Mediation of processes eavesdropping

When an AppArmor confined process wants to eavesdrop on a bus, a check
is performed to see if the action should be allowed.

The check is based on the connection's label and the bus type.

This patch adds a new hook, which was not previously included in the
SELinux mediation, to mediate eavesdropping from
bus_driver_handle_add_match().

A new function is added to bus/signals.c to see if a match rule is an
eavesdropping rule since the rule flags field is private to signals.c.

An example AppArmor rule that would allow a process to eavesdrop on the
session bus would be:

  dbus eavesdrop bus=session,

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=75113
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Reviewed-by: Simon McVittie <simon.mcvittie@collabora.co.uk>

1 files changed, 2 insertions, 0 deletions

diff --git a/bus/signals.h b/bus/signals.h
index d19fc7c5..0edfb07e 100644
--- a/bus/signals.h
+++ b/bus/signals.h
@@ -73,6 +73,8 @@ dbus_bool_t bus_match_rule_set_arg          (BusMatchRule     *rule,
 void bus_match_rule_set_client_is_eavesdropping (BusMatchRule     *rule,
                                                  dbus_bool_t is_eavesdropping);
 
+dbus_bool_t bus_match_rule_get_client_is_eavesdropping (BusMatchRule *rule);
+
 BusMatchRule* bus_match_rule_parse (DBusConnection   *matches_go_to,
                                     const DBusString *rule_text,
                                     DBusError        *error);