fix(dnshack): Don't try resolving ip addresses

Hypfer · Feb 20, 2021 · b8c456d · b8c456d
1 parent f7eb451
commit b8c456d
Showing 1 changed file with 28 additions and 10 deletions.
diff --git a/lib/DnsHack.js b/lib/DnsHack.js
@@ -71,21 +71,33 @@ class DnsHack {
                 ) {
                     Logger.trace("Intercepting dns.lookup call for", hostname);
 
-                    dns.resolve4(hostname, (err, addresses) => {
-                        if (err && err.code === "ENOTFOUND") {
-                            dns.resolve6(hostname, (err, addresses) => {
-                                if (err) {
+                    if (typeof hostname === "string") {
+                        const trimmedHostname = hostname.trim();
+
+                        if (trimmedHostname.match(IPV4REGEX) !== null) {
+                            callback(null, trimmedHostname, 4);
+                        } else if (trimmedHostname.match(IPV6REGEX) !== null) {
+                            callback(null, trimmedHostname, 6);
+                        } else {
+                            dns.resolve4(hostname, (err, addresses) => {
+                                if (err && err.code === "ENOTFOUND") {
+                                    dns.resolve6(hostname, (err, addresses) => {
+                                        if (err) {
+                                            callback(err);
+                                        } else {
+                                            callback(null, addresses[0], 6);
+                                        }
+                                    });
+                                } else if (err) {
                                     callback(err);
                                 } else {
-                                    callback(null, addresses[0], 6);
+                                    callback(null, addresses[0], 4);
                                 }
                             });
-                        } else if (err) {
-                            callback(err);
-                        } else {
-                            callback(null, addresses[0], 4);
                         }
-                    });
+                    } else {
+                        callback(new Error("Invalid Hostname"));
+                    }
                 } else {
                     return realLookup(hostname, options, callback);
                 }
@@ -109,4 +121,10 @@ class DnsHack {
     }
 }
 
+//https://www.oreilly.com/library/view/regular-expressions-cookbook/9780596802837/ch07s16.html
+const IPV4REGEX = /^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/;
+
+//https://www.oreilly.com/library/view/regular-expressions-cookbook/9781449327453/ch08s17.html
+const IPV6REGEX = /^(?:[A-F0-9]{1,4}:){7}[A-F0-9]{1,4}$/i;
+
 module.exports = DnsHack;