SAE is meant to work in a peer-to-peer fashion where neither side acts
as a dedicated authenticator or supplicant. This was not the case with
the current code. The handshake state authenticator address was hard
coded as the destination address for all packets, which will not work
when mesh comes into play. This also made unit testing the full SAE
procedure with two sae_sm's impossible.
This patch adds a peer address element to sae_sm which is filled with
either aa/spa based on the value of handshake->authenticator
This removes the authenticator bit in eapol_sm as well as unifies
eapol_register_authenticator and eapol_register. Taking advantage
of the handshake state authenticator bit we no longer have a need
for 2 separate register functions.
ap, and adhoc were also updated to set the authenticator bit in
the handshake and only use eapol_register to register their sm's.
netdev was updated to use the authenticator bit when choosing the
correct key address for adhoc.
Both SAE and adhoc can benefit from knowing whether the handshake state
is an authenticator or a supplicant. It will allow both to easily
obtain the remote address rather than sorting out if aa/spa match the
devices own address.
The send confirm counter is incremented before calling sae_send_confirm
in all cases, but the function itself was also incrementing sc after
sending the packet. This isn't critical to the successful execution of
SAE as the AP just uses the sc value in the packet but it did violate
the 802.11 spec.
In order to plug SAE into the existing connect mechanism the actual
CMD_CONNECT message is never sent, rather sae_register takes care
of sending out CMD_AUTHENTICATE. This required some shuffling of
code in order to handle both eapol and sae. In the case of non-SAE
authentication everything behaves as it did before. When using SAE
an sae_sm is created when a connection is attempted but the eapol_sm
is not. After SAE succeeds it will start association and then create
the eapol_sm and start the 4-way handshake.
This change also adds the handshake SAE events to device and
initializes SAE in main.
SAE (Simultaneous Authentication of Equals) takes place during
authentication, and followed by EAPoL/4-way handshake. This
module handles the entire SAE commit/confirm exchange. This was
done similar to eapol.
SAE begins when sae_register is called. At this point a commit
message will be created and sent out which kicks off the SAE
authentication procedure.
The commit/confirm exchange is very similar to EAP-PWD, so all
the ecc utility functions could be re-used as-is. A few new ecc
utility functions were added to conform to the 80211 'blinding'
technique for computing the password element.
For an SAE network, the raw passphrase is required. For this reason,
known network psk files should now always contain a 'Passphrase' entry.
If a psk file is found without a Passphrase entry the agent will be asked
for the Passphrase before connecting. This will update the legacy psk
file with the Passphrase entry.
Some compilers complained that:
../unit/test-ecc.c: In function ‘run_test’:
../unit/test-ecc.c:295:38: warning: ‘lres’ may be used uninitialized in
this function [-Wmaybe-uninitialized]
assert(data->lres == lres);
^
Due to the quirk in how storage_network_sync implements file writing,
iwd was generating unnecessary KnownNetwork removal events (and
preventing certain test cases from passing successfully)
storage_network_sync tries to perform atomic writes by writing to a
temporary storage location first, unlinking the existing file and
renaming the tmp file as the original.
This generates a set of inotify events which confuses the current
implementation.
The previous change did not consider the case of the PSK being written
for the very first time. In this case storage_network_open would return
NULL and an empty file would be written.
Change this so that if storage_network_open fails, then the current
network settings are written to disk and not a temporary.
Reload the network settings from disk before calling
storage_network_sync in network_sync_psk to avoid potentially
overwriting changes made to the storage by user since the connection
attempt started. This won't account for all situations but it
covers some of them and doesn't cost us much.
The default behavior of NetworkObject.connect() is to wait for the
Connect dbus method to reply before returning back to the test. This
change makes it possible to connect, but not wait for a reply and
continue on with the test (by specifying wait=False). This is
specifically required to test SAE anti-clogging, where the AP needs
to have several simultaneous connections at once for the anti-clogging
logic to trigger. This change also adds Device.wait_for_connected()
which waits for the device interface State variable to be "connected".
Our logic would set CONTROL_PORT_OVER_NL80211 even in cases where
CONTROL_PORT wasn't used (e.g. for open networks). While the kernel
ignored this attribute in this case, it is nicer to set this only if
CONTROL_PORT is intended to be used.
SAE will require some of the same CMD_ASSOCIATE building code that
FT currently uses. This breaks out the common code from FT into
netdev_build_cmd_associate_common.
This also required passing in the akm suite in case the key description
version was zero. In the zero case the akm must be checked. For now this
only supports the SAE akm.
Update the known networks list and network properties on file creations,
removals and modifications. We watch for these filesystem events using
ell's fswatch and react accordingly.
This makes testEAP-PEAP-GTC pass for me by re-adding the check for the
GTC-Secret setting which was replaced with the check for the secrets
list in 3d2285ec7e.
eap_append_secret now takes a new cache_policy parameter which can be
used by the EAP method to signal that the value received from the agent
is to never be cached, i.e. each value can only be used once. The
parameter value should be EAP_CACHE_NEVER for this and we use this in
value EAP-GTC where the secret tokens are one time use. The
EAP_CACHE_TEMPORARY value is used in other methods, it preserves the
default behaviour where a secret can be cached for as long as the
network stays in range (this is the current implementation more than a
design choice I believe, I didn't go for a more specific enum name as
this may still change I suppose).
SAE generates the PMKID during the authentication process, rather than
generating it on-the-fly using the PMK. For this reason SAE needs to be
able to set the PMKID once its generated. A new flag was also added
(has_pmkid) which signifies if the PMKID was set or if it should be
generated.
SAE needs access to the raw passphrase, not the PSK which network
saves. This changes saves the passphrase in network and handshake
objects, as well as adds getters to both objects so SAE can retrieve
the passphrase.
