From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Wed, 8 Dec 2021 14:36:37 +0000 (+0100)
Subject: dnsdist: Check the size of the query when re-sending a DoH query
X-Git-Tag: auth-4.7.0-alpha1~112^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5d552300959a5133546bb65ddeb8ce918d598c08;p=thirdparty%2Fpdns.git

dnsdist: Check the size of the query when re-sending a DoH query

When the UDP response to a DoH query was truncated, we re-send the
query via TCP, passing it to a TCP worker. We need to edit the ID
to its original value before that, and while there is no reason
that the query is smaller than a dnsheader, we need to check its size,
not the size of the response.
---

diff --git a/pdns/dnsdistdist/doh.cc b/pdns/dnsdistdist/doh.cc
index 3bfd66a008..268e6f97d3 100644
--- a/pdns/dnsdistdist/doh.cc
+++ b/pdns/dnsdistdist/doh.cc
@@ -1320,7 +1320,7 @@ static void on_dnsdist(h2o_socket_t *listener, const char *err)
       continue;
     }
 
-    if (!du->tcp && du->truncated && du->response.size() > sizeof(dnsheader)) {
+    if (!du->tcp && du->truncated && du->query.size() > sizeof(dnsheader)) {
       /* restoring the original ID */
       dnsheader* queryDH = reinterpret_cast<struct dnsheader*>(du->query.data() + du->proxyProtocolPayloadSize);
       queryDH->id = du->ids.origID;