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 struct idmap_hashent {
  58         __u32 ih_id;
  59         int ih_namelen;
  60         char ih_name[IDMAP_NAMESZ];
  61 };
  62
  63 struct idmap_hashtable {
  64         __u8 h_type;
  65         struct idmap_hashent h_entries[IDMAP_HASH_SZ];
  66 };
  67
  68 struct idmap {
  69         char                  idmap_path[48];
  70         struct dentry        *idmap_dentry;
  71         wait_queue_head_t     idmap_wq;
  72         struct idmap_msg      idmap_im;
  73         struct semaphore      idmap_lock;    /* Serializes upcalls */
  74         struct semaphore      idmap_im_lock; /* Protects the hashtable */
  75         struct idmap_hashtable idmap_user_hash;
  76         struct idmap_hashtable idmap_group_hash;
  77 };
  78
  79 static ssize_t   idmap_pipe_upcall(struct file *, struct rpc_pipe_msg *,
  80                      char __user *, size_t);
  81 static ssize_t   idmap_pipe_downcall(struct file *, const char __user *,
  82                      size_t);
  83 static void      idmap_pipe_destroy_msg(struct rpc_pipe_msg *);
  84
  85 static unsigned int fnvhash32(const void *, size_t);
  86
  87 static struct rpc_pipe_ops idmap_upcall_ops = {
  88         .upcall         = idmap_pipe_upcall,
  89         .downcall       = idmap_pipe_downcall,
  90         .destroy_msg    = idmap_pipe_destroy_msg,
  91 };
  92
  93 void
  94 nfs_idmap_new(struct nfs4_client *clp)
  95 {
  96         struct idmap *idmap;
  97
  98         if (clp->cl_idmap != NULL)
  99                 return;
 100         if ((idmap = kmalloc(sizeof(*idmap), GFP_KERNEL)) == NULL)
 101                 return;
 102
 103         memset(idmap, 0, sizeof(*idmap));
 104
 105         snprintf(idmap->idmap_path, sizeof(idmap->idmap_path),
 106             "%s/idmap", clp->cl_rpcclient->cl_pathname);
 107
 108         idmap->idmap_dentry = rpc_mkpipe(idmap->idmap_path,
 109             idmap, &idmap_upcall_ops, 0);
 110         if (IS_ERR(idmap->idmap_dentry)) {
 111                 kfree(idmap);
 112                 return;
 113         }
 114
 115         init_MUTEX(&idmap->idmap_lock);
 116         init_MUTEX(&idmap->idmap_im_lock);
 117         init_waitqueue_head(&idmap->idmap_wq);
 118         idmap->idmap_user_hash.h_type = IDMAP_TYPE_USER;
 119         idmap->idmap_group_hash.h_type = IDMAP_TYPE_GROUP;
 120
 121         clp->cl_idmap = idmap;
 122 }
 123
 124 void
 125 nfs_idmap_delete(struct nfs4_client *clp)
 126 {
 127         struct idmap *idmap = clp->cl_idmap;
 128
 129         if (!idmap)
 130                 return;
 131         rpc_unlink(idmap->idmap_path);
 132         clp->cl_idmap = NULL;
 133         kfree(idmap);
 134 }
 135
 136 /*
 137  * Helper routines for manipulating the hashtable
 138  */
 139 static inline struct idmap_hashent *
 140 idmap_name_hash(struct idmap_hashtable* h, const char *name, size_t len)
 141 {
 142         return &h->h_entries[fnvhash32(name, len) % IDMAP_HASH_SZ];
 143 }
 144
 145 static struct idmap_hashent *
 146 idmap_lookup_name(struct idmap_hashtable *h, const char *name, size_t len)
 147 {
 148         struct idmap_hashent *he = idmap_name_hash(h, name, len);
 149
 150         if (he->ih_namelen != len || memcmp(he->ih_name, name, len) != 0)
 151                 return NULL;
 152         return he;
 153 }
 154
 155 static inline struct idmap_hashent *
 156 idmap_id_hash(struct idmap_hashtable* h, __u32 id)
 157 {
 158         return &h->h_entries[fnvhash32(&id, sizeof(id)) % IDMAP_HASH_SZ];
 159 }
 160
 161 static struct idmap_hashent *
 162 idmap_lookup_id(struct idmap_hashtable *h, __u32 id)
 163 {
 164         struct idmap_hashent *he = idmap_id_hash(h, id);
 165         if (he->ih_id != id || he->ih_namelen == 0)
 166                 return NULL;
 167         return he;
 168 }
 169
 170 /*
 171  * Routines for allocating new entries in the hashtable.
 172  * For now, we just have 1 entry per bucket, so it's all
 173  * pretty trivial.
 174  */
 175 static inline struct idmap_hashent *
 176 idmap_alloc_name(struct idmap_hashtable *h, char *name, unsigned len)
 177 {
 178         return idmap_name_hash(h, name, len);
 179 }
 180
 181 static inline struct idmap_hashent *
 182 idmap_alloc_id(struct idmap_hashtable *h, __u32 id)
 183 {
 184         return idmap_id_hash(h, id);
 185 }
 186
 187 static void
 188 idmap_update_entry(struct idmap_hashent *he, const char *name,
 189                 size_t namelen, __u32 id)
 190 {
 191         he->ih_id = id;
 192         memcpy(he->ih_name, name, namelen);
 193         he->ih_name[namelen] = '\0';
 194         he->ih_namelen = namelen;
 195 }
 196
 197 /*
 198  * Name -> ID
 199  */
 200 static int
 201 nfs_idmap_id(struct idmap *idmap, struct idmap_hashtable *h,
 202                 const char *name, size_t namelen, __u32 *id)
 203 {
 204         struct rpc_pipe_msg msg;
 205         struct idmap_msg *im;
 206         struct idmap_hashent *he;
 207         DECLARE_WAITQUEUE(wq, current);
 208         int ret = -EIO;
 209
 210         im = &idmap->idmap_im;
 211
 212         /*
 213          * String sanity checks
 214          * Note that the userland daemon expects NUL terminated strings
 215          */
 216         for (;;) {
 217                 if (namelen == 0)
 218                         return -EINVAL;
 219                 if (name[namelen-1] != '\0')
 220                         break;
 221                 namelen--;
 222         }
 223         if (namelen >= IDMAP_NAMESZ)
 224                 return -EINVAL;
 225
 226         down(&idmap->idmap_lock);
 227         down(&idmap->idmap_im_lock);
 228
 229         he = idmap_lookup_name(h, name, namelen);
 230         if (he != NULL) {
 231                 *id = he->ih_id;
 232                 ret = 0;
 233                 goto out;
 234         }
 235
 236         memset(im, 0, sizeof(*im));
 237         memcpy(im->im_name, name, namelen);
 238
 239         im->im_type = h->h_type;
 240         im->im_conv = IDMAP_CONV_NAMETOID;
 241
 242         memset(&msg, 0, sizeof(msg));
 243         msg.data = im;
 244         msg.len = sizeof(*im);
 245
 246         add_wait_queue(&idmap->idmap_wq, &wq);
 247         if (rpc_queue_upcall(idmap->idmap_dentry->d_inode, &msg) < 0) {
 248                 remove_wait_queue(&idmap->idmap_wq, &wq);
 249                 goto out;
 250         }
 251
 252         set_current_state(TASK_UNINTERRUPTIBLE);
 253         up(&idmap->idmap_im_lock);
 254         schedule();
 255         current->state = TASK_RUNNING;
 256         remove_wait_queue(&idmap->idmap_wq, &wq);
 257         down(&idmap->idmap_im_lock);
 258
 259         if (im->im_status & IDMAP_STATUS_SUCCESS) {
 260                 *id = im->im_id;
 261                 ret = 0;
 262         }
 263
 264  out:
 265         memset(im, 0, sizeof(*im));
 266         up(&idmap->idmap_im_lock);
 267         up(&idmap->idmap_lock);
 268         return (ret);
 269 }
 270
 271 /*
 272  * ID -> Name
 273  */
 274 static int
 275 nfs_idmap_name(struct idmap *idmap, struct idmap_hashtable *h,
 276                 __u32 id, char *name)
 277 {
 278         struct rpc_pipe_msg msg;
 279         struct idmap_msg *im;
 280         struct idmap_hashent *he;
 281         DECLARE_WAITQUEUE(wq, current);
 282         int ret = -EIO;
 283         unsigned int len;
 284
 285         im = &idmap->idmap_im;
 286
 287         down(&idmap->idmap_lock);
 288         down(&idmap->idmap_im_lock);
 289
 290         he = idmap_lookup_id(h, id);
 291         if (he != 0) {
 292                 memcpy(name, he->ih_name, he->ih_namelen);
 293                 ret = he->ih_namelen;
 294                 goto out;
 295         }
 296
 297         memset(im, 0, sizeof(*im));
 298         im->im_type = h->h_type;
 299         im->im_conv = IDMAP_CONV_IDTONAME;
 300         im->im_id = id;
 301
 302         memset(&msg, 0, sizeof(msg));
 303         msg.data = im;
 304         msg.len = sizeof(*im);
 305
 306         add_wait_queue(&idmap->idmap_wq, &wq);
 307
 308         if (rpc_queue_upcall(idmap->idmap_dentry->d_inode, &msg) < 0) {
 309                 remove_wait_queue(&idmap->idmap_wq, &wq);
 310                 goto out;
 311         }
 312
 313         set_current_state(TASK_UNINTERRUPTIBLE);
 314         up(&idmap->idmap_im_lock);
 315         schedule();
 316         current->state = TASK_RUNNING;
 317         remove_wait_queue(&idmap->idmap_wq, &wq);
 318         down(&idmap->idmap_im_lock);
 319
 320         if (im->im_status & IDMAP_STATUS_SUCCESS) {
 321                 if ((len = strnlen(im->im_name, IDMAP_NAMESZ)) == 0)
 322                         goto out;
 323                 memcpy(name, im->im_name, len);
 324                 ret = len;
 325         }
 326
 327  out:
 328         memset(im, 0, sizeof(*im));
 329         up(&idmap->idmap_im_lock);
 330         up(&idmap->idmap_lock);
 331         return ret;
 332 }
 333
 334 /* RPC pipefs upcall/downcall routines */
 335 static ssize_t
 336 idmap_pipe_upcall(struct file *filp, struct rpc_pipe_msg *msg,
 337     char __user *dst, size_t buflen)
 338 {
 339         char *data = (char *)msg->data + msg->copied;
 340         ssize_t mlen = msg->len - msg->copied;
 341         ssize_t left;
 342
 343         if (mlen > buflen)
 344                 mlen = buflen;
 345
 346         left = copy_to_user(dst, data, mlen);
 347         if (left < 0) {
 348                 msg->errno = left;
 349                 return left;
 350         }
 351         mlen -= left;
 352         msg->copied += mlen;
 353         msg->errno = 0;
 354         return mlen;
 355 }
 356
 357 static ssize_t
 358 idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 359 {
 360         struct rpc_inode *rpci = RPC_I(filp->f_dentry->d_inode);
 361         struct idmap *idmap = (struct idmap *)rpci->private;
 362         struct idmap_msg im_in, *im = &idmap->idmap_im;
 363         struct idmap_hashtable *h;
 364         struct idmap_hashent *he = NULL;
 365         int namelen_in;
 366         int ret;
 367
 368         if (mlen != sizeof(im_in))
 369                 return (-ENOSPC);
 370
 371         if (copy_from_user(&im_in, src, mlen) != 0)
 372                 return (-EFAULT);
 373
 374         down(&idmap->idmap_im_lock);
 375
 376         ret = mlen;
 377         im->im_status = im_in.im_status;
 378         /* If we got an error, terminate now, and wake up pending upcalls */
 379         if (!(im_in.im_status & IDMAP_STATUS_SUCCESS)) {
 380                 wake_up(&idmap->idmap_wq);
 381                 goto out;
 382         }
 383
 384         /* Sanity checking of strings */
 385         ret = -EINVAL;
 386         namelen_in = strnlen(im_in.im_name, IDMAP_NAMESZ);
 387         if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ)
 388                 goto out;
 389
 390         switch (im_in.im_type) {
 391                 case IDMAP_TYPE_USER:
 392                         h = &idmap->idmap_user_hash;
 393                         break;
 394                 case IDMAP_TYPE_GROUP:
 395                         h = &idmap->idmap_group_hash;
 396                         break;
 397                 default:
 398                         goto out;
 399         }
 400
 401         switch (im_in.im_conv) {
 402         case IDMAP_CONV_IDTONAME:
 403                 /* Did we match the current upcall? */
 404                 if (im->im_conv == IDMAP_CONV_IDTONAME
 405                                 && im->im_type == im_in.im_type
 406                                 && im->im_id == im_in.im_id) {
 407                         /* Yes: copy string, including the terminating '\0'  */
 408                         memcpy(im->im_name, im_in.im_name, namelen_in);
 409                         im->im_name[namelen_in] = '\0';
 410                         wake_up(&idmap->idmap_wq);
 411                 }
 412                 he = idmap_alloc_id(h, im_in.im_id);
 413                 break;
 414         case IDMAP_CONV_NAMETOID:
 415                 /* Did we match the current upcall? */
 416                 if (im->im_conv == IDMAP_CONV_NAMETOID
 417                                 && im->im_type == im_in.im_type
 418                                 && strnlen(im->im_name, IDMAP_NAMESZ) == namelen_in
 419                                 && memcmp(im->im_name, im_in.im_name, namelen_in) == 0) {
 420                         im->im_id = im_in.im_id;
 421                         wake_up(&idmap->idmap_wq);
 422                 }
 423                 he = idmap_alloc_name(h, im_in.im_name, namelen_in);
 424                 break;
 425         default:
 426                 goto out;
 427         }
 428
 429         /* If the entry is valid, also copy it to the cache */
 430         if (he != NULL)
 431                 idmap_update_entry(he, im_in.im_name, namelen_in, im_in.im_id);
 432         ret = mlen;
 433 out:
 434         up(&idmap->idmap_im_lock);
 435         return ret;
 436 }
 437
 438 static void
 439 idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 440 {
 441         struct idmap_msg *im = msg->data;
 442         struct idmap *idmap = container_of(im, struct idmap, idmap_im);
 443
 444         if (msg->errno >= 0)
 445                 return;
 446         down(&idmap->idmap_im_lock);
 447         im->im_status = IDMAP_STATUS_LOOKUPFAIL;
 448         wake_up(&idmap->idmap_wq);
 449         up(&idmap->idmap_im_lock);
 450 }
 451
 452 /*
 453  * Fowler/Noll/Vo hash
 454  *    http://www.isthe.com/chongo/tech/comp/fnv/
 455  */
 456
 457 #define FNV_P_32 ((unsigned int)0x01000193) /* 16777619 */
 458 #define FNV_1_32 ((unsigned int)0x811c9dc5) /* 2166136261 */
 459
 460 static unsigned int fnvhash32(const void *buf, size_t buflen)
 461 {
 462         const unsigned char *p, *end = (const unsigned char *)buf + buflen;
 463         unsigned int hash = FNV_1_32;
 464
 465         for (p = buf; p < end; p++) {
 466                 hash *= FNV_P_32;
 467                 hash ^= (unsigned int)*p;
 468         }
 469
 470         return (hash);
 471 }
 472
 473 int nfs_map_name_to_uid(struct nfs4_client *clp, const char *name, size_t namelen, __u32 *uid)
 474 {
 475         struct idmap *idmap = clp->cl_idmap;
 476
 477         return nfs_idmap_id(idmap, &idmap->idmap_user_hash, name, namelen, uid);
 478 }
 479
 480 int nfs_map_group_to_gid(struct nfs4_client *clp, const char *name, size_t namelen, __u32 *uid)
 481 {
 482         struct idmap *idmap = clp->cl_idmap;
 483
 484         return nfs_idmap_id(idmap, &idmap->idmap_group_hash, name, namelen, uid);
 485 }
 486
 487 int nfs_map_uid_to_name(struct nfs4_client *clp, __u32 uid, char *buf)
 488 {
 489         struct idmap *idmap = clp->cl_idmap;
 490
 491         return nfs_idmap_name(idmap, &idmap->idmap_user_hash, uid, buf);
 492 }
 493 int nfs_map_gid_to_group(struct nfs4_client *clp, __u32 uid, char *buf)
 494 {
 495         struct idmap *idmap = clp->cl_idmap;
 496
 497         return nfs_idmap_name(idmap, &idmap->idmap_group_hash, uid, buf);
 498 }
 499