tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
22/* Check validity of generic quotactl commands */
23static int generic_quotactl_valid(struct super_block *sb, int type, int cmd, qid_t id)
24{
25 if (type >= MAXQUOTAS)
26 return -EINVAL;
27 if (!sb && cmd != Q_SYNC)
28 return -ENODEV;
29 /* Is operation supported? */
30 if (sb && !sb->s_qcop)
31 return -ENOSYS;
32
33 switch (cmd) {
34 case Q_GETFMT:
35 break;
36 case Q_QUOTAON:
37 if (!sb->s_qcop->quota_on)
38 return -ENOSYS;
39 break;
40 case Q_QUOTAOFF:
41 if (!sb->s_qcop->quota_off)
42 return -ENOSYS;
43 break;
44 case Q_SETINFO:
45 if (!sb->s_qcop->set_info)
46 return -ENOSYS;
47 break;
48 case Q_GETINFO:
49 if (!sb->s_qcop->get_info)
50 return -ENOSYS;
51 break;
52 case Q_SETQUOTA:
53 if (!sb->s_qcop->set_dqblk)
54 return -ENOSYS;
55 break;
56 case Q_GETQUOTA:
57 if (!sb->s_qcop->get_dqblk)
58 return -ENOSYS;
59 break;
60 case Q_SYNC:
61 if (sb && !sb->s_qcop->quota_sync)
62 return -ENOSYS;
63 break;
64 default:
65 return -EINVAL;
66 }
67
68 /* Is quota turned on for commands which need it? */
69 switch (cmd) {
70 case Q_GETFMT:
71 case Q_GETINFO:
72 case Q_SETINFO:
73 case Q_SETQUOTA:
74 case Q_GETQUOTA:
75 /* This is just informative test so we are satisfied without a lock */
76 if (!sb_has_quota_enabled(sb, type))
77 return -ESRCH;
78 }
79
80 /* Check privileges */
81 if (cmd == Q_GETQUOTA) {
82 if (((type == USRQUOTA && current->euid != id) ||
83 (type == GRPQUOTA && !in_egroup_p(id))) &&
84 !capable(CAP_SYS_ADMIN))
85 return -EPERM;
86 }
87 else if (cmd != Q_GETFMT && cmd != Q_SYNC && cmd != Q_GETINFO)
88 if (!capable(CAP_SYS_ADMIN))
89 return -EPERM;
90
91 return 0;
92}
93
94/* Check validity of XFS Quota Manager commands */
95static int xqm_quotactl_valid(struct super_block *sb, int type, int cmd, qid_t id)
96{
97 if (type >= XQM_MAXQUOTAS)
98 return -EINVAL;
99 if (!sb)
100 return -ENODEV;
101 if (!sb->s_qcop)
102 return -ENOSYS;
103
104 switch (cmd) {
105 case Q_XQUOTAON:
106 case Q_XQUOTAOFF:
107 case Q_XQUOTARM:
108 if (!sb->s_qcop->set_xstate)
109 return -ENOSYS;
110 break;
111 case Q_XGETQSTAT:
112 if (!sb->s_qcop->get_xstate)
113 return -ENOSYS;
114 break;
115 case Q_XSETQLIM:
116 if (!sb->s_qcop->set_xquota)
117 return -ENOSYS;
118 break;
119 case Q_XGETQUOTA:
120 if (!sb->s_qcop->get_xquota)
121 return -ENOSYS;
122 break;
123 case Q_XQUOTASYNC:
124 if (!sb->s_qcop->quota_sync)
125 return -ENOSYS;
126 break;
127 default:
128 return -EINVAL;
129 }
130
131 /* Check privileges */
132 if (cmd == Q_XGETQUOTA) {
133 if (((type == XQM_USRQUOTA && current->euid != id) ||
134 (type == XQM_GRPQUOTA && !in_egroup_p(id))) &&
135 !capable(CAP_SYS_ADMIN))
136 return -EPERM;
137 } else if (cmd != Q_XGETQSTAT && cmd != Q_XQUOTASYNC) {
138 if (!capable(CAP_SYS_ADMIN))
139 return -EPERM;
140 }
141
142 return 0;
143}
144
145static int check_quotactl_valid(struct super_block *sb, int type, int cmd, qid_t id)
146{
147 int error;
148
149 if (XQM_COMMAND(cmd))
150 error = xqm_quotactl_valid(sb, type, cmd, id);
151 else
152 error = generic_quotactl_valid(sb, type, cmd, id);
153 if (!error)
154 error = security_quotactl(cmd, type, id, sb);
155 return error;
156}
157
158static void quota_sync_sb(struct super_block *sb, int type)
159{
160 int cnt;
161
162 sb->s_qcop->quota_sync(sb, type);
163 /* This is not very clever (and fast) but currently I don't know about
164 * any other simple way of getting quota data to disk and we must get
165 * them there for userspace to be visible... */
166 if (sb->s_op->sync_fs)
167 sb->s_op->sync_fs(sb, 1);
168 sync_blockdev(sb->s_bdev);
169
170 /*
171 * Now when everything is written we can discard the pagecache so
172 * that userspace sees the changes.
173 */
174 mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
175 for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
176 if (type != -1 && cnt != type)
177 continue;
178 if (!sb_has_quota_enabled(sb, cnt))
179 continue;
180 mutex_lock_nested(&sb_dqopt(sb)->files[cnt]->i_mutex, I_MUTEX_QUOTA);
181 truncate_inode_pages(&sb_dqopt(sb)->files[cnt]->i_data, 0);
182 mutex_unlock(&sb_dqopt(sb)->files[cnt]->i_mutex);
183 }
184 mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
185}
186
187void sync_dquots(struct super_block *sb, int type)
188{
189 int cnt;
190
191 if (sb) {
192 if (sb->s_qcop->quota_sync)
193 quota_sync_sb(sb, type);
194 return;
195 }
196
197 spin_lock(&sb_lock);
198restart:
199 list_for_each_entry(sb, &super_blocks, s_list) {
200 /* This test just improves performance so it needn't be reliable... */
201 for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
202 if (type != -1 && type != cnt)
203 continue;
204 if (!sb_has_quota_enabled(sb, cnt))
205 continue;
206 if (!info_dirty(&sb_dqopt(sb)->info[cnt]) &&
207 list_empty(&sb_dqopt(sb)->info[cnt].dqi_dirty_list))
208 continue;
209 break;
210 }
211 if (cnt == MAXQUOTAS)
212 continue;
213 sb->s_count++;
214 spin_unlock(&sb_lock);
215 down_read(&sb->s_umount);
216 if (sb->s_root && sb->s_qcop->quota_sync)
217 quota_sync_sb(sb, type);
218 up_read(&sb->s_umount);
219 spin_lock(&sb_lock);
220 if (__put_super_and_need_restart(sb))
221 goto restart;
222 }
223 spin_unlock(&sb_lock);
224}
225
226/* Copy parameters and call proper function */
227static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id, void __user *addr)
228{
229 int ret;
230
231 switch (cmd) {
232 case Q_QUOTAON: {
233 char *pathname;
234
235 if (IS_ERR(pathname = getname(addr)))
236 return PTR_ERR(pathname);
237 ret = sb->s_qcop->quota_on(sb, type, id, pathname, 0);
238 putname(pathname);
239 return ret;
240 }
241 case Q_QUOTAOFF:
242 return sb->s_qcop->quota_off(sb, type, 0);
243
244 case Q_GETFMT: {
245 __u32 fmt;
246
247 down_read(&sb_dqopt(sb)->dqptr_sem);
248 if (!sb_has_quota_enabled(sb, type)) {
249 up_read(&sb_dqopt(sb)->dqptr_sem);
250 return -ESRCH;
251 }
252 fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
253 up_read(&sb_dqopt(sb)->dqptr_sem);
254 if (copy_to_user(addr, &fmt, sizeof(fmt)))
255 return -EFAULT;
256 return 0;
257 }
258 case Q_GETINFO: {
259 struct if_dqinfo info;
260
261 if ((ret = sb->s_qcop->get_info(sb, type, &info)))
262 return ret;
263 if (copy_to_user(addr, &info, sizeof(info)))
264 return -EFAULT;
265 return 0;
266 }
267 case Q_SETINFO: {
268 struct if_dqinfo info;
269
270 if (copy_from_user(&info, addr, sizeof(info)))
271 return -EFAULT;
272 return sb->s_qcop->set_info(sb, type, &info);
273 }
274 case Q_GETQUOTA: {
275 struct if_dqblk idq;
276
277 if ((ret = sb->s_qcop->get_dqblk(sb, type, id, &idq)))
278 return ret;
279 if (copy_to_user(addr, &idq, sizeof(idq)))
280 return -EFAULT;
281 return 0;
282 }
283 case Q_SETQUOTA: {
284 struct if_dqblk idq;
285
286 if (copy_from_user(&idq, addr, sizeof(idq)))
287 return -EFAULT;
288 return sb->s_qcop->set_dqblk(sb, type, id, &idq);
289 }
290 case Q_SYNC:
291 sync_dquots(sb, type);
292 return 0;
293
294 case Q_XQUOTAON:
295 case Q_XQUOTAOFF:
296 case Q_XQUOTARM: {
297 __u32 flags;
298
299 if (copy_from_user(&flags, addr, sizeof(flags)))
300 return -EFAULT;
301 return sb->s_qcop->set_xstate(sb, flags, cmd);
302 }
303 case Q_XGETQSTAT: {
304 struct fs_quota_stat fqs;
305
306 if ((ret = sb->s_qcop->get_xstate(sb, &fqs)))
307 return ret;
308 if (copy_to_user(addr, &fqs, sizeof(fqs)))
309 return -EFAULT;
310 return 0;
311 }
312 case Q_XSETQLIM: {
313 struct fs_disk_quota fdq;
314
315 if (copy_from_user(&fdq, addr, sizeof(fdq)))
316 return -EFAULT;
317 return sb->s_qcop->set_xquota(sb, type, id, &fdq);
318 }
319 case Q_XGETQUOTA: {
320 struct fs_disk_quota fdq;
321
322 if ((ret = sb->s_qcop->get_xquota(sb, type, id, &fdq)))
323 return ret;
324 if (copy_to_user(addr, &fdq, sizeof(fdq)))
325 return -EFAULT;
326 return 0;
327 }
328 case Q_XQUOTASYNC:
329 return sb->s_qcop->quota_sync(sb, type);
330 /* We never reach here unless validity check is broken */
331 default:
332 BUG();
333 }
334 return 0;
335}
336
337/*
338 * look up a superblock on which quota ops will be performed
339 * - use the name of a block device to find the superblock thereon
340 */
341static inline struct super_block *quotactl_block(const char __user *special)
342{
343#ifdef CONFIG_BLOCK
344 struct block_device *bdev;
345 struct super_block *sb;
346 char *tmp = getname(special);
347
348 if (IS_ERR(tmp))
349 return ERR_CAST(tmp);
350 bdev = lookup_bdev(tmp);
351 putname(tmp);
352 if (IS_ERR(bdev))
353 return ERR_CAST(bdev);
354 sb = get_super(bdev);
355 bdput(bdev);
356 if (!sb)
357 return ERR_PTR(-ENODEV);
358
359 return sb;
360#else
361 return ERR_PTR(-ENODEV);
362#endif
363}
364
365/*
366 * This is the system call interface. This communicates with
367 * the user-level programs. Currently this only supports diskquota
368 * calls. Maybe we need to add the process quotas etc. in the future,
369 * but we probably should use rlimits for that.
370 */
371asmlinkage long sys_quotactl(unsigned int cmd, const char __user *special, qid_t id, void __user *addr)
372{
373 uint cmds, type;
374 struct super_block *sb = NULL;
375 int ret;
376
377 cmds = cmd >> SUBCMDSHIFT;
378 type = cmd & SUBCMDMASK;
379
380 if (cmds != Q_SYNC || special) {
381 sb = quotactl_block(special);
382 if (IS_ERR(sb))
383 return PTR_ERR(sb);
384 }
385
386 ret = check_quotactl_valid(sb, type, cmds, id);
387 if (ret >= 0)
388 ret = do_quotactl(sb, type, cmds, id, addr);
389 if (sb)
390 drop_super(sb);
391
392 return ret;
393}
394
395#if defined(CONFIG_COMPAT_FOR_U64_ALIGNMENT)
396/*
397 * This code works only for 32 bit quota tools over 64 bit OS (x86_64, ia64)
398 * and is necessary due to alignment problems.
399 */
400struct compat_if_dqblk {
401 compat_u64 dqb_bhardlimit;
402 compat_u64 dqb_bsoftlimit;
403 compat_u64 dqb_curspace;
404 compat_u64 dqb_ihardlimit;
405 compat_u64 dqb_isoftlimit;
406 compat_u64 dqb_curinodes;
407 compat_u64 dqb_btime;
408 compat_u64 dqb_itime;
409 compat_uint_t dqb_valid;
410};
411
412/* XFS structures */
413struct compat_fs_qfilestat {
414 compat_u64 dqb_bhardlimit;
415 compat_u64 qfs_nblks;
416 compat_uint_t qfs_nextents;
417};
418
419struct compat_fs_quota_stat {
420 __s8 qs_version;
421 __u16 qs_flags;
422 __s8 qs_pad;
423 struct compat_fs_qfilestat qs_uquota;
424 struct compat_fs_qfilestat qs_gquota;
425 compat_uint_t qs_incoredqs;
426 compat_int_t qs_btimelimit;
427 compat_int_t qs_itimelimit;
428 compat_int_t qs_rtbtimelimit;
429 __u16 qs_bwarnlimit;
430 __u16 qs_iwarnlimit;
431};
432
433asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
434 qid_t id, void __user *addr)
435{
436 unsigned int cmds;
437 struct if_dqblk __user *dqblk;
438 struct compat_if_dqblk __user *compat_dqblk;
439 struct fs_quota_stat __user *fsqstat;
440 struct compat_fs_quota_stat __user *compat_fsqstat;
441 compat_uint_t data;
442 u16 xdata;
443 long ret;
444
445 cmds = cmd >> SUBCMDSHIFT;
446
447 switch (cmds) {
448 case Q_GETQUOTA:
449 dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
450 compat_dqblk = addr;
451 ret = sys_quotactl(cmd, special, id, dqblk);
452 if (ret)
453 break;
454 if (copy_in_user(compat_dqblk, dqblk, sizeof(*compat_dqblk)) ||
455 get_user(data, &dqblk->dqb_valid) ||
456 put_user(data, &compat_dqblk->dqb_valid))
457 ret = -EFAULT;
458 break;
459 case Q_SETQUOTA:
460 dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
461 compat_dqblk = addr;
462 ret = -EFAULT;
463 if (copy_in_user(dqblk, compat_dqblk, sizeof(*compat_dqblk)) ||
464 get_user(data, &compat_dqblk->dqb_valid) ||
465 put_user(data, &dqblk->dqb_valid))
466 break;
467 ret = sys_quotactl(cmd, special, id, dqblk);
468 break;
469 case Q_XGETQSTAT:
470 fsqstat = compat_alloc_user_space(sizeof(struct fs_quota_stat));
471 compat_fsqstat = addr;
472 ret = sys_quotactl(cmd, special, id, fsqstat);
473 if (ret)
474 break;
475 ret = -EFAULT;
476 /* Copying qs_version, qs_flags, qs_pad */
477 if (copy_in_user(compat_fsqstat, fsqstat,
478 offsetof(struct compat_fs_quota_stat, qs_uquota)))
479 break;
480 /* Copying qs_uquota */
481 if (copy_in_user(&compat_fsqstat->qs_uquota,
482 &fsqstat->qs_uquota,
483 sizeof(compat_fsqstat->qs_uquota)) ||
484 get_user(data, &fsqstat->qs_uquota.qfs_nextents) ||
485 put_user(data, &compat_fsqstat->qs_uquota.qfs_nextents))
486 break;
487 /* Copying qs_gquota */
488 if (copy_in_user(&compat_fsqstat->qs_gquota,
489 &fsqstat->qs_gquota,
490 sizeof(compat_fsqstat->qs_gquota)) ||
491 get_user(data, &fsqstat->qs_gquota.qfs_nextents) ||
492 put_user(data, &compat_fsqstat->qs_gquota.qfs_nextents))
493 break;
494 /* Copying the rest */
495 if (copy_in_user(&compat_fsqstat->qs_incoredqs,
496 &fsqstat->qs_incoredqs,
497 sizeof(struct compat_fs_quota_stat) -
498 offsetof(struct compat_fs_quota_stat, qs_incoredqs)) ||
499 get_user(xdata, &fsqstat->qs_iwarnlimit) ||
500 put_user(xdata, &compat_fsqstat->qs_iwarnlimit))
501 break;
502 ret = 0;
503 break;
504 default:
505 ret = sys_quotactl(cmd, special, id, addr);
506 }
507 return ret;
508}
509#endif