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|
{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.environment.memoryAllocator;
# The set of alternative malloc(3) providers.
providers = {
graphene-hardened = {
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.
'';
};
scudo = {
libPath = "${pkgs.llvmPackages_latest.compiler-rt}/lib/linux/libclang_rt.scudo-x86_64.so";
description = ''
A user-mode allocator based on LLVM Sanitizer’s CombinedAllocator,
which aims at providing additional mitigations against heap based
vulnerabilities, while maintaining good performance.
'';
};
};
providerConf = providers.${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.
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>
<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>
'';
};
};
config = mkIf (cfg.provider != "libc") {
environment.etc."ld-nix.so.preload".text = ''
${providerLibPath}
'';
security.apparmor.includes = {
"abstractions/base" = ''
r /etc/ld-nix.so.preload,
r ${config.environment.etc."ld-nix.so.preload".source},
mr ${providerLibPath},
'';
};
};
}
|