]>
Commit | Line | Data |
---|---|---|
b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
33d3dfff | 2 | #include <linux/fanotify.h> |
ff0b16a9 EP |
3 | #include <linux/fdtable.h> |
4 | #include <linux/fsnotify_backend.h> | |
5 | #include <linux/init.h> | |
9e66e423 | 6 | #include <linux/jiffies.h> |
ff0b16a9 | 7 | #include <linux/kernel.h> /* UINT_MAX */ |
1c529063 | 8 | #include <linux/mount.h> |
9e66e423 | 9 | #include <linux/sched.h> |
5b825c3a | 10 | #include <linux/sched/user.h> |
7a36094d | 11 | #include <linux/sched/signal.h> |
ff0b16a9 | 12 | #include <linux/types.h> |
9e66e423 | 13 | #include <linux/wait.h> |
de8cd83e | 14 | #include <linux/audit.h> |
d46eb14b | 15 | #include <linux/sched/mm.h> |
e9e0c890 | 16 | #include <linux/statfs.h> |
ff0b16a9 | 17 | |
7053aee2 JK |
18 | #include "fanotify.h" |
19 | ||
afc894c7 JK |
20 | static bool fanotify_path_equal(struct path *p1, struct path *p2) |
21 | { | |
22 | return p1->mnt == p2->mnt && p1->dentry == p2->dentry; | |
23 | } | |
24 | ||
25 | static inline bool fanotify_fsid_equal(__kernel_fsid_t *fsid1, | |
26 | __kernel_fsid_t *fsid2) | |
27 | { | |
6def1a1d | 28 | return fsid1->val[0] == fsid2->val[0] && fsid1->val[1] == fsid2->val[1]; |
afc894c7 JK |
29 | } |
30 | ||
31 | static bool fanotify_fh_equal(struct fanotify_fh *fh1, | |
7088f357 | 32 | struct fanotify_fh *fh2) |
afc894c7 JK |
33 | { |
34 | if (fh1->type != fh2->type || fh1->len != fh2->len) | |
35 | return false; | |
36 | ||
37 | /* Do not merge events if we failed to encode fh */ | |
38 | if (fh1->type == FILEID_INVALID) | |
39 | return false; | |
40 | ||
41 | return !fh1->len || | |
42 | !memcmp(fanotify_fh_buf(fh1), fanotify_fh_buf(fh2), fh1->len); | |
43 | } | |
44 | ||
7088f357 JK |
45 | static bool fanotify_fid_event_equal(struct fanotify_fid_event *ffe1, |
46 | struct fanotify_fid_event *ffe2) | |
47 | { | |
48 | /* Do not merge fid events without object fh */ | |
49 | if (!ffe1->object_fh.len) | |
50 | return false; | |
51 | ||
52 | return fanotify_fsid_equal(&ffe1->fsid, &ffe2->fsid) && | |
53 | fanotify_fh_equal(&ffe1->object_fh, &ffe2->object_fh); | |
54 | } | |
55 | ||
cacfb956 AG |
56 | static bool fanotify_name_event_equal(struct fanotify_name_event *fne1, |
57 | struct fanotify_name_event *fne2) | |
58 | { | |
59 | /* | |
60 | * Do not merge name events without dir fh. | |
61 | * FAN_DIR_MODIFY does not encode object fh, so it may be empty. | |
62 | */ | |
63 | if (!fne1->dir_fh.len) | |
64 | return false; | |
65 | ||
66 | if (fne1->name_len != fne2->name_len || | |
67 | !fanotify_fh_equal(&fne1->dir_fh, &fne2->dir_fh)) | |
68 | return false; | |
69 | ||
70 | return !memcmp(fne1->name, fne2->name, fne1->name_len); | |
71 | } | |
72 | ||
7053aee2 JK |
73 | static bool should_merge(struct fsnotify_event *old_fsn, |
74 | struct fsnotify_event *new_fsn) | |
767cd46c | 75 | { |
33913997 | 76 | struct fanotify_event *old, *new; |
767cd46c | 77 | |
7053aee2 JK |
78 | pr_debug("%s: old=%p new=%p\n", __func__, old_fsn, new_fsn); |
79 | old = FANOTIFY_E(old_fsn); | |
80 | new = FANOTIFY_E(new_fsn); | |
81 | ||
7088f357 JK |
82 | if (old_fsn->objectid != new_fsn->objectid || |
83 | old->type != new->type || old->pid != new->pid) | |
e9e0c890 AG |
84 | return false; |
85 | ||
7088f357 JK |
86 | switch (old->type) { |
87 | case FANOTIFY_EVENT_TYPE_PATH: | |
afc894c7 JK |
88 | return fanotify_path_equal(fanotify_event_path(old), |
89 | fanotify_event_path(new)); | |
7088f357 | 90 | case FANOTIFY_EVENT_TYPE_FID: |
e7fce6d9 AG |
91 | /* |
92 | * We want to merge many dirent events in the same dir (i.e. | |
93 | * creates/unlinks/renames), but we do not want to merge dirent | |
94 | * events referring to subdirs with dirent events referring to | |
95 | * non subdirs, otherwise, user won't be able to tell from a | |
96 | * mask FAN_CREATE|FAN_DELETE|FAN_ONDIR if it describes mkdir+ | |
97 | * unlink pair or rmdir+create pair of events. | |
98 | */ | |
afc894c7 JK |
99 | if ((old->mask & FS_ISDIR) != (new->mask & FS_ISDIR)) |
100 | return false; | |
101 | ||
7088f357 JK |
102 | return fanotify_fid_event_equal(FANOTIFY_FE(old), |
103 | FANOTIFY_FE(new)); | |
cacfb956 AG |
104 | case FANOTIFY_EVENT_TYPE_FID_NAME: |
105 | return fanotify_name_event_equal(FANOTIFY_NE(old), | |
106 | FANOTIFY_NE(new)); | |
7088f357 JK |
107 | default: |
108 | WARN_ON_ONCE(1); | |
e9e0c890 AG |
109 | } |
110 | ||
767cd46c EP |
111 | return false; |
112 | } | |
113 | ||
f70ab54c | 114 | /* and the list better be locked by something too! */ |
83c0e1b4 | 115 | static int fanotify_merge(struct list_head *list, struct fsnotify_event *event) |
767cd46c | 116 | { |
7053aee2 | 117 | struct fsnotify_event *test_event; |
33913997 | 118 | struct fanotify_event *new; |
767cd46c EP |
119 | |
120 | pr_debug("%s: list=%p event=%p\n", __func__, list, event); | |
a0a92d26 | 121 | new = FANOTIFY_E(event); |
767cd46c | 122 | |
13116dfd JK |
123 | /* |
124 | * Don't merge a permission event with any other event so that we know | |
125 | * the event structure we have created in fanotify_handle_event() is the | |
126 | * one we should check for permission response. | |
127 | */ | |
a0a92d26 | 128 | if (fanotify_is_perm_event(new->mask)) |
83c0e1b4 | 129 | return 0; |
13116dfd | 130 | |
7053aee2 JK |
131 | list_for_each_entry_reverse(test_event, list, list) { |
132 | if (should_merge(test_event, event)) { | |
a0a92d26 | 133 | FANOTIFY_E(test_event)->mask |= new->mask; |
6c71100d | 134 | return 1; |
a12a7dd3 EP |
135 | } |
136 | } | |
f70ab54c | 137 | |
6c71100d | 138 | return 0; |
767cd46c EP |
139 | } |
140 | ||
fabf7f29 JK |
141 | /* |
142 | * Wait for response to permission event. The function also takes care of | |
143 | * freeing the permission event (or offloads that in case the wait is canceled | |
144 | * by a signal). The function returns 0 in case access got allowed by userspace, | |
145 | * -EPERM in case userspace disallowed the access, and -ERESTARTSYS in case | |
146 | * the wait got interrupted by a signal. | |
147 | */ | |
f083441b | 148 | static int fanotify_get_response(struct fsnotify_group *group, |
33913997 | 149 | struct fanotify_perm_event *event, |
05f0e387 | 150 | struct fsnotify_iter_info *iter_info) |
9e66e423 EP |
151 | { |
152 | int ret; | |
153 | ||
154 | pr_debug("%s: group=%p event=%p\n", __func__, group, event); | |
155 | ||
b5190579 JK |
156 | ret = wait_event_killable(group->fanotify_data.access_waitq, |
157 | event->state == FAN_EVENT_ANSWERED); | |
fabf7f29 JK |
158 | /* Signal pending? */ |
159 | if (ret < 0) { | |
160 | spin_lock(&group->notification_lock); | |
161 | /* Event reported to userspace and no answer yet? */ | |
162 | if (event->state == FAN_EVENT_REPORTED) { | |
163 | /* Event will get freed once userspace answers to it */ | |
164 | event->state = FAN_EVENT_CANCELED; | |
165 | spin_unlock(&group->notification_lock); | |
166 | return ret; | |
167 | } | |
168 | /* Event not yet reported? Just remove it. */ | |
169 | if (event->state == FAN_EVENT_INIT) | |
170 | fsnotify_remove_queued_event(group, &event->fae.fse); | |
171 | /* | |
172 | * Event may be also answered in case signal delivery raced | |
173 | * with wakeup. In that case we have nothing to do besides | |
174 | * freeing the event and reporting error. | |
175 | */ | |
176 | spin_unlock(&group->notification_lock); | |
177 | goto out; | |
178 | } | |
9e66e423 EP |
179 | |
180 | /* userspace responded, convert to something usable */ | |
de8cd83e | 181 | switch (event->response & ~FAN_AUDIT) { |
9e66e423 EP |
182 | case FAN_ALLOW: |
183 | ret = 0; | |
184 | break; | |
185 | case FAN_DENY: | |
186 | default: | |
187 | ret = -EPERM; | |
188 | } | |
de8cd83e SG |
189 | |
190 | /* Check if the response should be audited */ | |
191 | if (event->response & FAN_AUDIT) | |
192 | audit_fanotify(event->response & ~FAN_AUDIT); | |
193 | ||
b2d87909 EP |
194 | pr_debug("%s: group=%p event=%p about to return ret=%d\n", __func__, |
195 | group, event, ret); | |
fabf7f29 JK |
196 | out: |
197 | fsnotify_destroy_event(group, &event->fae.fse); | |
83b535d2 | 198 | |
9e66e423 EP |
199 | return ret; |
200 | } | |
9e66e423 | 201 | |
2d10b230 MB |
202 | /* |
203 | * This function returns a mask for an event that only contains the flags | |
204 | * that have been specifically requested by the user. Flags that may have | |
205 | * been included within the event mask, but have not been explicitly | |
206 | * requested by the user, will not be present in the returned mask. | |
207 | */ | |
83b535d2 AG |
208 | static u32 fanotify_group_event_mask(struct fsnotify_group *group, |
209 | struct fsnotify_iter_info *iter_info, | |
210 | u32 event_mask, const void *data, | |
211 | int data_type) | |
1c529063 | 212 | { |
54a307ba | 213 | __u32 marks_mask = 0, marks_ignored_mask = 0; |
e7fce6d9 | 214 | __u32 test_mask, user_mask = FANOTIFY_OUTGOING_EVENTS; |
aa93bdc5 | 215 | const struct path *path = fsnotify_data_path(data, data_type); |
837a3934 AG |
216 | struct fsnotify_mark *mark; |
217 | int type; | |
1968f5ee | 218 | |
837a3934 AG |
219 | pr_debug("%s: report_mask=%x mask=%x data=%p data_type=%d\n", |
220 | __func__, iter_info->report_mask, event_mask, data, data_type); | |
1968f5ee | 221 | |
83b535d2 AG |
222 | if (!FAN_GROUP_FLAG(group, FAN_REPORT_FID)) { |
223 | /* Do we have path to open a file descriptor? */ | |
aa93bdc5 | 224 | if (!path) |
83b535d2 AG |
225 | return 0; |
226 | /* Path type events are only relevant for files and dirs */ | |
227 | if (!d_is_reg(path->dentry) && !d_can_lookup(path->dentry)) | |
228 | return 0; | |
229 | } | |
e1c048ba | 230 | |
837a3934 AG |
231 | fsnotify_foreach_obj_type(type) { |
232 | if (!fsnotify_iter_should_report_type(iter_info, type)) | |
233 | continue; | |
234 | mark = iter_info->marks[type]; | |
55bf882c AG |
235 | /* |
236 | * If the event is on dir and this mark doesn't care about | |
237 | * events on dir, don't send it! | |
238 | */ | |
239 | if (event_mask & FS_ISDIR && !(mark->mask & FS_ISDIR)) | |
240 | continue; | |
241 | ||
837a3934 | 242 | /* |
b469e7e4 AG |
243 | * If the event is for a child and this mark doesn't care about |
244 | * events on a child, don't send it! | |
837a3934 | 245 | */ |
b469e7e4 AG |
246 | if (event_mask & FS_EVENT_ON_CHILD && |
247 | (type != FSNOTIFY_OBJ_TYPE_INODE || | |
248 | !(mark->mask & FS_EVENT_ON_CHILD))) | |
837a3934 AG |
249 | continue; |
250 | ||
251 | marks_mask |= mark->mask; | |
252 | marks_ignored_mask |= mark->ignored_mask; | |
1968f5ee EP |
253 | } |
254 | ||
e7fce6d9 AG |
255 | test_mask = event_mask & marks_mask & ~marks_ignored_mask; |
256 | ||
257 | /* | |
9e2ba2c3 AG |
258 | * For dirent modification events (create/delete/move) that do not carry |
259 | * the child entry name information, we report FAN_ONDIR for mkdir/rmdir | |
260 | * so user can differentiate them from creat/unlink. | |
e7fce6d9 AG |
261 | * |
262 | * For backward compatibility and consistency, do not report FAN_ONDIR | |
263 | * to user in legacy fanotify mode (reporting fd) and report FAN_ONDIR | |
264 | * to user in FAN_REPORT_FID mode for all event types. | |
265 | */ | |
266 | if (FAN_GROUP_FLAG(group, FAN_REPORT_FID)) { | |
267 | /* Do not report FAN_ONDIR without any event */ | |
268 | if (!(test_mask & ~FAN_ONDIR)) | |
269 | return 0; | |
270 | } else { | |
271 | user_mask &= ~FAN_ONDIR; | |
272 | } | |
273 | ||
e7fce6d9 | 274 | return test_mask & user_mask; |
1c529063 EP |
275 | } |
276 | ||
afc894c7 JK |
277 | static void fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode, |
278 | gfp_t gfp) | |
e9e0c890 | 279 | { |
afc894c7 JK |
280 | int dwords, type, bytes = 0; |
281 | char *ext_buf = NULL; | |
282 | void *buf = fh->buf; | |
283 | int err; | |
e9e0c890 | 284 | |
cacfb956 AG |
285 | if (!inode) |
286 | goto out; | |
287 | ||
e9e0c890 AG |
288 | dwords = 0; |
289 | err = -ENOENT; | |
77115225 | 290 | type = exportfs_encode_inode_fh(inode, NULL, &dwords, NULL); |
e9e0c890 AG |
291 | if (!dwords) |
292 | goto out_err; | |
293 | ||
e9e0c890 AG |
294 | bytes = dwords << 2; |
295 | if (bytes > FANOTIFY_INLINE_FH_LEN) { | |
296 | /* Treat failure to allocate fh as failure to allocate event */ | |
297 | err = -ENOMEM; | |
afc894c7 JK |
298 | ext_buf = kmalloc(bytes, gfp); |
299 | if (!ext_buf) | |
e9e0c890 | 300 | goto out_err; |
afc894c7 JK |
301 | |
302 | *fanotify_fh_ext_buf_ptr(fh) = ext_buf; | |
303 | buf = ext_buf; | |
e9e0c890 AG |
304 | } |
305 | ||
afc894c7 | 306 | type = exportfs_encode_inode_fh(inode, buf, &dwords, NULL); |
e9e0c890 AG |
307 | err = -EINVAL; |
308 | if (!type || type == FILEID_INVALID || bytes != dwords << 2) | |
309 | goto out_err; | |
310 | ||
afc894c7 JK |
311 | fh->type = type; |
312 | fh->len = bytes; | |
e9e0c890 | 313 | |
afc894c7 | 314 | return; |
e9e0c890 AG |
315 | |
316 | out_err: | |
afc894c7 JK |
317 | pr_warn_ratelimited("fanotify: failed to encode fid (type=%d, len=%d, err=%i)\n", |
318 | type, bytes, err); | |
319 | kfree(ext_buf); | |
320 | *fanotify_fh_ext_buf_ptr(fh) = NULL; | |
cacfb956 | 321 | out: |
afc894c7 JK |
322 | /* Report the event without a file identifier on encode error */ |
323 | fh->type = FILEID_INVALID; | |
324 | fh->len = 0; | |
e9e0c890 AG |
325 | } |
326 | ||
83b535d2 AG |
327 | /* |
328 | * The inode to use as identifier when reporting fid depends on the event. | |
329 | * Report the modified directory inode on dirent modification events. | |
330 | * Report the "victim" inode otherwise. | |
331 | * For example: | |
332 | * FS_ATTRIB reports the child inode even if reported on a watched parent. | |
333 | * FS_CREATE reports the modified dir inode and not the created inode. | |
334 | */ | |
335 | static struct inode *fanotify_fid_inode(struct inode *to_tell, u32 event_mask, | |
336 | const void *data, int data_type) | |
337 | { | |
338 | if (event_mask & ALL_FSNOTIFY_DIRENT_EVENTS) | |
339 | return to_tell; | |
aa93bdc5 AG |
340 | |
341 | return (struct inode *)fsnotify_data_inode(data, data_type); | |
83b535d2 AG |
342 | } |
343 | ||
33913997 | 344 | struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, |
77115225 | 345 | struct inode *inode, u32 mask, |
83b535d2 | 346 | const void *data, int data_type, |
cacfb956 | 347 | const struct qstr *file_name, |
77115225 | 348 | __kernel_fsid_t *fsid) |
f083441b | 349 | { |
33913997 | 350 | struct fanotify_event *event = NULL; |
7088f357 | 351 | struct fanotify_fid_event *ffe = NULL; |
cacfb956 | 352 | struct fanotify_name_event *fne = NULL; |
d46eb14b | 353 | gfp_t gfp = GFP_KERNEL_ACCOUNT; |
83b535d2 | 354 | struct inode *id = fanotify_fid_inode(inode, mask, data, data_type); |
aa93bdc5 | 355 | const struct path *path = fsnotify_data_path(data, data_type); |
1f5eaa90 JK |
356 | |
357 | /* | |
358 | * For queues with unlimited length lost events are not expected and | |
359 | * can possibly have security implications. Avoid losing events when | |
ec165450 SB |
360 | * memory is short. For the limited size queues, avoid OOM killer in the |
361 | * target monitoring memcg as it may have security repercussion. | |
1f5eaa90 JK |
362 | */ |
363 | if (group->max_events == UINT_MAX) | |
364 | gfp |= __GFP_NOFAIL; | |
ec165450 SB |
365 | else |
366 | gfp |= __GFP_RETRY_MAYFAIL; | |
f083441b | 367 | |
d46eb14b SB |
368 | /* Whoever is interested in the event, pays for the allocation. */ |
369 | memalloc_use_memcg(group->memcg); | |
370 | ||
6685df31 | 371 | if (fanotify_is_perm_event(mask)) { |
33913997 | 372 | struct fanotify_perm_event *pevent; |
f083441b | 373 | |
1f5eaa90 | 374 | pevent = kmem_cache_alloc(fanotify_perm_event_cachep, gfp); |
f083441b | 375 | if (!pevent) |
d46eb14b | 376 | goto out; |
7088f357 | 377 | |
f083441b | 378 | event = &pevent->fae; |
7088f357 | 379 | event->type = FANOTIFY_EVENT_TYPE_PATH_PERM; |
f083441b | 380 | pevent->response = 0; |
40873284 | 381 | pevent->state = FAN_EVENT_INIT; |
f083441b JK |
382 | goto init; |
383 | } | |
7088f357 | 384 | |
cacfb956 AG |
385 | /* |
386 | * For FAN_DIR_MODIFY event, we report the fid of the directory and | |
387 | * the name of the modified entry. | |
388 | * Allocate an fanotify_name_event struct and copy the name. | |
389 | */ | |
390 | if (mask & FAN_DIR_MODIFY && !(WARN_ON_ONCE(!file_name))) { | |
391 | fne = kmalloc(sizeof(*fne) + file_name->len + 1, gfp); | |
392 | if (!fne) | |
393 | goto out; | |
394 | ||
395 | event = &fne->fae; | |
396 | event->type = FANOTIFY_EVENT_TYPE_FID_NAME; | |
397 | fne->name_len = file_name->len; | |
398 | strcpy(fne->name, file_name->name); | |
399 | goto init; | |
400 | } | |
401 | ||
7088f357 JK |
402 | if (FAN_GROUP_FLAG(group, FAN_REPORT_FID)) { |
403 | ffe = kmem_cache_alloc(fanotify_fid_event_cachep, gfp); | |
404 | if (!ffe) | |
405 | goto out; | |
406 | ||
407 | event = &ffe->fae; | |
408 | event->type = FANOTIFY_EVENT_TYPE_FID; | |
409 | } else { | |
410 | struct fanotify_path_event *pevent; | |
411 | ||
412 | pevent = kmem_cache_alloc(fanotify_path_event_cachep, gfp); | |
413 | if (!pevent) | |
414 | goto out; | |
415 | ||
416 | event = &pevent->fae; | |
417 | event->type = FANOTIFY_EVENT_TYPE_PATH; | |
418 | } | |
419 | ||
cacfb956 | 420 | init: |
f367a62a AG |
421 | /* |
422 | * Use the victim inode instead of the watching inode as the id for | |
423 | * event queue, so event reported on parent is merged with event | |
424 | * reported on child when both directory and child watches exist. | |
425 | */ | |
426 | fsnotify_init_event(&event->fse, (unsigned long)id); | |
a0a92d26 | 427 | event->mask = mask; |
d0a6a87e AG |
428 | if (FAN_GROUP_FLAG(group, FAN_REPORT_TID)) |
429 | event->pid = get_pid(task_pid(current)); | |
430 | else | |
431 | event->pid = get_pid(task_tgid(current)); | |
7088f357 | 432 | |
cacfb956 AG |
433 | if (fsid && fanotify_event_fsid(event)) |
434 | *fanotify_event_fsid(event) = *fsid; | |
435 | ||
436 | if (fanotify_event_object_fh(event)) | |
437 | fanotify_encode_fh(fanotify_event_object_fh(event), id, gfp); | |
438 | ||
439 | if (fanotify_event_dir_fh(event)) | |
440 | fanotify_encode_fh(fanotify_event_dir_fh(event), id, gfp); | |
441 | ||
442 | if (fanotify_event_has_path(event)) { | |
7088f357 JK |
443 | struct path *p = fanotify_event_path(event); |
444 | ||
445 | if (path) { | |
446 | *p = *path; | |
447 | path_get(path); | |
448 | } else { | |
449 | p->mnt = NULL; | |
450 | p->dentry = NULL; | |
451 | } | |
f083441b | 452 | } |
d46eb14b SB |
453 | out: |
454 | memalloc_unuse_memcg(); | |
f083441b JK |
455 | return event; |
456 | } | |
457 | ||
77115225 AG |
458 | /* |
459 | * Get cached fsid of the filesystem containing the object from any connector. | |
460 | * All connectors are supposed to have the same fsid, but we do not verify that | |
461 | * here. | |
462 | */ | |
463 | static __kernel_fsid_t fanotify_get_fsid(struct fsnotify_iter_info *iter_info) | |
464 | { | |
465 | int type; | |
466 | __kernel_fsid_t fsid = {}; | |
467 | ||
468 | fsnotify_foreach_obj_type(type) { | |
b1da6a51 JK |
469 | struct fsnotify_mark_connector *conn; |
470 | ||
77115225 AG |
471 | if (!fsnotify_iter_should_report_type(iter_info, type)) |
472 | continue; | |
473 | ||
b1da6a51 JK |
474 | conn = READ_ONCE(iter_info->marks[type]->connector); |
475 | /* Mark is just getting destroyed or created? */ | |
476 | if (!conn) | |
477 | continue; | |
c285a2f0 AG |
478 | if (!(conn->flags & FSNOTIFY_CONN_FLAG_HAS_FSID)) |
479 | continue; | |
480 | /* Pairs with smp_wmb() in fsnotify_add_mark_list() */ | |
481 | smp_rmb(); | |
b1da6a51 | 482 | fsid = conn->fsid; |
77115225 AG |
483 | if (WARN_ON_ONCE(!fsid.val[0] && !fsid.val[1])) |
484 | continue; | |
485 | return fsid; | |
486 | } | |
487 | ||
488 | return fsid; | |
489 | } | |
490 | ||
7053aee2 JK |
491 | static int fanotify_handle_event(struct fsnotify_group *group, |
492 | struct inode *inode, | |
3cd5eca8 | 493 | u32 mask, const void *data, int data_type, |
e43e9c33 | 494 | const struct qstr *file_name, u32 cookie, |
9385a84d | 495 | struct fsnotify_iter_info *iter_info) |
7053aee2 JK |
496 | { |
497 | int ret = 0; | |
33913997 | 498 | struct fanotify_event *event; |
7053aee2 | 499 | struct fsnotify_event *fsn_event; |
77115225 | 500 | __kernel_fsid_t fsid = {}; |
7053aee2 JK |
501 | |
502 | BUILD_BUG_ON(FAN_ACCESS != FS_ACCESS); | |
503 | BUILD_BUG_ON(FAN_MODIFY != FS_MODIFY); | |
235328d1 | 504 | BUILD_BUG_ON(FAN_ATTRIB != FS_ATTRIB); |
7053aee2 JK |
505 | BUILD_BUG_ON(FAN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE); |
506 | BUILD_BUG_ON(FAN_CLOSE_WRITE != FS_CLOSE_WRITE); | |
507 | BUILD_BUG_ON(FAN_OPEN != FS_OPEN); | |
235328d1 AG |
508 | BUILD_BUG_ON(FAN_MOVED_TO != FS_MOVED_TO); |
509 | BUILD_BUG_ON(FAN_MOVED_FROM != FS_MOVED_FROM); | |
510 | BUILD_BUG_ON(FAN_CREATE != FS_CREATE); | |
511 | BUILD_BUG_ON(FAN_DELETE != FS_DELETE); | |
9e2ba2c3 | 512 | BUILD_BUG_ON(FAN_DIR_MODIFY != FS_DIR_MODIFY); |
235328d1 AG |
513 | BUILD_BUG_ON(FAN_DELETE_SELF != FS_DELETE_SELF); |
514 | BUILD_BUG_ON(FAN_MOVE_SELF != FS_MOVE_SELF); | |
7053aee2 JK |
515 | BUILD_BUG_ON(FAN_EVENT_ON_CHILD != FS_EVENT_ON_CHILD); |
516 | BUILD_BUG_ON(FAN_Q_OVERFLOW != FS_Q_OVERFLOW); | |
517 | BUILD_BUG_ON(FAN_OPEN_PERM != FS_OPEN_PERM); | |
518 | BUILD_BUG_ON(FAN_ACCESS_PERM != FS_ACCESS_PERM); | |
519 | BUILD_BUG_ON(FAN_ONDIR != FS_ISDIR); | |
9b076f1c | 520 | BUILD_BUG_ON(FAN_OPEN_EXEC != FS_OPEN_EXEC); |
66917a31 | 521 | BUILD_BUG_ON(FAN_OPEN_EXEC_PERM != FS_OPEN_EXEC_PERM); |
7053aee2 | 522 | |
f1793699 | 523 | BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 19); |
bdd5a46f | 524 | |
83b535d2 AG |
525 | mask = fanotify_group_event_mask(group, iter_info, mask, data, |
526 | data_type); | |
2d10b230 | 527 | if (!mask) |
83c4c4b0 JK |
528 | return 0; |
529 | ||
7053aee2 JK |
530 | pr_debug("%s: group=%p inode=%p mask=%x\n", __func__, group, inode, |
531 | mask); | |
532 | ||
6685df31 | 533 | if (fanotify_is_perm_event(mask)) { |
f37650f1 MS |
534 | /* |
535 | * fsnotify_prepare_user_wait() fails if we race with mark | |
536 | * deletion. Just let the operation pass in that case. | |
537 | */ | |
538 | if (!fsnotify_prepare_user_wait(iter_info)) | |
539 | return 0; | |
540 | } | |
f37650f1 | 541 | |
b1da6a51 | 542 | if (FAN_GROUP_FLAG(group, FAN_REPORT_FID)) { |
77115225 | 543 | fsid = fanotify_get_fsid(iter_info); |
b1da6a51 JK |
544 | /* Racing with mark destruction or creation? */ |
545 | if (!fsid.val[0] && !fsid.val[1]) | |
546 | return 0; | |
547 | } | |
77115225 | 548 | |
83b535d2 | 549 | event = fanotify_alloc_event(group, inode, mask, data, data_type, |
cacfb956 | 550 | file_name, &fsid); |
f37650f1 | 551 | ret = -ENOMEM; |
7b1f6417 JK |
552 | if (unlikely(!event)) { |
553 | /* | |
554 | * We don't queue overflow events for permission events as | |
555 | * there the access is denied and so no event is in fact lost. | |
556 | */ | |
557 | if (!fanotify_is_perm_event(mask)) | |
558 | fsnotify_queue_overflow(group); | |
f37650f1 | 559 | goto finish; |
7b1f6417 | 560 | } |
7053aee2 JK |
561 | |
562 | fsn_event = &event->fse; | |
8ba8fa91 | 563 | ret = fsnotify_add_event(group, fsn_event, fanotify_merge); |
83c0e1b4 | 564 | if (ret) { |
482ef06c | 565 | /* Permission events shouldn't be merged */ |
23c9deeb | 566 | BUG_ON(ret == 1 && mask & FANOTIFY_PERM_EVENTS); |
7053aee2 JK |
567 | /* Our event wasn't used in the end. Free it. */ |
568 | fsnotify_destroy_event(group, fsn_event); | |
482ef06c | 569 | |
f37650f1 | 570 | ret = 0; |
6685df31 | 571 | } else if (fanotify_is_perm_event(mask)) { |
7088f357 | 572 | ret = fanotify_get_response(group, FANOTIFY_PERM(event), |
05f0e387 | 573 | iter_info); |
85816794 | 574 | } |
f37650f1 | 575 | finish: |
6685df31 | 576 | if (fanotify_is_perm_event(mask)) |
f37650f1 | 577 | fsnotify_finish_user_wait(iter_info); |
6685df31 | 578 | |
7053aee2 JK |
579 | return ret; |
580 | } | |
581 | ||
4afeff85 EP |
582 | static void fanotify_free_group_priv(struct fsnotify_group *group) |
583 | { | |
584 | struct user_struct *user; | |
585 | ||
586 | user = group->fanotify_data.user; | |
587 | atomic_dec(&user->fanotify_listeners); | |
588 | free_uid(user); | |
589 | } | |
590 | ||
7088f357 JK |
591 | static void fanotify_free_path_event(struct fanotify_event *event) |
592 | { | |
593 | path_put(fanotify_event_path(event)); | |
594 | kmem_cache_free(fanotify_path_event_cachep, FANOTIFY_PE(event)); | |
595 | } | |
596 | ||
597 | static void fanotify_free_perm_event(struct fanotify_event *event) | |
598 | { | |
599 | path_put(fanotify_event_path(event)); | |
600 | kmem_cache_free(fanotify_perm_event_cachep, FANOTIFY_PERM(event)); | |
601 | } | |
602 | ||
603 | static void fanotify_free_fid_event(struct fanotify_event *event) | |
604 | { | |
605 | struct fanotify_fid_event *ffe = FANOTIFY_FE(event); | |
606 | ||
607 | if (fanotify_fh_has_ext_buf(&ffe->object_fh)) | |
608 | kfree(fanotify_fh_ext_buf(&ffe->object_fh)); | |
609 | kmem_cache_free(fanotify_fid_event_cachep, ffe); | |
610 | } | |
611 | ||
cacfb956 AG |
612 | static void fanotify_free_name_event(struct fanotify_event *event) |
613 | { | |
614 | struct fanotify_name_event *fne = FANOTIFY_NE(event); | |
615 | ||
616 | if (fanotify_fh_has_ext_buf(&fne->dir_fh)) | |
617 | kfree(fanotify_fh_ext_buf(&fne->dir_fh)); | |
618 | kfree(fne); | |
619 | } | |
620 | ||
7053aee2 JK |
621 | static void fanotify_free_event(struct fsnotify_event *fsn_event) |
622 | { | |
33913997 | 623 | struct fanotify_event *event; |
7053aee2 JK |
624 | |
625 | event = FANOTIFY_E(fsn_event); | |
d0a6a87e | 626 | put_pid(event->pid); |
7088f357 JK |
627 | switch (event->type) { |
628 | case FANOTIFY_EVENT_TYPE_PATH: | |
629 | fanotify_free_path_event(event); | |
630 | break; | |
631 | case FANOTIFY_EVENT_TYPE_PATH_PERM: | |
632 | fanotify_free_perm_event(event); | |
633 | break; | |
634 | case FANOTIFY_EVENT_TYPE_FID: | |
635 | fanotify_free_fid_event(event); | |
636 | break; | |
cacfb956 AG |
637 | case FANOTIFY_EVENT_TYPE_FID_NAME: |
638 | fanotify_free_name_event(event); | |
639 | break; | |
7088f357 JK |
640 | default: |
641 | WARN_ON_ONCE(1); | |
f083441b | 642 | } |
7053aee2 JK |
643 | } |
644 | ||
054c636e JK |
645 | static void fanotify_free_mark(struct fsnotify_mark *fsn_mark) |
646 | { | |
647 | kmem_cache_free(fanotify_mark_cache, fsn_mark); | |
648 | } | |
649 | ||
ff0b16a9 EP |
650 | const struct fsnotify_ops fanotify_fsnotify_ops = { |
651 | .handle_event = fanotify_handle_event, | |
4afeff85 | 652 | .free_group_priv = fanotify_free_group_priv, |
7053aee2 | 653 | .free_event = fanotify_free_event, |
054c636e | 654 | .free_mark = fanotify_free_mark, |
ff0b16a9 | 655 | }; |