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#! /usr/bin/env nix-shell
#! nix-shell -i python -p "python38.withPackages (ps: [ps.PyGithub])" git gnupg
# This is automatically called by ../update.sh.
from __future__ import annotations
import json
import os
import re
import subprocess
import sys
from dataclasses import dataclass
from pathlib import Path
from tempfile import TemporaryDirectory
from typing import (
Dict,
Iterator,
List,
Optional,
Sequence,
Tuple,
TypedDict,
Union,
)
from github import Github
from github.GitRelease import GitRelease
VersionComponent = Union[int, str]
Version = List[VersionComponent]
PatchData = TypedDict("PatchData", {"name": str, "url": str, "sha256": str, "extra": str})
Patch = TypedDict("Patch", {
"patch": PatchData,
"version": str,
"sha256": str,
})
@dataclass
class ReleaseInfo:
version: Version
release: GitRelease
HERE = Path(__file__).resolve().parent
NIXPKGS_KERNEL_PATH = HERE.parent
NIXPKGS_PATH = HERE.parents[4]
HARDENED_GITHUB_REPO = "anthraxx/linux-hardened"
HARDENED_TRUSTED_KEY = HERE / "anthraxx.asc"
HARDENED_PATCHES_PATH = HERE / "patches.json"
MIN_KERNEL_VERSION: Version = [4, 14]
def run(*args: Union[str, Path]) -> subprocess.CompletedProcess[bytes]:
try:
return subprocess.run(
args,
check=True,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE,
encoding="utf-8",
)
except subprocess.CalledProcessError as err:
print(
f"error: `{err.cmd}` failed unexpectedly\n"
f"status code: {err.returncode}\n"
f"stdout:\n{err.stdout.strip()}\n"
f"stderr:\n{err.stderr.strip()}",
file=sys.stderr,
)
sys.exit(1)
def nix_prefetch_url(url: str) -> Tuple[str, Path]:
output = run("nix-prefetch-url", "--print-path", url).stdout
sha256, path = output.strip().split("\n")
return sha256, Path(path)
def verify_openpgp_signature(
*, name: str, trusted_key: Path, sig_path: Path, data_path: Path,
) -> bool:
with TemporaryDirectory(suffix=".nixpkgs-gnupg-home") as gnupg_home_str:
gnupg_home = Path(gnupg_home_str)
run("gpg", "--homedir", gnupg_home, "--import", trusted_key)
keyring = gnupg_home / "pubring.kbx"
try:
subprocess.run(
("gpgv", "--keyring", keyring, sig_path, data_path),
check=True,
stderr=subprocess.PIPE,
encoding="utf-8",
)
return True
except subprocess.CalledProcessError as err:
print(
f"error: signature for {name} failed to verify!",
file=sys.stderr,
)
print(err.stderr, file=sys.stderr, end="")
return False
def fetch_patch(*, name: str, release_info: ReleaseInfo) -> Optional[Patch]:
release = release_info.release
extra = f'-{release_info.version[-1]}'
def find_asset(filename: str) -> str:
try:
it: Iterator[str] = (
asset.browser_download_url
for asset in release.get_assets()
if asset.name == filename
)
return next(it)
except StopIteration:
raise KeyError(filename)
patch_filename = f"{name}.patch"
try:
patch_url = find_asset(patch_filename)
sig_url = find_asset(patch_filename + ".sig")
except KeyError:
print(f"error: {patch_filename}{{,.sig}} not present", file=sys.stderr)
return None
sha256, patch_path = nix_prefetch_url(patch_url)
_, sig_path = nix_prefetch_url(sig_url)
sig_ok = verify_openpgp_signature(
name=name,
trusted_key=HARDENED_TRUSTED_KEY,
sig_path=sig_path,
data_path=patch_path,
)
if not sig_ok:
return None
kernel_ver = release_info.release.tag_name.replace("-hardened1", "")
major = kernel_ver.split('.')[0]
sha256_kernel, _ = nix_prefetch_url(f"mirror://kernel/linux/kernel/v{major}.x/linux-{kernel_ver}.tar.xz")
return Patch(
patch=PatchData(name=patch_filename, url=patch_url, sha256=sha256, extra=extra),
version=kernel_ver,
sha256=sha256_kernel
)
def parse_version(version_str: str) -> Version:
version: Version = []
for component in re.split('\.|\-', version_str):
try:
version.append(int(component))
except ValueError:
version.append(component)
return version
def version_string(version: Version) -> str:
return ".".join(str(component) for component in version)
def major_kernel_version_key(kernel_version: Version) -> str:
return version_string(kernel_version[:-1])
def commit_patches(*, kernel_key: str, message: str) -> None:
new_patches_path = HARDENED_PATCHES_PATH.with_suffix(".new")
with open(new_patches_path, "w") as new_patches_file:
json.dump(patches, new_patches_file, indent=4, sort_keys=True)
new_patches_file.write("\n")
os.rename(new_patches_path, HARDENED_PATCHES_PATH)
message = f"linux/hardened/patches/{kernel_key}: {message}"
print(message)
if os.environ.get("COMMIT"):
run(
"git",
"-C",
NIXPKGS_PATH,
"commit",
f"--message={message}",
HARDENED_PATCHES_PATH,
)
# Load the existing patches.
patches: Dict[str, Patch]
with open(HARDENED_PATCHES_PATH) as patches_file:
patches = json.load(patches_file)
# Get the set of currently packaged kernel versions.
kernel_versions = {}
for filename in os.listdir(NIXPKGS_KERNEL_PATH):
filename_match = re.fullmatch(r"linux-(\d+)\.(\d+)\.nix", filename)
if filename_match:
nix_version_expr = f"""
with import {NIXPKGS_PATH} {{}};
(callPackage {NIXPKGS_KERNEL_PATH / filename} {{}}).version
"""
kernel_version_json = run(
"nix-instantiate", "--eval", "--json", "--expr", nix_version_expr,
).stdout
kernel_version = parse_version(json.loads(kernel_version_json))
if kernel_version < MIN_KERNEL_VERSION:
continue
kernel_key = major_kernel_version_key(kernel_version)
kernel_versions[kernel_key] = kernel_version
# Remove patches for unpackaged kernel versions.
for kernel_key in sorted(patches.keys() - kernel_versions.keys()):
commit_patches(kernel_key=kernel_key, message="remove")
g = Github(os.environ.get("GITHUB_TOKEN"))
repo = g.get_repo(HARDENED_GITHUB_REPO)
failures = False
# Match each kernel version with the best patch version.
releases = {}
for release in repo.get_releases():
version = parse_version(release.tag_name)
# needs to look like e.g. 5.6.3-hardened1
if len(version) < 4:
continue
kernel_version = version[:-1]
kernel_key = major_kernel_version_key(kernel_version)
try:
packaged_kernel_version = kernel_versions[kernel_key]
except KeyError:
continue
release_info = ReleaseInfo(version=version, release=release)
if kernel_version == packaged_kernel_version:
releases[kernel_key] = release_info
else:
# Fall back to the latest patch for this major kernel version,
# skipping patches for kernels newer than the packaged one.
if '.'.join(str(x) for x in kernel_version) > '.'.join(str(x) for x in packaged_kernel_version):
continue
elif (
kernel_key not in releases or releases[kernel_key].version < version
):
releases[kernel_key] = release_info
# Update hardened-patches.json for each release.
for kernel_key in sorted(releases.keys()):
release_info = releases[kernel_key]
release = release_info.release
version = release_info.version
version_str = release.tag_name
name = f"linux-hardened-{version_str}"
old_version: Optional[Version] = None
old_version_str: Optional[str] = None
update: bool
try:
old_filename = patches[kernel_key]["patch"]["name"]
old_version_str = old_filename.replace("linux-hardened-", "").replace(
".patch", ""
)
old_version = parse_version(old_version_str)
update = old_version < version
except KeyError:
update = True
if update:
patch = fetch_patch(name=name, release_info=release_info)
if patch is None:
failures = True
else:
patches[kernel_key] = patch
if old_version:
message = f"{old_version_str} -> {version_str}"
else:
message = f"init at {version_str}"
commit_patches(kernel_key=kernel_key, message=message)
missing_kernel_versions = kernel_versions.keys() - patches.keys()
if missing_kernel_versions:
print(
f"warning: no patches for kernel versions "
+ ", ".join(missing_kernel_versions),
file=sys.stderr,
)
if failures:
sys.exit(1)