[PATCH dpdk] telemetry-exporter: listen on loopback by default

[Robin Jarry <rjarry@redhat.com>]

Fix the following warning reported by Coverity:

Defect type: SIGMA.insecure_network_bind:
> dpdk-stable-24.11.1/usertools/dpdk-telemetry-exporter.py:278:
> Sigma main event: The HTTP server binds to all network interfaces by
> setting the IP address to "", `0.0.0.0`, `::`, or `::0`.
> This may expose the server to unintended traffic.

Avoid listening to all interfaces by default to avoid exposing private
information unwillingly.

Unrelated: The Python stdlib TCP server listens on IPv4 only by default.
Changing this requires creating a subclass that overrides address_family
to socket.AF_INET6.

Fixes: d94ebd627a86 ("usertools: add telemetry exporter")
Cc: stable@dpdk.org
Signed-off-by: Robin Jarry <rjarry@redhat.com>
---
 usertools/dpdk-telemetry-exporter.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/usertools/dpdk-telemetry-exporter.py b/usertools/dpdk-telemetry-exporter.py
index 6eca0db2e80a..6f66d4ecaab1 100755
--- a/usertools/dpdk-telemetry-exporter.py
+++ b/usertools/dpdk-telemetry-exporter.py
@@ -75,7 +75,7 @@ def cmd(self, uri, arg=None) -> dict | list:
     "/usr/local/share/dpdk/telemetry-endpoints",
     "/usr/share/dpdk/telemetry-endpoints",
 ]
-DEFAULT_OUTPUT = "openmetrics://:9876"
+DEFAULT_OUTPUT = "openmetrics://127.0.0.1:9876"
 
 
 def main():
@@ -275,11 +275,11 @@ def serve_openmetrics(
     Start an HTTP server and serve requests in the openmetrics/prometheus
     format.
     """
-    listen = (args.output.hostname or "", int(args.output.port or 80))
+    listen = (args.output.hostname or "127.0.0.1", int(args.output.port or 80))
     with server.HTTPServer(listen, OpenmetricsHandler) as httpd:
         httpd.dpdk_socket_path = args.socket_path
         httpd.telemetry_endpoints = endpoints
-        LOG.info("listening on port %s", httpd.server_port)
+        LOG.info("listening on %s", httpd.socket.getsockname())
         try:
             httpd.serve_forever()
         except KeyboardInterrupt:
-- 
2.48.1