gnome3.mutter: drop inheritable cap_sys_nice

In NixOS extra capabilities are provided through the ambient set which provides
real inheritability to user run processes [0].

We don't want gome-shell to spawn processes with cap_sys_nice however (apart
from the obvious this also breaks eg. flatpaks). So we drop inheritable when
starting to prevent further inheritance (the ambient set is only propagated
if inherit is set).

[0] 58319057b7
This commit is contained in:
Tor Hedin Brønner 2019-10-19 15:15:20 +02:00
parent c8036d1050
commit 9742df1595
2 changed files with 137 additions and 0 deletions

View file

@ -9,6 +9,7 @@
, wrapGAppsHook
, sysprof
, desktop-file-utils
, libcap_ng
}:
stdenv.mkDerivation rec {
@ -31,6 +32,7 @@ stdenv.mkDerivation rec {
# required for pkgconfig to detect mutter-clutter
libXtst
json-glib
libcap_ng
];
nativeBuildInputs = [
@ -55,6 +57,9 @@ stdenv.mkDerivation rec {
];
patches = [
# Drop inheritable cap_sys_nice, to prevent the ambient set from leaking
# from mutter/gnome-shell, see https://github.com/NixOS/nixpkgs/issues/71381
./drop-inheritable.patch
# TODO: submit upstream
./0001-build-use-get_pkgconfig_variable-for-sysprof-dbusdir.patch
(substituteAll {

View file

@ -0,0 +1,132 @@
From e9c772e265b2293af031c79f4bbc99b5847dfe3c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tor=20Hedin=20Br=C3=B8nner?= <torhedinbronner@gmail.com>
Date: Sat, 19 Oct 2019 13:26:05 +0200
Subject: [PATCH] drop inheritable
Adapted from https://gitlab.gnome.org/GNOME/mutter/commit/c53c47ae123b03cc66044d2b846342123ecb3a01
We only want to drop inheritable though, to prevent the ambient set leaking further than gnome-shell.
---
config.h.meson | 3 +++
meson.build | 5 +++++
meson_options.txt | 6 ++++++
src/core/main.c | 11 +++++++++++
src/meson.build | 1 +
5 files changed, 26 insertions(+)
diff --git a/config.h.meson b/config.h.meson
index 0bab71848..202fb7ed1 100644
--- a/config.h.meson
+++ b/config.h.meson
@@ -58,6 +58,9 @@
/* Xwayland applications allowed to issue keyboard grabs */
#mesondefine XWAYLAND_GRAB_DEFAULT_ACCESS_RULES
+/* Defined if libcap-ng is available */
+#mesondefine HAVE_LIBCAPNG
+
/* XKB base prefix */
#mesondefine XKB_BASE
diff --git a/meson.build b/meson.build
index 3322bd3b1..01c8020fa 100644
--- a/meson.build
+++ b/meson.build
@@ -35,6 +35,7 @@ libstartup_notification_req = '>= 0.7'
libcanberra_req = '>= 0.26'
libwacom_req = '>= 0.13'
atk_req = '>= 2.5.3'
+libcapng_req = '>= 0.7.9'
# optional version requirements
udev_req = '>= 228'
@@ -125,6 +126,7 @@ xau_dep = dependency('xau')
ice_dep = dependency('ice')
atk_dep = dependency('atk', version: atk_req)
libcanberra_dep = dependency('libcanberra', version: libcanberra_req)
+libcapng_dep = dependency('libcap-ng', required: get_option('libcapng'))
# For now always require X11 support
have_x11 = true
@@ -256,6 +258,7 @@ have_core_tests = false
have_cogl_tests = false
have_clutter_tests = false
have_installed_tests = false
+have_libcapng = libcapng_dep.found()
if have_tests
have_core_tests = get_option('core_tests')
@@ -361,6 +364,7 @@ cdata.set('HAVE_LIBWACOM', have_libwacom)
cdata.set('HAVE_SM', have_sm)
cdata.set('HAVE_STARTUP_NOTIFICATION', have_startup_notification)
cdata.set('HAVE_INTROSPECTION', have_introspection)
+cdata.set('HAVE_LIBCAPNG', have_libcapng)
cdata.set('HAVE_PROFILER', have_profiler)
xkb_base = xkeyboard_config_dep.get_pkgconfig_variable('xkb_base')
@@ -443,6 +447,7 @@ output = [
' Startup notification..... ' + have_startup_notification.to_string(),
' Introspection............ ' + have_introspection.to_string(),
' Profiler................. ' + have_profiler.to_string(),
+ ' libcap-ng................ ' + have_libcapng.to_string(),
'',
' Tests:',
'',
diff --git a/meson_options.txt b/meson_options.txt
index 73aa7adde..8bfaacd9a 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -152,3 +152,9 @@ option('xwayland_grab_default_access_rules',
value: 'gnome-boxes,remote-viewer,virt-viewer,virt-manager,vinagre,vncviewer,Xephyr',
description: 'Comma delimited list of applications ressources or class allowed to issue X11 grabs in Xwayland'
)
+
+option('libcapng',
+ type: 'feature',
+ value: 'auto',
+ description: 'Enable libcap-ng support'
+)
diff --git a/src/core/main.c b/src/core/main.c
index 7f4f666d2..b27968f13 100644
--- a/src/core/main.c
+++ b/src/core/main.c
@@ -66,6 +66,10 @@
#include <girepository.h>
#endif
+#ifdef HAVE_LIBCAPNG
+#include <cap-ng.h>
+#endif
+
#if defined(HAVE_NATIVE_BACKEND) && defined(HAVE_WAYLAND)
#include <systemd/sd-login.h>
#endif /* HAVE_WAYLAND && HAVE_NATIVE_BACKEND */
@@ -673,6 +677,12 @@ meta_run (void)
if (!meta_display_open ())
meta_exit (META_EXIT_ERROR);
+#ifdef HAVE_LIBCAPNG
+ capng_clear(CAPNG_SELECT_BOTH);
+ capng_update(CAPNG_ADD, CAPNG_EFFECTIVE|CAPNG_PERMITTED, CAP_SYS_NICE);
+ capng_apply(CAPNG_SELECT_BOTH);
+#endif
+
g_main_loop_run (meta_main_loop);
meta_finalize ();
diff --git a/src/meson.build b/src/meson.build
index 90d80734f..a9fffa2c2 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -18,6 +18,7 @@ mutter_pkg_deps = [
glib_dep,
gsettings_desktop_schemas_dep,
gtk3_dep,
+ libcapng_dep,
pango_dep,
]
--
2.23.0