Patch from trunk for CVE-2012-4464, CVE-2012-4466
Part for test/ruby/test_exception.rb was adjusted for ruby 1.9.3

Mamoru Tasaka <mtasaka@fedoraproject.org>

------------------------------------------------------------------------
r37068 | shugo | 2012-10-03 02:25:10 +0900 (Wed, 03 Oct 2012) | 2 lines

* error.c (exc_to_s, name_err_to_s, name_err_mesg_to_str): do not
  taint messages.
------------------------------------------------------------------------
Index: error.c
===================================================================
--- error.c	(revision 37067)
+++ error.c	(revision 37068)
@@ -635,7 +635,6 @@
 
     if (NIL_P(mesg)) return rb_class_name(CLASS_OF(exc));
     r = rb_String(mesg);
-    OBJ_INFECT(r, exc);
     return r;
 }
 
@@ -996,11 +995,7 @@
 
     if (NIL_P(mesg)) return rb_class_name(CLASS_OF(exc));
     StringValue(str);
-    if (str != mesg) {
-	rb_iv_set(exc, "mesg", mesg = str);
-    }
-    OBJ_INFECT(mesg, exc);
-    return mesg;
+    return str;
 }
 
 /*
@@ -1131,7 +1126,6 @@
 	args[2] = d;
 	mesg = rb_f_sprintf(NAME_ERR_MESG_COUNT, args);
     }
-    OBJ_INFECT(mesg, obj);
     return mesg;
 }
 
Index: test/ruby/test_exception.rb
===================================================================
--- test/ruby/test_exception.rb	(revision 37067)
+++ test/ruby/test_exception.rb	(modified)
@@ -333,4 +333,54 @@
       load(t.path)
     end
   end
+
+  def test_to_s_taintness_propagation
+    for exc in [Exception, NameError]
+      m = "abcdefg"
+      e = exc.new(m)
+      e.taint
+      s = e.to_s
+      assert_equal(false, m.tainted?,
+                   "#{exc}#to_s should not propagate taintness")
+      assert_equal(false, s.tainted?,
+                   "#{exc}#to_s should not propagate taintness")
+    end
+    
+    o = Object.new
+    def o.to_str
+      "foo"
+    end
+    o.taint
+    e = NameError.new(o)
+    s = e.to_s
+    assert_equal(false, s.tainted?)
+  end
+
+  def test_exception_to_s_should_not_propagate_untrustedness
+    favorite_lang = "Ruby"
+
+    for exc in [Exception, NameError]
+      assert_raise(SecurityError) do
+        lambda {
+          $SAFE = 4
+          exc.new(favorite_lang).to_s
+          favorite_lang.replace("Python")
+        }.call
+      end
+    end
+
+    assert_raise(SecurityError) do
+      lambda {
+        $SAFE = 4
+        o = Object.new
+        o.singleton_class.send(:define_method, :to_str) {
+          favorite_lang
+        }
+        NameError.new(o).to_s
+        favorite_lang.replace("Python")
+      }.call
+    end
+
+    assert_equal("Ruby", favorite_lang)
+  end
 end