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Commit | Line | Data |
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33d3dfff | 1 | #include <linux/fanotify.h> |
ff0b16a9 EP |
2 | #include <linux/fdtable.h> |
3 | #include <linux/fsnotify_backend.h> | |
4 | #include <linux/init.h> | |
9e66e423 | 5 | #include <linux/jiffies.h> |
ff0b16a9 | 6 | #include <linux/kernel.h> /* UINT_MAX */ |
1c529063 | 7 | #include <linux/mount.h> |
9e66e423 | 8 | #include <linux/sched.h> |
5b825c3a | 9 | #include <linux/sched/user.h> |
ff0b16a9 | 10 | #include <linux/types.h> |
9e66e423 | 11 | #include <linux/wait.h> |
ff0b16a9 | 12 | |
7053aee2 JK |
13 | #include "fanotify.h" |
14 | ||
15 | static bool should_merge(struct fsnotify_event *old_fsn, | |
16 | struct fsnotify_event *new_fsn) | |
767cd46c | 17 | { |
7053aee2 | 18 | struct fanotify_event_info *old, *new; |
767cd46c | 19 | |
7053aee2 JK |
20 | pr_debug("%s: old=%p new=%p\n", __func__, old_fsn, new_fsn); |
21 | old = FANOTIFY_E(old_fsn); | |
22 | new = FANOTIFY_E(new_fsn); | |
23 | ||
24 | if (old_fsn->inode == new_fsn->inode && old->tgid == new->tgid && | |
25 | old->path.mnt == new->path.mnt && | |
26 | old->path.dentry == new->path.dentry) | |
27 | return true; | |
767cd46c EP |
28 | return false; |
29 | } | |
30 | ||
f70ab54c | 31 | /* and the list better be locked by something too! */ |
83c0e1b4 | 32 | static int fanotify_merge(struct list_head *list, struct fsnotify_event *event) |
767cd46c | 33 | { |
7053aee2 | 34 | struct fsnotify_event *test_event; |
767cd46c EP |
35 | |
36 | pr_debug("%s: list=%p event=%p\n", __func__, list, event); | |
37 | ||
13116dfd JK |
38 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
39 | /* | |
40 | * Don't merge a permission event with any other event so that we know | |
41 | * the event structure we have created in fanotify_handle_event() is the | |
42 | * one we should check for permission response. | |
43 | */ | |
44 | if (event->mask & FAN_ALL_PERM_EVENTS) | |
83c0e1b4 | 45 | return 0; |
13116dfd JK |
46 | #endif |
47 | ||
7053aee2 JK |
48 | list_for_each_entry_reverse(test_event, list, list) { |
49 | if (should_merge(test_event, event)) { | |
6c71100d KM |
50 | test_event->mask |= event->mask; |
51 | return 1; | |
a12a7dd3 EP |
52 | } |
53 | } | |
f70ab54c | 54 | |
6c71100d | 55 | return 0; |
767cd46c EP |
56 | } |
57 | ||
9e66e423 | 58 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
f083441b JK |
59 | static int fanotify_get_response(struct fsnotify_group *group, |
60 | struct fanotify_perm_event_info *event) | |
9e66e423 EP |
61 | { |
62 | int ret; | |
63 | ||
64 | pr_debug("%s: group=%p event=%p\n", __func__, group, event); | |
65 | ||
96d41019 | 66 | wait_event(group->fanotify_data.access_waitq, event->response); |
9e66e423 EP |
67 | |
68 | /* userspace responded, convert to something usable */ | |
9e66e423 EP |
69 | switch (event->response) { |
70 | case FAN_ALLOW: | |
71 | ret = 0; | |
72 | break; | |
73 | case FAN_DENY: | |
74 | default: | |
75 | ret = -EPERM; | |
76 | } | |
77 | event->response = 0; | |
9e66e423 | 78 | |
b2d87909 EP |
79 | pr_debug("%s: group=%p event=%p about to return ret=%d\n", __func__, |
80 | group, event, ret); | |
81 | ||
9e66e423 EP |
82 | return ret; |
83 | } | |
84 | #endif | |
85 | ||
83c4c4b0 | 86 | static bool fanotify_should_send_event(struct fsnotify_mark *inode_mark, |
1968f5ee | 87 | struct fsnotify_mark *vfsmnt_mark, |
83c4c4b0 | 88 | u32 event_mask, |
3cd5eca8 | 89 | const void *data, int data_type) |
1c529063 | 90 | { |
1968f5ee | 91 | __u32 marks_mask, marks_ignored_mask; |
3cd5eca8 | 92 | const struct path *path = data; |
1968f5ee | 93 | |
83c4c4b0 JK |
94 | pr_debug("%s: inode_mark=%p vfsmnt_mark=%p mask=%x data=%p" |
95 | " data_type=%d\n", __func__, inode_mark, vfsmnt_mark, | |
96 | event_mask, data, data_type); | |
1968f5ee | 97 | |
1c529063 | 98 | /* if we don't have enough info to send an event to userspace say no */ |
2069601b | 99 | if (data_type != FSNOTIFY_EVENT_PATH) |
1c529063 EP |
100 | return false; |
101 | ||
e1c048ba | 102 | /* sorry, fanotify only gives a damn about files and dirs */ |
e36cb0b8 | 103 | if (!d_is_reg(path->dentry) && |
54f2a2f4 | 104 | !d_can_lookup(path->dentry)) |
e1c048ba EP |
105 | return false; |
106 | ||
1968f5ee EP |
107 | if (inode_mark && vfsmnt_mark) { |
108 | marks_mask = (vfsmnt_mark->mask | inode_mark->mask); | |
109 | marks_ignored_mask = (vfsmnt_mark->ignored_mask | inode_mark->ignored_mask); | |
110 | } else if (inode_mark) { | |
111 | /* | |
112 | * if the event is for a child and this inode doesn't care about | |
113 | * events on the child, don't send it! | |
114 | */ | |
115 | if ((event_mask & FS_EVENT_ON_CHILD) && | |
116 | !(inode_mark->mask & FS_EVENT_ON_CHILD)) | |
117 | return false; | |
118 | marks_mask = inode_mark->mask; | |
119 | marks_ignored_mask = inode_mark->ignored_mask; | |
120 | } else if (vfsmnt_mark) { | |
121 | marks_mask = vfsmnt_mark->mask; | |
122 | marks_ignored_mask = vfsmnt_mark->ignored_mask; | |
123 | } else { | |
124 | BUG(); | |
125 | } | |
126 | ||
e36cb0b8 | 127 | if (d_is_dir(path->dentry) && |
66ba93c0 | 128 | !(marks_mask & FS_ISDIR & ~marks_ignored_mask)) |
8fcd6528 EP |
129 | return false; |
130 | ||
b3c1030d SP |
131 | if (event_mask & FAN_ALL_OUTGOING_EVENTS & marks_mask & |
132 | ~marks_ignored_mask) | |
1968f5ee EP |
133 | return true; |
134 | ||
135 | return false; | |
1c529063 EP |
136 | } |
137 | ||
f083441b | 138 | struct fanotify_event_info *fanotify_alloc_event(struct inode *inode, u32 mask, |
3cd5eca8 | 139 | const struct path *path) |
f083441b JK |
140 | { |
141 | struct fanotify_event_info *event; | |
142 | ||
143 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS | |
144 | if (mask & FAN_ALL_PERM_EVENTS) { | |
145 | struct fanotify_perm_event_info *pevent; | |
146 | ||
147 | pevent = kmem_cache_alloc(fanotify_perm_event_cachep, | |
148 | GFP_KERNEL); | |
149 | if (!pevent) | |
150 | return NULL; | |
151 | event = &pevent->fae; | |
152 | pevent->response = 0; | |
153 | goto init; | |
154 | } | |
155 | #endif | |
156 | event = kmem_cache_alloc(fanotify_event_cachep, GFP_KERNEL); | |
157 | if (!event) | |
158 | return NULL; | |
159 | init: __maybe_unused | |
160 | fsnotify_init_event(&event->fse, inode, mask); | |
161 | event->tgid = get_pid(task_tgid(current)); | |
162 | if (path) { | |
163 | event->path = *path; | |
164 | path_get(&event->path); | |
165 | } else { | |
166 | event->path.mnt = NULL; | |
167 | event->path.dentry = NULL; | |
168 | } | |
169 | return event; | |
170 | } | |
171 | ||
7053aee2 JK |
172 | static int fanotify_handle_event(struct fsnotify_group *group, |
173 | struct inode *inode, | |
174 | struct fsnotify_mark *inode_mark, | |
175 | struct fsnotify_mark *fanotify_mark, | |
3cd5eca8 | 176 | u32 mask, const void *data, int data_type, |
45a22f4c | 177 | const unsigned char *file_name, u32 cookie) |
7053aee2 JK |
178 | { |
179 | int ret = 0; | |
180 | struct fanotify_event_info *event; | |
181 | struct fsnotify_event *fsn_event; | |
7053aee2 JK |
182 | |
183 | BUILD_BUG_ON(FAN_ACCESS != FS_ACCESS); | |
184 | BUILD_BUG_ON(FAN_MODIFY != FS_MODIFY); | |
185 | BUILD_BUG_ON(FAN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE); | |
186 | BUILD_BUG_ON(FAN_CLOSE_WRITE != FS_CLOSE_WRITE); | |
187 | BUILD_BUG_ON(FAN_OPEN != FS_OPEN); | |
188 | BUILD_BUG_ON(FAN_EVENT_ON_CHILD != FS_EVENT_ON_CHILD); | |
189 | BUILD_BUG_ON(FAN_Q_OVERFLOW != FS_Q_OVERFLOW); | |
190 | BUILD_BUG_ON(FAN_OPEN_PERM != FS_OPEN_PERM); | |
191 | BUILD_BUG_ON(FAN_ACCESS_PERM != FS_ACCESS_PERM); | |
192 | BUILD_BUG_ON(FAN_ONDIR != FS_ISDIR); | |
193 | ||
83c4c4b0 JK |
194 | if (!fanotify_should_send_event(inode_mark, fanotify_mark, mask, data, |
195 | data_type)) | |
196 | return 0; | |
197 | ||
7053aee2 JK |
198 | pr_debug("%s: group=%p inode=%p mask=%x\n", __func__, group, inode, |
199 | mask); | |
200 | ||
f083441b | 201 | event = fanotify_alloc_event(inode, mask, data); |
7053aee2 JK |
202 | if (unlikely(!event)) |
203 | return -ENOMEM; | |
204 | ||
205 | fsn_event = &event->fse; | |
8ba8fa91 | 206 | ret = fsnotify_add_event(group, fsn_event, fanotify_merge); |
83c0e1b4 | 207 | if (ret) { |
482ef06c JK |
208 | /* Permission events shouldn't be merged */ |
209 | BUG_ON(ret == 1 && mask & FAN_ALL_PERM_EVENTS); | |
7053aee2 JK |
210 | /* Our event wasn't used in the end. Free it. */ |
211 | fsnotify_destroy_event(group, fsn_event); | |
482ef06c JK |
212 | |
213 | return 0; | |
7053aee2 JK |
214 | } |
215 | ||
216 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS | |
85816794 | 217 | if (mask & FAN_ALL_PERM_EVENTS) { |
f083441b | 218 | ret = fanotify_get_response(group, FANOTIFY_PE(fsn_event)); |
85816794 JK |
219 | fsnotify_destroy_event(group, fsn_event); |
220 | } | |
7053aee2 JK |
221 | #endif |
222 | return ret; | |
223 | } | |
224 | ||
4afeff85 EP |
225 | static void fanotify_free_group_priv(struct fsnotify_group *group) |
226 | { | |
227 | struct user_struct *user; | |
228 | ||
229 | user = group->fanotify_data.user; | |
230 | atomic_dec(&user->fanotify_listeners); | |
231 | free_uid(user); | |
232 | } | |
233 | ||
7053aee2 JK |
234 | static void fanotify_free_event(struct fsnotify_event *fsn_event) |
235 | { | |
236 | struct fanotify_event_info *event; | |
237 | ||
238 | event = FANOTIFY_E(fsn_event); | |
239 | path_put(&event->path); | |
240 | put_pid(event->tgid); | |
f083441b JK |
241 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
242 | if (fsn_event->mask & FAN_ALL_PERM_EVENTS) { | |
243 | kmem_cache_free(fanotify_perm_event_cachep, | |
244 | FANOTIFY_PE(fsn_event)); | |
245 | return; | |
246 | } | |
247 | #endif | |
7053aee2 JK |
248 | kmem_cache_free(fanotify_event_cachep, event); |
249 | } | |
250 | ||
ff0b16a9 EP |
251 | const struct fsnotify_ops fanotify_fsnotify_ops = { |
252 | .handle_event = fanotify_handle_event, | |
4afeff85 | 253 | .free_group_priv = fanotify_free_group_priv, |
7053aee2 | 254 | .free_event = fanotify_free_event, |
ff0b16a9 | 255 | }; |