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         struct list_head        list;
  17         short                   count;
  18         short                   max;
  19         struct file             *fp[SCM_MAX_FD];
  20 };
  21
  22 struct scm_cookie {
  23         struct pid              *pid;           /* Skb credentials */
  24         const struct cred       *cred;
  25         struct scm_fp_list      *fp;            /* Passed files         */
  26         struct ucred            creds;          /* Skb credentials      */
  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_set_cred(struct scm_cookie *scm,
  49                                     struct pid *pid, const struct cred *cred)
  50 {
  51         scm->pid  = get_pid(pid);
  52         scm->cred = get_cred(cred);
  53         cred_to_ucred(pid, cred, &scm->creds);
  54 }
  55
  56 static __inline__ void scm_destroy_cred(struct scm_cookie *scm)
  57 {
  58         put_pid(scm->pid);
  59         scm->pid  = NULL;
  60
  61         if (scm->cred)
  62                 put_cred(scm->cred);
  63         scm->cred = NULL;
  64 }
  65
  66 static __inline__ void scm_destroy(struct scm_cookie *scm)
  67 {
  68         scm_destroy_cred(scm);
  69         if (scm && scm->fp)
  70                 __scm_destroy(scm);
  71 }
  72
  73 static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
  74                                struct scm_cookie *scm)
  75 {
  76         scm_set_cred(scm, task_tgid(current), current_cred());
  77         scm->fp = NULL;
  78         unix_get_peersec_dgram(sock, scm);
  79         if (msg->msg_controllen <= 0)
  80                 return 0;
  81         return __scm_send(sock, msg, scm);
  82 }
  83
  84 #ifdef CONFIG_SECURITY_NETWORK
  85 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
  86 {
  87         char *secdata;
  88         u32 seclen;
  89         int err;
  90
  91         if (test_bit(SOCK_PASSSEC, &sock->flags)) {
  92                 err = security_secid_to_secctx(scm->secid, &secdata, &seclen);
  93
  94                 if (!err) {
  95                         put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
  96                         security_release_secctx(secdata, seclen);
  97                 }
  98         }
  99 }
 100 #else
 101 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
 102 { }
 103 #endif /* CONFIG_SECURITY_NETWORK */
 104
 105 static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg,
 106                                 struct scm_cookie *scm, int flags)
 107 {
 108         if (!msg->msg_control) {
 109                 if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp)
 110                         msg->msg_flags |= MSG_CTRUNC;
 111                 scm_destroy(scm);
 112                 return;
 113         }
 114
 115         if (test_bit(SOCK_PASSCRED, &sock->flags))
 116                 put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(scm->creds), &scm->creds);
 117
 118         scm_destroy_cred(scm);
 119
 120         scm_passec(sock, msg, scm);
 121
 122         if (!scm->fp)
 123                 return;
 124
 125         scm_detach_fds(msg, scm);
 126 }
 127
 128
 129 #endif /* __LINUX_NET_SCM_H */
 130