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_set_cred_noref(struct scm_cookie *scm,
  57                                     struct pid *pid, const struct cred *cred)
  58 {
  59         scm->pid  = pid;
  60         scm->cred = cred;
  61         cred_to_ucred(pid, cred, &scm->creds);
  62 }
  63
  64 static __inline__ void scm_destroy_cred(struct scm_cookie *scm)
  65 {
  66         put_pid(scm->pid);
  67         scm->pid  = NULL;
  68
  69         if (scm->cred)
  70                 put_cred(scm->cred);
  71         scm->cred = NULL;
  72 }
  73
  74 static __inline__ void scm_destroy(struct scm_cookie *scm)
  75 {
  76         scm_destroy_cred(scm);
  77         if (scm && scm->fp)
  78                 __scm_destroy(scm);
  79 }
  80
  81 static __inline__ void scm_release(struct scm_cookie *scm)
  82 {
  83         /* keep ref on pid and cred */
  84         scm->pid = NULL;
  85         scm->cred = NULL;
  86         if (scm->fp)
  87                 __scm_destroy(scm);
  88 }
  89
  90 static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
  91                                struct scm_cookie *scm)
  92 {
  93         scm_set_cred(scm, task_tgid(current), current_cred());
  94         scm->fp = NULL;
  95         unix_get_peersec_dgram(sock, scm);
  96         if (msg->msg_controllen <= 0)
  97                 return 0;
  98         return __scm_send(sock, msg, scm);
  99 }
 100
 101 #ifdef CONFIG_SECURITY_NETWORK
 102 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
 103 {
 104         char *secdata;
 105         u32 seclen;
 106         int err;
 107
 108         if (test_bit(SOCK_PASSSEC, &sock->flags)) {
 109                 err = security_secid_to_secctx(scm->secid, &secdata, &seclen);
 110
 111                 if (!err) {
 112                         put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
 113                         security_release_secctx(secdata, seclen);
 114                 }
 115         }
 116 }
 117 #else
 118 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
 119 { }
 120 #endif /* CONFIG_SECURITY_NETWORK */
 121
 122 static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg,
 123                                 struct scm_cookie *scm, int flags)
 124 {
 125         if (!msg->msg_control) {
 126                 if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp)
 127                         msg->msg_flags |= MSG_CTRUNC;
 128                 if (scm && scm->fp)
 129                         __scm_destroy(scm);
 130                 return;
 131         }
 132
 133         if (test_bit(SOCK_PASSCRED, &sock->flags))
 134                 put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(scm->creds), &scm->creds);
 135
 136         scm_passec(sock, msg, scm);
 137
 138         if (!scm->fp)
 139                 return;
 140
 141         scm_detach_fds(msg, scm);
 142 }
 143
 144
 145 #endif /* __LINUX_NET_SCM_H */
 146