From 3da402a8d4c71f374016ccdd11fe475b39e2bdf1 Mon Sep 17 00:00:00 2001
From: Jan Oberhauser <jan.oberhauser@gmail.com>
Date: Fri, 13 Dec 2019 11:23:30 -0600
Subject: [PATCH] :sparkles: Allow to use built-in modules in Function-Nodes if
 configured

---
 docs/configuration.md                          | 18 ++++++++++++++++++
 packages/nodes-base/nodes/Function.node.ts     | 11 +++++++++--
 packages/nodes-base/nodes/FunctionItem.node.ts | 11 +++++++++--
 3 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/docs/configuration.md b/docs/configuration.md
index 51473c0ef..fb612d31f 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -100,6 +100,24 @@ export N8N_CUSTOM_EXTENSIONS="/home/jim/n8n/custom-nodes;/data/n8n/nodes"
 ```
 
 
+## Use built-in modules in Function-Nodes
+
+By default is it for security reasons not allowed to import modules in Function-Nodes.
+It is, however, possible to lift that restriction for built-in modules by setting the
+environment variable `NODE_FUNCTION_ALLOW_BUILTIN`.
+
+```bash
+# Allows usage of all builtin modules
+export NODE_FUNCTION_ALLOW_BUILTIN=*
+
+# Allows usage of only crypto
+export NODE_FUNCTION_ALLOW_BUILTIN=crypto
+
+# Allows usage of only crypto and fs
+export NODE_FUNCTION_ALLOW_BUILTIN=crypto,fs
+```
+
+
 ## Timezone
 
 The timezone is set by default to "America/New_York". It gets for example used by the
diff --git a/packages/nodes-base/nodes/Function.node.ts b/packages/nodes-base/nodes/Function.node.ts
index b93fa233f..373411d2d 100644
--- a/packages/nodes-base/nodes/Function.node.ts
+++ b/packages/nodes-base/nodes/Function.node.ts
@@ -59,14 +59,21 @@ export class Function implements INodeType {
 		// By default use data from first item
 		Object.assign(sandbox, sandbox.$item(0));
 
-		const vm = new NodeVM({
+		const options = {
 			console: 'inherit',
 			sandbox,
 			require: {
 				external: false,
+				builtin: [] as string[],
 				root: './',
 			}
-		});
+		};
+
+		if (process.env.NODE_FUNCTION_ALLOW_BUILTIN) {
+			options.require.builtin = process.env.NODE_FUNCTION_ALLOW_BUILTIN.split(',');
+		}
+
+		const vm = new NodeVM(options);
 
 		// Get the code to execute
 		const functionCode = this.getNodeParameter('functionCode', 0) as string;
diff --git a/packages/nodes-base/nodes/FunctionItem.node.ts b/packages/nodes-base/nodes/FunctionItem.node.ts
index a3c76f7e6..d1664c7d3 100644
--- a/packages/nodes-base/nodes/FunctionItem.node.ts
+++ b/packages/nodes-base/nodes/FunctionItem.node.ts
@@ -64,14 +64,21 @@ export class FunctionItem implements INodeType {
 		const dataProxy = this.getWorkflowDataProxy();
 		Object.assign(sandbox, dataProxy);
 
-		const vm = new NodeVM({
+		const options = {
 			console: 'inherit',
 			sandbox,
 			require: {
 				external: false,
+				builtin: [] as string[],
 				root: './',
 			}
-		});
+		};
+
+		if (process.env.NODE_FUNCTION_ALLOW_BUILTIN) {
+			options.require.builtin = process.env.NODE_FUNCTION_ALLOW_BUILTIN.split(',');
+		}
+
+		const vm = new NodeVM(options);
 
 		// Get the code to execute
 		const functionCode = this.getNodeParameter('functionCode') as string;