url: runtime-deprecate url.parse() with invalid ports

These URLs throw with WHATWG URL. They are permitted with url.parse()
but that allows potential host spoofing by sending a domain name as the
port.

doc/api/deprecations.md

@@ -3284,7 +3284,7 @@ Node-API callbacks.
 <!-- YAML
 changes:
   - version:
-      - v19.0.0
+    - v19.0.0
     pr-url: https://github.com/nodejs/node/pull/44919
     description: Documentation-only deprecation.
 -->
@@ -3295,6 +3295,22 @@ Type: Documentation-only
 have security implications. Use the [WHATWG URL API][] instead. CVEs are not
 issued for `url.parse()` vulnerabilities.
 
+### DEP0170: Invalid port when using url.parse()
+
+<!-- YAML
+changes:
+  - version:
+    - REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/45526
+    description: Runtime deprecation.
+-->
+
+Type: Runtime
+
+[`url.parse()`][] accepts URLs with ports that are not numbers. This behavior
+might result in host name spoofing with unexpected input. These URLs will throw
+an error in future versions of Node.js, as the [WHATWG URL API][] does already.
+
 [NIST SP 800-38D]: https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-38d.pdf
 [RFC 6066]: https://tools.ietf.org/html/rfc6066#section-3
 [RFC 8247 Section 2.4]: https://www.rfc-editor.org/rfc/rfc8247#section-2.4

lib/url.js

@@ -387,7 +387,7 @@ Url.prototype.parse = function parse(url, parseQueryString, slashesDenoteHost) {
 
     // validate a little.
     if (!ipv6Hostname) {
-      rest = getHostname(this, rest, hostname);
+      rest = getHostname(this, rest, hostname, url);
     }
 
     if (this.hostname.length > hostnameMaxLen) {
@@ -506,7 +506,7 @@ Url.prototype.parse = function parse(url, parseQueryString, slashesDenoteHost) {
   return this;
 };
 
-function getHostname(self, rest, hostname) {
+function getHostname(self, rest, hostname, url) {
   for (let i = 0; i < hostname.length; ++i) {
     const code = hostname.charCodeAt(i);
     const isValid = (code !== CHAR_FORWARD_SLASH &&
@@ -516,6 +516,13 @@ function getHostname(self, rest, hostname) {
                      code !== CHAR_COLON);
 
     if (!isValid) {
+      // If leftover starts with :, then it represents an invalid port.
+      // But url.parse() is lenient about it for now.
+      // Issue a warning and continue.
+      if (code === CHAR_COLON) {
+        const detail = `The URL ${url} is invalid. Future versions of Node.js will throw an error.`;
+        process.emitWarning(detail, 'DeprecationWarning', 'DEP0170');
+      }
       self.hostname = hostname.slice(0, i);
       return `/${hostname.slice(i)}${rest}`;
     }

test/parallel/test-url-parse-invalid-input.js

@@ -74,3 +74,22 @@ if (common.hasIntl) {
                 (e) => e.code === 'ERR_INVALID_URL',
                 'parsing http://\u00AD/bad.com/');
 }
+
+{
+  const badURLs = [
+    'https://evil.com:.example.com',
+    'git+ssh://git@github.com:npm/npm',
+  ];
+  const expectedWarnings = badURLs.map(
+    (url) => [
+      `The URL ${url} is invalid. Future versions of Node.js will throw an error.`,
+      'DEP0170',
+    ]
+  );
+  common.expectWarning({
+    DeprecationWarning: expectedWarnings,
+  });
+  badURLs.forEach((badURL) => {
+    url.parse(badURL);
+  });
+}