diff --git a/userdiff.c b/userdiff.c
index b5412e6bc3..7547874aa2 100644
--- a/userdiff.c
+++ b/userdiff.c
@@ -509,6 +509,13 @@ int userdiff_config(const char *k, const char *v)
 		drv->algorithm = drv->algorithm_owned;
 		return ret;
 	}
+	if (!strcmp(type, "process")) {
+		int ret;
+		FREE_AND_NULL(drv->process_owned);
+		ret = git_config_string(&drv->process_owned, k, v);
+		drv->process = drv->process_owned;
+		return ret;
+	}
 
 	return 0;
 }
diff --git a/userdiff.h b/userdiff.h
index 827361b0bc..51c26e0d41 100644
--- a/userdiff.h
+++ b/userdiff.h
@@ -31,6 +31,8 @@ struct userdiff_driver {
 	char *textconv_owned;
 	struct notes_cache *textconv_cache;
 	int textconv_want_cache;
+	const char *process;
+	char *process_owned;
 };
 enum userdiff_driver_type {
 	USERDIFF_DRIVER_TYPE_BUILTIN = 1<<0,