shell bypass 403
# -*- coding: utf-8 -*-
#
# Copyright (C) 2010-2016 Red Hat, Inc.
#
# Authors:
# Thomas Woerner <twoerner@redhat.com>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# 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/>.
#
__all__ = [ "ebtables" ]
import os.path
from firewall.core.prog import runProg
from firewall.core.logger import log
from firewall.functions import tempFile, readfile, splitArgs
from firewall.config import COMMANDS
from firewall.core import ipXtables # some common stuff lives there
from firewall.errors import FirewallError, INVALID_IPV
import string
BUILT_IN_CHAINS = {
"broute": [ "BROUTING" ],
"nat": [ "PREROUTING", "POSTROUTING", "OUTPUT" ],
"filter": [ "INPUT", "OUTPUT", "FORWARD" ],
}
DEFAULT_RULES = { }
LOG_RULES = { }
OUR_CHAINS = {} # chains created by firewalld
for table in BUILT_IN_CHAINS.keys():
DEFAULT_RULES[table] = [ ]
OUR_CHAINS[table] = set()
for chain in BUILT_IN_CHAINS[table]:
DEFAULT_RULES[table].append("-N %s_direct" % chain)
DEFAULT_RULES[table].append("-I %s 1 -j %s_direct" % (chain, chain))
DEFAULT_RULES[table].append("-I %s_direct 1 -j RETURN" % chain)
OUR_CHAINS[table].add("%s_direct" % chain)
class ebtables(object):
ipv = "eb"
name = "ebtables"
zones_supported = False # ebtables only supported with direct interface
def __init__(self):
self._command = COMMANDS[self.ipv]
self._restore_command = COMMANDS["%s-restore" % self.ipv]
self.restore_noflush_option = self._detect_restore_noflush_option()
self.concurrent_option = self._detect_concurrent_option()
self.fill_exists()
self.available_tables = []
def fill_exists(self):
self.command_exists = os.path.exists(self._command)
self.restore_command_exists = os.path.exists(self._restore_command)
def _detect_concurrent_option(self):
# Do not change any rules, just try to use the --concurrent option
# with -L
concurrent_option = ""
ret = runProg(self._command, ["--concurrent", "-L"])
if ret[0] == 0:
concurrent_option = "--concurrent" # concurrent for ebtables lock
return concurrent_option
def _detect_restore_noflush_option(self):
# Do not change any rules, just try to use the restore command
# with --noflush
rules = [ ]
try:
self.set_rules(rules, "off")
except ValueError:
return False
return True
def __run(self, args):
# convert to string list
_args = [ ]
if self.concurrent_option and self.concurrent_option not in args:
_args.append(self.concurrent_option)
_args += ["%s" % item for item in args]
log.debug2("%s: %s %s", self.__class__, self._command, " ".join(_args))
(status, ret) = runProg(self._command, _args)
if status != 0:
raise ValueError("'%s %s' failed: %s" % (self._command,
" ".join(args), ret))
return ret
def _rule_validate(self, rule):
for str in ["%%REJECT%%", "%%ICMP%%", "%%LOGTYPE%%"]:
if str in rule:
raise FirewallError(INVALID_IPV,
"'%s' invalid for ebtables" % str)
def is_chain_builtin(self, ipv, table, chain):
return table in BUILT_IN_CHAINS and \
chain in BUILT_IN_CHAINS[table]
def build_chain_rules(self, add, table, chain):
rules = []
if add:
rules.append([ "-t", table, "-N", chain ])
rules.append([ "-t", table, "-I", chain, "1", "-j", "RETURN" ])
else:
rules.append([ "-t", table, "-X", chain ])
return rules
def build_rule(self, add, table, chain, index, args):
rule = [ "-t", table ]
if add:
rule += [ "-I", chain, str(index) ]
else:
rule += [ "-D", chain ]
rule += args
return rule
def reverse_rule(self, args):
return ipXtables.common_reverse_rule(args)
def check_passthrough(self, args):
ipXtables.common_check_passthrough(args)
def reverse_passthrough(self, args):
return ipXtables.common_reverse_passthrough(args)
def set_rules(self, rules, log_denied):
temp_file = tempFile()
table = "filter"
table_rules = { }
for _rule in rules:
rule = _rule[:]
self._rule_validate(rule)
# get table form rule
for opt in [ "-t", "--table" ]:
try:
i = rule.index(opt)
except ValueError:
pass
else:
if len(rule) >= i+1:
rule.pop(i)
table = rule.pop(i)
# we can not use joinArgs here, because it would use "'" instead
# of '"' for the start and end of the string, this breaks
# iptables-restore
for i in range(len(rule)):
for c in string.whitespace:
if c in rule[i] and not (rule[i].startswith('"') and
rule[i].endswith('"')):
rule[i] = '"%s"' % rule[i]
table_rules.setdefault(table, []).append(rule)
for table in table_rules:
temp_file.write("*%s\n" % table)
for rule in table_rules[table]:
temp_file.write(" ".join(rule) + "\n")
temp_file.close()
stat = os.stat(temp_file.name)
log.debug2("%s: %s %s", self.__class__, self._restore_command,
"%s: %d" % (temp_file.name, stat.st_size))
args = [ ]
args.append("--noflush")
(status, ret) = runProg(self._restore_command, args,
stdin=temp_file.name)
if log.getDebugLogLevel() > 2:
lines = readfile(temp_file.name)
if lines is not None:
i = 1
for line in lines:
log.debug3("%8d: %s" % (i, line), nofmt=1, nl=0)
if not line.endswith("\n"):
log.debug3("", nofmt=1)
i += 1
os.unlink(temp_file.name)
if status != 0:
raise ValueError("'%s %s' failed: %s" % (self._restore_command,
" ".join(args), ret))
return ret
def set_rule(self, rule, log_denied):
self._rule_validate(rule)
return self.__run(rule)
def get_available_tables(self, table=None):
ret = []
tables = [ table ] if table else BUILT_IN_CHAINS.keys()
for table in tables:
if table in self.available_tables:
ret.append(table)
else:
try:
self.__run(["-t", table, "-L"])
self.available_tables.append(table)
ret.append(table)
except ValueError:
log.debug1("ebtables table '%s' does not exist." % table)
return ret
def get_zone_table_chains(self, table):
return {}
def build_flush_rules(self):
rules = []
for table in BUILT_IN_CHAINS.keys():
if table not in self.get_available_tables():
continue
# Flush firewall rules: -F
# Delete firewall chains: -X
# Set counter to zero: -Z
for flag in [ "-F", "-X", "-Z" ]:
rules.append(["-t", table, flag])
return rules
def build_set_policy_rules(self, policy):
rules = []
for table in BUILT_IN_CHAINS.keys():
if table not in self.get_available_tables():
continue
for chain in BUILT_IN_CHAINS[table]:
rules.append(["-t", table, "-P", chain, policy])
return rules
def build_default_tables(self):
# nothing to do, they always exist
return []
def build_default_rules(self, log_denied="off"):
default_rules = []
for table in DEFAULT_RULES:
if table not in self.get_available_tables():
continue
_default_rules = DEFAULT_RULES[table][:]
if log_denied != "off" and table in LOG_RULES:
_default_rules.extend(LOG_RULES[table])
prefix = [ "-t", table ]
for rule in _default_rules:
if type(rule) == list:
default_rules.append(prefix + rule)
else:
default_rules.append(prefix + splitArgs(rule))
return default_rules
def is_ipv_supported(self, ipv):
return ipv == self.ipv