diff --git a/src/CanvasRenderingContext2d.cc b/src/CanvasRenderingContext2d.cc
index cedcfac..437893a 100644
--- a/src/CanvasRenderingContext2d.cc
+++ b/src/CanvasRenderingContext2d.cc
@@ -1009,8 +1009,10 @@ Context2d::SetShadowColor(Local<String> prop, Local<Value> val, const AccessorIn
 
 Handle<Value>
 Context2d::GetShadowColor(Local<String> prop, const AccessorInfo &info) {
+  char buf[64];
   Context2d *context = ObjectWrap::Unwrap<Context2d>(info.This());
-  return String::New(rgba_to_string(context->state->shadow));
+  rgba_to_string(context->state->shadow, buf);
+  return String::New(buf);
 }
 
 /*
diff --git a/src/color.cc b/src/color.cc
index 4341d78..ab4a8f1 100644
--- a/src/color.cc
+++ b/src/color.cc
@@ -239,9 +239,8 @@ rgba_create(uint32_t rgba) {
  * Return a string representation of the color.
  */
 
-char *
-rgba_to_string(rgba_t rgba) {
-  char *buf = (char *) malloc(64);
+void
+rgba_to_string(rgba_t rgba, char *buf) {
   if (1 == rgba.a) {
     sprintf(buf, "#%.2X%.2X%.2X"
       , (int) (rgba.r * 255)
@@ -254,7 +253,6 @@ rgba_to_string(rgba_t rgba) {
       , (int) (rgba.b * 255)
       , rgba.a);
   }
-  return buf;
 }
 
 /*
diff --git a/src/color.h b/src/color.h
index 4119316..10de606 100644
--- a/src/color.h
+++ b/src/color.h
@@ -30,8 +30,8 @@ rgba_create(uint32_t rgba);
 int32_t
 rgba_from_string(const char *str, short *ok);
 
-char *
-rgba_to_string(rgba_t rgba);
+void
+rgba_to_string(rgba_t rgba, char *buf);
 
 void
 rgba_inspect(int32_t rgba);