From 24f0507af460aa6ce637743be8295820b81e8fac Mon Sep 17 00:00:00 2001 From: Ilan Peer Date: Wed, 16 Dec 2020 13:01:40 +0200 Subject: [PATCH] WPA: Support deriving KDK based on capabilities (Authenticator) Derive the KDK as part of PMK to PTK derivation if forced by configuration or in case both the local AP and the peer station declare support for secure LTF. Signed-off-by: Ilan Peer --- src/ap/wpa_auth.c | 29 +++++++++++++++++++++-------- src/ap/wpa_auth.h | 4 ++-- src/ap/wpa_auth_ft.c | 14 ++++++++++---- src/ap/wpa_auth_glue.c | 2 +- 4 files changed, 34 insertions(+), 15 deletions(-) diff --git a/src/ap/wpa_auth.c b/src/ap/wpa_auth.c index e6dfb34d1..acb4416c5 100644 --- a/src/ap/wpa_auth.c +++ b/src/ap/wpa_auth.c @@ -2278,9 +2278,17 @@ static int wpa_derive_ptk(struct wpa_state_machine *sm, const u8 *snonce, struct wpa_ptk *ptk, int force_sha256) { const u8 *z = NULL; - size_t z_len = 0; + size_t z_len = 0, kdk_len; int akmp; + if (sm->wpa_auth->conf.force_kdk_derivation || + (sm->wpa_auth->conf.secure_ltf && + sm->rsnxe && sm->rsnxe_len >= 4 && + sm->rsnxe[3] & BIT(WLAN_RSNX_CAPAB_SECURE_LTF - 8))) + kdk_len = WPA_KDK_MAX_LEN; + else + kdk_len = 0; + #ifdef CONFIG_IEEE80211R_AP if (wpa_key_mgmt_ft(sm->wpa_key_mgmt)) { if (sm->ft_completed) { @@ -2293,8 +2301,7 @@ static int wpa_derive_ptk(struct wpa_state_machine *sm, const u8 *snonce, ptk, ptk_name, sm->wpa_key_mgmt, sm->pairwise, - sm->wpa_auth->conf.kdk ? - WPA_KDK_MAX_LEN : 0); + kdk_len); } return wpa_auth_derive_ptk_ft(sm, ptk); } @@ -2312,8 +2319,7 @@ static int wpa_derive_ptk(struct wpa_state_machine *sm, const u8 *snonce, akmp |= WPA_KEY_MGMT_PSK_SHA256; return wpa_pmk_to_ptk(pmk, pmk_len, "Pairwise key expansion", sm->wpa_auth->addr, sm->addr, sm->ANonce, snonce, - ptk, akmp, sm->pairwise, z, z_len, - sm->wpa_auth->conf.kdk ? WPA_KDK_MAX_LEN : 0); + ptk, akmp, sm->pairwise, z, z_len, kdk_len); } @@ -2328,14 +2334,21 @@ int fils_auth_pmk_to_ptk(struct wpa_state_machine *sm, const u8 *pmk, size_t ick_len; int res; u8 fils_ft[FILS_FT_MAX_LEN]; - size_t fils_ft_len = 0; + size_t fils_ft_len = 0, kdk_len; + + if (sm->wpa_auth->conf.force_kdk_derivation || + (sm->wpa_auth->conf.secure_ltf && + sm->rsnxe && sm->rsnxe_len >= 4 && + sm->rsnxe[3] & BIT(WLAN_RSNX_CAPAB_SECURE_LTF - 8))) + kdk_len = WPA_KDK_MAX_LEN; + else + kdk_len = 0; res = fils_pmk_to_ptk(pmk, pmk_len, sm->addr, sm->wpa_auth->addr, snonce, anonce, dhss, dhss_len, &sm->PTK, ick, &ick_len, sm->wpa_key_mgmt, sm->pairwise, - fils_ft, &fils_ft_len, - sm->wpa_auth->conf.kdk ? WPA_KDK_MAX_LEN : 0); + fils_ft, &fils_ft_len, kdk_len); if (res < 0) return res; sm->PTK_valid = true; diff --git a/src/ap/wpa_auth.h b/src/ap/wpa_auth.h index 0a16141ed..cf0801dc3 100644 --- a/src/ap/wpa_auth.h +++ b/src/ap/wpa_auth.h @@ -270,9 +270,9 @@ struct wpa_auth_config { /* * If set Key Derivation Key should be derived as part of PMK to - * PTK derivation. + * PTK derivation regardless of advertised capabilities. */ - bool kdk; + bool force_kdk_derivation; }; typedef enum { diff --git a/src/ap/wpa_auth_ft.c b/src/ap/wpa_auth_ft.c index 115a6fa2f..32b745651 100644 --- a/src/ap/wpa_auth_ft.c +++ b/src/ap/wpa_auth_ft.c @@ -3066,7 +3066,7 @@ static int wpa_ft_process_auth_req(struct wpa_state_machine *sm, const u8 *identity, *radius_cui; size_t identity_len = 0, radius_cui_len = 0; int use_sha384; - size_t pmk_r1_len; + size_t pmk_r1_len, kdk_len; *resp_ies = NULL; *resp_ies_len = 0; @@ -3196,12 +3196,18 @@ pmk_r1_derived: wpa_hexdump(MSG_DEBUG, "FT: Generated ANonce", sm->ANonce, WPA_NONCE_LEN); + if (sm->wpa_auth->conf.force_kdk_derivation || + (sm->wpa_auth->conf.secure_ltf && + sm->rsnxe && sm->rsnxe_len >= 4 && + sm->rsnxe[3] & BIT(WLAN_RSNX_CAPAB_SECURE_LTF - 8))) + kdk_len = WPA_KDK_MAX_LEN; + else + kdk_len = 0; + if (wpa_pmk_r1_to_ptk(pmk_r1, pmk_r1_len, sm->SNonce, sm->ANonce, sm->addr, sm->wpa_auth->addr, pmk_r1_name, &sm->PTK, ptk_name, sm->wpa_key_mgmt, - pairwise, - sm->wpa_auth->conf.kdk ? - WPA_KDK_MAX_LEN : 0) < 0) + pairwise, kdk_len) < 0) return WLAN_STATUS_UNSPECIFIED_FAILURE; sm->pairwise = pairwise; diff --git a/src/ap/wpa_auth_glue.c b/src/ap/wpa_auth_glue.c index 23025b36a..ebc35dd29 100644 --- a/src/ap/wpa_auth_glue.c +++ b/src/ap/wpa_auth_glue.c @@ -211,7 +211,7 @@ static void hostapd_wpa_auth_conf(struct hostapd_bss_config *conf, #endif /* CONFIG_DPP2 */ #ifdef CONFIG_PASN #ifdef CONFIG_TESTING_OPTIONS - wconf->kdk = conf->force_kdk_derivation; + wconf->force_kdk_derivation = conf->force_kdk_derivation; #endif /* CONFIG_TESTING_OPTIONS */ #endif /* CONFIG_PASN */ }