Index: sys/compat/linux/linux_socket.h
===================================================================
--- sys/compat/linux/linux_socket.h
+++ sys/compat/linux/linux_socket.h
@@ -195,6 +195,7 @@
 #endif
 #define	LINUX_SO_TIMESTAMP	29
 #define	LINUX_SO_ACCEPTCONN	30
+#define	LINUX_SO_PEERSEC	31
 #define	LINUX_SO_SNDBUFFORCE	32
 #define	LINUX_SO_RCVBUFFORCE	33
 #define	LINUX_SO_PROTOCOL	38
Index: sys/compat/linux/linux_socket.c
===================================================================
--- sys/compat/linux/linux_socket.c
+++ sys/compat/linux/linux_socket.c
@@ -82,6 +82,8 @@
 #include <compat/linux/linux_timer.h>
 #include <compat/linux/linux_util.h>
 
+#define	SECURITY_CONTEXT_STRING	"unconfined"
+
 static int linux_sendmsg_common(struct thread *, l_int, struct l_msghdr *,
 					l_uint);
 static int linux_recvmsg_common(struct thread *, l_int, struct l_msghdr *,
@@ -1875,6 +1877,23 @@
 	level = linux_to_bsd_sockopt_level(args->level);
 	switch (level) {
 	case SOL_SOCKET:
+		if (args->optname == LINUX_SO_PEERSEC) {
+			len = sizeof(SECURITY_CONTEXT_STRING);
+			if (args->optlen < len) {
+				error = ERANGE;
+				error = copyout(&len,
+				    PTRIN(args->optlen), sizeof(len));
+				return (error);
+			}
+
+			error = copyout(SECURITY_CONTEXT_STRING,
+			    PTRIN(args->optval),
+			    sizeof(SECURITY_CONTEXT_STRING));
+			if (error == 0)
+				error = copyout(&len, PTRIN(args->optlen),
+				    sizeof(len));
+			return (error);
+		}
 		name = linux_to_bsd_so_sockopt(args->optname);
 		switch (name) {
 		case LOCAL_CREDS_PERSISTENT: