import ./make-test-python.nix ({ pkgs, ... }: let userUid = 1000; usersGid = 100; busybox = pkgs : pkgs.busybox.override { # Without this, the busybox binary drops euid to ruid for most applets, including id. # See https://bugs.busybox.net/show_bug.cgi?id=15101 extraConfig = "CONFIG_FEATURE_SUID n"; }; in { name = "wrappers"; nodes.machine = { config, pkgs, ... }: { ids.gids.users = usersGid; users.users = { regular = { uid = userUid; isNormalUser = true; }; }; security.wrappers = { suidRoot = { owner = "root"; group = "root"; setuid = true; source = "${busybox pkgs}/bin/busybox"; program = "suid_root_busybox"; }; sgidRoot = { owner = "root"; group = "root"; setgid = true; source = "${busybox pkgs}/bin/busybox"; program = "sgid_root_busybox"; }; withChown = { owner = "root"; group = "root"; source = "${pkgs.libcap}/bin/capsh"; program = "capsh_with_chown"; capabilities = "cap_chown+ep"; }; }; }; testScript = '' def cmd_as_regular(cmd): return "su -l regular -c '{0}'".format(cmd) def test_as_regular(cmd, expected): out = machine.succeed(cmd_as_regular(cmd)).strip() assert out == expected, "Expected {0} to output {1}, but got {2}".format(cmd, expected, out) def test_as_regular_in_userns_mapped_as_root(cmd, expected): out = machine.succeed(f"su -l regular -c '${pkgs.util-linux}/bin/unshare -rm {cmd}'").strip() assert out == expected, "Expected {0} to output {1}, but got {2}".format(cmd, expected, out) test_as_regular('${busybox pkgs}/bin/busybox id -u', '${toString userUid}') test_as_regular('${busybox pkgs}/bin/busybox id -ru', '${toString userUid}') test_as_regular('${busybox pkgs}/bin/busybox id -g', '${toString usersGid}') test_as_regular('${busybox pkgs}/bin/busybox id -rg', '${toString usersGid}') test_as_regular('/run/wrappers/bin/suid_root_busybox id -u', '0') test_as_regular('/run/wrappers/bin/suid_root_busybox id -ru', '${toString userUid}') test_as_regular('/run/wrappers/bin/suid_root_busybox id -g', '${toString usersGid}') test_as_regular('/run/wrappers/bin/suid_root_busybox id -rg', '${toString usersGid}') test_as_regular('/run/wrappers/bin/sgid_root_busybox id -u', '${toString userUid}') test_as_regular('/run/wrappers/bin/sgid_root_busybox id -ru', '${toString userUid}') test_as_regular('/run/wrappers/bin/sgid_root_busybox id -g', '0') test_as_regular('/run/wrappers/bin/sgid_root_busybox id -rg', '${toString usersGid}') test_as_regular_in_userns_mapped_as_root('/run/wrappers/bin/suid_root_busybox id -u', '0') test_as_regular_in_userns_mapped_as_root('/run/wrappers/bin/suid_root_busybox id -ru', '0') test_as_regular_in_userns_mapped_as_root('/run/wrappers/bin/suid_root_busybox id -g', '0') test_as_regular_in_userns_mapped_as_root('/run/wrappers/bin/suid_root_busybox id -rg', '0') test_as_regular_in_userns_mapped_as_root('/run/wrappers/bin/sgid_root_busybox id -u', '0') test_as_regular_in_userns_mapped_as_root('/run/wrappers/bin/sgid_root_busybox id -ru', '0') test_as_regular_in_userns_mapped_as_root('/run/wrappers/bin/sgid_root_busybox id -g', '0') test_as_regular_in_userns_mapped_as_root('/run/wrappers/bin/sgid_root_busybox id -rg', '0') # We are only testing the permitted set, because it's easiest to look at with capsh. machine.fail(cmd_as_regular('${pkgs.libcap}/bin/capsh --has-p=CAP_CHOWN')) machine.fail(cmd_as_regular('${pkgs.libcap}/bin/capsh --has-p=CAP_SYS_ADMIN')) machine.succeed(cmd_as_regular('/run/wrappers/bin/capsh_with_chown --has-p=CAP_CHOWN')) machine.fail(cmd_as_regular('/run/wrappers/bin/capsh_with_chown --has-p=CAP_SYS_ADMIN')) # test a few "attacks" against which the wrapper protects itself machine.succeed("cp /run/wrappers/bin/suid_root_busybox{,.real} /tmp/") machine.fail(cmd_as_regular("/tmp/suid_root_busybox id -u")) machine.succeed("chmod u+s,a+w /run/wrappers/bin/suid_root_busybox") machine.fail(cmd_as_regular("/run/wrappers/bin/suid_root_busybox id -u")) ''; })