aboutsummaryrefslogtreecommitdiffstats
path: root/fs/quota/quota.c
blob: d76ada914f9898f7b8c4c1435469110a35449561 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
/*
 * Quota code necessary even when VFS quota support is not compiled
 * into the kernel.  The interesting stuff is over in dquot.c, here
 * we have symbols for initial quotactl(2) handling, the sysctl(2)
 * variables, etc - things needed even when quota support disabled.
 */

#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/slab.h>
#include <asm/current.h>
#include <asm/uaccess.h>
#include <linux/compat.h>
#include <linux/kernel.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/buffer_head.h>
#include <linux/capability.h>
#include <linux/quotaops.h>
#include <linux/types.h>

/* Check validity of generic quotactl commands */
static int generic_quotactl_valid(struct super_block *sb, int type, int cmd, qid_t id)
{
	if (type >= MAXQUOTAS)
		return -EINVAL;
	if (!sb && cmd != Q_SYNC)
		return -ENODEV;
	/* Is operation supported? */
	if (sb && !sb->s_qcop)
		return -ENOSYS;

	switch (cmd) {
		case Q_GETFMT:
			break;
		case Q_QUOTAON:
			if (!sb->s_qcop->quota_on)
				return -ENOSYS;
			break;
		case Q_QUOTAOFF:
			if (!sb->s_qcop->quota_off)
				return -ENOSYS;
			break;
		case Q_SETINFO:
			if (!sb->s_qcop->set_info)
				return -ENOSYS;
			break;
		case Q_GETINFO:
			if (!sb->s_qcop->get_info)
				return -ENOSYS;
			break;
		case Q_SETQUOTA:
			if (!sb->s_qcop->set_dqblk)
				return -ENOSYS;
			break;
		case Q_GETQUOTA:
			if (!sb->s_qcop->get_dqblk)
				return -ENOSYS;
			break;
		case Q_SYNC:
			if (sb && !sb->s_qcop->quota_sync)
				return -ENOSYS;
			break;
		default:
			return -EINVAL;
	}

	/* Is quota turned on for commands which need it? */
	switch (cmd) {
		case Q_GETFMT:
		case Q_GETINFO:
		case Q_SETINFO:
		case Q_SETQUOTA:
		case Q_GETQUOTA:
			/* This is just informative test so we are satisfied without a lock */
			if (!sb_has_quota_active(sb, type))
				return -ESRCH;
	}

	/* Check privileges */
	if (cmd == Q_GETQUOTA) {
		if (((type == USRQUOTA && current_euid() != id) ||
		     (type == GRPQUOTA && !in_egroup_p(id))) &&
		    !capable(CAP_SYS_ADMIN))
			return -EPERM;
	}
	else if (cmd != Q_GETFMT && cmd != Q_SYNC && cmd != Q_GETINFO)
		if (!capable(CAP_SYS_ADMIN))
			return -EPERM;

	return 0;
}

/* Check validity of XFS Quota Manager commands */
static int xqm_quotactl_valid(struct super_block *sb, int type, int cmd, qid_t id)
{
	if (type >= XQM_MAXQUOTAS)
		return -EINVAL;
	if (!sb)
		return -ENODEV;
	if (!sb->s_qcop)
		return -ENOSYS;

	switch (cmd) {
		case Q_XQUOTAON:
		case Q_XQUOTAOFF:
		case Q_XQUOTARM:
			if (!sb->s_qcop->set_xstate)
				return -ENOSYS;
			break;
		case Q_XGETQSTAT:
			if (!sb->s_qcop->get_xstate)
				return -ENOSYS;
			break;
		case Q_XSETQLIM:
			if (!sb->s_qcop->set_xquota)
				return -ENOSYS;
			break;
		case Q_XGETQUOTA:
			if (!sb->s_qcop->get_xquota)
				return -ENOSYS;
			break;
		case Q_XQUOTASYNC:
			if (!sb->s_qcop->quota_sync)
				return -ENOSYS;
			break;
		default:
			return -EINVAL;
	}

	/* Check privileges */
	if (cmd == Q_XGETQUOTA) {
		if (((type == XQM_USRQUOTA && current_euid() != id) ||
		     (type == XQM_GRPQUOTA && !in_egroup_p(id))) &&
		     !capable(CAP_SYS_ADMIN))
			return -EPERM;
	} else if (cmd != Q_XGETQSTAT && cmd != Q_XQUOTASYNC) {
		if (!capable(CAP_SYS_ADMIN))
			return -EPERM;
	}

	return 0;
}

static int check_quotactl_valid(struct super_block *sb, int type, int cmd, qid_t id)
{
	int error;

	if (XQM_COMMAND(cmd))
		error = xqm_quotactl_valid(sb, type, cmd, id);
	else
		error = generic_quotactl_valid(sb, type, cmd, id);
	if (!error)
		error = security_quotactl(cmd, type, id, sb);
	return error;
}

static void quota_sync_sb(struct super_block *sb, int type)
{
	int cnt;

	sb->s_qcop->quota_sync(sb, type);

	if (sb_dqopt(sb)->flags & DQUOT_QUOTA_SYS_FILE)
		return;
	/* This is not very clever (and fast) but currently I don't know about
	 * any other simple way of getting quota data to disk and we must get
	 * them there for userspace to be visible... */
	if (sb->s_op->sync_fs)
		sb->s_op->sync_fs(sb, 1);
	sync_blockdev(sb->s_bdev);

	/*
	 * Now when everything is written we can discard the pagecache so
	 * that userspace sees the changes.
	 */
	mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		if (type != -1 && cnt != type)
			continue;
		if (!sb_has_quota_active(sb, cnt))
			continue;
		mutex_lock_nested(&sb_dqopt(sb)->files[cnt]->i_mutex, I_MUTEX_QUOTA);
		truncate_inode_pages(&sb_dqopt(sb)->files[cnt]->i_data, 0);
		mutex_unlock(&sb_dqopt(sb)->files[cnt]->i_mutex);
	}
	mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
}

void sync_dquots(struct super_block *sb, int type)
{
	int cnt;

	if (sb) {
		if (sb->s_qcop->quota_sync)
			quota_sync_sb(sb, type);
		return;
	}

	spin_lock(&sb_lock);
restart:
	list_for_each_entry(sb, &super_blocks, s_list) {
		/* This test just improves performance so it needn't be reliable... */
		for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
			if (type != -1 && type != cnt)
				continue;
			if (!sb_has_quota_active(sb, cnt))
				continue;
			if (!info_dirty(&sb_dqopt(sb)->info[cnt]) &&
			    list_empty(&sb_dqopt(sb)->info[cnt].dqi_dirty_list))
				continue;
			break;
		}
		if (cnt == MAXQUOTAS)
			continue;
		sb->s_count++;
		spin_unlock(&sb_lock);
		down_read(&sb->s_umount);
		if (sb->s_root && sb->s_qcop->quota_sync)
			quota_sync_sb(sb, type);
		up_read(&sb->s_umount);
		spin_lock(&sb_lock);
		if (__put_super_and_need_restart(sb))
			goto restart;
	}
	spin_unlock(&sb_lock);
}

/* Copy parameters and call proper function */
static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id, void __user *addr)
{
	int ret;

	switch (cmd) {
		case Q_QUOTAON: {
			char *pathname;

			if (IS_ERR(pathname = getname(addr)))
				return PTR_ERR(pathname);
			ret = sb->s_qcop->quota_on(sb, type, id, pathname, 0);
			putname(pathname);
			return ret;
		}
		case Q_QUOTAOFF:
			return sb->s_qcop->quota_off(sb, type, 0);

		case Q_GETFMT: {
			__u32 fmt;

			down_read(&sb_dqopt(sb)->dqptr_sem);
			if (!sb_has_quota_active(sb, type)) {
				up_read(&sb_dqopt(sb)->dqptr_sem);
				return -ESRCH;
			}
			fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
			up_read(&sb_dqopt(sb)->dqptr_sem);
			if (copy_to_user(addr, &fmt, sizeof(fmt)))
				return -EFAULT;
			return 0;
		}
		case Q_GETINFO: {
			struct if_dqinfo info;

			if ((ret = sb->s_qcop->get_info(sb, type, &info)))
				return ret;
			if (copy_to_user(addr, &info, sizeof(info)))
				return -EFAULT;
			return 0;
		}
		case Q_SETINFO: {
			struct if_dqinfo info;

			if (copy_from_user(&info, addr, sizeof(info)))
				return -EFAULT;
			return sb->s_qcop->set_info(sb, type, &info);
		}
		case Q_GETQUOTA: {
			struct if_dqblk idq;

			if ((ret = sb->s_qcop->get_dqblk(sb, type, id, &idq)))
				return ret;
			if (copy_to_user(addr, &idq, sizeof(idq)))
				return -EFAULT;
			return 0;
		}
		case Q_SETQUOTA: {
			struct if_dqblk idq;

			if (copy_from_user(&idq, addr, sizeof(idq)))
				return -EFAULT;
			return sb->s_qcop->set_dqblk(sb, type, id, &idq);
		}
		case Q_SYNC:
			sync_dquots(sb, type);
			return 0;

		case Q_XQUOTAON:
		case Q_XQUOTAOFF:
		case Q_XQUOTARM: {
			__u32 flags;

			if (copy_from_user(&flags, addr, sizeof(flags)))
				return -EFAULT;
			return sb->s_qcop->set_xstate(sb, flags, cmd);
		}
		case Q_XGETQSTAT: {
			struct fs_quota_stat fqs;
		
			if ((ret = sb->s_qcop->get_xstate(sb, &fqs)))
				return ret;
			if (copy_to_user(addr, &fqs, sizeof(fqs)))
				return -EFAULT;
			return 0;
		}
		case Q_XSETQLIM: {
			struct fs_disk_quota fdq;

			if (copy_from_user(&fdq, addr, sizeof(fdq)))
				return -EFAULT;
		       return sb->s_qcop->set_xquota(sb, type, id, &fdq);
		}
		case Q_XGETQUOTA: {
			struct fs_disk_quota fdq;

			if ((ret = sb->s_qcop->get_xquota(sb, type, id, &fdq)))
				return ret;
			if (copy_to_user(addr, &fdq, sizeof(fdq)))
				return -EFAULT;
			return 0;
		}
		case Q_XQUOTASYNC:
			return sb->s_qcop->quota_sync(sb, type);
		/* We never reach here unless validity check is broken */
		default:
			BUG();
	}
	return 0;
}

/*
 * look up a superblock on which quota ops will be performed
 * - use the name of a block device to find the superblock thereon
 */
static inline struct super_block *quotactl_block(const char __user *special)
{
#ifdef CONFIG_BLOCK
	struct block_device *bdev;
	struct super_block *sb;
	char *tmp = getname(special);

	if (IS_ERR(tmp))
		return ERR_CAST(tmp);
	bdev = lookup_bdev(tmp);
	putname(tmp);
	if (IS_ERR(bdev))
		return ERR_CAST(bdev);
	sb = get_super(bdev);
	bdput(bdev);
	if (!sb)
		return ERR_PTR(-ENODEV);

	return sb;
#else
	return ERR_PTR(-ENODEV);
#endif
}

/*
 * This is the system call interface. This communicates with
 * the user-level programs. Currently this only supports diskquota
 * calls. Maybe we need to add the process quotas etc. in the future,
 * but we probably should use rlimits for that.
 */
SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
		qid_t, id, void __user *, addr)
{
	uint cmds, type;
	struct super_block *sb = NULL;
	int ret;

	cmds = cmd >> SUBCMDSHIFT;
	type = cmd & SUBCMDMASK;

	if (cmds != Q_SYNC || special) {
		sb = quotactl_block(special);
		if (IS_ERR(sb))
			return PTR_ERR(sb);
	}

	ret = check_quotactl_valid(sb, type, cmds, id);
	if (ret >= 0)
		ret = do_quotactl(sb, type, cmds, id, addr);
	if (sb)
		drop_super(sb);

	return ret;
}

#if defined(CONFIG_COMPAT_FOR_U64_ALIGNMENT)
/*
 * This code works only for 32 bit quota tools over 64 bit OS (x86_64, ia64)
 * and is necessary due to alignment problems.
 */
struct compat_if_dqblk {
	compat_u64 dqb_bhardlimit;
	compat_u64 dqb_bsoftlimit;
	compat_u64 dqb_curspace;
	compat_u64 dqb_ihardlimit;
	compat_u64 dqb_isoftlimit;
	compat_u64 dqb_curinodes;
	compat_u64 dqb_btime;
	compat_u64 dqb_itime;
	compat_uint_t dqb_valid;
};

/* XFS structures */
struct compat_fs_qfilestat {
	compat_u64 dqb_bhardlimit;
	compat_u64 qfs_nblks;
	compat_uint_t qfs_nextents;
};

struct compat_fs_quota_stat {
	__s8		qs_version;
	__u16		qs_flags;
	__s8		qs_pad;
	struct compat_fs_qfilestat	qs_uquota;
	struct compat_fs_qfilestat	qs_gquota;
	compat_uint_t	qs_incoredqs;
	compat_int_t	qs_btimelimit;
	compat_int_t	qs_itimelimit;
	compat_int_t	qs_rtbtimelimit;
	__u16		qs_bwarnlimit;
	__u16		qs_iwarnlimit;
};

asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
						qid_t id, void __user *addr)
{
	unsigned int cmds;
	struct if_dqblk __user *dqblk;
	struct compat_if_dqblk __user *compat_dqblk;
	struct fs_quota_stat __user *fsqstat;
	struct compat_fs_quota_stat __user *compat_fsqstat;
	compat_uint_t data;
	u16 xdata;
	long ret;

	cmds = cmd >> SUBCMDSHIFT;

	switch (cmds) {
	case Q_GETQUOTA:
		dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
		compat_dqblk = addr;
		ret = sys_quotactl(cmd, special, id, dqblk);
		if (ret)
			break;
		if (copy_in_user(compat_dqblk, dqblk, sizeof(*compat_dqblk)) ||
			get_user(data, &dqblk->dqb_valid) ||
			put_user(data, &compat_dqblk->dqb_valid))
			ret = -EFAULT;
		break;
	case Q_SETQUOTA:
		dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
		compat_dqblk = addr;
		ret = -EFAULT;
		if (copy_in_user(dqblk, compat_dqblk, sizeof(*compat_dqblk)) ||
			get_user(data, &compat_dqblk->dqb_valid) ||
			put_user(data, &dqblk->dqb_valid))
			break;
		ret = sys_quotactl(cmd, special, id, dqblk);
		break;
	case Q_XGETQSTAT:
		fsqstat = compat_alloc_user_space(sizeof(struct fs_quota_stat));
		compat_fsqstat = addr;
		ret = sys_quotactl(cmd, special, id, fsqstat);
		if (ret)
			break;
		ret = -EFAULT;
		/* Copying qs_version, qs_flags, qs_pad */
		if (copy_in_user(compat_fsqstat, fsqstat,
			offsetof(struct compat_fs_quota_stat, qs_uquota)))
			break;
		/* Copying qs_uquota */
		if (copy_in_user(&compat_fsqstat->qs_uquota,
			&fsqstat->qs_uquota,
			sizeof(compat_fsqstat->qs_uquota)) ||
			get_user(data, &fsqstat->qs_uquota.qfs_nextents) ||
			put_user(data, &compat_fsqstat->qs_uquota.qfs_nextents))
			break;
		/* Copying qs_gquota */
		if (copy_in_user(&compat_fsqstat->qs_gquota,
			&fsqstat->qs_gquota,
			sizeof(compat_fsqstat->qs_gquota)) ||
			get_user(data, &fsqstat->qs_gquota.qfs_nextents) ||
			put_user(data, &compat_fsqstat->qs_gquota.qfs_nextents))
			break;
		/* Copying the rest */
		if (copy_in_user(&compat_fsqstat->qs_incoredqs,
			&fsqstat->qs_incoredqs,
			sizeof(struct compat_fs_quota_stat) -
			offsetof(struct compat_fs_quota_stat, qs_incoredqs)) ||
			get_user(xdata, &fsqstat->qs_iwarnlimit) ||
			put_user(xdata, &compat_fsqstat->qs_iwarnlimit))
			break;
		ret = 0;
		break;
	default:
		ret = sys_quotactl(cmd, special, id, addr);
	}
	return ret;
}
#endif