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_sb.h>
  51 #include <linux/nfs_fs.h>
  52
  53 #include <linux/nfs_idmap.h>
  54 #include "nfs4_fs.h"
  55
  56 #define IDMAP_HASH_SZ          128
  57
  58 /* Default cache timeout is 10 minutes */
  59 unsigned int nfs_idmap_cache_timeout = 600 * HZ;
  60
  61 struct idmap_hashent {
  62         unsigned long ih_expires;
  63         __u32 ih_id;
  64         int ih_namelen;
  65         char ih_name[IDMAP_NAMESZ];
  66 };
  67
  68 struct idmap_hashtable {
  69         __u8 h_type;
  70         struct idmap_hashent h_entries[IDMAP_HASH_SZ];
  71 };
  72
  73 struct idmap {
  74         char                  idmap_path[48];
  75         struct dentry        *idmap_dentry;
  76         wait_queue_head_t     idmap_wq;
  77         struct idmap_msg      idmap_im;
  78         struct mutex          idmap_lock;    /* Serializes upcalls */
  79         struct mutex          idmap_im_lock; /* Protects the hashtable */
  80         struct idmap_hashtable idmap_user_hash;
  81         struct idmap_hashtable idmap_group_hash;
  82 };
  83
  84 static ssize_t   idmap_pipe_upcall(struct file *, struct rpc_pipe_msg *,
  85                      char __user *, size_t);
  86 static ssize_t   idmap_pipe_downcall(struct file *, const char __user *,
  87                      size_t);
  88 static void      idmap_pipe_destroy_msg(struct rpc_pipe_msg *);
  89
  90 static unsigned int fnvhash32(const void *, size_t);
  91
  92 static struct rpc_pipe_ops idmap_upcall_ops = {
  93         .upcall         = idmap_pipe_upcall,
  94         .downcall       = idmap_pipe_downcall,
  95         .destroy_msg    = idmap_pipe_destroy_msg,
  96 };
  97
  98 void
  99 nfs_idmap_new(struct nfs4_client *clp)
 100 {
 101         struct idmap *idmap;
 102
 103         if (clp->cl_idmap != NULL)
 104                 return;
 105         if ((idmap = kzalloc(sizeof(*idmap), GFP_KERNEL)) == NULL)
 106                 return;
 107
 108         snprintf(idmap->idmap_path, sizeof(idmap->idmap_path),
 109             "%s/idmap", clp->cl_rpcclient->cl_pathname);
 110
 111         idmap->idmap_dentry = rpc_mkpipe(idmap->idmap_path,
 112             idmap, &idmap_upcall_ops, 0);
 113         if (IS_ERR(idmap->idmap_dentry)) {
 114                 kfree(idmap);
 115                 return;
 116         }
 117
 118         mutex_init(&idmap->idmap_lock);
 119         mutex_init(&idmap->idmap_im_lock);
 120         init_waitqueue_head(&idmap->idmap_wq);
 121         idmap->idmap_user_hash.h_type = IDMAP_TYPE_USER;
 122         idmap->idmap_group_hash.h_type = IDMAP_TYPE_GROUP;
 123
 124         clp->cl_idmap = idmap;
 125 }
 126
 127 void
 128 nfs_idmap_delete(struct nfs4_client *clp)
 129 {
 130         struct idmap *idmap = clp->cl_idmap;
 131
 132         if (!idmap)
 133                 return;
 134         dput(idmap->idmap_dentry);
 135         idmap->idmap_dentry = NULL;
 136         rpc_unlink(idmap->idmap_path);
 137         clp->cl_idmap = NULL;
 138         kfree(idmap);
 139 }
 140
 141 /*
 142  * Helper routines for manipulating the hashtable
 143  */
 144 static inline struct idmap_hashent *
 145 idmap_name_hash(struct idmap_hashtable* h, const char *name, size_t len)
 146 {
 147         return &h->h_entries[fnvhash32(name, len) % IDMAP_HASH_SZ];
 148 }
 149
 150 static struct idmap_hashent *
 151 idmap_lookup_name(struct idmap_hashtable *h, const char *name, size_t len)
 152 {
 153         struct idmap_hashent *he = idmap_name_hash(h, name, len);
 154
 155         if (he->ih_namelen != len || memcmp(he->ih_name, name, len) != 0)
 156                 return NULL;
 157         if (time_after(jiffies, he->ih_expires))
 158                 return NULL;
 159         return he;
 160 }
 161
 162 static inline struct idmap_hashent *
 163 idmap_id_hash(struct idmap_hashtable* h, __u32 id)
 164 {
 165         return &h->h_entries[fnvhash32(&id, sizeof(id)) % IDMAP_HASH_SZ];
 166 }
 167
 168 static struct idmap_hashent *
 169 idmap_lookup_id(struct idmap_hashtable *h, __u32 id)
 170 {
 171         struct idmap_hashent *he = idmap_id_hash(h, id);
 172         if (he->ih_id != id || he->ih_namelen == 0)
 173                 return NULL;
 174         if (time_after(jiffies, he->ih_expires))
 175                 return NULL;
 176         return he;
 177 }
 178
 179 /*
 180  * Routines for allocating new entries in the hashtable.
 181  * For now, we just have 1 entry per bucket, so it's all
 182  * pretty trivial.
 183  */
 184 static inline struct idmap_hashent *
 185 idmap_alloc_name(struct idmap_hashtable *h, char *name, unsigned len)
 186 {
 187         return idmap_name_hash(h, name, len);
 188 }
 189
 190 static inline struct idmap_hashent *
 191 idmap_alloc_id(struct idmap_hashtable *h, __u32 id)
 192 {
 193         return idmap_id_hash(h, id);
 194 }
 195
 196 static void
 197 idmap_update_entry(struct idmap_hashent *he, const char *name,
 198                 size_t namelen, __u32 id)
 199 {
 200         he->ih_id = id;
 201         memcpy(he->ih_name, name, namelen);
 202         he->ih_name[namelen] = '\0';
 203         he->ih_namelen = namelen;
 204         he->ih_expires = jiffies + nfs_idmap_cache_timeout;
 205 }
 206
 207 /*
 208  * Name -> ID
 209  */
 210 static int
 211 nfs_idmap_id(struct idmap *idmap, struct idmap_hashtable *h,
 212                 const char *name, size_t namelen, __u32 *id)
 213 {
 214         struct rpc_pipe_msg msg;
 215         struct idmap_msg *im;
 216         struct idmap_hashent *he;
 217         DECLARE_WAITQUEUE(wq, current);
 218         int ret = -EIO;
 219
 220         im = &idmap->idmap_im;
 221
 222         /*
 223          * String sanity checks
 224          * Note that the userland daemon expects NUL terminated strings
 225          */
 226         for (;;) {
 227                 if (namelen == 0)
 228                         return -EINVAL;
 229                 if (name[namelen-1] != '\0')
 230                         break;
 231                 namelen--;
 232         }
 233         if (namelen >= IDMAP_NAMESZ)
 234                 return -EINVAL;
 235
 236         mutex_lock(&idmap->idmap_lock);
 237         mutex_lock(&idmap->idmap_im_lock);
 238
 239         he = idmap_lookup_name(h, name, namelen);
 240         if (he != NULL) {
 241                 *id = he->ih_id;
 242                 ret = 0;
 243                 goto out;
 244         }
 245
 246         memset(im, 0, sizeof(*im));
 247         memcpy(im->im_name, name, namelen);
 248
 249         im->im_type = h->h_type;
 250         im->im_conv = IDMAP_CONV_NAMETOID;
 251
 252         memset(&msg, 0, sizeof(msg));
 253         msg.data = im;
 254         msg.len = sizeof(*im);
 255
 256         add_wait_queue(&idmap->idmap_wq, &wq);
 257         if (rpc_queue_upcall(idmap->idmap_dentry->d_inode, &msg) < 0) {
 258                 remove_wait_queue(&idmap->idmap_wq, &wq);
 259                 goto out;
 260         }
 261
 262         set_current_state(TASK_UNINTERRUPTIBLE);
 263         mutex_unlock(&idmap->idmap_im_lock);
 264         schedule();
 265         current->state = TASK_RUNNING;
 266         remove_wait_queue(&idmap->idmap_wq, &wq);
 267         mutex_lock(&idmap->idmap_im_lock);
 268
 269         if (im->im_status & IDMAP_STATUS_SUCCESS) {
 270                 *id = im->im_id;
 271                 ret = 0;
 272         }
 273
 274  out:
 275         memset(im, 0, sizeof(*im));
 276         mutex_unlock(&idmap->idmap_im_lock);
 277         mutex_unlock(&idmap->idmap_lock);
 278         return (ret);
 279 }
 280
 281 /*
 282  * ID -> Name
 283  */
 284 static int
 285 nfs_idmap_name(struct idmap *idmap, struct idmap_hashtable *h,
 286                 __u32 id, char *name)
 287 {
 288         struct rpc_pipe_msg msg;
 289         struct idmap_msg *im;
 290         struct idmap_hashent *he;
 291         DECLARE_WAITQUEUE(wq, current);
 292         int ret = -EIO;
 293         unsigned int len;
 294
 295         im = &idmap->idmap_im;
 296
 297         mutex_lock(&idmap->idmap_lock);
 298         mutex_lock(&idmap->idmap_im_lock);
 299
 300         he = idmap_lookup_id(h, id);
 301         if (he != 0) {
 302                 memcpy(name, he->ih_name, he->ih_namelen);
 303                 ret = he->ih_namelen;
 304                 goto out;
 305         }
 306
 307         memset(im, 0, sizeof(*im));
 308         im->im_type = h->h_type;
 309         im->im_conv = IDMAP_CONV_IDTONAME;
 310         im->im_id = id;
 311
 312         memset(&msg, 0, sizeof(msg));
 313         msg.data = im;
 314         msg.len = sizeof(*im);
 315
 316         add_wait_queue(&idmap->idmap_wq, &wq);
 317
 318         if (rpc_queue_upcall(idmap->idmap_dentry->d_inode, &msg) < 0) {
 319                 remove_wait_queue(&idmap->idmap_wq, &wq);
 320                 goto out;
 321         }
 322
 323         set_current_state(TASK_UNINTERRUPTIBLE);
 324         mutex_unlock(&idmap->idmap_im_lock);
 325         schedule();
 326         current->state = TASK_RUNNING;
 327         remove_wait_queue(&idmap->idmap_wq, &wq);
 328         mutex_lock(&idmap->idmap_im_lock);
 329
 330         if (im->im_status & IDMAP_STATUS_SUCCESS) {
 331                 if ((len = strnlen(im->im_name, IDMAP_NAMESZ)) == 0)
 332                         goto out;
 333                 memcpy(name, im->im_name, len);
 334                 ret = len;
 335         }
 336
 337  out:
 338         memset(im, 0, sizeof(*im));
 339         mutex_unlock(&idmap->idmap_im_lock);
 340         mutex_unlock(&idmap->idmap_lock);
 341         return ret;
 342 }
 343
 344 /* RPC pipefs upcall/downcall routines */
 345 static ssize_t
 346 idmap_pipe_upcall(struct file *filp, struct rpc_pipe_msg *msg,
 347     char __user *dst, size_t buflen)
 348 {
 349         char *data = (char *)msg->data + msg->copied;
 350         ssize_t mlen = msg->len - msg->copied;
 351         ssize_t left;
 352
 353         if (mlen > buflen)
 354                 mlen = buflen;
 355
 356         left = copy_to_user(dst, data, mlen);
 357         if (left < 0) {
 358                 msg->errno = left;
 359                 return left;
 360         }
 361         mlen -= left;
 362         msg->copied += mlen;
 363         msg->errno = 0;
 364         return mlen;
 365 }
 366
 367 static ssize_t
 368 idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 369 {
 370         struct rpc_inode *rpci = RPC_I(filp->f_dentry->d_inode);
 371         struct idmap *idmap = (struct idmap *)rpci->private;
 372         struct idmap_msg im_in, *im = &idmap->idmap_im;
 373         struct idmap_hashtable *h;
 374         struct idmap_hashent *he = NULL;
 375         int namelen_in;
 376         int ret;
 377
 378         if (mlen != sizeof(im_in))
 379                 return (-ENOSPC);
 380
 381         if (copy_from_user(&im_in, src, mlen) != 0)
 382                 return (-EFAULT);
 383
 384         mutex_lock(&idmap->idmap_im_lock);
 385
 386         ret = mlen;
 387         im->im_status = im_in.im_status;
 388         /* If we got an error, terminate now, and wake up pending upcalls */
 389         if (!(im_in.im_status & IDMAP_STATUS_SUCCESS)) {
 390                 wake_up(&idmap->idmap_wq);
 391                 goto out;
 392         }
 393
 394         /* Sanity checking of strings */
 395         ret = -EINVAL;
 396         namelen_in = strnlen(im_in.im_name, IDMAP_NAMESZ);
 397         if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ)
 398                 goto out;
 399
 400         switch (im_in.im_type) {
 401                 case IDMAP_TYPE_USER:
 402                         h = &idmap->idmap_user_hash;
 403                         break;
 404                 case IDMAP_TYPE_GROUP:
 405                         h = &idmap->idmap_group_hash;
 406                         break;
 407                 default:
 408                         goto out;
 409         }
 410
 411         switch (im_in.im_conv) {
 412         case IDMAP_CONV_IDTONAME:
 413                 /* Did we match the current upcall? */
 414                 if (im->im_conv == IDMAP_CONV_IDTONAME
 415                                 && im->im_type == im_in.im_type
 416                                 && im->im_id == im_in.im_id) {
 417                         /* Yes: copy string, including the terminating '\0'  */
 418                         memcpy(im->im_name, im_in.im_name, namelen_in);
 419                         im->im_name[namelen_in] = '\0';
 420                         wake_up(&idmap->idmap_wq);
 421                 }
 422                 he = idmap_alloc_id(h, im_in.im_id);
 423                 break;
 424         case IDMAP_CONV_NAMETOID:
 425                 /* Did we match the current upcall? */
 426                 if (im->im_conv == IDMAP_CONV_NAMETOID
 427                                 && im->im_type == im_in.im_type
 428                                 && strnlen(im->im_name, IDMAP_NAMESZ) == namelen_in
 429                                 && memcmp(im->im_name, im_in.im_name, namelen_in) == 0) {
 430                         im->im_id = im_in.im_id;
 431                         wake_up(&idmap->idmap_wq);
 432                 }
 433                 he = idmap_alloc_name(h, im_in.im_name, namelen_in);
 434                 break;
 435         default:
 436                 goto out;
 437         }
 438
 439         /* If the entry is valid, also copy it to the cache */
 440         if (he != NULL)
 441                 idmap_update_entry(he, im_in.im_name, namelen_in, im_in.im_id);
 442         ret = mlen;
 443 out:
 444         mutex_unlock(&idmap->idmap_im_lock);
 445         return ret;
 446 }
 447
 448 static void
 449 idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 450 {
 451         struct idmap_msg *im = msg->data;
 452         struct idmap *idmap = container_of(im, struct idmap, idmap_im);
 453
 454         if (msg->errno >= 0)
 455                 return;
 456         mutex_lock(&idmap->idmap_im_lock);
 457         im->im_status = IDMAP_STATUS_LOOKUPFAIL;
 458         wake_up(&idmap->idmap_wq);
 459         mutex_unlock(&idmap->idmap_im_lock);
 460 }
 461
 462 /*
 463  * Fowler/Noll/Vo hash
 464  *    http://www.isthe.com/chongo/tech/comp/fnv/
 465  */
 466
 467 #define FNV_P_32 ((unsigned int)0x01000193) /* 16777619 */
 468 #define FNV_1_32 ((unsigned int)0x811c9dc5) /* 2166136261 */
 469
 470 static unsigned int fnvhash32(const void *buf, size_t buflen)
 471 {
 472         const unsigned char *p, *end = (const unsigned char *)buf + buflen;
 473         unsigned int hash = FNV_1_32;
 474
 475         for (p = buf; p < end; p++) {
 476                 hash *= FNV_P_32;
 477                 hash ^= (unsigned int)*p;
 478         }
 479
 480         return (hash);
 481 }
 482
 483 int nfs_map_name_to_uid(struct nfs4_client *clp, const char *name, size_t namelen, __u32 *uid)
 484 {
 485         struct idmap *idmap = clp->cl_idmap;
 486
 487         return nfs_idmap_id(idmap, &idmap->idmap_user_hash, name, namelen, uid);
 488 }
 489
 490 int nfs_map_group_to_gid(struct nfs4_client *clp, const char *name, size_t namelen, __u32 *uid)
 491 {
 492         struct idmap *idmap = clp->cl_idmap;
 493
 494         return nfs_idmap_id(idmap, &idmap->idmap_group_hash, name, namelen, uid);
 495 }
 496
 497 int nfs_map_uid_to_name(struct nfs4_client *clp, __u32 uid, char *buf)
 498 {
 499         struct idmap *idmap = clp->cl_idmap;
 500
 501         return nfs_idmap_name(idmap, &idmap->idmap_user_hash, uid, buf);
 502 }
 503 int nfs_map_gid_to_group(struct nfs4_client *clp, __u32 uid, char *buf)
 504 {
 505         struct idmap *idmap = clp->cl_idmap;
 506
 507         return nfs_idmap_name(idmap, &idmap->idmap_group_hash, uid, buf);
 508 }
 509