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iwd
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netdev: choose correct address on NEW_KEY/SET_STATION 

With the introduction of Ad-Hoc, its not as simple as choosing
aa/spa addresses when setting the keys. Since Ad-Hoc acts as
both the authenticator and supplicant we must check how the netdev
address relates to the particular handshake object as well as
choose the correct key depending on the value of the AA/SPA address.
802.11 states that the higher of the two addresses is to be used
to set the key for the Ad-Hoc connection.

A simple helper was added to choose the correct addressed based on
netdev type and handshake state. netdev_set_tk also checks that
aa > spa in the handshake object when in Ad-Hoc mode. If this is
true then the keys from that handshake are used, otherwise return
and the other handshake key will be used (aa will be > spa).

The station/ap mode behaves exactly the same as before.
This commit is contained in:
James Prestwood 2018-07-16 15:29:18 -07:00 committed by Denis Kenzior
parent 27430287ab
commit 515985afed
1 changed files with 32 additions and 5 deletions
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37
src/netdev.c
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@ -1022,7 +1022,7 @@ static void netdev_set_station_cb(struct l_genl_msg *msg, void *user_data)
nhs->set_station_cmd_id = 0;
if (!netdev->connected)
if (netdev->type == NL80211_IFTYPE_STATION && !netdev->connected)
return;
err = l_genl_msg_get_error(msg);
@ -1250,12 +1250,29 @@ static void netdev_set_igtk(struct handshake_state *hs, uint8_t key_index,
netdev_setting_keys_failed(nhs, MMPDU_REASON_CODE_UNSPECIFIED);
}
static const uint8_t *netdev_choose_key_address(
struct netdev_handshake_state *nhs)
{
switch (nhs->netdev->type) {
case NL80211_IFTYPE_STATION:
return nhs->super.aa;
case NL80211_IFTYPE_AP:
return nhs->super.spa;
case NL80211_IFTYPE_ADHOC:
if (!memcmp(nhs->netdev->addr, nhs->super.aa, 6))
return nhs->super.spa;
else
return nhs->super.aa;
default:
return NULL;
}
}
static void netdev_new_pairwise_key_cb(struct l_genl_msg *msg, void *data)
{
struct netdev_handshake_state *nhs = data;
struct netdev *netdev = nhs->netdev;
const uint8_t *addr = (netdev->type == NL80211_IFTYPE_STATION) ?
nhs->super.aa : nhs->super.spa;
const uint8_t *addr = netdev_choose_key_address(nhs);
nhs->pairwise_new_key_cmd_id = 0;
@ -1313,8 +1330,18 @@ static void netdev_set_tk(struct handshake_state *hs,
struct netdev *netdev = nhs->netdev;
struct l_genl_msg *msg;
enum mmpdu_reason_code rc;
const uint8_t *addr = (netdev->type == NL80211_IFTYPE_STATION) ?
nhs->super.aa : nhs->super.spa;
const uint8_t *addr = netdev_choose_key_address(nhs);
/*
* 802.11 Section 4.10.4.3:
* Because in an IBSS there are two 4-way handshakes between
* any two Supplicants and Authenticators, the pairwise key used
* between any two STAs is from the 4-way handshake initiated
* by the STA Authenticator with the higher MAC address...
*/
if (netdev->type == NL80211_IFTYPE_ADHOC &&
memcmp(nhs->super.aa, nhs->super.spa, 6) < 0)
return;
l_debug("%d", netdev->index);