** Description changed:
The auditd daemon is not part of the default phone images. At the kernel
level, the audit_enabled variable remains 0 until an auditd daemon
registers itself. There is a bug in old kernels that causes
AUDIT_USER_AVC messages to be ignored when audit_enabled is 0. I fixed
the bug several years ago and marked the patch for the stable tree but
the phone kernels (mako, at least) did not pull in the patch. The
upstream commit id is:
0868a5e150bc4c47e7a003367cd755811eb41e0b
What this means for our phone images is that any denial messages from
the system D-Bus daemon are dropped instead of being properly routed to
the syslog. This results in headaches for debugging app confinement
denials.
== Verification Steps ==
# Load an AppArmor profile for testing
$ echo "profile test { file, signal, unix, }" | sudo apparmor_parser -rq
+
# Verify that we can talk to the system bus
$ dbus-send --print-reply --system --dest=org.freedesktop.DBus
/org/freedesktop/DBus org.freedesktop.DBus.ListNames
method return sender=org.freedesktop.DBus -> dest=:1.90 reply_serial=2
- array [
- string "org.freedesktop.DBus"
- ...
+ array [
+ string "org.freedesktop.DBus"
+ ...
+
# Clear the dmesg buffer
$ sudo dmesg -C
+
# Attempt to talk to the system bus under confinement
$ aa-exec -p test -- dbus-send --print-reply --system
--dest=org.freedesktop.DBus /org/freedesktop/DBus org.freedesktop.DBus.ListNames
Failed to open connection to "system" message bus: An AppArmor policy
prevents this sender from sending this message to this recipient;
type="method_call", sender="(null)" (inactive) interface="org.freedesktop.DBus"
member="Hello" error name="(unset)" requested_reply="0"
destination="org.freedesktop.DBus" (bus)
+
# We should now see an AppArmor denial in the dmesg output.
# Successful fix verification *must* show the denial from the D-Bus daemon.
$ sudo dmesg | grep DENIED
+ [ 187.737219] type=1107 audit(1438385684.065:149): pid=826 uid=102
auid=4294967295 ses=4294967295 msg='apparmor="DENIED"
operation="dbus_method_call" bus="system" path="/org/freedesktop/DBus"
interface="org.freedesktop.DBus" member="Hello" mask="send"
name="org.freedesktop.DBus" pid=6721 label="test" peer_label="unconfined"
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https://bugs.launchpad.net/bugs/1473584
Title:
AUDIT_USER_AVC messages are not printk'ed when auditd is not running
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