Atomically move known hosts file into place when edited by paramiko connections

Fixes #8169

lib/ansible/runner/connection_plugins/paramiko_ssh.py

@@ -29,6 +29,7 @@ import pipes
 import socket
 import random
 import logging
+import tempfile
 import traceback
 import fcntl
 import re
@@ -39,7 +40,6 @@ from ansible.callbacks import vvv
 from ansible import errors
 from ansible import utils
 from ansible import constants as C
-from ansible.module_utils.basic import atomic_move
             
 AUTHENTICITY_MSG="""
 paramiko: The authenticity of host '%s' can't be established. 
@@ -381,7 +381,25 @@ class Connection(object):
 
                 self.ssh.load_system_host_keys()
                 self.ssh._host_keys.update(self.ssh._system_host_keys)
-                self._save_ssh_host_keys(self.keyfile)
+
+                # gather information about the current key file, so
+                # we can ensure the new file has the correct mode/owner
+
+                key_dir  = os.path.dirname(self.keyfile)
+                key_stat = os.stat(self.keyfile)
+
+                # Save the new keys to a temporary file and move it into place
+                # rather than rewriting the file. We set delete=False because
+                # the file will be moved into place rather than cleaned up.
+
+                tmp_keyfile = tempfile.NamedTemporaryFile(dir=key_dir, delete=False)
+                os.chmod(tmp_keyfile.name, key_stat.st_mode & 07777)
+                os.chown(tmp_keyfile.name, key_stat.st_uid, key_stat.st_gid)
+
+                self._save_ssh_host_keys(tmp_keyfile.name)
+                tmp_keyfile.close()
+
+                os.rename(tmp_keyfile.name, self.keyfile)
 
             except: