92 lines
		
	
	
		
			2.6 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
			
		
		
	
	
			92 lines
		
	
	
		
			2.6 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
| { config, lib, pkgs, ... }:
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| with lib;
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| 
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| let
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|   cfg = config.environment.memoryAllocator;
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| 
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|   # The set of alternative malloc(3) providers.
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|   providers = {
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|     graphene-hardened = {
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|       libPath = "${pkgs.graphene-hardened-malloc}/lib/libhardened_malloc.so";
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|       description = ''
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|         An allocator designed to mitigate memory corruption attacks, such as
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|         those caused by use-after-free bugs.
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|       '';
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|     };
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| 
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|     jemalloc = {
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|       libPath = "${pkgs.jemalloc}/lib/libjemalloc.so";
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|       description = ''
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|         A general purpose allocator that emphasizes fragmentation avoidance
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|         and scalable concurrency support.
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|       '';
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|     };
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| 
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|     scudo = {
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|       libPath = "${pkgs.llvmPackages_latest.compiler-rt}/lib/linux/libclang_rt.scudo-x86_64.so";
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|       description = ''
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|         A user-mode allocator based on LLVM Sanitizer’s CombinedAllocator,
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|         which aims at providing additional mitigations against heap based
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|         vulnerabilities, while maintaining good performance.
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|       '';
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|     };
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|   };
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| 
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|   providerConf = providers.${cfg.provider};
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| 
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|   # An output that contains only the shared library, to avoid
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|   # needlessly bloating the system closure
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|   mallocLib = pkgs.runCommand "malloc-provider-${cfg.provider}"
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|     rec {
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|       preferLocalBuild = true;
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|       allowSubstitutes = false;
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|       origLibPath = providerConf.libPath;
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|       libName = baseNameOf origLibPath;
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|     }
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|     ''
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|       mkdir -p $out/lib
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|       cp -L $origLibPath $out/lib/$libName
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|     '';
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| 
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|   # The full path to the selected provider shlib.
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|   providerLibPath = "${mallocLib}/lib/${mallocLib.libName}";
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| in
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| 
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| {
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|   meta = {
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|     maintainers = [ maintainers.joachifm ];
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|   };
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| 
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|   options = {
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|     environment.memoryAllocator.provider = mkOption {
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|       type = types.enum ([ "libc" ] ++ attrNames providers);
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|       default = "libc";
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|       description = ''
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|         The system-wide memory allocator.
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| 
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|         Briefly, the system-wide memory allocator providers are:
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|         <itemizedlist>
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|         <listitem><para><literal>libc</literal>: the standard allocator provided by libc</para></listitem>
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|         ${toString (mapAttrsToList
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|             (name: value: "<listitem><para><literal>${name}</literal>: ${value.description}</para></listitem>")
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|             providers)}
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|         </itemizedlist>
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| 
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|         <warning>
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|         <para>
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|         Selecting an alternative allocator (i.e., anything other than
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|         <literal>libc</literal>) may result in instability, data loss,
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|         and/or service failure.
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|         </para>
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|         </warning>
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|       '';
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|     };
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|   };
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| 
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|   config = mkIf (cfg.provider != "libc") {
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|     environment.etc."ld-nix.so.preload".text = ''
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|       ${providerLibPath}
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|     '';
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|   };
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| }
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