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 const struct cred *cred; 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 extern void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm); 38 extern void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm); 39 extern int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm); 40 extern void __scm_destroy(struct scm_cookie *scm); 41 extern 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, const struct cred *cred) 55 { 56 scm->pid = get_pid(pid); 57 scm->cred = cred ? get_cred(cred) : NULL; 58 scm->creds.pid = pid_vnr(pid); 59 scm->creds.uid = cred ? cred->euid : INVALID_UID; 60 scm->creds.gid = cred ? cred->egid : INVALID_GID; 61 } 62 63 static __inline__ void scm_destroy_cred(struct scm_cookie *scm) 64 { 65 put_pid(scm->pid); 66 scm->pid = NULL; 67 68 if (scm->cred) 69 put_cred(scm->cred); 70 scm->cred = NULL; 71 } 72 73 static __inline__ void scm_destroy(struct scm_cookie *scm) 74 { 75 scm_destroy_cred(scm); 76 if (scm->fp) 77 __scm_destroy(scm); 78 } 79 80 static __inline__ int scm_send(struct socket *sock, struct msghdr *msg, 81 struct scm_cookie *scm, bool forcecreds) 82 { 83 memset(scm, 0, sizeof(*scm)); 84 if (forcecreds) 85 scm_set_cred(scm, task_tgid(current), current_cred()); 86 unix_get_peersec_dgram(sock, scm); 87 if (msg->msg_controllen <= 0) 88 return 0; 89 return __scm_send(sock, msg, scm); 90 } 91 92 #ifdef CONFIG_SECURITY_NETWORK 93 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm) 94 { 95 char *secdata; 96 u32 seclen; 97 int err; 98 99 if (test_bit(SOCK_PASSSEC, &sock->flags)) { 100 err = security_secid_to_secctx(scm->secid, &secdata, &seclen); 101 102 if (!err) { 103 put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata); 104 security_release_secctx(secdata, seclen); 105 } 106 } 107 } 108 #else 109 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm) 110 { } 111 #endif /* CONFIG_SECURITY_NETWORK */ 112 113 static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg, 114 struct scm_cookie *scm, int flags) 115 { 116 if (!msg->msg_control) { 117 if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp) 118 msg->msg_flags |= MSG_CTRUNC; 119 scm_destroy(scm); 120 return; 121 } 122 123 if (test_bit(SOCK_PASSCRED, &sock->flags)) { 124 struct user_namespace *current_ns = current_user_ns(); 125 struct ucred ucreds = { 126 .pid = scm->creds.pid, 127 .uid = from_kuid_munged(current_ns, scm->creds.uid), 128 .gid = from_kgid_munged(current_ns, scm->creds.gid), 129 }; 130 put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(ucreds), &ucreds); 131 } 132 133 scm_destroy_cred(scm); 134 135 scm_passec(sock, msg, scm); 136 137 if (!scm->fp) 138 return; 139 140 scm_detach_fds(msg, scm); 141 } 142 143 144 #endif /* __LINUX_NET_SCM_H */ 145 146