1 files changed, 6 insertions, 0 deletions
diff --git a/ext/socket/init.c b/ext/socket/init.c
index ed85e0b503..85cc3de4f9 100644
--- a/ext/socket/init.c
+++ b/ext/socket/init.c
@@ -43,6 +43,12 @@ VALUE
 rsock_init_sock(VALUE sock, int fd)
 {
     rb_io_t *fp;
+    struct stat sbuf;
+
+    if (fstat(fd, &sbuf) < 0)
+        rb_sys_fail(0);
+    if (!S_ISSOCK(sbuf.st_mode))
+        rb_raise(rb_eArgError, "not a socket file descriptor");
 
     MakeOpenFile(sock, fp);
     fp->fd = fd;