From 487d19a0b35b07a3ca2c0c5a53a44eb09ee21cb4 Mon Sep 17 00:00:00 2001
From: georglauterbach <44545919+georglauterbach@users.noreply.github.com>
Date: Sun, 13 Oct 2024 08:21:03 +0000
Subject: [PATCH 1/2] fix: do not query CNAME if A succeeded already

Signed-off-by: georglauterbach <44545919+georglauterbach@users.noreply.github.com>
---
 lib/private/Http/Client/DnsPinMiddleware.php   | 6 +++++-
 tests/lib/Http/Client/DnsPinMiddlewareTest.php | 5 +++--
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/lib/private/Http/Client/DnsPinMiddleware.php b/lib/private/Http/Client/DnsPinMiddleware.php
index 0d2f8d0bdc84c..95ad5641c55e8 100644
--- a/lib/private/Http/Client/DnsPinMiddleware.php
+++ b/lib/private/Http/Client/DnsPinMiddleware.php
@@ -74,17 +74,21 @@ private function dnsResolve(string $target, int $recursionCount) : array {
 
 		$soaDnsEntry = $this->soaRecord($target);
 		$dnsNegativeTtl = $soaDnsEntry['minimum-ttl'] ?? null;
+		$canHaveCnameRecord = true;
 
 		$dnsTypes = \defined('AF_INET6') || @inet_pton('::1')
 			? [DNS_A, DNS_AAAA, DNS_CNAME]
 			: [DNS_A, DNS_CNAME];
 		foreach ($dnsTypes as $dnsType) {
+			if ($canHaveCnameRecord === false && $dnsType === DNS_CNAME) {
+				continue;
+			}
+
 			if ($this->negativeDnsCache->isNegativeCached($target, $dnsType)) {
 				continue;
 			}
 
 			$dnsResponses = $this->dnsGetRecord($target, $dnsType);
-			$canHaveCnameRecord = true;
 			if ($dnsResponses !== false && count($dnsResponses) > 0) {
 				foreach ($dnsResponses as $dnsResponse) {
 					if (isset($dnsResponse['ip'])) {
diff --git a/tests/lib/Http/Client/DnsPinMiddlewareTest.php b/tests/lib/Http/Client/DnsPinMiddlewareTest.php
index 54071f37b1a82..6576302740821 100644
--- a/tests/lib/Http/Client/DnsPinMiddlewareTest.php
+++ b/tests/lib/Http/Client/DnsPinMiddlewareTest.php
@@ -554,10 +554,11 @@ static function (RequestInterface $request, array $options) {
 			['nextcloud' => ['allow_local_address' => false]]
 		);
 
-		$this->assertCount(4, $dnsQueries);
+		$this->assertCount(3, $dnsQueries);
 		$this->assertContains('example.com' . DNS_SOA, $dnsQueries);
 		$this->assertContains('subsubdomain.subdomain.example.com' . DNS_A, $dnsQueries);
 		$this->assertContains('subsubdomain.subdomain.example.com' . DNS_AAAA, $dnsQueries);
-		$this->assertContains('subsubdomain.subdomain.example.com' . DNS_CNAME, $dnsQueries);
+		// CNAME should not be queried if A or AAAA succeeded already
+		$this->assertNotContains('subsubdomain.subdomain.example.com' . DNS_CNAME, $dnsQueries);
 	}
 }

From c559f62a36403dbbee6bf56e28af536c5747d5f2 Mon Sep 17 00:00:00 2001
From: georglauterbach <44545919+georglauterbach@users.noreply.github.com>
Date: Thu, 7 Nov 2024 20:30:16 +0100
Subject: [PATCH 2/2] fix: remove superflous line

Signed-off-by: georglauterbach <44545919+georglauterbach@users.noreply.github.com>
---
 lib/private/Http/Client/DnsPinMiddleware.php | 1 -
 1 file changed, 1 deletion(-)

diff --git a/lib/private/Http/Client/DnsPinMiddleware.php b/lib/private/Http/Client/DnsPinMiddleware.php
index 95ad5641c55e8..1f2815990dcdc 100644
--- a/lib/private/Http/Client/DnsPinMiddleware.php
+++ b/lib/private/Http/Client/DnsPinMiddleware.php
@@ -99,7 +99,6 @@ private function dnsResolve(string $target, int $recursionCount) : array {
 						$canHaveCnameRecord = false;
 					} elseif (isset($dnsResponse['target']) && $canHaveCnameRecord) {
 						$targetIps = array_merge($targetIps, $this->dnsResolve($dnsResponse['target'], $recursionCount));
-						$canHaveCnameRecord = true;
 					}
 				}
 			} elseif ($dnsNegativeTtl !== null) {