err.no Git - linux-2.6/blob - fs/nfs/idmap.c

   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         dput(idmap->idmap_dentry);
 136         idmap->idmap_dentry = NULL;
 137         rpc_unlink(idmap->idmap_path);
 138         clp->cl_idmap = NULL;
 139         kfree(idmap);
 140 }
 141
 142 /*
 143  * Helper routines for manipulating the hashtable
 144  */
 145 static inline struct idmap_hashent *
 146 idmap_name_hash(struct idmap_hashtable* h, const char *name, size_t len)
 147 {
 148         return &h->h_entries[fnvhash32(name, len) % IDMAP_HASH_SZ];
 149 }
 150
 151 static struct idmap_hashent *
 152 idmap_lookup_name(struct idmap_hashtable *h, const char *name, size_t len)
 153 {
 154         struct idmap_hashent *he = idmap_name_hash(h, name, len);
 155
 156         if (he->ih_namelen != len || memcmp(he->ih_name, name, len) != 0)
 157                 return NULL;
 158         if (time_after(jiffies, he->ih_expires))
 159                 return NULL;
 160         return he;
 161 }
 162
 163 static inline struct idmap_hashent *
 164 idmap_id_hash(struct idmap_hashtable* h, __u32 id)
 165 {
 166         return &h->h_entries[fnvhash32(&id, sizeof(id)) % IDMAP_HASH_SZ];
 167 }
 168
 169 static struct idmap_hashent *
 170 idmap_lookup_id(struct idmap_hashtable *h, __u32 id)
 171 {
 172         struct idmap_hashent *he = idmap_id_hash(h, id);
 173         if (he->ih_id != id || he->ih_namelen == 0)
 174                 return NULL;
 175         if (time_after(jiffies, he->ih_expires))
 176                 return NULL;
 177         return he;
 178 }
 179
 180 /*
 181  * Routines for allocating new entries in the hashtable.
 182  * For now, we just have 1 entry per bucket, so it's all
 183  * pretty trivial.
 184  */
 185 static inline struct idmap_hashent *
 186 idmap_alloc_name(struct idmap_hashtable *h, char *name, unsigned len)
 187 {
 188         return idmap_name_hash(h, name, len);
 189 }
 190
 191 static inline struct idmap_hashent *
 192 idmap_alloc_id(struct idmap_hashtable *h, __u32 id)
 193 {
 194         return idmap_id_hash(h, id);
 195 }
 196
 197 static void
 198 idmap_update_entry(struct idmap_hashent *he, const char *name,
 199                 size_t namelen, __u32 id)
 200 {
 201         he->ih_id = id;
 202         memcpy(he->ih_name, name, namelen);
 203         he->ih_name[namelen] = '\0';
 204         he->ih_namelen = namelen;
 205         he->ih_expires = jiffies + nfs_idmap_cache_timeout;
 206 }
 207
 208 /*
 209  * Name -> ID
 210  */
 211 static int
 212 nfs_idmap_id(struct idmap *idmap, struct idmap_hashtable *h,
 213                 const char *name, size_t namelen, __u32 *id)
 214 {
 215         struct rpc_pipe_msg msg;
 216         struct idmap_msg *im;
 217         struct idmap_hashent *he;
 218         DECLARE_WAITQUEUE(wq, current);
 219         int ret = -EIO;
 220
 221         im = &idmap->idmap_im;
 222
 223         /*
 224          * String sanity checks
 225          * Note that the userland daemon expects NUL terminated strings
 226          */
 227         for (;;) {
 228                 if (namelen == 0)
 229                         return -EINVAL;
 230                 if (name[namelen-1] != '\0')
 231                         break;
 232                 namelen--;
 233         }
 234         if (namelen >= IDMAP_NAMESZ)
 235                 return -EINVAL;
 236
 237         down(&idmap->idmap_lock);
 238         down(&idmap->idmap_im_lock);
 239
 240         he = idmap_lookup_name(h, name, namelen);
 241         if (he != NULL) {
 242                 *id = he->ih_id;
 243                 ret = 0;
 244                 goto out;
 245         }
 246
 247         memset(im, 0, sizeof(*im));
 248         memcpy(im->im_name, name, namelen);
 249
 250         im->im_type = h->h_type;
 251         im->im_conv = IDMAP_CONV_NAMETOID;
 252
 253         memset(&msg, 0, sizeof(msg));
 254         msg.data = im;
 255         msg.len = sizeof(*im);
 256
 257         add_wait_queue(&idmap->idmap_wq, &wq);
 258         if (rpc_queue_upcall(idmap->idmap_dentry->d_inode, &msg) < 0) {
 259                 remove_wait_queue(&idmap->idmap_wq, &wq);
 260                 goto out;
 261         }
 262
 263         set_current_state(TASK_UNINTERRUPTIBLE);
 264         up(&idmap->idmap_im_lock);
 265         schedule();
 266         current->state = TASK_RUNNING;
 267         remove_wait_queue(&idmap->idmap_wq, &wq);
 268         down(&idmap->idmap_im_lock);
 269
 270         if (im->im_status & IDMAP_STATUS_SUCCESS) {
 271                 *id = im->im_id;
 272                 ret = 0;
 273         }
 274
 275  out:
 276         memset(im, 0, sizeof(*im));
 277         up(&idmap->idmap_im_lock);
 278         up(&idmap->idmap_lock);
 279         return (ret);
 280 }
 281
 282 /*
 283  * ID -> Name
 284  */
 285 static int
 286 nfs_idmap_name(struct idmap *idmap, struct idmap_hashtable *h,
 287                 __u32 id, char *name)
 288 {
 289         struct rpc_pipe_msg msg;
 290         struct idmap_msg *im;
 291         struct idmap_hashent *he;
 292         DECLARE_WAITQUEUE(wq, current);
 293         int ret = -EIO;
 294         unsigned int len;
 295
 296         im = &idmap->idmap_im;
 297
 298         down(&idmap->idmap_lock);
 299         down(&idmap->idmap_im_lock);
 300
 301         he = idmap_lookup_id(h, id);
 302         if (he != 0) {
 303                 memcpy(name, he->ih_name, he->ih_namelen);
 304                 ret = he->ih_namelen;
 305                 goto out;
 306         }
 307
 308         memset(im, 0, sizeof(*im));
 309         im->im_type = h->h_type;
 310         im->im_conv = IDMAP_CONV_IDTONAME;
 311         im->im_id = id;
 312
 313         memset(&msg, 0, sizeof(msg));
 314         msg.data = im;
 315         msg.len = sizeof(*im);
 316
 317         add_wait_queue(&idmap->idmap_wq, &wq);
 318
 319         if (rpc_queue_upcall(idmap->idmap_dentry->d_inode, &msg) < 0) {
 320                 remove_wait_queue(&idmap->idmap_wq, &wq);
 321                 goto out;
 322         }
 323
 324         set_current_state(TASK_UNINTERRUPTIBLE);
 325         up(&idmap->idmap_im_lock);
 326         schedule();
 327         current->state = TASK_RUNNING;
 328         remove_wait_queue(&idmap->idmap_wq, &wq);
 329         down(&idmap->idmap_im_lock);
 330
 331         if (im->im_status & IDMAP_STATUS_SUCCESS) {
 332                 if ((len = strnlen(im->im_name, IDMAP_NAMESZ)) == 0)
 333                         goto out;
 334                 memcpy(name, im->im_name, len);
 335                 ret = len;
 336         }
 337
 338  out:
 339         memset(im, 0, sizeof(*im));
 340         up(&idmap->idmap_im_lock);
 341         up(&idmap->idmap_lock);
 342         return ret;
 343 }
 344
 345 /* RPC pipefs upcall/downcall routines */
 346 static ssize_t
 347 idmap_pipe_upcall(struct file *filp, struct rpc_pipe_msg *msg,
 348     char __user *dst, size_t buflen)
 349 {
 350         char *data = (char *)msg->data + msg->copied;
 351         ssize_t mlen = msg->len - msg->copied;
 352         ssize_t left;
 353
 354         if (mlen > buflen)
 355                 mlen = buflen;
 356
 357         left = copy_to_user(dst, data, mlen);
 358         if (left < 0) {
 359                 msg->errno = left;
 360                 return left;
 361         }
 362         mlen -= left;
 363         msg->copied += mlen;
 364         msg->errno = 0;
 365         return mlen;
 366 }
 367
 368 static ssize_t
 369 idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 370 {
 371         struct rpc_inode *rpci = RPC_I(filp->f_dentry->d_inode);
 372         struct idmap *idmap = (struct idmap *)rpci->private;
 373         struct idmap_msg im_in, *im = &idmap->idmap_im;
 374         struct idmap_hashtable *h;
 375         struct idmap_hashent *he = NULL;
 376         int namelen_in;
 377         int ret;
 378
 379         if (mlen != sizeof(im_in))
 380                 return (-ENOSPC);
 381
 382         if (copy_from_user(&im_in, src, mlen) != 0)
 383                 return (-EFAULT);
 384
 385         down(&idmap->idmap_im_lock);
 386
 387         ret = mlen;
 388         im->im_status = im_in.im_status;
 389         /* If we got an error, terminate now, and wake up pending upcalls */
 390         if (!(im_in.im_status & IDMAP_STATUS_SUCCESS)) {
 391                 wake_up(&idmap->idmap_wq);
 392                 goto out;
 393         }
 394
 395         /* Sanity checking of strings */
 396         ret = -EINVAL;
 397         namelen_in = strnlen(im_in.im_name, IDMAP_NAMESZ);
 398         if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ)
 399                 goto out;
 400
 401         switch (im_in.im_type) {
 402                 case IDMAP_TYPE_USER:
 403                         h = &idmap->idmap_user_hash;
 404                         break;
 405                 case IDMAP_TYPE_GROUP:
 406                         h = &idmap->idmap_group_hash;
 407                         break;
 408                 default:
 409                         goto out;
 410         }
 411
 412         switch (im_in.im_conv) {
 413         case IDMAP_CONV_IDTONAME:
 414                 /* Did we match the current upcall? */
 415                 if (im->im_conv == IDMAP_CONV_IDTONAME
 416                                 && im->im_type == im_in.im_type
 417                                 && im->im_id == im_in.im_id) {
 418                         /* Yes: copy string, including the terminating '\0'  */
 419                         memcpy(im->im_name, im_in.im_name, namelen_in);
 420                         im->im_name[namelen_in] = '\0';
 421                         wake_up(&idmap->idmap_wq);
 422                 }
 423                 he = idmap_alloc_id(h, im_in.im_id);
 424                 break;
 425         case IDMAP_CONV_NAMETOID:
 426                 /* Did we match the current upcall? */
 427                 if (im->im_conv == IDMAP_CONV_NAMETOID
 428                                 && im->im_type == im_in.im_type
 429                                 && strnlen(im->im_name, IDMAP_NAMESZ) == namelen_in
 430                                 && memcmp(im->im_name, im_in.im_name, namelen_in) == 0) {
 431                         im->im_id = im_in.im_id;
 432                         wake_up(&idmap->idmap_wq);
 433                 }
 434                 he = idmap_alloc_name(h, im_in.im_name, namelen_in);
 435                 break;
 436         default:
 437                 goto out;
 438         }
 439
 440         /* If the entry is valid, also copy it to the cache */
 441         if (he != NULL)
 442                 idmap_update_entry(he, im_in.im_name, namelen_in, im_in.im_id);
 443         ret = mlen;
 444 out:
 445         up(&idmap->idmap_im_lock);
 446         return ret;
 447 }
 448
 449 static void
 450 idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 451 {
 452         struct idmap_msg *im = msg->data;
 453         struct idmap *idmap = container_of(im, struct idmap, idmap_im);
 454
 455         if (msg->errno >= 0)
 456                 return;
 457         down(&idmap->idmap_im_lock);
 458         im->im_status = IDMAP_STATUS_LOOKUPFAIL;
 459         wake_up(&idmap->idmap_wq);
 460         up(&idmap->idmap_im_lock);
 461 }
 462
 463 /*
 464  * Fowler/Noll/Vo hash
 465  *    http://www.isthe.com/chongo/tech/comp/fnv/
 466  */
 467
 468 #define FNV_P_32 ((unsigned int)0x01000193) /* 16777619 */
 469 #define FNV_1_32 ((unsigned int)0x811c9dc5) /* 2166136261 */
 470
 471 static unsigned int fnvhash32(const void *buf, size_t buflen)
 472 {
 473         const unsigned char *p, *end = (const unsigned char *)buf + buflen;
 474         unsigned int hash = FNV_1_32;
 475
 476         for (p = buf; p < end; p++) {
 477                 hash *= FNV_P_32;
 478                 hash ^= (unsigned int)*p;
 479         }
 480
 481         return (hash);
 482 }
 483
 484 int nfs_map_name_to_uid(struct nfs4_client *clp, const char *name, size_t namelen, __u32 *uid)
 485 {
 486         struct idmap *idmap = clp->cl_idmap;
 487
 488         return nfs_idmap_id(idmap, &idmap->idmap_user_hash, name, namelen, uid);
 489 }
 490
 491 int nfs_map_group_to_gid(struct nfs4_client *clp, const char *name, size_t namelen, __u32 *uid)
 492 {
 493         struct idmap *idmap = clp->cl_idmap;
 494
 495         return nfs_idmap_id(idmap, &idmap->idmap_group_hash, name, namelen, uid);
 496 }
 497
 498 int nfs_map_uid_to_name(struct nfs4_client *clp, __u32 uid, char *buf)
 499 {
 500         struct idmap *idmap = clp->cl_idmap;
 501
 502         return nfs_idmap_name(idmap, &idmap->idmap_user_hash, uid, buf);
 503 }
 504 int nfs_map_gid_to_group(struct nfs4_client *clp, __u32 uid, char *buf)
 505 {
 506         struct idmap *idmap = clp->cl_idmap;
 507
 508         return nfs_idmap_name(idmap, &idmap->idmap_group_hash, uid, buf);
 509 }
 510