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
|
/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/fsnotify_backend.h>
#include <linux/path.h>
#include <linux/slab.h>
#include <linux/exportfs.h>
extern struct kmem_cache *fanotify_mark_cache;
extern struct kmem_cache *fanotify_event_cachep;
extern struct kmem_cache *fanotify_perm_event_cachep;
/* Possible states of the permission event */
enum {
FAN_EVENT_INIT,
FAN_EVENT_REPORTED,
FAN_EVENT_ANSWERED,
FAN_EVENT_CANCELED,
};
/*
* 3 dwords are sufficient for most local fs (64bit ino, 32bit generation).
* For 32bit arch, fid increases the size of fanotify_event by 12 bytes and
* fh_* fields increase the size of fanotify_event by another 4 bytes.
* For 64bit arch, fid increases the size of fanotify_fid by 8 bytes and
* fh_* fields are packed in a hole after mask.
*/
#if BITS_PER_LONG == 32
#define FANOTIFY_INLINE_FH_LEN (3 << 2)
#else
#define FANOTIFY_INLINE_FH_LEN (4 << 2)
#endif
struct fanotify_fid {
__kernel_fsid_t fsid;
union {
unsigned char fh[FANOTIFY_INLINE_FH_LEN];
unsigned char *ext_fh;
};
};
static inline void *fanotify_fid_fh(struct fanotify_fid *fid,
unsigned int fh_len)
{
return fh_len <= FANOTIFY_INLINE_FH_LEN ? fid->fh : fid->ext_fh;
}
static inline bool fanotify_fid_equal(struct fanotify_fid *fid1,
struct fanotify_fid *fid2,
unsigned int fh_len)
{
return fid1->fsid.val[0] == fid2->fsid.val[0] &&
fid1->fsid.val[1] == fid2->fsid.val[1] &&
!memcmp(fanotify_fid_fh(fid1, fh_len),
fanotify_fid_fh(fid2, fh_len), fh_len);
}
/*
* Structure for normal fanotify events. It gets allocated in
* fanotify_handle_event() and freed when the information is retrieved by
* userspace
*/
struct fanotify_event {
struct fsnotify_event fse;
u32 mask;
/*
* Those fields are outside fanotify_fid to pack fanotify_event nicely
* on 64bit arch and to use fh_type as an indication of whether path
* or fid are used in the union:
* FILEID_ROOT (0) for path, > 0 for fid, FILEID_INVALID for neither.
*/
u8 fh_type;
u8 fh_len;
u16 pad;
union {
/*
* We hold ref to this path so it may be dereferenced at any
* point during this object's lifetime
*/
struct path path;
/*
* With FAN_REPORT_FID, we do not hold any reference on the
* victim object. Instead we store its NFS file handle and its
* filesystem's fsid as a unique identifier.
*/
struct fanotify_fid fid;
};
struct pid *pid;
};
static inline bool fanotify_event_has_path(struct fanotify_event *event)
{
return event->fh_type == FILEID_ROOT;
}
static inline bool fanotify_event_has_fid(struct fanotify_event *event)
{
return event->fh_type != FILEID_ROOT &&
event->fh_type != FILEID_INVALID;
}
static inline bool fanotify_event_has_ext_fh(struct fanotify_event *event)
{
return fanotify_event_has_fid(event) &&
event->fh_len > FANOTIFY_INLINE_FH_LEN;
}
static inline void *fanotify_event_fh(struct fanotify_event *event)
{
return fanotify_fid_fh(&event->fid, event->fh_len);
}
/*
* Structure for permission fanotify events. It gets allocated and freed in
* fanotify_handle_event() since we wait there for user response. When the
* information is retrieved by userspace the structure is moved from
* group->notification_list to group->fanotify_data.access_list to wait for
* user response.
*/
struct fanotify_perm_event {
struct fanotify_event fae;
unsigned short response; /* userspace answer to the event */
unsigned short state; /* state of the event */
int fd; /* fd we passed to userspace for this event */
};
static inline struct fanotify_perm_event *
FANOTIFY_PE(struct fsnotify_event *fse)
{
return container_of(fse, struct fanotify_perm_event, fae.fse);
}
static inline bool fanotify_is_perm_event(u32 mask)
{
return IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS) &&
mask & FANOTIFY_PERM_EVENTS;
}
static inline struct fanotify_event *FANOTIFY_E(struct fsnotify_event *fse)
{
return container_of(fse, struct fanotify_event, fse);
}
struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
struct inode *inode, u32 mask,
const void *data, int data_type,
__kernel_fsid_t *fsid);
|
