[libvirt] [PATCH] Use port range 5901-5999 if not set in qemu.conf, avoid port 5900

[Christophe de Dinechin]

In order to avoid conflict with the default port (5900) for host VNC server
(vino-server for example), or to conflict with X11 (starting at port 6000),
restrict range of ports to 5901-5999 unless explicitly specified in qemu.conf.

On the other hand, if port range is explicitly specified in qemu.conf,
there is no reason not to allow ports 1024-5900 (system ports are below 1024).

Addresses https://bugzilla.redhat.com/show_bug.cgi?id=1442235

Signed-off-by: Christophe de Dinechin <dinechin at redhat.com>
---
 src/qemu/qemu_conf.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
index 1b704da..07f3177 100644
--- a/src/qemu/qemu_conf.c
+++ b/src/qemu/qemu_conf.c
@@ -65,9 +65,15 @@ VIR_LOG_INIT("qemu.qemu_conf");
  * This limitation is mentioned in qemu.conf, so bear in mind that the
  * configuration file should reflect any changes made to these values.
  */
-#define QEMU_REMOTE_PORT_MIN 5900
+
+// Range of available ports - Avoid ports below 1024 (system ports)
+#define QEMU_REMOTE_PORT_MIN 1024
 #define QEMU_REMOTE_PORT_MAX 65535
 
+// Default min and max if not configured in qemu.conf
+#define QEMU_REMOTE_PORT_MIN_DEFAULT 5901
+#define QEMU_REMOTE_PORT_MAX_DEFAULT 5999
+
 #define QEMU_WEBSOCKET_PORT_MIN 5700
 #define QEMU_WEBSOCKET_PORT_MAX 65535
 
@@ -283,8 +289,8 @@ virQEMUDriverConfigPtr virQEMUDriverConfigNew(bool privileged)
 
 #undef SET_TLS_X509_CERT_DEFAULT
 
-    cfg->remotePortMin = QEMU_REMOTE_PORT_MIN;
-    cfg->remotePortMax = QEMU_REMOTE_PORT_MAX;
+    cfg->remotePortMin = QEMU_REMOTE_PORT_MIN_DEFAULT;
+    cfg->remotePortMax = QEMU_REMOTE_PORT_MAX_DEFAULT;
 
     cfg->webSocketPortMin = QEMU_WEBSOCKET_PORT_MIN;
     cfg->webSocketPortMax = QEMU_WEBSOCKET_PORT_MAX;
-- 
2.9.3