tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
net: split out functions related to registering inflight socket files
We need this functionality for the io_uring file registration, but
we cannot rely on it since CONFIG_UNIX can be modular. Move the helpers
to a separate file, that's always builtin to the kernel if CONFIG_UNIX is
m/y.
No functional changes in this patch, just moving code around.
Reviewed-by: Hannes Reinecke <hare@suse.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
+174
-131
+1
include/net/af_unix.h
+1
include/net/af_unix.h
···
10
10
11
11
void unix_inflight(struct user_struct *user, struct file *fp);
12
12
void unix_notinflight(struct user_struct *user, struct file *fp);
13
+
void unix_destruct_scm(struct sk_buff *skb);
13
14
void unix_gc(void);
14
15
void wait_for_unix_gc(void);
15
16
struct sock *unix_get_socket(struct file *filp);
+1
-1
net/Makefile
+1
-1
net/Makefile
+5
net/unix/Kconfig
+5
net/unix/Kconfig
+2
net/unix/Makefile
+2
net/unix/Makefile
+2
-61
net/unix/af_unix.c
+2
-61
net/unix/af_unix.c
···
119
119
#include <linux/freezer.h>
120
120
#include <linux/file.h>
121
121
122
+
#include "scm.h"
123
+
122
124
struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];
123
125
EXPORT_SYMBOL_GPL(unix_socket_table);
124
126
DEFINE_SPINLOCK(unix_table_lock);
···
1486
1484
sock_put(sk);
1487
1485
out:
1488
1486
return err;
1489
-
}
1490
-
1491
-
static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1492
-
{
1493
-
int i;
1494
-
1495
-
scm->fp = UNIXCB(skb).fp;
1496
-
UNIXCB(skb).fp = NULL;
1497
-
1498
-
for (i = scm->fp->count-1; i >= 0; i--)
1499
-
unix_notinflight(scm->fp->user, scm->fp->fp[i]);
1500
-
}
1501
-
1502
-
static void unix_destruct_scm(struct sk_buff *skb)
1503
-
{
1504
-
struct scm_cookie scm;
1505
-
memset(&scm, 0, sizeof(scm));
1506
-
scm.pid = UNIXCB(skb).pid;
1507
-
if (UNIXCB(skb).fp)
1508
-
unix_detach_fds(&scm, skb);
1509
-
1510
-
/* Alas, it calls VFS */
1511
-
/* So fscking what? fput() had been SMP-safe since the last Summer */
1512
-
scm_destroy(&scm);
1513
-
sock_wfree(skb);
1514
-
}
1515
-
1516
-
/*
1517
-
* The "user->unix_inflight" variable is protected by the garbage
1518
-
* collection lock, and we just read it locklessly here. If you go
1519
-
* over the limit, there might be a tiny race in actually noticing
1520
-
* it across threads. Tough.
1521
-
*/
1522
-
static inline bool too_many_unix_fds(struct task_struct *p)
1523
-
{
1524
-
struct user_struct *user = current_user();
1525
-
1526
-
if (unlikely(user->unix_inflight > task_rlimit(p, RLIMIT_NOFILE)))
1527
-
return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN);
1528
-
return false;
1529
-
}
1530
-
1531
-
static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1532
-
{
1533
-
int i;
1534
-
1535
-
if (too_many_unix_fds(current))
1536
-
return -ETOOMANYREFS;
1537
-
1538
-
/*
1539
-
* Need to duplicate file references for the sake of garbage
1540
-
* collection. Otherwise a socket in the fps might become a
1541
-
* candidate for GC while the skb is not yet queued.
1542
-
*/
1543
-
UNIXCB(skb).fp = scm_fp_dup(scm->fp);
1544
-
if (!UNIXCB(skb).fp)
1545
-
return -ENOMEM;
1546
-
1547
-
for (i = scm->fp->count - 1; i >= 0; i--)
1548
-
unix_inflight(scm->fp->user, scm->fp->fp[i]);
1549
-
return 0;
1550
1487
}
1551
1488
1552
1489
static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
+2
-69
net/unix/garbage.c
+2
-69
net/unix/garbage.c
···
86
86
#include <net/scm.h>
87
87
#include <net/tcp_states.h>
88
88
89
+
#include "scm.h"
90
+
89
91
/* Internal data structures and random procedures: */
90
92
91
-
static LIST_HEAD(gc_inflight_list);
92
93
static LIST_HEAD(gc_candidates);
93
-
static DEFINE_SPINLOCK(unix_gc_lock);
94
94
static DECLARE_WAIT_QUEUE_HEAD(unix_gc_wait);
95
-
96
-
unsigned int unix_tot_inflight;
97
-
98
-
struct sock *unix_get_socket(struct file *filp)
99
-
{
100
-
struct sock *u_sock = NULL;
101
-
struct inode *inode = file_inode(filp);
102
-
103
-
/* Socket ? */
104
-
if (S_ISSOCK(inode->i_mode) && !(filp->f_mode & FMODE_PATH)) {
105
-
struct socket *sock = SOCKET_I(inode);
106
-
struct sock *s = sock->sk;
107
-
108
-
/* PF_UNIX ? */
109
-
if (s && sock->ops && sock->ops->family == PF_UNIX)
110
-
u_sock = s;
111
-
} else {
112
-
/* Could be an io_uring instance */
113
-
u_sock = io_uring_get_socket(filp);
114
-
}
115
-
return u_sock;
116
-
}
117
-
118
-
/* Keep the number of times in flight count for the file
119
-
* descriptor if it is for an AF_UNIX socket.
120
-
*/
121
-
122
-
void unix_inflight(struct user_struct *user, struct file *fp)
123
-
{
124
-
struct sock *s = unix_get_socket(fp);
125
-
126
-
spin_lock(&unix_gc_lock);
127
-
128
-
if (s) {
129
-
struct unix_sock *u = unix_sk(s);
130
-
131
-
if (atomic_long_inc_return(&u->inflight) == 1) {
132
-
BUG_ON(!list_empty(&u->link));
133
-
list_add_tail(&u->link, &gc_inflight_list);
134
-
} else {
135
-
BUG_ON(list_empty(&u->link));
136
-
}
137
-
unix_tot_inflight++;
138
-
}
139
-
user->unix_inflight++;
140
-
spin_unlock(&unix_gc_lock);
141
-
}
142
-
143
-
void unix_notinflight(struct user_struct *user, struct file *fp)
144
-
{
145
-
struct sock *s = unix_get_socket(fp);
146
-
147
-
spin_lock(&unix_gc_lock);
148
-
149
-
if (s) {
150
-
struct unix_sock *u = unix_sk(s);
151
-
152
-
BUG_ON(!atomic_long_read(&u->inflight));
153
-
BUG_ON(list_empty(&u->link));
154
-
155
-
if (atomic_long_dec_and_test(&u->inflight))
156
-
list_del_init(&u->link);
157
-
unix_tot_inflight--;
158
-
}
159
-
user->unix_inflight--;
160
-
spin_unlock(&unix_gc_lock);
161
-
}
162
95
163
96
static void scan_inflight(struct sock *x, void (*func)(struct unix_sock *),
164
97
struct sk_buff_head *hitlist)
+151
net/unix/scm.c
+151
net/unix/scm.c
···
1
+
// SPDX-License-Identifier: GPL-2.0
2
+
#include <linux/module.h>
3
+
#include <linux/kernel.h>
4
+
#include <linux/string.h>
5
+
#include <linux/socket.h>
6
+
#include <linux/net.h>
7
+
#include <linux/fs.h>
8
+
#include <net/af_unix.h>
9
+
#include <net/scm.h>
10
+
#include <linux/init.h>
11
+
12
+
#include "scm.h"
13
+
14
+
unsigned int unix_tot_inflight;
15
+
EXPORT_SYMBOL(unix_tot_inflight);
16
+
17
+
LIST_HEAD(gc_inflight_list);
18
+
EXPORT_SYMBOL(gc_inflight_list);
19
+
20
+
DEFINE_SPINLOCK(unix_gc_lock);
21
+
EXPORT_SYMBOL(unix_gc_lock);
22
+
23
+
struct sock *unix_get_socket(struct file *filp)
24
+
{
25
+
struct sock *u_sock = NULL;
26
+
struct inode *inode = file_inode(filp);
27
+
28
+
/* Socket ? */
29
+
if (S_ISSOCK(inode->i_mode) && !(filp->f_mode & FMODE_PATH)) {
30
+
struct socket *sock = SOCKET_I(inode);
31
+
struct sock *s = sock->sk;
32
+
33
+
/* PF_UNIX ? */
34
+
if (s && sock->ops && sock->ops->family == PF_UNIX)
35
+
u_sock = s;
36
+
} else {
37
+
/* Could be an io_uring instance */
38
+
u_sock = io_uring_get_socket(filp);
39
+
}
40
+
return u_sock;
41
+
}
42
+
EXPORT_SYMBOL(unix_get_socket);
43
+
44
+
/* Keep the number of times in flight count for the file
45
+
* descriptor if it is for an AF_UNIX socket.
46
+
*/
47
+
void unix_inflight(struct user_struct *user, struct file *fp)
48
+
{
49
+
struct sock *s = unix_get_socket(fp);
50
+
51
+
spin_lock(&unix_gc_lock);
52
+
53
+
if (s) {
54
+
struct unix_sock *u = unix_sk(s);
55
+
56
+
if (atomic_long_inc_return(&u->inflight) == 1) {
57
+
BUG_ON(!list_empty(&u->link));
58
+
list_add_tail(&u->link, &gc_inflight_list);
59
+
} else {
60
+
BUG_ON(list_empty(&u->link));
61
+
}
62
+
unix_tot_inflight++;
63
+
}
64
+
user->unix_inflight++;
65
+
spin_unlock(&unix_gc_lock);
66
+
}
67
+
68
+
void unix_notinflight(struct user_struct *user, struct file *fp)
69
+
{
70
+
struct sock *s = unix_get_socket(fp);
71
+
72
+
spin_lock(&unix_gc_lock);
73
+
74
+
if (s) {
75
+
struct unix_sock *u = unix_sk(s);
76
+
77
+
BUG_ON(!atomic_long_read(&u->inflight));
78
+
BUG_ON(list_empty(&u->link));
79
+
80
+
if (atomic_long_dec_and_test(&u->inflight))
81
+
list_del_init(&u->link);
82
+
unix_tot_inflight--;
83
+
}
84
+
user->unix_inflight--;
85
+
spin_unlock(&unix_gc_lock);
86
+
}
87
+
88
+
/*
89
+
* The "user->unix_inflight" variable is protected by the garbage
90
+
* collection lock, and we just read it locklessly here. If you go
91
+
* over the limit, there might be a tiny race in actually noticing
92
+
* it across threads. Tough.
93
+
*/
94
+
static inline bool too_many_unix_fds(struct task_struct *p)
95
+
{
96
+
struct user_struct *user = current_user();
97
+
98
+
if (unlikely(user->unix_inflight > task_rlimit(p, RLIMIT_NOFILE)))
99
+
return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN);
100
+
return false;
101
+
}
102
+
103
+
int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
104
+
{
105
+
int i;
106
+
107
+
if (too_many_unix_fds(current))
108
+
return -ETOOMANYREFS;
109
+
110
+
/*
111
+
* Need to duplicate file references for the sake of garbage
112
+
* collection. Otherwise a socket in the fps might become a
113
+
* candidate for GC while the skb is not yet queued.
114
+
*/
115
+
UNIXCB(skb).fp = scm_fp_dup(scm->fp);
116
+
if (!UNIXCB(skb).fp)
117
+
return -ENOMEM;
118
+
119
+
for (i = scm->fp->count - 1; i >= 0; i--)
120
+
unix_inflight(scm->fp->user, scm->fp->fp[i]);
121
+
return 0;
122
+
}
123
+
EXPORT_SYMBOL(unix_attach_fds);
124
+
125
+
void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
126
+
{
127
+
int i;
128
+
129
+
scm->fp = UNIXCB(skb).fp;
130
+
UNIXCB(skb).fp = NULL;
131
+
132
+
for (i = scm->fp->count-1; i >= 0; i--)
133
+
unix_notinflight(scm->fp->user, scm->fp->fp[i]);
134
+
}
135
+
EXPORT_SYMBOL(unix_detach_fds);
136
+
137
+
void unix_destruct_scm(struct sk_buff *skb)
138
+
{
139
+
struct scm_cookie scm;
140
+
141
+
memset(&scm, 0, sizeof(scm));
142
+
scm.pid = UNIXCB(skb).pid;
143
+
if (UNIXCB(skb).fp)
144
+
unix_detach_fds(&scm, skb);
145
+
146
+
/* Alas, it calls VFS */
147
+
/* So fscking what? fput() had been SMP-safe since the last Summer */
148
+
scm_destroy(&scm);
149
+
sock_wfree(skb);
150
+
}
151
+
EXPORT_SYMBOL(unix_destruct_scm);
+10
net/unix/scm.h
+10
net/unix/scm.h
···
1
+
#ifndef NET_UNIX_SCM_H
2
+
#define NET_UNIX_SCM_H
3
+
4
+
extern struct list_head gc_inflight_list;
5
+
extern spinlock_t unix_gc_lock;
6
+
7
+
int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb);
8
+
void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb);
9
+
10
+
#endif