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   1 /*
   2  * linux/net/sunrpc/auth_gss/auth_gss.c
   3  *
   4  * RPCSEC_GSS client authentication.
   5  *
   6  *  Copyright (c) 2000 The Regents of the University of Michigan.
   7  *  All rights reserved.
   8  *
   9  *  Dug Song       <dugsong@monkey.org>
  10  *  Andy Adamson   <andros@umich.edu>
  11  *
  12  *  Redistribution and use in source and binary forms, with or without
  13  *  modification, are permitted provided that the following conditions
  14  *  are met:
  15  *
  16  *  1. Redistributions of source code must retain the above copyright
  17  *     notice, this list of conditions and the following disclaimer.
  18  *  2. Redistributions in binary form must reproduce the above copyright
  19  *     notice, this list of conditions and the following disclaimer in the
  20  *     documentation and/or other materials provided with the distribution.
  21  *  3. Neither the name of the University nor the names of its
  22  *     contributors may be used to endorse or promote products derived
  23  *     from this software without specific prior written permission.
  24  *
  25  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  26  *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  27  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  28  *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  29  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  30  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  31  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  32  *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  33  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  34  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  35  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  */
  37
  38
  39 #include <linux/module.h>
  40 #include <linux/init.h>
  41 #include <linux/types.h>
  42 #include <linux/slab.h>
  43 #include <linux/sched.h>
  44 #include <linux/pagemap.h>
  45 #include <linux/sunrpc/clnt.h>
  46 #include <linux/sunrpc/auth.h>
  47 #include <linux/sunrpc/auth_gss.h>
  48 #include <linux/sunrpc/svcauth_gss.h>
  49 #include <linux/sunrpc/gss_err.h>
  50 #include <linux/workqueue.h>
  51 #include <linux/sunrpc/rpc_pipe_fs.h>
  52 #include <linux/sunrpc/gss_api.h>
  53 #include <asm/uaccess.h>
  54
  55 static const struct rpc_authops authgss_ops;
  56
  57 static const struct rpc_credops gss_credops;
  58 static const struct rpc_credops gss_nullops;
  59
  60 #ifdef RPC_DEBUG
  61 # define RPCDBG_FACILITY        RPCDBG_AUTH
  62 #endif
  63
  64 #define GSS_CRED_SLACK          1024
  65 /* length of a krb5 verifier (48), plus data added before arguments when
  66  * using integrity (two 4-byte integers): */
  67 #define GSS_VERF_SLACK          100
  68
  69 struct gss_auth {
  70         struct kref kref;
  71         struct rpc_auth rpc_auth;
  72         struct gss_api_mech *mech;
  73         enum rpc_gss_svc service;
  74         struct rpc_clnt *client;
  75         /*
  76          * There are two upcall pipes; dentry[1], named "gssd", is used
  77          * for the new text-based upcall; dentry[0] is named after the
  78          * mechanism (for example, "krb5") and exists for
  79          * backwards-compatibility with older gssd's.
  80          */
  81         struct dentry *dentry[2];
  82 };
  83
  84 /* pipe_version >= 0 if and only if someone has a pipe open. */
  85 static int pipe_version = -1;
  86 static atomic_t pipe_users = ATOMIC_INIT(0);
  87 static DEFINE_SPINLOCK(pipe_version_lock);
  88 static struct rpc_wait_queue pipe_version_rpc_waitqueue;
  89 static DECLARE_WAIT_QUEUE_HEAD(pipe_version_waitqueue);
  90
  91 static void gss_free_ctx(struct gss_cl_ctx *);
  92 static struct rpc_pipe_ops gss_upcall_ops_v0;
  93 static struct rpc_pipe_ops gss_upcall_ops_v1;
  94
  95 static inline struct gss_cl_ctx *
  96 gss_get_ctx(struct gss_cl_ctx *ctx)
  97 {
  98         atomic_inc(&ctx->count);
  99         return ctx;
 100 }
 101
 102 static inline void
 103 gss_put_ctx(struct gss_cl_ctx *ctx)
 104 {
 105         if (atomic_dec_and_test(&ctx->count))
 106                 gss_free_ctx(ctx);
 107 }
 108
 109 /* gss_cred_set_ctx:
 110  * called by gss_upcall_callback and gss_create_upcall in order
 111  * to set the gss context. The actual exchange of an old context
 112  * and a new one is protected by the inode->i_lock.
 113  */
 114 static void
 115 gss_cred_set_ctx(struct rpc_cred *cred, struct gss_cl_ctx *ctx)
 116 {
 117         struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
 118
 119         if (!test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags))
 120                 return;
 121         gss_get_ctx(ctx);
 122         rcu_assign_pointer(gss_cred->gc_ctx, ctx);
 123         set_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
 124         smp_mb__before_clear_bit();
 125         clear_bit(RPCAUTH_CRED_NEW, &cred->cr_flags);
 126 }
 127
 128 static const void *
 129 simple_get_bytes(const void *p, const void *end, void *res, size_t len)
 130 {
 131         const void *q = (const void *)((const char *)p + len);
 132         if (unlikely(q > end || q < p))
 133                 return ERR_PTR(-EFAULT);
 134         memcpy(res, p, len);
 135         return q;
 136 }
 137
 138 static inline const void *
 139 simple_get_netobj(const void *p, const void *end, struct xdr_netobj *dest)
 140 {
 141         const void *q;
 142         unsigned int len;
 143
 144         p = simple_get_bytes(p, end, &len, sizeof(len));
 145         if (IS_ERR(p))
 146                 return p;
 147         q = (const void *)((const char *)p + len);
 148         if (unlikely(q > end || q < p))
 149                 return ERR_PTR(-EFAULT);
 150         dest->data = kmemdup(p, len, GFP_NOFS);
 151         if (unlikely(dest->data == NULL))
 152                 return ERR_PTR(-ENOMEM);
 153         dest->len = len;
 154         return q;
 155 }
 156
 157 static struct gss_cl_ctx *
 158 gss_cred_get_ctx(struct rpc_cred *cred)
 159 {
 160         struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
 161         struct gss_cl_ctx *ctx = NULL;
 162
 163         rcu_read_lock();
 164         if (gss_cred->gc_ctx)
 165                 ctx = gss_get_ctx(gss_cred->gc_ctx);
 166         rcu_read_unlock();
 167         return ctx;
 168 }
 169
 170 static struct gss_cl_ctx *
 171 gss_alloc_context(void)
 172 {
 173         struct gss_cl_ctx *ctx;
 174
 175         ctx = kzalloc(sizeof(*ctx), GFP_NOFS);
 176         if (ctx != NULL) {
 177                 ctx->gc_proc = RPC_GSS_PROC_DATA;
 178                 ctx->gc_seq = 1;        /* NetApp 6.4R1 doesn't accept seq. no. 0 */
 179                 spin_lock_init(&ctx->gc_seq_lock);
 180                 atomic_set(&ctx->count,1);
 181         }
 182         return ctx;
 183 }
 184
 185 #define GSSD_MIN_TIMEOUT (60 * 60)
 186 static const void *
 187 gss_fill_context(const void *p, const void *end, struct gss_cl_ctx *ctx, struct gss_api_mech *gm)
 188 {
 189         const void *q;
 190         unsigned int seclen;
 191         unsigned int timeout;
 192         u32 window_size;
 193         int ret;
 194
 195         /* First unsigned int gives the lifetime (in seconds) of the cred */
 196         p = simple_get_bytes(p, end, &timeout, sizeof(timeout));
 197         if (IS_ERR(p))
 198                 goto err;
 199         if (timeout == 0)
 200                 timeout = GSSD_MIN_TIMEOUT;
 201         ctx->gc_expiry = jiffies + (unsigned long)timeout * HZ * 3 / 4;
 202         /* Sequence number window. Determines the maximum number of simultaneous requests */
 203         p = simple_get_bytes(p, end, &window_size, sizeof(window_size));
 204         if (IS_ERR(p))
 205                 goto err;
 206         ctx->gc_win = window_size;
 207         /* gssd signals an error by passing ctx->gc_win = 0: */
 208         if (ctx->gc_win == 0) {
 209                 /* in which case, p points to  an error code which we ignore */
 210                 p = ERR_PTR(-EACCES);
 211                 goto err;
 212         }
 213         /* copy the opaque wire context */
 214         p = simple_get_netobj(p, end, &ctx->gc_wire_ctx);
 215         if (IS_ERR(p))
 216                 goto err;
 217         /* import the opaque security context */
 218         p  = simple_get_bytes(p, end, &seclen, sizeof(seclen));
 219         if (IS_ERR(p))
 220                 goto err;
 221         q = (const void *)((const char *)p + seclen);
 222         if (unlikely(q > end || q < p)) {
 223                 p = ERR_PTR(-EFAULT);
 224                 goto err;
 225         }
 226         ret = gss_import_sec_context(p, seclen, gm, &ctx->gc_gss_ctx);
 227         if (ret < 0) {
 228                 p = ERR_PTR(ret);
 229                 goto err;
 230         }
 231         return q;
 232 err:
 233         dprintk("RPC:       gss_fill_context returning %ld\n", -PTR_ERR(p));
 234         return p;
 235 }
 236
 237 #define UPCALL_BUF_LEN 128
 238
 239 struct gss_upcall_msg {
 240         atomic_t count;
 241         uid_t   uid;
 242         struct rpc_pipe_msg msg;
 243         struct list_head list;
 244         struct gss_auth *auth;
 245         struct rpc_inode *inode;
 246         struct rpc_wait_queue rpc_waitqueue;
 247         wait_queue_head_t waitqueue;
 248         struct gss_cl_ctx *ctx;
 249         char databuf[UPCALL_BUF_LEN];
 250 };
 251
 252 static int get_pipe_version(void)
 253 {
 254         int ret;
 255
 256         spin_lock(&pipe_version_lock);
 257         if (pipe_version >= 0) {
 258                 atomic_inc(&pipe_users);
 259                 ret = pipe_version;
 260         } else
 261                 ret = -EAGAIN;
 262         spin_unlock(&pipe_version_lock);
 263         return ret;
 264 }
 265
 266 static void put_pipe_version(void)
 267 {
 268         if (atomic_dec_and_lock(&pipe_users, &pipe_version_lock)) {
 269                 pipe_version = -1;
 270                 spin_unlock(&pipe_version_lock);
 271         }
 272 }
 273
 274 static void
 275 gss_release_msg(struct gss_upcall_msg *gss_msg)
 276 {
 277         if (!atomic_dec_and_test(&gss_msg->count))
 278                 return;
 279         put_pipe_version();
 280         BUG_ON(!list_empty(&gss_msg->list));
 281         if (gss_msg->ctx != NULL)
 282                 gss_put_ctx(gss_msg->ctx);
 283         rpc_destroy_wait_queue(&gss_msg->rpc_waitqueue);
 284         kfree(gss_msg);
 285 }
 286
 287 static struct gss_upcall_msg *
 288 __gss_find_upcall(struct rpc_inode *rpci, uid_t uid)
 289 {
 290         struct gss_upcall_msg *pos;
 291         list_for_each_entry(pos, &rpci->in_downcall, list) {
 292                 if (pos->uid != uid)
 293                         continue;
 294                 atomic_inc(&pos->count);
 295                 dprintk("RPC:       gss_find_upcall found msg %p\n", pos);
 296                 return pos;
 297         }
 298         dprintk("RPC:       gss_find_upcall found nothing\n");
 299         return NULL;
 300 }
 301
 302 /* Try to add an upcall to the pipefs queue.
 303  * If an upcall owned by our uid already exists, then we return a reference
 304  * to that upcall instead of adding the new upcall.
 305  */
 306 static inline struct gss_upcall_msg *
 307 gss_add_msg(struct gss_auth *gss_auth, struct gss_upcall_msg *gss_msg)
 308 {
 309         struct rpc_inode *rpci = gss_msg->inode;
 310         struct inode *inode = &rpci->vfs_inode;
 311         struct gss_upcall_msg *old;
 312
 313         spin_lock(&inode->i_lock);
 314         old = __gss_find_upcall(rpci, gss_msg->uid);
 315         if (old == NULL) {
 316                 atomic_inc(&gss_msg->count);
 317                 list_add(&gss_msg->list, &rpci->in_downcall);
 318         } else
 319                 gss_msg = old;
 320         spin_unlock(&inode->i_lock);
 321         return gss_msg;
 322 }
 323
 324 static void
 325 __gss_unhash_msg(struct gss_upcall_msg *gss_msg)
 326 {
 327         list_del_init(&gss_msg->list);
 328         rpc_wake_up_status(&gss_msg->rpc_waitqueue, gss_msg->msg.errno);
 329         wake_up_all(&gss_msg->waitqueue);
 330         atomic_dec(&gss_msg->count);
 331 }
 332
 333 static void
 334 gss_unhash_msg(struct gss_upcall_msg *gss_msg)
 335 {
 336         struct inode *inode = &gss_msg->inode->vfs_inode;
 337
 338         if (list_empty(&gss_msg->list))
 339                 return;
 340         spin_lock(&inode->i_lock);
 341         if (!list_empty(&gss_msg->list))
 342                 __gss_unhash_msg(gss_msg);
 343         spin_unlock(&inode->i_lock);
 344 }
 345
 346 static void
 347 gss_upcall_callback(struct rpc_task *task)
 348 {
 349         struct gss_cred *gss_cred = container_of(task->tk_msg.rpc_cred,
 350                         struct gss_cred, gc_base);
 351         struct gss_upcall_msg *gss_msg = gss_cred->gc_upcall;
 352         struct inode *inode = &gss_msg->inode->vfs_inode;
 353
 354         spin_lock(&inode->i_lock);
 355         if (gss_msg->ctx)
 356                 gss_cred_set_ctx(task->tk_msg.rpc_cred, gss_msg->ctx);
 357         else
 358                 task->tk_status = gss_msg->msg.errno;
 359         gss_cred->gc_upcall = NULL;
 360         rpc_wake_up_status(&gss_msg->rpc_waitqueue, gss_msg->msg.errno);
 361         spin_unlock(&inode->i_lock);
 362         gss_release_msg(gss_msg);
 363 }
 364
 365 static void gss_encode_v0_msg(struct gss_upcall_msg *gss_msg)
 366 {
 367         gss_msg->msg.data = &gss_msg->uid;
 368         gss_msg->msg.len = sizeof(gss_msg->uid);
 369 }
 370
 371 static void gss_encode_v1_msg(struct gss_upcall_msg *gss_msg,
 372                                 struct rpc_clnt *clnt)
 373 {
 374         char *p = gss_msg->databuf;
 375         int len = 0;
 376
 377         gss_msg->msg.len = sprintf(gss_msg->databuf, "mech=%s uid=%d ",
 378                                    gss_msg->auth->mech->gm_name,
 379                                    gss_msg->uid);
 380         p += gss_msg->msg.len;
 381         if (clnt->cl_principal) {
 382                 len = sprintf(p, "target=%s ", clnt->cl_principal);
 383                 p += len;
 384                 gss_msg->msg.len += len;
 385         }
 386         len = sprintf(p, "\n");
 387         gss_msg->msg.len += len;
 388
 389         gss_msg->msg.data = gss_msg->databuf;
 390         BUG_ON(gss_msg->msg.len > UPCALL_BUF_LEN);
 391 }
 392
 393 static void gss_encode_msg(struct gss_upcall_msg *gss_msg,
 394                                 struct rpc_clnt *clnt)
 395 {
 396         if (pipe_version == 0)
 397                 gss_encode_v0_msg(gss_msg);
 398         else /* pipe_version == 1 */
 399                 gss_encode_v1_msg(gss_msg, clnt);
 400 }
 401
 402 static inline struct gss_upcall_msg *
 403 gss_alloc_msg(struct gss_auth *gss_auth, uid_t uid, struct rpc_clnt *clnt)
 404 {
 405         struct gss_upcall_msg *gss_msg;
 406         int vers;
 407
 408         gss_msg = kzalloc(sizeof(*gss_msg), GFP_NOFS);
 409         if (gss_msg == NULL)
 410                 return ERR_PTR(-ENOMEM);
 411         vers = get_pipe_version();
 412         if (vers < 0) {
 413                 kfree(gss_msg);
 414                 return ERR_PTR(vers);
 415         }
 416         gss_msg->inode = RPC_I(gss_auth->dentry[vers]->d_inode);
 417         INIT_LIST_HEAD(&gss_msg->list);
 418         rpc_init_wait_queue(&gss_msg->rpc_waitqueue, "RPCSEC_GSS upcall waitq");
 419         init_waitqueue_head(&gss_msg->waitqueue);
 420         atomic_set(&gss_msg->count, 1);
 421         gss_msg->uid = uid;
 422         gss_msg->auth = gss_auth;
 423         gss_encode_msg(gss_msg, clnt);
 424         return gss_msg;
 425 }
 426
 427 static struct gss_upcall_msg *
 428 gss_setup_upcall(struct rpc_clnt *clnt, struct gss_auth *gss_auth, struct rpc_cred *cred)
 429 {
 430         struct gss_cred *gss_cred = container_of(cred,
 431                         struct gss_cred, gc_base);
 432         struct gss_upcall_msg *gss_new, *gss_msg;
 433         uid_t uid = cred->cr_uid;
 434
 435         /* Special case: rpc.gssd assumes that uid == 0 implies machine creds */
 436         if (gss_cred->gc_machine_cred != 0)
 437                 uid = 0;
 438
 439         gss_new = gss_alloc_msg(gss_auth, uid, clnt);
 440         if (IS_ERR(gss_new))
 441                 return gss_new;
 442         gss_msg = gss_add_msg(gss_auth, gss_new);
 443         if (gss_msg == gss_new) {
 444                 struct inode *inode = &gss_new->inode->vfs_inode;
 445                 int res = rpc_queue_upcall(inode, &gss_new->msg);
 446                 if (res) {
 447                         gss_unhash_msg(gss_new);
 448                         gss_msg = ERR_PTR(res);
 449                 }
 450         } else
 451                 gss_release_msg(gss_new);
 452         return gss_msg;
 453 }
 454
 455 static void warn_gssd(void)
 456 {
 457         static unsigned long ratelimit;
 458         unsigned long now = jiffies;
 459
 460         if (time_after(now, ratelimit)) {
 461                 printk(KERN_WARNING "RPC: AUTH_GSS upcall timed out.\n"
 462                                 "Please check user daemon is running.\n");
 463                 ratelimit = now + 15*HZ;
 464         }
 465 }
 466
 467 static inline int
 468 gss_refresh_upcall(struct rpc_task *task)
 469 {
 470         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 471         struct gss_auth *gss_auth = container_of(cred->cr_auth,
 472                         struct gss_auth, rpc_auth);
 473         struct gss_cred *gss_cred = container_of(cred,
 474                         struct gss_cred, gc_base);
 475         struct gss_upcall_msg *gss_msg;
 476         struct inode *inode;
 477         int err = 0;
 478
 479         dprintk("RPC: %5u gss_refresh_upcall for uid %u\n", task->tk_pid,
 480                                                                 cred->cr_uid);
 481         gss_msg = gss_setup_upcall(task->tk_client, gss_auth, cred);
 482         if (IS_ERR(gss_msg) == -EAGAIN) {
 483                 /* XXX: warning on the first, under the assumption we
 484                  * shouldn't normally hit this case on a refresh. */
 485                 warn_gssd();
 486                 task->tk_timeout = 15*HZ;
 487                 rpc_sleep_on(&pipe_version_rpc_waitqueue, task, NULL);
 488                 return 0;
 489         }
 490         if (IS_ERR(gss_msg)) {
 491                 err = PTR_ERR(gss_msg);
 492                 goto out;
 493         }
 494         inode = &gss_msg->inode->vfs_inode;
 495         spin_lock(&inode->i_lock);
 496         if (gss_cred->gc_upcall != NULL)
 497                 rpc_sleep_on(&gss_cred->gc_upcall->rpc_waitqueue, task, NULL);
 498         else if (gss_msg->ctx != NULL) {
 499                 gss_cred_set_ctx(task->tk_msg.rpc_cred, gss_msg->ctx);
 500                 gss_cred->gc_upcall = NULL;
 501                 rpc_wake_up_status(&gss_msg->rpc_waitqueue, gss_msg->msg.errno);
 502         } else if (gss_msg->msg.errno >= 0) {
 503                 task->tk_timeout = 0;
 504                 gss_cred->gc_upcall = gss_msg;
 505                 /* gss_upcall_callback will release the reference to gss_upcall_msg */
 506                 atomic_inc(&gss_msg->count);
 507                 rpc_sleep_on(&gss_msg->rpc_waitqueue, task, gss_upcall_callback);
 508         } else
 509                 err = gss_msg->msg.errno;
 510         spin_unlock(&inode->i_lock);
 511         gss_release_msg(gss_msg);
 512 out:
 513         dprintk("RPC: %5u gss_refresh_upcall for uid %u result %d\n",
 514                         task->tk_pid, cred->cr_uid, err);
 515         return err;
 516 }
 517
 518 static inline int
 519 gss_create_upcall(struct gss_auth *gss_auth, struct gss_cred *gss_cred)
 520 {
 521         struct inode *inode;
 522         struct rpc_cred *cred = &gss_cred->gc_base;
 523         struct gss_upcall_msg *gss_msg;
 524         DEFINE_WAIT(wait);
 525         int err = 0;
 526
 527         dprintk("RPC:       gss_upcall for uid %u\n", cred->cr_uid);
 528 retry:
 529         gss_msg = gss_setup_upcall(gss_auth->client, gss_auth, cred);
 530         if (PTR_ERR(gss_msg) == -EAGAIN) {
 531                 err = wait_event_interruptible_timeout(pipe_version_waitqueue,
 532                                 pipe_version >= 0, 15*HZ);
 533                 if (err)
 534                         goto out;
 535                 if (pipe_version < 0)
 536                         warn_gssd();
 537                 goto retry;
 538         }
 539         if (IS_ERR(gss_msg)) {
 540                 err = PTR_ERR(gss_msg);
 541                 goto out;
 542         }
 543         inode = &gss_msg->inode->vfs_inode;
 544         for (;;) {
 545                 prepare_to_wait(&gss_msg->waitqueue, &wait, TASK_INTERRUPTIBLE);
 546                 spin_lock(&inode->i_lock);
 547                 if (gss_msg->ctx != NULL || gss_msg->msg.errno < 0) {
 548                         break;
 549                 }
 550                 spin_unlock(&inode->i_lock);
 551                 if (signalled()) {
 552                         err = -ERESTARTSYS;
 553                         goto out_intr;
 554                 }
 555                 schedule();
 556         }
 557         if (gss_msg->ctx)
 558                 gss_cred_set_ctx(cred, gss_msg->ctx);
 559         else
 560                 err = gss_msg->msg.errno;
 561         spin_unlock(&inode->i_lock);
 562 out_intr:
 563         finish_wait(&gss_msg->waitqueue, &wait);
 564         gss_release_msg(gss_msg);
 565 out:
 566         dprintk("RPC:       gss_create_upcall for uid %u result %d\n",
 567                         cred->cr_uid, err);
 568         return err;
 569 }
 570
 571 static ssize_t
 572 gss_pipe_upcall(struct file *filp, struct rpc_pipe_msg *msg,
 573                 char __user *dst, size_t buflen)
 574 {
 575         char *data = (char *)msg->data + msg->copied;
 576         size_t mlen = min(msg->len, buflen);
 577         unsigned long left;
 578
 579         left = copy_to_user(dst, data, mlen);
 580         if (left == mlen) {
 581                 msg->errno = -EFAULT;
 582                 return -EFAULT;
 583         }
 584
 585         mlen -= left;
 586         msg->copied += mlen;
 587         msg->errno = 0;
 588         return mlen;
 589 }
 590
 591 #define MSG_BUF_MAXSIZE 1024
 592
 593 static ssize_t
 594 gss_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 595 {
 596         const void *p, *end;
 597         void *buf;
 598         struct gss_upcall_msg *gss_msg;
 599         struct inode *inode = filp->f_path.dentry->d_inode;
 600         struct gss_cl_ctx *ctx;
 601         uid_t uid;
 602         ssize_t err = -EFBIG;
 603
 604         if (mlen > MSG_BUF_MAXSIZE)
 605                 goto out;
 606         err = -ENOMEM;
 607         buf = kmalloc(mlen, GFP_NOFS);
 608         if (!buf)
 609                 goto out;
 610
 611         err = -EFAULT;
 612         if (copy_from_user(buf, src, mlen))
 613                 goto err;
 614
 615         end = (const void *)((char *)buf + mlen);
 616         p = simple_get_bytes(buf, end, &uid, sizeof(uid));
 617         if (IS_ERR(p)) {
 618                 err = PTR_ERR(p);
 619                 goto err;
 620         }
 621
 622         err = -ENOMEM;
 623         ctx = gss_alloc_context();
 624         if (ctx == NULL)
 625                 goto err;
 626
 627         err = -ENOENT;
 628         /* Find a matching upcall */
 629         spin_lock(&inode->i_lock);
 630         gss_msg = __gss_find_upcall(RPC_I(inode), uid);
 631         if (gss_msg == NULL) {
 632                 spin_unlock(&inode->i_lock);
 633                 goto err_put_ctx;
 634         }
 635         list_del_init(&gss_msg->list);
 636         spin_unlock(&inode->i_lock);
 637
 638         p = gss_fill_context(p, end, ctx, gss_msg->auth->mech);
 639         if (IS_ERR(p)) {
 640                 err = PTR_ERR(p);
 641                 gss_msg->msg.errno = (err == -EAGAIN) ? -EAGAIN : -EACCES;
 642                 goto err_release_msg;
 643         }
 644         gss_msg->ctx = gss_get_ctx(ctx);
 645         err = mlen;
 646
 647 err_release_msg:
 648         spin_lock(&inode->i_lock);
 649         __gss_unhash_msg(gss_msg);
 650         spin_unlock(&inode->i_lock);
 651         gss_release_msg(gss_msg);
 652 err_put_ctx:
 653         gss_put_ctx(ctx);
 654 err:
 655         kfree(buf);
 656 out:
 657         dprintk("RPC:       gss_pipe_downcall returning %Zd\n", err);
 658         return err;
 659 }
 660
 661 static int gss_pipe_open(struct inode *inode, int new_version)
 662 {
 663         int ret = 0;
 664
 665         spin_lock(&pipe_version_lock);
 666         if (pipe_version < 0) {
 667                 /* First open of any gss pipe determines the version: */
 668                 pipe_version = new_version;
 669                 rpc_wake_up(&pipe_version_rpc_waitqueue);
 670                 wake_up(&pipe_version_waitqueue);
 671         } else if (pipe_version != new_version) {
 672                 /* Trying to open a pipe of a different version */
 673                 ret = -EBUSY;
 674                 goto out;
 675         }
 676         atomic_inc(&pipe_users);
 677 out:
 678         spin_unlock(&pipe_version_lock);
 679         return ret;
 680
 681 }
 682
 683 static int gss_pipe_open_v0(struct inode *inode)
 684 {
 685         return gss_pipe_open(inode, 0);
 686 }
 687
 688 static int gss_pipe_open_v1(struct inode *inode)
 689 {
 690         return gss_pipe_open(inode, 1);
 691 }
 692
 693 static void
 694 gss_pipe_release(struct inode *inode)
 695 {
 696         struct rpc_inode *rpci = RPC_I(inode);
 697         struct gss_upcall_msg *gss_msg;
 698
 699         spin_lock(&inode->i_lock);
 700         while (!list_empty(&rpci->in_downcall)) {
 701
 702                 gss_msg = list_entry(rpci->in_downcall.next,
 703                                 struct gss_upcall_msg, list);
 704                 gss_msg->msg.errno = -EPIPE;
 705                 atomic_inc(&gss_msg->count);
 706                 __gss_unhash_msg(gss_msg);
 707                 spin_unlock(&inode->i_lock);
 708                 gss_release_msg(gss_msg);
 709                 spin_lock(&inode->i_lock);
 710         }
 711         spin_unlock(&inode->i_lock);
 712
 713         put_pipe_version();
 714 }
 715
 716 static void
 717 gss_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 718 {
 719         struct gss_upcall_msg *gss_msg = container_of(msg, struct gss_upcall_msg, msg);
 720
 721         if (msg->errno < 0) {
 722                 dprintk("RPC:       gss_pipe_destroy_msg releasing msg %p\n",
 723                                 gss_msg);
 724                 atomic_inc(&gss_msg->count);
 725                 gss_unhash_msg(gss_msg);
 726                 if (msg->errno == -ETIMEDOUT)
 727                         warn_gssd();
 728                 gss_release_msg(gss_msg);
 729         }
 730 }
 731
 732 /*
 733  * NOTE: we have the opportunity to use different
 734  * parameters based on the input flavor (which must be a pseudoflavor)
 735  */
 736 static struct rpc_auth *
 737 gss_create(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
 738 {
 739         struct gss_auth *gss_auth;
 740         struct rpc_auth * auth;
 741         int err = -ENOMEM; /* XXX? */
 742
 743         dprintk("RPC:       creating GSS authenticator for client %p\n", clnt);
 744
 745         if (!try_module_get(THIS_MODULE))
 746                 return ERR_PTR(err);
 747         if (!(gss_auth = kmalloc(sizeof(*gss_auth), GFP_KERNEL)))
 748                 goto out_dec;
 749         gss_auth->client = clnt;
 750         err = -EINVAL;
 751         gss_auth->mech = gss_mech_get_by_pseudoflavor(flavor);
 752         if (!gss_auth->mech) {
 753                 printk(KERN_WARNING "%s: Pseudoflavor %d not found!\n",
 754                                 __func__, flavor);
 755                 goto err_free;
 756         }
 757         gss_auth->service = gss_pseudoflavor_to_service(gss_auth->mech, flavor);
 758         if (gss_auth->service == 0)
 759                 goto err_put_mech;
 760         auth = &gss_auth->rpc_auth;
 761         auth->au_cslack = GSS_CRED_SLACK >> 2;
 762         auth->au_rslack = GSS_VERF_SLACK >> 2;
 763         auth->au_ops = &authgss_ops;
 764         auth->au_flavor = flavor;
 765         atomic_set(&auth->au_count, 1);
 766         kref_init(&gss_auth->kref);
 767
 768         /*
 769          * Note: if we created the old pipe first, then someone who
 770          * examined the directory at the right moment might conclude
 771          * that we supported only the old pipe.  So we instead create
 772          * the new pipe first.
 773          */
 774         gss_auth->dentry[1] = rpc_mkpipe(clnt->cl_dentry,
 775                                          "gssd",
 776                                          clnt, &gss_upcall_ops_v1,
 777                                          RPC_PIPE_WAIT_FOR_OPEN);
 778         if (IS_ERR(gss_auth->dentry[1])) {
 779                 err = PTR_ERR(gss_auth->dentry[1]);
 780                 goto err_put_mech;
 781         }
 782
 783         gss_auth->dentry[0] = rpc_mkpipe(clnt->cl_dentry,
 784                                          gss_auth->mech->gm_name,
 785                                          clnt, &gss_upcall_ops_v0,
 786                                          RPC_PIPE_WAIT_FOR_OPEN);
 787         if (IS_ERR(gss_auth->dentry[0])) {
 788                 err = PTR_ERR(gss_auth->dentry[0]);
 789                 goto err_unlink_pipe_1;
 790         }
 791         err = rpcauth_init_credcache(auth);
 792         if (err)
 793                 goto err_unlink_pipe_0;
 794
 795         return auth;
 796 err_unlink_pipe_0:
 797         rpc_unlink(gss_auth->dentry[0]);
 798 err_unlink_pipe_1:
 799         rpc_unlink(gss_auth->dentry[1]);
 800 err_put_mech:
 801         gss_mech_put(gss_auth->mech);
 802 err_free:
 803         kfree(gss_auth);
 804 out_dec:
 805         module_put(THIS_MODULE);
 806         return ERR_PTR(err);
 807 }
 808
 809 static void
 810 gss_free(struct gss_auth *gss_auth)
 811 {
 812         rpc_unlink(gss_auth->dentry[1]);
 813         rpc_unlink(gss_auth->dentry[0]);
 814         gss_mech_put(gss_auth->mech);
 815
 816         kfree(gss_auth);
 817         module_put(THIS_MODULE);
 818 }
 819
 820 static void
 821 gss_free_callback(struct kref *kref)
 822 {
 823         struct gss_auth *gss_auth = container_of(kref, struct gss_auth, kref);
 824
 825         gss_free(gss_auth);
 826 }
 827
 828 static void
 829 gss_destroy(struct rpc_auth *auth)
 830 {
 831         struct gss_auth *gss_auth;
 832
 833         dprintk("RPC:       destroying GSS authenticator %p flavor %d\n",
 834                         auth, auth->au_flavor);
 835
 836         rpcauth_destroy_credcache(auth);
 837
 838         gss_auth = container_of(auth, struct gss_auth, rpc_auth);
 839         kref_put(&gss_auth->kref, gss_free_callback);
 840 }
 841
 842 /*
 843  * gss_destroying_context will cause the RPCSEC_GSS to send a NULL RPC call
 844  * to the server with the GSS control procedure field set to
 845  * RPC_GSS_PROC_DESTROY. This should normally cause the server to release
 846  * all RPCSEC_GSS state associated with that context.
 847  */
 848 static int
 849 gss_destroying_context(struct rpc_cred *cred)
 850 {
 851         struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
 852         struct gss_auth *gss_auth = container_of(cred->cr_auth, struct gss_auth, rpc_auth);
 853         struct rpc_task *task;
 854
 855         if (gss_cred->gc_ctx == NULL ||
 856             test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) == 0)
 857                 return 0;
 858
 859         gss_cred->gc_ctx->gc_proc = RPC_GSS_PROC_DESTROY;
 860         cred->cr_ops = &gss_nullops;
 861
 862         /* Take a reference to ensure the cred will be destroyed either
 863          * by the RPC call or by the put_rpccred() below */
 864         get_rpccred(cred);
 865
 866         task = rpc_call_null(gss_auth->client, cred, RPC_TASK_ASYNC|RPC_TASK_SOFT);
 867         if (!IS_ERR(task))
 868                 rpc_put_task(task);
 869
 870         put_rpccred(cred);
 871         return 1;
 872 }
 873
 874 /* gss_destroy_cred (and gss_free_ctx) are used to clean up after failure
 875  * to create a new cred or context, so they check that things have been
 876  * allocated before freeing them. */
 877 static void
 878 gss_do_free_ctx(struct gss_cl_ctx *ctx)
 879 {
 880         dprintk("RPC:       gss_free_ctx\n");
 881
 882         kfree(ctx->gc_wire_ctx.data);
 883         kfree(ctx);
 884 }
 885
 886 static void
 887 gss_free_ctx_callback(struct rcu_head *head)
 888 {
 889         struct gss_cl_ctx *ctx = container_of(head, struct gss_cl_ctx, gc_rcu);
 890         gss_do_free_ctx(ctx);
 891 }
 892
 893 static void
 894 gss_free_ctx(struct gss_cl_ctx *ctx)
 895 {
 896         struct gss_ctx *gc_gss_ctx;
 897
 898         gc_gss_ctx = rcu_dereference(ctx->gc_gss_ctx);
 899         rcu_assign_pointer(ctx->gc_gss_ctx, NULL);
 900         call_rcu(&ctx->gc_rcu, gss_free_ctx_callback);
 901         if (gc_gss_ctx)
 902                 gss_delete_sec_context(&gc_gss_ctx);
 903 }
 904
 905 static void
 906 gss_free_cred(struct gss_cred *gss_cred)
 907 {
 908         dprintk("RPC:       gss_free_cred %p\n", gss_cred);
 909         kfree(gss_cred);
 910 }
 911
 912 static void
 913 gss_free_cred_callback(struct rcu_head *head)
 914 {
 915         struct gss_cred *gss_cred = container_of(head, struct gss_cred, gc_base.cr_rcu);
 916         gss_free_cred(gss_cred);
 917 }
 918
 919 static void
 920 gss_destroy_nullcred(struct rpc_cred *cred)
 921 {
 922         struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
 923         struct gss_auth *gss_auth = container_of(cred->cr_auth, struct gss_auth, rpc_auth);
 924         struct gss_cl_ctx *ctx = gss_cred->gc_ctx;
 925
 926         rcu_assign_pointer(gss_cred->gc_ctx, NULL);
 927         call_rcu(&cred->cr_rcu, gss_free_cred_callback);
 928         if (ctx)
 929                 gss_put_ctx(ctx);
 930         kref_put(&gss_auth->kref, gss_free_callback);
 931 }
 932
 933 static void
 934 gss_destroy_cred(struct rpc_cred *cred)
 935 {
 936
 937         if (gss_destroying_context(cred))
 938                 return;
 939         gss_destroy_nullcred(cred);
 940 }
 941
 942 /*
 943  * Lookup RPCSEC_GSS cred for the current process
 944  */
 945 static struct rpc_cred *
 946 gss_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
 947 {
 948         return rpcauth_lookup_credcache(auth, acred, flags);
 949 }
 950
 951 static struct rpc_cred *
 952 gss_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
 953 {
 954         struct gss_auth *gss_auth = container_of(auth, struct gss_auth, rpc_auth);
 955         struct gss_cred *cred = NULL;
 956         int err = -ENOMEM;
 957
 958         dprintk("RPC:       gss_create_cred for uid %d, flavor %d\n",
 959                 acred->uid, auth->au_flavor);
 960
 961         if (!(cred = kzalloc(sizeof(*cred), GFP_NOFS)))
 962                 goto out_err;
 963
 964         rpcauth_init_cred(&cred->gc_base, acred, auth, &gss_credops);
 965         /*
 966          * Note: in order to force a call to call_refresh(), we deliberately
 967          * fail to flag the credential as RPCAUTH_CRED_UPTODATE.
 968          */
 969         cred->gc_base.cr_flags = 1UL << RPCAUTH_CRED_NEW;
 970         cred->gc_service = gss_auth->service;
 971         cred->gc_machine_cred = acred->machine_cred;
 972         kref_get(&gss_auth->kref);
 973         return &cred->gc_base;
 974
 975 out_err:
 976         dprintk("RPC:       gss_create_cred failed with error %d\n", err);
 977         return ERR_PTR(err);
 978 }
 979
 980 static int
 981 gss_cred_init(struct rpc_auth *auth, struct rpc_cred *cred)
 982 {
 983         struct gss_auth *gss_auth = container_of(auth, struct gss_auth, rpc_auth);
 984         struct gss_cred *gss_cred = container_of(cred,struct gss_cred, gc_base);
 985         int err;
 986
 987         do {
 988                 err = gss_create_upcall(gss_auth, gss_cred);
 989         } while (err == -EAGAIN);
 990         return err;
 991 }
 992
 993 static int
 994 gss_match(struct auth_cred *acred, struct rpc_cred *rc, int flags)
 995 {
 996         struct gss_cred *gss_cred = container_of(rc, struct gss_cred, gc_base);
 997
 998         if (test_bit(RPCAUTH_CRED_NEW, &rc->cr_flags))
 999                 goto out;
1000         /* Don't match with creds that have expired. */
1001         if (time_after(jiffies, gss_cred->gc_ctx->gc_expiry))
1002                 return 0;
1003         if (!test_bit(RPCAUTH_CRED_UPTODATE, &rc->cr_flags))
1004                 return 0;
1005 out:
1006         if (acred->machine_cred != gss_cred->gc_machine_cred)
1007                 return 0;
1008         return (rc->cr_uid == acred->uid);
1009 }
1010
1011 /*
1012 * Marshal credentials.
1013 * Maybe we should keep a cached credential for performance reasons.
1014 */
1015 static __be32 *
1016 gss_marshal(struct rpc_task *task, __be32 *p)
1017 {
1018         struct rpc_cred *cred = task->tk_msg.rpc_cred;
1019         struct gss_cred *gss_cred = container_of(cred, struct gss_cred,
1020                                                  gc_base);
1021         struct gss_cl_ctx       *ctx = gss_cred_get_ctx(cred);
1022         __be32          *cred_len;
1023         struct rpc_rqst *req = task->tk_rqstp;
1024         u32             maj_stat = 0;
1025         struct xdr_netobj mic;
1026         struct kvec     iov;
1027         struct xdr_buf  verf_buf;
1028
1029         dprintk("RPC: %5u gss_marshal\n", task->tk_pid);
1030
1031         *p++ = htonl(RPC_AUTH_GSS);
1032         cred_len = p++;
1033
1034         spin_lock(&ctx->gc_seq_lock);
1035         req->rq_seqno = ctx->gc_seq++;
1036         spin_unlock(&ctx->gc_seq_lock);
1037
1038         *p++ = htonl((u32) RPC_GSS_VERSION);
1039         *p++ = htonl((u32) ctx->gc_proc);
1040         *p++ = htonl((u32) req->rq_seqno);
1041         *p++ = htonl((u32) gss_cred->gc_service);
1042         p = xdr_encode_netobj(p, &ctx->gc_wire_ctx);
1043         *cred_len = htonl((p - (cred_len + 1)) << 2);
1044
1045         /* We compute the checksum for the verifier over the xdr-encoded bytes
1046          * starting with the xid and ending at the end of the credential: */
1047         iov.iov_base = xprt_skip_transport_header(task->tk_xprt,
1048                                         req->rq_snd_buf.head[0].iov_base);
1049         iov.iov_len = (u8 *)p - (u8 *)iov.iov_base;
1050         xdr_buf_from_iov(&iov, &verf_buf);
1051
1052         /* set verifier flavor*/
1053         *p++ = htonl(RPC_AUTH_GSS);
1054
1055         mic.data = (u8 *)(p + 1);
1056         maj_stat = gss_get_mic(ctx->gc_gss_ctx, &verf_buf, &mic);
1057         if (maj_stat == GSS_S_CONTEXT_EXPIRED) {
1058                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1059         } else if (maj_stat != 0) {
1060                 printk("gss_marshal: gss_get_mic FAILED (%d)\n", maj_stat);
1061                 goto out_put_ctx;
1062         }
1063         p = xdr_encode_opaque(p, NULL, mic.len);
1064         gss_put_ctx(ctx);
1065         return p;
1066 out_put_ctx:
1067         gss_put_ctx(ctx);
1068         return NULL;
1069 }
1070
1071 static int gss_renew_cred(struct rpc_task *task)
1072 {
1073         struct rpc_cred *oldcred = task->tk_msg.rpc_cred;
1074         struct gss_cred *gss_cred = container_of(oldcred,
1075                                                  struct gss_cred,
1076                                                  gc_base);
1077         struct rpc_auth *auth = oldcred->cr_auth;
1078         struct auth_cred acred = {
1079                 .uid = oldcred->cr_uid,
1080                 .machine_cred = gss_cred->gc_machine_cred,
1081         };
1082         struct rpc_cred *new;
1083
1084         new = gss_lookup_cred(auth, &acred, RPCAUTH_LOOKUP_NEW);
1085         if (IS_ERR(new))
1086                 return PTR_ERR(new);
1087         task->tk_msg.rpc_cred = new;
1088         put_rpccred(oldcred);
1089         return 0;
1090 }
1091
1092 /*
1093 * Refresh credentials. XXX - finish
1094 */
1095 static int
1096 gss_refresh(struct rpc_task *task)
1097 {
1098         struct rpc_cred *cred = task->tk_msg.rpc_cred;
1099         int ret = 0;
1100
1101         if (!test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags) &&
1102                         !test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags)) {
1103                 ret = gss_renew_cred(task);
1104                 if (ret < 0)
1105                         goto out;
1106                 cred = task->tk_msg.rpc_cred;
1107         }
1108
1109         if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags))
1110                 ret = gss_refresh_upcall(task);
1111 out:
1112         return ret;
1113 }
1114
1115 /* Dummy refresh routine: used only when destroying the context */
1116 static int
1117 gss_refresh_null(struct rpc_task *task)
1118 {
1119         return -EACCES;
1120 }
1121
1122 static __be32 *
1123 gss_validate(struct rpc_task *task, __be32 *p)
1124 {
1125         struct rpc_cred *cred = task->tk_msg.rpc_cred;
1126         struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
1127         __be32          seq;
1128         struct kvec     iov;
1129         struct xdr_buf  verf_buf;
1130         struct xdr_netobj mic;
1131         u32             flav,len;
1132         u32             maj_stat;
1133
1134         dprintk("RPC: %5u gss_validate\n", task->tk_pid);
1135
1136         flav = ntohl(*p++);
1137         if ((len = ntohl(*p++)) > RPC_MAX_AUTH_SIZE)
1138                 goto out_bad;
1139         if (flav != RPC_AUTH_GSS)
1140                 goto out_bad;
1141         seq = htonl(task->tk_rqstp->rq_seqno);
1142         iov.iov_base = &seq;
1143         iov.iov_len = sizeof(seq);
1144         xdr_buf_from_iov(&iov, &verf_buf);
1145         mic.data = (u8 *)p;
1146         mic.len = len;
1147
1148         maj_stat = gss_verify_mic(ctx->gc_gss_ctx, &verf_buf, &mic);
1149         if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1150                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1151         if (maj_stat) {
1152                 dprintk("RPC: %5u gss_validate: gss_verify_mic returned "
1153                                 "error 0x%08x\n", task->tk_pid, maj_stat);
1154                 goto out_bad;
1155         }
1156         /* We leave it to unwrap to calculate au_rslack. For now we just
1157          * calculate the length of the verifier: */
1158         cred->cr_auth->au_verfsize = XDR_QUADLEN(len) + 2;
1159         gss_put_ctx(ctx);
1160         dprintk("RPC: %5u gss_validate: gss_verify_mic succeeded.\n",
1161                         task->tk_pid);
1162         return p + XDR_QUADLEN(len);
1163 out_bad:
1164         gss_put_ctx(ctx);
1165         dprintk("RPC: %5u gss_validate failed.\n", task->tk_pid);
1166         return NULL;
1167 }
1168
1169 static inline int
1170 gss_wrap_req_integ(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
1171                 kxdrproc_t encode, struct rpc_rqst *rqstp, __be32 *p, void *obj)
1172 {
1173         struct xdr_buf  *snd_buf = &rqstp->rq_snd_buf;
1174         struct xdr_buf  integ_buf;
1175         __be32          *integ_len = NULL;
1176         struct xdr_netobj mic;
1177         u32             offset;
1178         __be32          *q;
1179         struct kvec     *iov;
1180         u32             maj_stat = 0;
1181         int             status = -EIO;
1182
1183         integ_len = p++;
1184         offset = (u8 *)p - (u8 *)snd_buf->head[0].iov_base;
1185         *p++ = htonl(rqstp->rq_seqno);
1186
1187         status = encode(rqstp, p, obj);
1188         if (status)
1189                 return status;
1190
1191         if (xdr_buf_subsegment(snd_buf, &integ_buf,
1192                                 offset, snd_buf->len - offset))
1193                 return status;
1194         *integ_len = htonl(integ_buf.len);
1195
1196         /* guess whether we're in the head or the tail: */
1197         if (snd_buf->page_len || snd_buf->tail[0].iov_len)
1198                 iov = snd_buf->tail;
1199         else
1200                 iov = snd_buf->head;
1201         p = iov->iov_base + iov->iov_len;
1202         mic.data = (u8 *)(p + 1);
1203
1204         maj_stat = gss_get_mic(ctx->gc_gss_ctx, &integ_buf, &mic);
1205         status = -EIO; /* XXX? */
1206         if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1207                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1208         else if (maj_stat)
1209                 return status;
1210         q = xdr_encode_opaque(p, NULL, mic.len);
1211
1212         offset = (u8 *)q - (u8 *)p;
1213         iov->iov_len += offset;
1214         snd_buf->len += offset;
1215         return 0;
1216 }
1217
1218 static void
1219 priv_release_snd_buf(struct rpc_rqst *rqstp)
1220 {
1221         int i;
1222
1223         for (i=0; i < rqstp->rq_enc_pages_num; i++)
1224                 __free_page(rqstp->rq_enc_pages[i]);
1225         kfree(rqstp->rq_enc_pages);
1226 }
1227
1228 static int
1229 alloc_enc_pages(struct rpc_rqst *rqstp)
1230 {
1231         struct xdr_buf *snd_buf = &rqstp->rq_snd_buf;
1232         int first, last, i;
1233
1234         if (snd_buf->page_len == 0) {
1235                 rqstp->rq_enc_pages_num = 0;
1236                 return 0;
1237         }
1238
1239         first = snd_buf->page_base >> PAGE_CACHE_SHIFT;
1240         last = (snd_buf->page_base + snd_buf->page_len - 1) >> PAGE_CACHE_SHIFT;
1241         rqstp->rq_enc_pages_num = last - first + 1 + 1;
1242         rqstp->rq_enc_pages
1243                 = kmalloc(rqstp->rq_enc_pages_num * sizeof(struct page *),
1244                                 GFP_NOFS);
1245         if (!rqstp->rq_enc_pages)
1246                 goto out;
1247         for (i=0; i < rqstp->rq_enc_pages_num; i++) {
1248                 rqstp->rq_enc_pages[i] = alloc_page(GFP_NOFS);
1249                 if (rqstp->rq_enc_pages[i] == NULL)
1250                         goto out_free;
1251         }
1252         rqstp->rq_release_snd_buf = priv_release_snd_buf;
1253         return 0;
1254 out_free:
1255         for (i--; i >= 0; i--) {
1256                 __free_page(rqstp->rq_enc_pages[i]);
1257         }
1258 out:
1259         return -EAGAIN;
1260 }
1261
1262 static inline int
1263 gss_wrap_req_priv(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
1264                 kxdrproc_t encode, struct rpc_rqst *rqstp, __be32 *p, void *obj)
1265 {
1266         struct xdr_buf  *snd_buf = &rqstp->rq_snd_buf;
1267         u32             offset;
1268         u32             maj_stat;
1269         int             status;
1270         __be32          *opaque_len;
1271         struct page     **inpages;
1272         int             first;
1273         int             pad;
1274         struct kvec     *iov;
1275         char            *tmp;
1276
1277         opaque_len = p++;
1278         offset = (u8 *)p - (u8 *)snd_buf->head[0].iov_base;
1279         *p++ = htonl(rqstp->rq_seqno);
1280
1281         status = encode(rqstp, p, obj);
1282         if (status)
1283                 return status;
1284
1285         status = alloc_enc_pages(rqstp);
1286         if (status)
1287                 return status;
1288         first = snd_buf->page_base >> PAGE_CACHE_SHIFT;
1289         inpages = snd_buf->pages + first;
1290         snd_buf->pages = rqstp->rq_enc_pages;
1291         snd_buf->page_base -= first << PAGE_CACHE_SHIFT;
1292         /* Give the tail its own page, in case we need extra space in the
1293          * head when wrapping: */
1294         if (snd_buf->page_len || snd_buf->tail[0].iov_len) {
1295                 tmp = page_address(rqstp->rq_enc_pages[rqstp->rq_enc_pages_num - 1]);
1296                 memcpy(tmp, snd_buf->tail[0].iov_base, snd_buf->tail[0].iov_len);
1297                 snd_buf->tail[0].iov_base = tmp;
1298         }
1299         maj_stat = gss_wrap(ctx->gc_gss_ctx, offset, snd_buf, inpages);
1300         /* RPC_SLACK_SPACE should prevent this ever happening: */
1301         BUG_ON(snd_buf->len > snd_buf->buflen);
1302         status = -EIO;
1303         /* We're assuming that when GSS_S_CONTEXT_EXPIRED, the encryption was
1304          * done anyway, so it's safe to put the request on the wire: */
1305         if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1306                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1307         else if (maj_stat)
1308                 return status;
1309
1310         *opaque_len = htonl(snd_buf->len - offset);
1311         /* guess whether we're in the head or the tail: */
1312         if (snd_buf->page_len || snd_buf->tail[0].iov_len)
1313                 iov = snd_buf->tail;
1314         else
1315                 iov = snd_buf->head;
1316         p = iov->iov_base + iov->iov_len;
1317         pad = 3 - ((snd_buf->len - offset - 1) & 3);
1318         memset(p, 0, pad);
1319         iov->iov_len += pad;
1320         snd_buf->len += pad;
1321
1322         return 0;
1323 }
1324
1325 static int
1326 gss_wrap_req(struct rpc_task *task,
1327              kxdrproc_t encode, void *rqstp, __be32 *p, void *obj)
1328 {
1329         struct rpc_cred *cred = task->tk_msg.rpc_cred;
1330         struct gss_cred *gss_cred = container_of(cred, struct gss_cred,
1331                         gc_base);
1332         struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
1333         int             status = -EIO;
1334
1335         dprintk("RPC: %5u gss_wrap_req\n", task->tk_pid);
1336         if (ctx->gc_proc != RPC_GSS_PROC_DATA) {
1337                 /* The spec seems a little ambiguous here, but I think that not
1338                  * wrapping context destruction requests makes the most sense.
1339                  */
1340                 status = encode(rqstp, p, obj);
1341                 goto out;
1342         }
1343         switch (gss_cred->gc_service) {
1344                 case RPC_GSS_SVC_NONE:
1345                         status = encode(rqstp, p, obj);
1346                         break;
1347                 case RPC_GSS_SVC_INTEGRITY:
1348                         status = gss_wrap_req_integ(cred, ctx, encode,
1349                                                                 rqstp, p, obj);
1350                         break;
1351                 case RPC_GSS_SVC_PRIVACY:
1352                         status = gss_wrap_req_priv(cred, ctx, encode,
1353                                         rqstp, p, obj);
1354                         break;
1355         }
1356 out:
1357         gss_put_ctx(ctx);
1358         dprintk("RPC: %5u gss_wrap_req returning %d\n", task->tk_pid, status);
1359         return status;
1360 }
1361
1362 static inline int
1363 gss_unwrap_resp_integ(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
1364                 struct rpc_rqst *rqstp, __be32 **p)
1365 {
1366         struct xdr_buf  *rcv_buf = &rqstp->rq_rcv_buf;
1367         struct xdr_buf integ_buf;
1368         struct xdr_netobj mic;
1369         u32 data_offset, mic_offset;
1370         u32 integ_len;
1371         u32 maj_stat;
1372         int status = -EIO;
1373
1374         integ_len = ntohl(*(*p)++);
1375         if (integ_len & 3)
1376                 return status;
1377         data_offset = (u8 *)(*p) - (u8 *)rcv_buf->head[0].iov_base;
1378         mic_offset = integ_len + data_offset;
1379         if (mic_offset > rcv_buf->len)
1380                 return status;
1381         if (ntohl(*(*p)++) != rqstp->rq_seqno)
1382                 return status;
1383
1384         if (xdr_buf_subsegment(rcv_buf, &integ_buf, data_offset,
1385                                 mic_offset - data_offset))
1386                 return status;
1387
1388         if (xdr_buf_read_netobj(rcv_buf, &mic, mic_offset))
1389                 return status;
1390
1391         maj_stat = gss_verify_mic(ctx->gc_gss_ctx, &integ_buf, &mic);
1392         if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1393                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1394         if (maj_stat != GSS_S_COMPLETE)
1395                 return status;
1396         return 0;
1397 }
1398
1399 static inline int
1400 gss_unwrap_resp_priv(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
1401                 struct rpc_rqst *rqstp, __be32 **p)
1402 {
1403         struct xdr_buf  *rcv_buf = &rqstp->rq_rcv_buf;
1404         u32 offset;
1405         u32 opaque_len;
1406         u32 maj_stat;
1407         int status = -EIO;
1408
1409         opaque_len = ntohl(*(*p)++);
1410         offset = (u8 *)(*p) - (u8 *)rcv_buf->head[0].iov_base;
1411         if (offset + opaque_len > rcv_buf->len)
1412                 return status;
1413         /* remove padding: */
1414         rcv_buf->len = offset + opaque_len;
1415
1416         maj_stat = gss_unwrap(ctx->gc_gss_ctx, offset, rcv_buf);
1417         if (maj_stat == GSS_S_CONTEXT_EXPIRED)
1418                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
1419         if (maj_stat != GSS_S_COMPLETE)
1420                 return status;
1421         if (ntohl(*(*p)++) != rqstp->rq_seqno)
1422                 return status;
1423
1424         return 0;
1425 }
1426
1427
1428 static int
1429 gss_unwrap_resp(struct rpc_task *task,
1430                 kxdrproc_t decode, void *rqstp, __be32 *p, void *obj)
1431 {
1432         struct rpc_cred *cred = task->tk_msg.rpc_cred;
1433         struct gss_cred *gss_cred = container_of(cred, struct gss_cred,
1434                         gc_base);
1435         struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
1436         __be32          *savedp = p;
1437         struct kvec     *head = ((struct rpc_rqst *)rqstp)->rq_rcv_buf.head;
1438         int             savedlen = head->iov_len;
1439         int             status = -EIO;
1440
1441         if (ctx->gc_proc != RPC_GSS_PROC_DATA)
1442                 goto out_decode;
1443         switch (gss_cred->gc_service) {
1444                 case RPC_GSS_SVC_NONE:
1445                         break;
1446                 case RPC_GSS_SVC_INTEGRITY:
1447                         status = gss_unwrap_resp_integ(cred, ctx, rqstp, &p);
1448                         if (status)
1449                                 goto out;
1450                         break;
1451                 case RPC_GSS_SVC_PRIVACY:
1452                         status = gss_unwrap_resp_priv(cred, ctx, rqstp, &p);
1453                         if (status)
1454                                 goto out;
1455                         break;
1456         }
1457         /* take into account extra slack for integrity and privacy cases: */
1458         cred->cr_auth->au_rslack = cred->cr_auth->au_verfsize + (p - savedp)
1459                                                 + (savedlen - head->iov_len);
1460 out_decode:
1461         status = decode(rqstp, p, obj);
1462 out:
1463         gss_put_ctx(ctx);
1464         dprintk("RPC: %5u gss_unwrap_resp returning %d\n", task->tk_pid,
1465                         status);
1466         return status;
1467 }
1468
1469 static const struct rpc_authops authgss_ops = {
1470         .owner          = THIS_MODULE,
1471         .au_flavor      = RPC_AUTH_GSS,
1472         .au_name        = "RPCSEC_GSS",
1473         .create         = gss_create,
1474         .destroy        = gss_destroy,
1475         .lookup_cred    = gss_lookup_cred,
1476         .crcreate       = gss_create_cred
1477 };
1478
1479 static const struct rpc_credops gss_credops = {
1480         .cr_name        = "AUTH_GSS",
1481         .crdestroy      = gss_destroy_cred,
1482         .cr_init        = gss_cred_init,
1483         .crbind         = rpcauth_generic_bind_cred,
1484         .crmatch        = gss_match,
1485         .crmarshal      = gss_marshal,
1486         .crrefresh      = gss_refresh,
1487         .crvalidate     = gss_validate,
1488         .crwrap_req     = gss_wrap_req,
1489         .crunwrap_resp  = gss_unwrap_resp,
1490 };
1491
1492 static const struct rpc_credops gss_nullops = {
1493         .cr_name        = "AUTH_GSS",
1494         .crdestroy      = gss_destroy_nullcred,
1495         .crbind         = rpcauth_generic_bind_cred,
1496         .crmatch        = gss_match,
1497         .crmarshal      = gss_marshal,
1498         .crrefresh      = gss_refresh_null,
1499         .crvalidate     = gss_validate,
1500         .crwrap_req     = gss_wrap_req,
1501         .crunwrap_resp  = gss_unwrap_resp,
1502 };
1503
1504 static struct rpc_pipe_ops gss_upcall_ops_v0 = {
1505         .upcall         = gss_pipe_upcall,
1506         .downcall       = gss_pipe_downcall,
1507         .destroy_msg    = gss_pipe_destroy_msg,
1508         .open_pipe      = gss_pipe_open_v0,
1509         .release_pipe   = gss_pipe_release,
1510 };
1511
1512 static struct rpc_pipe_ops gss_upcall_ops_v1 = {
1513         .upcall         = gss_pipe_upcall,
1514         .downcall       = gss_pipe_downcall,
1515         .destroy_msg    = gss_pipe_destroy_msg,
1516         .open_pipe      = gss_pipe_open_v1,
1517         .release_pipe   = gss_pipe_release,
1518 };
1519
1520 /*
1521  * Initialize RPCSEC_GSS module
1522  */
1523 static int __init init_rpcsec_gss(void)
1524 {
1525         int err = 0;
1526
1527         err = rpcauth_register(&authgss_ops);
1528         if (err)
1529                 goto out;
1530         err = gss_svc_init();
1531         if (err)
1532                 goto out_unregister;
1533         rpc_init_wait_queue(&pipe_version_rpc_waitqueue, "gss pipe version");
1534         return 0;
1535 out_unregister:
1536         rpcauth_unregister(&authgss_ops);
1537 out:
1538         return err;
1539 }
1540
1541 static void __exit exit_rpcsec_gss(void)
1542 {
1543         gss_svc_shutdown();
1544         rpcauth_unregister(&authgss_ops);
1545 }
1546
1547 MODULE_LICENSE("GPL");
1548 module_init(init_rpcsec_gss)
1549 module_exit(exit_rpcsec_gss)