Update email template validation & tests

packages/plugins/users-permissions/server/controllers/validation/__tests__/email-template.test.js

@@ -17,6 +17,11 @@ describe('isValidEmailTemplate', () => {
     expect(isValidEmailTemplate('<%CODE%>')).toBe(false);
     expect(isValidEmailTemplate('${CODE}')).toBe(false);
     expect(isValidEmailTemplate('${ CODE }')).toBe(false);
+    expect(
+      isValidEmailTemplate(
+        '<%=`${ console.log({ "remote-execution": { "foo": "bar" }/*<>%=*/ }) }`%>'
+      )
+    ).toBe(false);
   });
 
   test('Fails on non authorized keys', () => {

packages/plugins/users-permissions/server/controllers/validation/email-template.js

@@ -1,8 +1,17 @@
 'use strict';
 
 const _ = require('lodash');
+const {
+  template: { createLooseInterpolationRegExp, createStrictInterpolationRegExp },
+} = require('@strapi/utils');
+
+const invalidPatternsRegexes = [
+  // Ignore "evaluation" patterns: <% ... %>
+  /<%[^=]([\s\S]*?)%>/m,
+  // Ignore basic string interpolations
+  /\${([^{}]*)}/m,
+];
 
-const invalidPatternsRegexes = [/<%[^=]([^<>%]*)%>/m, /\${([^{}]*)}/m];
 const authorizedKeys = [
   'URL',
   'ADMIN_URL',
@@ -19,27 +28,42 @@ const matchAll = (pattern, src) => {
   let match;
 
   const regexPatternWithGlobal = RegExp(pattern, 'g');
+
   // eslint-disable-next-line no-cond-assign
   while ((match = regexPatternWithGlobal.exec(src))) {
     const [, group] = match;
 
     matches.push(_.trim(group));
   }
+
   return matches;
 };
 
 const isValidEmailTemplate = (template) => {
+  // Check for known invalid patterns
   for (const reg of invalidPatternsRegexes) {
     if (reg.test(template)) {
       return false;
     }
   }
 
-  const matches = matchAll(/<%=([^<>%=]*)%>/, template);
-  for (const match of matches) {
-    if (!authorizedKeys.includes(match)) {
-      return false;
-    }
+  const interpolation = {
+    // Strict interpolation pattern to match only valid groups
+    strict: createStrictInterpolationRegExp(authorizedKeys),
+    // Weak interpolation pattern to match as many group as possible.
+    loose: createLooseInterpolationRegExp(),
+  };
+
+  // Compute both strict & loose matches
+  const strictMatches = matchAll(interpolation.strict, template);
+  const looseMatches = matchAll(interpolation.loose, template);
+
+  // If we have more matches with the loose RegExp than with the strict one,
+  // then it means that at least one of the interpolation group is invalid
+  // Note: In the future, if we wanted to give more details for error formatting
+  // purposes, we could return the difference between the two arrays
+  if (looseMatches.length > strictMatches.length) {
+    return false;
   }
 
   return true;