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 {
  17         struct list_head        list;
  18         int                     count;
  19         struct file             *fp[SCM_MAX_FD];
  20 };
  21
  22 struct scm_cookie
  23 {
  24         struct ucred            creds;          /* Skb credentials      */
  25         struct scm_fp_list      *fp;            /* Passed files         */
  26 #ifdef CONFIG_SECURITY_NETWORK
  27         u32                     secid;          /* Passed security ID   */
  28 #endif
  29 };
  30
  31 extern void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm);
  32 extern void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm);
  33 extern int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm);
  34 extern void __scm_destroy(struct scm_cookie *scm);
  35 extern struct scm_fp_list * scm_fp_dup(struct scm_fp_list *fpl);
  36
  37 #ifdef CONFIG_SECURITY_NETWORK
  38 static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
  39 {
  40         security_socket_getpeersec_dgram(sock, NULL, &scm->secid);
  41 }
  42 #else
  43 static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
  44 { }
  45 #endif /* CONFIG_SECURITY_NETWORK */
  46
  47 static __inline__ void scm_destroy(struct scm_cookie *scm)
  48 {
  49         if (scm && scm->fp)
  50                 __scm_destroy(scm);
  51 }
  52
  53 static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
  54                                struct scm_cookie *scm)
  55 {
  56         struct task_struct *p = current;
  57         scm->creds.uid = current_uid();
  58         scm->creds.gid = current_gid();
  59         scm->creds.pid = task_tgid_vnr(p);
  60         scm->fp = NULL;
  61         unix_get_peersec_dgram(sock, scm);
  62         if (msg->msg_controllen <= 0)
  63                 return 0;
  64         return __scm_send(sock, msg, scm);
  65 }
  66
  67 #ifdef CONFIG_SECURITY_NETWORK
  68 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
  69 {
  70         char *secdata;
  71         u32 seclen;
  72         int err;
  73
  74         if (test_bit(SOCK_PASSSEC, &sock->flags)) {
  75                 err = security_secid_to_secctx(scm->secid, &secdata, &seclen);
  76
  77                 if (!err) {
  78                         put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
  79                         security_release_secctx(secdata, seclen);
  80                 }
  81         }
  82 }
  83 #else
  84 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
  85 { }
  86 #endif /* CONFIG_SECURITY_NETWORK */
  87
  88 static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg,
  89                                 struct scm_cookie *scm, int flags)
  90 {
  91         if (!msg->msg_control)
  92         {
  93                 if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp)
  94                         msg->msg_flags |= MSG_CTRUNC;
  95                 scm_destroy(scm);
  96                 return;
  97         }
  98
  99         if (test_bit(SOCK_PASSCRED, &sock->flags))
 100                 put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(scm->creds), &scm->creds);
 101
 102         scm_passec(sock, msg, scm);
 103
 104         if (!scm->fp)
 105                 return;
 106
 107         scm_detach_fds(msg, scm);
 108 }
 109
 110
 111 #endif /* __LINUX_NET_SCM_H */
 112