4.4 - MDVSA-2015:176

Updated dbus packages fix multiple vulnerabilities:

A denial of service vulnerability in D-Bus before 1.6.20 allows a local attacker to cause a bus-activated service that is not currently running to attempt to start, and fail, denying other users access to this service Additionally, in highly unusual environments the same flaw could lead to a side channel between processes that should not be able to communicate (CVE-2014-3477).

A flaw was reported in D-Bus's file descriptor passing feature. A local attacker could use this flaw to cause a service or application to disconnect from the bus, typically resulting in that service or application exiting (CVE-2014-3532).

A flaw was reported in D-Bus's file descriptor passing feature. A local attacker could use this flaw to cause an invalid file descriptor to be forwarded to a service or application, causing it to disconnect from the bus, typically resulting in that service or application exiting (CVE-2014-3533).

On 64-bit platforms, file descriptor passing could be abused by local users to cause heap corruption in dbus-daemon, leading to a crash, or potentially to arbitrary code execution (CVE-2014-3635).

A denial-of-service vulnerability in dbus-daemon allowed local attackers to prevent new connections to dbus-daemon, or disconnect existing clients, by exhausting descriptor limits (CVE-2014-3636).

Malicious local users could create D-Bus connections to dbus-daemon which could not be terminated by killing the participating processes, resulting in a denial-of-service vulnerability (CVE-2014-3637).

dbus-daemon suffered from a denial-of-service vulnerability in the code which tracks which messages expect a reply, allowing local attackers to reduce the performance of dbus-daemon (CVE-2014-3638).

dbus-daemon did not properly reject malicious connections from local users, resulting in a denial-of-service vulnerability (CVE-2014-3639).

The patch issued by the D-Bus maintainers for CVE-2014-3636 was based on incorrect reasoning, and does not fully prevent the attack described as CVE-2014-3636 part A, which is repeated below. Preventing that attack requires raising the system dbus-daemon's RLIMIT_NOFILE (ulimit -n) to a higher value.

By queuing up the maximum allowed number of fds, a malicious sender could reach the system dbus-daemon's RLIMIT_NOFILE (ulimit -n, typically 1024 on Linux). This would act as a denial of service in two ways:

* new clients would be unable to connect to the dbus-daemon

* when receiving a subsequent message from a non-malicious client that contained a fd, dbus-daemon would receive the MSG_CTRUNC flag, indicating that the list of fds was truncated; kernel fd-passing APIs do not provide any way to recover from that, so dbus-daemon responds to MSG_CTRUNC by disconnecting the sender, causing denial of service to that sender.

This update resolves the issue (CVE-2014-7824).

non-systemd processes can make dbus-daemon think systemd failed to activate a system service, resulting in an error reply back to the requester, causing a local denial of service (CVE-2015-0245).