[PATCH v3 0/9] DPP PKEX Changes

[PATCH v3 0/9] DPP PKEX Changes

[James Prestwood]

v3:
 * Corrected the config header check patch

 * Kept the scan/connect logic in DPP but instead changed
   __station_connect_network to be more flexible to this
   use case. I don't think there was many great ways to
   do this, I'm open to suggestions on alternatives.

   Also, I didn't forget about the need to filter the by
   SSID in the DPP scan path, I just left that out for now
   until the station <-> DPP interaction is nailed down. In
   addition to your comments I relalized that the scan notify
   callback should call __station_connect_network (or
   whatever) rather than enabling autoconnect. I'll send
   follow-up patches for this.

 * Documented SharedCodeAgent interface

 * Better documented the DPP SharedCode interface methods

James Prestwood (9):
  dpp: remove scan_periodic_stop calls
  dpp: fix config request header check
  dpp: allow enrollee to be authentication initiator
  dbus: add net.connman.iwd.SharedCodeAgent DBus interface
  station: provide new state in __station_connect_network
  doc: PKEX support for DPP
  dpp: SharedCode interface, {Register,Unregister}SharedCodeAgent
  dpp: initial version of PKEX enrollee support
  dpp: initial version of PKEX configurator support

 doc/device-provisioning-api.txt |  149 +++
 src/dbus.h                      |    1 +
 src/dpp.c                       | 1681 +++++++++++++++++++++++++++++--
 src/network.c                   |    3 +-
 src/station.c                   |   23 +-
 src/station.h                   |    2 +-
 6 files changed, 1754 insertions(+), 105 deletions(-)

-- 
2.25.1

[PATCH v3 1/9] dpp: remove scan_periodic_stop calls

[James Prestwood]

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.
---
 src/dpp.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/src/dpp.c b/src/dpp.c
index 638d65e0..cfdfaa38 100644
--- a/src/dpp.c
+++ b/src/dpp.c
@@ -2553,8 +2553,6 @@ static struct l_dbus_message *dpp_dbus_start_enrollee(struct l_dbus *dbus,
 	 */
 	dpp_start_presence(dpp, &freq, 1);
 
-	scan_periodic_stop(dpp->wdev_id);
-
 	dpp_property_changed_notify(dpp);
 
 	return NULL;
@@ -2685,8 +2683,6 @@ static struct l_dbus_message *dpp_start_configurator_common(
 						network_get_ssid(network),
 						hs->akm_suite);
 
-	scan_periodic_stop(dpp->wdev_id);
-
 	dpp_property_changed_notify(dpp);
 
 	l_debug("DPP Start Configurator: %s", dpp->uri);
-- 
2.25.1

[PATCH v3 2/9] dpp: fix config request header check

[James Prestwood]

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.
---
 src/dpp.c | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/src/dpp.c b/src/dpp.c
index cfdfaa38..dcf5953f 100644
--- a/src/dpp.c
+++ b/src/dpp.c
@@ -920,6 +920,21 @@ static void dpp_send_config_response(struct dpp_sm *dpp, uint8_t status)
 	dpp_send_frame(dpp, iov, 2, dpp->current_freq);
 }
 
+static bool dpp_check_config_header(const uint8_t *ptr)
+{
+	/*
+	 * Table 58. General Format of DPP Configuration Request frame
+	 *
+	 * Unfortunately wpa_supplicant hard codes 0x7f as the Query Response
+	 * Info so we need to handle both cases.
+	 */
+	return ptr[0] == IE_TYPE_ADVERTISEMENT_PROTOCOL &&
+			ptr[1] == 0x08 &&
+			(ptr[2] == 0x7f || ptr[2] == 0x00) &&
+			ptr[3] == IE_TYPE_VENDOR_SPECIFIC &&
+			ptr[4] == 5;
+}
+
 static void dpp_handle_config_request_frame(const struct mmpdu_header *frame,
 				const void *body, size_t body_len,
 				int rssi, void *user_data)
@@ -937,8 +952,6 @@ static void dpp_handle_config_request_frame(const struct mmpdu_header *frame,
 	const uint8_t *e_nonce = NULL;
 	size_t wrapped_len = 0;
 	_auto_(l_free) uint8_t *unwrapped = NULL;
-	uint8_t hdr_check[] = { IE_TYPE_ADVERTISEMENT_PROTOCOL, 0x08, 0x7f,
-				IE_TYPE_VENDOR_SPECIFIC, 5 };
 	struct json_iter jsiter;
 	_auto_(l_free) char *tech = NULL;
 	_auto_(l_free) char *role = NULL;
@@ -965,10 +978,10 @@ static void dpp_handle_config_request_frame(const struct mmpdu_header *frame,
 
 	dpp->diag_token = *ptr++;
 
-	if (memcmp(ptr, hdr_check, sizeof(hdr_check)))
+	if (!dpp_check_config_header(ptr))
 		return;
 
-	ptr += sizeof(hdr_check);
+	ptr += 5;
 
 	if (memcmp(ptr, wifi_alliance_oui, sizeof(wifi_alliance_oui)))
 		return;
-- 
2.25.1

[PATCH v3 3/9] dpp: allow enrollee to be authentication initiator

[James Prestwood]

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.
---
 src/dpp.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/dpp.c b/src/dpp.c
index dcf5953f..e5e1b3fa 100644
--- a/src/dpp.c
+++ b/src/dpp.c
@@ -1468,7 +1468,7 @@ static bool dpp_send_authenticate_request(struct dpp_sm *dpp)
 	struct scan_bss *bss = station_get_connected_bss(station);
 
 	/* Got disconnected by the time the peer was discovered */
-	if (!bss) {
+	if (dpp->role == DPP_CAPABILITY_CONFIGURATOR && !bss) {
 		dpp_reset(dpp);
 		return false;
 	}
@@ -1489,7 +1489,8 @@ static bool dpp_send_authenticate_request(struct dpp_sm *dpp)
 				i_proto_key, dpp->key_len * 2);
 	ptr += dpp_append_attr(ptr, DPP_ATTR_PROTOCOL_VERSION, &version, 1);
 
-	if (dpp->current_freq != bss->frequency) {
+	if (dpp->role == DPP_CAPABILITY_CONFIGURATOR &&
+					dpp->current_freq != bss->frequency) {
 		uint8_t pair[2] = { 81,
 				band_freq_to_channel(bss->frequency, NULL) };
 
@@ -1926,9 +1927,6 @@ static void authenticate_response(struct dpp_sm *dpp, const uint8_t *from,
 	if (dpp->state != DPP_STATE_AUTHENTICATING)
 		return;
 
-	if (dpp->role != DPP_CAPABILITY_CONFIGURATOR)
-		return;
-
 	if (!dpp->freqs)
 		return;
 
@@ -2082,6 +2080,10 @@ static void authenticate_response(struct dpp_sm *dpp, const uint8_t *from,
 	dpp->current_freq = dpp->new_freq;
 
 	dpp_send_authenticate_confirm(dpp);
+
+	if (dpp->role == DPP_CAPABILITY_ENROLLEE)
+		dpp_configuration_start(dpp, from);
+
 }
 
 static void dpp_handle_presence_announcement(struct dpp_sm *dpp,
-- 
2.25.1

[PATCH v3 4/9] dbus: add net.connman.iwd.SharedCodeAgent DBus interface

[James Prestwood]

---
 src/dbus.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/dbus.h b/src/dbus.h
index cff64ae2..b43412d7 100644
--- a/src/dbus.h
+++ b/src/dbus.h
@@ -47,6 +47,7 @@
 #define IWD_DPP_PKEX_INTERFACE "net.connman.iwd.SharedCodeDeviceProvisioning"
 #define IWD_NETCONFIG_AGENT_INTERFACE \
 	"net.connman.iwd.NetworkConfigurationAgent"
+#define IWD_SHARED_CODE_AGENT_INTERFACE "net.connman.iwd.SharedCodeAgent"
 
 #define IWD_BASE_PATH "/net/connman/iwd"
 #define IWD_AGENT_MANAGER_PATH IWD_BASE_PATH
-- 
2.25.1

[PATCH v3 5/9] station: provide new state in __station_connect_network

[James Prestwood]

This is being done to allow the DPP module to work correctl. 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.
---
 src/dpp.c     |  3 ++-
 src/network.c |  3 ++-
 src/station.c | 23 +++++++++++------------
 src/station.h |  2 +-
 4 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/src/dpp.c b/src/dpp.c
index e5e1b3fa..b0a79361 100644
--- a/src/dpp.c
+++ b/src/dpp.c
@@ -833,7 +833,8 @@ static void dpp_handle_config_response_frame(const struct mmpdu_header *frame,
 	offchannel_cancel(dpp->wdev_id, dpp->offchannel_id);
 
 	if (network && bss)
-		__station_connect_network(station, network, bss);
+		__station_connect_network(station, network, bss,
+						STATION_STATE_CONNECTING);
 	else if (station) {
 		dpp->connect_scan_id = scan_active(dpp->wdev_id, NULL, 0,
 						dpp_scan_triggered,
diff --git a/src/network.c b/src/network.c
index 3099d102..f203834c 100644
--- a/src/network.c
+++ b/src/network.c
@@ -991,7 +991,8 @@ int network_autoconnect(struct network *network, struct scan_bss *bss)
 		return -ENOTSUP;
 	}
 
-	return __station_connect_network(station, network, bss);
+	return __station_connect_network(station, network, bss,
+						STATION_STATE_CONNECTING_AUTO);
 
 close_settings:
 	network_settings_close(network);
diff --git a/src/station.c b/src/station.c
index d4eb0cd8..3da02b06 100644
--- a/src/station.c
+++ b/src/station.c
@@ -280,9 +280,6 @@ static int station_autoconnect_next(struct station *station)
 
 		r = network_autoconnect(network, bss);
 		if (!r) {
-			station_enter_state(station,
-						STATION_STATE_CONNECTING_AUTO);
-
 			if (station->quick_scan_id) {
 				scan_cancel(netdev_get_wdev_id(station->netdev),
 						station->quick_scan_id);
@@ -3084,7 +3081,7 @@ static bool station_try_next_bss(struct station *station)
 		return false;
 
 	ret = __station_connect_network(station, station->connected_network,
-						next);
+						next, station->state);
 	if (ret < 0)
 		return false;
 
@@ -3421,7 +3418,7 @@ static void station_netdev_event(struct netdev *netdev, enum netdev_event event,
 }
 
 int __station_connect_network(struct station *station, struct network *network,
-				struct scan_bss *bss)
+				struct scan_bss *bss, enum station_state state)
 {
 	struct handshake_state *hs;
 	int r;
@@ -3448,6 +3445,9 @@ int __station_connect_network(struct station *station, struct network *network,
 	station->connected_bss = bss;
 	station->connected_network = network;
 
+	if (station->state != state)
+		station_enter_state(station, state);
+
 	return 0;
 }
 
@@ -3461,7 +3461,8 @@ static void station_disconnect_onconnect_cb(struct netdev *netdev, bool success,
 
 	err = __station_connect_network(station,
 					station->connect_pending_network,
-					station->connect_pending_bss);
+					station->connect_pending_bss,
+					STATION_STATE_CONNECTING);
 
 	station->connect_pending_network = NULL;
 	station->connect_pending_bss = NULL;
@@ -3472,8 +3473,6 @@ static void station_disconnect_onconnect_cb(struct netdev *netdev, bool success,
 						station->connect_pending));
 		return;
 	}
-
-	station_enter_state(station, STATION_STATE_CONNECTING);
 }
 
 static void station_disconnect_onconnect(struct station *station,
@@ -3531,12 +3530,11 @@ void station_connect_network(struct station *station, struct network *network,
 		return;
 	}
 
-	err = __station_connect_network(station, network, bss);
+	err = __station_connect_network(station, network, bss,
+					STATION_STATE_CONNECTING);
 	if (err < 0)
 		goto error;
 
-	station_enter_state(station, STATION_STATE_CONNECTING);
-
 	station->connect_pending = l_dbus_message_ref(message);
 
 	station_set_autoconnect(station, true);
@@ -3746,7 +3744,8 @@ static void station_disconnect_reconnect_cb(struct netdev *netdev, bool success,
 	struct station *station = user_data;
 
 	if (__station_connect_network(station, station->connected_network,
-					station->connected_bss) < 0)
+					station->connected_bss,
+					STATION_STATE_ROAMING) < 0)
 		station_disassociated(station);
 }
 
diff --git a/src/station.h b/src/station.h
index 24fab321..0d502a08 100644
--- a/src/station.h
+++ b/src/station.h
@@ -89,7 +89,7 @@ void station_remove_event_watch(uint32_t id);
 bool station_set_autoconnect(struct station *station, bool autoconnect);
 
 int __station_connect_network(struct station *station, struct network *network,
-				struct scan_bss *bss);
+				struct scan_bss *bss, enum station_state state);
 void station_connect_network(struct station *station, struct network *network,
 				struct scan_bss *bss,
 				struct l_dbus_message *message);
-- 
2.25.1

[PATCH v3 6/9] doc: PKEX support for DPP

[James Prestwood]

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() will start a PKEX configurator (should be
already registered) which will query an agent for an enrollees
shared code. Enrollees are distinguished by the identifier.

After the PKEX protocol is finished, DPP bootstrapping keys have
been exchanged and DPP Authentication will start, followed by
configuration.
---
 doc/device-provisioning-api.txt | 149 ++++++++++++++++++++++++++++++++
 1 file changed, 149 insertions(+)

diff --git a/doc/device-provisioning-api.txt b/doc/device-provisioning-api.txt
index ac204f46..3c6fc74e 100644
--- a/doc/device-provisioning-api.txt
+++ b/doc/device-provisioning-api.txt
@@ -71,3 +71,152 @@ Properties	boolean Started [readonly]
 
 			Indicates the DPP URI. This property is only available
 			when Started is true.
+
+
+Interface	net.connman.iwd.SharedCodeDeviceProvisioning [Experimental]
+Object path	/net/connman/iwd/{phy0,phy1,...}/{1,2,...}
+
+		ConfigureEnrollee(a{sv})
+
+			Starts a DPP configurator using a shared code (and
+			optionally identifier) set in the dictionary argument.
+			Valid dictionary keys are:
+
+			string Code
+				The shared code to use. The code used by both
+				parties (configurator and enrollee) must match.
+
+			string Identifier
+				An optional identifier. The identifier used by
+				both parties must match. Per the DPP spec the
+				identifier "shall be a UTF-8 string not greater
+				than eighty (80) octets"
+
+			As with the DeviceProvisioning interface, configurators
+			must be connected to the network they wish to configure
+			in order to start.
+
+			Once started a configurator (acting as a responder) will
+			listen on the currently connected channel for an
+			enrollee's initial exchange request which will kick off
+			the shared code bootstrapping protocol (PKEX). Once
+			completed DPP will start automatically. Only one
+			enrollee can be configured per call to
+			ConfigureEnrollee, i.e. once PKEX/DPP is has finished
+			(including failure) the configurator will stop.
+
+			The SharedCode methods have an eventual timeout and will
+			stop automatically after 2 minutes.
+
+			Possible errors:	net.connman.iwd.Busy
+						net.connman.iwd.NotConnected
+						net.connman.InvalidArguments
+
+		StartEnrollee(a{sv})
+
+			Starts a DPP enrollee using a shared code (and
+			optionally identifier) set in the dictionary argument
+			(described above in ConfigureEnrollee).
+
+			As with the device provisioning interface, enrollees
+			must be disconnected in order to start.
+
+			Once started an enrollee (acting as an initiator) will
+			iterate channels sending out broadcast exchange requests
+			waiting for a response from a configurator. A response
+			will kick off the shared code bootstrapping protocol
+			(PKEX), followed by DPP if successful. Once the
+			protocols have completed, or failed, the enrollee will
+			stop. If failed, StartEnrollee will need to be called
+			again to retry.
+
+			Possible errors:	net.connman.iwd.Busy
+						net.connman.iwd.InvalidArguments
+
+		StartConfigurator()
+
+			Start a shared code configurator using an agent to
+			obtain the shared code. This method is meant for an
+			automated use case where a configurator is capable of
+			configuring multiple enrollees, and distinguishing
+			between them by their identifier.
+
+			Prior to calling, a SharedCodeAgent must be registered
+			using RegisterSharedCodeAgent. Only a single agent can
+			be registered per SharedCodeInterface.
+
+			This method behaves nearly the same as ConfigureEnrollee
+			except upon receiving an enrollees first exchange
+			request the registered agent will be asked for the
+			shared code using the RequestSharedCode method.
+
+			Though the agent can provide shared codes for multiple
+			enrollees, this method will only configure a single
+			enrollee at a time. Once completed it will need to be
+			called again to configure additional enrollees.
+
+			Possible errors:	net.connman.iwd.Busy
+						net.connman.iwd.NotConnected
+						net.connman.iwd.NoAgent
+
+		void RegisterSharedCodeAgent(object path)
+
+			Register the agent object for servicing shared code
+			requests on the net.connman.iwd.SharedCodeAgent
+			interface. There may only be one agent registered at a
+			time per SharedCodeDeviceProvisioning interface.
+
+			Possible Errors:	[service].Error.InvalidArguments
+						[service].Error.AlreadyExists
+
+		void UnregisterSharedCodeAgent()
+
+			Unregister an existing agent.
+
+			Possible Errors:	[service].Error.NotFound
+
+Properties	boolean Started [readonly]
+
+			True if shared code device provisioning is currently
+			active. (configurator or enrollee is started)
+
+		string Role [readonly, optional]
+
+			Indicates the DPP role. Possible values are "enrollee"
+			or "configurator". This property is only available when
+			Started is true.
+
+SharedCodeAgent hierarchy
+=========================
+
+Service		unique name
+Interface	net.connman.iwd.SharedCodeAgent [Experimental]
+Object path	freely definable
+
+Methods		void Release() [noreply]
+
+			This method gets called when the service daemon
+			unregisters the agent.
+
+		string RequestSharedCode(object network, string identifier)
+
+			This method gets called when a shared code is requested
+			for a particular enrollee, distingushed by the
+			identifier. The shared code agent should lookup the
+			identifier and return the shared code, or return an
+			error if not found.
+
+			Possible Errors:	[service].Error.Canceled
+						[service].Error.NotFound
+
+		void Cancel(string reason) [noreply]
+
+			This method gets called to indicate that the agent
+			request failed before a reply was returned. The
+			argument will indicate why the request is being
+			cancelled and may be "user-canceled", "timed-out" or
+			"shutdown".
+
+Examples	Requesting a shared code for an enrollee identified by "foo"
+
+			RequestSharedCode("foo") ==> "super_secret_code"
-- 
2.25.1

[PATCH v3 7/9] dpp: SharedCode interface, {Register,Unregister}SharedCodeAgent

[James Prestwood]

This adds the SharedCodeDeviceProvisioning interface as well as
the two agent methods. After the PKEX configurator role is added
it will need this to request a shared code from a registered agent.
---
 src/dpp.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)

diff --git a/src/dpp.c b/src/dpp.c
index b0a79361..57024a26 100644
--- a/src/dpp.c
+++ b/src/dpp.c
@@ -79,6 +79,13 @@ enum dpp_capability {
 	DPP_CAPABILITY_CONFIGURATOR = 0x02,
 };
 
+struct pkex_agent {
+	char *owner;
+	char *path;
+	unsigned int disconnect_watch;
+	uint32_t pending_id;
+};
+
 struct dpp_sm {
 	struct netdev *netdev;
 	char *uri;
@@ -101,6 +108,8 @@ struct dpp_sm {
 
 	enum dpp_state state;
 
+	struct pkex_agent *agent;
+
 	/*
 	 * List of frequencies to jump between. The presence of this list is
 	 * also used to signify that a configurator is an initiator vs responder
@@ -335,6 +344,16 @@ static void dpp_reset(struct dpp_sm *dpp)
 	dpp_property_changed_notify(dpp);
 }
 
+static void pkex_agent_free(void *data)
+{
+	struct pkex_agent *agent = data;
+
+	l_free(agent->owner);
+	l_free(agent->path);
+	l_dbus_remove_watch(dbus_get_bus(), agent->disconnect_watch);
+	l_free(agent);
+}
+
 static void dpp_free(struct dpp_sm *dpp)
 {
 	dpp_reset(dpp);
@@ -354,6 +373,11 @@ static void dpp_free(struct dpp_sm *dpp)
 		dpp->boot_private = NULL;
 	}
 
+	if (dpp->agent) {
+		pkex_agent_free(dpp->agent);
+		dpp->agent = NULL;
+	}
+
 	l_free(dpp);
 }
 
@@ -2753,6 +2777,79 @@ static void dpp_setup_interface(struct l_dbus_interface *interface)
 	l_dbus_interface_property(interface, "URI", 0, "s", dpp_get_uri, NULL);
 }
 
+static void pkex_agent_disconnect(struct l_dbus *dbus, void *user_data)
+{
+	struct dpp_sm *dpp = user_data;
+
+	l_debug("SharedCodeAgent %s disconnected", dpp->agent->path);
+
+	if (dpp->agent->pending_id)
+		l_dbus_cancel(dbus_get_bus(), dpp->agent->pending_id);
+
+	pkex_agent_free(dpp->agent);
+	dpp->agent = NULL;
+}
+
+static struct l_dbus_message *dpp_dbus_pkex_register_agent(
+						struct l_dbus *dbus,
+						struct l_dbus_message *message,
+						void *user_data)
+{
+	struct dpp_sm *dpp = user_data;
+	const char *sender = l_dbus_message_get_sender(message);
+	const char *path;
+
+	if (dpp->agent)
+		return dbus_error_already_exists(message);
+
+	if (!l_dbus_message_get_arguments(message, "o", &path))
+		return dbus_error_invalid_args(message);
+
+	dpp->agent = l_new(struct pkex_agent, 1);
+	dpp->agent->owner = l_strdup(sender);
+	dpp->agent->path = l_strdup(path);
+	dpp->agent->disconnect_watch = l_dbus_add_disconnect_watch(dbus, sender,
+							pkex_agent_disconnect,
+							dpp, NULL);
+
+	l_debug("%s registered a SharedCodeAgent on path %s", sender, path);
+
+	return l_dbus_message_new_method_return(message);
+}
+
+static struct l_dbus_message *dpp_dbus_pkex_unregister_agent(
+						struct l_dbus *dbus,
+						struct l_dbus_message *message,
+						void *user_data)
+{
+	struct dpp_sm *dpp = user_data;
+
+	if (!dpp->agent)
+		return dbus_error_not_found(message);
+
+	if (strcmp(dpp->agent->owner, l_dbus_message_get_sender(message)))
+		return dbus_error_not_found(message);
+
+	l_debug("%s unregistered SharedCodeAgent on path %s", dpp->agent->owner,
+			dpp->agent->path);
+
+	if (dpp->agent->pending_id)
+		l_dbus_cancel(dbus_get_bus(), dpp->agent->pending_id);
+
+	pkex_agent_free(dpp->agent);
+	dpp->agent = NULL;
+
+	return l_dbus_message_new_method_return(message);
+}
+
+static void dpp_setup_pkex_interface(struct l_dbus_interface *interface)
+{
+	l_dbus_interface_method(interface, "RegisterSharedCodeAgent", 0,
+			dpp_dbus_pkex_register_agent, "", "o", "path");
+	l_dbus_interface_method(interface, "UnregisterSharedCodeAgent", 0,
+			dpp_dbus_pkex_unregister_agent, "", "");
+}
+
 static void dpp_destroy_interface(void *user_data)
 {
 	struct dpp_sm *dpp = user_data;
@@ -2775,6 +2872,9 @@ static int dpp_init(void)
 	l_dbus_register_interface(dbus_get_bus(), IWD_DPP_INTERFACE,
 					dpp_setup_interface,
 					dpp_destroy_interface, false);
+	l_dbus_register_interface(dbus_get_bus(), IWD_DPP_PKEX_INTERFACE,
+					dpp_setup_pkex_interface,
+					NULL, false);
 
 	mlme_watch = l_genl_family_register(nl80211, "mlme", dpp_mlme_notify,
 						NULL, NULL);
-- 
2.25.1

[PATCH v3 8/9] dpp: initial version of PKEX enrollee support

[James Prestwood]

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.
---
 src/dpp.c | 765 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 761 insertions(+), 4 deletions(-)

diff --git a/src/dpp.c b/src/dpp.c
index 57024a26..8b47be5c 100644
--- a/src/dpp.c
+++ b/src/dpp.c
@@ -53,10 +53,12 @@
 #include "src/network.h"
 #include "src/handshake.h"
 #include "src/nl80211util.h"
+#include "src/agent.h"
 
 #define DPP_FRAME_MAX_RETRIES 5
 #define DPP_FRAME_RETRY_TIMEOUT 1
 #define DPP_AUTH_PROTO_TIMEOUT 10
+#define DPP_PKEX_PROTO_TIMEOUT 120
 
 static uint32_t netdev_watch;
 static struct l_genl_family *nl80211;
@@ -70,6 +72,8 @@ static uint8_t dpp_prefix[] = { 0x04, 0x09, 0x50, 0x6f, 0x9a, 0x1a, 0x01 };
 enum dpp_state {
 	DPP_STATE_NOTHING,
 	DPP_STATE_PRESENCE,
+	DPP_STATE_PKEX_EXCHANGE,
+	DPP_STATE_PKEX_COMMIT_REVEAL,
 	DPP_STATE_AUTHENTICATING,
 	DPP_STATE_CONFIGURING,
 };
@@ -156,19 +160,66 @@ struct dpp_sm {
 
 	struct l_dbus_message *pending;
 
+	/* PKEX-specific values */
+	char *pkex_id;
+	char *pkex_key;
+	uint8_t pkex_version;
+	struct l_ecc_point *pkex_m;
+	/* Ephemeral key Y' or X' for enrollee or configurator */
+	struct l_ecc_point *y_or_x;
+	/* Ephemeral key pair y/Y or x/X */
+	struct l_ecc_point *pkex_public;
+	struct l_ecc_scalar *pkex_private;
+	uint8_t z[L_ECC_SCALAR_MAX_BYTES];
+	size_t z_len;
+	uint8_t u[L_ECC_SCALAR_MAX_BYTES];
+	size_t u_len;
+
 	bool mcast_support : 1;
 	bool roc_started : 1;
 	bool channel_switch : 1;
 	bool mutual_auth : 1;
 };
 
+static bool dpp_pkex_get_started(struct l_dbus *dbus,
+				struct l_dbus_message *message,
+				struct l_dbus_message_builder *builder,
+				void *user_data)
+{
+	struct dpp_sm *dpp = user_data;
+	bool started = false;
+
+	switch (dpp->state) {
+	case DPP_STATE_PKEX_EXCHANGE:
+	case DPP_STATE_PKEX_COMMIT_REVEAL:
+		started = true;
+		break;
+	default:
+		break;
+	}
+
+	l_dbus_message_builder_append_basic(builder, 'b', &started);
+
+	return true;
+}
+
 static bool dpp_get_started(struct l_dbus *dbus,
 				struct l_dbus_message *message,
 				struct l_dbus_message_builder *builder,
 				void *user_data)
 {
 	struct dpp_sm *dpp = user_data;
-	bool started = (dpp->state != DPP_STATE_NOTHING);
+	bool started = false;
+
+	switch (dpp->state) {
+	case DPP_STATE_PRESENCE:
+	case DPP_STATE_AUTHENTICATING:
+	case DPP_STATE_CONFIGURING:
+		started = true;
+		break;
+	default:
+		break;
+	}
 
 	l_dbus_message_builder_append_basic(builder, 'b', &started);
 
@@ -208,7 +259,9 @@ static bool dpp_get_uri(struct l_dbus *dbus,
 {
 	struct dpp_sm *dpp = user_data;
 
-	if (dpp->state == DPP_STATE_NOTHING)
+	if (dpp->state == DPP_STATE_NOTHING ||
+			dpp->state == DPP_STATE_PKEX_EXCHANGE ||
+			dpp->state == DPP_STATE_PKEX_COMMIT_REVEAL)
 		return false;
 
 	l_dbus_message_builder_append_basic(builder, 's', dpp->uri);
@@ -227,6 +280,16 @@ static void dpp_property_changed_notify(struct dpp_sm *dpp)
 				"URI");
 }
 
+static void dpp_pkex_property_changed_notify(struct dpp_sm *dpp)
+{
+	const char *path = netdev_get_path(dpp->netdev);
+
+	l_dbus_property_changed(dbus_get_bus(), path, IWD_DPP_PKEX_INTERFACE,
+				"Started");
+	l_dbus_property_changed(dbus_get_bus(), path, IWD_DPP_PKEX_INTERFACE,
+				"Role");
+}
+
 static void *dpp_serialize_iovec(struct iovec *iov, size_t iov_len,
 				size_t *out_len)
 {
@@ -277,6 +340,27 @@ static void dpp_free_auth_data(struct dpp_sm *dpp)
 		l_ecc_scalar_free(dpp->m);
 		dpp->m = NULL;
 	}
+
+	if (dpp->pkex_m) {
+		l_ecc_point_free(dpp->pkex_m);
+		dpp->pkex_m = NULL;
+	}
+
+	if (dpp->y_or_x) {
+		l_ecc_point_free(dpp->y_or_x);
+		dpp->y_or_x = NULL;
+	}
+
+	if (dpp->pkex_public) {
+		l_ecc_point_free(dpp->pkex_public);
+		dpp->pkex_public = NULL;
+	}
+
+	if (dpp->pkex_private) {
+		l_ecc_scalar_free(dpp->pkex_private);
+		dpp->pkex_private = NULL;
+	}
+
 }
 
 static void dpp_reset(struct dpp_sm *dpp)
@@ -338,10 +422,24 @@ static void dpp_reset(struct dpp_sm *dpp)
 	explicit_bzero(dpp->k1, dpp->key_len);
 	explicit_bzero(dpp->k2, dpp->key_len);
 	explicit_bzero(dpp->auth_tag, dpp->key_len);
+	explicit_bzero(dpp->z, dpp->key_len);
+	explicit_bzero(dpp->u, dpp->u_len);
+
+	if (dpp->pkex_key) {
+		explicit_bzero(dpp->pkex_key, strlen(dpp->pkex_key));
+		l_free(dpp->pkex_key);
+		dpp->pkex_key = NULL;
+	}
+
+	if (dpp->pkex_id) {
+		l_free(dpp->pkex_id);
+		dpp->pkex_id = NULL;
+	}
 
 	dpp_free_auth_data(dpp);
 
 	dpp_property_changed_notify(dpp);
+	dpp_pkex_property_changed_notify(dpp);
 }
 
 static void pkex_agent_free(void *data)
@@ -381,6 +479,23 @@ static void dpp_free(struct dpp_sm *dpp)
 	l_free(dpp);
 }
 
+static bool dpp_check_pkex_identifier(const char *id)
+{
+	const char *end;
+
+	if (!id)
+		return true;
+
+	/*
+	 * "If an optional code identifier is used, it shall be a UTF-8 string
+	 *  not greater than eighty (80) octets"
+	 */
+	if (!l_utf8_validate(id, strlen(id), &end) || end - id > 80)
+		return false;
+
+	return true;
+}
+
 static void dpp_send_frame_cb(struct l_genl_msg *msg, void *user_data)
 {
 	struct dpp_sm *dpp = user_data;
@@ -1536,6 +1651,71 @@ static bool dpp_send_authenticate_request(struct dpp_sm *dpp)
 	return true;
 }
 
+static void dpp_send_pkex_exchange_request(struct dpp_sm *dpp)
+{
+	uint8_t hdr[32];
+	uint8_t attrs[256];
+	uint8_t *ptr = attrs;
+	uint64_t m_data[L_ECC_MAX_DIGITS * 2];
+	uint16_t group;
+	struct iovec iov[2];
+	const uint8_t *own_mac = netdev_get_address(dpp->netdev);
+
+	l_put_le16(l_ecc_curve_get_ike_group(dpp->curve), &group);
+
+	iov[0].iov_len = dpp_build_header(own_mac, broadcast,
+				DPP_FRAME_PKEX_VERSION1_XCHG_REQUST, hdr);
+	iov[0].iov_base = hdr;
+
+	ptr += dpp_append_attr(ptr, DPP_ATTR_PROTOCOL_VERSION,
+				&dpp->pkex_version, 1);
+	ptr += dpp_append_attr(ptr, DPP_ATTR_FINITE_CYCLIC_GROUP,
+				&group, 2);
+
+	if (dpp->pkex_id)
+		ptr += dpp_append_attr(ptr, DPP_ATTR_CODE_IDENTIFIER,
+					dpp->pkex_id, strlen(dpp->pkex_id));
+
+	l_ecc_point_get_data(dpp->pkex_m, m_data, sizeof(m_data));
+
+	ptr += dpp_append_attr(ptr, DPP_ATTR_ENCRYPTED_KEY,
+				m_data, dpp->key_len * 2);
+
+	iov[1].iov_base = attrs;
+	iov[1].iov_len = ptr - attrs;
+
+	dpp_send_frame(dpp, iov, 2, dpp->current_freq);
+}
+
+static void dpp_send_commit_reveal_request(struct dpp_sm *dpp)
+{
+	struct iovec iov[2];
+	uint8_t hdr[41];
+	uint8_t attrs[512];
+	uint8_t *ptr = attrs;
+	uint8_t zero = 0;
+	uint8_t a_pub[L_ECC_POINT_MAX_BYTES];
+	ssize_t a_len;
+
+	a_len = l_ecc_point_get_data(dpp->boot_public, a_pub, sizeof(a_pub));
+
+	iov[0].iov_len = dpp_build_header(netdev_get_address(dpp->netdev),
+					dpp->peer_addr,
+					DPP_FRAME_PKEX_COMMIT_REVEAL_REQUEST,
+					hdr);
+	iov[0].iov_base = hdr;
+
+	ptr += dpp_append_wrapped_data(hdr + 26, 6, &zero, 1, ptr,
+			sizeof(attrs), dpp->z, dpp->z_len, 2,
+			DPP_ATTR_BOOTSTRAPPING_KEY, a_len, a_pub,
+			DPP_ATTR_INITIATOR_AUTH_TAG, dpp->u_len, dpp->u);
+
+	iov[1].iov_base = attrs;
+	iov[1].iov_len = ptr - attrs;
+
+	dpp_send_frame(dpp, iov, 2, dpp->current_freq);
+}
+
 static void dpp_roc_started(void *user_data)
 {
 	struct dpp_sm *dpp = user_data;
@@ -1599,6 +1779,16 @@ static void dpp_roc_started(void *user_data)
 			send_authenticate_response(dpp);
 		}
 
+		break;
+	case DPP_STATE_PKEX_EXCHANGE:
+		if (dpp->role == DPP_CAPABILITY_ENROLLEE)
+			dpp_send_pkex_exchange_request(dpp);
+
+		break;
+	case DPP_STATE_PKEX_COMMIT_REVEAL:
+		if (dpp->role == DPP_CAPABILITY_ENROLLEE)
+			dpp_send_commit_reveal_request(dpp);
+
 		break;
 	default:
 		break;
@@ -1627,6 +1817,7 @@ static void dpp_offchannel_timeout(int error, void *user_data)
 		goto protocol_failed;
 
 	switch (dpp->state) {
+	case DPP_STATE_PKEX_EXCHANGE:
 	case DPP_STATE_PRESENCE:
 		break;
 	case DPP_STATE_NOTHING:
@@ -1634,6 +1825,7 @@ static void dpp_offchannel_timeout(int error, void *user_data)
 		return;
 	case DPP_STATE_AUTHENTICATING:
 	case DPP_STATE_CONFIGURING:
+	case DPP_STATE_PKEX_COMMIT_REVEAL:
 		goto next_roc;
 	}
 
@@ -2196,6 +2388,382 @@ static void dpp_handle_presence_announcement(struct dpp_sm *dpp,
 		dpp->channel_switch = true;
 }
 
+static void dpp_pkex_bad_group(struct dpp_sm *dpp, uint16_t group)
+{
+	uint16_t own_group = l_ecc_curve_get_ike_group(dpp->curve);
+
+	/*
+	 * TODO: The spec allows group negotiation, but it is not yet
+	 *       implemented.
+	 */
+	if (!group)
+		return;
+	/*
+	 * Section 5.6.2
+	 * "If the Responder's offered group offers less security
+	 * than the Initiator's offered group, then the Initiator should
+	 * ignore this message"
+	 */
+	if (group < own_group) {
+		l_debug("Offered group %u is less secure, ignoring",
+				group);
+		return;
+	}
+	/*
+	 * Section 5.6.2
+	 * "If the Responder's offered group offers equivalent or better
+	 * security than the Initiator's offered group, then the
+	 * Initiator may choose to abort its original request and try
+	 * another exchange using the group offered by the Responder"
+	 */
+	if (group >= own_group) {
+		l_debug("Offered group %u is the same or more secure, "
+			" but group negotiation is not supported", group);
+		return;
+	}
+}
+
+static void dpp_pkex_bad_code(struct dpp_sm *dpp)
+{
+	_auto_(l_ecc_point_free) struct l_ecc_point *qr = NULL;
+
+	qr = dpp_derive_qr(dpp->curve, dpp->pkex_key, dpp->pkex_id,
+				netdev_get_address(dpp->netdev));
+	if (!qr || l_ecc_point_is_infinity(qr)) {
+		l_debug("Qr computed to zero, new code should be provisioned");
+		return;
+	}
+
+	l_debug("Qr computed successfully but responder indicated otherwise");
+}
+
+static void dpp_handle_pkex_exchange_response(struct dpp_sm *dpp,
+					const uint8_t *from,
+					const uint8_t *body, size_t body_len)
+{
+	struct dpp_attr_iter iter;
+	enum dpp_attribute_type type;
+	size_t len;
+	const uint8_t *data;
+	const uint8_t *status = NULL;
+	uint8_t version = 0;
+	const char *identifier = NULL;
+	size_t identifier_len = 0;
+	const void *key = NULL;
+	size_t key_len = 0;
+	uint16_t group = 0;
+	_auto_(l_ecc_point_free) struct l_ecc_point *n = NULL;
+	_auto_(l_ecc_point_free) struct l_ecc_point *j = NULL;
+	_auto_(l_ecc_point_free) struct l_ecc_point *qr = NULL;
+	_auto_(l_ecc_point_free) struct l_ecc_point *k = NULL;
+	const uint8_t *own_addr = netdev_get_address(dpp->netdev);
+
+	l_debug("PKEX response "MAC, MAC_STR(from));
+
+	if (dpp->state != DPP_STATE_PKEX_EXCHANGE)
+		return;
+
+	if (dpp->role != DPP_CAPABILITY_ENROLLEE)
+		return;
+
+	memcpy(dpp->peer_addr, from, 6);
+
+	dpp_attr_iter_init(&iter, body + 8, body_len - 8);
+
+	while (dpp_attr_iter_next(&iter, &type, &len, &data)) {
+		switch (type) {
+		case DPP_ATTR_STATUS:
+			if (len != 1)
+				return;
+
+			status = data;
+			break;
+		case DPP_ATTR_PROTOCOL_VERSION:
+			if (len != 1)
+				return;
+
+			version = l_get_u8(data);
+			break;
+		case DPP_ATTR_CODE_IDENTIFIER:
+			identifier = (char *) data;
+			identifier_len = len;
+			break;
+		case DPP_ATTR_ENCRYPTED_KEY:
+			if (len != dpp->key_len * 2)
+				return;
+
+			key = data;
+			key_len = len;
+			break;
+		case DPP_ATTR_FINITE_CYCLIC_GROUP:
+			if (len != 2)
+				return;
+
+			group = l_get_le16(data);
+			break;
+		default:
+			break;
+		}
+	}
+
+	if (!status) {
+		l_debug("No status attribute, ignoring");
+		return;
+	}
+
+	if (!key) {
+		l_debug("No encrypted key, ignoring");
+		return;
+	}
+
+	if (*status != DPP_STATUS_OK)
+		goto handle_status;
+
+	if (dpp->pkex_id) {
+		if (!identifier || identifier_len != strlen(dpp->pkex_id) ||
+					strncmp(dpp->pkex_id, identifier,
+						identifier_len)) {
+			l_debug("mismatch identifier, ignoring");
+			return;
+		}
+	}
+
+	if (version && version != dpp->pkex_version) {
+		l_debug("PKEX version does not match, igoring");
+		return;
+	}
+
+	n = l_ecc_point_from_data(dpp->curve, L_ECC_POINT_TYPE_FULL,
+					key, key_len);
+	if (!n) {
+		l_debug("failed to parse peers encrypted key");
+		goto failed;
+	}
+
+	qr = dpp_derive_qr(dpp->curve, dpp->pkex_key, dpp->pkex_id,
+				dpp->peer_addr);
+	if (!qr)
+		goto failed;
+
+	dpp->y_or_x = l_ecc_point_new(dpp->curve);
+
+	/* Y' = N - Qr */
+	l_ecc_point_inverse(qr);
+	l_ecc_point_add(dpp->y_or_x, n, qr);
+
+	/*
+	 * "The resulting ephemeral key, denoted Y’, is then checked whether it
+	 * is the point-at-infinity. If it is not valid, the protocol ends
+	 * unsuccessfully"
+	 */
+	if (l_ecc_point_is_infinity(dpp->y_or_x)) {
+		l_debug("Y' computed to infinity, failing");
+		goto failed;
+	}
+
+	k = l_ecc_point_new(dpp->curve);
+
+	/* K = Y' * x */
+	l_ecc_point_multiply(k, dpp->pkex_private, dpp->y_or_x);
+
+	dpp_derive_z(own_addr, dpp->peer_addr, n, dpp->pkex_m, k,
+				dpp->pkex_key, dpp->pkex_id,
+				dpp->z, &dpp->z_len);
+
+	/* J = a * Y' */
+	j = l_ecc_point_new(dpp->curve);
+
+	l_ecc_point_multiply(j, dpp->boot_private, dpp->y_or_x);
+
+	if (!dpp_derive_u(j, own_addr, dpp->boot_public, dpp->y_or_x,
+				dpp->pkex_public, dpp->u, &dpp->u_len)) {
+		l_debug("failed to compute u");
+		goto failed;
+	}
+
+	/*
+	 * Now that a response was successfully received, start another
+	 * offchannel with more time for the remainder of the protocol. After
+	 * PKEX, authentication will begin which handles the protocol timeout.
+	 * If the remainder of PKEX (commit-reveal exchange) cannot complete in
+	 * this time it will fail.
+	 */
+	dpp->dwell = (dpp->max_roc < 2000) ? dpp->max_roc : 2000;
+	dpp->state = DPP_STATE_PKEX_COMMIT_REVEAL;
+
+	dpp_pkex_property_changed_notify(dpp);
+
+	dpp_start_offchannel(dpp, dpp->current_freq);
+
+	return;
+
+handle_status:
+	switch (*status) {
+	case DPP_STATUS_BAD_GROUP:
+		dpp_pkex_bad_group(dpp, group);
+		break;
+	case DPP_STATUS_BAD_CODE:
+		dpp_pkex_bad_code(dpp);
+		break;
+	default:
+		l_debug("Unhandled status %u", *status);
+		break;
+	}
+
+failed:
+	dpp_reset(dpp);
+}
+
+static bool dpp_pkex_start_authentication(struct dpp_sm *dpp)
+{
+	dpp->uri = dpp_generate_uri(dpp->own_asn1, dpp->own_asn1_len, 2,
+					netdev_get_address(dpp->netdev),
+					&dpp->current_freq, 1, NULL, NULL);
+
+	l_ecdh_generate_key_pair(dpp->curve, &dpp->proto_private,
+					&dpp->own_proto_public);
+
+	l_getrandom(dpp->i_nonce, dpp->nonce_len);
+
+	dpp->peer_asn1 = dpp_point_to_asn1(dpp->peer_boot_public,
+						&dpp->peer_asn1_len);
+
+	dpp->m = dpp_derive_k1(dpp->peer_boot_public, dpp->proto_private,
+				dpp->k1);
+
+	dpp_hash(L_CHECKSUM_SHA256, dpp->peer_boot_hash, 1, dpp->peer_asn1,
+			dpp->peer_asn1_len);
+
+	dpp->state = DPP_STATE_AUTHENTICATING;
+	dpp->mutual_auth = true;
+
+	dpp_pkex_property_changed_notify(dpp);
+
+	if (dpp->role == DPP_CAPABILITY_ENROLLEE) {
+		dpp->new_freq = dpp->current_freq;
+
+		return dpp_send_authenticate_request(dpp);
+	}
+
+	return true;
+}
+
+static void dpp_handle_pkex_commit_reveal_response(struct dpp_sm *dpp,
+					const uint8_t *from,
+					const uint8_t *body, size_t body_len)
+{
+	struct dpp_attr_iter iter;
+	enum dpp_attribute_type type;
+	size_t len;
+	const uint8_t *data;
+	const uint8_t *wrapped = NULL;
+	size_t wrapped_len = 0;
+	uint8_t one = 1;
+	_auto_(l_free) uint8_t *unwrapped = NULL;
+	size_t unwrapped_len = 0;
+	const uint8_t *boot_key = NULL;
+	size_t boot_key_len = 0;
+	const uint8_t *r_auth = NULL;
+	uint8_t v[L_ECC_SCALAR_MAX_BYTES];
+	size_t v_len;
+	_auto_(l_ecc_point_free) struct l_ecc_point *l = NULL;
+
+	l_debug("PKEX commit reveal "MAC, MAC_STR(from));
+
+	if (dpp->state != DPP_STATE_PKEX_COMMIT_REVEAL)
+		return;
+
+	if (dpp->role != DPP_CAPABILITY_ENROLLEE)
+		return;
+
+	/*
+	 * The URI may not have contained a MAC address, if this announcement
+	 * verifies set peer_addr then.
+	 */
+	if (memcmp(from, dpp->peer_addr, 6)) {
+		l_debug("Unexpected source "MAC" expected "MAC, MAC_STR(from),
+						MAC_STR(dpp->peer_addr));
+		return;
+	}
+
+	dpp_attr_iter_init(&iter, body + 8, body_len - 8);
+
+	while (dpp_attr_iter_next(&iter, &type, &len, &data)) {
+		switch (type) {
+		case DPP_ATTR_WRAPPED_DATA:
+			wrapped = data;
+			wrapped_len = len;
+			break;
+		default:
+			break;
+		}
+	}
+
+	if (!wrapped) {
+		l_debug("No wrapped data");
+		return;
+	}
+
+	unwrapped = dpp_unwrap_attr(body + 2, 6, &one, 1, dpp->z, dpp->z_len,
+					wrapped, wrapped_len, &unwrapped_len);
+	if (!unwrapped) {
+		l_debug("Failed to unwrap Reveal-Commit message");
+		return;
+	}
+
+	dpp_attr_iter_init(&iter, unwrapped, unwrapped_len);
+
+	while (dpp_attr_iter_next(&iter, &type, &len, &data)) {
+		switch (type) {
+		case DPP_ATTR_BOOTSTRAPPING_KEY:
+			if (len != dpp->key_len * 2)
+				return;
+
+			boot_key = data;
+			boot_key_len = len;
+			break;
+		case DPP_ATTR_RESPONDER_AUTH_TAG:
+			if (len != 32)
+				return;
+
+			r_auth = data;
+			break;
+		default:
+			break;
+		}
+	}
+
+	dpp->peer_boot_public = l_ecc_point_from_data(dpp->curve,
+							L_ECC_POINT_TYPE_FULL,
+							boot_key, boot_key_len);
+	if (!dpp->peer_boot_public) {
+		l_debug("Peer public bootstrapping key was invalid");
+		goto failed;
+	}
+
+	/* L = b * X' */
+	l = l_ecc_point_new(dpp->curve);
+
+	l_ecc_point_multiply(l, dpp->pkex_private, dpp->peer_boot_public);
+
+	if (!dpp_derive_v(l, dpp->peer_addr, dpp->peer_boot_public,
+				dpp->pkex_public, dpp->y_or_x, v, &v_len)) {
+		l_debug("Failed to derive v");
+		goto failed;
+	}
+
+	if (memcmp(v, r_auth, v_len)) {
+		l_debug("Bootstrapping data did not verify");
+		goto failed;
+	}
+
+	if (dpp_pkex_start_authentication(dpp))
+		return;
+
+failed:
+	dpp_reset(dpp);
+}
+
 static void dpp_handle_frame(struct dpp_sm *dpp,
 				const struct mmpdu_header *frame,
 				const void *body, size_t body_len)
@@ -2230,6 +2798,14 @@ static void dpp_handle_frame(struct dpp_sm *dpp,
 		dpp_handle_presence_announcement(dpp, frame->address_2,
 							body, body_len);
 		break;
+	case DPP_FRAME_PKEX_XCHG_RESPONSE:
+		dpp_handle_pkex_exchange_response(dpp, frame->address_2, body,
+							body_len);
+		break;
+	case DPP_FRAME_PKEX_COMMIT_REVEAL_RESPONSE:
+		dpp_handle_pkex_commit_reveal_response(dpp, frame->address_2,
+							body, body_len);
+		break;
 	default:
 		l_debug("Unhandled DPP frame %u", *ptr);
 		break;
@@ -2286,10 +2862,16 @@ static void dpp_mlme_notify(struct l_genl_msg *msg, void *user_data)
 	if (!dpp)
 		return;
 
-	if (dpp->state <= DPP_STATE_PRESENCE)
+	/*
+	 * Don't retransmit for presence or PKEX exchange if an enrollee, both
+	 * are broadcast frames which don't expect an ack.
+	 */
+	if (dpp->state == DPP_STATE_NOTHING ||
+			dpp->state == DPP_STATE_PRESENCE ||
+			(dpp->state == DPP_STATE_PKEX_EXCHANGE &&
+			dpp->role == DPP_CAPABILITY_ENROLLEE))
 		return;
 
-
 	if (dpp->frame_cookie != cookie)
 		return;
 
@@ -2459,6 +3041,8 @@ static void dpp_create(struct netdev *netdev)
 
 	l_dbus_object_add_interface(dbus, netdev_get_path(netdev),
 					IWD_DPP_INTERFACE, dpp);
+	l_dbus_object_add_interface(dbus, netdev_get_path(netdev),
+					IWD_DPP_PKEX_INTERFACE, dpp);
 
 	dpp_frame_watch(dpp, 0x00d0, dpp_prefix, sizeof(dpp_prefix));
 
@@ -2759,6 +3343,171 @@ static struct l_dbus_message *dpp_dbus_stop(struct l_dbus *dbus,
 	return l_dbus_message_new_method_return(message);
 }
 
+/*
+ * Section 5.6.1
+ * In lieu of specific channel information obtained in a manner outside
+ * the scope of this specification, PKEX responders shall select one of
+ * the following channels:
+ *  - 2.4 GHz: Channel 6 (2.437 GHz)
+ *  - 5 GHz: Channel 44 (5.220 GHz) if local regulations permit
+ *           operation only in the 5.150 – 5.250 GHz band and Channel
+ *           149 (5.745 GHz) otherwise
+ */
+static uint32_t *dpp_default_freqs(struct dpp_sm *dpp, size_t *out_len)
+{
+	struct wiphy *wiphy = wiphy_find_by_wdev(dpp->wdev_id);
+	const uint32_t default_channels[] = { 2437, 5220, 5745 };
+	uint32_t *freqs_out;
+	size_t i;
+	size_t len = 1;
+
+	if (wiphy_get_supported_bands(wiphy) & BAND_FREQ_5_GHZ)
+		len += 2;
+
+	freqs_out = l_new(uint32_t, len);
+
+	for (i = 0; i < 3; i++)
+		freqs_out[i] = default_channels[i];
+
+	*out_len = len;
+	return freqs_out;
+}
+
+static bool dpp_start_pkex_enrollee(struct dpp_sm *dpp, const char *key,
+				const char *identifier)
+{
+	struct station *station = station_find(netdev_get_ifindex(dpp->netdev));
+	_auto_(l_ecc_point_free) struct l_ecc_point *qi = NULL;
+
+	if (station && station_get_connected_network(station)) {
+		l_debug("Already connected, disconnect before enrolling");
+		return false;
+	}
+
+	if (identifier)
+		dpp->pkex_id = l_strdup(identifier);
+
+	dpp->pkex_key = l_strdup(key);
+	memcpy(dpp->peer_addr, broadcast, 6);
+	dpp->role = DPP_CAPABILITY_ENROLLEE;
+	dpp->state = DPP_STATE_PKEX_EXCHANGE;
+	/*
+	 * In theory a driver could support a lesser duration than 200ms. This
+	 * complicates things since we would need to tack on additional
+	 * offchannel requests to meet the 200ms requirement. This could be done
+	 * but for now use max_roc or 200ms, whichever is less.
+	 */
+	dpp->dwell = (dpp->max_roc < 200) ? dpp->max_roc : 200;
+	/* "DPP R2 devices are expected to use PKEXv1 by default" */
+	dpp->pkex_version = 1;
+
+	if (!l_ecdh_generate_key_pair(dpp->curve, &dpp->pkex_private,
+					&dpp->pkex_public))
+		goto failed;
+
+	/*
+	 * "If Qi is the point-at-infinity, the code shall be deleted and the
+	 * user should be notified to provision a new code"
+	 */
+	qi = dpp_derive_qi(dpp->curve, dpp->pkex_key, dpp->pkex_id,
+				netdev_get_address(dpp->netdev));
+	if (!qi || l_ecc_point_is_infinity(qi)) {
+		l_debug("Cannot derive Qi, provision a new code");
+		goto failed;
+	}
+
+	dpp->pkex_m = l_ecc_point_new(dpp->curve);
+
+	if (!l_ecc_point_add(dpp->pkex_m, dpp->pkex_public, qi))
+		goto failed;
+
+	dpp_pkex_property_changed_notify(dpp);
+
+	dpp->freqs = dpp_default_freqs(dpp, &dpp->freqs_len);
+	if (!dpp->freqs)
+		goto failed;
+
+	dpp->current_freq = dpp->freqs[dpp->freqs_idx];
+
+	dpp_reset_protocol_timer(dpp, DPP_PKEX_PROTO_TIMEOUT);
+
+	l_debug("PKEX start enrollee (id=%s)", dpp->pkex_id ?: "unset");
+
+	dpp_start_offchannel(dpp, dpp->current_freq);
+
+	return true;
+
+failed:
+	dpp_reset(dpp);
+	return false;
+}
+
+static bool dpp_parse_pkex_args(struct l_dbus_message *message,
+					const char **key_out,
+					const char **id_out)
+{
+	struct l_dbus_message_iter iter;
+	struct l_dbus_message_iter variant;
+	const char *dict_key;
+	const char *key = NULL;
+	const char *id = NULL;
+
+	if (!l_dbus_message_get_arguments(message, "a{sv}", &iter))
+		return false;
+
+	while (l_dbus_message_iter_next_entry(&iter, &dict_key, &variant)) {
+		if (!strcmp(dict_key, "Code")) {
+			if (!l_dbus_message_iter_get_variant(&variant, "s",
+								&key))
+				return false;
+		} else if (!strcmp(dict_key, "Identifier")) {
+			if (!l_dbus_message_iter_get_variant(&variant, "s",
+								&id))
+				return false;
+		}
+	}
+
+	if (!key)
+		return false;
+
+	if (id && !dpp_check_pkex_identifier(id))
+		return false;
+
+	*key_out = key;
+	*id_out = id;
+
+	return true;
+}
+
+static struct l_dbus_message *dpp_dbus_pkex_start_enrollee(struct l_dbus *dbus,
+						struct l_dbus_message *message,
+						void *user_data)
+{
+	struct dpp_sm *dpp = user_data;
+	const char *key;
+	const char *id;
+	struct station *station = station_find(netdev_get_ifindex(dpp->netdev));
+
+	l_debug("");
+
+	if (dpp->state != DPP_STATE_NOTHING)
+		return dbus_error_busy(message);
+
+	if (station_get_connected_network(station))
+		return dbus_error_busy(message);
+
+	if (!dpp_parse_pkex_args(message, &key, &id))
+		goto invalid_args;
+
+	if (!dpp_start_pkex_enrollee(dpp, key, id))
+		goto invalid_args;
+
+	return l_dbus_message_new_method_return(message);
+
+invalid_args:
+	return dbus_error_invalid_args(message);
+}
+
 static void dpp_setup_interface(struct l_dbus_interface *interface)
 {
 	l_dbus_interface_method(interface, "StartEnrollee", 0,
@@ -2848,6 +3597,14 @@ static void dpp_setup_pkex_interface(struct l_dbus_interface *interface)
 			dpp_dbus_pkex_register_agent, "", "o", "path");
 	l_dbus_interface_method(interface, "UnregisterSharedCodeAgent", 0,
 			dpp_dbus_pkex_unregister_agent, "", "");
+	l_dbus_interface_method(interface, "StartEnrollee", 0,
+			dpp_dbus_pkex_start_enrollee, "", "a{sv}", "args");
+	l_dbus_interface_method(interface, "Stop", 0, dpp_dbus_stop, "", "");
+
+	l_dbus_interface_property(interface, "Started", 0, "b",
+			dpp_pkex_get_started, NULL);
+	l_dbus_interface_property(interface, "Role", 0, "s", dpp_get_role,
+			NULL);
 }
 
 static void dpp_destroy_interface(void *user_data)
-- 
2.25.1

[PATCH v3 9/9] dpp: initial version of PKEX configurator support

[James Prestwood]

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.
---
 src/dpp.c | 640 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 635 insertions(+), 5 deletions(-)

diff --git a/src/dpp.c b/src/dpp.c
index 8b47be5c..e48d695b 100644
--- a/src/dpp.c
+++ b/src/dpp.c
@@ -164,6 +164,7 @@ struct dpp_sm {
 	char *pkex_id;
 	char *pkex_key;
 	uint8_t pkex_version;
+	struct l_ecc_point *peer_encr_key;
 	struct l_ecc_point *pkex_m;
 	/* Ephemeral key Y' or X' for enrollee or configurator */
 	struct l_ecc_point *y_or_x;
@@ -314,6 +315,26 @@ static void *dpp_serialize_iovec(struct iovec *iov, size_t iov_len,
 	return ret;
 }
 
+static void dpp_free_pending_pkex_data(struct dpp_sm *dpp)
+{
+	if (dpp->agent && dpp->agent->pending_id) {
+		l_dbus_cancel(dbus_get_bus(), dpp->agent->pending_id);
+		dpp->agent->pending_id = 0;
+	}
+
+	if (dpp->pkex_id) {
+		l_free(dpp->pkex_id);
+		dpp->pkex_id = NULL;
+	}
+
+	if (dpp->peer_encr_key) {
+		l_ecc_point_free(dpp->peer_encr_key);
+		dpp->peer_encr_key = NULL;
+	}
+
+	memset(dpp->peer_addr, 0, sizeof(dpp->peer_addr));
+}
+
 static void dpp_free_auth_data(struct dpp_sm *dpp)
 {
 	if (dpp->own_proto_public) {
@@ -431,10 +452,7 @@ static void dpp_reset(struct dpp_sm *dpp)
 		dpp->pkex_key = NULL;
 	}
 
-	if (dpp->pkex_id) {
-		l_free(dpp->pkex_id);
-		dpp->pkex_id = NULL;
-	}
+	dpp_free_pending_pkex_data(dpp);
 
 	dpp_free_auth_data(dpp);
 
@@ -1818,6 +1836,18 @@ static void dpp_offchannel_timeout(int error, void *user_data)
 
 	switch (dpp->state) {
 	case DPP_STATE_PKEX_EXCHANGE:
+		if (dpp->role != DPP_CAPABILITY_CONFIGURATOR || !dpp->agent)
+			break;
+
+		/*
+		 * We have a pending agent request but it did not arrive in
+		 * time, we cant assume the enrollee will be waiting around
+		 * for our response so cancel the request and continue waiting
+		 * for another request
+		 */
+		if (dpp->agent->pending_id)
+			dpp_free_pending_pkex_data(dpp);
+		/* Fall through */
 	case DPP_STATE_PRESENCE:
 		break;
 	case DPP_STATE_NOTHING:
@@ -1905,7 +1935,8 @@ static void authenticate_request(struct dpp_sm *dpp, const uint8_t *from,
 	if (util_is_broadcast_address(from))
 		return;
 
-	if (dpp->state != DPP_STATE_PRESENCE)
+	if (dpp->state != DPP_STATE_PRESENCE &&
+				dpp->state != DPP_STATE_AUTHENTICATING)
 		return;
 
 	l_debug("authenticate request");
@@ -2764,6 +2795,516 @@ failed:
 	dpp_reset(dpp);
 }
 
+static void dpp_send_bad_group(struct dpp_sm *dpp, const uint8_t *addr)
+{
+	uint8_t hdr[32];
+	uint8_t attrs[256];
+	uint8_t *ptr = attrs;
+	uint16_t group;
+	uint8_t status = DPP_STATUS_BAD_GROUP;
+	struct iovec iov[2];
+	const uint8_t *own_mac = netdev_get_address(dpp->netdev);
+
+	l_put_le16(l_ecc_curve_get_ike_group(dpp->curve), &group);
+
+	iov[0].iov_len = dpp_build_header(own_mac, addr,
+				DPP_FRAME_PKEX_XCHG_RESPONSE, hdr);
+	iov[0].iov_base = hdr;
+
+	ptr += dpp_append_attr(ptr, DPP_ATTR_STATUS, &status, 1);
+	ptr += dpp_append_attr(ptr, DPP_ATTR_PROTOCOL_VERSION,
+				&dpp->pkex_version, 1);
+	ptr += dpp_append_attr(ptr, DPP_ATTR_FINITE_CYCLIC_GROUP, &group, 2);
+
+	iov[1].iov_base = attrs;
+	iov[1].iov_len = ptr - attrs;
+
+	dpp_send_frame(dpp, iov, 2, dpp->current_freq);
+}
+
+static void dpp_send_bad_code(struct dpp_sm *dpp, const uint8_t *addr)
+{
+	uint8_t hdr[32];
+	uint8_t attrs[256];
+	uint8_t *ptr = attrs;
+	uint8_t status = DPP_STATUS_BAD_CODE;
+	struct iovec iov[2];
+	const uint8_t *own_mac = netdev_get_address(dpp->netdev);
+
+	iov[0].iov_len = dpp_build_header(own_mac, addr,
+				DPP_FRAME_PKEX_XCHG_RESPONSE, hdr);
+	iov[0].iov_base = hdr;
+
+	ptr += dpp_append_attr(ptr, DPP_ATTR_STATUS, &status, 1);
+	ptr += dpp_append_attr(ptr, DPP_ATTR_PROTOCOL_VERSION,
+				&dpp->pkex_version, 1);
+	if (dpp->pkex_id)
+		ptr += dpp_append_attr(ptr, DPP_ATTR_CODE_IDENTIFIER,
+					dpp->pkex_id, strlen(dpp->pkex_id));
+
+	iov[1].iov_base = attrs;
+	iov[1].iov_len = ptr - attrs;
+
+	dpp_send_frame(dpp, iov, 2, dpp->current_freq);
+}
+
+static void dpp_send_pkex_exchange_response(struct dpp_sm *dpp,
+						struct l_ecc_point *n)
+{
+	uint8_t hdr[32];
+	uint8_t attrs[256];
+	uint8_t *ptr = attrs;
+	uint64_t n_data[L_ECC_MAX_DIGITS * 2];
+	uint16_t group;
+	uint8_t status = DPP_STATUS_OK;
+	struct iovec iov[2];
+	const uint8_t *own_mac = netdev_get_address(dpp->netdev);
+
+	l_put_le16(l_ecc_curve_get_ike_group(dpp->curve), &group);
+
+	iov[0].iov_len = dpp_build_header(own_mac, dpp->peer_addr,
+				DPP_FRAME_PKEX_XCHG_RESPONSE, hdr);
+	iov[0].iov_base = hdr;
+
+	ptr += dpp_append_attr(ptr, DPP_ATTR_STATUS, &status, 1);
+
+	if (dpp->pkex_id)
+		ptr += dpp_append_attr(ptr, DPP_ATTR_CODE_IDENTIFIER,
+					dpp->pkex_id, strlen(dpp->pkex_id));
+
+	l_ecc_point_get_data(n, n_data, sizeof(n_data));
+
+	ptr += dpp_append_attr(ptr, DPP_ATTR_ENCRYPTED_KEY,
+				n_data, dpp->key_len * 2);
+
+	iov[1].iov_base = attrs;
+	iov[1].iov_len = ptr - attrs;
+
+	dpp->state = DPP_STATE_PKEX_COMMIT_REVEAL;
+
+	dpp_pkex_property_changed_notify(dpp);
+
+	dpp_send_frame(dpp, iov, 2, dpp->current_freq);
+}
+
+static void dpp_process_pkex_exchange_request(struct dpp_sm *dpp,
+						struct l_ecc_point *m)
+{
+	_auto_(l_ecc_point_free) struct l_ecc_point *n = NULL;
+	_auto_(l_ecc_point_free) struct l_ecc_point *qr = NULL;
+	_auto_(l_ecc_point_free) struct l_ecc_point *qi = NULL;
+	_auto_(l_ecc_point_free) struct l_ecc_point *k = NULL;
+	const uint8_t *own_addr = netdev_get_address(dpp->netdev);
+
+	/* Qi = H(MAC-Initiator | [identifier | ] code) * Pi */
+	qi = dpp_derive_qi(dpp->curve, dpp->pkex_key, dpp->pkex_id,
+				dpp->peer_addr);
+	if (!qi) {
+		l_debug("could not derive Qi");
+		return;
+	}
+
+	/* X' = M - Qi */
+	dpp->y_or_x = l_ecc_point_new(dpp->curve);
+
+	l_ecc_point_inverse(qi);
+	l_ecc_point_add(dpp->y_or_x, m, qi);
+
+	/*
+	 * "The resulting ephemeral key, denoted X’, is checked whether it is
+	 * the point-at-infinity. If it is not valid, the protocol silently
+	 * fails"
+	 */
+	if (l_ecc_point_is_infinity(dpp->y_or_x)) {
+		l_debug("X' is at infinity, ignore message");
+		dpp_reset(dpp);
+		return;
+	}
+
+	qr = dpp_derive_qr(dpp->curve, dpp->pkex_key, dpp->pkex_id, own_addr);
+	if (!qr || l_ecc_point_is_infinity(qr)) {
+		l_debug("Qr did not derive");
+		l_ecc_point_free(dpp->y_or_x);
+		dpp->y_or_x = NULL;
+		goto bad_code;
+	}
+
+	/*
+	 * "The Responder then generates a random ephemeral keypair, y/Y,
+	 * encrypts Y with Qr to obtain the result, denoted N."
+	 */
+	l_ecdh_generate_key_pair(dpp->curve, &dpp->pkex_private,
+					&dpp->pkex_public);
+
+	/* N = Y + Qr */
+	n = l_ecc_point_new(dpp->curve);
+
+	l_ecc_point_add(n, dpp->pkex_public, qr);
+
+	/* K = y * X' */
+
+	k = l_ecc_point_new(dpp->curve);
+
+	l_ecc_point_multiply(k, dpp->pkex_private, dpp->y_or_x);
+
+	/* z = HKDF(<>, info | M.x | N.x | code, K.x) */
+	dpp_derive_z(dpp->peer_addr, own_addr, n, m, k, dpp->pkex_key,
+				dpp->pkex_id, dpp->z, &dpp->z_len);
+
+	dpp_send_pkex_exchange_response(dpp, n);
+
+	return;
+
+bad_code:
+	dpp_send_bad_code(dpp, dpp->peer_addr);
+	return;
+}
+
+static void dpp_pkex_agent_reply(struct l_dbus_message *message,
+					void *user_data)
+{
+	struct dpp_sm *dpp = user_data;
+	const char *error, *text;
+	const char *code;
+
+	dpp->agent->pending_id = 0;
+
+	l_debug("SharedCodeAgent %s path %s replied", dpp->agent->owner,
+			dpp->agent->path);
+
+	if (l_dbus_message_get_error(message, &error, &text)) {
+		l_error("RequestSharedCode(%s) returned %s(\"%s\")",
+				dpp->pkex_id, error, text);
+		goto reset;
+	}
+
+	if (!l_dbus_message_get_arguments(message, "s", &code)) {
+		l_debug("Invalid arguments, check SharedCodeAgent!");
+		goto reset;
+	}
+
+	dpp->pkex_key = l_strdup(code);
+	dpp_process_pkex_exchange_request(dpp, dpp->peer_encr_key);
+
+	return;
+
+reset:
+	dpp_free_pending_pkex_data(dpp);
+}
+
+static bool dpp_pkex_agent_request(struct dpp_sm *dpp)
+{
+	struct l_dbus_message *msg;
+
+	if (!dpp->agent)
+		return false;
+
+	if (L_WARN_ON(dpp->agent->pending_id))
+		return false;
+
+	msg = l_dbus_message_new_method_call(dbus_get_bus(),
+						dpp->agent->owner,
+						dpp->agent->path,
+						IWD_SHARED_CODE_AGENT_INTERFACE,
+						"RequestSharedCode");
+	l_dbus_message_set_arguments(msg, "s", dpp->pkex_id);
+
+
+	dpp->agent->pending_id = l_dbus_send_with_reply(dbus_get_bus(),
+							msg,
+							dpp_pkex_agent_reply,
+							dpp, NULL);
+	return dpp->agent->pending_id != 0;
+}
+
+static void dpp_handle_pkex_exchange_request(struct dpp_sm *dpp,
+					const uint8_t *from,
+					const uint8_t *body, size_t body_len)
+{
+	struct dpp_attr_iter iter;
+	enum dpp_attribute_type type;
+	size_t len;
+	const uint8_t *data;
+	uint8_t version = 0;
+	uint16_t group = 0;
+	const char *id = NULL;
+	size_t id_len = 0;
+	const void *key = NULL;
+	size_t key_len = 0;
+	_auto_(l_ecc_point_free) struct l_ecc_point *m = NULL;
+
+	l_debug("PKEX exchange request "MAC, MAC_STR(from));
+
+	if (dpp->state != DPP_STATE_PKEX_EXCHANGE)
+		return;
+
+	if (dpp->role != DPP_CAPABILITY_CONFIGURATOR)
+		return;
+
+	if (!l_memeqzero(dpp->peer_addr, 6)) {
+		l_debug("Already configuring enrollee, ignoring");
+		return;
+	}
+
+	dpp_attr_iter_init(&iter, body + 8, body_len - 8);
+
+	while (dpp_attr_iter_next(&iter, &type, &len, &data)) {
+		switch (type) {
+		case DPP_ATTR_PROTOCOL_VERSION:
+			if (len != 1)
+				return;
+
+			version = l_get_u8(data);
+			break;
+		case DPP_ATTR_FINITE_CYCLIC_GROUP:
+			if (len != 2)
+				return;
+
+			group = l_get_le16(data);
+			break;
+		case DPP_ATTR_CODE_IDENTIFIER:
+			id = (char *) data;
+			id_len = len;
+			break;
+		case DPP_ATTR_ENCRYPTED_KEY:
+			key = data;
+			key_len = len;
+			break;
+		default:
+			break;
+		}
+	}
+
+	if (!key || !group) {
+		l_debug("initiator did not provide group or key, ignoring");
+		return;
+	}
+
+	if (group != l_ecc_curve_get_ike_group(dpp->curve)) {
+		l_debug("initiator is not using the same group");
+		goto bad_group;
+	}
+
+	/*
+	 * If the group isn't the same the key length won't match, so check
+	 * this here after we've determined the groups are equal
+	 */
+	if (key_len != dpp->key_len * 2) {
+		l_debug("Unexpected encrypted key length");
+		return;
+	}
+
+	if (version && version != dpp->pkex_version) {
+		l_debug("initiator is not using the same version, ignoring");
+		return;
+	}
+
+	if (dpp->pkex_id) {
+		if (!id || !dpp_check_pkex_identifier(id) ||
+					id_len != strlen(dpp->pkex_id) ||
+					strncmp(dpp->pkex_id, id, id_len)) {
+			l_debug("mismatch identifier, ignoring");
+			return;
+		}
+	}
+
+	m = l_ecc_point_from_data(dpp->curve, L_ECC_POINT_TYPE_FULL,
+					key, key_len);
+	if (!m) {
+		l_debug("could not parse key from initiator, ignoring");
+		return;
+	}
+
+	memcpy(dpp->peer_addr, from, 6);
+
+	if (!dpp->pkex_key) {
+		if (!id) {
+			l_debug("Configurator started with agent but enrollee "
+				"sent no identifier, ignoring");
+			return;
+		}
+
+		dpp->pkex_id = l_strndup(id, id_len);
+
+		/* Need to obtain code from agent */
+		if (!dpp_pkex_agent_request(dpp)) {
+			l_debug("Failed to request code from agent!");
+			dpp_free_pending_pkex_data(dpp);
+			return;
+		}
+
+		/* Save the encrypted key/identifier for the agent callback */
+
+		dpp->peer_encr_key = l_steal_ptr(m);
+
+		return;
+	}
+
+	dpp_process_pkex_exchange_request(dpp, m);
+
+	return;
+
+bad_group:
+	dpp_send_bad_group(dpp, from);
+}
+
+static void dpp_send_commit_reveal_response(struct dpp_sm *dpp,
+						const uint8_t *v, size_t v_len)
+{
+	uint8_t hdr[32];
+	uint8_t attrs[256];
+	uint8_t *ptr = attrs;
+	uint8_t one = 1;
+	struct iovec iov[2];
+	const uint8_t *own_mac = netdev_get_address(dpp->netdev);
+	uint8_t b_pub[L_ECC_POINT_MAX_BYTES];
+	size_t b_len;
+
+	b_len = l_ecc_point_get_data(dpp->boot_public, b_pub, sizeof(b_pub));
+
+
+	iov[0].iov_len = dpp_build_header(own_mac, dpp->peer_addr,
+				DPP_FRAME_PKEX_COMMIT_REVEAL_RESPONSE, hdr);
+	iov[0].iov_base = hdr;
+
+	ptr += dpp_append_wrapped_data(hdr + 26, 6, &one, 1, ptr,
+			sizeof(attrs), dpp->z, dpp->z_len, 2,
+			DPP_ATTR_BOOTSTRAPPING_KEY, b_len, b_pub,
+			DPP_ATTR_RESPONDER_AUTH_TAG, v_len, v);
+
+	iov[1].iov_base = attrs;
+	iov[1].iov_len = ptr - attrs;
+
+	dpp_send_frame(dpp, iov, 2, dpp->current_freq);
+}
+
+static void dpp_handle_pkex_commit_reveal_request(struct dpp_sm *dpp,
+					const uint8_t *from,
+					const uint8_t *body, size_t body_len)
+{
+	struct dpp_attr_iter iter;
+	enum dpp_attribute_type type;
+	size_t len;
+	const uint8_t *data;
+	const void *wrapped = NULL;
+	size_t wrapped_len = 0;
+	_auto_(l_free) uint8_t *unwrapped = NULL;
+	size_t unwrapped_len;
+	uint8_t zero = 0;
+	const void *key = 0;
+	size_t key_len = 0;
+	const void *i_auth = NULL;
+	size_t i_auth_len = 0;
+	_auto_(l_ecc_point_free) struct l_ecc_point *j = NULL;
+	_auto_(l_ecc_point_free) struct l_ecc_point *l = NULL;
+	uint8_t u[L_ECC_SCALAR_MAX_BYTES];
+	size_t u_len = 0;
+	uint8_t v[L_ECC_SCALAR_MAX_BYTES];
+	size_t v_len = 0;
+	const uint8_t *own_addr = netdev_get_address(dpp->netdev);
+
+	l_debug("PKEX commit-reveal request "MAC, MAC_STR(from));
+
+	if (dpp->state != DPP_STATE_PKEX_COMMIT_REVEAL)
+		return;
+
+	if (dpp->role != DPP_CAPABILITY_CONFIGURATOR)
+		return;
+
+	dpp_attr_iter_init(&iter, body + 8, body_len - 8);
+
+	while (dpp_attr_iter_next(&iter, &type, &len, &data)) {
+		switch (type) {
+		case DPP_ATTR_WRAPPED_DATA:
+			wrapped = data;
+			wrapped_len = len;
+			break;
+		default:
+			break;
+		}
+	}
+
+	if (!wrapped) {
+		l_debug("No wrapped data");
+		return;
+	}
+
+	unwrapped = dpp_unwrap_attr(body + 2, 6, &zero, 1, dpp->z, dpp->z_len,
+					wrapped, wrapped_len, &unwrapped_len);
+	if (!unwrapped) {
+		l_debug("Failed to unwrap attributes");
+		return;
+	}
+
+	dpp_attr_iter_init(&iter, unwrapped, unwrapped_len);
+
+	while (dpp_attr_iter_next(&iter, &type, &len, &data)) {
+		switch (type) {
+		case DPP_ATTR_BOOTSTRAPPING_KEY:
+			if (len != dpp->key_len * 2)
+				return;
+
+			key = data;
+			key_len = len;
+			break;
+		case DPP_ATTR_INITIATOR_AUTH_TAG:
+			if (len != 32)
+				return;
+
+			i_auth = data;
+			i_auth_len = len;
+			break;
+		default:
+			break;
+		}
+	}
+
+	if (!key || !i_auth) {
+		l_debug("missing attributes");
+		return;
+	}
+
+	dpp->peer_boot_public = l_ecc_point_from_data(dpp->curve,
+					L_ECC_POINT_TYPE_FULL, key, key_len);
+	if (!dpp->peer_boot_public) {
+		l_debug("peers boostrapping key did not validate");
+		goto failed;
+	}
+
+	/* J' = y * A' */
+	j = l_ecc_point_new(dpp->curve);
+
+	l_ecc_point_multiply(j, dpp->pkex_private, dpp->peer_boot_public);
+
+	dpp_derive_u(j, dpp->peer_addr, dpp->peer_boot_public, dpp->pkex_public,
+			dpp->y_or_x, u, &u_len);
+
+	if (memcmp(u, i_auth, i_auth_len)) {
+		l_debug("Initiator auth tag did not verify");
+		goto failed;
+	}
+
+	/* L' = x * B' */
+	l = l_ecc_point_new(dpp->curve);
+
+	l_ecc_point_multiply(l, dpp->boot_private, dpp->y_or_x);
+
+	if (!dpp_derive_v(l, own_addr, dpp->boot_public, dpp->y_or_x,
+				dpp->pkex_public, v, &v_len)) {
+		l_debug("Failed to derive v");
+		goto failed;
+	}
+
+	dpp_send_commit_reveal_response(dpp, v, v_len);
+
+	dpp_pkex_start_authentication(dpp);
+
+	return;
+
+failed:
+	dpp_reset(dpp);
+}
+
 static void dpp_handle_frame(struct dpp_sm *dpp,
 				const struct mmpdu_header *frame,
 				const void *body, size_t body_len)
@@ -2806,6 +3347,14 @@ static void dpp_handle_frame(struct dpp_sm *dpp,
 		dpp_handle_pkex_commit_reveal_response(dpp, frame->address_2,
 							body, body_len);
 		break;
+	case DPP_FRAME_PKEX_VERSION1_XCHG_REQUST:
+		dpp_handle_pkex_exchange_request(dpp, frame->address_2, body,
+							body_len);
+		break;
+	case DPP_FRAME_PKEX_COMMIT_REVEAL_REQUEST:
+		dpp_handle_pkex_commit_reveal_request(dpp, frame->address_2,
+							body, body_len);
+		break;
 	default:
 		l_debug("Unhandled DPP frame %u", *ptr);
 		break;
@@ -3508,6 +4057,83 @@ invalid_args:
 	return dbus_error_invalid_args(message);
 }
 
+static struct l_dbus_message *dpp_start_pkex_configurator(struct dpp_sm *dpp,
+					const char *key, const char *identifier,
+					struct l_dbus_message *message)
+{
+	struct handshake_state *hs = netdev_get_handshake(dpp->netdev);
+	struct station *station = station_find(netdev_get_ifindex(dpp->netdev));
+	struct network *network = station_get_connected_network(station);
+	struct scan_bss *bss = station_get_connected_bss(station);
+	const struct l_settings *settings;
+
+	if (dpp->state != DPP_STATE_NOTHING)
+		return dbus_error_busy(message);
+
+	if (!network || !bss)
+		return dbus_error_not_connected(message);
+
+	settings = network_get_settings(network);
+	if (!settings) {
+		l_debug("No settings for network, is this a known network?");
+		return dbus_error_not_configured(message);
+	}
+
+	if (identifier)
+		dpp->pkex_id = l_strdup(identifier);
+
+	if (key)
+		dpp->pkex_key = l_strdup(key);
+
+	dpp->role = DPP_CAPABILITY_CONFIGURATOR;
+	dpp->state = DPP_STATE_PKEX_EXCHANGE;
+	dpp->current_freq = bss->frequency;
+	dpp->pkex_version = 1;
+	dpp->config = dpp_configuration_new(network_get_settings(network),
+						network_get_ssid(network),
+						hs->akm_suite);
+
+	dpp_reset_protocol_timer(dpp, DPP_PKEX_PROTO_TIMEOUT);
+	dpp_pkex_property_changed_notify(dpp);
+
+	if (dpp->pkex_key)
+		l_debug("Starting PKEX configurator for single enrollee");
+	else
+		l_debug("Starting PKEX configurator with agent");
+
+	return l_dbus_message_new_method_return(message);
+}
+
+static struct l_dbus_message *dpp_dbus_pkex_configure_enrollee(
+						struct l_dbus *dbus,
+						struct l_dbus_message *message,
+						void *user_data)
+{
+	struct dpp_sm *dpp = user_data;
+	const char *key;
+	const char *id;
+
+	l_debug("");
+
+	if (!dpp_parse_pkex_args(message, &key, &id))
+		return dbus_error_invalid_args(message);
+
+	return dpp_start_pkex_configurator(dpp, key, id, message);
+}
+
+static struct l_dbus_message *dpp_dbus_pkex_start_configurator(
+						struct l_dbus *dbus,
+						struct l_dbus_message *message,
+						void *user_data)
+{
+	struct dpp_sm *dpp = user_data;
+
+	if (!dpp->agent)
+		return dbus_error_no_agent(message);
+
+	return dpp_start_pkex_configurator(dpp, NULL, NULL, message);
+}
+
 static void dpp_setup_interface(struct l_dbus_interface *interface)
 {
 	l_dbus_interface_method(interface, "StartEnrollee", 0,
@@ -3599,6 +4225,10 @@ static void dpp_setup_pkex_interface(struct l_dbus_interface *interface)
 			dpp_dbus_pkex_unregister_agent, "", "");
 	l_dbus_interface_method(interface, "StartEnrollee", 0,
 			dpp_dbus_pkex_start_enrollee, "", "a{sv}", "args");
+	l_dbus_interface_method(interface, "ConfigureEnrollee", 0,
+			dpp_dbus_pkex_configure_enrollee, "", "a{sv}", "args");
+	l_dbus_interface_method(interface, "StartConfigurator", 0,
+			dpp_dbus_pkex_start_configurator, "", "");
 	l_dbus_interface_method(interface, "Stop", 0, dpp_dbus_stop, "", "");
 
 	l_dbus_interface_property(interface, "Started", 0, "b",
-- 
2.25.1

Re: [PATCH v3 1/9] dpp: remove scan_periodic_stop calls

[Denis Kenzior]

Hi James,

On 10/31/23 13:47, James Prestwood wrote:
> 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.
> ---
>   src/dpp.c | 4 ----
>   1 file changed, 4 deletions(-)
> 

Patches 1 - 5 applied, thanks.

Regards,
-Denis

Re: [PATCH v3 6/9] doc: PKEX support for DPP

[Denis Kenzior]

Hi James,

On 10/31/23 13:47, James Prestwood wrote:
> 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() will start a PKEX configurator (should be
> already registered) which will query an agent for an enrollees
> shared code. Enrollees are distinguished by the identifier.
> 
> After the PKEX protocol is finished, DPP bootstrapping keys have
> been exchanged and DPP Authentication will start, followed by
> configuration.
> ---
>   doc/device-provisioning-api.txt | 149 ++++++++++++++++++++++++++++++++
>   1 file changed, 149 insertions(+)
> 
> diff --git a/doc/device-provisioning-api.txt b/doc/device-provisioning-api.txt
> index ac204f46..3c6fc74e 100644
> --- a/doc/device-provisioning-api.txt
> +++ b/doc/device-provisioning-api.txt
> @@ -71,3 +71,152 @@ Properties	boolean Started [readonly]
>   
>   			Indicates the DPP URI. This property is only available
>   			when Started is true.
> +
> +
> +Interface	net.connman.iwd.SharedCodeDeviceProvisioning [Experimental]
> +Object path	/net/connman/iwd/{phy0,phy1,...}/{1,2,...}
> +
> +		ConfigureEnrollee(a{sv})
> +
> +			Starts a DPP configurator using a shared code (and
> +			optionally identifier) set in the dictionary argument.
> +			Valid dictionary keys are:
> +
> +			string Code
> +				The shared code to use. The code used by both
> +				parties (configurator and enrollee) must match.
> +
> +			string Identifier
> +				An optional identifier. The identifier used by
> +				both parties must match. Per the DPP spec the
> +				identifier "shall be a UTF-8 string not greater
> +				than eighty (80) octets"
> +
> +			As with the DeviceProvisioning interface, configurators
> +			must be connected to the network they wish to configure
> +			in order to start.
> +
> +			Once started a configurator (acting as a responder) will
> +			listen on the currently connected channel for an
> +			enrollee's initial exchange request which will kick off
> +			the shared code bootstrapping protocol (PKEX). Once
> +			completed DPP will start automatically. Only one
> +			enrollee can be configured per call to
> +			ConfigureEnrollee, i.e. once PKEX/DPP is has finished

"is has finished"?

> +			(including failure) the configurator will stop.
> +
> +			The SharedCode methods have an eventual timeout and will
> +			stop automatically after 2 minutes.
> +
> +			Possible errors:	net.connman.iwd.Busy
> +						net.connman.iwd.NotConnected
> +						net.connman.InvalidArguments
> +
> +		StartEnrollee(a{sv})
> +
> +			Starts a DPP enrollee using a shared code (and
> +			optionally identifier) set in the dictionary argument
> +			(described above in ConfigureEnrollee).
> +
> +			As with the device provisioning interface, enrollees
> +			must be disconnected in order to start.
> +
> +			Once started an enrollee (acting as an initiator) will
> +			iterate channels sending out broadcast exchange requests
> +			waiting for a response from a configurator. A response
> +			will kick off the shared code bootstrapping protocol
> +			(PKEX), followed by DPP if successful. Once the
> +			protocols have completed, or failed, the enrollee will
> +			stop. If failed, StartEnrollee will need to be called
> +			again to retry.
> +
> +			Possible errors:	net.connman.iwd.Busy
> +						net.connman.iwd.InvalidArguments
> +
> +		StartConfigurator()

You are missing return parameters for all of these methods.  Also seems like 
Stop() method isn't documented.

> +
> +			Start a shared code configurator using an agent to
> +			obtain the shared code. This method is meant for an
> +			automated use case where a configurator is capable of
> +			configuring multiple enrollees, and distinguishing
> +			between them by their identifier.
> +
> +			Prior to calling, a SharedCodeAgent must be registered
> +			using RegisterSharedCodeAgent. Only a single agent can
> +			be registered per SharedCodeInterface.

So the one thing to watch out for is that DPP interface can come and go, unlike 
the Manager interface.  Since StartConfigurator() has to be called for each 
protocol attempt, providing the agent as an argument might be be a nicer 
shortcut?  The API is marked experimental, so we can always change this.  You 
will probably know more once you try to implement the API.

Also, it seems to me that StartConfigurator implies that the agent is active. 
If the agent goes away, StartConfigurator() should be aborted, no?

> +
> +			This method behaves nearly the same as ConfigureEnrollee
> +			except upon receiving an enrollees first exchange
> +			request the registered agent will be asked for the
> +			shared code using the RequestSharedCode method.
> +
> +			Though the agent can provide shared codes for multiple
> +			enrollees, this method will only configure a single
> +			enrollee at a time. Once completed it will need to be
> +			called again to configure additional enrollees.
> +
> +			Possible errors:	net.connman.iwd.Busy
> +						net.connman.iwd.NotConnected
> +						net.connman.iwd.NoAgent
> +
> +		void RegisterSharedCodeAgent(object path)
> +
> +			Register the agent object for servicing shared code
> +			requests on the net.connman.iwd.SharedCodeAgent
> +			interface. There may only be one agent registered at a
> +			time per SharedCodeDeviceProvisioning interface.
> +
> +			Possible Errors:	[service].Error.InvalidArguments
> +						[service].Error.AlreadyExists
> +
> +		void UnregisterSharedCodeAgent()
> +
> +			Unregister an existing agent.
> +
> +			Possible Errors:	[service].Error.NotFound
> +
> +Properties	boolean Started [readonly]
> +
> +			True if shared code device provisioning is currently
> +			active. (configurator or enrollee is started)
> +
> +		string Role [readonly, optional]
> +
> +			Indicates the DPP role. Possible values are "enrollee"
> +			or "configurator". This property is only available when
> +			Started is true.
> +
> +SharedCodeAgent hierarchy
> +=========================
> +
> +Service		unique name
> +Interface	net.connman.iwd.SharedCodeAgent [Experimental]
> +Object path	freely definable
> +
> +Methods		void Release() [noreply]
> +
> +			This method gets called when the service daemon
> +			unregisters the agent.

You don't actually call this method.

> +
> +		string RequestSharedCode(object network, string identifier)
> +
> +			This method gets called when a shared code is requested
> +			for a particular enrollee, distingushed by the
> +			identifier. The shared code agent should lookup the
> +			identifier and return the shared code, or return an
> +			error if not found.

Looks like you don't actually call the agent with the network object?

> +
> +			Possible Errors:	[service].Error.Canceled
> +						[service].Error.NotFound
> +
> +		void Cancel(string reason) [noreply]
> +
> +			This method gets called to indicate that the agent
> +			request failed before a reply was returned. The
> +			argument will indicate why the request is being
> +			cancelled and may be "user-canceled", "timed-out" or
> +			"shutdown".

You don't call this method either.
> +
> +Examples	Requesting a shared code for an enrollee identified by "foo"
> +
> +			RequestSharedCode("foo") ==> "super_secret_code"

This signature incorrect as well?

Regards,
-Denis

Re: [PATCH v3 7/9] dpp: SharedCode interface, {Register,Unregister}SharedCodeAgent

[Denis Kenzior]

Hi James,

On 10/31/23 13:47, James Prestwood wrote:
> This adds the SharedCodeDeviceProvisioning interface as well as
> the two agent methods. After the PKEX configurator role is added
> it will need this to request a shared code from a registered agent.
> ---
>   src/dpp.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 100 insertions(+)
> 

<snip>

> @@ -354,6 +373,11 @@ static void dpp_free(struct dpp_sm *dpp)
>   		dpp->boot_private = NULL;
>   	}
>   
> +	if (dpp->agent) {

Call Release()?

> +		pkex_agent_free(dpp->agent);
> +		dpp->agent = NULL;
> +	}
> +
>   	l_free(dpp);
>   }
>   

Regards,
-Denis

Re: [PATCH v3 8/9] dpp: initial version of PKEX enrollee support

[Denis Kenzior]

Hi James,

On 10/31/23 13:47, James Prestwood wrote:
> 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.
> ---
>   src/dpp.c | 765 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
>   1 file changed, 761 insertions(+), 4 deletions(-)
> 

Wish this came before the agent stuff :)

> diff --git a/src/dpp.c b/src/dpp.c
> index 57024a26..8b47be5c 100644
> --- a/src/dpp.c
> +++ b/src/dpp.c
> @@ -53,10 +53,12 @@
>   #include "src/network.h"
>   #include "src/handshake.h"
>   #include "src/nl80211util.h"
> +#include "src/agent.h"
>   

Why is this needed?

>   #define DPP_FRAME_MAX_RETRIES 5
>   #define DPP_FRAME_RETRY_TIMEOUT 1
>   #define DPP_AUTH_PROTO_TIMEOUT 10
> +#define DPP_PKEX_PROTO_TIMEOUT 120
>   
>   static uint32_t netdev_watch;
>   static struct l_genl_family *nl80211;

I'll look at this in more detail once you send v4.

Regards,
-Denis

Re: [PATCH v3 6/9] doc: PKEX support for DPP

[James Prestwood]

Hi Denis,

On 11/2/23 7:07 PM, Denis Kenzior wrote:
> Hi James,
> 
> On 10/31/23 13:47, James Prestwood wrote:
>> 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() will start a PKEX configurator (should be
>> already registered) which will query an agent for an enrollees
>> shared code. Enrollees are distinguished by the identifier.
>>
>> After the PKEX protocol is finished, DPP bootstrapping keys have
>> been exchanged and DPP Authentication will start, followed by
>> configuration.
>> ---
>>   doc/device-provisioning-api.txt | 149 ++++++++++++++++++++++++++++++++
>>   1 file changed, 149 insertions(+)
>>
>> diff --git a/doc/device-provisioning-api.txt 
>> b/doc/device-provisioning-api.txt
>> index ac204f46..3c6fc74e 100644
>> --- a/doc/device-provisioning-api.txt
>> +++ b/doc/device-provisioning-api.txt
>> @@ -71,3 +71,152 @@ Properties    boolean Started [readonly]
>>               Indicates the DPP URI. This property is only available
>>               when Started is true.
>> +
>> +
>> +Interface    net.connman.iwd.SharedCodeDeviceProvisioning [Experimental]
>> +Object path    /net/connman/iwd/{phy0,phy1,...}/{1,2,...}
>> +
>> +        ConfigureEnrollee(a{sv})
>> +
>> +            Starts a DPP configurator using a shared code (and
>> +            optionally identifier) set in the dictionary argument.
>> +            Valid dictionary keys are:
>> +
>> +            string Code
>> +                The shared code to use. The code used by both
>> +                parties (configurator and enrollee) must match.
>> +
>> +            string Identifier
>> +                An optional identifier. The identifier used by
>> +                both parties must match. Per the DPP spec the
>> +                identifier "shall be a UTF-8 string not greater
>> +                than eighty (80) octets"
>> +
>> +            As with the DeviceProvisioning interface, configurators
>> +            must be connected to the network they wish to configure
>> +            in order to start.
>> +
>> +            Once started a configurator (acting as a responder) will
>> +            listen on the currently connected channel for an
>> +            enrollee's initial exchange request which will kick off
>> +            the shared code bootstrapping protocol (PKEX). Once
>> +            completed DPP will start automatically. Only one
>> +            enrollee can be configured per call to
>> +            ConfigureEnrollee, i.e. once PKEX/DPP is has finished
> 
> "is has finished"?
> 
>> +            (including failure) the configurator will stop.
>> +
>> +            The SharedCode methods have an eventual timeout and will
>> +            stop automatically after 2 minutes.
>> +
>> +            Possible errors:    net.connman.iwd.Busy
>> +                        net.connman.iwd.NotConnected
>> +                        net.connman.InvalidArguments
>> +
>> +        StartEnrollee(a{sv})
>> +
>> +            Starts a DPP enrollee using a shared code (and
>> +            optionally identifier) set in the dictionary argument
>> +            (described above in ConfigureEnrollee).
>> +
>> +            As with the device provisioning interface, enrollees
>> +            must be disconnected in order to start.
>> +
>> +            Once started an enrollee (acting as an initiator) will
>> +            iterate channels sending out broadcast exchange requests
>> +            waiting for a response from a configurator. A response
>> +            will kick off the shared code bootstrapping protocol
>> +            (PKEX), followed by DPP if successful. Once the
>> +            protocols have completed, or failed, the enrollee will
>> +            stop. If failed, StartEnrollee will need to be called
>> +            again to retry.
>> +
>> +            Possible errors:    net.connman.iwd.Busy
>> +                        net.connman.iwd.InvalidArguments
>> +
>> +        StartConfigurator()
> 
> You are missing return parameters for all of these methods.  Also seems 
> like Stop() method isn't documented.
> 
>> +
>> +            Start a shared code configurator using an agent to
>> +            obtain the shared code. This method is meant for an
>> +            automated use case where a configurator is capable of
>> +            configuring multiple enrollees, and distinguishing
>> +            between them by their identifier.
>> +
>> +            Prior to calling, a SharedCodeAgent must be registered
>> +            using RegisterSharedCodeAgent. Only a single agent can
>> +            be registered per SharedCodeInterface.
> 
> So the one thing to watch out for is that DPP interface can come and go, 
> unlike the Manager interface.  Since StartConfigurator() has to be 
> called for each protocol attempt, providing the agent as an argument 
> might be be a nicer shortcut?  The API is marked experimental, so we can 
> always change this.  You will probably know more once you try to 
> implement the API.

I had that thought too but was just keeping things consistent. But I'm 
fine removing the register APIs and just passing the path here.

> 
> Also, it seems to me that StartConfigurator implies that the agent is 
> active. If the agent goes away, StartConfigurator() should be aborted, no?

Yes, probably not a bad idea.

> 
>> +
>> +            This method behaves nearly the same as ConfigureEnrollee
>> +            except upon receiving an enrollees first exchange
>> +            request the registered agent will be asked for the
>> +            shared code using the RequestSharedCode method.
>> +
>> +            Though the agent can provide shared codes for multiple
>> +            enrollees, this method will only configure a single
>> +            enrollee at a time. Once completed it will need to be
>> +            called again to configure additional enrollees.
>> +
>> +            Possible errors:    net.connman.iwd.Busy
>> +                        net.connman.iwd.NotConnected
>> +                        net.connman.iwd.NoAgent
>> +
>> +        void RegisterSharedCodeAgent(object path)
>> +
>> +            Register the agent object for servicing shared code
>> +            requests on the net.connman.iwd.SharedCodeAgent
>> +            interface. There may only be one agent registered at a
>> +            time per SharedCodeDeviceProvisioning interface.
>> +
>> +            Possible Errors:    [service].Error.InvalidArguments
>> +                        [service].Error.AlreadyExists
>> +
>> +        void UnregisterSharedCodeAgent()
>> +
>> +            Unregister an existing agent.
>> +
>> +            Possible Errors:    [service].Error.NotFound
>> +
>> +Properties    boolean Started [readonly]
>> +
>> +            True if shared code device provisioning is currently
>> +            active. (configurator or enrollee is started)
>> +
>> +        string Role [readonly, optional]
>> +
>> +            Indicates the DPP role. Possible values are "enrollee"
>> +            or "configurator". This property is only available when
>> +            Started is true.
>> +
>> +SharedCodeAgent hierarchy
>> +=========================
>> +
>> +Service        unique name
>> +Interface    net.connman.iwd.SharedCodeAgent [Experimental]
>> +Object path    freely definable
>> +
>> +Methods        void Release() [noreply]
>> +
>> +            This method gets called when the service daemon
>> +            unregisters the agent.
> 
> You don't actually call this method.
> 
>> +
>> +        string RequestSharedCode(object network, string identifier)
>> +
>> +            This method gets called when a shared code is requested
>> +            for a particular enrollee, distingushed by the
>> +            identifier. The shared code agent should lookup the
>> +            identifier and return the shared code, or return an
>> +            error if not found.
> 
> Looks like you don't actually call the agent with the network object?

Yeah, this was a mistake, there should just be the one string argument.

> 
>> +
>> +            Possible Errors:    [service].Error.Canceled
>> +                        [service].Error.NotFound
>> +
>> +        void Cancel(string reason) [noreply]
>> +
>> +            This method gets called to indicate that the agent
>> +            request failed before a reply was returned. The
>> +            argument will indicate why the request is being
>> +            cancelled and may be "user-canceled", "timed-out" or
>> +            "shutdown".
> 
> You don't call this method either.
>> +
>> +Examples    Requesting a shared code for an enrollee identified by "foo"
>> +
>> +            RequestSharedCode("foo") ==> "super_secret_code"
> 
> This signature incorrect as well?
> 
> Regards,
> -Denis

Re: [PATCH v3 8/9] dpp: initial version of PKEX enrollee support

[James Prestwood]

Hi Denis,

On 11/2/23 7:12 PM, Denis Kenzior wrote:
> Hi James,
> 
> On 10/31/23 13:47, James Prestwood wrote:
>> 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.
>> ---
>>   src/dpp.c | 765 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
>>   1 file changed, 761 insertions(+), 4 deletions(-)
>>
> 
> Wish this came before the agent stuff :)

Yeah, I can reorder them. I did this really just to include some of the 
cleanup functions that only made sense once the agent existed. But I can 
leave them in this commit.

I can also split the configurator patch into two, one implementing 
ConfigureEnrollee() and the other StartConfigurator()

> 
>> diff --git a/src/dpp.c b/src/dpp.c
>> index 57024a26..8b47be5c 100644
>> --- a/src/dpp.c
>> +++ b/src/dpp.c
>> @@ -53,10 +53,12 @@
>>   #include "src/network.h"
>>   #include "src/handshake.h"
>>   #include "src/nl80211util.h"
>> +#include "src/agent.h"
> 
> Why is this needed?
> 
>>   #define DPP_FRAME_MAX_RETRIES 5
>>   #define DPP_FRAME_RETRY_TIMEOUT 1
>>   #define DPP_AUTH_PROTO_TIMEOUT 10
>> +#define DPP_PKEX_PROTO_TIMEOUT 120
>>   static uint32_t netdev_watch;
>>   static struct l_genl_family *nl80211;
> 
> I'll look at this in more detail once you send v4.
> 
> Regards,
> -Denis
>