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firewall
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feat(zones): Zone resolver + Add IPs into NFT sets

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python
v-lafeychine 9 months ago
parent 7c9f6d656b
commit 6cb00345ac
Signed by: v-lafeychine
GPG Key ID: F46CAAD27C7AB0D5
2 changed files with 152 additions and 48 deletions
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177
firewall.py
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@ -1,22 +1,22 @@
#!/usr/bin/env python3
from argparse import ArgumentParser, FileType
from dataclasses import dataclass
from enum import Enum
from graphlib import TopologicalSorter
from netaddr import IPSet
from ipaddress import IPv4Network, IPv6Network
from nftables import Nftables
from pydantic import (
BaseModel,
Extra,
FilePath,
IPvAnyAddress,
IPvAnyNetwork,
conint,
parse_obj_as,
validator,
root_validator,
)
from typing import TypeAlias
from typing import Generator, TypeAlias
from yaml import safe_load
import nft
@ -24,8 +24,10 @@ import nft
# ==========[ YAML MODEL ]======================================================
class RestrictiveBaseModel(BaseModel, extra=Extra.forbid):
pass
class RestrictiveBaseModel(BaseModel):
class Config:
allow_mutation = False
extra = Extra.forbid
# Ports
@ -59,25 +61,33 @@ class PortRange(str):
# Zones
class ZoneName(str):
pass
ZoneName: TypeAlias = str
class ZoneEntry(RestrictiveBaseModel):
addrs: set[IPvAnyNetwork] = set()
files: set[FilePath] = set()
file: FilePath | None = None
negate: bool = False
zones: set[ZoneName] = set()
@root_validator()
def validate_mutually_exactly_one(cls, values):
fields = ["addrs", "file", "zones"]
if sum(1 for field in fields if values.get(field)) != 1:
raise ValueError(f"exactly one of {fields} must be set")
return values
# Blacklist
class BlackList(RestrictiveBaseModel):
addr: list[IPvAnyAddress] = list()
class Blacklist(RestrictiveBaseModel):
blocked: set[IPvAnyNetwork | ZoneName] = set()
# Reverse Path Filter
class ReversePathFilter(RestrictiveBaseModel):
enabled: bool = False
interfaces: set[str] = set()
# Filters
@ -88,13 +98,13 @@ class Verdict(str, Enum):
class TcpProtocol(RestrictiveBaseModel):
dport: list[Port | PortRange] = list()
sport: list[Port | PortRange] = list()
dport: set[Port | PortRange] = set()
sport: set[Port | PortRange] = set()
class UdpProtocol(RestrictiveBaseModel):
dport: list[Port | PortRange] = list()
sport: list[Port | PortRange] = list()
dport: set[Port | PortRange] = set()
sport: set[Port | PortRange] = set()
class Protocols(RestrictiveBaseModel):
@ -109,13 +119,13 @@ class Rule(RestrictiveBaseModel):
iif: str | None
oif: str | None
protocols: Protocols = Protocols()
src: IPvAnyNetwork | ZoneName | list[IPvAnyNetwork | ZoneName] | None
dst: IPvAnyNetwork | ZoneName | list[IPvAnyNetwork | ZoneName] | None
src: IPvAnyNetwork | ZoneName | set[IPvAnyNetwork | ZoneName] | None
dst: IPvAnyNetwork | ZoneName | set[IPvAnyNetwork | ZoneName] | None
verdict: Verdict = Verdict.accept
class ForwardRule(Rule):
dest: ZoneName | list[IPvAnyNetwork | ZoneName] | None
dest: IPvAnyNetwork | ZoneName | set[IPvAnyNetwork | ZoneName] | None
class Filter(RestrictiveBaseModel):
@ -126,7 +136,7 @@ class Filter(RestrictiveBaseModel):
# Nat
class SNat(RestrictiveBaseModel):
addr: IPvAnyAddress
addr: IPvAnyNetwork
persistent: bool = True
@ -137,8 +147,8 @@ class Nat(RestrictiveBaseModel):
# Root model
class Firewall(RestrictiveBaseModel):
zones: dict[ZoneName, ZoneEntry] = list()
blacklist: BlackList = BlackList()
zones: dict[ZoneName, ZoneEntry] = dict()
blacklist: Blacklist = Blacklist()
reverse_path_filter: ReversePathFilter = ReversePathFilter()
filter: Filter = Filter()
nat: list[Nat] = list()
@ -147,27 +157,101 @@ class Firewall(RestrictiveBaseModel):
# ==========[ ZONES ]===========================================================
# Zones: Graph resolver
def resolve_zones(zones_entries: list[ZoneEntry]) -> None:
zone_name = {entry.name: entry.zones for entry in zones_entries}
class ZoneFile(RestrictiveBaseModel):
__root__: set[IPvAnyNetwork]
@dataclass
class ResolvedZone:
addrs: set[IPvAnyNetwork]
negate: bool
for name in TopologicalSorter(zone_name).static_order():
print(name)
Zones: TypeAlias = dict[ZoneName, ResolvedZone]
# TODO: Check negation inclusion
def resolve_zones(yaml_zones: dict[ZoneName, ZoneEntry]) -> Zones:
zones: Zones = {}
zone_graph = {name: entry.zones for (name, entry) in yaml_zones.items()}
for name in TopologicalSorter(zone_graph).static_order():
if yaml_zones[name].addrs:
zones[name] = ResolvedZone(
yaml_zones[name].addrs, yaml_zones[name].negate
)
elif yaml_zones[name].file is not None:
with open(yaml_zones[name].file, "r") as file:
try:
yaml_addrs = ZoneFile(__root__=safe_load(file))
except Exception as e:
raise Exception(
f"YAML parsing failed of the included file '{yaml_zones[name].file}': {e}"
)
zones[name] = ResolvedZone(
yaml_addrs.__root__, yaml_zones[name].negate
)
elif yaml_zones[name].zones:
addrs: set[IPvAnyNetwork] = set()
for zone in yaml_zones[name].zones:
addrs.update(yaml_zones[zone].addrs)
zones[name] = ResolvedZone(addrs, yaml_zones[name].negate)
return zones
# ==========[ PARSER ]==========================================================
def parse_blacklist(blacklist: BlackList) -> nft.Table:
table = nft.Table(name="blacklist", family="inet")
def split_v4_v6(
addrs: Generator[IPvAnyNetwork, None, None]
) -> tuple[set[IPv4Network], set[IPv6Network]]:
v4, v6 = set(), set()
for addr in addrs:
match addr:
case IPv4Network():
v4.add(addr)
case IPv6Network():
v6.add(addr)
return v4, v6
def zones_blacklist(
blacklist: Blacklist, zones: Zones
) -> Generator[IPvAnyNetwork, None, None]:
for blocked in blacklist.blocked:
match blocked:
case ZoneName():
zone = zones[blocked]
if zone.negate:
raise ValueError(
f"zone '{blocked}' cannot be negated in the blacklist"
)
yield from zone.addrs
case IPv4Network() | IPv6Network():
yield blocked
def parse_blacklist(blacklist: Blacklist, zones: Zones) -> nft.Table:
# Sets
set_v4 = nft.Set(name="blacklist_v4", type="ipv4_addr", flags=["interval"])
set_v6 = nft.Set(name="blacklist_v6", type="ipv6_addr", flags=["interval"])
table.sets.extend([set_v4, set_v6])
# Elements
ip_v4, ip_v6 = split_v4_v6(zones_blacklist(blacklist, zones))
set_v4.elements.extend(ip_v4)
set_v6.elements.extend(ip_v6)
# Chains
chain_filter = nft.Chain(
@ -192,14 +276,18 @@ def parse_blacklist(blacklist: BlackList) -> nft.Table:
chain_filter.rules.append(nft.Rule([chain_v4, nft.Verdict("drop")]))
chain_filter.rules.append(nft.Rule([chain_v6, nft.Verdict("drop")]))
# Generate elements
table = nft.Table(name="blacklist", family="inet")
table.chains.extend([chain_filter])
table.sets.extend([set_v4, set_v6])
return table
def parse_firewall(firewall: Firewall) -> nft.Ruleset:
def parse_firewall(firewall: Firewall, zones: Zones) -> nft.Ruleset:
ruleset = nft.Ruleset(flush=True)
blacklist = parse_blacklist(firewall.blacklist)
blacklist = parse_blacklist(firewall.blacklist, zones)
ruleset.tables.extend([blacklist])
return ruleset
@ -211,10 +299,6 @@ def parse_firewall(firewall: Firewall) -> nft.Ruleset:
def send_to_nftables(cmd: nft.JsonNftables) -> int:
nft = Nftables()
import json
print(json.dumps(cmd, indent=4))
try:
nft.json_validate(cmd)
except Exception as e:
@ -238,9 +322,26 @@ def main() -> int:
parser.add_argument("file", type=FileType("r"), help="YAML rule file")
args = parser.parse_args()
rules = Firewall(**safe_load(args.file))
return send_to_nftables(parse_firewall(rules).to_nft())
try:
firewall = Firewall(**safe_load(args.file))
except Exception as e:
print(f"YAML parsing failed of the file '{args.file}': {e}")
return 1
try:
zones = resolve_zones(firewall.zones)
except Exception as e:
print(f"Zone resolution failed: {e}")
return 1
# try:
json = parse_firewall(firewall, zones)
# except Exception as e:
# print(f"Firewall translation failed: {e}")
# return 1
return send_to_nftables(json.to_nft())
if __name__ == "__main__":

23
nft.py
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@ -1,5 +1,6 @@
from dataclasses import dataclass, field
from itertools import chain
from pydantic import IPvAnyNetwork
from typing import Any, TypeVar
T = TypeVar("T")
@ -10,25 +11,29 @@ def flatten(l: list[list[T]]) -> list[T]:
return list(chain.from_iterable(l))
def ip_to_nft(ip: IPvAnyNetwork) -> JsonNftables:
return {"prefix": {"addr": str(ip.network_address), "len": ip.prefixlen}}
@dataclass
class Set:
name: str
flags: list[str]
type: str | list[str]
flags: list[str] | None = None
type: str | list[str] | None = None
elements: list[IPvAnyNetwork] = field(default_factory=list)
def to_nft(self, family: str, table: str) -> JsonNftables:
set: JsonNftables = {
"name": self.name,
"family": family,
"table": table,
"flags": self.flags,
"type": self.type,
}
if self.flags is not None:
set["flags"] = self.flags
if self.type is not None:
set["type"] = self.type
if self.elements:
set["elem"] = [ip_to_nft(ip) for ip in self.elements]
return {"add": {"set": set}}
@ -146,9 +151,7 @@ class Table:
sets: list[Set] = field(default_factory=list)
def to_nft(self) -> list[JsonNftables]:
commands = [
{"add": {"table": {"family": self.family, "name": self.name}}}
]
commands = [{"add": {"table": {"family": self.family, "name": self.name}}}]
for set in self.sets:
commands.append(set.to_nft(self.family, self.name))

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