Fix X-Forwarded-For for IPv4 with dual stack sockets #2399 (#2400)

* Fix X-Forwarded-For for IPv4 with dual stack sockets #2399 * Address review feedback
microsoft · Feb 15, 2024 · d918126 · d918126
1 parent b12b34b
commit d918126
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Showing 2 changed files with 10 additions and 1 deletion.
diff --git a/src/ReverseProxy/Transforms/RequestHeaderXForwardedForTransform.cs b/src/ReverseProxy/Transforms/RequestHeaderXForwardedForTransform.cs
@@ -42,7 +42,14 @@ public override ValueTask ApplyAsync(RequestTransformContext context)
             throw new ArgumentNullException(nameof(context));
         }
 
-        var remoteIp = context.HttpContext.Connection.RemoteIpAddress?.ToString();
+        string? remoteIp = null;
+        var remoteIpAddress = context.HttpContext.Connection.RemoteIpAddress;
+        if (remoteIpAddress is not null)
+        {
+            remoteIp = remoteIpAddress.IsIPv4MappedToIPv6 ?
+                remoteIpAddress.MapToIPv4().ToString() :
+                remoteIpAddress.ToString();
+        }
 
         switch (TransformAction)
         {

diff --git a/test/ReverseProxy.Tests/Transforms/RequestHeaderXForwardedForTransformTests.cs b/test/ReverseProxy.Tests/Transforms/RequestHeaderXForwardedForTransformTests.cs
@@ -19,7 +19,9 @@ public class RequestHeaderXForwardedForTransformTests
     [InlineData("", "", ForwardedTransformActions.Remove, "")]
     [InlineData("", "::1", ForwardedTransformActions.Set, "::1")]
     [InlineData("", "127.0.0.1", ForwardedTransformActions.Set, "127.0.0.1")]
+    [InlineData("", "::ffff:127.0.0.1", ForwardedTransformActions.Set, "127.0.0.1")]
     [InlineData("", "127.0.0.1", ForwardedTransformActions.Append, "127.0.0.1")]
+    [InlineData("", "::ffff:127.0.0.1", ForwardedTransformActions.Append, "127.0.0.1")]
     [InlineData("", "127.0.0.1", ForwardedTransformActions.Remove, "")]
     [InlineData("existing,Header", "", ForwardedTransformActions.Set, "")]
     [InlineData("existing;Header", "", ForwardedTransformActions.Set, "")]