SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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 #include <net/netlink.h>
  22 #include <net/genetlink.h>
  23
  24 static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
  25                                      qid_t id)
  26 {
  27         switch (cmd) {
  28         /* these commands do not require any special privilegues */
  29         case Q_GETFMT:
  30         case Q_SYNC:
  31         case Q_GETINFO:
  32         case Q_XGETQSTAT:
  33         case Q_XQUOTASYNC:
  34                 break;
  35         /* allow to query information for dquots we "own" */
  36         case Q_GETQUOTA:
  37         case Q_XGETQUOTA:
  38                 if ((type == USRQUOTA && current_euid() == id) ||
  39                     (type == GRPQUOTA && in_egroup_p(id)))
  40                         break;
  41                 /*FALLTHROUGH*/
  42         default:
  43                 if (!capable(CAP_SYS_ADMIN))
  44                         return -EPERM;
  45         }
  46
  47         return security_quotactl(cmd, type, id, sb);
  48 }
  49
  50 #ifdef CONFIG_QUOTA
  51 void sync_quota_sb(struct super_block *sb, int type)
  52 {
  53         int cnt;
  54
  55         if (!sb->s_qcop->quota_sync)
  56                 return;
  57
  58         sb->s_qcop->quota_sync(sb, type);
  59
  60         if (sb_dqopt(sb)->flags & DQUOT_QUOTA_SYS_FILE)
  61                 return;
  62         /* This is not very clever (and fast) but currently I don't know about
  63          * any other simple way of getting quota data to disk and we must get
  64          * them there for userspace to be visible... */
  65         if (sb->s_op->sync_fs)
  66                 sb->s_op->sync_fs(sb, 1);
  67         sync_blockdev(sb->s_bdev);
  68
  69         /*
  70          * Now when everything is written we can discard the pagecache so
  71          * that userspace sees the changes.
  72          */
  73         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
  74         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
  75                 if (type != -1 && cnt != type)
  76                         continue;
  77                 if (!sb_has_quota_active(sb, cnt))
  78                         continue;
  79                 mutex_lock_nested(&sb_dqopt(sb)->files[cnt]->i_mutex,
  80                                   I_MUTEX_QUOTA);
  81                 truncate_inode_pages(&sb_dqopt(sb)->files[cnt]->i_data, 0);
  82                 mutex_unlock(&sb_dqopt(sb)->files[cnt]->i_mutex);
  83         }
  84         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
  85 }
  86 #endif
  87
  88 static int quota_sync_all(int type)
  89 {
  90         struct super_block *sb;
  91         int cnt;
  92         int ret;
  93
  94         if (type >= MAXQUOTAS)
  95                 return -EINVAL;
  96         ret = security_quotactl(Q_SYNC, type, 0, NULL);
  97         if (ret)
  98                 return ret;
  99
 100         spin_lock(&sb_lock);
 101 restart:
 102         list_for_each_entry(sb, &super_blocks, s_list) {
 103                 /* This test just improves performance so it needn't be
 104                  * reliable... */
 105                 for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
 106                         if (type != -1 && type != cnt)
 107                                 continue;
 108                         if (!sb_has_quota_active(sb, cnt))
 109                                 continue;
 110                         if (!info_dirty(&sb_dqopt(sb)->info[cnt]) &&
 111                            list_empty(&sb_dqopt(sb)->info[cnt].dqi_dirty_list))
 112                                 continue;
 113                         break;
 114                 }
 115                 if (cnt == MAXQUOTAS)
 116                         continue;
 117                 sb->s_count++;
 118                 spin_unlock(&sb_lock);
 119                 down_read(&sb->s_umount);
 120                 if (sb->s_root)
 121                         sync_quota_sb(sb, type);
 122                 up_read(&sb->s_umount);
 123                 spin_lock(&sb_lock);
 124                 if (__put_super_and_need_restart(sb))
 125                         goto restart;
 126         }
 127         spin_unlock(&sb_lock);
 128
 129         return 0;
 130 }
 131
 132 static int quota_quotaon(struct super_block *sb, int type, int cmd, qid_t id,
 133                          void __user *addr)
 134 {
 135         char *pathname;
 136         int ret = -ENOSYS;
 137
 138         pathname = getname(addr);
 139         if (IS_ERR(pathname))
 140                 return PTR_ERR(pathname);
 141         if (sb->s_qcop->quota_on)
 142                 ret = sb->s_qcop->quota_on(sb, type, id, pathname, 0);
 143         putname(pathname);
 144         return ret;
 145 }
 146
 147 static int quota_getfmt(struct super_block *sb, int type, void __user *addr)
 148 {
 149         __u32 fmt;
 150
 151         down_read(&sb_dqopt(sb)->dqptr_sem);
 152         if (!sb_has_quota_active(sb, type)) {
 153                 up_read(&sb_dqopt(sb)->dqptr_sem);
 154                 return -ESRCH;
 155         }
 156         fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
 157         up_read(&sb_dqopt(sb)->dqptr_sem);
 158         if (copy_to_user(addr, &fmt, sizeof(fmt)))
 159                 return -EFAULT;
 160         return 0;
 161 }
 162
 163 static int quota_getinfo(struct super_block *sb, int type, void __user *addr)
 164 {
 165         struct if_dqinfo info;
 166         int ret;
 167
 168         if (!sb_has_quota_active(sb, type))
 169                 return -ESRCH;
 170         if (!sb->s_qcop->get_info)
 171                 return -ENOSYS;
 172         ret = sb->s_qcop->get_info(sb, type, &info);
 173         if (!ret && copy_to_user(addr, &info, sizeof(info)))
 174                 return -EFAULT;
 175         return ret;
 176 }
 177
 178 static int quota_setinfo(struct super_block *sb, int type, void __user *addr)
 179 {
 180         struct if_dqinfo info;
 181
 182         if (copy_from_user(&info, addr, sizeof(info)))
 183                 return -EFAULT;
 184         if (!sb_has_quota_active(sb, type))
 185                 return -ESRCH;
 186         if (!sb->s_qcop->set_info)
 187                 return -ENOSYS;
 188         return sb->s_qcop->set_info(sb, type, &info);
 189 }
 190
 191 static int quota_getquota(struct super_block *sb, int type, qid_t id,
 192                           void __user *addr)
 193 {
 194         struct if_dqblk idq;
 195         int ret;
 196
 197         if (!sb_has_quota_active(sb, type))
 198                 return -ESRCH;
 199         if (!sb->s_qcop->get_dqblk)
 200                 return -ENOSYS;
 201         ret = sb->s_qcop->get_dqblk(sb, type, id, &idq);
 202         if (ret)
 203                 return ret;
 204         if (copy_to_user(addr, &idq, sizeof(idq)))
 205                 return -EFAULT;
 206         return 0;
 207 }
 208
 209 static int quota_setquota(struct super_block *sb, int type, qid_t id,
 210                           void __user *addr)
 211 {
 212         struct if_dqblk idq;
 213
 214         if (copy_from_user(&idq, addr, sizeof(idq)))
 215                 return -EFAULT;
 216         if (!sb_has_quota_active(sb, type))
 217                 return -ESRCH;
 218         if (!sb->s_qcop->set_dqblk)
 219                 return -ENOSYS;
 220         return sb->s_qcop->set_dqblk(sb, type, id, &idq);
 221 }
 222
 223 static int quota_setxstate(struct super_block *sb, int cmd, void __user *addr)
 224 {
 225         __u32 flags;
 226
 227         if (copy_from_user(&flags, addr, sizeof(flags)))
 228                 return -EFAULT;
 229         if (!sb->s_qcop->set_xstate)
 230                 return -ENOSYS;
 231         return sb->s_qcop->set_xstate(sb, flags, cmd);
 232 }
 233
 234 static int quota_getxstate(struct super_block *sb, void __user *addr)
 235 {
 236         struct fs_quota_stat fqs;
 237         int ret;
 238
 239         if (!sb->s_qcop->get_xstate)
 240                 return -ENOSYS;
 241         ret = sb->s_qcop->get_xstate(sb, &fqs);
 242         if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
 243                 return -EFAULT;
 244         return ret;
 245 }
 246
 247 static int quota_setxquota(struct super_block *sb, int type, qid_t id,
 248                            void __user *addr)
 249 {
 250         struct fs_disk_quota fdq;
 251
 252         if (copy_from_user(&fdq, addr, sizeof(fdq)))
 253                 return -EFAULT;
 254         if (!sb->s_qcop->set_xquota)
 255                 return -ENOSYS;
 256         return sb->s_qcop->set_xquota(sb, type, id, &fdq);
 257 }
 258
 259 static int quota_getxquota(struct super_block *sb, int type, qid_t id,
 260                            void __user *addr)
 261 {
 262         struct fs_disk_quota fdq;
 263         int ret;
 264
 265         if (!sb->s_qcop->get_xquota)
 266                 return -ENOSYS;
 267         ret = sb->s_qcop->get_xquota(sb, type, id, &fdq);
 268         if (!ret && copy_to_user(addr, &fdq, sizeof(fdq)))
 269                 return -EFAULT;
 270         return ret;
 271 }
 272
 273 /* Copy parameters and call proper function */
 274 static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
 275                        void __user *addr)
 276 {
 277         int ret;
 278
 279         if (type >= (XQM_COMMAND(cmd) ? XQM_MAXQUOTAS : MAXQUOTAS))
 280                 return -EINVAL;
 281         if (!sb->s_qcop)
 282                 return -ENOSYS;
 283
 284         ret = check_quotactl_permission(sb, type, cmd, id);
 285         if (ret < 0)
 286                 return ret;
 287
 288         switch (cmd) {
 289         case Q_QUOTAON:
 290                 return quota_quotaon(sb, type, cmd, id, addr);
 291         case Q_QUOTAOFF:
 292                 if (!sb->s_qcop->quota_off)
 293                         return -ENOSYS;
 294                 return sb->s_qcop->quota_off(sb, type, 0);
 295         case Q_GETFMT:
 296                 return quota_getfmt(sb, type, addr);
 297         case Q_GETINFO:
 298                 return quota_getinfo(sb, type, addr);
 299         case Q_SETINFO:
 300                 return quota_setinfo(sb, type, addr);
 301         case Q_GETQUOTA:
 302                 return quota_getquota(sb, type, id, addr);
 303         case Q_SETQUOTA:
 304                 return quota_setquota(sb, type, id, addr);
 305         case Q_SYNC:
 306                 if (!sb->s_qcop->quota_sync)
 307                         return -ENOSYS;
 308                 sync_quota_sb(sb, type);
 309                 return 0;
 310         case Q_XQUOTAON:
 311         case Q_XQUOTAOFF:
 312         case Q_XQUOTARM:
 313                 return quota_setxstate(sb, cmd, addr);
 314         case Q_XGETQSTAT:
 315                 return quota_getxstate(sb, addr);
 316         case Q_XSETQLIM:
 317                 return quota_setxquota(sb, type, id, addr);
 318         case Q_XGETQUOTA:
 319                 return quota_getxquota(sb, type, id, addr);
 320         case Q_XQUOTASYNC:
 321                 if (!sb->s_qcop->quota_sync)
 322                         return -ENOSYS;
 323                 return sb->s_qcop->quota_sync(sb, type);
 324         default:
 325                 return -EINVAL;
 326         }
 327 }
 328
 329 /*
 330  * look up a superblock on which quota ops will be performed
 331  * - use the name of a block device to find the superblock thereon
 332  */
 333 static struct super_block *quotactl_block(const char __user *special)
 334 {
 335 #ifdef CONFIG_BLOCK
 336         struct block_device *bdev;
 337         struct super_block *sb;
 338         char *tmp = getname(special);
 339
 340         if (IS_ERR(tmp))
 341                 return ERR_CAST(tmp);
 342         bdev = lookup_bdev(tmp);
 343         putname(tmp);
 344         if (IS_ERR(bdev))
 345                 return ERR_CAST(bdev);
 346         sb = get_super(bdev);
 347         bdput(bdev);
 348         if (!sb)
 349                 return ERR_PTR(-ENODEV);
 350
 351         return sb;
 352 #else
 353         return ERR_PTR(-ENODEV);
 354 #endif
 355 }
 356
 357 /*
 358  * This is the system call interface. This communicates with
 359  * the user-level programs. Currently this only supports diskquota
 360  * calls. Maybe we need to add the process quotas etc. in the future,
 361  * but we probably should use rlimits for that.
 362  */
 363 SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
 364                 qid_t, id, void __user *, addr)
 365 {
 366         uint cmds, type;
 367         struct super_block *sb = NULL;
 368         int ret;
 369
 370         cmds = cmd >> SUBCMDSHIFT;
 371         type = cmd & SUBCMDMASK;
 372
 373         /*
 374          * As a special case Q_SYNC can be called without a specific device.
 375          * It will iterate all superblocks that have quota enabled and call
 376          * the sync action on each of them.
 377          */
 378         if (!special) {
 379                 if (cmds == Q_SYNC)
 380                         return quota_sync_all(type);
 381                 return -ENODEV;
 382         }
 383
 384         sb = quotactl_block(special);
 385         if (IS_ERR(sb))
 386                 return PTR_ERR(sb);
 387
 388         ret = do_quotactl(sb, type, cmds, id, addr);
 389
 390         drop_super(sb);
 391         return ret;
 392 }
 393
 394 #if defined(CONFIG_COMPAT_FOR_U64_ALIGNMENT)
 395 /*
 396  * This code works only for 32 bit quota tools over 64 bit OS (x86_64, ia64)
 397  * and is necessary due to alignment problems.
 398  */
 399 struct compat_if_dqblk {
 400         compat_u64 dqb_bhardlimit;
 401         compat_u64 dqb_bsoftlimit;
 402         compat_u64 dqb_curspace;
 403         compat_u64 dqb_ihardlimit;
 404         compat_u64 dqb_isoftlimit;
 405         compat_u64 dqb_curinodes;
 406         compat_u64 dqb_btime;
 407         compat_u64 dqb_itime;
 408         compat_uint_t dqb_valid;
 409 };
 410
 411 /* XFS structures */
 412 struct compat_fs_qfilestat {
 413         compat_u64 dqb_bhardlimit;
 414         compat_u64 qfs_nblks;
 415         compat_uint_t qfs_nextents;
 416 };
 417
 418 struct compat_fs_quota_stat {
 419         __s8            qs_version;
 420         __u16           qs_flags;
 421         __s8            qs_pad;
 422         struct compat_fs_qfilestat      qs_uquota;
 423         struct compat_fs_qfilestat      qs_gquota;
 424         compat_uint_t   qs_incoredqs;
 425         compat_int_t    qs_btimelimit;
 426         compat_int_t    qs_itimelimit;
 427         compat_int_t    qs_rtbtimelimit;
 428         __u16           qs_bwarnlimit;
 429         __u16           qs_iwarnlimit;
 430 };
 431
 432 asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
 433                                                 qid_t id, void __user *addr)
 434 {
 435         unsigned int cmds;
 436         struct if_dqblk __user *dqblk;
 437         struct compat_if_dqblk __user *compat_dqblk;
 438         struct fs_quota_stat __user *fsqstat;
 439         struct compat_fs_quota_stat __user *compat_fsqstat;
 440         compat_uint_t data;
 441         u16 xdata;
 442         long ret;
 443
 444         cmds = cmd >> SUBCMDSHIFT;
 445
 446         switch (cmds) {
 447         case Q_GETQUOTA:
 448                 dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
 449                 compat_dqblk = addr;
 450                 ret = sys_quotactl(cmd, special, id, dqblk);
 451                 if (ret)
 452                         break;
 453                 if (copy_in_user(compat_dqblk, dqblk, sizeof(*compat_dqblk)) ||
 454                         get_user(data, &dqblk->dqb_valid) ||
 455                         put_user(data, &compat_dqblk->dqb_valid))
 456                         ret = -EFAULT;
 457                 break;
 458         case Q_SETQUOTA:
 459                 dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
 460                 compat_dqblk = addr;
 461                 ret = -EFAULT;
 462                 if (copy_in_user(dqblk, compat_dqblk, sizeof(*compat_dqblk)) ||
 463                         get_user(data, &compat_dqblk->dqb_valid) ||
 464                         put_user(data, &dqblk->dqb_valid))
 465                         break;
 466                 ret = sys_quotactl(cmd, special, id, dqblk);
 467                 break;
 468         case Q_XGETQSTAT:
 469                 fsqstat = compat_alloc_user_space(sizeof(struct fs_quota_stat));
 470                 compat_fsqstat = addr;
 471                 ret = sys_quotactl(cmd, special, id, fsqstat);
 472                 if (ret)
 473                         break;
 474                 ret = -EFAULT;
 475                 /* Copying qs_version, qs_flags, qs_pad */
 476                 if (copy_in_user(compat_fsqstat, fsqstat,
 477                         offsetof(struct compat_fs_quota_stat, qs_uquota)))
 478                         break;
 479                 /* Copying qs_uquota */
 480                 if (copy_in_user(&compat_fsqstat->qs_uquota,
 481                         &fsqstat->qs_uquota,
 482                         sizeof(compat_fsqstat->qs_uquota)) ||
 483                         get_user(data, &fsqstat->qs_uquota.qfs_nextents) ||
 484                         put_user(data, &compat_fsqstat->qs_uquota.qfs_nextents))
 485                         break;
 486                 /* Copying qs_gquota */
 487                 if (copy_in_user(&compat_fsqstat->qs_gquota,
 488                         &fsqstat->qs_gquota,
 489                         sizeof(compat_fsqstat->qs_gquota)) ||
 490                         get_user(data, &fsqstat->qs_gquota.qfs_nextents) ||
 491                         put_user(data, &compat_fsqstat->qs_gquota.qfs_nextents))
 492                         break;
 493                 /* Copying the rest */
 494                 if (copy_in_user(&compat_fsqstat->qs_incoredqs,
 495                         &fsqstat->qs_incoredqs,
 496                         sizeof(struct compat_fs_quota_stat) -
 497                         offsetof(struct compat_fs_quota_stat, qs_incoredqs)) ||
 498                         get_user(xdata, &fsqstat->qs_iwarnlimit) ||
 499                         put_user(xdata, &compat_fsqstat->qs_iwarnlimit))
 500                         break;
 501                 ret = 0;
 502                 break;
 503         default:
 504                 ret = sys_quotactl(cmd, special, id, addr);
 505         }
 506         return ret;
 507 }
 508 #endif
 509
 510
 511 #ifdef CONFIG_QUOTA_NETLINK_INTERFACE
 512
 513 /* Netlink family structure for quota */
 514 static struct genl_family quota_genl_family = {
 515         .id = GENL_ID_GENERATE,
 516         .hdrsize = 0,
 517         .name = "VFS_DQUOT",
 518         .version = 1,
 519         .maxattr = QUOTA_NL_A_MAX,
 520 };
 521
 522 /**
 523  * quota_send_warning - Send warning to userspace about exceeded quota
 524  * @type: The quota type: USRQQUOTA, GRPQUOTA,...
 525  * @id: The user or group id of the quota that was exceeded
 526  * @dev: The device on which the fs is mounted (sb->s_dev)
 527  * @warntype: The type of the warning: QUOTA_NL_...
 528  *
 529  * This can be used by filesystems (including those which don't use
 530  * dquot) to send a message to userspace relating to quota limits.
 531  *
 532  */
 533
 534 void quota_send_warning(short type, unsigned int id, dev_t dev,
 535                         const char warntype)
 536 {
 537         static atomic_t seq;
 538         struct sk_buff *skb;
 539         void *msg_head;
 540         int ret;
 541         int msg_size = 4 * nla_total_size(sizeof(u32)) +
 542                        2 * nla_total_size(sizeof(u64));
 543
 544         /* We have to allocate using GFP_NOFS as we are called from a
 545          * filesystem performing write and thus further recursion into
 546          * the fs to free some data could cause deadlocks. */
 547         skb = genlmsg_new(msg_size, GFP_NOFS);
 548         if (!skb) {
 549                 printk(KERN_ERR
 550                   "VFS: Not enough memory to send quota warning.\n");
 551                 return;
 552         }
 553         msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq),
 554                         &quota_genl_family, 0, QUOTA_NL_C_WARNING);
 555         if (!msg_head) {
 556                 printk(KERN_ERR
 557                   "VFS: Cannot store netlink header in quota warning.\n");
 558                 goto err_out;
 559         }
 560         ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, type);
 561         if (ret)
 562                 goto attr_err_out;
 563         ret = nla_put_u64(skb, QUOTA_NL_A_EXCESS_ID, id);
 564         if (ret)
 565                 goto attr_err_out;
 566         ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype);
 567         if (ret)
 568                 goto attr_err_out;
 569         ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR, MAJOR(dev));
 570         if (ret)
 571                 goto attr_err_out;
 572         ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR, MINOR(dev));
 573         if (ret)
 574                 goto attr_err_out;
 575         ret = nla_put_u64(skb, QUOTA_NL_A_CAUSED_ID, current_uid());
 576         if (ret)
 577                 goto attr_err_out;
 578         genlmsg_end(skb, msg_head);
 579
 580         genlmsg_multicast(skb, 0, quota_genl_family.id, GFP_NOFS);
 581         return;
 582 attr_err_out:
 583         printk(KERN_ERR "VFS: Not enough space to compose quota message!\n");
 584 err_out:
 585         kfree_skb(skb);
 586 }
 587 EXPORT_SYMBOL(quota_send_warning);
 588
 589 static int __init quota_init(void)
 590 {
 591         if (genl_register_family(&quota_genl_family) != 0)
 592                 printk(KERN_ERR
 593                        "VFS: Failed to create quota netlink interface.\n");
 594         return 0;
 595 };
 596
 597 module_init(quota_init);
 598 #endif
 599