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/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 static int param_set_idmap_timeout(const char *val, struct kernel_param *kp)
  61 {
  62         char *endp;
  63         int num = simple_strtol(val, &endp, 0);
  64         int jif = num * HZ;
  65         if (endp == val || *endp || num < 0 || jif < num)
  66                 return -EINVAL;
  67         *((int *)kp->arg) = jif;
  68         return 0;
  69 }
  70
  71 module_param_call(idmap_cache_timeout, param_set_idmap_timeout, param_get_int,
  72                  &nfs_idmap_cache_timeout, 0644);
  73
  74 struct idmap_hashent {
  75         unsigned long ih_expires;
  76         __u32 ih_id;
  77         int ih_namelen;
  78         char ih_name[IDMAP_NAMESZ];
  79 };
  80
  81 struct idmap_hashtable {
  82         __u8 h_type;
  83         struct idmap_hashent h_entries[IDMAP_HASH_SZ];
  84 };
  85
  86 struct idmap {
  87         char                  idmap_path[48];
  88         struct dentry        *idmap_dentry;
  89         wait_queue_head_t     idmap_wq;
  90         struct idmap_msg      idmap_im;
  91         struct mutex          idmap_lock;    /* Serializes upcalls */
  92         struct mutex          idmap_im_lock; /* Protects the hashtable */
  93         struct idmap_hashtable idmap_user_hash;
  94         struct idmap_hashtable idmap_group_hash;
  95 };
  96
  97 static ssize_t   idmap_pipe_upcall(struct file *, struct rpc_pipe_msg *,
  98                      char __user *, size_t);
  99 static ssize_t   idmap_pipe_downcall(struct file *, const char __user *,
 100                      size_t);
 101 static void      idmap_pipe_destroy_msg(struct rpc_pipe_msg *);
 102
 103 static unsigned int fnvhash32(const void *, size_t);
 104
 105 static struct rpc_pipe_ops idmap_upcall_ops = {
 106         .upcall         = idmap_pipe_upcall,
 107         .downcall       = idmap_pipe_downcall,
 108         .destroy_msg    = idmap_pipe_destroy_msg,
 109 };
 110
 111 void
 112 nfs_idmap_new(struct nfs4_client *clp)
 113 {
 114         struct idmap *idmap;
 115
 116         if (clp->cl_idmap != NULL)
 117                 return;
 118         if ((idmap = kzalloc(sizeof(*idmap), GFP_KERNEL)) == NULL)
 119                 return;
 120
 121         snprintf(idmap->idmap_path, sizeof(idmap->idmap_path),
 122             "%s/idmap", clp->cl_rpcclient->cl_pathname);
 123
 124         idmap->idmap_dentry = rpc_mkpipe(idmap->idmap_path,
 125             idmap, &idmap_upcall_ops, 0);
 126         if (IS_ERR(idmap->idmap_dentry)) {
 127                 kfree(idmap);
 128                 return;
 129         }
 130
 131         mutex_init(&idmap->idmap_lock);
 132         mutex_init(&idmap->idmap_im_lock);
 133         init_waitqueue_head(&idmap->idmap_wq);
 134         idmap->idmap_user_hash.h_type = IDMAP_TYPE_USER;
 135         idmap->idmap_group_hash.h_type = IDMAP_TYPE_GROUP;
 136
 137         clp->cl_idmap = idmap;
 138 }
 139
 140 void
 141 nfs_idmap_delete(struct nfs4_client *clp)
 142 {
 143         struct idmap *idmap = clp->cl_idmap;
 144
 145         if (!idmap)
 146                 return;
 147         rpc_unlink(idmap->idmap_dentry);
 148         clp->cl_idmap = NULL;
 149         kfree(idmap);
 150 }
 151
 152 /*
 153  * Helper routines for manipulating the hashtable
 154  */
 155 static inline struct idmap_hashent *
 156 idmap_name_hash(struct idmap_hashtable* h, const char *name, size_t len)
 157 {
 158         return &h->h_entries[fnvhash32(name, len) % IDMAP_HASH_SZ];
 159 }
 160
 161 static struct idmap_hashent *
 162 idmap_lookup_name(struct idmap_hashtable *h, const char *name, size_t len)
 163 {
 164         struct idmap_hashent *he = idmap_name_hash(h, name, len);
 165
 166         if (he->ih_namelen != len || memcmp(he->ih_name, name, len) != 0)
 167                 return NULL;
 168         if (time_after(jiffies, he->ih_expires))
 169                 return NULL;
 170         return he;
 171 }
 172
 173 static inline struct idmap_hashent *
 174 idmap_id_hash(struct idmap_hashtable* h, __u32 id)
 175 {
 176         return &h->h_entries[fnvhash32(&id, sizeof(id)) % IDMAP_HASH_SZ];
 177 }
 178
 179 static struct idmap_hashent *
 180 idmap_lookup_id(struct idmap_hashtable *h, __u32 id)
 181 {
 182         struct idmap_hashent *he = idmap_id_hash(h, id);
 183         if (he->ih_id != id || he->ih_namelen == 0)
 184                 return NULL;
 185         if (time_after(jiffies, he->ih_expires))
 186                 return NULL;
 187         return he;
 188 }
 189
 190 /*
 191  * Routines for allocating new entries in the hashtable.
 192  * For now, we just have 1 entry per bucket, so it's all
 193  * pretty trivial.
 194  */
 195 static inline struct idmap_hashent *
 196 idmap_alloc_name(struct idmap_hashtable *h, char *name, unsigned len)
 197 {
 198         return idmap_name_hash(h, name, len);
 199 }
 200
 201 static inline struct idmap_hashent *
 202 idmap_alloc_id(struct idmap_hashtable *h, __u32 id)
 203 {
 204         return idmap_id_hash(h, id);
 205 }
 206
 207 static void
 208 idmap_update_entry(struct idmap_hashent *he, const char *name,
 209                 size_t namelen, __u32 id)
 210 {
 211         he->ih_id = id;
 212         memcpy(he->ih_name, name, namelen);
 213         he->ih_name[namelen] = '\0';
 214         he->ih_namelen = namelen;
 215         he->ih_expires = jiffies + nfs_idmap_cache_timeout;
 216 }
 217
 218 /*
 219  * Name -> ID
 220  */
 221 static int
 222 nfs_idmap_id(struct idmap *idmap, struct idmap_hashtable *h,
 223                 const char *name, size_t namelen, __u32 *id)
 224 {
 225         struct rpc_pipe_msg msg;
 226         struct idmap_msg *im;
 227         struct idmap_hashent *he;
 228         DECLARE_WAITQUEUE(wq, current);
 229         int ret = -EIO;
 230
 231         im = &idmap->idmap_im;
 232
 233         /*
 234          * String sanity checks
 235          * Note that the userland daemon expects NUL terminated strings
 236          */
 237         for (;;) {
 238                 if (namelen == 0)
 239                         return -EINVAL;
 240                 if (name[namelen-1] != '\0')
 241                         break;
 242                 namelen--;
 243         }
 244         if (namelen >= IDMAP_NAMESZ)
 245                 return -EINVAL;
 246
 247         mutex_lock(&idmap->idmap_lock);
 248         mutex_lock(&idmap->idmap_im_lock);
 249
 250         he = idmap_lookup_name(h, name, namelen);
 251         if (he != NULL) {
 252                 *id = he->ih_id;
 253                 ret = 0;
 254                 goto out;
 255         }
 256
 257         memset(im, 0, sizeof(*im));
 258         memcpy(im->im_name, name, namelen);
 259
 260         im->im_type = h->h_type;
 261         im->im_conv = IDMAP_CONV_NAMETOID;
 262
 263         memset(&msg, 0, sizeof(msg));
 264         msg.data = im;
 265         msg.len = sizeof(*im);
 266
 267         add_wait_queue(&idmap->idmap_wq, &wq);
 268         if (rpc_queue_upcall(idmap->idmap_dentry->d_inode, &msg) < 0) {
 269                 remove_wait_queue(&idmap->idmap_wq, &wq);
 270                 goto out;
 271         }
 272
 273         set_current_state(TASK_UNINTERRUPTIBLE);
 274         mutex_unlock(&idmap->idmap_im_lock);
 275         schedule();
 276         current->state = TASK_RUNNING;
 277         remove_wait_queue(&idmap->idmap_wq, &wq);
 278         mutex_lock(&idmap->idmap_im_lock);
 279
 280         if (im->im_status & IDMAP_STATUS_SUCCESS) {
 281                 *id = im->im_id;
 282                 ret = 0;
 283         }
 284
 285  out:
 286         memset(im, 0, sizeof(*im));
 287         mutex_unlock(&idmap->idmap_im_lock);
 288         mutex_unlock(&idmap->idmap_lock);
 289         return (ret);
 290 }
 291
 292 /*
 293  * ID -> Name
 294  */
 295 static int
 296 nfs_idmap_name(struct idmap *idmap, struct idmap_hashtable *h,
 297                 __u32 id, char *name)
 298 {
 299         struct rpc_pipe_msg msg;
 300         struct idmap_msg *im;
 301         struct idmap_hashent *he;
 302         DECLARE_WAITQUEUE(wq, current);
 303         int ret = -EIO;
 304         unsigned int len;
 305
 306         im = &idmap->idmap_im;
 307
 308         mutex_lock(&idmap->idmap_lock);
 309         mutex_lock(&idmap->idmap_im_lock);
 310
 311         he = idmap_lookup_id(h, id);
 312         if (he != 0) {
 313                 memcpy(name, he->ih_name, he->ih_namelen);
 314                 ret = he->ih_namelen;
 315                 goto out;
 316         }
 317
 318         memset(im, 0, sizeof(*im));
 319         im->im_type = h->h_type;
 320         im->im_conv = IDMAP_CONV_IDTONAME;
 321         im->im_id = id;
 322
 323         memset(&msg, 0, sizeof(msg));
 324         msg.data = im;
 325         msg.len = sizeof(*im);
 326
 327         add_wait_queue(&idmap->idmap_wq, &wq);
 328
 329         if (rpc_queue_upcall(idmap->idmap_dentry->d_inode, &msg) < 0) {
 330                 remove_wait_queue(&idmap->idmap_wq, &wq);
 331                 goto out;
 332         }
 333
 334         set_current_state(TASK_UNINTERRUPTIBLE);
 335         mutex_unlock(&idmap->idmap_im_lock);
 336         schedule();
 337         current->state = TASK_RUNNING;
 338         remove_wait_queue(&idmap->idmap_wq, &wq);
 339         mutex_lock(&idmap->idmap_im_lock);
 340
 341         if (im->im_status & IDMAP_STATUS_SUCCESS) {
 342                 if ((len = strnlen(im->im_name, IDMAP_NAMESZ)) == 0)
 343                         goto out;
 344                 memcpy(name, im->im_name, len);
 345                 ret = len;
 346         }
 347
 348  out:
 349         memset(im, 0, sizeof(*im));
 350         mutex_unlock(&idmap->idmap_im_lock);
 351         mutex_unlock(&idmap->idmap_lock);
 352         return ret;
 353 }
 354
 355 /* RPC pipefs upcall/downcall routines */
 356 static ssize_t
 357 idmap_pipe_upcall(struct file *filp, struct rpc_pipe_msg *msg,
 358     char __user *dst, size_t buflen)
 359 {
 360         char *data = (char *)msg->data + msg->copied;
 361         ssize_t mlen = msg->len - msg->copied;
 362         ssize_t left;
 363
 364         if (mlen > buflen)
 365                 mlen = buflen;
 366
 367         left = copy_to_user(dst, data, mlen);
 368         if (left < 0) {
 369                 msg->errno = left;
 370                 return left;
 371         }
 372         mlen -= left;
 373         msg->copied += mlen;
 374         msg->errno = 0;
 375         return mlen;
 376 }
 377
 378 static ssize_t
 379 idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 380 {
 381         struct rpc_inode *rpci = RPC_I(filp->f_dentry->d_inode);
 382         struct idmap *idmap = (struct idmap *)rpci->private;
 383         struct idmap_msg im_in, *im = &idmap->idmap_im;
 384         struct idmap_hashtable *h;
 385         struct idmap_hashent *he = NULL;
 386         int namelen_in;
 387         int ret;
 388
 389         if (mlen != sizeof(im_in))
 390                 return (-ENOSPC);
 391
 392         if (copy_from_user(&im_in, src, mlen) != 0)
 393                 return (-EFAULT);
 394
 395         mutex_lock(&idmap->idmap_im_lock);
 396
 397         ret = mlen;
 398         im->im_status = im_in.im_status;
 399         /* If we got an error, terminate now, and wake up pending upcalls */
 400         if (!(im_in.im_status & IDMAP_STATUS_SUCCESS)) {
 401                 wake_up(&idmap->idmap_wq);
 402                 goto out;
 403         }
 404
 405         /* Sanity checking of strings */
 406         ret = -EINVAL;
 407         namelen_in = strnlen(im_in.im_name, IDMAP_NAMESZ);
 408         if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ)
 409                 goto out;
 410
 411         switch (im_in.im_type) {
 412                 case IDMAP_TYPE_USER:
 413                         h = &idmap->idmap_user_hash;
 414                         break;
 415                 case IDMAP_TYPE_GROUP:
 416                         h = &idmap->idmap_group_hash;
 417                         break;
 418                 default:
 419                         goto out;
 420         }
 421
 422         switch (im_in.im_conv) {
 423         case IDMAP_CONV_IDTONAME:
 424                 /* Did we match the current upcall? */
 425                 if (im->im_conv == IDMAP_CONV_IDTONAME
 426                                 && im->im_type == im_in.im_type
 427                                 && im->im_id == im_in.im_id) {
 428                         /* Yes: copy string, including the terminating '\0'  */
 429                         memcpy(im->im_name, im_in.im_name, namelen_in);
 430                         im->im_name[namelen_in] = '\0';
 431                         wake_up(&idmap->idmap_wq);
 432                 }
 433                 he = idmap_alloc_id(h, im_in.im_id);
 434                 break;
 435         case IDMAP_CONV_NAMETOID:
 436                 /* Did we match the current upcall? */
 437                 if (im->im_conv == IDMAP_CONV_NAMETOID
 438                                 && im->im_type == im_in.im_type
 439                                 && strnlen(im->im_name, IDMAP_NAMESZ) == namelen_in
 440                                 && memcmp(im->im_name, im_in.im_name, namelen_in) == 0) {
 441                         im->im_id = im_in.im_id;
 442                         wake_up(&idmap->idmap_wq);
 443                 }
 444                 he = idmap_alloc_name(h, im_in.im_name, namelen_in);
 445                 break;
 446         default:
 447                 goto out;
 448         }
 449
 450         /* If the entry is valid, also copy it to the cache */
 451         if (he != NULL)
 452                 idmap_update_entry(he, im_in.im_name, namelen_in, im_in.im_id);
 453         ret = mlen;
 454 out:
 455         mutex_unlock(&idmap->idmap_im_lock);
 456         return ret;
 457 }
 458
 459 static void
 460 idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 461 {
 462         struct idmap_msg *im = msg->data;
 463         struct idmap *idmap = container_of(im, struct idmap, idmap_im);
 464
 465         if (msg->errno >= 0)
 466                 return;
 467         mutex_lock(&idmap->idmap_im_lock);
 468         im->im_status = IDMAP_STATUS_LOOKUPFAIL;
 469         wake_up(&idmap->idmap_wq);
 470         mutex_unlock(&idmap->idmap_im_lock);
 471 }
 472
 473 /*
 474  * Fowler/Noll/Vo hash
 475  *    http://www.isthe.com/chongo/tech/comp/fnv/
 476  */
 477
 478 #define FNV_P_32 ((unsigned int)0x01000193) /* 16777619 */
 479 #define FNV_1_32 ((unsigned int)0x811c9dc5) /* 2166136261 */
 480
 481 static unsigned int fnvhash32(const void *buf, size_t buflen)
 482 {
 483         const unsigned char *p, *end = (const unsigned char *)buf + buflen;
 484         unsigned int hash = FNV_1_32;
 485
 486         for (p = buf; p < end; p++) {
 487                 hash *= FNV_P_32;
 488                 hash ^= (unsigned int)*p;
 489         }
 490
 491         return (hash);
 492 }
 493
 494 int nfs_map_name_to_uid(struct nfs4_client *clp, const char *name, size_t namelen, __u32 *uid)
 495 {
 496         struct idmap *idmap = clp->cl_idmap;
 497
 498         return nfs_idmap_id(idmap, &idmap->idmap_user_hash, name, namelen, uid);
 499 }
 500
 501 int nfs_map_group_to_gid(struct nfs4_client *clp, const char *name, size_t namelen, __u32 *uid)
 502 {
 503         struct idmap *idmap = clp->cl_idmap;
 504
 505         return nfs_idmap_id(idmap, &idmap->idmap_group_hash, name, namelen, uid);
 506 }
 507
 508 int nfs_map_uid_to_name(struct nfs4_client *clp, __u32 uid, char *buf)
 509 {
 510         struct idmap *idmap = clp->cl_idmap;
 511
 512         return nfs_idmap_name(idmap, &idmap->idmap_user_hash, uid, buf);
 513 }
 514 int nfs_map_gid_to_group(struct nfs4_client *clp, __u32 uid, char *buf)
 515 {
 516         struct idmap *idmap = clp->cl_idmap;
 517
 518         return nfs_idmap_name(idmap, &idmap->idmap_group_hash, uid, buf);
 519 }
 520