Merge pull request #60187 from joachifm/feat/configurable-malloc

nixos: configurable system-wide malloc
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Joachim F 2019-05-12 15:18:07 +00:00 committed by GitHub
commit b4a43a278b
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4 changed files with 121 additions and 0 deletions

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@ -0,0 +1,91 @@
{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.environment.memoryAllocator;
# The set of alternative malloc(3) providers.
providers = {
"graphene-hardened" = rec {
libPath = "${pkgs.graphene-hardened-malloc}/lib/libhardened_malloc.so";
description = ''
An allocator designed to mitigate memory corruption attacks, such as
those caused by use-after-free bugs.
'';
};
"jemalloc" = {
libPath = "${pkgs.jemalloc}/lib/libjemalloc.so";
description = ''
A general purpose allocator that emphasizes fragmentation avoidance
and scalable concurrency support.
'';
};
};
providerConf = providers."${cfg.provider}";
# An output that contains only the shared library, to avoid
# needlessly bloating the system closure
mallocLib = pkgs.runCommand "malloc-provider-${cfg.provider}"
rec {
preferLocalBuild = true;
allowSubstitutes = false;
origLibPath = providerConf.libPath;
libName = baseNameOf origLibPath;
}
''
mkdir -p $out/lib
cp -L $origLibPath $out/lib/$libName
'';
# The full path to the selected provider shlib.
providerLibPath = "${mallocLib}/lib/${mallocLib.libName}";
in
{
meta = {
maintainers = [ maintainers.joachifm ];
};
options = {
environment.memoryAllocator.provider = mkOption {
type = types.enum ([ "libc" ] ++ attrNames providers);
default = "libc";
description = ''
The system-wide memory allocator.
</para>
<para>
Briefly, the system-wide memory allocator providers are:
<itemizedlist>
<listitem><para><literal>libc</literal>: the standard allocator provided by libc</para></listitem>
${toString (mapAttrsToList
(name: value: "<listitem><para><literal>${name}</literal>: ${value.description}</para></listitem>")
providers)}
</itemizedlist>
</para>
<warning>
<para>
Selecting an alternative allocator (i.e., anything other than
<literal>libc</literal>) may result in instability, data loss,
and/or service failure.
</para>
</warning>
<note>
<para>
Changing this option does not affect the current session.
</para>
</note>
<para>
'';
};
};
config = mkIf (cfg.provider != "libc") {
environment.variables.LD_PRELOAD = providerLibPath;
};
}

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@ -19,6 +19,7 @@
./config/iproute2.nix
./config/krb5/default.nix
./config/ldap.nix
./config/malloc.nix
./config/networking.nix
./config/no-x-libs.nix
./config/nsswitch.nix

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@ -14,6 +14,8 @@ with lib;
nix.allowedUsers = mkDefault [ "@users" ];
environment.memoryAllocator.provider = mkDefault "graphene-hardened";
security.hideProcessInformation = mkDefault true;
security.lockKernelModules = mkDefault true;

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@ -27,6 +27,20 @@ import ./make-test.nix ({ pkgs, ...} : {
};
testScript =
let
hardened-malloc-tests = pkgs.stdenv.mkDerivation rec {
name = "hardened-malloc-tests-${pkgs.graphene-hardened-malloc.version}";
src = pkgs.graphene-hardened-malloc.src;
buildPhase = ''
cd test/simple-memory-corruption
make -j4
'';
installPhase = ''
find . -type f -executable -exec install -Dt $out/bin '{}' +
'';
};
in
''
$machine->waitForUnit("multi-user.target");
@ -93,5 +107,18 @@ import ./make-test.nix ({ pkgs, ...} : {
$machine->fail("systemctl hibernate");
$machine->fail("systemctl kexec");
};
# Test hardened memory allocator
sub runMallocTestProg {
my ($progName, $errorText) = @_;
my $text = "fatal allocator error: " . $errorText;
$machine->fail("${hardened-malloc-tests}/bin/" . $progName) =~ $text;
};
subtest "hardenedmalloc", sub {
runMallocTestProg("double_free_large", "invalid free");
runMallocTestProg("unaligned_free_small", "invalid unaligned free");
runMallocTestProg("write_after_free_small", "detected write after free");
};
'';
})