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 int
 112 nfs_idmap_new(struct nfs_client *clp)
 113 {
 114         struct idmap *idmap;
 115         int error;
 116
 117         if (clp->cl_idmap != NULL)
 118                 return 0;
 119
 120         if ((idmap = kzalloc(sizeof(*idmap), GFP_KERNEL)) == NULL)
 121                 return -ENOMEM;
 122
 123         snprintf(idmap->idmap_path, sizeof(idmap->idmap_path),
 124             "%s/idmap", clp->cl_rpcclient->cl_pathname);
 125
 126         idmap->idmap_dentry = rpc_mkpipe(idmap->idmap_path,
 127             idmap, &idmap_upcall_ops, 0);
 128         if (IS_ERR(idmap->idmap_dentry)) {
 129                 error = PTR_ERR(idmap->idmap_dentry);
 130                 kfree(idmap);
 131                 return error;
 132         }
 133
 134         mutex_init(&idmap->idmap_lock);
 135         mutex_init(&idmap->idmap_im_lock);
 136         init_waitqueue_head(&idmap->idmap_wq);
 137         idmap->idmap_user_hash.h_type = IDMAP_TYPE_USER;
 138         idmap->idmap_group_hash.h_type = IDMAP_TYPE_GROUP;
 139
 140         clp->cl_idmap = idmap;
 141         return 0;
 142 }
 143
 144 void
 145 nfs_idmap_delete(struct nfs_client *clp)
 146 {
 147         struct idmap *idmap = clp->cl_idmap;
 148
 149         if (!idmap)
 150                 return;
 151         rpc_unlink(idmap->idmap_dentry);
 152         clp->cl_idmap = NULL;
 153         kfree(idmap);
 154 }
 155
 156 /*
 157  * Helper routines for manipulating the hashtable
 158  */
 159 static inline struct idmap_hashent *
 160 idmap_name_hash(struct idmap_hashtable* h, const char *name, size_t len)
 161 {
 162         return &h->h_entries[fnvhash32(name, len) % IDMAP_HASH_SZ];
 163 }
 164
 165 static struct idmap_hashent *
 166 idmap_lookup_name(struct idmap_hashtable *h, const char *name, size_t len)
 167 {
 168         struct idmap_hashent *he = idmap_name_hash(h, name, len);
 169
 170         if (he->ih_namelen != len || memcmp(he->ih_name, name, len) != 0)
 171                 return NULL;
 172         if (time_after(jiffies, he->ih_expires))
 173                 return NULL;
 174         return he;
 175 }
 176
 177 static inline struct idmap_hashent *
 178 idmap_id_hash(struct idmap_hashtable* h, __u32 id)
 179 {
 180         return &h->h_entries[fnvhash32(&id, sizeof(id)) % IDMAP_HASH_SZ];
 181 }
 182
 183 static struct idmap_hashent *
 184 idmap_lookup_id(struct idmap_hashtable *h, __u32 id)
 185 {
 186         struct idmap_hashent *he = idmap_id_hash(h, id);
 187         if (he->ih_id != id || he->ih_namelen == 0)
 188                 return NULL;
 189         if (time_after(jiffies, he->ih_expires))
 190                 return NULL;
 191         return he;
 192 }
 193
 194 /*
 195  * Routines for allocating new entries in the hashtable.
 196  * For now, we just have 1 entry per bucket, so it's all
 197  * pretty trivial.
 198  */
 199 static inline struct idmap_hashent *
 200 idmap_alloc_name(struct idmap_hashtable *h, char *name, unsigned len)
 201 {
 202         return idmap_name_hash(h, name, len);
 203 }
 204
 205 static inline struct idmap_hashent *
 206 idmap_alloc_id(struct idmap_hashtable *h, __u32 id)
 207 {
 208         return idmap_id_hash(h, id);
 209 }
 210
 211 static void
 212 idmap_update_entry(struct idmap_hashent *he, const char *name,
 213                 size_t namelen, __u32 id)
 214 {
 215         he->ih_id = id;
 216         memcpy(he->ih_name, name, namelen);
 217         he->ih_name[namelen] = '\0';
 218         he->ih_namelen = namelen;
 219         he->ih_expires = jiffies + nfs_idmap_cache_timeout;
 220 }
 221
 222 /*
 223  * Name -> ID
 224  */
 225 static int
 226 nfs_idmap_id(struct idmap *idmap, struct idmap_hashtable *h,
 227                 const char *name, size_t namelen, __u32 *id)
 228 {
 229         struct rpc_pipe_msg msg;
 230         struct idmap_msg *im;
 231         struct idmap_hashent *he;
 232         DECLARE_WAITQUEUE(wq, current);
 233         int ret = -EIO;
 234
 235         im = &idmap->idmap_im;
 236
 237         /*
 238          * String sanity checks
 239          * Note that the userland daemon expects NUL terminated strings
 240          */
 241         for (;;) {
 242                 if (namelen == 0)
 243                         return -EINVAL;
 244                 if (name[namelen-1] != '\0')
 245                         break;
 246                 namelen--;
 247         }
 248         if (namelen >= IDMAP_NAMESZ)
 249                 return -EINVAL;
 250
 251         mutex_lock(&idmap->idmap_lock);
 252         mutex_lock(&idmap->idmap_im_lock);
 253
 254         he = idmap_lookup_name(h, name, namelen);
 255         if (he != NULL) {
 256                 *id = he->ih_id;
 257                 ret = 0;
 258                 goto out;
 259         }
 260
 261         memset(im, 0, sizeof(*im));
 262         memcpy(im->im_name, name, namelen);
 263
 264         im->im_type = h->h_type;
 265         im->im_conv = IDMAP_CONV_NAMETOID;
 266
 267         memset(&msg, 0, sizeof(msg));
 268         msg.data = im;
 269         msg.len = sizeof(*im);
 270
 271         add_wait_queue(&idmap->idmap_wq, &wq);
 272         if (rpc_queue_upcall(idmap->idmap_dentry->d_inode, &msg) < 0) {
 273                 remove_wait_queue(&idmap->idmap_wq, &wq);
 274                 goto out;
 275         }
 276
 277         set_current_state(TASK_UNINTERRUPTIBLE);
 278         mutex_unlock(&idmap->idmap_im_lock);
 279         schedule();
 280         current->state = TASK_RUNNING;
 281         remove_wait_queue(&idmap->idmap_wq, &wq);
 282         mutex_lock(&idmap->idmap_im_lock);
 283
 284         if (im->im_status & IDMAP_STATUS_SUCCESS) {
 285                 *id = im->im_id;
 286                 ret = 0;
 287         }
 288
 289  out:
 290         memset(im, 0, sizeof(*im));
 291         mutex_unlock(&idmap->idmap_im_lock);
 292         mutex_unlock(&idmap->idmap_lock);
 293         return (ret);
 294 }
 295
 296 /*
 297  * ID -> Name
 298  */
 299 static int
 300 nfs_idmap_name(struct idmap *idmap, struct idmap_hashtable *h,
 301                 __u32 id, char *name)
 302 {
 303         struct rpc_pipe_msg msg;
 304         struct idmap_msg *im;
 305         struct idmap_hashent *he;
 306         DECLARE_WAITQUEUE(wq, current);
 307         int ret = -EIO;
 308         unsigned int len;
 309
 310         im = &idmap->idmap_im;
 311
 312         mutex_lock(&idmap->idmap_lock);
 313         mutex_lock(&idmap->idmap_im_lock);
 314
 315         he = idmap_lookup_id(h, id);
 316         if (he != 0) {
 317                 memcpy(name, he->ih_name, he->ih_namelen);
 318                 ret = he->ih_namelen;
 319                 goto out;
 320         }
 321
 322         memset(im, 0, sizeof(*im));
 323         im->im_type = h->h_type;
 324         im->im_conv = IDMAP_CONV_IDTONAME;
 325         im->im_id = id;
 326
 327         memset(&msg, 0, sizeof(msg));
 328         msg.data = im;
 329         msg.len = sizeof(*im);
 330
 331         add_wait_queue(&idmap->idmap_wq, &wq);
 332
 333         if (rpc_queue_upcall(idmap->idmap_dentry->d_inode, &msg) < 0) {
 334                 remove_wait_queue(&idmap->idmap_wq, &wq);
 335                 goto out;
 336         }
 337
 338         set_current_state(TASK_UNINTERRUPTIBLE);
 339         mutex_unlock(&idmap->idmap_im_lock);
 340         schedule();
 341         current->state = TASK_RUNNING;
 342         remove_wait_queue(&idmap->idmap_wq, &wq);
 343         mutex_lock(&idmap->idmap_im_lock);
 344
 345         if (im->im_status & IDMAP_STATUS_SUCCESS) {
 346                 if ((len = strnlen(im->im_name, IDMAP_NAMESZ)) == 0)
 347                         goto out;
 348                 memcpy(name, im->im_name, len);
 349                 ret = len;
 350         }
 351
 352  out:
 353         memset(im, 0, sizeof(*im));
 354         mutex_unlock(&idmap->idmap_im_lock);
 355         mutex_unlock(&idmap->idmap_lock);
 356         return ret;
 357 }
 358
 359 /* RPC pipefs upcall/downcall routines */
 360 static ssize_t
 361 idmap_pipe_upcall(struct file *filp, struct rpc_pipe_msg *msg,
 362     char __user *dst, size_t buflen)
 363 {
 364         char *data = (char *)msg->data + msg->copied;
 365         ssize_t mlen = msg->len - msg->copied;
 366         ssize_t left;
 367
 368         if (mlen > buflen)
 369                 mlen = buflen;
 370
 371         left = copy_to_user(dst, data, mlen);
 372         if (left < 0) {
 373                 msg->errno = left;
 374                 return left;
 375         }
 376         mlen -= left;
 377         msg->copied += mlen;
 378         msg->errno = 0;
 379         return mlen;
 380 }
 381
 382 static ssize_t
 383 idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 384 {
 385         struct rpc_inode *rpci = RPC_I(filp->f_dentry->d_inode);
 386         struct idmap *idmap = (struct idmap *)rpci->private;
 387         struct idmap_msg im_in, *im = &idmap->idmap_im;
 388         struct idmap_hashtable *h;
 389         struct idmap_hashent *he = NULL;
 390         int namelen_in;
 391         int ret;
 392
 393         if (mlen != sizeof(im_in))
 394                 return (-ENOSPC);
 395
 396         if (copy_from_user(&im_in, src, mlen) != 0)
 397                 return (-EFAULT);
 398
 399         mutex_lock(&idmap->idmap_im_lock);
 400
 401         ret = mlen;
 402         im->im_status = im_in.im_status;
 403         /* If we got an error, terminate now, and wake up pending upcalls */
 404         if (!(im_in.im_status & IDMAP_STATUS_SUCCESS)) {
 405                 wake_up(&idmap->idmap_wq);
 406                 goto out;
 407         }
 408
 409         /* Sanity checking of strings */
 410         ret = -EINVAL;
 411         namelen_in = strnlen(im_in.im_name, IDMAP_NAMESZ);
 412         if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ)
 413                 goto out;
 414
 415         switch (im_in.im_type) {
 416                 case IDMAP_TYPE_USER:
 417                         h = &idmap->idmap_user_hash;
 418                         break;
 419                 case IDMAP_TYPE_GROUP:
 420                         h = &idmap->idmap_group_hash;
 421                         break;
 422                 default:
 423                         goto out;
 424         }
 425
 426         switch (im_in.im_conv) {
 427         case IDMAP_CONV_IDTONAME:
 428                 /* Did we match the current upcall? */
 429                 if (im->im_conv == IDMAP_CONV_IDTONAME
 430                                 && im->im_type == im_in.im_type
 431                                 && im->im_id == im_in.im_id) {
 432                         /* Yes: copy string, including the terminating '\0'  */
 433                         memcpy(im->im_name, im_in.im_name, namelen_in);
 434                         im->im_name[namelen_in] = '\0';
 435                         wake_up(&idmap->idmap_wq);
 436                 }
 437                 he = idmap_alloc_id(h, im_in.im_id);
 438                 break;
 439         case IDMAP_CONV_NAMETOID:
 440                 /* Did we match the current upcall? */
 441                 if (im->im_conv == IDMAP_CONV_NAMETOID
 442                                 && im->im_type == im_in.im_type
 443                                 && strnlen(im->im_name, IDMAP_NAMESZ) == namelen_in
 444                                 && memcmp(im->im_name, im_in.im_name, namelen_in) == 0) {
 445                         im->im_id = im_in.im_id;
 446                         wake_up(&idmap->idmap_wq);
 447                 }
 448                 he = idmap_alloc_name(h, im_in.im_name, namelen_in);
 449                 break;
 450         default:
 451                 goto out;
 452         }
 453
 454         /* If the entry is valid, also copy it to the cache */
 455         if (he != NULL)
 456                 idmap_update_entry(he, im_in.im_name, namelen_in, im_in.im_id);
 457         ret = mlen;
 458 out:
 459         mutex_unlock(&idmap->idmap_im_lock);
 460         return ret;
 461 }
 462
 463 static void
 464 idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 465 {
 466         struct idmap_msg *im = msg->data;
 467         struct idmap *idmap = container_of(im, struct idmap, idmap_im);
 468
 469         if (msg->errno >= 0)
 470                 return;
 471         mutex_lock(&idmap->idmap_im_lock);
 472         im->im_status = IDMAP_STATUS_LOOKUPFAIL;
 473         wake_up(&idmap->idmap_wq);
 474         mutex_unlock(&idmap->idmap_im_lock);
 475 }
 476
 477 /*
 478  * Fowler/Noll/Vo hash
 479  *    http://www.isthe.com/chongo/tech/comp/fnv/
 480  */
 481
 482 #define FNV_P_32 ((unsigned int)0x01000193) /* 16777619 */
 483 #define FNV_1_32 ((unsigned int)0x811c9dc5) /* 2166136261 */
 484
 485 static unsigned int fnvhash32(const void *buf, size_t buflen)
 486 {
 487         const unsigned char *p, *end = (const unsigned char *)buf + buflen;
 488         unsigned int hash = FNV_1_32;
 489
 490         for (p = buf; p < end; p++) {
 491                 hash *= FNV_P_32;
 492                 hash ^= (unsigned int)*p;
 493         }
 494
 495         return (hash);
 496 }
 497
 498 int nfs_map_name_to_uid(struct nfs_client *clp, const char *name, size_t namelen, __u32 *uid)
 499 {
 500         struct idmap *idmap = clp->cl_idmap;
 501
 502         return nfs_idmap_id(idmap, &idmap->idmap_user_hash, name, namelen, uid);
 503 }
 504
 505 int nfs_map_group_to_gid(struct nfs_client *clp, const char *name, size_t namelen, __u32 *uid)
 506 {
 507         struct idmap *idmap = clp->cl_idmap;
 508
 509         return nfs_idmap_id(idmap, &idmap->idmap_group_hash, name, namelen, uid);
 510 }
 511
 512 int nfs_map_uid_to_name(struct nfs_client *clp, __u32 uid, char *buf)
 513 {
 514         struct idmap *idmap = clp->cl_idmap;
 515
 516         return nfs_idmap_name(idmap, &idmap->idmap_user_hash, uid, buf);
 517 }
 518 int nfs_map_gid_to_group(struct nfs_client *clp, __u32 uid, char *buf)
 519 {
 520         struct idmap *idmap = clp->cl_idmap;
 521
 522         return nfs_idmap_name(idmap, &idmap->idmap_group_hash, uid, buf);
 523 }
 524