[remote] Correctly handles Include directive in SSH config

cpasswords/remote.py

@@ -11,8 +11,10 @@ SPDX-License-Identifier: GPL-3.0-or-later
 import base64
 import json
 import logging
+import re
+from configparser import ConfigParser
 from functools import lru_cache
-from getpass import getpass
+from getpass import getpass, getuser
 from hashlib import sha1, sha256
 from pathlib import Path
 
@@ -117,12 +119,30 @@ def create_ssh_client(host, password=None):
     client.set_missing_host_key_policy(AskUserOrDNSPolicy)
 
     # Load config file and use the right username
-    try:
-        config = SSHConfig()
-        config.parse(Path.home().joinpath(".ssh/config").open())
-        username = config.lookup(host).get("user", None)
-    except FileNotFoundError:
-        username=None
+    # As of June 2020, paramiko doesn't support `Include` directive ...
+    # See https://github.com/paramiko/paramiko/issues/1609
+    config_path = Path.home().joinpath(".ssh/config")
+    # Match anything right after `Include` directive in a non commented line.
+    include_regex = re.compile("^(?!#).*(?<=Include )([^\s]+)")
+    config_files = [config_path]
+    with open(config_path) as cpath:
+        for line in cpath.readlines():
+            m = include_regex.match(line)
+            if m:
+                config_files.append(Path(m.group(1)))
+    username=None
+    for conf in config_files:
+        try:
+            config = SSHConfig()
+            config.parse(conf.expanduser().open())
+        except FileNotFoundError:
+            continue
+        username = config.lookup(host).get("user")
+        if username:
+            break
+    if not username:
+        username = getuser()
+    log.debug(f"Will connect to {host} as {username}")
 
     # Load system private keys
     client.load_system_host_keys()