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handshake: add FT_OVER_8021X AKM for SHA256 PMKID derivation 

Hostapd commit b6d3fd05e3 changed the PMKID derivation in accordance
with 802.11-2020 which then breaks PMKID validation in IWD. This
breaks the FT-8021x AKM in IWD if the AP uses this hostapd version
since the PMKID doesn't validate during EAPoL.

This updates the PMKID derivation to use the correct SHA hash for
this AKM and adds SHA1 based PMKID checking for interoperability
with older hostapd versions.
This commit is contained in:
James Prestwood 2023-06-20 10:25:33 -07:00 committed by Marcel Holtmann
parent 8c4633ef72
commit 9479c31a72
1 changed files with 32 additions and 2 deletions
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34
src/handshake.c
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@ -756,8 +756,26 @@ bool handshake_state_pmkid_matches(struct handshake_state *s,
uint8_t own_pmkid[16];
enum l_checksum_type sha;
/*
* 802.11-2020 Table 9-151 defines the hashing algorithm to use
* for various AKM's. Note some AKMs are omitted here because they
* export the PMKID individually (SAE/FILS/FT-PSK)
*
* SHA1:
* 00-0F-AC:1 (8021X)
* 00-0F-AC:2 (PSK)
*
* SHA256:
* 00-0F-AC:3 (FT-8021X)
* 00-0F-AC:5 (8021X-SHA256)
* 00-0F-AC:6 (PSK-SHA256)
*
* SHA384:
* 00-0F-AC:13 (FT-8021X-SHA384)
*/
if (s->akm_suite & (IE_RSN_AKM_SUITE_8021X_SHA256 |
IE_RSN_AKM_SUITE_PSK_SHA256))
IE_RSN_AKM_SUITE_PSK_SHA256 |
IE_RSN_AKM_SUITE_FT_OVER_8021X))
sha = L_CHECKSUM_SHA256;
else
sha = L_CHECKSUM_SHA1;
@ -765,7 +783,19 @@ bool handshake_state_pmkid_matches(struct handshake_state *s,
if (!handshake_state_get_pmkid(s, own_pmkid, sha))
return false;
return l_secure_memcmp(own_pmkid, check, 16) == 0;
if (l_secure_memcmp(own_pmkid, check, 16)) {
if (s->akm_suite != IE_RSN_AKM_SUITE_FT_OVER_8021X)
return false;
l_debug("PMKID did not match, trying SHA1 derivation");
if (!handshake_state_get_pmkid(s, own_pmkid, L_CHECKSUM_SHA1))
return false;
return l_secure_memcmp(own_pmkid, check, 16) == 0;
}
return true;
}
void handshake_state_set_gtk(struct handshake_state *s, const uint8_t *key,