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