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