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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
14unsigned int unix_tot_inflight;
15EXPORT_SYMBOL(unix_tot_inflight);
16
17LIST_HEAD(gc_inflight_list);
18EXPORT_SYMBOL(gc_inflight_list);
19
20DEFINE_SPINLOCK(unix_gc_lock);
21EXPORT_SYMBOL(unix_gc_lock);
22
23struct 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}
42EXPORT_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 */
47void 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
68void 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 */
94static 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
103int 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}
123EXPORT_SYMBOL(unix_attach_fds);
124
125void 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}
135EXPORT_SYMBOL(unix_detach_fds);
136
137void 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}
151EXPORT_SYMBOL(unix_destruct_scm);
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
14unsigned int unix_tot_inflight;
15EXPORT_SYMBOL(unix_tot_inflight);
16
17LIST_HEAD(gc_inflight_list);
18EXPORT_SYMBOL(gc_inflight_list);
19
20DEFINE_SPINLOCK(unix_gc_lock);
21EXPORT_SYMBOL(unix_gc_lock);
22
23struct 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}
42EXPORT_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 */
47void 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
68void 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 */
94static 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
103int 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}
123EXPORT_SYMBOL(unix_attach_fds);
124
125void 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}
135EXPORT_SYMBOL(unix_detach_fds);
136
137void 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}
151EXPORT_SYMBOL(unix_destruct_scm);