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      253
  14
  15 struct scm_fp_list
  16 {
  17         struct list_head        list;
  18         short                   count;
  19         short                   max;
  20         struct file             *fp[SCM_MAX_FD];
  21 };
  22
  23 struct scm_cookie
  24 {
  25         struct ucred            creds;          /* Skb credentials      */
  26         struct scm_fp_list      *fp;            /* Passed files         */
  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
  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
  44 static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
  45 { }
  46 #endif /* CONFIG_SECURITY_NETWORK */
  47
  48 static __inline__ void scm_destroy(struct scm_cookie *scm)
  49 {
  50         if (scm && scm->fp)
  51                 __scm_destroy(scm);
  52 }
  53
  54 static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
  55                                struct scm_cookie *scm)
  56 {
  57         struct task_struct *p = current;
  58         scm->creds.uid = current_uid();
  59         scm->creds.gid = current_gid();
  60         scm->creds.pid = task_tgid_vnr(p);
  61         scm->fp = NULL;
  62         unix_get_peersec_dgram(sock, scm);
  63         if (msg->msg_controllen <= 0)
  64                 return 0;
  65         return __scm_send(sock, msg, scm);
  66 }
  67
  68 #ifdef CONFIG_SECURITY_NETWORK
  69 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
  70 {
  71         char *secdata;
  72         u32 seclen;
  73         int err;
  74
  75         if (test_bit(SOCK_PASSSEC, &sock->flags)) {
  76                 err = security_secid_to_secctx(scm->secid, &secdata, &seclen);
  77
  78                 if (!err) {
  79                         put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
  80                         security_release_secctx(secdata, seclen);
  81                 }
  82         }
  83 }
  84 #else
  85 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
  86 { }
  87 #endif /* CONFIG_SECURITY_NETWORK */
  88
  89 static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg,
  90                                 struct scm_cookie *scm, int flags)
  91 {
  92         if (!msg->msg_control)
  93         {
  94                 if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp)
  95                         msg->msg_flags |= MSG_CTRUNC;
  96                 scm_destroy(scm);
  97                 return;
  98         }
  99
 100         if (test_bit(SOCK_PASSCRED, &sock->flags))
 101                 put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(scm->creds), &scm->creds);
 102
 103         scm_passec(sock, msg, scm);
 104
 105         if (!scm->fp)
 106                 return;
 107
 108         scm_detach_fds(msg, scm);
 109 }
 110
 111
 112 #endif /* __LINUX_NET_SCM_H */
 113