Set rejectUnauthorized to true by default (#3149)

Resolve CVE-2020-240-25 by setting rejectUnauthorized to true by default.

Add configuration flag to override this to false if necessary.

extract rejectUnauthorized download option to its own file.

Add doc option to README.md.

README.md

@@ -596,12 +596,13 @@ When compiling a directory `--source-map` can either be a boolean value or a dir
 
 node-sass supports different configuration parameters to change settings related to the sass binary such as binary name, binary path or alternative download path. Following parameters are supported by node-sass:
 
-Variable name    | .npmrc parameter | Process argument   | Value
------------------|------------------|--------------------|------
-SASS_BINARY_NAME | sass_binary_name | --sass-binary-name | path
-SASS_BINARY_SITE | sass_binary_site | --sass-binary-site | URL
-SASS_BINARY_PATH | sass_binary_path | --sass-binary-path | path
-SASS_BINARY_DIR  | sass_binary_dir  | --sass-binary-dir  | path
+Variable name            | .npmrc parameter         | Process argument           | Value
+-------------------------|--------------------------|----------------------------|------
+SASS_BINARY_NAME         | sass_binary_name         | --sass-binary-name         | path
+SASS_BINARY_SITE         | sass_binary_site         | --sass-binary-site         | URL
+SASS_BINARY_PATH         | sass_binary_path         | --sass-binary-path         | path
+SASS_BINARY_DIR          | sass_binary_dir          | --sass-binary-dir          | path
+SASS_REJECT_UNAUTHORIZED | sass_reject_unauthorized | --sass-reject-unauthorized | value
 
 These parameters can be used as environment variable:
 
@@ -615,6 +616,8 @@ As a process argument:
 
 * E.g. `npm install node-sass --sass-binary-site=http://example.com/`
 
+If you are using self-signed certificates for your binary then `SASS_REJECT_UNAUTHORIZED` will override (rejectUnauthorized)[https://nodejs.org/docs/latest/api/tls.html#tls_tls_createserver_options_secureconnectionlistener].
+
 ## Post-install Build
 
 Install runs only two Mocha tests to see if your machine can use the pre-built [LibSass] which will save some time during install. If any tests fail it will build from source.

scripts/util/downloadoptions.js

@@ -1,5 +1,6 @@
 var proxy = require('./proxy'),
-  userAgent = require('./useragent');
+  userAgent = require('./useragent'),
+  rejectUnauthorized = require('./rejectUnauthorized');
 
 /**
  * The options passed to request when downloading the bibary
@@ -14,7 +15,7 @@ var proxy = require('./proxy'),
  */
 module.exports = function() {
   var options = {
-    rejectUnauthorized: false,
+    rejectUnauthorized: rejectUnauthorized(),
     timeout: 60000,
     headers: {
       'User-Agent': userAgent(),

scripts/util/rejectUnauthorized.js

@@ -0,0 +1,46 @@
+var pkg = require('../../package.json');
+
+/**
+ * Get the value of a CLI argument
+ *
+ * @param {String} name
+ * @param {Array} args
+ * @api private
+ */
+ function getArgument(name, args) {
+  var flags = args || process.argv.slice(2),
+    index = flags.lastIndexOf(name);
+
+  if (index === -1 || index + 1 >= flags.length) {
+    return null;
+  }
+
+  return flags[index + 1];
+}
+
+/**
+ * Get the value of reject-unauthorized
+ * If environment variable SASS_REJECT_UNAUTHORIZED is non-zero,
+ * .npmrc variable sass_reject_unauthorized or
+ * process argument --sass-reject_unauthorized is provided,
+ * set rejectUnauthorized to true
+ * Else set to false by default
+ *
+ * @return {Boolean} The value of rejectUnauthorized
+ * @api private
+ */
+module.exports = function() {
+  var rejectUnauthorized = false;
+
+  if (getArgument('--sass-reject-unauthorized')) {
+    rejectUnauthorized = getArgument('--sass-reject-unauthorized');
+  } else if (process.env.SASS_REJECT_UNAUTHORIZED !== '0') {
+    rejectUnauthorized = true;
+  } else if (process.env.npm_config_sass_reject_unauthorized) {
+    rejectUnauthorized = process.env.npm_config_sass_reject_unauthorized;
+  } else if (pkg.nodeSassConfig && pkg.nodeSassConfig.rejectUnauthorized) {
+    rejectUnauthorized = pkg.nodeSassConfig.rejectUnauthorized;
+  } 
+
+  return rejectUnauthorized;
+};

test/downloadoptions.js

@@ -8,7 +8,7 @@ describe('util', function() {
     describe('without a proxy', function() {
       it('should look as we expect', function() {
         var expected = {
-          rejectUnauthorized: false,
+          rejectUnauthorized: true,
           timeout: 60000,
           headers: {
             'User-Agent': ua(),
@@ -33,7 +33,7 @@ describe('util', function() {
 
       it('should look as we expect', function() {
         var expected = {
-          rejectUnauthorized: false,
+          rejectUnauthorized: true,
           proxy: proxy,
           timeout: 60000,
           headers: {
@@ -57,6 +57,25 @@ describe('util', function() {
         delete process.env.HTTP_PROXY;
       });
 
+      it('should look as we expect', function() {
+        var expected = {
+          rejectUnauthorized: true,
+          timeout: 60000,
+          headers: {
+            'User-Agent': ua(),
+          },
+          encoding: null,
+        };
+
+        assert.deepStrictEqual(opts(), expected);
+      });
+    });
+
+    describe('with SASS_REJECT_UNAUTHORIZED set to false', function() {
+      beforeEach(function() {
+        process.env.SASS_REJECT_UNAUTHORIZED = '0';
+      });
+
       it('should look as we expect', function() {
         var expected = {
           rejectUnauthorized: false,
@@ -70,5 +89,47 @@ describe('util', function() {
         assert.deepStrictEqual(opts(), expected);
       });
     });
+
+    describe('with SASS_REJECT_UNAUTHORIZED set to true', function() {
+      beforeEach(function() {
+        process.env.SASS_REJECT_UNAUTHORIZED = '1';
+      });
+
+      it('should look as we expect', function() {
+        var expected = {
+          rejectUnauthorized: true,
+          timeout: 60000,
+          headers: {
+            'User-Agent': ua(),
+          },
+          encoding: null,
+        };
+
+        assert.deepStrictEqual(opts(), expected);
+      });
+    });
+
+    describe('with npm_config_sass_reject_unauthorized set to true', function() {
+      beforeEach(function() {
+        process.env.npm_config_sass_reject_unauthorized = true;
+      });
+
+      it('should look as we expect', function() {
+        var expected = {
+          rejectUnauthorized: true,
+          timeout: 60000,
+          headers: {
+            'User-Agent': ua(),
+          },
+          encoding: null,
+        };
+
+        assert.deepStrictEqual(opts(), expected);
+      });
+
+      afterEach(function() {
+        process.env.npm_config_sass_reject_unauthorized = undefined;
+      });
+    });
   });
 });