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netdev: Handle the FT Reassociation Response message

Validate the fourth message of the fast transition sequence and save the
new keys and state as current values in the netdev object.  The
FT-specific IE validation that was already present in the initial MD
is moved to a new function.
This commit is contained in:
Andrew Zaborowski 2017-01-12 03:36:02 -05:00 committed by Denis Kenzior
parent 0854b90687
commit 8bacbf01e4

View File

@ -1102,6 +1102,130 @@ static void netdev_set_rekey_offload(uint32_t ifindex,
}
/*
* Handle the Association Response IE contents either as part of an
* FT initial Mobility Domain association (12.4) or a Fast Transition
* (12.8.5).
*/
static bool netdev_handle_associate_resp_ies(struct handshake_state *hs,
const uint8_t *rsne, const uint8_t *mde,
const uint8_t *fte, bool transition)
{
const uint8_t *sent_mde = hs->mde;
bool is_rsn = hs->own_ie != NULL;
/*
* During a transition in an RSN, check for an RSNE containing the
* PMK-R1-Name and the remaining fields same as in the advertised
* RSNE.
*
* 12.8.5: "The RSNE shall be present only if dot11RSNAActivated is
* true. If present, the RSNE shall be set as follows:
* Version field shall be set to 1.
* PMKID Count field shall be set to 1.
* PMKID field shall contain the PMKR1Name
* All other fields shall be identical to the contents of the RSNE
* advertised by the target AP in Beacon and Probe Response frames."
*/
if (transition && is_rsn) {
struct ie_rsn_info msg4_rsne;
if (!rsne)
return false;
if (ie_parse_rsne_from_data(rsne, rsne[1] + 2,
&msg4_rsne) < 0)
return false;
if (msg4_rsne.num_pmkids != 1 ||
memcmp(msg4_rsne.pmkids, hs->pmk_r1_name, 16))
return false;
if (!handshake_util_ap_ie_matches(rsne, hs->ap_ie, false))
return false;
} else {
if (rsne)
return false;
}
/* An MD IE identical to the one we sent must be present */
if (sent_mde && (!mde || memcmp(sent_mde, mde, sent_mde[1] + 2)))
return false;
/*
* An FT IE is required in an initial mobility domain
* association and re-associations in an RSN but not present
* in a non-RSN (12.4.2 vs. 12.4.3).
*/
if (sent_mde && is_rsn && !fte)
return false;
if (!(sent_mde && is_rsn) && fte)
return false;
if (fte) {
struct ie_ft_info ft_info;
if (ie_parse_fast_bss_transition_from_data(fte, fte[1] + 2,
&ft_info) < 0)
return false;
/* Validate the FTE contents */
if (transition) {
/*
* In an RSN, check for an FT IE with the same
* R0KH-ID, R1KH-ID, ANonce and SNonce that we
* received in message 2, MIC Element Count
* of 6 and the correct MIC.
* TODO: parse and use the GTK and IGTK subelements.
*/
uint8_t mic[16];
if (!ft_calculate_fte_mic(hs, 6, rsne, fte, NULL, mic))
return false;
if (ft_info.mic_element_count != 3 ||
memcmp(ft_info.mic, mic, 16))
return false;
if (hs->r0khid_len != ft_info.r0khid_len ||
memcmp(hs->r0khid, ft_info.r0khid,
hs->r0khid_len) ||
!ft_info.r1khid_present ||
memcmp(hs->r1khid, ft_info.r1khid, 6))
return false;
if (memcmp(ft_info.anonce, hs->anonce, 32))
return false;
if (memcmp(ft_info.snonce, hs->snonce, 32))
return false;
} else {
/* Initial MD association */
uint8_t zeros[32] = {};
handshake_state_set_fte(hs, fte);
/*
* 12.4.2: "The FTE shall have a MIC information
* element count of zero (i.e., no MIC present)
* and have ANonce, SNonce, and MIC fields set to 0."
*/
if (ft_info.mic_element_count != 0 ||
memcmp(ft_info.mic, zeros, 16) ||
memcmp(ft_info.anonce, zeros, 32) ||
memcmp(ft_info.snonce, zeros, 32))
return false;
handshake_state_set_kh_ids(hs, ft_info.r0khid,
ft_info.r0khid_len,
ft_info.r1khid);
}
}
return true;
}
static void netdev_connect_event(struct l_genl_msg *msg,
struct netdev *netdev)
{
@ -1111,6 +1235,9 @@ static void netdev_connect_event(struct l_genl_msg *msg,
const uint16_t *status_code = NULL;
const uint8_t *ies = NULL;
size_t ies_len;
const uint8_t *rsne = NULL;
const uint8_t *mde = NULL;
const uint8_t *fte = NULL;
bool is_rsn = netdev->handshake->own_ie != NULL;
l_debug("");
@ -1145,19 +1272,20 @@ static void netdev_connect_event(struct l_genl_msg *msg,
goto error;
/* Check 802.11r IEs */
if (netdev->handshake->mde && !ies)
goto error;
if (ies) {
struct ie_tlv_iter iter;
const uint8_t *mde = NULL;
const uint8_t *fte = NULL;
const uint8_t *sent_mde = netdev->handshake->mde;
ie_tlv_iter_init(&iter, ies, ies_len);
while (ie_tlv_iter_next(&iter)) {
switch (ie_tlv_iter_get_tag(&iter)) {
case IE_TYPE_RSN:
if (rsne)
goto error;
rsne = ie_tlv_iter_get_data(&iter) - 2;
break;
case IE_TYPE_MOBILITY_DOMAIN:
if (mde)
goto error;
@ -1173,62 +1301,33 @@ static void netdev_connect_event(struct l_genl_msg *msg,
break;
}
}
/* An MD IE identical to the one we sent must be present */
if (sent_mde && (!mde || memcmp(sent_mde, mde,
sent_mde[1] + 2)))
goto error;
/*
* An FT IE is required in an initial mobility domain
* association and re-associations in an RSN but not present
* in a non-RSN (12.4.2 vs. 12.4.3).
*/
if (sent_mde && !is_rsn && fte)
goto error;
if (sent_mde && is_rsn) {
struct ie_ft_info ft_info;
uint8_t zeros[32];
if (!fte)
goto error;
handshake_state_set_fte(netdev->handshake, fte);
if (ie_parse_fast_bss_transition_from_data(fte,
fte[1] + 2,
&ft_info) < 0)
goto error;
/*
* 12.4.2: "The FTE shall have a MIC information
* element count of zero (i.e., no MIC present)
* and have ANonce, SNonce, and MIC fields set to 0."
*/
memset(zeros, 0, 32);
if (ft_info.mic_element_count != 0 ||
memcmp(ft_info.mic, zeros, 16) ||
memcmp(ft_info.anonce, zeros, 32) ||
memcmp(ft_info.snonce, zeros, 32))
goto error;
handshake_state_set_kh_ids(netdev->handshake,
ft_info.r0khid,
ft_info.r0khid_len,
ft_info.r1khid);
}
}
if (!netdev_handle_associate_resp_ies(netdev->handshake, rsne, mde, fte,
netdev->in_ft))
goto error;
if (netdev->sm) {
/*
* Start processing EAPoL frames now that the state machine
* has all the input data even in FT mode.
*/
eapol_start(netdev->sm);
}
if (netdev->in_ft) {
netdev->in_ft = false;
netdev->operational = true;
if (is_rsn)
handshake_state_install_ptk(netdev->handshake);
if (netdev->connect_cb) {
netdev->connect_cb(netdev, NETDEV_RESULT_OK,
netdev->user_data);
netdev->connect_cb = NULL;
}
} else if (is_rsn) {
if (netdev->event_filter)
netdev->event_filter(netdev,
NETDEV_EVENT_4WAY_HANDSHAKE,