Bugzilla – Bug 904017
VUL-0: CVE-2014-7824: dbus-1: Denial of service via incomplete fix for CVE-2014-3636
Last modified: 2015-04-08 12:38:49 UTC
See bnc#896453 for CVE-2014-3636. Right now there is no fixed CRD date, only " I intend to address it in dbus 1.8.10 within the next few days". Looks like SLE 12 and all openSUSE variants are affected. Date: Tue, 04 Nov 2014 13:20:44 +0000 From: Simon McVittie <simon.mcvittie@collabora.co.uk> To: distros@vs.openwall.org 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. To avoid propagating that higher limit to activatable system services, it is desirable to start the system dbus-daemon as root so it can store its previous limit, raise its limit, drop root privileges (which its default configuration will do automatically), and restore the previous limit before launching activatable services. Some operating system distributions, such as anything using the upstream-supplied systemd units, start the system dbus-daemon as root already; others, such as Debian 7, currently start the system dbus-daemon under its less privileged uid and will need minor modifications to their init scripts. Suggested patches are attached. Patch 0001 is not strictly required, but if it is skipped, it will be necessary to replace each occurrence of DBUS_SYSTEM_LOG_WARNING with DBUS_SYSTEM_LOG_INFO in patch 0002. Tracked as: https://bugs.freedesktop.org/show_bug.cgi?id=85105 Category: related to CWE-774: Allocation of File Descriptors or Handles Without Limits or Throttling Impact: local denial of service Access required: local Versions believed to be vulnerable: dbus >= 1.3.0 Credit: discovered by Simon McVittie at Collabora Ltd. Attack details (repeating CVE-2014-3636 part A): 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 sende
Created attachment 612484 [details] Patch for the issue
Created attachment 612485 [details] Additional log level Patch 0001 is not strictly required, but if it is skipped, it will be necessary to replace each occurrence of DBUS_SYSTEM_LOG_WARNING with DBUS_SYSTEM_LOG_INFO in patch 0002.
Created attachment 612756 [details] updated patch From: Simon McVittie <simon.mcvittie@collabora.co.uk> Proposed release date is Monday 10th, 16:00 UTC. I have replaced the original suggested patch with this one, which mentions the CVE ID and does not need additional patches applied first. This is hopefully going to be the only change between dbus 1.8.8 and 1.8.10, other than the usual NEWS/configure.ac noise.
Embargo is over
This is an autogenerated message for OBS integration: This bug (904017) was mentioned in https://build.opensuse.org/request/show/260719 Factory / dbus-1 https://build.opensuse.org/request/show/260720 13.1 / dbus-1 https://build.opensuse.org/request/show/260721 13.2 / dbus-1
This is an autogenerated message for OBS integration: This bug (904017) was mentioned in https://build.opensuse.org/request/show/260731 12.3 / dbus-1
This is an autogenerated message for OBS integration: This bug (904017) was mentioned in https://build.opensuse.org/request/show/260747 13.1 / dbus-1
SUSE-SU-2014:1724-1: An update that fixes two vulnerabilities is now available. Category: security (moderate) Bug References: 904017 CVE References: CVE-2014-3636,CVE-2014-7824 Sources used: SUSE Linux Enterprise Software Development Kit 12 (src): dbus-1-1.8.12-6.1, dbus-1-x11-1.8.12-6.5 SUSE Linux Enterprise Server 12 (src): dbus-1-1.8.12-6.1, dbus-1-x11-1.8.12-6.5 SUSE Linux Enterprise Desktop 12 (src): dbus-1-1.8.12-6.1, dbus-1-x11-1.8.12-6.5
all updates released