1.8.12-1debian/1.8.12-1

2 files changed, 44 insertions, 0 deletions

diff --git a/debian/changelog b/debian/changelog
index e9c6bd32..c3877ae8 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,15 @@
+dbus (1.8.12-1) unstable; urgency=medium
+
+  * New upstream release 1.8.12
+    - increase auth_timeout from 5 seconds back to 30 seconds since it
+      appears to cause slow or failed boot on some systems, reverting a
+      change in 1.8.8 (Closes: #769069)
+    - add a README.Debian to the dbus package documenting how
+      sysadmins with hostile local users can get the lower timeout back,
+      if their systems are fast enough to boot correctly like that
+
+ -- Simon McVittie <smcv@debian.org>  Mon, 24 Nov 2014 13:46:01 +0000
+
 dbus (1.8.10-1) unstable; urgency=medium
 
   * New upstream release 1.8.10
diff --git a/debian/dbus.README.Debian b/debian/dbus.README.Debian
new file mode 100644
index 00000000..60b7df4e
--- /dev/null
+++ b/debian/dbus.README.Debian
@@ -0,0 +1,32 @@
+Adjusting limits to mitigate denial of service
+==============================================
+
+'dbus-daemon --system' has several arbitrary limits which are a trade-off
+between working correctly when not under attack, and preventing local
+denial of service attacks. System administrators with particularly hostile
+local users should review these limits and tune them if necessary.
+
+In particular, the fix for CVE-2014-3639 in dbus-1.8.8 makes it difficult
+for local users to prevent connections completely, but they can still
+introduce a delay which increases with larger authentication timeout
+(auth_timeout) values, by opening many parallel connections from
+different processes and never completing the authentication handshake.
+As a result, dbus 1.8.8 also reduced the auth_timeout from 30 seconds
+to 5 seconds to mitigate this delay. However, this change resulted in
+boot failures on some systems because systemd could not authenticate
+sufficiently quickly while the system was busy, and was reverted in 1.8.12.
+
+On fast systems with hostile local users, administrators can reduce this
+delay by returning to the 5 second timeout (or any other value in
+milliseconds), by saving this as /etc/dbus-1/system-local.conf or a file
+matching /etc/dbus-1/system.d/*.conf:
+
+  <busconfig>
+    <limit name="auth_timeout">5000</limit>
+  </busconfig>
+
+If applying this change, please reboot several times and check the
+syslog or Journal for messages containing "Connection has not authenticated
+soon enough, closing it". Seeing that message while not subject to a
+denial-of-service attack indicates that the auth_timeout has been set
+too short.