The 8021x offloading procedure still does EAP in userspace which
negotiates the PMK. The kernel then expects to obtain this PMK
from userspace by calling SET_PMK. This then allows the firmware
to begin the 4-way handshake.
Using __eapol_install_set_pmk_func to install netdev_set_pmk,
netdev now gets called into once EAP finishes and can begin
the final userspace actions prior to the firmware starting
the 4-way handshake:
- SET_PMK using PMK negotiated with EAP
- Emit SETTING_KEYS event
- netdev_connect_ok
One thing to note is that the kernel provides no way of knowing if
the 4-way handshake completed. Assuming SET_PMK/SET_STATION come
back with no errors, IWD assumes the PMK was valid. If not, or
due to some other issue in the 4-way, the kernel will send a
disconnect.
This adds a new type for 8021x offload as well as support in
building CMD_CONNECT.
As described in the comment, 8021x offloading is not particularly
similar to PSK as far as the code flow in IWD is concerned. There
still needs to be an eapol_sm due to EAP being done in userspace.
This throws somewhat of a wrench into our 'is_offload' cases. And
as such this connection type is handled specially.
The chances were extremely low, but using l_idle_oneshot
could end up causing a invalid memory access if the netdev
went down while waiting for the disconnect idle callback.
Instead netdev can keep track of the idle with l_idle_create
and remove it if the netdev goes down prior to the idle callback.
This crash was caused from the disconnect_cb being called
immediately in cases where send_disconnect was false. The
previous patch actually addressed this separately as this
flag was being set improperly which will, indirectly, fix
one of the two code paths that could cause this crash.
Still, there is a situation where send_disconnect could
be false and in this case IWD would still crash. If IWD
is waiting to queue the connect item and netdev_disconnect
is called it would result in the callback being called
immediately. Instead we can add an l_idle as to allow the
callback to happen out of scope, which is what station
expects.
Prior to this patch, the crashing behavior can be tested using
the following script (or some variant of it, your system timing
may not be the same as mine).
iwctl station wlan0 disconnect
iwctl station wlan0 connect <network1> &
sleep 0.02
iwctl station wlan0 connect <network2>
++++++++ backtrace ++++++++
0 0x7f4e1504e530 in /lib64/libc.so.6
1 0x432b54 in network_get_security() at src/network.c:253
2 0x416e92 in station_handshake_setup() at src/station.c:937
3 0x41a505 in __station_connect_network() at src/station.c:2551
4 0x41a683 in station_disconnect_onconnect_cb() at src/station.c:2581
5 0x40b4ae in netdev_disconnect() at src/netdev.c:3142
6 0x41a719 in station_disconnect_onconnect() at src/station.c:2603
7 0x41a89d in station_connect_network() at src/station.c:2652
8 0x433f1d in network_connect_psk() at src/network.c:886
9 0x43483a in network_connect() at src/network.c:1183
10 0x4add11 in _dbus_object_tree_dispatch() at ell/dbus-service.c:1802
11 0x49ff54 in message_read_handler() at ell/dbus.c:285
12 0x496d2f in io_callback() at ell/io.c:120
13 0x495894 in l_main_iterate() at ell/main.c:478
14 0x49599b in l_main_run() at ell/main.c:521
15 0x495cb3 in l_main_run_with_signal() at ell/main.c:647
16 0x404add in main() at src/main.c:490
17 0x7f4e15038b25 in /lib64/libc.so.6
The send_disconnect flag was being improperly set based only
on connect_cmd_id being zero. This does not take into account
the case of CMD_CONNECT having finished but not EAPoL. In this
case we do need to send a disconnect.
This adds a new connection type, TYPE_PSK_OFFLOAD, which
allows the 4-way handshake to be offloaded by the firmware.
Offloading will be used if the driver advertises support.
The CMD_ROAM event path was also modified to take into account
handshake offloading. If the handshake is offloaded we still
must issue GET_SCAN, but not start eapol since the firmware
takes care of this.
In the FW scan callback eapol was being stared unconditionally which
isn't correct as roaming on open networks is possible. Instead check
that a SM exists just like is done in netdev_connect_event.
This should have been updated along with the connect and roam
event separation. Since netdev_connect_event is not being
re-used for CMD_ROAM the comment did not make sense anymore.
Still, there needs to be a check to ensure we were not disconnected
while waiting for GET_SCAN to come back.
netdev_connect_event was being reused for parsing of CMD_ROAM
attributes which made some amount of sense since these events
are nearly identical, but due to the nature of firmware roaming
there really isn't much IWD needs to parse from CMD_ROAM. In
addition netdev_connect_event was getting rather complicated
since it had to handle both CMD_ROAM and CMD_CONNECT.
The only bits of information IWD needs to parse from CMD_ROAM
is the roamed BSSID, authenticator IEs, and supplicant IEs. Since
this is so limited it now makes little sense to reuse the entire
netdev_connect_event function, and intead only parse what is
needed for CMD_ROAM.
Currently netdev handles SoftMac and FullMac drivers mostly in the same
way, by building CMD_CONNECT nl80211 commands and letting the kernel
figure out the details. Exceptions to this are FILS/OWE/SAE AKMs which
are only supported on SoftMac drivers by using
CMD_AUTHENTICATE/CMD_ASSOCIATE.
Recently, basic support for SAE (WPA3-Personal) offload on FullMac cards
was introduced. When offloaded, the control flow is very different than
under typical conditions and required additional logic checks in several
places. The logic is now becoming quite complex.
Introduce a concept of a connection type in order to make it clearer
what driver and driver features are being used for this connection. In
the future, connection types can be expanded with 802.1X handshake
offload, PSK handshake offload and CMD_EXTERNAL_AUTH based SAE
connections.
Any auth proto which did not implement the assoc_timeout handler
could end up getting 'stuck' forever if there was an associate
timeout. This is because in the event of an associate timeout IWD
only sets a few flags and relies on the connect event to actually
handle the failure. The problem is a connect event never comes
if the failure was a timeout.
To fix this we can explicitly fail the connection if the auth
proto has not implemented assoc_timeout or if it returns false.
SAE offload support requires some minor tweaks to CMD_CONNECT
as well as special checks once the connect event comes in. Since
at this point we are fully connected.
Roaming on a full mac card is quite different than soft mac
and needs to be specially handled. The process starts with
the CMD_ROAM event, which tells us the driver is already
roamed and associated with a new AP. After this it expects
the 4-way handshake to be initiated. This in itself is quite
simple, the complexity comes with how this is piped into IWD.
After CMD_ROAM fires its assumed that a scan result is
available in the kernel, which is obtained using a newly
added scan API scan_get_firmware_scan. The only special
bit of this is that it does not 'schedule' a scan but simply
calls GET_SCAN. This is treated special and will not be
queued behind any other pending scan requests. This lets us
reuse some parsing code paths in scan and initialize a
scan_bss object which ultimately gets handed to station so
it can update connected_bss/bss_list.
For consistency station must also transition to a roaming state.
Since this roam is all handled by netdev two new events were
added, NETDEV_EVENT_ROAMING and NETDEV_EVENT_ROAMED. Both allow
station to transition between roaming/connected states, and ROAMED
provides station with the new scan_bss to replace connected_bss.
Since GET_STATION (and in turn GetDiagnostics) gets the most
current station info this attribute serves as a better indication
of the current signal strength. In addition full mac cards don't
appear to always have the average attribute.
If the extended feature for CQM levels was not supported no CQM
registration would happen, not even for a single level. This
caused IWD to completely lose the ability to roam since it would
only get notified when the kernel was disconnecting, around -90
dBm, not giving IWD enough time to roam.
Instead if the extended feature is not supported we can still
register for the event, just without multiple signal levels.
Handle situations where the BSS we're trying to connect to is no longer
in the kernel scan result cache. Normally, the kernel will re-scan the
target frequency if this happens on the CMD_CONNECT path, and retry the
connection.
Unfortunately, CMD_AUTHENTICATE path used for WPA3, OWE and FILS does
not have this scanning behavior. CMD_AUTHENTICATE simply fails with
a -ENOENT error. Work around this by trying a limited scan of the
target frequency and re-trying CMD_AUTHENTICATE once.
In some cases the AP can send a deauthenticate frame right after
accepting our authentication. In this case the kernel never properly
sends a CMD_CONNECT event with a failure, even though CMD_COONNECT was
used to initiate the connection. Try to work around that by detecting
that a Deauthenticate event arrives prior to any Associte or Connect
events and handle this case as a connect failure.
netdev_shutdown calls queue_destroy on the netdev_list, which in turn
calls netdev_free. netdev_free invokes the watches to notify them about
the netdev being removed. Those clients, or anything downstream can
still invoke netdev_find. Unfortunately queue_destroy is not re-entrant
safe, so netdev_find might return stale data. Fix that by using
l_queue_peek_head / l_queue_pop_head instead.
src/station.c:station_enter_state() Old State: connecting, new state:
connected
^CTerminate
src/netdev.c:netdev_free() Freeing netdev wlan1[6]
src/device.c:device_free()
Removing scan context for wdev 100000001
src/scan.c:scan_context_free() sc: 0x4ae9ca0
src/netdev.c:netdev_free() Freeing netdev wlan0[48]
src/device.c:device_free()
src/station.c:station_free()
src/netconfig.c:netconfig_destroy()
==103174== Invalid read of size 8
==103174== at 0x467AA9: l_queue_find (queue.c:346)
==103174== by 0x43ACFF: netconfig_reset (netconfig.c:1027)
==103174== by 0x43AFFC: netconfig_destroy (netconfig.c:1123)
==103174== by 0x414379: station_free (station.c:3369)
==103174== by 0x414379: station_destroy_interface (station.c:3466)
==103174== by 0x47C80C: interface_instance_free (dbus-service.c:510)
==103174== by 0x47C80C: _dbus_object_tree_remove_interface
(dbus-service.c:1694)
==103174== by 0x47C99C: _dbus_object_tree_object_destroy
(dbus-service.c:795)
==103174== by 0x409A87: netdev_free (netdev.c:770)
==103174== by 0x4677AE: l_queue_clear (queue.c:107)
==103174== by 0x4677F8: l_queue_destroy (queue.c:82)
==103174== by 0x40CDC1: netdev_shutdown (netdev.c:5089)
==103174== by 0x404736: iwd_shutdown (main.c:78)
==103174== by 0x404736: iwd_shutdown (main.c:65)
==103174== by 0x46BD61: handle_callback (signal.c:78)
==103174== by 0x46BD61: signalfd_read_cb (signal.c:104)
In the case of module_init failing due to a module that comes after
netdev, the netdev module doesn't clean up netdev_list properly.
==6254== 24 bytes in 1 blocks are still reachable in loss record 1 of 1
==6254== at 0x483777F: malloc (in
/usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==6254== by 0x4675ED: l_malloc (util.c:61)
==6254== by 0x46909D: l_queue_new (queue.c:63)
==6254== by 0x406AE4: netdev_init (netdev.c:5038)
==6254== by 0x44A7B3: iwd_modules_init (module.c:152)
==6254== by 0x404713: nl80211_appeared (main.c:171)
==6254== by 0x4713DE: process_unicast (genl.c:993)
==6254== by 0x4713DE: received_data (genl.c:1101)
==6254== by 0x46E00B: io_callback (io.c:118)
==6254== by 0x46D20C: l_main_iterate (main.c:477)
==6254== by 0x46D2DB: l_main_run (main.c:524)
==6254== by 0x46D2DB: l_main_run (main.c:506)
==6254== by 0x46D502: l_main_run_with_signal (main.c:656)
==6254== by 0x403EDB: main (main.c:490)
Fix an issue with the recent changes to signal monitoring from commit
f456501b ("station: retry roaming unless notified of a high RSSI"):
1. driver sends NL80211_CQM_RSSI_THRESHOLD_EVENT_LOW
2. netdev->cur_rssi_low changes from FALSE to TRUE
3. netdev sends NETDEV_EVENT_RSSI_THRESHOLD_LOW to station
4. on roam reassociation, cur_rssi_low is reset to FALSE
5. station still assumes RSSI is low, periodically roams
until netdev sends NETDEV_EVENT_RSSI_THRESHOLD_HIGH
6. driver sends NL80211_CQM_RSSI_THRESHOLD_EVENT_HIGH
7. netdev->cur_rssi_low doesn't change (still FALSE)
8. netdev never sends NETDEV_EVENT_RSSI_THRESHOLD_HIGH
9. station remains stuck in an infinite roaming loop
The commit in question introduced the logic in (5). Previously the
assumption in station was - like in netdev - that if the signal was
still low, the driver would send a duplicate LOW event after
reassociation. This change makes netdev follow the same new logic as
station, i.e. assume the same signal state (LOW/HIGH) until told
otherwise by the driver.
With AP now getting its own diagnostic interface it made sense
to move the netdev_station_info struct definition into its own
header which eventually can be accompanied by utilities in
diagnostic.c. These utilities can then be shared with AP and
station as needed.
This is a nl80211 dump version of netdev_get_station aimed at
AP mode. This will dump all stations, parse into
netdev_station_info structs, and call the callback for each
individual station found. Once the dump is completed the destroy
callback is called.
This adds a generalized API for GET_STATION. This API handles
calling and parsing the results into a new structure,
netdev_station_info. This results structure will hold any
data needed by consumers of netdev_get_station. A helper API
(netdev_get_current_station) was added as a convenience which
automatically passes handshake->aa as the MAC.
For now only the RSSI is parsed as this is already being
done for RSSI polling/events. Looking further more info will
be added such as rx/tx rates and estimated throughput.
In both FT or FILS EAPoL isn't used for the initial handshake and only
for the later re-keys. For FT we added the
eapol_sm_set_require_handshake mechanism to tell EAPoL to not require
the initial handshake and we can re-use it for FILS.
build_cmd_ft_authenticate and build_cmd_authenticate were virtually
identical. These have been unified into a single builder.
We were also incorrectly including ATTR_IE to every authenticate
command, which violates the spec for certain protocols, This was
removed and any auth protocols will now add any IEs that they require.
In this situation the kernel is sending a low RSSI event which netdev
picks up, but since we set netdev->connected so early the event is
forwarded to station before IWD has fully connected. Station then
tries to get a neighbor report, which may fail and cause a known
frequency scan. If this is a new network the frequency scan tries to
get any known frequencies in network_info which will be unset and
cause a segfault.
This can be avoided by only sending RSSI events when netdev->operational
is set rather than netdev->connected.
It seems some APs send the IGTK key in big endian format (it is a
uin16). The kernel rightly reports an -EINVAL error when iwd issues a
NEW_KEY with such a value, resulting in the connection being aborted.
Work around this by trying to detect big-endian key indexes and 'fixing'
them up.
In order to support AlwaysRandomizeAddress and AddressOverride, station will
set the desired address into the handshake object. Then, netdev checks if
this was done and will use that address rather than generate one.
For privacy reasons its advantageous to randomize or mask
the MAC address when connecting to networks, especially public
networks.
This patch allows netdev to generate a new MAC address on a
per-network basis. The generated MAC will remain the same when
connecting to the same network. This allows reauthentications
or roaming to work, and not have to fully re-connect (which would
be required if the MAC changed on every connection).
Changing the MAC requires bringing the interface down. This does
lead to potential race conditions with respect to external
processes. There are two potential conditions which are explained
in a TODO comment in this patch.
This API was updated to take an extra boolean which will
automatically power up the device while changing the MAC
address. Since this is what IWD does anyways we can avoid
the need for an intermediate callback and go right into
netdev_initial_up_cb.
mac80211 drivers seem to send the disconnect event which is triggered by
CMD_DISCONNECT prior to the CMD_DISCONNECT response. However, some
drivers, namely brcmfmac, send the response first and then send the
disconnect event. This confused iwd when a connection was immediately
triggered after a disconnection (network switch operation).
Fix this by making sure that connected variable isn't set until the
connect event is actually processed, and ignore disconnect events which
come after CMD_DISCONNECT has alredy succeeded.
