The scan result handling was fragile because it assumed the kernel
would only give results matching the requested SSID. This isn't
something we should assume so instead keep the configuration object
around until after the scan and use the target SSID to lookup the
network.
Nearly every use of the ssid member first has to memcpy it to a
buffer and NULL terminate. Instead just store the ssid as a
string when creating/parsing from JSON.
The DPP-PKEX spec provides a very limited list of frequencies used
to discover configurators, only 3 on 2.4 and 5GHz bands. Since
configurators (at least in IWD's implementation) are only allowed
on the current operating frequency its very unlikely an enrollee
will find a configurator on these frequencies out of the entire
spectrum.
The spec does mention that the 3 default frequencies should be used
"In lieu of specific channel information obtained in a manner outside
the scope of this specification, ...". This allows the implementation
some flexibility in using a broader range of frequencies.
To increase the chances of finding a configurator shared code
enrollees will first issue a scan to determine what access points are
around, then iterate these frequencies. This is especially helpful
when the configurators are IWD-based since we know that they'll be
on the same channels as the APs in the area.
The post-DPP connection was never done quite right due to station's
state being unknown. The state is now tracked in DPP by a previous
patch but the scan path in DPP is still wrong.
It relies on station autoconnect logic which has the potential to
connect to a different network than what was configured with DPP.
Its unlikely but still could happen in theory. In addition the scan
was not selectively filtering results by the SSID that DPP
configured.
This fixes the above problems by first filtering the scan by the
SSID. Then setting the scan results into station without triggering
autoconnect. And finally using network_autoconnect() directly
instead of relying on station to choose the SSID.
DPP (both DPP and PKEX) run the risk of odd behavior if station
decides to change state. DPP is completely unaware of this and
best case would just result in a protocol failure, worst case
duplicate calls to __station_connect_network.
Add a station watch and stop DPP if station changes state during
the protocol.
Commit c59669a366 ("netdev: disambiguate between disconnection types")
introduced different paths for different types of disconnection
notifications from netdev. Formalize this further by having
netdev_connect_failed only invoke connect_cb.
Disconnections that could be triggered outside of connection
related events are now handled on a different code path. For this
purpose, netdev_disconnected() is introduced.
When a roam event is received, iwd generates a firmware scan request and
notifies its event filter of the ROAMING condition. In cases where the
firmware scan could not be started successfully, netdev_connect_failed
is invoked. This is not a correct use of netev_connect_failed since it
doesn't actually disconnect the underlying netdev and the reflected
state becomes de-synchronized from the underlying kernel device.
The firmware scan request could currently fail for two reasons:
1. nl80211 genl socket is in a bad state, or
2. the scan context does not exist
Since both reasons are highly unlikely, simply use L_WARN instead.
The other two cases where netdev_connect_failed is used could only occur
if the kernel message is invalid. The message is ignored in that case
and a warning is printed.
The situation described above also exists in netdev_get_fw_scan_cb. If
the scan could not be completed successfully, there's not much iwd can
do to recover. Have iwd remain in roaming state and print an error.
There are generally three scenarios where iwd generates a disconnection
command to the kernel:
1. Error conditions stemming from a connection related event. For
example if SAE/FT/FILS authentication fails during Authenticate or
Associate steps and the kernel doesn't disconnect properly.
2. Deauthentication after the connection has been established and not
related to a connection attempt in progress. For example, SA Query
processing that triggers an disconnect.
3. Disconnects that are triggered due to a handshake failure or if
setting keys resulting from the handshake fails. These disconnects
can be triggered as a result of a pending connection or when a
connection has been established (e.g. due to rekeying).
Distinguish between 1 and 2/3 by having the disconnect procedure take
different paths. For now there are no functional changes since all
paths end up in netdev_connect_failed(), but this will change in the
future.
While here, also get rid of netdev_del_station. The only user of this
function was in ap.c and it could easily be replaced by invoking the new
nl80211_build_del_station function. The callback used by
netdev_build_del_station only printed an error and didn't do anything
useful. Get rid of it for now.
netdev_begin_connection() already invokes netdev_connect_failed on
error. Remove any calls to netdev_connect_failed in callers of
netdev_begin_connection().
Fixes: 4165d9414f ("netdev: use wiphy radio work queue for connections")
If netdev_get_oci fails, a goto deauth is invoked in order to terminate
the current connection and return an error to the caller. Unfortunately
the deauth label builds CMD_DEAUTHENTICATE in order to terminate the
connection. This was fine because it used to handle authentication
protocols that ran over CMD_AUTHENTICATE and CMD_ASSOCIATE. However,
OCI can also be used on FullMAC hardware that does not support them.
Use CMD_DISCONNECT instead which works everywhere.
Fixes: 06482b8116 ("netdev: Obtain operating channel info")
The reason code field was being obtained as a uint8_t value, while it is
actually a uint16_t in little-endian byte order.
Fixes: f3cc96499c ("netdev: added support for SA Query")
The reason code from deauthentication frame was being obtained as a
uint8_t instead of a uint16_t. The value was only ever used in an
informational statement. Since the value was in little endian, only the
first 8 bits of the reason code were obtained. Fix that.
Fixes: 2bebb4bdc7 ("netdev: Handle deauth frames prior to association")
Several tests do not pass due to some additional changes that have
not been merged. Remove these cases and add some hardening after
discovering some unfortunate wpa_supplicant behavior.
- Disable p2p in wpa_supplicant. With p2p enabled an extra device
is created which starts receiving DPP frames and printing
confusing messages.
- Remove extra asserts which don't make sense currently. These
will be added back later as future additions to PKEX are
upstreamed.
- Work around wpa_supplicant retransmit limitation. This is
described in detail in the comment in pkex_test.py
- wait_for_event was returning a list in certain cases, not the
event itself
- The configurator ID was not being printed (',' instead of '%')
- The DPP ID was not being properly waited for with PKEX
With the addition of DPP PKEX autotests some of the timeouts are
quite long and hit test-runners maximum timeouts. For UML we should
allow this since time-travel lets us skip idle waits. Move the test
timeout out of a global define and into the argument list so QEMU
and UML can define it differently.
The StartConfigurator() call was left out since there would be no
functional difference to the user in iwctl. Its expected that
human users of the shared code API provide the code/id ahead of
time, i.e. use ConfigureEnrollee/StartEnrollee.
Check that enough space for newline and 0-byte is left in line.
This fixes a buffer overflow on specific completion results.
Reported-By: Leona Maroni <dev@leona.is>
Adds a configurator variant to be used along side an agent. When
called the configurator will start and wait for an initial PKEX
exchange message from an enrollee at which point it will request
the code from an agent. This provides more flexibility for
configurators that are capable of configuring multiple enrollees
with different identifiers/codes.
Note that the timing requirements per the DPP spec still apply
so this is not meant to be used with a human configurator but
within an automated agent which does a quick lookup of potential
identifiers/codes and can reply within the 200ms window.
The PKEX configurator role is currently limited to being a responder.
When started the configurator will listen on its current operating
channel for a PKEX exchange request. Once received it and the
encrypted key is properly decrypted it treats this peer as the
enrollee and won't allow configurations from other peers unless
PKEX is restarted. The configurator will encrypt and send its
encrypted ephemeral key in the PKEX exchange response. The enrollee
then sends its encrypted bootstrapping key (as commit-reveal request)
then the same for the configurator (as commit-reveal response).
After this, PKEX authentication begins. The enrollee is expected to
send the authenticate request, since its the initiator.
This is the initial support for PKEX enrollees acting as the
initiator. A PKEX initiator starts the protocol by broadcasting
the PKEX exchange request. This request contains a key encrypted
with the pre-shared PKEX code. If accepted the peer sends back
the exchange response with its own encrypted key. The enrollee
decrypts this and performs some crypto/hashing in order to establish
an ephemeral key used to encrypt its own boostrapping key. The
boostrapping key is encrypted and sent to the peer in the PKEX
commit-reveal request. The peer then does the same thing, encrypting
its own bootstrapping key and sending to the initiator as the
PKEX commit-reveal response.
After this, both peers have exchanged their boostrapping keys
securely and can begin DPP authentication, then configuration.
For now the enrollee will only iterate the default channel list
from the Easy Connect spec. Future upates will need to include some
way of discovering non-default channel configurators, but the
protocol needs to be ironed out first.
Stop() will now return NotFound if DPP is not running. This causes
the DPP test to fail since it calls this regardless if the protocol
already stopped. Ignore this exception since tests end in various
states, some stopped and some not.
PKEX and DPP will share the same state machine since the DPP protocol
follows PKEX. This does pose an issue with the DBus interfaces
because we don't want DPP initiated by the SharedCode interface to
start setting properties on the DeviceProvisioning interface.
To handle this a dpp_interface enum is being introduced which binds
the dpp_sm object to a particular interface, for the life of the
protocol run. Once the protocol finishes the dpp_sm can be unbound
allowing either interface to use it again later.
This mispelling was present in the configuration, so I retained parsing
of the legacy BandModifier*Ghz options for compatibility. Without this
change anyone spelling GHz correctly in their configs would be very
confused.
PKEX is part of the WFA EasyConnect specification and is
an additional boostrapping method (like QR codes) for
exchanging public keys between a configurator and enrollee.
PKEX operates over wifi and requires a key/code be exchanged
prior to the protocol. The key is used to encrypt the exchange
of the boostrapping information, then DPP authentication is
started immediately aftewards.
This can be useful for devices which don't have the ability to
scan a QR code, or even as a more convenient way to share
wireless credentials if the PSK is very secure (i.e. not a
human readable string).
PKEX would be used via the three DBus APIs on a new interface
SharedCodeDeviceProvisioning.
ConfigureEnrollee(a{sv}) will start a configurator with a
static shared code (optionally identifier) passed in as the
argument to this method.
StartEnrollee(a{sv}) will start a PKEX enrollee using a static
shared code (optionally identifier) passed as the argument to
the method.
StartConfigurator(o) will start a PKEX configurator and use the
agent specified by the path argument. The configurator will query
the agent for a specific code when an enrollee sends the initial
exchange message.
After the PKEX protocol is finished, DPP bootstrapping keys have
been exchanged and DPP Authentication will start, followed by
configuration.
Beacon loss handling was removed in the past because it was
determined that this even always resulted in a disconnect. This
was short sighted and not always true. The default kernel behavior
waits for 7 lost beacons before emitting this event, then sends
either a few nullfuncs or probe requests to the BSS to determine
if its really gone. If these come back successfully the connection
will remain alive. This can give IWD some time to roam in some
cases so we should be handling this event.
Since beacon loss indicates a very poor connection the roam scan
is delayed by a few seconds in order to give the kernel a chance
to send the nullfuncs/probes or receive more beacons. This may
result in a disconnect, but it would have happened anyways.
Attempting a roam mainly handles the case when the connection can
be maintained after beacon loss, but is still poor.
This is being done to allow the DPP module to work correctly. DPP
currently uses __station_connect_network incorrectly since it
does not (and cannot) change the state after calling. The only
way to connect with a state change is via station_connect_network
which requires a DBus method that triggered the connection; DPP
does not have this due to its potentially long run time.
To support DPP there are a few options:
1. Pass a state into __station_connect_network (this patch)
2. Support a NULL DBus message in station_connect_network. This
would require several NULL checks and adding all that to only
support DPP just didn't feel right.
3. A 3rd connect API in station which wraps
__station_connect_network and changes the state. And again, an
entirely new API for only DPP felt wrong (I guess we did this
for network_autoconnect though...)
Its about 50/50 between call sites that changed state after calling
and those that do not. Changing the state inside
__station_connect_network felt useful enough to cover the cases that
could benefit and the remaining cases could handle it easily enough:
- network_autoconnect(), and the state is changed by station after
calling so it more or less follows the same pattern just routes
through network. This will now pass the CONNECTING_AUTO state
from within network vs station.
- The disconnect/reconnect path. Here the state is changed to
ROAMING prior in order to avoid multiple state changes. Knowing
this the same ROAMING state can be passed which won't trigger a
state change.
- Retrying after a failed BSS. The state changes on the first call
then remains the same for each connection attempt. To support this
the current station->state is passed to avoid a state change.
Until now IWD only supported enrollees as responders (configurators
could do both). For PKEX it makes sense for the enrollee to be the
initiator because configurators in the area are already on their
operating channel and going off is inefficient. For PKEX, whoever
initiates also initiates authentication so for this reason the
authentication path is being opened up to allow enrollees to
initiate.
The check for the header was incorrect according to the spec.
Table 58 indicates that the "Query Response Info" should be set
to 0x00 for the configuration request. The frame handler was
expecting 0x7f which is the value for the config response frame.
Unfortunately wpa_supplicant also gets this wrong and uses 0x7f
in all cases which is likely why this value was set incorrectly
in IWD. The issue is that IWD's config request is correct which
means IWD<->IWD configuration is broken. (and wpa_supplicant as
a configurator likely doesn't validate the config request).
Fix this by checking both 0x7f and 0x00 to handle both
supplicants.
Stopping periodic scans and not restarting them prevents autoconnect
from working again if DPP (or the post-DPP connect) fails. Since
the DPP offchannel work is at a higher priority than scanning (and
since new offchannels are queue'd before canceling) there is no risk
of a scan happening during DPP so its safe to leave periodic scans
running.
The packet loss handler puts a higher priority on roaming compared
to the low signal roam path. This is generally beneficial since this
event usually indicates some problem with the BSS and generally is
an indicator that a disconnect will follow sometime soon.
But by immediately issuing a scan we run the risk of causing many
successive scans if more packet loss events arrive following
the roam scans (and if no candidates are found). Logs provided
further.
To help with this handle the first event with priority and
immediately issue a roam scan. If another event comes in within a
certain timeframe (2 seconds) don't immediately scan, but instead
rearm the roam timer instead of issuing a scan. This also handles
the case of a low signal roam scan followed by a packet loss
event. Delaying the roam will at least provide some time for packets
to get out in between roam scans.
Logs were snipped to be less verbose, but this cycled happened
5 times prior. In total 7 scans were issued in 5 seconds which may
very well have been the reason for the local disconnect:
Oct 27 16:23:46 src/station.c:station_roam_failed() 9
Oct 27 16:23:46 src/wiphy.c:wiphy_radio_work_done() Work item 29 done
Oct 27 16:23:47 src/netdev.c:netdev_mlme_notify() MLME notification Notify CQM(64)
Oct 27 16:23:47 src/station.c:station_packets_lost() Packets lost event: 10
Oct 27 16:23:47 src/station.c:station_roam_scan() ifindex: 9
Oct 27 16:23:47 src/wiphy.c:wiphy_radio_work_insert() Inserting work item 30
Oct 27 16:23:47 src/wiphy.c:wiphy_radio_work_next() Starting work item 30
Oct 27 16:23:47 src/station.c:station_start_roam() Using cached neighbor report for roam
Oct 27 16:23:47 src/scan.c:scan_notify() Scan notification Trigger Scan(33)
Oct 27 16:23:47 src/scan.c:scan_request_triggered() Active scan triggered for wdev a
Oct 27 16:23:47 src/scan.c:scan_notify() Scan notification New Scan Results(34)
Oct 27 16:23:47 src/netdev.c:netdev_link_notify() event 16 on ifindex 9
... scan results ...
Oct 27 16:23:47 src/station.c:station_roam_failed() 9
Oct 27 16:23:47 src/wiphy.c:wiphy_radio_work_done() Work item 30 done
Oct 27 16:23:47 src/netdev.c:netdev_mlme_notify() MLME notification Notify CQM(64)
Oct 27 16:23:47 src/station.c:station_packets_lost() Packets lost event: 10
Oct 27 16:23:47 src/station.c:station_roam_scan() ifindex: 9
Oct 27 16:23:47 src/wiphy.c:wiphy_radio_work_insert() Inserting work item 31
Oct 27 16:23:47 src/wiphy.c:wiphy_radio_work_next() Starting work item 31
Oct 27 16:23:47 src/station.c:station_start_roam() Using cached neighbor report for roam
Oct 27 16:23:47 src/scan.c:scan_notify() Scan notification Trigger Scan(33)
Oct 27 16:23:47 src/scan.c:scan_request_triggered() Active scan triggered for wdev a
Oct 27 16:23:48 src/scan.c:scan_notify() Scan notification New Scan Results(34)
Oct 27 16:23:48 src/netdev.c:netdev_link_notify() event 16 on ifindex 9
... scan results ...
Oct 27 16:23:48 src/station.c:station_roam_failed() 9
Oct 27 16:23:48 src/wiphy.c:wiphy_radio_work_done() Work item 31 done
Oct 27 16:23:48 src/netdev.c:netdev_mlme_notify() MLME notification Notify CQM(64)
Oct 27 16:23:48 src/station.c:station_packets_lost() Packets lost event: 10
Oct 27 16:23:48 src/station.c:station_roam_scan() ifindex: 9
Oct 27 16:23:48 src/wiphy.c:wiphy_radio_work_insert() Inserting work item 32
Oct 27 16:23:48 src/wiphy.c:wiphy_radio_work_next() Starting work item 32
Oct 27 16:23:48 src/station.c:station_start_roam() Using cached neighbor report for roam
Oct 27 16:23:48 src/scan.c:scan_notify() Scan notification Trigger Scan(33)
Oct 27 16:23:48 src/scan.c:scan_request_triggered() Active scan triggered for wdev a
Oct 27 16:23:49 src/netdev.c:netdev_link_notify() event 16 on ifindex 9
Oct 27 16:23:49 src/netdev.c:netdev_mlme_notify() MLME notification Del Station(20)
Oct 27 16:23:49 src/netdev.c:netdev_mlme_notify() MLME notification Deauthenticate(39)
Oct 27 16:23:49 src/netdev.c:netdev_deauthenticate_event()
Oct 27 16:23:49 src/netdev.c:netdev_mlme_notify() MLME notification Disconnect(48)
Oct 27 16:23:49 src/netdev.c:netdev_disconnect_event()
Oct 27 16:23:49 Received Deauthentication event, reason: 4, from_ap: false
