Move the call to bus_selinux_allows_send() after the call to
bus_connections_check_reply().
This allows LSMs to know if the message is a reply and whether or not it
was requested.
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>
When an AppArmor confined process wants to acquire a well-known name, a
check is performed to see if the action should be allowed.
The check is based on the connection's label, the bus type, and the name
being requested.
An example AppArmor rule that would allow the name
"com.example.ExampleName" to be acquired on the system bus would be:
dbus bind bus=system name=com.example.ExampleName,
To let a process acquire any name on any bus, the rule would be:
dbus bind,
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=75113
Signed-off-by: John Johansen <john.johansen@canonical.com>
[tyhicks: Use BusAppArmorConfinement, bug fixes, cleanup, commit msg]
[tyhicks: initialize reserved area at the start of the query string]
[tyhicks: Use empty string for NULL bustypes when building queries]
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Reviewed-by: Simon McVittie <simon.mcvittie@collabora.co.uk>
When processes connect the bus, the AppArmor confinement context should
be stored for later use when checks are to be done during message
sending/receiving, acquire a name, and eavesdropping.
Code outside of apparmor.c will need to initialize and unreference the
confinement context, so bus_apparmor_confinement_unref() can no longer
be a static function.
[Move bus_apparmor_confinement_unref back to its old location for
a more reasonable diff -smcv]
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=75113
Reviewed-by: Simon McVittie <simon.mcvittie@collabora.co.uk>
During dbus-daemon initialization, the AppArmor confinement context
should be stored for later use when checks are to be done on messages
to/from the bus itself.
AppArmor confinement contexts are documented in aa_getcon(2). They
contain a confinement string and a mode string. The confinement string
is typically the name of the AppArmor profile confining a given process.
The mode string gives the current enforcement mode of the process
confinement. For example, it may indicate that the confinement should be
enforced or it may indicate that the confinement should allow all
actions with the caveat that actions which would be denied should be
audited.
It is important to note that libapparmor mallocs a single buffer to
store the con and mode strings and separates them with a NUL terminator.
Because of this, only con should be freed.
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=75113
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
[smcv: use BUS_SET_OOM]
[smcv: dbus_set_error doesn't need extra newlines]
Reviewed-by: Simon McVittie <simon.mcvittie@collabora.co.uk>
Reviewed-by: Tyler Hicks <tyhicks@canonical.com>
When starting dbus-daemon, autodetect AppArmor kernel support and use
the results from parsing the busconfig to determine if mediation should
be enabled.
In the busconfig, "enabled" means that kernel support is autodetected
and, if available, AppArmor mediation occurs in dbus-daemon. In
"enabled" mode, if kernel support is not detected, mediation is
disabled. "disabled" means that mediation does not occur. "required"
means that kernel support must be detected for dbus-daemon to start.
Additionally, when libaudit support is built into dbus-daemon, the
AppArmor initialization routines set up the audit connection.
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=75113
Signed-off-by: John Johansen <john.johansen@canonical.com>
[tyhicks: Honor enforcement modes and detect AppArmor dbus rule support]
[tyhicks: fix unreachable return when AppArmor support is built]
[tyhicks: make bus_apparmor_full_init() able to raise a DBusError]
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
[smcv: _bus_apparmor_aa_supports_dbus: document necessary kernel API guarantee]
[smcv: bus_apparmor_pre_init: distinguish between OOM and AppArmor not enabled]
[smcv: document why we open() and not just stat()]
Reviewed-by: Simon McVittie <simon.mcvittie@collabora.co.uk>
Reviewed-by: Tyler Hicks <tyhicks@canonical.com>
The <apparmor> element can contain a single mode attribute that has one
of three values:
"enabled"
"disabled"
"required"
"enabled" means that kernel support is autodetected and, if available,
AppArmor mediation occurs in dbus-daemon. If kernel support is not
detected, mediation is disabled. "disabled" means that mediation does
not occur. "required" means that kernel support must be detected for
dbus-daemon to start.
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>
AppArmor support can be configured at build time with --enable-apparmor
and --disable-apparmor. By default, the build time decision is
automatically decided by checking if a sufficient libapparmor is
available.
A minimum required libapparmor is version 2.8.95.
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=75113
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
[smcv: avoid potential non-portability from "test EXPR -a EXPR"]
Reviewed-by: Simon McVittie <simon.mcvittie@collabora.co.uk>
Reviewed-by: Tyler Hicks <tyhicks@canonical.com>
This guide gives some pointers on how to write D-Bus APIs which are nice
to use.
It adds an optional dependency on Ducktype and yelp-build from
yelp-tools. These are used when available, but are not required unless
--enable-ducktype-docs is passed to configure. They are required for
uploading the docs, however.
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=88994
Reviewed-by: Simon McVittie <simon.mcvittie@collabora.co.uk>
- change "ref serial" to "in_reply_to" (avoiding whitespace for easy
visual parsing)
- prefix with # to clarify that these are not part of the data
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=89165
Reviewed-by: Ralf Habacker <ralf.habacker@freenet.de>
dbus-send could already pretty-print bytestrings that do not have
\0 termination, but those are awkward to work with (they need copying),
so they are now discouraged. Teach it to print bytestrings that
do have \0 termination as well.
In the process, rewrite this part of the message parser
to use dbus_message_iter_get_fixed_array(), which is the Right way
to get arrays of numbers out of a message.
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=89109
Reviewed-by: Philip Withnall <philip.withnall@collabora.co.uk>
This interface contains methods 'EnableVerbose' and 'DisableVerbose'
to control verbose mode on daemon runtime.
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=88896
Reviewed-by: Simon McVittie <simon.mcvittie@collabora.co.uk>
dbus_connection_get_windows_user is documented to return TRUE but
put NULL in its argument if OOM is reached.
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=89041
Reviewed-by: Ralf Habacker <ralf.habacker@freenet.de>
It was relying on a higher-than-default fd limit; cut it down to
more than 256 but rather less than 1024, since the default Linux
limit is 1024 fds per user.
Also automatically skip this test if our rlimit is too small.
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=88998
Reviewed-by: Philip Withnall <philip.withnall@collabora.co.uk>
Without this code change, non-systemd processes can make dbus-daemon
think systemd failed to activate a system service, resulting in an
error reply back to the requester. In practice we can address this in
system.conf by only allowing root to forge these messages, but this
check is the real solution, particularly on systems where root is
not all-powerful.
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=88811
Reviewed-by: Alban Crequy
Reviewed-by: David King
Reviewed-by: Philip Withnall
We need this, or something equivalent, to address CVE-2015-0245 via
code changes.
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=88811
Reviewed-by: Alban Crequy
Reviewed-by: David King
Reviewed-by: Philip Withnall
test-marshal and test-syntax need the
$(testutils_shared_if_possible_cppflags), so that they will get the
$(static_cflags) when we are not linking to dbus-glib.
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=88980
Reviewed-by: Ralf Habacker <ralf.habacker@freenet.de>
Move the dbus_connection_add_filter() call further up as a precaution,
because it isn't safe for a monitor to not have a filter that
swallows all messages.
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=46787
Reviewed-by: Philip Withnall <philip.withnall@collabora.co.uk>
This includes most of the situations I could think of:
* method call on dbus-daemon and response
* NameOwnerChanged
* NameAcquired, NameLost (although I'm not 100% sure these should
get captured, since they're redundant with NameOwnerChanged)
* unicast message is allowed through
* unicast message is rejected by no-sending or no-receiving policy
* broadcast is allowed through
* broadcast is rejected by no-sending policy (the error reply
is also captured)
* broadcast is rejected by no-receiving policy (there is no error
reply)
* message causing service activation, and the message telling systemd
to do the actual activation
* systemd reporting that activation failed
It does not cover:
* sending a message to dbus-daemon, then provoking a reply, then
dbus-daemon does not allow itself to send the reply due to its
own security policy
This is such an obscure corner case that I'm not even convinced it's
testable without dropping down into lower-level socket manipulation:
dbus-daemon's replies are always assumed to be requested replies,
and replies contain so little other metadata that I think we can
only forbid them by forbidding all method replies. If we do that,
the reply to Hello() won't arrive and the client-side connection will
not become active.
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=46787
Reviewed-by: Philip Withnall <philip.withnall@collabora.co.uk>
