From 56c88cafd1b3606e814069a79f4ec265fc427c87 Mon Sep 17 00:00:00 2001
From: James Falcon <james.falcon@canonical.com>
Date: Thu, 23 Mar 2023 10:21:56 -0500
Subject: [PATCH] Don't change permissions of netrules target (#2076)

Set permissions if file doesn't exist. Leave them if it does.

LP: #2011783

Co-authored-by: Chad Smith <chad.smith@canonical.com>
---
 cloudinit/net/eni.py                      |  4 +++-
 cloudinit/net/sysconfig.py                |  7 ++++++-
 tests/unittests/distros/test_netconfig.py | 20 ++++++++++++++++++--
 3 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/cloudinit/net/eni.py b/cloudinit/net/eni.py
index b0ec67b..f6398e3 100644
--- a/cloudinit/net/eni.py
+++ b/cloudinit/net/eni.py
@@ -571,7 +571,9 @@ class Renderer(renderer.Renderer):
             netrules = subp.target_path(target, self.netrules_path)
             util.ensure_dir(os.path.dirname(netrules))
             util.write_file(
-                netrules, self._render_persistent_net(network_state)
+                netrules,
+                content=self._render_persistent_net(network_state),
+                preserve_mode=True,
             )
 
 
diff --git a/cloudinit/net/sysconfig.py b/cloudinit/net/sysconfig.py
index 07f474d..d22354c 100644
--- a/cloudinit/net/sysconfig.py
+++ b/cloudinit/net/sysconfig.py
@@ -1008,7 +1008,12 @@ class Renderer(renderer.Renderer):
         if self.netrules_path:
             netrules_content = self._render_persistent_net(network_state)
             netrules_path = subp.target_path(target, self.netrules_path)
-            util.write_file(netrules_path, netrules_content, file_mode)
+            util.write_file(
+                netrules_path,
+                content=netrules_content,
+                mode=file_mode,
+                preserve_mode=True,
+            )
 
         sysconfig_path = subp.target_path(target, templates.get("control"))
         # Distros configuring /etc/sysconfig/network as a file e.g. Centos
diff --git a/tests/unittests/distros/test_netconfig.py b/tests/unittests/distros/test_netconfig.py
index a25be48..8760975 100644
--- a/tests/unittests/distros/test_netconfig.py
+++ b/tests/unittests/distros/test_netconfig.py
@@ -376,8 +376,16 @@ class TestNetCfgDistroUbuntuEni(TestNetCfgDistroBase):
     def eni_path(self):
         return "/etc/network/interfaces.d/50-cloud-init.cfg"
 
+    def rules_path(self):
+        return "/etc/udev/rules.d/70-persistent-net.rules"
+
     def _apply_and_verify_eni(
-        self, apply_fn, config, expected_cfgs=None, bringup=False
+        self,
+        apply_fn,
+        config,
+        expected_cfgs=None,
+        bringup=False,
+        previous_files=(),
     ):
         if not expected_cfgs:
             raise ValueError("expected_cfg must not be None")
@@ -385,7 +393,11 @@ class TestNetCfgDistroUbuntuEni(TestNetCfgDistroBase):
         tmpd = None
         with mock.patch("cloudinit.net.eni.available") as m_avail:
             m_avail.return_value = True
+            path_modes = {}
             with self.reRooted(tmpd) as tmpd:
+                for previous_path, content, mode in previous_files:
+                    util.write_file(previous_path, content, mode=mode)
+                    path_modes[previous_path] = mode
                 apply_fn(config, bringup)
 
         results = dir2dict(tmpd)
@@ -396,17 +408,21 @@ class TestNetCfgDistroUbuntuEni(TestNetCfgDistroBase):
             print(results[cfgpath])
             print("----------")
             self.assertEqual(expected, results[cfgpath])
-            self.assertEqual(0o644, get_mode(cfgpath, tmpd))
+            self.assertEqual(
+                path_modes.get(cfgpath, 0o644), get_mode(cfgpath, tmpd)
+            )
 
     def test_apply_network_config_eni_ub(self):
         expected_cfgs = {
             self.eni_path(): V1_NET_CFG_OUTPUT,
+            self.rules_path(): "",
         }
         # ub_distro.apply_network_config(V1_NET_CFG, False)
         self._apply_and_verify_eni(
             self.distro.apply_network_config,
             V1_NET_CFG,
             expected_cfgs=expected_cfgs.copy(),
+            previous_files=((self.rules_path(), "something", 0o660),),
         )
 
     def test_apply_network_config_ipv6_ub(self):
-- 
2.39.1