xref: /openbmc/linux/block/ioctl.c (revision 82003e04)
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 <asm/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 
49 			mutex_lock(&bdev->bd_mutex);
50 
51 			/* overlap? */
52 			disk_part_iter_init(&piter, disk,
53 					    DISK_PITER_INCL_EMPTY);
54 			while ((part = disk_part_iter_next(&piter))) {
55 				if (!(start + length <= part->start_sect ||
56 				      start >= part->start_sect + part->nr_sects)) {
57 					disk_part_iter_exit(&piter);
58 					mutex_unlock(&bdev->bd_mutex);
59 					return -EBUSY;
60 				}
61 			}
62 			disk_part_iter_exit(&piter);
63 
64 			/* all seems OK */
65 			part = add_partition(disk, partno, start, length,
66 					     ADDPART_FLAG_NONE, NULL);
67 			mutex_unlock(&bdev->bd_mutex);
68 			return PTR_ERR_OR_ZERO(part);
69 		case BLKPG_DEL_PARTITION:
70 			part = disk_get_part(disk, partno);
71 			if (!part)
72 				return -ENXIO;
73 
74 			bdevp = bdget(part_devt(part));
75 			disk_put_part(part);
76 			if (!bdevp)
77 				return -ENOMEM;
78 
79 			mutex_lock(&bdevp->bd_mutex);
80 			if (bdevp->bd_openers) {
81 				mutex_unlock(&bdevp->bd_mutex);
82 				bdput(bdevp);
83 				return -EBUSY;
84 			}
85 			/* all seems OK */
86 			fsync_bdev(bdevp);
87 			invalidate_bdev(bdevp);
88 
89 			mutex_lock_nested(&bdev->bd_mutex, 1);
90 			delete_partition(disk, partno);
91 			mutex_unlock(&bdev->bd_mutex);
92 			mutex_unlock(&bdevp->bd_mutex);
93 			bdput(bdevp);
94 
95 			return 0;
96 		case BLKPG_RESIZE_PARTITION:
97 			start = p.start >> 9;
98 			/* new length of partition in bytes */
99 			length = p.length >> 9;
100 			/* check for fit in a hd_struct */
101 			if (sizeof(sector_t) == sizeof(long) &&
102 			    sizeof(long long) > sizeof(long)) {
103 				long pstart = start, plength = length;
104 				if (pstart != start || plength != length
105 				    || pstart < 0 || plength < 0)
106 					return -EINVAL;
107 			}
108 			part = disk_get_part(disk, partno);
109 			if (!part)
110 				return -ENXIO;
111 			bdevp = bdget(part_devt(part));
112 			if (!bdevp) {
113 				disk_put_part(part);
114 				return -ENOMEM;
115 			}
116 			mutex_lock(&bdevp->bd_mutex);
117 			mutex_lock_nested(&bdev->bd_mutex, 1);
118 			if (start != part->start_sect) {
119 				mutex_unlock(&bdevp->bd_mutex);
120 				mutex_unlock(&bdev->bd_mutex);
121 				bdput(bdevp);
122 				disk_put_part(part);
123 				return -EINVAL;
124 			}
125 			/* overlap? */
126 			disk_part_iter_init(&piter, disk,
127 					    DISK_PITER_INCL_EMPTY);
128 			while ((lpart = disk_part_iter_next(&piter))) {
129 				if (lpart->partno != partno &&
130 				   !(start + length <= lpart->start_sect ||
131 				   start >= lpart->start_sect + lpart->nr_sects)
132 				   ) {
133 					disk_part_iter_exit(&piter);
134 					mutex_unlock(&bdevp->bd_mutex);
135 					mutex_unlock(&bdev->bd_mutex);
136 					bdput(bdevp);
137 					disk_put_part(part);
138 					return -EBUSY;
139 				}
140 			}
141 			disk_part_iter_exit(&piter);
142 			part_nr_sects_write(part, (sector_t)length);
143 			i_size_write(bdevp->bd_inode, p.length);
144 			mutex_unlock(&bdevp->bd_mutex);
145 			mutex_unlock(&bdev->bd_mutex);
146 			bdput(bdevp);
147 			disk_put_part(part);
148 			return 0;
149 		default:
150 			return -EINVAL;
151 	}
152 }
153 
154 /*
155  * This is an exported API for the block driver, and will not
156  * acquire bd_mutex. This API should be used in case that
157  * caller has held bd_mutex already.
158  */
159 int __blkdev_reread_part(struct block_device *bdev)
160 {
161 	struct gendisk *disk = bdev->bd_disk;
162 
163 	if (!disk_part_scan_enabled(disk) || bdev != bdev->bd_contains)
164 		return -EINVAL;
165 	if (!capable(CAP_SYS_ADMIN))
166 		return -EACCES;
167 
168 	lockdep_assert_held(&bdev->bd_mutex);
169 
170 	return rescan_partitions(disk, bdev);
171 }
172 EXPORT_SYMBOL(__blkdev_reread_part);
173 
174 /*
175  * This is an exported API for the block driver, and will
176  * try to acquire bd_mutex. If bd_mutex has been held already
177  * in current context, please call __blkdev_reread_part().
178  *
179  * Make sure the held locks in current context aren't required
180  * in open()/close() handler and I/O path for avoiding ABBA deadlock:
181  * - bd_mutex is held before calling block driver's open/close
182  *   handler
183  * - reading partition table may submit I/O to the block device
184  */
185 int blkdev_reread_part(struct block_device *bdev)
186 {
187 	int res;
188 
189 	mutex_lock(&bdev->bd_mutex);
190 	res = __blkdev_reread_part(bdev);
191 	mutex_unlock(&bdev->bd_mutex);
192 
193 	return res;
194 }
195 EXPORT_SYMBOL(blkdev_reread_part);
196 
197 static int blk_ioctl_discard(struct block_device *bdev, fmode_t mode,
198 		unsigned long arg, unsigned long flags)
199 {
200 	uint64_t range[2];
201 	uint64_t start, len;
202 
203 	if (!(mode & FMODE_WRITE))
204 		return -EBADF;
205 
206 	if (copy_from_user(range, (void __user *)arg, sizeof(range)))
207 		return -EFAULT;
208 
209 	start = range[0];
210 	len = range[1];
211 
212 	if (start & 511)
213 		return -EINVAL;
214 	if (len & 511)
215 		return -EINVAL;
216 	start >>= 9;
217 	len >>= 9;
218 
219 	if (start + len > (i_size_read(bdev->bd_inode) >> 9))
220 		return -EINVAL;
221 	return blkdev_issue_discard(bdev, start, len, GFP_KERNEL, flags);
222 }
223 
224 static int blk_ioctl_zeroout(struct block_device *bdev, fmode_t mode,
225 		unsigned long arg)
226 {
227 	uint64_t range[2];
228 	struct address_space *mapping;
229 	uint64_t start, end, len;
230 
231 	if (!(mode & FMODE_WRITE))
232 		return -EBADF;
233 
234 	if (copy_from_user(range, (void __user *)arg, sizeof(range)))
235 		return -EFAULT;
236 
237 	start = range[0];
238 	len = range[1];
239 	end = start + len - 1;
240 
241 	if (start & 511)
242 		return -EINVAL;
243 	if (len & 511)
244 		return -EINVAL;
245 	if (end >= (uint64_t)i_size_read(bdev->bd_inode))
246 		return -EINVAL;
247 	if (end < start)
248 		return -EINVAL;
249 
250 	/* Invalidate the page cache, including dirty pages */
251 	mapping = bdev->bd_inode->i_mapping;
252 	truncate_inode_pages_range(mapping, start, end);
253 
254 	return blkdev_issue_zeroout(bdev, start >> 9, len >> 9, GFP_KERNEL,
255 				    false);
256 }
257 
258 static int put_ushort(unsigned long arg, unsigned short val)
259 {
260 	return put_user(val, (unsigned short __user *)arg);
261 }
262 
263 static int put_int(unsigned long arg, int val)
264 {
265 	return put_user(val, (int __user *)arg);
266 }
267 
268 static int put_uint(unsigned long arg, unsigned int val)
269 {
270 	return put_user(val, (unsigned int __user *)arg);
271 }
272 
273 static int put_long(unsigned long arg, long val)
274 {
275 	return put_user(val, (long __user *)arg);
276 }
277 
278 static int put_ulong(unsigned long arg, unsigned long val)
279 {
280 	return put_user(val, (unsigned long __user *)arg);
281 }
282 
283 static int put_u64(unsigned long arg, u64 val)
284 {
285 	return put_user(val, (u64 __user *)arg);
286 }
287 
288 int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
289 			unsigned cmd, unsigned long arg)
290 {
291 	struct gendisk *disk = bdev->bd_disk;
292 
293 	if (disk->fops->ioctl)
294 		return disk->fops->ioctl(bdev, mode, cmd, arg);
295 
296 	return -ENOTTY;
297 }
298 /*
299  * For the record: _GPL here is only because somebody decided to slap it
300  * on the previous export.  Sheer idiocy, since it wasn't copyrightable
301  * at all and could be open-coded without any exports by anybody who cares.
302  */
303 EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
304 
305 static int blkdev_pr_register(struct block_device *bdev,
306 		struct pr_registration __user *arg)
307 {
308 	const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
309 	struct pr_registration reg;
310 
311 	if (!capable(CAP_SYS_ADMIN))
312 		return -EPERM;
313 	if (!ops || !ops->pr_register)
314 		return -EOPNOTSUPP;
315 	if (copy_from_user(&reg, arg, sizeof(reg)))
316 		return -EFAULT;
317 
318 	if (reg.flags & ~PR_FL_IGNORE_KEY)
319 		return -EOPNOTSUPP;
320 	return ops->pr_register(bdev, reg.old_key, reg.new_key, reg.flags);
321 }
322 
323 static int blkdev_pr_reserve(struct block_device *bdev,
324 		struct pr_reservation __user *arg)
325 {
326 	const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
327 	struct pr_reservation rsv;
328 
329 	if (!capable(CAP_SYS_ADMIN))
330 		return -EPERM;
331 	if (!ops || !ops->pr_reserve)
332 		return -EOPNOTSUPP;
333 	if (copy_from_user(&rsv, arg, sizeof(rsv)))
334 		return -EFAULT;
335 
336 	if (rsv.flags & ~PR_FL_IGNORE_KEY)
337 		return -EOPNOTSUPP;
338 	return ops->pr_reserve(bdev, rsv.key, rsv.type, rsv.flags);
339 }
340 
341 static int blkdev_pr_release(struct block_device *bdev,
342 		struct pr_reservation __user *arg)
343 {
344 	const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
345 	struct pr_reservation rsv;
346 
347 	if (!capable(CAP_SYS_ADMIN))
348 		return -EPERM;
349 	if (!ops || !ops->pr_release)
350 		return -EOPNOTSUPP;
351 	if (copy_from_user(&rsv, arg, sizeof(rsv)))
352 		return -EFAULT;
353 
354 	if (rsv.flags)
355 		return -EOPNOTSUPP;
356 	return ops->pr_release(bdev, rsv.key, rsv.type);
357 }
358 
359 static int blkdev_pr_preempt(struct block_device *bdev,
360 		struct pr_preempt __user *arg, bool abort)
361 {
362 	const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
363 	struct pr_preempt p;
364 
365 	if (!capable(CAP_SYS_ADMIN))
366 		return -EPERM;
367 	if (!ops || !ops->pr_preempt)
368 		return -EOPNOTSUPP;
369 	if (copy_from_user(&p, arg, sizeof(p)))
370 		return -EFAULT;
371 
372 	if (p.flags)
373 		return -EOPNOTSUPP;
374 	return ops->pr_preempt(bdev, p.old_key, p.new_key, p.type, abort);
375 }
376 
377 static int blkdev_pr_clear(struct block_device *bdev,
378 		struct pr_clear __user *arg)
379 {
380 	const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
381 	struct pr_clear c;
382 
383 	if (!capable(CAP_SYS_ADMIN))
384 		return -EPERM;
385 	if (!ops || !ops->pr_clear)
386 		return -EOPNOTSUPP;
387 	if (copy_from_user(&c, arg, sizeof(c)))
388 		return -EFAULT;
389 
390 	if (c.flags)
391 		return -EOPNOTSUPP;
392 	return ops->pr_clear(bdev, c.key);
393 }
394 
395 /*
396  * Is it an unrecognized ioctl? The correct returns are either
397  * ENOTTY (final) or ENOIOCTLCMD ("I don't know this one, try a
398  * fallback"). ENOIOCTLCMD gets turned into ENOTTY by the ioctl
399  * code before returning.
400  *
401  * Confused drivers sometimes return EINVAL, which is wrong. It
402  * means "I understood the ioctl command, but the parameters to
403  * it were wrong".
404  *
405  * We should aim to just fix the broken drivers, the EINVAL case
406  * should go away.
407  */
408 static inline int is_unrecognized_ioctl(int ret)
409 {
410 	return	ret == -EINVAL ||
411 		ret == -ENOTTY ||
412 		ret == -ENOIOCTLCMD;
413 }
414 
415 static int blkdev_flushbuf(struct block_device *bdev, fmode_t mode,
416 		unsigned cmd, unsigned long arg)
417 {
418 	int ret;
419 
420 	if (!capable(CAP_SYS_ADMIN))
421 		return -EACCES;
422 
423 	ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
424 	if (!is_unrecognized_ioctl(ret))
425 		return ret;
426 
427 	fsync_bdev(bdev);
428 	invalidate_bdev(bdev);
429 	return 0;
430 }
431 
432 static int blkdev_roset(struct block_device *bdev, fmode_t mode,
433 		unsigned cmd, unsigned long arg)
434 {
435 	int ret, n;
436 
437 	ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
438 	if (!is_unrecognized_ioctl(ret))
439 		return ret;
440 	if (!capable(CAP_SYS_ADMIN))
441 		return -EACCES;
442 	if (get_user(n, (int __user *)arg))
443 		return -EFAULT;
444 	set_device_ro(bdev, n);
445 	return 0;
446 }
447 
448 static int blkdev_getgeo(struct block_device *bdev,
449 		struct hd_geometry __user *argp)
450 {
451 	struct gendisk *disk = bdev->bd_disk;
452 	struct hd_geometry geo;
453 	int ret;
454 
455 	if (!argp)
456 		return -EINVAL;
457 	if (!disk->fops->getgeo)
458 		return -ENOTTY;
459 
460 	/*
461 	 * We need to set the startsect first, the driver may
462 	 * want to override it.
463 	 */
464 	memset(&geo, 0, sizeof(geo));
465 	geo.start = get_start_sect(bdev);
466 	ret = disk->fops->getgeo(bdev, &geo);
467 	if (ret)
468 		return ret;
469 	if (copy_to_user(argp, &geo, sizeof(geo)))
470 		return -EFAULT;
471 	return 0;
472 }
473 
474 /* set the logical block size */
475 static int blkdev_bszset(struct block_device *bdev, fmode_t mode,
476 		int __user *argp)
477 {
478 	int ret, n;
479 
480 	if (!capable(CAP_SYS_ADMIN))
481 		return -EACCES;
482 	if (!argp)
483 		return -EINVAL;
484 	if (get_user(n, argp))
485 		return -EFAULT;
486 
487 	if (!(mode & FMODE_EXCL)) {
488 		bdgrab(bdev);
489 		if (blkdev_get(bdev, mode | FMODE_EXCL, &bdev) < 0)
490 			return -EBUSY;
491 	}
492 
493 	ret = set_blocksize(bdev, n);
494 	if (!(mode & FMODE_EXCL))
495 		blkdev_put(bdev, mode | FMODE_EXCL);
496 	return ret;
497 }
498 
499 /*
500  * always keep this in sync with compat_blkdev_ioctl()
501  */
502 int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
503 			unsigned long arg)
504 {
505 	struct backing_dev_info *bdi;
506 	void __user *argp = (void __user *)arg;
507 	loff_t size;
508 	unsigned int max_sectors;
509 
510 	switch (cmd) {
511 	case BLKFLSBUF:
512 		return blkdev_flushbuf(bdev, mode, cmd, arg);
513 	case BLKROSET:
514 		return blkdev_roset(bdev, mode, cmd, arg);
515 	case BLKDISCARD:
516 		return blk_ioctl_discard(bdev, mode, arg, 0);
517 	case BLKSECDISCARD:
518 		return blk_ioctl_discard(bdev, mode, arg,
519 				BLKDEV_DISCARD_SECURE);
520 	case BLKZEROOUT:
521 		return blk_ioctl_zeroout(bdev, mode, arg);
522 	case HDIO_GETGEO:
523 		return blkdev_getgeo(bdev, argp);
524 	case BLKRAGET:
525 	case BLKFRAGET:
526 		if (!arg)
527 			return -EINVAL;
528 		bdi = blk_get_backing_dev_info(bdev);
529 		return put_long(arg, (bdi->ra_pages * PAGE_SIZE) / 512);
530 	case BLKROGET:
531 		return put_int(arg, bdev_read_only(bdev) != 0);
532 	case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
533 		return put_int(arg, block_size(bdev));
534 	case BLKSSZGET: /* get block device logical block size */
535 		return put_int(arg, bdev_logical_block_size(bdev));
536 	case BLKPBSZGET: /* get block device physical block size */
537 		return put_uint(arg, bdev_physical_block_size(bdev));
538 	case BLKIOMIN:
539 		return put_uint(arg, bdev_io_min(bdev));
540 	case BLKIOOPT:
541 		return put_uint(arg, bdev_io_opt(bdev));
542 	case BLKALIGNOFF:
543 		return put_int(arg, bdev_alignment_offset(bdev));
544 	case BLKDISCARDZEROES:
545 		return put_uint(arg, bdev_discard_zeroes_data(bdev));
546 	case BLKSECTGET:
547 		max_sectors = min_t(unsigned int, USHRT_MAX,
548 				    queue_max_sectors(bdev_get_queue(bdev)));
549 		return put_ushort(arg, max_sectors);
550 	case BLKROTATIONAL:
551 		return put_ushort(arg, !blk_queue_nonrot(bdev_get_queue(bdev)));
552 	case BLKRASET:
553 	case BLKFRASET:
554 		if(!capable(CAP_SYS_ADMIN))
555 			return -EACCES;
556 		bdi = blk_get_backing_dev_info(bdev);
557 		bdi->ra_pages = (arg * 512) / PAGE_SIZE;
558 		return 0;
559 	case BLKBSZSET:
560 		return blkdev_bszset(bdev, mode, argp);
561 	case BLKPG:
562 		return blkpg_ioctl(bdev, argp);
563 	case BLKRRPART:
564 		return blkdev_reread_part(bdev);
565 	case BLKGETSIZE:
566 		size = i_size_read(bdev->bd_inode);
567 		if ((size >> 9) > ~0UL)
568 			return -EFBIG;
569 		return put_ulong(arg, size >> 9);
570 	case BLKGETSIZE64:
571 		return put_u64(arg, i_size_read(bdev->bd_inode));
572 	case BLKTRACESTART:
573 	case BLKTRACESTOP:
574 	case BLKTRACESETUP:
575 	case BLKTRACETEARDOWN:
576 		return blk_trace_ioctl(bdev, cmd, argp);
577 	case IOC_PR_REGISTER:
578 		return blkdev_pr_register(bdev, argp);
579 	case IOC_PR_RESERVE:
580 		return blkdev_pr_reserve(bdev, argp);
581 	case IOC_PR_RELEASE:
582 		return blkdev_pr_release(bdev, argp);
583 	case IOC_PR_PREEMPT:
584 		return blkdev_pr_preempt(bdev, argp, false);
585 	case IOC_PR_PREEMPT_ABORT:
586 		return blkdev_pr_preempt(bdev, argp, true);
587 	case IOC_PR_CLEAR:
588 		return blkdev_pr_clear(bdev, argp);
589 	default:
590 		return __blkdev_driver_ioctl(bdev, mode, cmd, arg);
591 	}
592 }
593 EXPORT_SYMBOL_GPL(blkdev_ioctl);
594