fs/quota/quota.c

   1 /*
   2  * Quota code necessary even when VFS quota support is not compiled
   3  * into the kernel.  The interesting stuff is over in dquot.c, here
   4  * we have symbols for initial quotactl(2) handling, the sysctl(2)
   5  * variables, etc - things needed even when quota support disabled.
   6  */
   7
   8 #include <linux/fs.h>
   9 #include <linux/namei.h>
  10 #include <linux/slab.h>
  11 #include <asm/current.h>
  12 #include <asm/uaccess.h>
  13 #include <linux/compat.h>
  14 #include <linux/kernel.h>
  15 #include <linux/security.h>
  16 #include <linux/syscalls.h>
  17 #include <linux/buffer_head.h>
  18 #include <linux/capability.h>
  19 #include <linux/quotaops.h>
  20 #include <linux/types.h>
  21
  22 /* Check validity of generic quotactl commands */
  23 static int generic_quotactl_valid(struct super_block *sb, int type, int cmd,
  24                                   qid_t id)
  25 {
  26         if (type >= MAXQUOTAS)
  27                 return -EINVAL;
  28         if (!sb && cmd != Q_SYNC)
  29                 return -ENODEV;
  30         /* Is operation supported? */
  31         if (sb && !sb->s_qcop)
  32                 return -ENOSYS;
  33
  34         switch (cmd) {
  35                 case Q_GETFMT:
  36                         break;
  37                 case Q_QUOTAON:
  38                         if (!sb->s_qcop->quota_on)
  39                                 return -ENOSYS;
  40                         break;
  41                 case Q_QUOTAOFF:
  42                         if (!sb->s_qcop->quota_off)
  43                                 return -ENOSYS;
  44                         break;
  45                 case Q_SETINFO:
  46                         if (!sb->s_qcop->set_info)
  47                                 return -ENOSYS;
  48                         break;
  49                 case Q_GETINFO:
  50                         if (!sb->s_qcop->get_info)
  51                                 return -ENOSYS;
  52                         break;
  53                 case Q_SETQUOTA:
  54                         if (!sb->s_qcop->set_dqblk)
  55                                 return -ENOSYS;
  56                         break;
  57                 case Q_GETQUOTA:
  58                         if (!sb->s_qcop->get_dqblk)
  59                                 return -ENOSYS;
  60                         break;
  61                 case Q_SYNC:
  62                         if (sb && !sb->s_qcop->quota_sync)
  63                                 return -ENOSYS;
  64                         break;
  65                 default:
  66                         return -EINVAL;
  67         }
  68
  69         /* Is quota turned on for commands which need it? */
  70         switch (cmd) {
  71                 case Q_GETFMT:
  72                 case Q_GETINFO:
  73                 case Q_SETINFO:
  74                 case Q_SETQUOTA:
  75                 case Q_GETQUOTA:
  76                         /* This is just an informative test so we are satisfied
  77                          * without the lock */
  78                         if (!sb_has_quota_active(sb, type))
  79                                 return -ESRCH;
  80         }
  81
  82         /* Check privileges */
  83         if (cmd == Q_GETQUOTA) {
  84                 if (((type == USRQUOTA && current_euid() != id) ||
  85                      (type == GRPQUOTA && !in_egroup_p(id))) &&
  86                     !capable(CAP_SYS_ADMIN))
  87                         return -EPERM;
  88         }
  89         else if (cmd != Q_GETFMT && cmd != Q_SYNC && cmd != Q_GETINFO)
  90                 if (!capable(CAP_SYS_ADMIN))
  91                         return -EPERM;
  92
  93         return 0;
  94 }
  95
  96 /* Check validity of XFS Quota Manager commands */
  97 static int xqm_quotactl_valid(struct super_block *sb, int type, int cmd,
  98                               qid_t id)
  99 {
 100         if (type >= XQM_MAXQUOTAS)
 101                 return -EINVAL;
 102         if (!sb)
 103                 return -ENODEV;
 104         if (!sb->s_qcop)
 105                 return -ENOSYS;
 106
 107         switch (cmd) {
 108                 case Q_XQUOTAON:
 109                 case Q_XQUOTAOFF:
 110                 case Q_XQUOTARM:
 111                         if (!sb->s_qcop->set_xstate)
 112                                 return -ENOSYS;
 113                         break;
 114                 case Q_XGETQSTAT:
 115                         if (!sb->s_qcop->get_xstate)
 116                                 return -ENOSYS;
 117                         break;
 118                 case Q_XSETQLIM:
 119                         if (!sb->s_qcop->set_xquota)
 120                                 return -ENOSYS;
 121                         break;
 122                 case Q_XGETQUOTA:
 123                         if (!sb->s_qcop->get_xquota)
 124                                 return -ENOSYS;
 125                         break;
 126                 case Q_XQUOTASYNC:
 127                         if (!sb->s_qcop->quota_sync)
 128                                 return -ENOSYS;
 129                         break;
 130                 default:
 131                         return -EINVAL;
 132         }
 133
 134         /* Check privileges */
 135         if (cmd == Q_XGETQUOTA) {
 136                 if (((type == XQM_USRQUOTA && current_euid() != id) ||
 137                      (type == XQM_GRPQUOTA && !in_egroup_p(id))) &&
 138                      !capable(CAP_SYS_ADMIN))
 139                         return -EPERM;
 140         } else if (cmd != Q_XGETQSTAT && cmd != Q_XQUOTASYNC) {
 141                 if (!capable(CAP_SYS_ADMIN))
 142                         return -EPERM;
 143         }
 144
 145         return 0;
 146 }
 147
 148 static int check_quotactl_valid(struct super_block *sb, int type, int cmd,
 149                                 qid_t id)
 150 {
 151         int error;
 152
 153         if (XQM_COMMAND(cmd))
 154                 error = xqm_quotactl_valid(sb, type, cmd, id);
 155         else
 156                 error = generic_quotactl_valid(sb, type, cmd, id);
 157         if (!error)
 158                 error = security_quotactl(cmd, type, id, sb);
 159         return error;
 160 }
 161
 162 static void quota_sync_sb(struct super_block *sb, int type)
 163 {
 164         int cnt;
 165
 166         sb->s_qcop->quota_sync(sb, type);
 167
 168         if (sb_dqopt(sb)->flags & DQUOT_QUOTA_SYS_FILE)
 169                 return;
 170         /* This is not very clever (and fast) but currently I don't know about
 171          * any other simple way of getting quota data to disk and we must get
 172          * them there for userspace to be visible... */
 173         if (sb->s_op->sync_fs)
 174                 sb->s_op->sync_fs(sb, 1);
 175         sync_blockdev(sb->s_bdev);
 176
 177         /*
 178          * Now when everything is written we can discard the pagecache so
 179          * that userspace sees the changes.
 180          */
 181         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
 182         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
 183                 if (type != -1 && cnt != type)
 184                         continue;
 185                 if (!sb_has_quota_active(sb, cnt))
 186                         continue;
 187                 mutex_lock_nested(&sb_dqopt(sb)->files[cnt]->i_mutex,
 188                                   I_MUTEX_QUOTA);
 189                 truncate_inode_pages(&sb_dqopt(sb)->files[cnt]->i_data, 0);
 190                 mutex_unlock(&sb_dqopt(sb)->files[cnt]->i_mutex);
 191         }
 192         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
 193 }
 194
 195 void sync_dquots(struct super_block *sb, int type)
 196 {
 197         int cnt;
 198
 199         if (sb) {
 200                 if (sb->s_qcop->quota_sync)
 201                         quota_sync_sb(sb, type);
 202                 return;
 203         }
 204
 205         spin_lock(&sb_lock);
 206 restart:
 207         list_for_each_entry(sb, &super_blocks, s_list) {
 208                 /* This test just improves performance so it needn't be
 209                  * reliable... */
 210                 for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
 211                         if (type != -1 && type != cnt)
 212                                 continue;
 213                         if (!sb_has_quota_active(sb, cnt))
 214                                 continue;
 215                         if (!info_dirty(&sb_dqopt(sb)->info[cnt]) &&
 216                            list_empty(&sb_dqopt(sb)->info[cnt].dqi_dirty_list))
 217                                 continue;
 218                         break;
 219                 }
 220                 if (cnt == MAXQUOTAS)
 221                         continue;
 222                 sb->s_count++;
 223                 spin_unlock(&sb_lock);
 224                 down_read(&sb->s_umount);
 225                 if (sb->s_root && sb->s_qcop->quota_sync)
 226                         quota_sync_sb(sb, type);
 227                 up_read(&sb->s_umount);
 228                 spin_lock(&sb_lock);
 229                 if (__put_super_and_need_restart(sb))
 230                         goto restart;
 231         }
 232         spin_unlock(&sb_lock);
 233 }
 234
 235 /* Copy parameters and call proper function */
 236 static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
 237                        void __user *addr)
 238 {
 239         int ret;
 240
 241         switch (cmd) {
 242                 case Q_QUOTAON: {
 243                         char *pathname;
 244
 245                         pathname = getname(addr);
 246                         if (IS_ERR(pathname))
 247                                 return PTR_ERR(pathname);
 248                         ret = sb->s_qcop->quota_on(sb, type, id, pathname, 0);
 249                         putname(pathname);
 250                         return ret;
 251                 }
 252                 case Q_QUOTAOFF:
 253                         return sb->s_qcop->quota_off(sb, type, 0);
 254
 255                 case Q_GETFMT: {
 256                         __u32 fmt;
 257
 258                         down_read(&sb_dqopt(sb)->dqptr_sem);
 259                         if (!sb_has_quota_active(sb, type)) {
 260                                 up_read(&sb_dqopt(sb)->dqptr_sem);
 261                                 return -ESRCH;
 262                         }
 263                         fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
 264                         up_read(&sb_dqopt(sb)->dqptr_sem);
 265                         if (copy_to_user(addr, &fmt, sizeof(fmt)))
 266                                 return -EFAULT;
 267                         return 0;
 268                 }
 269                 case Q_GETINFO: {
 270                         struct if_dqinfo info;
 271
 272                         ret = sb->s_qcop->get_info(sb, type, &info);
 273                         if (ret)
 274                                 return ret;
 275                         if (copy_to_user(addr, &info, sizeof(info)))
 276                                 return -EFAULT;
 277                         return 0;
 278                 }
 279                 case Q_SETINFO: {
 280                         struct if_dqinfo info;
 281
 282                         if (copy_from_user(&info, addr, sizeof(info)))
 283                                 return -EFAULT;
 284                         return sb->s_qcop->set_info(sb, type, &info);
 285                 }
 286                 case Q_GETQUOTA: {
 287                         struct if_dqblk idq;
 288
 289                         ret = sb->s_qcop->get_dqblk(sb, type, id, &idq);
 290                         if (ret)
 291                                 return ret;
 292                         if (copy_to_user(addr, &idq, sizeof(idq)))
 293                                 return -EFAULT;
 294                         return 0;
 295                 }
 296                 case Q_SETQUOTA: {
 297                         struct if_dqblk idq;
 298
 299                         if (copy_from_user(&idq, addr, sizeof(idq)))
 300                                 return -EFAULT;
 301                         return sb->s_qcop->set_dqblk(sb, type, id, &idq);
 302                 }
 303                 case Q_SYNC:
 304                         sync_dquots(sb, type);
 305                         return 0;
 306
 307                 case Q_XQUOTAON:
 308                 case Q_XQUOTAOFF:
 309                 case Q_XQUOTARM: {
 310                         __u32 flags;
 311
 312                         if (copy_from_user(&flags, addr, sizeof(flags)))
 313                                 return -EFAULT;
 314                         return sb->s_qcop->set_xstate(sb, flags, cmd);
 315                 }
 316                 case Q_XGETQSTAT: {
 317                         struct fs_quota_stat fqs;
 318
 319                         if ((ret = sb->s_qcop->get_xstate(sb, &fqs)))
 320                                 return ret;
 321                         if (copy_to_user(addr, &fqs, sizeof(fqs)))
 322                                 return -EFAULT;
 323                         return 0;
 324                 }
 325                 case Q_XSETQLIM: {
 326                         struct fs_disk_quota fdq;
 327
 328                         if (copy_from_user(&fdq, addr, sizeof(fdq)))
 329                                 return -EFAULT;
 330                        return sb->s_qcop->set_xquota(sb, type, id, &fdq);
 331                 }
 332                 case Q_XGETQUOTA: {
 333                         struct fs_disk_quota fdq;
 334
 335                         ret = sb->s_qcop->get_xquota(sb, type, id, &fdq);
 336                         if (ret)
 337                                 return ret;
 338                         if (copy_to_user(addr, &fdq, sizeof(fdq)))
 339                                 return -EFAULT;
 340                         return 0;
 341                 }
 342                 case Q_XQUOTASYNC:
 343                         return sb->s_qcop->quota_sync(sb, type);
 344                 /* We never reach here unless validity check is broken */
 345                 default:
 346                         BUG();
 347         }
 348         return 0;
 349 }
 350
 351 /*
 352  * look up a superblock on which quota ops will be performed
 353  * - use the name of a block device to find the superblock thereon
 354  */
 355 static struct super_block *quotactl_block(const char __user *special)
 356 {
 357 #ifdef CONFIG_BLOCK
 358         struct block_device *bdev;
 359         struct super_block *sb;
 360         char *tmp = getname(special);
 361
 362         if (IS_ERR(tmp))
 363                 return ERR_CAST(tmp);
 364         bdev = lookup_bdev(tmp);
 365         putname(tmp);
 366         if (IS_ERR(bdev))
 367                 return ERR_CAST(bdev);
 368         sb = get_super(bdev);
 369         bdput(bdev);
 370         if (!sb)
 371                 return ERR_PTR(-ENODEV);
 372
 373         return sb;
 374 #else
 375         return ERR_PTR(-ENODEV);
 376 #endif
 377 }
 378
 379 /*
 380  * This is the system call interface. This communicates with
 381  * the user-level programs. Currently this only supports diskquota
 382  * calls. Maybe we need to add the process quotas etc. in the future,
 383  * but we probably should use rlimits for that.
 384  */
 385 SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
 386                 qid_t, id, void __user *, addr)
 387 {
 388         uint cmds, type;
 389         struct super_block *sb = NULL;
 390         int ret;
 391
 392         cmds = cmd >> SUBCMDSHIFT;
 393         type = cmd & SUBCMDMASK;
 394
 395         if (cmds != Q_SYNC || special) {
 396                 sb = quotactl_block(special);
 397                 if (IS_ERR(sb))
 398                         return PTR_ERR(sb);
 399         }
 400
 401         ret = check_quotactl_valid(sb, type, cmds, id);
 402         if (ret >= 0)
 403                 ret = do_quotactl(sb, type, cmds, id, addr);
 404         if (sb)
 405                 drop_super(sb);
 406
 407         return ret;
 408 }
 409
 410 #if defined(CONFIG_COMPAT_FOR_U64_ALIGNMENT)
 411 /*
 412  * This code works only for 32 bit quota tools over 64 bit OS (x86_64, ia64)
 413  * and is necessary due to alignment problems.
 414  */
 415 struct compat_if_dqblk {
 416         compat_u64 dqb_bhardlimit;
 417         compat_u64 dqb_bsoftlimit;
 418         compat_u64 dqb_curspace;
 419         compat_u64 dqb_ihardlimit;
 420         compat_u64 dqb_isoftlimit;
 421         compat_u64 dqb_curinodes;
 422         compat_u64 dqb_btime;
 423         compat_u64 dqb_itime;
 424         compat_uint_t dqb_valid;
 425 };
 426
 427 /* XFS structures */
 428 struct compat_fs_qfilestat {
 429         compat_u64 dqb_bhardlimit;
 430         compat_u64 qfs_nblks;
 431         compat_uint_t qfs_nextents;
 432 };
 433
 434 struct compat_fs_quota_stat {
 435         __s8            qs_version;
 436         __u16           qs_flags;
 437         __s8            qs_pad;
 438         struct compat_fs_qfilestat      qs_uquota;
 439         struct compat_fs_qfilestat      qs_gquota;
 440         compat_uint_t   qs_incoredqs;
 441         compat_int_t    qs_btimelimit;
 442         compat_int_t    qs_itimelimit;
 443         compat_int_t    qs_rtbtimelimit;
 444         __u16           qs_bwarnlimit;
 445         __u16           qs_iwarnlimit;
 446 };
 447
 448 asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
 449                                                 qid_t id, void __user *addr)
 450 {
 451         unsigned int cmds;
 452         struct if_dqblk __user *dqblk;
 453         struct compat_if_dqblk __user *compat_dqblk;
 454         struct fs_quota_stat __user *fsqstat;
 455         struct compat_fs_quota_stat __user *compat_fsqstat;
 456         compat_uint_t data;
 457         u16 xdata;
 458         long ret;
 459
 460         cmds = cmd >> SUBCMDSHIFT;
 461
 462         switch (cmds) {
 463         case Q_GETQUOTA:
 464                 dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
 465                 compat_dqblk = addr;
 466                 ret = sys_quotactl(cmd, special, id, dqblk);
 467                 if (ret)
 468                         break;
 469                 if (copy_in_user(compat_dqblk, dqblk, sizeof(*compat_dqblk)) ||
 470                         get_user(data, &dqblk->dqb_valid) ||
 471                         put_user(data, &compat_dqblk->dqb_valid))
 472                         ret = -EFAULT;
 473                 break;
 474         case Q_SETQUOTA:
 475                 dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
 476                 compat_dqblk = addr;
 477                 ret = -EFAULT;
 478                 if (copy_in_user(dqblk, compat_dqblk, sizeof(*compat_dqblk)) ||
 479                         get_user(data, &compat_dqblk->dqb_valid) ||
 480                         put_user(data, &dqblk->dqb_valid))
 481                         break;
 482                 ret = sys_quotactl(cmd, special, id, dqblk);
 483                 break;
 484         case Q_XGETQSTAT:
 485                 fsqstat = compat_alloc_user_space(sizeof(struct fs_quota_stat));
 486                 compat_fsqstat = addr;
 487                 ret = sys_quotactl(cmd, special, id, fsqstat);
 488                 if (ret)
 489                         break;
 490                 ret = -EFAULT;
 491                 /* Copying qs_version, qs_flags, qs_pad */
 492                 if (copy_in_user(compat_fsqstat, fsqstat,
 493                         offsetof(struct compat_fs_quota_stat, qs_uquota)))
 494                         break;
 495                 /* Copying qs_uquota */
 496                 if (copy_in_user(&compat_fsqstat->qs_uquota,
 497                         &fsqstat->qs_uquota,
 498                         sizeof(compat_fsqstat->qs_uquota)) ||
 499                         get_user(data, &fsqstat->qs_uquota.qfs_nextents) ||
 500                         put_user(data, &compat_fsqstat->qs_uquota.qfs_nextents))
 501                         break;
 502                 /* Copying qs_gquota */
 503                 if (copy_in_user(&compat_fsqstat->qs_gquota,
 504                         &fsqstat->qs_gquota,
 505                         sizeof(compat_fsqstat->qs_gquota)) ||
 506                         get_user(data, &fsqstat->qs_gquota.qfs_nextents) ||
 507                         put_user(data, &compat_fsqstat->qs_gquota.qfs_nextents))
 508                         break;
 509                 /* Copying the rest */
 510                 if (copy_in_user(&compat_fsqstat->qs_incoredqs,
 511                         &fsqstat->qs_incoredqs,
 512                         sizeof(struct compat_fs_quota_stat) -
 513                         offsetof(struct compat_fs_quota_stat, qs_incoredqs)) ||
 514                         get_user(xdata, &fsqstat->qs_iwarnlimit) ||
 515                         put_user(xdata, &compat_fsqstat->qs_iwarnlimit))
 516                         break;
 517                 ret = 0;
 518                 break;
 519         default:
 520                 ret = sys_quotactl(cmd, special, id, addr);
 521         }
 522         return ret;
 523 }
 524 #endif