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         short                   count;
  17         short                   max;
  18         struct file             *fp[SCM_MAX_FD];
  19 };
  20
  21 struct scm_cookie {
  22         struct pid              *pid;           /* Skb credentials */
  23         const struct cred       *cred;
  24         struct scm_fp_list      *fp;            /* Passed files         */
  25         struct ucred            creds;          /* Skb credentials      */
  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_set_cred(struct scm_cookie *scm,
  48                                     struct pid *pid, const struct cred *cred)
  49 {
  50         scm->pid  = get_pid(pid);
  51         scm->cred = cred ? get_cred(cred) : NULL;
  52         cred_to_ucred(pid, cred, &scm->creds);
  53 }
  54
  55 static __inline__ void scm_destroy_cred(struct scm_cookie *scm)
  56 {
  57         put_pid(scm->pid);
  58         scm->pid  = NULL;
  59
  60         if (scm->cred)
  61                 put_cred(scm->cred);
  62         scm->cred = NULL;
  63 }
  64
  65 static __inline__ void scm_destroy(struct scm_cookie *scm)
  66 {
  67         scm_destroy_cred(scm);
  68         if (scm && scm->fp)
  69                 __scm_destroy(scm);
  70 }
  71
  72 static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
  73                                struct scm_cookie *scm, bool forcecreds)
  74 {
  75         memset(scm, 0, sizeof(*scm));
  76         if (forcecreds)
  77                 scm_set_cred(scm, task_tgid(current), current_cred());
  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