From ba8ccfeddcffd2a69e36392c04579c2b7e2a2fd4 Mon Sep 17 00:00:00 2001
From: Manu Nicolas <e.nicolas@criteo.com>
Date: Tue, 18 Aug 2026 17:24:48 +0000
Subject: [PATCH] CLEANUP: dns: centralize nameserver transport cleanup

Several resolver configuration error paths open-code nameserver
transport cleanup. They also assume that a nameserver owns either a
datagram transport or a stream transport, but never both.

Add dns_nameserver_deinit() and use it from these error paths. The
helper releases each transport's configuration-time allocations
independently and clears its pointer. No functional change is intended.
---
 include/haproxy/dns.h |  1 +
 src/dns.c             | 19 +++++++++++++++++++
 src/resolvers.c       | 28 ++++------------------------
 3 files changed, 24 insertions(+), 24 deletions(-)

diff --git a/include/haproxy/dns.h b/include/haproxy/dns.h
index 84181c43d..3e0cd5939 100644
--- a/include/haproxy/dns.h
+++ b/include/haproxy/dns.h
@@ -29,5 +29,6 @@ int dns_send_nameserver(struct dns_nameserver *ns, void *buf, size_t len);
 ssize_t dns_recv_nameserver(struct dns_nameserver *ns, void *data, size_t size);
 int dns_dgram_init(struct dns_nameserver *ns, struct sockaddr_storage *sk);
 int dns_stream_init(struct dns_nameserver *ns, struct server *s);
+void dns_nameserver_deinit(struct dns_nameserver *ns);
 
 #endif // _HAPROXY_DNS_H
diff --git a/src/dns.c b/src/dns.c
index 50f6e8ae0..53e71de0e 100644
--- a/src/dns.c
+++ b/src/dns.c
@@ -1417,6 +1417,25 @@ out:
 	return -1;
 }
 
+/* Releases transport allocations owned by <ns>. */
+void dns_nameserver_deinit(struct dns_nameserver *ns)
+{
+	if (ns->dgram) {
+		dns_ring_free(ns->dgram->ring_req);
+		free(ns->dgram);
+		ns->dgram = NULL;
+	}
+
+	if (ns->stream) {
+		dns_ring_free(ns->stream->ring_req);
+		task_destroy(ns->stream->task_req);
+		task_destroy(ns->stream->task_rsp);
+		task_destroy(ns->stream->task_idle);
+		free(ns->stream);
+		ns->stream = NULL;
+	}
+}
+
 int init_dns_buffers()
 {
 	dns_msg_trash = malloc(DNS_TCP_MSG_MAX_SIZE);
diff --git a/src/resolvers.c b/src/resolvers.c
index 65612ab92..06fb19c41 100644
--- a/src/resolvers.c
+++ b/src/resolvers.c
@@ -3590,8 +3590,7 @@ static int parse_resolve_conf(char **errmsg, char **warnmsg)
 			if (errmsg)
 				memprintf(errmsg, "parsing [/etc/resolv.conf:%d] : out of memory.", resolv_linenum);
 			err_code |= ERR_ALERT | ERR_FATAL;
-			dns_ring_free(newnameserver->dgram->ring_req);
-			free(newnameserver->dgram);
+			dns_nameserver_deinit(newnameserver);
 			free(newnameserver);
 			goto resolv_out;
 		}
@@ -3602,8 +3601,7 @@ static int parse_resolve_conf(char **errmsg, char **warnmsg)
 				memprintf(errmsg, "parsing [/etc/resolv.conf:%d] : out of memory.", resolv_linenum);
 			err_code |= ERR_ALERT | ERR_FATAL;
 			free((char *)newnameserver->conf.file);
-			dns_ring_free(newnameserver->dgram->ring_req);
-			free(newnameserver->dgram);
+			dns_nameserver_deinit(newnameserver);
 			free(newnameserver);
 			goto resolv_out;
 		}
@@ -3822,16 +3820,7 @@ int cfg_parse_resolvers(const char *file, int linenum, char **args, int kwm)
 		if ((newnameserver->conf.file = strdup(file)) == NULL) {
 			ha_alert("parsing [%s:%d] : out of memory.\n", file, linenum);
 			err_code |= ERR_ALERT | ERR_ABORT;
-			if (newnameserver->stream) {
-				dns_ring_free(newnameserver->stream->ring_req);
-				task_destroy(newnameserver->stream->task_req);
-				task_destroy(newnameserver->stream->task_rsp);
-				task_destroy(newnameserver->stream->task_idle);
-				free(newnameserver->stream);
-			} else if (newnameserver->dgram) {
-				dns_ring_free(newnameserver->dgram->ring_req);
-				free(newnameserver->dgram);
-			}
+			dns_nameserver_deinit(newnameserver);
 			free(newnameserver);
 			goto out;
 		}
@@ -3840,16 +3829,7 @@ int cfg_parse_resolvers(const char *file, int linenum, char **args, int kwm)
 			ha_alert("parsing [%s:%d] : out of memory.\n", file, linenum);
 			err_code |= ERR_ALERT | ERR_ABORT;
 			free((char *)newnameserver->conf.file);
-			if (newnameserver->stream) {
-				dns_ring_free(newnameserver->stream->ring_req);
-				task_destroy(newnameserver->stream->task_req);
-				task_destroy(newnameserver->stream->task_rsp);
-				task_destroy(newnameserver->stream->task_idle);
-				free(newnameserver->stream);
-			} else if (newnameserver->dgram) {
-				dns_ring_free(newnameserver->dgram->ring_req);
-				free(newnameserver->dgram);
-			}
+			dns_nameserver_deinit(newnameserver);
 			free(newnameserver);
 			goto out;
 		}
-- 
2.47.3