From: Ian Lance Taylor <iant@golang.org>
Date: Thu, 11 Apr 2024 21:36:25 +0000 (-0700)
Subject: [release-branch.go1.22] net: check SkipAdditional error result
X-Git-Tag: go1.22.3~4
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=93d8777d244962d1b706c0b695c8b72e9702577e;p=gostls13.git

[release-branch.go1.22] net: check SkipAdditional error result

This will avoid a potential endless loop for a corrupt DNS packet.

For #66754
Fixes #67040

Change-Id: I46591b3f7695bcc88d2312833e45955f8c129d2b
Reviewed-on: https://go-review.googlesource.com/c/go/+/578375
Reviewed-by: Damien Neil <dneil@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Commit-Queue: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
(cherry picked from commit ddfab21e464b9b4c15fe3dc97eb5d93a4932f434)
Reviewed-on: https://go-review.googlesource.com/c/go/+/581816
Reviewed-by: David Chase <drchase@google.com>
---

diff --git a/src/net/dnsclient_unix.go b/src/net/dnsclient_unix.go
index c291d5eb4f..8b3dd5371a 100644
--- a/src/net/dnsclient_unix.go
+++ b/src/net/dnsclient_unix.go
@@ -267,7 +267,9 @@ func extractExtendedRCode(p dnsmessage.Parser, hdr dnsmessage.Header) dnsmessage
 		if ahdr.Type == dnsmessage.TypeOPT {
 			return ahdr.ExtendedRCode(hdr.RCode)
 		}
-		p.SkipAdditional()
+		if err := p.SkipAdditional(); err != nil {
+			return hdr.RCode
+		}
 	}
 }