EXPIRED)
2074                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
2075         if (maj_stat != GSS_S_COMPLETE)
2076                 goto bad_unwrap;
2077         /* gss_unwrap decrypted the sequence number */
2078         if (be32_to_cpup(p++) != rqstp->rq_seqno)
2079                 goto bad_seqno;
2080
2081         /* gss_unwrap redacts the opaque blob from the head iovec.
2082          * rcv_buf has changed, thus the stream needs to be reset.
2083          */
2084         xdr_init_decode(xdr, rcv_buf, p, rqstp);
2085
2086         gss_update_rslack(task, cred, 2 + ctx->gc_gss_ctx->align,
2087                           2 + ctx->gc_gss_ctx->slack);
2088
2089         return 0;
2090 unwrap_failed:
2091         trace_rpcgss_unwrap_failed(task);
2092         return -EIO;
2093 bad_seqno:
2094         trace_rpcgss_bad_seqno(task, rqstp->rq_seqno, be32_to_cpup(--p));
2095         return -EIO;
2096 bad_unwrap:
2097         trace_rpcgss_unwrap(task, maj_stat);
2098         return -EIO;
2099 }
2100
2101 static bool
2102 gss_seq_is_newer(u32 new, u32 old)
2103 {
2104         return (s32)(new - old) > 0;
2105 }
2106
2107 static bool
2108 gss_xmit_need_reencode(struct rpc_task *task)
2109 {
2110         struct rpc_rqst *req = task->tk_rqstp;
2111         struct rpc_cred *cred = req->rq_cred;
2112         struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
2113         u32 win, seq_xmit = 0;
2114         bool ret = true;
2115
2116         if (!ctx)
2117                 goto out;
2118
2119         if (gss_seq_is_newer(req->rq_seqno, READ_ONCE(ctx->gc_seq)))
2120                 goto out_ctx;
2121
2122         seq_xmit = READ_ONCE(ctx->gc_seq_xmit);
2123         while (gss_seq_is_newer(req->rq_seqno, seq_xmit)) {
2124                 u32 tmp = seq_xmit;
2125
2126                 seq_xmit = cmpxchg(&ctx->gc_seq_xmit, tmp, req->rq_seqno);
2127                 if (seq_xmit == tmp) {
2128                         ret = false;
2129                         goto out_ctx;
2130                 }
2131         }
2132
2133         win = ctx->gc_win;
2134         if (win > 0)
2135                 ret = !gss_seq_is_newer(req->rq_seqno, seq_xmit - win);
2136
2137 out_ctx:
2138         gss_put_ctx(ctx);
2139 out:
2140         trace_rpcgss_need_reencode(task, seq_xmit, ret);
2141         return ret;
2142 }
2143
2144 static int
2145 gss_unwrap_resp(struct rpc_task *task, struct xdr_stream *xdr)
2146 {
2147         struct rpc_rqst *rqstp = task->tk_rqstp;
2148         struct rpc_cred *cred = rqstp->rq_cred;
2149         struct gss_cred *gss_cred = container_of(cred, struct gss_cred,
2150                         gc_base);
2151         struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
2152         int status = -EIO;
2153
2154         if (ctx->gc_proc != RPC_GSS_PROC_DATA)
2155                 goto out_decode;
2156         switch (gss_cred->gc_service) {
2157         case RPC_GSS_SVC_NONE:
2158                 status = gss_unwrap_resp_auth(task, cred);
2159                 break;
2160         case RPC_GSS_SVC_INTEGRITY:
2161                 status = gss_unwrap_resp_integ(task, cred, ctx, rqstp, xdr);
2162                 break;
2163         case RPC_GSS_SVC_PRIVACY:
2164                 status = gss_unwrap_resp_priv(task, cred, ctx, rqstp, xdr);
2165                 break;
2166         }
2167         if (status)
2168                 goto out;
2169
2170 out_decode:
2171         status = rpcauth_unwrap_resp_decode(task, xdr);
2172 out:
2173         gss_put_ctx(ctx);
2174         return status;
2175 }
2176
2177 static const struct rpc_authops authgss_ops = {
2178         .owner          = THIS_MODULE,
2179         .au_flavor      = RPC_AUTH_GSS,
2180         .au_name        = "RPCSEC_GSS",
2181         .create         = gss_create,
2182         .destroy        = gss_destroy,
2183         .hash_cred      = gss_hash_cred,
2184         .lookup_cred    = gss_lookup_cred,
2185         .crcreate       = gss_create_cred,
2186         .info2flavor    = gss_mech_info2flavor,
2187         .flavor2info    = gss_mech_flavor2info,
2188 };
2189
2190 static const struct rpc_credops gss_credops = {
2191         .cr_name                = "AUTH_GSS",
2192         .crdestroy              = gss_destroy_cred,
2193         .cr_init                = gss_cred_init,
2194         .crmatch                = gss_match,
2195         .crmarshal              = gss_marshal,
2196         .crrefresh              = gss_refresh,
2197         .crvalidate             = gss_validate,
2198         .crwrap_req             = gss_wrap_req,
2199         .crunwrap_resp          = gss_unwrap_resp,
2200         .crkey_timeout          = gss_key_timeout,
2201         .crstringify_acceptor   = gss_stringify_acceptor,
2202         .crneed_reencode        = gss_xmit_need_reencode,
2203 };
2204
2205 static const struct rpc_credops gss_nullops = {
2206         .cr_name                = "AUTH_GSS",
2207         .crdestroy              = gss_destroy_nullcred,
2208         .crmatch                = gss_match,
2209         .crmarshal              = gss_marshal,
2210         .crrefresh              = gss_refresh_null,
2211         .crvalidate             = gss_validate,
2212         .crwrap_req             = gss_wrap_req,
2213         .crunwrap_resp          = gss_unwrap_resp,
2214         .crstringify_acceptor   = gss_stringify_acceptor,
2215 };
2216
2217 static const struct rpc_pipe_ops gss_upcall_ops_v0 = {
2218         .upcall         = gss_v0_upcall,
2219         .downcall       = gss_pipe_downcall,
2220         .destroy_msg    = gss_pipe_destroy_msg,
2221         .open_pipe      = gss_pipe_open_v0,
2222         .release_pipe   = gss_pipe_release,
2223 };
2224
2225 static const struct rpc_pipe_ops gss_upcall_ops_v1 = {
2226         .upcall         = gss_v1_upcall,
2227         .downcall       = gss_pipe_downcall,
2228         .destroy_msg    = gss_pipe_destroy_msg,
2229         .open_pipe      = gss_pipe_open_v1,
2230         .release_pipe   = gss_pipe_release,
2231 };
2232
2233 static __net_init int rpcsec_gss_init_net(struct net *net)
2234 {
2235         return gss_svc_init_net(net);
2236 }
2237
2238 static __net_exit void rpcsec_gss_exit_net(struct net *net)
2239 {
2240         gss_svc_shutdown_net(net);
2241 }
2242
2243 static struct pernet_operations rpcsec_gss_net_ops = {
2244         .init = rpcsec_gss_init_net,
2245         .exit = rpcsec_gss_exit_net,
2246 };
2247
2248 /*
2249  * Initialize RPCSEC_GSS module
2250  */
2251 static int __init init_rpcsec_gss(void)
2252 {
2253         int err = 0;
2254
2255         err = rpcauth_register(&authgss_ops);
2256         if (err)
2257                 goto out;
2258         err = gss_svc_init();
2259         if (err)
2260                 goto out_unregister;
2261         err = register_pernet_subsys(&rpcsec_gss_net_ops);
2262         if (err)
2263                 goto out_svc_exit;
2264         rpc_init_wait_queue(&pipe_version_rpc_waitqueue, "gss pipe version");
2265         return 0;
2266 out_svc_exit:
2267         gss_svc_shutdown();
2268 out_unregister:
2269         rpcauth_unregister(&authgss_ops);
2270 out:
2271         return err;
2272 }
2273
2274 static void __exit exit_rpcsec_gss(void)
2275 {
2276         unregister_pernet_subsys(&rpcsec_gss_net_ops);
2277         gss_svc_shutdown();
2278         rpcauth_unregister(&authgss_ops);
2279         rcu_barrier(); /* Wait for completion of call_rcu()'s */
2280 }
2281
2282 MODULE_ALIAS("rpc-auth-6");
2283 MODULE_DESCRIPTION("Sun RPC Kerberos RPCSEC_GSS client authentication");
2284 MODULE_LICENSE("GPL");
2285 module_param_named(expired_cred_retry_delay,
2286                    gss_expired_cred_retry_delay,
2287                    uint, 0644);
2288 MODULE_PARM_DESC(expired_cred_retry_delay, "Timeout (in seconds) until "
2289                 "the RPC engine retries an expired credential");
2290
2291 module_param_named(key_expire_timeo,
2292                    gss_key_expire_timeo,
2293                    uint, 0644);
2294 MODULE_PARM_DESC(key_expire_timeo, "Time (in seconds) at the end of a "
2295                 "credential keys lifetime where the NFS layer cleans up "
2296                 "prior to key expiration");
2297
2298 module_init(init_rpcsec_gss)
2299 module_exit(exit_rpcsec_gss)