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FILS: Update PMKID derivation rules for ERP key hierarchy establishment

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IEEE Std 802.11ai-2016 had missed a change in the Pairwise key hierarchy
clause (12.7.1.3 in IEEE Std 802.11-2016) and due to that, the previous
implementation ended up using HMAC-SHA-1 -based PMKID derivation. This
was not really the intent of the FILS design and that issue was fixed
during REVmd work with the changes proposed in
https://mentor.ieee.org/802.11/dcn/17/11-17-0906-04-000m-fils-fixes.docx
that change FILS cases to use HMAC-SHA-256 and HMAC-SHA-384 based on the
negotiated AKM.

Update the implementation to match the new design. This changes the
rsn_pmkid() function to take in the more generic AKMP identifier instead
of a boolean identifying whether SHA256 is used.

Note: This is not backwards compatible, i.e., this breaks PMKSA caching
based on the initial ERP key hierarchy setup if only STA or AP side
implementation is updated. PMKSA caching based on FILS authentication
exchange is not impacted by this, though.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
This commit is contained in:
Jouni Malinen 2017-09-13 17:58:29 +03:00 • committed by Jouni Malinen
parent 3031133983
commit 41b8191485
5 changed files with 33 additions and 16 deletions
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3
src/rsn_supp/pmksa_cache.c
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@ -154,8 +154,7 @@ pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len,
else if (wpa_key_mgmt_suite_b(akmp))
rsn_pmkid_suite_b(kck, kck_len, aa, spa, entry->pmkid);
else
rsn_pmkid(pmk, pmk_len, aa, spa, entry->pmkid,
wpa_key_mgmt_sha256(akmp));
rsn_pmkid(pmk, pmk_len, aa, spa, entry->pmkid, akmp);
os_get_reltime(&now);
entry->expiration = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime;
entry->reauth_time = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime *