Merge pull request #106082 from rnhmjoj/uwsgi

nixos/uwsgi: run with capabilities instead of root
This commit is contained in:
Guillaume Girol 2021-01-10 21:51:37 +00:00 committed by GitHub
commit 0fbc0976db
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5 changed files with 135 additions and 34 deletions

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@ -185,6 +185,30 @@
with <literal>mkfs.xfs -m reflink=0</literal>.
</para>
</listitem>
<listitem>
<para>
The uWSGI server is now built with POSIX capabilities. As a consequence,
root is no longer required in emperor mode and the service defaults to
running as the unprivileged <literal>uwsgi</literal> user. Any additional
capability can be added via the new option
<xref linkend="opt-services.uwsgi.capabilities"/>.
The previous behaviour can be restored by setting:
<programlisting>
<xref linkend="opt-services.uwsgi.user"/> = "root";
<xref linkend="opt-services.uwsgi.group"/> = "root";
<xref linkend="opt-services.uwsgi.instance"/> =
{
uid = "uwsgi";
gid = "uwsgi";
};
</programlisting>
</para>
<para>
Another incompatibility from the previous release is that vassals running under a
different user or group need to use <literal>immediate-{uid,gid}</literal>
instead of the usual <literal>uid,gid</literal> options.
</para>
</listitem>
<listitem>
<para>
<package>btc1</package> has been abandoned upstream, and removed.

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@ -44,7 +44,7 @@ let
in
{
options.services.ihatemoney = {
enable = mkEnableOption "ihatemoney webapp. Note that this will set uwsgi to emperor mode running as root";
enable = mkEnableOption "ihatemoney webapp. Note that this will set uwsgi to emperor mode";
backend = mkOption {
type = types.enum [ "sqlite" "postgresql" ];
default = "sqlite";
@ -116,16 +116,13 @@ in
services.uwsgi = {
enable = true;
plugins = [ "python3" ];
# the vassal needs to be able to setuid
user = "root";
group = "root";
instance = {
type = "emperor";
vassals.ihatemoney = {
type = "normal";
strict = true;
uid = user;
gid = group;
immediate-uid = user;
immediate-gid = group;
# apparently flask uses threads: https://github.com/spiral-project/ihatemoney/commit/c7815e48781b6d3a457eaff1808d179402558f8c
enable-threads = true;
module = "wsgi:application";

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@ -5,11 +5,24 @@ with lib;
let
cfg = config.services.uwsgi;
isEmperor = cfg.instance.type == "emperor";
imperialPowers =
[
# spawn other user processes
"CAP_SETUID" "CAP_SETGID"
"CAP_SYS_CHROOT"
# transfer capabilities
"CAP_SETPCAP"
# create other user sockets
"CAP_CHOWN"
];
buildCfg = name: c:
let
plugins =
if any (n: !any (m: m == n) cfg.plugins) (c.plugins or [])
then throw "`plugins` attribute in UWSGI configuration contains plugins not in config.services.uwsgi.plugins"
then throw "`plugins` attribute in uWSGI configuration contains plugins not in config.services.uwsgi.plugins"
else c.plugins or cfg.plugins;
hasPython = v: filter (n: n == "python${v}") plugins != [];
@ -18,7 +31,7 @@ let
python =
if hasPython2 && hasPython3 then
throw "`plugins` attribute in UWSGI configuration shouldn't contain both python2 and python3"
throw "`plugins` attribute in uWSGI configuration shouldn't contain both python2 and python3"
else if hasPython2 then cfg.package.python2
else if hasPython3 then cfg.package.python3
else null;
@ -43,7 +56,7 @@ let
oldPaths = filter (x: x != null) (map getPath env');
in env' ++ [ "PATH=${optionalString (oldPaths != []) "${last oldPaths}:"}${pythonEnv}/bin" ];
}
else if c.type == "emperor"
else if isEmperor
then {
emperor = if builtins.typeOf c.vassals != "set" then c.vassals
else pkgs.buildEnv {
@ -51,7 +64,7 @@ let
paths = mapAttrsToList buildCfg c.vassals;
};
} // removeAttrs c [ "type" "vassals" ]
else throw "`type` attribute in UWSGI configuration should be either 'normal' or 'emperor'";
else throw "`type` attribute in uWSGI configuration should be either 'normal' or 'emperor'";
};
in pkgs.writeTextDir "${name}.json" (builtins.toJSON uwsgiCfg);
@ -79,7 +92,7 @@ in {
};
instance = mkOption {
type = with lib.types; let
type = with types; let
valueType = nullOr (oneOf [
bool
int
@ -137,31 +150,65 @@ in {
user = mkOption {
type = types.str;
default = "uwsgi";
description = "User account under which uwsgi runs.";
description = "User account under which uWSGI runs.";
};
group = mkOption {
type = types.str;
default = "uwsgi";
description = "Group account under which uwsgi runs.";
description = "Group account under which uWSGI runs.";
};
capabilities = mkOption {
type = types.listOf types.str;
apply = caps: caps ++ optionals isEmperor imperialPowers;
default = [ ];
example = literalExample ''
[
"CAP_NET_BIND_SERVICE" # bind on ports <1024
"CAP_NET_RAW" # open raw sockets
]
'';
description = ''
Grant capabilities to the uWSGI instance. See the
<literal>capabilities(7)</literal> for available values.
<note>
<para>
uWSGI runs as an unprivileged user (even as Emperor) with the minimal
capabilities required. This option can be used to add fine-grained
permissions without running the service as root.
</para>
<para>
When in Emperor mode, any capability to be inherited by a vassal must
be specified again in the vassal configuration using <literal>cap</literal>.
See the uWSGI <link
xlink:href="https://uwsgi-docs.readthedocs.io/en/latest/Capabilities.html">docs</link>
for more information.
</para>
</note>
'';
};
};
};
config = mkIf cfg.enable {
systemd.tmpfiles.rules = optional (cfg.runDir != "/run/uwsgi") ''
d ${cfg.runDir} 775 ${cfg.user} ${cfg.group}
'';
systemd.services.uwsgi = {
wantedBy = [ "multi-user.target" ];
preStart = ''
mkdir -p ${cfg.runDir}
chown ${cfg.user}:${cfg.group} ${cfg.runDir}
'';
serviceConfig = {
User = cfg.user;
Group = cfg.group;
Type = "notify";
ExecStart = "${cfg.package}/bin/uwsgi --uid ${cfg.user} --gid ${cfg.group} --json ${buildCfg "server" cfg.instance}/server.json";
ExecStart = "${cfg.package}/bin/uwsgi --json ${buildCfg "server" cfg.instance}/server.json";
ExecReload = "${pkgs.coreutils}/bin/kill -HUP $MAINPID";
ExecStop = "${pkgs.coreutils}/bin/kill -INT $MAINPID";
NotifyAccess = "main";
KillSignal = "SIGQUIT";
AmbientCapabilities = cfg.capabilities;
CapabilityBoundingSet = cfg.capabilities;
};
};

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@ -6,31 +6,48 @@ import ./make-test-python.nix ({ pkgs, ... }:
};
machine = { pkgs, ... }: {
services.uwsgi.enable = true;
services.uwsgi.plugins = [ "python3" "php" ];
services.uwsgi.instance = {
type = "emperor";
vassals.python = {
users.users.hello =
{ isSystemUser = true;
group = "hello";
};
users.groups.hello = { };
services.uwsgi = {
enable = true;
plugins = [ "python3" "php" ];
capabilities = [ "CAP_NET_BIND_SERVICE" ];
instance.type = "emperor";
instance.vassals.hello = {
type = "normal";
master = true;
workers = 2;
http = ":8000";
immediate-uid = "hello";
immediate-gid = "hello";
module = "wsgi:application";
http = ":80";
cap = "net_bind_service";
pythonPackages = self: [ self.flask ];
chdir = pkgs.writeTextDir "wsgi.py" ''
from flask import Flask
import subprocess
application = Flask(__name__)
@application.route("/")
def hello():
return "Hello World!"
return "Hello, World!"
@application.route("/whoami")
def whoami():
whoami = "${pkgs.coreutils}/bin/whoami"
proc = subprocess.run(whoami, capture_output=True)
return proc.stdout.decode().strip()
'';
pythonPackages = self: with self; [ flask ];
};
vassals.php = {
instance.vassals.php = {
type = "normal";
master = true;
workers = 2;
http-socket = ":8001";
http-socket = ":8000";
http-socket-modifier1 = 14;
php-index = "index.php";
php-docroot = pkgs.writeTextDir "index.php" ''
@ -44,9 +61,21 @@ import ./make-test-python.nix ({ pkgs, ... }:
''
machine.wait_for_unit("multi-user.target")
machine.wait_for_unit("uwsgi.service")
machine.wait_for_open_port(8000)
machine.wait_for_open_port(8001)
assert "Hello World" in machine.succeed("curl -fv 127.0.0.1:8000")
assert "Hello World" in machine.succeed("curl -fv 127.0.0.1:8001")
with subtest("uWSGI has started"):
machine.wait_for_unit("uwsgi.service")
with subtest("Vassal can bind on port <1024"):
machine.wait_for_open_port(80)
hello = machine.succeed("curl -f http://machine").strip()
assert "Hello, World!" in hello, f"Excepted 'Hello, World!', got '{hello}'"
with subtest("Vassal is running as dedicated user"):
username = machine.succeed("curl -f http://machine/whoami").strip()
assert username == "hello", f"Excepted 'hello', got '{username}'"
with subtest("PHP plugin is working"):
machine.wait_for_open_port(8000)
assert "Hello World" in machine.succeed("curl -fv http://machine:8000")
'';
})

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@ -3,6 +3,7 @@
, plugins ? []
, pam, withPAM ? stdenv.isLinux
, systemd, withSystemd ? stdenv.isLinux
, libcap, withCap ? stdenv.isLinux
, python2, python3, ncurses
, ruby, php, libmysqlclient
}:
@ -75,6 +76,7 @@ stdenv.mkDerivation rec {
buildInputs = [ jansson pcre ]
++ lib.optional withPAM pam
++ lib.optional withSystemd systemd
++ lib.optional withCap libcap
++ lib.concatMap (x: x.inputs) needed
;
@ -83,6 +85,8 @@ stdenv.mkDerivation rec {
++ lib.optional withSystemd "systemd_logger"
);
UWSGI_INCLUDES = lib.optionalString withCap "${libcap.dev}/include";
passthru = {
inherit python2 python3;
};