Atomically move known hosts file into place for paramiko connections

Redo of original patch, which adds an additional check to ensure the
known_hosts file isn't trampled when host_key_checking is disabled.

Fixes #8169
This commit is contained in:
James Cammarata 2014-08-26 14:27:02 -05:00
parent ca7d8b6355
commit ed34cee36f

View file

@ -29,6 +29,7 @@ import pipes
import socket
import random
import logging
import tempfile
import traceback
import fcntl
import re
@ -363,7 +364,7 @@ class Connection(object):
if self.sftp is not None:
self.sftp.close()
if C.PARAMIKO_RECORD_HOST_KEYS and self._any_keys_added():
if C.HOST_KEY_CHECKING and C.PARAMIKO_RECORD_HOST_KEYS and self._any_keys_added():
# add any new SSH host keys -- warning -- this could be slow
lockfile = self.keyfile.replace("known_hosts",".known_hosts.lock")
@ -379,7 +380,25 @@ 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: