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