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