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
   8 /* Well, we should have at least one descriptor open
   9  * to accept passed FDs 8)
  10  */
  11 #define SCM_MAX_FD      255
  12
  13 struct scm_fp_list
  14 {
  15         int             count;
  16         struct file     *fp[SCM_MAX_FD];
  17 };
  18
  19 struct scm_cookie
  20 {
  21         struct ucred            creds;          /* Skb credentials      */
  22         struct scm_fp_list      *fp;            /* Passed files         */
  23 #ifdef CONFIG_SECURITY_NETWORK
  24         u32                     secid;          /* Passed security ID   */
  25 #endif
  26         unsigned long           seq;            /* Connection seqno     */
  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 = p->uid;
  56         scm->creds.gid = p->gid;
  57         scm->creds.pid = p->tgid;
  58         scm->fp = NULL;
  59         scm->seq = 0;
  60         unix_get_peersec_dgram(sock, scm);
  61         if (msg->msg_controllen <= 0)
  62                 return 0;
  63         return __scm_send(sock, msg, scm);
  64 }
  65
  66 #ifdef CONFIG_SECURITY_NETWORK
  67 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
  68 {
  69         char *secdata;
  70         u32 seclen;
  71         int err;
  72
  73         if (test_bit(SOCK_PASSSEC, &sock->flags)) {
  74                 err = security_secid_to_secctx(scm->secid, &secdata, &seclen);
  75
  76                 if (!err) {
  77                         put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
  78                         security_release_secctx(secdata, seclen);
  79                 }
  80         }
  81 }
  82 #else
  83 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
  84 { }
  85 #endif /* CONFIG_SECURITY_NETWORK */
  86
  87 static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg,
  88                                 struct scm_cookie *scm, int flags)
  89 {
  90         if (!msg->msg_control)
  91         {
  92                 if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp)
  93                         msg->msg_flags |= MSG_CTRUNC;
  94                 scm_destroy(scm);
  95                 return;
  96         }
  97
  98         if (test_bit(SOCK_PASSCRED, &sock->flags))
  99                 put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(scm->creds), &scm->creds);
 100
 101         scm_passec(sock, msg, scm);
 102
 103         if (!scm->fp)
 104                 return;
 105
 106         scm_detach_fds(msg, scm);
 107 }
 108
 109
 110 #endif /* __LINUX_NET_SCM_H */
 111