Após uma instalação nova do Kubuntu 24.04.1, substituí o Firefox pela versão do pacote deb. O Firefox me recebeu com um aviso:
Alguns dos recursos de segurança do Firefox podem oferecer menos proteção no seu sistema operacional atual. Como corrigir esse problema
Tentei seguir as instruções no link fornecido sem muita sorte, então percebi que já tenho um perfil do AppArmor para o Firefox:
$ cat /etc/apparmor.d/firefox
# This profile allows everything and only exists to give the
# application a name instead of having the label "unconfined"
abi <abi/4.0>,
include <tunables/global>
profile firefox /{usr/lib/firefox{,-esr,-beta,-devedition,-nightly},opt/firefox}/firefox{,-esr,-bin} flags=(unconfined) {
userns,
# Site-specific additions and overrides. See local/README for details.
include if exists <local/firefox>
}
Este perfil parece vir do apparmor
pacote:
$ dpkg -S /etc/apparmor.d/firefox
apparmor: /etc/apparmor.d/firefox
$ apt list apparmor
Listing... Done
apparmor/noble-updates,now 4.0.1really4.0.1-0ubuntu0.24.04.3 amd64 [installed,automatic]
E então vi outro perfil em usr.bin.firefox:
$ cat /etc/apparmor.d/usr.bin.firefox
# vim:syntax=apparmor
# Author: Jamie Strandboge <[email protected]>
# Declare an apparmor variable to help with overrides
@{MOZ_LIBDIR}=/usr/lib/firefox
#include <tunables/global>
# We want to confine the binaries that match:
# /usr/lib/firefox/firefox
# /usr/lib/firefox/firefox
# but not:
# /usr/lib/firefox/firefox.sh
profile firefox /usr/lib/firefox/firefox{,*[^s][^h]} {
#include <abstractions/audio>
#include <abstractions/cups-client>
#include <abstractions/dbus-strict>
#include <abstractions/dbus-session-strict>
#include <abstractions/dconf>
#include <abstractions/fcitx>
#include <abstractions/gnome>
#include <abstractions/ibus>
#include <abstractions/mesa>
#include <abstractions/nameservice>
#include <abstractions/openssl>
#include <abstractions/p11-kit>
#include <abstractions/ubuntu-unity7-base>
#include <abstractions/ubuntu-unity7-launcher>
#include <abstractions/dbus-accessibility-strict>
dbus (send)
bus=session
peer=(name=org.a11y.Bus),
dbus (receive)
bus=session
interface=org.a11y.atspi**,
dbus (receive, send)
bus=accessibility,
# for networking
network inet stream,
network inet6 stream,
@{PROC}/[0-9]*/net/arp r,
@{PROC}/[0-9]*/net/if_inet6 r,
@{PROC}/[0-9]*/net/ipv6_route r,
@{PROC}/[0-9]*/net/dev r,
@{PROC}/[0-9]*/net/wireless r,
dbus (send)
bus=system
path=/org/freedesktop/NetworkManager
member=state,
dbus (receive)
bus=system
path=/org/freedesktop/NetworkManager,
# used by third_party/rust/audio_thread_priority
dbus (send)
bus=system
path=/org/freedesktop/RealtimeKit1,
# should maybe be in abstractions
/etc/ r,
/etc/mime.types r,
/etc/mailcap r,
/etc/xdg/*buntu/applications/defaults.list r, # for all derivatives
/etc/xfce4/defaults.list r,
/usr/share/xubuntu/applications/defaults.list r,
owner @{HOME}/.local/share/applications/defaults.list r,
owner @{HOME}/.local/share/applications/mimeapps.list r,
owner @{HOME}/.local/share/applications/mimeinfo.cache r,
/var/lib/snapd/desktop/applications/mimeinfo.cache r,
/var/lib/snapd/desktop/applications/*.desktop r,
owner /tmp/** m,
owner /var/tmp/** m,
owner /{,var/}run/shm/shmfd-* rw,
owner /{dev,run}/shm/org.{chromium,mozilla}.* rwk,
owner /{dev,run}/shm/wayland.mozilla.ipc.[0-9]* rw,
/tmp/.X[0-9]*-lock r,
/etc/udev/udev.conf r,
# Doesn't seem to be required, but noisy. Maybe allow 'r' for 'b*' if needed.
# Possibly move to an abstraction if anything else needs it.
deny /run/udev/data/** r,
# let the shell know we launched something
dbus (send)
bus=session
interface=org.gtk.gio.DesktopAppInfo
member=Launched,
/etc/timezone r,
/etc/wildmidi/wildmidi.cfg r,
# firefox specific
/etc/firefox*/ r,
/etc/firefox*/** r,
/etc/xul-ext/** r,
/etc/xulrunner-2.0*/ r,
/etc/xulrunner-2.0*/** r,
/etc/gre.d/ r,
/etc/gre.d/* r,
# noisy
deny @{MOZ_LIBDIR}/** w,
deny /usr/lib/firefox-addons/** w,
deny /usr/lib/xulrunner-addons/** w,
deny /usr/lib/xulrunner-*/components/*.tmp w,
deny /.suspended r,
deny /boot/initrd.img* r,
deny /boot/vmlinuz* r,
deny /var/cache/fontconfig/ w,
deny @{HOME}/.local/share/recently-used.xbel r,
# TODO: investigate
deny /usr/bin/gconftool-2 x,
# These are needed when a new user starts firefox and firefox.sh is used
@{MOZ_LIBDIR}/** ixr,
/usr/bin/basename ixr,
/usr/bin/dirname ixr,
/usr/bin/pwd ixr,
/sbin/killall5 ixr,
/bin/which ixr,
/usr/bin/tr ixr,
@{PROC}/ r,
@{PROC}/[0-9]*/cmdline r,
@{PROC}/[0-9]*/mountinfo r,
@{PROC}/[0-9]*/stat r,
owner @{PROC}/[0-9]*/task/[0-9]*/stat r,
@{PROC}/[0-9]*/status r,
@{PROC}/filesystems r,
@{PROC}/sys/vm/overcommit_memory r,
# prevent crash LP: #1931602
/sys/devices/pci[0-9]*/**/{uevent,resource,irq,class} r,
/sys/devices/platform/**/uevent r,
/sys/devices/pci*/**/{busnum,idVendor,idProduct} r,
/sys/devices/pci*/**/{,subsystem_}device r,
/sys/devices/pci*/**/{,subsystem_}vendor r,
/sys/devices/system/node/node[0-9]*/meminfo r,
owner @{HOME}/.cache/thumbnails/** rw,
/etc/mtab r,
/etc/fstab r,
# Needed for the crash reporter
owner @{PROC}/[0-9]*/environ r,
owner @{PROC}/[0-9]*/auxv r,
/etc/lsb-release r,
/usr/bin/expr ix,
/sys/devices/system/cpu/ r,
/sys/devices/system/cpu/** r,
# about:memory
owner @{PROC}/[0-9]*/statm r,
owner @{PROC}/[0-9]*/smaps r,
# allow access to documentation and other files the user may want to look
# at in /usr and /opt
/usr/ r,
/usr/** r,
/opt/ r,
/opt/** r,
# so browsing directories works
/ r,
/**/ r,
# Default profile allows downloads to ~/Downloads and uploads from ~/Public
owner @{HOME}/ r,
owner @{HOME}/Public/ r,
owner @{HOME}/Public/* r,
owner @{HOME}/Downloads/ r,
owner @{HOME}/Downloads/* rw,
# per-user firefox configuration
owner @{HOME}/.{firefox,mozilla}/ rw,
owner @{HOME}/.{firefox,mozilla}/** rw,
owner @{HOME}/.{firefox,mozilla}/**/*.{db,parentlock,sqlite}* k,
owner @{HOME}/.{firefox,mozilla}/plugins/** rm,
owner @{HOME}/.{firefox,mozilla}/**/plugins/** rm,
owner @{HOME}/.gnome2/firefox* rwk,
owner @{HOME}/.cache/mozilla/{,firefox/} rw,
owner @{HOME}/.cache/mozilla/firefox/** rw,
owner @{HOME}/.cache/mozilla/firefox/**/*.sqlite* k,
owner @{HOME}/.config/gtk-3.0/bookmarks r,
owner @{HOME}/.config/dconf/user w,
owner /{,var/}run/user/*/dconf/user w,
dbus (send)
bus=session
path=/org/gnome/GConf/Server
member=GetDefaultDatabase
peer=(label=unconfined),
dbus (send)
bus=session
path=/org/gnome/GConf/Database/*
member={AddMatch,AddNotify,AllEntries,LookupExtended,RemoveNotify}
peer=(label=unconfined),
dbus (send)
bus=session
path=/org/gtk/vfs/mounttracker
interface=org.gtk.vfs.MountTracker
member=ListMountableInfo
peer=(label=unconfined),
# Allow access to xdg-desktop-portal and xdg-document-portal (LP: #1974449)
dbus (receive, send)
bus=session
interface=org.freedesktop.portal.*
path=/org/freedesktop/portal/{desktop,documents}{,/**}
peer=(label=unconfined),
dbus (receive, send)
bus=session
interface=org.freedesktop.DBus.Properties
path=/org/freedesktop/portal/{desktop,documents}{,/**}
peer=(label=unconfined),
# Allow access to the Fcitx portal, supported by fcitx/fcitx5
dbus (send)
bus=session
path=/{,org/freedesktop/portal/}inputmethod
interface=org.fcitx.Fcitx.InputMethod1
member={CreateInputContext,Version}
peer=(name=org.freedesktop.portal.Fcitx),
dbus (send, receive)
bus=session
path=/{,org/freedesktop/portal/}inputcontext/**
interface=org.fcitx.Fcitx.InputContext1,
# Allow remote control when running on Wayland
dbus (send)
bus=session
path=/org/freedesktop/DBus
interface=org.freedesktop.DBus
member=RequestName
peer=(name=org.freedesktop.DBus),
dbus (bind)
bus=session
name=org.mozilla.firefox.*,
dbus (send, receive)
bus=session
path=/org/mozilla/firefox/Remote
interface=org.mozilla.firefox
member=OpenURL
peer=(label=firefox),
# gnome-session
dbus (send)
bus=session
path=/org/gnome/SessionManager
interface=org.gnome.SessionManager
member={Inhibit,Uninhibit}
peer=(label=unconfined),
# unity screen API
dbus (send)
bus=system
interface="org.freedesktop.DBus.Introspectable"
path="/com/canonical/Unity/Screen"
member="Introspect"
peer=(label=unconfined),
dbus (send)
bus=system
interface="com.canonical.Unity.Screen"
path="/com/canonical/Unity/Screen"
member={keepDisplayOn,removeDisplayOnRequest}
peer=(label=unconfined),
# freedesktop.org ScreenSaver
dbus (send)
bus=session
path=/{,org/freedesktop/,org.gnome/}Screen{s,S}aver
interface=org.freedesktop.ScreenSaver
member={Inhibit,UnInhibit,SimulateUserActivity}
peer=(label=unconfined),
# gnome, kde and cinnamon screensaver
dbus (send)
bus=session
path=/{,ScreenSaver}
interface=org.{gnome.ScreenSaver,kde.screensaver,cinnamon.ScreenSaver}
member=SimulateUserActivity
peer=(label=unconfined),
# UPower
dbus (send)
bus=system
path=/org/freedesktop/UPower
interface=org.freedesktop.UPower
member=EnumerateDevices
peer=(label=unconfined),
# File browser
dbus (send)
bus=session
interface=org.freedesktop.FileManager1
path=/org/freedesktop/FileManager1
member=ShowItems,
#
# Extensions
# /usr/share/.../extensions/... is already covered by '/usr/** r', above.
# Allow 'x' for downloaded extensions, but inherit policy for safety
owner @{HOME}/.mozilla/**/extensions/** mixr,
deny @{MOZ_LIBDIR}/update.test w,
deny /usr/lib/mozilla/extensions/**/ w,
deny /usr/lib/xulrunner-addons/extensions/**/ w,
deny /usr/share/mozilla/extensions/**/ w,
deny /usr/share/mozilla/ w,
# Miscellaneous (to be abstracted)
# Ideally these would use a child profile. They are all ELF executables
# so running with 'Ux', while not ideal, is ok because we will at least
# benefit from glibc's secure execute.
/usr/bin/mkfifo Uxr, # investigate
/bin/ps Uxr,
/bin/uname Uxr,
/usr/bin/lsb_release Cxr -> lsb_release,
profile lsb_release {
#include <abstractions/base>
#include <abstractions/python>
/usr/bin/lsb_release r,
/bin/dash ixr,
/usr/bin/dpkg-query ixr,
/usr/include/python2.[4567]/pyconfig.h r,
/etc/lsb-release r,
/etc/debian_version r,
/usr/share/distro-info/*.csv r,
/var/lib/dpkg/** r,
/usr/local/lib/python3.[0-9]/dist-packages/ r,
/usr/bin/ r,
/usr/bin/python3.[0-9] mr,
# file_inherit
deny /tmp/gtalkplugin.log w,
}
# Addons
#include <abstractions/ubuntu-browsers.d/firefox>
# Site-specific additions and overrides. See local/README for details.
#include <local/usr.bin.firefox>
}
Que vem do próprio pacote do Firefox:
$ dpkg -S /etc/apparmor.d/usr.bin.firefox
firefox: /etc/apparmor.d/usr.bin.firefox
$ apt list firefox
Listing... Done
firefox/noble,now 135.0+build2-0ubuntu0.24.04.1~mt2 amd64 [installed]
Neste ponto, parecia que o usr.bin.firefox
arquivo tinha prioridade, então editei /etc/apparmor.d/local/usr.bin.firefox
assim:
$ cat /etc/apparmor.d/local/usr.bin.firefox
userns,
Mas o aviso não desaparece a menos que eu adicione algo flags=(unconfined)
ao perfil, o que, até onde eu entendo, significa que nenhuma restrição ao processo será aplicada.
Então a questão é: é possível permitir que o Firefox use namespaces de usuário não privilegiados para sandboxing sem usar o unconfined
sinalizador? Em outras palavras, como posso aplicar regras do AppArmor e ainda permitir userns
privilégios?