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         unsigned long           seq;            /* Connection seqno     */
  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 = p->uid;
  59         scm->creds.gid = p->gid;
  60         scm->creds.pid = task_tgid_vnr(p);
  61         scm->fp = NULL;
  62         scm->seq = 0;
  63         unix_get_peersec_dgram(sock, scm);
  64         if (msg->msg_controllen <= 0)
  65                 return 0;
  66         return __scm_send(sock, msg, scm);
  67 }
  68
  69 #ifdef CONFIG_SECURITY_NETWORK
  70 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
  71 {
  72         char *secdata;
  73         u32 seclen;
  74         int err;
  75
  76         if (test_bit(SOCK_PASSSEC, &sock->flags)) {
  77                 err = security_secid_to_secctx(scm->secid, &secdata, &seclen);
  78
  79                 if (!err) {
  80                         put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
  81                         security_release_secctx(secdata, seclen);
  82                 }
  83         }
  84 }
  85 #else
  86 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
  87 { }
  88 #endif /* CONFIG_SECURITY_NETWORK */
  89
  90 static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg,
  91                                 struct scm_cookie *scm, int flags)
  92 {
  93         if (!msg->msg_control)
  94         {
  95                 if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp)
  96                         msg->msg_flags |= MSG_CTRUNC;
  97                 scm_destroy(scm);
  98                 return;
  99         }
 100
 101         if (test_bit(SOCK_PASSCRED, &sock->flags))
 102                 put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(scm->creds), &scm->creds);
 103
 104         scm_passec(sock, msg, scm);
 105
 106         if (!scm->fp)
 107                 return;
 108
 109         scm_detach_fds(msg, scm);
 110 }
 111
 112
 113 #endif /* __LINUX_NET_SCM_H */
 114