xref: /openbmc/linux/include/net/scm.h (revision e868d61272caa648214046a096e5a6bfc068dc8c)
1 #ifndef __LINUX_NET_SCM_H
2 #define __LINUX_NET_SCM_H
3 
4 #include <linux/limits.h>
5 #include <linux/net.h>
6 #include <linux/security.h>
7 
8 /* Well, we should have at least one descriptor open
9  * to accept passed FDs 8)
10  */
11 #define SCM_MAX_FD	(OPEN_MAX-1)
12 
13 struct scm_fp_list
14 {
15 	int		count;
16 	struct file	*fp[SCM_MAX_FD];
17 };
18 
19 struct scm_cookie
20 {
21 	struct ucred		creds;		/* Skb credentials	*/
22 	struct scm_fp_list	*fp;		/* Passed files		*/
23 #ifdef CONFIG_SECURITY_NETWORK
24 	u32			secid;		/* Passed security ID 	*/
25 #endif
26 	unsigned long		seq;		/* Connection seqno	*/
27 };
28 
29 extern void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm);
30 extern void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm);
31 extern int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm);
32 extern void __scm_destroy(struct scm_cookie *scm);
33 extern struct scm_fp_list * scm_fp_dup(struct scm_fp_list *fpl);
34 
35 #ifdef CONFIG_SECURITY_NETWORK
36 static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
37 {
38 	security_socket_getpeersec_dgram(sock, NULL, &scm->secid);
39 }
40 #else
41 static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
42 { }
43 #endif /* CONFIG_SECURITY_NETWORK */
44 
45 static __inline__ void scm_destroy(struct scm_cookie *scm)
46 {
47 	if (scm && scm->fp)
48 		__scm_destroy(scm);
49 }
50 
51 static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
52 			       struct scm_cookie *scm)
53 {
54 	struct task_struct *p = current;
55 	scm->creds.uid = p->uid;
56 	scm->creds.gid = p->gid;
57 	scm->creds.pid = p->tgid;
58 	scm->fp = NULL;
59 	scm->seq = 0;
60 	unix_get_peersec_dgram(sock, scm);
61 	if (msg->msg_controllen <= 0)
62 		return 0;
63 	return __scm_send(sock, msg, scm);
64 }
65 
66 #ifdef CONFIG_SECURITY_NETWORK
67 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
68 {
69 	char *secdata;
70 	u32 seclen;
71 	int err;
72 
73 	if (test_bit(SOCK_PASSSEC, &sock->flags)) {
74 		err = security_secid_to_secctx(scm->secid, &secdata, &seclen);
75 
76 		if (!err) {
77 			put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
78 			security_release_secctx(secdata, seclen);
79 		}
80 	}
81 }
82 #else
83 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
84 { }
85 #endif /* CONFIG_SECURITY_NETWORK */
86 
87 static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg,
88 				struct scm_cookie *scm, int flags)
89 {
90 	if (!msg->msg_control)
91 	{
92 		if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp)
93 			msg->msg_flags |= MSG_CTRUNC;
94 		scm_destroy(scm);
95 		return;
96 	}
97 
98 	if (test_bit(SOCK_PASSCRED, &sock->flags))
99 		put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(scm->creds), &scm->creds);
100 
101 	scm_passec(sock, msg, scm);
102 
103 	if (!scm->fp)
104 		return;
105 
106 	scm_detach_fds(msg, scm);
107 }
108 
109 
110 #endif /* __LINUX_NET_SCM_H */
111 
112