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# Copyright 2016 Canonical Limited.
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# This file is part of charm-helpers.
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# charm-helpers is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Lesser General Public License version 3 as
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# published by the Free Software Foundation.
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# charm-helpers is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Lesser General Public License for more details.
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# You should have received a copy of the GNU Lesser General Public License
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# along with charm-helpers. If not, see <http://www.gnu.org/licenses/>.
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from charmhelpers.core.hookenv import (
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from charmhelpers.contrib.hardening import utils
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from charmhelpers.contrib.hardening.audits.file import (
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from charmhelpers.contrib.hardening.host import TEMPLATES_DIR
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SYSCTL_DEFAULTS = """net.ipv4.ip_forward=%(net_ipv4_ip_forward)s
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net.ipv6.conf.all.forwarding=%(net_ipv6_conf_all_forwarding)s
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net.ipv4.conf.all.rp_filter=1
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net.ipv4.conf.default.rp_filter=1
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net.ipv4.icmp_echo_ignore_broadcasts=1
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net.ipv4.icmp_ignore_bogus_error_responses=1
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net.ipv4.icmp_ratelimit=100
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net.ipv4.icmp_ratemask=88089
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net.ipv6.conf.all.disable_ipv6=%(net_ipv6_conf_all_disable_ipv6)s
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net.ipv4.tcp_timestamps=%(net_ipv4_tcp_timestamps)s
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net.ipv4.conf.all.arp_ignore=%(net_ipv4_conf_all_arp_ignore)s
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net.ipv4.conf.all.arp_announce=%(net_ipv4_conf_all_arp_announce)s
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net.ipv4.tcp_rfc1337=1
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net.ipv4.tcp_syncookies=1
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net.ipv4.conf.all.shared_media=1
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net.ipv4.conf.default.shared_media=1
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net.ipv4.conf.all.accept_source_route=0
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net.ipv4.conf.default.accept_source_route=0
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net.ipv4.conf.all.accept_redirects=0
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net.ipv4.conf.default.accept_redirects=0
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net.ipv6.conf.all.accept_redirects=0
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net.ipv6.conf.default.accept_redirects=0
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net.ipv4.conf.all.secure_redirects=0
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net.ipv4.conf.default.secure_redirects=0
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net.ipv4.conf.all.send_redirects=0
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net.ipv4.conf.default.send_redirects=0
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net.ipv4.conf.all.log_martians=0
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net.ipv6.conf.default.router_solicitations=0
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net.ipv6.conf.default.accept_ra_rtr_pref=0
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net.ipv6.conf.default.accept_ra_pinfo=0
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net.ipv6.conf.default.accept_ra_defrtr=0
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net.ipv6.conf.default.autoconf=0
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net.ipv6.conf.default.dad_transmits=0
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net.ipv6.conf.default.max_addresses=1
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net.ipv6.conf.all.accept_ra=0
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net.ipv6.conf.default.accept_ra=0
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kernel.modules_disabled=%(kernel_modules_disabled)s
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kernel.sysrq=%(kernel_sysrq)s
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fs.suid_dumpable=%(fs_suid_dumpable)s
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kernel.randomize_va_space=2
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"""Get OS hardening sysctl audits.
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:returns: dictionary of audits
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settings = utils.get_settings('os')
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# Apply the sysctl settings which are configured to be applied.
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audits.append(SysctlConf())
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# Make sure that only root has access to the sysctl.conf file, and
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# that it is read-only.
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audits.append(FilePermissionAudit('/etc/sysctl.conf',
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group='root', mode=0o0440))
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# If module loading is not enabled, then ensure that the modules
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# file has the appropriate permissions and rebuild the initramfs
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if not settings['security']['kernel_enable_module_loading']:
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audits.append(ModulesTemplate())
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class ModulesContext(object):
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settings = utils.get_settings('os')
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with open('/proc/cpuinfo', 'r') as fd:
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cpuinfo = fd.readlines()
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match = re.search(r"^vendor_id\s+:\s+(.+)", line)
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vendor = match.group(1)
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if vendor == "GenuineIntel":
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elif vendor == "AuthenticAMD":
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ctxt = {'arch': platform.processor(),
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'desktop_enable': settings['general']['desktop_enable']}
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class ModulesTemplate(object):
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super(ModulesTemplate, self).__init__('/etc/initramfs-tools/modules',
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templates_dir=TEMPLATES_DIR,
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user='root', group='root',
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def post_write(self):
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subprocess.check_call(['update-initramfs', '-u'])
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class SysCtlHardeningContext(object):
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settings = utils.get_settings('os')
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ctxt = {'sysctl': {}}
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log("Applying sysctl settings", level=INFO)
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extras = {'net_ipv4_ip_forward': 0,
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'net_ipv6_conf_all_forwarding': 0,
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'net_ipv6_conf_all_disable_ipv6': 1,
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'net_ipv4_tcp_timestamps': 0,
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'net_ipv4_conf_all_arp_ignore': 0,
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'net_ipv4_conf_all_arp_announce': 0,
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'fs_suid_dumpable': 0,
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'kernel_modules_disabled': 1}
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if settings['sysctl']['ipv6_enable']:
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extras['net_ipv6_conf_all_disable_ipv6'] = 0
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if settings['sysctl']['forwarding']:
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extras['net_ipv4_ip_forward'] = 1
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extras['net_ipv6_conf_all_forwarding'] = 1
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if settings['sysctl']['arp_restricted']:
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extras['net_ipv4_conf_all_arp_ignore'] = 1
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extras['net_ipv4_conf_all_arp_announce'] = 2
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if settings['security']['kernel_enable_module_loading']:
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extras['kernel_modules_disabled'] = 0
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if settings['sysctl']['kernel_enable_sysrq']:
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sysrq_val = settings['sysctl']['kernel_secure_sysrq']
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extras['kernel_sysrq'] = sysrq_val
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if settings['security']['kernel_enable_core_dump']:
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extras['fs_suid_dumpable'] = 1
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settings.update(extras)
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for d in (SYSCTL_DEFAULTS % settings).split():
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d = d.strip().partition('=')
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path = os.path.join('/proc/sys', key.replace('.', '/'))
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if not os.path.exists(path):
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log("Skipping '%s' since '%s' does not exist" % (key, path),
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ctxt['sysctl'][key] = d[2] or None
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# Translate for python3
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return {'sysctl_settings':
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[(k, v) for k, v in six.iteritems(ctxt['sysctl'])]}
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class SysctlConf(TemplatedFile):
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"""An audit check for sysctl settings."""
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self.conffile = '/etc/sysctl.d/99-juju-hardening.conf'
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super(SysctlConf, self).__init__(self.conffile,
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SysCtlHardeningContext(),
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template_dir=TEMPLATES_DIR,
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user='root', group='root',
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def post_write(self):
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subprocess.check_call(['sysctl', '-p', self.conffile])
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except subprocess.CalledProcessError as e:
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# NOTE: on some systems if sysctl cannot apply all settings it
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# will return non-zero as well.
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log("sysctl command returned an error (maybe some "
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"keys could not be set) - %s" % (e),
added
removed
hooks/charmhelpers/contrib/hardening/host/checks/sysctl.py
