From e8beb245da35794b13c1f847f0fbbc278fa1dfb3 Mon Sep 17 00:00:00 2001
From: spiral <spiral@spiral.sh>
Date: Fri, 19 Nov 2021 10:58:12 -0500
Subject: [PATCH] fix(webhooks): fix error when DNS entry has non-ipv4
 addresses

---
 PluralKit.Bot/Commands/Api.cs             |  9 +++------
 PluralKit.Core/Dispatch/DispatchModels.cs | 18 +++++++++++++-----
 2 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/PluralKit.Bot/Commands/Api.cs b/PluralKit.Bot/Commands/Api.cs
index ac276976..75ef3f5d 100644
--- a/PluralKit.Bot/Commands/Api.cs
+++ b/PluralKit.Bot/Commands/Api.cs
@@ -110,7 +110,7 @@ namespace PluralKit.Bot
                 await _repo.UpdateSystem(ctx.System.Id, new()
                 {
                     WebhookUrl = null,
-                    Token = null,
+                    WebhookToken = null,
                 });
 
                 await ctx.Reply($"{Emojis.Success} System webhook URL removed.");
@@ -119,17 +119,14 @@ namespace PluralKit.Bot
 
             var newUrl = ctx.RemainderOrNull();
             if (!await DispatchExt.ValidateUri(newUrl))
-            {
-                await ctx.Reply($"New URL '{newUrl}' is invalid. Are you sure this is a valid, publicly accessible URL?");
-                return;
-            }
+                throw new PKError($"The URL {newUrl.AsCode()} is invalid or I cannot access it. Are you sure this is a valid, publicly accessible URL?");
 
             var newToken = StringUtils.GenerateToken();
 
             await _repo.UpdateSystem(ctx.System.Id, new()
             {
                 WebhookUrl = newUrl,
-                Token = newToken,
+                WebhookToken = newToken,
             });
 
             await ctx.Reply($"{Emojis.Success} Successfully the new webhook URL for your system."
diff --git a/PluralKit.Core/Dispatch/DispatchModels.cs b/PluralKit.Core/Dispatch/DispatchModels.cs
index 543457d8..62ca8902 100644
--- a/PluralKit.Core/Dispatch/DispatchModels.cs
+++ b/PluralKit.Core/Dispatch/DispatchModels.cs
@@ -1,6 +1,8 @@
 using System;
+using System.Linq;
 using System.Net;
 using System.Net.Http;
+using System.Net.Sockets;
 using System.Threading.Tasks;
 
 using Newtonsoft.Json;
@@ -78,22 +80,24 @@ namespace PluralKit.Core
 
         public static async Task<bool> ValidateUri(string url)
         {
-            var uri = new Uri(url);
-
             IPHostEntry host = null;
 
             try
             {
+                var uri = new Uri(url);
                 host = await Dns.GetHostEntryAsync(uri.DnsSafeHost);
             }
-            catch (Exception) { }
+            catch (Exception)
+            {
+                return false;
+            }
 
             if (host == null || host.AddressList.Length == 0)
                 return false;
 
 #pragma warning disable CS0618
 
-            foreach (var address in host.AddressList)
+            foreach (var address in host.AddressList.Where(address => address.AddressFamily is AddressFamily.InterNetwork))
             {
                 if ((address.Address & 0x7f000000) == 0x7f000000) // 127.0/8
                     return false;
@@ -105,7 +109,11 @@ namespace PluralKit.Core
                     return false;
             }
 
-            return true;
+            if (host.AddressList.Any(address => address.IsIPv6LinkLocal))
+                return false;
+
+            // we only support IPv4 in prod :(
+            return host.AddressList.Any(address => address.AddressFamily is AddressFamily.InterNetwork);
         }
     }
 }
\ No newline at end of file