 cef2814a4f
			
		
	
	
		cef2814a4f
		
	
	
	
	
		
			
			This module adds an option `security.hideProcessInformation` that, when enabled, restricts access to process information such as command-line arguments to the process owner. The module adds a static group "proc" whose members are exempt from process information hiding. Ideally, this feature would be implemented by simply adding the appropriate mount options to `fileSystems."/proc".fsOptions`, but this was found to not work in vmtests. To ensure that process information hiding is enforced, we use a systemd service unit that remounts `/proc` after `systemd-remount-fs.service` has completed. To verify the correctness of the feature, simple tests were added to nixos/tests/misc: the test ensures that unprivileged users cannot see process information owned by another user, while members of "proc" CAN. Thanks to @abbradar for feedback and suggestions.
		
			
				
	
	
		
			131 lines
		
	
	
		
			4.4 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
			
		
		
	
	
			131 lines
		
	
	
		
			4.4 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
| # Miscellaneous small tests that don't warrant their own VM run.
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| 
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| import ./make-test.nix ({ pkgs, ...} : {
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|   name = "misc";
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|   meta = with pkgs.stdenv.lib.maintainers; {
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|     maintainers = [ eelco chaoflow ];
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|   };
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| 
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|   machine =
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|     { config, lib, pkgs, ... }:
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|     with lib;
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|     { swapDevices = mkOverride 0
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|         [ { device = "/root/swapfile"; size = 128; } ];
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|       environment.variables.EDITOR = mkOverride 0 "emacs";
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|       services.nixosManual.enable = mkOverride 0 true;
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|       systemd.tmpfiles.rules = [ "d /tmp 1777 root root 10d" ];
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|       fileSystems = mkVMOverride { "/tmp2" =
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|         { fsType = "tmpfs";
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|           options = [ "mode=1777" "noauto" ];
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|         };
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|       };
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|       systemd.automounts = singleton
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|         { wantedBy = [ "multi-user.target" ];
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|           where = "/tmp2";
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|         };
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|       users.users.sybil = { isNormalUser = true; group = "wheel"; };
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|       security.sudo = { enable = true; wheelNeedsPassword = false; };
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|       security.hideProcessInformation = true;
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|       users.users.alice = { isNormalUser = true; extraGroups = [ "proc" ]; };
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|     };
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| 
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|   testScript =
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|     ''
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|       subtest "nixos-version", sub {
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|           $machine->succeed("[ `nixos-version | wc -w` = 2 ]");
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|       };
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| 
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|       subtest "nixos-rebuild", sub {
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|           $machine->succeed("nixos-rebuild --help | grep SYNOPSIS");
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|       };
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| 
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|       # Sanity check for uid/gid assignment.
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|       subtest "users-groups", sub {
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|           $machine->succeed("[ `id -u messagebus` = 4 ]");
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|           $machine->succeed("[ `id -g messagebus` = 4 ]");
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|           $machine->succeed("[ `getent group users` = 'users:x:100:' ]");
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|       };
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| 
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|       # Regression test for GMP aborts on QEMU.
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|       subtest "gmp", sub {
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|           $machine->succeed("expr 1 + 2");
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|       };
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| 
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|       # Test that the swap file got created.
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|       subtest "swapfile", sub {
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|           $machine->waitForUnit("root-swapfile.swap");
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|           $machine->succeed("ls -l /root/swapfile | grep 134217728");
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|       };
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| 
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|       # Test whether kernel.poweroff_cmd is set.
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|       subtest "poweroff_cmd", sub {
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|           $machine->succeed("[ -x \"\$(cat /proc/sys/kernel/poweroff_cmd)\" ]")
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|       };
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| 
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|       # Test whether the blkio controller is properly enabled.
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|       subtest "blkio-cgroup", sub {
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|           $machine->succeed("[ -n \"\$(cat /sys/fs/cgroup/blkio/blkio.sectors)\" ]")
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|       };
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| 
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|       # Test whether we have a reboot record in wtmp.
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|       subtest "reboot-wtmp", sub {
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|           $machine->succeed("last | grep reboot >&2");
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|       };
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| 
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|       # Test whether we can override environment variables.
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|       subtest "override-env-var", sub {
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|           $machine->succeed('[ "$EDITOR" = emacs ]');
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|       };
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| 
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|       # Test whether hostname (and by extension nss_myhostname) works.
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|       subtest "hostname", sub {
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|           $machine->succeed('[ "`hostname`" = machine ]');
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|           #$machine->succeed('[ "`hostname -s`" = machine ]');
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|       };
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| 
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|       # Test whether systemd-udevd automatically loads modules for our hardware.
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|       $machine->succeed("systemctl start systemd-udev-settle.service");
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|       subtest "udev-auto-load", sub {
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|           $machine->waitForUnit('systemd-udev-settle.service');
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|           $machine->succeed('lsmod | grep psmouse');
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|       };
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| 
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|       # Test whether systemd-tmpfiles-clean works.
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|       subtest "tmpfiles", sub {
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|           $machine->succeed('touch /tmp/foo');
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|           $machine->succeed('systemctl start systemd-tmpfiles-clean');
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|           $machine->succeed('[ -e /tmp/foo ]');
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|           $machine->succeed('date -s "@$(($(date +%s) + 1000000))"'); # move into the future
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|           $machine->succeed('systemctl start systemd-tmpfiles-clean');
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|           $machine->fail('[ -e /tmp/foo ]');
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|       };
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| 
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|       # Test whether automounting works.
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|       subtest "automount", sub {
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|           $machine->fail("grep '/tmp2 tmpfs' /proc/mounts");
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|           $machine->succeed("touch /tmp2/x");
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|           $machine->succeed("grep '/tmp2 tmpfs' /proc/mounts");
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|       };
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| 
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|       subtest "shell-vars", sub {
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|           $machine->succeed('[ -n "$NIX_PATH" ]');
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|       };
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| 
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|       subtest "nix-db", sub {
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|           $machine->succeed("nix-store -qR /run/current-system | grep nixos-");
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|       };
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| 
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|       # Test sudo
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|       subtest "sudo", sub {
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|           $machine->succeed("su - sybil -c 'sudo true'");
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|       };
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| 
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|       # Test hidepid
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|       subtest "hidepid", sub {
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|           $machine->succeed("grep -Fq hidepid=2 /etc/mtab");
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|           $machine->succeed("[ `su - sybil -c 'pgrep -c -u root'` = 0 ]");
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|           $machine->succeed("[ `su - alice -c 'pgrep -c -u root'` != 0 ]");
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|       };
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|     '';
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| })
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