T5474: establish common file name pattern for XML conf mode commands

We will use _ as CLI level divider. The XML definition filename and also
the Python helper should match the CLI node.

Example:
set interfaces ethernet -> interfaces_ethernet.xml.in
set interfaces bond -> interfaces_bond.xml.in
set service dhcp-server -> service_dhcp-server-xml.in

1 files changed, 423 insertions, 0 deletions

diff --git a/src/conf_mode/system_login.py b/src/conf_mode/system_login.py
new file mode 100755
index 000000000..f34575aff
--- /dev/null
+++ b/src/conf_mode/system_login.py
@@ -0,0 +1,423 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2020-2023 VyOS maintainers and contributors
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 or later as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+
+from passlib.hosts import linux_context
+from psutil import users
+from pwd import getpwall
+from pwd import getpwnam
+from sys import exit
+from time import sleep
+
+from vyos.config import Config
+from vyos.configverify import verify_vrf
+from vyos.defaults import directories
+from vyos.template import render
+from vyos.template import is_ipv4
+from vyos.utils.dict import dict_search
+from vyos.utils.file import chown
+from vyos.utils.process import cmd
+from vyos.utils.process import call
+from vyos.utils.process import rc_cmd
+from vyos.utils.process import run
+from vyos.utils.process import DEVNULL
+from vyos import ConfigError
+from vyos import airbag
+airbag.enable()
+
+autologout_file = "/etc/profile.d/autologout.sh"
+limits_file = "/etc/security/limits.d/10-vyos.conf"
+radius_config_file = "/etc/pam_radius_auth.conf"
+tacacs_pam_config_file = "/etc/tacplus_servers"
+tacacs_nss_config_file = "/etc/tacplus_nss.conf"
+nss_config_file = "/etc/nsswitch.conf"
+
+# Minimum UID used when adding system users
+MIN_USER_UID: int = 1000
+# Maximim UID used when adding system users
+MAX_USER_UID: int = 59999
+# LOGIN_TIMEOUT from /etc/loign.defs minus 10 sec
+MAX_RADIUS_TIMEOUT: int = 50
+# MAX_RADIUS_TIMEOUT divided by 2 sec (minimum recomended timeout)
+MAX_RADIUS_COUNT: int = 8
+# Maximum number of supported TACACS servers
+MAX_TACACS_COUNT: int = 8
+
+# List of local user accounts that must be preserved
+SYSTEM_USER_SKIP_LIST: list = ['radius_user', 'radius_priv_user', 'tacacs0', 'tacacs1',
+                              'tacacs2', 'tacacs3', 'tacacs4', 'tacacs5', 'tacacs6',
+                              'tacacs7', 'tacacs8', 'tacacs9', 'tacacs10',' tacacs11',
+                              'tacacs12', 'tacacs13', 'tacacs14', 'tacacs15']
+
+def get_local_users():
+    """Return list of dynamically allocated users (see Debian Policy Manual)"""
+    local_users = []
+    for s_user in getpwall():
+        if getpwnam(s_user.pw_name).pw_uid < MIN_USER_UID:
+            continue
+        if getpwnam(s_user.pw_name).pw_uid > MAX_USER_UID:
+            continue
+        if s_user.pw_name in SYSTEM_USER_SKIP_LIST:
+            continue
+        local_users.append(s_user.pw_name)
+
+    return local_users
+
+def get_shadow_password(username):
+    with open('/etc/shadow') as f:
+        for user in f.readlines():
+            items = user.split(":")
+            if username == items[0]:
+                return items[1]
+    return None
+
+def get_config(config=None):
+    if config:
+        conf = config
+    else:
+        conf = Config()
+    base = ['system', 'login']
+    login = conf.get_config_dict(base, key_mangling=('-', '_'),
+                                 no_tag_node_value_mangle=True,
+                                 get_first_key=True,
+                                 with_recursive_defaults=True)
+
+    # users no longer existing in the running configuration need to be deleted
+    local_users = get_local_users()
+    cli_users = []
+    if 'user' in login:
+        cli_users = list(login['user'])
+
+    # prune TACACS global defaults if not set by user
+    if login.from_defaults(['tacacs']):
+        del login['tacacs']
+    # same for RADIUS
+    if login.from_defaults(['radius']):
+        del login['radius']
+
+    # create a list of all users, cli and users
+    all_users = list(set(local_users + cli_users))
+    # We will remove any normal users that dos not exist in the current
+    # configuration. This can happen if user is added but configuration was not
+    # saved and system is rebooted.
+    rm_users = [tmp for tmp in all_users if tmp not in cli_users]
+    if rm_users: login.update({'rm_users' : rm_users})
+
+    return login
+
+def verify(login):
+    if 'rm_users' in login:
+        # This check is required as the script is also executed from vyos-router
+        # init script and there is no SUDO_USER environment variable available
+        # during system boot.
+        if 'SUDO_USER' in os.environ:
+            cur_user = os.environ['SUDO_USER']
+            if cur_user in login['rm_users']:
+                raise ConfigError(f'Attempting to delete current user: {cur_user}')
+
+    if 'user' in login:
+        system_users = getpwall()
+        for user, user_config in login['user'].items():
+            # Linux system users range up until UID 1000, we can not create a
+            # VyOS CLI user which already exists as system user
+            for s_user in system_users:
+                if s_user.pw_name == user and s_user.pw_uid < MIN_USER_UID:
+                    raise ConfigError(f'User "{user}" can not be created, conflict with local system account!')
+
+            for pubkey, pubkey_options in (dict_search('authentication.public_keys', user_config) or {}).items():
+                if 'type' not in pubkey_options:
+                    raise ConfigError(f'Missing type for public-key "{pubkey}"!')
+                if 'key' not in pubkey_options:
+                    raise ConfigError(f'Missing key for public-key "{pubkey}"!')
+
+    if {'radius', 'tacacs'} <= set(login):
+        raise ConfigError('Using both RADIUS and TACACS at the same time is not supported!')
+
+    # At lease one RADIUS server must not be disabled
+    if 'radius' in login:
+        if 'server' not in login['radius']:
+            raise ConfigError('No RADIUS server defined!')
+        sum_timeout: int = 0
+        radius_servers_count: int = 0
+        fail = True
+        for server, server_config in dict_search('radius.server', login).items():
+            if 'key' not in server_config:
+                raise ConfigError(f'RADIUS server "{server}" requires key!')
+            if 'disable' not in server_config:
+                sum_timeout += int(server_config['timeout'])
+                radius_servers_count += 1
+                fail = False
+
+        if fail:
+            raise ConfigError('All RADIUS servers are disabled')
+
+        if radius_servers_count > MAX_RADIUS_COUNT:
+            raise ConfigError(f'Number of RADIUS servers exceeded maximum of {MAX_RADIUS_COUNT}!')
+
+        if sum_timeout > MAX_RADIUS_TIMEOUT:
+            raise ConfigError('Sum of RADIUS servers timeouts '
+                              'has to be less or eq 50 sec')
+
+        verify_vrf(login['radius'])
+
+        if 'source_address' in login['radius']:
+            ipv4_count = 0
+            ipv6_count = 0
+            for address in login['radius']['source_address']:
+                if is_ipv4(address): ipv4_count += 1
+                else:                ipv6_count += 1
+
+            if ipv4_count > 1:
+                raise ConfigError('Only one IPv4 source-address can be set!')
+            if ipv6_count > 1:
+                raise ConfigError('Only one IPv6 source-address can be set!')
+
+    if 'tacacs' in login:
+        tacacs_servers_count: int = 0
+        fail = True
+        for server, server_config in dict_search('tacacs.server', login).items():
+            if 'key' not in server_config:
+                raise ConfigError(f'TACACS server "{server}" requires key!')
+            if 'disable' not in server_config:
+                tacacs_servers_count += 1
+                fail = False
+
+        if fail:
+            raise ConfigError('All RADIUS servers are disabled')
+
+        if tacacs_servers_count > MAX_TACACS_COUNT:
+            raise ConfigError(f'Number of TACACS servers exceeded maximum of {MAX_TACACS_COUNT}!')
+
+        verify_vrf(login['tacacs'])
+
+    if 'max_login_session' in login and 'timeout' not in login:
+        raise ConfigError('"login timeout" must be configured!')
+
+    return None
+
+
+def generate(login):
+    # calculate users encrypted password
+    if 'user' in login:
+        for user, user_config in login['user'].items():
+            tmp = dict_search('authentication.plaintext_password', user_config)
+            if tmp:
+                encrypted_password = linux_context.hash(tmp)
+                login['user'][user]['authentication']['encrypted_password'] = encrypted_password
+                del login['user'][user]['authentication']['plaintext_password']
+
+                # remove old plaintext password and set new encrypted password
+                env = os.environ.copy()
+                env['vyos_libexec_dir'] = directories['base']
+
+                # Set default commands for re-adding user with encrypted password
+                del_user_plain = f"system login user {user} authentication plaintext-password"
+                add_user_encrypt = f"system login user {user} authentication encrypted-password '{encrypted_password}'"
+
+                lvl = env['VYATTA_EDIT_LEVEL']
+                # We're in config edit level, for example "edit system login"
+                # Change default commands for re-adding user with encrypted password
+                if lvl != '/':
+                    # Replace '/system/login' to 'system login'
+                    lvl = lvl.strip('/').split('/')
+                    # Convert command str to list
+                    del_user_plain = del_user_plain.split()
+                    # New command exclude level, for example "edit system login"
+                    del_user_plain = del_user_plain[len(lvl):]
+                    # Convert string to list
+                    del_user_plain = " ".join(del_user_plain)
+
+                    add_user_encrypt = add_user_encrypt.split()
+                    add_user_encrypt = add_user_encrypt[len(lvl):]
+                    add_user_encrypt = " ".join(add_user_encrypt)
+
+                ret, out = rc_cmd(f"/opt/vyatta/sbin/my_delete {del_user_plain}", env=env)
+                if ret: raise ConfigError(out)
+                ret, out = rc_cmd(f"/opt/vyatta/sbin/my_set {add_user_encrypt}", env=env)
+                if ret: raise ConfigError(out)
+            else:
+                try:
+                    if get_shadow_password(user) == dict_search('authentication.encrypted_password', user_config):
+                        # If the current encrypted bassword matches the encrypted password
+                        # from the config - do not update it. This will remove the encrypted
+                        # value from the system logs.
+                        #
+                        # The encrypted password will be set only once during the first boot
+                        # after an image upgrade.
+                        del login['user'][user]['authentication']['encrypted_password']
+                except:
+                    pass
+
+    ### RADIUS based user authentication
+    if 'radius' in login:
+        render(radius_config_file, 'login/pam_radius_auth.conf.j2', login,
+                   permission=0o600, user='root', group='root')
+    else:
+        if os.path.isfile(radius_config_file):
+            os.unlink(radius_config_file)
+
+    ### TACACS+ based user authentication
+    if 'tacacs' in login:
+        render(tacacs_pam_config_file, 'login/tacplus_servers.j2', login,
+                   permission=0o644, user='root', group='root')
+        render(tacacs_nss_config_file, 'login/tacplus_nss.conf.j2', login,
+                   permission=0o644, user='root', group='root')
+    else:
+        if os.path.isfile(tacacs_pam_config_file):
+            os.unlink(tacacs_pam_config_file)
+        if os.path.isfile(tacacs_nss_config_file):
+            os.unlink(tacacs_nss_config_file)
+
+
+
+    # NSS must always be present on the system
+    render(nss_config_file, 'login/nsswitch.conf.j2', login,
+               permission=0o644, user='root', group='root')
+
+    # /etc/security/limits.d/10-vyos.conf
+    if 'max_login_session' in login:
+        render(limits_file, 'login/limits.j2', login,
+                   permission=0o644, user='root', group='root')
+    else:
+        if os.path.isfile(limits_file):
+            os.unlink(limits_file)
+
+    if 'timeout' in login:
+        render(autologout_file, 'login/autologout.j2', login,
+                   permission=0o755, user='root', group='root')
+    else:
+        if os.path.isfile(autologout_file):
+            os.unlink(autologout_file)
+
+    return None
+
+
+def apply(login):
+    enable_otp = False
+    if 'user' in login:
+        for user, user_config in login['user'].items():
+            # make new user using vyatta shell and make home directory (-m),
+            # default group of 100 (users)
+            command = 'useradd --create-home --no-user-group '
+            # check if user already exists:
+            if user in get_local_users():
+                # update existing account
+                command = 'usermod'
+
+            # all accounts use /bin/vbash
+            command += ' --shell /bin/vbash'
+            # we need to use '' quotes when passing formatted data to the shell
+            # else it will not work as some data parts are lost in translation
+            tmp = dict_search('authentication.encrypted_password', user_config)
+            if tmp: command += f" --password '{tmp}'"
+
+            tmp = dict_search('full_name', user_config)
+            if tmp: command += f" --comment '{tmp}'"
+
+            tmp = dict_search('home_directory', user_config)
+            if tmp: command += f" --home '{tmp}'"
+            else: command += f" --home '/home/{user}'"
+
+            command += f' --groups frr,frrvty,vyattacfg,sudo,adm,dip,disk,_kea {user}'
+            try:
+                cmd(command)
+                # we should not rely on the value stored in
+                # user_config['home_directory'], as a crazy user will choose
+                # username root or any other system user which will fail.
+                #
+                # 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)
+
+                render(f'{home_dir}/.ssh/authorized_keys', 'login/authorized_keys.j2',
+                       user_config, permission=0o600,
+                       formater=lambda _: _.replace("&quot;", '"'),
+                       user=user, group='users')
+
+            except Exception as e:
+                raise ConfigError(f'Adding user "{user}" raised exception: "{e}"')
+
+            # Generate 2FA/MFA One-Time-Pad configuration
+            if dict_search('authentication.otp.key', user_config):
+                enable_otp = True
+                render(f'{home_dir}/.google_authenticator', 'login/pam_otp_ga.conf.j2',
+                       user_config, permission=0o400, user=user, group='users')
+            else:
+                # delete configuration as it's not enabled for the user
+                if os.path.exists(f'{home_dir}/.google_authenticator'):
+                    os.remove(f'{home_dir}/.google_authenticator')
+
+    if 'rm_users' in login:
+        for user in login['rm_users']:
+            try:
+                # Disable user to prevent re-login
+                call(f'usermod -s /sbin/nologin {user}')
+
+                # Logout user if he is still logged in
+                if user in list(set([tmp[0] for tmp in users()])):
+                    print(f'{user} is logged in, forcing logout!')
+                    # re-run command until user is logged out
+                    while run(f'pkill -HUP -u {user}'):
+                        sleep(0.250)
+
+                # Remove user account but leave home directory in place. Re-run
+                # command until user is removed - userdel might return 8 as
+                # SSH sessions are not all yet properly cleaned away, thus we
+                # simply re-run the command until the account wen't away
+                while run(f'userdel {user}', stderr=DEVNULL):
+                    sleep(0.250)
+
+            except Exception as e:
+                raise ConfigError(f'Deleting user "{user}" raised exception: {e}')
+
+    # Enable/disable RADIUS in PAM configuration
+    cmd('pam-auth-update --disable radius-mandatory radius-optional')
+    if 'radius' in login:
+        if login['radius'].get('security_mode', '') == 'mandatory':
+            pam_profile = 'radius-mandatory'
+        else:
+            pam_profile = 'radius-optional'
+        cmd(f'pam-auth-update --enable {pam_profile}')
+
+    # Enable/disable TACACS+ in PAM configuration
+    cmd('pam-auth-update --disable tacplus-mandatory tacplus-optional')
+    if 'tacacs' in login:
+        if login['tacacs'].get('security_mode', '') == 'mandatory':
+            pam_profile = 'tacplus-mandatory'
+        else:
+            pam_profile = 'tacplus-optional'
+        cmd(f'pam-auth-update --enable {pam_profile}')
+
+    # Enable/disable Google authenticator
+    cmd('pam-auth-update --disable mfa-google-authenticator')
+    if enable_otp:
+        cmd(f'pam-auth-update --enable mfa-google-authenticator')
+
+    return None
+
+
+if __name__ == '__main__':
+    try:
+        c = get_config()
+        verify(c)
+        generate(c)
+        apply(c)
+    except ConfigError as e:
+        print(e)
+        exit(1)