From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Sat, 26 Oct 2019 16:47:49 +0000 (+0200)
Subject: dnsdist: Fix a race condition in the DOHUnit reference counter
X-Git-Tag: rec-4.3.0-alpha2~7^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=241ec94c60b4c2169938d7214d5ee7ac11f86576;p=thirdparty%2Fpdns.git

dnsdist: Fix a race condition in the DOHUnit reference counter

It was based on the reference counter used for the DOHAcceptContext
where thread safety was never an issue because those objects are
not shared between threads, but DOHUnit are.
---

diff --git a/pdns/dnsdistdist/doh.cc b/pdns/dnsdistdist/doh.cc
index 923f9eb816..9b29e650b8 100644
--- a/pdns/dnsdistdist/doh.cc
+++ b/pdns/dnsdistdist/doh.cc
@@ -75,8 +75,7 @@ public:
 
   void release()
   {
-    --d_refcnt;
-    if (d_refcnt == 0) {
+    if (--d_refcnt == 0) {
       SSL_CTX_free(d_h2o_accept_ctx.ssl_ctx);
       d_h2o_accept_ctx.ssl_ctx = nullptr;
       delete this;
diff --git a/pdns/doh.hh b/pdns/doh.hh
index 53cfbcd206..ba0499f7e0 100644
--- a/pdns/doh.hh
+++ b/pdns/doh.hh
@@ -151,8 +151,7 @@ struct DOHUnit
 
   void release()
   {
-    --d_refcnt;
-    if (d_refcnt == 0) {
+    if (--d_refcnt == 0) {
       delete this;
     }
   }