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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
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/security.h>
9#include <linux/pid.h>
10#include <linux/nsproxy.h>
11
12/* Well, we should have at least one descriptor open
13 * to accept passed FDs 8)
14 */
15#define SCM_MAX_FD 253
16
17struct scm_creds {
18 u32 pid;
19 kuid_t uid;
20 kgid_t gid;
21};
22
23struct scm_fp_list {
24 short count;
25 short max;
26 struct user_struct *user;
27 struct file *fp[SCM_MAX_FD];
28};
29
30struct scm_cookie {
31 struct pid *pid; /* Skb credentials */
32 struct scm_fp_list *fp; /* Passed files */
33 struct scm_creds creds; /* Skb credentials */
34#ifdef CONFIG_SECURITY_NETWORK
35 u32 secid; /* Passed security ID */
36#endif
37};
38
39void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm);
40void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm);
41int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm);
42void __scm_destroy(struct scm_cookie *scm);
43struct scm_fp_list *scm_fp_dup(struct scm_fp_list *fpl);
44
45#ifdef CONFIG_SECURITY_NETWORK
46static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
47{
48 security_socket_getpeersec_dgram(sock, NULL, &scm->secid);
49}
50#else
51static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
52{ }
53#endif /* CONFIG_SECURITY_NETWORK */
54
55static __inline__ void scm_set_cred(struct scm_cookie *scm,
56 struct pid *pid, kuid_t uid, kgid_t gid)
57{
58 scm->pid = get_pid(pid);
59 scm->creds.pid = pid_vnr(pid);
60 scm->creds.uid = uid;
61 scm->creds.gid = gid;
62}
63
64static __inline__ void scm_destroy_cred(struct scm_cookie *scm)
65{
66 put_pid(scm->pid);
67 scm->pid = NULL;
68}
69
70static __inline__ void scm_destroy(struct scm_cookie *scm)
71{
72 scm_destroy_cred(scm);
73 if (scm->fp)
74 __scm_destroy(scm);
75}
76
77static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
78 struct scm_cookie *scm, bool forcecreds)
79{
80 memset(scm, 0, sizeof(*scm));
81 scm->creds.uid = INVALID_UID;
82 scm->creds.gid = INVALID_GID;
83 if (forcecreds)
84 scm_set_cred(scm, task_tgid(current), current_uid(), current_gid());
85 unix_get_peersec_dgram(sock, scm);
86 if (msg->msg_controllen <= 0)
87 return 0;
88 return __scm_send(sock, msg, scm);
89}
90
91#ifdef CONFIG_SECURITY_NETWORK
92static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
93{
94 char *secdata;
95 u32 seclen;
96 int err;
97
98 if (test_bit(SOCK_PASSSEC, &sock->flags)) {
99 err = security_secid_to_secctx(scm->secid, &secdata, &seclen);
100
101 if (!err) {
102 put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
103 security_release_secctx(secdata, seclen);
104 }
105 }
106}
107#else
108static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
109{ }
110#endif /* CONFIG_SECURITY_NETWORK */
111
112static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg,
113 struct scm_cookie *scm, int flags)
114{
115 if (!msg->msg_control) {
116 if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp)
117 msg->msg_flags |= MSG_CTRUNC;
118 scm_destroy(scm);
119 return;
120 }
121
122 if (test_bit(SOCK_PASSCRED, &sock->flags)) {
123 struct user_namespace *current_ns = current_user_ns();
124 struct ucred ucreds = {
125 .pid = scm->creds.pid,
126 .uid = from_kuid_munged(current_ns, scm->creds.uid),
127 .gid = from_kgid_munged(current_ns, scm->creds.gid),
128 };
129 put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(ucreds), &ucreds);
130 }
131
132 scm_destroy_cred(scm);
133
134 scm_passec(sock, msg, scm);
135
136 if (!scm->fp)
137 return;
138
139 scm_detach_fds(msg, scm);
140}
141
142
143#endif /* __LINUX_NET_SCM_H */
144