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