1853015550
pam-ussh allows authorizing using an SSH certificate stored in your SSH agent, in a similar manner to pam-ssh-agent-auth, but for certificates rather than raw public keys.
265 lines
8.2 KiB
Nix
265 lines
8.2 KiB
Nix
{ config, lib, pkgs, ... }:
|
||
|
||
with lib;
|
||
|
||
let
|
||
|
||
cfg = config.security.sudo;
|
||
|
||
inherit (pkgs) sudo;
|
||
|
||
toUserString = user: if (isInt user) then "#${toString user}" else "${user}";
|
||
toGroupString = group: if (isInt group) then "%#${toString group}" else "%${group}";
|
||
|
||
toCommandOptionsString = options:
|
||
"${concatStringsSep ":" options}${optionalString (length options != 0) ":"} ";
|
||
|
||
toCommandsString = commands:
|
||
concatStringsSep ", " (
|
||
map (command:
|
||
if (isString command) then
|
||
command
|
||
else
|
||
"${toCommandOptionsString command.options}${command.command}"
|
||
) commands
|
||
);
|
||
|
||
in
|
||
|
||
{
|
||
|
||
###### interface
|
||
|
||
options = {
|
||
|
||
security.sudo.enable = mkOption {
|
||
type = types.bool;
|
||
default = true;
|
||
description =
|
||
''
|
||
Whether to enable the <command>sudo</command> command, which
|
||
allows non-root users to execute commands as root.
|
||
'';
|
||
};
|
||
|
||
security.sudo.package = mkOption {
|
||
type = types.package;
|
||
default = pkgs.sudo;
|
||
defaultText = literalExpression "pkgs.sudo";
|
||
description = ''
|
||
Which package to use for `sudo`.
|
||
'';
|
||
};
|
||
|
||
security.sudo.wheelNeedsPassword = mkOption {
|
||
type = types.bool;
|
||
default = true;
|
||
description =
|
||
''
|
||
Whether users of the <code>wheel</code> group must
|
||
provide a password to run commands as super user via <command>sudo</command>.
|
||
'';
|
||
};
|
||
|
||
security.sudo.execWheelOnly = mkOption {
|
||
type = types.bool;
|
||
default = false;
|
||
description = ''
|
||
Only allow members of the <code>wheel</code> group to execute sudo by
|
||
setting the executable's permissions accordingly.
|
||
This prevents users that are not members of <code>wheel</code> from
|
||
exploiting vulnerabilities in sudo such as CVE-2021-3156.
|
||
'';
|
||
};
|
||
|
||
security.sudo.configFile = mkOption {
|
||
type = types.lines;
|
||
# Note: if syntax errors are detected in this file, the NixOS
|
||
# configuration will fail to build.
|
||
description =
|
||
''
|
||
This string contains the contents of the
|
||
<filename>sudoers</filename> file.
|
||
'';
|
||
};
|
||
|
||
security.sudo.extraRules = mkOption {
|
||
description = ''
|
||
Define specific rules to be in the <filename>sudoers</filename> file.
|
||
More specific rules should come after more general ones in order to
|
||
yield the expected behavior. You can use mkBefore/mkAfter to ensure
|
||
this is the case when configuration options are merged.
|
||
'';
|
||
default = [];
|
||
example = literalExpression ''
|
||
[
|
||
# Allow execution of any command by all users in group sudo,
|
||
# requiring a password.
|
||
{ groups = [ "sudo" ]; commands = [ "ALL" ]; }
|
||
|
||
# Allow execution of "/home/root/secret.sh" by user `backup`, `database`
|
||
# and the group with GID `1006` without a password.
|
||
{ users = [ "backup" "database" ]; groups = [ 1006 ];
|
||
commands = [ { command = "/home/root/secret.sh"; options = [ "SETENV" "NOPASSWD" ]; } ]; }
|
||
|
||
# Allow all users of group `bar` to run two executables as user `foo`
|
||
# with arguments being pre-set.
|
||
{ groups = [ "bar" ]; runAs = "foo";
|
||
commands =
|
||
[ "/home/baz/cmd1.sh hello-sudo"
|
||
{ command = '''/home/baz/cmd2.sh ""'''; options = [ "SETENV" ]; } ]; }
|
||
]
|
||
'';
|
||
type = with types; listOf (submodule {
|
||
options = {
|
||
users = mkOption {
|
||
type = with types; listOf (either str int);
|
||
description = ''
|
||
The usernames / UIDs this rule should apply for.
|
||
'';
|
||
default = [];
|
||
};
|
||
|
||
groups = mkOption {
|
||
type = with types; listOf (either str int);
|
||
description = ''
|
||
The groups / GIDs this rule should apply for.
|
||
'';
|
||
default = [];
|
||
};
|
||
|
||
host = mkOption {
|
||
type = types.str;
|
||
default = "ALL";
|
||
description = ''
|
||
For what host this rule should apply.
|
||
'';
|
||
};
|
||
|
||
runAs = mkOption {
|
||
type = with types; str;
|
||
default = "ALL:ALL";
|
||
description = ''
|
||
Under which user/group the specified command is allowed to run.
|
||
|
||
A user can be specified using just the username: <code>"foo"</code>.
|
||
It is also possible to specify a user/group combination using <code>"foo:bar"</code>
|
||
or to only allow running as a specific group with <code>":bar"</code>.
|
||
'';
|
||
};
|
||
|
||
commands = mkOption {
|
||
description = ''
|
||
The commands for which the rule should apply.
|
||
'';
|
||
type = with types; listOf (either str (submodule {
|
||
|
||
options = {
|
||
command = mkOption {
|
||
type = with types; str;
|
||
description = ''
|
||
A command being either just a path to a binary to allow any arguments,
|
||
the full command with arguments pre-set or with <code>""</code> used as the argument,
|
||
not allowing arguments to the command at all.
|
||
'';
|
||
};
|
||
|
||
options = mkOption {
|
||
type = with types; listOf (enum [ "NOPASSWD" "PASSWD" "NOEXEC" "EXEC" "SETENV" "NOSETENV" "LOG_INPUT" "NOLOG_INPUT" "LOG_OUTPUT" "NOLOG_OUTPUT" ]);
|
||
description = ''
|
||
Options for running the command. Refer to the <a href="https://www.sudo.ws/man/1.7.10/sudoers.man.html">sudo manual</a>.
|
||
'';
|
||
default = [];
|
||
};
|
||
};
|
||
|
||
}));
|
||
};
|
||
};
|
||
});
|
||
};
|
||
|
||
security.sudo.extraConfig = mkOption {
|
||
type = types.lines;
|
||
default = "";
|
||
description = ''
|
||
Extra configuration text appended to <filename>sudoers</filename>.
|
||
'';
|
||
};
|
||
};
|
||
|
||
|
||
###### implementation
|
||
|
||
config = mkIf cfg.enable {
|
||
|
||
# We `mkOrder 600` so that the default rule shows up first, but there is
|
||
# still enough room for a user to `mkBefore` it.
|
||
security.sudo.extraRules = mkOrder 600 [
|
||
{ groups = [ "wheel" ];
|
||
commands = [ { command = "ALL"; options = (if cfg.wheelNeedsPassword then [ "SETENV" ] else [ "NOPASSWD" "SETENV" ]); } ];
|
||
}
|
||
];
|
||
|
||
security.sudo.configFile =
|
||
''
|
||
# Don't edit this file. Set the NixOS options ‘security.sudo.configFile’
|
||
# or ‘security.sudo.extraRules’ instead.
|
||
|
||
# Keep SSH_AUTH_SOCK so that pam_ssh_agent_auth.so can do its magic.
|
||
Defaults env_keep+=SSH_AUTH_SOCK
|
||
|
||
# "root" is allowed to do anything.
|
||
root ALL=(ALL:ALL) SETENV: ALL
|
||
|
||
# extraRules
|
||
${concatStringsSep "\n" (
|
||
lists.flatten (
|
||
map (
|
||
rule: if (length rule.commands != 0) then [
|
||
(map (user: "${toUserString user} ${rule.host}=(${rule.runAs}) ${toCommandsString rule.commands}") rule.users)
|
||
(map (group: "${toGroupString group} ${rule.host}=(${rule.runAs}) ${toCommandsString rule.commands}") rule.groups)
|
||
] else []
|
||
) cfg.extraRules
|
||
)
|
||
)}
|
||
|
||
${cfg.extraConfig}
|
||
'';
|
||
|
||
security.wrappers = let
|
||
owner = "root";
|
||
group = if cfg.execWheelOnly then "wheel" else "root";
|
||
setuid = true;
|
||
permissions = if cfg.execWheelOnly then "u+rx,g+x" else "u+rx,g+x,o+x";
|
||
in {
|
||
sudo = {
|
||
source = "${cfg.package.out}/bin/sudo";
|
||
inherit owner group setuid permissions;
|
||
};
|
||
sudoedit = {
|
||
source = "${cfg.package.out}/bin/sudoedit";
|
||
inherit owner group setuid permissions;
|
||
};
|
||
};
|
||
|
||
environment.systemPackages = [ sudo ];
|
||
|
||
security.pam.services.sudo = { sshAgentAuth = true; usshAuth = true; };
|
||
|
||
environment.etc.sudoers =
|
||
{ source =
|
||
pkgs.runCommand "sudoers"
|
||
{
|
||
src = pkgs.writeText "sudoers-in" cfg.configFile;
|
||
preferLocalBuild = true;
|
||
}
|
||
# Make sure that the sudoers file is syntactically valid.
|
||
# (currently disabled - NIXOS-66)
|
||
"${pkgs.buildPackages.sudo}/sbin/visudo -f $src -c && cp $src $out";
|
||
mode = "0440";
|
||
};
|
||
|
||
};
|
||
|
||
}
|