block/ioctl.c

   1 #include <linux/capability.h>
   2 #include <linux/blkdev.h>
   3 #include <linux/export.h>
   4 #include <linux/gfp.h>
   5 #include <linux/blkpg.h>
   6 #include <linux/hdreg.h>
   7 #include <linux/backing-dev.h>
   8 #include <linux/fs.h>
   9 #include <linux/blktrace_api.h>
  10 #include <linux/pr.h>
  11 #include <linux/uaccess.h>
  12
  13 static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user *arg)
  14 {
  15         struct block_device *bdevp;
  16         struct gendisk *disk;
  17         struct hd_struct *part, *lpart;
  18         struct blkpg_ioctl_arg a;
  19         struct blkpg_partition p;
  20         struct disk_part_iter piter;
  21         long long start, length;
  22         int partno;
  23
  24         if (!capable(CAP_SYS_ADMIN))
  25                 return -EACCES;
  26         if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
  27                 return -EFAULT;
  28         if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
  29                 return -EFAULT;
  30         disk = bdev->bd_disk;
  31         if (bdev != bdev->bd_contains)
  32                 return -EINVAL;
  33         partno = p.pno;
  34         if (partno <= 0)
  35                 return -EINVAL;
  36         switch (a.op) {
  37                 case BLKPG_ADD_PARTITION:
  38                         start = p.start >> 9;
  39                         length = p.length >> 9;
  40                         /* check for fit in a hd_struct */
  41                         if (sizeof(sector_t) == sizeof(long) &&
  42                             sizeof(long long) > sizeof(long)) {
  43                                 long pstart = start, plength = length;
  44                                 if (pstart != start || plength != length
  45                                     || pstart < 0 || plength < 0 || partno > 65535)
  46                                         return -EINVAL;
  47                         }
  48                         /* check if partition is aligned to blocksize */
  49                         if (p.start & (bdev_logical_block_size(bdev) - 1))
  50                                 return -EINVAL;
  51
  52                         mutex_lock(&bdev->bd_mutex);
  53
  54                         /* overlap? */
  55                         disk_part_iter_init(&piter, disk,
  56                                             DISK_PITER_INCL_EMPTY);
  57                         while ((part = disk_part_iter_next(&piter))) {
  58                                 if (!(start + length <= part->start_sect ||
  59                                       start >= part->start_sect + part->nr_sects)) {
  60                                         disk_part_iter_exit(&piter);
  61                                         mutex_unlock(&bdev->bd_mutex);
  62                                         return -EBUSY;
  63                                 }
  64                         }
  65                         disk_part_iter_exit(&piter);
  66
  67                         /* all seems OK */
  68                         part = add_partition(disk, partno, start, length,
  69                                              ADDPART_FLAG_NONE, NULL);
  70                         mutex_unlock(&bdev->bd_mutex);
  71                         return PTR_ERR_OR_ZERO(part);
  72                 case BLKPG_DEL_PARTITION:
  73                         part = disk_get_part(disk, partno);
  74                         if (!part)
  75                                 return -ENXIO;
  76
  77                         bdevp = bdget(part_devt(part));
  78                         disk_put_part(part);
  79                         if (!bdevp)
  80                                 return -ENOMEM;
  81
  82                         mutex_lock(&bdevp->bd_mutex);
  83                         if (bdevp->bd_openers) {
  84                                 mutex_unlock(&bdevp->bd_mutex);
  85                                 bdput(bdevp);
  86                                 return -EBUSY;
  87                         }
  88                         /* all seems OK */
  89                         fsync_bdev(bdevp);
  90                         invalidate_bdev(bdevp);
  91
  92                         mutex_lock_nested(&bdev->bd_mutex, 1);
  93                         delete_partition(disk, partno);
  94                         mutex_unlock(&bdev->bd_mutex);
  95                         mutex_unlock(&bdevp->bd_mutex);
  96                         bdput(bdevp);
  97
  98                         return 0;
  99                 case BLKPG_RESIZE_PARTITION:
 100                         start = p.start >> 9;
 101                         /* new length of partition in bytes */
 102                         length = p.length >> 9;
 103                         /* check for fit in a hd_struct */
 104                         if (sizeof(sector_t) == sizeof(long) &&
 105                             sizeof(long long) > sizeof(long)) {
 106                                 long pstart = start, plength = length;
 107                                 if (pstart != start || plength != length
 108                                     || pstart < 0 || plength < 0)
 109                                         return -EINVAL;
 110                         }
 111                         part = disk_get_part(disk, partno);
 112                         if (!part)
 113                                 return -ENXIO;
 114                         bdevp = bdget(part_devt(part));
 115                         if (!bdevp) {
 116                                 disk_put_part(part);
 117                                 return -ENOMEM;
 118                         }
 119                         mutex_lock(&bdevp->bd_mutex);
 120                         mutex_lock_nested(&bdev->bd_mutex, 1);
 121                         if (start != part->start_sect) {
 122                                 mutex_unlock(&bdevp->bd_mutex);
 123                                 mutex_unlock(&bdev->bd_mutex);
 124                                 bdput(bdevp);
 125                                 disk_put_part(part);
 126                                 return -EINVAL;
 127                         }
 128                         /* overlap? */
 129                         disk_part_iter_init(&piter, disk,
 130                                             DISK_PITER_INCL_EMPTY);
 131                         while ((lpart = disk_part_iter_next(&piter))) {
 132                                 if (lpart->partno != partno &&
 133                                    !(start + length <= lpart->start_sect ||
 134                                    start >= lpart->start_sect + lpart->nr_sects)
 135                                    ) {
 136                                         disk_part_iter_exit(&piter);
 137                                         mutex_unlock(&bdevp->bd_mutex);
 138                                         mutex_unlock(&bdev->bd_mutex);
 139                                         bdput(bdevp);
 140                                         disk_put_part(part);
 141                                         return -EBUSY;
 142                                 }
 143                         }
 144                         disk_part_iter_exit(&piter);
 145                         part_nr_sects_write(part, (sector_t)length);
 146                         i_size_write(bdevp->bd_inode, p.length);
 147                         mutex_unlock(&bdevp->bd_mutex);
 148                         mutex_unlock(&bdev->bd_mutex);
 149                         bdput(bdevp);
 150                         disk_put_part(part);
 151                         return 0;
 152                 default:
 153                         return -EINVAL;
 154         }
 155 }
 156
 157 /*
 158  * This is an exported API for the block driver, and will not
 159  * acquire bd_mutex. This API should be used in case that
 160  * caller has held bd_mutex already.
 161  */
 162 int __blkdev_reread_part(struct block_device *bdev)
 163 {
 164         struct gendisk *disk = bdev->bd_disk;
 165
 166         if (!disk_part_scan_enabled(disk) || bdev != bdev->bd_contains)
 167                 return -EINVAL;
 168         if (!capable(CAP_SYS_ADMIN))
 169                 return -EACCES;
 170
 171         lockdep_assert_held(&bdev->bd_mutex);
 172
 173         return rescan_partitions(disk, bdev);
 174 }
 175 EXPORT_SYMBOL(__blkdev_reread_part);
 176
 177 /*
 178  * This is an exported API for the block driver, and will
 179  * try to acquire bd_mutex. If bd_mutex has been held already
 180  * in current context, please call __blkdev_reread_part().
 181  *
 182  * Make sure the held locks in current context aren't required
 183  * in open()/close() handler and I/O path for avoiding ABBA deadlock:
 184  * - bd_mutex is held before calling block driver's open/close
 185  *   handler
 186  * - reading partition table may submit I/O to the block device
 187  */
 188 int blkdev_reread_part(struct block_device *bdev)
 189 {
 190         int res;
 191
 192         mutex_lock(&bdev->bd_mutex);
 193         res = __blkdev_reread_part(bdev);
 194         mutex_unlock(&bdev->bd_mutex);
 195
 196         return res;
 197 }
 198 EXPORT_SYMBOL(blkdev_reread_part);
 199
 200 static int blk_ioctl_discard(struct block_device *bdev, fmode_t mode,
 201                 unsigned long arg, unsigned long flags)
 202 {
 203         uint64_t range[2];
 204         uint64_t start, len;
 205
 206         if (!(mode & FMODE_WRITE))
 207                 return -EBADF;
 208
 209         if (copy_from_user(range, (void __user *)arg, sizeof(range)))
 210                 return -EFAULT;
 211
 212         start = range[0];
 213         len = range[1];
 214
 215         if (start & 511)
 216                 return -EINVAL;
 217         if (len & 511)
 218                 return -EINVAL;
 219         start >>= 9;
 220         len >>= 9;
 221
 222         if (start + len > (i_size_read(bdev->bd_inode) >> 9))
 223                 return -EINVAL;
 224         return blkdev_issue_discard(bdev, start, len, GFP_KERNEL, flags);
 225 }
 226
 227 static int blk_ioctl_zeroout(struct block_device *bdev, fmode_t mode,
 228                 unsigned long arg)
 229 {
 230         uint64_t range[2];
 231         struct address_space *mapping;
 232         uint64_t start, end, len;
 233
 234         if (!(mode & FMODE_WRITE))
 235                 return -EBADF;
 236
 237         if (copy_from_user(range, (void __user *)arg, sizeof(range)))
 238                 return -EFAULT;
 239
 240         start = range[0];
 241         len = range[1];
 242         end = start + len - 1;
 243
 244         if (start & 511)
 245                 return -EINVAL;
 246         if (len & 511)
 247                 return -EINVAL;
 248         if (end >= (uint64_t)i_size_read(bdev->bd_inode))
 249                 return -EINVAL;
 250         if (end < start)
 251                 return -EINVAL;
 252
 253         /* Invalidate the page cache, including dirty pages */
 254         mapping = bdev->bd_inode->i_mapping;
 255         truncate_inode_pages_range(mapping, start, end);
 256
 257         return blkdev_issue_zeroout(bdev, start >> 9, len >> 9, GFP_KERNEL,
 258                                     false);
 259 }
 260
 261 static int put_ushort(unsigned long arg, unsigned short val)
 262 {
 263         return put_user(val, (unsigned short __user *)arg);
 264 }
 265
 266 static int put_int(unsigned long arg, int val)
 267 {
 268         return put_user(val, (int __user *)arg);
 269 }
 270
 271 static int put_uint(unsigned long arg, unsigned int val)
 272 {
 273         return put_user(val, (unsigned int __user *)arg);
 274 }
 275
 276 static int put_long(unsigned long arg, long val)
 277 {
 278         return put_user(val, (long __user *)arg);
 279 }
 280
 281 static int put_ulong(unsigned long arg, unsigned long val)
 282 {
 283         return put_user(val, (unsigned long __user *)arg);
 284 }
 285
 286 static int put_u64(unsigned long arg, u64 val)
 287 {
 288         return put_user(val, (u64 __user *)arg);
 289 }
 290
 291 int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
 292                         unsigned cmd, unsigned long arg)
 293 {
 294         struct gendisk *disk = bdev->bd_disk;
 295
 296         if (disk->fops->ioctl)
 297                 return disk->fops->ioctl(bdev, mode, cmd, arg);
 298
 299         return -ENOTTY;
 300 }
 301 /*
 302  * For the record: _GPL here is only because somebody decided to slap it
 303  * on the previous export.  Sheer idiocy, since it wasn't copyrightable
 304  * at all and could be open-coded without any exports by anybody who cares.
 305  */
 306 EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
 307
 308 static int blkdev_pr_register(struct block_device *bdev,
 309                 struct pr_registration __user *arg)
 310 {
 311         const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
 312         struct pr_registration reg;
 313
 314         if (!capable(CAP_SYS_ADMIN))
 315                 return -EPERM;
 316         if (!ops || !ops->pr_register)
 317                 return -EOPNOTSUPP;
 318         if (copy_from_user(&reg, arg, sizeof(reg)))
 319                 return -EFAULT;
 320
 321         if (reg.flags & ~PR_FL_IGNORE_KEY)
 322                 return -EOPNOTSUPP;
 323         return ops->pr_register(bdev, reg.old_key, reg.new_key, reg.flags);
 324 }
 325
 326 static int blkdev_pr_reserve(struct block_device *bdev,
 327                 struct pr_reservation __user *arg)
 328 {
 329         const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
 330         struct pr_reservation rsv;
 331
 332         if (!capable(CAP_SYS_ADMIN))
 333                 return -EPERM;
 334         if (!ops || !ops->pr_reserve)
 335                 return -EOPNOTSUPP;
 336         if (copy_from_user(&rsv, arg, sizeof(rsv)))
 337                 return -EFAULT;
 338
 339         if (rsv.flags & ~PR_FL_IGNORE_KEY)
 340                 return -EOPNOTSUPP;
 341         return ops->pr_reserve(bdev, rsv.key, rsv.type, rsv.flags);
 342 }
 343
 344 static int blkdev_pr_release(struct block_device *bdev,
 345                 struct pr_reservation __user *arg)
 346 {
 347         const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
 348         struct pr_reservation rsv;
 349
 350         if (!capable(CAP_SYS_ADMIN))
 351                 return -EPERM;
 352         if (!ops || !ops->pr_release)
 353                 return -EOPNOTSUPP;
 354         if (copy_from_user(&rsv, arg, sizeof(rsv)))
 355                 return -EFAULT;
 356
 357         if (rsv.flags)
 358                 return -EOPNOTSUPP;
 359         return ops->pr_release(bdev, rsv.key, rsv.type);
 360 }
 361
 362 static int blkdev_pr_preempt(struct block_device *bdev,
 363                 struct pr_preempt __user *arg, bool abort)
 364 {
 365         const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
 366         struct pr_preempt p;
 367
 368         if (!capable(CAP_SYS_ADMIN))
 369                 return -EPERM;
 370         if (!ops || !ops->pr_preempt)
 371                 return -EOPNOTSUPP;
 372         if (copy_from_user(&p, arg, sizeof(p)))
 373                 return -EFAULT;
 374
 375         if (p.flags)
 376                 return -EOPNOTSUPP;
 377         return ops->pr_preempt(bdev, p.old_key, p.new_key, p.type, abort);
 378 }
 379
 380 static int blkdev_pr_clear(struct block_device *bdev,
 381                 struct pr_clear __user *arg)
 382 {
 383         const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
 384         struct pr_clear c;
 385
 386         if (!capable(CAP_SYS_ADMIN))
 387                 return -EPERM;
 388         if (!ops || !ops->pr_clear)
 389                 return -EOPNOTSUPP;
 390         if (copy_from_user(&c, arg, sizeof(c)))
 391                 return -EFAULT;
 392
 393         if (c.flags)
 394                 return -EOPNOTSUPP;
 395         return ops->pr_clear(bdev, c.key);
 396 }
 397
 398 /*
 399  * Is it an unrecognized ioctl? The correct returns are either
 400  * ENOTTY (final) or ENOIOCTLCMD ("I don't know this one, try a
 401  * fallback"). ENOIOCTLCMD gets turned into ENOTTY by the ioctl
 402  * code before returning.
 403  *
 404  * Confused drivers sometimes return EINVAL, which is wrong. It
 405  * means "I understood the ioctl command, but the parameters to
 406  * it were wrong".
 407  *
 408  * We should aim to just fix the broken drivers, the EINVAL case
 409  * should go away.
 410  */
 411 static inline int is_unrecognized_ioctl(int ret)
 412 {
 413         return  ret == -EINVAL ||
 414                 ret == -ENOTTY ||
 415                 ret == -ENOIOCTLCMD;
 416 }
 417
 418 static int blkdev_flushbuf(struct block_device *bdev, fmode_t mode,
 419                 unsigned cmd, unsigned long arg)
 420 {
 421         int ret;
 422
 423         if (!capable(CAP_SYS_ADMIN))
 424                 return -EACCES;
 425
 426         ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 427         if (!is_unrecognized_ioctl(ret))
 428                 return ret;
 429
 430         fsync_bdev(bdev);
 431         invalidate_bdev(bdev);
 432         return 0;
 433 }
 434
 435 static int blkdev_roset(struct block_device *bdev, fmode_t mode,
 436                 unsigned cmd, unsigned long arg)
 437 {
 438         int ret, n;
 439
 440         ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 441         if (!is_unrecognized_ioctl(ret))
 442                 return ret;
 443         if (!capable(CAP_SYS_ADMIN))
 444                 return -EACCES;
 445         if (get_user(n, (int __user *)arg))
 446                 return -EFAULT;
 447         set_device_ro(bdev, n);
 448         return 0;
 449 }
 450
 451 static int blkdev_getgeo(struct block_device *bdev,
 452                 struct hd_geometry __user *argp)
 453 {
 454         struct gendisk *disk = bdev->bd_disk;
 455         struct hd_geometry geo;
 456         int ret;
 457
 458         if (!argp)
 459                 return -EINVAL;
 460         if (!disk->fops->getgeo)
 461                 return -ENOTTY;
 462
 463         /*
 464          * We need to set the startsect first, the driver may
 465          * want to override it.
 466          */
 467         memset(&geo, 0, sizeof(geo));
 468         geo.start = get_start_sect(bdev);
 469         ret = disk->fops->getgeo(bdev, &geo);
 470         if (ret)
 471                 return ret;
 472         if (copy_to_user(argp, &geo, sizeof(geo)))
 473                 return -EFAULT;
 474         return 0;
 475 }
 476
 477 /* set the logical block size */
 478 static int blkdev_bszset(struct block_device *bdev, fmode_t mode,
 479                 int __user *argp)
 480 {
 481         int ret, n;
 482
 483         if (!capable(CAP_SYS_ADMIN))
 484                 return -EACCES;
 485         if (!argp)
 486                 return -EINVAL;
 487         if (get_user(n, argp))
 488                 return -EFAULT;
 489
 490         if (!(mode & FMODE_EXCL)) {
 491                 bdgrab(bdev);
 492                 if (blkdev_get(bdev, mode | FMODE_EXCL, &bdev) < 0)
 493                         return -EBUSY;
 494         }
 495
 496         ret = set_blocksize(bdev, n);
 497         if (!(mode & FMODE_EXCL))
 498                 blkdev_put(bdev, mode | FMODE_EXCL);
 499         return ret;
 500 }
 501
 502 /*
 503  * always keep this in sync with compat_blkdev_ioctl()
 504  */
 505 int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
 506                         unsigned long arg)
 507 {
 508         void __user *argp = (void __user *)arg;
 509         loff_t size;
 510         unsigned int max_sectors;
 511
 512         switch (cmd) {
 513         case BLKFLSBUF:
 514                 return blkdev_flushbuf(bdev, mode, cmd, arg);
 515         case BLKROSET:
 516                 return blkdev_roset(bdev, mode, cmd, arg);
 517         case BLKDISCARD:
 518                 return blk_ioctl_discard(bdev, mode, arg, 0);
 519         case BLKSECDISCARD:
 520                 return blk_ioctl_discard(bdev, mode, arg,
 521                                 BLKDEV_DISCARD_SECURE);
 522         case BLKZEROOUT:
 523                 return blk_ioctl_zeroout(bdev, mode, arg);
 524         case BLKREPORTZONE:
 525                 return blkdev_report_zones_ioctl(bdev, mode, cmd, arg);
 526         case BLKRESETZONE:
 527                 return blkdev_reset_zones_ioctl(bdev, mode, cmd, arg);
 528         case HDIO_GETGEO:
 529                 return blkdev_getgeo(bdev, argp);
 530         case BLKRAGET:
 531         case BLKFRAGET:
 532                 if (!arg)
 533                         return -EINVAL;
 534                 return put_long(arg, (bdev->bd_bdi->ra_pages*PAGE_SIZE) / 512);
 535         case BLKROGET:
 536                 return put_int(arg, bdev_read_only(bdev) != 0);
 537         case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
 538                 return put_int(arg, block_size(bdev));
 539         case BLKSSZGET: /* get block device logical block size */
 540                 return put_int(arg, bdev_logical_block_size(bdev));
 541         case BLKPBSZGET: /* get block device physical block size */
 542                 return put_uint(arg, bdev_physical_block_size(bdev));
 543         case BLKIOMIN:
 544                 return put_uint(arg, bdev_io_min(bdev));
 545         case BLKIOOPT:
 546                 return put_uint(arg, bdev_io_opt(bdev));
 547         case BLKALIGNOFF:
 548                 return put_int(arg, bdev_alignment_offset(bdev));
 549         case BLKDISCARDZEROES:
 550                 return put_uint(arg, bdev_discard_zeroes_data(bdev));
 551         case BLKSECTGET:
 552                 max_sectors = min_t(unsigned int, USHRT_MAX,
 553                                     queue_max_sectors(bdev_get_queue(bdev)));
 554                 return put_ushort(arg, max_sectors);
 555         case BLKROTATIONAL:
 556                 return put_ushort(arg, !blk_queue_nonrot(bdev_get_queue(bdev)));
 557         case BLKRASET:
 558         case BLKFRASET:
 559                 if(!capable(CAP_SYS_ADMIN))
 560                         return -EACCES;
 561                 bdev->bd_bdi->ra_pages = (arg * 512) / PAGE_SIZE;
 562                 return 0;
 563         case BLKBSZSET:
 564                 return blkdev_bszset(bdev, mode, argp);
 565         case BLKPG:
 566                 return blkpg_ioctl(bdev, argp);
 567         case BLKRRPART:
 568                 return blkdev_reread_part(bdev);
 569         case BLKGETSIZE:
 570                 size = i_size_read(bdev->bd_inode);
 571                 if ((size >> 9) > ~0UL)
 572                         return -EFBIG;
 573                 return put_ulong(arg, size >> 9);
 574         case BLKGETSIZE64:
 575                 return put_u64(arg, i_size_read(bdev->bd_inode));
 576         case BLKTRACESTART:
 577         case BLKTRACESTOP:
 578         case BLKTRACESETUP:
 579         case BLKTRACETEARDOWN:
 580                 return blk_trace_ioctl(bdev, cmd, argp);
 581         case IOC_PR_REGISTER:
 582                 return blkdev_pr_register(bdev, argp);
 583         case IOC_PR_RESERVE:
 584                 return blkdev_pr_reserve(bdev, argp);
 585         case IOC_PR_RELEASE:
 586                 return blkdev_pr_release(bdev, argp);
 587         case IOC_PR_PREEMPT:
 588                 return blkdev_pr_preempt(bdev, argp, false);
 589         case IOC_PR_PREEMPT_ABORT:
 590                 return blkdev_pr_preempt(bdev, argp, true);
 591         case IOC_PR_CLEAR:
 592                 return blkdev_pr_clear(bdev, argp);
 593         default:
 594                 return __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 595         }
 596 }
 597 EXPORT_SYMBOL_GPL(blkdev_ioctl);