Add checks to disallow extending FFI::Library into a non-module

2 files changed, 11 insertions, 1 deletions

diff --git a/ext/ffi_c/Function.c b/ext/ffi_c/Function.c
index 08d563f..97abe94 100644
--- a/ext/ffi_c/Function.c
+++ b/ext/ffi_c/Function.c
@@ -249,7 +249,13 @@ function_attach(VALUE self, VALUE module, VALUE name)
     Data_Get_Struct(self, Function, fn);
 
     if (fn->info->parameterCount == -1) {
-        rb_raise(rb_eRuntimeError, "Cannot attach variadic functions");
+        rb_raise(rb_eRuntimeError, "cannot attach variadic functions");
+        return Qnil;
+    }
+
+    if (!rb_obj_is_kind_of(module, rb_cModule)) {
+        rb_raise(rb_eRuntimeError, "trying to attach function to non-module");
+        return Qnil;
     }
 
     if (fn->methodHandle == NULL) {
diff --git a/lib/ffi/library.rb b/lib/ffi/library.rb
index d8524b1..1ba8475 100644
--- a/lib/ffi/library.rb
+++ b/lib/ffi/library.rb
@@ -34,6 +34,10 @@ module FFI
     CURRENT_PROCESS = FFI::CURRENT_PROCESS
     LIBC = FFI::Platform::LIBC
 
+    def self.extended(mod)
+      raise RuntimeError.new("must only be extended by module") unless mod.kind_of?(Module)
+    end
+
     def ffi_lib(*names)
 
       ffi_libs = names.map do |name|