mirror of
https://git.kernel.org/pub/scm/network/wireless/iwd.git
synced 2024-11-26 10:39:23 +01:00
ap: Set up the GTK and pass to handshake
Set a default GTK cipher type same as our current PTK type, generate a random GTK when the first STA connects and set it up in the kernel, then pass the values that EAPoL is going to need to the handshake_state.
This commit is contained in:
Andrew Zaborowski
Denis Kenzior
parent
01edef9001
commit
36c441c945
257
src/ap.c
257
src/ap.c
@ -50,17 +50,21 @@ struct ap_state {
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char *ssid;
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int channel;
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unsigned int ciphers;
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enum ie_rsn_cipher_suite group_cipher;
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uint32_t beacon_interval;
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struct l_uintset *rates;
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uint8_t pmk[32];
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struct l_queue *frame_watch_ids;
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uint32_t start_stop_cmd_id;
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uint8_t gtk[CRYPTO_MAX_GTK_LEN];
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uint8_t gtk_index;
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uint16_t last_aid;
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struct l_queue *sta_states;
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struct l_dbus_message *pending;
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bool started : 1;
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bool gtk_set : 1;
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};
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struct sta_state {
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@ -76,6 +80,7 @@ struct sta_state {
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uint8_t *assoc_rsne;
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struct eapol_sm *sm;
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struct handshake_state *hs;
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uint32_t gtk_query_cmd_id;
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};
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static struct l_genl_family *nl80211 = NULL;
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@ -91,6 +96,9 @@ static void ap_sta_free(void *data)
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if (sta->assoc_resp_cmd_id)
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l_genl_family_cancel(nl80211, sta->assoc_resp_cmd_id);
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if (sta->gtk_query_cmd_id)
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l_genl_family_cancel(nl80211, sta->gtk_query_cmd_id);
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if (sta->sm)
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eapol_sm_free(sta->sm);
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@ -153,6 +161,11 @@ static void ap_del_station(struct sta_state *sta, uint16_t reason,
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sta->associated = false;
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sta->rsna = false;
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if (sta->gtk_query_cmd_id) {
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l_genl_family_cancel(nl80211, sta->gtk_query_cmd_id);
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sta->gtk_query_cmd_id = 0;
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}
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if (sta->sm)
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eapol_sm_free(sta->sm);
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@ -252,7 +265,7 @@ static void ap_set_rsn_info(struct ap_state *ap, struct ie_rsn_info *rsn)
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memset(rsn, 0, sizeof(*rsn));
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rsn->akm_suites = IE_RSN_AKM_SUITE_PSK;
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rsn->pairwise_ciphers = ap->ciphers;
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rsn->group_cipher = IE_RSN_CIPHER_SUITE_NO_GROUP_TRAFFIC;
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rsn->group_cipher = ap->group_cipher;
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}
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/*
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@ -390,9 +403,8 @@ static void ap_handshake_event(struct handshake_state *hs,
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}
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}
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static void ap_associate_sta_cb(struct l_genl_msg *msg, void *user_data)
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static void ap_start_rsna(struct sta_state *sta, const uint8_t *gtk_rsc)
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{
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struct sta_state *sta = user_data;
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struct ap_state *ap = sta->ap;
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struct netdev *netdev = sta->ap->netdev;
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const uint8_t *own_addr = netdev_get_address(netdev);
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@ -400,12 +412,6 @@ static void ap_associate_sta_cb(struct l_genl_msg *msg, void *user_data)
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struct ie_rsn_info rsn;
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uint8_t bss_rsne[24];
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if (l_genl_msg_get_error(msg) < 0) {
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l_error("NEW_STATION/SET_STATION failed: %i",
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l_genl_msg_get_error(msg));
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return;
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}
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memset(&bss, 0, sizeof(bss));
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ap_set_rsn_info(ap, &rsn);
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@ -427,6 +433,10 @@ static void ap_associate_sta_cb(struct l_genl_msg *msg, void *user_data)
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handshake_state_set_authenticator_address(sta->hs, own_addr);
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handshake_state_set_supplicant_address(sta->hs, sta->addr);
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if (gtk_rsc)
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handshake_state_set_gtk(sta->hs, ap->gtk, ap->gtk_index,
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gtk_rsc);
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sta->sm = eapol_sm_new(sta->hs);
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if (!sta->sm) {
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handshake_state_free(sta->hs);
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@ -446,6 +456,221 @@ error:
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ap_del_station(sta, MMPDU_REASON_CODE_UNSPECIFIED, true);
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}
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static void ap_gtk_query_cb(struct l_genl_msg *msg, void *user_data)
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{
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struct sta_state *sta = user_data;
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struct l_genl_attr attr, nested;
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uint16_t type, len;
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const void *data;
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sta->gtk_query_cmd_id = 0;
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if (l_genl_msg_get_error(msg) < 0 || !l_genl_attr_init(&attr, msg)) {
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l_error("GET_KEY failed for the GTK: %i",
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l_genl_msg_get_error(msg));
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goto error;
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}
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while (l_genl_attr_next(&attr, &type, &len, &data)) {
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if (type != NL80211_ATTR_KEY)
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continue;
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break;
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}
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if (type != NL80211_ATTR_KEY || !l_genl_attr_recurse(&attr, &nested)) {
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l_error("Can't recurse into ATTR_KEY in GET_KEY reply");
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goto error;
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}
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while (l_genl_attr_next(&nested, &type, &len, &data)) {
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if (type != NL80211_KEY_SEQ)
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continue;
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break;
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}
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if (type != NL80211_KEY_SEQ) {
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l_error("KEY_SEQ not returned in GET_KEY reply");
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goto error;
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}
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if (len != 6) {
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l_error("KEY_SEQ length != 6 in GET_KEY reply");
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goto error;
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}
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ap_start_rsna(sta, data);
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return;
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error:
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ap_del_station(sta, MMPDU_REASON_CODE_UNSPECIFIED, true);
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}
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static struct l_genl_msg *ap_build_cmd_new_key(struct ap_state *ap,
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uint32_t cipher, size_t key_len)
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{
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uint32_t ifindex = netdev_get_ifindex(ap->netdev);
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struct l_genl_msg *msg;
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msg = l_genl_msg_new_sized(NL80211_CMD_NEW_KEY, 128);
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l_genl_msg_append_attr(msg, NL80211_ATTR_IFINDEX, 4, &ifindex);
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l_genl_msg_enter_nested(msg, NL80211_ATTR_KEY);
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l_genl_msg_append_attr(msg, NL80211_KEY_IDX, 1, &ap->gtk_index);
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l_genl_msg_append_attr(msg, NL80211_KEY_DATA, key_len, ap->gtk);
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l_genl_msg_append_attr(msg, NL80211_KEY_CIPHER, 4, &cipher);
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l_genl_msg_leave_nested(msg);
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return msg;
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}
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static struct l_genl_msg *ap_build_cmd_set_key(struct ap_state *ap)
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{
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uint32_t ifindex = netdev_get_ifindex(ap->netdev);
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struct l_genl_msg *msg;
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msg = l_genl_msg_new_sized(NL80211_CMD_SET_KEY, 128);
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l_genl_msg_append_attr(msg, NL80211_ATTR_IFINDEX, 4, &ifindex);
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l_genl_msg_enter_nested(msg, NL80211_ATTR_KEY);
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l_genl_msg_append_attr(msg, NL80211_KEY_IDX, 1, &ap->gtk_index);
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l_genl_msg_append_attr(msg, NL80211_KEY_DEFAULT, 0, NULL);
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l_genl_msg_enter_nested(msg, NL80211_KEY_DEFAULT_TYPES);
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l_genl_msg_append_attr(msg, NL80211_KEY_DEFAULT_TYPE_MULTICAST,
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0, NULL);
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l_genl_msg_leave_nested(msg);
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l_genl_msg_leave_nested(msg);
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return msg;
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}
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static struct l_genl_msg *ap_build_cmd_del_key(struct ap_state *ap)
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{
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uint32_t ifindex = netdev_get_ifindex(ap->netdev);
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struct l_genl_msg *msg;
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msg = l_genl_msg_new_sized(NL80211_CMD_DEL_KEY, 128);
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l_genl_msg_append_attr(msg, NL80211_ATTR_IFINDEX, 4, &ifindex);
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l_genl_msg_enter_nested(msg, NL80211_ATTR_KEY);
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l_genl_msg_append_attr(msg, NL80211_KEY_IDX, 1, &ap->gtk_index);
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l_genl_msg_leave_nested(msg);
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return msg;
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}
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static struct l_genl_msg *ap_build_cmd_get_key(struct ap_state *ap)
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{
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uint32_t ifindex = netdev_get_ifindex(ap->netdev);
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struct l_genl_msg *msg;
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msg = l_genl_msg_new_sized(NL80211_CMD_GET_KEY, 128);
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l_genl_msg_append_attr(msg, NL80211_ATTR_IFINDEX, 4, &ifindex);
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l_genl_msg_append_attr(msg, NL80211_ATTR_KEY_IDX, 1, &ap->gtk_index);
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return msg;
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}
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static void ap_gtk_op_cb(struct l_genl_msg *msg, void *user_data)
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{
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if (l_genl_msg_get_error(msg) < 0) {
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uint8_t cmd = l_genl_msg_get_command(msg);
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const char *cmd_name =
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cmd == NL80211_CMD_NEW_KEY ? "NEW_KEY" :
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cmd == NL80211_CMD_SET_KEY ? "SET_KEY" :
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"DEL_KEY";
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l_error("%s failed for the GTK: %i",
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cmd_name, l_genl_msg_get_error(msg));
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}
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}
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static void ap_associate_sta_cb(struct l_genl_msg *msg, void *user_data)
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{
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struct sta_state *sta = user_data;
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struct ap_state *ap = sta->ap;
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if (l_genl_msg_get_error(msg) < 0) {
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l_error("NEW_STATION/SET_STATION failed: %i",
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l_genl_msg_get_error(msg));
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return;
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}
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/*
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* Set up the group key. If this is our first STA then we have
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* to add the new GTK to the kernel. In theory we should be
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* able to supply our own RSC (e.g. generated randomly) and use it
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* immediately for our 4-Way Handshake without querying the kernel.
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* However NL80211_CMD_NEW_KEY only lets us set the receive RSC --
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* the Rx PN for CCMP and the Rx IV for TKIP -- and the
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* transmit RSC always starts as all zeros. There's effectively
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* no way to set the Tx RSC or query the Rx RSC through nl80211.
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* So we query the Tx RSC in both scenarios just in case some
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* driver/hardware uses a different initial Tx RSC.
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*
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* Optimally we would get called back by the EAPoL state machine
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* only when building the step 3 of 4 message to query the RSC as
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* late as possible but that would complicate EAPoL.
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*/
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if (ap->group_cipher != IE_RSN_CIPHER_SUITE_NO_GROUP_TRAFFIC &&
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!ap->gtk_set) {
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enum crypto_cipher group_cipher =
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ie_rsn_cipher_suite_to_cipher(ap->group_cipher);
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int gtk_len = crypto_cipher_key_len(group_cipher);
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/*
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* Generate our GTK. Not following the example derivation
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* method in 802.11-2016 section 12.7.1.4 because a simple
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* l_getrandom is just as good.
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*/
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l_getrandom(ap->gtk, gtk_len);
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ap->gtk_index = 1;
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msg = ap_build_cmd_new_key(ap, group_cipher, gtk_len);
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if (!l_genl_family_send(nl80211, msg, ap_gtk_op_cb, NULL,
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NULL)) {
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l_genl_msg_unref(msg);
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l_error("Issuing NEW_KEY failed");
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goto error;
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}
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msg = ap_build_cmd_set_key(ap);
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if (!l_genl_family_send(nl80211, msg, ap_gtk_op_cb, NULL,
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NULL)) {
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l_genl_msg_unref(msg);
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l_error("Issuing SET_KEY failed");
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goto error;
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}
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/*
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* Set the flag now because any new associating STA will
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* just use NL80211_CMD_GET_KEY from now.
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*/
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ap->gtk_set = true;
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}
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if (ap->group_cipher == IE_RSN_CIPHER_SUITE_NO_GROUP_TRAFFIC)
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ap_start_rsna(sta, NULL);
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else {
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msg = ap_build_cmd_get_key(ap);
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sta->gtk_query_cmd_id = l_genl_family_send(nl80211, msg,
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ap_gtk_query_cb,
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sta, NULL);
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if (!sta->gtk_query_cmd_id) {
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l_genl_msg_unref(msg);
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l_error("Issuing GET_KEY failed");
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goto error;
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}
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}
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return;
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error:
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ap_del_station(sta, MMPDU_REASON_CODE_UNSPECIFIED, true);
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}
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static void ap_associate_sta(struct ap_state *ap, struct sta_state *sta)
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{
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struct l_genl_msg *msg;
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@ -1235,6 +1460,7 @@ static int ap_start(struct ap_state *ap, const char *ssid, const char *psk,
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ap->channel = 6;
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/* TODO: Add all ciphers supported by wiphy */
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ap->ciphers = wiphy_select_cipher(wiphy, 0xffff);
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ap->group_cipher = wiphy_select_cipher(wiphy, 0xffff);
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ap->beacon_interval = 100;
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/* TODO: Use actual supported rates */
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ap->rates = l_uintset_new(200);
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@ -1356,6 +1582,19 @@ static int ap_stop(struct ap_state *ap, struct l_dbus_message *message)
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return -EIO;
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}
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if (ap->gtk_set) {
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struct l_genl_msg *msg;
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ap->gtk_set = false;
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msg = ap_build_cmd_del_key(ap);
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if (!l_genl_family_send(nl80211, msg, ap_gtk_op_cb, NULL,
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NULL)) {
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l_genl_msg_unref(msg);
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l_error("Issuing DEL_KEY failed");
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}
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}
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ap->pending = l_dbus_message_ref(message);
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return 0;
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