From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Mon, 17 Nov 2025 11:17:30 +0000 (+0100)
Subject: dnsdist: Better handling of XSK frames without any data
X-Git-Tag: rec-5.4.0-alpha1~22^2~5
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cbb214c47a3fcf10508a7b0439244fbcf11b8c74;p=thirdparty%2Fpdns.git

dnsdist: Better handling of XSK frames without any data

This might happen when we are creating a frame from scratch.

Signed-off-by: Remi Gacogne <remi.gacogne@powerdns.com>
---

diff --git a/pdns/dnsdistdist/xsk.cc b/pdns/dnsdistdist/xsk.cc
index 4411196594..6689335a28 100644
--- a/pdns/dnsdistdist/xsk.cc
+++ b/pdns/dnsdistdist/xsk.cc
@@ -551,6 +551,10 @@ XskSocket::XskUmem::~XskUmem()
 
 [[nodiscard]] size_t XskPacket::getDataSize() const noexcept
 {
+  const auto dataOffset = getDataOffset();
+  if (frameLength < dataOffset) {
+    return 0U;
+  }
   return frameLength - getDataOffset();
 }