diff --git a/ChangeLog b/ChangeLog
index 2eff9f5e80..909f2e4fc2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Tue Jun  5 20:13:15 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* object.c (rb_obj_init_copy): should check if trusted too.
+
 Tue Jun  5 19:59:13 2012  Tanaka Akira  <akr@fsij.org>
 
 	* process.c (strtok): declaration removed because it is not used.
diff --git a/enumerator.c b/enumerator.c
index e62eabf61f..f01ddd51e6 100644
--- a/enumerator.c
+++ b/enumerator.c
@@ -373,6 +373,7 @@ enumerator_init_copy(VALUE obj, VALUE orig)
 {
     struct enumerator *ptr0, *ptr1;
 
+    if (!OBJ_INIT_COPY(obj, orig)) return obj;
     ptr0 = enumerator_ptr(orig);
     if (ptr0->fib) {
 	/* Fibers cannot be copied */
@@ -1146,6 +1147,8 @@ generator_init_copy(VALUE obj, VALUE orig)
 {
     struct generator *ptr0, *ptr1;
 
+    if (!OBJ_INIT_COPY(obj, orig)) return obj;
+
     ptr0 = generator_ptr(orig);
 
     TypedData_Get_Struct(obj, struct generator, &generator_data_type, ptr1);
diff --git a/file.c b/file.c
index 846f3147f9..6fc64a4739 100644
--- a/file.c
+++ b/file.c
@@ -4470,12 +4470,7 @@ rb_stat_init_copy(VALUE copy, VALUE orig)
 {
     struct stat *nst;
 
-    if (copy == orig) return orig;
-    rb_check_frozen(copy);
-    /* need better argument type check */
-    if (!rb_obj_is_instance_of(orig, rb_obj_class(copy))) {
-	rb_raise(rb_eTypeError, "wrong argument class");
-    }
+    if (!OBJ_INIT_COPY(copy, orig)) return copy;
     if (DATA_PTR(copy)) {
 	xfree(DATA_PTR(copy));
 	DATA_PTR(copy) = 0;
diff --git a/include/ruby/intern.h b/include/ruby/intern.h
index 9690964ac8..a3d583c2ea 100644
--- a/include/ruby/intern.h
+++ b/include/ruby/intern.h
@@ -252,6 +252,9 @@ rb_check_trusted_inline(VALUE obj)
 #define rb_check_trusted(obj) rb_check_trusted_inline(obj)
 #endif
 
+#define OBJ_INIT_COPY(obj, orig) \
+    ((obj) != (orig) && (rb_obj_init_copy((obj), (orig)), 1))
+
 /* eval.c */
 int rb_sourceline(void);
 const char *rb_sourcefile(void);
diff --git a/io.c b/io.c
index 3d4fe54848..f24bfbb5b0 100644
--- a/io.c
+++ b/io.c
@@ -6387,7 +6387,7 @@ rb_io_init_copy(VALUE dest, VALUE io)
     off_t pos;
 
     io = rb_io_get_io(io);
-    if (dest == io) return dest;
+    if (!OBJ_INIT_COPY(dest, io)) return dest;
     GetOpenFile(io, orig);
     MakeOpenFile(dest, fptr);
 
@@ -7286,6 +7286,7 @@ argf_initialize(VALUE argf, VALUE argv)
 static VALUE
 argf_initialize_copy(VALUE argf, VALUE orig)
 {
+    if (!OBJ_INIT_COPY(argf, orig)) return argf;
     ARGF = argf_of(orig);
     ARGF.argv = rb_obj_dup(ARGF.argv);
     if (ARGF.inplace) {
diff --git a/object.c b/object.c
index dbb8db63dd..1177466d7f 100644
--- a/object.c
+++ b/object.c
@@ -342,6 +342,7 @@ rb_obj_init_copy(VALUE obj, VALUE orig)
 {
     if (obj == orig) return obj;
     rb_check_frozen(obj);
+    rb_check_trusted(obj);
     if (TYPE(obj) != TYPE(orig) || rb_obj_class(obj) != rb_obj_class(orig)) {
 	rb_raise(rb_eTypeError, "initialize_copy should take same class object");
     }
diff --git a/random.c b/random.c
index 9dbcbd1d62..d05fe6d9c6 100644
--- a/random.c
+++ b/random.c
@@ -596,9 +596,14 @@ random_get_seed(VALUE obj)
 static VALUE
 random_copy(VALUE obj, VALUE orig)
 {
-    rb_random_t *rnd1 = get_rnd(obj);
-    rb_random_t *rnd2 = get_rnd(orig);
-    struct MT *mt = &rnd1->mt;
+    rb_random_t *rnd1, *rnd2;
+    struct MT *mt;
+
+    if (!OBJ_INIT_COPY(obj, orig)) return obj;
+
+    rnd1 = get_rnd(obj);
+    rnd2 = get_rnd(orig);
+    mt = &rnd1->mt;
 
     *rnd1 = *rnd2;
     mt->next = mt->state + numberof(mt->state) - mt->left + 1;
diff --git a/re.c b/re.c
index 500173d3cb..4191d5bcb8 100644
--- a/re.c
+++ b/re.c
@@ -939,11 +939,8 @@ match_init_copy(VALUE obj, VALUE orig)
 {
     struct rmatch *rm;
 
-    if (obj == orig) return obj;
+    if (!OBJ_INIT_COPY(obj, orig)) return obj;
 
-    if (!rb_obj_is_instance_of(orig, rb_obj_class(obj))) {
-	rb_raise(rb_eTypeError, "wrong argument class");
-    }
     RMATCH(obj)->str = RMATCH(orig)->str;
     RMATCH(obj)->regexp = RMATCH(orig)->regexp;
 
@@ -3260,12 +3257,7 @@ rb_reg_init_copy(VALUE copy, VALUE re)
     const char *s;
     long len;
 
-    if (copy == re) return copy;
-    rb_check_frozen(copy);
-    /* need better argument type check */
-    if (!rb_obj_is_instance_of(re, rb_obj_class(copy))) {
-	rb_raise(rb_eTypeError, "wrong argument type");
-    }
+    if (!OBJ_INIT_COPY(copy, re)) return copy;
     rb_reg_check(re);
     s = RREGEXP_SRC_PTR(re);
     len = RREGEXP_SRC_LEN(re);
diff --git a/struct.c b/struct.c
index 8168f62bb1..91d562b97c 100644
--- a/struct.c
+++ b/struct.c
@@ -606,11 +606,7 @@ rb_struct_to_h(VALUE s)
 VALUE
 rb_struct_init_copy(VALUE copy, VALUE s)
 {
-    if (copy == s) return copy;
-    rb_check_frozen(copy);
-    if (!rb_obj_is_instance_of(s, rb_obj_class(copy))) {
-	rb_raise(rb_eTypeError, "wrong argument class");
-    }
+    if (!OBJ_INIT_COPY(copy, s)) return copy;
     if (RSTRUCT_LEN(copy) != RSTRUCT_LEN(s)) {
 	rb_raise(rb_eTypeError, "struct size mismatch");
     }
diff --git a/test/ruby/test_object.rb b/test/ruby/test_object.rb
index d63886a81e..70dcd04201 100644
--- a/test/ruby/test_object.rb
+++ b/test/ruby/test_object.rb
@@ -764,4 +764,36 @@ class TestObject < Test::Unit::TestCase
       assert_equal((eval("raise #{code}") rescue $!.inspect), out.chomp, bug5473)
     end
   end
+
+  def assert_not_initialize_copy
+    a = yield
+    b = yield
+    assert_nothing_raised("copy") {a.instance_eval {initialize_copy(b)}}
+    c = a.dup.freeze
+    assert_raise(RuntimeError, "frozen") {c.instance_eval {initialize_copy(b)}}
+    d = a.dup.trust
+    assert_raise(SecurityError, "untrust") do
+      proc {
+        $SAFE = 4
+        d.instance_eval {initialize_copy(b)}
+      }.call
+    end
+    [a, b, c, d]
+  end
+
+  def test_bad_initialize_copy
+    assert_not_initialize_copy {Object.new}
+    assert_not_initialize_copy {[].to_enum}
+    assert_not_initialize_copy {Enumerator::Generator.new {}}
+    assert_not_initialize_copy {Enumerator::Yielder.new {}}
+    assert_not_initialize_copy {File.stat(__FILE__)}
+    assert_not_initialize_copy {open(__FILE__)}.each(&:close)
+    assert_not_initialize_copy {ARGF.class.new}
+    assert_not_initialize_copy {Random.new}
+    assert_not_initialize_copy {//}
+    assert_not_initialize_copy {/.*/.match("foo")}
+    st = Struct.new(:foo)
+    assert_not_initialize_copy {st.new}
+    assert_not_initialize_copy {Time.now}
+  end
 end
diff --git a/time.c b/time.c
index b0a2be2455..0d771d2715 100644
--- a/time.c
+++ b/time.c
@@ -3425,8 +3425,7 @@ time_init_copy(VALUE copy, VALUE time)
 {
     struct time_object *tobj, *tcopy;
 
-    if (copy == time) return copy;
-    time_modify(copy);
+    if (!OBJ_INIT_COPY(copy, time)) return copy;
     GetTimeval(time, tobj);
     GetTimeval(copy, tcopy);
     MEMCPY(tcopy, tobj, struct time_object, 1);