aboutsummaryrefslogtreecommitdiff
path: root/include/net/scm.h
blob: 975cca01048bee3b7da9017725654053921250ae (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
#ifndef __LINUX_NET_SCM_H
#define __LINUX_NET_SCM_H

#include <linux/limits.h>
#include <linux/net.h>
#include <linux/security.h>
#include <linux/pid.h>
#include <linux/nsproxy.h>

/* Well, we should have at least one descriptor open
 * to accept passed FDs 8)
 */
#define SCM_MAX_FD	253

struct scm_creds {
	u32	pid;
	kuid_t	uid;
	kgid_t	gid;
};

struct scm_fp_list {
	short			count;
	short			max;
	struct file		*fp[SCM_MAX_FD];
};

struct scm_cookie {
	struct pid		*pid;		/* Skb credentials */
	const struct cred	*cred;
	struct scm_fp_list	*fp;		/* Passed files		*/
	struct scm_creds	creds;		/* Skb credentials	*/
#ifdef CONFIG_SECURITY_NETWORK
	u32			secid;		/* Passed security ID 	*/
#endif
};

extern void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm);
extern void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm);
extern int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm);
extern void __scm_destroy(struct scm_cookie *scm);
extern struct scm_fp_list * scm_fp_dup(struct scm_fp_list *fpl);

#ifdef CONFIG_SECURITY_NETWORK
static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
{
	security_socket_getpeersec_dgram(sock, NULL, &scm->secid);
}
#else
static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
{ }
#endif /* CONFIG_SECURITY_NETWORK */

static __inline__ void scm_set_cred(struct scm_cookie *scm,
				    struct pid *pid, const struct cred *cred)
{
	scm->pid  = get_pid(pid);
	scm->cred = cred ? get_cred(cred) : NULL;
	scm->creds.pid = pid_vnr(pid);
	scm->creds.uid = cred ? cred->euid : INVALID_UID;
	scm->creds.gid = cred ? cred->egid : INVALID_GID;
}

static __inline__ void scm_destroy_cred(struct scm_cookie *scm)
{
	put_pid(scm->pid);
	scm->pid  = NULL;

	if (scm->cred)
		put_cred(scm->cred);
	scm->cred = NULL;
}

static __inline__ void scm_destroy(struct scm_cookie *scm)
{
	scm_destroy_cred(scm);
	if (scm->fp)
		__scm_destroy(scm);
}

static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
			       struct scm_cookie *scm, bool forcecreds)
{
	memset(scm, 0, sizeof(*scm));
	if (forcecreds)
		scm_set_cred(scm, task_tgid(current), current_cred());
	unix_get_peersec_dgram(sock, scm);
	if (msg->msg_controllen <= 0)
		return 0;
	return __scm_send(sock, msg, scm);
}

#ifdef CONFIG_SECURITY_NETWORK
static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
{
	char *secdata;
	u32 seclen;
	int err;

	if (test_bit(SOCK_PASSSEC, &sock->flags)) {
		err = security_secid_to_secctx(scm->secid, &secdata, &seclen);

		if (!err) {
			put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
			security_release_secctx(secdata, seclen);
		}
	}
}
#else
static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
{ }
#endif /* CONFIG_SECURITY_NETWORK */

static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg,
				struct scm_cookie *scm, int flags)
{
	if (!msg->msg_control) {
		if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp)
			msg->msg_flags |= MSG_CTRUNC;
		scm_destroy(scm);
		return;
	}

	if (test_bit(SOCK_PASSCRED, &sock->flags)) {
		struct user_namespace *current_ns = current_user_ns();
		struct ucred ucreds = {
			.pid = scm->creds.pid,
			.uid = from_kuid_munged(current_ns, scm->creds.uid),
			.gid = from_kgid_munged(current_ns, scm->creds.gid),
		};
		put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(ucreds), &ucreds);
	}

	scm_destroy_cred(scm);

	scm_passec(sock, msg, scm);

	if (!scm->fp)
		return;
	
	scm_detach_fds(msg, scm);
}


#endif /* __LINUX_NET_SCM_H */