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/init.h>
  39 #include <linux/types.h>
  40 #include <linux/slab.h>
  41 #include <linux/socket.h>
  42 #include <linux/in.h>
  43 #include <linux/sched.h>
  44
  45 #include <linux/sunrpc/clnt.h>
  46 #include <linux/workqueue.h>
  47 #include <linux/sunrpc/rpc_pipe_fs.h>
  48
  49 #include <linux/nfs_fs_sb.h>
  50 #include <linux/nfs_fs.h>
  51
  52 #include <linux/nfs_idmap.h>
  53
  54 #define IDMAP_HASH_SZ          128
  55
  56 struct idmap_hashent {
  57         __u32 ih_id;
  58         int ih_namelen;
  59         char ih_name[IDMAP_NAMESZ];
  60 };
  61
  62 struct idmap_hashtable {
  63         __u8 h_type;
  64         struct idmap_hashent h_entries[IDMAP_HASH_SZ];
  65 };
  66
  67 struct idmap {
  68         char                  idmap_path[48];
  69         struct dentry        *idmap_dentry;
  70         wait_queue_head_t     idmap_wq;
  71         struct idmap_msg      idmap_im;
  72         struct semaphore      idmap_lock;    /* Serializes upcalls */
  73         struct semaphore      idmap_im_lock; /* Protects the hashtable */
  74         struct idmap_hashtable idmap_user_hash;
  75         struct idmap_hashtable idmap_group_hash;
  76 };
  77
  78 static ssize_t   idmap_pipe_upcall(struct file *, struct rpc_pipe_msg *,
  79                      char __user *, size_t);
  80 static ssize_t   idmap_pipe_downcall(struct file *, const char __user *,
  81                      size_t);
  82 static void      idmap_pipe_destroy_msg(struct rpc_pipe_msg *);
  83
  84 static unsigned int fnvhash32(const void *, size_t);
  85
  86 static struct rpc_pipe_ops idmap_upcall_ops = {
  87         .upcall         = idmap_pipe_upcall,
  88         .downcall       = idmap_pipe_downcall,
  89         .destroy_msg    = idmap_pipe_destroy_msg,
  90 };
  91
  92 void
  93 nfs_idmap_new(struct nfs4_client *clp)
  94 {
  95         struct idmap *idmap;
  96
  97         if (clp->cl_idmap != NULL)
  98                 return;
  99         if ((idmap = kmalloc(sizeof(*idmap), GFP_KERNEL)) == NULL)
 100                 return;
 101
 102         memset(idmap, 0, sizeof(*idmap));
 103
 104         snprintf(idmap->idmap_path, sizeof(idmap->idmap_path),
 105             "%s/idmap", clp->cl_rpcclient->cl_pathname);
 106
 107         idmap->idmap_dentry = rpc_mkpipe(idmap->idmap_path,
 108             idmap, &idmap_upcall_ops, 0);
 109         if (IS_ERR(idmap->idmap_dentry)) {
 110                 kfree(idmap);
 111                 return;
 112         }
 113
 114         init_MUTEX(&idmap->idmap_lock);
 115         init_MUTEX(&idmap->idmap_im_lock);
 116         init_waitqueue_head(&idmap->idmap_wq);
 117         idmap->idmap_user_hash.h_type = IDMAP_TYPE_USER;
 118         idmap->idmap_group_hash.h_type = IDMAP_TYPE_GROUP;
 119
 120         clp->cl_idmap = idmap;
 121 }
 122
 123 void
 124 nfs_idmap_delete(struct nfs4_client *clp)
 125 {
 126         struct idmap *idmap = clp->cl_idmap;
 127
 128         if (!idmap)
 129                 return;
 130         rpc_unlink(idmap->idmap_path);
 131         clp->cl_idmap = NULL;
 132         kfree(idmap);
 133 }
 134
 135 /*
 136  * Helper routines for manipulating the hashtable
 137  */
 138 static inline struct idmap_hashent *
 139 idmap_name_hash(struct idmap_hashtable* h, const char *name, size_t len)
 140 {
 141         return &h->h_entries[fnvhash32(name, len) % IDMAP_HASH_SZ];
 142 }
 143
 144 static struct idmap_hashent *
 145 idmap_lookup_name(struct idmap_hashtable *h, const char *name, size_t len)
 146 {
 147         struct idmap_hashent *he = idmap_name_hash(h, name, len);
 148
 149         if (he->ih_namelen != len || memcmp(he->ih_name, name, len) != 0)
 150                 return NULL;
 151         return he;
 152 }
 153
 154 static inline struct idmap_hashent *
 155 idmap_id_hash(struct idmap_hashtable* h, __u32 id)
 156 {
 157         return &h->h_entries[fnvhash32(&id, sizeof(id)) % IDMAP_HASH_SZ];
 158 }
 159
 160 static struct idmap_hashent *
 161 idmap_lookup_id(struct idmap_hashtable *h, __u32 id)
 162 {
 163         struct idmap_hashent *he = idmap_id_hash(h, id);
 164         if (he->ih_id != id || he->ih_namelen == 0)
 165                 return NULL;
 166         return he;
 167 }
 168
 169 /*
 170  * Routines for allocating new entries in the hashtable.
 171  * For now, we just have 1 entry per bucket, so it's all
 172  * pretty trivial.
 173  */
 174 static inline struct idmap_hashent *
 175 idmap_alloc_name(struct idmap_hashtable *h, char *name, unsigned len)
 176 {
 177         return idmap_name_hash(h, name, len);
 178 }
 179
 180 static inline struct idmap_hashent *
 181 idmap_alloc_id(struct idmap_hashtable *h, __u32 id)
 182 {
 183         return idmap_id_hash(h, id);
 184 }
 185
 186 static void
 187 idmap_update_entry(struct idmap_hashent *he, const char *name,
 188                 size_t namelen, __u32 id)
 189 {
 190         he->ih_id = id;
 191         memcpy(he->ih_name, name, namelen);
 192         he->ih_name[namelen] = '\0';
 193         he->ih_namelen = namelen;
 194 }
 195
 196 /*
 197  * Name -> ID
 198  */
 199 static int
 200 nfs_idmap_id(struct idmap *idmap, struct idmap_hashtable *h,
 201                 const char *name, size_t namelen, __u32 *id)
 202 {
 203         struct rpc_pipe_msg msg;
 204         struct idmap_msg *im;
 205         struct idmap_hashent *he;
 206         DECLARE_WAITQUEUE(wq, current);
 207         int ret = -EIO;
 208
 209         im = &idmap->idmap_im;
 210
 211         /*
 212          * String sanity checks
 213          * Note that the userland daemon expects NUL terminated strings
 214          */
 215         for (;;) {
 216                 if (namelen == 0)
 217                         return -EINVAL;
 218                 if (name[namelen-1] != '\0')
 219                         break;
 220                 namelen--;
 221         }
 222         if (namelen >= IDMAP_NAMESZ)
 223                 return -EINVAL;
 224
 225         down(&idmap->idmap_lock);
 226         down(&idmap->idmap_im_lock);
 227
 228         he = idmap_lookup_name(h, name, namelen);
 229         if (he != NULL) {
 230                 *id = he->ih_id;
 231                 ret = 0;
 232                 goto out;
 233         }
 234
 235         memset(im, 0, sizeof(*im));
 236         memcpy(im->im_name, name, namelen);
 237
 238         im->im_type = h->h_type;
 239         im->im_conv = IDMAP_CONV_NAMETOID;
 240
 241         memset(&msg, 0, sizeof(msg));
 242         msg.data = im;
 243         msg.len = sizeof(*im);
 244
 245         add_wait_queue(&idmap->idmap_wq, &wq);
 246         if (rpc_queue_upcall(idmap->idmap_dentry->d_inode, &msg) < 0) {
 247                 remove_wait_queue(&idmap->idmap_wq, &wq);
 248                 goto out;
 249         }
 250
 251         set_current_state(TASK_UNINTERRUPTIBLE);
 252         up(&idmap->idmap_im_lock);
 253         schedule();
 254         current->state = TASK_RUNNING;
 255         remove_wait_queue(&idmap->idmap_wq, &wq);
 256         down(&idmap->idmap_im_lock);
 257
 258         if (im->im_status & IDMAP_STATUS_SUCCESS) {
 259                 *id = im->im_id;
 260                 ret = 0;
 261         }
 262
 263  out:
 264         memset(im, 0, sizeof(*im));
 265         up(&idmap->idmap_im_lock);
 266         up(&idmap->idmap_lock);
 267         return (ret);
 268 }
 269
 270 /*
 271  * ID -> Name
 272  */
 273 static int
 274 nfs_idmap_name(struct idmap *idmap, struct idmap_hashtable *h,
 275                 __u32 id, char *name)
 276 {
 277         struct rpc_pipe_msg msg;
 278         struct idmap_msg *im;
 279         struct idmap_hashent *he;
 280         DECLARE_WAITQUEUE(wq, current);
 281         int ret = -EIO;
 282         unsigned int len;
 283
 284         im = &idmap->idmap_im;
 285
 286         down(&idmap->idmap_lock);
 287         down(&idmap->idmap_im_lock);
 288
 289         he = idmap_lookup_id(h, id);
 290         if (he != 0) {
 291                 memcpy(name, he->ih_name, he->ih_namelen);
 292                 ret = he->ih_namelen;
 293                 goto out;
 294         }
 295
 296         memset(im, 0, sizeof(*im));
 297         im->im_type = h->h_type;
 298         im->im_conv = IDMAP_CONV_IDTONAME;
 299         im->im_id = id;
 300
 301         memset(&msg, 0, sizeof(msg));
 302         msg.data = im;
 303         msg.len = sizeof(*im);
 304
 305         add_wait_queue(&idmap->idmap_wq, &wq);
 306
 307         if (rpc_queue_upcall(idmap->idmap_dentry->d_inode, &msg) < 0) {
 308                 remove_wait_queue(&idmap->idmap_wq, &wq);
 309                 goto out;
 310         }
 311
 312         set_current_state(TASK_UNINTERRUPTIBLE);
 313         up(&idmap->idmap_im_lock);
 314         schedule();
 315         current->state = TASK_RUNNING;
 316         remove_wait_queue(&idmap->idmap_wq, &wq);
 317         down(&idmap->idmap_im_lock);
 318
 319         if (im->im_status & IDMAP_STATUS_SUCCESS) {
 320                 if ((len = strnlen(im->im_name, IDMAP_NAMESZ)) == 0)
 321                         goto out;
 322                 memcpy(name, im->im_name, len);
 323                 ret = len;
 324         }
 325
 326  out:
 327         memset(im, 0, sizeof(*im));
 328         up(&idmap->idmap_im_lock);
 329         up(&idmap->idmap_lock);
 330         return ret;
 331 }
 332
 333 /* RPC pipefs upcall/downcall routines */
 334 static ssize_t
 335 idmap_pipe_upcall(struct file *filp, struct rpc_pipe_msg *msg,
 336     char __user *dst, size_t buflen)
 337 {
 338         char *data = (char *)msg->data + msg->copied;
 339         ssize_t mlen = msg->len - msg->copied;
 340         ssize_t left;
 341
 342         if (mlen > buflen)
 343                 mlen = buflen;
 344
 345         left = copy_to_user(dst, data, mlen);
 346         if (left < 0) {
 347                 msg->errno = left;
 348                 return left;
 349         }
 350         mlen -= left;
 351         msg->copied += mlen;
 352         msg->errno = 0;
 353         return mlen;
 354 }
 355
 356 static ssize_t
 357 idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 358 {
 359         struct rpc_inode *rpci = RPC_I(filp->f_dentry->d_inode);
 360         struct idmap *idmap = (struct idmap *)rpci->private;
 361         struct idmap_msg im_in, *im = &idmap->idmap_im;
 362         struct idmap_hashtable *h;
 363         struct idmap_hashent *he = NULL;
 364         int namelen_in;
 365         int ret;
 366
 367         if (mlen != sizeof(im_in))
 368                 return (-ENOSPC);
 369
 370         if (copy_from_user(&im_in, src, mlen) != 0)
 371                 return (-EFAULT);
 372
 373         down(&idmap->idmap_im_lock);
 374
 375         ret = mlen;
 376         im->im_status = im_in.im_status;
 377         /* If we got an error, terminate now, and wake up pending upcalls */
 378         if (!(im_in.im_status & IDMAP_STATUS_SUCCESS)) {
 379                 wake_up(&idmap->idmap_wq);
 380                 goto out;
 381         }
 382
 383         /* Sanity checking of strings */
 384         ret = -EINVAL;
 385         namelen_in = strnlen(im_in.im_name, IDMAP_NAMESZ);
 386         if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ)
 387                 goto out;
 388
 389         switch (im_in.im_type) {
 390                 case IDMAP_TYPE_USER:
 391                         h = &idmap->idmap_user_hash;
 392                         break;
 393                 case IDMAP_TYPE_GROUP:
 394                         h = &idmap->idmap_group_hash;
 395                         break;
 396                 default:
 397                         goto out;
 398         }
 399
 400         switch (im_in.im_conv) {
 401         case IDMAP_CONV_IDTONAME:
 402                 /* Did we match the current upcall? */
 403                 if (im->im_conv == IDMAP_CONV_IDTONAME
 404                                 && im->im_type == im_in.im_type
 405                                 && im->im_id == im_in.im_id) {
 406                         /* Yes: copy string, including the terminating '\0'  */
 407                         memcpy(im->im_name, im_in.im_name, namelen_in);
 408                         im->im_name[namelen_in] = '\0';
 409                         wake_up(&idmap->idmap_wq);
 410                 }
 411                 he = idmap_alloc_id(h, im_in.im_id);
 412                 break;
 413         case IDMAP_CONV_NAMETOID:
 414                 /* Did we match the current upcall? */
 415                 if (im->im_conv == IDMAP_CONV_NAMETOID
 416                                 && im->im_type == im_in.im_type
 417                                 && strnlen(im->im_name, IDMAP_NAMESZ) == namelen_in
 418                                 && memcmp(im->im_name, im_in.im_name, namelen_in) == 0) {
 419                         im->im_id = im_in.im_id;
 420                         wake_up(&idmap->idmap_wq);
 421                 }
 422                 he = idmap_alloc_name(h, im_in.im_name, namelen_in);
 423                 break;
 424         default:
 425                 goto out;
 426         }
 427
 428         /* If the entry is valid, also copy it to the cache */
 429         if (he != NULL)
 430                 idmap_update_entry(he, im_in.im_name, namelen_in, im_in.im_id);
 431         ret = mlen;
 432 out:
 433         up(&idmap->idmap_im_lock);
 434         return ret;
 435 }
 436
 437 static void
 438 idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 439 {
 440         struct idmap_msg *im = msg->data;
 441         struct idmap *idmap = container_of(im, struct idmap, idmap_im);
 442
 443         if (msg->errno >= 0)
 444                 return;
 445         down(&idmap->idmap_im_lock);
 446         im->im_status = IDMAP_STATUS_LOOKUPFAIL;
 447         wake_up(&idmap->idmap_wq);
 448         up(&idmap->idmap_im_lock);
 449 }
 450
 451 /*
 452  * Fowler/Noll/Vo hash
 453  *    http://www.isthe.com/chongo/tech/comp/fnv/
 454  */
 455
 456 #define FNV_P_32 ((unsigned int)0x01000193) /* 16777619 */
 457 #define FNV_1_32 ((unsigned int)0x811c9dc5) /* 2166136261 */
 458
 459 static unsigned int fnvhash32(const void *buf, size_t buflen)
 460 {
 461         const unsigned char *p, *end = (const unsigned char *)buf + buflen;
 462         unsigned int hash = FNV_1_32;
 463
 464         for (p = buf; p < end; p++) {
 465                 hash *= FNV_P_32;
 466                 hash ^= (unsigned int)*p;
 467         }
 468
 469         return (hash);
 470 }
 471
 472 int nfs_map_name_to_uid(struct nfs4_client *clp, const char *name, size_t namelen, __u32 *uid)
 473 {
 474         struct idmap *idmap = clp->cl_idmap;
 475
 476         return nfs_idmap_id(idmap, &idmap->idmap_user_hash, name, namelen, uid);
 477 }
 478
 479 int nfs_map_group_to_gid(struct nfs4_client *clp, const char *name, size_t namelen, __u32 *uid)
 480 {
 481         struct idmap *idmap = clp->cl_idmap;
 482
 483         return nfs_idmap_id(idmap, &idmap->idmap_group_hash, name, namelen, uid);
 484 }
 485
 486 int nfs_map_uid_to_name(struct nfs4_client *clp, __u32 uid, char *buf)
 487 {
 488         struct idmap *idmap = clp->cl_idmap;
 489
 490         return nfs_idmap_name(idmap, &idmap->idmap_user_hash, uid, buf);
 491 }
 492 int nfs_map_gid_to_group(struct nfs4_client *clp, __u32 uid, char *buf)
 493 {
 494         struct idmap *idmap = clp->cl_idmap;
 495
 496         return nfs_idmap_name(idmap, &idmap->idmap_group_hash, uid, buf);
 497 }
 498