xref: /linux/include/net/scm.h (revision 14b42963f64b98ab61fa9723c03d71aa5ef4f862)
1 #ifndef __LINUX_NET_SCM_H
2 #define __LINUX_NET_SCM_H
3 
4 #include <linux/limits.h>
5 #include <linux/net.h>
6 
7 /* Well, we should have at least one descriptor open
8  * to accept passed FDs 8)
9  */
10 #define SCM_MAX_FD	(OPEN_MAX-1)
11 
12 struct scm_fp_list
13 {
14 	int		count;
15 	struct file	*fp[SCM_MAX_FD];
16 };
17 
18 struct scm_cookie
19 {
20 	struct ucred		creds;		/* Skb credentials	*/
21 	struct scm_fp_list	*fp;		/* Passed files		*/
22 #ifdef CONFIG_SECURITY_NETWORK
23 	char			*secdata;	/* Security context	*/
24 	u32			seclen;		/* Security length	*/
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 static __inline__ void scm_destroy(struct scm_cookie *scm)
36 {
37 	if (scm && scm->fp)
38 		__scm_destroy(scm);
39 }
40 
41 static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
42 			       struct scm_cookie *scm)
43 {
44 	struct task_struct *p = current;
45 	scm->creds.uid = p->uid;
46 	scm->creds.gid = p->gid;
47 	scm->creds.pid = p->tgid;
48 	scm->fp = NULL;
49 	scm->seq = 0;
50 	if (msg->msg_controllen <= 0)
51 		return 0;
52 	return __scm_send(sock, msg, scm);
53 }
54 
55 #ifdef CONFIG_SECURITY_NETWORK
56 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
57 {
58 	if (test_bit(SOCK_PASSSEC, &sock->flags) && scm->secdata != NULL)
59 		put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, scm->seclen, scm->secdata);
60 }
61 #else
62 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
63 { }
64 #endif /* CONFIG_SECURITY_NETWORK */
65 
66 static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg,
67 				struct scm_cookie *scm, int flags)
68 {
69 	if (!msg->msg_control)
70 	{
71 		if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp)
72 			msg->msg_flags |= MSG_CTRUNC;
73 		scm_destroy(scm);
74 		return;
75 	}
76 
77 	if (test_bit(SOCK_PASSCRED, &sock->flags))
78 		put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(scm->creds), &scm->creds);
79 
80 	scm_passec(sock, msg, scm);
81 
82 	if (!scm->fp)
83 		return;
84 
85 	scm_detach_fds(msg, scm);
86 }
87 
88 
89 #endif /* __LINUX_NET_SCM_H */
90 
91