selinux-refpolicy/support/gennetfilter.py
Topi Miettinen 4e1979a66b
gennetfilter: add rules for ICMP/ICMPv6 packets
Generate rules for SECMARKing ICMP and ICMPv6 packets as
icmp_packet_t.

Signed-off-by: Topi Miettinen <toiwoton@gmail.com>
2020-04-22 17:03:28 +03:00

264 lines
7.4 KiB
Python

#!/usr/bin/env python3
# Author: Chris PeBenito <cpebenito@tresys.com>
#
# Copyright (C) 2006 Tresys Technology, LLC
# 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, version 2.
import sys,getopt,re
NETPORT = re.compile(r"^network_port\(\s*\w+\s*(\s*,\s*\w+\s*,\s*[-0-9]+\s*,\s*\w+\s*)+\s*\)\s*(#|$)")
DEFAULT_INPUT_PACKET = "server_packet_t"
DEFAULT_OUTPUT_PACKET = "client_packet_t"
DEFAULT_MCS = "s0"
DEFAULT_MLS = "s0"
PACKET_INPUT = "_server_packet_t"
PACKET_OUTPUT = "_client_packet_t"
ICMP_PACKET = "icmp_packet_t"
class Port:
def __init__(self, proto, num, mls_sens):
# protocol of the port
self.proto = proto
# port number
self.num = num
# MLS sensitivity
self.mls_sens = mls_sens
# MCS categories
# not currently supported, so we always get s0
self.mcs_cats = DEFAULT_MCS
class Packet:
def __init__(self, prefix, ports):
# prefix
self.prefix = prefix
# A list of Ports
self.ports = ports
def print_nft_secmarks(packets,mls,mcs):
line = '\tsecmark default_input_packet {\n\t\t"system_u:object_r:'+DEFAULT_INPUT_PACKET
if mcs:
line += ":"+DEFAULT_MCS
elif mls:
line += ":"+DEFAULT_MLS
line += '"\n\t}\n\tsecmark default_output_packet {\n\t\t"system_u:object_r:'+DEFAULT_OUTPUT_PACKET
if mcs:
line += ":"+DEFAULT_MCS
elif mls:
line += ":"+DEFAULT_MLS
line += '"\n\t}'
print(line)
line = '\tsecmark icmp_packet {\n\t\t"system_u:object_r:'+ICMP_PACKET
if mcs:
line += ":"+DEFAULT_MCS
elif mls:
line += ":"+DEFAULT_MLS
line += '"\n\t}'
print(line)
for i in packets:
line = "\tsecmark "+i.prefix+'_input {\n\t\t"system_u:object_r:'+i.prefix+PACKET_INPUT
if mcs:
line += ":"+DEFAULT_MCS
elif mls:
line += ":"+DEFAULT_MLS
line += '"\n\t}\n\tsecmark '+i.prefix+'_output {\n\t\t"system_u:object_r:'+i.prefix+PACKET_OUTPUT
if mcs:
line += ":"+DEFAULT_MCS
elif mls:
line += ":"+DEFAULT_MLS
line += '"\n\t}'
print(line)
def print_nft_rules(packets,mls,mcs,direction):
for i in packets:
for j in i.ports:
print("\t\tct state new "+j.proto+" dport "+j.num+' meta secmark set "'+i.prefix+'_'+direction+'"')
print('\t\tip protocol icmp meta secmark set "icmp_packet"')
print('\t\tip6 nexthdr icmpv6 meta secmark set "icmp_packet"')
def print_input_rules(packets,mls,mcs):
line = "base -A selinux_new_input -j SECMARK --selctx system_u:object_r:"+DEFAULT_INPUT_PACKET
if mls:
line += ":"+DEFAULT_MLS
elif mcs:
line += ":"+DEFAULT_MCS
print(line)
line = "base -A selinux_new_input -p icmp -j SECMARK --selctx system_u:object_r:"+ICMP_PACKET
if mls:
line += ":"+DEFAULT_MLS
elif mcs:
line += ":"+DEFAULT_MCS
print(line)
line = "base -A selinux_new_input -p icmpv6 -j SECMARK --selctx system_u:object_r:"+ICMP_PACKET
if mls:
line += ":"+DEFAULT_MLS
elif mcs:
line += ":"+DEFAULT_MCS
print(line)
for i in packets:
for j in i.ports:
line="base -A selinux_new_input -p "+j.proto+" --dport "+re.sub('-', ':', j.num)+" -j SECMARK --selctx system_u:object_r:"+i.prefix+PACKET_INPUT
if mls:
line += ":"+j.mls_sens
elif mcs:
line += ":"+j.mcs_cats
print(line)
print("post -A selinux_new_input -j CONNSECMARK --save")
print("post -A selinux_new_input -j RETURN")
def print_output_rules(packets,mls,mcs):
line = "base -A selinux_new_output -j SECMARK --selctx system_u:object_r:"+DEFAULT_OUTPUT_PACKET
if mls:
line += ":"+DEFAULT_MLS
elif mcs:
line += ":"+DEFAULT_MCS
print(line)
line = "base -A selinux_new_output -p icmp -j SECMARK --selctx system_u:object_r:"+ICMP_PACKET
if mls:
line += ":"+DEFAULT_MLS
elif mcs:
line += ":"+DEFAULT_MCS
print(line)
line = "base -A selinux_new_output -p icmpv6 -j SECMARK --selctx system_u:object_r:"+ICMP_PACKET
if mls:
line += ":"+DEFAULT_MLS
elif mcs:
line += ":"+DEFAULT_MCS
print(line)
for i in packets:
for j in i.ports:
line = "base -A selinux_new_output -p "+j.proto+" --dport "+re.sub('-', ':', j.num)+" -j SECMARK --selctx system_u:object_r:"+i.prefix+PACKET_OUTPUT
if mls:
line += ":"+j.mls_sens
elif mcs:
line += ":"+j.mcs_cats
print(line)
print("post -A selinux_new_output -j CONNSECMARK --save")
print("post -A selinux_new_output -j RETURN")
def parse_corenet(file_name):
packets = []
corenet_te_in = open(file_name, "r")
while True:
corenet_line = corenet_te_in.readline()
# If EOF has been reached:
if not corenet_line:
break
if NETPORT.match(corenet_line):
corenet_line = corenet_line.strip()
# parse out the parameters
openparen = corenet_line.find('(')+1
closeparen = corenet_line.find(')',openparen)
parms = re.split(r'[^-a-zA-Z0-9_]+',corenet_line[openparen:closeparen])
name = parms[0]
del parms[0]
ports = []
while len(parms) > 0:
# add a port combination.
ports.append(Port(parms[0],parms[1],parms[2]))
del parms[:3]
packets.append(Packet(name,ports))
corenet_te_in.close()
return packets
def print_netfilter_config_nft(packets,mls,mcs):
print("#!/usr/sbin/nft -f")
print("flush ruleset")
print("table inet security {")
print_nft_secmarks(packets,mls,mcs)
print("\tchain INPUT {")
print("\t\ttype filter hook input priority 0; policy accept;")
print('\t\tct state new meta secmark set "default_input_packet"')
print_nft_rules(packets,mls,mcs,'input')
print("\t\tct state new ct secmark set meta secmark")
print("\t\tct state established,related meta secmark set ct secmark")
print("\t}")
print("\tchain FORWARD {")
print("\t\ttype filter hook forward priority 0; policy accept;")
print("\t}")
print("\tchain OUTPUT {")
print("\t\ttype filter hook output priority 0; policy accept;")
print('\t\tct state new meta secmark set "default_output_packet"')
print_nft_rules(packets,mls,mcs,'output')
print("\t\tct state new ct secmark set meta secmark")
print("\t\tct state established,related meta secmark set ct secmark")
print("\t}")
print("}")
def print_netfilter_config_iptables(packets,mls,mcs):
print("pre *mangle")
print("pre :PREROUTING ACCEPT [0:0]")
print("pre :INPUT ACCEPT [0:0]")
print("pre :FORWARD ACCEPT [0:0]")
print("pre :OUTPUT ACCEPT [0:0]")
print("pre :POSTROUTING ACCEPT [0:0]")
print("pre :selinux_input - [0:0]")
print("pre :selinux_output - [0:0]")
print("pre :selinux_new_input - [0:0]")
print("pre :selinux_new_output - [0:0]")
print("pre -A INPUT -j selinux_input")
print("pre -A OUTPUT -j selinux_output")
print("pre -A selinux_input -m state --state NEW -j selinux_new_input")
print("pre -A selinux_input -m state --state RELATED,ESTABLISHED -j CONNSECMARK --restore")
print("pre -A selinux_output -m state --state NEW -j selinux_new_output")
print("pre -A selinux_output -m state --state RELATED,ESTABLISHED -j CONNSECMARK --restore")
print_input_rules(packets,mls,mcs)
print_output_rules(packets,mls,mcs)
print("post COMMIT")
mls = False
mcs = False
nft = False
try:
opts, paths = getopt.getopt(sys.argv[1:],'mcn',['mls','mcs','nft'])
except getopt.GetoptError:
print("Invalid options.")
sys.exit(1)
for o, a in opts:
if o in ("-c","--mcs"):
mcs = True
if o in ("-m","--mls"):
mls = True
if o in ("-n","--nft"):
nft = True
if len(paths) == 0:
sys.stderr.write("Need a path for corenetwork.te.in!\n")
sys.exit(1)
elif len(paths) > 1:
sys.stderr.write("Ignoring extra specified paths\n")
packets=parse_corenet(paths[0])
if nft:
print_netfilter_config_nft(packets,mls,mcs)
else:
print_netfilter_config_iptables(packets,mls,mcs)