include/net/scm.h

   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      255
  14
  15 struct scm_fp_list {
  16         struct list_head        list;
  17         int                     count;
  18         struct file             *fp[SCM_MAX_FD];
  19 };
  20
  21 struct scm_cookie {
  22         struct scm_fp_list      *fp;            /* Passed files         */
  23         struct ucred            creds;          /* Skb credentials      */
  24 #ifdef CONFIG_SECURITY_NETWORK
  25         u32                     secid;          /* Passed security ID   */
  26 #endif
  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 = current_uid();
  56         scm->creds.gid = current_gid();
  57         scm->creds.pid = task_tgid_vnr(p);
  58         scm->fp = NULL;
  59         unix_get_peersec_dgram(sock, scm);
  60         if (msg->msg_controllen <= 0)
  61                 return 0;
  62         return __scm_send(sock, msg, scm);
  63 }
  64
  65 #ifdef CONFIG_SECURITY_NETWORK
  66 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
  67 {
  68         char *secdata;
  69         u32 seclen;
  70         int err;
  71
  72         if (test_bit(SOCK_PASSSEC, &sock->flags)) {
  73                 err = security_secid_to_secctx(scm->secid, &secdata, &seclen);
  74
  75                 if (!err) {
  76                         put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
  77                         security_release_secctx(secdata, seclen);
  78                 }
  79         }
  80 }
  81 #else
  82 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
  83 { }
  84 #endif /* CONFIG_SECURITY_NETWORK */
  85
  86 static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg,
  87                                 struct scm_cookie *scm, int flags)
  88 {
  89         if (!msg->msg_control) {
  90                 if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp)
  91                         msg->msg_flags |= MSG_CTRUNC;
  92                 scm_destroy(scm);
  93                 return;
  94         }
  95
  96         if (test_bit(SOCK_PASSCRED, &sock->flags))
  97                 put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(scm->creds), &scm->creds);
  98
  99         scm_passec(sock, msg, scm);
 100
 101         if (!scm->fp)
 102                 return;
 103
 104         scm_detach_fds(msg, scm);
 105 }
 106
 107
 108 #endif /* __LINUX_NET_SCM_H */
 109