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 <[email protected]>
  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/mutex.h>
  39 #include <linux/init.h>
  40 #include <linux/types.h>
  41 #include <linux/slab.h>
  42 #include <linux/socket.h>
  43 #include <linux/in.h>
  44 #include <linux/sched.h>
  45
  46 #include <linux/sunrpc/clnt.h>
  47 #include <linux/workqueue.h>
  48 #include <linux/sunrpc/rpc_pipe_fs.h>
  49
  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 mutex          idmap_lock;    /* Serializes upcalls */
  78         struct mutex          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 = kzalloc(sizeof(*idmap), GFP_KERNEL)) == NULL)
 105                 return;
 106
 107         snprintf(idmap->idmap_path, sizeof(idmap->idmap_path),
 108             "%s/idmap", clp->cl_rpcclient->cl_pathname);
 109
 110         idmap->idmap_dentry = rpc_mkpipe(idmap->idmap_path,
 111             idmap, &idmap_upcall_ops, 0);
 112         if (IS_ERR(idmap->idmap_dentry)) {
 113                 kfree(idmap);
 114                 return;
 115         }
 116
 117         mutex_init(&idmap->idmap_lock);
 118         mutex_init(&idmap->idmap_im_lock);
 119         init_waitqueue_head(&idmap->idmap_wq);
 120         idmap->idmap_user_hash.h_type = IDMAP_TYPE_USER;
 121         idmap->idmap_group_hash.h_type = IDMAP_TYPE_GROUP;
 122
 123         clp->cl_idmap = idmap;
 124 }
 125
 126 void
 127 nfs_idmap_delete(struct nfs4_client *clp)
 128 {
 129         struct idmap *idmap = clp->cl_idmap;
 130
 131         if (!idmap)
 132                 return;
 133         rpc_unlink(idmap->idmap_dentry);
 134         clp->cl_idmap = NULL;
 135         kfree(idmap);
 136 }
 137
 138 /*
 139  * Helper routines for manipulating the hashtable
 140  */
 141 static inline struct idmap_hashent *
 142 idmap_name_hash(struct idmap_hashtable* h, const char *name, size_t len)
 143 {
 144         return &h->h_entries[fnvhash32(name, len) % IDMAP_HASH_SZ];
 145 }
 146
 147 static struct idmap_hashent *
 148 idmap_lookup_name(struct idmap_hashtable *h, const char *name, size_t len)
 149 {
 150         struct idmap_hashent *he = idmap_name_hash(h, name, len);
 151
 152         if (he->ih_namelen != len || memcmp(he->ih_name, name, len) != 0)
 153                 return NULL;
 154         if (time_after(jiffies, he->ih_expires))
 155                 return NULL;
 156         return he;
 157 }
 158
 159 static inline struct idmap_hashent *
 160 idmap_id_hash(struct idmap_hashtable* h, __u32 id)
 161 {
 162         return &h->h_entries[fnvhash32(&id, sizeof(id)) % IDMAP_HASH_SZ];
 163 }
 164
 165 static struct idmap_hashent *
 166 idmap_lookup_id(struct idmap_hashtable *h, __u32 id)
 167 {
 168         struct idmap_hashent *he = idmap_id_hash(h, id);
 169         if (he->ih_id != id || he->ih_namelen == 0)
 170                 return NULL;
 171         if (time_after(jiffies, he->ih_expires))
 172                 return NULL;
 173         return he;
 174 }
 175
 176 /*
 177  * Routines for allocating new entries in the hashtable.
 178  * For now, we just have 1 entry per bucket, so it's all
 179  * pretty trivial.
 180  */
 181 static inline struct idmap_hashent *
 182 idmap_alloc_name(struct idmap_hashtable *h, char *name, unsigned len)
 183 {
 184         return idmap_name_hash(h, name, len);
 185 }
 186
 187 static inline struct idmap_hashent *
 188 idmap_alloc_id(struct idmap_hashtable *h, __u32 id)
 189 {
 190         return idmap_id_hash(h, id);
 191 }
 192
 193 static void
 194 idmap_update_entry(struct idmap_hashent *he, const char *name,
 195                 size_t namelen, __u32 id)
 196 {
 197         he->ih_id = id;
 198         memcpy(he->ih_name, name, namelen);
 199         he->ih_name[namelen] = '\0';
 200         he->ih_namelen = namelen;
 201         he->ih_expires = jiffies + nfs_idmap_cache_timeout;
 202 }
 203
 204 /*
 205  * Name -> ID
 206  */
 207 static int
 208 nfs_idmap_id(struct idmap *idmap, struct idmap_hashtable *h,
 209                 const char *name, size_t namelen, __u32 *id)
 210 {
 211         struct rpc_pipe_msg msg;
 212         struct idmap_msg *im;
 213         struct idmap_hashent *he;
 214         DECLARE_WAITQUEUE(wq, current);
 215         int ret = -EIO;
 216
 217         im = &idmap->idmap_im;
 218
 219         /*
 220          * String sanity checks
 221          * Note that the userland daemon expects NUL terminated strings
 222          */
 223         for (;;) {
 224                 if (namelen == 0)
 225                         return -EINVAL;
 226                 if (name[namelen-1] != '\0')
 227                         break;
 228                 namelen--;
 229         }
 230         if (namelen >= IDMAP_NAMESZ)
 231                 return -EINVAL;
 232
 233         mutex_lock(&idmap->idmap_lock);
 234         mutex_lock(&idmap->idmap_im_lock);
 235
 236         he = idmap_lookup_name(h, name, namelen);
 237         if (he != NULL) {
 238                 *id = he->ih_id;
 239                 ret = 0;
 240                 goto out;
 241         }
 242
 243         memset(im, 0, sizeof(*im));
 244         memcpy(im->im_name, name, namelen);
 245
 246         im->im_type = h->h_type;
 247         im->im_conv = IDMAP_CONV_NAMETOID;
 248
 249         memset(&msg, 0, sizeof(msg));
 250         msg.data = im;
 251         msg.len = sizeof(*im);
 252
 253         add_wait_queue(&idmap->idmap_wq, &wq);
 254         if (rpc_queue_upcall(idmap->idmap_dentry->d_inode, &msg) < 0) {
 255                 remove_wait_queue(&idmap->idmap_wq, &wq);
 256                 goto out;
 257         }
 258
 259         set_current_state(TASK_UNINTERRUPTIBLE);
 260         mutex_unlock(&idmap->idmap_im_lock);
 261         schedule();
 262         current->state = TASK_RUNNING;
 263         remove_wait_queue(&idmap->idmap_wq, &wq);
 264         mutex_lock(&idmap->idmap_im_lock);
 265
 266         if (im->im_status & IDMAP_STATUS_SUCCESS) {
 267                 *id = im->im_id;
 268                 ret = 0;
 269         }
 270
 271  out:
 272         memset(im, 0, sizeof(*im));
 273         mutex_unlock(&idmap->idmap_im_lock);
 274         mutex_unlock(&idmap->idmap_lock);
 275         return (ret);
 276 }
 277
 278 /*
 279  * ID -> Name
 280  */
 281 static int
 282 nfs_idmap_name(struct idmap *idmap, struct idmap_hashtable *h,
 283                 __u32 id, char *name)
 284 {
 285         struct rpc_pipe_msg msg;
 286         struct idmap_msg *im;
 287         struct idmap_hashent *he;
 288         DECLARE_WAITQUEUE(wq, current);
 289         int ret = -EIO;
 290         unsigned int len;
 291
 292         im = &idmap->idmap_im;
 293
 294         mutex_lock(&idmap->idmap_lock);
 295         mutex_lock(&idmap->idmap_im_lock);
 296
 297         he = idmap_lookup_id(h, id);
 298         if (he != 0) {
 299                 memcpy(name, he->ih_name, he->ih_namelen);
 300                 ret = he->ih_namelen;
 301                 goto out;
 302         }
 303
 304         memset(im, 0, sizeof(*im));
 305         im->im_type = h->h_type;
 306         im->im_conv = IDMAP_CONV_IDTONAME;
 307         im->im_id = id;
 308
 309         memset(&msg, 0, sizeof(msg));
 310         msg.data = im;
 311         msg.len = sizeof(*im);
 312
 313         add_wait_queue(&idmap->idmap_wq, &wq);
 314
 315         if (rpc_queue_upcall(idmap->idmap_dentry->d_inode, &msg) < 0) {
 316                 remove_wait_queue(&idmap->idmap_wq, &wq);
 317                 goto out;
 318         }
 319
 320         set_current_state(TASK_UNINTERRUPTIBLE);
 321         mutex_unlock(&idmap->idmap_im_lock);
 322         schedule();
 323         current->state = TASK_RUNNING;
 324         remove_wait_queue(&idmap->idmap_wq, &wq);
 325         mutex_lock(&idmap->idmap_im_lock);
 326
 327         if (im->im_status & IDMAP_STATUS_SUCCESS) {
 328                 if ((len = strnlen(im->im_name, IDMAP_NAMESZ)) == 0)
 329                         goto out;
 330                 memcpy(name, im->im_name, len);
 331                 ret = len;
 332         }
 333
 334  out:
 335         memset(im, 0, sizeof(*im));
 336         mutex_unlock(&idmap->idmap_im_lock);
 337         mutex_unlock(&idmap->idmap_lock);
 338         return ret;
 339 }
 340
 341 /* RPC pipefs upcall/downcall routines */
 342 static ssize_t
 343 idmap_pipe_upcall(struct file *filp, struct rpc_pipe_msg *msg,
 344     char __user *dst, size_t buflen)
 345 {
 346         char *data = (char *)msg->data + msg->copied;
 347         ssize_t mlen = msg->len - msg->copied;
 348         ssize_t left;
 349
 350         if (mlen > buflen)
 351                 mlen = buflen;
 352
 353         left = copy_to_user(dst, data, mlen);
 354         if (left < 0) {
 355                 msg->errno = left;
 356                 return left;
 357         }
 358         mlen -= left;
 359         msg->copied += mlen;
 360         msg->errno = 0;
 361         return mlen;
 362 }
 363
 364 static ssize_t
 365 idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 366 {
 367         struct rpc_inode *rpci = RPC_I(filp->f_dentry->d_inode);
 368         struct idmap *idmap = (struct idmap *)rpci->private;
 369         struct idmap_msg im_in, *im = &idmap->idmap_im;
 370         struct idmap_hashtable *h;
 371         struct idmap_hashent *he = NULL;
 372         int namelen_in;
 373         int ret;
 374
 375         if (mlen != sizeof(im_in))
 376                 return (-ENOSPC);
 377
 378         if (copy_from_user(&im_in, src, mlen) != 0)
 379                 return (-EFAULT);
 380
 381         mutex_lock(&idmap->idmap_im_lock);
 382
 383         ret = mlen;
 384         im->im_status = im_in.im_status;
 385         /* If we got an error, terminate now, and wake up pending upcalls */
 386         if (!(im_in.im_status & IDMAP_STATUS_SUCCESS)) {
 387                 wake_up(&idmap->idmap_wq);
 388                 goto out;
 389         }
 390
 391         /* Sanity checking of strings */
 392         ret = -EINVAL;
 393         namelen_in = strnlen(im_in.im_name, IDMAP_NAMESZ);
 394         if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ)
 395                 goto out;
 396
 397         switch (im_in.im_type) {
 398                 case IDMAP_TYPE_USER:
 399                         h = &idmap->idmap_user_hash;
 400                         break;
 401                 case IDMAP_TYPE_GROUP:
 402                         h = &idmap->idmap_group_hash;
 403                         break;
 404                 default:
 405                         goto out;
 406         }
 407
 408         switch (im_in.im_conv) {
 409         case IDMAP_CONV_IDTONAME:
 410                 /* Did we match the current upcall? */
 411                 if (im->im_conv == IDMAP_CONV_IDTONAME
 412                                 && im->im_type == im_in.im_type
 413                                 && im->im_id == im_in.im_id) {
 414                         /* Yes: copy string, including the terminating '\0'  */
 415                         memcpy(im->im_name, im_in.im_name, namelen_in);
 416                         im->im_name[namelen_in] = '\0';
 417                         wake_up(&idmap->idmap_wq);
 418                 }
 419                 he = idmap_alloc_id(h, im_in.im_id);
 420                 break;
 421         case IDMAP_CONV_NAMETOID:
 422                 /* Did we match the current upcall? */
 423                 if (im->im_conv == IDMAP_CONV_NAMETOID
 424                                 && im->im_type == im_in.im_type
 425                                 && strnlen(im->im_name, IDMAP_NAMESZ) == namelen_in
 426                                 && memcmp(im->im_name, im_in.im_name, namelen_in) == 0) {
 427                         im->im_id = im_in.im_id;
 428                         wake_up(&idmap->idmap_wq);
 429                 }
 430                 he = idmap_alloc_name(h, im_in.im_name, namelen_in);
 431                 break;
 432         default:
 433                 goto out;
 434         }
 435
 436         /* If the entry is valid, also copy it to the cache */
 437         if (he != NULL)
 438                 idmap_update_entry(he, im_in.im_name, namelen_in, im_in.im_id);
 439         ret = mlen;
 440 out:
 441         mutex_unlock(&idmap->idmap_im_lock);
 442         return ret;
 443 }
 444
 445 static void
 446 idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 447 {
 448         struct idmap_msg *im = msg->data;
 449         struct idmap *idmap = container_of(im, struct idmap, idmap_im);
 450
 451         if (msg->errno >= 0)
 452                 return;
 453         mutex_lock(&idmap->idmap_im_lock);
 454         im->im_status = IDMAP_STATUS_LOOKUPFAIL;
 455         wake_up(&idmap->idmap_wq);
 456         mutex_unlock(&idmap->idmap_im_lock);
 457 }
 458
 459 /*
 460  * Fowler/Noll/Vo hash
 461  *    http://www.isthe.com/chongo/tech/comp/fnv/
 462  */
 463
 464 #define FNV_P_32 ((unsigned int)0x01000193) /* 16777619 */
 465 #define FNV_1_32 ((unsigned int)0x811c9dc5) /* 2166136261 */
 466
 467 static unsigned int fnvhash32(const void *buf, size_t buflen)
 468 {
 469         const unsigned char *p, *end = (const unsigned char *)buf + buflen;
 470         unsigned int hash = FNV_1_32;
 471
 472         for (p = buf; p < end; p++) {
 473                 hash *= FNV_P_32;
 474                 hash ^= (unsigned int)*p;
 475         }
 476
 477         return (hash);
 478 }
 479
 480 int nfs_map_name_to_uid(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_user_hash, name, namelen, uid);
 485 }
 486
 487 int nfs_map_group_to_gid(struct nfs4_client *clp, const char *name, size_t namelen, __u32 *uid)
 488 {
 489         struct idmap *idmap = clp->cl_idmap;
 490
 491         return nfs_idmap_id(idmap, &idmap->idmap_group_hash, name, namelen, uid);
 492 }
 493
 494 int nfs_map_uid_to_name(struct nfs4_client *clp, __u32 uid, char *buf)
 495 {
 496         struct idmap *idmap = clp->cl_idmap;
 497
 498         return nfs_idmap_name(idmap, &idmap->idmap_user_hash, uid, buf);
 499 }
 500 int nfs_map_gid_to_group(struct nfs4_client *clp, __u32 uid, char *buf)
 501 {
 502         struct idmap *idmap = clp->cl_idmap;
 503
 504         return nfs_idmap_name(idmap, &idmap->idmap_group_hash, uid, buf);
 505 }
 506