Description
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).
Also default auth_timeout that was changed from 30s to 5s in MGASA-2014-0395,
and raised to 20s in MGAA-2014-0182 is now changed back to 30s as there
still are reports about failing dbus connections.