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
  54 #define IDMAP_HASH_SZ          128
  55
  56 struct idmap_hashent {
  57         __u32 ih_id;
  58         int ih_namelen;
  59         char ih_name[IDMAP_NAMESZ];
  60 };
  61
  62 struct idmap_hashtable {
  63         __u8 h_type;
  64         struct idmap_hashent h_entries[IDMAP_HASH_SZ];
  65 };
  66
  67 struct idmap {
  68         char                  idmap_path[48];
  69         struct dentry        *idmap_dentry;
  70         wait_queue_head_t     idmap_wq;
  71         struct idmap_msg      idmap_im;
  72         struct semaphore      idmap_lock;    /* Serializes upcalls */
  73         struct semaphore      idmap_im_lock; /* Protects the hashtable */
  74         struct idmap_hashtable idmap_user_hash;
  75         struct idmap_hashtable idmap_group_hash;
  76 };
  77
  78 static ssize_t   idmap_pipe_upcall(struct file *, struct rpc_pipe_msg *, char *,
  79                      size_t);
  80 static ssize_t   idmap_pipe_downcall(struct file *, const char *, size_t);
  81 void             idmap_pipe_destroy_msg(struct rpc_pipe_msg *);
  82
  83 static unsigned int fnvhash32(const void *, size_t);
  84
  85 static struct rpc_pipe_ops idmap_upcall_ops = {
  86         .upcall         = idmap_pipe_upcall,
  87         .downcall       = idmap_pipe_downcall,
  88         .destroy_msg    = idmap_pipe_destroy_msg,
  89 };
  90
  91 void
  92 nfs_idmap_new(struct nfs4_client *clp)
  93 {
  94         struct idmap *idmap;
  95
  96         if (clp->cl_idmap != NULL)
  97                 return;
  98         if ((idmap = kmalloc(sizeof(*idmap), GFP_KERNEL)) == NULL)
  99                 return;
 100
 101         memset(idmap, 0, sizeof(*idmap));
 102
 103         snprintf(idmap->idmap_path, sizeof(idmap->idmap_path),
 104             "%s/idmap", clp->cl_rpcclient->cl_pathname);
 105
 106         idmap->idmap_dentry = rpc_mkpipe(idmap->idmap_path,
 107             idmap, &idmap_upcall_ops, 0);
 108         if (IS_ERR(idmap->idmap_dentry)) {
 109                 kfree(idmap);
 110                 return;
 111         }
 112
 113         init_MUTEX(&idmap->idmap_lock);
 114         init_MUTEX(&idmap->idmap_im_lock);
 115         init_waitqueue_head(&idmap->idmap_wq);
 116         idmap->idmap_user_hash.h_type = IDMAP_TYPE_USER;
 117         idmap->idmap_group_hash.h_type = IDMAP_TYPE_GROUP;
 118
 119         clp->cl_idmap = idmap;
 120 }
 121
 122 void
 123 nfs_idmap_delete(struct nfs4_client *clp)
 124 {
 125         struct idmap *idmap = clp->cl_idmap;
 126
 127         if (!idmap)
 128                 return;
 129         rpc_unlink(idmap->idmap_path);
 130         clp->cl_idmap = NULL;
 131         kfree(idmap);
 132 }
 133
 134 /*
 135  * Helper routines for manipulating the hashtable
 136  */
 137 static inline struct idmap_hashent *
 138 idmap_name_hash(struct idmap_hashtable* h, const char *name, size_t len)
 139 {
 140         return &h->h_entries[fnvhash32(name, len) % IDMAP_HASH_SZ];
 141 }
 142
 143 static struct idmap_hashent *
 144 idmap_lookup_name(struct idmap_hashtable *h, const char *name, size_t len)
 145 {
 146         struct idmap_hashent *he = idmap_name_hash(h, name, len);
 147
 148         if (he->ih_namelen != len || memcmp(he->ih_name, name, len) != 0)
 149                 return NULL;
 150         return he;
 151 }
 152
 153 static inline struct idmap_hashent *
 154 idmap_id_hash(struct idmap_hashtable* h, __u32 id)
 155 {
 156         return &h->h_entries[fnvhash32(&id, sizeof(id)) % IDMAP_HASH_SZ];
 157 }
 158
 159 static struct idmap_hashent *
 160 idmap_lookup_id(struct idmap_hashtable *h, __u32 id)
 161 {
 162         struct idmap_hashent *he = idmap_id_hash(h, id);
 163         if (he->ih_id != id || he->ih_namelen == 0)
 164                 return NULL;
 165         return he;
 166 }
 167
 168 /*
 169  * Routines for allocating new entries in the hashtable.
 170  * For now, we just have 1 entry per bucket, so it's all
 171  * pretty trivial.
 172  */
 173 static inline struct idmap_hashent *
 174 idmap_alloc_name(struct idmap_hashtable *h, char *name, unsigned len)
 175 {
 176         return idmap_name_hash(h, name, len);
 177 }
 178
 179 static inline struct idmap_hashent *
 180 idmap_alloc_id(struct idmap_hashtable *h, __u32 id)
 181 {
 182         return idmap_id_hash(h, id);
 183 }
 184
 185 static void
 186 idmap_update_entry(struct idmap_hashent *he, const char *name,
 187                 size_t namelen, __u32 id)
 188 {
 189         he->ih_id = id;
 190         memcpy(he->ih_name, name, namelen);
 191         he->ih_name[namelen] = '\0';
 192         he->ih_namelen = namelen;
 193 }
 194
 195 /*
 196  * Name -> ID
 197  */
 198 static int
 199 nfs_idmap_id(struct idmap *idmap, struct idmap_hashtable *h,
 200                 const char *name, size_t namelen, __u32 *id)
 201 {
 202         struct rpc_pipe_msg msg;
 203         struct idmap_msg *im;
 204         struct idmap_hashent *he;
 205         DECLARE_WAITQUEUE(wq, current);
 206         int ret = -EIO;
 207
 208         im = &idmap->idmap_im;
 209
 210         /*
 211          * String sanity checks
 212          * Note that the userland daemon expects NUL terminated strings
 213          */
 214         for (;;) {
 215                 if (namelen == 0)
 216                         return -EINVAL;
 217                 if (name[namelen-1] != '\0')
 218                         break;
 219                 namelen--;
 220         }
 221         if (namelen >= IDMAP_NAMESZ)
 222                 return -EINVAL;
 223
 224         down(&idmap->idmap_lock);
 225         down(&idmap->idmap_im_lock);
 226
 227         he = idmap_lookup_name(h, name, namelen);
 228         if (he != NULL) {
 229                 *id = he->ih_id;
 230                 ret = 0;
 231                 goto out;
 232         }
 233
 234         memset(im, 0, sizeof(*im));
 235         memcpy(im->im_name, name, namelen);
 236
 237         im->im_type = h->h_type;
 238         im->im_conv = IDMAP_CONV_NAMETOID;
 239
 240         memset(&msg, 0, sizeof(msg));
 241         msg.data = im;
 242         msg.len = sizeof(*im);
 243
 244         add_wait_queue(&idmap->idmap_wq, &wq);
 245         if (rpc_queue_upcall(idmap->idmap_dentry->d_inode, &msg) < 0) {
 246                 remove_wait_queue(&idmap->idmap_wq, &wq);
 247                 goto out;
 248         }
 249
 250         set_current_state(TASK_UNINTERRUPTIBLE);
 251         up(&idmap->idmap_im_lock);
 252         schedule();
 253         current->state = TASK_RUNNING;
 254         remove_wait_queue(&idmap->idmap_wq, &wq);
 255         down(&idmap->idmap_im_lock);
 256
 257         if (im->im_status & IDMAP_STATUS_SUCCESS) {
 258                 *id = im->im_id;
 259                 ret = 0;
 260         }
 261
 262  out:
 263         memset(im, 0, sizeof(*im));
 264         up(&idmap->idmap_im_lock);
 265         up(&idmap->idmap_lock);
 266         return (ret);
 267 }
 268
 269 /*
 270  * ID -> Name
 271  */
 272 static int
 273 nfs_idmap_name(struct idmap *idmap, struct idmap_hashtable *h,
 274                 __u32 id, char *name)
 275 {
 276         struct rpc_pipe_msg msg;
 277         struct idmap_msg *im;
 278         struct idmap_hashent *he;
 279         DECLARE_WAITQUEUE(wq, current);
 280         int ret = -EIO;
 281         unsigned int len;
 282
 283         im = &idmap->idmap_im;
 284
 285         down(&idmap->idmap_lock);
 286         down(&idmap->idmap_im_lock);
 287
 288         he = idmap_lookup_id(h, id);
 289         if (he != 0) {
 290                 memcpy(name, he->ih_name, he->ih_namelen);
 291                 ret = he->ih_namelen;
 292                 goto out;
 293         }
 294
 295         memset(im, 0, sizeof(*im));
 296         im->im_type = h->h_type;
 297         im->im_conv = IDMAP_CONV_IDTONAME;
 298         im->im_id = id;
 299
 300         memset(&msg, 0, sizeof(msg));
 301         msg.data = im;
 302         msg.len = sizeof(*im);
 303
 304         add_wait_queue(&idmap->idmap_wq, &wq);
 305
 306         if (rpc_queue_upcall(idmap->idmap_dentry->d_inode, &msg) < 0) {
 307                 remove_wait_queue(&idmap->idmap_wq, &wq);
 308                 goto out;
 309         }
 310
 311         set_current_state(TASK_UNINTERRUPTIBLE);
 312         up(&idmap->idmap_im_lock);
 313         schedule();
 314         current->state = TASK_RUNNING;
 315         remove_wait_queue(&idmap->idmap_wq, &wq);
 316         down(&idmap->idmap_im_lock);
 317
 318         if (im->im_status & IDMAP_STATUS_SUCCESS) {
 319                 if ((len = strnlen(im->im_name, IDMAP_NAMESZ)) == 0)
 320                         goto out;
 321                 memcpy(name, im->im_name, len);
 322                 ret = len;
 323         }
 324
 325  out:
 326         memset(im, 0, sizeof(*im));
 327         up(&idmap->idmap_im_lock);
 328         up(&idmap->idmap_lock);
 329         return ret;
 330 }
 331
 332 /* RPC pipefs upcall/downcall routines */
 333 static ssize_t
 334 idmap_pipe_upcall(struct file *filp, struct rpc_pipe_msg *msg,
 335     char *dst, size_t buflen)
 336 {
 337         char *data = (char *)msg->data + msg->copied;
 338         ssize_t mlen = msg->len - msg->copied;
 339         ssize_t left;
 340
 341         if (mlen > buflen)
 342                 mlen = buflen;
 343
 344         left = copy_to_user(dst, data, mlen);
 345         if (left < 0) {
 346                 msg->errno = left;
 347                 return left;
 348         }
 349         mlen -= left;
 350         msg->copied += mlen;
 351         msg->errno = 0;
 352         return mlen;
 353 }
 354
 355 static ssize_t
 356 idmap_pipe_downcall(struct file *filp, const char *src, size_t mlen)
 357 {
 358         struct rpc_inode *rpci = RPC_I(filp->f_dentry->d_inode);
 359         struct idmap *idmap = (struct idmap *)rpci->private;
 360         struct idmap_msg im_in, *im = &idmap->idmap_im;
 361         struct idmap_hashtable *h;
 362         struct idmap_hashent *he = NULL;
 363         int namelen_in;
 364         int ret;
 365
 366         if (mlen != sizeof(im_in))
 367                 return (-ENOSPC);
 368
 369         if (copy_from_user(&im_in, src, mlen) != 0)
 370                 return (-EFAULT);
 371
 372         down(&idmap->idmap_im_lock);
 373
 374         ret = mlen;
 375         im->im_status = im_in.im_status;
 376         /* If we got an error, terminate now, and wake up pending upcalls */
 377         if (!(im_in.im_status & IDMAP_STATUS_SUCCESS)) {
 378                 wake_up(&idmap->idmap_wq);
 379                 goto out;
 380         }
 381
 382         /* Sanity checking of strings */
 383         ret = -EINVAL;
 384         namelen_in = strnlen(im_in.im_name, IDMAP_NAMESZ);
 385         if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ)
 386                 goto out;
 387
 388         switch (im_in.im_type) {
 389                 case IDMAP_TYPE_USER:
 390                         h = &idmap->idmap_user_hash;
 391                         break;
 392                 case IDMAP_TYPE_GROUP:
 393                         h = &idmap->idmap_group_hash;
 394                         break;
 395                 default:
 396                         goto out;
 397         }
 398
 399         switch (im_in.im_conv) {
 400         case IDMAP_CONV_IDTONAME:
 401                 /* Did we match the current upcall? */
 402                 if (im->im_conv == IDMAP_CONV_IDTONAME
 403                                 && im->im_type == im_in.im_type
 404                                 && im->im_id == im_in.im_id) {
 405                         /* Yes: copy string, including the terminating '\0'  */
 406                         memcpy(im->im_name, im_in.im_name, namelen_in);
 407                         im->im_name[namelen_in] = '\0';
 408                         wake_up(&idmap->idmap_wq);
 409                 }
 410                 he = idmap_alloc_id(h, im_in.im_id);
 411                 break;
 412         case IDMAP_CONV_NAMETOID:
 413                 /* Did we match the current upcall? */
 414                 if (im->im_conv == IDMAP_CONV_NAMETOID
 415                                 && im->im_type == im_in.im_type
 416                                 && strnlen(im->im_name, IDMAP_NAMESZ) == namelen_in
 417                                 && memcmp(im->im_name, im_in.im_name, namelen_in) == 0) {
 418                         im->im_id = im_in.im_id;
 419                         wake_up(&idmap->idmap_wq);
 420                 }
 421                 he = idmap_alloc_name(h, im_in.im_name, namelen_in);
 422                 break;
 423         default:
 424                 goto out;
 425         }
 426
 427         /* If the entry is valid, also copy it to the cache */
 428         if (he != NULL)
 429                 idmap_update_entry(he, im_in.im_name, namelen_in, im_in.im_id);
 430         ret = mlen;
 431 out:
 432         up(&idmap->idmap_im_lock);
 433         return ret;
 434 }
 435
 436 void
 437 idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 438 {
 439         struct idmap_msg *im = msg->data;
 440         struct idmap *idmap = container_of(im, struct idmap, idmap_im);
 441
 442         if (msg->errno >= 0)
 443                 return;
 444         down(&idmap->idmap_im_lock);
 445         im->im_status = IDMAP_STATUS_LOOKUPFAIL;
 446         wake_up(&idmap->idmap_wq);
 447         up(&idmap->idmap_im_lock);
 448 }
 449
 450 /*
 451  * Fowler/Noll/Vo hash
 452  *    http://www.isthe.com/chongo/tech/comp/fnv/
 453  */
 454
 455 #define FNV_P_32 ((unsigned int)0x01000193) /* 16777619 */
 456 #define FNV_1_32 ((unsigned int)0x811c9dc5) /* 2166136261 */
 457
 458 static unsigned int fnvhash32(const void *buf, size_t buflen)
 459 {
 460         const unsigned char *p, *end = (const unsigned char *)buf + buflen;
 461         unsigned int hash = FNV_1_32;
 462
 463         for (p = buf; p < end; p++) {
 464                 hash *= FNV_P_32;
 465                 hash ^= (unsigned int)*p;
 466         }
 467
 468         return (hash);
 469 }
 470
 471 int nfs_map_name_to_uid(struct nfs4_client *clp, const char *name, size_t namelen, __u32 *uid)
 472 {
 473         struct idmap *idmap = clp->cl_idmap;
 474
 475         return nfs_idmap_id(idmap, &idmap->idmap_user_hash, name, namelen, uid);
 476 }
 477
 478 int nfs_map_group_to_gid(struct nfs4_client *clp, const char *name, size_t namelen, __u32 *uid)
 479 {
 480         struct idmap *idmap = clp->cl_idmap;
 481
 482         return nfs_idmap_id(idmap, &idmap->idmap_group_hash, name, namelen, uid);
 483 }
 484
 485 int nfs_map_uid_to_name(struct nfs4_client *clp, __u32 uid, char *buf)
 486 {
 487         struct idmap *idmap = clp->cl_idmap;
 488
 489         return nfs_idmap_name(idmap, &idmap->idmap_user_hash, uid, buf);
 490 }
 491 int nfs_map_gid_to_group(struct nfs4_client *clp, __u32 uid, char *buf)
 492 {
 493         struct idmap *idmap = clp->cl_idmap;
 494
 495         return nfs_idmap_name(idmap, &idmap->idmap_group_hash, uid, buf);
 496 }
 497