[Ftp-release] Announcing dbus 1.14.4 (security update)

Simon McVittie smcv at collabora.com
Wed Oct 5 14:04:59 UTC 2022

dbus is the reference implementation of D-Bus, a message bus for
communication between applications and system services.

This is a security update for the dbus 1.14.x stable branch, fixing
denial-of-service issues (CVE-2022-42010, -42011, -42012) and applying
security hardening (dbus#416).

git tag: dbus-1.14.4

Behaviour changes:

• On Linux, dbus-daemon and other uses of DBusServer now create a
  path-based Unix socket, unix:path=..., when asked to listen on a
  unix:tmpdir=... address. This makes unix:tmpdir=... equivalent to
  unix:dir=... on all platforms.
  Previous versions would have created an abstract socket, unix:abstract=...,
  in this situation.
  This change primarily affects the well-known session bus when run via
  dbus-launch(1) or dbus-run-session(1). The user bus, enabled by configuring
  dbus with --enable-user-session and running it on a systemd system,
  already used path-based Unix sockets and is unaffected by this change.
  This behaviour change prevents a sandbox escape via the session bus socket
  in sandboxing frameworks that can share the network namespace with the host
  system, such as Flatpak.
  This change might cause a regression in situations where the abstract socket
  is intentionally shared between the host system and a chroot or container,
  such as some use-cases of schroot(1). That regression can be resolved by
  using a bind-mount to share either the D-Bus socket, or the whole /tmp
  directory, with the chroot or container.
  (dbus#416, Simon McVittie)

Denial of service fixes:

Evgeny Vereshchagin discovered several ways in which an authenticated
local attacker could cause a crash (denial of service) in
dbus-daemon --system or a custom DBusServer. In uncommon configurations
these could potentially be carried out by an authenticated remote attacker.

• An invalid array of fixed-length elements where the length of the array
  is not a multiple of the length of the element would cause an assertion
  failure in debug builds or an out-of-bounds read in production builds.
  This was a regression in version 1.3.0.
  (dbus#413, CVE-2022-42011; Simon McVittie)

• A syntactically invalid type signature with incorrectly nested parentheses
  and curly brackets would cause an assertion failure in debug builds.
  Similar messages could potentially result in a crash or incorrect message
  processing in a production build, although we are not aware of a practical
  example. (dbus#418, CVE-2022-42010; Simon McVittie)

• A message in non-native endianness with out-of-band Unix file descriptors
  would cause a use-after-free and possible memory corruption in production
  builds, or an assertion failure in debug builds. This was a regression in
  version 1.3.0. (dbus#417, CVE-2022-42012; Simon McVittie)

Simon McVittie, Collabora Ltd. / Debian
on behalf of the dbus maintainers

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