1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __LINUX_NET_SCM_H
3 #define __LINUX_NET_SCM_H
5 #include <linux/limits.h>
7 #include <linux/cred.h>
8 #include <linux/security.h>
10 #include <linux/nsproxy.h>
11 #include <linux/sched/signal.h>
13 /* Well, we should have at least one descriptor open
14 * to accept passed FDs 8)
16 #define SCM_MAX_FD 253
27 struct user_struct *user;
28 struct file *fp[SCM_MAX_FD];
32 struct pid *pid; /* Skb credentials */
33 struct scm_fp_list *fp; /* Passed files */
34 struct scm_creds creds; /* Skb credentials */
35 #ifdef CONFIG_SECURITY_NETWORK
36 u32 secid; /* Passed security ID */
40 int __scm_install_fd(struct file *file, int __user *ufd, unsigned int o_flags);
41 void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm);
42 void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm);
43 int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm);
44 void __scm_destroy(struct scm_cookie *scm);
45 struct scm_fp_list *scm_fp_dup(struct scm_fp_list *fpl);
47 #ifdef CONFIG_SECURITY_NETWORK
48 static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
50 security_socket_getpeersec_dgram(sock, NULL, &scm->secid);
53 static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
55 #endif /* CONFIG_SECURITY_NETWORK */
57 static __inline__ void scm_set_cred(struct scm_cookie *scm,
58 struct pid *pid, kuid_t uid, kgid_t gid)
60 scm->pid = get_pid(pid);
61 scm->creds.pid = pid_vnr(pid);
66 static __inline__ void scm_destroy_cred(struct scm_cookie *scm)
72 static __inline__ void scm_destroy(struct scm_cookie *scm)
74 scm_destroy_cred(scm);
79 static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
80 struct scm_cookie *scm, bool forcecreds)
82 memset(scm, 0, sizeof(*scm));
83 scm->creds.uid = INVALID_UID;
84 scm->creds.gid = INVALID_GID;
86 scm_set_cred(scm, task_tgid(current), current_uid(), current_gid());
87 unix_get_peersec_dgram(sock, scm);
88 if (msg->msg_controllen <= 0)
90 return __scm_send(sock, msg, scm);
93 #ifdef CONFIG_SECURITY_NETWORK
94 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
100 if (test_bit(SOCK_PASSSEC, &sock->flags)) {
101 err = security_secid_to_secctx(scm->secid, &secdata, &seclen);
104 put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
105 security_release_secctx(secdata, seclen);
110 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
112 #endif /* CONFIG_SECURITY_NETWORK */
114 static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg,
115 struct scm_cookie *scm, int flags)
117 if (!msg->msg_control) {
118 if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp)
119 msg->msg_flags |= MSG_CTRUNC;
124 if (test_bit(SOCK_PASSCRED, &sock->flags)) {
125 struct user_namespace *current_ns = current_user_ns();
126 struct ucred ucreds = {
127 .pid = scm->creds.pid,
128 .uid = from_kuid_munged(current_ns, scm->creds.uid),
129 .gid = from_kgid_munged(current_ns, scm->creds.gid),
131 put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(ucreds), &ucreds);
134 scm_destroy_cred(scm);
136 scm_passec(sock, msg, scm);
141 scm_detach_fds(msg, scm);
145 #endif /* __LINUX_NET_SCM_H */