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 user_struct *user; 25 struct file *fp[SCM_MAX_FD]; 26 }; 27 28 struct scm_cookie { 29 struct pid *pid; /* Skb credentials */ 30 struct scm_fp_list *fp; /* Passed files */ 31 struct scm_creds creds; /* Skb credentials */ 32 #ifdef CONFIG_SECURITY_NETWORK 33 u32 secid; /* Passed security ID */ 34 #endif 35 }; 36 37 void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm); 38 void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm); 39 int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm); 40 void __scm_destroy(struct scm_cookie *scm); 41 struct scm_fp_list *scm_fp_dup(struct scm_fp_list *fpl); 42 43 #ifdef CONFIG_SECURITY_NETWORK 44 static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm) 45 { 46 security_socket_getpeersec_dgram(sock, NULL, &scm->secid); 47 } 48 #else 49 static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm) 50 { } 51 #endif /* CONFIG_SECURITY_NETWORK */ 52 53 static __inline__ void scm_set_cred(struct scm_cookie *scm, 54 struct pid *pid, kuid_t uid, kgid_t gid) 55 { 56 scm->pid = get_pid(pid); 57 scm->creds.pid = pid_vnr(pid); 58 scm->creds.uid = uid; 59 scm->creds.gid = gid; 60 } 61 62 static __inline__ void scm_destroy_cred(struct scm_cookie *scm) 63 { 64 put_pid(scm->pid); 65 scm->pid = NULL; 66 } 67 68 static __inline__ void scm_destroy(struct scm_cookie *scm) 69 { 70 scm_destroy_cred(scm); 71 if (scm->fp) 72 __scm_destroy(scm); 73 } 74 75 static __inline__ int scm_send(struct socket *sock, struct msghdr *msg, 76 struct scm_cookie *scm, bool forcecreds) 77 { 78 memset(scm, 0, sizeof(*scm)); 79 scm->creds.uid = INVALID_UID; 80 scm->creds.gid = INVALID_GID; 81 if (forcecreds) 82 scm_set_cred(scm, task_tgid(current), current_uid(), current_gid()); 83 unix_get_peersec_dgram(sock, scm); 84 if (msg->msg_controllen <= 0) 85 return 0; 86 return __scm_send(sock, msg, scm); 87 } 88 89 #ifdef CONFIG_SECURITY_NETWORK 90 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm) 91 { 92 char *secdata; 93 u32 seclen; 94 int err; 95 96 if (test_bit(SOCK_PASSSEC, &sock->flags)) { 97 err = security_secid_to_secctx(scm->secid, &secdata, &seclen); 98 99 if (!err) { 100 put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata); 101 security_release_secctx(secdata, seclen); 102 } 103 } 104 } 105 #else 106 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm) 107 { } 108 #endif /* CONFIG_SECURITY_NETWORK */ 109 110 static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg, 111 struct scm_cookie *scm, int flags) 112 { 113 if (!msg->msg_control) { 114 if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp) 115 msg->msg_flags |= MSG_CTRUNC; 116 scm_destroy(scm); 117 return; 118 } 119 120 if (test_bit(SOCK_PASSCRED, &sock->flags)) { 121 struct user_namespace *current_ns = current_user_ns(); 122 struct ucred ucreds = { 123 .pid = scm->creds.pid, 124 .uid = from_kuid_munged(current_ns, scm->creds.uid), 125 .gid = from_kgid_munged(current_ns, scm->creds.gid), 126 }; 127 put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(ucreds), &ucreds); 128 } 129 130 scm_destroy_cred(scm); 131 132 scm_passec(sock, msg, scm); 133 134 if (!scm->fp) 135 return; 136 137 scm_detach_fds(msg, scm); 138 } 139 140 141 #endif /* __LINUX_NET_SCM_H */ 142 143