lix/flake.nix
alois31 127ee1a101
libstore/build: use an allowlist approach to syscall filtering
Previously, system call filtering (to prevent builders from storing files with
setuid/setgid permission bits or extended attributes) was performed using a
blocklist. While this looks simple at first, it actually carries significant
security and maintainability risks: after all, the kernel may add new syscalls
to achieve the same functionality one is trying to block, and it can even be
hard to actually add the syscall to the blocklist when building against a C
library that doesn't know about it yet. For a recent demonstration of this
happening in practice to Nix, see the introduction of fchmodat2 [0] [1].

The allowlist approach does not share the same drawback. While it does require
a rather large list of harmless syscalls to be maintained in the codebase,
failing to update this list (and roll out the update to all users) in time has
rather benign effects; at worst, very recent programs that already rely on new
syscalls will fail with an error the same way they would on a slightly older
kernel that doesn't support them yet. Most importantly, no unintended new ways
of performing dangerous operations will be silently allowed.

Another possible drawback is reduced system call performance due to the larger
filter created by the allowlist requiring more computation [2]. However, this
issue has not convincingly been demonstrated yet in practice, for example in
systemd or various browsers. To the contrary, it has been measured that the the
actual filter constructed here has approximately the same overhead as a very
simple filter blocking only one system call.

This commit tries to keep the behavior as close to unchanged as possible. The
system call list is in line with libseccomp 2.5.5 and glibc 2.39, which are the
latest versions at the point of writing. Since libseccomp 2.5.5 is already a
requirement and the distributions shipping this together with older versions of
glibc are mostly not a thing any more, this should not lead to more build
failures any more.

[0] https://github.com/NixOS/nixpkgs/issues/300635
[1] https://github.com/NixOS/nix/issues/10424
[2] https://github.com/flatpak/flatpak/pull/4462#issuecomment-1061690607

Change-Id: I541be3ea9b249bcceddfed6a5a13ac10b11e16ad
2024-07-25 18:24:40 +02:00

446 lines
15 KiB
Nix
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{
description = "The purely functional package manager";
inputs = {
nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.05-small";
nixpkgs-regression.url = "github:NixOS/nixpkgs/215d4d0fd80ca5163643b03a33fde804a29cc1e2";
pre-commit-hooks = {
url = "github:cachix/git-hooks.nix";
flake = false;
};
nix2container = {
url = "github:nlewo/nix2container";
flake = false;
};
flake-compat = {
url = "github:edolstra/flake-compat";
flake = false;
};
};
outputs =
{
self,
nixpkgs,
nixpkgs-regression,
pre-commit-hooks,
nix2container,
flake-compat,
}:
let
inherit (nixpkgs) lib;
# This notice gets echoed as a dev shell hook, and can be turned off with
# `touch .nocontribmsg`
sgr = ''['';
freezePage = "https://wiki.lix.systems/books/lix-contributors/page/freezes-and-recommended-contributions";
codebaseOverview = "https://wiki.lix.systems/books/lix-contributors/page/codebase-overview";
contribNotice = builtins.toFile "lix-contrib-notice" ''
Hey there!
If you're thinking of working on Lix, please consider talking to us about it!
You should be aware that we are ${sgr}1mnot${sgr}0m accepting major features without some conditions,
and we highly recommend looking at our freeze status page on the wiki:
${sgr}32m${freezePage}${sgr}0m
We also have an overview of the codebase at
${sgr}32m${codebaseOverview}${sgr}0m,
and other helpful information on the wiki.
But above all else, ${sgr}1mwe want to hear from you!${sgr}0m
We can help you figure out where in the codebase to look for whatever you want to do,
and we'd like to work together with all contributors as much as possible.
Lix is a collaborative project :)
You can open an issue at https://git.lix.systems/lix-project/lix/issues
or chat with us on Matrix: #space:lix.systems.
(Run `touch .nocontribmsg` to hide this message.)
'';
officialRelease = false;
# Set to true to build the release notes for the next release.
buildUnreleasedNotes = true;
versionSuffix =
if officialRelease then
""
else
"pre${
builtins.substring 0 8 (self.lastModifiedDate or self.lastModified or "19700101")
}_${self.shortRev or "dirty"}";
linux32BitSystems = [ "i686-linux" ];
linux64BitSystems = [
"x86_64-linux"
"aarch64-linux"
];
linuxSystems = linux32BitSystems ++ linux64BitSystems;
darwinSystems = [
"x86_64-darwin"
"aarch64-darwin"
];
systems = linuxSystems ++ darwinSystems;
# If you add something here, please update the list in doc/manual/src/contributing/hacking.md.
# Thanks~
crossSystems = [
"armv6l-linux"
"armv7l-linux"
"riscv64-linux"
"aarch64-linux"
# FIXME: still broken in 24.05: fails to build rustc(??) due to missing -lstdc++ dep
# "x86_64-freebsd"
# FIXME: broken dev shell due to python
# "x86_64-netbsd"
];
stdenvs = [
"gccStdenv"
"clangStdenv"
"stdenv"
"libcxxStdenv"
"ccacheStdenv"
];
forAllSystems = lib.genAttrs systems;
# Same as forAllSystems, but removes nulls, in case something is broken
# on that system.
forAvailableSystems =
f: lib.filterAttrs (name: value: value != null && value != { }) (forAllSystems f);
forAllCrossSystems = lib.genAttrs crossSystems;
forAllStdenvs =
f:
lib.listToAttrs (
map (stdenvName: {
name = "${stdenvName}Packages";
value = f stdenvName;
}) stdenvs
);
# Memoize nixpkgs for different platforms for efficiency.
nixpkgsFor = forAllSystems (
system:
let
make-pkgs =
crossSystem: stdenv:
import nixpkgs {
localSystem = {
inherit system;
};
crossSystem =
if crossSystem == null then
null
else
{
system = crossSystem;
}
// lib.optionalAttrs (crossSystem == "x86_64-freebsd") { useLLVM = true; };
overlays = [ (overlayFor (p: p.${stdenv})) ];
};
stdenvs = forAllStdenvs (make-pkgs null);
native = stdenvs.stdenvPackages;
in
{
inherit stdenvs native;
static = native.pkgsStatic;
cross = forAllCrossSystems (crossSystem: make-pkgs crossSystem "stdenv");
}
);
overlayFor =
getStdenv: final: prev:
let
currentStdenv = getStdenv final;
in
{
nixStable = prev.nix;
# Forward from the previous stage as we dont want it to pick the lowdown override
nixUnstable = prev.nixUnstable;
check-headers = final.buildPackages.callPackage ./maintainers/check-headers.nix { };
check-syscalls = final.buildPackages.callPackage ./maintainers/check-syscalls.nix { };
default-busybox-sandbox-shell = final.busybox.override {
useMusl = true;
enableStatic = true;
enableMinimal = true;
extraConfig = ''
CONFIG_FEATURE_FANCY_ECHO y
CONFIG_FEATURE_SH_MATH y
CONFIG_FEATURE_SH_MATH_64 y
CONFIG_ASH y
CONFIG_ASH_OPTIMIZE_FOR_SIZE y
CONFIG_ASH_ALIAS y
CONFIG_ASH_BASH_COMPAT y
CONFIG_ASH_CMDCMD y
CONFIG_ASH_ECHO y
CONFIG_ASH_GETOPTS y
CONFIG_ASH_INTERNAL_GLOB y
CONFIG_ASH_JOB_CONTROL y
CONFIG_ASH_PRINTF y
CONFIG_ASH_TEST y
'';
};
nix = final.callPackage ./package.nix {
inherit versionSuffix officialRelease;
stdenv = currentStdenv;
busybox-sandbox-shell = final.busybox-sandbox-shell or final.default-busybox-sandbox-shell;
};
pegtl = final.nix.passthru.pegtl;
# Export the patched version of boehmgc that Lix uses into the overlay
# for consumers of this flake.
boehmgc-nix = final.nix.passthru.boehmgc-nix;
# And same thing for our build-release-notes package.
build-release-notes = final.nix.passthru.build-release-notes;
};
in
{
# for repl debugging
inherit self;
# A Nixpkgs overlay that overrides the 'nix' and
# 'nix.perl-bindings' packages.
overlays.default = overlayFor (p: p.stdenv);
hydraJobs = {
# Binary package for various platforms.
build = forAllSystems (system: self.packages.${system}.nix);
devShell = forAllSystems (system: {
default = self.devShells.${system}.default;
clang = self.devShells.${system}.native-clangStdenvPackages;
});
rl-next = forAllSystems (
system:
let
rl-next-check =
name: dir:
let
pkgs = nixpkgsFor.${system}.native;
in
pkgs.buildPackages.runCommand "test-${name}-release-notes" { } ''
LANG=C.UTF-8 ${lib.getExe pkgs.build-release-notes} --change-authors ${./doc/manual/change-authors.yml} ${dir} >$out
'';
in
{
user = rl-next-check "rl-next" ./doc/manual/rl-next;
}
);
# Completion tests for the Nix REPL.
repl-completion = forAllSystems (
system: nixpkgsFor.${system}.native.callPackage ./tests/repl-completion.nix { }
);
# Perl bindings for various platforms.
perlBindings = forAllSystems (system: nixpkgsFor.${system}.native.nix.passthru.perl-bindings);
# Binary tarball for various platforms, containing a Nix store
# with the closure of 'nix' package.
binaryTarball = forAllSystems (system: nixpkgsFor.${system}.native.nix.passthru.binaryTarball);
# docker image with Lix inside
dockerImage = lib.genAttrs linux64BitSystems (system: self.packages.${system}.dockerImage);
# API docs for Nix's unstable internal C++ interfaces.
internal-api-docs =
let
nixpkgs = nixpkgsFor.x86_64-linux.native;
inherit (nixpkgs) pkgs;
nix = pkgs.callPackage ./package.nix {
inherit versionSuffix officialRelease buildUnreleasedNotes;
inherit (pkgs) build-release-notes;
internalApiDocs = true;
busybox-sandbox-shell = pkgs.busybox-sandbox-shell;
};
in
nix.overrideAttrs (prev: {
# This Hydra job is just for the internal API docs.
# We don't need the build artifacts here.
dontBuild = true;
doCheck = false;
doInstallCheck = false;
});
# System tests.
tests = import ./tests/nixos { inherit lib nixpkgs nixpkgsFor; } // {
# Make sure that nix-env still produces the exact same result
# on a particular version of Nixpkgs.
evalNixpkgs =
with nixpkgsFor.x86_64-linux.native;
runCommand "eval-nixos" { buildInputs = [ nix ]; } ''
type -p nix-env
# Note: we're filtering out nixos-install-tools because https://github.com/NixOS/nixpkgs/pull/153594#issuecomment-1020530593.
time nix-env --store dummy:// -f ${nixpkgs-regression} -qaP --drv-path | sort | grep -v nixos-install-tools > packages
[[ $(sha1sum < packages | cut -c1-40) = 402242fca90874112b34718b8199d844e8b03d12 ]]
mkdir $out
'';
nixpkgsLibTests = forAllSystems (
system:
let
inherit (self.packages.${system}) nix;
pkgs = nixpkgsFor.${system}.native;
testWithNix = import (nixpkgs + "/lib/tests/test-with-nix.nix") { inherit pkgs lib nix; };
in
pkgs.symlinkJoin {
name = "nixpkgs-lib-tests";
paths =
[ testWithNix ]
# FIXME: This is disabled on darwin due to a nixpkgs bug https://github.com/NixOS/nixpkgs/issues/319147
# After that is fixed, it should be restored to use lib/tests/release.nix as before, rather than this reimplementation.
++ lib.optionals pkgs.stdenv.isLinux [
(import (nixpkgs + "/pkgs/test/release") { inherit pkgs lib nix; })
];
}
);
};
pre-commit = forAvailableSystems (
system:
let
pkgs = nixpkgsFor.${system}.native;
pre-commit-check = import ./misc/pre-commit.nix { inherit self pkgs pre-commit-hooks; };
# dotnet-sdk_6, a nativeBuildInputs of pre-commit, is broken on i686-linux.
available = lib.meta.availableOn { inherit system; } pkgs.dotnet-sdk_6;
in
lib.optionalAttrs available pre-commit-check
);
};
release-jobs = import ./releng/release-jobs.nix {
inherit (self) hydraJobs;
pkgs = nixpkgsFor.x86_64-linux.native;
};
releaseTests = lib.foldl lib.recursiveUpdate { } [
(lib.genAttrs (linux64BitSystems ++ darwinSystems) (system: {
nativeBuild = self.packages.${system}.nix;
}))
(lib.genAttrs (linux64BitSystems) (system: {
staticBuild = self.packages.${system}.nix-static;
}))
{
x86_64-linux = {
# TODO add more cross/static release targets?
crossBuild.aarch64-linux = self.packages.x86_64-linux.nix-aarch64-linux;
# TODO wire up a nixos installer test with that lix and
# run it, once nixpkgs can actually do that (again). :/
# # nix build .#nixosTests.installer.{btrfsSimple,luksroot,lvm,simple,switchToFlake}
};
}
];
# NOTE *do not* add fresh derivations to checks, always add them to
# hydraJobs first (so CI will pick them up) and only link them here
checks = forAvailableSystems (
system:
{
# devShells and packages already get checked by nix flake check, so
# this is just jobs that are special
binaryTarball = self.hydraJobs.binaryTarball.${system};
perlBindings = self.hydraJobs.perlBindings.${system};
nixpkgsLibTests = self.hydraJobs.tests.nixpkgsLibTests.${system};
rl-next = self.hydraJobs.rl-next.${system}.user;
# Will be empty attr set on i686-linux, and filtered out by forAvailableSystems.
pre-commit = self.hydraJobs.pre-commit.${system};
repl-completion = self.hydraJobs.repl-completion.${system};
}
// (lib.optionalAttrs (builtins.elem system linux64BitSystems)) {
dockerImage = self.hydraJobs.dockerImage.${system};
}
);
packages = forAllSystems (
system:
rec {
inherit (nixpkgsFor.${system}.native) nix;
default = nix;
}
// (
lib.optionalAttrs (builtins.elem system linux64BitSystems) {
nix-static = nixpkgsFor.${system}.static.nix;
dockerImage =
let
pkgs = nixpkgsFor.${system}.native;
nix2container' = import nix2container { inherit pkgs system; };
in
import ./docker.nix {
inherit pkgs;
nix2container = nix2container'.nix2container;
tag = pkgs.nix.version;
};
}
// builtins.listToAttrs (
map (crossSystem: {
name = "nix-${crossSystem}";
value = nixpkgsFor.${system}.cross.${crossSystem}.nix;
}) crossSystems
)
// builtins.listToAttrs (
map (stdenvName: {
name = "nix-${stdenvName}";
value = nixpkgsFor.${system}.stdenvs."${stdenvName}Packages".nix;
}) stdenvs
)
)
);
devShells =
let
makeShell =
pkgs: stdenv:
let
nix = pkgs.callPackage ./package.nix {
inherit stdenv officialRelease versionSuffix;
busybox-sandbox-shell = pkgs.busybox-sandbox-shell or pkgs.default-busybox-sandbox;
internalApiDocs = false;
};
pre-commit = self.hydraJobs.pre-commit.${pkgs.system} or { };
in
pkgs.callPackage nix.mkDevShell {
pre-commit-checks = pre-commit;
inherit contribNotice;
};
in
forAllSystems (
system:
let
makeShells =
prefix: pkgs:
lib.mapAttrs' (k: v: lib.nameValuePair "${prefix}-${k}" v) (
forAllStdenvs (stdenvName: makeShell pkgs pkgs.${stdenvName})
);
in
(makeShells "native" nixpkgsFor.${system}.native)
// (makeShells "static" nixpkgsFor.${system}.static)
// (forAllCrossSystems (
crossSystem:
let
pkgs = nixpkgsFor.${system}.cross.${crossSystem};
in
makeShell pkgs pkgs.stdenv
))
// {
default = self.devShells.${system}.native-clangStdenvPackages;
}
);
};
}