From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Fri, 5 Sep 2025 07:35:44 +0000 (+0200)
Subject: dnsdist: Fix the IO reentry guard in outgoing DoH
X-Git-Tag: dnsdist-2.0.1~1^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=db3433c1a3adacb4d434ec06f63fc440a5aa29c3;p=thirdparty%2Fpdns.git

dnsdist: Fix the IO reentry guard in outgoing DoH

Signed-off-by: Remi Gacogne <remi.gacogne@powerdns.com>
(cherry picked from commit 81f0706bdf91c01ee26f8bb18315206af7a70b31)
---

diff --git a/pdns/dnsdistdist/dnsdist-nghttp2.cc b/pdns/dnsdistdist/dnsdist-nghttp2.cc
index 624d0f121..75b1843c2 100644
--- a/pdns/dnsdistdist/dnsdist-nghttp2.cc
+++ b/pdns/dnsdistdist/dnsdist-nghttp2.cc
@@ -376,6 +376,10 @@ void DoHConnectionToBackend::handleReadableIOCallback(int fd, FDMultiplexer::fun
     throw std::runtime_error("Unexpected socket descriptor " + std::to_string(fd) + " received in " + std::string(__PRETTY_FUNCTION__) + ", expected " + std::to_string(conn->getHandle()));
   }
 
+  if (conn->d_inIOCallback) {
+    return;
+  }
+  conn->d_inIOCallback = true;
   dnsdist::tcp::HandlingIOGuard handlingIOGuard(conn->d_inIOCallback);
   IOStateGuard ioGuard(conn->d_ioState);
   do {