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