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