login: T5875: restore home directory permissions only when needed

This improves commit 3c990f49e ("login: T5875: restore home directory
permissions when re-adding user account") in a way that the home directory
owner is only altered if it differs from the expected owner.

Without this change on every boot we would alter the owner which could increase
the boot time if the home of a user is cluttered.

1 files changed, 6 insertions, 2 deletions

diff --git a/src/conf_mode/system_login.py b/src/conf_mode/system_login.py
index f34575aff..3d16bdb4a 100755
--- a/src/conf_mode/system_login.py
+++ b/src/conf_mode/system_login.py
@@ -20,6 +20,7 @@ from passlib.hosts import linux_context
 from psutil import users
 from pwd import getpwall
 from pwd import getpwnam
+from pwd import getpwuid
 from sys import exit
 from time import sleep
 
@@ -342,8 +343,11 @@ def apply(login):
                 # XXX: Should we deny using root at all?
                 home_dir = getpwnam(user).pw_dir
                 # T5875: ensure UID is properly set on home directory if user is re-added
-                if os.path.exists(home_dir):
-                    chown(home_dir, user=user, recursive=True)
+                # the home directory will always exist, as it's created above by --create-home,
+                # retrieve current owner of home directory and adjust it on demand
+                dir_owner = getpwuid(os.stat(home_dir).st_uid).pw_name
+                if dir_owner != user:
+                     chown(home_dir, user=user, recursive=True)
 
                 render(f'{home_dir}/.ssh/authorized_keys', 'login/authorized_keys.j2',
                        user_config, permission=0o600,