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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __LINUX_NET_SCM_H
3#define __LINUX_NET_SCM_H
4
5#include <linux/limits.h>
6#include <linux/net.h>
7#include <linux/cred.h>
8#include <linux/file.h>
9#include <linux/security.h>
10#include <linux/pid.h>
11#include <linux/nsproxy.h>
12#include <linux/sched/signal.h>
13#include <net/compat.h>
14
15/* Well, we should have at least one descriptor open
16 * to accept passed FDs 8)
17 */
18#define SCM_MAX_FD 253
19
20struct scm_creds {
21 u32 pid;
22 kuid_t uid;
23 kgid_t gid;
24};
25
26#ifdef CONFIG_UNIX
27struct unix_edge;
28#endif
29
30struct scm_fp_list {
31 short count;
32 short count_unix;
33 short max;
34#ifdef CONFIG_UNIX
35 bool inflight;
36 bool dead;
37 struct list_head vertices;
38 struct unix_edge *edges;
39#endif
40 struct user_struct *user;
41 struct file *fp[SCM_MAX_FD];
42};
43
44struct scm_cookie {
45 struct pid *pid; /* Skb credentials */
46 struct scm_fp_list *fp; /* Passed files */
47 struct scm_creds creds; /* Skb credentials */
48#ifdef CONFIG_SECURITY_NETWORK
49 u32 secid; /* Passed security ID */
50#endif
51};
52
53void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm);
54void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm);
55int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm);
56void __scm_destroy(struct scm_cookie *scm);
57struct scm_fp_list *scm_fp_dup(struct scm_fp_list *fpl);
58
59#ifdef CONFIG_SECURITY_NETWORK
60static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
61{
62 security_socket_getpeersec_dgram(sock, NULL, secid: &scm->secid);
63}
64#else
65static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
66{ }
67#endif /* CONFIG_SECURITY_NETWORK */
68
69static __inline__ void scm_set_cred(struct scm_cookie *scm,
70 struct pid *pid, kuid_t uid, kgid_t gid)
71{
72 scm->pid = get_pid(pid);
73 scm->creds.pid = pid_vnr(pid);
74 scm->creds.uid = uid;
75 scm->creds.gid = gid;
76}
77
78static __inline__ void scm_destroy_cred(struct scm_cookie *scm)
79{
80 put_pid(pid: scm->pid);
81 scm->pid = NULL;
82}
83
84static __inline__ void scm_destroy(struct scm_cookie *scm)
85{
86 scm_destroy_cred(scm);
87 if (scm->fp)
88 __scm_destroy(scm);
89}
90
91static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
92 struct scm_cookie *scm, bool forcecreds)
93{
94 memset(scm, 0, sizeof(*scm));
95 scm->creds.uid = INVALID_UID;
96 scm->creds.gid = INVALID_GID;
97 if (forcecreds)
98 scm_set_cred(scm, pid: task_tgid(current), current_uid(), current_gid());
99 unix_get_peersec_dgram(sock, scm);
100 if (msg->msg_controllen <= 0)
101 return 0;
102 return __scm_send(sock, msg, scm);
103}
104
105void scm_recv(struct socket *sock, struct msghdr *msg,
106 struct scm_cookie *scm, int flags);
107void scm_recv_unix(struct socket *sock, struct msghdr *msg,
108 struct scm_cookie *scm, int flags);
109
110static inline int scm_recv_one_fd(struct file *f, int __user *ufd,
111 unsigned int flags)
112{
113 if (!ufd)
114 return -EFAULT;
115 return receive_fd(file: f, ufd, o_flags: flags);
116}
117
118#endif /* __LINUX_NET_SCM_H */
119
120

source code of linux/include/net/scm.h