lix/package.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

538 lines
16 KiB
Nix

{
pkgs,
lib,
stdenv,
aws-sdk-cpp,
# If the patched version of Boehm isn't passed, then patch it based off of
# pkgs.boehmgc. This allows `callPackage`ing this file without needing to
# to implement behavior that this package flat out doesn't build without
# anyway, but also allows easily overriding the patch logic.
boehmgc-nix ? __forDefaults.boehmgc-nix,
boehmgc,
nlohmann_json,
build-release-notes ? __forDefaults.build-release-notes,
boost,
brotli,
bzip2,
callPackage,
cmake,
curl,
doxygen,
editline-lix ? __forDefaults.editline-lix,
editline,
git,
gtest,
jq,
libarchive,
libcpuid,
libseccomp,
libsodium,
lsof,
lowdown,
mdbook,
mdbook-linkcheck,
mercurial,
meson,
ninja,
openssl,
pegtl ? __forDefaults.pegtl,
pkg-config,
python3,
rapidcheck,
sqlite,
toml11,
util-linuxMinimal ? utillinuxMinimal,
utillinuxMinimal ? null,
xz,
busybox-sandbox-shell,
# internal fork of nix-doc providing :doc in the repl
lix-doc ? __forDefaults.lix-doc,
pname ? "lix",
versionSuffix ? "",
officialRelease ? false,
# Set to true to build the release notes for the next release.
buildUnreleasedNotes ? true,
internalApiDocs ? false,
# Not a real argument, just the only way to approximate let-binding some
# stuff for argument defaults.
__forDefaults ? {
canRunInstalled = stdenv.buildPlatform.canExecute stdenv.hostPlatform;
boehmgc-nix = boehmgc.override { enableLargeConfig = true; };
editline-lix = editline.overrideAttrs (prev: {
configureFlags = prev.configureFlags or [ ] ++ [ (lib.enableFeature true "sigstop") ];
});
lix-doc = callPackage ./lix-doc/package.nix { };
build-release-notes = callPackage ./maintainers/build-release-notes.nix { };
pegtl = callPackage ./misc/pegtl.nix { };
},
}:
let
inherit (__forDefaults) canRunInstalled;
inherit (lib) fileset;
inherit (stdenv) hostPlatform buildPlatform;
versionJson = builtins.fromJSON (builtins.readFile ./version.json);
version = versionJson.version + versionSuffix;
aws-sdk-cpp-nix = aws-sdk-cpp.override {
apis = [
"s3"
"transfer"
];
customMemoryManagement = false;
};
# Reimplementation of Nixpkgs' Meson cross file, with some additions to make
# it actually work.
mesonCrossFile =
let
cpuFamily =
platform:
with platform;
if isAarch32 then
"arm"
else if isx86_32 then
"x86"
else
platform.uname.processor;
in
builtins.toFile "lix-cross-file.conf" ''
[properties]
# Meson is convinced that if !buildPlatform.canExecute hostPlatform then we cannot
# build anything at all, which is not at all correct. If we can't execute the host
# platform, we'll just disable tests and doc gen.
needs_exe_wrapper = false
[binaries]
# Meson refuses to consider any CMake binary during cross compilation if it's
# not explicitly specified here, in the cross file.
# https://github.com/mesonbuild/meson/blob/0ed78cf6fa6d87c0738f67ae43525e661b50a8a2/mesonbuild/cmake/executor.py#L72
cmake = 'cmake'
'';
# The internal API docs need these for the build, but if we're not building
# Nix itself, then these don't need to be propagated.
maybePropagatedInputs = [
boehmgc-nix
nlohmann_json
];
# .gitignore has already been processed, so any changes in it are irrelevant
# at this point. It is not represented verbatim for test purposes because
# that would interfere with repo semantics.
baseFiles = fileset.fileFilter (f: f.name != ".gitignore") ./.;
configureFiles = fileset.unions [ ./version.json ];
topLevelBuildFiles = fileset.unions ([
./meson.build
./meson.options
./meson
./scripts/meson.build
./subprojects
]);
functionalTestFiles = fileset.unions [
./tests/functional
./tests/unit
(fileset.fileFilter (f: lib.strings.hasPrefix "nix-profile" f.name) ./scripts)
];
in
stdenv.mkDerivation (finalAttrs: {
inherit pname version;
src = fileset.toSource {
root = ./.;
fileset = fileset.intersection baseFiles (
fileset.unions (
[
configureFiles
topLevelBuildFiles
functionalTestFiles
]
++ lib.optionals (!finalAttrs.dontBuild || internalApiDocs) [
./doc
./misc
./src
./COPYING
]
)
);
};
VERSION_SUFFIX = versionSuffix;
outputs =
[ "out" ]
++ lib.optionals (!finalAttrs.dontBuild) [
"dev"
"doc"
];
dontBuild = false;
mesonFlags =
lib.optionals hostPlatform.isLinux [
# You'd think meson could just find this in PATH, but busybox is in buildInputs,
# which don't actually get added to PATH. And buildInputs is correct over
# nativeBuildInputs since this should be a busybox executable on the host.
"-Dsandbox-shell=${lib.getExe' busybox-sandbox-shell "busybox"}"
]
++ lib.optional hostPlatform.isStatic "-Denable-embedded-sandbox-shell=true"
++ lib.optional (finalAttrs.dontBuild) "-Denable-build=false"
++ [
# mesonConfigurePhase automatically passes -Dauto_features=enabled,
# so we must explicitly enable or disable features that we are not passing
# dependencies for.
(lib.mesonEnable "internal-api-docs" internalApiDocs)
(lib.mesonBool "enable-tests" finalAttrs.finalPackage.doCheck)
(lib.mesonBool "enable-docs" canRunInstalled)
]
++ lib.optional (hostPlatform != buildPlatform) "--cross-file=${mesonCrossFile}";
# We only include CMake so that Meson can locate toml11, which only ships CMake dependency metadata.
dontUseCmakeConfigure = true;
nativeBuildInputs =
[
python3
meson
ninja
cmake
]
++ [
(lib.getBin lowdown)
mdbook
mdbook-linkcheck
]
++ [
pkg-config
# Tests
git
mercurial
jq
lsof
]
++ lib.optional hostPlatform.isLinux util-linuxMinimal
++ lib.optional (!officialRelease && buildUnreleasedNotes) build-release-notes
++ lib.optional internalApiDocs doxygen;
buildInputs =
[
curl
bzip2
xz
brotli
editline-lix
openssl
sqlite
libarchive
boost
lowdown
libsodium
toml11
lix-doc
pegtl
]
++ lib.optionals hostPlatform.isLinux [
libseccomp
busybox-sandbox-shell
]
++ lib.optional internalApiDocs rapidcheck
++ lib.optional hostPlatform.isx86_64 libcpuid
# There have been issues building these dependencies
++ lib.optional (hostPlatform.canExecute buildPlatform) aws-sdk-cpp-nix
++ lib.optionals (finalAttrs.dontBuild) maybePropagatedInputs;
checkInputs = [
gtest
rapidcheck
];
propagatedBuildInputs = lib.optionals (!finalAttrs.dontBuild) maybePropagatedInputs;
disallowedReferences = [ boost ];
# Needed for Meson to find Boost.
# https://github.com/NixOS/nixpkgs/issues/86131.
env = {
BOOST_INCLUDEDIR = "${lib.getDev boost}/include";
BOOST_LIBRARYDIR = "${lib.getLib boost}/lib";
};
preConfigure =
lib.optionalString (!finalAttrs.dontBuild && !hostPlatform.isStatic) ''
# Copy libboost_context so we don't get all of Boost in our closure.
# https://github.com/NixOS/nixpkgs/issues/45462
mkdir -p $out/lib
cp -pd ${boost}/lib/{libboost_context*,libboost_thread*,libboost_system*} $out/lib
rm -f $out/lib/*.a
''
+ lib.optionalString (!finalAttrs.dontBuild && hostPlatform.isLinux && !hostPlatform.isStatic) ''
chmod u+w $out/lib/*.so.*
patchelf --set-rpath $out/lib:${stdenv.cc.cc.lib}/lib $out/lib/libboost_thread.so.*
''
+ lib.optionalString (!finalAttrs.dontBuild && hostPlatform.isDarwin) ''
for LIB in $out/lib/*.dylib; do
chmod u+w $LIB
install_name_tool -id $LIB $LIB
install_name_tool -delete_rpath ${boost}/lib/ $LIB || true
done
install_name_tool -change ${boost}/lib/libboost_system.dylib $out/lib/libboost_system.dylib $out/lib/libboost_thread.dylib
''
+ ''
# Workaround https://github.com/NixOS/nixpkgs/issues/294890.
if [[ -n "''${doCheck:-}" ]]; then
appendToVar configureFlags "--enable-tests"
else
appendToVar configureFlags "--disable-tests"
fi
# Fix up /usr/bin/env shebangs relied on by the build
patchShebangs --build tests/ doc/manual/
'';
mesonBuildType = "debugoptimized";
installTargets = lib.optional internalApiDocs "internal-api-html";
enableParallelBuilding = true;
doCheck = canRunInstalled;
mesonCheckFlags = [
"--suite=check"
"--print-errorlogs"
];
# the tests access localhost.
__darwinAllowLocalNetworking = true;
# Make sure the internal API docs are already built, because mesonInstallPhase
# won't let us build them there. They would normally be built in buildPhase,
# but the internal API docs are conventionally built with doBuild = false.
preInstall = lib.optional internalApiDocs ''
meson ''${mesonBuildFlags:-} compile "$installTargets"
'';
postInstall =
lib.optionalString (!finalAttrs.dontBuild) ''
mkdir -p $doc/nix-support
echo "doc manual $doc/share/doc/nix/manual" >> $doc/nix-support/hydra-build-products
''
+ lib.optionalString hostPlatform.isStatic ''
mkdir -p $out/nix-support
echo "file binary-dist $out/bin/nix" >> $out/nix-support/hydra-build-products
''
+ lib.optionalString stdenv.isDarwin ''
for lib in liblixutil.dylib liblixexpr.dylib; do
install_name_tool \
-change "${lib.getLib boost}/lib/libboost_context.dylib" \
"$out/lib/libboost_context.dylib" \
"$out/lib/$lib"
done
''
+ lib.optionalString internalApiDocs ''
mkdir -p $out/nix-support
echo "doc internal-api-docs $out/share/doc/nix/internal-api/html" >> "$out/nix-support/hydra-build-products"
'';
doInstallCheck = finalAttrs.doCheck;
mesonInstallCheckFlags = [
"--suite=installcheck"
"--print-errorlogs"
];
installCheckPhase = ''
runHook preInstallCheck
flagsArray=($mesonInstallCheckFlags "''${mesonInstallCheckFlagsArray[@]}")
meson test --no-rebuild "''${flagsArray[@]}"
runHook postInstallCheck
'';
separateDebugInfo = !hostPlatform.isStatic && !finalAttrs.dontBuild;
strictDeps = true;
# strictoverflow is disabled because we trap on signed overflow instead
hardeningDisable = [ "strictoverflow" ] ++ lib.optional hostPlatform.isStatic "pie";
meta = {
mainProgram = "nix";
platforms = lib.platforms.unix;
};
# Export the patched version of boehmgc.
# flake.nix exports that into its overlay.
passthru = {
inherit (__forDefaults)
boehmgc-nix
editline-lix
build-release-notes
pegtl
;
inherit officialRelease;
# The collection of dependency logic for this derivation is complicated enough that
# it's easier to parameterize the devShell off an already called package.nix.
mkDevShell =
{
mkShell,
bashInteractive,
clang-tools,
clangbuildanalyzer,
doxygen,
glibcLocales,
just,
llvmPackages,
nixfmt-rfc-style,
skopeo,
xonsh,
# Lix specific packages
pre-commit-checks,
contribNotice,
check-syscalls,
}:
let
glibcFix = lib.optionalAttrs (buildPlatform.isLinux && glibcLocales != null) {
# Required to make non-NixOS Linux not complain about missing locale files during configure in a dev shell
LOCALE_ARCHIVE = "${lib.getLib pkgs.glibcLocales}/lib/locale/locale-archive";
};
pythonPackages = (
p: [
p.yapf
p.python-frontmatter
p.requests
p.xdg-base-dirs
(p.toPythonModule xonsh.passthru.unwrapped)
]
);
pythonEnv = python3.withPackages pythonPackages;
# pkgs.mkShell uses pkgs.stdenv by default, regardless of inputsFrom.
actualMkShell = mkShell.override { inherit stdenv; };
in
actualMkShell (
glibcFix
// {
name = "lix-shell-env";
# finalPackage is necessary to propagate stuff that is set by mkDerivation itself,
# like doCheck.
inputsFrom = [ finalAttrs.finalPackage ];
# For Meson to find Boost.
env = finalAttrs.env;
mesonFlags =
# I guess this is necessary because mesonFlags to mkDerivation doesn't propagate in inputsFrom,
# which only propagates stuff set in hooks? idk.
finalAttrs.mesonFlags
# Clangd breaks when GCC is using precompiled headers, so for the devshell specifically
# we make precompiled C++ stdlib conditional on using Clang.
# https://git.lix.systems/lix-project/lix/issues/374
++ [ (lib.mesonBool "enable-pch-std" stdenv.cc.isClang) ];
packages =
lib.optional (stdenv.cc.isClang && hostPlatform == buildPlatform) clang-tools
++ [
# Why are we providing a bashInteractive? Well, when you run
# `bash` from inside `nix develop`, say, because you are using it
# via direnv, you will by default get bash (unusable edition).
bashInteractive
check-syscalls
pythonEnv
# docker image tool
skopeo
just
nixfmt-rfc-style
# Included above when internalApiDocs is true, but we set that to
# false intentionally to save dev build time.
# To build them in a dev shell, you can set -Dinternal-api-docs=enabled when configuring.
doxygen
# Load-bearing order. Must come before clang-unwrapped below, but after clang_tools above.
stdenv.cc
]
++ [
pkgs.rust-analyzer
pkgs.cargo
pkgs.rustc
pkgs.rustfmt
pkgs.rustPlatform.rustLibSrc
pkgs.rustPlatform.rustcSrc
]
++ lib.optionals stdenv.cc.isClang [
# Required for clang-tidy checks.
llvmPackages.llvm
llvmPackages.clang-unwrapped.dev
]
++ lib.optional (pre-commit-checks ? enabledPackages) pre-commit-checks.enabledPackages
++ lib.optional (lib.meta.availableOn buildPlatform clangbuildanalyzer) clangbuildanalyzer
++ finalAttrs.checkInputs;
shellHook = ''
# don't re-run the hook in (other) nested nix-shells
function lixShellHook() {
# n.b. how the heck does this become -env-env? well, `nix develop` does it:
# https://git.lix.systems/lix-project/lix/src/commit/7575db522e9008685c4009423398f6900a16bcce/src/nix/develop.cc#L240-L241
# this is, of course, absurd.
if [[ $name != lix-shell-env && $name != lix-shell-env-env ]]; then
return
fi
PATH=$prefix/bin''${PATH:+:''${PATH}}
unset PYTHONPATH
export MANPATH=$out/share/man''${MANPATH:+:''${MANPATH}}
# Make bash completion work.
XDG_DATA_DIRS+=:$out/share
if [[ ! -f ./.this-is-lix ]]; then
echo "Dev shell not started from inside a Lix repo, skipping repo setup" >&2
return
fi
${lib.optionalString (pre-commit-checks ? shellHook) pre-commit-checks.shellHook}
# Allow `touch .nocontribmsg` to turn this notice off.
if ! [[ -f .nocontribmsg ]]; then
cat ${contribNotice}
fi
# Install the Gerrit commit-msg hook.
# (git common dir is the main .git, including for worktrees)
if gitcommondir=$(git rev-parse --git-common-dir 2>/dev/null) && [[ ! -f "$gitcommondir/hooks/commit-msg" ]]; then
echo 'Installing Gerrit commit-msg hook (adds Change-Id to commit messages)' >&2
mkdir -p "$gitcommondir/hooks"
curl -s -Lo "$gitcommondir/hooks/commit-msg" https://gerrit.lix.systems/tools/hooks/commit-msg
chmod u+x "$gitcommondir/hooks/commit-msg"
fi
unset gitcommondir
}
lixShellHook
'';
}
);
perl-bindings = pkgs.callPackage ./perl { inherit fileset stdenv; };
binaryTarball = pkgs.callPackage ./nix-support/binary-tarball.nix {
nix = finalAttrs.finalPackage;
};
};
})