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   1 /*
   2  * fs/nfs/idmap.c
   3  *
   4  *  UID and GID to name mapping for clients.
   5  *
   6  *  Copyright (c) 2002 The Regents of the University of Michigan.
   7  *  All rights reserved.
   8  *
   9  *  Marius Aamodt Eriksen <marius@umich.edu>
  10  *
  11  *  Redistribution and use in source and binary forms, with or without
  12  *  modification, are permitted provided that the following conditions
  13  *  are met:
  14  *
  15  *  1. Redistributions of source code must retain the above copyright
  16  *     notice, this list of conditions and the following disclaimer.
  17  *  2. Redistributions in binary form must reproduce the above copyright
  18  *     notice, this list of conditions and the following disclaimer in the
  19  *     documentation and/or other materials provided with the distribution.
  20  *  3. Neither the name of the University nor the names of its
  21  *     contributors may be used to endorse or promote products derived
  22  *     from this software without specific prior written permission.
  23  *
  24  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  25  *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  26  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  27  *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  29  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  30  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  31  *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  32  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  33  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  34  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  35  */
  36
  37 #include <linux/module.h>
  38 #include <linux/init.h>
  39 #include <linux/types.h>
  40 #include <linux/slab.h>
  41 #include <linux/socket.h>
  42 #include <linux/in.h>
  43 #include <linux/sched.h>
  44
  45 #include <linux/sunrpc/clnt.h>
  46 #include <linux/workqueue.h>
  47 #include <linux/sunrpc/rpc_pipe_fs.h>
  48
  49 #include <linux/nfs_fs_sb.h>
  50 #include <linux/nfs_fs.h>
  51
  52 #include <linux/nfs_idmap.h>
  53 #include "nfs4_fs.h"
  54
  55 #define IDMAP_HASH_SZ          128
  56
  57 /* Default cache timeout is 10 minutes */
  58 unsigned int nfs_idmap_cache_timeout = 600 * HZ;
  59
  60 struct idmap_hashent {
  61         unsigned long ih_expires;
  62         __u32 ih_id;
  63         int ih_namelen;
  64         char ih_name[IDMAP_NAMESZ];
  65 };
  66
  67 struct idmap_hashtable {
  68         __u8 h_type;
  69         struct idmap_hashent h_entries[IDMAP_HASH_SZ];
  70 };
  71
  72 struct idmap {
  73         char                  idmap_path[48];
  74         struct dentry        *idmap_dentry;
  75         wait_queue_head_t     idmap_wq;
  76         struct idmap_msg      idmap_im;
  77         struct semaphore      idmap_lock;    /* Serializes upcalls */
  78         struct semaphore      idmap_im_lock; /* Protects the hashtable */
  79         struct idmap_hashtable idmap_user_hash;
  80         struct idmap_hashtable idmap_group_hash;
  81 };
  82
  83 static ssize_t   idmap_pipe_upcall(struct file *, struct rpc_pipe_msg *,
  84                      char __user *, size_t);
  85 static ssize_t   idmap_pipe_downcall(struct file *, const char __user *,
  86                      size_t);
  87 static void      idmap_pipe_destroy_msg(struct rpc_pipe_msg *);
  88
  89 static unsigned int fnvhash32(const void *, size_t);
  90
  91 static struct rpc_pipe_ops idmap_upcall_ops = {
  92         .upcall         = idmap_pipe_upcall,
  93         .downcall       = idmap_pipe_downcall,
  94         .destroy_msg    = idmap_pipe_destroy_msg,
  95 };
  96
  97 void
  98 nfs_idmap_new(struct nfs4_client *clp)
  99 {
 100         struct idmap *idmap;
 101
 102         if (clp->cl_idmap != NULL)
 103                 return;
 104         if ((idmap = kmalloc(sizeof(*idmap), GFP_KERNEL)) == NULL)
 105                 return;
 106
 107         memset(idmap, 0, sizeof(*idmap));
 108
 109         snprintf(idmap->idmap_path, sizeof(idmap->idmap_path),
 110             "%s/idmap", clp->cl_rpcclient->cl_pathname);
 111
 112         idmap->idmap_dentry = rpc_mkpipe(idmap->idmap_path,
 113             idmap, &idmap_upcall_ops, 0);
 114         if (IS_ERR(idmap->idmap_dentry)) {
 115                 kfree(idmap);
 116                 return;
 117         }
 118
 119         init_MUTEX(&idmap->idmap_lock);
 120         init_MUTEX(&idmap->idmap_im_lock);
 121         init_waitqueue_head(&idmap->idmap_wq);
 122         idmap->idmap_user_hash.h_type = IDMAP_TYPE_USER;
 123         idmap->idmap_group_hash.h_type = IDMAP_TYPE_GROUP;
 124
 125         clp->cl_idmap = idmap;
 126 }
 127
 128 void
 129 nfs_idmap_delete(struct nfs4_client *clp)
 130 {
 131         struct idmap *idmap = clp->cl_idmap;
 132
 133         if (!idmap)
 134                 return;
 135         rpc_unlink(idmap->idmap_path);
 136         clp->cl_idmap = NULL;
 137         kfree(idmap);
 138 }
 139
 140 /*
 141  * Helper routines for manipulating the hashtable
 142  */
 143 static inline struct idmap_hashent *
 144 idmap_name_hash(struct idmap_hashtable* h, const char *name, size_t len)
 145 {
 146         return &h->h_entries[fnvhash32(name, len) % IDMAP_HASH_SZ];
 147 }
 148
 149 static struct idmap_hashent *
 150 idmap_lookup_name(struct idmap_hashtable *h, const char *name, size_t len)
 151 {
 152         struct idmap_hashent *he = idmap_name_hash(h, name, len);
 153
 154         if (he->ih_namelen != len || memcmp(he->ih_name, name, len) != 0)
 155                 return NULL;
 156         if (time_after(jiffies, he->ih_expires))
 157                 return NULL;
 158         return he;
 159 }
 160
 161 static inline struct idmap_hashent *
 162 idmap_id_hash(struct idmap_hashtable* h, __u32 id)
 163 {
 164         return &h->h_entries[fnvhash32(&id, sizeof(id)) % IDMAP_HASH_SZ];
 165 }
 166
 167 static struct idmap_hashent *
 168 idmap_lookup_id(struct idmap_hashtable *h, __u32 id)
 169 {
 170         struct idmap_hashent *he = idmap_id_hash(h, id);
 171         if (he->ih_id != id || he->ih_namelen == 0)
 172                 return NULL;
 173         if (time_after(jiffies, he->ih_expires))
 174                 return NULL;
 175         return he;
 176 }
 177
 178 /*
 179  * Routines for allocating new entries in the hashtable.
 180  * For now, we just have 1 entry per bucket, so it's all
 181  * pretty trivial.
 182  */
 183 static inline struct idmap_hashent *
 184 idmap_alloc_name(struct idmap_hashtable *h, char *name, unsigned len)
 185 {
 186         return idmap_name_hash(h, name, len);
 187 }
 188
 189 static inline struct idmap_hashent *
 190 idmap_alloc_id(struct idmap_hashtable *h, __u32 id)
 191 {
 192         return idmap_id_hash(h, id);
 193 }
 194
 195 static void
 196 idmap_update_entry(struct idmap_hashent *he, const char *name,
 197                 size_t namelen, __u32 id)
 198 {
 199         he->ih_id = id;
 200         memcpy(he->ih_name, name, namelen);
 201         he->ih_name[namelen] = '\0';
 202         he->ih_namelen = namelen;
 203         he->ih_expires = jiffies + nfs_idmap_cache_timeout;
 204 }
 205
 206 /*
 207  * Name -> ID
 208  */
 209 static int
 210 nfs_idmap_id(struct idmap *idmap, struct idmap_hashtable *h,
 211                 const char *name, size_t namelen, __u32 *id)
 212 {
 213         struct rpc_pipe_msg msg;
 214         struct idmap_msg *im;
 215         struct idmap_hashent *he;
 216         DECLARE_WAITQUEUE(wq, current);
 217         int ret = -EIO;
 218
 219         im = &idmap->idmap_im;
 220
 221         /*
 222          * String sanity checks
 223          * Note that the userland daemon expects NUL terminated strings
 224          */
 225         for (;;) {
 226                 if (namelen == 0)
 227                         return -EINVAL;
 228                 if (name[namelen-1] != '\0')
 229                         break;
 230                 namelen--;
 231         }
 232         if (namelen >= IDMAP_NAMESZ)
 233                 return -EINVAL;
 234
 235         down(&idmap->idmap_lock);
 236         down(&idmap->idmap_im_lock);
 237
 238         he = idmap_lookup_name(h, name, namelen);
 239         if (he != NULL) {
 240                 *id = he->ih_id;
 241                 ret = 0;
 242                 goto out;
 243         }
 244
 245         memset(im, 0, sizeof(*im));
 246         memcpy(im->im_name, name, namelen);
 247
 248         im->im_type = h->h_type;
 249         im->im_conv = IDMAP_CONV_NAMETOID;
 250
 251         memset(&msg, 0, sizeof(msg));
 252         msg.data = im;
 253         msg.len = sizeof(*im);
 254
 255         add_wait_queue(&idmap->idmap_wq, &wq);
 256         if (rpc_queue_upcall(idmap->idmap_dentry->d_inode, &msg) < 0) {
 257                 remove_wait_queue(&idmap->idmap_wq, &wq);
 258                 goto out;
 259         }
 260
 261         set_current_state(TASK_UNINTERRUPTIBLE);
 262         up(&idmap->idmap_im_lock);
 263         schedule();
 264         current->state = TASK_RUNNING;
 265         remove_wait_queue(&idmap->idmap_wq, &wq);
 266         down(&idmap->idmap_im_lock);
 267
 268         if (im->im_status & IDMAP_STATUS_SUCCESS) {
 269                 *id = im->im_id;
 270                 ret = 0;
 271         }
 272
 273  out:
 274         memset(im, 0, sizeof(*im));
 275         up(&idmap->idmap_im_lock);
 276         up(&idmap->idmap_lock);
 277         return (ret);
 278 }
 279
 280 /*
 281  * ID -> Name
 282  */
 283 static int
 284 nfs_idmap_name(struct idmap *idmap, struct idmap_hashtable *h,
 285                 __u32 id, char *name)
 286 {
 287         struct rpc_pipe_msg msg;
 288         struct idmap_msg *im;
 289         struct idmap_hashent *he;
 290         DECLARE_WAITQUEUE(wq, current);
 291         int ret = -EIO;
 292         unsigned int len;
 293
 294         im = &idmap->idmap_im;
 295
 296         down(&idmap->idmap_lock);
 297         down(&idmap->idmap_im_lock);
 298
 299         he = idmap_lookup_id(h, id);
 300         if (he != 0) {
 301                 memcpy(name, he->ih_name, he->ih_namelen);
 302                 ret = he->ih_namelen;
 303                 goto out;
 304         }
 305
 306         memset(im, 0, sizeof(*im));
 307         im->im_type = h->h_type;
 308         im->im_conv = IDMAP_CONV_IDTONAME;
 309         im->im_id = id;
 310
 311         memset(&msg, 0, sizeof(msg));
 312         msg.data = im;
 313         msg.len = sizeof(*im);
 314
 315         add_wait_queue(&idmap->idmap_wq, &wq);
 316
 317         if (rpc_queue_upcall(idmap->idmap_dentry->d_inode, &msg) < 0) {
 318                 remove_wait_queue(&idmap->idmap_wq, &wq);
 319                 goto out;
 320         }
 321
 322         set_current_state(TASK_UNINTERRUPTIBLE);
 323         up(&idmap->idmap_im_lock);
 324         schedule();
 325         current->state = TASK_RUNNING;
 326         remove_wait_queue(&idmap->idmap_wq, &wq);
 327         down(&idmap->idmap_im_lock);
 328
 329         if (im->im_status & IDMAP_STATUS_SUCCESS) {
 330                 if ((len = strnlen(im->im_name, IDMAP_NAMESZ)) == 0)
 331                         goto out;
 332                 memcpy(name, im->im_name, len);
 333                 ret = len;
 334         }
 335
 336  out:
 337         memset(im, 0, sizeof(*im));
 338         up(&idmap->idmap_im_lock);
 339         up(&idmap->idmap_lock);
 340         return ret;
 341 }
 342
 343 /* RPC pipefs upcall/downcall routines */
 344 static ssize_t
 345 idmap_pipe_upcall(struct file *filp, struct rpc_pipe_msg *msg,
 346     char __user *dst, size_t buflen)
 347 {
 348         char *data = (char *)msg->data + msg->copied;
 349         ssize_t mlen = msg->len - msg->copied;
 350         ssize_t left;
 351
 352         if (mlen > buflen)
 353                 mlen = buflen;
 354
 355         left = copy_to_user(dst, data, mlen);
 356         if (left < 0) {
 357                 msg->errno = left;
 358                 return left;
 359         }
 360         mlen -= left;
 361         msg->copied += mlen;
 362         msg->errno = 0;
 363         return mlen;
 364 }
 365
 366 static ssize_t
 367 idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 368 {
 369         struct rpc_inode *rpci = RPC_I(filp->f_dentry->d_inode);
 370         struct idmap *idmap = (struct idmap *)rpci->private;
 371         struct idmap_msg im_in, *im = &idmap->idmap_im;
 372         struct idmap_hashtable *h;
 373         struct idmap_hashent *he = NULL;
 374         int namelen_in;
 375         int ret;
 376
 377         if (mlen != sizeof(im_in))
 378                 return (-ENOSPC);
 379
 380         if (copy_from_user(&im_in, src, mlen) != 0)
 381                 return (-EFAULT);
 382
 383         down(&idmap->idmap_im_lock);
 384
 385         ret = mlen;
 386         im->im_status = im_in.im_status;
 387         /* If we got an error, terminate now, and wake up pending upcalls */
 388         if (!(im_in.im_status & IDMAP_STATUS_SUCCESS)) {
 389                 wake_up(&idmap->idmap_wq);
 390                 goto out;
 391         }
 392
 393         /* Sanity checking of strings */
 394         ret = -EINVAL;
 395         namelen_in = strnlen(im_in.im_name, IDMAP_NAMESZ);
 396         if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ)
 397                 goto out;
 398
 399         switch (im_in.im_type) {
 400                 case IDMAP_TYPE_USER:
 401                         h = &idmap->idmap_user_hash;
 402                         break;
 403                 case IDMAP_TYPE_GROUP:
 404                         h = &idmap->idmap_group_hash;
 405                         break;
 406                 default:
 407                         goto out;
 408         }
 409
 410         switch (im_in.im_conv) {
 411         case IDMAP_CONV_IDTONAME:
 412                 /* Did we match the current upcall? */
 413                 if (im->im_conv == IDMAP_CONV_IDTONAME
 414                                 && im->im_type == im_in.im_type
 415                                 && im->im_id == im_in.im_id) {
 416                         /* Yes: copy string, including the terminating '\0'  */
 417                         memcpy(im->im_name, im_in.im_name, namelen_in);
 418                         im->im_name[namelen_in] = '\0';
 419                         wake_up(&idmap->idmap_wq);
 420                 }
 421                 he = idmap_alloc_id(h, im_in.im_id);
 422                 break;
 423         case IDMAP_CONV_NAMETOID:
 424                 /* Did we match the current upcall? */
 425                 if (im->im_conv == IDMAP_CONV_NAMETOID
 426                                 && im->im_type == im_in.im_type
 427                                 && strnlen(im->im_name, IDMAP_NAMESZ) == namelen_in
 428                                 && memcmp(im->im_name, im_in.im_name, namelen_in) == 0) {
 429                         im->im_id = im_in.im_id;
 430                         wake_up(&idmap->idmap_wq);
 431                 }
 432                 he = idmap_alloc_name(h, im_in.im_name, namelen_in);
 433                 break;
 434         default:
 435                 goto out;
 436         }
 437
 438         /* If the entry is valid, also copy it to the cache */
 439         if (he != NULL)
 440                 idmap_update_entry(he, im_in.im_name, namelen_in, im_in.im_id);
 441         ret = mlen;
 442 out:
 443         up(&idmap->idmap_im_lock);
 444         return ret;
 445 }
 446
 447 static void
 448 idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 449 {
 450         struct idmap_msg *im = msg->data;
 451         struct idmap *idmap = container_of(im, struct idmap, idmap_im);
 452
 453         if (msg->errno >= 0)
 454                 return;
 455         down(&idmap->idmap_im_lock);
 456         im->im_status = IDMAP_STATUS_LOOKUPFAIL;
 457         wake_up(&idmap->idmap_wq);
 458         up(&idmap->idmap_im_lock);
 459 }
 460
 461 /*
 462  * Fowler/Noll/Vo hash
 463  *    http://www.isthe.com/chongo/tech/comp/fnv/
 464  */
 465
 466 #define FNV_P_32 ((unsigned int)0x01000193) /* 16777619 */
 467 #define FNV_1_32 ((unsigned int)0x811c9dc5) /* 2166136261 */
 468
 469 static unsigned int fnvhash32(const void *buf, size_t buflen)
 470 {
 471         const unsigned char *p, *end = (const unsigned char *)buf + buflen;
 472         unsigned int hash = FNV_1_32;
 473
 474         for (p = buf; p < end; p++) {
 475                 hash *= FNV_P_32;
 476                 hash ^= (unsigned int)*p;
 477         }
 478
 479         return (hash);
 480 }
 481
 482 int nfs_map_name_to_uid(struct nfs4_client *clp, const char *name, size_t namelen, __u32 *uid)
 483 {
 484         struct idmap *idmap = clp->cl_idmap;
 485
 486         return nfs_idmap_id(idmap, &idmap->idmap_user_hash, name, namelen, uid);
 487 }
 488
 489 int nfs_map_group_to_gid(struct nfs4_client *clp, const char *name, size_t namelen, __u32 *uid)
 490 {
 491         struct idmap *idmap = clp->cl_idmap;
 492
 493         return nfs_idmap_id(idmap, &idmap->idmap_group_hash, name, namelen, uid);
 494 }
 495
 496 int nfs_map_uid_to_name(struct nfs4_client *clp, __u32 uid, char *buf)
 497 {
 498         struct idmap *idmap = clp->cl_idmap;
 499
 500         return nfs_idmap_name(idmap, &idmap->idmap_user_hash, uid, buf);
 501 }
 502 int nfs_map_gid_to_group(struct nfs4_client *clp, __u32 uid, char *buf)
 503 {
 504         struct idmap *idmap = clp->cl_idmap;
 505
 506         return nfs_idmap_name(idmap, &idmap->idmap_group_hash, uid, buf);
 507 }
 508