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ssh: Use privileged decorator for actions

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Tests:

- Functional tests work
- Updating SSH keys in user edit page sets the SSH keys. File is updated
  properly. Page shows newly set SSH keys.
  - Entering invalid auth credentials throws error
- Enabling/disabling SSH password authentication works.
  - Configuration file is updated.
  - App page shows proper value

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>
This commit is contained in:
Sunil Mohan Adapa 2022-08-26 14:14:57 -07:00 committed by James Valleroy
parent 8bdb73df9a
commit 12cf5065b0
No known key found for this signature in database
GPG Key ID: 77C0C75E7B650808
5 changed files with 51 additions and 121 deletions
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15
plinth/modules/ssh/__init__.py
View File

@ -1,7 +1,5 @@
# SPDX-License-Identifier: AGPL-3.0-or-later
"""
FreedomBox app for OpenSSH server.
"""
"""FreedomBox app for OpenSSH server."""
import pathlib
import re
@ -9,7 +7,6 @@ import subprocess
from django.utils.translation import gettext_lazy as _
from plinth import actions
from plinth import app as app_module
from plinth import menu
from plinth.daemon import Daemon
@ -17,7 +14,7 @@ from plinth.modules.backups.components import BackupRestore
from plinth.modules.firewall.components import Firewall
from plinth.package import Packages
from . import manifest
from . import manifest, privileged
_description = [
_('A Secure Shell server uses the secure shell protocol to accept '
@ -65,7 +62,7 @@ class SSHApp(app_module.App):
def setup(self, old_version):
"""Install and configure the app."""
super().setup(old_version)
actions.superuser_run('ssh', ['setup'])
privileged.setup()
self.enable()
@ -87,9 +84,3 @@ def get_host_keys():
host_keys.append(match.groupdict())
return host_keys
def is_password_authentication_disabled():
"""Return if ssh password authentication is enabled."""
return actions.superuser_run('ssh',
['get-password-config']).strip() == 'no'

106
actions/ssh → plinth/modules/ssh/privileged.py Executable file → Normal file
View File

@ -1,52 +1,20 @@
#!/usr/bin/python3
# SPDX-License-Identifier: AGPL-3.0-or-later
"""
Configuration helper for SSH server.
"""
"""Configuration helper for SSH server."""
import argparse
import grp
import os
import pwd
import shutil
import stat
import subprocess
import sys
import augeas
from plinth import action_utils, utils
from plinth.actions import privileged
def parse_arguments():
"""Return parsed command line arguments as dictionary."""
parser = argparse.ArgumentParser()
subparsers = parser.add_subparsers(dest='subcommand', help='Sub command')
subparsers.add_parser('setup', help='Setup SSH server')
get_keys = subparsers.add_parser('get-keys',
help='Get SSH authorized keys')
get_keys.add_argument('--username', required=True, type=_managed_user)
set_keys = subparsers.add_parser('set-keys',
help='Set SSH authorized keys')
set_keys.add_argument('--username', required=True, type=_managed_user)
set_keys.add_argument('--keys', required=True)
set_keys.add_argument('--auth-user', required=True)
subparsers.add_parser('get-password-config',
help='Get SSH password auth configuration')
set_password_config = subparsers.add_parser(
'set-password-config', help='Set SSH password auth configuration')
set_password_config.add_argument('--value')
subparsers.required = True
return parser.parse_args()
def _validate_user(username, must_be_admin=True):
def _validate_user(username, password, must_be_admin=True):
"""Validate a user."""
if must_be_admin:
try:
@ -55,29 +23,23 @@ def _validate_user(username, must_be_admin=True):
admins = []
if username not in admins:
msg = '"{}" is not authorized to perform this action'.format(
username)
raise argparse.ArgumentTypeError(msg)
msg = f'"{username}" is not authorized to perform this action'
raise PermissionError(msg)
password = _read_password()
if not utils.is_authenticated_user(username, password):
raise argparse.ArgumentTypeError("Invalid credentials")
raise PermissionError('Invalid credentials')
def _managed_user(username):
"""Raise an error if the user is root."""
if pwd.getpwnam(username).pw_gid == 0:
msg = 'User {} is not managed by FreedomBox'.format(username)
raise argparse.ArgumentTypeError(msg)
raise ValueError(f'User {username} is not managed by FreedomBox')
return username
def _read_password():
"""Read the password from stdin."""
return ''.join(sys.stdin)
def subcommand_setup(arguments):
@privileged
def setup():
"""Setup Open SSH server.
Regenerates deleted SSH keys. This is necessary when FreedomBox image is
@ -87,7 +49,6 @@ def subcommand_setup(arguments):
If the keys already exist, do nothing. This is necessary when a user
installs FreedomBox using an apt package. SSH keys exist and running
reconfigure on the openssh-server package does not regenerate them.
"""
action_utils.dpkg_reconfigure('openssh-server', {})
@ -97,29 +58,25 @@ def get_user_homedir(username):
try:
return pwd.getpwnam(username).pw_dir
except KeyError:
print('Username not found')
sys.exit(1)
raise ValueError('Username not found')
def subcommand_get_keys(arguments):
@privileged
def get_keys(user: str) -> str:
"""Get SSH authorized keys."""
user = arguments.username
path = os.path.join(get_user_homedir(user), '.ssh', 'authorized_keys')
try:
with open(path, 'r', encoding='utf-8') as file_handle:
print(file_handle.read())
return file_handle.read()
except FileNotFoundError:
pass
return ''
def subcommand_set_keys(arguments):
@privileged
def set_keys(user: str, keys: str, auth_user: str, auth_password: str):
"""Set SSH authorized keys."""
user = arguments.username
auth_user = arguments.auth_user
must_be_admin = user != auth_user
_validate_user(auth_user, must_be_admin=must_be_admin)
_validate_user(auth_user, auth_password, must_be_admin=must_be_admin)
ssh_folder = os.path.join(get_user_homedir(user), '.ssh')
key_file_path = os.path.join(ssh_folder, 'authorized_keys')
@ -131,7 +88,7 @@ def subcommand_set_keys(arguments):
shutil.chown(ssh_folder, user, 'users')
with open(key_file_path, 'w', encoding='utf-8') as file_handle:
file_handle.write(arguments.keys)
file_handle.write(keys)
shutil.chown(key_file_path, user, 'users')
os.chmod(key_file_path, stat.S_IRUSR | stat.S_IWUSR)
@ -148,30 +105,19 @@ def _load_augeas():
return aug
def subcommand_get_password_config(_):
@privileged
def is_password_authentication_enabled() -> bool:
"""Retrieve value of password authentication from sshd configuration."""
aug = _load_augeas()
field_path = '/files/etc/ssh/sshd_config/PasswordAuthentication'
get_value = aug.get(field_path)
print(get_value or 'yes')
return (get_value or 'yes') == 'yes'
def subcommand_set_password_config(arguments):
@privileged
def set_password_authentication(enable: bool):
"""Set value of password authentication in sshd configuration."""
value = 'yes' if enable else 'no'
aug = _load_augeas()
aug.set('/files/etc/ssh/sshd_config/PasswordAuthentication',
arguments.value)
aug.set('/files/etc/ssh/sshd_config/PasswordAuthentication', value)
aug.save()
def main():
"""Parse arguments and perform all duties."""
arguments = parse_arguments()
subcommand = arguments.subcommand.replace('-', '_')
subcommand_method = globals()['subcommand_' + subcommand]
subcommand_method(arguments)
if __name__ == '__main__':
main()

30
plinth/modules/ssh/views.py
View File

@ -1,7 +1,6 @@
# SPDX-License-Identifier: AGPL-3.0-or-later
"""
Views for the SSH module
"""
"""Views for the SSH app."""
from django.contrib import messages
from django.utils.translation import gettext_lazy as _
@ -9,32 +8,36 @@ from plinth import actions
from plinth.modules import ssh
from plinth.views import AppView
from . import is_password_authentication_disabled
from . import privileged
from .forms import SSHServerForm
class SshAppView(AppView):
"""Show ssh app main page."""
app_id = 'ssh'
template_name = 'ssh.html'
form_class = SSHServerForm
def get_context_data(self, *args, **kwargs):
"""Return additional context for rendering the template."""
context = super().get_context_data(**kwargs)
context['host_keys'] = ssh.get_host_keys()
return context
def get_initial(self):
"""Initial form value"""
"""Return initial values of the form."""
initial = super().get_initial()
initial.update({
'password_auth_disabled': is_password_authentication_disabled(),
'password_auth_disabled':
not privileged.is_password_authentication_enabled(),
})
return initial
def form_valid(self, form):
"""Apply changes from the form"""
"""Apply changes from the form."""
old_config = self.get_initial()
new_config = form.cleaned_data
@ -43,16 +46,9 @@ class SshAppView(AppView):
passwd_auth_changed = is_field_changed('password_auth_disabled')
if passwd_auth_changed:
if new_config['password_auth_disabled']:
passwd_auth = 'no'
message = _('SSH authentication with password disabled.')
else:
passwd_auth = 'yes'
message = _('SSH authentication with password enabled.')
actions.superuser_run(
'ssh', ['set-password-config', '--value', passwd_auth])
privileged.set_password_authentication(
not new_config['password_auth_disabled'])
actions.superuser_run('service', ['reload', 'ssh'])
messages.success(self.request, message)
messages.success(self.request, _('Configuration updated'))
return super().form_valid(form)

15
plinth/modules/users/forms.py
View File

@ -15,6 +15,7 @@ from django.utils.translation import gettext as _
from django.utils.translation import gettext_lazy
import plinth.forms
import plinth.modules.ssh.privileged as ssh_privileged
from plinth import actions
from plinth.errors import ActionError
from plinth.modules import first_boot
@ -294,16 +295,10 @@ class UserUpdateForm(ValidNewUsernameCheckMixin, PasswordConfirmForm,
_('Failed to add user to group.'))
try:
actions.superuser_run('ssh', [
'set-keys',
'--username',
user.get_username(),
'--keys',
self.cleaned_data['ssh_keys'].strip(),
'--auth-user',
auth_username,
], input=confirm_password.encode())
except ActionError:
ssh_privileged.set_keys(user.get_username(),
self.cleaned_data['ssh_keys'].strip(),
auth_username, confirm_password)
except Exception:
messages.error(self.request, _('Unable to set SSH keys.'))
is_active = self.cleaned_data['is_active']

6
plinth/modules/users/views.py
View File

@ -1,4 +1,5 @@
# SPDX-License-Identifier: AGPL-3.0-or-later
"""Django views for user app."""
import django.views.generic
from django.contrib import messages
@ -13,6 +14,7 @@ from django.utils.translation import gettext_lazy
from django.views.generic.edit import (CreateView, DeleteView, FormView,
UpdateView)
import plinth.modules.ssh.privileged as ssh_privileged
from plinth import actions, translation
from plinth.errors import ActionError
from plinth.modules import first_boot
@ -36,6 +38,7 @@ class ContextMixin:
class UserCreate(ContextMixin, SuccessMessageMixin, CreateView):
"""View to create a new user."""
form_class = CreateUserForm
template_name = 'users_create.html'
model = User
@ -95,8 +98,7 @@ class UserUpdate(ContextMixin, SuccessMessageMixin, UpdateView):
"""Return the data for initial form load."""
initial = super().get_initial()
try:
ssh_keys = actions.superuser_run(
'ssh', ['get-keys', '--username', self.object.username])
ssh_keys = ssh_privileged.get_keys(self.object.username)
initial['ssh_keys'] = ssh_keys.strip()
initial['language'] = self.object.userprofile.language
except ActionError: