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_creds { 16 u32 pid; 17 kuid_t uid; 18 kgid_t gid; 19 }; 20 21 struct scm_fp_list { 22 short count; 23 short max; 24 struct file *fp[SCM_MAX_FD]; 25 }; 26 27 struct scm_cookie { 28 struct pid *pid; /* Skb credentials */ 29 struct scm_fp_list *fp; /* Passed files */ 30 struct scm_creds creds; /* Skb credentials */ 31 #ifdef CONFIG_SECURITY_NETWORK 32 u32 secid; /* Passed security ID */ 33 #endif 34 }; 35 36 void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm); 37 void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm); 38 int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm); 39 void __scm_destroy(struct scm_cookie *scm); 40 struct scm_fp_list *scm_fp_dup(struct scm_fp_list *fpl); 41 42 #ifdef CONFIG_SECURITY_NETWORK 43 static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm) 44 { 45 security_socket_getpeersec_dgram(sock, NULL, &scm->secid); 46 } 47 #else 48 static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm) 49 { } 50 #endif /* CONFIG_SECURITY_NETWORK */ 51 52 static __inline__ void scm_set_cred(struct scm_cookie *scm, 53 struct pid *pid, kuid_t uid, kgid_t gid) 54 { 55 scm->pid = get_pid(pid); 56 scm->creds.pid = pid_vnr(pid); 57 scm->creds.uid = uid; 58 scm->creds.gid = gid; 59 } 60 61 static __inline__ void scm_destroy_cred(struct scm_cookie *scm) 62 { 63 put_pid(scm->pid); 64 scm->pid = NULL; 65 } 66 67 static __inline__ void scm_destroy(struct scm_cookie *scm) 68 { 69 scm_destroy_cred(scm); 70 if (scm->fp) 71 __scm_destroy(scm); 72 } 73 74 static __inline__ int scm_send(struct socket *sock, struct msghdr *msg, 75 struct scm_cookie *scm, bool forcecreds) 76 { 77 memset(scm, 0, sizeof(*scm)); 78 scm->creds.uid = INVALID_UID; 79 scm->creds.gid = INVALID_GID; 80 if (forcecreds) 81 scm_set_cred(scm, task_tgid(current), current_uid(), current_gid()); 82 unix_get_peersec_dgram(sock, scm); 83 if (msg->msg_controllen <= 0) 84 return 0; 85 return __scm_send(sock, msg, scm); 86 } 87 88 #ifdef CONFIG_SECURITY_NETWORK 89 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm) 90 { 91 char *secdata; 92 u32 seclen; 93 int err; 94 95 if (test_bit(SOCK_PASSSEC, &sock->flags)) { 96 err = security_secid_to_secctx(scm->secid, &secdata, &seclen); 97 98 if (!err) { 99 put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata); 100 security_release_secctx(secdata, seclen); 101 } 102 } 103 } 104 #else 105 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm) 106 { } 107 #endif /* CONFIG_SECURITY_NETWORK */ 108 109 static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg, 110 struct scm_cookie *scm, int flags) 111 { 112 if (!msg->msg_control) { 113 if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp) 114 msg->msg_flags |= MSG_CTRUNC; 115 scm_destroy(scm); 116 return; 117 } 118 119 if (test_bit(SOCK_PASSCRED, &sock->flags)) { 120 struct user_namespace *current_ns = current_user_ns(); 121 struct ucred ucreds = { 122 .pid = scm->creds.pid, 123 .uid = from_kuid_munged(current_ns, scm->creds.uid), 124 .gid = from_kgid_munged(current_ns, scm->creds.gid), 125 }; 126 put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(ucreds), &ucreds); 127 } 128 129 scm_destroy_cred(scm); 130 131 scm_passec(sock, msg, scm); 132 133 if (!scm->fp) 134 return; 135 136 scm_detach_fds(msg, scm); 137 } 138 139 140 #endif /* __LINUX_NET_SCM_H */ 141 142