Refactor VM lifecycle management and enhance validation
- Introduced a new method `installed_kernel` in `ImageStore` to handle kernel verification and checksum validation. - Updated `Installer` to include additional packages: `nftables` and `conntrack`. - Refined `LifecycleService` to improve error handling and state management during VM creation, starting, stopping, and deletion. - Enhanced port management with new methods for setting and syncing ports, including validation for port rules. - Improved error handling in `StateStore` to raise specific `NotFoundError` and `ConflictError` exceptions. - Updated network management to ensure proper TAP device handling and firewall integration. - Enhanced API responses in `vms.py` to include policy status for better client-side handling. - Added validation for VM names and ports in `validation.py` to enforce stricter rules and prevent conflicts.
This commit is contained in:
+496
@@ -0,0 +1,496 @@
|
||||
"""Private IPv4 service filtering, not host-port forwarding or publishing.
|
||||
|
||||
The lifecycle owner must serialize mutations, keep a live VM's identity immutable,
|
||||
install the policy before starting its guest, and quarantine before teardown.
|
||||
Only bridge/TAP traffic is covered; do not offload it around the bridge hooks.
|
||||
Before making a TAP usable, attach it to an STP-disabled software bridge and set
|
||||
the TAP's bridge_slave group_fwd_mask bit 0x4000. Otherwise Linux can deliver LLDP
|
||||
(and STP) before *any* bridge hook and learn spoofed MACs. Network/lifecycle owns
|
||||
these link settings; this manager only verifies them when the TAP exists.
|
||||
No br_netfilter sysctls, NAT, persistent applied flags, or live conntrack flushes
|
||||
are used. Native bridge conntrack (Linux >= 5.3) and nft JSON support are required.
|
||||
"""
|
||||
|
||||
from __future__ import annotations
|
||||
|
||||
import hashlib
|
||||
import json
|
||||
import re
|
||||
import uuid
|
||||
from ipaddress import IPv4Address, IPv4Network
|
||||
from types import SimpleNamespace
|
||||
from typing import Any
|
||||
|
||||
from .config import Settings
|
||||
from .domain import PortRule, VmRecord
|
||||
from .errors import UvmError, ValidationError
|
||||
from .system import CommandResult, CommandRunner
|
||||
|
||||
|
||||
_COMMAND_TIMEOUT_S = 5.0
|
||||
_PRIVATE_NETWORKS = tuple(IPv4Network(value) for value in (
|
||||
"10.0.0.0/8", "172.16.0.0/12", "192.168.0.0/16",
|
||||
))
|
||||
|
||||
|
||||
def _match(left: dict[str, Any], right: Any, op: str = "==") -> dict[str, Any]:
|
||||
return {"match": {"op": op, "left": left, "right": right}}
|
||||
|
||||
|
||||
def _payload(protocol: str, field: str) -> dict[str, Any]:
|
||||
return {"payload": {"protocol": protocol, "field": field}}
|
||||
|
||||
|
||||
def _ct(key: str, direction: str | None = None) -> dict[str, Any]:
|
||||
# nft 1.0.9 parser_json.c/ct.c use the literal keys "ip saddr"/"ip daddr".
|
||||
# Its CT parser ignores the "family" property advertised by the JSON manual.
|
||||
return {"ct": {"key": key, **({"dir": direction} if direction else {})}}
|
||||
|
||||
|
||||
class FirewallManager:
|
||||
"""Own one table per (resolved settings.base, VM id) in the current netns.
|
||||
|
||||
``ports=None`` is legacy/unmanaged, not an empty allowlist. Normal apply
|
||||
refuses it; quarantine works even without a port policy or valid IP/MAC.
|
||||
Errors leave existing rules in place (or the committed replacement on a
|
||||
readback/timeout failure). Callers must not start/release a VM on an error.
|
||||
"""
|
||||
|
||||
def __init__(self, settings: Settings, runner: CommandRunner) -> None:
|
||||
self._settings = settings
|
||||
self._runner = runner
|
||||
|
||||
def apply(self, vm: VmRecord, *, quarantine: bool = False) -> None:
|
||||
"""Atomically install/replace only this VM's owned table; retain CT state."""
|
||||
expected = self._policy(vm, quarantine=quarantine)
|
||||
if not self._bridge_paths_safe(vm):
|
||||
raise UvmError(
|
||||
"firewall needs an STP-disabled software bridge and TAP bridge_slave "
|
||||
"group_fwd_mask bit 0x4000 (LLDP forwarding) before enforcement"
|
||||
)
|
||||
table = expected[0]["table"]
|
||||
current = self._read_table(table["name"])
|
||||
commands = []
|
||||
if current is not None:
|
||||
commands.append(self._delete_owned(current, table))
|
||||
# Exclusive create plus deletion by handle also protects against a table
|
||||
# being replaced by a foreign owner between inspection and commit.
|
||||
commands.append({"create": expected[0]})
|
||||
commands.extend({"add": item} for item in expected[1:])
|
||||
self._transaction(commands)
|
||||
installed = self._read_table(table["name"])
|
||||
if installed is None or _normalize(installed) != _normalize(expected):
|
||||
raise UvmError("firewall readback differs from the requested policy; keep VM isolated")
|
||||
|
||||
def remove(self, vm: VmRecord) -> None:
|
||||
"""Remove an owned table only after the TAP is gone; absence is harmless."""
|
||||
self._require_offline(vm)
|
||||
table = self._table_identity(vm)
|
||||
current = self._read_table(table["name"])
|
||||
if current is not None:
|
||||
self._transaction([self._delete_owned(current, table)])
|
||||
|
||||
def status(self, vm: VmRecord) -> str:
|
||||
"""Inspect actual hooks, ordered rules, identity and complete port set.
|
||||
|
||||
Missing legacy tables are unmanaged. Foreign or altered tables are
|
||||
drift; failed inspection/invalid metadata is unknown. A legacy VM can
|
||||
report quarantined. This is a ruleset snapshot, not a reachability test.
|
||||
"""
|
||||
try:
|
||||
table = self._table_identity(vm)
|
||||
current = self._read_table(table["name"])
|
||||
if current is None:
|
||||
return "unmanaged" if getattr(vm, "ports", None) is None else "missing"
|
||||
if _normalize(current) == _normalize(self._policy(vm, quarantine=True)):
|
||||
return "quarantined" if self._bridge_paths_safe(vm) else "drift"
|
||||
if getattr(vm, "ports", None) is not None:
|
||||
if _normalize(current) == _normalize(self._policy(vm, quarantine=False)):
|
||||
return "enforced" if self._bridge_paths_safe(vm) else "drift"
|
||||
return "drift"
|
||||
except (UvmError, ValueError, TypeError, KeyError):
|
||||
return "unknown"
|
||||
|
||||
def check_available(self) -> None:
|
||||
"""Check cleanup tooling, kernel and a full non-committing nft policy."""
|
||||
self._run(("conntrack", "--version"))
|
||||
release = self._run(("uname", "-r")).stdout.strip()
|
||||
version = re.match(r"^(\d+)\.(\d+)", release)
|
||||
if version is None or tuple(map(int, version.groups())) < (5, 3):
|
||||
raise UvmError("private ports require Linux >= 5.3 with native bridge conntrack")
|
||||
probe = SimpleNamespace(
|
||||
id=f"probe-{uuid.uuid4().hex}", tap=f"uvm{uuid.uuid4().hex[:11]}",
|
||||
guest_ip="10.0.0.2", gateway="10.0.0.1",
|
||||
network="10.0.0.0/24", mac="02:00:00:00:00:02",
|
||||
ports=(PortRule(443),),
|
||||
)
|
||||
policy = self._policy(probe, quarantine=False) # type: ignore[arg-type]
|
||||
commands = [{"create": policy[0]}, *({"add": item} for item in policy[1:])]
|
||||
try:
|
||||
self._transaction(commands, check_only=True)
|
||||
except UvmError as error:
|
||||
raise UvmError(f"nft bridge/conntrack policy is unavailable: {error}") from error
|
||||
|
||||
def cleanup_connections(self, vm: VmRecord) -> None:
|
||||
"""Offline, IP-scoped CT deletion before address reuse, never for close.
|
||||
|
||||
All four tuple addresses are checked, including NAT reply tuples. A
|
||||
failed deletion is tolerated only if a successful list proves absence.
|
||||
The caller must retain the address reservation until this succeeds.
|
||||
"""
|
||||
self._require_offline(vm)
|
||||
address = self._guest_ip(vm)
|
||||
for field in ("--orig-src", "--orig-dst", "--reply-src", "--reply-dst"):
|
||||
selector = ("--family", "ipv4", field, address)
|
||||
self._run(("conntrack", "--delete", *selector), check=False)
|
||||
remaining = self._run(("conntrack", "--list", *selector))
|
||||
if remaining.stdout.strip():
|
||||
raise UvmError(f"conntrack entries remain for {address}; do not reuse its IP")
|
||||
|
||||
def _run(self, command: tuple[str, ...], **kwargs: Any) -> CommandResult:
|
||||
return self._runner.run(
|
||||
command, capture=True, timeout=_COMMAND_TIMEOUT_S, **kwargs,
|
||||
)
|
||||
|
||||
def _transaction(self, commands: list[dict[str, Any]], *, check_only: bool = False) -> None:
|
||||
args = ("nft", "--json", *(("--check",) if check_only else ()), "-f", "-")
|
||||
self._run(args, input_text=json.dumps({"nftables": commands}))
|
||||
|
||||
def _table_identity(self, vm: VmRecord) -> dict[str, Any]:
|
||||
if not isinstance(vm.id, str) or not vm.id:
|
||||
raise ValidationError("firewall requires a nonempty VM ID")
|
||||
identity = json.dumps([str(self._settings.base.resolve()), vm.id]).encode("utf-8")
|
||||
digest = hashlib.sha256(identity).hexdigest()
|
||||
return {"family": "bridge", "name": f"uvm_fw_{digest[:24]}",
|
||||
"comment": f"uvm-private-ports:v1:{digest}"}
|
||||
|
||||
def _tap(self, vm: VmRecord) -> str:
|
||||
if not isinstance(vm.tap, str) or re.fullmatch(r"[A-Za-z0-9_][A-Za-z0-9_.-]{0,14}", vm.tap) is None:
|
||||
raise ValidationError("firewall requires an exact, safe TAP name (1-15 characters)")
|
||||
if vm.tap in {self._settings.bridge, getattr(vm, "bridge", None)}:
|
||||
raise ValidationError("firewall TAP must not be the bridge itself")
|
||||
return vm.tap
|
||||
|
||||
def _guest_ip(self, vm: VmRecord) -> str:
|
||||
try:
|
||||
address = IPv4Address(vm.guest_ip)
|
||||
network = IPv4Network(getattr(vm, "network", None) or self._settings.network)
|
||||
except (ValueError, TypeError) as error:
|
||||
raise ValidationError("firewall requires a valid guest IPv4 address/network") from error
|
||||
gateway = str(getattr(vm, "gateway", None) or self._settings.gateway)
|
||||
if (not any(address in private for private in _PRIVATE_NETWORKS)
|
||||
or address not in network
|
||||
or address in {network.network_address, network.broadcast_address}
|
||||
or str(address) == gateway):
|
||||
raise ValidationError("firewall requires a usable private guest IP inside its network")
|
||||
return str(address)
|
||||
|
||||
def _links(self) -> list[dict[str, Any]]:
|
||||
try:
|
||||
links = json.loads(self._run(("ip", "-j", "-d", "link", "show")).stdout)
|
||||
if not isinstance(links, list) or any(
|
||||
not isinstance(link, dict) or not isinstance(link.get("ifname"), str)
|
||||
for link in links
|
||||
):
|
||||
raise ValueError("invalid link listing")
|
||||
except (ValueError, TypeError) as error:
|
||||
raise UvmError("cannot inspect network interfaces; retaining firewall/conntrack state") from error
|
||||
return links
|
||||
|
||||
def _bridge_paths_safe(self, vm: VmRecord) -> bool:
|
||||
links = self._links()
|
||||
name = self._tap(vm)
|
||||
taps = [link for link in links if link["ifname"] == name]
|
||||
if not taps:
|
||||
return True # Policy may precede TAP creation; main must prepare it before bringing it up.
|
||||
if len(taps) != 1:
|
||||
return False
|
||||
tap = taps[0]
|
||||
bridges = [link for link in links if tap.get("master") in (link["ifname"], link.get("ifindex"))]
|
||||
if len(bridges) != 1:
|
||||
return False
|
||||
try:
|
||||
port = tap["linkinfo"]
|
||||
bridge = bridges[0]["linkinfo"]
|
||||
mask = int(str(port["info_slave_data"]["group_fwd_mask"]), 0)
|
||||
return (port["info_slave_kind"] == "bridge" and bridge["info_kind"] == "bridge"
|
||||
and bridge["info_data"]["stp_state"] == 0
|
||||
and 0 <= mask <= 65535 and bool(mask & 0x4000))
|
||||
except (KeyError, TypeError, ValueError):
|
||||
return False
|
||||
|
||||
def _require_offline(self, vm: VmRecord) -> None:
|
||||
tap = self._tap(vm)
|
||||
if any(link["ifname"] == tap for link in self._links()):
|
||||
raise UvmError(f"TAP {tap} still exists; quarantine it and remove the TAP first")
|
||||
|
||||
def _read_table(self, name: str) -> list[dict[str, Any]] | None:
|
||||
# A successful table inventory, not a localized 'not found' error,
|
||||
# distinguishes missing policy from missing privileges/tools.
|
||||
def objects(command: tuple[str, ...]) -> list[dict[str, Any]]:
|
||||
try:
|
||||
data = json.loads(self._run(command).stdout)["nftables"]
|
||||
if not isinstance(data, list) or any(
|
||||
not isinstance(item, dict) or len(item) != 1
|
||||
or not isinstance(next(iter(item.values())), dict) for item in data
|
||||
):
|
||||
raise ValueError("invalid nft object list")
|
||||
return [item for item in data if "metainfo" not in item]
|
||||
except (ValueError, KeyError, TypeError) as error:
|
||||
raise UvmError("could not inspect nft bridge tables") from error
|
||||
|
||||
tables = objects(("nft", "--json", "list", "tables", "bridge"))
|
||||
if any("table" not in item or item["table"].get("family") != "bridge"
|
||||
or not isinstance(item["table"].get("name"), str) for item in tables):
|
||||
raise UvmError("invalid nft bridge table inventory")
|
||||
matches = [item for item in tables if item["table"].get("name") == name]
|
||||
if not matches:
|
||||
return None
|
||||
if len(matches) != 1:
|
||||
raise UvmError("ambiguous nft bridge table inventory")
|
||||
data = objects(("nft", "--json", "--numeric-protocol", "list", "table", "bridge", name))
|
||||
headers = [item["table"] for item in data if "table" in item]
|
||||
if len(headers) != 1 or headers[0].get("name") != name or headers[0].get("family") != "bridge":
|
||||
raise UvmError("invalid nft bridge table snapshot")
|
||||
return data
|
||||
|
||||
@staticmethod
|
||||
def _delete_owned(current: list[dict[str, Any]], table: dict[str, Any]) -> dict[str, Any]:
|
||||
header = next(item["table"] for item in current if "table" in item)
|
||||
if any(header.get(key) != value for key, value in table.items()):
|
||||
raise UvmError(f"refusing to touch foreign nft table {table['name']}")
|
||||
handle = header.get("handle")
|
||||
if type(handle) is not int or handle <= 0:
|
||||
raise UvmError("owned nft table has no valid handle; refusing unsafe deletion")
|
||||
return {"delete": {"table": {"family": "bridge", "handle": handle}}}
|
||||
|
||||
def _policy(self, vm: VmRecord, *, quarantine: bool) -> list[dict[str, Any]]:
|
||||
ports = getattr(vm, "ports", None)
|
||||
if ports is None and not quarantine:
|
||||
raise ValidationError("legacy VM has no managed port policy; only quarantine is allowed")
|
||||
table = self._table_identity(vm)
|
||||
tap = self._tap(vm)
|
||||
scope = {"family": "bridge", "table": table["name"]}
|
||||
policy: list[dict[str, Any]] = [{"table": table}]
|
||||
|
||||
def chain(name: str, hook: str | None = None, priority: int = 0) -> None:
|
||||
definition = {**scope, "name": name}
|
||||
if hook is not None:
|
||||
definition.update(type="filter", hook=hook, prio=priority, policy="accept")
|
||||
policy.append({"chain": definition})
|
||||
|
||||
def rule(name: str, *expressions: dict[str, Any]) -> None:
|
||||
policy.append({"rule": {**scope, "chain": name, "expr": list(expressions)}})
|
||||
|
||||
for hook in ("prerouting", "input", "forward", "output"):
|
||||
chain(hook, hook, -310 if hook == "prerouting" else 0)
|
||||
if not quarantine:
|
||||
for name in ("identity", "from_vm", "to_vm"):
|
||||
chain(name)
|
||||
for hook, interface, target in (
|
||||
("prerouting", "iifname", "identity"),
|
||||
("input", "iifname", "from_vm"),
|
||||
("forward", "iifname", "from_vm"),
|
||||
("forward", "oifname", "to_vm"),
|
||||
("output", "oifname", "to_vm"),
|
||||
):
|
||||
rule(hook, _match({"meta": {"key": interface}}, tap),
|
||||
{"drop": None} if quarantine else {"jump": {"target": target}})
|
||||
if quarantine:
|
||||
return policy
|
||||
|
||||
address = self._guest_ip(vm)
|
||||
mac = vm.mac.lower() if isinstance(vm.mac, str) else ""
|
||||
if (re.fullmatch(r"(?:[0-9a-f]{2}:){5}[0-9a-f]{2}", mac) is None
|
||||
or int(mac[:2], 16) & 1 or mac == "00:00:00:00:00:00"):
|
||||
raise ValidationError("firewall requires a nonzero unicast guest MAC")
|
||||
if not isinstance(ports, tuple):
|
||||
raise ValidationError("managed ports must be a tuple of TCP/HTTP/HTTPS port rules")
|
||||
allowed = set()
|
||||
for port_rule in ports:
|
||||
port = getattr(port_rule, "port", None)
|
||||
if (type(port) is not int or not 1 <= port <= 65535
|
||||
or getattr(port_rule, "protocol", None) not in ("TCP", "HTTP", "HTTPS")):
|
||||
raise ValidationError("private ports must be TCP/HTTP/HTTPS integers from 1 to 65535")
|
||||
allowed.add(port)
|
||||
# json_parse_set_expr() in nft 1.0.9 rejects [], even for an empty named
|
||||
# set. Omit elem, as set_print_json() does when listing an empty set.
|
||||
policy.insert(1, {"set": {**scope, "name": "tcp_ports", "type": "inet_service",
|
||||
"flags": ["constant"],
|
||||
**({"elem": sorted(allowed)} if allowed else {})}})
|
||||
|
||||
drop, success = {"drop": None}, {"return": None}
|
||||
ipv4 = _match(_payload("ether", "type"), "ip")
|
||||
arp = _match(_payload("ether", "type"), "arp")
|
||||
arp_header = [arp, _match(_payload("arp", "htype"), 1),
|
||||
_match(_payload("arp", "ptype"), "ip"),
|
||||
_match(_payload("arp", "hlen"), 6), _match(_payload("arp", "plen"), 4)]
|
||||
# Before conntrack (-200) and FDB learning: no MAC/IP/ARP spoofing,
|
||||
# IPv6, VLAN encapsulation or other EtherTypes from a managed port.
|
||||
rule("identity", _match(_payload("ether", "saddr"), mac, "!="), drop)
|
||||
rule("identity", ipv4, _match(_payload("ip", "saddr"), address), success)
|
||||
rule("identity", *arp_header,
|
||||
_match(_payload("arp", "operation"), {"set": ["request", "reply"]}),
|
||||
_match(_payload("arp", "saddr ether"), mac),
|
||||
_match(_payload("arp", "saddr ip"), address), success)
|
||||
# RFC 5227 address probes may use zero, but only probe this VM's IP.
|
||||
rule("identity", *arp_header, _match(_payload("arp", "operation"), "request"),
|
||||
_match(_payload("arp", "saddr ether"), mac),
|
||||
_match(_payload("arp", "saddr ip"), "0.0.0.0"),
|
||||
_match(_payload("arp", "daddr ip"), address), success)
|
||||
rule("identity", drop)
|
||||
|
||||
# Some link-local bridge frames take input without prerouting. Recheck
|
||||
# identity there too, before its local-finish callback can learn a MAC.
|
||||
rule("from_vm", {"jump": {"target": "identity"}})
|
||||
rule("from_vm", arp, success)
|
||||
rule("to_vm", *arp_header, _match(_payload("arp", "daddr ip"), address),
|
||||
_match(_payload("arp", "operation"), "request"), success)
|
||||
rule("to_vm", *arp_header, _match(_payload("arp", "daddr ip"), address),
|
||||
_match(_payload("arp", "daddr ether"), mac),
|
||||
_match(_payload("arp", "operation"), "reply"), success)
|
||||
|
||||
for name, outbound in (("from_vm", True), ("to_vm", False)):
|
||||
rule(name, _match(_payload("ether", "type"), "ip", "!="), drop)
|
||||
if not outbound:
|
||||
rule(name, ipv4, _match(_payload("ip", "daddr"), address, "!="), drop)
|
||||
rule(name, _match(_payload("ether", "daddr"), mac, "!="), drop)
|
||||
# Loose TCP tracking must not reclassify a server's midstream data
|
||||
# as a newly guest-initiated connection after tracking loss.
|
||||
rule(name, ipv4, _match(_payload("ip", "protocol"), "tcp"),
|
||||
_match(_ct("state"), "new", "in"),
|
||||
_match({"&": [_payload("tcp", "flags"), 23]}, 2, "!="), drop)
|
||||
|
||||
for client in (True, False):
|
||||
original = outbound == client
|
||||
flow = [_match(_ct("direction"), "original" if original else "reply"),
|
||||
_match(_ct("ip saddr" if client else "ip daddr", "original"), address)]
|
||||
states = ["new", "established"] if original else ["established"]
|
||||
state = _match(_ct("state"), states[0] if len(states) == 1 else states, "in")
|
||||
for protocol in (("tcp", "udp", "icmp") if client else ("tcp", "icmp")):
|
||||
parent = [*flow, _match(_ct("protocol"), protocol)]
|
||||
if not client and protocol == "tcp":
|
||||
parent.append(_match(_ct("proto-dst", "original"), "@tcp_ports"))
|
||||
packet = [ipv4, _match(_payload("ip", "protocol"), protocol)]
|
||||
if protocol == "icmp":
|
||||
packet.append(_match(_payload("icmp", "type"),
|
||||
"echo-request" if original else "echo-reply"))
|
||||
rule(name, *packet, *parent, state, success)
|
||||
# Related is restricted to essential ICMP errors and the
|
||||
# same authorized parent tuple, never TCP/UDP helper flows.
|
||||
rule(name, ipv4, _match(_payload("ip", "protocol"), "icmp"),
|
||||
_match(_payload("icmp", "type"), {"set": [
|
||||
"destination-unreachable", "time-exceeded", "parameter-problem",
|
||||
]}), *parent, _match(_ct("state"), "related", "in"), success)
|
||||
rule(name, drop)
|
||||
return policy
|
||||
|
||||
|
||||
def _normalize(objects: list[dict[str, Any]]) -> str:
|
||||
"""Canonical nft JSON, retaining every effective object, rule and verdict.
|
||||
|
||||
Ignore only handles, empty set presentation and nft's redundant protocol
|
||||
dependencies. Rule order is significant; pure conjunctions and sets are not.
|
||||
Unknown expressions/properties remain different rather than being ignored.
|
||||
"""
|
||||
def canonical(value: Any) -> Any:
|
||||
if isinstance(value, list):
|
||||
return [canonical(item) for item in value]
|
||||
if not isinstance(value, dict):
|
||||
return value
|
||||
value = {key: canonical(item) for key, item in value.items()}
|
||||
if (set(value) == {"|"} and isinstance(value["|"], list)
|
||||
and all(type(item) is int for item in value["|"])):
|
||||
result = 0
|
||||
for item in value["|"]:
|
||||
result |= item
|
||||
return result
|
||||
if set(value) == {"set"} and isinstance(value["set"], list):
|
||||
value["set"] = sorted(value["set"], key=lambda item: json.dumps(item, sort_keys=True))
|
||||
return value
|
||||
|
||||
def bitmask(value: Any, names: dict[str, int]) -> Any:
|
||||
if isinstance(value, str):
|
||||
return names.get(value, value)
|
||||
if isinstance(value, dict) and set(value) == {"|"}:
|
||||
value = value["|"]
|
||||
if isinstance(value, list):
|
||||
bits = [bitmask(item, names) for item in value]
|
||||
if all(type(item) is int for item in bits):
|
||||
result = 0
|
||||
for item in bits:
|
||||
result |= item
|
||||
return result
|
||||
return value
|
||||
|
||||
definitions, rules = [], {}
|
||||
for item in objects:
|
||||
kind, raw = next(iter(item.items()))
|
||||
if kind == "metainfo":
|
||||
continue
|
||||
obj = {key: canonical(value) for key, value in raw.items() if key != "handle"}
|
||||
if kind == "set":
|
||||
elements = obj.get("elem", [])
|
||||
if not isinstance(elements, list):
|
||||
elements = [elements]
|
||||
obj["elem"] = sorted(elements, key=lambda value: json.dumps(value, sort_keys=True))
|
||||
if obj.get("flags") == []:
|
||||
del obj["flags"]
|
||||
elif isinstance(obj.get("flags"), str):
|
||||
obj["flags"] = [obj["flags"]]
|
||||
if kind != "rule":
|
||||
definitions.append({kind: obj})
|
||||
continue
|
||||
|
||||
expressions = obj.get("expr", [])
|
||||
if not isinstance(expressions, list) or not isinstance(obj.get("chain"), str):
|
||||
raise UvmError("invalid nft rule snapshot")
|
||||
tcp_flags = {"fin": 1, "syn": 2, "rst": 4, "psh": 8, "ack": 16,
|
||||
"urg": 32, "ecn": 64, "cwr": 128}
|
||||
for expression in expressions:
|
||||
if not isinstance(expression, dict) or not isinstance(expression.get("match", {}), dict):
|
||||
continue
|
||||
match = expression.get("match", {})
|
||||
left = match.get("left")
|
||||
if match and not {"left", "right", "op"}.issubset(match):
|
||||
raise UvmError("invalid nft match snapshot")
|
||||
right = match.get("right")
|
||||
if left in (_payload("ip", "protocol"), _ct("protocol")) and type(right) is int:
|
||||
match["right"] = {1: "icmp", 6: "tcp", 17: "udp"}.get(right, right)
|
||||
if match.get("op") == "in" and (
|
||||
(isinstance(right, str) and right.startswith("@"))
|
||||
or (isinstance(right, dict) and set(right) == {"set"})
|
||||
):
|
||||
match["op"] = "=="
|
||||
if left == _ct("state"):
|
||||
match["right"] = bitmask(match["right"], {
|
||||
"invalid": 1, "established": 2, "related": 4, "new": 8, "untracked": 64,
|
||||
})
|
||||
if (isinstance(left, dict) and isinstance(left.get("&"), list)
|
||||
and len(left["&"]) == 2 and left["&"][0] == _payload("tcp", "flags")):
|
||||
left["&"][1] = bitmask(left["&"][1], tcp_flags)
|
||||
match["right"] = bitmask(match["right"], tcp_flags)
|
||||
|
||||
# nft's replayable JSON omits dependencies implied by named payloads.
|
||||
encoded = json.dumps(expressions, sort_keys=True)
|
||||
has_tcp = '"protocol": "tcp"' in encoded
|
||||
has_icmp = '"protocol": "icmp"' in encoded
|
||||
expressions = [expr for expr in expressions if not (
|
||||
(has_tcp and expr == _match(_payload("ip", "protocol"), "tcp"))
|
||||
or (has_icmp and expr == _match(_payload("ip", "protocol"), "icmp"))
|
||||
)]
|
||||
encoded = json.dumps(expressions, sort_keys=True)
|
||||
expressions = [expr for expr in expressions if not (
|
||||
('"protocol": "arp"' in encoded and expr == _match(_payload("ether", "type"), "arp"))
|
||||
or (('"protocol": "ip"' in encoded or has_icmp)
|
||||
and expr == _match(_payload("ether", "type"), "ip"))
|
||||
)]
|
||||
count = len(expressions)
|
||||
if expressions and (not isinstance(expressions[-1], dict) or set(expressions[-1]) != {"match"}):
|
||||
count -= 1
|
||||
if all(isinstance(expr, dict) and set(expr) == {"match"} for expr in expressions[:count]):
|
||||
expressions = sorted(expressions[:count], key=lambda expr: json.dumps(expr, sort_keys=True)) + expressions[count:]
|
||||
obj["expr"] = expressions
|
||||
rules.setdefault(obj.get("chain", ""), []).append(obj)
|
||||
definitions.sort(key=lambda item: json.dumps(item, sort_keys=True))
|
||||
return json.dumps([definitions, rules], sort_keys=True, separators=(",", ":"))
|
||||
Reference in New Issue
Block a user