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   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
  23 static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
  24                                      qid_t id)
  25 {
  26         switch (cmd) {
  27         /* these commands do not require any special privilegues */
  28         case Q_GETFMT:
  29         case Q_SYNC:
  30         case Q_GETINFO:
  31         case Q_XGETQSTAT:
  32         case Q_XQUOTASYNC:
  33                 break;
  34         /* allow to query information for dquots we "own" */
  35         case Q_GETQUOTA:
  36         case Q_XGETQUOTA:
  37                 if ((type == USRQUOTA && current_euid() == id) ||
  38                     (type == GRPQUOTA && in_egroup_p(id)))
  39                         break;
  40                 /*FALLTHROUGH*/
  41         default:
  42                 if (!capable(CAP_SYS_ADMIN))
  43                         return -EPERM;
  44         }
  45
  46         return security_quotactl(cmd, type, id, sb);
  47 }
  48
  49 static int quota_sync_all(int type)
  50 {
  51         struct super_block *sb;
  52         int ret;
  53
  54         if (type >= MAXQUOTAS)
  55                 return -EINVAL;
  56         ret = security_quotactl(Q_SYNC, type, 0, NULL);
  57         if (ret)
  58                 return ret;
  59
  60         spin_lock(&sb_lock);
  61 restart:
  62         list_for_each_entry(sb, &super_blocks, s_list) {
  63                 if (!sb->s_qcop || !sb->s_qcop->quota_sync)
  64                         continue;
  65
  66                 sb->s_count++;
  67                 spin_unlock(&sb_lock);
  68                 down_read(&sb->s_umount);
  69                 if (sb->s_root)
  70                         sb->s_qcop->quota_sync(sb, type, 1);
  71                 up_read(&sb->s_umount);
  72                 spin_lock(&sb_lock);
  73                 if (__put_super_and_need_restart(sb))
  74                         goto restart;
  75         }
  76         spin_unlock(&sb_lock);
  77
  78         return 0;
  79 }
  80
  81 static int quota_quotaon(struct super_block *sb, int type, int cmd, qid_t id,
  82                          void __user *addr)
  83 {
  84         char *pathname;
  85         int ret = -ENOSYS;
  86
  87         pathname = getname(addr);
  88         if (IS_ERR(pathname))
  89                 return PTR_ERR(pathname);
  90         if (sb->s_qcop->quota_on)
  91                 ret = sb->s_qcop->quota_on(sb, type, id, pathname, 0);
  92         putname(pathname);
  93         return ret;
  94 }
  95
  96 static int quota_getfmt(struct super_block *sb, int type, void __user *addr)
  97 {
  98         __u32 fmt;
  99
 100         down_read(&sb_dqopt(sb)->dqptr_sem);
 101         if (!sb_has_quota_active(sb, type)) {
 102                 up_read(&sb_dqopt(sb)->dqptr_sem);
 103                 return -ESRCH;
 104         }
 105         fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
 106         up_read(&sb_dqopt(sb)->dqptr_sem);
 107         if (copy_to_user(addr, &fmt, sizeof(fmt)))
 108                 return -EFAULT;
 109         return 0;
 110 }
 111
 112 static int quota_getinfo(struct super_block *sb, int type, void __user *addr)
 113 {
 114         struct if_dqinfo info;
 115         int ret;
 116
 117         if (!sb_has_quota_active(sb, type))
 118                 return -ESRCH;
 119         if (!sb->s_qcop->get_info)
 120                 return -ENOSYS;
 121         ret = sb->s_qcop->get_info(sb, type, &info);
 122         if (!ret && copy_to_user(addr, &info, sizeof(info)))
 123                 return -EFAULT;
 124         return ret;
 125 }
 126
 127 static int quota_setinfo(struct super_block *sb, int type, void __user *addr)
 128 {
 129         struct if_dqinfo info;
 130
 131         if (copy_from_user(&info, addr, sizeof(info)))
 132                 return -EFAULT;
 133         if (!sb_has_quota_active(sb, type))
 134                 return -ESRCH;
 135         if (!sb->s_qcop->set_info)
 136                 return -ENOSYS;
 137         return sb->s_qcop->set_info(sb, type, &info);
 138 }
 139
 140 static int quota_getquota(struct super_block *sb, int type, qid_t id,
 141                           void __user *addr)
 142 {
 143         struct if_dqblk idq;
 144         int ret;
 145
 146         if (!sb_has_quota_active(sb, type))
 147                 return -ESRCH;
 148         if (!sb->s_qcop->get_dqblk)
 149                 return -ENOSYS;
 150         ret = sb->s_qcop->get_dqblk(sb, type, id, &idq);
 151         if (ret)
 152                 return ret;
 153         if (copy_to_user(addr, &idq, sizeof(idq)))
 154                 return -EFAULT;
 155         return 0;
 156 }
 157
 158 static int quota_setquota(struct super_block *sb, int type, qid_t id,
 159                           void __user *addr)
 160 {
 161         struct if_dqblk idq;
 162
 163         if (copy_from_user(&idq, addr, sizeof(idq)))
 164                 return -EFAULT;
 165         if (!sb_has_quota_active(sb, type))
 166                 return -ESRCH;
 167         if (!sb->s_qcop->set_dqblk)
 168                 return -ENOSYS;
 169         return sb->s_qcop->set_dqblk(sb, type, id, &idq);
 170 }
 171
 172 static int quota_setxstate(struct super_block *sb, int cmd, void __user *addr)
 173 {
 174         __u32 flags;
 175
 176         if (copy_from_user(&flags, addr, sizeof(flags)))
 177                 return -EFAULT;
 178         if (!sb->s_qcop->set_xstate)
 179                 return -ENOSYS;
 180         return sb->s_qcop->set_xstate(sb, flags, cmd);
 181 }
 182
 183 static int quota_getxstate(struct super_block *sb, void __user *addr)
 184 {
 185         struct fs_quota_stat fqs;
 186         int ret;
 187
 188         if (!sb->s_qcop->get_xstate)
 189                 return -ENOSYS;
 190         ret = sb->s_qcop->get_xstate(sb, &fqs);
 191         if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
 192                 return -EFAULT;
 193         return ret;
 194 }
 195
 196 static int quota_setxquota(struct super_block *sb, int type, qid_t id,
 197                            void __user *addr)
 198 {
 199         struct fs_disk_quota fdq;
 200
 201         if (copy_from_user(&fdq, addr, sizeof(fdq)))
 202                 return -EFAULT;
 203         if (!sb->s_qcop->set_xquota)
 204                 return -ENOSYS;
 205         return sb->s_qcop->set_xquota(sb, type, id, &fdq);
 206 }
 207
 208 static int quota_getxquota(struct super_block *sb, int type, qid_t id,
 209                            void __user *addr)
 210 {
 211         struct fs_disk_quota fdq;
 212         int ret;
 213
 214         if (!sb->s_qcop->get_xquota)
 215                 return -ENOSYS;
 216         ret = sb->s_qcop->get_xquota(sb, type, id, &fdq);
 217         if (!ret && copy_to_user(addr, &fdq, sizeof(fdq)))
 218                 return -EFAULT;
 219         return ret;
 220 }
 221
 222 /* Copy parameters and call proper function */
 223 static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
 224                        void __user *addr)
 225 {
 226         int ret;
 227
 228         if (type >= (XQM_COMMAND(cmd) ? XQM_MAXQUOTAS : MAXQUOTAS))
 229                 return -EINVAL;
 230         if (!sb->s_qcop)
 231                 return -ENOSYS;
 232
 233         ret = check_quotactl_permission(sb, type, cmd, id);
 234         if (ret < 0)
 235                 return ret;
 236
 237         switch (cmd) {
 238         case Q_QUOTAON:
 239                 return quota_quotaon(sb, type, cmd, id, addr);
 240         case Q_QUOTAOFF:
 241                 if (!sb->s_qcop->quota_off)
 242                         return -ENOSYS;
 243                 return sb->s_qcop->quota_off(sb, type, 0);
 244         case Q_GETFMT:
 245                 return quota_getfmt(sb, type, addr);
 246         case Q_GETINFO:
 247                 return quota_getinfo(sb, type, addr);
 248         case Q_SETINFO:
 249                 return quota_setinfo(sb, type, addr);
 250         case Q_GETQUOTA:
 251                 return quota_getquota(sb, type, id, addr);
 252         case Q_SETQUOTA:
 253                 return quota_setquota(sb, type, id, addr);
 254         case Q_SYNC:
 255                 if (!sb->s_qcop->quota_sync)
 256                         return -ENOSYS;
 257                 return sb->s_qcop->quota_sync(sb, type, 1);
 258         case Q_XQUOTAON:
 259         case Q_XQUOTAOFF:
 260         case Q_XQUOTARM:
 261                 return quota_setxstate(sb, cmd, addr);
 262         case Q_XGETQSTAT:
 263                 return quota_getxstate(sb, addr);
 264         case Q_XSETQLIM:
 265                 return quota_setxquota(sb, type, id, addr);
 266         case Q_XGETQUOTA:
 267                 return quota_getxquota(sb, type, id, addr);
 268         case Q_XQUOTASYNC:
 269                 /* caller already holds s_umount */
 270                 if (sb->s_flags & MS_RDONLY)
 271                         return -EROFS;
 272                 writeback_inodes_sb(sb);
 273                 return 0;
 274         default:
 275                 return -EINVAL;
 276         }
 277 }
 278
 279 /*
 280  * look up a superblock on which quota ops will be performed
 281  * - use the name of a block device to find the superblock thereon
 282  */
 283 static struct super_block *quotactl_block(const char __user *special)
 284 {
 285 #ifdef CONFIG_BLOCK
 286         struct block_device *bdev;
 287         struct super_block *sb;
 288         char *tmp = getname(special);
 289
 290         if (IS_ERR(tmp))
 291                 return ERR_CAST(tmp);
 292         bdev = lookup_bdev(tmp);
 293         putname(tmp);
 294         if (IS_ERR(bdev))
 295                 return ERR_CAST(bdev);
 296         sb = get_super(bdev);
 297         bdput(bdev);
 298         if (!sb)
 299                 return ERR_PTR(-ENODEV);
 300
 301         return sb;
 302 #else
 303         return ERR_PTR(-ENODEV);
 304 #endif
 305 }
 306
 307 /*
 308  * This is the system call interface. This communicates with
 309  * the user-level programs. Currently this only supports diskquota
 310  * calls. Maybe we need to add the process quotas etc. in the future,
 311  * but we probably should use rlimits for that.
 312  */
 313 SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
 314                 qid_t, id, void __user *, addr)
 315 {
 316         uint cmds, type;
 317         struct super_block *sb = NULL;
 318         int ret;
 319
 320         cmds = cmd >> SUBCMDSHIFT;
 321         type = cmd & SUBCMDMASK;
 322
 323         /*
 324          * As a special case Q_SYNC can be called without a specific device.
 325          * It will iterate all superblocks that have quota enabled and call
 326          * the sync action on each of them.
 327          */
 328         if (!special) {
 329                 if (cmds == Q_SYNC)
 330                         return quota_sync_all(type);
 331                 return -ENODEV;
 332         }
 333
 334         sb = quotactl_block(special);
 335         if (IS_ERR(sb))
 336                 return PTR_ERR(sb);
 337
 338         ret = do_quotactl(sb, type, cmds, id, addr);
 339
 340         drop_super(sb);
 341         return ret;
 342 }
 343
 344 #if defined(CONFIG_COMPAT_FOR_U64_ALIGNMENT)
 345 /*
 346  * This code works only for 32 bit quota tools over 64 bit OS (x86_64, ia64)
 347  * and is necessary due to alignment problems.
 348  */
 349 struct compat_if_dqblk {
 350         compat_u64 dqb_bhardlimit;
 351         compat_u64 dqb_bsoftlimit;
 352         compat_u64 dqb_curspace;
 353         compat_u64 dqb_ihardlimit;
 354         compat_u64 dqb_isoftlimit;
 355         compat_u64 dqb_curinodes;
 356         compat_u64 dqb_btime;
 357         compat_u64 dqb_itime;
 358         compat_uint_t dqb_valid;
 359 };
 360
 361 /* XFS structures */
 362 struct compat_fs_qfilestat {
 363         compat_u64 dqb_bhardlimit;
 364         compat_u64 qfs_nblks;
 365         compat_uint_t qfs_nextents;
 366 };
 367
 368 struct compat_fs_quota_stat {
 369         __s8            qs_version;
 370         __u16           qs_flags;
 371         __s8            qs_pad;
 372         struct compat_fs_qfilestat      qs_uquota;
 373         struct compat_fs_qfilestat      qs_gquota;
 374         compat_uint_t   qs_incoredqs;
 375         compat_int_t    qs_btimelimit;
 376         compat_int_t    qs_itimelimit;
 377         compat_int_t    qs_rtbtimelimit;
 378         __u16           qs_bwarnlimit;
 379         __u16           qs_iwarnlimit;
 380 };
 381
 382 asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
 383                                                 qid_t id, void __user *addr)
 384 {
 385         unsigned int cmds;
 386         struct if_dqblk __user *dqblk;
 387         struct compat_if_dqblk __user *compat_dqblk;
 388         struct fs_quota_stat __user *fsqstat;
 389         struct compat_fs_quota_stat __user *compat_fsqstat;
 390         compat_uint_t data;
 391         u16 xdata;
 392         long ret;
 393
 394         cmds = cmd >> SUBCMDSHIFT;
 395
 396         switch (cmds) {
 397         case Q_GETQUOTA:
 398                 dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
 399                 compat_dqblk = addr;
 400                 ret = sys_quotactl(cmd, special, id, dqblk);
 401                 if (ret)
 402                         break;
 403                 if (copy_in_user(compat_dqblk, dqblk, sizeof(*compat_dqblk)) ||
 404                         get_user(data, &dqblk->dqb_valid) ||
 405                         put_user(data, &compat_dqblk->dqb_valid))
 406                         ret = -EFAULT;
 407                 break;
 408         case Q_SETQUOTA:
 409                 dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
 410                 compat_dqblk = addr;
 411                 ret = -EFAULT;
 412                 if (copy_in_user(dqblk, compat_dqblk, sizeof(*compat_dqblk)) ||
 413                         get_user(data, &compat_dqblk->dqb_valid) ||
 414                         put_user(data, &dqblk->dqb_valid))
 415                         break;
 416                 ret = sys_quotactl(cmd, special, id, dqblk);
 417                 break;
 418         case Q_XGETQSTAT:
 419                 fsqstat = compat_alloc_user_space(sizeof(struct fs_quota_stat));
 420                 compat_fsqstat = addr;
 421                 ret = sys_quotactl(cmd, special, id, fsqstat);
 422                 if (ret)
 423                         break;
 424                 ret = -EFAULT;
 425                 /* Copying qs_version, qs_flags, qs_pad */
 426                 if (copy_in_user(compat_fsqstat, fsqstat,
 427                         offsetof(struct compat_fs_quota_stat, qs_uquota)))
 428                         break;
 429                 /* Copying qs_uquota */
 430                 if (copy_in_user(&compat_fsqstat->qs_uquota,
 431                         &fsqstat->qs_uquota,
 432                         sizeof(compat_fsqstat->qs_uquota)) ||
 433                         get_user(data, &fsqstat->qs_uquota.qfs_nextents) ||
 434                         put_user(data, &compat_fsqstat->qs_uquota.qfs_nextents))
 435                         break;
 436                 /* Copying qs_gquota */
 437                 if (copy_in_user(&compat_fsqstat->qs_gquota,
 438                         &fsqstat->qs_gquota,
 439                         sizeof(compat_fsqstat->qs_gquota)) ||
 440                         get_user(data, &fsqstat->qs_gquota.qfs_nextents) ||
 441                         put_user(data, &compat_fsqstat->qs_gquota.qfs_nextents))
 442                         break;
 443                 /* Copying the rest */
 444                 if (copy_in_user(&compat_fsqstat->qs_incoredqs,
 445                         &fsqstat->qs_incoredqs,
 446                         sizeof(struct compat_fs_quota_stat) -
 447                         offsetof(struct compat_fs_quota_stat, qs_incoredqs)) ||
 448                         get_user(xdata, &fsqstat->qs_iwarnlimit) ||
 449                         put_user(xdata, &compat_fsqstat->qs_iwarnlimit))
 450                         break;
 451                 ret = 0;
 452                 break;
 453         default:
 454                 ret = sys_quotactl(cmd, special, id, addr);
 455         }
 456         return ret;
 457 }
 458 #endif